U.S. patent application number 16/232738 was filed with the patent office on 2019-07-04 for thrust bearing placement for compressor.
The applicant listed for this patent is Johnson Controls Technology Company. Invention is credited to Matthew Lee Heisey, Paul William Snell.
Application Number | 20190203730 16/232738 |
Document ID | / |
Family ID | 67057644 |
Filed Date | 2019-07-04 |
United States Patent
Application |
20190203730 |
Kind Code |
A1 |
Heisey; Matthew Lee ; et
al. |
July 4, 2019 |
THRUST BEARING PLACEMENT FOR COMPRESSOR
Abstract
A compressor includes a shaft, a motor configured to drive the
shaft into rotation, and a thrust bearing configured to permit
rotation of the shaft and support an axial load of the shaft. The
thrust bearing is positioned about the shaft and between the motor
and an impeller of the compressor.
Inventors: |
Heisey; Matthew Lee; (York,
PA) ; Snell; Paul William; (York, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Johnson Controls Technology Company |
Auburn Hills |
MI |
US |
|
|
Family ID: |
67057644 |
Appl. No.: |
16/232738 |
Filed: |
December 26, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62611722 |
Dec 29, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 25/06 20130101;
F04D 29/0413 20130101; F04D 29/06 20130101; F04D 29/051 20130101;
F04D 29/162 20130101; F04D 17/10 20130101; F04D 29/44 20130101;
F04D 29/058 20130101 |
International
Class: |
F04D 29/041 20060101
F04D029/041; F04D 29/058 20060101 F04D029/058; F04D 29/06 20060101
F04D029/06; F04D 17/10 20060101 F04D017/10; F04D 29/44 20060101
F04D029/44 |
Claims
1. A compressor, comprising: a shaft; a motor configured to drive
the shaft into rotation; and a thrust bearing configured to permit
rotation of the shaft and to support an axial load of the shaft,
wherein the thrust bearing is positioned about the shaft and
between the motor and an impeller of the compressor.
2. The compressor of claim 1, wherein the compressor comprises a
centrifugal compressor.
3. The compressor of claim 1, wherein the compressor comprises a
hermetic overhung centrifugal compressor.
4. The compressor of claim 1, wherein the shaft extends within the
motor and beyond opposing sides of the motor.
5. The compressor of claim 1, comprising the impeller and a
diffuser passage, wherein the impeller is axially aligned with the
diffuser passage such that the impeller directs refrigerant toward
and into the diffuser passage.
6. The compressor of claim 1, comprising a casing in which the
shaft, the motor, and the thrust bearing are disposed.
7. The compressor of claim 6, comprising a bearing cavity formed
internal to the casing and in which the thrust bearing is
disposed.
8. The compressor of claim 1, wherein the thrust bearing comprises
a magnetic bearing.
9. The compressor of claim 1, wherein the thrust bearing comprises
an anti-friction bearing.
10. The compressor of claim 1, wherein the thrust bearing comprises
a lubricated hydrodynamic thrust bearing.
11. A heating, ventilation, air conditioning, and refrigerant
(HVAC&R) system comprising a compressor, wherein the compressor
comprises: a shaft; a motor configured to drive the shaft into
rotation; an impeller coupled to the shaft and configured to be
driven into rotation by the shaft; and a thrust bearing configured
to permit rotation of the shaft and to support an axial load of the
shaft, wherein the thrust bearing is positioned about the shaft and
between the motor and the impeller of the compressor.
12. The HVAC&R system of claim 11, comprising an evaporator
from which the compressor is configured to receive refrigerant.
13. The HVAC&R system of claim 11, comprising a condenser
configured to receive refrigerant from the compressor.
14. The HVAC&R system of claim 11, wherein the compressor
comprises a diffuser passage axially aligned with the impeller such
that the impeller directs refrigerant toward and into the diffuser
passage.
15. The HVAC&R system of claim 11, wherein the thrust bearing
comprises a magnetic bearing, an anti-friction bearing, or a
lubricated hydrodynamic thrust bearing.
16. A centrifugal compressor, comprising: a shaft; a motor
configured to drive the shaft into rotation; and a thrust bearing
configured to permit rotation of the shaft and to support an axial
load of the shaft, wherein the thrust bearing is configured to be
disposed within a bearing cavity of the centrifugal compressor,
about the shaft, and between the motor and an impeller of the
centrifugal compressor.
17. The centrifugal compressor of claim 16, wherein the centrifugal
compressor comprises a hermetic overhung centrifugal
compressor.
18. The centrifugal compressor of claim 16, comprising a casing in
which the shaft, the motor, and the thrust bearing are configured
to be disposed.
19. The centrifugal compressor of claim 18, wherein the bearing
cavity is formed within the casing.
20. The centrifugal compressor of claim 16, wherein the thrust
bearing comprises a magnetic bearing, an anti-friction bearing, or
a lubricated hydrodynamic thrust bearing.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of U.S.
Provisional Application No. 62/611,722, entitled "THRUST BEARING
PLACEMENT FOR COMPRESSOR," filed Dec. 29, 2017, which is hereby
incorporated by reference in its entirety for all purposes.
BACKGROUND
[0002] This application relates generally to vapor compression
systems such as chillers, and more specifically to a compressor of
a chiller.
[0003] Vapor compression systems (e.g., chillers) utilize a working
fluid, typically referred to as a refrigerant, which changes phase
between vapor, liquid, and combinations thereof in response to
being subjected to different temperatures and pressures associated
with operation of the vapor compression system. For example, a
heating, ventilation, air conditioning, and refrigeration
(HVAC&R) system may include a chiller, which is a type of vapor
compression system that cycles a refrigerant to remove heat from,
or cool, a flow of water traversing tubes that extend through a
chiller evaporator. The chilled water flow may be directed to
nearby structures to absorb heat, or provide cooling, before being
cycled back to the chiller evaporator to be cooled once again.
[0004] Chillers utilize compressors, such as centrifugal
compressors, in order to pump or otherwise move the refrigerant
about the chiller. A traditional centrifugal compressor may include
a motor which rotates a shaft in order to operate the traditional
centrifugal compressor. Unfortunately, certain operating and/or
ambient conditions may negatively impact the shaft and associated
components, reducing an efficiency of the compressor and
corresponding chiller. Accordingly, improved compressors for
chillers and/or other vapor compression systems may be desired.
SUMMARY
[0005] An embodiment includes a compressor having a shaft, a motor
configured to drive the shaft into rotation, and a thrust bearing
configured to permit rotation of the shaft and support an axial
load of the shaft. The thrust bearing is positioned about the shaft
and between the motor and an impeller of the compressor.
[0006] Another embodiment includes a heating, ventilation, air
conditioning, and refrigerant (HVAC&R) system having a
compressor. The compressor includes a shaft, a motor configured to
drive the shaft into rotation, an impeller coupled to the shaft and
configured to be driven into rotation by the shaft, and a thrust
bearing configured to permit rotation of the shaft and to support
an axial load of the shaft. The thrust bearing is positioned about
the shaft and between the motor and the impeller of the
compressor.
[0007] Another embodiment includes a centrifugal compressor having
a shaft, a motor configured to drive the shaft into rotation, and a
thrust bearing configured to permit rotation of the shaft and to
support an axial load of the shaft. The thrust bearing is
configured to be disposed within a bearing cavity of the
centrifugal compressor, about the shaft, and between the motor and
an impeller of the centrifugal compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a building that may utilize
an embodiment of a heating, ventilation, air conditioning, and
refrigeration (HVAC&R) system in a commercial setting, in
accordance with an aspect of the present disclosure;
[0009] FIG. 2 is a perspective view of an embodiment of a vapor
compression system, in accordance with an aspect of the present
disclosure;
[0010] FIG. 3 is a schematic illustration of an embodiment of the
vapor compression system of FIG. 2, in accordance with an aspect of
the present disclosure;
[0011] FIG. 4 is a schematic illustration of another embodiment of
the vapor compression system of FIG. 2, in accordance with an
aspect of the present disclosure;
[0012] FIG. 5 is a cross-sectional side view of an embodiment of a
compressor for use in the vapor compression system of FIG. 2, and
having a thrust bearing positioned between a motor of the
compressor and an impeller of the compressor, in accordance with an
aspect of the present disclosure; and
[0013] FIG. 6 is a cross-sectional side view of another embodiment
of a compressor for use in the vapor compression system of FIG. 2,
and having a thrust bearing positioned between a motor of the
compressor and an impeller of the compressor, in accordance with an
aspect of the present disclosure.
DETAILED DESCRIPTION
[0014] One or more specific embodiments will be described below. In
an effort to provide a concise description of these embodiments,
not all features of an actual implementation are described in the
specification. It should be appreciated that in the development of
any such actual implementation, as in any engineering or design
project, numerous implementation-specific decisions must be made to
achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which may vary
from one implementation to another. Moreover, it should be
appreciated that such a development effort might be complex and
time consuming, but would nevertheless be a routine undertaking of
design, fabrication, and manufacture for those of ordinary skill
having the benefit of this disclosure.
[0015] As set forth above, traditional chillers utilize
compressors, such as centrifugal compressors, in order to pump
refrigerant about the chiller. A traditional centrifugal compressor
may include a motor which rotates a shaft of the compressor in
order to operate the traditional centrifugal compressor.
Unfortunately, certain operating and/or ambient conditions, such as
certain temperatures and/or pressures, may negatively impact the
shaft and associated components, reducing an efficiency of the
compressor and corresponding chiller. For example, as the operating
temperature of the centrifugal compressor increases, the shaft of
the centrifugal compressor may thermally expand in an axial
direction. Shaft growth due to thermal expansion may impact the
axial location of the impeller within a diffuser passage of the
compressor. Because appropriate axial location of the impeller
within the diffuser passage improves efficiency of the compressor,
changes to the axial location of the impeller within the diffuser
passage due to temperature increase and corresponding thermal
expansion of the shaft may reduce efficiency of the compressor.
[0016] In accordance with present embodiments, a thrust bearing is
positioned on an impeller-side of the motor, and about the shaft.
In other words, the thrust bearing is positioned between a motor of
the compressor and an impeller of the compressor, as opposed to an
opposing non-impeller-side of the motor. The thrust bearing is
configured to permit rotation of the shaft, and to support an axial
load of the shaft against the thrust bearing. In doing so, the
axial position of the thrust bearing with respect to axially static
components of the compressor does not change. Positioning the
thrust bearing on the impeller-side of the motor (i.e., between the
motor and the impeller) and about the shaft causes a shorter shaft
length between the thrust bearing and the impeller, compared to
positioning the thrust bearing on the opposing side (i.e.,
non-impeller-side) of the motor. By reducing the shaft length
between the thrust bearing and the impeller, axial displacement of
the shaft toward the impeller (i.e., between the thrust bearing and
the impeller) caused by temperature changes (i.e., thermal
expansion) is reduced, as most of the axial displacement of the
shaft caused by thermal expansion occurs on the opposing side of
the thrust bearing. Accordingly, axial displacement of the impeller
within the diffuser passage is reduced compared to embodiments
having no thrust bearing, or a thrust bearing positioned farther
away from the impeller. Reducing the axial displacement of the
impeller improves efficiency of the compressor, as described above,
at least in part because it reduces or negates misalignment of the
impeller with respect to the diffuser passage. These and other
features will be described in detail below with respect to the
drawings.
[0017] Turning now to the drawings, FIG. 1 is a perspective view of
an embodiment of a heating, ventilation, air conditioning, and
refrigeration (HVAC&R) system 10 of a building 12 for a typical
commercial setting. The HVAC&R system 10 may include a vapor
compression system 14 that supplies a chilled liquid, which may be
used to cool the building 12. The HVAC&R system 10 may also
include a boiler 16 to supply warm liquid to heat the building 12,
and an air distribution system which circulates air through the
building 12. The air distribution system can also include an air
return duct 18, an air supply duct 20, and/or an air handler 22. In
some embodiments, the air handler 22 may include a heat exchanger
that is connected to the boiler 16 and the vapor compression system
14 by conduits 24. The heat exchanger in the air handler 22 may
receive either heated liquid from the boiler 16 or chilled liquid
from the vapor compression system 14, depending on the mode of
operation of the HVAC&R system 10. The HVAC&R system 10 is
shown with a separate air handler on each floor of building 12, but
in other embodiments, the HVAC&R system 10 may include air
handlers 22 and/or other components that may be shared between or
among floors.
[0018] FIGS. 2 and 3 are embodiments of the vapor compression
system 14 that can be used in the HVAC&R system 10. The vapor
compression system 14 may circulate a refrigerant through a circuit
starting with a compressor 32. The circuit may also include a
condenser 34, an expansion valve(s) or device(s) 36, and a liquid
chiller or an evaporator 38. The vapor compression system 14 may
further include a control panel 40 that has an analog to digital
(A/D) converter 42, a microprocessor 44, a non-volatile memory 46,
and/or an interface board 48.
[0019] Some examples of fluids that may be used as refrigerants in
the vapor compression system 14 are hydrofluorocarbon (HFC) based
refrigerants, for example, R-410A, R-407, R-134a, hydrofluoro
olefin (HFO), "natural" refrigerants like ammonia (NH.sub.3),
R-717, carbon dioxide (CO.sub.2), R-744, or hydrocarbon based
refrigerants, water vapor, or any other suitable refrigerant. In
some embodiments, the vapor compression system 14 may be configured
to efficiently utilize refrigerants having a normal boiling point
of about 19 degrees Celsius (66 degrees Fahrenheit) at one
atmosphere of pressure, also referred to as low pressure
refrigerants, versus a medium pressure refrigerant, such as R-134a.
As used herein, "normal boiling point" may refer to a boiling point
temperature measured at one atmosphere of pressure.
[0020] In some embodiments, the vapor compression system 14 may use
one or more of a variable speed drive (VSDs) 52, a motor 50, the
compressor 32, the condenser 34, the expansion valve or device 36,
and/or the evaporator 38. The motor 50 may drive a shaft of the
compressor 32, and may be powered by a variable speed drive (VSD)
52. The VSD 52 receives alternating current (AC) power having a
particular fixed line voltage and fixed line frequency from an AC
power source, and provides power having a variable voltage and
frequency to the motor 50. In other embodiments, the motor 50 may
be powered directly from an AC or direct current (DC) power source.
The motor 50 may include any type of electric motor that can be
powered by a VSD or directly from an AC or DC power source, such as
a switched reluctance motor, an induction motor, an electronically
commutated permanent magnet motor, or another suitable motor. The
motor 50, the VSD 52, or both may be separate from the compressor
32, or may be partially or fully integrated with the compressor 32.
It should be noted that, in certain embodiments, the motor 50
and/or the VSD 52 may be integral with the compressor 32. For
example, the motor 50 may be partially or entirely contained within
a casing of the compressor 32.
[0021] The compressor 32 compresses a refrigerant vapor and
delivers the vapor to the condenser 34 through a discharge passage.
In some embodiments, the compressor 32 may be a centrifugal
compressor. The refrigerant vapor delivered by the compressor 32 to
the condenser 34 may transfer heat to a cooling fluid (e.g., water
or air) in the condenser 34. The refrigerant vapor may condense to
a refrigerant liquid in the condenser 34 as a result of thermal
heat transfer with the cooling fluid. The liquid refrigerant from
the condenser 34 may flow through the expansion device 36 to the
evaporator 38. In the illustrated embodiment of FIG. 3, the
condenser 34 is water cooled and includes a tube bundle 54
connected to a cooling tower 56, which supplies the cooling fluid
to the condenser.
[0022] The liquid refrigerant delivered to the evaporator 38 may
absorb heat from another cooling fluid, which may or may not be the
same cooling fluid used in the condenser 34. The liquid refrigerant
in the evaporator 38 may undergo a phase change from the liquid
refrigerant to a refrigerant vapor. As shown in the illustrated
embodiment of FIG. 3, the evaporator 38 may include a tube bundle
58 having a supply line 60S and a return line 60R connected to a
cooling load 62. The cooling fluid of the evaporator 38 (e.g.,
water, ethylene glycol, calcium chloride brine, sodium chloride
brine, or any other suitable fluid) enters the evaporator 38 via
return line 60R and exits the evaporator 38 via supply line 60S.
The evaporator 38 may reduce the temperature of the cooling fluid
in the tube bundle 58 via thermal heat transfer with the
refrigerant. The tube bundle 58 in the evaporator 38 can include a
plurality of tubes and/or a plurality of tube bundles. In any case,
the vapor refrigerant exits the evaporator 38 and returns to the
compressor 32 by a suction line to complete the cycle.
[0023] FIG. 4 is a schematic of the vapor compression system 14
with an intermediate circuit 64 incorporated between condenser 34
and the expansion device 36. The intermediate circuit 64 may have
an inlet line 68 that is directly fluidly connected to the
condenser 34. In other embodiments, the inlet line 68 may be
indirectly fluidly coupled to the condenser 34. As shown in the
illustrated embodiment of FIG. 4, the inlet line 68 includes a
first expansion device 66 positioned upstream of an intermediate
vessel 70. In some embodiments, the intermediate vessel 70 may be a
flash tank (e.g., a flash intercooler). In other embodiments, the
intermediate vessel 70 may be configured as a heat exchanger or a
"surface economizer." In the illustrated embodiment of FIG. 4, the
intermediate vessel 70 is used as a flash tank, and the first
expansion device 66 is configured to lower the pressure of (e.g.,
expand) the liquid refrigerant received from the condenser 34.
During the expansion process, a portion of the liquid may vaporize,
and thus, the intermediate vessel 70 may be used to separate the
vapor from the liquid received from the first expansion device 66.
Additionally, the intermediate vessel 70 may provide for further
expansion of the liquid refrigerant because of a pressure drop
experienced by the liquid refrigerant when entering the
intermediate vessel 70 (e.g., due to a rapid increase in volume
experienced when entering the intermediate vessel 70). The vapor in
the intermediate vessel 70 may be drawn by the compressor 32
through a suction line 74 of the compressor 32. In other
embodiments, the vapor in the intermediate vessel may be drawn to
an intermediate stage of the compressor 32 (e.g., not the suction
stage). The liquid that collects in the intermediate vessel 70 may
be at a lower enthalpy than the liquid refrigerant exiting the
condenser 34 because of the expansion in the expansion device 66
and/or the intermediate vessel 70. The liquid from intermediate
vessel 70 may then flow in line 72 through a second expansion
device 36 to the evaporator 38.
[0024] In accordance with the present disclosure, the compressor 32
in the embodiments illustrated in, and described with respect to,
FIGS. 1-4 may include a thrust bearing positioned about a shaft of
the compressor 32. The thrust bearing is configured to permit
rotation of the shaft, and to support an axial load of the shaft
against the thrust bearing. In doing so, the axial distance between
the thrust bearing and other axially static components of the
compressor 32 does not change. Positioning the thrust bearing on
the impeller-side of the motor 50 (i.e., between the motor 50 and
the impeller of the compressor 32), in accordance with the present
disclosure, causes a shorter shaft length between the thrust
bearing and the impeller compared to, for example, positioning the
thrust bearing on the opposing side (i.e., non-impeller-side) of
the motor. By reducing the shaft length between the impeller and
the thrust bearing, which maintains its axial position with respect
to axially static components of the compressor 32, axial
displacement of the shaft caused by thermal expansion of the shaft
toward the impeller (i.e., between the thrust bearing and the
impeller) is reduced. In other words, the majority of axial growth
of the shaft, if any, due to thermal expansion occurs not within
the short shaft length between the thrust bearing and the impeller,
but instead within the longer shaft length extending from the other
end of the thrust bearing (e.g., toward the motor 50, through the
motor 50, and on the non-impeller-side of the motor 50).
Accordingly, displacement of the impeller within the diffuser
passage (due to temperature changes that cause thermal expansion of
the shaft) is reduced compared to embodiments having no thrust
bearing, or having a thrust bearing positioned farther from the
impeller (e.g., on the non-impeller-side of the motor). By reducing
displacement of the impeller, efficiency of the compressor is
improved. These and other features will be described in detail
below with respect to the drawings.
[0025] FIG. 5 is a side view of an embodiment of the compressor 32
for use in the vapor compression system 14 of FIG. 2. The
compressor 32 includes a thrust bearing 100 positioned about a
shaft 101 of the compressor 32, positioned between the motor 50 of
the compressor 32 and an impeller 102 of the compressor 32 with
respect to an axial direction 104 (e.g., along a longitudinal axis
115 of the compressor 32). The thrust bearing 100, the shaft 101,
the impeller 102, the motor 50, and other features of the
compressor 32 may be contained within a casing 103 of the
compressor 32.
[0026] As previously described, the motor 50 may be integral with
the compressor 32. The motor 50 may be configured to rotate the
shaft 101 to cause compression of refrigerant passing through the
compressor 32 (and to move the refrigerant through a corresponding
chiller or vapor compression system). For example, the shaft 101
may cause rotation of the impeller 102, which includes a set of
vanes and/or blades that gradually increases the energy of the
refrigerant and directs the refrigerant toward a diffuser passage
112 of the compressor 32. In general, the diffuser passage 112 of
the compressor 32 may include a vane, vaneless, or variable
geometry diffuser, which operates to diffuse the high-energy
refrigerant gas. That is, the diffuser passage 112 and
corresponding diffuser may convert the kinetic energy of the
refrigerant gas into pressure by gradually reducing a velocity
thereof. The refrigerant gas may then flow through a collector 113
downstream of the diffuser passage 112. The impeller 102 may be
axially positioned (e.g., with respect to direction 104 along the
longitudinal axis 115) such that the impeller 102 guides the
refrigerant toward appropriate locations of the diffuser passage
112 and corresponding diffuser. By reducing displacement of the
impeller 102, misalignment of the impeller 102 with respect to the
diffuser passage 112, which would otherwise reduce an efficiency of
the compressor 32, is reduced or negated.
[0027] As operating and/or ambient temperatures increase during
operation of the compressor 32, the shaft 101 may thermally expand
along an axial direction 104 (e.g., along the longitudinal axis 115
of the compressor 32). However, the thrust bearing 100 is
configured to permit rotation of the shaft 101 while supporting an
axial load of the shaft 101. In other words, the thrust bearing 100
maintains its axial position with respect to, for example, the
motor 50.
[0028] In accordance with present embodiments, the thrust bearing
100 is positioned between the motor 50 of the compressor 32 and the
impeller 102 of the compressor 32. In other words, the thrust
bearing 100 is positioned on an impeller-side 106 of the motor 50,
as opposed to a non-impeller-side 108 of the motor 50. By
positioning the thrust bearing 100 on the impeller-side 106 of the
motor 50, a shaft length 110 between the thrust bearing 100 and the
impeller 102 is less than if the thrust bearing 100 were disposed
on the non-impeller-side 108 of the motor 50. Thus, the available
shaft length 110 that can thermally expand between the axially
static thrust bearing 100 and the impeller 102 is small compared to
embodiments having a thrust bearing positioned farther away from
the impeller 102. Indeed, as shown, an additional shaft length 111
extending from the thrust bearing 100, through the motor 50, and
through the non-impeller-side 108 of the motor 50 is significantly
larger than the illustrated shaft length 110 between the thrust
bearing 100 and the impeller 102. By reducing the available shaft
length 110 that can thermally expand in the axial direction 104
into the impeller 102 as shown and described, an axial displacement
of the impeller 102 is reduced. Because appropriate axial location
of the impeller 102 with respect to a diffuser passage 112 of the
compressor 32 improves efficiency of the compressor 32, the
disclosed thrust bearing 100 and corresponding axial location along
the shaft 101 (e.g., on the impeller-side 106 of the motor 50, as
opposed to the non-impeller-side 108 of the motor 50) improves
efficiency of the compressor 32. It should be noted that the
compressors 32 of FIGS. 5 and 6 may be centrifugal compressors,
hermetic compressors, overhung compressors, or any combination
thereof (e.g., hermetic overhung centrifugal compressor). Further,
in FIG. 5, the thrust bearing 100 is a lubricated hydrodynamic
bearing, whereas in FIG. 6, the thrust bearing 100 is a magnetic
bearing. The above-described effects associated with the disclosed
positioning the thrust bearing 100 between the motor 50 and the
impeller 102 (i.e., along the impeller-side 106 of the motor 50) is
applicable to magnetic bearings, anti-friction bearings (e.g., oil
or refrigerant lubricated anti-friction bearings such as roller
bearings or ball bearings), lubricated hydrodynamic thrust
bearings, and any other suitable thrust bearings. It should be
noted that the thrust bearing 100 may be positioned within a cavity
105 (e.g., bearing cavity) formed within the compressor 32 (e.g.,
formed inside the casing 103 and/or with respect to other features
of the compressor 32). The cavity 105 may be configured (e.g.,
sized and/or shaped) to receive the thrust bearing 100, and the
thrust bearing 100 may be configured (e.g., sized and/or shaped) to
be disposed in the cavity 105.
[0029] FIG. 6 is cross-sectional side view of another embodiment of
the compressor 32 for use in the vapor compression system 14 of
FIG. 2. Similar to the embodiment illustrated in FIG. 5, the
compressor 32 illustrated in FIG. 6 includes the thrust bearing 100
positioned about the shaft 101 and on the impeller-side 106 of the
motor 50. Accordingly, the shaft length 110 between the thrust
bearing 100 and the impeller 102 is reduced compared to embodiments
having no thrust bearing or a thrust bearing positioned farther
from the impeller (e.g., on the non-impeller-side 108 of the motor
50). By reducing the shaft length 110 between the axially static
thrust bearing 100 and the impeller 102, axial displacement of the
shaft length 110 between the thrust bearing 100 and the impeller
102 (e.g., caused by increased temperature) is reduced compared to
traditional embodiments, thereby reducing an axial displacement of
the impeller 102 with respect to the diffuser passage 112. By
improving maintenance of the position of the impeller 102 along the
axial direction 104, efficiency of the compressor 32 is
improved.
[0030] As previously described, in FIG. 5, the thrust bearing 100
is a lubricated hydrodynamic bearing, whereas in FIG. 6, the thrust
bearing 100 is a magnetic bearing. However, any suitable thrust
bearing may be utilized in FIG. 5 and in FIG. 6. For example, the
above-described technical effects, which relate to a position of
the thrust bearing 100 and corresponding reduction of displacement
of the impeller 102 with respect to the diffuser passage 112, may
be applicable in embodiments utilizing magnetic bearings,
anti-friction bearings (e.g., oil or refrigerant lubricated
anti-friction bearings such as roller bearings or ball bearings),
lubricated hydrodynamic bearings, and any other suitable thrust
bearings.
[0031] While only certain features and embodiments have been
illustrated and described, many modifications and changes may occur
to those skilled in the art (e.g., variations in sizes, dimensions,
structures, shapes and proportions of the various elements, values
of parameters (e.g., temperatures, pressures, etc.), mounting
arrangements, use of materials, colors, orientations, etc.) without
materially departing from the novel teachings and advantages of the
subject matter recited in the claims. The order or sequence of any
process or method steps may be varied or re-sequenced according to
alternative embodiments. It is, therefore, to be understood that
the appended claims are intended to cover all such modifications
and changes as fall within the true spirit of the disclosure.
Furthermore, in an effort to provide a concise description of the
exemplary embodiments, all features of an actual implementation may
not have been described (i.e., those unrelated to the presently
contemplated best mode of carrying out the disclosure, or those
unrelated to enabling the claimed disclosure). It should be
appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation specific decisions may be made. Such a development
effort might be complex and time consuming, but would nevertheless
be a routine undertaking of design, fabrication, and manufacture
for those of ordinary skill having the benefit of this disclosure,
without undue experimentation.
* * * * *