Seiko Precision Inc.

Masami Aizawa

Akihiro Ito

Yasufumi Naoi

To provide a rotor magnet which is small in size and provided with high magnetic energy, a rotor magnet is formed by adding a SmFeN magnetic powder to a binder such as a polyaxnide. The SmFeN magnetic powder is provided in a size of about one-tenth that of an NdFeB magnetic powder. Therefore, the density of the magnetic powder in the magnet can be made uniform. Accordingly, there is not any dispersion of the magnetic poles when a number of poles are magnetized and the magnet can be made smaller since the maximum energy product of the magnet is higher than that of an SmCo series magnet.

Rotor magnet, motor and stepping motor

A shaped plastic magnet comprising a shaped body obtained by molding a mixture of an SmFeN magnetic powder with a resin binder into a desired shape, where the surface of the shaped body is subjected to a coating treatment using a phosphate. Preferably, the coating treatment is performed by using a paint containing a phosphate. The shaped plastic magnet may be used as a rotor to be incorporated in motors. The product is highly resistant against corrosion, and provides extended life to motor rotors and the like.

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Chiba-ken, Japan

Masami Aizawa