Research On Reliability Engineering Platform For Hydraulic System Of Excavator

In recent years,domestic excavators have begun to gradually replace foreign brands in the market.For the medium and large excavators,foreign excavators advanced levels is still large,and the main reason is poor reliability.Due to the characteristics of large investment cost and long payback period of reliability research,the reliability research has not formed an effective closed-loop process,and the practical work of the excavator lacks an effective application of reliability theory.Therefore,by establishing the reliability engineering platform of the excavator and incorporating the reliability theory into the actual work of the excavator,it has certain practical significance for improving the reliability level of the excavator.The main research contents include:Firstly,the definition of reliability of the excavator and the commonly used reliability features are described.Based on the current status of the excavator industry,a demand analysis is performed on the reliability engineering platform of the excavator.The main business process of the platform is designed.The platform architecture,functional structure and key technologies are determined.Briefly analyze the composition structure and working principle of the more common backhoe crawler hydraulic excavator.Based on the actual situation of the excavator,it is establishd the reliability block diagram of the hydraulic system.At the same time,according to the actual working conditions of the excavator,the failure rate is corrected.The mean time between failures(MTBF)of the hydraulic system is calculated,and the reliability curve is drawn.The Monte Carlo simulation method is designed to improve the applicability of the model.In order to improve the efficiency of fault diagnosis,the excavator fault level is divided according to the fault phenomenon.Using FMECA,analyze the arm circuit in the hydraulic system of the excavator,complete the FMECA table,and find out the more fatal failure modes and components.Based on the connection between FMECA and FTA,the fault phenomenon of "No stick action" is selected as the top event to establish a fault tree model,and the corresponding causes are found to quantify the importance and other indicators.Aiming at the blindness when using fault tree for fault search,triangular fuzzy mathematics was introducedto establish a decision matrix.The combination of analytic hierarchy process and entropy weight method is used for combined weighting.The TOPSIS algorithm is used to formulate the fault search strategy,which optimizes the efficiency of fault handling.Based on the overall design and reliability research,the logical structure design and base table design of the database required by the platform are performed.Visual Studio 2012 and SQL Server 2012 were used as development tools to complete the preliminary development of the reliability engineering platform of the excavator.Reliability research was integrated into the platform functions,and the corresponding functions of the platform were initially realized.