环面蜗轮滚刀螺旋槽前刀面设计及修正方法

为提高环面蜗轮滚刀的切削性能及滚齿效率，将滚刀的容屑槽设计成螺旋槽，减小刀齿两侧前角的绝对值，均衡两侧刃的切削条件。根据齿轮啮合理论和环面蜗杆成形原理，以滚刀基本蜗杆分度环面螺旋线的导程角和前刀面曲线的导程角互余为依据，提出一种由圆柱产形面变传动比展成环面蜗轮滚刀螺旋槽前刀面的方法；计算得到滚刀分度环面处的前角近似为0°，而刀齿左侧的前角从齿顶到齿根由正值变为负值，右侧前角从齿顶到齿根由负值变为正值，并且正前角和负前角的绝对值较大。进一步对滚刀前刀面进行修正，将修正后的滚刀模型导入VERICUT软件中，测量其前角，验证设计方法的正确性。结果表明，该方法能够解决滚刀两侧前角绝对值较大的问题，各刀齿左右两侧的前角控制在-0.6°~0.5°之间。

Design and correction method of spiral flute rake face of an hourglass worm gear hob

To improve the cutting performance and hobbing efficiency of an hourglass worm gear hob, it is necessary to design the flutes of the hob into spiral groove, reduce the absolute value of the rake angle on both sides of the cutting teeth, and equalize the cutting conditions on both sides of the blade. Based on the hourglass worm forming method and the gear meshing theory, a method for developing a helical groove with a cylindrical generating surface by changing the transmission ratio is proposed, and the idea behind the method is to ensure that the lead angles of the worm helix and the rake face curve are complementary in any cross section of the basic hob worm. The rake angles on the indexing cycle were both approximately zero, while the rake angles on the left side of the cutting tooth varied from positive to negative from the tooth top to the tooth root, and the rake angles on the right side of the cutting tooth varied from negative to positive from the tooth top to the tooth root. And the absolute values of positive and negative rake angles were larger. The rake face of the hob was further modified, and the modified hob model was introduced into the VERICUT software. The rake angles were measured to verify the correctness of the design method. The results show that the method can solve the problem that the absolute value of the rake angle on both sides of the hob is relatively large, and the rake angles on both sides of the cutting teeth are controlled between -0.6° and 0.5°.