Reliability Analysis Of Hydraulic Torque Converter Based On FMECA And FTA

Hydraulic torque converter is widely used because of its excellent automatic adaptability,stepless speed change,good low-speed stability,vibration reduction and no mechanical wear and tear.With the development of science and technology,the requirements for safety,efficiency and torque of hydraulic torque converter are gradually improved.The hydraulic torque converter can be maintained properly to decrease the failure rate and improve the reliability effectively through the reliability analysis.Analyzing the reliability of the hydraulic torque converter and provide a solution to certain key failure modes in this paper.A monitoring program is designed for these failure modes with the calculation of the key parts reliability.The main research contents are as follows:Based on the fault data obtained from the investigation,the hydraulic torque converter is divided into four subsystems according to their different functions by using fault mode.impact and hazard analysis(FMECA).Listing the failure modes of each subsystem,analyze the causes of the failure and then provide the compensation measures.By using the comprehensive scoring method,the hazard degree of each failure mode is calculated and measured by hazard value and severity grade to determine whether they are key failure modes or not.Fault tree analysis(FTA)is used to analyze the critical fault modes and obtain the minimum cut set and bottom event importance of each critical fault mode.Through the analysis of each importance value,solutions are proposed for the higher importance bottom events,which can provide reference for the design and maintenance of hydraulic torque converter.The key failure modes are divided into high-severity fault modes and high frequency occurrence fault modes.Based on the stress-strength interference theory,the reliability of parts with high-severity fault modes is calculated to verify whether the reliability of the parts meets the requirements or not.Based on LabVIEW,several fault modes with high frequency of occurrence can be monitored in real time.Measures can be taken instantly to avoid the fuurther impact of the fault mode on the system,so as to improve the reliability of the hydraulic torque converter system.