Thermal behavior of an improved face-grinding spindle: water-lubricated hydrostatic thrust bearing decreases temperature rise and increases axial stiffness

Abstract

Axial thermal deformation and axial stiffness are the leading technical indicators affecting face-grinding spindle manufacturing accuracy. However, the face-grinding spindle supported by rolling bearings lubricated with grease has a disadvantage regarding temperature rise, axial stiffness, and rotational accuracy. To overcome this issue, this study proposes a novel face-grinding spindle supported by combined bearings, which include a water-lubricated hydrostatic thrust bearing and two rolling bearings with an oil-air lubrication system. The thermal model for the proposed face-grinding spindle is established, and the spindle thermal behavior is analyzed systematically. An experimental prototype of the face-grinding spindle is developed, and the temperature rise of the spindle is detected to verify the thermal model. The result shows that the temperature rise of the proposed spindle can be decreased by the use of the water-lubricated hydrostatic thrust bearing. A comparative study between the two types of spindles shows that the proposed face-grinding spindle with the combined support has the technical advantage of low-temperature rise, high axial stiffness, and high rotation accuracy.