Design Procedure for Hysteresis Couplers

The present paper is devoted to the description of a procedure for the design of rotational hysteresis couplers for customer applications. The analysis has been oriented towards configurations characterized by high reliability and adaptability to the operating conditions. The tradeoff analysis leads to a claw pole configuration powered by an electromagnet in tandem with a permanent magnet to allow the regulation of the coupling torque and to assure a minimal amount of torque transmission when the power supply of the coupler fails. Moreover, the claw pole configuration seems to be the most promising for the automotive field due to its mechanical simplicity and magnetic efficiency. Unfortunately, the complexity of the magnetic circuit demands a three-dimensional numerical analysis that in the present paper is solved by the finite integrate technique. A design procedure based on this numerical analysis and on the hysteresis characteristics of the magnetic materials has been developed. Moreover, a parameter sensitivity analysis has been carried out to an optimized hysteresis coupler which satisfies the application requirements. In conclusion, the design procedure has been validated considering the experimental results obtained on a prototype of the claw pole hysteresis coupler.