KR20000035376A - Solenoid valve for anti-lock brake system - Google Patents

Abstract

PURPOSE: A solenoid valve for an anti-lock brake system is provided to vary the flux of oil upon slip brake. CONSTITUTION: When the increase of a brake force is demanded as the temporary increase of friction force of the surface in a slip control state, a plunger(140) is increased in a state that a piston(200) is fixed so that a fixing orifice(320) is opened. The compressed oil flowed in an entrance channel(300) passes through the fixing orifice(320) and a variable orifice(340) and is transmitted to a wheel cylinder via an exit channel(310). The slip is regulated with a brake force demanded in the wheel cylinder by the decompression reaction of the variable orifice and the opening/closing action of the plunger. In this state, when the brake pressure of a master cylinder is released, the oil is sent to the entrance channel through a gap between a bore(101) of a modulator(100) and a piston and a slot(161). Thereby, the brake force is quickly released.

Description

Solenoid valve for anti-lock brake system {SOLENOID VALVE FOR ANTI-LOCK BRAKE SYSTEM}

The present invention relates to an anti-lock brake system, and more particularly, to a normal open solenoid valve for an anti-lock brake system that can exhibit more efficient braking performance by varying the amount of oil supplied during slip control.

In general, the anti-lock brake system includes a wheel cylinder that is installed on a wheel of a vehicle to generate a braking force by hydraulic pressure, a power booster and a master cylinder that forms a braking hydraulic pressure and transmits it to the wheel cylinder, a modulator and an ECU that controls the braking hydraulic pressure. It consists of controlling braking force.

The modulator is equipped with a normally open solenoid valve and a normally closed solenoid valve for controlling the supply of oil.

The conventional normal open solenoid valve used in the anti-lock brake system is always open during normal braking, so that the hydraulic pressure generated from the master cylinder can be transmitted to each wheel cylinder without decompression. There is an intermittent opening and closing of the valve functions to control the braking force by adjusting the flow of oil.

The conventional normal open solenoid valve of the related art regulates the flow rate by restricting the flow of oil by simply opening and closing the plunger, so that the amount of oil passing through the valve during slip control is the flow rate of the oil during normal braking. Becomes the same as

Therefore, when adopting such a conventional solenoid valve, it is difficult to precisely control the flow rate of the hydraulic pressure can not perform accurate slip control, water hammering by the pulsation of the oil according to the opening and closing operation of the plunger of the valve (water Not only does it cause noise, but also worsens the durability of the parts.

In order to solve these problems, normally open solenoid valves have been developed for slip control to reduce the amount of oil supplied to the wheel cylinder according to the slip ratio, and to reduce the pulsation of oil. have. For example, as shown in FIG. 1, US Patent No. 5,647,644 discloses a normally open solenoid valve for an anti-lock brake system for achieving the above effect. This solenoid valve is provided with the valve seat 23, the magnetic core 21, the plunger 22, and the piston 24 which are installed in the valve housing 20 installed in the modulator block 10. As shown in FIG. The valve seat 23 has a through hole formed therein and is press-fitted to the lower portion of the valve housing 20, and the magnetic core 21 is installed at the upper portion of the valve housing 20. The plunger 22 is installed through the magnetic core 21, and a lower end thereof is disposed adjacent to an upper end of the valve seat 23. And the piston 24 is arrange | positioned at the outer periphery of the valve seat 23 in the state pushed downward by the spring 25. As shown in FIG. The normal open solenoid valve is configured to form two orifices, one of which is a fixed orifice 30 provided at the upper end of the valve seat 23 formed in a hollow, and the other is the piston 24 in the slip control the magnetic core It is a variable orifice 40 formed by a slot 26 formed in the upper end of the piston 24 when it contacts 21.

Meanwhile, an auxiliary passage 31 through which oil flows between the valve seat 23 and the valve housing 20 is formed at one side of the lower end of the valve seat 23. The oil introduced therethrough flows through the auxiliary flow passage 31 to move the piston 24 upward. In addition, a step portion 23a is formed at the other end of the lower end of the valve seat 23 so as to press-mold and fix the valve seat 23 in the valve housing 20.

In the conventional normal open solenoid valve as described above, during normal braking, the plunger 22 is kept upward and the piston 24 is kept downward, so that oil flows into the inlet portion 27 of the valve and is fixed open. Discharged through the orifice 30 to the outlet 28 of the valve.

On the other hand, during slip control, the plunger 22 moves downward to close the fixed orifice 30, and oil introduced through the inlet part 27 flows through the auxiliary flow path 31 to raise the piston 24. To be in contact with the magnetic core 21. Then, when the plunger 22 moves upward, the hydraulic pressure generated in the master cylinder passes through the variable orifice 40 formed by the slot 26 of the piston 24 in contact with the magnetic core 21 and the wheels. Delivered to the cylinder.

When the braking force is released, the oil of the wheel cylinder is first returned to the master cylinder through the return passage 29 formed in the valve housing 20 so as to connect the inlet portion 27 and the outlet portion 28 of the oil, and then the plunger ( 22) moves upward and the valve is restored to the open state.

However, in the conventional normal open solenoid valve as described above, an outer side of the valve seat has an auxiliary flow path for moving the piston upward by moving oil between the valve seat and the valve housing during slip control, and the valve seat has a valve housing. Since the stepped portion is formed to be fixed therein, and furthermore, the distance between the outer side surface of the auxiliary flow channel side valve seat and the valve housing must be constantly maintained, there is a problem that the manufacturing process and the assembly process of the valve seat are quite difficult. .

In addition, the conventional solenoid valve has a problem that the overall size of the valve is increased because the valve housing for accommodating the magnetic core, the valve seat, the piston, the oil flow path must be provided separately.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a solenoid valve for an anti-lock brake system capable of varying the flow rate of oil during slip braking.

Another object of the present invention is to provide a solenoid valve for an anti-lock brake system, which is simple in structure and easy to manufacture by forming a double orifice with oil flow paths by a valve seat and a piston.

1 is a cross-sectional view of a conventional solenoid valve for an anti-lock brake system.

2 is a cross-sectional view of the solenoid valve according to the first embodiment of the present invention in an open state for normal braking.

3 is a cross-sectional view of the solenoid valve according to the first embodiment of the present invention in the process of closing for slip control.

4 is a cross-sectional view of the solenoid valve according to the first embodiment of the present invention in a state in which closing is completed for slip control.

Fig. 5 is a sectional view of the solenoid valve according to the first embodiment of the present invention in a partially open state for slip control.

Fig. 6 is a sectional view of a solenoid valve according to a second embodiment of the present invention in an open state for normal braking.

7 is a sectional view of a solenoid valve according to a second embodiment of the present invention in the process of closing for slip control.

Fig. 8 is a sectional view of the solenoid valve according to the second embodiment of the present invention in the closed state for slip control.

Fig. 9 is a sectional view of a solenoid valve according to a second embodiment of the present invention in a partially open state for slip control.

Explanation of symbols on the main parts of the drawings

130: magnetic core 140: plunger 150: valve seat

200: piston 300: inlet flow passage 310: outlet flow passage

320: fixed orifice 340: variable orifice 400: lip seal

In order to realize the above object, the solenoid valve according to the present invention has a magnetic core, a plunger, a piston and a valve seat, and is installed in a modulator of an anti-lock brake system.

The magnetic core is installed in a bore formed in the modulator, and a plunger hole is formed through the vertically.

The valve seat is disposed in the bore of the modulator at the bottom of the magnetic core, and a fixed orifice is formed at an intermediate point therein, the lower portion of the fixed orifice forms an inlet flow passage and the upper portion of the valve flow passage.

The plunger is installed in the plunger hole so as to be movable, and at the bottom thereof, a ball for opening and closing the top of the fixed orifice is mounted.

The piston is installed on the outer periphery of the valve seat so as to be movable. The variable orifice is provided on the upper side of the valve seat, and has a first protruding jaw formed in the middle of the outer periphery and a length smaller than the first protruding jaw at the bottom thereof. It has a second projection step formed. The first projection is located close to the inner peripheral surface of the bore of the modulator, the second projection is located at the lower end of the bore.

A spring is disposed between the first protrusion of the piston and the magnetic core to push the piston in the direction of opening the outlet passage, and oil flows through the piston into the outlet passage between the first protrusion and the second protrusion of the piston. The lip seal which prevents it is installed.

As a first embodiment of the present invention, the valve seat is fixed to the lower end of the bore of the modulator, the upper end of the valve seat in this state to form an outlet of the oil by being spaced apart from the lower end of the magnetic core.

In this first embodiment, a ring-shaped support member is provided between the second protruding jaw of the piston and the lower end surface of the bore of the modulator. In addition, the lower end of the valve seat is formed with side holes and one side of the support member is cut to form a slot so that the inlet flow path and the lip seal installed on the outer periphery of the piston communicate with each other.

As a second embodiment of the present invention, the valve seat is fixed to the lower end of the magnetic core, the upper end of the valve seat is provided with an outlet hole communicating with the outlet flow path.

In this second embodiment, the valve seat is spaced apart from the lower end surface of the bore of the modulator in a state of being fixed to the magnetic core so as to form a gap. The gap and the slot formed by being cut in one side of the supporting member are in communication with each other between the inlet flow passage and the lip seal provided on the outer periphery of the piston.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 shows a solenoid valve according to a first embodiment of the present invention, which is maintained in an open state during normal braking. The normal open solenoid valve includes a magnetic core 130, a plunger 140, a valve seat 150, and a piston 200, so that the valve seat 150 is formed on the modulator 100. At the lower end of the magnetic core 130 is fixed to the upper end of the bore 101 is installed in the modulator 100. The sleeve 110 having the armature 112 embedded therein is attached to the magnetic core 130, and the yoke 120 having the coil 115 embedded in the outer circumference of the upper portion of the magnetic core 130 protruding to the outside. Is attached. The plunger 140 is attached to the lower end of the armature 112, the armature 112 is disposed to be spaced apart from the magnetic core 130 in a normal open state of the valve so that the plunger 140 can move in the vertical direction. .

A plunger hole 131 is formed vertically in the magnetic core 130 to embed the plunger 140. A plunger 140 having an upper end attached to the armature 112 is disposed in the plunger hole 131. It is embedded and is disposed near the fixed orifice 320 formed in the valve seat 150. In the normal open state of the valve, the upper end of the plunger 140 is arranged to maintain a spaced distance from the upper end of the fixed orifice 320 in the state attached to the armature 112. The lower end of the plunger 140 is mounted with a ball 141 for closing the valve by closing the upper end of the fixed orifice 320 during slip control.

The valve seat 150 has a hollow cylinder shape, and a lower end thereof is fixed to a lower end of the bore 101 of the modulator 100, and an upper end thereof is spaced apart from the lower end of the magnetic core 130 by a predetermined distance. At the intermediate point inside the valve seat 150, a fixed orifice 320 having a suitable cross-sectional area is provided. The lower portion of the fixed orifice 320 forms an inlet flow path 300 for introducing the hydraulic oil from the master cylinder (not shown), and the upper portion of the fixed orifice 320 discharges the hydraulic oil to the wheel cylinder (not shown) with the valve open. It is in communication with the outlet passage 310 for. A spring 142 is disposed between the plunger 140 and the valve seat 150 to push the plunger 140 upward.

As described above, the solenoid valve according to the present invention does not require a valve body according to the present invention due to the structure in which flow paths for flowing oil are formed by the valve seat 150 in the bore 101 of the modulator 100.

The piston 200 is arranged to be movable between the outer circumference of the valve seat 150 and the inner circumference of the bore 101 of the modulator 100. The piston 200 has a first protruding jaw 201 extending outward from an intermediate point of the piston 200 so as to form a fine gap with the inner periphery of the bore 101 and than the first protruding jaw 201. The second protrusion 202 is formed to extend outward from the lower end of the piston 200 to have a short length. In addition, a variable orifice 340 is formed in the piston 200 to control the flow rate and pressure of the oil in a state in which the piston 200 rises during the slip control to close the outlet passage 310. The variable orifice 340 consists of a hole having a suitable diameter formed on one side of the upper end of the piston 200. A spring 220 is disposed between the first protruding jaw 201 and the magnetic core 130 of the piston 200 to push the piston 200 downward.

A lip seal 400 is installed between the first protrusion 201 and the second protrusion 202 of the piston 200 to prevent flow in the outlet direction of the oil, and the second protrusion of the piston 200 is provided. A ring-shaped support member 160 is installed between the 202 and the lower surface of the bore 101 of the modulator 100. One side of the supporting member 160 is cut so that the slot 161 is formed, and the side hole 151 is also formed at the lower end of the valve seat 150 corresponding to the slot 161. Therefore, the lip seal 400 installed at the outer circumference of the inlet flow path 300 and the piston 200 is in communication with each other through the minute side hole 151 and the slot 161. However, the lip seal 400 allows the flow from the exit direction to the inlet direction, while the flow in the opposite direction is prevented.

Inside the outer circumference of the valve seat 150, an O-ring 180 is installed to prevent oil from leaking between the valve seat 150 and the piston 200 at the same time.

Hereinafter, the operation of the normal open solenoid valve according to the first embodiment of the present invention having the above structure will be described.

Figure 2 shows a solenoid valve that is maintained in the normal open state during normal braking. In this state, the plunger 140 and the armature 112 are placed on the inner top of the sleeve 110 so that the ball 141 attached to the bottom of the plunger 140 keeps the fixed orifice 320 open. In addition, the piston 200 is placed in contact with the support member 160 by the elastic force of the spring 220 so that the outlet passage 310 is connected to the inlet passage 300 through the fixed orifice 320 to the valve. Keep it open. Therefore, the pressure oil generated in the master cylinder is transferred to the wheel cylinder through the inlet flow path 300 and the outlet flow path 310 to exert a normal braking force. At this time, although the inlet flow path 300 is in communication with the space where the lip seal 400 is located, the side surface 151 and the slot 161 formed on the side of the valve seat 150 and the supporting member 160, Since the hole 151 and the slot 161 are formed to have a relatively small size compared to the fixed orifice 320, and the flow of oil in the outlet direction is prevented by the lip seal 400, the oil is the outlet flow path 310 Will flow only.

When slip occurs in the wheel in the normal braking mode as described above, the braking force is switched to the slip control mode in which the braking force is reduced according to the frictional force of the road surface. Accordingly, when the plunger 140 descends and the ball 141 blocks the upper end of the fixed orifice 320 so that communication between the inlet flow passage 300 and the outlet flow passage 310 is blocked, the pressure oil is shown in FIG. 3. The lip seal 400 is transferred to the space where the lip seal 400 passes through the side hole 151 of the valve seat 150 and the slot 161 of the support member 160. In this state, the lip seal 400 prevents the oil from flowing into the outlet passage 310 along the outer circumference of the piston 200 in the upward direction, that is, a spring between the inlet passage 300 and the outlet passage 310. The pressure difference that overcomes the elastic force of the 220 is generated so that the piston 200 moves upward.

4 illustrates a state in which the switch to the slip control mode is completed and the piston 200 contacts the lower end of the magnetic core 130 by the above-described action. In this state, the variable orifice 340 formed on the upper portion of the piston 200 communicates the outlet side and the outlet passage 310 of the fixed orifice 320 formed on the valve seat 150 but is fixed by the plunger 140. Since 320 is closed, the hydraulic pressure of the master cylinder is not transmitted to the wheel cylinder so that braking force is not generated.

In this slip control state, when an increase in braking force is required according to a temporary increase in the frictional force of the road surface, as shown in FIG. 5, the plunger 140 is raised in a state where the piston 200 is fixed and the fixed orifice 320 is opened. Will be. Therefore, the pressurized oil introduced into the inlet flow passage 300 passes through the fixed orifice 320 and the variable orifice 340 and is transferred to the wheel cylinder via the outlet flow passage 310. Therefore, by the decompression action of the variable orifice 340 and the opening and closing operation of the plunger 140, it is possible to adjust the braking force required by the wheel cylinder during slip control.

When the braking pressure of the master cylinder is released in this state, the oil is sent to the inlet flow path 300 through the gap between the bore 101 and the piston 200 of the modulator 100 and the side hole 151 and the slot 161. The braking force is quickly released. Thereafter, the plunger 140 is raised to open the fixed orifice 320, and at the same time, the piston 200 descends in response to the release of the braking pressure, so that the outlet passage 310 and the inlet passage 300 communicate with each other as shown in FIG. 2. It will return to normal braking state.

6 to 9 are views corresponding to FIGS. 2 to 5 respectively, which are shown for explanation of the first embodiment described above, and show a second embodiment of a normal open solenoid valve according to the present invention. That is, FIG. 6 is a view corresponding to FIG. 2 of the first embodiment, showing a solenoid valve according to the second embodiment in an open state for normal braking, and FIG. 7 corresponding to FIG. 4 shows the solenoid valve of the second embodiment in the process of closing, FIG. 8 corresponding to FIG. 4 shows the solenoid valve of the second embodiment in the closed state for slip control, and FIG. 9 corresponding to FIG. The solenoid valve of the second embodiment is shown in a partially open state for control. As can be seen from the figures, the solenoid valve according to the second embodiment of the valve seat 150 is fixed to the lower surface of the magnetic core 130, the outlet passage (top) on both sides of the upper portion of the valve seat 150 An exit hole 155 communicating with 310 is provided. In addition, the valve seat 150 is spaced apart from the bottom surface of the bore 101 of the modulator 100 by being fixed to the magnetic core 130 to form a gap 152. The width of the gap 152 is made equal to the width of the support member 160 installed between the piston 200 and the bottom surface of the bore 101. Therefore, the space where the lip seal 400 is installed is in communication with the inlet flow path 300 through the slot 161 formed in the gap 152 and the support member 160.

Except for the above structure, the solenoid valve of the second embodiment is configured in the same way as the solenoid valve of the first embodiment, and the operation of the valve is made the same. Therefore, since the configuration and operation of the solenoid valve of the second embodiment can refer to the first embodiment, further description thereof will be omitted.

As described above, the normal open solenoid valve according to the present invention has a fixed orifice and a variable orifice that can supply the pressure by reducing the pressure of the oil, so that it is easy to adjust the braking force to perform accurate slip control. have. Accordingly, it is possible to increase the reliability of the product. In addition, the double orifice structure can prevent a sudden change in pressure on the oil flow path, thereby preventing water hammering. Accordingly, it is possible to reduce operating noise and to prevent damage to components due to impact.

In addition, the normal open solenoid valve according to the present invention has a simple structure and easy to manufacture by forming the oil passages and orifices using the valve seat and the piston.

Claims (10)

In an anti-lock brake system having a modulator and a solenoid valve, The solenoid valve has a magnetic core 130, a plunger 140, a piston 200 and a valve seat 150, The magnetic core 130 is installed in a bore (101) formed in the modulator 100, the plunger hole 131 is formed through the vertically therein, The valve seat 150 is disposed in the bore 101 of the modulator 100 at a lower portion of the magnetic core 130, and a fixed orifice 320 is formed at an intermediate point therein. The lower portion of the 320 forms the inlet flow path 300 and the upper portion of the outlet flow path 310. The plunger 140 is installed in the plunger hole 131 so as to be movable, and the bottom thereof is equipped with a ball 141 for opening and closing the upper end of the fixed orifice 320, The piston 200 is installed on the outer periphery of the valve seat 150 so that the variable orifice (340) formed through the side is provided on the upper periphery of the anti-lock brake system solenoid valve. The method of claim 1, The piston 200 has a first protrusion 201 formed in the middle portion of the outer periphery and a second protrusion 202 formed at a lower length than the first protrusion 201 in the lower end thereof. The first projection jaw 201 is located close to the inner peripheral surface of the bore 101 of the modulator 100, the second projection jaw 202 is an anti-lock, characterized in that located on the lower end of the bore 101 Solenoid valve for brake system. The method of claim 2, A spring 220 is disposed between the first protrusion 201 and the magnetic core 130 of the piston 200 to push the piston 200 in the direction of opening the outlet passage 310. Solenoid valve for anti-lock brake system. The method of claim 2, An anti-lock brake system is installed between the first protrusion 201 and the second protrusion 202 of the piston 200 to prevent the oil from flowing in the direction of the outlet passage 310. Solenoid valve. The method of claim 4, wherein The lower end of the valve seat 150 is fixed to the lower end of the bore 101 of the modulator 100. In this state, the upper end of the valve seat 150 is spaced apart from the lower end of the magnetic core 130 by a predetermined distance. A solenoid valve for an anti-lock brake system, thereby forming an outlet of oil. The method of claim 5, A solenoid valve for an anti-lock brake system, characterized in that a ring-shaped support member 160 is installed between the second protrusion 202 of the piston 200 and the lower surface of the bore 101 of the modulator 100. . The method of claim 6, The lower end of the valve seat 150 is formed with a side hole 151, one side of the support member 160 is cut off to form a slot 161 of the inlet flow path 300 and the piston 200 Solenoid valve for the anti-lock brake system, characterized in that the lip seal 400 installed on the outer periphery is in communication with each other. The method of claim 4, wherein The valve seat 150 is fixed to the lower end of the magnetic core 130, the upper end of the valve seat 150, the outlet hole 155 in communication with the outlet flow path 310 is provided that A solenoid valve for an anti-lock brake system. The method of claim 8, A solenoid valve for an anti-lock brake system, characterized in that a ring-shaped support member 160 is installed between the second protrusion 202 of the piston 200 and the lower surface of the bore 101 of the modulator 100. . The method of claim 9, The valve seat 150 is spaced apart from the lower surface of the bore 101 of the modulator 100 by a predetermined interval in a fixed state to the magnetic core 130, the gap 152 is formed, the supporting member ( One side of the 160 is cut to form a slot 161, the anti-lock brake system, characterized in that the inlet passage 300 and the lip seal 400 installed on the outer periphery of the piston 200 is in communication with each other Solenoid valve.