ROTATIONAL COUPLING DEVICE WITH FLUX LEAKAGE PATH INSULATOR

摘要

A rotational coupling device is provided that minimizes flux leakage from a magnetic circuit that engages the device. The device includes a rotor and an armature defining opposed engagement surfaces. The rotor, the armature and a field shell disposed on one side of the rotor and housing an electrical conductor comprise members of a magnetic circuit that, upon energization of the conductor, draws the armature into engagement with the rotor. A torque transmission member is coupled to the armature and supported by a bearing. In one embodiment a sleeve is disposed radially inwardly of the bearing. To prevent flux leakage through the torque transmission member, the sleeve has a magnetic permeability that is lower than a magnetic permeability of the members of the magnetic circuit. In another embodiment, a support cup of the torque transmission member has a radially outwardly turned flange to distance the cup from the rotor.