Research On Lubrication And Dynamics Characteristics Of The Hypoid Gear Pair Based On The Micro-dimple Tooth Surface

As a key component for power transmission of rear drive transmission system,the lubrication condition of the hypoid gear pair directly affects the transmission performance and vibration level of the rear axle system of the vehicle.As a kind of effective technical means to improve the lubrication performance of contact surfaces,surface micro-texture has obtained considerable research and application in the fields of mechanical seals,bearings and so on at home and abroad.In this thesis,the hypoid gear pair of automobile main reducer is taken as the research object,and the surface micro-texture is applied to the lubrication performance improvement of the hypoid gear pair to achieve the purpose of anti-friction and vibration reduction.The tooth surface micro-dimple design is taken as the main line of research,and the research on the tooth surface contact parameters,2D tooth surface micro-dimple shape parameters,3D tooth surface micro-dimple arrangement parameters and the dynamic performance of the engagement of the micro-dimpled tooth surfaces are successively carried out,which provide new ideas for new hypoid gear design and provide theoretical support for engineering practice.Firstly,the mathematical model of the engagement of hypoid gear pair is established,and the motion parameters of the meshing tooth surfaces are obtained.Based on the finite element method,the CAE simulation model of the hypoid gear is constructed.Combined with the imprint contact test of the hypoid gear pair,the tooth surface contact characteristics and the specific imprint position of the gear pair are studied.Secondly,the problem of meshing lubrication of hypoid gear is simplified into a 2D plane sliding lubrication model and the tooth surface micro-texture is introduced to improve its lubrication and vibration characteristics.According to the relevant experimental data and boundary layer theory,the type of tooth surface micro-texture is determined as micro-dimple.The shape parameters of 2D micro-dimple are designed and their parametric simulation studies are completed.Further,considering the cavitation effect,the square micro-dimple and trapezoidal micro-dimple with the equivalent lubrication performance and the same value in depth and width are taken as the subsequent research object.The effect of slip speed on the lubrication performance of the two is studied.It is determined that the critical slip velocity of cavitation effect is between 3~5m/s,and the result of optimization of shape parameters of 2D tooth surface micro-dimples is determined as the square micro-dimple with width and depth values of 160?m and 4.5?m respectively.Furthermore,on the basis of the above research,the lubrication performance of single 3D cylindrical micro-dimple and 3D cuboid micro-dimple is compared.Then,the cuboid micro-dimple with the dominant lubrication performance is taken as the further research object.The influences of the micro-dimple spacing and arrangement on the lubrication performance of the 3D micro-dimple array tooth surface are studied under different slip speed conditions.It is determined that the cuboid micro-dimples with length,width and depth of 160?m,160?m and 4.5?m respectively have a better lubrication performance when squarely arranged with a horizontal and vertical spacing value of 200 ?m.Finally,a 3D micro-dimple array with a total number of micro-dimples of 1600 is arranged on the contact impression position of some bevel gear passive convex surfaces.The dynamic simulation software is used to study the influence of the micro-dimpled tooth surfaces on the meshing dynamics of the hypoid gear pair.The results show that the introduction of the tooth surface micro-dimple arrays has less influence on the transmission error and the average meshing force of the gear pair,the former only increases by 0.0008%,and the latter increases by 20.5N with an increase of 0.64%.