ホブ切り過渡現象の観察と切りくず生成機構の解明: 第4報，舞いツール基礎試験における切りくず生成時の形態とかみ込みの関係

摘要

The degradation of tooth surfaces and the abnormal tool wear sometimes occurs in dry hobbing. This paper investigates the transient phenomenon of chip formation and behavior in simulation tests of hobbing by using a high-speed video camera. The jamming of the chip between the tooth surface and the cutting edge causes scratches on the tooth surface and the chipping of a cutting edge so on. The figures of chips produced by hobbing are classified roughly into the "U", "J" and "I" types. This paper presents findings of the "J" and "I" type-chip movements in flytool simulation tests. The "J" type chip is removed with the two cutting edges both top and a side edge. In the "J" type-chip, a part of end side of the chip produced by the top cutting edge is often jammed into the finished surface by pushing from the chip at the side cutting edge. The "I" type-chip flows from the root to the tip side of the cutting tooth, and the pointed end of the chip is jammed into the space between the finished surface and the relief face of the cutting tooth, in down cut. In up cut, the chip flows to the root side of the rake face, and possibility of jamming is shown as well as the case of down cut.%近年，歯車のホブ切り加工においても作業環境改善を目的として切削油を用いないドライ切削が採用されつつある．しかし，ドライかつ高速度切削のホプ切りでは，生成時あるいは生成後の切りくずの切れ刃と歯面間へのかみ込みによる工具損傷，仕上げ面性状の劣化という間題が頻繁に発生し，切りくずの生成および排出時の挙動がホブの摩耗や創成歯面の性状に影響をおよぼすことが言及されている．