| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering system and a method for machining a screw gear of the motor-driven steering system of simple constitution and good operability without play. SOLUTION: Both bearing parts 10b of a screw gear 10 of a motor-driven actuator for adjusting the position of a steering shaft are provided with axial slits 10d around the axis, and the effective diameter of an internal threaded hole 10c is formed to have a maximum diameter Rmax with interference added for tightening at a low temperature, at the center part where gear parts 10a are positioned and to have a minimum diameter Rmin to the extent of having no gap at an ordinary temperature, at both ends of the bearing parts 10b, and in the form of gradually changing from the maximum diameter Rmax to the minimum diameter Rmin. |
