Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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WIND DRIVEN POWER GENERATION SYSTEM
BACKGROUND
[0001] Embodiments of the invention relate to devices for generating
electrical power using
wind as a motive force.
[0002] The wind turbine industry has been experiencing unprecedented growth in
recent
years due to the demand for clean, renewable energy. Small and efficient
design has been a
central objective of the wind turbine industry, to reduce the cost of the wind
turbine and in some
cases increase the turbine's efficiency. However, small and efficiently
designed wind turbines
may be difficult to achieve for a multitude of reasons.
[0003] Wind turbines typically include a transmission, such as a gearbox, to
transfer and
adjust power from turbine blades to a generator. Specifically, the
transmission adjusts the speed
and the torque from the rotor blades, allowing energy to be efficiently
generated in the generator
of the wind turbine. However, not only does the transmission transfer the wind
generated input
to an electric machine for power generation, but it also reacts the wind-
generated input torque by
an equal and opposite reaction torque. This reaction torque is generally
proportional to the size
and power output of the turbine. Thus, as the size and power output is
increased, the reaction
torque is also increased. As such, as the power generated by wind turbines
continues to rise, so
does the reaction torque that is provided by the transmission, thus
frustrating the goal of
maintaining a small and efficient wind turbine design.
[0004] In the past, attempts have been made to increase the size of various
coupling
hardware, such as bolts, in the transmission housing to compensate for the
increased reaction
torque carried by the transmission. Likewise, the overall size of the
transmission housing may
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also be increased to compensate for the increased reaction torque. However, in
some
transmission designs, such as differential planetary gearboxes, the size of
the coupling hardware
may be restricted due to location, size, etc., of other components included in
the transmission.
Further, requirements related to locating, packaging, and servicing the
transmission in the wind
turbine, and properly installing and mounting the transmission to the wind
driven blades and the
electric power generation units, may also limit the ability to increase the
coupling elements of the
transmission housing and/or the size of the transmission housing.
[0005] Additionally, standardization of various components included in wind
turbines has
been slow to catch on, due to the rapid growth. Many smaller manufacturers
order small
production runs of components, such as transmissions, designed to meet
individual
specifications, necessitating a unique manufacturing process. Some
transmission manufacturers
have made attempts to include an integrated bearing, receiving the majority of
the loads from the
rotor blades and the rotor head, into the transmission, decreasing the
transmissions modularity.
The integrated bearing may be positioned at various locations within the
transmission,
preventing easy installation. Consequently, removal and repair of the bearing
may be difficult
and laborious. The decreased modularity, as well as the difficult installation
and removal
process, may considerably increase the cost of the transmission.
[0006] Lubrication systems are used in many wind turbines to circulate oil
through the
gearbox. The lubrication system may decrease the friction between moving
components as well
as providing cooling for components within the gearbox, thereby decreasing the
losses within the
gearbox and increasing the lifespan of the wind turbine.
[0007] Many previous lubrication systems have made attempts to externally
route oil
lines through the outer housing of the gearbox to provide lubrication fluid to
various rotating
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components in the gearbox, such as bearing and gear meshes in an upwind
portion of the
gearbox. However, due to the large size of the components included in the
gearbox and the
small diameters of the oil lines, the oil lines may become damaged, and in
some cases, ruptured
during installation and/or repair of up-tower components. Therefore, the cost
of installation and
repair may be increased. Additionally, degradation or possible failure of the
gearbox may occur
when ruptured oil lines are not discovered. Furthermore, externally directing
oil lines into
various internal components within the gearbox may be difficult, due to the
gearbox's compact
design. Therefore, proper lubrication of the gearbox may not be achieved when
using external
oil lines, thereby decreasing the lifespan of the gearbox.
BRIEF DESCRIPTION OF THE INVENTION
[0008] An embodiment of the present invention relates to a wind driven power
generation
system, e.g., for inclusion in a wind turbine having one or more wind driven
rotor blades. The
system comprises a transmission assembly, which includes a transmission and a
removable input
bearing cartridge. The transmission comprises an input carrier and a gear-
train rotatably
coupling the input carrier to a transmission output. The input carrier is
configured to transfer a
rotational input from the rotor blades to the gear-train. The removable input
bearing cartridge is
coupled to a periphery of the input carrier, exterior to the gear-train, and
is in axial alignment
with the input carrier. In this way, the removable input bearing cartridge may
be installed
subsequent to assembly of the transmission, thereby increasing the modularity
of the
transmission and allowing the transmission to be used in a multitude of wind
turbine designs.
Also, the installation and removal process is simplified, decreasing the cost
of installation as well
as repair.
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[0009] In another embodiment, the wind driven power generation system
comprises a
transmission having a gear-train and an outer housing enclosing the gear-
train. The outer
housing includes a torque reacting joint coupling a first section of the
transmission to a second
section of the outer housing. The torque reacting joint includes mating
indents between the first
and second sections. In this way, by carrying the reaction torque
substantially via the mating
indents, it is possible that coupling hardware size, as well as transmission
housing size, can be
reduced. Further, by carrying the reaction torque substantially via the mating
indents, the mating
surfaces of the first and second sections of the outer housing are more free
to flex and/or deform,
thus more evenly distributing the reaction load and improving radial alignment
of the gear-train
in the gearbox.
[0010] In another embodiment, the wind driven power generation system
comprises a
gearbox having a gear-train (including an input and an output) and a rotating
conduit internally
traversing the gear-train. The rotating conduit is configured to receive
lubrication fluid from one
or more components downstream of the rotating conduit, and to deliver
lubrication fluid to one
or more components upstream of the rotating conduit. Additionally, the
components upstream of
the rotating conduit may rotate at a different speed than components
downstream of the rotating
conduit. In this way, increased lubrication may be provided to the gearbox
while simplifying
installation and repair procedures, thereby increasing the longevity of the
wind turbine and
driving down the cost of the wind turbine.
[0011] This brief description is provided to introduce a selection of concepts
in a simplified
form that are further described below. This brief description is not intended
to identify key
features or essential features of the claimed subject matter, nor is it
intended to be used to limit
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the scope of the claimed subject matter. Furthermore, the claimed subject
matter is not limited to
implementations that solve any or all disadvantages noted in any part of this
disclosure.
BRIEF DESCRIPTION OF FIGURES
[0012] The present invention will be better understood from reading the
following
description of non-limiting embodiments, with reference to the attached
drawings, wherein
below:
[0013] FIG. 1 shows an illustration of a wind driven power generation system,
e.g., wind
turbine;
[0014] FIG. 2 illustrates a schematic depiction of a nacelle included in the
system shown in
FIG. 1;
[0015] FIG. 3 shows a cut away view of a transmission included in a wind
turbine,
according to an embodiment of the present invention;
[0016] FIGS. 4A and 4B show a detailed view of a torque reacting joint,
according to an
embodiment of the present invention;
[0017] FIG. 5A and 5B shows an exploded view of the torque reacting joint
illustrated in
FIG. 4A and 4B, including a housing mating surface and a gear-train mating
surface;
[0018] FIGS. 6A and 6B show a detailed view of a gear-train mating surface
included in the
torque reacting joint, shown in FIG. 5B;
[0019] FIGS. 7A and 7B shows a detailed view of the housing mating surface,
shown in
FIG. 5A;
[0020] FIGS. 8-9 show various detailed views of the torque reacting joint
illustrated in
FIGS. 4A and 4B;
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[0021] FIGS. 10 and 11 illustrate various isometric view of the transmission,
shown in FIG.
3;
[0022] FIG. 12 illustrates a schematic depiction of a nacelle, according to an
embodiment of
the present invention, which may be included in a power-generating wind
turbine as shown in
FIG. 1;
[0023] FIG. 13A shows a cut-away view of a gearbox and associated lubrication
system
included in a wind turbine, according to an embodiment of the present
invention;
[0024] FIG. 13B illustrates an expanded view of a rear lubrication manifold
included in the
gearbox shown in FIG. 13A;
[0025] FIGS. 13C and 13D shows various views of a tube-in-tube assembly
included in the
gearbox shown in FIG. 13A;
[0026] FIG. 13E illustrates an expanded upwind lubrication manifold included
in the
gearbox shown in FIG. 13A;
[0027] FIG. 14 illustrates a cut away side view of a transmission assembly,
according to an
embodiment of the present invention;
[0028] FIG. 15 shows an isometric view of the transmission assembly shown in
FIG. 14;
[0029] FIG. 16 illustrates a detailed view of an input bearing cartridge and
an input carrier
included in the transmission assembly, shown in FIG. 14;
[0030] FIG. 17 illustrates an isometric view of the input bearing cartridge
and the input
carrier shown in FIG. 16;
[0031] FIG. 18 shows an exploded view of the bearing cartridge and the input
carrier shown
in FIG. 16; and
[0032] FIG. 19 shows a method which may be used to assemble a transmission
assembly.
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DETAILED DESCRIPTION
[0033] Various embodiments of the present invention relate to a wind driven
power
generation system, e.g., for inclusion in a wind turbine having one or more
wind driven rotor or
turbine blades. In one embodiment, the wind driven power generation system
comprises a
transmission having a torque reacting joint configured to react torque
generated by the wind
interacting with the turbine blades. The torque reacting joint may be
configured to react a
substantial amount of the wind-generated torque while maintaining a compact
and efficient
design using mating indents in a housing of the transmission. In another
embodiment, the wind
driven power generation system comprises a gearbox having a gear-train
(including an input and
an output) and a rotating conduit internally traversing the gear-train. The
conduit is part of a
lubrication system for the wind driven power generation system. The
lubrication system may
internally direct oil to various components included in a gearbox of the wind
turbine, thereby
increasing the lubrication provided to the components, and decreasing the
likelihood of rupturing
an external lubrication line during installation and repair. In another
embodiment, the wind
driven power generation system comprises a transmission assembly with a
removable input
bearing cartridge, for increasing the modularity of the transmission and
simplifying the
installation and removal of the transmission.
[0034] FIGS. 1 and 2 describe an example wind turbine operating environment in
which the
various embodiments of the wind driven power generation system may be
used/implemented,
although they may be used in other applications or in wind turbines other than
those shown in
FIGS. 1 and 2.
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[0035] A power generating wind turbine 10 is shown in FIG. 1. The turbine
includes a
tower 12 extending substantially vertically out of a base 14. The tower may be
constructed from
a plurality of stacked components. However, it can be appreciated that
alternate configurations
of the tower are possible, such as a lattice tower. A nacelle 16 and nacelle
bedplate 18 are
positioned atop the tower. A drive unit (not shown) may be included in the
nacelle bedplate,
allowing the nacelle to rotate about a horizontal plane. The nacelle may be
positioned, by the
drive unit, directly into the wind, increasing the power output of the wind
turbine. Further in
some examples, a pitch unit controls the vertical pitch of the blades. The
nacelle houses a power
generation system having a transmission and a generator, shown in FIG. 2
discussed in greater
detail herein. Further, various power electronics and control electronics may
be housed in
nacelle 16.
[0036] As used herein, the wind turbine is positioned with the rotor pointed
into the wind,
and thus upwind refers to a longitudinal direction pointing from the generator
toward the rotor
blades and downwind refers to the opposite direction. Furthermore, upwind and
downwind
components may be used to define the relative position of components included
in the wind
turbine.
[0037] Continuing with FIG. 1, a main shaft 20 extends out of the nacelle. The
main shaft
may be coupled to a transmission by an input carrier (not shown) sharing a
common central axis
22 with the main shaft. Furthermore, the main shaft 20 may be coupled to a
rotor head 24. A
plurality of rotor blades 26 may be radially position around the rotor head
24. A wind force (not
shown, but generally corresponding to the arrow of element number "10" in FIG.
1) may act on
the rotor blades, rotating the blades and therefore the rotor head about the
central axis. Thus, the
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rotor head may be wind driven. The rotor head may also be configured to reduce
drag on the
wind turbine, thereby reducing the axial load (e.g., thrust load) on bearings
in the wind turbine.
[0038] FIG. 2 shows a detailed illustration of the nacelle 16 housing a
transmission 212
included in a power generation system 210 of the wind turbine 10. The power
generation system
210 is configured to efficiently convert rotational energy from wind driven
rotor blades to
electrical energy. The power generation system may include the transmission
212 configured to
increase the rotational speed of the main shaft 20 and a generator 214
configured to convert
mechanical energy from the transmission into electrical energy. A pitch
control system 218 may
also be included in the nacelle. The transmission 212 may include an input and
an output. The
input is configured to transfer rotation from the main shaft to a gear-train
(not shown in this
figure) and the output is configured to transfer rotation from the
transmission to the generator
214, e.g., via an output shaft 216. The transmission is configured to adjust
the speed and/or
torque of the rotational input from the wind actuated rotor head, allowing the
generator to more
efficiently utilize the rotational energy from the transmission to extract
electrical power from the
power generation system. For instance, the transmission may increase the
rotational speed of the
input, while reducing torque.
[0039] A number of suitable transmissions having an input and an output, which
may be
axially aligned, can be utilized. Specifically, in this example, a
differential planetary
transmission is used. Various types of generators may be coupled to the
transmission to produce
power in the wind turbine, such as an induction type, wound type, synchronous
type, secondary
resistance control wound induction type (rotor current control or RCC type),
secondary
excitation control wound induction type (static Scherbius or D.F. type),
permanent magnet type,
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induction multiple type, etc. Additionally, the generator may be coupled to an
electrical
transmission system, which may be routed through the tower to the base of the
wind turbine.
[0040] It can be appreciated that additional up-tower components may be
included in the
nacelle 16, such as electrical transmission components including but not
limited to a transformer,
a generator cooling system such as an open or closed loop heat exchanger, a
transmission
lubrication system, etc.
[0041] FIG. 3 shows a cut-away side view of a transmission 300, which is
included in a
wind driver power generation system according to an embodiment of the present
invention. The
transmission 300 includes a torque reacting joint 324. FIGS. 3-10 show various
embodiments of
the torque reacting joint.
[0042] In some examples, transmission 300 may be similar to transmission 212.
However,
in other examples, the transmission 300 may be another suitable transmission.
The transmission
300 may be configured to increase the speed of the rotational input from the
rotor blades,
reducing the torque. The transmission 300 may include an outer housing 302 and
a gear-train
304. In some examples, the outer housing may at least partially enclose a gear-
train and/or a
portion of the transmission. Additionally, the gear-train may include an input
carrier 306 and an
output shaft 308, forming a transmission input and output, respectively. The
input carrier may
receive rotational input from the rotor blades and the output shaft may
transfer rotational output
to a generator. It can be appreciated that in other examples, alternate inputs
and outputs may be
utilized.
[0043] As noted above, the transmission may be a differential planetary
transmission
including two power paths. The first power path includes an attachment between
the input
carrier 306 and a plurality of upwind planet gears 310. The input carrier
maybe directly coupled
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to a pinion of each respective planet gear. Each planet gear may include one
or more bearings
312 or bearing sets, allowing the planet gears to rotate. A first ring gear
314 may be in
engagement with the upwind planet gears, facilitating proper rotation of the
planet gears. The
second power path may include an attachment between the input carrier and a
second ring gear
316. In turn, the ring gear may drive one or more downwind planet gears 318.
Both the upwind
and the downwind planet gears may drive a sun gear 320 forming an output of
the transmission.
Thus, the gear-train includes two power paths which drive a sun gear forming
or coupled to an
output, such as an output shaft. In some examples, the output may include a
parallel stage shaft
rotatably coupled to the output shaft. In other examples, alternate suitable
transmissions may be
used. Additional gears may also be included in the gear-train 304.
[0044] Furthermore, additional components may also be included in the
transmission, such
as a pitch tube 322. The pitch tube may transverse the transmission as well as
house various
conduits used to control the position of components in the wind turbine, such
as the angle of the
rotor blades. Additionally, a lubrication system (not shown) may be used to
lubricate various
components included in the transmission. Further still, a cooling system (not
shown), such as an
open or closed loop cooling system, may be included in the transmission.
[0045] Continuing with FIG. 3, the transmission 300 may receive rotational
input from rotor
blades and transfer the rotational input through the gear-train, as discussed
above. A torque
reacting joint 324, included in the transmission, may be configured to react
the torque in the
gear-train through generation of an equal and opposite reaction torque. The
torque reacting joint
may be compactly and efficiently designed, increasing the torque density, and
enhancing the
space saving features of the wind turbine.
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[0046] In this example, the torque from the downwind planet gears 318 may be
transferred
to the torque reacting joint 324 through a carrier attachment 325. The torque
reacting joint 324
may be included in the outer housing 302 of the transmission, which may be
fixedly coupled to a
stationary component included in the nacelle, such as the bedplate 18,
illustrated in FIG. 1,
thereby reacting the torque in the gear-train. A suitable component, such as a
housing flange
326, may couple the outer housing of the transmission to the bedplate. Various
detailed views of
the housing flange are further illustrated in FIGS. 4A, 4B, 5A, 513, 10, and
11, discussed in
greater detail herein. It can be appreciated that the torque reacting joint
may be coupled to
alternate or additional components in the transmission or wind turbine, such
as the first ring gear
314, the transmission output including a parallel stage shaft (not shown),
and/or a generator (not
shown).
[0047] Due to installation requirements, an outer radius 328 of the torque
reacting joint, as
illustrated in FIG. 3, may be restricted. In particular, the outer radius of
the torque reacting joint
may not exceed the inner radius 330 of the housing flange 326, preventing
interference of the
inner torque reacting joint with the housing flange, allowing various tools,
such as a drill or
reamer head, to be inserted into the housing flange 326 during assembly,
disassembly, and/or
repair. Therefore, the installation process may be simplified when a compact
and efficiently
designed torque reacting joint is utilized, decreasing the cost of the wind
turbine. Various
detailed views of an example torque reacting joint are shown in FIGS. 4A-5B.
[0048] Specifically, FIG. 4A illustrates a more detailed view of the torque
reacting joint 324
included in an outer housing 302. The torque reacting joint 324 may facilitate
torque transfer
from a carrier attachment 404 to a gear-train housing 406. In this example,
carrier attachment
404 may be similar to carrier attachment 325. Further, in this example, the
carrier attachment is
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coupled to one or more planet carriers, the planet carrier fixing rotation of
the one or more planet
gears, discussed in greater detail herein with regard to FIGS. 5A and 5B. In
this example, the
torque reacting joint is radially aligned in that the gear-train and the
torque reacting joint have a
common center axis 407, allowing for proper load distribution through the
torque reacting joint
with the gear-train housing positioned upwind of the carrier attachment.
However, in other
examples, the gear-train housing may be positioned downwind of the carrier
attachment.
Further, in this example, the gear-train housing encloses a substantial
majority of the gear-train,
reducing the likelihood of unwanted particulates entering the gear-train, as
well as reducing
leakage of lubrication fluid from the gear-train.
[0049] Continuing with FIG. 4A, the torque reacting joint may include mating
indents 408
between the first and the second sections of the transmission (the carrier
attachment and the gear-
train housing, in this example), which may be circumferentially formed
(meaning that the mating
indents extend around the circumference of the torque reacting joint). The
mating indents may
include a contacted surface area. Various configurations of the mating indents
408 may be used,
such as interference keys, splines, etc. Thus, in some examples, the indents
in the torque
reacting joint may be in the shape of splines. Further, in some examples, the
indents may form
an interference fit. As should be appreciated, the term "mating indent" refers
to a structure that
defines a recess in a first part (e.g., the first section of the
transmission), which accommodates a
correspondingly shaped protuberance in a second part (e.g., the second section
of the
transmission).
[0050] In this example, the mating indents 408 may include alternating
projected and
recessed portions, 410 and 412 respectively, allowing an increased amount of
torque to be
transferred between the first and the second sections of the transmission via
the torque reacting
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joint, while maintaining a compact and efficient design, thereby increasing
the torque density. In
other examples, the mating indents may have alternate geometries. An exploded
side view of the
torque reacting joint is shown in FIG. 4B, illustrating the two section of the
transmission coupled
through the torque reacting joint.
[0051] Another exploded view of the torque reacting joint 324 is shown in FIG.
5A and 5B,
illustrating a more detailed view of the gear-train housing 406 and the
carrier attachment 404,
which may be coupled to form the torque reacting joint. Specifically FIGS. 5A
and 5B illustrate
a gear-train mating surface 502 and a housing mating surface 504. The
aforementioned surfaces
may be mated to form the mating indents of the torque reacting joint. The
housing mating
surface may further include alternating projected and recessed portions, 506
and 508
respectively, as shown in FIG. 5A. Additionally, the gear-train mating surface
may further
include alternating projected and recessed portions, 510 and 512 respectively,
as shown in FIG.
5B.
[0052] FIG. 5A illustrates the housing mating surface 504, which may also
include a
plurality of cavities 514 extending into the gear-train housing 406. In this
example, each
projected and recessed portion may include a cavity positioned proximate to
the geometric center
of each respective projected portion and recessed portion. However, in other
examples, the
number and/or position of the cavities may be adjusted depending on various
factors, such as
design requirements. Further in this example, the cavities 514 extend axially,
through the gear-
train housing 406, parallel to the common central axis 407 (e.g., central axis
of rotation) of the
transmission, and may be sized to accept fasteners, such as coupling hardware
(e.g., bolts,
screws, rivets, or the like), discussed in more detail herein.
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[0053] As illustrated in FIG. 5B, the gear-train mating surface 502 may also
include a
plurality of cavities 518, extending through the carrier attachment 404. In
this example, each
projected and recessed portion, 510 and 512 respectively, may include a cavity
positioned
proximate to the geometric center of each respective projected and recessed
portion. However,
in other examples the number and/or position of the cavities may be adjusted.
The cavities
extend axially, through the carrier attachment 404, parallel to the common
central axis 407 of the
transmission, and may be sized to accept fasteners, such as coupling hardware.
[0054] To facilitate torque transfer from the gear-train to the torque
reacting joint 324, the
carrier attachment 404 may be coupled to various components in the gear-train,
as previously
discussed. Therefore, in this example, as illustrated in FIG. 513, the carrier
attachment 404 may
include a plurality of planet attachments 526, arranged around the central
axis of rotation of the
gear-train. The planet attachments 526 may be configured to fix the rotation
of one or more
planet gears included in the gear-train, shown in FIG. 3. One or more bearings
or bearing sets
may be coupled to the planet attachments, providing axial and/or radial
support to the planet
gears included in the gear-train as well as fixing the rotation of the planet
gears. Suitable bearing
types that may be used include cylindrical roller bearings, tapered roller
bearings, or a
combination thereof. In this example, the planet attachments are cylindrical.
However, it can be
appreciated that in other examples, the geometry and/or size of the planet
attachments may be
adjusted depending on various design specifications. Further, in other
examples, the planet
attachments may be configured to fix additional or alternate components
included in the gear-
train, such as a ring gear.
[0055] Returning to FIG. 513, the carrier attachment 404 may include a central
cavity 528.
When the carrier attachment is assembled in the transmission the
transmission's output (e.g., sun
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gear) may extend through the central cavity. The transmission output may
include a central
rotating shaft and/or a sun gear.
[0056] To facilitate torque transfer from the torque reacting joint 324 to the
nacelle (e.g.,
bedplate) the transmission (e.g., the outer housing 302) may additionally
include, in some
examples, a housing flange 326, as previously discussed. The housing flange
326 includes a
plurality of axially aligned flange cavities 530 extending through the entire
housing flange.
Suitable coupling hardware, such as bolts, screws, rivets, and the like, may
be used to couple the
flange to the stationary component, such as the bedplate. In this way,
reaction torque from the
outer housing may be transferred to the nacelle. Thus, the gear-train housing
and the carrier
attachment may be fixed components. In other examples, the housing flange 326
may be
coupled to alternate suitable fixed components in the nacelle. Further still,
in other examples,
another suitable attachment mechanism, such as two or more torque arms, may be
used to fixedly
couple the outer housing 302 to a stationary component in the nacelle.
[0057] Detailed views of both of the mating surfaces, discussed above, are
shown in FIG.
6A-7B, further illustrating the geometries of each mating surfaces (the
housing mating surface
and the gear-train mating surface in this example). Specifically, FIGS. 6A and
6B show a
detailed view of the gear-train mating surface 502, shown in FIG. 513, and
FIGS. 7A-7B show a
detailed view of the housing mating surface 504, shown in FIG. 5A. Therefore,
similar parts are
labeled accordingly.
[0058] As illustrated in FIGS. 6A-6B, the projected and recessed portions, 510
and 512
respectively, may be planar and axially offset. However, in other examples,
the projected and/or
recessed portions may be curved in a convex or concave manner. In this
example, the gear-train
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mating surface is milled. However, in other examples, the gear-train mating
surface may be cast,
welded, etc.
[0059] Continuing with FIGS. 6A and 6B, the gear-train mating surface may
further include,
in some examples, a plurality of banks 602. Each bank may have three segments:
two
substantially straight segments, 604 and 606, and a curved segment 608. In
some examples, the
banks may be angled (e.g., tapered), discussed in more detail herein with
regard to FIG. 8. The
straight segments, 604 and 606, may be radially aligned with the central axis
of rotation of the
gear-train. Alternatively, in other examples, the straight segments may be
parallel. Furthermore,
the curved segment may be curved in suitable fashion, such as a parabolic
curve, U-shaped
curve, non-symmetric curve, etc. The radially alignment of the banks as well
as the curved
segment allows the mating indents to properly mate during operation of the
wind turbine.
[0060] FIGS. 7A and 7B show a detailed view of the housing mating surface 504
included
in the outer housing 302. To facilitate mating, the housing mating surface 504
may have a
similar geometry to the gear-train mating surface 502. In this example, the
projected and
recessed portions (506 and 508 respectively), included in the housing mating
surface, may be
planar and axially offset. However, in other examples, the projected and/or
recessed portions
may be curved in a convex or concave manner. Further, in this example, the
housing mating
surface is milled. However, in other examples, the housing mating surface may
be cast, welded,
etc.
[0061] Continuing with FIGS. 7A and 7B, each of the projected portions 506,
included in
the housing mating surface 504, may include four banks (702, 704, 706, and
708). In this
example, three of the banks (702, 704, and 706) are formed with an angle. The
bank 708 may be
axially aligned with the common central axis 407, illustrated in FIGS. 4A-5B.
Returning to
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FIGS. 7A and 7B, in this example, the banks 702 and 706 are radially aligned.
However, in
other examples, the banks 702 and 706 may be parallel.
[0062] FIG. 8 illustrates a detailed view of the carrier attachment mated with
the gear-train
housing, forming the torque reacting joint having mating indents. The mating
indents may be
formed with an angle 802. In this example, the angle is oblique. However, it
can be appreciated
that in other examples, the angle may be radially aligned (e.g.,
perpendicular) with the central
axis of rotation of the gear-train. The angle 802 may be defined as the angle
of intersection
between an axially aligned plane 804 and a plane 806 parallel to one of the
banks (602, 706, 708,
and 710). The angle 802 may be adjusted to allow other components to carry a
portion of the
torque as axial force, discussed in more detail herein. Various parameters may
be taken into
account when determining the angle such as the surface area of at least a
portion of the mating
surfaces, the component's size (e.g., diameter), and the material grade of the
components and the
mating surfaces. In some examples, the angle 802 may be between 6 and 30 ,
that is, 6 <
(angle 802) < 30 .
[0063] The cavities included in both the housing mating surface and the gear-
train mating
surface, 504 and 502 respectively, discussed above, may be correspondingly
positioned to allow
fasteners 910 to be inserted axially through each cavity, when the torque
reacting joint is formed
through mating of the mating surfaces. Exemplary illustrations of the torque
reacting joint
including the fasteners are shown in FIGS. 9 and 11. Suitable fasteners that
may be used include
bolts, screws, and rivets. In some examples, the fasteners may be 3/4 inch
(M20) bolts. However,
it can be appreciated that in other examples the size of the fasteners may be
adjusted or the
fasteners may not be included in the torque reacting joint.
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[0064] Due to manufacturing tolerances, such as machining tolerances, a
portion of the
mating surfaces (e.g., housing mating surface and the gear-train mating
surface) may not be in
contact. Therefore, in some examples, the fasteners may be flexible, allowing
the contacted
surface area to be increased. Specifically, in this example, the fasteners may
be configured to
flex to a greater degree than the mating indents. The size, geometry, and/or
material composition
of the torque reacting joint as well as the fasteners may be adjusted to
create the desired
flexibility in the mating indents and the fasteners. Thus, during operation of
the gear-train, the
fasteners may deform, allowing the mated surface of the torque reacting joint
to evenly distribute
the loads transferred through the torque reacting joint 324 via increased
contacted surface area.
In this way, the stress on various portions of the mating indents may be
decreased, thereby
increasing the lifespan of the torque reacting joint. In some examples, the
fasteners may be used
for tension loading only. However, in other examples, the fasteners may
provide support for
both the tension and the shear loading.
[0065] FIGS. 10 and 11 show various isometric views of the assembled
transmission and
generator. Similar parts are labeled accordingly.
[0066] In one example, the wind driven power generation system, discussed
above, may
include the mating indents 408 having a first mating surface (e.g., the
housing mating surface
504) and a second mating surface (e.g., the gear-train mating surface 502)
having a contacted
surface area. Further, in this example, the first and second mating surfaces
may have axially
offset and radially aligned projected and recessed planar surfaces (e.g., 510,
512, 506, and 508),
obliquely angled banks (e.g., 608, 702, 704, 706) joining the projected and
recessed planar
surfaces, and centrally positioned cavities (e.g., 514 and 518). The centrally
positioned cavities
may extend through each of the first and second mating surfaces. Additionally,
the cavities may
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be configured to accept fasteners that may be configured to flex to a greater
degree than the
contacted surface area of the mating indents.
[0067] As indicated above, FIGS. 1 and 2 describe an example wind turbine
operating
environment in which the torque reacting joint of the wind driven power system
may be used.
However, the torque reacting joint is not limited for use in wind turbines,
and may also be used
in other power transmission applications.
[0068] FIGS. 12-13E show additional embodiments of the present invention,
directed to a
wind driven power generation system comprising a gearbox having a gear-train
(including an
input and an output) and a rotating conduit internally traversing the gear-
train. The conduit is
part of a lubrication system of the wind driven power generation system. The
lubrication system
may internally direct oil to various components included in a gearbox of the
wind turbine,
thereby increasing the lubrication provided to the components, and decreasing
the likelihood of
rupturing an external lubrication line during installation and repair. The
disclosed lubrication
system is described with regard to a wind turbine. However, it can be
appreciated that the
lubrication system may be applied to other suitable gearboxes outside of the
wind energy sector,
such as gearboxes used in the mining industry. Before describing the
lubrication system in
detail, an operating environment in which the lubrication system may be used
is described with
regard to FIG. 12. (FIGS. 1 and 2 are also applicable.)
[0069] A more detailed illustration of an embodiment of a nacelle 16 is shown
in FIG. 12.
The nacelle 16 houses a power generation system 1210, allowing wind force to
be converted into
electrical energy. The power-generating system may include a gearbox 1212
having an input
and an output. The input may be coupled to, and may receive rotational input
from, the rotor
head 24. An input bearing 1213, such as a roller bearing, may be provided
within the nacelle,
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allowing a rotational input to be transferred to various components within the
gearbox. The input
may include a torque coupling, included in an input carrier, discussed in more
detail herein with
regard to FIG. 13. The gearbox may be configured to adjust the speed of a
rotational input from
the rotor head. Furthermore, the output of the gearbox may be coupled to a
generator 214 and
configured to convert mechanical energy from the output into electrical
energy. A suitable
output device, such as an output shaft 216, may couple the output of the
gearbox to the generator.
[0070] The generator 214 may be coupled to an electrical transmission system
(not shown),
which may be routed through the tower to the base of the wind turbine. Various
types of
generators may be used in the wind turbine, such as an induction type, wound
type, synchronous
type, secondary resistance control wound induction type (rotor current control
or RCC type),
secondary excitation control wound induction type (static Scherbius or D.F.
type), permanent
magnet type, induction multiple type, etc.
[0071] Moreover, a pitch control system 218 may be included in the nacelle.
The pitch
control system may include a controller 1220. In this example, the controller
may be coupled to
a rear portion of the gearbox. However, in other examples, the controller may
be located in
another suitable location, such as the bedplate of the nacelle. The controller
may include a
processing unit 1222, memory 1224 such as random access memory (RAM) and read
only
memory (ROM), and/or other suitable components.
[0072] Continuing with FIG. 12, stationary electrical wires 1228 may
electrically couple the
controller 1220 to a slip ring 1226, included in the pitch control system 218.
The slip ring may
be configured to transfer electricity from a stationary state into a rotating
state. In this way, the
slip ring may act as an interface between the stationary electrical wires 1228
and the rotating
electrical wires 1230. The rotating electrical wires may be enclosed by a
pitch tube 1232 or
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other suitable rotating conduits that internally traverse the gearbox.
Therefore various gears
included in the gearbox may be arranged around the pitch tube. Furthermore,
the pitch tube
and/or rotating electrical wires may rotate at the same speed as the rotor
head. Additionally, the
pitch tube may also contain a lubrication channel internally traversing the
gearbox, included in a
lubrication system, as discussed in more detail herein with regard to FIGS.
13A-13E. In other
examples, it can be appreciated that additional or alternate pitch control
lines, such as hydraulic
lines, may be directed through the pitch tube.
[0073] The rotating electrical wires 230 may be coupled to one or more pitch
control
mechanisms 234 located within the rotor head. The pitch control mechanisms may
be
configured to adjust the pitch of one or more rotor blades. In this way, the
rotor blades may be
adjusted to optimize the power output of the wind turbine.
[0074] FIG. 13A illustrates a schematic depiction of a differential planetary
gearbox 1310
having a central axis of rotation 1311, as part of an embodiment of the wind
driven power
generation system. The differential planetary gearbox 1310 may be utilized in
a power-
generating wind turbine, such as shown in FIGS. 1, 2, and 12. However, it can
be appreciated
that alternate gearboxes may be used in the power-generating wind turbine
illustrated in FIGS. 1,
2, and 12, such as a simple planetary gearbox, compound planetary gearbox,
etc. Additionally,
various gearboxes currently in production may be used, such as the GE Wind
Energy 2.5x1,
Fuhrlander FL2500, and/or Unison U88 and U93. The differential planetary
gearbox 1310 may
include a lubrication system 1336 configured to internally deliver oil to
various components
within the gearbox. In this way, oil may be effectively delivered to the
gearbox, increasing
lubrication and/or cooling in the gearbox, and avoiding potential degradation
of the lubrication
lines due to human error during installation, repair, etc. The lubrication
system and its various
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benefits are discussed in more detail herein. It can be appreciated that other
suitable lubrication
fluids may be used, such as synthetic oils, silicon based lubricants, or a
combination thereof.
[0075] The gearbox 1310 may include a gear-train 1312 at least partially
enclosed by a
housing 1313. The gear-train may include a torque coupling 1314 which may be
included in an
input carrier 1315. As discussed above, the wind driven rotor head may be
coupled to the torque
coupling through suitable attachment mechanisms, such as bolts, screws, etc.
An input bearing
1316, or bearing set, configured to facilitate rotation of the input carrier,
may be positioned on an
exterior surface 1318 of the input carrier. In some examples, the input
bearing may be a suitable
bearing, such as a tapered roller bearing, allowing the bearing to accept the
majority of the thrust,
axial, and bending loads, thereby eliminating the gearbox as a structural
member of the power-
generating wind turbine. It can be appreciated that other types of bearings
may be utilized such
as a double row tapered roller bearing, a non-tapered roller bearing, etc.
[0076] An upwind set of planet gears 1320 may be coupled to the input carrier
1315 through
planet pinions 1321. Herein, the input carrier may drive the upwind set of
planet gears in an
orbital rotation. It can be appreciated that a set may include one or more
components. The
upwind set of planet gears may include corresponding upwind planet bearings
1322 (or bearing
set). In this example, a fixed upwind ring gear 1324 may be coupled to the
upwind planet gears
through meshing engagement, directing the rotation of the upwind set of planet
gears. However,
in other examples, the upwind ring gear 1324 may not be included in the gear-
train.
Additionally, the upwind set of planet gears 1320 may be in meshing engagement
with a sun
gear 1326.
[0077] The input carrier 1315 may also be fixedly coupled to a downwind ring
gear 1328.
The downwind ring gear may be in meshing engagement with a downwind set of
planet gears
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1330. The downwind set of planet gears 1330 may also be in meshing engagement
with the sun
gear 1326. In some examples, the downwind set of planet gears 1330 and the
upwind set of
planet gears 1320 may be rotatably coupled. However, in other examples, the
downwind set of
planet gears and the upwind set of planet gears may not be rotatably coupled.
Further, in some
examples, at least a portion of the aforementioned meshing engagements in the
gear-train may be
helical. Each downwind planet gear may include a corresponding downwind planet
bearing (not
shown), facilitating rotation of the downwind set of planet gears.
[0078] Accordingly, the gearbox may include two power paths. A first power
path may
pass through the upwind set of planet gears 1320 and a second power path may
pass through the
downwind ring gear 1328. The upwind set of planet gears may drive the sun gear
1326 and the
downwind ring gear may drive the downwind set of planet gears 1330, which in
turn may drive
the sun gear. Therefore, both of the power paths pass through and recombine at
the sun gear
1326. By designing a gearbox with two power paths, the weight as well as the
size gearbox may
be reduced, allowing for a compact and efficient design.
[0079] Furthermore, the sun gear may be coupled to an output shaft 1332, which
may be
included in an output of the gearbox or gear-train. A rear bearing 1334 (or
bearing set) may be
coupled to the output shaft, facilitating rotation of the output shaft. In
some examples, the output
shaft may lead to a parallel stage shaft (not shown), which may be included in
the output of the
gearbox. However, in other examples, the output shaft may lead to another
suitable component
included in the output of the gearbox.
[0080] The gearbox may further include a lubrication system 1336 configured to
deliver oil
to various components included in the gearbox. The lubrication system may
include a rear
lubrication manifold 1338, which may be stationary, located in a rear portion
of the gearbox.
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[0081] Additionally, the rear lubrication manifold may be fluidly coupled to a
pump 1345.
The pump may be configured to increase the pressure of the oil in the
lubrication system, and
direct pressurized oil downstream into the rear lubrication manifold. In this
example, the pump
1345 is an electrical pump. However, it can be appreciated that other suitable
pumps may be
utilized. Furthermore, the pump may be coupled to additional components
included in the
lubrication system. The additional components may include a suitable
collection apparatus, such
as a sump 1346. The sump may collect oil from the gear-train and direct it
back to the rear
lubrication manifold through a return line 1347. In this way, oil may be
circulated through the
lubrication system. In this example, the sump and the return line are external
to the gearbox.
However, it can be appreciated that in other examples the sump and/or the
return line may be
internal components in the gearbox, preventing the line from being damaged or
ruptured during
installation or repair.
[0082] Additional components may be included in the lubrication system,
including a closed
loop cooling system (not shown) configured to remove heat from the oil.
Additionally or
alternatively, a filtering system (not shown) may be used to remove unwanted
contaminants from
the lubrication system. The filtering system may include one or more filters
having similar or
varying degrees of filtration. In this way, the wear on the gear-train may be
decreased by
removing unwanted particulates from the lubrication system, thereby increasing
the lifespan of
the wind turbine.
[0083] FIG. 13B illustrates an enlarged view of the rear lubrication manifold.
The rear
lubrication manifold 1338 may be configured to deliver oil to the rear bearing
1334 and/or other
suitable components included in the gear-train. The rear lubrication manifold
1338 may include
a feed line 1340, which may be stationary. In this example, the feed line is
radially positioned.
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However, in other examples, the position of the feed line 1340 may be adjusted
depending on
various design requirements. The feed line may be fluidly coupled to a first
and a second
downwind bearing lubrication line, 1341 and 1342 respectively. The first and
the second
downwind bearing lubrication lines may extend towards the rear bearings,
thereby providing the
rear bearing with oil. In this example, the diameter of the first and second
downwind lubrication
lines (1341 and 1342) may be smaller than the feed line 1340. However, it can
be appreciated
that in other examples the size, geometry, etc., of the first downwind
lubrication line, second
downwind lubrication line, and/or feed line may be altered. Further, in other
examples,
additional lubrication lines may be included in the rear lubrication manifold.
[0084] Continuing with FIG. 13B, a hydraulic union 1348, which may be
stationary, is
fluidly coupled to the rear lubrication manifold. The hydraulic union may be
configured to
transfer oil from the rear lubrication manifold to a rotating lubrication
channel 1349, surrounding
the pitch tube. In this example, the hydraulic union 1348 may extend around
the periphery of the
outer tube 1350. However, in other examples, the hydraulic union 1348 may only
extend around
a portion of the rotating conduit. The rotating lubrication channel may rotate
at the same speed
as the rotor head 24, illustrated in FIGS. 1, 2, and 12. Continuing with FIG.
13B, the rear
lubrication manifold and the rotating lubrication channel may rotate at
different speeds. Rotating
at different speeds includes one non-moving component and one rotating
component, for
example. Therefore, oil may be directed downstream into the rotating
lubrication channel from a
stationary component. The rotating lubrication channel may direct oil in an
axial (e.g. upwind)
direction to various components in the gearbox.
[0085] FIGS. 13C and 13D illustrate a detailed view of the rotating
lubrication channel
1349. An outer tube 1350, or other suitable rotating conduit, may surround at
least a portion of
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the pitch tube 1232, thereby forming a tube-in-tube assembly 1351. In this
example, the annulus
of the tube-in-tube assembly is the lubrication channel. It can be appreciated
that in other
examples other configurations are possible, such as a configuration in which
the pitch tube
surrounds the lubrication channel and a configuration in which the tubes are
not concentric.
Furthermore, the shape of the tubes may be cylindrical or may have another
suitable geometry.
[0086] In this example, the pitch tube 1232 and the outer tube 1350 rotate at
the same speed
and are joined through a suitable coupling apparatus, such as a slip coupling
(not shown).
However, in other examples, the pitch tube 1232 and the outer tube may rotate
at different
speeds. The pitch tube may form an inner channel 1352 housing various
electrical wires, as
discussed above, separated from the oil in the lubrication channel. Therefore,
oil may be
directed down the lubrication channel in an axial (e.g., upwind) direction to
various gearbox
components without interfering with the pitch control system.
[0087] Returning to FIG. 13A, various distribution manifolds may be fluidly
coupled to the
lubrication channel 1349, configured to deliver oil to various components
included in the
gearbox 1310. The distribution manifolds may include an intermediate
lubrication manifold
1360 as well as an upwind distribution manifold 1370. The intermediate
lubrication manifold
may include various lubrication lines configured to deliver oil to the gear
mesh between the
downwind set of planet gears 1330 and the sun gear 1326. The lubrication
lines, included in the
intermediate lubrication manifold, may extend in a radial direction away from
the lubrication
channel 1349.
[0088] FIG. 13E illustrates a detailed view of the upwind distribution
manifold 1370 as well
as various lubrication lines configured to deliver oil to various components
in the gear-train
1312, downstream of the pitch tube 1232, included in the upwind distribution
manifold. The
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upwind distribution manifold may rotate at the same speed as the tube-in-tube
assembly. The
lubrication lines may include bearing lubrication lines 1372 facilitating
delivery of oil to the
input bearing 1316 and/or the upwind planet bearings 1322. In some examples,
the bearing
lubrication lines 1372 may be routed through the input carrier 1315 via
internal plumbing.
However, in other examples, the bearing lubrication lines may be routed around
the input carrier.
In particular, the bearing lubrication lines may include a main conduit 1374
extending radially
away from the pitch tube. A first branch conduit 1376 may extend towards the
input bearing and
a second branch conduit 1378 may extend toward the upwind planet bearing. The
first branch
conduit 1376 may be coupled to an input bearing port 1380. The input bearing
port may direct
oil into the center of the bearing between two sets of rollers. The second
branch conduit 1378
may be coupled to an upwind planet bearing port 1382. The input bearing port
1380 and/or the
upwind planet bearing port 1382 may include nozzles, orifices, or other
suitable devices
configured to direct oil into various components.
[0089] Additionally, gear lubrication lines 1384 may be included in the upwind
distribution
manifold 1370, configured to deliver oil to the gear mesh between upwind set
planet gears 1320
and the sun gear 1326. The gear lubrication lines may include a main conduit
1386, first
extending radially away from the pitch tube, and then axially downwind. Three
gear ports, 1388,
1389, and 1390 respectively, may extend radially away from the main conduit
1386. A fourth
gear port 1392 may also be included in the upwind lubrication manifold. It can
be appreciated
that in other examples the geometry, size, and/or positioning of the upwind
distribution manifold,
bearing lubrication lines, etc., may be altered based on various parameters,
such as the
lubrication requirements, type of gearbox in use, etc. Also, the
aforementioned ports may
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include nozzles, orifices, or other suitable devices configured to direct oil
into various gearbox
components.
[0090] The various examples of the disclosed lubrication system allow external
lubrication
lines to be eliminated in the upwind portion of the gearbox, if desired.
Therefore, degradation
and possible rupture of the oil lines during installation or maintenance, due
to human error, may
be reduced. In this way, the longevity of the gearbox may be increased.
[0091] Other aspects of the present invention relate to a wind driven power
generation
system, e.g., for inclusion in a wind turbine having one or more wind driven
rotor blades,
embodiments of which are shown in FIGS. 14-19. The system comprises a
transmission
assembly 2310, which includes a transmission 2316 and a removable input
bearing cartridge
2312. The transmission 2316 comprises an input carrier 2314 and a gear-train
2318 rotatably
coupling the input carrier to a transmission output 2320. The input carrier
2314 is configured to
transfer a rotational input from the rotor blades 26 to the gear-train 2318.
The removable input
bearing cartridge 2312 is coupled to a periphery of the input carrier,
exterior to the gear-train,
and is in axial alignment with the input carrier. In this way, the removable
input bearing
cartridge may be installed subsequent to assembly of the transmission, thereby
increasing the
modularity of the transmission and allowing the transmission to be used in a
multitude of wind
turbine designs. Also, the installation and removal process is simplified,
decreasing the cost of
installation as well as repair.
[0092] The input bearing cartridge 2312 is removable, meaning it may be
installed and
removed from the transmission subsequent to assembly of the transmission.
Further, the
removable input bearing cartridge may include a suitable bearing such as a
tapered roller
bearing, allowing the bearing to accept the majority of the radial and axial
loads, from the rotor
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head and rotor blades. Therefore, the transmission of loads from the rotor
blades and rotor head
into the gear-train is substantially decreased or eliminated, allowing the
transmission assembly to
be used in a greater number of wind turbines, thereby increasing the
transmission assembly's
modularity. It can be appreciated that other types of bearings may be
utilized, such as a double
row tapered roller bearing, standard roller bearing, etc. Furthermore, due to
the location and
configuration of the input bearing cartridge, up-tower repair of both the
removable bearing
cartridge and the transmission can be performed, decreasing repair cost.
Various detailed
illustrations of various embodiments of the bearing cartridge are shown in
FIGS. 14-18,
discussed in greater detail herein. The illustrations in FIGS. 14-18 are drawn
approximately to
scale.
[0093] A number of suitable transmissions having an input and an output may be
utilized.
Specifically, in this example a differential planetary gearbox is utilized.
However, other suitable
transmissions may be utilized, such as gearboxes with axially aligned input
and output axes of
rotation, or gearboxes having parallel output shafts.
[0094] FIG. 14 shows a cut away side view of the transmission assembly 2310.
The
transmission assembly 2310 shown in FIG. 14 may be similar to the transmission
assembly 212
shown in FIG. 2. The transmission assembly 2310 includes the removable input
bearing
cartridge 2312, discussed in more detail herein with regard to FIGS. 16-18.
The removable input
bearing cartridge 2312 is coupled to the periphery of the input carrier 2314.
The removable
input bearing cartridge may be in axial alignment with the input carrier 2314.
The input carrier
2314 is included in a transmission 2316, which further comprises a gear-train
2318 rotatably
coupling the input carrier 2314 to the transmission output 2320. The input
carrier is upwind of
the transmission output 2320. In this example, the transmission is a planetary
gearbox having a
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central axis of rotation 2321. However, it can be appreciated that an
alternate suitable
transmission may be utilized.
[0095] The planetary gearbox may include a ring gear 2322, a plurality of
planet gears, and
a sun gear 2324. In this example, the input carrier 2314 is coupled to the
ring gear 2322 and a
first set of planet gears 2326, thereby driving the gear-train. However, it
can be appreciated that
alternate configurations are possible. The first set of planet gears 2326 may
be in meshing
engagement with the sun gear 2324. The ring gear 2322 may be in meshing
engagement with a
second set of planet gears 2327. Further, the second set of planet gears 2327
may be in meshing
engagement with the sun gear. The sun gear may be coupled to a central
rotating shaft 2328
rotating about the central rotating axis 2321. Additionally, the central
rotating shaft may be
coupled to the output 2320. Each of the meshing gear engagements, including
between the ring
gear and the planet gears, as well as between the planet gears and the sun
gear, may be a helical
meshing engagement.
[0096] Also, a pitch control tube 2330 is shown directed through the center of
the generator
and the transmission (e.g., through the rotor, transmission output, and
transmission input), along
the central rotating axis 2321. In this way, the pitch control tube traverses
from the transmission
input through the generator and is inside the center of the planetary
transmission. The pitch
control tube may include various conduits (not shown), such as electric wires
and/or hydraulic
lines, and is configured to adjust the orientation (e.g., pitch) of the rotor
blades. The conduits
may be coupled to a suitable controller (not shown) located in the rotor hub,
nacelle or at a
down-tower location. A torque tube 2334 may also be included in the gear-
train. The torque
tube may be configured to transfer torque from the input carrier to various
components included
in the gear-train.
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[0097] Further, it can be appreciated that alternate types of bearings may be
included in the
transmission (e.g., gearbox). For example, one or more planet bearings may be
included in the
gear-train for allowing the planet gears to orbitally rotate about the sun
gear. Additionally, a
bearing (not shown) may be included near the output to receive loads, thereby
supporting the
gear-train and/or generator. In this example, the input bearing serves as the
primary support for
the input carrier.
[0098] The design of the transmission assembly, in particular the design of
the input bearing
cartridge positioned exterior to the gear-train, simplifies the manufacturing,
installation, removal,
and repair process when compared to bearing used in prior art transmission
designs which
integrate the bearing into the gear-train. In this way, the cost of the
transmission assembly and
therefore of the wind turbine is decreased.
[0099] Lubrication may be provided to various components in the transmission
assembly,
such as the input bearing cartridge, decreasing the friction between the
components during
operation as well as dissipating the thermal energy produced in rotation. A
suitable lubricating
fluid such as high viscosity oil may be utilized.
[00100] FIG. 15 shows an isometric view of the transmission assembly 2310
including a
transmission housing 2410 surrounding at least a portion of the transmission.
[00101] Various detailed views of the input carrier 2314 and the bearing
cartridge 2312 are
shown in FIGS. 16-18. FIG. 16 shows a cut away view of an assembled bearing
cartridge and
input carrier. FIG. 18 shows an exploded view of the bearing cartridge and
input carrier. FIG.
17 shows an isometric view of an assembled bearing cartridge and input
carrier.
[00102] As shown in FIG. 18, the bearing cartridge 2312 may include two
bearing rows, an
upwind bearing row 2534 and a downwind bearing row 2536. Each of the bearing
rows may
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include an inner and an outer race, 2540 and 2538 respectively, at least
partially enclosing a
plurality of rollers 2542. In other examples, the bearing rows may include the
outer race and the
rollers. In this example, the rollers are cylindrical. However, in other
examples the rollers may
be spherical or conical. Each roller may have an axis of rotation 2544, as
shown in FIG. 16,
about which the rollers rotate during operation of the wind turbine. A spacer
2545 may be
interposed between the upwind bearing row 2534 and the downwind bearing row
2536, allowing
the loads on the bearing rows to be properly distributed.
[00103] The inner race 2540 may be coupled to an exterior surface 2546 of the
input carrier.
The outer race 2538 may be coupled to a portion of the transmission housing.
In this way, the
input bearing cartridge 2312 may allow the input carrier 2314 to rotate about
a central rotating
axis. A lubrication fluid, such as oil, may at least partially surround the
rollers, decreasing the
wear on the rollers and the inner and outer race. Additionally, a suitable
bearing spacer may be
interposed between the upwind bearing row and the downwind bearing row.
[00104] A bearing housing 2547, shown in FIGS. 16 and 18, may be included in
the input
bearing cartridge. The bearing housing 2547 is coupled to and at least
partially surrounds the
outer races. The bearing may be configured to couple to a stationary
transmission housing (not
shown) attached to the nacelle through a suitable coupling apparatus. In this
way, the bearing
housing and the outer races act as a stator. In other examples, the outer race
may include the
bearing housing. The bearing housing 2547 may include holes configured to
receive various
attachment mechanisms such as bolts, shoulder bolts, etc. The bolt holes may
be positioned such
that various components, for example the bearing cap discussed in greater
detail herein, may be
coupled to the bearing housing.
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[00105] In some examples, the bearing housing may contain at least a portion
of a lubrication
system 2548. The lubrication system may include one or more supply passage(s)
2549 and/or
one or more drain passage(s) (not shown). The supply passage(s) and/or drain
passage(s) may
extend through various components included in the bearing cartridge, such as
spacers, to provide
various rotating components in the bearing with lubrication fluid. It can be
appreciated that a
pump may be fluidly coupled to the supply passage(s) and/or the drain
passage(s) to provide
pressurized lubrication fluid.
[00106] Furthermore, the bearing rows 2534, 2536 may be tapered. A taper angle
of the
bearing cartridge may be the angle 2550 defined by the intersection of the
axis of rotation 2544
of one or more of the rollers 2542 included in a bearing row and a line 2551
substantially parallel
to the central axis of rotation 2321 of the transmission (e.g., input
carrier). A taper angle 2550,
defined by the intersection of an axis of rotation 2544 of a roller included
in the upwind row and
line 2551, is illustrated in FIG. 16. It can be appreciated that the downwind
row may also have a
taper angle, which may be substantially equivalent to the taper angle 2550 or
may be another
suitable angle.
[00107] As shown in FIG. 16, a stator shim 2554 may be coupled to the outer
race of the first
and second bearing rows using suitable coupling hardware 2552, such as bolts.
An extended
section 2556 of the stator shim may be configured to clamp the outer race of
the upwind row as
well as the bearing housing. The contacted surfaces of the stator shim and the
outer race mate to
form a static oil seal, preventing oil from leaking out of the input bearing
cartridge. A rotor shim
2558 is coupled to the input carrier and the upwind bearing row 2534. The
rotor shim may be
positioned to maintain a desired end play for the input carrier. An additional
coupling apparatus
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(not shown) may be attached to the rotor shim and the input carrier for
clamping the rotor shim
to the input carrier.
[00108] The input bearing cartridge 2312 is configured to axially and radially
support the
input carrier 2314. Support may include receiving at least a portion of the
loads generated by or
transferred to a component. Due to the configuration of the transmission
assembly loads from
the rotor head, main shaft, and/or the transmission, shown in FIGS. 1 and 2,
may be transferred
to the input carrier. Additionally, the input bearing cartridge allows the
input carrier to rotate.
Consequently, during operation of the wind turbine, the input carrier may
receive rotational input
from the main shaft 20, shown in FIGS. 1 and 2, and initiate rotation of the
gear-train, thereby
initiating electrical power generation in the wind turbine. The input bearing
cartridge may
receive the majority of the loads generated by the wind (i.e., loads from the
rotor head) through
the input carrier. Consequently, the wind loads from the rotor blades and
rotor head are not
translated to the gear-train included in the transmission, decreasing the wear
on the gear-train.
Thus, the gear-train may be used in numerous wind turbines having different
designs.
[00109] The input carrier 2314 may include a coupling interface 2562, as shown
in FIG. 17,
configured to couple the input carrier to the main shaft. The coupling
interface may be
configured to couple to the main shaft by suitable coupling hardware (not
shown), such as bolts
extending through bored holes 2564. Additionally, a bearing cap 2566, shown in
FIG. 17, may
be coupled to the bearing housing 2547 using hardware 2568. The bearing cap
prevents
unwanted particulates from entering the input bearing cartridge and acts as a
seal for lubrication.
In some examples, the coupling interface may be upwind of the input bearing
cartridge. In other
examples, the coupling interface may be positioned at another suitable
location.
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[00110] Various design features of the input bearing cartridge, such as the
taper angle, may
be adjusted based upon the design specification of the rotor head, nacelle,
etc. Additionally, the
bearing settings may also be adjusted to meet specific design requirements.
The bearing settings
include at least one of the following: the position of the bearing rows, the
input bearing cartridge
position, the position of one or more shims, and/or the spacer size and/or
position. Thus, the
transmission may be adapted for use in a multitude of wind turbine designs,
decreasing the cost
of manufacturing. The design specifications of the rotor head include static
and dynamic loading
characteristics. For example, the tapered angle may be increased to account
for increased thrust
load on the bearing.
[00111] FIG. 19 illustrates a method 2800 for manufacturing a transmission
assembly. The
transmission assembly may include an input carrier, an output shaft, and a
plurality of gears
included in a gear-train of a transmission. The gear-train is configured to
increase the rotational
speed of the output shaft. In some examples, the transmission assembly is a
planetary gearbox
assembly. The disclosed method may be used to manufacture the transmission
assembly 2310,
shown in FIGS. 14-18, utilizing the components discussed above. Alternatively,
the disclosed
method may be used to manufacture another suitable transmission assembly.
[00112] First, at 2810, the method includes assembling an input carrier,
gears, and an output
forming a transmission, with the transmission having a central rotating axis.
Assembling the
gear-train may include assembling the gears and associated bearings, such as
planet gear
bearings, into an input carrier, at 2810A. The gears may include a plurality
of planet gears, a
ring gear, and a sun gear. Optionally, assembling the gear-train may include
assembling the
torque tube onto the input carrier, at 2810B. In some examples, the gear-train
may be assembled
in a separate facility or location.
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[00113] Optionally, at 2812 the method may include coupling an inner bearing
race to the
input carrier. In other examples, the inner bearing race may be included in
the input bearing
cartridge.
[00114] At 2814, the method includes assembling an input bearing cartridge.
Assembling
the input bearing cartridge may include at 2814A positioning a plurality of
rollers within an outer
race of a first and/or a second bearing row. It can be appreciated that in
some examples the input
bearing cartridge may include a single bearing row. Also, at 2814B the method
may include
attaching a torque tube onto the input carrier. Additionally, at 2814C the
method may include
positioning a spacer between the first and second bearing rows. Further, in
some examples the
method may include installing one or more bearing cups, as at 2814D.
[00115] At 2816 the method includes installing the input bearing cartridge on
a peripheral or
exterior portion of the input carrier. Installing may include coupling.
Suitable assembly
hardware, such as bolts, may be used to install the input bearing cartridge on
the input carrier. In
some examples, installing the input bearing cartridge to the input carrier may
include coupling a
bearing cap to a stator shim and/or coupling a rotor shim to an inner race, at
2816A. In this way
a lubrication seal may be formed, impeding lubrication fluid, such as oil,
from exiting the input
bearing cartridge, sealing the input bearing cartridge. Additionally,
installing the input bearing
cartridge may include adjusting the bearing cartridge settings at 2816B. The
bearing settings
may include the positioning of various components included in the input
bearing cartridge to
allow loads on the bearing to be properly distributed, decreasing the wear on
the input bearing
cartridge during operation. Further in some examples, installing the input
bearing cartridge may
include installing one or more bearing cones through suitable coupling
hardware.
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[00116] In some examples the method may include rotating the transmission
assembly with
the torque tube, at 2818. The rotation may include 180 of rotation. Next, at
2820, the method
may include positioning the transmission assembly within a transmission
housing, forming a
transmission assembly. The method may further include removing the input
bearing cartridge
from the transmission assembly and repairing or replacing the input bearing
cartridge. This may
occur subsequent to on site construction of a wind turbine when maintenance
may be needed.
Also, the removal of the input bearing cartridge may occur at an up-tower
location.
[00117] Even if not explicitly enumerated herein, any of the aforementioned
embodiments,
features, and elements of the wind driven power generation system may be
combined with any of
the other embodiments, features, and elements of the wind driven power
generation system,
within the spirit and scope of the present invention. For example, in one
embodiment, a wind
turbine (e.g., FIG. 1) includes a transmission assembly (with removable input
bearing cartridge),
a transmission (with torque reacting joint), and a gearbox (with lubrication
system) as described
above. The gearbox includes a first gear-train and a rotating conduit, which
is configured to
receive lubrication fluid from downstream of the rotating conduit and deliver
lubrication fluid
upstream of the rotating conduit. Components downstream of the rotating
conduit rotate at a
different speed than upstream components. The transmission includes a second
gear-train
enclosed by an outer housing. The outer housing includes a torque reacting
joint coupling a first
section of the transmission to a second section of the outer housing. The
transmission assembly
includes a transmission (comprising an input carrier and a gear-train
rotatably coupling the input
carrier to a transmission output) and a removable input bearing cartridge. The
removable input
bearing cartridge is coupled to a periphery of the input carrier, exterior to
the gear-train, in axial
alignment with the input carrier.
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[00118] It is to be understood that the above description is intended to be
illustrative, and not
restrictive. For example, the above-described embodiments (and/or aspects
thereof) may be used
in combination with each other. In addition, many modifications may be made to
adapt a
particular situation or material to the teachings of the invention without
departing from its scope.
While the dimensions and types of materials described herein are intended to
define the
parameters of the invention, they are by no means limiting and are exemplary
embodiments.
Many other embodiments will be apparent to those of skill in the art upon
reviewing the above
description. The scope of the invention should, therefore, be determined with
reference to the
appended claims, along with the full scope of equivalents to which such claims
are entitled. In
the appended claims, the terms "including" and "in which" are used as the
plain-English
equivalents of the respective terms "comprising" and "wherein." Moreover, in
the following
claims, the terms "first," "second," and "third," etc. are used merely as
labels, and are not
intended to impose numerical requirements on their objects. Further, the
limitations of the
following claims are not written in means-plus-function format and are not
intended to be
interpreted based on 35 U.S.C. 112, sixth paragraph, unless and until such
claim limitations
expressly use the phrase "means for" followed by a statement of function void
of further
structure.
[00119] This written description uses examples to disclose several embodiments
of the
invention, including the best mode, and also to enable any person skilled in
the art to practice the
embodiments of invention, including making and using any devices or systems
and performing
any incorporated methods. The patentable scope of the invention is defined by
the claims, and
may include other examples that occur to those skilled in the art. Such other
examples are
intended to be within the scope of the claims if they have structural elements
that do not differ
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from the literal language of the claims, or if they include equivalent
structural elements with
insubstantial differences from the literal languages of the claims.
[00120] As used herein, an element or step recited in the singular and
proceeded with the
word "a" or "an" should be understood as not excluding plural of said elements
or steps, unless
such exclusion is explicitly stated. Furthermore, references to "one
embodiment" of the present
invention are not intended to be interpreted as excluding the existence of
additional embodiments
that also incorporate the recited features. Moreover, unless explicitly stated
to the contrary,
embodiments "comprising" or "having" an element or a plurality of elements
having a particular
property may include additional such elements not having that property.
[00121] Since certain changes may be made in the above-described wind driver
power
generation system, without departing from the spirit and scope of the
invention herein involved,
it is intended that all of the subject matter of the above description or
shown in the
accompanying drawings shall be interpreted merely as examples illustrating the
inventive
concept herein and shall not be construed as limiting the invention.
