Research On The Influence Of Micro-geometry Profile On Meshing Vibration And Lubrication Characteristics

Gear system vibration problem is the key content of the gear system dynamics problem.How to improve the vibration performance of the gear system as far as possible has always been the focus and research focus of scholars in various countries.There are many factors that affect the vibration characteristics of gear systems,including time-varying meshing stiffness,transmission error,backlash,and other complex nonlinear factors.In this paper,from the perspective of the surface micro-geometric profile,the influence of the micro-geometric profile of the tooth surface on the gear meshing vibration characteristics and lubrication performance is discussed.Firstly,the influence of the micro-geometric profile of tooth surface on the gear meshing vibration characteristics was analyzed.In the process,two different types of surfaces were obtained by grinding and electro-chemical finishing.Two were measured using a Taylor Hobson stylus measuring instrument.The micro-geometric profiles of the same section position on the surface of the type were calculated and the power spectral density function method was used to calculate the fractal dimension and the characteristic scale of the two types of surface micro-geometric profiles.Based on the fractal geometry theory and Herz formula,the approximate fractal mathematical model of normal contact damping based on the micro-geometric profile of the real tooth surface was established.Based on this,the micro-geometric profile of the tooth surface obtained by grinding and electrochemical finishing was compared.Fractal parameters were analyzed,and the effects of machining methods on the normal contact damping characteristics of the tooth surfaces were analyzed.The influence of the normal contact damping on the gear meshing vibration characteristics was further studied.The results show that the micro geometry of the tooth surface affects the meshing vibration of the gear;the machining method affects the rate of change of the normal contact damping of the tooth surface;compared with the grinding process,the normal contact damping of the tooth surface with electrochemical finishing is greater.It can reduce gear meshing vibration and help improve the stability of vibration.Next,the effect of the surface microscopic geometrical profile on the stiffness and stability of the lubricating film was investigated.In the process,the surface of the journal with the same diameter was treated with electrochemical finishing and grinding,respectively,and measured with a Taylor Hobson measuring instrument.The geometrical profile of the surface of the two types of journals is analyzed by the fractal geometry theory,and the fractal features of the surface microscopic geometrical profile are analyzed.The thickness of the dynamic pressure lubricant film formed between the journal and the bearing shell is measured using a sliding bearing-rotor experimental platform;An approximate mathematical relationship between the thickness and stiffness of the real surface lubricant film was established,and the influence of the surface microscopic geometrical profile with different fractal features on the dynamic pressure effect of the lubricant film was simulated and analyzed with ANSYS FLUNT in order to study the ability of the oil film to resist deformation under the same load conditions.The results show that the surface geometry of the journal surface after electro-chemical finishing is smaller than the surface area of the journal on the surface of the grinding micro-geometry,and the formed oil film thickness is greater and the stability is better.The stability of the oil film thickness directly affects the stability of the oil film stiffness;in addition,the simulation analysis based on ANSYS FLUNT shows that reducing the characteristic scale of the surface microscopic geometric profile enhances the dynamic pressure effect of the lubricant film and increases the bearing capacity of the oil film.The ability of the lubricating film to resist deformation under the same conditions is improved,and the oil film rigidity is increased.