Static Characteristics of Water-Lubricated Hydrodynamic Spiral-Groove Journal and Thrust Bearings for Motorized Spindle

Oil-lubricated hydrodynamic bearing is a typical support for motorized spindle. However, a motorized spindle supported by the oil-lubricated hydrodynamic bearing has disadvantages regarding high-temperature rise and low rotational speed. To overcome this problem, this technical brief proposes novel water-lubricated hydrodynamic spiral groove bearings for the motorized spindle. A rotor-bearing static model for the motorized spindle was established considering the external loads and the tilting effect of bearings. An experimental prototype for the motorized spindle was developed, and the theoretical calculation and experimental research on the bearing static characteristics were carried out. The result shows that the water-lubricated hydrodynamic spiral groove bearings have significant advantages in terms of low-temperature rise, good high-speed performance, and moderate spindle stiffness, together with the inherent low manufacture cost and high rotation accuracy of the bearings, and the proposed bearings can be a potential alternative to the fluid bearing for the high-speed motorized spindle.