The Experiment Research And Optimization For Transmission Efficiency Of Constant Velocity Driving Shaft On FF Car

With increasing development of economy,the amount of coaches increases rapidly.As a result of the supply shortage of energy resource,the environment pollution,reducing the fuel consumption,energy-saving and environmental protection,promoting fuel economy have become the most important task of the automobile industry.As the key part of precursor and four-wheel vehicle,constant velocity drive-shaft is very important to the safety and comfortableness.Taking the certain front-engine front-drive MPV as the research object,This paper has carried out the plan of improving the transmission efficiency using bench test and vehicle optimization thus improving the fuel economy.The paper mainly finished works as follow:1)The key design parameters which influence the transmission efficiency of drive shaft including the surface roughness of the ball cage constant velocity joint and the housing spout,the number of the constant velocity of ball basket universal joint,the angle of universal joint has been analyzed.The function request of constant velocity joint for grease medium has been introduced,and the influence of the rheological character,the grease thickness on lubrication has been analyzed as well as the influence of the increase of oil.The influence of the key design parameters to transmission efficiency has been pointed out providing the theoretical guidance for making the scheme of improving the transmission efficiency.2)The design principle has been analyzed.The test bench design of constant velocity drive shaft has been finished including the design of electrical machine,torque sensor,magnetic power brake function and the the software design based on LabVIEW realizing the function of exporting torque and rotate speed of the constant velocity drive shaft.3)Using simple variable method,the transmission efficiency of many exemplars with different design parameters have been tested through the bench test.And the working condition of bench test has been designed based on NEDC circulated working condition.The tests have all been finished,exporting the data of all kinds of working condition in order to provide a lot of test data base for making the optimization plan.4)Based on consolidating and analyzing the data,the isokinetic of constant velocity drive shaft has been validated.Comparing the difference between all the transmission efficiency of the drive shaft,it comes to the conclusion that promoting the manufacturing precision,increasing the number of steel balls of joint,decreasing the angle of joint,improving the environment of grease can improve the transmission efficiency.And the angle and the variety of grease have more greater influence on the efficiency.5)Through studying the degree of the influence the factors have on the transmission efficiency,the angle and the grease have a great influence on the transmission efficiency.The primary plan has been made by analyzing the test results.6)The exemplar of constant velocity drive shaft has been made on the base of test data.The vehicle fuel consumption test and coasting test in cold and hot state which validate the feasibility of the plan have been conducted.The results of the vehicle test tell that the optimization plan can increase the coasting distance of vehicle,decreasing d the fuel consumption efficiently.