KR20030087262A - Pump of electronic control brake system - Google Patents

Abstract

PURPOSE: A pump of an electronic control type brake system is provided to reduce the number of parts and prevent wear of seals by integrally forming a valve seat to a valve cap and disposing the valve cap to the outside of a piston and then securing the seals to the valve cap. CONSTITUTION: A pump of an electronic control type brake system has a piston(41) installed in a bore(31a) formed to a modulator block(31); an outlet valve(45) installed to an open end of the bore and opened and shut by the reciprocation of the piston; and an inlet valve(42) installed to an outlet side of a suction passage of the piston and opened and shut oppositely to the outlet valve. The outlet valve forms a compression chamber(43). The outlet valve guides oil of a low-pressure accumulator to the compression chamber. A valve cap(50) is installed between the modulator block and the piston, and the piston reciprocates along the inner wall of the valve cap. A valve seat(45a) forming an orifice(45b) and the valve cap are integrally formed to the front end of the valve cap. When the outlet valve is opened and shut, the outlet valve is secured to the valve seat and the outlet valve opens and shuts the orifice.

Description

Pump of electronic control brake system

The present invention relates to an electronically controlled brake system, and more particularly, to a pump of an electronically controlled brake system for sucking low pressure oil on the low pressure accumulator or reciprocating hydraulic valve side and forcibly pumping it 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. The electronically controlled brake system uses an anti-lock brake system (ABS: Anti-Lock) to prevent the sliding of the wheel during braking. Brake System), a Brake Traction Control System (BTCS) that prevents slippage of the drive wheel during sudden start or acceleration of the vehicle, and the anti-lock brake system and traction control in combination to control the brake hydraulic pressure. A vehicle dynamic control system (VDC) has been developed to maintain a stable state.

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

Accordingly, the low pressure oil of the low pressure accumulator is pressurized by the operation of the pump to be pumped to the high pressure accumulator, and the pressurized oil is transferred to the hydraulic brake or master cylinder assembly. The pump is driven by a motor, which shows 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 the modulator block 1 to reciprocate by an eccentric spindle 2a of a motor 2, and a suction flow path 6a is provided therein. The inlet valve 7 which opens and closes the outlet side of the suction flow path 6a according to the piston 6 formed, the position of this piston 6, and is provided in the open end of the bore 5, and is opposite to the inlet valve 7. It is provided with an outlet valve (8).

The modulator block 1 has a suction port 3 for communicating the inlet side of the suction passage 6a formed in the piston 6 with the low pressure accumulator side, and the inlet side and the outlet of the high pressure accumulator (not shown). A discharge port 4 for communicating the outlet side of the valve 8 is formed.

An inlet valve 7 is provided at the tip of the piston 6, and a seal 9 is provided on the outer periphery of the piston 6 to prevent oil from leaking through a clearance with the inner wall of the bore 5. . The seal 9 has a ring shape and is disposed in the recess 6b recessed along the outer periphery of the piston 6.

The outlet valve 8 is seated on the valve cap 12 provided in the bore 5 of the modulator block 1 and the valve seat 11 embedded in the valve cap 12.

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 8 open and close, the oil introduced is pumped toward the high pressure accumulator while being pressurized.

That is, when the piston 6 moves to the top dead center, the pressure of the oil between the piston 6 and the outlet valve 8 increases, whereby the inlet valve 7 is closed and the outlet valve 8 is closed by the valve seat ( By opening away from 11, the oil is pumped through the discharge port 4 to the high pressure accumulator side.

On the other hand, when the piston 6 moves to the bottom dead center, a low pressure is formed in the space between the tip of the piston 6 and the outlet valve 8, which opens the inlet valve 7 and the outlet valve 8 ) Is seated on the valve seat 11 and closed so that the oil on the low pressure accumulator side passes between the piston 6 and the outlet valve 8 through the suction port 3, the suction flow path 6a and the inlet valve 7. Flows into space.

However, the pump of the conventional electronically controlled brake system has a disadvantage in that the number of assembly parts increases as well as the structure is complicated because the valve seat is separated and assembled from the valve cap.

In addition, since the pump of the conventional electronically controlled brake system has a structure in which the seals disposed in the seating grooves formed in the piston are in direct surface contact with the modulator block which is processed with a relatively low roughness compared to the piston, the seal reciprocating with the piston They are easily worn, and there is a disadvantage in that anodizing treatment is required to improve them.

The present invention is to solve this problem, an object of the present invention is to form a valve seat integrally to the valve cap, and to reduce the number of parts by arranging the valve cap on the outer surface of the piston and the seal seated on the valve cap It is to provide a pump of an electronically controlled brake system to prevent wear of the seal.

1 is a cross-sectional view showing a pump configuration of a conventional electronically controlled brake system.

2 is a hydraulic system diagram of an anti-lock brake system to which the present invention is applied.

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

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

31 ... Modulator block 31a ... Bore

31b ... Suction port 40L, 40R ... Pump

41.Piston 42.Inlet valve

43.Pressure chamber 45 ... Outlet valve

49 ... seal 50 ... valve cap

51 Recessed section 52 Support member

53 ... stopper

The present invention for achieving this object,

Outlet installed in the bore formed in the modulator block and the piston reciprocating linearly by the spindle of the motor and the opening of the bore to form a pressure chamber between the piston end and the opening and closing by the reciprocating motion of the piston In the pump of the electronically controlled brake system having a valve and an inlet valve which is installed at the outlet side of the suction flow path of the piston and opens and closes opposite to the outlet valve to guide oil on the low pressure accumulator side to the pressure chamber,

A valve cap is installed between the modulator block and the piston so that the piston reciprocates along the inner wall of the valve cap, and a valve seat having an orifice formed at the front end of the valve cap is integrally formed with the valve cap. The outlet valve may be seated on the valve seat to close the orifice when the valve is closed.

A recess is formed at a rear end of the inner wall of the valve cap, so that a ring-shaped seal is disposed at the tip of the recess, which borders the rear end of the valve cap.

In addition, the recess has a return spring arranged to apply an elastic force toward the bottom dead center of the piston.

The return spring is supported at both ends by a support member disposed between the seal and the tip of the return spring, and a stopper protruding toward the recess at an approximately midpoint of the piston.

Hereinafter, with reference to the accompanying drawings, preferred embodiments according to the present invention will be described in detail.

Figure 2 is a hydraulic system diagram of the anti-lock brake system to which the present invention is applied, Figure 3 is a cross-sectional view showing the internal configuration of the pump according to the present invention.

Referring to FIG. 2, the anti-lock brake system to which the present invention is applied includes a plurality of solenoid valves 33A and 33B for controlling the braking hydraulic pressure transmission to the hydraulic brake 23 installed on the front wheel and the rear wheel, and a decompression braking operation. The low pressure accumulator 34 in which oil escaping from the hydraulic brake 23 side is temporarily stored, and a pair of pumps 40L (40R) for pumping oil stored in the low pressure accumulator 34 during the boost / hold braking operation. ) And one motor 35 for simultaneously driving the pair of pumps 40L and 40R, and the outlet for reducing pressure pulsation of oil pressurized and discharged by driving the pumps 40L and 40R. It has a high pressure accumulator 36 with an orifice 36a disposed on the side, and 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.

In addition, the pair of pumps 40L and 40R are driven with a single phase difference by one motor 35 to pressurize the oil stored in the low pressure accumulator 34 to pump the high pressure accumulator 36. The structure will be described below with reference to FIG. 3. Here, since the pair of pumps 40L and 40R are symmetrical with respect to the eccentric spindle 35a of the motor 35, only one pump structure is enlarged in FIG.

First, one motor 35 is provided at the central portion of one side of the modulator block 31 so that the spindle 35a protrudes to drive the pumps 40L and 40R. The spindle 35a of the motor 35 is integrally formed with the eccentric shaft 35b and disposed between the pistons 41 of the respective pumps 40L and 40R, whereby a pair of pumps 40L and 40R are mutually connected. Drive with a phase difference of 180 degrees.

The pumps 40L and 40R include a bore 31a formed to be open to the modulator block 31 in the lateral direction, a piston 41 disposed in the bore 31a so as to reciprocate from side to side, and a bore 31a. And the valve housing 44 having the outlet valve 45 built therein to form a pressurizing chamber 43 between the piston 41 and the tip of the piston 41 to prevent the back flow of oil. An inlet valve 42 which is operated opposite to the 45 and allows oil suction of the bottom dead center moving time pressurizing chamber 43 of the piston 41 is provided.

The piston 41 is formed of a rod-shaped rod having a predetermined diameter, and is arranged to contact the spindle 35a of the motor 35 to linearly reciprocate in the bore 31a to allow the inlet valve 42 and the outlet valve ( 45 will be opened and closed alternately. The piston 41 is returned from the top dead center to the bottom dead center by the return spring 46 disposed on the outer circumferential surface of the piston 41. The arrangement of the return spring 46 will be described later.

The outlet valve 45 operates opposite to the inlet valve 42 according to the position of the piston 41 to open and close the discharge passage 44a to be described later. An orifice 45b is formed at the center of the bore 31a. A valve seat 45a disposed at the open end and a sphere 45c supported by the elastic member 45d to contact the orifice 45b of the valve seat 45a.

The elastic member 45d and the sphere 45c of the outlet valve 45 are embedded in the valve housing 44 which seals the open end of the bore 31a, and the valve housing 44 has an outlet of the outlet valve 45. A discharge flow path 44a for linking the side and the discharge port 31c described later is formed. Here, the discharge port 31c is an oil passage processed in the modulator block 31 so that the outlet side of the pumps 40L and 40R and the inlet side (see FIG. 2) of the high pressure accumulator 36 communicate with each other.

Further, the inlet valve 42 is embedded in the suction port 31b processed in the modulator block 31 to guide the oil suction into the pressure chamber 43 in order to compactly configure the internal structure of the pumps 40L and 40R. It is.

That is, the suction port 31b has one end connected to the low pressure accumulator 34 side (see FIG. 2) and the other end is orthogonal to the processing direction of the bore 31 so as to be in direct communication with the pressure chamber 43 in the bore 31a. In the direction of the modulator block 31. The inlet valve 42 is a kind of check valve that is press-fitted at one end of the suction port 31b so as to open when the bottom dead center moves of the piston 41 to allow the oil to be sucked into the pressure chamber 43. A valve housing 42a which is press-fitted to the port 31b and has an orifice 42b formed at the inlet side, a sphere 42c which is built into the valve housing 42a to open and close the orifice 42b, and this sphere 42c ) Is provided with an elastic member 42d disposed between the valve housing 42a and the sphere 42c.

When the piston 41 is moved to the bottom dead center by the inlet valve 42, the pressure chamber 43 is brought into a low pressure state, and the sphere 42c of the inlet valve 42 overcomes the bearing force of the elastic member 42d while the orifice 42b is opened. On the other hand, when the piston 41 moves to the top dead center, the pressure chamber 43 is in a high pressure state, and the sphere 42c of the inlet valve 42 comes into close contact with the periphery of the orifice 42b and closes it.

The valve cap 50 is disposed between the outer circumferential surface of the piston 41 and the bore 31a of the modulator block 31. As one of the characteristic constitutions of the present invention, a valve seat 45a constituting the inlet valve 45 is integrally formed with the valve cap 50 at the tip of the valve cap 50, and the valve seat 45a is provided. An orifice 45b is formed at the center of the. As described above, since the valve cap 50 is integrally formed with the valve seat 45a, the number of parts may be reduced, thereby reducing manufacturing costs and assembly time.

In addition, a recess 51 is formed on the inner circumferential surface of the valve cap 50 so that the return spring 46 may apply an elastic force to the recess 51 so that the piston 41 returns to the bottom dead center. The seal 49 which prevents the hydraulic pressure of the seal 43 from leaking to the outer circumferential surface of the piston 41 is settled.

The seal 49 is formed in a ring shape and disposed at the tip of the recess 51, and the tip of the return spring 46 is provided between the return spring 56 and the recess 51. Supported by).

In addition, a stopper 53 protruding toward the recess 51 is provided at an approximately intermediate point of the outer circumferential surface of the piston 41 so that the piston 41 moves to the top dead center to compress the oil in the pressure chamber 43. In this case, the return spring 46 is compressed by the stopper 53. When the compression process is completed, the stopper 53 is pushed by the elastic restoring force of the return spring 46 so that the piston 41 moves to the bottom dead center. Move it.

A ring-shaped seal 48 is disposed at the rear end of the piston 41 to prevent oil from leaking to the eccentric shaft 35b of the motor 35 through the outer circumferential surface of the piston 41.

Next, the operation and effect of the anti-lock brake system to which the pumps 40L and 40R according to the present invention are applied will be described.

Since the anti-lock brake system controls the braking state of the vehicle according to the three modes of braking pressure decompression, boosting, and holding to prevent slippage of the vehicle, each solenoid valve 33A is operated together with the driving of the pumps 40L and 40R. The opening and closing operation is repeatedly performed so that 33B controls the hydraulic pressure transmission to the hydraulic brake 23 side. That is, when the braking pressure in the hydraulic brake 23 is greater than the road surface condition in a state where the driver presses the brake pedal 20 and the braking force is exerted by the braking hydraulic pressure formed through the power booster 21 and the master cylinder assembly 22. In this case, the ECU 32 closes the NO type solenoid valve 33A and opens the NC type solenoid valve 33B (see FIG. 2).

If the braking pressure decompression state lasts for a long time or the vehicle moves 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 of the vehicle is increased, thereby reducing the vehicle braking efficiency. The ECU 32 determines this situation on the basis of the signals input from each wheel sensor 24, and pumps 40L and 40R through the motor 35 to increase the braking pressure in the hydraulic brake 23. Drive it. Therefore, the oil stored in the low pressure accumulator 34 is pressurized and supplied to the high pressure accumulator 36 side, and the power is continuously supplied to the hydraulic brake 23 through the NO type solenoid valve 33A which is opened and operated. This increases the braking hydraulic pressure.

The oil stored in the low pressure accumulator 34 at the time of the increased pressure braking is pressurized by driving the pumps 40L and 40R, and is supplied to the NO type solenoid valve 33A while passing through the high pressure accumulator 36 and the orifice 36a. If only the pump 40L (40R) drive according to the present invention will be described in more detail as follows.

That is, when the piston 41 slides to the top dead center in the bore 31a as the eccentric spindle 35a of the motor 35 rotates (arrow A direction), the return spring 46 is stopped by the stopper 53. As it is compressed, the oil pressure in the pressurizing chamber 43 is increased. As a result, the inlet valve 42 is closed and the outlet valve 45 is opened, so that the oil is discharged through the discharge passage 44a and the discharge port 31c. It is discharged to the (36) side.

On the other hand, when the stopper 53 is pushed backward by the reaction force of the return spring 46 and the piston 41 slides to the bottom dead center (arrow B direction), the pressurizing chamber 43 is brought into a low pressure state. Inlet valve 42 is open and 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.

As the piston 41 linearly reciprocates by the driving of the motor 35 during the control of the antilock brake system as described above, the oil on the low pressure accumulator 34 side is sucked into the pressure chamber 43 through the suction port 31b. The pressure is supplied to the high pressure accumulator 36 while being pressurized.

At this time, a seal 49 for preventing oil from leaking out through the outer circumferential surface of the piston 41 is seated in the recess 51 of the valve cap 50 so that the modulator block moves with the piston 41. Since it comes into contact with the outer circumferential surface of the piston 41 which is processed much smoother than the inner surface of the bore 31a of (31), the seal 49 will not wear even if used for a long time.

As described in detail above; According to the pump of the electronically controlled brake system according to the present invention, the valve seat for installing the outlet valve is integrally formed with the valve seat for seating the sphere of the outlet valve in the valve cap for installing the outlet valve, thereby reducing the number of parts. Therefore, the manufacturing time and manufacturing cost is reduced.

In addition, the valve cap is installed to surround the outer circumferential surface of the piston, and since the seal is disposed on the valve cap to prevent oil from leaking, the seal does not wear even when used for a long time.

Claims (4)

Outlet installed in the bore formed in the modulator block and the piston reciprocating linearly by the spindle of the motor and the opening of the bore to form a pressure chamber between the piston end and the opening and closing by the reciprocating motion of the piston In the pump of the electronically controlled brake system having a valve and an inlet valve which is installed at the outlet side of the suction flow path of the piston and opens and closes opposite to the outlet valve to guide oil on the low pressure accumulator side to the pressure chamber, A valve cap is installed between the modulator block and the piston so that the piston reciprocates along the inner wall of the valve cap, and a valve seat having an orifice formed at the front end of the valve cap is integrally formed with the valve cap. And the outlet valve is seated on the valve seat to close the orifice during the closing operation of the valve. The method of claim 1, A recess is formed at a rear end of the inner wall of the valve cap, and a ring-shaped seal is arranged at a front end of the recess, which borders the rear end of the valve cap. . The method of claim 2, The recess of the pump is an electro-controlled brake system, characterized in that the return spring is arranged to apply an elastic force toward the bottom dead center. The method of claim 3, The return spring is electrically controlled by the support member disposed between the seal and the front end of the return spring, and both ends of the return spring are supported by a stopper protruding toward the recess at an approximately midpoint point of the piston. Pump of the system.