JPS61276204A - Sheet type permanent magnet - Google Patents

Abstract

PURPOSE:To make thinner the thickness of a sheet type permanent magnet, and at the same time, to give a mechanical strength, a toughness and a flexibility to the permanent magnet by a method wherein the synthetic resin molding materials containing rigid magnetic powders are reinforced with fibers or textile fibers. CONSTITUTION:Rigid magnetic powders 1 are made of the fine powders of a rigid magnetic material, such as ferrite, rare earth elements or Alnico, and synthetic resin materials 2 are made of a thermoplastic resin material, such as a polyethylene resin and a vinyl chlorine resin, or a thermosetting resin material, such as a phenol resin, a urea resin and an epoxy resin. Moreover, as fibers (staple fibers) 3 or such compositional fibers as the textile fibers, which are used as the reinforcing materials for the synthetic resin molding materials, are used various vegetable fibers, synthetic fibers having a melting point higher than the molding temperature of a sheet type permanent magnet 4, such as nylons 66, or inorganic fibers, such as glass fibers, Kevlar fibers and carbon fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to the production of sheet-like permanent magnets used, for example, in arm bands and shoe insoles for medical and health purposes, or in suction devices such as hangers. More specifically, the present invention relates to a sheet-like permanent magnet that can prevent cracking or chipping even when bent or stretched.

(Prior Art) Conventionally, this type of sheet-like permanent magnet has been formed by mixing hard magnetic powder with a synthetic resin material and molding the mixture. By molding using a molding material in this way, the magnetic strength can be set to a desired value by adjusting the amount of magnetic material added, and the shape can be formed arbitrarily.

(Problems to be solved by the invention) However, such conventional sheet-shaped permanent magnets
Since the magnetic powder is a hard particle and the mixing ratio thereof is generally high, for example reaching about 90% by weight, it has a wood-like problem of weak mechanical strength. -For this reason, when used for shoe insoles, for example, the sheet needs to be fairly thick. Moreover, even with such a large thickness, if the surface is made uneven to improve the magnetic effect, cracks will inevitably occur due to local stress acting on the sheet. In addition, when used as an arm band, for example, there is no problem during normal use, but due to the bending stress that is applied when bending and stretching the arm, cracks may occur in the same way, and in severe cases, cracks may occur. It's something you end up doing.

In this way, conventional sheet-shaped permanent magnets have weak mechanical strength, so the wall thickness cannot be made thinner, and even when the wall thickness is increased to a certain extent, cracks and chips often occur. There was a drawback to doing so. Furthermore, as described above, since the strength is weak, the workability of the magnet sheet is poor, and not only shape processing such as embossing, but also mechanical processing such as press punching is generally impossible.

(Means for Solving the Problems) Therefore, an object of the present invention is to provide a sheet-like permanent magnet that can have a sufficiently thin wall thickness, and that also has excellent workability without cracking or chipping. In order to achieve this objective, the permanent magnet of the present invention is a thin-walled permanent magnet made of hard magnetic powder and a synthetic resin material, and the permanent magnet is reinforced with fiber or woven fabric. This makes it possible to improve mechanical strength and achieve the necessary toughness and flexibility.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1, 2, and 3, a thin sheet-like permanent magnet 4 made of hard magnetic powder 1 and synthetic resin material 2 is reinforced with short fibers 31, long fibers 32, and woven or knitted fabric 33, respectively. ing. In addition, FIG. 3 shows a case where the fabric is reinforced with short fibers 31 in addition to the woven or knitted fabric 33.

Here, the hard magnetic powder 1 is made of fine powder such as ferrite, rare earth, or alnico, and the synthetic resin material 2 is made of a thermoplastic resin material such as polyethylene resin or vinyl chloride resin, or 1 is made of a thermoplastic resin material such as phenol resin or Uniar resin. , made of thermosetting resin material such as Epoquine resin. In addition, long and short fibers 32.3 forming the reinforcing material 3
1 and the composition fibers of the woven and knitted fabrics include various vegetable fibers, synthetic fibers such as nylon 66 having a melting point higher than the forming temperature of the magnet 4, glass fibers, Kepler fibers, Inorganic fibers such as carbon fiber are used.

Next, a method for molding the sheet-like magnet 4 will be explained.0 When the synthetic resin material 2, that is, the molding material is a thermoplastic resin, and the reinforcing material 3 is a fiber, especially a short edge M3+, 1. Usually, the synthetic resin material 2 is a thermoplastic resin. Material 2, short edge! 131 and magnetic powder 1,
In the case of rubber-based resins in which this mixture is compressed, injected, or extruded, a method is used in which a material mixed with fibers is compressed and heated in a mold to perform yli attachment and vulcanization. ), the sheet-like magnet 4 is formed. On the other hand, the synthetic resin material 2 is a thermoplastic or thermosetting resin.

When the reinforcing material 3 is a woven or knitted fabric 33 or a long fiber 32, the magnetic powder 1 and the synthetic resin material 2 are usually mixed or kneaded on the plate 5, as shown in FIG. Place the molded material 5 that has been prepared, place the reinforcing material 3 on the molded material 5, further place the molded material 5 on the reinforcing material 3,
Thereafter, the sheet-like magnet 4 is formed by heating and pressurizing the upper and lower molds 9.8 through the plate 6.7. In this case, the molding material 5 and the reinforcing material 3 can be laminated in double or triple layers, and short fibers 31 can also be mixed into the molding material 5 as shown in FIG.

By reinforcing the sheet magnet 4 with the reinforcing material 3 in this way, the thickness of the magnet 4 can be made extremely thin, for example, about 1 m thick, and at the same time, its mechanical strength can be greatly improved. can do. Moreover,? The hardness of the magnet can be arbitrarily set by appropriately selecting the synthetic resin material 2. For example, when attached to fabric or used as an arm band, a soft synthetic resin material, particularly preferably NBR rubber, is used. If the magnet 4 is molded using resin or the like, it is possible to completely prevent the magnet 4 from cracking or missing due to bending or bending. On the other hand, if it is molded using a hard resin material, it can be used in place of a hard magnet such as a ferrite magnet without any problem. Also, furthermore,
Fj1 stone 4 has high mechanical strength as mentioned above, and at the same time can easily impart the necessary toughness and flexibility, so it has extremely good mechanical workability, and therefore,
Not only can cutting holes be processed, but mold material processing such as pressing or embossing can also be easily performed. That is, 1, for example, as shown in FIG. 5, a sheet-like magnet 4 made of a soft resin material is molded using a hot press 10 to form a magnet sheet 4' with an uneven surface, which is used, for example, in the insole of shoes. can be obtained easily. In this case, it goes without saying that the magnet 4 itself can be directly formed into the shape of the magnet sheet 4 when the magnet 4 is molded.

In this way, according to the present invention, by reinforcing an appropriately selected synthetic resin molded material with an appropriately selected fiber or woven or knitted fabric, the wall thickness can be made extremely thin, and at the same time mechanical strength and mechanical strength can be improved. Workability can be greatly improved. Therefore, it is possible to easily and inexpensively manufacture various thin-walled, lightweight magnet products that do not suffer from cracks or chips unlike conventional sheet-like permanent magnets.

(Effects of the Invention) As explained above, in the sheet-like permanent magnet of the present invention, an appropriately selected synthetic resin molded material containing hard magnetic powder is reinforced with an appropriately selected fiber or woven or knitted fabric. By doing so, the wall thickness can be made extremely thin, while at the same time imparting mechanical strength, necessary toughness and flexibility, and greatly improving mechanical workability. However, by using such sheet-like permanent magnets, it is possible to completely prevent the occurrence of cracks and chips that could not be avoided in the past. Easily produce various thin-walled, lightweight sheet-shaped magnet products that are freely processed.
It has the effect of being able to be manufactured at low cost.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are explanatory diagrams of embodiments of the sheet-like permanent magnet of the present invention, and Figure 4 shows the case where it is reinforced with short fibers, long fibers, and woven or knitted fabrics. FIG. 5 is an explanatory diagram showing one embodiment of the molding method. FIG. 5 is an explanatory diagram showing one embodiment of the processing method. l...Hard magnetic powder, 2...Synthetic resin material, 31...
・Short fiber, 32... Long fiber, 33... Woven knitted fabric, 4.
...Sheet-like permanent magnet.

Claims (1)

[Claims] 1. A thin permanent magnet made of hard magnetic powder and a synthetic resin material, characterized in that the permanent magnet is reinforced with fibers or woven or knitted fabric.