Abstract:
Abstract: In order to improve the blocking issue of logistics system in sugarcane harvester, by the methods of simulation analysis and experimental research, the cutter spiral lifting mechanism and the effects of friction coefficient and working parameters on the sugarcane material flow were studied and discussed. The average residence time of sugarcane in the transmission device of the screw conveyor was considered as test index and the virtual prototype simulation model was established by the software ADAMS and Unigraphics. Simulation results indicated that increasing friction coefficient of cutter spiral lifting mechanism could improve the delivery rate of the sugarcane and effectively inhibit the clogging problem. The high-speed photography results of experimental prototype showed that while a tyre rubber with high friction coefficient was used as the covering layer for the cutter spiral lifting mechanism and the cutter speed was about 750 r/min, the retention time of sugarcane was shortened by 17% compared to original rebar spiral lifting mechanism. This characteristic could improve the congestion problem of logistics system, and verify that the friction coefficient was exactly the main affecting factor. Based on this principle, this paper worked out the structure improvement of the cutter spiral lifting mechanism. The helical circular cross section was changed into a helical rectangular cross section, which made the contact way of the cutter spiral lifting mechanism and sugarcane change from point contact originally to line contact. The computer simulation experiments under different structures' transmission speed, displacement, force and so on were conducted, and the analysis indicated that for the 20 mm cutter spiral lifting mechanism that was improved, the sugarcane residence time was shortened by 32% comparing with the original cylindrical spiral. Meanwhile, after the sugarcane head entered the spirals, the loading time from the spiral to the sugarcane head relatively decreased and the time of the loading process was shorter, and the universal impact force for the sugarcane was bigger, which made the cane's feeding into the system more easily and rapidly. Before the sugarcane tail left the spiral, the favorable impact from spiral still existed, its impulse changed by 11.1 N·s, and the backward displacement of the sugar cane increased. And in the comparison of different width of spiral plane, the spiral retention time of sugarcane decreased by 18.5% when the plane width increased from 12 to 20 mm. If the width of spiral plane continued to increase to 24 mm, the trapped time of sugarcane increased by 17.6% compared to 20 mm width. When sugarcane tail left the spiral, the spiral with 12 and 24 mm width would have an adverse impact on sugarcane, which was unfavorable to the sugarcane conveying, while the spiral with 16 and 20 mm width would not only make the time of cane heading into the spiral shorter, but also produce more favorable impact when sugarcane tail left the spiral. Consequently, the experimental results showed that it could increase the friction conveying force and reduce the sugarcane retention time by appropriately widening the cutter spiral lifting mechanism width. It was advantageous to improve the transportation performance of sugarcane. Compared with 16 mm wide spiral, 20 mm wide spiral offered the equivalent total impulse after the sugarcane head entered the spiral. That made it easier for the sugarcane to enter the feeding roller, and before the sugarcane's tail left the spiral, the loading time from the spiral to the sugarcane's tail was more concentrated, the impact force was more balanced, and the backward transmission of the sugarcane was faster and more stable, which could effectively restrain the blocking problem of the front end of conveying system. The results provide the design basis for the construction of the late test platform and the development of the physical prototype.