| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress fatigue failure of a heading tool, with a simple and low-cost configuration, and to allow continuous use for an extended period, for improved tool life in screw heading with a high strength material. <P>SOLUTION: Inside a heading tool 30, a plurality of hole spaces or a cylindrical groove space 50, which positively promotes elastic deformation of a pressurizing part 30a of the heading tool 30 and reduces a stress amplitude acting on a fatigue failure part of a cross hole formation part at the tip of the heading tool at the time of heading and load elimination under deflection in the pressurizing axis direction, is formed, in parallel to the pressurizing axis, from a pressurizing part end face 30a1 of the pressurizing part 30a of the heading tool to the inside of the pressurizing tool. A packing material 51 having the same shape as the groove space 50 or the plurality of hole spaces is inserted into the cylindrical groove space 50 or the plurality of hole spaces, to positively promote elastic deformation of the pressurizing part 30a of the heading tool. The stress amplitude that acts on the fatigue breakage part of the cross shape hole formation part at the tip of the heading tool at the time of heading and load elimination under deflection is suppressed. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
