U.S. patent application number 12/414058 was filed with the patent office on 2009-10-01 for variable displacement compressor.
Invention is credited to Masahiro Kawaguchi, Naofumi Kimura, Masakazu Murase, Toru ONISHI, Hiromi Ueda, Naoya Yokomachi.
Application Number | 20090241766 12/414058 |
Document ID | / |
Family ID | 40823324 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090241766 |
Kind Code |
A1 |
ONISHI; Toru ; et
al. |
October 1, 2009 |
VARIABLE DISPLACEMENT COMPRESSOR
Abstract
A variable displacement compressor includes a housing, a rotary
shaft, a bearing, a seal member, a shaft seal chamber, a discharge
refrigerant passage and a partition. The partition is provided in
the shaft seal chamber for partitioning the shaft seal chamber into
a first seal chamber to which the discharge refrigerant passage is
opened and a second seal chamber part of the periphery of which is
formed by the bearing and the seal member. The partition is
provided with a first guide passage through which refrigerant
containing lubricating oil flowed from the discharge refrigerant
passage into tho first seal chamber is substantially all supplied
to the seal member of the second seal chamber.
Inventors: |
ONISHI; Toru; (Kariya-shi,
JP) ; Yokomachi; Naoya; (Kariya-shi, JP) ;
Murase; Masakazu; (Kariya-shi, JP) ; Ueda;
Hiromi; (Kariya-shi, JP) ; Kimura; Naofumi;
(Kariya-shi, JP) ; Kawaguchi; Masahiro;
(Kariya-shi, JP) |
Correspondence
Address: |
Locke Lord Bissell & Liddell LLP;Attn: IP Docketing
Three World Financial Center
New York
NY
10281-2101
US
|
Family ID: |
40823324 |
Appl. No.: |
12/414058 |
Filed: |
March 30, 2009 |
Current U.S.
Class: |
92/13 ;
415/111 |
Current CPC
Class: |
F04B 27/1054 20130101;
F04B 39/123 20130101; F04B 27/109 20130101; F04B 27/1072 20130101;
F04B 27/1036 20130101; F04B 27/1081 20130101 |
Class at
Publication: |
92/13 ;
415/111 |
International
Class: |
F04B 53/00 20060101
F04B053/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2008 |
JP |
2008-092160 |
Aug 21, 2008 |
JP |
2008-213131 |
Claims
1. A variable displacement compressor comprising; a housing having
a crank chamber; a rotary shaft disposed in the crank chamber with
at least one end thereof exposed outside the housing; a bearing
disposed in the housing for rotatably supporting the rotary shaft;
a seal member disposed in the housing at a position between the
exposed end of the rotary shaft and the bearing for preventing
refrigerant mixed with lubricating oil from leaking out of the
housing along the rotary shaft; a shaft seal chamber defined by the
housing, the rotary shaft, the bearing and the seal member; a
discharge refrigerant passage formed in the rotary shaft, wherein
the refrigerant flows into the shaft seal chamber through the
discharge refrigerant passage; and a partition provided in the
shaft seal chamber for partitioning the shaft seal chamber into a
first seal chamber to which the discharge refrigerant passage is
opened and a second seal chamber part of the periphery of which is
formed by the bearing and the seal member, wherein the partition is
provided with a first guide passage through which the refrigerant
flowed from the discharge refrigerant passage into the first seal
chamber is substantially all supplied to the seal member of the
second seal chamber.
2. The variable displacement compressor according to claim 1,
further comprising a lug plate fixed on the rotary shaft for
rotation therewith, wherein the shaft seal chamber is defined by
the housing, the rotary shaft, the lug plate, the bearing and the
seal member.
3. The variable displacement compressor according to claim 2,
wherein the partition is provided on the lug plate.
4. The variable displacement compressor according to claim 1,
wherein the partition is provided on the rotary shaft.
5. The variable displacement compressor according to claim 1,
wherein the first guide passage is formed between the end of the
partition and the outer surface of the rotary shaft.
6. The variable displacement compressor according to claim 5,
wherein the first guide passage is formed along the outer surface
of the rotary shaft and toward the seal member.
7. The variable displacement compressor according to claim 1,
wherein the first seal chamber is defined between the partition and
the rotary shaft so that a sectional area of the first seal chamber
decreases from a position adjacent to the discharge refrigerant
passage toward the first guide passage.
8. The variable displacement compressor according to claim 1,
wherein the partition is further provided with a second guide
passage through which the refrigerant flowed through the first
guide passage is allowed to flow along an outer circumferential
surface of the seal member.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a variable displacement
compressor and more particularly to a structure for lubricating a
seal member sealing a rotary shaft of the variable displacement
compressor.
[0002] Japanese Patent Application Publication No. 4-179874
discloses a swash plate compressor including a crankcase, a rotary
shaft, a radial bearing and a lip seal. The crankcase has therein a
crank chamber. The rotary shaft is supported by the radial bearing
and one end of the rotary shaft is exposed outside the crankcase.
The lip seal serves to seal the rotary shaft. The crankcase, the
rotary shaft, the radial bearing and the lip seal cooperate to form
a space. The rotary shaft has therein a pressure control passage
through which compressed refrigerant gas flows into the crank
chamber. In addition, the rotary shaft has therein an oil feed hole
for interconnecting the pressure control passage and the space. A
part of the compressed refrigerant gas flows into the crank chamber
through the pressure control passage, the oil feed hole, the space
and the clearances in the radial bearing. Refrigerant gas contains
lubricating oil in the form of a mist, which lubricates various
sliding surfaces in the crank chamber.
[0003] Japanese Patent Application Publication No. 2006-307700
discloses a swash plate compressor wherein a partition is provided
in a shaft seal chamber for separating a lip seal and a bearing and
a clearance is formed between the partition and a rotary shaft. The
compressor of this publication includes a first passage and a
second passage. The first passage interconnects the crank chamber
and the shaft seal chamber and allows refrigerant gas containing
lubricating oil and flowing from the crank chamber to pass
therethrough. The second passage is formed between the lug plate
fixed on the rotary shaft and the housing so as to interconnect the
bearing and the crank chamber. In this structure of the compressor,
refrigerant gas circulates through the crank chamber, the first
passage, a region of the shaft seal chamber between the lip seal
and the partition, the clearance between the partition and the
rotary shaft, a region of the shaft seal chamber between the
partition and the bearing, the bearing and the second passage. Such
circulation makes it easier for refrigerant gas containing
lubricating oil to flow into the region of the shaft seal chamber
between the lip seal and the partition, so that the lip seal is
lubricated efficiently.
[0004] In the compressor according to the former publication, the
sliding surfaces between the rotary shaft and the lip seal are
lubricated by lubricating oil contained in the refrigerant gas
flowed into the space through the oil feed hole. Because the oil
feed hole extends only in the radial direction of the rotary shaft,
however, the refrigerant gas flowing into the space through the oil
feed hole moves radially outward of the space under the centrifugal
force and then passes through the radial bearing. Therefore, the
lubricating oil fails to be supplied in an adequate amount to the
sliding surfaces between the rotary shaft and the lip seal and such
poor lubrication may deteriorate the reliability of the lip
seal.
[0005] In the compressor according to the latter publication, a
part of refrigerant gas in the discharge chamber flows through a
discharge refrigerant passage formed in the rotary shaft into the
region of the shaft seal chamber between the partition and the
bearing, and then flows into the crank chamber through the bearing
and the second passage. However, the lubricating oil contained in
the refrigerant gas flowed into the region of the shaft seal
chamber between the partition and the bearing tends to reside in
the region of the shaft seal chamber adjacent to the housing under
the influence of the centrifugal force. In addition, the
lubricating oil contained in the refrigerant gas flowed into the
region of the shaft seal chamber between the partition and the
bearing through the discharge refrigerant passage is difficult to
flow into the region of the shaft seal chamber between the lip seal
and the partition because the partition is provided in the shaft
seal chamber for separating the lip seal and the bearing and also
the clearance between the partition and the rotary shaft is vary
small. Therefore, the lubricating oil fails to be supplied in an
adequate amount to the sliding surfaces between the lip seal and
the rotary shaft and such poor lubrication may deteriorate the
reliability of the lip seal.
[0006] The present invention is directed to a variable displacement
compressor wherein the durability of the seal member in sealing the
rotary shaft is improved, thereby enhancing the reliability of the
seal member.
SUMMARY OF THE INVENTION
[0007] In accordance with an aspect of the present invention, there
is provided a variable displacement compressor that includes a
housing, a rotary shaft, a bearing, a seal member, a shaft seal
chamber, a discharge refrigerant passage and a partition. The
housing has a crank chamber. The rotary shaft is disposed in the
crank chamber with at least one end thereof exposed outside the
housing. The bearing is disposed in the housing for rotatably
supporting the rotary shaft. The seal member is disposed in the
housing at a position between the exposed end of the rotary shaft
and the bearing for preventing refrigerant mixed with lubricating
oil from leaking out of the housing along the rotary shaft. The
shaft seal chamber is formed by the housing, the rotary shaft, the
bearing and the seal member. The discharge refrigerant passage is
formed in the rotary shaft. The refrigerant flows into the shaft
seal chamber through the discharge refrigerant passage. The
partition is provided in the shaft seal chamber for partitioning
the shaft seal chamber into a first seal chamber to which the
discharge refrigerant passage is opened and a second seal chamber
part of the periphery of which is formed by the bearing and the
seal member. The partition is provided with a first guide passage
through which the refrigerant flowed from the discharge refrigerant
passage into the first seal chamber is substantially all supplied
to the seal member of the second seal chamber.
[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 variable
displacement compressor according to a first embodiment of the
present invention;
[0011] FIG. 2 is an enlarged longitudinal sectional view showing a
shaft seal chamber and its related parts of the variable
displacement compressor of FIG. 1;
[0012] FIG. 3 is an enlarged fragmentary longitudinal sectional
view showing a shaft seal chamber and its related parts of a
variable displacement compressor according to a second embodiment
of the present invention;
[0013] FIG. 4 is an enlarged fragmentary longitudinal sectional
view showing a shaft seal chamber and its related parts of a
variable displacement compressor according to a third embodiment of
the present invention;
[0014] FIG. 5 is an enlarged fragmentary longitudinal sectional
view showing a shaft seal chamber and its related parts of a
variable displacement compressor according to a fourth embodiment
of the present invention;
[0015] FIG. 6 is an enlarged fragmentary longitudinal sectional
view showing a shaft seal chamber and its related parts of a
variable displacement compressor according to a fifth embodiment of
the present invention; and
[0016] FIG. 7 is an enlarged fragmentary longitudinal sectional
view showing a shaft seal chamber and its related parts of a
variable displacement compressor according to a sixth embodiment of
the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] The following will describe the variable displacement
compressors according to the embodiments of the present invention
with reference to the accompanying drawings. Referring firstly to
FIG. 1, the variable displacement compressor of the first
embodiment is designated by reference numeral 1 and will be
hereinafter referred to merely as a compressor 1. The compressor 1
forms a part of refrigeration system (not shown) in which
refrigerant gas mixed with lubricating oil is sealed. Carbon
dioxide is preferably used as the refrigerant gas. It is noted that
the front and rear of the compressor 1 in the following description
are indicated by arrows directed in opposite directions in FIG. 1.
The compressor 1 includes a cylinder block 2 having a plurality of
cylinder bores 2A. A front housing 3 is joined to the front end of
the cylinder block 2 and has therein a crank chamber 4. A rear
housing 6 is joined to the rear end of the cylinder block 2 through
a valve plate assembly 5 and has a discharge chamber 16 and a
suction chamber 17.
[0018] The discharge chamber 16 and the suction chamber 17 are
communicable with the cylinder bores 2A via the valve plate
assembly 5. More specifically, the valve plate assembly 5 has a set
of a discharge port 5A, a discharge valve (not shown), a suction
port 5B and a suction valve (not shown) for each cylinder bore 2A.
The discharge port 5A interconnects the cylinder bore 2A and the
discharge chamber 16 and the suction port 5B interconnects the
cylinder bore 2A and the suction chamber 17, respectively. The
discharge chamber 16 is connected to one end of the external
refrigeration system through an outlet port (not shown) of the
compressor 1 and the suction chamber 17 is connected to the other
end of the external refrigeration system through an inlet port (not
shown) of the compressor 1.
[0019] A drive shaft 7 is disposed in the crank chamber 4 at the
center of the front housing 3 and the cylinder block 2. The drive
shaft 7 has a large-diameter portion adjacent to the cylinder block
2, a tapered portion that tapers forward from the front end of the
large-diameter portion and a small-diameter portion that extends
forward from the front end of the tapered portion. A lug plate 11
is fixed on the drive shaft 7 at the front end of the
large-diameter portion thereof for rotation therewith within the
crank chamber 4. The lug plate 11 is rotatably supported by a
thrust bearing 12 provided between the rear surface 3A of the front
wall of the front housing 3 and the front surface of the lug plate
11. In addition, the lug plate 11 is rotatably supported by a
radial roller bearing 8 inserted in the front housing 3 at such a
position that the front portion of the drive shaft 7 is also
rotatably supported by the radial roller bearing 8 through the lug
plate 11. The rear portion of the drive shaft 7 is rotatably
supported by a radial roller bearing 9 inserted in the cylinder
block 2. Thus, the drive shaft 7 is rotatably supported by the
radial roller bearings 8, 9 and serves as the rotary shaft of the
present invention. The front end of the drive shaft 7 is exposed
outside the front housing 3 and connected to a drive source (not
shown). The rear end of the drive shaft 7 is located in a space 45
formed in the rear end of the cylinder block 2.
[0020] A swash plate 13 is mounted on the large-diameter portion of
the drive shaft 7 behind the lug plate 11 so as to be tiltable
relative to the axis of the drive shaft 7 and also slidable along
the axial direction of the drive shaft 7. The swash plate 13 has on
the side thereof adjacent to the lug plate 11 a connection 13A and
a pair of guide pins 13B mounted on the connection 13A. The lug
plate 11 has on the side thereof adjacent to the swash plate 13 a
pair of guide holes 11A. With the paired guide pins 13B inserted in
the paired guide holes 11A, the swash plate 13 and the lug plate 11
are connected to each other so as to be rotatable together. A
piston 14 is disposed in each cylinder bore 2A and connected to the
swash plate 13 through a pair of shoes 15. The shoes 15 convert the
oscillating motion of the swash plate 13 into the reciprocating
motion of the piston 14.
[0021] A lip seal 10 is mounted on the drive shaft 7 at a position
between the small-diameter portion of the drive shaft 7 and the
front housing 3 in front of the lug plate 11 and the radial roller
bearing 8 for sealing the drive shaft 7. The lip seal 10 has in the
rear end thereof a tapered portion tapering rearward and having an
outer circumferential surface 10B. The lip seal 10 serves as a seal
member for sealing the drive shaft 7. The lip seal 10 serves to
prevent refrigerant gas and lubricating oil in the crank chamber 4
from leaking out of the front housing 3 along the outer
circumferential surface of the drive shaft 7. A shaft seal chamber
22 is defined in the front housing 3 by the front housing 3, the
small-diameter portion and the tapered portion of the drive shaft
7, the radial roller bearing 8, the lip seal 10 and the lug plate
11.
[0022] The discharge chamber 16 communicates with the crank chamber
4 via a supply passage through which refrigerant gas in the
discharge chamber 16 flows into the crank chamber 4. The supply
passage will be described below. A control valve 18 is disposed in
the rear housing 6 and has a throttle (not shown) that regulates
the flow of refrigerant gas passing through the supply passage for
controlling the pressure Pc in the crank chamber 4. The control
valve 18 communicates with the discharge chamber 16 through a
passage 41 that is formed in the rear housing 6 and also with a
passage 42 that is formed in the rear housing 6. The passage 42 is
in communication with the space 45 of the cylinder block 2 via a
passage 43 that is formed in the valve plate assembly 5 and a
passage 44 that is formed in the cylinder block 2. The passages 41,
42, 43, 44 and the space 45 provide a part of the supply
passage.
[0023] The drive shaft 7 includes a first shaft portion 7A which is
of a substantially hollowed cylindrical shape having one end
thereof opened and a second shaft portion 7B which is also of a
hollowed cylindrical shape having opposite two ends thereof opened
and is press-fitted in the first shaft portion 7A, as shown in FIG.
1. An axial passage 31 is formed centrally in the first shaft
portion 7A and the second shaft portion 7B and communicates with
the space 45 of the cylinder block 2 through the opening 7E formed
at the rear end of the drive shaft 7. An annular passage 32 is
formed between the inner circumferential surface of the first shaft
portion 7A and the outer circumferential surface of the second
shaft portion 7B. A lip seal 47 is provided at the rear end of the
drive shaft 7 in the space 45 for shutting off the fluid
communication between the axial passage 31 and the annular passage
32. An O-ring 7C is held between the inner circumferential surface
of the first shaft portion 7A and the outer circumferential surface
of the second shaft portion 7B at the front end of the passage 32.
A slanted passage 33 is formed in the drive shaft 7 at an angle
relative to the axis of the drive shaft 7 and serves as the
discharge refrigerant passage of the present invention. The slanted
passage 33 extends from the front end of the axial passage 31 to an
outer circumferential surface 7F of the tapered portion of the
drive shaft 7 and is opened at 33A of the slanted passage 33 to the
shaft seal chamber 22. Thus, the slanted passage 33 interconnects
the axial passage 31 and the shaft seal chamber 22. The axial
passage 31 and the slanted passage 33 provide a part of the supply
passage.
[0024] Referring to FIG. 2, the structure of the shaft seal chamber
22 and its related parts will be described in detail. An annular
partition 21 having an L-shape section is disposed between the lip
seal 10 and the lug plate 11 in the shaft seal chamber 22. The
partition 21 is located so as to cover the opening 33A of the
slanted passage 33 and fixed to the front end of the lug plate 11
for rotation therewith. Thus, the shaft seal chamber 22 is
partitioned by the partition 21 into two chambers, namely, a first
seal chamber 22A to which the slanted passage 33 is opened and a
second seal chamber 22B part of the periphery of which is formed by
the radial roller bearing 8 and the lip seal 10.
[0025] Clearance A is formed between the inner circumferential
surface 21A of the partition 21 and the outer circumferential
surface 7D of the small-diameter portion of the drive shaft 7
facing the inner circumferential surface 21A, serving as the first
guide passage of the present invention. Therefore, the refrigerant
gas flowed into the first seal chamber 22A through the slanted
passage 33 flows into the second seal chamber 22B through the
clearance A. The refrigerant gas flowed into the second seal
chamber 22B is substantially all directed to move to the lip seal
10 along the outer circumferential surface 7D of the small-diameter
portion of the drive shaft 7 and then passes close to the lip seal
10.
[0026] The front housing 3 has in the front wall thereof a passage
34. The rear surface 3A of the front wall of the front housing 3 is
formed with a groove that extends in the radial direction of the
drive shaft 7. By being covered by the front surface of the thrust
bearing 12, the groove is formed into a radial passage 35. One end
of the above passage 34 is opened to the second seal chamber 22B of
the shaft seal chamber 22 and the other is connected to the radial
passage 35 at one end thereof adjacent to the drive shaft 7. The
other end of the radial passage 35, which is far from drive shaft
7, is opened to a region in the crank chamber 4 adjacent to the
inner periphery of the front housing 3.
[0027] A space 36 is defined behind the radial roller bearing 8 by
the front housing 3, the radial roller bearing 8, the lug plate 11
and the thrust bearing 12. The radial roller bearing 8 includes an
annular bearing race 8A having a section of a channel shape opened
radially inward and a bearing body 8B disposed in the bearing race
8A and having a plurality of needles arranged circumferentially at
a spaced interval. As shown in FIG. 2, clearance d1 is formed
between the inner circumferential surface of the bearing race 8A
and the outer circumferential surface of the lug plate 11.
Therefore, refrigerant gas and lubricating oil in the second seal
chamber 22B are allowed to flow into the space 36 through the
clearance d1 between the bearing race 8A and the lug plate 11 and
the interior of the radial roller bearing 8.
[0028] The thrust bearing 12 includes a pair of bearing races 12A
and 12B each having an L-shape section, and a bearing body 12C. The
paired bearing races 12A and 12B cooperate to form a hollow disc
and the bearing body 12C has a plurality of needles arranged
circumferentially at a spaced interval. The paired bearing races
12A and 12B hold the bearing body 12C with clearances d2 formed
between the inner ends of the bearing races 12A, 12B and between
the outer ends of the bearing races 12A, 12B, respectively.
Therefore, refrigerant gas and lubricating oil in the space 36 are
allowed to flow into the region in the crank chamber 4 adjacent to
the inner periphery of the front housing 3 through the clearances
d2 between the bearing races 12A, 12B and the interior of the
thrust bearing 12. That is, the space 36 is in communication with
the second seal chamber 22B of the shaft seal chamber 22 via the
radial roller bearing 8 and also with the region in the crank
chamber 4 adjacent to the inner periphery of the front housing 3
via the thrust bearing 12. The shaft seal chamber 22, the passages
34 and 35 provide a part of the supply passage. The shaft seal
chamber 22, the clearance d1 between the bearing race 8A and the
lug plate 11, the interior of the radial roller bearing 8, the
space 36, the clearances d2 between the bearing races 12A, 12B and
the interior of the thrust bearing 12 also provide a part of the
supply passage.
[0029] The crank chamber 4 communicates with the suction chamber 17
via a bleed passage through which refrigerant gas in the crank
chamber 4 is released into the suction chamber 17. The drive shaft
7 has therein a radial passage 46 at a position between the lug
plate 11 and the swash plate 13, interconnecting the crank chamber
4 and the annular passage 32 of the drive shaft 7 and allowing the
refrigerant gas in the crank chamber 4 to flow into the annular
passage 32. The annular passage 32 is in communication with the
suction chamber 17 via a passage 48 formed in the cylinder block 2
and a passage 49 formed in the valve plate assembly 5. The passages
46, 32, 48 and 49 provide the aforementioned bleed passage.
[0030] The operation of the compressor 1 of the first embodiment
will be described with reference to FIG. 1. When the drive shaft 7
is driven to rotate by the drive source, the swash plate 13 is
rotated with the lug plate 11 thereby to cause each piston 14 to
reciprocate in the cylinder bore 2A through the pair of shoes 15.
During the reciprocating motion of the piston 14, refrigerant gas
in the external refrigeration system is drawn into the cylinder
bore 2A through the suction chamber 17 and the suction port 5B for
compression. The refrigerant gas in the cylinder bore 2A is
compressed by the piston 14 and then discharged into the discharge
chamber 16 through the discharge port 5A. Major part of the
refrigerant gas in the discharge chamber 16 flows out of the
compressor 1 into the external refrigeration system.
[0031] On the other hand, a part of the refrigerant gas in the
discharge chamber 16 flows into the control valve 18 through the
passage 41. When the refrigerant gas flowing into the control valve
18 passes through the throttle, the flow of the refrigerant gas is
regulated and the temperature of the refrigerant gas is decreased,
accordingly. The refrigerant gas with a decreased temperature in
the control valve 18 then flows into the first seal chamber 22A
through the passages 42, 43, 44, the space 45, the axial passage 31
and the slanted passage 33 in this order.
[0032] As shown in FIG. 2, the first seal chamber 22A and the
second seal chamber 225 are in communication with each other via
the clearance A formed between the inner circumferential surface
21A of the partition 21 and the outer circumferential surface 7D of
the small-diameter portion of the drive shaft 7 facing the inner
circumferential surface 21A. Therefore, the refrigerant gas flowed
into the first seal chamber 22A flows along the outer
circumferential surface 7D of the drive shaft 7 into the second
seal chamber 22B through the clearance A. The refrigerant gas
flowed into the second seal chamber 22B through the first seal
chamber 22A and the clearance A is substantially all supplied to
the lip seal 10 that is located in front of the partition 21 and
then passes close to the sliding surfaces between the drive shaft 7
and the lip seal 10.
[0033] Lubricating oil contained in the form of a mist in the
refrigerant gas supplied to the lip seal 10 lubricates the sliding
surfaces between the drive shaft 7 and the lip seal 10. In
addition, the refrigerant gas, whose temperature is decreased when
passing through the throttle of the control valve 18 (refer to FIG.
1), cools the sliding surfaces between the drive shaft 7 and the
lip seal 10 when supplied to the lip seal 10.
[0034] A part of the refrigerant gas which has passed close to the
lip seal 10 flows into the crank chamber 4 through the passages 34
and 35. The rest of the refrigerant gas flows into the crank
chamber 4 through the radial roller bearing 8, the space 36 and the
thrust bearing 12. The radial roller bearing 8 and the thrust
bearing 12 are lubricated by the lubricating oil contained in the
refrigerant gas flowing through such bearings 8 and 12.
[0035] Referring back to FIG. 1, the pressure Pc is created in the
crank chamber 4 by the refrigerant gas flowed into the crank
chamber 4. The variable pressure difference between the pressure Pc
in the crank chamber 4 and the pressure in the cylinder bore 2A
causes the inclination angle of the swash plate 13 to vary, thus
determining the displacement of the compressor 1. The refrigerant
gas flowed into the crank chamber 4 then flows into the suction
chamber 17 through the passages 46, 32, 48, 49.
[0036] In the above-described compressor 1 including the shaft seal
chamber 22 and the slanted passage 33 that supplies refrigerant gas
containing lubricating oil to the shaft seal chamber 22,
refrigerant gas is supplied into the shaft seal chamber 22 through
the slanted passage 33. By virtue of the provision of the partition
21 in the shaft seal chamber 22 for partitioning the shaft seal
chamber 22 into the first seal chamber 22A and the second seal
chamber 22B and also of the clearance A between the partition 21
and the drive shaft 7 for allowing the refrigerant gas flowed into
the second seal chamber 22B through the first seal chamber 22A and
the clearance A to be substantially all supplied to the lip seal
10, substantially all the refrigerant gas flowed into the second
seal chamber 22B passes close to the sliding surfaces between the
drive shaft 7 and the lip seal 10. Thus, an adequate amount of
lubricating oil is supplied to the sliding surfaces between the
drive shaft 7 and the lip seal 10. Therefore, the durability of the
lip seal 10 in sealing the drive shaft 7 is improved, thereby
enhancing the reliability of the lip seal 10.
[0037] Referring to FIG. 3, a part of the variable displacement
compressor of the second embodiment is shown. The compressor of the
second embodiment differs from that of the first embodiment in that
the radial roller bearing 8 of the first embodiment is replaced by
a plain bearing 51. In the following description of the second and
other embodiments, like reference numerals or symbols denote the
like elements or parts of the compressor 1 used in the description
of the first embodiment and the detailed description of such
elements or parts will be omitted. In the second embodiment, the
lug plate 11 is rotatably supported by the plain bearing 51
inserted in the front housing 3.
[0038] The plain bearing 51 is provided by a cylindrical metal
member with the opposite ends thereof opened. In the second
embodiment, a part of the refrigerant gas which has passed close to
the sliding surfaces between the drive shaft 7 and the lip seal 10
flows into the crank chamber 4 through the plain bearing 51, the
space 36 and the thrust bearing 12. The rest of the refrigerant gas
flows into the crank chamber 4 through the passages 34, 35. The
rest of the structure of the compressor of the second embodiment is
substantially the same as that of the compressor 1 of the first
embodiment. Thus, the compressor of the second embodiment using the
plain bearing 51 offers substantially the same effects as that of
the first embodiment.
[0039] Referring to FIG. 4, a part of the variable displacement
compressor of the third embodiment is shown. In the first
embodiment, the lug plate 11 is rotatably supported by the radial
roller bearing 8 inserted in the front housing 3. The third
embodiment differs from the first embodiment in that the radial
roller bearing 8 and the annular partition 21 are replaced by a
radial roller bearing 108 and an annular partition 121,
respectively.
[0040] The compressor of the third embodiment includes a front
housing 103 having a crank chamber 104. A drive shaft 107 is
disposed in the crank chamber 104 at the center of the front
housing 103. The front portion of the drive shaft 107 is rotatably
supported by the radial roller bearing 108 inserted in the front
housing 103. The rear portion of the drive shaft 107 is also
rotatably supported by the radial roller bearing 9 inserted in the
cylinder block 2. Thus, the drive shaft 107 is rotatably supported
by the radial roller bearings 108, 9 and serves as the rotary shaft
of the present invention. The drive shaft 107 has a slanted passage
133 as that of the first embodiment. A shaft seal chamber 122 is
formed in the front housing 103 by the front housing 103, the
small-diameter portion, the tapered portion and the large-diameter
portion of the drive shat 107, the radial roller bearing 108 and
the lip seal 10. An annular partition 121 having an L-shape section
is disposed between the lip seal 10 and the radial roller bearing
108 in the shaft seal chamber 122. The partition 121 is located so
as to cover the opening 133A of the slanted passage 133 that is
opened to the shaft seal chamber 122, and fixed to the outer
circumferential surface of the large-diameter portion of the drive
shaft 107 for rotation therewith. Thus, the shaft seal chamber 122
is partitioned into a first seal chamber 122A and a second seal
chamber 122B by the partition 121.
[0041] Clearance B is formed between the inner circumferential
surface 121A of the partition 121 and the outer circumferential
surface 107D of the small-diameter portion of the drive shaft 107
facing the inner circumferential surface 121A and serves as the
first guide passage of the present invention. Therefore, the
refrigerant gas flowed into the first seal chamber 122A through the
slanted passage 133 flows into the second seal chamber 122B through
the clearance B. The refrigerant gas flowed into the second seal
chamber 122B is substantially all supplied to the lip seal 10 along
the outer circumferential surface 107D of the small-diameter
portion of the drive shaft 107 and then passes close to the lip
seal 10. The rest of the structure of the compressor of the third
embodiment is substantially the same as that of the compressor 1 of
the first embodiment. Thus, the compressor of the third embodiment
wherein the drive shaft 107 is rotatably supported by the radial
roller bearing 108 inserted in the front housing 103 and the
partition 121 is fixed on the drive shaft 107 offers substantially
the same effects as that of the first embodiment.
[0042] Referring to FIG. 5, a part of the variable displacement
compressor of the fourth embodiment is shown. The compressor of the
fourth embodiment differs from that of the first embodiment in that
the annular partition 21 of the first embodiment is replaced by an
annular partition 221.
[0043] As shown in FIG. 5, the annular partition 221 is fixed to
the front end of the lug plate 11 for rotation therewith. Clearance
A is formed between the inner circumferential surface 221A of the
partition 221 and the outer circumferential surface 7D of the drive
shaft 7 facing the inner circumferential surface 221A. The
partition 221 has in the rear thereof a slanted inner
circumferential surface 221B that defines the first seal chamber
22A with the outer circumferential surface 7F of the tapered
portion of the drive shaft 7. The slanted inner circumferential
surface 221B is formed so that the inside diameter of the partition
221 decreases from the rear end of the partition 221 to the rear
end of the inner circumferential surface 221A. Thus, the first seal
chamber 22A is defined between the inner circumferential surface
221B of the partition 221 and the outer circumferential surface 7F
of the tapered portion of the drive shaft 7 so that its sectional
area decreases from a position adjacent to the opening 33A of the
slanted passage 33 toward the clearance A. Therefore, the flow of
refrigerant gas flowing into the first seal chamber 22A through the
slanted passage 33 is restricted in passing through the passage
formed between the inner circumferential surface 221B and the outer
circumferential surface 7F and the refrigerant gas is flowed into
the second seal chamber 22B through the clearance A at an increased
velocity. The rest of the structure of the compressor of the fourth
embodiment is substantially the same as that of the compressor 1 of
the first embodiment.
[0044] The refrigerant gas thus having increased its velocity is
supplied to the lip seal 10 and passes close to the lip seal 10.
Although the lip seal 10 is heated by the heat produced in the
sliding surfaces between the lip seal 10 and the drive shaft 7, the
amount of heat that is released from the lip seal 10 to refrigerant
gas is increased because the velocity of the refrigerant gas that
passes close to the lip seal 10 is increased. Therefore, heat
generation of the lip seal 10 is decreased thereby to further
enhance the reliability of the lip seal 10.
[0045] Referring to FIG. 6, a part of the variable displacement
compressor of the fifth embodiment is shown. The compressor of the
fifth embodiment differs from that of the first embodiment in that
the partition 21 of the first embodiment is replaced by an annular
partition 321.
[0046] As shown in FIG. 6, the annular partition 321 is fixed to
the front end of the lug plate 11 for rotation therewith. The
partition 321 serves to partition the shaft seal chamber 22 into
the first seal chamber 22A and the second seal chamber 22B and the
clearance A is formed between the partition 321 and the drive shaft
7 as in the first embodiment. The front end of the partition 321 is
formed so as to cover the tapered portion of the lip seal 10. The
partition 321 has a slanted inner circumferential surface 321C that
is substantially parallel to the outer circumferential surface 10B
of the tapered portion of the lip seal 10. Clearance C is formed
between the outer circumferential surface 10B of the tapered
portion of the lip seal 10 and the slanted inner circumferential
surface 321C of the partition 321 and serves as the second guide
passage of the present invention. Therefore, the refrigerant gas
flowed into the first seal chamber 22A through the slanted passage
33 then flows into the second seal chamber 22B through the
clearances A and C. Because the refrigerant gas flowed into the
clearance C is prevented from diffusing radially outward by the
slanted inner circumferential surface 321C of the partition 321,
substantially all the refrigerant gas flowed into the clearance C
passes close to the sliding surfaces between the drive shaft 7 and
the lip seal 10. The rest of the structure of the compressor of the
fourth embodiment is substantially the same as that of the
compressor 1 of the first embodiment.
[0047] Thus, providing the partition 321 with the clearance C
allowing the refrigerant gas flowed through the clearance A to flow
along the outer circumferential surface 10B of the lip seal 10, the
refrigerant gas supplied to the lip seal 10 through the clearance A
is substantially all prevented from diffusing radially outward by
the slanted inner circumferential surface 321C of the partition 321
and passes close to the sliding surfaces between the drive shaft 7
and the lip seal 10. Therefore, lubricating oil is supplied
positively to the sliding surfaces between the drive shaft 7 and
the lip seal 10.
[0048] Referring to FIG. 7, a part of the variable displacement
compressor of the sixth embodiment is shown. The compressor of the
sixth embodiment differs from that of the third embodiment in that
the partition 121 of the third embodiment is replaced by the
partition 321 of the fifth embodiment. In the following description
of the sixth embodiment, like reference numerals or symbols denote
the like elements or parts of the compressor used in the
description of the first and third embodiments and the detailed
description of such elements or parts will be omitted.
[0049] As shown in FIG. 7, an annular partition 421 is disposed
between the lip seal 10 and the radial roller bearing 108 in the
shaft seal chamber 122. The partition 421 is located so as to cover
the opening 133A of the slanted passage 133 and fixed to the outer
circumferential surface of the large-diameter portion of the drive
shaft 107 for rotation therewith. The partition 421 serves to
partition the shaft seal chamber 122 into the first seal chamber
122A and the second seal chamber 122B and the clearance D is formed
between the partition 421 and the drive shaft 107 as in the third
embodiment. The clearance D serves as the first guide passage of
the present invention. The front end of the partition 421 is formed
so as to cover the tapered portion of the lip seal 10 and has a
slanted inner circumferential surface 421C that is substantially
parallel to the outer circumferential surface 10B of the tapered
portion of the lip seal 10 as in the fifth embodiment. Clearance C
is formed between the outer circumferential surface 10B of the
tapered portion of the lip seal 10 and the slanted inner
circumferential surface 421C of the partition 421 and serves as the
second guide passage of the present invention. The rest of the
structure of the compressor of the sixth embodiment is
substantially the same as that of the compressor 1 of the first
embodiment.
[0050] Thus, the compressor of the sixth embodiment wherein the
partition 421 is fixed on the drive shaft 107 offers substantially
the same effects as that of the fifth embodiment.
[0051] Although in each of the first through sixth embodiments a
single slanted passage is formed in the drive shaft, a plurality of
such slanted passages may be formed in the drive shaft.
[0052] In the third through sixth embodiments, the radial roller
bearing may be replaced by the plain bearing 61 in the second
embodiment.
[0053] Although in each of the fifth and sixth embodiments the
partition covers the outer circumferential surface 10B of the
tapered portion of the lip seal 10, the region of the lip seal 10
to be covered by the partition is not limited to the tapered
portion but it may include the outer circumferential surface of the
lip seal 10 that is parallel to the axial direction of the drive
shaft.
[0054] In each of the fifth and sixth embodiments, the inner
circumferential surface of the partition that defines the first
seal chamber may be formed as in the fourth embodiment. That is,
the partition may be formed with the inside diameter thereof
decreased from the rear end of the partition to the clearance A or
D.
[0055] Although in each of the fifth and sixth embodiments the
inner circumferential surface of the partition that forms the
clearance C is substantially parallel to the outer circumferential
surface 10B of the tapered portion of the lip seal 10, the
positional relation between the inner circumferential surface of
the partition and the outer circumferential surface 10B of the lip
seal 10 is not limited to the parallel disposition. The inner
circumferential surface of the partition may be inclined in any way
as long as the surface prevents refrigerant gas from diffusing
radially outward.
* * * * *