Failure Mode Identification And Mechanism Analysis Of Automotive Hub Bearing Unit

Hub bearing unit(HBU)is a type of critical automobile parts,whose quality influences the comfort and safety of automotive during driving.Mode identification and mechanism analysis of HBU failures are important for its excellent performance and reliability.The study focus on failure analysis of HBU,implement life predication,non-destructive NVH test and destructive physical and chemical inspections in turn.An estimation method of automotive HBU failure rate in application was proposed based on software simulation,rig test,and Bayesian parameter estimation theory.SKF SimPro Export software calculation for theoretical combination life,time terminated testing of small sample size for practical life,and Bayesian parameter estimation method for failure rate prediction base on above data were combined to analyze the engineering application of HBU in car corner system under alternating load spectrum.Based on NVH condition monitoring method,fingerprint method(FPM)and comb filter marking method(CFM)were proposed and verified individually for vibration signal analysis of discrete and continuous defects on HBU working contact surface(WCS).The raw spectrum would be envelope demodulated and compared with fault characteristic frequencies of bearing components so that discrete defects could be diagnosed.The raw spectrum would be comb filtered by various waviness orders characteristic of bearing components,and relevant vibration modes would be identified so that the most affected waviness orders could be diagnosed as continuous defects.The method has been verified by multiple instances.Several approaches of HBU failure mode identification were systemically summarized in terms of physical and chemical features base on typical instances.The procedure of inspections was explored so that the accuracy rate of failure analysis could be improved and the requirement on professional experience ofengineers in the field could be reduced.This method thus provides a basis for the standard procedure of HBU failure analysis.