Temperature Rise Analysis And Test Research Of Mechanical Transmission

The Transmission will generate heat due to friction and other reasons at run time.If the heat can not be dissipated in time,it will make the transmission oil temperature exceed its maximum use temperature and cause the transmission parts damaged because of the the failure of the lubricating oil and the high temperature.That is very dangerous for a moving car.So the research on the transmission oil temperature rise is very important for the safety of the vehicle.Domestic transmission oil temperature rise test bench are mostly for heavy duty truck at present.But for the mini-car,the test persons usually use the real vehicle test to detect the maximum transmission oil temperature.So in order to detect the maximum operating temperature of mini bus transmission,This thesis designs an electrically closed mechanical transmission test bench with DC-bus to feed-back energy based on Visual Studio 2005(VS2005).Due to the temperature rise test data is only the oil temperature value of the sensor,So this thesis makes a steady-state analysis of the transmission to get the steady-state temperature distribution of the transmission and its components combining with the simulation software ANSYS Workbench 15.0.The main research works include:1)By using the basic formulas of heat transfer and the empirical formulas which are associated with the heat analysis of transmission to analyze the mechanism of transmission oil temperature rise theoretically.Estimating the heat production of different heat sources and using the SIMULINK component of MATLAB to model and simulate the heat production of the heat sources.Then,the thesis gets the relationship between power loss of different heat sources and time during testing,estimating the final steady-state temperature value of lubricating oil theoretically at last.2)Stating the advantages of the electrically closed mechanical transmission test bench with DC-bus to feed-back energy by comparing it with those traditional test benches,Also making a detailed introduction to the basic structure,the latest research result of electrically closed test bench and the methods of test bench which including testing,communication and data acquisition methods.At the same time,the thesis introduces the use of the host and lower computer in the test bench.3)Modeling the whole transmission by using the three dimensional drawing tool UG8.0 and importing the model into the simulation software ANSYS Workbench 15.0 to do transient thermal analysis,then the thesis gets the final steady-state temperature value of lubricating oil by simulating and also the value is analyzed.4)Comparison and analysis of the theoretical calculation,the simulation and the test data.The thesis lists the problems appearing in the test process with its solving methods and proposes suggestions for subsequent transmission test bench development at last.This thesis uses a calculation method to estimate steady lubrication oil temperature and builds the temperature rise simulation model of transmission.According to the comparative analysis of test data,theoretical calculation and simulation result,the accuracy of the theoretical estimation formula and simulation analysis method is verified.The theoretical estimation result provides theoretical basis to the test result.The simulating result makes up for the limitation of the test result which only has the data of the oil temperature sensor.After comprehensive debugging,the test results show that the transmission lubrication oil temperature in 5 gear is the highest and maintain stability at 142 ?which is lower than the maximum operating temperature of transmission oil more than 0.5 hours longer in high speed without external heat dissipation and the transmission is always in normal operation state during the whole testing process.The test result provides a guarantee for the normal operation of the transmission in the absence of external heat dissipation.