Characteristics of Water-lubricated conical bearings with spiral grooves for high speed spindles
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In this paper, two types of water-lubricated hydrostatic conical bearings with spiral grooves for high- speed spindles are investigated. One has a rigid bearing surface and the other has a compliant one. In these bearings, pressurized water is first fed to the inside of the rotating shaft and then intro-duced into spiral grooves through feeding holes. Therefore, water pressure is increased due to the effect of the centrifugal force at the outlets of feeding holes by shaft rotation and, furthermore, water pressure is also increased by the viscous pump effect of spiral grooves. The static characteristics of these bearings are theoretically predicted and calculated results are compared with experimental re-sults. It was found that the compliant surface bearing had larger load capacity in a relatively large bearing clearance than the rigid surface bearing, and lower bearing power consumption in a small bearing clearance though the load capacity is reduced.
Fig.1 Geometrical configuration of Water-lubricated conical beraing with spiral grooves
Fig.2 Water flow inside of the shaft
Water pressure at the outlet of a feeding hole is increased
due to the centrifugal effect of shaft rotation
Fig.3 Water pressure in the bearing clearance