| 摘要 |
PURPOSE:To reduce magnetic noise which is generated from a motor by bonding and forming two thin plates of a rotary yoke through viscoelastic material and composing one of the plates of a magnetic material. CONSTITUTION:A rotary yoke 10 is not formed of sole thin magnetic material but of at least two thin plates 10-1, 10-2 interposed with viscoelastic material 10-3 in such a manner that they are integrally bonded in a structure. One plate 10-1 is composed of a magnetic material, and the other 10-2 is composed of nonmagnetic material. When thus composed, periodical force of axial direction produced due to the energization of a stator coil 5 vibrates the plate 10-1, but this vibration is attenuated in the material 10-3 in the course of transmitting it to the plate 10-2. Accordingly, the magnetic noise can be reduced. |
