基于人工击打脱粒原理的食葵脱粒装置设计与试验

针对食葵脱粒作业缺少专用机械装备、籽粒破损率高等问题，该研究基于人工击打脱粒原理，设计了一种食葵脱粒装置，脱粒时食葵盘面朝下模拟翻盘动作，锤杆被脱粒弹簧向上推动完成击打脱粒作业，借助输送带差速设计完成转盘作业。首先根据食葵盘及籽粒的物理特性，对脱粒部分及输送机构的结构参数进行设计和优化；再通过理论分析确定了影响未脱净率、破损率的关键因素。并试制了食葵脱粒装置试验台，以击打频率、脱粒通道间隙、弹簧压缩量为试验因素，以未脱净率、破损率为试验指标开展正交试验，确定了较优工作参数组合。结果表明：脱粒过程中，影响食葵盘未脱净率、籽粒破损率的因素主次顺序为击打频率、脱粒通道间隙、弹簧压缩量，较优工作参数组合为击打频率44次/min、脱粒通道间隙78 mm、弹簧压缩量25 mm，在较优参数组合下进行重复验证试验，结果表明，食葵未脱净率、籽粒破损率分别为8.12%、0.65%。研究结果可为食葵机械脱粒装备的研制提供参考。

Design and experiment of the edible sunflower threshing device based on manual threshing principle

Abstract: Edible sunflower is one of the most important economic crops in China. It is also highly required for the plumpness and shape of edible sunflower seeds, in order to serve as the snack foods after processing. As such, manual and mechanical threshing can be commonly used for the processing of edible sunflower seeds at present. Among them, there is the low rate of grain damage during manual threshing, but the low threshing efficiency and the high labor intensity. Mechanical threshing presents the high threshing rate of edible sunflower, but there is a serious grain damage, where a grain threshing drum can be mostly adopted to utilize the bar or bow tooth for the threshing operation. Therefore, it is a high demand to balance the threshing operation for the high quality of edible sunflower seeds. Furthermore, it is still lacking on the specific mechanical threshing equipment for the edible sunflower seeds other than the oil sunflower. In this study, a bionic hammer threshing device was developed to simulate the manual threshing process for the low rate of grain damage and the high threshing rate of edible sunflower. A static and dynamic analysis was also made to explore the mechanism of grain loss in the threshing process. Specifically, the sunflower disk was faced down to simulate the overturning action during threshing. The threshing spring was used to push upward the hammer rod for the threshing operation. A conveyor belt differential design was conducted to realize the rotary table operation. The structural parameters of threshing parts and conveying mechanism were optimized, according to the physical characteristics of edible sunflower plate and grain. A theoretical analysis was also made to determine the optimal factors for the rate of non-depuration and damage. The test-bed of edible sunflower threshing device was trial produced to verify the simulation. The orthogonal test was carried out to determine the optimal combination of better working parameters, particularly with the hitting frequency, threshing channel clearance, and spring compression as the test factors, while the non-threshing rate and damage rate as the test indexes. The results showed that the primary and secondary order of the factors affecting the non-threshing rate of edible sunflower plate and the grain damage rate were the hitting frequency, the threshing channel gap, and the spring compression amount in the process of bionic threshing. The optimal combination of working parameter was achieved with the hitting frequency of 44 times/min, the threshing channel gap of 78 mm, and the spring compression amount of 25 mm. The verification test was carried out under the optimal combination of parameters. The results showed that the non-threshing rate of edible sunflower and the grain damage rate were 8.12% and 0.65%, respectively. Moreover, the rate of non-depigmentation was higher, whereas, the damage rate was lower, fully meeting the harvest standard of edible sunflowers. The findings can provide a strong reference to develop the mechanical threshing equipment for the edible sunflower.