移动切削力激励下的大型丝杠硬旋铣系统动态响应分析

Dynamic Response Analysis of Large-scale Screw Whirling System Subjected to a Moving Load

以六米大型丝杠硬旋铣系统为研究对象,运用全局假设模态法,建立了丝杠工件在断续周期性移动切削力激励和卡盘、浮动支撑、抱紧装置,尾架约束下的动力学模型,分析了丝杠工件在移动切削力激励下切削全程的动态响应特性,以及抱紧及支撑装置对丝杠工件切削全程中各切削点动态响应幅值均值的影响。结果表明:抱紧装置的移动对丝杠工件的动态响应影响较小,而浮动支撑的升降显著影响工件系统的动态特性;丝杠工件的动态响应不是随抱紧刚度的增大而单调减小,选择合理的抱紧刚度可以减小工件的装夹变形,同时工件的动态特性也能满足加工精度的要求。

This paper takes the large-scale screw whirling system as the research object, to analyze the dynamic response under a moving load. The moving load is interrupted and periodical, motivated by the cutting force in the whirling process. The screw workpiece is supported by the chuck, floating rests, hold devices and tailstock. The effect of the hold devices and floating rests on the dynamic characteristics of the workpiece was also analyzed. The numerical results show that the floating rests have a more signifi- cant influence on the dynamic characteristic of the workpiece system than the hold devices. The dynamic response does not decrease monotonously with the increase of the stiffness of hold devices. The reasona-ble rigidity can not only meet the screw precision requirement, but also decrease the workpiece clamping deformation.