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Studies on tribology.

Hori Y, Kato K - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2008)

Bottom Line: Oil whip is one of such vibrations due to oil film action of journal bearing.Some mechanisms of wear are introduced for better understanding of tribo-layer.In the last part of this paper, the mechanisms of generating static friction are shown for the cases of plastic contact and elastic contact, which is the base for understanding the mechanism of initiation of macroscopic sliding.

View Article: PubMed Central - PubMed

Affiliation: Kanazawa Institute of Technology, Tokyo, Japan.

ABSTRACT
In high speed rotating machines such as turbines and generators, vibrations of a rotating shaft often hinder the smooth operation of the machine or even cause failure. Oil whip is one of such vibrations due to oil film action of journal bearing. Its mechanism and preventive method is explained and proposed in this paper. Further theoretical and experimental analyses are made for considering heat generation and temperature rise in hydrodynamic lubrication. The usefulness of the lubrication theory based on the k-epsilon model is also shown for bearings with high eccentricity ratios. In the latter half of this paper, water lubrication, nitrogen gas lubrication and tribo-coated indium lubrication are shown as new promising methods, and their mechanisms are discussed and the importance of tribo-layer is explained. Some mechanisms of wear are introduced for better understanding of tribo-layer. In the last part of this paper, the mechanisms of generating static friction are shown for the cases of plastic contact and elastic contact, which is the base for understanding the mechanism of initiation of macroscopic sliding.

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The effect of contact area shape on static friction coefficient μs.85)μs = 0.85 at circle, μs = 0.49 at square, μs = 0.48 at annulus, μs = 0.32 at triangle.
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Related In: Results  -  Collection


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f53-287: The effect of contact area shape on static friction coefficient μs.85)μs = 0.85 at circle, μs = 0.49 at square, μs = 0.48 at annulus, μs = 0.32 at triangle.

Mentions: In Fig. 53, four kinds of shape of contact area of similar size are tested in the same way as in Fig. 52 to see the effect of contact shape on friction.


Studies on tribology.

Hori Y, Kato K - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2008)

The effect of contact area shape on static friction coefficient μs.85)μs = 0.85 at circle, μs = 0.49 at square, μs = 0.48 at annulus, μs = 0.32 at triangle.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3722018&req=5

f53-287: The effect of contact area shape on static friction coefficient μs.85)μs = 0.85 at circle, μs = 0.49 at square, μs = 0.48 at annulus, μs = 0.32 at triangle.
Mentions: In Fig. 53, four kinds of shape of contact area of similar size are tested in the same way as in Fig. 52 to see the effect of contact shape on friction.

Bottom Line: Oil whip is one of such vibrations due to oil film action of journal bearing.Some mechanisms of wear are introduced for better understanding of tribo-layer.In the last part of this paper, the mechanisms of generating static friction are shown for the cases of plastic contact and elastic contact, which is the base for understanding the mechanism of initiation of macroscopic sliding.

View Article: PubMed Central - PubMed

Affiliation: Kanazawa Institute of Technology, Tokyo, Japan.

ABSTRACT
In high speed rotating machines such as turbines and generators, vibrations of a rotating shaft often hinder the smooth operation of the machine or even cause failure. Oil whip is one of such vibrations due to oil film action of journal bearing. Its mechanism and preventive method is explained and proposed in this paper. Further theoretical and experimental analyses are made for considering heat generation and temperature rise in hydrodynamic lubrication. The usefulness of the lubrication theory based on the k-epsilon model is also shown for bearings with high eccentricity ratios. In the latter half of this paper, water lubrication, nitrogen gas lubrication and tribo-coated indium lubrication are shown as new promising methods, and their mechanisms are discussed and the importance of tribo-layer is explained. Some mechanisms of wear are introduced for better understanding of tribo-layer. In the last part of this paper, the mechanisms of generating static friction are shown for the cases of plastic contact and elastic contact, which is the base for understanding the mechanism of initiation of macroscopic sliding.

Show MeSH
Related in: MedlinePlus