| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw-shaped tool in which a meshing length of a tooth flank is surely secured by suppressing shear drop of a tooth tip of a gear to be worked. SOLUTION: The screw-shaped tool is provided in which, on the outer periphery of a base metal 1 to be rotated around a center axis, a screw-shaped part 2 that is helically twisted around the center axis is formed and, on the surface of the screw-shaped part 2, abrasive grain is fixed by a metallic plated layer and an abrasive grain layer 4 is formed. In a valley between screw threads 3 which are adjacent in the center axis direction of the screw-shaped part 2, an extended face 11 is formed that is extended from the apex of the abrasive grain layer 4, for which a slope 7 of the screw thread 3 in the base metal 1 is extended from the apex of the abrasive grain layer 4 formed on top 5 of the screw thread 3 to the valley bottom side of the valley 6 beyond the region of a cutting tooth height D of the screw-shaped part 2. Then, the width e in the radial direction for the center axis of this extended face 11 is set≥0.6 mm. COPYRIGHT: (C)2012,JPO&INPIT |
