4SY-1.8型自走式油菜割晒机机架振动特性的分析
Analysis of vibration characteristic of 4SY- 1.8 self-propelled rape windrower frame

针对4SY-1.8型油菜割晒机因受往复式切割器动刀运动激振力随机不定而引起机架振幅大的问题，分析引起割台各个部位振动幅值不同的成因，开展基于割刀驱动轴采用液压马达驱动且转速无级可调时割刀驱动轴扭矩J和割刀驱动轴消耗功率W的测试分析； 应用模态仿真分析法获得机架的前20阶固有频率和振型，并运用锤击法验证模态仿真分析的正确性； 应用RBF神经网络拟合各测试点平均振动位移峰峰值F与割刀驱动轴扭矩J、模态分析第1阶总变形值B和割刀驱动轴转速n的函数关系，得出各层神经元权值并检验模型的正确性。结果表明：机架测试点平均振动位移峰峰值F与割刀驱动轴转速n的拟合关系符合指数分布，显著性均大于0.944。
To deal with the problem that 4SY-1.8 rape windrower worked with large frame amplitude because of the random and uncertain exciting force of the reciprocating cutter the movable knife, the causes were analyzed that led to different vibration amplitudes in various parts of the cutting table. Based on the characteristics that the cutter drive shaft was driven by hydraulic motor and its speed was infinitely adjustable, the torque and the power consumption of the cutter drive shaft were tested. The top twenty natural frequencies and mode shapes of the frame were obtained by modal analysis simulation. The correctness of modal analysis simulation was verified by hammering method. The functional relationship between the cutter drive shaft torque, the cutter shaft rotational speed, the first order total deformation values of modal analysis and each test point average peak vibration displacement were fitted by RBF neural network. Neurons weights of each layer were obtained and the correctness of the RBF neural network model was tested. Results show that the fitting relations between frame test point average peak vibration displacement and cutter shaft rotational speed conformed to the exponential distribution and the correlation coefficient were higher than 0.944. 