再生稻收割机刚柔耦合杆齿脱粒装置的设计与试验

目的 针对再生稻头季收获时籽粒和秸秆含水率较高，籽粒与稻穗的黏结力较大，采用传统刚性杆齿脱粒装置的收割机收获时会导致大量籽粒破碎的问题，在轴流式脱粒滚筒的基础上设计了一种刚柔耦合杆齿的脱粒滚筒。方法 采用EDEM仿真软件对脱粒过程进行仿真模拟，通过后处理获得3种不同杆齿(刚性、柔性、刚柔耦合)对籽粒的平均法向打击力和切向揉搓力；以夹带损失率、破碎率和未脱净率为评价指标，分别以不同滚筒转速下的单因素和以滚筒转速、水稻籽粒含水率、杆齿种类为因素的三因素三水平进行不同杆齿的正交台架验证试验。结果 EDEM仿真结果表明，在滚筒转速分别为650、750和850 r/min时，3种杆齿对籽粒的平均法向打击力和切向揉搓力均表现为刚性杆齿最大、柔性杆齿最小。单因素试验结果表明，刚性杆齿脱粒装置的籽粒破碎率明显高于柔性杆齿脱粒装置和刚柔耦合脱粒装置，在滚筒转速为900 r/min时，柔性杆齿、刚性杆齿和刚柔耦合杆齿的破碎率均很高，分别为1.632%、1.925%和2.564%；柔性杆齿脱粒装置的未脱净率和夹带损失率明显高于刚性杆齿脱粒装置和刚柔耦合脱粒装置，在滚筒转速为900 r/min时，柔性杆齿、刚性杆齿和刚柔耦合杆齿的未脱净率均很低，分别为0.286%、0.071%和0.240%，在滚筒转速为850 r/min时，柔性杆齿、刚性杆齿和刚柔耦合杆齿的夹带损失率均很低，分别为1.595%、0.729%和1.341%。正交试验结果表明，影响籽粒夹带损失率和破碎率的因素顺序依次为杆齿种类 > 滚筒转速 > 籽粒含水率，影响未脱净率因素的顺序依次为杆齿种类 > 籽粒含水率 > 滚筒转速。结论 相同条件下，刚柔耦合脱粒装置能够在保证籽粒脱净率的前提下，降低籽粒破碎率。研究结果可为再生稻收割机脱粒装置的设计与田间应用提供参考。

Design and experiment of rigid-flexible coupling rod tooth threshing device of harvester for ratooning rice

Objective In response to the problem of high moisture content of seed and straw, high bonding force between seed and rice spike at the first harvest season of ratooning rice, there will lead to large amount of broken seeds when harvested by harvesters with traditional rigid rod-tooth threshing device, a rigid-flexible coupled rod-tooth threshing drum based on the axial flow threshing drum was designed.Method The EDEM discrete element simulation software was used to simulate the threshing process, and the average normal striking force and tangential kneading force of three different rod teeth (rigid, flexible, and rigid-flexible coupling) on seeds were obtained through post-processing. Using entrapment loss, breakage rate and unclean rate as the evaluation indexes, the orthogonal bench validation tests were carried out with different drum speed as single factor, and three factors (drum speed, seed moisture content, and rod teeth type) and three levels.Result The EDEM simulation results showed that the average normal striking force and tangential kneading force of the three types of rod teeth on seeds were the largest for the rigid rod teeth and the smallest for the flexible rod teeth at the drum speeds of 650, 750 and 850 r/min, respectively. The results of single-factor test showed that the broken rate of seeds threshed by the rigid rod tooth threshing device was significantly higher than those of the flexible rod tooth and the rigid-flexible coupling threshing devices. The broken rates of the flexible rod tooth, rigid rod tooth and rigid-flexible coupling rod tooth were very high at 900 r/min, with the broken rates of 1.632%, 1.925% and 2.564%, respectively. The unthawed rate and the entrained loss rate of the flexible rod tooth threshing device were significantly higher than those of the rigid rod tooth and the rigid-flexible coupling threshing devices. The unthreshing rates of the flexible rod tooth, rigid rod tooth and rigid-flexible coupling rod tooth were very low at 900 r/min, with the unthreshing rates of 0.286%, 0.071% and 0.240%, respectively. The entrainment loss rate of the flexible rod tooth, rigid rod tooth and rigid-flexible coupling rod tooth were very low at 850 r/min, with the entrainment loss rates of 1.595%, 0.729% and 1.341%, respectively. The results of orthogonal test showed that the order of factor affecting seed entrainment loss and broken rate was rod tooth type > drum speed > seed moisture content, and the order of factor affecting the uncleaned rate was rod tooth type > seed moisture content > drum speed.Conclusion Under the same conditions, the rigid-flexible coupling threshing device can reduce the rice breaking rate while ensuring the seed removal rate. The results can provide a reference for design and application of threshing device of harvester for ratooning rice.