Research On Reliability And Oil Contamination Control Technology Of Coal Equipment Hydraulic System

Hydraulic system is widely used in the coal machine equipment,and becomes an important part of the equipment.Its reliability level directly determines the performance of the whole machine,and then affects the efficiency of coal mining and the economic benefits of enterprises.Therefore,the reliability analysis of hydraulic system for coal machine equipment is very important to the safety and stability of machine operation,because we can find the weakness of system through this measure,and put forward the improvement and prevention methods to prevent the occurrence of failures.Firstly,this paper introduces the reliability characteristics of the hydraulic system,which provides a theoretical basis for the reliability analysis of the hydraulic system.Three kinds of coal mining machinery equipment hydraulic system are researched,including the Boom-type roadheader hydraulic system、support hydraulic system and shearer lifting hydraulic system.According to the reliability theory of hydraulic system,the reliability block diagram and reliability mathematical model of hydraulic system is established.Then,the reliability of the hydraulic system of the coal machine is analyzed by reliability analysis technique.The Boom-type roadheader hydraulic system is analyzed by the FMECA method.It can find out the important parts and weak links of the system,which can provide important information for the evaluation and improvement of the system.According to the statistics of the support hydraulic system fault and the fault tree analysis(FTA)theory,the fault tree of the hydraulic system is established.The logical relationship between the fault modes is clearer,which is easy to find the most basic events.The aim is to improve the reliability of the hydraulic system.It is found that the oil contamination is the weak link according to the reliability analysis of the coal machine hydraulic system,and seventy-five percent to eighty percent faults of the hydraulic system is caused by the oil contamination.It is necessary to study the oil contamination control technology to improve the reliability of hydraulic system.This paper describes the source,type and harm of oil contamination.Four basic filtering systems are analyzed and studied,and the system schematic diagram and the mathematical equation are established.The contamination control mathematical model is established by analyzing the hydraulic system of the coal machine.The influence of related factors in the equation is studied.It is found that the speed of oil purification rate becomes faster when the volume of the oil tank is smaller,which is beneficial to the oil contamination control.Then,the theory of small oil tank is put forward,and the system schematic diagram is established.It provides a theoretical basis for the research of oil contamination control technology.Filter performance testing is the key to the implementation of hydraulic system oil pollution control.Take the support hydraulic system filter as an example,the effect of filtration ratio on the system is studied,and the influence of different test dusts on the results is tested by multi-pass test method.It provides a reference for the control of oil contamination and the rational evaluation of filters.At the same time,it is also helpful to improve the reliability of coal machine hydraulic system.