挠度加凸补偿提高折弯件精度的研究

Investigation on Improving Accuracy of Bending Workpiece with Crowning Compensation Method

为解决C型折弯机加载过程中因结构变形导致的折弯件全长方向角度不一致的问题,应用Timoshenko梁理论建立了折弯加载解析模型,考虑形状、尺寸以及惯量等因素对折弯精度的影响,推导了折弯机滑块和工作台的变形机理,获得了变形一般规律:滑块和工作台的叠加变形曲线可用一元四次方程表述;固定点处的挠度与载荷成正比。在分析常用的挠度补偿方法的基础上,提出了楔块式挠度补偿方法。针对某款折弯机,结合理论计算结果和楔块补偿法设计了一种挠度补偿装置。试验对比发现采用此装置后的折弯件角度偏差控制在±25′范围内,小于未采取补偿的±1°,高出国标规定的Ⅰ级精度。该设计方法可用于不同型号的C型折弯机。

In order to solve the problem of inconsistent angle in the length direction of the bending pieces due to structural deformation in the loading process of C--type bending machine, Timoshenko beam theory was applied to establish a analytical model of crowning,and the influence of some factors such as shape, size and inertia on the accuracy of bending were considered. Then, the deformation mechanism of bender slider and table stand plate was deduced,and general laws of deformation as fol- lows were obtained. It is concluded that the superimposed deformation curve of the slider and table stand plate can be expressed by a quartic equation, and the deflection of the fixed point is in proportion to the load. Based on the analysis of commonly used deflection compensation methods,a wedge--type crowning compensation method was proposed. For one style of bending machines, the results of theo- retical analysis and wedge compensation method were utilized together to design a kind of deflection compensation device. Through the trial comparison, it is found that the angle deviation of the bent piece was controlled in the range of ±25′ by using this new device and exceeded I grade accuracy provided in the China national standard, while the deviation is ±1° without compensation. This design method can be used commonly to different types of C-type bending machines.