掉齿对带锯条横向振动最大Lyapunov指数的影响

Influence of Sawtooth Shedding on Maximum Lyapunov Exponent of Lateral Vibration of Band Saw Blade

以MJ3210A型木工跑车带锯机为研究对象,使用信号采集分析仪采集不同工况下带锯条横向振动位移,计算、分析带锯条横向振动最大Lyapunov指数,找出带锯条掉齿与最大Lyapunov指数关系.由正交试验结果可知:负载下影响MJ3210A型跑车带锯机带锯条横向振动位移的显著因素依次为锯轮主轴转速、进料速度、锯条张紧力.在最优工作条件下,由锯轮转速、带锯条张紧力、跑车进料速度、锯路高度对带锯条横向振动的Lyapunov指数影响结果看,空载下完好带锯条、空载下有掉齿缺陷带锯条、负载下有掉齿缺陷带锯条3种工况下的最大Lyapunov指数分布范围界限非常明显,因此可以根据最大Lyapunov指数范围判定带锯条工作负载状况和产生掉齿缺陷故障状况;掉齿数量对带锯条横向振动最大Lyapunov指数影响十分明显.随着掉齿数量的增加,带锯条横向振动最大Lyapunov指数急剧增加;随着木材硬度的提高,有掉齿缺陷带锯条最大Lyapunov指数也随之增加,由此也可以根据最大Lyapunov指数和加工原料树种判断负载状况及掉齿缺陷产生及发展状况;在最优工作条件下,本试验将带锯机工作59.2 h作为判断掉齿故障阈值时间.在判断带锯条故障种类及发展程度上,带锯条横向振动最大Lyapunov指数法要好于横向振动位移法和横向振动主频率法.

Taking the MJ3210 A woodworking sports car band saw as the research object,the signal acquisition analyzer is used to collect and analyze the lateral vibration displacement of the band saw blade under different working conditions,and calculate the maximum Lyapunov exponent of the band saw blade lateral vibration to find the band saw blade and the largest Lyapunov exponent. From the orthogonal test results,it can be seen that the factors affecting the lateral vibration displacement of the band saw blade of the MJ3210 A sports car band sawmachine under load are the spindle wheel speed,feed speed and saw blade tension. Under the optimal working conditions,the effect of the saw wheel speed,band saw blade tension,sports car feed speed,and sawing height on the Lyapunov exponent of the lateral vibration of the band saw blade shows that the band saw blade is intact under no load and there is no load under no load. The maximum Lyapunov exponential distribution range of the sawtooth defect band saw blade and the sawtooth loss defect band saw blade under load is very obvious.Therefore,the band saw blade workload condition and the sawtooth defect condition can be determined according to the maximum Lyapunov exponent value range. The number of missing teeth has a significant influence on the maximum Lyapunov exponent value of the lateral vibration of the band saw blade. With the increase of the number of teeth,the maximum Lyapunov exponent value of the band saw blade increases sharply. With the increase of the hardness of the wood,the band saw blade with the sawtooth loss is the largest. The Lyapunov exponent value also increases so that the load condition and the occurrence and development of the sawtooth loss can be judged according to the maximum Lyapunov exponent value and the processing of the raw material species. Under the optimal working conditions,this test will use the band saw machine working time of 59. 2 h as the judgment time threshold of the sawtooth loss. In determining the type and development degree of band saw blade failure,the maximum lateral vibration of the band saw blade Lyapunov exponent method is better than the lateral vibration displacement method of the band saw blade and the lateral vibration main frequency method of the band saw blade.