KR100413257B1 - Normal open type solenoid valve for ABS - Google Patents

Abstract

The present invention relates to a NO type solenoid valve for an anti-lock brake system. The object of the present invention is to provide a double orifice to improve braking response and effectively prevent noise generation during braking hydraulic pressure control by ABS control.

According to the NO-type solenoid valve 30 for an anti-lock brake system according to the present invention, the braking hydraulic pressure transmitted from the master cylinder 10 during the normal braking action is formed on the movable piston 37 and the branch passage 37d and the valve seat ( It is transmitted smoothly through the main orifice (36a) formed in the 36 to improve the braking response, when the braking hydraulic pressure is controlled by ABS control, the braking hydraulic pressure is formed on the auxiliary orifice (37e) and the main orifice (37) 36a), the pressure is gradually increased and transmitted stably, thereby effectively preventing the occurrence of noise and at the same time, the braking action is also stable.

Description

ENO type solenoid valve for anti-lock brake system {Normal open type solenoid valve for ABS}

The present invention relates to an anti-lock brake system, and more particularly, to an NO-type solenoid valve for an anti-lock brake system for maintaining braking hydraulic pressure by closing or opening during ABS control.

In general, the vehicle is equipped with a hydraulic brake mounted on the front wheel and the rear wheel for the purpose of deceleration or stopping while driving, and a hydraulic power and a master cylinder that forms the brake hydraulic pressure and transmits it to the hydraulic brake side. If the braking pressure is greater than the road surface condition or the road condition is changed during the maintenance state, and the frictional force from the hydraulic brake generated by the braking pressure is greater than the braking force generated from the tire or the road surface of the vehicle, the tire slips on the road surface. Is generated.

In order to effectively prevent such slip phenomenon and to obtain a strong and stable braking force, the anti-lock brake system is provided with a plurality of solenoid valves, ECUs, accumulators and pumps for controlling braking hydraulic pressure transmission to the hydraulic brake side.

The solenoid valve is divided into a normally open solenoid valve which is disposed upstream of the hydraulic brake and is normally kept open, and a normally closed solenoid valve which is arranged downstream and normally closed.

Referring to FIG. 1, a conventional normally open solenoid valve (hereinafter, referred to as a NO type solenoid valve) has an inlet 1a and an outlet 1b formed therein, and an orifice 1c is disposed in an axial direction in a valve housing 1. ), A solenoid 2 on which the coil 2a is wound so as to form a magnetic force upon application of current, and a valve device 3 for retracting and moving the orifice 1c by the magnetic force.

The valve housing (1) is compactly mounted on an aluminum modulator block (4). The inlet (1a) processed in communication with the bottom of the valve housing (1) has a master cylinder (not shown) and a pump (not shown) at the outlet side. The outlet 1b, which is connected to the hydraulic line and processed on the side of the valve housing 1, is connected to the inlet (not shown) of the hydraulic brake (not shown) and the normally closed solenoid valve (not shown).

In addition, the valve device 3 includes an armature 3a, which is built in the cylindrical sleeve 3d so as to move forward and backward, and a coil spring type support spring 3e for restoring the armature 3a. The armature 3a is provided with a plunger 3b extending in the shape of a rod and provided with a valve seat 3c at its tip. In general, the valve seat 3c of the plunger 3b is orifice by an elastic bearing force of the support spring 3e. (1c) is kept open. (In the case of a normally closed solenoid valve, the valve seat of the plunger is normally configured to keep the orifice closed.)

In the NO type solenoid valve configured as described above, when power is applied to the solenoid 2 during ABS operation, a magnetic force is formed at the periphery of the solenoid 2, whereby the armature 3a overcomes the elastic force of the support spring 3e. Come down. As the plunger 3b descends integrally with the armature 3a, the valve seat 3c is seated on the upper part of the orifice 1c, and the orifice 1c is closed. Accordingly, the braking hydraulic pressure generated in the master cylinder or the pump is stopped from being transmitted to the hydraulic brake side.

When the power supply is cut off, the armature 3a rises upward due to the elastic restoring force of the support spring 3e, whereby the valve seat 3c of the plunger 3b opens the orifice 1c again. The braking hydraulic pressure formed at the cylinder or the pump side is transmitted to the hydraulic brake side through the orifice 1c.

The conventional NO type solenoid valve typically uses a large orifice (1c) having a diameter of about 0.63-0.7mm, and during a general braking operation, it is directly transmitted to the hydraulic brake side through a large orifice (1c) of braking hydraulic pressure formed in the master cylinder. Therefore, the braking response is good. However, if the vehicle slips during braking, braking hydraulic pressure transmission must be interrupted. If the orifice 1c is large, the ABS control becomes difficult, and when the orifice 1c is closed and opened, a large amount of oil is instantaneously opened. Since it is trying to propagate, significant noise is generated. That is, a significant braking hydraulic pressure supplied from the master cylinder or the pump outlet side is applied upstream of the orifice 1c while the orifice 1c is closed. In this state, the valve housing having a relatively low pressure is opened when the orifice 1c is opened. (1) Braking hydraulic pressure is suddenly delivered to the hydraulic brake side through the inside and the outlet 1b. At this time, since a considerable pressure difference is formed on the upstream side and the downstream side of the orifice 1c, a considerable hydraulic shock is generated at these boundary portions, whereby a noise is generated along with a cooling phenomenon, and the sound wave shock proceeds. The braking action becomes unstable.

On the contrary, when the orifice 1c is made small, the ABS control is easy, but the braking hydraulic pressure transmission formed in the master cylinder is not immediately performed during the normal braking operation, and thus there is a problem that the braking response is inferior.

The present invention is to solve this problem, an object of the present invention is to configure the orifice to improve the braking response and at the same time anti-lock brake to effectively prevent the occurrence of noise during braking hydraulic pressure control by ABS control It provides NO type solenoid valve for system.

1 is a cross-sectional view of a conventional NO solenoid valve used in an antilock 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 of the NO type solenoid valve according to the present invention.

4 to 7 show the operating state of the NO-type solenoid valve according to the present invention.

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

30..NO solenoid valve 31..Valve housing

32..Solenoids 33..Amateur

34.Plunger 36.Valve seat

37. Movable piston 38. Second elastic body

39..Hydraulic guide member

In order to achieve the above object, the present invention is provided with an outlet associated with a hydraulic brake side and a conventional accommodating portion at one end inserted into and coupled to a bore of a modulator block, and a valve housing fitted with a sleeve at another end thereof, and fitted into an accommodating portion of a valve housing. The main orifice is provided at the center of the upper side, and the valve seat is formed in the hydraulic chamber inside the lower side, and the sleeve is embedded in the armature and the armature, which moves back and forth by the solenoid, interlocking with the armature and the armature through the valve housing to open and close the main orifice. A plunger having a sphere at its tip to elastically support, a first elastic body disposed between the plunger and the valve seat so that the main orifice is kept open in an ordinary state by elastic support of the plunger, and one end of the bore bottom of the modulator block in the hydraulic chamber of the valve seat Inlet that is slidably mounted in and associated with the master cylinder inside And a second elastic body disposed between the valve housing and the movable piston so that the main piston and the auxiliary orifice are normally spaced apart from each other by elastically supporting the movable piston, and the auxiliary piston being provided at the center thereof in association with the main orifice. It is a configuration characterized in that.

According to this configuration, the braking hydraulic pressure delivered from the master cylinder during the normal braking action is smoothly transmitted through the main orifice, and the braking response is improved, and the braking hydraulic pressure is formed in the movable piston during the braking hydraulic pressure control by the ABS control. The pressure is gradually increased through the main orifice and it is stably transmitted to prevent noise from occurring.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. 2 is a hydraulic system diagram of an anti-lock brake system to which the present invention is applied, and FIGS. 3 to 7 show an internal structure and an operating state of the NO type solenoid valve according to the present invention.

As shown in FIG. 2, the anti-lock brake system to which the present invention is applied includes a plurality of solenoids for controlling the braking hydraulic pressure generated in the master cylinder 10 to be transmitted to the hydraulic brakes 20 installed on the front and rear wheels of the vehicle, respectively. A pair of a low pressure accumulator 50 in which oil discharged from the valves 30 and 40, the hydraulic brake 20 side is temporarily stored, and a motor 60 for pumping oil stored in the low pressure accumulator 50 Of the pump 61 and the high pressure accumulator 70 for attenuating the pressure pulsation of the oil generated when the pump 61 is driven, which are compactly installed in the modulator block 80.

The solenoid valves 30 and 40 are respectively disposed in association with the upstream side and the downstream side of the hydraulic brake 20 so as to control the hydraulic flow to the hydraulic brake 20 side. NO-type solenoid valve 30 is to be connected to the downstream and is divided into the NC-type solenoid valve 40 that is normally kept closed.

Referring to FIG. 3, the NO type solenoid valve 30 according to the present invention has a valve housing 31 having an end coupled to a modulator block 80, a solenoid 32 forming a magnetic force when a power is applied, and interacts with a magnetic force. The armature 33 is provided at the end of the valve housing 31, the armature 33 is provided with a plunger 34, the valve seat 36 is provided with a main orifice (36a), the upper end in the valve seat 36 The second elastic body 38 elastically supporting the movable piston 37 and the movable piston 37 in which the inlet 37c and the auxiliary orifice 37e and the auxiliary orifice 37e are provided in the axial direction and the movable piston 37 are downwardly installed. It is provided.

The valve housing 31 is press-fitted to a bore 81 whose lower end is stepped on the modulator block 80, and the receiving part 31a is fitted to the lower end of the valve housing 31 to fit the valve seat 36. It is provided, the outlet 31b is processed to be connected to the inlet (not shown) side of the hydraulic brake 20 and the NC-type solenoid valve (not shown). In addition, a cylindrical sleeve 35 is coupled to an upper portion of the valve housing 31 protruding out of the modulator block 80.

The armature 33 is installed on the inner upper side of the sleeve 35 so as to be able to move up and down, wherein a rod-shaped plunger 34 extends downwardly and passes through the inside of the valve housing 31 so that the main portion of the valve seat 36 can be moved. It is configured adjacent to the orifice 36a. At the tip of the plunger 34, a sphere 34a is provided to open and close the upper portion of the main orifice 36a, and a first elastic body 34b is installed to keep the main orifice 36a open. The first elastic body 34b is provided as a coil spring and is disposed between the plunger 34 and the valve seat 936 to elastically support the plunger 34 in the upward direction.

The solenoid 32 is arranged so that the coil 32a is wound around the bobbin 32b to surround the sleeve 35, and a magnetic force for operating the armature 33 when power is applied under the control of an ECU (not shown). To form.

The valve seat 36 is forcibly fitted to the receiving portion 31a of the valve housing 31. A main orifice 36a having a predetermined diameter is formed on the upper portion of the valve seat 36, and a hydraulic pressure chamber 36b is provided on the lower portion so that the upper end 37a of the movable piston 37 is slidably inserted therein. Upper and lower portions of the main orifice 36a are provided with a first valve seat surface 36c on which the sphere 34a is seated and a second valve seat surface 36d on which the upper end of the movable piston 37 is seated.

On the other hand, the movable piston 37 is slidably coupled to the upper end 37a of the hydraulic chamber 36b of the valve seat 36, and the other end 37b is slidable to the bottom of the bore 81 of the modulator block 80. To be placed. An outer ring 37g of elastic material is provided on the outer circumference of the movable piston 37 to prevent oil leakage, and a lip seal 37g is also formed on the outer circumference of the lower piston 37b of the movable piston 37. The movable piston 37 is provided with an inlet 37c and a pair of branch passages 37d and an auxiliary orifice 37e arranged in the axial direction and connected to the master cylinder 10 side, and movable on the center of the upper end 37a. A third valve seat surface 37f is provided to contact the second valve seat surface 36d when the piston 37 is lifted to cover the lower portion of the main orifice 36a. The pair of branch passages 37d are formed so as to branch in both directions so that the upper portion of the inlet 37c communicates with the hydraulic chamber 36b. The third valve seat surface 37f has a predetermined pressure difference between the inlet 37c side and the outlet 31b side due to the closing operation of the main orifice 36a through the sphere 34a in the braking pressure holding mode of the ABS. When the movable piston 37 is raised, it consists of a predetermined curvature surface to be seated on the second valve seat surface 36d, wherein the auxiliary orifice 37e is provided in the axial direction, and the inlet 37c and the main orifice 36a are provided. To communicate. At this time, the diameter of the auxiliary orifice 37e is preferably smaller than the main orifice 36a.

The second elastic member 38 is installed on the lower circumference of the lower end of the valve housing 31 to support the movable piston 37 downward. That is, the second elastic body 38 formed of the coil spring is movable with the valve housing 31 so that the movable piston 37 is elastically supported in the downward direction so that the main orifice 36a and the auxiliary orifice 37e are normally spaced apart. It is disposed between the piston 37, which is compressed when a predetermined pressure difference occurs between the inlet 37c side and the outlet 31b side in the braking pressure holding mode in which the main orifice 36a is closed. It is designed to move up and down. In this embodiment, the spring constant is set to compress the second elastic body 38 when the pressure difference between the inlet 37c and the outlet 31b is 13 Bbar or more.

Further, at the bottom of the movable piston 37, a hydraulic guide member 39 for guiding oil supplied from the master cylinder 10 side to the hydraulic chamber 36b side and a filter 39c for preventing the inflow of foreign matters are disposed. The hydraulic guide member 39 extends into the inlet 37c and has an outward flange 39b of which diameter is extended so as to be seated at the bottom of the bore 81 of the conventional guide portion 39a and the modulator block 80 of which the inside is middle east. It is provided. In addition, the filter 39c is formed in a mesh, and is compactly installed at the bottom of the outward flange 39b of the hydraulic guide member 39 to prevent foreign substances from entering the inlet 37c.

Next will be described the operation and effect of the NO-type solenoid valve according to the present invention configured as described above.

First, the general braking action is as follows. When the driver presses the brake pedal, the braking hydraulic pressure generated in the master cylinder 10 is transmitted to the hydraulic brake 20 through the NO type solenoid valve 30. That is, since normally the NO-type solenoid valve 30 is kept in the open state, the braking hydraulic pressure is as shown in Figure 4, the guide portion 39a → the movable piston 37 of the hydraulic guide member 39 Inlet (37c) → Branch flow path (37d) and auxiliary orifice (37e) → Hydraulic chamber (36b) → Main orifice (36a) → Delivery to the hydraulic brake (20) side through outlet (31b) (braking direction) Is done. At this time, the braking hydraulic pressure is smoothly transmitted to the main orifice 36a through the guide portion 39a, the branch flow passage 37d, and the auxiliary orifice 37e, so that a braking response is generated quickly. On the contrary, when the driver releases the brake pedal little by little or completely, the braking hydraulic pressure in the hydraulic brake 20 is returned in the reverse order through the open NO solenoid valve 30 so that the braking force is reduced or the braking action is completely released.

And ABS control to prevent vehicle slip is largely controlled by three modes of braking pressure decompression, boosting, and maintenance, and each control state is not controlled to the same state on all four wheels of the vehicle. Depending on the state, the control is controlled separately, ie a mixture of three modes.

First, the braking pressure decompression mode will be described. If the braking pressure in the hydraulic brake 20 is greater than the road surface condition while the braking operation is being performed, the braking pressure should be lowered to an appropriate pressure. In the ECU (not shown), the NO type solenoid valve 30 is closed and the NC type solenoid valve 40 is operated. ) Open operation. That is, in the NO type solenoid valve 30, when a power is applied to the solenoid 32 to form a magnetic force, as shown in FIG. 5, the plunger 34 together with the armature 33 forms the first elastic body 34b. It descends while compressing, and the sphere 34a is seated on the first valve seat surface 36c to close the main orifice 36a. In this state, oil is discharged from the hydraulic brake 20 side through the NC-type solenoid valve 40 which is opened, thereby lowering the braking pressure and preventing sliding from the road surface. At this time, the oil escaping from the hydraulic brake 20 is temporarily stored in the low pressure accumulator 50.

Next, the braking pressure boost mode will be described. If the braking pressure decompression state described above is long lasting or the vehicle is moved to a place where the friction coefficient of the road surface is high, the braking pressure in the hydraulic brake 20 may be generated in the vehicle tire and the road surface than the braking pressure can be braked. As the friction force increases, the vehicle braking efficiency decreases. The ECU determines this situation based on a signal input from each wheel sensor (not shown), and drives the motor 60 to operate the pump 61 to increase the braking pressure in the hydraulic brake 20. Accordingly, when the braking pressure decompression operation is performed, the oil stored in the low pressure accumulator 50 is pressurized and supplied to the high pressure accumulator 70, and as shown in FIG. 4, the NO type solenoid valve 30 which is opened is opened. By transmitting to the hydraulic brake 20 through it to increase the braking hydraulic pressure.

The braking pressure holding mode is as follows. In the ABS control, the pressure in the hydraulic brake 20 reaches the optimum pressure for generating the optimum braking force, or in order to prevent the resonance phenomenon of the vehicle derived from the ABS control, an operating state for maintaining the pressure in a constant state is necessary. Pressure maintenance operation is performed.

This braking pressure maintenance mode is to prevent the pressure change in the hydraulic brake 20, and closes the hydraulic transmission by closing the NO-type solenoid valve 30 of the hydraulic brake 20 side to maintain the pressure. Therefore, the oil pressure discharged through the high pressure accumulator 70 by the pump 61 is transmitted to the master cylinder 10 side.

At this time, a substantial oil pressure discharged from the pump 61 side is applied upstream of the main orifice 36a of the closed-type NO solenoid valve 30, that is, inside the inlet 37c of the movable piston 37. As shown in FIG. 6, when the upstream side and the downstream side of the main orifice 36a are greater than or equal to a predetermined pressure difference (more than 13 bar in this embodiment), the movable piston 37 moves the second elastic body 38. It rises while compressing, and by this operation, the third valve seat surface 37f is seated on the second valve seat surface 36d. At this time, the upper part of the main orifice 36a, that is, the first valve seat surface 36c is closed by the sphere 34a of the plunger 34, and the lower part of the main orifice 36a is connected to the auxiliary orifice 37e. Communicating.

When the braking pressure boosting mode is again performed in the braking pressure maintaining mode, power supply to the NO type solenoid valve 30 is stopped, and as shown in FIG. 7, the plunger 34 is formed by the first elastic body 34b. Goes up. As the plunger 34 is raised and the main orifice 36a is opened, the oil inside the movable piston 37 inlet 37c is transferred to the hydraulic brake 20 side through the main orifice 36a and the outlet 31b to brake the pressure. It rises. At this time, although a considerable pressure difference is formed on the upstream side and the downstream side of the main orifice 36a, the initial hydraulic pressure transfer process is made stable in the direction of the arrow through the auxiliary orifice 37e having a relatively small diameter.

When the pressure difference between the upstream side and the downstream side of the main orifice 36a is eliminated due to the continuous hydraulic transmission, the movable piston 37 is lowered by the elastic restoring force of the second elastic body 38 and the second valve seat surface 36d The third valve seat surface 37f is spaced apart from the above, whereby the hydraulic pressure is smoothly transferred to the main orifice 36a through the branch flow passage 37d.

As a result, when the boosting mode is performed again after the braking pressure holding mode, first, the braking pressure is stably transmitted through the auxiliary orifice 37e and the main orifice 36a, whereby the boundary between the upstream side and the downstream side of the main orifice 36a. No hydraulic shock is generated from above and the braking action is also stable.

As described in detail above, according to the NO type solenoid valve for the anti-lock brake system according to the present invention, the braking hydraulic pressure transmitted from the master cylinder during the normal braking action is provided through the branch flow path formed on the movable piston and the main orifice formed on the valve seat. It delivers smoothly and improves braking response.When braking hydraulic pressure is controlled by ABS control, the braking hydraulic pressure is gradually increased through the auxiliary orifice and main orifice formed on the movable piston, so that the noise is effectively prevented and the braking action is performed. It also has the advantage of being stable.

Claims (5)

An outlet 31b associated with the hydraulic brake 20 side and a normal accommodating portion 31a are provided at one end inserted into and coupled to the bore 81 of the modulator block 80 and a sleeve 35 is mounted at the other end thereof. Valve seat 36, the sleeve is fitted into the housing 31, the receiving portion 31a of the valve housing 31, the main orifice 36a is provided in the upper center portion and the hydraulic chamber 36b is formed in the lower side of the valve housing 31, the sleeve The armature 33, which is built in the 35 and moves up and down by the solenoid 32, interlocks with the armature 33 and penetrates the valve housing 31 in the axial direction to open and close the main orifice 36a. A plunger 34 having a sphere 34a at the tip to elastically support the plunger 34 so that the main orifice 36a is normally kept open between the plunger 34 and the valve seat 36. The first elastic body 34b and one end 37a disposed in the hydraulic chamber 36b of the valve seat 6 A 37b is slidably disposed at the bottom of the bore 81 of the modulator block 80, and an inlet 37c associated with the master cylinder 10 side is provided therein, and the main orifice (37a) is provided at the center of one end 37a. The valve housing so that the main orifice (36a) and the auxiliary orifice (37e) is normally spaced apart by elastically supporting the movable piston (37) having the auxiliary orifice (37e) and the movable piston (37e) in association with 36a). A NO type solenoid valve for an anti-lock brake system, comprising: a second elastic body (38) disposed between the (31) and the movable piston (37). The method of claim 1, The movable piston 37 has an O-ring (37g) provided on the outer periphery of one end (37a) and a lip seal (37h) provided on the outer periphery of the other end (37b), At the center of one end 37a of the movable piston 37, a pair of branching passages 37d provided to branch so that the upper portion of the inlet 37c communicates with the hydraulic chamber 36b, and in the braking pressure holding mode of ABS, When the movable piston 37 rises due to a predetermined pressure difference between the inlet 37c and the outlet 31b by the closing operation of the main orifice 36a through the sphere 34a, the main orifice ( NO-type solenoid valve for an anti-lock brake system, characterized in that the valve seat surface 37f is formed with a curvature surface to close the lower portion of 36a) and the auxiliary orifice 37e is provided in communication with the inlet 37c. . The method of claim 1, The auxiliary orifice (37e) is a NO-type solenoid valve for an anti-lock brake system, characterized in that the diameter is formed smaller than the main orifice (36a). The method of claim 1, The bottom of the movable piston 37 extends into the inlet 37c to guide the oil supplied from the master cylinder 10 side to the hydraulic chamber 36b, and has a hollow guide portion 39a. And a hydraulic pressure guide member (39) having an outward flange (39b) whose diameter is extended to be seated at the bottom of the bore (81) of the modulator block (80). The method of claim 4, wherein NO type solenoid valve for an anti-lock brake system, characterized in that a filter (39c) is provided at the bottom of the outward flange (39b) of the hydraulic guide member (39).