JPH0336713A - Manufacture of magnetic core - Google Patents

Abstract

PURPOSE:To eliminate a process for impregnating or coating a synthetic resin and a process for eliminating burr of a cured resin for improving productivity by storing a magnetic core where a magnetic material is laminated and by performing injection and filling of a molten synthetic resin for impregnating or coating the synthetic resin. CONSTITUTION:A toroidal core-shaped magnetic core 2 is constituted by winding a thin amorphous metal film 1. After performing annealing, the magnetic core 2 is stored inside a first mold, molten resin is injected and filled, a synthetic resin is impregnated or coated between the thin amorphous metal films 1 and fixed, and at the same time the surrounding of the magnetic core 2 is covered. A resin to be used should be selected according to the performance required to a core and especially nylon, polyethylene, polyacetal, and a mixture of a reinforced material such as fiber glass to them are suitable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a magnetic core, and particularly to a method of manufacturing a magnetic core made of a magnetic core made of laminated magnetic materials.

[Conventional technology]

Generally, toroidal cores are manufactured by sintering a ferromagnetic material such as ferrite, but in recent years, a method has been adopted in which a thin ribbon of amorphous metal with excellent magnetic properties is wound in a ring. There is one described in Publication No. 134411/1983.

In this type of toroidal core, a thin film is first wound and then impregnated with a synthetic resin such as epoxy, which is then cured after draining the liquid. In some cases, a slit is made in the toroidal core using a cutting machine and a spacer is inserted into the slit.

Furthermore, magnetic cores constructed by laminating magnetic plates, such as the EI type and CI type, are entirely impregnated with synthetic resin in a similar process.

[Problem to be solved by the invention]

However, the conventional manufacturing method described above has a problem in that it is difficult to automate the manufacturing process.

That is, the process of impregnating the synthetic resin, wiping off liquid bleed from the synthetic resin, and cutting off the edges of the cured synthetic resin all involve manual labor, which significantly reduces production efficiency.

Furthermore, when impregnating synthetic resin, vacuum impregnation is performed to penetrate into the inside of the magnetic core, but transporting the workpieces into and out of the vacuum tank interrupts the continuous process, resulting in a decrease in production efficiency.

The present invention has been made in view of the above-mentioned problems, and a technical object thereof is to provide a method for manufacturing a magnetic core that can significantly improve productivity.

[Means to solve the problem]

In order to solve the above technical problem, the present invention employs the following manufacturing method.

That is, the magnetic core 2 formed by laminating magnetic materials 1 is placed in a mold 35.36.
The magnetic core 2 is impregnated or coated with the synthetic resin by injecting and filling the mold 35, 36 with molten synthetic resin.

The molten synthetic resin to be injected is thermoplastic resin.
Low-density polyethylene, high-density polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene, propylene, ■-butene, 4-methyl-1-pentene, etc. Polyolefins such as random or block copolymers of α-olefins, ethylene, acrylic acid copolymers, ethylene, vinyl acetate copolymers, ethylene, vinyl alcohol copolymers, ethylene, ethylene such as vinyl chloride copolymers, Vinyl compound copolymers, polystyrene, acrylonitrile, styrene copolymers, ABS, methyl methacrylate, styrene copolymers, α-methylstyrene, styrene resins such as styrene copolymers, polyvinyl chloride, polyvinylidene chloride, chloride Vinyl, polyvinyl compounds such as vinylidene chloride copolymer, polymethyl acrylate, polymethyl methacrylate, nylon 6, nylon 6-6, nylon 6-10. Polyamides such as nylon 11 and nylon 12, thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate,
Polyphenylene oxide, others, polyparaxylylene, polymonochloroparaxylylene, polydichloroparaquinrylene, polyurethane, silicone, and thermosetting resins such as phenol, epoxy, polyimide, silicone, and alkyd. system, melamine system,
The resin may be urea-based, unsaturated polyester-based, or a mixture thereof.

In this way, various resins can be used, but it is best to select them depending on the performance required for the core, taking into account dielectric constant, insulation resistance, weather resistance, flame retardance, heat resistance, etc. Suitable materials include nylon, polyethylene, polyacetal, and mixtures thereof with reinforcing materials such as glass fiber.

In addition, screw type, plunger type, etc. can be used as injection molding equipment, and the injection pressure is 1 to 1000 K.
g/cm" is suitable, especially from 50 Kg/as' to 200 Kg/as'
Kg/c- is suitable.

The temperature of the molten synthetic resin is 0°C to +300°C higher than the softening temperature or melting temperature, especially +50 to +100°C.
A high temperature around ℃ is best. Further, the magnetic core can be easily held in the mold by providing a fixed support or a movable support, and if a movable support is used, it may be retractable in accordance with the injection pressure.

Furthermore, the magnetic core may be in any form, such as a toroidal core, an El-type core, or a CI-type core.In addition, in the case of a toroidal core, in preparation for molding, the winding of the metal thin film constituting the magnetic core is started. The end of the winding can be temporarily fixed by adhesive, laser welding, spot welding, or other electric welding.

[Effect]

The magnetic core 2 formed by laminating magnetic materials 1 is housed in a mold 35.36, and the synthetic resin layer 5 is formed on the magnetic core 2 by injecting molten synthetic resin into the mold 35.36. A film is instantly formed on the surface, preventing the metal thin film from peeling off or deteriorating. Therefore, the steps of impregnating or coating with a synthetic resin, wiping off liquid bleed of the synthetic resin, and cutting off the edges of the hardened synthetic resin, which were conventionally necessary, are no longer necessary, and production efficiency is improved.

In particular, since vacuum impregnation or coating steps are no longer necessary, the continuity of the manufacturing process is greatly improved.

〔Example〕

Embodiments of the present invention will be described based on FIGS. 1 to 4.

(Example 1) In this example, an amorphous metal thin film is used as the magnetic material 1, and a toroidal core-shaped magnetic core 2 is constructed by winding the amorphous metal thin film.

First, the amorphous gold FiFJ@l cut to a desired width in step (a) was wound in a ring shape in step (b) to form a donut-shaped magnetic core 2 as shown in FIG.

The beginning and end of the winding were temporarily fixed by spot welding. Next, annealing was performed in step (c) to obtain desired magnetic properties.

Next, in step (d), the annealed magnetic core 2 is placed in a mold for injection molding of molten synthetic resin, and the molten resin is injected and filled into the mold by an injection molding machine, and the amorphous metal thin film 1 is synthesized between the amorphous metal thin films 1. Fix by impregnating or coating with resin. As a result, the magnetic core 2
The surrounding area was also covered with glass fiber filled nylon 66 by injection molding.

The apparatus used for the injection molding is of a screw type, and as shown in FIG.
The screw 31 is rotated by a drive device 32.

A hopper 33 is provided above the cylinder 30, and the hopper 33 stores glass fiber-filled nylon 34, which is a resin raw material, and sequentially supplies it into the cylinder 30. On the other hand, a mold 35 is attached to the tip of the cylinder 30. A movable mold 36 is provided on the molding machine base (not shown) so as to be in close contact with the mold 35, and the movable mold 36 is movable in the direction of arrow F by a mold clamping cylinder 3f. There is. A cavity 38 corresponding to the doughnut-shaped magnetic core 2 is formed in the mold 35 and the mold 36. Note that the magnetic core 2 is supported by a supporter 40 that protrudes from the movable mold 36.

At the time of molding, first, the movable mold 36 is moved back, and the magnetic core 2
is installed in the cavity 38. Then, with both molds in tight contact with each other, molten synthetic resin was injected, and the magnetic core 2 was insert-molded with the synthetic resin.

The injection pressure of the molten synthetic resin was 40 Kg/cI++''.

As a result, the completed toroidal core was coated uniformly over the entire circumference and was sufficiently usable.

(Example 2) As in Example 1, the beginning and end of the winding which were wound in the affirmative (b) were temporarily fixed with Kapton tape. This toroidal core was injection molded in step (d) using glass fiber-filled nylon 66 as the molten synthetic resin. The conditions and machine used were the same as in Example 1. The obtained product had good exterior performance and was durable enough for use.

〔Effect of the invention〕

According to the present invention, a synthetic resin layer is formed by housing a magnetic core made of laminated magnetic materials in a mold and injecting molten synthetic resin into the mold, so that a film is instantly formed on the surface of the magnetic core. It is possible to prevent the formed metal thin film from peeling off or deteriorating in quality. This eliminates the need for the conventional steps of impregnating or coating with synthetic resin, wiping off drips from the synthetic resin, and cutting off the edges of the hardened synthetic resin, improving production efficiency. .

In particular, since vacuum impregnation or coating steps are not required, the continuity of the manufacturing process can be greatly improved.

[Brief explanation of drawings]

Figures 1 to 4 show examples of the present invention, Figure 1 is a diagram of the manufacturing process before and after, Figure 2 is a sectional view of the injection molding machine, Figure 3 is a perspective view of the magnetic core, and Figure 4 is a choke It is a perspective view of a coil.・・Magnetic metal thin film, ・Magnetic core, 3. Winding wire, 4. Choke coil, ・Synthetic resin layer.

Claims (1)

[Claims] (1) A magnetic core characterized in that a magnetic core made of laminated magnetic materials is housed in a mold, and the mold is injected and filled with molten synthetic resin to impregnate or coat the magnetic core with synthetic resin. Manufacturing method.