| 摘要 |
<P>PROBLEM TO BE SOLVED: To elongate the lifetime of a helical broach by making a side surface of a workpiece tooth profile approach an involute curve when the tooth profile of a workpiece is cut to a tooth height direction by a diameter increasing blade so as to avoid generation of partial wear on a finishing blade. <P>SOLUTION: Among a plurality of cutting blades, a plurality of cutting blades on the broach body edge side are made to be outer diameter increasing blades with their tooth height gradually increased so as to cut the tooth profile of a workpiece to the tooth height direction. A plurality of cutting blades on the broach body rear end side are made to be tooth thickness increasing blades with their tooth thickness gradually increased so as to put the tooth profile of the workpiece to the tooth thickness direction and cut the tooth profile to form the involute curve. Side blades 6aa, 6ba, ..., 6ga on the obtuse angle side of the outer diameter increasing blades are formed to be misaligned shapes so that a biased quantity to the outside can be gradually increased as the side edges go to the tooth height direction with respect to the involute curved surface Ia, when a plurality of the aligned outer diameter increasing blades 6a, ..., 6g are laminated in the tooth height direction. <P>COPYRIGHT: (C)2012,JPO&INPIT |
