Herringbone-grooved bearing with non-uniform grooves for high-speed spindle

A hydrodynamic bearing with non-uniform herringbone grooves has been developed for use with high-speed motor spindles. The grooves gradually become narrower, shallower and less straight (curved) towards the herringbone centre along axial direction, resulting in an increased pumping effect of the spiral grooves. The optimum dimensions of the grooves for increasing the critical bearing number were clarified theoretically, and bearings with non-uniform herringbone grooves were found to increase the critical bearing number against the half-frequency whirl up to about 50% in comparison to bearings with uniform herringbone grooves. Experiments to investigate the suitability of the proposed bearing for high-speed spindles showed that the maximum rotational speed of a spindle with this bearing was about 20% higher, close to the theoretically predicted 23%, and thus proved that application of this bearing should enable spindles to achieve faster stable rotation as theoretically expected. Copyright © 2010 John Wiley & Sons, Ltd.