US008727699B2

(12) United States Patent (10) Patent No.: US 8,727,699 B2

Vetters et al. (45) Date of Patent: May 20, 2014

(54) ROTATING MACHINERY WITH DAMPING USPC ............... 415/33; 415/34; 41.5/109; 415/112:
SYSTEM 415/113:415/119: 415/142; 415/180; 415/229
(58) Field of Classification Search
(75) Inventors: Daniel Kent Vetters, Indianapolis, IN CPC ......... F01D 25/164: F01D 5/26: F01D 25/04;
(US); Timothy Hoffmann, Greenwood, F16C 19/14: F16C 27/045; F16C 2360/23
IN (US); Steven Arlen Klusman, USPC ............. 415/33, 34, 109, 110, 111, 112, 113,
Indianapolis, IN (US) 415/119, 142, 170.1, 180, 229; 384/99
See application file for complete search history.
(73) Assignees: Rolls-Royce Corporation, Indianapolis,
IN (US); Rolls-Royce North American (56) References Cited
Technologies, Inc., Indianapolis, IN
(US) U.S. PATENT DOCUMENTS

(*) Notice: Subject to any disclaimer, the term of this :23: A 88. {Ap
patent is extended or adjusted under 35 4,952.076 A 8/1990 Wiley, III et al.
U.S.C. 154(b) by 727 days. 5,080,499 A 1/1992 Klusman et al.
5,201,585 A 4/1993 Gans et al.
(21) Appl. No.: 12/904,730 5,344,239 A 9, 1994 Stallone et al.
6,910,863 B2 6/2005 Scardicchio et al.
1-1. 6,942.451 B1 9, 2005 Alexander et al.
(22) Filed: Oct. 14, 2010 7.625,121 B2 * 12/2009 Pettinato et al. ................ 384.99
2002fOO67871 A1* 6/2002 BOS et al. ........................ 384.99
(65) Prior Publication Data
(Continued)
US 2011 FO171012 A1 Jul. 14, 2011
OTHER PUBLICATIONS
Related U.S. Application Data International Search Report and Written Opinion, PCT/US2010/
(60) Provisional application No. 61/290,702, filed on Dec. 062377, May 2, 2011.
29, 2009.
Primary Examiner — Igor Kershteyn
(51) Int. Cl. (74) Attorney, Agent, or Firm — Krieg DeVault LLP
FOID 25/00 (2006.01)
FOID 25/6 (2006.01) (57) ABSTRACT
FOID 5/26 (2006.01) One embodiment of the present invention is a damping sys
FOID 25/04 (2006.01) tem for rotating machinery Such as gas turbine engines. Other
FI6C 9/14 (2006.01) embodiments include apparatuses, systems, devices, hard
FI6C 27/04 (2006.01) ware, methods, and combinations for damping systems. Fur
(52) U.S. Cl. ther embodiments, forms, features, aspects, benefits, and
CPC ................ FOID 25/164 (2013.01); F0ID 5/26 advantages of the present application shall become apparent
(2013.01); F0ID 25/04 (2013.01); F16C 19/14 from the description and figures provided herewith.
(2013.01); F16C 27/045 (2013.01); F16C
2360/23 (2013.01) 21 Claims, 4 Drawing Sheets
 US 8,727,699 B2
Page 2

(56) References Cited 2003/01893.82 A1 10/2003 Tornquist et al.

2004/0042693 A1 3/2004 Dubreuil et al.
U.S. PATENT DOCUMENTS 2007, OO86685 A1 4/2007 Klusman et al.
2007/0248293 A1* 10, 2007 Pettinato et al. ................ 384.99
2002/0076124 A1* 6/2002 BOS et al. ........................ 384/99 2009,0263058 A1 10, 2009 Gibbons
2002/O127102 A1 9/2002 Corattiyil et al.
2003/0039538 A1 2/2003 Allmon et al. * cited by examiner
U.S. Patent May 20, 2014 Sheet 1 of 4 US 8,727,699 B2
U.S. Patent May 20, 2014 Sheet 2 of 4 US 8,727,699 B2
U.S. Patent May 20, 2014 Sheet 3 of 4 US 8,727,699 B2

46

The R-4T, 48

42 50
36 7254
88192 70
38

F.G. 3
U.S. Patent May 20, 2014 Sheet 4 of 4 US 8,727,699 B2

78
76

78

80

76

FIG. 4
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1. 2
ROTATING MACHINERY WITH DAMPNG (s) are contemplated as being within the scope of the present
SYSTEM invention. Further, any other applications of the principles of
the invention, as illustrated and/or described herein, as would
CROSS REFERENCE TO RELATED normally occur to one skilled in the art to which the invention
APPLICATIONS pertains, are contemplated as being within the scope of the
present invention.
The present application claims the benefit of U.S. Provi Referring now to the drawings, and in particular FIG. 1,
sional Patent Application 61/290,702, filed Dec. 29, 2009, there is shown a rotating machine in the form of a gas turbine
and is incorporated herein by reference. engine 10. Although embodiments of the present invention
10 are described herein with respect to a gas turbine engine, it
GOVERNMENT RIGHTS will be understood that the present invention is also appli
cable to other types of rotating machines.
The present application was made with United States gov Gas turbine engine 10 includes a compressor 12, a com
ernment support under Contract No. XO2370220E awarded bustor 14 and a turbine 16. Compressor 12 is mechanically
by the United States government. The United States govern 15 coupled to turbine 16 via a shaft 18, which form a part of a
ment may have certain rights in the present application. rotor system 20. Combustor 14 is fluidly disposed between
compressor 12 and turbine 16. Compressor 12, combustor 14
FIELD OF THE INVENTION and turbine 16 are housed within and Supported by an engine
case system 22, which generally includes mounting features
The present invention relates to rotating machinery Such as for mounting gas turbine engine 10 in an air vehicle. Such as
gas turbine engines, and more particularly, to a damping an aircraft or missile system.
system for use in rotating machinery. Coupled to engine case system 22 are static structures,
including a front bearing Support 24 and an aft bearing Sup
BACKGROUND port 26. Housed within front bearing support 24 is a rolling
25 element bearing 28 which supports the front portion of rotor
Damping systems that effectively damp vibrations in rotat system 20, e.g., including compressor 12 and the front portion
ing structures, such as rotor systems in a gas turbine engines of shaft 18. Rolling element bearing 28 is a ball thrust bearing.
or other rotating machinery, remain an area of interest. Some In other embodiments of the present invention, it is alterna
existing systems have various shortcomings, drawbacks, and tively considered that rolling element bearing 28 may be one
disadvantages relative to certain applications. Accordingly, 30 or more of a rollerbearing and/or other type of rolling element
there remains a need for further contributions in this area of bearing. As a thrust bearing, rolling element bearing 28 trans
technology. mits both thrust loads and radial loads from rotor system 20
into engine case system 22 via front bearing Support 24.
SUMMARY Housed within aft bearing support 26 is a rolling element
35 bearing 30 which supports the aft portion of rotor system 20,
One embodiment of the present invention is a damping e.g., including turbine 16 and the aft portion of shaft 18.
system for rotating machinery Such as gas turbine engines. Rolling element bearing 30 is a roller bearing. It is alterna
Other embodiments include apparatuses, systems, devices, tively considered that in other embodiments, rolling element
hardware, methods, and combinations for damping systems. bearing 30 may be one or more of a ball bearing and/or other
Further embodiments, forms, features, aspects, benefits, and 40 type of rolling element bearing. Rolling element bearing 30
advantages of the present application shall become apparent transmits radial loads from rotor System 20 into engine case
from the description and figures provided herewith. system 22 via aft bearing Support 26.
In the depiction of FIG. 1, each of rolling element bearing
BRIEF DESCRIPTION OF THE DRAWINGS 28 and rolling element bearing 30 are depicted as being
45 mounted directly on shaft 18. However, it will be understood
The description herein makes reference to the accompany that the depiction of FIG. 1 is schematic in nature and not
ing drawings wherein like reference numerals refer to like representative of any particular scheme for mounting rolling
parts throughout the several views, and wherein: element bearing 28 and rolling element bearing 30. Rather,
FIG. 1 schematically depicts a gas turbine engine in accor embodiments of the present invention may incorporate one or
dance with an embodiment of the present invention. 50 more of many different possible mounting schemes.
FIG.2 is a cross section of a damping system in accordance During steady state operation of gas turbine engine 10,
with an embodiment of the present invention. atmospheric air is drawn into and compressed by compressor
FIG. 3 is an enlarged cross section of the damping system 12. The compressed airis discharged from compressor 12 into
of FIG. 2. combustor 14, where fuel is added to the compressed air and
FIG. 4 is a cross sectional view of an isolator spring 55 the mixture is ignited. The resulting hot gases are Supplied to
employed in the damping system embodiment of FIG. 2. turbine 16, which extracts mechanical energy to drive com
pressor 12, and discharges the hot gases, e.g., in the form of jet
DETAILED DESCRIPTION thrust.
The operation of gas turbine engine 10 results in steady
For purposes of promoting an understanding of the prin 60 state and dynamic loads on rotor system 20, including aero
ciples of the invention, reference will now be made to the dynamic, gyroscopic, rotor mass and unbalance loads. The
embodiments illustrated in the drawings, and specific lan rotor system 20 loads are transmitted by rolling element bear
guage will be used to describe the same. It will nonetheless be ings 28 and 30 to engine case system 20.
understood that no limitation of the scope of the invention is Rotor system 20 aerodynamic loads include axial thrust
intended by the illustration and description of certain embodi 65 loads. Aerodynamically imposed thrust loads may be tuned,
ments of the invention. In addition, any alterations and/or in conjunction with the radial loads anticipated during engine
modifications of the illustrated and/or described embodiment operation, to optimize the life of the thrust bearing, i.e., roll
 US 8,727,699 B2
3 4
ing element bearing 28. For example, balance pistons (not race 38. Split inner race 36 includes an inner race pilot surface
shown) may be employed to achieve desired steady state 56 defined by an inner race pilot diameter. Bearing cage 34
thrust loads. includes a static inner piloting surface 58 defined by an inside
Gyroscopic loads occur when rotor System 20 is rotating at pilot diameter.
the same time engine 10 is rotated in a direction having a 5 Defined between outer race pilot surface 54 and static inner
component axis of rotation inclined 90° from the axis of piloting surface 58 is a cavity 60. Damper ring 40, seal 42,
rotation of rotor System 20. Gyroscopic loading results in seal 44, isolator spring 46 and isolator spring 48 are disposed
bending loads in rotor system 20 and radial loads, which are within cavity 60. Cavity 60 is charged with a fluid, e.g., a
reacted by both rolling element bearing 28 and rolling ele Viscous damping fluid, Such as engine lubricating oil or a
ment bearing 30. 10 grease, which is employed in conjunction with damper ring
Rotor mass loads result from the mass of rotor system 20 in 40 to provide damping. Cavity 60 may be charged with the
conjunction with gravity and air vehicle acceleration in a damping fluid by a pressurized lubrication system (not
direction perpendicular to the axis of rotation of rotor system shown) of gas turbine engine 10.
20. Depending on the acceleration experienced by the air Damper ring 40 includes a plurality of fluid transfer holes
vehicle in a direction perpendicular to the axis of rotation of 15 62 disposed about the circumference of damper ring 40,
rotor system 20, the rotor mass loads may be greater or lesser which help to distribute the damping fluid about the inner and
than the weight of rotor system 20. Rotor mass loads are outer periphery of damper ring 40. The damping fluid may be
radial loads, and are reacted by both rolling element bearing Supplied by a passage (not shown) through bearing cage 34.
28 and rolling element bearing 30. Damper ring 40 is an annular Squeeze film damper ring,
Dynamic loads include both unbalance loads and critical and is structured to provide damping of rotor system 20 based
rotor mode responses, both of which are reacted by both on the radial displacements of split outer race 38 that result
rolling element bearing 28 and rolling element bearing 30. from critical rotor mode responses, e.g., during the startup of
Unbalance loads result primarily from manufacturing toler gas turbine engine 10. In particular, damper ring 40 is opera
ances and wear of rotor system 20 components. Critical rotor tive to provide viscous damping of radial loads generated in
mode responses may occur during startup of gas turbine 25 rotor system 20 using the viscous damping fluid, based on
engine 10 as rotor System 20 accelerates through critical clearances between damper ring 40, inner piloting surface 58
speeds, i.e., rotor speeds corresponding to resonant frequen of bearing cage 34 and outer race piloting Surface 54 of rolling
cies of rotor system 20. The critical rotor mode responses may element bearing 28.
result in Substantial dynamic radial loads. In order to damp Damper ring 40 is a dual-sided damper ring, and includes
the critical rotor mode responses as rotor system 20 passes 30 damper clearance surfaces 64, 66, 68, 70, 72 and 74. Damper
through resonant frequencies, gas turbine engine 10 includes clearance surfaces 64, 66, 68, 70, 72 and 74 are diametrically
a damping system. sized to provide a predetermined amount of damping in con
Referring now to FIG. 2, gas turbine engine 10 includes a junction with the diameters of outer race pilot surface 54 of
Squeeze film damping system 32 structured to damp vibra split outer race 38 and inner piloting surface 58 of bearing
tions passing from rotor system 20 through rolling element 35 cage 34. Being a dual-sided damper ring, damping is per
bearing 28 into a static structure. In one form, the static formed based on the diametral clearance between damper
structure is front bearing Support 24. In other embodiments, clearance surfaces 64, 66 and 68 of damper ring 40 and inner
other static structures may be employed, e.g., including com piloting Surface 58 of bearing cage 34, and damping is also
ponents affixed or coupled to bearing Support 24 through performed based on the diametral clearance between damper
which dynamic loads pass before or after reaching bearing 40 clearance surfaces 70, 72 and 74 of damper ring 40 and outer
Support 24. A similar damping system may be structured to race pilot surface 54 of rolling element bearing 28. Damping
damp vibrations passing from rotor System 20 through rolling is thus performed on both sides of damper ring 40.
element bearing 30 into aft bearing support 26. For example, because rotor system 20 is spinning during
As depicted in FIG. 2, front bearing support 24 includes a the operation of gas turbine engine 10, the radial displace
bearing cage 34. Rolling element bearing 28 includes a split 45 ment resulting from the critical rotor mode responses of rotor
inner race 36 and a split outer race 38. Split outer race 38 of system 20 generates an orbital motion in split outer race 38.
rolling element bearing 28 is Subject to radial displacements That is, the radial displacement of split outer race 38 rotates
during the operation of gas turbine engine 10. The radial approximately about the axis of revolution of rotor system 20.
displacements may result from critical rotor mode responses The orbiting radial displacement of split outer race 38 results
during startup of gas turbine engine 10. Radial displacements 50 in a rotating front of oil being “squeezed' between outer race
may also result from rotor system 20 unbalance loads and pilot surface 54 of split outer race 38 and damper ring 40, and
gyroscopically induced loads. between damper ring 40 and static inner piloting surface 58 of
Damping system 32 includes a damper ring 40, a seal 42 bearing cage 34, which provides viscous damping due to the
disposed on one side of damperring 40, a seal 44 disposed on viscosity characteristic of the fluid in cavity 60. In other
the other side of damper ring 40, an isolator spring 46 dis 55 embodiments, a single-sided damper ring may be employed.
posed on one side of damper ring 40 and an isolator spring 48 In one form, a centering force to center split outer race 38
disposed on the other side of damper ring 40. In one form, relative to bearing cage 34 is provided by each of isolator
damping system32 is a squeeze-film damping system. Damp spring 46 and isolator spring 48. In one form, isolator spring
ing system 32 and split outer race 38 are axially retained 46 and isolator spring 48 are annular springs, each having
between an aft wall 50 of bearing cage 34 and a forward 60 alternating contact between inner piloting surface 58 of bear
structure 52 affixed to front bearing support 24. ing cage 34 and outer race pilot Surface 54 of rolling element
Referring now to FIG.3 in conjunction with FIG. 2, damp bearing 28. In other embodiments, other types of springs may
ing system 32 is further described. be employed. Isolator spring 46 and isolator spring 48 absorb
Split outer race 38 includes an outer race pilot surface 54 the radial displacement of rolling element bearing 28 relative
defined by an outer race pilot diameter. As a piloting feature, 65 to bearing cage 34. The inclusion of one or more isolator
outer race pilot surface 54 is a radial positioning Surface, springs allows for dynamic tuning. For example, in some
which in the present embodiment radially positions split outer embodiments, isolator spring 46 and/or isolator spring 48
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may be used to alter the stiffness of the bearing support 54 of split outer race 38 and inner piloting surface 58 of
system, e.g., in which case the stiffness of isolator spring 46 bearing cage 34 in providing Squeeze film damping of rotor
and/or isolator spring 46 are selected so as to tune the system 20.
dynamic characteristics of the bearing Support system. Although the illustrated embodiment of damping system
For example, referring now to FIG. 4, a cross section 32 is disposed between split outer race 38 and bearing cage 34
through isolator spring 48 is depicted. Isolator spring 46 is in the present embodiment, it is alternatively contemplated
structured similar to isolator spring 48. In one form, isolator that damping system 32 may be disposed between split inner
springs 46 and 48 are segmented rings. In other embodiments, race 36 and a portion of rotor system 20 in other embodi
isolator springs 46 and 48 may be split rings or may be ments. In still other embodiments, it is contemplated that
continuous rings. In still other embodiments, isolator springs 10
other gas turbine engine 10 components may be intermedi
46 and 48 may take other forms. Isolator spring 48 includes a ately disposed between split outer race 38 and damper ring 40
plurality of outer contact portions 76, a plurality of inner and/or between damper ring 40 and bearing cage 34, in which
contact portions 78, and a flexural portion 80 disposed case damping is performed based on the damping fluid Sur
between each outer contact portion 76 and inner contact por rounding damper ring 40 in conjunction with the clearances
tion 78. Outer contact portions 76 are piloted by inner piloting 15
surface 58 of bearing cage 34. Inner contact portions 78 are between damper ring 40 and any such intermediately dis
piloted by outer race pilot surface 54 of split outer race 38. posed components. In yet other embodiments, it is contem
Radial excursions of split outer race 38 displace inner contact plated that damping system 32 may be employed for inter
portions 78 relative to outer contact portions 76, resulting in shaft damping, wherein damping is performed between two
deflection of flexural portions 80, which generates restoring or more rotor systems.
forces in a direction opposite the direction of deflection. An embodiment of the present invention may include a
Although the present embodiment employs two (2) isolator rotating machine with a first component having a first com
springs 46 and 48, it is alternatively contemplated that other ponent Surface Subject to radial displacement during opera
embodiments may employ fewer or greater numbers of iso tion of the rotating machine. The first component Surface may
lator springs, or may not include any Such isolator springs. 25 be defined by a first diameter. The second component may
Referring again to FIG.3, in one form, each of seals 42 and have a second component Surface spaced apart from the first
44 is pressure assisted, i.e., a self-charging seal, wherein the component Surface. The second component Surface may be
pressure of the fluid sought to be sealed assists in maintaining defined by a second diameter different from the first diameter.
contact between the relevant sealing Surfaces. In other A Squeeze film damper disposed in a cavity may be defined
embodiments, other seal types may be employed. Each of 30 between the first component Surface and the second compo
seals 42 and 44 are structured to receive charging pressure nent Surface. The Squeeze film damper may be structured to
from the damping fluid contained in cavity 60. Seals 42 and provide damping based on the radial displacement. A seal
44 are polymeric in the present embodiment, e.g., a polyim disposed adjacent to the Squeeze film damper may have a seal
ide, although other materials may be employed in other having a first sealing Surface and a second sealing Surface.
embodiments of the present invention. By employing seals 42 35 The first sealing Surface may be structured to seal against the
and 44 to seal against the same Surfaces employed for damp first component Surface at the first diameter. The second seal
ing via damper ring 40, e.g., piloting Surfaces 54 and 58, the ing Surface may be structured to seal against the second
envelope requirements and costs associated with seal glands component Surface at the second diameter.
for other seal arrangements may be avoided. In one refinement of the embodiment a squeeze film
Each of seals 42 and 44 are bifurcated seals disposed adja 40 damper is structured as an annular Squeeze film damper ring.
cent to damperring 40, and include a body 82, an outer leg 84. In another refinement of the embodiment the seal is a
an inner leg 86, and a hollow 88 defined between body 82, self-charging seal.
outer leg 84 and inner leg 86. Each outer leg 84 extends from In another refinement of the embodiment the seal is struc
body 82, and includes a sealing surface 90 disposed thereon tured to receive a charging pressure from damping fluid in
and positioned in proximity to inner piloting surface 58 of 45 said cavity.
bearing cage 34. Sealing surface 90 is structured to seal In another refinement of the embodiment the seal is a
against static inner piloting Surface58, i.e., at the bearing cage bifurcated seal having a first leg and a second leg. The first
34 inner pilot diameter. Each inner leg 86 extends from body sealing Surface is disposed on the first leg and the second
82, and includes a sealing surface 92 disposed thereon and sealing Surface is disposed on the second leg.
positioned in proximity to outer race pilot surface 54 of roll 50 In another refinement of the embodiment the seal includes
ing element bearing 28. Sealing surface 92 is structured to a hollow defined between the first leg and the second leg. The
seal against outer race pilot Surface 54, i.e., at the outer race hollow is open to the cavity.
pilot diameter of split outer race 38. In another refinement of the embodiment the first compo
Each hollow 88 is open to cavity 60, and exposes outer leg nent is a portion of a rolling element bearing. The second
84 and inner leg 86 to the pressure of the damping fluid 55 component is a static bearing Support structure of the rotating
surrounding damper ring 40 in cavity 60. The pressure of the machine.
damping fluid acts on outer leg 84 and inner leg 86 in the In another refinement of the embodiment the first compo
direction of sealing surface 90 and sealing surface 92, respec nent is one of an inner race and an outer race of the rolling
tively, during the operation of gas turbine engine 10. This element bearing. The first diameter is the one of a correspond
pressure helps to retain sealing Surface 90 and sealing Surface 60 ing inner race pilot diameter and outer race pilot diameter of
92 in sealing contact with inner piloting surface 58 of bearing the rolling element bearing.
cage 34 and outer race pilot surface 54 of rolling element In another refinement of the embodiment the squeeze film
bearing 28, respectively, during the operation of gas turbine damper is a dual sided damper ring structured to perform
engine 10. The pressure thus assists seals 42 and 44 in retain damping on both sides of the dual sided damper ring.
ing the damping fluid in cavity 60, which is used by damper 65 In another refinement of the embodiment the cavity is
clearance surfaces 64, 66, 68.70, 72 and 74 of damper ring 40 charged with a fluid that is employed in conjunction with the
in conjunction with the diameters of outer race pilot Surface Squeeze film damper to provide the damping.
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Another embodiment of the present invention may include for damping the variable load and for sealing the means for
a gas turbine engine. The gas turbine engine may include a damping. The sealing may be operative to seal between the
rotating engine structure, a static engine structure having a static structure pilot diameter and the one of the inner race
static structure pilot diameter, and a rolling element bearing pilot diameter and the outer race pilot diameter.
structured to transmit a load from the rotating engine struc In a refinement of the embodiment the rotating machine
ture to the static engine structure. The rolling element bearing may include a means for absorbing radial displacement
may have an inner race and an outer race. The inner race may between the static structure pilot diameter and the one of the
have an inner race pilot diameter and the outer race may have inner race pilot diameter and the outer race pilot diameter.
an outer race pilot diameter. The static structure pilot diam Another embodiment of the present invention may be a
eter and one of the inner race pilot diameter and the outer race 10 damper system for rotating machinery which may include a
pilot diameterform a cavity and a damping system for damp Squeeze film damper disposed in a cavity defined between a
ing the load. The damping system may include a squeeze film diameter of a static structure of the rotating machinery and
damper disposed in the cavity. The cavity also may contain a one of an inner race diameter and an outer race diameter of a
Viscous damping fluid. The squeeze film damper may be rolling element bearing of the rotating machinery. The cavity
operative to provide Viscous damping of the load using the 15 also may contain a viscous damping fluid. The Squeeze film
Viscous damping fluid based on clearances between the static damper may be operative to provide Viscous damping of a
engine structure at the static structure pilot diameter and the load using the Viscous damping fluid based on clearances
rolling element bearing at the one of the inner race pilot between the static structure diameter and the one of the inner
diameter and the outer race pilot diameter. A seal may be race diameter and the outer race diameter. The embodiment
disposed at least partially in the cavity. The seal may have a may also include a seal disposed at least partially in the cavity.
first sealing Surface and a second sealing Surface. The first The seal may have a first sealing Surface and a second sealing
sealing Surface may be structured to seal against the static Surface. The first sealing Surface may be structured to seal
engine structure at the static structure pilot diameter. The against the static structure at the diameter of the static struc
second sealing Surface may be structured to seal against the ture. The second sealing Surface may be structured to seal
rolling element bearing at the one of the inner race pilot 25 against the rolling element bearing at the one of the inner race
diameter and the outer race pilot diameter. diameter and the outer race diameter.
In a refinement of the embodiment the gas turbine engine While the invention has been described in connection with
may include an isolator spring disposed in the cavity and what is presently considered to be the most practical and
piloted by the static engine structure at the static structure preferred embodiment, it is to be understood that the inven
pilot diameterand the rolling element bearing at the one of the 30 tion is not to be limited to the disclosed embodiment(s), but on
inner race pilot diameter and the outer race pilot diameter. The the contrary, is intended to cover various modifications and
isolator sprint is structured to absorb radial displacement equivalent arrangements included within the spirit and scope
between the rolling element bearing and the static engine of the appended claims, which scope is to be accorded the
Structure. broadest interpretation so as to encompass all such modifica
In another refinement of the embodiment the isolator 35 tions and equivalent structures as permitted under the law.
spring may be an annular spring having alternating contact Furthermore it should be understood that while the use of the
between the static structure at the static structure pilot diam word preferable, preferably, or preferred in the description
eter and the rolling element bearing at the one of the inner race above indicates that feature so described may be more desir
pilot diameter and the outer race pilot diameter. able, it nonetheless may not be necessary and any embodi
In another refinement of the embodiment the seal may be a 40 ment lacking the same may be contemplated as within the
self-charging seal. Scope of the invention, that scope being defined by the claims
In another refinement of the embodiment the seal may be that follow. In reading the claims it is intended that when
structured to receive a charging pressure from the Viscous words such as an.” “at least one' and “at least a portion
damping fluid in the cavity. are used, there is no intention to limit the claim to only one
In another refinement of the embodiment the seal may be a 45 item unless specifically stated to the contrary in the claim.
bifurcated seal having a first leg and a second leg. The first Further, when the language “at least a portion' and/or “a
sealing Surface may be on the first leg. The second sealing portion' is used the item may include a portion and/or the
Surface may be disposed on the second leg. entire item unless specifically stated to the contrary.
In another refinement of the embodiment the seal may
include a hollow defined between the first leg and the second 50 What is claimed is:
leg. The hollow may open to the cavity. 1. A rotating machine, comprising:
In another refinement of the embodiment the squeeze film a first component having a first component Surface Subject
damper may be operative to provide viscous damping of the to radial displacement during operation of said rotating
load using the Viscous damping fluid based on clearances machine, said first component Surface being defined by
between the static engine structure at the static structure pilot 55 a first diameter;
diameter and the rolling element bearing at the outer race pilot a second component having a second component Surface
diameter. spaced apart from said first component Surface, said
Another embodiment of the present invention may be a second component Surface being defined by a second
rotating machine which may include a rotating structure, a diameter different from said first diameter;
static structure having a static structure pilot diameter, and a 60 a Squeeze film damper disposed inacavity defined between
rolling element bearing structured to transmit a variable load said first component Surface and said second component
from the rotating structure to the static structure. The rolling Surface, said Squeeze film damper being structured to
element bearing may have an inner race and an outer race. The provide damping based on said radial displacement; and
inner race may have an inner race pilot diameter and the outer a seal disposed adjacent to said Squeeze film damper, said
race may have an outer race pilot diameter. The static struc 65 seal having a first sealing Surface and a second sealing
ture pilot diameterandone of the inner race pilot diameterand Surface, wherein said first sealing Surface is structured to
the outer race pilot diameter may form a cavity therebetween seal against said first component Surface at said first
 US 8,727,699 B2
10
diameter, and wherein said second sealing Surface is 12. The gas turbine engine of claim 11, further comprising
structured to seal against said second component Surface an isolator spring disposed in said cavity and piloted by said
at said second diameter. static engine structure at said Static structure pilot diameter
2. The rotating machine of claim 1, wherein said Squeeze and said rolling element bearing at said one of said inner race
film damper is structured as an annular Squeeze film damper pilot diameter and said outer race pilot diameter, wherein said
ring. isolator spring is structured to absorb radial displacement
3. The rotating machine of claim 1, wherein said seal is a between said rolling element bearing and said Static engine
self-charging seal. Structure.
4. The rotating machine of claim 3, wherein said seal is 13. The gas turbine engine of claim 12, wherein said iso
structured to receive a charging pressure from damping fluid 10 lator spring is an annular spring having alternating contact
in said cavity. between said static engine structure at said static structure
5. The rotating machine of claim 1, wherein said seal is a pilot diameter and said rolling element bearing at said one of
bifurcated seal having a first leg and a second leg; wherein said inner race pilot diameter and said outer race pilot diam
eter.
said first sealing Surface is disposed on said first leg; and 15 14. The gas turbine engine of claim 11, wherein said seal is
wherein said second sealing Surface is disposed on said sec a self-charging seal.
ond leg. 15. The gas turbine engine of claim 14, wherein said seal is
6. The rotating machine of claim 5, wherein said seal structured to receive a charging pressure from said Viscous
includes a hollow defined between said first leg and said damping fluid in said cavity.
second leg, and wherein said hollow is open to said cavity. 16. The gas turbine engine of claim 11, wherein said seal is
7. The rotating machine of claim 1, wherein said first a bifurcated seal having a first leg and a second leg; wherein
component is a portion of a rolling element bearing; and said first sealing Surface is disposed on said first leg; and
wherein said second component is a static bearing Support wherein said second sealing Surface is disposed on said sec
structure of said rotating machine. ond leg.
8. The rotating machine of claim 7, wherein said first 25 17. The gas turbine engine of claim 16, wherein said seal
component is one of an inner race and an outer race of said includes a hollow defined between said first leg and said
rolling element bearing, and wherein said first diameter is second leg, and wherein said hollow is open to said cavity.
said one of a corresponding inner race pilot diameter and 18. The gas turbine engine of claim 11, wherein said
outer race pilot diameter of said rolling element bearing. Squeeze film damper is operative to provide viscous damping
9. The rotating machine of claim 1, wherein said Squeeze 30 of said load using said viscous damping fluid based on clear
film damper is a dual sided damper ring structured to perform ances between said Static engine structure at said static struc
damping on both sides of said dual sided damper ring. ture pilot diameter and said rolling element bearing at said
10. The rotating machine of claim 1, wherein said cavity is outer race pilot diameter.
charged with a fluid that is employed in conjunction with said 19. A rotating machine, comprising:
Squeeze film damper to provide said damping. 35 a rotating structure;
11. A gas turbine engine, comprising: a static structure having a static structure pilot diameter;
a rotating engine structure; a rolling element bearing structured to transmit a variable
a static engine structure having a static structure pilot diam load from said rotating structure to said static structure,
eter; said rolling element bearing having an inner race and an
a rolling element bearing structured to transmit a load from 40 outer race, said inner race having an inner race pilot
said rotating engine structure to said static engine struc diameter and said outer race having an outer race pilot
ture, said rolling element bearing having an inner race diameter, wherein said static structure pilot diameter and
and an outer race, said inner race having an inner race one of said inner race pilot diameter and said outer race
pilot diameter and said outer race having an outer race pilot diameter form a cavity therebetween;
pilot diameter, wherein said static structure pilot diam 45 means for damping said variable load; and
eter and one of said inner race pilot diameter and said means for sealing said means for damping, said means for
outer race pilot diameter form a cavity therebetween; sealing being operative to seal between said static struc
and ture pilot diameter and said one of said inner race pilot
a damping system for damping said load, said damping diameter and said outer race pilot diameter.
system including: 50 20. The rotating machine of claim 19, further comprising
a Squeeze film damper disposed in said cavity, said cav means for absorbing radial displacement between said static
ity also containing a viscous damping fluid, wherein structure pilot diameter and said one of said inner race pilot
said Squeeze film damper is operative to provide vis diameter and said outer race pilot diameter.
cous damping of said load using said viscous damping 21. A damper system for rotating machinery, comprising:
fluid based on clearances between said static engine 55 a Squeeze film damper disposed inacavity defined between
structure at said static structure pilot diameter and a diameter of a static structure of said rotating machinery
said rolling element bearing at said one of said inner and one of an inner race diameter and an outer race
race pilot diameter and said outer race pilot diameter, diameter of a rolling element bearing of said rotating
and machinery, said cavity also containing a viscous damp
a seal disposed at least partially in said cavity, said seal 60 ing fluid, wherein said Squeeze film damper is operative
having a first sealing Surface and a second sealing to provide viscous damping of a load using said viscous
Surface, wherein said first sealing Surface is structured damping fluid based on clearances between said static
to seal against said static engine structure at said static structure diameter and said one of said inner race diam
structure pilot diameter, and wherein said second eter and said outer race diameter, and
sealing Surface is structured to seal against said roll 65 a seal disposed at least partially in said cavity, said seal
ing element bearing at said one of said inner race pilot having a first sealing Surface and a second sealing Sur
diameter and said outer race pilot diameter. face, wherein said first sealing Surface is structured to
 US 8,727,699 B2
11 12
seal against said static structure at said diameter of said
static structure, and wherein said second sealing Surface
is structured to seal against said rolling element bearing
at said one of said innerrace diameter and said outer race
diameter. 5