U.S. patent application number 10/132283 was filed with the patent office on 2002-12-12 for fixed displacement compressors.
Invention is credited to Hasegawa, Yutaka, Sagiya, Masatoshi.
Application Number | 20020184999 10/132283 |
Document ID | / |
Family ID | 19012469 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020184999 |
Kind Code |
A1 |
Hasegawa, Yutaka ; et
al. |
December 12, 2002 |
Fixed displacement compressors
Abstract
A fixed displacement compressor includes a cylinder block having
a plurality of cylinder bores formed therethrough, a drive shaft
rotatably supported by the cylinder block, and a plate rotatably
mounted on the drive shaft. Moreover, an inclination angle of the
plate varies relative to a radial line perpendicular to the drive
shaft. The compressor also includes a spring positioned adjacent to
the plate. The spring is adapted to urge the plate in a direction
which reduces the inclination angle of the plate. In an embodiment,
the plate is a swash plate. In another embodiment, the compressor
further includes a cam rotor fixed to the drive shaft. In this
latter embodiment, the spring is positioned between the cam rotor
the plate.
Inventors: |
Hasegawa, Yutaka;
(Isesaki-shi, JP) ; Sagiya, Masatoshi;
(Isesaki-shi, JP) |
Correspondence
Address: |
BAKER BOTTS LLP
C/O INTELLECTUAL PROPERTY DEPARTMENT
THE WARNER, SUITE 1300
1299 PENNSYLVANIA AVE, NW
WASHINGTON
DC
20004-2400
US
|
Family ID: |
19012469 |
Appl. No.: |
10/132283 |
Filed: |
April 26, 2002 |
Current U.S.
Class: |
92/12.2 ;
417/269; 91/499 |
Current CPC
Class: |
F04B 27/18 20130101 |
Class at
Publication: |
92/12.2 ;
417/269; 91/499 |
International
Class: |
F01B 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2001 |
JP |
P2001-170571 |
Claims
What is claimed is:
1. A fixed displacement compressor comprising: a cylinder block
having a plurality of cylinder bores formed therethrough; a drive
shaft rotatably supported by said cylinder block; a plate rotatably
mounted on said drive shaft, wherein an inclination angle of said
plate varies relative to a radial line perpendicular to said drive
shaft; and at least one spring positioned adjacent to said plate,
wherein said spring is adapted to urge said plate in a direction
which reduces said inclination angle of said plate.
2. The compressor of claim 1, wherein said plate is a swash
plate.
3. The compressor of claim 1, wherein when said drive shaft is
engaged, said inclination angle increases from a minimum
inclination angle to a maximum inclination angle.
4. The compressor of claim 1, wherein when said drive shaft is
disengaged, said inclination angle deceases from a maximum
inclination angle to a minimum inclination angle.
5. The compressor of claim 1, further comprising a cam rotor fixed
to said drive shaft, wherein said at least one spring is positioned
between said cam rotor and said plate.
6. The compressor of claim 5, wherein said plate is a swash plate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates generally to fixed displacement
compressors used in automotive air conditioning systems. More
particularly, the invention relates to swash plate-type, fixed
displacement compressors used in automotive air conditioning
systems.
[0003] 2. Description of Related Art
[0004] A known swash plate-type, fixed displacement compressor may
comprise a cylinder block, a front housing, a valve plate, and a
cylinder head. The cylinder block may be substantially cylindrical
and also may be enclosed by the front housing and the cylinder
head. A crank chamber may be formed between the cylinder block and
the front housing. Moreover, a suction chamber and a discharge
chamber may be formed within the cylinder head and adjacent to the
valve plate. An inlet port and an outlet port may communicate with
the suction chamber and the discharge chamber, respectively, and
the inlet port and the outlet port may be connected to a
refrigerant circuit of an air conditioning system of a vehicle. The
cylinder block, the front housing, the valve plate, and the
cylinder head may be fixably attached to each other by a plurality
of bolts. Such known compressors also may comprise a plurality of
cylinder bores formed in the cylinder block. The cylinder bores may
be arranged radially with respect to a central axis of the cylinder
block.
[0005] Such known compressors further may comprise a drive shaft, a
cam rotor, a swash plate, a plurality of shoes, and a plurality of
pistons. The drive shaft may extend along a central axis of such
known compressors through the crank chamber, and also may be
rotatably supported by the front housing and the cylinder block via
a pair of bearings mounted in the front housing and the cylinder
block, respectively. Such known compressors also may comprise an
electromagnetic clutch. A drive belt may be used to engage the
electromagnetic clutch by transmitting a driving force from a
crankshaft of an engine of a vehicle to the electromagnetic clutch.
When the electromagnetic clutch is engaged, the driving force also
is transmitted from the electromagnetic clutch to the drive shaft.
Moreover, the cam rotor may be fixed to the drive shaft and may be
positioned within the crank chamber, and a slot may be formed
through the cam rotor. The swash plate also may be positioned
within the crank chamber and may be fixably mounted on the drive
shaft. The swash plate may comprise a pin member which may extend
toward the cam rotor. The pin member may be inserted into the slot
of the cam rotor.
[0006] Moreover, each piston may be positioned within a
corresponding cylinder bore, and the pistons may reciprocate
independently within their corresponding cylinder bore. Each of the
pistons also may be connected to the swash plate via a pair of
shoes. Specifically, each shoe may comprise a substantially flat
surface and a substantially semispherical portion. The flat surface
may be in slidable contact with the swash plate, and the
semispherical portion may rotatably engage a substantially
semispherical cavity of the piston. A plurality of suction ports
and a plurality of discharge ports may be formed through the valve
plate for each of the cylinder bores. A suction reed valve may be
positioned between the cylinder block and the valve plate. The
suction reed valve may open and may close the suction port in order
to control a flow of a refrigerant from the suction chamber to the
cylinder bores. A discharge reed valve may be positioned between
the valve plate and the cylinder head. The discharge reed valve may
open and may close the discharge port in order to control a flow of
the refrigerant from the cylinder bores to the discharge
chamber.
[0007] In operation, when the electromagnetic clutch and the drive
shaft are engaged, the driving force from the engine of the vehicle
is transmitted to the drive shaft, such that the drive shaft, the
cam rotor, and the swash plate rotate substantially simultaneously
about an axis of the drive shaft. Specifically, the rotational
movement of the drive shaft is transmitted to the cam rotor, and
the rotational movement of the cam rotor is transmitted to the
swash plate via a coupling mechanism comprising the slot and the
pin member, such that the swash plate moves back and forth in a
wobbling motion. Consequently, each piston reciprocates within its
corresponding bore. When the pistons reciprocate within their
corresponding cylinder bore, refrigerant gas introduced into the
suction chamber via the inlet port may be drawn into each cylinder
bore and subsequently may be compressed. When the refrigerant gas
is compressed, the discharge reed valve opens and the refrigerant
gas is discharged from the cylinder bores into the discharge
chamber. Moreover, the refrigerant gas is discharged from the
discharge chamber into the refrigerant circuit via the outlet
port.
[0008] In such known compressors, the electromagnetic clutch and
the drive shaft may be engaged or disengaged in order to control
the air conditioning system of the vehicle. Nevertheless, when the
operation of such known compressors begins, frictional forces may
exist between the swash plate and the shoes. Moreover, an initial
torque of the compressor may be such that the vehicle's speed may
decrease when the operation of such known compressors begins. Other
known compressors may include an electromagnetic clutch adapted to
absorb a greater initial torque than the known compressors
described above. However, such an electromagnetic clutch may
increase the weight of the vehicle, and also may increase the
manufacturing cost of the vehicle.
SUMMARY OF THE INVENTION
[0009] Therefore, a need has arisen for fixed displacement
compressors which overcome these and other shortcomings of the
related art. A technical advantage of the present invention is that
when a drive shaft is engaged, an inclination angle of a swash
plate initially may be at a minimum inclination angle, and may
increase to a maximum inclination angle. Consequently, an initial
frictional force between a swash plate and a shoe and an initial
torque of the compressor may be reduced relative to that of known
swash plate-type, fixed displacement compressors, as described
above. As such, a vehicle's speed may not decrease when the drive
shaft is engaged.
[0010] According to an embodiment of the present invention, a fixed
displacement compressor is described. The compressor comprises a
cylinder block having a plurality of cylinder bores formed
therethrough, a drive shaft rotatably supported by the cylinder
block, and a plate rotatably mounted on the drive shaft. Moreover,
an inclination angle of the plate varies relative to a radial line
perpendicular to the drive shaft. The compressor also comprises at
least one spring positioned adjacent to the plate. The at least one
spring is adapted to urge the plate in a direction which reduces
the inclination angle of the plate. In an embodiment, the plate is
a swash plate. In another embodiment, the compressor further
comprises a cam rotor fixed to the drive shaft. In this latter
embodiment, the at least one spring is positioned between the cam
rotor and the plate.
[0011] Other objects, features, and advantages of the present
invention will be apparent to persons of ordinary skill in the art
in view of the following detailed description of the invention and
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] For a more complete understanding of the present invention,
the needs satisfied thereby, and the objects, features, and
advantages thereof, reference now is made to the following
descriptions taken in connection with the accompanying
drawings.
[0013] FIG. 1 is a cross-sectional view of a swash plate-type,
fixed displacement compressor according to an embodiment of the
invention when a drive shaft is engaged.
[0014] FIG. 2 is a cross-sectional view of the swash plate-type,
fixed displacement compressor of FIG. 1 according to an embodiment
of the invention when the drive shaft is disengaged.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] Preferred embodiments of the present invention and their
advantages may be understood by referring to FIGS. 1 and 2, like
numerals being used for like corresponding parts in the various
drawings.
[0016] Referring to FIGS. 1 and 2, a swash plate-type, fixed
displacement compressor 100 according to an embodiment of the
present invention is depicted. Although the present invention is
described with respect to a swash plate-type, fixed displacement
compressor, it will be understood by those of ordinary skill in the
art that the present invention may be applied to swash plate-type,
fixed displacement compressors, wobble plate-type, fixed
displacement compressors, or the like. Compressor 100 may comprise
a cylinder block 2, a front housing 4, a valve plate 5, and a
cylinder head 8. Cylinder block 2 may be substantially cylindrical,
and also may be enclosed by front housing 4 and cylinder head 8. A
crank chamber 3 may be formed between cylinder block 2 and front
housing 4. Moreover, a suction chamber 6 and a discharge chamber 7
may be formed within cylinder head 8 and adjacent to valve plate 5.
An inlet port (not shown) and an outlet port (not shown) may
communicate with suction chamber 6 and discharge chamber 7,
respectively, and the inlet port and the outlet port may be
connected to a refrigerant circuit (not shown) of an air
conditioning system of a vehicle. Cylinder block 2, front housing
4, valve plate 5, and cylinder head 8 may be fixably attached to
each other by a plurality of bolts 50. Compressor 100 also may
comprise a plurality of cylinder bores 1 formed in cylinder block
2. Cylinder bores 1 may be arranged radially with respect to a
central axis of cylinder block 2.
[0017] Compressor 100 further may comprise a drive shaft 9, a cam
rotor 10, a swash plate 11, a plurality of shoes 13, and a
plurality of pistons 14. Drive shaft 9 may extend along a central
axis of compressor 100 through crank chamber 3 and also may be
rotatably supported by front housing 4 and cylinder block 2 via a
pair of bearings 20a and 20b mounted in front housing 4 and
cylinder block 2, respectively. Compressor 100 also may comprise an
electromagnetic clutch (not shown). A drive belt (not shown) may be
used to engage the electromagnetic clutch by transmitting a driving
force from a crankshaft of an engine of a vehicle (not shown) to
the electromagnetic clutch. When the electromagnetic clutch is
engaged, the driving force also is transmitted from the
electromagnetic clutch to drive shaft 9. Moreover, cam rotor 10 may
be fixed to drive shaft 9 and may be positioned within crank
chamber 3, and a slot 10a may be formed through cam rotor 10. Swash
plate 11 also may be positioned within crank chamber 3, and may be
slidably mounted on drive shaft 9, such that an inclination angle
.theta. of swash plate 11 may vary relative to a line which is
perpendicular to drive shaft 9. Swash plate 11 may comprise a pin
member 11a which may extend toward cam rotor 10. Pin member 11a may
be inserted into slot 10a of cam rotor 10, and a coil spring 12 may
urge swash plate 11 away from cam rotor 10. Specifically, coil
spring 12 may engage drive shaft 9 and may be positioned between
cam rotor 10 and swash plate 11, such that coil spring 12 urges
swash plate 11 to move in a direction which reduces inclination
angle .theta. of swash plate 11.
[0018] Moreover, each piston 14 may be positioned within a
corresponding cylinder bore 1, and pistons 14 may reciprocate
independently within a corresponding cylinder bore 1. Each piston
14 also may be connected to swash plate 11 via a pair of shoes 13.
Specifically, each shoe 13 may comprise a substantially flat
surface and a substantially semispherical portion. The flat surface
may be in slidable contact with swash plate 11, and the
semispherical portion may rotatably engage a substantially
semispherical cavity of piston 14.
[0019] A plurality of suction ports 15 and plurality of discharge
ports 16 may be formed through valve plate 5 for each cylinder bore
1. A suction reed valve 15a may be positioned between cylinder
block 2 and valve plate 5. Suction reed valve 15a may open and may
close suction port 15 in order to control a flow of a refrigerant
from suction chamber 6 to cylinder bores 1. A discharge reed valve
16a may be positioned between valve plate 5 and cylinder head 8.
Discharge reed valve 16a may open and may close discharge port 16
in order to control a flow of the refrigerant from cylinder bores 1
to discharge chamber 7.
[0020] In operation, when the electromagnetic clutch and drive
shaft 9 are engaged, the driving force from the engine of the
vehicle is transmitted to drive shaft 9, such that drive shaft 9,
cam rotor 10, and swash plate 11 rotate substantially
simultaneously about an axis of drive shaft 9. Specifically, the
rotational movement of drive shaft 9 is transmitted to cam rotor
10, and the rotational movement of cam rotor 10 is transmitted to
swash plate 11 via a coupling mechanism comprising slot 10a and pin
member 11a, such that swash plate 11 moves back and forth in a
wobbling motion. Consequently, each piston 14 reciprocates within
its corresponding bore 1. When pistons 14 reciprocate within their
corresponding cylinder bore 1, refrigerant gas introduced into
suction chamber 6 via the inlet port may be drawn into each
cylinder bore 1 and subsequently is compressed. When the
refrigerant gas is compressed, discharge reed valve 16a opens and
the refrigerant gas is discharged from cylinder bores 1 into
discharge chamber 7. Moreover, the refrigerant gas then is
discharged from discharge chamber 7 into the refrigerant circuit
via the outlet port.
[0021] During operation, a compressive force is applied to pistons
14, and pistons 14 may apply a first force M1 on swash plate 11.
First force M1 may be a force which is adapted to turn pin member
11a in a clockwise direction, such that first force M1 may urge
swash plate 11 in a direction, which increases inclination angle
.theta. of swash plate 11. Moreover, coil spring 12 may apply a
second force M2 on swash plate 11. Second force M2 may be a force
which is adapted to turn pin member 11a in a counterclockwise
direction, such that second force M2 may urge swash plate 11 in a
direction which decreases inclination angle .theta. of swash plate
11. Nevertheless, during operation of compressor 100, first force
M1 may be greater than second force M2. Consequently, as shown in
FIG. 1, during operation, inclination angle .theta. of swash plate
11 may increase to a maximum inclination angle, and a stroke of
each piston 14 also may increase to a maximum piston stroke. In
contrast, as shown in FIG. 2, when compressor 100 is not in
operation, first force M1 may be zero, such that only second force
M2 may act on swash plate 11. Consequently, inclination angle
.theta. of swash plate 11 may decrease to a minimum inclination
angle, and the stroke of each piston 14 may decrease to a minimum
piston stroke.
[0022] When drive shaft 9 is engaged, because inclination angle
.theta. of swash plate 11 initially may be at the minimum
inclination angle, an initial frictional force between swash plate
11 and shoes 13 and an initial torque of compressor 100 each may be
reduced relative to known swash plate-type, fixed displacement
compressors. As such, the vehicle's speed may not decrease when
drive shaft 9 is engaged. Moreover, after drive shaft 9 is engaged,
first force M1 may increase and may become greater than second
force M2, such that inclination angle .theta. of swash plate 11
increases until inclination angle .theta. of swash plate 11 reaches
the maximum inclination angle.
[0023] While the invention has been described in connection with
preferred embodiments, it will be understood by those of ordinary
skill in the art that other variations and modifications of the
preferred embodiments described above may be made without departing
from the scope of the invention. Other embodiments will be apparent
to those of ordinary skill in the art from a consideration of the
specification or practice of the invention disclosed herein.
* * * * *