汽车衡安装误差对称重精度的影响分析

Analysis on influence of truck scale installation error of weighing accuracy

利用准静态分析方法研究偏载对汽车衡称重精度的影响,偏载越严重,称重值越小,误差越大.柱式负荷传感器安装的初始倾斜造成传感器偏斜承载,由力的平衡关系求得的各传感器偏斜角度之和随荷载移动保持不变.由材料力学公式计算秤台随荷载移动的变形量,表明作用在秤台上的荷载越大,上压头和传感器偏载越大.秤台倾斜安装角度超过临界角度时,利用静力学平衡原理得到倾斜角度越大,弹性体高度越大,球头半径越小,偏载越大.通过有限元软件分析柱式负荷传感器安装标高误差对各传感器支承点上压头转角随荷载移动的变化过程,结果表明标高差越大,各支承点上压头转动角度变化幅度越大,偏载越严重.当标高差过大时将处于三点支承状态,减小秤台承载刚度,秤台变形增大.最后,给出可提高秤台刚度和控制偏载的相关措施.

Quasi-static analysis method was used to study the influence of eccentric load on weighing accuracy of truck scale. The more serious the eccentric load is, the smaller the weighing value is and the greater the error is. Initial tilt of the column load sensors produced eccentric load, and the sum of deflection angle of each sensor keeps constant with the load movement according to equilibrium relation of force. The deformation of scale with the motion of the load was calculated by the material mechanics formula. It shows that the larger the load on scale, the greater the eccentric load of the upper pressure head and the sensor is. When the angle of the tilt scale is more than the critical angle by the principle of static balance, the larger the tilt angle, the greater the height of the elastomer and the smaller the radius of the ball, the greater the eccentric load will be. The change process of the upper pressure head angle with the motion of the load on the support point of each sensor was analyzed by the finite element software. The result shows that the greater the elevation difference, the greater the change of the angle of the upper pressure head on each supporting point, and the more serious the eccentric load is. When the standard height difference is too large, the scale will be in the three-point supporting state, which reduces the bearing rigidity of the scale and increases the deformation of the scale. Finally, the relevant measures to improve the rigidity of the scale and to control the eccentric load were given.