U.S. patent application number 14/917820 was filed with the patent office on 2016-08-04 for variable displacement swash plate type 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 Kazunari HONDA, Hiroyuki NAKAIMA, Masaki OTA, Takahiro SUZUKI, Shinya YAMAMOTO, Hideharu YAMASHITA, Yusuke YAMAZAKI.
Application Number | 20160222953 14/917820 |
Document ID | / |
Family ID | 52665738 |
Filed Date | 2016-08-04 |
United States Patent
Application |
20160222953 |
Kind Code |
A1 |
YAMAMOTO; Shinya ; et
al. |
August 4, 2016 |
VARIABLE DISPLACEMENT SWASH PLATE TYPE COMPRESSOR
Abstract
A variable displacement swash plate type compressor includes an
actuator having a movable body and a control pressure chamber. An
acting portion capable of pressing a swash plate by the pressure in
the control pressure chamber is formed at the movable body, and an
acted portion that abuts on and is pressed by the acting portion is
formed at the swash plate. The acting portion abuts on the acted
portion at an operative position, which moves in accordance with
the change of an inclination angle of the swash plate. A
top-dead-center corresponding portion is defined in the swash
plate, and the operative position when the inclination angle is
maximum is closer to the top-dead-center corresponding portion as
compared to the operative position when the inclination angle is
minimum.
Inventors: |
YAMAMOTO; Shinya;
(Kariya-shi, JP) ; YAMAZAKI; Yusuke; (Kariya-shi,
JP) ; SUZUKI; Takahiro; (Kariya-shi, JP) ;
HONDA; Kazunari; (Kariya-shi, JP) ; OTA; Masaki;
(Kariya-shi, JP) ; NAKAIMA; Hiroyuki; (Kariya-shi,
JP) ; YAMASHITA; Hideharu; (Kariya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOYOTA JIDOSHOKKI |
Aichi |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Aichi-ken
JP
|
Family ID: |
52665738 |
Appl. No.: |
14/917820 |
Filed: |
September 10, 2014 |
PCT Filed: |
September 10, 2014 |
PCT NO: |
PCT/JP2014/073985 |
371 Date: |
March 9, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 27/1072 20130101;
F04B 27/0878 20130101; F04B 27/1045 20130101; F04B 27/18 20130101;
F04B 27/1009 20130101; F04B 27/1063 20130101; F04B 49/225
20130101 |
International
Class: |
F04B 27/18 20060101
F04B027/18; F04B 27/08 20060101 F04B027/08; F04B 49/22 20060101
F04B049/22; F04B 27/10 20060101 F04B027/10 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2013 |
JP |
2013-187967 |
Claims
1. A variable displacement swash plate type compressor comprising:
a housing in which a swash plate chamber and a cylinder bore are
formed; a drive shaft that is rotatably supported by the housing; a
swash plate that is rotatable in the swash plate chamber by
rotation of the drive shaft; a link mechanism that is provided
between the drive shaft and the swash plate and permits change of
an inclination angle of the swash plate with respect to a direction
perpendicular to a driving axis of the drive shaft; a piston that
is reciprocally accommodated in the cylinder bore; a conversion
mechanism that reciprocates the piston in the cylinder bore at a
stroke corresponding to the inclination angle by rotation of the
swash plate; an actuator capable of changing the inclination angle;
and a control mechanism that controls the actuator, wherein the
link mechanism has a lug member that is fixed to the drive shaft in
the swash plate chamber and a transmission member that transmits
rotation of the lug member to the swash plate, the actuator has the
lug member, a movable body that is rotatable integrally with the
swash plate and is capable of changing the inclination angle by
moving in the direction of the driving axis, and a control pressure
chamber that is defined by the lug member and the movable body and
moves the movable body by changing its internal pressure by the
control mechanism, an acting portion that is capable of pressing
the swash plate by the pressure in the control pressure chamber is
formed at the movable body, an acted portion that abuts on and is
pressed by the acting portion is formed at the swash plate, the
acting portion abuts on the acted portion at an operative position,
the operative position moves in accordance with the change of the
inclination angle, a top-dead-center corresponding portion for
positioning the piston at its top dead center is defined in the
swash plate, and the operative position when the inclination angle
is maximum is closer to the top-dead-center corresponding portion
as compared to the operative position when the inclination angle is
minimum.
2. The variable displacement swash plate type compressor according
to claim 1, wherein the drive shaft is inserted through the movable
body, and the movable body is capable of being fitted to the lug
member.
3. The variable displacement swash plate type compressor according
to claim 2, wherein the movable body has a movable cylindrical
portion that is formed into a cylindrical shape and coaxial with
the driving axis, and the lug member has a fixed cylindrical
portion that is formed into a cylindrical shape and coaxial with
the driving axis at an outer circumferential side of the movable
cylindrical portion to thereby provide the control pressure chamber
in the movable cylindrical portion.
4. The variable displacement swash plate type compressor according
to claim 3, wherein a first seal member that seals the control
pressure chamber is provided between the movable cylindrical
portion and the drive shaft, and a second seal member that seals
the control pressure chamber is provided between the movable
cylindrical portion and the fixed cylindrical portion.
5. The variable displacement swash plate type compressor according
to claim 3, wherein a thrust bearing that receives a thrust force
which acts on the piston is provided between the housing and the
lug member, and the movable cylindrical portion is smaller in
diameter than the thrust bearing and capable of advancing to an
inner side of the thrust bearing.
6. The variable displacement swash plate type compressor according
to claim 1, wherein the acting portion comes into point-contact or
line-contact with the acted portion at the operative position.
7. The variable displacement swash plate type compressor according
to claim 6, wherein the acting portion and the acted portion are
located eccentrically toward the top-dead-center corresponding
portion from the driving axis, and the operative position moves
toward the driving axis as the inclination angle decreases.
8. The variable displacement swash plate type compressor according
to claim 7, wherein the acting portion has an acting surface that
extends in the direction perpendicular to the driving axis, and the
acted portion has a protrusion that protrudes from the swash plate
and abuts on the acting surface.
9. The variable displacement swash plate type compressor according
to claim 7, wherein the movable body has a movable cylindrical
portion that is formed into a cylindrical shape and coaxial with
the driving axis, and the acting portion protrudes from the movable
cylindrical portion toward the top-dead-center corresponding
portion.
10. The variable displacement swash plate type compressor according
to claim 1, wherein the swash plate has a swash plate main body
that is formed with an insertion hole, through which the drive
shaft is inserted, and the acted portion that is integrally formed
with the swash plate main body.
11. The variable displacement swash plate type compressor according
to claim 1, wherein the swash plate has a swash plate main body
that is formed with an insertion hole, through which the drive
shaft is inserted, and the acted portion that is fixed to the swash
plate main body.
12. The variable displacement swash plate type compressor according
to claim 1, wherein a suction chamber and a discharge chamber are
formed in the housing, and the suction chamber and the swash plate
chamber communicate with each other.
13. The variable displacement swash plate type compressor according
to claim 12, wherein the control mechanism has a control passage
that provides communication between the control pressure chamber
and the suction chamber and/or the discharge chamber and a control
valve that is capable of regulating an opening degree of the
control passage, and at least a part of the control passage is
formed in the drive shaft.
14. The variable displacement swash plate type compressor according
to claim 13, wherein a pressure regulation chamber that
communicates with the control pressure chamber through the control
passage and allows a pressure therein to be changed by the control
valve is formed between the housing and one end of the drive shaft,
and a third seal member that seals the pressure regulation chamber
is provided between the housing and the drive shaft.
Description
TECHNICAL FIELD
[0001] The present invention relates to a variable displacement
swash plate type compressor.
BACKGROUND ART
[0002] Patent Literature 1 discloses a conventional variable
displacement swash plate type compressor (hereinafter referred to
as a compressor). This compressor comprises a housing, a drive
shaft, a swash plate, a link mechanism, a plurality of pistons, a
conversion mechanism, and a capacity control mechanism.
[0003] In the housing, a suction chamber, a discharge chamber, a
swash plate chamber and a plurality of cylinder bores are formed.
The drive shaft is rotatably supported by the housing. The swash
plate is rotatable in the swash plate chamber by rotation of the
drive shaft. The link mechanism is provided between the drive shaft
and the swash plate and permits change of an inclination angle of
the swash plate with respect to a direction perpendicular to a
driving axis of the drive shaft. The link mechanism has a lug
member and a transmission member. The lug member is fixed to the
drive shaft in the swash plate chamber. The transmission member is
provided integrally with the swash plate in the swash plate
chamber, and transmits rotation of the lug member to the swash
plate. The pistons are reciprocally accommodated in respective
cylinder bores. The conversion mechanism reciprocates the pistons
in the cylinder bores at a stroke corresponding to the inclination
angle by rotation of the swash plate. The capacity control
mechanism has a supply passage, a bleed passage and a control
valve. The supply passage provides communication between the
discharge chamber and the swash plate chamber. The bleed passage
provides communication between the swash plate chamber and the
suction chamber. The control valve is capable of changing the
pressure in the swash plate chamber by regulating an opening degree
of the supply passage.
[0004] In the compressor, when the control valve increases the
pressure in the swash plate chamber, the inclination angle becomes
small and the stroke of the pistons decreases. Therefore, a
compression capacity per rotation of the drive shaft becomes small.
On the other hand, when the control valve decreases the pressure in
the swash plate chamber, the inclination angle of the swash plate
becomes large, and the stroke of the pistons increases. Therefore,
the compression capacity per rotation of the drive shaft becomes
large. In this manner, in this compressor, the discharge capacity
of refrigerant is changeable in response to the driving conditions
of a vehicle or the like on which the compressor is mounted.
[0005] However, in the case of changing the inclination angle by
changing the pressure in the swash plate chamber like this
compressor, it is necessary to provide a sufficient amount of
refrigerant in the swash plate chamber in order to change the
inclination angle. Therefore, the size of the compressor tends to
be increased due to a large swash plate chamber.
[0006] Furthermore, in this compressor, it is inevitable that
blow-by gas having a high pressure flows into the swash plate
chamber. Furthermore, in this compressor, when the outside air
temperature drops, the refrigerant in the swash plate chamber is
likely to condense and liquid accumulation occurs in the swash
plate chamber. For these reasons, in this compressor, it is
difficult to change the inclination angle suitably.
[0007] Therefore, a compressor as disclosed in Patent Literature 2
has also been proposed. This compressor includes an actuator that
is capable of changing an inclination angle, and a control
mechanism that controls the actuator.
[0008] Specifically, the actuator has a lug member, a movable body
that engages with a swash plate so as to be rotatable integrally
therewith and is movable in the direction of a driving axis to
change the inclination angle, and a control pressure chamber that
is defined by the lug member and the movable body and moves the
movable body by its internal pressure. The control mechanism has a
control passage and a control valve. The control passage has a
variable pressure passage that communicates with the control
pressure chamber, a low pressure passage that communicates with a
suction chamber and a swash plate chamber, and a high pressure
passage that communicates with a discharge chamber. A part of the
variable pressure passage is formed in a drive shaft. The control
valve regulates an opening degree of the variable pressure passage,
the low pressure passage and the high pressure passage. In other
words, the control valve allows the variable pressure passage to
communicate with the low pressure passage or the high pressure
passage.
[0009] In this compressor, when the control valve allows the
variable pressure passage to communicate with the high pressure
passage, the pressure in the control pressure chamber becomes
higher than that of the swash plate chamber. Thereby, the movable
body of the actuator moves away from the lug member, and the
inclination angle decreases. Therefore, the stroke of the pistons
decreases and the discharge capacity becomes small. On the other
hand, when the control valve allows the variable pressure passage
to communicate with the low pressure passage, the pressure in the
control pressure chamber becomes as low as that of the swash plate
chamber. Thereby, the movable body of the actuator approaches the
lug member, and the inclination angle increases. Therefore, the
stroke of the pistons increases and the discharge capacity becomes
large.
[0010] Since this compressor is configured to change the pressure
in the control pressure chamber, which has a smaller volume than
the swash plate chamber, the amount of the refrigerant required to
change the inclination angle can be reduced as compared to the
compressor configured to change the pressure in the swash plate
chamber, and thereby downsizing can be realized.
[0011] Furthermore, since this compressor is configured to change
the inclination angle by changing the pressure in the control
pressure chamber, the blow-by gas flowing into the swash plate
chamber and the liquid accumulation in the swash plate chamber are
less likely to exert an adverse effect on the change of the
inclination angle.
CITATION LIST
Patent Literature
[0012] Patent Literature 1: Japanese Patent Laid-Open No.
2002-213350
[0013] Patent Literature 2: Japanese Patent Laid-Open No.
52-131204
SUMMARY OF INVENTION
Technical Problem
[0014] However, in the compressor described in Patent Literature 2
described above, when a plane determined by the driving axis and a
top-dead-center corresponding portion of the swash plate is defined
as a first imaginary plane, the movable body of the actuator
engages with the swash plate at a second imaginary plane that is
perpendicular to the first imaginary plane and includes the driving
axis. In addition, an operative position where the movable body
abuts on the hinge ball moves in parallel with the direction of the
driving axis as the inclination angle of the swash plate changes.
The same applies to an operative position where the hinge ball
abuts on the swash plate. That is, in this compressor, the distance
between the operative position and the driving axis does not change
even when the inclination angle of the swash plate changes.
[0015] Therefore, in this compressor, at the time of decreasing the
inclination angle, it is necessary to increase a differential
pressure between the swash plate chamber and the control pressure
chamber (hereinafter referred to as a variable differential
pressure) to thereby move the movable body by a larger thrust
force. That is, in this compressor, the load exerted on the movable
body increases as the inclination angle decreases. Therefore, in
this compressor, the amount of change in the variable differential
pressure when the inclination angle changes is large; therefore, it
is difficult to quickly change the inclination angle in response to
the driving conditions of a vehicle or the like, and
controllability is lowered.
[0016] Furthermore, in this compressor, since the distance between
the operative position and the driving axis does not change, a
stroke of the movable body in order to change the inclination angle
of the swash plate is long in the direction of the driving axis.
Consequently, it is inevitable to enlarge the compressor in the
axial length, and therefore, there is a concern about mountability
on a vehicle or the like.
[0017] The present invention has been made in the light of the
conventional circumstances described above, and an object of the
invention is to provide a variable displacement swash plate type
compressor capable of exhibiting high controllability and excellent
mountability.
Solution to Problem
[0018] A variable displacement swash plate type compressor of the
present invention comprises: a housing in which a swash plate
chamber and a cylinder bore are formed; a drive shaft that is
rotatably supported by the housing; a swash plate that is rotatable
in the swash plate chamber by rotation of the drive shaft; a link
mechanism that is provided between the drive shaft and the swash
plate and permits change of an inclination angle of the swash plate
with respect to a direction perpendicular to a driving axis of the
drive shaft; a piston that is reciprocally accommodated in the
cylinder bore; a conversion mechanism that reciprocates the piston
in the cylinder bore at a stroke corresponding to the inclination
angle by rotation of the swash plate; an actuator capable of
changing the inclination angle; and a control mechanism that
controls the actuator,
[0019] wherein the link mechanism has a lug member that is fixed to
the drive shaft in the swash plate chamber and a transmission
member that transmits rotation of the lug member to the swash
plate,
[0020] the actuator has the lug member, a movable body that is
rotatable integrally with the swash plate and is capable of
changing the inclination angle by moving in the direction of the
driving axis, and a control pressure chamber that is defined by the
lug member and the movable body and moves the movable body by
changing its internal pressure by the control mechanism,
[0021] an acting portion that is capable of pressing the swash
plate by the pressure in the control pressure chamber is formed at
the movable body,
[0022] an acted portion that abuts on and is pressed by the acting
portion is formed at the swash plate,
[0023] the acting portion abuts on the acted portion at an
operative position,
[0024] the operative position moves in accordance with the change
of the inclination angle,
[0025] a top-dead-center corresponding portion for positioning the
piston at its top dead center is defined in the swash plate,
and
[0026] the operative position when the inclination angle is maximum
is closer to the top-dead-center corresponding portion as compared
to the operative position when the inclination angle is
minimum.
[0027] In the compressor of the present invention, the transmission
member of the link mechanism transmits rotation of the lug member
to the swash plate. In addition, the operative position at which
the acting portion of the movable body abuts on the acted portion
of the swash plate moves in accordance with the change of the
inclination angle of the swash plate. Specifically, the operative
position when the inclination angle is maximum is closer to the
top-dead-center corresponding portion of the swash plate as
compared to the operative position when the inclination angle is
minimum.
[0028] Therefore, in this compressor, as compared with the case
where the operative position has a constant distance from the
driving axis even when the inclination angle of the swash plate
changes, it is possible to move the movable body without increasing
the variable differential pressure at the time of decreasing the
inclination angle so as to provide a large thrust force. That is,
in this compressor, it is possible to reduce the load exerted on
the movable body at the time of decreasing the inclination angle.
Consequently, in this compressor, the amount of change in the
variable differential pressure when the inclination angle changes
is small; therefore, it is easy to quickly change the inclination
angle in response to the driving conditions of a vehicle or the
like, and high controllability can be exhibited.
[0029] Furthermore, in this compressor, since the operative
position moves as described above in accordance with the change of
the inclination angle of the swash plate, the stroke of the movable
body in the direction of the driving axis can be reduced as
compared with the case where the operative position has a constant
distance from the driving axis, provided that the range of their
inclination angle is the same. This suppresses enlargement of the
compressor in the axial length.
[0030] Accordingly, the compressor of the present invention is
capable of exhibiting high controllability and excellent
mountability.
[0031] It is not impossible to employ such a configuration that,
for example, the acting portion is connected to the acted portion
with a connection pin etc. However, in this case, there is a risk
that the configuration of a connection portion changes the posture
of the movable body. In addition, because the number of components
increases, the configuration of the compressor is complicated and
manufacturing cost increases. In contrast, in the compressor of the
present invention, the movable body merely abuts directly on and
presses the swash plate to change the inclination angle of the
swash plate, and therefore, the posture of the movable body is less
likely to change. In addition, in this compressor, it is possible
to suppress complication of the configuration, and reduction in
manufacturing cost can be realized.
[0032] The control mechanism may have a control passage and a
control valve. The control passage may have a variable pressure
passage that communicates with the control pressure chamber, a low
pressure passage that communicates with a suction chamber or a
swash plate chamber, and a high pressure passage that communicates
with a discharge chamber.
[0033] It is preferable that the drive shaft is inserted through
the movable body, and the movable body is capable of being fitted
to the lug member. In this case, a space for allowing the movable
body to move in the direction of the driving axis can be suitably
provided between the lug member and the swash plate.
[0034] Furthermore, the movable body may have a movable cylindrical
portion that is formed into a cylindrical shape and coaxial with
the driving axis. It is preferable that the lug member has a fixed
cylindrical portion that is formed into a cylindrical shape and is
coaxial with the driving axis at an outer circumferential side of
the movable cylindrical portion to thereby provide the control
pressure chamber in the movable cylindrical portion. In this case,
by fitting the movable cylindrical portion into the fixed
cylindrical portion, the movable body can be fitted to the lug
member. Furthermore, since the control pressure chamber is provided
in the movable cylindrical portion by the fixed cylindrical
portion, the control pressure chamber can be suitably formed
between the lug member and the movable body.
[0035] Furthermore, in this case, a first seal member that seals
the control pressure chamber may be provided between the movable
cylindrical portion and the drive shaft. In addition, it is
preferable that a second seal member that seals the control
pressure chamber is provided between the movable cylindrical
portion and the fixed cylindrical portion. Thereby, hermeticity of
the control pressure chamber can be suitably ensured. Here, as the
first seal member and the second seal member, various seals can be
employed besides O-rings etc. The first seal member and the second
seal member may be of the same kind or different kinds.
[0036] A thrust bearing that receives a thrust force which acts on
the piston may be provided between the housing and the lug member.
In addition, it is preferable that the movable cylindrical portion
is smaller in diameter than the thrust bearing and capable of
advancing to an inner side of the thrust bearing.
[0037] In this case, it is possible for the thrust bearing to
suitably receive a suction reaction force which acts on the piston
during a suction phase and a compression reaction force which acts
on the piston during a compression phase. Furthermore, by allowing
the movable cylindrical portion to advance to the inner side of the
thrust bearing, even if the axial length of the compressor is
short, the space for allowing the movable body to move in the
direction of the driving axis can be sufficiently ensured.
[0038] In the compressor of the present invention, the acting
portion and the acted portion come into point-contact or
line-contact with each other at the operative position. In this
case, the contact area between the acting portion and the acted
portion can be made small. Here, the straight line on which the
operative position and the acted portion are brought into
line-contact is perpendicular to the first imaginary plane
determined by the top-dead-center corresponding portion of the
swash plate and the driving axis. Furthermore, when bringing the
acting portion into point-contact or line-contact with the acted
portion at the operative position, it is preferable that either one
of a portion in the acting portion where it abuts on the acted
portion and a portion in the acted portion where it abuts on the
acting portion is formed into a curved shape.
[0039] Furthermore, the position in the movable body where the
acting portion is formed and the position in the swash plate where
the acted portion is formed can be designed as appropriate. In
particular, in the compressor of the present invention, the acting
portion and the acted portion may be located eccentrically toward
the top-dead-center corresponding portion from the driving axis. It
is preferable that the operative position moves toward the driving
axis when the inclination angle decreases.
[0040] In this case, a space for allowing the movable body to move
in the direction of the driving axis is easily provided between the
lug member and the swash plate without disrupting the change of the
inclination angle. Therefore, in this compressor, it is possible to
increase the diameter of the actuator so as to quickly move the
movable body by a sufficient thrust force while suppressing
enlargement of the compressor in the axial length.
[0041] The acting portion may have an acting surface that extends
in the direction perpendicular to the driving axis. It is
preferable that the acted portion has a protrusion that protrudes
from the swash plate and abuts on the acting surface. In this case,
the acting portion and the acted portion can be suitably brought
into point-contact or line-contact with each other.
[0042] It is preferable that the acting portion protrudes from the
movable cylindrical portion toward the top-dead-center
corresponding portion. In this case, the acting portion easily
abuts on the acted portion.
[0043] It is preferable that the swash plate has a swash plate main
body that is formed with an insertion hole, through which the drive
shaft is inserted, and the acted portion that is integrally formed
with the swash plate main body. In this case, it is possible to
reduce the number of components in the compressor, facilitate
manufacturing, and reduce manufacturing cost.
[0044] It is also preferable that the swash plate has a swash plate
main body that is formed with an insertion hole, through which the
drive shaft is inserted, and the acted portion that is fixed to the
swash plate main body. In this case, it is possible to improve the
flexibility of design with respect to the swash plate main body and
the acted portion.
[0045] In the compressor of the present invention, a suction
chamber and a discharge chamber may be formed in the housing. It is
preferable that the suction chamber and the swash plate chamber
communicate with each other. In this case, the pressure in the
swash plate chamber can be made low as well as the suction
chamber.
[0046] Furthermore, the control mechanism may have a control
passage that provides communication between the control pressure
chamber and the suction chamber and/or the discharge chamber, and a
control valve that is capable of regulating an opening degree of
the control passage. It is preferable that at least a part of the
control passage is formed in the drive shaft. In this case, it is
possible to suitably change the pressure in the control pressure
chamber and suitably move the movable body while downsizing the
control mechanism.
[0047] A pressure regulation chamber that communicates with the
control pressure chamber through the control passage and allows a
pressure therein to be changed by the control valve may be formed
between the housing and one end of the drive shaft. It is
preferable that a third seal member that seals the pressure
regulation chamber is provided between the housing and the drive
shaft.
[0048] In this case, when the pressure in the pressure regulation
chamber is changed by the control valve, the control pressure
chamber moves the movable body. By the third seal member,
hermeticity of the pressure regulation chamber can be suitably
ensured. Here, as the third seal member, various seals can be
employed besides O-rings etc. as in the case of the first and
second seal members described above. Furthermore, the third seal
member may be of the same kind as or a different kind from the
first and second seal members.
Advantageous Effects of Invention
[0049] The compressor of the present invention is capable of
exhibiting high controllability and excellent mountability.
BRIEF DESCRIPTION OF DRAWINGS
[0050] FIG. 1 is a sectional view of a compressor according to
Embodiment 1 at the time of maximum displacement.
[0051] FIG. 2 is a schematic diagram showing a control mechanism of
the compressor according to Embodiment 1.
[0052] FIG. 3 is an enlarged sectional view of an essential part of
the compressor according to Embodiment 1, showing a rear end
portion of a drive shaft.
[0053] FIG. 4 is an enlarged sectional view of an essential part of
the compressor according to Embodiment 1, showing an actuator.
[0054] FIG. 5 is a front perspective view showing a swash plate of
the compressor according to Embodiment 1.
[0055] FIG. 6 is a sectional view of the compressor according to
Embodiment 1 at the time of minimum displacement.
[0056] FIG. 7A is an enlarged sectional view of an essential part
of the compressor according to Embodiment 1, showing an operative
position where an acting portion abuts on an acted portion when an
inclination angle of the swash plate is maximum.
[0057] FIG. 7B is an enlarged sectional view of an essential part
of the compressor according to Embodiment 1, showing the operative
position when the inclination angle is minimum.
[0058] FIG. 8 is a graph showing a relation between the inclination
angle and a variable differential pressure.
[0059] FIG. 9 is a schematic view of the compressor according to
Embodiment 1 and a compressor of a comparative example, showing a
difference in strokes of movable bodies.
[0060] FIG. 10 is a sectional view of a compressor according to
Embodiment 2 at the time of maximum displacement.
DESCRIPTION OF EMBODIMENTS
[0061] Hereinafter, Embodiments 1 and 2, which embody the present
invention, will be described with reference to the drawings. The
compressors of Embodiments 1 and 2 are variable displacement
single-head swash plate type compressors. These compressors are
both mounted on vehicles and constitute refrigeration circuits of
vehicle air-conditioning apparatus.
Embodiment 1
[0062] As shown in FIG. 1, the compressor of Embodiment 1 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 and
11b, an actuator 13, and a control mechanism 15 which is shown in
FIG. 2. In FIG. 1, the illustration of the swash plate 5 is
partially simplified for ease of explanation. The same applies to
FIGS. 6 and 10, which will be described later.
[0063] As shown in FIG. 1, the housing 1 has a front housing 17
that is located at a front side in the compressor, a rear housing
19 that is located at a rear side in the compressor, a cylinder
block 21 that is located between the front housing 17 and the rear
housing 19, and a valve unit 23.
[0064] The front housing 17 has a front wall 17a that extends in
the up-down direction of the compressor at the front side, and a
circumferential wall 17b that is integrated with the front wall 17a
and extends rearward from the front side of the compressor. By the
front wall 17a and the circumferential wall 17b, the front housing
17 is formed into a substantially cylindrical shape with a bottom.
Furthermore, by the front wall 17a and the circumferential wall
17b, a swash plate chamber 25 is formed in the front housing
17.
[0065] A boss 17c that protrudes frontward is formed on the front
wall 17a. A shaft seal device 27 is provided in the boss 17c.
Furthermore, a first shaft hole 17d that extends in the front-rear
direction of the compressor is formed in the boss 17c. A first
sliding bearing 29a is provided in the first shaft hole 17d.
[0066] An inlet port 250 that communicates with the swash plate
chamber 25 is formed through the circumferential wall 17b. Through
the inlet port 250, the swash plate chamber 25 is connected to an
evaporator, which is not illustrated.
[0067] A part of the control mechanism 15 is provided in the rear
housing 19. In addition, a first pressure regulation chamber 31a, a
suction chamber 33 and a discharge chamber 35 are formed in the
rear housing 19. The first pressure regulation chamber 31a is
disposed at the center of the rear housing 19. The discharge
chamber 35 is disposed annularly at an outer circumferential side
in the rear housing 19. Furthermore, the suction chamber 33 is
formed annularly between the first pressure regulation chamber 31a
and the discharge chamber 35 in the rear housing 19. The discharge
chamber 35 is connected to an outlet port which is not
illustrated.
[0068] Cylinder bores 21a, the number of which is the same as that
of the pistons 9, are formed in the cylinder block 21 at
equiangular intervals in a circumferential direction. Front end
sides of the respective cylinder bores 21a communicate with the
swash plate chamber 25. Furthermore, a retainer groove 21b that
restricts a lift amount of suction reed valves 41a, which will be
described later, is formed in the cylinder block 21.
[0069] Furthermore, a second shaft hole 21c that extends in the
front-rear direction of the compressor and communicates with the
swash plate chamber 25 is formed through the cylinder block 21. A
second sliding bearing 29b is provided in the second shaft hole
21c. Furthermore, a spring chamber 21d is formed in the cylinder
block 21. The spring chamber 21d is located between the swash plate
chamber 25 and the second shaft hole 21c. A return spring 37 is
disposed in the spring chamber 21d. The return spring 37 urges the
swash plate 5 frontward in the swash plate chamber 25 when the
inclination angle becomes minimum. Furthermore, a suction passage
39 that communicates with the swash plate chamber 25 is formed in
the cylinder block 21.
[0070] The valve unit 23 is provided between the rear housing 19
and the cylinder block 21. The valve unit 23 includes a valve plate
40, a suction valve plate 41, a discharge valve plate 43 and a
retainer plate 45.
[0071] Suction ports 40a, the number of which is the same as that
of the cylinder bores 21a, are formed in the valve plate 40, the
discharge valve plate 43 and the retainer plate 45. Furthermore,
discharge ports 40b, the number of which is the same as that of the
cylinder bores 21a, are formed in the valve plate 40 and the
suction valve plate 41. The respective cylinder bores 21a
communicate with the suction chamber 33 through the respective
suction ports 40a, and communicate with the discharge chamber 35
through the respective discharge ports 40b. Furthermore, a first
communication hole 40c and a second communication hole 40d are
formed in the valve plate 40, the suction valve plate 41, the
discharge valve plate 43 and the retainer plate 45. Through the
first communication hole 40c, the suction chamber 33 and the
suction passage 39 communicate with each other.
[0072] The suction valve plate 41 is provided on the front surface
of the valve plate 40. A plurality of suction reed valves 41a that
are capable of opening and closing the respective suction ports 40a
by elastic deformation are formed in the suction valve plate 41.
Furthermore, the discharge valve plate 43 is provided on the rear
surface of the valve plate 40. A plurality of discharge reed valves
43a that are capable of opening and closing the respective
discharge ports 40b by elastic deformation are formed in the
discharge valve plate 43. The retainer plate 45 is provided on the
rear surface of the discharge valve plate 43. The retainer plate 45
restricts a lift amount of the discharge reed valves 43a.
[0073] The drive shaft 3 is inserted from a boss 17c to the rear
side of the housing 1. The front end side of the drive shaft 3 is
supported by the shaft seal device 27 in the boss 17c and supported
by the first sliding bearing 29a in the first shaft hole 17d. The
rear end side of the drive shaft 3 is supported by the second
sliding bearing 29b in the second shaft hole 21c. In this manner,
the drive shaft 3 is rotatably supported around a driving axis O
with respect to the housing 1. A second pressure regulation chamber
31b is defined by the rear end of the drive shaft 3 in the second
shaft hole 21c. The second pressure regulation chamber 31b
communicates with the first pressure regulation chamber 31a through
the second communication hole 40d. A pressure regulation chamber 31
is formed by the first and the second pressure regulation chambers
31a and 31b.
[0074] As shown in FIG. 3, ring grooves 3c and 3d are formed at the
rear end of the drive shaft 3. O-rings 49a and 49b are provided in
the ring grooves 3c and 3d, respectively. The pressure regulation
chamber 31 is sealed with the O-rings 49a and 49b, whereby the
swash plate chamber 25 does not communicate with the pressure
regulation chamber 31. The O-rings 49a and 49b correspond to the
third seal member in the present invention.
[0075] As shown in FIG. 1, the link mechanism 7, the swash plate 5
and the actuator 13 are attached to the drive shaft 3. The link
mechanism 7 includes a lug plate 51, a pair of lug arms 53 that are
formed at the lug plate 51, and a pair of swash plate arms 5e and
5f. The lug plate 51 corresponds to the lug member in the present
invention. Furthermore, the swash plate arms 5e and 5f correspond
to the transmission member in the present invention.
[0076] The lug plate 51 is formed into a substantially annular
shape. The lug plate 51 is press-fitted to the drive shaft 3 and
rotatable integrally with the drive shaft 3. The lug plate 51 is
located at the front end side in the swash plate chamber 25 and
disposed in front of the swash plate 5. Furthermore, a thrust
bearing 55 is provided between the lug plate 51 and the front wall
17a.
[0077] As shown in FIG. 4, a fixed cylindrical portion 51a that is
formed into a cylindrical shape and extends in the front-rear
direction of the lug plate 51 is provided in a recessed manner in
the lug plate 51. As shown in FIG. 1, the fixed cylindrical portion
51a extends from the rear end surface of the lug plate 51 to a
position on an inner side of the thrust bearing 55 in the lug plate
51.
[0078] The lug arms 53 extend rearward from the lug plate 51.
Furthermore, a cam surface 51b is formed at the lug plate 51 at a
position between the lug arms 53. In FIG. 1 etc., only one of the
lug arms 53 is illustrated for ease of explanation.
[0079] As shown in FIG. 5, the swash plate 5 has a swash plate main
body 50, the swash plate arms 5e and 5f, and a protrusion 5g. The
protrusion 5g corresponds to the acted portion in the present
invention.
[0080] The swash plate main body 50 is formed into an annular
flat-plate shape and has a front surface 5a and a rear surface 5b;
in addition, a top-dead-center corresponding portion T for
positioning the respective pistons 9 at their top dead center is
defined therein. A restriction portion 5c that protrudes frontward
from the swash plate 5 is formed on the front surface 5a. As shown
in FIG. 1, the restriction portion 5c abuts on the lug plate 51
when the inclination angle of the swash plate 5 becomes maximum.
Furthermore, the swash plate main body 50 is formed with an
insertion hole 5d. The drive shaft 3 is inserted through the
insertion hole 5d.
[0081] As shown in FIG. 5, the swash plate arms 5e and 5f are
formed on the front surface 5a of the swash plate main body 50 at
positions eccentric toward the top-dead-center corresponding
portion T of the swash plate 5 from the driving axis O. The swash
plate arms 5e and 5f extend frontward from the front surface
5a.
[0082] The protrusion 5g protrudes frontward from the front surface
5a and is integrated with the swash plate main body 50. The
protrusion 5g is formed into a substantially hemispherical shape,
and located eccentrically toward the top-dead-center corresponding
portion T of the swash plate 5 from the driving axis O so as to be
disposed between the swash plate arm 5e and the swash plate arm
5f.
[0083] As shown in FIG. 1, by inserting the swash plate arms 5e and
5f between the lug arms 53, the lug plate 51 is connected to the
swash plate 5. Thereby, the swash plate 5 is rotatable along with
the lug plate 51 in the swash plate chamber 25. The tip ends of the
swash plate arms 5e and 5f abut on the cam surface 51b.
[0084] By connecting the lug plate 51 to the swash plate 5, the
swash plate arms 5e and 5f and the protrusion 5g are located
eccentrically toward the top-dead-center corresponding portion T of
the swash plate 5 from the driving axis O. In addition, the swash
plate arms 5e and 5f slide on the cam surface 51b, whereby the
swash plate 5 is able to change its inclination angle with respect
to the direction perpendicular to the driving axis O from the
maximum inclination angle shown in FIG. 1 to the minimum
inclination angle shown in FIG. 6 while substantially maintaining
the position of the top-dead-center corresponding portion T.
[0085] As shown in FIG. 4, the actuator 13 includes the lug plate
51, a movable body 13a and a control pressure chamber 13b.
[0086] The movable body 13a, through which the drive shaft 3 is
inserted, is slidable in contact with the drive shaft 3 to move in
the direction of the driving axis O. The movable body 13a is formed
into a cylindrical shape and coaxial with the drive shaft 3, and
the diameter thereof is smaller than that of the thrust bearing 55
shown in FIG. 1. As shown in FIG. 4, the movable body 13a has a
first movable cylindrical portion 131, a second movable cylindrical
portion 132 and a third movable cylindrical portion 133. The first
movable cylindrical portion 131 is located at a rear end side in
the movable body 13a and has the smallest diameter in the movable
body 13a. The second movable cylindrical portion 132 continues from
the front end of the first movable cylindrical portion 131 and is
formed such that its diameter increases gradually toward the front
side of the movable body 13a. The third movable cylindrical portion
133 continues from the front end of the second movable cylindrical
portion 132 and extends toward the front side of the movable body
13a. The third movable cylindrical portion 133 has the largest
diameter in the movable body 13a.
[0087] Furthermore, an acting portion 134 is integrally formed at
the rear end of the first movable cylindrical portion 131. As shown
in FIG. 1, the acting portion 134 extends vertically from a
position near the driving axis O toward the top-dead-center
corresponding portion T of the swash plate 5, and is located
eccentrically toward the top-dead-center corresponding portion T of
the swash plate 5 from the driving axis O. The acting portion 134
has an acting surface 134a which is formed into a flat shape. As
shown in FIG. 7, the acting surface 134a comes into point-contact
with the protrusion 5g at an operative position F. Thereby, the
movable body 13a is rotatable integrally with the lug plate 51 and
the swash plate 5. Here, since the protrusion 5g and the acting
portion 134 are located eccentrically toward the top-dead-center
corresponding portion T of the swash plate 5 from the driving axis
O, the operative position F is also located eccentrically toward
the top-dead-center corresponding portion T of the swash plate 5
from the driving axis O as shown in FIG. 1.
[0088] The movable body 13a is capable of being fitted to the lug
plate 51 by allowing the second movable cylindrical portion 132 and
the third movable cylindrical portion 133 shown in FIG. 4 to
advance into the fixed cylindrical portion 51a (see FIG. 1). When
the second movable cylindrical portion 132 and the third movable
cylindrical portion 133 has advanced farthest into the fixed
cylindrical portion 51a, the third movable cylindrical portion 133
reaches a position on an inner side of the thrust bearing 55 in the
fixed cylindrical portion 51a.
[0089] As shown in FIG. 4, the control pressure chamber 13b is
formed by the second movable cylindrical portion 132, the third
movable cylindrical portion 133, the fixed cylindrical portion 51a
and the drive shaft 3. Furthermore, a ring groove 131a is formed in
the inner circumferential surface of the first movable cylindrical
portion 131, and a ring groove 133a is formed in the outer
circumferential surface of the third movable cylindrical portion
133. O-rings 49c and 49d are provided in the ring grooves 131a and
133a, respectively. The O-ring 49c corresponds to the first seal
member in the present invention, and the O-ring 49d corresponds to
the second seal member in the present invention. The control
pressure chamber 13b is sealed with the O-rings 49c and 49d,
whereby the hermeticity of the control pressure chamber 13b is
ensured.
[0090] As shown in FIG. 1, an axial path 3a that extends in the
direction of the driving axis O from the rear end of the drive
shaft 3 toward the front end thereof and a radial path 3b that
extends radially from the front end of the axial path 3a and opens
at the outer circumferential surface of the drive shaft 3 are
formed in the drive shaft 3. The rear end of the axial path 3a
opens to the pressure regulation chamber 31. The radial path 3b
opens to the control pressure chamber 13b. Through the axial path
3a and the radial path 3b, the pressure regulation chamber 31 and
the control pressure chamber 13b communicate with each other.
[0091] The drive shaft 3 is connected to a pulley or an
electromagnetic clutch, which are not illustrated, via a screw
portion 3e which is formed at the tip end thereof.
[0092] The pistons 9 are respectively accommodated in the
respective cylinder bores 21a and capable of reciprocating in the
respective cylinder bores 21a. Compression chambers 57 are defined
in the respective cylinder bores 21a by the respective pistons 9
and the valve unit 23.
[0093] Furthermore, an engaging portion 9a is formed in a recessed
manner in each of the pistons 9. The shoes 11a and 11b formed into
a hemispherical shape are provided in the respective engaging
portions 9a. The shoes 11a and 11b convert the rotation of the
swash plate 5 into reciprocal movement of the pistons 9. The shoes
11a and 11b correspond to the conversion mechanism in the present
invention. In this manner, the pistons 9 are able to reciprocate in
the cylinder bores 21a at a stroke corresponding to the inclination
angle of the swash plate 5. Alternatively, instead of the shoes 11a
and 11b, it is also possible to employ a wobble type conversion
mechanism, in which a wobble plate is supported at the side of the
rear surface 5b of the swash plate main body 50 via a thrust
bearing and the wobble plate is connected to the respective pistons
9 via connecting rods.
[0094] As shown in FIG. 2, the control mechanism 15 has a low
pressure passage 15a, a high pressure passage 15b, a control valve
15c, an orifice 15d, the axial path 3a and the radial path 3b. A
control passage in the present invention is formed by the low
pressure passage 15a, the high pressure passage 15b, the axial path
3a and the radial path 3b. Furthermore, the axial path 3a and the
radial path 3b serve as variable pressure passages.
[0095] The low pressure passage 15a is connected to the pressure
regulation chamber 31 and the suction chamber 33. Thereby, the
control pressure chamber 13b, the pressure regulation chamber 31
and the suction chamber 33 communicate with one another through the
low pressure passage 15a, the axial path 3a and the radial path 3b.
The high pressure passage 15b is connected to the pressure
regulation chamber 31 and the discharge chamber 35. The control
pressure chamber 13b, the pressure regulation chamber 31 and the
discharge chamber 35 communicate with one another through the high
pressure passage 15b, the axial path 3a and the radial path 3b.
Furthermore, the high pressure passage 15b is provided with the
orifice 15d, whereby the flow rate of the refrigerant flowing
through the high pressure passage 15b is reduced.
[0096] The control valve 15c is provided at the low pressure
passage 15a. The control valve 15c is capable of regulating the
flow rate of the refrigerant flowing through the low pressure
passage 15a based on the pressure in the suction chamber 33.
[0097] In this compressor, a pipe that leads to the evaporator is
connected to the inlet port 250 shown in FIG. 1, and a pipe that
leads to a condenser is connected to the outlet port. The condenser
is connected to the evaporator via pipes and an expansion valve.
The refrigeration circuit of vehicle air-conditioning apparatus is
constituted by the compressor, the evaporator, the expansion valve,
the condenser and the like. Illustration of the evaporator, the
expansion valve, the condenser and the pipes is omitted.
[0098] In the compressor configured as above, by rotation of the
drive shaft 3, the swash plate 5 rotates and the pistons 9
reciprocate in the respective cylinder bores 21a. The volume of the
compression chambers 57 thus changes in response to the stroke of
the pistons 9. The refrigerant introduced from the evaporator into
the swash plate chamber 25 through the inlet port 250 thus passes
the suction chamber 33 through the suction passage 39 and then is
compressed in the compression chambers 57. Subsequently, the
refrigerant compressed in the compression chambers 57 is discharged
to the discharge chamber 35 and then discharged to the condenser
from the outlet port.
[0099] During this time, in this compressor, a piston compression
force that reduces the inclination angle of the swash plate 5 acts
on the swash plate 5, the lug plate 51 and the like. By changing
the inclination angle of the swash plate 5 to increase or decrease
the stroke of the pistons 9, it is possible to perform capacity
control in this compressor.
[0100] Specifically, in the control mechanism 15, when the control
valve 15c shown in FIG. 2 increases the flow rate of the
refrigerant flowing through the low pressure passage 15a, the
refrigerant in the discharge chamber 35 is less likely to pass the
high pressure passage 15b and the orifice 15d and be stored in the
pressure regulation chamber 31. Therefore, the pressure in the
control pressure chamber 13b becomes substantially equal to that in
the suction chamber 33. As a result, as shown in FIG. 1, due to the
piston compression force acting on the swash plate 5, in the
actuator 13, the volume of the control pressure chamber 13b
decreases and the movable body 13a moves from the side of the swash
plate 5 toward the lug plate 51 in the direction of the driving
axis O. Then, in the movable body 13a, the second movable
cylindrical portion 132 and the third movable cylindrical portion
133 advance into the fixed cylindrical portion 51a.
[0101] At the same time, in this compressor, due to the piston
compression force and the urging force of the return spring 37
acting on the swash plate 5, the swash plate arms 5e and 5f slide
on the cam surface 51b so as to move away from the driving axis O.
Therefore, a bottom dead center side of the swash plate 5 pivots in
a clockwise direction while substantially maintaining the position
of the top-dead-center corresponding portion T. In this manner, in
this compressor, the inclination angle of the swash plate 5 with
respect to the direction perpendicular to the driving axis O of the
drive shaft 3 increases. Thereby, in this compressor, the stroke of
the pistons 9 increases and the discharge capacity per rotation of
the drive shaft 3 becomes large. Here, the inclination angle of the
swash plate 5 shown in FIG. 1 is the maximum inclination angle in
this compressor. When the swash plate 5 is at the maximum
inclination angle, the swash plate arms 5e and 5f abut on the cam
surface 51b at a first position P1.
[0102] On the other hand, when the control valve 15c shown in FIG.
2 decreases the flow rate of the refrigerant flowing through the
low pressure passage 15a, the refrigerant in the discharge chamber
35 is more likely to pass the high pressure passage 15b and the
orifice 15d and be stored in the pressure regulation chamber 31.
Therefore, the pressure in the control pressure chamber 13b becomes
substantially equal to that of the discharge chamber 35, and the
pressure in the control pressure chamber 13b becomes higher than
that of the swash plate chamber 25. As a result, as shown in FIG.
6, in the actuator 13, the volume of the control pressure chamber
13b increases and the movable body 13a moves away from the lug
plate 51 toward the swash plate 5 in the direction of the driving
axis O.
[0103] Thereby, in this compressor, the acting surface 134a of the
acting portion 134 operates in such a manner as to press the
protrusion 5g rearward in the swash plate chamber 25 at the
operative position F. Therefore, the swash plate arms 5e and 5f
slide on the cam surface 51b so as to approach the driving axis O,
and the bottom dead center side of the swash plate 5 pivots in a
counterclockwise direction while substantially maintaining the
position of the top-dead-center corresponding portion T. In this
manner, in this compressor, the inclination angle of the swash
plate 5 with respect to the direction perpendicular to the driving
axis O of the drive shaft 3 decreases. Thereby, in this compressor,
the stroke of the pistons 9 decreases and the discharge capacity
per rotation of the drive shaft 3 becomes small. Furthermore, when
the inclination angle decreases, the swash plate 5 abuts on the
return spring 37. Here, the inclination angle of the swash plate 5
shown in FIG. 6 is the minimum inclination angle in this
compressor. When the swash plate 5 is at the minimum inclination
angle, the swash plate arms 5e and 5f abut on the cam surface 51b
at a second position P2.
[0104] As described above, this compressor employs the actuator 13
so as to change the inclination angle of the swash plate 5 by
changing the pressure in the control pressure chamber 13b, which
has a smaller volume than the swash plate chamber 25. Therefore, in
this compressor, the amount of the refrigerant required to change
the inclination angle can be reduced as compared to the compressor
configured to change the inclination angle by changing the pressure
in the swash plate chamber 25. As a result, this compressor is
capable of suppressing enlargement of the swash plate chamber 25
and the housing 1.
[0105] Furthermore, in this compressor, the swash plate arms 5e and
5f of the link mechanism 7 transmit the rotation of the lug plate
51 to the swash plate 5 and permit change of the inclination angle
while substantially maintaining the position of the top-dead-center
corresponding portion T of the swash plate 5. Furthermore, the
acting portion 134 of the movable body 13a and the protrusion 5g of
the swash plate 5 are located eccentrically toward the
top-dead-center corresponding portion T of the swash plate 5 from
the driving axis O. The acting surface 134a of the acting portion
134 comes into point-contact with the protrusion 5g at the
operative position F, and in order to decrease the inclination
angle of the swash plate 5, the acting surface 134a presses the
protrusion 5g. The operative position F moves in accordance with
the change of the inclination angle.
[0106] Specifically, in this compressor, as shown in FIG. 7A, when
the inclination angle is maximum, the operative position F is
located at a position near the top-dead-center corresponding
portion T of the swash plate 5. Then, as the inclination angle
decreases, the position where the swash plate arms 5e and 5f abuts
on the cam surface 51b moves toward the second position P2.
Thereby, in this compressor, as shown by the white arrow in FIG.
7B, the operative position F moves toward the driving axis O as the
inclination angle of the swash plate 5 decreases. In other words,
the operative position F when the inclination angle is maximum is
closer to the top-dead-center corresponding portion T of the swash
plate 5 as compared to the operative position F when the
inclination angle is minimum. Here, in this compressor, even when
the inclination angle becomes minimum, the operative position F
does not move to the opposite side of the top-dead-center
corresponding portion T across the driving axis O.
[0107] Therefore, in this compressor, as compared with the case
where the operative position F has a constant distance from the
driving axis O, it is possible to move the movable body 13a without
increasing the variable differential pressure at the time of
decreasing the inclination angle so as to provide a large thrust
force. That is, in this compressor, the load exerted on the movable
body 13a at the time of decreasing the inclination angle can be
reduced. Consequently, in this compressor, the amount of change in
the variable differential pressure when the inclination angle
changes is small; therefore, it is easy to change the inclination
angle quickly in response to the driving conditions of the vehicle
on which the compressor is mounted, and high controllability can be
exhibited.
[0108] Furthermore, in this compressor, since the operative
position F moves as described above in accordance with the change
of the inclination angle of the swash plate 5, the stroke of the
movable body 13a in the direction of the driving axis O is reduced
as compared to the compressor in which the operative position F has
a constant distance from the driving axis O, provided that the
range of their inclination angle is the same. Therefore,
enlargement of the compressor in the axial length is suppressed.
These operations will be specifically described below by comparison
with a comparative example.
[0109] The compressor of the comparative example is configured by
partially changing the compressor of Embodiment 1 such that the
protrusion 5g and the acting portion 134 are not provided in the
swash plate 5 and the movable body 13a. Thereby, in the compressor
of the comparative example, the rear end of the first movable
cylindrical portion 131 of the movable body 13a abuts on the front
surface 5a at a position around the insertion hole 5d. Therefore,
in the compressor of the comparative example, the movable body 13a
abuts on the swash plate 5 at a position almost on the driving axis
O. As a result, in this compressor, when the inclination angle of
the swash plate 5 changes, the operative position between the
movable body 13a and the swash plate 5 moves in parallel with the
direction of the driving axis O. That is, in the compressor of the
comparative example, the distance between the operative position
and the driving axis O is constant and unchanged even when the
inclination angle changes.
[0110] Therefore, as the graph in FIG. 8 shows, in the compressor
of the comparative example, it is necessary to increase the
variable differential pressure when the inclination angle decreases
so as to move the movable body 13a by a larger thrust force. In
contrast, in the compressor of Embodiment 1, it is possible to move
the movable body 13a without increasing the variable differential
pressure to thereby provide a large thrust force as described
above. Consequently, in the compressor of Embodiment 1, the
variable differential pressure required at the time of changing the
inclination angle can be made small and almost uniform as a
whole.
[0111] Furthermore, as shown in FIG. 9, in the compressor of the
comparative example, in order to displace the swash plate 5 at the
maximum inclination angle in this drawing (see the double-dashed
chain line) until it reaches the minimum inclination angle, the
movable body 13a needs to move by a distance S2 in the direction of
the driving axis O.
[0112] In contrast, in the compressor of Embodiment 1, it is
sufficient if the movable body 13a moves by a distance S1 in the
direction of the driving axis O in order to displace the swash
plate 5 at the maximum inclination angle until it reaches the
minimum inclination angle. That is, in the compressor of Embodiment
1, the stroke of the movable body 13a in the direction of the
driving axis O is shorter than that of the compressor in the
comparative example.
[0113] Accordingly, the compressor of Embodiment 1 is capable of
exhibiting high controllability and excellent mountability.
[0114] In particular, in this compressor, since the movable body
13a directly abuts on and presses the swash plate 5 via the acting
portion 134 and the protrusion 5g, the direction of the load which
acts on the swash plate 5 is less likely to vary. Consequently, in
this compressor, the movable body 13a easily presses the swash
plate 5 in the direction of the driving axis O, and the movable
body 13a is able to stably change the inclination angle of the
swash plate 5. Furthermore, in this compressor, because the posture
of the movable body 13a is stable, leakage of the pressure from the
control pressure chamber 13b is less likely to occur.
[0115] Furthermore, in this compressor, in order to change the
inclination angle of the swash plate 5, the movable body 13a merely
abuts directly on and presses the swash plate 5, and the acting
portion 134 is not connected to the protrusion 5g with a connection
pin or the like. Consequently, in this compressor, there is no risk
that the configuration of a connecting portion changes the posture
of the movable body 13a, and thus, the posture of the movable body
13a is less likely to change at the time of changing the
inclination angle. Furthermore, in this compressor, it is possible
to suppress complication of the configuration and realize reduction
in manufacturing cost.
[0116] Furthermore, in this compressor, the drive shaft 3 is
inserted through the movable body 13a, and the movable body 13a is
capable of being fitted to the lug plate 51 by accommodating the
movable body 13a in the fixed cylindrical portion 51a. Here, in
this compressor, the third movable cylindrical portion 133 of the
movable body 13a advances to the position on the inner side of the
thrust bearing 55 in the fixed cylindrical portion 51a. Therefore,
in this compressor, the space for allowing the movable body 13a to
move in the direction of the driving axis O can be suitably
provided between the lug plate 51 and the swash plate 5 while
making the axial length short. Furthermore, the thrust bearing 55
provided in the compressor can suitably receive the suction
reaction force and the compression reaction force which act on the
pistons 9.
[0117] Furthermore, in this compressor, the control pressure
chamber 13b can be suitably formed between the lug plate 51 and the
movable body 13a by the fixed cylindrical portion 51a. In this
compressor, the hermeticity of the control pressure chamber 13b is
suitably ensured by the O-rings 49c and 49d which are provided at
the first and the third movable cylindrical portions 131 and 133
respectively.
[0118] Furthermore, in this compressor, the acting portion 134 and
the protrusion 5g are located eccentrically toward the
top-dead-center corresponding portion T from the driving axis O,
and the operative position F moves toward the driving axis O as
described above as the inclination angle of the swash plate 5
decreases. Therefore, in this compressor, the space for allowing
the movable body 13a to move in the direction of the driving axis O
is easily provided between the lug plate 51 and the swash plate
without disrupting the change of the inclination angle. Therefore,
in this compressor, it is possible to increase the diameter of the
actuator 13 to quickly move the movable body 13a by a sufficient
thrust force. Also in this aspect, this compressor is capable of
quickly changing the inclination angle in response to the driving
conditions of a vehicle.
[0119] Furthermore, in this compressor, the acting portion 134
protrudes from the first movable cylindrical portion 131 toward the
top-dead-center corresponding portion T of the swash plate 5 and is
integrated with the movable body 13a. Furthermore, the acting
surface 134a is formed at the acting portion 134. Thereby, in this
compressor, the acting surface 134a can easily abut on the
protrusion 5g at the position eccentric toward the top-dead-center
corresponding portion T from the driving axis O. Here, since the
protrusion 5g is formed to protrude in a substantially
hemispherical manner, the acting surface 134a can be suitably
brought into point-contact with the protrusion 5g. Consequently, in
this compressor, the contact area between the acting surface 134a
and the protrusion 5g can be made small, whereby the swash plate 5
can easily change its inclination angle.
[0120] Furthermore, the protrusion 5g is integrally formed with the
front surface 5a of the swash plate main body 50. Therefore, in
this compressor, it is possible to reduce the number of components,
facilitate manufacturing, and reduce manufacturing cost.
[0121] Furthermore, in this compressor, the swash plate chamber 25
and the suction chamber 33 communicate with each other through the
suction passage 39. Thereby, in this compressor, the pressure in
the swash plate chamber 25 can be made low as well as the suction
chamber 33.
[0122] Furthermore, the control mechanism 15 adjusts the pressure
in the pressure regulation chamber 31 and thus the pressure in the
control pressure chamber 13b by regulating the opening degree of
the control valve 15c. In addition, the axial path 3a and the
radial path 3b are formed in the drive shaft 3. Consequently, in
this compressor, it is possible to suitably change the pressure in
the control pressure chamber 13b and suitably move the movable body
13a while downsizing the control mechanism 15.
[0123] Furthermore, in this compressor, the hermeticity of the
pressure regulation chamber 31 is suitably ensured by the O-rings
49a and 49b which are provided at the rear end of the drive shaft
3.
Embodiment 2
[0124] As shown in FIG. 10, in a compressor of Embodiment 2, the
swash plate 5 has the swash plate main body 50, the swash plate
arms 5e and 5f and a contact member 59. The contact member 59 also
corresponds to the acted portion in the present invention.
[0125] The contact member 59 is formed to be a separate body from
the swash plate main body 50. The contact member 59 is attached to
the front surface 5a of the swash plate main body 50 at a position
between the swash plate arms 5e and 5f, and located eccentrically
toward the top-dead-center corresponding portion T of the swash
plate 5 from the driving axis O.
[0126] A protrusion 59a that protrudes frontward is formed at the
contact member 59. The protrusion 59a is formed into a
substantially hemispherical shape. The protrusion 59a comes into
point-contact with the acting surface 134a of the acting portion
134 at the operative position F. In this manner, in this
compressor, via the acting surface 134a and the protrusion 59a, the
acting portion 134 abuts on the contact member 59 at a position
eccentric toward the top-dead-center corresponding portion T of the
swash plate 5 from the driving axis O. The other components of this
compressor are the same as those of the compressor of Embodiment 1,
and, where the components are the same, same reference numerals are
used and detailed explanation thereof is omitted.
[0127] In this compressor, since the swash plate 5 and the contact
member 59 are separate bodies, it is possible to improve the
flexibility of design with respect to the swash plate main body 50
and the contact member 59. The other operations of this compressor
are the same as those of the compressor of Embodiment 1.
[0128] Although the present invention has been described above in
line with Embodiments 1 and 2, it is needless to say that the
present invention is not limited to Embodiments 1 and 2 described
above and may be modified and applied as appropriate without
departing from the gist of the invention.
[0129] For example, the compressors of Embodiments 1 and 2 may be
configured such that the operative position F moves toward the
driving axis O while the inclination angle of the swash plate 5
decreases to a predetermined angle from the maximum state, and the
operative position F does not move while the inclination angle of
the swash plate 5 reaches its minimum inclination angle from the
predetermined angle.
[0130] Furthermore, the protrusion 5g and the protrusion 59a may be
formed into a flat-plate shape, and the acting surface 134a of the
acting portion 134 may be formed into a curved shape. This enables
the protrusion 5g and the protrusion 59a to come into line-contact
with the acting portion 134 at the operative position F.
[0131] Furthermore, the control mechanism 15 may be configured such
that the control valve 15c is provided at the high pressure passage
15b and the orifice 15d is provided at the low pressure passage
15a. In this case, the flow rate of the high-pressure refrigerant
flowing through the high pressure passage 15b can be regulated by
the control valve 15c. Therefore, due to the high pressure in the
discharge chamber 35, the pressure in the control pressure chamber
13b can be increased quickly and the compression capacity can be
decreased quickly. Furthermore, instead of the control valve 15c, a
three-way valve that is connected to the low pressure passage 15a
and the high pressure passage 15b may be provided so that the flow
rate of the refrigerant flowing through the low pressure passage
15a and the high pressure passage 15b is adjusted by regulating an
opening degree of the three-way valve.
INDUSTRIAL APPLICABILITY
[0132] The present invention is applicable to air-conditioning
apparatus and the like.
REFERENCE SIGNS LIST
[0133] 1 HOUSING [0134] 3 DRIVE SHAFT [0135] 3a AXIAL PATH (CONTROL
PASSAGE) [0136] 3b RADIAL PATH (CONTROL PASSAGE) [0137] 5 SWASH
PLATE [0138] 5d INSERTION HOLE [0139] 5e, 5f SWASH PLATE ARM
(TRANSMISSION MEMBER) [0140] 5g PROTRUSION (ACTED PORTION) [0141] 7
LINK MECHANISM [0142] 9 PISTON [0143] 11a, 11b SHOE (CONVERSION
MECHANISM) [0144] 13 ACTUATOR [0145] 13a MOVABLE BODY [0146] 13b
CONTROL PRESSURE CHAMBER (CONTROL PASSAGE) [0147] 15 CONTROL
MECHANISM [0148] 15a LOW PRESSURE PASSAGE (CONTROL PASSAGE) [0149]
15b HIGH PRESSURE PASSAGE (CONTROL PASSAGE) [0150] 15c CONTROL
VALVE [0151] 25 SWASH PLATE CHAMBER [0152] 31 PRESSURE REGULATION
CHAMBER [0153] 33 SUCTION CHAMBER [0154] 35 DISCHARGE CHAMBER
[0155] 21a CYLINDER BORE [0156] 49a, 49b O-RING (THIRD SEAL MEMBER)
[0157] 49c O-RING (FIRST SEAL MEMBER) [0158] 49d O-RING (SECOND
SEAL MEMBER) [0159] 51 LUG PLATE (LUG MEMBER) [0160] 51a FIXED
CYLINDRICAL PORTION [0161] 55 THRUST BEARING [0162] 59 CONTACT
MEMBER (ACTED PORTION) [0163] 59a PROTRUSION [0164] 131 FIRST
MOVABLE CYLINDRICAL PORTION (MOVABLE CYLINDRICAL PORTION) [0165]
132 SECOND MOVABLE CYLINDRICAL PORTION (MOVABLE CYLINDRICAL
PORTION) [0166] 133 THIRD MOVABLE CYLINDRICAL PORTION (MOVABLE
CYLINDRICAL PORTION) [0167] 134 ACTING PORTION [0168] F OPERATIVE
POSITION [0169] O DRIVING AXIS [0170] T TOP-DEAD-CENTER
CORRESPONDING PORTION
* * * * *