U.S. patent application number 11/360356 was filed with the patent office on 2006-10-05 for swash plate type variable displacement compressor.
Invention is credited to Akinobu Kanai, Osamu Nakayama, Masaki Ota, Akihito Yamanouchi.
Application Number | 20060222513 11/360356 |
Document ID | / |
Family ID | 36848334 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060222513 |
Kind Code |
A1 |
Ota; Masaki ; et
al. |
October 5, 2006 |
Swash plate type variable displacement compressor
Abstract
A swash plate type variable displacement compressor includes a
housing, a drive shaft, a piston, a lug plate, a swash plate, a
hinge mechanism provided between the lug plate and the swash plate,
and a control mechanism. The hinge mechanism includes a restraining
hinge element that is located on a suction side with respect to a
first imaginary plane that includes a top position of the swash
plate corresponding to the top dead center position of the piston
and the axis of the drive shaft for restraining the lug plate and
the swash plate from rotating relative to each other and the swash
plate to move away from the lug plate. The hinge mechanism further
includes a non-restraining hinge element that is located on a
discharge side with respect to the first imaginary plane for not
restraining the swash plate from moving away from the lug
plate.
Inventors: |
Ota; Masaki; (Kariya-shi,
JP) ; Nakayama; Osamu; (Kariya-shi, JP) ;
Kanai; Akinobu; (Kariya-shi, JP) ; Yamanouchi;
Akihito; (Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
3 World Financial Center
New York
NY
10281-2101
US
|
Family ID: |
36848334 |
Appl. No.: |
11/360356 |
Filed: |
February 22, 2006 |
Current U.S.
Class: |
417/222.2 |
Current CPC
Class: |
F04B 27/1072
20130101 |
Class at
Publication: |
417/222.2 |
International
Class: |
F04B 1/26 20060101
F04B001/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 4, 2005 |
JP |
2005-060752 |
Claims
1. A swash plate type variable displacement compressor for
compressing a refrigerant, comprising: a housing defining therein a
cylinder bore, a crank chamber, a suction chamber and a discharge
chamber; a piston reciprocatably accommodated in the cylinder bore
and defining a compression chamber in the cylinder bore; a drive
shaft driven by an external drive source and rotatably supported by
the housing; a lug plate supported by the drive shaft in the crank
chamber so as to rotate with the drive shaft; a swash plate
supported by the drive shaft in the crank chamber; a hinge
mechanism provided between the lug plate and the swash plate, the
swash plate being rotatable with and inclinable relative to the
drive shaft through the lug plate and the hinge mechanism for
reciprocating the piston through shoes; and a control mechanism
operable to control a pressure in the crank chamber thereby to vary
an amount of the refrigerant discharged from the compression
chamber into the discharge chamber by the reciprocation of the
piston based on an inclination angle of the swash plate, wherein
the hinge mechanism includes a restraining hinge element that is
located on a suction side with respect to a first imaginary plane
that includes a top position of the swash plate corresponding to a
top dead center position of the piston and an axis of the drive
shaft for restraining the lug plate and the swash plate from
rotating relative to each other and the swash plate to move away
from the lug plate, the hinge mechanism further including a
non-restraining hinge element that is located on a discharge side
with respect to the first imaginary plane for not restraining the
swash plate from moving away from the lug plate.
2. The swash plate type variable displacement compressor according
to claim 1, wherein the restraining hinge element includes a
support arm that is provided on one of the lug plate and the swash
plate and that has a guide hole with an inner circumferential
surface and a guide pin that is provided on the other one of the
lug plate and the swash plate and that has a spherical portion for
sliding in the guide hole.
3. The swash plate type variable displacement compressor according
to claim 1, wherein the non-restraining hinge element is provided
so as not to restrain the lug plate and the swash plate from
rotating relative to each other.
4. The swash plate type variable displacement compressor according
to claim 3, wherein the non-restraining hinge element includes a
first guide surface that is provided on one of the lug plate and
the swash plate facing toward the other one of the lug plate and
the swash plate and a second guide surface that is provided on the
other one of the lug plate and the swash plate facing toward the
first guide surface, the second guide surface being contactable
with the first guide surface.
5. The swash plate type variable displacement compressor according
to claim 1, wherein the hinge mechanism is located on a side of the
top position of the swash plate with respect to a second imaginary
plane that includes the axis of the drive shaft and is
perpendicular to the first imaginary plane, a surface of the swash
plate that faces toward the lug plate providing a receiving surface
that is located on the suction side with respect to the first
imaginary plane and on a side opposite to the top position with
respect to the second imaginary plane for contacting with the lug
plate when the swash plate is inclined at a maximum inclination
angle thereby to regulate the maximum inclination angle of the
swash plate.
6. The swash plate type variable displacement compressor according
to claim 5, wherein the receiving surface is formed on a weight
portion that is provided in the swash plate.
7. The swash plate type variable displacement compressor according
to claim 5, wherein the receiving surface is located at a position
within a range where the receiving surface is contactable with the
lug plate, which is furthest from the axis of the drive shaft.
8. The swash plate type variable displacement compressor according
to claim 1, wherein the drive shaft is constantly driven while the
external drive source is running.
9. The swash plate type variable displacement compressor according
to claim 1, wherein the swash plate has an elongated hole with
parallel facing surfaces for receiving an outer circumferential
surface of the drive shaft.
10. The swash plate type variable displacement compressor according
to claim 1, wherein the control mechanism includes a supply passage
for connecting the discharge chamber to the crank chamber, a bleed
passage for connecting the crank chamber to the suction chamber and
a displacement control valve disposed in the supply passage.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a swash plate type variable
displacement compressor.
[0002] Japanese Patent Application Publication No. 9-203377
discloses a conventional swash plate type variable displacement
compressor (hereinafter referred to merely as "compressor"). The
compressor includes a housing that defines therein a cylinder bore,
a crank chamber, a suction chamber and a discharge chamber, a
piston that is reciprocatably accommodated in the cylinder bore for
defining a compression chamber and a drive shaft that is driven by
an external drive source and rotatably supported by the housing.
The compressor further includes a lug plate that is supported in
the crank chamber so as to rotate integrally with the drive shaft
and a swash plate that is supported in the housing so as to rotate
integrally with and incline relative to the drive shaft through the
lug plate and a hinge mechanism for reciprocating the piston
through shoes. The swash plate has an elongated hole which is
formed at the center thereof with parallel facing surfaces and
through which the drive shaft is inserted for receiving the outer
circumferential surface of the drive shaft. Furthermore, the
compressor includes a control mechanism for controlling the
pressure in the crank chamber.
[0003] The hinge mechanism of the compressor includes an arm and an
engaging groove as a non-restraining hinge element, which is
located adjacent to the top position of the swash plate
corresponding to the top dead center position of the piston and on
an imaginary plane including the top position and the axis of the
drive shaft and does not restrain the swash plate from moving away
from the lug plate. The arm is provided on the swash plate and has
a first guide surface that faces toward the lug plate. The engaging
groove is formed in the lug plate and has a second guide surface
that is contactable with the first guide surface. In the
non-restraining hinge element, the top end of the arm is held in
the engaging groove, thereby restraining the lug plate and the
swash plate from rotating relative to each other.
[0004] The compressor constructed as described above constitutes
together with a condenser, an expansion valve and an evaporator a
refrigerant circuit for use in a vehicle. As the drive shaft is
driven by an engine or the like as the external drive source and
the swash plate is rotated at an inclined angle, the piston is
reciprocated in the cylinder bore. Thus, a refrigerant gas is drawn
from the suction chamber into the compression chamber in the
cylinder bore, compressed and then discharged into the discharge
chamber. The control mechanism adjusts the pressure in the crank
chamber so as to vary the inclination angle of the swash plate,
thereby controlling the amount of the refrigerant gas discharged
from the compression chamber into the discharge chamber. Thus,
cooling performance in accordance with the discharged amount of the
refrigerant gas is achieved by the refrigerant circuit.
[0005] During operation of the compressor, a compression reactive
force and a suction force of the refrigerant gas are applied to the
swash plate through the piston and the shoes thereby to create a
moment thereon which urges the swash plate to turn around the
intersection line between the swash plate and the above imaginary
plane to be inclined relative to the drive shaft. In the
non-restraining hinge element in which the top end of the arm is
held in the engaging groove, both side surfaces of the arm are
brought into contact with the inner side wall surfaces of the
engaging groove, respectively, thereby to receive the moment. The
elongated hole formed at the center of the swash plate receives the
moment at the parallel facing surfaces thereof.
[0006] Japanese Patent Publication No. 2917767 discloses a
compressor having a hinge mechanism that is different from the
above-described hinge mechanism. In this compressor, the hinge
mechanism includes a pair of restraining hinge elements that are
located on the suction side and the discharge side, respectively,
with respect to the above imaginary plane for restraining the lug
plate and the swash plate from rotating relative to each other and
the swash plate from moving away from the lug plate, in place of
the above-described arm and the engaging groove as the
non-restraining hinge element. Each of the restraining hinge
elements includes a support arm that is provided on the lug plate
and has a guide hole, and a guide pin that is provided on the swash
plate and has a spherical portion for sliding in the guide
hole.
[0007] In the above-described compressor of Japanese Patent
Publication No. 2917767, the pressure in the crank chamber is
adjusted by the control mechanism to vary the inclination angle of
the swash plate, thereby controlling the amount of refrigerant gas
discharged from the compression chamber into the discharge chamber,
as in the compressor of Japanese Patent Application Publication No.
9-203377.
[0008] During operation of the compressor, the pair of restraining
hinge elements receive the moment that urges the swash plate to
turn around the intersection line between the swash plate and the
above imaginary plane to be inclined relative to the drive shaft.
Also, the elongated hole formed at the center of the swash plate
also receives the moment at the parallel facing surfaces.
[0009] However, problems arise in the above compressors in the
reduction of vibration and noise during operation of the compressor
as described below.
[0010] In the compressor of Japanese Patent Application Publication
No. 9-203377, when the compressor operates at a high speed and
under a large displacement in a state where the refrigerant is
insufficient in the refrigerant circuit, the piston reciprocates
for a large stroke length at high speed, but the discharge pressure
is not increased to a desired value due to the insufficient
refrigerant gas. Thus, the inertial force of the piston tends to
become greater than the compression reactive force, thereby
creating a moment acting on the swash plate to urge the inclination
angle of the swash plate to be increased. The hinge mechanism of
Japanese Patent Application Publication No. 9-203377 having the
non-restraining hinge element with no function of restraining the
swash plate from moving away from the lug plate does not receive
the above moment created by the excessive inertial force of the
piston and urging the swash plate to be inclined further. Thus,
there is a fear that the swash plate may be inclined beyond its
maximum inclination angle. In this case, the piston reciprocates
for a distance longer than the maximum stroke and the piston head
collides against the suction valve at the top wall of the
compression chamber, with the result that abnormal noise and
vibration are generated.
[0011] In the compressor of Japanese Patent Publication No.
2917767, since the hinge mechanism has the pair of restraining
hinge elements that restrain the swash plate from moving away from
the lug plate, the hinge mechanism receives the moment created by
the above excessive inertial force of the piston and urging the
swash plate to be inclined further. Therefore, the swash plate is
not inclined beyond its maximum inclination angle and, therefore,
generation of abnormal noise and vibration due to the excessive
inclination of the swash plate beyond the maximum inclination angle
is prevented.
[0012] However, in the compressor of Japanese Patent Publication
No. 2917767, each of the restraining hinge elements restrains the
lug plate and the swash plate from rotating relative to each other
and the swash plate from moving away from the lug plate and, for
ensuring smooth movement of the hinge mechanism, the clearance of
each restraining hinge element needs to be enlarged appropriately.
This is because reducing the clearance of the restraining hinge
element while simultaneously ensuring the accuracy of positioning
of the restraining hinge elements is difficult in view of
production cost and productivity of compressors which are usually
mass-produced. Large clearance of the restraining hinge elements
may cause a play between the swash plate and the shoes and also
between the shoes and the piston. When the compressor is operating
under its minimum displacement, the compression reactive force and
the suction force acting on the swash plate become minimum and,
therefore, abnormal and hence unpleasant noise and vibration may be
generated in the compressor around the swash plate, shoes and a
piston. Such a compressor which is mounted in a vehicle may
discomfort a vehicle occupant therein.
[0013] The present invention is directed to a swash plate type
variable displacement compressor that reduces the generation of
noise and vibration in operation.
SUMMARY OF THE INVENTION
[0014] According to the present invention, a swash plate type
variable displacement compressor for compressing a refrigerant
includes a housing, a drive shaft, a piston, a lug plate, a swash
plate, a hinge mechanism and a control mechanism. The housing
defines therein a cylinder bore, a crank chamber, a suction chamber
and a discharge chamber. The piston is reciprocatably accommodated
in the cylinder bore and defines a compression chamber in the
cylinder bore. The drive shaft is driven by an external drive
source and rotatably supported by the housing. The lug plate is
supported by the drive shaft in the crank chamber so as to rotate
with the drive shaft. The swash plate is supported by the drive
shaft in the crank chamber. The hinge mechanism is provided between
the lug plate and the swash plate. The swash plate is rotatable
with and inclinable relative to the drive shaft through the lug
plate and the hinge mechanism for reciprocating the piston through
shoes. The control mechanism is operable to control a pressure in
the crank chamber thereby to vary an amount of the refrigerant
discharged from the compression chamber into the discharge chamber
by the reciprocation of the piston based on an inclination angle of
the swash plate. The hinge mechanism includes a restraining hinge
element that is located on a suction side with respect to a first
imaginary plane that includes a top position of the swash plate
corresponding to a top dead center position of the piston and an
axis of the drive shaft for restraining the lug plate and the swash
plate from rotating relative to each other and the swash plate to
move away from the lug plate. The hinge mechanism further includes
a non-restraining hinge element that is located on a discharge side
with respect to the first imaginary plane for not restraining the
swash plate from moving away from the lug plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The features of the present invention that are believed to
be novel are set forth with particularity in the appended claims.
The invention together with objects and advantages thereof, may
best be understood by reference to the following description of the
presently preferred embodiments together with the accompanying
drawings in which:
[0016] FIG. 1 is a longitudinal cross-sectional view of a swash
plate type variable displacement compressor according to a
preferred embodiment of the present invention;
[0017] FIG. 2 is a partially enlarged cross-sectional view of the
compressor according to the preferred embodiment of the present
invention as seen from the back side of FIG. 1;
[0018] FIG. 3 is a top view of a swash plate according to the
preferred embodiment of the present invention;
[0019] FIG. 4 is a front view of the swash plate according to the
preferred embodiment of the present invention;
[0020] FIG. 5 is a partially enlarged cross-sectional view of the
compressor according to the preferred embodiment of the present
invention showing the inclination of the swash plate at a minimum
inclination angle;
[0021] FIG. 6 is a partially enlarged cross-sectional view of the
compressor according to the preferred embodiment of the present
invention as seen from the back side of FIG. 5 and showing the
inclination of the swash plate at a minimum inclination angle;
and
[0022] FIG. 7 is a schematic top view of the swash plate, the hinge
mechanism and a lug late according to the preferred embodiment of
the present invention showing the relationship between the lug
plate and the swash plate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The following will describe a preferred embodiment according
to the present invention with reference to FIGS. 1 through 7.
Referring to FIG. 1, the swash plate type variable displacement
compressor 10 of the preferred embodiment (hereinafter referred to
as "compressor") has a housing 1, single-headed pistons 31, a drive
shaft 16, a lug plate 24, a swash plate 25 and a control mechanism
4. In FIG. 1, the left side and the right side correspond to the
front side and rear side of the compressor 10, respectively.
[0024] The housing 1 includes a cylinder block 11, a front housing
12 joined to the front end of the cylinder block 11 and a rear
housing 13 joined to the rear end of the cylinder block 11 through
a valve plate 14. The front housing 12 and the rear housing 13 are
fixed to the cylinder block 11 by bolts (not shown). The cylinder
block 11 and the front housing 12 cooperate to define therein a
crank chamber 15.
[0025] The drive shaft 16 is rotatably supported by the cylinder
block 11 and the front housing 12. More specifically, a coil spring
17 and a thrust bearing 18 are disposed in a shaft hole 80 formed
in the cylinder block 11 at the center thereof, and the drive shaft
16 is supported at the rear end thereof by the thrust bearing 18
that is urged forward by the coil spring 17. The drive shaft 16 is
supported also at a position adjacent to the front end thereof by a
radial bearing 19 that is disposed in a shaft hole 81 formed in the
front housing 12. A seal device 20 is provided in the shaft hole 81
in front of the radial bearing 19. Furthermore, the drive shaft 16
is connected at the front end thereof to a pulley 21 which is
provided on the front end of the front housing 12 through a bearing
90. The pulley 21 is rotatable with the drive shaft 16. The pulley
21 is connected through a belt 91 to a vehicle engine as an
external drive source. Thus, the compressor 10 is constantly driven
by the engine during operation of the engine.
[0026] The lug plate 24 is press fitted on the drive shaft 16 in
the crank chamber 15. A thrust bearing 27 is provided between the
lug plate 24 and the inner wall surface of the front housing 12.
The swash plate 25 is mounted on the drive shaft 16 and has an
elongated hole 22 through which the drive shaft 16 is inserted. The
elongated hole 22 is formed at the center of the swash plate 25 and
has parallel facing surfaces 23 for receiving the outer
circumferential surface of the drive shaft 16 as shown in FIGS. 3
and 4. A hinge mechanism 26 is provided between the lug plate 24
and the swash plate 25.
[0027] Referring to FIG. 1, a spring 28 is provided on the drive
shaft 16 between the lug plate 24 and the swash plate 25. The
spring 28 serves to urge the swash plate 25 toward the cylinder
block 11, that is, in the direction that causes the inclination
angle of the swash plate 25 to be decreased. A circlip 29 is fixed
on the drive shaft 16 behind the swash plate 25. A spring 30 is
provided on the drive shaft 16 between the circlip 29 and the swash
plate 25. When pressed by the swash plate 25, the spring 30 serves
to urge the swash plate 25 away from the cylinder block 11, that
is, in the direction that causes the inclination angle of the swash
plate 25 to be increased.
[0028] The cylinder block 11 defines therein a plurality of
cylinder bores 11a that are equiangularly arranged around the drive
shaft 16. Only one cylinder bore 11a is shown in the drawings. Each
of the cylinder bores 11a extends parallel to the drive shaft 16,
and the piston 31 is reciprocatably disposed therein. Each of the
pistons 31 is engaged at the front end thereof with the outer
periphery of the swash plate 25 through a pair of shoes 32. Each
shoe 32 has a substantially semispherical surface in contact with
the piston 31 and a flat surface in contact with the swash plate
25. The paired shoes 32 are disposed on the opposite sides of the
swash plate 25 so that they form a substantial spherical shape.
[0029] A compression chamber 33 is defined in each cylinder bore
11a between the piston head of the pistons 31 on the rear side and
the valve plate 14. When the swash plate 25 is rotated with the
drive shaft 16 while being inclined relative to the drive shaft 16,
a wobbling motion of the swash plate 25 is generated thereby to
reciprocate each of the pistons 31 through the associated paired
shoes 32. In this manner, the rotation of the drive shaft 16 is
converted into the reciprocating movement of the pistons 31 through
the swash plate 25 and the shoes 32.
[0030] The rear housing 13 defines therein a discharge chamber 34
and an annular suction chamber 35 surrounding the discharge chamber
34. The suction chamber 35 is connected to a refrigerant circuit 37
on the downstream side through an inlet 36 formed in the rear
housing 13. The discharge chamber 34 is connected to the
refrigerant circuit 37 on the upstream side through an outlet 38
formed in the rear housing 13. The refrigerant circuit 37 includes
a condenser 39, an expansion valve 40 and an evaporator 41.
[0031] The valve plate 14 has a suction port 42 and a discharge
port 43 that are correspondingly disposed in relation to each
compression chamber 33. The valve plate 14 also has a suction valve
42a and a discharge valve 43a that are correspondingly disposed in
relation to each suction port 42 and each discharge port 43,
respectively. During the suction stroke of the piston 31, a
refrigerant gas in the suction chamber 35 is drawn into the
compression chamber 33 through its associated suction port 42 while
pushing open the suction valve 42a. During the compression stroke
of the piston 31, on the other hand, the refrigerant gas is
compressed in the compression chamber and then discharged out
thereof into the discharge chamber 34 through its associated
discharge port 43 while pushing open the discharge valve 43a.
[0032] A supply passage 44 is formed in the cylinder block 11, the
valve plate 14 and the rear housing 13 for connecting the discharge
chamber 34 to the crank chamber 15. A bleed passage 45 is formed in
the cylinder block 11, the valve plate 14 and the rear housing 13
for connecting the crank chamber 15 to the suction chamber 35. The
bleed passage 45 has therein an orifice (not shown). As shown in
FIG. 1, a displacement control valve 46 is disposed in the supply
passage 44. For example, the displacement control valve 46 is
similar in construction to that which is disclosed in Japanese
Patent Application Publication No. 2003-239857. The supply passage
44, the bleed passage 45 and the displacement control valve 46
constitute the control mechanism 4 which is operable to control the
pressure in the crank chamber 15.
[0033] The control mechanism 4 controls the opening and closing of
the supply passage 44 by the displacement control valve 46
according to the variation of the pressure in the suction chamber
35 thereby to increase or decrease the pressure in the crank
chamber 15 for regulating the displacement of the compressor 10.
When cooling load is small and the pressure in the suction chamber
35 is low, the degree of opening of the displacement control valve
46 is increased thereby to increase the pressure in the crank
chamber 15 and the inclination angle of the swash plate 25 is
decreased, accordingly. As a result, the stroke of each piston 31
is decreased thereby to decrease the displacement of the compressor
10. On the other hand, when the cooling load is large and the
pressure in the suction chamber 35 is high, the opening degree of
the displacement control valve 46 is decreased thereby to decrease
the pressure in the crank chamber 15 with the result that the
inclination angle of the swash plate 25 is increased and the stroke
of each of the pistons 31 is increased thereby to increase the
displacement of the compressor 10. The opening degree of the
displacement control valve 46 is variable externally according to
the manner of operation such as acceleration of a vehicle or the
like. The surface of the swash plate 25 facing toward the lug plate
24 provides a receiving surface 25a as will be described later. The
receiving surface 25a comes into contact with the lug plate 24
thereby to regulate the maximum inclination angle of the swash
plate 25.
[0034] The following will describe the construction of the hinge
mechanism 26 in detail. In the compressor 10 of the preferred
embodiment, the drive shaft 16 is rotated in the direction
indicated by an arrow Z in FIG. 1. Referring to FIG. 4, reference
symbol CP designates a first imaginary plane containing therein the
top position A of the swash plate 25 and the longitudinal axial 01
of the drive shaft 16. The top position A of the swash plate 25
corresponds to the top dead center position of the piston 31, and
more specifically places the piston 31 at its top dead center. The
cross-section taken along this imaginary plane CP substantially
corresponds to the cross-section of FIG. 1. Reference symbol SP in
FIG. 4 designates a second imaginary plane which extends
perpendicularly to the above plane CP. It is noted that the swash
plate 25 is inclined at the maximum inclination angle in FIG. 1. In
FIGS. 3 and 4, the left side and the right side of the swash plate
25 with respect to the first imaginary plane CP correspond to the
side on which suction takes place and the other side on which
discharge takes place in the compressor 10, respectively. In other
words, in FIG. 1, the viewer side and the back side thereof
correspond to the discharge side and the suction side,
respectively. In FIG. 2, the viewer side and the back side thereof
correspond to the suction side and the discharge side,
respectively. Namely, FIG. 1 is a cross-sectional view of the
compressor 10 showing the elements located on the suction side with
respect to the first imaginary plane CP. FIG. 2 is an enlarged
cross-sectional view of the compressor 10 showing the elements
located on the discharge side with respect to the first imaginary
plane CP.
[0035] The hinge mechanism 26 includes a support arm 61 and a guide
pin 62 which are located on the suction side with respect to the
first imaginary plane CP as shown in FIG. 1, and serve as a
restraining hinge element 60. The hinge mechanism 26 also includes
a first guide surface 71 and a second guide surface 72 which are
located on the discharge side with respect to the first imaginary
plane CP as shown in FIG. 2, and serve as a non-restraining hinge
element 70. As shown in FIGS. 3 and 4, the guide pin 62 and the
second guide surface 72 are provided on the front surface of the
swash plate 25. As shown in FIGS. 1 and 2, the support arm 61 and
the first guide surface 71 are provided on the rear surface of the
lug plate 24 facing toward the swash plate 25 and correspondingly
disposed in relation to the guide pin 62 and the second guide
surface 72, respectively.
[0036] In the restraining hinge element 60, the support arm 61 has
a guide hole 61a with an inner circumferential surface, in which a
spherical portion 62a provided at the top end of the guide pin 62
is slidable. Thus, the support arm 61 and the guide pin 62 as the
restraining hinge element 60 serve to restrain the lug plate 24 and
the swash plate 25 from rotating relative to each other and the
swash plate 25 from moving away from the lug plate 24.
[0037] In the non-restraining hinge element 70, the first and
second guide surfaces 71 and 72 face each other and are contactable
with each other. It is noted that the non-restraining hinge element
70 does not include a side wall for restraining the lug plate 24
and the swash plate 25 from rotating relative to each other and a
side wall for restraining the swash plate 25 from moving away from
the lug plate 24. Thus, the first and second guide surfaces 71 and
72 as the non-restraining hinge element 70 have no function of
restraining the lug plate 24 and the swash plate 25 from rotating
relative to each other and the swash plate 25 from moving away from
the lug plate 24.
[0038] According to the above construction, when manufacturing the
non-restraining hinge element 70, only the first and second guide
surfaces 71 and 72, which support the swash plate 25 together with
the restraining hinge element 60 so that the swash plate 25 is
inclined at a desired angle, may be formed with high accuracy.
Furthermore, the positioning accuracy of the first and second guide
surfaces 71 and 72 relative to the restraining hinge element 60 may
be lessened. Unlike the paired restraining hinges in the compressor
disclosed in Japanese Patent Publication No. 2917767, therefore,
there is no need to enlarge the clearance between the support arm
61 and the guide pin 62 of the restraining hinge element 60.
Accordingly, it is possible to make the clearance between the
support arm 61 and the guide pin 62 smaller by manufacturing these
support arm 61 and guide pin 62 with the desired accuracy. More
specifically, the clearance between the guide hole 61a and the
spherical portion 62a can be easily made smaller by ensuring the
accuracy of the directions of the axes of the guide hole 61a and
the guide pin 62 and of the diameters of the guide hole 61a and the
spherical portion 62a. As a result, the swash plate 25 fits the
restraining and non-restraining hinge elements 60 and 70 with less
clearance (or backlash).
[0039] Thus, the restraining and non-restraining hinge elements 60
and 70 of the hinge mechanism 26 are provided between the swash
plate 25 and the lug plate 24 and serve to support the swash plate
25 so that it is inclined at an angle as required. For example,
when the swash plate 25 is inclined at the minimum inclination
angle as shown in FIGS. 5 and 6, the hinge mechanism 26 supports
the swash plate 25 with the guide pin 62 of the restraining hinge
element 60 and the second guide surface 72 of the non-restraining
hinge element 70 slid and located at certain positions.
[0040] The non-restraining hinge element 70 dispenses with a side
wall for restraining the lug plate 24 and the swash plate 25 from
rotating relative to each other, so that the non-restraining hinge
70 can be made light in weight.
[0041] The following will describe the receiving surface 25a of the
swash plate 25 in detail. Referring to FIGS. 1 through 4, the hinge
mechanism 26 is located on the side of the top position A with
respect to the second imaginary plane SP. The surface of the swash
plate 25 facing toward the lug plate 24 provides the receiving
surface 25a which is located on the suction side with respect to
the first imaginary plane CP and on the side of the bottom position
B opposite to the top position A with respect to the second
imaginary plane SP. The bottom position B corresponds to the bottom
dead center position of the piston 31. The receiving surface 25a is
formed by smoothly machining a small area of a weight portion 25b
of the swash plate 25 projecting from the swash plate 25 toward the
lug plate 24. The receiving surface 25a is located at a position
within a range where the receiving surface 25a is contactable with
the lug plate 24, which is furthest from the axis O1 of the drive
shaft 16, that is, furthest from an intersecting point between a
line O2 passing through the axes of the restraining hinge element
60 and the swash plate 25 and a line O3 passing through the center
of the receiving surface 25a and perpendicularly to the line O2, as
shown in FIG. 4. In this way, the receiving surface 25a is adapted
to restrain the swash plate 25 from being inclined beyond the
maximum inclination angle by contacting with the lug plate 24 when
the swash plate 25 is inclined to its maximum inclination angle
position as shown in FIG. 1.
[0042] The above-described compressor 10 of the preferred
embodiment constitute together with the condenser 39, the expansion
valve 40 and the evaporator 41 the refrigerant circuit 37, for
example, for use in a vehicle. In the compressor 10, the drive
shaft 16 is driven to rotate by the engine or the like as the
external drive source thereby to rotate the swash plate 25 inclined
at an angle through the restraining hinge element 60, which serves
to restrain the lug plate 24 and the swash plate 25 from rotating
relative to each other. The wobbling motion of the swash plate 25
is transmitted to the piston 31 through the shoes 32 thereby to
reciprocate the piston 31 in the associated cylinder bore 11a.
Thus, the refrigerant gas is drawn from the suction chamber 35 into
the compression chamber 33 in the cylinder bore 11a, compressed and
then discharged into the discharge chamber 34. The pressure in the
crank chamber 15 is adjusted by the supply passage 44, the bleed
passage 45 and the displacement control valve 46 to vary the
inclination angle of the swash plate 25, thereby controlling the
amount of the refrigerant gas discharged from the compression
chamber 33 into the discharge chamber 34 (or the displacement of
the compressor 10). Thus, cooling performance in accordance with
the displacement of the compressor 10 is achieved by the
refrigerant circuit 37.
[0043] During operation of the compressor 10, as shown in FIG. 7, a
compression reactive force P1 and a suction force P2 of the
refrigerant gas are applied to the swash plate 25 through the
piston 31 and the shoes 32 thereby to create a moment M on the
swash plate 25, which urges the swash plate to turn around the line
of intersection between the swash plate 25 and the first imaginary
plane CP to be inclined relative to the drive shaft 16. More
specifically, the moment M acts on the swash plate 25 in such a way
that the suction force P2 urges the swash plate 25 on the suction
side of the first plane CP to move away from the lug plate 24 and
the compression reactive force P1 urges the swash plate 25 on the
discharge side of the first plane CP to press against the lug plate
24.
[0044] The support arm 61 and the guide pin 62 located on the
suction side with respect to the first imaginary plane CP and
serving as the restraining hinge element cooperate to restrain the
swash plate 25 from moving away from the lug plate 24. Thus, the
restraining hinge element 60 receives the part of the moment M that
urges the swash plate 25 on the suction side with respect to the
first imaginary plane CP to be moved away from the lug plate 24 by
the suction force P2.
[0045] The first and second guide surfaces 71 and 72 as the
non-restraining hinge element 70 receive the part of the moment M
that urges the swash plate 25 on the discharge side with respect to
the first imaginary plane CP to be pressed against the lug plate 24
by the compression reactive force P1. The part of the moment M that
urges the swash plate 25 to be moved away from the lug plate 24 by
the suction force P2 is not applied to the non-restraining hinge
element 70, so that the non-restraining hinge element 70 does not
need to restrain the swash plate 25 from moving away from the lug
plate 24. When the compressor 10 is operating at a high speed and
under a large displacement capacity in the state where the
refrigerant gas is insufficient in the refrigerant circuit 37 and,
therefore, the inertial force of the piston 31 becomes excessively
large thereby to create a moment M that tends to further increase
the inclination angle of the swash plate 25, the support arm 61 and
the guide pin 62 as the restraining hinge element 60 of the hinge
mechanism 26 can receive this moment M. Therefore, the compressor
10 does not generate noise and vibration which are caused by
excessive inclination of the swash plate 25 beyond the maximum
inclination angle. Namely, the compressor 10 reduces the generation
of noise and vibration in operation.
[0046] In the compressor 10 of the preferred embodiment, the
restraining hinge element 60 includes the support arm 61 which is
provided on the lug plate 24 and has the guide hole 61a with the
inner circumferential surface, and the guide pin 62 which is
provided on the swash plate 25 and has the spherical portion 62a
slidable in the guide hole 61a. When the guide pin 62 slides in the
guide hole 61a, the spherical portion 62a keeps a smooth contact
with the inner circumferential surface of the guide hole 61a, thus
providing excellent durability for the hinge mechanism. The
clearance between the guide hole 61a and the spherical portion 62a
is easily made smaller by ensuring the accuracy of the directions
of the axes of the guide hole 61a and the guide pin 62 and of the
diameters of the guide hole 61a and the spherical portion 62a. As a
result, the above advantageous effect of reducing the generation of
noise and vibration is achieved with more certainty.
[0047] In the compressor 10 of the preferred embodiment, the
non-restraining hinge element 70 neither restrains nor need to
restrain the lug plate 24 and the swash plate 25 from rotating
relative to each other. Thus, weight reduction is achieved in
addition to the above advantageous effect, thus improving the
controllability of the compressor such as response to the variation
of rotational speed of the drive shaft 16.
[0048] In the compressor 10 of the preferred embodiment, the
non-restraining hinge element 70 includes the first guide surface
71 which is provided on the lug plate 24 and faces toward the swash
plate 25 and the second guide surface 72 which is provided on the
swash plate 25 and faces toward the first guide surface 71. When
manufacturing the non-restraining hinge element 70, only the first
and second guide surfaces 71 and 72 need to be machined with high
accuracy and, therefore, the manufacturing of the non-restraining
hinge element 70 is facilitated, with the result that production
cost of the compressor 10 is further reduced.
[0049] In the compressor 10 of the preferred embodiment, the hinge
mechanism 26 is located on the side of the top position A with
respect to the second imaginary plane SP. This stabilizes the top
dead center position of the piston 31 regardless of the inclination
angle thereof. Thus, the volume of the compression chamber 33 that
is defined by the head of the piston 31 located at the top dead
center position (or top clearance) is made smaller, thereby
suppressing the re-expansion of the refrigerant gas in the
compression chamber 33.
[0050] Additionally, in the preferred embodiment, the swash plate
25 on the side of the top position A with respect to the second
imaginary plane SP and on the suction side with respect to the
first imaginary plane Cp is restrained from moving by the
restraining hinge element 60. The swash plate 25 at the center
thereof is restrained from moving by the parallel facing surfaces
23 of the elongated hole 22. However, the swash plate 25 is not
restrained from turning about the line O2. When the compressor 10
operates at a low speed, the resultant force of the compression
reactive force and the inertial force of the piston 31 is applied
to the swash plate 25 on the discharge side with respect to the
first imaginary plane CP and on the side of the top position A with
respect to the second imaginary plane SP. Namely, the resultant
force urges the portion of the swash plate 25 adjacent to the
non-restraining hinge element 70 to press against the lug plate 24,
that is, urges the second guide surface 72 to press against the
first guide surface 71, thus stably supporting the swash plate
25.
[0051] When the compressor 10 operates at a high speed, for
example, when the rotational speed of the drive shaft 16 is
increased (e.g. 4000 to 5000 rpm or more), the resultant force is
applied to the swash plate 25 on the side of the bottom position B
opposite to the top position A with respect to the second imaginary
plane SR Namely, the resultant force urges the portion of the swash
plate 25 adjacent to the non-restraining hinge element 70 to move
away from the lug plate 24, that is, urges the second guide surface
72 to move away from the first guide surface 71. However, the
surface of the swash plate 25 facing toward the lug plate 24
provides the receiving surface 25a which is located on the suction
side with respect to the first imaginary plane CP and on the side
of the bottom position B with respect to the second imaginary plane
SP. When the rotational speed of the drive shaft 16 is increased
(e.g. 4000 to 5000 rpm or more) and the swash plate 25 is inclined
at the maximum inclination angle, the receiving surface 25a is
pressed against the lug plate 24. Thus, the portion of the swash
plate 25 adjacent to the non-restraining hinge element 70, that is,
the upper right portion of the swash plate 25 with respect to the
line O2 shown in FIG. 4 is restrained from moving away from the lug
plate 24.
[0052] It is preferable that the receiving surface 25a should be
smaller as long as it is located within the above contactable
range. If the receiving surface 25a is formed in a large area, the
small area of the receiving surface 25a may actually contact with
the lug plate 24 due to the tolerance in assembling. In addition,
large area of the receiving surface 25a raises the production cost
due to high accurate machining.
[0053] In the compressor 10 of the preferred embodiment, the
receiving surface 25a is easily formed on the weight portion 25b of
the swash plate 25. This contributes to the reduction in the
production cost.
[0054] The receiving surface 25a is located at the position in the
range where it is contactable with the lug plate 24, which is
furthest from the axis O1 of the drive shaft 16, thus appropriately
receiving the force moving the swash plate 25 in the direction that
causes the first and second guide surfaces 71 and 72 to move away
from each other.
[0055] The compressor 10 of the preferred embodiment is adapted for
use in a vehicle, and the drive shaft 16 is constantly driven while
the engine of the vehicle is running. Thus, the compressor 10 often
operates under a small displacement. Accordingly, the compressor 10
enhances the reduction in noise and vibration, which is one of the
advantageous effects of the present invention.
[0056] In the compressor 10 of the preferred embodiment, the swash
plate 25 includes the elongated hole 22 with the parallel facing
surfaces 23 for receiving the outer circumferential surface of the
drive shaft 16. This reduces the production cost as compared to the
case where a sleeve is provided between the drive shaft 16 and the
swash plate 25. The parallel facing surfaces 23 of the elongated
hole 22 receive the part of the moment M that urges the swash plate
25 to turn around the line of intersection between the swash plate
25 and the first imaginary plane CP to be inclined relative to the
drive shaft 16 by the compression reactive force P1 and the suction
force P2. As described above, however, most of the moment M is
received by the restraining hinge element 60 and the
non-restraining hinge element 70. Thus, the parallel facing
surfaces 23 of the elongated hole 22 keeps a smooth contact with
the drive shaft 16, thereby suppressing the abrasion
therebetween.
[0057] Alternatively, a sleeve may be provided between the swash
plate 25 and the drive shaft 16. Like the hinge mechanism 26, the
sleeve supports the swash plate 25 so that it is inclinable
relative to the drive shaft 16 as disclosed in Japanese Patent
Application publication No. 6-123281. The sleeve is also slidable
relative to the outer circumferential surface of the drive shaft 16
in the axial direction of the drive shaft 16. The sleeve receives
the part of the moment M that urges the swash plate 25 to turn
around the line of intersection between the swash plate 25 and the
first imaginary plane CP.
[0058] Alternatively, the support arm 61 may be provided on the
swash plate 25, and the guide pin 62 may be provided on the lug
plate 24. The first guide surface 71 may be provided on the swash
plate 25, and the second guide surface 72 may be provided on the
lug plate 24.
[0059] The present examples and embodiments are to be considered as
illustrative and not restrictive, and the invention is not to be
limited to the details given herein but may be modified within the
scope of the appended claims.
* * * * *