U.S. patent application number 14/246297 was filed with the patent office on 2015-10-08 for valve structure for a compressor.
The applicant listed for this patent is HALLA VISTEON CLIMATE CONTROL CORP.. Invention is credited to Michael Gregory Theodore, JR..
Application Number | 20150285231 14/246297 |
Document ID | / |
Family ID | 54209365 |
Filed Date | 2015-10-08 |
United States Patent
Application |
20150285231 |
Kind Code |
A1 |
Theodore, JR.; Michael
Gregory |
October 8, 2015 |
VALVE STRUCTURE FOR A COMPRESSOR
Abstract
A variable displacement compressor includes a rotary valve
coupled to a drive shaft. The rotary valve is centrally received in
a suction chamber of the variable displacement compressor and
extends through an aperture formed in a cylinder block thereof. The
rotary valve has a suction opening cooperating with the cylinders
to successively provide a direct fluid communication between the
suction chamber and each of the cylinders.
Inventors: |
Theodore, JR.; Michael Gregory;
(Plymouth, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HALLA VISTEON CLIMATE CONTROL CORP. |
Daejeon |
|
KR |
|
|
Family ID: |
54209365 |
Appl. No.: |
14/246297 |
Filed: |
April 7, 2014 |
Current U.S.
Class: |
417/516 ;
251/304 |
Current CPC
Class: |
F04B 27/1054 20130101;
F04B 27/0895 20130101; F04B 27/1009 20130101; F04B 27/1063
20130101 |
International
Class: |
F04B 7/00 20060101
F04B007/00 |
Claims
1. A rotary valve for controlling a supply of refrigerant gas to
cylinders in a variable displacement compressor, the rotary valve
comprising: a disc portion; a substantially cylindrical stem
portion extending axially from the disc portion, the disc portion
and the stem portion configured to be coupled to a drive shaft of
the compressor; and a suction opening formed in the disc portion
and configured to permit direct fluid communication between a
suction chamber and at least one cylinder of the compressor.
2. The rotary valve of claim 1, wherein the suction opening has a
shape adapted to axially align the suction opening with a shape of
a portion of the at least one cylinder.
3. The rotary valve of claim 1, wherein the suction opening extends
arcuately in the disc portion at an angle between about 90 degrees
and 180 degrees.
4. The rotary valve of claim 1, wherein the disc portion includes a
balancing feature formed thereon.
5. The rotary valve of claim 1, further comprising an aperture
centrally disposed in the stem portion and extending through the
disc portion and a slot continuous with the aperture, the aperture
and the slot are configured for receiving the drive shaft.
6. The rotary valve of claim 1, further comprising a distribution
feature including a channel formed on a first surface thereof for
receiving a lubricant and a plurality of grooves formed on an outer
wall thereof, the plurality of grooves in fluid communication with
the channel.
7. The rotary valve of claim 1, wherein at least a portion of at
least one of the stem portion and the disc portion is formed from
one of a ferrous material and aluminum and coated with at least one
of a low friction and seizure resistant material.
8. 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 including a disc portion,
a substantially cylindrical stem portion extending axially from the
disc portion, the disc portion and the stem portion configured to
be coupled to a drive shaft of the compressor, and a suction
opening formed in the disc portion; a valve plate assembly
including a central aperture formed therein, the aperture receiving
the rotary valve; and a plurality of suction apertures formed in
the valve plate assembly, wherein the suction opening aligns with
at least one of the suction apertures to permit direct fluid
communication between a suction chamber and at least one cylinder
of the compressor.
9. The rotary valve assembly of claim 8, wherein the suction
opening extends arcuately in the disc portion between about 90
degrees and 180 degrees.
10. The rotary valve assembly of claim 8, wherein the rotary valve
includes an aperture centrally disposed therein and a slot
continuous with the aperture for receiving the drive shaft.
11. The rotary valve assembly of claim 8, wherein the valve plate
assembly includes an outer portion and an inner portion, the outer
portion having a thickness greater than a thickness of the inner
portion.
12. The rotary valve assembly of claim 8, wherein the valve plate
assembly includes a valve plate and a wear plate, the valve plate
having a centrally disposed aperture for receiving the disc portion
of the rotary valve and the wear plate having a centrally disposed
aperture for receiving the stem portion of the rotary valve.
13. The rotary valve assembly of claim 12, wherein the valve plate
is formed from a material having a coefficient of thermal expansion
substantially the same as a coefficient of thermal expansion of at
least one of the rotary valve, a cylinder block of the compressor,
and a rear head of the compressor defining the suction chamber.
14. 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 and defining a suction chamber and discharge
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, the rotary valve centrally received in the suction
chamber and extending through the aperture formed in the cylinder
block, wherein the rotary valve has a suction opening cooperating
with the cylinders to successively provide a direct fluid
communication between the suction chamber and each of the
cylinders.
15. The variable displacement compressor of claim 14, wherein a
direction of flow of a refrigerant gas from the suction chamber to
the cylinders is parallel to a longitudinal axis of the
cylinders.
16. The variable displacement compressor of claim 14, wherein the
rotary valve includes a disc portion, a substantially cylindrical
stem portion integrally formed with and extending axially from the
disc portion, the disc portion and the stem portion configured to
be coupled to a drive shaft of the compressor, the suction opening
formed in the disc portion.
17. The variable displacement compressor of claim 14, wherein the
suction opening successively aligns with each of the cylinders
during a suction stroke of the each of the pistons therein.
18. The variable displacement compressor of claim 14, further
comprising a valve plate assembly disposed intermediate the
cylinder block and the rotary valve, the valve plate assembly
having a plurality of suction apertures formed therein, each of the
suction apertures aligning with one of the cylinders.
19. The variable displacement compressor of claim 18, wherein the
valve plate assembly includes a valve plate and a wear plate, the
valve plate having a centrally disposed aperture for receiving the
disc portion of the rotary valve and the wear plate having a
centrally disposed aperture for receiving the stem portion of the
rotary valve,
20. The variable displacement compressor of claim 14, wherein the
valve plate assembly includes an outer portion and an inner
portion, the outer portion having a thickness greater than a
thickness of the inner portion, wherein the valve plate is formed
from a material having a coefficient of thermal expansion
substantially the same as a coefficient of thermal expansion of at
least one of the rotary valve, the cylinder block, and the rear
head defining 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 rotary valve structure of a variable
displacement compressor 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
for controlling a supply of refrigerant gas to cylinders in a
variable displacement compressor is disclosed. The rotary valve
includes a disc portion and a substantially cylindrical stem
portion extending axially from the disc portion. The disc portion
and the stem portion are configured to be coupled to a drive shaft
of the compressor. A suction opening formed in the disc portion and
configured to permit direct fluid communication between a suction
chamber and at least one cylinder of the compressor.
[0011] According to another 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 including a disc
portion and a substantially cylindrical stem portion extending
axially from the disc portion. The disc portion and the stem
portion are configured to be coupled to a drive shaft of the
compressor. A suction opening is formed in the disc portion. A
valve plate assembly includes a central aperture formed therein.
The aperture receives the rotary valve. A plurality of suction
apertures are formed in the valve plate assembly, wherein the
suction opening aligns with at least one of the suction apertures
to permit direct fluid communication between a suction chamber and
at least one cylinder of the compressor.
[0012] According to a further embodiment of the invention, a
variable displacement compressor is disclosed. A cylinder block has
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 and defining a suction chamber and discharge chamber. A crank
case forming a crank chamber is 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 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. The rotary valve is centrally received in the suction
chamber and extends through the aperture formed in the cylinder
block, wherein the rotary valve has a suction opening cooperating
with the cylinders to successively provide a direct fluid
communication between the suction chamber and each of the
cylinders.
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; and
[0020] FIGS. 7A-7D 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
[0021] 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.
[0022] 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. Bearing 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.
[0023] 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 apertures 36 formed in the
valve plate assembly 30, wherein each of the suction apertures 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.
[0024] 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 case 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.
[0025] A rotary valve 62 is 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 apertures 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.
[0026] 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.
[0027] The disc portion 70 further includes a suction opening 86
configured to align with the suction apertures 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 apertures 36 and corresponding
ones of the cylinders 14. The suction opening 86 extends arcuately
at an angle .alpha. so that the suction opening 86 axially aligns
with at least two suction apertures 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
.alpha. to axially align with four suction apertures 36 and
corresponding ones of the cylinders 14. In certain embodiments, the
angle .alpha. can be between about 90 degrees and 180 degrees such
as 148 degrees, for example. Although the angle .alpha. can be any
angle less than 90 degrees or greater than 180 degrees as
desired.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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 and/or the
rear head 28. 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 apertures 36 are formed in the wear plate 30b. Each of
the suction apertures 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.
[0032] To assemble, the valve plate assembly 30 is positioned
adjacent the cylinder block 12 so that each of the suction
apertures 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.
[0033] 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.
[0034] 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 apertures 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
apertures 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.
[0035] Referring to FIGS. 7A-7D, 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.
[0036] In FIG. 7A, 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 apertures 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, 141, 14g are in the process of a discharge
stroke.
[0037] In FIG. 7B, the rotary valve 62 is rotated from the
reference angle .theta..sub.0 to an angle .theta..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 aperture 36 so the refrigerant gas flows directly from the
suction chamber 32, through the suction aperture 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 apertures 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.
[0038] In FIG. 7C, 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.o to 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 aperture 36 so the
refrigerant gas can continue to flow from the suction chamber 32,
through the suction aperture 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 apertures 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, 141 are in the process
of a discharge stroke.
[0039] In FIG. 7D, 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 aperture 36 corresponding with the cylinder 14a. At this
position of the rotary valve 62, the suction opening 86 is aligned
with the cylinder 14e, 141, 14g, wherein the piston 16 in the
cylinders 14e, 14f, 14g are performing the suction stroke. The
suction apertures 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.
[0040] 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 rotary 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.
[0041] The direct coupling of the rotary valve 62 to the drive
shaft 24 facilitates accurate opening and closing of the suction
aperture 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.
[0042] 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.
* * * * *