Thread forming tap for ballscrew

A ballscrew thread forming tap comprising a complete thread portion and a leading portion which is provided to be contiguous with the complete thread portion and which has a diameter reduced in a direction toward a distal end of the ballscrew thread forming tap, such that the complete thread portion and the leading portion are provided with an external thread having a semi-circular cross-sectional shape, wherein the ballscrew thread forming tap is to be screwed into a prepared hole provided in a workpiece, so as to cause an inner circumferential surface of the prepared hole to be plastically deformed for thereby forming a ballscrew thread corresponding to the external thread provided in the complete thread portion,

• wherein a screw thread of the external thread has a leading flank and a trailing flank, which are to be positioned on a front side of the trailing flank and on a rear side of the leading flank, respectively, when the ballscrew thread forming tap is screwed into the prepared hole,
• wherein the screw thread is formed such that, in the leading portion, an indentation depth into the workpiece made by the leading flank is smaller than an indentation depth into the workpiece made by the trailing flank, and
• wherein a pitch of the screw thread in a part of the leading portion is larger than a pitch of the screw thread in the complete thread portion.

A ballscrew thread forming tap comprising a complete thread portion and a leading portion which is provided to be contiguous with the complete thread portion and which has a diameter reduced in a direction toward a distal end of the ballscrew thread forming tap, such that the complete thread portion and the leading portion are provided with an external thread having a semi-circular cross-sectional shape, wherein the ballscrew thread forming tap is to be screwed into a prepared hole provided in a workpiece, so as to cause an inner circumferential surface of the prepared hole to be plastically deformed for thereby forming a ballscrew thread corresponding to the external thread provided in the complete thread portion,

• wherein a screw thread of the external thread has a leading flank and a trailing flank, which are to be positioned on a front side of the trailing flank and on a rear side of the leading flank, respectively, when the ballscrew thread forming tap is screwed into the prepared hole,
• wherein the screw thread is formed such that, in the leading portion, an indentation depth into the workpiece made by the leading flank is smaller than an indentation depth into the workpiece made by the trailing flank, and
• wherein a pitch of the screw thread in the leading portion is increased as viewed in a direction toward a distal end of the leading portion.