HELICAL BROACH FOR ROUGHING

摘要

A helical broach 1 for roughing includes a cutting tooth part 30 in which n spline teeth 31 are arranged side by side in an axial direction. The spline teeth 31 each include cutting teeth 32 which are arranged at a predetermined helix angle. The cutting teeth 32 each have an acute angle portion and an obtuse angle portion on both sides thereof in a circumferential direction. The cutting teeth disposed on the first to n-1 th spline teeth 31 (S 1 to S n-1 ) in the circumferential direction are each formed in such a way that its height on the acute angle portion side differs from that on the obtuse angle portion side. The cutting teeth (S n ) of the n th spline tooth (S n ) are each formed in such a way that its height stays constant in the circumferential direction.