U.S. patent application number 12/362713 was filed with the patent office on 2009-09-03 for swash plate compressor.
Invention is credited to Sokichi Hibino, Masahiro Kawaguchi, Hideki Mizutani, Masakazu Murase, Takeshi Ogi, Masaki Ota, Kenji Yamamoto, Naoya Yokomachi.
Application Number | 20090220355 12/362713 |
Document ID | / |
Family ID | 40652870 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090220355 |
Kind Code |
A1 |
Ogi; Takeshi ; et
al. |
September 3, 2009 |
SWASH PLATE COMPRESSOR
Abstract
The invention has its object to provide a swash plate compressor
capable of realizing demonstration of an excellent sliding
characteristic when a drive shaft is rotated at high speed, and of
a high refrigerating capacity when the drive shaft is rotated at
low speed. With the swash plate compressor of the invention, an oil
guide groove, an oil guide hole, a first hole, an outflow hole, a
valve hole, a communication port, a receiving chamber, a throttle
hole, and a second hole constitute a release passage. The oil guide
groove, the oil guide hole, the first hole, the outflow hole, the
valve hole, the communication port, the receiving chamber, and the
throttle hole constitute a first passage. Also, the second hole
constitute a second passage. A valve mechanism increases a ratio,
at which the first passage occupies the release passage, as a drive
shaft is increased in rotating speed.
Inventors: |
Ogi; Takeshi; (Kariya-shi,
JP) ; Mizutani; Hideki; (Kariya-shi, JP) ;
Hibino; Sokichi; (Kariya-shi, JP) ; Yamamoto;
Kenji; (Kariya-shi, JP) ; Kawaguchi; Masahiro;
(Kariya-shi, JP) ; Ota; Masaki; (Kariya-shi,
JP) ; Murase; Masakazu; (Kariya-shi, JP) ;
Yokomachi; Naoya; (Kariya-shi, JP) |
Correspondence
Address: |
Locke Lord Bissell & Liddell LLP;Attn: IP Docketing
Three World Financial Center
New York
NY
10281-2101
US
|
Family ID: |
40652870 |
Appl. No.: |
12/362713 |
Filed: |
January 30, 2009 |
Current U.S.
Class: |
417/222.1 |
Current CPC
Class: |
F04B 39/0223 20130101;
F04B 27/1009 20130101; F04B 53/18 20130101; F04B 27/109 20130101;
F04B 2027/1831 20130101 |
Class at
Publication: |
417/222.1 |
International
Class: |
F04B 27/18 20060101
F04B027/18 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 5, 2008 |
JP |
2008-025757 |
Feb 20, 2008 |
JP |
2008-038686 |
Mar 3, 2008 |
JP |
2008-052548 |
Claims
1. A swash plate compressor comprising: a housing including a
cylinder bore, a suction chamber, a discharge chamber and a crank
chamber, a drive shaft rotatably supported by the housing, a swash
plate supported on the drive shaft in the crank chamber, a piston
reciprocatingly accommodated in the cylinder bore, a motion
conversion mechanism provided between the swash plate and the
piston to convert wobbling motion of the swash plate into
reciprocation of the piston, and a release passage for
communication of the crank chamber to the suction chamber, the
compressor being characterized in that the release passage includes
a first passage communicated to an oil rich region, in which
lubricating oil is large in quantity in the crank chamber, a valve
mechanism is provided to increase opening degree of the first
passage as the drive shaft is increased in rotating speed, and the
valve mechanism is provided on the first passage to be displaced by
centrifugal force.
2. The swash plate compressor according to claim 1, wherein the
release passage includes a second passage communicated to an oil
poor region, in which the lubricating oil is small in quantity in
the crank chamber, and the valve mechanism increases a ratio, at
which the first passage occupies the release passage, as the drive
shaft is increased in rotating speed, and decreases a ratio, at
which the second passage occupies the release passage, as the drive
shaft is decreased in rotating speed.
3. The swash plate compressor according to claim 2, wherein the
second passage is formed with a throttle.
4. The swash plate compressor according to claim 2, wherein the
swash plate is supported to be variable in inclination angle, a lug
plate receiving compressive reaction force is fixed to the drive
shaft and rotates integrally with the drive shaft, an oil guide
path is formed on the housing to extend between the housing and the
lug plate from an outer peripheral region of the crank chamber, and
the first passage is communicated to the oil guide path.
5. The swash plate compressor according to claim 4, wherein a shaft
seal device is provided to seal between the housing and the drive
shaft, and the first passage is communicated to the oil guide path
at a position close to the shaft seal device.
6. The swash plate compressor according to claim 2, wherein the
swash plate is supported to be variable in inclination angle, a lug
plate receiving compressive reaction force is fixed to the drive
shaft and rotates integrally with the drive shaft, and the first
passage includes a guide hole formed on the lug plate and opened to
an outer peripheral region of the crank chamber.
7. The swash plate compressor according to claim 6, wherein a shaft
seal device is provided to seal between the housing and the drive
shaft, and the second passage is opened to the crank chamber in the
vicinity of the shaft seal device.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority to Japanese
Patent Application No. 2008-25757, filed on Feb. 5, 2008, No.
2008-38686, filed on Feb. 20, 2008, and No. 2008-52548, filed on
Mar. 3, 2008, the contents of which are hereby incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a swash plate
compressor.
[0003] JP-A-8-284816 discloses a conventional swash plate
compressor. The swash plate compressor includes a housing composed
of a front housing, a cylinder block and a rear housing, and the
housing defines a plurality of cylinder bores, a suction chamber, a
discharge chamber and a crank chamber therein. The front housing
rotatably supports a drive shaft, one end of which is exposed from
the front housing. In the crank chamber, a swash plate is supported
by the drive shaft so as to vary its inclination angle. Pistons are
reciprocatingly received in the respective cylinder bores. Pairs of
front and rear shoes are provided between the swash plate and the
respective pistons for converting wobbling motions of the swash
plate into reciprocation of the respective pistons. A supply
passage provides communication between the discharge chamber and
the crank chamber and a capacity control valve is provided on the
supply passage to regulate pressure in the crank chamber.
[0004] Also, the swash plate compressor is formed with a release
passage, which communicates the crank chamber to the suction
chamber. With the swash plate compressor disclosed in the
aforementioned patent application publication, the release passage
includes a first radial hole formed to extend radially of the drive
shaft, and an outflow hole which communicates the first radial hole
to the suction chamber. A lug plate is fixed to the drive shaft in
a manner to rotate together therewith and an oil supply passage is
formed on the lug plate to extend toward a center from an outer
peripheral region of the crank chamber. Also, a shaft seal device
is provided to seal between the front housing and the drive shaft,
and a lubrication passage is formed on the front housing to
communicate the oil supply passage to the first radial hole at a
location where the shaft seal device is provided.
[0005] The swash plate compressor together with a condenser, an
expansion valve, and an evaporator constitutes a refrigerating
circuit, and the refrigerating circuit is used air-conditioning
apparatus for a vehicle. With the swash plate compressor, the
capacity control valve adjusts pressure in the crank chamber on the
basis of pressure in the suction chamber or a flow rate of
refrigerating gas to change an angle of the swash plate with
respect to the drive shaft to thereby change a discharge capacity
thereof.
[0006] Also, with the swash plate compressor, in an outer
peripheral region of the crank chamber, lubricating oil is present
in abundance in the crank chamber, and the release passage composed
of the oil supply passage, the lubrication passage, the first
radial hole and the outflow hole is communicated to that region, in
which the lubricating oil is present in abundance, so that it is
possible to supply the lubricating oil in the crank chamber to the
shaft seal device, thus enabling improving durability of a rubber
material for the shaft seal device.
[0007] With a swash plate compressor, when a drive shaft is rotated
at high speed, an improvement in sliding characteristic is demanded
between cylinder bores and pistons, and between a swash plate and
respective shoes, and so on. Also, when a drive shaft is rotated at
low speed, lubricating oil in refrigerating gas discharged to an
external refrigerating circuit outside a swash plate compressor is
demanded of reduction in quantity to demonstrate a high
refrigerating capacity.
[0008] In this respect, with the swash plate compressor disclosed
in the aforementioned patent application publication, the release
passage communicates an oil rich region, in which lubricating oil
is present in abundance in the crank chamber, in a predetermined
cross sectional area with the suction chamber at all times, so that
the lubricating oil in the crank chamber is made excessively small
or large in quantity irrespective of the rotating speed of the
drive shaft. When the lubricating oil in the crank chamber is
excessively large in quantity while the drive shaft is increased in
rotating speed, the swash plate agitates the lubricating oil
excessively, so that the lubricating oil is liable to generate heat
due to shearing and to decrease in viscosity. In this case, there
is a fear in lubrication of sliding portions. Also, when the
lubricating oil in the crank chamber is excessively small in
quantity while the drive shaft is decreased in rotating speed, the
lubricating oil in refrigerating gas discharged to a refrigerating
circuit outside the swash plate compressor is increased in quantity
and so the refrigerating capacity becomes insufficient.
SUMMARY OF THE INVENTION
[0009] An object of the invention is to provide a swash plate
compressor capable of realizing an excellent sliding characteristic
when a drive shaft is rotated at high speed, and a high
refrigerating capacity when the drive shaft is rotated at low
speed.
[0010] Refrigerating gas mixed with lubricating oil is adopted in a
swash plate compressor. According to experiments conducted by the
inventors of the present invention, there are present an oil rich
region, in which the lubricating oil is large in quantity, and an
oil poor region, in which the lubricating oil is small in quantity,
in a crank chamber of a swash plate compressor. For example, the
oil rich region is present in an outer peripheral region of the
crank chamber, and the oil poor region is present in an inner
peripheral region of the crank chamber, that is, a region away from
a wall surface of the crank chamber. This is because a swash plate
rotates together with a drive shaft in the crank chamber and the
lubricating oil is forced out into the outer peripheral region of
the crank chamber by centrifugal force. Also, the lubricating oil
is present in abundance on a peripheral surface of a cylinder bore.
The invention has been accomplished based on these
ascertainments.
[0011] The invention provides a swash plate compressor comprising:
a housing including a cylinder bore, a suction chamber, a discharge
chamber and a crank chamber, a drive shaft rotatably supported by
the housing, a swash plate supported on the drive shaft in the
crank chamber, a piston reciprocatingly accommodated in the
cylinder bore, a motion conversion mechanism provided between the
swash plate and the piston to convert a wobbling motion of the
swash plate into reciprocation of the piston, and a release passage
for communication of the crank chamber to the suction chamber, the
compressor being characterized in that the release passage includes
a first passage communicated to an oil rich region, in which
lubricating oil is large in quantity in the crank chamber, a valve
mechanism is provided to increase opening degree of the first
passage as the drive shaft is increased in rotating speed, and the
valve mechanism is provided on the first passage to be displaced by
centrifugal force.
[0012] With the swash plate compressor of the invention, when the
drive shaft is rotated at high speed, the valve mechanism increases
opening degree of the first passage. Therefore, refrigerating gas
containing a large quantity of the lubricating oil in the crank
chamber is moved to the suction chamber by the first passage,
opening degree of which is increased. Therefore, the lubricating
oil in the crank chamber becomes moderate in quantity and so the
swash plate does not agitate the lubricating oil so much, so that
the lubricating oil is hard to generate heat due to shearing and
hard to decrease in viscosity. Therefore, sliding portions are
favorably lubricated. Also, refrigerating gas sucked from the
suction chamber contains a large quantity of the lubricating oil
and sliding portions between the cylinder bore and the piston are
favorably lubricated. In addition, while the lubricating oil
contained in refrigerating gas discharged to a refrigerating
circuit outside the swash plate compressor are increased in
quantity at this time, no problem is caused in refrigerating
capacity since the piston reciprocates at high speed.
[0013] In addition, with the swash plate compressor, while the
lubricating oil in the crank chamber is increased in quantity when
the drive shaft is rotated at low speed, the swash plate or the
like only agitates the lubricating oil at low speed, so that the
lubricating oil is not decreased so much in viscosity and the
lubricating oil is little raised in temperature. Therefore, sliding
portions are still lubricated favorably.
[0014] The valve mechanism is provided on the first passage to be
displaced by the centrifugal force. A mechanical valve mechanism is
adopted, in which a mass body is displaced by the centrifugal force
and a valve body is actuated. Therefore, an increase in the
centrifugal force causes a displacement in a direction, in which
the first passage is increased in opening degree, and a decrease in
the centrifugal force causes a displacement in a direction, in
which the first passage is decreased in opening degree.
[0015] Accordingly, with the swash plate compressor of the
invention, it is possible to realize an excellent sliding
characteristic when a drive shaft is rotated at high speed, and a
high refrigerating capacity when the drive shaft is rotated at low
speed.
[0016] Other aspects and advantages of the invention will be
apparent from embodiments disclosed in the attached drawings,
illustrations exemplified therein, and the concept of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention will be described in more detail along with
the concept and advantages thereof by referring to the attached
drawings and the detailed description of the preferred embodiments
below.
[0018] FIG. 1 is a cross sectional view showing a swash plate
compressor according to EMBODIMENT 1.
[0019] FIG. 2 relates to the swash plate compressor according to
EMBODIMENT 1 and is a cross sectional view showing an essential
part thereof.
[0020] FIG. 3 relates to the swash plate compressor according to
EMBODIMENT 1 and is a cross sectional view showing, in enlarged
scale, an essential part thereof while a drive shaft is rotated at
low speed.
[0021] FIG. 4 relates to the swash plate compressor according to
EMBODIMENT 1 and is a cross sectional view showing, in enlarged
scale, an essential part thereof while the drive shaft is rotated
at high speed.
[0022] FIG. 5 relates to the swash plate compressor according to
EMBODIMENT 1 and is a graph illustrating the relationship between
the rotating speed of the drive shaft and a throttle area.
[0023] FIG. 6 is a cross sectional view showing a swash plate
compressor according to EMBODIMENT 2.
[0024] FIG. 7 is a cross sectional view showing a swash plate
compressor of a modified example.
[0025] FIG. 8 is a cross sectional view showing a swash plate
compressor of a further modified example.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Embodiments 1 and 2, in which the invention is embodied,
will be described below with reference to the drawings.
Embodiment 1
[0027] A swash plate compressor according to EMBODIMENT 1 is of a
variable displacement type used for air-conditioning of a vehicle.
As shown in FIG. 1, the compressor includes a housing composed of a
cylinder block 1, a front housing 3 and a rear housing 5, and a
plurality of cylinder bores 1a extending in parallel to an axis of
a drive shaft 7 are provided on the cylinder block 1 to extend
therethrough. In addition, the left in FIG. 1 indicates the front
of the compressor and the right indicates the rear of the
compressor.
[0028] Formed on the rear housing 5 are a suction chamber 11 and a
discharge chamber 13, which are communicated to the respective
cylinder bores 1a through a valve unit 9. Also, the front housing 3
and the cylinder block 1 define a crank chamber 15 and axial holes
3a, 1b are formed on the front housing 3 and the cylinder block 1.
A shaft seal device 17 is provided in the axial hole 3a. A rubber
material is used for the shaft seal device 17. Also, a plain
bearing 19 is provided in the axial hole 1b. A receiving chamber 1c
communicated to the axial hole 1b is formed centrally of a rear end
of the cylinder block 1, the receiving chamber 1c is opposed to the
valve unit 9.
[0029] The drive shaft 7 is supported to be able to rotate by the
shaft seal device 17, etc. in a state, in which one end thereof is
exposed from the front housing 3 and a central portion thereof
faces into the crank chamber 15. A pulley and an electromagnetic
clutch, both of which are not shown, are connected to the drive
shaft 7, and the drive shaft 7 is rotationally driven by a drive
source, such as an engine, etc. through a belt stretched round the
pulley and the electromagnetic clutch. Also, pistons 21,
respectively, are received in the respective cylinder bores 1a to
be able to reciprocate, the respective pistons 21, respectively,
defining compression chambers in the cylinder bores 1a.
[0030] A lug plate 23 receiving compressive reaction force is fixed
to the drive shaft 7 in the crank chamber 15, and a thrust bearing
25 and a plain bearing 27 are provided between the lug plate 23 and
the front housing 3. Also, the drive shaft 7 is inserted through a
swash plate 29, of which inclination to an imaginary plane
perpendicular to the drive shaft 7 is variable. A hinge portion 23a
is formed on the lug plate 23 to be directed toward the swash plate
29, a hinge portion 29a is provided on the swash plate 29 to be
directed toward the lug plate 23, and the hinge portions 23a, 29a
constitute a linkage 31. Also, a push spring 33 is provided between
the lug plate 23 and the swash plate 29 to bias the both in a
direction, in which the both separate from each other.
[0031] Also, pairs of front and rear shoes 35 are provided between
the swash plate 29 and the respective pistons 21. The shoe 35 on a
front side is provided between a front surface of the swash plate
29 and a front seat surface of the piston 21, and the shoe 35 on a
rear side is provided between a rear surface of the swash plate 29
and a rear seat surface of the piston 21. The respective shoes 35
are substantially semi-spherical in shape. The respective shoes 35
serve as a motion conversion mechanism.
[0032] Formed on the drive shaft 7 are a first hole 37 extending in
a radial direction, an outflow hole 39 communicated to the first
hole 37 to extend coaxially with an axis in an axial direction to
extend to a rear end of the drive shaft 7, and a valve hole 41
communicated to the outflow hole 39 to extend in a radial
direction.
[0033] As shown in FIG. 2, the first hole 37 is disposed between
the lug plate 23 and the front housing 3 and formed over an extent
of a radius of the drive shaft 7 from an axis of the drive shaft 7
to an outer periphery thereof. An oil guide groove 3b is formed on
the front housing 3 to extend between the front housing 3 and the
lug plate 23 from an outer peripheral region of the crank chamber
15 to face the thrust bearing 25. Also, an oil guide hole 3c is
formed on the front housing 3 to be communicated to the oil guide
groove 3b to face the plain bearing 27 and the shaft seal device
17. The oil guide hole 3c faces the shaft seal device 17 in the
axial hole 3a to be communicated to the first hole 37. The oil
guide groove 3b and the oil guide hole 3c serve as an oil guide
path.
[0034] As shown in FIG. 1, the rear end of the drive shaft 7
projects into the receiving chamber 1c and a rear end of the
outflow hole 39 is closed by a plug member 43. The valve hole is
formed a little ahead of the plug member 43. As shown in FIGS. 3
and 4, the valve hole 41 is provided through the drive shaft 7 to
communicate the outflow hole 39 to the receiving chamber 1c.
[0035] A valve mechanism 45 is provided round the valve hole 41.
The valve mechanism 45 includes a spherical-shape valve body 47
that can be seated on one opening 41a of the valve hole 41, and a
case 49 fixed to the drive shaft 7 around the valve hole 41. The
valve body 47 serves also as a mass body. The case 49 includes a
valve chamber 49a on a side toward the opening 41a. Provided in the
valve chamber 49a are a first spring 51 that biases the valve body
47 in a direction away from the opening 41a, and a second spring 53
having a bias that biases the valve body 47 in a direction toward
the opening 41a. The valve chamber 49a is communicated to the
receiving chamber 1c through a communication port 49b formed on the
case 49.
[0036] As shown in FIG. 1, a throttle hole 9a for communication of
the receiving chamber 1c with the suction chamber 11 is provided on
the valve unit 9 to extend therethrough. Also, a second hole 55 is
formed on the cylinder block 1 and the valve unit 9 to provide
communication between the suction chamber 11 and an inner
peripheral region of the crank chamber 15, that is, a region close
to the drive shaft 7. A throttle 55a is formed on the second hole
55 in the valve unit 9. The oil guide groove 3b, the oil guide hole
3c, the first hole 37, the outflow hole 39, the valve hole 41, the
communication port 49b, the receiving chamber 1c, the throttle hole
9a, and the second hole 55 constitute a release passage. The oil
guide groove 3b, the oil guide hole 3c, the first hole 37, the
outflow hole 39, the valve hole 41, the communication port 49b, the
receiving chamber 1c, and the throttle hole 9a constitute a first
passage. Also, the second hole 55 constitutes a second passage. In
addition, the communication port 49b and the throttle hole 9a are
set to be equal to or larger in opened cross sectional area than
the opening 41a of the valve hole 41.
[0037] Also, a capacity control valve 57 is received in the rear
housing 5. The capacity control valve 57 is communicated to the
suction chamber 11 through a detection passage 59 and provides
communication between the discharge chamber 13 and the crank
chamber 15 through the detection passage 59. The capacity control
valve 57 detects pressure in the suction chamber 11 to change
opening degree of a supply passage 61 to change the discharge
capacity of a compressor.
[0038] A pipe 63 is connected to the discharge chamber 13, the pipe
63 being connected to the suction chamber 11 through a check valve
65, a condenser 67, an expansion valve 69, and an evaporator 71.
The compressor, the check valve 65, the condenser 67, the expansion
valve 69, the evaporator 71, and the pipe 63 constitute a
refrigerating circuit. Refrigerating gas mixed with lubricating oil
is charged in the refrigerating circuit.
[0039] With the compressor thus constructed, the capacity control
valve 57 adjusts pressure in the crank chamber 15 on the basis of
pressure in the suction chamber 11 and a flow rate of refrigerating
gas to change an angle of the swash plate 29 to the drive shaft 7
to change a discharge capacity thereof.
[0040] Also, with the compressor, when the drive shaft 7 is rotated
at high speed while a vehicle is running at high speed, the valve
body 47 of the valve mechanism 45 is caused by large centrifugal
force and the bias of the first spring 51 to move away from the
axis of the drive shaft 7 against the bias of the second spring 53,
whereby the valve body 47 increases opening degree of the opening
41a as shown in FIG. 4.
[0041] Therefore, opening degree, at which the valve hole 41 is
communicated to the communication port 49b, increases and opening
degree, at which the first hole 37 shown in FIG. 2 is communicated
to the communication port 49b, increases. At this time, the second
hole 55 provides communication in a predetermined cross sectional
area between the crank chamber 15 and the suction chamber 11.
Therefore, as shown in FIG. 5, a throttle area, in which the crank
chamber 15 and the suction chamber 11 are communicated to each
other, becomes large. That is, the single valve mechanism 45
increases a ratio, at which the first hole 37 occupies the release
passage, and decreases a ratio, at which the second hole 55
occupies the release passage.
[0042] In an outer peripheral region of the crank chamber 15 shown
in FIG. 2, the lubricating oil is present in abundance and the
lubricating oil is led to the first hole 37 through the oil guide
groove 3b and the oil guide hole 3c. At this time, the lubricating
oil is led to the first hole 37 through the shaft seal device 17,
so that a large quantity of the lubricating oil is supplied to the
shaft seal device 17 to heighten the shaft seal device 17 in
durability.
[0043] Owing to the first hole 37 increased in that ratio, at which
it occupies the release passage, refrigerating gas disposed in the
crank chamber 15 and containing a large quantity of the lubricating
oil is led to the receiving chamber 1c through the outflow hole 39,
the valve hole 41, and the communication port 49b and further moved
to the suction chamber via the throttle hole 9a. Therefore, the
lubricating oil in the crank chamber 15 becomes moderate in
quantity and so the swash plate 29 does not agitate the lubricating
oil so much, so that the lubricating oil is hard to generate heat
due to shearing and hard to decrease in viscosity. Therefore,
sliding portions between the swash plate 29 and the respective
shoes 35 are favorably lubricated. Also, refrigerating gas sucked
from the suction chamber 11 contains a large quantity of the
lubricating oil and sliding portions between the cylinder bores 1a
and the pistons 21 are favorably lubricated. Thereby, an excellent
durability exhibits itself at high speed.
[0044] In addition, while the lubricating oil contained in
refrigerating gas discharged to the refrigerating circuit outside
the compressor are increased in quantity at this time, no problem
is caused in refrigerating capacity since the pistons 21
reciprocate at high speed.
[0045] Also, when the drive shaft 7 is rotated at low speed while a
vehicle is running at low speed, the valve body 47 of the valve
mechanism 45 resists the bias of the first spring 51 because of
small centrifugal force and yields to the bias of the second spring
53 to approach the axis of the drive shaft 7 as shown in FIG. 3,
and thus the valve body 47 decreases opening degree of the opening
41a. When the drive shaft 7 is rotated at a further low speed, the
valve body 47 is seated on the opening 41a to close the valve hole
41.
[0046] Therefore, opening degree, at which the valve hole 41 is
communicated to the communication port 49b, decreases and opening
degree, at which the first hole 37 shown in FIG. 2 is communicated
to the communication port 49b, decreases. Also, at this time, the
second hole 55 provides communication in a predetermined cross
sectional area between the crank chamber 15 and the suction chamber
11. Therefore, as shown in FIG. 5, a throttle area, in which the
crank chamber 15 and the suction chamber 11 are communicated to
each other, becomes small. That is, the single valve mechanism 45
decreases a ratio, at which the first hole 37 occupies the release
passage, and increases a ratio, at which the second hole 55
occupies the release passage.
[0047] The lubricating oil is small in quantity in an inner
peripheral region of the crank chamber 15 shown in FIG. 2, that is,
a region close to the drive shaft 7, and refrigerating gas not
containing much of the lubricating oil is led into the second hole
55 from there.
[0048] Owing to the second hole 55 increased in that ratio, at
which it occupies the release passage, refrigerating gas not
containing much of the lubricating oil within the crank chamber 15
is moved to the suction chamber 11 via the throttle 55a. Therefore,
the lubricating oil contained in refrigerating gas discharged to
the refrigerating circuit outside the compressor is decreased in
quantity, so that a high refrigerating capacity exhibits
itself.
[0049] Further, with the swash plate compressor, the first hole 37
is closed when the drive shaft 7 is rotated at low speed.
Accordingly, the sum of the cross sectional area of the opening of
the release passage decreases whereby refrigerating gas moving to
the suction chamber 11 from the crank chamber 15 is decreased in
quantity, and refrigerating gas circulated within the swash plate
compressor is decreased in quantity whereby refrigerating gas used
for the proper object is increased in quantity and the swash plate
compressor is improved in performance.
[0050] In addition, while the lubricating oil in the crank chamber
15 is increased in quantity, the swash plate 29 only agitates the
lubricating oil at low speed, so that the lubricating oil is little
raised in temperature and the lubricating oil is not decreased so
much in viscosity. Therefore, sliding portions are still lubricated
favorably.
[0051] Accordingly, the compressor can demonstrate an excellent
sliding characteristic when the drive shaft 7 is rotated at high
speed, and can demonstrate a high refrigerating capacity when the
drive shaft 7 is rotated at low speed.
Embodiment 2
[0052] With a swash plate compressor according to EMBODIMENT 2, a
plurality of cylinder bores 2a extending in parallel to an axis of
a drive shaft 8 are provided on a cylinder block 2 to extend
therethrough as shown in FIG. 6. Formed on a rear housing 6 are a
suction chamber 12 and a discharge chamber 14, which are
communicated to the respective cylinder bores 2a through a valve
unit 10. Also, a front housing 4 and the cylinder block 2 define a
crank chamber 16 and axial holes 4a, 2b are formed on the front
housing 4 and the cylinder block 2. A shaft seal device 18 and a
plain bearing 20 are provided in the axial hole 4a. A rubber
material is used for the shaft seal device 18. Also, a plain
bearing 22 is provided in the axial hole 2b. A receiving chamber 2c
communicated to the axial hole 2b is formed centrally of a rear end
of the cylinder block 2, the receiving chamber 2c being opposed to
the valve unit 10.
[0053] The drive shaft 8 is supported by the shaft seal device 18,
etc. in a state to be able to rotate, in which one end thereof is
exposed from the front housing 4 and a central portion thereof
faces the crank chamber 16. Also, pistons 24, respectively, are
received in the respective cylinder bores 2a to be able to
reciprocate, the respective pistons 24 defining compression
chambers in the cylinder bores 2a.
[0054] A lug plate 26 receiving compressive reaction force is fixed
to the drive shaft 8 in the crank chamber 16, and a thrust bearing
28 is provided between the lug plate 26 and the front housing 4.
Also, the drive shaft 8 is inserted through a swash plate 30 to
make the same variable in inclination angle. A linkage 32 is formed
between the lug plate 26 and the swash plate 30. Also, push springs
34, 36 are provided between the lug plate 26 and the swash plate 30
and between the swash plate and the drive shaft 8. Also, pairs of
front and rear shoes are provided between the swash plate 30 and
the respective pistons 24.
[0055] The drive shaft 8 comprises a body 8a, of which a rear end
is formed to be cylindrical-shaped, and a tubular body 8b in the
form of a cylinder inserted from the rear end of the body 8a to be
fixed in the body 8a. A first hole 40 being annular and extending
in an axial direction is defined between the body 8a and the
tubular body 8b. A guide hole 26a formed midway thereof with a step
is formed on the lug plate 26 to be perpendicular to an axis. The
guide hole 26a is communicated at an inner end thereof to the first
hole 40 and communicated at an outer end thereof to an outer
peripheral region of the crank chamber 16. A valve chamber 26b is
defined midway the guide hole 26a in the lug plate 26 and a valve
mechanism 42 is provided in the valve chamber 26b. The valve
mechanism 42 comprises a valve body 42a that can be seated on an
opening of the guide hole 26a on an inner end side, and a spring
42b that biases the valve body 42a in a direction of seating. The
valve body 42a serves as a mass body. A cylindrical-shaped cover
body 26c is press fitted into the guide hole 26a outside the valve
chamber 26b to support one end of the spring 42b.
[0056] Formed on the body 8a of the drive shaft 8 are a second hole
44 extending radially, and a communication hole 46 communicated to
the second hole 44 to extend coaxially with an axis in an axial
direction. Formed on the tubular body 8b is an outflow hole 48
communicated to the communication hole 46 to extend to a rear end
of the drive shaft 8. The second hole 44 is disposed between the
shaft seal device 18 and the plain bearing 20 to be formed over an
extent of a radius of the drive shaft 8 from an axis of the drive
shaft 8 to an outer periphery thereof. An oil guide hole 4b is
formed on the front housing 4 to open to an inner peripheral region
of the crank chamber 16 between the front housing 4 and the lug
plate 26. The oil guide hole 4b faces the shaft seal device 18 in
the axial hole 4a to be communicated to the second hole 44. The
rear end of the drive shaft 8 projects into the receiving chamber
2c.
[0057] A throttle hole 10a for communication of the receiving
chamber 2c with the suction chamber 12 is provided on the valve
unit 10 to extend therethrough. The guide hole 26a, the valve
chamber 26b, the first hole 40, the oil guide hole 4b, the second
hole 44, the communication hole 46, the outflow hole 48, the
receiving chamber 2c, and the throttle hole 10a constitute a
release passage. The guide hole 26a, the valve chamber 26b, the
first hole 40, the receiving chamber 2c, and the throttle hole 10a
constitute a first passage. Also, the oil guide hole 4b, the second
hole 44, the communication hole 46, the outflow hole 48, the
receiving chamber 2c, and the throttle hole 10a constitute a second
passage. The remaining construction is the same as that of
EMBODIMENT 1.
[0058] With the compressor, when the drive shaft 8 is rotated at
high speed while a vehicle is running at high speed, or the like,
the valve body 42a of the valve mechanism 42 is caused by large
centrifugal force to get away from the axis of the drive shaft 8
against the bias of the spring 42b, whereby the valve body 42a
increases opening degree of the guide hole 26a. At this time, the
second hole 44 provides communication in a predetermined cross
sectional area between the crank chamber 16 and the suction chamber
12. Therefore, a throttle area, in which the crank chamber 16 and
the suction chamber 12 are communicated to each other, becomes
large. Therefore, the single valve mechanism 42 is increased a
ratio, at which the first hole 40 occupies the release passage, and
decreased a ratio, at which the second hole 44 occupies the release
passage.
[0059] Also, when the drive shaft 8 is rotated at low speed while a
vehicle is running at low speed, or the like, the valve body 42a of
the valve mechanism 42 is caused by the bias of the spring 42b to
approach the axis of the drive shaft 8 against small centrifugal
force, and thus the valve body 42a decreases opening degree of the
guide hole 26a. When the drive shaft 8 is rotated at a further low
speed, the valve body 42a is seated on the guide hole 26a. At this
time, the second hole 44 provides communication in a predetermined
cross sectional area between the crank chamber 16 and the suction
chamber 12. Therefore, a throttle area, in which the crank chamber
16 and the suction chamber 12 are communicated to each other,
becomes small. Therefore, the single valve mechanism 42 is
decreased a ratio, at which the first hole 40 occupies the release
passage, and increased a ratio, at which the second hole 44
occupies the release passage.
[0060] Accordingly, with the compressor, the same function and
effect as those of EMBODIMENT 1 can be produced. With the
compressor, since the oil guide hole 4b is communicated to an inner
peripheral region of the crank chamber 16 and only a small quantity
of the lubricating oil is supplied to the oil guide hole 4b when
the compressor is rotated at high speed, the compressor of
EMBODIMENT 1 is excellent in terms of durability of the rubber
material for the shaft seal device 18 when the compressor is
rotated at high speed. However, the lubricating oil can be supplied
to the shaft seal device 18 at all times.
[0061] While the invention has been described with respect to
EMBODIMENT 1 and EMBODIMENT 2, it goes without saying that the
invention is not limited to EMBODIMENT 1 and EMBODIMENT 2 but can
be appropriately changed within a scope not departing from the gist
thereof and applied.
[0062] For example, as shown in FIG. 7, it is possible in the
compressor of EMBODIMENT 1 to remove the throttle 55 as a second
passage and to form on the drive shaft 7 a throttle 55b, which
provides communication between the outflow hole 39 and the
receiving chamber 1c and is the same in diameter as the throttle
55a, as a second passage.
[0063] With such construction, a second passage is easy to form;
the lubricating oil can be supplied to the shaft seal device 18 at
all times, and the same effect as that of EMBODIMENT 2 can be
produced. In addition, in this case, the throttle hole 9b is set to
be equal to or larger in opened cross sectional area than the sun
of the opened cross sectional areas of the opening 41a of the valve
hole 41 and the throttle 55b.
[0064] Also, as shown in FIG. 8, it is possible to remove the
throttle 55 as a second passage and to provide a groove 55c, which
bypasses the valve body 47, as a second passage on the opening 41a
of the valve hole 41. With such construction, the same effect can
be produced.
[0065] Also, with the compressor of EMBODIMENT 2, it is preferred
that an opening of the guide hole 26a on an outer end side thereof
be forward in a direction of rotation of the lug plate 26 to
facilitate taking the lubricating oil in the crank chamber 16 into
the guide hole 26a.
[0066] Also, in the case where radial bearings using rollers are
adopted in place of the plain bearings 19, 22 in the compressors of
EMBODIMENT 1 and EMBODIMENT 2, a release passage may be provided
between the respective rollers and ratios, at which the first
passage and the second passage occupy the release passage, may be
changed. Also, the linkages 31, 32 are not limited to those in the
embodiments but various arrangements may be adopted.
[0067] The swash plate compressor of the invention may be of a
fixed displacement type, in which a swash plate is invariable in
inclination angle, or may be of a variable displacement type, in
which a swash plate is variable in inclination angle.
[0068] Also, with the swash plate compressor of the invention, the
release passage may be enough to communicate the crank chamber to
the suction chamber, may be one for direct communication of the
crank chamber to the suction chamber, or may be one for indirect
communication of the crank chamber to the suction chamber through a
suction passage, etc. communicated to the suction chamber. The
release passage suffices to include the first passage, or may
include another passage.
[0069] The first passage is communicated to any one of those
regions, in which lubricating oil is present in abundance. Regions,
in which the lubricating oil is present in abundance, are
determined by intercomparison with other regions.
[0070] The release passage can include a second passage
communicated to that region, in which lubricating oil is small in
quantity in the crank chamber. The valve mechanism can increase a
ratio, at which the first passage occupies the release passage, as
the drive shaft is increased in rotating speed, and can decrease a
ratio, at which the second passage occupies the release passage, as
the drive shaft is decreased in rotating speed.
[0071] In this case, the release passage comprises the first
passage and the second passage and refrigerating gas not containing
much of the lubricating oil in the crank chamber can be moved to
the suction chamber by the second passage. Therefore, the valve
mechanism is liable to change a ratio, at which the first passage
occupies the release passage, so that an improvement in
responsibility relative to the rotating speed is achieved.
[0072] Also, with the swash plate compressor, when the drive shaft
is rotated at low speed, the valve mechanism decreases a ratio, at
which the first passage occupies the release passage. Therefore,
refrigerating gas containing a large quantity of lubricating oil in
the crank chamber is not moved so much to the suction chamber by
the first passage decreased in that ratio, at which it occupies the
release passage, but refrigerating gas not containing much of the
lubricating oil in the crank chamber is moved to the suction
chamber by the second passage. Therefore, the lubricating oil
contained in refrigerating gas discharged to a refrigerating
circuit outside the swash plate compressor are decreased in
quantity, so that a high refrigerating capacity is
demonstrated.
[0073] Further, with the swash plate compressor, when the drive
shaft is rotated at low speed, the sum of the cross sectional area
of the opening of the release passage decreases whereby
refrigerating gas moving to the suction chamber from the crank
chamber is decreased in outflow and refrigerating gas circulated
within the compressor is decreased in quantity, so that
refrigerating gas used for the proper object is increased in
quantity and the compressor is improved in performance. In
particular, with a clutchless type swash plate compressor, in which
power is transmitted to a drive shaft of the swash plate compressor
at all times in operation of a drive source, refrigerating gas is
only circulated within the compressor when cooling is not needed,
but refrigerating gas as circulated can be made minimum when the
drive shaft is rotated at low speed, so that it is possible to
realize demonstration of an excellent sliding characteristic when
the drive shaft is rotated at high speed, and reduction in power
for the compressor when the drive shaft is rotated at low
speed.
[0074] The second passage is preferably formed with a throttle.
[0075] In this case, refrigerating gas not containing much of the
lubricating oil in the crank chamber is made difficult to move to
the suction chamber, so that the effect of the invention produced
by the lubricating oil becomes conspicuous.
[0076] With the swash plate compressor of the invention, the swash
plate can be supported to be variable in inclination angle. Also, a
lug plate receiving compressive reaction force can be fixed to the
drive shaft to be able to rotate integrally. Further, an oil guide
path can be formed on the housing to extend between the housing and
the lug plate from an outer peripheral region of the crank chamber.
The first passage is preferably communicated to the oil guide
path.
[0077] According to experiments conducted by the inventors of the
present invention, an outer peripheral region of a crank chamber in
a swash plate compressor is a region, in which lubricating oil is
present in abundance, so that it is possible to readily lead the
lubricating oil to a first passage via the oil guide path.
[0078] A shaft seal device can be provided between the housing and
the drive shaft to seal the drive shaft exposed from the housing.
The first passage is preferably communicated to the oil guide path
via the shaft seal device.
[0079] In this case, by supplying a large quantity of lubricating
oil to the shaft seal device, it is possible to improve durability
of a rubber material for the shaft seal device.
[0080] With the swash plate compressor of the invention, the swash
plate can be supported to be variable in inclination angle. Also, a
lug plate receiving compressive reaction force can be fixed to the
drive shaft to be able to rotate integrally. Further, the first
passage can include a guide hole formed on the lug plate and opened
to an outer peripheral region of the crank chamber.
[0081] According to results of tests made by inventors of the
present application, an outer peripheral region of a crank chamber
in a swash plate compressor is a region, in which lubricating oil
is present in abundance, so that it is possible to readily lead the
lubricating oil to a first passage via the oil guide hole.
[0082] With the swash plate compressor of the invention, a shaft
seal device can be provided between the housing and the drive shaft
to seal the drive shaft exposed from the housing. Also, the second
passage is preferably opened to the crank chamber in the vicinity
of the shaft seal device.
[0083] In this case, lubricating oil can be supplied to the shaft
seal device at all times, so that the shaft seal device can be
improved in durability.
EXPLANATION OF INDUSTRIAL APPLICATION OF INVENTION
[0084] The invention can be made use of in air-conditioning
apparatuses for vehicles.
* * * * *