U.S. patent application number 10/721327 was filed with the patent office on 2004-06-03 for compressor in which heat transfer in a cylinder head is controlled.
Invention is credited to Iizuka, Jiro, Yamamoto, Kiyokazu.
Application Number | 20040105762 10/721327 |
Document ID | / |
Family ID | 32376156 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040105762 |
Kind Code |
A1 |
Iizuka, Jiro ; et
al. |
June 3, 2004 |
Compressor in which heat transfer in a cylinder head is
controlled
Abstract
In a compressor having a cylinder head defining a refrigerant
suction chamber and a refrigerant discharge chamber, the cylinder
head is provided with a space located between the refrigerant
suction chamber and the refrigerant discharge chamber. The cylinder
head is disposed at one end of a compressor housing so that each of
the refrigerant suction chamber and the refrigerant discharge
chamber communicates with a plurality of cylinder bores disposed
within the compressor housing and spaced from one another in a
circumferential direction. In each cylinder bore, a piston
reciprocally movable is disposed.
Inventors: |
Iizuka, Jiro; (Isesaki-shi,
JP) ; Yamamoto, Kiyokazu; (Isesaki-shi, JP) |
Correspondence
Address: |
BAKER BOTTS LLP
C/O INTELLECTUAL PROPERTY DEPARTMENT
THE WARNER, SUITE 1300
1299 PENNSYLVANIA AVE, NW
WASHINGTON
DC
20004-2400
US
|
Family ID: |
32376156 |
Appl. No.: |
10/721327 |
Filed: |
November 26, 2003 |
Current U.S.
Class: |
417/269 |
Current CPC
Class: |
F04B 27/1045
20130101 |
Class at
Publication: |
417/269 |
International
Class: |
F04B 001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 2002 |
JP |
2002/350215 |
Claims
What is claimed is:
1. A compressor comprising: a compressor housing; a plurality of
cylinder bores made in the compressor housing and spaced from one
another in a circumferential direction of the compressor; a
plurality of pistons reciprocally movable in the cylinder bores,
respectively; and a cylinder head opposite to one end of the
compressor housing and defining a refrigerant suction chamber and a
refrigerant discharge chamber each of which communicates with the
cylinder bores, the cylinder head having a space located between
the refrigerant suction chamber and the refrigerant discharge
chamber.
2. The compressor according to claim 1, wherein the space is formed
by a groove which opens to the outside of the cylinder head.
3. The compressor according to claim 1, wherein the refrigerant
suction chamber is at a radially center area of the cylinder head
while the refrigerant discharge chamber is at a radially outer
peripheral area of the cylinder head.
4. The compressor according to claim 3, wherein the refrigerant
discharge chamber has an annular shape.
5. The compressor according to claim 1, wherein the cylinder head
includes: a part defining the refrigerant discharge chamber; and a
heat-release protrusion formed on an outer surface of the part.
6. The compressor according to claim 1, wherein the cylinder head
has a refrigerant path for establishing communication between the
refrigerant suction chamber and the space, the space being tightly
sealed with respect to the outside of the cylinder head.
7. The compressor according to claim 6, wherein the refrigerant
path is defined by a hole formed in the cylinder head.
8. The compressor according to claim 6, wherein the refrigerant
path is defined by a groove formed in the cylinder head.
9. The compressor according to claim 1, wherein the space is
divided in a circumferential direction of the cylinder head into a
plurality of small spaces, the cylinder head having a reinforcing
part formed between every adjacent ones of the small spaces and
extending towards both the refrigerant suction chamber and the
refrigerant discharge chamber.
10. The compressor according to claim 1, further comprising a valve
plate interposed between the compressor housing and the cylinder
head.
11. The compressor according to any one of claims 1 to 10, wherein
a carbon dioxide refrigerant is used as a refrigerant.
Description
[0001] The present application claims priority to prior Japanese
application JP 2002-350215, the disclosure of which is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a compressor for use in, for
example, a refrigerating circuit of an automotive air
conditioner.
[0003] A compressor of the type comprises a compressor housing
having a cylinder bore, a cylinder head defining a refrigerant
suction chamber and a refrigerant discharge chamber each of which
is communicable with the cylinder bore, a piston inserted into the
cylinder bore, and a driving mechanism for driving reciprocal
motion of the piston. When the piston reciprocally moves in the
cylinder bore, a refrigerant travels from the refrigerant suction
chamber through the cylinder bore to the refrigerant discharge
chamber. Generally, the cylinder head is made of a good heat
conductor, such as aluminum. As the refrigerant, a carbon dioxide
refrigerant as an inert gas is preferably used in view of
environment protection.
[0004] However, in case where the carbon dioxide refrigerant is
used, a working pressure is about ten times greater than that of a
chlorofluorocarbon refrigerant. Therefore, it is necessary to
improve the durability of the compressor by using high-strength
materials for various parts of the compressor and/or by increasing
the thickness of the compressor housing. For example, it is
necessary to design the compressor so as to withstand an explosion
pressure up to 30 MPa at a discharge temperature of about
160-170.degree. C.
[0005] Further, in case where the carbon dioxide refrigerant is
used, the refrigerant at a temperature of about 30-40.degree. C.
flows into the refrigerant suction chamber. On the other hand, the
refrigerant within the refrigerant discharge chamber has a
temperature of about 80-170.degree. C. Thus, the difference in
temperature between the refrigerant suction chamber and the
refrigerant discharge chamber is great. The cylinder head defining
the refrigerant suction chamber and the refrigerant discharge
chamber is made of a heat conductor so that the heat of such a
high-temperature refrigerant within the refrigerant discharge
chamber is easily transmitted to the refrigerant suction chamber.
Accordingly, the temperature of the refrigerant in the suction
chamber is elevated and the density of the gaseous refrigerant in
the refrigerant suction chamber is decreased. This brings about a
reduction in mass flow rate of the refrigerant, leading to a
decrease in compression efficiency. As a result, the refrigerating
ability is lowered. If the compressor is used in the automotive air
conditioner, fuel consumption is increased.
[0006] In view of the above, Japanese Patent Application
Publication 2001-515174 (JP 2001-515174 A) discloses a compressor
in which each of a refrigerant suction chamber and a refrigerant
discharge chamber has an inner surface covered with an insulator.
With this structure, heat transfer between the refrigerant suction
chamber and the refrigerant discharge chamber is suppressed.
However, in case where heat insulation is realized by the use of an
additional element such as the insulator, the number of parts and
the number of assembling steps are increased. This results in a
decrease in productivity and an increase in cost.
SUMMARY OF THE INVENTION
[0007] It is therefore an object of this invention to provide a
compressor capable of reliably preventing temperature elevation of
a suction-side refrigerant due to heat transfer from a refrigerant
discharge chamber without using an additional element, such as an
insulator.
[0008] According to an aspect of this invention, there is provided
a compressor comprising a compressor housing, a plurality of
cylinder bores made in the compressor housing and spaced from one
another in a circumferential direction of the compressor, a
plurality of pistons reciprocally movable in the cylinder bores,
respectively, and a cylinder head opposite to one end of the
compressor housing and defining a refrigerant suction chamber and a
refrigerant discharge chamber each of which communicates with the
cylinder bores, the cylinder head having a space located between
the refrigerant suction chamber and the refrigerant discharge
chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a vertical sectional view of a compressor
according to a first embodiment of this invention;
[0010] FIG. 2 is a front view of a cylinder head used in the
compressor illustrated in FIG. 1;
[0011] FIG. 3 is a rear view of the cylinder head illustrated in
FIG. 2;
[0012] FIG. 4 is a vertical sectional view of a compressor
according to a second embodiment of this invention;
[0013] FIG. 5 is a rear view of a cylinder head used in the
compressor illustrated in FIG. 4;
[0014] FIG. 6 is a vertical sectional view of a compressor
according to a third embodiment of this invention; and
[0015] FIG. 7 is a front view of a cylinder head used in the
compressor illustrated in FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Referring to FIGS. 1 through 3, description will be made of
a compressor according to a first embodiment of this invention.
[0017] The compressor illustrated in the figure comprises a
compressor housing 1, a plurality of cylinder bores 2 disposed in
the compressor housing 1 and spaced from one another in a
circumferential direction, a plurality of pistons 3 reciprocally
movable in the cylinder bores 2, respectively, a swash plate 4
slidably engaged with one ends of the pistons 3, and a drive shaft
5 for rotating the swash plate 4. The drive shaft 5 has one end
coupled with a pulley 6. By supplying an external drive force to
the pulley 6, the drive shaft 5 is rotated.
[0018] The swash plate 4 is connected through a hinge 7a to a rotor
7 rotating integrally with the drive shaft 5. Thus, the swash plate
4 is tiltably rotated. Herein, the swash plate 4 is urged towards
the pistons 3 by a coil spring 7b wound around the drive shaft
5.
[0019] The compressor further comprises a cylinder head 10 disposed
to be opposite to one end of the compressor housing 1 and a valve
plate 9 interposed between the compressor housing 1 and the
cylinder head 10. The cylinder head 10 has a refrigerant suction
chamber 10a and a refrigerant discharge chamber 10b. In other
words, the cylinder head 10 defines the refrigerant suction chamber
10a and the refrigerant discharge chamber 10b. The refrigerant
suction chamber 10a and the refrigerant discharge chamber 10b
communicate with each of the cylinder bores 2 through a refrigerant
suction port 9a and a refrigerant discharge port 9b of the valve
plate 9, respectively. In this case, the refrigerant discharge
chamber 10b is disposed at a radially center area of the cylinder
head 10 while the refrigerant suction chamber 10a in an annular
shape is formed around the refrigerant discharge chamber 10b.
[0020] The valve plate 9 is provided with a valve stopper 9c inside
the refrigerant discharge chamber 10b. The valve plate 9 cooperates
with a part of the valve plate 9 to control an aperture of the
refrigerant discharge port 9b to a predetermined or desired
aperture.
[0021] When the drive shaft 5 is rotated in response to the
external drive force supplied to the pulley 6, the swash plate 4 is
rotated together with the drive shaft 5. Owing to the inclination
of the swash plate 4, each piston 3 reciprocally moves in an axial
direction. As a consequence, the refrigerant is sucked from the
refrigerant suction chamber 10a in the cylinder head 10 into the
cylinder bores 2 and then discharged to the refrigerant discharge
chamber 10b in the cylinder head 10. Due to a pressure difference
between the refrigerant suction chamber 10a and a crank chamber 1a
of the compressor housing 1, each piston 3 is applied with a
pressure on its rear side (on the side of the crank chamber 1a).
Depending upon the above-mentioned pressure, the stroke of each
piston 3 and the tilting angle of the swash plate 4 are changed so
that the discharge volume of the refrigerant is varied.
[0022] The cylinder head 10 comprises a first part 101 defining the
refrigerant suction chamber 10a and a second part 102 defining the
refrigerant discharge chamber 10b. The cylinder head 11 is formed
with a space 10c located between the first part 101 and the second
part 102. The space 10c is formed by a groove which opens to the
outside of the cylinder head 11
[0023] More in detail, the space 10c is formed along a
circumferential direction of each of the refrigerant suction
chamber 10a and the refrigerant discharge chamber 10b and has a
depth nearly reaching a particular end face 100 of the cylinder
head 10. Furthermore, the space 10c is divided in a circumferential
direction of the cylinder head 10 into a plurality of, i.e., three
small spaces 10c-1, 10c-2, and 10c-3. Between every adjacent ones
of the small spaces 10c-1, 10c-2, and 10c-3, a reinforcing part 10d
is formed to extend towards both the refrigerant suction chamber
10a and the refrigerant discharge chamber 10b.
[0024] By reciprocal motion of each of the pistons 3, the
refrigerant in the refrigerant suction chamber 10a is sucked into
each of the cylinder bores 2 and then discharged from the cylinder
bore 2 to the refrigerant discharge chamber 10b. During this
process, a temperature difference is produced between the
refrigerant or suction-side refrigerant in the refrigerant suction
chamber 10a and the refrigerant or discharge-side refrigerant in
the refrigerant discharge chamber 10b. However, since the space 10c
is formed between the first and the second parts 101 and 102, no
direct heat transfer occurs therebetween. It is therefore possible
to reliably prevent temperature elevation of the refrigerant in the
refrigerant suction chamber 10a due to heat transfer from the
refrigerant discharge chamber 10b.
[0025] With the compressor described in conjunction with FIGS. 1
through 3, the space 10c formed between the first and the second
parts 101 and 102 serves to insulate the refrigerant suction
chamber 10a and the refrigerant discharge chamber 10b from each
other. Therefore, any additional element such as an insulator is
not required so that a decrease in productivity and an increase in
cost can be avoided.
[0026] Furthermore, the space 10c is formed by the groove which
opens to the outside of the cylinder head 10. Therefore, the space
10c can be kept in a low-temperature condition by ambient air. This
contributes to a further increase of a heat insulation effect
between the refrigerant suction chamber 10a and the refrigerant
discharge chamber 10b.
[0027] The space 10c is divided in the circumferential direction of
the cylinder head 10 into a plurality of, i.e., three small spaces
10c-1, 10c-2, and 10c-3. Between every adjacent small spaces 10c-1,
10c-2, and 10c-3, the reinforcing part 10d is formed. With this
structure, it is possible to reliably prevent a decrease in
mechanical strength of the cylinder head 10 due to presence of the
space 10c and to improve the durability.
[0028] Furthermore, even if the temperature difference between the
suction-side refrigerant and the discharge-side refrigerant is
great, temperature elevation of the suction-side refrigerant due to
heat transfer from the refrigerant discharge chamber 10b can
reliably be prevented as described above. This allows the use of a
carbon dioxide refrigerant high in working pressure. The use of the
carbon dioxide refrigerant makes it possible to realize a
refrigerant circuit advantageous in environment protection, leading
to an extremely large advantage in case where the compressor is
used in an automotive air conditioner.
[0029] Referring to FIGS. 4 and 5, the description will be made of
a compressor according to a second embodiment of this invention.
Similar parts are designated by like reference numerals and
description thereof may be omitted.
[0030] A cylinder head 11 has a refrigerant suction chamber 11a and
a refrigerant discharge chamber 11b. The refrigerant suction
chamber 11a and the refrigerant discharge chamber 11b communicate
with each of the cylinder bores 2 through a refrigerant suction
port 9d and a refrigerant discharge port 9e of the valve plate 9,
respectively. The refrigerant suction chamber 11a is disposed at a
radially center area of the cylinder head 11 while the refrigerant
discharge chamber 11b in an annular shape is formed around the
refrigerant suction chamber 11a. Inside the refrigerant suction
chamber 11a, the valve plate 9 is provided with a valve stopper 9f
for the refrigerant discharge port 9e.
[0031] The cylinder head 11 comprises a first part 111 defining the
refrigerant discharge chamber 11b and a second part 112 defining
the refrigerant suction chamber 11a. The cylinder head 11 is formed
with a space 11c located between the first part 111 and the second
part 112. The space 11c is formed by a groove which opens to the
outside of the cylinder head 11. More in detail, the space 11c is
formed along a circumferential direction of each of the refrigerant
suction chamber 11a and the refrigerant discharge chamber 11b and
has a depth nearly reaching a particular end face 110 of the
cylinder head 11.
[0032] The space 11c is divided in a circumferential direction of
the cylinder head 11 into a plurality of, i.e., three small spaces
11c-1, 11c-2, and 11c-3. Between every adjacent ones of the small
spaces 11c-1, 11c-2, and 11c-3, a reinforcing part 11d is formed to
extend towards both the first and the second parts 111 and 112 of
the cylindrical head 11.
[0033] The cylinder head 11 is provided with a plurality of
heat-release protrusions or ribs 11e formed on an outer surface of
the first part 111. More in detail, the ribs 11e are formed at a
plurality of positions on the outer surface of the first part 111
of the cylinder head 11 and are spaced from one another in the
circumferential direction of the cylinder head 11.
[0034] By reciprocal motion of each of the pistons 3, the
refrigerant in the refrigerant suction chamber 11a is sucked into
each of the cylinder bores 2 and then discharged from the cylinder
bore 2 to the refrigerant discharge chamber 11b. Since the
refrigerant suction chamber 11a and the refrigerant discharge
chamber 11b are insulated by the space 11c formed therebetween, a
temperature difference between the refrigerant in the refrigerant
suction chamber 10a and the refrigerant in the refrigerant
discharge chamber 10b causes no problem.
[0035] Since the refrigerant discharge chamber 11b is formed around
the refrigerant suction chamber 11a, i.e., on an outer peripheral
side of the cylinder head 11, a large contact area is assured
between the outer surface of the first part 111 and ambient air.
Thus, the heat of the refrigerant in the refrigerant discharge
chamber 11b can actively be released towards the outer surface of
the cylinder head 11. As a consequence, heat transfer from the
refrigerant discharge chamber 11b to the refrigerant suction
chamber 11a is suppressed so as to further improve the heat
insulation effect of the space 11c. In addition, the ribs 11e
formed on the outer surface of the first part 111 of the cylinder
head 11 contribute to promotion of the heat release from the outer
surface of the cylinder head 11. Therefore, it is possible to yet
further improve the heat insulation effect of the space 11c.
[0036] Referring to FIGS. 6 and 7, the description will be made of
a compressor according to a third embodiment of this invention.
Similar parts are designated by like reference numerals and
description thereof will be omitted.
[0037] A cylinder head 12 has a refrigerant suction chamber 12a and
a refrigerant discharge chamber 12b. The refrigerant suction
chamber 12a and the refrigerant discharge chamber 12b communicate
with each of the cylinder bores 2 through the refrigerant suction
port 9a and the refrigerant discharge port 9b of the valve plate,
respectively. The refrigerant discharge chamber 12b is disposed at
a radially center area of the cylinder head 12 while the
refrigerant suction chamber 12a in an annular shape is formed
around the refrigerant discharge chamber 12b. The cylinder head 12
is provided with a first space 12c located between the refrigerant
suction chamber 12a and the refrigerant discharge chamber 12b. The
first space 12c is formed by a groove which opens on the side of
one end face (on the side adjacent to the compressor housing 1) of
the cylinder head 12. More in detail, the first space 12c is formed
along a circumferential direction of each of the refrigerant
suction chamber 12a and the refrigerant discharge chamber 12b and
has a depth nearly reaching the other end face (on the side
opposite to the compressor housing 1) of the cylinder head 12.
[0038] The first space 12c is divided in a circumferential
direction of the cylinder head 12 into a plurality of parts.
Between every adjacent parts of the space 12c, a reinforcing part
12d is formed to extend towards both the refrigerant suction
chamber 12a and the refrigerant discharge chamber 12b. Each
reinforcing part 12d is provided with a second space 12e located
between the refrigerant suction chamber 12a and the refrigerant
discharge chamber 12b. The second space 12e is formed by a hole
which opens on the side of one end face (on the side adjacent to
the compressor housing 1) of the cylinder head 12. Thus, each of
the first and the second spaces 12c and 12e is tightly sealed with
respect to the outside of the cylinder head 12.
[0039] The cylinder head 12 has a first refrigerant path 12f
defined by a small hole for communication between the first space
12c and the refrigerant suction chamber 12a, and a second
refrigerant path 12g for communication between the second space 12e
and the refrigerant suction chamber 12a. The refrigerant in the
refrigerant suction chamber 12a flows through the refrigerant paths
12f and 12g into the spaces 12c and 12e, respectively. In this
case, the first refrigerant path 12f is defined by the small hole
formed at a general center of the cylinder head 12 in the thickness
direction. The second refrigerant path 12g is defined by a groove
formed at one end face of the cylinder head 12. The second
refrigerant path 12g may be understood as a gap left between the
cylinder head 12 and the valve plate 9.
[0040] By reciprocal motion of each of the pistons 3, the
refrigerant in the refrigerant suction chamber 12a is sucked into
each of the cylinder bores 2 and then discharged from the cylinder
bore 2 to the refrigerant discharge chamber 12b. During this
process, the refrigerant suction chamber 12a and the refrigerant
discharge chamber 12b are thermally insulated by the first and the
second spaces 12c and 12e formed between the refrigerant suction
chamber 12a and the refrigerant discharge chamber 12b.
[0041] Each of the first and the second spaces 12c and 12e is
tightly sealed with respect to the outside of the cylinder head 12
and the refrigerant in the refrigerant suction chamber 12a is
introduced into the first and the second spaces 12c and 12e through
the first and the second refrigerant paths 12f and 12g,
respectively. Therefore, each of the spaces 12c and 12e can be kept
in a low-temperature condition by the suction-side refrigerant low
in temperature so that the heat insulation effect of the first and
the second spaces 12c and 12e can further be improved.
[0042] While the present invention has thus far been described in
connection with a few embodiments thereof, it will readily be
possible for those skilled in the art to put this invention into
practice in various other manners. In the foregoing, description
has been made about the compressor which is varied in discharge
volume by changing the tilting angle of the swash plate 4 with
respect to the drive shaft 5. Alternatively, by forming an integral
member corresponding to a combination of the swash plate 4 and the
rotor 7, it is possible to provide a fixed-volume or
fixed-displacement compressor comprising a swash plate having a
predetermined fixed tilting angle with respect to the drive shaft
5. Further, this invention is not limited to such a swash-plate
compressor but may be applicable to other various types of
compressors, such as a vibration compressor, a scroll-type
compressor, and a vane-type compressor, as far as the compressor
has a structure in which the refrigerant suction chamber and the
refrigerant discharge chamber are closely adjacent to each other.
Furthermore, in a compressor using chlorofluorocarbon as a
refrigerant, the similar effect can be obtained.
* * * * *