数控机床HSK刀柄和主轴在高速旋转下的连接性能分析

摘要

刀柄与主轴连接性能对数控机床的加工精度以及工作安全性影响显著。针对HSK刀柄在高速旋转过程中发生刀柄和主轴连接失效这一主要失效形式,应用弹性力学理论建立了任一转速下刀柄与主轴连接锥面的接触应力模型,且有限元分析结果与该理论模型有较好的一致性。在此基础上,综合考虑夹紧力以及刀柄、主轴配合过盈量的影响,建立了基于HSK刀柄与主轴连接的临界转速计算模型以及连接可靠性模型。根据临界转速模型可以从理论上计算出一定过盈量和夹紧力下的临界转速,分析夹紧力和过盈量对临界转速的影响。根据连接可靠性模型可以求解任一转速下刀柄和主轴连接的可靠度,并得到可靠度随转速的变化规律。这两个模型的建立对防止HSK刀柄、主轴连接的失效,保证高速切削加工的精度以及工作的安全性有重要意义,同时也为正确使用HSK刀柄以及刀柄尺寸结构进一步优化和可靠性设计提供了理论基础。%The connection performance of HSK toolholder and spindle has great influences on machining accuracy and security of CNC machine tools. In viewing this, given the crucial fact that the HSK toolholder~spindle connection may encounter failure at high rotational speed, a contract stress model on the HSK toolholder/spindle junction surface was built at any rotational speeds. And the re- sults of finite element analysis have good uniformity with this model. By using this stress model, con- sidering the influence of clamping force and magnitude of interference, the computational model of critical rotational speed based on the HSK toolholder and spindle connection and the interface reliabili- ty were established. With the computational model of critical rotational speed, an accurate calculation of the critical rotational speed was attainable. And the influence of clamping force and magnitude of interference on critical rotational speed was also discussed. The interface reliability at any rotational speed can be accurately calculated and the relationship between rotational speed and interface reliabili- ty was found according to the interface reliability mode. The establishment of the two modes is mean- ingful to prevent the HSK toolholder/spindle interface failure and guarantee machining accuracy and security of CNC machine tools. Meanwhile, it also provides a theoretical foundation for the reasonable utilization, optimization of parameters and reliability design of the HSK tool--holder.