高速精密微主轴对刀具夹持机构的动平衡性能及动力学特性等方面提出很高的要求。建立一种基于形状记忆合金(Shapememoryalloy,SMA)的一体式微夹头的结构方案,设计分析具体的应用实例,并仿真研究离心力对夹头夹持性能的影响;研究采用TiNi合金(Ti49.6%,Ni50.4%)加工的SMA环的最大双程形状记忆效应所对应的热.机械训练工艺。试制出微夹头样品,测试其安装操作和夹持力等性能。结果表明微夹头在-5℃即可实现夹持件的安装与拆卸,在室温(15℃、时即可夹紧,夹紧力约为8.5N:当加热温度提高到65℃时,夹紧力可以达到41N。该微夹头不仅结构简单,动平衡性能好,而且未引入新的安装误差,操作简单,大小调整方便,适合于超高速超精密微主轴及其他高速精密微小型传动机构。
The high speed precision micro-spindle requires the tool chuck with very good balance performance and dynamic characteristic. A structural concept of the monolithic micro-tool chuck using shape memory alloy (SMA) is established. The design analysis of an application example is carried out. The influence of the centrifugal force on the clamping performance is studied through simulation. The manufacturing process of the SMA ring using TiNi (Ti49.6%, Ni50.4%) alloy for the maximum two shape memory effect is studied. The prototype is manufactured and its performance including installing operation and clamping force are tested. The results show the clamped part can be inserted or removed at a temperature of-5 ℃, and clamped at room temperature (15 ℃). The corresponding clamping force is about 8.5 N. when the heating temperature is increased to 65℃, the clamping force increases to 41 N. The monolithic micro-tool chuck has not only simple configuration and good balance performance, but also no adding installation error, convenient operation, easy size adjustment, so it is feasible for application in the ultra-high speed and ultra-high precision micro-spindle and other high speed precision miniature transmission device.