JPH0536774Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic circuit for a wheel slip control device that performs, for example, acceleration slip control (traction control) or anti-skid control.

[Prior Art] In recent years, in addition to preventing the drive wheels from spinning when the vehicle starts or accelerates, the rotation of the drive wheels is controlled to maximize the frictional force between the drive wheels and the road surface when the vehicle accelerates. 2. Description of the Related Art Acceleration slip control devices are used to improve running stability, acceleration, etc. of vehicles. On the other hand, a so-called anti-skid control device is used which controls the rotation of the wheels so as to obtain an optimum braking force without causing the wheels to lock up when braking the vehicle.

Furthermore, a wheel slip control device has been proposed which combines the above-mentioned acceleration slip control device and anti-skid control device so that running stability of the vehicle is maintained both when the vehicle accelerates and when the vehicle decelerates. ing. (For example, JP-A No. 61-10864, etc.) As shown in FIG. 3, the wheel slip control device A1 includes a switching circuit A2 for switching the hydraulic circuit depending on acceleration slip control or anti-skid control. It was set up. This switching circuit A2 includes a one-way valve A4 (check valve) and a solenoid valve A5 that can be switched to two positions between the flow paths between the master cylinder side and the wheel cylinder side.
(Solenoid valves) are arranged in parallel. The check valve A4 prevents pressure oil from flowing from the wheel cylinder side to the master cylinder side. Also, solenoid valve A5
is composed of a valve body A6, a spring A7, an excitation coil A8, and a flow passage port A9, and the pressure oil flow passage is opened and closed by moving the valve body A6 to open and close the flow passage port A9 provided on the master cylinder side. It is something to do.

Excitation coil A8 of this solenoid valve A5
is normally demagnetized, so the valve body A6 is
A spring A7 provided on the master cylinder side presses the channel port A7 toward the wheel cylinder side.
9 is in the open state. On the other hand, excitation coil A8
is excited, that is, during acceleration slip control, the valve body A6 is pressed toward the master cylinder side by the electromagnetic force that acts in the opposite direction to the spring force, and the flow passage port A
9 is in the closed state.

As a result, pressure oil is supplied from the hydraulic circuit for acceleration slip control (not shown) to the wheel cylinder side, regardless of the supply of pressure oil from the master cylinder side, and the braking of the wheels is controlled.

Even if the brake pedal is depressed during this acceleration slip control, pressure oil is supplied to the wheel cylinder side via the check valve A4, and the wheels are braked. After the braking, when the brake pedal is released and the solenoid valve A5 is opened, the hydraulic pressure on the wheel cylinder side decreases, and the braking of the wheels is released.

[Problems to be solved by the invention] However, the spring A7 may be damaged due to frequent opening and closing operations of the solenoid valve A5.
In addition, the valve body A6 sometimes became stuck and did not move. If such damage or sticking occurs, for example, when the brake pedal is depressed during acceleration slip control in which the excitation coil is energized, the
Even when the brake pedal was released and the excitation coil A8 was demagnetized, the valve body A6 did not return to the wheel cylinder side, and the flow path remained blocked. As a result, the oil pressure on the wheel cylinder side remains high, resulting in the problem that the brake remains applied.

[Means for solving the problem] The present invention, which was made to solve the above problem, includes a master cylinder that supplies pressure oil according to the depression force of the brake pedal, and a master cylinder that is connected to the master cylinder through a flow path. a wheel cylinder that brakes the wheels; a one-way valve that is disposed between the flow path between the master cylinder and the wheel cylinder and allows only pressure oil to flow from the master cylinder side to the wheel cylinder side; A solenoid valve is arranged in parallel with the valve and opens and closes a flow path between the master cylinder and the wheel cylinder. The spring is configured to open the flow path by pressing in the direction, and the flow path is normally opened, while when energized, an electromagnetic force is applied to the valve body to close the flow path against the pressing force of the spring. In the hydraulic circuit for a wheel slip control device, the spring is arranged to press the valve body in the direction of flow of pressure oil from the wheel cylinder side to the master cylinder side. This article focuses on hydraulic circuits for slip control devices.

[Operation] According to the configuration according to the present invention, the master cylinder supplies pressure oil according to the depression force of the brake pedal;
A one-way valve and a solenoid valve are provided in parallel between the flow path connecting the wheel cylinder that brakes the wheels. This one-way valve prevents pressure oil from flowing from the wheel cylinder side to the master cylinder side, and the solenoid valve normally has a valve body pressed toward the master cylinder side by a spring installed on the wheel cylinder side. This establishes a communication state and opens the flow path for pressure oil.

During acceleration slip control, the excitation coil of the electromagnetic valve is excited, and the electromagnetic force moves the valve body toward the wheel cylinder to block the flow path of pressure oil. Thereby, pressure oil is supplied from the hydraulic circuit for acceleration slip control to the wheel cylinder side, regardless of the supply of pressure oil from the master cylinder side, and the braking of the wheels is controlled.

When the flow path is blocked by the excitation of this excitation coil, when the brake pedal is depressed and pressure oil is supplied to the wheel cylinder side via the one-way valve, the oil pressure in the wheel cylinder side increases. The vehicle rises and the braking of the wheels is controlled. and,
After that, when the brake pedal is released and the excitation coil is demagnetized, the oil pressure on the wheel cylinder side is higher than the oil pressure on the master cylinder side, so even if the spring is damaged or the valve body is stuck,
By pressing and moving the valve body toward the master cylinder, that is, in the direction in which the pressure oil returns, the solenoid valve can be brought into communication and the flow path can be opened. As a result, the oil pressure on the wheel cylinder side decreases, so the state in which the brake is applied to the wheels does not continue.

[Example] An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a switching circuit 4 of the hydraulic circuit 2 for a wheel slip control device, and FIG. 2 shows the hydraulic circuit 2 for a wheel slip control device.

As shown in FIG. 2, the wheel slip control hydraulic circuit 2 includes an anti-skid control actuator 6 and an acceleration slip control actuator 8.
It is provided between the flow path between the master cylinder 10 and the wheel cylinder 14 that brakes the wheels 12.

The switching circuit 4 described in this embodiment is used to control the braking of the rear wheels 12c and 12d, so the hydraulic circuit used for braking the front wheels 12a and 12b of the anti-skid control actuator 6 is omitted. do.

The structure of the anti-skid control actuator 6 includes the anti-skid capacity control valve 1.
8 is connected to the master cylinder 10 via a proportional valve 20, and its anti-skid capacity control valve 18 is connected to the wheel cylinder 14 via a pipe P1 and an actuator 8 for controlling acceleration slip. A pump 26 for pumping pressure oil from the reservoir 22 through a check valve 24 is connected to an accumulator 28. The accumulator 28 is connected to the acceleration slip control actuator 8 via a pipe P2 in order to supply the pressure oil, and is further connected to the regulator 30. The regulator 30 is connected to the master cylinder 10 via a pipe P3.
They are each connected to the reservoir 22 via a pipe P4, and further connected to a hydraulic circuit (not shown) used for braking the front wheels 12a, 12b via a pipe P6. Furthermore, this regulator 30 is connected to the second solenoid valve 34, the first solenoid valve 32, and the anti-skid capacity control valve 18 via a pipe P8 branched from the pipe P6. The first solenoid valve 32 is a two-position valve that can be switched between a communication state and a flow rate restriction state, and the second solenoid valve 34
and the cylinder 18a. The second solenoid valve 34 is a two-position valve that switches the flow path between the regulator 30 and the first solenoid valve 32 or the reservoir 22, and is connected to the regulator 30, the reservoir 22, and the first solenoid valve 32.

Further, in the configuration of the acceleration slip control actuator 8, the switching circuit 4 is connected to the anti-skid capacity control valve 18 and the acceleration slip capacity control valve 36 (slave cylinder). This slave cylinder 36 is connected to a third solenoid valve 38 and a fourth solenoid valve 40, and the third solenoid valve is connected to the accumulator 28 and the fourth solenoid valve to receive pressure oil supply.
The solenoid valves 40 are each connected to a reservoir for releasing pressure oil. The accumulator 28, pump 26, reservoir 22, etc. are shared with the anti-skid control actuator 6.

The switching circuit 4, as shown in FIG.
A one-way valve (check valve) 42 and a fifth solenoid valve 44 are arranged in parallel. This fifth solenoid valve 44 has a valve body 46
control spring 48 and excitation coil 5 for driving
0, flow passage port 52 on the master cylinder 10 side and wheel cylinders 14c, 1 for rear wheels 12c, 12d
The flow path opening 54 is provided on the 4d side and opens and closes the flow path. Check valve 4 above
2 prevents pressure oil from flowing from the wheel cylinders 14c, 14d to the master cylinder 10. Further, the fifth solenoid valve 44 has a control spring 48 that is connected to the wheel cylinders 14c, 14d.
It is placed on the side, and is normally placed on the valve body 4.
6 is connected to the master cylinder 10 by the control spring 48.
The channel opening 54 is opened by being pressed to the side, and the master cylinder 10 and the wheel cylinders 14c and 14d are in communication. And excitation coil 5
0 is excited, the valve body 46 resists the spring force due to the electromagnetic force, and the wheel cylinder 14
c and 14d, the channel opening 54 is closed, and the channel is placed in a blocked state.

Next, the operation of the wheel slip control hydraulic circuit 2 during anti-skid control and acceleration slip control will be explained.

First, during anti-skid control, the fifth solenoid valve 44 does not receive excitation current from an electronic control circuit (not shown), so the control spring 48
(Fig. 1), the anti-skid capacity control valve 18 and the wheel cylinder 14 are opened.
c and 14d are set in a position where they are in communication with each other.

In this state, when increasing the braking force, the first
The solenoid valve 32 is brought into communication, and the second solenoid valve 34 is switched so that the first solenoid valve 32 and the regulator 30 are brought into communication. Thereby, the hydraulic pressure from the accumulator 28 is transmitted to the anti-skid capacity control valve 18 via the regulator 30, the pipe P6, the pipe P8, the second solenoid valve 34, and the first solenoid valve 32. The hydraulic pressure from the anti-skid capacity control valve 18 is transmitted to the wheel cylinders 14c and 14d via the pipe P1 and the switching circuit 4 in communication.

On the other hand, when reducing the braking force, the second solenoid valve 34 is connected to the cylinder 18a and the reservoir 2.
2 so that they communicate with each other. As a result, the pressure oil in the cylinder 18a of the anti-skid capacity control valve 18 is released to the reservoir 22, and the oil pressure applied to the wheel cylinders 14c and 14d is also reduced. In addition, during anti-skid control, from other anti-skid capacity control valves (not shown),
Pressure oil is supplied to the wheel cylinders 14a, 14b for the front wheels 12a, 12b.
The braking control of b is performed.

Next, during acceleration slip control, the fifth solenoid valve 44 receives an excitation current from an electronic control circuit (not shown), and the control spring 48 (FIG. 1)
The anti-skid capacity control valve 18 and the wheel cylinder 14 close against the pressing force of
c and 14d are kept in a position where they are cut off from each other. In this state, when increasing the braking force, the third solenoid valve 38 is opened, the fourth solenoid valve 40 is closed, and the pressure oil from the accumulator 28 is transferred to the slave via the pipe P2. The pressure oil in the spring chamber 36b side of the slave cylinder 36 is supplied to the control chamber 36a side of the cylinder 36, and the pressure oil in the spring chamber 36b side of the slave cylinder 36 is supplied to the wheel cylinders 14c, 1.
4d. On the other hand, when reducing the braking force, the fourth solenoid valve 40 is opened, the third solenoid valve 38 is closed, and the pressure oil on the control chamber 36a side of the slave cylinder 36 is released to the reservoir 22. .

Next, the operation of the switching circuit 4 and its fifth solenoid valve 44 will be explained. As mentioned above, during acceleration slip control, the fifth solenoid valve 44
is in a cutoff state, but since a check valve 42 is provided in parallel with it, at this time,
When the brake pedal 56 is depressed, the wheel cylinder 14 is moved from the master cylinder 10 side.
Hydraulic pressure is transmitted to the rear wheels 12c and 14d through the check valve 42 to brake the rear wheels 12c and 12d. Then, when the brake pedal 56 is subsequently released and the braking force of the rear wheels 12c, 12d is weakened, the supply of excitation current to the excitation coil 50 (FIG. 1) is stopped.

At this time, if the control spring 48 is damaged or the valve body 46 is stuck, it is difficult for the control spring 48 to move the valve body 46 to the communicating position. However, the control spring 48 of the fifth solenoid valve 44 is arranged on the wheel cylinder 14c, 14d side, as shown in FIG.
Since the hydraulic pressure has become high due to the depression of the brake pedal 56, the valve body 46 can be pressed toward the master cylinder 10, that is, in the direction in which the pressure oil returns (in the direction of arrow B). Therefore, by moving the valve body 46, the wheel cylinders 14c, 14d can be easily removed.
The flow passage port 54 provided on the side can be opened, thereby relaxing the braking force of the rear wheels 12c, 12d.

That is, during acceleration slip control, the brake pedal 5
6 is stepped on, the fifth solenoid valve 44
Even if the vehicle is out of order, if the brake pedal 56 is released, the braking force on the wheels 12 can be quickly released and the vehicle can be driven safely.

[Effects of the invention] As explained above, according to the invention, a one-way valve that prevents pressure oil from flowing from the wheel cylinder side to the master cylinder side is provided between the flow path between the master cylinder and the wheel cylinder. , and a solenoid valve that opens and closes the flow path is arranged in parallel with the solenoid valve, and a valve body is installed on the wheel cylinder side of the solenoid valve in the direction of flow of pressure oil from the wheel cylinder side to the master cylinder side. A spring is provided that presses to open the flow path. Therefore, when the oil pressure on the wheel cylinder side is high, even if the solenoid valve spring is damaged or the valve body is stuck, demagnetizing the excitation coil will clear the flow path in the return direction to the master cylinder side. It never becomes blocked. As a result, the hydraulic pressure on the wheel cylinder side can be easily reduced, so that the braking force on the wheels can be quickly released, and the fail-safe function of the vehicle can be improved.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the switching circuit of the present invention, Figure 2
This figure is a schematic diagram of a hydraulic circuit for a wheel slip control device, and FIG. 3 is an explanatory diagram showing a conventional switching circuit. 2...Hydraulic circuit for wheel slip control device, 4...
...Switching circuit, 10...Master cylinder, 14
... Wheel cylinder, 44 ... Fifth solenoid valve (electromagnetic valve), 42 ... Check valve (one-way valve), 46 ... Valve body, 48 ... Control spring, 5
0... Excitation coil.

Claims (1)

[Scope of Claim for Utility Model Registration] A master cylinder that supplies pressure oil according to the force applied to the brake pedal; A wheel cylinder that is connected to the master cylinder via a flow path and brakes the wheels; The master cylinder and the wheels. A one-way valve that is placed between the flow path with the cylinder and allows only pressure oil to flow from the master cylinder side to the wheel cylinder side; a solenoid valve that opens and closes a flow path; the solenoid valve includes a valve body that opens and closes a pressure oil flow path; a spring that presses the valve body in one direction to open the flow path; A hydraulic circuit for a wheel slip control device, comprising: an excitation coil configured to open the flow path, apply an electromagnetic force to the valve body during excitation, and close the flow path against the pressing force of the spring; A hydraulic circuit for a wheel slip control device, wherein the spring is arranged so as to press the valve body in the direction of flow of pressure oil from the wheel cylinder side to the master cylinder side.