穗茎兼收型玉米收获机茎秆切碎与输送装置设计与试验

Design and Test of Stalk Chopping and Conveying Device for Corn Combine Reaping both Stalk and Spike

针对玉米收获时秸秆回收困难、利用率低的问题,设计了一种穗茎兼收型玉米收获机,对茎秆切碎和输送装置进行了详细设计。通过比较,采用转子铣刀切割器作为茎秆切断装置,运用ANSYS/LS-DYNA对转子铣刀刀片厚度、转速、刃角进行了三因素三水平的正交试验,试验表明铣刀转速为1 400 r/min、刀片厚度为7 mm、刃角为20°时功耗最小;设计了具有不同齿形和转速的单层多辊式输送器,并通过理论分析建立了4输送辊线速度之间的关系;对茎秆切碎装置进行了设计,确定动定刀位置和理论切碎长度。最后对样机进行了田间试验,结果表明:实际茎秆切碎长度与理论切碎长度无显著差异(P≤0.05),样机各项指标满足设计和行业相关标准要求。

Through the research analysis of corn harvester status at home and abroad as well as market demand of the current corn harvester,a new type of corn harvester for the stalk chopping and conveying device reaping both corn stalk and spike were designed emphatically. The advantages and disadvantages of different types of cutter were compared and analyzed,the cutting performance and function of feeding were considered,then the rotor milling cutter was adopted as the stem cutting device. To explore the power consumption influence factors of rotor milling cutter,the 3D simulation software ANSYS / LS-DYNA was used and a three-factor and three-level orthogonal simulation test of the rotor rotating speed,thickness and the blade angle was carried out. The simulation results showed that the rotational speed and blade angle on the level of P≤0. 10 had significant effects on power consumption for corn stalks cutting,and the thickness of the blade on the level of P ≤ 0. 10 had less influence however. Through the simulation,the best working parameters of rotor milling cutter was determined as the blade speed of1 400 r / min,thickness of 7 mm and blade angle of 20°,and on this occasion the power consumption was minimum. The single stem feeding device and double stem feeding device were compared and analyzed,and the transmissions were considered in as well,the transmissions of single stem feeding device were simpler. Then different tooth profiles and different speeds of roller conveyors were designed,and the relationship between four conveying rollers linear velocity was established by theoretical analysis,providing basis for transmission design. The different types of stem cutter were compared and analyzed,and rotary chopper was adopted. Then the drum diameter,blade installation form,dynamic location weredesigned and calculated,and through calculating,the theoretical length of stalk chopped was 34. 6 mm.Finally,the field experiment was carried out. Results showed that the feed rate was 4. 06 kg / s,operation speed was 1. 2 m / s,and the average stubble height was 9. 5 mm,coefficient of variation was 6. 32%.The stem length curve was drawn,and the actual chopped stalks length was between 0 ~ 40 mm and percent of pass was 95%. The average real chopped length was 35. 2 mm and had no significant difference with the theory chopped length 34. 8 mm in the level of P≤0. 05. At the same time,the other indicators of the harvester meet the design and relevant national standards.