刨花振动筛运转工况下主结构振动应变测试与分析

Vibration strain test and analysis of main structure of particle swing screen under operating conditions

振动筛在所有刨花筛分机械中占据绝对优势,但随着振动筛的结构加大和振动强度的提高,振动筛会出现工作频率低、动态平衡性差、疲劳寿命较短等问题。以BF14260刨花振动筛为研究对象,在拟定的典型工况下,在刨花振动筛筛箱横梁位置选取了多组测点,并利用DH5922D动态信号测试分析系统对测点进行了测试与分析。试验结果表明,刨花振动筛在电机启动后各位置会增加正向或负向偏置静态应变,停机后偏置静态应变会消失。筛箱横梁上下边缘应变明显大于中间位置,且以水平方向和斜向45°为主,主要承受横向弯曲及剪切交变应变,同时最下侧横梁处应变相比其余2处横梁应变更大,以最下侧横梁在前后支撑腿间部分应变变化最显著,极易出现疲劳破坏。因此,整体支撑梁龙骨结构应重新进行优化设计,进一步降低最下侧梁易破坏区域应变,同时应适当调整其余2处横梁以提升其应变承受能力。研究结果为刨花振动筛的优化设计,特别是为降低复杂工况下大型刨花振动筛的整机振动和提高疲劳寿命提供了参考。

Due to its simple structure,heavy workload and high reliability,the vibrating screen has placed high on the list of all particle screening machines.However,as the structure of the vibrating screen is customized and the vibration intensity is increased,it leads to problems such as low operating frequency,poor dynamic balance and short fatigue life of the vibrating screen.The BF14260 particle swing screen is the first large-scale particle swing screen in China.Due to the lack of theoretical basis and experience accumulation,the vibrating screen also has the above problems in the operation process.This study takes BF14260 particle swing screen as the research example.Under the proposed typical working conditions,multiple sets of measuring points were selected at the beam position of the particle swing screen box,including the comparative test of the same beam at different horizontal positions and the comparative test of different beams at the same vertical position,and used the DH5922 D dynamic signal test and analysis system to analyze the measuring point group.The analysis results showed that the particle swing screen would increase the positive or negative bias static strain at each position after the motor was started,and the bias static strain would disappear after its shutdown.The strains on the upper and lower edges of the screen box beam were obviously greater than the middle position,and the horizontal direction and the oblique direction were mainly 45°,and they were mainly subjected to transverse bending and shear alternating strain.At the same time,the strain at the lowermost beam was greater than those of the other two beams.Among them,the strain on the lowermost beam between the front and rear supporting legs was the most significant,and fatigue failure was extremely likely to occur.Therefore,the overall supporting beam keel structure should be optimized again to further reduce the strain in the vulnerable area of the bottom side beam,and at the same time,the remaining two beams should be adjusted appropriately to improve its strain tolerance.Even through the strain test of the vibrating screen under working conditions,the strain distribution on the beam of the vibrating screen box could be accurately obtained.The research results provided a reference for the optimization design of the particle swing screen,especially the reduction of the vibration of the large-scale particle swing screen under complex working conditions and the improvement of the fatigue life.