Patent ID: 8418573
Filing Date: 2013-04-16
Classification: F16H,Y10T

Abstract:
1. A ball-screw spline, comprising: a screw shaft having an outer peripheral surface provided with a helical ball rolling groove; a ball-screw nut formed into a substantially cylindrical shape and threadedly engaged with the screw shaft through intermediation of a first plurality of balls; and a spline nut assembled outside of the ball-screw nut through intermediation of a second plurality of balls, and including an infinite circulation path for the second plurality of balls to freely reciprocate over the entire length of an axial direction of the ball-screw nut, wherein the ball-screw nut comprises a screw portion and an extended portion which are formed integrally with each other with the same outer diameter, wherein the screw portion has an inner peripheral surface comprising wherein the ball-screw nut has an outer peripheral surface provided with a ball rolling groove for the spline nut, the ball rolling groove for the spline nut being formed over a portion of the ball-screw nut corresponding to the screw portion and the extended portion, and wherein the ball rolling groove for the spline nut is formed at a position which does not overlap the ball return path, in a circumferential direction of the ball-screw nut.