Study On Maintenance State Evaluation Methods Of Rocker ARM System Of Shearer

With the rapid development of modern industrial technology,mining equipment has been continuously upgraded in terms of functions and performance,but the complexity of composition of equipment and risk of failure had continued to increase at the same time,and its problems in terms of reliability,maintenance and protection have become increasingly important.As one of the most important equipment in mining,the quality of shearer‘s life cycle must be stressed in addition to meeting its design and manufacturing quality requirements before it is put into use,that is,ensuring equipment has good availability.However,reliability of mining equipment cannot be increased without limits due to limitations on manufacturing level,materials,and expenses.Therefore,availability of equipment will depend more on level of maintainability,and it is necessary to avoid various kinds of problems such as maintenance difficulties and high maintenance costs through good maintenance design.Rocker arm is the site where shearer is most likely to fail.It is of great theoretical and practical significance to study maintainability of rocker arm system of shearer to master rocker maintenance state and implement maintenance task.Based on this,this paper took rocker arm system of shearer as the object of study,and its maintenance state evaluation methods were studied deeply,and main research contents included:(1)Firstly,the structural composition and functional principle of rocker arm system of shearer were introduced.Based on this,functional block diagram of rocker arm system was drawn,and relationship between overall reliability of system and reliability of each component was analyzed,and the reliability analysis model of series parallel was established.Afterwards,preliminary maintenance analysis was performed on rocker system and a corresponding maintenance physical relationship model was established,including maintenance flow diagram and system function hierarchy diagram.Finally,based on FMEA analysis,failure mode and maintenance information database that can realize initial discrimination of failure of rocker arm system of shearer and provide corresponding maintenance strategies was established,which would lay a foundation for maintenance analysis and evaluation of rocker arm system of shearer.(2)A comprehensive evaluation method of maintenance state of rocker arm system based on qualitative index was studied.In combination with layout and structure of rocker arm and actual maintenance situation,maintenance evaluation index system was established,and weight of each evaluation index was determined by TFAHP.Then,rocker arm system of shearer was divided into subsystems,and a two-level fuzzy comprehensive evaluation model for each subsystem was established,and maintenance level of each subsystem was evaluated.Afterwards,weight of each subsystem was determined according to failure rate of each subsystem.Finally,maintainability level of rocker arm system based on qualitative analysis was determined,at the same time,the key subsystems and key indicators affecting maintenance state of rocker arm system were confirmed.(3)A comprehensive evaluation method of maintenance state of rocker arm system based on quantitative data was studied.The maintenance time data was used fully,and then,distribution type of maintenance time data was determined by the method of theoretical distribution fitting,and maintenance degree function and maintenance density function model were determined.Afterwards,point estimation and interval estimation of quantitative index of maintainability of rocker arm system were determined by maximum likelihood estimation,to measure maintenance state of rocker system.Finally,considering low credibility of a single indicator,multiple quantitative indicators were selected for gray cluster evaluation,maintainability level based on quantitative evaluation of rocker arm system was determined.(4)It was obvious that the above analysis process had some problems such as inconvenient handling and poor human-computer interaction in practical application.Therefore,software system for evaluation of maintenance state of rocker arm of shearer based on LABVIEW and MATLAB was developed.The one-button calculation of fault diagnosis,qualitative and quantitative evaluation was realized,and software platform was friendly and easy to operate.At the end of article,the work was summarized and relevant research techniques were prospected.