Research On Micro Texture And Bearing Properties Of Gear Surface Based On Fractal Theory

As a universal transmission part,the machining accuracy and quality of gear are crucial to the reliability and stability of mechanical transmission.In order to achieve stronger tooth surface lubrication and improve the anti-adhesion and wear ability of gears,configuration design of tooth surface has been widely applied.This paper relies on the National Natural Science Foundation of China "Research on gear surface configuration design and contact bearing characteristics of self-lubricating gear with cross scale",The micro texture design and mechanical properties of tooth surface are studied.Aiming at the field of micro texture design,the diversity and irregularity of texture design are taken as the main research objectives,and the method of tooth surface configuration based on the fractal theory is proposed,and the theoretical model of tooth surface fractal texture is studied.According to the assessment standards of fractal dimension,considered the contact load of gear,normal damping and normal stiffness of fractal dimension,the fractal texture design of tooth surface is realized.According to simulation of MATLAB,when the fractal dimension is 1.5,the tooth surface has the best bearing capacity,when the fractal dimension is about 1.65,the tooth surface has a good damping effect.In addition,the analysis of simulation shows that when the fractal dimension is 1.5,the normal stiffness is reached maximum.Since the fractal texture in this region has good mechanical properties,the fractal texture with fractal dimension of 1.5 or so should be selected for tooth surface design.In order to analyze the relation between fractal dimension and roughness,the 7 sets of machined sample blocks are observed by SEM,it is found that the characteristics of medium and roughed surface can be measured by fractal dimension,and the complexity of the surface contour can be distinguished by fractal dimension even under the same value of surface roughness.In order to test the lubrication effect of fractal texture,the fractal texture and conventional texture were compared and analyzed through CFD simulation,it is found that fractal texture has better effect of hydrodynamic lubrication than conventional texture,and the larger first-order size of fractal texture,the better effect of the hydrodynamic lubrication.Therefore,the optimal lubrication performance of the tooth surface can be achieved by reasonably selecting the first-order size which combines with the actual oil distribution area of the tooth surface.The design of tooth surface configuration is studied from the perspective of fractal,and the mathematical model of fractal graph is applied to design tooth surface profile.A new idea of tooth surface configuration based on fractal dimension is established and the fractal texture design of tooth surface is realized.This paper provides a design scheme for the application of fractal graphics in micro-texture design and also provides a theoretical reference for the lubrication design of other mechanical surfaces.