JPS63148406A - Production of permanent magnet type erasion head - Google Patents

Abstract

PURPOSE:To improve the quality of a permanent magnet type erasion head together with reduction of its cost by forming previously a core part of said erasion head where a permanent magnet using a resin magnet is inserted and also forming a recess part to an erasion head lever main body in accordance with the shape of the core part. CONSTITUTION:A core part 10 uses an anisotropic resin magnet as a magnetic material and contains a permanent magnet 9 having its tape rubbing surface 7 formed in the shape, dimensions and surface roughness degree of a finished product and the bottom surface of the surface 7 formed into a protruded part 8 respectively. Then such a part 10 is put with pressure into a recess part of an erasion head lever 12. Thus a permanent magnet type erasion head is obtained. As a result, the part 10 has a monolithic structure of the resin magnet used to a part (a part undergone a magnetizing treatment and needed for the erasion head) of the surface 7 and the resin filled into other parts (the parts requiring nonmagnetic parts) of the surface 7 respectively. In such a way, the after-processes are omitted for improvement of the quality and reduction of the cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a permanent magnet erasing head used primarily for erasing audio tapes.

2. Description of the Related Art In general, methods for erasing magnetic recording media such as magnetic tapes include current erasing methods, methods using permanent magnets, and methods using a combination of these methods. A method of manufacturing a conventional permanent magnet erase head will be described with reference to the accompanying drawings. Figure 4 shows the structure of a permanent magnet erase head, and Figure 5 (al,
(bl indicates the erasure principle.

As shown in Figure 4, the core part 2 processed in a separate process was inserted and glued into the eraser lever body 1 as shown in Figures 6 (a) to (cl). .

The core part 2 is processed through a separate and complicated process as shown in Fig. 6a''-c, and after laminating the permanent magnet 3 and the non-magnetic material 4 in Fig. 6fal, it is processed using a diamond cutter. The core 5 was cut into squares to form a core 5 having the predetermined dimensions as shown in Fig. 6 (C1), and one end was polished into an R shape to form a tape sliding surface as shown in Fig. 6 [C1]. In addition, the tape sliding surface of the permanent magnet part 3 of the core part 2 has an alternating pattern of N-4S → N... in the tape running direction, as shown in Figure 5 (8). However, the magnetic field strength gradually decreases as shown in Figure 5 (gradual decreasing alternating type magnetization is applied, and the data recorded and magnetized on the tape is guided to the point where the magnetic field strength becomes zero). It is based on the principle of erasure.

Problems to be Solved by the Invention However, in the conventional manufacturing method, the permanent magnet material is finished into the core part 2 through a complicated processing process, and then the permanent magnet material is pasted into the recessed part 6 of the Radreba body 1 for erasing by pasting with adhesive. It is necessary to fix the adhesive overflow and pasted core part 2
The specifications were unreasonable and wasteful in terms of cost, including quality assurance of the position and angle of the parts.

SUMMARY OF THE INVENTION The present invention aims to provide a method for manufacturing a permanent magnet erasing head which solves the above-mentioned drawbacks of the prior art and makes it possible to reduce costs and improve quality.

Means for Solving the Problems In order to solve the above problems, the present invention uses an anisotropic resin magnet as the magnetic material of the core part, and the tape sliding surface is adjusted to the shape, size and surface roughness of the final finished product. and a permanent magnet type erasing head is obtained by press-fitting a core portion in which a permanent magnet with a convex bottom surface of the tape sliding surface is insert-molded into a recessed portion of the main body of the erasing lever. It is.

Operation With this method, the core part of the permanent magnet erasing head consists of a part of the tape sliding surface (the part that is magnetized and necessary as an erasing head) made of resin magnets, and the rest of the tape sliding surface (the non-polishing part). Since the parts (requiring magnetic parts) are integrally molded with a resin-filled structure, post-processing is unnecessary, making it possible to improve quality and reduce costs at the same time. The erase head lever main body has a structure in which a recess that matches the shape of the core part is provided, and the core part is press-fitted into the recess to perform assembly, thereby improving assembly dimensional accuracy and efficiency of assembly work. This makes it possible to accommodate various changes in the shape and dimensions of the main body of the erase hend lever, making it possible to improve quality and reduce costs at the same time.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1, 2, and 3. FIG. 1 shows a perspective view of a permanent magnet type erasing head according to the present invention, FIG. 2 shows a core part in which a resin magnet is insert-molded, and FIG. 3 shows a resin magnet used in the core part. A permanent magnet 9 is prepared by processing the tape sliding surface 7 into an R shape and having a convex portion 8 on the lower outer periphery. This permanent magnet 9 is made of magnetic powder polyamide with a weight ratio of 87 to 91% made of strontium ferrite magnet for the purpose of reducing manufacturing costs.
A molded magnet is used, which has a resin portion of 9 to 13% made of thermoplastic plastic such as polyacetal, polypropylene, or polyethylene. FIG. 2 shows a core part 10 in which the permanent magnet 9 prepared in FIG. The magnetic part necessary for a permanent magnet erasing head is made of resin magnet 9, and the non-magnetic part is made of polyamide and polyacetal.

It is made of thermoplastic resin 11 such as polypropylene, polyethylene, polyvinyl terephthalate, etc., and is designed to play a role in this state. However, in this state of the core part 10, it is difficult to attach it to the mechanism to be used.
As shown in FIG. 1, it is necessary to fix the core part 10 to the eraser head lever main body 12. In the present invention, since the core part 10 is insert molded, the shape and dimensions can be stably obtained with high precision, and the eraser A recess 13 that matches the shape and dimensions of the core portion 10 is provided in the hend lever main body 12,
Assembly is performed by press-fitting the core portion 10 into the recess 13.

Effects of the Invention As described above, in the present invention, the core part of a permanent magnet type erasing head in which a permanent magnet using a resin magnet is insert-molded is molded in advance, and a recess that matches the shape of the core part is formed in the main body of the erasing lever. By providing a core part, it is possible to press fit the core part into the recessed part and assemble the erasing head. 2) Since the process of fixing the core part to the erase lever body is now a press-fitting method instead of an adhesive method, quality accuracy (insufficient adhesive strength due to variations in the amount of adhesive applied, adhesive overflow, etc.) is improved. (3) Manufacturing It has a high degree of contribution as it can bring about total cost reduction (approximately 60% reduction in direct cost) due to process efficiency improvement 5 reduction in defect rate, etc.

[Brief explanation of the drawing]

1, 2, and 3 show an embodiment of the method for manufacturing a permanent magnet type erasing head of the present invention, and FIG. 1 shows a core portion in which a resin magnet is insert-molded. Figures 4 and 5 show the process of laminating a permanent magnet molded with a resin magnet with a magnetic material and cutting it into squares; (b)
is the core after cutting (C1 is the radius of the tape sliding surface)
It shows a completed core after fifill processing. 7... Tape sliding surface, 8... Convex portion,
9... Permanent magnet, 10... Core part, 1
1...Resin, 12...Erasing Radre lever main body, 13...Recessed portion. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (2)

[Claims] (1) By preparing a permanent magnet with an R-shape on the tape sliding surface and a convex portion on the lower part, and insert-molding this permanent magnet, the permanent magnet can be held in place at the same time. Manufacturing a permanent magnet type erasing head by molding a core part whose periphery except the R-shaped part is molded with resin, providing a recessed part matching the shape of the core part in the erasing head lever body, and press-fitting the core part into this recessed part. Law. (2) A resin magnet composed of 87-91% magnetic powder and 9-13% resin by weight is used as the permanent magnet material, thermoplastic is used as the resin material, and the R shape of the tape sliding surface is finalized. A method for manufacturing a permanent magnet type erase head according to claim 1, wherein the shape, dimensions, and surface roughness of the finished product are finished during molding.