Electric linear motion actuator

An electric linear motion actuator comprising:

• an electric motor;
• a linear motion mechanism having a rotation input/output shaft and configured to convert rotary motion of the electric motor to linear motion of a linear motion portion via the rotation input/output shaft;
• and
• a control device configured to control the electric motor, wherein
• the linear motion mechanism and the electric motor are arranged in line along the same axis, which is an axis of the rotation input/output shaft of the linear motion mechanism,
• the electric motor includes a stator and a rotor which are arranged such that directions of magnetic poles thereof for generating interlinkage magnetic flux contributing to generating a torque are parallel to a rotation shaft of the electric motor,
• the rotor has respective torque generating surfaces at both faces in an axial direction of the rotor,
• the stator has a plurality of excitation mechanisms arranged on both sides in the axial direction of the rotor, respectively, the plurality of excitation mechanisms including independent coil groups in such a manner that one or more systems of the independent coil groups are provided for one of the excitation mechanisms in the axial direction, and thus two or more systems of the independent coil groups are provided in total for both the excitation mechanisms in the axial direction, and
• a power supply system configured to independently supply power to the independent coil groups is provided.