Patent ID: 6043643
Filing Date: 2000-03-28
Classification: F16C,G01P

Abstract:
An encoder device for detecting the rotational speed of a rotating member, the encoder device comprising:an annular active part formed from a plasto-magnet and provided with an active region, the active region being positioned at an outer face of the active part so as to travel past a sensor for detecting the active region, andtwo annular reinforcing elements arranged in contact with the active part, one annular reinforcing element being positioned on either side of the active region so as to leave a portion of the active region exposed to the sensor, and each annular reinforcing element having a cylindrical portion extending over a portion of the outer face of the annular active part so as to be capable of taking up internal radial loadings generated in the active part during rotation of the active part, wherein the annular reinforcing elements are made of non-magnetic material and have an elastic modulus which is high compared with an elastic modulus of the active part and a coefficient of expansion which is low compared with a coefficient of expansion of the active part.