Electric motor with discrete circuit board and sensor case

摘要

An electric motor includes a rotor having a field permanent magnet, a board housing member fixed to a stator, and a magnetism detecting circuit that detects the magnetism of the field permanent magnet. The magnetism detecting circuit includes a circuit board that is discrete from the board housing member, a sensor case that is discrete from the circuit board and is supported on the circuit board, and a rotation sensor held by the sensor case. The board housing member has an engagement hole and a positioning surface. The sensor case has an engagement convexity corresponding to the engagement hole and an abutting surface corresponding to the positioning surface. When the circuit board has been located in the board housing member, the engagement convexity engages the engagement hole and the abutting surface abuts the positioning surface, resulting in that the rotation sensor is positioned relative to the board housing member.