Modeling of Electromagnetic Friction Clutches Considering Air Gap and Deflection

The fast response, compact form, and high torque capacity of electromagnetic clutches have enabled their widespread use in industrial applications. However, their torque characteristics exhibit significant nonlinearities, such as dead zones and hysteresis. In addition, as torque is transmitted through friction, friction material wear alters the air gap between the friction surface and armature over time. These factors make the precise torque control of electromagnetic friction clutches challenging, and relatively few studies have addressed this issue. This study proposes a surface deflection model that accounts for installation misalignment and axial elastic deformation. Experimental results reveal that axial elasticity is the primary reason for the dead zone in transmitted torque. The proposed model contributes to a better understanding of the nonlinear behavior of electromagnetic friction clutches and provides a foundation for the development of new methods to control torque.