Study On Oil-jet Lubrication And Cooling Performance Of High Speed Gear

High-speed gears will generate a lot of heat due to friction during transmission.Sufficient lubrication and cooling are required to ensure the safe and reliable operation of the transmission system.This thesis takes meshing spur gear pairs as the research object,establishes thermal analysis,temperature field finite element analysis and flow-heat coupling calculation analysis models.(1)Thermal analysis of spur gears,analysis of the distribution law and size of gear friction heat and convective heat transfer coefficient and related influencing factors,and a calculation program.The results show that with the increase of the input speed and torque,the friction heat flux on the gear surface increases and the increment decreases gradually.As the speed increases,the convective heat transfer coefficients of the gears increase,but the increase gradually decreases.Gear thermal analysis provides boundary conditions for solving the temperature distribution of gears.(2)After getting the thermal boundary conditions,and the transient thermal analysis of the gear temperature field is performed.Heat flux method and heat source term method are used to calculate and compare the temperature field of gear.The results show that the minimum temperature and average temperature calculated by the two methods are basically the same,but the maximum temperature calculated by the heat flux method is slightly higher than that by the heat source term method.With the increase of torque and speed,the maximum temperature of the gear body temperature field shows an upward trend with the increase of torque and speed,but as the torque and speed increase,the temperature rise trend decreases.(3)Use the calculation result of gear friction heat as the boundary condition of the flow field calculation,and the flow and temperature fields of the gear oil injection lubrication were calculated to obtain the oil distribution and temperature field distribution of the gear under different fuel injection velocity,torque and rotational speed.The results show that increasing the injection velocity can improve the lubrication effect and cooling performance,but the improvement of the lubrication effect and cooling performance becomes less and less when it increases to a certain extent.The increase of torque will weaken the lubrication effect,but when the torque increases to a certain extent,the weakening of the lubrication effect becomes smaller and smaller.The maximum gear temperature increases with the increase of torque,and the distribution is close to linear.The change of torque has a great influence on the temperature field of gear.The increase of the speed will make the lubrication effect worse,but as the rotation speed increases,its weakening effect becomes smaller.The maximum temperature of the gear increases with the increase of the speed,and the distribution is nearly linear.