三移动两转动振动筛驱动机构优化与试验

Optimization and Experiment on Driving Mechanism of Vibrating Screen with Three Translations and Two Rotations

为提高玉米脱出物在振动筛上的筛分效率,基于传统的平面往复振动筛,设计了一种玉米清选振动筛驱动机构,可使筛面实现3个移动2个转动;为深入研究其运动规律和筛分性能,用封闭矢量多边形法推导了筛面上任意一点的位移方程;以筛面后端振幅最小为目标,应用Isight软件优化各驱动杆件的长度,使筛面后端的振幅达到最小值15.4 mm;利用Matlab数值模拟确定筛面运动为非简谐周期运动。为确定驱动机构主轴转速和玉米脱出物喂入量对振动筛性能的影响,通过试验比较玉米籽粒在该机构筛面与平面往复振动筛面上的透筛率,试验结果表明,当玉米脱出物的喂入量为6 kg/s时,该机构主轴的最佳转速为260 r/min,玉米籽粒在该机构筛面上的透筛率比其在平面往复振动筛上的透筛率提高了5.75%,节省功耗16.1%。

Vibrating sieve for corn cleaning is a vital component of corn harvester. To further improve the screening efficiency of corn threshed mixture on the screen, a new type of driving mechanism of vibrating screen for corn cleaning was designed, in which three translations and two rotations of the screen can be realized based on the plane reciprocation mechanism with only two translation. To obtain the motion laws and screening performance of the screen, the displacement equation of any point on the screen were derived by using the closed vector polygon method. The lengths of each drive rod were determined by using optimal design of the software Isight. The optimization objective was that the displacement of the screen in the rear would be minimum. The back amplitudes of the screen optimized was 15.4 mm. Combining Matlab software,the results of numerical simulation showed that the motion of the mechanism was cyclical and not simply harmonic. Comparative experiment was conducted on the new type of driving mechanism and the plane reciprocation mechanism. Sieving rate of corn particles penetrated the sieve with high-speed camera was recorded, under the condition of different speeds of spindle and the mass of corn threshed mixture. In the experiments, the mass percentages of corn kernels, corn stalks, corncob and light mixture were 73.3% ,17.6% ,8.7% and 0.4% , respectively. The conclusion was drawn that the optimized speed of spindle was 260 r/min when the maximum feed mass was 6 kg/s. The corresponding sieving rate was increased by 5.75% and energy consumption was reduced by 16. 1%. The superiority of this new organization was proven. The research result provided a theoretical basis for designing more reasonable cleaning mechanism to improve the production efficiency.