Patent ID: 7723873
Filing Date: 2010-05-25
Classification: B06B,H02K

Abstract:
1. A vibration actuator comprising: a moving part having a plate-shaped magnet magnetized in a vibration direction in a housing case, the moving part having a restricted movable range in the vibration direction, a guide shaft onto which the moving part is movably mounted, a field coil, and a coil yoke made of a magnetic material, the field coil and the coil yoke are disposed around an outer surface of the magnet, and the field coil and the coil yoke are to generate a single magnetic pole around a central portion of a vibrational amplitude of the moving part during a period in which a current flows through the field coil, wherein the moving part having the plate-shaped magnet is vibrated by interaction between a magnetic field generated by the field coil and a magnetic field generated by the plate-shaped magnet, the moving part having the plate-shaped magnet includes two cup-shaped magnet yokes made of a magnetic material, each of the magnet yokes has a protrusion protruding radially from an outer circumferential portion of the plate-shaped magnet, and the two magnet yokes formed to interpose the magnet to form a magnetic gap, providing a restriction in the amplitude of the vibration of the moving part by interacting magnetically with the field coil and the coil yoke.