U.S. patent application number 13/426291 was filed with the patent office on 2013-03-28 for vafn systems with improved drive coupling assemblies and brakes.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. The applicant listed for this patent is Stephen Birn, Kevin K. Chakkera, Michael McGill, Ron Vaughan. Invention is credited to Stephen Birn, Kevin K. Chakkera, Michael McGill, Ron Vaughan.
Application Number | 20130078081 13/426291 |
Document ID | / |
Family ID | 46939627 |
Filed Date | 2013-03-28 |
United States Patent
Application |
20130078081 |
Kind Code |
A1 |
Chakkera; Kevin K. ; et
al. |
March 28, 2013 |
VAFN SYSTEMS WITH IMPROVED DRIVE COUPLING ASSEMBLIES AND BRAKES
Abstract
An actuation system is provided for a variable area fan nozzle
assembly of an aircraft. The actuation system includes a motor
configured to generate a torque; a nozzle; and a drive coupling
assembly coupled to the motor and the nozzle. The drive coupling
assembly includes a first position in which the torque from the
motor is transferred to the nozzle to translate the nozzle and a
second position in which the torque from the motor is not
transferred to the nozzle. The drive coupling assembly includes a
first end portion and a second end portion, the first and second
end portions mating with one another in the first position and
disengaged from one another in the second position.
Inventors: |
Chakkera; Kevin K.;
(Chandler, AZ) ; Vaughan; Ron; (Gilbert, AZ)
; McGill; Michael; (Lake Forest, CA) ; Birn;
Stephen; (Long Beach, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chakkera; Kevin K.
Vaughan; Ron
McGill; Michael
Birn; Stephen |
Chandler
Gilbert
Lake Forest
Long Beach |
AZ
AZ
CA
CA |
US
US
US
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
Morristown
NJ
|
Family ID: |
46939627 |
Appl. No.: |
13/426291 |
Filed: |
March 21, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61540325 |
Sep 28, 2011 |
|
|
|
61540318 |
Sep 28, 2011 |
|
|
|
Current U.S.
Class: |
415/150 |
Current CPC
Class: |
F02K 1/70 20130101; F02K
1/64 20130101; F02K 1/766 20130101; F02K 1/68 20130101; F02K 1/763
20130101; Y02T 50/671 20130101; Y02T 50/60 20130101 |
Class at
Publication: |
415/150 |
International
Class: |
F01D 17/10 20060101
F01D017/10; F01D 17/00 20060101 F01D017/00 |
Claims
1. An actuation system for a variable area fan nozzle assembly of
an aircraft, the system comprising: a motor configured to generate
a torque; a nozzle; and a drive coupling assembly coupled to the
motor and the nozzle, the drive coupling assembly having a first
position in which the torque from the motor is transferred to the
nozzle to translate the nozzle and a second position in which the
torque from the motor is not transferred to the nozzle, wherein the
drive coupling assembly comprises a first end portion and a second
end portion, the first and second end portions mating with one
another in the first position and disengaged from one another in
the second position.
2. The actuation system of claim 1, wherein the drive coupling
assembly is mounted on a transcowl such that the drive coupling is
in the first position when the transcowl is stowed and in the
second position when the transcowl is deployed.
3. The actuation system of claim 2, wherein the drive coupling
assembly comprises a first drive shaft coupled to the first end
portion; a second drive shaft coupled to the second end portion;
and a nozzle actuator coupled to the second drive shaft and mounted
on the transcowl such that deployment of the transcowl moves the
nozzle actuator and the second drive shaft away from the first
drive shaft such that the first and second end portion
disengage.
4. The actuation system of claim 3, further comprising a fixed
structure gearbox coupled to the first drive shaft.
5. The actuation system of claim 3, wherein the nozzle actuator
comprises a gimbal that couples the second drive shaft to the
nozzle such that rotation of the second drive shaft translates the
nozzle.
6. The actuation system of claim 3, wherein the first end portion
includes a first end face with pins extending therefrom.
7. The actuation system of claim 6, wherein the second end portion
includes a second end face with tabs extending therefrom that
define gaps between adjacent tabs.
8. The actuation system of claim 7, wherein, in the first position,
the pins of the first end portion extend into the gaps to engage
the tabs of the second end portion to transfer torque between the
first drive shaft and the second drive shaft.
9. The actuation system of claim 8, wherein the first end portion
further includes recesses to house the pins in a retracted position
and springs to bias the pins into an extended position.
10. The actuation system of claim 9, each of the pins is configured
to retract into the retracted position upon initial engagement with
one of the tabs until rotation of the first drive shaft aligns each
of the pins with the gap to enable extension of each of the pins
into the gap.
11. The actuation system of claim 3, wherein the nozzle actuator
includes a braking assembly to prevent rotation of the second drive
shaft when the drive coupling assembly is in the second
position.
12. The actuation system of claim 11, wherein the braking assembly
includes a rotor mounted on the second drive shaft, a stator
mounted proximate to the rotor, and a spring that biases the stator
against the rotor with a spring force to prevent rotation of the
second drive shaft when the drive coupling assembly is in the
second position.
13. The actuation system of claim 12, wherein the first end portion
is configured to mate with the second end portion in the first
portion to overcome the spring force, separate the rotor and the
stator, and enable rotation of the second drive shaft.
14. The actuation system of claim 11, wherein the braking assembly
includes a first knurled surface mounted on the second drive shaft,
a second knurled surface mounted proximate to the first knurled
surface, and a spring that biases the second knurled surface
against the first knurled surface with a spring force to prevent
rotation of the second drive shaft when the drive coupling assembly
is in the second position.
15. A drive coupling assembly for driving variable area fan nozzle
with a motor of an aircraft, the assembly comprising: a first
portion coupled to the motor; and a second portion coupled to the
nozzle, the second portion having a first position engaging the
first portion in which the torque from the motor is transferred to
the nozzle to translate the nozzle and having a second position
decoupled from the first portion in which the torque from the motor
is not transferred to the nozzle.
16. The drive coupling assembly of claim 15, wherein the first
portion includes a first end face with pins extending
therefrom.
17. The drive coupling assembly of claim 16, wherein the second
portion includes a second end face with tabs extending therefrom
that define gaps between adjacent tabs.
18. The drive coupling assembly of claim 17, wherein, in the first
position, the pins of the first end portion extend into the gaps to
engage the tabs of the second end portion to transfer torque
between the first portion and the second portion.
19. The drive coupling assembly of claim 18, wherein the first end
portion further includes recesses to house the pins in a retracted
position and springs to bias the pins into an extended
position.
20. The drive coupling assembly of claim 19, each of the pins is
configured to retract into the retracted position upon initial
engagement with one of the tabs until rotation of the first portion
aligns each of the pins with the gap to enable extension of each of
the pins into the gap.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/540,325, filed Sep. 28, 2011 and U.S.
Provisional Application No. 61/540,318, filed Sep. 28, 2011, the
entirety of each being hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to variable area fan nozzle
assemblies and more particularly to actuation systems for variable
area fan nozzle assemblies of jet engines.
BACKGROUND
[0003] Conventional gas turbine engines generally include a fan
section and a core engine with one or more compressors, a
combustion section, and one or more turbines. The fan section and
the core engine are disposed about a longitudinal axis and are
enclosed within a case assembly. During operation, the fan section
induces a first portion of air into the core engine and a second
portion of air into a bypass flow path.
[0004] In the core engine, air is compressed, mixed with fuel,
combusted, expanded through the turbines, and subsequently
discharged from the core engine through an exhaust nozzle system.
The bypass air is directed through the bypass flow path, disposed
radially outward of the primary airflow path, and discharged
through an annular fan exhaust nozzle system defined between a fan
case and an inner cowl. A majority of thrust is produced by the
pressurized fan air discharged through the fan exhaust nozzle, the
remaining thrust being provided from the combustion gases
discharged through the core exhaust nozzle.
[0005] The engine may include a thrust reverser system and a fan
nozzle system to manipulate air flow through the bypass flow path.
Thrust reversers function to enhance the braking of the aircraft
during landing. When deployed, a thrust reverser redirects the
rearward thrust via the bypass flow path of the jet engine to a
forward or semi-forward direction to decelerate the aircraft upon
landing. When in the stowed position, the thrust reversers are in a
position that generally does not redirect the engine thrust.
[0006] The nozzle system may be positioned on or adjacent to the
transcowls of a thrust reverser system. Some gas turbine engines
have implemented variable area fan nozzles. The variable area fan
nozzles provide a smaller fan exit nozzle diameter to optimize
operation during certain conditions. However, existing variable
area fan nozzles typically utilize relatively complex mechanisms
that undesirably increase overall engine weight and decrease fuel
efficiency.
[0007] Accordingly, it is desirable to provide improved variable
area fan nozzles that, for example, reduce complexity, weight, and
cost in a turbofan engine. Furthermore, other desirable features
and characteristics of the present invention will become apparent
from the subsequent detailed description of the invention and the
appended claims, taken in conjunction with the accompanying
drawings and this background of the invention.
BRIEF SUMMARY
[0008] In accordance with an exemplary embodiment, an actuation
system is provided for a variable area fan nozzle assembly of an
aircraft. The actuation system includes a motor configured to
generate a torque; a nozzle; and a drive coupling assembly coupled
to the motor and the nozzle. The drive coupling assembly includes a
first position in which the torque from the motor is transferred to
the nozzle to translate the nozzle and a second position in which
the torque from the motor is not transferred to the nozzle. The
drive coupling assembly includes a first end portion and a second
end portion, the first and second end portions mating with one
another in the first position and disengaged from one another in
the second position.
[0009] In accordance with another exemplary embodiment, a drive
coupling assembly is provided for driving variable area fan nozzle
with a motor of an aircraft. The assembly includes a first portion
coupled to the motor; and a second portion coupled to the nozzle.
The second portion has a first position engaging the first portion
in which the torque from the motor is transferred to the nozzle to
translate the nozzle and a second position decoupled from the first
portion in which the torque from the motor is not transferred to
the nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will hereinafter be described in
conjunction with the following drawing figures, wherein like
numerals denote like elements, and
[0011] FIG. 1 is a perspective view of an aircraft engine system
according to an exemplary embodiment;
[0012] FIG. 2 is a schematic cross-sectional view of the engine
system of FIG. 1 according to an exemplary embodiment;
[0013] FIG. 3 is a partial, more detailed cross-sectional view of
the engine system of FIG. 2 with a transcowl and nozzle in a first
position according to an exemplary embodiment;
[0014] FIG. 4 is a partial, more detailed cross-sectional view of
the engine system of FIG. 2 with a transcowl in a second position
according to an exemplary embodiment;
[0015] FIG. 5 is a partial, more detailed cross-sectional view of
the engine system of FIG. 2 with a nozzle in a second position
according to an exemplary embodiment;
[0016] FIG. 6 is a simplified functional schematic representation
of an actuator system associated with the engine system of FIG. 2
according to an exemplary embodiment;
[0017] FIG. 7 is a cross-sectional view of a first portion of a
drive coupling assembly of the actuator system of FIG. 6 according
to an exemplary embodiment;
[0018] FIG. 8 is an end view of the first portion of the drive
coupling assembly of FIG. 7 according to an exemplary
embodiment;
[0019] FIG. 9 is a cross-sectional view of a second portion of a
drive coupling assembly of the actuator system of FIG. 6 according
to an exemplary embodiment;
[0020] FIG. 10 is an end view of the second portion of the drive
coupling assembly of FIG. 9 according to an exemplary
embodiment;
[0021] FIG. 11 is a partial, cross-sectional view of the drive
coupling assembly of FIG. 9 in an unlocked position according to an
exemplary embodiment; and
[0022] FIG. 12 is a cross-sectional view of a second portion of a
drive coupling assembly of the actuator system of FIG. 6 according
to an alternate exemplary embodiment.
DETAILED DESCRIPTION
[0023] The following detailed description is merely exemplary in
nature and is not intended to limit the invention or the
application and uses of the invention. As used herein, the word
"exemplary" means "serving as an example, instance, or
illustration." Thus, any embodiment described herein as "exemplary"
is not necessarily to be construed as preferred or advantageous
over other embodiments. All of the embodiments described herein are
exemplary embodiments provided to enable persons skilled in the art
to make or use the invention and not to limit the scope of the
invention which is defined by the claims. Furthermore, there is no
intention to be bound by any expressed or implied theory presented
in the preceding technical field, background, brief summary, or the
following detailed description.
[0024] FIG. 1 is a perspective view of portions of an aircraft jet
engine system 100 with a fan case 102. Typically, the fan case 102
encloses a turbofan engine, as described below, and mounts the
engine for aircraft operation. As also discussed below, the engine
system 100 may include a case assembly 110 to optimize
operation.
[0025] FIG. 2 is a schematic cross-sectional view of the engine
system 100 of FIG. 1. The engine system 100 is circumferentially
disposed about an engine centerline 200. The engine system 100
includes a fan 210, a low pressure compressor 220, a high pressure
compressor 222, a combustion section 230, a high pressure turbine
240, and a low pressure turbine 242 arranged around an engine shaft
250. Typically, air is compressed in the compressors 220, 222,
mixed with fuel and burned in the combustion section 230, and
expanded in the turbines 240, 242. The turbines 240, 242 include
rotors coupled for rotation with the engine shaft to drive the
compressors 220, 222 and the fan 210 in response to the expansion
of combustion gases.
[0026] In the example shown, the engine system 100 is a gas turbine
bypass turbofan arrangement in which the diameter of the fan 210 is
larger than that of the compressors 220, 222. As such, the case (or
nacelle) 102 extends circumferentially about the fan 210 to define
a bypass air flow path 212 extending between the case 102 and an
inner cowl 224, which generally surrounds the compressors 220, 222,
combustion section 230, and turbines 240, 242.
[0027] In operation, the fan 210 draws air into the engine system
100 as core flow 204 and into the bypass air flow path 212 as
bypass air flow 206. A rear exhaust 260 discharges the bypass air
flow 206 from the engine system 100, and the core flow 204 is
discharged from a passage between the inner cowl 224 and a tail
cone 262 to produce thrust.
[0028] As described in greater detail below, the case assembly 110
generally includes a thrust reverser actuation system (TRAS) 112
and a variable area fan nozzle (VAFN) system 114 to manipulate
bypass air flow 206 in the flow path 212. In general, the TRAS 112
functions to selectively block the bypass air flow path 212 of the
engine to provide braking to the aircraft, e.g., as redirected
thrust. The VAFN system 114 functions to selectively adjust the
flow area of the bypass air flow path 212 to optimize engine
operation.
[0029] FIGS. 3-5 illustrate the operation of the TRAS 112 and VAFN
system 114 relative to the bypass air flow path 212. In particular,
FIG. 3 is a partial, more detailed cross-sectional view of the
aircraft engine of FIG. 2 with the TRAS 112 and VAFN system 114 in
a first position. FIG. 4 is a partial, more detailed
cross-sectional view of the aircraft engine of FIG. 2 with the TRAS
112 in a second position, and FIG. 5 is a partial, more detailed
cross-sectional view of the aircraft engine of FIG. 2 with the VAFN
system 114 in a second position.
[0030] As is described in greater detail below, the TRAS 112
includes one or more semi-circular transcowls (or "reverser cowls")
300 that are positioned circumferentially on the outside of the jet
engine fan case 102 (FIG. 1), typically on a fixed structure or
torque box. In one exemplary embodiment, the TRAS 112 includes a
pair of semi-circular transcowls 300 that extend around the case
102. The VAFN system 114 includes trailing edge fan nozzles 400
arranged at the downstream ends of the transcowls 300. Additional
details about the operation and deployment of the transcowls 300
and nozzles 400 will be provided below with respect to FIGS. 3-5
prior to a more detailed description of the VAFN system 114.
[0031] As shown more particularly in FIG. 3, the transcowls 300
cover a plurality of vanes 302, which may be cascade-type vanes are
positioned between the transcowls 300 and a bypass air flow path
212. When in the stowed position, as depicted in FIG. 3, the
transcowls 300 are pressed against one or more stow seals, which
keep air in the bypass air flow path 212. The transcowls 300 are
mechanically linked to a series of blocker doors 304 via a drag
link 306. In the stowed position, the blocker doors 304 form a
portion of an outer wall and are therefore oriented parallel to the
bypass air flow path 212.
[0032] However, as is shown in FIG. 4, when the TRAS 112 is
commanded to deploy, the transcowls 300 are translated aft, causing
the blocker doors 304 to rotate into a deployed position, such that
the bypass air flow path 212 is blocked. This also causes the vanes
302 to be exposed and the bypass air flow to be redirected out the
vanes 302. The redirection of the bypass air flow in a forward
direction creates a reverse thrust and thus works to slow the
airplane.
[0033] Now referring FIG. 5, which depicts the TRAS 112 in the
stowed position, the VAFN system 114 may selectively adjust the
nozzles 400 mounted on the trailing edges of the transcowls 300 to
optimize the engine performance under different flight conditions.
The nozzles 400 may be nozzle-like annular airfoil structures
selectively translated (i.e., moved fore and aft) to vary the fan
nozzle's exit area and to adjust an amount of engine bypass flow.
As compared to FIG. 3, the nozzles 400 in FIG. 5 have been
translated aft. Any number of nozzles 400 may be provided, although
in one exemplary embodiment, two nozzles 400 are provided.
[0034] As such, the transcowls 300 and nozzles 400 are selectively
translated with one or more actuation systems. In one exemplary
embodiment, the nozzles 400 are only operated when the transcowl
300 is in the stowed position. In other words, the nozzles 400 are
not operated when the aircraft is landing in this exemplary
embodiment. As described in greater detail below, the actuation
system of the VAFN system 114 functions to prevent movement of the
nozzles 400 when the TRAS 112 is deployed.
[0035] FIG. 6 is a simplified functional schematic representation
of an actuation system 600 of the VAFN system 114 according to an
exemplary embodiment. The actuation system 600 modulates the
variable area fan nozzle effective flow area by moving the vane
airfoil position from 0% to 100% of stroke. As noted above, the
case assembly 110 (FIG. 1) includes a fixed torque box (not shown)
and translating thrust reverser transcowls 300. Referring briefly
to the TRAS 112 (FIGS. 3-5), the semi-circular transcowls 300 may
operate on sliders on upper and lower beams, and as described
below, at least a portion of the VAFN system 114 may be mounted on
the transcowls 300.
[0036] The actuation system 600 includes one or more power drive
units (PDUs) 610. Each PDU 610 is an integrated rotor, brake, and
optionally, a gearbox. The motors are coupled to a controller that
receives signals from a controller 612, such as a FADEC. Flexible
drive shafts 620 drive the gearboxes 630 mounted to the fixed
structure (e.g., a stationary torque box). The gearboxes 630 may
be, for example, bevel set gearboxes.
[0037] The torque from the PDUs 610 actuates the nozzles 400 via
the drive shafts 620 and gearboxes 630, and this torque may be
further transferred with drive coupling assemblies 640. One drive
coupling assembly 640 will be described, although more than one
drive coupling assembly 640 may be provided. In the exemplary
embodiment of FIG. 6, four drive coupling assemblies 640 are
depicted such that a first pair of drive coupling assemblies 640
coordinate to drive one of the nozzles 400 and a second pair of
drive coupling assemblies 640 coordinate to drive the other nozzle
400. Any suitable arrangement may be provided.
[0038] Each drive coupling assembly 640 includes first drive shaft
642, a selectively disengageable drive coupling 644, a nozzle
actuator 650, a second drive shaft 652, and gimbal 654. A more
detailed description of the drive coupling assembly 640 is provided
below after a general description of the operation.
[0039] The first drive shaft 642 extends from the fixed structure
gearbox 630 and may be selectively rotated at the first structure
gearbox 630. The first drive shaft 642 is configured to
rotationally engage the second drive shaft 652 at the drive
coupling 644, as discussed in greater below. As such, when engaged,
the second drive shaft 652 rotates with the first drive shaft
642.
[0040] The second drive shaft 652 extends through and is coupled to
the nozzle actuator 650, which is mounted on the transcowl 300. As
a result of this arrangement, the gearbox 630 and nozzle actuator
650 move relative to one another in a longitudinal direction as the
transcowl 300 is stowed and retracted. In other words, the drive
coupling 644 engages and disengages the first and second drive
shafts 642, 652 based on the position of the transcowl 300. In the
view of FIG. 6, the drive coupling 640 is disengaged, thus
preventing the first drive shaft 642 from transferring torque to
the second drive shaft 652. Although not shown in FIG. 6, the
nozzle actuator 650 further includes a brake mechanism to prevent
rotation of the second drive shaft 652 when the drive coupling 644
is disengaged.
[0041] The nozzle actuator 650 is typically a ballscrew actuator
such that the second drive shaft 652 translates forward and aft
when rotated. The second drive shaft 652 extends to the gimbal 654,
which is mounted on the nozzle 400. As the second drive shaft 652
translates, it also translates the gimbal 654 and thus the nozzle
400. As such, the nozzle 400 is actuated back and forth by the
translating drive shaft 652. Accordingly, the torque from the PDUs
610 may be transferred to linear movement of the nozzle 400 when
the drive coupling 644 is engaged. Additionally, a manual drive
unit 660 mounts to each PDU 610 and mates with gearshaft 620
allowing for manual extension and retraction of the nozzles
400.
[0042] Since the nozzle actuator 650 only actuates the nozzle 400
when the drive coupling 644 is engaged, the nozzles 400 may only
operate when the thrust reverser transcowls 300 are stowed and
locked (e.g., when the transcowls are in a position such that the
drive coupling 644 engages). At that time, the drive coupling 644
engages the gearbox on the fixed torque box to the nozzle actuator
650 and simultaneously unlocks the drive coupling assembly 640 to
enable fan nozzle operation during takeoff, cruise, and prior to
landing and reverser operation. When the aircraft lands and the
thrust reverser transcowls 300 are commanded to deploy, the drive
coupling 644 disengages and the drive coupling assembly 640 is
locked. Additional details of the coupling/decoupling mechanism are
discussed below.
[0043] Accordingly, in the exemplary embodiment shown in FIG. 6,
the actuator system includes: two PDUs (integrated motor, brake
& gearbox located at 3 and 9 o'clock); one controller; four
gearboxes mounted on fixed structure; four ball screw actuators
mounted on transcowl; two nozzle position indicators (RVDT/LVDT);
five flexible shafts; one or two Manual Drive Units; Electrical
Harnesses; and four drive couplings engaged only when transcowl is
stowed. Any suitable arrangement may be provided. For example, in
another exemplary embodiment 6, the actuator system includes: one
PDU (integrated motor, brake & gearbox located at 3, 9 or 12
o'clock); one controller; four gearboxes mounted on fixed
structure; four ballscrew actuators mounted on transcowl; two
nozzle position indicators (RVDT/LVDT); four flexible shafts; one
Manual Drive Unit; Electrical Harnesses; and four drive couplings
engaged only when transcowl is stowed. The actuators described
herein may be electrical, mechanical, pneumatic, hydraulic, or the
like, and can be interconnected by appropriate power cables and
conduits (not shown).
[0044] As described above, the actuator system 600 only enables
driving of the nozzles 400 when the transcowls 300 are stowed. In
particular, FIGS. 7-9 illustrate portions of the drive coupling
assembly 640 that enable this function.
[0045] FIG. 7 is a cross-sectional view of an end portion 700 of
the first drive shaft 642 of the drive coupling assembly 640 that
extends from the fixed structure gearbox 630 (FIG. 6). FIG. 8 is an
end or side view of the end portion 700 of the first drive shaft
642. The end portion 700 of the first drive shaft 642 has a
generally cylindrical end with one or more pins 704. The pins 704
are spring loaded in recesses 706 within the end portion 700 such
that the pins 704 are biased outward by the springs 708 and may
retract into the recesses 706. As noted above, during operation,
the first drive shaft 642 and end portion 700 are rotated.
[0046] FIG. 9 is a cross-sectional view of the second drive shaft
652 and nozzle actuator 650 of the drive coupling assembly 640.
Although not shown, the nozzle actuator 650 is rotationally
symmetric about centerline 902. As noted above, the second drive
shaft 652 extends through the nozzle actuator 650 to the nozzle 400
(FIG. 6). FIG. 10 is an end or side view of the end portion 750 of
the second drive shaft 652. The end portion 750 includes one or
more tabs 754 that create gaps 756.
[0047] Referring initially to FIGS. 8 and 10, the end portions 700,
750 form the disengageable drive coupling 644. When engaged, the
end portions 700, 750 transfer torque the drive the nozzles 400
(FIG. 6), and when disengaged, the end portions 700, 750 do not
transfer torque to drive the nozzles 400.
[0048] In particular, when the end portion 700 of the first drive
shaft 642 presses against the end portion 750 of the second drive
shaft 652, one or more of the pins 704 are positioned within the
gaps 756. In this condition, the portions 700, 750 are engaged or
coupled such that the first portion 700 can rotationally drive the
second portion 750. As described above, the end portions 700, 750
are typically engaged when the transcowls 300 (FIG. 6) are in a
stowed position, and when the transcowl 300 is extended, the second
drive shaft 652 is moved away from the first drive shaft 642 such
that the end portions 700, 750 do not engage one another to
transfer torque.
[0049] When the end portions 700, 750 are initially pressed
together, e.g., when the transcowls 300 are transitioning from a
deployed position to a stowed position, the one or more of the pins
704 of the first drive shaft 642 may encounter tabs 754 of the
second drive shaft 652. Any such pin 704 may initially retract into
the respective recess 706 until rotation of the first drive shaft
642 aligns the pin 704 with a gap 756 at which time the respective
spring 708 biases the pin 704 out of the recess 706 and into the
gap 756 to thus drivingly engage the end portions 700, 750.
[0050] As particularly shown in FIG. 11, when the first drive shaft
642 is disengaged from the second drive shaft 652, it is
advantageous if the nozzle actuator 650 is maintained in a fixed
position. As such, the nozzle actuator 650 includes a brake
assembly 780. Particularly, the second drive shaft 652 is splined
with a number of rotors 784, which are interposed between a number
of stators 786. The stators 786 are biased forward by a spring
758.
[0051] When the end portions 700, 750 are decoupled from one
another, the spring 788 biases the stators 786 forward to
frictionally engage the rotors 784, thus preventing the rotors 784
from rotating, as well as the second drive shaft 652 from movement.
In effect, the brake assembly 780 is a disc brake during a
disengaged scenario.
[0052] When the end portions 700, 750 are coupled to one another,
the first end portion 700 pushes the second end portion 750 in an
aft direction, which pushes the second drive shaft 652 against the
spring 788 to disengage the stators 786 from the rotors 784 to
create gaps 790 to thus enable relative movement between the
stators 786 and the rotors 784, which in turn enables rotation of
the second drive shaft 652. This arrangement is partially shown in
FIG. 11, which is the schematic cross-sectional view of the nozzle
actuator 650 when the end portions 700, 750 are engaged with one
another. As shown, the coupling between the end portions 700 and
750 releases the brake assembly 780 to enable movement of the
nozzle actuator 650, and thus, the nozzles 400.
[0053] FIG. 12 is a more detailed view of portions of the actuator
system in according to a second exemplary embodiment. In contrast
to the brake assembly 780 of FIG. 10, the brake assembly 880 of
FIG. 12 includes a first knurled end portion (or "poker chip") 802
that is spring biased with a spring 810 against a second knurled
end portion (or "poker chip") 804 mounted on a stationary
component. As such, when the end portions 802, 804 are disengaged,
the spring 810 pushes the knurled end portions 802, 804 together to
restrict movement. However, when the knurled end portions 802, 804
are engaged with one another, the aft movement of the first end
portion 802 acts against the spring force to separate the knurled
end portions 802, 804, thereby allowing rotation of the drive shaft
and nozzle actuator. Other brake arrangements may be provided.
[0054] Accordingly, exemplary embodiments provide an
engaging/disengaging drive coupling with synchronized actuator
locking and unlocking feature. The coupling is disengaged during
reverser translation. The coupling includes a plurality of pins on
one half of the coupling that overlap tabs on the other half of the
coupling to drive the actuator. The pins may be spring loaded such
that the coupling engages even when a pin and tab initially align
with one another. The number of pins and tabs will be such as to
ensure engagement of at least one pin with at least one tab to
drive the nozzle actuator. When the coupling halves contact, the
actuator gearbox coupling half translates to unlock the locking
mechanism by overcoming the spring. This allows the nozzle actuator
to be driven by the torque box gear drive through the coupling. The
lock mechanism may be any mechanical spring loaded locking
mechanism. Examples include a disc brake locking device or a poker
chip locking device. The lock mechanism has a splined sliding shaft
attached to the coupling half at one end and to the stator of the
disc brake (or half of the poker chip) at the other end. When the
reverse cowl is stowed, the coupling half slides to unlock the
locking mechanism. The overlap between the pins and the opposing
tabs is sized to accommodate any nacelle and cowl tolerances and
keeps the actuator in position even though the lock has disengaged.
The fan nozzle is driven by actuators mounted on the translating
reverser cowl structure. Accordingly, a simple, light weight, more
reliable variable fan nozzle actuation system eliminates a gear box
on the nozzle actuators and provides an engaging/disengaging drive
coupling with synchronized actuator locking and unlocking
features.
[0055] While at least one exemplary embodiment has been presented
in the foregoing detailed description of the invention, it should
be appreciated that a vast number of variations exist. It should
also be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention. It being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope of the invention as set forth in the appended
claims.
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