U.S. patent application number 15/462122 was filed with the patent office on 2017-09-28 for variable displacement type swash plate compressor.
This patent application is currently assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. The applicant listed for this patent is KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. Invention is credited to Kei NISHII, Takahiro SUZUKI, Shinya YAMAMOTO, Hideharu YAMASHITA.
Application Number | 20170276126 15/462122 |
Document ID | / |
Family ID | 59898412 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170276126 |
Kind Code |
A1 |
SUZUKI; Takahiro ; et
al. |
September 28, 2017 |
VARIABLE DISPLACEMENT TYPE SWASH PLATE COMPRESSOR
Abstract
A variable displacement type swash plate compressor includes a
housing having therein a swash plate chamber and a plurality of
cylinder bores, a drive shaft, a swash plate, a link mechanism, and
a plurality of the pistons. The compressor further includes a
partition member, a movable member, and a control pressure chamber,
and a control mechanism. First and second seal members are disposed
between the partition member and the movable member and between the
drive shaft and the movable member, respectively, and are
elastically deformed to provide sealing between the control
pressure chamber and the swash plate chamber. At least one of a
clearance formed between the partition member and the movable
member and a clearance formed between the drive shaft and the
movable member when the swash plate is at its minimum inclination
angle is greater than when the swash plate at a maximum inclination
angle position.
Inventors: |
SUZUKI; Takahiro;
(Kariya-shi, JP) ; YAMASHITA; Hideharu;
(Kariya-shi, JP) ; NISHII; Kei; (Kariya-shi,
JP) ; YAMAMOTO; Shinya; (Kariya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOYOTA JIDOSHOKKI |
Kariya-shi |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Kariya-shi
JP
|
Family ID: |
59898412 |
Appl. No.: |
15/462122 |
Filed: |
March 17, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 27/0891 20130101;
F04B 27/18 20130101; F04B 27/1804 20130101; F04B 27/1036 20130101;
F04B 27/12 20130101; F04B 27/0878 20130101; F04B 27/1054 20130101;
F04B 27/1072 20130101 |
International
Class: |
F04B 27/18 20060101
F04B027/18; F04B 27/12 20060101 F04B027/12; F04B 27/10 20060101
F04B027/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2016 |
JP |
2016-057935 |
Claims
1. A variable displacement type swash plate compressor comprising:
a housing having therein a swash plate chamber and a plurality of
cylinder bores; a drive shaft rotatably supported in the housing; a
swash plate mounted on the drive shaft for rotation therewith in
the swash plate chamber; a link mechanism permitting changing of an
inclination angle of the swash plate with respect to the an
imaginary plane extending perpendicular to a direction of an axis
of the drive shaft; a plurality of pistons received in the
respective cylinder bores and connected to the swash plate, the
pistons being reciprocally movable with the rotation of the drive
shaft with a stroke length that is determined by the inclination
angle of the swash plate; a partition member mounted on the drive
shaft for rotation therewith in the swash plate chamber; a movable
member mounted on the drive shaft for rotation therewith in the
swash plate chamber, the movable member being movable in the
direction of the axis along the drive shaft and the partition
member to change the inclination angle; a control pressure chamber
formed between the partition member and the movable member, the
control pressure chamber moving the movable member in a direction
that increases the inclination angle with an increase of a pressure
in the control pressure chamber; and a control mechanism
controlling the pressure in the control pressure chamber; wherein a
first seal member is disoposed between the partition member and the
movable member, and the first seal member is elastically deformed
to provide sealing between the control pressure chamber and the
swash plate chamber, wherein a second seal member is disposed the
drive shaft and the movable member, and the second seal member is
elastically deformed to provide sealing between the control
pressure chamber and the swash plate chamber, and wherein a
clearance formed between the partition member and the movable
member when the swash plate is at a minimum inclination angle is
greater than the clearance formed between the partition member and
the movable member when the swash plate is at a maximum inclination
angle and/or a clearance formed between the drive shaft and the
movable member when the swash plate is at the minimum inclination
angle is greater than the clearance formed between the drive shaft
and the movable member when the swash plate is at the maximum
inclination angle.
2. The variable displacement type swash plate compressor according
to claim 1, wherein only the clearance formed between the partition
member and the movable member when the swash plate is at the
minimum inclination angle is greater than the clearance formed
between the partition member and the movable member when the swash
plate is at the maximum inclination angle.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a variable displacement
type swash plate compressor.
[0002] Japanese Patent Application Publication H05-172052 discloses
a variable displacement type swash plate compressor (hereinafter
simply referred to as compressor) which is shown in FIGS. 1 and 3.
The compressor includes a housing, a drive shaft, a swash plate, a
link mechanism, a plurality of pistons, a movable member and a
control pressure chamber and a control mechanism. The housing has
therein a plurality of cylinder bores, a swash plate chamber and a
pressure control chamber. The housing further has therein a center
hole that is connected to the swash plate chamber and the pressure
control chamber.
[0003] The drive shaft is rotatably supported in the housing. The
swash plate is rotatable with the rotation of the drive shaft in
the swash plate chamber. The link mechanism is disposed between the
drive shaft and the swash plate and permits changing of an
inclination angle of the swash plate relative to an imaginary plane
extending perpendicularly to the axis of the drive shaft. Each
piston is reciprocally movably received in the cylinder bore so as
to form a compression chamber therewith. A pair of shoes, which
serves as part of a conversion mechanism, is disposed between each
piston and the swash plate. With the rotation of the swash plate,
the piston is caused to move reciprocally in the cylinder bore with
a piston stroke length that is determined in accordance with the
inclination of the swash plate.
[0004] The movable member is mounted on the drive shaft in the
center hole of the housing. The movable member is axially slidably
movable in the center hole so as to change the inclination angle of
the swash plate. The movable member partitions between the pressure
control chamber and the swash plate chamber. The movable member
includes a seal member. The seal member is elastically deformed
between the outer peripheral surface of the movable member and the
inner peripheral surface of the center hole so as to seal
therebetween. The control mechanism controls the pressure in the
control pressure chamber.
[0005] In this compressor, when the pressure in the control
pressure chamber is increased by the control mechanism, the movable
member is slidably moved in the axial direction of the drive shaft
towards the front housing in the axial hole, so that the
inclination angle of the swash plate is increased through the link
mechanism. Accordingly, the discharge volume per rotation of the
drive shaft and hence the displacement of the compressor is
increased. When the pressure in the control pressure chamber is
reduced by the control mechanism, on the other hand, the movable
member is slidably moved in the axial direction of the drive shaft
toward the rear housing in the axial hole, so that the inclination
angle of the swash plate is reduced through the link mechanism.
Accordingly, the discharge volume per rotation of the drive shaft
and hence the displacement of the compressor is reduced.
[0006] In the above-described compressor, the sliding movement of
the movable member causes the seal member to be elastically
deformed between the outer peripheral surface of the movable member
and the inner peripheral surface of the axial hole while being
moved axially. In increasing the displacement of the compressor by
increasing the inclination angle of the swash plate, the pressure
in the control pressure chamber acting on the movable member to
slide axially need be increased enough to overcome the slide
resistance of the seal member acting against the movement of the
movable member. When the pressure in the control pressure chamber
is decreased, the resistance of the seal member acting on the
movable member becomes large for the pressure in the control
pressure chamber acting on the movable member. Such resistance
makes difficult the sliding movement of the movable member thereby
to cause difficulty in increasing the inclination angle of the
swash plate and hence the displacement of the compressor.
Therefore, controlling the displacement of the compressor may
become complicated.
[0007] The present invention, which has been made in light of the
above-described problems, is directed to providing a variable
displacement type swash plate compressor that permits precise
controlling of the displacement of the compressor
SUMMARY OF THE INVENTION
[0008] In accordance with an aspect of the present invention, there
is provided a variable displacement type swash plate compressor
including a housing having therein a swash plate chamber and a
plurality of cylinder bores, a drive shaft rotatably supported in
the housing, a swash plate mounted on the drive shaft for rotation
therewith in the swash plate chamber, a link mechanism permitting
changing of an inclination angle of the swash plate with respect to
the an imaginary plane extending perpendicular to a direction of an
axis of the drive shaft, and a plurality of the pistons received in
the respective cylinder bores and connected to the swash plate, the
pistons being reciprocally movable with the rotation of the drive
shaft with a stroke length that is determined by the inclination
angle of the swash plate. The compressor further includes a
partition member mounted on the drive shaft for rotation therewith
in the swash plate chamber, a movable member mounted on the drive
shaft for rotation therewith in the swash plate chamber, and a
control pressure chamber formed between the partition member and
the movable member. The movable member is movable in the direction
of the axis along with the drive shaft and the partition member to
change the inclination angle. The control pressure chamber moves
the movable member in the direction that increases the inclination
angle with an increase of a pressure in the control chamber. The
compressor further includes a control mechanism controlling the
pressure in the control chamber. A first seal member is disposed
between the partition member and the movable member and elastically
deformed to provide sealing between the control pressure chamber
and the swash plate chamber. A second seal member is disposed
between the drive shaft and the movable member and is elastically
deformed to provide sealing between the control pressure chamber
and the swash plate chamber. A clearance formed between the
partition member and the movable member when the swash plate is at
a minimum inclination angle is greater than the clearance formed
between the partition member and the movable member when the swash
plate is at a maximum inclination angle position and/or a clearance
formed between the drive shaft and the movable member when the
swash plate is at the minimum inclination angle is greater than the
clearance formed between the drive shaft and the movable member
when the swash plate is at the maximum inclination angle.
[0009] 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
[0010] FIG. 1 is a longitudinal sectional view of a compressor
according to a first embodiment of the present invention, showing a
state of the compressor with the swash plate at its minimum
inclination angle position;
[0011] FIG. 2 is a longitudinal sectional view of the compressor of
FIG.1, showing a state of the compressor with the swash plate at
its maximum inclination angle position;
[0012] FIG. 3 is a schematic diagram of a control mechanism of the
compressor of FIG.1;
[0013] FIG. 4 is an enlarged fragmentary cross-sectional view of
the compressor of FIG. 1, showing a drive shaft, a partition
member, a movable member and a control pressure chamber;
[0014] FIG. 5 is an enlarged fragmentary cross-sectional view of
the compressor of FIG. 1, showing a clearance between the partition
member and the movable member when the inclination angle is
large;
[0015] FIG. 6 is an enlarged fragmentary cross-sectional view of
the compressor of FIG. 1, showing a clearance between the partition
member and the movable member when the inclination angle is
small;
[0016] FIG. 7 is an enlarged fragmentary cross-sectional view of a
compressor according to a comparison example, showing a drive
shaft, a partition member, a movable member and a control pressure
chamber;
[0017] FIG. 8 is a chart showing a change of pressure in the
control pressure chamber acting on the movable member and changes
of resistance of O-rings acting on the movable member in the
compressor of FIG. 7;
[0018] FIG. 9 is a chart showing a change of pressure in the
control pressure chamber acting on the movable member and changes
of resistance of O-rings acting on the movable member in the
compressor of FIG. 1;
[0019] FIG. 10 is an enlarged fragmentary cross-sectional view of a
compressor according to a second embodiment of the present
invention, showing a drive shaft, a partition member, a movable
member and a control pressure chamber;
[0020] FIG. 11 is an enlarged fragmentary cross-sectional view of a
compressor according to a third embodiment of the present
invention, showing a drive shaft, a partition member, a movable
member and a control pressure chamber;
[0021] FIG. 12 is an enlarged fragmentary cross-sectional view of a
compressor according to a fourth embodiment of the present
invention, showing a drive shaft, a partition member, a movable
member and a control pressure chamber;
[0022] FIG. 13 is an enlarged fragmentary cross-sectional view of
the compressor of FIG. 12, showing a clearance between the
partition member and the movable member when the inclination angle
is large;
[0023] FIG. 14 is an enlarged fragmentary cross-sectional view of
the compressor of FIG. 12, showing a clearance between the
partition member and the movable member when the inclination angle
is small;
[0024] FIG. 15 is an enlarged fragmentary cross-sectional view of a
compressor according to a fifth embodiment of the present
invention, showing a drive shaft, a partition member, a movable
member and a control pressure chamber; and
[0025] FIG. 16 is an enlarged fragmentary cross-sectional view of a
compressor according to a sixth embodiment of the present
invention, showing a drive shaft, a partition member, a movable
member and a control pressure chamber.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] The following will describe a variable displacement type
swash plate compressor (hereinafter simply referred to as
compressor) according to various embodiments of the present
invention with reference to the accompanying drawings. The
compressor of the embodiments is mounted on a vehicle and forms a
part of a refrigeration circuit of a vehicle air conditioner.
[0027] Referring to FIGS. 1 and 2, there is shown a compressor
according to a first embodiment of the present invention. The
compressor includes a housing 1, a drive shaft 3, a swash plate 5,
a link mechanism 7, a plurality of pistons 9, a plurality of pairs
of shoes 11a, 11b and an actuator 13. As shown in FIG. 3, the
compressor further includes a control mechanism 15.
[0028] As shown in FIGS. 1 and 2, the housing 1 includes a front
housing member 17, a rear housing member 19, a first cylinder block
21, a second cylinder clock 23, a first valve forming plate 39 and
a second valve forming plate 41. In the compressor according to the
present embodiment, the sides of the compressor where the front
housing member 17 and the rear housing member 19 are positioned
correspond to the front and the rear of the compressor,
respectively. In addition, the top and the bottom of the
illustration of FIGS. 1 and 2 will be referred to the top and the
bottom of the compressor. It is to be noted that the front and the
rear of the compressor may be changed in accordance with the
mounting of the compressor in the vehicle.
[0029] The front housing member 17 is formed with a boss 17a
projecting frontward and having therein a shaft seal device 25. A
first suction chamber 27a and a first discharge chamber 29a are
formed in the front housing member 17. The first suction chamber
27a has an annular shape and is positioned on the radially inner
side of the front housing member 17. The first discharge chamber
29a has also an annular shape and is disposed radially outward of
the first suction housing 27a.
[0030] A part of the aforementioned control mechanism 15 is formed
in the rear housing member 19. The rear housing member 19 has
therein a second suction chamber 27b and a second discharge chamber
29b and a pressure control chamber 31. The pressure control chamber
31 is positioned in the center of the rear housing member 19. The
second suction chamber 27b has an annular shape and is positioned
radially outward of the pressure control chamber 31. The second
discharge chamber 29b has also an annular shape and is disposed
radially outward of the second suction chamber 27b. The first
discharge chamber 29a and the second discharge chamber 29b are
connected to each other through a discharge passage (not shown).
The discharge passage is connected to a discharge port (not
shown).
[0031] The first cylinder block 21 is disposed between the front
housing member 17 and the second cylinder block 23. The first
cylinder block 21 has therein a plurality of first cylinder bores
21a extending in the direction of the axis O of the drive shaft 3.
The first cylinder bores 21a are spaced angularly at a regular
interval in the circumferential direction of the cylinder block
21.
[0032] The first cylinder block 21 has therein a first shaft hole
21b through which the drive shaft 3 is inserted. A first slide
bearing 22a is provided in the first shaft hole 21b to support the
drive shaft. Additionally, the first cylinder block 21 further has
therein a first recess 21c that is connected to the rear end of the
first shaft hole 21b. The first recess 21c and the first shaft hole
21b are formed coaxially. The first recess 21c has a diameter
greater than that of the first shaft hole 21b. A first thrust
bearing 35a is mounted in the first recess 21c. The first cylinder
block 21 has therein a first communication passage 37a extending in
the axial direction.
[0033] The second cylinder block 23 is disposed between the first
cylinder block 21 and the rear housing member 19. With the second
cylinder block 23 and the first cylinder block 21 connected
together, a swash plate chamber 33 is formed therebetween. The
swash plate chamber 33 is connected to the first recess 21c so that
the first recess 21c forms a part of the swash plate chamber 33.
The swash plate chamber 33 is connected to the first communication
passage 37a.
[0034] The second cylinder block 23 has therein a plurality of
second cylinder bores 23a extending in the direction of the axis O
of the drive shaft 3 and having substantially the same diameter as
the first cylinder bores 21a. The second cylinder bores 23a are
spaced angularly at a regular interval. Each second cylinder bore
23a is paired and disposed coaxially with its corresponding first
cylinder bore 21a. According to the present invention, any number
of the first and second cylinder bores 21a, 23a may be formed in
the housing as long as the first and second cylinder bores 21a. 23a
are provided in pairs. The first cylinder bores 21a may have a
diameter different from that of the second cylinder bores 23a. The
paired first and second cylinder bores 21a, 23a need not
necessarily be coaxially disposed.
[0035] The second cylinder block 23 has therein a second shaft hole
23b through which the drive shaft 3 is inserted. A second slide
bearing 22b is provided in the second shaft hole 23b to support the
drive shaft 3. It is to be noted that the first and second slide
bearings 22a, 22b may be replaced with ball bearings.
[0036] A second recess 23c is formed in the second cylinder block
23 and connected to the front end of the second shaft hole 23b. The
second recess 23c is disposed coaxially with the second shaft hole
23b. The second recess 23c is formed with a diameter greater than
that of the second shaft hole 23b. The second recess 23c is
connected to the swash plate chamber 33 so as to form a part of the
swash plate chamber 33. A second thrust bearing 35b is mounted in
the second recess 23c.
[0037] The second cylinder block 23 has a suction port 330 and a
second communication passage 37b. The swash plate chamber 33 is
connected through the suction port 330 to an evaporator (not shown)
that is connected in the refrigeration circuit of the air
compressor. The second communication passage 37b extends in the
front-rear direction and communicates with the swash plate chamber
33.
[0038] The first housing 17 and the first cylinder block 21 are
joined together with the first valve forming plate 39 interposed
therebetween.
[0039] The first valve forming plate 39 has therethough a first
suction hole 390a and a first discharge hole 390b for each first
cylinder bore 21a and a first suction communication hole 390c. Each
first cylinder bore 21a is communicable with the first suction
chamber 27a via the first suction hole 390a and also with the first
discharge chamber 29a via the first discharge hole 390b. The first
suction chamber 27a and the first communication passage 37a are in
communication with each other through the first suction
communication hole 390c.
[0040] The rear housing member 19 and the second cylinder block 23
are joined together with the second valve forming plate 39
interposed therebetween.
[0041] The second valve forming plate 41 has therethough a second
suction hole 410a and a second discharge hole 410b for each second
cylinder bore 23a and a second suction communication hole 410c.
Each second cylinder bore 23a is communicable with the second
suction chamber 27b via the second suction hole 410a and also with
the second discharge chamber 29b via the second discharge hole
410b. The second suction chamber 29a and the second communication
passage 37b are in communication with each other through the second
suction communication hole 410c.
[0042] Although not illustrated in the drawing, the first valve
forming plate 39 has a plurality of first suction reed valves that
open and close the respective first suction holes 390a, a plurality
of discharge reed valve that opens and closes the respective second
discharge holes 390b, and a retainer plate that restricts the
opening of each discharge reed valve. In addition, the second valve
forming plate 41 has a plurality of second suction reed valves that
open and close the respective second suction holes 410a, a
plurality of discharge reed valves that open and close the
respective second discharge holes 410b, and a retainer plate that
restricts the opening of each discharge reed valve. The first and
second cylinder blocks 21, 23 are formed with a retainer recess
that restricts the opening of each suction reed valve.
[0043] The first and second suction chambers 27a, 27b communicates
with the swash plate chamber 33 through the first and second
communication passages 37a, 37b and the first and second suction
communication passages 390c, 410c, respectively, so that pressures
in the first and second suction chambers 27a, 27b are substantially
the same as that in the swash plate chamber 33. Since low-pressured
refrigerant gas having passed through the evaporator is flowed into
the swash plate chamber 33 through the suction port 330, the
pressures in the swash plate chamber 33 as well as the first and
second suction chambers 27a, 27b are lower than those in the first
and second discharge chambers 29a, 29b.
[0044] The drive shaft 3 includes a drive shaft body 30, a first
support member 43a and a second support member 43b. The drive shaft
3 has at the front end thereof a threaded portion 3a. The drive
shaft 3 is connected to a pulley or an electromagnetic clutch
(neither shown) through the threaded portion 3a. Additionally, the
drive shaft 3 has therein an axial passage 3b and a radial passage
3c, which will be described later.
[0045] The drive shaft body 30 extends axially in the housing 1.
The drive shaft body 30 has at the front end thereof a first small
diameter portion 30a and at the rear end thereof a second small
diameter portion 30b.
[0046] The drive shaft body 30 has mounted thereon the swash plate
5, the link mechanism 7 and the actuator 13 that are disposed in
the swash plate chamber 33. The swash plate 5 is mounted on the
drive shaft 3 for rotation therewith in the swash plate chamber
33.
[0047] The first support member 43a has a generally cylindrical
shape extending along the axis O of the drive shaft 3. The first
support member 43a is press fitted on the first small diameter
portion 30a of the drive shaft body 30. The first support member
43a has a first flange 430 and a mounting portion (not shown)
through which a second pin 47b, which will be described later, is
inserted.
[0048] A return spring 44a is mounted around the first support
member 43a. The return spring 44a extends in the direction the axis
O between the first flange 430 and the swash plate 5.
[0049] The second support member 43B has a generally cylindrical
shape extending along the axis O of the drive shaft 3. The second
support member 43b is press fitted on the rear end of the second
small diameter portion 30a of the drive shaft body 30. The second
support member 43b has at the front thereof a second flange 431.
The second support member 43b further has a first seal ring 46a and
a second seal ring 46b disposed rearward of the second flange
431.
[0050] The drive shaft 3 extends through the shaft seal device 25,
the first suction chamber 27a, the first and second shaft holes
21b, 23b, the first and second thrust bearings 35a, 35b, the swash
plate chamber 33 and the pressure control chamber 31 in the housing
1, so that the drive shaft 3 is supported rotatably about the axis
O extending in the front-rear direction of the compressor in the
housing 1. With the drive shaft 3 thus supported by the housing 1,
the first thrust bearing 35a is held axially between the first
flange 430 of the first support member 43a and the front surface of
the first recess 21c. The first and second seal rings 46a, 46b are
disposed in the second shaft hole 23b so as to seal between the
pressure control chamber 31 and the swash plate chamber 33.
[0051] The swash plate 5 has a generally disk shape having a front
surface 5a and a rear surface 5b. The swash plate 5 is disposed in
the swash plate chamber 33 with the front surface 5a and the rear
surface 5b thereof facing frontward and rearward of the compressor,
respectively. In other words, the front surface 5a faces the front
housing member 17 and the rear surface 5b faces the rear housing
member 19.
[0052] The swash plate 5 includes a ring plate 45 that has a shape
of a circular disk having at the center thereof a hole 45a. The
swash plate 5 is mounted on the drive shaft 3 with the drive shaft
body 30 inserted through the hole 45a of the ring plate 45 of the
swash plate 5 in the swash plate chamber 33. The ring plate 45
further has therethrough a hole 45. The ring plate 45 further has a
connecting portion 45c projecting rearward from the rear surface 5b
of the swash plate 5. The connecting portion 45c is disposed
opposite from the hole 45b with respect to the axis O.
[0053] The link mechanism 7 includes a lug arm 49. The lug arm 49
is disposed frontward of the swash plate 5 in the swash plate
chamber 33 and positioned between the swash plate 5 and the first
support member 43a. The lug arm 49 has a generally L-shape and has
at the rear end thereof a weight 49a. The weight 49a may be
designed in any suitable shape.
[0054] The lug arm 49 is connected at the rear end thereof to the
ring plate 45 via a first pin 47a. Thus, the lug arm 49 is
supported swingably about a first axis M1 corresponding to the axis
of the first pin 47a and relative to the ring plate 45, or to the
swash plate 5.
[0055] The front end of the lug arm 49 is connected to the first
support member 43a by a second pin 47b in such a way that the lug
arm 49 is supported swingably about a second axis M2 corresponding
to the axis of the second pin 47b and relative to the first support
member 43a, or to the drive shaft 3. The lug arm 49, the first and
second pins 47a, 47b, a pair of connecting arms 132 and a third pin
47c, which will be described later, cooperate to form the link
mechanism 7 according to the present invention.
[0056] The weight 49a is provided on the rear side of the lug arm
49, that is, on the side of the lug arm 49 that is opposite from
the second axis M2 with respect to the first axis M1. With the lug
arm 49 supported by the ring plate 45 at the first pin 47a, the
weight 49a is located on the rear side of the ring plate 45, that
is, on the rear side of the rear surface 5b of the swash plate 5.
The centrifugal force caused by the rotation of the swash plate 5
about the axis O of the drive shaft 3 acts on the weight 49a on the
rear surface 5b of the swash plate 5.
[0057] The swash plate 5 is connected to the drive shaft 3 via the
link mechanism 7, so that the swash plate 5 is rotatable with the
drive shaft 3. With the swinging movement of the opposite ends of
the lug arm 49 about the first axis M1 and the second axis M2, the
inclination angle of the swash plate 5 with respect to an imaginary
plane extending perpendicularly to the axis O is variable between
the maximum inclination angle position shown in FIGS. 1 and the
minimum inclination angle position shown in FIGS. 2. In other
words, the link mechanism 7 permits changing of the inclination
angle of the swash plate 5 with respect to the imaginary plane
extending perpendicular to the direction of the axis O of the drive
shaft 3.
[0058] The piston 9 is a double-headed piston having at the front
end thereof a first head portion 9a and at the rear end thereof a
second head portion 9b, respectively, as shown in FIGS. 1 and 2.
The first head portion 9a is reciprocally movably received in the
first cylinder bore 21a and a first compression chamber 53a is
defined by the first head portion 9a and the first valve forming
plate 39 in the first cylinder bore 21a. The second head portion 9b
is reciprocally movably received in the second cylinder bore 23a
and a second compression chamber 53b is defined by the second head
portion 9b and the second valve forming plate 41 in the second
cylinder bore 23a.
[0059] Each piston 9 has therein at the center thereof a piston
recess 9c to receive therein a pair of hemispherical shoes 11a,
11b. The rotation of the swash plate 5 is converted to the
reciprocal movement of the piston 9 by way of the shoes 11a, 11b.
The shoes 11a, 11b correspond to the conversion mechanism of the
present invention. Thus, the first head portion 9a and the second
head portion 9b of the piston 9 are reciprocally movable in the
first cylinder bore 21a and the second cylinder bore 23a,
respectively, with a stroke length that is determined by the
inclination angle of the swash plate 5.
[0060] The top dead center positions of the first head portion 9a
and the second head portion 9b are variable with the change of the
stroke length that is caused by the change of the inclination angle
of the swash plate 5. Specifically, the top dead center of the
second head portion 9b moves a longer distance than the first head
portion 9a as the inclination angle of the swash plate 5 is
reduced, as shown in FIG. 1.
[0061] The actuator 13 is disposed rearward of the swash plate 5 in
the swash plate chamber 33. Specifically, the actuator 13 is
disposed in the region of the swash plate chamber 33 corresponding
to the second cylinder block 23 so that the actuator 13 is movable
into the second recess 23c.
[0062] As shown in FIG. 4, the actuator 13 has a movable member
13a, a partition member 13b and a control pressure chamber 13c. The
control pressure chamber 13c is formed between the movable member
13a and the partition member 13b.
[0063] The movable member 13a includes a bottom wall 130, a
peripheral wall 131, the aforementioned paired arms 132 (only one
arm being shown in FIG. 1) and an elastically deformable O-ring
51a. The O-ring 51a corresponds to the second seal member of the
present invention.
[0064] As shown in FIG. 4, the bottom wall 130 forms the rear part
of the movable member 13a, extending outwardly in the radial
direction of the axis O. The bottom wall 130 has therethrough a
hole 130a. The bottom wall 130 further has a first groove 130b
recessed from the circular inner surface forming the hole 130a of
the bottom wall 130. The O-ring 51a is disposed in the first groove
130b, so that the O-ring 51a is disposed between the drive shaft 3
and the movable member 13a. The peripheral wall 131 extends
frontward from the outer periphery of the bottom wall 130. The
movable member 13a has a bottomed cylindrical shape formed by the
bottom wall 130 and the peripheral wall 131. Each arm 132 has an
insertion hole 132a into which a third pin 47c, which will be
described later, is inserted.
[0065] The partition member 13b has a disk shape having an outer
diameter that is greater than the drive shaft body 30 and
substantially the same as the first inner diameter L1 of the
movable member 13a. The partition member 13b is provided with an
elastically deformable O-ring 51b. The O-ring 51b corresponds to
the first seal member according to the present invention. The
O-rings 51a, 51b for first and second seal members may be
substituted by X-rings.
[0066] The partition member 13b has at the center thereof a hole
133. The partition member 13b has an outer peripheral surface 134
in which a second groove 134a is formed. The O-ring 51b is disposed
in the second groove 134a, so that the O-ring 51b is disposed
between the partition member 13b and the movable member 13a. As has
been described, the partition member 13b has a diameter that is
greater than the drive shaft body 30, so that the diameter of the
O-ring 51b is greater than that of the O-ring 51a.
[0067] The second small diameter portion 30b of the drive shaft
body 30 is inserted through the insertion hole 130a of the movable
member 13a so that the movable member 13a is slidable along the
second small diameter portion 30b in the direction of the axis O.
The movable member 13a is mounted on the drive shaft 3 for rotation
therewith in the swash plate chamber 33. The second small diameter
portion 30b is press fitted in the hole 133 of the partition member
13b. Thus, the partition member 13b is fixedly mounted on the
second small diameter portion 30b of the drive shaft body 30 for
rotation therewith. The partition member 13b may be mounted
slidably on the second small diameter portion 30b along the
direction of the axis O.
[0068] The partition member 13b fixed on the second small diameter
portion 30b is disposed in the movable member 13a and
circumferentially surrounded by the peripheral wall 131 of the
movable member 13a. As the movable member 13a moves along the axis
O, the inner peripheral surface 131a of the peripheral wall 131
slides along the outer peripheral surface 134 of the partition
member 13b.
[0069] With the partition member 13b surrounded by the peripheral
wall 131, the control pressure chamber 13c is formed between the
movable member 13a and the partition member 13b. The control
pressure chamber 13c is defined in the swash plate chamber 33 by
the bottom wall 130 and the peripheral wall 131 of the movable
member 13a, the partition member 13b, and the outer peripheral
surface 300 of the drive shaft 3.
[0070] With the second small diameter portion 30b inserted through
the movable member 13a, the O-ring 51a is positioned and
elastically deformed between the outer peripheral surface 300 of
the second small diameter portion 30b and the movable member 13a,
thus providing sealing between the control pressure chamber 13c and
the swash plate chamber 33. With the partition member 13b
surrounded by the peripheral wall 131 of the movable member 13a,
the O-ring 51b is positioned between the partition member 13b and
the movable member 13a. The O-ring 51b is elastically deformed
between the outer peripheral surface 134 of the partition member
13b and the inner peripheral surface 131a of the peripheral wall
131 of the movable member 13a, thus providing sealing between the
control pressure chamber 13c and the swash plate chamber 33.
Accordingly, the O-rings 51a, 51b secures sealing between the
control pressure chamber 13c and the swash plate chamber 33.
[0071] Referring to FIG. 4, X1 indicates a first slide area of the
inner peripheral surface 131a of the movable member 13a with which
the O-ring 51b in the second annular groove 134a formed in the
outer peripheral surface 134 of the partition member 13b is in
sliding contact when the movable member 13a slides on the second
small diameter portion 30b of the movable member 13a along the axis
O of the drive shaft 3. In addition, X2 indicates a second slide
area of the outer peripheral surface 300 of the second small
diameter portion 30b with which the O-ring 51a mounted in the
movable member 13a is in sliding contact.
[0072] The inner peripheral surface 131a of the peripheral wall 131
has a sloped portion 135 which forms part of the first slide area
X1. The diameter of the sloped portion 135 is increased linearly
rearwardly of the peripheral wall 130. As shown in FIG. 4, the
movable member 13a has a first inner diameter L1 in the region
frontward of the sloped portion 135 and a second inner diameter L2
in the region rearward of the sloped portion 135 that is greater
than the first inner diameter L1.
[0073] When the movable member 13a slides rearward on the second
small diameter portion 30b of the drive shaft body 30 along the
axis O to a position where the partition member 13b is located
frontward of the sloped portion 135 in the first slide area X1, as
shown in FIG. 5, a first clearance S1 is formed between the outer
peripheral surface 134 of the partition member 13b and the inner
peripheral surface 131a of the peripheral wall 131. When the
movable member 13a slides rearward on the second small diameter
portion 30b of the drive shaft body 30 along the axis O to a
position where the partition member 13b is located rearward of the
sloped portion 135 in the first slide area X1, as shown in FIG. 6,
a second clearance S2 that is greater than the first clearance S1
is formed between the outer peripheral surface 134 of the partition
member 13b and the inner peripheral surface 131a of the peripheral
wall 131. In this actuator 13, the clearance between the outer
peripheral surface 134 of the partition member 13b and the inner
peripheral surface 131a of the peripheral wall 131 of the movable
member 13a is gradually increased from S1 to S2 in the first slide
area X1 with the movement of the movable member 13a relative to the
partition member 13b. In other words, the clearance between the
partition member 13b and the movable member 13a when the swash
plate 5 is at its minimum inclination angle position is greater
than the clearance between the partition member 13b and the movable
member 13a when the swash plate 5 is at its maximum inclination
angle position The clearance between the outer peripheral surface
300 of the second small diameter portion 30b and the movable member
13a remains constant irrespective of the movement of the movable
member 13a along the second slide area X2. It is to be noted that
the first clearance S1 and the second clearance S2 are shown in an
exaggerated manner in FIGS. 5 and 6.
[0074] As shown in FIGS. 1 and 2, the connecting arms 132 of the
movable member 13a are connected to the connecting portion 45c of
the ring plate 45 by the third pin 47c, so that the swash plate 5
is supported swingably about the axis M3 of the third pin 47c by
the movable member 13a. The first pin 47a and the third pin 47c are
disposed on radially opposite sides of the drive shaft body 30. In
other words, the arms 132 are connected to the ring plate 45 at
positions that are radially opposite sides of the hole 45b with
respect to the axis O.
[0075] An inclination angle reducing spring 44b is interposed
between the partition member 13b and the ring plate 45.
Specifically, the rear end of the inclination angle reducing spring
44b is mounted with the rear end thereof placed in contact with the
partition member 13b and the front end thereof placed in contact
with the ring plate 45, respectively. The inclination angle
reducing spring 44b urges the partition member 13b and the ring
plate 45 away from each other.
[0076] The axial passage 3b is formed in the second small diameter
portion 30b of the drive shaft body 30, extending in the direction
of the axis O. The rear end of the axial passage 3b is opened at
the rear end surface of the second small diameter portion 30b so as
to communicate with the pressure control chamber 31. The radial
passage 3c is connected to the front end of the axial passage 3b
and extends radially in the second small diameter portion 30b. With
the actuator 13 mounted on the drive shaft body 30, the radial
passage 3c is opened to the control pressure chamber 13c.
Consequently, the pressure control chamber 31 and the control
pressure chamber 13c are in communication with each other through
the axial passage 3b and the radial passage 3c.
[0077] As shown in FIG. 3, the control mechanism 15 includes a
bleeding passage 15a, a feeding passage 15b, a control valve 15c,
an orifice 15d, the axial passage 3b and the radial passage 3c.
[0078] The bleeding passage 15a is connected at the one end thereof
to the pressure control chamber 31 and at the other end thereof to
the second suction chamber 27b, so that the control pressure
chamber 13c, the pressure control chamber 31 and the second suction
chamber 27b are connected to one another through the bleeding
passage 15a, the axial passage 3b and the radial passage 3c. The
feeding passage 15b is connected at the one end thereof to the
pressure control chamber 31 and at the other end thereof to the
second discharge chamber 29b. Thus, the control pressure chamber
13c, the pressure control chamber 31 and the second discharge
chamber 29b are connected to one another through the feeding
passage 15b, the axial passage 3b and the radial passage 3c. The
orifice 15d is provided in the feeding passage 15b.
[0079] The control valve 15c is provided in the bleeding passage
15a and controls the opening of the bleeding passage 15a in
response to the pressure in the second suction chamber 27b.
[0080] The compressor has a pipe for connection between the suction
port 330 and the evaporator (not shown) and a pipe for connection
between the discharge port and the condenser (not shown). The
condenser is connected to the evaporator via pipes and the
expansion valve. The compressor, the evaporator, the expansion
valve and the condenser cooperate to form a refrigeration circuit
of a vehicle air conditioner. The evaporator, the expansion valve,
the condenser and the pipes are omitted from the illustration in
the drawings.
[0081] In the above-described compressor, the rotation of the swash
plate 5 driven by the drive shaft 3 causes the first and second
head portions 9a, 9b of each piston 9 to reciprocate in their
corresponding first and second cylinder bores 21a, 23a,
respectively. Accordingly, the volume of the first and second
compression chambers 53a, 53b is changed for compression of
refrigerant gas with the stroke length of the piston 9. In
accordance with the reciprocating movement of each piston 9,
suction phase in which the refrigerant gas is introduced into the
first and second compression chamber 53a, 53b, compression phase in
which refrigeration gas is compressed in the first and second
compression chambers 53a, 53b, and discharge phase in which the
compressed refrigerant gas is discharged out from the first and
second compression chambers 53a, 53b, take place repeatedly. The
refrigerant gas discharged into the first and second discharge
chambers 29a, 29b passes through the discharge passage and is
discharged to the condenser through the discharge port.
[0082] In the suction phase, the piston compression force acts on
the rotary assembly, which is formed by the swash plate 5, the ring
plate 45, the lug arm 49 and the first pin 47a, in the direction
that reduces the inclination angle of the swash plate 5. By
changing the inclination angle of the swash plate 5, the stroke
length of the piston 9 is changed and, accordingly, the
displacement of the compressor is varied.
[0083] In the control mechanism 15 shown in FIG. 3, when the
opening of the bleeding passage 15a is increased by the control
valve 15c, the pressures in the pressure control chamber 31 and the
control pressure chamber 13c become substantially the same as the
pressure in the second suction chamber 27b, so that the variable
pressure difference between the control pressure chamber 13c and
the swash plate chamber 33 becomes small. Accordingly, the pressure
P1 in the control pressure chamber 13c (FIGS. 8 and 9) acting on
the movable member 13a in the actuator 13 is decreased. The piston
compression force acting on the swash plate 5 causes the movable
member 13a to slide frontward along the second small diameter
portion 30b of the drive shaft body 30.
[0084] In this compressor, compression reaction force acting on the
swash plate 5 through the piston 9 urges the swash plate 5 in the
direction that reduces its inclination angle. The above compression
reaction force corresponds to the resultant force of the
compression reaction forces of the respective pistons acting on the
swash plate 5. The movable member 13a is pulled by the swash plate
5 through the arms 132 and the connecting portion 45c thereby to
move frontward along the axis O in the swash plate chamber 33 until
the ring plate 45 of the swash plate 5 is set in contact with the
rear end of the return spring 44a. Thus, the swash plate 5 is set
in contact with the rear end of the return spring 44a. With the
frontward movement of the movable member 13a in the swash plate
chamber 33, the swash plate 5 swings about the third axis M3
against the urging force of the return spring 44a. In addition, the
rear end of the lug arm 49 swings about the first axis M1 and the
front end of the lug arm 49 swings about the second axis M2, so
that the front end of the lug arm 49 moves towards the first flange
430 of the support member 43a. As a result, the swash plate 5
swings about the first axis M1 with the third axis M3 as the point
of application. The inclination angle of the swash plate 5 with
respect to an imaginary plane extending perpendicularly to the axis
O of the drive shaft is reduced, so that the stroke length of each
piston 9 is reduced. Accordingly, the discharge volume per rotation
of the drive shaft 3 and hence the displacement of the compressor
is reduced.
[0085] The centrifugal force generated by the rotation of the
weight 49a is also applied to the swash plate 5, so that the swash
plate 5 tends to be easily tilted in the direction that reduces its
inclination angle.
[0086] When the stroke length of the piston 9 is reduced with a
reduction of the inclination angle of the swash plate 5, the top
dead center of the second head portion 9b is shifted away from the
second valve forming plate 41. When the inclination angle of the
swash plate 5 is reduced close to zero, slight compression takes
place in the first compression chamber 53a with the discharge reed
valve slightly opened by refrigerant gas whereas no compression
takes place in the second compression chamber 53b and its
associated discharge reed valve remains closed accordingly.
[0087] The frontward sliding movement of the movable member 13a
along the second small diameter portion 30b in response to a
reduction of the pressure P1 in the control pressure chamber 13c
acting on the movable member 13a that is due to a reduced pressure
in the pressure control chamber 31 causes relative movement of the
partition member 13b rearward in the first slide area X1 along the
inner peripheral surface 131a of the peripheral wall 131. When the
swash plate 5 is at its minimum inclination angle position, the
partition member 13b is positioned rearward of the sloped portion
135 in the first slide area X1, as shown in FIG. 6. Then, the
movable member 13a is positioned in the front area of the second
slide area X2.
[0088] In the control mechanism 15 shown in FIG. 3, when the
opening of the bleeding passage 15a is reduced by the control valve
15c, the pressure in the pressure control chamber 31 is increased
by the pressure of refrigerant gas in the second discharge chamber
29b and the pressure in the control pressure chamber 13c is
increased, accordingly. The variable pressure difference between
the control pressure chamber 13c and the swash plate chamber 33
becomes large, so that the pressure P1 in the control pressure
chamber 13c acting on the movable member 13a is increased. The
movable member 13a moves rearward along the second small diameter
portion 30b against the piston compression force acting on the
swash plate 5 from the position shown in FIG. 1 to the position in
the second recess 23c shown in FIG. 2. The control mechanism 15
controls the pressure in the control pressure chamber 13c.
[0089] The swash plate 5 is pulled rearward by the movable member
13a through the arms 132 and the connecting portion 45c against the
urging force of the inclination angle reducing spring 44b.
Accordingly, the swash plate 5 swings about the third axis M3 in
the direction that increases its inclination angle 5. The rear end
of the lug arm 49 swings about the first axis M1 and the front end
of the lug arm 49 swings about the second axis M2 in the direction
that increases the inclination angle of the swash plate 5, so that
the front end of the lug arm 49 moves rearward away from the first
flange 430 of the first support member 43a. As a result, the swash
plate 5 swings about the first axis M1 with the third axis M3 as
the point of application in the direction that is reverse to the
direction that reduces the inclination angle of the swash plate 5.
In other words, the control pressure chamber 13c moves the movable
member 13a in a direction that increases the inclination angle with
an increase of the pressure in the control pressure chamber 13c.
The inclination angle of the swash plate 5 is thus increased and
the stroke length of each piston 9 is increased. Accordingly, the
discharge volume per rotation of the drive shaft 3 and hence the
displacement of the compressor is increased. The movable member 13a
is movable in the direction of the axis O on the drive shaft 3 and
the partition member 13b to change the inclination angle of the
swash plate 5.
[0090] The rearward movement of the movable member 13a along the
second small diameter portion 30b by the increased pressure P1 in
the control pressure chamber 13c causes frontward movement of the
partition member 13b relative to the movable member 13a in the
first slide area X1. When the inclination angle of the swash plate
5 becomes maximum, the partition member 13b is positioned frontward
of the sloped portion 135 in the first slide area X1, as shown in
FIG. 5, meanwhile the movable member 13a is positioned in the rear
part of the second slide area X2.
[0091] In changing the displacement of the compressor by changing
the inclination angle of the swash plate 5, the movable member 13a
of the actuator 13 moves slidably on the second small diameter
portion 30b of the drive shaft body 30 along the axis O. With the
slidable movement of the movable member 13a, the O-rings 51a, 51b
are elastically deformed between the outer peripheral surface 300
of the second small diameter portion 30b and the movable member 13a
and between the partition member 13b and the inner peripheral
surface 131a of the peripheral wall 131, respectively, which causes
resistance against the sliding movement the movable member 13a
along the axis O. In increasing the displacement of the compressor
by increasing the inclination angle of the swash plate 5, the
movable member 13a needs to slide against the resistance caused by
the O-rings 51a, 51b (hereinafter referred to as the slide
resistance R3), so that the pressure P1 in the control pressure
chamber 13c acting on the movable member 13a needs to be strong
enough to overcome the slide resistance R3. In the compressor of
the illustrated embodiment, the return spring 44a urges the
actuator 13 through the swash plate 5 in the direction that
increases the inclination angle of the swash plate 5. As the
inclination angle of the swash plate 5 is reduced with a decrease
of the pressure in the control pressure chamber 13c, the actuator
13 is urged by the return spring 44a through the swash plate 5 in
the direction that increases the inclination angle of the swash
plate 5. The return spring 44a ensures the movable member 13a to
move slidably in the direction that increases the inclination angle
of the swash plate 5 against the slide resistance R3.
[0092] Referring to FIG. 7, there is shown a compressor according
to an example for comparison with the compressor of the present
embodiment in which no sloped portion such as 135 is formed in the
inner peripheral surface 131a of the peripheral wall 131.
Specifically, the inner diameter of the movable member 13a in the
example remains constant at L1. As with the compressor of the first
embodiment, the clearance formed between the outer peripheral
surface 300 of the second small diameter portion 30b and the
movable member 13a remains constant irrespective of the position of
the movable member 13a in the second slide area X2. The rest of the
configuration of the compressor according to the comparison example
is substantially the same as the compressor according to the first
embodiment. Like parts or elements are designated by like reference
numerals and the description thereof will not be reiterated.
[0093] In the compressor of the comparison example having such
configuration, the first clearance S1 formed between the outer
peripheral surface 134 of the partition member 13b and the inner
peripheral surface 131a of the peripheral wall 131 remains constant
irrespective of the position of the partition member 13b relative
to the movable member 13a in the first slide area X1. In other
words, the clearance formed between the outer peripheral surface
134 and the inner peripheral surface 131a remains constant at the
first clearance S1 when the swash plate 5 is at its maximum
inclination angle position or at its minimum inclination angle
position. In addition, the clearance formed between the second
small diameter portion 30b and the movable member 13a remains
constant irrespective of the change in the pressure P1 in the
control chamber, or irrespective of the inclination angle of the
swash plate 5.
[0094] Referring to FIGS. 8 and 9, R1 represents the sum of the
resistance by elastic deformation of the O-ring 51a that is
determined by the clearance between the outer peripheral surface
300 of the second small diameter portion 30b and the movable member
13a and the resistance by elastic deformation of the O-ring 51b
that is determined by the clearance between the outer peripheral
surface 134 of the partition member 13b and the inner peripheral
surface 131a of the peripheral wall 131 of the movable member 13a.
The resistance R1 is variable in accordance with the clearance. R2
represents the sum of the resistances caused by elastic deformation
of the O-rings 51a, 51b which is increased with an increase of the
pressure P1 in the control pressure chamber. As indicated in the
chart of FIG. 8, the slide resistance R3 is resultant force of the
resistance R1 and the resistance R2. The pressure P1 in the control
pressure chamber 13c acting on the movable member 13a is also shown
in the charts of FIGS. 8 and 9.
[0095] In the compressor of the comparison example, the clearance
between the outer peripheral surface 134 and the inner peripheral
surface 131a and the clearance between the second small diameter
portion 30b and the movable member 13a remain constant,
respectively, irrespective of the inclination angle of the swash
plate 5. As indicated in FIG. 8, the resistance R1 remains constant
irrespective of the pressure P1 in the control pressure chamber
13c. An increase of the pressure P1 in the control pressure chamber
13c increases the resistance R2. In the compressor of the
comparison example, the slide resistance R3 increases from a point
corresponding to the resistance R1 with an increase of the pressure
P1 in the control pressure chamber 13c. When the pressure P1 in the
control pressure chamber 13c acting on the movable member 13a is
small and the swash plate 5 is at its minimum inclination angle
position, the slide resistance R3 becomes large relative to the
pressure P1 in the control pressure chamber 13c. In the compressor
of the comparison example, therefore, the sliding movement of the
movable member 13a along axis O on the second small diameter
portion 30b becomes difficult when the pressure P1 in the control
pressure chamber 13c is reduced. This makes it difficult for the
swash plate 5 to increase its inclination angle from its minimum
angle position, which causes poor controlling of the displacement
of the compressor.
[0096] According to the compressor of the first embodiment in which
the sloped portion 135 is formed in the peripheral wall 131, the
portion of the inner peripheral surface 131a having the first inner
diameter L1 is formed frontward of the sloped portion 135 and the
portion having the second inner diameter L2 rearward of the sloped
portion 135 in the movable member 13a. Consequently, when the
pressure P1 in the control pressure chamber 13c is increase to
position the partition member 13b frontward of the sloped portion
135 in the first slide movement area X1, as shown in FIG. 5, the
first clearance S1 is formed between the outer peripheral surface
134 and the inner peripheral surface 131a, as with the comparison
example of the compressor. When the pressure P1 in the control
pressure chamber 13c is reduced to position the partition member
13b rearward of the sloped portion 135 in the first slide area X1,
the second clearance S2 that is greater than the first clearance S1
is formed between the outer peripheral surface 134 and the inner
peripheral surface 131a, as shown in FIG. 6.
[0097] In the compressor of the first embodiment, the clearance
between the outer peripheral surface 134 and the inner peripheral
surface 131a becomes the first clearance S1 at the maximum
inclination angle of the swash plate 5 and the second clearance S2
at the minimum inclination angle of the swash plate 5,
respectively. Meanwhile, the clearance between the outer peripheral
surface 300 of the second small diameter portion 30b and the
movable member 13a remains constant irrespective of the inclination
angle of the swash plate 5 in the compressor of the first
embodiment, as well as the compressor of the comparison
example.
[0098] In the compressor of the first embodiment in which the
clearance between the outer peripheral surface 134 and the inner
peripheral surface 131a is increased from the first clearance S1 to
the second clearance S2, the elastic deformation of the O-ring 51b
is smaller when the pressure P1 in the control chamber is low than
when the pressure P1 is high. When the pressure P1 in the control
pressure chamber 13c is low and the clearance between the outer
peripheral surface 134 and the inner peripheral surface 131a is
large, the elastic deformation of the O-ring 51b is smaller, so
that the resistance R1 may be reduced. Although the slide
resistance R3 is increased in accordance with an increase of the
pressure P1 in the compressor of the first embodiment, the slide
resistance R3 of the first embodiment is smaller than that of the
compressor of the comparison example because the resistance R1 of
the compressor of the first embodiment is smaller than that of the
compressor of the comparison example.
[0099] In the compressor of the first embodiment, when the swash
plate 5 is at its minimum inclination angle, or when the pressure
P1 in the control pressure chamber 13c acting on the movable member
13a is small, the slide resistance R3 may be reduced to a
relatively low level for the pressure P1 in the control pressure
chamber 13c. This allows the movable member 13a to slide easily on
the second small diameter portion 30b along the axis O when the
pressure in control pressure chamber 13c is low. Accordingly, the
compressor of the first embodiment permits increasing the
inclination angle of the swash plate 5 from its minimum angle
easily.
[0100] Therefore, the compressor of the first embodiment may
achieve great controllability.
[0101] Furthermore, in the compressor of the present embodiment in
which the inner peripheral surface 131a of the peripheral wall 131
is formed with the sloped portion 135, the clearance only between
the outer peripheral surface 134 of the partition member 13b and
the inner peripheral surface 131a of the peripheral wall 131 is
variable between from the first clearance S1 and the second
clearance S2 with a change in the inclination angle of the swash
plate 5. Thus, the production of the compressor may be simplified,
as compared with the case of a compressor in which the actuator 13
is configured so that the clearance between the outer peripheral
surface 300 of the second small diameter portion 30b and the inner
peripheral surface of the movable member 13a, as well as the
clearance between the outer peripheral surface 134 and the inner
peripheral surface 131a, are variable. In addition, in the
compressor in which the partition member 13b has a diameter greater
than that of the drive shaft body 30 and is fixedly mounted on the
second small diameter portion 30b of the drive shaft body 30, the
O-ring 51b that is mounted in the partition member 13b has a
diameter greater than that of the O-ring 51a which is set in
sliding contact with the peripheral surface of the second small
diameter portion 30b of the drive shaft body 30. Such configuration
permits effectively reducing the resistance R1 by reducing the
elastic deformation of the O-ring 51b when the pressure P1 in the
control pressure chamber is reduced and the swash plate 5 is at its
minimum inclination angle accordingly, as compared with a case in
which elastic deformation of only the O-ring 51a is reduced. Thus,
the compressor of the present embodiment permits reducing the slide
resistance R3 effectively when the pressure P1 in the control
pressure chamber 13c acting on the movable member 13a is at a low
level.
[0102] Referring to FIG. 10, there is shown a compressor according
to a second embodiment of the present invention in which a sloped
portion 136 is formed in the inner peripheral surface 131a of the
peripheral wall 131 of the actuator 13. As with the sloped portion
135 of the first embodiment, the sloped portion 136 also increases
its diameter linearly toward the rear of the peripheral wall 131.
In the compressor of the second embodiment, the sloped portion 136
is formed extending substantially over the entire length of first
slide area X1. The rest of the configuration of the compressor
according to the second embodiment is substantially the same as the
first embodiment.
[0103] Referring to FIG. 11, there is shown a compressor according
to a third embodiment in which a sloped portion 137 is formed in
the inner peripheral surface 131a of the peripheral wall 131 of the
actuator 13. As with the first diameter increasing portion 135 of
the first embodiment, the sloped portion 137 forms part of the
first slide area X1, similarly to the sloped portion 135 of the
first embodiment. Unlike the first and sloped portions 135, 136,
the sloped portion 137 is formed with a curved convex surface.
Though not shown in the drawing, the sloped 137 may be formed
extending substantially over the entire length of the entire first
slide area X1 may be formed by the sloped portion 137. The rest of
the configuration of the compressor according to the third
embodiment is substantially the same as the first embodiment.
[0104] The compressors of the second and third embodiments offer
substantially the same effects as the first embodiment. Especially,
in the compressor of the second embodiment in which the sloped
portion 136 is formed extending substantially the entire length of
the first slide area X1, the clearance between the outer peripheral
surface 134 and the inner peripheral surface 131a may be varied
more precisely in the area between the first clearance S1 and the
second clearance S2.
[0105] The following will describe a compressor according to a
fourth embodiment of the present invention with reference to the
FIG. 12. Unlike the first, second and third embodiments in which
the first, second and sloped portions 135, 136, 137 are formed in
the inner peripheral surface 131a of the peripheral wall 131,
respectively, the compressor of the fourth embodiment has a sloped
portion 301 that is formed in the outer peripheral surface 300 of
the second small diameter portion 30b. The sloped portion 301 is
formed to cover part of the second slide area X2. The sloped
portion 301 increases its diameter linearly toward the rear end of
the sloped portion 301. Part of the second small diameter portion
30b disposed frontward of the fourth diameter expansion portion 301
is formed with an outer diameter L3 and part of the second small
diameter portion 30b disposed rearward of the sloped portion 301 is
formed with an outer diameter L4 that is greater than the outer
diameter L3.
[0106] As shown in FIG. 13, when the movable member 13a is
positioned rearward of the sloped portion 301 in the second slide
area X2 with the sliding movement of the movable member 13a on the
second small diameter portion 30b along the axis O, a third
clearance S3 is formed between the outer peripheral surface 300 of
the second small diameter portion 30b and the movable member 13a,
which increases gradually to a fourth clearance S4 with the
frontward movement of the movable member 13a along the sloped
portion 301 in the second the slide area X2. For the sake of the
description, the third and fourth spaced distances S3, S4 are
illustrated in an exaggerated manner in FIGS. 13 and 14.
[0107] Unlike the compressor of the first embodiment in which the
sloped portion 135 is formed in the inner peripheral surface 131a
of the peripheral wall 131, no sloped portion such as 135 is formed
in the inner peripheral surface 131a of the peripheral wall 131 of
the compressor of the fourth embodiment, so that the inner diameter
of the movable member 13a remains constant at the first inner
diameter L1, as shown in FIG. 12. Accordingly, the clearance
between outer peripheral surface 134 of the partition member 13b
and the inner peripheral surface 131a of the peripheral wall 131
remains constant at the first clearance S1. The rest of the
configuration of the compressor according to the fourth embodiment
is substantially the same as the first embodiment.
[0108] In this compressor, an increase of the pressure P1 in the
control pressure chamber 13c moves the movable member 13a to a
position rearward of the sloped portion 301 in the second slide
area X2 where the third clearance S3 is formed between the outer
peripheral surface 300 of the second small diameter portion 30b and
the movable member 13a when the swash plate 5 is at its maximum
inclination angle. A reduction of the pressure P1 in the control
pressure chamber 13c moves the movable member 13a to a position
frontward of the sloped portion 301 in the second slide area X2
where the fourth clearance S4 is formed between the outer
peripheral surface 300 of the second small diameter portion 30b and
the movable member 13a when the swash plate 5 is at its minimum
inclination angle.
[0109] In the structure in which the clearance between the outer
peripheral surface 300 of the second small diameter portion 30b and
the movable member 13a is variable between the third clearance
distance S3 and the fourth clearance S4, smaller elastic
deformation of the O-ring 51b occurs when the pressure P1 in the
control pressure chamber 13c is reduced, as compared with elastic
deformation of the O-ring 51b when the pressure P1 in the control
pressure chamber is increased. As with the compressor of the first
embodiment, the compressor of the fourth embodiment permits
reducing the slide resistance R3 relative to the pressure P1 in the
control pressure chamber 13c acting on the movable member 13a when
the swash plate 5 is at its minimum inclination angle, as with the
compressor of the first embodiment. Accordingly, the compressor of
the fourth embodiment also permits easily increasing the
inclination angle of the swash plate 5 from its minimum angle. The
rest of the configuration of the compressor according to the fourth
embodiment is substantially the same as the first embodiment.
[0110] Referring to FIG. 15, there is shown a compressor according
to a fifth embodiment in which a sloped portion 302 is formed in
the outer peripheral surface 300 of the second small diameter
portion 30b of the drive shaft body 30. As with the sloped portion
301 of the fourth embodiment, the sloped portion 302 increases its
diameter linearly toward the rear end of the sloped portion 302.
The sloped portion 302 is formed extending the entire length of the
second slide area X2. The rest of the configuration of the
compressor of the fifth embodiment is substantially the same as the
first and fourth embodiments.
[0111] Referring to FIG. 16, there is shown a compressor according
to a sixth embodiment in which a sloped portion 303 is formed in
the outer peripheral surface 300 of the second small diameter
portion 30b of the drive shaft body 302. As with the
above-described sloped portion 301, the sloped portion 303 is
formed so as to cover part of the second slide area X2. Unlike the
sloped portions 301, 302, the sloped portion 303 is formed with a
curved convex surface. The entire second slide area X2 may be
formed by the sloped portion 303. The rest of the configuration of
the compressor according to the sixth embodiment is substantially
the same as the first and fourth embodiments.
[0112] The compressors of the fifth and sixth embodiments offer
substantially the same effects as the first and fourth embodiments.
Especially, in the compressor of the fifth embodiment in which the
entire second slide area X2 is formed by the sloped portion 302, so
that the clearance between the outer peripheral surface 300 of the
second small diameter portion 30b and the movable member 13a may be
varied more precisely between the third clearance S3 and the fourth
clearance S4.
[0113] The present invention is not limited to the above-described
first to sixth embodiments, but may be modified in various manners
within the scope of the present invention, as exemplified
below.
[0114] The compressor may have a configuration in which one of the
first, second and third embodiments may be combined with one of the
fourth, fifth and six embodiments. In this case, the elastic
deformation of both of the O-rings 51a, 51b when the pressure P1 in
the control pressure chamber is small may be reduced, which permits
further reducing the slide resistance R3 for the pressure P1 in the
control pressure chamber 13c acting on the movable member 13a when
the swash plate 5 is at its minimum inclination angle.
[0115] The present invention is applicable to a single head piston
type swash plate compressor with variable displacement
capability.
[0116] The actuator 13 and the link mechanism 7 may be disposed
frontward and rearward of the swash plate 5, respectively, in the
swash plate chamber 33.
[0117] In the control mechanism 15, the control valve 15c and the
orifice 15d may be disposed in the feeding passage 15b and in the
bleeding passage 15a, respectively. In this case, the control valve
15c controls the opening of the feeding passage 15b. Because the
pressure P1 in the control pressure chamber may be quickly
increased by the pressure of the refrigerant gas in the second
discharge chamber 29b, the displacement of the compressor may be
increased quickly.
[0118] The control valve 15c may be replaced with a flow rate
control valve that controls the opening the bleeding passage 15a or
the feeding passage 15b. In this case, a first pressure monitoring
point is set in the discharge pressure region in the refrigeration
circuit and a second pressure monitoring point is set at a point
that is downstream of the first pressure monitoring point with
respect to the refrigerant gas flowing direction and where the
pressure of the refrigerant gas is lower than the first pressure
monitoring point. The flow rate control valve controls the opening
of the bleeding passage 15a or the feeding passage 15b based on the
pressure difference between the first pressure monitoring point and
the second pressure monitoring point.
[0119] The compressor of the present embodiment is applicable to
any type of air conditioner.
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