【摘要】 研究钢辊式圆捆机卷捆过程的理论尚待完善,尤其卷捆过程的关键环节(旋转草芯形成过程)需进一步深入研究。为此,将多场耦合理论引入钢辊式圆捆机卷捆过程分析中,构建卷捆过程的多场耦合函数模型,并基于分析结论对卷芯过程进行试验研究。理论分析表明:钢辊式圆捆机(无切割喂入机构)打捆时,在摩擦动力场、推力场及摩擦阻力场的耦合作用下完成卷捆过程,影响摩擦动力场的主要因素为重力场、张力场及钢辊与打捆物料间摩擦因数,影响推力场的主要因素为喂入量,影响摩擦阻力场的主要因素为打捆物料与卷捆室侧壁间压力及二者间摩擦因数。据此,进行草捆张力测量试验和旋转草芯形成试验。试验结果表明:在长宽比(稻秆与卷捆室宽度的比值)为1的试验条件下,旋转草芯形成时的草芯密度范围为31.09～37.28kg·m-3,草芯密度约45kg·m-3时张力场开始出现,张力场随草芯密度增加呈先缓慢增加后快速上升的趋势,旋转草芯形成时张力场尚未产生,促进草芯转动的摩擦动力场主要依赖草芯重力而产生,且其强度较弱;钢辊与稻秆间摩擦因数的增幅值大于0.223时,旋转草芯形成时的草芯密度发生显著性降低;长宽比为0.8和1.2时,增大喂入量(在机器喂入能力范围内)对旋转草芯形成时的草芯密度无显著影响,长宽比为1.0时,增大喂入量可在一定程度上降低旋转草芯形成时的草芯密度;长宽比对旋转草芯形成时的草芯密度具有极显著影响,旋转草芯形成时的草芯密度随长宽比的增大而增大。更多还原

【Abstract】 Up to now, theories obtained from studies on the baling process of steel roller-type round balers remain to be perfected, particularly, the theories with regard to the key links of the bailing process(formation process of rotating straw core)need to be further clarified by more in-depth studies.Therefore, the multi-field coupling theory was introduced into the baling analysis of the steel-roll round baler, thereby constructing the baling coupling function model, and experiment was conducted according to the analysis results of theory.Theoretical analysis shows that when the steel-roll round baler(feeding mechanism without cutting) was operated, the baling was completed under the coupling effects of frictional dynamic field, thrust field and frictional resistance field. The main factors affecting the friction dynamic field include gravity field, tension field and friction factor between the steel roll and the baled materials. The main factor affecting the thrust field is the feeding quantity. The main factors affecting the frictional resistance field are the pressure between the bundling material and the side wall of the bundling room and the friction factor between them. At that time, straw-bale tension measurement test and rotating straw-core formation test were performed respectively in this paper. According to the results of both tests, at a length-width ratio(ratio of length of rice straw to width of roll-box) of 1, straw-core density ranged from 31.09 to 37.28 kg·m-3 during the rotating straw core formation, then tension field began to appear when straw-core density increased to about 45 kg·m-3, and showed a tendency of slow rising followed by rapid increasing with the increase of the straw-core density. The tension field was not formed in the midst of the formation of rotating straw core.The formation of the friction dynamic field was mainly subject to the gravity of straw core, and the intensity was weak. When the amplification of friction factor between the steel roll and the straw was more than0.223, the density of the core was significantly reduced in the midst of the formation of rotating straw core.When the length-width ratio(ratio of the length of the straw to the width of the baling chamber) is 0.8 and 1.2, an increase in feeding quantity(within the feeding capacity of the baler) has no significant impact on core bale density in the midst of formation of rotating straw core. When the length-width ratio is 1.0, the core bale density in the midst of formation of rotating straw core decreases to some extent as the feeding quantity increases. The length-width ratio has an immensely significant impact on the core density in the midst of formation of rotating straw core, which increases as the former increases. This study can provide a theoretical and technical basis for the design of round baler with steel roll and the optimization of its operational parameters.更多还原