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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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TEM images of the cross section of tribo-layer (a) whole view of cross section showing the thickness of about 400 nm of tribo-layer, (b) magnified view of tribo-layer showing the dark spots of In in nano-meter scale.71)
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f37-287: TEM images of the cross section of tribo-layer (a) whole view of cross section showing the thickness of about 400 nm of tribo-layer, (b) magnified view of tribo-layer showing the dark spots of In in nano-meter scale.71)

Mentions: The TEM image of the cross section of tribo-layer in Fig. 36 (a1) is shown in Figs. 37(a) and (b), where (a) shows the whole cross sectional view of a tribo-layer of about 400 nm thickness and (b) shows its partial magnified view. The dark spots in (b) has crystalline structure as shown by the TEM image in Fig. 38(a) and the matrix of relatively light color part has amorphous structure as shown by the diffraction pattern in Fig. 38(b).


Studies on tribology.

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

TEM images of the cross section of tribo-layer (a) whole view of cross section showing the thickness of about 400 nm of tribo-layer, (b) magnified view of tribo-layer showing the dark spots of In in nano-meter scale.71)
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f37-287: TEM images of the cross section of tribo-layer (a) whole view of cross section showing the thickness of about 400 nm of tribo-layer, (b) magnified view of tribo-layer showing the dark spots of In in nano-meter scale.71)
Mentions: The TEM image of the cross section of tribo-layer in Fig. 36 (a1) is shown in Figs. 37(a) and (b), where (a) shows the whole cross sectional view of a tribo-layer of about 400 nm thickness and (b) shows its partial magnified view. The dark spots in (b) has crystalline structure as shown by the TEM image in Fig. 38(a) and the matrix of relatively light color part has amorphous structure as shown by the diffraction pattern in Fig. 38(b).

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