KR100444817B1 - Solenoid valve for brake traction control system - Google Patents

Abstract

The present invention relates to a brake traction control system that prevents road slippage of wheels. In particular, the brake traction control system allows the valve to open by itself when excessive braking hydraulic pressure is applied to the wheels by the operation of the hydraulic hydraulic pump. It relates to a solenoid valve for.

The solenoid valve for the brake traction control system according to the present invention includes a valve core having an inlet and an outlet for fluid flow on one side, an armature removably installed in the valve dome which seals one end of the valve core, and the armature retreating. And a plunger installed in the valve core so as to open and close the inlet of the valve core in conjunction with the armature movement of the armature, and the plunger and the armature when the power source is not applied to the coil. In including a return spring for opening the inlet of the valve core, between the armature and the end of the adjacent plunger is installed a retractable safety spring so that the flow path can be opened by pushing the plunger by the inlet pressure of the valve core.

Description

Solenoid valve for brake traction control system {SOLENOID VALVE FOR BRAKE TRACTION CONTROL SYSTEM}

The present invention relates to a brake traction control system that prevents road slippage of a vehicle wheel, and more particularly, a brake that allows a valve to open by itself when an excessive braking hydraulic pressure is applied to a wheel side by an operation of a hydraulic pump. A solenoid valve for a traction control system.

Recently, among hydraulic brake devices mounted on a vehicle, there is an anti-lock brake system (hereinafter referred to as 'ABS') to prevent the slip of the wheel by periodically regulating the braking hydraulic pressure transmitted to the wheel side. .

As shown in FIG. 1, the vehicle ABS includes a NO (Normal Open) solenoid valve 3 installed in the middle of a hydraulic line connected from a master cylinder 1 to a wheel cylinder 2 on a wheel side, and on a wheel side. An NC (Normal Close) solenoid valve (4) provided in a return flow path for returning oil is provided. In addition, the ABS is provided with a hydraulic pump 5 for re-pressurizing the oil returning from the wheel side to generate a braking pressure, and the low pressure accumulator 6 and the high pressure accumulator 7 are provided on the upstream and downstream sides of the hydraulic pump 5. do. These devices are controlled by an ECU (ELECTRIC CONTROL UNIT, not shown). That is, the ECU controls the opening and closing of the NO and NC solenoid valves 3 and 4 to control the braking hydraulic pressure supplied to the wheel side, and simultaneously controls the driving of the hydraulic pump 5 to return the fluid returned along the hydraulic line. Re-pressurization to the side allows intermittent braking.

In addition, such a vehicle ABS is provided with a brake traction control system (BTCS) to prevent the wheels and road surface slip phenomenon when the vehicle starts to allow the vehicle to start smoothly.

The brake traction control system has a separate hydraulic line 8a for connecting the outlet hydraulic line of the master cylinder 1 and the inlet hydraulic line of the hydraulic pump 5. In the hydraulic line 8a, the reciprocating hydraulic valve 8 is installed to close the flow path when the driver presses the brake pedal 1a and the braking hydraulic pressure is transmitted. In addition, the hydraulic line 9a connecting the outlet side of the master cylinder 1 and the outlet side of the high-pressure accumulator 7 has a traction control solenoid valve 9, hereinafter, referred to as a `` solenoid valve for TC ''. Is called). The pressure regulating valve 10 is installed in the bypass passage 10a which communicates the outlet side of the master cylinder 1 with the outlet side of the high pressure accumulator 7.

In this configuration, the traction control system operates the hydraulic pump 5 through the control of the ECU when the slip phenomenon of the vehicle wheel is detected regardless of the driver operating the brake pedal 1a, so that the NO solenoid valve 3 is operated. Brake pressure is applied to the wheel cylinder (2) on the wheel side through. At this time, since the TC solenoid valve 9 and the NC type solenoid valve 4 remain closed, the oil passes through the reciprocating hydraulic valve 8 from the outlet side of the master cylinder 1 to the hydraulic pump 5. Supplied, the hydraulic pump (5) to press this to brake the wheel is made to prevent road slip phenomenon. In this case, when the outlet side braking hydraulic pressure of the hydraulic pump 5 is too high, the pressure regulating valve 10 is opened so that the oil is bypassed through the bypass passage 10a and the braking hydraulic pressure applied to the wheel side is always maintained in an appropriate state.

However, the conventional brake traction control system configured as described above should have a separate bypass passage 10a to prevent the pressure on the outlet side of the hydraulic pump 5 from excessively rising, and the bypass passage 10 has a hydraulic pump 5 Since a separate pressure regulating valve 10 is provided to sense the pressure at the outlet side to open the valve, the configuration of the brake system is complicated and the device has a large volume.

The present invention is to solve such a problem, an object of the present invention is to open the solenoid valve for TC when the outlet side pressure of the hydraulic pump is more than the predetermined pressure to allow the oil to flow to the master cylinder, a separate bypass flow path and It is to provide a solenoid valve for a brake traction control system that enables the braking pressure of the hydraulic pump outlet side to be properly adjusted without a pressure regulating valve.

1 is a hydraulic circuit diagram of an anti-lock brake system to which a conventional brake traction control device is applied.

2 is a hydraulic circuit diagram of an anti-lock brake system to which a solenoid valve for a brake traction control system according to the present invention is applied.

3 is a cross-sectional view showing the configuration of a solenoid valve for a traction control system according to the present invention.

4 and 5 are perspective views showing the configuration of the safety spring according to the present invention, showing different embodiments.

Explanation of symbols on the main parts of the drawings

20: master cylinder, 24: NO solenoid valve,

25: NC solenoid valve, 26: hydraulic pump,

27: low pressure accumulator, 28: high pressure accumulator,

29: reciprocating hydraulic valve, 30: TC solenoid valve,

31: valve core, 32: valve dome,

33: amateur, 34: female coil,

35: plunger, 36: valve seat,

37: return spring, 38: safety spring.

Solenoid valve for brake traction control system according to the present invention for achieving the above object is a valve core formed with a through hole in the longitudinal direction in the center and the inlet and outlet for the flow of fluid on one side, and one end of the valve core An armature removably installed inside the valve dome to seal the valve, a female coil installed outside the valve dome to advance and retract the armature, and the valve to open and close the inlet of the valve core in conjunction with the armature retraction movement. A solenoid valve for a brake traction control system including a plunger removably installed inside the through hole of the core and a return spring for returning the plunger and the amateur to open the inlet of the valve core when power is not applied to the excitation coil. Wherein the amateur and the plu adjacent thereto Of doedoe, the safety spring stretch that can be installed by the inlet pressure of the valve core, so that the plunger is pushed may open the flow path between the ends and of the safety spring elasticity characterized in that a is greater than the return spring elasticity.

In addition, the safety spring is characterized in that the plate spring is formed in a conical shape of a disk with a hole in the center.

In addition, the safety spring is characterized in that the circular spring washer having a hole in the center.

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

In the vehicle ABS to which the present invention is applied, as shown in FIG. 2, a NO (Normal Open) type solenoid installed in the middle of a hydraulic line connected from the master cylinder 20 to the wheel-side wheel cylinder 23 to open and close the supply flow path. The valve 24 is provided, and the NC (Normal Close) solenoid valve 25 which opens and closes the flow path of the fluid returned from the wheel side is provided. At this time, when the NO type solenoid valve 24 is open, the NC type solenoid valve 25 is closed to apply braking pressure to the wheel side, and when the NO type solenoid valve 24 is closed, the NC type solenoid valve 25 is closed. Open to release the brake pressure.

In addition, the ABS includes a hydraulic pump 26 for repressurizing oil returned from the wheel-side wheel cylinder 23 to an upstream side of the NO-type solenoid valve 24, and a buffer space (upper and downstream of the hydraulic pump 26) is provided. The low pressure accumulator 27 and the high pressure accumulator 28 which comprise BUFFER) are provided. At this time, the low pressure accumulator 27 installed upstream of the hydraulic pump 26 functions to temporarily store the brake oil returning from the wheel side and then supply the hydraulic fluid to the hydraulic pump 26 side, and the downstream side of the hydraulic pump 26. The high-pressure accumulator 28 installed in the function serves to attenuate the pressure pulsation according to the operation of the hydraulic pump 26 while the oil pressurized in the hydraulic pump 26 is temporarily stored. And these devices are controlled by the ECU (ELECTRIC CONTROL UNIT, not shown). That is, the ECU controls the NO-type and NC-type solenoid valves 24 and 25 to open and close the flow path supplied to the wheel side, and also controls the driving of the hydraulic pump 26 to the low pressure accumulator 27 through the return flow path. The returned fluid is re-pressurized to the wheel side so that intermittent braking is achieved.

In addition, such a vehicle ABS is provided with a brake traction control system (BTCS) that prevents slippage of wheels and road surfaces at the start of the vehicle so that the vehicle starts smoothly.

The brake traction control system has a separate hydraulic line 29a connecting the outlet hydraulic line of the master cylinder 20 and the inlet hydraulic line of the hydraulic pump 26, and is normally open to the weaning pressure line 29a. While maintaining the state, when the driver presses the brake pedal 22 and the braking hydraulic pressure is transmitted, a reciprocating hydraulic valve 29 is installed to close the flow path. This is to ensure that the braking hydraulic pressure is transmitted only to the wheel side of the vehicle when the driver normally presses the brake pedal 22. In addition, the brake traction control system maintains the normally open state in the hydraulic line connecting the outlet side of the master cylinder 20 and the outlet side of the high-pressure accumulator 28, and when the road slip of the wheel occurs due to a sudden start of the vehicle, etc. By closing the valve, the TC solenoid valve 30 is installed so that the braking pressure generated by the driving of the hydraulic pump 26 can be transmitted to the wheel side. In this case, the solenoid valve for TC 30 according to the present invention is characterized in that the opening of the valve is opened when the pressure of the outlet side flow path of the hydraulic pump 26 is greater than or equal to the predetermined pressure so that a part of the oil can flow toward the master cylinder 20. .

Referring to FIG. 3, the TC solenoid valve 30 has a longitudinal through hole 31c formed at the center thereof, and a magnetic inlet 31a and outlet 31b for introducing and discharging oil at a lower end thereof. The valve core 31 is provided. And the upper end of the valve core 31 is covered with a valve dome 32 provided in a thin cylindrical shape is coupled. In addition, a cylindrical armature 33 is installed inside the valve dome 32 so that the predetermined section can be moved in and out in the longitudinal direction. And the outer surface of the valve dome 32 is applied to receive a cylindrical excitation coil 34 for advancing and retracting the armature 33 is coupled to the.

In addition, a rod-shaped plunger 35 capable of advancing and retracting in the longitudinal direction is installed in the through-hole 31c of the valve core 31, and one end of the plunger 35 is provided at the inlet 31a of the valve core 31. It is arranged to be adjacent to the valve seat 36, and the other end is arranged to be adjacent to the armature 33. At this time, the sphere 35a blocking the flow of oil by blocking the flow path of the valve seat 36 when the plunger 35 is advanced by the operation of the armature 33 at the end of the plunger 35 adjacent to the valve seat 36. Is combined. In addition, at the end of the plunger 35 adjacent to the valve seat 36, a return spring 37 for retracting the plunger 35 and the armature 33 to open the flow path when power is not applied to the excitation coil 34 is provided. Is installed. The return spring 37 is supported with one end supported by the valve seat 36 and the other end partially fitted to the end of the plunger 35.

And between the other end of the plunger 35 and the amateur 33 is provided a safety spring 38 for elastically supporting between the plunger 35 and the amateur (33). At this time, the safety spring 38 must be able to withstand a relatively large load in a state installed in a narrow space between the plunger 35 and the amateur 33, and should be a structure capable of maintaining a suitable height in the free state. To this end, the safety spring 38 is made of a circular spring washer with a hole in the center as shown in Figure 4, or a plate spring formed in a conical shape of a disk with a hole in the center as shown in FIG. It is good.

In addition, the elasticity of the safety spring 38 is greater than the elasticity of the return spring 37 provided on the valve seat 36 side, so that the safety spring 38 is the elastic spring of the return spring 37 when the armature 33 is operated. Win and be able to push the plunger 35. And when the sphere 35a of the plunger 35 contacts the valve seat 36 and the inlet 31a of the valve core 31 is applied in the state in which the flow path was closed, the pressure of this oil will be a safety spring 38 ) By pushing the plunger 35 to allow fluid to flow into the gap between the valve seat 36 and the sphere 35a. That is, the fluid pressure at the outlet side of the hydraulic pump 26 is determined by the elasticity of the safety spring 38.

The following describes the operation of the vehicle ABS to which the solenoid valve for TC of such a configuration is applied.

When the driver presses the brake pedal 22, the back pressure is generated by the pressure difference in the power supply device 21, the master cylinder 20 receives the amplified force to form a braking hydraulic pressure, this hydraulic pressure is a solenoid valve NO It is supplied to the wheel cylinder 23 of each wheel side through 24, and exhibits a braking force. At this time, when excessive braking pressure is transmitted, a slip phenomenon occurs that the tire of the vehicle stops rotating and slips on the road surface. The slip phenomenon is detected through a wheel sensor (not shown) mounted on the wheel side of the vehicle, and the detected information is detected. It is delivered to an ECU (not shown). At this time, the ECU opens the NC solenoid valve 25 to release oil in the wheel cylinder 20 to release the temporary braking to prevent slip phenomenon of the wheel.

In addition, the oil discharged through the NC-type solenoid valve 25 is moved to the low pressure accumulator 27 and stored for a while, the oil of the low pressure accumulator 27 is re-pressurized by the driving of the hydraulic pump 26 and the high pressure accumulator 28 ) And the oil of the high-pressure accumulator 28 is supplied to the upstream side of the NO-type solenoid valve 24 to form a braking pressure. That is, the ABS for the vehicle continuously controls the operation by the ECU, thereby applying an intermittent braking pressure to the wheel cylinder 23 to allow stable braking of the vehicle.

On the other hand, regardless of the driver operating the brake pedal 22, the brake traction control system is activated when a slip phenomenon of the wheel of the vehicle is sensed by sudden start of the vehicle or the like. At this time, the TC solenoid valve 30 and the NC solenoid valve 25 are closed by the control of the ECU, and the braking hydraulic pressure is applied to the wheel side through the NO type solenoid valve 24 while the hydraulic pump 26 is driven. All. In addition, the oil is supplied to the hydraulic pump 26 through the reciprocating hydraulic valve 29 at the outlet side of the master cylinder 20, the hydraulic pump 26 is pressurized to make the brake of the wheel.

When the braking hydraulic pressure applied to the wheel side of the hydraulic pump 26 is too high in this process, the flow path of the solenoid valve 30 for TC is closed by the pressure of the outlet side of the hydraulic pump 26. As it opens, the oil of the hydraulic pump 26 exits and flows toward the master cylinder 20. Accordingly, the braking pressure applied to the wheels is properly maintained to prevent the wheels from completely stopping, thereby smoothly starting the vehicle.

Referring to FIG. 3, when the power is applied to the excitation coil 34 of the solenoid valve 30 for TC and the armature 33 moves forward toward the valve core 31, the armature 33 is a safety spring. The pressure spring of the valve seat 36 is closed by pushing the plunger 35 toward the valve seat. That is, the flow path of the TC solenoid valve 30 is closed.

In this state, when the pressure of the fluid applied to the inlet 31a of the valve core 31 becomes excessively high, the pressure of the fluid pushes the sphere 35a of the plunger 35 to open the flow path. The safety spring 38 between the 33 and the plunger 35 is slightly compressed by the plunger 35 which is pushed back by the hydraulic pressure. That is, the flow path is opened while the plunger 35 and the safety spring 38 are pushed out by the hydraulic pressure of the inlet 31a, thereby preventing the excessive rise of the pressure at the outlet side of the hydraulic pump 26.

As described in detail above, in the solenoid valve for the brake traction control system according to the present invention, when the outlet side pressure of the hydraulic pump is greater than or equal to the predetermined pressure, the flow path is opened while the plunger is retracted by the pressure of the fluid, thereby opening the hydraulic pump outlet side. By allowing oil to flow into the master cylinder, there is an effect of properly adjusting the braking pressure at the outlet side of the hydraulic pump without a separate bypass flow path and a pressure control valve. In addition, it is possible to simplify the configuration of the brake system to reduce the volume of the device, as well as to increase the manufacturability of the device.

Claims (4)

A valve core having a longitudinal through hole formed at a center thereof and an inlet and an outlet for fluid flow at one side thereof, an armature removably installed inside the valve dome sealing one end of the valve core, Power is applied to the excitation coil, an excitation coil installed outside the valve dome, a plunger installed in the through hole of the valve core so as to open and close the inlet of the valve core in association with the advance movement of the armature, and the excitation coil. A solenoid valve for a brake traction control system comprising a return spring for returning the plunger and the armature to open the inlet of the valve core when not in operation. Between the armature and the end of the plunger adjacent thereto is installed a safety spring that can be expanded and contracted to open the flow path by pushing the plunger by the inlet pressure of the valve core, the safety by the elasticity of the return spring before applying the current Solenoid valve for brake traction control system, characterized in that the spring is not pressed. The method of claim 1, The solenoid valve for the brake traction control system, characterized in that the elasticity of the safety spring is larger than the elasticity of the return spring. The method of claim 1, The safety spring is a solenoid valve for a brake traction control system, characterized in that the plate spring is formed in a conical shape of a disk with a hole in the center. The method of claim 1, The safety spring is a solenoid valve for a brake traction control system, characterized in that the circular spring washer with a hole in the center.