甘蔗收获机切段装置设计与试验

Design and Experiment of Chopper Device in Sugarcane Harvester

针对甘蔗收获机切段装置存在的切段机理理论缺乏、切段损失大、对切段装置要求多样化等现状,对比分析了切段装置前置式、中置式、后置式3种形式的收获流程,并基于对前置切段式结构的理论分析,推导前置切段式切段长度的经验公式,设计了切段装置试验台和切段装置前置式收获机割台。进行了切段过程高速摄影试验,获知蔗段在切段过程中的运动规律、蔗叶与蔗茎的分离形式、断口糖分损失的主要形式及原因,通过田间正交试验确定了影响蔗段合格率因素主次顺序为:交错深度、行驶速度、切段辊转速,当交错深度为4 mm,行驶速度为2 km/h,切段辊转速为300 r/min时,割台蔗茎合格率达到93%。通过统计学分析计算,得出了长度系数为0.7,其长度分布近似符合正态分布规律。

Aiming at the status that the mechanism study of the chopper device in sugarcane harvester is insufficient,chopping loss is high,and the requirements to the chopper device present the character of diversification,three different harvest processes varied in the mounting position of the chopper device were compared and analyzed,including front-mounted,central-mounted and rear-mounted. Based on the analysis result of the merit and demerit between different harvest processes,the viewpoint that the harvest process which adopted front-mounted structure of chopper device was more suitable for the bending and lodging sugarcane in China was proposed. Further theoretical analysis of the front-mounted structure was conducted and empirical formula of billet length produced under this structure was deduced. Based on this,a chopper testing unit was designed, as well as a new type header of sugarcane harvester charactered by front-mounter chopper. A high-speed photography test was conducted on the testing unit and law of motion of billets and cane-stalk was observed,as well as the separation process between stalk and leaf,furthermore,sugar loss during chopping process was analyzed through the procedure of fracture formation. Taking the billet acceptability as index,and through orthogonal field test conducted on the header,the factors impacted on billet quality were optimized,and the billet acceptability reached up to93% under the condition that intersect depth was 4 mm,ground speed was 2 km/h,and rotational speed of rollers was 300 r/min. By means of billet length test and statistical analysis,a conclusion was drawn that billet length was approximately in normal distribution,and the length coefficient in aforesaid formula was deduced as 0. 7.