Laser Doppler Vibrometer (LDV) Measurement of Ultrasonic Vibration Antifriction of a Ball Screw Pair Based on the Second-order Torsional Modal
Y. Chen, Y-M. Xie, Y-D. Zhao, C. Zhang and Q. He
The mass produced single nut ball screw pair taken as the research object for an antifriction method by using ultrasonic vibration to reduce the friction of ball screw pair is proposed. A piezoelectric (PZT) vibrator is connected on the nut to form the antifriction vibrator. By exciting the PZT ceramics in the PZT vibrator, the vibration modal of the antifriction vibrator is excited. The ultrasonic vibration velocity is generated between the ball raceway contact pair and the ultrasonic vibration antifriction is realized. The modal analysis of the antifriction vibrator was carried out by using the finite element method (FEM). The second-order torsional vibration modal was determined as the working modal and the size of the main structure for this modal was determined. The sample was manufactured, and the resonance frequency and vibration modal of the antifriction vibrator were measured by an ingenious method with laser Doppler vibrometer (LDV). The test results show that the second-order torsional vibration of the antifriction vibrator can be excited when the frequency is 31 kHz. This is consistent with the simulation results. The ultrasonic vibration antifriction system of ball screw pair was established. The unloaded antifriction performance experiment of the antifriction system was carried out. The average friction reduction percentage can reach 7.87%. The result shows that the antifriction vibrator can effectively reduce the friction of ball screw pair. Since there is no need to change the structure of the mass-produced ball screw pair and lower power consumption, the method proposed in this paper has a certain commercial prospect.
Keywords: Laser Doppler vibrometer (LDV), ball screw pair, piezoelectric (PZT), ultrasonic antifriction, torsional vibration, finite element method (FEM), modal analysis