U.S. patent application number 15/803160 was filed with the patent office on 2018-05-10 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 Suguru HIROTA, Shinichi KAKEGAWA, Hiroshi KUBO, Noriaki SATAKE, Tomoji TARUTANI, Kenji YAMAMOTO.
Application Number | 20180128252 15/803160 |
Document ID | / |
Family ID | 62003138 |
Filed Date | 2018-05-10 |
United States Patent
Application |
20180128252 |
Kind Code |
A1 |
YAMAMOTO; Kenji ; et
al. |
May 10, 2018 |
VARIABLE DISPLACEMENT TYPE SWASH PLATE COMPRESSOR
Abstract
A variable displacement swash plate type compressor includes a
crank chamber, a suction chamber, a drive shaft, a swash plate, and
a bleeding passage connecting the crank chamber and the suction
chamber. The bleeding passage has an axial passage and first and
second radial passages in the drive shaft. The second radial
passage opens on an outer peripheral surface of the drive shaft at
a position that is closer to the swash plate than the first radial
passage. The first radial passage is in constant communication with
the crank chamber. The drive shaft has a valve member that is
movable in the axial direction with the swash plate. The second
radial passage is connected to the crank chamber when the swash
plate is at maximum or minimum inclination angles and disconnected
from the crank chamber by the valve member when the swash plate is
at an intermediate inclination angle.
Inventors: |
YAMAMOTO; Kenji; (Aichi-ken,
JP) ; SATAKE; Noriaki; (Aichi-ken, JP) ;
KAKEGAWA; Shinichi; (Aichi-ken, JP) ; KUBO;
Hiroshi; (Aichi-ken, JP) ; HIROTA; Suguru;
(Aichi-ken, JP) ; TARUTANI; Tomoji; (Aichi-ken,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOYOTA JIDOSHOKKI |
Aichi |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Aichi
JP
|
Family ID: |
62003138 |
Appl. No.: |
15/803160 |
Filed: |
November 3, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 2027/1886 20130101;
F04B 2027/1822 20130101; F04B 27/1804 20130101; F04B 27/10
20130101; F04B 2027/1845 20130101 |
International
Class: |
F04B 27/18 20060101
F04B027/18 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2016 |
JP |
2016-217239 |
Claims
1. A variable displacement swash plate type compressor comprising:
a housing having a discharge chamber, a suction chamber, a crank
chamber, and a cylinder bore; a drive shaft rotatably supported in
the crank chamber; a swash plate disposed in the crank chamber and
supported on the drive shaft for rotation with the drive shaft; a
piston reciprocally movable in the cylinder bore with a stroke
length depending on an inclination angle of the swash plate, the
piston forming a compression chamber in the cylinder bore; and a
control mechanism configured to change the inclination angle of the
swash plate between a maximum inclination angle and a minimum
inclination angle by a pressure within the crank chamber, the
control mechanism having a feeding passage connecting the discharge
chamber and the crank chamber, a bleeding passage connecting the
crank chamber and the suction chamber, and a displacement control
valve configured to adjust at least one of an opening degree of the
feeding passage and the bleeding passage, wherein the bleeding
passage includes: an axial passage formed in the drive shaft and
extending in an axial direction of the drive shaft; a first radial
passage formed in the drive shaft, communicating with the axial
passage, and extending in a radial direction of the drive shaft to
open on an outer peripheral surface of the drive shaft in the crank
chamber; and at least one second radial passage formed in the drive
shaft, communicating with the axial passage, and extending in the
radial direction of the drive shaft to open on the outer peripheral
surface of the drive shaft at a position that is closer to the
swash plate than the first radial passage is to the swash plate,
and a valve member is disposed on the drive shaft, the valve member
is movable in the axial direction of the drive shaft with the swash
plate, the first radial passage is in constant communication with
the crank chamber, and the valve member is configured to connect
the second radial passage to the crank chamber when the swash plate
is at the maximum inclination angle or the minimum inclination
angle, .sub.and to disconnect the second radial passage from the
crank chamber when the swash plate is at an intermediate
inclination angle that is smaller than the maximum inclination
angle and greater than the minimum inclination angle.
2. The variable displacement swash plate type compressor according
to claim 1, wherein the first radial passage opens on the outer
peripheral surface of the drive shaft in the crank chamber at a
position that is closer to the cylinder bore than the second radial
passage is to the cylinder bore.
3. The variable displacement swash plate type compressor according
to claim 1, wherein the housing includes a cylinder block having
the cylinder bore and a first housing member cooperating with the
cylinder block to define the crank chamber, the first housing
member has a sealing member holding the drive shaft to be rotatable
and sealing off the crank chamber from the outside of the first
housing member, the crank chamber accommodates a lug member
disposed on the drive shaft and facing the swash plate, the
bleeding passage has a third radial passage formed in the drive
shaft, communicating with the axial passage and extending in the
radial direction of the drive shaft to open on the outer peripheral
surface of the drive shaft between the sealing member and the lug
member, and the third radial passage is in constant communication
with the crank chamber.
4. The variable displacement swash plate type compressor according
to claim 1, wherein the second radial passage includes a plurality
of second radial passages, and the second radial passages open on
the outer peripheral surface of the drive shaft at intervals in a
circumferential direction of the drive shaft.
5. The variable displacement swash plate type compressor according
to claim 1, wherein the crank chamber accommodates a lug member
disposed on the drive shaft and facing the swash plate, the swash
plate includes a swash plate arm that is configured to transmit a
rotary movement of the drive shaft from the lug member to the swash
plate, the swash plate has an insertion hole for receiving the
drive shaft and an abutment portion abutting on the outer
peripheral surface of the drive shaft in the insertion hole,
wherein the abutment portion is disposed opposite to the swash
plate arm across an axis of the drive shaft, and the second radial
passage opens on the outer peripheral surface of the drive shaft at
a position that is located away from the abutment portion in a
circumferential direction of the drive shaft.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a variable displacement
swash plate type compressor.
[0002] Japanese Unexamined Patent Application Publication No.
2006-132446 discloses a variable displacement swash plate type
compressor (hereinafter simply referred to as compressor). The
compressor includes a housing, a drive shaft, a swash plate, a
piston, and a control mechanism. The housing includes a cylinder
block having therethrough a cylinder bore, a first housing member
cooperating with the cylinder block to define a crank chamber
between the first housing member and the cylinder block, and a
second housing member having therein a discharge chamber and a
suction chamber. The drive shaft is rotatably supported in the
housing, and has thereon a lug member which is disposed in the
crank chamber.
[0003] The swash plate is rotatably supported on the drive shaft
for rotation with the drive shaft and faces the lug member in the
crank chamber. The piston is reciprocally movable in the cylinder
bore with a stroke length depending on the inclination angle of the
swash plate, thereby forming a compression chamber in the cylinder
bore. The compressor further has a shaft hole, a sealing member,
and a communication passage formed in the first housing member. The
shaft hole for receiving the drive shaft is connected to the crank
chamber. The sealing member is disposed outward of the crank
chamber and the shaft hole in the compressor in the axial direction
of the drive shaft. The sealing member supports the drive shaft to
be rotatable and creates a tight seal between crank chamber and
outside of the housing. The communication passage extends so as to
intersect with the drive shaft. The communication passage opens to
the crank chamber at one end thereof and opens at another end
thereof between the shaft hole and the sealing member.
[0004] The control mechanism has a feeding passage connecting the
discharge chamber and the crank chamber, a bleeding passage
connecting the crank chamber and the suction chamber, and a
displacement control valve. The control mechanism is configured to
control the inclination angle of the swash plate with the pressure
in the crank chamber. The displacement control valve is configured
to adjust the opening degree of the feeding passage. The bleeding
passage includes an axial passage, first radial passages, and
second radial passages. The axial passage extends in the drive
shaft in the axial direction of the drive shaft. The first and the
second radial passages communicate with the axial passage in the
drive shaft and extend from the axial passage in the radial
direction of the drive shaft to open on an outer peripheral surface
of the drive shaft. Specifically, the first radial passages are
located outward of the crank chamber and open on the outer
peripheral surface of the drive shaft between the lug member and
the sealing member. The first radial passages are in constant
communication with the crank chamber through the communication
passage. The second radial passages open on the outer peripheral
surface of the drive shaft at positions near the swash plate, where
a refrigerant gas contains smaller amount of lubricant compared to
the refrigerant gas exists in other locations in the crank chamber.
The compressor further includes a valve member that is axially
movable on the drive shaft along with the swash plate.
[0005] In this compressor, the inclination angle of the swash plate
decreases as the pressure within the crank chamber is increased by
the control mechanism, with the result that the discharge volume
per rotation of the drive shaft decreases.
[0006] While on the other hand, the inclination angle of the swash
plate increases as the pressure within the crank chamber is
decreased by the control mechanism, with the result that the
discharge volume per rotation of the drive shaft increases. When
the inclination angle of the swash plate is the maximum or the
minimum inclination angles, the valve member axially moves on the
drive shaft to close the openings of the second radial passages on
the drive shaft, therefore, the second radial passages are
disconnected from the crank chamber by the valve member, which
prevents the refrigerant gas in the crank chamber from being
introduced from the second radial passages into the suction chamber
through the axial passage. While the inclination angle of the swash
plate is an intermediate inclination angle, which is smaller than
the maximum inclination angle and greater than the minimum
inclination angle, the valve member allows the second radial
passages to connect to the crank chamber. As a result, the
refrigerant gas in the crank chamber is introduced from each of the
first and the second radial passages into the suction chamber
through the axial passage. Since the refrigerant gas existing near
the swash plate contains small amount of lubricant as described
above, the refrigerant gas introduced from the crank chamber into
the suction chamber through the second radial passages and the
axial passage contains smaller amount of lubricant than the
refrigerant gas introduced from the crank chamber into the suction
chamber through the first radial passages and the axial passage. In
this compressor, the second radial passages are connected to the
crank chamber. This configuration enables the reduction of the flow
rate of the refrigerant gas introduced from the crank chamber into
the suction chamber through the first radial passages and the axial
passage, while lubricant does not flow excessively from the crank
chamber into the suction chamber.
[0007] In the adjustment of the pressure within the crank chamber,
this configuration of the compressor enables to secure the flow
rate of the refrigerant gas introduced from the crank chamber into
the suction chamber through the first and the second radial
passages and the axial passage, while controlling the amount of the
lubricant introduced with the refrigerant gas from the crank
chamber to the suction chamber. Accordingly, this compressor is
capable of securing the lubricant in the crank chamber to lubricate
inside the crank chamber while exhibiting high pressure
controllability, which leads to high durability of the
compressor.
[0008] However, a compressor having higher durability while having
higher controllability is requested. In this compressor, the crank
chamber and the second radial passages do not communicate with each
other when the inclination angle of the swash plate is the minimum
inclination angle, so that flow rate of the refrigerant gas with
the lubricant introduced from the crank chamber into the suction
chamber through the first radial passages and the axial passage
increases. There is a case in that the refrigerant gas with the
lubricant introduced from the crank chamber into the suction
chamber is introduced into the compression chamber, and then
discharged through the discharge chamber to a condenser outside the
compressor, even at the minimum inclination angle of the swash
plate and minimum discharge volume. Also, at the minimum
inclination angle of the swash plate, the lubricant introduced with
the refrigerant gas into the crank chamber decreases because the
flow rate of the refrigerant gas introduced from an evaporator
outside the compressor into the suction chamber decreases.
Therefore, this compressor may cause the shortage of the lubricant
in the crank chamber and is difficult to further improve its
durability.
[0009] The present invention, which has been made in light of the
above described problems, is directed to providing a variable
displacement swash plate type compressor that has higher durability
and controllability.
SUMMARY OF THE INVENTION
[0010] In accordance with one aspect of the present invention,
there is provided a variable displacement swash plate type
compressor including a housing, a drive shaft, a swash plate, a
piston, and a control mechanism. The housing has a discharge
chamber, a suction chamber, a crank chamber, and a cylinder bore.
The drive shaft is rotatably supported in the crank chamber. The
swash plate is disposed in the crank chamber and supported on the
drive shaft for rotation with the drive shaft. The piston is
reciprocally movable in the cylinder bore with a stroke length
depending on an inclination angle of the swash plate. The piston
forms a compression chamber in the cylinder bore. The control
mechanism is configured to change the inclination angle of the
swash plate between a maximum inclination angle and a minimum
inclination angle by a pressure within the crank chamber. The
control mechanism has a feeding passage connecting the discharge
chamber and the crank chamber, a bleeding passage connecting the
crank chamber and the suction chamber, and a displacement control
valve. The displacement control valve is configured to adjust at
least one of an opening degree of the feeding passage and the
bleeding passage. The bleeding passage has an axial passage, a
first radial passages, and at least one second radial passage. The
axial passage is formed in the drive shaft in an axial direction of
the drive shaft. The first radial passage is formed in the drive
shaft, communicates with the axial passage and extends in a radial
direction of the drive shaft to open on an outer peripheral surface
of the drive shaft in the crank chamber. The second radial passage
is formed in the drive shaft, communicates with the axial passage
and extends in the radial direction of the drive shaft to open on
the outer peripheral surface of the drive shaft at a position that
is closer to the swash plate than the first radial passage is to
the swash plate. A valve member is disposed on the drive shaft. The
valve member is movable in the axial direction of the drive shaft
with the swash plate. The first radial passage is in constant
communication with the crank chamber. The valve member is
configured to connect the second radial passage to the crank
chamber when the swash plate is at the maximum inclination angle or
the minimum inclination angle and to disconnect the second radial
passage from the crank chamber when the swash plate is at an
intermediate inclination angle that is smaller than the maximum
inclination angle and greater than the minimum inclination
angle.
[0011] 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
[0012] The invention together with objects and advantages thereof,
may best be understood by reference to the following description of
the embodiments together with the accompanying drawings in
which:
[0013] FIG. 1 is a longitudinal cross-sectional view of a
compressor according to a first embodiment of the present
invention, showing a state of a swash plate in its maximum
inclination;
[0014] FIG. 2 is a longitudinal cross-sectional view of the
compressor of FIG. 1, showing a state of the swash plate in its
intermediate inclination;
[0015] FIG. 3 is a longitudinal cross-sectional view of the
compressor of FIG. 1, showing a state of the swash plate in its
minimum inclination;
[0016] FIG. 4 is a fragmentary cross-sectional view of first radial
passages and an axial passage taken along line IV-IV in FIG. 1;
[0017] FIG. 5 is a fragmentary cross-sectional view of second
radial passages and the axial passage taken along line V-V in FIG.
1;
[0018] FIG. 6 is a graph showing a relationship between the
inclination angle of the swash plate and the sum of the opening
areas of the first and the second radial passages, according to the
first embodiment of the present invention; and
[0019] FIG. 7 is a schematic enlarged plan view showing second
radial passages in a compressor according to a second embodiment of
the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0020] The following will describe a variable displacement
single-head swash plate type compressor (hereinafter simply
referred to as the compressor) according to two embodiments of the
present invention with reference to the accompanying drawings. The
compressor according to the embodiments is mounted on a vehicle and
forms a part of a refrigeration circuit of an air conditioner of
the vehicle.
First Embodiment
[0021] Referring to FIGS. 1 to 3, there is shown a compressor
according to a first embodiment. The compressor includes a housing
1, a drive shaft 3, a swash plate 5, a plurality of pistons 7, and
a control mechanism 9.
[0022] In FIG. 1, the left side and the right side of the figure
will be referred to as the front and the rear of the compressor.
The upper side and the lower side of FIG. 1 will be referred to as
the upper and the lower of the compressor. Directions indicated in
FIGS. 2 to 7 excluding FIG. 6 correspond to the directions
indicated in FIG. 1. The directions described in two embodiments
are merely exemplary and the compressor of the present invention
may be mounted appropriately in various postures depending on the
vehicle on which the compressor is mounted.
[0023] The housing 1 includes a first housing member 13, a second
housing member 15, a cylinder block 17, and a valve forming plate
unit 19. The first housing member 13 forms a front part of the
compressor. The second housing member 15 forms a rear part of the
compressor. The cylinder block 17 is disposed between the first
housing member 13 and the second housing member 15.
[0024] The first housing member 13 includes a front wall 13a and a
peripheral wall 13b. The front wall 13a extends in the vertical
direction of the compressor on a front side of the compressor. The
peripheral wall 13b is integrally formed with and extends backward
from the front wall 13a, so that the first housing member 13 is
formed in an approximately cylindrical-bottomed shape by the front
wall 13a and the peripheral wall 13b. The front wall 13a and the
peripheral wall 13b of the first housing member 13 and the cylinder
block 17 cooperate to define a crank chamber 21 in the first
housing member 13.
[0025] The first housing member 13 further has a boss 13c, a first
shaft hole 13d, and a communication passage 13e. The boss 13c
projects forward from the front wall 13a, and has therein a first
accommodation space 130. The first accommodation space 130
spatially extends backward from the front end of the boss 11c. The
boss 13c accommodates a sealing member 23 in the first
accommodation space 130. The first shaft hole 13d extends in the
longitudinal direction of the compressor and connects the first
accommodation space 130 and the crank chamber 21. The first housing
member 13 has a first slide bearing 25a in the first shaft hole
13d.
[0026] The communication passage 13e extends obliquely in the
longitudinal direction of the compressor and connects the first
accommodation space 130 and the crank chamber 21. Specifically, the
front end of the communication passage 13e opens to the first
accommodation space 130 at a position behind the sealing member 23.
The rear end of the communication passage 13e opens to the crank
chamber 21 at a position in front of a lug member 41. Accordingly,
the first accommodation space 130 communicates with the crank
chamber 21 through the communication passage 13e. Details of the
lug member 41 will be described later.
[0027] The second housing member 15 has a suction chamber 15a, a
discharge chamber 15b, an annular wall 15c, an outer peripheral
wall 15d, a suction port 15e, a second accommodation space 15f, and
a discharge port 15g. The suction chamber 15a is defined by the
annular wall 15c and located in the radial center of the second
housing member 15. The discharge chamber 15b is defined by the
annular wall 15c and the outer peripheral wall 15d and is located
radially outward of the suction chamber 15a, so that the discharge
chamber 15b has an annular shape and surrounds the suction chamber
15a.
[0028] The suction port 15e extends in the second housing member 15
in the longitudinal direction of the compressor and opens to
suction chamber 15a at the front end of the suction port 15e. The
suction port 15e opens on the rear surface of the second housing
member 15 at the rear end of the suction port 15e. Accordingly, the
suction port 15e connects the suction chamber 15a and the outside
of the compressor. The second accommodation space 15f communicates
with the discharge chamber 15b and extends in the second housing
member 15 in the longitudinal direction of the compressor. The
discharge port 15g extends vertically in the second housing member
15 and the upper end of the discharge port 15g opens on the upper
surface of the second housing member 15. The discharge port 15g
communicates with the discharge chamber 15b through the second
accommodation space 15f.
[0029] The second housing member 15 includes a discharge check
valve mechanism 27 disposed in the second accommodation space 15f.
The discharge check valve mechanism 27 includes a valve case 27a, a
check valve body 27b, and a first coil spring 27c. The discharge
check valve mechanism 27 is configured to connect or disconnect the
discharge chamber 15b to the outside of the compressor.
[0030] The valve case 27a is fixed inside the second accommodation
space 15f of the second housing member 15 by a circlip 29. The
valve case 27a has a first communication hole 271 and a second
communication hole 272. The first communication hole 271 connects
inside of the valve case 27a and the discharge chamber 15b of the
second housing member 15. The second communication hole 272
connects inside of the valve case 27a and the discharge port 15g.
The check valve body 27b is movably accommodated in the valve case
27a. The first coil spring 27c is disposed in the valve case 27a
and urges the check valve body 27b forward.
[0031] The second housing member 15 has a first feeding passage
31a, a second feeding passage 31b, and a displacement control valve
33. The first feeding passage 31a connects the discharge chamber
15b and the displacement control valve 33. The second feeding
passage 31b is connected to the displacement control valve 33 at
the rear end of the second feeding passage 31b and opens on the
front surface of the second housing member 15 at the front end of
the second feeding passage 31b. The displacement control valve 33
is configured to adjust the opening degree of the first and the
second feeding passages 31a, 31b for adjusting the pressure within
the crank chamber 21 in response to the external control of
supplying electric power. Details of the displacement control valve
33 will be described later.
[0032] The cylinder block 17 has therein a plurality of cylinder
bores 17a. The cylinder bores 17a are arranged circumferentially
and equiangularly. Each of the cylinder bores 17a communicates with
the crank chamber 21 at the front end thereof. The cylinder block
17 further has a retainer groove 17b that determines the maximum
opening degree of a suction reed valve 191a. Details of the suction
reed valve 191a will be described later.
[0033] The cylinder block 17 further has therein a spring chamber
17c, a communication space 17d, a second shaft hole 17e, and a
third feeding passage 31c. The spring chamber 17c extends backward
from the front surface of the cylinder block 17 and communicates
with the crank chamber 21, so that the spring chamber 17c forms a
part of the crank chamber 21. The cylinder block 17 includes a
return spring 35 disposed in the spring chamber 17c. The return
spring 35 urges the swash plate 5 toward the front side of the
crank chamber 21 when the inclination angle of the swash plate 5 is
at the minimum.
[0034] The communication space 17d of the cylinder block 17 extends
forward from the rear surface of the cylinder block 17. The
cylinder block 17 further has a first thrust bearing 37a and a
second coil spring 39 disposed in the communication space 17d. The
second coil spring 39 is interposed between the first thrust
bearing 37a and the valve forming plate unit 19 to support and urge
the first thrust bearing 37a forward. The second shaft hole 17e
longitudinally extends to connect the spring chamber 17c and the
communication space 17d. The cylinder block 17 further has a second
slide bearing 25b disposed in the second shaft hole 17e. The first
and the second slide bearings 25a, 25b may be replaced by rolling
bearings.
[0035] The third feeding passage 31c longitudinally extends in the
cylinder block 17. The third feeding passage 31c opens to the crank
chamber 21 at the front end of the third feeding passage 31c and
opens on the rear surface of the cylinder block 17 at the rear end
of the third feeding passage 31c.
[0036] The valve forming plate unit 19 is disposed between the
cylinder block 17 and the second housing member 15, and includes a
valve plate 190, a suction valve plate 191, a discharge valve plate
192, and a retainer plate 193.
[0037] The valve forming plate unit 19 has the same number of
suction holes 190a and discharge holes 190b as the cylinder bores
17a. The suction holes 190a are formed through the valve plate 190,
the discharge valve plate 192, and the retainer plate 193. The
discharge holes 190b are formed through the valve plate 190 and the
suction valve plate 191. The valve forming plate unit 19 further
has a throttle passage 190c and a third communication hole 190d.
The throttle passage 190c and the third communication hole 190d are
formed through the valve plate 190, the suction valve plate 191,
the discharge valve plate 192, and the retainer plate 193.
[0038] 20
[0039] Each cylinder bore 17a communicates with the suction chamber
15a through the suction hole 190a, and also communicates with the
discharge chamber 15b through the discharge hole 190b. The throttle
passage 190c connects the communication space 17d and the suction
chamber 15a. The third communication hole 190d connects the second
feeding passage 31b and the third feeding passage 31c.
[0040] The suction valve plate 191 is disposed on the front surface
of the valve plate 190, and includes the suction reed valves 191a,
which are elastically deformable so as to open or close the suction
holes 190a. The discharge valve plate 192 is disposed on the rear
surface of the valve plate 190, and has discharge reed valves 192a,
which are elastically deformable so as to open or close the
discharge holes 190b. The retainer plate 193 is disposed on the
rear surface of the discharge valve plate 192 to determine the
maximum opening degree of each discharge reed valve 192a.
[0041] In this compressor, the first to the third feeding passages
31a to 31c and the third communication hole 190d cooperate to form
a feeding passage 31. The second and the third feeding passages
31b, 31c and the third communication hole 190d cooperate to connect
the crank chamber 21 and the displacement control valve 33.
Accordingly, the feeding passage 31 and the displacement control
valve 33 cooperate to connect the crank chamber 21 and the
discharge chamber 15b.
[0042] The drive shaft 3 has an outer peripheral surface 30 and
extends longitudinally through the first housing member 13 and the
cylinder block 17. Specifically, the drive shaft 3 is inserted in
the boss 13c and extends backward longitudinally through the crank
chamber 21 to be inserted in the cylinder block 17. More
specifically, the drive shaft 3 is inserted into the sealing member
23 in the first accommodation space 130 at the front end of the
drive shaft 3. The drive shaft 3 is supported by the first slide
bearing 25a in the first shaft hole 13d and by the second slide
bearing 25b in the second shaft hole 17e. The drive shaft 3 is also
supported by the first thrust bearing 37a in the communication
space 17d at the rear end of the drive shaft 3. Accordingly, the
drive shaft 3 is supported in the crank chamber 21 so as to rotate
about the axis O of the drive shaft 3 that is parallel to the
longitudinal direction of the compressor. The sealing member 23
holds the drive shaft 3 to be rotatable and seals off the crank
chamber 21 from outside of the first housing member 13.
[0043] The drive shaft 3 has a threaded portion 3a at the front end
thereof and is connected to a pulley or an electromagnetic clutch
(not shown) at the threaded portion 3a.
[0044] The drive shaft 3 has thereon the lug member 41, the swash
plate 5, a valve member 43, and a third coil spring 45. The lug
member 41 is press-fit to the drive shaft 3, so that the lug member
41 is rotatable with the drive shaft 3 in the crank chamber 21. The
lug member 41 has a second thrust bearing 37b disposed between the
front wall 13a of the first housing member 13 and the lug c member
41.
[0045] The lug member 41 includes a pair of lug arms 41a. The lug
arms 41a are disposed adjacent to each other and extends backward
from the lug member 41. The lug member 41 further includes a pair
of guide faces 41b disposed between the lug arms 41a. The guide
faces 41b extend obliquely backward from the outer periphery side
of the lug member 41 toward the axis O of the drive shaft 3. The
drawings such as FIG. 1 show one lug arm 41a and one guide face
41b.
[0046] The swash plate 5 is disposed behind the lug member 41 in
the crank chamber 21 such that the lug member 41 faces the swash
plate 5. The swash plate 5 is formed in an approximate disc shape
and has a front surface 5a and a rear surface 5b that face
frontward and rearward, respectively. The swash plate 5 further has
an insertion hole 5c, an abutment portion 5d, and a weight portion
5e.
[0047] The insertion hole 5c passes through the swash plate 5 from
the front surface 5a to the rear surface 5b for receiving the drive
shaft 3, so that the swash plate 5 is supported on the drive shaft
3 for rotation with the drive shaft 3. The abutment portion 5d
projects toward the drive shaft 3 in the insertion hole 5c to abut
on the outer peripheral surface 30 of the drive shaft 3 in the
insertion hole 5c. The weight portion 5e of the swash plate 5 is
formed in an approximate semi-cylindrical shape and extends forward
from the front surface 5a of the swash plate 5. The weight portion
5e includes a pressing surface 500. The pressing surface 500
extends obliquely toward the axis O of the drive shaft 3 and is
formed continuously from the abutment portion 5d in the insertion
hole 5c of the swash plate 5.
[0048] The swash plate 5 further includes a pair of swash plate
arms 5f. The swash plate arms 5f are disposed adjacent to each
other and extend forward from the front surface 5a of the swash
plate 5. The swash plate arms 5f are located opposite to the
abutment portion 5d and the weight portion 5e across the axis O of
the drive shaft 3. The drawings such as FIG. 1 show one of the
swash plate arms 5f.
[0049] In this compressor, the swash plate 5 is mounted on the
drive shaft 3 such that the swash plate arms 5f are located between
the lug arms 41a. The lug member 41 and the swash plate 5 are
coupled to each other such that the swash plate arms 5f are located
between the lug arms 41a. This configuration enables the swash
plate 5 to rotate with the lug member 41 in the crank chamber 21 by
the rotary movement of the drive shaft 3 transmitted through the
lug arms 41a to the swash plate arms 5f.
[0050] The swash plate arms 5f are located between the lug arms
41a, so that the swash plate arms 5f abut and slide on the guide
faces 41b at the front ends of the swash plate arms 5f. This
configuration enables the swash plate 5 to change its inclination
angle to the maximum inclination angle shown in FIG. 1, the
intermediate inclination angle in FIG. 2, or the minimum
inclination angle in FIG. 3 with respect to an imaginary plane
perpendicular to the axis O of the drive shaft 3. The intermediate
inclination angle of the swash plate 5 is an angle that is smaller
than the maximum inclination angle and is greater than the minimum
inclination angle. In this compressor, the intermediate inclination
angle of the swash plate 5 has a certain definite range between the
maximum inclination angle and the minimum inclination angle, more
specifically, the intermediate inclination angle is an angle of the
swash plate 5 while the valve member 43 is covering whole the
openings of the second radial passages 55a to 55c on the outer
peripheral surface 30 of the drive shaft 3. Details of the valve
member 43 will be described later.
[0051] The valve member 43 is formed in a ring shape and has a
front end face 43a, a rear end face 43b, and a tapered surface 43c
formed continuously from the front end face 43a to the rear end
face 43b to decrease the diameter. The valve member 43 is tapered
from the front end face 43a to the rear end face 43b. The valve
member 43 is disposed between the lug member 41 and the swash plate
5. The third coil spring 45 is disposed between the lug member 41
and the front end face 43a of the valve member 43. The drive shaft
3 is inserted into the valve member 43 and the third coil spring
45. The third coil spring 45 urges the valve member 43 backward in
the crank chamber 21. In this compressor, as shown in FIGS. 1 to 3,
the tapered surface 43c of the valve member 43 constantly abuts on
the pressing surface 500 of the swash plate 5 regardless of the
inclination angle of the swash plate 5. This configuration enables
the valve member 43 to axially slide on the outer peripheral
surface 30 of the drive shaft 3 between the lug member 41 and the
swash plate 5 in conjunction with the inclination of the swash
plate 5.
[0052] The pistons 7 are reciprocally movable in the respective
cylinder bores 17a, respectively. Each piston 7 and the valve
forming plate unit 19 cooperate to define a compression chamber 47
in the cylinder bore 17a.
[0053] The pistons 7 each have a recess 7a for engagement. The
recess 7a has therein semi-spherical shoes 49a, 49b. The shoes 49a,
49b serve as a conversion mechanism that is configured to convert
the rotary movement of the swash plate 5 to the reciprocating
movement of the piston 7. This configuration enables the piston 7
to be reciprocally movable in the cylinder bore 17a with a stroke
length depending on the inclination angle of the swash plate 5. The
shoes 49a, 49b may be replaced by a wobble type conversion
mechanism including a thrust bearing for supporting a wobble plate
on the rear surface 5b of the swash plate 5 and connecting rods for
connecting the wobble plate and the pistons 7.
[0054] The drive shaft 3 has therein an axial passage 51, first
radial passages 53a to 53c (FIG. 4), the second radial passages 55a
to 55c (FIG. 5), and a third radial passage 57 (FIGS. 1 to 3).
[0055] The axial passage 51 extends in the drive shaft 3 in the
axial direction of the drive shaft 3 and communicates with the
communication space 17d at the rear end of the axial passage 51.
The axial passage 51 has a larger diameter than that of the
throttle passage 190c.
[0056] The first radial passages 53a to 53c are located in the rear
part of the drive shaft 3. As shown in FIG. 4, each of the first
radial passages 53a to 53c communicates with the axial passage
51and extends from the axial passage 51 in the radial direction of
the drive shaft 3 to open on the outer peripheral surface 30 of the
drive shaft 3 at intervals in the circumferential direction of the
drive shaft 3. Specifically, the first radial passages 53b, 53c
extend in opposite directions, which are perpendicular to the first
radial passage 53a, with respect to the axis O of the drive shaft 3
and open on the outer peripheral surface 30 of the drive shaft 3.
Each of the first radial passages 53a to 53c has a larger diameter
than that of the throttle passage 190c shown in FIGS. 1 to 3.
[0057] The second radial passages 55a to 55c are formed at the
approximate longitudinal center of the drive shaft 3, that is,
disposed in front of the first radial passages 53a to 53c. As shown
in FIG. 5, each of the second radial passages 55a to 55c
communicates with the axial passage 51 and extends from the axial
passage 51 in the radial direction of the drive shaft 3 to open on
the outer peripheral surface 30 of the drive shaft 3 at intervals
in the circumferential direction of the drive shaft 3 as well as
the first radial passages 53a to 53c. Specifically, the second
radial passages 55b, 55c extend in opposite directions, which are
perpendicular to the second radial passage 55a, with respect to the
axis O of the drive shaft 3 and open on the outer peripheral
surface 30 of the drive shaft 3. The second radial passages 55a to
55c each have the same diameter as the first radial passages 53a to
53c, that is, each of the second radial passages 55a to 55c has a
larger diameter than that of the throttle passage 190c shown in
FIGS. 1 to 3.
[0058] As shown in FIG. 1, the third radial passage 57 is formed in
the front part of the drive shaft 3 in front of the first and
second radial passages 53a to 53c, 55a to 55c. The third radial
passage 57 communicates with the axial passage 51 and extends from
the axial passage 51 in the radial direction of the drive shaft 3
to open on the outer peripheral surface 30 of the drive shaft 3.
The third radial passage 57 has the same diameter as each of the
first and second radial passages 53a to 53c, 55a to 55c, that is,
the third radial passage 57 has a larger diameter than that of the
throttle passage 190c.
[0059] In this compressor, the drive shaft 3 is inserted into the
first housing member 13 and the cylinder block 17, so that the
first radial passages 53a to 53c are positioned in the spring
chamber 17c, that is, positioned on the rear side of the crank
chamber 21. The first radial passages 53a to 53c are in constant
communication with the crank chamber 21.
[0060] When the swash plate 5 is at the maximum inclination angle,
the second radial passages 55a to 55c are positioned in the
insertion hole 5c of the swash plate 5 at the approximate
longitudinal center of the crank chamber 21, in other words, the
second radial passages 55a to 55c open on the outer peripheral
surface 30 of the drive shaft 3 in the crank chamber 21 at
positions that are closer to the swash plate 5 than the first
radial passages 53a to 53c are to the swash plate 5. The first
radial passages 53a to 53c open on the outer peripheral surface 30
of the drive shaft 3 in the crank chamber 21 at positions that are
closer to the cylinder bores 17a than the second radial passages
55a to 55c are to the cylinder bores 17a.
[0061] The drive shaft 3 and the swash plate 5 are positioned such
that the second radial passages 55a to 55c and the abutment portion
5d do not face each other in the insertion hole 5c of the swash
plate 5. That is, the second radial passages 55a to 55c open on the
outer peripheral surface 30 of the drive shaft 3 at positions that
are spaced from the abutment portion 5d in the circumferential
direction of the drive shaft 3. In this compressor, the second
radial passages 55a to 55c are connected to or disconnected from
the crank chamber 21 by the axial movement of the valve member 43
on the drive shaft 3. This connecting system between the second
radial passages 55a to 55c and the crank chamber 21 will be
described later.
[0062] The third radial passage 57 is positioned in the first
accommodation space 130, specifically, positioned between the
sealing member 23 and the lug member 41. The first accommodation
space 130 communicates with the crank chamber 21 through the
communication passage 13e, so that the third radial passage 57 in
the first accommodation space 130 is in constant communication with
the crank chamber 21.
[0063] In this compressor, the axial passage 51, the first radial
passages 53a to 53c, the second radial passages 55a to 55c, the
third radial passage 57, the communication space 17d, and the
throttle passage 190c cooperate to form a bleeding passage 59, so
that the crank chamber 21 communicates with the suction chamber 15a
through the bleeding passage 59. The feeding passage 31, the
bleeding passage 59 and the displacement control valve 33 cooperate
to form the control mechanism 9.
[0064] In this compressor, the suction port 15e is connected to an
evaporator through a pipe. The discharge port 15g is connected to a
condenser through a pipe. The evaporator and the condenser are
connected through the pipes and an expansion valve. The evaporator,
the expansion valve, the condenser, and the compressor cooperate to
form a refrigeration circuit of a vehicle air conditioner. The
evaporator, the expansion valve, the condenser, and the pipes are
not shown in the drawings.
[0065] In this compressor, each piston 7 makes a reciprocating
movement in the cylinder bore 17a in response to the rotation of
the swash plate 5 caused by the rotary movement of the drive shaft
3. The compression chamber 47 changes its volume depending on the
stroke length of the piston 7. The refrigerant gas, which flows
from the evaporator into the suction chamber 15a through the
suction port 15e, is introduced from the suction chamber 15a into
the compression chamber 47 to be compressed. The compressed
refrigerant gas is discharged from the compression chamber 47 to
the discharge chamber 15b, and then discharged to the condenser
through the discharge port 15g. When the pressure within the
discharge chamber 15b is below a predetermined pressure value, as
shown in FIG. 3, the first coil spring 27c urges the check valve
body 27b to close the first and the second communication holes 271,
272 so as to prevent the back-flow of the refrigerant gas from the
condenser to the discharge chamber 15b. However, the check valve
body 27b may not completely close the first and the second
communication holes 271, 272 so as to discharge a small flow rate
of refrigerant gas, which is discharged from the compression
chamber 47 to the discharge chamber 15b, to the condenser.
[0066] In this compressor, the control mechanism 9 is configured to
adjust the pressure within the crank chamber 21 so as to adjust the
discharge volume of the compressor.
[0067] Specifically, the displacement control valve 33 of the
control mechanism 9 adjusts the opening degree of the feeding
passage 31, which is formed by the first to the third feeding
passages 31a to 31c and the third communication hole 190d. The
refrigerant gas at high pressure is introduced from the discharge
chamber 15b into the crank chamber 21 through the feeding passage
31. Then, the refrigerant gas in the crank chamber 21 is introduced
into the suction chamber 15a through the bleeding passage 59, which
is formed by the axial passage 51, the first radial passages 53a to
53c, the second radial passages 55a to 55c, the third radial
passage 57, the communication space 17d and the throttle passage
190c. The adjustment of the opening degree by the displacement
control valve 33 of the control mechanism 9 controls the balance
between the flow rate of the high pressure refrigerant gas
introduced from the discharge chamber 15b into the crank chamber 21
through the feeding passage 31 and the flow rate of the refrigerant
gas introduced from the crank chamber 21 into the suction chamber
15a through the bleeding passage 59. The balance between these two
flow rates determines the pressure within the crank chamber 21. The
change in the pressure within the crank chamber 21 varies the
differential pressure between the crank chamber 21 and the
compression chambers 47, thereby changing the inclination angle of
the swash plate 5. The inclination angle of the swash plate 5
determines the stroke length of each piston 7 to adjust the
discharge volume of the compressor.
[0068] Accordingly, in this compressor, the pressure within the
crank chamber 21 increases as the displacement control valve 33
increases the opening degree of the feeding passage 31, so that the
swash plate 5 decreases its inclination angle with the abutment
portion 5d abutting on the outer peripheral surface 30 of the drive
shaft 3. The decreasing inclination angle of the swash plate 5
decreases the stroke length of each piston 7, thereby decreasing
the discharge volume per rotation of the drive shaft 3. Conversely,
the pressure within the crank chamber 21 decreases as the
displacement control valve 33 decreases the opening degree of the
feeding passage 31, so that the swash plate 5 increases its
inclination angle with the abutment portion 5d abutting on the
outer peripheral surface 30 of the drive shaft 3. The increasing
inclination angle of the swash plate 5 increases the stroke length
of each piston 7, thereby increasing the discharge volume per
rotation of the drive shaft 3.
[0069] In this compressor, the drive shaft 3 has therein the first
radial passages 53a to 53c, the second radial passages 55a to 55c,
and the third radial passage 57 that communicate with the axial
passage 51, and the refrigerant gas in the crank chamber 21 is
introduced into the suction chamber 15a through the first radial
passages 53a to 53c and the second radial passages 55a to 55c. This
configuration enables the flow rate control of the refrigerant gas
introduced from the third radial passage 57 to the axial passage
51. The throttle passage 190c has a smaller diameter than those of
the axial passage 51, the first radial passages 53a to 53c, the
second radial passages 55a to 55c and the third radial passage 57,
so that the throttle passage 190c enables to lead the refrigerant
gas to the suction chamber 15a at a preferred pressure.
[0070] In this compressor, each cylinder bore 17a positioned
adjacent to the rear part of the crank chamber 21 leaks blow-by gas
containing a relatively large amount of lubricant, so that the
refrigerant gas presents in the rear part of the crank chamber 21
contains a relatively large amount of lubricant. The lubricant is
sprinkled by the rotation of the drive shaft 3 and the swash plate
5 radially and outwardly in the crank chamber 21, and flows down in
the crank chamber 21 from the peripheral wall 13b to the front wall
13a, so that the plenty of lubricant presents in the front part of
the crank chamber 21. That is, the refrigerant gas in the front
part of the crank chamber 21 contains larger amount of lubricant
than the refrigerant gas in the rear part of the crank chamber 21.
On the other hand, the lubricant in the refrigerant gas existing
around the longitudinal center of the crank chamber 21,
specifically, the lubricant in the refrigerant gas existing around
the insertion hole 5c of the swash plate 5 is reduced because the
lubricant is sprinkled by the rotation of the drive shaft 3 and the
swash plate 5 radially and outwardly in the crank chamber 21.
[0071] Accordingly, the refrigerant gas flowing from the
communication passage 13e through the third radial passage 57 to
the axial passage 51 contains larger amount of lubricant than the
refrigerant gas introduced from the first radial passages 53a to
53c or the second radial passages 55a to 55c to the axial passage
51. The refrigerant gas introduced from the first radial passages
53a to 53c to the axial passage 51 contains larger amount of
lubricant than the refrigerant gas introduced from the second
radial passages 55a to 55c to the axial passage 51. In other words,
the refrigerant gas introduced from the second radial passages 55a
to 55c to the axial passage 51 contains the smallest amount of
lubricant.
[0072] In this compressor, the refrigerant gas containing the
lubricant in the crank chamber 21 is introduced into the suction
chamber 15a through the third radial passage 57, the axial passage
51, the communication space 17d, and the throttle passage 190c to
adjust the pressure within the crank chamber 21, so that the
lubricant in the refrigerant gas suitably lubricates the second
thrust bearing 37b, the sealing member 23 and the first slide
bearing 25a. Particularly, the sealing member 23 is lubricated
constantly because the third radial passage 57 is in constant
communication with the crank chamber 21 through the first
accommodation space 130 and the communication passage 13e.
[0073] In this compressor, the valve member 43 moves on the drive
shaft 3 in the axial direction of the drive shaft 3 in conjunction
with the inclination of the swash plate 5, so that the sum of the
opening areas of the first radial passages 53a to 53c and the
second radial passages 55a to 55c changes depending on the
inclination angle of the swash plate 5 as shown in FIG. 6.
Specifically, the sum of the opening areas of the first radial
passages 53a to 53c and the second radial passages 55a to 55c
reaches the maximum level at the minimum inclination angle or the
maximum inclination angle of the swash plate 5. The sum of the
opening areas gradually decreases with the increasing inclination
angle of the swash plate 5 from the minimum inclination angle to
the intermediate inclination angle. The sum of the opening areas is
kept to the minimum level while the swash plate 5 is at the
intermediate inclination angle. Then, the sum of the opening areas
gradually increases with the increasing inclination angle of the
swash plate 5 from the intermediate inclination angle to the
maximum inclination angle. In this compressor, since the first
radial passages 53a to 53c are in constant communication with the
crank chamber 21, the opening areas of the first radial passages
53a to 53c are maintained constant, which does not reduce the sum
of the opening areas of the first radial passages 53a to 53c and
the second radial passages 55a to 55c to zero. The operation
according to the change in the sum of the opening areas of the
first radial passages 53a to 53c and the second radial passages 55a
to 55c is described below.
[0074] In this compressor, as shown in FIG. 1, when the inclination
angle of the swash plate 5 is at the maximum, the pressing surface
500 presses the valve member 43 on the drive shaft 3 axially toward
the front part of the crank chamber 21 to move the valve member 43
away from the openings of the second radial passages 55a to 55c on
the outer peripheral surface 30 of the drive shaft 3. That is, when
the inclination angle of the swash plate 5 is at the maximum, the
second radial passages 55a to 55c are connected to the crank
chamber 21 and reach their maximum opening areas as described
above. Accordingly, the refrigerant gas in the crank chamber 21 is
introduced from each of the first radial passages 53a to 53c, the
second radial passages 55a to 55c, and the third radial passage 57
into the suction chamber 15a through the axial passage 51, the
communication space 17d, and the throttle passage 190c. When the
sum of the opening areas of the first radial passages 53a to 53c
and the second radial passages 55a to 55c is maximum, this
compressor enables the reduction of the flow rate of the
refrigerant gas introduced through the third radial passage 57 into
the suction chamber 15a while ensuring the overall flow rate of the
refrigerant gas introduced from the crank chamber 21 into the
suction chamber 15a. Also, this compressor enables the decrease of
the flow rate of the refrigerant gas introduced through the first
radial passages 53a to 53 since the refrigerant gas is introduced
through the second radial passages 55a to 55c in addition to the
first radial passages 53a to 53c.
[0075] Since the refrigerant gas introduced through the second
radial passages 55a to 55c from the crank chamber 21 contains only
a small amount of lubricant as described above, the lubricant is
not excessively introduced with the refrigerant gas through the
second radial passages 55a to 55c into the suction chamber 15a when
the second radial passages 55a to 55c are connected to the crank
chamber 21, and the certain amount of the lubricant is secured in
the crank chamber 21. Accordingly, when the inclination angle of
the swash plate 5 is at the maximum, this compressor enables the
reduction of the lubricant introduced from the crank chamber 21
into the suction chamber 15a while lubricating the sealing member
23 by the lubricant in the refrigerant gas introduced through the
third radial passage 57. This compressor is unlikely to cause the
insufficient lubrication in the crank chamber 21 when the
inclination angle of the swash plate 5 is at the maximum.
[0076] In this compressor, the valve member 43 axially moves on the
drive shaft 3 toward the rear part of the crank chamber 21 in
conjunction with the decreasing inclination angle of the swash
plate 5 from the maximum to gradually cover the openings of the
second radial passages 55a to 55c on the outer peripheral surface
30 of the drive shaft 3, so that the sum of the opening areas of
the first radial passages 53a to 53c and the second radial passages
55a to 55c gradually decreases as shown in FIG. 6 as the opening
areas of the second radial passages 55a to 55c gradually decrease.
Accordingly, the flow rate of the refrigerant gas introduced from
the third radial passage 57 to the axial passage 51 gradually
increases. As shown in FIG. 2, while the swash plate 5 is at the
intermediate inclination angle, the valve member 43 covers the
whole openings of the second radial passages 55a to 55c, and the
second radial passages 55a to 55c are disconnected from the crank
chamber 21 by the valve member 43 on the drive shaft 3. While the
swash plate 5 is at the intermediate inclination angle, the
refrigerant gas is not introduced from the crank chamber 21 into
the suction chamber 15a through the second radial passages 55a to
55c and the axial passage 51.
[0077] In this compressor, when the sum of the opening areas of the
first radial passages 53a to 53c and the second radial passages 55a
to 55c is minimum, the flow rate of the refrigerant gas introduced
from the third radial passage 57 to the axial passage 51 increases,
thus, the lubricant in the refrigerant gas introduced from the
third radial passage 57 lubricates the sealing member 23 in the
first accommodation space 130 suitably. As the opening areas of the
second radial passages 55a to 55c gradually decrease, the flow rate
of the refrigerant gas introduced from the first radial passages
53a to 53c to the axial passage 51 gradually increases. As a
result, when the swash plate 5 is at the intermediate inclination
angle, this compressor prevents or inhibits the excessive
accumulation of the lubricant in the crank chamber 21 and the heat
generation of the lubricant caused by the agitation by the swash
plate 5 in the crank chamber 21. The prevention of the excessive
lubricant accumulation in the crank chamber 21 enables this
compressor to eliminate or minimize the insufficient circulation of
the lubricant in the refrigeration circuit in which this compressor
is included.
[0078] In this compressor, the valve member 43 further moves
axially on the drive shaft 3 toward the rear part of the crank
chamber 21 and gradually away from the openings of the second
radial passages 55a to 55c on the outer peripheral surface 30 of
the drive shaft 3 with the decreasing inclination angle of the
swash plate 5 from the intermediate inclination angle, so that the
opening areas of the second radial passages 55a to 55c gradually
increase as the second radial passages 55a to 55c gradually open to
the crank chamber 21. As shown in FIG. 3, when the inclination
angle of the swash plate 5 is at the minimum, the valve member 43
is completely away from the openings of the second radial passages
55a to 55c and the second radial passages 55a to 55c reach their
maximum opening areas, thus, the sum of the opening areas of the
first radial passages 53a to 53c and the second radial passages 55a
to 55c reaches the maximum level. That is, as well as the case for
the maximum inclination angle, when the inclination angle of the
swash plate 5 is at the minimum, this compressor enables the
decrease of the flow rate of the refrigerant gas introduced through
the third radial passage 57 into the suction chamber 15a while
ensuring decreasing the overall flow rate of the refrigerant gas
introduced from the crank chamber 21 into the suction chamber 15a.
Accordingly, this compressor enables the reduction of the lubricant
introduced from the crank chamber 21 to the suction chamber 15a
while ensuring the overall flow rate of the refrigerant gas
introduced from the crank chamber 21 into the suction chamber
15a.
[0079] When the discharge volume per rotation of the drive shaft 3
is reduced at the minimum inclination angle of the swash plate 5,
this compressor may slightly flow the refrigerant gas, which was
discharged from the compression chamber 47 to the discharge chamber
15b, to the condenser. In this case, the lubricant, which was
introduced with the refrigerant gas from the crank chamber 21 to
the suction chamber 15a, is to the compression chamber 47 and then
discharger) to the condenser through the discharge chamber 15b.
When the inclination angle of the swash plate 5 is at the minimum,
the lubricant flowing into the compressor with the refrigerant gas
decreases because the flow rate of the refrigerant gas flowing from
the evaporator into the suction chamber 15a through the suction
port 15e decreases. However, even in this case, this compressor is
unlikely to cause the insufficient lubrication in the crank chamber
21.
[0080] In the adjustment of the pressure within the crank chamber
21, this compressor enables the suitable control of the amount of
the lubricant introduced with the refrigerant gas from the crank
chamber 21 to the suction chamber 15a while ensuring the flow rate
of the refrigerant gas introduced from the crank chamber 21 to the
suction chamber 15a through the bleeding passage 59. Therefore,
this compressor is capable of securing the lubricant in the crank
chamber 21 depending on the inclination angle of the swash plate
5.
[0081] Accordingly, the compressor according to the first
embodiment exhibits higher durability and controllability.
[0082] Particularly, this compressor has the first radial passages
53a to 53c in the drive shaft 3. This configuration enables the
suitable control of the flow rate of the refrigerant gas introduced
from the crank chamber 21 into the suction chamber 15a through the
first radial passages 53a to 53c and the axial passage 51. This
compressor further has the second radial passages 55a to 55c in the
drive shaft 3. This configuration enables the suitable control of
the flow rate of the refrigerant gas introduced from the crank
chamber 21 to the suction chamber 15a through the second radial
passages 55a to 55c and the axial passage 51 when the second radial
passages 55a to 55c are connected to the crank chamber 21.
[0083] In this compressor, the openings of the second radial
passages 55a to 55c are located away from the abutment portion 5d
in the circumferential direction of the drive shaft 3, so that the
openings of the second radial passages 55a to 55c do not face the
abutment portion 5d, or, do not contact the abutment portion 5d in
the insertion hole 5c of the swash plate 5. This configuration
enables the suitable change of the inclination angle of the swash
plate 5.
Second Embodiment
[0084] As shown in FIG. 7, the compressor according a second
embodiment has three second radial passages, namely, second radial
passages 61a to 61c in the drive shaft 3. As well as the second
radial passages 55a to 55c according to the first embodiment, each
of the second radial passages 61a to 61c communicates with the
axial passage 51 and extends from the axial passage 51 in the
radial direction of the drive shaft 3 to open on the outer
peripheral surface 30 of the drive shaft 3 at the approximate
longitudinal center of the drive shaft 3. The second radial passage
61a has a larger diameter than those of the second radial passages
61b, 61c and is disposed behind the second radial passages 61b, 61c
in the axial direction of the drive shaft 3. In this compressor,
the second radial passages 61a to 61c are formed at positions where
whole the second radial passages 61a to 61c are covered by the
valve member 43 while the swash plate 5 is at the intermediate
inclination angle. The structure of the compressor according to the
second embodiment is otherwise similar to the compressor according
to the first embodiment and will not be further elaborated
here.
[0085] According to the second embodiment, the second radial
passage 61a has a larger diameter than those of the second radial
passages 61b, 61c. This configuration enables the suitable
adjustment of the opening degree of the second radial passages 61a
to 61c along with the axial movement of the valve member 43. The
operation of the compressor according to the second embodiment is
otherwise similar to the compressor according to the first
embodiment and will not be further elaborated here.
[0086] Although the present invention is described with the first
and the second embodiments, the present invention is not limited
thereto, and the invention may appropriately be modified within the
gist of the present invention.
[0087] For example, instead of the third radial passage 57, the
first radial passages 53a to 53c may be formed in the front part of
the drive shaft 3 to open between the sealing member 23 and the lug
member 41 on the outer peripheral surface 30 of the drive shaft
3.
[0088] The first radial passage of the present invention may be
formed by the first radial passages 53a only without the first
radial passages 53b, 53c. The drive shaft 3 may have an additional
first radial passage other than the first radial passages 53a to
53c. The second radial passage of the present invention may be
formed by the second radial passages 55a only without the second
radial passages 55b, 55c. The drive shaft 3 may have an additional
second radial passage other than the second radial passages 55a to
55c. The drive shaft 3 may have an additional third radial passage
other than the third radial passage 57.
[0089] In the compressor according to the first embodiment, the
first radial passages 53a to 53c, the second radial passages 55a to
55c, and the third radial passage 57 have the same diameter.
According to the present invention; however, each of the first
radial passages 53a to 53c may have a lager diameter than those of
the second radial passages 55a to 55c and the third radial passage
57. Each of the second radial passages 55a to 55c may have a lager
diameter than those of the first radial passages 53a to 53c and the
third radial passage 57. The third radial passage 57 may have a
lager diameter than those of the first radial passages 53a to 53c
and the second radial passages 55a to 55c.
[0090] In the compressor according to the first embodiment, the
displacement control valve 33 adjusts the opening degree of the
feeding passage 31. The compressor may have, however, a
displacement control valve which is configured to adjust the
opening degree of the bleeding passage 59.
[0091] The present invention is applicable to air conditioners.
* * * * *