Hobbing gears belong to the generation method, which can be regarded as gear and rack transmission without meshing clearance.When the hob rotates once, it is equivalent to the rack moving one tooth in the normal direction, and the continuous transmission of the hob is like an infinitely long rack moving continuously.When the hob and the hobbing blank are forced to mesh in strict accordance with the transmission ratio of the gear to the rack, the envelope of the hob teeth at a series of positions forms the involute tooth shape of the workpiece.With the vertical feed of the hob, the desired tooth profile can be hobbed.Gear hobbing is the most widely used gear cutting method at present. It can process involute gears, arc gears, cycloidal gears, sprockets, ratchets, worm gears and enveloping worms, and the accuracy can generally reach DIN4~7 grades.At present, the advanced technology of gear hobbing includes:
(a) Multi-head hob hobbing;
(b) Hard tooth surface hobbing technology;
(c) Large gear hobbing technology;
(d) High-speed gear hobbing technology.