CAR SPEED SENSOR

摘要

PURPOSE:To obviate giving adverse influence upon a car speed sensor in spite of elevation of oil to high temp to cause atomization by constituting said sensor by the use of an optical fiber and containing the sensor in a hermetic casing. CONSTITUTION:A rotary disc 4 is connected to a revolving shaft 2 revolving according to the rotating speeds of a car wheel and a magnet 5 is mounted onto the disc 4. A magnet 10 is mounted to a shielding disc 7 contained in a casing 8 oppositely to the disc 4 and the disc 7 is rotated in the absence of contact. Optical fibers 12 and 13 of which the end faces are placed opposite to each other in a way as to sandwich said disc 7 are mounted to the casings 8, and slits are formed to the disc 7 in such a way as to disconnect and connect the projected light between the end faces of the fibers 12 and 13.