纵轴流联合收获机双层异向清选装置设计与试验

Design and Experiment of Double-layered Reverse Cleaning Device for Axial Flow Combine Harvester

针对传统纵轴流联合收获机清选系统单层筛架在作业过程中存在大喂入量下损失率和含杂率高等问题,设计了一种结构紧凑、清选能力强、清选效果好的双层振动清选装置,提出了双层异向独立振动的玉米籽粒清选方式,分析确定了筛面和物料的运动规律、清选筛和双风道的结构参数以及传动机构的运动参数。以籽粒含杂率、籽粒损失率和分布比例为评价指标,对曲柄转速进行单因素试验,确定最佳工作参数为上曲柄转速220 r/min、下曲柄转速190 r/min;选取上筛曲柄长度和下筛曲柄长度为试验因素,进行了两因素三水平正交试验,确定较优组合为:上、下筛曲柄长度分别为50 mm与40 mm。在较优水平组合下,以8 kg/s的喂入量进行验证试验,试验结果表明籽粒损失率为0. 45%,籽粒含杂率为0. 76%,籽粒分布比例为1. 92%,清选效果较好,能满足清选性能要求。

Due to the existing problems of high loss rate and impurity rate when corn grains are directly harvested by the cleaning device of vertical flow threshing device with high feed volume,a double-layer vibration system with compact structure,strong cleaning ability,good cleaning effect and high reliability was designed. A double-layered independent vibrating cleaning method of corn grain was proposed. The movement law of screen surface and material was determined through analysis,the structural parameters of cleaning screen and double air duct and motion parameters of the transmission mechanism were obtained. Based on three evaluation indicators of the grain impurity rate,grain loss rate and distribution ratio,single-factor tests were conducted on the crank speed to determine the best operating parameters with upper and lower crank speeds of 220 r/min and 190 r/min,respectively. With two factors of crank length of upper and lower screen and three levels of 40 mm,45 mm and 50 mm,the orthogonal test was carried out to acquire the optimal cleaning results that the crank lengths of upper and lower screen were50 mm and 40 mm,respectively. Finally,under the above experimental conditions,the results showed that the grain loss rate,grain impurity ratio and grain distribution ratio were 0. 45%,0. 76% and1. 92%,respectively,when the feed rate was 8 kg/s,and the cleaning effect of the device was better,which can meet the cleaning performance requirements.