| 摘要 |
PURPOSE:To make it possible to finish a hole in a workpiece so that waveness in the inner peripheral surface of the hole and a warp in opening end face are eliminated to finish the hole with a high degree of accuracy, by providing a rotary cutting edge section for finishing the inner peripheral surface of the hole to a predetermined diameter, in the front or rear part of a broach section. CONSTITUTION:The front end of a broach section 12 is inserted into a circular hole in a workpiece, and then the broach section 12 is pulled out from the circular hole by means of a drive source so that involute spline grooves are formed in the inner peripheral surface of the hole. Simultaneously, compressed air is blown into through an air supply port 23 while a polishing grindstone 20 on a rotary cutting edge section 13 is also allowed to pass through the hole. As a result, this circular hole may be finished to a predetermined inner diameter by means of the polishing grindstone 20 on rotation. Thus, no waveness such as a gouge cutter in a broach is formed in the inner surface of the hole, and therefore, a finished surface with a high degree of accuracy may be obtained. Further, there is formed no warp which is caused by the gouge cutter of the broach, in the opening end face of the hole, and therefore, no secondary process is required. |
