木薯收获机夹持输送机构设计与力学分析

摘要

针对现有挖拔式木薯收获机夹持输送机构出现夹持掉带掉薯、夹持对中困难及木薯茎秆难以进入夹持输送机构等问题，研究设计了夹持输送机构。该机构采用拉簧安装在移动杆凹槽内，移动杆与机架间为移动副连接的方式夹紧木薯茎秆，并将其与摇杆与机架间为转动副连接的方式进行了对比分析。结果表明：移动副连接使拉簧的拉力全部提供为夹持力，无拉力损失，夹持力最大；同时，自动调节带间距，夹持牢固。根据土薯生物环境特性，设计了夹持轮、带轮、夹持带、张紧装置和导向装置等主要结构，并对各结构进行了分析，确定了主要结构参数。根据木薯块根拔起时的速度分解图，建立了块根拔起时的力学模型，且通过分析推导得到了夹持输送机构对块根的拔起力和对茎秆的夹持力计算公式。该研究对于快速拔出、输送薯块、减少薯块损失、降低伤薯率、提高挖拔式木薯收获机整机性能具有重要意义。%Aiming at the existing problems of dropping off during clamping,dropping off of cassava,difficulty to clamp in the middle point,difficulty to feed cassava stem to clamping-conveying mechanism of digging-pulling cassava harvest,a kind of clamping-conveying mechanism is designed.Tension-spring is installed inside a shift rod groove.The cassava stem is clamped tightly between wheels being installed the shifting rod and frame.The shifting rod can shift on the frame by shifting pair.Compare with the revolving pair between the rocker and frame,the shifting pair make the power of ten-sion-spring turn to clamping-power fully,no any loss,get maximum clamping force.At the same time the spacing of two belts can be adjusted automatically,and the cassava stem may be clamped firmly.According to the biological and environ-mental characteristics of cassava,main structure such as clamping-wheel,belt-wheel,clamping-belt,tensile mechanism and guiding mechanism are designed.Each structure are analyzed, and some main structure parameters are determined. According to the speed decomposing diagram of pulling cassava roots,the mechanism model is established,and the calcu-lation formula of pulling force to root and clamping force to stem were got.This research has great significance of high-speed pulling root and conveying stem,decreasing roots loss,reducing the injury rate of cassava,improving performance of digging-pulling cassava harvester.