JPH10289819A - Electromagnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnet of which cost can be reduced and quality can be improved, by reducing remaining magnetism without using a remaining magnetism spacer. SOLUTION: An electromagnet S1 is provided with a fixed iron core 6 and a movable iron core 7 to be moved in an approaching/separating direction to/from the iron core 6. A recessed part 62 is formed on the movable iron core side end part of the core 6 from its end face 61 to the inside, and the recessed part 62 is formed as two stepped recessed part having an intermediate step face 63 and a bottom 64. On the other hand, a projected part 72 is formed on the fixed iron core side end part of the core 7 from its end face 71 to the inside. When the core 7 is moved so as to be attracted to the core 6, the projected end face 73 of the core 7 is abutted on the intermediate step face 63 of the core 6. Since the core 6 is formed so that the side thickness of the intermediate step face 63 is about 1 to 3 mm and length between the face 63 and the bottom 64 is about 0.2 to 0.5 mm, an abutting area between both the cores 7, 6 is small and its gap is extremely slight. As a result, remaining magnetism can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electromagnet,
More specifically, the present invention relates to preventing residual magnetism generated when a movable core is released from being attracted to a fixed core.

[0002]

2. Description of the Related Art Generally, when an electromagnet is energized by a coil, a magnetic flux is generated between a yoke, a movable iron core and a fixed iron core, and the movable iron core is moved toward the fixed iron core by its magnetic force. When the energization of the coil is stopped, the magnetic flux disappears, and the movable iron core is returned to the original position by a spring or the like. When the coil is de-energized and the movable core returns to its original position, if there is residual magnetism between the movable core and the fixed core, the movable core is attracted to the fixed core due to a slight magnetic force and the return is delayed. For example, it affects the performance of the valve. Therefore, in the electromagnet, usually, a spacer for preventing residual magnetism of a non-magnetic material is fixed to the movable iron core between the movable iron core and the fixed iron core.

Conventional spacers for preventing residual magnetism are disposed on a movable core in various states as shown in FIGS.

[0004] In the electromagnet S3 of FIG.
Inside, a bobbin 23 around which the coil 22 is wound is disposed,
The fixed iron core 25 is provided so as to be fixed to one of the bobbins 23. A movable iron core 27 is provided on the other
However, the pin 28 formed in a two-stage diameter has a small diameter portion 28a.
Is disposed so as to be press-fitted, and the large-diameter portion 28b of the pin 28 is
Are slidably fitted in the shaft hole 25a of the fixed iron core 25. Further, on the side of the movable iron core 27 facing the fixed iron core 25, a valve connecting pin 29 is fixed along the axis so as to be connected to a valve (not shown). And
The spacer 26 for preventing residual magnetism is pinched between the end face of the movable iron core 27 and the large diameter portion 28a of the pin 28.
8 is supported and arranged on the outer periphery of the small diameter portion 28a.

When the coil 22 is energized, the movable iron core 27 is attracted to the fixed iron core 25 until the end surface of the movable iron core 27 contacts the spacer 26 for preventing residual magnetism, and a valve (not shown) is operated. When the energization of the coil 22 is stopped, the movable iron core 27 is returned to the original position by a spring (not shown), and at the same time, the valve is returned.

The electromagnet S4 shown in FIG. 5 differs from the electromagnet S3 shown in FIG. 3 in that a spacer 36 for preventing residual magnetism is supported by a large-diameter portion 38b of a pin 38 pressed into a movable iron core 37. However, the large diameter portion 38b of the pin 38 slides in the shaft hole 35a of the fixed iron core 35, and other configurations are the same as those of the electromagnet S3 of FIG.

In the electromagnet S5 shown in FIG. 6, a spacer 46 for preventing residual magnetism is fixed to a movable iron core 47 by bolts 48 toward a fixed iron core 45 side. A hole 45a into which the head of the bolt 48 is loosely fitted is formed in the fixed iron core 45.

In the electromagnet S6 shown in FIG. 7, the spacer 56 for preventing residual magnetism is attached to the movable core 5 by an adhesive.
7 is fixed to the fixed iron core 55 side.

The movable core 3 of the electromagnet shown in FIGS.
On the side of the fixed iron cores 7, 47, 57 opposite to the fixed iron core 35, 45, 55 side, valve connecting pins 39, 49, 59 connected to valves (not shown) are provided with movable iron cores 37, 47,
57.

Further, in the electromagnet S7 shown in FIG. 8, a spacer 86 for preventing residual magnetism is provided on the outer peripheral edge of the fixed iron core 85 at the end face of the fixed iron core 85 disposed in the pipe 83 on the movable iron core 87 side. Are arranged along. The remnant magnetism preventing spacer 86 is formed in a ring shape so that a part thereof is missing from the entire circumference, and is formed in a spring shape so as to urge outward. And if it is arrange | positioned in the outer peripheral edge part outside the recessed part of the fixed iron core 85 which has a recessed part at an end,
It is attached so as to press the inner peripheral surface of the pipe 83.
When the movable core 87 is attracted to the fixed core 85, the outer peripheral edge of the movable core 87 having a convex portion at the end thereof comes into contact with the residual magnetism preventing spacer 86.
7 is released, no residual magnetism remains, and the movable core 87
Can return immediately.

[0011]

However, the fixing of the spacer for preventing residual magnetism to the movable iron core in the conventional electromagnet has the following problems.

In the electromagnets S3 and S4 shown in FIGS. 4 and 5, the pins 28 and 38 must be newly manufactured, which not only increases the number of parts but also guides the pins 28 and 38 to the fixed iron cores 25 and 35. Since the holes 25a and 35a are formed, the processing cost is increased. In the electromagnet shown in FIG. 5, when the pin 38 comes out of the hole 35a of the fixed iron core 35, the spacer 36 for preventing residual magnetism easily falls.

In the electromagnet S5 shown in FIG. 6, since the bolt 48 is stopped, if the screw of the bolt 48 is loosened, the head of the bolt 48 interferes with other parts or the bolt 48 comes off and the spacer for preventing residual magnetism is removed. 46 easily falls. Also,
In the electromagnet S6 in FIG. 7, since the spacer 56 for preventing residual magnetism is fixed with an adhesive, the adhesive is easily peeled off.

Further, in the electromagnet S7 shown in FIG. 8, the spacer 86 for preventing residual magnetism may cause a problem of deformation or breakage, and the cost is increased due to an increase in the number of parts.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and reduces the cost by eliminating the conventional remanent magnetic spacer. It is an object of the present invention to provide an electromagnet capable of reducing the electric current.

[0016]

An electromagnet according to the present invention has the following configuration to solve the above-mentioned problems. That is, a bobbin formed in a hollow shape and around which a coil is wound, a fixed core disposed on an inner peripheral surface of the bobbin, and a movable core movably disposed with respect to the fixed core. An electromagnet provided with a recess formed inward from an end face at the movable core side end of the fixed core, and an outwardly directed end face at the fixed core side end of the movable core. A convex portion facing the concave portion is formed, and when the movable core is attracted to the fixed core, an end of the fixed core and an end of the movable core are formed so as to partially contact each other. It is characterized by that.

Preferably, the concave portion of the fixed core is formed as a two-step concave portion having a middle surface and a bottom surface, and the end face of the convex portion of the movable iron core can contact the middle surface of the concave portion of the fixed core. What is necessary is just to be the thing characterized by being formed in.

Further, the recess of the fixed core is formed as a two-step recess having a middle surface and a bottom surface, and the end face of the movable core can be brought into contact with the end face of the recess of the fixed core. It may be characterized by being formed.

Furthermore, the convex portion of the movable iron core is formed as a two-step convex portion having a front end surface and a middle step surface, and is formed so as to be able to contact the bottom surface of the concave portion of the fixed iron core. May be used.

[0020]

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

FIG. 1 shows an electromagnet S1 according to a first embodiment of the present invention. Coil 2 in case 1
Is wound, and a yoke 4 is arranged adjacent to the side of the bobbin 3. The bobbin 3 and the yoke 4 are formed in a hollow shape, and a fixed iron core 6 is fitted and fixed to the inner peripheral surface of the bobbin 3.

The movable core 7 is movably fitted to the bobbin 3 so as to approach and separate from the fixed core 6. A pin 9 is disposed on a side of the movable core 7 opposite to the fixed core 6 side, and a tip end of the pin 9 is connected to a spool S movably disposed on the valve body B. It is configured so that the road entrance can be opened and closed. A coil spring 10 is provided around the pin 9. The electromagnet S1 is disposed on both sides of the valve body B (so-called double solenoid), and the coil spring 1
0 urges the movable iron core disposed on the opposite side of the valve body B in a direction away from the fixed iron core.
The movable iron core 7 is separated from the fixed iron core 6 by a coil spring arranged on one of the electromagnets.

An end face 6 is provided at the end of the fixed iron core 6 on the movable iron core side.
1 and inwardly, a recess 62 is formed.
Are formed in a two-step recess having a middle surface 63 and a bottom surface 64. Also, at the fixed core side end of the movable core 7,
A protrusion 72 is formed outward from the end face 71 so as to face the recess 62 of the fixed iron core 6. Then, the convex end face 73 of the movable iron core 7 is formed so as to be able to contact the middle step surface 63 of the fixed iron core 6.

The contact width between the convex end face 73 of the movable core 7 and the middle step 63 of the fixed core 6 is about 1 to 3 mm in one thickness L, and the length of the middle step 63 and the bottom face 64 of the fixed core 6 H is formed at about 0.2 to 0.5 mm. Therefore, in a state where the movable core 7 is attracted to the fixed core 6 and the convex end face 73 of the movable core 7 is in contact with the middle surface 64 of the fixed core 6,
The contact width is small, and the gap between the movable core 7 and the fixed core 6 is small. As a result, the movable core 7 is
In this state, even if the residual magnetism remains, its magnetic force is small, and the influence of the residual magnetism is small.

When the coil 2 of the electromagnet S1 constructed as described above is energized, a magnetic flux is generated in the yoke 2, the fixed core 6, and the movable core 7, and the movable core 7 moves toward the fixed core 6 in the figure. , Move left. The spool is moved to the left along with the movement of the movable iron core 7, and the operation is performed so that hydraulic pressure flows.

When the energization of the coil 2 is stopped, the magnetic flux disappears, and the movable iron core 7 moves rightward in FIG. At this time, a small amount of residual magnetism remains between the movable core 7 and the fixed core 6, but since the contact surface between the movable core 7 and the fixed core is small, the movable core 7 is smoothly moved, and the response delay of the spool is delayed. Does not occur.

FIGS. 2 and 3 show another form of the ends of the movable core 7 and the fixed core 6. In FIG. 2, the movable core side end of the fixed core 11 extends inward from the end face 11 a. The concave portion 12 is formed toward the intermediate surface 12.
a, and a two-step recess having a bottom surface 12b. In addition, the end face 1 is provided at the fixed core side end of the movable core 13.
A projection 14 is formed outward from 3a so as to face the recess 12 of the fixed iron core 11. Then, the end face 13 a of the movable iron core 13 is formed so as to be in contact with the end face 11 a of the fixed iron core 11. The contact width between the end face 13a of the movable core 13 and the end face 11a of the fixed core 11 is, as described above, the _one-side thickness L1 is about ₁ to 3 mm.
1a and length H ₁ of the middle surface 12a is about 0.2~0.5mm
It is formed in the place. Therefore, in a state where the movable core 13 is attracted to the fixed core 11 and the end face 13 a of the movable core 13 is in contact with the end face 11 a of the fixed core 11, the contact width is small, and the movable core 13 and the fixed core 11 The gap is small. Thus, when the movable core 13 is released from the fixed core 11, the magnetic force is small even if the residual magnetism remains, and the influence of the residual magnetism is small.

In FIG. 3, a concave portion 1 is provided at the end of the fixed core 16 on the movable core side inwardly from the end face 16a.
7 are formed, and the concave portion 17 has a bottom surface 17a.
An end face 18a is provided at the end of the movable core 18 on the fixed core side.
The convex portion 19 is formed so as to face outward from the concave portion 17 of the fixed iron core 16. The convex portion 19 is formed as a two-stage step-shaped convex portion having a convex end face 19a and a middle step surface 19b. Then, the convex end face 19a of the movable iron core 18
Are formed so as to be able to contact the bottom surface 17 a of the fixed iron core 16.
End surface 18a of convex portion of movable core 18 and bottom surface 1 of fixed core 16
Contact width between 7a is similar to the above, KatanikuAtsu L ₂ is 1~3m
m is around, the length H ₂ of protrusion end face 19a and the middle surface 19b of the movable core 18 is formed in approximately 0.2~0.5mm position. Therefore, in a state where the movable core 18 is attracted to the fixed core 16 and the convex end face 19a of the movable core 18 is in contact with the bottom surface 17a of the fixed core 16, the contact width is small,
The gap between the movable core 18 and the fixed core 16 is small. Thus, in a state where the movable core 18 is released from the fixed core 16, even if the residual magnetism remains, the magnetic force is small and the influence of the residual magnetism is small.

As described above, when the movable core and the fixed core are attracted to each other, the contact surface thereof is reduced, so that when the suction is released, the residual magnetism preventing spacer is not used and the residual magnetism is prevented. The effect can be reduced.

In the present embodiment, the movable core has been described as being of a type disposed at a position opposite to the valve side with respect to the fixed core, but the electromagnet of the present invention is not limited to this. The movable core may be of a type used between the fixed core and the valve.

[0031]

As described above, according to the electromagnet of the present invention, the electromagnet includes a bobbin formed in a hollow shape and around which a coil is wound, and a fixed iron core disposed on the inner peripheral surface of the bobbin.
A movable core movably disposed with respect to the fixed core. A concave portion is formed inward from the end face at the movable core side end of the fixed core,
A convex portion facing the concave portion is formed outward from an end face at an end of the movable core on the fixed core side. When the movable core is attracted to the fixed core, the end of the fixed core and the end of the movable core are formed so as to partially contact each other. It is small and can reduce remanence. Therefore,
The effect of residual magnetism can be reduced without using a spacer for preventing residual magnetism.Therefore, the risk of falling when using the spacer and the number of parts due to eliminating the spacer are reduced. Reduction (cost reduction) can be achieved.

[Brief description of the drawings]

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

FIG. 2 is a partial cross-sectional view showing another embodiment of a movable core and a fixed core.

FIG. 3 is a partial cross-sectional view showing still another embodiment of a movable core and a fixed core.

FIG. 4 is a diagram showing a state in which a spacer for preventing residual magnetism is mounted in a conventional electromagnet.

FIG. 5 is a diagram showing a state in which a spacer for preventing residual magnetism is mounted in a conventional electromagnet.

FIG. 6 is a diagram showing a state in which a spacer for preventing residual magnetism is mounted in a conventional electromagnet.

FIG. 7 is a diagram showing a state in which a spacer for preventing residual magnetism is mounted in a conventional electromagnet.

FIG. 8 is a diagram showing a state in which a spacer for preventing residual magnetism is mounted in a conventional electromagnet.

[Explanation of symbols]

 S1 ... electromagnet 2 ... coil 3 ... bobbin 6, 11, 16 ... fixed iron core 7, 13, 18 ... movable iron core 11a, 16a, 61 ... end face of fixed iron core 12, 17, 62 ... concave part 12a, 63 ... middle cross section 12b, 17a, 64: Bottom surface 13a, 18a, 71: End surface of movable core 14, 19, 72: Convex portion 19a, 19a, 73: Convex end surface 19b: Medium cross section

Claims (4)

[Claims] 1. A bobbin formed in a hollow shape and around which a coil is wound, and a fixed iron core disposed on an inner peripheral surface of the bobbin;
A movable core movably disposed with respect to the fixed core, wherein a concave portion is formed inward from an end face at an end of the fixed core on the movable core side; A convex portion facing the concave portion is formed outward from an end face at the fixed core side end portion of the movable core, and when the movable core is attracted to the fixed core, the end portion of the fixed core and the An electromagnet, wherein an end of a movable iron core is formed so as to partially contact each other. 2. The recess of the fixed core is formed in a two-step recess having a middle surface and a bottom surface, and the end face of the convex portion of the movable core is formed so as to be able to contact the middle surface of the recess of the fixed core. The electromagnet according to claim 1, wherein the electromagnet is used. 3. The recess of the fixed core is formed as a two-step recess having a middle surface and a bottom surface, and the end face of the movable core can contact the end face of the recess of the fixed core. The electromagnet according to claim 1, wherein the electromagnet is formed. 4. The movable core according to claim 1, wherein the convex portion of the movable core is formed as a two-step-shaped convex portion having a front end surface and a middle surface, and is formed so as to be able to contact the bottom surface of the concave portion of the fixed core. The electromagnet according to claim 1, wherein