Patent ID: 8789436

Claim:
A ball screw device comprising: an elongated screw including a helical groove formed therein, a nut member including a bore formed therein for receiving and engaging with said screw, and including a helical groove aligned with said helical groove of said screw for forming an endless ball guiding passage between said nut member and said screw, said nut member including a first end portion, and including a barrel provided and extended on said first end portion of said nut member and having an outer diameter smaller than that of said nut member for forming a peripheral surface in said nut member, and including an outer peripheral recess formed in said nut member, a plurality of bearing members engaged with said endless ball guiding passage between said nut member and said screw, a plurality of first bearing elements engaged with said outer peripheral recess of said nut member, a sleeve including a chamber formed therein for receiving and engaging with said nut member, and including an inner peripheral protrusion extended radially and inwardly into said chamber of said sleeve, said inner peripheral protrusion including an inner diameter greater than that of said nut member for allowing said first bearing elements to be received and engaged between said sleeve and said nut member, and said sleeve including a first curved side surface and a second curved side surface formed on said protrusion, said first curved side surface of said sleeve being engaged with said first bearing elements for anchoring and retaining said first bearing elements between said inner peripheral protrusion of said sleeve and said peripheral recess of said nut member, a tubular member including a compartment formed therein for receiving and engaging with said barrel of said nut member and for engaging onto said barrel of said nut member, and including an outer peripheral depression formed therein, and a plurality of second bearing elements engaged with said outer peripheral depression of said tubular member, and said second curved side surface of said sleeve being engaged with said second bearing elements for anchoring and retaining said second bearing elements between said inner peripheral protrusion of said sleeve and said tubular member.