A Study on Grease Leakage from Rolling Bearings

Main Article Content

Naofumi Hiraoka

Abstract

The leakage of grease from shielded rolling bearings is usually caused by grease being pushed out by ball or cage motion, centrifugal force, or grease flow due to high temperature. However, we have discovered another mechanism that causes significant leakage: slippage of the grease lump caused by adhesion forces to the shield plate and inner race which typically occurs in case of slippery grease on the surface.

Article Details

Section
Research Article

References

W. C. Moratz, “Sealed Bearings-Environmental and Economical Advantages,” Mech. Work. Steel Process, vol. 37, pp. 779-783, 1999.

Japanese Society of Tribologists, Ed., Basic and application of lubricating grease,. Tokyo,Yokendo, 2007.

P. M. Cann, M. N. Webster, J. P. Doner, V. Wikstrom, and P. Lugt, “Grease degradation in R0F bearing tests,” Tribology Transactions, vol. 50, no. 2, pp. 187-197, 2007.

P. M. Lugt, “A review on grease lubrication in rolling bearings,” Tribology and Lubrication Technology, vol. 66, no. 7, pp. 44-56, 2010.

H. Ito, M. Tomaru, and T. Suzuki, “Physical and chemical aspects of grease deterioration in sealed ball bearings,” Lubr. Eng., vol. 44, no. 10, pp. 872-879, 1988.

Research committee on lubricating greases for the 18th term, “Joint research report on lubricating greases (1),” Junkatsu vol. 21, pp. 463-8, 1975.

Research committee on lubricating greases for the 19th, 20th and 21th terms, “Joint research report on lubricating greases (3),” Junkatsu, vol. 22, pp. 641-6, 1977.

Research committee on lubricating greases for prelubricated bearings “Joint research report on lubricating greases for prelubricated bearings,” Junkatsu, vol. 24, pp. 580-4, 1979.

Research committee on synthetic greases for prelubricated bearings, “Effect of base oils on functional life of greases,” Junkatsu, vol. 27, pp. 167-72, 1982.

R. J. Pecora Jr., E. W. Vest, and M. J. Diodato, “Leakage resistance of wheel bearing greases in disc brake applications,” N L G I Spokesman vol. 38, no. 11, pp. 388-391, 1975.

P. R. McCarthy and W. W. Bailey, “Laboratory evaluation of automotive wheel bearing and ball joint greases,” N L G I Spokesman, vol. 39, no. 5, pp. 158-166, 1975.

N. Sato and T. Sakaguchi, “Improvement of grease leakage prevention for ball bearings due to geometrical change of ribbon cages,” NTN Technical Review, vol. 78, pp. 91-97, 2010.

H. Koizumi, Rolling bearing, Japanese Patent, P2000-87984A

N. Hiraoka, “On grease leakage from rolling bearings,” Tribology International, vol. 50, pp.45-50, 2012.

N. Hiraoka and H. Sasaki, “A study on a mechanism of grease leakage from rolling bearings,” Journal of the Japanese Society of Tribologists, vol. 55, pp. 120-127, 2010.