JPH021702B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a braking system in which the brake hydraulic circuit of a vehicle is configured into two mutually independent systems using a dual master cylinder having independent first and second output ports. In particular, the present invention relates to a brake hydraulic control valve device that supplies hydraulic pressure reduced by the hydraulic pressure of the front brakes as the hydraulic pressure of the rear brakes.

As this type of brake hydraulic control valve device, each independent first valve connects the first and second output ports of the master cylinder and the left and right rear wheel brakes.
A common valve box is interposed in the second oil passage, and the output hydraulic pressure of the first and second output ports can be proportionally reduced and transmitted to the left and right rear wheel brakes, respectively. first and second pressure reducing valves arranged in parallel;
It is known that a lever is provided between the two pressure reducing valves, and a pressure regulating spring that biases the two pressure reducing valves in the opening direction via the lever and determines their pressure reduction start pressure. There is. 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 rear brakes can be operated weakly to achieve efficient braking.
Moreover, there are advantages such as a compact structure can be obtained by making the valve case and the pressure regulating spring common to the first and second pressure reducing valves.

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.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a simple and effective brake hydraulic control valve device that can exhibit an anti-lock function without sacrificing the advantages described above.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, in FIG. 1, M is a known tandem master cylinder operated by a brake pedal Bp, and has independent first and second output ports.
It has 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 first output port P1 extends from the first output port _P1 .
The hydraulic operating parts of the left front wheel brake Bf ₁ and the right rear wheel brake Br ₂ are connected to the oil passage L ₁ , and the right front wheel brake is connected to the second oil passage L ₂ extending from the second output port P ₂ .
The hydraulic operating parts of Br ₂ and left rear wheel brake Br ₁ are connected. Therefore, the first and second oil passages L ₁ ,
L ₂ is the so-called X-shaped piping. Then, the first and second oil passages L ₁ leading to the left and right rear wheel brakes Br ₁ and Br ₂ ,
The brake hydraulic pressure control valve device V of the present invention is installed in _L2 .

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 third 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.

A cylinder hole 5 whose rear end is closed is formed in the valve case 1, into which a pressure receiving piston 6 is slidably fitted via a seal member 7. This pressure receiving piston 6 is
a piston rod 6a protruding from its front end surface;
The piston rod 6a has a valve seat member 6b protruding from the rear end surface, and the intermediate portion of the piston rod 6a is slidably supported by a bearing 8 fitted in the valve case 1 via a seal member 9. The pressure receiving piston 6 divides the inside of the cylinder hole 5 into a front input hydraulic chamber 10 communicating with the first inlet ₂₁ and a rear output hydraulic chamber 11 communicating with the first outlet ₃₁ . do.

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 where the valve seat member 6b corresponds to the closed end wall of the cylinder hole 5, the valve opens. A rod 17 is adapted to be pushed against the closed end wall to open the valve 15.

A spring chamber 19 for accommodating a pressure regulating spring 18 is defined in the front part of the valve case 1 by a cover 1a. 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.

Further, the valve case 1 is provided with a third cylinder hole 21 which is parallel to the two cylinder holes 5, 5 and whose rear end is closed, in the middle part of the two cylinder holes 5, 5.
A control piston 22 that abuts on the central portion of the piston is slidably engaged with the piston. Thus, the control piston 22 is connected to the cylinder hole 21.
A control hydraulic chamber 23 is defined between the rear end wall and the rear end wall.

This control hydraulic chamber 23 is connected to an oil tank 25 and a pressure accumulator 26 via a solenoid valve 24.
When 4 is demagnetized, it communicates with the hydraulic tank 25, and when it is energized, it communicates with the pressure accumulator 26. The pressure accumulator 26 stores oil discharged from a hydraulic pump 28 driven by an electric motor 27.

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 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.

The working oil pressure of the front wheel brakes Bf ₁ and Bf ₂ always rises together 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 always increases with the output oil pressure of the first and second output ports P 1 and P 2} . After the output oil pressures of the first and second output ports P ₁ and P ₂ exceed a predetermined value, the first and second pressure reducing valves 4 ₁ and 4 ₂ are 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, the valve hole 14 is closed, and the input/output hydraulic chambers 10, 11 are closed. cut off communication between Thereafter, the output hydraulic pressure of the first output port _P1 further increases, and the hydraulic pressure of the input hydraulic pressure chamber 10 exerts a rearward pressing force on the pressure receiving piston 6 (the cross-sectional area of the large diameter portion and the cross-sectional area of the sealing member 6a are applied to the pressure receiving piston 6). The difference between the area and the input hydraulic chamber 10
The force obtained by multiplying the hydraulic pressure of the output hydraulic pressure chamber 11 by the hydraulic pressure of the output hydraulic chamber 11 overcomes the forward pressing force of the hydraulic pressure of the output hydraulic chamber 11 against the pressure receiving piston 6 (the force obtained by multiplying the cross-sectional area of the large diameter portion of the pressure receiving piston 6 by the hydraulic pressure of the output hydraulic chamber 11). 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, so that the pressure in the output hydraulic chamber 11 is increased. The forward pressing force of the hydraulic pressure on the pressure receiving piston 6 increases immediately, moving the pressure receiving piston 6 forward again and cutting off communication between the two hydraulic chambers 10 and 11. Thereafter, the same action is repeated as the output oil pressure of the first output port _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 . Ru.

Furthermore, when the output oil pressure of the second output port _P2 rises above a predetermined value, the second pressure reducing valve ₄₂ operates in the same manner as the pressure reducing valve ₄₁ , and the output oil chamber 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 pressure accumulator 26 and the control hydraulic chamber 23 communicate with each other. , pressure accumulator 2
6 of oil pressure is supplied to the control oil pressure chamber 23. Then, the control piston 22 moves forward in response to the oil pressure, and moves the pressure receiving pistons 6, 6 of the pressure reducing valves 4 ₁ , 4 ₂ forward through the lever 20 against the force of the pressure regulating spring 18 . Since each valve 15, 15 is closed and the output hydraulic chambers 11, 11 are depressurized by the forward movement of the pressure receiving pistons 6, 6, the braking force of the rear wheel brakes Br ₁ , Br ₂ is weakened, resulting in a locked state. is avoided.

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 control hydraulic chamber 23 is released to the hydraulic tank 25. Therefore, since the control piston 22 stops operating, each pressure reducing valve 4 ₁ , 4 ₂ is returned to its normal operating state, and the rear wheel brakes Br ₁ , 4 2 are restored to their normal operating states.
Restores Br ₂ 's braking power.

FIG. 2 shows a second embodiment of the invention. That is 2
The pressure receiving piston 6, the piston rod 6a of the 6,
6a and the lever 20 are brought into contact with each other so as to be swingable and separable, and the other configurations are the same as those of the previous embodiment. In this embodiment, the control piston 22
When activated, only the lever 20 is pulled away from each piston rod 6a, 6a to release the pressing force of the pressure regulating spring 18 against each pressure receiving piston 6. The combination of the hydraulic pressures 10 and 11 moves forward and reduces the pressure in the output hydraulic chamber 11.

As described above, according to the present invention, the control hydraulic chamber is provided with hydraulic pressure from the hydraulic source when the rear wheel is about to enter the lock state, in the valve case housing the first and second pressure reducing valves, the lever, and the pressure regulating spring. and a control piston that can be actuated by the hydraulic pressure of the control hydraulic chamber to push the lever against the elastic force of the pressure regulating spring, so that when the rear wheels are about to become locked, By the operation of the control piston, each pressure reducing valve is operated to reduce the hydraulic pressure of the rear wheel brake, thereby making it possible to avoid the above-mentioned locking phenomenon. Furthermore, the anti-lock function can be provided by simply adding one control piston to the conventional brake hydraulic control valve device, so the structure is extremely simple. Also,
The provision of this control piston does not impair the inherent advantages of this type of brake hydraulic control valve arrangement.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional plan view showing a first embodiment of the present invention, and FIG. 2 is a longitudinal partial plan view showing the second embodiment. 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, 19... Spring chamber, 20...
... Lever, 22 ... Control piston, 23 ... Control hydraulic chamber, 24 ... Solenoid valve, 25 ... Oil tank, 2
6... Pressure accumulator as a hydraulic source, 28... Hydraulic pump, 29... Control circuit, 30 ₁ , 30 ₂ ... First,
Second wheel speed sensor.

Claims (1)

[Claims] 1. A common valve box is installed in each of the independent first and second oil passages connecting the first and second output ports of the master cylinder and the left and right rear wheel brakes, and this valve box is , first and second pressure reducing valves arranged in parallel capable of proportionally reducing and transmitting the output hydraulic pressure of the first and second output ports to the left and right rear wheel brakes, respectively, and a bridge between the two pressure reducing valves. In the brake hydraulic control valve device, the brake oil pressure control valve device is provided with a pressure regulating spring that biases both the pressure reducing valves in the opening direction via the lever and determines their pressure reduction start pressures. A control hydraulic chamber is supplied with hydraulic pressure from a hydraulic source when the rear wheels are about to enter a lock state, and the lever is actuated by the hydraulic pressure of this hydraulic chamber to push the lever against the elastic force of the pressure regulating spring. A brake hydraulic control valve device for a vehicle, characterized in that a control piston is provided.