U.S. patent application number 15/864569 was filed with the patent office on 2018-05-24 for bearing faces with fluid channels for gear pumps.
The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Lubomir A. Ribarov, Leo J. Veilleux, JR..
Application Number | 20180142685 15/864569 |
Document ID | / |
Family ID | 55534728 |
Filed Date | 2018-05-24 |
United States Patent
Application |
20180142685 |
Kind Code |
A1 |
Veilleux, JR.; Leo J. ; et
al. |
May 24, 2018 |
BEARING FACES WITH FLUID CHANNELS FOR GEAR PUMPS
Abstract
A bearing carrier has a bearing body including a first material.
The bearing body has an exterior surface defining a bridge land
with a finger cut and rotatably supports a first and second gear.
The first and second gears intermesh with one another for
pressurizing fluid traversing the gears between a fluid inlet and a
fluid outlet defined in a housing enveloping the bearing carrier.
The bridge land is defined in a second material integral with the
first material. Methods fabricating a bearing carrier for a gear
pump are also disclosed.
Inventors: |
Veilleux, JR.; Leo J.;
(Wethersfield, CT) ; Ribarov; Lubomir A.; (West
Hartford, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Family ID: |
55534728 |
Appl. No.: |
15/864569 |
Filed: |
January 8, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14601511 |
Jan 21, 2015 |
9874208 |
|
|
15864569 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2230/91 20130101;
F05C 2201/0484 20130101; F16C 35/02 20130101; F16C 2220/24
20130101; F16C 33/14 20130101; F16C 17/04 20130101; F05C 2201/0448
20130101; F05C 2201/0475 20130101; F04C 2/18 20130101; B23K 26/34
20130101; F05C 2201/0412 20130101; F04C 2240/56 20130101; F16C
2237/00 20130101 |
International
Class: |
F04C 2/18 20060101
F04C002/18; F16C 33/14 20060101 F16C033/14; B23K 26/34 20140101
B23K026/34 |
Claims
1. A method of fabricating a bearing carrier, comprising: defining
a near net shape contour of a bridge land in a surface of a second
material integral with an underlying first material.
2. A method as recited in claim 1, further including coupling the
second material to the first material using a laser cladding
process.
3. A method as recited in claim 2, further including scanning a
surface of the first material prior to coupling the second material
to the first material using the laser cladding process.
4. A method as recited in claim 1, further including removing a
portion of the first material prior to coupling the second material
to the first material using the laser cladding process.
5. A method of fabricating a bearing carrier, comprising: at a
bearing body formed from a first material, the bearing body having
a bridge land with a finger cut to channel fluid pressurized by
intermeshing of gears rotatably supported by the bearing carrier
into an outlet defined by a housing enveloping the bearing carrier,
coupling a second material to the first material; and defining a
near-net shape contour of a bridge land in a surface of a second
material integral with an underlying first material.
6. The method as recited in claim 5, wherein the bearing body is a
cast body.
7. The method as recited in claim 5, wherein the bearing body is
formed from a copper alloy, brass, or bronze.
8. The method as recited in claim 5, wherein coupling the second
material to the first material includes coupling a second material
that is the same as the first material.
9. The method as recited in claim 5, wherein coupling the second
material to the first material includes coupling a second material
that is different than the first material.
10. The method as recited in claim 5, wherein coupling the second
material to the first material includes cladding the second
material to the first material.
11. The method as recited in claim 5, wherein coupling the second
material to the first material includes coupling a monel, steel, or
titanium second material to the first material.
12. The method as recited in claim 5, further comprising scanning
the bearing body to determine how much of the first material need
be removed from the bearing carrier prior to coupling the second
material to the first material.
13. The method as recited in claim 12, further comprising removing
a predetermined amount of first material from the bearing body
prior to coupling the second material to the first material.
14. The method as recited in claim 13, further comprising scanning
the bearing body to determine how much additional first material
need be removed from the bearing carrier prior to coupling the
second material to the first material
15. The method as recited in claim 5, further comprising removing a
predetermined amount of first material from the bearing body prior
to coupling the second material to the first material.
16. The method as recited in claim 15, wherein the removing a
predetermined amount of first material includes removing a portion
of the first material defining the bridge land.
17. The method as recited in claim 15, wherein removing a
predetermined amount of first material includes exposing a native
portion of the first material.
18. The method as recited in claim 5, further comprising defining a
bridge land contour in the second material.
19. A method of fabricating a bearing carrier, comprising: at a
bearing body formed from a first material, the bearing body having
a bridge land with a finger cut to channel fluid pressurized by
intermeshing of gears rotatably supported by the bearing carrier
into an outlet defined by a housing enveloping the bearing carrier,
scanning the bridge land of the bearing body; removing a portion of
the first material defining the bridge land; coupling a second
material to the first material; and defining a near-net shape
contour of a bridge land in a surface of a second material integral
with an underlying first material.
20. The method as recited in claim 19, further comprising eroding
the bridge land through cavitation in fluid traversing the bridge
land prior to scanning the bridge land.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of co-pending U.S.
application Ser. No. 14/601,511, filed Jan. 21, 2015, the contents
of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present disclosure relates to fluid pumping, and more
particularly to fluid pumping devices for gas turbine engines.
2. Description of Related Art
[0003] Pumps are commonly used to pump and pressurize fluid in
fluid distribution systems. Gas turbine engines, such as gas
turbine engines for aircraft main engines or auxiliary power units,
typically use gear pumps to provide fuel flow and pressure to gas
turbine engines and other aircraft systems. Such pumps generally
operate over a relatively large rotational speed operating range to
provide critical fuel flow and pressures for various functions. One
example of a fuel gear pump is a dual stage pump including a drive
gear and a driven gear. The drive gear is typically fixed to a
drive shaft, which receives rotational power from an accessory
gearbox. The driven gear is generally intermeshed with the drive
gear such that the teeth of the drive gear intermesh with the teeth
of the driven. Each stage of the gear pump is disposed within a
housing with an inlet and outlet and is supported by bearings with
a bearing face. The bearing face provides a contour that receives
pressurized fuel from the intermeshed gears and directs the
pressurize fuel to the housing outlet, and to maintain proper
function, pump assemblies including bearing surfaces can be
periodically replaced.
[0004] Such conventional methods and systems have generally been
considered satisfactory for their intended purpose. However, there
is a need in the art for improved gear pumps and methods of
reconditioning the bearing faces of such gear pumps. The present
disclosure provides a solution to these needs.
SUMMARY OF THE INVENTION
[0005] A bearing carrier has a bearing body including a first
material. The bearing body has an exterior surface defining a
bridge land with a finger cut and rotatably supports a first and
second gear. The first and second gears intermesh with one another
for pressurizing fluid traversing the gears between a fluid inlet
and a fluid outlet defined in a housing enveloping the bearing
carrier. The bridge land is defined in a second material integral
with the first material.
[0006] In certain embodiments the second material can be different
material than the first material. The second material can have
different physical properties than the first material. Wear
characteristics of the second material can be better than wear
characteristics of the first material. For example, the second
material can have a greater ultimate stress or yield stress than
the first material. Alternatively (or additionally), the second
material can have a greater thermal coefficient of expansion or
melting point than the first material. The second material can have
a density that is greater than or less than the density of the
first material. It is also contemplated that the galvanic potential
of the first material can be similar to the galvanic potential of
the second material, such as within about 0 to 0.4 volts of one
another.
[0007] In accordance with certain embodiments the second material
can be cladded to the first material, such as through a laser
cladding process. The first material can include a copper alloy,
e.g. brass or bronze, and the second material can include monel,
steel, aluminum bronze, nickel aluminum bronze, or titanium by way
of non-limiting example. Examples of suitable steels include
stainless steel, carbon steel, or any suitable steel alloy. In
certain embodiments, the second material has substantially the same
density and thermal coefficient of expansion as the first material,
and has superior mechanical properties including erosion
resistance.
[0008] It is also contemplated that in certain embodiments the
bearing body can have a `figure 8` shape, and the bridge land can
be disposed in the center of the `figure 8`. The bearing body can
define first and second shaft-receiving apertures, and the bridge
land can be defined between the shaft-receiving apertures. The
bearing body can be one of two bearing bodies incorporated into a
gear pump assembly housing, a first shaft being rotatably supported
in a first shaft aperture of each bearing body and a second shaft
being rotatably supported in a second shaft aperture of each
bearing body. A first gear can be mounted to the first shaft, and a
second gear can be mounted to the second shaft such that rotation
of the first and second gears drive fluid across the bridge land
surfaces of the first and second bearing bodies.
[0009] A method of fabricating a bearing carrier as described above
includes defining a near-net shape bridge land contour in the
bearing carrier. The bearing carrier includes a second material
coupled to a first material, and the near-net shape bridge land
contour is defined in the second material.
[0010] In embodiments, the second material is integrally coupled to
the first material using a laser cladding process. The method can
also include removing a portion of the first material prior to
adding material by coupling, e.g. depositing, the second material
over the first material with the laser cladding process. Prior to
removing the portion of the first material, the first material
surface can be scanned to determine the amount of the first
material to be removed. The first material surface can also be
scanned prior to adding the second material to the first material
to determine the amount material to be added using the laser
cladding process.
[0011] These and other features of the systems and methods of the
subject disclosure will become more readily apparent to those
skilled in the art from the following detailed description of the
preferred embodiments taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] So that those skilled in the art to which the subject
disclosure appertains will readily understand how to make and use
the devices and methods of the subject disclosure without undue
experimentation, preferred embodiments thereof will be described in
detail herein below with reference to certain figures, wherein:
[0013] FIG. 1 is a schematic view of an exemplary embodiment of a
fluid distribution system constructed in accordance with the
present disclosure, showing a gear pump;
[0014] FIG. 2 is a perspective view of the gear pump of FIG. 1,
showing the pump housing, inlet and outlet;
[0015] FIG. 3 is a perspective view of the gear pump of FIG. 1,
showing opposed bearing carriers having seated therein first and
second shafts with respective drive and driven gears;
[0016] FIG. 4 is an end view of one of the bearing carriers of the
gear pump of FIG. 1, showing shaft apertures and a bridge land
defined by the exterior surface of the bearing carrier;
[0017] FIG. 5 is an end view of another of the bearing carriers of
the gear pump of FIG. 1, showing shaft apertures and a bridge land
defined by the exterior surface of the bearing carrier;
[0018] FIG. 6 is a perspective view of a portion of the bearing
carrier of the gear pump of FIG. 1, showing a first material, a
second material, and the bridge land defined in the second
material; and
[0019] FIG. 7 is a diagram of a method of making a bearing carrier,
showing operations of the method, according to embodiments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Reference will now be made to the drawings wherein like
reference numerals identify similar structural features or aspects
of the subject disclosure. For purposes of explanation and
illustration, and not limitation, a partial view of an exemplary
embodiment of a gear pump in accordance with the disclosure is
shown in FIG. 1 and is designated generally by reference character
100. Other embodiments of fuel gear pumps in accordance with the
disclosure, or aspects thereof, are provided in FIGS. 2-7, as will
be described. The systems and methods described herein can be used
in gas turbine engines, such as aircraft main engines or auxiliary
engines.
[0021] Gear pump 100 is operatively associated with a prime mover
12 of an aircraft 14 for pumping fluid through a fluid distribution
system 16 incorporated within aircraft 14. Prime mover 12 may be a
gas turbine engine, such as an aircraft main engine or auxiliary
power unit, and is operatively associated with gear pump 100
through an accessory gearbox drive shaft 18. Accessory gearbox
drive shaft 18 is connected to an accessory gearbox 20. Accessory
gearbox 20 is connected to gear pump 100 through a pump drive shaft
22. Gear pump 100 is operatively associated with fluid distribution
system for receiving input fluid at a first pressure and supplying
the input fluid at a second pressure, the second pressure being
greater than the first pressure. Fluid distribution system 16 may
be a fuel system, a hydraulic system, fueldraulic system,
lubrication system, or other suitable fluid distribution
system.
[0022] With reference to FIG. 2, an exterior of gear pump 100 is
shown. Gear pump 100 includes a housing 102. Housing 102 receives
an input shaft 104 and defines a fluid inlet 106 and a fluid outlet
108. Rotation of input shaft 104 drives drive and driven gears
(shown in FIG. 3) disposed within housing 102 such that fluid
entering fluid inlet 106 is pressurized and provided at fluid
outlet 108.
[0023] With reference to FIG. 3, an interior of gear pump 100 is
shown. Gear pump 100 includes a first stage 110 and a second stage
112 serially arranged in relation to one another along a first
rotation axis A and a second rotation axis B. First stage 110
includes a first bearing carrier 114, a second bearing carrier 116,
a first gear 120, and a second gear 118. First bearing carrier 114
defines a first shaft-receiving aperture 122 (shown in FIG. 4) and
a second shaft-receiving aperture 124 (shown in FIG. 4). First gear
120 is fixed to first shaft 130 and extends along rotation axis B
as an assembly. First shaft 130 is rotatably supported in both
first shaft-receiving aperture 122 and first shaft-receiving
aperture 126 (shown in FIG. 5). Second gear 118 is fixed to second
shaft 132 and extends along rotation axis A. Second shaft 132 is
rotatably supported in both second shaft-receiving aperture 124 and
second shaft-receiving aperture 128 (shown in FIG. 5) such that
second shaft 132 is parallel with first shaft 130 and teeth of
first gear 120 are intermeshed with teeth of second gear 118.
[0024] Input shaft 104 is coupled to second shaft 132 for rotating
second shaft 132. Rotation of second shaft 132 rotates second gear
118. As second gear 118 rotates, teeth of second gear 118 intermesh
and rotate with teeth of first gear 120. This pumps fluid disposed
between teeth of second gear 118, i.e. the drive gear, and first
gear 120, i.e. the driven gear, as described in U.S. patent
application Ser. No. 13/614,173, filed Sep. 13, 2014, the contents
of which are incorporated herein in their entirety.
[0025] With reference to FIG. 4, first bearing carrier 114 is
shown. First bearing carrier 114 is a cast body formed from a
copper alloy, such as brass, bronze or other suitable material, and
includes a first bearing body 140 and a second bearing body 142.
First bearing body 140 is adjacent to second bearing body 142 and
may be adjacent to one another or integrally joined to one another
in a structure having a `figure 8` axial profile, i.e. when viewed
along rotation axis A or rotation axis B. A bearing face 144 of
first bearing body 140 defines first shaft-receiving aperture 126
and mates to an axial end face of second bearing carrier 116 (shown
in FIG. 3). First shaft 130 is rotateably supported within first
shaft-receiving aperture 126. A bearing face 148 of second bearing
body 142 defines second shaft-receiving aperture 128 and mates to a
corresponding axial end of second bearing carrier 116 (shown in
FIG. 3). Second shaft 132 is rotateably supported with second
shaft-receiving aperture 128.
[0026] First bearing body 140 defines an edge 152 that is adjacent
to an edge 154 of second bearing body 142. Adjacent of edge 152 and
edge 154, both first bearing body 140 and second bearing body 142
define a bridge land 156 (circled in FIG. 4). Bridge land 156
includes an inlet channel 158 and an outlet channel 160 defined by
adjacent portions first bearing body 140 and second bearing body
142. A finger 162 of first bearing body 140 and a finger 168 of
second bearing body 142 separate inlet channel 158 from outlet
channel 160. As first gear 120 (shown in FIG. 3) and second gear
118 (shown in FIG. 3), fluid is drawn from inlet channel 158 at a
first pressure and into outlet channel 160 at a second pressure,
the second pressure being higher than the first pressure.
[0027] Bridge land 156 facilitates fluid interchange at the gear
mesh. Cavitation can occur when the local fluid pressure falls
below the true vapor pressure of the fluid, allowing fluid bubbles
to form and violently collapse back into solution. When cavitation
occurs on or near a solid surface, the high intensity collapse
force or cavitation damage power, similar to a shockwave, can cause
high surface stresses and lead to local deterioration of the
surface, potentially damaging the surface, such as through pitting.
Cumulative pitting can erode the surface contour of bridge land
156, changing fluid handling, and changing performance of the gear
pump. Pressure ripple, which is also caused by the fluid
interchange at the gear mesh, increases and decreases the local
fluid pressure, which can increase cavitation and may cause other
detrimental effects to the system.
[0028] With reference to FIG. 5, second bearing carrier 116 is
shown. Second bearing carrier 116 is similar to first bearing
carrier 114, and additionally includes a surface contour that
mirrors the surface contour of first bearing carrier 114. Second
bearing carrier 116 defines shaft-receiving apertures, a first
shaft-receiving aperture 126 of second bearing carrier 116 facing
first shaft-receiving aperture 122 (shown in FIG. 4) of first
bearing carrier 114, and a second shaft-receiving aperture 128 of
second bearing carrier 116 facing second shaft-receiving aperture
124 (shown in FIG. 4) of first bearing carrier 114.
[0029] With reference to FIG. 6, a portion of first bearing carrier
114 is shown. First bearing carrier 114 includes a first material
170 and second material 172. Second material 172 is integrally
coupled to first material 170 and defines bridge land 156, and may
be cladded to first material 170. First material 170 is a cast
copper alloy, such as brass or bronze. Second material 172 may also
be a copper alloy, and in certain embodiments includes the same
material as included in first material 170. The bridge land is
defined in a second material integral with the first material.
[0030] In embodiments, second material 172 may be a different
material from first material 170. For example, in certain
embodiments, second material has a greater ultimate stress or yield
stress than first material 170. Second material 172 may have a
greater thermal coefficient of expansion or melting point than
first material 170. A density of second material 172 can be greater
than or less than a density of first material 170. Examples of
materials included in second material 172 are aluminum and aluminum
alloys, monel, carbon or stainless steel, and titanium or titanium
alloy. It is noted that monel can provide substantially the same
coefficient of thermal expansion and density as the copper alloy
forming first material 170 while providing improved mechanical
stress. This can potentially render bridge land 156 more resistant
to cavitation damage and/or erosion from cavitation.
[0031] In accordance with certain embodiments the second material
can be cladded to the first material, such as through a laser
cladding process. The first material can include a copper alloy,
e.g. brass or bronze, and the second material can include monel,
steel, or titanium. The steel can be a stainless steel, carbon
steel, or other suitable steel alloy material. In an embodiment,
the second material has substantially the same density and thermal
coefficient of expansion as the first material, and has superior
mechanical properties including erosion resistance. It is
contemplated that second material 172 can have a galvanic potential
that is similar than a galvanic potential of first material 170,
e.g. the galvanic potential of second material 172 being within
about 0 to 0.4 volts of first material 170. This can reduce or
eliminate galvanic corrosion that could potentially develop between
first and second material under certain conditions.
[0032] With reference to FIG. 7, a method 200 of fabricating a
bearing carrier, e.g. first bearing carrier 114, is shown. Method
200 includes providing a bearing carrier with a surface defining a
bridge land, e.g. bridge land 156, formed from a first material,
e.g. first material 170, as shown with box 210. The first material
can be a copper alloy such as brass or bronze, and can be a cast
body, and can include native material from a new bearing carrier or
from a bearing carrier previously used in a pump assembly. Method
200 also includes scanning the bridge land, as shown with a box
220. The scanning process can provide information for determining
how much of the first material need be removed from the bearing
carrier. It can also be for purposes of determining how much of a
second material, e.g. second material 172, need be added to the
bearing carrier. As indicated with arrow 240, the scanning process
can be iterative.
[0033] Method 200 also includes removing a portion of the first
material defining the bridge land, as indicated by box 230. This
can expose a native portion of the first material that may more
readily integrate with the second material. Method 200 further
includes coupling a second material to the first material, as
indicated by a box 250. The coupling process may include a cladding
process, such as a laser cladding process, to form a near-net
shape. The near-net shape formed by the cladding process can
closely, though not necessarily precisely, resemble the intended
final contour of bridge land. Method 200 further includes defining
a bridge land contour in the second material, as shown by box 260.
This provides a fluid handing surface with the fluid handling
properties similar to the original copper alloy bridge land but
with the resistance to pitting and/or erosion that is
characteristic of the second material cladded to the first
material.
[0034] Although particular operation sequences are shown,
described, and claimed, it should be understood that operations may
be performed in any order, separated or combined unless otherwise
indicated and will still benefit from the present disclosure.
[0035] In embodiments, bearing carriers having a second material
integrally coupled to a first material can provide a robust,
relatively compact, lightweight additive insert to the bridge land
of the main drive gear bearings. In certain embodiments, fuel gear
pumps incorporating such bearing carriers can provide improved fuel
pump operability in aircraft fuel systems, operability, and safety.
It is also contemplate that, in embodiments, a second material
defining the bridge material and coupled to the first material, can
provide reduced cavitation and pressure ripple in the fuel system
over a range of operating speeds and fuel temperatures. This will
reduce deterioration of the gears, bearings, housings, and other
system components, thus maintaining pump and system performance and
increasing component operating life. The minimized pressure ripple
and cavitation damage power intensity will create a more stable
fuel system that can be more easily and accurately monitored and
controlled.
[0036] The methods and systems of the present disclosure, as
described above and shown in the drawings, provide for gear pumps
with superior properties including improved erosion resistance.
While the apparatus and methods of the subject disclosure have been
shown and described with reference to preferred embodiments, those
skilled in the art will readily appreciate that changes and/or
modifications may be made thereto without departing from the spirit
and scope of the subject disclosure.
* * * * *