Flexible ribbed, no-backlash ball nut
First Claim
1. A ball nut, which comprises a body having a head end, a tail end and a connecting section joining said head end and said tail end, said body having an axial bore extending through said body, said connecting section having a substantially helical path track on said axial bore for receiving a plurality of ball bearings for engaging threads of a lead screw, a solid backbone connecting said head end to said tail end, and a plurality of separate rib members attached to said solid backbone and comprising substantially C-shaped segments of a substantially helical shape corresponding to said substantially helical path track, and a return path for said plurality of ball bearings connecting ends of said substantially helical path track.
2 Assignments
0 Petitions
Accused Products
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). The spine (34) provides stiffness for the ball nut (12) and the rib segments (36) flex to compensate for variations in threads (38) of the lead screw (14).
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Citations
15 Claims
- 1. A ball nut, which comprises a body having a head end, a tail end and a connecting section joining said head end and said tail end, said body having an axial bore extending through said body, said connecting section having a substantially helical path track on said axial bore for receiving a plurality of ball bearings for engaging threads of a lead screw, a solid backbone connecting said head end to said tail end, and a plurality of separate rib members attached to said solid backbone and comprising substantially C-shaped segments of a substantially helical shape corresponding to said substantially helical path track, and a return path for said plurality of ball bearings connecting ends of said substantially helical path track.
- 10. In a ball nut having a body with an axial bore having a spiral track for receiving a plurality of ball bearings between the spiral track and threads of a lead screw, the body having a head end, a tail end and a connecting section joining said head to said tail end, the improvement comprising a solid backbone on said connecting section extending between said head end and said tail end, and a plurality of rib sections each connected to said backbone and separated from one another by a plurality of slots.
Specification