Power assist apparatus

A power assist apparatus comprising:

• an electric motor;
• a speed reducer configured to increase a torque generated by the electric motor;
• an annular torque sensor configured to detect a torque input from a steering wheel to a steering shaft attached to the steering wheel;
• a housing in which the speed reducer and the torque sensor are arranged;
• and
• an annular center aligning bracket,
• wherein the housing comprises a first housing element and a second housing element,
• wherein one of the first housing element and the second housing element is made of a synthetic resin,
• wherein the center aligning bracket is fixed to said one of the first housing element and the second housing element by insert molding such that the center aligning bracket is concentric to said one of the first housing element and the second housing element, and
• wherein the first housing element and the second housing element are joined such that the first housing element and the second housing element are engaged with each other in an axial direction of the torque sensor via the center aligning bracket.