| Compared with traditional gears,the asymmetric gear transmission has a higher comprehensive carrying capacity and can reduce the weight of the transmission system.Asymmetric gears increase the overlap of the transmission,increase the bending strength of the gear,and have better transmission performance and more High mechanical efficiency.This dissertation takes asymmetric helical gears as the research object and studies its oil injection lubrication characteristics,including the establishment of a computational fluid dynamics model for asymmetric helical gears,analysis of factors affecting oil injection lubrication.Analysis and study of the temperature field of the asymmetric helical gear body and the heat transfer coefficient of the tooth surface flow.The main research work of the thesis is as follows:(1)Established a computational fluid dynamics simulation model for asymmetric helical gear oil injection lubrication.The relevant parameters are set in the solution process,and a reasonable distribution of the oil-gas ratio and gas-liquid total pressure of the lubricating oil is obtained by preliminary calculation,which provides a solution for the study of the factors affecting the effect of oil injection lubrication.(2)The process of oil injection lubrication on the engagement side and oil injection lubrication on the engagement side is studied and analyzed,and the distribution of the oil-air ratio and the total gas-liquid pressure of the lubricating oil at the meshing point under the condition of asymmetric helical gear oil injection lubrication are obtained.And the law of change,focusing on the analysis of the influence of fuel injection parameters(lubricant viscosity,gear speed and fuel injection speed)on the oil-gas ratio and gas-liquid total pressure at the meshing point.(3)The combined effect of the coupling of lubricating oil viscosity,gear speed and fuel injection speed under the condition of asymmetric helical gear oil injection lubrication on the changes of oil-gas ratio and gas-liquid total pressure at the meshing point is studied.The change surface diagram of the oil-gas rate and the total gas-liquid pressure at a point can intuitively reflect the matching conditions of the fuel injection parameters that are more beneficial to the gear fuel injection lubrication.(4)The tooth surface contact stress,relative sliding speed,tooth surface friction coefficient and tooth surface friction heat flow are analyzed and solved,and the tooth surface heat flow distribution law considering the lubricant oil is obtained,and the tooth surface,tooth top surface and end surface are analyzed.Face-to-flow heat transfer coefficient and considering the role of lubricating oil provide boundary conditions for solving the temperature field of the gear body.Using ANSYS Workbench steady-state thermal analysis module,the finite element thermal analysis model of a single gear tooth was established and solved,and the influence of the tooth surface and end surface flow heat transfer coefficient on the temperature field of the tooth surface body was obtained.(5)The simulation calculation of the average instantaneous temperature of the meshing tooth surface of the asymmetric helical gear provides boundary conditions for the simulation analysis of oil injection lubrication.Through the calculation of fluid dynamics simulation of oil injection lubrication,the distribution of tooth surface flow heat transfer coefficient and the average convection heat transfer coefficient of tooth surface are obtained.The average convection heat transfer coefficient of tooth surface can reflect the cooling effect of lubricating oil on tooth surface.Finally,the influence of different lubricating oil viscosity and fuel injection speed on the average convective heat transfer coefficient of tooth surface is studied. |
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