Processing characteristics of gear hobbing and hobbing

Writer： admin Time：2024-08-28 13:50:33 Browse：58℃

Compared to gear hobbing, gear hobbing has its own characteristics in terms of machining quality, productivity, and application range

Processing quality of gear hobbing

(1) When the tooth profile accuracy of hobbing is higher than that of hobbing, the number of tangent lines of the travel tooth profile envelope is only related to the number of chip pockets 

on the rolling cutter and the number of basic worm heads. It cannot be increased or decreased by changing the machining conditions

However, during gear hobbing, the number of tangent lines that form the tooth profile envelope is determined by the size of the circumferential feed rate and can be selected. 

In addition, when manufacturing gear cutters, an approximately shaped worm is used to replace the involute basic worm,

There is a form error here. The tooth profile of a gear hobbing cutter is relatively simple, and precise involute tooth profiles can be obtained through high-precision grinding. 

So gear hobbing can achieve high tooth profile accuracy.

(2) The roughness of the tooth surface after gear hobbing is finer than that of gear hobbing because the rolling cutter intermittently cuts

 in the tooth direction during gear hobbing, forming fish scale like ripples, while the gear hobbing cutter continuously cuts along the tooth direction during gear hobbing

So when inserting teeth, the roughness of the tooth surface is relatively fine.

(3) The motion accuracy of gear hobbing is worse than that of gear hobbing because the transmission chain of the gear hobbing machine has an additional tool worm gear pair,

 which means there is an additional transmission error. In addition, one tooth of the hob corresponds to cutting the workpiece

Due to the presence of a tooth slot, the cumulative error of the gear hobbing tool itself will inevitably be reflected on the workpiece. However, 

during gear hobbing, because each tooth slot of the workpiece is machined by the same 2-3 turns of teeth on the rolling cutter, the rolling cutter's

The cumulative error of tooth pitch does not affect the sawing accuracy of the processed gear, so the motion accuracy of hobbing is higher than that of hobbing.

(4) The tooth alignment error of gear hobbing is larger than that of gear hobbing. The tooth alignment error during gear hobbing is mainly determined by the parallelism error between

 the spindle rotation axis of the gear hobbing machine and the worktable rotation axis. Due to the high frequency of reciprocating motion of the gear hobbing tool during operation,

The wear between the spindle and the sleeve is increased, resulting in a larger tooth orientation error for gear hobbing compared to gear hobbing