JP2002193091A - Master cylinder stroke adjustment device - Google Patents

Abstract

(57) [Summary] [Problem] Even if the wheel cylinder (WCY) pressure changes,
Adjust the stroke on the input side to be the same as the stroke during normal brake operation. When a master cylinder (MCY) 1 generates MCY pressure by advancing a primary inner piston 9, MC
A pump of a brake force control device provided between Y1 and WCY sucks brake fluid from MCY1 and discharges it to WCY, and WCY controlled according to various brake operations.
Pressure develops. This WCY pressure is applied to the braking force control pressure chamber 40.
And acts on the step 8e of the primary outer piston 8. The outer piston 8 is driven by MCY pressure, W
It moves relative to the primary inner piston 9 such that the force due to the CY pressure, the force due to the spring force of the control spring 13, and the sliding resistance force of the portion where the primary outer piston 8 slides in a liquid-tight manner balance the pedal stroke. Is adjusted in the same manner as during normal braking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake system in which when a master cylinder pressure is generated, a brake fluid is sucked from a master cylinder by a pump and discharged to a wheel cylinder side to control the wheel cylinder pressure. A master cylinder stroke adjusting device which belongs to the technical field of a master cylinder used for a vehicle, and in particular, prevents a stroke from changing during another brake operation such as a regenerative cooperative brake operation or a brake assist operation other than a normal brake operation. Belongs to the technical field. In the following description, the master cylinder is referred to as MCY,
Further, the wheel cylinder is also described as WCY.

[0002]

2. Description of the Related Art For example, in a brake system of an automobile, a brake hydraulic booster which generates a large brake hydraulic pressure by boosting a pedal pressure of a brake pedal to a predetermined magnitude by a hydraulic pressure is conventionally used. ing. This brake hydraulic booster can obtain a large brake force with a small brake pedal depression force, thereby ensuring braking and reducing the driver's labor.

In such a conventional brake hydraulic booster, a control valve is operated by an input based on a pedaling force of a brake pedal to generate a hydraulic pressure according to the input, and the hydraulic pressure is supplied to a power chamber. With the introduction, the input is boosted at a predetermined boost ratio and output. Then, the piston of the brake master cylinder is operated by the output of the brake hydraulic pressure booster, and the MCY generates the MCY pressure,
The brake is actuated by introducing the MCY pressure into the wheel cylinder as brake fluid pressure.

[0004]

By the way, in the conventional brake system, various ordinary brake systems using MCY pressure which are used in combination with other brake systems such as a regenerative cooperative brake system and a brake assist system have been proposed. I have. As such a brake system, a brake system that controls the wheel cylinder pressure by suctioning the brake fluid from the MCY and discharging the brake fluid to the wheel cylinder side when the MCY pressure is generated has been considered. In this brake system, for example, when the regenerative braking operation is performed, it is necessary to reduce the braking force by the wheel cylinder by the amount of the regenerative braking force. Also,
Since it is necessary to generate a larger braking force during the brake assist operation than during the normal brake operation, the wheel cylinder pressure is controlled to be higher than during the normal brake operation.

[0005] However, if the wheel cylinder pressure is controlled to be lower than that during normal brake operation for the same input, the amount of brake sucked from the MCY by the pump decreases, and the stroke of the master cylinder piston, that is, the brake pedal pedal The stroke on the input side such as the stroke becomes small. Further, if the wheel cylinder pressure is controlled to be higher than that during normal brake operation for the same input, the amount of brake sucked from the MCY by the pump increases, and the stroke on the input side increases accordingly. As described above, when the stroke on the input side is changed at the time of various brake operations, there is a problem that the brake operation feeling deteriorates. Moreover, if the wheel cylinder pressure changes during various braking operations,
The input of the master cylinder also changes, and the brake feeling further worsens.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to make the stroke on the input side the same as, for example, the stroke at the time of normal brake operation even if the wheel cylinder pressure changes. An object of the present invention is to provide a master cylinder stroke adjusting device capable of performing various adjustments. It is another object of the present invention to provide a master cylinder stroke adjusting device capable of preventing an input from changing even when a wheel cylinder pressure changes.

[0007]

According to a first aspect of the present invention, there is provided a master cylinder hydraulic pressure chamber having a master cylinder piston for generating a master cylinder pressure. In a master cylinder which can be supplied to a cylinder, a stroke of the master cylinder piston is controlled by a wheel cylinder pressure controlled by discharging a brake fluid in the master cylinder hydraulic chamber to the wheel cylinder by a pump. It is characterized by:

[0008] The invention of claim 2 is characterized in that the stroke adjusting device is provided coaxially with the master cylinder piston in the master cylinder. Further, the invention according to claim 3 is characterized in that the master cylinder piston comprises a first piston which is stroked by the input and a second piston which is provided to the first piston in a liquid-tight and relatively slidable manner. The stroke of the first piston is adjusted by applying the wheel cylinder pressure to the second piston and sliding the second piston relative to the first piston.

Further, according to a fourth aspect of the present invention, the second piston is formed in a cylindrical shape having an outer peripheral step portion, and the second piston is formed in an axial hole of the housing or a cylindrical member fixed to the housing. Liquid-tightly and slidably fitted in the holes,
The first piston is fitted in the second piston in a liquid-tight and relatively slidable manner, and the outer peripheral step of the second piston defines an outer periphery of the second piston and an inside of an axial hole of the housing. A brake force control pressure chamber formed between the circumference and the inner circumference of the inner hole of the cylindrical member, and into which the wheel cylinder pressure is introduced, and the wheel introduced into the brake force control pressure chamber The stroke of the first piston is adjusted by applying a cylinder pressure to an outer peripheral step of the second piston.

Further, according to a fifth aspect of the present invention, the second piston is formed in a cylindrical shape having an inner peripheral step.
The first piston is fitted in the second piston in a liquid-tight and relatively slidable manner. And a braking force control pressure chamber, into which the wheel cylinder pressure is introduced,
The stroke of the first piston is adjusted by causing the wheel cylinder pressure introduced into the brake force control pressure chamber to act on the inner peripheral step of the second piston.

Further, according to a sixth aspect of the present invention, an input shaft that is stroked by an input by a brake operating force is provided so as to be relatively movable with respect to the master cylinder piston, and the input shaft and the master cylinder piston are connected to each other. A control spring for controlling the stroke of the input shaft is contracted between the input shaft and the input and the spring force of the control spring act on the input shaft in the same direction. The input and the control spring are opposed to the spring force, and the wheel cylinder pressure is adjusted so that the force due to the wheel cylinder pressure and the input and the control spring spring force are balanced. It is characterized by being controlled.

Further, the invention of claim 7 is characterized in that the stroke adjusting device is provided at a position off the center axis of the master cylinder piston. Further, the invention of claim 8 has a stroke adjusting piston for adjusting a stroke of the master cylinder piston,
The master cylinder pressure is applied in one direction to the stroke adjusting piston, and the wheel cylinder pressure is applied in a direction opposite to the master cylinder pressure to cause the stroke adjusting piston to perform the stroke. It is characterized by adjusting the stroke of the piston.

Further, according to a ninth aspect of the present invention, the stroke adjusting piston has one side formed in a large-diameter piston portion and the other side formed in a small-diameter piston portion. The cylinder pressure is applied, and the wheel cylinder pressure is applied to the small-diameter piston portion.

Further, according to a tenth aspect of the present invention, the stroke adjusting piston has one side formed in a large-diameter piston portion and the other side formed in a small-diameter piston portion. The cylinder pressure is applied, and the wheel cylinder pressure acts on a step between the large-diameter piston portion and the small-diameter piston portion.

Further, the invention of claim 11 is provided with an urging means for urging the stroke adjusting piston in a direction opposite to the direction in which the master cylinder pressure acts, and a force by the master cylinder pressure is applied to the wheel. The wheel cylinder pressure is controlled so as to balance the force of the cylinder pressure and the urging force of the urging means.

Further, the invention according to claim 12 is characterized in that the large-diameter piston portion is sealed with a metal seal, and the small-diameter piston portion is sealed with at least one of a metal seal and an elastic seal. I have. Further, the invention of claim 13 is characterized in that when the pump fails, the master cylinder pressure is supplied to the wheel cylinder.

Further, in the invention according to claim 14, the input is:
A brake booster, which boosts the operating force of the brake operation at a predetermined servo ratio with the pressure of the pressure source and outputs the boosted force, is applied to the master piston. It is characterized in that it is set smaller than the servo ratio for Further, the invention of claim 15 is characterized in that the brake booster outputs the operating force of the brake operation without boosting when the pressure source fails.

[0018]

In the master cylinder stroke adjusting device of the present invention having the above-described structure, the stroke of the master cylinder piston is adjusted by controlling the operation of the stroke adjusting device by the wheel cylinder pressure. Therefore, the master cylinder stroke adjusting device of the present invention can be used even when the wheel cylinder pressure changes variously for the same input by other various brake operations such as a normal brake operation, a regenerative cooperative brake operation, or a brake assist operation. Thus, the stroke of the master cylinder piston can be made the same as the stroke during normal brake operation.

In this case, according to the third aspect of the invention, it is possible to make the stroke of the master cylinder piston the same as the stroke at the time of normal brake operation regardless of the various brake operations. Is changed according to the change of the wheel cylinder pressure. Therefore, it is preferable that the stroke adjusting device for a master cylinder according to the third aspect of the present invention be applied to a brake system that does not cause any trouble even if the input changes as described above.

In each of the inventions of claims 4 to 10,
As described above, regardless of various braking operations, the stroke of the master cylinder piston can be made the same as the stroke during normal braking operation. It does not change even if it changes. Therefore, the master cylinder stroke adjusting device according to each of the fourth to seventh aspects of the present invention can be suitably used for various brake operations.

Further, in each of the inventions according to claims 7 to 12,
The stroke adjusting device is provided at a position off the center axis of the primary piston of the master cylinder.
Therefore, the structures of the master cylinder and the stroke adjusting device are simplified, the assemblability is improved, and the cost is reduced. In addition, since the structure is simplified, the position of the sliding resistance of the stroke adjusting device is reduced, so that the accuracy of the stroke control by the stroke adjusting device is further improved.

Further, according to the thirteenth aspect, when the pump fails, the master cylinder pressure is directly supplied to the wheel cylinder. Therefore, even if the pump fails, the brake is operated by the master cylinder pressure. Further, since the servo ratio of the brake booster is set smaller than the servo ratio for normal brake operation, a smaller brake booster can be adopted.

Furthermore, in the invention of claim 15, the brake booster outputs the operating force of the brake operation without boosting when the pressure source fails. Therefore, since the master cylinder piston is operated by the output of the brake booster, the master cylinder pressure is reliably generated in the master cylinder hydraulic chamber even when the pressure source fails.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a first example of an embodiment of a master cylinder according to the present invention. In the following description, “before” indicates the left side of each figure and “rear” indicates the right side of each figure.

As shown in FIG. 1, the master cylinder 1 in the first example has a housing 2 which has a first hole 3 opening at the right end,
A second hole 4 formed continuously at the left end of the first hole 3 and having a diameter smaller than the diameter of the first hole 3, and a second hole 4 formed continuously at the left end of the second hole 4. It has a stepped hole which is closed at the front end and is made up of a third hole 5 having a smaller diameter.

In the second hole 4 of the stepped hole, a first cylindrical member 6 is fitted in a liquid-tight manner.
Extends through the first hole 3 to the rear of the housing 2. Further, a bottomed second cylindrical member 7 is fitted in the first hole 3 in a liquid-tight manner. The second cylindrical member 7 has a male screw portion 7a at the rear end thereof which is screwed to the female screw portion 2a of the housing 2. The male screw portion 7a is screwed into the female screw portion 2a to fix the second cylindrical member 7 immovably in the axial direction, and the first cylindrical member 6 has the second hole 4 and the third hole 5 Between the step portion 2b of the housing 2 and the rear end bottom portion 7b of the second cylindrical member 7 so as to be immovable in the axial direction.

A cylindrical primary outer piston (corresponding to the second piston of the present invention) 8 is fitted in the first cylindrical member 6 in a liquid-tight and slidable manner. Penetrates the second cylindrical member 7 in a liquid-tight and slidable manner, and extends behind the second cylindrical member 7. The primary outer piston 8 has a large-diameter portion 8a that slidably fits the first cylindrical member 6 in a liquid-tight manner, and a large-diameter portion 8 that penetrates the second cylindrical member 7 in a liquid-tight manner.
The stepped piston is formed from a small diameter portion 8b slightly smaller than the diameter a.

Further, a primary inner piston 9 (corresponding to the first piston of the present invention) 9 is fitted in the primary outer piston 8 in a liquid-tight and slidable manner, and the primary inner piston 9 is Large-diameter portion 9a into which outer piston 8 is slidably fitted in a liquid-tight manner.
A first middle diameter portion 9b projecting forward from the large diameter portion 9a and having a smaller diameter than the large diameter portion 9a; and a small diameter portion 9c projecting forward from the first middle diameter portion 9b and having a smaller diameter than the first middle diameter portion 9b. And a second intermediate diameter portion 9d projecting rearward from the large diameter portion 9a and having a smaller diameter than the large diameter portion 9a, to form a stepped piston. The primary inner piston 9 is adapted to receive an output of a conventionally known brake booster such as a negative pressure booster (not shown in this example), and the brake booster is conventionally known. The operation is controlled by a brake pedal (not shown).

In this case, the servo ratio of the brake booster used together with the MCY1 of the first example is set smaller than that of the conventionally known brake booster. That is, during normal brake operation, MCY1 of this example is used.
The output of the brake booster used for the same is set to be smaller than the output of the conventionally known brake booster for the same input. Therefore, at the time of normal brake operation, the MCY1 is actuated by the output of the brake booster so that the MCY pressure generated by the MCY1 is boosted by the brake force control device as described later so that the brake force required for the normal brake operation is obtained. Has been.

First and second spring retainers 10, 11 are provided on the second middle diameter portion 9d of the primary inner piston 9.
The first spring retainer 10 abuts the outer peripheral step 9e of the large diameter portion 9a and the second intermediate diameter portion 9d, thereby restricting the primary inner piston 9 from moving forward. In addition, the contact of the primary outer piston 8 with the first inner peripheral step 8c restricts the primary outer piston 8 from moving forward. Also, the second spring retainer 1
1 abuts against a stopper ring 12 attached to the rear end of the second middle diameter portion 9d, thereby restricting the movement of the primary inner piston 9 to the rear. 2 inner peripheral step 8d
, The forward movement of the primary outer piston 8 is restricted. And
These first and second spring retainers 10, 11
Between them, a control spring (corresponding to the stroke control spring of the present invention) 13 is contracted.

The front portion of the first middle diameter portion 9b of the primary inner piston 9 is fitted in the third hole 5 of the housing 2 in a liquid-tight and slidable manner in the third hole 5 of the third cylindrical member 14. First
It is liquid-tightly and slidably fitted by the cup seal 15. The third cylindrical member 14 abuts against a cylindrical stopper 16 assembled to the front end of the small-diameter portion 9c, thereby restricting the movement of the primary inner piston 9 forward. A primary return spring 17 is contracted between the primary inner piston 9 and the third cylindrical member 14. In that case, the spring force of the primary return spring 17 is applied to the primary inner piston 9 via the third retainer 18. The primary inner piston 9 is constantly urged rearward and the third cylindrical member 14 is urged forward by the spring force of the primary return spring 17.

Further, the fourth hole 5 in the housing 2
The cylindrical member 19 is fitted and fixed in a liquid-tight manner.
The secondary piston 20 is accommodated in the inner hole and the third hole 5 of the cylindrical member 19. The secondary piston 20 has a central large-diameter portion 20a, a small-diameter portion 20b extending forward from the large-diameter portion 20a and a smaller diameter than the large-diameter portion 20a, and extending rearward from the large-diameter portion 20a and having a smaller diameter than the large-diameter portion 20a. A stepped piston is formed from a middle diameter portion 20c having a larger diameter than the small diameter portion 20b, and the large diameter portion 20a is liquid-tightly and slidably fitted in the inner periphery of the third hole 5. The small-diameter portion 20b is liquid-tightly and slidably fitted in the inner hole of the fourth cylindrical member 19 by the second cup seal 21. A secondary return spring 22 is contracted between the fourth cylindrical member 19 and the secondary piston 20, and the secondary piston 20 is constantly urged rearward by the spring force of the secondary return spring 22.
Further, the rear end of the middle diameter portion 20c of the secondary piston 20 and the front end of the third cylindrical member 14 are in contact with each other, and the secondary piston 20 and the third cylindrical member 14 move integrally in the axial direction. It has become. The retraction limit of the secondary piston 20 is restricted by the stepped portion 20d between the large diameter portion 20a and the middle diameter portion 20c abutting on the stopper 45 provided on the housing 2.

The rear end of the secondary piston 20 is formed in a cylindrical shape having an inner hole. The front end of the primary inner piston 9 and the secondary end are formed in the inner hole of the secondary piston 20 and the inner hole of the third cylindrical member 14. A first atmospheric pressure chamber 23 is formed between the second piston 2 and the rear end of the piston 20.
0, the radial hole 24 of the middle diameter portion 20c, the third cylindrical member 14
Outer diameter of the front end portion and the middle diameter portion 2 of the secondary piston 20
0c and an inner space of the third hole 5 of the housing 2, a passage hole 26 of the housing 2, and a first reservoir connection port 27, which constantly communicate with a reservoir (not shown) for storing brake fluid via an annular space 25. I have. In addition, the fourth cylindrical member 1
9, a second atmospheric pressure chamber 28 is formed between the front end of the secondary piston 20 and the housing 2 in the inner hole of the secondary piston 20. The second atmospheric pressure chamber 28 has a diameter of the front end of the fourth cylindrical member 19. It is always in communication with the reservoir via the direction groove 29, the passage hole 30 of the housing 2 and the second reservoir connection port 31.

The front end of the primary outer piston 8 and the outer peripheral step 9f of the primary inner piston 9 inside the first cylindrical member 6 and in the third hole 5 of the housing 2.
A first MCY pressure chamber 32 is formed between the first cylindrical member 14 and a rear end of the third cylindrical member 14. It is always connected to a WCY (not shown) of the first brake system via a first output port 34 formed in the housing 33. Further, a first MCY is provided at the rear end of the third cylindrical member 14.
A radial hole 35 constantly communicating with the pressure chamber 32 is formed. When the lip portion of the first cup seal 15 is located behind the radial hole 35 as shown in the figure, the radial hole 35 is Since the first MCY pressure chamber 32 communicates with the first atmospheric pressure chamber 23 through the annular space 36 between the outer peripheral surface of the small diameter portion 9 c of the piston 9 and the first MCY pressure chamber 32 through the radial hole 35 and the annular space 36. When the lip portion of the first cup seal 15 is located forward of the radial hole 35, the radial hole 35 is connected to the pressure chamber 23, that is, the reservoir.
6 and the first atmospheric pressure chamber 23, the first M
The CY pressure chamber 32 is cut off from the first atmospheric pressure chamber 23, that is, the reservoir.

On the other hand, a second MCY pressure chamber 37 is formed between the secondary piston 20 and the rear end of the fourth cylindrical member 19 inside the third hole 5 of the housing 2.
The MCY pressure chamber 37 is always connected to a WCY (not shown) of the second brake system via a second output port 38 formed in the housing 2. Further, a radial hole 39 constantly communicating with the second MCY pressure chamber 37 is formed at the rear end of the fourth cylindrical member 19.
Are drilled. When the lip portion of the second cup seal 21 is located rearward of the radial hole 39 as shown in the figure, the radial hole 39 communicates with the second atmospheric pressure chamber 28, so that the second MCY pressure chamber 37 Is connected to the second atmospheric pressure chamber 28, that is, the reservoir, through the radial hole 39,
When the lip portion of the cup seal 21 is located forward of the radial hole 39, the radial hole 39 is shut off from the second atmospheric pressure chamber 28, so that the second MCY pressure chamber 37 is shut off from the second atmospheric pressure chamber 28, that is, the reservoir. Is to be done.

A braking force control pressure chamber 40 is provided between the outer peripheral step 8 e of the primary outer piston 8 and the rear end of the second cylindrical member 7 in the inner hole of the first cylindrical member 6. And it is formed coaxially with the primary inner piston 9. This brake force control pressure chamber 40
A radial groove 41 formed at the rear end of the first cylindrical member 6;
An annular passage 42 formed between the outer peripheral surface of the first cylindrical member 6 and the inner peripheral surface of the second cylindrical member 7, the first hole 3 and the second hole 4;
Through the annular space 43 defined by the gap between the stepped portion 2c of the housing 2 and the front end of the second cylindrical member 7 at the boundary with the brake force control pressure introduction port 44 formed in the housing 2. Communicating. Brake force control pressure inlet 44
Is connected to a braking force control device (not shown). Since an example of the braking force control device will be described in detail in a fourth example described later, this first example will be described briefly with respect to this braking force control device.

That is, when the MCY pressure is generated in the first and second MCY pressure chambers 32 and 37, the braking force control device
These first and second MCY pressure chambers 32, 37 and each WC
Then, the pump is turned off and the pump of the brake force control device is operated. Then, the pump is switched between the first and second MCs.
The brake fluid in the Y pressure chambers 32 and 37 is sucked and discharged to the WCY, and a fluid pressure higher than the MCY pressure is supplied to the WCY. At this time, the braking force control device normally
An arbitrary servo ratio is set by controlling the WCY pressure according to the brake operation conditions at that time, such as when the regenerative cooperative brake is activated or when the brake assist is activated. That is, during normal brake operation, the WCY pressure is controlled so that a normal brake force corresponding to the pedaling force of the brake pedal is obtained. The WCY pressure is controlled so as to obtain a braking force, and the WCY pressure is controlled so that a braking force larger than a normal braking force is obtained during a brake assist operation.
In the MCY1 of the first example, the WCY pressure controlled by the brake force control device is supplied to the brake force control pressure chamber 40 through the brake force control pressure inlet 44.

By the way, the balance formula of the primary outer piston 8 and the primary inner piston 9 when the MCY 1 of the first example is operated is as follows. Now, W: input applied to primary inner piston 9 P _m : MCY pressure P _p : brake force control pressure of brake force control pressure chamber 40 (=
WCY pressure P _w ) A _of : sectional area of large diameter portion 8a of primary outer piston 8 (effective pressure receiving area) A _ob : sectional area of small diameter portion 8b of primary outer piston 8 (effective pressure receiving area) A _ii : primary inner piston sectional area of the first middle diameter portion 9b of 9 (effective pressure receiving area) a _io: primary cross-sectional area (effective pressure-receiving area) of the large-diameter portion 9a of the inner piston 9 F _s: the spring force of the control spring 13 F _sm: Primary_rc Spring force f ₁ of spring 17: Sliding resistance force of primary inner piston 9 by first cup seal 15 f ₂ : For liquid tightness between primary outer piston 8 and large diameter portion 9 a of primary inner piston 9. The sliding resistance force between the pistons 8 and 9 due to the seal f ₃ : the primary outer piston 8 and the first cylindrical member 6
F ₄ : sliding resistance of primary outer piston 8 due to liquid-tight seal between primary outer piston 8 and second cylindrical member 7. When the sliding resistance, the primary balance of the outer piston 8 formula _{P p × (a of -A ob} ) + F s -f 3 -f 4 + f 2 = P m × (a of -A io) (1) primary inner It becomes balance piston 9 formula _{W = P m × (a io} -A ii) + F s + F sm + f 1 + f 2 (2). Equation (1) and from _{(2), W = P m} × (A of -A ii) -P p × (A of -A ob) + F sm + f 1 + f 3 + f 4 (3) Further, the formula (1) _{more, F s = P m × (} A of -A io) -P p × (A of -A ob) + f 3 + f 4 -f 2 (4)

Based on these equations, the MCY of the first example
The pedal stroke of the brake pedal when using No. 1 will be examined. When the MCY1 is activated and the MCY pressure is generated, the brake force control device is activated. However, when the brake force control device is activated, the brake control pressure obtained by boosting the MCY pressure by the brake force control device is WCY.
, The brake control pressure (= WCY pressure P _w )
P _p > MCY pressure P _m . At this time, since (A _of −A _io ) and (A _of −A _ob ) are positive and constant in equation (4), the MC of the braking force control pressure P _p (WCY pressure P _w )
When increasing pressure for Y pressure P _m is large, the spring force F _s of the control spring 13 from the equation (4) becomes smaller, that is the amount of deflection of the control spring 13 is reduced. Conversely, when the amount of increase in the brake force control pressure P _p (WCY pressure P _w ) with respect to the MCY pressure P _m is small, the spring force F _s of the control spring 13 increases, that is, the amount of deflection of the control spring 13 increases. Become. When the amount of deflection of the control spring 13 is large, the relative movement of the primary outer piston 8 with respect to the primary inner piston 9 increases. Conversely, when the amount of deflection of the control spring 13 is small, the primary outer piston 8 Is relatively small. Thus, the magnitude of the relative movement will be changed variously according to the braking force control pressure controlled by the braking force control unit P _p (WCY pressure P _w).

Therefore, the MCY1 exhibits various braking characteristics by changing the relative movement in various ways. Now, if the relative movement is set to be smaller than the relative movement at the time of the normal brake operation, if the primary inner piston 9 linked to the brake pedal makes the same stroke as that at the time of the normal brake operation, the primary outer piston The piston 8 makes a large forward stroke by the smaller relative movement amount than when the normal brake is operated. Therefore, in this case, a larger amount of liquid is discharged than during normal brake operation. Conversely, if the relative movement is set to be larger than the relative movement during normal brake operation, the primary outer piston 8 will move when the primary inner piston 9 has the same stroke as that during normal brake operation. Strokes smaller than during normal brake operation, a smaller amount of liquid is discharged than during normal brake operation.

When this MCY1 is used in cooperation with the regenerative braking system, the pedal stroke is as follows. That is, the regenerative cooperative brake operation amount of the braking force by the regenerative braking, because it is set smaller the braking force by the WCY, WCY pressure P _w is smaller than the WCY pressure P _w in operation the normal braking. Therefore, since the relative movement of the primary outer piston 8 with respect to the primary inner piston 9 increases, at the same pedal stroke as during normal brake operation (that is, when the primary inner piston 9 is also during normal brake operation), the discharge amount of MCY1 becomes smaller. Normally smaller than when the brake is activated. When the regenerative cooperative brake is operated, the WCY pressure is set to be smaller than that during the normal brake operation as described above. As described above, the pedal stroke at the time of the regenerative cooperative brake operation can be made the same as at the time of the normal brake operation as described above.

On the other hand, when this MCY1 is used for brake assist for assisting normal brake operation, the pedal stroke is as follows. That is, at the time of the brake assist operation, the braking force by WCY is set to be increased by the assist of the braking force, so that the WCY pressure P _w
There is greater than the WCY pressure P _w during the operation normal braking.
Therefore, the relative movement of the primary outer piston 8 with respect to the primary inner piston 9 becomes small,
At the same pedal stroke as during normal brake operation, MC
The discharge amount of Y1 is larger than that during normal brake operation.
Since the WCY pressure is set to be larger during the brake assist operation than during the normal brake operation as described above, the amount of the fluid that the pump of the braking force control device sucks the brake fluid from the MCY1 side is larger than during the normal brake operation. Therefore, as described above, the pedal stroke at the time of this brake assist operation can be made the same as at the time of the normal brake operation.

As described above, in the MCY1 of the first example, even if the WCY pressure is changed by operating the brake control device for the same input, the pedal stroke can be made the same as when the normal brake is operated. become. That is, the stroke adjustment device 129 is constituted by the primary outer piston 8 and the brake force control pressure chamber 40.

In this MCY1, the input W, MCY
Since the relationship between the pressure P _m and the braking force control pressure P _p (WCY pressure P _w ) is given by the above equation (3), the input W is related to the braking force control pressure P _p (WCY pressure P _w ), When the force control pressure P _p (WCY pressure P _w ) changes, the input W also changes. Therefore, in the MCY1 of the first example, a change in pedal stroke during brake control on the WCY side can be suppressed as described above, but a change in pedal effort cannot be suppressed.

Next, the operation of the thus configured master cylinder 1 of the first example will be described. When the master cylinder 1 in which the brake pedal is not depressed is inactive, the brake booster is inactive and the secondary piston 20 abuts against the stopper 45, so that the primary outer piston 8, the primary inner piston 9, Both the one cylindrical member 14 and the secondary piston 20 are at the retreat limit in the drawing. At this time,
The first cup seal 15 is located behind the radial hole 35, the first MCY pressure chamber 32 communicates with the reservoir via the first atmospheric pressure chamber 23, and the second cup seal 21 is located behind the radial hole 39. , The second MCY pressure chamber 37 communicates with the reservoir via the second atmospheric pressure chamber 28. Further, the brake force control device is also inactive, and the pump is stopped.

When a normal brake operation is performed by depressing the brake pedal, the brake booster operates, and the brake booster generates an output boosting the pedal depression force. At this time, the output is also relatively small because the servo ratio of the brake booster is relatively small as described above. The output of the brake booster is applied to the primary inner piston 9, and the primary inner piston 9 and the primary outer piston 8 integrally move forward.

When the primary inner piston 9 moves forward and the first cup seal 15 passes through the radial hole 35 and moves forward from the radial hole 35, the first MCY pressure chamber 32 is shut off from the first atmospheric pressure chamber 23. Then, the MCY pressure is generated in the first MCY pressure chamber 32. M in the first MCY pressure chamber 32
When the third cylindrical member 14 and the secondary piston 20 integrally move forward by the CY pressure, and the second cup seal 21 passes through the radial hole 39 and moves forward from the radial hole 39, the second MCY pressure The chamber 37 is shut off from the second atmospheric pressure chamber 28, and an MCY pressure is generated in the second MCY pressure chamber 37. These first and second MCY pressure chambers 32,
Each MCY pressure 30 is a hydraulic pressure corresponding to the pedaling force or the pedal stroke, but is smaller than the hydraulic pressure necessary for generating a normal braking force because the output of the brake booster is small.

The MCY pressure in the first MCY pressure chamber 32 acts rearward on the front end of the primary outer piston 8, so that the control spring 13 bends and the primary outer piston 8 is moved relative to the primary inner piston 9. Move relatively backwards. In addition, MC
When the Y pressure is generated, the controller (not shown) operates the brake force control device, and the pump of the brake force control device sucks the brake fluid from the MCY1 and discharges the brake fluid to the WCY, thereby generating the WCY pressure. At this time, the WCY pressure is controlled to a pressure higher than the MCY pressure by the brake force control device so that a normal braking force corresponding to the pedal depression force or the pedal stroke at this time is obtained. This WCY pressure is supplied to the brake force control pressure chamber 40 through the brake force control pressure inlet 44 and acts forward on the step 8e of the primary outer piston 8. Therefore, the primary outer piston 8 has a rearward force due to the MCY pressure, a forward force due to the WCY pressure of the brake force control pressure chamber 40, a forward force due to the spring force of the control spring 13, and the primary outer piston 8 is liquid-tight. The relative movement with respect to the primary inner piston 9 is performed so that the sliding resistance force of the portion that slides is balanced. The balance equation of the primary outer piston 8 at this time is given by the above-described equation (1).

The primary inner piston 9 has a forward input (the output of the brake booster), a backward force due to the MCY pressure, a backward force due to the spring force of the control spring 13, and the primary inner piston 9 having a hydraulic force. It moves so that the sliding resistance force of the part that slides closely may be balanced. The balance equation of the primary inner piston 9 at this time is given by the above equation (2).

The braking force control pressure chamber 4
The normal brake force is obtained by the WCY pressure controlled at 0, and the normal brake operates. At this time, the relative movement between the primary outer piston 8 and the primary inner piston 9 is the same as the pedal stroke at the time of normal brake operation in the case where the above-described conventionally known brake booster having a high servo ratio is used. Is adjusted as follows.

When the depression of the brake pedal is released, the primary inner piston 9 is retracted by the spring force of the primary return spring 17 and the MCY pressure of the first MCY pressure chamber 32, and the primary outer piston 8 is released.
Also retreats integrally with the primary inner piston 9.
When the first cup seal 15 moves rearward from the radial hole 35 by the retraction of the primary inner piston 9, the first MCY pressure chamber 32 communicates with the first atmospheric pressure chamber 23 and the first MCY pressure chamber 3
The MCY pressure of 2 drops and disappears. First MCY pressure chamber 32
Of the MCY pressure of the secondary piston 20 causes the spring force of the secondary return spring 22 and the second M
It retreats due to the MCY pressure in the CY pressure chamber 37. When the secondary piston 20 is retracted, the second cup seal 21 is
9, the second MCY pressure chamber 37 communicates with the second atmospheric pressure chamber 28, so that the MCY of the second MCY pressure chamber 37
The pressure drops and disappears. With the disappearance of the MCY pressure, the brake force control device is deactivated and the pump stops. Then, the WCY pressure due to the pump discharge disappears and the fluid pressure in the brake force control pressure chamber 40 also disappears. Thereby, the primary outer piston 8 is controlled by the control spring 13.
When the first spring retainer 10 abuts on the step 9e of the primary inner piston 9, the relative movement of the primary outer piston 8 with respect to the primary inner piston 9 stops. I do. And the secondary piston 20
When the rear end abuts on the stopper 45, the primary outer piston 8, the primary inner piston 9, the third cylindrical member 14, and the secondary piston 20 are all in the illustrated retreat limit position. Thus, the first and second MCY
The pressure chambers 32 and 37 and the brake force control pressure chamber 40 are all at atmospheric pressure, the master cylinder 1 is deactivated, and the normal brake is released.

On the other hand, when the regenerative braking operation is performed, the braking force control device controls the WCY pressure to be smaller than that during the normal braking operation by the amount corresponding to the braking force generated by the regenerative braking operation. The total braking force, which is the resultant force of the braking force by the WCY pressure controlled by the braking force control device, is substantially the same as the normal braking force during normal braking operation. The pedal stroke during the regenerative braking operation is the same as the pedal stroke during the normal braking operation.

When the brake assist is operated, the WCY pressure is controlled by the brake force control device to be larger than that during the normal brake operation as described above, so that the brake force becomes larger than the normal brake force during the normal brake operation. Brake assist is performed effectively. The pedal stroke during the brake assist operation is the same as the pedal stroke during the normal brake operation.

FIG. 2 is a sectional view similar to FIG. 1, showing a second example of the embodiment of the present invention. In the following description of each example, the same reference numerals are given to the same components as those of the previous example, and the detailed description thereof will be omitted. In the above-described first example, the primary outer piston 8 is formed as a stepped piston having an outer peripheral step portion 8e. However, in the MCY1 of the second example, as shown in FIG. It has no portion 8e, and its outer periphery has the same diameter from the front end to the rear end. The primary outer piston 8 is the first cylindrical member 6
The inner peripheral surface is made liquid-tight with a metal seal 107. As shown in the figure, the metal seal 107 is provided as much as The diameter of the inner peripheral surface of the first cylindrical member 6 behind the seal 107 is larger than the inner peripheral surface of the portion of the first cylindrical member 6 where the metal seal 107 slides. Due to the enlarged diameter portion 6a, an annular gap 108 having a predetermined axial length is formed between the inner peripheral surface of the cylindrical member 6 and the outer peripheral surface of the primary outer piston 8. This gap 1
08, the brake control pressure chamber 40 and the control pressure introduction port 44 are always in communication even if the primary outer piston 8 strokes.

In the first example, the primary inner piston 9 is formed of a single member. However, the primary inner piston 9 of the second example is formed of two members, the front side member 9g and the rear side member 9h. These are screwed and connected to each other so as to be integrally movable. Furthermore, in the first example, the large-diameter portion 9a of the primary inner piston 9 is fitted to the inner periphery of the front end of the primary outer piston 8 in a liquid-tight and slidable manner. A large diameter portion 9a formed on the front side member 9g is slidably fitted to the inner periphery of the front end of the primary outer piston 8 in a liquid-tight manner (the outer periphery of the large diameter portion 9a and the inner periphery of the primary outer piston 8). Are not sealed by the cup seal as in the first example, but are sealed by appropriate sealing means.)

Further, in the second example, the first spring retainer 10 of the first example is not provided, but an annular spring retainer portion 8f is provided on the inner peripheral side of the front end portion of the primary outer piston 8 instead. The spring retainer portion 8f can contact the rear end of the large-diameter portion 8a of the front-side member 9g. Similarly, the second spring retainer 11 of the first example is not provided, but instead is formed on the rear member 9h of the primary inner piston 9 and has a larger diameter portion 9i larger than the diameter of the larger diameter portion 9a of the front member 9g.
Is provided. The control spring 13 is contracted between the step 9j formed by the large diameter portion 9i and the spring retainer 8f. Large diameter portion 9 of rear member 9h
i is slidably fitted to the inner periphery of the rear end of the primary outer piston 8 in a liquid-tight manner.

Further, the brake force control pressure chamber 40 of the first example
Is provided between the outer periphery of the primary outer piston 8 and the inner periphery of the first cylindrical member 6. In the second example, the brake force control pressure chamber 40 Between the two large diameter portions 9a and 9i of the primary inner piston 9 and the primary outer piston 8
And it is provided coaxially with the primary inner piston 9. The brake force control pressure chamber 40 is provided with a radial hole 46 of the primary outer piston 8 and the first cylindrical member 6.
Of the brake force control pressure introduction port 44 through a radial hole 47 (in the first example, the radial groove 41 in the first example) and the passage 42. Other configurations of the MCY1 of the second example are the same as those of the first example.

The balance formula of the primary outer piston 8 and the primary inner piston 9 when the MCY 1 of the second example is operated is as follows. A _ib : the cross-sectional area (effective pressure receiving area) of the large-diameter portion 9 i in the rear member 9 h of the primary inner piston 9 f ₅ : the liquid-tightness between the primary outer piston 8 and the large-diameter portion 9 i of the primary inner piston 9 When the sliding resistance of the two pistons 8 and 9 by the seal for the balance equation P _p × primary outer piston _{8 (a ib -A io) +} F s -f 3 -f 4 + f 2 + f 5 = P m × (A _of −A _io ) (5) Balance formula of primary inner piston 9 W = P _m × (A _io −A _ii ) + P _p × (A _ib −A _io ) + F _s + F _sm + f ₁ + f ₂ + f ₅ (6) From equations (5) and (6), W = _Pm × (A _of −A _ii ) + F _sm + f ₁ + f ₃ + f ₄ (7) From equation (5), F _s = P _m × (A _of −A _io ) −P _p × (A _ib −A _io ) + f ₃ + f ₄ −f ₂ −f ₅ (8)

As is clear from equation (8), also in the MCY1 of the second example, the brake force control pressure P _p (WCY pressure P _w ) controlled by the brake force control device as in the first example.
The spring force F _s of the control spring 13 is changed according to the brake force control the relative positions of the primary outer piston 8 and the primary inner piston 9 pressure P _p (WCY
It can be changed according to the pressure P _w ). Therefore, also in the brake system using the MCY1 of the second example, the pedal stroke at the time of the regenerative cooperative brake operation and the brake assist operation can be made the same as at the time of the normal brake operation as in the first example. Thus, the MCY 1 of the second example also, that is, the primary outer piston 8 and the brake force control pressure chamber 40 constitute the stroke adjusting device 129.

[0060] As apparent from the equation (7), in this MCY1 the second example, the input W is relevant only MCY pressure P _m braking force control pressure P _p (WCY pressure P _w) is Not relevant. Therefore, even when adjusting the braking force control pressure P _p (WCY pressure P _w) by the brake force control, the input W is not affected by the adjustment of the braking force control pressure P _p (WCY pressure P _w), actuated normal braking You can do the same as when. This second
The operation of the example MCY1 is the same as in the first example described above.

[0061] Thus, according to MCY1 the second example, also control the WCY pressure P _w by the regenerative coordination braking or brake assist operation, etc., the pedal stroke and the pedal force of the WCY pressure P at this time The effect of the control of _w can be prevented to make it the same as when normal braking is applied. Note that the primary outer piston 8 is
As in the example, the control pressure chamber 40 and the control pressure introduction port 44 can be always communicated with each other when the primary outer piston 8 is stroked by using a stepped piston including the large diameter portion 8a and the small diameter portion 8b. In this case, the large diameter portion 8a
And the small-diameter portion 8b as small as possible.
Even if the Y pressure changes, the influence of the change on the input is minimized. Other functions and effects of the MCY1 of the second example are the same as those of the first example.

FIG. 3 is a sectional view similar to FIG. 1, showing a third embodiment of the present invention. The first and second
In the example, both of the first and second cup seals 15,
21 are provided on the movable primary inner piston 9 and the secondary piston 20, respectively, and radial holes 35, 39 cooperating with the first and second cup seals 15, 21 are respectively formed on the fixed third piston. And in the fourth cylindrical member 14, 19, the radial direction holes 35, 39 are provided in the movable inner primary piston 9 and the secondary piston 20 in the MCY 1 of the third example, respectively. In addition, first and second cup seals 15, 21 cooperating with these radial holes 35, 39 are provided on the fixed side, respectively.

That is, in the MCY1 of the third example, the third and fourth cylindrical members 14, 19 of the MCY1 of the second example are used.
Are not provided, and instead, the fifth to seventh cylindrical members 48, 49, and 50 are fitted into the axial hole 2a of the housing 2 in this order from the front, and the first cylindrical member 6
Is fixed in the axial direction. In this case, the sixth cylindrical member 49 is fitted in the axial hole 2a in a liquid-tight manner. Then, the first cup seal 15 is disposed between the first and seventh cylindrical members 6, 50, and the second cup seal 21 is disposed between the fifth and sixth cylindrical members 48, 49. ing.

The front end of the front side member 9g of the primary inner piston 9 is formed in a cylindrical shape having an axial bore 9k,
Are formed in a bottomed cylindrical shape having an axial inner hole 20e opening forward. The radial hole 35 is formed at the front end of the front side member 9g of the primary inner piston 9 so as to communicate the outer peripheral surface with the inner peripheral surface of the inner hole 9k. The piston 20 is drilled at the front end so that the outer peripheral surface thereof communicates with the inner peripheral surface of the inner hole 20e.

The front side member 9g of the primary inner piston 9 is fitted to the first cylindrical member 6 in a liquid-tight and slidable manner, and penetrates the first cup seal 15 in a liquid-tight and slidable manner. are doing. Further, the secondary piston 20 is fitted to the sixth cylindrical member 49 in a liquid-tight and slidable manner, and penetrates the second cup seal 21 in a liquid-tight and slidable manner. Thus, the third example M
The first and second cup seals 15 and 21 are provided on the fixed side and are not provided on the pistons 9 and 20, respectively, and the CY1 is provided with only the radial holes 35 and 39 on the pistons 9 and 20, respectively. The total length of the pistons 9 and 20 can be shortened, and as a result, the mini-MCY has a short overall length.

The first atmospheric pressure chamber 23 is formed annularly between the outer peripheral surface of the first cylindrical member 6 and the inner peripheral surface of the axial hole 2a of the housing 2, and the second atmospheric pressure chamber 28 is formed. Sixth
Outer peripheral surface of cylindrical member 49 and axial hole 2a of housing 2
Is formed in an annular shape between the inner peripheral surface and the inner peripheral surface. Also, the first M
The CY pressure chamber 32 is provided inside the inner hole 9k at the front end of the front-side member 9g of the primary inner piston 9 and the seventh cylindrical member 50.
And inside the inner hole of the sixth cylindrical member 49. Further, the second MCY pressure chamber 37 is provided in the inner hole 20 e of the secondary piston 20, the inner hole of the fifth cylindrical member 48, and the axial hole 2 a of the housing 2.

In the MCY1 of the third example, when the illustrated MCY1 is not operated, the radial holes 35, 39 are located at positions rearward from the lip portions of the first and second cup seals 15, 21, respectively. . At this time, the first MCY
The pressure chamber 32 has a radial hole 35, a gap between the back surface (rear surface) of the first cup seal 15 and the first cylindrical member 6, an axial hole 51 formed in the first cylindrical member 6, and a radial hole. Atmospheric pressure is established by communicating with the first atmospheric pressure chamber 23 through the direction hole 52, and the second MCY pressure chamber 37 is
9, the second large through the gap between the back surface (rear surface) of the second cup seal 21 and the sixth cylindrical member 49, the axial hole 53 and the radial hole 54 formed in the sixth cylindrical member 49, respectively. It is in atmospheric pressure communicating with the pressure chamber 28.

Each piston 9, 20 is advanced and each radial hole 35, 39 is inserted into the first and second cup seals 15, 20, respectively.
21 is located forward of each lip, each radial hole 3
5, 39 and the respective gaps between the back surfaces of the first and first cup seals 15, 21 and the first and sixth cylindrical members 6, 49 are shut off. As a result, the first and second MCY pressure chambers 32, 37 are respectively connected to the first and second atmospheric pressure chambers 23, 2 respectively.
8, MCY pressure is generated in each of the MCY pressure chambers 32, 37. Further, the primary return spring 17 is provided between the primary inner piston 9 and the second piston 20 so as to be able to extend and contract two spring retainers 55, the maximum expansion of which is restricted.
56, and the secondary spring 22 is contracted between the second piston 20 and the housing 2 through two extendable and retractable spring retainers 57, 58 whose maximum expansion is restricted. . Other configurations of the MCY1 of the third example are the same as those of the MCY1 of the second example.

Further, the primary outer piston 8 and the primary inner piston 9 during the operation of the MCY1 of the third example
Equations (5) are the same as in the above-described second example.
And (6), so the input W is also given by equation (7) and the spring force of the control spring 13 is also given by equation (8). Furthermore, the operation of the MCY1 of the third example is different from that of the second example only in that the radial holes 35, 39 move and the first and second cup seals 15, 21 do not move. Same as two examples. The operation and effect of the MCY1 of the third example are the same as those of the second example except that the axial length of the MCY1 is shorter.

FIG. 4 is a diagram showing a brake system showing a fourth example of the embodiment of the present invention. The brake system of the fourth example is a brake system using the MCY1 of the third example. That is, in the MCY1 of the third example, the brake fluid supply passage 59 is connected to the first output port 34 of the first brake system, and the distal end side of the brake fluid supply passage 59 has two first and second brake fluids. It is branched into supply branch passages 59L and 59R. The first brake fluid supply branch passage 59L is connected to the WCY60 of the left front wheel FL, and the second brake fluid supply branch passage 59R is connected to the WCY61 of the right front wheel FR.

A normally open switching valve with a relief valve 62 is disposed in the brake fluid supply passage 59, and the switching valve with a relief valve 62 is set to the communicating position when not in operation and to the relief valve position when in operation. It is about to be. Only when the hydraulic pressure on the downstream side (WCY side) of this valve becomes equal to or higher than the relief pressure, this relief valve is switched from the downstream side of this valve to the upstream side (M
(CY side) is allowed to flow. The relief pressure of the relief valve can be changed. Furthermore, a first check valve 6 that bypasses the switching valve 62 with a relief valve and allows only the flow of the brake fluid from the upstream side to the downstream side of the switching valve 62 with a relief valve.
3 are provided.

First and second brake fluid supply branch passages 5
9L and 59R are provided with first and second pressure-intensifying valves 64 and 65, each of which is a normally open on-off valve, and bypass these pressure-increasing valves 64 and 65, respectively, to downstream of these valves. Second and third check valves 66, which allow only the flow of the brake fluid from the side to the upstream side,
67 are provided. These first and second pressure-intensifying valves 64 and 65 supply the brake fluid with WCY during antilock control (hereinafter also referred to as ABS control) as described later.
By controlling the supply to 60 and 61, pressure increase control of the WCY pressure in the ABS control is performed. Furthermore, each WC
Y60 and 61 are low-pressure accumulators 7 via first and second pressure reducing valves 68 and 69, which are normally closed on-off valves, respectively.
0 can be connected. These first and second pressure reducing valves 68 and 69 are respectively connected to the WCYs 60 and 6 during ABS control.
By controlling the discharge of the brake fluid from 1 to the low-pressure accumulator 70, the WCY pressure is reduced in the ABS control.

Further, a passage 71 connecting the branch point A of the brake fluid supply passage 59 to the brake fluid supply branch passages 59L and 59R and the low-pressure accumulator 70 has three fourth through fourth passages in this order from the branch point A side. 6 Check valve 7
2, 73, 74 are provided, and a pump 75 is provided in a passage 71 between the fourth and fifth check valves 72, 73. The pump 75 sucks the brake fluid from the passage 71 on the fifth check valve 73 side and discharges it to the passage 71 on the fourth check valve 72 side. Further, a passage 76 connecting a brake fluid supply passage 59 between the first output port 34 and the switching valve 62 and a passage 71 between the fifth and sixth check valves 73 and 74.
The passage 76 is provided with a normally closed on-off valve 77. Further, in a passage 59 between the first output port 34 and the switching valve 62, a first pressure sensor 78 for detecting the MCY pressure output from the first output port 34 is provided. 4th check valve 7
A second pressure sensor 79 is provided in a passage 71 between the WCYs 60 and 61 for detecting a hydraulic pressure which is supplied to the WCYs 60 and 61 after the pressure is increased by the pump 79 to be higher than the MCY pressure. First
Each valve 62 of the first brake system connected to the output port 34,
Each of 64, 65, 68, 69, 77 is constituted by an electromagnetic valve operated by electromagnetic force.

Connected to the second output port 38, the rear wheels RR,
In the second brake system that controls the supply and discharge of the brake fluid to each of the WCYs 80 and 81 of the RL, the same valves as the valves, pumps and pressure sensors provided in the first brake system except for the first pressure sensor 78 are provided. , A pump and a pressure sensor are provided in a similar manner. Therefore, by attaching “a” to the reference numerals of the corresponding first brake systems, detailed descriptions thereof will be omitted.

Further, both pumps 75 and 75a of the first and second brake systems are driven by one motor M82. Each pressure sensor 78, 79, 79a
Are connected to a controller (not shown) and supply detected hydraulic pressure information to the controller. Although not shown, a controller for regenerative braking, a pedal stroke sensor for brake assist, a pedal depression force sensor, an ABS controller, and wheel speed sensors for the wheels FR, FL, RR, RL are connected to the controller. Thus, information from these controllers and sensors is also input. Further, each solenoid valve and the motor M are also connected to the controller.

The controller receives information on the hydraulic pressure of each of the pressure sensors 78, 79, 79a, information on the regenerative braking operation from the regenerative braking controller, information on the pedal stroke from the pedal stroke sensor, or information on the pedal depression force from the pedal depression force sensor. , The respective operations of the switching valves 62, 62a and the opening / closing valves 77, 77a are controlled based on the normal brake operation information and the brake assist control information. That is, for example, during normal brake operation, during regenerative cooperative brake operation, or during brake assist control, the controller
a and the motor M82, that is, the pump 7
5, 75a is drive-controlled. In that case, the controller operates when the normal brake is activated, when the regenerative cooperative brake is not activated,
Alternatively, when it is determined that the WCY pressure increase control is necessary during the brake assist control, the switching valves 62 and 62a
Is switched to the relief valve position to increase the WCY pressure within the range of the relief pressure or less, and when it is determined that the reduction control of the WCY pressure is necessary during normal brake operation or regenerative cooperative brake operation, the switching valve 62 ,
62a is switched to the communication position to set the WCY pressure to M
The pressure is reduced to the CY1 side.

Further, the ABS control controller performs the normal brake operation based on the normal brake operation information based on the pedal stroke information from the pedal stroke sensor or the pedal depression force information from the pedal depression force sensor and each wheel speed information from each wheel speed sensor. When the locking tendency of the wheel is detected, the opening and closing of each pressure increasing valve 64, 65, 64a, 65a and each pressure reducing valve 68, 69, 68a, 69a are controlled so that the ABS control is performed on the wheel having the locking tendency. Has become. That is, when the ABS control controller determines that it is necessary to perform the ABS control for the wheel due to, for example, the tendency of the wheel to lock, the pressure increasing valves 64, 65,
Of the wheels 64a and 65a, the booster valve for that wheel is closed. Further, when the ABS control controller determines that the WCY pressure of the wheels having a lock tendency is required to be reduced in the ABS control, the pressure reducing valves 68, 69, 68a, 6
In 9a, the WCY pressure is reduced by opening the pressure reducing valve for the wheel and discharging the WCY pressure to the low pressure accumulators 70 and 70a. Then, when it is determined that the wheel speed of the wheel having the locking tendency has recovered and the pressure reduction control of the ABS control is unnecessary, the opened pressure reduction valve is closed. Further, when it is determined that the wheel speed of the wheel having a tendency to lock has recovered to a predetermined speed and the pressure increase control of the ABS control is necessary, the pressure increase valve for the wheel is opened again to increase the WCY pressure. In this way, the ABS control controller performs the ABS control by controlling the operations of the pressure increasing valves 64, 65, 64a, 65a and the pressure reducing valves 68, 69, 68a, 69a.

Further, the brake fluid supply branch passage 59L between the branch point A and the first pressure increasing valve 64 is connected to the brake force control pressure introduction port 44 via the brake force control pressure introduction passage 83, and the pump 75 discharge controlled WCY pressure P _w is adapted to be introduced through the braking force control pressure introduction passage 83 and the brake force control pressure inlet 44 as the brake force control pressure P _p in the brake force control pressure chamber 40 by.

In the brake system of the fourth example configured as described above, when the brake is operated, the MCY1 operates to generate the MCY pressure in the first and second MCY pressure chambers 32 and 37, respectively. At this time, since the brake booster that applies an input to MCY1 has a small servo ratio and a small output, the generated MCY pressure also has a small hydraulic pressure. These MCY pressures are output from the first and second output ports 34 and 38, respectively.

When the MCY pressure output from the first output port 34 is detected by the first pressure sensor 78 and supplied to the controller, the controller switches the switching valve 6 with a relief valve.
2, 62a is switched to the relief valve position, the normally closed on-off valves 77, 77a are opened, and the motor M82 is further driven. As a result, both pumps 75 and 75a are operated, and M
The brake fluid is sucked from CY1 through the open / close valves 77, 77a and discharged to the branch points A, Aa. The brake fluid discharged from the pumps 75 and 75a in this manner is supplied to the first and second pressure increasing valves 64 and 64a;
5a through each wheel cylinder 60, 61, 80, 81
And the brakes are activated.

Then, the controller controls the MCY pressure information from the first pressure sensor 78 and the second pressure sensors 79 and 79a.
This brake operation is usually performed based on the WCY pressure information from the controller, the regenerative cooperative brake operation information from the regenerative braking controller, the pedal stroke information from the pedal stroke sensor, or the brake assist operation information from the pedal depression force information from the pedal depression force sensor. whether it is normal) braking or a regenerative cooperative brake actuation, or to determine whether the brake assist operation, the liquid of the brake characteristic according to the determination result of the braking characteristics WCY pressure P _w is preset The switching valves 62 and 62a are switched and controlled so that the pressure is controlled. For example, if it is determined that the normal braking operation or regenerative cooperative brake actuation, the controller controls switching the switching valve 62,62a as WCY pressure P _w is controlled to the hydraulic pressure of the brake characteristics shown in FIG. 5, respectively. As a result, the braking force control is performed so that the braking force having the braking characteristic according to the above-described determination result is obtained. At this time, controlled WCY pressure P _w is introduced to the brake force control pressure chamber 40 through the braking force control pressure introduction passage 83 and the brake force control pressure inlet 44, the regenerative cooperative brake as shown in FIG. 5 In operation, the stroke of the inner piston 9, that is, the pedal stroke is controlled so as to be substantially the same as (approximate to) the pedal stroke during the normal brake operation. In the case of the brake assist operation, although not shown in FIG.
The brake characteristics are such that the Y pressure becomes larger than during normal brake operation, and the pedal stroke during brake assist operation is controlled to be substantially the same as the pedal stroke during normal brake operation.

Further, the relief pressure of the relief valves of the switching valves 62 and 62a is set to be higher than the WCY pressure controlled to the hydraulic pressure having any of the brake characteristics shown in FIG. The brake fluid discharged from the valve 75a is supplied from the relief valves of the switching valves 62 and 62a to the MCY.
There is no leakage to one side, no pressure loss, and the WCY pressure is more accurately controlled. Also, for some reason, WCY
When the pressure becomes higher than the relief pressure of the relief valve, the relief valve is opened to relieve the pressure, and the WCY pressure is controlled to be equal to or lower than the relief pressure.

Motor M82 or pumps 75, 75a
When the failure occurs, the pressure cannot be increased by the pumps 75 and 75a, and therefore, the controller holds at least the switching valve of the brake system, which cannot increase the pressure by the pump, in the communication position among the switching valves 62 and 62a. As a result, the MCY pressure generated by the advance of the primary inner piston 9 is directly supplied to the WCY, so that the brake of the brake system in which the pressure cannot be increased by the pump can be reliably operated. As shown in FIG. 5, the brake characteristic at the time of the failure is such that the WCY pressure becomes smaller than usual and the pedal stroke becomes shorter because there is no pressure increase by the pump.

In the above description of the fourth example, the brake booster is used. However, the brake booster is not always necessary and is omitted, and the primary inner piston 9 of the MCY1 is operated by the pedal depression force of the brake pedal. It can be operated directly. Further, in the fourth example, the MCY1 of the third example is used as the MCY1, but the MCY1 of the first or second example of an antidepressant may be used.

FIG. 6 is a sectional view showing a fifth example of the embodiment of the present invention. The MCY1 of the fifth example is the MC of the third example.
The following configuration is different from Y1. That is, MCY1 of the third example
Then the primary inner piston 9 is the front side member 9g
And the rear side member 9h are screwed and connected.
As shown in FIG. 6, in the MCY1 of the fifth example, the front side member 9g is formed in a cylindrical shape, and the front end of the rear side member 9h penetrates the rear end of the front side member 9g in a liquid-tight manner. And extends into the inner hole of the front side member 9g. Then, a nut 84 is screwed and fastened to the extended front-side member 9g so that the rear end of the front-side member 9g is between the nut 84 and the outer peripheral step 9m of the front-side member 9g. And the front side member 9g and the rear side member 9h are integrally connected. Other configurations of the MCY1 of the fifth example are substantially the same as those of the MCY1 of the third example.

Further, a negative pressure booster 85 is attached to the MCY1 of the fifth example as a brake booster. This negative pressure booster 85 has substantially the same configuration as a conventional general negative pressure booster. However, as described later, its servo ratio is It is set smaller.

Since the negative pressure booster 85 is almost the same as a conventional general negative pressure booster, it will be briefly described here. When the negative pressure booster 85 is in a non-operating state shown in the drawing, the valve body 87, the diaphragm power piston 88, the valve plunger 89 and the input shaft 90 are retracted by the key member 91 contacting the rear shell 92 by the spring force of the return spring 86. It is in. In this inactive state,
A first valve seat 93 formed at the rear end of the valve plunger 89 comes into contact with the valve element 94 to make an atmospheric valve 95 composed of these.
Is closed, the valve element 94 is separated from the second valve seat 96 formed in the valve body 87, and the negative pressure valve 97 made of these is opened. As a result, the variable pressure chamber 98 is connected to the first passage 99 in the valve body 87, the gap between the valve body 94 and the second valve seat 96, and the second passage 1 in the valve body 87.
The constant pressure chamber 101 communicates with the constant pressure chamber 101 through which the negative pressure is always introduced, and is shut off from the atmosphere.

When the brake pedal (not shown) is depressed from this inoperative state, the input shaft 90 moves forward.
The valve element 94 is seated on the second valve seat 96 and the negative pressure valve 97 is closed,
The variable pressure chamber 98 is shut off from the constant pressure chamber 101, the first valve seat 93 is separated from the valve body 94, the atmospheric valve 95 is opened, and the variable pressure chamber 98 communicates with the atmosphere. Then, the air inlet 102
From the inner hole 103 of the valve body 87, the first valve seat 9
3 and the valve body 94 and the first in the valve body 87.
The pressure is supplied to the variable pressure chamber 98 through the passage 99, and a pressure difference is generated between the variable pressure chamber 98 and the constant pressure chamber 101. The pressure difference causes the diaphragm power piston 98 and the valve body 87 to move forward, so that the negative pressure booster 85 outputs from the output shaft 104. With this output, MCY1
The primary inner piston 9 moves forward, and MCY1 generates MCY pressure as described above.

The reaction force generated by this output is transmitted to the brake pedal via the reaction disk 105, the valve plunger 89 and the input shaft 90, so that the driver can recognize the output of the vacuum booster 85. Then, the negative pressure booster 85
Performs servo control so that the reaction force with the input of the input shaft 90 is balanced, so that the output of the negative pressure booster 85 has a magnitude obtained by boosting the input at a preset servo ratio. This servo ratio is set smaller than the servo ratio of the conventional vacuum booster, so that the output of the vacuum booster 85 obtains the necessary normal braking force corresponding to the pedal depression force at the time of normal braking operation. Output is smaller than the output.

When the brake pedal is released, the input shaft 90
Retreats, the first valve seat 93 abuts on the valve element 94 to close the atmospheric valve 95, the valve element 94 separates from the second valve seat 96, the negative pressure valve 97 opens, and the variable pressure chamber 98 is removed from the atmosphere. It is shut off and communicates with the constant pressure chamber 101. Then, the transformer room 98
Supplied to the first passage 9 in the valve body 87.
9, the gas is discharged to the constant pressure chamber 101 through the gap between the second valve seat 96 and the valve body 94 and the second passage 100 in the valve body 87, and is further discharged from the constant pressure chamber 101 through the negative pressure inlet 106 (not shown). Discharged to pressure source. Thus, the transformation chamber 98
Becomes the same negative pressure as the constant pressure chamber 101, the pressure difference generated between the two chambers 98, 101 disappears, and the negative pressure booster 85 does not output and enters the inoperative state shown in the figure.

When a negative pressure source (pressure source), not shown, of the negative pressure booster 85 fails, the valve plunger 8 is moved forward by the input shaft 90.
9 moves forward and directly presses the output shaft 104 via the reaction disk 105. Thereby, the negative pressure booster 8
5 outputs the input of the input shaft 90 without boosting, and the primary inner piston 9 is operated by this output, so that even when the negative pressure source fails, the MCY pressure is reliably generated.

On the other hand, although not shown in FIG. 6, the MCY 1 of the fifth example is also provided with the brake system of the fourth example shown in FIG. Therefore, MCY1 of the fifth example
Generates the MCY pressure, the pumps 75 and 75a are operated in the same manner as in the brake system of the fourth example, and the WCY pressure is controlled by boosting the MCY pressure according to the normal brake operation, the regenerative cooperative brake operation, or the brake assist operation. . Then, by introducing the controlled WCY pressure into the brake force control pressure chamber 40 of the MCY1, the pedal stroke can be made the same as the pedal stroke during normal brake operation.

In the MCY 1 of the fifth example, an opening is provided so as to take out the brake force control pressure (wheel cylinder pressure) from the passage 42 connecting the brake force control pressure chamber 40 and the brake force control pressure inlet. However, this is for mounting a pressure sensor for detecting the braking force control pressure, for example, and it is needless to say that this opening is closed when it is not necessary to take out the braking force control pressure. Other configurations, other operations, and other effects of the brake system of the fifth example are the same as those of the above-described respective examples.

FIG. 7 is a sectional view showing a sixth example of the embodiment of the present invention, and FIG. 8 is a partially enlarged sectional view of the sixth example shown in FIG. In the above-described fifth example, the negative pressure booster 85 is attached to the MCY1, but in the sixth example, the hydraulic pressure booster 109 is attached to the MCY1. This hydraulic booster 109 has substantially the same configuration as a conventional general hydraulic booster, but has the same servo ratio as that of the negative pressure booster 85 of the fifth example. The servo ratio is set smaller than that of a general hydraulic booster.

Since the hydraulic booster 109 is almost the same as a conventional general hydraulic booster, it will be briefly described here. When the hydraulic pressure booster 109 is in the non-operating state shown in the drawing, the rear end of the power piston 110 is in the retreat limit by contacting the plug member 111 by the spring force of the primary return spring 17 of the MCY 1, and the front end of the input shaft 112. The cylindrical member 113 connected and fixed to the plug abuts on the plug member 111, and the input shaft 112 is at the retreat limit.
In this non-operating state, the valve element 114 provided in the power piston 110 is seated on the first valve seat 115 fixed to the power piston 110 and the second valve seat fixed to the front end of the input shaft 112. 116 is separated from the valve element 114. As a result, the power chamber 117 is
10 and is shut off from an axial hole 121 of a power piston 110 that is always in communication with a hydraulic pressure source (not shown) through a hydraulic pressure supply port 120 provided in a housing 119. A clearance between the two valve seats 116, an axial hole 122 and a radial hole 123 formed in the input shaft 112, a radial hole 124 formed in the plug member 111, and an axial direction formed in the housing 119. Hole 1
25 and hydraulic outlet 1 provided in housing 119
The reservoir 26 communicates with a reservoir (not shown). Therefore, the power chamber 117 is at atmospheric pressure.

When the brake pedal (not shown) is depressed from this inoperative state, the input shaft 112 moves forward, so that the second valve seat 116 contacts the valve element 114 and the power chamber 11
7 is blocked from the axial hole 118 and the valve body 11
4 is separated from the first valve seat 115. Then, the axial hole 1
The hydraulic pressure of the hydraulic pressure source constantly supplied to 21 is supplied to the power chamber 117 through the gap between the valve element 114 and the first valve seat 115, and the power piston 110 advances and outputs. The output of the power piston 110 causes the primary inner piston 9 of the MCY 1 to move forward, and the MCY pressure is generated as described above. On the other hand, when the hydraulic pressure in the power chamber 117 reaches a predetermined pressure, the rear end of the reaction force piston 127
12a, a reaction force is applied to the input shaft 112 from the reaction force piston 127, and a jumping action is performed. Thereafter, servo control is performed at the above-described servo ratio so that the hydraulic pressure of the power chamber 117 becomes a hydraulic pressure corresponding to the input of the input shaft 112, and the output of the power piston 110 changes the input of the input shaft 110 at this servo ratio. It will be a boosted size. As described above, this servo ratio is set to be smaller than the servo ratio of the conventional hydraulic booster, and
Is smaller than the output for obtaining the required normal braking force corresponding to the pedal depression force at that time during normal braking operation.

When the brake pedal is released, the input shaft 11
2 retracts, the valve element 114 is seated on the first valve seat 115, the second valve seat 116 is separated from the valve element 114, the power chamber 117 is shut off from the axial hole 121, and communicates with the axial direction 122. . Therefore, the hydraulic pressure in the power chamber 117 is discharged to the reservoir, and the power piston 110 moves backward. Finally, the hydraulic pressure in the power chamber 117 becomes atmospheric pressure,
The hydraulic booster 109 enters the non-operating state as shown.

When the hydraulic pressure source (pressure source) of the hydraulic pressure booster 109 has failed, the valve element 114 advances through the second valve seat 116 as the input shaft 112 advances, and contacts the power piston 110. The power piston 110 is directly pressed. As a result, the hydraulic booster 109 outputs the input of the input a-shaft 112 without boosting, and the primary inner piston 9 is operated by this output.
The CY pressure is reliably generated. MC of this 6th example
Other configurations, other operations, and other effects of the Y1 and the brake system are the same as those of the fifth example shown in FIG.

FIG. 9 is a view similar to FIG. 4, but showing a brake system according to a seventh embodiment of the present invention. In the MCY1 of each of the above-mentioned examples, each of the primary pistons is composed of two members, a primary outer piston 8 and a primary inner piston 9, which are slidably provided relative to each other. This 7th
In the MCY1 of the example, the primary piston 128 is simply formed of one member, similarly to a conventional well-known ordinary tandem master cylinder. When MCY1 is not operating,
The first and second MCY pressure chambers 32 and 37 of the MCY1 also have the first and second reservoir connection ports 2 in the same manner as the conventional ordinary MCY or the MCY1 in each of the above-described examples.
It communicates with the reservoir 135 via 7, 31.

In the MCY 1 of each of the above-described examples, the brake force control pressure chamber 4 of the stroke adjusting device 129 is provided.
0 is provided coaxially with the primary outer piston 8 and the primary inner piston 9 in the MCY 1,
In the MCY1 of the seventh example, as shown in FIG.
It is provided outside outside. That is, in the stroke adjusting device 129 of the MCY1 of the seventh example, the stroke adjusting piston 131 is provided in the housing 130. The stroke adjusting piston 131 is formed as a stepped piston composed of a large-diameter piston portion 131a formed on one side and a small-diameter piston portion 131b formed on the other side. 1
Reference numerals 31b are provided in O-rings 135 and 136 in a stepped axial hole (not given) of the housing 130 in a liquid-tight and slidable manner.

In the housing 130, an MCY pressure introducing chamber 133 is provided on the left side of the large-diameter piston portion 131a in FIG.
, A brake force control pressure chamber 40 is provided on the right side. The MCY pressure introduction chamber 133 includes an MCY pressure introduction passage 134,
It is always in communication with the first MCY pressure chamber 32 via the brake fluid supply passage 59 and the first output port 34. That is,
MCY pressure introduction MCY pressure P _m introduced into the entry 133 is adapted to act on the right in the large-diameter piston portion 131a. Further, the brake force control pressure chamber 40 is always in communication with the brake force control pressure introduction passage 83 via the brake force control pressure introduction port 44 as in the above-described respective examples. That is, the brake force control pressure P _p (WCY pressure P _w ), which is the pump discharge pressure introduced into the brake force control pressure chamber 40, acts on the small-diameter piston portion 131b to the left.

[0102] Further, the stroke adjusting piston 131 is normally urged leftward by the spring force of the control spring (corresponding to the biasing means of the present invention) 132 that is in a direction opposite to the direction of action of the MCY pressure P _m, When the MCY 1 is not operated, its left end is set at the leftmost position shown in the drawing in contact with the housing 130. Furthermore, the MCY1 of the seventh example
Is operated by a negative pressure booster 85 having a low servo ratio as in the case of the fifth example described above. That is, when the input shaft 90 strokes leftward by depressing the brake pedal 136, the negative pressure booster 8
5 is output from the output shaft 104, and the MCY
One primary piston 128 operates.

Then, as in the case of the above-described fourth example, the controller determines whether the current brake operation is a normal (normal) brake operation or a regenerative cooperative brake operation based on each information from each sensor. or, alternatively brake or the determined assist is actuated, WCY pressure P _w is preset determination result with the relief valve switching as controlled to the hydraulic pressure of the brake characteristic according to valve of the brake characteristic 62, 62a is switch-controlled. For example, when it is determined that the normal brake operation or the regenerative cooperative brake operation is performed,
Controller switching valve 62,62a as WCY pressure P _w is controlled to the hydraulic pressure of the brake characteristics shown in FIG. 5, respectively
Is switched. As a result, the braking force control is performed so that the braking force having the braking characteristic according to the above-described determination result is obtained.

[0104] At this time, the stroke adjusting device MCY pressure P _m via a first output port 34, the brake fluid supply passage 59 and the MCY pressure introduction passage 136 of the 1MCY chamber 32 1
29 is applied to the large-diameter piston portion 131a in the right direction while being introduced into the MCY pressure introduction chamber 133, and the controlled brake force control pressure P _p (WCY pressure P _w ) is applied to the brake force control pressure introduction passage 83 and the brake force control. It is introduced into the brake force control pressure chamber 40 through the pressure inlet 44 and acts on the small diameter piston portion 131b to the left. Then, the stroke adjusting piston 131 strokes to the right, the force due to MCY pressure P _m, the braking force control pressure P _p by the force, large, small-diameter piston portion 131a, the sliding resistance of the seal portion of the 131b, and the control spring 132 Stop at a position where the spring force of the balance is balanced. Then, the brake fluid of MCY1 is consumed by the stroke of the stroke adjusting piston 131 to the right.

The balance formula of the stroke adjusting piston 131 when the MCY1 of the seventh example is operated is as follows. Now, A ₁ : large diameter portion 131a of stroke adjustment piston 131
Cross-sectional area of (the effective pressure receiving area) A _2: small-diameter portion 131a of the stroke adjusting piston 131
F _s : Spring force of the control spring 132 f ₆ : Sliding resistance of the large-diameter piston 131 a of the stroke adjusting piston 131 f ₇ : Sliding of the small-diameter piston 131 b of the stroke adjusting piston 131 When _{resistance, P m × a 1 = P} p × a 2 + F s + f 6 + f 7 (9)

[0106] Equation (9) As is apparent, in MCY1 of the seventh embodiment, the same MCY pressure P _m, the brake force control pressure P _p clogging WCY pressure P _w is small, the spring force of the control spring 132 F _s is increased, i.e. the stroke is increased to the right of the stroke adjusting piston 131, also is large WCY pressure P _w, the spring force F _s of the control spring 132 is reduced, i.e. the right of the stroke adjusting piston 131 The stroke to the direction becomes small.
In other words, the stroke adjustment device 129 of this embodiment, the same MCY pressure P _m, when WCY pressure P _w is small, blur MCY1 - is controlled so consumption of gas and liquid is increased, WCY pressure P _w is When it is larger, control is performed so that the consumption of the brake fluid of MCY1 becomes smaller.

[0107] On the other hand, during non-operation of the regeneration brake, that is, during the normal braking operation, WCY pressure P _w pump 75,75a is actuated, a predetermined normal braking force is controlled to a large hydraulic pressure so as to obtain. At the time of the normal brake operation, a large servo ratio can be obtained by operating the pump. Although pumps 75,75a during operation of the regenerative brake is boosted is WCY pressure P _w operates similarly, by the amount of braking force by the regenerative brake this time, WCY pressure P _w is in during operation normal braking is controlled to the WCY pressure P _w is less than fluid pressure. At the time of the regenerative cooperative braking operation, a small servo ratio can be obtained by operating the pump.

[0108] Then, the brake fluid consumption WCY60,61,80,81 because WCY pressure P _w is increased during the normal braking operation is increased, in this case WCY pressure P
_{Since w} becomes large, the consumption of the brake fluid of MCY1 by the stroke adjusting device 129 is relatively small, so that the brake fluid consumption as a whole is a predetermined amount set in advance. Also, when the regenerative braking is activated, the WC
Since the Y pressure P _w becomes smaller, the brake fluid consumption of the WCYs 60, 61, 80, and 81 becomes smaller.
Since the pressure P _w decreases, the stroke adjusting device 12
9, the brake fluid consumption of the MCY1 is relatively large, so that the brake fluid consumption as a whole is substantially the same as the brake fluid consumption during the normal brake operation described above.
Therefore, the stroke of the primary piston 128 of the MCY 1 during the regenerative braking operation, that is, the pedal stroke of the brake pedal 136 is substantially the same as (approximately) the stroke during the normal brake operation, and the pedal stroke is the normal brake operation. There is almost no change between the operation and the regenerative cooperative brake operation.

In the case of the brake assist operation, FIG.
Although not shown, the WCY pressure is controlled to be larger than that during normal brake operation, and the pedal stroke during brake assist operation is controlled to be substantially the same as the pedal stroke during normal brake operation. The housing 130 of the stroke adjusting device 129 of the seventh example is also used as the housing 2 of the MCY 1, that is, the stroke control device 129 is located at the position where the stroke adjusting piston 131 is displaced from the central axis of the primary piston 128 in the housing 2 of the MCY 1. It can also be provided as follows. Other configurations of the MCY1 and the brake system of the seventh example are the same as those of the fourth example.

According to the stroke control device 129 of the seventh example configured as described above, the following operation and effect can be obtained as compared with the above-described examples. That is, in each of the above-described examples, the primary outer piston 8 is affected by the _three sliding resistances f ₂ , f ₃ , and f ₄ as apparent from the equation (4), or is apparent from the equation (8). Is affected by the _four sliding resistances f ₂ , f ₃ , f ₄ , f _5.
In Y1, the operation of the stroke adjusting piston 131 is influenced only by the two sliding resistances f ₆ and f ₇ as is apparent from the equation (9). Therefore, in the stroke adjusting device 129 of the seventh example, the sliding resistance is reduced as compared with each of the above-described examples. Also improve.

The stroke adjusting device 1 of the seventh example
29 is provided outside the MCY1 at a position deviated from the central axis of the primary piston 128, so that the structure is compared with the stroke adjusting device 129 of each of the above-described examples provided coaxially with the primary inner piston 9 inside the MCY1. Can be simplified, the assemblability can be improved, and the cost can be reduced. Other operations of the MCY1 and the brake system of the seventh example, and other operations and effects of the stroke adjusting device 129 of the seventh example are the same as those of the fourth example. In the seventh example, the negative pressure booster 8 is used as the brake booster.
5, the hydraulic booster 109 described above can be used, and the brake booster can be omitted.

FIGS. 10A and 10B respectively show:
It is sectional drawing which shows the stroke adjustment apparatus 129 of the 8th-10th example of embodiment of this invention. In the stroke adjusting device 129 of the seventh example described above, two O-rings 135, 13
6. The stroke adjusting piston 131 and the housing 130
1 is liquid-tight between the inner peripheral surface of the axial hole of FIG.
As shown in FIG. 0 (a), in the stroke adjusting device 129 of the eighth example, the metal seal 137 is provided between the large and small diameter piston portions 131a and 131b of the stroke adjusting piston 131 and the inner peripheral surface of the axial hole of the housing 130. , 138 are liquid-tight. In the eighth example, the spring 132 is contracted between the steps of the large and small diameter piston portions 131a and 131b and the housing 130.

According to the stroke adjusting device 129 of the eighth example, the sliding resistance can be greatly reduced and the number of parts can be reduced as compared with the O-rings 135 and 136 of the seventh example. However, in the stroke adjusting device 129 of the eighth example,
Since the liquid tightness is worse than that of the seventh example, it is necessary to machine the sliding surfaces of the axial holes of the housing 130 and the sliding surfaces of the large and small diameter piston portions 131a and 131b with high surface accuracy in order to improve the liquid tightness. There is. Other configurations and other operational effects of the stroke adjusting device 129 of the eighth example are the same as those of the seventh example. Is the same.

As shown in FIG. 10B, in the stroke adjusting device 129 of the ninth example, the stroke adjusting piston 13
A seal ring 139 such as a Teflon (registered trademark) seal provided on the large and small diameter piston portions 131a, 131b is provided between the large and small diameter piston portions 131a, 131b and the inner peripheral surfaces of the axial holes of the housing 130. , 140 to make it liquid-tight. According to the stroke adjusting device 129 of the ninth example, the metal seals 137 and 13 of the eighth example are used.
Although the liquid tightness is improved as compared with No. 8, the sliding resistance cannot be made smaller than in the eighth example. Stroke adjusting device 1 of the ninth example
The other configurations and other effects of the 29 are the same as those of the eighth example, and the configurations of the MCY1 of the ninth example and the other configurations and the effects of the brake system are the same as those of the eighth example.

As shown in FIG. 10C, in the stroke adjusting device 129 of the tenth example, the stroke adjusting piston 1
31 between the large and small diameter piston portions 131a, 131b and the inner peripheral surfaces of the axial holes of the housing 130 are liquid-tight by rubber cup seals 141, 142 provided in the large and small diameter piston portions 131a, 131b, respectively. It has been. According to the stroke adjusting device 129 of the tenth example, the liquid tightness is improved as compared with the seal rings 139 and 140 of the ninth example, but the sliding resistance cannot be made smaller than that of the ninth example. Other configurations and other operational effects of the stroke adjusting device 129 of the tenth example are the same as those of the ninth example.
The configuration of the MCY1 of the tenth example and the other configuration and operation and effect of the brake system are the same as those of the ninth example.

FIG. 11 is a sectional view showing a stroke adjusting device 129 according to an eleventh embodiment of the present invention. In the stroke adjusting device 129 of the seventh example, the braking force control pressure P _p (WCY pressure P _w ) is applied to the small diameter piston portion 131b of the stroke adjusting piston 131.
As shown in FIG. 1, the stroke adjusting device 12 of the eleventh example
9, the brake force control pressure P _p is applied to the step portions of the large and small diameter piston portions 131a and 131b of the stroke adjusting piston 131.
Is acting. That is, the braking force control pressure chamber 40
Are formed in an annular shape by being surrounded by the step, the outer periphery of the small-diameter piston portion 131b, and the housing 130.

In the above-described seventh to tenth examples, the two leak locations to the reservoir are the large-diameter piston portion 131a and the small-diameter piston portion 131b of the stroke adjusting piston 131. Stroke adjusting device 1
29 is one of the small-diameter piston portions 131b, so that the liquid tightness is improved. Other configurations and other operational effects of the stroke adjusting device 129 of the eleventh example are the same as those of the eighth example, and the other configurations and operational effects of the configuration of the MCY1 and the brake system of the eleventh example are the same as those of the eighth example. Is the same.

FIG. 12 is a sectional view showing a twelfth example of the stroke adjusting device 129 according to the embodiment of the present invention. The stroke adjusting device 12 of the eighth example shown in FIG.
9, the stroke adjusting piston 131 is
In the stroke adjusting device 129 of the twelfth example, a cylinder member 143 separate from the housing 130 is fitted into the axial hole of the housing 130. , This cylinder member 1
The large and small diameter piston portions 131a and 131b of the stroke adjusting piston 131 are provided in the axial hole 43 in a liquid-tight and slidable manner, respectively.

In the stroke adjusting device 129 of the twelfth example configured as described above, the portion in which the stroke adjusting piston 131 slides is formed by the cylinder member 143 different from the housing 130. Processing of the surface can be performed more accurately and more easily. Therefore, the stroke adjusting device 129 of the twelfth example is advantageous in terms of workability and cost.
This is superior to the three stroke adjusting devices 129. Other configurations and other operational effects of the stroke adjusting device 129 of the twelfth example are the same as those of the eighth example, and the other configurations and operational effects of the configuration of the MCY1 and the brake system of the twelfth example are the same as those of the eighth example. Is the same.

FIG. 13 is a sectional view showing a thirteenth example of the stroke adjusting device 129 according to the embodiment of the present invention. In the twelfth example, the stroke adjustment piston 131 is large,
The small-diameter piston portions 131a and 131b are both slidably provided in the cylinder member 143 fitted in the axial hole of the housing 130 in a liquid-tight and slidable manner. As shown in FIG. 13, the large-diameter piston portion 131 of the stroke adjusting piston 131
a is provided in a cylinder member 143 fitted in the axial hole of the housing 130 in a liquid-tight and slidable manner, and the small-diameter piston portion 131b of the stroke adjusting piston 131 is liquid-tight in the axial hole of the housing 130. And slidably provided.

In the eleventh and twelfth examples described above,
The large and small diameter piston portions 131a and 131b are
The gap between the outer peripheral surface and the inner peripheral surface on which the outer peripheral surface slides is sealed with a metal seal. In the thirteenth example, the outer peripheral surface of the large-diameter piston portion 131a is formed inside the axial hole of the cylinder member 143. The outer peripheral surface of the small-diameter piston portion 131b and the inner peripheral surface of the axial hole of the housing 130 are sealed by a cup seal 144 which is an elastic seal. The metal seal and the cup seal 144 define the brake force control pressure chamber 40.

Further, in the above-described eleventh example, the spring 13
2 is connected to a reservoir 135. In this thirteenth example, a spring chamber 145 containing a spring 132 is in communication with the atmosphere. Further, in the spring chamber 145, the spring receiving member 14 is provided.
The performance of the stroke adjusting device 129 can be arbitrarily changed only by changing the spring 132 and the spring receiving member 146.

In the stroke adjusting device 129 of the thirteenth example configured as described above, the small-diameter piston 13
1b and the inner peripheral surface of the axial hole of the housing 130 are sealed by the cup seal 144, so that the brake force control pressure chamber 40 is more reliably compared to a case where the gap is sealed with a metal seal. Can be prevented from leaking. Therefore, in the in-line system in which the brake fluid in the first MCY pressure chamber 32 is supplied to the brake force control pressure chamber 40, when the brake fluid in the brake force control pressure chamber 40 leaks, the brake fluid in the first MCY pressure chamber 32 is reduced accordingly. Although a large amount of fuel is consumed, it is possible to prevent the leakage of the fluid in the brake force control pressure chamber 40 in this way, thereby suppressing the consumption of the brake fluid in the first MCY pressure chamber 32, and increasing the stroke of the primary piston 9 of the MCY1, that is, the pedal stroke. The increase can be prevented.

Further, the stroke adjusting device 12 of the thirteenth example
In No. 9, although the sliding resistance of the stroke adjusting piston 131 is slightly increased by the cup seal 144, the sliding resistance is small as compared with the case where the stroke adjusting piston 131 is incorporated in the MCY1 because the number of cup seals is small. Other configurations and other operational effects of the stroke adjusting device 129 of the thirteenth example are the same as those of the eleventh example, and the other configurations, operational effects of the MCY1 of the thirteenth example and the brake system are the same as those of the eighth example. Is the same.

FIG. 14 is a sectional view showing a stroke adjusting device 129 according to a fourteenth embodiment of the present invention. In the above-described thirteenth example, the small-diameter piston portion 131b of the stroke adjusting piston 131 is provided only in the axial hole of the housing 130 in a liquid-tight and slidable manner.
In the example stroke adjusting device 129, the small-diameter piston portion 131b is provided in the axial hole of the housing 130 and the cylinder member 143 in a liquid-tight and slidable manner.

Further, in the above-described thirteenth example, the small-diameter piston portion 131b has the housing
In the stroke adjusting device 129 of the fourteenth example, the small-diameter piston portion 13
1b is sealed by a cup seal 144 in the axial hole of the housing 130 and is sealed by a metal seal 145 in the axial hole of the cylinder member 143. In the fourteenth example, the metal seal and the metal seal 145 of the large-diameter piston portion 131a are used to control the braking force control pressure chamber 4.
0 is defined.

In the stroke adjusting device 129 of the fourteenth example configured as described above, the metal seal 145
The liquid in the brake force control pressure chamber 40 leaking from the chamber acts on the cup seal 144. However, the liquid pressure of the liquid acting on the cup seal 144 passes through the metal seal 145, so that it is smaller than that of the thirteenth example. Therefore, the sliding resistance of the stroke adjusting piston 131 due to the cup seal 144 can be reduced. The other configurations and other operational effects of the stroke adjusting device 129 of the fourteenth example are the same as those of the thirteenth example. Is the same.

FIG. 15 is a sectional view similar to FIG. 4, showing a fifteenth embodiment of the present invention. Similarly to the above-described respective examples, the MCY1 and the brake system of the fifteenth example also discharge the brake fluid in the first MCY pressure chamber 32 by a pump, and the pump discharge pressure is controlled by a pressure control valve according to a pedal depression force or a pedal stroke. An in-line system that controls and supplies the controlled pump discharge pressure to the brake force control pressure chamber 40 in the MCY1 and the wheel cylinders 60 and 61 is adopted.

The MCY1 of the fifteenth example will be specifically described. As shown in FIG. 15, the MCY1 of the fifteenth example corresponds to the MCY1 of the third example shown in FIG. 4 in place of the primary outer piston 9 of the MCY1. Cylindrical primary piston 9
Are slidably provided in the axial hole of the housing 2 in a liquid-tight manner. Further, the input shaft 112 of the MCY 1 of the sixth example shown in FIG. 7 is fitted into the axial hole of the primary piston 9 from the outside of the housing 2 so as to be liquid-tight and relatively movable. The same control spring 13 as in the third example is contracted between the primary piston 9 and the input shaft 112.

The first atmospheric pressure chamber 23 formed between the primary piston 9 and the secondary piston 20 has a small-diameter hole 9n of the primary piston 9, an axial hole 122 formed in the input shaft 112, and a radial hole 123. , The reservoir 13 through the space 124 between the primary piston 9 and the plug member 111 and the passage hole 125 of the housing 2.
5 (shown in FIG. 9).

The brake force control pressure chamber 40 of the fifteenth example
Is formed between the inner peripheral surface of the primary piston 9 in the axial direction and the outer peripheral surface of the input shaft 112 in front of the input shaft 112. The brake force control pressure chamber 40 is always in communication with the brake force control pressure inlet 44 via a radial hole 33 formed in the primary piston 9 and an annular recess 55.

Then, in the MCY1 of the fifteenth example,
The input W and the spring force of the control spring 13 act on the input shaft 112 in the same direction, and the wheel cylinder pressure P _W
Acts on the input shaft 112 so as to oppose the input W and the spring force of the control spring 13. Then, the force due to the wheel cylinder pressure P _W and the input shaft 11
The wheel cylinder pressure P _W is controlled so that the sliding resistance of No. 2 and the input W and the spring force of the control spring 13 are balanced. Other configurations of the MCY1 and the brake system of the fifteenth example are the same as those of the fourth example shown in FIG.

The balance equation of the input shaft 112 when the MCY1 of the fifteenth example is operated is as follows. W: input applied to the input shaft 112 P _m : MCY pressure in the first MCY pressure chamber 32 P _p : hydraulic pressure in the brake force control pressure chamber 40 (pump discharge pressure =
WCY pressure P _W ) A ₃ : Input shaft 112 for receiving pump discharge pressure P _p
The large diameter portion 112a and the pressure receiving area of the primary piston 9 A _4: pressure-receiving area of the primary piston 10 to the pressure receiving a MCY pressure P _m F _s1: set load F _s2 control spring 13: the first return spring 17 of the primary piston 10 K ₁ : spring constant of the control spring 13 L: relative movement amount between the primary piston 9 and the input shaft 112 f ₈ : sliding resistance of the input shaft 112 f ₉ : sliding resistance of the primary piston 9 The balance type of 112 is the pump discharge pressure P
_Since the force acting on the input shaft 112 of _p and the sliding resistance f ₈ of the input shaft 112 are controlled so as to be balanced with the input W and the spring force of the control spring 13 (F _s1 + K ₁ · L), W = P _p · A ₃ − (F _s1 + K ₁ · L) + f ₈ (10) From equation (10), L = (P _p · A ₃ −W−F _s1 + f ₈ ) / K ₁ (11) P _p = ( W + F _s1 + K ₁ · L−f ₈ ) / A ₃ (12) The balance formula of the primary piston 9 is
Force acting on the primary piston 9 of the pump discharge pressure P _p is the force acting on the primary piston 9 of the master cylinder pressure P _m, the spring force of the control spring 13 (F _s1 + K ₁ ·
L), since is controlled to balance the sliding resistance f ₉ of the spring force F _s2 and primary piston 9 of the first return spring _{17, P p · A 3 =} P m · A 4 + F s1 + K 1 · L + F _s2 + f ₉ is (13). Further, according to the equations (12) and (13), P _m · A ₄ = W−F _s1 −f ₈ −f ₉ (14)

As is apparent from the equation (11), as the pump discharge pressure _Pp, that is, the pressure _PW increases, the relative movement amount L increases as in the above-described respective examples.
(Amount corresponding relative movement amount L in accordance with the pump discharge pressure) becomes smaller than the stroke of the primary piston 9 in accordance with the stroke pump discharge pressure P _p of 12. Then, since the relative movement amount L increases as the pump discharge pressure P _p is large,
After all, as the pump discharge pressure P _p is large, shortening the amount of stroke S _i of the input shaft 112 increases.

Accordingly, pedal stroke control during normal brake operation and regenerative cooperative brake operation is as follows. That is, during normal brake operation, the regenerative brake is not operated and the wheel cylinder pressure _Pw is controlled so as to increase, that is, the pump discharge pressure _Pp
Is controlled to be large, the amount of shortening of the stroke of the input shaft 112 is increased, and the stroke of the input shaft 112 is effectively shortened. Therefore, the pedal stroke is effectively shortened during normal brake operation.

[0136] Further, since the regenerative cooperative brake during operation are controlled pump discharge pressure P _p is smaller wheel cylinder pressure P _w is reduced, the braking forces by pump discharge pressure P _p only minute the braking force by the regenerative braking smaller Is controlled so that At this time, each wheel cylinder 60, 6
1; 80 and 81 brake fluids are 1st and 2nd M respectively
Because they are returned to the CY pressure chambers 32 and 37,
The strokes of the primary piston 9 and the secondary piston 20 are reduced. However, since the pump discharge pressure _Pp is small, the stroke of the input shaft 112 is small, so that the pedal stroke at the time of the regenerative cooperative brake operation is substantially the same as at the time of the normal brake operation. As described above, the pedal stroke is substantially the same between the normal brake operation and the regenerative cooperative brake operation, and is substantially the same.

As is apparent from the equation (14), M
Since CY pressure P _m is determined by the input W of the input shaft 112, the pedaling force is not changed even if changing a wheel cylinder pressure P _w during normal braking operation and the regenerative coordination braking.
Thus, also in the MCY1 of the fifteenth example, the vehicle deceleration (that is, the braking force) and the pedal stroke with respect to the pedaling force become substantially constant regardless of whether the regenerative cooperative brake is operated.

During normal brake operation, since the wheel cylinder pressure _PW is controlled to be relatively large and the pump discharge pressure _Pp is controlled to be large, as described above, the pedal stroke is relatively greatly reduced and reduced. Become.

On the other hand, during the regenerative braking operation, the controller controls the first pressure-intensifying valve 64 by PWM control.
Just as much as the braking force from the regenerative braking,
The pump discharge pressure P _P and the wheel cylinder pressure P _W is controlled to be smaller than in the normal braking operation. As a result, each wheel cylinder 60, 6
1; the braking forces generated by 80 and 81 also decrease accordingly. Thus, the entire braking force during regenerative cooperative braking operation is the resultant force of the regenerative braking force and the MCY pressure P _M braking force by, the whole during the regenerative cooperative brake operation braking force of the normal braking operation of the above It is almost the same as the braking force. At this time, since the MCY pressure P _M as described above is determined by the input W of the input shaft 112, the pedaling force is not changed even if changing the wheel cylinder pressure P _W is. In addition, the pedal stroke when the regenerative cooperative brake is activated is substantially the same as the pedal stroke when the normal brake is activated.

From the above, the master syringe of the fifteenth example is described.
The pedal depression force-MCY pressure characteristic in
During operation, relatively large MCY pressure P_mOccurs
Then, as shown by the solid line in FIG.
Relatively large MCY pressure P _mCharacteristics, and
When the regenerative cooperative brake is activated, the pressure control valve 47
Relatively small MCY pressure is generated by delaying switching setting
In some cases, the same pedal effort is applied as shown by the dotted line in the figure.
And relatively small MCY pressure P_mCharacteristic.

Therefore, the total braking force with respect to the pedal depression force shown in FIG. 16C is as shown by a solid line in FIG. At this time, the braking force due to the pump discharge pressure in the entire braking force is a portion obtained by subtracting the braking force due to the output of the brake booster from the total braking force during the normal braking operation. This is a portion obtained by subtracting the braking force due to the output of the brake booster and the braking force due to the regenerative cooperative braking operation from the braking force (part partitioned by a dotted line).
That is, during the regenerative cooperative braking operation, the braking force due to the pump discharge pressure is smaller by the amount of the braking force due to the regenerative cooperative braking operation than during the normal braking operation.

On the other hand, the pedaling force-pedal stroke characteristic of the brake pressure increasing master cylinder 1 of the fifteenth example is as follows.
During normal brake operation, the pedal stroke is greatly reduced as the stroke of the primary piston 10 increases, so that the characteristic has a relatively gentle gradient as shown by the solid line in FIG. Sometimes the MCY pressure is low and the primary piston 10
Is small, but the stroke is corrected so that the amount of shortening of the pedal stroke with respect to the stroke of the primary piston 10 is reduced, so that the stroke at the time of the normal brake operation is substantially the same as shown by the dotted line in FIG. The characteristic has a relatively gentle gradient. As described above, the pedaling force-pedal stroke characteristic is almost the same between the normal brake operation and the regenerative cooperative brake operation, and is almost the same. Other operations and other effects of the fifteenth example are substantially the same as those of the fourth example shown in FIG.

As the brake booster, another booster other than the negative pressure booster 85 and the hydraulic booster 109 described above can be used. Also, as the brake system, a brake system other than the fourth example can be used. Further, in each of the above-described examples, the master cylinder piston is composed of two members, the primary outer piston 8 and the primary inner piston 9. The present invention can be applied to any type in which the stroke of the master cylinder piston is sometimes controlled by the wheel cylinder pressure to make the stroke equal to the stroke during normal brake operation.

Further, in each of the above examples, a tandem type master cylinder is used, but the present invention can also be applied to a single type master cylinder having one master cylinder piston. Further, the MC of the present invention may be applied to other brake operations other than the regenerative cooperative brake operation or the brake assist operation, for example, an engine brake operation.
Y can be applied.

[0145]

As is apparent from the above description, according to the master cylinder of the present invention, the stroke of the master cylinder piston is adjusted when the wheel cylinder pressure changes by the stroke adjusting device that is controlled by the wheel cylinder pressure. become able to. Therefore, even if the wheel cylinder pressure changes variously due to, for example, the normal brake operation, the regenerative cooperative brake operation, or the brake assist operation, the stroke of the master cylinder piston remains the same as the stroke during the normal brake operation. can do.

In particular, according to the present invention, when the wheel cylinder pressure changes, not only the stroke of the master cylinder piston can be made equal to the stroke at the time of normal brake operation, The input applied to the cylinder piston can be kept unchanged even if the wheel cylinder pressure changes. Therefore, the master cylinder according to the invention of claim 4 can be suitably used for various brake operations.

Further, according to each of the seventh to twelfth aspects of the invention, since the stroke adjusting device is provided at a position off the center axis of the primary piston of the master cylinder, the structures of the master cylinder and the stroke adjusting device can be simplified. It is possible to improve the assemblability and reduce the cost. In addition, since the structure can be simplified, the position of the sliding resistance of the stroke adjusting device can be reduced, so that the accuracy of the stroke control by the stroke adjusting device can be further improved.

According to the thirteenth aspect of the present invention, when the pump fails, the master cylinder pressure is directly supplied to the wheel cylinders.
The brake can be operated by the master cylinder pressure. Further, according to the fourteenth aspect, the servo ratio of the brake booster can be set smaller than the servo ratio for the normal brake operation, so that a smaller brake booster can be adopted.

Further, according to the invention of claim 15, when the pressure source of the brake booster fails, the brake booster outputs the operating force of the brake operation without boosting. The master cylinder piston can be operated by the output of the brake booster. Therefore, even when the pressure source fails, the master cylinder pressure can be reliably generated in the master cylinder pressure chamber.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a master cylinder in a first example of an embodiment of the master cylinder according to the present invention.

FIG. 2 is a sectional view showing a master cylinder according to a second example of the embodiment of the present invention.

FIG. 3 is a sectional view showing a master cylinder according to a third embodiment of the present invention.

FIG. 4 is a view showing a fourth example of the embodiment of the present invention, and showing a brake system using the master cylinder of the third example of the present invention shown in FIG.

FIG. 5 is a diagram showing brake characteristics in various brake operations.

6 is a cross-sectional view showing a fifth example of the embodiment of the present invention, which is almost the same as the master cylinder of the third example of the present invention shown in FIG. 3, and showing a master cylinder combined with a negative pressure booster. is there.

FIG. 7 is a sectional view showing a sixth example of the embodiment of the present invention, which is the same as the master cylinder of the fifth example of the present invention shown in FIG. 6 and which is combined with a hydraulic booster. .

FIG. 8 is a partially enlarged sectional view of a sixth example shown in FIG. 7;

FIG. 9 is a view similar to FIG. 4, showing a brake system according to a seventh embodiment of the present invention.

FIGS. 10A and 10B are respectively a stroke adjusting device 1 according to an eighth and a tenth example of the embodiment of the present invention;
FIG.

FIG. 11 is a sectional view showing a stroke adjusting device 129 according to an eleventh example of an embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a twelfth example of a stroke adjusting device 129 according to an embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a thirteenth example of the stroke adjusting device 129 according to the embodiment of the present invention.

FIG. 14 is a cross-sectional view showing a stroke adjusting device 129 according to a fourteenth example of the embodiment of the present invention.

FIG. 15 shows a fifteenth example of the embodiment of the present invention.
It is sectional drawing similar to.

16A and 16B show brake characteristics of the brake pressure increasing master cylinder shown in FIG. 15; FIG.
A diagram showing the Y pressure characteristic, (b) is a diagram showing the braking force,
(C) is a diagram showing a pedal depression force, and (d) is a diagram showing a pedal stroke characteristic with respect to a pedal depression force.

[Explanation of symbols]

1: Master cylinder (MCY), 2: Housing, 6:
First cylindrical member, 7: second cylindrical member, 8: primary outer piston, 9: primary inner piston, 13
... Control spring, 14 ... third cylindrical member, 15 ... First
Cup seal, 17 ... primary return spring,
19: fourth cylindrical member, 20: secondary piston, 2
DESCRIPTION OF SYMBOLS 1 ... 2nd cup seal, 22 ... Secondary return spring, 23 ... 1st atmospheric pressure chamber, 27 ... 1st reservoir connection port, 28 ... 2nd atmospheric pressure chamber, 31 ... 2nd reservoir connection port,
32: first MCY pressure chamber, 34: first output port, 35: radial hole, 37: second MCY pressure chamber, 38: second output port, 39
... radial holes, 40 ... brake force control pressure chamber, 44 ... brake force control pressure inlet, 59 ... brake fluid supply passage, 60,
61, 80, 81 ... wheel cylinder (WCY), 62,
62a: switching valve with relief valve, 64, 64a: first pressure increasing valve, 65, 65a: second pressure increasing valve, 68, 68a: first pressure reducing valve, 69, 69a: second pressure reducing valve, 75, 75a: pump,
77, 77a: on-off valve, 78: first pressure sensor, 79, 7
9a: second pressure sensor, 83: brake force control pressure introduction passage, 85: negative pressure booster, 109: hydraulic booster, 12
9: Stroke adjusting device, 131: Stroke adjusting piston, 132: Control spring, 144: Cup seal, 145: Metal seal

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Shimada 2-11-6 Shinmeicho, Higashimatsuyama-shi, Saitama Bosch Brake System Co., Ltd. (72) Inventor Satoru Watanabe 2--11 Shinmeicho, Higashimatsuyama-shi, Saitama No. 6 Inside the Bosch Brake System Co., Ltd. (72) Inventor Hiroaki Niino 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Denso Co., Ltd. (72) Kazuya Maki 1-1-1, Showa-cho, Kariya-shi, Aichi (72) Inventor Mamoru Sawada 1-1-1, Showa-cho, Kariya-shi, Aichi F-term (reference) 3D048 BB07 BB25 BB27 CC08 CC26 CC54 HH15 HH18 HH26 HH42 HH54 HH55 HH66 HH75 RR06 RR11 RR25 RR35

Claims (15)

[Claims] 1. A master cylinder having a master cylinder piston for generating a master cylinder pressure in a master cylinder pressure chamber, wherein the master cylinder pressure can be supplied to a wheel cylinder. A stroke of the master cylinder piston is controlled by a wheel cylinder pressure controlled by discharging the brake fluid to the wheel cylinder. 2. A stroke adjusting device for a master cylinder according to claim 1, wherein said stroke adjusting device is provided coaxially with said master cylinder piston in said master cylinder. 3. The master cylinder piston includes a first piston that is stroked by the input and a second piston that is provided on the first piston so as to be liquid-tight and relatively slidable.
A stroke of the first piston is adjusted by applying the wheel cylinder pressure to the second piston and sliding the second piston relative to the first piston. The master cylinder stroke adjusting device according to claim 2. 4. The second piston is formed in a cylindrical shape having an outer peripheral step portion, and slides in a liquid-tight manner in an axial hole of the housing or an inner hole of a cylindrical member fixed to the housing. Movably fitted, the first piston is fitted in the second piston in a liquid-tight and relatively slidable manner, and the outer peripheral step of the second piston and the outer periphery of the second piston A brake force control pressure chamber formed between the inner periphery of the axial hole of the housing or the inner periphery of the inner hole of the cylindrical member, and into which the wheel cylinder pressure is introduced; 4. The stroke adjustment of the master cylinder according to claim 3, wherein the stroke of the first piston is adjusted by causing the wheel cylinder pressure introduced into the chamber to act on the outer peripheral step of the second piston. Location. 5. The second piston is formed in a cylindrical shape having an inner peripheral step, and the first piston is fitted in the second piston in a liquid-tight manner and relatively slidably. A brake force control pressure chamber formed between an inner periphery of the second piston and an outer periphery of the first piston by an inner peripheral step portion of the second piston, and into which the wheel cylinder pressure is introduced; 4. The master according to claim 3, wherein the stroke of the first piston is adjusted by causing the wheel cylinder pressure introduced into the brake force control pressure chamber to act on an inner peripheral step of the second piston. Cylinder stroke adjustment device. 6. An input shaft which is stroked by an input by a brake operation force is provided so as to be relatively movable with respect to the master cylinder piston, and an input shaft of the input shaft is provided between the input shaft and the master cylinder piston. A control spring for controlling a stroke is contracted. The input and the spring force of the control spring act on the input shaft in the same direction, and the wheel cylinder pressure applies the input and the control spring to the input shaft. The wheel cylinder pressure is controlled so that the force by the wheel cylinder pressure and the spring force of the input and control springs are balanced. The master cylinder stroke adjusting device according to claim 2. 7. The master cylinder stroke adjusting device according to claim 1, wherein the stroke adjusting device is provided at a position deviated from a center axis of the master cylinder piston. 8. A stroke adjusting piston for adjusting a stroke of the master cylinder piston, the master cylinder pressure acting on the stroke adjusting piston in one direction, and the wheel cylinder pressure being opposed to the master cylinder pressure. The stroke adjusting device for the master cylinder according to claim 7, wherein the stroke of the master cylinder piston is adjusted by causing the stroke adjusting piston to perform the stroke by acting in a direction in which the master cylinder piston moves. 9. The stroke adjustment piston has one side formed in a large-diameter piston section and the other side formed in a small-diameter piston section, and the master cylinder pressure is applied to the large-diameter piston section. 9. The stroke adjusting device for a master cylinder according to claim 8, wherein the wheel cylinder pressure acts on the small-diameter piston portion. 10. The stroke adjusting piston has one side formed in a large-diameter piston section and the other side formed in a small-diameter piston section, and the master cylinder pressure is applied to the large-diameter piston section. 9. A stroke adjusting device for a master cylinder according to claim 8, wherein said wheel cylinder pressure acts on a step between said large diameter piston portion and said small diameter piston portion. 11. A biasing means for biasing the stroke adjusting piston in a direction opposite to a direction in which the master cylinder pressure acts, wherein a force caused by the master cylinder pressure is applied to the force caused by the wheel cylinder pressure and the force applied by the wheel cylinder pressure. 11. The stroke adjusting device for a master cylinder according to claim 8, wherein the wheel cylinder pressure is controlled so as to balance the urging force of the urging means. 12. A method according to claim 9, wherein said large diameter piston portion is sealed with a metal seal, and said small diameter piston portion is sealed with at least one of a metal seal and an elastic seal. A master cylinder stroke adjusting device according to any one of the preceding claims. 13. The master cylinder stroke adjustment according to claim 1, wherein the master cylinder pressure is supplied to the wheel cylinder when the pump fails. apparatus. 14. The input is applied to the master piston by the output of a brake booster that boosts the operating force of the brake operation with a pressure of a pressure source at a predetermined servo ratio and outputs the boosted force. 14. The master cylinder stroke adjusting device according to claim 1, wherein the servo ratio is set smaller than a servo ratio for normal brake operation. 15. The master cylinder stroke adjusting device according to claim 14, wherein the brake booster outputs the operating force of the brake operation without boosting when the pressure source fails.