Introduce the principle and possibility of use isochronous system of spline processing beuel gear,stress on whew the feeding is certained,change gear calculation method form isochronous system compensate and error checking calculation for machining workpiece.

Result is that change gear can't be chosen or processing is not normally.

This paper analyses the calculating characteristic of change gear sets of hobbing machine Y3150E.

Selective procedure of change gears of general hobbing machine;

The design of selective procedure of change gears used for additional movement of hobbing machine;

The software based on Visual Basic used in the calculation and selection of change gears in gear hobbing process is developed in this paper.

This paper introduces a simple homemade gear change matching table for milling spiral groove.

Aim for the problem that producing gears exist precision low and error big in practical produce,passed to technically regenerate to differential hanging gears of primeval equipment(Y320 roll-gear machinery),improved some big module-small spiral angle gears of producing quantity,attained to user requirement,and received the satisfactory economic performance.

In this paper,computer technology is applied to solve the problem that exist in selecting the differential hanging gears,such as database generation、hanging gears finding and big error of traditional calculation method,and to improve the precision and speed of finding differential hanging gears,and to satisfy the needs of actual processing.