U.S. patent application number 11/754454 was filed with the patent office on 2008-12-04 for dynamically balanced molded blade assemblies for blowers and fans.
Invention is credited to George Grigorow, James D. Mercer, Raymond L. Norbury, JR..
Application Number | 20080298966 11/754454 |
Document ID | / |
Family ID | 40088437 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080298966 |
Kind Code |
A1 |
Grigorow; George ; et
al. |
December 4, 2008 |
DYNAMICALLY BALANCED MOLDED BLADE ASSEMBLIES FOR BLOWERS AND
FANS
Abstract
Dynamically balanced molded blade assemblies may be formed. A
face plate of a dynamically balanced molded blade assembly may have
one or more openings and/or one or more protrusions so that the
blade assembly is within acceptable balance tolerance when rotated
by a motor shaft of a fluid moving device.
Inventors: |
Grigorow; George; (Bristol,
TX) ; Mercer; James D.; (Howe, TX) ; Norbury,
JR.; Raymond L.; (Dallas, TX) |
Correspondence
Address: |
MEYERTONS, HOOD, KIVLIN, KOWERT & GOETZEL, P.C.
P.O. BOX 398
AUSTIN
TX
78767-0398
US
|
Family ID: |
40088437 |
Appl. No.: |
11/754454 |
Filed: |
May 29, 2007 |
Current U.S.
Class: |
416/144 |
Current CPC
Class: |
F01D 5/26 20130101; F05D
2260/34 20130101 |
Class at
Publication: |
416/144 |
International
Class: |
F01D 5/26 20060101
F01D005/26 |
Claims
1. A molded blade assembly, comprising: a plurality of blades; a
face plate coupled to the plurality of blades, wherein the face
plate comprises: a hub with a shaft bore configured to couple the
blade assembly to a shaft of a motor; and balancing means
configured to dynamically balance the blade assembly within
acceptable balance tolerance when the blade assembly is rotated by
the shaft of the motor during use.
2. The molded blade assembly of claim 1, wherein the balancing
means comprises one or more openings formed in the face plate.
3. The molded blade assembly of claim 1, wherein the balancing
means comprises a plurality of openings formed in the face plate,
and wherein at least one of the openings comprises an opening
completely through the face plate.
4. The molded blade assembly of claim 1, wherein the balancing
means comprises a plurality of openings formed in the face plate,
and wherein the openings are evenly spaced angularly about a center
of the face plate or irregularly spaced angularly about the center
of the face plate.
5. The molded blade assembly of claim 1, wherein the balancing
means comprises a plurality of openings formed in the face plate,
and wherein at least one of the openings has a different size than
at least one other opening.
6. The molded blade assembly of claim 1, wherein the balancing
means comprises at least one blind opening formed in the face
plate.
7. The molded blade assembly of claim 1, wherein the balancing
means comprises one or more protrusions extending from the face
plate.
8. The molded blade assembly of claim 1, wherein the balancing
means comprises at least one protrusion extending from the face
plate, and at least one opening formed in the face plate.
9. A fluid moving device, comprising: a motor having a shaft; a
molded blade assembly coupled to the shaft, wherein the blade
assembly comprises a hub with a shaft opening, a face plate, and a
plurality of blades; and wherein the face plate includes balancing
means for dynamically balancing the blade assembly within
acceptable balance tolerance when the blade assembly is rotated at
operating speed by the shaft.
10. The fluid moving device of claim 9, wherein the fluid moving
device is a blower.
11. The fluid moving device of claim 9, wherein the fluid moving
device is a fan.
12. The fluid moving device of claim 9, wherein the balancing means
comprises one or more openings formed in the face plate.
13. The fluid moving device of claim 9, wherein the balancing means
comprises a plurality of openings formed in the face plate, and
wherein at least one of the openings comprises an opening
completely through the face plate.
14. The fluid moving device of claim 9, wherein the balancing means
comprises a plurality of openings formed in the face plate, and
wherein the openings are evenly spaced angularly about a center of
the face plate or irregularly spaced angularly about the center of
the face plate.
15. The fluid moving device of claim 9, wherein the balancing means
comprises a plurality of openings formed in the face plate, and
wherein at least one of the openings has a different size than at
least one other opening.
16. The fluid moving device of claim 9, wherein the balancing means
comprises at least one blind opening formed in the face plate.
17. The fluid moving device of claim 9, wherein the balancing means
comprises one or more protrusions extending from the face
plate.
18. The fluid moving device of claim 9, wherein the balancing means
comprises at least one protrusion extending from the face plate,
and at least one opening formed in the face plate.
19. A method of producing dynamically balanced molded blade
assemblies, comprising: forming a first blade assembly using a
mold; coupling the first blade assembly to a test machine;
operating the test machine to determine the balance characteristics
of the first blade assembly at a working rotational speed;
assessing a location of one or more balancing means to be
incorporated in a face plate of the first blade assembly to result
in a dynamically balanced first blade assembly; and adjusting the
mold to form the balancing means in the face plate of a blade
assembly produced by the mold; and using the mold to form one or
more dynamically balanced blade assemblies.
20. The method of claim 19, wherein the balancing means comprises
at least one opening formed in a face plate of a blade assembly
produced by the mold.
21. The method of claim 19, wherein the balancing means comprises
at least one protrusion formed as part of the face plate of a blade
assembly produced by the mold.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to fluid moving devices such
as blowers, fans, and propellers. More particularly, the invention
relates to providing openings in face plates of molded blade
assemblies of the fluid moving devices so that the blade assemblies
are dynamically in balance when rotated by the motor of the fluid
moving devices during use.
[0003] 2. Description of Related Art
[0004] Fluid moving devices may be used to move fluid in a desired
direction. For example, fluid moving devices may be used to move
air in air conditioning system to move air from air inlets, past
one or more heat exchangers, and through air vents. Fluid moving
devices include blowers and fans. The blade assemblies of the fluid
moving devices move the gas. The blower wheels of blowers and fan
blades of fans are blade assemblies. Blade assemblies typically
include a plurality of blades around a circular face plate. A shaft
of a motor may be coupled to a hub of the face plate. The motor
turns the shaft and the blade assemblies create desired flow (e.g.,
air flow). Having balanced blade assemblies may inhibit vibrations,
noise, and wear on bearings and other parts of the motor. Blade
assemblies may be made of polymeric materials so the blade
assemblies are light, easy to produce, and relatively inexpensive.
Blade assemblies may be made using injection molding processes or
other formation processes.
[0005] One way to make balanced blade assemblies is to subject the
blade assembly to a balancing process after the blade assembly is
produced. For example, the blade assembly may be coupled to a
balancing machine and spun to determine where to apply one or more
exterior balancing clip-on weights. A weight or weights are added
on the light side of the blade assembly to counter the weight of
the heavier side. Some blade assemblies are formed with excess
material at select locations. Some of the excess material may be
cut or otherwise removed from the heavier side to bring the blade
assembly into balance when the blade assembly is rotated.
[0006] U.S. Pat. No. 7,063,507 to Hsieh, which is incorporated
herein by reference, describes a process of forming a balance
adjusted fan by inserting balance weights in openings in the hub of
the blade assembly. U.S. Pat. No. 5,547,365 to Chuang, which is
incorporated herein by reference, describes a method of balancing a
fan blades with an integrally formed shaft by shifting the position
of a reference line used when coupling a magnetic ring to the blade
assembly and/or by adjusting the length of one or more knock out
pins to change the depth of dents made in the blade assembly by the
knock out pins when the blade assembly is ejected from the mold.
The mold includes a knock out pin for each blade of the blade
assembly. U.S. Pat. No. 5,927,947 to Botros, which is incorporated
herein by reference, describes a balanced blower wheel that is made
by a mold with an adjustable portion that controls the thickness of
a portion of the inlet ring of the blade assembly. The thickness of
the portion of the inlet ring is controlled to produce balanced
blade assemblies.
[0007] Other methods to produce balanced blade assemblies may also
be used. Another method for producing balanced blade assemblies
includes cutting selected perimeter ejector pins of the mold so
that the mold produces pegs in the resulting blade assemblies that
act as counter weights. Another method of producing balanced blade
assemblies involves removing metal from the mold from one or more
locations to increase the amount of polymer at the one or more
locations. The excess polymer may be a counter weight that balances
the resulting blade assembly. Another method of balancing the
blower wheel during blade assembly formation involves adjusting one
or more set screws that control polymer flow into the mold. The set
screws are typically located at fixed positions such that the
thickness of a portion of the blade assembly that changes due to
adjustment of the set screw is in a vertical plane in an axial
direction relative to the rotational axis of the blade assembly.
Such methods may require tremendous amounts of trial and error and
may require periodic testing of the blade assemblies to ensure that
the produced blade assemblies are balanced.
[0008] Blade assemblies that are light weight, relatively
inexpensive to produce, and balanced are needed. The blade
assemblies may be components of fluid moving devices. The blade
assemblies may be dynamically balanced when rotating within
acceptable balance tolerance required by the industry in which the
blade assemblies are used.
SUMMARY
[0009] Some embodiments described herein are related to molded
blade assemblies. The blade assemblies may be components of fluid
moving devices. The blade assemblies may include a plurality of
blades coupled to face plates. The face plates may include hubs and
balancing means. The hubs may have shaft bores that allow the blade
assemblies to be coupled to motor shafts of the fluid moving
devices. The balancing means dynamically balances the blade
assemblies within acceptable balance tolerance when the blade
assemblies are rotated by the motor shafts.
[0010] In some embodiments, the balancing means of the blade
assemblies are openings formed in the face plates of the blade
assemblies. The openings may be through openings and/or blind
openings. If the blade assembly includes more than one opening, the
openings may be symmetrically arranged about a center of the face
plate. If the blade assembly includes more than one opening, at
least one of the openings may have a different size than other
openings. In some embodiments, the balancing means of the blade
assemblies are protrusions extending from the face plate. In some
embodiments, the balancing means of the blade assemblies includes
openings and protrusions.
[0011] Some embodiments described herein are related to fluid
moving devices. The fluid moving devices include motors with
shafts. A molded blade assembly may be coupled to the shaft of the
motor. The molded blade assembly may include a hub with a shaft
opening, a face plate, and a plurality of blades. The face plate
includes balancing means for dynamically balancing the blade
assembly within acceptable balance tolerance when the blade
assembly is rotated at operating speed by the shaft. The balancing
means may comprise one or more openings formed in the face plate
and/or one or more protrusions extending from the face plate. The
fluid moving devices may be blowers, fans, or other fluid
movers.
[0012] In some embodiments, methods may be used to produce
dynamically balanced molded blade assemblies. The method may
include forming a first blade assembly using a mold. The first
blade assembly may be coupled to a test machine. The test machine
may be operated to determine the balance characteristics of the
first blade assembly at a working rotational speed. The results may
be used to assess a location of one or more balancing means to be
incorporated in a face plate of the first blade assembly to result
in a dynamically balanced first blade assembly. The mold may be
adjusted to form the balancing means in the face plate of a blade
assembly produced by the mold. The mold may be used to from one or
more dynamically balanced molded blade assemblies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Features and advantages of the methods and apparatus of the
present invention will be more fully appreciated by reference to
the following detailed description of presently preferred but
nonetheless illustrative embodiments in accordance with the present
invention when taken in conjunction with the accompanying drawings
in which:
[0014] FIG. 1 depicts a perspective view of an embodiment of a
blower.
[0015] FIG. 2 depicts a perspective view of an embodiment of a
fan.
[0016] FIG. 3 depicts a perspective of an embodiment of a
motor.
[0017] FIG. 4 depicts a perspective view of the shaft of the
motor.
[0018] FIG. 5 depicts a perspective view of an embodiment of a
single gas inlet blade assembly for a blower.
[0019] FIG. 6 depicts a side view of the single gas inlet blade
assembly depicted in FIG. 5.
[0020] FIG. 7 depicts a perspective view of an embodiment of a
double gas inlet blade assembly for a blower.
[0021] FIG. 8 depicts a side view of the double gas inlet blade
assembly depicted in FIG. 7.
[0022] FIG. 9 depicts a side view of the blade assembly depicted in
FIG. 2.
[0023] FIG. 10 depicts a perspective view of an embodiment of a
blade assembly with a protrusion formed on the face plate of the
blade assembly.
[0024] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof are shown by
way of example in the drawings and will herein be described in
detail. The drawings may not be to scale. It should be understood
that the drawings and detailed description thereto are not intended
to limit the invention to the particular form disclosed, but to the
contrary, the intention is to cover all modifications, equivalents
and alternatives falling within the spirit and scope of the present
invention as defined by the appended claims.
DETAILED DESCRIPTION OF EMBODIMENTS
[0025] A fluid moving device may be used in a system to direct the
flow of a fluid in a desired direction or directions at a desired
rate. A fluid moving device may include a motor with a shaft, and a
blade assembly that is coupled to the shaft of the motor. The motor
rotates the shaft to rotate the blade assembly. The blade assembly
moves the fluid. The fluid may be gas (e.g., air), liquid (e.g.,
water), a powder (e.g., flour), and/or combinations thereof.
Examples of fluid moving devices that move gas are blowers and
fans. Examples of fluid moving devices that move liquid and/or
solids are propellers and mixers.
[0026] The blade assembly of the fluid moving device needs to be
within an acceptable balance tolerance. If the blade assembly is
not within the acceptable balance tolerance the fluid moving device
may have too much vibration, make too much noise, and/or the life
of the motor may be shortened.
[0027] Blade assemblies may be made using an injection molding
process. The blade assembly may be made from a single type of
polymer, or from a blend of polymers. The polymer may include one
or more additives, stabilizing compounds, and/or strengthening
materials (e.g., glass fibers).
[0028] A number of factors may influence the balance of the blade
assembly of a fluid moving device. These factors may include: 1)
the operating rotation speed of the blade assembly, 2) the size of
the blade assembly, 3) the location of mass due to the location of
gates in the mold used to form the blade assembly and due to flow
characteristics of the mold design and process, and 4) unbalance
due to the motor shaft. Many shafts of motors used to rotate blade
assemblies include a flat portion or "D" profile that facilitates
coupling the blade assembly to the shaft. The "D" profile allows an
interference fit to be formed between the shaft and the blade
assembly to inhibit slippage of the blade assembly on the shaft of
the motor. In some embodiments, a fastener or fasteners secure the
blade assembly to the shaft. The material removed from the shaft to
form the "D" profile may contribute to unbalance of the blade
assembly coupled to the shaft when the shaft rotates.
[0029] To bring or make rotating blade assemblies within acceptable
balance tolerance, some material of the face plates of the blade
assemblies may be removed. The face plate of the blade assembly may
be an area of the blade assembly where removal of material will
have the least adverse affect on the strength of the blade
assembly. Molding blade assemblies with material removed from the
face plates to balance the blade assemblies allows for cost savings
due to less material used when the blade assembly is made and/or
due to elimination of secondary balancing labor costs. In some
embodiments, the openings in the face plate may be formed after the
blade assembly is molded. For example, openings in the face plate
may be drilled, punched, cut or otherwise formed after the blade
assembly is formed. In some embodiments, one or more scoring marks
may be formed in the face plate that allow material to be punched
out of the face plate to make openings in the face plate after the
blade assembly is formed.
[0030] The opening or openings formed in the face plate may be
formed completely through the face plate or only partially through
the face plate (e.g., blind openings). In some embodiments, some
openings may be through openings while others are blind openings.
The openings may have any desired shape, such as, but not limited
to circular, arced, oval, elliptical, rectangular, polygonal and/or
irregularly shaped.
[0031] If more than one opening is formed in the face plate, the
openings may have different sizes. Having various sized openings
spaced around the face plate may provide a relatively simple way to
compensate for the missing or removed material mass in the "D"
profile of motor shaft. In some embodiments, the openings may be
spaced in a regular angular pattern around the face plate. For
example, six openings may be formed in the face plate around the
face plate with the center of each opening being at about a
60.degree. angle relative to the center of the next opening and
relative to the center of the face plate. In some embodiments, the
openings may be angularly spaced in an irregular pattern.
[0032] In some embodiments, the radial distance to the center of
the openings from a center of the face plate is substantially the
same for all of the openings in the face plate. In other
embodiments, the distance from the center of the face plate to the
center of one or more of the openings in the face plate may be
different than the radial distance from the center of the face
plate to the center of another opening in the face plate. In some
embodiments, two or more sets of openings may be formed at
different radial distances from the center of the face plate. For
example, a first set of three circular openings may be formed at a
radial distance of about 1 inch from the center of the face plate,
the three openings being spaced 120.degree. apart. A second set of
four arced openings may be formed at a radial distance of about 1.5
inches from the center of the face plate, the four openings being
spaced 90.degree. apart from each other.
[0033] In some embodiments, the position of the opening or the
openings in the face plate may be influenced by the size of the
blade assembly and/or by the rotation speed of the blade assembly.
The radial distance of the opening or openings from the center of
the face plate may increase as the size of the blade assembly
and/or the operating speed of the blade assembly increases.
[0034] FIG. 1 and FIG. 2 depict embodiments of fluid moving devices
50. FIG. 1 depicts an embodiment where fluid moving device 50 is a
blower. Fluid moving device 50 may include housing 52, motor 54,
and blade assembly 56. Fasteners known and commonly used in the art
may be used to hold sections of housing 52 together and to secure
motor 54 to the housing. If the fluid moving device is a blower,
the blade assembly is a blower wheel. In some embodiments, a shaft
may exit each end of the motor. A blade assembly may be coupled to
each shaft to form a dual blower wheel blower.
[0035] FIG. 2 depicts an embodiment where fluid moving device 50 is
a fan. Fluid moving device 50 may include motor 54, and blade
assembly 56. In some embodiments, blade assembly 56 and/or motor 54
may be placed in a frame or cage. If the fluid moving device is a
fan, the blade assembly is the fan blade.
[0036] FIG. 3 depicts an embodiment of motor 54 that may be used to
rotate the blade assembly of a fluid moving device. Motor 54 may
include body 60 and shaft 62. Motor 54 may be electrically coupled
to a power source. The power source provides electricity to motor
54 to rotate shaft 62. FIG. 4 depicts a detail representation of
shaft 62. Shaft 62 may include flat 64. Flat 64 facilitates
coupling of the blade assembly to the motor.
[0037] FIGS. 5-8 depict embodiments of blade assemblies 56 for
blowers. As known in the art, a blade assembly may have a forward
incline blade design or a backward incline blade design. FIG. 2 and
FIG. 9 depict an embodiment of blade assembly 56 for a fan. Blade
assemblies 56 may include blades 66 and face plate 68. Face plate
68 may include hub 70, ribs 72, and one or more openings 74. In
some embodiments, rims 76 support the ends of blades 66. Hub 70 may
be used to couple blade assembly 56 to the motor shaft. Hub 70 may
include a shaft bore. Ribs 72 may add rigidity to face plate 68 and
strengthen blade assembly 56. Opening or openings 74 may reduce the
weight of blade assembly 56 in one or more locations so that the
blade assembly is balanced within acceptable tolerance when mounted
to the shaft of the motor and rotated.
[0038] FIG. 5 and FIG. 6 depict an embodiment of blade assembly 56
for a single gas inlet blower. FIG. 1 depicts blade assembly 56
used to form the single gas inlet blower with a forward incline
blade design. Gas enters fluid moving device 50 through inlet 78
and exits the fluid moving device through outlet 80. As shown in
FIG. 5 and FIG. 6, openings 74 may be formed in face plate 68.
Openings 74 may balance blade assembly 56 so that the blade
assembly is balanced within acceptable tolerance when rotated by
the motor of the fluid moving device. Opening 74' may be smaller
than other openings 74.
[0039] FIG. 7 and FIG. 8 depict an embodiment of blade assembly 56
for a double gas inlet blower. When blade assembly 56 is coupled to
the shaft of the motor of the fluid moving device, the housing of
the fluid moving device has two inlets to allow gas to be drawn
into the blade assembly on each side of face plate 68. Openings 74
may be formed in face plate 68 so that blade assembly is balanced
within acceptable tolerance when rotated by the motor of the fluid
moving device. Openings 74'' may be blind openings that do not
extend through face plate 68. One or more openings may be smaller
than other openings.
[0040] FIG. 9 depicts an embodiment of blade assembly 56 of a fan.
FIG. 2 depicts blade assembly 56 coupled to shaft 62 of motor 54.
Openings may be formed in face plate 68. One or more of the
openings may be blind openings. Opening size and depth may depend
on strength considerations and balance considerations so that the
blade assembly is balanced within acceptable tolerance on a
rotating motor shaft.
[0041] In some embodiments, the blade assembly may be formed with
one or more protrusions from the face plate that add weight to the
blade assembly so that the blade assembly is dynamically balanced
when rotating. The protrusions may have any desired shape, such as,
but not limited to, block shaped, cylindrical, domed, or
irregularly shaped. In some embodiments, only protrusions are used
to produce dynamically balanced blade assemblies. Different sizes
and/or different protrusion lengths may be formed on the face plate
of the blade assembly. In some embodiments, protrusions are used in
conjunction with openings to produce dynamically balanced blade
assemblies. FIG. 10 depicts an example of blade assembly 56 that
includes protrusion 82 and openings 74 in face plate 68. Protrusion
82 may be formed as part of face plate 68 near a flat portion of
hub 70. Protrusion 82 may add extra weight to blade assembly 56 to
counteract missing weight mass of the shaft due to the flat portion
formed in the shaft (i.e., flat 64 depicted in FIG. 4).
[0042] A mold may be formed to make the blade assembly without
openings formed in the face plate of the blade assembly. One or
more blade assemblies may be molded using the mold to form blade
assemblies without openings in the face plate. At least one of the
blade assemblies may be coupled to a balancing device. The
balancing device may have a motor shaft that is substantially the
same as the motor shafts to which the balanced blade assemblies
formed by the mold are to be coupled. The blade assembly without
openings in the face plate may be coupled to the shaft of the
balancing device in the same manner that the balanced blade
assemblies are to be coupled to the motor shafts. The balancing
device may be activated to rotate the shaft to the same operating
speed at which the shafts of the motors will run. The balancing
device may be used to determine where the blade assembly without
openings is out of balance at the operating test speed.
[0043] Rotation may be stopped. Based on information provided from
the balancing device, one or more openings may be formed in the
face plate of the blade assembly so that the blade assembly will
come within acceptable balanced tolerances. In some embodiments,
one or more weights are attached to the face plate or to one or
more blades. The blade assembly may be rotated on the balancing
device to the operating test speed to determine if the blade
assembly is in balance within acceptable tolerance. If the blade
assembly is not in balance, additional openings in the face plate
may be formed or existing openings in the face plate may be
enlarged so that the blade assembly is in balance when rotated at
the operating speed. If an error is made and too much material from
the face plate is removed, the process can be restarted with a new
blade assembly that has no openings formed in the face place. If
the blade assembly is balanced within acceptable tolerances, the
mold may be adjusted. The adjusted mold may include obstructions
placed in portions of the mold so that blade assemblies formed by
the mold include openings in the face plate at desired locations
and/or openings may be formed in the mold so that blade assemblies
formed by the mold include protrusions extending from the face
plate at desired locations.
[0044] One or more blade assemblies may be made with the adjusted
mold. One or more of the blade assemblies made from the adjusted
mold may be tested on the balance device to ensure that blade
assemblies made using the mold are within acceptable balance
tolerance. If needed, the mold may be further adjusted to produce
blade assemblies that are within acceptable balance tolerance when
rotated on a motor shaft.
[0045] Further modifications and alternative embodiments of various
aspects of the invention will be apparent to those skilled in the
art in view of this description. Accordingly, this description is
to be construed as illustrative only and is for the purpose of
teaching those skilled in the art the general manner of carrying
out the invention. It is to be understood that the forms of the
invention shown and described herein are to be taken as the
presently preferred embodiments. Elements and materials may be
substituted for those illustrated and described herein, parts and
processes may be reversed, and certain features of the invention
may be utilized independently, all as would be apparent to one
skilled in the art after having the benefit of this description of
the invention. Changes may be made in the elements described herein
without departing from the spirit and scope of the invention as
described in the following claims.
* * * * *