KR100721375B1 - Pump of electronic control brake system - Google Patents

Abstract

The present invention relates to a pump of an electronically controlled brake system, and its object is to improve its discharge performance by increasing the compression ratio as the volume of the pressure chamber formed between the piston and the outlet valve is reduced.

To this end, according to the pump of the electronically controlled brake system according to the present invention, a pressure chamber 43 for pressurizing oil is formed between the front end of the piston 41 and the outlet valve 44, which is disposed at the front end of the piston 41. Since the volume reducing member 46 is provided inside the retainer 42c, the volume of the pressurizing chamber 43 is reduced, and as the volume in the pressurizing chamber 43 decreases, the compression ratio is increased to improve the efficiency of the pump. It works.

In addition, although the opening / closing member 42a is restricted from moving in the axial direction by a predetermined distance through the stepped shape of the retainer 42c, in the present invention, the opening and closing member 42a is reduced in volume in the axial direction. The member 46 is restricted.

Therefore, since the step 42 is not required for the retainer 42a, the shape thereof can be simplified, and there is an effect of making it easy to manufacture.

Description

Pump of electronic control brake system

1 is a cross-sectional view showing a pump applied to a conventional electronically controlled brake system.

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

3 is a cross-sectional view showing the internal structure of the pump according to the present invention.

* Explanation of symbols for main parts of drawings *

31: Modulator block 31a: Bore

40L, 40R: Pump 41: Piston

42: inlet valve 42a: opening and closing member

42c: Retainer 44: Outlet Valve

       46: volume reduction member

The present invention relates to an electronically controlled brake system for a vehicle, and more particularly, to a pump of an electronically controlled brake system for forcibly pumping low pressure accumulator side oil to the high pressure accumulator side.

In general, the electronically controlled brake system effectively prevents the slip of the vehicle and obtains a strong and stable braking force.Anti-lock brake system (ABS) to prevent the wheel from slipping during braking and Brake Traction Control System (BTCS) which prevents slippage of driving wheel during sudden start or acceleration, and anti-lock brake system and traction control are combined to control brake hydraulic pressure to keep the vehicle stable. A posture control system (VDC) and the like are disclosed.

The electronically controlled brake system includes a plurality of solenoid valves for controlling braking hydraulic pressure delivered to a hydraulic brake side mounted on a wheel of a vehicle, a pair of low pressure accumulators and high pressure accumulators for temporarily storing oil, and oil stored in the low pressure accumulator. It includes a motor and pump for forced pumping, and an ECU that controls solenoid valves and motor operation. These components are embedded in a modulator block made of aluminum.

Accordingly, the low pressure accumulator side oil is pressurized by the driving of the pump and pumped to the high pressure accumulator, which is transferred to the hydraulic brake or master cylinder assembly side. Such a pump is driven by a motor, and FIG. 1 shows the internal structure of a conventional pump applied to an electronically controlled brake system.

Referring to FIG. 1, a conventional pump 10 is installed in a bore 5 formed in a modulator block 1 to reciprocate by an eccentric spindle 2a of a motor 2, and a suction flow path 6a is formed therein. Opening of the piston 6, the inlet valve 7 for opening and closing the outlet side of the suction flow path 6a according to the position of the piston 6, and the opening of the bore 5 so as to operate opposite to the inlet valve 7 An outlet valve 3 provided at the end and forming a pressurizing chamber 8 between the piston 6 and a return spring disposed in the pressurizing chamber 8 to elastically support the piston 6 in the bottom dead center direction ( 4) Equipped.

The inlet valve 7 is provided at the distal end of the piston 6 facing the outlet valve 3 to open and close the opening and closing member 7a for opening and closing the outlet side of the suction passage 6a, and the opening and closing member 7a. An elastic member 7b for elastically supporting and a retainer 7c to which the elastic member 7b is fixed are provided.

 The retainer 7c has a stepped shape to restrict the opening and closing member 7a from moving in the axial direction more than a predetermined time.

The modulator block 1 includes a suction port 1a for connecting the inlet side 6a of the piston 6 to a low pressure accumulator (not shown), an inlet side of the high pressure accumulator (not shown) and an outlet valve ( The discharge port 1b for linking the outlet side of 3) is machined.

In the conventional pump 10 configured as described above, the piston 6 linearly reciprocates as the eccentric spindle 2a of the motor 2 rotates, and the inlet valve 7 is opposed to each other by a pressure change in the bore 5. And the outlet valve 3 open and close, the oil is pressurized and pumped to the high pressure accumulator side.

That is, when the piston 6 moves to the bottom dead center, the pressure in the pressure chamber 8 drops, whereby the inlet valve 7 is opened and the outlet valve 3 is closed, so that the oil on the low pressure accumulator side is sucked into the suction port ( It is sucked into the pressure chamber 8 between the piston 6 and the outlet valve 3 through 1a), the suction flow path 6a, and the inlet valve 7.

On the other hand, when the piston 6 moves to the top dead center, the pressure in the pressure chamber 8 rises, thereby closing the inlet valve 7 and opening the outlet valve 3, whereby oil discharges the discharge port 1b. Pumped through the accumulator side.

Such a pump increases the compression ratio, thereby improving its efficiency. The compression ratio can be obtained from the following equation.

       Compression ratio =           Piston sliding volume  Pump pressurized volume + piston sliding volume

Based on the above equation, as the volume of the pressure chamber 8 decreases, the compression ratio is relatively increased.

However, in the conventional pump structure, it is not easy to configure the front end of the piston 6 close to the outlet valve 3 by the inlet valve 7 having the opening / closing member 7a at the front end of the piston 6. The pressure chamber 8 formed between the 6 and the outlet valve 3 has a considerable volume, which causes a problem that the overall efficiency of the pump is lowered.

The present invention is to solve this problem, an object of the present invention to improve the compression ratio by improving the pressure chamber structure to provide a pump of an electronically controlled brake system that can improve the discharge performance of the pump.

The present invention for achieving this object is;

A piston provided with a suction flow path for linearly reciprocating motion in the bore formed in the modulator block and sucking the oil on the low pressure accumulator side, and a pressure chamber installed in the bore to form a pressure chamber and reciprocating the piston In the pump of the electronically controlled brake system having an outlet valve which is opened and closed by the inlet valve, and an inlet valve which is opened and closed opposite to the outlet valve and guides the oil flowing into the suction flow path to the outlet valve.

The inlet valve includes an opening and closing member disposed at the tip of the piston to selectively open and close the suction passage, and a retainer in which an oil passage is formed and guides the axial movement of the opening and closing member.

Inside the retainer is characterized in that a volume reducing member is provided to reduce the volume of the pressure chamber.

In addition, the retainer has a hollow cylindrical shape and has a constant radius from a portion where the opening and closing member is disposed to an end portion of the outlet valve side.

In addition, the opening and closing member is characterized in that it has a spherical shape.

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 showing an electronically controlled brake system according to the present invention, Figure 3 shows a pump structure according to the present invention.

2, the electronically controlled brake system 30 for a vehicle according to the present invention includes a plurality of solenoid valves 33A and 33B for controlling the braking hydraulic pressure transmission to the hydraulic brake 23 side installed on the front wheel and the rear wheel, The low pressure accumulator 34, which temporarily stores oil escaping from the hydraulic brake 23 side during the decompression braking operation, the motor 35 for pumping oil stored in the storage accumulator 34 during the boost / maintenance braking operation, and A pair of pumps 40L and 40R and a high pressure accumulator 36 having an orifice 36a at the outlet side in order to reduce the pressure pulsation of oil pressurized and discharged by driving the pumps 40L and 40R are provided. These components are compactly embedded in a rectangular parallelepiped modulator block 31 made of aluminum.

The plurality of solenoid valves 33A and 33B are connected to the upstream side of the hydraulic brake 23 and are normally connected to the NO type solenoid valve 33A that is kept open and the downstream side of the hydraulic brake 23. It is distinguished by the NC type solenoid valve 33B which is normally kept closed. The opening and closing operations of the solenoid valves 33A and 33B are respectively controlled by the ECU 32 which detects the vehicle speed through the wheel sensors 24 disposed on the front wheels and the rear wheels. In addition, the NC type solenoid valve 33B is opened in response to the depressurizing braking action, and the oil discharged from the hydraulic brake 23 side is temporarily stored in the low pressure accumulator 34.

The pair of pumps 40L and 40R are driven with a certain phase difference by the motor 35, and the oil stored in the low pressure accumulator 34 is pressurized by driving the pumps 40L and 40R. 36 is supplied to the side and continues to be returned to the hydraulic brake 23 or the master cylinder 22 along the hydraulic line while reducing the pressure pulsation in the high-pressure accumulator 36.

On the other hand, such a pump 40L (40R) has an improved structure to further improve the efficiency, the detailed structure thereof will be described with reference to Figure 3 (pair of pump 40L, 40R). Since the symmetrical spindle is symmetrically with respect to the eccentric spindle of the motor 35, only one pump is enlarged in FIG.

First, a motor 35 is provided on the side of the modulator block 31 so that the spindle 35a protrudes to drive the pumps 40L and 40R. The tip of the spindle 35a of the motor 35 is composed of an eccentric shaft 35b, which is arranged to be in contact with the piston 41 of each pump 40L or 40R, thereby providing a pair of pumps 40L and 40R. ) Is driven with a phase difference of 180 degrees.

In addition, in order to install the pumps 40L and 40R, the modulator block 31 communicates the bore 31a of which both ends were opened transversely, and this bore 31a and the low pressure accumulator 34 side. The suction port 31b and the discharge port 31c for communicating the bore 31a and the high-pressure accumulator 36 side are processed.

The pumps 40L and 40R are slidably installed left and right in the bore 31a and have a piston 41 formed therein with an inlet flow passage 41a in the axial direction therein, and are provided at the end of the piston 41 so as to be provided with a suction passage ( The inlet valve 42 for opening and closing 41a and the open end of the bore 31a are combined to form a pressurizing chamber 43 between the piston 41 and the outlet valve to prevent backflow of oil. 44).

The outlet valve 44 operates opposite to the inlet valve 42 according to the position of the piston 41 to open and close the discharge flow path 44f, and the valve seat 44a having the orifice 44b and the orifice 44b. An opening / closing member 44c disposed in contact with the opening, an elastic member 44d for elastically supporting the opening / closing member 44c, and the elastic member 44d and the opening / closing member 44c are built-in, and the discharge port 31c It consists of the valve housing 44e in which the discharge flow path 44f was formed so that it may be linked.

In addition, a return spring 45 supporting the piston 41 in the bottom dead center direction (arrow B) is provided between the tip of the piston 41 and the outlet valve 44, that is, in the pressure chamber 43.

And the inlet valve 42 is arranged on the outlet side of the suction flow path (41a) of the piston 41, the opening and closing member 42a having a spherical shape, the elastic member 42b for elastically supporting the opening and closing member 42a, The elastic member 42b and the opening / closing member 42a are built-in and have a retainer 42c having an oil passage 42d through which oil can pass.

The retainer 42c has a hollow cylindrical shape and has a constant radius from a portion where the opening / closing member 42a is disposed to an end portion of the outlet valve 44 side, and an end portion of the retainer 42 at the outlet valve 44 side. Inside the volume reducing member 46 is formed of a material such as plastic to reduce the volume of the pressure chamber 43 is provided.

In addition, the volume reduction member 46 serves to limit the opening and closing member 42a from moving toward the outlet valve 44 by a predetermined pressure in addition to reducing the volume of the pressure chamber 43. do.                     

Next will be described the operation and effect of the electronically controlled brake system according to the present invention configured as described above.

When a vehicle slip occurs, the braking hydraulic pressure is controlled in three modes, such as decompression, boosting and holding, based on signals input from the wheel sensors 24 on the front and rear wheels. At this time, each control state is not controlled to the same state in both the front wheel and the rear wheel, but controlled separately, that is, three modes are mixed according to the friction conditions, first, the braking force decompression operation will be described.

First, the hydraulic brake 23 is applied in a state where the braking force is exerted by the braking hydraulic pressure formed by the brake pedal 20 (see FIG. 2) and the hydraulic power unit 21 (see FIG. 2) and the master cylinder assembly 22 (see FIG. 2). If the braking pressure in) is greater than the road surface condition, it should be reduced to the proper pressure. Therefore, the ECU 32 opens and operates the NC type solenoid valve 33B, which causes some oil to escape from the hydraulic brake 23 and is temporarily stored in the low pressure accumulator 34. Through this process, the braking pressure in the hydraulic brake is lowered to prevent the sliding phenomenon on the road surface.

The following describes the braking force boosting operation of the electronically controlled brake system. If the decompression state lasts for a long time during the control of the electronically controlled brake system, the vehicle braking efficiency decreases. In this case, the ECU 32 uses a pair of pumps through the motor 35 to increase the braking pressure in the hydraulic brake 23. Activate 40L) (40R).

Therefore, the oil stored in the low pressure accumulator 34 is pressurized through the pumps 40L and 40R and transferred to the high pressure accumulator 36 side. That is, when the piston 41 moves to the bottom dead center (in the direction of arrow B), oil flows into the pressure chamber 43 through the suction flow path 41a and the inlet valve 42, and the piston 41 moves to the top dead center. When the lower surface (arrow A direction) oil is pressurized in the pressure chamber 43, the outlet valve 44 is opened, and is continuously transmitted to the high pressure accumulator 36 through the discharge passage 44f and the discharge port 31c, and the high pressure accumulator At (36) the oil pressure pulsation is reduced.

The pressurized oil which is continuously reduced in pressure pulsation is delivered to the hydraulic brake 23 side through the open-type NO solenoid valve 33A, whereby the braking hydraulic pressure is increased. At this time, since the pressurized oil discharged to the hydraulic line passes through the orifice 36a of the high pressure accumulator 36, the pressure pulsation of the oil is reduced again.

In addition, in order to reach a state in which the braking pressure generates an optimum braking force in the electronically controlled brake system control or to prevent resonance of the vehicle, a pressure holding operation for maintaining the braking pressure in a constant state is required. That is, the pressure holding operation prevents the pressure change in the hydraulic brake 23, and closes the NO type solenoid valve 33A on the hydraulic brake 23 side to maintain the braking pressure, thereby preventing the hydraulic pressure from being transmitted. . Accordingly, the pressurized oil discharged from the high pressure accumulator 36 is transferred to the master cylinder 22 side, whereby the pressure holding operation is performed.

Such boosting braking is to supply oil to the hydraulic brake 23 by driving the pumps 40L and 40R, and the pump 40L and 40R driving according to the present invention will be described in detail as follows.

That is, when the piston 41 slides to the top dead center as the eccentric spindle 35a of the motor 35 rotates (arrow A direction), the oil pressure in the pressure chamber 43 rises, thereby increasing the inlet valve ( 42 is closed and the outlet valve 44 is opened, so that oil is discharged to the high pressure accumulator 36 through the discharge passage 44f and the discharge port 31c.

On the other hand, when the piston 41 slides to the bottom dead center by the reaction force of the return spring 46 (arrow B direction), the pressurizing chamber 43 is brought into a low pressure state, whereby the inlet valve 42 is opened. Outlet valve 45 is closed. Accordingly, the oil on the low pressure accumulator 34 side is sucked into the pressure chamber 43 through the suction port 31b, the suction flow path 41a, and the inlet valve 42.

This suction / discharge stroke is performed once per rotation of the spindle 35a of the motor 35, and the pressure reducing chamber 46 is provided inside the retainer 42c provided at the tip of the piston 41 to pressurize the chamber. 43) will be reduced in volume. Therefore, as the volume in the pressure chamber 43 decreases, the compression ratio is relatively increased, thereby improving the efficiency of the pump.

In addition, the volume reduction member 46 also serves to limit the movement of the opening and closing member 42a over a predetermined distance in the axial direction.

As described in detail above, according to the pump of the electronically controlled brake system according to the present invention, a pressure chamber for pressurizing oil is formed between the piston tip and the outlet valve, the volume reducing member inside the retainer disposed at the piston tip. Since the volume of the pressure chamber is reduced and the compression ratio is relatively increased as the volume in the pressure chamber is reduced, there is an effect of improving the efficiency of the pump.                     

In addition, in the related art, the opening and closing member is restricted to be moved more than a predetermined distance in the axial direction through the stepped shape of the retainer.

Therefore, there is no need for a separate step in the retainer, so that the shape thereof can be simplified, and there is an effect of making it easy to manufacture.

Claims (4)

A piston provided with a suction flow path for linearly reciprocating in the bore formed in the modulator block and sucking the oil on the low pressure accumulator side, and a pressure chamber installed in the bore to form a pressurizing chamber and reciprocating the piston. In the pump of the electronically controlled brake system having an outlet valve which is opened and closed by the inlet valve, and an inlet valve which is opened and closed opposite to the outlet valve and guides the oil flowing into the suction flow path to the outlet valve. The inlet valve includes an opening and closing member disposed at the tip of the piston to selectively open and close the suction passage, and a retainer in which an oil passage is formed and guides the axial movement of the opening and closing member. And a volume reducing member is provided inside the retainer to reduce the volume of the pressure chamber. The method of claim 1, The retainer has a hollow cylindrical shape, the pump of the electronically controlled brake system, characterized in that it has a constant radius from the portion of the opening and closing member is arranged to the outlet valve side end. The method of claim 1, The opening and closing member of the pump of the electronically controlled brake system characterized in that it has a spherical shape. The method of claim 1, The volume reducing member is provided inside the retainer between the opening and closing member and the outlet valve to limit the movement of the opening and closing member in the axial direction.

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