JPS58158009A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To positioning exactly a back core and a front core in the stage of adhering the same, by inserting the back core into a cap and further putting the cap on the front core. CONSTITUTION:A plate of magnetic material 1B at the center of a front core 1 is inserted into the hole 3C of a coil bobbin 3, and the core 1 and a coil 4 are assembled, whereafter a back core 2 is inserted into a cap 6 made of a resin such as PP. The cap 6 is so formed as to have the inside dimensions conforming to the outside shape of the core 2. After the assembly of the core 1 and the coil 4 is mounted to jigs 4, adhesive agents are coated on the tips of the plates 1A, 1B, 1C of the cores 1, and the cap 6 is put on the adhesive coated surface of the core 1 to adhere the core 1 and the core 2. The core 1 and the core 2 are positioned and adhered exactly. The cap 6 prevents the breakage of the cores in the stage of resin molding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head used in a video tape recorder and a method for manufacturing the same, and in particular, in the manufacturing process of an eraser head for a video tape recorder, a back core is bonded to a front core. ζ: At this time, cover the back core with a resin cap, use this cap to position the back core and front core, and use this cap as a reference for positioning in the mold during the resin molding process. A magnetic head that mechanizes the manufacturing process, reduces man-hours, and improves yield by using it as a magnetic head.

The present invention relates to a manufacturing method and an a-air head manufactured by the method.

The core and coil 11 of the erasing head of a video tape recorder as shown in FIG. 1 (an exploded perspective view) are used. That is, in the figure, the core of the magnetic head consists of a front core 1 and a bank core 2, and the front core 1 consists of three magnetic plates IA, IB, and IC. The coil consists of a coil bobbin 3, a winding 4,
The coil body 73 consists of a main body 3A and a terminal block 3B, and two bins 5 are erected on the terminal block 3B.

This magnetic head has a magnetic plate I in the center of the front core 1.
B is inserted into the hole 3C of the coil bobbin body 3A, and after tightly fixed to the bank core 2 at the edge of the magnetic plates IA, IB, and IC, resin is molded on the outside of the core and the coil by injection molding or the like. Manufactured by

Conventionally, this method of manufacturing a magnetic head has had drawbacks as shown in the reduction machine.

■ The edge of the 70-nt core and the back core are glued together by hand, and the front core's magnetic materials IA, IB,
After applying adhesive to the edge of the IC, attach the back core.
Thereafter, as shown in FIG. 2 (0), the core is fixed with a clip 11 and dried in a dryer, but this requires a lot of man-hours since it is done by hand.

■ The positioning of the back core 2 and the front core 1 relies on visual inspection, but there are many product defects due to misalignment (I), and skill is required.

■ Attaching and detaching the clip 11 is troublesome and requires a lot of man-hours.

■ When molding resin on the outside of the core and coil by injection molding, etc., mold the core and coil as shown in Figure 2←)! 12 and further positioned using a press pin 13, which is set so that there is a gap 11i1J between the tip of the pin 13 and the surface of the back core.

If this dimension δ is too large, the core etc. will move during molding, causing variations in product dimensions, so it should be set to about 50 μm. However, due to variations in core dimensions, adhesion of dust, etc., this void dimension may become 0 or a minus number, resulting in damage to the molded core and back core, resulting in poor product yield.

The present invention eliminates the above-mentioned drawbacks of the conventional magnetic head manufacturing method, reduces the number of man-hours, automates the bonding of the front core and bank core, and further improves the bonding process between the C70 front core and the back core and resin molding. The object of the present invention is to provide a magnetic head and a manufacturing method thereof that can prevent product defects.

The present invention uses a cap made of polypropylene-based resin to position the front core and back core, and also uses this cap on the contact surface of the presser bottle. The above objective is achieved by absorbing the

Embodiments of the present invention will be described below based on the drawings. 3 (perspective views) ① to ② and FIG. 4 are diagrams illustrating the steps of adhering the front core and back core in the method of manufacturing a magnetic head according to the present invention. First, the central magnetic plate IB of the front core 1 is inserted into the hole 3C of the coil bobbin 3, and the 70-ton core and the coil are assembled (O% ■→θ in FIG. 3). Next, (α) insert the back core 2 into the cap 6 made of resin such as polypropylene (Fig. 3 ■, @→θ).

The cap 6 has a shape in which side plates are erected on three peripheral edges of a square plate, and the back core 2 is inserted from the peripheral edge where there are no side plates. Since the internal dimension of the cap 6 is very precisely -i to the external dimension of the back core 2, the front core 2 inserted into the cap 6 will not move within the cap 6.

(h) After attaching the assembly of the 70-point core and the coil shown by θ in the figure to the jig 14, the magnetic plate IA%IB of the front core is removed using the dispenser 15.

Apply adhesive to the edge of 10 (Fig. g3 ■→■) (C)
Cover the adhesive coated surface of the front core with the cap 6 (FIG. 3 θ, e→FIG. 4). Since the internal dimension of the cap 6 exactly matches the external dimension of the bonding surface of the front core by +1, the 70 nt core and the bank core are accurately positioned.

(d) Ensure adhesion between the front core 1 and the back core 2 by crimping the cap 6 to the front core with the crimping pin 16 (FIG. 4). Drying in a C(-) dryer.

FIG. 5 is a diagram showing the state of resin molding in the method of manufacturing a magnetic head according to the present invention. In the figure, the core and the coil are placed in a mold 12 and positioned with a presser pin 13, but the air IIJ at the tip of the presser pin 13 relative to the surface of the cap 6 has an arbitrary dimension in the range of 0 to 50μ. The cap 6 is made of resin such as polypropylene and has high elasticity, so it can sufficiently absorb the unevenness of dimensions due to variations in dimensions or the presence of dust, and it can absorb the problem of front moss and back core. There is no need to worry about damage.

The resin cap 6, which is very conveniently used in the above magnetic head manufacturing method 42, does not contribute in any way to the performance of the magnetic head, but its presence does not adversely affect the performance. It is incorporated into the product as is without being removed. This is because the manufacturing cost of the cap 6 is low, but the labor cost for removing it is rather high.

As described above, in the manufacturing process of the magnetic head, the present invention uses a cap made of resin such as polypropylene, and uses it as a reference surface for positioning the back core and the 70-point core and for resin molding. It has many excellent effects.

■ By inserting the back core into the cap and then placing the cap over the 7-inch core, the positioning of the back core and front core can be done accurately and extremely easily, and can be automated without manual intervention. be.

■ Since it can be automated using a jig, a dispenser or the like can be used to apply the resin, making it possible to achieve uniform coating.

■ Product defects in the process of bonding the back core and front core are reduced, improving yield.

■ Eliminates core damage during resin molding, improving yield.

(2) In short, the manufacturing cost of the magnetic head can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of the core and coil of an erasing head for a video tape recorder, Fig. 2 ■, @ is a diagram showing the drawbacks of the conventional magnetic head manufacturing method, Fig. 3 Φ to ■ and FIG. 4 is a diagram illustrating the steps of adhering a front core and a back core in the method of manufacturing a magnetic head according to the present invention, and FIG. 5 is a diagram showing a state of resin molding. 1.Fist: front core, IA, IB, IC...magnetic plate, 2...-back core, 3...coil bobbin, 3A...@tatami body, 3B...terminal block , 3C...
... hole, 4 ... winding, 5 ... terminal pin, 6 ...
...Cap, 11...Clip, 12.Book, Φ forming machine, 13...Press bottle, 14@-...Jig, 15
@-...Dispenser, 16...ΦCrimp bottle Patent applicant Tokyo Denki Kagaku Kogyo Co., Ltd. Agent Patent attorney Tsuka Moto Daisanbe

Claims (2)

[Claims] (1) In a magnetic head formed by molding resin by an injection molding method or the like on the outside of the coil and the coil (a front core with two threads and a bank core bonded to the negative end face of the front core), the above-mentioned A magnetic head characterized by having a resin cap attached to the surface of the back core opposite to the adhesive surface of the front core. (2) In a method of manufacturing a magnetic head, the front core is passed through a coil, a back core is bonded to the negative end face of the front core, and then resin is molded on the outside of the front core, coil, and bank core by injection molding or the like. , a magnetic head characterized in that the front core and the back core are bonded according to the steps (α) to (−) described below, and the resin cap described later is used as a positioning reference during the injection molding method, etc. Manufacturing method - (a) Insert the bank core into the resin cap <b) Apply adhesive to the - end face of the front core. (C) Insert the resin cap with the bank core inserted.
Place the resin cap over the adhesive-applied side of the front core.