Authors

Abstract

In view of the fact that the threshing gap of combine harvester can only be controlled by adjusting gravure screen and it is time-consuming and laboring, a kind of variable-diameter threshing drum with movable radial plates is developed by changing the diameter of threshing drum to adjust the threshing gap concentrically. All parts of the threshing drum were designed and checked by mechanical design principle, and the statics and modal analysis of the whole structure were carried out by ANSYS Workbench. The results show that the maximum deformation of the variable-diameter threshing drum with movable radial plates is 0.29 mm under boundary conditions. The maximum allowable deformation of the threshing drum in use is 3 mm, which meets the requirements of use. The equivalent stress of the threshing drum with variable diameter is up to 100 MPa, which is less than the yield strength of the material, and will not cause structural damage. According to the modal analysis, the natural frequency of the threshing drum does not cause resonance phenomenon. The field test of wheat was carried out after the processing of the variable-diameter threshing drum with movable radial plates was installed, and the working performance was compared with that of the ordinary drum. The results showed that the threshing performance was the best when the forward speed was 1 m/s, the grain entrainment loss rate was 0.53%, and the grain un-threshed rate was 0.065%. The grain breakage rate is 0.54%, and the performance is more than 50% higher than that of ordinary rollers. It lays a foundation for the adaptive adjustment of threshing gap in combine harvester.

Abstract in Chinese

针对目前联合收获机脱粒间隙只能调节凹版筛来控制且费时费力，研制了一种通过改变脱粒滚筒直径同心调节脱粒间隙的辐盘移动式变直径脱粒滚筒，同时对脱粒滚筒直径变化对脱粒性能的影响进行了分析。利用机械设计原理对脱粒滚筒进行了所有部件的设计校核，并利用ANSYS Workbench 对整体结构进行了静力学和模态分析, 结果表明, 在边界条件下幅盘移动式变直径脱粒滚筒的最大变形量为0.29 mm，小于脱粒滚筒在使用中允许最大变形量为3 mm，符合使用要求，变直径脱粒滚筒等效应力最大为100 MPa，小于材料的屈服强度，不会产生结构的损坏。根据模态分析, 脱粒滚筒的固有频率不会造成共振现象, 将加工好的辐盘移动式变直径脱粒滚筒安装后进行了小麦的田间试验, 并与普通滚筒进行作业性能对比，结果证明 , 在前进速度为1 m/s时, 脱粒性能最好. 夹带损失率为0.53%, 未脱净率为0.065%, 破损率为0.54%, 性能较普通滚筒相比提升50%以上。为联合收获机脱粒间隙自适应调节奠定了基础。