KR100344471B1 - Anti-lock brake system for vehicle - Google Patents

Abstract

PURPOSE: An anti-lock brake system of a vehicle is provided to reduce pressure of oil drastically pumping from first and second low-pressure accumulators with a single high-pressure accumulator, and to decrease parts with compact structure. CONSTITUTION: An outlet hydraulic line of a first pump(71) and a second pump(72) is connected to an inlet hydraulic line(80a) of a high-pressure accumulator(80), and an outlet hydraulic line(80b) is connected to a hydraulic line of a master cylinder(30) and front and rear wheel brakes. Pulsation of pressure discharged from first and second pumps is reduced by the high-pressure accumulator. Parts are reduced, and the size of the modulator is decreased with compact structure.

Description

Automotive Antilock Brake System

The present invention relates to a vehicle anti-lock brake system, and more particularly, to a high-pressure accumulator in which the normal-closed solenoid valve is opened and the oil discharged from each brake is temporarily stored by the pump operation.

Vehicles are equipped with a brake system for braking. Recently, various kinds of systems have been proposed for obtaining a stronger and more stable braking force. Among them, the anti-lock brake system exhibits the most advanced effect. FIG. 1 is a schematic diagram showing a general configuration of such an anti-lock brake system.

The conventional anti-lock brake system is a drum or caliper hydraulic brakes 9a, 9b, 9c, and 9d that generate braking force by hydraulic pressure to the front wheels FL, FR and the rear wheels RL and RR, respectively, as shown therein. It is installed and consists of a master cylinder (3) provided with a hydraulic power storage device (1a) and an oil storage tank (3a) for forming a braking hydraulic pressure to deliver to the brakes (9a, 9b, 9c, 9d).

The power booster 1a is a device that generates a large braking force with a small force by using a pressure difference between the vacuum and the atmosphere, and is operated by being linked with the brake pedal 1 provided in the driver's seat. The master cylinder 3 receives the amplified force from the power booster 1a to form a braking hydraulic pressure, and is connected to each of the brakes 9a, 9b, 9c, and 9d through a hydraulic line.

On the other hand, solenoid valves are provided on the inlet and outlet sides of the brakes 9a, 9b, 9c, and 9d to control the hydraulic pressure transmitted to the brakes 9a, 9b, 9c, and 9d. This is divided into normal-open solenoid valves 5a, 5b and 5c disposed at the inlet side and normal-closed solenoid valves 4a, 4b and 4c disposed at the outlet side and controlled by the electric control unit ECU 2 This results in a strong and stable braking force. At this time, the electric controller 2 detects the vehicle speed through the wheel sensors 2a provided on the front wheels FR and FL and the rear wheels RR and RL, and controls them.

First and second low pressure accumulators 6a and 6b are provided downstream of the normal closed solenoid valves 4a, 4b and 4c on the front wheels FR and FL and the rear wheels RR and RL. In the mode, the oil discharged from the brakes 9a, 9b, 9c, and 9d is temporarily stored. In addition, first and second high pressure accumulators 8a and 8b are disposed behind the first and second low pressure accumulators 6a and 6b, and a pair of first and second pumps 7a and 7b are disposed therebetween. 7b) is configured to pressurize the low pressure oil in the first and second low pressure accumulators 6a and 6b to pump the first and second high pressure accumulators 8a and 8b. Reference numeral 7 denotes a motor for driving the first and second pumps 7a and 7b.

In the conventional anti-lock brake system configured as described above, when the driver presses the brake pedal 1 while driving, the back force is generated by the pressure difference in the power supply device 1a, and the master cylinder 3 receives the amplified force. To form hydraulic pressure. The hydraulic pressure is transmitted to the respective brakes 9a, 9b, 9c, and 9d provided on the front wheels FR and FL and the rear wheels RR and RL through the normally open solenoid valves 5a, 5b, and 5c to perform a braking action. do.

On the other hand, when excessive braking pressure is transmitted than the road condition, a kind of slip phenomenon occurs that the tire of the vehicle stops rotating and slips, and this phenomenon is detected by the wheel sensor 2a mounted on the wheel of the vehicle and the antilock brake system is detected. To the electrical control device (2). Accordingly, the electric control device 2 operates to open the normal closed solenoid valves 4a, 4b, and 4c to remove the oil in the brakes 9a, 9b, 9c, and 9d, thereby lowering the braking pressure. The oil discharged through the normal closed solenoid valves 4a, 4b, and 4c is moved to the first and second low pressure accumulators 6a and 6b, and is temporarily stored. As the motor 7 is driven, the oil is discharged. The pressure rises again through the second pumps 7a and 7b to the first and second high pressure accumulators 8a and 8b and the master cylinder 3 or the normally open solenoid valves 5a, 5b and 5c. It will cycle.

In the conventional anti-lock brake system, oil coming out of each of the brakes 9a, 9b, 9c, and 9d during the braking pressure decompression process is temporarily stored in the first and second low pressure accumulators 6a and 6b. The pump is discharged again by driving the second pumps 7a and 7b to go to the master cylinder 3, and then exits through the first and second high pressure accumulators 8a and 8b in the process of entering the master cylinder 3. do. At this time, the first and second high pressure accumulators 8a and 8b are driven with the pumps 7a and 7b having a 180 degree phase difference, so that the oil escapes from the front wheels FR and FL brakes 9a and 9b. When the first high pressure accumulator 8a is full, the second high pressure accumulator 8b in which the oil exiting from the rear wheels RR, RL side brakes 9c, 9d is stored becomes less cold. For this reason, noise is generated due to the flow rate difference discharged to the master cylinder 3 or the brakes 9a, 9b, 9c, and 9d.

That is, since the oil pumping action is alternately performed between the first high pressure accumulator 8a and the second high pressure accumulator 8b, the amount of oil temporarily stored therein alternately occurs. As a result, a difference occurs between the oil flow rate discharged from the first high pressure accumulator 8a to the master cylinder 3 and the oil flow rate discharged from the second high pressure accumulator 8b, thereby causing a braking action of the antilock brake system. Significant noise is generated during the process. In addition, the first and second low pressure accumulators 6a and 6b, the first and second pumps 7a and 7b, and the first and second high pressure accumulators 8a and 8b are all modulators. It is provided in the body (not shown) of the not shown, there is a limit to compact the modulator (not shown) because the high-pressure accumulator (8a, 8b) is composed of two respectively.

The present invention is to solve this problem, an object of the present invention is to connect the discharge line side hydraulic line of the first pump and the second pump with the inlet side hydraulic line of the high pressure accumulator and the discharge port side hydraulic line of the high pressure accumulator Is connected to the master cylinder and the front and rear brake hydraulic lines to reduce the pulsation of pressure discharged from the first pump and the second pump through a single high-pressure accumulator to provide an anti-lock brake system that reduces the overall operating noise. will be.

1 is a schematic diagram of a conventional anti-lock brake system.

2 is a schematic diagram of an antilock brake system according to the present invention.

* Description of the symbols for the main parts of the drawings *

10. Brake pedal 20. Electronic control device 30. Master cylinder

40. Normally closed solenoid valve 50. Normally open solenoid valve

60.61 Low pressure accumulator 70 Motor 71,72 Pump

80. High pressure accumulator 80a. Inlet side hydraulic line 80b. Outlet side hydraulic line

The present invention for achieving the above object, the master cylinder for forming the braking hydraulic pressure in accordance with the operation of the brake pedal, respectively provided on the front and rear wheels of the vehicle brakes to receive the braking hydraulic pressure to exert a braking force, the inlet and outlet of the brake Normally open solenoid valves and normal closed solenoid valves provided on each side to control the flow of hydraulic pressure, the first low pressure accumulator and the second low pressure for temporarily storing oil discharged from the front and rear wheel brakes during a decompression braking action. The accumulator, the high pressure accumulator which pressurizes the oil stored in the 1st low pressure accumulator and the 2nd low pressure accumulator by operation of a 1st, 2nd pump, and discharges it to a brake side and a master cylinder as needed again. In the anti-lock brake system with

The high pressure accumulator is connected to the discharge port side hydraulic lines of the first pump and the second pump and has an inlet side hydraulic line into which the hydraulic pressure flows, and a discharge side side hydraulic line connected to the master cylinder and the brake side hydraulic line. It is characterized by.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. 2 is a schematic diagram of an antilock brake system according to the present invention.

The anti-lock brake system according to the present invention, as shown therein, brakes 90, 91, 92, 93 provided on the front wheels FR, FL and the rear wheels RR, RL and brake pedals 10 provided on one side of the driver's seat, respectively. ), The master cylinder 30 is provided with the boosting device 11 and the oil storage tank 31 so that the braking hydraulic pressure is generated by the operation of the pedal 10. Solenoid valves are installed at the inlet and outlet sides of the brakes 90, 91, 92, and 93, respectively, to control the flow of hydraulic pressure, which is normally open solenoid valves 50, 51, 52, and outlets installed at the inlet side. Normally closed solenoid valves (40, 41, 42) provided in the.

The first low pressure accumulator is connected to a hydraulic line connecting the discharge port side of the normal closed solenoid valves 40, 41, and 42 on the front wheel FR, FL side and the rear wheel RR, RL side to the master cylinder 30. 60), the second accumulator 61 and the high pressure accumulator 80, which is a kind of damping chamber for reducing pressure pulsation, are provided. Therefore, the oil discharged from the front wheel (FR, FL) and the rear wheel (RR, RL) side brakes (90, 91, 92, 93) during the opening operation of the normal closed solenoid valves (40, 41, 42) according to the decompression braking This is temporarily saved separately. In addition, the first and second pumps 71 and 72 are operated by driving the motor 70 provided between each of the low pressure accumulators 60 and 61 and the high pressure accumulator 80 to thereby operate the first low pressure accumulator. The oil stored in 60 is pressurized and discharged and stored in the high pressure accumulator 80, and the oil stored in the second low pressure accumulator 61 is also pressurized and discharged and stored in the high pressure accumulator 80. The oil stored in the high pressure accumulator 80 is transferred to the brake (90.91.92.93) side or returned to the master cylinder 30 along the hydraulic line. The high pressure accumulator 80 is composed of only one first pump. The pulsation of the pressure discharged from the high pressure from the 71 and the second pump 72 is reduced. To this end, the inlet side hydraulic line 80a of the high pressure accumulator 80 is connected to the outlet side hydraulic line of the first pump 71 and the second pump 72, and the outlet side hydraulic line 80b thereof is a master. The first pump 71 and the second pump 72 are connected to the hydraulic lines of the cylinders 30 and the brakes 90, 91, 92 and 93 of the front and rear wheels FR, FL, RR and RL. The oil to be pumped is stored in a temporary flow into the high pressure accumulator 80, and is supplied to the brakes 90, 91, 92, 93 and the master cylinder 30 as necessary.

The high pressure accumulator 80 is formed to have a larger diameter than the conventional one. In the conventional system, the oil stored in the first and second low pressure accumulators 6a and 6b by the first and second pumps 7a and 7b is supplied to the first and second high pressure accumulators 8a and 8b. Returning to the master cylinder 3, the volumes of the first and second high pressure accumulators 8a and 8b are designed equal to each other. The first and second high pressure accumulators 8a and 8b are driven by their elasticity of the modulator body (not shown) when the first and second pumps 7a and 7b are driven to discharge oil. . Therefore, the larger the volume of the first and second high pressure accumulators 8a and 8b is, the better. Therefore, in the anti-lock brake system according to the present invention, one high-pressure accumulator 80 is configured to complete its function while reducing the overall system size.

To this end, the diameter of the high-pressure accumulator 80 is about 1.4 times larger than the diameter of the conventional one, the background is as follows. First, the conventional first and second high pressure air gun volume of the accumulator (8a, 8b) is _{^{2 * (лd 2/4)}} * l. In this case, d represents the diameters of the first and second high pressure accumulators 8a and 8b, and l is the depth thereof. And the total volume of the high-pressure accumulator 80 according to the present invention should be the same as the conventional one, the volume is лD ² * l. At this time, D represents the diameter of the high-pressure accumulator 80 according to the present invention, l is the depth thereof. Thus _{^{2 * (лd 2/4)}} * l = лD 2 * l and is established as equation, D is 1.4d. As a result, if the diameter of the high-pressure accumulator 80 according to the present invention is 1.4 times or more than the conventional one, there is no problem in system operation even if only one.

On the other hand, the driving of the motor 70 and all opening and closing operations of each solenoid valve are performed by the electric control device 20, which is the wheel sensor 21 installed on each front wheel FR, FL and rear wheels RR, RL. Controls the braking pressure and the rising speed based on the signal input through.

Next, a general braking operation of the vehicle antilock brake system according to the present invention configured as described above will be described.

The driver steps on the brake pedal 10 to decelerate the vehicle or maintain the stopped state while driving or stopping the vehicle. Accordingly, the boosting power amplified than the input from the boosting device 11 is formed, and thus, the braking hydraulic pressure of a considerable pressure is generated in the master cylinder 30. The braking hydraulic pressure is transmitted to each of the brakes 90, 91, 92, and 93 provided on the front wheels FR, FL and the rear wheels RR, RL through the normally open solenoid valves 50, 51, and 52. Is done. When the driver releases the brake pedal 10 little by little or completely, the oil pressure in each brake 90, 91, 92, 93 is returned to the master cylinder through the normal-open solenoid valves 50, 51, 52. The braking force is reduced or the braking action is completely released.

On the other hand, brakes (90, 91, 92, 93) generated by the braking pressure when the driver increases the braking pressure than the road surface state or changes the road surface condition while controlling the braking force increase / hold state for the purpose of deceleration or stopping while driving the vehicle. When the frictional force of Ess is greater than the braking force generated from the tire or the road surface of the vehicle, the wheels of the vehicle slide on the road surface. Accordingly, the vehicle loses steering power and increases the braking distance, and also requires ABS control because the vehicle rotates. The ABS is controlled in three modes, such as boost, depressurization, and maintenance, and each control state is not controlled to the same state on all four wheels of the vehicle, but is separately controlled according to the road condition and the ABS control state. The modes are mixed and controlled.

First, the pressure reduction operation of the vehicle anti-lock brake system according to the present invention will be described. If the braking pressure in the brakes 90, 91, 92, 93 is greater than the road surface condition, the braking pressure should be lowered to the appropriate pressure. Accordingly, in the electric control device 20, the normal closed solenoid valves 40, 41, 42 are opened to operate, so that the brakes 90, 91, 92, on the front wheel FR, FL and rear wheels RR, RL, The oil discharged from the 93 is temporarily stored in the first low pressure accumulator 60 and the second low pressure accumulator 61. At this time, the opening operation of each normal closed solenoid valve 40, 41, 42 is performed simultaneously or separately. Through this process, the pressures of the brakes 90, 91, 92, and 93 mounted on the front wheels FR and FL and the rear wheels RR and RL are lowered, thereby preventing the sliding of the road surface.

And the pressure-increasing operation of the vehicle anti-lock brake system according to the present invention is as follows. If the ABS depressurization state lasts for a long time or the vehicle progresses and moves to a place where the friction coefficient of the road is high, the vehicle tires and the road surface can be braked by the braking pressure in the brakes 90, 91, 92, and 93. The friction force that can be generated in the car increases, which reduces the braking efficiency of the vehicle. In this case, the electric controller 20 determines the situation based on the signals input from each wheel sensor 21 and drives the motor 70 to increase the braking pressure in the brakes 90, 91, 92, and 93. The first and second pumps 71 and 72 are operated. Accordingly, the oil stored in the first and second low pressure accumulators (60, 61) during the ABS pressure reduction operation is pressurized into the high pressure accumulator (80) through the inlet side hydraulic line (80a), and continues to discharge It is transmitted to the brakes (90, 91, 92, 93) through the side hydraulic line (80b) and the normally open solenoid valves (50, 51, 52) opened, thereby increasing the braking hydraulic pressure.

In the ABS control, the pressure in the brakes 90, 91, 92 and 93 reaches the optimum pressure for generating the optimum braking force, or the pressure is kept constant to prevent the resonance of the vehicle derived from the ABS control. An operating condition is required, the pressure holding operation of the anti-lock brake system according to the present invention is as follows. The pressure holding state to prevent pressure change in the brakes 90, 91, 92, and 93 mounted on the front wheels FR, FL and rear wheels RR, RL of the vehicle is one of the normal open solenoid valves 50, 51, 52. Closing operation of the normally open solenoid valves (50, 51, 52) of the brake (90, 91, 92, 93) to maintain the pressure to block the transmission of the hydraulic pressure, oil pressure of the high-pressure accumulator (80) Is transmitted to the master cylinder 30 side.

Therefore, the oil stored in the first and second low pressure accumulators 60 and 61 during the braking operation of the anti-lock brake system according to the present invention is pressurized and introduced into the high pressure accumulator 80. If necessary, it is supplied back to the master cylinder 30 and the brakes 90, 91, 92, and 93, and is supplied through the discharge line side hydraulic line 80b of one high-pressure accumulator 80. This does not occur. In addition, since the body of the modulator (not shown) includes only one high-pressure accumulator 80, the overall size can be reduced.

As described in detail above, the vehicle anti-lock brake system according to the present invention connects the discharge line side hydraulic lines of the first pump and the second pump with the inlet side hydraulic line of the high pressure accumulator, and the outlet side hydraulic pressure of the high pressure accumulator. By connecting the line with the hydraulic lines of the master cylinder and the front and rear brakes, the pulsation of the pressure discharged from the first pump and the second pump is reduced by one high-pressure accumulator. Accordingly, since only one high-pressure accumulator is installed on the body of the modulator, the number of parts can be reduced, and the body size of the modulator can be reduced to make it compact.

Claims (1)

The brake is provided on the master cylinder 30 to form the braking hydraulic pressure according to the operation of the brake pedal 10, the front wheels FR and FL and the rear wheels RR and RL of the vehicle, respectively. 90, 91, 92, 93, the normally open solenoid valve (50, 51, 52) and the normal closed type provided on the inlet side and the outlet side of the brake (90, 91, 92, 93) respectively to control the flow of hydraulic pressure The solenoid valves (40, 41, 42) temporarily store the oil discharged from the brakes (90,91) on the front wheel (FR, FL) side and the brakes (92, 93) on the rear wheel (RR, RL) side during the decompression braking operation. The first low pressure accumulator 60 and the second low pressure accumulator 60 are operated by operating the first low pressure accumulator 60, the second low pressure accumulator 61, and the first and second pumps 71 and 72. The oil stored in the accumulator 61 is pressurized and introduced into the high pressure accumulator for discharging the oil to the brake 90, 91, 92, 93 and the master cylinder 30 as necessary. In the anti-lock brake system with a foundation (80) The high pressure accumulator 80 is connected to a discharge line side hydraulic line of the first pump 71 and the second pump 72 to the inlet side hydraulic line 80a and the master cylinder 30 into which the hydraulic pressure flows. And a discharge port side hydraulic line (80b) connected to the brake (90,91,92,93) side hydraulic line to discharge the hydraulic pressure.

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