U.S. patent application number 14/246282 was filed with the patent office on 2015-10-08 for seal structure for a rotary valve compressor.
The applicant listed for this patent is Halla Visteon Climate Control Corp.. Invention is credited to Michael Gregory Theodore, JR..
Application Number | 20150285230 14/246282 |
Document ID | / |
Family ID | 54209364 |
Filed Date | 2015-10-08 |
United States Patent
Application |
20150285230 |
Kind Code |
A1 |
Theodore, JR.; Michael
Gregory |
October 8, 2015 |
SEAL STRUCTURE FOR A ROTARY VALVE COMPRESSOR
Abstract
A variable displacement compressor includes a rotary valve
coupled to a drive shaft of the compressor and configured to
selectively permit fluid communication between a suction chamber
and cylinders of the compressor. An annular seal is disposed
adjacent the rotary valve and engages at least a portion of a wall
defining the suction chamber and a surface of the rotary valve.
Inventors: |
Theodore, JR.; Michael Gregory;
(Plymouth, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halla Visteon Climate Control Corp. |
Daejeon |
|
KR |
|
|
Family ID: |
54209364 |
Appl. No.: |
14/246282 |
Filed: |
April 7, 2014 |
Current U.S.
Class: |
417/516 ;
251/314 |
Current CPC
Class: |
F04B 27/1009 20130101;
F04B 27/1063 20130101; F04B 27/1054 20130101; F04B 27/1018
20130101 |
International
Class: |
F04B 7/00 20060101
F04B007/00 |
Claims
1. A rotary valve assembly for controlling a supply of refrigerant
gas to cylinders in a variable displacement compressor, the rotary
valve assembly comprising: a rotary valve configured to selectively
permit fluid communication between a suction chamber and cylinders
of the compressor; and an annular seal disposed adjacent the rotary
valve and having a diameter corresponding to a diameter of the
rotary valve.
2. The rotary valve assembly of claim 1, wherein the seal has a
substantially rectangular cross-sectional shape.
3. The rotary valve assembly claim 1, wherein the seal has an outer
surface, the outer surface having a bevel formed therein, wherein
the bevel has a bevel angle of about 70 degrees.
4. The rotary valve assembly claim 1, further comprising an urging
member disposed adjacent the seal and configured to urge the seal
towards the rotary valve.
5. The rotary valve assembly claim 1, further comprising at least
one position tab extending laterally outwardly from an outer
surfaee of the seal.
6. The rotary valve assembly claim 5, wherein the position tab has
a shape corresponding to a shape of a recess formed in a wall
forming the suction chamber of the compressor.
7. The rotary valve assembly of claim 1, wherein the seal is formed
from a PEEK material.
8. A variable displacement compressor, comprising: a cylinder block
having a plurality of cylinders annularly formed therein and a
centrally formed aperture, a plurality of pistons received within
the cylinders; a rear head disposed adjacent one end of the
cylinder block, the rear head having a wall defining a suction
chamber; a crank case forming a crank chamber adjacent an other end
of the cylinder block; a drive shaft rotatably received in the
aperture of the cylinder block and extending through the crank
chamber; a swash plate assembly rotatably coupled to the drive
shaft, the swash plate assembly operably coupled to the pistons to
cause a reciprocating motion thereof; a rotary valve coupled to the
drive shaft and configured to selectively permit fluid
communication between the suction chamber of the rear head and the
cylinders of the cylinder block; and a seal disposed adjacent the
rotary valve and engaging at least a portion of the wall defining
the suction chamber.
9. The variable displacement compressor of claim 8, wherein the
seal engages a surface of the rotary valve.
10. The variable displacement compressor of claim 8, wherein the
wall defining the suction chamber urges the seal towards the rotary
valve.
11. The variable displacement compressor of claim 8, further
comprising an urging member disposed adjacent the seal and
configured to urge the seal towards the rotary valve, wherein the
urging member is one of an o-ring, a spring, and a pressurized
gas.
12. The variable displacement compressor of claim 8, wherein the
seal has a substantially annular body and a diameter substantially
equal to a diameter of an outer surface of the rotary valve.
13. The variable displacement compressor of claim 12, wherein the
annular body has a substantially rectangular cross-sectional
shape.
14. The variable displacement compressor of claim 8, wherein the
seal includes an outer surface having a bevel formed therein, the
bevel engaging the wall forming the suction chamber.
15. The variable displacement compressor of claim 14, wherein the
bevel has a bevel angle about 70 degrees.
16. The variable displacement compressor of claim 8, further
comprising at least one position tab extending laterally outwardly
from an outer surface of the seal.
17. The variable displacement compressor of claim 16, wherein the
position tab cooperates with the wall forming the suction chamber
to militate against a rotational movement of the seal.
18. The variable displacement compressor of claim 8, wherein the
seal is formed from a PEEK material.
19. The variable displacement compressor of claim 8, wherein the
seal is configured to seal a compressed refrigerant gas path formed
intermediate the rotary valve and the wall forming the suction
chamber.
20. A variable displacement compressor, comprising: a cylinder
block having a plurality of cylinders annularly formed therein and
a centrally formed aperture, a plurality of pistons received within
the cylinders; a rear head disposed adjacent one end of the
cylinder block, the rear head having a wall defining a suction
chamber; a crank case forming a crank chamber adjacent an other end
of the cylinder block; a drive shaft rotatably received in the
aperture of the cylinder block and extending through the crank
chamber; a swash plate assembly rotatably coupled to the drive
shaft, the swash plate assembly operably coupled to the pistons to
cause a reciprocating motion thereof; a rotary valve coupled to the
drive shaft and configured to selectively permit fluid
communication between the suction chamber of the rear head and the
cylinders of the cylinder block; and a seal disposed adjacent the
rotary valve and having a bevel formed on an outer surface thereof,
the bevel engaging the wall of the rear head forming the suction
chamber.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a variable displacement
compressor for use in an air conditioning system for a vehicle, and
more particularly to a seal structure for a variable displacement
compressor having a rotary valve for supplying a refrigerant gas
into a cylinder to be compressed.
BACKGROUND OF THE INVENTION
[0002] As commonly known, variable displacement compressors having
a swash plate are used in air conditioning systems of motor
vehicles. Such compressors typically include at least one piston
disposed in a cylinder of a cylinder block and a rotor assembly
operatively coupled to a drive shaft. The swash plate is coupled to
and caused to rotate by the rotor assembly. The swash plate is
variably angled relative to the rotor between a minimum angle and a
maximum angle. Each piston slidably engages with the swash plate
through a shoe as the swash plate rotates causing the piston to
reciprocate within the cylinder. As the angle of the swash plate
relative to the rotor varies, the stroke of each piston is varied
and, therefore, the total displacement or capacity of the
compressor is varied.
[0003] In variable displacement compressors having a swash plate,
reciprocation of the pistons within the cylinders results in each
of the pistons executing a suction stroke or a compression stroke.
During the suction stroke, a refrigerant gas is delivered from a
suction chamber of the compressor to the cylinder through a suction
port. During the compression stroke, the refrigerant gas is
compressed and delivered into a discharge chamber of the compressor
through a discharge port. The compressor typically includes a
suction reed valve and a discharge reed valve, wherein during the
suction stroke the suction reed valve is open and the discharge
reed valve is closed and during the compression stroke the suction
reed valve is closed and the discharge reed valve is open.
[0004] However, certain disadvantages are encountered with the use
of reed valves. For example, the reed valves are typically in a
normally closed configuration and require a sufficient pressure
differential to overcome a spring force thereof to effectively
open. Specifically, the suction reed cannot open properly unless a
pressure difference between the cylinder and the suction chamber is
sufficient to overcome the spring force thereof. Moreover, oil in
the compressor can cause the reed valves to stick. As a result, an
opening of the reed valve is delayed, an efficiency of the
compressor is minimized, and pressure pulsations which result in an
undesirable noise vibration harshness (NVH) are maximized.
Additionally, due to a geometry and a maximum bending stress of the
reed valves, the flow area of the refrigerant gas through the
suction port and discharge port is limited. Furthermore, because
the reed valves often do not open or close properly due to at least
the above reasons, the reed valves begin to "float." Floating
causes improper sealing and internal leakage.
[0005] To overcome some of these deficiencies, a rotary valve has
been included in variable displacement compressors to replace the
reed valves. For example, in U.S. Pat. No. 6,675,607 to Tarutani et
al., a variable displacement compressor with a swash plate using a
rotary valve for supplying a refrigerant gas into a gas compression
chamber is disclosed. The rotary valve is formed at a rear end
portion of a shaft and integrally formed with the shaft. The rotary
valve integrally rotates with the shaft as the shaft is rotated. A
suction port communicating with a bleeding channel of the shaft is
formed in the rotary valve. Suction channels of cylinder bores
communicate with the suction port in succession according to the
rotation of the shaft and the rotary valve. The suction channels
are formed inside the cylinder block and communicate with the
cylinder bores via a side wall forming the cylinder bore.
[0006] Additionally, in U.S. Pat. No. 5,562,425 to Kimura et al., a
rotary valve for use in piston type compressor is disclosed. The
rotary valve is retained in a valve chamber formed in a central
portion of a rear housing. The valve chamber communicates with a
suction chamber. The rotary valve includes a slot formed in a
central portion of the rotary valve in which a drive shaft engages
with to transmit rotation to the rotary valve. A suction passage
having an inlet and outlet is formed in the rotary valve.
[0007] However, these valve structures do not provide a maximum
suction flow of the refrigerant gas and/or provide an increase in a
dead volume ratio when the compressor is in a variable displacement
mode. Additional disadvantages include poor sealing of and
undesired leakage of the refrigerant gas to undesired areas of the
compressor. Furthermore, the rotary valve structures do not provide
desired thermal properties, durability, balance, and bearing
properties to minimize deflections thereof and operatively maintain
desired efficiency of the compressor.
[0008] Therefore, there is a continuing need for a rotary valve
structure that maintains a maximum suction flow of refrigerant gas
while minimizing a dead volume ratio of the compressor.
Additionally, there is a continuing need for a rotary valve
structure having desired thermal properties, durability, balance,
sealing properties and features, to operatively maintain a desired
efficiency of the compressor.
SUMMARY OF THE INVENTION
[0009] Concordant and congruous with the present invention, a
rotary valve structure that maintains a maximum suction flow of
refrigerant gas while minimizing a dead volume ratio of the
compressor, while also having desired thermal properties,
durability, balance, sealing properties and features, to
operatively maintain a desired efficiency of the compressor has
surprisingly been discovered.
[0010] According to an embodiment of the invention, a rotary valve
assembly for controlling a supply of refrigerant gas to cylinders
in a variable displacement compressor is disclosed. The rotary
valve assembly includes a rotary valve configured to selectively
permit fluid communication between a suction chamber and cylinders
of the compressor. An annular seal is disposed adjacent the rotary
valve and having a diameter corresponding to a diameter of the
rotary valve.
[0011] According to another embodiment of the invention, a variable
displacement compressor is disclosed including a cylinder block
having a plurality of cylinders annularly formed therein and a
centrally formed aperture. A plurality of pistons are received
within the cylinders. A rear head is disposed adjacent one end of
the cylinder block. The rear head has a wall defining a suction
chamber. A crank case forms a crank chamber adjacent an other end
of the cylinder block. A drive shaft is rotatably received in the
aperture of the cylinder block and extends through the crank
chamber. A swash plate assembly is rotatably coupled to the drive
shaft. The swash plate assembly is operably coupled to the pistons
to cause a reciprocating motion thereof. A rotary valve is coupled
to the drive shaft and configured to selectively permit fluid
communication between the suction chamber of the rear head and the
cylinders of the cylinder block. A seal is disposed adjacent the
rotary valve and engages at least a portion of the wall defining
the suction chamber.
[0012] According to a further embodiment of the invention, a
variable displacement compressor is disclosed including a cylinder
block having a plurality of cylinders annularly formed therein and
a centrally formed aperture. A plurality of pistons are received
within the cylinders. A rear head is disposed adjacent one end of
the cylinder block. The rear head has a wall defining a suction
chamber. A crank case forms a crank chamber adjacent an other end
of the cylinder block. A drive shaft is rotatably received in the
aperture of the cylinder block and extends through the crank
chamber. A swash plate assembly is rotatably coupled to the drive
shaft. The swash plate assembly is operably coupled to the pistons
to cause a reciprocating motion thereof. A rotary valve is coupled
to the drive shaft and configured to selectively permit fluid
communication between the suction chamber of the rear head and the
cylinders of the cylinder block. A seal is disposed adjacent the
rotary valve and has a bevel formed on an outer surface thereof,
the bevel engaging the wall of the rear head forming the suction
chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above, as well as other advantages of the present
invention, will become readily apparent to those skilled in the art
from the following detailed description of a preferred embodiment
when considered in the light of the accompanying drawings in
which:
[0014] FIG. 1 is a cross-sectional elevational view of a variable
displacement compressor according to an embodiment of the
invention;
[0015] FIG. 2 is a front elevational view of a rotary valve of the
variable displacement compressor of FIG. 1;
[0016] FIG. 3 is a left side elevational view of the rotary valve
of FIG. 2;
[0017] FIG. 4 is a right side perspective view of the rotary valve
of FIGS. 2 and 3;
[0018] FIG. 5 is an enlarged fragmentary cross-sectional
elevational view of the variable displacement compressor
highlighted by circle 5 in FIG. 1, showing a valve plate assembly
according to an embodiment of the invention;
[0019] FIG. 6 is a left side perspective view of a valve plate and
a wear plate of the valve plate assembly of FIG. 5;
[0020] FIG. 7 is side perspective view of a seal cooperating with a
rotary valve of the variable displacement compressor of FIG. 1;
and
[0021] FIG. 8A is an enlarged fragmentary cross-sectional
elevational view of the variable displacement compressor
highlighted by circle 8A in FIG. 1, showing a seal according to an
embodiment of the invention;
[0022] FIG. 8B is an enlarged fragmentary cross-sectional
elevational view of the variable displacement compressor
highlighted by circle 8B in FIG. 1, showing a seal and an urging
member according to another embodiment of the invention; and
[0023] FIGS. 9A-9D are a left side schematic diagram of the rotary
valve at varying rotational positions with respect of a valve plate
assembly and a cylinder block.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION
[0024] The following detailed description and appended drawings
describe and illustrate various exemplary embodiments of the
invention. The description and drawings serve to enable one skilled
in the art to make and use the invention, and are not intended to
limit the scope of the invention in any manner.
[0025] FIG. 1 illustrates a variable displacement compressor 10
according to an embodiment of the invention. The compressor 10
includes a cylinder block 12 having a plurality of cylinders 14
annularly formed therein and reciprocatingly receiving a plurality
of pistons 16. Beating shoes 17 operatively engage the pistons 16
with a swash plate assembly 18 disposed at an inclination angle.
The swash plate assembly 18 is rotatingly coupled to a rotor
assembly 20 to convert rotary movement of the rotor assembly 20 to
reciprocating movement of the pistons 16 within the cylinders 14.
The rotor assembly 20 is rotatingly coupled to a drive shaft 24. A
hinge mechanism 26 couples the swash plate assembly 18 to the rotor
assembly 20 to cause the swash plate assembly 18 to rotate with the
drive shaft 24 and variably change inclination angles with respect
to the rotor assembly 20.
[0026] A rear head 28 is disposed adjacent one end of the cylinder
block 12 and sealingly closes the end of the cylinder block 12. A
valve plate assembly 30 is disposed between the cylinder block 12
and the rear head 28. The rear head 28 includes a suction chamber
32 for receiving a refrigerant gas and a discharge chamber 34 for
receiving a compression gas. The suction chamber 32 communicates
with the cylinders 14 through suction slots 36 formed in the valve
plate assembly 30, wherein each of the suction slots 36 is are
aligned with one of the cylinders 14. The cylinders 14 communicate
with the discharge chamber 34 through a discharge port 38 disposed
in the valve plate assembly 30. A crank case 40 is sealingly
disposed adjacent an opposing end of the cylinder block 12. The
crank case 40 and the cylinder block 12 cooperate to form an
airtight crank chamber 42.
[0027] The drive shaft 24 is centrally disposed in and extends
through the crank case 40 and the cylinder block 12. The drive
shaft 24 is rotateably and linearly supported by bearings mounted
in the crank 40 and the cylinder block 12. The rotor assembly 20
and the swash plate assembly 18 are disposed within the crank
chamber 42. The swash plate assembly 18 is slideably and swingably
supported by the drive shaft 24 extending through an aperture 56
formed in the swash plate assembly 18. A spring 58 surrounds an
outer surface of the drive shaft 24 and is interposed between the
rotor assembly 20 and the swash plate assembly 18.
[0028] A rotary valve 62 and seal 200 are centrally received in the
suction chamber 32 and extends through an aperture 64 formed in a
center portion of the cylinder block 12. A first end 23 of the
drive shaft 24 partially extends into the suction chamber 32. The
rotary valve 62 is coupled to rotate with and radially aligned with
the first end 23 of the drive shaft 24 and is adapted to
selectively seal each of suction slots 36 aligned with each of the
cylinders 14 during a rotation of the rotary valve 62. The rotary
valve 62 is axially secured to the drive shaft 24 by a retaining
feature 66. In certain embodiments, as illustrated in the
embodiment shown in FIG. 1, the retaining feature 66 shown is a
retaining nut and bearings. However, it is understood that the
retaining feature 66 can be any feature configured to axially
secure the rotary valve 62 to the drive shaft 24 such as a
retaining pin, latch, clamp or any other retaining feature, as
desired. The rotary valve 62 is radially aligned with the drive
shaft 24 with a locating feature (not shown) disposed on or
integrally formed with the drive shaft 24. In a non-limiting
example, the locating feature can be a key or spline, for example.
However, it is understood, the locating feature can be any locating
feature such as locating pins or cams or any other locating feature
as desired. The seal 200 is disposed adjacent the rotary valve 62
and will be described in greater detail below.
[0029] FIGS. 2-4 show the rotary valve 62. The rotary valve 62 is
substantially mushroom shaped and includes a disc portion 70
integrally formed with a stem portion 72. The disc portion 70 has a
first surface 74, a second surface 76, and an outer circumferential
wall 84. The disc portion radially extends between walls 60 of the
rear head 28 forming the suction chamber 34. An aperture 80 is
centrally formed in the rotary valve 62 and is configured to
receive the drive shaft 24. A locating slot 82 continuous with the
aperture 80 is formed in the rotary valve 62 and configured to
engage with the locating feature of the drive shaft 24. In certain
embodiments, the rotary valve 62 includes a balancing feature 88,
such as a protrusion 89 and a recess 90 formed on the first surface
74 of the disc portion 70. The protrusion 89 is configured as a
counterweight. Each of the protrusion 89 and the recess 90 is
configured to balance the rotary valve 62 against a suction force
as the rotary valve 62 rotates and militate against deflections
thereof. The balancing feature can be any balancing feature as
desired such as any surface feature, weight, or any other force
generating mechanical device to balance the rotary valve 62, for
example. The rotary valve 62 can be formed from durable material
such as aluminum, aluminum alloy, or steel, for example. Although,
other materials or coatings or combinations of materials and
coatings can be used as desired such as steel, polyether ether
ketone (PEEK), polytetrafluoroethylene (PTFE), electroless nickel
alloys, or any other metal or material as desired.
[0030] The disc portion 70 further includes a suction opening 86
configured to align with the suction slots 36 formed in the valve
plate assembly 30 and the corresponding cylinders 14. The suction
opening 86 extends arcuately in respect of a center of the disc
portion 70 and is disposed at a radial distance from the center of
the rotary valve 62 to axially align a flow of refrigerant from the
suction chamber 32 to each cylinder 14. The suction opening 86
illustrated is a continuous arcuate shaped opening. However, the
suction opening 86 can be a series of separate suction openings.
The suction opening 86 can also be any shape such as circular,
rectangular, ovular, or any other shape as desired to align with
the suction slots 36 and corresponding ones of the cylinders 14.
The suction opening 86 extends arcuately at an angle a so that the
suction opening 86 axially aligns with at least two suction slots
36 and corresponding ones of the cylinders 14 at any given position
of rotation. For example, the suction opening 86 can be adapted to
extend at the angle a to axially align with four suction slots 36
and corresponding ones of the cylinders 14. In certain embodiments,
the angle a can be between about 90 degrees and 170 degrees such as
148 degrees, for example. Although the angle a can be any angle
less than 90 degrees or greater than 150 degrees as desired.
[0031] The stem portion 72 is substantially cylindrical to
facilitate coupling to the drive shaft 24 and extends through an
aperture formed in the cylinder block 12. A collar 78 is formed
adjacent the second surface 76 of the disc portion 70 in the stem
portion 72. The collar 78 is an inwardly projecting recess that
cooperates with the cylinder block 12 to facilitate smooth rotation
of the rotary valve 62. In certain embodiments, the stem portion 72
can be coated or sprayed with a low friction or seizure resistant
material to facilitate bearing characteristics so that the stem
portion 72 can be configured as a shaft bearing interfacing with
the cylinder block 12. The low friction or seizure resistant
material can be PTFE, Ni-PTFE, or any other low friction material
or coating as desired.
[0032] The rotary valve 62 further includes a distribution feature
92 configured to generate a film of lubricant thereon. The
lubricant is a volume of oil contained in the crank case 40 that
flows from the crank case 40 to the suction chamber 32. The
distribution feature shown includes a plurality of grooves 94
formed on the outer wall 84 of the disc portion 70 of the rotary
valve 62 and a channel 98 formed on the second surface 76 of the
disc portion 70 of the rotary valve 62. The grooves 94 are in fluid
communication with the channel 98 via a radially formed passage 100
extending from the outer wall 84 to an opening 102 formed on the
second surface 76 of the rotary valve 62 and continuous with the
channel 98. The distribution feature 92 is configured to convey the
lubricant to the outer wall 94 of the rotary valve 62, where a film
of lubricant is formed to facilitate a seal at an interface of the
rotary valve 62 and the rear head 28 and/or valve plate assembly
30.
[0033] FIGS. 5-6 illustrate an embodiment of the valve plate
assembly 30. The valve plate assembly 30 includes an outer portion
104 which interfaces with the outer wall 84 of the disc portion 70
of the rotary valve 62 and an inner portion 106 that interfaces
with the second surface 76 of the disc portion 70 of the rotary
valve 62. The outer portion 104 overlaps the inner portion 106. The
outer portion 104 has a thickness greater than a thickness of the
inner portion 106. In certain embodiments, the valve plate assembly
30 includes a valve plate 30a disposed circumferentially about the
disc portion 70 of the rotary valve 62 and a wear plate 30b at
least partially interfacing with the valve plate 30a. The wear
plate 30b also interfaces with the second surface 76 of the disc
portion 70 of the rotary valve 62. As illustrated in FIG. 5, the
valve plate assembly 30 can include one or more reed valve flapping
elements 30c such as a discharge reed and a reed valve retaining
member and/or discharge gaskets. The valve plate assembly 30 can
also include a suction gasket, if desired.
[0034] Referring to FIG. 6, a valve plate 30a and wear plate 30b
are illustrated. The valve plate 30a overlays the wear plate 30b.
The valve plate 30a is planar and includes a centrally formed
aperture 108 having a diameter substantially equal to a diameter of
the disc portion 70 to receive the disc portion 70 of the rotary
valve 62. Discharge ports 110 are radially formed in the valve
plate 30a and spaced apart to align with each of the cylinders 14.
The valve plate 30a can be formed from a material having a
coefficient of thermal expansion substantially the same as a
coefficient of thermal expansion of the material forming the rotary
valve 62 and/or substantially the same as a coefficient of thermal
expansion of the material forming the cylinder block 12. The wear
plate 30b includes a centrally formed aperture 112 having a
diameter substantially equal to the diameter of the stem portion 72
of the rotary valve 62 to receive the stem portion 72 of the rotary
valve 62. Discharge ports 114 are radially formed in the wear plate
30b and are spaced apart to align with the discharge ports 110 of
the valve plate 30a and the cylinders 14. The suction slots 36 are
formed in the wear plate 30b. Each of the suction slots 36 have a
shape corresponding to a segment of one of the cylinders 14 and
align therewith. The wear plate 30b is formed from a wear resistant
and flexible material to facilitate a deflection thereof. The wear
plate 30b can be coated or sprayed with a low friction or seizure
resistant material such as PTFE or MoS.sub.2 or any other low
friction coating as desired.
[0035] In FIGS. 7-8A, the seal 200 is illustrated. The seal 200 has
an annular body 205 configured to engage the first surface 74 of
the rotary valve 62 along an outer periphery thereof and the wall
60 of the rear head 28 defining the suction chamber 32. The annular
body 205 has a diameter substantially equal to the diameter of the
disc portion 70 of the rotary valve 62. As shown, the annular body
205 has a substantially rectangular cross-sectional shape to
conform to the shape of the rotary valve 62 and the rear head 28 in
order to create a seal. However, the seal 200 can have other
cross-sectional shapes as desired to form a seal as desired, such
as circular, triangular, or obround, for example.
[0036] In certain embodiments, an outer surface 210 of the annular
body 205 can include a bevel 220 formed thereon. The bevel 220 can
have a bevel angle .theta. to conform to a shape of the wall 60 of
the rear head 28 forming the suction chamber 32 and configured to
provide a preload F to the seal 200 during assembly. In a
non-limiting example, the bevel angle .theta. can be equal to 70
degrees to provide a 200 N preload to the seal 200 during assembly.
However, the bevel angle .theta. can be any angle as desired such
as 80 degrees, 60 degrees, 45 degrees, etc. The bevel 220 is
configured to interface with the wall 60 of the rear head 28
forming the suction chamber 32 to urge the seal towards the rotary
valve 62 during operation.
[0037] The seal 200 further includes position tabs 230 extending
laterally outwardly from the annular body 205 and configured to
cooperate with the rear head 28 to militate against rotation of the
seal 200 or relative movement between the seal 200 and the rear
head 28. The position tabs 230 have a shape corresponding to a
shape of recesses (not shown) formed in the wall 60 of the rear
head 28 forming the suction chamber 32. In the embodiment
illustrated, four position tabs 230 extend from the annular body
205. However, any number of position tabs 230 can extend from the
annular body 205, as desired. The seal 200 can be formed from a
PEEK-HPV material or other PEEK materials, for example. Although,
other materials can be employed as desired. It is understood, the
rotary valve 62 can include a machined surface, as desired, to
facilitate the seal 200 interfacing with the rotary valve 62.
[0038] In FIG. 8B, an urging member 250 can be disposed adjacent
the seal 200 to further facilitate sealing. The urging member 250
engages the wall 60 of the rear head 28 forming the suction chamber
32 and the seal 200 and the first surface 74 of the rotary valve
62. In the exemplary embodiment of FIG. 8B, the urging member 250
is an elastomer element such as an o-ring configured to urge the
seal 2200 towards the rotary valve 62. However, the urging member
250 can be any other mechanism, as desired, such as a spring (e.g.
a wave spring), a pressurized gas, or any other mechanism
configured to urge the seal 200 towards the rotary valve 62, for
example.
[0039] To assemble, the valve plate assembly 30 is positioned
adjacent the cylinder block 12 so that each of the suction slots 36
align with a segment of one cylinder 14. The rotary valve 62 is
coupled to the first end 23 of the drive shaft 24 so that the
rotary valve 62 is at least partially received in the suction
chamber 32 and partially received in the cylinder block 12. The
stem portion 72 of the rotary valve is received through the
centrally formed aperture of the wear plate 30b so that the second
surface 76 of the disc portion 70 of the rotary valve 62
substantially interfaces with the wear plate 30b. The disc portion
70 is received through the centrally formed aperture of the valve
plate 30a so that the outer wall 84 of the disc portion 70
substantially interfaces with the valve plate 30 and a wall of the
rear head 28 forming the suction chamber 32. In certain
embodiments, the reed valve elements 30c can also be disposed
adjacent the valve plate assembly 30. The rotary valve 62, the
valve plate 30a, and the wear plate 30b are positioned to be
concentrically aligned. The seal 200 is disposed adjacent the
rotary valve 62 so that the seal 200 engages the first surface 74
of the disc portion 70 of the rotary valve 62. The rear head 28 is
positioned about the seal 200 so the seal 200 engages the wall 60
of the rear head 28 forming the suction chamber 32. The seal 200 is
positioned so the bevel 220 engages the wall 60 of the rear head 28
to cause a preload on the seal 200 during assembly. The seal 200 is
positioned so the tabs 230 cooperate with the wall 60 of the rear
head 28 forming the suction chamber 32 to militate against the seal
200 from rotating therein or relative movement between the seal 200
and the rear head 28. The urging member 250 can be disposed
intermediate the wall 60 of the rear head 28 forming the suction
chamber 32 to further cause an additional preload to urge the seal
200 towards the rotary valve 62.
[0040] In operation, the drive shaft 24 is caused to rotate by an
auxiliary drive means (not shown) such as an engine of a vehicle,
for example. Rotation of the drive shaft 24 causes a corresponding
rotation of the rotor assembly 20. The swash plate assembly 18 is
connected to the rotor assembly 20 by the hinge mechanism 26 which
allows the swash plate assembly 18 to rotate with the rotor
assembly 20. During rotation, the inclination angle of the swash
plate assembly 18, which can be varied as known in the art, is
converted into the reciprocation of the pistons 16 within the
cylinders 14 by the bearing shoes 17. A suction of a refrigerant
gas and a compression of the refrigerant gas are repeated due to
continuance of the reciprocation of the pistons 16.
[0041] As each of the pistons 16 transition from a top dead center
(TDC) position to a bottom dead center position (BDC) within the
cylinders 14, a suction pressure is generated. Likewise, as each of
the pistons 16 transition from the BDC to the TDC a discharge
pressure is generated. The refrigerant gas is received in the
suction chamber 32 from an external refrigerant circuit (not
shown). The refrigerant gas is conveyed from the suction chamber 32
through the suction slots 36 formed in the valve plate assembly 30
to each of the cylinders 14 upon a generation of the suction
pressure by the pistons 16, and the refrigerant gas is subjected to
compression. The compressed refrigerant gas is discharged to the
discharge chamber 34 through the discharge port 38 formed in the
valve plate assembly 30 upon a generation of the discharge pressure
of the pistons 16. As the rotary valve 62 rotates, the compressed
refrigerant gas is prevented from entering the suction chamber 34
during discharge of compressed gas thereof by closing the suction
slots 36 formed in the valve plate assembly 30 and the refrigerant
gas successively enters the cylinders 14 during a suction thereof
which will be described in greater detail below.
[0042] Referring to FIGS. 9A-9D, a schematic diagram of the suction
opening 86 successively cooperating with the cylinders as the
rotary valve 62 rotates is shown according to an embodiment of the
invention. A direction of rotation R of the rotary valve 62 is
indicated by an arrow. In the embodiment illustrated, seven
cylinders 14a, 14b, 14c, 14d, 14e, 14f, 14g are illustrated.
However, the rotary valve 62 can be adapted to cooperate with any
number of cylinders as desired such as fewer than seven cylinders
or more than seven cylinders.
[0043] In FIG. 9A, the rotary valve 62 is positioned at a reference
angle .theta..sub.o, wherein the reference angle .theta..sub.o
represents the rotational position of the rotary valve 62 when the
suction opening 86 is approaching the cylinder 14a. The piston 16
within the cylinder 14a is at the TDC position. In the embodiment
illustrated an angle .delta. of the suction opening 86 is about 148
degrees. However, it is understood the angle .delta. of the suction
opening 86 can be any angle as desired. In this position of the
rotary valve 62, the suction opening 86 is also at least partially
aligned with three other cylinders 14b, 14c, 14d, wherein the
pistons 16 in each of the cylinders 14b, 14c, 14d are in the
process of a suction stroke. The suction slots 36 to the cylinders
14a, 14e, 14f, 14g are closed by the second surface 76 of the disc
portion 70 of the rotary valve 62. The pistons 16 of the cylinders
14e, 14f, 14g are in the process of a discharge stroke.
[0044] In FIG. 913, the rotary valve 62 is rotated from the
reference angle .theta..sub.o to an angle .dwnarw..sub.1 which can
be 25.degree., for example. As the rotary valve 62 rotates from the
reference angle .theta..sub.o to the angle .theta..sub.1, the
piston 14 in the cylinder 14a begins a suction stroke. The suction
opening 86 directly aligns with the cylinder 14a and corresponding
suction slot 36 so the refrigerant gas flows directly from the
suction chamber 32, through the suction slot 36 to the cylinder
14a. At this position of the rotary valve 62, the suction opening
86 is also aligned with the cylinders 14b, 14c wherein the piston
16 in the cylinders 14b, 14c are in the process of a suction
stroke. The suction slots 36 to the cylinders 14d, 14e, 14f, 14g
are closed by the second surface 76 of disc portion 70 of the
rotary valve 62. The pistons 16 of the cylinders 14d, 14e, 14f, 14g
are in the process of a discharge stroke.
[0045] In FIG. 9C, the rotary valve 62 is rotated from the
reference angle .theta..sub.1 to an angle .theta..sub.2 which can
be 90.degree., for example. As the rotary valve 62 continues to
rotate from the reference angle .theta..sub.oto the angle
.theta..sub.2, the piston 14 in the cylinder 14a is continuing to
perform the suction stroke. The suction opening 86 remains aligned
with the cylinder 14a and corresponding suction slot 36 so the
refrigerant gas can continue to flow from the suction chamber 32,
through the suction slot 36 to the cylinder 14a. At this position
of the rotary valve 62, the suction opening 86 is also aligned with
the cylinder 14g, wherein the piston 16 in the cylinder 14g has
begun to perform the suction stroke, and cylinder 14b, wherein the
piston 16 in the cylinder 14b is still in the process of performing
the suction stroke. The suction slots 36 to the cylinders 14c, 14d,
14e, 14f are closed by the second surface 76 of the disc portion 70
of the rotary valve 62. The pistons 16 of the cylinders 14c, 14d,
14e, 14f are in the process of a discharge stroke.
[0046] In FIG. 9D, the rotary valve 62 is rotated from the
reference angle .theta..sub.2 to an angle .theta..sub.3 which can
be 180.degree., for example. At this rotational position of the
rotary valve 62, the piston 14 in the cylinder 14a is at the BDC
position. The second surface 76 of the disc portion 70 closes the
suction slot 36 corresponding with the cylinder 14a. At this
position of the rotary valve 62, the suction opening 86 is aligned
with the cylinder 14e, 14f, 14g, wherein the piston 16 in the
cylinders 14e, 14f, 14g are performing the suction stroke. The
suction slots 36 to the cylinders 14a, 14b, 14c, 14d are closed by
the second surface 76 of the disc portion 70 of the rotary valve
62. The pistons 16 of the cylinders 14c, 14d, 14e, 14f are in the
process of the discharge stroke.
[0047] During operation, the rotary valve 62 is configured so the
refrigerant gas flowing from the suction chamber 32 to the
respective cylinders 14 flows in a direction substantially parallel
to a direction of the pistons traveling from TDC to BDC or
substantially parallel to a longitudinal direction of the cylinders
14. According to this embodiment, the rotary valve 62 facilitates
the direct flow of refrigerant gas from the suction chamber to the
respective cylinder during the suction stroke and closes the flow
path of the refrigerant gas during the compression and discharge
stroke. This militates against undesired dead volume being added to
each cylinder, undesired flow losses, and facilitates sealing. The
shape and material of the rotary valve 62 and balancing feature 88
militate against deflection of the rotary valve 62, which militates
against leakage of the refrigerant gas into undesired locations of
the compressor 10. Further militating against leakage is the
lubricant being disbursed to the outer wall 84 of the disc portion
70 of the rotaty valve via the distribution feature 92. The
distribution feature 92 also facilitates lubrication of the rotary
valve 62 with respect to the valve plate assembly 30, drive shaft
24, and rear head 28.
[0048] The direct coupling of the rotary valve 62 to the drive
shaft 24 facilitates accurate opening and closing of the suction
slot 36 regardless of the speed of the rotation of the drive shaft
24. The structure of the valve plate assembly 30, particularly the
wear plate 30b being formed from a wear proof material, is caused
to deflect into the rotatory suction valve 62 during compression of
the refrigerant gas. This deflection improves sealing. The outer
portion 104 of the wear plate 30b which has a thickness greater
than the inner portion 106 thereof militates against deflection and
substantially ensures sealing. The inner portion 106 is thinner to
minimize dead volume of the cylinders 14.
[0049] As the rotary valve 62 rotates, the seal 200, cooperating
with the rear head 28, is urged towards the rotary valve 62 to seal
a refrigerant gas leak path that can be formed. The refrigerant gas
leak path is formed intermediate the outer wall 84 of the rotary
valve 62 and the wall 60 of the rear head 28 forming the suction
chamber 32 and/or the valve plate assembly 30. The seal 200
militates against compressed refrigerant gas leaking into the
suction chamber 32. The seal 200 remains positioned adjacent and in
mating contact with the rotary valve 62 and does not rotate as the
rotary valve 62 rotates due to the tabs 230. Minimizing the leakage
of the refrigerant gas maximizes compressor performance.
[0050] From the foregoing description, one ordinarily skilled in
the art can easily ascertain the essential characteristics of this
invention and, without departing from the spirit and scope thereof,
can make various changes and modifications to the invention to
adapt it to various usages and conditions.
* * * * *