JPS5814143B2 - Manufacturing method of rotor for small motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a rotor for a small motor used in a crystal watch, etc., and more specifically to a method for manufacturing a rotor for a small motor used in a crystal watch, etc. This is related.

Permanent magnets commonly manufactured and used in the past include sintered magnets and plastic or rubber magnets.

The most typical sintered magnet is a ferrite magnet, which has excellent magnetic properties as a permanent magnet, and is used in many rotors for small motors of quartz watches.

However, sintered magnets have drawbacks such as very poor dimensional accuracy due to shrinkage during sintering, and the material is very hard and brittle, making it difficult to perform machining to improve dimensional accuracy. This was the most important problem for small watch motors, which required small size and high precision.

On the other hand, flat magnetic anisotropic magnets are also called plastic magnets or rubber magnets because they use plastic, synthetic rubber, natural rubber, or the like as a binder for magnetic powder.

Recently, research and development of this type of magnet has progressed, and it is inexpensive, and many of them can be made into strong permanent magnets in the direction of easy magnetization by giving them magnetic anisotropy. Furthermore, the material is not brittle and is hard enough to be easily machined.

Therefore, if a rotor for a small motor is formed using this flat magnetic anisotropic magnet, it will be possible to create a rotor for a small motor with high precision, at a low cost, and with excellent performance through machining. .

However, due to manufacturing problems, the magnetically anisotropic magnet material has a flat plate shape as shown in the first figure, and has an easy magnetization direction in the thickness direction.

For this reason, if a rotor is made by simply punching out this magnetically anisotropic magnet material in the thickness direction using a press, for example, the rotor will have an easy direction of magnetization in the axial direction. It is not suitable for

When manufacturing a permanent magnet rotor that is magnetically anisotropic in the radial direction from a plate-shaped magnetically anisotropic magnet material whose easy magnetization direction is the thickness direction, the present invention provides a method for forming concave grooves on at least one side of the material. This groove is made to remain in the rotor as a final product, and the remaining groove is used to identify the direction of magnetization during magnetization.

To explain an example, in FIG. 1, reference numeral 1 denotes a magnetic anisotropy material that is thicker than the diameter of the rotor to be the final product, and has an easy magnetization direction 2 in the thickness direction.

Therefore, as shown in the second diagram, both sides of this material 1 (one side is also possible)
Concave grooves 3 are arranged parallel to each other.

The spacing between the grooves 3 is set to be equal to or slightly larger than the thickness of the material 1.

Next, the prism body 4 is formed as shown in the third figure by cutting from approximately the middle position between the concave grooves 3.

Then, the prismatic body 4 is processed into a cylindrical body 5 so that the groove 3 remains on the outer peripheral surface as shown in the fourth figure.

At this time, a center hole 6 is bored in the center.

Finally, the cylindrical body 5 is cut to an appropriate thickness as shown in FIG. 5 to form a disk 7, which is magnetized in the direction of the groove 3.

Note that the center hole 6 can also be formed after the disk 7 is formed.

According to this manufacturing method, concave grooves are arranged in advance at regular intervals on a flat plate-shaped magnetically anisotropic magnet material, and these concave grooves remain until the final product, so that the direction for magnetization can be adjusted. Identification can be performed accurately and quickly, and by introducing automatic processing, large quantities can be processed at low cost and with high precision.

[Brief explanation of drawings]

The drawings relate to a method of manufacturing a rotor for a small motor according to the present invention, and FIG. 1 is a perspective view of a flat magnetic anisotropic magnet material;
Figure 2 is a perspective view of the same material with grooves arranged in parallel, Figure 3
The figure is a perspective view showing the process of cutting the above material into a prismatic body, Figure 4 is a perspective view showing the state in which the above prismatic body is processed into a cylinder, and Figure 5 is a perspective view of the rotor finally obtained. be. 1... Flat magnetic anisotropic magnet material, 2...
...Easy direction of magnetization, 3... Concave groove, 4...
...Prismatic body, 5...Cylindrical body, 6...
Center hole, 7... Disk (rotor).

Claims (1)

[Scope of Claims] 1. Concave grooves are arranged in parallel at regular intervals on at least one side of a flat plate-shaped magnetic anisotropic magnet material whose thickness direction is the direction of easy magnetization, and from approximately the middle position of the adjacent concave grooves. The prismatic body is cut to form a prismatic body, the prismatic body is processed into a cylindrical body leaving the groove on its outer circumferential surface, the cylindrical body is cut to a desired thickness to form a disc, and the disc is shaped into a cylindrical body with the groove. A method of manufacturing a rotor for a small motor, characterized by magnetizing in the direction of.