JP2014162318A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device using a pump and capable of securing pressure-rise responsive property even at low temperature without addition of any new members.SOLUTION: A piston pump includes: a first sucking-in process for discharging brake fluid in a discharge chamber via a discharge valve in association with going motion and also sucking the brake fluid into a sucking-in chamber by inflating the sucking-in chamber; and a second sucking-in process for sucking the brake fluid sucked into the sucking-in chamber in association with return motion and brake fluid from a second fluid passage.

Description

  The present invention relates to a brake device.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. This document discloses a feed ring that is a cup seal attached so as to be movable relative to the piston of a piston pump, and the feed ring pressurizes liquid in the feed chamber and pumps it to the pump chamber during the intake stroke. Has been. As a result, the pressurization response of the pump is ensured even at a low temperature when the liquid becomes highly viscous.

JP 2008-208788 A

However, in the technique disclosed in the technique described in Patent Document 1, the number of parts is increased because the feed ring is provided, and the feed ring needs to be processed with high accuracy. .
The present invention has been made paying attention to the above-mentioned problem, and is to provide a brake device using a pump capable of ensuring boosting response even at low temperatures while suppressing an increase in cost.

  In order to achieve the above object, in the present invention, the piston pump discharges brake fluid, which is compressed in the discharge chamber in accordance with the forward movement, to the master cylinder side through the discharge valve, and expands the suction chamber to expand the suction chamber. A first suction step for sucking the brake fluid, and a second suction step for sucking the brake fluid sucked into the suction chamber and the brake fluid from the second fluid passage into the discharge chamber in the backward movement.

  According to the present invention, it is possible to suppress a decrease in discharge capability while suppressing an increase in cost and increasing a suction resistance.

FIG. 2 is a hydraulic circuit diagram of the brake hydraulic pressure control device according to the first embodiment. It is an axial sectional view of the piston pump of Example 1. 2 is an axial cross-sectional view illustrating configurations of a check valve and a reservoir of Example 1. FIG. FIG. 3 is an axial sectional view of the check valve according to the first embodiment. It is a perspective view of the filter member of the check valve of Example 1. It is a brake fluid pressure circuit of a 12 valve brake fluid pressure device. It is an axial sectional view of a gate-in valve. It is an axial sectional view of a gate-in valve. It is the schematic of the piston pump of Example 1. FIG.

[Example 1]
[Configuration of brake hydraulic circuit]
FIG. 1 is a hydraulic circuit diagram of the brake hydraulic pressure control device 32 according to the first embodiment. The brake fluid pressure control device 32 according to the first embodiment includes ten valves on the fluid pressure circuit. The hydraulic circuit is formed in a housing 33 provided between the master cylinder M / C and the wheel cylinder W / C. The housing 33 is cut out from an aluminum block and has a substantially rectangular parallelepiped shape. A plurality of liquid passages and the like are formed in the housing 33, and each valve, pump unit, and motor described later are provided.
This brake fluid pressure control device 32 is a required fluid pressure from the controller such as Vehicle Dynamics Control (VDC: Vehicle Behavior Control), Anti-lock Brake System (ABS), Brake Assist (BA). The hydraulic pressure is controlled according to

The brake fluid pressure control device 32 has an X piping structure composed of two systems of a P system brake fluid pressure circuit 21P and an S system brake fluid pressure circuit 21S. Hereinafter, “P” is added to the reference numerals of the component members provided in the P system, and “S” is added to the reference numerals of the component members provided in the S system. The symbols “P” and “S” are not attached. Similarly, “FL” is assigned to the component member provided corresponding to the left front wheel, “FR” is assigned to the component member provided corresponding to the right front wheel, and the component member provided corresponding to the left rear wheel. "RL" is attached to the reference numeral, and "RR" is attached to the constituent parts provided corresponding to the right rear wheel. , “RL” and “RR” are not attached.
The left front wheel cylinder W / CFL and the right rear wheel wheel cylinder W / CRR are connected to the P system, and the right front wheel wheel cylinder W / CFR and the left rear wheel wheel cylinder W are connected to the P system. / CRL is connected. Each wheel cylinder W / C is connected to the housing 33 at wheel cylinder ports 19RL, 19FR, 19Fl, 19RR. The master cylinder M / C is connected to the housing 33 at master cylinder ports 20P and 20S. Master cylinder M / C and wheel cylinder W / C are connected by liquid passages 12P and 12S. A piston pump PP is provided in the P system hydraulic circuit, and a piston pump PS is provided in the S system hydraulic circuit. These piston pumps PP and PS are driven by a single motor M.

The master cylinder M / C and the suction side of the pump P are connected by liquid passages 10P and 10S. On the liquid path 10, reservoirs 8P and 8S having check valves 7P and 7S are provided. The master cylinder side of the check valve 7 of the liquid path 10 is described as liquid paths 10aP and 10aS, and the pump P side of the reservoir 8 is described as liquid paths 10bP and 10bS. The liquid passage 10b is provided with check valves 23P and 23S. The check valve 23 is opened with respect to the flow of brake fluid from the reservoir 8 toward the pump P, and is closed with respect to the flow in the reverse direction. It is like that.
Master cylinder M / C and wheel cylinder W / C are connected by liquid passages 12P and 12S. On the liquid path 12, gate-out valves 2P and 2S, which are normally open valves, are provided. Check valves 15P and 15S are provided in the fluid passages 17P and 17S that bypass the gate-out valve 2, and the check valve 15 detects the flow of brake fluid from the master cylinder M / C toward the wheel cylinder W / C. On the other hand, the valve is opened and closed against a reverse flow.

Pressure increase valves 3FL, 3FR, 3RL, and 3RR, which are normally open valves, are provided on the liquid passage 12 and between the gate-out valve 2 and each wheel cylinder W / C. Check valves 9FL, 9FR, 9RL, 9RR are provided in the liquid passages 16FL, 16FR, 16RL, 16RR that bypass each pressure increasing valve 3, and this check valve 9 is changed from the wheel cylinder W / C to the master cylinder M / C. The valve opens with respect to the flow of the brake fluid toward the side, and closes with respect to the flow in the reverse direction. The wheel cylinder W / C and the reservoir 8 are connected by liquid passages 13P and 13S. On the liquid path 13, pressure reducing valves 4FL, 4FR, 4RL, 4RR, which are normally closed on / off valves, are provided.
The discharge side of the piston pump P and the liquid path 12 are connected by liquid paths 11P and 11S. The liquid passage 11 is connected between the gate-out valve 2 and the pressure increasing valve 3 in the liquid passage 12. The fluid path 11 is provided with check valves 6P and 6S. The check valve 6 is opened for the flow of brake fluid from the pump P toward the fluid path 12, and is closed for the flow in the reverse direction. It is supposed to be.

  Here, the operation of the check valve 7 provided adjacent to the reservoir 8 will be described. During normal braking, that is, when each valve, pump, etc. are not operating, if brake fluid pressure is generated in the master cylinder M / C, the check valve 7 is closed and the master cylinder M / C and the reservoir 8 are shut off. . Then, the brake fluid is supplied to each wheel cylinder W / C through the fluid passage 12. Next, at the time of ABS operation, when the pressure increasing valve 3 is closed and the pressure reducing valve 4 is opened as an initial operation, the brake fluid in the wheel cylinder W / C flows into the reservoir 8 through the liquid path 13. At this time, the brake fluid that has flowed into the reservoir 8 by the operation of the piston pump P is pumped up through the fluid passage 11 and is returned to the master cylinder M / C. At the time of VDC operation, the gate-out valve 2 is closed, the pressure increasing valve 3 other than the pressure increasing valve 3 corresponding to the desired wheel is closed, and the pump unit P is operated. At this time, even if the check valve 7 is closed, the inside of the reservoir 8 is decompressed by pumping up the pump unit P, and the check valve 7 is pushed open. As a result, the brake fluid is pumped up from the master cylinder M / C, and the increased brake fluid is supplied to the necessary wheel cylinder W / C.

[Configuration of piston pump]
FIG. 2 is an axial sectional view of the piston pump P.
The piston pump P is configured by inserting a pump assembly 40 into a piston chamber 34 formed in the housing 33. The constituent members of the P-system piston pump PP and the S-system piston pump PS are the same and are provided symmetrically. Therefore, the following description will be mainly given with reference to the diagram of the P-system piston pump PP. In the following description, the axial direction of the piston pump P and the rightward direction in FIG. 2 is defined as the positive X-axis direction.
The pump assembly 40 includes a plug 41, a cylinder 42, a piston 43, a filter member 44, a seal ring 45, a guide member 46, a suction valve 49, and a discharge valve 53.
The cylinder 42 is formed in a bottomed cup shape, and a through-hole 42a penetrating outward is formed at the bottom. The side that opens to the outside of the through-hole 42a is formed so as to expand in a tapered shape, and constitutes a seat surface 42b on which the discharge valve 53 sits. A cylinder hole 42c for accommodating the piston 43 is formed on the inner periphery of the cylinder 42.

The piston 43 includes a small-diameter portion 43a extending in the X-axis positive direction, a large-diameter portion 43b formed on the X-axis negative side of the small-diameter portion 43a, and an axial suction liquid passage 43c formed in the piston 43 in the axial direction. And a radial suction liquid passage 43d formed in the piston 43 in the radial direction. The small diameter portion 43a is formed in a columnar shape, and is formed so as to satisfy the following expression, where d1 is the outer diameter of the small diameter portion 43a and d2 is the inner diameter of the cylinder hole 42c of the cylinder 42.
d2 ²・ π / 4: d1 ²・ π / 4 = 2: 1
The outer diameter of the large-diameter portion 43b is formed slightly smaller than the inner diameter of the cylinder hole 42c, and the piston 43 is provided so as to be slidable in the axial direction within the cylinder hole 42c. That is, the outer diameter of the large diameter portion 43b is larger than the outer diameter of the small diameter portion 43a, and the inner diameter of the cylinder hole 42c is larger than the outer diameter of the small diameter portion 43a.
A seal groove 43e is formed in the large diameter portion 43b, and a seal ring 48 is provided in the seal groove 43e. The cylinder hole 42c is liquid-tightly separated by the seal ring 48. Within the cylinder hole 42c, the X-axis negative direction side of the seal ring 48 constitutes the discharge chamber OUT, and the X-axis positive direction side constitutes the suction chamber IN. The axial suction liquid passage 43c is drilled from the end of the piston 43 on the X axis negative direction side in the positive direction until the tip reaches the small diameter portion 43a. An opening on the X-axis negative direction side of the axial suction liquid passage 43c is formed so as to increase in diameter in a tapered shape, and constitutes a seat surface 43f on which the suction valve 49 sits.

A spring locking member 51 is provided at the end of the piston 43 on the X axis negative direction side. The spring locking member 51 is formed in a bottomed cup shape, and a through hole 51a penetrating in the axial direction is formed at the bottom of the spring locking member 51. A flange portion 51b bent toward the outer periphery is formed in the opening portion on the X axis positive direction side of the spring locking member 51. A suction valve 49 is accommodated in the spring locking member 51, and the suction valve 49 is biased toward the seat surface 43f of the piston 43 between the bottom surface of the spring locking member 51 and the suction valve 49. A spring 50 is provided. A spring 52 that urges the piston 43 toward the cam 47 is provided between the X-axis negative side surface of the flange portion 51b and the bottom surface of the cylinder.
A filter member 44 is provided on the X axis positive direction side of the cylinder 42. The filter member 44 penetrates in the axial direction, the X-axis negative direction side end portion constitutes a cylinder engaging portion 44a, and the X-axis positive direction side end portion constitutes a piston through hole 44b. An end on the X axis positive direction side of the cylinder 42 is inserted on the inner peripheral side of the cylinder engaging portion 44a. The small diameter portion 43a of the piston 43 passes through the piston through hole 44b. A suction window 44d penetrating the inside and the outside of the filter member 44 is formed on the side surface of the filter member 44, and a fine mesh-like filter 44e is provided in the suction window 44d.
The plug 41 is formed with a valve body accommodating hole 41a that is concave on the X axis negative direction side with respect to the axial center portion on the side surface in the X axis positive direction. A spring 54 that urges the discharge valve 53 toward the seat surface 42b of the cylinder 42 is provided between the bottom surface of the valve body accommodating hole 41a and the discharge valve 53. On the outer peripheral side of the plug 41, a caulking portion 41b protruding in the positive direction of the X axis is formed. The caulking portion 41b is caulked so as to engage with a caulking groove 42d formed in a circumferential groove shape on the outer periphery of the cylinder 42 in the vicinity of the end portion on the X axis negative direction side.

The piston chamber 34 includes, in order from the X-axis positive direction side, a cam housing chamber 34a that houses a cam 47 that is eccentrically attached to the rotation shaft of the motor M, and a cylinder through-hole 34b through which the small-diameter portion 43a of the piston 43 passes. A seal ring housing portion 34c for housing the seal ring 45, a filter housing portion 34d formed with a larger diameter than the outer diameter of the filter member 44, and a cylinder holding portion 34e formed with a smaller diameter than the filter housing portion 34d. And a plug holding part 34f having a larger diameter than the cylinder holding part 34e.
A guide member 46 is accommodated on the X-axis positive direction side of the seal ring accommodating portion 34c with respect to the seal ring 45. The guide member 46 is formed in a ring shape, and the inner diameter is formed such that the small diameter portion 43a of the piston 43 can be stroked in the axial direction.
Although not visible in the cut surface of FIG. 2, a liquid passage 10b connected to the suction side of the piston pump P is opened in the filter housing portion 34d. The inner peripheral surface of the cylinder holding portion 34e is in contact with the outer peripheral surface of the cylinder 42. After the pump assembly 40 is inserted into the piston chamber 34, the plug holding portion 34f is attached to the housing 33 by crimping the negative side in the X-axis direction to contact the plug 41.

[Configuration of reservoir with check valve]
FIG. 3 is an axial sectional view showing configurations of the check valve 7 and the reservoir 8. FIG. 4 is an axial sectional view of the check valve 7. FIG. 5 is a perspective view of the filter member 70 of the check valve 7. Note that the P system check valve 7P and the reservoir 8P and the S system check valve 7S and the reservoir 8S have the same configuration, and therefore, the reference numerals are not described with reference numerals “P” and “S”.
A cylindrical bottomed hole 33b is formed below the housing 33 from the lower surface 33a upward. A retainer holding surface 33c is formed in the housing lower opening of the bottomed hole 33b, and the retainer holding surface 33c holds the retainer member 80 by caulking fixing 33d. The retainer member 80 is formed with a flange portion 80a whose outer peripheral edge is clamped by the caulking fixing 33d, a cylindrical portion 80b bent downward from the flange portion 80a, and a holding surface 80c for holding one end of the coil spring 82. An air hole 80d is formed substantially at the center of the closed portion. Thereby, the lower part of the piston body 83 is configured so that the atmospheric pressure always acts.

The bottomed hole 33b includes a piston contact surface 33e that contacts the piston surface 83a of the piston body 83, and a small-diameter cylindrical portion 33f that is smaller in diameter than the piston contact surface 33e and formed in the center of the bottomed hole 33b. Have. A liquid path 13 communicating with the pressure reducing valve 4 and a liquid path 10b communicating with the suction side of the pump unit P are connected to the small diameter cylindrical portion 33f. A cylindrical check valve housing hole 33g having a central axis OR at a position offset from the central axis of the bottomed hole 33b, that is, the central axis OP of the piston main body 83 to the left in the figure, is further above the small diameter cylindrical portion 33f. Is formed. A liquid passage 10a communicating with the master cylinder M / C is connected to the bottom of the check valve housing hole 33g.
In the check valve receiving hole 33g, a filter member 70 for removing impurities in the brake fluid flowing in from the liquid passage 10a and a seat member 71 constituting the check valve 7 while being fitted with the filter member 70 are accommodated. Yes. FIG. 4 is an enlarged cross-sectional view illustrating the configuration of the check valve 7 according to the first embodiment, and FIG. 5 is a perspective view of the filter member 70. The check valve 7 shown in FIG. 4 shows a state where the rod 72 is positioned at the lowermost end.

The filter member 70 is mainly formed of resin, and is a mesh-like cylindrical filter 70a, a stopper portion 70b that functions as a stopper of the ball valve 73, and a skeleton member of the filter member 70. A column part 70c attached to the inside, an annular shape formed below the column part 70c, a cylindrical part 70d connected to the column part 70c, and a crown surface facing the liquid channel 10a side of the filter member 70 A projection 70e is provided for securing a flow path between the liquid path 10a and the filter 70a. The protrusion 70e is in contact with the bottom of the check valve housing hole 33g as necessary to secure a flow path. The outer diameter of the filter member 70 is smaller than the check valve housing hole 33g, and a flow path between the outer periphery of the filter member 70 and the check valve housing hole 33g is secured.
In a region surrounded by the upper end of the seat member 71 and the filter member 70, a ball valve 73 and a check valve return spring 74 for urging the ball valve 73 toward the seat member 71 are attached. Note that the elastic force of the check valve return spring 74 is set to be weaker than the elastic force of the coil spring 82, and when the brake fluid pressure is not applied to the piston body 83, the ball valve 73 is caused by the elastic force of the coil spring 82. Is pushed up through the rod 72.

  The seat member 71 is a cylindrical member having a plurality of stepped portions, and has an upper cylindrical portion 71a that forms a fit with the filter member 70, a diameter larger than that of the upper cylindrical portion 71a, and is substantially the same as the check valve housing hole 33g. It has a middle cylindrical portion 71b having the same diameter, and a lower cylindrical portion 71c that is slightly larger in diameter than the middle cylindrical portion 71b. An engaging groove 71d is formed between the upper cylindrical portion 71a and the middle cylindrical portion 71b, and the check valve 7 is placed in the check valve housing hole 33g between the middle cylindrical portion 71b and the lower cylindrical portion 71c. An insertion groove 71e into which the housing material is inserted is formed during press-fitting. The filter member 70 and the seat member 71 are configured such that the upper cylindrical portion 71a of the seat member 71 in which the rod 72 is accommodated is inserted into the filter member 70 in a state where the check valve return spring 74 and the ball valve 73 are placed inside the filter member 70. It is inserted into the cylindrical part 70d. As a result, the engagement convex portion 70f of the filter member 70 and the engagement groove 71d of the seat member 71 are fitted together to form an integrated structure, and the check valve 7 is configured.

The seat member 71 includes a through hole 71f that forms a brake fluid passage between the rod 72 and the outer periphery of the rod 72 while accommodating a rod 72 that contacts the ball valve 73 at the axial center, and has a smaller diameter than the through hole 71f. A holding hole 71g that holds the hole in the radial direction, and a plurality of through holes 71h that are formed at positions surrounding the holding hole 71g from below the sheet member 71 and partially communicate with the lower end portion of the through hole 71f. A mortar-shaped seat surface 71i is formed on the ball valve 73 side of the through hole 71f. When the ball valve 73 is seated on the seat surface 71i, the brake fluid does not flow between the liquid passage 10a and the small diameter cylindrical portion 33f. On the other hand, when the ball valve 73 is pushed up against the force of the check valve return spring 74 by the rod 72, the brake fluid supplied from the liquid passage 10a passes through the filter 70a of the filter member 70 and the rod 71f and the rod. 72 flows through the gap between the outer periphery and the flow hole 71h to the small diameter cylindrical portion 33f.
The free length of the check valve return spring 74 is set to a length that allows the ball valve 73 to always be urged toward the seat member 71. As described above, the filter member 70 and the sheet member 71 are integrated with each other by fitting the engagement convex portion 70f and the engagement groove 71d, and the filter member 70 is used to absorb an assembly error. A small gap is set between the upper end of the protrusion (the upper end of the protrusion 70e) and the bottom of the check valve receiving hole 33g. At this time, even if the fitting between the filter member 70 and the seat member 71 is disengaged and the filter member 70 falls off, and the filter member 70 comes into contact with the bottom of the check valve housing hole 33g, the protrusion 70e Thus, a flow path between the liquid path 10a and the filter 70a is secured, and the ball valve 73 can be pressed against the seat surface 71i by the check valve return spring 74.

The rod 72 is a rod-shaped metal member having a larger diameter than the holding hole 71g and abutting the ball valve 73, and a rod tip 72a substantially the same diameter as the holding hole 71g and longer than the rod tip 72a. It has a formed rod intermediate portion 72b and a rod lower end portion 72c that has a tapered shape gradually reduced in diameter from the rod intermediate portion 72b and abuts against an upper surface 84a of a plate member 84 to be described later. The rod 72 is configured as a separate member from the piston main body 83. When the piston main body 83 strokes more than the length of the rod intermediate portion 72b, the rod lower end 72c is separated from the plate member upper surface 84a. In other words, the rod tip 72a functions as a stopper by contacting the upper end of the holding hole 71g. As described above, the center axis OR of the rod 72 is offset from the center axis OP (rotation center) of the piston main body 83.
The piston body 83 is a resin-molded member, and is formed in a bottomed cylindrical shape having a bottom portion 83b. On the outer periphery of the cylinder of the piston body 83, there is an upper outer peripheral portion 83c formed slightly smaller than the inner peripheral diameter of the bottomed hole 33b, and an annular formed below the upper outer peripheral portion 83c to accommodate the annular seal member 85 A groove 83d, a seal member holding portion 83e formed with substantially the same diameter as the inner peripheral diameter of the bottomed hole 33b, and holding the annular seal member 85, and an inner periphery of the bottomed hole 33b formed below the seal member holding portion 83e A diameter-reduced portion 83f having a diameter smaller than that of the upper outer peripheral portion 83c and a weld line forming portion 83g formed below the reduced-diameter portion 83f and having substantially the same diameter as the inner peripheral diameter of the bottomed hole 33b. And have. The annular seal member 85 is partitioned with the upper part as a hydraulic chamber and the lower part as an air chamber.

Here, the weld line is a position away from the gate position (injection port for injecting molten resin into the mold) when resin molding (insert molding), and the resin flowing into the mold is another It is a portion that remains as a joint trace between the resins when they are cooled and solidified while joining with the resin that has flowed in through the path. In general, a portion where a weld line is formed tends to be less accurate. In the first embodiment, the weld line forming portion 83g is provided below the annular seal member 85, that is, at a position partitioned as an air chamber. That is, the piston main body 83 is configured so that the weld line is formed at a position where accuracy related to liquid tightness or the like is not required, in other words, the weld line is not formed at a location where accuracy is required. .
The cylindrical portion inner periphery 83h of the piston body 83 is formed to have a slightly larger diameter than the coil spring 82, and the other end of the coil spring 82 is held at the bottom 83b. A plate member 84 made of stainless steel is assembled by insert molding as a hard body harder than the resin of the piston body 83 in the central region of the piston surface 83a formed on the upper surface of the piston body 83 (that is, the crown surface 83i). ing.

[12 valve brake fluid pressure control unit]
Normally, the piston pump P is provided on a hydraulic circuit having 12 valves. A reservoir with a check valve as described above is not used in a hydraulic circuit having 12 valves. The characteristics of the reservoir with the check valve will be described later. As a comparison, a hydraulic circuit having 12 valves and the gate-in valve 1 provided in the circuit will be described.
FIG. 6 shows a brake hydraulic pressure circuit of the 12-valve brake hydraulic pressure device 28. Only differences from the 10-valve brake fluid pressure device 32 (FIG. 1) will be described below.
The master cylinder M / C and the suction side of the pump P are connected by liquid passages 10P and 10S. On the liquid path 10, gate-in valves 1P and 1S which are normally closed on / off valves are provided. Check valves 24P and 24S are provided on the fluid passage 10 and between the gate-in valve 1 and the pump P. The check valve 24 is used for the flow of brake fluid from the master cylinder M / C to the pump P. Open and close against reverse flow

The wheel cylinder W / C and the reservoirs 26P and 26S are connected by liquid passages 13P and 13S. The reservoir 26 and the liquid path 10 are connected by liquid paths 27P and 27S. The liquid path 27 is connected between the gate-in valve 1 and the check valve 24 of the liquid path 10. On the liquid path 27, check valves 25P and 25S are provided. The check valve 25 is opened with respect to the flow of the brake fluid from the reservoir 26 toward the liquid path 10, and is closed with respect to the flow in the reverse direction. It is like that.
7 and 8 are axial sectional views of the gate-in valve 1, FIG. 7 shows a state when the gate-in valve 1 is closed, and FIG. 8 shows a state when the gate-in valve 1 is opened. Shows the state.

The gate-in valve 1 is mounted in a valve mounting hole 33 i formed in the middle of the liquid path 10 in the housing 33. The gate-in valve 1 includes a solenoid 100 that generates an electromagnetic force when energized, a fixed iron core 101 of a magnetic material, an armature 102 that is driven by the electromagnetic force, a hollow valve body 103 that serves as a cylinder of the armature 102, and a tip of the armature 102 The first member 104 whose first orifice 104a is opened and closed by the plunger 102a formed in the above, and the second member 105 whose second orifice 105a is opened and closed by the first member 104 are provided.
The appearance of the first member 104 is formed into a bottomed cup shape by press working, the bottom portion of the cup constitutes the first contact portion 104b, and the side portion constitutes the first outer peripheral wall 104c. The first outer peripheral wall 104c is formed with a communication hole 104d that communicates the inside and outside of the cup. The first contact portion 104b is formed with a first orifice 104a communicating with the inside and outside of the cup.

The appearance of the second member 105 is formed in a bottomed cup shape, and the outer peripheral side surface constitutes the second outer peripheral wall 105b. Further, the inner peripheral portion of the cup bottom of the second member 105 protrudes in the direction of the opening to constitute a second inner peripheral wall 105c. The protruding end portion of the second inner peripheral wall 105c constitutes a second contact portion 105g. A second orifice 105a that communicates the inside and outside of the second member 105 is formed in the second contact portion 105g. The second orifice 105a has a larger diameter than the first orifice 104a. The second outer peripheral wall 105b is formed with a suction window 105d that communicates the inside and outside of the second outer peripheral wall 105b. The suction window 105d is provided with a filter 105e. The second orifice 105a penetrates to the bottom of the second member 105, and the opening at the bottom constitutes a discharge port 105f.
A spring 106 is provided between the fixed iron core 101 and the armature 102, and the spring 106 biases the armature 102 in the valve closing direction. The first member 104 is provided so as to cover the second inner peripheral wall 105 c of the second member 105. A spring 107 is provided between the tip of the first outer peripheral wall 104c and the bottom of the second member 105, and urges the first member 104 in the valve opening direction.

When the gate-in valve 1 is closed, the plunger 102a at the tip of the armature 102 closes the first orifice 104a of the first member 104, and the first contact portion 104b of the first member 104 and the second of the second member 105 are second. The second orifice 105a is closed by contacting the contact portion 105g.
When the master cylinder pressure is generated when the gate-in valve 1 is closed, brake fluid is supplied from the suction window 105d of the second member 105, and a force acts on the armature 102 in the valve closing direction. . To open the gate-in valve 1 when the master cylinder pressure is generated, it is necessary to raise the armature 102 by generating an electromagnetic force that can counter the master cylinder pressure between the fixed core 101 and the armature 102. . Here, the electromagnetic force for pulling up the armature 102 can be reduced by forming the first orifice 104a of the first member 104 to have a small diameter.

When the armature 102 is pulled up and the first orifice 104a is opened, the brake fluid instantaneously flows from the first orifice 104a to the inner peripheral side of the second inner peripheral wall 105c of the second member 105, and the outer periphery of the second inner peripheral wall 105c. And the pressure difference between the inner circumference and the inner circumference becomes smaller. Therefore, the first member 104 moves in a direction in which the first contact portion 104b and the second contact portion 105g of the second member 105 are separated by the urging force of the spring 107, and the second orifice 105a is opened.
As a result, even when the master cylinder pressure is generated, the gate-in valve 1 can be opened with a small electromagnetic force, and the flow passage area when the valve is opened can be secured. In a normal piston pump, the suction stroke and the discharge stroke are alternately performed. Therefore, if the suction resistance is large, the discharge capacity may be reduced. Since the gate-in valve 1 can secure an opening area when the valve is opened, the suction resistance can be reduced even when the viscosity of the brake fluid is high at low temperatures.

[Characteristics of reservoir with check valve]
In the reservoir 8 with the check valve 7 of the first embodiment, the opening area when the check valve 7 is opened cannot be sufficiently taken. The reason why the opening area cannot be taken will be described below.
The first reason is that it is necessary to reduce the stroke amount of the ball valve 73 when the check valve 7 is opened.
When the master cylinder pressure is not generated, the ball valve 73 is pushed up by the piston body 83 via the rod 72, and the check valve is opened. When master cylinder pressure is generated by the driver operating the brake pedal B / P, the brake fluid is supplied to the piston body 83 side, the piston body 83 is pushed down, and the brake fluid pressure causes the ball valve 73 to be applied to the seat member 71. Since it acts in the pressing direction, the check valve 7 is closed.
In other words, the check valve 7 is opened immediately after the driver starts operating the brake pedal B / P, but the check valve 7 is closed when the master cylinder pressure is generated, and then the fluid is routed through the liquid passage 12. Thus, the brake fluid is supplied from the master cylinder M / C to the wheel cylinder W / C. Therefore, if the stroke of the ball valve 73 is large when the valve is opened, the brake fluid will flow into the reservoir 8 even if the brake pedal B / P is depressed, the wheel cylinder pressure will rise slowly, and the driver will It feels like you've stepped on and feels uncomfortable. Therefore, it is necessary to reduce the stroke of the ball valve 73 when the valve is opened.

The second reason is that it is necessary to reduce the diameter of the sheet surface 71i of the sheet member 71.
When the wheel cylinder pressure associated with the driver's brake pedal operation is insufficient, such as during a brake fade, it is necessary to operate the piston pump P to perform brake assist to increase the wheel cylinder pressure. When performing the brake assist, it is necessary to open the ball valve 73 pressed against the seat surface 71i by the master cylinder pressure by the biasing force of the coil spring 82 of the reservoir 8. At this time, if the diameter of the seat surface 71i is large, the force by which the ball valve 73 is pressed against the seat surface 71i exceeds the urging force of the coil spring 82 and the check valve 7 cannot be opened, and the piston pump P is Brake fluid cannot be inhaled from the M / C. Therefore, it is necessary to reduce the diameter of the seat surface 71i.

[Operation of piston pump]
In a normal piston pump, the suction stroke and the discharge stroke are alternately performed. Therefore, if the suction resistance is large, the discharge capacity may be reduced. Therefore, the gate-in valve as described above is used in the hydraulic circuit in which the piston pump is used, and the opening area when the gate-in valve is opened is ensured, even when the viscosity of the brake fluid is high. The inhalation resistance was made small.
When a gate-in valve is used, the number of parts is large and the cost increases. Since the gear pump performs the suction process and the discharge process at the same time, the brake pump is always sucked in the brake fluid. For this reason, even when the suction resistance of the gear pump is large, the brake fluid is always sucked little by little, so that a decrease in discharge capacity is suppressed. Therefore, the hydraulic circuit using a gear pump eliminates the gate-in valve and uses a reservoir with a check valve.
However, gear pumps are also more expensive than piston pumps. To reduce costs, it is conceivable to use a piston pump and abolish the gate-in valve and use a reservoir with a check valve.
Therefore, in the first embodiment, the piston pump P can be discharged and the suction of about half of the suction amount can be performed. FIG. 9 is a schematic diagram of the piston pump P, FIG. 9 (a) shows a state during discharge, and FIG. 9 (b) shows a state during inhalation.
As described above, the piston pump P of the first embodiment is formed so as to satisfy the following expression, where d1 is the outer diameter of the small diameter portion 43a and d2 is the inner diameter of the cylinder hole 42c of the cylinder 42.
d2 ²・ π / 4: d1 ²・ π / 4 = 2: 1
That is, the cross-sectional area of the suction chamber IN is half of the cross-sectional area of the discharge chamber OUT. At the time of discharge, the suction chamber IN expands, and brake fluid is sucked into the suction chamber IN from the outside of the cylinder 42 (portion indicated by A in FIG. 9A) (first suction stroke). When the cylinder 42 returns, the discharge chamber OUT expands, and brake fluid is sucked from the suction chamber IN into the discharge chamber OUT (part indicated by A in FIG. 9B), and at the same time, the brake is braked from outside the cylinder 42 to the discharge chamber OUT. Liquid is inhaled (portion indicated by B in FIG. 9B) (second inhalation step). When discharging, the brake fluid sucked into the discharge chamber OUT in the second suction stroke is discharged. Half of the amount of brake fluid at the time of discharge is sucked into the cylinder 42 from the outside in the first suction stroke, and the other half is sucked into the cylinder from the outside in the second suction stroke.
As a result, the piston pump P performs suction in two stages of the first suction process and the second suction process, so that the instantaneous suction flow rate can be suppressed and the suction resistance can be reduced even if the total suction amount is the same. Even when the brake fluid is highly viscous and the suction resistance is somewhat increased, it is possible to suppress a decrease in discharge capacity.

[effect]
The effects obtained in Example 1 are listed below.

(1) The fluid passage 12 (first fluid passage) connecting the master cylinder M / C and the wheel cylinder W / C and the brake fluid in the master cylinder M / C are sucked into the fluid passage 12 and discharged to the foil. Piston pump P (pump) for increasing cylinder pressure, liquid passage 10 (second liquid passage) connecting the master cylinder M / C and the suction side of the piston pump P, and a reservoir provided in the liquid passage 10 8 and a check valve 7 (check valve) that is provided in the fluid passage 10 and restricts the inflow of the brake fluid into the reservoir 8 by the master cylinder pressure generated by the driver's brake operation. A gate-out valve 2 (gate-out valve) provided between the M / C and the discharge side of the piston pump P. The piston pump P is provided with a piston chamber 34 formed in a housing 33 having respective liquid passages. Piston 4 provided to reciprocate inside (bore) 3 is a pump that performs a suction step and a discharge step of the brake fluid in accordance with the reciprocating motion of the piston 43. The piston pump P passes the brake fluid in the discharge chamber OUT through the discharge valve 53 in accordance with the forward movement. The first suction step of inflating the suction chamber IN and sucking the brake fluid from the liquid passage 10 into the suction chamber IN, and the brake fluid sucked into the suction chamber IN along with the backward movement A second suction step for sucking brake fluid from the fluid passage into the discharge chamber OUT.
Therefore, since the piston pump P performs the suction in two stages of the first suction process and the second suction process, the instantaneous suction flow rate can be suppressed and the suction resistance can be reduced even if the total suction amount is the same. Even when the brake fluid is highly viscous and the suction resistance is somewhat increased, it is possible to suppress a decrease in discharge capacity.

(2) The piston pump P includes a small-diameter portion 43a (piston small-diameter portion) facing the suction chamber IN and a cylinder hole 42c (discharge chamber) having a larger diameter than the small-diameter portion 43a.
Therefore, the brake fluid can be sucked into the suction chamber IN when the piston pump P discharges.
(3) When the inner diameter of the cylinder hole 42c is d2, and the diameter of the small diameter portion 43a is d1,
d2 ²・ π / 4: d1 ²・ π / 4 = 2: 1
It was.
Therefore, the suction amount of the piston pump P can be smoothed, a decrease in the suction amount due to the suction resistance can be suppressed, and a decrease in the discharge capacity can be suppressed.

[Other Examples]
As described above, the present invention has been described based on the first embodiment. However, the specific configuration of each invention is not limited to each embodiment, and even if there is a design change or the like without departing from the gist of the invention. Are included in the present invention.

2 Gate-out valve
7 Check valve
8 Reservoir
10 fluid paths
12 liquid channel
33 Housing
34 Piston chamber (bore)
42c Cylinder hole (discharge chamber)
43a Small diameter part (piston small diameter part)
M / C master cylinder
W / C wheel cylinder
PP, PS piston pump

Claims (3)

A first fluid path connecting the master cylinder and the wheel cylinder;
A pump for sucking in brake fluid in the master cylinder and discharging it to the first fluid path to increase the wheel cylinder pressure;
A second fluid path connecting the master cylinder and the suction side of the pump;
A reservoir provided in the second liquid path;
A check valve that is provided in the second fluid path and restricts inflow of the brake fluid into the reservoir by a master cylinder pressure by a brake operation of the driver;
A gate-out valve provided on the first liquid path and between the master cylinder and a discharge side of the pump;
With
The pump is a piston pump that includes a piston that can reciprocate in a bore formed in a housing having each liquid passage, and that performs a brake fluid suction process and a discharge process in accordance with the reciprocation of the piston. And
The piston pump discharges the brake fluid compressed in the discharge chamber in accordance with the forward movement to the wheel cylinder side through the discharge valve, and expands the suction chamber to enter the suction chamber from the second liquid path. A first suction step for sucking the brake fluid, and a second suction step for sucking the brake fluid sucked into the suction chamber and the brake fluid from the second fluid passage into the discharge chamber in the backward movement. Brake device characterized by that. The brake device according to claim 1, wherein
The piston device includes a piston small-diameter portion facing the suction chamber and a discharge chamber having a larger diameter than the piston small-diameter portion. The brake device according to claim 2,
When the inner diameter of the discharge chamber is d2, and the diameter of the piston small diameter portion is d1,
d2 ²・ π / 4: d1 ²・ π / 4 = 2: 1
Brake device characterized by that.

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