U.S. patent application number 15/899037 was filed with the patent office on 2018-08-23 for compressor wheel with supports.
This patent application is currently assigned to BorgWarner Inc.. The applicant listed for this patent is BorgWarner Inc.. Invention is credited to Keith Nickson, Tristram Palmer-White.
Application Number | 20180238339 15/899037 |
Document ID | / |
Family ID | 61223802 |
Filed Date | 2018-08-23 |
United States Patent
Application |
20180238339 |
Kind Code |
A1 |
Nickson; Keith ; et
al. |
August 23, 2018 |
Compressor Wheel With Supports
Abstract
In one aspect of the present disclosure, a compressor wheel is
disclosed that includes a body, a plurality of blades, and one or
more supports. The supports add strength to the compressor wheel
and may be configured as ribs, for example. The body has a first
face (e.g., an outer or front face), which may include the blades,
and a second face (e.g. an inner or rear face), which may include
the supports. The supports may include an arcuate configuration
curving forward in a direction of rotation of the compressor
wheel.
Inventors: |
Nickson; Keith;
(Huddersfield, GB) ; Palmer-White; Tristram;
(Bradford, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BorgWarner Inc. |
Auburn Hills |
MI |
US |
|
|
Assignee: |
BorgWarner Inc.
Auburn Hills
MI
|
Family ID: |
61223802 |
Appl. No.: |
15/899037 |
Filed: |
February 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62462070 |
Feb 22, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 5/048 20130101;
F05B 2280/6003 20130101; F05D 2220/40 20130101; F04D 29/266
20130101; F04D 29/284 20130101; F01D 5/282 20130101; F04D 29/023
20130101; F05D 2300/603 20130101 |
International
Class: |
F04D 29/28 20060101
F04D029/28; F04D 29/02 20060101 F04D029/02; F04D 29/26 20060101
F04D029/26 |
Claims
1. A compressor wheel comprising: a body having opposing first and
second faces, and a hub configured and dimensioned for mechanical
connection to a shaft to facilitate rotation of the compressor
wheel about an axis of rotation; a plurality of blades included on
the first face of the body, the blades extending radially outward
from the hub; and a plurality of supports included on the second
face of the body, each of the supports including a first end
positioned adjacent the hub and an opposing second end spaced
radially from the first end, the supports being configured and
dimensioned to transfer torque radially outward across the body to
reduce stress in the body during acceleration of the compressor
wheel.
2. The compressor wheel according to claim 1, wherein the body, the
blades, and the supports are integrally formed.
3. The compressor wheel according to claim 2, wherein the
compressor wheel is formed from a composite material.
4. The compressor wheel according to claim 3, wherein the
compressor wheel is formed from glass-filled nylon.
5. The compressor wheel according to claim 1, wherein each of the
supports includes an arcuate configuration and curves from the
first end to the second end.
6. The compressor wheel according to claim 5, wherein the supports
curve from the first end to the second end in correspondence with a
direction of rotation of the compressor wheel.
7. The compressor wheel according to claim 6, wherein the blades
include an arcuate configuration and curve in a direction opposite
to the supports.
8. The compressor wheel according to claim 6, wherein the supports
each define a thickness extending orthogonally in relation to the
axis of rotation, the thickness being constant between the first
and second ends.
9. The compressor wheel according to claim 6, wherein the supports
each define a thickness extending orthogonally in relation to the
axis of rotation, the thickness varying between the first and
second ends.
10. The compressor wheel according to claim 9, wherein the supports
each include a first section adjacent the first end of the support,
a second section adjacent the second end of the support, and an
intermediate section positioned between the first section and the
second section, the first section defining a first thickness, the
second section defining a second thickness, and the third section
defining a third thickness less than the first thickness and the
second thickness.
11. The compressor wheel according to claim 5, wherein the supports
each define a centerline intersecting the axis of rotation.
12. The compressor wheel according to claim 5, wherein the supports
each define a centerline offset from the axis of rotation such that
the supports extend tangentially in relation to the hub.
13. The compressor wheel according to claim 12, wherein the
supports each include a leading edge and a trailing edge, the
leading edge being spaced a first radial distance from the axis of
rotation and the trailing edge being spaced a second radial
distance from the axis of rotation less than the first radial
distance, the leading edge of each support intersecting the
trailing edge of an adjacent support.
14. A compressor wheel comprising: a body having opposing first and
second faces, and a hub configured and dimensioned for mechanical
connection to a shaft to facilitate rotation of the compressor
wheel about an axis of rotation; a plurality of blades included on
the first face of the body, the blades extending radially outward
from the hub and curving in a first direction; and a plurality of
supports included on the second face of the body, the supports
extending radially outward from the hub and curving in a second
direction opposite the first direction, each of the supports
defining a thickness extending orthogonally in relation to the axis
of rotation.
15. The compressor wheel according to claim 14, wherein the
supports curve in correspondence with a direction of rotation of
the compressor wheel.
16. The compressor wheel according to claim 14, wherein the
thickness of each support is constant.
17. The compressor wheel according to claim 14, wherein the
supports each include first and second ends, the thickness of each
support varying between the first and second ends thereof.
18. The compressor wheel according to claim 17, wherein the
supports each include a first section adjacent a first end of the
support, a second section adjacent an opposing second end of the
support, and an intermediate section positioned between the first
section and the second section, the first section defining a first
thickness, the second section defining a second thickness, and the
third section defining a third thickness less than the first
thickness and the second thickness.
19. A compressor wheel comprising: a body having opposing first and
second faces, and a hub configured and dimensioned for mechanical
connection to a shaft to facilitate rotation of the compressor
wheel about an axis of rotation; a plurality of blades included on
the first face of the body; and a plurality of supports included on
the second face of the body, each of the supports defining a
centerline that is offset from the axis of rotation such that the
supports extend tangentially in relation to the hub.
20. The compressor wheel according to claim 19, wherein the
supports each include a leading edge and a trailing edge, the
leading edge being spaced a first radial distance from the axis of
rotation and the trailing edge being spaced a second radial
distance from the axis of rotation less than the first radial
distance, the leading edge of each support intersecting the
trailing edge of an adjacent support.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of, and priority to,
U.S. Provisional Patent Application Ser. No. 62/462,070, filed on
Feb. 22, 2017, the entire content of which is hererby incorporated
by reference.
BACKGROUND
[0002] Compressor wheels in forced induction devices (e.g.,
turbochargers or superchargers for internal combustion engines)
accelerate at high rates (e.g., up to 200,000 rpm per second) and
rotate in steady state at high speeds (e.g., up to 300,000 rpm),
which can subject the compressor wheel to high stress. For example,
during acceleration, the wheel may be subject to higher torsional
loading and, thereby, higher stress (e.g., shear stress) as torque
is transferred radially outward from the drive shaft through the
compressor wheel. More particularly, as the inner regions of the
compressor wheel move ahead of the outer regions, stress (i.e.,
shear stress) is created and builds in the material comprising the
compressor as torque is transferred radially outward.
[0003] Conventional compressor wheels are typically made of
metallic materials and have a solid body in which the metal
material extends continuously in an axial direction from a first
face (e.g., an outer or front face) to a second face (e.g., an
inner or rear face). In known compressor wheels, the first (outer)
face is generally curved and includes a plurality of blades, while
the second (inner) face is generally planar and/or extends axially
away from the first face. This construction (i.e., materials and
structure) allows conventional compressor wheels to distribute and
manage torsional loading and stress during acceleration.
[0004] Compressor wheels including (e.g., formed from) composite
materials may offer various advantages over metallic compressor
wheels, such as, for example, reduced mass and reduced moment of
inertia, which can facilitate quicker response and/or allow for
reduced motor size (e.g., in electric motor-driven forced induction
devices). Composite compressor wheels, however, may be subject to
different strength considerations. The present disclosure addresses
the concern by providing composite compressor wheels that include
strengthening supports to increase structural rigidity and the
ability of the composite compressor wheels to withstand the
torsional loads and stresses created during acceleration.
SUMMARY
[0005] In one aspect of the present disclosure, a compressor wheel
is disclosed that includes a body, a plurality of blades, and one
or more supports. The supports add strength to the compressor wheel
and may be configured as ribs, for example. The body has a first
face (e.g., an outer or front face), which may include the blades,
and a second face (e.g. an inner or rear face), which may include
the supports. The supports may include an arcuate configuration
curving forward in a direction of rotation of the compressor
wheel.
[0006] In certain embodiments, the body, the blades, and the
supports may be integrally formed. For example, the body, the
blades, and the supports may be injection molded from a composite
material (e.g., glass-filled nylon).
[0007] In certain embodiments, the blades may have a width that
increases from an intermediate region to inner and outer regions
spaced radially inward and outward from the intermediate region,
respectively.
[0008] In certain embodiments, the blades may have a substantially
constant width (e.g., over a majority of a radial length
thereof).
[0009] In certain embodiments, the supports may increase in
thickness moving in an axial direction toward a rear surface of the
rear face of the body.
[0010] In certain embodiments, the supports may have a filleted
transition to the rear face of the body, which may have a
substantially constant radius over a majority of a radial length
thereof.
[0011] In certain embodiments, a radially inner end of each support
may be offset relative to the axis.
[0012] In certain embodiments, the compressor wheel may include a
hub with a shaft coupling that protrudes radially rearward form the
rear face of the body.
[0013] In certain embodiments, the hub and the shaft coupling may
be integrally formed with the body.
[0014] In certain embodiments, a trailing edge of each support may
be positioned in tangential relation to the hub.
[0015] In certain embodiments, an end of the hub may have a
diameter that defines a minimum radial dimension extending across
the hub in perpendicular relation to the axis of rotation.
[0016] In certain embodiments, the trailing edge of each support
may be positioned in tangential relation to the diameter defined by
the end of the hub.
[0017] In certain embodiments, a leading edge of each support may
intersect the trailing edge of an adjacent support.
[0018] In certain embodiments, the diameter of the hub may
intersect the leading edge of one or more of the supports and the
trailing edge of one or more of the supports.
[0019] In certain embodiments, the leading edge may be offset
relative to the axis.
[0020] In certain embodiments, the leading and trailing edges of
each support may be positioned in tangential relation to the hub,
but in opposite directions.
[0021] In certain embodiments, the blades may curve in a direction
opposite to the direction of curvature of the supports.
[0022] In certain embodiments, the body may include one or more
cavities on the rear face thereof located between adjacent
supports.
[0023] In certain embodiments, the compressor wheel may be
incorporated into a forced induction device, such as an exhaust
driven turbocharger.
[0024] In another aspect of the present disclosure, a compressor
wheel is disclosed that includes a body having opposing first and
second faces, and a hub that is configured and dimensioned for
mechanical connection to a shaft to facilitate rotation of the
compressor wheel about an axis of rotation. The compressor wheel
also includes a plurality of blades included on the first face of
the body and extending radially outwardly from the hub, and a
plurality of supports included on the second face of the body.
[0025] Each support includes a first end that is positioned
adjacent to the hub and an opposing second end that is spaced
radially from the first end (i.e., in certain embodiments, the
supports may extend radially outward from the hub). The supports
are configured and dimensioned to transfer torque radially outward
across the body of the compressor wheel to reduce stress in the
body during acceleration.
[0026] In certain embodiments, the body, the blades, and the
supports may be integrally formed.
[0027] In certain embodiments, the compressor wheel may be formed
from a composite material, for example, glass-filled nylon.
[0028] In certain embodiments, each of the supports may include a
first end that is positioned adjacent the hub and an opposing
second end that is spaced radially from the first end. In such
embodiments, each of the supports may be arcuate in configuration
and may curve from the first end to the second end. For example,
the supports may curve from the first end to the second end in
correspondence with a direction of rotation of the compressor
wheel.
[0029] In certain embodiments, the blades may include an arcuate
configuration, and may curve in a direction opposite to the
supports.
[0030] In certain embodiments, the supports may each define a
thickness extending orthogonally in relation to the axis of
rotation. The thickness may be constant or variable between the
first and second ends of the supports. For example, the supports
may each include a first section adjacent the first end of the
support, a second section adjacent the second end of the support,
and an intermediate section positioned between the first section
and the second section, wherein the first section defines a first
thickness, the second section defines a second thickness, and the
third section defines a third thickness that is less than the first
thickness and the second thickness.
[0031] In certain embodiments, the supports may each define a
centerline that intersects the axis of rotation. Alternatively,
however, the supports may each define a centerline that is offset
from the axis of rotation whereby the supports extend tangentially
from the hub.
[0032] In certain embodiments, the supports may each include a
leading edge spaced a first radial distance from the axis of
rotation and a trailing edge spaced a second radial distance from
the axis of rotation less than the first radial distance.
[0033] In certain embodiments, the supports may be configured,
dimensioned, and positioned such that the leading edge of each
support intersects the trailing edge of an adjacent support.
[0034] In another aspect of the present disclosure, a compressor
wheel is disclosed that includes a body having opposing first and
second faces (e.g., outer/front and inner/rear faces), a plurality
of blades included on the first face, and a plurality of supports
included on the second face.
[0035] The body of the compressor wheel also includes a hub that is
configured and dimensioned for mechanical connection to a shaft to
facilitate rotation of the compressor wheel about an axis of
rotation.
[0036] In certain embodiments, the blades may extend radially
outward from the hub and may curve in a first direction (e.g., in
correspondence with a direction of rotation of the compressor
wheel), whereas the supports may extend radially outward from the
hub and may curve in a second direction opposite the first
direction.
[0037] Each of the supports defines a thickness extending
orthogonally in relation to the axis of rotation. In certain
embodiments, the thickness of each support may be constant between
first and second ends thereof. Alternatively, however, the
thickness of each support may vary. For example, in certain
embodiments, the supports may each include a first section adjacent
a first end of the support, a second section adjacent an opposing
second end of the support, and an intermediate section positioned
between the first section and the second section, wherein the first
section defines a first thickness, the second section defines a
second thickness, and the third section defines a third thickness
less than the first thickness and the second thickness.
[0038] In another aspect of the present disclosure, a compressor
wheel is disclosed that includes a body having opposing first and
second faces (e.g., outer/front and inner/rear faces), a plurality
of blades included on the first face, and a plurality of supports
included on the second face.
[0039] The body of the compressor wheel also includes a hub that is
configured and dimensioned for mechanical connection to a shaft to
facilitate rotation of the compressor wheel about an axis of
rotation.
[0040] In certain embodiments, each of the supports may define a
centerline that is offset from the axis of rotation whereby the
supports extend tangentially from the hub.
[0041] In certain embodiments, the supports may each include a
leading edge that is spaced a first radial distance from the axis
of rotation and a trailing edge that is spaced a second radial
distance from the axis of rotation less than the first radial
distance. In such embodiments, the leading edge of each support may
intersect the trailing edge of an adjacent support.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee. The description
herein makes reference to the accompanying drawings, wherein like
referenced numerals refer to like parts throughout several views,
and wherein:
[0043] FIG. 1 is a partial cross-sectional view of a forced
induction device.
[0044] FIG. 2 is a rear, perspective view of an embodiment of a
compressor wheel of the forced induction device of FIG. 1
[0045] FIG. 3 is a front, perspective view of the compressor wheel
of FIG. 2.
[0046] FIG. 4 is a schematic, rear, plan view of the compressor
wheel shown in FIG. 2.
[0047] FIG. 5 is a cross-sectional view of the compressor wheel
taken along line 5-5 in FIG. 4.
[0048] FIG. 6 is a cross-sectional view of the compressor wheel
taken along line 6-6 in FIG. 4.
[0049] FIG. 7 is a cross-sectional view of the compressor wheel
taken along line 7-7 in FIG. 4.
[0050] FIG. 8 is a front, perspective view of an alternate
embodiment of the compressor wheel seen in FIG. 2.
[0051] FIG. 9 is a rear perspective view of an alternate embodiment
of the compressor wheel seen in FIG. 2.
[0052] FIG. 10 is a rear perspective view of another embodiment of
the compressor wheel seen in FIG. 2.
[0053] FIGS. 11A, 11B, and 11C are rear perspective views of the
compressor wheels shown in FIGS. 3, 9, and 10, respectively, which
depict stress in the compressor wheels during acceleration
conditions.
[0054] FIGS. 12A, 12B, and 12C are rear perspective views of the
compressor wheels shown in FIGS. 3, 9, and 10, respectively, which
depict stress in the compressor wheels during steady state
conditions.
[0055] FIGS. 13A, 13B, and 13C are rear perspective views of the
compressor wheels shown in FIGS. 3, 9, and 10, respectively, which
depict displacement of the compressor wheels during steady state
conditions.
DETAILED DESCRIPTION
[0056] The present disclosure describes a compressor wheel for use
in a forced induction device, such as a turbocharger or a
supercharger, which may be formed from non-metallic materials, such
as polymers and/or composite materials. The presently disclosed
compressor wheel is configured and dimensioned to distribute and/or
otherwise manage torsional loading and stress created during
acceleration. More specifically, the compressor wheel includes
strengthening supports that are configured and dimensioned to
transfer torque radially through the compressor wheel, such as, for
example, via compression during acceleration, to reduce stress. The
strengthening supports may be curved and/or linear in
configuration, and may be facilitate uniformity in radial growth of
the compressor wheel in outer portions thereof.
[0057] With reference to FIGS. 1-7, a forced induction device 100
is illustrated that includes a housing 140 and a compressor wheel
210 that is positioned within the housing 140. In use, the forced
induction device 100 may be configured as part of a powertrain of a
vehicle and be arranged to supply compressed air to an internal
combustion engine of the powertrain. The compressor wheel 210 may
be actuated (i.e., rotated) through connection to, or communication
with, any suitable drive source. For example, the compressor wheel
210 may be configured and dimensioned for connection to an electric
motor. Additionally, or alternatively, it is envisioned that the
compressor wheel 210 may be configured, dimensioned, and positioned
for rotation via exhaust gas from the engine (e.g., in the context
of a turbocharger) or via mechanical power transfer from the engine
(e.g., in the context of a supercharger).
[0058] The compressor wheel 210 may be formed from any suitable
material, such as, for example, polymer(s), composite materials,
such as glass-filled nylon, and/or other non-metallic materials. In
certain embodiments, it is envisioned that the compressor wheel 210
may be unitary in construction, and that the compressor wheel 210
may be formed, for example, through a molding process, such as
injection or insert molding.
[0059] The compressor wheel 210 includes a body 212 (FIGS. 2, 3)
having a first (outer/front) face 214 and a second (inner/rear)
face 216. The body 212 includes a hub 217 that facilitates
connection to a drive shaft 152 (FIG. 1) such that the compressor
wheel 210 is rotatable about an axis of rotation 212a (FIG. 2) via
connection to, or communication with, the aforementioned drive
source. In the illustrated embodiment, for example, the hub 217
includes a shaft coupling 218 formed integrally with the body 212
that incorporates an engagement structure 219. In the embodiment
seen in FIGS. 2 and 3, for example, the engagement structure 219
includes a circular bore 219a and a series of recesses 219b that
collectively define a generally cruciform configuration. It should
be appreciated, however, that in alternate embodiments of the
disclosure, the specific configuration and components of the
engagement structure 219 may be varied in alternate embodiments of
the disclosure. For example, it is envisioned that the engagement
structure 219 may include a hexagonal cross-sectional
configuration. Additionally, or alternatively, the engagement
structure 219 may include any structure suitable for the intended
purpose of connecting the drive shaft 152 to the compressor wheel
210 for rotation in the manner described herein, such as, for
example, ribs, detents, etc.
[0060] The hub 217 extends axially with respect to inner and outer
surfaces 216a, 216b of the body 212 so as to define respective
inner and outer faces 217a, 217b having transverse cross-sectional
dimensions (e.g., a diameters) that extends in orthogonal relation
to the axis of rotation 212a. Although illustrated as including a
generally cylindrical configuration in the illustrated embodiments,
whereby the hub 217 defines a circular cross-section, it is
envisioned that the hub 217 may assume alternate geometrical
configurations. For example, it is envisioned that the hub 217 may
be generally frusto-conical in configuration.
[0061] Although the engagement structure 219 is shown and described
as being integrally formed with the hub 217 in the embodiment
illustrated in FIGS. 1-7, in an alternate embodiment, the
engagement structure 219 may be provided on a separate insert that
is configured and dimensioned for receipt by the hub 217. For
example, with reference to FIG. 8, an insert 219c is disclosed that
is positionable within an opening 217c defined by the hub 217. The
insert 219c includes a series of projections 219d that are
configured and dimensioned for engagement with corresponding
projections 217d defined by the hub 217. In such embodiments, it is
envisioned that the insert 219c and the hub 217 may be connected in
any suitable manner, such as, for example, via a press-fit
engagement, welding, etc., and that the hub 217 and the insert 219c
may include any suitable cross-sectional geometry, e.g., square,
hexagonal, flat, etc.
[0062] It is envisioned that the insert 219c may be formed from the
same material as the hub 217 and the compressor wheel 210, or that
the hub 217 and the insert 219c may be formed from different
materials. For example, the hub 217 may be formed from a
non-metallic material, such as glass-filled nylon, whereas the
insert 219c may be formed from a metallic material, such as
aluminum, steel, etc.
[0063] It is envisioned that the insert 219c may serve as a
compression limiter to reduce or eliminate load on the hub 217.
Additionally, it is envisioned that the insert 219c may increase
achievable tip speeds by reducing bore stress on the hub 217.
[0064] With reference again to FIGS. 1-7, the outer face 214 of the
body 212 includes (e.g., defines or forms) the outer surface 216a
(FIG. 3), and is generally convex in configuration. The outer face
214 includes a plurality of blades 220 that extend outwardly from
the outer surface 214a. The blades 220 are configured and
dimensioned to draw air from an intake (not shown) and compress the
air such that it is expelled from an outlet (not shown) at a higher
pressure for forced induction into an internal combustion engine,
for example. It is envisioned that the plurality of blades 220 may
be formed integrally with the body 212 (e.g., as part of the
molding process), and thus, that the blades 220 and the body 212
may be formed from the same material. Alternatively, it is
envisioned that the blades 220 may be formed separately from the
body 212 and attached thereto, such as, for example, via welding.
In such embodiments, the body 212 and the blades 220 may be formed
from the same or different materials.
[0065] In certain embodiments, the blades 220 may include a curved
configuration, as shown in FIG. 3, for example. More particularly,
it is envisioned that the curvature of the blades 220 may oppose
the direction of rotation of the compressor wheel 210, which is
indicated by arrow 1, or that the curvature of the blades 220 may
be configured in correspondence with the direction of rotation of
the compressor wheel 210.
[0066] The inner face 216 of the body 212 includes (e.g., defines
or forms) the inner surface 216b, and approaches/intersects the
outer face 214 an outer periphery 215 of the body 212. The inner
face 216 is generally concave in configuration, and includes one or
more supports 222, as well as one or more recess 224. The
recess(es) 224 extend between adjacent supports 222 and are
collectively defined by the inner surface 216a, the hub 217, and
the supports 222. In certain embodiments, it is envisioned that the
recesses 224 may reduce the overall wall thickness, and thus, the
overall weight of the body 212, and/or that the recesses 224 may be
positioned to increase consistency in the wall thickness of the
body 212, which may be advantageous in forming the compressor wheel
210 using an injection molding process. The recesses 224 may thus
"hollow" the body 212 in contrast to the solid design employed in
many known conventional compressor wheels, as described above.
[0067] The supports 222 are configured, dimensioned, and positioned
to transfer torque radially outward across the body 212 of the
compressor wheel 210 so as to reduce stress in the body 212 during
acceleration. Although configured as a plurality of ribs in the
illustrated embodiments, the supports 222 may assume any
configuration suitable for the intended purpose of transferring
torque radially outward in the manner described herein, such as,
for example, struts, brackets, walls, etc.
[0068] It is envisioned that the supports 222 may be formed
integrally with the body 212 (e.g., as part of the molding
process), as illustrated in FIGS. 2 and 3, for example, and thus,
that the supports 222 and the body 212 may be formed from the same
material. Alternatively, it is envisioned that the supports 222 may
be formed separately from the body 212 and attached thereto, such
as, for example, via welding. In such embodiments, it is envisioned
that the body 212 and the supports 222 may be formed from the same
or different materials. As seen in FIGS. 2 and 3, forming the
supports 222 integrally with the body 212 eliminates any physical
division between the hub 217 and the supports 222, whereby the
transverse cross-sectional dimension of the hub 217 (e.g., the
diameter) acts as an imaginary dividing line separating the hub 217
from the supports 222.
[0069] Each of the supports 222 each includes a first end 222a
positioned adjacent (e.g., coupled to or formed integrally with)
the hub 217 and a second end 222b spaced radially from the first
end 222a. It is envisioned that ends 222b of the supports 222 may
extend into an outer/peripheral region of the compressor wheel 210,
as shown in FIG. 2, for example, or alternatively, that the ends
222b may extend to the outer periphery 215 of the body 212. The
supports 222 each define a first edge 222c (e.g., an inner or
leading edge) spaced a first radial distance R1 (FIG. 4) from the
axis of rotation 212a, a second edge 222d (e.g., an outer or
leading edge) spaced a second radial distance R2 from the axis of
rotation 212a that is greater than the first distance, and a
centerline 222e positioned equidistant from the first edge 222c and
the second edge 222d.
[0070] As shown in FIG. 2, for example, it is envisioned that the
supports 222 may be spaced evenly across the inner face 216. For
example, the compressor wheel 210 may include four supports 222
spaced at 90-degree intervals. In alternate embodiments, however,
the number of supports 222 included on the compressor wheel 210 may
be varied. For example, the compressor wheel 210 may include three
supports 222 spaced at 120-degree intervals, five supports 222
spaced at 72-degree intervals, etc.
[0071] In one embodiment, the supports 222 may include a curved
configuration, as shown in FIG. 2, for example. More particularly,
it is envisioned that the supports 222 may curve in the direction
of rotation of the compressor wheel 210, which indicated by arrow 1
in FIG. 2, or alternatively, that the supports 222 may curve in a
direction opposite that of rotation of the compressor wheel 210. It
is envisioned that the curvature of the supports 222 may be chosen
to facilitate the transfer of torque radially outward during
acceleration of the compressor wheel 210 as a compressive load
along the supports 222. As can be appreciated through reference to
FIGS. 2 and 3, it is envisioned that the curvature defined by the
supports 222 may be opposite that defined by the blades 220.
[0072] It is envisioned that the configuration, dimensions, and
positions of the supports 222 may be varied in alternate
embodiments of the compressor wheel 210. For example, based upon
the desired performance of the compressor wheel 210 and/or the
loads/stresses experienced by the compressor wheel 210 during
operation, the curvature, cross-sectional shape, and/or location of
the supports 222 may be varied. In particular, the curvature of the
supports 222 may be varied such that, during acceleration, the
supports 222 are loaded primarily in compression and minimize any
bending load or moment. The curvature of the supports 222 may also
be chosen to inhibit or prevent drawing lubricants (e.g., oil or
grease) from bearings positioned adjacent the inner face 216 of the
compressor wheel 210 (e.g., by creating a small positive pressure
on the second face 216).
[0073] As shown in FIG. 2, it is envisioned that the supports 222
may define a thickness T that varies between the ends 222a, 222b.
For example, the supports 222 may each include a first portion 223a
adjacent the end 222a defining a first thickness Ta, a second
portion 223b adjacent the end 222b defining a second thickness Tb,
and one or more intermediate portions 223c positioned between the
portions 223a, 223b defining a third thickness Tc. In the
particular embodiment shown in FIG. 2, for example, the supports
222 are configured and dimensioned such that the thickness Ta is
greater than the thickness Tb, whereby the supports 222 widen to
define a fillet adjacent the hub 217, but less than the thickness
Tc. It should be appreciated, however, that in alternate
embodiments, the thicknesses Ta, Tb, Tc may be altered or varied to
achieve any desired effect or to apply structural support to the
compressor wheel 210 as needed. For example, the thicknesses Ta,
Tb, Tc may be equivalent to each other, the thickness Ta may exceed
the thickness Tc, etc. It is envisioned that increasing the
thickness of the supports 222 adjacent the ends 222b may offset a
reduction in material used in construction of the blades 220 (e.g.,
to further limit stress concentrations).
[0074] Although shown as including first, second, and third
portions in FIG. 2, it should be appreciated that the number of the
portions may be increased or decreased in alternate embodiments of
the disclosure.
[0075] With continued reference to FIG. 2, it is envisioned that
the supports 222 may define a curvature with a substantially
constant radius (e.g., a simple curve) over a majority of the
length of the support 222 (e.g., 50% or more of the overall length
of the support 222). Alternatively, is envisioned that the
curvature of the supports 222 may vary between the ends 222a, 222b.
For example, in one embodiment, the curvatures of the portion 223a,
223b, 223c may be unequal (e.g. the curvature of the portion 223a
may exceed the curvature of the portion 223b which may exceed the
curvature of the portion 223c). It is envisioned that the curvature
of the supports 222 may be defined as elliptical or exponential
curvature, or any other suitable shape.
[0076] With reference to FIGS. 4-7, the supports 222 define a
height H that may be varied between the ends 222a, 222b. For
example, in the illustrated embodiment it is envisioned that the
height H may decrease from the end 222a to the end 222b. It is
envisioned that the variation in height H may be gradual, such that
the supports 222 include a generally "tapered" configuration, as
illustrated in FIGS. 5-7, for example, or that the height H may be
reduced incrementally in step-wise fashion.
[0077] Dependent upon the desired operation and structural
reinforcement provided by the supports 222, it is envisioned that
the specific location and/or orientation of the supports 222 may be
varied. For example, with reference to FIG. 4, the supports 222 may
be positioned such that the centerlines 222e are offset or spaced
radially from the axis of rotation 212a, whereby the supports 222
extend tangentially from the hub 217. Alternatively, it is
envisioned that the supports 222 may be positioned such that the
centerlines 222e intersect the axis of rotation 212a. As seen in
FIG. 4, in certain embodiments, the supports 222 may be positioned
such that the edges 222d intersect, or are otherwise joined to, the
edges 222c of adjacent supports 222.
[0078] As discussed above, the supports 222 reduce stress in the
body 212 during acceleration when compared to similarly configured
compressor wheels without such supports 222, and the effect of
these stress reductions is amplified by the curvature of the
supports 222. FIG. 11A provides an illustration of a computer
simulation performed with respect to the compressor wheel 210
illustrated in FIGS. 2 and 3, for example, whereas FIG. 11B
provides an illustration of a computer simulation performed with
respect to a similar compressor wheel 310 that is devoid of the
supports 222, and FIG. 11C provides an illustration of a computer
simulation performed with respect to a similar compressor wheel 410
that includes linear supports 422.
[0079] The simulations reflected in FIGS. 11A-11C were performed in
both accelerating and steady state conditions for the compressor
wheels 210, 310, and 410 to determine stress concentrations. During
the simulations, the respective outer peripheries 215, 315, 415 of
the compressor wheels 210, 310, 410, were held in place while
torque was applied to the respective hubs 217, 317, 417. The
regions having different shading indicate different levels of
stress (see the legend associated with FIG. 11A). As shown in FIG.
11B, the compressor wheel 310 experiences large stress
concentrations of greater than 200 MPa in areas surrounding the hub
317, as well as in inner regions of the body 312, which are reduced
gradually as the radial distance from the hub 317 is increased.
Stress reduction is also visible in regions associated with the
blades 320. As shown in FIG. 11C, the compressor wheel 410 also
experiences large stress concentrations of greater than 200 MPa in
areas surrounding the hub 417, as well as in inner regions of the
body 412, and in the areas of transition between the supports 422
and the body 412. In contrast, as shown in FIG. 11A, the compressor
wheel 210 experiences substantially smaller stress concentrations
of greater than 200 MPa, which are localized to the areas of
transition between the supports 222 and the hub 217.
[0080] FIGS. 12A-12C provide illustrations of computer simulations
performed in steady state conditions in which the hubs 217, 317,
417 were restrained and a 1-bar load, representative of aerodynamic
loading, was applied the blades 220, 320, 420 in conjunction with a
centrifugal load of 70,000 RPM. As shown in FIG. 12B, the
compressor wheel 310 experienced the lowest magnitude stress
concentrations, peaking at approximately 70,000 MPa. As shown in
FIG. 12C, however, the compressor wheel 410 experienced peak stress
concentrations of approximately 100,000 MPa in the areas of
transition between the supports 422 and the body 412 (e.g., as the
supports 422 constrain radial growth of the body 412). As shown in
FIG. 12A, the compressor wheel 210 also experienced peak stress
concentrations of approximately 100,000 MPa in the areas of
transition between the supports 222 and the body 212 with the
highest stress concentrations being located in outer regions of the
compressor wheel 210 (e.g., as the supports 222 expand radially
outward in an attempt to straighten).
[0081] FIGS. 13A-13C provide illustrations of computer simulations
performed in steady state conditions to identify and measure radial
displacement (e.g., growth) experienced by the compressor wheels
210, 310, 410. In FIGS. 13A-13C, regions having different shading
indicate different amounts of radial growth (see the legend
associated with FIG. 13A). As compared to metallic compressor
wheels, growth of polymer or composite compressor wheels may be up
to 20 times greater. As shown in FIG. 13B, the compressor wheel 210
experiences generally even radial growth. Aerodynamic loading of
the blades 220, for example, tends to compress the compressor wheel
210 radially inward, so as to partially offset centrifugal forces.
As shown in FIG. 13C, the compressor wheel 410 experiences uneven
radial growth with the supports 422 constraining growth at
90-degree intervals. As shown in FIG. 13A, the compressor wheel 210
experiences generally even radial growth but in slightly greater
magnitude than the compressor wheel 310.
[0082] The simulations reflected in FIGS. 11A-13C illustrate that
the compressor wheel 210 experienced substantial reductions in
stress when compared to the compressor wheels 310, 410 during
acceleration, but higher stresses than the compressor wheel 310
during steady state conditions. Additionally, the simulations
illustrate that the compressor wheel 210 experienced slightly
greater radial growth than the compressor wheel 310, and
substantially more uniformity in radial growth than the compressor
wheel 410, during steady state rotation. As a result, the
compressor wheel 210 may provide a better compromise of stress in
acceleration and steady state conditions, while providing generally
even radial growth, which may be provide better durability and/or
fatigue life of the compressor wheel 210. Furthermore, the use of
curved supports 222 may be particularly advantageous in different
applications, such as in exhaust-driven turbochargers, that operate
the compressor wheel 210 at higher pressures and/or at higher
temperatures (e.g., as compared to electronic or mechanically
driven forced induction devices) that may cause greater stress
and/or shape distortion.
[0083] It is to be understood that the present disclosure is not to
be limited to the disclosed embodiments but, on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the scope of the appended claims, which scope is to
be accorded the broadest interpretation so as to encompass all such
modifications and equivalent structures as is permitted under the
law. For example, the elements and features shown or described in
connection with one embodiment may be combined with those of
another embodiment without departing from the scope of the present
disclosure.
[0084] In the preceding description, reference may be made to the
spatial relationship between the various structures illustrated in
the accompanying drawings, and to the spatial orientation of the
structures. However, as will be recognized by those skilled in the
art after a complete reading of this disclosure, the structures
described herein may be positioned and oriented in any manner
suitable for their intended purpose. Thus, the use of terms such as
"above," "below," "upper," "lower," "inner," "outer," etc., should
be understood to describe a relative relationship between
structures, and/or a spatial orientation of the structures.
[0085] Additionally, terms such as "approximately" and "generally"
should be understood to allow for variations in any numerical range
or concept with which they are associated. For example, it is
envisioned that the use of terms such as "approximately" and
"generally" should be understood to encompass variations on the
order of 25%, or to allow for manufacturing tolerances and/or
deviations in design.
* * * * *