Patent ID: 8646568

Claim:
An electric motor assembly which outputs torque based on a first signal from a sensor, the electric motor assembly comprising: a case which is formed in a cylindrical shape and provides an outer shell; a motor which is disposed in the case and is capable of outputting the torque through a shaft; a control unit which is disposed on an axial side of the motor and is disposed in the case, the control unit being capable of controlling the motor based on at least the first signal; a power source interface which is disposed on the case to protrude in a radial outside direction, and is connected with a power source line for supplying electric power to the motor and the control unit; a first signal interface which is disposed on the case to protrude in a radial outside direction, and is connected with a first signal line for transmitting the first signal to the control unit, the first signal interface being disposed on an axial side of the motor where the control unit is disposed; and a second signal interface which is disposed on the case to protrude in a radial outside direction, and is connected with a second signal line for transmitting a second signal for controlling the motor to the control unit, wherein the electric motor assembly is adapted to mesh with a gear in a gear box provided on a steering column, which is a component of a steering system for transmitting a steering torque from a steering wheel on a vehicle; the electric motor assembly is adapted to output assist torque to the steering column via the gear box based on the first signal, which is a torque signal from a torque sensor disposed on the steering column between the steering wheel and the gear box, the torque sensor being configured to detect the steering torque applied to the steering wheel by an operator of the vehicle as the torque signal; the first signal interface and the power source interface are disposed apart from each other by a predetermined distance; the first signal interface has a connecting portion which is connected with a torque signal line extending from the torque sensor along the steering column, and extends toward the motor and the steering column along an axial direction of the case; and the power source interface has a connecting portion which is connected with the power source line, and extends in the axial direction of the case.