Patent ID: 7908938

Claim:
A ball screw module, comprises: a screw shaft having an outer surface provided with a first load rolling groove; a nut member circumferentially disposed around the screw shaft and having an inner surface provided with a second load rolling groove corresponding in position to the first load rolling groove, wherein the first load rolling groove and the second load rolling groove together form a first rolling track; a ball connector capable of moving around in the first rolling track and comprising a plurality of balls and a connector for carrying the balls, the connector comprising: a plurality of intervals whereby the balls are fixed in position and spaced apart; and a first linking strap and a second linking strap for connecting the intervals in series, wherein the first linking strap and second linking strap are spaced apart by a distance; and a circulating device provided to the nut member and formed with a circulating route in communication with the first rolling track, so as to enable the ball connector to pass the circulating route, the circulating route having a first turning section and a second turning section; wherein the circulating device is characterized in that: the circulating route takes a turn at the first turning section and the second turning section in a three-dimensional manner, and the circulating device is formed with a first guiding groove and a second guiding groove for guiding a first linking strap and a second linking strap of the ball connector, wherein the first guiding groove has a radius of curvature greater than a radius of curvature of the second guiding groove when the ball connector passes the first turning section, and the first guiding groove has the radius of curvature smaller than the radius of curvature of the second guiding groove when the ball connector passes the second turning section.