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作者以模数1.25的小型直齿輪和斜齿輪为例,叙述逆銑、順铣直齿輪和斜齿輪用的滚刀齿頂刃的工作情况,为改进滚刀的形状及設計提供資料。逆銑直齿輪表明:随走刀量加大,刀齿齿頂負荷也将增大,而最大切屑厚度并不成比例增加,同时与大切削厚度的刀齿远离滚刀的創成中心。由于齿頂刃切除的金屬占总切屑量的65%,故磨损集中于齿頂刃,并取决于齿頂圆弧形状。为了減少磨損,作者采用了单一圆弧。逆銑斜齿輪試驗表明:随着齿輪螺旋角增大,最大負荷刀齿更远离創成中心而向切入端移动。滚刀的直徑加大,最大切屑的尺寸有所減小,对大型斜齿輪尤其如此。为了改善滚刀的工作条件,滚刀应具有足够的长度,而切入端应具有一定的錐度。顺铣时,切屑由薄逐渐变厚,切削长度也稍短于逆銑时的切削长度,这些都将有利于滚削效率和刀具耐用度的提高。
Using the example of a small spur and helical gear with a module of 1.25, the author describes the workings of the hobbing cutter with counter-milling, straight-milling spur gears and helical gears, and provides information for improving hob shape and design. Milling straight spur gear shows that with the increase of pick-up, the tooth tip load will also increase, while the maximum chip thickness does not increase proportionally, meanwhile, the cutting teeth with large cutting thickness are far away from the center of the hob. Since the metal removed by the tooth tip blade accounts for 65% of the total chip volume, wear is concentrated on the tooth tip blade and depends on the shape of the tip arc. In order to reduce wear, the author adopted a single arc. The anti-milling helical gear test shows that as the gear helix angle increases, the maximum load tooth moves farther away from the center of creation and into the cutting edge. Hob diameter increases, the maximum size of the chip has been reduced, especially for large bevel gear. In order to improve hob working conditions, Hob should have a sufficient length, and cut into the end should have a certain degree of taper. Downward milling, the chip from the thin gradually thicker, the cutting length is also slightly shorter than the length of the milling cut, which will help improve the hobbing efficiency and tool life.