公开(公告)号：US20180243847A1

公开(公告)日：2018-08-30

申请号：US15904507

申请日：2018-02-26

申请人： NACHI-FUJIKOSHI CORP.

发明人： Hideki SATO ,  Shota MIURA ,  Kazuyuki NAKAMURA ,  Masayuki TSUNO

IPC分类号： B23D43/06 ,  B23F21/26 ,  B23D43/04

CPC分类号： B23D43/06 ,  B23D37/16 ,  B23D43/005 ,  B23D43/04 ,  B23F21/26

摘要： A helical broach which eliminates the need for a fixing means for fixing a workpiece during gear machining is provided. The helical broach includes: a plurality of cutting edges; a spiral flute formed between adjacent cutting edges to extend in a spiral manner with a predetermined helix angle with respect to an axial direction of the helical broach; and a gullet formed between adjacent cutting edges to extend with a predetermined helix angle with respect to a circumferential direction of the helical broach. In the helical broach, the expression: 0.5≤tan β/tan(α+β)≤0.7 is satisfied, wherein β is the helix angle of the spiral flute, and (90°−α) is the helix angle of the gullet with reference to a central axis of the helical broach. An internal gear machining method using the helical broach is also provided.