Considering The Influences Of Roughness To The Gear Contact Strength Model Research

Gear is one of the important mechanic parts,and its normal work has a important influence on the performance and reliability of the mechanical system.T he development of modern industry is also put forward higher requirements for the application of gear,accurate calculation of contact strength must be conducted to e nsure its contact stress within the safety allowable value,so an accurate loading ca pacity calculation method appears particularly critical.Based on the fractal theory,fractal contact model of gear with different roug hness is established by regarding the contact of meshing gear as the contact betwe en multiple curvature and variously sized asperities, and comprehensive considerin g the elastic-plastic deformation on contact of asperity.On macro perspective, simp lifying the contact between gears to the contact between the two cylinders,accordi ng to the relevant conclusions on Hertz elastic contact theory,the contact areas are obtained under certain condition between two gears.On micro perspective,consider ing the contact areas of two gears as contact of rough surfaces, and according to fr actal theory,the deformation of multiple asperities with the rough surfaces is analy zed,which accords the model with the practice contact of gears.1) Introduces the definition and characteristics of fractal theory,fractal parameter calculation method and its theoretical development course.Analyzed the advantage of the fractal parameters to the statistical parameters in characterization of rough surface,and analyzed gear fractal characteristics of gear grinding processing.Establish a function of a grinding gear surface roughness Ra and fractal dimension D value.2) Based on the fractal theory,modify the M-B model by building a coefficient,Get the contact model by consider the fractal characteristics of two rough surface, and the influence law of the three main parameters of the model was analyzed and compared with experimental data,The rationality of the correction model was verified.Simulation results show that the model is more consistent contact with the actual situation,it can provide accurate analysis model for friction and wear prediction, wear particle analysis and different roughness surface contact analysis.3) By constructing the gear contact coefficient and get the gear fractal contact model considering the effect of roughness,Then take further analysis to the model,To study the changes of optimal value of fractal dimension,gear contact elastic and plastic deformation and take comparative analysis to different gear tooth surface hardness, We obtained the law with some good practical value.4)Will the same set of gears respectively using Hertz contact theory calculation method, the finite element analysis method, the gear fractal contact model for contact strength analysis,and compared with experimental data to get result of error analysis to verify the accuracy of the model.It can get precise results analysis of the gear contact strength and can be a good simulation of gear contact situation actually.