JPH0643182B2 - Anti-skidding control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anti-skid control device for suitably eliminating wheel lock generation during vehicle braking.

[Conventional technology]

Recently, various types of anti-skid control technologies have been proposed to improve safety during vehicle braking.
As a typical example of such a thing, for example, a brake hydraulic pressure transmission path (hereinafter referred to as a main path) that connects between a master cylinder (hydraulic pressure generation device) and a braking device is always open and the brake hydraulic pressure needs to be lowered. A normally open solenoid valve-type hold valve that is sometimes closed is arranged, and a bypass-connected path (hereinafter referred to as bypass path) is provided for this main path, and the brake device side of this bypass path and the main path. The output pressure system is divided by a pressure reducing valve that is normally closed, and the brake pressure oil that flows into the bypass passage is received, for example, by receiving a pressure through the pressure reducing valve of the normally closed solenoid valve that opens when the brake hydraulic pressure needs to drop. To reduce the hydraulic pressure by increasing the volume of the room to store in the reservoir mechanism,
Further, a pressure oil return mechanism including a pump for stored oil in the reservoir mechanism is used to pump up to the main path, and the opening / closing switching operation of the hold valve (normally open type) and pressure reducing valve (normally closed type) is performed during vehicle braking. There has been proposed an electronic control circuit for detecting the wheel lock of the above.

By the way, in the anti-skid control as represented by the above-mentioned example, the main path for transmitting the brake oil pressure is divided into the paths of the input system and the output system by the normally open type hold valve, and the anti-skid control at the time of anti-lock braking is performed. Since the pressure oil in the brake device (that is, the pressure oil in the output path) is pumped up to the master cylinder side (that is, the input path side), the hydraulic pressure fluctuation in the master cylinder becomes large. There is a problem in that the brake pedal interlocking with the cylinder is given a movement called so-called kickback.

For this reason, a device for avoiding the kickback phenomenon has been conventionally made. For example, as shown in JP-A-55-19700, pressure oil is provided only upstream in the input path for pumping the brake oil pressure and only in the downstream direction. It has also been proposed to arrange a check valve that allows the flow of.

However, in such a system, as a matter of course, there is a separate path for returning the hydraulic pressure at the time of brake release from the brake device (hereinafter, W / C) side to the master cylinder (hereinafter, M / C) side. In addition to this, this hydraulic pressure return path reliably blocks the flow of pressure oil in the opposite direction of M / C → W / C, and is provided in the brake device W / C to prevent dragging when releasing the brake. Since it is indispensable to leave no residual pressure, it becomes difficult to design the entire system or process accuracy.

Therefore, the applicant of the present invention, as an alternative to the above-described check valve, shuts off the main path to the input system and the output system only during anti-skid control, and enables brake hydraulic pressure reduction or pressurization in the output system. We provide a gate valve. This gate valve uses a hydraulic pressure drop in the output system during anti-skid control to switch the normally open valve to the closed circuit due to the hydraulic pressure difference between the output system and the input system.

By the way, an anti-skid control device using such a gate valve is suitable in terms of preventing kickback at the time of control, but depressurizing, pressurizing, and holding the brake hydraulic pressure for releasing the wheel lock. Is dependent on the operation of the hold valve and pressure reducing valve, which are solenoid valves. Especially, for the re-pressurization of the brake oil pressure, which was devised to prevent wheel relocking, the pulsed opening and closing of the hold valve is finely controlled. Therefore, it is necessary to select rapid pressurization or slow pressurization.

However, in order to increase the versatility of the anti-skid control device, it is necessary to provide a device that is as inexpensive as possible and that can satisfy most of the purposes of anti-skid control of the vehicle in terms of control characteristics. is there.

Further, it is also required to make the pressurization of the brake hydraulic pressure as smooth as possible during the anti-skid control to prevent an undesirable tendency such as relocking in the behavior of the wheel due to vibration or the like.

[Problems to be Solved by the Invention]

The present invention has been made in view of the above various viewpoints, and an object thereof is to prevent occurrence of kickback, to prevent re-locking of wheels, and to control a solenoid valve or its control system. An object of the present invention is to provide a device that can be provided easily and inexpensively.

Another object of the present invention is to continuously and smoothly pressurize the brake hydraulic pressure during anti-skid control,
Accordingly, it is an object of the present invention to provide a device capable of smoothly performing wheel speed recovery behavior by suppressing oscillatory changes in brake hydraulic pressure.

[Means for Solving the Problems]

Thus, the feature of the anti-skid control device according to the present invention made to realize such an object is that a normally open type gate valve is provided in order from the upstream side to the brake hydraulic pressure transmission path from the master cylinder to the braking device. A normally-closed solenoid valve, which is a normally open solenoid valve that is closed by inputting a hydraulic pressure holding command signal during anti-skid control, is opened and a normally closed type that is opened by receiving a hydraulic pressure reduction command signal during anti-skid control. An anti-return bypass passage for pressure oil circulation that pumps up the pressure oil on the side of the brake device to a pressure accumulator via a solenoid valve and returns the pressure oil from the pressure accumulator between the gate valve and the hold valve of the transmission path. In the skid control device, the gate valve receives a hydraulic pressure on the brake device side at one end surface and a hydraulic pressure from the pressure accumulator at the other end surface. When the hydraulic pressure from the pressure accumulator exceeds the hydraulic pressure on the downstream side of the hold valve by a predetermined pressure or more, the gate piston closes the transmission path regardless of the master cylinder side hydraulic pressure. Is a structure in which the hold valve is provided with a communication path by an orifice that is bypassed.

It is preferable that the orifice in the above configuration is provided as sufficiently smaller than the flow path when the hold valve is opened.

〔Example〕

 The present invention will be described below based on embodiments shown in the drawings.

In the figure, 1a to 1c are paths (main paths) for transmitting brake hydraulic pressure, which are connected so as to communicate between a master cylinder M / C (not shown) and a wheel cylinder W / C of a brake device, and a gate on the way. It passes through the on-off valve chamber 2a of the valve 2, passes through the hold valve 3, and reaches the wheel cylinder W / C. The hold valve 3 is a normally open type valve that is electromagnetically closed, and the closed circuit is a brake hydraulic pressure holding (and decompression) signal that is output by an unillustrated anti-skid control circuit so as to cancel the wheel lock during vehicle braking. It is designed to be activated by. The gate valve 2 always opens the on-off valve chamber 2a as described later, and the main path 1a,
It connects between 1b.

Reference numeral 4 denotes a bypass passage that is bypass-connected to the main passage 1c downstream of the hold valve 3, and is a normally closed type pressure reducing valve 5, which is electromagnetically opened by an antiskid pressure reducing signal 5, a reservoir 6, a pump 7, a pressure accumulator. The accumulator 8 and the return valve 9 with a built-in pressurizing piston, which will be described later, are sequentially provided, and when the pressure reducing valve 5 is opened, the brake hydraulic pressure (the hydraulic pressure in the main passage 1c and the wheel cylinder W / C) is applied to the reservoir 6. The pressure is reduced by inflowing the oil, and this pressure oil is pumped up to the accumulator 8 by the pump 7 and then the return valve 9
To the main path 1b between the gate valve and the hold valve.

Next, the structure of the gate valve 2 will be described. The gate valve 2 of this example is a stepped cylinder 1 in a cylinder body (not shown).
The gate piston 12 is housed in 0 and 11 and its small diameter end faces the chamber 16 communicating with the main passage 1c downstream of the hold valve 3 and has a large diameter due to the return spring 13 engaged with the large diameter flange 12a. It is designed to be stationary while being biased to a predetermined position on the end side. The gate piston 12 is located in the on-off valve chamber 2a and cooperates with the valve seat 14 to close the on-off valve chamber 2a by the movement against the spring force of the return spring 13 of the gate piston 12. The valve body 15 is provided so as to cut off the communication between the main paths 1a and 1b when the valve is closed.

The movement of the return spring 13 of the gate piston 12 against the spring force is due to the difference in hydraulic action acting in both axial directions, that is, the hydraulic pressure F ₁ from the chamber 16 acting on the small diameter end and the large diameter end portion of the gate piston 12. the difference ΔF of _F 1 -F ₂ hydraulic force _{F 2} of the facing chamber 17 is effected by exceeding the spring force of the return spring 13, the chamber 17,
Therefore, the opening / closing valve chamber 2a of the gate piston 12 is closed, specifically, the opening of the hold valve 3 and the opening of the pressure reducing valve 5 are caused by the start of the anti-skid control, and the braking device is opened. This is caused by the oil pressure inside being reduced and the pressure oil being pumped up to the accumulator.

The relief valve 1 built in the gate piston 12
Nos. 8 and 19 are main paths 1b and 1b, respectively, when the brake is released.
It is for returning the pressure oil of 1c to the main path 1a.

Reference numeral 20 is an orifice provided in the middle of the path 21 that is connected to the hold valve 3 by bypass, and allows the pressure oil to flow gently when the hold valve 3 is closed.

According to such a configuration, the pressure reduction of the brake hydraulic pressure at the initial stage of the anti-skid control is given by the closing circuit of the hold valve 3 and the opening circuit of the pressure reducing valve 5, and the gate valve 2 is substantially closed by this movement. Kickback due to subsequent changes in brake hydraulic pressure will not occur at all. The re-pressurization of the brake hydraulic pressure after the wheel lock is released is given by the return of the pressure reducing valve 5 to the closed circuit and the return of the hold valve 3 from the open circuit. In the case of this example, this re-pressurization is shown in FIG. As shown, it will be given as a combination of characteristic slow and rapid pressurization. That is, when the hold valve 3 is first turned on (closed) by the start of the anti-skid control, the brake hydraulic pressure rises at a slow increase rate determined by the orifice 20 as shown in FIG. 2 (see t _{1 to} t ₂₎ . ).
Then further pressure reducing valve 5 by revealing the detection of the wheel locking tendency is turned on (opened), the brake hydraulic pressure is dive (see t ₂ ~t _3). When the wheel speed is sufficiently recovered by the decrease of the brake oil pressure, the pressure reducing valve 5 is turned off (closed) (see t _{3 to} t ₄ ), and therefore the brake oil pressure is the pressure oil from the accumulator 8 through the orifice 20. It will be gradually increased in pressure (at this time, the hold valve 3
Is still closed). Increased pressurization of brake hydraulic pressure
If too on whether slow as compared to recovery of about wheel speed state, the hold valve 3 off (open circuit) is performed, the brake hydraulic pressure shows a steep pressure rise (see t ₄ ~t _5). The rapid increase in the brake hydraulic pressure may be performed simultaneously with the closing of the pressure reducing valve 5, such as the hold valve, the pressure reducing valve,
Open / close control is an anti-skid control that determines whether the brake hydraulic pressure needs to be reduced or increased (slow pressurization or rapid pressurization) depending on the wheel speed state, and outputs a corresponding solenoid valve actuation signal The anti-skid control circuit may be a known circuit as it is, or may be appropriately designed by utilizing it.

Such a re-pressurizing characteristic of the brake hydraulic pressure quickly increases the brake hydraulic pressure that is generally low enough to release the wheel lock, thereby preventing the extension of the braking distance and increasing the hydraulic pressure to a certain level after Can effectively cope with the brake hydraulic pressure application method of anti-skid control, which is considered to be desirable to gently increase the brake hydraulic pressure in consideration of preventing wheel relocking, and the effectiveness of this example is great. It can also be understood from FIG.

In addition, since the pressurization of the brake hydraulic pressure, especially the gentle pressurization, is performed through the orifice, there is no vibrational transmission of the hydraulic pressure compared to the case where the electromagnetic valve is pulsed and opened and closed repeatedly, and the wheel behavior is smooth. Since it is changed to, there is an effect that more preferable anti-skid control can be realized.

〔The invention's effect〕

The anti-skid control device according to the present invention does not cause so-called kickback because fluctuations in the brake hydraulic pressure during anti-skid control are not transmitted to the brake pedal side, and also reduces the brake hydraulic pressure for eliminating wheel locking tendency and brake hydraulic pressure. It is possible to provide a relatively simple control system for the solenoid valve that pressurizes, and since the brake hydraulic pressure is continuously and gently applied, there is no vibrational change in the hydraulic pressure.
There is an effect that smooth wheel behavior can be obtained, and its usefulness is great.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of an anti-skid control device according to the present invention, and FIG. 2 is a diagram explaining control characteristics of brake hydraulic pressure. 1a-1c: Main path, 2: Gate valve 2a: Open / close valve chamber, 3: Hold valve 4: Bypass path, 5: Pressure reducing valve 6: Reservoir, 7: Pump 8: Accumulator, 9: Return valve 10, 11: Stage Cylinder with 12: Gate piston, 12a: Large diameter flange 13: Return spring 14: Valve seat, 15: Valve body 16,17: Chamber 18, 19: Relief valve 20: Orifice, 21: Path

Claims (1)

[Claims] 1. A normally open type gate valve is sequentially closed from the upstream side in a brake hydraulic pressure transmission path from a master cylinder to a brake device, and then a normally open type is closed with a signal of a hydraulic pressure holding command during anti-skid control as an input. Along with a hold valve that is a solenoid valve, through a normally closed solenoid valve that is opened by receiving a signal of a hydraulic pressure reduction command during anti-skid control, pumping pressure oil on the side of the brake device to a pressure accumulator, And in the anti-skid control device having a bypass passage for returning the pressure oil of the pressure accumulator between the gate valve and the hold valve of the transmission passage, the gate valve has a hydraulic pressure on the brake device side at one end face. And a gate piston that receives the oil pressure from the pressure accumulator on the other end surface, and the oil pressure from the pressure accumulator exceeds the oil pressure on the downstream side of the hold valve by a predetermined pressure or more. The anti-skid control device is characterized in that the gate piston closes the transmission path irrespective of the master cylinder side hydraulic pressure, and further the communication path is provided with a communication path by an orifice bypassing the hold valve. .