JPH0435381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control device for an anti-skid device, and more particularly to a hydraulic pressure control device for an anti-skid device that can prevent brake pedal jerking.

In the past, various anti-skid devices have been proposed that increase or decrease brake fluid pressure to an optimal state in response to commands from a control unit in order to perform more effective and safe braking on any road surface when braking a vehicle. ing. However, in the conventional anti-skid device, as shown in FIG. When the brake fluid is switched to the depressurizing position, the brake fluid is discharged from the wheel cylinders 1 and 2 into a reservoir 6 and further returned to the pressure fluid supply line of the master cylinder 3 by a hydraulic pump 7. It is customary.

Therefore, in this type of hydraulic pressure control device for an anti-skid device, when the hydraulic pressure control valve 4 is in the pressure reducing position, the brake fluid returned to the pressure supply pipe by the hydraulic pump 7 is transferred to the master cylinder 3. The brake pedal 8 is pushed back against the driver's depression force through the piston of
There was a problem in that it gave the driver an unpleasant pedal feeling.

In order to solve these problems, as shown in FIG.
It has been proposed that the hydraulic pressure control valve 4 is provided with a pressure control valve 4 in the pressure reducing position to cut off the flow to the master cylinder 3. This is a hydraulic pressure control device for an anti-skid device disclosed in Japanese Patent Application Laid-open No. 142733/1983. However, in such a device,
Even when the brake is released, residual pressure is generated in the wheel cylinders 1 and 2 due to the cracking pressure of the check valve 10, causing problems such as dragging of the brake pads or brake shoes, resulting in significant wear of the brake pads and shoes. Therefore, it has been proposed to provide a relatively small diameter bypass path 11 as shown by the dotted line in FIG. However, although the flow rate is restricted by the bypass passage 11, the pressure fluid discharged from the hydraulic pump 7 is returned directly to the master cylinder 3 side, so the shock back cannot be completely eliminated, and it is said that the flow rate is prevented. The problem was that the original purpose was not fully achieved.

The present invention has been made against this background, and an object of the present invention is to provide a hydraulic pressure control device for an anti-skid device that can prevent pedal kickback.

The gist of the present invention, which has been made to achieve such an object, is that the control unit, which is provided between the master cylinder and the wheel cylinder, controls the wheel cylinder in response to a command from a control unit that determines the skid state of the wheel. a reservoir for storing brake fluid discharged from the wheel cylinder via the hydraulic pressure control valve when the brake fluid pressure decreases under the control of the hydraulic pressure control valve; Pressurizes the brake fluid stored in the
A hydraulic pressure control device for an anti-skid device, comprising: a hydraulic pump that returns fluid to a pressure fluid supply pipe connecting the master cylinder and the hydraulic pressure control valve; A hydraulic pressure responsive member is provided at a connection portion with a recirculation pipe that recirculates the discharged brake fluid and responds to the hydraulic pressure in the recirculation pipe, and by movement of the hydraulic pressure responsive member within the flow path, When the liquid pressure in the reflux pipe is above a predetermined value, connect the pressure liquid supply pipe on the side of the hydraulic pressure control valve to the reflux pipe, and when the liquid pressure in the reflux pipe is lower than a predetermined value. , a directional switching valve that connects the pressure fluid supply pipe on the hydraulic pressure control valve side to the pressure fluid supply pipe on the master cylinder side, and an accumulator connected to the recirculation pipe. The gist of this article is a hydraulic pressure control device for anti-skid equipment.

Embodiments of the present invention will be described in detail below based on the drawings.

In FIG. 3, reference numeral 14 denotes a master cylinder, which is connected to a brake pedal 16, and a first hydraulic pressure generating chamber therein is communicated via piping 18 to left and right wheel cylinders 20, 22 of the front wheels. The two hydraulic pressure generating chambers are communicated via piping 24 with left and right wheel cylinders of the rear wheels. That is, the piping 18 is branched into a pressure liquid supply line 26 and a pressure liquid return line 28 , and the pressure liquid supply line 26 is connected to the inlet port of the directional control valve 30 .
The pressure fluid supply pipe 32 connected to the outlet port of is connected to the wheel cylinder 20 of the front left wheel W1 via a hydraulic pressure control valve 34 and a pipe 36.

On the other hand, the pressure liquid return pipe 28 is connected to the left front wheel W1 via a check valve 38 whose forward direction is from the wheel cylinder 20 to the master cylinder 14, and a pipe 36.
It is connected to the wheel cylinder 20 of. The pipe line 40 connected to the hydraulic pressure control valve 34 includes a pipe line 42,
It is connected to the inlet port of the directional control valve 30 via a reservoir 44, a conduit 45, a check valve 46, a hydraulic pump 48, a check valve 50, and a return conduit 52. Further, an accumulator 54 is connected to the reflux pipe 52, and a pipe 5 branched from the reflux pipe 52.
6 is connected to a hydraulic pressure inlet of the directional control valve 30. Note that the check valves 46 and 50 define the direction from the reservoir 44 toward the directional switching valve 30 as a forward direction.

As shown in FIG. 4, the directional control valve 30 has two inlet ports 58, 60, one outlet port 62, and a hydraulic pressure introduction port 64, and each port has the pipe lines 26, 52, 32,56 are connected. A ball 66, which is part of a hydraulic response member, is disposed in a flow path that communicates the inlet ports 58, 60 and the outlet port 62 in the valve body.
When it moves to the left in the figure and is pressed against the seat surface, the flow path to the inlet port 60 is blocked, and the inlet port 58
When the ball 66 moves to the right and is pressed against the opposite sheet surface, the flow path to the inlet 58 is blocked, and the inlet port 60 and the outlet port 62 are communicated with each other. has been done. The ball 66 is biased by a compression coil spring 68 as a spring member in a direction such that the inlet 58 and the outlet 62 are always in communication. Further, a piston 70 is disposed in the valve body 69 at a position facing the compression coil spring 68 with a ball 66 interposed therebetween, and the compression coil spring 68 is The flow path can be switched to the opposite side against the urging force of. 72 is a small hole for air venting. By appropriately selecting the pressure receiving area of the piston 70, there is an advantage that the switching can be performed accurately and in a short time. In addition, in this embodiment, the ball 66 and piston 70 described above are
It constitutes a hydraulic response member.

In addition, instead of the directional switching valve 30, as shown in FIG.
inlet ports 58, 74 and one outlet port 6
It is also possible to use a directional valve 76 with . Instead of the ball 66, it is also possible to use a direction switching member, for example a rod-shaped member whose ends are shaped to fit the valve seat.
Note that the pressing force of the compression coil spring 68 needs to be considerably smaller than that of the directional control valve 30.

FIG. 6 shows the directional switching characteristics of the directional switching valves 30, 76. That is, in the case of the directional control valve 30, as shown in FIG.
Pa, pressure receiving area of piston 70 is A ₁ , return pipe 5
2 is blocked, the pressure receiving area of the ball 66 is
Assuming that A ₂ is the cross-sectional area of the piston rod, A ₃ is the cross-sectional area of the piston rod, F ₁ is the pressing force of the compression coil spring 68, and the tip of the piston rod is in point contact with the ball 66, the following equation holds true when switching the valve.

Pa (A ₁ + A ₂ - _{A 3} ) = A ₂ Pm + F ₁ ∴Pa = A ₂ / (A ₁ + A ₂ - A ₃ ) Pm + F ₁ / (A ₁ +
A ₂ −A ₃ )...(1) In the case of the directional control valve 76, if the pressing force of the compression coil spring 68 is F ₂ in FIG. 8, the following equation holds true in the same manner.

PaA ₂ =PmA ₂ +F ₂ ∴Pa=Pm+F ₂ /A ₂ F ₁ >>F ₂ , so if F ₂ ≒0, then Pa≒Pm...(2) In Figure 6, the shaded side is It shows a region where communication between the conduit 26 and the conduit 32 is cut off. 6th
In the figure, by changing A ₁ , A ₂ , A ₃ , F ₁ of the switching valve 30, the switching characteristics of the valve can be changed.
6, the switching characteristic becomes Pa=Pm, and when the valve is switched, the pressure in the pipe line 26 and the pipe line 52 are almost equal, so the pressure on the accumulator side (pipe line 52) will not be transmitted to the pipe line 26 side. It has the advantage of preventing shock when switching the valve, and also has the advantage of preventing shock when switching _the valve _.
If the value of _A3 is increased, the switching pressure will increase and Pa
It is also possible to store a sufficient amount of liquid in the accumulator 54 without switching until the pressure of Pm becomes sufficiently higher than the pressure of Pm.

The pressure reduction control valve 34 is a spring offset type 3-port 3-position solenoid valve, and when the excitation current of the solenoid 78 is at a high level, it is located at the solenoid 78 side, when it is at a low level, it is at the intermediate position, and when it is at 0 level, it is at the spring 80 side. It is configured to be able to be switched to the desired position.

In the wheel cylinder 22 of the right front wheel W2, a pressure fluid supply pipe 82 branched from the pressure fluid supply pipe 32 in the same manner as in the left front wheel W1 is connected to the hydraulic pressure control valve 34.
The master cylinder 14 and the wheel are connected via a hydraulic pressure control valve 84 and a pipeline 86 having the same configuration, and are also connected to the master cylinder 14 via a pressure fluid return pipeline 87 branched from the pipeline 18, a check valve 88, and a pipeline 86. The cylinder 22 is connected. A conduit 90 connected to the hydraulic pressure control valve 84 is connected to the reservoir 44 via the conduit 42 .

Further, the pipe 24 is connected to the wheel cylinders of the left and right rear wheels W3, W4 in the same manner as described above.
However, this is different from the above case in that two wheel cylinders are connected to one hydraulic control valve 92. Note that, similarly to the above, it is also possible to connect the wheel cylinders of the left and right rear wheels W3, W4 to the two hydraulic pressure control valves, respectively.

Vehicle speed sensors D are installed on the front wheels W1 and W2, respectively.
1 and D2 are provided, and 1 is provided as rear wheels W3 and W4.
A pulse signal having a frequency proportional to the rotational speed of each wheel obtained by the vehicle speed sensor D3 is applied as an input to the control unit 94. The control unit 94 calculates wheel speed, slip rate, deceleration, etc. based on this input, and generates control signals S1, S2, and S3. This control signal is transmitted to the hydraulic pressure control valve 34,
When the control signal is at a high level, the excitation current for the solenoid is at a high level, when the control signal is at a medium level, the excitation current is at a medium level, and when the control signal is at a low level, the excitation current for the solenoid is at a medium level. The current is set to zero level. That is, the control signals S1, S2, S
3 is at each of high, medium, and low levels, the hydraulic pressure control valves 34, 84, and 92 are respectively switched to the solenoid side position, intermediate position, and spring side position. The control signal has a high level when reducing the brake fluid pressure in the wheel cylinders 20 and 22, a medium level when maintaining the brake fluid pressure, and a low level when increasing the brake fluid pressure. In the case of rear wheels W3 and W4, the hydraulic pressure control valve 9 is operated in the same manner as described above.
2 is controlled.

The operation of the embodiment of the present invention configured as described above will be explained.

When the vehicle is in a constant speed state, when the driver begins to depress the brake pedal 16, the control unit 94 controls each wheel to reach a predetermined deceleration and slip rate based on the detection signal of the vehicle speed sensor at the time when braking is started. The control signals S1, S2, and S3 are each at a low level. Therefore, the hydraulic pressure control valves 34, 84, 92
are located on the spring side. Further, the directional switching valve 30 is connected to a pressure fluid supply pipe 26 on the master cylinder 14 side and a pressure fluid supply pipe 32 on the hydraulic pressure control valve 34 side.
are in a state of communication. Therefore, the brake fluid from the master cylinder 14 passes through the pressure fluid supply pipe 18, the directional control valve 30, the pressure fluid supply pipes 32, 82, the hydraulic control valves 34, 84, and the pipes 36, 86 to the left and right front wheels. Brakes will be applied to W1 and W2. Note that the brake fluid from the master cylinder 14 is transferred to the pipe line 36,
Flow towards 86 is blocked.

Similarly, for left and right rear wheels W3 and W4,
The brakes are applied.

When the brake fluid pressure increases and the front wheels W1 and W2 reach and exceed a predetermined deceleration or slip rate, their respective control signals go to a high level, and the hydraulic pressure control valves 34 and 84 operate as solenoids. placed in side positions, conduits 32 and 36, conduit 82 and conduit 8
6 is cut off, and the pipe line 36 and the pipe line 40, and the pipe line 86 and the pipe line 90 are communicated with each other. By this,
Brake fluid in wheel cylinders 20, 22 flows into reservoir 44 through lines 86, 90, 36, 40, 42. The hydraulic pump 48 is configured to start when either of the control signals S1, S2 reaches a high level, sucks the brake fluid in the reservoir 44, then pressurizes the brake fluid, and connects the check valve 50 and the return pipe. 52 to the accumulator 54 and the directional control valve 30. When the brake fluid is sent into the pipe line 56, the piston 70 and the ball 66, which are hydraulic pressure responsive members, are pressed, and the return pipe line 52 and the pressure fluid supply line 32 on the side of the hydraulic pressure control valve 34 communicate with each other.
Communication with the pressure fluid supply pipe 26 on the master cylinder 14 side is completely cut off, and the pressure energy of the brake fluid is stored in the accumulator 54. The left and right rear wheels W3 and W4 are similarly configured. Therefore, no jerking occurs on the brake pedal 16.

When the deceleration of the wheels W1, W2 recovers to a predetermined deceleration and is about to become smaller, the control signal becomes a medium level, and the hydraulic pressure control valves 34, 84
is placed in the neutral position, and the pipe line 32 and the pipe lines 36 and 40 are cut off, and the pipe line 82 and the pipe lines 86 and 90 are cut off, respectively. Therefore, the brake fluid pressure remains constant. At this time, the hydraulic pump 48 is discharging the brake fluid in the reservoir 44 to the pipes 52 and 56, but the brake pedal 14 does not jerk as described above. The above applies to the rear wheel W.
The same applies to 3 and W4.

Next, when the skid state of the wheels W1 and W2 is released, both the control signals S1 and S2 become low level again, the pipe line 32 and the pipe lines 36 and 86 are communicated with each other, and the pressure of the accumulator 54 is reduced through the pipe line 32. is transmitted to the pipe 36 and the pipe 86, and the front vehicles W1, W2
The braking force increases. Similarly, when the control signal S3 becomes low level again, the braking force applied to the rear wheels W3 and W4 increases.

Thereafter, similar control is repeated, and when the vehicle reaches a desired speed or comes to a stop, the driver releases the brake pedal. As a result, the check valve 3 provided in the pressure liquid return pipes 28, 87
8 and 88, and the brake fluid in the wheel cylinders 20 and 22 flows through conduits 36, 28, 18 and conduits 86, 87, 18, respectively.
is returned into the master cylinder 14 through the. The same applies to the rear wheel hydraulic pressure circuit.

Although one embodiment of the present invention has been described above, vehicle speed sensors may be provided on the left and right rear wheels to generate control signals respectively. It is also possible to control the left and right front wheels with one hydraulic pressure control valve. Furthermore, it is also possible to control the brake fluid pressure to the wheel cylinders in two ways depending on the skid state of the wheels: pressure increase and pressure decrease.

Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and can be implemented in various forms without departing from the gist of the present invention. Of course.

As described in detail above, according to the hydraulic pressure control device for an anti-skid device of the present invention, a directional control valve is provided at the connection portion between the hydraulic pressure supply pipe and the return pipe that recirculates the brake fluid discharged from the hydraulic pump. is provided, and when the brake fluid pressure in the recirculation pipe becomes high, that is, when the fluid pressure control valve is in a reduced pressure state,
By moving within the flow path of a hydraulic response member that responds to the hydraulic pressure in the reflux pipe, communication between the pressure fluid supply pipe to the master cylinder and the above-mentioned reflux pipe is cut off, and
Since an accumulator is provided in the recirculation conduit so that hydraulic pressure can be accumulated, there is an effect that no jerking is exerted on the brake pedal even in the reduced pressure state.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing a first conventional example of a hydraulic pressure control device for an anti-skid device, and FIG. 2 is a hydraulic circuit diagram showing a second conventional example. Fig. 3 is a hydraulic circuit diagram showing one embodiment of the present invention;
The figure is a schematic sectional view of a directional control valve applied to the same embodiment, FIG. 5 is a schematic sectional view of another directional control valve, and FIG. 7 is an explanatory diagram of the directional switching valve shown in FIG. 4, and FIG. 8 is an explanatory diagram of the directional switching valve shown in FIG. 5. 14... Master cylinder, 20, 22... Wheel cylinder, 26, 32, 82... Pressure liquid supply pipe line, 34, 84, 92... Liquid pressure control valve, 30, 7
6... Directional switching valve, 38, 88... Check valve, 44
... Reservoir, 48 ... Hydraulic pump, 52 ... Return pipe, 54 ... Accumulator, 66 ... Ball, 68 ... Compression coil spring, 70 ... Piston, 94 ... Control unit.

Claims (1)

[Scope of Claims] 1. A hydraulic pressure control valve that is provided between a master cylinder and a wheel cylinder and that controls the brake fluid pressure of the wheel cylinder in response to a command from a control unit that determines the skid state of the wheel; a reservoir for storing brake fluid discharged from the wheel cylinder via the fluid pressure control valve when brake fluid pressure decreases under control of the fluid pressure control valve; pressurizing the brake fluid stored in the reservoir;
A hydraulic pressure control device for an anti-skid device, comprising: a hydraulic pump that returns fluid to a pressure fluid supply pipe connecting the master cylinder and the hydraulic pressure control valve; A hydraulic pressure responsive member is provided at a connection portion with a recirculation pipe that recirculates the discharged brake fluid and responds to the hydraulic pressure in the recirculation pipe, and by movement of the hydraulic pressure responsive member within the flow path, When the liquid pressure in the reflux pipe is above a predetermined value, connect the pressure liquid supply pipe on the side of the hydraulic pressure control valve to the reflux pipe, and when the liquid pressure in the reflux pipe is lower than a predetermined value. , a directional switching valve that connects the pressure fluid supply pipe on the hydraulic pressure control valve side to the pressure fluid supply pipe on the master cylinder side, and an accumulator connected to the recirculation pipe. Hydraulic pressure control device for anti-skid equipment. 2 The directional switching valve communicates between an inlet from the reflux pipe, an inlet from the master cylinder side pressure fluid supply pipe, and an outlet to the hydraulic fluid supply pipe on the hydraulic pressure control valve side. The hydraulic response member is movably provided on a flow path where the hydraulic response member is moved, and normally, the hydraulic response member is pressed in a certain direction by a spring member, and the inlet from the pressure fluid supply pipe on the master cylinder side is moved. forming a flow path that communicates between the inlet from the reflux pipe and the outlet, moving the hydraulic responsive member by pressure fluid supplied from the inlet from the reflux pipe, and connecting the inlet from the reflux pipe to the outlet; The hydraulic pressure control device for an anti-skid device according to claim 1, wherein the hydraulic pressure control device can be switched to a communicating flow path. 3. The directional switching valve has a hydraulic responsive member sandwiched therebetween, a piston is disposed at a position opposite to the spring member, and the piston is pressed by pressure fluid introduced from a pipe line communicating with the return pipe line. A hydraulic pressure control device for an anti-skid device according to claim 2, which enables flow path switching.