多源激励对联合收获机螺栓连接处振动特性试验研究

Experimental Study on Vibration Characteristics of Bolt Joint of Combine Harvester under Multi-source Excitation

联合收获机各部件通过螺栓及其连接件相连,在工作过程中互相影响、互为激励源并且冲击、磨损和不平衡碰撞较为严重。研究了螺栓连接处松动程度及主要振动,提取了工作过程中联合收获机主要工作部件螺栓及连接件处响应时域特征,分析了螺栓及其连接件主频及倍频响应。结果表明,在正常工作过程中振动筛边缘螺栓各时域特征数值均处于极高水平,并且频率成分也较为复杂。其余测点频率集中主频34.7195 Hz及倍频无明显边频带产生,但振动筛螺栓除本身主频2.302 Hz及其高倍频外,不受发动机转频及其倍频影响。可以得出,振动筛螺栓连接处受载最严重与复杂,为振动筛处螺栓及连接件防松和失效在线监测奠定了基础。

Various components of combine harvester are connected by bolts and their connectors,which affect and excite each other during working process,and have severe impacts,wear,and unbalanced collisions.Degree of looseness and main vibration at bolt connections was studied,time-domain characteristics of main working components of combine harvester during working process were ex-tracted,and main frequency and harmonics response of bolts and their connections were analyzed.Results indicated that during normal operation,time-domain characteristic values of edge bolts of vibrating screen were at extremely high levels,and frequency components were also relatively complex.Main frequency of other measurement points was 34.7195 Hz,and there was no obvious sideband gener-ated in frequency doubling.However,vibration screen bolts were not affected by engine rotation frequency and its doubling frequency,except for their own main frequency of 2.302 Hz and its high doubling frequency.It could be concluded that bolt connection of vibrating screen was subjected to the most severe and complex load,laying foundation for online monitoring of bolt and connector loosening and failure at vibrating screen.