Note: Descriptions are shown in the official language in which they were submitted.
SNAP FIT NOSE CONE ASSEMBLY
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates generally to turbine machines, and
more
specifically to a nose cone assembly for a turbine machine.
BACKGROUND
[0002] Turbine machines provide energy for a wide range of uses. A
turbine
machine comprises at least a rotatable shaft and a plurality of blades. In
some
applications the plurality of blades comprise a fan. Examples of turbine
machines
include turbofan, turbojet, turboshaft, and turboprop engines; gas turbine
engines;
and wind turbines.
[0003] The energy produced by a turbine machine is generally either
electrical or mechanical. As one example, turbine machines are used to provide
propulsion to an aircraft. A typical turbine engine comprises a compressor, a
combustor, a high-pressure turbine, and a low-pressure turbine.
[0004] In some turbine machines, particularly in turbine engines used for
aircraft applications, it is desirable to attach a nose cone upstream from the
plurality of blades of the turbine machine. Nose cones are sometimes referred
to in
the art as "intake cones," "inlet cones," "nose cowls," or "spinners." The
nose
cone can serve to reduce drag caused by the turbine machine, improve air flow
to
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the plurality of blades, and avoid or limit damage potentially caused by
impinging
foreign objects. In supersonic aircraft, a nose cone is also advantageously
used to
slow the flow of air from supersonic flight speed to a subsonic speed before
it
enters the turbine machine.
[0005] As described below with reference to Figures lA and 1B, the
mounting of a nose cone to the turbine machine typically requires bolting the
base
of the nose cone to a support ring or retaining ring. The addition of a
support or
retaining ring and the use of a plurality of bolts to secure the nose cone
increases
the weight of the turbine machine, which is undesirable as it may negatively
impact turbine efficiency. Further, positioning, bolting, and balancing the
nose
cone is a time-- and labor-intensive process. Balancing the nose cone and
turbine
machine is necessary to address an uneven weight distribution, and typically
involves attaching balance weights to the nose cone, fan, shaft, or other part
of the
turbine machine. However, small turbofan engines typically have limited space
to
accommodate balance weights and attachment features for nose cones.
[0006] Figure 1 is a partial sectional view of a nose cone 10 connected
to a
fan rotor 12 of an inlet fan of a gas turbine engine in accordance with
conventional
methods as described in U.S. Patent Application Publication No. 2011/0236217.
The illustrated nose cone 10 comprises a flange member 14 which tapers to a
leading cone tip (not shown) and a region proximate the trailing edge 16
having a
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radial thickness greater than that of the remainder of the flange member 14. A
support ring 18 having an axially-extending flange 20 is connected to the fan
rotor
12. A bolt 22 engages the trailing edge 16 of nose cone 10 to an axial member
24
and support ring 18. One disadvantage of the configuration shown in Figure 1
and
similar nose cone mounting configurations used in the art is that the trailing
edge
16 must be reinforced by increasing the thickness of the nose cone 10, which
increases the weight of the nose cone 10 as well. Another disadvantage is the
difficulty encountered when mounting the nose cone 10 to support ring 18,
particularly when bolting the nose cone 10 to the support ring 18.
[0007]
Another nose cone configuration is illustrated in Figure 2. Figure 2is
a partial sectional view of a nose cone 10 connected to an inlet fan of a gas
turbine
engine as described in U.S. Patent No. 8,540,492. As illustrated in Figure 2,
a nose
cone 10 comprises a flange member 14 which axially extends from leading cone
tip (not shown) to a trailing edge 13. A radially thick mounting ring 26 is
formed
proximate the trailing edge 13. The mounting ring 26 defines a plurality of
apertures 15 that are spaced apart about the circumference of the mounting
ring 26.
One or more of the apertures may include a recessed portion 17 for holding one
or
more balance weights 19. A fan rotor 12 is connected to retaining ring 28
having a
mounting flange 30. A bolt 22 extends through an aperture 15 to connect nose
cone 10 to the mounting flange 30. The bolt 22 also retains balance weight 19
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within the recessed portion 17. As can be appreciated, the one or more balance
weights 19 may be added or removed from recessed portions 17 without
dismounting the nose cone 10 from the mounting flange 30.
[0008] As with Figure 1, the nose cone 10 of Figure 2 can be time- and
labor-
intensive to properly position, secure, and balance when installing. The many
bolts
22 required around the circumference of the flange member 14, as well as the
inclusion of retaining ring 28 in the assembly, can substantially increase the
weight
of the turbine machine.
[0009] It is therefore desired in the art to have improvements to nose
cones
and nose cone assemblies for turbine machines which reduce the overall weight
of
the turbine machine and simplify the process of coupling the nose cone to the
turbine machine.
SUMMARY
[0010] The present application discloses one or more of the features
recited
in the appended claims and/or the following features which, alone or in any
combination, may comprise patentable subject matter.
[0011] According to an aspect of the present disclosure, a nose cone
configured to be mounted to a hub in a turbo machine comprises a flange
extending radially around a central axis and axially from an apex portion of
the
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nose cone to a base portion of the nose cone, the flange forming an annular
hub
mating surface at the base portion and having an outer surface defining an air
flow
path; and a plurality of hub mounting elements each comprising one or more
flexible spring flanges disposed around the circumference of the base portion,
each
of the flexible spring flanges forming a hub engaging surface parallel to and
facing
in the same direction as the hub mating surface; and one or more bayonet
flanges
disposed around the circumference of the base portion, each of the bayonet
flanges
forming a hub engaging surface parallel to and facing in the opposite
direction as
the hub mating surface. In some embodiments the nose cone further comprises
one
or more pilot flanges disposed around the circumference of the base portion,
each
of the pilot flanges forming a hub engaging surface perpendicular to the hub
mating surface.
[0012] In some embodiments the nose cone comprises an annular mounting
member extending radially inward from the flange proximate the hub mating
surface, the bayonet flanges and the pilot flanges extending axially from the
mounting member. In some embodiments the flexible spring flanges extend
radially inward from the hub mating surface. In some embodiments the flexible
spring flanges comprise a feature that extends axially beyond the plane of the
hub
mating surface. In some embodiments the flexible spring flanges extend
radially
inward from the hub mating surface. In some embodiments the flexible spring
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flanges comprise a feature that extends axially beyond the plane of the hub
mating
surface. In some embodiments the flange forming an annular hub mating surface
defines a plurality of apertures each configured to receive a balancing weight
and
balancing weight fastener therein. In some embodiments each of the one or more
flexible spring flanges is removably attached to the nose cone.
100131 According to another aspect of the present disclosure, a nose cone
assembly in a turbo machine comprises a turbo machine component comprising an
annular hub extending radially around a central axis and forming a planar
mounting surface, the hub comprising one or more bayonet retainers disposed
around the circumference of the hub, the bayonet retainers extending radially
inward from the hub and forming an engagement surface parallel to and facing
the
opposite direction as the mounting surface; one or more spring flange mating
surfaces disposed around the circumference of the hub, the mating surfaces
extending radially inward from the hub and forming an engagement surface
parallel to and facing the same direction as the mounting surface; one or more
pilot
guides disposed around the circumference of the hub, the pilot guides
extending
radially inward from the hub and forming an engagement surface perpendicular
to
the mounting surface; and a nose cone mounted on the hub, the nose cone
comprising a flange extending radially around the central axis and axially
from an
apex portion of the nose cone to a base portion of the nose cone, the flange
forming
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an annular hub mating surface at the base portion and having an outer surface
defining an air flow path; and a plurality of hub mounting elements comprising
one
or more flexible spring flanges disposed around the circumference of the base
portion, each of the flexible spring flanges forming a hub engaging surface
parallel
to and facing in the same direction as the hub mating surface and being
engaged
with a respective engagement surface of a spring flange mating surface
disposed
on the hub; one or more bayonet flanges disposed around the circumference of
the
base portion, each of the bayonet flanges forming a hub engaging surface
parallel
to and facing in the opposite direction as the hub mating surface and being
engaged
with a respective engagement surface of a bayonet retainer disposed on the
hub;
and one or more pilot flanges disposed around the circumference of the base
portion, each of the pilot flanges forming a hub engaging surface
perpendicular to
the hub mating surface and being engaged with a respective engagement surface
of
a pilot guide disposed on the hub.
[0014] In some embodiments the planar mounting surface is the axially
forwardmost extension of the hub. In some embodiments the hub comprises a
plurality of blades extending radially outward from a rotor. In some
embodiments
the engagement of the hub engaging surface of the flexible spring flange with
the
spring flange mating surface of the hub results in deflection of the flexible
spring
flange. In some embodiments the deflection of the flexible spring flange
imparts
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an axially opposing force between the nose cone and the hub. In some
embodiments each of the one or more pilot guides define an aperture configured
to
receive a balancing weight. In some embodiments the nose cone assembly further
comprises a balancing weight secured to the pilot guide by a fastener. In some
embodiments the nose cone assembly further comprises an annular mounting
member extending radially inward from the nose cone flange proximate the hub
mating surface, the bayonet flanges and the pilot flanges extending axially
from the
mounting member. In some embodiments the flexible spring flanges extend
radially inward from the hub mating surface.
100151 According to another aspect of the present disclosure, a method is
disclosed of coupling a nose cone to a hub in a turbo machine having a central
axis,
the nose cone comprising a plurality of hub mounting elements disposed around
a
circumference of the nose cone base, the hub mounting elements including one
or
more flexible spring flanges, one or more bayonet flanges, and one or more
pilot
flanges; and the hub comprising a plurality of nose cone retention elements
disposed proximate a planar mounting surface, the plurality of nose cone
retention
elements comprising one or more spring flange mating surfaces, one or more
bayonet retainers, and one or more pilot guides; wherein the method comprises
positioning the nose cone axially forward of and concentric with the hub;
moving
the nose cone in an axially aft direction until at least a portion of the one
or more
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bayonet flanges is disposed axially aft of a respective one or more bayonet
retainers; and rotating the nose cone to engage the one or more flexible
spring
flange and a respective spring flange mating surface and to engage the one or
more
bayonet flange and a respective bayonet retainer.
100161 In some embodiments the step of rotating the nose cone further
engages the one or more pilot flanges and a respective pilot guide. In some
embodiments the engagement of the one or more flexible spring flange with a
respective spring flange mating surface results in deflection of the flexible
spring
flange, and wherein the deflection imparts an axially opposing force between
the
nose cone and the hub.
100171 According to another aspect of the present disclosure, a nose cone
configured to be mounted to a hub in a turbo machine comprises a flange
extending radially around a central axis and axially from an apex portion of
the
nose cone to a base portion of the nose cone, the flange forming an annular
hub
mating surface at the base portion and having an outer surface defining an air
flow
path; and a plurality of hub mounting elements comprising: one or more bayonet
flanges disposed around the circumference of the base portion, each of the
bayonet
flanges forming a hub engaging surface parallel to and facing in the opposite
direction as the hub mating surface; and two or more apertures defined by the
flange forming the annular hub mating surface, each of the apertures
configured to
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receive an fastener therethrough. In some embodiments the nose cone further
comprises one or more pilot flanges disposed around the circumference of the
base
portion, each of the pilot flanges forming a hub engaging surface
perpendicular to
the hub mating surface.
100181 In some embodiments the nose cone comprises an annular mounting
member extending radially inward from the flange proximate the hub mating
surface, the bayonet flanges and the pilot flanges extending axially from the
mounting member. In some embodiments each of the two or more apertures
include a countersink configured to receive a balance weight. In some
embodiments each of the two or more apertures pass through the annular
mounting
member. In some embodiments each hub engaging surface of the one or more
bayonet flanges comprises a radially tapered surface. In some embodiments the
radially tapered surface comprises a parabolic taper.
100191 In some embodiments the flange forming an annular hub mating
surface defines a plurality of apertures each configured to receive a
balancing
weight and balancing weight fastener therein. In some embodiments the flange
extending radially around the central axis forms a parabolic outer surface of
the
nose cone. In some embodiments the flange extending radially around the
central
axis forms a frustoconical outer surface of the nose cone.
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100201 According to another aspect of the present disclosure, a nose cone
assembly in a turbo machine comprises a turbo machine component comprising an
annular hub extending radially around a central axis and forming a planar
mounting surface, the hub comprising: one or more bayonet retainers disposed
around the circumference of the hub, the bayonet retainers extending radially
inward from the hub and forming an engagement surface parallel to and facing
the
opposite direction as the mounting surface; two or more mounting flanges
disposed around the circumference of the hub, each of the mounting flanges
extending axially forward from the planar mounting surface and defining an
aperture configured to receive a fastener; and one or more pilot guides
disposed
around the circumference of the hub, the pilot guides extending radially
inward
from the hub and forming an engagement surface perpendicular to the mounting
surface; and a nose cone mounted on the hub, the nose cone comprising a flange
extending radially around the central axis and axially from an apex portion of
the
nose cone to a base portion of the nose cone, the flange forming an annular
hub
mating surface at the base portion and having an outer surface defining an air
flow
path; and a plurality of hub mounting elements comprising: one or more bayonet
flanges disposed around the circumference of the base portion, each of the
bayonet
flanges forming a hub engaging surface parallel to and facing in the opposite
direction as the hub mating surface and being engaged with a respective
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engagement surface of a bayonet retainer disposed on the hub; two or more
apertures defined by the flange forming the annular hub mating surface, each
of the
apertures configured to receive a fastener therethrough and being engaged with
the
aperture of a respective one of the mounting flanges by the fastener; and one
or
more pilot flanges disposed around the circumference of the base portion, each
of
the pilot flanges forming a hub engaging surface perpendicular to the hub
mating
surface and being engaged with a respective engagement surface of a pilot
guide
disposed on the hub.
100211 In some embodiments the nose cone assembly further comprises two
or more fasteners, each fastener secured through a respective one of the one
or
more apertures defined by the flange forming the annular hub mating surface
and
of the one or more apertures defined by the mounting flange. In some
embodiments the one or more apertures defined by the flange forming the
annular
hub mating surface each include a countersink configured to receive a balance
weight. In some embodiments each of the one or more pilot guides define an
aperture configured to receive a balancing weight. In some embodiments the
nose
cone assembly further comprises a balancing weight secured to the pilot guide
by a
fastener. In some embodiments the nose cone assembly further comprises an
annular mounting member extending radially inward from the nose cone flange
proximate the hub mating surface, the bayonet flanges and the pilot flanges
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extending axially from the mounting member. In some embodiments the hub
comprises a plurality of blades extending radially outward from a rotor.
[0022] According to another aspect of the present disclosure, a method of
coupling a nose cone to a hub in a turbo machine having a central axis, the
nose
cone comprising a plurality of hub mounting elements disposed around a
circumference of the nose cone base, the hub mounting elements including one
or
more bayonet flanges and one or more pilot flanges, the nose cone defining two
or
more nose cone apertures proximate the nose cone base; and the hub comprising
a
plurality of nose cone retention elements disposed proximate a planar mounting
surface, the plurality of nose cone retention elements comprising one or more
bayonet retainers, one or more pilot guides, and two or more mounting flanges
each defining a respective mounting flange aperture; wherein the method
comprises: positioning the nose cone axially forward of and concentric with
the
hub; moving the nose cone in an axially aft direction until at least a portion
of the
one or more bayonet flanges is disposed axially aft of a respective one or
more
bayonet retainers; and rotating the nose cone to engage the one or more
bayonet
flange and a respective bayonet retainer and to align each of the two or more
apertures defined by the nose cone with a respective one of the two or more
apertures defined by the mounting flange.
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[0023] In some embodiments the method further comprises securing the nose
cone to the hub by securing a fastener through one of the nose cone apertures
and a
corresponding one of the mounting flange apertures. In some embodiments the
step of rotating the nose cone further engages the one or more pilot flanges
and a
respective pilot guide.
[0024] According to another aspect of the present disclosure, a nose cone
configured to be mounted to a hub in a turbo machine comprises: a flange
extending radially around a central axis and axially from an apex portion of
the
nose cone to a base portion of the nose cone, the flange forming an annular
hub
mating surface at the base portion and having an outer surface defining an air
flow
path; and a plurality of hub mounting elements disposed around the
circumference
of the base portion, each of the hub mounting elements comprising a flexible
flange extending toward the central axis and having a ridge protruding from a
radially outward facing surface; wherein the flexible flange is configured to
deflect
toward the central axis upon engagement with the hub.
[0025] In some embodiments the flexible flange extends axially beyond the
hub mating surface. In some embodiments the nose cone comprises an annular
mounting member extending radially inward from the flange proximate the hub
mating surface, the flexible flanges extending axially from the mounting
member.
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In some embodiments the flexible flange extends axially beyond the hub mating
surface.
[0026] In some embodiments the flange extending radially around the
central
axis forms a parabolic outer surface of the nose cone. In some embodiments the
flange extending radially around the central axis forms a frustoconical outer
surface of the nose cone. In some embodiments the nose cone further comprises
two or more apertures defined by the flange forming the annular hub mating
surface, each of the apertures configured to receive an fastener therethrough.
In
some embodiments each of the two or more apertures include a countersink
configured to receive a balance weight. In some embodiments a leading edge of
the flexible flange is chamfered. In some embodiments the nose cone further
comprises a circumferential alignment flange extending axially from the flange
forming the annular hub mating surface. In some embodiments the nose cone
further comprises a circumferential alignment flange extending axially from
the
mounting member.
[0027] According to another aspect of the present disclosure, a nose cone
assembly in a turbo machine comprises a turbo machine component comprising an
annular hub extending radially around a central axis and forming a planar
mounting surface, the hub comprising one or more mounting portions disposed
around the circumference of the hub, the mounting portions extending radially
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inward from the hub and forming a mounting surface which defines a groove and
a
nose cone mounted on the hub, the nose cone comprising a flange extending
radially around the central axis and axially from an apex portion of the nose
cone
to a base portion of the nose cone, the flange forming an annular hub mating
surface at the base portion and having an outer surface defining an air flow
path;
and a plurality of hub mounting elements disposed around the circumference of
the
base portion, each of the hub mounting elements comprising a flexible flange
extending toward the central axis and having a ridge protruding from a
radially
outward facing surface, wherein the flexible flange is configured to deflect
toward
the central axis upon engagement with the hub, and wherein each ridge is
engaged
with a groove of a respective one of the one or more mounting portions.
[0028] In some embodiments the nose cone assembly further comprises two
or more mounting flanges disposed around the circumference of the hub, each of
the mounting flanges extending axially forward from the planar mounting
surface
and defining an aperture configured to receive a fastener; and two or more
apertures defined by the flange forming the annular hub mating surface, each
of the
apertures configured to receive a fastener therethrough and being engaged with
the
aperture of a respective one of the mounting flanges by the fastener.
[0029] In some embodiments the one or more apertures defined by the
flange
forming the annular hub mating surface each include a countersink configured
to
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receive a balance weight. In some embodiments the mounting surface further
defines a guide channel proximate the groove. In some embodiments the nose
cone further comprises an alignment flange abutting an alignment tab of the
hub.
In some embodiments an engaged position of the flexible flange is inwardly
deflected relative to an unengaged position. In some embodiments the hub
comprises a plurality of blades extending radially outward from a rotor.
100301 According to yet another aspect of the present disclosure, a
method is
disclosed of coupling a nose cone to a hub in a turbo machine having a central
axis,
the nose cone comprising a plurality of hub mounting elements disposed around
the circumference of a base portion of the nose cone, each of the hub mounting
,
elements comprising a flexible flange extending toward the central axis and
having
a ridge protruding from a radially outward facing surface, the hub comprising
one
or more mounting portions disposed around the circumference of the hub, the
mounting portions extending radially inward from the hub and forming a
mounting
surface which defines a groove; the method comprising positioning the nose
cone
axially forward of and concentric with the hub, with each ridge of the
plurality of
hub mounting elements axially aligned with a respective groove of the
plurality of
mounting portions; and moving the nose cone in an axially aft direction until
the
flexible flanges deflect in an inward direction and each ridge of the
plurality of hub
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mounting elements is engaged in a respective groove of the plurality of
mounting
portions.
[0031] In some embodiments an engaged position of the flexible flange is
inwardly deflected relative to an unengaged position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The following will be apparent from elements of the figures, which
are provided for illustrative purposes and are not necessarily to scale.
[0033] Figure 1 is a partial sectional view of a nose cone connected to a
fan
rotor of an inlet fan of a gas turbine engine.
[0034] Figure 2 is a partial sectional view of a nose cone connected to a
fan
rotor of an inlet fan of a gas turbine engine.
[0035] Figure 3A is an isometric view of a nose cone in accordance with
some embodiments of the present disclosure.
[0036] Figure 3B is a sectional view of a nose cone in accordance with
some
embodiments of the present disclosure.
[0037] Figure 4 is an isometric view of a hub configured to be coupled to
the
nose cone illustrated in Figures 3A and 3B, in accordance with some
embodiments
of the present disclosure.
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[0038] Figure 5A is a partial sectional view of the nose cone of Figures
3A
and 3B coupled to the hub of Figure 4, shown along axis A, in accordance with
some embodiments of the present disclosure.
[0039] Figure 5B is a partial sectional view of the nose cone of Figures
3A
and 3B coupled to the hub of Figure 4, shown along axis B, in accordance with
some embodiments of the present disclosure.
[0040] Figure 5C is a partial sectional view of the nose cone of Figures
3A
and 3B coupled to the hub of Figure 4, shown along axis C, in accordance with
some embodiments of the present disclosure.
[0041] Figure 5D is a partial sectional view of the nose cone of Figures
3A
and 3B coupled to the hub of Figure 4, shown along axis B, in accordance with
some embodiments of the present disclosure.
[0042] Figure 6 is a partial isometric view of the base of a nose cone
having a
pocket configured to receive a removable spring mechanism in accordance with
some embodiments of the present disclosure.
[0043] Figure 7 is a removable spring mechanism in accordance with some
embodiments of the present disclosure.
[0044] Figure 8 is an isometric view of a nose cone in accordance with
some
embodiments of the present disclosure.
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[0045] Figure 9 is an isometric view of a hub configured to be coupled to
the
nose cone illustrated in Figure 8, in accordance with some embodiments of the
present disclosure.
[0046] Figure 10A is a partial sectional view of the nose cone of Figure
8
coupled to the hub of Figure 9, shown along axis A, in accordance with some
embodiments of the present disclosure.
[0047] Figure 10B is a partial sectional view of the nose cone of Figure
8
coupled to the hub of Figure 9, shown along axis B, in accordance with some
embodiments of the present disclosure.
[0048] Figure 10C is a partial sectional view of the nose cone of Figure
8
coupled to the hub of Figure 9, shown along axis C, in accordance with some
embodiments of the present disclosure.
[0049] Figure 10D is a partial sectional view of the nose cone of Figure
8
coupled to the hub of Figure 9, shown along axis D, in accordance with some
embodiments of the present disclosure.
[0050] Figure 11 is an isometric view of a bayonet flange of a nose cone
in
accordance with some embodiments of the present disclosure.
[0051] Figure 12 is an isometric view of a nose cone in accordance with
some embodiments of the present disclosure.
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[0052] Figure 13 is an isometric view of a hub configured to be coupled
to
the nose cone illustrated in Figure 12, in accordance with some embodiments of
the present disclosure.
[0053] Figure 14A is a partial sectional view of the nose cone of Figure
12
coupled to the hub of Figure 13, shown along a plane intersecting one of the
one or
more hub mounting members, in accordance with some embodiments of the
present disclosure.
[0054] Figure 14B is a partial sectional view of the nose cone of Figure
12
coupled to the hub of Figure 13, shown along plane which does not intersect a
hub
mounting member but which does intersect an aperture, in accordance with some
embodiments of the present disclosure.
[0055] Figure 15 is a partial profile view of the inner surface of a
rotor
having a plurality of discreet mounting portions in accordance with some
embodiments of the present disclosure.
[0056] Figure 16 is a partial sectional view of the nose cone of Figure
12
coupled to the hub of Figure 13 in accordance with some embodiments of the
present disclosure.
[0057] While the present disclosure is susceptible to various
modifications
and alternative forms, specific embodiments have been shown by way of example
in the drawings and will be described in detail herein. It should be
understood,
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however, that the present disclosure is not intended to be limited to the
particular
forms disclosed. Rather, the present disclosure is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope of the
disclosure as
defined by the appended claims.
DETAILED DESCRIPTION
[0058] For the purposes of promoting an understanding of the principles
of
the disclosure, reference will now be made to a number of illustrative
embodiments
illustrated in the drawings and specific language will be used to describe the
same.
[0059] As used herein, a turbine machine is understood to reference any
machine using a turbine including gas turbine engines, wind turbines, steam
turbines, water turbines, and the like. A turbine machine comprises at least a
rotatable shaft and a plurality of blades.
[0060] The nose cone herein disclosed may be appropriately coupled to a
rotating or a non-rotating component. Although the embodiments herein disclose
the nose cone coupled to a bladed rotor which is rotatable, one of skill in
the art
would recognize that the disclosed nose cone is equally suitable for coupling
to a
non-rotating component. One of skill in the art would additionally recognize
that
the disclosed nose cones 110 and nose cone assemblies 100 could be used on a
wide range of machines, including aircraft engines, non-rotating aircraft
components, missiles, and UAVs.
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[0061] The present disclosure is directed to a nose cone and nose cone
assembly for reducing the weight and complexity required to mount the nose
cone
to a turbine machine. Although the disclosed nose cone is advantageously used
with any number of turbine machines, the embodiments below may describe the
nose cone as used with a turbine engine, such as a gas turbine engine for
aviation
applications. However, one of skill in the art would understand that the
disclosed
apparatus, systems, and methods are not so limited.
[0062] This disclosure presents embodiments to overcome the
aforementioned deficiencies of nose cones and nose cone mounting
configurations.
More specifically, this disclosure is directed to a nose cone, nose cone
assembly,
and shaft balancing assembly which reduce the weight and complexity of
mounting
or coupling the nose cone. Detailed descriptions of the disclosed nose cone,
nose
cone assembly, and shaft balancing assembly, and additional advantages
thereof,
are presented below.
[0063] Figure 3A is an isometric view of a nose cone 110 and Figure 3B is
a
sectional view of the nose cone 110 in accordance with some embodiments of the
present disclosure. Nose cone 110 comprises a flange member 114 which
terminates at an annular hub mating surface 118 at the base portion 119 of
nose
cone 110. Flange member 114 has an outer surface 112 which defines an air flow
path around the nose cone 110. Flange member 114 may comprise an annular
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mounting member 113 which extends radially inward from flange member 114
proximate the hub mating surface 118. Flange member 114 further extends
radially about a central axis to form a hollow cone structure. In some
embodiments flange member 114 may form a frustoconical outer surface 112,
while in other embodiments flange member may form a parabolic outer surface
112. Flange member 114 may be referred to as the nose cone body.
100641 Flange member 114 extends axially from an apex portion 111 to base
portion 119. In some embodiments flange member 114 extends forward to
integrally form a leading tip 116 of the nose cone 110. In other embodiments,
such
as the embodiment shown in Figures 3A and 3B the flange member 114 terminates
at apex portion 111 with a radially inward extending member 115 and a nose
cone
tip 117 is removably mounted to the member 115. Thus in some embodiments the
flange member 114 extends from a leading tip 116 of the nose cone 110 to a hub
mating surface 118, whereas in other embodiments the flange member 114 extends
from a radially inward extending member 115 to a hub mating surface 118. Nose
cone 110 may be formed of metallic or composite materials.
100651 In some embodiments mounting member 113 may be
circumferentially segmented such that the full radial thickness of the member
113
is not present at all positions around the circumference of the flange member
114.
In other words, in some embodiments the radially inward facing surface 125 of
the
24
CA 2976726 2017-08-17
mounting member 113 has a constant diameter around the circumference, while in
other embodiments the radially inward facing surface 125 has varying
diameters.
Reductions in the radial thickness of the mounting member 113 may be made as a
weight saving alteration.
[0066] Mounting member 113 and/or hub mating surface 118 may have a
plurality of hub mounting elements 130 disposed circumferentially about the
mounting member 113 and/or hub mating surface 118. Hub mounting elements
130 are configured to engage a hub 120. Hub mounting elements 130 include, but
are not limited to, a flexible spring flange 131, a bayonet flange 132, and a
pilot
flange 133. Hub mounting elements 130 are spaced about the circumference of
the
mounting member 113 and/or hub mating surface 118 as indicated by the axes
labeled A, B, and C. In some embodiments flexible spring flange 131 extends
radially inward from the hub mating surface 118 while bayonet flange 132 and
pilot flange 133 extend axially aft from mounting member 113.
[0067] Sectional views of the nose cone 110 coupled to the hub 120 as
intersected by a plane along the axes A, B, and C are presented in Figures 5A,
5B,
and 5C. The coupling of nose cone 110 to hub 120 forms a nose cone assembly
100.
[0068] In some embodiments the positioning of the hub mounting elements
130 is symmetrical, such that an element 130 at one intersection of axis A and
the
CA 2976726 2017-08-17
hub mating surface 118 is the same as an element 130 at the opposite
intersection
of axis A and the hub mating surface 118. However, in some embodiments the hub
mounting elements 130 are not symmetrically positioned, such that the opposite
intersection of axis A and the hub mating surface 118 may have a different
mounting element 130 or no mounting element 130.
100691 At a first circumferential position identified by the intersection
of axis
A and the hub mating surface 118, a flexible spring flange 131 is coupled to
the
hub mating surface 118. Spring flange 131 comprises a radially inward
extending
member 135 which may have a varying axial thickness. In the illustrated
embodiment, for example, the member 135 is relatively thicker in the axial
dimension at the radially inward end. Member 135 has a hub engaging surface
138
which may be parallel to and facing the same direction as hub mating surface
118.
In some embodiments spring flange 131 comprises a member 135 which extends
radially inward from and axially beyond the plane of the hub mating surface
118.
100701 Spring flange 131 is configured to provide a biasing force in the
axial
direction. When nose cone 110 is coupled to hub 120, spring flange 131
provides
an axial separation force between the nose cone 110 and hub 120. In some
embodiments spring flange 131 may include lead-in features such as chamfers to
aid the coupling of nose cone 110 to hub 120.
26
CA 2976726 2017-08-17
[0071] During the coupling process of the nose cone 110 to the hub 120,
the
spring flange 131 is configured to deflect as the peak assembly displacement
is
greater than the axial displacement provided by the spring flange 131 once
fully
assembled. In some embodiments the thickness of spring flange 131 is adapted
to
provide a desired axial displacement force. In some embodiments the spring
flange 131 may include a protruding and/or mating receptacle feature
configured to
engage once the nose cone 110 and hub 120 are correctly circumferentially
positioned during assembly. Such a feature aids in maintaining circumferential
alignment between the nose cone 110 and hub 120 during operation.
100721 The axial displacement force imparted by the one or more spring
flanges 131 disposed about the base portion 119 of nose cone 110 must be
sufficient to withstand maximum operating loads. As with most nose cone
designs, this includes the maximum loading experienced during a bird strike.
The
spring flanges 131 may be configured to impart sufficient axial displacement
force
such that decoupling of the nose cone 110 and hub 120 is only possible under
loading from an assembly/disassembly tool. Such a tool may engage the nose
cone
110 via trim balance apertures in surface 112.
100731 At a second circumferential position identified by the
intersection of
axis B and the hub mating surface 118, a bayonet flange 132 extends from the
mounting member 113. Bayonet flange 132 comprises an axially extending
27
CA 2976726 2017-08-17
member 136 and a retaining lip 137. Retaining lip 137 has a hub engaging
surface
139 which may be parallel to and facing in the opposite direction as the hub
mating
surface 118. Bayonet flange 132 is configured to engage a portion of hub 120
resulting in the axial retention of nose cone 110. In some embodiments bayonet
flange 132 may include lead-in features such as chamfers to aid the coupling
of
nose cone 110 to hub 120.
[0074] At a third circumferential position identified by the intersection
of
axis C and the hub mating surface 118, a pilot flange 133 extends from the
mounting member 113. As illustrated, pilot flange 133 extends axially aft from
the
mounting member 113 and is configured to engage a portion of hub 120 to
maintain concentricity of nose cone 110 to hub 120. Pilot flange 133 has a hub
engaging surface 134 which may be perpendicular to the hub mating surface 118.
[0075] One or more flexible spring flanges 131 may be disposed about the
circumference of base portion 119. One or more bayonet flanges 132 may be
disposed about the circumference of base portion 119. One or more pilot
flanges
133 may be disposed about the circumference of base portion 119.
[0076] Figure 4 is an isometric view of a hub 120 configured to be
coupled to
the nose cone 110 illustrated in Figures 3A and 3B, in accordance with some
embodiments of the present disclosure. In the illustrated embodiment, hub 120
is a
bladed rotor of a turbine machine. However, in other embodiments the hub 120
28
CA 2976726 2017-08-17
may be another component of a turbine machine including a static (i.e. non-
rotating) component.
[0077] In the illustrated embodiment, hub 120 comprises a hollow
cylindrical
rotor 122 which extends radially about a central axis and has a plurality of
blades
123 extending radially therefrom. An axially aft portion of the rotor 122 may
comprise a mating flange 124 configured to couple the rotor 122 to a rotating
shaft
(not shown). An axially forward portion of the rotor 122 may comprise a
plurality
of nose cone retention elements 140 configured to retain the nose cone 110
described with reference to Figures 3A and 3B. Nose cone retention elements
140
may include one or more spring flange mating surfaces 141, bayonet retainers
142,
and pilot guides 143. Nose cone retention elements 140 may be
circumferentially
disposed about the forward portion of the rotor 121 and may be spaced apart by
gaps 144. The forward portion of the rotor 121 may comprise a planar mounting
surface 145.
[0078] Spring flange mating surfaces 141 are configured to abut spring
flanges 131 when nose cone 110 is coupled to hub 120. Each spring flange 131
is
aligned with a respective spring flange mating surface 141 and pushes against
the
spring flange mating surface 141 to impart axial force on nose cone 110.
[0079] Bayonet retainers 142 are configured to retain bayonet flanges 132
of
nose cone 110 when nose cone 110 is coupled to hub 120. Each bayonet flange
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CA 2976726 2017-08-17
132 is aligned with a respective bayonet retainer 142. Bayonet retainers 142
extend radially inward from rotor 121 such that the retention lip 137 of a
bayonet
flange 132 will engage the bayonet retainer 142 and axially forward motion of
the
nose cone 110 will be prevented.
[0080] Pilot guides 143 are configured to abut pilot flanges 133 in order
to
maintain concentricity of nose cone 110 to hub 120. In some embodiments pilot
guides 143 comprise a radially extending portion 146 and an axially extending
portion 147. The axially extending portion 147 is configured to engage the
pilot
flange 133 when nose cone 110 is coupled to hub 120. Each pilot flange 133 is
aligned with a respective pilot guide 143. The radially extending portion 146
may
include an aperture 148 configured to receive balancing weights 149.
[0081] In some embodiments an axially forward facing planar mounting
surface 145 represents the forwardmost extension of the rotor 121. In some
embodiments one or more of the nose cone retention elements 140 are integral
to
mounting surface 145.
[0082] The nose cone 110 described above with reference to Figures 3A and
3B may be coupled to the hub 120 described above with reference to Figure 4.
To
couple the nose cone 110 and hub 120, the nose cone 110 must be positioned
axially forward from the hub 120 with bayonet flanges 132 circumferentially
aligned with gaps 144 between the nose cone retention elements 140 of hub 120.
CA 2976726 2017-08-17
Nose cone 110 may then be moved axially aft such that the retention lip 137 of
each bayonet flange 132 is axially aft of the bayonet retainers 142 of the hub
120.
Nose cone 110 may then be rotated to engage each bayonet flange 132 with a
respective bayonet retainer 142. In some embodiments, it will be essential
that the
retention lips 137 of the bayonet flanges 132 begin to engage their respective
bayonet retainer 142 prior to engagement of the spring flanges 131. This will
allow the retention lips 137 to be axially engaged with hub 120 prior to the
axial
separating force being imparted by the spring flanges 131, and thus prevent
separation of nose cone 110 from hub 120.
[0083] Figures 5A, 5B, 5C, and 5D provide sectional views of a nose cone
110 coupled to a hub 120.
[0084] Figure 5A is a partial sectional view of the nose cone 110 of
Figures
3A and 3B coupled to the hub 120 of Figure 4, shown along axis A, in
accordance
with some embodiments of the present disclosure. When coupled, spring flange
131 abuts an opposing spring flange mating surface 141. When abutting the
spring
flange mating surface 141, spring flange 131 is flexed thus imparting an
axially
forwarded force on nose cone 110. Each spring flange 131 is aligned with a
respective spring flange mating surface 141 and pushes against the spring
flange
mating surface 141 to impart axial force on nose cone 110.
31
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[0085] Figure 5B is a partial sectional view of the nose cone 110 of
Figures
3A and 3B coupled to the hub 120 of Figure 4, shown along axis B, in
accordance
with some embodiments of the present disclosure. Retention lip 137 of bayonet
flange 132 is engaged axially aft of bayonet retainer 142, thus preventing
axially
forward movement of nose cone 110. In some embodiments hub mating surface
118 may abut rotor 121.
[0086] Figure 5C is a partial sectional view of the nose cone 110 of
Figures
3A and 3B coupled to the hub 120 of Figure 4, shown along axis C, in
accordance
with some embodiments of the present disclosure. Pilot flange 133 abuts the
axially extending portion 147 of pilot guide 143 to ensure the proper
disposition of
nose cone 110 relative to hub 120. In rotating embodiments, the abutment of
pilot
guide 143 and pilot flange 133 ensures proper concentricity of nose cone 110
to
hub 120.
[0087] In some embodiments an aperture 148 may be defined by radially
extending portion 146 of the pilot guide 143 and may be configured to receive
one
or more balancing weights 149 which may be coupled to pilot guide 143 with a
fastener. During nose cone 110 balancing, balancing weights 149 of varying
masses may be placed in aperture 148 to ensure an evenly distributed nose cone
mass, which assists with stable rotation of the nose cone 110 during
operation. In
32
CA 2976726 2017-08-17
some embodiments a plurality of apertures 148 are provided, each defined by a
respective pilot guide 143.
100881 Figure 5D is a partial sectional view of the nose cone 110 of
Figures
3A and 3B coupled to the hub 120 of Figure 4, shown along axis B, in
accordance
with some embodiments of the present disclosure. Retention lip 137 of bayonet
flange 132 is engaged axially aft of bayonet retainer 142, thus preventing
axially
forward movement of nose cone 110. In some embodiments hub mating surface
118 may abut rotor 121.
[0089] In the embodiment illustrated in Figure 5D, an aperture 160 is
provided through mounting member 113 for the placement of balancing weights
162. A bolt 161 and retaining nut 163 may be used to secure the balancing
weight
162 in position. During nose cone 110 balancing, balancing weights 162 of
varying masses may be placed in aperture 160 to ensure an evenly distributed
nose
cone mass, which assists with stable rotation of the nose cone 110 during
operation. In some embodiments a plurality of apertures 160 are provided in
nose
cone 110. In some embodiments nose cone 110 further defines a countersink 164
around the aperture 160 configured to receive the balancing weight 162.
100901 In some embodiments balancing weight 162 is omitted, and balancing
of the nose cone 110 is achieved using fasteners of varying lengths and thus
of
varying weights. This balancing method allows for reduction of the diameter of
33
CA 2976726 2017-08-17
the countersink 164, and thus the reduction of the reinforcement required in
the
vicinity of countersink 164. Reducing the thickness of flange member 114
and/or
mounting member 113 reduces the weight of nose cone 110.
[0091] In some embodiments, the manufacture of nose cone 110 is
simplified
by omitting the spring flanges 131 during initial manufacture. Spring flanges
131
are then added to nose cone 110 prior to coupling with hub 120. Figure 6 is a
partial isometric view of the base portion 119 of a nose cone 110 having a
pocket
601 configured to receive a removable spring mechanism 701 in accordance with
some embodiments of the present disclosure. The pocket 601 is formed in the
surface 112 of flange 114, and in some embodiments defines an aperture 603.
Figure 7 is a removable spring mechanism 701 configured to be inserted into
the
pocket 601 in accordance with some embodiments of the present disclosure. In
some embodiments, spring mechanism 701 may be configured to partially rest in
pocket 601 and be secured with a fastener through a spring mechanism hole 703
and the aperture 603. In other embodiments, spring mechanism 701 may be
configured to be inserted at least partially through the aperture 603 and may
be
secured in place with or without a fastener. In some embodiments spring
mechanism 701 may be secured through the aperture 603 with an adhesive.
[0092] In some embodiments of the present disclosure, a nose cone
assembly
100 is provided which significantly reduces the number of fasteners required
to
34
CA 2976726 2017-08-17
couple nose cone 110 to hub 120. For example, Figure 8 is an isometric view of
a
nose cone 110 in accordance with some embodiments of the present disclosure.
In
the embodiment illustrated in Figure 8, nose cone 110 has a plurality of hub
mounting elements 130 including a plurality of bayonet flanges 132 and, in
some
embodiments, a plurality of pilot flanges 133. Hub mounting elements 130 are
configured to engage hub 120 and to retain coupling of nose cone 110 to hub
120.
Hub mounting elements 130 are spaced about the circumference of the mounting
member 113 or hub mating surface 118 as indicated by axes A and B. Sectional
views of the nose cone 110 coupled to hub 120 as intersected by a plane along
axes
A, B, and C are presented in Figures 10A, 10B, and 10C.
100931 The nose cone 110 of Figure 8 additionally has at least a pair of
apertures 801 which pass through the flange member 114 and mounting member
113. Apertures 801 are configured to receive a fastener there through for
coupling
the nose cone 110 to a hub 120. Apertures 801 are located along an axial plane
extending from axis A. Additionally a plurality of bayonet flanges 132 are
spaced
about the circumference of the mounting member 113, and at least one bayonet
flange 132 is disposed in an axial plane extending from axis B.
100941 Figure 9 is an isometric view of a hub 120 configured to be
coupled to
the nose cone 110 illustrated in Figure 8, in accordance with some embodiments
of
the present disclosure. Hub 120 is illustrated in Figure 9 as a bladed rotor;
CA 2976726 2017-08-17
however, the hub 120 may take the form of other engine components including
non-rotating components.
100951 Hub 120 comprises a rotor 121 with a plurality of blades 123
extending radially outward therefrom. The axially forward portion of the rotor
121
comprises a plurality of nose cone retention elements 140 configured to engage
the
hub mounting elements 130 of the nose cone 110 and therefore retain coupling
between the nose cone 110 and hub 120. Nose cone retention elements 140 in the
illustrated embodiment include one or more of a mounting flange 901, a bayonet
retainer 142, and pilot guides 143. Nose cone retention elements 140 may be
circumferentially disposed about the forward portion of rotor 121 and may be
spaced apart by gaps.
100961 Each mounting flange 901 extends axially forward from the axially
forward portion of the rotor 121 and defines a mounting aperture 903. The
mounting flange 901 may be sized and configured such that the mounting
aperture
903 aligns with one of the apertures 801 of the nose cone 110 when nose cone
110
is properly coupled to hub 120. A fastener such as a bolt or screw is able to
be
passed through aperture 801 and mounting aperture 903 in order to secure nose
cone 110 to hub 120. Mounting flanges 901 thus serve primarily to prevent
either
axial or circumferential motion of nose cone 110 relative to hub 120. By
preventing circumferential motion of nose cone 110 relative to hub 120,
mounting
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CA 2976726 2017-08-17
flanges 901 ensure continuous engagement of bayonet flanges 132 to bayonet
retainers 142.
100971 In the illustrated embodiment a pair of mounting flanges 901 are
provided with hub 120 and configured to align with a pair of apertures 801. In
some embodiments only a single mounting flange 901 and aperture 801 are
provided. In other embodiments, more than two mounting flanges 901 and
apertures 801 are provided.
100981 As described above, bayonet retainers 142 and pilot guides 143 are
configured to engage bayonet flanges 132 and pilot flanges 133, respectively.
Bayonet flanges 132 and bayonet retainers 142 are configured to reduce the
load
capability requirements on the mounting flanges 901 described above.
[0099] The nose cone 110 described above with reference to Figure 8 may
be
coupled to the hub 120 described above with reference to Figure 9. To couple
the
nose cone 110 and hub 120, the nose cone 110 must be positioned axially
forward
from the hub 120 with bayonet flanges 132 circumferentially aligned with gaps
144 between the nose cone retention elements 140 of hub 120. Nose cone 110 may
then be moved axially aft such that the retention lip 137 of each bayonet
flange 132
is axially aft of the bayonet retainers 142 of the hub 120. Nose cone 110 may
then
be rotated to engage each bayonet flange 132 with a respective bayonet
retainer
142. Rotating the nose cone 110 into proper alignment with hub 120 will serve
to
37
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(1) engage the bayonet flanges 132 to the bayonet retainers 142, (2) align
apertures
801 with a respective aperture 903, and (3) engage pilot flanges 133 to the
axially
extending portion 147 of pilot guide 143. A fastener is then passed through
the
aperture 801 and aperture 903 and secured to complete the coupling of nose
cone
110 to hub 120.
101001 The use of a plurality of bayonet flanges 132 and bayonet
retainers
142 when coupling nose cone 110 to hub 120 advantageously allows for reduction
of fasteners as compared to the prior art. Reducing the number of bolts which
pass
through the nose cone 110 allows for reduction in the overall weight of the
nose
cone assembly, both by reducing the heavy bolts used to couple nose cone 110
to
hub 120 and by reducing the amount of reinforcement required around the
receiving apertures in the nose cone 110. Further, ease of manufacture is
improved
by reducing the number of receiving apertures which are required to pass
through
the base of the nose cone 110. The ease of assembly may also be improved as
less
fasteners are required to secure nose cone 110 to hub 120.
[0101] Figures 10A, 10B, 10C, and 10D provide sectional views of a nose
cone 110 coupled to a hub 120. Figure 10A is a partial sectional view of the
coupling of the nose cone of Figure 8 and the hub 120 of Figure 9, shown along
axis A, in accordance with some embodiments of the present disclosure.
38
CA 2976726 2017-08-17
[0102] In some embodiments a balancing weight 162 may be included when
securing nose cone 110 to hub 120 with a bolt 161. A bolt 161 and retaining
nut
163 may be used to secure the balancing weight 162 in position. During nose
cone
110 balancing, balancing weights 162 of varying masses may be placed in
aperture
160 to ensure an evenly distributed nose cone mass, which assists with stable
rotation of the nose cone 110 during operation. In some embodiments a
plurality
of apertures 160 are provided in nose cone 110.
[0103] Figure 10B is a partial sectional view of the coupling of the nose
cone
of Figure 8 and the hub 120 of Figure 9, shown along axis B, in accordance
with
some embodiments of the present disclosure. Retention lip 137 of bayonet
flange
132 is engaged axially aft of bayonet retainer 142, thus preventing axially
forward
movement of nose cone 110. In some embodiments hub mating surface 118 may
abut rotor 121.
[0104] Figure 10C is a partial sectional view of the coupling of the nose
cone
of Figure 8 and the hub 120 of Figure 9, shown along axis C, in accordance
with
some embodiments of the present disclosure. Pilot flange 133 abuts the axially
extending portion 147 of pilot guide 143 to ensure the proper disposition of
nose
cone 110 relative to hub 120. In rotating embodiments, the abutment of pilot
guide
143 and pilot flange 133 ensures proper concentricity of nose cone 110 to hub
120.
In some embodiments an aperture 148 may be defined by radially extending
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CA 2976726 2017-08-17
portion 146 of the pilot guide 143 and may be configured to receive one or
more
balancing weights 149 which may be coupled to pilot guide 143 with a fastener.
101051 Figure 10D is a partial sectional view of the coupling of the nose
cone
of Figure 8 and the hub 120 of Figure 9, shown along axis D, in accordance
with
some embodiments of the present disclosure. Retention lip 137 of bayonet
flange
132 is engaged axially aft of bayonet retainer 142, thus preventing axially
forward
movement of nose cone 110. In some embodiments hub mating surface 118 may
abut rotor 121. In the embodiment illustrated in Figure 5D, an aperture 160 is
provided through mounting member 113 for the placement of balancing weights
162. A bolt 161 and retaining nut 163 may be used to secure the balancing
weight
162 in position.
101061 Figure 11 is an isometric view of a bayonet flange 132 of a nose
cone
110 in accordance with some embodiments of the present disclosure. In some
embodiments the axially forward facing surface 1109 of retaining lip 137 may
be
laterally or radially tapered. Tapering of the surface 1109 may assist in
engagement between the bayonet flange 132 and bayonet retainer 142. The
tapered surface 1109 may use linear or parabolic tapers. The taper may be
machined into the surface during manufacturing or may be added as a separate
molded part which is bonded to the bayonet flange 132.
CA 2976726 2017-08-17
[0107] In some embodiments of the present disclosure a nose cone assembly
100 is disclosed which eliminates the use of a support ring and fasteners when
coupling nose cone 110 to hub 120 by employing a snap fit configuration. For
example, Figure 12 is an isometric view of a nose cone 110 in accordance with
some embodiments of the present disclosure. Figure 13 is an isometric view of
a
hub 120 configured to be coupled to the nose cone 110 illustrated in Figure
12, in
accordance with some embodiments of the present disclosure.
101081 Nose cone 110 has one or more hub mounting members 1201
extending from a radially inner surface 1202 of flange member 114. In some
embodiments, the at least one hub mounting member 1201 extends from an annular
mounting member 113 which is formed on or integral to the radially inner
surface
1202. In some embodiments a single annular hub mounting member 1201 may be
provided. In other embodiments, such as that illustrated in Figure 12, a
plurality of
distinct hub mounting member 1201 are spaced about the circumference of the
radially inner surface 1202 proximate the base portion 119. In still further
embodiments, the at least one hub mounting member 1201 extends from the
annular hub mating surface 118.
101091 Each hub mounting member 1201 of nose cone 110 comprises a
flexible flange 1203 extending inwardly from flange member 114 and/or mounting
member 113, and a protruding ridge 1204. The protruding ridge 1204 extends
41
CA 2976726 2017-08-17
from a radially outward facing surface 1205 of the flexible flange 1203 and is
configured to be received in a corresponding groove 1305 of the hub 120. In
some
embodiments flexible flange 1203 and/or protruding ridge 1204 include lead-in
features such as a chamfered edge to assist in flexible flange 1203 deflection
upon
engagement with hub 120. In some embodiments protruding ridge 1204 may be
shortened to comprise a protruding nub.
101101 Hub 120 comprises a rotor 121 with a plurality of blades 123
extending radially outward therefrom. The forward portion of the rotor 121 may
comprise a planar mounting surface 145. The axially forward portion of the
rotor
121 comprises an annular mounting portion 1301 which extends radially inward
from rotor 121 and has an annular mounting surface 1303. The annular mounting
surface 1303 defines a one or more grooves 1305 that may be sized and
configured
to receive a protruding ridge 1204 of the nose cone 110. In some embodiments a
single groove 1305 extends continuously about the mounting surface 1303. In
other embodiments, a plurality of discrete grooves 1305 are defined by
mounting
surface 1303.
[0111] In some embodiments annular mounting surface 1303 is a continuous
surface around the circumference of the rotor 121, as shown in Figure 13.
However, in some embodiments the mounting portion 1301 is segmented into a
42
CA 2976726 2017-08-17
plurality of discreet mounting portions 1301 which are spaced about the
circumference of rotor 121.
101121 The nose cone 110 of Figure 12 may be coupled to the hub 120 of
Figure 13. To couple nose cone 110 of Figure 12 to hub 120 of Figure 13 and
achieve a nose cone assembly 100, nose cone 110 is positioned axially forward
of
hub 120 with each of the one or more protruding ridges 1204 axially aligned
with a
respective one of the one or more grooves 1305. Nose cone 110 is then moved
axially aft such that protruding ridges 1204 first contact mounting surface
1303,
causing flexible flanges 1203 to deflect inwardly (i.e. toward the central
axis). As
nose cone 110 continues to be moved axially aft, protruding ridges 1204 engage
grooves 1305, which eases the deflection of flexible flanges 1203. Once
protruding ridges 1204 are engaged with grooves 1305, the axial motion of nose
cone 110 is ceased. In this position flexible flanges 1203 remain deflected
inward
as compared to their non-engaged state shown in Figure 12. This deflection of
flexible flanges 1203 creates strain, which aides in holding nose cone 110 to
hub
120.
101131 Flexible flanges 1203 must be sized and formed of material to
provide
sufficient strain to allow nose cone 110 to remain coupled to hub 120 under
all
operating conditions. In rotating embodiments, centrifugal forces acting on
flexible flange 1203 may impart additional holding force as the flexible
flange
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CA 2976726 2017-08-17
1203 is pushed radially outward and thus exerts increased force on the hub
120.
Additionally, it is noted that the engagement of protruding ridges 1204 to a
respective groove 1305 holds nose cone 110 in a steady circumferential
position
relative to the hub 120.
[0114] The radial displacement force imparted by a deflected flexible
flange
1203 on hub 120 must be sufficient to withstand maximum operating loads. As
with most nose cone designs, this includes the maximum loading experienced
during a bird strike. The flexible flanges 1203 may be configured to impart
sufficient radial displacement force such that decoupling of the nose cone 110
and
hub 120 is only possible under loading from an assembly/disassembly tool. Such
a
tool may engage the nose cone 110 via trim balance apertures 160 in surface
112.
[0115] Figure 14A is a partial sectional view of the nose cone 110 of
Figure
12 coupled to the hub 120 of Figure 13, shown along a plane intersecting one
of
the one or more hub mounting members 1201, in accordance with some
embodiments of the present disclosure. Hub mounting member 1201 comprises
flexible flange 1203 and protruding ridge 1204. As shown in Figure 14A, when
nose cone 110 is properly coupled to hub 120, protruding ridge 1204 is engaged
with groove 1305 and flexible flange 1203 is inwardly deflected as compared to
its
unengaged position in Figure 12.
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[0116] Figure 14B is a partial sectional view of the nose cone 110 of
Figure
12 coupled to the hub 120 of Figure 13, shown along plane which does not
intersect a hub mounting member 1201 but which does intersect an aperture 160,
in
accordance with some embodiments of the present disclosure. In the embodiment
illustrated in Figure 14B, an aperture 160 is provided through flange member
114
and mounting member 113 for the placement of balancing weights 162. A bolt 161
and retaining nut 163 may be used to secure the balancing weight 162 in
position.
During nose cone 110 balancing, balancing weights 162 of varying masses may be
placed in aperture 160 to ensure an evenly distributed nose cone mass, which
assists with stable rotation of the nose cone 110 during operation. In some
embodiments a plurality of apertures 160 are provided in nose cone 110. In
some
embodiments nose cone 110 further defines a countersink 164 around the
aperture
160 configured to receive the balancing weight 162.
[0117] Figure 15 provides a partial profile view of the inner surface of
a rotor
121 having a plurality of discreet mounting portions 1301 according to some
embodiments of the present disclosure. Whereas Figure 13 illustrates a rotor
121
having a continuous mounting portion 1301 and continuous circumferential
groove
1305, the embodiment illustrated in Figure 15 shows a rotor 121 having a
plurality
of discrete mounting portions 1301, with each of the plurality of discrete
mounting
portions defining a respective groove 1305. The view provided in Figure 15 is
CA 2976726 2017-08-17
looking radially outward from the central axis. A plurality of mounting
portions
1301 are formed on and extend inwardly from the inner surface of the rotor
121.
Each mounting portion 1301 comprises a mounting surface 1303 which defines a
groove 1305 configured to receive a corresponding protruding ridge 1204 of
nose
cone 110. In some embodiments, guide channels 1307 are provided which assist
in
guiding a protruding ridge 1204 to the groove 1305. Relative to the depth of
groove 1305, the guide channels 1307 are shallow.
[0118] In some embodiments, the nose cone 110 of Figure 12 and the hub
120 of Figure 13 will further include one or more circumferential alignment
features. For example, in some embodiments one or more mounting flanges 901 as
described above may extend forward from the hub 120 and be joined with a
fastener to nose cone 110 to ensure circumferential alignment of nose cone 110
relative to hub 120. In other embodiments, such as that shown in Figure 16, an
alignment flange 1601 may extend aft from the nose cone 110 and be disposed,
when nose cone 110 is coupled to hub 120, in or between an alignment tab 1602
of
the hub 120.
[0119] Assembly of nose cone 110 to hub 120 may require special tooling.
For example, in some embodiments where nose cone 110 defines a plurality of
apertures 160, it may be desirable to secure positioning rods in one or more
of the
apertures 160 to assist with positioning and moving the nose cone 110 relative
to
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hub 120. In some embodiments an annular tool is contemplated which would
engage simultaneously each of the one or more positioning rods disposed in
apertures 160 to apply equal pressure around the nose cone 110.
[0120] The nose cone and nose cone assemblies presented herein provide
several advantages over the prior art. First, by coupling the nose cone
directly a
hub such as a bladed rotor of a turbine machine, it is possible to eliminate
the
standard support or retaining ring and thus reduce the overall weight of the
unit.
Second, the disclosed nose cone allows for coupling to the hub with a greatly
reduced number of bolts or no bolts at all. Thus, by reducing or eliminating
the
bolts used in the prior art to couple the nose cone to the hub, the weight of
the unit
and the complexity of the coupling process are each reduced.
[0121] In certain of the above embodiments, a system for coupling a nose
cone to a hub is provided which eliminates the need for fingers or flanges
extending axially forward from the hub. Since these fingers or flanges are
difficult
to manufacture with sufficient strength tolerances, their elimination is
advantageous over prior art designs.
[0122] Although examples are illustrated and described herein,
embodiments
are nevertheless not limited to the details shown, since various modifications
and
structural changes may be made therein by those of ordinary skill within the
scope
and range of equivalents of the claims.
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