Controllable preload spindle with a piezoelectric actuator for machine tools

The increased demand for high-speed, high-precision, stable, and long-life machine tools has made high-precision spindles an important topic of research. The key component of the machine tool spindle that supports the shaft is the ball bearing, whose characteristics are closely related to the spindle preload. In this study, a spindle preload control mechanism is designed using a piezoelectric actuator and a beveled spacer ring. Mechanical effects of the spindle preload are analyzed and controlled, and an experimental full-sized model is fabricated and tested. Results show that increased preload reduces vibration amplitude and raises the bearing temperature. All the measured mechanical effects are positively correlated with the controlled spindle preload.