JPH021704B2 - - 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. There is a known pressure reducing valve that can proportionally reduce and transmit the pressure, and a pressure regulating spring that biases the pressure reducing valve in the opening direction to determine the pressure at which the pressure starts to be reduced. 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 large diameter cylinder hole 5a at the front, and a pressure receiving piston 6 is fitted into the cylinder hole 5b at the middle.
A stopper 1a that defines the retraction limit of the piston 6 is provided to protrude from the inner circumferential wall of the cylinder hole 5b. Rear cylinder hole 5
A depressurizing piston 21 is slidably connected to c through a sealing member 22. The depressurizing piston 21 is normally held at its forward limit, where it comes into contact with the front end wall of the cylinder hole 5c, by the elastic force of a set spring 23, which will be described later.

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. In the cylinder hole 5b, the pressure receiving piston 6 and the bearing 8 have the first
A front input hydraulic chamber 10 communicating with the inlet 2 ₁ is defined, and a rear output hydraulic chamber 11 communicating with the first outlet 3 ₁ is defined between the control piston 22 and the control piston 22 .

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 pressure reducing piston 2.
1 to open the valve 15.

A front spring chamber 19 that accommodates a pressure regulating spring 18 is defined at the front of the valve case 1 by a cover 1b. In the chamber 19, a lever 20 is installed at the front end of the _two piston rods 6a, 6a of the first and second pressure reducing valves ₄₁ , ₄₂ .
Both ends of the lever 20 are connected so as to be swingable, and this lever 20
The resilient force of the pressure regulating spring 18 is applied to the center of the piston 18 so as to press the pressure receiving pistons 6, 6 to the retracting limit.

Further, at the rear of the valve case 1, a rear spring chamber 32 for accommodating a set spring 23 is defined by a cover 1c. In the chamber 32, first and second pressure reducing valves 4 ₁ ,
A bridge plate 33 is separably or integrally connected to the rear ends of the pressure reducing pistons 21 and 21 of 4 _{and 2} , and the resilient force of the spring 23 set in the center of the bridge plate 33 pushes both the pressure reducing pistons 21 and 21 to the forward limit. It is applied so as to hold it under pressure. In this case, the elastic force of the set spring 23 is set to be larger than the retraction force of the pressure reducing pistons 21, 21 due to the maximum hydraulic pressure of the left and right output hydraulic chambers 11, 11.

Further, the valve case 1 has left and right cylinder holes 5b, 5.
A cylinder hole 34 parallel to these and closed at the front end is provided in the middle part of b, and the bridge plate 3 is inserted into this cylinder hole 34.
A control piston 35 that abuts on the central part of the piston 3 is slid together. The control piston 35 defines a control hydraulic chamber 36 between the control piston 35 and the front end wall of the cylinder bore 34 .

This control hydraulic chamber 36 is connected to the oil tank 25 and the pressure accumulator 26 via the solenoid valve 24.
When 4 is demagnetized, it communicates with the oil 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 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.

The working oil pressure of the left 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 left front wheel brakes Bf 1 and Br ₂ always rises together with the output oil pressure of the first and second output ports P ₁ and P _2.
The working oil pressure of the first and second output ports P ₁ , P ₂
After the output oil pressure of the first and second
The 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 this pressure regulating spring 1
1/2 of the set load of 8 becomes the valve opening force for one pressure receiving piston 6. ), 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.
Communication between 0 and 11 is cut off. Thereafter, the output hydraulic pressure of the first output port _P1 further increases, and the hydraulic pressure of the input hydraulic chamber 10 exerts a rearward pressing force 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). Input hydraulic chamber 1 to the difference between
The force obtained by multiplying the hydraulic pressure of 0 by the hydraulic pressure of the output hydraulic chamber 11 is applied to 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). As a result, 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, and the pressure receiving piston 6 is moved forward again to cut off the 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, if 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 first pressure reducing valve ₄₁ , and the output oil pressure of the second output port _P2 increases. It is clear that the pressure is reduced and transmitted to the left rear wheel brake Br ₁ in the comparative example.

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. The difference between the cross-sectional area of 6a and the piston rod 6
It is determined by the ratio of a to the cross-sectional area.

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 energized 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, in response to the oil pressure, the control piston 35 operates rearward and releases the set spring 2 through the bridge plate 33.
3 is compressed, and the pressing force of this set spring 23 against both pressure reducing pistons 21, 21 is released. For this reason, each pressure reducing piston 21 is moved backward by the hydraulic pressure of the corresponding output hydraulic chamber 11, but the pressure receiving piston 6 stops at the position where it contacts the stopper 1a, that is, at the backward limit, so that the valve opening rod 17 eventually becomes depressurized. Released from the pressing force of the piston 21 and allowing the valve 15 to close,
After the valve is closed, the pressure in the output hydraulic chamber 11 is reduced in accordance with the retreat of the pressure reducing piston 21. Thus the rear brake
The braking forces of Br ₁ and Br ₂ are weakened and a locked state is avoided. During this time, the pressure receiving piston 6 is held in the contact position with the stopper 1a by the hydraulic pressure of the input hydraulic pressure chamber 10, so the operating force of the control piston 35 is not transmitted to the pressure receiving piston 6, that is, no kickback phenomenon occurs.

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 36 is released to the oil tank 25. Therefore, the control piston 3
5 stops operating, both pressure reducing pistons 21,
21 is again held at the initial forward limit by the elastic force of the set spring 23, the pressure reducing valves 4 ₁ and 4 ₂ are returned to their normal operating states, and the braking force of the rear wheel brakes Br ₁ and Br ₂ is restored. .

In the above embodiment, both the left and right pressure reducing pistons 21,
21 are connected via a bridge plate 33, and one set spring 23 and one control piston 35 are provided in common for both pressure reducing pistons 21 and 21, respectively.
The set spring 23 and the control piston 35 may be provided for each pressure reducing piston 21 without using the bridge plate 33, and in this case, the pressure reducing piston and the control piston can be formed integrally.

As described above, according to the present invention, a valve case housing a pressure reducing valve and a pressure regulating spring is provided with a valve case that is held at the forward limit where the pressure reducing valve can be opened by the elastic force of the set spring during normal times. A pressure reducing piston that closes the pressure reducing valve when power is released and retreats to reduce the pressure on the output side of the pressure reducing valve, and a control that supplies hydraulic pressure from a hydraulic source when the rear wheels are about to enter a lock state. The control piston is provided with a hydraulic chamber and a control piston that is operated by the hydraulic pressure of the control hydraulic chamber to release the elastic force of the set spring from the pressure reducing piston.
When the rear wheels are about to lock up, the control piston is activated to move the pressure reducing piston backwards to reduce the rear wheel brake hydraulic pressure and avoid the locked condition.Moreover, during this anti-lock control, the pressure reduction Since the valve is held at the retraction limit by the output hydraulic pressure of the master cylinder and is not subjected to the actuation force of the control piston, no kickback phenomenon occurs.

In addition, in the unlikely event that a failure occurs in the hydraulic system of the control piston system and the control piston becomes inoperable, the pressure reducing piston can continue to maintain its normal forward position due to the elastic force of the set spring. , the pressure reducing valve performs its normal proportional pressure reducing function and does not interfere with braking, ensuring failsafe.

Furthermore, the anti-lock function can be provided by simply adding a pressure reducing piston, a set spring, and a control piston to a conventional brake hydraulic control valve device, so the configuration is simple, and by adding these, this type of control valve The original advantages of the device are not diminished in any way.

[Brief explanation of drawings]

The drawing is a brake hydraulic circuit diagram for an automobile equipped with a control valve device based on an embodiment of the present invention. Bf ₁ , Bf ₂ ...Left, right front wheel brake, Br ₁ , Br ₂
... Left and right rear wheel brakes, M ... Master cylinder, V ... Brake hydraulic control valve device, 1 ... Valve box, 1a ... Stopper, 6 ... Pressure receiving piston, 1
0...Input hydraulic chamber, 11...Output hydraulic chamber, 15...
... Valve, 18 ... Pressure regulating spring, 21 ... Pressure reducing piston, 23 ... Set spring, 24 ... Solenoid valve, 2
6... Pressure accumulator as a hydraulic source, 28... Hydraulic pump, 29... Control circuit, 35... Control piston,
36...Control hydraulic chamber.

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 opened, and a pressure regulating spring that biases the pressure reducing valve in the opening direction and determines the pressure reduction starting pressure. The pressure reducing valve is held at the forward limit where it can be opened by the elastic force of the spring, and when the elastic force of the set spring is released, the pressure reducing valve is opened and the pressure on the output side of the pressure reducing valve is reduced. a retracting decompression piston;
A control hydraulic chamber is supplied with hydraulic pressure from a hydraulic source when the rear wheel is about to enter a lock state, and a control piston is actuated by the hydraulic pressure of the control hydraulic chamber to release the elastic force of the set spring from the pressure reducing piston. A brake hydraulic control valve device for a vehicle, characterized in that: