Study On The Impact Of Hub Bearing On Resistance Of Automobile Transmission System And Its Optimization

In the context of the shortage of petroleum resources and the increasingly serious environmental pollution,in order to meet the fuel consumption regulations,a car company urgently needs to conduct resistance optimization research on a certain front-drive MPV with high fuel consumption.This paper uses the combination of theoretical analysis and experimental research to explore the resistance level and distribution law of the target vehicle transmission system,and to clarify the influence weight and optimization space of the hub bearing,the key transmission component,on the transmission system resistance characteristics.The factors affecting the friction torque of the hub bearing are analyzed,and the influence law of various factors on the friction torque is explored through experiments.An optimization scheme is formulated.The optimized samples were loaded and the vehicle resistance and fuel consumption tests were carried out to verify the effectiveness of the optimization measures.The research work and results of this paper are as follows:(1)The energy loss of the drive train during the vehicle power transmission process is analyzed.The test method of step-by-step disassembly is used to test the resistance distribution of drive train of the target vehicle and the benchmark vehicle.The test results show that the average resistance of the vehicle's neutral gear is higher than the two pairs of standard vehicles 14 N and 33.4N.The resistance of the hub bearing + tire part of the drive train accounts for the largest proportion of the total transmission resistance.Compared with the benchmark vehicle,there is a large optimization and improvement space for the target wheel hub bearing resistance performance.(2)The friction torque of the hub bearing unit is analyzed to determine the relevant factors affecting the friction torque.Studies have shown that the seals and grease components of hub bearings have an important influence on their frictional moments.The seal type and structural parameters are optimized,and the optimized seal can reduce the frictional torque of the hub bearing by 12%.The grease formulation was optimized and tested to show that the resulting test grease can reduce the frictional torque of the hub bearing by 9.9%.(3)The optimal working clearance of the hub bearing is studied,and theinfluence of the negative clearance on the bearing friction torque and fatigue life is analyzed.The friction torque test shows that the smaller the absolute value of the negative clearance,the smaller the frictional torque of the bearing.The friction torque can be reduced by up to 11% within the tolerances required by the bearing.The absolute value of the negative clearance is reduced and controlled between 0.01 and0.02 mm.The fatigue life test proves that this range of the hub bearing can meet the fatigue and reliability requirements.(4)The optimization plan for the hub bearing is formulated and the prototype is prototyped.The original wheel bearing and the optimized sample were loaded successively to carry out the vehicle resistance and the fuel economy test of the whole vehicle.The test results show that the optimized wheel bearing can greatly reduce the resistance torque of the whole vehicle transmission system,in which the left front wheel resistance torque is reduced by 6.35%~19.28%,and the right front wheel resistance torque is reduced by 18.41%~21.22%.At the same time,the vehicle fuel consumption is reduced.80 mL / 100 km,the percentage reduction is 1.1%.