Patent ID: 6941831
Filing Date: 2005-09-13
Classification: F16H,Y10T

Abstract:
1. A ball screw apparatus comprising: a screw shaft including a spiral-shaped screw groove defined in an outer peripheral surface thereof; a ball nut loosely fittable with the screw shaft and including a screw groove defined in an inner peripheral surface thereof so as to correspond to the screw groove of the screw shaft, the ball nut comprising a nut main body forming a ball circulation hole penetrating through the nut main body in the axial direction thereof, and at least an end cap fixed to an end portion of the nut main body and forming a ball circulation R portion by collaborating with the end face of the nut main body, and the ball circulation R portion allowing the ball circulation hole and the screw groove to communicate with each other; and a large number of balls rollably interposed between both of the screw grooves, the ball circulation hole and the ball circulation R portion. wherein the nut main body defines a guide groove for the balls so that the guide groove is defined on the end face sides thereof and wherein the surface of the end cap opposed to the end face of the nut main body is defined substantially uniform in shape over the entire periphery thereof.