U.S. patent application number 10/105538 was filed with the patent office on 2002-09-26 for electrically driven compressors and methods for circulating lubrication oil through the same.
This patent application is currently assigned to Kabushiki Kaisha Toyota Jidoshokki. Invention is credited to Gennami, Hiroyuki, Kuroki, Kazuhiro, Suitou, Ken.
Application Number | 20020136652 10/105538 |
Document ID | / |
Family ID | 18943302 |
Filed Date | 2002-09-26 |
United States Patent
Application |
20020136652 |
Kind Code |
A1 |
Gennami, Hiroyuki ; et
al. |
September 26, 2002 |
Electrically driven compressors and methods for circulating
lubrication oil through the same
Abstract
An oil storage area (45a) is defined on the bottom of a motor
chamber (45) of a scroll compressor (1). An oil transfer route (4a)
is defined in the portion of a center housing (4) that corresponds
to the storage area (45a). Lubricating oil L is separated from the
discharged, compressed refrigerant by an oil separator (80) and the
lubricating oil L is supplied to the rear side of a movable scroll
(20) due to a pressure differential within the compressor (1).
After lubricating slide contact portions of scroll walls (28, 30)
of the fixed and movable scrolls (2, 20), the lubricating oil L is
temporarily stored in the storage area (45a) and then is
transferred due to a refrigerant pressure differential to the
suction-side of a compression mechanism (21) via the oil transfer
route (4a). The lubricating oil L is then transferred to the oil
separator (80) together with the compressed refrigerant that is
discharged from a compression chamber (32) of the compression
mechanism (21). Thus, the lubricating oil L contained in the
discharged, compressed refrigerant can be effectively separated
from the compressed refrigerant and circulated to and from the rear
side of the movable scroll (20) in order to lubricate moving parts
within the compressor (1) using the refrigerant pressure
differentials within the compressor (1).
Inventors: |
Gennami, Hiroyuki;
(Kariya-shi, JP) ; Kuroki, Kazuhiro; (Kariya-shi,
JP) ; Suitou, Ken; (Kariya-shi, JP) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
Kabushiki Kaisha Toyota
Jidoshokki
|
Family ID: |
18943302 |
Appl. No.: |
10/105538 |
Filed: |
March 25, 2002 |
Current U.S.
Class: |
418/55.6 ;
418/1 |
Current CPC
Class: |
F04C 23/008 20130101;
F04C 29/026 20130101; F04C 27/005 20130101; F04C 29/02 20130101;
F04C 18/0215 20130101 |
Class at
Publication: |
418/55.6 ;
418/1 |
International
Class: |
F04C 018/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2001 |
JP |
2001-088168 |
Claims
1. A scroll compressor comprising: a fixed scroll and a movable
scroll having respective scroll walls, the scroll walls slidably
contacting each other and defining a compression chamber between
the fixed scroll and the movable scroll, an electric motor
rotatably driving the movable scroll, whereby a refrigerant is
drawn from a suction-side region, is compressed within the
compression chamber and is then discharged to a discharge-side
region as the movable scroll rotates relative to the fixed scroll,
wherein a refrigerant flow channel is defined from the suction side
region to the discharge side region via the compression chamber, a
motor housing defining a substantially sealed motor chamber,
wherein the electric motor is disposed within the motor chamber, a
communication path linking the refrigerant flow channel to the
motor chamber and a lubricating oil supply route defined between a
discharge-side region of the refrigerant flow channel and an area
proximal to slide contact portions of the scroll walls of the fixed
and movable scrolls, the lubricating oil supply route being
arranged and constructed so that a difference between the pressure
at the discharge-side region of the refrigerant flow channel and
the pressure at the area proximal to the slide contact portions of
the scroll walls of the fixed and movable scrolls urges lubricating
oil towards the slide contact portions of the scroll walls of the
fixed and movable scrolls via the lubricating oil supply route.
2. A scroll compressor as in claim 1, wherein the lubricating oil
supply route includes a first oil supply route and a second oil
supply route, the first oil supply route supplying the lubricating
oil to a front side of the movable scroll, and the second oil
supply route communicating with the front side of the movable
scroll and extending to the slide contact portions.
3. A method for circulating lubricating oil through an electric
compressor having a fixed scroll and a movable scroll with
respective scroll walls that slidably contact with each other and
define a compression chamber between the fixed scroll and the
movable scroll, wherein a refrigerant flow channel is defined
between a suction-side region and a discharge-side region, and a
lubricating oil supply route is defined between the discharge-side
region of the refrigerant flow channel and the area proximal to
slide contact portions of the scroll walls of the fixed and movable
scrolls, comprising: pressure-feeding lubricating oil to the slide
contact portions of the scroll walls of the fixed and movable
scrolls via the lubricating oil supply route based upon a
difference between the pressure at the discharge-side region of the
refrigerant flow channel and the pressure at the area proximal to
the slide contact portions of the scroll walls of the fixed and
movable scrolls.
4. A method as in claim 3, wherein the lubricating oil supply route
includes a first oil supply route and a second oil supply route,
the method further comprising supplying lubricating oil via the
first oil supply route to a front side of the movable scroll, and
supplying lubricating oil via the second oil supply route to the
slide contact portions of the scroll walls of the fixed and movable
scrolls.
5. A scroll compressor comprising: a compressor having a fixed
scroll and a movable scroll, the movable scroll coupled to a drive
shaft, wherein a discharge-side region is disposed in communication
with the fixed scroll, an electric motor rotatably driving the
drive shaft, and a lubricating oil route arranged and constructed
to transfer lubrication oil from the discharge-side region to slide
contact portions of the fixed and movable scrolls via the
lubricating oil supply route so as to lubricate the slide contact
portions as the refrigerant is compressed by the compressor.
6. A scroll compressor as in claim 5, wherein the lubricating oil
route has a first end and a second end that respectively
communicate with the discharge-side region and a suction-side
region of the compressor, wherein the lubricating oil route is
arranged and constructed so that the lubrication oil flows from the
discharge-side region to the slide contact portions of the fixed
and movable scrolls due to a difference in pressure between
refrigerant pressure at the discharge-side region and refrigerant
pressure at an area proximal to the slide contact portions of the
fixed and movable scrolls.
7. A scroll compressor as in claim 6, further including an oil
separator communicating with the discharge-side region, the oil
separator being arranged and constructed to separate the
lubricating oil from compressed refrigerant that has been
discharged from the compression chamber.
8. A method for circulating lubricating oil within an electrically
driven scroll compressor driven by an electric motor, the method
comprising: generating a pressure differential between a
discharge-side region of the compressor and slide contact portions
of the compressor, thereby causing lubricating oil to move via a
lubricating oil route from the discharge-side region to the slide
contact portions.
9. A method as in claim 8, wherein the pressure differential along
the lubricating oil route is generated due to refrigerant that is
compressed by the compressor.
10. A method as in claim 9, wherein a first end of the lubricating
oil route communicates with the discharge-side region and a second
end of the lubricating oil route communicates with a suction port,
the method further comprising forcing the lubrication oil from the
discharge-side region to the area proximal to the slide contact
portions due to a difference in refrigerant pressure between the
discharge-side region and the area proximal to the slide contact
portions.
11. An method as in claim 10, further comprising pressure-feeding
the lubricating oil via a lubricating oil transfer route defined
between the area proximal to the slide contact portions and the
suction-side region of the compressor due to a difference between
the refrigerant pressure at the area proximal to the slide contact
portions and the suction-side region of the compressor.
12. A method as in claim 11, further including separating the
lubricating oil from compressed refrigerant that has been
discharged from a compression chamber of the compressor.
13. A method as in claim 12, further including storing the
lubricating oil that lubricated the slide contact portions before
the stored lubricating oil is transferred to the suction-side
region.
14. A method for circulating lubricating oil within an electrically
driven scroll compressor, comprising: separating lubricating oil
from compressed refrigerant in an area proximal to and
communicating with a discharge port of the compressor, and
transferring the separated lubricating oil to slide contact
portions of scroll walls of fixed and movable scrolls via a
lubricating oil supply route using a refrigerant
pressure-differential between the area proximal to and
communicating with the discharge port and an area proximal to the
slide contact portions of the scroll walls of the fixed and movable
scrolls, wherein the slide contact portions are lubricated with the
lubricating oil .
15. An electrically driven scroll compressor, comprising: means for
separating lubricating oil from compressed refrigerant in an area
proximal to and communicating with a discharge port of the
compressor, and means for transferring the separated lubricating
oil to slide contact portions of scroll walls of fixed and movable
scrolls using a refrigerant pressure-differential between the area
proximal to and communicating with the discharge port and an area
proximal to the slide contact portions of the scroll walls of the
fixed and movable scrolls, whereby the slide contact portions are
lubricated with the lubricating oil.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to compressors driven by an
electric motor as the drive source and methods for lubricating
moving parts within the compressors.
[0003] 2. Description of Related Art
[0004] Japanese Laid-open Patent Publication No. 5-313156 discloses
a general scroll compressor that is used as a rotary compressor for
an air conditioner, refrigerator, or the like. This scroll
compressor is configured such that a movable scroll rotates or
orbits relative to a fixed scroll in order to compress a
refrigerant to a high pressure within a compression chamber defined
between the fixed scroll and the movable scroll. The compressed
refrigerant is then discharged from a discharge port defined in the
fixed scroll.
[0005] In such a scroll compressor, it would be desirable to supply
lubricating oil to portions of a fixed scroll wall that slidably
contact a movable scroll wall so as to improve the lubrication of
the portions that are in sliding contact. However, Japanese
Laid-open Patent Publication No. 5-313156 does not suggest any
specific technique for supplying lubricating oil to these portions
of the fixed scroll wall and the movable scroll wall.
SUMMARY OF THE INVENTION
[0006] Therefore, it is one object of the present teachings to
provide techniques for effectively supplying lubrication oil to
portions of a scroll type compressor that are in sliding contact.
Preferably, the scroll type compressor is driven by an electric
motor, which drives a refrigerant compression mechanism that
discharges compressed refrigerant through the fixed scroll.
[0007] According to one aspect of the present teachings, scroll
type compressors are taught that enable lubrication oil to be
readily transferred from a refrigerant discharge side of the
compressor to portions of the scroll walls of the fixed and movable
scrolls that are in sliding contact by utilizing differences in
refrigerant pressure within the compressor.
[0008] According to another aspect of the present teachings, scroll
compressors are taught that include a fixed scroll and a movable
scroll, each having an opposing scroll wall. A compression chamber
may be defined between the opposing walls of the fixed scroll and
the movable scroll. The fixed scroll preferably includes a
discharge port or discharge region for discharging compressed
refrigerant from the compression chamber. An electric motor may
drive the movable scroll via a drive shaft, so that the refrigerant
is drawn into the compression chamber from a suction side or
suction port of the compressor. As the movable scroll rotates or
orbits relative to the fixed scroll, the refrigerant is then
compressed to generate pressurized refrigerant within the
compression chamber and then the compressed or pressurized
refrigerant is discharged through the fixed scroll. More
specifically, when the movable scroll rotates or orbits relative to
the fixed scroll, the respective scroll walls partially slidably
contact each other and preferably lubricating oil is reliably
supplied to these portions of the scroll walls that are in sliding
contact. Further, the motor optionally may be disposed within a
substantially sealed motor chamber.
[0009] A refrigerant flow channel may be defined from a suction
side or suction port of the compressor through the compression
chamber to a discharge side or discharge port of the compressor and
the refrigerant preferably flows from the suction side to the
discharge side via the refrigerant flow channel. A communication
path or passage optionally may be provided to enable the
refrigerant flow channel to communicate with the motor chamber. In
this case, a so-called "stagnated state" may be created within the
motor chamber. Consequently, a portion of the refrigerant moving
through the refrigerant flow channel will reach a "stagnated state"
within the motor chamber. Moreover, if a pressure difference exists
between the refrigerant flow channel and the motor chamber, the
refrigerant will move so as to equalize the pressure difference. In
this case, heat transfer occurs between the refrigerant within the
refrigerant flow channel and the refrigerant within the motor
chamber, thereby cooling the electric motor disposed inside the
motor chamber. During this process, the amount of refrigerant that
serves to cool the electric motor is only a small portion of the
total amount of refrigerant that is moving through the refrigerant
flow channel. Thus, this technique has little effect on the
compression work being performed by the compressor.
[0010] The scroll type compressor may further include a lubricating
oil supply route. The lubricating oil supply route may serve to
supply lubricating oil, which lubricating oil has been discharged
to the discharge area, to the slide contact surfaces of the scroll
walls of the fixed and movable scrolls due to difference in
pressure between the discharged refrigerant and an area proximal to
the slide contact portions. Preferably, the lubricating oil
discharged through the fixed scroll may be separated from the
compressor refrigerant by an oil separator. Because the pressure of
the lubricating oil in the discharged refrigerant is higher than
the pressure around the slide contact portions, the lubricating oil
in the discharged refrigerant may be easily supplied to the slide
contact portions due to this difference in pressure by causing the
discharge side region to communicate with the area proximal to the
slide contact portions. In addition, the lubricating oil thus
supplied to the slide contact portions may be used to improve the
lubricating characteristics of the slide contact portions and the
sealing performance.
[0011] According to another aspect of the present teachings, the
lubricating oil supply route may include a first oil supply route
and a second oil supply route. The first oil supply route may
supply the lubricating oil to a front side of the movable scroll.
Preferably, the first oil supply route may be formed in an end
portion of a movable scroll substrate that opposes a fixed scroll
substrate. The second oil supply route may transfer the lubricating
oil, which has been supplied to the front side of the movable
scroll, to the slide contact portions. The first oil supply route
and the second oil supply route may be positioned so as to
correspond to each other, so that the lubricating oil in the
discharge region may be transferred to the slide contact portions
via the first and second oil supply routes. Therefore, the supply
of the lubricating oil to the slide contact portions may be
achieved by the first and second oil supply routes, which may have
simple configurations.
[0012] In another aspect of the present teachings, methods for
circulating the lubricating oil within electrically driven
compressors are taught and may include supplying the lubricating
oil, which lubricating oil has been discharged to a discharge area,
to the slide contact surfaces of the scroll walls of the fixed and
movable scrolls due to difference in pressure between the
discharged refrigerant and the area proximal to the slide contact
surfaces.
[0013] In another aspect of the present teachings, compressors
optionally may include an oil storage area for storing the
lubricating oil that has been transferred to the slide contact
portions via the lubricating oil supply route. In other words, this
oil storage area may be a region or space for storing the
lubricating oil that has been used to lubricate the slide contact
portions or the excess lubricating oil that has been supplied to
the slide contact portions. This oil storage area preferably may be
provided, e.g., on the bottom of the motor chamber. In that case,
the lubricating oil that has fallen from the slide contact portions
toward the bottom of the motor chamber due to gravity can be stored
in the oil storage area, which may have a relatively simple
configuration. Furthermore, the lubricating oil that has been
stored in the oil storage area can be reliably transferred to the
suction-side region via a lubricating oil transfer route.
Therefore, the lubricating oil can be reliably circulated using a
relatively simple configuration.
[0014] In another aspect of the present teachings, methods are
taught for circulating lubricating oil through an electrically
driven compressor. Such methods may include circulating lubricating
oil by supplying the lubricating oil from the discharge-side region
of the compressor to the slide contact portions, then transferring
the lubricating oil to the suction-side region of the compressor,
and finally returning the lubricating oil to the discharge-side
region again. These operations may be all performed using the
pressure differences in the refrigerant along the refrigerant flow
path or route. Therefore, the lubricating oil can be easily
circulated using differences in refrigerant pressure.
[0015] Such methods may preferably further include storing the
lubricating oil before it is transferred from the bearing mechanism
region to the suction-side region. Then, the stored lubricating oil
may be transferred from the bearing mechanism region to the
suction-side region. Therefore, the lubricating oil can be reliably
circulated using such methods.
[0016] Additional objects, features and advantages of the present
invention will be readily understood after reading the following
detailed description together with the accompanying drawings and
the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a vertical cross-sectional diagram of a
representative scroll compressor.
[0018] FIG. 2 is a perspective diagram taken along line II-II in
FIG. 1.
[0019] FIGS. 3 and 4 are partial cross-sectional diagrams
illustrating the relative positions between the first and second
oil routes at different rotational positions of a movable
scroll.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In one embodiment of the present teachings, electrically
driven compressors may include a fixed scroll and a movable scroll
that arranged and constructed to draw in a refrigerant (or cooling
medium or refrigerant), compress and highly pressurize the
refrigerant, and then discharge the pressurized refrigerant via the
fixed scroll. The compressor preferably includes a drive shaft,
which is coupled to the movable scroll, and an electric motor
rotatably driving the drive shaft. The electric motor may be housed
within a substantially sealed motor chamber. A bearing may
rotatably support the drive shaft. A refrigerant flow channel
preferably leads from a suction side of the compressor to a
discharge side of the compressor. A communication path (connecting
passage) preferably links the refrigerant flow channel to the motor
chamber. A lubricating oil supply route may be defined between a
discharge-side region of the refrigerant flow channel and portions
of the fixed scroll and the movable that slidingly contact each
other during operation. Preferably, a difference between the
pressure at the discharge-side region of the refrigerant flow
channel and at the area proximal to the slide contact portions
causes the lubricating oil to be supplied to the slide contact
portions via the lubricating oil supply route. A lubricating oil
transfer route optionally may be defined between the slide contact
portions and a suction-side region of the refrigerant flow channel.
Preferably, a difference between the pressure at the area proximal
to the slide contact portions and the suction-side region of the
compressor causes the lubricating oil, which was previously
supplied to the slide contact portions, to be transferred to the
suction-side region. Optionally, a storage area may be provided to
store lubricating oil that has lubricated the slide contact
portions before that lubricating oil is transferred via the
lubricating oil transfer route to the suction-side region of the
compressor.
[0021] In another embodiment of the present teachings, methods for
circulating lubricating oil through electrically driven compressors
are taught. Such methods may include supplying lubricating oil to
slide contact portions of the fixed scroll and the movable scroll
based upon a difference between the pressure at a discharge-side
region of a refrigerant flow channel and the pressure at the area
proximal to the slide contact portions. Further, the lubricating
oil that has lubricated the bearing optionally may be transferred
to the suction-side region of the compressor based upon a
difference between the pressure at the area proximal to the slide
contact portions and the suction-side region. In addition, after
transferring the lubricating oil to the suction-side region of the
compressor, the lubricating oil optionally may be returned to the
discharge-side region of the compressor due to refrigerant
compression operation being performed by the compression mechanism.
Optionally, after lubricating the slide contact portions, the
lubricating oil may be temporarily stored in an oil storage area
that is defined proximal to the slide contact portions.
[0022] Each of the additional features and teachings disclosed
above and below may be utilized separately or in conjunction with
other features and teachings to provide improved compressors and
methods for designing and using such compressors. A representative
example of the present invention, which example utilizes many of
these additional features and teachings both separately and in
conjunction, will now be described in detail with reference to the
attached drawings. This detailed description is merely intended to
teach a person of skill in the art further details for practicing
preferred aspects of the present teachings and is not intended to
limit the scope of the invention. Only the claims define the scope
of the claimed invention. Therefore, combinations of features and
steps disclosed in the following detail description may not be
necessary to practice the invention in the broadest sense, and are
instead taught merely to particularly describe representative
examples of the invention. Moreover, various features of the
representative example and the dependent claims may be combined in
ways that are not specifically enumerated in order to provide
additional useful embodiments of the present teachings.
[0023] The representative embodiment of the present teachings will
be applied to a scroll compressor that raises the pressure of the
introduced refrigerant by compressing it within a compression
chamber that is defined between a fixed scroll and a movable
scroll. The refrigerant is then discharged as compressed
refrigerant. Lubricating oil is compressed with the refrigerant and
also discharged with the compressed refrigerant.
[0024] A vertical cross section of the representative electrically
driven scroll compressor 1 is shown in FIG. 1. Generally speaking,
the compressor 1 includes a fixed scroll member 2, a center housing
4, a front housing 5, and a motor housing 6. These structures
generally define the compressor main body. In FIG. 1, the left-side
end face of center housing 4 is coupled to the right-side end face
of fixed scroll member 2. The motor housing 6 is coupled to the
right-side end face of the center housing 4. The front housing 5 is
coupled to the left-side end face of the fixed scroll member 2. A
drive shaft 8 is rotatably supported by the center housing 4 and
the motor housing 6 via radial bearings 10 and 12. An eccentric (or
offset) shaft 14, which is eccentric or offset relative to a drive
shaft 8, is integrally formed on the end of the drive shaft 8 on
the side of the center housing 4 (the left side in FIG. 1).
[0025] A bushing 16 is fitted onto the eccentric shaft 14 so as to
integrally rotate with the eccentric shaft 14. A balancing weight
18 is disposed on the right-side end perimeter of the bushing 16,
as shown in FIG. 1, so as to integrally rotate with the bushing 16.
A movable scroll 20 is supported on the left-side periphery of the
bushing 16 by a needle bearing 22 so as to face the fixed scroll 2
and rotate or orbit relative to the fixed scroll 2. The fixed
scroll member 2 and the movable scroll 20 basically define a
compression mechanism 21 for compressing a refrigerant. The movable
scroll 20 has a platter-shaped substrate 24. A cylindrical boss 24a
is disposed so as to protrude or project from the right-side
surface of this substrate 24, as shown in FIG. 1. The needle
bearing 22 and the radial bearing 10 generally define a bearing
mechanism 23 of the movable scroll 20.
[0026] The fixed scroll member 2 includes a platter-shaped
substrate 26. A spiral-shaped, e.g., involute-shaped, fixed scroll
wall (lap) 28 is disposed so as to protrude or project from the
right-side surface of this substrate 26, as shown in FIG. 1.
Likewise, a spiral-shaped (e.g., involute-shaped) movable scroll
wall (lap) 30 is disposed so as to protrude or project from the
left-side surface of the substrate 24 of the movable scroll 20, as
shown in FIG. 1. These scrolls 2 and 20 are preferably positioned
such that the scroll walls 28 and 30 engage each other.
[0027] Thus, the substrate 26 and fixed scroll wall 28 of the fixed
scroll 2 together with the substrate 24 and the movable scroll wall
30 of the movable scroll 20 define a crescent-shaped compression
chamber (sealed space) 32. More specifically, portions of the fixed
scroll wall 28 slidingly contact portions of the movable scroll
wall 30 at a plurality of sliding contact areas or points
(hereinafter "slide contact portions"). The movable scroll 20
revolves or orbits as the eccentric shaft 14 rotates. During this
rotating or orbiting movement, the balancing weight 18 cancels the
centrifugal force accompanying the revolution of the movable scroll
20. The eccentric shaft 14 rotates integrally with the drive shaft
8, the bushing 16 and the needle bearing 22, which are disposed
between the eccentric shaft 14 and the boss 24a of the movable
scroll 20. The eccentric shaft 14 is designed to transmit the
rotational force of the drive shaft 8 to the movable scroll 20 as
orbiting movement.
[0028] A plurality of (e.g., four) concave areas 34 are defined on
the same circumferential line at uniform angular intervals on the
left-side end face of the center housing 4, as shown in FIG. 1. A
fixed pin 36 is secured to the center housing 4 and a movable pin
38 is secured to the substrate 24 of the movable scroll 20. The
fixed pin 36 and the movable pin 38 are inserted into a concave
area 34 and fastened. As the eccentric shaft 14 rotates,
self-rotation of the movable scroll 20 is prevented by the concave
areas 34, fixed pin 36, and movable pin 38. In other words, the
concave areas 34, fixed pin 36, and movable pin 38 may define a
self-rotation prevention mechanism for the movable scroll 20.
[0029] The substrate 26 of the fixed scroll 2 may include a
reed-type discharge valve 52, which opens and closes a discharge
opening 50. This discharge valve 52 has a reed valve member 54,
which has a shape that corresponds to the discharge opening 50, and
a valve retainer 56 for holding or retaining this reed valve member
54. The reed valve member 54 and the valve retainer 56 are secured
to the substrate 26 of the fixed scroll 2 by means of a securing
bolt 58. The discharge valve 52 is disposed within a discharge
chamber 25 partially defined by the substrate 26 of the fixed
scroll 2. Preferably, the reed valve member 54 opens and closes
according to the difference in pressure between the compression
chamber 32, which communicates with the discharge opening 50, and
the discharge chamber 25. That is, when the pressure in the
compression chamber 32 is higher than the pressure in the discharge
chamber 25, the reed valve member 54 opens. Naturally, when the
pressure in the compression chamber 32 is lower than the pressure
in the discharge chamber 25, the reed valve member 54 closes. The
valve retainer 56 is configured to regulate the maximum opening of
the reed valve member 54.
[0030] An electric motor 49 is disposed within the motor housing 6.
An inverter 60 for controlling the operation of the electric motor
49 is installed on the periphery of the housing of the compressor
main body, which essentially consists of the fixed scroll 2, center
housing 4, and motor housing 6. The inverter 60 may include, e.g.,
a switching element 62 that generates a relatively large amount of
heat, and a condenser 64 that generates a relatively small amount
of heat. The inverter 60 also may include an inverter case 70 for
housing these configuration components in order to separate the
high and low heat-generating components from each other. The
inverter case 70 preferably contains a cylinder 70a, and the
switching element 62 may be disposed on the periphery of this
cylinder 70a. The inverter case 70 also may include a substrate 65
for installing the condenser 64. The cylinder 70a of inverter case
70 preferably communicates with a suction port 44. One end of the
suction port 44 preferably communicates with the fixed scroll 2
while the other end of the suction port 44 preferably communicates
with a refrigerant feedback pipe (not shown) of an external
circuit.
[0031] The switching element 62 of the inverter case 70 may be
electrically coupled to the electric motor 49 by means of three
conducting pins 66 (only one of which is shown in the figure) and
conductive wires 67 and 68. The conducting pins 66 preferably
penetrate into the motor housing 6 and the inverter case 70.
Electric current necessary for driving the electric motor 49 is
supplied via these conducting pins 66 and conductive wires 67 and
68.
[0032] The location for connecting the conductive wire 68 with the
stator coil 46a of the electric motor 49, which will be further
described below, is preferably provided on the side of the electric
motor 49 that faces the compressor mechanism 21. The inverter 60 is
secured to the compressor housing (e.g., the center housing 4
and/or the motor housing 6). The location for connecting the
electric motor 49 with the inverter 60 is preferably provided on
the periphery of the casing along its diametric direction. In other
words, this configuration produces a compact design with a much
shorter axial length than a configuration in which the inverter (or
a similar device) is disposed on the periphery along the axial
direction. Moreover, the location for connecting the electric motor
49 with the inverter 60 is provided such that these components are
close to each other. As a result, because the electric motor 49 can
be connected to the inverter 60 over the shortest distance
possible, a short connection member can be used. Consequently,
material cost and weight can be reduced, and performance can be
improved by minimizing voltage drops across the connection
member.
[0033] A stator 46 is secured to the inner surface of the motor
housing 6 and a rotor 48 is secured to the drive shaft 8. The drive
shaft 8, stator 46, and rotor 48 generally define the electric
motor 49. The stator 46 has a stator coil 46a, and by applying
electric current to this stator coil 46a, the rotor 48 and drive
shaft 8 rotate together. The electric motor 49 is preferably
disposed within a substantially sealed motor chamber 45, which is
defined within the motor housing 6 and center housing 4.
[0034] As the eccentric shaft 14 of the drive shaft 8 rotates, the
movable scroll 20 revolves (orbits), and the refrigerant introduced
from the suction port 44 (which is defined within the fixed scroll
2) flows into the space between the substrate 26 of the fixed
scroll 2 and the substrate 24 of the movable scroll 20 from the
edge of both scrolls 2 and 20. As the movable scroll 20 revolves,
the movable pin 38 slides along the circumferential (peripheral)
surface of the fixed pin 36. Then, when the eccentric shaft 14
further rotates, the movable scroll 20, which is installed on said
eccentric shaft 14 via the needle bearing 22 so as to be able to
rotate relative to the eccentric shaft 14, revolves around the
central axis of the drive shaft 8 without rotating itself. As the
movable scroll 20 revolves, the refrigerant that has been
introduced through the suction port 44 flows into the compression
chamber 32 and is guided to the center of the fixed scroll 2 while
its pressure increases. Then, the pressurized (compressed)
refrigerant flows into the discharge opening 50 that is defined in
the center of the substrate 26 of the fixed scroll 2. That is, the
discharge opening 50 communicates with the compression chamber 32
where the pressure reaches its highest value.
[0035] The center housing 4, which separates the compression
mechanism 21 from the motor chamber 45, preferably includes a
connecting passage 47. This connecting passage 47 may serve to
connect the suction region within the refrigerant flow channel,
which is defined within the compression mechanism 21 and leads from
the suction port 44 to the discharge port 86, to the motor chamber
45. In other words, the opening through which the refrigerant
enters communicates with the space 47a formed between the
peripheral surface of the substrate 24 of the movable scroll 20 and
the internal wall surface of the scroll-housing space for housing
said substrate 24. The space 47a communicates with the motor
chamber 45 via a communication hole 47b, which is defined in the
center housing 4. Thus, the space 47a and the communication hole
47b generally define the connecting passage 47.
[0036] While the compressor 1 is operating, the connecting passage
47 always communicates with the refrigerant flow channel regardless
of the position of the substrate 24 of the movable scroll 20, which
revolves inside the scroll-housing space. Consequently, heat is
transferred via the connecting passage 47 between the refrigerant
introduced into the refrigerant flow channel and the refrigerant
disposed within the motor chamber 45. That is, heat moves from the
motor chamber 45, which is at a higher temperature, to the
refrigerant flow channel, and this heat transfer cools the electric
motor 49. Moreover, when a pressure difference occurs between the
motor chamber 45 and the refrigerant suction region, refrigerant
will flow between the motor chamber 45 and the suction region via
the connecting passage 47 so as to equalize the pressure
difference. Therefore, heat is transferred along with this
refrigerant flow, and as a result, the electric motor 49 is cooled.
Accordingly, the electric motor 49 is prevented from
overheating.
[0037] Unlike known methods that utilize the motor chamber as the
refrigerant channel, the present cooling methods and apparatus are
based on so-called "stagnation cooling," which is not accompanied
by a large refrigerant flow. The introduced refrigerant directly
involved in this type of "stagnation cooling" is only a small
portion of the total introduced refrigerant flowing through the
refrigerant flow channel. Thus, the introduced refrigerant does not
significantly raise or increase the temperature of the total
introduced refrigerant. Therefore, an increase in the specific
volume of the introduced refrigerant can be prevented, thereby
eliminating the problem of reduced compression efficiency. Although
the present embodiment uses a configuration in which the inverter
60 is cooled by the introduced refrigerant, the amount of heat
generated by the inverter 60 is much less compared to the amount of
heat that is generated by the electric motor 49. Therefore, the
rise in the temperature of the introduced refrigerant caused by
cooling the inverter 60 using said introduced refrigerant is small
compared to the temperature rise that would be caused by cooling
the electric motor 49 if all of the introduced refrigerant is
supplied into the motor chamber 45. Therefore, compression
efficiency is not reduced.
[0038] Moreover, in the present embodiment, because a
low-temperature introduced refrigerant cools the electric motor 49,
an improved cooling effect can be obtained than when using
discharged refrigerant to cool the electric motor 49. Furthermore,
the present configuration, which guides the introduced refrigerant
to the motor chamber 45, does not require a sealing material to be
disposed around the drive shaft 8, which drive shaft 8 transmits
the drive force of the electric motor 49 to the compression
mechanism 21. Therefore, a simple structure can be manufactured at
a reduced cost.
[0039] The front housing 5 may include an oil separator 80 for
separating the lubricating oil within the refrigerant that has been
discharged from the discharge chamber 25. This oil separator 80 may
utilize, e.g., a separation mechanism that relies upon centrifugal
force to perform the oil separation. Thus, the oil separator 80 may
generally include an oil separation chamber 81, a cylindrical
member 82, a filter 84 installed below the cylindrical member 82,
and a storage area (lubricating oil reservoir) 85 for temporarily
storing the separated lubricating oil. A connection hole or passage
83 may be defined between the oil separation chamber 81 and the
storage area 85 in order to allow lubricating oil to pass from the
oil separation chamber 81 to the storage area 85. When the
compressed refrigerant discharged from the discharge chamber 25 is
introduced into the oil separator 80, as indicated by the curved,
solid-line arrow in FIG. 1, the compressed refrigerant collides
with the cylindrical member 82 in the oil separation chamber 81 and
descends while circling around the cylindrical member 82.
Therefore, the lubricating oil contained in the compressed
refrigerant will separate due to centrifugal force and the
lubrication oil will move, due to gravity, as indicated by the
dotted-line arrow shown in FIG. 1.
[0040] Then, after the lubricating oil passes through the
connection hole 83 and filter 84, the lubricating oil may be
temporarily stored in the storage area 85. Meanwhile, the
discharged refrigerant (from which the lubricating oil has been
separated) moves from the opening 82a of the cylindrical member 82
to a discharge port 86, and then is transferred to a condenser (not
shown) in an external circuit.
[0041] A gasket 90 is preferably disposed between the right end
face of the front housing 5 and the left end face of the fixed
scroll 2. As shown in FIG. 2, a first oil supply hole 91, which
communicates with the storage area 85, is defined near the bottom
of this gasket 90, and a second oil supply hole 93 is defined near
the top of the gasket 90. The first and second oil supply holes 91,
93 communicate with each other via an oil supply groove
(lubricating oil supply passage) 92. A first oil supply route 94
extends from the oil supply hole 93, which is defined at an edge of
the fixed scroll substrate 26, to the front side (the left side of
the substrate 24 of the movable scroll 20 in FIG. 1) of the movable
scroll 20. The first oil supply route 94 preferably has a throttled
shape. That is, the area of its oil flow channel is smaller on the
side of movable scroll 20 than on the side of the fixed scroll 2.
Therefore, it is possible to prevent an unnecessary amount of
lubricating oil from being supplied through this first oil supply
route 94.
[0042] In addition, as shown in FIGS. 1, 3 and 4, a second oil
supply route 95 for communicating lubricating oil may be defined on
the front portion of the movable scroll 20 (left side of the
movable scroll 20 as viewed in FIG. 1) that corresponds to the
first oil supply route 94. The second oil supply route 95 may
include a concave area 95a. The second oil supply route 95 may
connect the first oil supply route 94 and an area proximal to the
slide contact portions of the scroll walls 28 and 30. Therefore,
the storage area 85 of the front housing 5 communicates with the
area (peripheral area) proximal to the slide contact portions of
the scroll walls 28 and 30 via the second oil supply route 95, the
oil supply holes 91 and 93, and the lubricating oil supply route,
which includes the oil supply groove 92 and the first oil supply
route 94.
[0043] Because the second oil supply route 95 is defined on the
movable scroll substrate 24, the position of the second oil supply
route 95 relative to the first oil supply route 94 changes as the
movable scroll 20 rotates. Consequently, the concave area 95a of
the second oil supply route 95 may be configured to always
communicate with the first oil supply route 94 regardless of the
rotational position of the movable scroll 20.
[0044] The storage area 85, which is at the discharge pressure, has
a higher pressure than the peripheral area proximal to the slide
contact portions. Consequently, the lubricating oil L stored in the
storage area 85 is force-fed by the pressure difference to the
slide contact portions via the lubricating oil supply route 91-95.
The lubricating oil L stored in the storage area 85 will
hereinafter be referred to as "the lubricating oil in the
discharge-side region."
[0045] Next, changes in position of the second oil supply route 95
relative to the first oil supply route 94 and resulting changes in
the flow of the lubricating oil during this process will be
explained with reference to FIGS. 3 and 4.
[0046] The revolving motions of the movable scroll 20 can be
expressed as vertical reciprocal movements with respect to FIG. 1.
That is, while revolving, the movable scroll 20 is disposed in the
position shown in FIG. 3 or FIG. 4. In the position shown in FIG.
3, the first oil supply route 94 communicates with concave area 95a
of the second oil supply route 95. However, the lubricating oil L
that has entered the concave area 95a may be supplied to the
outside of the concave area only through an extremely minute
clearance between the fixed scroll 2 and the movable scroll 20.
Therefore, the lubricating oil L will not be positively supplied to
the slide contact portions of the fixed scroll 2 and the movable
scroll 20.
[0047] In the position shown in FIG. 4, the first oil supply route
94 communicates with the concave area 95a of the second oil supply
route 95, while a refrigerant flow channel is defined between the
fixed scroll 2 and the movable scroll wall 30. Therefore, almost of
the lubricating oil, which has been supplied from the first oil
supply route 94 to the front side of the movable scroll substrate
24, may be supplied to the slide contact portions of the fixed
scroll 2 and the movable scroll 20 via the concave area 95a of the
second oil supply route 95. As a result, the lubricating oil can
lubricate the slide contact portions and improve sealing
performance.
[0048] Meanwhile, a small amount of the lubricating oil that has
supplied to the front side of the movable scroll substrate 24 may
also be supplied to the back side (right side as viewed in FIG. 1)
of the movable scroll 20, so that the lubricating oil can lubricate
the bearing mechanism 23. The lubricating oil may then fall due to
gravity from the bearing mechanism 23 and may be stored in a
storage area 45a (concave area) formed on the bottom of the motor
chamber 45.
[0049] A transfer route 4a (hereinafter referred to as "the
lubricating oil transfer route") may preferably defined in the
lower portion (one location) of the center housing 4, which
corresponds to the storage area 45a. This transfer route 4a links
the storage area 45a of the motor chamber 45 to the suction region
(hereafter also referred to as "the suction-side region") of the
compression mechanism 21. When the lubricating oil in the storage
area 85 is being supplied to the rear side of the movable scroll
20, a portion of the discharged refrigerant is also carried along
through the lubricating oil supply route 91-95. Consequently, the
pressure in the storage area 45a becomes higher than the pressure
in the suction region, which is at the introduced refrigerant
pressure. Lubricating oil L that has lubricated the slide contact
portions of the fixed and movable scrolls 2, 20 may fall into the
storage area 45a for temporary storage.
[0050] Thereafter, the lubricating oil L, which has been
temporarily stored in the storage area 45a, is transferred by the
pressure difference to the suction side region or the suction port
44 of the compression mechanism 21 via the transfer route 4a. Then,
this lubricating oil L is transferred from the discharge opening 50
to the oil separator 80, together with the refrigerant that has
been highly pressurized in the compression chamber 32, and is
discharged. Thus, in the above representative embodiment, the first
oil supply hole 91 may serve as a first end of the lubricating oil
supply route 91-95, which first end communicates with the discharge
port 86 (the discharge side region), while the second oil supply
route 95 may serve as a second end of the lubricating oil supply
route 91-95, which second end communicates with the suction port 44
(the suction side region). The lubricating oil L contained in the
discharged refrigerant is again separated by the oil separator 80
and force-fed to the rear side of the movable scroll 20 via the
lubricating oil supply route 91-95. In this way, the lubricating
oil contained in the discharged refrigerant is circulated to and
from the rear side of the movable scroll 20. The capacity of the
storage area 45a and the size of the flow channel area of the
transfer route 4a, etc. can be appropriately set according to the
volume of lubricating oil L that will be stored in the storage area
45a.
[0051] In the scroll compressor having the above-described
configuration, when the electric motor 49 is driven, the
refrigerant returning from the evaporator (not shown) of an
external circuit is guided into the compressor 1 via the cylinder
70a and suction port 44. During this process, the refrigerant
passing through the cylinder 70a cools the inverter 60. Then, this
refrigerant is highly pressurized in the compression chamber 32 as
the movable scroll 20 revolves, and is then transferred as
discharged refrigerant to the condenser (not shown) of an external
circuit from the discharge port 86.
[0052] As described above, the lubrication oil L may be rationally
used for lubrication, because the lubricating oil L has been
separated from discharged refrigerant at the discharge region by
means of the oil separator 80. Moreover, the lubricating oil L can
be readily transferred within the compressor 1 by utilizing
pressure differences of the refrigerant disposed within the
compressor 1. Furthermore, because the lubricating oil L is
supplied to the slide contact portions of the scroll walls 28 and
29 of the fixed and movable scrolls 2 and 20, respectively, via the
lubricating oil supply route (i.e., the oil supply holes 91 and 93,
oil supply groove 92, first oil supply route 94, and second oil
supply route 95), the lubricating characteristics and durability of
the bearing mechanism 23 can be improved.
[0053] The present invention is not limited to the above
embodiment, and various kinds of applications and modifications are
possible. For example, the above embodiment modified in the
following ways:
[0054] (A) In the above representative embodiment, the lubricating
oil L that has been separated from the discharged refrigerant by
the oil separator 80 is supplied to the slide contact portions of
the scroll walls 28, 30 of the fixed and movable scrolls 2, 20.
However, it is also possible to use, for example, a configuration
in which the lubricating oil L stored in a storage area, which is
different from the oil separator 80, is supplied to the slide
contact portions using the difference in pressure between the
discharged refrigerant and the region proximal to the slide contact
portions.
[0055] (B) In the above representative embodiment, the second oil
supply route 95 is defined within the movable scroll 20. However,
the oil supply route 95 may be defined in the fixed scroll 2 in a
position corresponding to the first oil supply route 94.
* * * * *