KR20010092860A - A high pressure accumlator of anti-lock brake system - Google Patents

Abstract

PURPOSE: A high-pressure accumulator of an ABS(Anti-lock Brake system) is provided to efficiently reduce pressure pulsation of pumping oil and noise by modifying the high-pressure accumulator, and to improve reliability and compact a modulator block. CONSTITUTION: A high-pressure accumulator is composed of a damping piston(55) reciprocating axially according to inflow of oil, and an elastic member(56) supporting the damping piston, and a cylindrical damping chamber to reduce pressure pulsation by flowing brake oil according to driving a pump in braking with an ABS. The damping chamber is divided into a first damping chamber(51A) and a second damping chamber(51B). An orifice hole(57) is formed in the damping piston to penetrate first and second damping chambers. Oil flows into the first damping chamber with pushing the damping piston against the elastic member, and into the second damping chamber through clearance between the damping piston and the damping chambers. The pressure pulsation of oil is reduced with restoring force of the damping piston and the elastic member, and eliminated with passing through an orifice(53A). The noise is reduced, and the vibration of the brake is prevented with eliminating the pressure pulsation of oil from the first damping chamber to the orifice.

Description

A high pressure accumlator of anti-lock brake system

The present invention relates to an antilock brake system, and more particularly, to a high pressure accumulator of an antilock brake system provided in a modulator block to reduce pressure pulsation of oil pumped at high pressure when driving a pump.

In general, the vehicle is equipped with hydraulic brakes mounted on the front and rear wheels for the purpose of decelerating or stopping while driving, and a hydraulic power unit and a master cylinder that forms a braking hydraulic pressure and transmits it to the hydraulic brake side. Is formed and it is transmitted to the hydraulic brake to generate a braking force. However, when the driver presses the brake pedal and controls the braking force to increase / hold, if the braking pressure is greater than the road surface state or the frictional force of the hydraulic brake generated by the braking pressure is greater than the braking force generated from the tire or road surface, the tire is A slipping phenomenon occurs.

Anti-lock Brake System is to prevent such slip phenomenon and to obtain strong and stable braking force. It is a number of solenoid valves, accumulators and pumps for controlling the transmission of braking hydraulic pressure to the hydraulic brake side. It is provided.

Referring to FIG. 1, a conventional anti-lock brake system 10 includes a modulator block (not shown) made of aluminum and a plurality of solenoid valves mounted on the modulator block to control braking hydraulic pressure delivered to the hydraulic brake 3. 11A) 11B, a pair of low pressure accumulator 12 and high pressure accumulator 15 for temporarily storing oil, and a motor for forcibly pumping oil temporarily stored in low pressure accumulator 12 ( 13) and pump 14, and an ECU (not shown) for controlling the electrically actuated components.

The solenoid valve is divided into NO type solenoid valve 11A disposed on the upstream side of the hydraulic brake 3 and NC type solenoid valve 11B disposed on the downstream side and controlled by the ECU. The ECU senses the vehicle speed through each wheel sensor (not shown) disposed on the front wheels FR, FL and RR RL, and controls the opening and closing operation of each solenoid valve 11A, 11B. Done.

In addition, the pair of low pressure accumulators 12 are independently provided on the downstream side of the NC type solenoid valve 11B to temporarily store the oil escaping from the hydraulic brake 3 side in the decompression mode, and the pair of high pressure accumulators. 15 is a type of damping chamber, which is arranged to be connected in series with the low pressure accumulator 12, and an orifice 16 is provided at the outlet portion.

In addition, a pair of pumps 14 driven by one motor 13 is disposed between the low pressure accumulator 12 and the high pressure accumulator 15 and pressurizes the oil in the low pressure accumulator 12. To be pumped to the high-pressure accumulator (15) side. The pair of low pressure accumulators 12 and pump 14, the pair of high pressure accumulators 15 and the plurality of solenoid valves 11A and 11B are compactly mounted on the modulator block.

When the brake pedal 1 is stepped on a vehicle equipped with the conventional anti-lock brake system configured as described above, the boosting force is formed in the power supply device 2, whereby the braking hydraulic pressure is generated in the master cylinder 4. This braking hydraulic pressure is transmitted to each hydraulic brake 3 through the NO type solenoid valve 11A to perform a braking action.

On the other hand, when excessive braking pressure is transmitted or road surface is slippery than road condition, slip phenomenon occurs that the vehicle slips. ECU detects slip phenomenon based on the signal input from the wheel sensor mounted on the wheel of the vehicle. If a slip phenomenon is detected, the ECU actuates the NC solenoid valve 11B to open to remove the oil in the hydraulic brake 3 to lower the braking pressure. Subsequently, the oil discharged through the NC solenoid valve 11B is moved to the pair of low pressure accumulators 12 and stored for a while, and the pressure is increased again via the pump 14 as the motor 13 is driven. Guided to a pair of high-pressure accumulator 15, it is supplied back to the master cylinder (4) or NO solenoid valve (11A).

At this time, the pair of high-pressure accumulator 15 is configured to have a chamber in the modulator block made of aluminum, so that oil pumped at high pressure through the pump 14 is temporarily stored to reduce pressure pulsation. In addition, the pressure pulsation of oil discharged by the orifice 16 disposed at the outlet of the high pressure accumulator 15 is further reduced and supplied to the hydraulic line.

However, in the conventional anti-lock brake system, the sudden pressure pulsation generated by the driving of the pump 14 is reduced by the orifice 16 provided on the outlet side of the high pressure accumulator 15, and the orifice 16 simply reduces the opening degree of the flow path. There is a limit to significantly reduce the pressure pulsation by sharply reducing the pressure pulsation of the irregular oil.

Therefore, the pressure pulsation peak of the pressurized oil remains, which acts as a cause of the operation noise of the anti-lock brake system 10, and the pressure pulsation is transmitted to the brake pedal 1 side through the master cylinder 4, thereby causing anxiety to the driver. There is a problem that results.

The present invention is to solve this problem, the main object of the present invention is to improve the high pressure accumulator high pressure control of the anti-lock brake system that can more effectively reduce the pressure pulsation of the oil pumped to high pressure when the pump is driven To provide a curator.

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

2 is a hydraulic system diagram of an anti-lock brake system for a vehicle according to the present invention.

3 is a cross-sectional view of the high-pressure accumulator according to the present invention.

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

50. High pressure accumulator 51A, 51B Damping chamber

52..Inport 53..Outport

54. Plug 55. Damping piston

56. Elastic member 57. Orifice hole

The present invention for achieving this object is; High pressure accumulator of the anti-lock brake system, which is connected to the discharge side of the pump and has a cylindrical damping chamber inside to reduce the pressure pulsation due to the inflow of brake oil pumped according to the pump operation during ABS pressure braking or pressure holding braking. To

And a damping piston for dividing the damping chamber into a first damping chamber and a second damping chamber, the damping piston being arranged to reciprocate in the axial direction as the oil enters, and an elastic member for elastically supporting the damping piston.

In addition, the damping piston is characterized in that the orifice hole for the communication between the first damping chamber and the second damping chamber is drilled.

According to this structure, since the oil pressurized while pushing the elastically supported damping piston flows into the damping chamber, the pressure pulsation of the oil can be reduced more efficiently.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. Briefly, the accompanying drawings, Figure 2 is a hydraulic system of the ABS according to the present invention, Figure 3 is a cross-sectional view taken from the high pressure accumulator according to the present invention.

2, the vehicle anti-lock brake system 30 according to the present invention for controlling the braking hydraulic pressure transmission to the hydraulic brake 23 side installed on the front wheel (FR) (FL) and the rear wheel (RR) (RL). A plurality of solenoid valves 33A, 33B, a pair of low pressure accumulators 34, in which oil from the hydraulic brake 23 side is temporarily stored during the decompression braking operation, and a storage fish during the boost / hold braking operation. A motor 35 and a pair of pumps 40 for pumping oil stored in the cumulator 34 and a pair of high pressure accumulators 50 for reducing pressure pulsation of oil pressurized and discharged by driving the pump 40. Are mounted on the modulator block 31 compactly.

The plurality of solenoid valves are connected to the upstream and downstream sides of the hydraulic brake 23, and are arranged on the upstream side and are normally connected to the NO type solenoid valve 33A and the downstream which are kept open and are normally closed. It is distinguished by the NC type solenoid valve 33B maintained in the state. The opening / closing operation of the solenoid valves 33A and 33B is respectively performed by the ECU 32 which detects the vehicle speed through the wheel sensors 24 disposed on the front wheel FR and the rear wheel RR RL. Controlled and the NC type solenoid valve 33B is opened according to the decompression braking action so that the oil exiting from the hydraulic brake 23 side is temporarily stored in the low pressure accumulator 34.

In addition, the pair of pumps 40 are driven simultaneously while having a phase difference of 180 degrees by one motor 35 to discharge the oil stored in the low pressure accumulator 34 to the pressurized high pressure accumulator 50 side. The oil introduced into the accumulator 50 is transferred to the hydraulic brake 23 side along the hydraulic line again or returned to the master cylinder 22 while the pressure pulsation is reduced.

As shown in FIG. 3, the high-pressure accumulator 50 is configured in a cylindrical shape through boring on the side surface of the modulator block 31. As shown in FIG. The lower portion of the high-pressure accumulator 50 is provided with an inlet 52 through which the oil pressurized by the pump 40 flows in and an outlet 53 through which the oil is discharged. The outlet 53 includes a master cylinder 22. ) And the hydraulic brake 23 side and the hydraulic line is connected to the orifice 53A.

The opening of the high pressure accumulator 50 is sealed through the plug 54, so that the damping chambers 51A and 51B are formed in the high pressure accumulator 50. In addition, the damping chambers 51A and 51B are provided with a damping piston 55 reciprocating in the axial direction as the oil enters and exits, and an elastic member 56 for elastically supporting the damping piston 55. By the damping piston 55, the damping chamber is provided with a first damping chamber 51A in which oil is introduced and the pressure pulsation is actually reduced, and a second damping chamber 51B in which an elastic member 56 made of a coil spring is installed. Compartment.

The damping piston 55 is provided in a cup shape having a cylindrical side surface 55B and a bottom surface 55A having an orifice hole 57 bored to have a predetermined diameter, and the reciprocating motion of the damping piston 55 is It is preferable to comprise so that the inner periphery of damping chamber 51A (51B) and predetermined clearance G may be possible. The elastic modulus of the elastic member 56 is preferably set such that the damping piston 55 directly receiving the oil pressure can reciprocate while having an appropriate stroke.

On the other hand, the damping piston 55 is not limited to being configured in a cup shape, but may be configured in a circular plate shape having a predetermined thickness. In addition, the orifice hole 57 drilled in the damping piston 55 is for communicating the first damping chamber 51A and the second damping chamber 51B, and is provided through the orifice hole 57 during the air removal operation of the ABS. Oil and air in the first damping chamber 51A and the second damping chamber 51B come out, which will be described in detail in the description of the operation.

Next will be described the operation and effect of the high-pressure accumulator 50 according to the present invention configured as described above.

First, the driver steps on the brake pedal 20 to decelerate the vehicle or maintain the stop state. In the case of a normal braking operation, a boosting force amplified than the input from the boosting device 21 is formed, and thus, the master cylinder 22. In this case, a considerable braking hydraulic pressure is generated. This braking hydraulic pressure is transmitted to the hydraulic brake 23 side through the NO type solenoid valve 33A, whereby a braking action of the vehicle is achieved. When the driver releases the brake pedal 20 little by little or completely, the oil pressure in the hydraulic brake 23 is returned to the master cylinder 22 again through the NO-type solenoid valve 33A and the braking force is reduced or the braking action is performed. This is completely released.

The frictional force of the hydraulic brake 23 generated by the brake pressure due to the braking pressure is increased when the driver increases the braking pressure to the road surface state or changes the road surface condition while controlling the braking force to increase / maintain for the purpose of deceleration or stop while driving. If the braking force generated from the tire or the road surface is greater than that, a slip phenomenon occurs that the tire slips on the road surface. As a result of the slip phenomenon, the vehicle loses steering power and increases the braking distance, and the ABS rotates because the vehicle rotates. The ABS is controlled in three modes, such as decompression, boosting, and holding, based on signals input from the wheel sensors 24 disposed in the front wheels FR and FL, respectively. The control state is not controlled to the same state in both the front wheel FR and the rear wheel RR RL, but is controlled separately according to the friction condition, that is, the three modes are mixed.

First, the braking pressure decompression operation of the vehicle vehicle antilock brake system 30 will be described. If the braking pressure in the hydraulic brake 23 is greater than the road surface condition while braking is being performed, the braking pressure should be lowered to an appropriate pressure. Accordingly, the ECU 32 opens and operates the NC type solenoid valve 33B, so that the oil exiting from the hydraulic brake 23 is temporarily stored in the low pressure accumulator 34. At this time, the opening operation of each NC solenoid valve 33B is performed simultaneously or separately. Through this process, the braking pressure in the hydraulic brake 23 mounted on the front wheel FR and the rear wheel RR RL side is lowered, thereby preventing the phenomenon of sliding on the road surface.

The braking pressure boosting operation of the antilock brake system 30 is as follows. If the ABS depressurization state lasts for a long time during ABS control or the vehicle proceeds to a place where the friction coefficient of the road surface is high, the friction force that can be generated on the tire and the road surface may be higher than that of the brake pressure in the hydraulic brake 23. The increase in the braking efficiency of the vehicle occurs.

In this case, the driving pump 40 operates the motor 35 to increase the braking pressure in the hydraulic brake 23 based on the signals input from the wheel sensors 24. . Accordingly, the brake oil temporarily stored in the low pressure accumulator 34 is pressurized through the pump 40, and the high pressure accumulator 50 having the damping chambers 51A and 51B formed through the inlet 52. ), The pressure pulsation of the oil is primarily reduced. Subsequently, the pressurized oil having reduced pressure pulsation is discharged to the hydraulic line through the outlet 53, and the braking hydraulic pressure is increased by being delivered to the hydraulic brake 23 through the open-type NO solenoid valve 33A. At this time, since the pressurized oil discharged to the hydraulic line passes through the orifice 53A disposed in the outlet 53, the pressure pulsation of the oil is secondarily reduced, so that the braking action is more stably performed.

Meanwhile, in order to prevent the braking pressure in the hydraulic brake 23 from generating the optimum braking force in the ABS control or to prevent resonance of the vehicle derived during the ABS control, the braking pressure maintaining operation maintains the braking pressure in a constant state. This is necessary. That is, the pressure holding operation eliminates the pressure change in the hydraulic brake 23 mounted on the front wheel FR and the rear wheel RR of the vehicle, which is the hydraulic brake 23 to maintain the braking pressure. The NO-type solenoid valve 33A on the side is closed to block hydraulic pressure from being transmitted. Accordingly, the pressurized oil discharged from the high pressure accumulator 50 is transferred to the master cylinder 22 side, whereby the braking pressure maintenance operation is performed.

On the other hand, the oil stored in the low-pressure accumulator 34 during the braking pressure boosting operation and the pressure holding operation is pressurized by the operation of a pair of pump 40 is supplied to the high-pressure accumulator 50, and the orifice 53A ) Is supplied to the NO type solenoid valve 33A or the master cylinder 22 side. At this time, since the pair of pumps 40 operate with a constant phase difference, the oil flowing into the high-pressure accumulator 50 generates a constant peak of pressure pulsation, which is a high pressure in which the damping piston 55 is built. It is completely reduced through the accumulator 50 and the orifice 53A.

That is, the pressurized oil introduced through the inlet 52 is introduced into the first damping chamber 51A while pressing the damping piston 55 by defeating the force of the elastic member 56, and part of the damping piston 55 and the damping piston 55. By flowing into the second damping chamber 51B through the clearance G with the chambers 51A and 51B, the pressure pulsation of the oil is significantly reduced by the elastic restoring force of the damping piston 55 and the elastic member 56. Subsequently, the oil discharged through the outlet 53 passes completely through the orifice 53A, and the pressure pulsation is completely removed and transferred to the hydraulic brake 23 or the master cylinder 22 side.

Accordingly, the pressure pulsation of the periodic oil generated by driving the pump 40 in the process of flowing the pressurized oil into the first damping chamber 51A while pressing the damping piston 55 and then discharging it through the orifice 53A. Since this is completely removed, the operation noise of the antilock brake system is reduced as well as the shaking phenomenon of the brake pedal 20 is prevented.

In addition, when the brake oil is first injected or replaced with the hydraulic circuit of the anti-lock brake system mounted on the vehicle, an operation of removing air in the hydraulic circuit is performed. For this purpose, an oil storage tank associated with the master cylinder 22 is performed. A vacuum generator (not shown) is connected to 22A (see FIG. 2) to apply a vacuum. Accordingly, the oil and air in the hydraulic line connecting the low pressure accumulator 34 and the high pressure accumulator 50, the hydraulic brake 23 and the respective components come out through the oil storage tank 22A. The oil and air in the high pressure accumulator 50 partitioned into the first damping chamber 51A and the second damping chamber 51B through the damping piston 55 are perforated on the bottom surface 55A of the damping piston 55. It is easily discharged through the orifice hole 57.

As described in detail above, according to the high-pressure accumulator of the anti-lock brake system according to the present invention, the damping chamber is divided into a first damping chamber and a second damping chamber, and at the same time, the damping piston is elastically supported by an elastic member. As a result, the pressure pulsation of the oil generated when the pump is driven more efficiently is reduced, thereby reducing the operating noise of the anti-lock brake system and improving reliability. In addition, since the damping piston and the elastic member can effectively reduce the pressure pulsation of the oil while reducing the contents of the high-pressure accumulator, there is an advantage that the size of the modulator block can be more compactly configured.

Claims (2)

High pressure accumulator of the anti-lock brake system, which is connected to the discharge side of the pump and has a cylindrical damping chamber inside to reduce the pressure pulsation due to the flow of brake oil pumped by the pump operation during ABS pressure braking or pressure holding braking. In the radar, The damping piston is divided into a first damping chamber 51A and a second damping chamber 51B, and the damping piston 55 and the damping piston 55 are arranged to reciprocate in the axial direction as the oil enters and exits. High-pressure accumulator of the anti-lock brake system, characterized in that it comprises an elastic member 56 for elastically supporting. The method of claim 1, The damping piston (55) is a high-pressure accumulator of the anti-lock brake system, characterized in that the orifice hole (57) for the communication between the first damping chamber (51A) and the second damping chamber (51B) is drilled.