U.S. patent application number 09/829577 was filed with the patent office on 2001-10-11 for variable displacement compressors.
Invention is credited to Fukutani, Yoshikazu, Inaji, Satoshi, Ishigaki, Yoshinobu, Kawai, Toshihiro, Kawakami, Motonobu, Ota, Masaki.
Application Number | 20010028851 09/829577 |
Document ID | / |
Family ID | 18622478 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010028851 |
Kind Code |
A1 |
Ota, Masaki ; et
al. |
October 11, 2001 |
Variable displacement compressors
Abstract
A variable displacement compressor 10 includes return springs 9
and 19 that press a swash plate 11 in the axial direction of a
drive shaft 8. One end of the return spring 19 is fastened to the
swash plate 11, and the other end is fastened to a ring-like
(toric) receiving plate 19a through which the drive shaft 8 is
inserted. When the swash plate 11 rotates, the return spring 19 and
the receiving plate 19a rotate in synchronism with the swash plate
11, and the receiving plate 19a slides in contact with a contact
portion 1a of the cylinder block 1.
Inventors: |
Ota, Masaki; (Kariya-shi,
JP) ; Kawai, Toshihiro; (Kariya-shi, JP) ;
Ishigaki, Yoshinobu; (Kariya-shi, JP) ; Inaji,
Satoshi; (Kariya-shi, JP) ; Kawakami, Motonobu;
(Kariya-shi, JP) ; Fukutani, Yoshikazu;
(Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
345 Park Avenue
New York
NY
10154
US
|
Family ID: |
18622478 |
Appl. No.: |
09/829577 |
Filed: |
April 10, 2001 |
Current U.S.
Class: |
417/269 |
Current CPC
Class: |
F04B 27/1063
20130101 |
Class at
Publication: |
417/269 |
International
Class: |
F04B 001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 11, 2000 |
JP |
2000-109863 |
Claims
1. A variable displacement compressor comprising: a drive shaft, a
support member supporting the drive shaft, a swash plate that
rotates in synchronism with the drive shaft, a piston that is
disposed within a cylinder bore, wherein the rotation of the swash
plate is converted into the reciprocation of the piston, and the
stroke length of the piston and the discharge capacity of the
compressor change in accordance with the inclination angle of the
swash plate, a return spring provided on the circumference of the
drive shaft between the swash plate and the support member, the
return spring urging the swash plate, and a receiving portion
receiving an end of the return spring in contact with a contact
portion of the support member between the return spring and the
support member.
2. A variable displacement compressor according to claim 1, wherein
the contact portion is formed on the support member itself.
3. A variable displacement compressor according to claim 1, wherein
the receiving portion is fastened to the return spring.
4. A variable displacement compressor according to claims 1,
wherein the receiving portion substantially has a ring shape.
5. A variable displacement compressor according to claim 1, wherein
the receiving portion is integrally formed with the contact
portion.
6. A variable displacement compressor according to claim 5, wherein
the receiving portion has been hardened.
7. A variable displacement compressor having a support member that
supports a drive shaft, a swash plate that rotates in synchronism
with the drive shaft, a piston that is disposed within a cylinder
bore, wherein the rotation of the swash plate is converted into the
reciprocation of the piston, and the stroke length of the piston
and the discharge capacity of the compressor change in accordance
with the inclination angle of the swash plate, further comprising:
a return spring provided on the circumference of the drive shaft
between the swash plate and the support member, the return spring
urging the swash plate, and means for receiving an end of the
return spring in contact with a contact portion of the support
member between the return spring and the support member.
8. A variable displacement compressor according to claim 7, wherein
the contact portion is formed on the support member itself.
9. A variable displacement compressor according to claim 7, wherein
the means for receiving the end of the return spring is fastened to
the return spring.
10. A variable displacement compressor according to claim 7,
wherein the means for receiving the end of the return spring is
formed in a ring-like shape.
11. A variable displacement compressor according to claim 7,
wherein the means for receiving the end of the return spring is
integrally formed with the contact portion.
12. A variable displacement compressor according to claim 11,
wherein the means for receiving the end of the return spring has
been hardened.
13. A method for manufacturing the variable displacement compressor
according to claim 1 comprising: providing a return spring urging
the swash plate on the circumference of the drive shaft between the
swash plate and the support member and providing a receiving
portion that receives the end of the return spring in contact with
a contact portion of the support member between the return spring
and the support member.
14. A method as in claim 13, further comprising forming the contact
portion on the support member itself.
15. A method as in claim 13, further comprising fastening the
receiving portion to the return spring.
16. A method as in claim 13, further comprising forming the
receiving portion into a substantially ring shape.
17. A method as in claim 13, further comprising integrally forming
the receiving portion with the contact portion.
18. A method as in claim 17, further comprising hardening the
receiving portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to variable displacement
compressors that may preferably be used in automotive air
conditioning systems and other devices.
[0003] 2. Description of Related Art
[0004] As one type of known compressors, a variable displacement
compressor is disclosed in Japanese unexamined patent specification
No.2000-2180 and is typically used in automotive air conditioning
systems. The variable displacement compressor changes the
compressor output discharge capacity by changing the pressure
within a crank chamber that includes a swash plate. The swash plate
is coupled to a drive shaft and rotates together with the drive
shaft. The swash plate changes the inclination angle with respect
to the plane perpendicular to the axis of the drive shaft. A return
spring is disposed around the circumference of the drive shaft near
the swash plate. The return spring urges the swash plate in the
axial direction of the drive shaft and holds the swash plate in a
set position (e.g., a position slightly inclined relative to the
plane perpendicular to the axis of the drive shaft) while the
compressor is not operating. The drive shaft includes a ring groove
on the axial circumference of the drive shaft. A ring-shaped
circular clip (fastener) fastened in the ring groove serves as a
receiving portion for receiving the end of the return spring.
[0005] In such compressors, a ring groove must be formed in order
to fasten the circular clip to the drive shaft. Moreover, in
automated assembly conditions, confirmation process is necessary to
determine whether or not the machinery has accurately inserted the
circular clip into the ring groove.
SUMMARY OF THE INVENTION
[0006] It is, therefore, an object of the present invention to
provide improved variable displacement compressors.
[0007] In one aspect of the present teachings, the variable
displacement compressor includes a return spring having a
simplified receiving construction.
[0008] In general, the variable displacement compressor includes a
drive shaft, a support member, a swash plate, a piston, a return
spring, and a receiving portion. The support member supports the
drive shaft. The swash plate rotates in synchronism with the drive
shaft. The piston is disposed within a cylinder bore. The rotation
of the swash plate is converted into the reciprocation of the
piston. The stroke length of the piston and the discharge capacity
of the compressor changes in accordance with the inclination angle
of the swash plate. The return spring is provided on the
circumference of the drive shaft between the swash plate and the
support member. The return spring urges the swash plate. The
receiving portion receives an end of the return spring in contact
with a contact portion of the support member between the return
spring and the support member. A mechanism for fastening the
receiving portion that receives the return spring is therefore not
required. As the result, the return spring may have a simplified
receiving construction.
[0009] Preferably, the contact portion may be formed on the support
member itself. Such a configuration does not require an additional
member with a contact portion and allows the contact mechanism of
the receiving portion to be simplified.
[0010] In another preferred aspect of the present teachings, the
receiving portion may be fastened to the return spring. This allows
the return spring and the receiving portion to rotate
simultaneously together with the rotation of the swash plate.
Localized wearing of the receiving portion by the end of the return
spring contacting the receiving portion is thereby prevented.
[0011] In another aspect, the receiving portion may have a
ring-like shape. Forming the receiving portion in a ring-like shape
corresponding to the exterior shape of the drive shaft allows the
receiving portion to be easily attached by inserting the drive
shaft in the receiving portion. The pushing action of the return
spring allows the receiving portion to secure itself in its
designated position.
[0012] The receiving portion may be formed integrally with the
contact portion of the support member, which allows for a reduction
in the number of parts needed to receive the end of the return
spring.
[0013] Preferably, the receiving portion is hardened. If aluminum
is utilized to reduce weight, the support member is made of an
aluminum alloy. Therefore, when the return spring made of hardened
steel is received, the support member may be damaged. However, by
hardening the receiving portion, the receiving portion by the end
of the return spring contacting the receiving portion is prevented
from being worn.
[0014] Additional objects, features and advantages of the present
invention will be readily understood after reading the following
detailed description together with the accompanying drawings and
the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows a variable displacement compressor according to
one of the embodiments.
[0016] FIG. 2 shows an expanded view of the area indicated by
broken line A shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Compressors include, for example, a support member that
supports a drive shaft. A swash plate is provided to rotate in
synchronism with the drive shaft and the rotation of the swash
plate is converted into reciprocation of a piston within a cylinder
bore. The stroke length of the piston and the compressor output
discharge capacity of a fluid (refrigerant) change when the
inclination angle of the swash plate changes.
[0018] In addition or in the alternative, compressors include a
return spring that is provided on the circumference of the drive
shaft between the swash plate and the support member. Preferably,
the return spring urges or biases the swash plate. In addition or
in the alternative, a receiving portion is provided to receive the
end of the return spring in contact with a contact portion of the
support member between the return spring and the support
member.
[0019] In other embodiments, the compressor may include means for
receiving the end of the return spring in contact with a contact
portion of the support member between the return spring and the
support member. In other compressors, the contact portion may be
formed on the support member itself. Moreover, the receiving
portion may be fastened to the return spring. The receiving portion
may optionally have a ring-like shape. Further, the receiving
portion is integrally formed with the contact portion. Preferably,
the receiving portion has been hardened.
[0020] Methods for manufacturing such compressors are taught. For
example, a return spring is provided to urge or bias the swash
plate along the axis of the drive shaft and on the circumference of
the drive shaft between the swash plate and the support member. In
addition, a receiving portion is provided to receive the end of the
return spring in contact with a contact portion of the support
member between the return spring and the support member.
[0021] Additional examples of the present teachings will be
described in greater detail with reference to the attached
drawings. This detailed description is merely intended to teach a
person of skill in the art further details for practicing preferred
aspects of the present teachings and is not intended to limit the
scope of the invention. Only the claims define the scope of the
claimed invention. Therefore, combinations of features and steps
disclosed in the above detail description may not be necessary to
practice the invention in the broadest sense, and are instead
taught merely to particularly describe some examples of the
invention. In addition, the present teachings naturally may be
combined in ways that are not specifically enumerated in order to
provide additional useful embodiments of the present teachings.
[0022] As detailed examples of the compressors, a variable
displacement compressor will now be described with reference to
FIGS. 1 and 2. In this detailed embodiment, an explanation will be
presented of a compressor for an automotive air conditioning system
that draws a refrigerant, compresses the refrigerant to a higher
pressure, and discharges the high pressure refrigerant. While the
present detailed embodiment is taught in terms of a refrigerant,
naturally the present compressors are utilized with other
fluids.
[0023] As shown in FIG. 1, as one example of the compressor, a
variable displacement compressor 10 (hereinafter referred to as
"compressor") includes a cylinder block 1, a front housing 2 fixed
to the front end (on the left side of the figure) of the cylinder
block 1, and a rear housing 5 fixed via a valve plate 6 to the rear
end (on the right side of the figure) of the cylinder block 1. The
rear housing 5 includes a suction chamber 3 for a refrigerant
before compression and a discharge chamber 4 for the compressed
refrigerant. Suction valves 27, discharge valves 29, and valve
retainers 30 are attached to the valve plate 6 by a fastener 31.
The valve plate 6 comprises suction ports 26 that connects the
suction chamber 3 and cylinder bores 14 via the respective suction
valves 27 and discharge ports 28 that connects the discharge
chamber 4 and the cylinder bores 14 via the respective discharge
valves 29.
[0024] A drive shaft 8 transmits rotation from a drive source to a
swash plate 11 and is inserted through the cylinder block 1 and the
front housing 2. The drive shaft 8 is rotatably supported within
the cylinder block 1, which functions as a support member. A thrust
race 32 and a spring member 33 adapted to urge or bias the rear end
of the drive shaft 8 forward (toward the side of the front housing
2) are disposed in the cylinder block 1 on the side of the rear
housing 5. The elastic urging force of the spring member 33 is
received by a thrust bearing 34 disposed between a rotor 12 and the
front housing 2.
[0025] A disk-like swash plate 11 is disposed within a crank
chamber 7 defined in the front housing 2. The swash plate 11 is
coupled to the drive shaft 8 and rotates together with the drive
shaft 8. The swash plate 11 is supported on the drive shaft 8
slidably in the axial direction and inclinably with respect to the
drive shaft 8. The rotor 12 is fastened to the drive shaft 8. The
rotor 12 rotates integrally with the swash plate 11 via a hinge
mechanism 13 to transmit the rotation of the drive shaft 8 to the
swash plate 11. The rotor 12 allows the swash plate 11 to rotate at
various inclination angles.
[0026] Return springs 9 and 19 apply pressure to the swash plate 11
in the axial direction of the drive shaft 8 and are located on the
circumference of the drive shaft 8 near the swash plate 11 (on the
left and right sides of FIG. 1). The ends of the return spring 9
are respectively received by the swash plate 11 and the rotor 12.
The ends of the return spring 19 are received by the swash plate 11
and a receiving plate 19a. The receiving plate 19a is supported in
contact with the cylinder block 1. As a result of the balance
between the return springs 9 and 19, the swash plate 11 is held in
a designated position (e.g., a position slightly inclined relative
to the plane perpendicular to the axis of the drive shaft 8) when
the compressor 10 is not operating. The receiving plate 19a
functions as a receiving portion or receiving means as utilized
herein.
[0027] A detailed description of the portion of the compressor
proximal to the return spring 19 and the receiving plate 19a will
be provided with reference to FIG. 2. As shown in FIG. 2, the
receiving plate 19a has a ring-like (toric) shape with an insertion
hole 19b corresponding to the exterior shape of the drive shaft 8.
The receiving plate 19a is therefore attached by inserting the
drive shaft 8 into the receiving plate 19a. One end of the return
spring 19 is fastened to the swash plate 11 and the other end is
fastened to the receiving plate 19a inserted into the drive shaft
8. The receiving plate 19a is urged in the direction away from the
swash plate 11 (the direction of arrow 40 in FIG. 2). Therefore,
the return spring 19 and the receiving plate 19a rotate in
synchronism with the swash plate 11 when the swash plate 11
rotates. In this case, the receiving plate 19a slides in contact
with a contact portion 1a of the cylinder block 1 on the opposite
side of the swash plate 11 against the return spring 19.
[0028] A plurality of cylinder bores 14 is arranged using any
preferred circumferentially spacing around the cylinder block 1. A
piston 15 is slidably disposed within each cylinder bore 14. The
rear face of each piston 15 is connected to the swash plate 11 via
a pair of shoes 16 to convert the rotation of the swash plate 11
into the reciprocating movement of the piston 15. Therefore, when
the swash plate 11 rotates together with the rotation of the drive
shaft 8, each piston 15 reciprocates within its respective cylinder
bore 14 together with the rotational movement. The reciprocating
pistons 15 cause, for example, the refrigerant to be drawn from the
suction chamber 3 into the cylinder bore 14 (i.e. a suction
stroke). Thereafter, a compressed refrigerant is discharged from
the cylinder bore 14 to the discharge chamber 4 after compression
(i.e. a discharge stroke).
[0029] The output discharge capacity of the compressor 10 is
determined according to the stroke length (the distance from the
upper dead point to the lower dead point) of the piston 15. The
stroke length of the piston 15 is determined by the inclination
angle of the swash plate 11 with respect to a plane perpendicular
to the axis of the drive shaft 8. More specifically, the stroke
length of the pistons 15 and discharge capacity of the compressor
10 increase as the inclination angle of the swash plate 11
increases. On the other hand, the stroke length of the pistons 15
and discharge capacity of the compressor 10 decrease as the
inclination angle of the swash plate 11 decreases. The inclination
angle of the swash plate 11 during operation of the compressor is
determined by the differential pressure between the inside of the
cylinder bores 14 and the inside of the crank chamber 7. The
differential pressure can be adjusted, for example, by releasing
the compressed high-pressure refrigerant into the crank chamber 7
by means of a capacity control valve (not shown).
[0030] In the variable displacement compressor 10, the receiving
plate 19a can receive the return spring 19 in contact with the
contact portion 1a of the cylinder block 1 that supports the drive
shaft 8. Thus, it is not necessary to fasten the receiving plate
19a that receives the return spring 19. For example, it is not
necessary to fasten the receiving plate 19a to the drive shaft 8
and processing steps to fasten the drive shaft 8 to the receiving
plate 19a can be eliminated. Therefore, the receiving structure of
the return spring is simplified by virtue of the receiving plate
19a.
[0031] The contact portion 1a is provided on the cylinder block 1
in order to simplify the contact construction of the receiving
plate 19a. Further, the receiving plate 19a is fastened to the
return spring 19, so the receiving plate 19a is prevented as much
as possible from being locally worn by the end of the return spring
19 when the return spring 19 has rotated. Moreover, the receiving
plate 19a is formed as a ring-like (toric) shape corresponding to
the exterior shape of the drive shaft 8, so the attachment of the
receiving plate 19a is simple.
[0032] Naturally, variety of modifications are made to the above
described embodiments without departing from the spirit of the
invention. For example, while a ring-shaped (toric) receiving plate
19a that contacts the contact portion 1a of the cylinder block 1
was described above, the receiving plate 19a may have a variety of
shapes, sizes, or other features.
[0033] In addition, various modifications are possible according to
the mutual shapes in an embodiment in which the receiving plate 19a
contacts the contact portion 1a of the cylinder block 1. For
example, a recess may be formed in the contact portion 1a of the
cylinder block 1 so that the receiving plate 19a fits into the
recess. In the alternative, a protrusion corresponding to the size
of the receiving plate 19a may be formed on the contact portion 1a
of the cylinder block 1 so that the receiving plate 19a makes
contact with the protrusion. Moreover, the contact portion need not
be present on the cylinder block 1 itself, and may instead be
present on a separate member attached to the cylinder block 1.
[0034] In the description of the above embodiments, the cylinder
block 1 may include a separate receiving plate 19a. However, the
location corresponding to receiving plate 19a is also established
integrally on the contact portion 1a of the cylinder block 1. At
such a time, hardening the location that receives the end of the
return spring 19 substantially prevent the wearing of the location
corresponding to the receiving plate by the contact portion 1a of
the cylinder block 1.
* * * * *