JPH035336B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention provides an output port of a master cylinder,
A control valve device is installed in each oil path connecting the rear wheel brake, and when the front or rear wheels are about to lock up during braking, the corresponding control valve is closed and the control valve device is closed. The present invention relates to a brake hydraulic control device for a vehicle that reduces pressure on the output side to avoid a locked state.

(2) Prior Art Conventionally, in this type of brake hydraulic control device, when antilock control is performed on each wheel brake, the reaction force accompanying the control is transmitted to the master cylinder side to cause a so-called kickback phenomenon. There are also methods that do not cause the backlash phenomenon.

(3) Problems to be Solved by the Invention The former method has the advantage of allowing the driver to sense through the brake pedal that antilock control is being performed due to the kickback phenomenon; When anti-lock control is applied at the same time, there is a drawback that the reaction force increases and impairs the driver's braking sensation, and in the latter case, the operator does not directly sense that anti-lock control is being performed. There is a drawback that it cannot be done.

Therefore, the present invention causes the kickback phenomenon to occur during antilock control of the rear wheel brakes, which is generally performed relatively frequently, and prevents the kickback phenomenon from occurring during the antilock control of the front wheel brakes, without impairing the braking feeling. It is an object of the present invention to provide a brake hydraulic control device that allows a driver to directly sense that anti-lock control is being performed.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a front control valve device in the oil passage connecting the output port of the master cylinder and the front wheel brake, and A rear control valve device is interposed in each oil path connecting the output port and the rear wheel brake, and the front control valve device is slidable into a front wheel valve case and a cylinder hole of the front wheel valve case. A valve piston is defined between the front wheel valve piston and the cylinder hole of the front wheel valve case, and is connected to the output port and has a constant volume regardless of the sliding position of the front wheel valve piston. A front wheel output that is defined between the front wheel input hydraulic chamber, the front wheel valve piston, and the cylinder hole of the front wheel valve case, is connected to the front wheel brake, and whose volume increases when the front wheel valve piston slides toward one side. A front wheel valve that closes a front wheel valve hole that communicates between a hydraulic chamber and a front wheel input and output hydraulic chamber by sliding the front wheel valve piston in one direction, and opens the front wheel valve hole by sliding the front wheel valve piston in the other direction; and a front wheel operation control device connected to the front wheel valve piston so as to hold the front wheel valve piston at the sliding limit to the other side during normal times, and forcibly slide the front wheel valve piston to the one side when the front wheel is about to lock. , the rear control valve device includes a rear wheel valve case, a rear wheel valve piston slidably fitted into a cylinder hole of the rear wheel valve case, and the rear wheel valve piston and the rear wheel valve piston. A rear wheel input hydraulic chamber is defined between the cylinder holes of the valve case and is connected to the output port, and whose volume decreases when the rear wheel valve piston slides toward one side, and the rear wheel valve piston and the rear wheel. a rear wheel output hydraulic chamber defined between the cylinder holes of the rear wheel valve box, connected to the rear wheel brake, and whose volume increases as the rear wheel valve piston slides toward the one side; and a rear wheel input and output hydraulic chamber. A rear wheel valve that closes a rear wheel valve hole that communicates between hydraulic chambers by sliding the rear wheel valve piston in one direction and opens the rear wheel valve hole by sliding the rear wheel valve piston in the other direction, and a rear wheel valve piston. and a rear wheel operation control device connected to the rear wheel valve piston so as to maintain the valve piston at the sliding limit to the other side during normal times, and forcibly slide the rear wheel to the one side when the rear wheel is about to lock. Features.

(2) Effect When the front wheel is about to lock up, the front wheel operation control device forcibly slides the front wheel valve piston to the one side, so the front wheel valve closes and the volume of the front wheel output hydraulic chamber increases. , it is possible to avoid locking of the front wheels, but at this time, the volume of the input hydraulic pressure chamber for the front wheels does not change, so that the so-called kickback phenomenon does not occur.

On the other hand, when the rear wheel is about to lock up, the rear wheel operation control device forcibly slides the rear wheel valve piston toward the one side, so the rear wheel valve closes and the volume of the rear wheel output hydraulic chamber increases. However, since the volume of the input hydraulic pressure chamber for the rear wheels decreases, a so-called "kickback" phenomenon occurs, and therefore anti-lock control can be performed without impairing the braking feeling. The operator can directly sense that this is occurring.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. M is a known tandem master cylinder operated by a brake pedal Bp, and has independent first and second output ports P ₁ and P ₂ . has.
Bf ₁ and Bf ₂ indicate the left and right front wheel brakes, Br and Br ₂ indicate the left and right rear wheel brakes, respectively, and the left front wheel brake Bf is connected to the first oil path L ₁ extending from the first output port P ₁ . The hydraulic actuation parts of _the front right wheel brake Bf ₂ and _the rear right wheel brake Br ₂ are connected to the second oil passage L ₂ extending from the second output port P ₂ . parts are connected. Therefore, the first and second oil passages L ₁ and L ₂ become so-called X-shaped piping.

A front control valve device Vf is connected to the first and second oil passages L ₁ and L ₂ leading to the left and right front wheel brakes Bf ₁ and Bf ₂ , and also leading to the left and right rear wheel brakes Br ₁ and Br ₂ . Rear control valve devices Vr are respectively installed in the first and second oil passages L ₁ and L ₂ .

The front control valve device Vf has a front wheel valve case 1 fixed to a proper position on the vehicle body. On the left side of this valve case 1 is the upstream side of the first oil passage _L1 (master cylinder side).
A first inlet 21 is connected to the first inlet ₂₁ , and a first outlet ₃₁ is connected to the downstream side (brake side), and a second outlet 31 is provided on the right side to which the upstream side of the second oil passage _L2 is connected. A second outlet 3 ₂ is provided which is connected to the inlet 2 ₂ on the same downstream side. These first inlet 2 ₁ and first outlet 3 ₁ ,
First and second control valves 4 ₁ and 4 ₂ that control communication and isolation between the second inlet _{2 2} and the second outlet 3 ₂ are arranged in parallel in the front wheel valve box 1 .

Since both control valves 4 ₁ and 4 ₂ have the same configuration, the first
The configuration of only the control valve ₄₁ will be explained.

The front wheel valve box 1 has a cylinder hole 5 whose rear end is closed.
A front wheel valve piston 6 is slidably connected to the front wheel valve piston 6 via a pair of front and rear seal members 7, 7'. This valve piston 6 includes a seal member 7,
7' has a wide annular outer circumferential groove 8 in the middle part thereof, and this groove 8 defines a constant volume front wheel input hydraulic chamber 9 in the cylinder hole 5 that communicates with the first inlet ₂₁ . . Further, the rear end of the front wheel valve piston 6 and the closed end wall of the cylinder hole 5 define a variable volume front wheel output hydraulic chamber 10 in communication with the first outlet 3 ₁ in the cylinder hole 5 . Front wheel valve piston 6
has a valve seat member 6b that protrudes from the rear end surface and comes into contact with the closed end wall of the cylinder hole 5, and a valve chamber 11 is provided inside the valve seat member 6b. This valve chamber 11
communicates with the front wheel input hydraulic pressure chamber 9 via the through hole 12, and also communicates with the front wheel output hydraulic pressure chamber 10 via the valve hole 13 of the valve seat member 6b. The valve chamber 11 accommodates a spherical front wheel valve 14 that is seated on the valve seat member 6b and can close the valve hole 13, and a valve closing spring 15 that biases the valve toward the closing side. The front wheel valve 14 is integrally provided with a valve opening rod 16 that passes through the valve hole 13 loosely, and when the front wheel valve piston 6 is located at the backward limit with the valve seat member 6b abutting the closed end wall of the cylinder hole 5. The valve opening rod 16 is pushed forward from the closed end wall to open the front wheel valve 14.

At the front of the front wheel valve box 1, a spring chamber 17 common to both control valves 4 ₁ and 4 ₂ is defined by a cover 1a. The front wheel valve pistons 6, 6 of both control valves 4 ₁ , 4 ₂ have respective piston rods 6 a, 6 a extending to their spring chambers 17, and both ends are swingably connected to the front ends of these piston rods 6 a, 6 a. A spring 19 that presses the center portion of the lever 18 to hold each front wheel valve piston 6, 6 at the rearward limit is housed therein. This spring 19 is given a set load sufficient to keep the front wheel valve pistons 6, 6 at the backward limit even if the pressure in the left and right front wheel output hydraulic chambers 10, 10 increases.

Further, the front wheel valve case 1 is provided with a cylinder hole 20 parallel to the left and right cylinder holes 5, 5 in the middle part thereof and having a closed rear end.
A control piston 21 that abuts on the central portion of the piston 8 is slidably engaged with the piston 21 . The control piston 21 defines a control hydraulic chamber 22 between the control piston 21 and the rear end wall of the cylinder hole 20 .

This control hydraulic chamber 22 is connected to an oil tank 24 and a pressure accumulator 25 via a front solenoid valve 23f, and when this front solenoid valve 23f is demagnetized, the oil tank 24
4, and when excited, it communicates with the pressure accumulator 25. Pressure oil discharged from a hydraulic pump 27 driven by an electric motor 26 is stored in the pressure accumulator 25 .

The rear control valve device Vr has a rear wheel valve case 31 fixed to a proper position on the vehicle body. On the right side of this valve box 31 is the upstream side of the first oil passage _L1 (master cylinder side).
A first inlet 32 ₁ is connected to the first inlet 32 1 and a first outlet 33 ₁ is connected to the downstream side (brake side).
Further, a second inlet 32 ₂ connected to the upstream side of the second oil passage L ₂ and a second outlet 33 ₂ connected to the downstream side of the second oil passage L 2 are provided on the left side surface. First and second control valves 34 ₁ and 34 2 for controlling communication and isolation between the first inlet 32 ₁ and the first outlet 33 1 and between the second inlet _{32 2} and the second outlet _{33 2 are} for rear wheels. They are arranged in parallel within the valve box 31.

Since both control valves 34 ₁ and 34 ₂ have the same configuration,
The configuration of only the first control valve ₃₄₁ will be explained.

A cylinder hole 35 whose rear end is closed is formed in the rear wheel valve box 31, and a rear wheel valve piston 36 is slid into this through a seal member 37.
The valve piston 36 has a piston rod 36a projecting from its front end surface and a valve seat member 36b projecting from its rear end surface.
The middle part of a is a bearing 38 fitted into the rear wheel valve box 31.
is slidably supported via a seal member 39. Therefore, the rear wheel valve piston 36 is connected to the bearing 3.
8, a variable volume rear wheel input hydraulic chamber 40 communicating with the first inlet ₃₂₁ , and a cylinder hole 5
A rear wheel output hydraulic chamber 41 having a variable volume and communicating with the first outlet 33 ₁ is defined between the closed end wall and the closed end wall of the rear wheel.

In addition, a valve chamber 42 is provided in the rear wheel valve piston 36.
The valve chamber 42 communicates with the rear wheel input hydraulic pressure chamber 40 through the through hole 43 of the piston rod 36a, and communicates with the rear wheel output hydraulic chamber 40 through the valve hole 44 of the valve seat member 36b. It also communicates with 41. The valve chamber 42 accommodates a spherical rear wheel valve 45 that is seated on the valve seat member 36b and can close the valve hole 44, and a valve closing spring 46 that biases the valve toward the closing side. The rear wheel valve 45 is integrally equipped with a valve opening rod 47 that loosely passes through the valve hole 44, and is connected to the rear wheel valve piston 36.
However, when the valve seat member 36b is brought into contact with the closed end wall of the cylinder hole 35 and is located at the backward limit, the valve opening rod 47
is pushed forward from the closed end wall to open the rear wheel valve 45.

A spring chamber 49 that accommodates a pressure regulating spring 48 is defined by a cover 31a at the front of the rear wheel valve box 31. In the chamber 49, the first and second control valves 34
Two piston rods 36a, 36a, ₁ , 34 ₂
Both ends of a lever 50 are swingably connected to the front end of the lever 50, and the pressure regulating spring 48 is attached to the center of the lever 50.
A resilient force is applied so as to press each rear wheel valve piston 36, 36 to the backward limit.

Further, the rear wheel valve box 31 is provided with a cylinder hole 51 which is parallel to the two cylinder holes 35, 35 and whose rear end is closed, in the middle part of the two cylinder holes 35, 35, and which comes into contact with the center part of the lever 50. Control piston 52 is slid together. Thus, the control piston 52 defines a control hydraulic chamber 53 between the control piston 52 and the rear end wall of the cylinder hole 51.

This control hydraulic chamber 53 is connected to the oil tank 24 and the pressure accumulator 25 via the empty solenoid valve 23r, and communicates with the oil tank 24 when the rear solenoid valve 23r is demagnetized and is energized. It communicates with the pressure accumulator 25.

A control circuit 54 is provided for controlling the front and rear solenoid valves 23f, 23r. This circuit 54
is the first front wheel that detects the rotational speed of the left and right front wheels.
and when it receives signals from the second wheel speed sensors 55f ₁ and 55f ₂ and determines that the front wheels are about to become locked, it issues an excitation signal to the front electromagnetic valve 23f;
In addition, the rear first sensor detects the rotational speed of the left and right rear wheels.
When it receives signals from the second wheel speed sensors 55r ₁ and 55r ₂ and determines that the rear wheels are about to become locked, it issues an excitation signal to the rear solenoid valve 23r. Furthermore, this control circuit 54 receives a signal from a pressure sensor 56 that detects the oil pressure in a hydraulic circuit connected to the pressure accumulator 25, and when it determines that a predetermined oil pressure has been stored in the pressure accumulator 25, it causes the electric motor 26 to stop. emit a signal.

The control circuit 54, the solenoid valve 23f, the control piston 21, and the spring 19 cooperate with each other to constitute the front wheel operation control device Cf of the present invention. 52
The spring 48 and the spring 48 cooperate with each other to constitute the rear wheel operation control device Cr of the present invention.

Next, to explain the operation of this embodiment, when the vehicle is running, the brake pedal Bp is depressed to operate the master cylinder M, and the first and second output ports P ₁ ,
If hydraulic pressure is output from each of _P2 , the output hydraulic pressure of the first output port _P1 will be the input hydraulic pressure for the front wheels of the first control valve ₄₁ in the front control valve device Vf from the upstream part of the first oil path _L1 . It sequentially passes through the chamber 9, the valve chamber 11, the valve hole 13, and the front wheel output hydraulic chamber 10, and then the first oil passage.
It is transmitted to the left front wheel brake Bf ₁ via the downstream part of L ₁ ,
Also, from the upstream part of the first oil passage _L1 to the rear control valve device Vr
Rear wheel input hydraulic chamber 4 of the first control valve 34 ₁ in
0, valve chamber 42, valve hole 44 and rear wheel output hydraulic chamber 4
1 sequentially, and is further transmitted to the right rear wheel brake Br ₂ via the downstream part of the first oil passage L ₁ , and operates these brakes Bf ₁ and Br ₂ . On the other hand, the second output port
The output oil pressure of _P2 is from the upstream part of the second oil passage _L2 to the front wheel input oil pressure chamber 9, valve chamber 11, valve hole 13, and front wheel output oil pressure of the _second control valve 42 in the front control valve device Vf. The transmission is transmitted sequentially through the chamber 10 and further through the downstream part of the second oil passage L ₂ to the right front wheel brake Bf ₂ , and from the upstream part of the second oil passage L ₂ to the second control valve 34 ₂ in the rear control valve device Vr. It sequentially passes through the rear wheel input hydraulic chamber 40, the valve chamber 42, the valve hole 44, and the rear wheel output hydraulic chamber 41, and is further transmitted to the left rear wheel brake _Br1 via the downstream part of the second oil passage _L2 . , these brakes Bf ₂ ,
Activate Br ₁ .

As long as the front and rear wheels are not locked, the first and second control valves 4 ₁ and 4 ₂ of the front control valve device Vf are held open by the spring 19, so that the front wheel brakes Bf ₁ and Bf _{2 are} kept open. The working oil pressure always increases with the output oil pressure of the first and second output ports P ₁ and P ₂ , but
The working oil pressure of the rear wheel brakes Br ₁ and Br ₂ is changed to the first and second control valves 34 of the rear control valve device Vr after the output oil pressures of the first and second output ports P ₁ and P ₂ exceed a predetermined value. ₁ and 34 ₂ as follows.

First, due to the increase in the output oil pressure of the first output port _P1 , the first control valve ₃₄₁ is turned on and the output oil pressure chambers 40, 4 are turned on.
When the oil pressure of No. 1 reaches a predetermined value, the pressure exerts a forward pressing force on the rear wheel valve piston 36 (a force obtained by multiplying the cross-sectional area of the piston rod 36a by the oil pressure).
However, the valve opening force of the pressure regulating spring 48 on the rear wheel valve piston 36 (the pressure regulating spring 48 applies a valve opening force to the two left and right rear wheel valve pistons 36, 36 via the lever 50, One-half of the set load of the pressure regulating spring 48 becomes the valve opening force for one rear wheel valve piston 36.) When the lever 50 is slightly tilted, the rear wheel valve piston 36 is moved forward, the valve seat member 36b is engaged with the rear wheel valve 45, the valve hole 44 is closed, and communication between the input and output hydraulic chambers 40 and 41 is cut off. Thereafter, the output oil pressure of the first output port P ₁ further increases, and the pressure of the oil pressure in the rear wheel input oil pressure chamber 40 is applied to the rear wheel valve piston 36 (the rear wheel valve piston 36 has a large diameter portion). A force obtained by multiplying the difference between the cross-sectional area and the cross-sectional area of the piston rod 36a by the hydraulic pressure in the rear wheel input hydraulic pressure chamber 40 is the force that increases the hydraulic pressure in the rear wheel output hydraulic chamber 41.
The rear wheel valve piston 36 is pushed back to overcome the forward pressing force (the force obtained by multiplying the cross-sectional area of the large diameter portion of the rear wheel valve piston 36 by the hydraulic pressure of the rear wheel output hydraulic chamber 41). Since the wheel valve 45 is separated from the valve seat member 36b and the two hydraulic chambers 40 and 41 are communicated again, the pressure in the rear wheel output hydraulic chamber 41 is increased.
The forward pressing force of the first hydraulic pressure on the rear wheel valve piston 36 increases immediately, and the rear wheel valve piston 36 is moved forward again to open both hydraulic chambers 40,
41 will be cut off. From now on, the first output port
A similar action is repeated as the output oil pressure of _P1 increases, and as a result, the output oil pressure of the first output port _P1 is proportionally reduced in pressure and transmitted to the right rear wheel brake _Br2 .

Furthermore, when the output oil pressure of the second output port P ₂ rises above a predetermined value, the second control valve 34 ₂ operates in the same manner as the first control valve 34 ₁ , and the output oil pressure of the second output port P ₂ increases. It is clear that the pressure is proportionally reduced and transmitted to the left rear wheel brake Br ₁ .

In the above, the pressure reduction start pressure of each control valve 34 ₁ , 34 ₂ is determined by the cross-sectional area of each piston rod 36a and the set load of the pressure regulating spring 48, and the pressure reduction ratio is determined by the cross-sectional area of each piston rod 36a and the set load of the pressure regulating spring 48. The difference between the area and the cross-sectional area of the piston rod 36a,
It is determined by the ratio to the cross-sectional area of the piston rod 36a.

During this braking, when the rear wheels are about to lock up, the control circuit 54 issues an excitation signal to the rear solenoid valve 23r, so the solenoid valve 23r is excited and switched to a position where the pressure accumulator 25 and the control hydraulic chamber 53 communicate with each other. ,
The hydraulic pressure of the pressure accumulator 25 is supplied to the control hydraulic chamber 53. Then, in response to the oil pressure, the control piston 52
is operated forward and both control valves 3 are operated via lever 50.
4 ₁ , 34 ₂ The rear wheel valve pistons 36, 36 are moved forward against the force of the pressure regulating spring 48, and each rear wheel valve 45, 45 is closed, and the rear wheel valve pistons 36, 36 to increase the volume of each rear wheel output hydraulic chamber 41, 41 and reduce the pressure in these chambers, the rear wheel brakes Br ₁ ,
The braking force of Br ₂ is weakened and a lock condition is avoided. On the other hand, in each rear wheel input hydraulic chamber 40, 40, the volume is reduced and the pressure increases due to the advancement of the rear wheel valve pistons 36, 36, and the increased pressure is transmitted to the master cylinder M side as a reaction force, that is, a kickback phenomenon occurs. occurs. Therefore, the driver can sense this reaction force through the brake pedal Bp and perceive that antilock control is being performed.

If the lock condition of the rear wheels is avoided, the control circuit 5
4 stops the excitation signal, so the rear solenoid valve 23r
is demagnetized and returns to its original position, and the hydraulic pressure in the control hydraulic chamber 53 is released to the oil tank 24. Therefore, since the control piston 52 stops operating, each control valve 34 ₁ , 34 ₂ is returned to its normal operating state, and the braking force of the rear wheel brakes Br ₁ , Br ₂ is restored.

Furthermore, when the front wheels are about to lock up during braking, the control circuit 54 sends an excitation signal to the front solenoid valve 23f, so the front solenoid valve 23f is energized and brought into communication with the pressure accumulator 25 and the control hydraulic chamber 22. As a result, the hydraulic pressure in the pressure accumulator 25 is supplied to the control hydraulic chamber 22. Then, in response to the oil pressure, the control piston 2
1 operates forward, and the front wheel valve pistons 6, 6 of both control valves 4 ₁ , 4 ₁ are moved by the spring 1 via the lever 18.
Move it forward against the force of 9, and press the valve 1 for each front wheel.
The front wheel brakes Bf ₁ , Bf ₂ braking force is weakened and a lock condition is avoided. Even with the forward movement of the front wheel valve pistons 6, 6 as described above, since the front wheel input hydraulic chambers 9, 9 have a constant volume as described above, there is no change in volume, and therefore, there is no pressure increase. No knockback phenomenon occurs.

If the front wheel lock phenomenon is avoided, the control circuit 5
4 stops the excitation signal, so the front solenoid valve 23f
is demagnetized and returns to its original position, and the hydraulic pressure in the control hydraulic chamber 22 is released to the oil tank 24. Therefore, the control piston 21 stops operating, so each control valve 4 ₁ , 4 ₂ is returned to the open state, and the front wheel brake is turned off.
Restores the braking force of Bf ₁ and Bf ₂ .

C. Effects of the Invention As described above, according to the present invention, a kickback phenomenon occurs during antilock control of rear wheel brakes, but a kickback phenomenon does not occur during antilock control of front wheel brakes, and therefore, without impairing the braking feeling. The driver can directly sense that anti-lock control is being performed, and in particular, since anti-lock control is generally performed more frequently on rear wheel brakes than on front wheel brakes, it is possible to directly sense that anti-lock control is being performed. Leakage is virtually non-existent.

[Brief explanation of the drawing]

The drawing is a hydraulic circuit diagram of an automobile braking system to which an embodiment of the present invention is applied. Bf ₁ , Bf ₂ ...Left, right front wheel brake, Br ₁ , Br ₂
...Left and right rear wheel brakes, Cf, Cr...Front and rear wheel operation control device, M...Master cylinder, P ₁ ,
P ₂ ...1st and 2nd output ports, Vf, Vr...front,
Rear control valve device, 1... Valve box for front wheels, 5... Cylinder hole, 6... Valve piston for front wheels, 9... Input hydraulic chamber for front wheels, 10... Input hydraulic chamber for front wheels, 1
3... Valve hole for front wheel, 14... Valve for front wheel, 31
... Valve box for rear wheel, 35 ... Cylinder hole, 36 ...
Rear wheel valve piston, 40... Rear wheel input hydraulic chamber, 41... Rear wheel output hydraulic chamber, 44... Rear wheel valve hole, 45... Rear wheel valve.

Claims (1)

[Claims] 1. A front control valve device Vf is connected to the oil passages L ₁ and L ₂ connecting between the output ports P ₁ and P ₂ of the master cylinder M and the front wheel brakes Bf ₁ and Bf ₂ , and the output ports P ₁ and
Oil path L ₁ connecting P ₂ and rear wheel brakes Br ₁ , Br ₂ ,
A rear control valve device Vr is interposed in each of _L2 , and the front control valve device Vf includes a front wheel valve box 1 and a front wheel slidably fitted into the cylinder hole 5 of the front wheel valve box 1. The valve piston 6 for the front wheel is defined between the valve piston 6 for the front wheel and the cylinder hole 5 of the valve case 1 for the front wheel, is connected to the output ports P ₁ and P ₂ , and is related to the sliding position of the valve piston 6 for the front wheel. A front wheel input hydraulic chamber 9 having a constant volume and a front wheel valve piston 6 is also defined between the front wheel valve piston 6 and the cylinder hole 5 of the front wheel valve box 1, and is connected to the front wheel brakes Bf ₁ and Bf ₂ . The front wheel valve hole 13, which communicates between the front wheel output hydraulic chamber 10 whose volume increases when the front wheel valve piston 6 is slid to one side, and the front wheel input and output hydraulic chambers 9 and 10, is moved to the front wheel valve piston 6 by sliding it toward the one side. The front wheel valve 14, which closes when the valve moves and opens when it slides toward the other side, and the front wheel valve piston 6 are held at the sliding limit to the other side during normal times, and when the front wheels are about to lock, they are moved to the one side. The rear control valve device Vr includes a front wheel operation control device Cf connected to the front wheel valve piston 6 for forced sliding, and the rear control valve device Vr includes a rear wheel valve box 31 and a rear wheel valve box 3.
The rear wheel valve piston 36 is slidably fitted into the cylinder hole 35 of the rear wheel valve piston 36, and the output port _P1 is defined between the rear wheel valve piston 36 and the cylinder hole 35 of the rear wheel valve box 31. , P ₂ and whose volume decreases as the rear wheel valve piston 36 slides toward one side, and the rear wheel valve piston 36 and the cylinder hole of the rear wheel valve box 31. The rear wheel brake is defined between 35
A rear wheel output hydraulic chamber 41 that is connected to Br ₁ and Br ₂ and whose volume increases as the rear wheel valve piston 36 slides toward the one, and a rear wheel input and output hydraulic chamber 4.
A rear wheel valve 4 that closes a rear wheel valve hole 44 that communicates between 0 and 41 by sliding the rear wheel valve piston 36 in one direction, and opens the rear wheel valve hole 44 by sliding the rear wheel valve piston 36 in the other direction.
5, the rear wheel valve piston 36 is connected to the rear wheel valve piston 45 so as to hold the rear wheel valve piston 36 at the sliding limit to the other side during normal times, and forcefully slide the rear wheel valve piston 36 to the one side when the rear wheel is about to lock. A brake hydraulic control device for a vehicle, comprising a rear wheel operation control device Cr.