Information
-
Patent Grant
-
6572343
-
Patent Number
6,572,343
-
Date Filed
Tuesday, September 18, 200122 years ago
-
Date Issued
Tuesday, June 3, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Walberg; Teresa
- Fastovsky; Leonid M
Agents
-
CPC
-
US Classifications
Field of Search
US
- 417 269
- 417 571
- 092 71
- 062 217
- 184 616
-
International Classifications
-
Abstract
The deformation of cylinder bores in a cylinder block is prevented. The cylinder block 19 is inserted into a front housing 11. The cylinder block 19 is fixed to the front housing 11 by tightening plural screws 38 which penetrate through the cylinder block 19, from an end surface 191 side thereof, to be screwed into an end wall 32 of the front housing 11. Plural deformation absorbing grooves 39 are provided on the end surface 191. Each one of the deformation absorbing grooves 39 is provided in each intermediate space between the adjacent paired cylinder bores 41.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cylinder block for a piston type compressor in which plural cylinder bores are provided in the cylinder block and arranged around a rotating shaft, a piston is housed in each cylinder bore, then each of the pistons is reciprocated in the cylinder bore based on the rotation of the rotating shaft, and each piston causes refrigerant gas to be drawn into a compression chamber, which is defined in the cylinder bore and then discharged from the compression chamber.
2. Description of the Related Art
In a piston type compressor of a variable displacement type, as disclosed in Japanese Unexamined Patent Publication,(Kokai) No. 11-193780, a cylinder block that contains cylinder bores that guide pistons is assembled as a part of a housing assembly of the compressor and the housing assembly comprises a pair of housings (a front housing and a rear housing) and a cylinder block. The cylinder block is clamped by the pair of housings so as to constitute a part of an outer wall of the housing assembly. Plural bolts penetrate the front housing and the cylinder block and are screwed into the rear housing. The pair of housings and the cylinder block are assembled and fixed so as to constitute the housing assembly by tightening the bolts.
The cylinder bores housing the pistons in the cylinder block are arranged at approximately equal intervals around the axis of the rotating shaft and the bolts penetrate between the adjacent cylinder bores and are near the outer circumference of the cylinder block. The bolts penetrate through a crank chamber in the front housing and the end surface of a cylindrical circumferential wall of the front housing is coupled with the outer circumferential portion of an end surface of the cylinder block. In this structure, in which the front housing and the cylinder block are coupled to each other, the tightening force of the bolts causes the cylinder block to be deformed slightly and the cylindrical cylinder bores are then deformed. The deformation of the cylindrical cylinder bores prevents the pistons from moving smoothly. Besides, unnecessarily large clearances, between the circumferential surfaces of the pistons and the circumferential surfaces of the cylinder bores, are created, so that the refrigerant compressed in the cylinder bores leaks into the crank chamber through the clearances between the circumferential surfaces of the pistons and the circumferential surfaces of the cylinder bores. The excessive leakage of the refrigerant from the cylinder bores to the crank chamber disturbs the pressure in the crank chamber, which should be regulated, so that the displacement control in the compressor of a variable displacement type becomes unstable.
A piston type compressor in which a cylinder block is included in a housing assembly constituted by coupling a first housing to a second housing is disclosed, for example, in Japanese Unexamined Patent Publication (Kokai) No. 10-306773. The structure in which the cylinder block is included in the housing assembly prevents the coupling portions between the first housing and the cylinder block, and the coupling portions between the second housing and the cylinder block, from being exposed on the outside of the compressor. The hiding of the coupling portions is effective for reducing the possibility of leakage of refrigerant from the compressor.
The cylinder block is held, for example, by being interposed between the first housing and the second housing. In the piston type compressor in which the cylinder block is located inside the housings, the diameter of the cylinder block tends to be small. Therefore, in the structure in which the first housing comes into contact with the one end surface of the cylinder block and the second housing comes into contact with the other end surface of the cylinder block and then both of the housings are coupled by tightening bolts, a cylinder block with small diameter is easily deformed.
SUMMARY OF THE INVENTION
The object of the present invention is to prevent the cylinder bores in the cylinder block from being deformed.
Therefore, the present invention applies to a piston type compressor in which plural cylinder bores are provided in a cylinder block and arranged around a rotating shaft, a piston is housed in each cylinder bore, then each of the pistons is reciprocated in the cylinder bore based on the rotation of the rotating shaft, and the piston causes refrigerant gas to be drawn into a compression chamber which is defined in the cylinder bore and then discharged from the compression chamber. In the first aspect of the present invention, a deformation absorbing gap that absorbs the deformation of the cylinder block is provided, for at least a pair of the adjacent paired cylinder bores, between the adjacent paired cylinder bores.
The deformation of the cylinder bores due to the deformation of the cylinder block is avoided by the enlargement and the contraction of the deformation absorbing gaps.
The present invention may be more fully understood from the description of the preferred embodiments of the invention set forth below, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1
is a profile cross-sectional view of the whole compressor in the first embodiment.
FIG. 2
is a section view taken along line A—A in FIG.
1
.
FIG. 3
is a section view taken along line B—B in FIG.
1
.
FIG. 4
is a section view taken along line C—C in FIG.
1
.
FIG. 5
is a perspective view of the cylinder block
19
.
FIG. 6
is a profile cross-sectional view of the whole compressor in the second embodiment.
FIG. 7
is a perspective view of the cylinder block
19
A.
FIG. 8
is a perspective view of the third embodiment.
FIG. 9A
is a profile cross-sectional view of the major components of the fourth embodiment.
FIG. 9B
is a perspective view of the cylinder block
19
C of the fourth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment, in which the present invention is embodied in a compressor of variable displacement type, is described with reference to FIG.
1
through FIG.
5
. Carbon dioxide is used as refrigerant in the present invention.
As shown in
FIG. 1
, the end surface of a circumferential wall
34
of a front housing
11
and the end surface of a circumferential wall
35
of a rear housing
12
are coupled to each other via a gasket
36
. The front housing
11
that is a first housing and the rear housing
12
that is a second housing are fixed each other, by tightening plural bolts
37
, to constitute a housing assembly
10
.
A valve plate
20
, valve forming plates
21
and
22
, and a retainer forming plate
23
are inserted into the front housing
11
, and a suction chamber
111
and a discharge chamber
112
are defined between the valve plate
20
and an end wall
32
of the front housing
11
. The suction chamber
111
and the discharge chamber
112
are separated by the partition wall
33
and the suction chamber
111
is surrounded by the discharge chamber
112
. A top surface
331
of the partition wall
33
comes into contact with the retainer forming plate
23
and the outer circumferential edge of the retainer forming plate
23
is jointed to a step
341
formed in the inner circumference of the circumferential wall
34
of the front housing
11
.
A cylinder block
19
is inserted in the front housing
11
so as to be jointed to the valve forming plate
21
. The cylinder block
19
is fixed to the front housing
11
by tightening the plural screws
38
penetrating through the cylinder block
19
from the end surface
191
side of the cylinder block
19
so that the plural screws
38
are screwed into the end wall
32
of the front housing
11
. Screw through-holes
195
and bolt through-holes
196
penetrate through the cylinder block
19
from the end surface
191
so as to reach an end surface
194
. The plural cylinder bores
41
(only one is shown in
FIG. 1
, though there are five in this embodiment as shown in FIG.
3
through FIG.
5
), are provided in the cylinder block
19
. A screw through-hole
195
and a bolt through-hole
196
are provided in each space between the adjacent cylinder bores
41
. The screws
38
penetrate through the screw through-holes
195
and also penetrate the suction chamber
111
surrounded by the partition wall
33
. The bolts
37
penetrate through the bolt through-holes
196
.
A rotating shaft
13
is supported, by the cylinder block
19
and the rear housing
12
that forms a control pressure chamber
121
, so that the rotating shaft
13
can rotate. The rotation shaft
13
which passes through a shaft aperture
192
of the cylinder block
19
and a shaft aperture
113
of the front housing
11
to protrude outside the compressor receives a rotational drive force from an external power source (a vehicle engine, for example). A shaft sealing member
45
, installed in the shaft aperture
113
, prevents refrigerant from leaking from the suction chamber
111
to the outer side of the compressor along the circumferential surface of the rotating shaft
13
. A shaft sealing member
40
installed in the shaft aperture
192
prevents refrigerant from leaking from the control pressure chamber
121
to the suction chamber
111
along the circumferential surface of the rotating shaft
13
.
Not only is a rotary support
14
fixed to the rotating shaft
13
but, also, a swash plate
15
is supported by the rotating shaft
13
so that the swash plate
15
can slide, move, and incline in the axial direction of the rotating shaft
13
. As shown in
FIG. 2
, a pair of guide pins
16
is fixed to the swash plate
15
. The guide pins
16
fixed to the swash plate
15
are slidably inserted into guide holes
141
formed on the rotary support
14
. By engagement with the guide holes
141
and the guide pins
16
, the swash plate
15
can move and incline in the axial direction of the rotating shaft
13
and rotate integrally with the rotating shaft
13
. Inclination and movement of the swash plate
15
is guided by the relationship between the guide holes
141
and the guide pins
16
, and the slide supporting action of the rotating shaft
13
.
As shown in
FIG. 1
, a piston
17
is housed in each cylinder bore
41
. The pistons
17
define compression chambers
411
in the cylinder bores
41
. The rotational motion of the swash plate
15
, which rotates integrally with the rotating shaft
13
, is converted into a reciprocating motion of the piston
17
via shoes
18
, and the pistons
17
move back and forth in the cylinder bores
41
.
The refrigerant in the suction chamber
111
, which is a suction pressure area, flows into the compression chamber
411
, after pushing back a suction valve
211
on a valve forming plate
21
, from a suction port
201
on a valve plate
20
, due to the reversing motion (movement from left to right in
FIG. 1
) of the piston
17
. The refrigerant that flows into the compression chamber
411
is discharged to the discharge chamber
112
, which is a discharge pressure area, from a discharge port
202
on the valve plate
20
, after pushing back a discharge valve
221
on a valve forming plate
22
, due to the advancing motion (movement from right to left in
FIG. 1
) of the piston
17
. The discharge valve
221
comes into contact with a retainer
231
on a retainer forming plate
23
, resulting in a restriction on the opening of the discharge valve
221
.
As shown in FIG.
4
and
FIG. 5
, plural deformation absorbing grooves
39
are formed on an end surface
191
which is located on the control pressure chamber
121
side and opposite to the compression chambers
411
in the cylinder block
19
. The deformation absorbing grooves
39
are provided in intermediate spaces between adjacent cylinder bores
41
so as to cross the screw through-holes
195
and bolt through-holes
196
. The deformation absorbing grooves
39
reach an outer circumferential surface
193
of the cylinder block
19
from the shaft aperture
192
in the radial direction. Moreover, the depth of the deformation absorbing grooves
39
is designed to be within a range in which the deformation absorbing grooves
39
do not reach the position of the shaft sealing member
40
.
As shown in
FIG. 1
, a pressure supply passage
30
, which connects the discharge chamber
112
and the control pressure chamber
121
, passes the refrigerant in the discharge chamber
111
to the control pressure chamber
121
. The refrigerant in the control pressure chamber
121
flows out into the suction chamber
111
through a pressure release passage
31
that connects the control pressure chamber
121
and the suction chamber
111
. An electromagnetic displacement control valve
25
is interposed on the pressure supply passage
30
. The displacement control valve
25
is controlled by a controller (not shown), which controls the energization and de-energization of the displacement control valve
25
based on the passenger compartment temperature detected by a passenger compartment temperature detector (not shown), which detects the passenger compartment temperature in a vehicle, and the target passenger compartment temperature set by a passenger compartment temperature adjuster (not shown).
The displacement control valve
25
is open when it is not energized with current, and it is closed when it is energized with current. That is, the refrigerant in the discharge chamber
112
is supplied to the control pressure chamber
121
when the displacement control valve
25
is de-energized and the refrigerant in the discharge chamber
112
is not supplied to the control pressure chamber
121
when the displacement control valve
25
is energized. The displacement control valve
25
controls the supply of the refrigerant from the discharge chamber
112
to the control pressure chamber
121
.
The inclination angle of the swash plate
15
is changed based on the pressure control in the control pressure chamber
121
. When the pressure in the control pressure chamber
121
increases, the inclination angle of the swash plate
15
decreases, and when the pressure in the control pressure chamber
121
decreases, the inclination angle of the swash plate
15
increases. When refrigerant is supplied from the discharge chamber
112
to the control pressure chamber
121
, the pressure in the control pressure chamber
121
increases, and when the supply of refrigerant from the discharge chamber
112
to the control pressure chamber
121
is terminated, the pressure in the control pressure chamber
121
decreases. That is, the inclination angle of the swash plate
15
is controlled by the displacement control valve
25
.
The maximum inclination angle of the swash plate
15
is defined when the swash plate
15
comes into contact with the rotary support
14
. The minimum inclination angle of the swash plate
15
is defined when a circlip
24
on the rotating shaft
13
comes into contact with the swash plate
15
.
The discharge chamber
112
and the suction chamber
111
are connected via an external refrigerant circuit
26
. The refrigerant, which flows out from the discharge chamber
112
into the external refrigerant circuit
26
, is fed back to the suction chamber
111
via a condenser
27
, an expansion valve
28
, and an evaporator
29
.
The following effects can be obtained in the first embodiment.
(1-1)
The cylinder block
19
which is fixed to the front housing
11
by tightening the plural screws
38
is deformed by the tightening force of the screws
38
. The tightening force of the screws
38
is received by a partition wall
33
and the step
341
of the front housing
11
and the screws
38
pass through the suction chamber
111
, that is, the inside of the annular partition wall
33
. Thus, the tightening force of the screws
38
causes the cylinder block
19
to be deformed so that the end surface
191
of the cylinder block
19
is concaved. Such deformation causes the diameter of the cylinder block
19
at the end surface
191
side to be reduced so as to cause the circular shape of the cylinder bores
41
to be deformed.
If all the spaces between the adjacent cylinder bores
41
are filled with solid portions which form the cylinder block
19
, the cylinder block
19
deforms intensively around the periphery of the cylinder bores
41
, so that the circular shape of the cylinder bores
41
is deformed greatly.
However, if the deformation absorbing grooves
39
are provided in the solid portions between the adjacent cylinder bores
41
, when the cylinder block
19
is deformed by the tightening force of the screws
38
, the ends of the solid portions, facing each other, approach each other in situation in which the deformation absorbing grooves
39
are made to be boundaries. Moreover, as described above, as the tightening force of the screws
38
causes the cylinder block
19
to be deformed so that the end surface
191
of the cylinder block
19
is concaved, the adjacent cylinder bores
41
are moved toward the center of the cylinder block
19
in radial direction and approach each other in circumferential direction. Therefore, the deformation of the circular shape of the cylinder bores
41
is prevented. In other words, the deformation of the cylinder bores
41
due to the deformation of the cylinder block
19
is prevented by reducing the width of the deformation absorbing grooves
39
.
(1-2)
The deformation absorbing groove
39
, which is designed as an embodiment of the deformation absorbing gap, is provided in each of all solid portions between the adjacent cylinder bores
41
. Therefore, due to the tightening force of the screws
38
, all the paired facing ends of solid portions around the cylinder bores
41
approach each other at equal distance and because the end surface
191
of the cylinder block
19
is concaved, the adjacent cylinder bores
41
are equally moved toward the center of the cylinder block
19
in radial direction and equally approach each other in circumferential direction, so that the deformations of all the cylinder bores
41
are equally reduced.
(1-3)
The deformation absorbing grooves
39
can be produced with the cylinder block
19
while molding the cylinder block
19
, or can be produced by cutting after molding the cylinder block
19
. In both cases, the production of the deformation absorbing grooves
39
is easy and the deformation absorbing grooves
39
which are provided on the end surface
191
of the cylinder block
19
are simple and convenient as an embodiment of the deformation absorbing gaps.
(1-4)
The deformation absorbing grooves
39
are provided on the end surface
191
side of the cylinder block
19
, exposed to the control pressure chamber
121
. The bottoms of the deformation absorbing grooves
39
are prevented from reaching the location positions of the compression chamber
411
and the shaft sealing member
40
, so that the control pressure chamber
121
cannot communicate with the compression chamber
411
and the suction chamber
111
through the deformation absorbing grooves
39
. Such structure in which the deformation absorbing grooves
39
are provided on the end surface
191
, which is located on the control pressure chamber
121
side and opposite to the compression chamber
411
, is simple and convenient for preventing the deformation absorbing grooves
39
from reaching the location position of the compression chamber
411
and the shaft sealing member
40
. Therefore, the end surface
191
opposite to the compression chamber
411
is optimal as the forming position of the deformation absorbing grooves
39
.
(1-5)
The deformation absorbing grooves
39
having a length from the shaft aperture
192
of the cylinder block
19
to the outer circumferential surface
193
are preferable for preventing the deformation of the cylinder bores
41
due to the deformation of the cylinder block
19
.
(1-6)
The cylinder block
19
included in the housing assembly
10
is generally smaller than that exposed on the outside of a compressor. The smaller the cylinder block is, the easier the cylinder bores are deformed. The present invention is specially effective for applying to a piston type compressor including a small cylinder block
19
.
(1-7)
The operating pressure of carbon dioxide refrigerant is higher than that of the chlorofluorocarbon type refrigerant. The increase of the operation pressure of the refrigerant makes the refrigeration more efficient, so that the size of a compressor can be reduced by reducing the volume of the cylinder bores
41
. That is, the size of the cylinder block
19
in a compressor, which uses carbon dioxide refrigerant, can be reduced in comparison with that of the cylinder block in a compressor, which uses chlorofluorocarbon type refrigerant. Therefore, the present invention is specially effective for the application to the piston type compressor using carbon dioxide refrigerant.
Next, the second embodiment in FIG.
6
and
FIG. 7
is described. The same symbols are attached to the same components as in the first embodiment.
In this embodiment, a suction chamber
122
and a discharge chamber
123
are provided at a rear housing
12
A side, and the valve plate
20
, the valve forming plates
21
and
22
, the retainer forming plate
23
and a cylinder block
19
A are inserted into the rear housing
12
A. The cylinder block
19
A is pressed and inserted into the rear housing
12
A. A step
351
provided in the inner circumference side of a circumferential wall
35
A of the rear housing
12
A determines the position of the cylinder block
19
A with respect to the rear housing
12
A.
A control pressure chamber
114
is provided in a circumferential wall
34
A of a front housing
11
A and the rotating shaft
13
is supported by the cylinder block
19
A and the front housing
11
A so as to be able to rotate. A pressure supply passage which connects the discharge chamber
123
and the control pressure chamber
114
is indicated by
30
A and a pressure release passage which connects the control pressure chamber
114
and the suction chamber
122
is indicated by
31
A.
Deformation absorbing grooves
42
and
43
are formed on the end surfaces
197
and
198
of the cylinder block
19
A. The cylinder block
19
A pressed and inserted into the rear housing
12
A is deformed by the reaction force of press insertion so that the diameter thereof is reduced, while the deformation absorbing grooves
42
and
43
prevent the cylinder bores
41
from being deformed as much as in the case of the first embodiment of the present invention. The deformation absorbing grooves
42
prevent the circular shape of the cylinder bores
41
at the end surface
197
side from being deformed and the deformation absorbing grooves
43
prevent the circular shape of the cylinder bores
41
at the end surface
198
side from being deformed.
Next, the third embodiment in
FIG. 8
is described. The same symbols are attached to the same components as in the first embodiment.
A cylinder block
19
B is inserted into the front housing
11
(not shown). Deformation absorbing grooves
44
are provided in the outer circumferential surface
193
of the cylinder block
19
B so as to partition the adjacent cylinder bores
41
. The deformation absorbing grooves
44
extend from the one end surface
191
of the cylinder block
19
B to the other end surface
194
(not shown) thereof. The deformation absorbing grooves
44
prevent the circular shape of the cylinder bores
41
from being deformed along the whole length of the cylinder bores
41
.
Next, the fourth embodiment in FIG.
9
A and
FIG. 9B
is described. The same symbols are attached to the same components as in the second embodiment.
A cylinder block
19
C comprises a base plate portion
45
for supporting the rotating shaft
13
and plural bore forming protrusions
46
installed on the base plate portion
45
. The cylinder bores
41
are formed in the base plate portion
45
and the bore forming protrusions
46
so as to penetrate therethrough and a shaft aperture
192
is formed in the base plate portion
45
.
As shown in
FIG. 9B
, plural bore forming protrusions
46
are spaced apart each other and the gaps between the respective bore forming protrusions
46
prevent the circular shape of the cylinder bores
41
from being deformed.
In the present invention, the following embodiments may be realized.
(1) The number of the deformation absorbing gaps is reduced so that the number of the deformation absorbing gaps is less than that of pairs of the adjacent paired cylinder bores.
(2) Plural pieces of cylinder block pieces are assembled to construct a cylinder block and to provide gaps between adjacent connecting portions of the respective cylinder block pieces so that the gaps act as the deformation absorbing gaps.
(3) The present invention is applied to a piston type compressor in which a cylinder block forms a part of an outer wall of a housing assembly, as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 11-193780.
In this case, it is necessary to prevent the deformation absorbing gaps from being exposed on the outside of the housing assembly.
(4) The present invention is applied to a piston type compressor of a fixed displacement type.
(5) The present invention is applied to a piston type compressor in which chlorofluorocarbon type refrigerant is used.
As described above, the present invention, in which the deformation absorbing gap for absorbing the deformation of the cylinder block is provided between at least a pair of the adjacent paired cylinder bores, can be expected to bring an excellent effect in that the deformation of the cylinder bores can be prevented in the cylinder block.
While the invention has been described by reference to specific embodiments chosen for the purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention.
Claims
- 1. A cylinder block in a piston type compressor:wherein plural cylinder bores are provided in the cylinder block and arranged around a rotating shaft, a piston is housed in each cylinder bore, the respective pistons are reciprocated in the cylinder bores based on the rotation of the rotating shaft, and the pistons cause refrigerant gas to be drawn into compression chambers which are defined in the cylinder bores and then discharged from the compression chambers; and wherein a deformation absorbing gap for absorbing the deformation of the cylinder block is provided between at least a pair of the adjacent paired cylinder bores.
- 2. A cylinder block in a piston type compressor, as set forth in claim 1, wherein the deformation absorbing gaps are provided in all the spaces between the adjacent paired cylinder bores.
- 3. A cylinder block in a piston type compressor, as set forth in claim 1, wherein the deformation absorbing gaps are deformation absorbing grooves formed on an end surface of the cylinder block so that the deformation absorbing grooves are provided along the radial direction of the cylinder block.
- 4. A cylinder block in a piston type compressor, as set forth in claim 3, wherein the end surface of the cylinder block is opposite to the compression chambers side.
- 5. A cylinder block in a piston type compressor, as set forth in claim 3, wherein the deformation absorbing grooves reach an outer circumferential surface of the cylinder block from a shaft aperture which is penetrated by the rotating shaft in the cylinder block.
- 6. A cylinder block in a piston type compressor, as set forth in claim 1, wherein the cylinder block is included in an inner side of a housing assembly constituted by coupling a first housing to a second housing.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-306182 |
Oct 2000 |
JP |
|
US Referenced Citations (8)
Foreign Referenced Citations (2)
Number |
Date |
Country |
404058077 |
Feb 1992 |
JP |
407054770 |
Feb 1995 |
JP |