数控机床进给系统摩擦自激振动研究

Study on the frictional self-excited vibrating of the feed system in NC machining tool

建立了数控机床进给系统的动力学模型,运用描述函数法对系统低速运动时工作台出现摩擦自激振动的原因进行了分析.结果表明:负阻尼区的存在是产生摩擦自激振动的根本原因.通过增加正阻尼、增大系统阻尼系数等措施可以消除负阻尼区;改善系统运动部件的工作条件也是抑制摩擦自激的有效措施.

A dynamic model for the feed system in NC machining tool is established.Reasons for the frictional self-excited vibrating caused by low feed speed of system are analyzed by using describing function method.The results show that the existence of a negative damped area is the fundamental reason for producing frictional self-excited vibrating.In order to eliminate the negative damped area a positive damping should be added or damping coefficient of the system should be enlarged.In addition,improving work conditions of motive parts is the effective measure to control frictional self-excited vibrating.