Patent ID: 8893573

Claim:
A ball screw device, comprising: a) an elongated screw including a helical groove formed therein; b) a nut member including a crew hole formed therein for receiving said screw, and including a helical groove for engaging with said helical groove of said screw, and for forming an endless ball guiding passage between said nut member and said screw, and including two orifices formed in said nut member and communicating with said helical groove of said nut member, said nut member including two apertures formed therein and aligned with said orifices and concentric with said orifices and communicating with said orifices of said nut member respectively, and said orifices including an inner diameter greater than that of said apertures of said nut member for forming a peripheral shoulder between said orifice and said aperture of said nut member; c) a plurality of ball bearing members engaged in said endless ball guiding passage of said ball screw device; d) a ball coupler device including a connecting member, and a plurality of spacers secured to said connecting member for forming a plurality of compartments between said spacers and for receiving said ball bearing members and for coupling said ball bearing members together; and e) a ball return pipe including a U-shaped structure having a central tubular member, and having two ends for engaging into said orifices of said nut member respectively and for engaging with said peripheral shoulder that is formed between said orifices and said aperture of said nut member, and having two curved coupling portions formed between said central tubular member and said ends, and said ball return pipe including a ball return pathway formed therein and communicating with said helical groove and said endless ball guiding passage of said nut member for receiving said ball bearing members; said nut member including a straight fence formed between said orifice and said screw hole of said nut member and formed in said aperture of said nut member for guiding said ball bearing members to move through said ball return pathway of said ball return pipe and said endless ball guiding passage of said nut member and for preventing said connecting member of said ball coupler device from being contacted by and interfering with said nut member, said straight fence of said nut member being on each side of said ball groove so as to form a pair of straight fences that have lengths, respectively, said pair of straight fences being parallel to each other along said lengths of said pair of straight fences, respectively, said straight fence of said nut member including a length (L) ranged between 0.5 and 30 mm.