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REVIEW ARTICLES

J. of Lubrication Tech. 1973;95(1):1-32. doi:10.1115/1.3451731.

The volume of lubrication literature continued to expand, reflecting increased experimental and theoretical attention being focused upon this discipline. The following eleven categories of lubrication technology are summarized by authorities in each particular field: Developments in Lubrication (including synthetics and greases); Metal-working Lubricants; Plain Bearings; Frictional Behavior of Materials; Wear; Solid Lubrication; Rolling Bearings; Incompressible and Compressible Fluid Film Lubrication and Bearings; Static and Dynamic Seals; Gears and Splines. Over 600 reference publications are included in the review.

Commentary by Dr. Valentin Fuster

RESEARCH PAPERS

J. of Lubrication Tech. 1973;95(1):33-41. doi:10.1115/1.3451732.

Pneumatic phase shifting is studied as a means for self-excited whirl stabilizations in externally pressurized journal gas-bearings. The pneumatic phase shifting stabilizer is composed of several pairs of pneumatic capacitors and restrictors. The stabilizer in this study utilizes negative capacitor pressure instead of positive capacitor pressure as in the case of the Sixsmith design.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):42-51. doi:10.1115/1.3451733.

A static and dynamic analysis is carried out for spherical hydrostatic bearings under conditions of incompressible flow. The usual static theory is shown to need the addition of quadratic loss effects in order to agree with experiments. Computer models of static and dynamic behavior agree well with experimental data. Procedures for estimating stiffness and damping are presented taking the extra quadratic losses into account. Comparison with circular recess bearings shows that spherical bearings appear capable of higher damping ratio for the same size bearing.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):52-58. doi:10.1115/1.3451734.

A generalized approach based on a model of the Boltzmann equation is suggested for predicting velocity profiles and gas flow rates through trapezoidal microgaps. Sample results are given for selected trapezoidal, rectangular, square, and circular cross section passages for Knudsen numbers ranging from 0.1 to about 10. Comparison of predicted flow rates for rectangular passages with available empirical data seems to indicate that where passage size is characterized by a single dimension, a simple across-channel measurement is inappropriate. While relative velocity profiles are independent of this value, flow rates are not. Accuracy of predictions may be enhanced by matching with analytical or empirical results for similar geometries of larger size. A flow rate from the low Knudsen number end of the transition regime is matched with one from the overlapping region of the slip-flow regime and an arbitrary adjustment is made in the characterization of passage size. This adjustment can then be incorporated into the results throughout the transition regime.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):59-64. doi:10.1115/1.3451735.

An analysis is proposed for estimating the average interface temperature rise during sliding of two surfaces. The basic model includes surface topography statistics, frictional conditions, the effective surface hardness, and thermal parameters. In 75 percent of the material pairs studied, the analysis gives fairly good results. It appears applicable to either dry or lubricated surfaces.

Topics: Temperature
Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):65-70. doi:10.1115/1.3451736.

An experimental study has been carried out of wear and energy dissipation of contacts vibrated at high frequencies. The amplitude, number of cycles, and degree of lubrication were varied. In addition, an analysis was carried out of quantitative fretting wear results described in the literature. The results suggest that the material loss resembles that produced by unidirectional adhesive wear much more closely than it does that produced by other types of wear, and that in fact the amount of wear may be computed by the use of Archard’s equation.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):71-75. doi:10.1115/1.3451739.

Thermoelastic instability of rubbing contact results from the interaction of thermal expansion, frictional heating, and conduction of heat away from the contact zone. These interactions are modified by wear, which is shown to damp the growth of disturbances in contact pressure from a nominal uniform value. In some cases the presence of wear is found to give rise to oscillatory behavior where portions of the rubbing surfaces alternately rise and drop in temperature. These effects are analyzed for the case of a two-dimensional scraper or blade moving normal to its edge, which presses against the surface of a stationary semi-infinite body. The roles of material properties and operating variables are delineated in terms of dimensionless parameters appropriate to the system.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):76-81. doi:10.1115/1.3451740.

A series-hybrid bearing assembly consisting of a conical hydrostatic fluid-film bearing and a ball bearing is described. Computer studies are used to predict friction torque and life characteristics of a 150-millimeter ball bearing. A conical hydrostatic fluid-film bearing is designed for minimum friction and maximum speed reduction of the ball-bearing component of the series-hybrid bearing. At a thrust load of 4000 lb and speeds corresponding to DN (bearing bore in millimeters times shaft speed in rpm) values of 3 and 4 million, ball-bearing speed may be reduced by 30 percent. This speed reduction corresponds to ball-bearing fatigue life improvement factors of 3.4 at 3 million DN and 5.9 at 4 million DN. An oil flow rate at 18.2 lb per min is required to maintain a fluid-film thickness of 0.001 in. in the hydrostatic bearing.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):82-93. doi:10.1115/1.3451741.

Recently performed analysis for herringbone thrust bearings has been incorporated into the theory of the viscous screw pump for Newtonian fluids. In addition, certain earlier corrections for sidewall and channel curvature effects have been simplified. The result is a single, refined formula for the prediction of the pressure-flow relation for these pumps.

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):94-100. doi:10.1115/1.3451742.

Self-acting helical-grooved journal bearings, lubricated by an incompressible Newtonian liquid and operating under laminar conditions, have under favorable conditions a negligible leakage due to the inward pumping action of the grooves. During concentric running, the axial position of the gas liquid interface created in the grooved section of the bearing does not vary in circumferential direction (local effects due to a finite number of grooves are not taken into account). During eccentric running, however, the width of the liquid region, i.e., the interface varies in circumferential direction due to pressure differences in the lubricant film. For a complete herringbone journal bearing the interaction between the shape of the interface and the pressure distribution has been studied both theoretically and experimentally.

Commentary by Dr. Valentin Fuster

DISCUSSIONS

Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):70. doi:10.1115/1.3451738.
FREE TO VIEW
Abstract
Topics: Mechanisms

TECHNICAL BRIEFS

J. of Lubrication Tech. 1973;95(1):102-104. doi:10.1115/1.3451728.
Abstract
Topics: Equations
Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):104-106. doi:10.1115/1.3451729.
Commentary by Dr. Valentin Fuster
J. of Lubrication Tech. 1973;95(1):106-108. doi:10.1115/1.3451730.
Abstract
Topics: Torque , Particle spin
Commentary by Dr. Valentin Fuster

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