0
Research Papers: Hydrodynamic Lubrication

Hydrodynamic Performance Produced by Nanotexturing in Submicrometer Clearance With Surface Roughness

[+] Author and Article Information
Tomoko Hirayama

Department of Mechanical Engineering,
Doshisha University,
1-3 Miyakodani, Tatara,
Kyotanabe, Kyoto 610-0394, Japan
e-mail: thirayam@mail.doshisha.ac.jp
PRESTO,
Japan Science and Technology Agency,
4-1-8 Honcho,
Kawaguchi, Saitama 332-0012, Japan

Heinosuke Shiotani, Kazuki Yamada, Naoki Yamashita

Graduate School of Science and Engineering,
Doshisha University,
1-3 Miyakodani, Tatara,
Kyotanabe, Kyoto 610-0394, Japan

Takashi Matsuoka

Department of Mechanical Engineering,
Doshisha University,
1-3 Miyakodani, Tatara,
Kyotanabe, Kyoto 610-0394, Japan

Hiroshi Sawada, Kosuke Kawahara

Canon Machinery Inc.,
85 Minamiyamada-cho,
Kusatsu, Shiga 525-8511, Japan

Contributed by the Tribology Division of ASME for publication in the JOURNAL OF TRIBOLOGY. Manuscript received May 2, 2014; final manuscript received September 24, 2014; published online October 23, 2014. Assoc. Editor: Min Zou.

J. Tribol 137(1), 011704 (Oct 23, 2014) (8 pages) Paper No: TRIB-14-1101; doi: 10.1115/1.4028736 History: Received May 02, 2014; Revised September 24, 2014

Surface texturing is a promising way to expand the hydrodynamic lubrication regime and thereby modify the tribological properties of sliding surfaces. Spiral-groove textures in particular have attracted much attention over the past several decades because they produce a thicker lubrication film in the gap. However, no research has been reported on the effect of periodic texturing with a several 100 nm depth on hydrodynamic performance in submicrometer clearance with surface roughness. The purpose of the study reported here was to investigate the effect of such nanotexturing on hydrodynamic performance. This was done by conducting ring-on-disk friction tests, focusing on the existence of surface roughness in the narrow clearance. The samples were rings with various degrees of surface roughness and disks with spiral-groove textures produced by femtosecond laser processing. The friction coefficients experimentally obtained were plotted as a Stribeck curve and compared with a theoretical one calculated using a Reynolds equation formulated from two physical models, the Patir–Cheng average flow model and a sinusoidal wave model. The results showed that surface roughness did not affect the friction coefficient in the hydrodynamic lubrication regime. However, the hydrodynamic lubrication regime gradually shrank with an increase in surface roughness, and mild transitions to the mixed lubrication regime were observed at higher rotational speeds. The minimum clearances reached at the transition speed were almost the same, about 200–300 nm, for all experiments regardless of surface roughness.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Theoretical load capacity and coefficient of friction of spiral-groove bearing pad with different groove depths against change in clearance

Grahic Jump Location
Fig. 2

Ring-on-disk friction tester

Grahic Jump Location
Fig. 3

Ring specimen and optical microscope images of surfaces with various degrees of roughness: (a) 0.005, (b) 0.05, (c) 0.1, and (d) 0.15 Ra

Grahic Jump Location
Fig. 4

Disk specimen with spiral-groove nanotexturing

Grahic Jump Location
Fig. 5

Coefficient of friction for oil viscosity of 27.0 cP and applied load of 53.9 N: (a) raw data for textured and flat disks with A1 ring specimen, (b) raw data for textured disk with different ring specimens, and (c) data plotted as Stribeck curve from Fig. 5(b)

Grahic Jump Location
Fig. 6

Experimentally obtained Stribeck curves along with theoretical curves for different rings with various degrees of surface roughness: (a) A1, (b) B1, (c) C1, and (d) D1 specimens

Grahic Jump Location
Fig. 7

Stribeck curves for A2, B2, C2, and D2 ring specimens with oil viscosity of 27.0 cP and applied load of 70.6 N

Grahic Jump Location
Fig. 8

Stribeck curves with Hersey number on horizontal axis for comparing results for applied loads of 53.9 and 70.6 N

Grahic Jump Location
Fig. 9

Stribeck curves for A3 and C3 ring specimens with oil viscosity of 42.8 cP and applied load of 53.9 N

Grahic Jump Location
Fig. 10

Stribeck curves with Hersey number on horizontal axis for comparing results for oil viscosities of 27.0 and 42.8 cP

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In