Considering pitch deviation

profile deviation and helix deviation

the loaded tooth contact model of a helical gear pair is built.A method to calculate the mesh stiffness with gear errors is proposed.The variation law of mesh stiffness and the total length of contact line are calculated when different loads are applied on gears with different precision grades.The calculation results show that the fluctuating state of mesh stiffness is approximately identical with the actual total length of contact line.In a certain precision grade

the mean value of mesh stiffness increases gradually with the increase of mesh force and finally approaches the value of ideal gears.The tooth errors of gear with higher precision will decrease

the mesh stiffness will increase under the same mesh force is applied.