| Coal mining machine is the main equipment in the modern coal mine production,is the essential equipment in the coal mine "three machine",plays an irreplaceable role in the coal mine production.Because the coal mine underground environment is bad,the working condition is complex,the hydraulic brake system of the coal mining machine will affect the life safety of the coal miners,the safety of the coal mining machine itself and the reliability of the operation.At present,there are few researches on the hydraulic brake system of coal winning machine,most of which are mostly theoretical research and lack of in-depth research.The hydraulic braking system of MG750/1940-WD shearer taking heavy coal machine group limited production as the research object,aiming at the phenomenon of coal mining machine in working face with large inclination when braking slipping,analyzed on stress in the face of large inclination of the shearer work force analyzed and calculated through analysis the safety coefficient of braking of the shearer,put forward the indicators evaluation of shearer’s braking performance,comprehensive analysis of the reasons for the decline is affecting the shearer brake response time.In order to analyze the effect of braking response time on the braking performance of coal mining machine,the factors which may affect the braking response time are analyzed one by one.The concrete method is: the coal mining machine brake system is simplified,and the mathematical model of the simplified model is established.On this basis,the simulation software is used to simulate the various factors that affect the braking response time.The specific method is: according to the braking system of the mathematical model,the simulation analysis software to establish the simulation model of key components and the brake braking system,in order to ensure the accuracy of the simulation results,set the corresponding parameters for each element,the flow area and the hydraulic pipe length on the response time of the braking effect of brake spring stiffness,brake spring preload,the oil content of air,hydraulic pipe diameter,solenoid valve.The simulation shows that the pipeline connection between the brake and the brake oil tank will affect the response time,the diameter of the pipe pipe road more long braking response time is longer,but the diameter of the pipe should not be too small,less than 8mm when the resistance is too large,resulting in the braking time;brake spring stiffness will not affect the brake response time,and the role of the brake spring preload;oil in the air content of more than 0.5% will also affect the brake response time;electromagnetic valve cross-sectional area smaller braking response time.Therefore,it is necessary to design a reasonable length and diameter of the pipeline,select the appropriate solenoid directional valve and avoid excessive mixing of oil into the air,so as to achieve the purpose of improving the braking response time,so as to improve the braking performance. |
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