Internal spur gear is the object of study and build finite element analysis modal.Solid model is built based on PRO/E

and finite element is built based on pro/mechanica.Make use of sensitivity analysis technology of pro/mechanica to study the main structure parameter witch affects internal spur gear stress.The graph of relation between internal spur gear and its structure parameters are obtained.The results indicated that increase the modification coefficient the stress of gear at the pitch line will be increased

and increase module

working pressure angle and addendum coefficient will decrease the stress of gear at the pitch line.