JPH08133048A - Anti-lock braking device - Google Patents

Abstract

PURPOSE: To utilize rear wheel braking force more efficiently than an actual braking force distribution even when diagonal wheels are select-low controlled at the same time. CONSTITUTION: In anti-lock control pressure reduction, braking fluid inside a right front wheel FR wheel cylinder 2 is let flow into a reservoir via a flow passage 12 in a piston 11, while braking fluid inside a left rear wheel cylinder 3 is let flow into the reservoir via an orifice 15, so that a pressure reduction rate of the rear wheel cylinder 3 becomes lower than that of the front wheel cylinder 2. As the piston 11 is moved by means of a fluid pressure of a master cylinder while a pressurizing condition is accomplished again, the fluid pressure from the master cylinder is fed to the rear wheel cylinder 3 via a proportioning valve 5 and is fed to the front wheel cylinder 2 only via an orifice 13 formed in the piston 11. Therefore, a pressurizing rate to the front wheel cylinder 2 becomes lower than that to the rear wheel cylinder 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock brake device, and more particularly to a rear wheel cylinder in a depressurization mode during antilock control when simultaneously controlling diagonal wheels in a two-channel system of cross piping. The decompression rate of is set to be smaller than the decompression rate of the front wheel cylinder, and in the re-pressurization mode, the pressurization rate of the front wheel cylinder is set to be smaller than the pressurization rate of the rear wheel cylinder. The present invention relates to an anti-lock brake device that allows the rear wheel braking force to be used more effectively than the actual brake distribution.

[0002]

2. Description of the Related Art Conventionally, as an anti-lock brake device, a four-channel system for controlling all four wheels independently, a two-channel system for simultaneously controlling wheels on a diagonal line, and the like have been known. A modified example of is known.

For example, the anti-lock brake device disclosed in Japanese Patent Laid-Open No. 6-56014 is a typical example of a so-called cross piping two-channel system.
From the master cylinder to the left front wheel (F
L), the system leading to the right rear wheel (RR), and the right front wheel (FR),
It is composed of two systems leading to the left rear wheel (RL), and each system is provided with a hold valve, a decay valve, a reservoir, and a hydraulic pump driven by a motor M. The hold valve and the decay valve are designed to be controlled at a known timing by a command from an electronic control unit (not shown) when the wheel is locked.

In this two-channel system of cross piping, during normal braking, the hydraulic pressure from the master cylinder is supplied to the wheel cylinders via the piping and hold valves of each system so that the brake is applied.
Considering the stability of the vehicle during anti-lock control, the hold valve and decay valve are controlled to open and close by commands from an electronic control unit (not shown) based on the wheels with low wheel speeds for each system, and at the same time as this. The hydraulic pump sucks the brake fluid from the reservoir to reduce, hold, and pressurize the brake fluid pressure transmitted to the wheels in the same system to avoid the wheel lock state (diagonal select low). control).

[0005]

However, in the above-described two-channel system for cross piping,
For example, when the right front wheel becomes locked in a system consisting of the right front wheel and the left rear wheel, the left rear wheel is depressurized at the same time as the right front wheel with the wheel speed of the right front wheel as a reference (select low), and then repressurized It will be. However, in this depressurized state,
Since the pressure is reduced up to the left rear wheel that is not locked at the same pressure reduction rate as the right front wheel, the braking force of the left rear wheel cannot be effectively utilized. Also, when the same brake fluid pressure is supplied to the right front wheel and the left rear wheel that are easy to lock during re-pressurization, if a high fluid pressure is supplied, the right front wheel will re-lock, and conversely If the hydraulic pressure is low, the lock phenomenon of the right front wheel is avoided, but the braking force of the left rear wheel cannot be effectively used, and as a result, the braking force of the rear wheel cannot be effectively used. There is a problem that the braking distance becomes long.

Therefore, according to the present invention, in a two-channel system of cross piping, when the diagonal wheels are simultaneously subjected to select low control, the pressure reduction rate of the rear wheel cylinder is set to be lower than that of the front wheel cylinder in the pressure reduction mode during antilock control. In addition, in the re-pressurization mode, the front wheel cylinder pressurization rate can be made smaller than the rear wheel cylinder pressurization rate so that the rear wheel braking force is actually distributed during antilock control. The present invention aims to solve the above problems by providing a novel antilock brake device that can be effectively used.

[0007]

Therefore, the technical solution adopted by the present invention is a common hold valve for reducing, holding, and repressurizing the brake fluid pressure of the front wheel cylinder and the rear wheel cylinder of the same system. An anti-lock brake consisting of a two-channel system of cross piping having a decay valve and a reservoir for inflowing brake fluid from the wheel cylinder during anti-lock control and a hydraulic pump for pumping brake fluid from the reservoir and returning it to the master cylinder. In the system, when depressurizing during antilock control, the brake fluid in the rear wheel cylinder flows into the reservoir through the orifice, and during repressurization during antilock control, the brake fluid that is supplied to the front wheel cylinder passes through the orifice. Configured to supply It is a anti-lock braking system, characterized in that the.

[0008]

For example, in the system in which the right front wheel FR and the left rear wheel RL are paired, when the right front wheel FR is locked and the antilock control is started, the hold valve 6 is closed and the decay valve 7 is opened. The brake fluid in the front wheel cylinder 2 flows into the reservoir via the flow passage 12 of the piston 11, and the brake fluid in the left rear wheel cylinder 3 flows into the reservoir via the orifice 15. Thus, at the time of pressure reduction, the brake fluid of the rear wheel cylinder flows into the reservoir 9 via the orifice 15, so that the pressure reduction rate of the rear wheel cylinder is lower than that of the front wheel cylinder.

When the pressure is reduced, the master cylinder hydraulic pressure> the front wheel cylinder, so the orifice forming mechanism 4
The piston 11 inside moves to the right in the figure against the urging force of the spring 14, and the front wheel cylinder side and the hold valve 6 form an orifice 13 formed in the piston 11.
The communication is established via the chisel. When the pressure reducing state is changed to the re-pressurizing state, the hold valve 6 is opened and the decay valve 7 is closed, so that the hydraulic pressure from the master cylinder is supplied to the rear wheel cylinder 3 through the proportioning valve 5. Also, it is supplied to the front wheel cylinder 2 via an orifice 13. As a result, the rate of pressurization of the front wheel cylinder 2 becomes lower than the rate of pressurization of the rear wheel cylinder, and the pressure is applied slowly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an antilock brake device according to a first embodiment of the present invention. It should be noted that the drawing shows the brake piping system of one channel of the two channel system of cross piping, and the other piping system has the same configuration, so one brake piping system will be described here. Further, the electronic control device for controlling the valve is the same as the conventional one, and therefore the description thereof is omitted here.

In the figure, 1 is a master cylinder (M /
C), 2 is a front wheel cylinder, 3 is a rear wheel cylinder, the master cylinder 1 communicates with a hydraulic chamber 4a of an orifice forming mechanism 4 having a configuration described later, and a discharge port of a hydraulic pump 8 and a hold valve. 6
Is in communication with. In addition, the hold valve 6 is connected to the rear wheel cylinder 3 via the provoking valve 5.
Further, the front wheel cylinder 2 is communicated with the front wheel cylinder 2 through the orifice forming mechanism 4. Further, the rear wheel cylinder is connected to the decay valve 7 via the orifice 15.
Is in communication with. A passage between the orifice 15 and the decay valve 7 communicates with a passage 12 formed in a piston arranged in the orifice forming mechanism 4 via a check valve 10, and the decay valve 7 further includes a hydraulic pump 8
Communicates with the suction port and the reservoir 9.

A piston 1 having a flow passage 12 and an orifice 13 is provided in the main body of the orifice forming mechanism 4 described above.
1 is slidably arranged, and the piston 11 is configured so that the hydraulic pressure from the master cylinder acts on one side and the brake hydraulic pressure from the rear wheel cylinder acts on the other side. Is configured to be positioned on the left side in the figure by the biasing force of the spring 14. Channel 1
2 always connects the front wheel cylinder 2 and the check valve 10, and the orifice 13 is the spring 1
When it is located on the left side in the figure by the urging force of No. 4, the front wheel cylinder 2 communicates with the hold valve 6 via the orifice 13 and the peripheral passage 13a of the orifice, and the piston 11 urges the spring 14 When it moves to the right end against, the hold valve 6 and the front wheel cylinder 2 are communicated with each other only via the orifice 13.

The operation of the antilock control on the one system side having the above configuration will be described. [Normal Braking State] In FIG. 1, the orifice forming mechanism 4, the hold valve 6, and the decay valve 7 are maintained in the illustrated state. Therefore, the brake fluid from the master cylinder 1 is supplied to the rear wheel cylinder via the master cylinder 1 → the normally open type hold valve 6 → the proportioning valve 5 and also the hold valve 6
→ It is supplied to the front wheel cylinder 2 through the opening 13 of the orifice forming mechanism, so that the wheel can be braked. At this time, since the same hydraulic pressure acts on both end surfaces of the piston 11, the piston maintains the illustrated position by the urging force of the spring 14. When the brake is released, the brake fluid flows back to the master cylinder 1 via the passage opposite to the above.

[During Antilock Control] When the right front wheel FR is locked and the antilock control is started during traveling, the hold valve 6 is instructed by the electronic control unit.
Closes and the decay valve 7 opens. Then, the brake fluid in the right front wheel cylinder 2 flows into the reservoir via the flow path 12 of the piston 11 → the check valve 10 → the decay valve 7, and the brake fluid in the left rear wheel cylinder 3 is the orifice 15 → the decay valve. Flows into the reservoir via 7. Thus, at the time of pressure reduction, the brake fluid in the rear wheel cylinder flows into the reservoir 9 via the orifice 15, so that the pressure reduction rate of the rear wheel cylinder becomes lower than the pressure reduction rate of the front wheel cylinder, and the pressure is slowly reduced. (See Table 1).

As a result, a higher hydraulic pressure is maintained in the rear wheel cylinder for a longer time than in the front wheel cylinder, so that the braking force can be effectively utilized. When the pressure is reduced, the master cylinder fluid pressure> the front wheel cylinder. Therefore, the piston 11 in the orifice forming mechanism 4 moves to the right in the figure against the urging force of the spring 14, and the front wheel cylinder side and the hold valve. 6 is in communication with only the orifice 13 formed in the piston 11 (see FIG. 2).

When the depressurized state is changed to the re-pressurized state, the hold valve 6 is opened and the decay valve 7 is closed. Therefore, the hydraulic pressure from the master cylinder passes through the proportioning valve 5 to the rear wheel cylinder 3. Since the pressure is applied to the front wheel cylinder 2 via the orifice 13, the rate of pressurization to the front wheel cylinder 2 is lower than the rate of pressurization to the rear wheel cylinder, and the pressure is applied slowly. (See Table 1). As a result, the rate of increase in hydraulic pressure in the front wheel cylinder is lower than in the rear wheel cylinder,
The occurrence of front wheel lock is suppressed.

[0017]

[Table 1]

The above operation will be described with reference to the graphs of the relationship between brake fluid pressure and time in FIGS. In FIG. 3, the brake fluid pressure increases, and the proportion of the rear wheel cylinder decreases due to the action of the proportioning valve at point a. Wheel locking occurs at point b, and the brake fluid pressure in the front wheel cylinder and the rear wheel cylinder is reduced. At this time, the pressure reduction rate of the rear wheel cylinder is lower than the pressure reduction rate of the front wheel cylinder as described above, so that the pressure is slowly reduced. Then, when the pressure is re-pressurized at the point c, the pressure rate on the front wheel cylinder side becomes lower than the pressure rate on the rear wheel cylinder side, so that the pressure is applied more slowly than the rear wheel cylinder. After that, the holding of the brake fluid pressure and the re-pressurization are repeated as shown in FIG. 4, but since the pressurizing rate or the depressurizing rate as described above is selected at the time of repressurizing and depressurizing, it is shown by the dotted line in the figure The rear brake can be operated with a hydraulic pressure higher than the conventional rear brake hydraulic pressure, and the braking force can be effectively utilized. It should be noted that similar control is naturally executed in a system other than the system described above.

[0019]

As described in detail above, according to the present invention,
In a two-channel system with cross piping, if the diagonal wheels are simultaneously controlled to select low, the pressure reduction rate of the rear wheel cylinder can be made smaller than the pressure reduction rate of the front wheel cylinder in the pressure reduction mode during antilock control. In the re-pressurization mode, the pressure rate of the front wheel cylinder can be made smaller than the pressure rate of the rear wheel cylinder, so the braking force of the rear wheels can be used more effectively than the actual brake distribution during antilock control. The distance can be shortened. And so on.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an anti-lock control device according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view of an orifice forming mechanism.

FIG. 3 is a diagram showing a relationship between brake fluid pressure and time during antilock brake control.

FIG. 4 is an enlarged view of a main part of FIG. 3;

[Explanation of symbols]

 1 Master Cylinder 2 Front Wheel Cylinder 3 Rear Wheel Cylinder 4 Orifice Forming Mechanism 5 Proportioning Valve 6 Hold Valve 7 Decay Valve 8 Hydraulic Pump 9 Reservoir 11 Piston 12 Flow Path Formed in Piston 13 Orifice Formed in Piston 14 Spring 15 Orifice

Claims (4)

[Claims] 1. A common hold valve and a decay valve for reducing, holding, and repressurizing the brake fluid pressure of the front wheel cylinder and the rear wheel cylinder of the same system, and the brake fluid from the wheel cylinder at the time of antilock control. In the anti-lock brake device consisting of a two-channel system of cross piping having a reservoir that operates and a hydraulic pump that pumps the brake fluid from the reservoir and returns it to the master cylinder, the brake fluid in the rear wheel cylinder during decompression during anti-lock control The anti-lock brake device is configured to flow into the reservoir via the orifice and to supply the brake fluid to be supplied to the front wheel cylinder via the orifice when repressurizing during anti-lock control. 2. An orifice forming mechanism is provided in a flow path connecting the hold valve and the front wheel cylinder, and the orifice forming mechanism is such that the hydraulic pressure from the master cylinder is the hydraulic pressure from the rear wheel cylinder during antilock control. The antilock brake device according to claim 1, wherein the hold valve and the front wheel cylinder are configured to communicate with each other only through the orifice when the pressure exceeds a predetermined pressure. 3. The orifice forming mechanism is formed on the piston and a piston configured so that hydraulic pressure from a master cylinder acts on one side and brake hydraulic pressure from a rear wheel cylinder acts on the other side. When the brake fluid pressure from the flow passage that constantly communicates the front wheel cylinder and the decay valve and the master cylinder exceeds the brake fluid pressure of the rear wheel cylinder by a predetermined pressure or more, the piston is moved and the hold valve and the front wheel cylinder are connected. The anti-lock brake device according to claim 2, further comprising an orifice that forms a throttle therebetween. 4. The piston has a flow passage that constantly connects the front wheel cylinder and the decay valve, and an orifice that communicates with the flow passage. The orifice has a hydraulic pressure of the master cylinder that brakes the rear wheel cylinder. The anti-lock according to claim 3, wherein the piston moves when the pressure becomes equal to or higher than a predetermined pressure than the hydraulic pressure, and the hold valve and the front wheel cylinder are communicated with each other only through the orifice. Brake device.