免耕播种机无轴螺旋排肥输肥装置设计与试验

Design and Experiment of Shaftless Spirals Fertilizer Discharging and Fertilizer Delivery Device of No-tillage Planters

针对西南地区坡度较大、免耕地表秸秆及根茬等造成耕地平整度较差,驱动式破茬防堵免耕播种机作业时机具整体产生振动较大,导致排肥器排肥及导肥管导肥作业性能差的问题,基于螺旋输送原理,设计了一种柔性无轴螺旋排肥输肥装置。通过对肥料的螺旋输送以及物料临界输送速度分析,得出螺旋叶片最佳充肥尺寸以及转速范围。采用EDEM仿真进行二次回归正交旋转试验和响应曲面法分析无轴螺旋排肥输肥装置最佳工作参数:螺旋叶片内半径3 mm、螺旋叶片外半径12.8 mm、螺旋叶片转速319 r/min以及螺旋间距24.5 mm。田间测试结果表明,在地表平整度平均值以及地表坡度分别为8.9 cm、16.1°时,无轴螺旋排肥输肥装置在作业速度1.5 m/s时,排肥精度误差、均匀性变异系数分别为1.87%、2.52%,满足国家施肥标准,播肥符合当地农艺要求。所设计的无轴螺旋排肥输肥装置满足免耕播种施肥要求,可为在地表平整度较差时排肥和振动较大条件下排肥器以及导肥管的设计与改进提供参考。

Aiming at the operation of driven stubble breaking and blocking no-tillage planter in Southwest China,due to poor flatness caused by the large slope,no-tillage surface straw and stubble,stubble breaking and blocking operation of the machine produced vibration as a whole,which resulted in poor performance of the fertilizer discharger and fertilizer guide tube,based on the principle of spiral conveying,a shaftless spiral fertilizer discharging and fertilizer conveying device was designed.Through the calculation of shaftless spiral conveying volume per unit time,the factors affecting the device discharge volume were analyzed.According to agronomic requirements,the amount of fertilizer required per unit time was calculated.And through the critical conveying speed and flow characteristics of material,the working parameters of shaftless spiral fertilizer conveying and fertilizer transfer device range were determined.Then the optimal size of the spiral blade fertilizer filling as well as the range of rotational speeds was obtained.The quadratic regression orthogonal rotation test was carried out by using EDEM simulation,and the response surface method was used to analyze the working parameters of the shaftless spiral fertilizer discharge and transfer device.Then the optimal parameters were obtained as follows:the shaftless radius was 3 mm,the radius of the spiral outer axis was 12.8 mm,the rotational speed of the blade was 319 r/min,and the rotational pitch of the spiral was 24.5 mm.Based on data above,the device was manufactured and its field performance was tested.The results showed that when the average value of the surface flatness was 8.9 cm and the slope of the surface was 16.1°,the fertilizer discharge performance of the shaftless spiral fertilizer transfer device was better than that of the external grooved wheel fertilizer discharger,and the error of fertilizer application accuracy and the coefficient of variation of uniformity were 1.87%and 2.52%,respectively,under the operating speed of 1.5 m/s.At 0.5 m/s and 1 m/s operation speed,the fertilizer application precision error and uniformity coefficient of variation all met the national fertilizer application standard.The designed shaftless spiral fertilizer discharging and conveying device met the requirements of no-tillage sowing and fertilizer application,and it can provide reference for the design and improvement of fertilizer discharging device and fertilizer conduit under the conditions of poor surface flatness and long-distance fertilizer conveying.