Information
-
Patent Grant
-
6382938
-
Patent Number
6,382,938
-
Date Filed
Friday, September 8, 200024 years ago
-
Date Issued
Tuesday, May 7, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Walberg; Teresa
- Patel; Vinod D.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 417 540
- 417 269
- 417 340
- 417 2222
- 417 542
- 417 437
-
International Classifications
-
Abstract
A compressor that reduces pressure pulsation includes a mounting member for attaching the compressor to a vehicle support. The mounting member is integrally formed with an end wall of a rear housing member. A suction chamber and a discharge chamber are defined in the rear housing member. The discharge chamber is located outside the suction chamber and surrounds the suction chamber. An auxiliary chamber is formed in the mounting member. The auxiliary chamber is centrally located. The auxiliary chamber increases the volume of the suction chamber, which reduces pulsation. Since the auxiliary chamber is formed in the mounting member, neither the weight or the volume of parts that might interfere with other devices is increased.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a compressor having a structure for suppressing pulsation.
A typical compressor includes a rotatable shaft, piston s housed in cylinder bores, a suction chamber and discharge chamber. As each piston is reciprocated in the corresponding cylinder bore by rotation of the rotatable shaft, gas is drawn into the cylinder bore from the suction chamber, which is defined in a rear housing member. The gas is then compressed by the piston and discharged to the discharge chamber, which is defined in the rear housing member.
The discharge chamber suppresses pulsation of discharged gas, and the suction chamber suppresses pulsation of drawn gas. The greater the volume of the discharge chamber is , the more effectively the discharge pulsation suppression is. Also, the greater the volume of the suction chamber is, the more effective the suction pulsation suppression is.
Japanese Unexamined Patent Publication No. 11-125178discloses a compressor that suppresses discharge pulsation. The compressor of the publication has a bracket protruding from a rear housing member. The outer wall of the rear housing member bulges by the same amount as the bracket. The bulge is hollow, and the interior of tho bulge forms part of a discharge chamber. This structure e increases the volume of the discharge chamber, which improves the pulsation suppression without increasing the axial dimension of the compressor.
However, such expansion of the discharge chamber expands the total area of the walls defining the discharge chamber, which increases the weight of the compressor. Although the axial dimension of the compressor is not increased, the volume of the compressor increased. As a result, the compressor is more likely to interfere with other devices. The increased weight and size are disadvantageous when installing the compressor in a vehicle.
SUMMARY OF THE INVENTION
Accordingly, it is an objective of the present invention to provide a compressor that effectively suppresses pressure pulsation without increasing the weight of the compressor or the volume of any part that might cause interference during installation.
In accordance with the present invention, there is provided a compressor comprising a housing having a suction chamber and a discharge chamber defined therein. Gas is drawn from the suction chamber into cylinder bores and discharged from the cylinder bores into the discharge chamber by the reciprocating movement of a plurality of pistons driven by the rotation of a rotatable shaft. The housing is provided with a mounting member for attaching the compressor to a mounting object outside the compressor. The mounting member is fixed to the wall of the housing adjacent to at least one of the suction chamber and the discharge chamber. An auxiliary chamber that augments at least one of the suction chamber and the discharge chamber is formed by a recess in the wall at the location of the mounting member.
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
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:
FIG. 1
is a cross-sectional view illustrating a compressor according to a first embodiment of the present invention;
FIG. 2
is a rear view of the compressor shown in
FIG. 1
;
FIG. 3
is a cross-sectional view taken along line
3
—
3
of
FIG. 1
;
FIG. 4
is a cross-sectional view taken along line
4
—
4
of
FIG. 1
;
FIG. 5
is a rear view illustrating a compressor according to a second embodiment;
FIG. 6
is a cross-sectional view taken along line
6
—
6
of
FIG. 5
;
FIG. 7
is a cross-sectional view illustrating a compressor according to a third embodiment of the present invention;
FIG. 8
is a rear view similar to
FIG. 2
illustrating a compressor according to a fourth embodiment of the present invention; and
FIG. 9
is a cross-sectional view similar to
FIG. 3
illustrating the compressor of FIG.
8
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, like numerals are used for like elements throughout.
A variable displacement compressor according to a first embodiment of the present invention will now be described with reference to
FIGS. 1
to
4
. The compressor is used in a vehicle.
As shown in
FIG. 1
, the housing of the compressor includes a front housing member
12
, a cylinder block
11
and a rear housing member
17
. A control pressure chamber
121
is defined by the front housing member
12
and the cylinder block
11
. A rotatable shaft
13
is supported by the front housing member
12
and the cylinder block
11
and is rotated by a vehicle engine (not shown). A swash plate
14
is supported by the rotatable shaft
13
in the control pressure chamber
121
. The swash plate
14
rotates integrally with and inclines relative to the rotatable shaft
13
. Cylinder bores
111
, the number of which is six in this embodiment, are formed in the cylinder block
11
about the rotatable shaft
13
. A piston
15
is housed in each cylinder bore
111
. Rotation of the swash plate
14
is converted into reciprocation of each piston
15
by shoes
16
.
A rear housing member
17
is coupled to the cylinder block
11
. A rear housing member
17
is secured to the cylinder block
11
with a valve plate
18
, two valve flap plates
19
,
20
and a retainer plate
21
. A suction chamber
22
, which is a suction pressure zone, and a discharge chamber
23
, which is a discharge pressure zone, are defined in the rear housing member
17
. As shown in
FIGS. 3 and 4
, the suction chamber
22
and the discharge chamber
23
are divided by a substantially annular wall
25
. The wall
25
extends from an end wall
24
of the rear housing member
17
in the axial direction of the compressor. The discharge chamber
23
is located radially outside of the suction chamber
22
.
Suction ports
181
are formed in the valve plate
18
. As shown in
FIG. 4
, the suction ports
181
are located radially inside of the wall
25
. Each suction port
181
corresponds to one of the cylinder bores
111
. The suction ports
181
are arranged on a circle C centered on a point
131
, which is on the axis of the rotatable shaft
13
. Discharge ports
182
are formed in the valve plate
18
. The discharge ports
182
are located radially outside of the wall
25
. Each discharge port
182
corresponds to one of the cylinder bores
111
. Suction valve flaps
191
are formed on the suction valve flap plate
19
. Discharge valve flaps
201
are formed on the discharge valve flap plate
20
. Each suction valve flap
191
opens and closes the corresponding suction port
181
. Each discharge valve flap
201
opens and closes the corresponding discharge port
182
.
A gas introduction passage
30
is formed adjacent to the end wall
24
of the rear housing member
17
. The passage
30
extends from a circumferential wall
31
of the rear housing member
17
through the discharge chamber
23
and opens to the suction chamber
22
. An outlet
301
of the passage
30
is located in the vicinity of the center point
131
of the circle C.
When each piston
15
is moved from the top dead center position to the bottom dead center position, refrigerant gas is drawn into the corresponding cylinder bore
111
from the suction chamber
22
through the corresponding suction port
181
and past the corresponding suction valve flap
191
. When each piston
15
is moved from the bottom dead center position to the top dead center position, the refrigerant gas is compressed in the cylinder bore
111
and is then discharged to the discharge chamber
23
through the corresponding discharge port
182
and past the corresponding discharge valve flap
201
. Retainers
211
are formed on the retainer plate
21
to limit the opening degree of the discharge valve flaps
201
. Refrigerant in the discharge chamber
23
then flows to the suction chamber
22
through the external refrigerant circuit
32
, which includes the condenser
33
, the expansion valve
34
, the evaporator
35
and the gas introduction passage
30
.
The discharge chamber
23
is connected to the control pressure chamber
121
by a supply passage
26
. The supply passage
26
supplies refrigerant from the discharge chamber
23
to the control pressure chamber
121
. An electromagnetic displacement control valve
27
is located in the supply passage
26
. The control valve
27
is controlled by a controller (not shown). The controller determines the value of current supplied to the control valve
27
based on the vehicle compartment temperature, which is detected by a compartment temperature sensor (not shown), and a target temperature, which is set by a temperature adjuster (not shown). The control valve
27
then operates based on the suction pressure in the suction chamber
22
and sets the actual suction pressure to a value that corresponds to the value of the supplied current. When the value of the supplied current is increased, the control valve
27
decreases the flow rate of refrigerant from the discharge chamber
23
to the control pressure chamber
121
. Since refrigerant flows to the suction chamber
22
from the control pressure chamber
121
through a pressure release passage
29
, the pressure in the control pressure chamber
121
decreases. Accordingly, the inclination angle of the swash plate
14
is increased, which increases the displacement of the compressor. The increase in the compressor displacement lowers the suction pressure. When the value of the supplied current is decreased, the control valve
27
increases the flow rate of refrigerant from the discharge chamber
23
to the control pressure chamber
121
, which raises the pressure in the control pressure chamber
121
. Accordingly, the inclination angle of the swash plate
14
decreases and the displacement is decreased. The decrease in the displacement raises the suction pressure. When the value of the current is zero, the opening degree of the control valve
27
is maximized, and the inclination angle of the swash plate
14
is minimized as illustrated by a broken line in FIG.
1
.
As shown in
FIG. 1
, mounting members
36
,
37
are integrally formed with the front housing member
12
at the upper and lower surfaces. Bolt holes
361
,
371
are formed in the mounting members
36
,
37
, respectively. The holes
361
,
371
extend parallel to each other and perpendicular to the rotatable shaft
13
. As shown in
FIGS. 1 and 2
, a mounting member
28
is formed integrally with the rear housing member
17
at the rear surface of the end wall
24
. The mounting member
28
corresponds to the suction chamber
22
with the wall
24
in between. A bolt hole
281
is formed in the mounting member
28
. The hole
281
extends parallel to the holes
361
,
371
and perpendicular to the shaft
13
.
As shown in
FIG. 2
, bolts
38
,
39
,
40
are inserted into the holes
361
,
371
,
281
to fix the compressor to supporting parts
41
,
42
,
43
within a vehicle's engine compartment.
As shown in
FIGS. 1 and 3
, the suction chamber
22
is surrounded by the wall
25
and the end wall
24
of the rear housing member
17
. An auxiliary chamber
44
is formed in the mounting member
28
. Specifically, the auxiliary chamber
44
is formed by an axially extending recess in the end wall
24
at the location of the mounting member
28
. The auxiliary chamber
44
communicates with the suction chamber
22
, which increases the volume of the suction chamber
22
. An axial projection of the auxiliary chamber
44
includes the radial center of the suction chamber
22
.
The first embodiment has the following advantages.
(1-1) The mounting members
28
,
36
,
37
are necessary for installing the compressor in the vehicle. The auxiliary chamber
44
is formed in the mounting member
28
. Therefore, the volume of the suction chamber
22
is increased without increasing the weight and the volume of the compressor. The increase of the volume of the suction chamber
22
reduces the suction pulsation. Accordingly, noise and vibration created in the evaporator
35
due to the pulsation are reduced.
(1-2) The gas introduction passage
30
extends from the periphery of the compressor to the suction chamber
22
. Therefore, the gas passage
30
is longer than the radial dimension of the discharge chamber
23
. The passage
30
functions as a restrictor that reduces the suction pulsation.
(1-3) The outlet
301
of the passage
30
is near the center point
131
of the circle on which the suction ports
181
are located. The radial center of the suction chamber
22
lies within an axial projection of the auxiliary chamber
44
. The suction chamber
22
, which includes the auxiliary chamber
44
, is generally cylindrical. The location of the outlet
301
is therefore spaced substantially equally from each suction port
181
, which minimizes the pressure fluctuation at the outlet
301
. Pressure fluctuations at the outlet
301
create suction pulsation, which is transmitted to the external refrigerant circuit
32
through the passage
30
. The evaporator
35
, which is located in the passenger compartment, is vibrated by an element of the pulsation that has a resonance frequency. However, since the pressure fluctuation is minimized, the suction pulsation is minimized. The noise caused by the vibration of the evaporator
35
is reduced, accordingly.
A second embodiment will now be described with reference to
FIGS. 5 and 6
. Like or the same reference numerals are given to those components that are like or the same as the corresponding components of the embodiment of
FIGS. 1
to
4
.
In this embodiment, a bulge
45
is formed in the mounting member
28
. The bulge
45
however does not hinder the installation of the compressor due to its location. A second auxiliary chamber
451
is formed in the bulge
45
. The second auxiliary chamber
451
is a recess formed in the surface
241
of the end wall
24
that faces the suction chamber
22
. The auxiliary chambers
44
,
451
form part of the suction chamber
22
.
A third embodiment will now be described with reference to FIG.
7
. Like or the same reference numerals are given to those components that are like or the same as the corresponding components of the embodiment of
FIGS. 1
to
4
.
In this embodiment, a discharge chamber
23
A is located radially inside in the rear housing member
17
and a suction chamber
22
A is located radially outside of the discharge chamber
23
A. A displacement control valve
27
A controls the flow rate of refrigerant supplied from the discharge chamber
23
A to the control pressure chamber
121
through a refrigerant supply passage
26
A. Also, refrigerant flows from the control pressure chamber
121
to the suction chamber
22
A through a pressure release passage
112
, which has a throttle. The pressure in the control pressure chamber
121
is determined by the flow rate of refrigerant through the pressure release passage
112
and the flow rate of refrigerant from the control valve
27
A to the control pressure chamber
121
through the refrigerant supply passage
26
A.
An auxiliary chamber
44
A is formed in a mounting member
28
A and extends from the surface
242
of the end wall
24
of the discharge chamber
23
A. The auxiliary chamber
44
A forms part of the discharge chamber
23
A. The volume of the discharge chamber
23
A is increased by the volume of the auxiliary chamber
44
A. The radial center of the discharge chamber
23
A lies within an axial projection of the auxiliary chamber
44
A.
The auxiliary chamber
44
A, which is formed in the mounting member
28
A, increases the volume of the discharge chamber
23
A without increasing the weight and volume of the compressor. The augmentation of the discharge chamber
23
A reduces the discharge pulsation.
It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the invention may be embodied in the following forms.
(1) In the illustrated embodiments, the auxiliary chambers
44
,
44
A extend from the surfaces
241
,
242
of the end wall
24
into the interior of the mounting members
28
,
28
A, respectively. However, as long as the chambers
44
,
44
A are formed by axially extending recesses in the end wall
24
at the location of the mounting members
28
,
28
A, the chambers
44
,
44
A need not extend into the interior of the mounting members
28
,
28
A. In this case, if the auxiliary chambers are formed by recesses in the end wall at locations not corresponding to the mounting members, the strength of the wall at those locations is lowered. However, in the present invention, such a problem does not occur, because the recesses are formed in the end wall at the locations of the mounting members.
(2) In each illustrated embodiment, the chamber
22
or
23
A that is located inside is connected to the auxiliary chamber
44
,
44
A. However, if the rear housing member
17
has a mounting member that extends near both the suction chamber
22
,
22
A and the discharge chamber
23
,
23
A, two auxiliary chambers
45
A,
45
B may be formed to augment the suction chamber
22
,
22
A and the discharge chamber
23
,
23
A, respectively, as shown in
FIGS. 8 and 9
.
(3) The mounting members
28
,
28
A are integrally formed with the end wall
24
of the rear housing member
17
. However, the mounting member
28
,
28
A may be formed on the circumferential wall
31
. In this case, an auxiliary chamber may be formed in the mounting member to increase the volume of a peripheral chamber. That is, in the first and second embodiments, such an auxiliary chamber would increase the volume of the discharge chamber
23
. In the third embodiment, such an auxiliary chamber would increase the volume of the suction chamber
22
A.
Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.
Claims
- 1. A compressor comprising:a rotatable shaft; a housing having a wall, wherein a suction chamber and a discharge chamber are defined by the wall; a piston that is reciprocated by the rotation of the rotatable shaft, wherein the piston causes gas to be drawn from the suction chamber and to be discharged into the discharge chamber; a mounting member for attaching the compressor to a support, wherein the mounting member is fixed to the wall, and the mounting member is adjacent to at least one of the suction chamber and the discharge chamber; and an auxiliary chamber that augments at least one of the suction chamber and the discharge chamber, the auxiliary chamber being formed by a recess in the wall at the location of the mounting member.
- 2. A compressor according to claim 1, wherein the auxiliary chamber extends into the interior of the mounting member.
- 3. A compressor according to claim 1, wherein the suction chamber is located radially inward of the discharge chamber, wherein the mounting member is located adjacent to the suction chamber.
- 4. A compressor according to claim 3, wherein the auxiliary chamber is located near the axis of the rotatable shaft.
- 5. A compressor according to claim 3, further comprising a gas introducing passage provided in the housing, wherein the gas introducing passage extends between the periphery of the compressor and the suction chamber.
- 6. A compressor according to claim 1, wherein the discharge chamber is located radially inward of the suction chamber, wherein the mounting member is located adjacent to the discharge chamber.
- 7. A compressor according to claim 6, wherein the auxiliary chamber is located near the axis of the rotatable shaft.
- 8. A compressor according to claim 1, wherein the housing includes an outer peripheral wall, an end wall and a partition separating the suction chamber from the discharge chamber, and the mounting member is located on the end wall.
- 9. A compressor according to claim 1, wherein the mounting member is adjacent to both the suction chamber and the discharge chamber.
- 10. A compressor according to claim 9, wherein the auxiliary chamber includes a first chamber and a second chamber that augment the suction chamber and the discharge chamber, respectively, the first chamber and the second chamber being formed respectively by recesses in the wall.
- 11. A compressor according to claim 10, wherein each of the first chamber and the second chamber extends into the interior of the mounting member.
- 12. A compressor comprising:a rotatable shaft; a housing that includes a suction chamber and a discharge chamber, wherein the housing includes an outer peripheral wall, an end wall, and a partition, which separates the suction chamber and the discharge chamber from one another, wherein the suction chamber is radially inward of the discharge chamber; a piston that is reciprocated by the rotation of the rotatable shaft, wherein the piston causes gas to be drawn from the suction chamber and to be discharged into the discharge chamber; a mounting member for attaching the compressor to a support, the mounting member being located on the end wall adjacent to the suction chamber; and an auxiliary chamber formed by a hollow that extends from the suction chamber to the interior of the mounting member to increase the volume of the suction chamber.
- 13. A compressor according to claim 12, wherein the auxiliary chamber is located near the axis of the rotatable shaft.
- 14. A compressor according to claim 12, further comprising a gas introducing passage provided in the housing, wherein the gas introducing passage extends between the periphery of the compressor and the suction chamber.
- 15. A compressor comprising:a rotatable shaft; a housing that includes a suction chamber and a discharge chamber, wherein the housing includes an outer peripheral wall, an end wall, and a partition, which separates the suction chamber and the discharge chamber from one another, wherein the discharge chamber is radially inward of the suction chamber; a piston that is reciprocated by the rotation of the rotatable shaft, the piston causing gas to be drawn from the suction chamber and to be discharged into the discharge chamber; a mounting member for attaching the compressor to a support, the mounting member being located on the end wall adjacent to the discharge chamber; and an auxiliary chamber formed by a hollow that extends from the discharge chamber to the interior of the mounting member to increase the volume of the discharge chamber.
- 16. A compressor according to claim 15, wherein the auxiliary chamber is located near the axis of the rotatable shaft.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-260292 |
Sep 1999 |
JP |
|
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A |
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A |
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A |
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Number |
Date |
Country |
11-125178 |
May 1999 |
JP |