Patent ID: 6675669
Filing Date: 2004-01-13
Classification: F16H,Y10T

Abstract:
A ball screw apparatus comprising:a screw shaft whose outer circumferential face is formed with a spiral screw groove; a nut member which is fitted on an outer circumference of the screw shaft and whose inner circumferential face is formed with a ball screw groove opposed to the ball screw groove of the screw shaft; a ball rolling contact way which is constituted by the respective ball screw grooves opposed to each other; a connecting way which is provided in the nut member and which causes one portion and another portion of the ball rolling contact way to communicate with each other; an endless circulating way which is constituted by the connecting way and the ball rolling contact way; and a plurality of balls received in the circulating way, and further comprising a worked portion with a smoothly continuous shape which is formed by grinding a corner portion at a connecting portion between the ball rolling contact way and the connecting way.