To prevent the breakown and the rust at the surface part of a magnet and to enhance the efficiency, productivity and economy of a vibrator by constituting the vibrator of a molded film body comprising insulating nonmagnetic material, a nonmagnetic shaft and a rare earth magnet embedded in the molded film body.
A nonmagnetic shaft 14 is arranged at the center of a planar mold. Rare earth magnets 11a, 11b, 12a and 12b, which are the permanent magnets, are arranged at both ends so as to hold the shaft 14. Insulating nonmagnetic raw material is made to flow into the tightly closed mold and hardened so as to form a unitary body. In this way, the surrounding parts of the rare earth magnets 11a, 11b, 12a and 12b are covered by a molded film body 13 comprising insulating nonmagnetic raw material. In this structure, the generation of eddy current can be made zero by the alternating magnetic field generated by a coil. Furthermore, the attracting repelling force developed between the magnet and an electromagnet becomes proportional, and the magnet having the large residual magnetic flux density can be arranged.
MITARAI HIROSHIGE
MATSUOKA HIROSHI
MURATA KOJI
KAWAKUBO TOSHINORI
YAMAGUCHI TAMOTSU
YASUNAGA KK
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