| 摘要 |
PURPOSE:To make a rotation by external force during an OFF period freely and reduce the price of an apparatus by providing an electromagnetic clutch where a stator and a rotor constitute a magnetic circuit. CONSTITUTION:An ultrasonic motor is composed of a stator 1, a comb teeth part 2 provided in said stator and a piezoelectric ceramic 3 for oscillating the stator 1, a fixed stand 4, a rotor 5 facing the stator 1 and its output shaft 6, and a bearing 7. In this case, a clutch coil 9 is provided between the stator 1 and the rotor 5. If electric current is applied to this clutch coil 9, the stator 1 and the rotor 5 become a field core and an armature core respectively, and a magnetic flux flows through a magnetic circuit passing the stator 1, the comb teeth part 2 and the rotor 5 to attract the stator 1 and rotor 5 and apply a pressurizing force between them. Further, if a current application to the coil 9 is stopped, said magnetic flux disappears and the pressurizing force between the stator and rotor also vanishes so that the rotor 5 can be rotated freely. |
