超声珩齿弯曲振动变幅器的位移特性

Displacement Characteristics of Transverse Vibratory Disc Transformer in Ultrasonic Gear Honing

超声振动可以有效地减小珩磨力,超声空化现象与切削液的共同作用可以对珩磨轮实现实时动态清洗,从而减小珩磨轮堵塞,提高加工效率,因此超声和珩齿的复合加工是一种应用前景良好的齿轮精加工方法。超声珩齿的加工对象——齿轮,直径大,厚度小,是一类特殊负载,且对振动系统的加工频率影响大,所以在超声振动系统设计时,必须将变幅杆和齿轮全面考虑建立动力学方程。为此,将齿轮简化为圆盘,加工过程中齿轮作只有圆节线的弯曲振动,采用圆锥型变幅杆,推导变幅杆和圆盘组成的变幅器的频率方程,并利用它设计了变幅器,对变幅器动力学参数的数值计算、有限元分析及试验测量结果一致。通过计算变幅器中变幅杆和圆盘各自独立的谐振频率,发现与变幅器的谐振频率误差较大,说明变幅器设计时必须同时考虑变幅杆和圆盘的相互作用,否则设计的变幅器谐振频率误差过大。

Ultrasonic vibration can reduce honing forces efficiently, and ultrasonic cavitation and cutting fluids can play an important role in realizing real-time dynamical washing in order to decrease the blockage of honing wheel and increase the honing efficiency, so the gear honing combined with ultrasonic machining is a precision machining method of gears with good prospect of application. The gear with large diameter and small thickness, which is the object machined by ultrasonic honing, is a special load that influences the machining frequency of vibration system greatly, hence the horn and gear must be considered simultanecusly to establish the dynamic equations when the ultrasonic vibration system is designed. Therefore gear is simplified as a disc and is limited to vibrate transversely with nodal circles in the process of machining, and cone-shaped hom is adopted. The frequency equations of transformer that consists of the disc and horn are derived. Based on the equations, the amplifier is designed and its dynamic parameters are calculated numerically and analyzed by finite element method. The results are consistent with experimental measurement. Through calculating resonant frequencies of the horn and disc independently, the results show that the frequencies are not equal to one of transformer and the error is heavier, which means that the interaction between the horn and gear must be considered at same time when the transformer is designed, otherwise the large error will be caused.