Electromagnetic actuator and camera blade driving device

Abstract

An electromagnetic actuator of the present invention includes a rotor that has a cylindrical outer peripheral surface and that is capable of rotating within a predetermined angular range, a magnetizing coil, and a yoke that has an arcuate surface facing the outer peripheral surface, a first magnetic-pole part, and a second magnetic-pole part. The first and second magnetic-pole parts generate mutually different magnetic poles by energizing the coil. The rotor includes a magnetized rotor part that defines the outer peripheral surface of the rotor and that is magnetized to have different magnetic poles in a circumferential direction, a driving pin that is not magnetized so as to rotate together with the magnetized rotor part, and a protrusion part that is protruded in a radial direction from the outer peripheral surface of the rotor and that faces the first magnetic-pole part or the second magnetic-pole part while being magnetized to have the same magnetic pole as the outer peripheral surface of the rotor. According to this structure, the rotor includes the protrusion part that is protruded from the outer peripheral surface of the magnetized rotor part and that is magnetized, in addition to the magnetized rotor part and the driving pin that is not magnetized. Therefore, the surface of the rotor that faces the yoke and that exerts a magnetic action is increased, and hence a desired maintaining force and a driving torque can be obtained.

Dependencies are inferred from the claim text.