A Mathematical Model for a Dry Powdered Magnetic Clutch

摘要

A mathematical model was developed for a magnetic clutch. The clutch is an electromechanical device designed to transmit a torque which can be modulated with an electric current. Torque is transmitted through a dry, ferrous powder located between the input and output members. The action of this powder is controlled by a magnetic field. Clutches of this type are produced commercially by Lear, Inc. A physical explanation of the torque-producing mechanism was given, and the output torque was defined in terms of the total flux passing through the powder. The flux produced by a signal current to the clutch is affected by eddy currents, hysteresis and by the the non-constant permeability of the ferrous powder. The eddy current effect can be described by the diffusion equation, and the hysteresis effect by a describing function. The non-constant permeability of the powder is essentially a dynamic effect and is evaluated from the experimental data. Experimental data was given for the clutch, and the correlation between the analytical model and this data was shown. (Author)