| As a new type of universal coupling,tripod sliding ball universal coupling has the advantages of simple structure,convenient manufacturing,processing,assembly and disassembly,easy maintenance,low friction loss,low cost,and convenient lubrication.In this paper,the sliding ball of the trigeminal rod sliding ball universal coupling is redesigned,the line contact elastohydrodynamic lubrication model is established,the lubricating oil is selected as the lubricant,the main wear parts are numerically analyzed under isothermal conditions,and the effects of surface roughness and other different parameters on the lubrication characteristics are studied.Secondly,the lubricating grease is selected as the lubricant,and the main wear parts are numerically analyzed under isothermal or temperature rise conditions to study the influence of different parameters on the lubrication characteristics.Finally,the influence of spherical small solid particles in grease on the lubrication characteristics is studied.Paper main research content is embodied in the following respects:（1）The sliding ball of tripod sliding ball universal coupling is redesigned to become a new structure.There are multiple rows of parallel annular protrusions on the sliding ball.Based on the simplified geometric model of sliding ball and cylinder slideway,a numerical calculation model of line contact Isothermal EHL considering surface roughness is established.The oil lubrication characteristics of tripod sliding ball universal coupling considering surface roughness are studied by Newton Raphson numerical analysis method,and the random surface roughness is used to replace the actual rough surface to analyze the effects of the amplitude and spacing of surface roughness,initial viscosity,equivalent elastic modulus,equivalent radius,axis angle,load and rotation frequency on the film thickness and pressure of lubricating oil film.（2）Based on the simplified geometric model of sliding ball and cylinder slideway,the mathematical model of line contact isothermal grease lubrication is established.The lubrication characteristics of tripod sliding ball universal coupling are studied by numerical analysis method,and compared with the oil lubrication characteristics under the same parameters.The effects of rotation frequency,equivalent radius,and grease viscosity on the pressure and thickness of lubrication film are analyzed.（3）Because temperature is an important reason to change the characteristics of grease and cause the deformation of parts,based on the simplified geometric model of sliding ball and cylinder slideway,the thermal elastohydrodynamic mathematical model of line contact grease lubrication is established.The lubrication characteristics of tripod sliding ball universal coupling considering temperature rise are studied by numerical analysis method,and compared with the isothermal grease lubrication characteristics under the same parameters.The effects of rotating frequency,equivalent radius and grease viscosity on the distribution of lubricating film pressure,film thickness and temperature rise are considered.（4）Since the solid particles in the grease are also an important reason for the change of lubrication characteristics,the influence of solid particles is considered when studying the lubrication characteristics.Based on the thermal elastohydrodynamic mathematical model of line contact grease lubrication,considering the influence of a single spherical micro solid particle on the lubrication characteristics,the model is established,the Reynolds equation is modified.The lubrication characteristics of tripod sliding ball universal coupling considering temperature rise are studied by numerical analysis method.The effects of solid particle center position,moving speed and radius size on lubricating oil film pressure,film thickness and temperature rise distribution are considered. |
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