Design method of rake face of multi-head double-conical-surface double-enveloping ring surface worm gear hob

The invention discloses a design method of a side rear angle surface of a toroidal worm gear hob, and belongs to the field of mechanical transmission. One spiral body of the multi-head double-conical-surface double-enveloping ring surface worm gear hob comprises N cutter teeth, wherein N is a positive integer. The design method comprises the following steps: determining the position of a straight flute rake face of at least one cutter tooth in N cutter teeth on a spiral body of the multi-head basic worm; determining a centripetal vector of the straight flute rake face of at least one cutter tooth based on the position of the straight flute rake face; the straight groove rake face of at least one cutter tooth is rotated by a first angle around the respective centripetal vector, and a spiral groove rake face of at least one cutter tooth is obtained; and at least one cutter tooth on one spiral body is configured to form a circumferential angle equal-interval array around the axis of the hob ...