4LZ-1.5型大豆联合收获机设计与试验

为实现国内大豆大田生产低损收获同时兼顾大豆育种小区收获，该研究设计了4LZ-1.5型大豆联合收获机，针对大豆成熟期易炸荚的特性，分析了大豆拨禾作业过程，建立了拨禾轮结构和运动参数求解模型，并对拨禾轮半径、拨禾速度比、拨禾轮转速等参数进行优化；针对大豆结荚低、收割易铲土的特性，分析了大豆籽粒尺寸参数统计规律，并对割台除土机构进行优化；针对大豆成熟期易脱粒、易破碎特性，对脱粒分离装置、清选装置和气力卸粮装置进行优化；针对育种小区收获要求，建立了清种装置曲柄摇杆机构数字化设计模型，确定了清种装置结构参数。分别进行大田生产和育种小区收获试验，结果表明，大豆大田生产收获的损失率<3.5%，破碎率<1.5%，含杂率<1%；大豆育种小区收获的损失率<3%，破碎率<1.5%，含杂率<1%，混种率<0.2%，清种时间200～270 s，满足大豆大田生产和育种小区收获作业要求。与现有大豆收获机械相比，4LZ-1.5型大豆联合收获机收获损失率降低1.5%～5%、破碎率降低3.5%～6.5%、含杂率降低2%～7%，研究结果可为后续大豆收获机结构改进和作业参数优化提供参考。

Design and experiments of the 4LZ-1.5 soybean combine harvester

Abstract: Soybean is one of the most important grains and oil crops in China, due to a major source of oil and high-quality vegetable protein. It is very necessary to realize the low-loss harvest of soybean fields in the southern and Huanghuaihai regions. In this study, a 4LZ-1.5 type combine harvester was designed to consider the harvest of soybean breeding plots. The operation process was also theoretically analyzed for the soybean reel harvesting, according to the soybean pods easy to be fried at maturity. A numerical model was established for the reel structure and motion parameters. Some parameters were then optimized, such as the reel radius, reel speed ratio, and reel rotational speed. After that, the soil removal mechanism was optimized for the soybeans with the low pods and easy-to-shovel soil, according to the statistical parameters of soybean grain size. Furthermore, a soybean threshing and separation device was designed for the easy threshing and breakage of soybeans at maturity. The arrangement and distribution of the arch teeth were also determined via the increasing characteristics of the second-order arithmetic sequence. The angle of the deflector was adjusted for the various input amount. The blade fan-combined screen cleaning device was designed to optimize the structural parameters of the fan and cleaning screen. The pneumatic grain unloading device was designed to optimize the vortex fan. The plot harvesting required the high soybean mixed seeding, particularly for the breeding plot with a small planting scale and many varieties, compared with the field production. Frequent seed cleaning was required after harvesting to reduce the missed and mixed seeding, according to the harvest requirements of the breeding area. An optimization mathematical model was established to develop the seed cleaning device, together with the objective function and constraint conditions. A numerical simulation was then carried out using MATLAB, in order to determine the structural parameters of the seed-cleaning device. A series of comparative experiments in field harvesting were conducted in the Xinjiang Uygur Autonomous Region, Shandong province, and Hebei province of China. The better operating performance was achieved in the 4LZ-1.5 soybean combine harvester: the loss rate < 3.5%, broken rate < 1.5%, and impurity rate < 1%, fully meeting the soybean harvest requirements in most hilly areas. After harvest testing of 14 soybean varieties in a 3m×6m breeding plot, the test results were all achieved: the loss rate < 3%, broken rate < 1.5%, impurity rate < 1%, mixed seed rate < 0.2%, and the clearing time of 200-270 s, fully meeting the requirements of the harvesting operation indicators in the breeding plots. Compared with the existing soybean harvesting machinery, the harvest loss rate of 4LZ-1.5 soybean combine harvester was reduced by 1.5%-5.0%, the broken rate was reduced by 3.5%-6.5%, and the impurity rate was reduced by 2.0%-7.0%. The findings can provide a strong reference for the structural optimization of operating parameters in soybean harvesters.