| Transmission system of mechanical equipment plays an irreplaceable role in modern production and life,and its failure often leads to serious accidents and property losses.In order to ensure the safe and reliable operation of mechanical equipment,the condition monitoring and fault diagnosis of mechanical equipment is the academic frontier and research hotspot in this field,and also the key research direction of science and technology in China.At present,the vibration energy transfer and dissipation behavior of mechanical interface are studied only considering the surface morphology characteristics.However,the influence of the "regular" processed texture and the "random" component of the texture surface microconvex on the interface vibration is ignored,which will affect the accuracy of service performance monitoring and prediction of mechanical equipment,restrict the reliability of state monitoring and fault diagnosis of mechanical equipment.Thus,it is a key scientific problem to be solved urgently.This paper focuses on the problem of mechanical contact interface characterization and interface dynamic behavior.It starts with the typical surface texture and topography data and statistical characteristics of turning,milling and grinding.Then the analytical function of "regular" processed texture in surface topography is constructed.In view of the interface contact stiffness calculation problem,based on the new texture characterization of surface topography model and elastic matrix "layered cut chip" new method,a texture interface contact stiffness model is constructed considering the interface "regularity" processing texture and micro convex body "random" texture surface morphology.Aiming at the internal excitation mechanism of textured interface in mechanical system,a 6-DOF(Degree of Freedom)dynamic model of machined texture-oil film coupling gear meshing interface is established.Aiming at the problem of vibration transfer of gear transmission system under the influence of multi-interface surface topography,a multi-interface vibration mechanical model of gear transmission system is established.The influence mechanism of different surface texture topography and roughness on the vibration transfer and energy dissipation characteristics of the system is studied.The main research contents are as follows:(1)In view of the lack of characterization methods for "regular" processing texture and "random" microconvex body of contact interfac,the surface topography of workpiece under different machining methods such as milling,grinding and turning are observed by means of microscopic experiment.The statistical parameters such as height and density distribution of sampled contour in parallel and vertical directions are extracted.A new characterization method is proposed considering the evolution of machining texture.The micro-morphology is reconstructed by texture surface optimization algorithm.The correlation between simulation morphology and actual machining morphology is analyzed,as well as the influence rule of fractal roughness and machining texture contribution on morphology characteristics,which lays a foundation for the calculation of texture interface contact stiffness and the study of interface behavior characteristics of mechanical system.(2)For the nonlinear contact stiffness in case of different texture surface morphology interface,a new calculation method of ―layered slice‖ substrate is proposed.A simulation calculation model of texture surface topography is established considering the combination of ―regularity‖ processed texture and ―stochastic‖ microconvex.The effects of interface texture morphology type,surface roughness and elastic substrate thickness on texture interface contact stiffness are analyzed.The interface contact stiffness test rig is established,and the deformation of texture test sample is measured by coaxial laser displacement sensor.The effectiveness of the proposed method is validated by the simulation results of the interface contact stiffness of texture topography,and which provides theoretical basis for the calculation of dynamic characteristics of the texture topography interface.(3)Traditional models only consider the gear mesh interface roughness for gear transmission system in incentive and ignore the influence of different processing gear mesh interface texture of incentive problems in gear transmission system.Thus a calculation method of friction excitation on meshing texture interface is proposed based on the new characterization model of surface topography in Chapter 2 and combined with elastohydrodynamic lubrication theory.Combined with time-varying meshing stiffness and static transfer error,a new 6-DOF dynamic model for meshing interface of machined texture-oil film coupling gear is established using lumped parameter method.Based on the proposed models,the influence of meshing texture interface on the internal excitation and dynamic characteristics of gear transmission system under lubrication condition is studied,which can provide a theoretical basis for the reliable analysis of the effect of meshing interface texture on the internal excitation and dynamic characteristics of the gear transmission system,and also can provide a new idea to reduce the internal excitation of gear transmission system by controlling the interface texture.(4)Aiming at the problem of vibration transmission under the influence of multiinterface morphology of gear box,a multi-interface vibration transfer dynamics model of gearbox is established.The influence of surface topography types(smooth,"random" micro-convex,turning,milling,grinding)and roughness(Ra1.6,Ra3.2,Ra6.3,Ra12.5)on vibration transmission ratio and vibration transmission energy dissipation of the system is studied.The characteristics of multi-interface vibration transmission of gear box considering surface topography are proved,which provides a new method and means for vibration control and early fault diagnosis of gear box. |
