| 摘要 |
PURPOSE:To detect the number of turns exactly at all times by forming a concave on the outer circumferential surface of the rotary shaft and by providing a detecting part of an electromagnetic detector for detecting the rotation speed so that it can be faced to the concave. CONSTITUTION:The electromagnetic detector 27 contains a detecting head that consists of the core 30 and the coil 31, both ends of the coil 31 are connected to the external terminals 32, 33 respectively. The terminal 32 is grounded through the resistance 34, and is also connected to the wave form shaping circuit 36 through the capacitor 35. The output side of the shaping circuit 36 is connected to the input side of the frequency converter 39 through the capacitor 38, and is connected to the tachometer 41 through the resistance 40. When the rotary shaft 8a turns, magnetic resistance is changed by the core 30 and the rotary shaft 8a every time the air vent 25 formed in the shaft 8a faces to the detecting part 28, resulting in the development of voltage at the external terminal 32. Also the transformer 39 provides a voltage output proportional to the frequency of a pulse emitted by the shaping circuit 36. In this way, the number of turns of the rotary shaft can be detected by the tachometer 41. |
