JP2011073518A - Brake fluid pressure control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lengthen control time during pressure reduction control and to improve the sureness of a fail-safe function. <P>SOLUTION: A brake fluid pressure control device for a vehicle includes: release passages Q1, Q2 which interconnect an open-to-air tank provided in a master cylinder MC1 and a normally-closed solenoid valve to return hydraulic fluid escaped through the normally-closed solenoid valve to the tank; and a release passage valve 30 provided for the release passages Q1, Q2 and operated by means of the differential pressure between a brake fluid pressure of the master cylinder MC1 and a brake fluid pressure of a wheel cylinder to close or open the release passages Q1, Q2. The release passage valve 30 is a normally closed valve including: a valve element 31 disposed inside a cylinder to open or close the release passages Q1, Q2; and a piston 32 to move to push the valve element 31 using the differential pressure between the brake fluid pressure of the master cylinder MC1 and the brake fluid pressure of the wheel cylinder. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a vehicle brake hydraulic pressure control device.

Conventionally, what was indicated by patent documents 1 as a brake fluid pressure control device for vehicles is known.
In this vehicle brake hydraulic pressure control apparatus, an inlet valve that allows transmission of brake hydraulic pressure from a master cylinder side to a wheel cylinder of a wheel brake (hereinafter sometimes simply referred to as a wheel brake), a wheel brake, An outlet valve that releases the internal hydraulic pressure, a reservoir that absorbs the brake hydraulic pressure released by opening the outlet valve, and the like are mainly provided, and the hydraulic circuit does not have a pump. In this vehicular brake hydraulic pressure control device, when the brake lever is operated and the brake hydraulic pressure acts on the wheel brake, the anti-lock brake control is performed when the wheel is about to lock.

  In the antilock brake control, when the pressure reduction control for reducing the brake fluid pressure is executed, the inlet valve is closed and the outlet valve is opened. If it does in this way, since the brake fluid which exists in the wheel brake side rather than an inlet valve will flow into a reservoir, the brake fluid pressure which acted on the wheel brake will reduce pressure.

  By the way, in the vehicle brake hydraulic pressure control device, the capacity of the reservoir is set to a small amount so as to realize a fail-safe function of ensuring the minimum necessary braking force. For this reason, it is difficult to take a long control time during the pressure reduction control.

In this regard, there is disclosed a vehicle brake fluid pressure control device in which brake fluid released by opening an outlet valve is absorbed by a reservoir tank of a master cylinder (see Patent Document 2).
In this vehicle brake fluid pressure control device, the brake fluid released from the outlet valve can flow into the reservoir tank of the master cylinder at the time of pressure reduction control of the antilock brake control, and the control time at the time of pressure reduction control is lengthened. It is possible.

JP-A-9-207739 JP-T-2007-520391

  However, in the vehicle brake fluid pressure control device disclosed in Patent Document 2, if a situation occurs in which brake fluid flows out of the outlet valve during normal braking, the brake fluid that flows out of the outlet valve is stored in the reservoir of the master cylinder. Since there is a possibility of flowing into the tank, it is necessary to further improve the fail-safe function of ensuring the minimum required braking force.

  An object of the present invention is to provide a vehicular brake hydraulic pressure control device that can take a long control time during pressure reduction control and can improve the certainty of a fail-safe function.

  The present invention devised to solve such problems has a normally open solenoid valve and a normally closed solenoid valve disposed between a master cylinder and a wheel cylinder of a wheel brake, and an antilock brake control. In the vehicular brake hydraulic pressure control device capable of executing the above, the open air tank provided in the master cylinder and the normally closed solenoid valve are connected and escaped through the normally closed solenoid valve. An open path for returning the hydraulic fluid to the tank, and provided in the open path, operates using a differential pressure between the brake hydraulic pressure of the master cylinder and the brake hydraulic pressure of the wheel cylinder, and shuts off the open path or And an open path valve that opens.

According to such a brake fluid pressure control device for a vehicle, since the release path is provided with an open path valve that operates using a differential pressure between the brake fluid pressure of the master cylinder and the brake fluid pressure of the wheel cylinder, For example, when the pressure difference between the brake fluid pressure in the master cylinder and the brake fluid pressure in the wheel cylinder occurs, the open passage valve can be opened by opening the open passage valve, and the differential pressure disappears. The open path valve can be closed by closing the open path valve.
As a result, for example, at the time of pressure reduction control of the antilock brake control, the open-circuit valve is opened by the differential pressure generated between the brake fluid pressure of the master cylinder and the brake fluid pressure of the reduced wheel cylinder. The hydraulic fluid released through the closed solenoid valve can be returned to the master cylinder through the open path. Therefore, the control time during the pressure reduction control can be made longer than in the case where the brake fluid pressure is reduced only by flowing the brake fluid into the reservoir as in the prior art. Thereby, the degree of freedom of control can be increased.

Further, during normal braking, the brake fluid pressure of the master cylinder and the brake fluid pressure of the wheel cylinder become the same pressure and there is no differential pressure. Therefore, the open passage valve can be closed to close the open passage. .
Therefore, in the event of normal braking, even if a situation occurs in which hydraulic fluid flows out of the normally closed solenoid valve into the open path, the open path valve is blocked by the closed open path valve. The working fluid can be prevented from returning to the master cylinder.
Thereby, the certainty of the fail-safe function can be increased.

  Further, according to the present invention, the open path valve is a normally closed valve, and includes a cylinder, a valve body and a piston arranged in series in the cylinder, and the valve body includes the open path. Is moved to a first position where the open path is opened, and is biased toward the first position by a first biasing means, and the piston is When a differential pressure is generated between the brake fluid pressure of the master cylinder and the brake fluid pressure of the wheel cylinder, the first urging means slides toward the valve body with a thrust using the differential pressure. It is preferable to push the valve body from the first position to the second position against the urging force.

According to such a brake fluid pressure control device for a vehicle, when a pressure difference is generated between the brake fluid pressure of the master cylinder and the brake fluid pressure of the wheel cylinder during the decompression control of the antilock brake control, Slides toward the valve body with a thrust using differential pressure, and pushes the valve body from the first position to the second position against the urging force of the first urging means. As a result, the open path is opened.
Therefore, during the decompression control of the antilock brake control, the hydraulic fluid released through the normally closed solenoid valve is returned to the master cylinder through the open path, and only the brake fluid is allowed to flow into the reservoir as in the past. As a result, the control time during the pressure reduction control can be made longer than when the brake fluid pressure is reduced. Therefore, the degree of freedom of control can be increased.

  Also, when the decompression control of the anti-lock brake control ends, or during normal braking, the differential pressure between the brake fluid pressure of the master cylinder and the brake fluid pressure of the wheel cylinder disappears, and the thrust using the differential pressure disappears, Pushing by the piston is released. As a result, the valve body is returned from the second position to the first position by the urging force of the first urging means, and the open path is closed. Therefore, the working fluid is prevented from returning to the master cylinder.

  In addition, the open path valve is automatically opened by the differential pressure generated during the pressure reduction control of the antilock brake control in this way, and then the open path valve is automatically closed when the differential pressure disappears. Therefore, compared to, for example, open / close control of an open path using a solenoid valve, complicated control is not required, and the open path is opened or closed with simple control using differential pressure. Can be done easily.

  Further, since no electric power is consumed to open and close the open-circuit valve, a vehicle brake hydraulic pressure control device that can reduce power consumption can be obtained.

  Further, according to the present invention, the piston has a wheel brake fluid pressure chamber on which the brake fluid pressure of the wheel cylinder acts on one end surface via a seal member, and a master on the other end surface opposite to the one end surface. And a master cylinder hydraulic pressure chamber on which the cylinder brake hydraulic pressure acts, and is urged toward the other end face by a second urging means, and is generated by the brake hydraulic pressure of the master cylinder. When the thrust of 1 is larger than the second thrust generated by the brake hydraulic pressure of the wheel cylinder and the resultant force of the urging force by the second urging means, the valve body slides toward the one end face side. It is good to make it the structure which pushes.

  According to such a brake fluid pressure control device for a vehicle, the piston has a first thrust generated by the brake fluid pressure of the master cylinder, a second thrust generated by the brake fluid pressure of the wheel cylinder, and a biasing force by the second urging means. Since it slides and pushes the valve body when the resultant force is larger than the resultant force, thrust can be generated in the piston with a simple configuration utilizing differential pressure.

  Further, the present invention is configured such that the piston directly contacts the valve body and pushes the valve body, and the piston is in an initial position before sliding toward the valve body. In addition, it is preferable that a gap as a dimension adjustment margin is formed between the valve body and the piston.

  According to such a brake fluid pressure control device for a vehicle, when the piston is in an initial position before sliding toward the valve body, a gap serving as a dimension adjustment margin is formed between the valve body and the piston. Therefore, it is possible to secure a sufficient distance between the valve body and the piston in consideration of dimensional tolerance and assembly tolerance. As a result, the piston does not come into contact with the valve body at the initial position, and the valve body is reliably held at the first position by the first urging means. Therefore, the closed state of the open path can be maintained well.

  According to the vehicle brake hydraulic pressure control device of the present invention, it is possible to increase the control time during pressure reduction control and to improve the reliability of the fail-safe function.

It is a brake fluid pressure circuit diagram of the brake fluid pressure control device for vehicles of this embodiment. It is an expanded sectional view which shows the structure of a master cylinder. It is a schematic structure figure showing the valve for open ways of the brake fluid pressure control device for vehicles of a 1st embodiment. (A)-(c) is a schematic explanatory drawing which shows operation | movement of the valve for open paths.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.
(First embodiment)
In the drawings to be referred to, FIG. 1 is a brake fluid pressure circuit diagram of a vehicle brake fluid pressure control device according to an embodiment of the present invention.

  As shown in FIG. 1, a vehicle brake hydraulic pressure control device (hereinafter referred to as “brake control device”) U according to this embodiment includes a motorcycle, an automatic tricycle, an all-terrain vehicle (ATV), an automatic four-wheel vehicle, and the like. The braking force (brake hydraulic pressure) applied to the vehicle wheels is appropriately controlled. Below, although the example which applied the brake control apparatus U to the motorcycle is demonstrated, it is not the meaning which limits the vehicle by which the brake control apparatus U is mounted.

  The brake control device U is configured to include a front-wheel brake system K1 and a rear-wheel brake system K2. The brake system K1 on the front wheel side brakes the wheel brake F of the front wheel in accordance with the operation of the brake lever L1, and appropriately controls the braking force applied to the wheel brake F by the control device 6 as a control means. The anti-lock brake control of the wheel brake F is possible. The brake system K2 on the rear wheel side is configured as a conventional brake in which the wheel brake R is directly operated by operating the brake lever L2.

Hereinafter, the brake hydraulic circuit shown in FIG. 1 will be described in detail.
The brake system K1 includes a flow path from the inlet port J1 leading to the master cylinder MC1 to the outlet port J2. In addition, an open port J3 that communicates with the return port 11b of the master cylinder MC1 is provided. The master cylinder MC1 and the inlet port J1 are connected by a pipe H1, and the outlet port J2 is connected to a front wheel brake F (wheel cylinder of the wheel brake F) through the pipe H2. The open port J3 and the return port 11b are connected by a pipe H3.

The master cylinder MC1 has a cylinder 10 to which an oil reserve tank 10A for storing brake fluid as hydraulic fluid is connected. The master cylinder MC1 slides in the axial direction of the cylinder 10 by operating the brake lever L1. The piston 11 that flows out the brake fluid is assembled.
As shown in FIG. 2, a pair of cup seals 12 and 13 are arranged on the outer periphery of the piston 11 at intervals in the axial direction. These cup seals 12 and 13 are connected to the inner periphery of the cylinder 10. Closely slidably contact the surface.
A hydraulic chamber 14 is formed between the cup seal 12 and the end wall of the cylinder 10, and a return spring 15 that biases the piston 11 in the backward direction (rightward in the drawing) is contracted in the hydraulic chamber 14. Yes. The hydraulic chamber 14 is formed with an inlet / outlet port 15a for brake fluid. A pipe H1 is connected to the entrance / exit 15a.

An annular refilling oil chamber 11 a is formed on the outer periphery of the piston 11 between the cup seals 12 and 13. A brake fluid return port 11b is formed so as to communicate with the replenishing oil chamber 11a. A pipe H3 is connected to the return port 11b.
Between the cylinder 10 and the oil reserve tank 10A, when the piston 11 is located at the last retracted position, a relief port 16 that communicates between the hydraulic chamber 14 and the oil reserve tank 10A immediately before the cup seal 12 and the piston 11 Regardless of the forward / backward movement, a supply port 17 that always communicates between the replenishing oil chamber 11a and the oil reserve tank 10A is provided.

  As a result, when the piston 11 is in the last retracted position, the pressure in the hydraulic chamber 14 is released into the oil reserve tank 10A via the relief port 16, but the piston 11 is driven forward by operation of the brake lever L1. When the cup seal 12 crosses the relief port 16, hydraulic pressure can be generated in the hydraulic chamber 14. Further, when the hydraulic chamber 14 is depressurized below the pressure of the replenishing oil chamber 11 a when the piston 11 is retracted, the outer peripheral lip portion of the cup seal 12 contracts due to the pressure difference between both chambers, and the replenishing oil passes through the left end outer peripheral portion of the piston 11. Brake fluid flows into the hydraulic chamber 14 from the chamber 11a. As a result, the brake fluid is replenished.

  The cylinder 10 is assembled with a stop plate 18, a dust boot 19 and the like. In addition, a protector 20 is installed at the bottom of the oil reserve tank 10A to prevent the bubbles from entering the cylinder when bubbles are generated by undulations inside the oil reserve tank 10A. A reservoir cap 23 is fixed to the opening via a diaphragm 22 by a screw 21 screwed into the screw hole 21a.

Next, the brake system K1 will be described with reference to FIG.
The brake system K1 includes a front wheel control valve unit 1, a check valve 5, a reservoir 4 (reducing pressure reservoir), an open-path valve (normally closed valve) 30, and a control device 6. . The front wheel control valve unit 1 includes an inlet valve 2, an outlet valve 3, and a check valve 2a.

Here, the flow path (oil path) from the inlet port J1 to the inlet valve 2 is referred to as “output hydraulic pressure path D1”, and the flow path from the inlet valve 2 to the outlet port J2 is referred to as “wheel hydraulic pressure path E1”. The flow path from the wheel hydraulic pressure path E1 to the reservoir 4 through the outlet valve 3 and from the reservoir 4 to the open path valve 30 is referred to as “open path Q1” and reaches the open port J3 through the open path valve 30. The flow path is referred to as “open path Q2”, and the flow path from the open path Q1 to the output hydraulic pressure path D1 through the check valve 5 is referred to as “return path T1”.
The flow path from the output hydraulic pressure path D1 to the open path valve 30 is referred to as “output hydraulic pressure branch path D2,” and the flow path from the wheel hydraulic pressure path E1 to the open path valve 30 is referred to as “wheel hydraulic pressure branch. This is referred to as “Road E2”.

  The front wheel control valve unit 1 opens the wheel hydraulic pressure path E1 (inlet valve 2 is open) and shuts off the open path Q1 (outlet valve 3 is closed) (in normal braking or in antilock brake control) During control), the wheel hydraulic pressure path E1 is shut off (inlet valve 2 is closed), and the open path Q1 is opened (outlet valve 3 is opened) (at the time of pressure reduction control in antilock brake control), and the wheel hydraulic pressure path It has the function of switching the state (during holding control in antilock brake control) that shuts off E1 and the open path Q1 (the inlet valve 2 and the outlet valve 3 are closed).

The inlet valve 2 is a normally-open electromagnetic valve interposed between the output hydraulic pressure path D1 and the wheel hydraulic pressure path E1. The inlet valve 2 is normally open, thereby allowing the brake hydraulic pressure from the master cylinder MC1 to be transmitted from the output hydraulic pressure path D1 to the wheel brake F through the wheel hydraulic pressure path E1.
Further, the inlet valve 2 is closed under the control of the control device 6 when the front wheel is about to be locked, so that the brake hydraulic pressure from the master cylinder MC1 is transferred from the output hydraulic pressure path D1 to the wheel hydraulic pressure path E1. The transmission to the brake F is cut off.

  The outlet valve 3 is a normally closed electromagnetic valve interposed between the wheel hydraulic pressure path E1 and the open path Q1. The outlet valve 3 is normally closed, but is released by the control of the control device 6 when the front wheel is about to be locked, so that the brake hydraulic pressure acting on the wheel brake F can be released from the wheel hydraulic pressure path E1. Escape to open path Q1 (during pressure reduction control in antilock brake control). As a result, the brake fluid released to the open path Q1 temporarily flows into the reservoir 4 and flows through the open path Q2 through the open path valve 30 opened as described later, and returns to the master cylinder MC1. It is.

  The check valve 2a is connected to the inlet valve 2 in parallel. This check valve 2a is a valve that only allows the brake fluid to flow from the wheel brake F side to the master cylinder MC1, and when the input from the brake lever L1 is released, the inlet valve 2 is closed. Even in this case, the brake fluid is allowed to flow from the wheel brake F side to the master cylinder MC1 side.

  The reservoir 4 is provided in the release path Q1, and has a function of temporarily storing brake fluid released from the wheel hydraulic pressure path E1 when the outlet valve 3 is opened. The brake fluid temporarily stored in the reservoir 4 is pushed out to the open path Q1 by the elastic force of the spring 4a provided therein, and is returned to the master cylinder MC1 through the open path valve 30 and the open path Q2.

  The check valve 5 is a one-way valve provided on the return path T1. The check valve 5 only allows the brake fluid to flow from the open path Q1 side to the master cylinder MC1 side, and when the input from the brake lever L1 is released, the brake fluid from the reservoir 4 side to the master cylinder MC1 side. Allow inflow.

  The open path valve 30 is a normally closed valve provided between the open paths Q1 and Q2. The open-circuit valve 30 is normally closed, but when the front wheel is about to be locked (during anti-lock brake control), the brake fluid pressure of the master cylinder MC1 and the brake fluid of the wheel cylinder of the wheel brake F are set. The valve is configured to open using a differential pressure between the pressure (hereinafter simply referred to as the brake fluid pressure of the wheel brake F). When the open path valve 30 is opened, the brake fluid released to the open path Q1 through the outlet valve 3 is returned from the open path valve 30 to the master cylinder MC1 through the open path Q2. A detailed description of the open path valve 30 will be given later.

On the other hand, the second brake system K2 is for braking the rear wheel as described above, and is connected to the wheel brake R of the rear wheel from the master cylinder MC2 which is a hydraulic pressure source through the pipe H4.
Thus, when the brake lever L2 is operated, the brake fluid from the master cylinder MC2 acts directly on the wheel brake R.
Note that the second brake system K2 may be configured such that a wire is used instead of the pipe H4 so that the operating force of the brake lever L2 is directly transmitted to the wheel brake R via the wire.

  Measurement values from a wheel speed sensor or the like attached to a wheel (not shown) are input to the control device 6, and the control device 6 operates the inlet valve 2 and the outlet valve 3 of the brake system K1 based on the measurement values. Control.

As shown in FIG. 3, the open path valve 30 includes a cylinder 30a, a valve body 31 and a piston 32 disposed in the cylinder 30a.
The cylinder 30a has a cylindrical shape and includes stepped cylindrical storage chambers S1 and S2 communicating with each other in the axial direction. A valve body 31 is disposed in the storage chamber S1, and a piston 32 is disposed in the storage chamber S2.
The storage chamber S1 includes a first hole wall 311 and a second hole wall 312 having a smaller diameter than the first hole wall 311. A bottomed cylindrical lid member 316 is attached to the opening of the first hole wall portion 311 via a seal member (not shown), and is connected to the lid member 316 on the inner side of the first hole wall portion 311. An inflow chamber V1 into which brake fluid flows is formed through the open path Q1. The inflow chamber V1 is separated from the outflow chamber V2 adjacent to the other end side by the seal member 34a.
The lid member 316 is fixed by a ring-shaped retaining member (not shown) attached from the opening side.

The valve body 31 disposed in the storage chamber S1 has a stepped columnar shape, and slides in the axial direction in the storage chamber S1 to communicate or block between the open path Q1 and the open path Q2. Is playing a role.
Specifically, the valve body 31 is slidably disposed in the first hole wall portion 311 and slidably disposed in the second hole wall portion 312, and is slidably disposed in the first hole wall portion 311 from the large diameter portion 31A. A small-diameter portion 31B having a small diameter, and a body portion 31C that connects the large-diameter portion 31A and the small-diameter portion 31B.

  The large-diameter portion 31A is a portion having a function as a valve. One end surface 31a of the large-diameter portion 31A faces the inner surface 316a of the lid member 316, and the other end surface 31a ′ is formed between the first hole wall portion 311 and the second hole wall portion 312. It faces the step surface 313 formed therebetween. Between the one end surface 31a of the large diameter portion 31A and the inner surface 316a of the lid member 316, a spring member 315 as a first urging means is contracted. Accordingly, the valve body 31 is urged toward the other end in the accommodation space S1, and the first position where the other end surface 31a ′ of the large diameter portion 31A abuts against the step surface 313 with an urging force. It is configured to take.

  In the present embodiment, an annular concave groove is formed in the other end surface 31a ′ of the large-diameter portion 31A, and an annular elastic member 34a (for example, an O-ring) that functions as a seal member is mounted in the concave groove. . Therefore, when the valve body 31 is urged to the other end side by the urging force of the spring member 315, the elastic member 34a mounted on the other end surface 31a ′ is elastically seated on the step surface 313 in a liquid-tight manner. ing.

On the other hand, an outflow chamber V <b> 2 is formed inside the second hole wall 312.
The outflow chamber V2 is formed by being surrounded by the inner surface of the second hole wall portion 312, the other end surface 31a 'of the large diameter portion 31A, the one end surface 31b' of the small diameter portion 31B, and the outer peripheral surface of the trunk portion 31C. It has a substantially cylindrical shape.
An end portion of the open channel Q2 is opened on the inner surface of the second hole wall 312 constituting the outflow chamber V2, and the outflow chamber V2 and the open channel Q2 are configured to communicate with each other. ing.
The outflow chamber V2 is partitioned from the inflow chamber V1 at one end side by a seal member 34a and from the atmospheric chamber V5 at the other end side by a seal member 34b.

  The sliding toward the other end side of the valve body 31 is restricted by the other end surface 31b of the small diameter portion 31B coming into contact with the step surface 314 formed on the other end side of the second hole wall portion 312. . Thus, the elastic member 34a of the large-diameter portion 31A is configured to be in close contact with the stepped surface 313 in a state in which sealing performance is ensured in a state where sliding toward the other end side of the valve body 31 is restricted. Has been. That is, the elastic member 34a does not contact the stepped surface 313 more strongly than necessary, and the elastic member 34a is not deformed. Therefore, it is excellent in durability and a good sealing property can be secured over a long period of time.

  Further, the valve body 31 is slid toward one end side by being directly pushed by the piston 32, and the second end surface 31 a ′ of the large diameter portion 31 </ b> A is separated from the step surface 313. The position can be taken. That is, the valve body 31 is pushed by the piston 32 when the piston 32 slides to one end side with a thrust (first thrust) against the urging force of the spring member 315 acting on the valve body 31. To the second position (see FIG. 4C). When the valve body 31 moves to the second position, the inflow chamber V1 and the outflow chamber V2 communicate with each other through the gap between the other end surface 31a 'of the large diameter portion 31A and the step surface 313.

The storage chamber S2 includes a third hole wall 323, a fourth hole wall 324 having a smaller diameter than the third hole wall 323, and a fifth diameter having a smaller diameter than the fourth hole wall 324. And a hole wall portion 325. A bottomed cylindrical lid member 326 is attached to the opening of the third hole wall portion 323 via a seal member (not shown). In the bottomed cylindrical holding portion 326b formed in the lid member 326, an end portion of the communication pipe A1 communicating with the atmosphere side is opened.
The lid member 326 is fixed by a ring-shaped retaining member (not shown) attached from the opening side.

  The piston 32 disposed in the storage chamber S2 has a stepped columnar shape, and uses a differential pressure between the brake fluid pressure of the master cylinder MC1 and the brake fluid pressure of the wheel brake F in the storage chamber S2. The valve body 31 is pushed so as to slide toward the side 31 and open between the open path Q1 and the open path Q2 (so that the inflow chamber V1 and the outflow chamber V2 communicate with each other). It has become. That is, the piston 32 functions as a drive device for opening the valve body 31.

  Specifically, the piston 32 is provided integrally with a base portion 32A slidably disposed in the third hole wall portion 323, and one end side of the base portion 32A, and is slidable on the fifth hole wall portion 325. One end side insertion portion 32B inserted through the base portion 32A and the other end side insertion portion 32C provided integrally with the other end side of the base portion 32A and slidably inserted into the holding portion 326b of the lid member 326. .

The base portion 32A is attached to the third hole wall portion 323 via a seal member 32c (O-ring), and the brake fluid pressure of the wheel brake F is introduced to the one end surface 32a side with the seal member 32c as a boundary. A wheel brake fluid pressure chamber V3 is formed, and a master cylinder fluid pressure chamber V4 into which the brake fluid pressure of the master cylinder MC1 (see FIG. 1) is introduced is formed on the other end surface 32b side.
Here, one end side of the wheel brake hydraulic pressure chamber V3 is partitioned from the atmospheric chamber V5 by a seal member 32e (O-ring), and the other end side is partitioned by a seal member 32c. The master cylinder fluid pressure chamber V4 is partitioned from the wheel brake fluid pressure chamber V3 at one end side by a seal member 32c and from the communication pipe A1 side by a seal member 32d at the other end side.
Note that the distance between the stepped portion 327 and one end surface 32a of the base portion 32A in the wheel brake hydraulic chamber V3 is L1, and the distance between the one end surface 326c of the lid member 326 and one end portion of the concave groove 32f that accommodates the seal member 32d is L2. Is set to satisfy the relationship of L1 <L2. This prevents the seal member 32d from falling off.
Further, when the distance between the other end of the communication pipe A2 in the atmospheric chamber V5 and one end of the recessed groove 32g that accommodates the sealing member 32e is L3, the relationship is set so that L1 <L3. Yes. This prevents the sealing member 32e from closing the communication pipe A2.

The wheel brake hydraulic pressure chamber V3 includes an inner surface of the third hole wall portion 323, an inner surface of the fourth hole wall portion 324, step portions 327 and 328, one end surface 32a of the base portion 32A, and an outer periphery of the one end side insertion portion 32B. It is formed by being surrounded by a surface, and has a substantially stepped cylindrical shape.
An end portion of the wheel hydraulic pressure branch E2 is opened on the inner surface of the fourth hole wall portion 324 constituting the wheel brake hydraulic pressure chamber V3, whereby the brake hydraulic pressure acting on the wheel hydraulic pressure channel E1 is reduced. It acts on the wheel brake fluid pressure chamber V3 via the wheel fluid pressure branch E2.
During normal braking, the brake fluid pressure acting on the wheel fluid pressure passage E1 is the same as the brake fluid pressure from the master cylinder MC1. Further, at the time of the pressure reduction control in the antilock brake control, the brake fluid pressure (the brake fluid pressure lower than the brake fluid pressure from the master cylinder MC1) of the wheel brake F acts on the wheel brake fluid pressure chamber V3.

In the wheel brake hydraulic chamber V3, a spring member 329 that functions as a second urging means is contracted between the one end surface 32a of the base portion 32A and the step portion 328. Accordingly, the piston 32 is urged toward the other end side in the storage chamber S2, and the other end side insertion portion 32C is formed at the bottom of the bottomed cylindrical holding portion 326b formed in the lid member 326. It is comprised so that it may contact | abut with urging | biasing force.
Here, the spring force of the spring member 329 is set larger (stronger) than that of the spring member 315 as the first urging means.

  In the present embodiment, the state where the other end side insertion portion 32 </ b> C is in contact with the bottom of the holding portion 326 b of the lid member 326 is the initial position of the piston 32. And in the state where piston 32 is located in this initial position, it is between the front-end | tip part of the protrusion part 330 formed in the one end part of the one end side insertion part 32B, and the other end surface 31b of the small diameter part 31B in the valve body 31. A gap P is formed as a dimension adjustment allowance. That is, when the piston 32 is in the initial position, the piston 32 does not contact the valve body 31.

In the present embodiment, an atmospheric chamber V <b> 5 is formed between the valve body 31 and the piston 32. The atmosphere chamber V5 is formed by being surrounded by the other end surface 31b of the small diameter portion 31B of the valve body 31, the tip end portion of the protruding portion 330 of the piston 32, and the fifth hole wall portion 325, and communicates with the atmosphere side. The end portion of the communication pipe A2 that opens is open to the inner surface of the fifth hole wall portion 325.
Note that the atmospheric chamber V5 is partitioned from the outflow chamber V2 at one end side by a seal member 34b and separated from the wheel brake fluid pressure chamber V3 by the seal member 32e at the other end side.

The master cylinder hydraulic pressure chamber V4 is surrounded by the inner surface of the third hole wall portion 323, the other end surface 32b of the base portion 32A, the outer peripheral surface of the other end side insertion portion 32C, and the one end surface 326c of the lid member 326. It is formed and has a cylindrical shape.
An end portion of the output hydraulic pressure branch D2 is opened on the inner surface of the third hole wall portion 323 constituting the master cylinder hydraulic pressure chamber V4, thereby acting on the output hydraulic pressure channel D1 (see FIG. 1). The brake hydraulic pressure of the master cylinder MC1 acting on the master cylinder hydraulic pressure chamber V4 is applied via the output hydraulic pressure branch passage D2.

Here, the piston 32 has a thrust generated by the brake fluid pressure of the master cylinder MC1 (first thrust), a thrust generated by the brake fluid pressure of the wheel brake F (second thrust), and an urging force by the spring member 329. When the valve opening pressure takes account of the sliding resistance and the like, the magnitude of the urging force of the spring member 329 and the base portion so as to slide and push the valve element 31 when the valve opening pressure takes into account the sliding resistance and the like. The size of the pressure receiving area of the one end surface 32a of 32A and the size of the pressure receiving area of the other end surface 32b are respectively adjusted.
By such adjustment, the piston 32 is moved to the initial position by the biasing force of the spring member 329 when the brake fluid pressure acting on the wheel brake fluid pressure chamber V3 and the master cylinder fluid pressure chamber V4 is the same pressure. It is set to be located. Further, the pressure is set so as to slide to one end side when a differential pressure is generated between the two brake fluid pressures and becomes the valve opening pressure.

Next, normal brake and antilock brake control on the front wheel side realized by such a brake control device U will be described with reference to the drawings.
(Normal brake)
When the piston 11 of the master cylinder MC1 (see FIG. 2, the same applies hereinafter) is moved forward by operating the brake lever L1, the hydraulic chamber 14 (see FIG. 2, the same applies hereinafter) of the master cylinder MC1 is compressed by the piston 11. The As shown in FIG. 1, the brake hydraulic pressure generated thereby acts on the inlet port J1 through the pipe H1, as shown in FIG. 1, and the output hydraulic pressure path D1, the inlet valve 2, the wheel hydraulic pressure path E1. Acting on the exit port J2 and acting on the wheel brake F via the pipe H2.
When the brake lever L1 is returned, the piston 11 of the master cylinder MC1 is moved backward, the hydraulic chamber 14 expands, the brake fluid is returned to the hydraulic chamber 14, and the hydraulic chamber 14 passes through the relief port 16 to the oil reserve tank 10A. Inflow. As a result, the wheel brake F returns to the brake hydraulic pressure inoperative state.

  While such normal braking is being performed, the outlet valve 3 is closed without being controlled, so that the brake fluid does not flow out through the outlet valve 3 into the open path Q1.

Further, the open-path valve 30 is in a closed state during normal brake braking. That is, as shown in FIG. 4A, the brake fluid pressure acting on the wheel brake fluid pressure chamber V3 and the master cylinder fluid pressure chamber V4 of the open-circuit valve 30 is basically the same, so the piston 32 Is held at the initial position.
Thus, the valve body 31 is held at the first position where the valve body 31 is closed, and the valve body 31 closes the space between the open path Q1 and the open path Q2. Accordingly, the brake fluid is not returned from the open path Q2 to the master cylinder MC1.

(Anti-lock brake control)
Next, when the brake lever L1 is operated so that the brake fluid pressure is applied to the wheel brake F, if a slip state occurs in the wheel connected to the wheel brake F and the wheel is about to lock, the anti-lock Brake control is performed.
Here, whether or not a slip state has occurred is determined by the control device 6, and when it is determined that a slip state has occurred, the control device 6 performs any one of decompression, pressure increase, and holding. Select a mode.

  In the anti-lock brake control, when the mode for reducing the brake fluid pressure is executed, the inlet valve 2 is closed and the outlet valve 3 is opened. If it does in this way, since the brake fluid which exists in the wheel brake F side rather than the inlet valve 2 will flow out into the open path Q1 from the outlet valve 3, the brake fluid pressure which acted on the wheel brake F will reduce pressure. Become.

When the brake fluid pressure is reduced as described above, if the brake lever L1 continues to be operated, the master cylinder fluid pressure chamber V4 of the open-circuit valve 30 with the inlet valve 2 and the check valve 2a as a boundary. When a differential pressure is generated between the brake fluid pressure acting on the brake fluid pressure and the brake fluid pressure acting on the wheel brake fluid pressure chamber V3, and this becomes the valve opening pressure, as shown in FIG. 32 slides toward one end.
As a result, the protruding portion 330 of the one end side insertion portion 32B of the piston 32 comes into contact with the other end surface 31b of the small diameter portion 31B of the valve body 31, and further, the biasing force of the spring member 315 is applied as shown in FIG. It opposes and pushes the valve body 31 toward one end side.
Then, the valve body 31 moves from the first position to the second position, and the other end surface 31a ′ of the large-diameter portion 31A of the valve body 31 is separated from the step surface 313 and the inflow chamber V1 and the outflow chamber. V2 communicates.

On the other hand, the brake fluid that has flowed out from the outlet valve 3 to the open path Q1 by the pressure reduction control temporarily flows into the reservoir 4 through the open path Q1, and then flows out again to the open path Q1 and flows into the open path valve 30. It flows into the chamber V1.
In the open path valve 30, the valve body 31 is moved from the first position to the second position as described above, and the inflow chamber V1 and the outflow chamber V2 are in communication with each other. The brake fluid that has flowed into the chamber V1 flows into the outflow chamber V2 through the space between the other end surface 31a ′ of the large-diameter portion 31A and the step surface 313, and flows out from the outflow chamber V2 into the open path Q2.

Then, as shown in FIG. 1, the brake fluid that has flowed into the open path Q2 flows into the master cylinder MC1 through the pipe H3 from the open port J3 downstream of the open path Q2, and then the oil reserve tank through the supply oil chamber 11a. Return to 10A.
Thus, at the time of pressure reduction control, the open-circuit valve 30 is automatically opened using the differential pressure generated at the time of pressure reduction control, and the brake fluid released from the outlet valve 3 is preferably returned to the master cylinder MC1. It will be.

  Next, in the antilock brake control, when the holding control for holding the brake fluid pressure applied to the wheel brake F is executed, both the inlet valve 2 and the outlet valve 3 are closed. In this way, the brake fluid is confined in the flow path closed by the inlet valve 2 and the outlet valve 3, so that the brake fluid pressure acting on the wheel brake F is maintained.

  When such holding control is being performed, if the brake lever L1 continues to be operated, the brake fluid pressure of the master cylinder MC1 becomes the brake of the wheel brake F across the inlet valve 2 and the check valve 2a. The pressure becomes higher than the hydraulic pressure, and a differential pressure is generated between the brake hydraulic pressure acting on the master cylinder hydraulic pressure chamber V4 and the brake hydraulic pressure acting on the wheel brake hydraulic pressure chamber V3, and this is the valve opening pressure. When (the urging force of the spring member 315) is reached, the piston 32 slides to the valve body 31 side (one end side) as in the pressure reduction control, and the valve body 31 is opened. In the holding control, since the brake fluid does not flow out from the outlet valve 3, even if the valve body 31 is opened, the brake fluid from the outlet valve 3 is not returned to the master cylinder MC1, but the reservoir 4 When the brake fluid temporarily stored in the storage chamber remains, the brake fluid is pushed out to the open path Q1 by the elastic force of the spring 4a of the reservoir 4, and is supplied to the master cylinder MC1 through the open path valve 30. Will be returned.

  Further, in the antilock brake control, when the pressure increasing control for increasing the brake fluid pressure applied to the wheel brake F is executed, the inlet valve 2 is opened and the outlet valve 3 is closed. In this case, the brake fluid pressure generated in the master cylinder MC1 due to the operation of the brake lever L1 acts on the wheel brake F through the output fluid pressure passage D1, the inlet valve 2, and the wheel fluid pressure passage E1, so that the wheel The brake fluid pressure of the brake F increases.

  When such pressure increase control is being executed, if the brake lever L1 continues to be operated, the brake fluid of the master cylinder MC1 is sent to the wheel brake F via the inlet valve 2, so that the master cylinder The brake fluid pressure of MC1 and the brake fluid pressure of the wheel brake F become the same pressure, the piston 32 is in the initial position, and the valve body 31 is closed. As a result, the space between the open path Q1 and the open path Q2 is closed.

Next, when the operating force of the brake lever L1 is released during the antilock brake control and the brake lever L1 is returned, the antilock brake control is finished, the inlet valve 2 is controlled to open, and the outlet valve 3 is The valve closing control is performed, and the open path valve 30 is closed.
That is, in the open-circuit valve 30, when the brake lever L1 is returned, the brake fluid pressure in the master cylinder MC1 is not generated, so that it acts on the master cylinder fluid pressure chamber V4 and the wheel brake fluid pressure chamber V3. The brake fluid pressure is lost, and the thrust of the piston 32 disappears. As a result, when the piston 32 slides to one end side, the piston 32 is returned to the initial position by the biasing force of the spring member 329, and the pushing action on the valve body 31 is released. As a result, the valve body 31 is returned from the second position to the first position, and the space between the open path Q1 and the open path Q2 is closed (see FIG. 2).

  Then, as shown in FIG. 1, the brake fluid pressure acting on the wheel brake F passes from the wheel fluid pressure passage E1 to the hydraulic chamber 14 via the inlet valve 2 (check valve 2a), the output fluid pressure passage D1, and the pipe H1. To the oil reserve tank 10 </ b> A through the relief port 16. As a result, the wheel brake F returns to the brake hydraulic pressure inoperative state.

Here, when the brake fluid temporarily stored in the storage chamber of the reservoir 4 remains at the end of the antilock brake, the brake fluid is returned to the master cylinder MC1 as follows.
That is, the brake fluid remaining in the reservoir chamber of the reservoir 4 is pushed out to the open path Q1 by the action of the return of the piston 11 and the elastic force of the spring 4a provided in the reservoir 4, and the check valve 5 of the return path T1. Then, the fluid is returned from the output hydraulic pressure path D1 to the hydraulic chamber 14 through the pipe H1, and further returned to the oil reserve tank 10A through the relief port 16.
That is, in this brake control device U, the brake fluid can be returned to the master cylinder MC1 via the check valve 5 by returning the brake lever L1, without having a pump for pumping the brake fluid from the reservoir 4.

According to the brake control device U described above, on the open paths Q1 and Q2, the open path valve 30 that operates using the differential pressure between the brake hydraulic pressure of the master cylinder MC1 and the brake hydraulic pressure of the wheel brake F is provided. Therefore, when a differential pressure between the brake fluid pressure of the master cylinder MC1 and the brake fluid pressure of the wheel brake F is generated, when this becomes the valve opening pressure, the valve 30 for the opening passage is opened to open the opening passage. The gap between Q1 and Q2 can be opened, and when the differential pressure is lost, the open path valve 30 can be closed to block between the open paths Q1 and Q2.
As a result, at the time of pressure reduction control of the anti-lock brake control, the open path valve 30 is opened with the generated differential pressure, and the brake fluid released through the outlet valve 3 is transferred to the master cylinder MC1 through the open paths Q1 and Q2. Can be returned. Therefore, the control time during the pressure reduction control can be made longer than in the case where the brake fluid pressure is reduced only by flowing the brake fluid into the reservoir as in the prior art. Thereby, the degree of freedom of control can be increased.

Further, since the differential pressure is eliminated during normal braking, the open passage valve 30 can be closed to close the open passages Q1 and Q2, and in the unlikely event, the brake fluid is discharged from the outlet valve 3 to the open passage Q1. Even if a situation occurs, the flow from the open path Q1 to the open path Q2 is blocked by the closed open path valve 30 and the brake fluid is prevented from returning to the master cylinder MC1. it can.
Thereby, the certainty of the fail-safe function can be increased.

  In this way, the open-circuit valve 30 is automatically opened by the differential pressure generated during the pressure reduction control of the antilock brake control, and then the open-path valve 30 is automatically closed when the differential pressure disappears. Therefore, for example, compared with the case where the open path is controlled to be opened and closed using a solenoid valve, complicated control is not required, and the open path Q1 and Q2 between the open paths Q1 and Q2 can be easily controlled using differential pressure. Occlusion can be performed easily.

  Further, since no electric power is consumed to open and close the open path valve 30, the brake control device U capable of reducing the power consumption can be obtained.

  Further, when the piston 32 is in the initial position, a gap P serving as a dimension adjustment allowance is formed between the valve body 31 and the piston 32. Therefore, a dimensional tolerance is provided between the valve body 31 and the piston 32. And a sufficient distance can be secured in consideration of assembly tolerances. As a result, the piston 32 does not come into contact with the valve body 31 at the initial position, and the valve body 31 is reliably held at the first position by the spring member 315. Therefore, the closed state between the open paths Q1 and Q2 can be maintained well, and the reliability of the fail-safe function can be increased.

  Moreover, in the said embodiment, although the valve body 31 and the piston 32 were demonstrated as a different body, it is not restricted to this, You may provide these integrally in the cylinder 30a.

  Moreover, in the said embodiment, although the valve body 31 and the piston 32 were arrange | positioned in series in the cylinder 30a, it is not restricted to this, You may arrange | position in parallel.

Further, the front wheel brake system K1 may be provided with interlocking brake means for braking the two wheel brakes F and R by operating the brake lever L1, and the rear wheel brake system K2 is provided with two brake levers L2 by operating the brake lever L2. An interlocking brake means for braking the wheel brakes F and R may be provided.
In addition, a mechanical brake is adopted for the wheel brake R on the rear wheel side, and a branching device and a cylinder device that enable interlocking brake braking of the front and rear wheels are provided, and when the rear wheel brake lever L2 is operated, You may comprise so that the interlocking brake braking of a wheel may be performed.

2 Inlet valve (normally open solenoid valve)
3 Outlet valve (normally closed solenoid valve)
10A Oil reserve tank (tank)
30 Valve for open circuit (normally closed solenoid valve)
30a Cylinder 31 Valve body 32 Piston 315 Spring member (first biasing means)
329 Spring member (second urging means)
F, R Wheel brake K1, K2 Brake system MC1 Master cylinder MC2 Master cylinder P Clearance Q1, Q2 Open path U Brake control device (vehicle brake hydraulic pressure control device)

Claims (4)

In a vehicle brake hydraulic pressure control device that is disposed between a master cylinder and a wheel cylinder of a wheel brake, has a normally open solenoid valve and a normally closed solenoid valve, and can execute antilock brake control.
An open path for connecting the open-air tank provided in the master cylinder and the normally closed solenoid valve to return the working fluid released through the normally closed solenoid valve to the tank;
An open path valve that is provided in the open path and operates using a differential pressure between the brake hydraulic pressure of the master cylinder and the brake hydraulic pressure of the wheel cylinder, and shuts off or opens the open path. A brake fluid pressure control device for a vehicle. The open path valve is a normally closed valve;
A cylinder, and a valve body and a piston arranged in series in the cylinder,
The valve body is
It is movable to a first position for blocking the open path and a second position for opening the open path, and is biased toward the first position by the first biasing means,
The piston is
When a differential pressure is generated between the brake fluid pressure of the master cylinder and the brake fluid pressure of the wheel cylinder, it slides toward the valve body with a thrust using the differential pressure, and the first urging means The vehicular brake hydraulic pressure control device according to claim 1, wherein the valve body is pushed from the first position to the second position against an urging force. The piston is
Via a seal member, a wheel brake fluid pressure chamber where the brake fluid pressure of the wheel cylinder acts on one end surface, and a master cylinder where the brake fluid pressure of the master cylinder acts on the other end surface opposite to the one end surface Separates the hydraulic chamber,
Further, the second biasing means is biased toward the other end surface side,
The first thrust generated by the brake fluid pressure of the master cylinder is
When the second thrust generated by the brake fluid pressure of the wheel cylinder and the resultant force of the urging force by the second urging means are greater than the resultant force, the valve body slides and pushes the valve body. The vehicular brake hydraulic pressure control device according to claim 2. The piston is configured to directly contact the valve body and push the valve body,
A gap serving as a dimension adjustment allowance is formed between the valve body and the piston when the piston is in an initial position before sliding toward the valve body. The brake fluid pressure control device for a vehicle according to claim 2 or claim 3.

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