MOUNTING STRUCTURE OF BALL NUT IN MOTOR-DRIVEN STEERING DEVICE

PROBLEM TO BE SOLVED: To provide a caulking structure by which a simple and sure slack prevention for a mounting lock nut is achieved in a ball nut mounting structure of a motor-driven steering device. SOLUTION: The periphery of a ball nut 2 engaged rotatably on a ball screw shank part 1a of a rack bar 1 is fitted in the inner race part 4a of a ball bearing 4, and thereby mounted in such a way as rotatable relative to a housing 10a and not movable in the axial direction of the rack bar 1. The coupling for this mounting is generated by fastening the lock nut 5, whereby the inner race 4a is pinched tightly by the lock nut 5 and a flange 2f on the ball nut 2. The slack prevention of the lock nut 5 is generated by caulking an extended screw portion 5c of the lock nut 5 to a plane part 2e formed on the extension part 2b of the ball nut 2. COPYRIGHT: (C)2005,JPO&NCIPI