JPH05120973A - Coil sealing body for electromagnetic relay - Google Patents

Abstract

PURPOSE:To avoid weld and crack of a fine part by filling the reinforcing material evenly. CONSTITUTION:Coil terminals 3 are planted in a coil bobbin 2 made of glass fiber, and a coil 4 is wound around of the coil bobbin 2, and an iron core 5 and a yoke 6 are inserted for fixation to form a coil assembly 1 as a first molding. An insulating cover 8, to which the single crystal fiber finer than the glass fiber such as potassium titanate fiber or the like is added as the reinforcing material of the heat reversible resin, is formed in the surroundings of the coil assembly 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil sealing body for an electromagnetic relay, and more particularly to a double molded coil sealing body used for a highly insulating electromagnetic relay.

[0002]

2. Description of the Related Art Conventionally, in this type of electromagnetic relay, its coil sealing body is formed by double molding in order to achieve high insulation.

FIG. 4 is a sectional view of a coil sealing body of an electromagnetic relay showing an example of the conventional art. As shown in FIG. 4, the coil sealing body in the conventional electromagnetic relay is the coil terminal 3
And the coil 4 is wound around the coil bobbin 2, and a coil assembly is formed as a first molded body into which the iron core 5 and the yoke 6 are inserted.
Of the coil 4 and the coil terminal 3 are covered with an insulating cover 8a to form a coil sealing body as a second molded body. Here, the coil bobbin 2 forming the first molded body generally uses a reinforced thermoplastic resin containing glass fiber in order to maintain structural strength. The insulating cover 8a forming the second molded body is also made of the same material as that of the coil bobbin 2 forming the first molded body for the purpose of further reinforcing the structural strength.

[0004]

In the coil sealing body of the conventional electromagnetic relay described above, the structure of the second molded body has become complicated due to the recent pursuit of a lighter, thinner, shorter and smaller electromagnetic relay, and the molded product has a thin wall. It is becoming smaller and narrower. Therefore, when the second molded body is molded, there is a risk of coil breakage, and low speed and low pressure molding are necessary conditions. However, in the conventional glass fiber reinforced plastic molding, when molding is performed under these low speed and low pressure conditions, the normal glass fiber has a length of 100 to 200 μm and a diameter of 10 to 15 μm.
Therefore, it is impossible to uniformly fill the glass fibers.
Therefore, due to poor strengthening of fine parts and occurrence of weld,
There is a defect that cracks are generated during environment resistance tests such as high temperature storage and high temperature and high humidity.

An object of the present invention is to provide a coil sealing body for an electromagnetic relay capable of preventing the strength defect and weld of such a minute portion and avoiding the occurrence of cracks.

[0006]

A coil sealing body for an electromagnetic relay according to the present invention comprises a coil bobbin in which a coil terminal is implanted and which encloses an iron core, and a yoke wound around the coil bobbin and coupled to one end of the iron core. A coil assembly arranged on the lower surface and an insulating cover for covering the coil assembly and for covering the coil terminals are provided, and the insulating cover has a single crystal fiber extremely finer than the coil bobbin added as a reinforcing material for a thermoplastic resin. And then formed.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

1 (a) and 1 (b) are perspective views before and after assembly of a coil sealing body in an electromagnetic relay for explaining an embodiment of the present invention. As shown in FIG. 1A, in this embodiment, a coil bobbin 2 made of glass fiber is prepared as a first molded body in which a coil terminal 3 is implanted and a coil 4 is wound. Next, the iron core 5 is penetrated through the center of the coil bobbin 2, the yoke 6 is connected to one end of the iron core 5, and the yoke 6 is arranged on the lower surface of the coil bobbin 2 to form the coil assembly 1. Next, as shown in FIG. 1B, a coil sealing body 7 is formed by covering the coil assembly 1 with a potassium titanate fiber cover 8 which is an insulating cover as a second molded body by injection molding. .. Here, the coil bobbin 2 as the first molded body contains 10% to 30% of glass fiber,
As a result, polybutylene terephthalate whose mechanical strength is improved is used. Further, the cover 8 as the second molded body uses polybutylene terephthalate in which the complicated and narrow portion is reinforced by containing 3% to 30% of potassium titanate fiber. In such a structure, since the flow at the time of molding is good and the orientation of molecules is small, it is possible to suppress the occurrence of welds and cracks and prevent the appearance failure.

Further, in this embodiment, a cover containing potassium titanate fibers was used as the insulating cover, but other fine single crystal fibers may be used as a reinforcing material for the thermoplastic resin.

FIG. 2 is a sectional view of the coil sealing body in FIG. As shown in FIG. 2, since the potassium titanate fiber cover 8 is used as the insulating cover, the narrow portion is reinforced.

FIG. 3 is a sectional view of a coil sealing body showing another embodiment of the present invention. As shown in FIG. 3, this embodiment shows an insulating cover 8 as a second molded body that covers the iron core 5 and the yoke 6 as well. Since this embodiment is integrated, it is possible to minimize lightness, thinness, shortness and miniaturization to prevent thinning and narrowing of the second molded body, and to uniformly fill the resin in every corner to prevent welds and cracks. Occurrence can be avoided.

[0012]

As described above, in the coil sealing body of the electromagnetic relay of the present invention, the insulating cover as the second molded body that covers the coil bobbin as the first molded body is made of the first molded body. By forming a single crystal fiber, which is much finer than a certain coil bobbin, as a reinforcing material of a thermoplastic resin, there is an effect that welds and cracks generated in a thin portion or a narrow portion can be avoided.

[Brief description of drawings]

FIG. 1 is a perspective view before and after assembly of a coil sealing body in an electromagnetic relay for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the coil sealing body in FIG.

FIG. 3 is a sectional view of a coil sealing body showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a coil sealing body of an electromagnetic relay showing a conventional example.

[Explanation of symbols]

 1 Coil Assembly 2 Coil Bobbin 3 Coil Terminal 4 Coil 5 Iron Core 6 Yoke 7 Coil Sealing Body 8 Potassium Titanate Fiber Cover

Claims (2)

[Claims] 1. A coil assembly in which a coil is wound around a coil bobbin in which a coil terminal is embedded and which contains an iron core, and a yoke which is connected to one end of the iron core is disposed on the lower surface of the coil bobbin, and the coil assembly is covered with the coil assembly. An insulating cover for covering the coil terminals, wherein the insulating cover is formed by adding a single crystal fiber which is extremely finer than that of the coil bobbin as a reinforcing material of a thermoplastic resin. body. 2. A coil sealing body for an electromagnetic relay according to claim 1, wherein potassium titanate fiber is used as the single crystal fiber.