Ultra-thin gas squeeze film characteristics for finite squeeze numbers are examined by solving the molecular gas film lubrication (MGL) equation, which has a similar form to the conventional Reynolds-type lubrication equation but contains a flow rate coefficient and is valid for arbitrarily small spacings or for arbitrary Knudsen number. We quantitatively clarify by numerical computations that at thin film conditions below several micrometers, pressures generated by squeeze motions are lower than those of continuum flow case and therefore load-carrying capacities are smaller and depend upon film thickness because of the molecular gas effect. For example when the squeeze number is 10 and excursion ratio is 0.5, the load-carrying capacity at 0.1 μm is about one tenth of that at 1 μm.

1.
Fukui
S.
, and
Kaneko
R.
,
1988
a, “
Analysis of Ultra-Thin Gas Film Lubrication Based on Linearized Boltzmann Equation: First Report-Derivation of a Generalized Lubrication Equation Including Thermal Creep Flow
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
110
, p.
253
253
.
2.
Fukui
S.
, and
Kaneko
R.
,
1988
b, “
Experimental Investigation of Externally Pressurized Bearings Under High Knudsen Number Condition
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
112
, p.
144
144
.
3.
Fukui
S.
, and
Kaneko
R.
,
1990
, “
A Database for Interpolation of Poiseuille Flow Rates for High Knudsen Number Lubrication Problems
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
112
, p.
78
78
.
4.
Fukui, S., Matsuda, R., and Kaneko, R., 1995, “On The Physical Meanings of Λ/Q˜p0 and σ/Q˜p0 in Molecular Gas Film Lubrication Problems,” to be published in ASME JOURNAL OF TRIBOLOGY.
5.
Gunter
P.
,
Fischer
U. Ch.
, and
Dransfeld
K.
,
1989
, “
Scanning Near-Field Acoustic Microscopy
,”
Appl. Phys. Val
.
B48
, p.
89
89
.
6.
Hosaka, H., Itao, K., and Kuroda, S., 1994, “Evaluation of Energy Dissipation Mechanisms in Vibrational Microactuators,” Proc. IEEE MEMS Workshop, p. 193.
7.
Maeno, T., and Bogy, D. B., 1992, “Effect of the Hydrodynamic Bearing on Rotor/Stator Contact in a Ring-Type Ultrasonic Motor,” IEEE Trans. Ultrason. Ferroelec., Frec., Contr., Vol. UFFC-39, p. 675.
8.
Matsuda
R.
, and
Fukui
S.
,
1995
, “
Asymptotic Analysis of Ultra-Thin Gas Squeeze Film Lubrication for Infinitely Large Squeeze Number
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
117
, p.
9
9
.
9.
Ono
K.
,
1976
, “
Analysis and Its Experimental Verification of Motion of Mass Supported on Compressible Squeeze Film
,”
Journal of JSLE
, Vol.
18
, No.
10
, p.
773
773
(in Japanese).
10.
Salbu
E. O. J.
,
1964
, “
Compressible Squeeze Films and Squeeze Bearings
,”
ASME Journal of Basic Engineering
, Vol.
86
, No.
2
, p.
335
335
.
11.
Gross, W. A. ed., 1980, Fluid Film Lubrication, Wiley, New York, NY.
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