采煤机截割部齿轮箱体振动特性实验

截割部在割煤作业中同时受截割煤岩体冲击载荷以及由内部齿轮啮合引起的高频激励,是采煤机可靠性的薄弱部位,得到准确的截割部振动响应是进行可靠性分析进而提高截割部可靠度的最重要前提。基于国家能源采掘装备实验中心进行截割实验。实验台按照煤矿综采工作面搭建,能够真实模拟井下采煤全过程;根据综采工艺,实验工况设置为空载、直行截割及斜切截割,得到齿轮箱体振动加速度数据并进行时域和频域分析;探讨了截深、牵引速度和煤层硬度等关键参数对截割部齿轮箱体振动特性的影响。将实验结果与理论计算进行比较;结果表明:理论计算结果与实验吻合较好;垂直地面方向振动量最大,振动幅值随截深、牵引速度和硬度而增加;斜切截割中出现拍振现象,拍振随截割载荷增大而减小;齿轮系统各传动级啮合频率发生耦合现象,耦合频率构成了优势频率的主要部分;截割部齿轮箱体的振动主要由齿轮系统啮合非线性振动引起,频率耦合会产生更多激振频率成分从而增大箱体发生共振的可能性。实验得到的数据和相关结论对正确认识采煤机截割部振动响应规律及截割部的可靠性分析和设计具有参考价值。

Tests for dynamic characteristics of shearer cutting gearbox

Here, dynamic characteristics of shearer cutting gearbox (SCG) were investigated with tests based on the national coal mining equipment test center. A test platform was constructed according to a fully mechanized coal mining face to actually imitate downhole coal mining process. According to the fully mechanized mining technique, test working conditions were set as no-load, straight line cutting and oblique one to acquire vibration acceleration data of gearbox, perform analyses in time domain and frequency one for these data, and explore effects of cutting depth, traction speed and hardness of coal layer, etc. key parameters on dynamic characteristics of SCR. A finite element model of SCG was established to do numerical simulation. The simulation results were compared with the test ones. Results showed that both results agree well with each other;vertical vibration of cutting head is the maximum, vibration amplitude increases with increase in cutting depth, traction speed and hardness;beat phenomena occur in oblique cutting process and these phenomena decrease with increase in cutting load;coupling phenomena among meshing frequencies of various transmission stages in gear system happen, coupled frequencies become the main parts of dominant frequencies;vibration of SCG is mainly caused by gear system mesh nonlinear vibration, frequencies coupling can cause more exciting frequency components to increase the possibility of local resonance of SCG;the study results provide a reference for design and reliability analysis of SCR.