Ball screw polishing method and device thereof

A ball screw polishing method comprising the steps of:

• rotatably retaining a screw shaft of a ball screw and rotating the screw shaft around an axis line when polishing the screw shaft by a polishing tape;
• continuously or intermittently transferring the polishing tape;
• bringing said polishing tape into pressure contact with a ball groove of said screw shaft on an outer peripheral surface of a pressure contacting roll;
• wherein a rotating axis line of said pressure contacting roll is arranged so as to incline in correspondence to a lead angle of said ball groove,
• wherein said polishing tape is transferred and guided in a tangential direction of the pressure contacting roll by a turnback roll,
• linearly oscillating said pressure contacting roll in a tangential direction of the ball groove while being orthogonal to said rotating axis line;
• linearly oscillating said pressure contacting roll in a direction of said rotating axis line toward both inner side surfaces of said ball groove;
• moving said polishing tape to the direction of the axis line of said screw shaft;
• synchronizing a rotating speed of said screw shaft and a moving speed of said polishing tape in correspondence to the lead of said ball groove;
• and
• polishing said ball groove by said polishing tape on the basis of a complex motion of the rotation of said screw shaft, the transfer of said polishing tape, the linear oscillating motion in two directions including the tangential direction of the ball groove and said direction of the axis line toward both the inner side surfaces of said ball groove, and the movement of the polishing tape in synchronization with the rotating speed of said screw shaft.