MOTOR FOR ELECTRIC POWER STEERING DEVICE

摘要

Provided is a motor for an electric power steering device of rack-assist type, which is arranged coaxially around a rack shape connected to a steering wheel, thereby to feed a steer assisting force to the rack shaft. In this electric power steering device motor, the ratio (R : Bm) of the ratio (R = tac/ts) between the thickness size (ts) of a rotor shaft (22) in the radial direction and the thickness size (tac) of a rotor core (23) in the radial direction at a portion where a magnet holder (26) is arranged : the effective magnetic flux quantity (Bm) per unit length of a magnet (24) is set at 1 : 5 to 6. Moreover, the ratio (R = tac/ts) is set at 0.4 to 1.6.