Patent ID: 8505405
Filing Date: 2013-08-13
Classification: B62D,F16H,Y10T

Abstract:
1. A ball screw apparatus comprising: a screw shaft having a shaft side screw groove formed on an outer peripheral surface thereof; a ball screw nut having a nut side screw groove formed on an inner peripheral surface thereof; a plurality of balls installed in a spiral rotating way formed by facing said nut side screw groove to said shaft side screw groove; and a circulating member mounted on a mounting hole formed in said ball screw nut and forming a returning way to connect one end and the other end of said rotating way, wherein said nut side screw groove includes a connecting area connecting said rotating way to said returning way, wherein said connecting area faced to said mounting hole in said nut side screw groove is machined to substantially eliminate possible steps at a jointing point of said rotating way and said returning way, wherein said ball screw nut has a base portion and an expanding portion, in said base portion a distance from an axis center of said screw shaft to a bottom portion of said nut side screw groove is constant in order to rotate said ball being put between said nut side screw groove and said shaft side screw groove, in said expanding portion said distance is larger than that of the base portion, and said expanding portion includes said connecting area.