Abstract: A ball screw mechanism comprises a nut, a screw shaft, plural balls and a deflector. The balls are arranged between a first thread groove which is formed on an inner surface of the nut and a second thread groove which is formed on an outer surface of the screw shaft. The deflector comprises a deflector piece which defines a top plate of a ball-return path and a guide member which defines sidewalls of the ball-return path. The ball-return path returns the balls so as to circulate endlessly. As a manufacturing method of the ball screw device, the deflector piece is attached to the nut first. Next, the first thread groove is ground together with an inner surface of the deflector piece. After that, the guide member is attached to the nut. At last, the balls and the screw shaft are assembled to the nut.

Abstract: A ball screw mechanism comprises a nut, a screw shaft, plural balls and a deflector. The balls are arranged between a first thread groove which is formed on an inner surface of the nut and a second thread groove which is formed on an outer surface of the screw shaft. The deflector comprises a deflector piece which defines a top plate of a ball-return path and a guide member which defines sidewalls of the ball-return path. The ball-return path returns the balls so as to circulate endlessly. As a manufacturing method of the ball screw device, the deflector piece is attached to the nut first. Next, the first thread groove is ground together with an inner surface of the deflector piece. After that, the guide member is attached to the nut. At last, the balls and the screw shaft are assembled to the nut.

Abstract: A horizontal machine tool has a spindle head which supports a horizontal tool spindle. The spindle head is guided on a top surface portion of a base such that the spindle head is movable in two horizontal directions X and Z. A workpiece support for supporting a workpiece on its upper end is guided on the vertical front face portion of the base for movement in a vertical direction Y. When the spindle head is located at a machining position at the center in the X direction, a pair of guide portions of each of a front/back guide mechanism for the spindle head and a vertical guide mechanism for the workpiece support body take symmetrical positions with respect to a vertical plane including the axis of the tool spindle. A first index member and a second index member for supporting the workpiece are provided on the workpiece support body. Therefore, all surfaces of the workpiece excepting an attachment surface can be machined while being directed to a tool on the tool spindle.