关键词: Timoshenko梁, 弹性变形, 挠度补偿, 楔块式装置

Abstract:

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 follows 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 theoretical 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.

Key words: Timoshenko beam, elastic deformation, crowning compensation, wedge type device