Abstract: A ball nut (60) has internal return paths (62) for a pair of parallel helical tracks (64). The return paths (62) are formed by grooves (66) machined into the body of the ball nut (60) from one end of the helical tracks (64) to the other. Return guide covers (68) and return guide inserts (69) are inserted into the ball groove tracks (64) on each end of the tracks. These covers (68) and inserts (69) divert the ball bearings through the grooves (66) and into the opposite end of the circuit formed by the helical tracks (64). The ball bearings (82) are deflected by the return guide insert (69) smoothly in a tangential path from the helical track (64). Thus, no abrupt change in direction for the ball bearings (82) while they are under load is encountered.

Abstract: A ball screw assembly (10) includes a ball nut (12) and a lead screw (14). The ball nut (12) has a construction which provides both a flexiblility comparable to that achieved with a coil spring ball nut design and a stiffness of a solid ball nut body. The ball nut (12) consists of three sections: a head (16), a tail (18) and a connecting section (20). The connecting section (20) contains most of a ball circuit (22) in the form of a helical track (24), along which ball bearings (14) travel as the ball nut (12) and the lead screw (14) rotate with respect to each other. A plurality of separate slots (32) are provided, essentially along the helical track (24) of the ball circuit (22). The slots (32) are interrupted by a solid spine (34) along the length of the connecting section (20). Segments (36) of the connecting section (20) between the slots ( 32) form ribs connected to the backbone or spine (34).