BALL SCREW HAVING SPACER AND INSERTING METHOD FOR BALL OF BALL SCREW AND SPACER

摘要

PROBLEM TO BE SOLVED: To provide a ball screw having a spacer with no fluctuation and the increase of dynamic torque of the ball screw even when there is a difference in a revolving speed during rolling movement of a ball due to unevenness in the shape of the ball rolling groove and both recessed surfaces of the spacer are closely nipped between the spherical surfaces of adjoining balls. SOLUTION: A spherical recessed surface 21 in which a part of the spherical surface of a ball 10 is slidably fitted is formed in the both end faces in an axial direction of a plastic columnar (or disc-form) spacer 20. Coupled with each protrusion end 23, a plurality of protrusions 22 following the spherical surface of the ball 10 are dispersingly formed on the recessed surface 21. Namely, the spherical surface of the ball 10 is rolled with the spherical surface of the ball making point contact with the protrusion ends 23 of the protrusions 22.