Squeeze-film bearing is studied to develop a low-friction suspension for the output-axis gimbal of a single-degree-of-freedom gyroscope. Included are a review of pertinent literature, the theory of squeeze-film lubrication, and design elements

Pan, C. H. T.

English

NASA Technical Reports Server

June 1968	 Brief 68-10180 
.-
	
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Squeeze-Film Gas Bearing Technology 
is
Squeeze-film lubrication is fundamentally derived 
from the same physical process which provides load-
carrying capacity to self-acting and externally pre-
surized gas (air) film bearings. In each case, pressure 
buildup within the boundaries of the bearing is created 
by viscous retardation of the gas flow. The three 
types of bearing, however, differ in the origin of flow. 
In a self-acting bearing, adherence to the sliding sur-
face causes ambient gas to enter the bearing gap. In an 
externally pressurized bearing, a high-pressure supply 
forces gas flow through the gap. In a squeeze-film gas 
bearing, high frequency transverse oscillations of one 
of the bearing surfaces provide the pumping action of 
ambient air. The oscillatory squeeze motion results in 
a time-averaged pressurization effect, primarily as a 
consequence of the compressibility of the gas film; the 
magnitude of this pressurization increases with the 
amplitude of oscillation relative to the average gap. 
The advantages of the squeeze-film bearing relative 
to the externally pressurized bearing include compact-
ness, simplicity of construction, and ease of regula-
tion. Its load-carrying capacity, however, is limited 
by the ambient pressure. 
The squeeze-film bearing has been studied as part of 
a program to develop a low-friction suspension for 
the output-axis gimbal of a single-degree-of-freedom 
gyroscope. This study includes a review of the perti-
nent technical literature, the theory of squeeze-film 
lubrication, and design elements pertaining to oscilla-
tion drivers (primarily piezoelectric transducers), con-
centrators, wave extenders, and self-tuning electrical 
drive circuits. The asymptotic theory for the steady-
state squeeze film, including edge correction, is
applied to a circular thrust disc, a conical bearing with 
uniform axial excursion, a cylindrical journal bearing, 
and a spherical bearing with uniform axial excursion. 
A squeeze-film journal bearing employing a floating 
tubular transducer, described in Tech Brief 66-10226 
as a conceptual design, has been fabricated. In an 
experimental study of this bearing, the transducer 
was excited by a self-tuning oscillator. The measured 
load-deflection values were found to be in close agree-
ment with the values derived from the asymptotic 
theory of the squeeze film. The floating tubular trans-
ducer was also used to construct a squeeze-film bear-
ing for simultaneous journal and thrust loads. The 
thrust bearing area of this design is limited by the 
maximum thickness of the tube wall that can be manu-
factured; consequently, its thrust load capacity is 
marginal. 
Note: 
Complete details may be obtained from: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10180 
Patent status: 
No patent action is contemplated by NASA. 
Source: C. H. T. Pan 
of Mechanical Technology, Inc. 
under contract to 
Marshall Space Flight Center 
and P. H. Broussard, Jr. and J. L. Burch 
(MFS-14821) 
Category 05 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Squeeze-film gas bearing technology

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