Patent ID: 8310119

Claim:
An electric motor comprising: a drive apparatus that includes: a stator; a rotor that is placed radially inward of the stator and is rotatable relative to the stator; and a shaft that is rotatable integrally with the rotor; a circuit apparatus that is placed on one side of the drive apparatus in an axial direction of the shaft and includes a drive device that drives the drive apparatus; and a motor case that has a partition wall, wherein the partition wall partitions between a drive space, in which the drive apparatus is placed, and a circuit space, in which the circuit apparatus is placed, in the axial direction in the motor case, wherein: the circuit apparatus includes a circuit board; the circuit board is placed at an end part of the circuit space, said end part being spaced apart from the drive apparatus in the axial direction; the circuit board has a circuit board side sensor device that forms a sensor apparatus that senses a rotational angle of the rotor; the shaft has a shaft side sensor device at an end part of the shaft to correspond with the circuit board side sensor device; the shaft side sensor device forms the sensor apparatus in cooperation with the circuit board side sensor device; an outer diameter of the shaft side sensor device is smaller than an inner diameter of a through hole defined through the partition wall, and through which the shaft extend; and the shaft, with the shaft side sensor device at said end part thereof, is configured to be inserted through the through hole of the partition wall and through the circuit apparatus, without disassembling the shaft side sensor device from the end part of the shaft, to place the shaft side sensor device in an opposed relationship to the circuit board side sensor device at a location adjacent to the circuit board side sensor device.