盘刀式铡草机粉碎物料运动过程分析与试验

为了探究盘刀式铡草机粉碎物料的抛送运动规律，该研究在综合考虑抛送装置与前端装置的参数匹配及气流对物料的影响下，将物料抛送运动过程分为7个阶段，通过分析物料在各个阶段的运动及受力情况，建立了物料从切碎到与叶片碰撞、物料沿抛送叶片运动、沿抛送直管和弯管运动以及物料被抛出出料口后的动力学模型。以动力学模型为基础，建立了数值计算模型。根据实测的铡草机与物料相关数据，确定了仿真模型参数，以物料的抛送距离为评价指标，分析了主轴转速和叶片倾角对抛送性能的影响。研究结果表明，在试验范围内，抛送距离随着主轴转速的增大而近似线性增大；随着叶片倾角的增大，抛送距离呈先增大后减小的趋势，且后倾叶片的抛送距离大于前倾叶片，后倾叶片更有利于物料运动。抛送距离试验得到的结果与理论仿真结果一致，最大相对误差为6.6%，验证了动力学模型的合理性。动力学模型的建立为进一步优化抛送装置结构和运动参数及其与前端装置的匹配提供理论指导。

Analysis and experiments of the movement process for the shredded material of disc knife chaff cutter

Throwing device is an important factor that directly affects the performance of chaff cutter. For the problem of low throwing efficiency and residue blockage of disc knife chaff cutter, scholars at home and abroad have done a lot of research, but most of the previous research is based on simulation and experimental research. For the movement of materials, theoretical analysis studies are rarely performed. Most scholars only analyze the movement of material in the throwing device separately, and ignore the influence of the front-end device and airflow on the material. Therefore, this study aims to establish a more complete theoretical analysis model to provide a theoretical basis for the design of the whole machine of the chaff cutter. A kinetic analysis method was proposed to reveal the laws of material throwing motion of the disc knife maize. Material movement process were divided into seven stages in the whole throwing process, according to the matching between the throwing device and the front-end device, and the influence of airflow on the material. The movement and force of the material were analyzed in each stage. The kinetic model of the material movement along the throwing blade, along the throwing straight and elbow, and after throwing out of the outlet was established, using the initial and final velocity of each stage to connect adjacent stages. Based on the dynamic model, the throwing distance of the material was taken as index value, and a numerical calculation model was established using MATLAB software. The parameters related to the maize straw material involved in the simulation and calculation process, including moisture content, mass and diameter, were measured by physical tests. The airflow velocities in the throwing tube at different working conditions were measured using a TSI9565 anemometer, and the average value (0.203) of the coefficient of friction between the maize straw material and the tube wall was obtained using a CNY-1 inclinometer. The parameters of simulation model were determined according to the actual structural parameters of the 9Z-6A disc knife chaff cutter and the test data related to the maize straw material, and the influence of the spindle speed and blade inclination angle on the throwing performance was analyzed. The results showed that the throwing distance increased approximately linearly with the increase of the spindle speed during the test range. The throwing distance first increased and then decreased, with the blade inclination angle increased. The maximum throwing distance was obtained when the length of the shredded material was 12 mm, the blade inclination angle is 7° and the spindle speed was 700 r/min. The results obtained from the throwing distance test were consistent with the trend of the theoretical simulation results, with a maximum relative error of 6.6%, which verified the accuracy of the dynamic model. The findings can provide a theoretical basis for the structural design, parameter optimization, and matching of the chaff cutter.