鲜食玉米柔性采摘低损集穗收获割台设计与试验

Design of and experiment on fresh corn flexible picking and damage-free collectting harvest header

【目的】设计一种鲜食玉米柔性采摘低损集穗收获割台,为鲜食玉米机械收获减损提供参考。【方法】设计一种两级过渡切削式拉茎辊,对摘穗过程进行运动学分析,拉茎辊与拨禾带尺寸及工作参数范围及切削式拉茎辊中心距取值范围91.65~107.00 mm,基于Hertz-Mindlin with bonding接触模型的离散元仿真分析拉茎辊中心距合适值在102 mm左右及拉茎辊采用交错刀式装配,以便有效减少因茎秆被扯断导致含杂率高。测试两种不同材质橡胶拨禾带耐疲劳性及橡胶拨禾带主要失效形式。【结果】设计了一种柔性采摘低损集穗收获割台,橡胶拨禾带主要失效形式为内圈传动齿磨损、拨禾带体断裂和外圈拨禾齿疲劳开胶,加氧化锌的丁腈橡胶拨禾带有更好抗磨损和抗疲劳性能。有效防止了因果穗磕碰搅龙叶片导致的籽粒损伤,在试验中籽粒破损率减小了0.08%。机器前进速度为7.2 km/h,拉茎辊中心距为103 mm,拉茎辊转速为700 r/min时作业效果最好。【结论】优化后试验平均籽粒破损率为0.368%,平均含杂率为0.43%,优于行业标准。

【Objective】A flexible harvesting and low-destructive header harvesting platform for fresh-food corn is to be designed.This finding can provide reference for mechanical harvesting loss reduction of fresh corn.【Methods】A two-stage transitional knife rolls was designed.Kinematic analysis of picking process was carried out to get the size and working parameters range of knife rolls and puller belt.Through theoretical analysis,the range of center distance of cutting knife rolls.Through discrete element simulation based on Hertz-Mindlin with bonding contact model,the suitable value of center distance of knife rolls.The knife rolls was assembled with staggered knife.It effectively alleviated the problem of high impurity content caused by excessive broken stalks.Through fatigue resistance test on two different kinds of rubber poking belts,and it was concluded.【Results】Designed a flexible harvesting and low-destructive header harvesting platform for fresh food corn.The main failure modes of rubber poking belts were wear of inner ring drive teeth,fracture of poking belt body and fatigue opening of outer ring poking teeth,and better wear and fatigue resistance of nitrile rubber poking belts with zinc oxide.A low-loss heading device was designed to effectively prevent damage caused by impact of causal spikes on stirrer blades,and the grain breakage rate was reduced by 0.08%.Through field orthogonal test and optimization,it was concluded that the forward speed of the machine was 7.2 km/h,the center distance of the knife rolls was 103 mm and the speed of the knife rolls was 700 r/min.【Conclusion】The average grain breakage rate and the average impurity content are 0.368%and 0.43%,respectively after optimization,which are better than the industry standard.