工作機械構造の基本設計段階における静剛性と振動特性の評価パラメータの解析

Abstract

In order to improve and optimize structural design at the fundamental design decision stage of machine tools, new parameters for evaluating the static rigidity and dynamic characteristics are proposed which can deal with the various arrangements of cutting and the various types of machining operations. The parameters are the resultant static compliance which sums up static compliances in three coordinate directions of any orthogonal coordinate system at the cutting point, and the ratio of the modal flexibility in the principal modal direction of the natural mode to the resultant statc compliance. The evaluation based on both the parameters doesn't depend on the directional orientations of the cutting point (such as the cutting force direction and the direction normal to the cut surface). The static rigidity at the cutting point is macroscopically evaluated by the resultant static compliance. The stability for the regenerative chatter is roughly judged using the ratio of the modal flexibility in the principal modal direction to the resultant static compliance. This paper describes the theoretical analysis of the proposed parameters, and the method for evaluating and improving structural design is described and demonstrated by simulated results on a simplified machine tool model.