JPH021703B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake hydraulic control valve device for a vehicle, which supplies a hydraulic pressure lower than that of a front brake as the rear brake hydraulic pressure.

As this type of brake hydraulic control valve device, a valve case is interposed in the oil passage connecting between the output port of the master cylinder and the rear wheel brake, and the output hydraulic pressure of the output port is connected to the rear wheel brake in this valve case. A pressure reducing valve that can proportionally reduce the pressure and transmit it, and a pressure regulating spring that biases the pressure reducing valve in the opening direction and determines the starting pressure for the pressure reduction are known. According to this brake hydraulic control valve device, when a braking input of a certain value or more is applied, the front wheel brake is applied strongly to the front wheel on the side where the downward load of the vehicle body increases, and the front wheel brake is applied strongly to the front wheel on the side where the downward load is decreased. The advantage is that the rear wheel brakes can be operated weakly to achieve more efficient braking.

However, even if such a brake hydraulic control valve device is used, when the braking input is excessive or the road surface conditions are poor, the rear wheels may become locked and the braking efficiency may decrease.

Therefore, the present invention is capable of exhibiting the anti-lock function without impairing the above-mentioned advantages, and also prevents the so-called kickback phenomenon in which the control hydraulic pressure is transmitted from the pressure reducing valve side to the master cylinder side during anti-lock control. It is an object of the present invention to provide a simple and effective brake hydraulic control valve device.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. M is a known tandem type master cylinder operated by a brake pedal Bp and has independent first and second output ports P ₁ and P ₂ .
Bf ₁ and Bf ₂ indicate left and right front wheel brakes, Br ₁ and Br ₂ indicate left and right rear wheel brakes, respectively, and the left front wheel brake is connected to the first oil passage L ₁ extending from the first output port P ₁ . The hydraulic operating parts of Bf ₁ and the right rear wheel brake Br ₂ are connected, and the hydraulic pressures of the right front wheel brake Bf ₂ and the left rear wheel brake Br ₁ are connected to the second oil passage L ₂ extending from the second output port P ₂ . The actuating part is connected. Therefore, the first and second oil passages L ₁ and L ₂ become so-called X-shaped piping. And left and right rear wheel brakes Br ₁ , Br ₂
A brake hydraulic pressure control valve device V of the present invention is installed in the first and second oil passages L ₁ and L ₂ leading to the brake hydraulic pressure control valve device V of the present invention.

The brake hydraulic control valve device V has a valve case 1 fixed to a proper position on the vehicle body. The right side of this valve box 1 has a first inlet ₂₁ connected to the upstream side (master cylinder side) of the first oil passage _L1 and the same downstream side (brake side).
A first outlet ₃₁ connected to the second oil passage L2 is provided on the left side, and a second inlet ₂₂ connected to the upstream side of the second oil passage _L2 and a second outlet ₃₂ connected to the downstream side of the second oil passage L2 are provided on the left side. provided. These first inlet 2 ₁ , first outlet 3 ₁ , second
First and second pressure reducing valves _{4 1} and 4 ₂ are arranged in parallel within the valve box 1 to control communication and isolation between the inlet 2 2 and the second outlet 3 ₂ .

Both pressure reducing valves 4 ₁ and 4 ₂ have the same configuration, so the first
The configuration of only the pressure reducing valve ₄₁ will be explained.

The valve case 1 is provided with stepped cylinder holes consisting of a large-diameter cylinder hole 5a at the front, a small-diameter cylinder hole 5b at the middle, and a large-diameter cylinder hole 5c at the rear.
A bearing 8 is fitted into the front cylinder hole 5a, a pressure receiving piston 6 is slid into the intermediate cylinder hole 5b via a seal member 7, and a stopper 1a that restricts the backward limit of the piston 6 is fitted into the cylinder hole 5b. It is provided to protrude from the inner circumferential wall of 5b. The control piston 22 is slidably engaged with the rear cylinder hole 5c via a seal member 32, and a spring 33 that springs the piston 22 forward is accommodated. The control piston 22 is normally held at its forward limit, where it contacts the front end wall of the cylinder hole 5c, by the elastic force of the spring 33.

The pressure receiving piston 6 has a piston rod 6a projecting from its front end surface and a valve seat member 6b projecting from its rear end surface, and the intermediate portion of the piston rod 6a is slidably attached to the bearing 8 via a seal member 9. supported. Thus, in the cylinder hole 5b, the pressure receiving piston 6 defines a front input hydraulic chamber 10 communicating with the first inlet ₂₁ between the pressure receiving piston 6 and the bearing 8,
Also between the control piston 22 and the first outlet 3 ₁
A rear output hydraulic chamber 11 is defined in communication with the rear output hydraulic pressure chamber 11 .

Further, a valve chamber 12 is formed in the pressure receiving piston 6, and this valve chamber 12 communicates with an input hydraulic pressure chamber 10 via a through hole 13 of the piston rod 6a, and communicates with the input hydraulic pressure chamber 10 via a valve hole 14 of the valve seat member 6b. Output hydraulic chamber 11
Also communicates with The valve chamber 12 accommodates a spherical valve 15 that is seated on the valve seat member 6b and can close the valve hole 14, and a valve closing spring 16 that biases the valve toward the closing side. The valve 15 is integrally equipped with a valve opening rod 17 that passes through the valve hole 14 loosely, and when the pressure receiving piston 6 is located at the retraction limit, the valve opening rod 17 is connected to the control piston 2.
2 to open the valve 15.

A spring chamber 19 that accommodates the pressure regulating spring 18 is defined by a cover 34 at the front of the valve case 1 . The room 19
, both ends of a lever 20 are swingably connected to the front ends of the two piston rods 6a and 6a of the first and second pressure reducing valves 4 ₁ and 4 ₂ , and the pressure regulating spring 18 is attached to the center of the lever 20 . A resilient force is applied so as to press each pressure receiving piston 6, 6 to the retraction limit.

The rear end of the rear cylinder hole 5c is closed by a screw plug 35, and this screw plug 35 is connected to the control piston 22.
A control hydraulic chamber 23 is defined between the two.

Each control hydraulic chamber 2 of the first and second pressure reducing valves 4 ₁ , 4 ₂
3 are both connected to an oil tank 25 and a pressure accumulator 26 via a solenoid valve 24. When the solenoid valve 24 is demagnetized, it communicates with the pressure accumulator 26, and when it is energized, it communicates with the oil tank 25.
It has become connected to 5. The pressure accumulator 26 includes a hydraulic pump 28 driven by an electric motor 27.
of discharged oil is stored.

A control circuit 29 is provided to control the electromagnetic valve 24. This circuit 29 includes first and second wheel speed sensors 3 that detect the rotational speeds of the left and right rear wheels.
When it receives the signals from 0 ₁ and 30 ₂ and determines that the rear wheels are about to become locked, it issues an excitation signal to the solenoid valve 24. Further, this circuit 29 is connected to the pressure accumulator 2
6, the electric motor 27 receives a signal from the pressure sensor 31 that detects the oil pressure in the hydraulic circuit connected to the electric motor 27.
issue a stop signal.

Next, to explain the operation of this embodiment, when the master cylinder M is actuated by depressing the brake pedal Bp while the vehicle is running, hydraulic pressure is output from the first and second output ports P ₁ and P ₂ respectively. , the output oil pressure of the first output port P ₁ passes through the first oil path L ₁ to the left front wheel brake Bf ₁ , and also to the upstream part of the first oil path L ₁ , the input oil pressure chamber 10 of the first pressure reducing valve 4 ₁ , and the valve It is transmitted to the right rear wheel brake Br ₂ through the chamber 12, the valve hole 14, the output hydraulic chamber 11, and the downstream part of the first oil path L ₁ to operate these. On the other hand, the output oil pressure of the second output port _P2 is sent to the right front wheel brake _Bf2 via the second oil passage _L2 .
, and the left side after passing through the upstream part of the second oil passage _L2 , the input hydraulic chamber 10, the valve chamber ₁₂ , the valve hole 14, the output hydraulic chamber 11, and the downstream part of the second oil passage _L2 of the second pressure reducing valve 42. The signal is transmitted to the rear wheel brake Br ₁ to operate these.

On the other hand, since the solenoid valve 24 is demagnetized during normal times, it introduces the hydraulic pressure of the pressure accumulator 26 into the control hydraulic chamber 23 . Therefore, the hydraulic pressure of the pressure accumulator 26 is the output hydraulic pressure chamber 11.
Therefore, as long as oil pressure is introduced into the control oil pressure chamber 23, no matter how the oil pressure in the output oil pressure chamber 11 increases, the control piston 22 is set to be larger than the maximum oil pressure in the control oil pressure chamber 23. It will not be pushed back to the forward limit shown in the figure by the hydraulic pressure.

The hydraulic pressure of the front wheel brakes Bf ₁ and Bf ₂ is always the first
The working oil pressure of the rear wheel brakes Br _{1 and Br 2 increases} with the output oil pressure of the first and second output ports P ₁ and P ₂ at a predetermined level. After exceeding the value, the first and second pressure reducing valves 4 ₁ ,
4 ₂ is controlled as follows.

First, due to the increase in the output oil pressure of the first output port _P1 , the first pressure reducing valve ₄₁ is turned on and the output oil pressure chambers 10 and 11 are turned on.
When the hydraulic pressure reaches a predetermined value, the forward pressing force of the hydraulic pressure on the pressure receiving piston 6 (piston rod 6
The force obtained by multiplying the cross-sectional area of a by the hydraulic pressure is the force that is applied to the pressure regulating spring 18
The valve opening force on the pressure receiving piston 6 (pressure regulating spring 18
applies a valve opening force to the two left and right pressure receiving pistons 6, 6 via the lever 20, so one-half of the set load of the pressure regulating spring 18 is the valve opening force to one pressure receiving piston 6. Become. ), the pressure receiving piston 6 is moved forward while slightly tilting the lever 20, the valve seat member 6b is engaged with the valve 15, and the valve hole 14 is closed. 11 will be cut off. Thereafter, the output oil pressure of the first output port _P1 further increases, and the rearward pressing force of the oil pressure of the input oil pressure chamber 10 on the pressure receiving piston 6 (the cross-sectional area of the large diameter portion of the pressure receiving piston 6 and the cross-sectional area of the piston rod 6a) (the difference between The pressure-receiving piston 6 is pushed back to separate the valve 15 from the valve seat member 6b, and the two hydraulic chambers 10 and 11 are communicated again, thereby increasing the pressure in the output hydraulic chamber 11. As a result, the forward pressing force of the hydraulic pressure of the output hydraulic chamber 11 on the pressure receiving piston 6 increases immediately, and the pressure receiving piston 6 is moved forward again to close both hydraulic chambers 10 and 11.
cut off communication between After that, the first output port P ₁
The same action is repeated as the output oil pressure increases,
As a result, the output hydraulic pressure of the first output port _P1 is proportionally reduced in pressure and transmitted to the right rear wheel brake _Br2 .

Further, when the output oil pressure of the second output port _P2 increases to a predetermined value or more, the second pressure reducing valve ₄₂ operates in the same manner as the first pressure reducing valve ₄₁ , and the output oil pressure of the second output port _P2 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 pressure reducing valve 4 ₁ and 4 ₂ is determined by the cross-sectional area of each piston rod 6a and the set load of the pressure regulating spring 18, and the pressure reduction ratio is determined by the cross-sectional area of the large diameter portion of the pressure receiving piston 6 and the piston rod. 6a and the piston rod 6a.
It is determined by the ratio of the cross-sectional area of

During this braking, when the rear wheels are about to lock up, the control circuit 29 issues an excitation signal to the solenoid valve 24, so the solenoid valve 24 is excited and switched to a position where the oil tank 25 and the control hydraulic chamber 23 communicate with each other. The hydraulic pressure in the control hydraulic chamber 23 is released to the oil tank 25. Then, the hydraulic pressure in the output hydraulic chamber 11 causes the control piston 22 to retreat against the elastic force of the spring 33, so that the valve opening rod 17 is released from the pressing force of the control piston 22, allowing the valve 15 to close. Inevitably, the pressure in the output hydraulic chamber 11 decreases, and therefore the rear wheel brake
The braking forces of Br ₁ and Br ₂ are weakened and a locked state is avoided. During this depressurization of the output hydraulic chamber 11, the pressure receiving piston 6 is held by the hydraulic pressure of the input hydraulic chamber 10 at the contact position with the stopper 1a, that is, at the backward limit.

If the lock state is avoided, the control circuit 29 stops the excitation signal, so the solenoid valve 24 is demagnetized and returns to its original position, and the hydraulic pressure in the pressure accumulator 26 is introduced into the control hydraulic chamber 23 again. Therefore, the control piston 22 is pushed to the forward limit again, so that each pressure reducing valve 4
₁ and 4 ₂ to the normal operating state, and the braking force of the rear wheel brakes Br ₁ and Br ₂ is restored.

As described above, according to the present invention, the hydraulic pressure from the hydraulic source is introduced into the valve case housing the pressure reducing valve and the pressure regulating spring during normal times, and when the rear wheels are about to enter the lock state, the hydraulic pressure is released to the oil tank. a control hydraulic chamber, which is configured to hold the pressure reducing valve at the forward limit that can open the pressure reducing valve when receiving the hydraulic pressure of the control hydraulic chamber, and close the pressure reducing valve when the pressure reducing valve is released from the hydraulic pressure; A control piston is provided that moves backward to reduce the pressure on the output side of the brake, so when the rear wheels are about to lock up, the rear wheel brake's hydraulic pressure is reduced by the backward movement of the control piston to avoid the locking phenomenon. Moreover, during this anti-lock control,
Since the pressure reducing valve is held at the retraction limit by the output hydraulic pressure of the master cylinder, no kickback phenomenon occurs. In addition, the anti-lock function can be provided by simply adding a control piston to a conventional brake hydraulic control device, so the configuration is simple, and by adding this control piston,
The original advantages of this type of brake hydraulic control valve device are not impaired.

[Brief explanation of drawings]

The drawing is a brake hydraulic circuit diagram for an automobile equipped with a control valve device according to an embodiment of the present invention. Br ₁ , Br ₂ ... Left and right rear wheel brakes, L ₁ , L ₂ ...
...First and second oil passages, M...Master cylinder, P ₁ ,
P ₂ ...First and second output ports, V...Brake hydraulic control valve device, 1...Valve box, 4 ₁ , 4 ₂ ...First and second pressure reducing valves, 6...Pressure receiving piston, 6a... …
Piston rod, 6b... Valve seat member, 10... Input hydraulic chamber, 11... Output hydraulic chamber, 12... Valve chamber,
14... Valve hole, 15... Valve, 17... Valve opening rod, 18... Pressure regulating spring, 22... Control piston,
23... Control hydraulic chamber, 24... Solenoid valve, 25...
Oil tank, 26...Pressure accumulator as a hydraulic source, 28
... Hydraulic pump, 29 ... Control circuit, 30 ₁ , 3
0 ₂ ...First and second wheel speed sensors.

Claims (1)

[Claims] 1 A valve case is interposed in the oil passage connecting between the output port of the master cylinder and the rear wheel brake, and the output hydraulic pressure of the output port is proportionally reduced in pressure and transmitted to the rear wheel brake to the valve case. In the brake hydraulic control valve device for a vehicle, the brake hydraulic pressure control valve device for a vehicle is provided with a pressure reducing valve that can be used as There is a control oil pressure chamber into which oil pressure from the source is introduced, and when the rear wheels are about to enter a lock state, the oil pressure is released to the oil tank, and when receiving oil pressure from this control oil pressure chamber, the pressure reducing valve is opened. and a control piston that is held at the forward limit to obtain the hydraulic pressure and, when released from the hydraulic pressure, closes the pressure reducing valve and retreats so as to reduce the pressure on the output side of the pressure reducing valve. Control valve device.