Production methods and the ball screw nut for the ball screw

Even if the axial dimension to produce a longer inner diameter is small nut, without damaging the mold, a recess forming a ball return path, a method of directly formed by plastic working on the inner peripheral surface of the nut material . By a press method using materials and holder (2) a mold having a cam driver (6) cam slider and (7,8) of the tubular member (5), the inner peripheral surface of the nut material (1) (11) S forming a shaped recess (15, 16). Cam driver (6) has an inclined surface having the same inclination as the inclined surface (71, 81) of the cam slider (7, 8) (61b, 61d). The cam slider (7, 8) is, S-shaped convex portions corresponding to the S-shape recess (15, 16) have a (73, 83), held in the through hole of the tubular member (5) (52, 53) It is. Pressing from above a cam driver (6) is multiplied by the pressing pressure, the cam slider (7, 8) moves radially outward, respectively, the inner circumferential surface of the S-shaped protrusions (73, 83) is a nut element (1) (11) press to plastically deform.