ASLE transactions

Equations for flow rate, pressure, load, and stiffness of externally pressurized thrust and journal bearings are given for purely viscous, isothermal gas films with longitudinal or radial flow and no relative surface motion. Charts are presented by means of which the bearing characteristics can be evaluated in terms of the bearing parameter, the bearing configuration, and the ratio of supply to ambient pressure. Sample characteristics of thrust and journal bearings are established using the curves and experimental confirmation shown. A method of treating bearing films with two inlet-restricting orifices in series is described.

I. C. Tang

W. A. Gross

A S L E Transactions

Analysis and Design of Externally Pressurized Gas Bearings

外部加压气体轴承的分析与设计

High-pressure annular seal leakage and dynamic coefficients vary with eccentricity and misalignment. Recent seal leakage data with both concentric and fully eccentric alignments support the seal leakage model with surface roughness and eccentricity effects included. In this paper, the seal dynamic coefficient calculation has been generalized and allows direct calculation of the seal dynamic coefficients at any circumferential location. The generalized solution agrees with the results obtained by wing the calculated values of an earlier paper and performing a coordinate transformation. The analysis results coincide with the measured data in showing that the stiffness and damping matrices of seal coefficients are not skew symmetric, and the main diagonal seal coefficients are not equal. The measured direct stiffnesses were found higher than predicted by the concentric seal theory, but this may be explained by the presence of eccentricity in the test operating mode.

W. C. Chen

E. D. Jackson

A Generalized Theory for Eccentric and Misalignment Effects in High-Pressure Annular Seals

高压环形密封中偏心与不对中效应的广义理论

The effect of inlet starvation on the hydrodynamic lubrication of lightly loaded rigid nonconformal contacts in combined rolling and normal motion is determined through a numerical solution of the Reynolds equation for an isoviscous, incompressible lubricant. Starvation is effected by systematically reducing the fluid inlet level. The pressures are taken to be ambient at the inlet meniscus boundary and the Reynolds boundary condition is applied for film rupture in the exit region. Results are presented for the dynamic performance of the starved contacts in combined rolling and normal motion for both normal approach and separation. It has been found that during normal approach, the dynamic load ratio (i.e. ratio of dynamic to steady-state load capacity) increases considerably with increase in the inlet starvation. The reverse effect is observed during separation when the dynamic load ratio reduces significantly. The effect of starvation on the dynamic peak pressure ratio is relatively small. Further, it has been observed that with increasing starvation, film thickness effects become significant in the dynamic behavior of the nonconformal contacts. For significantly starved contacts, the dynamic load ratio increases with increase in film thickness during normal approach and a similar reduction is observed during separation. A similar effect is noted for the dynamic peak pressure ratio. Ninety-five cases were run to incorporate the effects of starvation and film thickness on the dynamic load ratio and the peak pressure ratio as obtained in an earlier investigation for fully flooded contacts.

M. K. Ghosh

B. J. Hamrock

D. E. Brewe

Starvation Effects on the Hydrodynamic Lubrication of Rigid Nonconformal Contacts in Combined Rolling and Normal Motion

饥饿对刚性非共形接触在滚动和法向运动中的流体动力润滑的影响

A simplified, semianalytical model has been developed to analyze the effect of centrifugal inertia in two-phase face seals. The model is based on the assumption of isothermal flow through the seal, but at an elevated temperature, and takes into account heat transfer and boiling. Using this model, seal performance curves are obtained with water as the working fluid. It is shown that the centrifugal inertia of the fluid reduces the load-carrying capacity dramatically at high speeds and that operational instability exists under certain conditions. While an all-liquid seal may be starved at speeds higher than a “critical” value, leakage always occurs under boiling conditions.

P. Basu

W. F. Hughes

R. M. Beeler

Centrifugal Inertia Effects in Two-Phase Face Seal Films

两相面密封膜中的离心惯性效应

The purpose of this work is to clarify the oscillatory performances of ball bearing for vacuum application. The friction properties of several solid-lubricant films were examined by using a reciprocating tribometer in a vacuum and in air. Ball bearings lubricated with the same solid-lubricant films were then tested under small-angle oscillatory conditions. Bearing lubricated with Ag + MoS2 show the lowest starting torque and surface damage. This result corresponds to sliding tests results. The damage profile of oscillatory bearings corresponds to the profile of the contact elliptic area. The rolling scars are mainly caused by the differential slip between balls and races.

Shojiro Miyake

Sadao Takahashi

Small-Angle Oscillatory Performance of Solid-Lubricant Film-Coated Ball Bearings for Vacuum Applications

真空应用中固体润滑膜涂层球轴承的小角度振荡性能

A model utilizing simple structural defect theory in molecular monolayers quantitatively accounts for the relationship between measured friction coefficients at monolayer coverage and additive properties such as enthalpy of fusion, chain length, chain symmetry, and solubility in hydrocarbon media. This model is an extension of a recent model of boundary lubrication for a simple two-component lubricant (i.e., base lubricant and one additive) relating friction coefficient to surface coverage. For a given polar end group, it is shown that the lateral cohesive interactions between the hydrocarbon chains in the monolayer play the major role in reducing friction and that the sum total of these interactions approximates the enthalpy of fusion. The coupling between friction coefficient at monolayer coverage and solubility directly follows from thermodynamics.

M. Beltzer

S. Jahanmir

Role of Dispersion Interactions Between Hydrocarbon Chains in Boundary Lubrication

碳氢链间色散作用在边界润滑中的作用

出版信息	出版商: Society of Tribologists and Lubrication Engineers，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 1958，原创研究文献占比: ，自引率:， Gold OA占比:

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Analysis and Design of Externally Pressurized Gas Bearings

A Generalized Theory for Eccentric and Misalignment Effects in High-Pressure Annular Seals

Starvation Effects on the Hydrodynamic Lubrication of Rigid Nonconformal Contacts in Combined Rolling and Normal Motion

Centrifugal Inertia Effects in Two-Phase Face Seal Films

Small-Angle Oscillatory Performance of Solid-Lubricant Film-Coated Ball Bearings for Vacuum Applications

A Generalized Theory for Eccentric and Misalignment Effects in High-Pressure Annular Seals

Starvation Effects on the Hydrodynamic Lubrication of Rigid Nonconformal Contacts in Combined Rolling and Normal Motion

Centrifugal Inertia Effects in Two-Phase Face Seal Films

Small-Angle Oscillatory Performance of Solid-Lubricant Film-Coated Ball Bearings for Vacuum Applications

Role of Dispersion Interactions Between Hydrocarbon Chains in Boundary Lubrication