U.S. patent application number 10/642881 was filed with the patent office on 2004-04-29 for electronic fluid pump.
This patent application is currently assigned to Engineered Machined Products, Inc.. Invention is credited to Bader, Mark, Carlson, Jeremy S., DeGrave, Kenneth A., Lasecki, Michael P., Shiverski, Steven.
Application Number | 20040081566 10/642881 |
Document ID | / |
Family ID | 25110128 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040081566 |
Kind Code |
A1 |
Bader, Mark ; et
al. |
April 29, 2004 |
Electronic fluid pump
Abstract
A fluid pump includes a pump housing having a housing cavity
with an inlet and an outlet. An encapsulated stator assembly is
positioned within the housing cavity and at least partially defines
a fluid passage from the inlet to the outlet. A polymeric capsule
member encloses and seals the encapsulated stator assembly,
protecting the motor from, and providing heat transfer to, the
working fluid. A stator provides a magnetic field which drives a
rotor assembly. The rotor assembly rotates an impeller for pumping
fluid from the inlet to the outlet.
Inventors: |
Bader, Mark; (Gladstone,
MI) ; Lasecki, Michael P.; (Gladstone, MI) ;
Shiverski, Steven; (Perronville, MI) ; DeGrave,
Kenneth A.; (Wilson, MI) ; Carlson, Jeremy S.;
(Gladstone, MI) |
Correspondence
Address: |
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Assignee: |
Engineered Machined Products,
Inc.
Escanaba
MI
|
Family ID: |
25110128 |
Appl. No.: |
10/642881 |
Filed: |
August 18, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10642881 |
Aug 18, 2003 |
|
|
|
09777391 |
Feb 5, 2001 |
|
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|
6659737 |
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Current U.S.
Class: |
417/366 ;
417/423.14; 417/423.7 |
Current CPC
Class: |
F04D 29/588 20130101;
F04D 13/06 20130101 |
Class at
Publication: |
417/366 ;
417/423.7; 417/423.14 |
International
Class: |
F04B 039/06 |
Claims
What is claimed is:
1. A fluid pump for pumping liquid, comprising: a motor housing
assembly having an inlet housing, a stator housing assembly, and an
outlet housing; wherein the stator housing assembly includes a
substantially cylindrical metal case and an encapsulated stator
assembly enclosed and sealed by a polymeric capsule member, and the
polymeric capsule member defines a rotor cavity; an impeller
rotatably positioned in the inlet housing and having an impeller
axis; and a rotor assembly rotatably located inside the rotor
cavity and connected to the impeller for rotating the impeller for
pumping liquid from the inlet housing to the outlet housing.
2. The fluid pump of claim 1, wherein the inlet housing and outlet
housing are fastened together to secure the stator housing assembly
therebetween.
3. The fluid pump of claim 1, wherein the metal case includes
liquid flow passages formed therein by diffuser vanes and inner and
outer walls of the metal case, thereby completely defining the
liquid flow passages.
4. The fluid pump of claim 1, wherein the polymeric capsule member
comprises a thermally conductive, electrically insulative
material.
5. The fluid pump of claim 1 wherein the stator housing assembly
further includes a front cover and a rear cover plugging opposing
ends of the rotor cavity.
6. The fluid pump of claim 5, further comprising inlet diffuser
vanes formed on the front cover.
7. The fluid pump of claim 1, wherein the rotor assembly includes a
rotor with a rotor shaft.
8. The fluid pump of claim 7, wherein the rotor shaft is supported
by a front bearing and a rear bearing.
9. The fluid pump of claim 8, wherein the rear cover contains a
bearing seat for locating the rear bearing.
10. A method of manufacturing an encapsulated stator assembly,
comprising: providing a front cover and a rear cover; providing a
hollow, substantially cylindrical metal case with a longitudinal
axis and two open ends; locating a stator assembly within the metal
case; temporarily capping the two open ends and encapsulating the
stator assembly in a polymeric material; and uncapping the two ends
and attaching the front cover and the rear cover to the metal
case.
11. The method of claim 10, wherein the polymeric material is
thermally conductive and electrically insulative.
12. The method of claim 10, wherein the metal case includes liquid
flow passages formed therein by diffuser vanes and inner and outer
walls of the metal case, thereby completely defining the liquid
flow passages.
13. The method of claim 10, wherein the front cover includes
diffuser vanes formed thereon.
14. The method of claim 10, wherein encapsulating the stator
assembly in the polymeric material includes forming a cavity
therethrough.
15. The method of claim 14, wherein the front and rear covers are
each configured to receive a bearing to support a shaft disposed
within the cavity.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 09/777,391 filed Feb. 5, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a fluid pump containing an
encapsulated stator assembly that seals a pump motor and
facilitates heat transfer from the motor and the electronics to the
working fluid.
[0004] 2. Background Art
[0005] Use of fluid pumps in vehicle engine cooling systems and
various industrial applications is well known. However, typical
fluid pumps in both of these areas have inherent limitations.
[0006] Typically in engine cooling systems, a coolant pump has a
pulley keyed to a shaft. The shaft is driven by the engine via a
belt and pulley coupling, and rotates an impeller to pump the
working fluid. Fluid seals sometimes fail due to the side load from
the drive belt, which tends to allow fluid to leak past the seal
into the bearing.
[0007] U.S. Pat. No. 6,056,518, issued on May 2, 2000 to Allen et
al., describes one attempt to overcome the shortcomings of prior
art vehicle coolant pumps. The '518 patent provides a fluid pump
with a switched reluctance motor that is secured to a housing and
rotates an impeller for pumping the fluid. This design eliminates
the side load problem associated with keyed pulleys, but it is
generally not intended for use where larger industrial pumps are
required.
[0008] Industrial pumps are typically driven by an electric motor
connected to the pump via a coupling, the alignment of which is
critical. Misalignment of the coupling can result in premature pump
failure, which leads to the use of expensive constant velocity
couplings to overcome this problem. Moreover, industrial pumps are
typically air-cooled, relying on air from the surrounding
environment. The cooling air is drawn through the motor leaving
airborne dust and other contaminants deposited in the motor. These
deposits can contaminate the bearings, causing them to fail, or the
deposits can coat the windings, shielding them from the cooling air
and causing the windings to overheat and short out.
[0009] Accordingly, it is desirable to provide an improved fluid
pump which overcomes the above-referenced shortcomings of prior art
fluid pumps, while also providing enhanced fluid flow rate and
control capability while reducing costs.
SUMMARY OF THE INVENTION
[0010] The present invention provides a fluid pump with an
encapsulated stator assembly that contains a rotor cavity. A rotor
assembly, driven by a stator, is positioned within this cavity and
turns an impeller for pumping the working fluid. The encapsulated
stator assembly prevents the working fluid from directly contacting
the motor. It does, however, have an outside wall that is in
contact with the working fluid, thereby facilitating heat transfer
from the motor to the fluid.
[0011] More specifically, the present invention provides a fluid
pump including a housing having a housing cavity therein. An
encapsulated stator assembly is positioned within the housing
cavity and at least partially defines a boundary for the working
fluid. The encapsulated stator assembly contains a rotor cavity in
which a rotor assembly is located. The magnetic field generated by
a stator drives the rotor assembly, which is connected to an
impeller for pumping the fluid.
[0012] In a preferred embodiment, the encapsulated stator assembly
is a single unit, and is located inside a two-piece housing. A
stator comprising steel laminations, windings, and motor power
leads, is encapsulated in a thermally conductive, electrically
insulative polymeric capsule member. The polymeric capsule member
defines a rotor cavity having an opening. The rotor assembly,
consists of a rotor with a rotor shaft, the rotor shaft being
supported by a front bearing and a rear bearing. Also, in the
preferred embodiment, the rear bearing is located within the
encapsulated stator assembly, and the front bearing and a seal are
positioned within a front cover that plugs the rotor cavity
opening.
[0013] A diffuser is used to help direct fluid flow and thereby
increase the efficiency of the pump. The diffuser comprises an
inner wall, an outer wall, and a plurality of diffuser vanes. The
diffuser vanes are integrally molded to the outer wall of the
encapsulated stator assembly. The polymeric capsule member orients
the motor power leads with substantial circumferential symmetry
around the diffuser. The motor power leads then interface with a
circuit board assembly near the outlet of the pump. The working
fluid flows around the outside of the encapsulated stator assembly,
thereby encountering the diffuser vanes and allowing heat transfer
from the motor to the fluid. The working fluid then encounters the
encapsulated motor power leads, thereby cooling both the motor
power leads and the circuit board assembly.
[0014] In an alternative embodiment, the one piece encapsulated
stator assembly is replaced with a one piece stator housing
assembly. This change allows for larger motors to be utilized with
the pump, and thereby increases the number of applications in which
the invention may be used. The stator housing assembly includes an
encapsulated stator assembly and a substantially cylindrical metal
case which provides an outlet for a single bundle of motor power
leads and also contains diffuser vanes that fully define the
boundary of the working fluid. The encapsulated stator assembly is
enclosed and sealed by a thermally conductive, electrically
insulative polymeric capsule member that defines a motor cavity and
provides a heat transfer path to the working fluid. As in the
preferred embodiment, a rotor with a rotor shaft is located in the
motor cavity and is driven by the magnetic field generated by the
stator. The motor housing assembly comprises a front cover, a
stator housing assembly, and a rear cover.
[0015] This alternative embodiment also has a diffuser with
diffuser walls and diffuser vanes; however, there are now two sets
of diffuser vanes. The front cover is configured with a first set
of diffuser vanes and the stator housing assembly is configured
with a second set of diffuser vanes. The two covers and the stator
housing assembly are joined together and sealed in a manner to
prevent the working fluid from entering the motor cavity.
[0016] Accordingly, an object of the present invention is to
provide a fluid pump with an encapsulated stator assembly, the
encapsulated stator assembly orienting the motor components and
providing heat transfer between the motor and the working
fluid.
[0017] Another object of the invention is to provide a fluid pump
with an encapsulated stator assembly, the encapsulated stator
assembly forming a diffuser, including a plurality of diffuser
vanes. The above object and other objects, features, and advantages
of the present invention are readily apparent from the following
detailed description of the best mode for carrying out the
invention when taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 shows a longitudinal cross-sectional view of a fluid
pump in accordance with the present invention;
[0019] FIG. 2 shows a longitudinal cross-sectional view of an
encapsulated stator assembly for use with the pump shown in FIG.
1;
[0020] FIG. 3 shows a perspective view of the encapsulated stator
assembly, with the motor cavity opening toward the front and the
motor power leads toward the back;
[0021] FIG. 4 shows a rear perspective view of an impeller for use
with the pump shown in FIG. 1;
[0022] FIG. 5 shows a perspective view of a two piece pump housing
with an inlet housing toward the front and an outlet housing toward
the rear for use with the pump shown in FIG. 1;
[0023] FIG. 6 shows a perspective view of the outlet housing
corresponding with the embodiment of FIG. 1;
[0024] FIG. 7 shows a perspective view of the outlet housing of
FIG. 6, with a circuit board assembly attached;
[0025] FIG. 8 shows a side view of a fluid pump in accordance with
an alternative embodiment of the invention;
[0026] FIG. 9 shows a longitudinal cross-sectional view of the
fluid pump shown in FIG. 8;
[0027] FIG. 10 shows a perspective view of the stator housing
assembly of the fluid pump of FIG. 8;
[0028] FIG. 11 shows a longitudinal cross-sectional view of the
stator housing assembly of FIG. 10;
[0029] FIG. 12 shows a longitudinal cross-sectional view of a
second alternative embodiment of the fluid pump of FIG. 1;
[0030] FIG. 13 shows a longitudinal cross-sectional view of a seal
cartridge assembly for use with the pump shown in FIG. 12;
[0031] FIG. 14 shows a perspective view of the seal cartridge
assembly and one end of the rotor shaft with a drive pin for use
with the pump shown in FIG. 12.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] FIG. 1 shows a longitudinal cross-sectional view of a fluid
pump 10 in accordance with the present invention. A two-piece pump
housing comprises an inlet pump housing 12 and an outlet pump
housing 14. The pump housing has a housing cavity 15 therein which
contains an encapsulated stator assembly 22.
[0033] Referring to FIG. 2, the encapsulated stator assembly 22
defines a rotor cavity 17 with an opening 19. The encapsulated
stator assembly 22 comprises a polymeric capsule member 21, that
has a plurality of diffuser vanes 18 molded integrally thereon.
Polymeric capsule member 21 encloses and seals a motor stator 20
and motor power leads 32. Thus, when the fluid pump 10 is used in
an engine cooling system, the motor stator 20 and motor power leads
32 are protected from the liquid engine coolant. Motor stator 20
comprises a plurality of steel laminations 20a and a plurality of
copper windings 20b.
[0034] Returning to FIG. 1, located within rotor cavity 17 is a
rotor assembly 28, consisting of a rotor 28a and a rotor shaft 28b.
The rotor shaft 28b is supported by a front bearing 42 and a rear
bearing 40. Rear bearing 40 is located within the encapsulated
stator assembly 22. Front bearing 42 and seal 44 are located within
the front cover 26 that plugs the rotor cavity opening 19.
[0035] FIG. 3 shows a front perspective view of encapsulated motor
assembly 22. In particular, it shows diffuser vanes 18 which are of
split construction (but need not be of split construction for this
invention), and the motor power leads 32 which are oriented with
substantial circumferential symmetry around the longitudinal axis
of the encapsulated stator assembly 22. As seen in FIG. 1, motor
power leads 32 interface with a circuit board assembly 34.
[0036] Returning to FIG. 1 impeller 16 is slip fit onto the rotor
shaft 28b and secured with a buttonhead capscrew 50. A drive pin 30
transversely located through rotor shaft 28b drives impeller 16 via
slot 23.
[0037] FIG. 4 shows impeller 16 with slot 23 configured to receive
drive pin 30. FIG. 5 shows the inlet pump housing 12 attached to
the outlet pump housing 14. Outlet pump housing 14 is again shown
in FIG. 6, this time with motor power leads 32. FIG. 7 shows the
outside of pump 10 including the inlet pump housing 12, the outlet
pump housing 14, the circuit board assembly 34, and the connection
points between circuit board assembly 34 and the motor power leads
32.
[0038] Referring to FIG. 8, a fluid pump 60 is shown in accordance
with one alternative embodiment of the invention. Although similar
in function to the preferred embodiment, there are a number of
notable differences with regard to form. Rather than a two-piece
housing, this embodiment employs a three-piece housing assembly
comprising an inlet housing 62, a stator housing assembly 64, and
an outlet housing 66, assembled with bolts 68.
[0039] The stator housing assembly 64, shown in FIG. 10 and
sectioned in FIG. 11, includes an encapsulated stator assembly 75
and a substantially cylindrical metal case 73 which provides an
outlet for a single bundle of motor power leads 92 and diffuser
vanes 83 that fully define the boundary of the working fluid. The
encapsulated stator assembly 75 includes a plurality of steel
laminations 90a, a plurality of windings 90b, and a plurality of
motor power leads 92. A polymeric capsule member 77 encloses and
seals the stator assembly 90, and also defines a rotor cavity
79.
[0040] As shown in FIG. 9, a rotor assembly 82, consisting of a
rotor 82a and a rotor shaft 82b, is located within rotor cavity 79.
Rotor shaft 82b is supported by a rear bearing 96 positioned in a
bearing seat 97 within the rear cover 74 which plugs the rear
opening of the rotor cavity 79, and a front bearing 86 and seals
100 positioned within a front cover 70 which plugs the forward
opening of the rotor cavity 79. Drive pin 84 is positioned
transversely through rotor shaft 82b and drives impeller 76.
[0041] Referring to FIG. 9, unlike the preferred embodiment, this
alternative embodiment has two separate sets of diffuser vanes, the
first set 81 being configured on the front cover 70 and the second
set 83 being configured on the stator housing assembly 64.
[0042] FIGS. 10 and 11 clearly show the resultant fluid passage 88
formed between the vanes 83 and the inner and outer walls 73a,73b
of the metal case 73.
[0043] The encapsulated stator assembly 75 may be manufactured by
locating the stator assembly 90 within the substantially
cylindrical metal case 73 and temporarily capping the two open ends
of the metal case. The stator assembly 90 would then be
encapsulated in a polymeric thermally conductive, electrically
insulative material 77. The opposing ends of the metal case would
be uncapped, and the front and rear covers 70,74 would be attached
to the metal case to complete the encapsulated stator assembly
75.
[0044] FIG. 12 shows a second alternative embodiment of the fluid
pump of FIG. 1. Seal cartridge assembly 26 plugs opening 19 in
rotor cavity 17. Wear sleeve 24 is slip fit over the end of rotor
shaft 52b. An impeller 16 is slip fit onto wear sleeve 24 and is
secured to rotor shaft 52b with a buttonhead capscrew 50. A drive
pin 30 transversely located through rotor shaft 52b and wear sleeve
24 serves multiple functions. The drive pin 30 drives impeller 16
via slot 23 (similarly as shown in FIG. 4); it prevents wear sleeve
24 from rotating relative to rotor shaft 52b; it captures axial
loads from rotor assembly 52.
[0045] Some of the features and components of the seal cartridge
assembly 26 are shown in FIGS. 12 and 13. Body 27 has a wet side 31
in contact with the working fluid, such as a liquid engine coolant,
and a dry side 29. The body 27 also contains a plurality of holes
47 for attaching the seal cartridge assembly 26 to the encapsulated
stator assembly 57, using bolts 48. A seal 53 is press fit into the
body 27 and plugs an opening on the wet side 31.
[0046] Referring to FIG. 14, the wear sleeve 24 is machined to form
an inner diameter and has an axis coaxial to an axis of the body
27. A hole 25 is machined transverse to the wear sleeve axis and is
configured to receive drive pin 30. The rotor shaft 52b has a
transverse hole 56 that also receives drive pin 30.
[0047] Returning to FIG. 13, the front bearing 51, being press fit
onto the substantially cylindrical wear sleeve 24, plugs an opening
on the dry side 29. The bearing 51 and wear sleeve 24 are press-fit
into the cartridge body, and the wear sleeve 24 is slip fit over
the shaft 52b. The seal cartridge assembly 26 also contains leak
detection ports 33, shown in FIG. 14, for visual or electronic
indication of seal 53 failure.
[0048] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
* * * * *