0
Research Papers

Reducing Friction in Tilting-Pad Bearings by the Use of Enclosed Recesses

[+] Author and Article Information
Niels Heinrichson

Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmarknhe@mek.dtu.dk

Ilmar Ferreira Santos

Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmarkifs@mek.dtu.dk

J. Tribol 130(1), 011009 (Dec 26, 2007) (9 pages) doi:10.1115/1.2805428 History: Received September 12, 2006; Revised May 20, 2007; Published December 26, 2007

A three-dimensional thermoelastohydrodynamic model is applied to the analysis of tilting-pad bearings with spherical pivots and equipped with deep recesses in the high-pressure regions. A potential for a 10–20% reduction in the friction loss compared to conventional plain bearing pads is documented. Design suggestions minimizing the power loss are given for various length-to-width ratios. The tilting angle in the sliding direction is more sensitive to correct positioning of the pivot point than conventional bearing pads. Improving the performance by equipping a tilting-pad bearing with a deep recess therefore requires accurate analysis and design of the bearing. Similarly, a high sensitivity perpendicular to the sliding direction suggests that this method of reducing friction is more feasible when using line pivots or spring beds than when using spherical pivots for controlling the tilting angle.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Flow chart for the program.

Grahic Jump Location
Figure 2

Left: The bearing pad used in Ref. 1 for the one-dimensional analysis. Right: The bearing pad used for the two-dimensional analysis. The recess is 20μm deep.

Grahic Jump Location
Figure 3

One-dimensional analysis of linear bearing operating at a speed of 30m∕s, a load of 1.0MN, and a minimum film thickness of 75μm. The generated friction loss and the bearing width are illustrated for various film thickness convergence ratios hle∕hte. (a) Illustration of the position of the recess. (b) Generated friction loss. (c) Bearing width.

Grahic Jump Location
Figure 4

Drawing of a rectangular pad with a recess. Lpad and Wpad define the pad length and width. Lpivot denotes the distance of the spherical pivot from the leading edge of the pad. Lrecess and Wrecess denote the minor and the major axis of the elliptical recess and Lend defines the position of the recess relative to the trailing edge.

Grahic Jump Location
Figure 5

(a) and (b) state design parameters defining the recess geometry and the pivot position for rectangular pads. The values are chosen to minimize the friction loss. In (c), two sets of curves are shown. The curves marked with (I) represent the percentage increase in the pad surface area with a recess in the pad surface relative to the area of a pad without a recess. The curves marked with (II) represent the area of the recess relative to the area of a pad without a recess. (d) shows values of thermal bending, (e) states the friction loss, and (f) the reduction in friction for recessed bearing pads relative to nonrecessed pads.

Grahic Jump Location
Figure 6

Illustration of the sensitivity of the friction loss to the pivot position and recess length (a) Friction loss as a function of pivot position (b) The influence of recess length on the friction loss (isothermal analysis)

Grahic Jump Location
Figure 7

The sector shaped bearing pad considered. The recess size and position are defined by Eq. 1.

Grahic Jump Location
Figure 8

(a) and (b) state the radial and circumferential pivot position for sector shaped pads with and without recesses. The values are chosen to minimize the friction loss and are stated for various length-to-width ratios. The pad length is defined as Lpad=θpadrmean. (c) states the friction loss and (d) the reduction in friction for recessed bearing pads relative to nonrecessed pads.

Grahic Jump Location
Figure 9

Left: Minimum oil film thickness as a function of the position of the pivot point for the eight-pad bearing with a length-to-width ratio of 0.9. Middle: Isothermal analysis showing the influence of recess size on the minimum oil film thickness. Right: The minimum obtainable friction loss for the recess size shown in the middle figure. (a) Dependency of the radial positioning of the pivot point and of the radial size of the recess. (b) Dependency of the circumferential positioning of the pivot point and of the circumferential size of the recess.

Grahic Jump Location
Figure 10

Results from the TEHD analysis of the eight-pad bearing with a recess

Grahic Jump Location
Figure 11

The influence of recess depth on the friction loss. Full lines indicate results obtained with the laminar model. Dashed lines indicate estimates of the influence of turbulent recess flow. (a) The friction loss in the recess area. (b) The friction loss in the bearing. (c) The friction reduction relative to an optimal nonrecessed bearing.

Grahic Jump Location
Figure 12

Behavior of bearings with various recess sizes subject to hybrid lubrication at different velocities. The oil film thicknesses at the four corned points are presented. The line legend for all four figures is stated in (c). (a) Cylindrical pocket at pivot point. (b) Lrecess=0.400∙Lpad (c) Lrecess=0.565∙Lpad (d) Lrecess=0.700∙Lpad

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