U.S. patent application number 11/701121 was filed with the patent office on 2007-08-02 for refrigerant compressor.
Invention is credited to Yoshinori Inoue.
Application Number | 20070175239 11/701121 |
Document ID | / |
Family ID | 38320667 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070175239 |
Kind Code |
A1 |
Inoue; Yoshinori |
August 2, 2007 |
Refrigerant compressor
Abstract
A refrigerant compressor forms a refrigerant circulation circuit
with an external refrigerant circuit, and includes an oil
separation structure. The oil separation structure includes a
plurality of separation chambers for centrifugally separating oil
from refrigerant gas, an oil storage chamber for storing the oil
separated in the plurality of separation chambers, a connection
passage and an oil passage. The plurality of separation chambers
and the oil storage chamber are recessed within thickness of a
circumferential wall of a housing component so as to be juxtaposed
in a transverse direction passing across the housing component. The
connection passage connects the plurality of separation chambers,
and extends in the transverse direction along the refrigerant gas
flow in a discharge path. The oil passage connects the oil storage
chamber and the separation chambers, and extends in the transverse
direction.
Inventors: |
Inoue; Yoshinori;
(Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
3 World Financial Center
New York
NY
10281-2101
US
|
Family ID: |
38320667 |
Appl. No.: |
11/701121 |
Filed: |
January 31, 2007 |
Current U.S.
Class: |
62/469 ;
62/470 |
Current CPC
Class: |
F04B 27/109 20130101;
F25B 43/02 20130101; F25B 2400/02 20130101 |
Class at
Publication: |
62/469 ;
62/470 |
International
Class: |
F25B 43/02 20060101
F25B043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2006 |
JP |
P2006-024596 |
Claims
1. A refrigerant compressor for forming a refrigerant circulation
circuit with an external refrigerant circuit comprising: a housing
having a plurality of housing components joined together; a
compression mechanism provided in the housing, which draws
refrigerant gas from the external refrigerant circuit for
compression and discharges the compressed refrigerant gas thereto;
and an oil separation structure provided on a discharge path of the
refrigerant gas flowing from the compression mechanism toward the
external refrigerant circuit for separating oil contained in the
refrigerant gas, the oil separation structure comprising: a
plurality of separation chambers for centrifugally separating the
oil from the refrigerant gas; an oil storage chamber for storing
the oil separated in the plurality of separation chambers; wherein
the plurality of separation chambers and the oil storage chamber
are recessed within thickness of a circumferential wall of one of
the housing components so as to be juxtaposed in a transverse
direction passing across the housing component; a connection
passage connecting the plurality of separation chambers, the
connection passage extending in the transverse direction along the
refrigerant gas flow in the discharge path; and an oil passage
connecting the oil storage chamber and the separation chambers, the
oil passage extending in the transverse direction.
2. The refrigerant compressor according to claim 1, wherein the
separation chambers includes: a first separation chamber provided
on the downstream side of the compression mechanism in the
direction of the refrigerant gas flow; a second separation chamber
provided on the downstream side of the first separation chamber in
the direction of the refrigerant gas flow, the second separation
chamber being juxtaposed to the first separation chamber; wherein
the first separation chamber has an introduction passage to
introduce the refrigerant gas from the compression mechanism,
wherein the introduction passage has an opening to the first
separation chamber in a position closer to the second separation
chamber than a first axis of the first separation chamber; wherein
the connection passage connects the first separation chamber and
the second separation chamber so as to extend linearly from the
first separation chamber toward the second separation chamber, and
has two openings to each separation chamber; wherein the opening of
the connection passage to the first separation chamber is formed in
a position closer to the second separation chamber than the first
axis of the first separation chamber; and wherein the opening of
the connection passage to the second separation chamber is formed
in a position closer to the first separation chamber than a second
axis of the second separation chamber.
3. The refrigerant compressor according to claim 2 wherein the
opening of the introduction passage to the first separation chamber
and the opening of the connection passage to the first separation
chamber are formed in different height positions.
4. The refrigerant compressor according to claim 2, wherein a
cylinder is provided within the second separation chamber for
forcedly swirling the refrigerant gas.
5. The refrigerant compressor according to claim 2, wherein a
swirling flow forming member is fixedly accommodated in the second
separation chamber.
6. The refrigerant compressor according to claim 2, wherein a
separating portion is provided within the first separation chamber
for forcedly swirling the refrigerant gas.
7. The refrigerant compressor according to claim 1, wherein the
compression mechanism is a piston type.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a refrigerant compressor
including an oil separation structure for separating lubricant oil
from refrigerant gas on a discharge path from a compression
mechanism to an external refrigerant circuit.
[0002] A refrigerant compressor in vehicle air conditioners forms a
refrigerant circulation circuit with the external refrigerant
circuit, and smoothly operates a compression mechanism by adding
lubricant oil (refrigeration oil) to refrigerant gas and supplying
the oil to the compression mechanism. The refrigerant compressor
includes an oil separation structure provided on the discharge path
of refrigerant gas for preventing the oil from the flowing out to
the external refrigerant circuit with the refrigerant gas (for
example, refer to Japanese Patent Application Publication No.
2000-2183). If the oil flows out to the external refrigerant
circuit, the oil adheres to the inner wall surface of a condenser
or an evaporator in the external refrigerant circuit to deteriorate
the heat exchange efficiency in the external refrigerant
circuit.
[0003] The oil separation structure disclosed in Japanese Patent
Application Publication No. 2000-2183 is provided in a rear housing
constituting the housing of the refrigerant compressor.
Specifically, an accommodating chamber is formed on the discharge
path in the rear housing, and a partition is incorporated in the
accommodating chamber. The partition divides the accommodating
chamber into a separation chamber for oil separation and a
communication chamber connected with the separation chamber by a
communication passage. The separation chamber is connected with a
discharge chamber for refrigerant gas by an introduction passage in
the rear housing, and also with a crank chamber within the
refrigerant compressor by a supply passage in the rear housing. The
communication chamber is connected with a muffler chamber by a
delivery passage formed in the rear housing, the muffler chamber
being connected with the external refrigerant circuit.
[0004] In the oil separation structure disclosed in Japanese Patent
Application Publication No. 2060-2183, refrigerant gas discharged
to the discharge chamber is introduced to the separation chamber
through the introduction passage, and swirls along the inner
circumferential surface in the separation chamber. The oil mist
contained in the refrigerant gas is then separated by centrifugal
force. The refrigerant gas after oil separation is delivered to the
external refrigerant circuit through the communication passage, the
communication chamber, the delivery passage and the muffler
chamber. The oil separated in the separation chamber is supplied to
the crank chamber through the supply passage, with the refrigerant
gas for displacement control of the refrigerant compressor. The oil
supplied to the crank chamber is supplied to each sliding part
within the refrigerant compressor and exhibits lubricating and
cooling effects therein.
[0005] In such a refrigerant compressor, further reduction in the
lubricant oil flowing out to the external refrigerant circuit is
strongly demanded, and the reduction in the outflow of the oil
seriously requires improvement in oil separation capability in the
oil separation structure. In the oil separation structure of
Japanese Patent Application Publication No. 2000-2183, it is
conceivable to ensure a sufficient swirling distance of refrigerant
gas in the separation chamber for the improvement in oil separation
capability. A radially or axially enlarged separation chamber
(accommodating chamber) may be formed in the rear housing to ensure
the sufficient swirling distance of refrigerant gas. This
enlargement of the rear housing results in increase in size of the
refrigerant compressor.
[0006] The present invention is directed to a refrigerant
compressor capable of improving oil separation capability without
enlargement of the size thereof.
SUMMARY OF THE INVENTION
[0007] In accordance with an aspect of the present invention, a
refrigerant compressor forms a refrigerant circulation circuit with
an external refrigerant circuit. The refrigerant compressor
includes a housing, a compression mechanism and an oil separation
structure. The housing has a plurality of housing components joined
together. The compression mechanism is provided in the housing,
which draws refrigerant gas from the external refrigerant circuit
for compression and discharges the compressed refrigerant gas
thereto. The oil separation structure is provided on a discharge
path of the refrigerant gas flowing from the compression mechanism
toward the external refrigerant circuit for separating oil
contained in the refrigerant gas. The oil separation structure
includes a plurality of separation chambers for centrifugally
separating the oil from the refrigerant gas, an oil storage chamber
for storing the oil separated in the plurality of separation
chambers, a connection passage and an oil passage. The plurality of
separation chambers and the oil storage chamber are recessed within
thickness of a circumferential wall of one of the housing
components so as to be juxtaposed in a transverse direction passing
across the housing component. The connection passage connects the
plurality of separation chambers, and extends in the transverse
direction along the refrigerant gas flow in the discharge path. The
oil passage connects the oil storage chamber and the separation
chambers, and extends in the transverse direction.
[0008] Other aspects and advantages of the invention will become
apparent from the following description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The features of the present invention that are believed to
be novel are set forth with particularity in the appended claims.
The invention together with objects and advantages thereof, may
best be understood by reference to the following description of the
presently preferred embodiments together with the accompanying
drawings in which:
[0010] FIG. 1 is a longitudinal sectional view showing a compressor
according to an embodiment of the present invention;
[0011] FIG. 2 is a partial cross sectional view showing an oil
separation structure of the compressor;
[0012] FIG. 3 is a cross sectional view as seen from the line
III-III of FIG. 2 showing the oil separation structure; and
[0013] FIG. 4 is a partial cross sectional view showing another oil
separation structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] An embodiment of a variable displacement swash plate
compressor for vehicle air conditioners according to the
refrigerant compressor of the present invention will now be
described with reference to FIGS. 1 to 3. In the following
description, the direction of arrow Y1 shown in FIG. 1 corresponds
to the "front" and "rear" (longitudinal) direction of the variable
displacement swash plate compressor, and the direction of arrow Y2
shown in FIG. 2 corresponds to the "upper" and "lower" (vertical)
direction thereof.
[0015] As shown in FIG. 1, the housing of the variable displacement
swash plate compressor (hereinafter referred to simply as a
"compressor") 10 includes a cylinder block 11, a front housing 12
fixedly joined to a front end of the cylinder block 11, and a rear
housing 13 fixedly joined to a rear end of the cylinder block 11
through a valve plate assembly 14. Each of the cylinder block 11,
the front housing 12 and the rear housing 13 serves as a housing
component. The cylinder block 11 has a cylindrical shape and a
substantially cylindrical wall or an outer circumferential wall 40.
A plurality of cylinder bores 11a are formed in the cylinder block
11 in the longitudinal direction of the compressor 20. The front
housing 12 has a cylindrical shape bottomed at the front end
thereof, and the rear housing 13 has a cylindrical shape covered at
the rear end thereof.
[0016] The cylinder block 11 and the front housing 12 rotatably
support a rotary shaft 16. The rotary shaft 16 is connected to a
vehicle engine through a clutch mechanism such as an
electromagnetic clutch, and the rotary shaft 16 is driven by the
vehicle engine through the clutch mechanism when the vehicle engine
is operated.
[0017] The cylinder block 11 and the front housing 12 form a crank
chamber 15. In the crank chamber 15, a rotary support 19 is fixedly
mounted on the rotary shaft 16 so as to be integrally rotatable
with the rotary shaft 16. In the crank chamber 15, the rotary shaft
16 supports a swash plate 20 so as to be slidable and tiltable in
the axial direction of the rotary shaft 16. A hinge mechanism 21 is
interposed between the rotary support 19 and the swash plate 20,
and enables the swash plate 20 to tilt relative to the rotary shaft
16 and integrally rotate with the rotary shaft 16. In the cylinder
block 11, the cylinder bores 11a are formed through the cylinder
block 11 at equal intervals around the rotary shaft 16, and each
cylinder bore 11a accommodates a single-headed piston 22. One end
of each cylinder bore 11a is closed by the front surface of the
valve plate assembly 14. The rear end surface of the associated
piston 22 and the front surface of the valve plate assembly 14 form
a compression chamber (not shown) in each cylinder bore 11a. The
volume of the compression chamber is changed according to
reciprocation of the associated piston 22. Each piston 22 is
connected to an outer peripheral portion of the swash plate 20
through a pair of shoes 30 to convert rotating motion of the swash
plate 20 to reciprocating linear motion of the piston 22 through
the shoes 30.
[0018] The rear surface of the valve plate assembly 14 and the rear
housing 13 form a suction chamber 23 and a discharge chamber 24.
The valve plate assembly 14 has a plurality of suction ports 25 and
suction valves 26 in correspondence with each piston 22. The
refrigerant gas in the suction chamber 23 is drawn into the
compression chamber through the suction port 25 and the suction
valve 26 by movement from top dead center toward bottom dead center
of each piston 22 associated with rotation of the rotary shaft 16.
The valve plate assembly 14 has a plurality of discharge ports 27
and discharge valves 28 in correspondence with each piston 22. The
refrigerant gas drawn into the compression chamber is compressed to
a predetermined pressure by movement from bottom dead center toward
top dead center of the piston 22 associated with rotation of the
rotary shaft 16, and discharged to the discharge chamber 24 through
the discharge port 27 and the discharge valve 28. The rotary shaft
16, the rotary support 19, the swash plate 20, the piston 22 and
the compression chamber form a compression mechanism within the
housing of the compressor 10.
[0019] A cover 51 is coupled with an upper portion of the
circumferential wall 40 of the cylinder block 11 through a gasket
50. A muffler chamber 17a is formed by the cover 51 and the gasket
50. As shown in FIGS. 2 and 3, an oil separation structure S is
provided under the muffler chamber 17a on the circumferential wall
40 of the cylinder block 11. The refrigerant gas is introduced into
the oil separation structure S for oil separation and is discharged
to the muffler chamber 17a. An introduction passage 18 is formed in
the valve plate assembly 14 and the cylinder block 11 to connect
the discharge chamber 24 to the oil separation structure S. The
refrigerant gas discharged to the discharge chamber 24 from the
compression mechanism is introduced into the oil separation
structure S through the introduction passage 18.
[0020] A refrigerant circulation circuit for vehicle air
conditioners is composed of the compressor 10 and an external
refrigerant circuit 29. The external refrigerant circuit 29
includes a condenser 29a, an expansion valve 29b and an evaporator
29c. A refrigerant passage 39 connects the muffler chamber 17a to
the condenser 29a of the external refrigerant circuit 29. The
pressure pulsation of the refrigerant gas discharged to the muffler
chamber 17a is attenuated by an expansion type muffler effect of
the muffler chamber 17a. The discharge chamber 24, the introduction
passage 18, the oil separation structure S, the muffler chamber 17a
and the refrigerant passage 39 form a discharge path for passing
the refrigerant gas discharged from the compression mechanism and
delivered to the external refrigerant circuit 29. The refrigerant
gas discharged to the muffler chamber 17a flows to the condenser
29a, the expansion valve 29b, the evaporator 29c, and is drawn to
the compression mechanism through the suction chamber 23.
[0021] A bleed passage 32, a supply passage 33 and a control valve
34 are provided within the housing of the compressor 10. The bleed
passage 32 includes a passage 32a formed in the axial center of the
rotary shaft 16 and a through hole 32b formed in the cylinder block
11 and the valve plate assembly 14, and connects the crank chamber
15 to the suction chamber 23. The supply passage 33 connects the
discharge chamber 24 to the crank chamber 15, and the control valve
34 is disposed in the supply passage 33. The difference between the
amount of the high-pressure discharge gas introduced to the crank
chamber 15 through the supply passage 33 and the amount of the
refrigerant gas flowing out from the crank chamber 15 through the
bleed passage 32 is controlled by adjusting the opening size of the
control valve 34, and the pressure in the crank chamber 15 is
determined. The difference between the pressure in the crank
chamber 15 and the pressure in the compression chamber is changed
in accordance with change in pressure in the crank chamber 15, and
the inclination angle of the swash plate 20 is changed. As a
result, the stroke of the piston 22 or the displacement of the
compressor 10 is adjusted.
[0022] The oil separation structure S of the compressor 10 will
then be described. As shown in FIGS. 1 and 2, the circumferential
wall 40 of the cylinder block 11 is formed in a substantially
cylindrical shape around the rotary shaft 16 so as to have a
predetermined thickness on the outer circumferential side of each
cylinder bore 11a. The circumferential wall 40 has a square
pole-like projecting portion 40a under the cover 51 through the
gasket 50. The oil separation structure S is provided in the
projecting portion 40a. The projecting portion 40a is a connecting
part to be connected with the cover 51 so as to form the muffler
chamber 17a. Thus, the oil separation structure S is provided using
the existing projecting portion 40a, not adding a special part.
[0023] As shown in FIGS. 2 and 3, the projecting portion 40a of the
cylinder block 11 is provided with a first separation chamber 41, a
second separation chamber 42, and an oil storage chamber 43, which
are vertically recessed. The separation chambers 41, 42 and the oil
storage chamber 43 constitute the oil separation structure S. The
gasket 50 closes the openings of the first separation chamber 41
and the oil storage chamber 43 at the upper surface of the
projecting portion 40a. The first separation chamber 41, the second
separation chamber 42 and the oil storage chamber 43 are recessed
within the thickness of the circumferential wall 40 (projecting
portion 40a) of the cylinder block 11, and juxtaposed in the
transverse, or horizontal direction, viewed from the front end of
the compressor 10. The transverse direction indicates the direction
to linearly pass across an outer peripheral portion of the cylinder
block 11 where the cylinder bores 11a are not located. The second
separation chamber 42 is disposed next to the first separation
chamber 41 in the transverse direction, and the oil storage chamber
43 is disposed next to the second separation chamber 42 in the
transverse direction. Preferably, the separation chambers 41, 42
and the oil storage chamber 43 are located in horizontal direction
when the compressor 10 is installed in the refrigeration
circulation circuit. The second separation chamber 42 is provided
so as to be located slightly closer to the front side than the
first separation chamber 41.
[0024] The first separation chamber 41 is provided on the
downstream side of the discharge chamber 24 (compression mechanism)
along the direction of refrigerant gas flow in the discharge path
and centrifugally separates the oil contained in the refrigerant
gas. An inner circumferential surface 41a of the first separation
chamber 41 is formed cylindrically with a circular section. An
opening or an outlet 18a of the introduction passage 18 is opened
on the inner circumferential surface 41a of the first separation
chamber 41. The outlet 18a of the introduction passage 18 is formed
in a position closer to the second separation chamber 42 than the
first axis L1 of the first separation chamber 14. The introduction
passage 18 linearly extends from the discharge chamber 24 to the
first separation chamber 41 in the axial direction of the rotary
shaft 16. Therefore, the refrigerant gas flowing in the
introduction passage 18 is introduced to the first separation
chamber 41 through the outlet 18a so as to flow along the inner
circumferential surface 41a of the first separation chamber 41. The
refrigerant gas introduced to the first separation chamber 41
swirls along the inner circumferential surface 41a, whereby the oil
mist contained in the refrigerant gas is separated by the
centrifugal force.
[0025] As shown by the two-dot chain line of FIG. 2 and the dash
line of FIG. 3, a first oil passage 44 extends in the transverse
direction. The first separation chamber 41 communicates with the
oil storage chamber 43 through the first oil passage 44. A first
oil inlet 44a or one opening of the first oil passage 44 is opened
on the inner circumferential surface 41a of the first separation
chamber 41, and a first oil outlet 44b or the other opening thereof
is opened to the oil storage chamber 43. The oil separated from the
refrigerant gas in the first separation chamber 41 is introduced to
the first oil passage 44 through the first oil inlet 44a, and
discharged to the oil storage chamber 43 through the first oil
outlet 44b. The first oil inlet 44a is formed on the bottom side of
the first separation chamber 41 and located below the outlet 18a of
the introduction passage 18.
[0026] The second separation chamber 42 is provided on the
downstream side of the first separation chamber 41 in the direction
of refrigerant gas flow in the discharge path to centrifugally
separate the oil contained in the refrigerant gas. An inner
circumferential surface 42a of the second separation chamber 42 is
formed cylindrically with a circular section. The second separation
chamber 42 is connected with the muffler chamber 17a through a
through-hole 50a formed in the gasket 50. A swirling flow forming
member 45 is press-fitted to the upper side of the second
separation chamber 42. The swirling flow forming member 45 is
formed by a cylinder 45a and a flange 45b integrally formed
therewith. The cylinder 45a has a diameter smaller than that of the
inner circumferential surface 42a of the second separation chamber
42. The flange 45b radially extends from the upper end of the
cylinder 45a. The flange 45b has a diameter slightly larger than
that of the second separation chamber 42.
[0027] The cylinder 45a side of the swirling flow forming member 45
is inserted into the second separation chamber 42, and the
peripheral end of the flange 45b is pressed onto the inner
circumferential surface 42a of the second separation chamber 42,
whereby the swirling flow forming member 45 is fixedly accommodated
in the second separation chamber 42. In this accommodated state,
the cylinder 45a is disposed concentrically with the second axis 12
of the second separation chamber 42, and separated from the inner
circumferential surface 42a of the second separation chamber 42. An
annular space is formed by the outer circumferential surface of the
cylinder 45a and the inner circumferential surface 42a of the
second separation chamber 42 so that refrigerant gas can be swirled
therein. The second separation chamber 42 is divided from the
muffler chamber 17a by the flange 45b. The second separation
chamber 42 is connected with the muffler chamber 17a through the
inside of the cylinder 45a.
[0028] A connection passage 46 is formed between the first
separation chamber 41 and the second separation chamber 42 in the
projecting portion 40a to connect the first separation chamber 41
to the second separation chamber 42. The connection passage 46 is
extended in the transverse direction. The first separation chamber
41 communicates with the second separation chamber 42 through the
connection passage 46. One opening of the connection passage 46 is
opened on the inner circumferential surface 41a of the first
separation chamber 41, and forms a gas inlet 46a of refrigerant gas
from the first separation chamber 41 to the connection passage 46.
The other opening of the connection passage 46 is opened on the
inner circumferential surface 42a of the second separation chamber
42, and forms a gas outlet 46b of refrigerant gas from the
connection passage 46 to the second separation chamber 42. Namely,
the refrigerant gas swirled in the first separation chamber 41
flows in the connection passage 46 and is delivered into the second
separation chamber 42.
[0029] The gas inlet 46a of the connection passage 46 is formed in
a position closer to the second separation chamber 42 than the
first axis L1 of the first separation chamber 41. Further, the gas
outlet 46b of the connection passage 46 is formed in a position
closer to the first separation chamber 41 than the second axis L2
of the second separation chamber 42. The connection passage 46 is
formed so as to linearly extend from the first separation chamber
41 to the second separation chamber 42. The gas inlet 46a and gas
outlet 46b of the connection passage 46 are formed vertically
higher than the outlet 18a of the introduction passage 18, and the
gas outlet 46b is formed in a position opposed to the outer
circumferential surface of the cylinder 45a.
[0030] The second separation chamber 42 is connected to the oil
storage chamber 43 by a second oil passage 47 extending in the
transverse direction. A second oil inlet 47a or one opening of the
second oil passage 47 is opened on the inner circumferential
surface 42a of the second separation chamber 42, and a second oil
outlet 47b or the other opening thereof is opened to the oil
storage chamber 43. The oil separated from the refrigerant gas
within the second separation chamber 42 enters into the second oil
passage 47 through the second oil inlet 47a, and is discharged to
the oil storage chamber 43 through the second oil outlet 47b.
Further, the oil storage chamber 43 is connected with the crank
chamber 15 by an oil supply passage (not shown) formed in the
cylinder block 11.
[0031] The refrigerant gas discharged to the discharge chamber 24
successively flows in the introduction passage 18, the first
separation chamber 41, the connection passage 46, the second
separation chamber 42 (in detail, the inside of the cylinder 45a),
and the muffler chamber 17a, and is discharged to the external
refrigerant circuit 29. Therefore, the discharge chamber 24, the
introduction passage 18, the first separation chamber 41, the
connection passage 46, the second separation chamber 42, and the
muffler chamber 17a form a discharge path in the housing of the
compressor 10 for passing the refrigerant gas discharged from the
compression mechanism to the external refrigerant circuit 29. The
introduction passage 18, the first separation chamber 41, the
second separation chamber 42, the oil storage chamber 43, the first
oil passage 44, the connection passage 46, and the second oil
passage 47, form the oil separation structure S for separating the
oil contained in the refrigerant gas flowing from the discharge
chamber 24 to the external refrigerant circuit 29 on the discharge
path.
[0032] The oil separation mechanism by the oil separation structure
S will then be described. The flow of refrigerant gas is shown by
the two-dot chain line of FIG. 3. The refrigerant gas discharged to
the discharge chamber 24 is introduced to the first separation
chamber 41 through the introduction passage 18, and swirled along
the inner circumferential surface 41a in the first separation
chamber 41. Then, the oil mist contained in the refrigerant gas is
separated by the centrifugal force. In the inner circumferential
surface 41a of the first separation chamber 41, the outlet 18a of
the introduction passage 18 is located lower than the gas inlet 46a
of the connection passage 46. Therefore, the refrigerant gas
introduced into the first separation chamber 41 through the outlet
18a is introduced to the gas inlet 46a not directly but after
ascending while swirling along the inner circumferential surface
41a. The oil separated from the refrigerant gas is collected on the
bottom side of the first separation chamber 41 by its own weight.
However, since the gas inlet 46a of the connection passage 46 is
located on the upper side in the inner circumferential surface 41a,
the oil collected in the first separation chamber 41 is hardly
taken to the second separation chamber 42 through the connection
passage 46.
[0033] The refrigerant gas which contains low amount of oil after
the oil separation enters from the first separation chamber 41 into
the connection passage 46 through the gas inlet 46a, flows in the
connection passage 46, and is then introduced to the second
separation chamber 42 through the gas outlet 46b and swirls along
the cylinder 45a and the inner circumferential surface 42a of the
second separation chamber 42. The oil mist which is not separated
in the first separation chamber 41 and is still contained in the
refrigerant gas, is separated by the centrifugal force. At this
time, since the gas outlet 46b of the connection passage 46 is
formed opposing to the outer circumferential surface of the
cylinder 45a, the refrigerant gas delivered to the second
separation chamber 42 is not introduced into the cylinder 45a
directly from the lower end of the cylinder 45a, but introduced
into the cylinder 45a after descending while being forced to swirl
around the cylinder 45a. The refrigerant gas from which the oil is
separated is discharged to the muffler chamber 17a through the
inside of the cylinder 45a and further discharged to the external
refrigerant circuit 29.
[0034] The oil separated in the first separation chamber 41 enters
into the first oil passage 44 through the first oil inlet 44a, and
is discharged into the oil storage chamber 43 through the first oil
outlet 44b. The oil separated in the second separation chamber 42
enters into the second oil passage 47 through the second oil inlet
47a, and is discharged into the oil storage chamber 43 through the
second oil outlet 47b. Consequently, the oil separated from the
refrigerant gas is stored in the oil storage chamber 43. The oil
stored in the oil storage chamber 43 is supplied to the crank
chamber 15 through the oil supply passage due to the pressure
difference between the first and second separation chambers 41, 42
(a discharge pressure area) and the crank chamber 15 (a
low-pressure area). The oil supplied to the crank chamber 15 is
supplied to each sliding part such as a connection part between the
piston 22 and the shoe 30 or a connection part between the shoe 30
and the swash plate 20 to exhibit lubricating and cooling
effects.
[0035] The illustrated embodiment has the following advantages.
(1) The first separation chamber 41, the second separation chamber
42 and the oil storage chamber 43 are arranged in the transverse
direction to pass across the projecting portion 40a within the
thickness of the circumferential wall 40 of the cylinder block 11
(housing component), and the first separation chamber 41 and the
second separation chamber 42 are connected by the connection
passage 46 extending in the transverse direction. Therefore, while
the refrigerant gas is passed through the first separation chamber
41 and the second separation chamber 42 and sent to the external
refrigerant circuit 29, the oil contained in the refrigerant gas is
centrifugally separated in the first separation chamber 41 and then
further centrifugally separated in the second separation chamber
42. Accordingly, the swirling distance of the refrigerant gas on
its path through the oil separation structure S becomes long, as
compared to, for example, a case in which the refrigerant gas is
swirled only within the first separation chamber 41. Thus, the oil
separation capability can be improved. Although the two separation
chambers 41 and 42 are provided in the circumferential wall 40 of
the cylinder block 11 for extending the swirling distance of
refrigerant gas, the thickness of the circumferential wall 40 is
not increased since the two separation chambers 41 and 42 are not
formed continuously in the thickness direction (vertical direction)
of the circumferential wall 40, but juxtaposed in the transverse
direction. Therefore, under the restriction of being within the
thickness of the cylinder block 11, a long swirling distance of
refrigerant gas can be ensured without enlarging the cylinder block
11, and improvement in oil separation capability can be attained
without enlargement of the size of the compressor 10. (2) The first
separation chamber 41, the second separation chamber 42 and the oil
storage chamber 43 are provided within the thickness of the
circumferential wall 40 of the cylinder block 11, and the
connection passage 46 connecting the first separation chamber 41 to
the second separation chamber 42 is formed so as to extend in the
transverse direction. The first oil passage 44 and the second oil
passage 47 connecting the separation chambers 41 and 42 to the oil
storage chamber 43, respectively, are formed so as to extend in the
transverse direction. Therefore, the oil separation structure S,
which is improved in oil separation capability without enlargement
of the cylinder block 11 by forming each passage 44, 46, 47 in the
thickness direction (vertical direction) of the circumferential
wall 40, can be provided without enlargement of the size of the
compressor 10. (3) The first separation chamber 41 is provided
within the thickness of the circumferential wall 40 of the cylinder
block 11, and its depth is restricted. Therefore, if the oil
separation structure S is composed of only the first separation
chamber 41, the oil separated in the first separation chamber 41 is
easily taken to the external refrigerant circuit 29. However, by
providing the second separation chamber 42, the oil can be further
separated in the second separation chamber 42 even if taken from
the first separation chamber 41 to the second separation chamber 42
through the connection passage 46. Accordingly, the take-out of oil
to the external refrigerant circuit 29 can be suppressed without
increasing the depth of the separation chamber or enlarging the
cylinder block 11. (4) The gas inlet 46a of the connection passage
46 in the first separation chamber 41 is located on the upper side
of the first separation chamber 41, so that the oil once stored in
the first separation chamber 41 is hardly taken to the second
separation chamber 42. (5) In the inner circumferential surface 41a
of the first separation chamber 41, the outlet 18a of the
introduction passage 18 and the gas inlet 46a of the connection
passage 46 are formed in different positions in the height
direction. The gas inlet 46a of the connection passage 46 is higher
than the outlet 18a of the introduction passage 18. Therefore, the
refrigerant gas introduced to the first separation chamber 41 can
be prevented from being immediately introduced to the gas inlet 46a
and delivered to the second separation chamber 42, as compared to a
case in which the outlet 18a of the introduction passage 18 is
formed at the same height as the gas inlet 46a of the connection
passage 46. The swirling distance of the refrigerant gas in the
first separation chamber 41 can be thus ensured to improve the oil
separation capability. (6) The gas outlet 46b of the connection
passage 46 is formed in a position opposed to the outer
circumferential surface of the cylinder 45a. Therefore, the
refrigerant gas delivered to the second separation chamber 42 can
be prevented from being immediately discharged to the muffler
chamber 17a through the inside of the cylinder 45a without swirling
around the cylinder 45a, as compared to a case in which the gas
outlet 46b is located lower than the cylinder 45a. Namely, the
refrigerant gas delivered to the second separation chamber 42 can
be swirled around the cylinder 45a, and the oil separation
capability can be improved, as compared to a case in which the gas
outlet 46b is located lower than the cylinder 45a. (7) The
connection passage 46 is linearly formed in a position where the
refrigerant gas swirling in the first separation chamber 41 can be
delivered to the second separation chamber 42 without changing the
direction of the swirling flow. Therefore, the flow velocity of the
refrigerant gas delivered from the first separation chamber 41 to
the second separation chamber 42 is not reduced, and the
deterioration of oil separation capability resulted from reduction
in flow velocity can be suppressed. (8) The connection passage 46
is formed in a position connecting the first separation chamber 41
to the second separation chamber 42 at a short distance. Therefore,
the refrigerant gas can pass through the connection passage 46
without reduction in flow velocity, and the deterioration of oil
separation capability resulted from reduction in flow velocity can
be suppressed. (9) The cylinder 45a is provided within the second
separation chamber 42, and the refrigerant gas can be forcedly
swirled by the cylinder 45a. Therefore, the oil separation
capability in the second separation chamber 42 can be improved as
compared to a case in which the refrigerant gas swirls along the
inner circumferential surface 42a of the second separation chamber
42 without a cylinder, and almost all the oil contained in
refrigerant gas is separated in the second separation chamber 42.
Consequently, the take-out of oil to the external refrigerant
circuit 29 can be substantially eliminated.
[0036] The above-mentioned embodiment of the present invention may
be modified as follows.
[0037] In the above-mentioned embodiment, as shown in FIG. 4, a
cylindrical or columnar separating portion 52 may be protrusively
provided on the bottom surface of the first separation chamber 41,
so that the refrigerant gas introduced in the first separation
chamber 41 forcedly swirls around the separating portion 52.
[0038] The swirling flow forming member 45 may be eliminated from
the second separation chamber 42, so that the oil is centrifugally
separated only by swirling along the inner circumferential surface
42a without the cylinder 45a.
[0039] In the projecting portion 40a of the cylinder block 11,
three or more separation chambers may be provided along the
transverse direction of the circumferential wall 40. In this case,
the oil storage chamber 43 is narrowed, and the separation chambers
successively arranged in the direction of refrigerant gas flow are
connected by a connection passage so that the refrigerant gas is
successively passed through each separation chamber.
[0040] The oil separation structure S may be provided on the
circumferential wall of the front housing 12 or the rear housing 13
other than the cylinder block 11.
[0041] In the circumferential wall 40 of the cylinder block 11, the
first separation chamber 41, the oil storage chamber 43 and the
second separation chamber 42 may be successively provided in this
order in the transverse direction.
[0042] The sectional area of the connection passage 46 or the
introduction passage 18 can be set smaller than that in the
embodiment as far as pressure loss permits, whereby the flow
velocity of refrigerant gas from the passages is increased by the
throttle effect to enhance the oil separation capability.
[0043] The compression mechanism is not limited to a piston type
but can be, for example, a scroll type, a vane type, a helical type
or the like.
[0044] Therefore, the present examples and embodiments are to be
considered as illustrative and not restrictive, and the invention
is not to be limited to the details given herein but may be
modified within the scope of the appended claims.
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