U.S. patent application number 17/124675 was filed with the patent office on 2022-06-23 for gear baffle.
The applicant listed for this patent is PRATT & WHITNEY CANADA CORP.. Invention is credited to Marcin REJMAN.
Application Number | 20220195945 17/124675 |
Document ID | / |
Family ID | |
Filed Date | 2022-06-23 |
United States Patent
Application |
20220195945 |
Kind Code |
A1 |
REJMAN; Marcin |
June 23, 2022 |
GEAR BAFFLE
Abstract
A gear baffle, a gearbox of a gas turbine engine including a
gear baffle, and a method of installing a gear baffle adjacent to a
gear in a gearbox of a gas turbine engine are disclosed. The
gearbox includes a housing, having disposed therein a gear, and a
baffle adjacent to the gear to interact with lubricant fluid around
the gear. The baffle includes a first interface for attaching the
baffle to a structure to a first side of the gear, and a second
interface for attaching the baffle to a structure to a second,
axially opposite, side of the gear. The second interface may be
axially spaced apart from the first interface by an axial distance.
The baffle may include a main wall interconnecting the first
interface with the second interface. The main wall may include a
compliant corrugation that accommodates a variation in the axial
distance between the first interface and the second interface.
Inventors: |
REJMAN; Marcin; (Rzeszow,
PL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PRATT & WHITNEY CANADA CORP. |
Longueuil |
|
CA |
|
|
Appl. No.: |
17/124675 |
Filed: |
December 17, 2020 |
International
Class: |
F02C 7/36 20060101
F02C007/36; F16H 57/04 20060101 F16H057/04; F16H 57/02 20060101
F16H057/02 |
Claims
1. A gear baffle for interacting with a lubricant fluid around a
gear in a gas turbine engine, the gear baffle comprising: a first
interface for attaching the gear baffle to a structure disposed to
a first side of the gear; a second interface for attaching the gear
baffle to a structure disposed to a second side of the gear
opposite the first side of the gear, the second interface being
spaced apart from the first interface by a distance; and a main
wall interconnecting the first interface with the second interface,
the main wall including a corrugation that is deformable to allow
the main wall to accommodate a variation in the distance between
the first interface and the second interface; wherein: the first
interface is disposed on a first sidewall attached to the main
wall; and a thickness of the first sidewall is greater than a
thickness of the main wall at a location of the corrugation.
2. The gear baffle of claim 1, wherein: the main wall has an inner
side for facing the gear; and the corrugation defines a ridge on
the inner side of the main wall.
3. The gear baffle of claim 2, wherein: the main wall has an outer
side opposite the inner side; and the corrugation defines a groove
on the outer side of the main wall.
4. The gear baffle of claim 1, wherein the corrugation is disposed
substantially midway between the first interface and the second
interface.
5. (canceled)
6. The gear baffle of claim 1, wherein: the second interface is
disposed on a second sidewall attached to the main wall; and a
thickness of the second sidewall is greater than the thickness of
the main wall at the location of the corrugation.
7. The gear baffle of claim 1, wherein the main wall is
perforated.
8. The gear baffle of claim 1, wherein the first interface includes
a threaded through hole.
9. The gear baffle of claim 8, wherein: the second interface
includes an unthreaded through hole; and the threaded and
unthreaded through holes are substantially parallel.
10. A gearbox of a gas turbine engine, the gearbox comprising: a
housing; a gear disposed inside the housing, the gear being
rotatable about an axis; a baffle disposed inside the housing and
adjacent the gear to interact with lubricant fluid around the gear,
the baffle including: a first interface for attaching the baffle
relative to the gear, the first interface being disposed to a first
side of the gear; a second interface for attaching the baffle
relative to the gear, the second interface being disposed to a
second side of the gear axially opposite the first side of the gear
relative to the axis, the second interface being axially spaced
apart from the first interface by an axial distance; and a main
wall interconnecting the first interface with the second interface,
the main wall including an axially-deformable corrugation that
allows the main wall to accommodate a variation in the axial
distance between the first interface and the second interface;
wherein: the first interface is disposed on a first sidewall of the
baffle attached to the main wall; the second interface is disposed
on a second sidewall of the baffle attached to the main wall; the
main wall, the first sidewall and the second sidewall cooperatively
define a receptacle for receiving part of the gear therein; the
main wall has a radially-inner side facing the gear; the
corrugation defines a ridge on the radially-inner side of the main
wall; the gear has two gear faces axially separated by an axial
gap; and the ridge extends radially into the axial gap between the
two gear faces.
11. (canceled)
12. The gearbox of claim 10, wherein: the main wall has a
radially-outer side opposite the radially-inner side; and the
corrugation defines a groove on the radially-outer side of the main
wall.
13. (canceled)
14. The gearbox of claim 10, wherein a thickness of the first
sidewall is greater than a thickness of the main wall at a location
of the corrugation.
15. The gearbox of claim 10, wherein: the first interface is one of
two first interfaces disposed to the first side of the gear for
attaching the baffle relative to the gear; and the second interface
is one of two second interfaces disposed to the second side of the
gear for attaching the baffle relative to the gear.
16. The gearbox of claim 10, wherein: the first sidewall is
oriented transversely to the main wall; the first interface
includes a threaded hole extending through the first sidewall; the
second sidewall is oriented transversely to the main wall; and the
second interface includes an unthreaded hole extending through the
second sidewall, the threaded and unthreaded holes being
substantially parallel.
17. A method of installing a gear baffle adjacent to a gear in a
gearbox of a gas turbine engine, the gear being rotatable about an
axis, the method comprising: attaching a first portion of the gear
baffle to a structure disposed to a first side of the gear;
attaching a second portion of the gear baffle to a structure
disposed to a second side of the gear, the second portion being
axially spaced apart from the first portion by an axial distance
relative to the axis; and causing a main wall interconnecting the
first portion and the second portions of the gear baffle to
accommodate a variation in the axial distance between the first
portion and the second portion by deforming an axially-deformable
corrugation formed into the main wall.
18. The method of claim 17, wherein: the gear has two gear faces
that are axially separated by an axial gap relative to the axis;
the corrugation defines a ridge on the main wall; and the method
includes inserting the ridge into the axial gap.
19. The method of claim 17, comprising receiving part of the gear
into a receptacle defined by the gear baffle.
20. The method of claim 17, comprising axially extending the
corrugation when attaching the second portion of the gear baffle to
the structure disposed to the second side of the gear.
Description
TECHNICAL FIELD
[0001] The disclosure relates generally to gas turbine engines, and
more particularly to gear baffles for interacting with lubricant
fluid around gears in gas turbine engines.
BACKGROUND
[0002] A gas turbine engine may include a gearbox for coupling one
of its spools to a load. The gearbox may include gears which may be
partially submerged in, or otherwise interacting with a lubricant
fluid. The interaction of the gear(s) with the lubricant fluid can
sometimes induce churning of the lubricant fluid. Such churning of
the lubricant fluid may be undesirable as it can cause drag-related
energy losses and aeration of the lubricant fluid which can reduce
the effectiveness of the lubricant fluid.
[0003] A gear baffle may be installed adjacent to a gear to
mitigate churning of the lubricant fluid caused by the rotation of
the gear. However, due to space constraints inside gearboxes of gas
turbine engines and dimensional variations in such gearboxes, the
design and installation of effective gear baffles in gearboxes of
gas turbine engines can be challenging.
SUMMARY
[0004] In one aspect, the disclosure describes a gear baffle for
interacting with a lubricant fluid around a gear in a gas turbine
engine. The gear baffle comprises:
[0005] a first interface for attaching the gear baffle to a
structure disposed to a first side of the gear;
[0006] a second interface for attaching the gear baffle to a
structure disposed to a second side of the gear opposite the first
side of the gear, the second interface being spaced apart from the
first interface by a distance; and
[0007] a main wall interconnecting the first interface with the
second interface, the main wall including a compliant corrugation
that accommodates a variation in the distance between the first
interface and the second interface.
[0008] In another aspect, the disclosure describes a gearbox of a
gas turbine engine. The gearbox comprises:
[0009] a housing;
[0010] a gear disposed inside the housing, the gear being rotatable
about an axis;
[0011] a baffle disposed inside the housing and adjacent the gear
to interact with lubricant fluid around the gear, the baffle
including:
[0012] a first interface for attaching the baffle relative to the
gear, the first interface being disposed to a first side of the
gear;
[0013] a second interface for attaching the baffle relative to the
gear, the second interface being disposed to a second side of the
gear axially opposite the first side of the gear relative to the
axis, the second interface being axially spaced apart from the
first interface by an axial distance; and
[0014] a main wall interconnecting the first interface with the
second interface, the main wall including an axially-compliant
corrugation that accommodates a variation in the axial distance
between the first interface and the second interface.
[0015] In a further aspect, the disclosure describes a method of
installing a gear baffle adjacent to a gear in a gearbox of a gas
turbine engine where the gear is rotatable about an axis. The
method comprises:
[0016] attaching a first portion of the gear baffle to a structure
disposed to a first side of the gear;
[0017] attaching a second portion of the gear baffle to a structure
disposed to a second side of the gear, the second portion being
axially spaced apart from the first portion by an axial distance
relative to the axis; and
[0018] accommodating a variation in the axial distance between the
first portion and the second portion by deforming an
axially-compliant corrugation formed into a main wall
interconnecting the first and second portions of the gear
baffle.
[0019] Further details of these and other aspects of the subject
matter of this application will be apparent from the detailed
description included below and the drawings.
DESCRIPTION OF THE DRAWINGS
[0020] Reference is now made to the accompanying drawings, in
which:
[0021] FIG. 1 shows a schematic axial cross-section view of an
exemplary turboprop gas turbine engine including a gearbox as
described herein;
[0022] FIG. 2 is a perspective schematic view of part of an
exemplary gearbox of the engine of FIG. 1 including a gear
baffle;
[0023] FIG. 3 is a schematic front view of the part of the gearbox
of FIG. 2
[0024] FIGS. 4-6 are perspective views of an exemplary gear baffle
for the gearbox of FIGS. 2 and 3;
[0025] FIG. 7 is a perspective front view of another exemplary gear
baffle for the gearbox of FIGS. 2 and 3;
[0026] FIG. 8 is a perspective front view of another exemplary gear
baffle for the gearbox of FIGS. 2 and 3;
[0027] FIG. 9 is a flowchart of an exemplary method of installing a
gear baffle; and
[0028] FIG. 10 is a cross-sectional view of the gear baffle of FIG.
3 with an associated main gear and neighbouring structure taken
along line 10-10 in FIG. 3.
DETAILED DESCRIPTION
[0029] The following disclosure describes gear baffles, gearboxes
including gear baffles, and methods for installing gear baffles. In
some embodiments, the gear baffles described herein may mitigate
churning of lubricant fluid while also accommodating space
constrains and dimensional variations between gearboxes of a same
type due in part to tolerance stack-up associated with the assembly
of components inside gearboxes. In some embodiments, the baffles
described herein may have a compliant (e.g., deformable) feature
(e.g., corrugation) that allows (e.g., non-destructive) deformation
of part of the baffles to accommodate such dimensional variations
in a controlled manner.
[0030] The terms "connected", "coupled" and "attached" may include
both direct connection/coupling/attachment (in which two elements
contact each other) and indirect connection/coupling/attachment (in
which at least one additional element is located between the two
elements). The terms "substantially" as used herein may be applied
to modify any quantitative representation which could permissibly
vary without resulting in a change in the basic function to which
it is related.
[0031] Aspects of various embodiments are described through
reference to the drawings.
[0032] FIG. 1 is a schematic axial cross-section view of an
exemplary reverse flow turboprop gas turbine engine 10 comprising
one or more gearboxes 12, as described herein. Even though the
following description and FIG. 1 specifically refers to a turboprop
gas turbine engine as an example, it is understood that aspects of
the present disclosure may be equally applicable to other types of
gearboxes and gas turbine engines including turboshaft and turbofan
gas turbine engines. Gas turbine engine 10 may be of a type
preferably provided for use in subsonic flight to drive a load such
as propeller 14 via gearbox 12 coupled to low-pressure shaft 16
(sometimes called "power shaft") further coupled to low-pressure
turbine 18.
[0033] Compressor 22 may draw ambient air into engine 10 via
annular radial air inlet duct 26, increase the pressure of the
drawn air and deliver the pressurized air to combustor 28 where the
pressurized air is mixed with fuel and ignited for generating an
annular stream of hot combustion gas. High-pressure turbine 20 may
extract energy from the hot expanding combustion gas and thereby
drive compressor 22. The hot combustion gas leaving high-pressure
turbine 20 may be accelerated as it further expands, flows through
and drives low pressure turbine 18. The combustion gas may then
exit gas turbine engine 10 via exhaust duct 30.
[0034] Low-pressure shaft 16 may be drivingly coupled to propeller
14 or another load via gearbox 12 and propeller shaft 32. Gearbox
12 may be of a speed-reducing type so that the rotation speed of
propeller shaft 32 may be lower than that of low-pressure shaft 16.
Engine 10 may have central axis CA, which may correspond to an axis
of rotation of one or more spools of engine 10. For example,
central axis CA may correspond to an axis of rotation of
low-pressure shaft 16. In various embodiments, central axis CA may
correspond to an axis of rotation of propeller shaft 32, or
propeller shaft 32 may rotate about an axis that is offset from
central axis CA.
[0035] FIG. 2 shows a perspective view of an exemplary gear set 34
that may be part of gearbox 12 and that may be disposed inside
housing 36 (shown schematically) of gearbox 12. Gear set 34 may be
only a subset of gears that are part of gearbox 12. Gear set 34 may
include main gears 38A, 38B and input gear 40 drivingly coupled to
(i.e., meshed with) both main gears 38A, 38B. Input gear 40 may be
coupled to low-pressure shaft 16 and receive an input torque from
low-pressure shaft 16. Input gear 40 may drive main gears 38A, 38B,
which may be drivingly coupled to propeller shaft 32 via other
gears that are not shown in FIG. 2. The relative sizes of input
gear 40 and of main gears 38A, 38B may provide a rotational speed
reduction.
[0036] In various embodiments, input gear 40 may be rotatable about
central axis CA of engine 10 or about an axis other than central
axis CA. Main gears 38A, 38B may be rotatable about respective
rotation axes RA1 and RA2. Axes RA1 and RA2 may be substantially
parallel to central axis CA. When being installed in housing 36,
main gears 38A, 38B and input gear 40 may be inserted as a
preassemble unit into housing 36 along arrow D. The preassembled
unit may include baffle 46 positioned adjacent to main gear 38A,
and optionally another gear baffle may be positioned adjacent to
main gear 38B.
[0037] In some embodiments, main gears 38A, 38B may each be a
double gear having two toothed faces 42A, 42B. For example, main
gears 38A, 38B may be double helical gears. For example, main gear
38A may have two toothed faces 42A that are axially spaced apart
and separated by axial gap 44A. Main gear 38B may also have two
toothed faces 42B that are axially spaced apart and separated by
axial gap 44B. Axial gaps 44A, 44B may be defined by respective
circumferential grooves extending around respective axes RA1, RA2
and that are radially-outwardly open. Input gear 40 may also have
two axially spaced apart toothed faces for meshing with counterpart
toothed faces 42A and 42B of main gears 38A, 38B.
[0038] FIG. 2 shows a single baffle 46 being installed adjacent to
main gear 38A for interacting with a liquid lubricant fluid 48
(e.g., oil) around main gear 38A. The geometric configuration of
baffle 46 may define a receptacle for receiving a lower portion of
main gear 38A that may be submerged in lubricant fluid 48. Baffle
46 may also include corrugation 50 that may optionally extend
radially-inwardly between toothed faces 42A and into axial gap 44A.
It is understood that another baffle could also be installed
adjacent to main gear 38B. Baffle 46 may be used in conjunction
with other gear types such as spur gears and/or with single gears
having only one toothed face instead of two. Baffle 46 may be used
in various types of gear sets including speed-reducing and
speed-augmenting types of gear sets.
[0039] FIG. 3 is a front plan view of an interior of gearbox 12
showing gear set 34 of FIG. 2. Gear baffle 46 may be attached to
fixed structure within gearbox 12 so that baffle 46 may be
stationary relative to rotating gear 38A. A first side of baffle 46
disposed to a first side of main gear 38A may be attached via one
or more first fasteners 52A (e.g., bolts, machine screws). A second
side of baffle 46 disposed to an axially opposite second side of
main gear 38A may be attached via one or more second fasteners 52B
(e.g., bolts, machine screws). First and second fasteners 52A, 52B
may be accessible from a same side of main gear 38A. For example,
second fasteners 52B may be accessible via one or more through
passages 54 formed in a web of main gear 38A. Through passages 54
may be positioned and sized allow for a tool such as socket or
other driver access to second fasteners 52B from the side of main
gear 38A shown in FIG. 2. Through passages 54 may be aligned with
second fastener(s) 52B by manually rotating main gear 38A during
installation or removal of baffle 46.
[0040] FIGS. 4 to 6 are perspective views of baffle 46. In
reference to FIGS. 4 and 5, baffle 46 may include first sidewall
56A and second sidewall 56B attached to main wall 58. First and
second sidewalls 56A, 56B may be axially spaced apart by axial
distance W. Main wall 58 may axially interconnect first and second
sidewalls 56A, 56B. Main wall 58 may be disposed radially outward
of main gear 38A. A gap may be provided between main gear 38A and
main wall 58, and also between main gear 38A and sidewalls 56A, 56B
to allow the presence and flow of lubricant fluid 48 between gear
faces 42A and baffle 46. First and second sidewalls 56A, 56B may
extend radially-inwardly from main wall 58 relative to rotation
axis RA1 of main gear 38A. When installed, first sidewall 56A may
be disposed to the first axial side of main gear 38A and second
sidewall 56B may be disposed to the opposite second axial side of
main gear 38A. In other words, baffle 46 may define receptacle 60
in which part of main gear 38A may be received during use.
[0041] First sidewall 56A may include one or more first interfaces
62A disposed thereon to permit the attachment of baffle 46 to a
structure within gearbox 12 to one axial side of main gear 38A.
Second sidewall 62B may include one or more second interfaces 62B
disposed thereon to permit the attachment of baffle 46 to a
structure within gearbox 12 to another axially opposite side of
main gear 38A. First interfaces 62A may each include a through
threaded hole for engagement with a threaded first fastener 52A
shown in FIG. 3. Such threaded holes may be drilled and tapped in
first sidewall 56A. In some embodiments, first interfaces 62A may
each include a self-locking helical coil (i.e., threaded) insert.
Second interfaces 62B may each include a through unthreaded hole
for receiving therethrough a threaded second fastener 52B shown in
FIG. 3. In some embodiments, the threaded holes of first interfaces
62A and the unthreaded holes of second interfaces 62B may be
oriented to be substantially parallel to rotation axis RA1.
[0042] First sidewall 56A and second sidewall 56B may be relatively
rigid and substantially planar. Baffle 46 may be made from a
suitable metallic material such as (e.g., stainless) steel. In some
embodiments, baffle 46 may be made from stamped sheet metal. First
sidewall 56A and second sidewall 56B may be interconnected by main
wall 58. Main wall 58 may include corrugation 50 (e.g., wrinkle,
fold, furrow, ridge) that may accommodate a dimensional variation
in axial distance W between first interface(s) 62A and second
interface(s) 62B. Corrugation 50 may be compliant (e.g.,
deformable) and may relatively easily absorb some dimensional
variation to facilitate installation of baffle 46. Corrugation 50
may compensate for dimensional variations caused by dimensional
tolerance stack-up associated with the structure(s) to which baffle
46 is attached. In some embodiments, corrugation 50 may permit
axial distance W to be extended and/or shortened within prescribed
amounts by the extension and/or compression of corrugation 50.
Corrugation 50 may be (e.g., resiliently and/or plastically)
deformable in a non-destructive manner.
[0043] First sidewall 56A and second sidewall 56B may be transverse
(e.g., substantially perpendicular) to main wall 58 and
substantially parallel to one another so that baffle 46 may define
a substantially U-shaped receptacle 60. Nominal axial dimension W
of baffle 46 (i.e., before deformation of corrugation 50) may be
determined based on an expected axial gear width of main gear 38A
and an expected axial distance between structure(s) to which first
and second sidewalls 56A, 56B of baffle 46 will be attached.
[0044] Main wall 58 may include radially-inner side 58A (surface)
facing main gear 38A, and a radially-outer side 58B (surface)
opposite radially-inner side 58A. Main wall 58 may have a curved
(e.g., arcuate) shape extending partially around axis RA1. In some
embodiments, corrugation 50 may define a ridge extending (e.g.,
radially-inwardly) from radially-inner side 58A of main wall 58. In
some embodiments, corrugation 50 may define groove 66 on
radially-outer side 58B of main wall 58. In some embodiments,
corrugation 50 may extend in a circumferential direction relative
to rotation axis RA1 of main gear 38A. Corrugation 50 may extend
the full arcuate/circumferential length of main wall 58. In some
embodiments, corrugation 50 may also provide added stiffness to
main wall 58.
[0045] In some embodiments, corrugation 50 may be disposed
substantially axially midway (e.g., at or close to W/2) between
first interface 62A and second interface 62B. In some embodiments,
corrugation 50 may be disposed to be axially coincident with axial
gap 44A (shown in FIG. 2) of main gear 38A so that corrugation 50
may extend radially into and occupy part of axial gap 44A during
operation. In some embodiments, main wall 58 may be perforated to
permit the flow of lubricant fluid 48 therethrough. Accordingly,
main wall 58 may have one or more perforations 68 of circular or
other cross-sectional shapes.
[0046] In some embodiments, main wall 58 may have two or more
corrugations 50. In some embodiments, main wall 58 may have one or
more corrugations that define one or more ridges extending (e.g.,
radially-outwardly) from radially-outer side 58B of main wall 58
for example. In various embodiments, an axial cross-sectional
profile of corrugation 50 in a plane parallel to rotation axis RA1
may be of any suitable shape such as sinusoidal, trapezoidal or saw
tooth shape for example.
[0047] In reference to FIG. 6, baffle 46 may be integrally formed
(e.g., stamped) from a piece of sheet metal of uniform thickness as
a single piece having a unitary construction. For example, as shown
in FIG. 6, a portion of main wall 58 at corrugation 50 may have a
wall thickness T1, and a portion of main wall 58 outside of
corrugation 50 may have a wall thickness T2. In some embodiments,
wall thickness T1 may be smaller than wall thickness T2. First and
second side walls 56A, 56B may have respective wall thicknesses T3
and T4. In some embodiments, wall thicknesses T3 and T4 may be
substantially equal. In some embodiments, wall thicknesses T3 and
T4 may be substantially equal to wall thickness T2 of main wall 58.
In some embodiments wall thickness T1 may be smaller than wall
thicknesses T2, T3 and T4. The smaller wall thickness T1 and/or
shape of corrugation 50 may encourage axial deformation of baffle
46 to be absorbed by corrugation 50 as opposed to other parts of
baffle 46. In other words, corrugation 50 may provide control over
the axial deformation of baffle 46. Such control over the
deformation of baffle 46 may also help maintain clearances between
baffle 46 and main gear 38A, and/or between baffle 46 and other
components of gearbox 12 despite dimensional variations.
[0048] FIG. 7 is a perspective front view of another exemplary gear
baffle 146 for use in gearbox 12. Baffle 146 may have elements in
common with baffle 46 already described above. Like elements have
been identified using reference numerals incremented by 100. Baffle
146 may include main wall 158 with corrugation 150 and perforations
168, first sidewall 156A with one or more first interfaces 162A,
and second sidewall 156B with one or more second interfaces 162B.
Baffle 146 may define receptacle 160 for receiving part of main
gear 38A.
[0049] Baffle 146 may be made from separate pieces that are
subsequently attached together. For example, sidewalls 156A, 156B
and main wall 158 may be made separately by any suitable metal
fabrication method(s) including machining and/or sheet metal
forming method(s), and then welded together at welded junctions 170
for example.
[0050] In some embodiments, wall thickness T1 of main wall 158 at
corrugation 150 may be substantially equal to or smaller than wall
thickness T2 of main wall 158 outside of corrugation 150. In some
embodiments, wall thicknesses T3 and T4 of first and second
sidewalls 156A, 156B may be substantially equal. In some
embodiments, wall thicknesses T3 and T4 may be greater than wall
thicknesses T1 and T2 of main wall 158. The smaller wall thickness
T1 and/or shape of corrugation 150 may encourage axial deformation
of baffle 46 to be absorbed by corrugation 150 as opposed to
bending of sidewalls 156A, 156B for example.
[0051] FIG. 8 is a perspective front view of another exemplary gear
baffle 246 for use in gearbox 12. Baffle 246 may have elements in
common with baffle 46 already described above. Like elements have
been identified using reference numerals incremented by 200. Baffle
246 may include main wall 256 with corrugation 250 and perforations
268, first sidewall 256A with one or more first interfaces 262A,
and second sidewall 256B with one or more second interfaces 262B.
Baffle 246 may define receptacle 260 for receiving part of main
gear 38A.
[0052] Baffle 246 may be machined (e.g., using a ball end mill) as
a single piece having a unitary construction from a block of
metallic material. In some embodiments, wall thickness T1 of main
wall 258 at corrugation 250 may be substantially equal to or
smaller than wall thickness T2 of main wall 258 outside of
corrugation 250. In some embodiments, wall thicknesses T3 and T4 of
first and second sidewalls 256A, 256B may be substantially equal.
In some embodiments, wall thicknesses T3 and T4 may be greater than
wall thicknesses T1 and T2 of main wall 258. The smaller wall
thickness T1 and/or shape of corrugation 250 may encourage axial
deformation of baffle 246 to be absorbed by corrugation 250 as
opposed to bending of sidewalls 156A, 156B for example.
[0053] FIG. 9 is a flowchart of an exemplary method 1000 of
installing a gear baffle adjacent to a gear in a gearbox of a gas
turbine engine. Method 1000 may be performed using any of gear
baffles 46, 146 or 246 in gearbox 12 described herein, or with
other baffles and gearboxes. It is understood that aspects of
method 1000 may be combined with other aspects or steps described
herein. Method 1000 may include:
[0054] attaching a first portion (e.g., first sidewall 56A) of
baffle 46 to a structure disposed to a first side of main gear 38A
(block 1002);
[0055] attaching a second portion (e.g., second sidewall 56B) of
baffle 46 to a structure disposed to a second side of main gear
38A, the second portion being axially spaced apart from the first
portion by axial distance W relative to rotation axis RA1 of main
gear 38A (block 1004); and
[0056] accommodating a variation in the axial distance W between
the first portion and the second portion by deforming
axially-compliant corrugation 50 formed into main wall 58
interconnecting the first and second portions of baffle 46 (block
1006).
[0057] FIG. 10 is a cross sectional view of baffle 46 and main gear
38A with neighbouring components taken along line 10-10 in FIG. 3.
Aspects of method 1000 are further described below in relation to
FIG. 10. Second sidewall 56B of baffle 46 may be attached to second
structure 72B via fastener(s) 52B extending through second sidewall
56B at respective second interface(s) 62B. Fasteners 52B may be
threadably engaged with threaded holes formed in second structure
72B. Fasteners 52B may be driven into second structure 72B using a
suitable tool extended through passage 54.
[0058] Second structure 72B may be any suitable structural element
stationary relative to main gear 38A. In some embodiments, second
structure 72B may be attached to or part (e.g., wall, web, boss,
cover) of housing 36 of gearbox 12. In some embodiments, main gear
38A may be rotatably supported by second structure 72B via one or
more bearings 74.
[0059] First sidewall 56A of baffle 46 may be attached to first
structure 72A via fastener(s) 52A extending through first sidewall
56A at respective first interface(s) 62A. Fasteners 52A may extend
through a (e.g., unthreaded) hole formed in first structure 72A and
be threadably engaged with threaded holes formed in first sidewall
56A at respective first interfaces 62A. Fasteners 52A may be driven
into first side wall 56A using a suitable tool. Fasteners 52A and
52B may be driven in the same direction and from a same axial side
of main gear 38A.
[0060] First structure 72A may be any suitable structural element
stationary relative to main gear 38A. In some embodiments, first
structure 72A may be attached to or part (e.g., wall, web, boss,
removable cover) of housing 36 of gearbox 12.
[0061] When baffle 46 is installed adjacent of main gear 38A, a
lower portion of main gear 36A may be received in receptacle 60
defined by baffle 46. Corrugation 50 may be axially positioned to
be in axial alignment with axial gap 44A of main gear 38A.
Corrugation 50 may also extend radially-inwardly and be inserted
into axial gap 44A to provide an efficient use of space within
gearbox 12 and also provide a beneficial interaction with the
lubricant fluid 48.
[0062] In various embodiments, the installation of baffle 46 may
include attaching second sidewall 56B to second structure 72B using
second fasteners 52B before or after attaching first sidewall 56A
to first structure 72A using first fasteners 52A. As an example, in
situations where baffle 46 is slightly axially undersized compared
to the axial distance between first and second structures 72A, 72B,
the tightening of first fasteners 52A after second fasteners 52B
have already been tightened may apply an axial tension force into
baffle 46 and cause an axial extension of baffle 46. The axial
extension is illustrated by arrow .DELTA.W in FIG. 10 and may be
accommodated by an axial deformation/extension of corrugation 50 of
main wall 58. On the other hand, in situations where baffle 46 is
slightly axially oversized compared to the axial distance between
first and second structures 72A, 72B, the positioning of baffle 46
between first and second structures 72A, 72B may require manual
axial shortening/compression of baffle 46. The axial
shortening/compression may be accommodated by an axial
deformation/compression of corrugation 50. In other words,
corrugation 50 may permit baffle 46 to be axially self-adjusting to
dimensional variations in gearboxes.
[0063] The embodiments described in this document provide
non-limiting examples of possible implementations of the present
technology. Upon review of the present disclosure, a person of
ordinary skill in the art will recognize that changes may be made
to the embodiments described herein without departing from the
scope of the present technology. Yet further modifications could be
implemented by a person of ordinary skill in the art in view of the
present disclosure, which modifications would be within the scope
of the present technology.
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