点刹递进式棉包缠膜系统设计与试验

Design and Experiment of Point-braking Type Film Wrapping System of Round Baler Cotton Picker

针对国产圆包式采棉机棉包缠膜技术理论研究不足,存在送膜不畅、包边效果不好等问题,设计了一种点刹递进式棉包缠膜系统,主要由送膜机构、点刹拉紧机构和控制单元组成。通过研究棉包点刹拉紧缠膜机理,理论分析了送膜的必要条件、导向器上膜成功的有效区域、以及棉包端部包边形成的边界条件,确定了影响点刹递进式棉包缠膜系统作业性能的主要因素为打包带速度、点刹周期、制动时间与进膜时间比值(制动比),以平均棉包包边宽度、平均棉包密度为试验指标开展了三因素三水平二次回归响应面试验,建立了回归模型,分析各因素对棉包缠膜系统作业性能的影响,得到了点刹递进式棉包缠膜系统最佳工作参数为:打包带速度156 r/min,点刹周期1200 ms,制动比为1.2,以此参数组合进行验证试验,得到棉包的平均包边宽度为160 mm,平均棉包密度193 kg/m^(3),试验结果与理论优化值相差不超过5%。

In view of the insufficient theoretical research on the existing cotton bale wrapping technology and the issues include frequent blockage in the film feeding process and poor edging effect in domestic round baler cotton picker,a point-braking type film wrapping system was designed.The system mainly consisted of film feeding device,point-braking tensioning device,and control unit.By studying the film wrapping mechanism of cotton round bales,the necessary conditions for film feeding,the effective area of successful film feeding on the guide device,and the boundary conditions for the formation of edge wrapping at the ends of the cotton package were theoretically analyzed.A three-factors,three-levels quadratic regression orthogonal test was conducted with packing belt speed,point-braking cycle,the ratio of braking time to film feeding time(referred to as the braking ratio)as the test factors,and the average edge width of the cotton package and the average cotton bale density as the test indexes.A regression model was established to analyze the impact of each factor on the film wrapping system.The optimized working parameters was as follows:packing belt speed of 156 r/min,point-braking cycle of 1200 ms and braking ratio of 1.2.The combination of these parameters was tested in the field,the average edge width was 160 mm and the average cotton bale density was 193 kg/m^(3).The experimental results differed from the theoretically optimized values by less than 5%.The research results can provide reference for the design of cotton packaging and harvesting machinery.