JPH1140421A - Electromagnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnet by which damage to parts can be minimized by absorbing play at a tube body produced at the time of fitting of the electromagnet to a valve body or the like. SOLUTION: An electromagnet 1 comprises an outer case 3 and a tube body 4. The outer case 3 has a flange 3a at its front end and a rear wall 3c at its rear end. The tube body 4 comprises a bobbin 5 around which a coil 7 is wound, a fixed core 9 and a movable core 11 placed in the bobbin 5 and a yoke placed around the bobbin 5. The rear end of the bobbin 5 is covered with a rear wall 5a and the fixed core 9 is fitted to the closed end. A corrugated washer 15 is placed between the rear wall 3c of the outer case 3 and the rear wall 5a of the bobbin 5. A corrugated washer 35 is placed between the front end of the fixed core 9 and a valve body 40. Vertical play between the tube body 4 and the outer case 3 is absorbed by these washers 15 and 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnet having a fixed iron core and a movable iron core, wherein the movable iron core slides when a coil is excited.

[0002]

2. Description of the Related Art Conventionally, an electromagnet has a bobbin formed in a hollow shape, a magnetic coil wound around the bobbin, a fixed iron core disposed in the bobbin, and a sliding member which is close to and separated from the fixed iron core. A movable iron core to be moved. And
Generally, the movable core is operated so as to be attracted to the fixed core by excitation of the magnetic coil.

The electromagnet 20 shown in FIG. 3 is widely used as an oil immersion type especially for a hydraulic solenoid valve or the like. This electromagnet 20
A coil assembly 21; a tube assembly 26 fitted into the coil assembly 21;
And a nut 31 for fixing the tube assembly 26 and the coil assembly 21. The coil assembly 21 has a hollow bobbin 24 in which a magnetic coil 23 is wound in a hollow round outer case 22 and a yoke. The tube assembly 26 has a fixed iron core 27 and a movable iron core 28, and further has a pipe 29 for fitting the fixed iron core 27 and the movable iron core 28. I have. The pipe 29 is formed of a ring-shaped non-magnetic material, is inserted into the inner peripheral surface of the hollow portion of the bobbin 24, and has one end connected to the fixed core 2.
A movable iron core 28 that engages with and is welded to the inner core 7 and that approaches and separates from the fixed iron core 27 is slidably disposed on the inner peripheral surface.
A stopper 30 is welded to the other end of the pipe 29, and a nut 31 is screwed and attached to the stopper 30 in order to integrally fix the coil assembly 21 and the tube assembly 26.

The fixed iron core 27 has a through hole 27a including an oil passage through which a pin (not shown) is inserted along the central axis, and a male screw 27b formed at the outer periphery of the distal end portion. Attached to. An oil groove 28a for circulating oil is formed in one or both outer peripheral surfaces of the movable core 28 in the axial direction, and oil flowing from the fixed core 27 side circulates through the movable core 28 to the stopper 30 side. It had been. And a seal for preventing oil leakage was provided at a necessary place.

[0005]

However, as price competition intensifies, it becomes necessary to reduce costs.
Revisions have been made to simplify the structure and reduce the number of parts. In order to solve this problem, the present applicant has filed Japanese Patent Application No.
No. 161026, in particular, a rear end face of an outer case formed of a magnetic material is closed, a rear end face of a non-magnetic bobbin is closed, and a fixed iron core and a movable iron core are directly fitted in the bobbin. Proposing electromagnets. However, in this type of electromagnet, when the movable iron core is adsorbed by the fixed iron core and then returns, the movable iron core stops in a state of collision with the stopper of the bobbin. The impact due to the collision gives rise to a possibility that the electromagnet 1 may be damaged during long-term use of the electromagnet 1.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has an improved electromagnet having a simple structure in which the number of parts is reduced and cost is reduced so that damage to a bobbin and the like due to impact of a movable iron core is extremely reduced. It is an object to provide a manufactured electromagnet.

[0007]

An electromagnet according to the present invention has the following configuration to solve the above-mentioned problems. That is, a tube in which one end is opened and a coil is housed therein, and a tube in which the movable core is slidably disposed inside the outer case and a fixed core is fixedly disposed at the distal end. Body, the fixed core is fitted and held in an object to be mounted, and the movable core is an electromagnet that is attracted to the fixed core by excitation of the coil, and a rear end of the outer case and the tube body In the axial direction of the tube body, between the rear end portion, or between the rear end portion of the outer case and the rear end portion of the tube body, and between the front end surface of the fixed core and the attached object. An elastic member is provided to eliminate the generated play.

Preferably, the elastic member is a washer formed in a wavy shape.

More preferably, the tube body may include a bobbin wound around the coil and having a rear wall having a rear wall and closing.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the electromagnet 1 of the present embodiment
It has a round outer case 3 and a tube body 4 arranged in the outer case 3. The tube body 4 is
Including a bobbin 5, a coil 7 arranged to wind the bobbin 5, a fixed iron core 9 and a movable iron core 11 arranged in the bobbin 5, and a yoke 13 arranged around the bobbin 5. The outer case 3 is attached to the valve body 40 with the fixed iron core 9 fitted to the valve body 40.

The outer case 3 is made of a magnetic material, has a front end (lower part in FIG. 1) and an opening having a flange 3a to be attached to the valve body 40, and a rear part (upper part in FIG. 1) has a main body. 3b, it has a small diameter and is closed with a rear wall 3c, and is formed in a cylindrical shape as a whole.

The bobbin 5 is formed of a non-magnetic material in a cylindrical shape, and has a front end opened and a rear end closed with a rear wall 5a. A pair of coil storage walls 51 and 52 are formed on the outer peripheral surfaces of the front end portion and the intermediate portion of the bobbin 5 so as to be outwardly received in the outer case 3. The coil 7 is wound and stored. Further, the rear coil housing wall 52 and the gap 5 are provided on the rear end side.
b, a disk-shaped flange plate 53 is formed to be housed in the outer case 3, and a lead wire 7 a of the coil 7 is inserted into a gap 5 b formed between the coil housing wall 52 and the flange plate 53. Is accommodated, and a yoke 13 made of a magnetic material is disposed between the flange plate 53 and the rear end surface of the main body 3b of the outer case 3. Inside the rear wall 5a of the bobbin 5, a stopper portion 54 is formed inward, and the movable core 11 is connected to the stopper portion 54.
When the movable iron core 11 is
To reduce the bonding area.

Further, on the inner peripheral surface of the bobbin 5, a first fitting surface 55 for fitting with the fixed iron core 9 is formed on the front end side, and is connected to the first fitting surface 55 and is provided on the rear end side. A second fitting surface 56 that fits with the movable iron core 11 is formed. And the first
The fitting surface 55 is formed to have a larger diameter than the second fitting surface 56, and the fixed core 9 is positioned by the rear end surface of the fixed core 9 abutting the front end surface of the second fitting surface 56.

A plurality of slit-shaped oil grooves 57 are formed in the second fitting surface 56 of the bobbin 5 along the axial direction to form an oil passage. Only one oil groove may be formed, or a plurality of oil grooves may be formed at equal intervals. 2 between the rear wall 5a of the bobbin 5 and the small diameter rear wall 3c of the outer case 3.
As shown in (1), a wavy washer 15 having elasticity is arranged, and the bobbin 5 is pressed toward the valve body 40, thereby eliminating the axial play of the bobbin 5 in the outer case 3. The washer 15 is circular, has a hole at the center, and has an annular portion wavy in the radiation direction. In addition, since it can be arranged in a space corresponding to the thickness of the washer, it can be compact.

The fixed iron core 9 is fitted to the first fitting surface 55 of the bobbin 5 as described above, and its rear end surface has a concave portion 9a and abuts against the front end surface of the second fitting surface 56. Project forward from the coil housing wall 51 on the front end face of the bobbin 5 and are fitted into the fitting holes 41 of the valve body 40. An O-ring 17 is attached between the fixed iron core 9 and the front end of the bobbin 5 to provide a sealing function so that the oil inside does not leak to the outside. A through-hole 9b is formed in the axial center of the fixed iron core 9, and one end of the pin 1 is connected to a spool (not shown) of the valve body 40.
2 is inserted, and the cutout surface formed in the pin 12 in the axial direction serves as a passage for the oil flowing from the valve body 40.

The movable core 1 is provided on the rear end face of the fixed core 9.
A rib 9c is formed so as to protrude toward the movable iron core 11 in order to reduce residual magnetism at the time of release of the suction from the core 1.

Then, the tip surface 9d of the fixed iron core 9 and the valve body 4
A wavy washer 35 having the same shape as that of the washer 15 is disposed between the washer 0. The washer 35 presses the stationary core 9 toward the bobbin 5 from the valve body 40 side, thereby eliminating the backlash in the axial direction of the stationary core 9 disposed in the bobbin 5.

The movable core 11 is formed in a round shape so as to be slidably fitted in the bobbin 5 as described above, and the other end of the pin 12 is connected to the front end face, and the movable core 11 slides. At the same time, the spool of the valve body 40 is moved via the pin 12.

Therefore, the bobbin 5 is provided by the washer 15 described above.
Is pressed toward the valve body 40 and the fixed iron core 9 is pressed toward the bobbin 5 by the washer 35, so that the movable iron core 11 is attracted to the fixed iron core 9 or moves back to return to the rear wall 5a of the bobbin 5.
When the movable core 11 is stopped by colliding with the stopper portion 54, the movable core 11 is stably operated by preventing the bobbin 5 from moving up and down with respect to the outer case 3, and furthermore, the stopper of the movable core 11 is Since the impact force on the portion 54 is reduced, damage to the bobbin 5 can be extremely reduced.

The electromagnet 1 constructed as described above constitutes a hydraulic solenoid valve by attaching the flange portion 3a of the outer case 3 to, for example, a hydraulic valve body 40. in this case,
A pin 12 for moving a spool of the valve element 40 is provided between the movable iron core 9 and the valve element 40 through a through hole 9 b of the fixed iron element 9.
It is arranged while being inserted through. Since the pin 12 is round and has cutout surfaces on both sides, oil flows into the electromagnet 1 from between the through hole 9b and the cutout surface of the pin. When the coil 7 is excited, the fixed core 9 and the movable core 11
A magnetic field is generated in the yoke 13 and the outer case 3, and the movable core 1
1 moves in the direction in which it is attracted to the fixed core 9 and
The movable iron core 11 is sucked. At this time, the play due to the tolerance of the fixed iron core 9 is absorbed by the wavy washers 15 and 35 having elasticity, so that the movable iron core 11 can be moved stably.

When the excitation of the coil 7 is released, the magnetic field is demagnetized between the fixed core 9 and the movable core 11, so that the movable core 11 is separated from the fixed core 9 via a pin 12 by a spring (not shown). Will move in that direction. The movable iron core 11 returns and collides with a stopper portion 54 formed on the rear wall 5a of the bobbin 5, and stops. At this time, since the tube body 4 is pressed toward the valve body 40 by the seat plate 15 at the rear end, the vertical play with respect to the outer case 3 is absorbed, and the movement of the tube body 4 by the play is prevented. . Furthermore, the impact force of the washer 15 is reduced by the elastic force.

In the present invention, the washer may be simply arranged between the rear wall 5a of the bobbin 5 and the rear wall 3c of the outer case 3, and the washer between the distal end face 9d of the fixed iron core 9 and the valve body 40 may be provided. It may be arranged only between them, or both may be arranged.

Further, the corrugated washer is not limited to the above-mentioned form, but may be any one which has elasticity and can be easily manufactured by press working. Further, it may be formed in a long shape instead of a round shape.

The tube constituting the tube body is not limited to the bobbin, but may be a non-magnetic pipe which is housed in the bobbin and whose rear end face is closed.

[0026]

According to the present invention, the electromagnet includes an outer case having an open end and a coil housed therein, a movable core disposed in the outer case and slidably disposed therein, and a distal end portion. A tube body in which a fixed core is fixedly disposed, and the fixed core is fitted and held in an object to be mounted, and the movable core is an electromagnet that is attracted to the fixed core by excitation of the coil, Between the rear end of the outer case and the rear end of the tube body, or between the rear end of the outer case and the rear end of the tube body, and the front end face of the fixed iron core and the attached object In order to eliminate the backlash that occurs in the axial direction of the tube body, a member having elasticity is arranged between the two. Therefore, since the backlash in the axial direction of the tube body, which is generated when the electromagnet is attached to the valve body or the like of the object to be mounted, can be absorbed, at the time of the return movement of the movable core, the play of the tube body at the time of the collision of the movable iron core is reduced. The movement can be prevented, and the impact force can be reduced by the elastic force. Further, this configuration can reduce the cost because the number of components is reduced as compared with the conventional configuration.

If the elastic member is a washer formed in a wavy shape, not only a commercially available washer can be used, but also a space corresponding to the thickness of the washer plate is sufficient, so that the electromagnet can be formed compact.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an electromagnet according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a wavy washer in FIG. 1;

FIG. 3 is a sectional view showing a conventional electromagnet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electromagnet 3 ... Outer case 3c ... Rear wall 5 ... Bobbin 7 ... Coil 9 ... Fixed iron core 11 ... Movable iron core 12 ... Pin 13 ... Yoke 15, 35 ... Washer 40 ... Valve body

Claims (3)

[Claims] 1. An outer case having an open end and accommodating a coil, a movable core disposed in the outer case and slidably disposed therein, and a fixed iron core fixedly disposed at a distal end portion. The fixed iron core is inserted and held in an object to be mounted, and the movable iron core is an electromagnet that is attracted to the fixed iron core by excitation of the coil. Between the rear end portion of the tube body, or between the rear end portion of the outer case and the rear end portion of the tube body, and between the front end surface of the fixed core and the attached object, An electromagnet, wherein an elastic member is provided to eliminate backlash generated in the axial direction. 2. The electromagnet according to claim 1, wherein the elastic member is a washer formed in a wave shape. 3. The electromagnet according to claim 1, wherein the tube body includes a bobbin around which the coil is wound and whose rear portion is closed with a rear wall.