JPH11218254A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent noise generated periodically on an operation of a solenoid valve by absorbing noise generated when a shaft collides with a valve sheet by oil around an inlet hole of the valve sheet, and absorbing noise generated when a movable iron core collides with a shim or a fixed iron core in an oil sump. SOLUTION: A cap 24 is provided with a base part 25 fitted to a cylindrical part 23 and an umbrella part 27 having a first space 26 for an oil sump, the cap 24 is erected from a diameter direction inner side from an outer peripheral edge of the base part 25, and a window part 28 for opening the first space 26 outward is drilled on the cap 24. The window part 28 is provided with a second space 29 which is arranged on the base part 25 and which is opened downward, and is communicated with the first space 26 through a passage 30 cut in an axial direction. Operating oil is jumped up to the first space 26, and however, most of the operating oil flows out to an outlet hole 14. A part of the operating oil jumped up to the first space 26 is accumulated in the second space 29, and the first space 26 is communicated with an outside through the operating oil in the second space 29. Noise generated when a movable iron core 6 collides with a shim 22 or a fixed iron core 3 is absorbed by the operating oil in the second space 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve for reducing operating noise.

[0002]

2. Description of the Related Art Many electromagnetic valves are used in a hydraulic circuit of an automatic transmission of an automobile, and the electromagnetic valve controls the hydraulic pressure in the hydraulic circuit by pulse width modulation control. FIG. 5 shows an example of a conventional solenoid valve. The solenoid valve 1 has a cylindrical housing 2 made of a magnetic material, a fixed iron core 3 disposed therein, a bobbin 5 of a synthetic resin material around which a coil 4 is wound, and a movable movable in series with the fixed iron core 3. It has an iron core 6, a magnetic holder 7 disposed between the movable iron core 6 and the bobbin 5, and a valve seat 8 supported by the magnetic holder 7.

The solenoid valve 1 has an inflow pipe 10 that defines a fluid passage leading to an inlet hole 9 of a valve seat 8.
Is connected to the hydraulic pressure source 1 via the filter 11 and the fixed throttle 12.
3 is connected. The outlet hole 14 provided in the magnetic holder 7 is
The inlet hole 9 can be communicated with a discharge port 15 provided in the housing 1. The fixed core 3 and the movable core 6 have a central hole 16 concentric with the center of the housing 2.
A shaft 17 for opening and closing the inlet hole 9 provided in the valve seat 8 is inserted into 6, and makes the shaft 17 reciprocally movable in the axial direction together with the movable iron core 6. The tip of the shaft 17 is seated on the valve seat 8 by the spring 18 by the spring 18, and the inlet hole 9 is always closed. Spring 1
The biasing force 8 is adjusted by the amount of screwing of the adjusting screw 19 into the fixed iron core 3. Reference numeral 20 denotes a non-magnetic spacer, which magnetically insulates the magnetic holder 7 from the fixed core 3. Reference numeral 21 denotes a bush, which includes a movable iron core 6 and a shaft 1 integrated therewith.
Guide the movement of 7.

In order to reduce the influence of residual magnetism between the fixed core 3 and the movable core 6, the fixed core 3 and the spacer 20
The movement of the movable iron core 6 in the axial direction is stopped by the shim 22. Bush 21 from exit hole 14
Hydraulic oil that has entered between the shaft and the shaft 17 is discharged outside through the central hole 16 and the central hole of the adjusting screw 19 between the movable iron core 6 and the spacer 20.

[0005] Hydraulic oil from a hydraulic source 13 flows into the inflow pipe 10 through the fixed throttle 12. Since the urging force of the spring 18 causes the distal end surface of the shaft 17 to be seated on the valve seat 8, the inlet hole 9 is closed by the shaft 17, and there is no outflow of hydraulic oil from the inlet hole 9. When a current is applied to the coil 4,
A magnetic flux is generated so as to surround the coil 4 around the housing 1, the movable core 6, the fixed core 3, and the magnetic holder 7 around the coil 4, and the magnetic flux generates an electromagnetic attraction force between the fixed core 3 and the movable core 6. generate. By this electromagnetic attraction force, the movable iron core 6 is attracted to the fixed iron core 3 side against the urging force of the spring 18, the shaft 17 opens the inlet hole 9, and the hydraulic oil flows from the inlet hole 9 through the outlet hole 14. And is discharged from the discharge port 15. The axial movement of the movable iron core 6 is shim 2
Stopped by 2.

In the pulse width modulation control, energizing the coil 4
The de-energization is repeated several tens of times per second. When the power is supplied, the movable iron core 6 for opening the inlet hole 9 by the electromagnetic attraction force as described above is made. To close the inlet hole 9. By extending the energization time to the coil 4, the pressure of the hydraulic oil in the hydraulic circuit leading to the inflow pipe 10 can be reduced.

[0007]

Since abnormal noises are generated periodically during the operation of the above-mentioned solenoid valve, an object of the present invention is to eliminate the abnormal noises.

[0008]

The inventor of the present invention considers that the above-mentioned generation of the abnormal noise is caused by the sound of the shaft hitting the valve seat and the sound of the movable core colliding with the shim or the fixed core.
When a sound absorbing material such as rubber was arranged on a valve seat or a shim, it was found to be impractical due to problems such as durability of the sound absorbing material in hydraulic oil and separation from the valve seat.

In order to further analyze the generation of abnormal noise, the present inventor has found that the abnormal noise is generated when the energization of the coil is stopped in response to the collision noise of the shaft against the valve seat generated when the coil is energized. It is presumed that the hitting sound of the movable iron core that hits the shim or the fixed iron core is louder, and it is presumed that it is composed of this hitting sound.An oil reservoir is created in the center hole of the adjusting screw, An attempt was made to release abnormal noise to the outside, but this was found to be effective in reducing the operating noise leaking to the outside of the solenoid valve. Therefore, the sound of collision between the shaft and the valve seat is absorbed by oil around the inlet hole of the valve seat, and the sound of collision between the movable iron core and the shim or fixed iron core is absorbed by a newly created oil reservoir around the adjustment screw. The inventor makes a proposal.

Specifically, in order to solve the above-mentioned problems, the present invention provides a fixed core having a center through hole having a center coinciding with the center of a housing, and a movable core arranged in series with the fixed core. An iron core, a coil wound on a bobbin of a non-magnetic material and moving the movable iron core in the axial direction when energized, and a valve seat having an inlet hole that opens and closes according to the axial movement of the movable iron core, An electromagnetic valve, wherein the fixed iron core has a cap with an oil reservoir, and abnormal noise transmitted through a central through-hole of the fixed iron core is released to the outside through hydraulic oil in the oil reservoir. I do.

[0011]

1 and 3 show an embodiment of the present invention. Since the basic configuration of the solenoid valve shown in FIGS. 1 and 3 is the same as that of the conventional example shown in FIG. 5, the same parts are denoted by the same reference numerals and description thereof is omitted. In the example shown in FIG. 1, the cap 2 is attached to the fixed iron core 3 so as to be located around the adjustment screw 19.
4 is fixed.

The cap 24 has a cylindrical base portion 25 fitted into the upwardly directed cylindrical portion 23 of the fixed iron core 3, and a first space 26 for an oil sump inside the base portion 25 integrated with the base portion 25.
And an umbrella portion 27 for defining the base portion 2
5 rises radially inward from the outer peripheral edge. Three or four first spaces 26 at appropriate locations in the base portion 25, preferably at equal intervals
The window 28 that opens the outside to the outside can be formed. The window portion 28 has a downwardly opened second space 29 provided in the base portion 25, and the second space 29 communicates with the first space 26 via a passage 30 cut in the axial direction.

The hydraulic oil passing through the entrance / exit holes 9 and 14 jumps toward the first space 26 through the gap between the shaft 17 and the spacer 21 and the gap between the movable iron core 6 and the spacer 20, but most of the oil flows. The hydraulic oil flows out through the same gap toward the outlet hole 14. A part of the hydraulic oil that has risen from the central hole 16 to the first space 26 accumulates in the second space 29, and makes the first space 26 communicate with the outside via the hydraulic oil in the second space 29. As a result, the impact sound of the movable iron core 6 entering the first space 26 against the shim 22 or the fixed iron core 3 is absorbed by the hydraulic oil in the second space 29. Hydraulic oil may be put in the second space 29 in advance.

FIG. 3 shows an example in which the solenoid valve is installed with its axis centered in the horizontal direction. The cap 31 has a cap 31 fitted to the cylindrical portion 23, and the cap 31 has a top 32. The top portion 32 of the cylindrical body is stepped to form a step portion 33. The step portion 33 is provided with a window portion 34 opened toward the top portion 32. The first space 35 in the cap 31 communicates with the window 34 through a notch 36 in the axial direction. In FIG. 3, the solenoid valve is shown as being arranged vertically, but this example is actually used as a horizontal type rotated 90 degrees clockwise, the hydraulic oil fills the cut 36, and the shim 2 of the movable core 6 is
The sound of the collision with 2 or the fixed iron core 3 is absorbed by the hydraulic oil in the cut 36 and does not leak outside. The hydraulic oil comes up from the inlet hole 9 side, but it is preferable to put the hydraulic oil into the cut 36 in advance.

[Brief description of the drawings]

FIG. 1 is a sectional view of a solenoid valve according to an example of the present invention.

FIG. 2 is a perspective view of a cap.

FIG. 3 is a sectional view of a solenoid valve according to another example of the present invention.

FIG. 4 is a perspective view of another example of a cap.

FIG. 5 is a sectional view of a conventional solenoid valve.

[Explanation of symbols]

 2 Housing 3 Fixed core 4 Coil 5 Bobbin 6 Movable core 7 Magnetic holder 8 Valve seat 9 Inlet hole 10 Inflow pipe 14 Outlet hole 16 Central hole 17 Shaft 18 Coil 19 Adjustment screw 22 Shim 23 Tube part 24 Cap 26, 35 Space 29, 34 sump

Claims (4)

[Claims] 1. A fixed core having a center through hole having a center coinciding with the center of a housing, a movable core arranged in series with the fixed core, and a non-magnetic bobbin wound and energized. A coil for moving the movable iron core in the axial direction,
A valve seat having an inlet hole that opens and closes in accordance with the movement of the movable core in the axial direction, wherein the fixed core has a cap with an oil reservoir, and abnormal noise transmitted through a central through hole of the fixed core. Is discharged to the outside through hydraulic oil in an oil reservoir. 2. A cap having a cylindrical base with a top and a notch provided in at least one axial direction.
2. The solenoid valve according to claim 1, wherein the cut is open to the outside and has an oil reservoir. 3. The solenoid valve according to claim 2, wherein the oil reservoir of the cap is defined by a lower portion of the cut and a top surface of the fixed iron core. 4. The solenoid valve according to claim 2, wherein the top of the cap has a step, and a window provided in the step and opened to the outside and the cut is an oil reservoir.