JPH0338453A - Anti-skid controller - Google Patents

Abstract

PURPOSE:To secure fail-safe function at the time of pump failure to rapidly perform initial pressure reduction at the time of control start by providing a hydraulic pump, changeover valves, a reservoir chamber and a pressure reducing valve comprising a check valve. CONSTITUTION:It is possible to quickly perform initial pressure reduction of anti-skid control by making hydraulic pressure of wheel cylinders 4 to 7 escape to a reservoir chamber 24 of a pressure reducing valve 18 via electromagnetic valves 14 to 17. Since pump hydraulic pressure drops at the time of failure of a pump 12, changeover valves 8.9 are changed over to the side of a master cylinder 3 and a check valve comprising a ball-like valve body 23 and springs 25, 26 of the pressure reducing valve 18 is opened to make close circuits between the wheel cylinders 4 to 7 and between the pressure reducing valve 18 and the wheel cylinders 4 to 7 so that shortage in braking force can be avoided thereby attaining fail-safe function.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anti-skid control device that prevents wheels from locking.

[Conventional technology]

Conventionally, as an anti-skid control device, Japanese Patent Application Laid-Open No. 57-10
As shown in Japanese Patent No. 447, a simple system for anti-skid and traction control is proposed in which wheel cylinder pressure is directly adjusted by controlling oil pressure of a pump.

[Problem to be solved by the invention]

However, in the above conventional system, a return valve that is opened by the pump's control hydraulic pressure is installed between the wheel cylinder and the reservoir as a measure against pump failure, so the initial pressure reduction at the start of anti-skid control is due to the pump characteristics. There is a problem of delays due to influence.

The present invention has been made in view of the above points, and an object of the present invention is to provide an anti-skid control device that has a reliable fail-safe function in the event of a pump failure and can quickly perform initial pressure reduction at the start of control. .

[Means to solve the problem]

For this purpose, the present invention includes: a solenoid valve that controls the hydraulic pressure of a wheel cylinder; a hydraulic pump that generates the hydraulic pressure; and a hydraulic pump that is actuated by the control hydraulic pressure of the hydraulic pump and supplies the hydraulic pressure to the master cylinder or the hydraulic pressure of the master cylinder. Hydraulic pump control '4111? It consists of a switching valve that switches to the Itl pressure, a reservoir chamber to which the hydraulic pressure in the wheel cylinder is guided via the solenoid valve, and a check valve that is opened by the control hydraulic pressure of the hydraulic pump and controls the hydraulic pressure that is released from the reservoir chamber. Adopt the technical means of providing a pressure reducing valve.

[Effect]

According to the present invention, the initial pressure reduction for anti-skid control can be quickly performed by releasing the hydraulic pressure of the wheel cylinder to the reservoir chamber of the pressure reducing valve via the electromagnetic valve.

In addition, when the pump fails, the pump oil pressure decreases, so the switching valve switches to the master cylinder side, and the check valve of the pressure reducing valve closes to create a closed circuit between the master cylinder wheel cylinder and between the pressure reducing valve and the wheel cylinder, and brake A fail-safe function is achieved by avoiding a situation where power is insufficient.

〔Example] Hereinafter, a first embodiment of the present invention will be described based on the drawings.

In FIG. 1 showing a brake device having an anti-skid control function, a brake pedal 1 is connected to a master cylinder 3 via a vacuum booster 2, and the hydraulic pressure generated in the master cylinder 3 when the brake pedal 1 is depressed is as follows. Wheel cylinders 4 and 5 provided at each wheel through a conduit
, 6.7, and a braking action is performed.

The master cylinder 3 is of a tandem type and has two pressure chambers (not shown) that output brake hydraulic pressure of the same pressure, and each pressure chamber is connected to a supply pipe 40, 50, respectively.

The supply pipe 40 is connected to a communication pipe 41 via a switching valve 8, and further branches into communication pipes 42, 43.

The communication pipe 42 is connected to the wheel cylinder 4 via the solenoid valve 14.
The brake pipe 44 is connected to the brake pipe 44, which communicates with the brake pipe 44. Similarly, the communication pipe 43 is connected to a brake pipe 45 communicating with the wheel cylinder 5 via the solenoid valve 15. check valve 3
5 is installed in a branch pipe 46 installed in parallel with the switching valve 8,
Brake fluid is allowed to flow only from the communication pipe 41 to the supply pipe 40.

The supply pipe 50 also has the same connection relationship as the supply pipe 40, and is connected to the communication pipe 51 via the switching valve 9, and further connected to the communication pipe 52.
．． It branches to 53. The communication pipe 52 is connected to a brake pipe 54 that communicates with the wheel cylinder 6 via the solenoid valve 16.

Similarly, the communication pipe 53 is connected to a brake pipe 55 communicating with the wheel cylinder 7 via the solenoid valve 17. The check valve 36 is installed in a branch pipe 56 installed in parallel with the switching valve 9 and allows the brake fluid to flow only from the communication pipe 51 to the supply pipe 50.

Wheel cylinders 4, 5, 6; 7 are for the front right wheel FR, the rear left wheel RL, the front left wheel FL, and the rear right wheel RR, respectively, and the brake pipes 45° and 55 of each rear wheel are equipped with a known P valve. 64.65 will be installed.

Since the switching valves 8 and 9 have the same configuration, the explanation regarding the switching valve 8 will be explained below.
To clarify, this is the supply pipe 40 directly connected to the master cylinder.
A port connected to the A port, a B boat connected to the communication pipe 41 that communicates with the wheel cylinder via the solenoid valve 14.15, and a C boat connected to the branch pipe 60 to which the discharge oil of the pump 12 is guided. It has three ports, and a branch pipe 61 branched from the branch pipe 60 is connected to a pilot pressure introduction port.

The switching valve 8 is a hydraulically operated two-position valve, and the first
At this position, the supply pipe 40 and the communication pipe 41 are communicated with each other, and the branch pipe 60 is cut off. On the other hand, in the second position, the branch pipe 60
The communication pipe 41 is communicated with the supply pipe 40, and the supply pipe 40 is cut off.

A check valve 37 is installed in the branch pipe 60 between the branch point between the branch pipe 60 and the branch pipe 61 and the switching valve so as to only allow oil to flow from the pump 12 to the switching valve 8.

The discharge oil pressure of the pump 12 is supplied to a branch pipe 7 branched from a branch pipe 46.
A relief valve 10 whose pilot input is the hydraulic pressure introduced by the branch pipe 56, and a relief valve 1 whose pilot input is the hydraulic pressure introduced by the branch pipe 72 branched from the branch pipe 56.
1 through a branch pipe 60.

Next, the pressure reducing valve 18 will be explained. The pressure reducing valve 18 includes a pressure reducing piston 22, a ball-shaped valve body 23, and a spring 2.
Check valve consisting of 5.26 and reservoir piston 20
, a compression coil spring 21, a reservoir mechanism consisting of a reservoir chamber 24, and a housing 19 containing them.

The pressure reducing piston 22 has a stepped shape, and has a small diameter O-ring 27 and a large diameter O-ring 28 on the sliding portion, respectively, and a protrusion for opening the valve body 23 on the small diameter side. and,
The piston 22 is biased by a compression coil spring 25 in a direction in which the valve body 23 and the projection are separated. Furthermore, the piston 22 operates in response to the hydraulic pressure introduced into the chamber 29 via the branch pipe 72 and the hydraulic pressure introduced via the branch pipe 66.

The valve body 23 is normally seated on a conical valve seat by the action of a spring 26 and blocks communication between the reservoir chamber 24 and the pipe 63.

The reservoir piston 20 has an O-ring on its sliding portion, and is slidably provided within the housing 19. and,
The piston 20 is connected to the reservoir chamber 24 together with the housing 19.
is formed. Further, the piston 20 is connected to the spring 2
1 and compresses the brake fluid in the reservoir chamber 24. The reservoir chamber 24 includes branch pipes 47, 48, and 57.5 introduced into the normally closed ports of the solenoid valves 14 to 17.
It communicates with the branch pipe 62 where the pipes 8 and 8 have merged.

Further, the chamber formed by the end face of the small diameter portion of the piston 22 and the housing 19 is connected to the relief valve 10.11 and the pump 12.
It communicates with the reservoir 4 which is directly connected to the master cylinder 3 through a branch pipe 63 as well as the suction port of the reservoir 4 .

Therefore, when the valve body 23 is seated on the valve seat, the normally closed ports F of the solenoid valves 14 to 17 are cut off from the reservoir 4 of the master cylinder 3, and when the valve body 23 is open, the reservoir 4 and the solenoid valve 14 are closed. ~17 normally closed boats F are connected to the so-called "
"Open loop."

Each wheel has an electromagnetic pickup type wheel speed sensor 31,
32, 33, and 34 are installed, and the signals are manually input to the anti-skid control electronic control unit (ECU) 30. The objects controlled by the ECU 30 are an electric motor 13 that is a drive source for the pump 12 and electromagnetic valves 14 to 17 that control the oil pressure of each wheel cylinder 4 to 7. Solenoid valve 14-1
7 is a solenoid valve with 3 points and 2 positions, and in the first position shown in the figure, communication pipes 42, 43, 52, 53 and brake pipe 44 are connected.
．． 45, 54.55, and in the second position, the brake pipes 44.45, 54.55 communicate with branch pipes 47° 4B, 57.58 which communicate with the reservoir 4 via the pressure reducing valve 18.

Next, the operation of the configuration shown in FIG. 1 will be explained.

(1) During normal braking During normal braking, the motor 13 is in a non-energized state. Therefore, no pressure is generated in the branches 60, 61, so that the switching valve 8.9 is in the first position as shown. Furthermore, the electromagnetic valves 14 to 17 are also in the non-energized state, so they are in the first position shown. Therefore, when the brake pedal 1 is depressed, the hydraulic pressure generated in the master cylinder 3 is guided to each wheel cylinder 4 to 7 through the switching valves 8 and 9 and the electromagnetic valves 14 to 17 to generate braking force.

(2) During anti-skid control During braking, as a result of calculation by the ECU 30 based on the wheel speed signals from the wheel speed sensors 31, 32, 33° 34, one of the wheels tends to lock, and anti-skid control should be started. In this state, the pump 12 is continuously driven by a signal from the ECU 30 and discharges the brake fluid sucked from the reservoir 4. This oil pressure is regulated to be slightly higher than the oil pressure generated by the master cylinder 3 by the relief valves 10 and 11, and the switching valves 8 and 9 are set to the second position via the branch pipe 61, and the supply pipe 40, 50 and the communication pipe 41° are connected to each other. 51 is cut off. That is, the flow of brake fluid from the master cylinder 3 to the wheel cylinders 4 to 7 is blocked.

At the same time, the spring 25 is connected to the pressure reducing piston 22 of the pressure reducing valve 18 from the branch pipe 60 that supplies the control hydraulic pressure of the pump 12.
A force that exceeds the force due to the master cylinder hydraulic pressure introduced into the chamber 29 is applied to move the pressure reducing piston 22 to the left in the figure, and the protruding portion of the pressure reducing piston 22 opens the valve body 23. As long as the pump 12 is driven, the valve body 23 is opened, and the branch pipe 4 connected to the pressure reducing boat of the solenoid valves 14 to 17 is opened.
7 4B, 57.58 and reservoir 4 communicate.

In this state, when the solenoid valves 14 to 17 are controlled by the ECU 30, when the solenoid valves 14 to 17 are in the first position shown in the figure, the wheel cylinders 4 to 7 are controlled by the control oil pressure of the pump 12 sucked up from the reservoir 4. pressure, solenoid valves 14-17
When in the second position, a brake fluid flow is formed in which the hydraulic pressure of the wheel cylinders 4 to 7 is released to the reservoir 4.

In this way, during anti-skid control, the hydraulic pressure of the master cylinder 3 is restricted by the switching valve 8.9.
So-called kick pack, in which hydraulic pulsations generated by the operation of the pump 12 and the electromagnetic valves 14 to 17 reach the brake pedal l via the master cylinder 3, is prevented.

Moreover, the control hydraulic pressure of the pump 12 is controlled by the relief valve 10.11.
The pressure is regulated to be slightly higher than that of the master cylinder 3, so even though it is disconnected from the mask cylinder 3, the braking force is commensurate with the driver's pedal force.
There is virtually no shortage or excess of brakes.

EC indicates that the conditions for ending anti-skid control have been met.
If determined at U30, the ECU 30 stops the pump 12 and ends the control of the electromagnetic valves 14 to 17. pump 12
With the stoppage of the switching valves 8 and 9, the switching valves 8 and 9 go to the first position, and the pressure reducing valve 1 day's pressure reducing screw l-22 returns to its initial state by the return force of the spring 25 and the force of the master cylinder oil pressure, and the valve body 23 returns to its initial state. Closed by the force of the spring 26. The pressure oil required to operate the switching valves 8 and 9 and the pressure reducing valve 18 in the pump discharge oil flows back from the pump discharge port to the suction port when the pump 12 stops, so it can be quickly returned. becomes.

On the other hand, on the downstream side of the switching valves 8 and 9, the pressure oil of pressures 4 to 7 is prevented from flowing back toward the pump by the check valves 37 and 38, and the braking force after control can be ensured.

Next, when the brake pedal 1 is released during anti-skid control, the pump 12 continues to be driven, but the relief valve 10
．． Since the pressure regulated at 11 is slightly higher than the control hydraulic pressure of the master cylinder 3, return the pedal 1 completely and
When the control oil pressure of the master cylinder 3 becomes almost zero, both the switching valve 8.9 and the pressure reducing valve 18 return to their initial states by their respective spring forces. The brake fluid at this time returns to the reservoir 4 through the relief valve 10.11.

Next, the operation of the pressure reducing valve I8 will be described in detail. Pressure reducing valve 18
The function of is to ensure braking force in the event that the control hydraulic pressure of the pump 12 is abnormally low or does not occur. That is,
If the anti-skid control conditions are satisfied even when the control oil pressure of the pump 12 is abnormal, the ECU 30 drives the solenoid valves 14 to 17. In this case, abnormally low pressure means a pressure so low that the switching valves 8 and 9 do not operate, and anti-skid control is performed even if the switching valves 8 and 9 do not operate. Therefore, the switching valves 8 and 9 are switched to the mask cylinder 3 side, and the brake fluid necessary for control is supplied from the master cylinder 3 instead of from the pump 12. At this time, if the valve body 23 of the pressure reducing valve 18 is open, that is, in communication with the reservoir 4, if the anti-skid control continues for a long time, the amount of oil in the master cylinder 3 may become insufficient, resulting in insufficient braking force. There is.

However, in the present invention, since the pressure reducing piston 22 does not operate, the valve body 23 closes and anti-skid control is performed normally until the reservoir chamber 24 is filled. Thereafter, when the reservoir piston 20 is displaced to the left in the figure to the maximum position, the oil pressure in the wheel cylinders 4 to 7 cannot be reduced, and the normal braking state is established, making it possible to secure the braking force.

Furthermore, to explain the operation of the pressure reducing valve 18 when the control hydraulic pressure of the pump 12 is abnormal, the switching valves 8 and 9 and the pressure reducing valve 18 are both operated by the control hydraulic pressure of the pump 12, but the pressure required for operation is controlled by the switching valve 8. The pressure reducing valve 18 is set higher than the pressure reducing valve 9. Specifically, the switching valves 8 and 9 operate because the force due to the pressure from the branch pipe 16 overcomes the opposing spring force, so the pressure corresponding to the spring force becomes the operating pressure. on the other hand,
The pressure reducing valve 18 uses the master cylinder hydraulic pressure introduced from the spring 25 and the branch pipe 72 as a force opposing the control hydraulic pressure of the pump 12 which is the operating pressure. Since the master cylinder oil pressure acts on the stepped portion of the pressure reducing piston 22, the force that pushes the pressure reducing piston 22 to the left becomes the pressure applied to the small diameter O-ring 27 of the pressure reducing piston 22.

If the control hydraulic pressure of the pump 12 is normal and approximately equal to the master cylinder pressure, the switching valves 8 and 9 operate with the balance between the force applied to the small diameter O-ring 27 and the force of the spring 25.
However, if the control oil pressure of the pump 12 is abnormally low, the force that returns the pressure reducing piston 22 to the right will be strong depending on the difference between the master cylinder oil pressure and the control oil pressure of the pump 12, and the valve body 23 is in the closed state. Even when the control hydraulic pressure of the pump 12 is abnormal, the switching valves 8 and 9 will operate if a pressure exceeding the spring force is generated, but the pressure reducing valve 18 will not operate even if the force exceeds the force of the spring 25 because the master cylinder hydraulic pressure is applied. In reality, it will not operate unless a pressure close to the master cylinder oil pressure is generated. As described above, there is a situation in which the switching valve 8.9 operates and the pressure reducing valve 18 does not operate when the control oil pressure of the pump 12 is abnormal, but the reverse is not true. Braking force from the cylinder 3 is ensured.

Next, another feature of the pressure reducing valve 18 will be explained.

Normally, in an open loop system, the downstream side of the boat on the pressure reduction side of the solenoid valves 14 to 17 that control the pressure in the wheel cylinders is communicated with the reservoir 4 of the master cylinder 3. However, when the valve body 23 is opened and closed to ensure braking force when the pump pressure is abnormal, the pressure reduction characteristic, which is the most important phenomenon in anti-skid control, deteriorates.

This is because it is necessary to start the pump 12, operate the pressure reducing piston 22, and open the valve body 23 from the time when anti-skid control is started until the oil pressure is actually reduced from the wheel cylinders 4 to 7. This is because it creates a time lag. The time required for a wheel that has a tendency to lock to lock is very short, and the above time lag has many uncertain factors such as the characteristics of the pump 12 and the movement of the depressurizing piston 22, so although it may become longer, it cannot be shortened. Have difficulty.

In the present invention, at the start of control, the pressure reduction delay caused by the reservoir chamber 24 at the start of the rear skid control is only the activation delay of the electromagnetic valves 14 to 17, and favorable initial pressure reduction characteristics are obtained.

In other words, when anti-skid control is started, the solenoid valve 14
-17 becomes the second position, and the oil pressure of each wheel cylinder 4-7 is transferred to the branch pipes 44, 45, 57.
．． The oil is guided from 58 to 62 to the reservoir chamber 24, and the reservoir piston 20 compresses the spring 21 and moves to the left to expand the reservoir 24, and the wheel cylinder oil pressure is quickly reduced. After that, the pressure of the pump 12 operates the pressure reducing piston 22, and the check valve 23 opens.
The brake fluid in the reservoir chamber 24 is returned to the reservoir 4 via the pipe 63. Subsequently, the reservoir piston 20 is returned to its original position by the spring 21 and no longer functions as a reservoir.

In this way, the reservoir chamber 24 acts only when the pressure is reduced at the initial stage of anti-skid, and contributes to rapid pressure reduction.

Next, a second embodiment of the present invention will be described with reference to FIG.

Figure 2 shows the case where the system is applied to a rear-wheel drive vehicle where each brake piping system is separated into front and rear wheels, and slip control for the drive wheels (rear wheels) is added to anti-skid control. Show the system. In this second embodiment, except for the change in piping, three two-bottom two-position valves 81, 82 and 83 are added to the configuration shown in FIG. The solenoid valve 81 is located on the reservoir side of the relief valve 10.11, and is located at the first position in the figure.
In the position, the relief valve 10.11 communicates with the reservoir 4, and in the second position, the communication is cut off. However, in the second position, a relief valve 84 is built in that allows only the flow of brake fluid from the relief valve 10.11 side to the reservoir 4 side. The solenoid valve 82 is located in a branch pipe 56 branching from the brake supply pipe 50 that supplies hydraulic pressure to the rear wheels, and is connected to the check valve 3.
6 and in the first position shown, the branch pipe 56
The communication is interrupted in the second position.

The solenoid valve 83 is located between the branch point 85 of the pump discharge pipe 60 to the switching valve 8.9 and the switching valve 8 that connects and shuts off the brake fluid supply pipe 40 to the front wheels, and is located at the first position in the figure. In the second position, the pump 13 and the switching valve 8 are communicated with each other, and in the second position, the communication is cut off. All solenoid valves 81, 82, 83 are ECU3O
Switching between the first position and the second position is performed by an electrical signal from.

The operation of traction control, which is wheel slip control during acceleration, will be explained. Simultaneously with the start of control, the solenoid valves 81, 82, 83 are set to the second position and driven by the pump 12 and motor 13.

The solenoid valve 81 eliminates the function of the relief valve 10.11 and regulates the control hydraulic pressure of the pump 12 to the pressure set by the relief valve 84 built in the solenoid valve 81. Further, the solenoid valve 82 is in the closed position to prevent the control hydraulic pressure of the pump 12 from flowing out to the master cylinder 3. Furthermore, the solenoid valve 83 prevents the control hydraulic pressure of the pump 12 from flowing out to the front wheels.

As described above, when the driving wheels slip traction, the three electromagnetic valves 81, 82, 83 and the pump can be operated to supply a predetermined pressure to the rear wheels, which are the driving wheels. Hydraulic control of the wheel cylinders 6.7 at this time is performed by electromagnetic valves 14 to 17 in the same way as anti-skid control, and the wheels are controlled to optimally skid.

As described above, the traction function can be added using three 2-point and 2-position valves, and the total cost including anti-skid can be reduced.

Next, a third embodiment of the present invention shown in FIG. 3 will be described.

In FIG. 3, which shows only the pressure reducing valve 180, the pressure reducing piston 220 has a sliding surface at one place and the O ring 27 is omitted, and the O ring 27 is omitted.
Only ring 28 is attached.

The pressure reducing piston 220 is urged rightward by the spring 25 and closes the valve body 23. The operation is the same as in the first embodiment, in which the pressure reducing piston 220 is moved to the left by the control pressure of the pump 12, the valve body 23 is opened, and the reservoir 4 and the pressure reducing boat of the solenoid valve are communicated. The spring force and pressure receiving area of each valve are adjusted so that the operating pressure of the pressure reducing valve 180 is higher than that of the switching valves 8 and 9 when the control oil pressure of the pump is abnormal.

In short, if the pressure reducing valve 180 is operated at a higher pressure than the switching valve 9.10, even if the pump pressure is abnormally low, the switching valve 8.9 will not operate and the pressure reducing valve 180 will operate, and the anti-skid control will be performed. There is no risk that the amount of oil from the master cylinder will be insufficient due to the continuous operation, and that the braking force will decrease.

It should be noted that the present invention is not limited to the embodiments described above, and, for example, if
The magnetic valve may be a 3-point, 3-position valve instead of a 3-point, 2-position valve.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reliably perform a fail-safe function in the event of a pump failure, and to quickly perform initial pressure reduction at the start of control, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a schematic block diagram showing a first embodiment of the present invention, Fig. 2 is a schematic block diagram showing a second embodiment of the present invention, and Fig. 3 shows main parts of a third embodiment of the present invention. FIG. 3... Master cylinder, 4-7... Wheel cylinder, 8.9... Switching valve, 14-17... Solenoid valve,
18...Reducing valve, 22...Piston, 24...Reservoir chamber. 180...pressure reducing valve.

Claims (1)

[Scope of Claims] A solenoid valve that controls hydraulic pressure of a wheel cylinder; a hydraulic pump that generates the hydraulic pressure; and a hydraulic pump that is operated by the control hydraulic pressure of the hydraulic pump and supplies the hydraulic pressure to the solenoid valve according to the hydraulic pressure of a master cylinder or the hydraulic pump that generates the hydraulic pressure. a switching valve that switches to the control hydraulic pressure of the hydraulic pump; a reservoir chamber to which the hydraulic pressure in the wheel cylinder is guided via the solenoid valve; and a check that controls the hydraulic pressure that is opened by the control hydraulic pressure of the hydraulic pump and released from the reservoir chamber. An anti-skid control device comprising a pressure reducing valve consisting of a valve.