Magnetic compass with optical encoder

摘要

A magnetic compass is disclosed which is especially adapted for use in automotive vehicles and which is provided with an optical angular position encoder. The housing comprises a cylindrical cup and a hollow cylindrical rim; a compass rotor is disposed in the housing with the magnet in the cup and an encoder disk in the rim. The hollow rim has a base plate defining a vehicle orientation axis and a cover plate. The rotor is provided with a reference position aperture and a plurality of displacement angle apertures disposed in a single circumferential track. The transducer comprises optical transmitters and receivers mounted opposite each other on the plates for detecting the apertures in the encoder disk. Support arms for the compensation coils and the search coil are disposed on the cup opposite the magnet in a predetermined angular location relative to the orientation axis. The housing including support arms, optical apertures and retaining means for the transmitters and receivers are molded as a unitary body. The rotor is a molded body including the magnet holder and encoder disk with provision for magnetizing the embedded magnet.