The constant permanent magnet coupler is composed of two symmetrical disc structures, which can change the output torque by adjusting the air gap between the conductor rotor and the permanent magnet rotor in a small range, so as to realize the torque transmission between the motor and the load. The driving end and the driven end are each composed of two hubs with clearance fit for easy installation. They are connected to the motor shaft and the load shaft by a locking disc, and do not require any keyway or pin for fixing.
When the load exceeds a certain torque limit value, the magnetic induction force will produce an axial repulsive force to enlarge the air gap, so that the load is completely separated from the motor, and the motor is protected from damage.