油菜收获机割台螺旋输送器间隙自适应调节机构研究

Clearance Adaptive Adjusting Mechanism for Header Screw Conveyor of Rape Combine Harvester

针对油菜联合收获过程中由于喂入量波动导致割台螺旋输送器堵塞的问题,设计了一种割台螺旋输送器间隙自适应调节机构,实现喂入量变化时实时改变滑块位移以自动调节输送器与底板之间的间隙。输送器动力学与运动学分析确定了调节机构预紧弹簧最大预紧力和调节位移分别为366 N和50 mm。运用扭矩传感器和高速摄像技术分别开展输送器扭矩和调节位移的性能试验,当弹簧预紧力和刚度分别为293 N和12.65 N/mm时,输送器扭矩为8.267 N·m,减少了40.7%,调节位移为10.2 mm,调节机构性能较优。调节机构对输送器性能影响试验结果表明:增设间隙自适应调节机构可明显降低扭矩并增加最大喂入量,螺旋输送器转速为150 r/min时扭矩减小了23%;转速为200 r/min时,最大喂入量增加至3.5 kg/s,提高了16.7%。喂入量在不大于3.0 kg/s范围内波动时,试验组最大扭矩小于对照组,说明调节机构可较好适应喂入量的波动。田间试验表明间隙自适应调节机构可提高输送器对喂入量的适应性,避免割台堵塞,后续的脱粒装置、清选装置等工作部件未发生堵塞,油菜联合收获机可正常工作。

Aiming at solving the blocking of screw conveyor on header of rape combine harvester,an automatic clearance adjusting mechanism was designed. The maximum pretension and displacement were determined to be 366 N and 50 mm,respectively,through statics and kinematics analyses of the screw conveyor. Torque sensor and high-speed camera technique were used respectively to record torque on the shaft of conveyor and displacement,parameters tests of the mechanism were conducted and the results indicated when pretension was 293 N and stiffness was 12. 65 N/mm,maximum torque of conveyor was8. 267 N·m,which was decreased by 40. 7%,maximum displacement of the slider was 10. 2 mm,and parameters of adjusting mechanism were optimal. The influence of the adjusting mechanism on performance of conveyor tests showed that adding the adaptive adjusting mechanism could obviously reduce torque and increase maximum feed quantity,when speed was in range of 150 ~ 300 r/min,the feed quantity was 1. 5 ~ 3. 5 kg/s. Torque was decreased by 23% when speed was 150 r/min,feed quantity was increased by 0. 5 kg/s in experimental group,which was increased by 17. 8%. When feed quantity was fluctuated from 1. 0 kg/s to 3. 0 kg/s and 1. 0 kg/s and from 3 kg/s to 1. 0 kg/s and 3. 0 kg/s,maximum torque was decreased compared with steady feeding quantity of 3 kg/s. Field experiment showed that the clearance adaptive adjusting mechanism could adjust the clearance between screw conveyor and bottom plate in time according to the change of feed quantity during harvesting operation,therefore,it could improve the adaptability of header to fluctuation of feed quantity and relieve blocking.