U.S. patent application number 12/769047 was filed with the patent office on 2010-11-11 for fixed displacement piston compressor.
This patent application is currently assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. Invention is credited to Mitsuyo ISHIKAWA, Toshiyuki KOBAYASHI.
Application Number | 20100282070 12/769047 |
Document ID | / |
Family ID | 43061571 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100282070 |
Kind Code |
A1 |
ISHIKAWA; Mitsuyo ; et
al. |
November 11, 2010 |
FIXED DISPLACEMENT PISTON COMPRESSOR
Abstract
A compressor includes a rotary shaft, a swash plate, a cylinder
block, plural pistons, a crank chamber, a housing, plural passages,
a thrust bearing, and an anti-rotation mechanism. The crank chamber
accommodates therein the swash plate, and refrigerant of suction
pressure is introduced into the crank chamber. The housing is
connected to the cylinder block and forms therein a suction chamber
and a discharge chamber. The plural passages are provided for
communication between the crank chamber and the suction chamber.
The thrust bearing is provided between the swash plate and the
cylinder block so as to receive thrust load from the swash plate.
The thrust bearing has a thrust race located adjacent to the
cylinder block. The anti-rotation mechanism is provided for
preventing relative rotation of the thrust race to the cylinder
block. The anti-rotation mechanism restricts the fluid flow through
a specific passage of the plural passages.
Inventors: |
ISHIKAWA; Mitsuyo;
(Aichi-ken, JP) ; KOBAYASHI; Toshiyuki;
(Aichi-ken, JP) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Aichi-ken
JP
|
Family ID: |
43061571 |
Appl. No.: |
12/769047 |
Filed: |
April 28, 2010 |
Current U.S.
Class: |
91/499 |
Current CPC
Class: |
F04B 27/1063
20130101 |
Class at
Publication: |
91/499 |
International
Class: |
F01B 3/00 20060101
F01B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2009 |
JP |
2009-114169 |
Claims
1. A fixed displacement piston compressor, comprising: a rotary
shaft; a swash plate fixed to the rotary shaft; a cylinder block
supporting the rotary shaft, the cylinder block having plural
cylinder bores arranged around the rotary shaft; plural pistons
accommodated in the respective cylinder bores, the pistons being
coupled to the rotary shaft through the swash plate; a crank
chamber into which refrigerant of suction pressure is introduced,
the crank chamber accommodating therein the swash plate; a housing
connected to the cylinder block and forming therein a suction
chamber and a discharge chamber; plural passages for communication
between the crank chamber and the suction chamber; a thrust bearing
provided between the swash plate and the cylinder block so as to
receive thrust load from the swash plate, the thrust bearing having
a thrust race located adjacent to the cylinder block; and an
anti-rotation mechanism for preventing relative rotation of the
thrust race to the cylinder block, the anti-rotation mechanism
restricting the fluid flow through a specific passage of the plural
passages.
2. The fixed displacement piston compressor according to claim 1,
wherein the specific passage is one whose opening to the crank
chamber is located at the lowest position as viewed in vertical
direction when the compressor is installed in a vehicle.
3. The fixed displacement piston compressor according to claim 1,
further comprising an inlet port through which refrigerant of
suction pressure is introduced into the crank chamber, wherein the
specific passage is one whose opening to the crank chamber is
located closest to the inlet port.
4. The fixed displacement piston compressor according to claim 1,
wherein each passage is formed in the cylinder block, and the
opening of each passage to the crank chamber is located around the
thrust race.
5. The fixed displacement piston compressor according to claim 4,
wherein the anti-rotation mechanism includes a projection formed in
the periphery of the thrust race so as to extend radially outward
and a retainer formed in the cylinder block so as to restrict
movement of the projection, and the projection is located at a
position over the opening of the specific passage.
6. The fixed displacement piston compressor according to claim 5,
wherein there is provided a gap between the opening of the specific
passage and the projection.
7. The fixed displacement piston compressor according to claim 5,
wherein a pair of the retainers is formed in the cylinder block so
as to project toward the swash plate, and the retainers are located
on opposite sides of the projection as viewed in rotating direction
of the rotary shaft so that the projection is brought into contact
with the retainers.
8. The fixed displacement piston compressor according to claim 4,
wherein the anti-rotation mechanism includes a projection formed in
the periphery of the thrust race so as to extend radially outward
and a pin mounted to the projection, the pin being inserted in the
opening of the specific passage.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a fixed displacement piston
compressor having a swash plate in a crank chamber from which
refrigerant to be compressed is delivered to a suction chamber
through plural passages.
[0002] A fixed displacement piston compressor having such plural
passages for communication between the crank chamber and the
suction chamber and a thrust bearing is known. The thrust bearing
is provided between the swash plate and the cylinder block and has
a thrust race on the side adjacent to the cylinder block. In such
compressor, since the rotation of the thrust race relative to the
cylinder block causes wear of the cylinder block due to sliding
contact therebetween, it is required to prevent such relative
rotation of the thrust race of the thrust bearing to the cylinder
block. Additionally, the function of some specific passages among
the plural passages is restricted as needed, for example, in order
to increase the amount of lubricating oil to be stored in the crank
chamber and also to equalize the compression in the respective
compression chambers.
[0003] A compressor disclosed in Japanese Unexamined Utility Model
Application Publication No. 7-10474 has a mechanism for preventing
such relative rotation of the thrust race of the thrust bearing to
the cylinder block. The compressor has a swash plate inclined to
and rotatable around the axis of the rotary shaft of the
compressor, a piston disposed at a position spaced radially from
the axis of the rotary shaft and reciprocable along the axis with
the rotation of the swash plate, and a cylinder block accommodating
therein the piston. A thrust bearing is provided between the
cylinder block and the swash plate. The thrust race of the thrust
bearing adjacent to the cylinder block has a recess, while the
cylinder block has a projection engageable with the recess. The
engagement of the recess with the projection prevents relative
rotation of the thrust race to the cylinder block, thereby
preventing wear between thrust race and the cylinder block.
[0004] Japanese Unexamined Patent Application Publication No.
2000-297745 discloses another compressor in which the function of
some specific passages of the plural passages for delivering
refrigerant from the crank chamber to the suction chamber is
restricted. In such compressor wherein the suction chamber, from
which refrigerant is delivered to plural compression chambers, is
connected through the crank chamber to an inlet port that is
further connected to an evaporator in an external refrigerant
circuit of the compressor, refrigerant is introduced from the inlet
port through the crank chamber into the suction chamber. Of the
plural passages for delivering refrigerant from the crank chamber
to the suction chamber, the passage opened to the crank chamber at
a position above the rotary shaft has a flow resistance that is
smaller than that of the passage opened to the crank chamber at a
position below the rotary shaft. In this case, the amount of
refrigerant flowing into the suction chamber through the upper
passage is larger than that flowing through the lower passage,
which prevents large amount of liquid refrigerant from flowing into
the suction chamber.
[0005] In the compressor disclosed in Japanese Unexamined Utility
Model Application Publication No. 7-10474, however, the recess and
the projection in the thrust race of the thrust bearing and the
cylinder block, respectively, are provided merely to prevent
relative rotation of the thrust race to the cylinder block. On the
other hand, in the compressor disclosed in Japanese Unexamined
Patent Application Publication No. 2000-297745, a part of the
compressor serving as a throttle for restricting the function of
the passage is provided merely to offer the same effect as
decreasing the diameter of the passage.
[0006] The present invention is directed to providing a fixed
displacement piston compressor that prevents relative rotation of a
thrust race of a thrust bearing to a cylinder block and also
restricts the function of a specific passage.
SUMMARY OF THE INVENTION
[0007] In accordance with an aspect of the present invention, a
fixed displacement piston compressor includes a rotary shaft, a
swash plate, a cylinder block, plural pistons, a crank chamber, a
housing, plural passages, a thrust bearing, and an anti-rotation
mechanism. The swash plate is fixed to the rotary shaft. The
cylinder block supports the rotary shaft and has plural cylinder
bores arranged around the rotary shaft. The plural pistons are
accommodated in the respective cylinder bores. The pistons are
coupled to the rotary shaft through the swash plate. The crank
chamber accommodates therein the swash plate, and refrigerant of
suction pressure is introduced into the crank chamber. The housing
is connected to the cylinder block and forms therein a suction
chamber and a discharge chamber. The plural passages are provided
for communication between the crank chamber and the suction
chamber. The thrust bearing is provided between the swash plate and
the cylinder block so as to receive thrust load from the swash
plate. The thrust bearing has a thrust race located adjacent to the
cylinder block. The anti-rotation mechanism is provided for
preventing relative rotation of the thrust race to the cylinder
block. The anti-rotation mechanism restricts the fluid flow through
a specific passage of the plural passages.
[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] FIG. 1 is a longitudinal sectional view of a fixed
displacement piston compressor according to a first embodiment of
the present invention;
[0010] FIG. 2A is a cross-sectional view taken along the line
IIA-IIA of FIG. 1, showing a thrust race of a thrust bearing of the
compressor of FIG. 1;
[0011] FIG. 2B is similar to FIG. 2A, but showing the cross section
of the compressor with the thrust race removed;
[0012] FIG. 3A is a cross-sectional view taken along the line
IIIA-IIIA of FIG. 1, showing a thrust race of another thrust
bearing of the compressor of FIG. 1;
[0013] FIG. 3B is similar to FIG. 3A, but showing the cross section
of the compressor with the thrust race removed;
[0014] FIG. 4A is a fragmentary sectional view of a fixed
displacement piston compressor according to a second embodiment of
the present invention; and
[0015] FIG. 4B is a front view of a thrust race of a thrust bearing
of the compressor of FIG. 4A as viewed from the swash plate of FIG.
4A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] FIG. 1 shows a fixed-displacement piston compressor
according to the first embodiment of the present invention. It is
noted that the left-hand side and the right-hand side as viewed in
FIG. 1 are the front side and the rear side of the compressor,
respectively, and that the upper and lower sides as viewed in FIG.
1 are the upper and lower sides of the compressor when installed in
place, respectively.
[0017] The compressor has a pair of cylinder blocks 11 and 12 that
are connected to front and rear housings 13 and 16, respectively.
The front housing 13 and the rear housing 16 are fastened to the
cylinder blocks 11 and 12 using plural bolts 19 (only one is shown
in FIG. 1) each of which has an externally threaded end 19A. Each
bolt 19 is inserted through bolt holes 13A, 11A and 12A formed in
the front housing 13, the cylinder blocks 11 and 12, respectively,
so that the threaded end 19A is screwed into a threaded hole 16A
formed in the rear housing 16.
[0018] The front housing 13 forms therein a discharge chamber 14
and a suction chamber 15, and the rear housing 16 forms therein a
discharge chamber 17 and a suction chamber 18. The compressor has a
valve port plate 20, a valve plate 22 and a retainer plate 24
interposed between the cylinder block 11 and the front housing 13.
The compressor further has a valve port plate 26, a valve plate 28
and a retainer plate 30 interposed between the cylinder block 12
and the rear housing 16.
[0019] The valve port plates 20 and 26 are formed with discharge
ports 21 and 27, respectively. The valve plates 22 and 28 are
formed with discharge valves 23 and 29 that close the discharge
ports 21 and 27, respectively. The retainer plates 24 and 30 are
formed with retainers 25 and 31 that regulate the opening of the
discharge valves 23 and 29, respectively.
[0020] The cylinder blocks 11 and 12 are formed therethrough with
shaft holes 34 and 35, respectively, and a rotary shaft 32 is
inserted through the shaft holes 34 and 35 and rotatably supported
by the cylinder blocks 11 and 12. A seal member 33 is interposed
between the front housing 13 and the rotary shaft 32. The front
housing 13, the rotary shaft 32 and the seal member 33 cooperate to
define a space 48 that is connected to the suction chamber 15
through a passage 13B. The compressor has a swash plate 36 fixed on
the rotary shaft 32 for rotation therewith. The swash plate 36 is
accommodated in a crank chamber 37 that is formed by and between
the cylinder blocks 11 and 12.
[0021] A thrust bearing 46 is disposed between an annular base 36A
of the swash plate 36 and the end surface 11 B of the cylinder
block 11, and a thrust bearing 47 is disposed between the base 36A
of the swash plate 36 and the end surface 12B of the cylinder block
12.
[0022] The cylinder block 11 is formed with an inlet port 38
through which the crank chamber 37 communicates with an external
refrigerant circuit (not shown). The cylinder block 11 is formed
therethrough with plural passages 39 (see FIGS. 2A and 2B) that
connect the crank chamber 37 to the suction chamber 15 of the front
housing 13, and similarly the cylinder block 12 is formed
therethrough with plural passages 49 (see FIGS. 3A and 3B) that
connect the crank chamber 37 to the suction chamber 18 of the rear
housing 16.
[0023] Referring to FIGS. 2A, 2B, 3A and 3B, the cylinder block 11
is formed with plural cylinder bores 40 arranged around the rotary
shaft 32, and the cylinder block 12 is formed similarly with plural
cylinder bores 50 arranged around the rotary shaft 32. Each
cylinder bore 40 is paired with its opposite cylinder bore 50 to
accommodate therein a double-headed piston 44. The front end of the
double-headed piston 44 defines a compression chamber 41 in the
cylinder bore 40, and the rear end of the double-headed piston 44
defines a compression chamber 51 in the cylinder bore 50. The swash
plate 36 has a pair of shoes 45 for each piston 44 for transmitting
the rotating motion of the swash plate 36 to the piston 44.
[0024] A part of the inner peripheral surface of the shaft hole 34
which is in contact with the rotary shaft 32 serves as a sealing
surface 42, and a part of the inner peripheral surface of the shaft
hole 35 which is in contact with the rotary shaft 32 also serves as
a sealing surface 52. The diameter of circles described by the
sealing surfaces 42 and 52 of the shaft holes 34 and 35 is smaller
than that of other parts of the shaft holes 34 and 35. Therefore,
the rotary shaft 32 is supported directly on the sealing surfaces
42 and 52 of the cylinder blocks 11 and 12.
[0025] A supply passage 54 is formed in the rotary shaft 32 so as
to extend in the longitudinal direction of the compressor. The
supply passage 54 is opened at the rear end of the rotary shaft 32
to the suction chamber 18 in the rear housing 16. The rotary shaft
32 is formed with passages 55 and 56 that communicate with the
supply passage 54.
[0026] The cylinder block 11 is formed with plural passages 43
(only one is shown in FIG. 1) that are communicable with their
associated cylinder bores 40 and the shaft hole 34. The passage 43
has an inlet 43A that is opened on the sealing surface 42 and
intermittently communicable with the outlet 55A of the passage 55
as the rotary shaft 32 rotates.
[0027] The cylinder block 12 is formed with plural passages 53
(only one is shown in FIG. 1) that are communicable with their
associated cylinder bores 50 and the shaft hole 35. The passage 53
has an inlet 53A that is opened on the sealing surface 52 and
intermittently communicable with the outlet 56A of the passage 56
as the rotary shaft 32 rotates.
[0028] A part of the rotary shaft 32 that is surrounded by the
sealing surfaces 42 and 52 serves as a rotary valve. The rotary
shaft 32 has ports 57 and 58 in the periphery thereof. The ports 57
and 58 are radially aligned with passages 60 and 61, respectively,
which are formed through the base 36A of the swash plate 36. The
supply passage 54 of the rotary shaft 32 communicates with the
crank chamber 37 through the ports 57 and 58 and the passages 60
and 61. The rotary shaft 32 is formed with a passage 59 that
connects the supply passage 54 to the space 48.
[0029] The thrust bearing 46 has a ring-shaped thrust race 62
adjacent to the base 36A of the swash plate 36, a ring-shaped
thrust race 63 adjacent to the end surface 11B of the cylinder
block 11 and a plurality of cylindrical rollers 64 provided between
the thrust races 62 and 63. The thrust bearing 47 has a ring-shaped
thrust race 65 adjacent to the base 36A of the swash plate 36, a
ring-shaped thrust race 66 adjacent to the end surface 128 of the
cylinder block 12 and a plurality of cylindrical rollers 67
provided between the thrust races 65 and 66.
[0030] In the present embodiment, as shown in FIGS. 2A and 3A, the
compressor has anti-rotation mechanisms 70 and 71 for preventing
the thrust race 63 of the thrust bearing 46 from rotating relative
to the cylinder block 11, and anti-rotation mechanisms 80 and 81
for preventing the thrust race 66 of the thrust bearing 47 from
rotating relative to the cylinder block 12.
[0031] FIG. 2A shows the thrust race 63 of the thrust bearing 46
adjacent to the cylinder block 11, and FIG. 2B is similar to FIG.
2A with the thrust race 63 removed from the cylinder block 11. In
the drawings, the double-headed pistons 44 are not illustrated for
simplification. As shown in the drawings, the opening of each
passage 39 to the crank chamber 37 is located around the thrust
race 63, and the thrust race 63 has two projections 72 and 73
formed in the periphery thereof so as to extend radially outward
over the openings of the specific passages 39 of the plural
passages 39. The projection 72 restricts the fluid flow through the
passage 39 that is closest to the inlet port 38 of the plural
passages 39. The projection 73 restricts the fluid flow through the
passage 39 whose position is lowest of the plural passages 39 when
the compressor is installed in place in a vehicle (the passage 39
whose position is lowest in FIG. 2). Specifically, the specific
passage 39 associated with the projection 73 is one whose opening
to the crank chamber 37 is located at the lowest position as viewed
in vertical direction when the compressor is installed in a
vehicle, and the specific passage 39 associated with the projection
72 is one whose opening to the crank chamber 37 is located closest
to the inlet port 38. There is provided a gap between the opening
of the specific passage 39 and the projection 72 (73) of the thrust
race 63 of the thrust bearing 46 (see FIG. 1).
[0032] The cylinder block 11 has a pair of retainers 74 and a pair
of retainers 75 projecting from the end surface 11B of the cylinder
block 11 toward the swash plate 36. The retainers 74 are located on
opposite sides of the projection 72 as viewed in the rotating
direction of the rotary shaft 32, and similarly the retainers 75
are located on opposite sides of the projection 73 as viewed in the
rotating direction of the rotary shaft 32. The movement of the
projections 72 and 73 in the rotating direction of the rotary shaft
32 is prevented by the retainers 74 and 75, so that the rotation of
the thrust race 63 on the axis P of the rotary shaft 32 is
restricted. The projections 72 and 73 cooperate with their
associated retainers 74 and 75 to serve as the anti-rotation
mechanism 70 and 71, respectively.
[0033] FIG. 3A shows the thrust race 66 of the thrust bearing 47
adjacent to the cylinder block 12, and FIG. 3B is similar to FIG.
3A with the thrust race 66 removed from the cylinder block 12. In
the drawings, the double-headed pistons 44 are not illustrated for
simplification. As shown in the drawings, the opening of each
passage 49 to the crank chamber 37 is located around the thrust
race 66, and the thrust race 66 has two projections 82 and 83
formed in the periphery thereof so as to extend radially outward
over the openings of the specific passages 49 of the plural
passages 49. The projection 82 restricts the fluid flow through the
passage 49 that is closest to the inlet port 38 of the plural
passages 49. The projection 83 restricts the fluid flow through the
passage 49 whose position is lowest of the plural passages 49 when
the compressor is installed in place in a vehicle (the passage 49
whose position is lowest in FIG. 3). Specifically, the specific
passage 49 associated with the projection 83 is one whose opening
to the crank chamber 37 is located at the lowest position as viewed
in vertical direction when the compressor is installed in a
vehicle, and the specific passage 49 associated with the projection
82 is one whose opening to the crank chamber 37 is located closest
to the inlet port 38. There is provided a gap between the opening
of the specific passage 49 and the projection 82 (83) of the thrust
race 66 of the thrust bearing 47 (see FIG. 1).
[0034] The cylinder block 12 has a pair of retainers 84 and a pair
of retainers 85 projecting from the end surface 12B of the cylinder
block 12 toward the swash plate 36. The retainers 84 are located on
opposite sides of the projection 82 as viewed in the rotating
direction of the rotary shaft 32, and similarly the retainers 85
are located on opposite sides of the projection 83 as viewed in the
rotating direction of the rotary shaft 32. The movement of the
projections 82 and 83 in the rotating direction of the rotary shaft
32 is prevented by the retainers 84 and 85, so that the rotation of
the thrust race 66 on the axis P of the rotary shaft 32 is
restricted. The projections 82 and 83 cooperate with their
associated retainers 84 and 85 to serve as the anti-rotation
mechanism 80 and 81, respectively.
[0035] In the above-described compressor, when the rotary shaft 32
is rotated with the swash plate 36 by the driving force from a
drive source not shown, the rotating motion of the swash plate 36
is transmitted to the double-headed pistons 44 through the shoes
45, so that each double-headed piston 44 reciprocates in its
associated cylinder bores 40 and 50. Refrigerant of suction
pressure is introduced from the external refrigerant circuit
through the inlet port 38 into the crank camber 37 and then flows
through the passages 60 and 61 and the ports 57 and 58 into the
supply passage 54. Part of the refrigerant introduced into the
crank chamber 37 is delivered through the passages 39 and 49 to the
suction chambers 15 and 18. The refrigerant in the suction chamber
15 is introduced through the passage 13B, the space 48 and the
passage 59 into the supply passage 54. The refrigerant in the
suction chamber 18 is introduced directly into the supply passage
54.
[0036] When the double-headed piston 44 is in the suction stroke
for the cylinder bore 40, that is, when the double-headed piston 44
is moving rightward in FIG. 1, the outlet 55A of the passage 55 is
connected to the inlet 43A of the passage 43. Refrigerant in the
passage 54 of the rotary shaft 32 is introduced through the
passages 55 and 43 into the compression chamber 41 in the cylinder
bore 40.
[0037] When the double-headed piston 44 is in the discharge stroke
for the first cylinder bore 40, that is, when the double-headed
piston 44 is moving leftward in FIG. 1, the outlet 55A of the
passage 55 is disconnected from the inlet 43A of the passage 43.
Refrigerant in the compression chamber 41 is discharged into the
discharge chamber 14 through the discharge port 21 while pushing
open the discharge valve 23. The refrigerant discharged into the
discharge chamber 14 then flows into the external refrigerant
circuit. The refrigerant flowed through the external refrigerant
circuit then returns through the inlet port 38 to the crank chamber
37.
[0038] When the double-headed piston 44 is in the suction stroke
for the cylinder bore 50, that is, when the double-headed piston 44
is moving leftward in FIG. 1, the outlet 56A of the passage 56 is
connected to the inlet 53A of the passage 53. Refrigerant in the
passage 54 of the rotary shaft 32 is introduced through the
passages 56 and 53 into the compression chamber 51 in the cylinder
bore 50.
[0039] When the double-headed piston 44 is in the discharge stroke
for the cylinder bore 50, that is, when the double-headed piston 44
is moving rightward in FIG. 1, the outlet 56A of the passage 56 is
disconnected from the inlet 53A of the passage 53. Refrigerant in
the compression chamber 51 is discharged into the discharge chamber
17 through the discharge port 27 while pushing open the discharge
valve 29. The refrigerant discharged into the discharge chamber 17
flows into the external refrigerant circuit. The refrigerant flowed
through the external refrigerant circuit then returns through the
inlet port 38 to the crank chamber 37.
[0040] While the compressor is in operation and the swash plate 36
is rotating with the rotary shaft 32, the thrust bearings 46 and 47
support the thrust load from the swash plate 36. In this case,
although the thrust race 63 of the thrust bearing 46 not only
supports the thrust load but also receives a force acting in the
rotating direction of the rotary shaft 32, the projections 72 and
73 of the thrust race 63 are brought into contact with the
retainers 74 and 75, respectively, thereby restricting the rotation
of the thrust race 63. Thus, the anti-rotation mechanisms 70 and 71
prevent the thrust race 63 of the thrust bearing 46 from rotating
relative to the cylinder block 11.
[0041] Flow of refrigerant through the passage 39 that is closest
to the inlet port 38 is restricted the projection 72 of the thrust
race 63, so that the function of such passage 39 is restricted.
This prevents the refrigerant introduced through the inlet port 38
into the crank chamber 37 from flowing concentratedly through the
passage 39 that is closest to the inlet port 38, so that the amount
of the refrigerant flowing through the passages 39 is made uniform.
On the other hand, the flow through the passage 39 whose position
is lowest is restricted by the projection 73 of the thrust race 63,
so that the function of such passage 39 is restricted. This makes
it difficult for the lubricating oil stored in the crank chamber 37
to flow through such passage 39 into the suction chamber 15.
[0042] Similarly, although the thrust race 66 of the thrust bearing
47 not only supports the thrust load but also receives a force
acting in the rotating direction of the rotary shaft 32, the
projections 82 and 83 of the thrust race 66 are brought into
contact with the retainers 84 and 85, respectively, thereby
restricting the rotation of the thrust race 66. Thus, the
anti-rotation mechanisms 80 and 81 prevent the thrust race 66 of
the thrust bearing 47 from rotating relative to the cylinder block
12.
[0043] Flow of refrigerant through the passage 49 that is closest
to the inlet port 38 is restricted the projection 82 of the thrust
race 66, so that the function of such passage 49 is restricted.
This prevents the refrigerant introduced through the inlet port 38
into the crank chamber 37 from flowing concentratedly through the
passage 49 that is closest to the inlet port 38, so that the amount
of the refrigerant flowing through the passages 49 is made uniform.
On the other hand, the flow through the passage 49 whose position
is lowest is restricted by the projection 83 of the thrust race 66,
so that the function of such passage 49 is restricted. This makes
it difficult for the lubricating oil stored in the crank chamber 37
to flow through such passage 49 into the suction chamber 18.
[0044] The compressor according to the first embodiment offers the
following advantages. [0045] (1) The anti-rotation mechanisms 70,
71, 80, 81 not only prevent the thrust races 63, 66 of the thrust
bearings 46, 47 adjacent to the cylinder blocks 11, 12 from
rotating relative to the cylinder blocks 11, 12, but also restrict
the fluid flow through the specific passages 39, 49 of the plural
passages 39, 49. This prevents wear due to the relative rotation of
the thrust races 63, 66 to the cylinder blocks 11, 12, as well as
preventing the reduction of the performance of the compressor or
refrigeration cycle by restricting the function of the specific
passages 39, 49. [0046] (2) The amount of the refrigerant flowing
through the passages 39, 49 closest to the inlet port 38 tends to
be larger than that flowing through the other passages 39, 49
located further away from the inlet port 38. Flow through the
passages 39, 49 closest to the inlet port 38 is restricted by the
anti-rotation mechanisms 70, 71, 80, 81. Thus, the amount of
refrigerant flowing through the plural passages 39, 49 is made
uniform, resulting in a smaller difference in efficiency of
compression among the respective cylinder bores. [0047] (3) Since
the anti-rotation mechanisms 70, 71, 80, 81 restrict the fluid flow
through the passages 39, 49 whose position is lowest as viewed in
the vertical direction, lubricating oil stored in the lower region
of the crank chamber 37 is restricted from flowing through such
passages 39, 49. Thus, the amount of lubricating oil to be stored
in the crank chamber 37 is increased, resulting in reduced amount
of lubricating oil flowing into the external refrigerant circuit
and also preventing reduction of efficiency of heat exchanging in
the refrigeration cycle. [0048] (4) The projections 72, 73, 82, 83
of the thrust races 63, 66, which serve to restrict the fluid flow
through the specific passages 39, 49, are restricted from moving by
the retainers 74, 75, 84, 85 of the cylinder blocks 11, 12, so that
relative rotation of the thrust races 63, 66 to the cylinder blocks
11, 12 is prevented. The prevention of the relative rotation of the
thrust races 63, 66 to the cylinder blocks 11, 12 may be
accomplished only by providing such simple projections 72, 73, 82,
83 on the thrust races 63, 66 and the retainers 74, 75, 84, 85 on
the cylinder blocks 11, 12. The projections 72, 73, 82, 83 restrict
the fluid flow through the specific passages 39, 49 to restrict the
function of such passages 39, 49.
[0049] FIGS. 4A and 4B show the second embodiment of the present
invention. The second embodiment differs from the first embodiment
in the structure of the anti-rotation mechanism. In the drawings,
same reference numerals are used for the common elements or
components in the first and second embodiments, and the description
of such elements or components for the second embodiment will be
omitted.
[0050] As shown in FIGS. 4A and 4B, the anti-rotation mechanism 90
is provided by a projection 92, a pin 94 and the passage 39. The
projection 92 is formed in the periphery of the thrust race 91
adjacent to the cylinder block 11 so as to project radially
outward. The projection 92 is formed therethrough with a hole 93 in
which the pin 94 is mounted by press fitting. The diameter of the
pin 94 is set so that the pin 94 is inserted in the opening of the
passage 39. The thrust bearing is positioned so that its thrust
race 91 faces the end surface 11B of the cylinder block 11 with the
pin 94 inserted in the opening of the passage 39 whose position is
lowest.
[0051] With the anti-rotation mechanism 90 of the second
embodiment, although force is applied to the thrust race 91 in the
rotating direction of the rotary shaft 32 while the compressor is
operating, the pin 94 inserted in the opening of the passage 39
restricts the movement of the projection 92 of the thrust race 91,
so that the rotation of the thrust race 91 on the axis P is
prevented. The pin 94 inserted in the opening of the specific
passage 39 whose position is lowest restricts the fluid flow
through such passage 39 and the function thereof. In the second
embodiment, the pin 94 may be inserted not in the opening of the
passage 39 at the lowest position, but in the opening of the
passage 39 closest to the inlet port 38. Alternatively, the thrust
race 91 may have two projections each having a pin, such as the
projection 92 and the pin 94, so that one of the pins is inserted
in the opening of the passage 39 whose position is lowest and the
other pin is inserted in the opening of the passage 39 closest to
the inlet port 38. Further, an anti-rotation mechanism such as the
anti-rotation mechanism 90 may be provided for the thrust race of
the thrust bearing adjacent to the cylinder block 12.
[0052] According to the second embodiment, the end surfaces 11B,
12B of the cylinder blocks 11, 12 do not require projections such
as the retainers 74, 75, 84, 85 in the first embodiment, and the
opening of the passages 39, 49 in which the pin 94 is inserted may
be freely selected. Thus, even when the position of the compressor
around the axis P of the rotary shaft 32 is changed, for example,
when the lowermost passages 39, 49 are changed depending on the
type of vehicles, the fluid flow through the passages 39, 49
located at the lowest position is restricted regardless of the type
of vehicles.
[0053] The above embodiments may be modified in various ways as
exemplified below.
[0054] Although in the first embodiment the anti-rotation mechanism
restricts the flow through the passage closest to the inlet port
and also through the passage whose position is lowest, either one
of these two passages may be restricted. The inlet port for
introducing refrigerant into the crank chamber may be provided on
any side of the cylinder block other than the bottom. The first
embodiment of the anti-rotation mechanism may be combined with the
second embodiment of the anti-rotation mechanism to restrict the
flow through the plural passages.
[0055] Although in the first embodiment the projection of the
thrust race restricts the flow through the passage, it may close
the passage so that no refrigerant flow is allowed. Although in the
first embodiment there is provided a gap between the projection of
the thrust race and the opening of the specific passage, the size
of the gap may be changed depending on the direction or degree of
the thrust load so that the projection serves as a variable
throttle.
[0056] Although in the second embodiment the thrust race is
provided separately from the pin, they may be provided integrally,
which results in reduced number of parts of the compressor.
Further, the cross section of the pin may be of any shape as far as
the pin serves to restrict the flow through the passage. The shape
includes, for example, a circle, a polygon and a semicircle.
[0057] Although in the first and second embodiments the present
invention is applied to a compressor having a rotary shaft serving
also as a rotary valve, it may be applied to a compressor having a
valve port plate formed with a suction port closed by a suction
valve. In this case, the passage connecting the crank chamber to
the suction chamber serves as a main passage for delivering
refrigerant to be compressed.
* * * * *