JP3536307B2 - Electromagnetic coil - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic coil mainly used for an electromagnetic relay, and more particularly, to a method for stably holding a coil bobbin with a jig and for holding the coil bobbin. The present invention relates to a technique for effectively utilizing the configuration to increase the coating strength by insert molding. 2. Description of the Related Art Conventionally, in manufacturing an electromagnetic coil used for an electromagnetic relay, a coil bobbin having an iron core inserted therein is held by a claw of a jig, and the coil is wound around the coil bobbin. And insert-molded into the resin body. [0003] However, in such a configuration, the coil bobbin is held by the claw of the jig and the coil is wound around the coil bobbin. The coil bobbin is easily detached from the jig,
In addition, when the coil including the coil bobbin is molded into the resin body by the insert molding, there is a problem that it is difficult to increase the connection strength between the molded layers that are formed into two layers. [0004] The present invention has been made in view of such a problem, and an object thereof is to stably hold a coil bobbin with a jig by a simple improvement, and to effectively use a configuration for holding the coil bobbin. An object of the present invention is to provide an electromagnetic coil capable of increasing the coating strength by insert molding by utilizing the method. According to the present invention, a coil bobbin 2 in which an iron core 1 is inserted is held by a rotating jig 19, and a coil 3 is wound around the coil bobbin 2.
An electromagnetic coil which also has the resin body 14 secondary insert molding is performed the coil 3, including both of the coil bobbin 2
A concave groove 18 is formed on the upper and lower surfaces of the end holding portion 2a in the horizontal direction in which the resin layer enters and is held by the jig 19 rotating on the coil bobbin 2 and the secondary insert molding is performed.
Is formed is characterized in Rukoto. The two-way concave groove 18 of the coil bobbin 2 is securely held by a jig, and the coil bobbin 2 is swung by centrifugal force due to the rotation of the jig, so that the claws of the jig slip and the coil bobbin 2 Is prevented from coming off the jig. Moreover, the resin layer enters into the two-way concave groove 18 by secondary insert molding,
This increases the coating strength of the secondary insert layer. An embodiment of the present invention will be described below in detail with reference to the drawings. In the electromagnetic relay of the present embodiment, as shown in FIG. 1, an iron core 1 is formed in a substantially U-shape, and the iron core 1 is arranged with both side pieces facing upward. A coil bobbin 2 made of synthetic resin is integrally formed with the iron core 1. That is, the iron core 1 is insert-molded on the coil bobbin 2. Here, the tip portions of both side pieces that become the magnetic poles of the iron core 1 are exposed from the coil bobbin 2. A coil 3 is wound around an iron core 1 between the coil bobbins 2. A rectangular parallelepiped permanent magnet 4 is attached between both side pieces of the iron core 1 exposed from the coil bobbin 2. The permanent magnet 4 is magnetized in different polarities at the center and both ends. The manufacturing process of each of the above members will be described. First, a coil bobbin 2 is manufactured by inserting an iron core 1 therein.
The coil 3 is wound around the iron core 1 between the coil bobbins 2, and then the permanent magnet 4 is attached. In the following description, a member including the iron core 1, the coil bobbin 2, the coil 3, and the permanent magnet 4 is referred to as an electromagnet block. The electromagnet block is molded integrally with the terminal 7 with a synthetic resin to form a body block 16 shown in FIG. Terminal 7 above
Are a fixed terminal 13 having a fixed contact 9 formed at a base end, a common terminal 12 having a fixed piece 7a formed at a base end with a hinge spring piece 6a of a contact spring 6 to be described later, The two fixed terminals 13, one common terminal 12, and two coil terminals 11 are respectively implanted on both sides of the electromagnet block. The upper surface of the base of the common terminal 12 is molded so as to be exposed from the upper surface of the body block 16. Then, after the formation, the portions exposed from the molded portions of the respective terminals 7 are bent downward. The armature 5 is disposed on the permanent magnet 4 of the body block 16. The armature 5 is formed in the shape of a flat plate, forms a ridge (not shown) serving as a swing fulcrum at the center of the lower surface, and is swingably mounted on the permanent magnet 4. A contact spring 6 is integrally attached to the armature 5. In the case of the present embodiment, since it is a two-circuit type polarized relay, two contact springs 6 are provided on both sides of the armature 5. A movable contact 8 is fixed to each end of the contact spring 6, and a hinge spring piece 6a is protruded from one side of a central portion. The hinge spring piece 6a is fixed to the fixing piece 7a of the common terminal 12, whereby the contact spring 6 is electrically connected to the common terminal 12. The hinge spring piece 6a also has a function of applying a restoring force to the armature 5 due to the twist generated when the armature 5 is attracted to one of the side pieces of the iron core 1. Also,
In this embodiment, the armature 5 and the contact spring 6 are molded with a synthetic resin to be integrally formed as an armature block 12. The following steps are taken in assembling the permanent magnet 4. That is, the permanent magnet 4 is positioned and fixed between the pole pieces of the iron core 1 to form the block body 15, and thereafter, the coil terminal 11, the common terminal 12, and the fixed contact 9 are provided on the periphery of the block body 15 as described above. The fixed terminal 13 is provided, and the secondary insert molding of the resin body 14 is performed to manufacture the body block 16. As shown in FIG. 1, concave grooves 18 are formed in the upper and lower surfaces of the holding portion 2a formed by resin molding at both ends of the coil bobbin 2 in a horizontal direction. A groove 18 is formed in the direction. As described above, since the concave grooves 18 are formed in the horizontal direction on the upper and lower surfaces of the holding portion 2 a formed by the resin mold at both ends of the coil bobbin 2, the bidirectional concave grooves 18 of the coil bobbin 2 are fixed to the jigs 19. And the coil bobbin 2 is shaken by the centrifugal force due to the rotation of the jig 19, and the claw 20 of the jig 19 is prevented from slipping and the coil bobbin 2 coming off the jig 19. is there. Then, the resin layer of the resin body 14 subjected to the secondary insert molding enters the two-way concave groove 18 to increase the coating strength of the secondary insert layer. With the armature 5 placed and mounted on the permanent magnet 4 of the body block 16 as described above, the cover 17 shown in FIG. 2 is fitted. The cover 17 has a box shape with an open lower surface, and a sealing portion 17a for sealing the inside is formed at one corner of the upper surface. By the way, the resin body 14 to be subjected to the secondary insert molding uses a liquid crystal resin having a small degree of polymerization, so that the flow viscosity of the resin in the secondary molding is reduced, and the disconnection of the coil 3 is caused by the flow pressure of the resin in the secondary molding. The thickness of the resin around the coil 3 in the resin body 14 can be reduced.
In this case, the degree of polymerization uses a liquid crystal resin having a value of μ = 1000 poise at 300 ° C. or 100 = poise at 340 ° C. Such data is readily apparent from FIGS. In this way, by lowering the degree of polymerization, the injection pressure in the secondary molding can be reduced, disconnection due to resin flow in the coil 3 is suppressed, and furthermore, thin-wall molding becomes possible, and miniaturization of the electromagnetic relay becomes possible. It becomes. FIG. 6 shows another embodiment, in which a resin body 14a as shown in FIG. 6 is insert-molded around a block 15 as shown in FIG. As described above, the present invention relates to a coil bobbin.
Whether grooves are formed on the upper and lower surfaces of both ends in the horizontal direction in which the resin layer enters and is held by the jig rotating on the coil bobbin and the secondary insert molding is performed. Thus, the concave grooves on the upper and lower surfaces of both ends of the coil bobbin can be securely held by the jig, the coil bobbin is shaken by centrifugal force due to the rotation of the jig, the claws of the jig slide, and the coil bobbin is There is an advantage that it is possible to prevent the resin layer from falling out of the groove and to insert the resin layer into the concave groove by secondary insert molding, thereby increasing the coating strength of the secondary insert layer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a coil bobbin according to an embodiment of the present invention;
(A) is a plan view, (b) is a cross-sectional view taken along a line AB in (a),
(C) is a sectional view taken along line CD in (a). FIG. 2 is a perspective view showing an assembling procedure of the same. FIG. 3 is an exploded perspective view of the same. FIG. 4 is a graph showing the results of a flow test with the molding thickness on the horizontal axis and the flow length on the vertical axis. FIG. 5 is a graph showing the results of measurement of fluidized clay with temperature on the horizontal axis and poise on the vertical axis. FIG. 6 shows another embodiment of the above, wherein (a) is a plan view,
(B) is a sectional view taken along line EFGH of (a).
(C) is a half sectional view. [Description of Signs] 1 Iron core 2 Coil bobbin 3 Coil 14 Resin body 18 Concave groove

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-192236 (JP, A) JP-A-3-77408 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 49/00 H01F 5/02

Claims (1)

(57) [Claims] [Claim 1] A coil bobbin in which an iron core is inserted is held by a rotating jig, and a coil is wound around the coil bobbin.
An electromagnetic coil in which a coil including a coil bobbin is subjected to secondary insert molding in a resin body, wherein the coil bobbin
The upper and lower surfaces of both ends are held by the jig rotating on the coil bobbin, and are formed with horizontal grooves into which the resin layer enters when secondary insert molding is performed . <Br / > An electromagnetic coil characterized by: