The difference between gear hobbing and hobbing

Writer： admin Time：2024-04-01 14:24:35 Browse：83℃

     The tooth profile accuracy of gear hobbing is higher than that of hobbing. When hobbing, the number of tangent lines forming the tooth profile envelope is only related to the number of chip grooves in the hob and the number of basic worm heads, and it cannot be increased or decreased by changing the machining conditions; But when inserting gears, the number of tangent lines that form the tooth profile envelope is determined by the magnitude of the circumferential feed rate and can be selected. In addition, when manufacturing gear hobs, a worm with an approximate shape is used to replace the involute basic worm, which results in shaping errors. The tooth profile of the slotting cutter is relatively simple, and precise involute tooth profile can be obtained through high-precision grinding. So gear shaping can achieve high tooth profile accuracy.

    Gear hobbing is the most productive and widely used method in tooth profile machining. The principle of using gear hobs to machine gears on a hobbing machine is equivalent to a pair of helical gears engaging without backlash, as shown in Figure 9-24. The universality of gear hobbing is good, it can process both cylindrical gears and worm gears; It can process both involute tooth profiles and circular arcs, cycloids, and other tooth profiles; It can process both large module gears and large diameter gears.

     Gear hobbing can directly process gears with 8-9 levels of accuracy, and can also be used as a 7-level gear

Rough machining and semi precision machining of gears above grade. Gear hobbing can achieve high motion accuracy, but due to the fact that the tooth surface is formed by the envelope of the hob, the number of teeth participating in cutting is limited, resulting in a coarser surface roughness of the tooth surface. In order to improve the machining accuracy and tooth surface quality of gear hobbing, it is advisable to separate the coarse and fine gear hobbing.