Motor operated power steering device

A motor operated power steering device, comprising:

• a steering shaft;
• a gear fitted around the outer circumference of the steering shaft;
• a steering assistance motor which transmits a rotational force via the gear to the steering shaft;
• and
• a torque limiter, fitted in between the steering shaft and the gear, and having a diametric direction defined by a diameter of the torque limiter;
• wherein:
• the torque limiter includes a torque setting member, which is subject to diametric deformation along the diametric direction as a result of being fitted in between the outer circumference of the steering shaft and the inner circumference of the gear;
• the torque setting member includes a ring with a circumference around which plural projections are spaced and project diametrically;
• the torque setting member causes a diametric force corresponding to its diametric deformation to act on the steering shaft and the gear;
• a limit torque value of the torque limiter, corresponds to the diametric deformation of the torque setting member;
• when the diametric deformation of the torque setting member is less than a specific value, the diametric force increases in proportion to the diametric deformation;
• when the diametric deformation exceeds the specific value, a ratio of increase in the diametric force to the diametric deformation is smaller than when the diametric deformation is less than the specific value;
• and
• the diametric deformation of the torque setting member is a value in a range in which the diametric deformation exceeds the specific value.