JPH0550910A - Anti-lock liquid pressure control device - Google Patents

Abstract

PURPOSE:To independently control each wheel brake by storing working fluid discharged from a wheel brake in a reservoir at anti-locking time, and delivering the working fluid in the reservoir to the side of a wheel brake through a pump. CONSTITUTION:Each wheel. brake system for independent control is provided with cut-off valves 6A-6D to cut off communication between a master cylinder 1 and a wheel brake, and moreover pumps 10A-10D. The above plural pumps 10A-10D are driven by one motor 13, and quantities discharged from the pump differ above two kinds per unit stroke, and the discharged quantities returned to front and rear wheels are changed at fixed ratios.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-lock hydraulic pressure control device for an automobile, and more specifically, it discharges hydraulic fluid from a reservoir for storing hydraulic fluid discharged from a wheel brake during anti-lock to the wheel brake side during re-pressurization. In this type, it is possible to control each wheel brake independently.

[0002]

2. Description of the Related Art Conventionally, in an anti-lock hydraulic pressure control device provided in a brake circuit that connects a wheel brake and a master cylinder, a return passage for returning working fluid discharged from the wheel brake to the main passage at the time of anti-lock. Is provided
A discharge valve that is normally closed and opens during antilock in this return passage, a reservoir that temporarily stores the hydraulic fluid discharged from the wheel brakes, and a pump that discharges the hydraulic fluid in the reservoir to the master cylinder side or the wheel brake side. I have it.

The hydraulic fluid stored in the reservoir is generally put into practical use in a form of discharging it to the master cylinder side. On the other hand, a device is also proposed in which a shutoff valve that shuts off the communication between the master cylinder and the wheel brake is provided, and the hydraulic fluid in the reservoir is discharged from the shutoff valve to the wheel brake side by the pump and is returned to the wheel brake. Has been done. (JP-A-59-230853)

Comparing the above-mentioned type in which the hydraulic fluid in the reservoir is discharged to the master cylinder side with the type in which the hydraulic fluid is discharged to the wheel brake side, it is necessary to expect the maximum pressure of the master cylinder as the discharge pressure of the pump in the above type. On the other hand, in the type of discharging to the wheel brake side, which will be described later, the maximum pressure on the wheel brake side that does not cause wheel lock may be expected as the discharge pressure of the pump. for that reason,
There is an advantage that the drive source that defines the driving force of the pump, generally an electric motor, can be downsized.

[0005]

As described above, although the above-mentioned advantage is obtained in the type in which the hydraulic fluid in the reservoir is discharged to the wheel brake side, a problem arises when the plurality of wheel brakes are independently controlled. That is, in this type of anti-lock device, the pressure reduction of the wheel brake is achieved by opening the discharge valve.
Further, the pressure increase is realized by the discharge from the pump, but normally, assuming that the number of pumps driven by the electric motor is one for a plurality of wheels, the multi-wheel brake system communicates through the discharge port of the pump. To do. Therefore, it is impossible to independently reduce or increase the pressure of each wheel brake system.

The above-mentioned problem is that the shutoff valve of the main passage is provided on the wheel brake side from the branch point of each wheel brake system of the main passage, and the branch point of each return passage to each wheel brake system, the return passage and the main passage. By providing a check valve between the confluence with the passage, it is possible to prevent the wheel brake systems from communicating with each other. However, in this case, the distribution of the hydraulic fluid discharged from the pump depends on each wheel brake pressure. Normally, the rigidity of the wheel brakes differs greatly between the front and rear wheels, so it is desirable to change the ratio of the amount of liquid discharged to the wheel brakes between the front and rear wheels. Since it is impossible to control the wheels differently, it becomes difficult to obtain good control performance.

The present invention is intended to solve the above-mentioned problems, and allows each wheel brake to be independently controlled while adopting a type in which the hydraulic fluid in the reservoir is discharged to the wheel brake side. The amount of hydraulic fluid discharged to the front and rear wheels can be controlled to a suitable ratio.

[0008]

That is, according to the present invention, a pump for discharging hydraulic fluid in a reservoir to the wheel brake side and a shutoff valve for shutting off communication with a master cylinder are provided by the number of independently controlled brake systems. It is provided so that the brake system can be controlled independently.

Specifically, the hydraulic fluid discharged from the wheel brake is branched from the main passage communicating the master cylinder and each wheel brake and the main passage near the wheel brake side to a point upstream from the branch point. An independent recirculation passage for each wheel brake that recirculates, a discharge valve that is normally closed for each of the above recirculation passages, and that is sequentially closed from the wheel brake side. Each of the wheels is equipped with a reservoir that is stored in the valve, a pump that is driven during antilock, and a shutoff valve that is installed in each main passage on the master cylinder side from the confluence point of the above-mentioned return passages and that is normally open and closed during antilock. (EN) An anti-lock hydraulic pressure control device configured to independently recirculate pump discharge liquid to the wheel brake side at the time of anti-lock.

Further, according to the present invention, as described above, the brake systems for independently controlling the pumps are independently provided, and
While driving these multiple pumps with one electric motor, the discharge amount per unit stroke of each pump is made different, and the ratio of the liquid discharged from each pump is set to a suitable constant ratio between the front and rear wheels. Therefore, good control performance is obtained.

In order to make the discharge amount per unit stroke of the pump different, an eccentric cam having the same eccentric amount is connected to the output shaft of one electric motor, and the plunger of the pump reciprocated by these eccentric cams is connected. The diameters of the front and rear wheels are different, the plunger diameter on the front wheel side is larger than the plunger diameter on the rear wheel side, and the discharge amount on the front wheel side per unit stroke is larger than that on the rear wheel side. The plunger diameter may be the same and the eccentric amount of the eccentric cam may be different.

[0012]

As described above, since the shut-off valve that shuts off the communication with the master cylinder side is provided for each independently controlled brake system, the master cylinder pressure is shut off from acting on all-wheel brakes, and the brake system is cut off. Each can be controlled independently. Also, since the ratio of the pump discharge liquid can be kept constant,
The ratio of the discharged liquid can be controlled to be suitable between the front and rear wheels.

[0013]

The present invention will now be described in detail with reference to the embodiments shown in the drawings. In FIG. 1, 1 is a master cylinder, 2
A and 2B are front wheel brakes, 3A and 3B are rear wheel brakes, and the master cylinder 1 and front and rear wheel brakes are X pipes. That is, the front wheel brake 2A on the right side, the rear wheel brake 3B on the left side and the master cylinder 1 are divided into two main passages 4A from a passage 4 having one end communicating with a master cylinder chamber (not shown) of the master cylinder 1, The other end of 4B communicates with the front wheel brake 2A and the rear wheel brake 3B, respectively. In addition, the left front wheel brake 2B and the right rear wheel brake 3A
The master cylinder 1 and the master cylinder 1 are divided into two main passages 5A and 5B which are branched from the passage 5 having one end communicating with a hydraulic boost chamber (not shown) of the master cylinder 1 and the other end is a front wheel brake 2B and a rear wheel brake 3A. To each of them.

Each of the main passages 4A, 5A, 4B and 5B is provided with normally open shutoff valves 6A to 6D which are electromagnetic valves. Further, the recirculation passages 7A to 7D are branched from the position P1 close to the wheel brake communication side of each of the main passages 4A to 5B, and the other ends of the recirculation passages 7A to 7D are isolated from the shutoff valves of the main passages 4A to 5B, respectively. 6A to 6D are joined at a position P2 on the downstream side of the installation position. In the main passages 5A and 5B on the rear wheel brake side, the proportional pressure reducing valve 1 is provided between P1 and P2.
6A and 16B are provided.

In the respective return passages 7A to 7D, the normally closed discharge valves 8A to 8D, which are electromagnetic valves, and the hydraulic fluid discharged from the wheel brakes are sequentially temporarily accumulated from the branch position P1 to the merging position P2. Reservoirs 9A to 9D and plunger type pumps 10A to 10D are provided.

The discharge valves 8A to 8D are opened at the time of antilock, and the resistance at the time of opening the valve is set small.

The pumps 10A to 10D are provided with relief valves 11A to 11D and 12A to the suction side and the discharge side, respectively.
12D is attached. In addition, the pumps 10A-1
0D is driven by one electric motor 13, and two eccentric cams 14A and 14B having the same eccentric amount are fixed to the output shaft 13a of the motor 13. One of the above eccentric cams 1
The plungers 15A and 15B of the pumps 10A and 10B on the front wheels are operated at both ends of 4A, and the other eccentric cam 1
4B, rear wheel side pump 10C, 10D plunger 15
C and 15D are operating.

The front wheel side plungers 15A and 15 described above
The diameter of B is set larger than the plungers 15C and 15D on the rear wheel side. Therefore, the discharge liquid amount of the pump per unit stroke of the plunger is set so that the front wheel side becomes larger than the rear wheel side at a constant ratio.

Next, the operation of the above device will be described. The state shown in the figure shows a state in which normal shut-off valves 6A to 6B are open and discharge valves 8A to 8D are closed and the brake fluid is applied from the master cylinder 1 through the main passages 4A to 5B. 2A to 3B.

If the control device (not shown) determines that one or more wheels tend to lock due to the information from the wheel speed sensor (not shown) and it is necessary to reduce the brake pressure, the pressure is reduced. The shutoff valves 6A to 6B of the power brake system are selected and opened, and the discharge valves 8A to 8B are selected and opened. Therefore, the hydraulic fluid for the wheel brakes of the brake system to be depressurized is drained to the reservoir through the recirculation passage, and the brake pressure can be reduced only for the wheels of the brake system to be depressurized. For example, when all the front and rear wheels and the left and right wheels tend to lock, the hydraulic fluid of all wheel brakes 2A to 3B is discharged and temporarily stored in the reservoirs 9A to 9D.
When only the front wheel brakes 2A, 2B tend to lock, the shutoff valves 6A, 6B close and the discharge valves 8A, 8B open.
The brake pressure of the front wheel brakes 2A, 2B is reduced.

At the same time, the electric motor 13 is driven,
The plungers 15A-15D of the pumps 10A-10D are activated. By this pump operation, the hydraulic fluid stored in the reservoirs 9A to 9D is supplied from the return passages 7A to 7D to the shutoff valve 6
It is led to the main passages 4A to 5B downstream of A to 6D and is returned to the wheel brakes 2A to 3B side. The hydraulic fluid circulated to the wheel brakes 2A to 3B is discharged to the discharge valves 8A to 8D.
Since the resistance when the valve is opened is small, it flows back from the branch point P1 to the side of the return passages 4A to 5B, and the wheel brakes 2A to 3A.
It is possible to keep the pressure of the wheel brakes 2A to 3B sufficiently small without introducing it to the B side.

When the tendency to lock the wheels disappears and it becomes necessary to re-pressurize the wheel brake pressure, the discharge valves 8A to 8D that have been opened are closed. At that time, the shut-off valve 6A which was closed until the re-pressurizing operation after the anti-lock operation is completed.
6D has not opened yet, repressurization is completed and pump 10A
To 10D, the shutoff valves 6A to 6 only after the driving of 10D is stopped.
Do not open D.

Therefore, the discharge valves 8A to 8D and the shutoff valve 6
Wheel brake pressure is re-pressurized with A-6D closed together. That is, the motor 1 is attached to the pumps 10A to 10D.
An amount of hydraulic fluid commensurate with the rotation of No. 3 is discharged from the reservoirs 9A to 9D to the wheel brakes 2A to 3B, and the brake pressure is increased.

At the time of re-pressurization, each wheel brake system is
Since the pumps 10A to 10D are independently provided and the shutoff valves 6A to 6D are provided in the respective main passages 4A to 5B, the hydraulic fluid discharged from the pumps does not flow into other brake systems, Only flows into the corresponding wheel brakes. Moreover, in the pumps 10A to 10D, the diameters of the front wheel side plungers 15A and 15B are set to the rear wheel side plungers 15C and 1D.
Since the diameter is larger than the diameter of 5D, and the discharge amount per unit stroke is increased from the front wheel side to the rear wheel side at a constant ratio, the amount of hydraulic fluid flowing into the front wheel brakes 2A and 2B is set to the rear wheel brake 3.
It becomes larger than A and 3B at a constant rate. As described above, the rigidity of the front wheel brakes 2A, 2B and the rear wheel brakes 3A, 3B is set so that the rigidity on the front wheel side is larger than that of the rear wheel brakes, so that the amount of inflow to the front wheel brakes 2A, 2B is reduced. By increasing more than 3A and 3B, the pressure increasing speeds of the front wheel brake and the rear wheel brake can be made almost the same.

When the re-pressurization after releasing the antilock is completed, the motor 13 is stopped and the discharge from the pumps 10A to 10D is stopped, and at the same time, the shutoff valves 6A to 6D which are closed.
Opens and returns to the normal state shown.

The means for making the discharge amounts of the pumps 10A to 10D different between the front wheel side and the rear wheel side is the plunger 15A.
~ 15D diameter is different, plunger 15A ~
The diameters of 15D may be the same, and the eccentric amounts of the eccentric cams 14A and 14B that operate the plungers 15A to 15D may be different. That is, the eccentric amount of the eccentric cam 14A on the front wheel side is increased and the eccentric amount of the eccentric cam 14B is set to be small, so that the discharge amount per unit stroke is constant in the front wheel side pumps 10A, 10B than in the rear wheel side pumps 10C, 10D. It can be increased in proportion. If necessary, four eccentric cams may be attached to the output shaft of the motor, and one plunger may be operated by each eccentric cam to change the discharge amount per unit of each pump.

[0027]

As is apparent from the above description, in the anti-lock hydraulic pressure control device according to the present invention, pumps and shutoff valves are provided by the number of independently controlled systems, and, for example, all wheel brakes are independently controlled. In this case, since the pump and the shutoff valve are independently provided in each wheel brake system, each wheel brake can be controlled independently even when the pump discharge liquid is returned to the wheel brake side.

Further, since the pumps provided by the number of independently controlled systems are driven by one motor, the cost does not increase significantly. In addition, since the amount of hydraulic fluid discharged from the pump is made different in two or more ways even though it is driven by one motor, the ratio of the amount of discharged fluid between the front and rear wheels should be optimized. Can be done. Therefore, the antilock hydraulic pressure control device of the type in which the liquid discharged from the pump is circulated to the wheel brake side from the shutoff valve can be made practical, and the cost reduction can be enjoyed by reducing the pump load.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 master cylinder 2A, 2B front wheel brake 3A, 3B rear wheel brake 4A, 4B, 5A, 5B main passage 6A-6D shutoff valve 7A-7D recirculation passage 8A-8D exhaust valve 9A-9D reservoir 10A-10D pump 13 electric motor 14A , 14B Eccentric cam 15A-15D Plunger

Claims (2)

[Claims] 1. A main passage communicating between a master cylinder and each wheel brake, and a main passage near the wheel brake, branched from the main passage, and hydraulic fluid discharged from the wheel brake is returned to an upstream point from the branch point. An independent recirculation passage for each wheel brake, a discharge valve that is normally closed independently for each of the above-mentioned recirculation passages, and that is normally closed and opens during antilock, and a reservoir that temporarily stores the discharged hydraulic fluid. , And an anti-lock drive pump, and a shut-off valve that is normally open and closes in the anti-lock state and is installed in each main passage on the master cylinder side from the confluence point with the above-mentioned return passages. The anti-lock hydraulic pressure control device is configured to recirculate the pump discharge liquid to the wheel brake side during anti-lock. 2. The antilock according to claim 1, wherein the pump provided for each wheel brake is driven by one motor and the discharge amount per unit stroke of each pump is made different. Hydraulic control device.