| Short wall shearer is one of the most important equipment to fully-mechanized coal mining face,the dynamic performance of the height-adjusting system plays a vital role in the security and reliability of the whole machine,and has the crucial significance to improve the coal production,production efficiency and extend the life of the equipment.Counterbalance combination valve is a key element in height-adjusting system,it plays an important role during rise,fall and lock of the rocking arm.As a result,there are great engineering application value and theoretical significance to carry on the study of the counterbalance combination value.This dissertation analyses the typical working conditions of short wall shearer and the mechanism of shaking generated during the drop of the rocking arm at first,expounds the design solutions and structure of the new counterbalance combination valve.Secondly using the knowledge of fluid mechanics,after theoretical analysis on the counterbalance combination valve and its balance loop system,established the mathematical model of hydraulic cylinder with the external load and mathematical model of valve control cylinder system;Using AMESim to establish the counterbalance combination valve and its balance loop system simulation model,analysis the effect of main parameters on dynamic character of counterbalance combination valve during the rise and drop of the bidirectional rocking arm,according to the simulation results,the design parameters are optimized.Lastly,this dissertation carried on the experiment of counterbalance combination value,the testing data and theoretical analysis was almost same,the results indicated that the theoretical analysis was accurate,can meet the engineering application requirements.After the study of short wall shearer counterbalance combination valve,it can remove dithering and additional resistance,and enhance the stability of the hydraulic system,has extensive application prospect. |
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