U.S. patent application number 12/963159 was filed with the patent office on 2011-10-06 for joint sleeve for a rotor blade assembly of a wind turbine.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Eric Lee Bell.
Application Number | 20110243736 12/963159 |
Document ID | / |
Family ID | 44709893 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110243736 |
Kind Code |
A1 |
Bell; Eric Lee |
October 6, 2011 |
JOINT SLEEVE FOR A ROTOR BLADE ASSEMBLY OF A WIND TURBINE
Abstract
A joint sleeve for assembling together a first blade section and
a second blade section of a rotor blade assembly is disclosed. The
joint sleeve may include an outer surface and an inner surface
defining a cavity. The cavity may be configured to receive a joint
end of the first blade section and a joint end of the second blade
section. The joint sleeve may also include a plurality of openings
defined between the outer and inner surfaces. The openings may be
configured to receive fasteners for securing the joint ends of the
first and second blade sections within the cavity. Additionally, a
profile of the outer surface may be configured to generally
correspond to an aerodynamic profile of the first and second blade
sections such that a substantially continuous aerodynamic profile
is defined between the first and second blade sections when the
joint ends are inserted within the cavity.
Inventors: |
Bell; Eric Lee; (Greenville,
SC) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
44709893 |
Appl. No.: |
12/963159 |
Filed: |
December 8, 2010 |
Current U.S.
Class: |
416/132R |
Current CPC
Class: |
F03D 1/0683 20130101;
F05B 2240/307 20200801; F05B 2240/302 20130101; F05B 2250/292
20130101; F05B 2260/301 20130101; F03D 1/0675 20130101; Y02E 10/72
20130101 |
Class at
Publication: |
416/132.R |
International
Class: |
F04D 29/18 20060101
F04D029/18 |
Claims
1. A rotor blade assembly for a wind turbine, the rotor blade
assembly comprising: a first blade section including a joint end
and defining an aerodynamic profile; a second blade section
including a joint end and defining an aerodynamic profile; a joint
sleeve having an inner surface and an outer surface, the inner
surface defining a cavity configured to receive the joint ends of
the first and second blade sections; and, a plurality of fasteners
configured to secure the joint ends of the first and second blade
sections within the cavity, wherein a profile of the outer surface
of the joint sleeve generally corresponds to the aerodynamic
profiles of the first and second blade sections such that a
substantially continuous aerodynamic profile is defined between the
first and second blade sections when the joint ends are inserted
within the cavity.
2. The rotor blade assembly of claim 1, wherein the second blade
section is configured as a tip section of the rotor blade
assembly.
3. The rotor blade assembly of claim 2, wherein the tip section
defines a winglet.
4. The rotor blade assembly of claim 1, wherein a tapered profile
is defined at the joint ends of the first and second blade
sections, the joint sleeve defining a tapered width generally
corresponding to the tapered profile.
5. The rotor blade assembly of claim 1, wherein a stepped profile
is defined at the joint ends of the first and second blade
sections.
6. The rotor blade assembly of claim 1, wherein the plurality of
fasteners comprises a plurality of threaded fasteners.
7. The rotor blade assembly of claim 6, further comprising a
plurality of threaded members disposed at the joint ends of the
first and second blade sections, the plurality of threaded members
being configured to receive the plurality of threaded
fasteners.
8. The rotor blade assembly of claim 1, further comprising a
plurality of openings defined between the inner and outer surfaces
of the joint sleeve, each of the plurality of openings defining a
recessed feature configured to recess the plurality of fasteners
within the joint sleeve.
9. The rotor blade assembly of claim 1, further comprising a
divider configured to separate the joint ends of the first and
second blade sections within the cavity.
10. A joint sleeve for assembling together a first blade section
and a second blade section of a rotor blade assembly, the sleeve
comprising: an outer surface; an inner surface defining a cavity,
the cavity having a root end configured to receive a joint end of
the first blade section and a tip end configured to receive a joint
end of the second blade section; and, a plurality of openings
defined between the outer and inner surfaces, the plurality of
openings being configured to receive a plurality of fasteners for
securing the joint ends of the first and second blade sections
within the cavity, wherein a profile of the outer surface is
configured to generally correspond to an aerodynamic profile of the
first and second blade sections such that a substantially
continuous aerodynamic profile is defined between the first and
second blade sections when the joint ends are inserted within the
cavity.
11. The joint sleeve of claim 10, wherein a tapered width is
defined between the outer and inner surfaces.
12. The joint sleeve of claim 10, wherein each of the plurality of
openings defines a recessed feature between the outer and inner
surfaces.
13. The joint sleeve of claim 10, further comprising a divider
configured to separate the joint ends of the first and second blade
sections within the cavity.
14. The joint sleeve of claim 10, wherein the divider extends
substantially perpendicularly from the inner surface.
15. The joint sleeve of claim 10, wherein an aerodynamic profile of
the root end generally corresponds to the aerodynamic profile of
the first blade section and an aerodynamic profile of the tip end
generally corresponds to the aerodynamic profile of the second
blade section.
16. A tip assembly for a rotor blade of a wind turbine, the tip
assembly comprising: a joint sleeve including an inner surface
defining a cavity and an outer surface defining an aerodynamic
profile, the joint sleeve further including a tip end and a root
end, a tip section extending between a joint end and a blade tip
and defining an aerodynamic profile generally corresponding to the
aerodynamic profile of the joint sleeve at the tip end, the joint
end of the tip section being disposed within the cavity; and, a
plurality of fasteners configured to secure the joint end of the
tip section within the cavity, wherein a portion of the cavity
disposed at the root end of the joint sleeve is configured to
receive an end of a separate section of the rotor blade.
17. The tip assembly of claim 16, wherein the tip section defines a
winglet.
18. The tip assembly of claim 16, wherein a tapered profile is
defined at the joint end of the tip section, the joint sleeve
defining a tapered width generally corresponding to the tapered
profile.
19. The tip assembly of claim 16, further comprising a plurality of
openings defined along the tip end of the joint sleeve and
configured to receive the plurality of fasteners, each of the
plurality of openings defining a recessed feature configured to
recess the plurality of fasteners within the joint sleeve.
20. The tip assembly of claim 16, further comprising a plurality of
openings defined along the root end of the joint sleeve, the
plurality of openings being configured to receive a plurality of
fasteners for securing the end of the separate section of the rotor
blade within the cavity.
Description
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to rotor blades
of a wind turbine and, more particularly, to a joint sleeve for
joining blade sections of a rotor blade assembly.
BACKGROUND OF THE INVENTION
[0002] Wind power is considered one of the cleanest, most
environmentally friendly energy sources presently available, and
wind turbines have gained increased attention in this regard. A
modern wind turbine typically includes a tower, generator, gearbox,
nacelle, and one or more rotor blades. The rotor blades capture
kinetic energy from wind using known foil principles and transmit
the kinetic energy through rotational energy to turn a shaft
coupling the rotor blades to a gearbox, or if a gearbox is not
used, directly to the generator. The generator then converts the
mechanical energy to electrical energy that may be deployed to a
utility grid.
[0003] To ensure that wind power remains a viable energy source,
efforts have been made to improve the overall performance of wind
turbines by modifying the size, shape and configuration of wind
turbine rotor blades. One such modification has been to alter the
configuration of the tip of the rotor blade. In particular, blade
tips may be specifically designed to enhance or improve various
aspects of a rotor blade's performance. For example, certain blade
tips may be designed to operate efficiently in specific wind
classes. Additionally, blade tips may be configured to enhance
specific operating conditions of the wind turbine, such as by being
configured to lower torque or reduce noise.
[0004] Thus, given that different operating advantages may be
provided to a wind turbine depending on the configuration of the
blade tip, it would be advantageous to have an attachment device
that allowed for the quick and efficient assembly and disassembly
of blade tips on and from a rotor blade. However, known attachment
devices are typically complex and are manually intensive to
install. Additionally, such attachment devices make it difficult to
accurately align the blade tip with the remainder of the rotor
blade.
[0005] Accordingly, there is a need for a simple and efficient
attachment device for joining two blade sections of a rotor blade
assembly.
BRIEF DESCRIPTION OF THE INVENTION
[0006] Aspects and advantages of the invention will be set forth in
part in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0007] In one aspect, the present subject matter discloses a rotor
blade assembly for a wind turbine. The rotor blade assembly
generally includes a first blade section having a joint end and
defining an aerodynamic profile and a second blade section having a
joint end and defining an aerodynamic profile. The rotor blade
assembly also includes a joint sleeve having an inner surface and
an outer surface. The inner surface may generally define a cavity
configured to receive the joint ends of the first and second blade
sections. Additionally, the rotor blade assembly may include a
plurality of fasteners configured to secure the joint ends of the
first and second blade sections within the cavity. Further, a
profile of the outer surface of the joint sleeve may generally
correspond to the aerodynamic profiles of the first and second
blade sections such that a substantially continuous aerodynamic
profile is defined between the first and second blade sections when
the joint ends are inserted within the cavity.
[0008] In another aspect, the present subject matter discloses a
joint sleeve for assembling together a first blade section and a
second blade section of a rotor blade assembly. The joint sleeve
may include an outer surface and an inner surface defining a
cavity. The cavity may have a root end configured to receive a
joint end of the first blade section and a tip end configured to
receive a joint end of the second blade section. The joint sleeve
may also include a plurality of openings defined between the outer
and inner surfaces. The openings may be configured to receive a
plurality of fasteners for securing the joint ends of the first and
second blade sections within the cavity. Additionally, a profile of
the outer surface may be configured to generally correspond to an
aerodynamic profile of the first and second blade sections such
that a substantially continuous aerodynamic profile is defined
between the first and second blade sections when the joint ends are
inserted within the cavity.
[0009] In a further aspect, the present subject matter discloses a
tip assembly for a rotor blade of a wind turbine. The tip assembly
may generally include a joint sleeve having an inner surface
defining a cavity and an outer surface defining an aerodynamic
profile. The joint sleeve may also include a tip end and a root
end. The tip assembly may also include a tip section extending
between a joint end disposed within the cavity and a blade tip. The
tip section may define an aerodynamic profile generally
corresponding to the aerodynamic profile of the joint sleeve at the
tip end. Additionally, tip assembly may include a plurality of
fasteners configured to secure the joint end of the tip section
within the cavity. Further, a portion of the cavity disposed at the
root end of the joint sleeve may be configured to receive an end of
a separate section of the rotor blade.
[0010] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended figures, in which:
[0012] FIG. 1 illustrates a perspective view of a wind turbine of
conventional construction;
[0013] FIG. 2 illustrates a perspective view of one embodiment of a
rotor blade assembly in accordance with aspects of the present
subject matter;
[0014] FIG. 3 illustrates a partial, perspective view of the rotor
blade assembly shown in FIG. 2;
[0015] FIG. 4 illustrates a perspective view of one embodiment of a
joint sleeve suitable for use with the disclosed rotor blade
assembly in accordance with aspects of the present subject
matter;
[0016] FIG. 5 illustrates a partial, cross-sectional view of one
embodiment of the attachment of several components of the disclosed
rotor blade assembly in accordance with aspects of the present
subject matter;
[0017] FIG. 6 illustrates a partial, cross-sectional view of
another embodiment of the attachment of several components of the
disclosed rotor blade assembly in accordance with aspects of the
present subject matter; and,
[0018] FIG. 7 illustrates a perspective view of an embodiment of a
tip assembly in accordance with aspects of the present subject
matter.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0020] In general, the present subject matter is directed to a
joint sleeve for joining together blades sections of a rotor blade
assembly. In particular, the joint sleeve may define a cavity
configured to receive an end of each blade section. For example,
the cavity may generally have a shape corresponding to the shape of
the ends of the blade sections, such as by having a tapered,
aerodynamic profile corresponding to the tapered, aerodynamic
profiles of the blade section ends. Suitable fasteners may then be
inserted around the periphery of the joint sleeve to secure the
ends of the blade sections within the cavity.
[0021] The disclosed joint sleeve may generally provide for the
quick and efficient assembly and disassembly of a rotor blade. As
such, a blade section may be easily removed from and re-assembled
onto the rotor blade for purposes of maintenance, repairs and/or
for upgrading the performance of the rotor blade. For example, it
may be preferable to vary the tip section of the rotor blade
depending on the wind turbine operating conditions and/or the
desired performance of the rotor blade assembly. Thus, by using the
disclosed joint sleeve, tip sections having differing dimensions,
configurations and/or aerodynamic features may be efficiently
assembled onto the rotor blade and/or replaced as desired. For
example, a straight tip section (e.g., a tip section extending in a
substantially spanwise direction) may be replaced with a
winglet-type tip section or vice versa. Similarly, a winglet having
a particular configuration may be replaced with a winglet having a
different configuration.
[0022] Referring now to the drawings, FIG. 1 illustrates
perspective view of a wind turbine 10 of conventional construction.
The wind turbine 10 includes a tower 12 with a nacelle 14 mounted
thereon. A plurality of rotor blades 16 are mounted to a rotor hub
18, which is, in turn, connected to a main flange that turns a main
rotor shaft. The wind turbine power generation and control
components are housed within the nacelle 14. It should be
appreciated that the wind turbine 10 of FIG. 1 is provided for
illustrative purposes only to place the present subject matter in
an exemplary field of use. Thus, one of ordinary skill in the art
should readily appreciate that the scope of the present subject
matter is not limited to any particular type of wind turbine
configuration.
[0023] Referring now to FIGS. 2-4, embodiments of a rotor blade
assembly 100 and a joint sleeve 102 for joining together first and
second blade sections 104, 106 of the rotor blade assembly 100 are
illustrated in accordance with aspects of the present subject
matter. In particular, FIG. 2 illustrates a perspective view of one
embodiment of the rotor blade assembly 100. FIG. 3 illustrates a
partial, perspective view of the rotor blade assembly 100
illustrated in FIG. 2, particularly illustrating the joint sleeve
102 disposed between the blade sections 104, 106 of the rotor blade
assembly 100. Additionally, FIG. 4 illustrates a perspective view
of one embodiment of the joint sleeve 102.
[0024] As shown, the rotor blade assembly 100 includes a first
blade section 104, a second blade section 106 and a joint sleeve
102 configured to join the blade sections 104, 106 together. In
general, the rotor blade assembly 100 may be configured such that,
when the first and second blade sections 104, 106 are attached
within the joint sleeve 102, a complete rotor blade, defining a
substantially aerodynamic profile, is formed. Thus, the complete
rotor blade assembly 100 may generally include a blade root 108
(defined by the first blade section 104) configured to be mounted
to the hub 18 (FIG. 1) of a wind turbine 10 and blade tip 110
(defined by the second blade section 106) disposed opposite the
blade root 108. The rotor blade assembly 100 may also include a
span 112 defining the total length between the blade root 108 and
the blade tip 110 and a chord 114 defining the total length between
the leading edge 116 and the trailing edge 118. As is generally
understood, the chord 114 may vary in length with respect to the
span 112 as the rotor blade extends from the blade root 108 to the
blade tip 110.
[0025] In general, the first and second blade sections 104, 106 of
the rotor blade assembly 100 may be configured similarly to any
suitable blade section and/or blade segment known in the art. For
example, each blade section 104, 106 may include a body shell 120
serving as the outer casing/covering of the blade section 104, 106
and one or more structural components (not shown) for providing
stiffness and/or strength to the blade section 104, 106 (e.g., a
shear web/spar cap assembly). Additionally, each blade section 104,
106 may generally define an aerodynamic profile. For instance, the
body shells 120 of each blade section 104, 106 may be configured to
define an airfoil shaped cross-section, such as a symmetrical or
cambered airfoil shaped cross-section. Thus, as shown in FIG. 3,
each body shell 120 may generally define a pressure side 122, and a
suction side 124 extending between a leading edge 126 and trailing
edge 128.
[0026] It should be appreciated that the body shells 120 may
generally be formed from any suitable material. For instance, in
one embodiment, each body shell 120 may be formed entirely from a
laminate composite material, such as a carbon fiber-reinforced
composite or a glass fiber-reinforced composite. Alternatively, one
or more portions of each body shell 120 may be configured as a
layered construction and may include a core material, formed from a
lightweight material such as wood (e.g., balsa), foam (extruded
polystyrene foam) or a combination of such materials, disposed
between layers of laminate composite material.
[0027] Additionally, the first and second blade sections 104, 106
may each include a joint end 130, 131 terminating within the joint
sleeve 102. Thus, in the illustrated embodiment, the first blade
section 104 may generally extend from the blade root 108 of the
rotor blade assembly 100 to its joint end 130 within the joint
sleeve 102. Similarly, the second blade section 102 may generally
extend from its joint end 131 within joint sleeve 102 to the blade
tip 110 of the rotor blade assembly 100. Further, as will be
described in greater detail below with reference to FIGS. 5 and 6,
the joint ends 130, 131 of the blade sections 104, 106 may define a
particular profile in order to facilitate insertion of the joint
ends 130, 131 within the joint sleeve 102. For instance, in several
embodiments, the joint ends 130, 131 of each blade section 104, 106
may define a tapered or stepped profile corresponding to a tapered
or stepped profile defined in the joint sleeve 102.
[0028] Moreover, as shown in FIGS. 2 and 3, the first blade section
104 may generally extend lengthwise along a substantial portion of
the span 112 of the rotor blade assembly 100 such that the joint
sleeve 102 is disposed at an outboard position on the rotor blade
generally proximate to the blade tip 110. As such, the second blade
section 106 may generally be configured as an outboard or tip
section of the rotor blade assembly 100. Thus, in the illustrated
embodiment, the second blade section 106 may be configured
similarly to the outboard portion of a conventional rotor blade 16
(FIG. 1), such as by extending in a substantially spanwise
direction between the joint end 131 of the blade section 106 and
the blade tip 110. Alternatively, as will described below with
reference to FIG. 7, the second blade section 106 may be configured
as a winglet-type tip section or may otherwise have any other
suitable tip configuration know in the art.
[0029] It should be appreciated that, in embodiments in which the
second blade section 106 is configured as an outboard or tip
section of the rotor blade assembly 100, the second blade section
106 may generally define a relatively short length 132. For
example, in several embodiments, the second blade section 106 may
define a length 132 which is less than 10 meters (m) long, such as
less than 5 m long or less than 3 m long and all other subranges
therebetween. However, in alternative embodiments, the second blade
section 106 need not be configured as a tip section of the rotor
blade assembly 100 and, thus, may generally define any suitable
length 132, such as a length greater than or equal to 10 m. In such
embodiments, it should be appreciated that the joint sleeve 102 may
generally be disposed at any suitable location along the span 112
of the rotor blade assembly 100, such as by being located at a more
inboard position closer to the blade root 108.
[0030] Still referring to FIGS. 2-4, the joint sleeve 102 of the
disclosed rotor blade assembly 100 may generally be configured as
an attachment device for joining the first and second blade
sections 104, 106. Thus, it should be appreciated that the joint
sleeve 102 may generally have any suitable configuration that
permits the joint ends 130, 131 of the blade sections 104, 106 to
be received within the joint sleeve 102. For example, in several
embodiment, the joint sleeve 102 may have a hollow or a
substantially hollow configuration for receiving the joint ends
130, 131 of the blade sections 104, 106. In particular, as shown in
FIG. 4, the joint sleeve 102 may generally include an inner
perimeter or inner surface 134 defining a cavity 136 extending
between a root end 138 and a tip end 140 of the joint sleeve 102.
As such, the joint end 130 of the first blade section 104 may be
configured to be received within the portion of the cavity 136
defined at the root end 138 of the joint sleeve 102 and the joint
end 131 of the second blade section 106 may be configured to be
received within the portion of the cavity 136 defined at the tip
end 140 of the joint sleeve 102.
[0031] It should be appreciated that the joint ends 130, 131 of the
blade sections 104, 106 may generally be attached within the cavity
136 of the joint sleeve 102 using any suitable means. For example,
in one embodiment, the joint ends 130, 131 may be bonded within the
joint sleeve 102 using any suitable adhesive. In another
embodiment, a plurality of fasteners 142 may be utilized to secure
the joint ends 130, 131 within the joint sleeve 102. For example,
as shown in FIGS. 3 and 4, the joint sleeve 102 may define a
plurality of openings 144 extending between its inner and outer
surfaces 134, 146, with each opening 144 being configured to
receive a fastener 142. Specifically, a plurality of openings 144
may be defined proximate to the root end 138 of the joint sleeve
102 to permit a like number of fasteners 142 to be inserted through
the openings 144 and attached to the joint end 130 of the first
blade section 104. Similarly, a plurality of openings 144 may be
defined proximate the tip end 140 of the joint sleeve 102 to permit
a like number of fasteners 142 to be inserted through the openings
144 and attached to the joint end 131 of the second blade section
106. It should be readily appreciated that the openings 144 may be
defined in the joint sleeve 102 so as to form any suitable bolt
hole pattern. For example, in one embodiment, the openings 144 may
form a single row along the root and tips ends 138, 140 of the
joint sleeve 102. In another embodiments, multiple rows (e.g., two
or more rows) of openings 144, being aligned or offset from one
another, may be defined in the root and tip ends 138, 140 of the
joint sleeve 102.
[0032] It should also be appreciated that the fasteners 142
described herein may generally comprise any suitable fasteners
known in the art. For example, in several embodiments, the
fasteners 142 may be configured as threaded fasteners, such as
threaded bolts, screws and other suitable threaded fastening
devices. In other embodiments, the fasteners may comprise other
suitable fastening and/or attachment devices, such as pins, clips,
brackets, rods, rivets, bonded fasteners and the like.
[0033] The disclosed joint sleeve 102 may also define a
substantially aerodynamic profile. For example, as shown in FIG. 4,
the joint sleeve 102 may define an airfoil-shaped cross-section.
Thus, similar to the first and second blade sections 104, 106, the
outer surface 146 of the joint sleeve 102 may generally define a
pressure side 148 and a suction side 150 extending between a
leading edge 152 and a trailing edge 152. Additionally, in several
embodiments of the present subject matter, the aerodynamic profile
defined by the joint sleeve 102 may generally correspond to or
otherwise match the aerodynamic profiles of the first and second
blade sections 104, 106. In particular, the aerodynamic profile of
the joint sleeve 102 at the root end 138 may generally correspond
to the aerodynamic profile of the first blade section 102 in an
area adjacent to its joint end 130. Similarly, the aerodynamic
profile of the joint sleeve 102 at the tip end 140 may generally
correspond to the aerodynamic profile of the second blade section
106 in an area adjacent to its joint end 131. As such, when the
blade sections 104, 106 are assembled together within joint sleeve
102, the rotor blade assembly 100 may generally define a
substantially continuous aerodynamic profile along its entire span
112. For instance, as shown in FIG. 3, the joint sleeve 102 may be
configured such that a substantially flush, aerodynamic surface is
defined at the interface of the first blade section 104 and the
root end 138 of the joint sleeve 102 and at the interface of the
second blade section 106 and the tip end 140 of the joint sleeve
102. Thus, the rotor blade assembly 100 may generally define a
continuous aerodynamic surface between the first and second blade
sections 104, 106.
[0034] It should be appreciated that, in several embodiments, an
additional surface feature may be applied to or positioned over the
seams formed at the interfaces of the blade sections 104, 106 and
the ends 138, 140 of the joint sleeve 102 to ensure that a
substantially smooth aerodynamic surface is achieved. For example,
in a particular embodiment, several plies of a laminate composite
material may be applied around the outer perimeter of the rotor
blade assembly 100 at the joint seams, such as by using a wet
lay-up process, to provide a substantially flush aerodynamic
surface between the blade sections 104, 106 and the joint sleeve
102.
[0035] It should also be appreciated that the joint sleeve 102 may
generally be formed from any suitable material. For example, in one
embodiment, the joint sleeve 102 may be formed from a metal, such
as aluminum, steel and the like. In other embodiments, the joint
sleeve 102 may be formed from a laminate composite material, such
as various fiber-reinforced composites, or any other suitable
non-metallic material.
[0036] Referring now to FIGS. 5 and 6, there is illustrated
partial, cross-sectional views of two embodiments of the disclosed
rotor blade assembly 100, particularly illustrating the attachment
of the first and second blade sections 104, 106 within the joint
sleeve 102. As indicated above, the joint ends 130, 131 of the
blade sections 104, 106 may generally be configured to be attached
within the cavity 136 defined by the joint sleeve 102 such that a
substantially continuous aerodynamic profile is defined along the
span 112 (FIG. 2) of the rotor blade assembly 100 and,
particularly, at the interfaces between the root and tip ends 138,
140 of the joint sleeve 102 and the blade shells 120 of the blade
sections 104, 106. Thus, in several embodiments, a cross-sectional
height 156 of each blade section 104, 106 may generally be reduced
at the joint ends 130, 131 to permit the joint ends 130, 131 to be
inserted within the joint sleeve 102 and to ensure that a
substantially continuous or flush surface is defined between the
blade sections 104, 106 and the joint sleeve 102.
[0037] For example, as shown in FIG. 5, in one embodiment, at least
a portion of the joint ends 130, 131 of the blade sections 104, 106
may define a tapered profile, such as by configuring the blade
shells 120 to have a tapered thickness 158, in order to permit the
joint ends 130, 131 to be positioned with the joint sleeve 102.
Additionally, the joint sleeve 102 may define a corresponding
tapered profile so that the outer surface 146 of the joint sleeve
102 is positioned substantially flush with the outer surfaces 160
of the blade shells 120. Thus, as shown, the joint sleeve 102 may
generally define tapered widths 162 at its root and tip ends 138,
140 corresponding to the tapered thicknesses 158 of the blade
shells 120. It should be appreciated that, although the tapered
widths 162 of the joint sleeve 102 are shown as defining a
substantially sharp or knife edge at the root and tip ends 138,
140, the tapered widths 162 need not define such sharp or knife
edges. For example, in one embodiment, the tapered profile of the
joint sleeve 102 may be configured to extend only partially along
the tapered profiles of the blade sections 104, 106 such that
relatively thin, blunt edges may be defined at the root and tip
ends 138, 140 of the joint sleeve 102. In such an embodiment, an
additional surface feature, such as the laminate plies described
above, may be applied at the root and tip ends 138, 140 to ensure
that a substantially continuous aerodynamic surface is defined
between the blade sections 104, 106 and the joint sleeve 102.
[0038] Alternatively, as shown in FIG. 6, the joint ends 130, 131
of the blade sections 104, 106 may define a stepped profile, such
as by configuring the blade shells 120 to have a stepped reduction
in thickness 164 at the root and tip ends 138, 140 of the joint
sleeve 102. In such an embodiment, the joint sleeve 102 may
generally define a width 166 substantially equal to the reduction
in thickness defined in the blade shells 120 so that the outer
surface 146 of the joint sleeve 102 is positioned substantially
flush with the outer surfaces 160 of the blade shells 120. In
further embodiments, it should be appreciated that the joint sleeve
102 and/or the joint ends 130, 131 of the blade sections 104, 106
may generally have any other suitable configuration that permits
the joint ends 130, 131 to be inserted within the joint sleeve
102.
[0039] In general, the tapered or stepped profiles defined at the
joint ends 130, 131 of the blade sections 104, 106 may be formed
using any suitable means. For example, in one embodiment, the
tapered or stepped profiles may be a molded feature of the blade
shells 120, such as by creating a mold having a tapered/stepped
profile defined therein or by placing a mold insert defining the
tapered/stepped profile within the mold as the blade shells 120 are
being formed. In another embodiment, the tapered or stepped profile
may be machined into the blade shells 120 after the shells 120 have
been formed, such as by using any suitable machining process and/or
any suitable machining equipment. Additionally, it should be
appreciated that the corresponding profile of the joint sleeve 102
may generally be formed using any suitable means. For example, in
one embodiment, the joint sleeve 102 may be molded or otherwise
formed to include the corresponding profile. In another embodiment,
the corresponding profile may be machined into the joint sleeve 102
using any suitable machining process and/or any suitable machining
equipment.
[0040] In a further embodiment of the present subject matter, one
of the tapered or stepped profiles of the blade shells 120 or the
corresponding profile of the joint sleeve 102 may be initially
formed and/or machined and then scanned to permit the exact
geometry of such profile(s) to be known. For example, in one
embodiment, a metrology or other 3-D scan may be performed on the
tapered profiles of the joint ends 130, 131 of each blade section
104, 106. In such an embodiment, the tapered width 162 of the joint
sleeve 102 may then be formed and/or machined based on the scan to
ensure that the tapered width 162 corresponds the tapered profiles
of the blade sections 104, 106.
[0041] Referring still to FIGS. 5 and 6, in several embodiments,
the openings 144 defined in the joint sleeve 102 may include
recessed features 170 for recessing the fasteners 142 between the
inner and outer surfaces 134, 146 of the joint sleeve 102. In
particular, the openings 144 may be configured such that the
fasteners 142 are recessed partially or fully within the joint
sleeve 102. For example, as shown in FIGS. 5 and 6, the recessed
openings 144 may be configured such that the top surface 168 of
each fastener 142 is positioned substantially flush with the outer
surface 146 of the joint sleeve 102. As such, the joint sleeve 102
may generally define a substantially continuous aerodynamic profile
between its root and tip ends 138, 140.
[0042] It should be appreciated that the size, shape and/or
configuration of the recessed features 170 of the openings 144 may
generally vary depending on the size, shape and/or configuration of
the fasteners 142 being used to attach the joint ends 130, 131 of
the blade sections 104, 106 within the joint sleeve 102. For
example, as shown in FIG. 5, the fasteners 142 may generally
comprise threaded fasteners having a fastener head 172 defining a
tapered diameter. In such an embodiment, the openings 144 formed in
the joint sleeve 102 may generally define a corresponding tapered
diameter such that the fastener head 172 may be fully recessed
within the joint sleeve 102. In another embodiment, shown in FIG.
6, the openings 144 may be configured as counterbored holes having
a shape and/or configuration corresponding to the shape and/or
configuration of the fastener head 172.
[0043] Referring still to FIGS. 5 and 6, to ensure proper
attachment of the blade sections 104, 106 within the joint sleeve
102, the disclosed rotor blade assembly 100 may also include
features for retaining the disclosed fasteners 142 within the joint
ends 130, 131 of the blade sections 104, 106. For example, in
embodiments in which the fasteners 142 are configured as a threaded
fasteners (e.g., threaded bolts), the rotor blade assembly 100 may
include a plurality of female threaded members 174 configured to
receive the threaded fasteners 142 such that a clamped interface is
provided between the inner surface 134 of the joint sleeve 102 and
the joint ends 130, 131 of the blade sections 104, 106. Thus, as
shown in FIGS. 5 and 6, a plurality of female threaded members 174
may be configured to be aligned with the openings 144 defined in
the joint sleeve 102 such that the fasteners 142 may be inserted
through the openings 144 and screwed into the threaded members 174.
For instance, in the embodiment shown in FIG. 5, the threaded
members 174 may comprise a plurality threaded channels or plugs 176
configured to be mounted or otherwise disposed within the joint
ends 130, 131 of the blade sections 104, 106. In another
embodiment, the threaded members 174 may comprise a plurality of
nuts 178 mounted directly or indirectly to an inner surface 182 of
the blade shells 120. For example, as shown in FIG. 6, the nuts 178
may be mounted onto a ganged channel or nut plate 180 extending
around the inner perimeter of each blade shell 120. It should be
appreciated that the nuts 178 may generally comprise any suitable
nut known in the art, including conventional, threaded nuts and
floating nuts. Additionally, in alternative embodiments, it should
be appreciated that the threaded members 174 may have any other
suitable configuration that permits the fasteners 142 to be
securely attached to the joint ends 130, 131 of the first and
second blade sections 104, 106.
[0044] In several embodiments of the present subject matter, the
disclosed rotor blade assembly 100 may also include a divider 184
configured to separate the joint end 130 of the first blade section
104 from the joint end 131 of the second blade section 106 within
the joint sleeve 102. The divider 131 may also serve as a stop for
locating or positioning the joint ends 130, 131 of the blade
sections 104, 106 within the joint sleeve 102. For example, in one
embodiment, the divider 184 may be positioned within the joint
sleeve 102 such that, when the joint ends 130, 131 of the blade
sections 104, 106 are inserted fully within the joint sleeve 102
and contact the divider 184, the threaded members 174 disposed
within or mounted to the blade shells 120 may generally be aligned
with the openings 144 defined in the joint sleeve 102.
[0045] It should be appreciated that the divider 184 may generally
have any suitable configuration that permits the divider 184 to
function as described herein. For instance, as shown in FIGS. 5 and
6, the divider 184 may be configured as a relatively thin member
extending around the inner perimeter of the joint sleeve 102
substantially perpendicularly to the inner surface 134.
Additionally, as shown in FIG. 5, in one embodiment, the divider
184 may extend inwardly from the inner surface 134 only partially
into the cavity 136 defined by the joint sleeve 102. Alternatively,
as shown in FIG. 6, the divider 184 may be configured to extend
from the inner surface 134 throughout the entire cavity 136 so as
to divide the cavity 136 into two separate cavities.
[0046] Referring now to FIG. 7, there is illustrated a perspective
view of a tip assembly 200 in accordance with aspects of the
present subject matter. In general, the tip assembly 200 may
include a joint sleeve 202 and a tip section 206. The joint sleeve
202 may generally be configured similarly to the joint sleeve 102
described above with reference to FIGS. 2-6. Thus, the joint sleeve
202 may define a cavity 136 (FIG. 4) extending between a tip end
240 and a root end 238 of the joint sleeve 202. The portion of the
cavity 136 defined at the tip end 240 may generally be configured
to receive a joint end 231 of the tip section 206. For example, the
joint sleeve 202 and the joint end 231 of the tip section 206 may
define corresponding tapered profiles such that the joint end 231
may be inserted into the joint sleeve 202 and attached therein
using a plurality of fasteners 242. Additionally, the joint sleeve
202 may define an aerodynamic profile generally corresponding to
the aerodynamic profile of the tip section 206. As such, when the
tip section 206 is inserted within the joint sleeve 202, the tip
assembly 200 may generally define a substantially continuous
aerodynamic profile between the joint sleeve 202 and the tip
section 206.
[0047] In general, the tip section 206 may extend from the joint
end 231 to a blade tip 210 and may have any suitable tip
configuration known in the art. For example, in one embodiment, the
tip section 206 may be configured as a straight tip section, such
as by being configured similar to the second blade section 106
described above with reference to FIGS. 2 and 3 and extending in a
substantially spanwise direction between the joint end 231 and the
blade tip 210. In another embodiment, shown in FIG. 7, the tip
section 206 may be configured as a winglet-type tip section. As
such, a winglet 290 may generally be defined between the joint end
231 and the blade tip 210. It should be appreciated that the
winglet 290 may have any suitable configuration known in the art.
For example, the winglet 290 may be configured as a suction side
winglet or as a pressure side winglet. Additionally, the winglet
290 may define any suitable sweep angle, cant angle, toe angle
and/or twist angle, all of which are commonly known terms in the
aerodynamic art. Further, the winglet 290 may define any suitable
radius of curvature and may have any suitable aspect ratio (i.e.,
ratio of the span of the winglet 290 to the planform area of the
winglet 290).
[0048] It should be appreciated that the disclosed tip assembly 200
may generally be configured as a replaceable tip for a rotor blade.
Thus, the tip assembly 200 may be configured to be attached to any
suitable inboard blade segment or section of a rotor blade. For
example, the portion of the cavity 136 (FIG. 4) defined at the root
end 238 of the joint sleeve 202 may be configured to receive an end
(not shown) of an inboard blade section (not shown), such as by
being configured to receive the joint end 130 of the first blade
section 104 described above with references to FIGS. 2-6. Thus, in
one embodiment, the end of the inboard blade section may be formed,
machined or otherwise shaped so as to define a tapered profile
corresponding to a tapered profile defined in the cavity 136 at the
root end 238 such that the blade section may be inserted into the
joint sleeve 202. Similar to the embodiments described above, the
blade section may then be attached within the joint sleeve 202
using a plurality of fasteners 242 inserted through the openings
244 defined along the root end 238.
[0049] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the 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 include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *