双通道喂入式再生稻收获机研制

针对再生稻的头季稻机械化收获和低碾压率收获需要,该文设计了一种双通道喂入式再生稻收割机,主要由履带式底盘、割台、2套左右对称布置的脱粒清选装置和秸秆粉碎器、粮箱及动力与传动系统等组成。基于再生稻头季稻机械收获稻茬碾压模型确定其割幅为3000 mm,底盘轨距1500 mm,履带宽度400 mm,履带接地长度1800 mm。对双通道割台、秸秆粉碎器等关键部件进行设计分析,确定搅龙中部2个螺旋叶片起始位置的周向夹角为180°、秸秆粉碎器排草尾板外侧板倾角为8.2°、内侧板倾角为6°、上盖板与垂直方向夹角为63°。田间试验结果表明:该机作业速度可达0.8 m/s,喂入量4.6 kg/s,总损失率2.1%,含杂率0.4%,破碎率0.2%。直行碾压率26.7%,作业性能稳定,作业过程顺畅,尾部秸秆粉碎器可将碎秸导入履带碾压区。与现有常规收割机相比,该机可使再生稻头季稻的直行碾压率降低16.2%,可使再生季每公顷增产23.9%。该研究可为长江中下游地区再生稻机械化收获技术与装备研究及推广提供参考。

Development of double-channel feeding harvester for ratoon rice

As one of the rice varieties, ratoon rice has the advantages of making full use of temperature and light resources, saving seed, labor, water and pesticide, improving land use efficiency, increasing production and income. The first crop of ratoon rice is often harvested in wet and soft soil and requests high stubble and low rolling rate and degree. However, the rolling rate of common harvester is as high as 40%-50%, which seriously affects the yield of ratoon rice, resulting in significant reduction of economic benefits of ratoon rice production. According to the needs of mechanized harvest and low rolling rate of first crop of ratoon rice, a double-channel feeding harvester for ratoon rice was designed according to the growth characteristics of ratoon rice based on previous researches and theoretical methods proposed by the research group. The machine was mainly composed of a tracked chassis, a header, two sets of threshing and cleaning devices and straw crushers which were bilateral symmetry, a grain bin, an engine and transmission system, and the harvester could realize the process of straw separating, plant-poking, cutting, transporting, threshing, cleaning, straw crushing, grain transporting, grain holding and grain unloading in one time. Compared with the common harvester, by adopting the structure that two sets of working parts share one walking chassis, the weight of the double- channel feeding harvester for ratoon rice was reduce and the damage degree of rolling on the rice stubble was low. According to the harvest rolling model of ratoon rice harvester, the structural parameters were set as the cutting width was 3 000 mm, the track gauge was 1 500 mm, the track width was 400 mm and the grounding length was 1 800 mm. A special header with two channels was designed, which shortened the distance of straw transportation, mitigated the blocking of header, and effectively balanced the power consumption and reduced the vibration by transferring the power separately. Two sets of independent telescopic finger mechanism was adopted which could avoid deformation due to long eccentric shaft, and it was determined that the initial circumferential angle of the two spiral blades in the middle of the two-way spiral conveyor was 180° based on the theoretical analysis. To ensure that the long straw after threshing and cleaning was crushed and scattered to the harvested area, by analyzing the scattering range of straw crusher, it was ascertained that the inclination angle of the outer plate of the tail plate was 8.2°, the inclination angle of the inner plate was 6°, and the angle between the upper cover plate and the vertical direction was 63°. Longitudinal axial threshing cylinder was adopted for threshing. Through analyzing the rolling rate and productivity, it was determined that the available volume of grain bin was 1.5 m3, which could hold 900 kg grain. Harvesting performance was tested according to relevant standards, the major performance evaluation indicators consisted of working speed, feeding rate, loss rate, impurity rate, crushing rate and productivity. The PL60 4LZT-6.0ZC1 harvester of ZOOMLION was used as a contrast. It was suggested from the field test that this machine had stable performance and smooth operation. The tail straw crusher could guide the broken straw into the rolling area, the working speed could reach 0.8 m/s, the feeding rate was 4.6 kg/s, the total loss rate was 2.1%, the impurity rate was 0.4% and the crushing rate was 0.2%. The straight rolling rate was as low as 26.7%, which was 16.2% lower than that of the contrast. The yield of ratoon rice in the first season was 10 175.4 kg/hm2, the yield in the second season was 6 013.5 kg/hm2, and the total yield in the first and second season was 16 188.9 kg/hm2. In control area harvested by the common harvester, the yield of ratoon rice in the first season was 10 175.4 kg/hm2, the yield in the second season was 4 854.6 kg/hm2, and the total yield in the first and second season was 15 030 kg/hm2. Compared with the common harvester, the yield increased by 23.9% (1 158.9 kg/hm2) in the second crop harvested by the double-channel feeding harvester. This research could provide valuable reference for the research and extension of ratoon rice mechanical harvesting technology in the middle and lower reaches of Yangtze River.