JPS6447910A - Magnetic type rotary angle detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a compact rotary angle detecting apparatus characterized by a simple constitution and high resolution, by forming slit shape opening parts in a superconductive disc at an equal interval. CONSTITUTION:A superconductive disc 14 is vertically fixed to a rotary shaft 11 of a rotary body 13. Slit shaped opening parts 15 are formed in the circumferential direction with the shaft 11 as a center at an equal interval. A magnet 16 generates a magnetic field (magnetic flux 23) so as to penetrate through one or more opening parts 15 in the direction of the shaft 11. A magnetoresistance element 17 detects the change in intensity of the magnetic field, which penetrates through the opening part 15. The magnetic field, which is generated from the magnet 16, is shielded at parts other than the opening parts 15. The magnetic field penetrates only through the opening parts 15 and it is detected with the element 17. The magnetic field, which is detected with the element 17, is changed periodically by the rotation of the disc 14. Therefore, the rotary angle of the rotary body 13 can be detected by counting the period of the output signals of the element 17. Since the opening parts 15 can be formed by the photoetching of the disc 14, the pitch between the opening parts can be made to be about 100mum, and high resolution can be readily obtained.