JPH103842A - Electromagnet for electromagnetic contactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnet, which has high contact reliability of a pole piece and a leg part iron core and of which manhours is reduced, by integrally forming the pole piece and the leg part iron core other with cold forging. SOLUTION: A circular iron bar is inserted into a die, and the force is applied from the longitudinal direction of the iron bar, and a lower part is plastically deformed by the cold forging so as to form a plastic iron core 1. A stage difference 1a at a small height can be provided in a flat surface so as to increase the attracting force of a pole piece part. In this structure of an electromagnetic contactor using this iron bar 1, a reset spring 3 is different from a conventional case, besides the iron bar 1. With this structure, efficiency of a closed magnetic path, which is formed by the iron core 1 and a movable iron core 21 and a bottom plate 25 when the current is flowed to a coil 14 and the movable iron core 21 is attracted, is always maintained constant, and the efficiency is improved more by using the iron core 1 with a stage difference 1a. Since the periphery of the pole piece part is formed into a circular shape, a vacant space is formed in each corner of a spool 13, and two reset springs 3 can be provided in these corner spaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electromagnet for an electromagnetic contactor.

[0002]

2. Description of the Related Art As an electromagnetic contactor using an electromagnet according to the present invention, FIG. 3 shows a configuration example of a bridge-type electromagnetic contactor which has been widely used in the past. The electromagnetic contactor comprises an upper opening / closing contact portion and a lower electromagnet as described below. The pair of fixed contacts 25 is attached to the upper case 32 such that the terminal screw 25b screwed to the other end is exposed from the upper case 23 with the fixed contact 25a at one end inside. The movable contact support 22 is fixed to the movable core 21 accommodated in the upper case 32 and the lower case 31 by a pin (not shown) between the fixed contacts 25 so as to be movable up and down. The movable contact support 22 is provided with a movable contact 23 provided with a movable contact 23a capable of bridging between two fixed contacts 25a via a contact spring 24. An open / close contact portion formed by the fixed contact 25 and the movable contact 23 is covered by an arc extinguishing cover 33.

The electromagnets housed in the lower case 31 and the upper case 32 are a bottom plate 15 made of a ferromagnetic material, a coil 14 wound around a spool 13 and fixed to the bottom plate 15, and a leg fitted into the spool 13. It comprises a fixed iron core composed of a part core 11, a pole piece 12 fixed to the movable iron core 21 side of the leg iron core 11, and a movable iron core 21 supported by a return spring 16. This movable iron core 21 is a pole piece 1
2, the movable contact support 22 is moved up and down. The assembling of the leg iron core 11 and the pole piece 12 is performed by aligning the pole piece 12a with the leg iron core 11a as shown in FIG. 4 and fixing it with screws 12b, or as shown in FIG. And the pole piece 12c are welded together and fixed at the welded portion 99 to be assembled. The space of the electromagnet with respect to this electromagnetic contactor is limited to some extent, and there is no space around the square pole piece 12, and a return spring 16 is arranged between the pole pieces 12.

In this configuration, when the coil 14 is energized, the movable iron core 21 is attracted to the pole piece 12, whereby the movable contact support 22 descends and the movable contact 23a contacts the fixed contact 25a to close the main circuit. To achieve. Further, when the energization of the coil 14 is stopped and the movable iron core 21 is released from the pole piece 12 by the return spring 16, the movable contact support 22 rises and the movable contact 23a separates from the fixed contact 25a to open the main circuit. .

[0005]

In the above example, since the pole piece is fixed to the leg core by screws or welding, the contact reliability between the pole piece and the leg core depends on the looseness of the screw and the crack in the welded portion. It depends on the occurrence, etc., and requires many man-hours for processing and assembling, and requires expensive manufacturing equipment for this processing.

An object of the present invention is to provide an electromagnet having high contact reliability between a pole piece and a leg core and requiring a small number of processing steps.

[0007]

According to a first aspect of the present invention, there is provided a fixed iron core having two ends connected to a pole piece at one end thereof, the other ends of which are connected by a bottom plate. A coil wound around the leg core and a movable core that is coupled to a movable contact support that holds a movable contact that comes into contact with and separates from the fixed contact, and that is attracted by electromagnetic force generated in the pole piece by current flowing through the coil. In the electromagnetic contactor provided with the electromagnet, the pole piece and the leg core are integrally formed by cold forging.

The planar shape of the pole piece portion is such that the outer circumferences of the two pole piece portions on the opposite side and the opposite side are asymmetric with respect to the center line of the leg core, and The outer periphery of the plane is preferably formed in a circular arc or an elliptical arc. It is preferable to form a step for increasing the suction force on the plane of the pole piece.

[0009]

FIG. 2 shows an embodiment of the present invention.
(a) is a perspective view of a material, (b) is a processed state in which an upper mold is omitted, and (c) is a perspective view of a part. Round iron bar 7 of the material shown in (a)
1 is put into the mold 91 of (b), a force is applied from the P direction, and the lower part is plastically deformed by so-called cold forging to form the plastic core 1 of (c). Here, in order to increase the suction force of the pole piece portion, a slightly higher step 1a may be provided on the plane. One end of the pole piece portion of the plastic core 1 is linear in order to prevent magnetic leakage between the two pole piece portions, and the other end is asymmetrically formed into a circular arc or an elliptical arc. In order to increase.

FIGS. 1A and 1B show the configuration of an electromagnetic contactor using the plastic core 1. FIG. 1A is a sectional view of a main part, and FIG. The same parts as those in FIG. 3 are denoted by the same reference numerals and description thereof will be omitted. A component other than the plastic core 1 and different from FIG. 3 is a return spring 3 instead of the return spring 16. With this shape, the efficiency of the closed magnetic path composed of the plastic core 1, the movable core 21, and the bottom plate 15 when the current flows through the coil 14 and the movable core 21 is attracted is always constant. If the plastic core 1 having the step 1a is used, the efficiency is further improved. Since the outer periphery of the pole piece portion is formed in an arc shape, an empty space is formed at a corner of the spool 13, and the two return springs 3 are used instead of the conventional return spring 16 by using the space at the corner. Can be provided.

[0011]

According to the first aspect of the present invention, since the leg core and the pole piece are integrated, the magnetic path is not obstructed by the gap between the leg core and the pole piece as in the prior art. In addition, the integration of the leg core and the pole piece can be performed in a short time with high dimensional accuracy by performing cold forging instead of hot forging, which requires many man-hours and requires cutting and large equipment.

Further, since the pole piece portion of the plastic core is formed asymmetrically, the suction force to the movable core is increased, and the outer peripheral space is used for the return spring. And the size of the electromagnetic contactor can be reduced.
According to the third aspect of the present invention, since the outer periphery of the pole piece is formed in an arc or an elliptical arc, cold forging can be completed in a short time, and the efficiency of the magnetic path can be improved. .

[0013] Further, according to the structure of the fourth aspect, since the pole piece portion has a small step in the plane, the attraction force to the movable iron core can be increased.

[Brief description of the drawings]

FIG. 1 is a structural view of an electromagnetic contactor according to an embodiment of the present invention, wherein (a) is a cross-sectional view of a main part, and (b) is a cross-sectional view taken along arrow Q of (a).

FIG. 2 is a view showing a manufacturing process of a plastic core according to the present invention;
(a) is a perspective view of the material, (b) is a perspective view during cold forging with the upper die omitted, and (c) is a perspective view of the finished product.

FIG. 3 is a sectional view of a main part of a conventional electromagnetic contactor.

FIG. 4 is an assembled perspective view of a leg core and a pole piece of a conventional electromagnetic contactor.

FIG. 5 is another assembled perspective view of the leg core and the pole piece of the conventional electromagnetic contactor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plastic core 3 return spring 11 leg core 12 pole piece 14 coil 15 bottom plate 16 return spring 21 movable core 22 movable contact support 24 contact spring 33 arc extinguishing cover

Claims (4)

[Claims] 1. A fixed core formed by connecting the other ends of two leg cores having one end to which a pole piece is connected with a bottom plate, a coil wound around the leg core, and a movable contact which comes into contact with and separates from a fixed contact. An electromagnetic contactor having an electromagnet comprising a movable core coupled to a movable contact support for holding a contact and attracted by an electromagnetic force generated in the pole piece by an electric current flowing through the coil, wherein the pole piece and the leg core are cooled. An electromagnet for an electromagnetic contactor, which is integrally formed by cold forging. 2. The electromagnet of an electromagnetic contactor according to claim 1, wherein the pole pieces have a planar shape in which the outer circumferences of the two pole pieces opposite to each other and opposite to the center line of the leg core. An electromagnet for an electromagnetic contactor characterized by being asymmetric. 3. The electromagnet for an electromagnetic contactor according to claim 1, wherein the outer periphery of the pole piece portion in a plane is formed in a circular arc or an elliptical arc. 4. An electromagnet for an electromagnetic contactor according to claim 1, wherein a plane of the pole piece portion is formed with a step for increasing attraction force. Electromagnet.