| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a helical broach capable of: approximating a side surface of a tooth profile of a workpiece to an involute curve when the tooth profile of the workpiece is cut by outer diameter-increasing blades in the tooth height direction; avoiding biased abrasion occurring on a finishing blade; increasing the life; and accurately finishing the final shape of the tooth profile of the workpiece. <P>SOLUTION: In this helical broach, a plurality of cutting blades projecting radially outward are arranged on the outer peripheral part of a shaft-like broach body in a row so as to be spirally twisted around the axis of a broach body from the distal end side toward the rear end side of the broach body, and so that the row of the cutting blades are arranged at intervals in the circumferential direction. A helical flute with a predetermined lead is formed in the inner periphery of the machined hole of the workpiece by these cutting blades. The plurality of cutting blades on the distal end side of the broach body among the plurality of cutting blades are formed in the outer diameter-increasing blades the tooth heights of which are gradually increased to cut the tooth profile of the workpiece in the tooth height direction. The plurality of cutting blades on the rear end side of the broach body are formed in tooth thickness-increasing blades the tooth thicknesses of which are gradually increased to cut the tooth profile of the workpiece in the tooth thickness direction. <P>COPYRIGHT: (C)2013,JPO&INPIT |
