谷物平面清选筛驱动机构的设计说明书.doc

谷物平面清选筛驱动机构的设计说明书
JIANGXI AGRICULTURAL UNIVERSITY
本科毕业论文(设计)
题目: 谷物平面清选筛驱动机构的设计
学院:姓名: 学号:
专业: 农业机械化及其自动化
年级: 指导教师: 职称:讲师
二0一三年五月
摘要
当前全球进行谷物清选主要采用筛选、空气动力选、表面特性选、比重选等几种方式。这其中, 运用最多的一种形式是筛选,其使谷物在筛面上运动,利用其不同的尺寸形状的特征,把混合物分成通过筛孔和不能通过筛孔的两部分,即将谷物群体中的大小杂物清除,而保留饱满成熟谷粒。筛体的运动轨迹是影响谷物清选净度的重要因素。
本设计采用按谷物厚度分离的长孔筛进行谷物清选,筛体只需要作横向水平振动即可。为了保证振动筛具有良好的筛分性能和较高的生产率,第一,该使谷物从落料口落到筛面上之后,散开的宽度增加,提高有效的筛分面积。第二,还必须使谷物以及杂物能够在筛选过程中能够不断的后移至出料口。为此本设计的筛体运动轨迹为:筛体在物料下落处作平面圆周运动, 随后慢慢地由平面圆周运动变为平面椭圆运动,其短轴逐渐变小,在筛体末端过渡到往复直线运动。这种运动轨迹能够使物料下落后不
产生堆积现象而均匀地分布在筛面上,使物料能充分地与筛面接触进行筛选,而后快速地沿筛面前移,达到提高筛分效率的目的。
关键字: 清选驱动平面振动
Abstract Current global grain cleaning mainly adopts filter, air power to choose, surface features, such as proportion of selected several ways. It, a form is most often used to screen, it makes the grain movement on the screen, use the different size of shape characteristic, divide the mixture into through the mesh and not through the screen mesh of two parts, the grain size of the group clear debris, and keep full ripe grains. Sieve body movement is the important factors that affect grain cleaning clarity.
This design adopts the thickness according to the grain separation of long hole grain cleaning sieve, sieve body you just need to make lateral horizontal vibration. To ensure that the vibrating screen has a good sieving performance and higher productivity, first, it makes the grain from the blanking hole after fall on the screen, the width of the scatter increase, increase the effective screening area. Second, must also enables grain and sundries in the screening process can continuously moved to discharge port. Therefore this design sieve body trajectory as follows: the sieve body in the materials falling plane circular motion, then slowly changed from plane circular motion to planar elliptical motion, the short axis gradually e smaller, in the end of the screen body transition to reciprocating linear motion. This trajectory can make the material behind does not prod