Sealing Reliability Of Electro Hydraulic Servo Mechanism And Its Test Research

Electric hydraulic servo mechanism is the key component to achieve the control of missileflight attitude, its reliability and the longevity are not only related to the workability of themissile in its specified storage time, but also the huge economical loss caused by the reasonablescraping of product. For this high reliability and long-life products of electric hydraulic servomechanism, it is difficult to obtain failure data by conventional Life-test method.How to assessits reliability and longevity in the condition of feasible time and funding is lack of appropriatetheories and methods. Therefore, how to realize the fast and reliable assess to storage reliabilityof electric hydraulic servo mechanism in short period in order to ensure the missile combat tasknot affected is the problem to research and solve. This paper carrys out the study of the electrichydraulic servo mechanism based on the degradation date of multiple performance parametersby using the testing method of accelerated degradation, then the longevity can be evaluatedreliably by the degradation date obtained from test. This paper’s main research work is asfollows:Firstly, generalize the subject background and significance, summarize the researchprogress of reliability at home and abroad, review the accelerate life test, accelerate degradationtest and statistical analysis method of their test data, analysis the research situation of the electrichydraulic servo mechanism sealing reliability and points out the deficiency, on this basis, thisstudy proposed content and ideas.Secondly,make sure that the failure mode of every parts and components of the electric hydraulic servo mechanism with their influence and harm degree to system, on the base of the research of constitution, working principle and working requirements of the electric hydraulic servo mechanism, through fault tree analysis (FTA) and failure mode, effects and criticality analysis (FMECA) for electric hydraulic servo mechanism. Make a further analysis of the structure and failuretype of the actuator, determine that the aging of NBR O-ring is the main failure reason.Thirdly, regard temperature as and accelerate the factor, analysis electric hydraulic servomechanism’s NBR O-ring used in failure mechanism of storage environment. Combine the changes of micro-reaction and macro-mechanism, establish the degradation path and accelerationequation of NBR seal in the storage environment, combine the probability and statistics theory,establish the complete reliability statistical model of NBR O-ring in the storage environment.Laid a foundation for working out NBR O-ring accelerate degradation test and treating test data.Fourthly, take the temperature stress as the acceleration factor, has formulated NBR O-ringacceleration degeneration test plan, made has based on multiple degradation data of statisticsanalysis method, through constant stress accelerated degradation test obtained two parameter ofperformance degradation data, test data were processed by applying the approximation standardsand least square method, get the reliability of the statistical model parameters, Also through thetest the prediction of storage life of NBR o-ring under special storage conditions was made.Finally, it sums up the research content of entire dissertation, points out in the electrichydraulic servo mechanism acceleration degeneration testing method research needs further tostudy content and this Foundation project next step work direction.