U.S. patent application number 09/324250 was filed with the patent office on 2001-06-07 for rotary compressor with vane body immersed in lubricating fluid.
Invention is credited to GANNAWAY, EDWIN L..
Application Number | 20010002981 09/324250 |
Document ID | / |
Family ID | 26779026 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010002981 |
Kind Code |
A1 |
GANNAWAY, EDWIN L. |
June 7, 2001 |
ROTARY COMPRESSOR WITH VANE BODY IMMERSED IN LUBRICATING FLUID
Abstract
A hermetic rotary compressor comprising a housing, a cylinder
block and a bearing assembly in the housing and defining a
cylindrical cavity therein. A roller piston, drivingly coupled to a
motor, is disposed in the cylindrical cavity. The cylinder block
includes a reciprocating vane within a vane slot defined therein.
The vane slot extends axially through said cylinder block, radially
from an outside perimeter surface of the cylinder block to the
cylindrical cavity. At least a portion of the vane slot is defined
by a pair of substantially parallel sidewalls with the vane
disposed in the vane slot and urged against the roller piston. The
vane is guided by the substantially parallel sidewalls and a
clearance exists between the vane and the substantially parallel
sidewalls. A pool of liquid lubricant is disposed within a sump
defined by a discharge chamber and a lower portion of the vane and
the clearance are immersed in the liquid lubricant, whereby the
vane is lubricated and a refrigerant gas seal is established
between the clearance and the vane.
Inventors: |
GANNAWAY, EDWIN L.; (ADRIAN,
MI) |
Correspondence
Address: |
JOHN F HOFFMAN
BAKER & DANIELS
111 EAST WAYNE STREET
SUITE 800
FORT WAYNE
IN
46802
|
Family ID: |
26779026 |
Appl. No.: |
09/324250 |
Filed: |
June 2, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60088754 |
Jun 10, 1998 |
|
|
|
Current U.S.
Class: |
418/60 ; 418/63;
418/96 |
Current CPC
Class: |
F01C 21/108 20130101;
F04C 23/008 20130101; F04C 2230/602 20130101; F04C 2240/603
20130101; F04C 23/001 20130101; F04C 29/02 20130101; F04C 18/3442
20130101; F01C 21/0809 20130101; F01C 21/104 20130101 |
Class at
Publication: |
418/60 ; 418/63;
418/96 |
International
Class: |
F04C 018/356; F04C
029/02 |
Claims
What is claimed is:
1. A hermetic rotary compressor assembly, comprising: a housing; a
cylinder block and bearing assembly in said housing, said cylinder
block and bearing assembly defining a cylindrical cavity; a roller
piston disposed in said cavity; a motor drivingly coupled to said
roller piston; said cylinder block having a vane slot extending
axially through said cylinder block and extending radially from an
outside perimeter surface of said cylinder block to said
cylindrical cavity; at least a portion of said slot defined by a
pair of substantially parallel sidewalls, a vane disposed in said
slot and urged against said roller piston, said vane guided by said
substantially parallel sidewalls, there being a clearance between
said vane and said substantially parallel sidewalls; and a
discharge chamber comprising a sump in which a pool of liquid
lubricant is disposed, a lower portion of said vane and said
clearance immersed in said liquid lubricant, whereby said vane is
lubricated and a refrigerant gas seal is established between said
clearance and said vane.
2. The compressor assembly of claim 1, wherein a substantial
portion of said vane slot sidewalls are disposed below an upper
surface of the pool of liquid lubricant.
3. The compressor assembly of claim 1, and including a second
rotary compressor mechanism axially disposed within a second
discharge chamber in said housing, a suction chamber disposed
between said pair of compressor mechanisms, said compressor
mechanisms being substantially identical, said second discharge
chamber comprising a sump in which pool of liquid lubricant is
disposed; said drive motor disposed axially intermediate said pair
of compressor mechanisms and operably coupled to said roller
pistons provided in each said cylinder block, said motor located in
said suction chamber; at least one of said compressor mechanisms
being in fluid communication with said suction chamber; and a pair
of discharge conduits connected with respective said discharge
chambers through which discharge gases exit therefrom.
4. The compressor assembly of claim 3, wherein one of said pair of
discharge conduits fluidly connects said pools of liquid lubricant
in said discharge chambers.
5. The compressor assembly of claim 4, wherein said discharge
chambers are at substantially the same discharge pressure.
6. The compressor assembly of claim 3, wherein the compressor
assembly is horizontally oriented and said pool of liquid lubricant
in each said sump is disposed in a lower portion thereof.
7. The compressor assembly of claim 6, wherein said sidewalls of
each said vane slot are substantially vertical.
8. The compressor of claim 1, wherein said vane slot extends
completely axially through said cylinder block.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is related to and claims the benefit under
35 U.S.C. .sctn.119(e) of United States Provisional Application
Ser. No. 60/088,754, filed Jun. 10, 1998.
BACKGROUND OF INVENTION
[0002] This invention pertains to hermetically sealed, positive
displacement compressors for compressing refrigerant in
refrigeration systems such as air conditioners, refrigerators and
the like. In particular, the invention describes a rotary
compressor mechanism, having a discharge chamber and a sump
disposed therein and being of the type which includes a cylinder
block having a cylindrical cavity, a bearing assembly and a motor
assembly driving a roller piston disposed in the cylindrical
cavity. More particularly, the cylinder block includes a vane slot,
partially defined by a pair of vane slot sidewalls, extending
completely axially through the cylinder block to accommodate a
reciprocating vane therein and the vane being urged against a
roller piston.
[0003] Rotary compressors are well known in the art, as exemplified
by U.S. Pat. No. 4,889,475 which is assigned to assignee of the
present application. Generally, the tolerances between the
reciprocating vane and the slot sidewalls defining the vane slot of
the cylinder block must be tightly controlled in order to optimize
compressor efficiency. Proper vane clearances are necessary to
allow free reciprocation of the vane in its slot and to allow
sealing against discharge pressure gas blow-by therebetween.
Maintaining these clearances in previous compressors often requires
precision vane and/or slot machining, or select fitting of the
individual vanes and cylinder blocks. A disadvantage arising from
precision machining of the slot and/or vane is the associated cost
of precision machining a pair of sidewalls defining the vane slot
and vane. Always existent with precision machining is the immense
cost associated with the act of "scrapping a part" when one of the
final operations is spoiled due to a myriad of possible and easily
made mistakes. A structure for easily providing a seal between the
vane and their slot without resorting to costly and time consuming
machining operations or select fitting is needed.
[0004] Generally, rotary compressor construction includes
laboriously preparing the vane and vane slot for an introduction of
the vane into the vane slot to provide a sealable fit therebetween
when a lubricant is introduced therein. A disadvantage, already
mentioned hereinabove, is that laboriously preparing components,
through precision machining and the like, has an increased cost
associated therewith. Components, such as the vane and vane slot
satisfactorily sealing during operation, without the heretofore
required precise machining of the vane and vane slot would be
highly desirous.
[0005] Generally, rotary compressors heretofore disclosed include
porting or journaling such that through suction of refrigerant gas,
liquid lubricant in one portion of a compressor housing may be
transferred to the cylinder block to fill the clearance between the
vane and vane slot to provide a positive seal. A disadvantage of
this type of lubrication is that liquid lubricant quantities vary
and depend on the suction created by the compressor. Moreover, the
scant amount of liquid lubricant "coating" the clearance between
the vane and vane slot often acts to lubricate the clearance rather
than seal it. A clearance which is sealed, and additionally
lubricated, rather than merely being lubricated is highly
desired.
SUMMARY OF THE INVENTION
[0006] The present invention overcomes the disadvantages of the
prior art described above by providing a hermetically sealed twin
rotary compressor assembly as herein described.
[0007] The present invention provides a hermetic compressor
assembly including a housing, a cylinder block and bearing assembly
within the housing, and additionally, the cylinder block and
bearing assembly define a cylindrical cavity. A roller piston,
disposed within the cylindrical cavity, is drivingly coupled to a
motor. The cylinder block has a vane slot preferably extending
completely axially through the cylinder block and extends radially
from an outside perimeter surface of the cylinder block to the
cylindrical cavity.
[0008] The present invention also provides a pair of sidewalls
defining at least a portion of the vane slot in the cylinder block.
A vane, guided by substantially parallel sidewalls, is disposed in
the vane slot and is urged against the roller piston. A clearance
exists between the vane and the substantially parallel slot walls.
A sump disposed in the discharge chamber having a pool of liquid
lubricant disposed therein. A lower portion of the vane and
clearance is immersed in the liquid lubricant whereby the vane is
lubricated and a refrigerant gas seal is established between the
clearance and the vane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The above-mentioned and other features and objects of this
invention, and the manner of attaining them, will become more
apparent and the invention itself will be better understood by
reference to the following description of the embodiments of the
invention taken in conjunction with the accompanying drawings,
wherein:
[0010] FIG. 1 is a sectional side view of one embodiment of a
compressor assembly according to the present invention, also
showing the cross-over tube fluidly connecting the two discharge
chambers and the compressor assembly discharge tube;
[0011] FIG. 2 is an enlarged fragmentary sectional side view of the
rear portion of the compressor assembly shown in FIG. 1;
[0012] FIG. 3 is a sectional rear view of the compressor assembly
shown in FIG. 2, taken along line 3-3 thereof;
[0013] FIG. 4 is a sectional front view of the compressor assembly
shown in FIG. 2, taken along line 4-4 thereof;
[0014] FIG. 5 is a front view of the front main bearing of the
compressor assembly shown in FIG. 1, including the outline of the
cylinder block location on the axial main bearing surface;
[0015] FIG. 6 is a rear view of the main bearing shown in FIG.
5;
[0016] FIG. 7 is a rear view of the rear main bearing of the
compressor assembly shown in FIG. 1, including the outline of the
cylinder block location on the axial main bearing surface;
[0017] FIG. 8 is a front view of the main bearing shown in FIG.
7;
[0018] FIG. 9 is sectional side view of each of the main bearings
shown in FIGS. 5 and 7, along lines 9-9 thereof;
[0019] FIG. 10 is a fragmentary sectional side view of each of the
main bearings shown in FIGS. 6 and 8, along lines 10-10
thereof;
[0020] FIG. 11 is a front view of the common front and rear
cylinder block of the compressor assembly shown in FIG. 1;
[0021] FIG. 12 is a front view of the front outboard bearing of the
compressor assembly shown in FIG. 1;
[0022] FIG. 13 is a sectional side view of the outboard bearing of
FIG. 12, along line 13-13 thereof;
[0023] FIG. 14 is a rear view of the rear outboard bearing of the
compressor assembly shown in FIG. 1;
[0024] FIG. 15 is a sectional side view of the outboard bearing of
FIG. 14, along line 15-15 thereof;
[0025] FIG. 16A is a partial sectional side view of the shaft of
the compressor assembly shown in FIG. 1;
[0026] FIG. 16B is an enlarged sectional rear view of the shaft
shown in FIG. 16A, along line 16B-16B thereof;
[0027] FIG. 16C is an enlarged sectional front view of the shaft
shown in FIG. 16A, along line 16C-16C thereof;
[0028] FIG. 17A is an enlarged sectional side view of an eccentric
of the compressor assembly shown in FIG. 1;
[0029] FIG. 17B is a sectional end view of the eccentric shown in
FIG. 17A, along line 17B-17B thereof;
[0030] FIG. 18 is a sectional side view of a second embodiment of a
compressor assembly according to the present invention, also
showing the cross-over tube fluidly connecting the two discharge
chambers and the compressor assembly discharge tube;
[0031] FIG. 19 is an enlarged fragmentary sectional side view of
the bottom portion of the compressor assembly shown in FIG. 18;
[0032] FIG. 20 is a sectional plan view of the compressor assembly
shown in FIG. 19, taken along line 20-20 thereof;
[0033] FIG. 21 is a top view of the common upper and lower cylinder
block of the compressor assembly shown in FIG. 18;
[0034] FIG. 22 a bottom view of the lower outboard bearing of the
compressor assembly shown in FIG. 18;
[0035] FIG. 23 is a sectional side view of the outboard bearing of
FIG. 22, along line 23-23 thereof;
[0036] FIG. 24 is a sectional side view of the third embodiment of
a compressor assembly according to the present invention, also
showing the cross-over tube fluidly connecting the two discharge
chambers and the compressor assembly discharge tube;
[0037] FIG. 25 is an enlarged fragmentary sectional side view of
the front portion of the compressor assembly shown in FIG. 24;
[0038] FIG. 26 is a sectional rear view of the compressor assembly
shown in FIG. 25, taken along line 26-26 thereof;
[0039] FIG. 27 is a sectional front view of the compressor assembly
shown in FIG. 25, taken along line 27-27 thereof;
[0040] FIG. 28 is a fragmentary perspective of a common cylinder
block of the compressor assembly shown in FIG. 24, including the
reed valve assembly and extended vane;
[0041] FIG. 29 is a front view of the front main bearing of the
compressor assembly shown in FIG. 24, including the outline of the
cylinder block location on the axial main bearing surface;
[0042] FIG. 30 is a rear view of the main bearing shown in FIG.
29;
[0043] FIG. 31 is a rear view of the rear main bearing of the
compressor assembly shown in FIG. 24, including the outline of the
cylinder block location on the axial main bearing surface;
[0044] FIG. 32 is a front view of the main bearing shown in FIG.
31;
[0045] FIG. 33 is sectional side view of each of the main bearings
shown in FIGS. 30 and 32, along lines 33-33 thereof;
[0046] FIG. 34 is a front view of the common front and rear
cylinder block of the compressor assembly shown in FIG. 24;
[0047] FIG. 35 is a sectional bottom view of the cylinder block of
FIG. 34, along line 35-35 thereof;
[0048] FIG. 36 is a front view of the front outboard bearing of the
compressor assembly shown in FIG. 24;
[0049] FIG. 37 is a sectional side view of the outboard bearing of
FIG. 36, along line 37-37 thereof;
[0050] FIG. 38 is a sectional side view of the outboard bearing of
FIG. 36, along line 38-38 thereof;
[0051] FIG. 39 is an exploded view of the pump assembly and rear
outboard bearing of the present invention shown in FIG. 24;
[0052] FIG. 40 is a partial sectional side view of the shaft of the
compressor assembly shown in FIG. 1;
[0053] FIG. 41 is an enlarged sectional rear view of the shaft
shown in FIG. 40, along line 41-41 thereof;
[0054] FIG. 42 is an enlarged sectional front view of the shaft
shown in FIG. 40, along line 42-42 thereof;
[0055] FIG. 43 is a front perspective view of an eccentric of the
compressor assembly as shown in FIG. 24;
[0056] FIG. 44 is a sectional side view of the eccentric shown in
FIG. 43, along line 44-44 thereof;
[0057] FIG. 45 is a sectional end view of the eccentric shown in
FIG. 44, along line 45-45 thereof;
[0058] FIG. 46 is a sectional side view of a fourth embodiment of a
compressor assembly according to the present invention, also
showing the cross-over tube fluidly connecting the two discharge
chambers and the compressor assembly discharge tube;
[0059] FIG. 47 is a sectional side view of a fifth embodiment of a
compressor assembly according to the present invention, showing the
suction tube fluidly connecting a discharge of one of the
compressor mechanisms to a suction port of the remaining compressor
mechanism and the compressor assembly discharge tube;
[0060] FIG. 48 is a sectional rear view of the compressor assembly
shown in FIG. 47, taken along line 48-48 thereof;
[0061] FIG. 49 is a sectional rear view of the compressor assembly
shown in FIG. 47, taken along line 49-49 thereof;
[0062] FIG. 50 is a simplified model of the common cylinder blocks
of the compressor assemblies shown in FIGS. 1, 18, 24 and 46-47,
showing an inwardly tapered vane slot;
[0063] FIG. 51 is the model cylinder block of FIG. 51, showing a
gauge vane therein, outward forces applied thereto and a state of
circumferentially oriented tensile stress;
[0064] FIG. 52 is the model cylinder block of FIG. 51, showing an
operable vane slot of width "S" and the state of circumferentially
oriented tensile stress preserved therein;
[0065] FIG. 53 is a simplified model of the common cylinder blocks
of the compressor assemblies shown in FIG. 1, 18, 24 and 46-47, and
an alternative to the model cylinder block of FIG. 51, showing an
outwardly tapered vane slot;
[0066] FIG. 54 is the model cylinder block of FIG. 53, showing a
gauge vane therein, inward forces applied thereto and a state of
circumferentially oriented compressive stress; and
[0067] FIG. 55 is the model cylinder block of FIG. 53, showing an
operable vane slot of width "S" and the state of circumferentially
oriented compressive stress preserved therein.
[0068] Corresponding reference characters indicate corresponding
parts throughout the several views. Although the drawings represent
embodiments of the present invention, the drawings are not
necessarily to scale and certain features may be exaggerated in
order to better illustrate and explain the present invention. The
exemplifications set out herein illustrate embodiments of the
invention in alternative forms, and such exemplifications are not
to be construed as limiting the scope of the invention in any
manner.
DETAILED DESCRIPTION OF THE INVENTION
[0069] The embodiments disclosed below are not intended to be
exhaustive or limit the invention to the precise form disclosed in
the following detailed description.
[0070] Referring to FIG. 1, there is shown twin rotary compressor
assembly 10, a first embodiment according to the present invention.
Compressor assembly 10 comprises housing 12 which is itself
comprised of first housing portion 14, second, cylindrical housing
portion 16 and third housing portion 18, first and third housing
portions 14 and 18 being somewhat cup shaped, second housing
portion 16 interposed between housing portions 14 and 18.
Compressor assembly 10 further comprises front and rear main
bearings 20, 22, respectively, which comprise, within housing
portions 14 and 18, respective front and rear compressor mechanisms
24 and 26. As will be discussed further below, front main bearing
20 and rear main bearing 22 are mirror images of each other. Each
of main bearings 20, 22 may be machined from a common casting or,
alternatively, from a common sintered powder metal form. Main
bearings 20 and 22 are respectively provided, at their peripheries,
with annular, oppositely facing control surfaces 28 and 29. Control
surfaces 28 and 29 lie in parallel planes which are perpendicular
to the central axis of each main bearing. The forwardly and
rearwardly facing axial surfaces of cylindrical second housing
portion 16 are each provided with axial counterbore 30 concentric
about the central axis of housing portion 16 and which provides
annular shoulders 31 against which axial surfaces 28, 29 abut.
Shoulders 31 lie in parallel planes which are perpendicular to the
central axis of cylindrical housing portion 16 and provide control
surfaces for proper axial spacing and radial alignment of main
bearings 20, 22, and ensure they fit squarely within housing
portion 16. Proper placement of main bearings 20, 22 allows the
shaft supported thereby to be properly journaled and assures proper
clearances are provided between the moving components which
comprise front and rear compressor mechanisms 24, 26. The mating
axial ends of housing portions 14, 16 and 18 are joined at the
outer radial periphery of respective main bearings 20, 22, to which
they are sealably attached, as by welding. Welding each of housing
portions 14, 16 and 18 to the main bearings separates housing 12
into three distinct internal chambers separated by the main
bearings. Front chamber 32 is generally defined by inside surface
33 of housing portion 14 and forward facing axial surface 34 of
main bearing 20. Similarly, rear chamber 36 is defined by inside
surface 37 of third housing portion 18 and rearward facing axial
surface 38 of rear main bearing 22. As will be discussed further
below, chambers 32 and 36 contain refrigerant gas at discharge
pressure, and are also referred to hereinafter as front and rear
discharge chambers, respectively. Intermediate main bearings 20 and
22 and generally defined by inside cylindrical surface 39 of center
housing portion 16 and surfaces 40 and 42 of front and rear main
bearings 20 and 22, respectively, is chamber 44. Chamber 44, as
will be discussed further below, contains refrigerant gas at
suction pressure, and is hereinafter referred to as suction chamber
44. Within suction chamber 44 is disposed motor assembly 46
comprising stator 48 in surrounding relationship with rotor 50.
Shaft 52 extends through the center of rotor 50, and is attached
thereto to be driven by rotor 50 when motor assembly 46 is
energized through terminals 54, which electrically communicate the
motor with an external source of power. Providing the motor in the
suction chamber provides a cooler operating environment for it,
promoting its efficient operation and prevents its overheating.
Further, placement of the motor assembly in the relatively cool
environment of the suction chamber provides for easier
identification of an internal motor over-temperature condition
vis-a-vis compressors having motors exposed to discharge pressure,
for the temperature protection device (not shown) attached to the
stator windings, which interrupts electrical current to the motor
when it becomes overheated, need not be calibrated to operate in
relatively narrow temperature difference ranges between discharge
gas temperatures to which the motor is ordinarily exposed and the
motor over-temperature point.
[0071] Shaft 52 comprises large diameter central portion 56, which
extends through rotor 50, and forwardly and rearwardly extending
small diameter portions 58 and 60, respectively, adjacent portion
56. At the juncture of shaft portion 56 with shaft portions 58 and
60, shaft 52 is provided with annular groove 57 in which may be
disposed oil seal 59 which may be made of a material such as
Teflon.RTM. or Ryton.RTM. and past which some leakage is
permissible. Annular shoulder 62 is formed on the axial surface of
shaft large diameter portion 56, at its juncture with groove 57.
Thrust washer 64 is disposed about small diameter shaft portion 60,
with its forwardly and rearwardly facing axial surfaces abutting
shaft shoulder 62 and forward facing axial surface 66 of hub
portion 68 of rear main bearing 22. Motor assembly 46 is arranged
such that the windings of stator 48 and rotor 50 are axially offset
by distance .delta.. Upon energization of stator 48, rotor 50 not
only rotates but is also urged rearward as it attempts to axially
align its windings with those of the stator. Rotor 50 thus exerts a
rearward axial force on shaft 52 which is transferred through
shoulder 62 to thrust bearing 64 and opposed by main bearing 22. In
this way, axial surfaces of the eccentrics and adjacent bearings
are not brought into abutment and caused to carry an axial load.
Small diameter shaft portions 58 and 60 are respectively journaled
in main bearing journals 70 and 72, which extend through main
bearing hub portions 74 and 68.
[0072] Front compressor mechanism 24 and rear compressor 26 are
each provided with cylinder block 76. Cylinder block 76 comprises
outer peripheral surface 78 and inner cylindrical cavity 80.
Cylindrical cavity 80 extends through the width of cylinder block
76 between its forward and rearwardly facing parallel axial
surfaces 82 and 84, respectively. In front compressor mechanism 24,
cylinder block rearward surface 84 abuts forwardly facing axial
surface 34 of main bearing 20. Similarly, in rear compressor
mechanism 26, cylinder block forward surface 82 abuts rearwardly
facing main bearing axial surface 38. Thus it can be seen that
cylinder blocks 76 are similarly oriented about shaft 52 in front
and rear compressor mechanisms 24, 26.
[0073] In front compressor mechanism 24, forward cylinder block
surface 82 abuts rearwardly facing axial surface 86 of front
outboard bearing 88. Outboard bearing 88, frontmost cylinder block
76 and front main bearing 20 are attached by a plurality of bolts
90 extending through bolt holes 92, 94 and 96, with bolts 90
threadedly engaging main bearing bolt holes 96. In rear compressor
mechanism 26, rearward cylinder block surface 84 abuts forwardly
facing axial surface 98 of rear outboard bearing 100. As described
above, a plurality of bolts 90 attaches outboard bearing 100,
rearmost cylinder block 76 and rear main bearing 22, extending
through bolt holes 102, 94 and 104 provided therein, threadedly
engaging main bearing bolt holes 104. Small diameter shaft portions
58 and 60 extend through outboard bearings 88 and 100, and are
supported in respective journals 106 and 108 provided therein. As
will be discussed further below, front outboard bearing 88 and rear
outboard bearing 100 are mirror images of one another, and may be
machined together or on common tooling from identical castings or
sintered powder metal forms.
[0074] Shaft 52 is provided with axial bore 110 which extends
completely through its length. At its rearmost end, bore 110 is
provided with impeller-type pump assembly 112 of a type commonly
used in the art. Pump assembly 112 draws liquid lubricant from the
lowermost portion of rear discharge chamber 36, which serves as a
sump, through vertical lubricant draw conduit or tube 114, which
extends downwardly from pump assembly 112. The lowermost portion of
front discharge chamber 32 also contains a quantity of liquid
lubricant, also referred to as oil, as may that of suction chamber
44. Pump assembly 112 provides oil through bore 110 to rear
compressor mechanism 26 and to front compressor mechanism 24 for
lubrication thereof, as will be discussed further below.
[0075] Discharge chambers 32 and 36 are in fluid communication with
one another by means of external cross-over discharge conduit in
the form of a tube 115 which extends axially along the outside of
compressor housing 12 and, referring to FIGS. 3 and 4, extends into
discharge chambers 32 and 36 to the extent that its open ends 116
are disposed above the normal height of a pool of liquid lubricant
having surface level 118. Cross-over tube 115, as initially shown
in FIG. 1 and various Figures thereafter, is an uninterrupted
conduit, however, a sweat fitting or other like sealing fitting may
disrupt the continuity to ease in the assembly process of the
compressor assembly. Discharge pressure gas from front discharge
chamber 32 is provided through cross-over tube 115 to discharge
chamber 36, wherein it joins the discharge pressure gas exhausted
from rear compressor assembly 26 and is discharged from compressor
assembly 10 through discharge conduit or tube 120, which extends
into the upper portion of rear discharge chamber 36. Each pool of
liquid lubricant having level 118 is maintained at approximately
equal heights in both discharge chambers 32 and 36 by excess
lubricant being redistributed between the two discharge chamber
sumps via cross-over tube 115 as level 118 rises above the height
of tube end opening 116 (FIG. 3).
[0076] Referring again to FIG. 1, it can be seen that each
compressor mechanism 24 and 26 is provided with eccentric 122
mounted on respective small diameter shaft portion 58, 60 and
disposed in cavity 80 of each cylinder block 76. Each eccentric 122
is mounted about the axis of shaft 52 180.degree. apart from the
other to ensure proper balance. Further, counterweight 123 may be
provided at opposite axial ends of rotor 50, 180.degree. apart, to
aid in balancing compressor assembly 10. Referring now to FIG. 4,
which illustrates rear compressor mechanism 26 but which may be
analogously applied to understand the structure of front compressor
mechanism 24, it can be seen that eccentric 122 is disposed about
shaft portion 60 and is fixed for rotation therewith by means of
set screw 124 threadedly engaged in hole 126 provided in the
eccentric. Terminal point 128 of set screw 124 is received in
countersink 130 provided in the surface of shaft portion 60. With
reference to FIGS. 2 and 4, it is shown that cylindrical roller
piston 132 is provided about eccentric 122, inside surface 133 of
roller piston 132 in sliding contact with outer peripheral surface
134 of eccentric 122. Further, it can be seen from FIGS. 1 and 2
that the forwardly and rearwardly facing axial surfaces of roller
piston 132 are closely adjacent to the axial surfaces of the main
and outboard bearings, with a maximum axial clearance preferably of
about 0.0007 inch between the piston/bearing interfaces. In the
known manner of operation of rotary compressors, roller piston 132
rotates on the cylindrical surface of cavity 80 in an epicyclic
manner. Outer cylindrical surface 135 of roller piston 132 is in
sliding contact with tip 136 of vane 138. Vane 138 is provided in
each compressor mechanism 24, 26, and is urged into sliding
engagement with roller piston surfaces 135 by means of springs 142
which encircle depending vane posts 144 and abuts vane surfaces 146
adjacent thereto. The opposite ends of springs 142 are retained by
brackets 148 which are attached to surfaces 34 and 38 of main
bearings 20 and 22 by means of rivets 150 provided in holes 152 and
154.
[0077] Referring to FIGS. 2 and 4, it can be seen that vane 138 has
opposite, parallel planar sides 156 and 158, and opposite, parallel
edges 160 and 162. Edges 160, 162 are in sliding engagement with
the respective adjacent axial main and outboard bearing
surfaces.
[0078] Suction gases enter compressor assembly 10 through suction
conduit or tube 164 (FIGS. 1, 3), which extends into suction
chamber 44. The outlet of suction tube 164 is covered by filter 165
in which debris carried by refrigerant returning to the compressor
assembly may be captured. Filter 165 may be a wire cloth or finely
meshed screen which may be spot welded over or press-fitted into
the end of tube 164. Filter 165 may be 100 mesh wire screen,
comprising 100 interwoven wires of 0.007 inch diameter per inch,
which would only allow particles smaller than approximately 0.003
inch to pass through to chamber 44. Because the suction gases
returning the compressor assembly are directed through suction tube
164 into chamber 44, which provides a relatively large expansion
volume, a refrigerant system incorporating the inventive compressor
would not ordinarily require an in-line suction muffler external to
the compressor assembly.
[0079] Suction chamber 44 will contain a quantity of lubricant
carried with refrigerant returning to compressor 10, and as shown
in FIG. 1 and 2, lubricant level 166 is substantially lower than
lubricant levels 118 in discharge chambers 32 and 36. Referring to
FIGS. 5-8, and 10, it can be seen that front and rear main bearings
20, 22 are provided with suction ports 168, 170, respectively,
which extend axially therethrough (FIG. 10). Normally, suction
chamber lubricant level 166 is below suction ports 168, 170 but may
be above lubricant inlet bores 172, 174, provided in respective
main bearing surfaces 40, 42. Bores 172, 174 extend axially from
respective surfaces 40, 42 into web portion 175 of the main
bearings, in which they terminate without projecting through to
axial surfaces 34, 38 thereof. Referring to FIG. 10, radial
conduits 176, 178 are provided in the peripheral edges of main
bearings 20, 22 to fluidly connect lubricant intake bores 172, 174
with suction ports 168, 170. The peripheral openings of conduits
176, 178 are sealed upon assembly and welding of housing portions
14, 18 to main bearings 20, 22.
[0080] Suction ports 168, 170 communicate with suction port 180 in
cylinder block 76 which can be seen in FIGS. 4 and 11. Like
cylindrical cavity 80, suction port 180 extends axially between the
surfaces 82 and 84 of cylinder block 76, and communicates directly
with cavity 80 through suction inlet 182. As suction gas flows from
suction chamber 44 into suction port 180 through ports 168, 170, it
may aspirate oil from chamber 44 through lubricant intake apertures
172, 174 and bores 176, 178 into suction port 180, if level 166 is
above the height of apertures 172, 174, thus scavenging oil from
the suction chamber. This scavenged oil is carried by the
refrigerant into cavity 80, which comprises the compression chamber
of compressor mechanisms 24, 26, and delivered therethrough to
discharge chambers 32, 36.
[0081] In cylinder block 76, adjacent suction inlet 182 is a
vertically oriented channel or vane slot 184 which extends the
width of the cylinder block between surface 82 and surface 84 and
has generally parallel side walls 186, 188 (FIG. 11). Vane 138 is
disposed in vane slot 184 and vertically reciprocates therein as
its tip 136 follows outside surface 135 of roller piston 132, with
one of vane surfaces 156, 158 adjacent vane slot sidewall 186, the
opposite vane surface adjacent vane slot sidewall 188. Vane 138 may
be a sintered powder metal part, the tolerances between its
opposite planar surfaces 156, 158 and its opposite edges 160, 162
closely controlled. Cylinder block 76 may be manufactured from
individually cast blanks which have been machined or they may be
sintered powder metal parts. Alternatively, an axially elongate
"loaf" of uniform cross section may be produced by casting, powder
metal techniques or extrusion, which is then sawed into individual
cylinder blocks of appropriate thickness and machined.
[0082] An "off the shelf" cylinder block, including an inwardly
tapered vane slot (FIG. 50), has a vane slot width less than the
vane and requires a force being exerted, proximate to the vane slot
walls, to force them apart to receive the vane. In order to provide
proper clearances between vane slot sidewalls 186 and 188 and the
adjacent vane surfaces 156, 158, a process of assembling a rotary
compressor according to the present invention includes the steps
of: forcing apart vane slot walls 186 and 188 slightly; providing a
dummy vane or gauge vane (FIGS. 51 and 54) having generally the
same shape as vane 138 except being about 0.0020 inch thicker
between its opposite planar surfaces in vane slot 184; allowing
vane slot walls 186, 188 to resiliently come into contact with the
planar sides of the gauge vane; assembling the main bearing,
cylinder block and outboard bearing together about the
shaft/eccentric/piston assembly; placing and torquing bolts 90 to
appropriate levels to compress cylinder block 76 between the
bearings, thereby establishing sufficient frictional contact
between the abutting axial surfaces of the bearings and the
cylinder block to hold vane slot walls 186, 188 at their current
spacing; and removing the gauge vane and substituting therefor vane
138, which will have approximately 0.0020 inch clearance between
one of its planar sides 156, 158 and its adjacent vane slot
sidewall.
[0083] An alternative to the inwardly tapered vane slotted cylinder
block, as hereinabove described, is an "off the shelf" cylinder
block including an outwardly tapered vane slot (FIG. 53), having a
vane slot width greater than the vane and requiring a force being
exerted, proximate to the vane slot walls, to force them together
to support the vane. A method of decreasing the width of vane slot
184 to provide a suitable clearance between the vane 138 and vane
slot 184 may be employed. In order to provide proper clearances
between vane slot sidewalls 186 and 188 and the adjacent vane
surfaces 156, 158, a process of assembling a rotary compressor
according to the present invention includes the steps of: providing
the gauge vane having generally the same shape as vane 138 except
being about 0.0020 inch thicker between its opposite planar
surfaces in vane slot 184; decreasing the width of the vane slot
184 by forcing the vane slot walls 186 and 188 slightly together to
frictionally hold the gauge vane therebetween; applying an inward
force to the vane slot walls 186, 188 to come into contact with the
planar sides of the gauge vane; assembling the main bearing,
cylinder block and outboard bearing together about the
shaft/eccentric/piston assembly; placing and torquing bolts 90 to
appropriate levels to compress cylinder block 76 between the
bearings, thereby establishing sufficient frictional contact
between the abutting axial surfaces of the bearings and the
cylinder block to hold vane slot walls 186, 188 at their current
spacing; and removing the gauge vane and substituting therefor vane
138, which will have approximately 0.0020 inch clearance between
one of its planar sides 156, 158 and its adjacent vane slot
sidewall.
[0084] Referring now to FIGS. 50-55, model cylinder blocks are
disclosed, functionally appertaining to all the cylinder blocks
disclosed herein, however, simplified to aid in the explanation of
the relationship between the vane slot and the cylinder block of
the present invention compressor assembly. Referring now to FIG.
50, shown is a model cylinder block 76a having a cylindrical cavity
80a defined by a cylinder wall 81a. Also shown is tapered vane slot
184a cut all the way through the cylinder wall 81a and extending to
an outer periphery 78a of the model cylinder block 76a. The taper
in tapered slot 184a has been exaggerated for clarity. Vane slot
184a is defined by a pair of vane slot sidewalls 186a and 188a,
respectively, and further includes a first vane slot opening 189a,
proximate to the outer periphery 78a of the model cylinder block
76a, and a second vane slot opening 191a, which is proximate to the
cylinder wall 81a within the cylindrical cavity 80a. FIG. 50 shows
tapered vane slot 184a having the first vane slot opening 189a,
which is relatively narrower than the second vane slot opening
191a, for reasons further described below.
[0085] FIG. 51 discloses the insertion of a gauge vane showing the
model cylinder block 76a of FIG. 50, having a pair of equal and
opposing forces 193 imparted on extended portions 185a of the
cylinder block to elastically spread apart the vane slot sidewalls
186a and 188a, respectively. A gauge vane 138g has been inserted
between the vane slot sidewalls 186a, 188a and is shown holding the
vane slot sidewalls 186a, 188a apart, and substantially parallel.
The gauge vane 138g has first and second ends 139 and 140,
respectively, wherein the first end 139 of gauge vane 138g has a
tapered contour so that the gauge vane may be forcefully wedged
into the first vane slot opening 189, which acts similar to forces
193 spreading apart the vane slot sidewalls 186a, 188a, to fit the
vane therebetween. With the gauge vane 138g in place and having
vane slot sidewalls 186a and 188a, respectively, in contact with
the gauge vane 138g, a state of stress develops in cylinder block
portions 197a and is represented by arrows 195. The state of stress
195 is circumferentially oriented about the cylinder block 76a and
is disposed within cylinder block portions 19a, which are located
immediately adjacent cylinder wall 81a, and continue
circumferentially about the cylinder block 76a. The state of stress
195 is tensile in nature and circumferentially orients therealong a
substantial portion of cylinder block portions 19a. State of stress
195 is caused by the spreading apart of vane slot sidewalls 186a
and 188a, respectively, and once created, the cylinder block 76a is
secured by bolting or the like to an adjoining bearing or bearings,
to preserve the stresses within cylinder block portions 19a. Thus,
once the gauge vane 138g is removed the state of stress 195 remains
preserved therein, as hereinafter described.
[0086] Referring to FIG. 52, the model cylinder block 76a is shown
having preserved the circumferentially oriented stress, as shown by
arrows 195, however, the gauge vane 138g has been removed and
replaced by vane 138a. FIG. 52 shows, albeit exaggeratedly, a vane
slot width "S" being preserved, with gauge vane 138g removed, and
the state of circumferentially oriented stress 195 remaining
preserved therein. The vane 138a, having a width or thickness "T",
is freely reciprocatable within vane slot width "S", the width
between "S" and "T" defines a clearance. In order for vane 138a to
reciprocate within vane slot width "S" the clearance must be
suitable, however, an excessive clearance leads to premature vane
wear, and additionally, inefficient compressor mechanism operation
due to refrigerant gas blow-by through the clearance.
[0087] Referring now to FIGS. 53-55, similar to FIGS. 50-52, a
simplified cylinder block is shown, however the cylinder block has
a closeable vane slot. Referring now to FIG. 53, shown is a model
cylinder block 76b having a cylindrical cavity 80b defined by a
cylinder wall 81b. Tapered vane slot 184b is cut all the way
through the cylinder wall 81b and extends to an outer periphery 78b
of the model cylinder block 76b. The taper in tapered slot 184b has
been exaggerated for clarity. Vane slot 184b is defined by a pair
of vane slot sidewalls 186b and 188b, respectively and further
includes a first vane slot opening 189b, proximate to the outer
periphery 78b of the model cylinder block 76b, and a second vane
slot opening 191b, which is proximate to the cylinder wall 81b
within the cylindrical cavity 80b. FIG. 53 shows tapered vane slot
184b, having the first vane slot opening 189b, which is relatively
broader than the second vane slot opening 191b, for reasons further
described below.
[0088] FIG. 54 represents the gauge vane insertion or vane slot
setting step of the inventive method, showing the model cylinder
block 76b of FIG. 53, having a pair of equal and opposing forces
199 imparted on extended portions 185b of the cylinder block 76b
elastically closing together the vane slot sidewalls 186b and 188b,
respectively. A gauge vane 138g has been inserted between the vane
slot sidewalls 186b, 188b and is shown contacting vane slot
sidewalls 186b, 188b to provide a substantially parallel slot.
Gauge vane 138g used on cylinder block 76a, may also be utilized on
cylinder block 76b in providing a standard in which to set the vane
slot. With the gauge vane 138g in place and having vane slot
sidewalls 186b and 188b, respectively, in contact with the gauge
vane 138g, a circumferentially oriented state of stress 201
develops in cylinder block portions 197b, which are located
immediately adjacent cylinder wall 81b. The cylinder block portions
197b are circumferentially continuous about the cylinder wall 81b.
The circumferentially oriented state of stress 201 is compressive
in nature, for a substantial portion of cylinder block portions
197b about the cylinder wall 81b. State of stress 201 is caused by
the closing together of vane slot sidewalls 186b and 188b,
respectively, and once the stress 201 is created, the cylinder
block 76 is thereafter secured by bolting or the like to an
adjoining bearing or bearings, to preserve the stresses within the
cylinder block portions 197b. Thus, subsequent to the gauge vane
138g being removed the state of stress 201 is preserved therein, as
hereinafter described.
[0089] Referring to FIG. 55, the model cylinder block 76b is shown
having the gauge vane 138g removed and the gauge vane width "S"
preserved. Also preserved is the circumferentially oriented
compression stress 201. FIG. 55 shows the vane 138g in the vane
slot 184b. The vane 138b having a width or thickness "T" is freely
reciprocatable within vane slot width "S" and the width between "S"
and "T" defines a clearance. In order for vane 138a to reciprocate
within vane slot width "S" the clearance must be suitable, however,
an excessive clearance leads to excessive vane wear and
malfunction. Also an excessive clearance coincides with inefficient
compressor operation due to refrigerant gas blow-by through the
clearance.
[0090] As mentioned above, during the step of increasing the width
"S" of the vane slot 184a, cylinder block portions 197a develop a
state of circumferentially oriented tensile stress 195, which is
preserved once the cylinder block 76a is clamped between outboard
bearings 88, 100 and main bearings 20, 22. In contrast, during the
step of decreasing the width "S" of the vane slot 184b, cylinder
block portions 197b develop a state of circumferentially oriented
compressive stress 201, which is preserved once the cylinder block
is clamped between outboard bearings 88, 100 and main bearings 20,
22. Generally, pre-stressing portions of the cylinder block 76, as
hereinabove explained, results in offsetting dynamic forces
imparted on the cylinder block 76 by the rotating roller piston
132, to enhance wear resistance and longevity of the cylinder block
76. Furthermore, the tapered vane slotted cylinder block requires
fewer machining operations and costly machining operations may be
avoided.
[0091] Referring now to FIGS. 1, 2 and 4, and more specifically the
liquid lubrication of the vane and vane slot, each liquid lubricant
pool having surface level 118 in discharge chambers 32, 36 is of
sufficient height to immerse vane 138 in the pool of lubricant.
Immersion of vane 138 in the lubricant seals the clearance between
vane 138, the sidewalls of vane slot 184 and the adjacent axial
bearing surfaces against refrigerant blow-by from the compression
chamber, as well as lubricates the vane surfaces.
[0092] Referring again to FIG. 4, it can be seen that cylindrical
discharge opening 190 is provided in the cylindrical wall of cavity
80 adjacent vane slot 184, on the opposite side thereof from inlet
opening 182. By providing cylindrical discharge opening 190 in the
wall of cavity 80 adjacent vane slot 184, rather than in the axial
surface of the outboard bearing, an outlet port of unchanging area
is provided for discharge gases to be exhausted from the
compression chamber throughout the compression cycle, regardless of
the roller piston position. Adjacent and downstream of cylindrical
discharge opening 190 is frustoconical valve seat 192 on which the
mating frustoconical surface of head 194 of poppet 196 seals.
Poppet head 194 is urged into sealing contact with surface 192 by
compression spring 198 disposed about poppet shaft 200. One end of
spring 198 abuts the underside of poppet head 194; its opposite end
abuts disc 202, which is cushioned by neoprene cushion 204 and
disposed in pocket 206 of poppet retainer 208. Retainer 208 limits
the radial travel of poppet 196 away from seat 192 to about 1/8
inch, the terminal end of poppet shaft 200 opposite head 194
abutting disc 202 at the furthest extent of poppet travel. Neoprene
cushion 204 softens the impact of the poppet shaft end against disc
202, thereby quieting the operation of the compressor. Poppet 196
prevents previously exhausted discharge pressure gases from
reentering the compression chamber, where they would otherwise be
recompressed, undermining the efficiency of the compressor. Poppet
196 is preferably made of a durable yet lightweight material, for
example a plastic such as Vespel.TM., as may retainer 208. Disc 202
may be plastic or metal.
[0093] Retainer 208 is provided in radially extending cylinder
block bore 210 and maintained in position therein by means of pin
212 extending through a pair of holes 214 provided on opposite
axial sides of bore 210. Pin 212 is prevented from moving axially
within holes 214 by its ends abutting the adjacent axial surfaces
of the main and outboard bearings. Discharge gases compressed in
the compression chamber urge poppet 196 off its seat 192 against
the force of spring 198 and flow past poppet head 194 into
discharge cavity 216 provided in cylinder block 76. Poppet 196 is
urged by spring 198 back into sealing engagement with seat 192 once
the discharge pressure gas has exited the compression chamber
through opening 190, preventing the expelled gas from flowing back
into the compression chamber.
[0094] Discharge cavity 216 extends axially between cylinder block
surfaces 82, 84, and is defined by cavity surface 217 and the
adjacent axial surfaces of the main and outboard bearings. Cavity
216 serves to attenuate gas-borne noises and pressure pulses
arising from operation of the compressor. As shown in FIG. 4,
discharge gases exit cavity 216 by means of discharge port 218
provided in outboard bearing 100 (and through corresponding port
220 in front outboard bearing 88, FIG. 12). Discharge gases
expelled from cylinder block discharge cavity 216 through discharge
ports 218, 220 enter respective discharge chambers 32 and 36. Those
of ordinary skill in the art will appreciate that discharge
chambers 32 and 36 serve as mufflers as well, attenuating gas-borne
noises and pressure pulses before discharge pressure refrigerant
exits compressor assembly 10 through discharge conduit or tube 118.
Furthermore, each compressor mechanism 24, 26, respectively, draws
refrigerant gases from the suction chamber 44 and discharges the
compressed gases into the discharge chambers 32, 36 respectively,
to further attenuate sources of fluid borne noise and vibration
which would be otherwise carried by suction conduits, discharge
conduits and the like, rigidly connecting the housing to the
compressor mechanisms.
[0095] As shown in FIGS. 13 and 15, outboard bearings 88 and 100
are provided with conduits 222 and 224 which respectively extend
from inlets 226, 228 to outlets 230, 232. Inlets 226 and 228 are
provided proximate the terminal ends of shaft 52 in respective
bearing hub portions 234, 236; outlets 230, 232 open onto
respective axial surfaces 86, 98 into regions of the compression
chambers which are at a pressure intermediate suction and discharge
pressure (FIG. 4). The outboard axial surfaces of roller pistons
132 cover and block outlets 230, 232 as the roller pistons reach
orientations about the cylindrical surfaces of cavities 80 normally
corresponding to pressures at and above which oil, which is
approximately at discharge pressure, may be forced to reversibly
flow backwards through conduits 222, 224. Referring to FIG. 1, it
can be seen that front outboard bearing hub portion 234 is provided
with oil diverter cap 238, which may be made of sheet metal. Cap
238 directs oil received from shaft bore 110 and directs it towards
inlet 226 of conduit 222. Through conduit 222 oil is provided to
the compression chamber of the front compressor mechanism,
lubricating exposed surfaces therein. Similarly, hub 236 of rear
outboard bearing 100 is provided with cap 240 enclosing a portion
of pump 112 and which may also be made of sheet metal. Cap 240 is
provided with an central aperture through which lubricant draw
conduit or tube 114 is fitted. Cap 240 directs lubricant received
from lubricant tube 114 upstream of pump 112 through inlet 228 of
conduit 224.
[0096] FIGS. 16A through 16C detail the shaft 52. As seen in FIG.
16B and 16C, at the point of respective small diameter shaft
portions 60 and 58 about which eccentrics 122 are attached thereto.
FIG. 16B shows that shaft portion 60 is provided with crossbore 242
which extends through the diameter of shaft portion 60 intersecting
axial bore 110. FIG. 16C shows that shaft portion 58 is provided
with similar crossbore 244. Referring now to FIGS. 17A and 17B,
there is shown cross-sectional views of eccentric 122, which as
discussed above is attached to the shaft 52 at countersinks 130
provided in shaft portions 58 and 60. Eccentric 122 is provided
with axial bore 246 having centerline 248 offset and parallel to
axis 250 of shaft 52 (FIG. 16A). Eccentric 122 is provided with
crossbore 252 which extends through eccentric bore 246 to a second
axial bore 254 extending between the axial surfaces of the
eccentric. With eccentric 122 assembled to shaft portions 58, 60,
eccentric crossbore 252 is brought into alignment with shaft
crossbores 244 and 242. Because one end of crossbore 252 opens to
outside surface 134 of the eccentric, oil provided through bore 110
to aligned bores 242, 252 and 244, 252 lubricates the interfacing
cylindrical surfaces 133 and 134 between roller piston 132 and
eccentric 122. The opposite end of crossbore 252 extends into axial
eccentric bore 254, providing oil received from shaft bore 110
axially into the forward and rear spaces provided between the
eccentric axial surfaces and the adjacent axial surfaces of the
main and outboard bearings, these spaces inside surface 133 of
roller piston 132; during normal compressor operation, these spaces
are filled with oil.
[0097] Referring now to FIG. 18, there is shown compressor assembly
10', a second embodiment according to the present invention.
Compressor 10' is for the most part identical with compressor
assembly 10, except is adapted to be vertically oriented. Thus with
respect to the preceding discussion, the forward compressor
mechanism 24 is, in this second embodiment, referred to as upper
compressor mechanism 24'. Similarly, with respect to the preceding
discussion, rear compressor mechanism 26 is now lower compressor
mechanism 26'. All previously discussed components of compressor
assembly 10 are configured and carried over into compressor
assembly 10' in the same way except as distinguished
hereinbelow.
[0098] Compressor assembly 10', being vertically oriented, has a
pair of pools of liquid lubricant having levels 118' in each of its
discharge chambers 32, 36. The level of lubricant or oil 118' in
upper discharge chamber 32 is, in normal operation of compressor
assembly 10', above axial surface 86 of upper outboard bearing 88'.
Thus vane 138 of upper compressor mechanism 24' is, as described
with respect to front and rear compressor mechanisms 24, 26 of
compressor assembly 10, immersed in oil. Oil may initially collect
in the lower portion of suction chamber 44, as shown in FIG. 18
having level 166', however, the oil eventually aspirates through
the suction port 170 (FIGS. 7 and 8), and commonly exhibits a
negligible level therein. As described above, oil will be scavenged
from chamber 44 through aperture 174 in lower main bearing 22.
Aperture 172 of upper main bearing 20 will draw suction pressure
gas into port 168 instead of oil. As best seen in FIG. 19, oil draw
tube 114' extends downwardly from cap 240 to provide access to the
oil in the lower portion of chamber 36. Compressor assembly 10'
employs the same lubrication methods as described above, with the
except that, because vane 138 of lower compressor mechanism 26'
cannot be immersed in oil, additional lubrication providing means
is provided. Referring to FIG. 21, there is shown cylinder block
76' which is identical to cylinder block 76 with the exception that
sidewalls 186, 188 of vane slot 184 are provided with scallops 256,
258, respectively. These scallops have the shape of a circle
segment and, as will be described further below, allow oil to be
provided adjacent the planar sides of vane 138 in lower compressor
mechanism 26. Referring to FIG. 22, it is seen that lower outboard
bearing 100' is provided with an axially directed through bore 260
of size matching the circle which would be defined by scallops 256
and 258 in cylinder block 76'. Into bore 260 is press fitted second
oil draw conduit or tube 262 which extends from the location
approximate surface 98 of outboard bearing 100' downwardly into the
oil contained in the lower portion of chamber 36. During operation
of compressor assembly 10', as vane 138 reciprocates in compressor
mechanism 26', the oil in chamber 36, which is under discharge
pressure, is drawn through oil draw tube 262 into scallops 256,
258, sealing the gap between vane slot sidewalls 186, 188 and
planar sides 156, 158 of the vane. Thus, it can be seen that oil
forced or drawn upward through tube 262 lubricates and seals vane
138 in vane slot 184. Upper compressor mechanism 24' may utilize a
common cylinder block 76'. Upper outboard bearing 88', may be
provided with bore 264 corresponding to bore 262 in lower outboard
bearing 100' to, perhaps, better facilitate machining operations.
If upper outboard bearing 88' is provided in compressor assembly
10' instead of outboard bearing 88, bore 264 would be plugged to
prevent the ingress of discharge pressure gasses from chamber 32
into scallops 256, 258. Bore 264 would be plugged with plug 266
(FIG. 18).
[0099] Referring to FIG. 24, a third embodiment of the twin rotary
compressor assembly 10" is shown and is similar to the first
embodiment compressor assembly 10 except as identified hereinbelow.
Refrigerant gases, at suction pressure, flow into tube 164" through
filter 165" and into suction chamber 44. Chamber 44, as in the
first embodiment, is the suction chamber wherein the motor assembly
46 is immersed in relatively cool refrigerant gases. Following
introduction into suction chamber 44, refrigerant then flows
through identical suction mufflers 268, fastened to front and rear
main bearings 20", 22" respectively, as shown. Suction mufflers 268
are thin metallic or plastic discs, overlaying axial surface 40" of
the front bearing 20" and surface 42" of the rear bearing 22."
Suction mufflers 268 have collar portions 270, which are slightly
larger in diameter than hubs 68" and 74" to allow refrigerant gases
to pass therebetween. Each suction muffler 268, acts to slow down
the refrigerant gases entering each compressor mechanism to
alleviate and attenuate noise otherwise manifested by free flowing
refrigerant gases. Similar to the operations of the first
embodiment compressor assembly 10, as previously described above,
compressor assembly 10" compresses refrigerant in compressor
assemblies 24" and 26" and discharges the compressed gases into
front discharge chamber 32 and rear discharge chamber 36 through
front and rear outboard bearings 88" and 100", respectively. The
discharge gases carrying fluid-borne noise are muffled by first
housing portion 14" and second housing portion 18". Discharge gases
within chamber 32, as well as discharge gases from chamber 36,
communicate via external cross-over tube 115". The merged discharge
gases are then dispersed through the discharge tube 120" exiting
the housing 12" of the compressor assembly 10".
[0100] The compressor assembly 10" supports shaft 52" at two
locations, namely, a front portion 282 and a rear portion 280. At
the front portion 282 of the shaft 52", the supporting structure
includes the front main bearing 20" wherein the front main bearing
20" includes a bushing 272 which contacts the large diameter
portion 56" of the front portion 282 of the shaft 52". Likewise, at
the rear portion 280 of the shaft 52", the rear main bearing 22"
supports the shaft 52" through rear bushing 274. The shaft 52"
freely rotates within the front and rear bearings, however, endwise
movement of the shaft 52" is restrained by common cover plate 288.
Cover plates 288 mount to the front outboard bearing 88" and the
rear outboard bearing 100", each secured by a pair of screws 292,
to restrain endwise movement of the shaft 52".
[0101] Referring now to FIG. 25, orientation of shaft 52",
eccentric 122" and roller piston 132, and additionally, lubrication
thereof, will now be discussed. The crossbore 252" in eccentric
122" aligns with the crossbore 244" in the front portion 282 of the
shaft 52" to allow oil to flow to the roller piston 132. Oil
travels through bore 286, down the centerline of the shaft 52",
entering crossbore 244" and crossbore 252" of eccentric 122" to
coat the inner surface 133 of the roller piston 132. Eccentric 122"
includes a pair of reliefs 294 along the outer surface 134" of the
eccentric 122" in order to increase oil flow to the inner surface
133 of the roller piston 132 as well as a pair of axial faces 295
of the eccentric 122". Also shown is outboard bearing 88" having an
oil passageway 298, well below oil level 118 so that vane 138"
reciprocating between vane slot surfaces 296 are well saturated in
oil to prevent refrigerant gas blow-by.
[0102] Referring to FIG. 26, the outboard bearing 88" includes a
raised portion 234", the discharge port 220", and the oil
passageway 298. The raised portion 234" of the outboard bearing 88"
also includes threaded holes 300 to fasten cover plates 288
thereto. Oil passage 298 in outboard bearing 88" is shown well
below oil level 118 allowing oil to enter passageway 298 and
generally saturate vane 138" and vane slot 184" in oil. Discharge
port 220" is shown well above oil level 118 so that under normal
operation of the front compressor mechanism 24" oil does not create
a back pressure and refrigerant gases may freely exit discharge
port 220".
[0103] Referring to FIG. 27, within the front compressor mechanism
24" is shown the roller piston 132, the eccentric 122" and the
shaft 52" wherein the eccentric 122" is pinned to the shaft 52".
The rear compressor mechanism 26" involves an identical
configuration in that the eccentric 122" is thereby pinned to the
shaft 52". Momentarily referring to FIG. 42, there is seen a groove
306 in the shaft 52" receiving a pin 302 (FIG. 27) and further, as
shown in FIGS. 43-45 there is a groove 34 in the eccentric 122"
that receives the pin 302, thereby securing the eccentric 122" to
the shaft 52".
[0104] Referring again to FIG. 27, and more specifically the area
about vane 138", vane 138" is shown in vane slot 184" and held in
contact with the roller piston 132 by biasing member or spring
142". Spring 142" is restrained within a spring cavity 308 by a
cover 310 and cover 310 is secured by screw 312. Screw 312 is
threaded into hole 314 which is within cylinder block 76". Scallops
256" and 258" can be seen disrupting spring cavity 308 as scallops
256" and 258 are continuous along the width of cylinder block 76".
Cylinder block 76" includes an inner wall 313 defining a portion of
the discharge cavity 216" wherein a reed valve 318 and retainer 320
are secured. Reed valve 318 and retainer 320 operate by allowing
compressed discharge gases to escape the cylindrical cavity 80, and
in addition, to keep discharge gas from flowing back into the
cylindrical cavity 80. The reed valve 318 and the retainer 320 are
secured to the cylinder block 76" by way of a pair of threaded
fasteners 322.
[0105] Referring to FIG. 28, the retainer 320 and the corresponding
reed valve 318 include three individual fingers which correspond
with three discharge openings 316 (FIG. 35). The retainer 320 has a
first end 323 which is secured by fasteners 322 and a second end
325 including the three fingers extending therefrom. The three
fingers of the retainer 320 overlay the three discharge openings
316. Corresponding reed valve is sandwiched between the retainer
320 and inner wall 323. Each finger of the retainer is held away
from the inner wall 313 and acts as a stop for each corresponding
finger of the reed valve 318. Pressure within the cylindrical
cavity 80 increases until the fingers of the reed valve are
displaced and cylinder pressure is alleviated. The fingers of the
reed valve 318 return to their original position overlaying the
inner wall 313 when cylinder chamber pressure is sufficiently
decreased. The retainer 320 may be made of a metallic material or a
suitable rigid, high temperature plastic. The reed valve 318 may be
made of a metallic material or a suitable high temperature polymer.
Also shown in FIG. 28 are a pair of bolt holes 324 which receive
bolts 336 to fasten cylinder block 76" to the front main bearing
20" and the rear main bearing 22".
[0106] Referring now to FIG. 29, outboard bearing 20" includes
control surface 28" which serves as a partition to separate
discharge chamber 32 from suction chamber 44. Main bearing 20"
includes the pair of holes 326 that receive the bolts 336 (not
shown) to fasten the cylinder block 76" to control surface 28" of
the main bearing 20". The main bearing 20" also includes three
threaded holes 331 which receive three threaded fasteners or bolts
90 (not shown) to secure not only the cylinder block 76" but the
outboard bearing as well. Suction port 168" is a continuous hole
through bearing 20" and aligns with the suction portion of cylinder
block 76".
[0107] Referring now to FIG. 30, the side opposing control surface
28" of main bearing 20" is shown including a well portion 328 and
several raised portions thereon. Three distinct and equally
radially displaced raised portions 330 include threaded holes 331
which receive bolts 90 (not shown) to clamp the cylinder block 76"
between the front main bearing 20" and the front outboard bearing
88" (not shown). A pair of raised portions 332 include a first set
of threaded holes 324 to receive bolts 326 in mounting the cylinder
block 76" to the front main bearing 20". A second set of threaded
holes 335 are included in raised portions 332 and receive screws
334 (not shown) to hold the suction muffler 268 thereagainst. The
final raised portion 338 also includes threaded hole 335 to secure
the suction muffler 268 in a third location to the front main
bearing 20". The front main bearing 20" also includes suction port
168" aligning with the suction port 180" of the cylinder block 76"
and bushing 272, within the center portion of front main bearing
20" and supporting shaft 52".
[0108] Referring to FIG. 31 and front main bearing 20" in FIG. 29,
rear main bearing 22" is a mirror image of 20". Rear main bearing
22" includes a control surface 29" which encloses discharge chamber
36 and separates discharge chamber 36 from suction chamber 44. Rear
main bearing 22" includes a pair of threaded holes 326 to secure
cylinder block 76", and in addition, three threaded holes 331 which
fasten the rear outboard bearing 100" to the rear main bearing 22"
sandwiching the cylinder block 76" therebetween. The rear main
bearing 22" also includes a hole therethrough 170" aligned within
suction port 180" of cylinder block 76" to allow suction gases
within chamber 44 to enter cylinder block 76" in the rear
compressor mechanism 26". Referring now to FIG. 32, the rear main
bearing 22" is a mirror image of front main bearing 20", as shown
in FIG. 30, and its `structure` and operation is similar thereto.
Referring now to FIG. 33, rear main bearing 22" includes through
holes 331 to receive bolts 90 (not shown) fastening rear outboard
bearing 100" to rear main bearing 22". A second hole 335 is shown,
which does not continue through the width of the rear main bearing
22". A portion of hole 335 is threaded to receive a fastener 334 to
secure the suction muffler 268 to the axial surface 42" of rear
main bearing 22".
[0109] Referring now to FIG. 34, a common cylinder block 76" of the
third embodiment is shown. The vane slot 184" includes an upper
portion 340 and a lower portion 342. The upper portion 340 of the
vane slot 184" includes the surfaces 296 contacting the vane 138",
whereas during compressor assembly 10" operation, the lower portion
342 of the vane slot 184" does not contact vane 138". The upper
portion 340 of the vane slot 184" is separated from the lower
portion 342 by scallops 256" and 258", respectively. Cylinder block
76" includes holes 94 which facilitate outboard bearing bolts 90
(not shown) and additionally, holes 324 to facilitate cylinder
block screws 334 (not shown).
[0110] Referring to FIG. 35, cylinder block 76" includes the inner
wall 313 partially defining the discharge cavity 216" which
accommodates the retainer 320 and reed valve 318. More
specifically, a pair of holes 344 include threads which receive a
pair of screws 322 (FIG. 28) to secure the retainer 320 and reed
valve 318. Also, within inner wall 313 are three discharge openings
316 which fluidly connect discharge cavity 216" to cylindrical
cavity 80. Discharge openings 316 in inner wall 313 are overlayed
by the three fingers of the reed valve 318 (FIG. 28). Cylinder
block 76" also includes a spring cavity having a suitable depth to
receive an adequate sized spring, such as spring 142" (FIG. 27),
however leaving enough cylinder block material to form an
adequately supportive vane slot for the vane 138".
[0111] Referring to FIGS. 36-38, there is shown the front outboard
bearing 88" and more specifically the oil conduit 224" contained
therein. FIG. 37 displays oil conduit 224" having a conduit inlet
226" at chamfer 346 extending diagonally through the width of the
outboard bearing 88", and exiting at conduit outlet 230" of the
axial surface 86". Conduit outlet 230" is positioned within an
interior portion of the cylindrical cavity 80 to expose front
portion 282 of shaft 52" to a lower pressure than rear portion 280
of shaft 52". This pressure difference acts to draw oil from rear
portion 280 of shaft 52" to front portion of shaft 52" through
bores 284 and 286, respectively (FIG. 24). This "rear to front"
migration of oil through shaft 52" ensures oil is introduced into
cylindrical cavities 80 for proper lubrication of the roller piston
132" and surfaces defining the cylindrical cavity 80. FIG. 38
displays the pair of holes 300 which threadably receive screws 292
to secure cover plate 282 in restraining endwise movement of shaft
52".
[0112] Referring to FIG. 39, rear outboard bearing 100" is shown
with the oil pump assembly 112". Rear outboard bearing 100"
includes two through holes: the oil passageway 298 and discharge
port 218". Referring now to FIGS. 40-42, shaft 52" includes the
front portion 282 and the rear portion 280 coinciding with the
front and rear ends of the compressor assembly 10". A center
portion of the shaft includes a surface 56" which is in rotational
contact with the front bushing 276 and the rear bushing 278. On
shaft 52" are a pair of O-ring grooves 276 and 278, respectively,
which receive O-rings (not shown). O-ring grooves 276 and 278,
respectively, serve to separate the suction chamber pressure within
suction chamber 44 from the discharge chamber pressure in front
chamber 32 and rear discharge chamber pressure in rear chamber 36.
Shaft 52" includes a large diameter inner bore 286 and a somewhat
smaller bore 284 extending through the rear portion 280 of the
shaft 52". Cross bore 242" allows oil, being drawn from the rear
portion 280 of the shaft, into eccentric 122", similarly, cross
bore 244" allows oil being drawn from the rear portion 280 of the
shaft 52" and into eccentric 122" positioned at the front portion
282 of the shaft 52".
[0113] Referring to FIG. 41, crossbore 242" is shown intersecting
through bore 284 to facilitate the migration of oil into eccentric
122". Also shown is surface 60" including a disruption thereon in
the form of a pin groove 350. Referring to FIG. 42, the front
portion 282 of the shaft 52"includes outer surface 56", front small
diameter portion 58" and pin groove 306 thereon. Crossbore 244"
intersects inner bore 286 to welcome oil migration into the
eccentric 122" attached thereto (not shown).
[0114] Referring now to FIGS. 43-45, eccentric 122" includes a pair
of reliefs 294 and inner bore 246" formed continuously through and
a pin groove 304 therealong. During operation of the compressor
10", oil moves through passageway 252" towards the outer surface
134" of eccentric 122" coating the outer surface 134" as well as
the inner surface 133 of the roller piston 132. The pair of reliefs
294 facilitate optimum lubrication of axial faces 295 of the
eccentric 122".
[0115] Referring now to FIG. 46, a fourth embodiment of the
compressor assembly 10'" of the present invention is shown and is
similar in many aspects to the third embodiment 10", however,
vertically oriented. The compressor assembly 10'" includes a lower
compressor mechanism 26'" having an oil suction tube 262" sealably
fitting into an oil passageway 353 in lower outboard bearing 100"
to draw from oil level 118" and lubricate the vane 138'". Also
included in this particular embodiment is an elbowed pump intake
conduit in the form of a tube 354 within the oil pump assembly
112'" to draw oil vertically and into the lower portion 280 of the
shaft 52'". The oil level in the upper discharge chamber, nearing
the discharge port, becomes an undesirous source of backpressure if
such level exceeds the discharge port, however, nonetheless
depicted to set forth that the reed valve, within the cylinder
block, may suffice as an oil barrier to block excessive amounts of
oil attempting to enter the cylindrical cavity via the discharge
port.
[0116] Referring to FIG. 47, yet another embodiment, the fifth
embodiment of the present invention compressor assembly 10"",
discloses a cascaded compressor assembly, or series configuration,
such that general operation can be described as follows: a first
compressor mechanism 24"" compresses refrigerant gas to an
intermediate pressure stage and discharges such pressurized gas to
a second compressor 26"", via an suction tube 356, wherein the
final discharge pressure is obtained. More specifically,
refrigerant gas is introduced at a suction pressure within suction
chamber 44 and thereafter is suctioned into front compressor 24"",
exclusively. The gas at suction pressure is then compressed to an
intermediate pressure and dispersed within discharge chamber 32.
Thereafter, the refrigerant gas at intermediate suction pressure
and within discharge chamber 32 is extended through suction tube
356. Suction tube 356 is in exclusive communication with an suction
port 358 located on an axial surface 359 of the outboard bearing
100"" of the rear compressor mechanism 26"". The intermediate stage
refrigerant gas, supplied to compressor 26"" by suction tube 356,
is further compressed and discharged into discharge chamber 36. The
discharged refrigerant, at the secondary or maximum pressure,
within chamber 36 exits the compressor housing 12"" through
discharge tube 120"". Suction tube 356 may enter compressor
mechanism 26"" through the center portion of the housing 12"", as
shown, however, the suction tube 356 entering the respective end
portion of the housing 12"" may
[0117] Referring to FIG. 48, the rear outboard bearing 100"" has an
suction port 358, sealably receiving the suction tube 356, the oil
passageway 298"" and the discharge port 218"". Once again, oil
level 118"" substantially covers the vane 138"" and vane slot 134""
(see also FIG. 47). However, it can be seen care is taken to avoid
oil level to reach discharge port 218"". Suction port 358 seals
around suction tube 356 therefore an oil level 118"" substantially
thereover the suction port 358 will not hinder operation of the
compressor assembly 10"" whatsoever. Referring to FIG. 49, main
bearing 22"" has control surface 29"" with cylinder block 76""
attached thereto. However, in contrast to the previously
hereinabove described compressor assembly embodiments, compressor
assembly 10"" includes the main bearing 22"" which does not fluidly
communicate with the suction chamber 44.
[0118] While this invention has been described as having exemplary
designs, the present invention may be further modified within the
spirit and scope of this disclosure. Therefore, this application is
intended to cover any variations, uses, or adaptations of the
invention using its general principles. For example, aspects of the
present invention may be applied to single cylinder rotary
compressors. Further, this application is intended to cover such
departures from the present disclosure as come within known or
customary practice in the art to which this invention pertains.
* * * * *