JPH06263017A - Braking force control device - Google Patents

Abstract

PURPOSE:To provide a braking force control device which is provided with the TCS function together with the ABS in a simple and inexpensive manner without increasing the weight and the space. CONSTITUTION:A braking force control device is provided with a master cylinder(M/C) 2, wheel cylinders(W/C) 1a, 1b, e.g. intensifying and pressure reducing control valves 4a-5b, and a circulating pump 6, and a cut valve 21 is provided between the M/C and a control valve, and a liquid pool 71 is provided in a reservoir 7 of the return oil passage 11R of the control valves and the pump. During the TCS operation, the M/C is shut off from the hydraulic circuit 10 by the cut valve 21. In the reservoir, the brake fluid in the W/C which is discharged when the W/C is pressure-reduced can not reach the pump, and held once, and the liquid in this liquid pool 71 becomes the brake fluid to be supplied to the W/C when the W/C pressure is increased. This constitution is substantially same as the increased diameter of the pipe passage leading from the W/C to the pump so as to be capable of supplying when the W/C pressure is increased, and the TCS function is easily incorporated without increasing the weight and the space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking force control device, and more particularly to a braking force control device capable of traction control by anti-skid and braking force.

[0002]

2. Description of the Related Art As a conventional braking force control device, for example,
There is one disclosed in Japanese Patent Laid-Open No. 2-18150. This is a brake control device in which a braking force control device having a so-called anti-skid function for preventing wheel locks is provided with a traction function for suppressing slip of driving wheels during acceleration or the like.

That is, in a braking force control device having only an anti-skid circuit, an electromagnetic valve that connects and disconnects the wheel cylinder and the master cylinder and switches the brake fluid in the wheel cylinder to be discharged to the reservoir, and the reservoir. It is composed of a hydraulic pump that returns the discharged brake fluid to the master cylinder, and it is possible to increase or decrease the wheel cylinder pressure of the control target wheel by pressure control using the master cylinder pressure as the original pressure, but as it is, the wheel cylinder Since the pressure cannot exceed the master cylinder pressure, a cut valve that shuts off the master cylinder and the anti-skid circuit is provided, and a pipe line system communicating with the master cylinder is installed on the suction side of the hydraulic pump separately from the anti-skid circuit. It is provided. By doing so, the cut valve cuts off the communication between the master cylinder and the anti-skid circuit, and the brake fluid is directly supplied from the master cylinder to the wheel cylinders via the hydraulic pump, thereby enabling the pressure increase control.

[0004]

However, in the above-described conventional braking force control device, in order to achieve the traction function, a pipe line must be provided separately from the antiskid circuit, and the weight increases, Moreover, there is a problem in that it is disadvantageous in terms of space.

The present invention has been made in view of the above points, and it is possible to increase weight and space without increasing the weight.
An object of the present invention is to provide a braking force control device having a traction function simply and inexpensively.

[0006]

According to the present invention, the following braking force control device is provided. It includes a master cylinder, a wheel cylinder, a pressure control valve for controlling the wheel cylinder pressure, and a circulation pump, the master cylinder is connected to a first port of the pressure control valve, and the circulation pump sucks its suction port. Between the master cylinder and the pressure control valve, the discharge side is connected to the oil passage connected to the second port of the pressure control valve, and the discharge side is connected to the oil passage connected to the first port of the pressure control valve. A braking force control device having an on-off valve and a reservoir in the second port of the pressure control valve and the return oil passage of the circulation pump, and in the above, the reservoir is The braking force control device is characterized in that a part of the outer shell is made of an elastic body, and its volume is made variable by an internal pressure.

[0007]

According to the present invention, an opening / closing valve is provided between the master cylinder and the pressure control valve, and a reservoir of the reservoir is provided in the second port of the pressure control valve and the return oil passage of the circulation pump. Skid control and traction control are performed. During traction control, an on-off valve shuts off the master cylinder. The reservoir of the return oil passage is for temporarily holding the brake fluid in the wheel cylinder that is discharged when the wheel cylinder is depressurized and cannot reach the circulation pump. The brake fluid is supplied to the wheel cylinder when the wheel cylinder pressure is increased. in this case,
The liquid pool acts substantially in the same manner as making the diameter of the pipe line from the wheel cylinder to the circulation pump thick enough to supply the pressure to the wheel cylinder when the pressure is increased. While avoiding the disadvantage of weight and space, it is possible to easily incorporate the traction function without increasing the weight and space to realize this.

According to the first aspect of the present invention, the liquid reservoir can be made smaller, and the reservoir portion can be simply structured to communicate with the atmosphere. Similarly, the circulation pump can be used without changing the piping. The brake fluid pressure required to pressurize the wheel cylinder during driving can be easily supplied to the wheel cylinder.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, 1a and 1b are wheel cylinders for the left and right drive wheels of the vehicle, 2 is a brake pedal, and 3 is a master cylinder. In the figure, the portion of the brake hydraulic system from the master cylinder to the wheel cylinder is the drive wheel system side when the front wheels or the rear wheels are the drive wheels, or the front wheels and the rear wheels are the drive wheels. The configuration on the side of one of the drive wheels in that case is shown. Both hydraulic pressure outlet ports of the master cylinder 3 operated by stepping on the brake pedal 2.
Are connected to a front wheel brake hydraulic system and a rear wheel brake hydraulic system, and one of the illustrated outlet ports A is connected to the wheel cylinders 1a, 1a on the left and right sides of the drive wheel.
Connect to the brake hydraulic system according to b.

In such a brake hydraulic system, the circuit portion of the reference numeral 10 which is surrounded by the one-dot chain line in the drawing up to the wheel cylinders 1a and 1b is a known anti-roll except for a reservoir of the reservoir which will be described later. It may have the same structure as the skid (ABS) hydraulic circuit. That is, it is a hydraulic control circuit used in an anti-skid hydraulic system for individually anti-skid controlling the left and right wheels to be controlled, and includes a pressure control valve and a circulation pump, etc., which can individually control the hydraulic pressure of the wheel cylinders 1a and 1b. Can be composed of

The hydraulic circuit 10 here individually controls the brake pressure of each of the left and right wheels, and includes a pressure increasing control valve 4a and a pressure reducing control valve 5a for switching each of the two positions for one of the left and right wheels. 2 each for the set and the other wheel of the left and right wheels
A pressure control valve is provided with a hydraulic control valve of a combination of a position switching pressure increasing control valve 4a and a pressure reducing control valve 5a, and a circulation pump 6 and a reservoir 7 common to the left and right wheels and check valves 8, 9a, 9b. And these are connected by piping as shown in the figure. Further, a cut valve 21 is provided between the master cylinder 3 and the hydraulic circuit 10, and a fail-safe check valve 22 is arranged in parallel with the cut valve 21.

The hydraulic circuit 10 and the piping connection between the hydraulic circuit 10 and the master cylinder 3 can be configured as follows. That is, master cylinder outlet port A
Through the cut valve 21 in the oil passage 11A, the oil passage 11B
1 and 11B2 are connected to the ports B1 and B2 of the pressure increase control valves 4a and 4b. The ports D1 and D2 of the pressure reducing control valves 5a and 5b are the ports C of the pressure increasing control valves 4a and 4b.
1, C2 to the respective wheel cylinders 1a, 1b are connected to the branched oil passages of the oil passages 11W1, 11W2 (wheel cylinder hydraulic oil passages), so that each wheel cylinder 1a,
It is connected to ports W1 and W2 of 1b.

Further, the respective oil passages 11W1 and 11W2 are
Each of the branch points H1 and H1 on the way is connected to a branch portion J on the way of the oil passages 11A-11B1 and 11B2 via check valves 9a and 9b. Further, each pressure reducing control valve 5
The return ports E1 and E2 of a and 5b pass through the return oil passage 11R and the intake port 6 of the reservoir 7 and the circulation pump 6.
connected to a. Here, the reservoir 7 has a liquid pool 71. That is, in the present embodiment, the return oil passage 11R between the return ports E1 and E2 of the pressure reducing control valves 5a and 5b and the circulation pump 6 has the liquid pool 71. The reservoir 7 is for temporarily holding the brake fluid in the wheel cylinder that is discharged when the wheel cylinder is depressurized. Preferably, in this case, a part of the outer portion of the liquid reservoir provided in the reservoir 7 is made of an elastic body, and its volume is made variable by the internal pressure.

FIG. 2 is a detailed structural diagram of an example of the liquid pool portion of the reservoir 7. The reservoir 7 is attached to the outer wall 15 of the ABS unit, and as shown in the drawing, a part of the outer contour of the liquid pool 71 of the reservoir 7 is formed of an elastic body 72 (diaphragm). Further, in the present example, the left chamber in the drawing of the elastic body 72 is opened to the atmosphere through the atmosphere communication port 74 opened in the piston shaft 73 of the reservoir 72. Thus, the opposite side of the liquid pool 71 is in communication with the atmosphere.

Returning to FIG. 1, the discharge port 6 of the circulation pump 6
b is connected to the branch portion J of the oil passage between the master cylinder 2 and the pressure increase control valves 5a and 5b via the check valve 8.
An oil passage 11G is connected to the branch portion J in parallel with the cut valve 21 via the fail-safe check valve 22 in the oil passage. In FIG. 1, as described above, the portion surrounded by the alternate long and short dash line has almost the same structure as the case of the conventional anti-skid device using the two-position switching control valve except for the liquid pool portion of the reservoir 7. As will be mentioned later, a 3-port 3-position control valve may be used as the pressure control valve.

In this embodiment, the master cylinder 3, the wheel cylinders 1a and 1b, the pressure increasing control valves 4a and 4b as pressure control valves, and the pressure reducing control valve 5a are thus provided.
5b, a circulation pump 6 and a reservoir 7, and the master cylinder 3 is provided with ports B1 and B2 of the pressure increasing control valves 4a and 4b.
And the circulation pump 6 has an oil passage 11 connecting the suction port 6a side to the ports E1 and E1 of the pressure reducing control valves 5a and 5b.
R is an oil passage oil passage 11A-1 whose discharge port 6b side is connected to the ports B1 and B2 of the pressure increase control valves 4a and 4b.
1B1 and 11B2, and a cut valve 2 as an on-off valve connected between the master cylinder 3 and the pressure increase control valves 4a and 4b.
1, and the liquid reservoir 71 is provided in the ports E1 and E1 of the pressure reducing control valves 5a and 5b and the return oil passage 11R of the circulation pump 6.

Pressure increasing control valves 4a, 4b, pressure reducing control valves 5a,
The controller 31 controls the opening and closing of 5b and the cut valve 21.
The wheel speed sensor 3
The controller 31 executes the anti-skid control and the traction control control by the brake based on the input information from the wheel speed sensor 32.

These controls will be described below. First, the anti-skid control is as follows.
Each control valve 4a, 4b, 5a, 5b as a pressure control valve
Is normally in the switching position shown, and the cut valve 21 between the master cylinder 3 and the control valve is also in the open state shown. In the figure, the master cylinder hydraulic pressure generated by the depression of the brake pedal 2 is now shown in the wheel cylinder 1.
When the controller 31 judges the slip ratio of the vehicle by the signal from the wheel speed sensor 32 during braking by acting on a and 1b, the pressure increase control valves 4a and 4b of the corresponding wheels are switched from the positions shown in the drawings and closed. , The pressure reducing control valves 5a and 5b are switched from the positions shown in the figure to open them (note that in the following, the reference numerals of the pressure increasing control valve and the pressure reducing control valve are simply 4, 5).
Also, the same applies to other elements as well.) As a result, the hydraulic pressure in the wheel cylinder 1 passes through the path of the oil passage 11W-branch point H-return port E of the pressure reducing valve 5, and falls to the reservoir 7 via the return oil passage 11R.

Simultaneously with the slip judgment of the controller 31, the circulation pump 6 is rotated, and the liquid accumulated in the reservoir 7 is re-supplied to the master cylinder 3 or the pressure increasing control valve 4 through the check valve 8. -Kikyu flows around the oil passage in the J part of the branch portion, and is used when the master cylinder hydraulic pressure is generated and braking is performed, and when the own wheel or another wheel is boosted again from the depressurization in the anti-skid cycle. In this case, since the cut valve 21 is in the open position shown in the drawing, there is no difference from the conventional anti-skid device during braking. To prevent wheel lock during braking, the anti-skid function is exhibited by repeating the skid cycle, in which the pressure is reduced if the wheels are likely to lock and the pressure is increased when the wheel speed recovers.

When the brake pedal 2 is released, the hydraulic pressure accumulated in the wheel cylinder 1 is quickly released to the master cylinder 3 through the path of the oil passage 11W-branch point H-check valve 9-cut valve 21 in the open state. To be done.

Next, the traction control control by the brake will be described. In this embodiment, the ABS circuit portion of the wheel lock prevention control during braking is extremely effectively used, and the cut valve 21 is closed during drive slip control.
Only by rotating the circulation pump 6, the liquid in the liquid pool 71 provided in the reservoir 7 is sucked out, and the wheel cylinder 1 is pressurized. Then, after that wheel cylinder 1
The pressure control can be performed by the ABS pressure control valve.

Now, in the figure, at the time of starting or accelerating, the controller 3 is operated by a signal from the wheel speed sensor 32.
When 1 determines the slip of the drive side wheel, the cut valve 21
Is switched from the position shown in the drawing to close, and the circulation pump 6 is started. The circulation pump 6 pumps up the liquid accumulated in the liquid pool 71 of the reservoir 7, and because the cut valve 21 is closed, the wheel of the wheel slipping along the oil passage of the check valve 8-oil passage 11B-oil passage 11W. Increase the pressure of cylinder 1,
Stop the drive slip.

In this way, it is possible to provide a traction function for suppressing the slip of the drive wheels during acceleration or the like. Here, as for the liquid pool 71 of the reservoir 7, as described above, in the reservoir of the return oil passage, the brake fluid discharged from the wheel cylinder during the pressure reduction of the wheel cylinder cannot reach the hydraulic pump. ,
This is for holding once, but in this configuration,
The liquid in this portion of the liquid pool 71 provided in the reservoir 7 becomes the brake liquid that is supplied to the wheel cylinder 1 when the pressure in the wheel cylinder 1 is increased. That is, this is substantially the same as in FIG. 1, the pipe line from the wheel cylinders 1a and 1b to the circulation pump 6, which is a hydraulic pump, is made thick enough to be supplied when the pressure is increased in the wheel cylinder 1. It means that if the pipe is actually thickened, it is disadvantageous in terms of weight and space, but in the present embodiment, the above is avoided by avoiding this. Without increasing the space
A braking force control device having a traction function can be obtained.

More specifically, in FIG. 1, the master cylinder 3 and the anti-skid hydraulic circuit 10 are cut off during the drive wheel slip suppression control, but the pipe line in that hydraulic circuit portion is actually thick. It is possible to effectively utilize this without installing the traction function, and to easily incorporate the traction function.To achieve the traction function like the conventional braking force control device shown above, a pipe line is provided separately from the anti-skid circuit. Therefore, the problem of increased weight, increased cost, and space disadvantage is solved well. Thus, both the anti-skid and traction functions are achieved by the above configuration. Even in the conventional anti-skid circuit, the cut valve 21 and the liquid pool 7 in the reservoir 7 are basically based on this.
By adding 1, the drive slip control can be easily realized, and it has a different hydraulic source and a hydraulic switching valve as in the prior art, or a hydraulic system configuration for switching a complicated oil passage is expensive. It is never composed. It is desirable that the liquid pool 71 is sufficiently large so that a large negative pressure does not occur in the suction oil passage system of the circulation pump, and that the circulation pump has sufficient self-priming performance. The subsequent pressure control by the traction control is the same as in the case of the anti-skid control.

In addition, it goes without saying that the brake pressure can be increased via the fail-safe check valve 22 in the case of a failure such as when the cut valve 21 is stuck in the closed state in the above-mentioned configuration.

Further, in the above, it is more effective to use the structure shown in FIG. 2 as the reservoir 7 having the liquid pool 71. As mentioned above, in the reservoir 7 of FIG. 2, a part of the outer contour of the liquid pool 71 is composed of the elastic body (diaphragm) 72, and the left side of the elastic body 72 is opened by the reservoir piston shaft 73. It is opened to the atmosphere through the atmosphere communication port 74. As described above, the liquid in the liquid pool 71 of the reservoir 7 becomes the brake liquid supplied to the wheel cylinder 1 when the wheel cylinder pressure is increased. In this case, one of them is set to the atmospheric pressure as shown in FIG. As a result, the wheel cylinder pressure can be easily supplied to the wheel cylinder when the pressure is increased.

That is, when the circulation pump 6 is rotated at the start of the drive slip control by the controller 31, the liquid in the liquid pool 71 is sucked and the return oil passage 11R system tends to have a negative pressure, the left side of the elastic body 72 communicates with the atmosphere. Therefore, by moving to the right in the figure and decreasing the volume of the liquid pool 71,
It works so as not to generate negative suction pressure of the circulation pump 6. Therefore, in this configuration, the liquid pool 71 can be downsized because there is a sufficient volume necessary for pressurizing the wheel cylinder 1, and the circulation pump does not require strict self-priming performance. There is an advantage that it is not necessary to provide a special structure such as providing a pump.

Further, in the present embodiment, the control valve is divided into two types, a pressure increasing control valve and a pressure reducing control valve, as shown in the figure. However, as mentioned above, the same applies even if a 3 port 3 position control valve is used. Needless to say. Even in this case, it is possible to provide a conventional anti-skid hydraulic system using the 3-port 3-position control valve without a switching valve for switching a special oil passage by additionally providing a special oil passage or a separate hydraulic source. Needless to say, the drive slip control device can be constructed at a very low cost.

[0029]

According to the invention described in claim 1 of the present invention,
Not only anti-skid control, but also traction control control with a brake is possible with a simple configuration and control.
A braking force control device having both anti-skid and traction functions can be realized extremely easily and inexpensively without increasing weight and space. Further, the liquid pool in the return oil passage can be made smaller by configuring the liquid storage device according to the second aspect, and the brake liquid required to pressurize the wheel cylinder when the circulation pump is driven. The pressure can be easily supplied to the wheel cylinder, and also in this respect, the increase in weight and space can be prevented and effectively avoided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a braking force control device according to an embodiment of the present invention.

FIG. 2 is a detailed structural diagram of an example of an applicable reservoir.

[Explanation of symbols]

 1a, 1b Drive wheel wheel cylinder 2 Master cylinder 3 Brake pedal 4a, 4b Pressure increase control valve 5a, 5b Pressure reduction control valve 6 Circulation pump 6a Suction port 6b Discharge port 7 Reservoir 8, 9a, 9b Check valve 10 Anti-skid hydraulic circuit 11A Oil passage 11B1, 11B1 Oil passage 11G Oil passage 11R Return oil passage 11W1, 11W1 Oil passage 15 ABS unit outer wall 21 Cut valve 22 Fail-safe check valve 31 Controller 32 Wheel speed sensor 71 Liquid pool 72 Elastic body 73 Reservoir piston 74 Atmosphere communication Port B1, B2, C1, C2 Pressure increasing control valve port D1, D2, E1, E2 Pressure reducing control valve port W1, W2 Wheel cylinder port

Claims (2)

[Claims] 1. A master cylinder, a wheel cylinder, a pressure control valve for controlling the wheel cylinder pressure,
A circulation pump, the master cylinder is connected to a first port of the pressure control valve, and the circulation pump has an intake side thereof in an oil passage connected to a second port of the pressure control valve and a discharge side thereof. Are respectively connected to oil passages connected to the first port of the pressure control valve, and an opening / closing valve is provided between the master cylinder and the pressure control valve, and a second port of the pressure control valve and the circulation pump are connected. A braking force control device having a reservoir in the return oil passage. 2. The braking force control device according to claim 1, wherein a part of an outer shell of the liquid pool is made of an elastic body, and a volume of the liquid pool is variable by an internal pressure.