JPS5930621Y2 - Electromagnetic drive device using sintered magnets - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic drive device using a sintered magnet, and particularly relates to an improvement in the method of fixing the sintered magnet to a stator.

Permanent magnets that make up the stator of movable ring-type electromagnetic drive devices used as electromagnetic drive sources built into cameras, etc. are often manufactured by melt casting or sintering, and plastic molded magnets have also been developed. .

Among these, permanent magnets manufactured by melt casting or sintering can obtain high magnetic force and are therefore more suitable than plastic molded magnets. This requires a polishing process, which increases costs.

On the other hand, plastic molded magnets have good processing accuracy, but as permanent magnets, their magnetic force is weak and they may be unsuitable for use as small electromagnetic drive sources.

The present invention has been made in view of the above points, and proposes an improved fixing method so that a sintered magnet can be used as a stator of an electromagnetic drive device as it is after being formed.

That is, the first method according to the present invention is a method of fixing a sintered magnet to a stator using a fixing member such as rubber or soft plastic material without polishing it.
The method involves inserting a sintered magnet into a mold with a plastic material to ensure external dimension accuracy, and then fixing it to a stator.

By using these methods, the step of polishing the magnet can be omitted, and furthermore, dimensional variations can be absorbed by the fixing member, resulting in cost reduction.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of an electromagnetic drive device according to the present invention.

In the figure, 1 is a cylindrical yoke, and 2 is a permanent magnet formed by sintering.

3 is a movable coil rotatably supported by the output shaft 10;

4 and 5 are fixing members for fixing the magnet 2 to the stator yoke 1, and are made of a soft material such as rubber or plastic.

When attaching the sintered magnet 2 having the shape shown in the figure to the yoke 1 using the fixing members 4 and 5, the variations in the dimensions of the magnet 2 can be absorbed by adjusting the dimensions, mounting positions, etc. of the fixing members 4 and 5. The gap with the yoke can be made uniform.

FIG. 2 is a sectional view showing another embodiment of the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals.

In the figure, 6 is a plastic molded member into which a magnet 2 is inserted, and is constructed integrally with the fixing member.

By inserting the magnet in a plastic molded member in this way, variations in the dimensions of the magnet 2 can be absorbed by the size and shape of the plastic material, and high dimensional accuracy can be achieved by configuring the outer shape of the molded member to the correct dimensions. can be attached to the yoke with an integral fixing member.

Fig. 3 is a perspective view showing the shape of the part after the magnet is inserted into the plastic mold.
A three-way claw or the like is inserted into and 13, and a pin or the like is inserted into 14 and 15 to fix them, and then the malt insert is inserted.

As described above, in the electromagnetic drive device of the present invention, the stator is constructed using sintered magnets as formed, and the magnet polishing process can be omitted, thereby reducing costs and reducing costs. It is possible to absorb dimensional variations and manufacture high-precision compact electromagnetic drive devices at low cost, and is suitable for mass production of compact electromagnetic drive devices suitable as shutter drive sources for cameras and the like.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the electromagnetic drive device according to the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG.
The figure is a perspective view showing the shape of a magnet according to the present invention after being inserted into a plastic mold. 1...Yoke, 2...Permanent magnet, 3.
...Moving coil, 4,5...Fixed member,
6...Plastic mold member, 10...
...Output shaft, 11, 12, 13°14.15...
...Hole for magnet fixing.

Claims (1)

[Claims for Utility Model Registration] 1. In an electromagnetic drive device comprising a fixed field consisting of a permanent magnet and a cylindrical yoke, and a movable coil rotatably supported, the permanent magnet is sintered. It consists of a molded non-polishing member of the magnet, and two fixing members made of rubber or soft plastic are arranged at symmetrical positions around the outer periphery of the permanent magnet.
An electromagnetic drive device using a sintered magnet, characterized in that a permanent magnet is fixed concentrically to a yoke by elastic pressure contact between the inner periphery of the yoke and the outer periphery of the permanent magnet. 2. The fixing member is formed as a part of a plastic mold member into which a sintered magnet is inserted. An electromagnetic drive device using a sintered magnet according to claim 1, wherein the sintered magnet is fixed by press-fitting the plastic molded member into a yoke.