The Design of Speed and Position Sensors in Conjunction with Bearings in Automotive Applications

The proliferation of electronic controls in automobiles has spurred developments in RPM and rotational position sensors and their packaging. The authors have developed custom packages of sensor systems for use in several automobile applications (Anti-lock Braking Systems (ABS), automatic transmissions, steering columns and ignition systems). These packages are characterized by (in their preferred configuration) “zero speed” capabilities, high resolution (100's of signals), digital output, -40°C to +150°C continuous temperature service, EMI, voltage spike and reverse voltage tolerance. The attainment of consistently high resolution and accurate signals is attributed to (1) the integration of sensors with bearings, (2) the development of state-of-the-art magnetization procedures in combination with optimal magnet materials and (3) the development of a general design model. All described designs have been tested for conformance with performance specifications. Durability and reliability testing are being performed at the present time.