Theoretical and experimental approach to ball bearing frictional characteristics compared with cryogenic friction model and dry friction model

Title
Theoretical and experimental approach to ball bearing frictional characteristics compared with cryogenic friction model and dry friction model
Authors
이전국이용복곽원일
Keywords
Cryogenic fluid; Solid lubrication; Friction model; Traction coefficient; Hydrodynamic effect
Issue Date
2019-06
Publisher
Mechanical systems and signal processing
Citation
VOL 124-438
Abstract
In previous studies on cryogenic ball bearings, a friction model of solid lubrication characteristics was employed with the assumption that the low dynamic viscosity of cryogenic fluids is negligible. A traction curve was then created using this dry friction model, with curve fitting being performed using a traction coefficient derived from the results of a ball-on-disk experiment with corresponding solid lubricant. However, the behavior prediction had many limitations, because the fluid characteristics in the cryogenic environment and the friction characteristics of the bearing components were not reflected. This study attempts to improve the reliability of cryogenic ball bearing dynamic analysis by proposing a hydrodynamic friction model considering the hydrodynamic effect of cryogenic fluids. A ball-on-disk experiment is conducted by simulating (1) ball-cage friction, (2) ball-inner/outer race friction, and (3) cage-inner/outer race friction characteristics. Hence, it is found that uncertainty factors causing traction coefficient fluctuation exist in certain device sections, reflecting the effect on the wear surface of friction and the hydrodynamic effect of the shear stress of the cryogenic fluid (liquid nitrogen). A dynamic experiment and cryogenic ball bearing analysis using the model considering the hydrodynamic effect are conducted and compared. From the ball bearing dynamic behavior analysis, the hydrodynamic friction model is found to predict a bearing friction coefficient that is closer to the actual value than the dry friction model. When the proposed model is applied to bearing dynamic behavior, it is possible to predict the cryogenic-bearing friction coefficient with 50% higher accuracy than the existing method.
URI
http://pubs.kist.re.kr/handle/201004/69078
ISSN
0888-3270
Appears in Collections:
KIST Publication > Article
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE