U.S. patent application number 09/878595 was filed with the patent office on 2001-12-20 for piston type variable displacement compressor.
Invention is credited to Fujii, Toshiro, Koide, Tatsuya, Suzuki, Junya, Yagi, Kiyoshi, Yokomachi, Naoya.
Application Number | 20010053327 09/878595 |
Document ID | / |
Family ID | 18679831 |
Filed Date | 2001-12-20 |
United States Patent
Application |
20010053327 |
Kind Code |
A1 |
Yokomachi, Naoya ; et
al. |
December 20, 2001 |
Piston type variable displacement compressor
Abstract
In the piston type variable displacement compressor of the
present invention, in the crank chamber 5 in which the crank
mechanism is arranged, the outlet 28A of the gas supply passage 28,
for supplying refrigerant from the discharge chamber 22, is open at
an upper position of the crank mechanism in the peripheral wall
section of the housing. The control valve 29 is arranged in the
middle of the gas supply passage 28, so that a flow rate of the
refrigerant supplied into the crank chamber 5 via the gas supply
passage 28 can be adjusted. Mist-like lubricant is mixed with the
refrigerant. Therefore, even when the flow rate of the refrigerant
is low, the crank chamber 5 can be excellently lubricated.
Inventors: |
Yokomachi, Naoya;
(Kariya-shi, JP) ; Yagi, Kiyoshi; (Kariya-shi,
JP) ; Koide, Tatsuya; (Kariya-shi, JP) ;
Suzuki, Junya; (Kariya-shi, JP) ; Fujii, Toshiro;
(Kariya-shi, JP) |
Correspondence
Address: |
Woodcock Washburn Kurtz
Mackiewicz & Norris LLP
One Liberty Place, 46th Floor
Philadelphia
PA
19103
US
|
Family ID: |
18679831 |
Appl. No.: |
09/878595 |
Filed: |
June 11, 2001 |
Current U.S.
Class: |
417/222.2 |
Current CPC
Class: |
F04B 27/109
20130101 |
Class at
Publication: |
417/222.2 |
International
Class: |
F04B 001/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 14, 2000 |
JP |
2000-178397 |
Claims
1. A piston type variable displacement compressor comprising: a
crank chamber defined in a housing; and a crank mechanism, arranged
in the crank chamber, for transforming a rotational motion of a
drive shaft into a reciprocating motion of a piston which sucks,
compresses and discharges refrigerant and also for changing a
stroke of the piston according to inner pressure in the crank
chamber, wherein an outlet of a gas supply passage for supplying
the refrigerant from a high pressure region into the crank chamber
is open at an upper position of the crank mechanism in the crank
chamber.
2. A piston type variable displacement compressor according to
claim 1, wherein a control valve for controlling a quantity of the
refrigerant supplied from the gas supply passage into the crank
chamber is arranged in the gas supply passage.
3. A piston type variable displacement compressor according to
claim 1, wherein the piston type variable displacement compressor
is of the type in which a swash plate and the drive shaft are
integrated and rotated with each other.
4. A piston type variable displacement compressor according to
claim 1, wherein the piston type variable displacement compressor
is of the type in which a swash plate and the drive shaft are
rotated, but not integrated, with each other.
5. A piston type variable displacement compressor according to
claim 1, wherein the outlet is formed toward a thrust bearing for
supporting the crank mechanism in the direction of the drive shaft
and/or a hinge mechanism for changing the stroke of the piston.
6. A piston type variable displacement compressor according to
claim 1, wherein a gas extraction passage for introducing the
refrigerant from the crank chamber into a low pressure region is
provided, and a control valve for controlling a quantity of the
refrigerant introduced from the crank chamber into the low pressure
region is arranged in the gas extraction passage.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a piston type variable
displacement compressor. For example, the present invention relates
to a piston type variable displacement compressor having a
characteristic lubrication structure in its crank chamber.
[0003] 2. Description of the Related Art
[0004] In general, a piston type variable displacement compressor
includes: a drive shaft rotated by an external drive source; and a
piston for sucking, compressing and discharging refrigerant
according to a rotational motion of the drive shaft. A rotational
motion of the drive shaft is transformed into a reciprocating
motion of the piston by a crank mechanism provided in a crank
chamber. This crank mechanism functions as a variable displacement
mechanism for changing a stroke of the piston according to the
inner pressure in the crank chamber. This crank mechanism is
composed of a plurality of parts, and a large number of sliding
sections, in which the parts slide on each other, are arranged in
the crank mechanism. In order to operate the crank mechanism
smoothly, it is necessary to ensure a smooth sliding motion in each
sliding section. In order to ensure the smooth sliding motion,
there is commonly used a structure in which lubricant is made into
mist and this mist of lubricant is mixed in the refrigerant gas
flowing in the compressor, so that the compressor can be lubricated
by this mist of lubricant. An example of this structure is
disclosed in Japanese Unexamined Patent Publication No. 10-299647,
which will be described as follows. In a cylinder block arranged
between a crank chamber and a region, the pressure of which is
higher than that in the crank chamber, such as, for example, in a
cylinder block arranged between a crank chamber and a discharge
chamber, the pressure of which is higher than that in the crank
chamber, there is provided a communicating passage for
communicating the crank chamber with the high pressure region.
Further, there is provided a lubricant sucking passage for
connecting this communicating passage with an oil reservoir section
in the crank chamber. The lubricant is sucked up by the pressure of
the refrigerant gas, which passes through this communicating
passage from the high pressure region to the crank chamber, from
the oil reservoir section via the lubricant sucking passage. The
thus sucked lubricant is atomized in the crank chamber. In this
structure, there is provided a hinge mechanism for changing an
inclination angle of a swash plate. This hinge mechanism is
arranged on the opposite side to the cylinder block with respect to
the swash plate. In this structure, the lubricant is atomized on
the cylinder block side of the swash plate.
[0005] However, the above structure disclosed in the above
unexamined patent publication has the following disadvantages.
Since the communicating passage is formed in the cylinder block, it
must be formed between the cylinder bores which are composed in the
cylinder block. In this structure, the hinge mechanism is arranged
on the opposite side to the cylinder block with respect to the
swash plate. Therefore, it is difficult for the lubricant, which
has been atomized in the communicating passage, to reach the hinge
mechanism. Further, in this structure, an outlet for the
refrigerant gas in the communicating passage is arranged at a
position lower than the drive shaft. Therefore, it is very
difficult to spread the lubricant all over the crank chamber.
Especially when a flow rate of the refrigerant gas passing in the
communicating passage is low, the above disadvantages become
remarkable.
SUMMARY OF THE INVENTION
[0006] It is an object of the present invention to provide a piston
type variable displacement compressor having a simple structure by
which a piston chamber can be excellently lubricated in any
operating condition.
[0007] In order to solve the above problems, the present invention
provides a piston type variable displacement compressor comprising:
a crank chamber defined in a housing; and a crank mechanism,
arranged in the crank chamber, for transforming a rotational motion
of a drive shaft into a reciprocating motion of a piston which
sucks, compresses and discharges refrigerant and also for changing
a stroke of the piston according to an inner pressure in the crank
chamber, wherein an outlet of a gas supply passage for supplying
the refrigerant from a high pressure region into the crank chamber
is open at an upper position of the crank mechanism in the crank
chamber.
[0008] Due to the above structure, the degree of freedom in
designing the arrangement of the outlet can be increased as
compared with an arrangement in which the outlet is open to the
cylinder block. Therefore, the above structure is very effective in
the case where parts, which require complete lubrication, such as
parts receiving high intensity compressive reaction forces from the
piston, are arranged separate from the cylinder block. When the
above outlet is open at an upper position of the crank mechanism,
the mist-like lubricant mixed in the refrigerant easily spreads all
over the crank chamber, so that the crank chamber can be
excellently lubricated, especially, the crank mechanism can be
effectively lubricated. For example, even when a flow rate of the
refrigerant supplied into the crank chamber via the gas supply
passage is low, a relatively large quantity of the lubricant can be
supplied to the crank mechanism because the lubricant is supplied
from an upper portion of the crank mechanism. Since the above
effects can be provided by a simple structure in which the outlet
is arranged in the housing on the crank chamber side, it is
possible to expect a reduction in the manufacturing cost.
[0009] In this connection, in the present invention, the upper
portion of the crank mechanism is defined as a region on the upper
side of the horizontal face passing through the drive shaft except
for the crank mechanism.
[0010] The present invention will be more fully understood with
reference to the accompanying drawings and the preferred
embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
[0011] In the drawing:
[0012] FIG. 1 is a cross-sectional view showing an outline of a
piston type variable displacement compressor of an embodiment of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] Referring to FIG. 1, an embodiment of the present invention
will be explained below. In this embodiment, the upper side of FIG.
1 is defined as upper, and the left of FIG. 1 is defined as
front.
[0014] As shown in FIG. 1, a compressor C includes: a cylinder
block 1; a front housing 2 joined to the front end of the cylinder
block 1; and a rear housing 4 joined to the rear end of the
cylinder block 1 via a valve forming body 3. These cylinder block
1, front housing 2, valve forming body 3 and rear housing 4 are
joined and fixed to each other by a plurality of through-bolts 10
(Only one through-bolt 10 is shown in FIG. 1.), so that the housing
of compressor C is completed. In a region surrounded by the
cylinder block 1 and the front housing 2, there is defined a crank
chamber 5. In the crank chamber 5, the drive shaft 6 is rotatably
supported by a pair of radial bearings 8A, 8B which are
respectively arranged in the front and the rear portion of the
drive shaft 6. In an accommodation recess formed at the center of
the cylinder block 1, there are provided a spring 7 and a rear
thrust bearing 9B. On the other hand, the lug plate 11 is fixed to
the drive shaft 6 in the crank chamber 5 in such a manner that the
lug plate 11 can be rotated integrally with the drive shaft 6. The
front side thrust bearing 9A is arranged between the lug plate 11
and the inner wall face of the front housing 2. The drive shaft 6
and the lug plate 11, which are integrated with each other, are
positioned in the direction of thrust (the axial direction of the
drive shaft) by the rear thrust bearing 9B, which is pushed to the
front side by a spring 7, and the front thrust bearing 9A.
[0015] The front end portion of the drive shaft 6 is connected with
a vehicle engine E, which is an external drive source, via a power
transmission PT. The power transmission PT may be a clutch
mechanism (for example, an electromagnetic clutch) by which power
can be transmitted and/or shut off by electrically controlling the
clutch mechanism from outside. Alternatively, the power
transmission PT may be a clutchless mechanism (for example, a
combination of a belt with a pulley) having no clutch mechanism, by
which power can be transmitted at all times. In this connection, in
this embodiment, the clutchless type power transmission mechanism
is adopted.
[0016] As shown in FIG. 1, in the crank chamber 5, there is
provided a swash plate 12 which is a cam plate. A through-hole is
formed at the center of the swash plate 12. The drive shaft 6 is
arranged penetrating this through-hole formed at the center of the
swash plate 12. The swash plate 12 is connected with the lug plate
11 and the drive shaft 6 via the hinge mechanism 13. The hinge
mechanism 13 includes: two support arms 14 (Only one support arm is
shown in the drawing.) protruding from the rear face of the lug
plate 11; and two guide pins 15 (Only one guide pin is shown in the
drawing.) protruding from the front face of the swash plate 12.
Since the support arms 14 are connected with the guide pins 15 and
the drive shaft 6 comes into contact with the central insertion
hole of the swash plate 12, the swash plate 12 can be
simultaneously rotated with the lug plate 11 and the drive shaft 6,
and further the swash plate 12 can be tilted with respect to the
drive shaft 6 while the swash plate 12 is being slid in the axial
direction of the drive shaft 6.
[0017] Between the lug plate 11 and the swash plate 12, there is
provided an inclination angle reducing spring 16 which is arranged
round the drive shaft 6. This inclination angle reducing spring 16
pushes the swash plate 12 in a direction so that the swash plate 12
can approach the cylinder block 1, that is, the inclination angle
can be reduced. Between a restriction ring 18, which is fixed to
the drive shaft 6, and the swash plate 12, there is provided a
return spring 17 which is arranged around the drive shaft 6. When
the swash plate 12 is tilted by a large angle as shown by a
two-dotted chain line, this return spring 17 is only wound round
the drive shaft 6 and has no influence on the swash plate and other
members. However, when the swash plate 12 is tilted by a small
angle as shown by a solid line, this return spring 17 is compressed
between the restriction ring 18 and the swash plate 12, and the
swash plate 12 is pushed in a direction so that the swash plate 12
can be separated from the cylinder block 1, that is, the
inclination angle can be increased. In this connection, in this
embodiment, the inclination angle of the swash plate 12 is defined
as an angle formed between a virtual plane, which is perpendicular
to the drive shaft 6, and the swash plate 12.
[0018] In the cylinder block 1, there are provided a plurality of
cylinder bores 1a (Only one cylinder bore is shown in the drawing.)
which are arranged round the drive shaft 6. An end on the rear side
of each cylinder bore 1a is closed by the valve forming body 3. In
each cylinder bore 1a, there is provided a single-headed type
piston 20 capable of reciprocating. In each cylinder bore 1a, there
is provided a compression chamber, the volume of which is changed
according to the reciprocating motion of the piston 20. The front
end portion of each piston 20 is engaged with the outer peripheral
portion of the swash plate 12 via a pair of shoes 19. Each piston
20 is connected with the swash plate 12 via these shoes 19. Due to
the above structure, when the swash plate 12 is simultaneously
rotated with the drive shaft 6, the rotational motion of the swash
plate 12 is converted into the reciprocating linear motion of the
piston 20, the stroke of which corresponds to the inclination angle
of the swash plate 12.
[0019] In this connection, a crank mechanism is composed in which
the front side thrust bearing 9A, lug plate 11, swash plate 12,
support arm 14, guide pin 15 and shoes 19 convert the rotational
motion of the drive shaft 6 into the reciprocating motion of the
piston 20 and at the same time the stroke of the piston 20 is
changed.
[0020] Between the valve forming body 3 and the rear housing 4,
there are provided a suction chamber 21 which is a low pressure
region located at the central region, and a discharge chamber 22
which is a high pressure region surrounding the suction chamber 21.
The valve forming body 3 is composed of a suction valve forming
plate, port forming plate, discharge valve forming plate and
retainer forming plate which are put on each other. In this valve
forming body 3, corresponding to each cylinder bore 1a, there are
provided a suction port 23, suction valve 24 for opening and
closing the suction port 23, discharge port 25 and discharge valve
26 for opening and closing the discharge port 25. The suction
chamber 21 and each cylinder bore 1a are communicated with each
other via the suction port 23. Each cylinder bore 1a and the
discharge chamber 22 are communicated with each other via the
discharge port 25.
[0021] The suction chamber 21 and the crank chamber 5 are connected
with each other by the gas extraction passage 27 formed so that the
cylinder block 1 and the valve forming body 3 can be penetrated by
the gas extraction passage 27. The discharge chamber 22 and crank
chamber 5 are connected with each other by the gas supply passage
28. In the middle of the gas supply passage 28, there is provided a
control valve 29. The gas supply passage 28 is formed in the
peripheral wall section of the housing. The outlet 28A, which is an
opening on the crank chamber 5 side, is open to an upper portion of
the crank mechanism in the above peripheral wall section.
[0022] The control valve 29 adjusts the degree of opening of the
gas supply passage 28 according to a signal sent from a control
computer not shown in the drawing. When the degree of opening of
the gas supply passage 28 is adjusted, a quantity of high pressure
gas introduced into the crank chamber 5 via the gas supply passage
28 and a quantity of gas introduced out from the crank chamber 5
via the gas extraction passage 27 are controlled so that both the
quantities can be appropriately balanced. In this way, crank
pressure Pc (inner pressure in the crank chamber) can be
determined. According to a change in crank chamber pressure Pc, a
difference between crank pressure Pc via the piston 20 and the
inner pressure in the cylinder bore 1a is changed, so that an
inclination angle of the swash plate 12 is changed. As a result,
the stroke of the piston 20 can be changed, that is, the discharge
capacity can be changed.
[0023] The suction chamber 21 and the discharge chamber 22 are
connected with each other by the external refrigerant circuit 30.
The external refrigerant circuit 30 includes a condenser 31,
expansion valve 32 and evaporator 33. The external refrigerant
circuit 30 and the compressor C compose a refrigerating circuit of
the vehicle air conditioner.
[0024] In this connection, the mist-like lubricant is mixed in the
refrigerant gas flowing in the compressor C. Sliding portions of
the movable parts provided in the compressor C can be lubricated by
this mist-like lubricant.
[0025] Next, an action of the compressor composed as described
above will be explained below.
[0026] When power is supplied from the vehicle engine E to the
drive shaft 6 via the power transmission mechanism PT, the swash
plate 12 is rotated together with the drive shaft 6. According to
the rotation of the swash plate 12, each piston 20 is reciprocated
by a stroke corresponding to the inclination angle of the swash
plate 12, so that the refrigerant can be repeatedly sucked,
compressed and discharged in each cylinder bore 1a in this order.
The refrigerant gas supplied from the external refrigerant circuit
30 into the suction chamber 21 is sucked into the cylinder bore 1a
via the suction port 23 and compressed by the piston 20 when the
piston 20 is moved. After that, the refrigerant gas is discharged
into the discharge chamber 22 via the discharge port 25, so that it
is sent out into the external refrigerant circuit 30.
[0027] In the case where the cooling load is heavy, the control
valve 29 is adjusted so that the degree of opening of the gas
supply passage 28 can be decreased. Due to the foregoing, a
quantity of high pressure refrigerant gas supplied from the
discharge chamber 22 into the crank chamber 5 via the gas supply
passage 28 is decreased. Therefore, the pressure in the crank
chamber 5 is reduced, and the inclination angle of the swash plate
12 is increased. Accordingly, the discharge capacity of compressor
C can be increased. When the gas supply passage 28 is completely
closed, the pressure in the crank chamber 5 is greatly reduced, and
the inclination angle of the swash plate 12 is increased to the
maximum. Accordingly, the discharge capacity of the compressor C
becomes maximum.
[0028] On the contrary, in the case where the cooling load is
light, the control valve 29 is adjusted so that the degree of
opening of the gas supply passage 28 can be increased. Due to the
foregoing, the pressure in the crank chamber 5 is raised, and the
inclination angle of the swash plate 12 is decreased. Accordingly,
the discharge capacity of the compressor C is reduced. When the gas
supply passage 28 is completely opened, the pressure in the crank
chamber 5 is greatly raised, and the inclination angle of the swash
plate 12 is decreased to the minimum. Accordingly, the discharge
capacity of the compressor C becomes minimum.
[0029] The refrigerant gas sent from the gas supply passage 28 is
supplied to the crank chamber 5 from an upper portion of the crank
mechanism via the outlet 28A. At this time, mist-like lubricant
mixed in the refrigerant gas is also supplied from the outlet 28A
into the crank chamber 5. Therefore, the crank mechanism is mainly
lubricated, and also sliding portions of the movable parts in the
crank chamber 5 and sliding portions of the movable parts on the
cylinder block 1 side are lubricated.
[0030] According to this embodiment, the following effects can be
provided.
[0031] (1) The gas supply passage 28 including the outlet 28A is
arranged in the peripheral wall section of the compressor housing.
Due to the foregoing, the degree of freedom of the arrangement of
the outlet 28A can be enhanced. For example, compared with a case
in which the gas supply passage 28 is formed so that it can
penetrate the cylinder block 1 and the valve forming body 3 and in
which the outlet 28A is arranged so that it can be opened to the
cylinder block 1, it becomes easy to arrange that the outlet 28A
can be opened to the opposite side to the cylinder block 1 with
respect to the swash plate 12. A reaction force given to the piston
20 in the case of compression mainly acts in a direction so that
the crank mechanism and the drive shaft 6 can be pushed to the
front side of the compressor C. Therefore, the front side thrust
bearing 9A and the hinge mechanism 13 mainly receive the reaction
force. For the above reasons, in order to smoothly operate those
parts and the mechanism and in order to extend the life of those
parts and the mechanism, it becomes necessary to sufficiently
lubricate the sliding portions. Since the outlet 28A is arranged in
the peripheral wall section of the compressor housing, it becomes
possible to arrange the outlet 28A at a position where the front
side thrust bearing 9A and the hinge mechanism 13, which are
arranged on the opposite side to the cylinder block 1 with respect
to the swash plate 12, can be effectively lubricated. As a result,
the compressor C can be smoothly operated and the life of the
compressor C can be extended. Since the above effect can be
provided by the simple structure in which the outlet 28A is
arranged in the peripheral wall section of the compressor housing,
it is possible to expect that the manufacturing cost can be
reduced.
[0032] (2) The outlet 28A is open to an upper portion of the crank
mechanism in the peripheral wall section of the god housing of the
compressor C. Due to the above structure, the mist-like lubricant
can be easily spread all over the crank chamber 5. Accordingly, the
crank chamber 5 can be excellently lubricated. Especially, the
crank mechanism can be effectively lubricated. For example, even
when a quantity of the refrigerant supplied to the crank chamber 5
via the gas supply passage 28 is small, a quantity of the lubricant
supplied to the crank mechanism can be relatively increased because
the lubricant is supplied from the upper portion of the crank
mechanism.
[0033] In this connection, a state in which a quantity of the
refrigerant supplied to the crank case 5 via the gas supply passage
28 is small is caused not only by a case in which the degree of
opening of the gas supply passage 28 is adjusted to be small by the
control valve 29 but also by a case in which a small inclination
angle of the swash plate 12 (a small discharge capacity) is kept
over a long period of time. The reason is described as follows.
When operation is continued over a long period of time under the
condition that the discharge capacity is small, the inner pressure
in the discharge chamber 22 is gradually lowered, so that a
difference between the inner pressure in the discharge chamber 22
and crank chamber pressure Pc becomes small. Compared with a case
in which the degree of opening of the gas supply passage 28 is
adjusted to be small by the control valve 29, this state in which
the discharge capacity is small is kept over a long period of time
such as a period in which no operation is conducted in winter.
Therefore, in a state in which the discharge capacity is small, a
great advantage can be provided by the enhancement of the
lubrication efficiency.
[0034] (3) The control valve 29 is provided in the gas supply
passage 28. Due to the foregoing, the gas supply passage 28 can be
also used as a pressure adjusting hole for adjusting the inner
pressure in the crank chamber 5 by the control valve 29.
Accordingly, it becomes unnecessary to form the pressure adjusting
hole differently from the gas supply passage 28. Accordingly, the
structure can be made simple.
[0035] It should be noted that the present invention is not limited
to the above specific embodiment. For example, the following
embodiment may be adopted.
[0036] The compressor C may be of a type in which a wobble plate
and a drive shaft 6 are not integrally rotated, for example, the
compressor C may be of the wobble type.
[0037] Instead of arranging the control valve 29 in the gas supply
passage 28, the control valve may be arranged in the gas extraction
passage 27. According to this arrangement, when the control valve
adjusts the degree of opening of the gas extraction passage 27, a
quantity of the refrigerant introduced out from the crank chamber 5
via the gas extraction passage 27 and a quantity of refrigerant
introduced in via the gas supply passage 28 are controlled so that
they can be balanced. In this way, the crank chamber pressure Pc
can be changed.
[0038] The type of control may not be an external control type in
which the degree of opening of the control valve 29 is adjusted by
the control conducted from the outside, but the type of control may
be an internal control type in which the degree of opening of the
control valve 29 is adjusted by the independent control of the
control valve itself. However, in the clutchless type compressor
described in the above embodiment, it is preferable to use the
control valve 29 of the external control type.
[0039] The piston type variable displacement compressor of the
present invention may be any of the compressor in which the swash
plate and the drive shaft are integrally rotated and the compressor
in which the swash plate and the drive shaft are not integrally
rotated. In this case, in any of the piston type variable
displacement compressors, the crank chamber can be excellently
lubricated by a simple structure in any operating condition.
[0040] Further, the aforementioned outlet 28A may be formed toward
the thrust bearing for supporting the crank mechanism in the axial
direction of the drive shaft and/or the hinge mechanism for
changing a stroke of the piston. In this case, the thrust bearing
and the hinge mechanism can be effectively lubricated.
[0041] Further, in the piston type variable displacement compressor
of the present invention, a gas extraction passage for introducing
the refrigerant from the crank chamber into the low pressure region
may be provided, and a control valve for changing a quantity of the
refrigerant introduced from the crank chamber into the low pressure
region may be provided in this gas extraction passage. In this
case, the gas extraction passage can be also used as a pressure
adjusting hole for adjusting the inner pressure in the crank
chamber by the control valve.
[0042] As described above in detail, in the piston type variable
displacement compressor according to the present invention, it is
possible to lubricate the crank chamber by a simple structure in
any operating condition.
[0043] While the invention has been described by reference to
specific embodiments chosen for purposes of illustration, it should
be apparent that numerous modifications could be made thereto by
those skilled in the art without departing from the basic concept
and scope of the invention.
* * * * *