Patent ID: 7893578
Filing Date: 2011-02-22
Classification: H02K

Abstract:
1. An electric motor comprising: a stator; a rotor having a field permanent magnet; a board housing member fixed to the stator; and a magnetism detecting circuit detecting magnetism of the field permanent magnet, thereby detecting a rotational position of the rotor wherein: the magnetism detecting circuit includes a circuit board that is discrete from the board housing member while being provided on the board housing member, a sensor case that is discrete from the circuit board while being supported by a side surface of the circuit board located at the rotor side, and a rotation sensor held by the sensor case; the board housing member has an engagement hole and a positioning surface, the engagement hole being defined in a side of the board housing member opposed to the rotor; the sensor case has an engagement convexity which corresponds to the engagement hole of the board housing member and an abutting surface which corresponds to the positioning surface of the board housing member; and when the circuit board has been provided on the board housing member, the engagement convexity engages the engagement hole and the abutting surface abuts the positioning surface from a radial outside of the stator, whereby the rotation sensor is positioned relative to the board housing member.