Patent ID: 6053046
Filing Date: 2000-04-25
Classification: F16C

Abstract:
A rotational speed detector for detecting a rotational speed of a wheel mounted on a rotatable axle of a vehicle, said axle being supported by a bearing and comprising an outer structure fixedly mounted on a body of said vehicle and an outer end covered by a cover mounted on said outer structure, said rotational speed detector comprising:a sensor device molded with resin integrally with said cover, said sensor device comprising a magnet and an electromagnetic coil;a rotor mounted on said rotatable axle, said rotor comprising a cylindrical surface facing said sensor device and spaced from said sensor device so as to create an air gap therebetween, said cylindrical surface comprising a plurality of alternating pillars and windows arranged along a rotational direction of said rotor;a magnetic circuit formed by said sensor device and said rotor; andtwo magnetic switches forming part of said magnetic circuit, said two magnetic switches simultaneously switching between closed and opened states in response to a rotation of said rotor, and generating a rotational speed signal in said electromagnetic coil.