水稻插秧机异形非圆锥齿轮宽窄行分插机构研究

针对现有旋转式高速宽窄行分插机构取秧过程总传动比无法进一步增大而限制了对秧针直取秧姿态作出进一步改善的问题,提出一种基于球面节曲线的异形非圆锥齿轮传动机构,与交错齿轮组合成空间行星轮机构并应用于高速宽窄行分插机构中。以首尾连接两段光滑的非均匀B样条曲线建立封闭的异形非圆锥齿轮节曲线理论模型,调节节曲线过渡段齿形高度以实现齿轮连续传动。建立了分插机构理论模型,分析了异形非圆锥齿轮对插秧轨迹形状与姿态的影响。基于优化后的结构参数建立了分插机构三维模型和加工实物模型,分别对机构仿真轨迹和速度以及高速摄影获取的试验插秧轨迹和速度进行对比分析,同时,完成了基于旋转土槽的实际栽插试验,验证了分插机构建模的正确性以及机构的可行性。最后,通过与斜齿交错-非圆锥齿轮行星系宽窄行分插机构的插秧轨迹速度进行对比,得出该机构在取秧过程具有更优的直取秧动作。

Wide-narrow Distance Transplanting Mechanism with Special Shaped Non-circular Bevel Gears for Rice Transplanter

In order to obtain a spatial planetary gear train with higher transmission ratio, which can shorten the large horizontal offset of picking seeding trajectory, a kind of special shaped non-circular bevel gears based on spherical curve was put forward, and a wide-narrow distance transplanting mechanism composed of special shaped non-circular bevel gears and crossed cylindrical gears was obtained. The pitch curve of special shaped non-circular bevel gears was designed by two non-uniform B-splines which had continuous angles and discontinuous radius. The gear pair could continuously and smoothly work after adjusting the height of tooth profile curve in the transition section of two non-uniform B-splines. The theoretical model of wide-narrow distance transplanting mechanism was built up. An optimization program was finished, and the effect of the different shape of special shaped non-circular bevel gears to the wide narrow distance planting trajectory was analyzed. A three-dimensional model was built up by computer, and an actual physical model was processed. The shapes and speeds of the planting trajectory which formed by the two models were compared, and the values of measuring parameters were almost the same. A test with seeding by transplanting mechanism was carried out based on rotary trial soil bin. Speed comparison between the transplanting mechanism composed of special shaped non-circular bevel gears and transplanting mechanism composed of non-circular bevel gears was made, and the result showed that the wide-narrow distance transplanting mechanism composed of special shaped non-circular bevel gears had the advantages in shortening the large horizontal offset of picking seeding trajectory, and the planting trajectory was better.