基于离散元法的料门式给料器料门受力研究

Force Analysis of the Material Door of Door-form Feeding Mechanism Based on Discrete Element Method

目的研究料门式给料器工作中颗粒物料对料门的作用力,以便选择合适的驱动机构。方法对给料器结构进行合理简化后,利用离散元法借助PFC3D软件,仿真计算料门完全关闭时受颗粒物料的作用力;将料门及实现其转动的辅助机构合理简化为杆件机构,分析料门在几个关键位置所需的驱动力。结果颗粒物料对料门垂直方向的合力始终小于其自身的重力,而且随着颗粒物料高度的增加此现象会变得更加明显;料门受到颗粒物料的正压力和切向静摩擦力,随着料斗内料位高度的增加最初呈线性增大,后转为非线性并趋于极限值,而且变化过程与料斗结构也有一定关系;料门在完全关闭状态打开料门所需的摆动臂驱动力约为115 N,在精给料时维持精给料位置所需限位臂驱动气缸的推力约为553 N。结论设计料门式给料器时只需计算一定料位高度的料门受力,超过此高度后物料继续增多时料门受力基本不变;使用的料门式给料器采用的气缸驱动力足够大,能够保证正常工作。

The aim of this work was to research the force of granular material in door-form feeding mechanism on the material＇ door, so as to choose appropriate drive mechanism. After reasonable simplification of the feeding mechanism structure, PFC3D based on DEM was used to calculate the force on material door exerted by granular material when the material door was completely closed, then the material door and its associated mechanism were simplified into bar mechanism, and the required driving force in several key positions of the material door. The results showed that the vertical direction force suffered by the material door was always smaller than the material gravity, and this phenomenon became more significant with increasing material height. The positive pressure and tangential static friction of the door suffered from material increased linearly with the increase of material height, then increased nonlinearly, and final it tended to approach a limit value. This change had a relationship with the structure of hopper. When the door was fully closed, the oscillating lever force required to open the door was about l15N. At the accurate feeding position, the limiting lever force required to maintain the accurate feeding was about 553N. When designing door-form feeder mechanism, the force suffered by the material door was only needed to be calculated at a certain material height, with further increase of material height the force of material door suffered from material kept almost constant. In the feeding mechanism used in this paper, the cylinder could provide sufficient driving force to ensure the proper functioning of the mechanism.