| 摘要 |
PURPOSE:To detect movement at high precision and lower a cost, by providing a moving unit with a sensor confronted with a stationary unit, and by sequentially detecting the individual projections of a pectinate section with the sensor when the moving unit is in motion. CONSTITUTION:A stator base metal 11 is formed in the shape of a ring, and on the back side surface, a piezoelectric unit (electrostrictive element) 12 is fitted to compose a stator (stationary unit) 10. On the base metal 11, projections 13 are arranged in the circumferential direction (progressive direction of progressive wave). Besides, a rotor base metal 21 is formed in the shape of a ring having a width smaller than that of the stator base metal 11, and on the back side surface of the metal 21, a slider 22 is fitted to compose a rotor (moving unit) 20. From the rotor base metal 21, internal and external arms 211, 212 project. An internal arm tip section 211a is provided with a luminous element 31, and an external arm tip section 212a is provided with a light receiving element 32, and via a groove 14 between said projections 13, the generated light of the luminous element 31 is received by the light receiving element 32. Then, along with the driving of the rotor 20, said projections 13 are sequentially detected, and the moving speed and the like of a motor can be determined by the number of pulses and the period. |
