APPARATUS FOR DETECTING MOTION OF MEMBER

摘要

PURPOSE: To detect the motion of a member regardless of the moving speed thereof by providing a sensor with a coil wound around a core of soft magnetic material having poles forming an air gap. CONSTITUTION: A sensor 4 comprises two identical coils 5, 6 wound around a soft magnetic core 7 forming an air gap between the poles of core in the vicinity of a pulse ring 1. Two sensors are previously arranged in the circumferential direction while being spaced apart by a distance shorter than one wavelength and the difference of detection time between two sensors is measured for same signal by means of a process unit. Consequently, accuracy of speed measurement depends on the accuracy of time measurement and the accuracy of distance between two sensors. Measurement accuracy of two parameters can be enhanced definitely as compared with a case where a synchronous pulse ring is manufactured accurately and maintained.