Research On Contact Characteristics Of Hypoid Gear Under Assembly Error And Support Deformation

Hypoid gear transmission is widely applied in the automobile rear axle main reducer,with the advantages of strong bearing capacity,stable transmission.More and more high vibration and noise standard has been put forwarded in the car industry,which gives higher request for hypoid gears transmission performance.Hypoid gear pair installation accuracy is very high.Tolerance and wear of shaft,bearing and case all will affect the gear axis position accuracy,so it is necessary to research the hypoid gear installation error sensitivity,optimize predefined parameters and adjust gear cutting parameter during gear geometry design,to reduce the hypoid gear pair installation error sensitivity.In practice,for a designed hypoid gear,through computer simulation,the size and location of contact area are reasonable,and the rolling test also shows good,but large noise and unreasonable contact region may appear according to experimental results on a car.The main reason is that assembly errors exist and the design of hypoid gear geometry has not taken the elastic deformation effect of supporting parts on the change of the axle position into consideration,thus further contact research on hypoid gear system model including support parts to improve its contact performance is of great significance.The main content of the paper is as follows:(1)According to hypoid gear cutting theory,cutting parameters of Formate and generated gear with intermittent indexing method are derived.Based on local synthesis method,by solving nonlinear equations,generated pinion cutting parameters is obtained.This method is not only suitable for line blade profile and circular blade profile,can also be applied to parabolic blade profile and other forms of blade profile.Finally tooth surface cloud data is processed using reverse engineering method,and gear pair geometry model can be used for tooth contact analysis.(2)Tooth contact analysis of gear pair is conducted with theoretic installation to validate the correctness of the model.Error sensitivity of hypoid gear within a certain range installation error is studied with single objective variable.And the installation error sensitivity is used as objective function for optimization of predefined parameters and adjustment of gear cutting parameters,which provide guidance for active design of hypoid gears and adjustment of pinion cutting parameter.(3)Establish the hypoid gear system geometry model including shafts,bearings and box case.Stiffness matrices of bearings are solved and equivalent analysis model of bearings is established.FEA method is used to calculate the contact region and contact pressure of hypoid gear under different contact points and different loads.The amounts of equivalent misalignment and contact point path caused by support deformation are also got,which is the foundation of hypoid gear geometry active design and axle position error compensation.