JPS6211208A - Permanent magnet - Google Patents

Abstract

PURPOSE:To obtain a thin type permanent magnet, which has uniformity having high precision and thinness and in which defects and damages are not generated, by slicing a sheet material consisting of a synthetic resin and hard magnetic material powder. CONSTITUTION:A sheet material 4 acquired by mixing a synthetic resin 2 and hard magnetic material powder 3 and extruding and roll-molding them is sliced, thus obtaining a thin type permanent magnet. The sheet material 4 is sliced with the exception of a surface layer 4a forming a skin layer in the sheet material 4, thus equalizing the distribution of magnetic material powder 3, then reducing the dimensional error of thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultra-thin permanent magnet that is most suitable for cases where highly accurate uniformity and thinness are required in terms of thickness and quality.

(Prior art) Thin permanent magnets made of the magnetic material ferrite that are commonly used today are molded by sintering, and thin magnets are compression molded by putting ferrite powder into a mold in an amount that corresponds to the thickness. It is then sintered.

(Problem to be solved by the invention) When sintering, it is difficult to uniformly charge the powder material into the mold, and especially in the case of small magnets, the material input is even more difficult because the space for charging is small. There have been many problems such as non-uniformity and non-uniformity in thickness, the production of defective products, which leads to increased costs, and ultra-thin products that are easily damaged.

(Means for Solving the Problems) In order to solve the above problems, this invention
As shown in the figure, a thin permanent magnet 1 is obtained by slicing a sheet material 4 made of a synthetic resin material 2 and hard magnetic material powder 3.

(Function) The surface layer 4a of the sheet material 4 is a skin layer made of the synthetic resin material 2, and the content of the hard magnetic material powder 3 is small and the residual internal stress is high. By slicing, a desired thickness can be freely obtained, and only a homogeneous and distortion-free portion is formed, and the magnetic material powder 3 is cloudy on the back side. It is a permanent magnet l, and is made of a synthetic resin material 2 with good moldability such as nylon, ferrite, alnico, etc.
A hard magnetic material powder 3 such as cobalt or other rare earths is mixed into a thin sheet, and the magnetic material powder 3 is exposed on the surface.

The permanent magnet 1 is obtained by slicing a sheet material 4 obtained by extruding or roll-forming the mixture of the above-mentioned synthetic resin material 2 and hard magnetic material powder 3.

The surface layer 4a of the sheet material 4 is a skin layer and is a part where the content of the magnetic material powder 3 tends to decrease, and the residual internal stress is high, but since this layer is sliced except for the magnetic material powder 3. The content of will be uniform as specified,
Due to slicing, dimensional errors in thickness are extremely small. Also, magnetization is generally performed after slicing.
On the other hand, there are cases where the magnet is sliced after magnetization.

Figure 3 shows an ultra-thin perforated magnet for clothing fasteners using magnets.
It is made by punching out an extremely thin sheet-like permanent magnet 1 obtained by slicing a sheet material 4, and can satisfy the requirements of uniform thickness and homogeneity.

FIG. 4 shows a display sheet 1'', which is made of a synthetic resin material 2 made of vinyl chloride, etc., and is used in the form of a soft sheet that is removably attached to a board made of an iron plate or the like.

(Effects) Since the permanent magnet according to the present invention has a sliced sheet material made of synthetic resin material and hard magnetic material powder, the hard magnetic material powder is uniformly exposed on the surface and the magnetization effect is good. Therefore, the adsorption force is also very good and even.

In addition, thin magnet molding using synthetic resin mixed with magnetic material powder,
This was not possible because as the amount of magnetic material powder mixed into the synthetic resin material increases, the extrusion resistance increases and extrusion molding becomes difficult, but since the permanent magnet according to the present invention is sliced, it is possible to A uniform desired thickness can be freely obtained, for example, 1.5 to 1.5 mm. hm thickness ±111
It is also possible to have an error within 00IIIIII,
This is suitable when dimensional accuracy is particularly required.

Furthermore, since the hard magnetic material powder is linked to the synthetic resin material, it is strong, and due to the viscoelasticity of the synthetic resin, it will not break or break, and if it is soft, it can be bent.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of a permanent magnet according to the present invention, Fig. 2 is a sectional view of a sheet material before being sliced into thin permanent magnets, and Figs. 3 and 4 are perspective views of other embodiments. It is a diagram. 1... Permanent magnet, 2... Synthetic resin material, 3... Magnetic material powder, 4... Sheet material.

Claims (1)

[Claims] A permanent magnet characterized in that a sheet material made of synthetic resin material and hard magnetic material powder is sliced.