Patent ID: 8196486
Filing Date: 2012-06-12
Classification: F16H,Y10T

Abstract:
1. A ball screw mechanism comprising: a screw shaft provided with a male screw groove on an outer circumferential surface thereof; a nut disposed so as to surround the screw shaft and provided with a female screw groove on an inner circumferential surface thereof; and a plurality of balls disposed so as .to freely roll along a rolling path formed between both the opposing screw grooves; wherein one of the screw shaft and the nut comprises a circulating portion connected to the screw groove of said one of the screw shaft and the nut to circulate the balls from one end to the other end of the rolling path, wherein the screw groove of said one of the screw shaft and the nut extends, from the one end to the other end of the rolling path, within a range of not more than 360 degrees round an axis of the screw shaft or the nut, and a sectional shape thereof taken at right angles to the screw groove includes a circular arc portion of 90 degrees or less and a connecting portion which connects to the circular arc portion at a bottom of the screw groove, and wherein the connecting portion extends from the bottom of the screw groove toward an axial end of the ball screw mechanism such that, when observed in an axial view, the connecting portion does not overlap the circular arc portion.