Study On The Influence Of Solid Particles On Non-steady-state Thermal El Astohydrodynamic Lubrication Of Spur Gears Running-in

The gears lubricating oil is always vulnerable to debris under harsh conditions. The debris may directly cause degradation of lubricating oil lubrication properties, and even seriously cause teeth abrasive wear which can lead to teeth surface contact failure. This paper comparatively systematically researched effects of solid particles shape, speed, position, state of motion and fluctuating load on non-steady-state thermal elastohydrodynamic lubrication of spur gears running-in. The influences of particles flow on non-steady-state thermal elastohydrodynamic lubrication of spur gears running-in were comprehensively investigated considering effects of particles flow of different types on lubricating oil rheological behavior.Firstly, the elastohydrodynamic lubrication mathematical model of spur gears running-in was established. The solid particle position was close to contact inlet zone, Reynolds equation was deduced taking solid particle effect into account. The non-steady-state thermal elastohydrodynamic lubrication of spur gears running-in was investigated considering time-variant effect and thermal effect. Influences of solid particle shape, size and speed on film pressure, film thickness and film temperature were analyzed.Secondly, elastohydrodynamic lubrication mathematical model containing solid particles was set up considering solid particles and teeth surface roughness. The Reynolds equation in contact region was revised. The elastohydrodynamic lubrication analysis of spur gears running-in was obtained reckoning in continuous wave roughness, effects of debris and roughness on film pressure, film thickness and temperature were investigated.Thirdly, the hard and soft particles elastohydrodynamic lubrication models were established. Based on assumption of hard and soft particles characteristics influence of two types of solid particles on thermal elastohydrodynamic lubrication of spur gears running-in was studied taken solid particles, time-variant effect and thermal effect into consideration. Effects of hard and soft particles on film pressure, film thickness and temperature were analyzed.Fourthly, according to measured actual surface topography a function of surface topography was fitted. Teeth simplified load spectrum in running-in process was depicted considering fluctuating load effect. The micro thermal elastohydrodynamic lubrication of spur gears running-in was investigated taken surface roughness, time-variant effect and thermal effect into account. Effects of Load fluctuation frequency, load fluctuation amplitude and fitting roughness amplitude on film pressure, film thickness and temperature were analyzed.Then, the elastohydrodynamic lubrication model of contact region containing debris from the perspective of solid-liquid coupling was set up. Reynolds equation of region where solid particles settle was deduced taking solid particle effect into account. Effects of debris motion position change and spin on film pressure, film thickness and temperature were discussed reckoning in drag force lubricating oil forces on solid particles, changes of solid particles speed during debris motion, solid particle spin and thermal effect. In the end, numerical results were verified.Finally, particle flow lubrication mathematical model was established. The thermal elastohydrodynamic lubrication of spur gears running-in was studied taken influences of particle flow on lubricating oil rheological viscosity and density, time-variant effect and thermal effect into consideration. Effects of different mass fraction of MOS2 on film pressure, film thickness and temperature were analyzed. Effects of 5% synthetic diamond, 45 steel, graphite and MOS2 on film pressure, film thickness and temperature were compared. Moreover, the numerical results were comparatively validated.