针对实际生产中油菜机械铺膜穴播缺乏穴粒数精确可控排种器的问题，设计了一种采用负压吸种、正压卸种、鸭嘴成穴、二次投种的油菜正负气压组合式穴播器，实现油菜机械铺膜穴播1~3粒的作业要求。建立吸种、携种和卸种过程种子的力学模型并结合FLUENT仿真分析，分析确定了油菜正负气压组合式穴播器结构及其参数；选取影响穴播器排种性能的负压、种层高度、排种轮主轴转速和正压开展了以穴粒数合格率、空穴率为试验指标的穴播器排种性能单因素试验，并按照响应曲面法的二次正交旋转中心组合试验开展了工作参数的优化和验证。试验结果表明：影响穴播器穴粒数合格率的因素主次顺序为负压、排种轮主轴转速、正压，穴播器最佳排种性能工作参数组合为排种轮主轴转速7.5 r/min、负压-2 000 Pa、正压850 Pa。台架验证试验结果表明，穴播器的穴粒数合格率(1～3粒)为88.15%，空穴率为4.43%，满足油菜机械铺膜穴播的要求。
In order to solve the problem of the lack of accurate and controllable seed metering device for mechanical film mulching and hole sowing of rapeseed in actual production,a combined device of positive and negative pressure for rapeseed was designed,which adopted negative pressure seed sucking,positive pressure seed unloading,duck mouth hole forming and secondary seed feeding,so as to meet the requirements of 1-3 seeds for mechanical film mulching and hole sowing of rapeseed. By establishing the mechanical model of seed sucking,seed carrying and unloading process and combining with FLUENT simulation analysis,the structure and parameters of the combined positive and negative pressure seeding device for rapeseed were determined.The negative pressure,the height of seed layer,rotation speed of seed metering wheel spindle and positive pressure were selected to carry out the single factor test of seed metering performance with the right rate of seeds per hill and rate of no seed hill as the test index,and the optimization and verification of working parameters were carried out according to the quadratic orthogonal rotation center combination test of response surface method. The results showed that:the primary and secondary factors affecting the right rate of seeds per hill were negative pressure,rotation speed of seed metering wheel spindle and positive pressure.The optimal working parameters of seed metering performance was rotation speed of seed metering wheel spindle at 7.5 r/min,negative pressure at -2 000 Paand positive pressure at 850 Pa.The results of bench verification test showed that the right rate of seeds per hill (1-3) was 88.15%,and the rate of no seed hill was 4.43%,which met the requirements of rapeseed production requirements of mechanical film laying and hole sowing. This study provides a reference for the improvement of rapeseed seed metering device structure.