U.S. patent application number 15/917562 was filed with the patent office on 2018-09-13 for pump gear.
The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Andrew P. Grosskopf, Craig J. Wojcik.
Application Number | 20180258795 15/917562 |
Document ID | / |
Family ID | 58190479 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180258795 |
Kind Code |
A1 |
Wojcik; Craig J. ; et
al. |
September 13, 2018 |
PUMP GEAR
Abstract
An integrated drive generator includes an input shaft and an
input drive gear connected to the input shaft. The integrated drive
generator also includes an input driven gear meshed with the input
drive gear. The integrated drive generator also includes a
hydraulic speed trimming device. The hydraulic speed trimming
device includes an input shaft connected to the input driven gear,
an output shaft, an accessory drive gear connected to the output
shaft, and an output ring gear connected to the output shaft. The
input driven gear, the accessory drive gear, and the output ring
gear are coaxial and disposed proximate a first end of the
hydraulic speed trimming device. The integrated drive generator
also includes a pump assembly with a pump drive shaft and a pump
gear connected to the pump drive shaft and meshed with the
accessory drive gear.
Inventors: |
Wojcik; Craig J.;
(Frankfort, IL) ; Grosskopf; Andrew P.; (Rockford,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Family ID: |
58190479 |
Appl. No.: |
15/917562 |
Filed: |
March 9, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14846210 |
Sep 4, 2015 |
|
|
|
15917562 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 15/08 20130101;
Y02T 50/671 20130101; F01D 25/20 20130101; Y02T 50/60 20130101;
F02C 7/32 20130101; F01D 15/12 20130101; F01D 15/10 20130101; F02C
7/275 20130101 |
International
Class: |
F01D 25/20 20060101
F01D025/20; F02C 7/32 20060101 F02C007/32; F02C 7/275 20060101
F02C007/275; F01D 15/08 20060101 F01D015/08; F01D 15/10 20060101
F01D015/10; F01D 15/12 20060101 F01D015/12 |
Claims
1. A pump gear for rotating a drive shaft of a pump assembly of an
integrated drive generator for a gas turbine engine, the pump gear
comprising: an outside diameter; and a pitch diameter, wherein a
ratio of the outside diameter and the pitch diameter is about 1.027
to about 1.029.
2. The pump gear of claim 1, wherein the pump gear further
comprises: a root diameter, wherein a ratio of the root diameter
and the pitch diameter is about 0.957 to about 0.962.
3. The pump gear of claim 2, wherein the pump gear further
comprises: a center hub, the center hub comprising: a hub outer
diameter; and a hub hole extending through a center of the hub
along a center axis of the pump gear, wherein a ratio of the hub
outer diameter and the outside diameter of the pump gear is about
0.242 and 0.251.
4. The pump gear of claim 3, wherein the hub hole includes a double
D cross-sectional profile with two flat sides and two rounded
sides, wherein the two flat sides define a hub hole width and the
two rounded sides define a hub hole diameter, and wherein a ratio
of the hub hole diameter and the hub outer diameter is about 0.622
to about 0.647.
5. The pump gear of claim 4, wherein the pump gear comprises at
least seventy teeth.
6. The pump gear of claim 5, wherein a ratio of an axial width of
the teeth and an axial width of the hub is about 0.532 to about
0.580.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a divisional of U.S. application Ser.
No. 14/846,210 filed Sep. 4, 2015 for "Pump Gear."
BACKGROUND
[0002] This disclosure is directed generally to an integrated drive
generator for use with an aircraft gas turbine engine, and more
specifically, to an oil pump assembly of an integrated drive
generator.
[0003] Integrated drive generators have been in use for many years
in generating electrical power on airframes. An integrated drive
generator functions to produce a constant three-phase 400 Hz
alternating current when driven by a variable speed gearbox located
on an airframe propulsion engine, generally a gas turbine engine.
The integrated drive generator is a single unit that includes a
hydraulic speed trimming device and an alternating current
generator mounted within a case assembly. The hydraulic speed
trimming device converts a variable speed shaft input from a
gearbox on a gas turbine engine to a constant speed shaft output to
drive the alternating current generator.
[0004] The integrated drive generator also generally includes a
scavenge pump, an inversion pump, and a charge pump disposed within
the case assembly of the integrated drive generator. The scavenge
pump draws oil from an oil sump located in the bottom of the case
and supplies the oil to a filter which removes various debris
within the oil prior to entering the cooling circuit located
external to the integrated drive generator on the aircraft. The
output of the deaerator, which contains oil of higher quality than
that pumped by the scavenge pump, is applied to the intake of the
charge pump. The charge pump pressurizes the oil and applies the
oil to an oil circuit. The oil circuit supplies oil to the
hydraulic speed trimming device, to the alternating current
generator for cooling and lubricating the alternating current
generator, to the casing of the integrated drive generator for
cooling, and to other components of the integrated drive generator
that require oil circulation for cooling and/or lubrication.
Generally, an assembly of gears is used to mechanically connect the
scavenge pump, the inversion pump, and charge pump to the output of
the hydraulic speed trimming device.
Should any part of the integrated drive generator require
maintenance or replacement, an operator generally must open the
case assembly and at least partially disassemble the integrated
drive generator. Reducing the complexity of the integrated drive
generator results in maintenance cost savings by reducing the
amount of parts to maintain within the integrated drive generator
and the amount of time required to disassemble and reassemble the
integrated drive generator. Reducing the complexity of the
integrated drive generator also results in manufacturing cost
savings by reducing the number of parts needed to produce the
integrated drive generator and the time required to assemble the
integrated drive generator.
SUMMARY
[0005] In one aspect of the invention, an integrated drive
generator includes an input shaft and an input drive gear connected
to the input shaft. The integrated drive generator also includes an
input driven gear meshed with the input drive gear. The integrated
drive generator also includes a hydraulic speed trimming device.
The hydraulic speed trimming device includes an input shaft
connected to the input driven gear, an output shaft, an accessory
drive gear connected to the output shaft, and an output ring gear
connected to the output shaft. The input driven gear, the accessory
drive gear, and the output ring gear are coaxial and disposed
proximate a first end of the hydraulic speed trimming device. The
integrated drive generator also includes a pump assembly with a
pump drive shaft and a pump gear connected to the pump drive shaft
and meshed with the accessory drive gear.
[0006] In another aspect of the invention, a pump gear for rotating
a drive shaft of a pump assembly of an integrated drive generator
for a gas turbine engine includes an outside diameter and a pitch
diameter. A ratio of the outside diameter and the pitch diameter is
about 1.027 to about 1.029.
[0007] Persons of ordinary skill in the art will recognize that
other aspects and embodiments of the present invention are possible
in view of the entirety of the present disclosure, including the
accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of an integrated drive
generator.
[0009] FIG. 2 is a perspective view of the integrated drive
generator of FIG. 1 with a housing assembly removed.
[0010] FIG. 3 is an exploded view of a pump assembly from the
integrated drive generator of FIG. 2.
[0011] FIG. 4 is a plan view of a pump gear from the pump assembly
of FIG. 3.
[0012] FIG. 5 is a cross-sectional view of the pump gear of FIG. 4
taken along line A-A.
[0013] FIG. 6 is a cross-sectional view of the pump gear teeth of
FIG. 5.
[0014] While the above-identified drawing figures set forth one or
more embodiments of the invention, other embodiments are also
contemplated. In all cases, this disclosure presents the invention
by way of representation and not limitation. It should be
understood that numerous other modifications and embodiments can be
devised by those skilled in the art, which fall within the scope
and spirit of the principles of the invention. The figures may not
be drawn to scale, and applications and embodiments of the present
invention may include features and components not specifically
shown in the drawings. Like reference numerals identify similar
structural elements.
DETAILED DESCRIPTION
[0015] The present disclosure provides an integrated drive
generator for use with a gas turbine engine. The integrated drive
generator includes a pump assembly with a pump cover and a pump
sleeve that house a charge pump, a scavenge pump, and an inversion
pump within the integrated drive generator. The pump cover and pump
sleeve simplify the assembly of the integrated drive generator by
congregating the charge pump, the scavenge pump, and the inversion
pump into a single unit that requires fewer attachment components
than prior art assemblies to connect the charge pump, the scavenge
pump, and the inversion pump within the integrated drive generator.
Furthermore, aligning the charge pump, the scavenge pump, and the
inversion pump within the pump sleeve and the pump cover provides
for fewer gears and other moving parts within the integrated drive
generator. Reducing the number of gears and other moving parts
within integrated drive generator increases the service life of
integrated drive generator by reducing the amount of internal
vibration and the wear and tear associated with internal
vibration.
[0016] FIGS. 1-2 will be discussed concurrently. FIG. 1 is a
perspective view of integrated drive generator (IDG) 10 with
housing assembly 12. As shown in FIG. 1, housing assembly 12 can
include input housing 14, center housing 16, and end housing 18.
FIG. 2 is a perspective view of IDG 10 of FIG. 1 with input housing
14 and center housing 16 of housing assembly 12 removed. In
addition to housing assembly 12, IDG 10 can also include variable
speed input shaft 20, oil outlet 22, oil inlet 24, generator 26,
hydraulic speed trimming device 28, input drive gear 30, input
driven gear 32, output ring gear 34, generator driven gear 36,
accessory drive gear 38, differential 40, and pump assembly 42.
Pump assembly 42 can include pump gear 44, pump cover 46, pump
drive shaft 47, pump sleeve 48, and pump interior components
49.
[0017] Generator 26, hydraulic speed trimming device 28, and pump
assembly 42 are all contained within housing assembly 12. As shown
in FIG. 1, housing assembly 12 is assembled around generator 26,
hydraulic speed trimming device 28 and pump assembly 42 by
connecting center housing 16 between input housing 14 and end
housing 18. Variable speed input shaft 20 extends across input
housing 14 and into the interior of IDG 10. An end of variable
speed input shaft 20, disposed outside of housing assembly 12,
interfaces with a gearbox on a gas turbine engine such that the
gearbox on the gas turbine engine rotates variable speed input
shaft 20 at a variable speed. Input drive gear 30 is disposed
within housing assembly 12 and is mechanically connected to
variable speed input shaft 20 such that variable speed input shaft
20 rotates input drive gear 30 at a variable speed. Input driven
gear 32 is disposed within housing assembly 12 and is meshed with
input drive gear 30 such that input drive gear 30 rotates input
driven gear 32 at a variable speed. As input drive gear 30 rotates
input driven gear 32, input driven gear 32 causes a rotation to
(not shown), internal to differential 40, which rotates a variable
coaxial shaft (not shown) of hydraulic speed trimming device 28 at
a variable speed. Hydraulic speed trimming device 28 uses the
variable input speed of the variable coaxial shaft (not shown) to
trim the variable speed which results in the fixed coaxial shaft 29
rotating to adjust the speed of a sun gear (not shown). The sun
gear (not shown) interacts with planet gears (not shown) mounted in
the carrier shaft to rotate the output ring gear at a constant
speed. Fixed coaxial shaft 29 is disposed around variable coaxial
shaft (not shown) such that fixed coaxial shaft 29 is coaxial with
variable coax shaft (not shown).
[0018] A mounting bracket 33 is attached to output ring gear 34.
Accessory drive gear 38 is connected to mounting bracket 33.
Hydraulic speed trimming device 28 in conjunction with the
differential 40 rotates the output ring gear 34, accessory drive
gear 38 and generator driven gear 36 at a constant speed. As shown
in FIG. 2, differential 40 can be disposed axially between output
ring gear 34 and input driven gear 32. Differential 40 can also
mechanically connect input driven gear 32 to variable coaxial shaft
(not shown) which is concentric with the fixed coaxial shaft 29.
Output ring gear 34 can be disposed between differential 40 and
accessory drive gear 38. Accessory drive gear 38, output ring gear
34, and input driven gear 32 can be coaxial and can all be disposed
on the same side or end of hydraulic speed trimming device 28.
Coaxially aligning accessory drive gear 38, output ring gear 34,
and input driven gear 32 within IDG 10 can help reduce the overall
size of IDG 10. Positioning accessory drive gear 38, output ring
gear 34, and input driven gear 32 on the same side or end of
hydraulic speed trimming device 28 reduces the total size of the
IDG 10 while ensuring the variable input speed is trimmed to output
a fixed speed for output ring gear 34. Should an operator need to
inspect or perform maintenance on accessory drive gear 38, output
ring gear 34, and input driven gear 32, the operator need only
remove a portion of housing assembly 12, such as input housing 14,
to access accessory drive gear 38, generator driven gear 36, and
input driven gear 32.
[0019] Generator driven gear 36 meshes with output ring gear 34
such that output ring gear 34 rotates generator driven gear 36 at a
constant speed. Generator driven gear 36 is connected to a rotor
(not shown) of generator 26 which rotates at a constant speed due
to the interaction of output ring gear 34 and generator driven gear
36. Generator 26 can be an alternating current electrical
generator.
[0020] Accessory drive gear 38 can mesh with pump gear 44 such that
accessory drive gear 38 rotates pump gear 44 at a constant speed.
Pump gear 44 is connected to pump drive shaft 47 such that pump
drive shaft 47 rotates in unison with pump gear 44. The rotation of
pump drive shaft 47 spins pump interior components 49 of pump
assembly 42 such that pump assembly 42 can circulate oil within IDG
10, out of IDG 10 through oil outlet 22, and back into IDG 10
through oil inlet 24. As discussed below with reference to FIGS.
3-6, pump sleeve 48 at least partially houses pump interior
components 49 of pump assembly 42 into a relatively compact unit
that is relatively simple to install inside housing assembly 12 of
IDG 10.
[0021] FIGS. 3-6 will be discussed concurrently. FIG. 3 is an
exploded view of pump assembly 42 along center axis CA of pump
assembly 42. As shown in FIG. 3, pump gear 44, pump cover 46, pump
sleeve 48, and pump interior components 49 all share center axis
CA. FIG. 4 is a plan view of pump gear 44 from pump assembly 42 of
FIG. 3. FIG. 5 is a cross-sectional view of pump gear 44 taken
along line A-A in FIG. 4. FIG. 6 is a cross-sectional view of pump
gear teeth 70. As shown in FIG. 3, pump sleeve 48 can include
tubular body 50. Tubular body 50 can include first end 52, second
end 54, outside surface 56, inside surface 58, and center axis CA.
First end 52 of tubular body 50 can include mounting flange 59 to
help connect the entire pump assembly 42 to IDG 10. As shown in
FIGS. 3-6, pump gear 44 can include rim 60 with teeth 70
(represented by three dashed lines--outside diameter D.sub.1, pitch
diameter D.sub.2, and root diameter D.sub.3), center hub 62,
webbing 64, a plurality of holes 66, spokes 68, outside diameter
D.sub.1, pitch diameter D.sub.2, and root diameter D.sub.3. Teeth
70 can include teeth axial width W.sub.1. Center hub 62 can include
hub outer diameter D.sub.4, hub first side 72, hub second side 74,
hub axial width W.sub.2, hub center hole 76, and slot 78. Hub
center hole 76 can include flat sides 79, round sides 80, hub hole
width W.sub.3, hub hole diameter D.sub.5, and expanded region 81.
Pump interior components 49, shown in FIG. 3, can include charge
pump 82, scavenge pump 84, and inversion pump 86.
[0022] Tubular body 50 extends from first end 52 to second end 54
along center axis CA. Center axis CA can be the center axis for
tubular body 50, pump sleeve 48, pump cover 46, pump gear 44, and
the rest pump assembly 42. Pump sleeve 48 can be formed from metal
material, such as steel, titanium, aluminum, alloys, super alloys,
and/or other various types of metals. First end 52 of tubular body
50 can be open so that charge pump 82, scavenge pump 84, and
inversion pump 86 can be inserted into pump sleeve 48 to form a
stack of pumps inside pump sleeve 48.
[0023] Each of charge pump 82, scavenge pump 84, and inversion pump
86 can individually be a rotary vane pump. When pump interior
components 49 are assembled within pump sleeve 48, as shown in FIG.
3, inversion pump 86 is disposed axially between scavenge pump 84
and charge pump 82, with scavenge pump 84 disposed proximate second
end 54 of tubular body 50 and charge pump 82 disposed proximate
first end 52 of tubular body 50.
[0024] Pump cover 46 is removably connected to mounting flange 59
on first end 52 of tubular body 50 to retain charge pump 82,
scavenge pump 84, and inversion pump 86 within pump sleeve 48.
Keeping charge pump 82, scavenge pump 84, and inversion pump 86
retained and tightly stacked within pump sleeve 48 helps reduce
vibration, wear, and fluid flow inefficiency of pump assembly 42.
Mounting flange 59 and pump cover 46 can be used to connect pump
assembly 42 to interior walls (not shown) formed on center housing
16 of housing assembly 12 (shown in FIG. 1).
[0025] Pump drive shaft 47 is connected to charge pump section 82,
scavenge pump 84, and inversion pump 86 and can extend through pump
cover 46 to connect with pump gear 44. During operation, pump gear
44 delivers torque to pump drive shaft 47 from accessory drive gear
38 (shown in FIG. 2) to rotate the vanes of charge pump 82,
scavenge pump 84, and inversion pump 86 at a constant speed.
[0026] As shown in FIGS. 3-5, pump gear 44 can be a spur gear. Rim
60 of pump gear 44 is positioned radially outward from center hub
62, and webbing 64 can extend between rim 60 and center hub 62. The
plurality of holes 66, which can be six in number as shown in FIGS.
3-4, can be formed in webbing 64 to reduce the weight of pump gear
44 and to form spokes 68 between rim 60 and center hub 62. The
plurality of holes 66 and spokes 68 can be distributed around
center axis CA so as to balance the weight of pump gear 44 about
center axis CA and prevent pump gear 44 from resonating or
vibrating during operation. Pump gear 44 can be formed from metal
material, such as steel, titanium, alloys, super alloys, and/or
other various types of metals.
[0027] Hub center hole 76 extends through the center of hub 62
along center axis CA of pump gear 44, as shown best in FIGS. 4 and
5. Hub center hole 76 can include a double D cross-sectional
profile with two flat sides 79 and two rounded sides 80. Flat sides
79 can be disposed radially across from one another. Hub hole width
W.sub.3 represents the distance between flat sides 79. Rounded
sides 80 can be disposed radially across from one another and hub
hole diameter D.sub.5 can represent the distance between rounded
sides 80. Pump drive shaft 47 (shown in FIG. 3), can also include a
double D cross-sectional profile that corresponds with flat sides
79 and rounded sides 80 of hub center hole 76, thereby allowing
pump drive shaft 47 to mesh with pump gear 44. When pump gear 44 is
assembled onto pump drive shaft 47, the double D cross-sectional
profile of drive shaft 47 and hub center hole 76, along with a
fastener (not shown) and keyed washer (not shown), will help
prevent pump gear 44 from slipping while, at the same time,
allowing pump drive shaft 47 to rotate such that pump gear 44 can
transfer torque to pump drive shaft 47. Slot 78 can be formed in
hub 62 proximate one of rounded sides 80 of center hole 76 and can
be configured to receive a keyed washer (not shown) secured by a
fastener (not shown) for connecting pump gear 44 to pump drive
shaft 47.
[0028] Pump gear 44 can be sized and optimized to maximize the
efficiency of pump assembly 42. Shown best in FIG. 6, outside
diameter D.sub.1, pitch diameter D.sub.2, and root diameter D.sub.3
of pump gear 44 are some of the dimensions of pump gear 44 that can
be sized to maximize the performance of pump assembly 42 and the
overall performance of IDG 10. Outside diameter D.sub.1 of pump
gear 44 can be defined as the diameter of the circle that contains
the tops of teeth 70 of pump gear 44. Pitch diameter D.sub.2 can be
defined as the diametral position on pump gear 44 where the
circular tooth thickness, pressure angle and helix angles of teeth
70 are defined. Root diameter D.sub.3 can be defined as the
diameter of gear 44 measured at the base of teeth 70, or in other
words, twice the distance between center axis CA and the base of
teeth 70. A ratio (D.sub.1/D.sub.2) of outside diameter D.sub.1 and
pitch diameter D.sub.2 can be about 1.027 to about 1.029.
Optimizing the ratio (D.sub.1/D.sub.2) of outside diameter D.sub.1
and pitch diameter D.sub.2 ensures that pump gear 44 is large
enough to bridge the space between pump drive shaft 47 and
accessory drive gear 38 (shown in FIG. 2) while still providing
sufficient space to accommodate teeth 70 of pump gear 44. A ratio
(D.sub.3/D.sub.2) of root diameter D.sub.3 and pitch diameter
D.sub.2 can be about 0.957 to about 0.962. Optimizing the ratio
(D.sub.3/D.sub.2) of root diameter D.sub.3 and pitch diameter
D.sub.2 further defines the space needed to accommodate teeth 70 on
pump gear 44. Teeth 70 of pump gear 44 can be at least seventy
teeth in number. While FIG. 6 only provides a partial view of pump
gear 44, it should be understood that the features of pump gear 44
shown in FIG. 6 are repeated throughout the entire circumference of
pump gear 44 and to all of teeth 70 of pump gear 44.
[0029] In addition to outside diameter D.sub.1, pitch diameter
D.sub.2, and root diameter D.sub.3, hub outer diameter D4, hub hole
diameter D5, axial width W1 of teeth 70, and hub axial width W2 are
additional dimensions of pump gear 44 that can be sized to maximize
the performance of pump gear 44 and pump assembly 42. As best shown
in FIG. 5, a ratio (D.sub.4/D.sub.1) of hub outer diameter D.sub.4
and outside diameter D.sub.1 of pump gear 44 can be about 0.242 and
0.251. Optimizing the ratio (D.sub.4/D.sub.1) of hub outer diameter
D.sub.4 and outside diameter D.sub.1 of pump gear 44 helps define
the most efficient length for spokes 68 and the most efficient size
for center hub 62. Properly sizing spokes 68 will help ensure that
spokes 68 are strong enough to transfer torque between rim 60 and
center hub 62. Properly sizing center hub 62 helps ensure that
center hub 62 is robust enough to withstand the operational
stresses of pump assembly 42 while ensuring that center hub 62 is
not unnecessarily oversized. Oversizing center hub 62 can
unnecessarily add weight to pump assembly 42, IDG 10, and the
aircraft that utilizes IDG 10, thus leading to decreased fuel
efficiency and increased fuel cost.
[0030] As shown in FIGS. 4 and 5, a ratio (D.sub.5/D.sub.4) of hub
hole diameter D.sub.5 and hub outer diameter D.sub.4 can be about
0.622 to about 0.647. Optimizing the ratio (D.sub.5/D.sub.4) of hub
hole diameter D.sub.5 and hub outer diameter D.sub.4 also helps
ensure that center hub 62 is robust enough to withstand the
operational stresses of pump assembly 42 while ensuring that center
hub 62 is not unnecessarily oversized.
[0031] Best shown in FIG. 5, a ratio (W.sub.1/W.sub.2) of axial
width W.sub.1 of teeth 70 and hub axial width W.sub.2 can be about
0.532 to about 0.580. By optimizing the ratio (W.sub.1/W.sub.2) of
axial width W.sub.1 of teeth 70 and hub axial width W.sub.2 the
size of pump gear 44 is large enough in the direction of center
axis CA to help teeth 70 on pump gear 44 maintain contact with
accessory drive gear 38 (shown in FIG. 2) and resist deformation
during operation of IDG 10.
[0032] In view of the foregoing description, it will be recognized
that the present disclosure provides numerous advantages and
benefits. For example, the present disclosure provides coaxially
aligned accessory drive gear 38, output ring gear 34, and input
driven gear 32 all disposed on the same side or end of hydraulic
speed trimming device 28. Coaxially aligning accessory drive gear
38, output ring gear 34, and input driven gear 32 within IDG 10 can
help reduce the overall size of IDG 10 by moving the accessory
drive gear 38, output ring gear 34, and input driven gear 32 into a
smaller space. Reducing the overall size of IDG 10 helps improve
the fuel efficiency of any aircraft that incorporates IDG 10 by
reducing the overall weight of the aircraft. Positioning accessory
drive gear 38, output ring gear 34, and input driven gear 32 on the
same side or end of hydraulic speed trimming device 28 can also
help improve maintenance accessibility of accessory drive gear 38,
output ring gear 34, and input driven gear 32. Should an operator
need to inspect or perform maintenance on accessory drive gear 38,
output ring gear 34, and input driven gear 32, the operator need
only remove a portion of housing assembly 12, such as input housing
14, to access accessory drive gear 38, generator driven gear 36,
and input driven gear 32.
[0033] The present disclosure also provides IDG 10 with pump
assembly 42 with charge pump 82, scavenge pump 84, and inversion
pump 86 all disposed within pump sleeve 48. Charge pump 82,
scavenge pump 84, and inversion pump 86 can all be installed into
IDG 10 by simply connecting pump cover 46 and mounting flange 59 of
pump sleeve 48 within housing assembly 12 of IDG 10. Thus pump
assembly 42 and IDG 10 overall use fewer fasteners and less area
than IDG designs. Furthermore, aligning charge pump 82, scavenge
pump 84, and inversion pump 86 within pump sleeve 48 and pump cover
46 provides for fewer gears and other moving parts within IDG 10.
Reducing the number of gears and other moving parts within IDG 10
increases the service life of IDG 10 by reducing the amount of
internal vibration within IDG 10, amount of hardware, and the wear
and tear associated with internal vibration. Reducing the number of
gears and other moving parts within IDG 10 also reduces the weight
of IDG 10 and increases the fuel efficiency of any aircraft that
incorporates IDG 10. The present disclosure also provides gear pump
44 with a size optimized for size and weight savings while
maintaining the structural integrity of pump gear 44.
[0034] The following are non-exclusive descriptions of possible
embodiments of the present invention.
[0035] In one embodiment, an integrated drive generator includes an
input shaft and an input drive gear connected to the input shaft.
The integrated drive generator also includes an input driven gear
meshed with the input drive gear. The integrated drive generator
also includes a hydraulic speed trimming device. The hydraulic
speed trimming device includes an input shaft connected to the
input driven gear, an output shaft, an accessory drive gear
connected to the output shaft, and an output ring gear connected to
the output shaft. The input driven gear, the accessory drive gear,
and the output ring gear are coaxial and disposed proximate a first
end of the hydraulic speed trimming device. The integrated drive
generator also includes a pump assembly with a pump drive shaft and
a pump gear connected to the pump drive shaft and meshed with the
accessory drive gear.
[0036] The integrated drive generator of the preceding paragraph
can optionally include, additionally and/or alternatively, any one
or more of the following features, configurations and/or additional
components:
[0037] the pump gear is a spur gear;
[0038] an outside diameter; and a pitch diameter, wherein a ratio
of the outside diameter and the pitch diameter is about 1.027 to
about 1.029;
[0039] a root diameter, wherein a ratio of the root diameter and
the pitch diameter is about 0.957 to about 0.962;
[0040] a center hub, the center hub comprising: a hub outer
diameter; and a hub hole extending through a center of the hub
along a center axis of the pump gear, wherein a ratio of the hub
outer diameter and the outside diameter of the pump gear is about
0.242 and 0.251;
[0041] the hub hole includes a double D cross-sectional profile
with two flat sides and two rounded sides, wherein the two flat
sides define a hub hole width and the two rounded sides define a
hub hole diameter;
[0042] a ratio of the hub hole diameter and the hub outer diameter
is about 0.622 to about 0.647;
[0043] the pump gear comprises at least seventy teeth;
[0044] a ratio of an axial width of the teeth and an axial width of
the hub is about 0.532 to about 0.580; and/or
[0045] the output ring gear is connected to the output shaft by a
differential assembly disposed between the accessory drive gear and
the input driven gear.
[0046] In another embodiment, a pump gear for rotating a drive
shaft of a pump assembly of an integrated drive generator for a gas
turbine engine includes an outside diameter and a pitch diameter. A
ratio of the outside diameter and the pitch diameter is about 1.027
to about 1.029.
[0047] The pump gear of the preceding paragraph can optionally
include, additionally and/or alternatively, any one or more of the
following features, configurations and/or additional
components:
[0048] a root diameter, wherein a ratio of the root diameter and
the pitch diameter is about 0.957 to about 0.962;
[0049] a center hub, the center hub comprising: a hub outer
diameter; and a hub hole extending through a center of the hub
along a center axis of the pump gear, wherein a ratio of the hub
outer diameter and the outside diameter of the pump gear is about
0.242 and 0.251;
[0050] the hub hole includes a double D cross-sectional profile
with two flat sides and two rounded sides, wherein the two flat
sides define a hub hole width and the two rounded sides define a
hub hole diameter, and wherein a ratio of the hub hole diameter and
the hub outer diameter is about 0.622 to about 0.647;
[0051] the pump gear comprises at least seventy teeth; and/or
[0052] a ratio of an axial width of the teeth and an axial width of
the hub is about 0.532 to about 0.580.
[0053] Any relative terms or terms of degree used herein, such as
"substantially", "essentially", "generally", "approximately", and
the like, should be interpreted in accordance with and subject to
any applicable definitions or limits expressly stated herein. In
all instances, any relative terms or terms of degree used herein
should be interpreted to broadly encompass any relevant disclosed
embodiments as well as such ranges or variations as would be
understood by a person of ordinary skill in the art in view of the
entirety of the present disclosure, such as to encompass ordinary
manufacturing tolerance variations, incidental alignment
variations, transitory vibrations and sway movements, temporary
alignment or shape variations induced by operational conditions,
and the like.
[0054] While the invention has been described with reference to an
exemplary embodiment(s), it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment(s) disclosed, but that the invention will
include all embodiments falling within the scope of the appended
claims.
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