JPS6311896Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic drive device, and more particularly to a moving coil type electromagnetic drive device used for positioning a magnetic head of a magnetic disk drive.

As a positioner for the magnetic head of a magnetic disk device, a moving coil type electromagnetic drive device called a voice coil type motor is generally used.

First, a conventional electromagnetic drive device of this type will be explained based on the drawings.

FIG. 1 is a side view of a conventional electromagnetic drive device, FIG. 2 is a cross-sectional plan view taken along the line A-A in FIG. 1,
FIG. 3 is a perspective view showing a state in which a shot ring is fixed to a center pole.

1 to 3, 1 is an E-shaped flat yoke forming an E-shape, 2 is a center pole of the E-shaped flat yoke 1, 3 and 3a are side yokes of the E-shaped flat yoke 1, and 4 is the counter yoke,
5 is a moving coil. 6 is a shot ring fixed to the center pole 2, 6a, 6
b is a ring piece 7 constituting the shot ring 6;
and 7a are side yokes 3 and 3, respectively.
It is a permanent magnet fixed to a.

A magnetic gap is formed between the permanent magnets 7 and 7a and the center pole 2.

The disadvantage of the above-mentioned conventional electromagnetic drive device is that the mechanically fragile permanent magnets 7, 7a are exposed, and the side yoke 3,
3a, there is a drawback that the permanent magnets 7 and 7a are easily cracked, chipped, and scattered. Also, if the permanent magnets are large in size, powder metallurgy technology is required to prevent cracks from occurring. It is difficult to form the permanent magnets 7 and 7a in one piece, and usually they are divided into several parts, but with this type of division, a gap is created between the dividing surfaces and the magnetic flux density distribution is disturbed. There is also the drawback of storing it away.

In addition, when fixing the shot ring 6 to the center pole 2, as shown in FIG.
is glued to the center pole 2, and the corresponding successor 8 is soldered. For this reason, the adhesive and plating of the shot ring 6 may deteriorate, the appearance may be defective, and the number of manufacturing steps is large.

The present invention eliminates the above-mentioned drawbacks; there is no disturbance in the magnetic flux density distribution, there is no cracking, chipping, or scattering of the permanent magnet fixed to the center pole, and there is no deterioration of the plating of the shot ring and the appearance The object of the present invention is to provide an electromagnetic drive device that is free from defects and requires relatively few man-hours to manufacture.

The present invention is characterized by an electromagnetic drive device in which a permanent magnet is fixed to the side yoke of an E-shaped flat yoke, a shot ring is fixed to a square center pole, and a moving coil is arranged in a magnetic gap around the center pole. In the electromagnetic drive device, a protective member is provided on the surface of the permanent magnet, and the shot ring is formed by fixing a rectangular drawn pipe to the center pole and then plating it.

Embodiments of the present invention will be described below based on the drawings.

Here, FIG. 4 is a side view of the electromagnetic drive device according to one embodiment, and FIG. 5 is a perspective view showing a state in which the shot ring is fixed to the center pole.

In this figure, the same reference numerals as in FIGS. 1 to 3 indicate equivalent parts. 9 and 9a are permanent magnets fixed to the side yokes 3 and 3a, respectively, and 10 and 10a are permanent magnets 9, respectively.
and a protective member made of, for example, a thin metal plate such as an iron plate, which is fixed to 9a with an adhesive. 11 is
After applying solder, the shot ring is made of a rectangular drawn pipe and is attached to the center pole 2 as shown in Figure 5.
After being inserted into the holder and heated and pressure welded, finishing processing and plating were applied. In addition, permanent magnets 9, 9a
Although not shown, it is divided into several parts.

As explained above, the electromagnetic drive device according to this embodiment has protective members 10 and 10a made of thin metal plates fixed to the permanent magnets 9 and 9a fixed to the side yokes 3 and 3a of the E-shaped flat yoke 1, respectively. Therefore, cracks, chips, and scattering do not occur in the permanent magnets 9, 9a, and the magnetic flux density distribution can be made uniform.

The shot ring 11 fixed to the center pole 2 is made of a rectangular drawn pipe, and after applying solder to the inner surface thereof, it is inserted into the center pole 2, heated and pressure welded, and then finished and plated. Therefore, since the final step is plating, there is no deterioration of plating due to heat or poor appearance, and the number of manufacturing steps is small.

Further, since there is no joint in the shot ring 11, the impedance can be made smaller than that of the conventional one.

In addition, in this embodiment, the E-shaped flat yoke 1
Although the protective members 10 and 10a of the permanent magnets 9 and 9a fixed to the side yokes 3 and 3a are made of thin metal plates, they may be coated with an epoxy resin having a heat resistance temperature of about 130° C. to a thickness of about 0.1 mm.

As described above, the present invention prevents the permanent magnet fixed to the side yoke of the E-shaped flat yoke 1 from cracking.
There is no chipping or scattering, and there is no deterioration of the plating or appearance defects due to the heat of the shot ring that is fixed to the center pole.Furthermore, the number of manufacturing steps is small, and in particular, there is no eraser (magnetic The present invention is expected to provide an electromagnetic drive device that can prevent stored information from being erased due to magnetic powder adhering to the disk, and can be said to be a device with excellent practical effects.

[Brief explanation of the drawing]

Figure 1 is a side view of a conventional electromagnetic drive device;
The figures are a cross-sectional plan view taken along the line A-A in Fig. 1, Fig. 3 is a perspective view showing a state in which the shot ring is fixed to the center pole, and Fig. 4 is an electromagnetic drive device according to an embodiment of the present invention. FIG. 5 is a side view and a perspective view showing a state in which the shot ring is fixed to the center pole. 1... E-shaped flat yoke, 2... Center pole, 3, 3a... Side yoke, 9, 9a... Permanent magnet, 10, 10a... Protective member, 11... Shot ring.

Claims (1)

[Claims for Utility Model Registration] (1) A permanent magnet is fixed to the side yoke of an E-shaped flat yoke, a shot ring is fixed to a square center pole, and a moving coil is arranged in the magnetic gap around the center pole. An electromagnetic drive device characterized in that a protective member is provided on the surface of the permanent magnet, and the shot ring is formed by fixing a rectangular drawn pipe to the center pole and then plating it. (2) The electromagnetic drive device according to claim 1, wherein the protective member provided on the surface of the permanent magnet is made of a thin metal plate. (3) The electromagnetic drive device according to claim 1, wherein the protective member provided on the surface of the permanent magnet is made of epoxy resin.