离心力影响下的高速主轴？怖？杆系统动态特性
Dynamic Characteristics of Rotor？？Draw Bar System in High？？Speed Spindle under Influence of Centrifugal Force

为进一步明确离心力对主轴系统动态特性的影响,以高速主轴？怖？杆系统为对象,建立了刀柄的接触力学模型,考虑了碟簧在离心力作用下产生的径向伸展,并计算了该变形导致的拉力随主轴转速的变化关系。在此基础上,讨论了刀柄接触应力随初始拉力、动态夹紧力的变化规律,揭示了上述变化对主轴系统自然频率的影响。结果表明:碟簧的径向伸展会造成刀杆拉力的减小,但减小的程度受碟簧规格和初始拉力的影响,对于拉紧力较小的超高速主轴,该影响较为显著,而对于拉紧力较大的普通主轴,该影响可以忽略;静、动态夹紧力的夹紧效率随摩擦因数的增大而降低;动态夹紧力可显著提升接触应力,但过高的夹紧力反而会加大接触间隙,降低结合部阻尼,导致主轴系统自然频率的减小。
In order to further clarify the influence of centrifugal force on the dynamic characteristics of high？？speed spindle system, a contact model of toolholder is established by taking the rotor？？draw bar system as the research target, and considering the radial extension of disc spring under centrifugal force. The relationship between the tension caused by deformation of disc spring and the rotation speed is investigated. On this basis, the changing rule of the contact stress of toolholder with the initial tension force and the dynamic clamping force is studied, hence the effect of these changes on the natural frequency of the rotor system is revealed. The result shows that the radial extension of disc spring will cause a reduction of the tension of draw bar, and the decrease of tension is related to the geometry size and initial tension force. For the spindle with small tension force, the influence is remarkable; while it can be neglected for the spindle with large tension force. The clamping efficiency under initial force or dynamic clamping force decreases with the increase in rotating speed. The contact stress can be raised by increasing the dynamic clamping force. However, an excessive clamping force will increase the contact clearance and reduce the damping at joint interface, and finally decrease the natural frequency of the rotor system