JPH03132456A - Brake control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention controls brake fluid pressure by acting on a master cylinder so as to obtain an optimal deceleration in response to a brake input. The present invention relates to a brake control device for separately enabling braking action.

(Prior art) In the case of vehicle brakes, it is important to check whether the relationship between the amount of depression of the brake pedal (brake input) and the deceleration of the vehicle is always the same, whether it is preferable for brake operation, changes in payload, disc Due to wear of the pads of a braking device such as a brake, the deceleration changes for the same amount of depression of the brake pedal, and the same correspondence is not always obtained. Therefore, a torque control device for solving this problem has been proposed in Japanese Patent Laid-Open No. 1118746/1983.

As shown in FIG. 6, this device includes a booster 4 for assisting an output shaft 3 acting on a master cylinder 2 in response to an input from an input shaft l, and a control for controlling the assistance of the output shaft 3. It consists of a valve 5.

The booster 4 divides the inside of the housing 6 into two chambers, a constant pressure chamber 9 and a variable pressure chamber 10, by a power piston 8 equipped with a diaphragm 7, and connects an input shaft l to a cylindrical guide member II fixed to the power piston 8. or connected plunger 12
is slidably inserted into the output shaft 3 in front of the plunger 12.
is arranged. The tip of the output shaft 3 is fitted into and held by the input piston 13 of the master cylinder 2. Further, the constant pressure chamber 9 is connected to a negative pressure generation source such as an intake pipe (not shown) of the engine, and is always in a negative pressure state.

To explain the control valve 5, there is a Hartz chamber 1 inside.
Solenoids 16 and 17 are arranged on both sides of the Hartz chamber 14 in a housing 15 that defines a housing 15, and a boat 19 is connected to a piping 18 communicating with the constant pressure chamber 9, and a variable pressure chamber IO is connected to the valve chamber 14. A boat 21 to which the piping 20 communicating with is connected and a boat 22 to introduce the atmosphere are open. A poppet valve 23 is provided in the valve chamber 14 to open and close the boat 19 and the boat 21 in communication with each other. Further, a valve 25 for opening and closing communication between the boat 21 and the boat 22 is formed in the rod 24 which is activated by energizing the solenoids 16 and 17.

Based on the signal from the brake input detection sensor 26 provided on the input shaft l and the signal from the deceleration detection sensor 27 that detects the deceleration of the vehicle from the rotational speed of the wheels, the control device 28 appropriately controls the solenoid 16. .17 is energized.

According to this configuration, as shown by the shaded range in FIG. 7, a lower limit deceleration region I and an upper deceleration region ■ are set with a predetermined width with respect to the ideal deceleration according to the amount of depression of the brake pedal. However, it is possible to control the deceleration so that it falls within that range.

To explain this specifically, when the brake is inactive, the constant pressure chamber 9 and the variable pressure chamber 10 as shown in FIG.
The two are connected to each other and are in a negative pressure state. When a brake is operated, the output shaft 3 or the master cylinder 2 is acted upon in response to input from the input shaft 1, and brake fluid pressure is supplied to the wheel cylinder of a brake device such as a disc brake, thereby decelerating the vehicle. During this deceleration, if the deceleration is below the above-mentioned area tool, the solenoids 16 and 17 are energized to move the lot 24, close the poppet valve 23, and cut off communication between the constant pressure chamber 9 and the variable pressure chamber 10. The valve 25 is opened to introduce atmospheric air from the boat 22 into the variable pressure chamber 10. Then, the pressure difference between the constant pressure chamber 9 and the variable pressure chamber 10 increases, and the power piston 8 assists the output shaft 3. Then, when the deceleration enters region 1, solenoid 16.1
The deceleration is maintained within region I by controlling the energization to 7 and closing the valve 25 to stop introducing the atmosphere.

On the other hand, when the power piston 8 moves forward due to the pressure difference between the constant pressure chamber 9 and the variable pressure chamber 10 and assists the output shaft 3, when the deceleration exceeds the area 2, both solenoids 1
6. Appropriately control the energization to 17 to maintain constant pressure chamber 9 and variable pressure chamber lO.
By communicating with the two, the pressure difference is reduced and the support is reduced.

Then, when it enters the deceleration area ■, the poppet valve 2
3 to stop the introduction of negative pressure, the deceleration is maintained within the range.

In this way, by appropriately supplying negative pressure or atmospheric air to the variable pressure chamber 10, it is possible to always achieve an ideal deceleration depending on the amount of depression of the brake pedal.

In addition to the above, by operating the control valve 5 regardless of the operation of the input shaft 1, it is possible to maintain the braking force applied when the vehicle is stopped on a slope, etc., or to suddenly start or accelerate the vehicle. Sometimes it is used as a hydraulic pressure source for traction control to prevent drive wheels from slipping.

(Problems to be Solved by the Invention) However, the conventional brake control device described above has the following problems.

If there is a break in the electrical circuit that energizes the solenoid 16, 17, and it is no longer possible to energize the solenoid 15, 17 and operate the canopy rod 24, the bobbet valve 23 will be open, resulting in constant pressure. The room 9 and the pressure change room 10 are communicated with each other. Since both lO and O are in a negative pressure state, the output shaft 3 cannot be assisted using the pressure difference, and only the thrust from the input shaft 1 due to the pedal effort is applied to the output shaft 3, which is an ideal reduction for the brake input. The problem was that not only would it not be possible to obtain sufficient speed, but there was also a risk that sufficient braking force would not be available.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a brake control device that can assist the output shaft even when the electric circuit is damaged.

(Means for Solving the Problems) The brake control device of the present invention has a power supply that divides the inside of the housing into two chambers: a constant pressure chamber in a negative pressure state and a variable pressure chamber into which negative pressure or atmospheric air is introduced. a booster comprising a piston, a cylinder filled with pressure fluid on the constant pressure chamber side of the housing, and a piston that slides on the cylinder according to movement of the power piston; A valve mechanism is provided for introducing negative pressure or atmospheric air into the variable pressure chamber in response to movement of an input shaft connected to the
an assisting operation section provided with a piston operated by pressure fluid supplied from the cylinder of the booster to assist the output shaft acting on the master cylinder; and an assisting operation section provided between the variable pressure chamber and the valve mechanism, and provided with An electromagnetic switching valve that always communicates between the variable pressure chamber and the valve mechanism when no power is supplied, cuts off communication between the variable pressure chamber and the valve mechanism when current is supplied, and introduces negative pressure or atmospheric air into the variable pressure chamber. It is characterized by

(Function) With this configuration, negative pressure or atmosphere is supplied to the booster's transformation chamber by the valve mechanism by movement of the input shaft, or negative pressure or atmosphere is supplied to the booster's transformation chamber by switching the solenoid switching valve. The power piston moves due to the pressure difference between the variable pressure chamber and the constant pressure chamber, and the pressure fluid in the piston or cylinder provided in the power piston is supplied and discharged to the assisting operation section, and the piston of the assisting operation section moves. do. As a result, the force that the output shaft acts on the master cylinder in response to the brake input from the input shaft can be increased or decreased, or the output shaft can act on the master cylinder to generate brake fluid pressure regardless of the brake input from the input shaft. It can be increased or decreased.

In addition, even if the electromagnetic switching valve does not operate due to a break in the electric circuit, etc., the valve mechanism of the auxiliary operation part and the transformer chamber of the booster are connected, so that the negative impact from the auxiliary operation part to the transformer chamber, which is a normal function, will be removed. Pressure or atmospheric supply control is performed without reducing the braking force.

(Example) Next, an example of the present invention will be described based on the drawings. Note that FIG. 1 is a schematic diagram showing the overall configuration of this embodiment, and FIG.
The figure is a diagram showing the configuration of the assisting control section used in FIG. 1.

The brake control device 29 of this embodiment includes a booster 31 that supplies pressure fluid to an assist operation section 30 based on a brake input from a brake pedal, which is a brake operation section, and an output shaft 32 using the pressure fluid supplied from the booster 31. and an assist operation unit 30 that assists the booster 31 by introducing negative pressure or atmospheric air into the booster 31 regardless of brake input.
The support control section 33 is generally configured to control the operation of the support control section 33.

First, the configuration of the booster 31 will be explained.

The inside of the housing 34 is divided into two chambers, a constant pressure chamber 37 and a variable pressure chamber 38, by a power piston 36 equipped with a diaphragm 35. The constant pressure chamber 37 is divided into two chambers, a constant pressure chamber 37 and a variable pressure chamber 38. P and piping 3
9 and is always in a negative pressure state.

Further, the variable pressure chamber 38 is connected to the assisting operation section 30 by a pipe 40 via an assisting control section 33, which will be described later, and negative pressure or atmospheric air is introduced into the variable pressure chamber 38. A piston 42 is provided on the constant pressure chamber 37 side of the power piston 36 and is slidable in a cylinder 41 provided in the housing 34 and filled with pressure fluid. The power piston 36 is urged by a return spring 43 in a direction in which the volume of the variable pressure chamber 3B is reduced (to the right in the figure).

Next, the assistance operation section 30 will be explained.

The housing 44 has a stepped cylinder 45 inside, a valve body 46 is slidably fitted into the cylinder 45, and the inside of the housing 45 is divided into a front chamber 47 and a rear chamber 48. . The front chamber 47 is connected to the negative pressure generation source P by a pipe 49 and is always in a negative pressure state, and the rear chamber 48 is connected to the variable pressure chamber 38 of the booster 3 by a pipe 40. A plunger 51 to which an input shaft 50 is connected is slidably fitted into the valve body 46, and relative movement between the plunger 51 and the valve body 46 is regulated within a certain range by a key 52. ing. The rear side (right side in the figure) of the valve body 46 is a cylindrical part 53.
The inside of the cylindrical portion 53 communicates with the front chamber 47 through a passage 54, and with the rear chamber 48 through a passage 55.

A poppet valve 56 is provided inside the cylindrical portion 53 , and the poppet valve 56 has a valve seat 57 formed on the plunger 51 and a valve body 46 .
The variable pressure chamber 3 of the booster 3 is moved in response to the movement of the input shaft 50.
Valve mechanism 59 for controlling the introduction of negative pressure or atmosphere to 8
It consists of That is, the valve seat 57 of the plunger 51 is seated and the valve seat 58 of the valve body 46 is seated.
Since the rear chamber 48 communicates with the front chamber 47 via the passage 54 when the booster 31 is not seated, negative pressure can be supplied to the pressure transformation chamber 38 of the booster 31, and the plunger 51
When the poppet valve 5 is separated from the valve seat 57 of the valve body 46 and is seated on the valve seat 58 of the valve body 46, the poppet valve 5
Since the rear chamber 48 and the atmosphere are communicated through the gap on the inner peripheral side of the booster 31, the atmosphere can be supplied to the variable pressure chamber 38 of the booster 31.

A recess 60 that opens toward the front (leftward in the drawing) is formed in the part body 46, and the front end surface of the plunger 51 faces the recess 60. Further, a flange portion 62 on the rear end side of the output shaft 32 is slidably fitted into the recess 60 via a reaction disk 61, and the tip of the output shaft 32 abuts the input piston 64 of the master cylinder 63. ing.

A piston 65 that slides on the cylinder 45 is formed in the front part of the valve body 46, and the piston 65 has a piston part 6G that slides on the large diameter part of the cylinder 45 and a piston part 67 that slides on the small diameter part. consisting of each piston portion 66.
A cylinder chamber 68 is configured between the cylinder chambers 67 and 67 .
8 is connected to the inside of the cylinder 41 provided in the booster 31 by a pipe 69. And cylinder chamber 6
By supplying pressure fluid into the piston part 66
．． The part body 46 is advanced by the difference in pressure receiving area 67. Note that 70 is a return spring that urges the part body 46 rearward.

Next, the assistance control section 33 will be explained.

The assisting control unit 33 includes an electromagnetic switching valve 71 provided in the middle of the piping 40 connecting the pressure transformation chamber 38 of the booster 31 and the rear chamber 48 of the assisting operation unit 30, and a control device 72 that controls the electromagnetic switching valve 71. It is composed of.

As shown in FIG. 2, the electromagnetic switching valve 71 is a combination of two electromagnetic three-boat two-position switching valves 73, 74 and an electromagnetic two-boat two-position switching valve 75 in series. One boat 7 of the first 3-bot 2-position switching valve 73
6 is connected to the front chamber 47 of the assisting operation section 30 by a pipe 77, and one boat 78 of the second three-bottom two-position switching valve 74 communicates with the atmosphere. In addition, the left side in FIG. 2 is connected to the variable voltage chamber 38, and the right side is connected to the rear chamber 48.

Under normal conditions, each electromagnetic switching valve 73, 74, 75 is in the
As shown in FIG. 3, 4, and 2, the pressure changing chamber 38 and the rear chamber 48 are in communication with each other because they are located at the positions of ■, ■, and ■, respectively. and a first three-bottom two-position switching valve 7;
3 is excited and switched to the @ position, the communication between the rear chamber 48 of the assist operation section 30 and the voltage transformation chamber 38 of the booster 31 is cut off, and negative pressure is supplied from the front chamber 47 to the voltage transformation chamber 38, returning to the normal state. When the second three-bottom, two-position switching valve 74 is energized and switched to the (2) position, communication between the rear chamber 48 and the variable pressure chamber 38 is cut off, and atmospheric air is supplied to the variable pressure chamber 38. Also, when the 2-point 2-position switching valve 75 is excited and switched to ■, the transformation chamber 3
8 and the rear chamber 48 is cut off.

The control device 72 is provided on the input shaft 50 and receives signals from a brake input detection sensor 79 that detects depression of a brake pedal and a deceleration detection sensor 80 that detects vehicle deceleration from the number of rotations of the wheels. The electromagnetic switching valve 71 is controlled so that the deceleration is as high as possible. Further, the electromagnetic switching valve 71 can also be controlled in response to a signal for performing traction control or hill hold.

5. The operation of the brake control device 72 having the above configuration will be explained.

When the brake fluid pressure lever (not shown) is depressed to move the input shaft 50 forward, the poppet valve 56 leaves the valve seat 57 of the plunger 51 and seats on the valve seat 58 of the valve body 46, so that the atmosphere is sucked into the assist operation section 30. is introduced into the rear chamber 48 and further supplied to the variable pressure chamber 38 of the booster 31 through the piping 40. Therefore, booster 3
1, a pressure difference occurs between the constant pressure chamber 37 in a negative pressure state and the variable pressure chamber 38 into which the atmosphere is introduced, the power piston 36 moves forward, and the piston 42 pushes out the pressure fluid in the cylinder 41.

Then, the pressure fluid flows into the cylinder chamber 68 of the assisting operation section 30.
When the piston 65 moves forward, it assists the output shaft 32 and acts on the master cylinder 63 with a large force. As a result, high hydraulic pressure is supplied to wheel cylinders such as disc brakes provided on the wheels, thereby braking the vehicle. At this time, the input from the input shaft 50 and the output from the output shaft 32 have a relationship as shown in FIG. 4.

Here, the relationship between the ideal deceleration and the input from the input shaft 50 is shown by the solid line F in FIG.

In this figure, for example, if the deceleration A relative to the brake input is smaller than the ideal value, the output from the output shaft 32 will be small and the brake fluid pressure supplied to the wheel cylinders will be low, so as shown in Fig. 4. Input F. The output for f. You can increase the brake fluid pressure by increasing it from f□. Therefore, the control device 72 of the assistance control section 33 controls the electromagnetic switching valve 71 based on the signals from the respective sensors 79 and 80. By switching the second 2-position 3-boat electromagnetic switching valve 74 of the electromagnetic switching valve 71 to the ■ position, communication between the rear chamber 48 of the assisting operation section 30 and the transformation chamber 38 is cut off, and the atmosphere is allowed to flow into the transformation chamber. 38, the output shaft 32 is assisted by a large force.

In addition, as shown at point B in FIG. 5, if the deceleration relative to the brake input is larger than the ideal value,
3 control device 72 controls the first two positions 3 of the electromagnetic switching valve 71.
By controlling the boat electromagnetic switching valve 73 and switching it to the ■ position, communication between the rear chamber 48 of the assisting operation section 30 and the pressure transformation chamber 38 is cut off, and negative pressure is supplied from the front chamber 47 to the pressure transformation chamber 38 . This reduces the assistance to the output shaft 32.

In this way, the assistance of the output shaft 32 can be controlled so that an ideal damping force is always obtained with respect to the brake input.

If the electric circuit is disconnected, the control device 72 of the assistance control section 33 cannot give instructions to the electromagnetic switching valve 71;
Since the variable pressure chamber 38 is in communication with the valve mechanism 59 that responds to the brake input from the input shaft 50,
Negative pressure or atmospheric air can be introduced by switching between the two, and the normal assisting action is carried out, so the braking force is not reduced.

In addition, in this embodiment, traction control and high-reflex folding can be performed.

In traction control, when the vehicle is accelerating, it is determined that the wheels are likely to slip based on detection data from an acceleration sensor, a sensor that detects the rotational speed of the wheels, etc.
When the determination signal C is input to the control device 72 of the assist control unit 33, the second 3-bot 2-position electromagnetic switching valve 74 is switched to supply atmospheric air to the pressure conversion chamber 38, thereby controlling the input shaft 50. Regardless of the input from the booster 31, pressure fluid is supplied to the cylinder chamber 68 of the assist operation section 30, the piston 65 of the assist operation section 30 moves, and thereby the output shaft 32 acts on the master cylinder 53. It generates brake fluid pressure and applies appropriate braking force to the wheels to prevent slipping.

In addition, in hill hold, when the assist control unit 33 receives a signal to perform hill hold while the brake pedal is depressed to brake the vehicle, the 2-bot 2-position electromagnetic switching valve 75 switches. By cutting off the communication between the rear chamber 48 and the variable pressure chamber 38 and maintaining the atmosphere within the variable pressure chamber 38, the braking force is prevented from being released.

In this way, brake fluid pressure can be generated regardless of the brake input force from the input shaft 50.
Various controls can be performed.

Next, another embodiment of the assistance control section 33 will be described based on FIG. 3.

This is the electromagnetic switching valve 71 of the assistance control section 33 in the above embodiment.
Instead, a control valve 8I shown in FIG. 3 is used.

The configuration of this control valve 81 will be explained.

The interior is divided into two chambers 84 and 85 by a diaphragm 83 provided in the input slot 82. One chamber 84 is connected to the rear chamber 48 of the assisting operation section 30, and the other chamber 85 is connected to the variable pressure chamber 38 of the booster 31. A communication passage 86 that communicates both chambers 84 and 85 is formed in the input rod 82, and a poppet valve 87 is opposed to the portion where the communication passage 86 opens into the other chamber 85, and the input rod 82 is moved. Then, communication path 8
6 is shut off by a poppet valve 87, and the other chamber 85 is communicated with the outside. A rod 90 of a plunger 89 that moves when the proportional solenoid 88 is energized is in contact with the inlet trot 82 .

In the control valve 81 having this configuration, when the normal proportional solenoid 88 is not energized, the rear chamber 48 of the assisting operation section 30 and the variable voltage chamber 38 of the booster 31 are in communication with each other, so that the input shaft 50 Negative pressure or atmospheric air is introduced into the variable pressure chamber 38 in accordance with the operation of the valve mechanism 59 based on input from the variable pressure chamber 38 . If the deceleration relative to the brake input is smaller than the ideal value, a signal from the control device 72 causes the proportional solenoid 8 of the control valve 81 to
8 is energized. This causes the rod 90 of the plunger 89 to
By pushing the input rod 82, the communication passage 86 is shut off by the poppet valve 87, and the atmosphere is supplied to the variable pressure chamber 38 via the other chamber 85. In this way,
As in the above embodiment, the output shaft 32 is assisted to increase the braking force and achieve ideal deceleration.

In addition, in the embodiment using this control valve 81, when the deceleration is smaller than the ideal value, the output shaft 32 can be further assisted to increase the deceleration.
Since it does not act to reduce deceleration, the piping 77 is not required in the above embodiment.

In this control valve 81 as well, if the electric circuit is disconnected, the control device 72 may no longer be able to give instructions, or the rear chamber 48 of the assisting operation section 30 and the variable pressure chamber 38 are in a state of communication. Negative pressure or atmospheric air can be introduced into the variable pressure chamber 38 by switching the Hartz mechanism 59 of the assisting operation section 30, and the normal assisting action is performed, so that the braking force is not reduced.

(Effects of the Invention) As described in detail above, the present invention provides a method for supplying negative pressure or atmospheric air to the transformer chamber of the booster using the valve mechanism of the assisting operation section, and supplying negative pressure or atmospheric air to the transformer chamber by switching the electromagnetic switching valve. By supplying brake fluid pressure from the master cylinder, the brake fluid pressure can be generated and increased or decreased freely. As a result, it is possible to maintain a constant correspondence between brake input and deceleration even if changes in the vehicle's payload or wear of the brake butt occur. control is also possible.

Furthermore, even if the electric circuit is disconnected, normal brake operation can be performed, so the braking force does not decrease and the vehicle can be braked stably.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the brake control device of the present invention, FIG. 2 is a circuit diagram showing an example of the electromagnetic switching valve shown in FIG. 1, and FIG. 3 is a schematic diagram showing an example of the electromagnetic switching valve shown in FIG. Fig. 4 is a diagram showing the relationship between the input and output of the device shown in Fig. 1, and Fig. 5 is a diagram showing the relationship between the input and deceleration of the device shown in Fig. 1. FIG. 6 is a vertical cross-sectional view showing an example of a conventional brake control device, and FIG. FIG. 30... Assist operation section 31... Booster 32.
... Output shaft 33 ... Assistance control section 34 ...
Housing 36... Power piston 37...
Constant pressure chamber 38... Variable pressure chamber 41... Cylinder 42... Piston 50... Input shaft
59... Valve mechanism 63... Master cylinder 6
5... Piston 71... Solenoid switching valve

Claims (1)

[Claims] (1) The housing is provided with a power piston that divides the inside of the housing into two chambers: a constant pressure chamber in a negative pressure state and a variable pressure chamber into which negative pressure or atmospheric air is introduced, and a pressure fluid is provided on the constant pressure chamber side of the housing. a booster comprising a filled cylinder, the power piston being provided with a piston that slides on the cylinder in response to movement of the power piston; and a booster comprising a piston that slides in the cylinder in response to movement of the power piston; and A valve mechanism is provided to introduce negative pressure or atmospheric air into the
an assisting operation section provided with a piston operated by pressure fluid supplied from the cylinder of the booster to assist the output shaft acting on the master cylinder; and an assisting operation section provided between the variable pressure chamber and the valve mechanism, and provided with An electromagnetic switching valve that always communicates between the variable pressure chamber and the valve mechanism when no power is supplied, cuts off communication between the variable pressure chamber and the valve mechanism when current is supplied, and introduces negative pressure or atmospheric air into the variable pressure chamber. A brake control device featuring: