U.S. patent application number 14/347078 was filed with the patent office on 2014-11-20 for motorized blower assemblies, and methods of making same.
This patent application is currently assigned to MOOG Inc.. The applicant listed for this patent is Jeffrey S. Bevan, John M. Calico, Dennis R. McCoy. Invention is credited to Jeffrey S. Bevan, John M. Calico, Dennis R. McCoy.
Application Number | 20140341759 14/347078 |
Document ID | / |
Family ID | 44860495 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140341759 |
Kind Code |
A1 |
Calico; John M. ; et
al. |
November 20, 2014 |
MOTORIZED BLOWER ASSEMBLIES, AND METHODS OF MAKING SAME
Abstract
A motorized blower assembly (1) is provided for use in
respiratory therapy applications. The active motor sub-assemblies
(6, 7, 9) are encapsulated within an over-molded thermoplastic
material (5) with selected vibration-dissipative and
thermally-conductive properties. The resulting blower assembly
operates at reduced sound levels of 1.0-3.0 dB, and with an
increased efficiency of 3-9% over currently-marketed blowers of
similar size and air flow capability.
Inventors: |
Calico; John M.; (Marietta,
GA) ; Bevan; Jeffrey S.; (Murphy, NC) ; McCoy;
Dennis R.; (Murphy, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Calico; John M.
Bevan; Jeffrey S.
McCoy; Dennis R. |
Marietta
Murphy
Murphy |
GA
NC
NC |
US
US
US |
|
|
Assignee: |
MOOG Inc.
East Aurora
NY
|
Family ID: |
44860495 |
Appl. No.: |
14/347078 |
Filed: |
September 30, 2011 |
PCT Filed: |
September 30, 2011 |
PCT NO: |
PCT/US2011/001689 |
371 Date: |
June 27, 2014 |
Current U.S.
Class: |
417/349 ;
29/888.02 |
Current CPC
Class: |
F05D 2260/96 20130101;
H02K 15/14 20130101; H02K 1/185 20130101; F04D 29/668 20130101;
A61M 16/0066 20130101; H02K 5/02 20130101; H02K 15/12 20130101;
F04D 25/0606 20130101; H02K 5/1735 20130101; F04D 25/02 20130101;
F04D 29/023 20130101; F05D 2300/43 20130101; F05D 2300/5024
20130101; H02K 5/08 20130101; Y10T 29/49236 20150115; F04D 17/16
20130101; H02K 5/24 20130101 |
Class at
Publication: |
417/349 ;
29/888.02 |
International
Class: |
F04D 25/02 20060101
F04D025/02 |
Claims
1. A motorized blower assembly, comprising: a housing having an air
flow passageway extending between an inlet and an outlet; a motor
stator assembly positioned within and secured to said housing; a
bearing assembly mounted on said housing in a predetermined
position relative to said motor stator assembly; a rotor assembly
having a shaft, an impeller mounted on one marginal end portion of
said shaft, and a magnet mounted on an intermediate portion of said
shaft; wherein another marginal end portion of said shaft is
received in said bearing assembly; and an over-molded material
engaging said housing and encapsulating said motor stator
assembly.
2. A motorized blower assembly as set forth in claim 1 wherein said
over-molded material is a thermoplastic elastomer.
3. A motorized blower assembly as set forth in claim 1 wherein said
over-molded material has a predetermined coefficient of thermal
expansion.
4. A motorized blower assembly as set forth in claim 1 wherein said
over-molded material has a predetermined coefficient of thermal
conductivity.
5. A motorized blower assembly as set forth in claim 1 wherein said
over-molded material has predetermined vibration dissipative
properties to reduce the vibration generated by said blower
assembly.
6. A motorized blower assembly as set forth in claim 1 wherein said
housing includes an upper housing part and a lower housing part,
and further comprising a gasket positioned between said housing
parts.
7. A motorized blower assembly as set forth in claim 1 wherein said
motor stator assembly includes electrical terminals, and wherein
said terminals are partially encapsulated by said molded
material.
8. A motorized blower assembly as set forth in claim 1 wherein said
over-molded material is injection molded into said housing.
9. The method of manufacturing a portion of a motorized blower
assembly, comprising the steps of: providing a first die having
complementary die halves defining a first housing part cavity
therewithin; injecting a material into said first die cavity to
form a first housing part; opening said first die by moving said
first die halves apart; removing said first housing part from such
opened first die; providing a second die having complementary die
halves defining a stator assembly cavity therewithin; opening said
second die by moving said second die halves away from one another;
placing said first housing part into the cavity of one of said
second die halves; providing a stator assembly and a bearing
assembly; placing said stator assembly and said bearing assembly in
the other of said second die halves; closing said second die by
moving said second die halves toward one another to accurately
position said housing first part, said stator assembly and said
bearing assembly relative to one another, and to define a second
mold cavity therebetween; injecting a thermoplastic material into
said second mold cavity to over-mold said stator assembly and said
bearing assemblies within said first housing part; opening said
second die by moving said second mold halves away from one another;
and removing said first housing part and said over-molded stator
and bearing assemblies; thereby to manufacture a portion of a
motorized blower assembly.
10. The method as set forth in claim 9 and further comprising the
additional steps of: providing a second housing part; and joining
said second housing part to said first housing part to provide a
motorized blower assembly having an air flow passageway extending
between an inlet and an outlet.
11. The method as set forth in claim 9 wherein said first housing
part, said stator assembly and said bearing assembly are positioned
in said second mold to an accuracy of about .+-.0.0005 inches.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to: (a) improved
motorized blower assemblies (e.g., for use in respiratory therapy
for treating sleep apnea), (b) improved arrangements and assemblies
of the various blower assembly components for precise alignment and
retention when the blower assembly components are assembled, and
(c) improved methods of manufacturing such blowers.
BACKGROUND OF THE INVENTION
[0002] Sleep apnea machines contain specially-designed motors,
motor controls, and impellers that move air into, and out of, a
patient's respiratory system.
[0003] Blowers for respiratory therapy are required to be quiet due
to their proximity to the patient. Currently-marketed blowers have
sound pressure levels of approximately 42 dB. Intrinsic
structure-borne noise sources found in electric motors include
torque disturbances, bearing displacements, and magnetostriction of
ferromagnetic materials. Magnetic forces between the rotor and
stator also interact with the motor structure. Similarly, the
housing must have a sufficient stiffness to support the rotor.
However, the housing transmits forces into the motor. The inherent
acoustic sensitivity dictates the noise and vibration
characteristics of the motor. In order to reduce noise to a
minimum, potential sources of vibration between motor, rotor and
stator should be reduced or eliminated whenever possible.
[0004] A loud motor can result from intrinsically-small vibration
sources coupled with poor motor housing structural acoustic
sensitivity. Improving the acoustic sensitivity of the motor
housing through the use of vibration-dissipative materials can
reduce motor noise.
[0005] One effective vibration control strategy accommodates large
bearing displacements and results in low structural forces. One may
achieve this using a resilient bearing foundation. Negative aspects
of such a strategy include dynamic alignment, and durability
issues. For example, the rotor and stator may rub under critical
operating conditions, causing premature failure. Tolerance rings,
elastomeric O-rings, cups, sleeves and various other constructions
may be employed to provide the resilient mounting that damp
vibrations.
[0006] One relatively-recent innovation in the plastics molding
industry is the ability to over-mold various motor components.
Coils and stator assemblies have been encapsulated to protect them
from the environment, for wash-down, down-hole, and other
applications. Electric motor stator windings are also being
encapsulated with materials having relatively high coefficients of
thermal conductivity in order to improve motor performance. A wide
range of thermoplastic elastomers (TPEs) with various fillers are
being used in the over-molding process.
[0007] Blower assemblies generally include an electric motor, a
blower wheel or impeller, and a blower housing. These
sub-assemblies are generally held in operative relation to one
another by suitable mechanical means, such as screws or adhesives.
The assembly time required to handle, align, and position these
sub-assemblies, and then apply the mechanical retention, can add
significant cost to the final blower assembly.
[0008] Each of the aforementioned sub-assemblies has a dimensional
tolerance. When the components are affixed in proper relationship
to one another, the tolerances add together for a cumulative or
aggregate tolerance, known as a tolerance stack-up. This tolerance
stack-up has resulted in increased spacing between moving and
stationary parts to prevent interference and seizing. However, an
increased gap between the blower wheel or impeller and the housing
results in reduced blower efficiency. Gaps in blowers of this type
have typically been in the 0.030 inch .+-.0.018 inch range of
clearance between moving and stationary blower parts.
[0009] By molding the motor stator and bearing assemblies
simultaneously in the blower housing, part of the tolerance
stack-up between moving and stationary parts can be eliminated. The
motor stator and the bearing assembly are located in the housing
lower portion within molding die tolerances of about .+-.0.0005
inches. The housing upper portion locates off of the lower housing
portion, and the impeller is located by the bearing assembly. The
aggregate tolerance stack-up is reduced to about .+-.0.008 inches,
allowing for a nominal clearance of about 0.020 inches. Testing
confirms that a gap reduction of about 0.010 inches can produce a
power savings of about 3% by reducing the impeller speed required
to produce a particular flow. This reduced impeller speed can
result in noise reduction, and in improved life and reliability of
the blower assembly. The overall size of the blower assembly may
also be reduced, and still achieve air-handling performance
equivalent to that of a larger blower assembly.
[0010] Electric motors that operate at higher efficiencies may run
at cooler temperatures, and may have longer life and reliability
characteristics than motors that run hotter. The motors in
respiratory therapy blowers generally are insulated in a blanket of
still air. Conducting heat away from the motor would allow it to
run at a lower temperature with the benefits described.
[0011] U.S. Pat. No. 7,154,200 B2 (Neal), which is incorporated by
reference herein, describes forming the housing of a motor assembly
while encapsulating multiple motor components with a molding
material in a single step. The molding material may be selected
such that it has a coefficient of thermal expansion similar to the
coefficient of thermal expansion of the metal members of the
assembly, is thermally conductive, has vibration-damping and
shock-absorption properties, attenuates acoustic noise resulting
from magnetostriction, and encapsulates electrical terminals. The
process reduces tolerance stack-ups and assembly costs, and can
include various types of inserts and various types of bearings.
[0012] An improvement can be made over the single step of molding
the motor housing while also over-molding the motor components.
Molding a single material will require design compromises due to
the molding requirement of keeping all wall sections roughly the
same thickness. Molding the components into a preformed housing of
a different material adds functionality and flexibility to the
design. The preformed housing may have assembly-enhancing features,
such as snap hooks, tabs for screws, and the like. The material for
the housing may be selected such that it dissipates vibrations at
frequencies other than those dissipated by the molding material.
Thus, damping across a wider range of frequencies may be
achieved.
[0013] Most thermoplastic elastomers commonly used for over-molding
have similar damping characteristics for vibrations in the 0-7 kHz
frequency range. However, above 7 kHz, softer TPEs tend to damp
vibrations more effectively. Fillers, such as glasses and ceramics,
change the TPE damping characteristics and can be used to customize
the TPE for damping particular frequency ranges. By using two TPEs
with different damping characteristics, a broader and more
effective vibration damping solution can be achieved.
[0014] Additional details of known motor designs are shown and
described in U.S. Pat. No. 6,058,593 A (Siess) and U.S. Pat. No.
7,012,346 B2 (Hoffman et al.), the aggregate disclosures of which
are hereby incorporated by reference.
SUMMARY OF THE INVENTION
[0015] Motorized blower assemblies have been invented that
incorporate the best features of the current art of motor
construction, and that yet improve upon those features.
[0016] A first aspect of the invention is an improved motor with
the stator sub-assembly and the bearing sub-assembly co-located
within a matrix of thermoplastic material, which is molded into the
housing lower portion. The housing lower portion also forms the
lower portion of the blower air chamber.
[0017] The thermoplastic material has vibration-damping properties,
resulting in a quieter motor as compared with a motor constructed
without such a material.
[0018] In another aspect of the invention, an insert is over-molded
into the housing lower portion, which receives the bearing
sub-assembly in a subsequent assembly process step.
[0019] In another aspect of the invention, the housing portions are
made with features to enhance assembly of the upper blower housing
portion or other component of the final assembly. The enhanced
assembly features result in lower manufacturing costs, and the
opportunity to utilize automated manufacturing methods for further
cost reduction.
[0020] In another aspect of the invention, the thermoplastic
material also forms a gasket between the housing portions and/or
between other components of the assembly.
[0021] The molding material may be an injected-molded thermoplastic
elastomer, a potting compound, or the like. It can be a filled or
unfilled monomer or polymer. The material may be thermally
conductive to achieve a higher power rating.
[0022] In another aspect of the invention, affixing the
sub-assemblies within the lower blower housing by means of the
over-molded material results in a lower manufacturing cost and
reduced tolerance stack-up as compared with other means of affixing
the sub-assemblies.
[0023] In another aspect of the invention, the housing lower
portion forms an exit for the terminals of the stator assembly, and
a pocket to receive an external connector.
[0024] In still another aspect of the invention, the upper and
lower housing portions, and the shaft, have features to enhance
automated handling and assembly. With parenthetical reference to
the corresponding parts, portions or surfaces of the disclosed
embodiments, merely for purposes of illustration and not by way of
limitation, the present invention broadly provides, in one aspect,
an improved motorized blower assembly (1) for use in respiratory
therapy. The improved blower assembly broadly includes: a housing
(2, 3) having an air flow passageway extending between an inlet
(11) and an outlet (12); a stator assembly (6) positioned within
and secured to the housing; a bearing assembly (9) mounted on the
housing in a predetermined position relative to the stator
assembly; a rotor assembly having a shaft (8), an impeller (10)
mounted on one marginal end portion of the shaft, and a magnet (7)
mounted on an intermediate portion of the shaft; wherein another
marginal end portion of the shaft is received in the bearing
assembly; and an over-molded material (5) engaging said housing and
encapsulating the motor stator assembly.
[0025] The molding material may be a thermoplastic elastomer, or a
potting compound which is applied via potting methods.
[0026] The molding material may have a predetermined coefficient of
thermal expansion and/or a predetermined coefficient of thermal
conductivity.
[0027] The molding material may be selected to have predetermined
vibration-dissipative properties resulting in quieter blower
operation.
[0028] The components may have design features to enhance automated
assembly and reduce assembly costs.
[0029] The over-molded components and assemblies may have reduced
tolerance stack-ups resulting in more efficient and quieter
operation of the blower.
[0030] A gasket may be molded onto one of the housings to create a
seal between housings, resulting in more efficient and quieter
operation of the blower.
[0031] In another aspect, the invention provides an improved method
of manufacturing a portion of a motorized blower assembly,
comprising the steps of: providing a first die having complementary
die halves (13, 14) defining a first housing part cavity
therewithin; injecting a material into said first die cavity to
form a first housing part (3); opening the first die by moving said
first die halves apart; removing said first housing part (3) from
such opened first die; providing a second die having complementary
die halves (15, 16) defining a stator assembly cavity therewithin;
opening the said second die by moving the second die halves away
from one another; placing said first housing part (3) into the
cavity of one (15) of said second die halves; providing a stator
assembly (6) and a bearing assembly (9); placing the stator
assembly and the bearing assembly in the other (16) of the second
die halves; closing said second die by moving said second die
halves toward one another to accurately position said housing first
part, said stator assembly and said bearing assembly relative to
one another, and to define a second mold cavity therebetween;
injecting a thermoplastic material (5) into the second mold cavity
to over-mold the stator assembly and the bearing assembly within
said first housing part; opening said second die by moving said
second mold halves away from one another; and removing said first
housing part and said over-molded stator and bearing assemblies;
thereby to manufacture a portion of a motorized blower assembly
(1).
[0032] Accordingly, the general object of the invention is to
provide improved motorized blower assemblies.
[0033] Another object is to provide improved methods and apparatae
for arranging and assembling the various blower assembly components
for precise alignment and retention when the blower assembly
components are assembled together.
[0034] Still another object is to provide an improved method of
producing a low-cost, high performance, quiet motorized blower
assembly.
[0035] These and other objects and advantages will become apparent
from the foregoing and ongoing written specification, the drawings,
and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a fragmentary longitudinal vertical sectional view
of a first form of an improved blower assembly.
[0037] FIG. 2 is a top plan view of the blower assembly shown in
FIG. 1, with a portion cutaway to illustrate details of the
impeller.
[0038] FIG. 3 is a schematic view of the housing lower portion
molded within the first mold.
[0039] FIG. 4 is schematic view, showing the first mold halves
having been moved apart so that the molded housing lower portion
can be removed.
[0040] FIG. 5 is a schematic view of an opened second mold, this
view showing the molded housing lower portion as having been
positioned within the a second mold upper half, with the stator
assembly and the bearing assembly being positioned on the second
mold lower half.
[0041] FIG. 6 is a schematic view similar to FIG. 5, but showing
the second mold halves as having been moved together to close the
second mold and to position the stator and bearing assemblies
relative to the housing lower portion.
[0042] FIG. 7 is a schematic view showing a thermoplastic elastomer
as having been injected into the second mold cavity to over-mold
the stator and bearing assemblies within the housing lower
portion.
[0043] FIG. 8 is a schematic view similar to FIG. 7, but showing
the second mold halves as having been moved away from one another
to open the second mold, and to allow the over-molded portion of
the blower assembly to be removed from the second mold.
[0044] FIG. 9 is an enlarged fragmentary longitudinal vertical
sectional view showing the rotor assembly as having been inserted
into the bearing assembly.
[0045] FIG. 10 is a side elevation showing the housing upper
portion as having been mounted on the housing lower portion, with a
portion cutaway to show portions of the two housing portions in
cross-section.
[0046] FIG. 11 is an exploded side elevation of a second form of
the improved motorized blower assembly.
[0047] FIG. 12 is an enlarged fragmentary longitudinal vertical
sectional view of a third form of the improved motorized blower
assembly.
DESCRIPTION OF THE INVENTION
[0048] At the outset, it should be clearly understood that like
reference numerals are intended to identify the same structural
elements, portions or surfaces consistently throughout the several
drawing figures, as such elements, portions or surfaces may be
further described or explained by the entire written specification,
of which this detailed description is an integral part. Unless
otherwise indicated, the drawings are intended to be read (e.g.,
cross-hatching, arrangement of parts, proportion, degree, etc.)
together with the specification, and are to be considered a portion
of the entire written description of this invention. As used in the
following description, the terms "horizontal", "vertical", "left",
"right", "up" and "down", as well as adjectival and adverbial
derivatives thereof (e.g., "horizontally", "rightwardly",
"upwardly", etc.), simply refer to the orientation of the
illustrated structure as the particular drawing figure faces the
reader. Similarly, the terms "inwardly" and "outwardly" generally
refer to the orientation of a surface relative to its axis of
elongation, or axis of rotation, as appropriate.
[0049] Referring now to the drawings, and, more particularly, to
FIG. 1 thereof, a first embodiment of an improved motorized blower
assembly according to the invention is designated generally
indicated at 1, and broadly includes a housing lower portion 3, a
housing upper portion 2, a gasket 4 located between the two housing
portions, a wound stator assembly 6, a permanent magnet 7, a shaft
8, a bearing assembly 9, an overmolded thermoplastic elastomeric
material 5, and an impeller 10.
[0050] The stator assembly 6 is first constructed using steel
laminations, which are aligned and stacked to form a
magnetically-inducible core having a plurality of poles, about
which windings made up of insulated electrically-conductive wire
are wound or placed. The art of forming poles and windings of
various configurations to create magnetic poles is well known, and
therefore need not be discussed further herein.
[0051] The rotor sub-assembly is constructed by either over-molding
the magnet 7 onto the shaft 8, or by using adhesive to affix the
magnet 7 onto the shaft 8. The magnet 7 can be magnetized with any
number of desired poles, either before or after assembly to the
shaft. The impeller 10 is either molded onto the shaft 8, or is
molded separately and affixed to the shaft 8 by pressing on, by
using an adhesive, or by some other suitable means. The assembly
order is optional.
[0052] In operation, the rotor sub-assembly consisting of the
impeller 10, the shaft 8, and the magnet 7, is caused to rotate due
to tangential forces created between the stator 6 and the magnet 7
when electric current is caused to flow in the windings of the
stator 6.
[0053] Referring now to FIG. 2, the rotating impeller 10 causes a
pressure differential between the blower inlet 11 and the blower
outlet 12, which produces the desired air flow.
[0054] Referring now to FIG. 3, the blower housing lower portion 3
is formed by means of injecting plastic into a cavity formed
between mold die halves 13, 14. In FIG. 4, the die is shown as
having been opened, and the lower housing portion 3 is shown as
being separated, prior to removal.
[0055] FIG. 5 shows the housing lower portion 3 as having been
placed into a separate upper die half 15, which is like die half 14
but located in a different molding machine. Lower die half 16 is
introduced, which has the stator assembly 6 and bearing assembly 9
pre-loaded and positively located in axial and radial relationship
to each other.
[0056] In FIG. 6, the die halves 15 and 16 are shown as having been
closed, which positively locates the stator assembly 6 and bearing
assembly 9 in axial and radial relationship with the lower housing
portion 3 within die tolerances. The molding die has tolerances of
about .+-.0.0002 inch on diameters and axial lengths. The lower
housing portion locates within the die half within about .+-.0.003
inch. The axial and radial tolerance stack-up between bearing
assembly and stator assembly is about .+-.0.0004 inch. The axial
and radial tolerance stack-up between each of them and the housing
is about .+-.0.0032 inch.
[0057] In FIG. 7, the thermoplastic elastomer 5 is shown as having
been injected into the mold, which locks the stator assembly 6 and
bearing assembly 9 in place in the housing lower portion 3. A
potting material or epoxy may alternatively be used to fill the
cavity in the mold.
[0058] In FIG. 8, the two die halves 15, 16 are shown as having
been separated, and the resulting assembly is shown as having been
removed.
[0059] In FIG. 9, the pre-assembled rotor assembly 17 is affixed to
the molded assembly 18 by press fitting the shaft 8 into the
bearing assembly 9. Alternatively, the shaft 8 can be affixed to
the bearing assembly 9 by a suitable adhesive or some other
means.
[0060] FIG. 10 shows the upper housing portion 2 as being affixed
to the lower housing portion 3 by means of snaps, severally
indicated at 20. The pre-formed gasket 4 between the upper and
lower housing portions 2, 3 prevents air leaks for higher blower
efficiency, and results in quieter operation. Alternatively, the
upper and lower housing portions 2, 3 can be held together by means
of screws, clamps, an adhesive, or some other means. The three
terminals 21 are secured by the molding material 5, and are
designed and located so as to receive a mating electrical
connector.
[0061] In FIG. 1, the motor design (i.e., the orientation of stator
assembly 6 and magnet 7) has a radial orientation, with the rotor
being within the stator member 6. The invention can also be
practiced with a motor design in an axial orientation. The
invention can also be practiced with a motor design with radial
orientation with the rotating member on the outside of the
stationary member.
[0062] In FIG. 1, the motor is a brushless DC motor. Such a motor
may be run with feedback devices (e.g., Hall Effect devices,
resolvers, encoders, or some other means), or it may be run without
feedback in a sensorless drive scheme. The invention could also be
practiced with other motor types, such as a brushless AC motor, a
permanent magnet DC motor, an induction motor, a stepper motor, a
switched reluctance motor, or some other motor type.
[0063] In FIG. 1, a bearing assembly 9 is a type of cartridge with
two rows of preloaded balls is molded into the housing lower
portion 3. The bearing pre-load is established in the construction
of the bearing cartridge by the bearing vendor. The invention can
also be practiced by mounting two separate bearings onto the shaft,
either next to each other as a duplex pair, or, separated by some
distance along the shaft. The invention can also be practiced as
depicted in FIG. 11 by mounting the bearing assemblies 9 onto the
shaft 8 and pressing or bonding the bearing assemblies into a
receiving sleeve 19 that has been molded into the lower housing
assembly 3. The invention may also be practiced by assembling the
bearing cartridge between the magnet and the impeller thus reducing
the over-hanging mass. The invention may also be practiced using a
sleeve bearing, magnetic bearing, hydrodynamic bearing, or some
other type of bearing system.
[0064] In the preferred embodiment of FIG. 1, the molding material
5 may be selected so that it has a coefficient of linear thermal
expansion similar to that of the plastic components or the metal
components of the assembly such as the shaft 8. The molding
material 5 may also be selected so that it has an increased thermal
conductivity, which may be isotropic or directional based on the
needs of a particular application. The molding material 5 may also
be selected for desired vibration damping properties that are tuned
to specific frequencies or frequency ranges. The molding material 5
may be an injected molded thermoplastic elastomer, a potting
compound, or the like.
[0065] Referring to FIGS. 4-5, an alternate process to removing the
housing lower portion 3 from die half 14 and replacing it with
similar die half 15, is to retain the housing lower portion 3 in
die half 14 thereby requiring a two-shot molding operation.
[0066] Referring to FIG. 12, an alternate construction is shown
whereby the stator and bearing assemblies are replaced with a
completed motor assembly 22 which has been over-molded into the
lower blower housing 3. With this embodiment of the invention, the
impeller would be pressed onto the shaft 8 of the motor 22 after
the overmolding process is completed. The improvements of the
invention are not compromised by this alternate construction.
[0067] Final assembly of the housing upper and lower portions may
be accomplished by the use of screws, snaps, welding, bonding, or
some other means, as commonly practiced.
[0068] The invention thus far described has incorporated a single
impeller to produce air movement in the motorized blower assembly.
Other embodiments of the invention include fan and blower wheels,
as well as multiple stages of the air mover.
[0069] Therefore, the invention broadly provides: (a) improved
motorized blower assemblies (e.g., for use in respiratory therapy
for treating sleep apnea), (b) improved arrangements and assemblies
of the various blower assembly components for precise alignment and
retention when the blower assembly components are assembled, and
(c) improved methods of manufacturing such blowers.
MODIFICATIONS
[0070] The present invention contemplates that many changes and
modifications may be made.
[0071] For example, the housing may have different shapes,
dimensions and/or proportions. The motor may be of different types,
constructions and shapes. The assembly sequences may be changed or
modified. The type of blower may also be changed.
[0072] Therefore, while several preferred embodiments of the
improved motorized blower assembly have been shown and described,
and several modifications thereof discussed, persons skilled in
this art will readily appreciate that various additional changes
and modifications may be made without departing from the spirit of
the invention, as defined and differentiated by the following
claims.
* * * * *