U.S. patent application number 10/196268 was filed with the patent office on 2004-01-22 for ring cooling fan including stiffening ribs fully connected on at most two sides.
This patent application is currently assigned to Hayes Cooling Technologies, LLC. Invention is credited to Nilson, Carl A..
Application Number | 20040013526 10/196268 |
Document ID | / |
Family ID | 30442786 |
Filed Date | 2004-01-22 |
United States Patent
Application |
20040013526 |
Kind Code |
A1 |
Nilson, Carl A. |
January 22, 2004 |
Ring cooling fan including stiffening ribs fully connected on at
most two sides
Abstract
A process of producing a ring cooling fan, the ring cooling fan
including at least two fan blades, a fan hub, and a fan ring. Each
of the fan blades has a distal end disposed away from the fan hub
and connected with one another via the fan ring and a proximal end
disposed on the fan hub. At least one of the fan blades includes at
least two stiffening ribs in an open-box structure. The process
includes disposing the fan hub in a mold, molding the at least two
fan blades and the fan ring such that the stiffening ribs are
disposed on a top surface of the fan blade and are fully connected
with each other on at most two sides, and removing the ring cooling
fan from the mold.
Inventors: |
Nilson, Carl A.; (Jackson,
MI) |
Correspondence
Address: |
Carl A. Nilson
2966 Wolhaven
Jackson
MI
49201
US
|
Assignee: |
Hayes Cooling Technologies,
LLC
Ann Arbor
MI
|
Family ID: |
30442786 |
Appl. No.: |
10/196268 |
Filed: |
July 17, 2002 |
Current U.S.
Class: |
416/189 ;
416/236R |
Current CPC
Class: |
F04D 29/326 20130101;
F04D 29/329 20130101 |
Class at
Publication: |
416/189 ;
416/236.00R |
International
Class: |
F04D 029/38 |
Claims
What we claim is:
1. A process of producing a ring cooling fan, the ring cooling fan
comprising at least two fan blades, a fan hub, and a fan ring, each
of the fan blades having a distal end disposed away from the fan
hub and connected with one another via the fan ring and a proximal
end disposed on the fan hub, at least one of the fan blades
including at least two stiffening ribs, the process comprising:
disposing the fan hub in a mold; molding the at least two fan
blades and the fan ring, such that the stiffening ribs are disposed
on a surface of the fan blade and are fully connected with each
other on at most two sides; and removing the ring cooling fan from
the mold.
2. The process according to claim 1, wherein the stiffening ribs
are disposed along a radius of the fan hub.
3. The process according to claim 1, wherein the stiffening ribs
are disposed at an angle to a radius of the fan hub.
4. The process according to claim 3, wherein the stiffening ribs
are substantially parallel with each other.
5. The process according to claim 1, wherein the stiffening ribs
have an open-box structure which is open on two full sides.
6. The process according to claim 1, wherein four stiffening ribs
are present.
7. The process according to claim 1, further comprising: molding at
least two additional stiffening ribs on the surface of at least one
fan blade opposite the surface on which the original stiffening
ribs are disposed.
8. A ring cooling fan produced by the process of claim 1.
9. A ring cooling fan produced by the process of claim 5.
10. A ring cooling fan produced by the process of claim 6.
11. A ring cooling fan, comprising: a fan ring; a fan hub
comprising a top surface and a bottom surface disposed apart from
the top surface along an axis of rotation of the ring cooling fan
for connection with a drive shaft or clutch body; a first fan blade
including a first distal end and a first proximal end opposite the
first distal end and connected with the fan hub; a second fan blade
including a second distal end and a second proximal end opposite
the second distal end and connected with the fan hub, the first and
second distal ends of the fan blades being connected with each
other via the fan ring; and at least two stiffening ribs disposed
on the first fan blade, the stiffening ribs being fully connected
with each other on at most two sides.
12. The ring cooling fan according to claim 11, wherein at least
one of the stiffening ribs extends along a radius of the fan
hub.
13. The ring cooling fan according to claim 11, wherein at least
one of the stiffening ribs extends at an angle to a radius of the
fan hub.
14. The ring cooling fan according to claim 11, wherein the
stiffening ribs are parallel with each other.
15. The ring cooling fan according to claim 11, wherein the first
fan blade includes a fan blade top surface disposed at a blade
angle from and adjacent to the top surface of the fan hub, the
stiffening ribs extending from the fan blade top surface to the top
surface of the fan hub.
16. The ring cooling fan according to claim 15, wherein four
stiffening ribs are present.
17. The ring cooling fan according to claim 16, further comprising:
at least one bottom stiffening rib disposed on a bottom surface of
the first blade opposite the top surface.
18. The ring cooling fan according to claim 17, wherein two
stiffening ribs are present on the bottom surface.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a ring cooling fan, and,
more specifically, to a ring cooling fan including stiffening ribs
fully connected on at most two sides (e.g., stiffening ribs having
an open-box structure with more than one full side open, such that
excess material is absent from a full top side and at least a
portion of another side of the stiffening ribs structure).
BACKGROUND OF THE INVENTION
[0002] In an internal combustion engine (e.g., a diesel or a
gasoline engine), a ring cooling fan including multiple fan blades
or impellers that draw and/or push air through a heat conducting
radiator can be used to regulate the temperature of an engine
coolant that cools the engine. As the performance level of the
engine increases and/or the size of the engine compartment that
houses the fan decreases, cooling requirements of the fan
increase.
[0003] The revolution rate of the fan blades can be increased to
increase the cooling rate of the engine coolant. However, because a
fan that is revolved at a higher rate undergoes increased stresses
and strains, the fan can warp or suffer catastrophic failure or
"bursting" during operation, significantly and adversely affecting
engine performance.
[0004] To avoid such adverse effects, stiffened portions in the
form of a closed-box structure can be used on the fan blades at a
location where the fan blades are molded on a center fan hub. In
conjunction with the outer ring, such portions prevent warpage and
bursting of the blades of the ring fan over a larger range of
operating conditions and at higher rates of revolution. FIGS. 5a
and 5b show an example of such a ring fan. As exemplified in FIGS.
5a and 5b, the ring fan 10 includes stiffeners 20 that are
configured as the closed-box structure, such that the stiffeners 20
are fully connected on at least three sides (e.g., each of the two
stiffeners 20 and the three connecting sides forms a full face of a
cuboid structure), thereby forming a box that has only one side
open. It has been found that such a closed-box structure 20 permits
operation of the ring fan 10 at higher rates of revolution than a
ring fan without such a structure while substantially impeding
warpage and bursting of the blades 30.
[0005] The ring fan 10 is produced by an injection molding process.
In such a process, the number of fans that can be produced by a
single molding machine is proportional to the process time for
injection of the molten plastic and cooling of the injection molded
part. Accordingly, it is desirable to reduce the cooling time for
the fan produced by a molding machine. For these reasons, it is
desirable to produce a ring fan that is sufficiently rigid to
preclude warpage and bursting during operation, while at the same
time decreasing the cooling time and thereby allowing the ring fan
to be produced in a more economical manner.
SUMMARY OF THE INVENTION
[0006] The present invention provides a process of producing a ring
cooling fan, the ring cooling fan including at least two fan
blades, a fan hub, and a fan ring. Each of the fan blades has a
distal end disposed away from the fan hub and connected with one
another via the fan ring and a proximal end disposed on the fan
hub. At least one of the fan blades includes at least two
stiffening ribs in an open-box structure. The process includes
disposing the fan hub in a mold, molding the at least two fan
blades and the fan ring such that the stiffening ribs are disposed
on a top surface of the fan blade and are fully connected with each
other on at most two sides, and removing the ring cooling fan from
the mold. In a preferred embodiment, the stiffening ribs and the at
most two connecting sides each form full faces of a cuboid
structure, thereby forming the open-box structure that is open on
more than one full side (e.g., open on one full side and at least a
portion of another side), and more preferably, is open on two full
sides. The stiffening ribs are preferably connected with or to each
other via the structure of the fan blades. The present invention
also provides a ring cooling fan produced by such a process.
[0007] The present invention further provides a ring cooling fan. A
fan hub includes a top surface and a bottom surface disposed apart
from the top surface along an axis of rotation of the ring cooling
fan for connection with a drive shaft or clutch body. A first fan
blade includes a first distal end and a first proximal end opposite
the first distal end and connected with a fan hub. A second fan
blade includes a second distal end and a second proximal end
opposite the second distal end and connected with the fan hub, the
first and second distal ends of the fan blades being connected with
each other via the fan ring. At least two stiffening ribs are
disposed on the first fan blade in an open-box structure, the
stiffening ribs being fully connected with each other on at most
two sides. In a preferred embodiment, the stiffening ribs and the
at most two connecting sides each form full faces of a cuboid
structure, thereby forming the open-box structure that is open on
more than one full side (e.g., open on one full side and at least a
portion of another side), and more preferably, is open on two full
sides.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] A more complete appreciation of the present invention and
many of the attendant advantages thereof will be readily obtained
as the same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings, wherein:
[0009] FIG. 1 shows a bottom isometric view of the ring cooling fan
of the present invention.
[0010] FIG. 2 shows a detail isometric view of the bottom of the
ring cooling fan.
[0011] FIG. 3 shows a top view of the ring cooling fan.
[0012] FIG. 4 shows a detail isometric view of the top of the ring
cooling fan.
[0013] FIGS. 5a and 5b show top and bottom views, respectively, of
a ring cooling fan having a closed-box structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Examples of preferred embodiments of the present invention
will now be described with reference to the drawings, wherein like
reference numbers throughout the several views identify like
elements. FIGS. 1-4 show an example of a ring cooling fan according
to the present invention.
[0015] In a broad embodiment, the ring cooling fan 10 includes
stiffening ribs 20 that are disposed on a surface of a fan blade 40
and fully connected with each other on at most two sides, such that
two stiffening ribs 20 and the at most two connecting sides (e.g.,
other structure of the ring cooling fan 10) each form a full face
of a cuboid structure, thereby forming an open-box structure that
is open on more than one full side (e.g., open on one full side and
at least any non-zero portion of another side). In a preferred
embodiment, two sides of the open-box structure are fully open.
However, it is to be understood that the open-box structure
includes, for example, the structure that is open on one full side
and that is open on another side at least between about 10 and 100
percent (i.e., is closed between about 0 and 90 percent) of a
corresponding length of at least one of the stiffening ribs. In a
more preferred embodiment, the open-box structure is open on one
full side and is open on another side at least between about 50 and
100 percent (i.e., is closed between about 0 and 50 percent), and,
in a still more preferred embodiment, is open on the other side
between about 75 and 100 percent (i.e., is closed between about 0
and 25 percent). However, it is to be understood that the open-box
structure includes the structure that is open on one full side and
that is open on another side within any ranges and/or subranges
discussed above. Disposing the stiffening ribs 20 on the surface of
the fan blade 40 is to be understood to include the use of at least
one surface of the fan blade 40 as the connecting side so as to
preclude requiring additional structural features (e.g., an
additional rib attachment ring) between the at least one surface of
the fan blade 40 and the stiffening ribs 20. By this arrangement,
excess structure associated with an additional attachment ring, for
example, can be eliminated. This arrangement results in a reduced
volume of plastic between successive fan blades 40 and/or between
the stiffening rib 20 and the fan blade 40. In a preferred
embodiment, the stiffening ribs 20 are disposed on the surface of
the fan blade 40 that is parallel to an axis of rotation of the
ring cooling fan 10. Fully connected stiffening ribs 20 are to be
understood to include a connection between at least a portion of a
length of the stiffening rib 20 and a full length of the connecting
side, as well as a full length of the stiffening rib 20 and at
least a portion of the length of the connecting side. Such an
arrangement facilitates removal of the ring cooling fan 10 from a
mold during a molding process, decreases cooling time in the mold
of the ring cooling fan 10 during the injection molding process,
and/or prevents sticking and pull-outs of the stiffening ribs
20.
[0016] As exemplified in the drawings, the preferred ring cooling
fan 10 includes the stiffening ribs 20, a fan hub 30, a plurality
(i.e., at least two (2), preferably six (6), and more preferably
ten (10) or more) of the fan blades 40, and a fan ring 50 (each
discussed below).
[0017] In a broad embodiment, the fan hub 30 couples the fan blades
40 with a ring cooling fan drive shaft (not shown) or clutch body
(not shown). By this arrangement, a rotation of the drive shaft or
clutch body results in a corresponding revolution of the fan blades
40/ring cooling fan 10. It is to be understood that although the
fan hub 30 and its associated structure shown in the drawing
figures exemplifies preferred embodiments, the fan hub 30 can
include any structure so long as the fan hub 30 couples with the
fan blades 40 for rotation.
[0018] As exemplified in the drawings, the fan hub 30 has a top
surface 31 and a bottom surface 33 that is offset from the top
surface 31 along an axis of rotation of the fan hub 30/the ring
cooling fan 10. Each of the top and bottom surfaces 31, 33, have a
generally circular cross section, and include portions that are
disposed on successive parallel planes (i.e., neither of the top
and bottom surfaces 31, 33, are required to lie entirely on a
single plane). By this arrangement, in a preferred embodiment, the
fan hub 30 is generally cup-shaped.
[0019] As exemplified in the figures, a plurality of about-circular
holes 35 is used to connect the fan hub 30 with the drive shaft or
clutch body. The plurality of about-circular holes 35 is preferably
about equally spaced on the fan hub 30. In a preferred embodiment,
the plurality of about-circular holes 35 includes four (4) holes
that are disposed about 90 degrees apart. The fan hub 30 can also
include a plurality of radial slots 37. The radial slots 37 permit
dissipation of heat from the clutch body. The plurality of radial
slots 37 is about equally spaced on the fan hub 30. In a preferred
embodiment, the plurality of radial slots 37 includes four (4)
slots that are disposed about 90 degrees apart.
[0020] Optionally, the fan hub 30 can include interface holes (not
shown) disposed on an outer diameter thereof. The interface holes
can be used for flow through of liquid plastic during the molding
process. By this arrangement, the fan blades 40 can be secured to
the fan hub 30. In a preferred embodiment, the fan hub 30 includes
thirty six (36) such interface holes, each having a diameter of
between 11 and 12 mm. However, it is to be understood that the any
number of interface holes of any size can be disposed at a variety
of positions on along the diameter of the fan hub 30. It is to be
further understood that satisfactory attachment of the fan blades
40 with the fan hub 30 can be achieved in the absence of interface
holes on the fan hub 30.
[0021] The fan hub 30 can be of a variety of materials, including
plastics and metals. In a preferred embodiment, the fan hub 30 is a
metal capable of being disposed in a mold, such that at least a
portion of the ring cooling fan 10 can be molded directly thereon.
Specifically, the material can be steel, such as 050 YHK hot roll
steel, aluminum, or glass filled nylon. However, it is to be
understood that the fan hub 30 can be of any material able to
substantially impede bursting under the desired operating
conditions of the ring cooling fan 10.
[0022] In a broad embodiment, the plurality (i.e., at least two) of
the fan blades 40 is connected with the fan hub 30, such that the
fan blades 40 effectively cool the engine. As exemplified in the
drawings, in a preferred embodiment, the plurality of fan blades 40
includes ten (10) fan blades 40. It is to be understood that
although the fan blades 40 and their associated structure shown in
the drawing figures exemplify preferred embodiments, the fan blades
40 can include any structure so long as the fan blades 40
effectively cool the engine.
[0023] As exemplified in the drawings, each of the fan blades 40
includes a proximal end 41 and a distal end 43 that is disposed
apart from the proximal end 41. Contours of the top blade surface
45 and the bottom blade surface 47 are selected based on the
desired operating conditions and cooling requirements of the ring
cooling fan 10. As exemplified in the figures, at least two, and
preferably, all of the distal ends 43 of the fan blades 40 are
connected to each other via the fan ring 50.
[0024] In a broad embodiment, the fan ring 50 connects at least two
of the fan blades 40, thereby permitting desired operation of the
ring cooling fan 10. Although the drawings show preferred
embodiments of the fan ring 50 having a rectangular cross section
and connecting each of the distal ends of the fan blades 40, it is
to be understood that the fan ring 50 can be of any cross-sectional
shape, and can connect any of a plurality (i.e., at least two) of
the fan blades 40 at any location along the length of the fan
blades 40.
[0025] In a broad embodiment, the stiffening ribs 20 are disposed
on a surface of a fan blade 40 and fully connected to each other on
at most two sides, such that two stiffening ribs 20 and at most two
connecting sides form full faces of the cuboid structure, thereby
forming an open-box structure that is open on more than one full
side (e.g., open on one full side and at least a portion of another
side, and preferably open on two full sides). As discussed above,
disposing the stiffening ribs 20 on the surface of the fan blade 40
is to be understood to include the use of at least one surface of
the fan blade 40 as the connecting side so as to preclude requiring
additional structural features (e.g., an additional rib attachment
ring) between the at least one surface of the fan blade 40 and the
stiffening ribs 20. For example, as shown in the drawings, in a
preferred embodiment, the stiffening ribs 20 are connected with or
to each other via a side surface of the fan blades 40, the side
surface being parallel to the axis of rotation of the ring cooling
fan 10. The open-box structure including stiffening ribs disposed
on the surface of the fan blades provides a number of advantages
over a closed-box structure having a single open side as depicted
in FIGS. 5a and 5b. It is believed that the closed-box structure
acts as an insulator by restricting heat flow away from features of
the mold. The open-box structure reduces cooling time and therefore
process cycle time by increasing heat flow away from the features
of the mold. Thus, by this arrangement, removal of the ring cooling
fan 10 from the mold is facilitated, cooling time in the mold of
the ring cooling fan 10 during the injection molding process is
decreased, and/or sticking and pull-outs of the stiffening ribs 20
is prevented. Generally, it is believed that these advantages are
inversely proportional to a size of a wall formed on the open sides
of the open-box structure (i.e., that these advantages decrease
when the open-box structure is open on one full side and a
relatively small portion of another side), and therefore are
maximized when both sides of the open-box structure are fully
open.
[0026] As exemplified in the drawings, in a preferred embodiment,
the stiffening ribs 20 are used on both top and bottom surfaces of
the ring cooling fan 10. However, it is to be understood that the
stiffening ribs 20 can be used on either or both sides of the fan
blades 40.
[0027] In a preferred embodiment exemplified in the drawings, the
top stiffening ribs 21 extend from the top surface 31 of the hub
ring 30 to the top blade surface 45 along the axis of rotation of
the ring cooling fan 10 and extend along a radius of the fan hub
30/the ring cooling fan 10 to an edge of the proximal end of the
fan blade 40. The heights of the top stiffening ribs 21 can vary
from each other, such that each of the top stiffening ribs 21 has a
different height, and are preferably arranged in order of ascending
or descending height. The number, size, shape, spacing,
orientation, and material of the top stiffening ribs 21 can be
selected such that the desired characteristics of the ring cooling
fan 10 are achieved. For example, one or more of the top stiffening
ribs 21 can be disposed at an angle to the radius of the fan hub
30, and one or more of the top stiffening ribs 21 can be disposed
about parallel with at least one other top stiffening rib 21.
Alternatively, all of the top stiffening ribs 21 can be disposed in
any orientation, and can be disposed in different orientations
relative to one another. Further, any number of the top stiffening
ribs 21 can be used. In a preferred embodiment, three (3) to six
(6) such top stiffening ribs 21 are used, and more preferably four
(4) such top stiffening ribs 21 are used.
[0028] Similarly, bottom stiffening ribs 23 preferably extend from
the bottom surface 33 to the bottom blade surface 47 along the axis
of rotation of the ring cooling fan 10 and extend along the radius
of the hub ring 30/the ring cooling fan 10 to the edge of the
proximal end of the fan blade 40. The heights of the bottom
stiffening ribs 23 can vary from each other, such that each of the
bottom stiffening ribs 23 has a different height, and are
preferably arranged in order of ascending or descending height. The
number, size, shape, spacing, orientation, and material of the
bottom stiffening ribs 23 can be selected such that the desired
characteristics of the ring cooling fan 10 are achieved. For
example, one or more of the bottom stiffening ribs 23 can be
disposed at an angle to the radius of the fan hub 30, and one or
more of the bottom stiffening ribs 23 can be disposed about
parallel with at least one other bottom stiffening rib 23.
Alternatively, all of the bottom stiffening ribs 23 can be disposed
in any orientation, and can be disposed in different orientations
relative to one another. Further, any number of the bottom
stiffening ribs 23 can be used. In a preferred embodiment, one or a
plurality (i.e., at least two) of such stiffening ribs 23 are used.
When a plurality of stiffening ribs 23 are used, preferably two (2)
to six (6) such stiffening ribs 23 are used, and more preferably
two (2) such stiffening ribs 23 are used.
[0029] Various other structural and material characteristics of the
stiffening ribs 20 can be selected, in conjunction with the
material and characteristics of the fan hub 30, such that undesired
warpage and bursting of the ring cooling fan 10 is substantially
impeded.
[0030] As discussed above, the ring cooling fan 10 is preferably
manufactured by an injection molding process. In such a process,
the fan hub 30 is disposed in the mold. A feed stock is mixed,
heated to a melt point, and injected at a specified pressure into
the closed mold to completely fill the mold. During the injection
process, the fan blades 40 and the fan ring 50 are molded on the
fan hub 30. At least two stiffening ribs 20 are molded on at least
one of the fan blades 40, such that the stiffening ribs 20 are
connected with each other on at most two sides, and, in a more
preferred embodiment, such that the stiffening ribs 20 are fully
connected on at most two sides (e.g., the two stiffening ribs 20
and at most two connecting sides each form full faces of the cuboid
structure, thereby forming an open-box structure that is open on
more than one full side). The filled mold enters the cooling phase
of the injection molding process, wherein the melted plastic
solidifies (i.e., changes from a liquid state to a solid state).
The mold is opened, and the ring cooling fan 10 is ejected
therefrom by one or more ejection pins. Thus, the present invention
includes a ring cooling fan 10 produced by such a process, as well
as a ring cooling fan 10 including the open-box structure produced
by a different process.
[0031] Numerous additional modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the present invention may be practiced otherwise than as
specifically described herein.
* * * * *