U.S. patent application number 10/675313 was filed with the patent office on 2004-10-21 for terminal block assembly for a hermetic compressor.
Invention is credited to Skinner, Robin G., Wright, Ryan M., Yap, Zer Kai.
Application Number | 20040208760 10/675313 |
Document ID | / |
Family ID | 33158678 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040208760 |
Kind Code |
A1 |
Yap, Zer Kai ; et
al. |
October 21, 2004 |
Terminal block assembly for a hermetic compressor
Abstract
A hermetic compressor assembly that includes a hermetically
sealed housing. A motor and compressor mechanism are disposed
within the housing. The housing wall includes an aperture and a
terminal block is mounted on the housing wall proximate the
aperature. The terminal block forms a hermetic seal with the
exterior surface of the housing wall that encircles the aperture.
The seal may be formed by welding the terminal block to the
exterior housing wall surface and the terminal block may be
positioned entirely outwardly of the exterior surface of the
housing wall and have a concave surface for engaging the housing
wall. A cover may also be provided wherein the cover has a
plurality of radially inwardly projecting tabs that are engageable
with a latching surface on the terminal body. The latching surface
may be formed by an annular groove formed in the terminal body.
Inventors: |
Yap, Zer Kai; (Tecumseh,
MI) ; Skinner, Robin G.; (Tecumseh, MI) ;
Wright, Ryan M.; (Tecumseh, MI) |
Correspondence
Address: |
BAKER & DANIELS
111 E. WAYNE STREET
SUITE 800
FORT WAYNE
IN
46802
|
Family ID: |
33158678 |
Appl. No.: |
10/675313 |
Filed: |
September 30, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10675313 |
Sep 30, 2003 |
|
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|
10414332 |
Apr 15, 2003 |
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Current U.S.
Class: |
417/410.3 |
Current CPC
Class: |
F04C 2230/231 20130101;
F04C 2230/60 20130101; Y10S 417/902 20130101; F04C 29/0085
20130101; F04B 39/121 20130101; F04C 23/008 20130101; H02K 5/225
20130101; F01C 21/10 20130101; F04C 18/3562 20130101 |
Class at
Publication: |
417/410.3 |
International
Class: |
F04B 035/04 |
Claims
What is claimed is:
1. An assembly for use with a hermetic compressor, said assembly
comprising: a hermetically sealed housing defining an interior
space and including a housing wall with an interior surface and an
exterior surface, said housing wall defining an aperture extending
through said housing wall and communicating with said interior
space; a motor and a compressor mechanism operably coupled with
said motor disposed within said interior space; a terminal block
mounted on said housing wall proximate said aperture and forming a
hermetic seal with said exterior surface of said housing wall, said
hermetic seal encircling said aperture; and at least one terminal
pin mounted in said terminal block and extending through said
aperture.
2. The hermetic compressor assembly of claim 1 wherein said
terminal block includes a mating surface flushly engaged with said
exterior surface of said housing wall and encircling said
aperture.
3. The hermetic compressor assembly of claim 2 wherein said
exterior surface is cylindrical and said mating surface is a
concave surface.
4. The hermetic compressor assembly of claim 1 wherein said at
least one terminal pin comprises a terminal pin assembly
threadingly engaging a threaded opening defined by said terminal
block.
5. The hermetic compressor assembly of claim 1 wherein said at
least one terminal pin has an outwardly projecting end and said
assembly further comprises a cover securable to said terminal block
wherein said cover defines an enclosure for said outwardly
projecting end of said at least one terminal pin when said cover is
secured to said terminal block and wherein said terminal block
includes a latching surface securably engageable with said
cover.
6. The hermetic compressor assembly of claim 5 wherein said
latching surface is defined by a groove formed in said terminal
block.
7. The hermetic compressor assembly of claim 5 wherein said cover
includes at least one resilient mounting member engageable with
said latching surface to secure said cover to said terminal
block.
8. The hermetic compressor assembly of claim 7 wherein said at
least one mounting member includes a radially inwardly extending
tab engageable with said latching surface.
9. The hermetic compressor assembly of claim 7 wherein said
terminal block includes a guide surface disposed between said
latching surface and a distal end of said terminal block, said
guide surface tapering radially inwardly as said guide surface
projects from said latching surface toward said distal end.
10. The assembly of claim 1 wherein said terminal block is disposed
entirely outwardly of said exterior surface of said housing
wall.
11. The assembly of claim 1 wherein said terminal block includes a
portion disposed within said aperture.
12. The assembly of claim 1 wherein said terminal block is welded
to said exterior surface of said housing wall.
13. A hermetic compressor assembly, said assembly comprising: a
hermetically sealed housing defining an interior space and
including a housing wall with an interior surface and an exterior
surface, said housing wall defining an aperture extending through
the wall and in communication with said interior space; a motor and
a compressor mechanism operably coupled with said motor disposed
within said interior space; a terminal block mounted on said
housing covering said aperture and forming a hermetic seal with
said housing wall, said terminal block defining an annular groove;
at least one terminal pin extending through said terminal block and
having an end projecting outwardly from said terminal block; and a
cover having a plurality of radially inwardly projecting tabs
engageable with said groove to thereby mount said cover to said
terminal block with said cover substantially enclosing said
outwardly projecting end of said at least one terminal pin.
14. The hermetic compressor assembly of claim 13 wherein said cover
includes a plurality of resilient mounting members extending
therefrom and said tabs are disposed on respective distal ends of
said plurality of resilient mounting members.
15. The hermetic compressor assembly of claim 13 wherein said
terminal block includes a guide surface disposed between said
annular groove and a distal end of said terminal block, said guide
surface tapering radially inwardly as said guide surface projects
from said latching surface to said distal end.
16. The hermetic compressor assembly of claim 15 wherein said guide
surface forms a frustroconical shape.
17. A hermetic compressor assembly, said assembly comprising: a
hermetically sealed housing defining an interior space and
including a housing wall having an interior surface and an exterior
surface, said housing wall defining an aperture in communication
with said interior space; a motor and a compressor mechanism
operably coupled with said motor disposed within said interior
space; a terminal block positioned over said aperture and welded to
said exterior surface of said housing at a location spaced radially
outwardly of said aperture; and at least one terminal pin mounted
in said terminal block and extending through said aperture.
18. The hermetic compressor assembly of claim 17 wherein said
terminal block is disposed entirely outwardly of said exterior
surface of said housing wall.
19. The hermetic compressor assembly of claim 17 wherein said
terminal block includes a portion disposed within said
aperture.
20. The hermetic compressor assembly of claim 17 wherein said
terminal block forms a hermetic seal with said exterior surface of
housing wall, said hermetic seal encircling said aperture.
21. The hermetic compressor assembly of claim 17 wherein said
exterior surface of said housing wall has a cylindrical shape and
said terminal block defines a concave surface flushly engageable
with said exterior surface.
22. A method of assembling a hermetic compressor comprising:
providing a housing having a housing wall with an interior surface
and an exterior surface; forming an aperture in the housing wall;
installing at least one terminal pin in a terminal block; mounting
the terminal block on the housing wherein the terminal block covers
the aperture; and forming a hermetic seal between the terminal
block and the exterior surface of the housing wall wherein said
hermetic seal circumscribes the aperture.
23. The method of claim 22 wherein the steps of mounting the
terminal block to the housing and forming the hermetic seal between
the terminal block and the exterior surface of the housing wall
both comprise welding the terminal block to the exterior surface of
the housing wall.
24. The method of claim 22 wherein the step of installing at least
one terminal pin assembly in the terminal block includes
threadingly engaging the at least one terminal pin assembly with
the terminal block.
25. The method of claim 24 wherein the step of installing at least
one terminal pin assembly in the terminal block is performed prior
to mounting the terminal block on the housing.
26. The method of claim 24 wherein the step of installing at least
one terminal pin assembly in the terminal block is performed after
mounting the terminal block on the housing.
27. The method of claim 22 wherein the exterior surface of the
housing wall has a cylindrical shape and said method further
includes forming a concave mating surface on the terminal block
wherein the mating surface is flushly engageable with the
cylindrical exterior surface of the housing wall.
28. The method of claim 22 further comprising the step of forming a
groove in the terminal block whereby a cover may be engaged with
the groove to thereby secure the cover to the terminal block.
Description
[0001] The present invention is a continuation-in part of pending
patent application Ser. No. 10/414,332, filed Apr. 15, 2003 in the
name of Zer Kai Yap and entitled "Terminal Block Assembly For A
Hermetic Compressor."
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention pertains to hermetically sealed
compressors and, more particularly, for terminal block assemblies
for such compressors.
[0004] 2. Description of the Related Art
[0005] Various types of compressors are known, including
reciprocating piston, rotary vane and scroll type compressors.
Oftentimes, the compressor assembly will include a hermetically
sealed housing containing a motor and a compression mechanism. The
motor is typically connected to a power source via a terminal
assembly that is mounted in the housing.
[0006] Prior terminal assemblies, generally, include a terminal
body and a plurality of conductor pins. The terminal body is
typically cup-shaped and is mounted within an aperture defined in
the wall of the compressor housing. The terminal body has a
plurality of holes each defined by a collar or annular lip. The
conductor pins extend through and are secured within the holes by
the annular lip and an insulating glass seal, which electrically
insulates the pins from the terminal body. The interior ends of the
conductor pins are connected to lead wires running to the stator,
while the exterior ends of the conductor pins protrude from the
terminal body and are connected to a source of electrical
power.
[0007] A fence is often provided to protect the exterior ends of
the pins protruding from the terminal body. The fence typically
comprises a wall that extends outwardly from the compressor housing
and surrounds the terminal body and protruding pins. One end of the
fence is often attached to, or integrally formed with, the terminal
body. The free end of the fence is usually open and a plug or cap
may fit into, or fasten onto, the free end to close the
opening.
[0008] In order to prevent refrigerant leakage and accommodate the
high pressures within the compressor, parts of the compressor are
machined to extremely close tolerances and the compressor housing
is hermetically sealed. In the case of the terminal assembly, the
terminal body of the assembly is tightly fitted within an aperture
of the compressor housing and is then sealed to the wall of the
housing at the tightly fitting interface of the terminal body and
the sidewalls of the aperture, typically by welding, brazing or the
like. The terminal pins are installed in the holes of the terminal
body and the fence is attached to the terminal body.
[0009] Ideally, terminal assemblies are assembled prior to mounting
and welding the terminal body to the housing. However, the
cup-shaped terminal body of prior terminal assemblies are often
unable to withstand the high heat of welding or brazing.
Consequently, the subsequent welding of the pre-assembled terminal
assembly to the housing often results in damage to the terminal
body, insulators and/or the conductive pins. In addition, the
interior of compressors using carbon dioxide as a working fluid may
reach substantially high temperatures and pressures. Prior terminal
assemblies, particularly the mountings of the conductive pins
within the holes of the terminal body, are often unable to
withstand the high pressures created in carbon dioxide compressors.
Furthermore, the assembly of the fence and plug onto the terminal
body is often complicated and adds additional parts and
manufacturing time. In addition, prior compressors often required
extensive machining of the housing and the housing aperture to
achieve a tight fit between the terminal body and the aperture of
the housing. Such extensive machining adds difficulty, time and
expense to the assembly process.
[0010] Therefore, a need remains for a terminal assembly that is
relatively simple to assemble, can better endure the welding
process by which the terminal assembly is fixed to the compressor
housing, and is better able to withstand the higher pressures and
temperatures experienced in a hermetic compressor using carbon
dioxide as the refrigerant.
SUMMARY OF THE INVENTION
[0011] The present invention provides a hermetic compressor
assembly that includes a terminal body that may be easily mounted
on and hermetically sealed with the compressor housing without
requiring the terminal body and an aperture in the housing to be
manufactured using tight tolerances.
[0012] The present invention comprises, in one form thereof, an
assembly for use with a hermetic compressor that includes a
hermetically sealed housing defining an interior space and
including a housing wall with an interior surface and an exterior
surface. The housing wall defines an aperture extending through the
housing wall and in communication with the interior space. A motor
and a compressor mechanism operably coupled with the motor are
disposed within the interior space. A terminal block is mounted on
the housing wall proximate the aperture and forms a hermetic seal
with the exterior surface of the housing wall. The hermetic seal
encircles the aperture and at least one terminal pin is mounted in
the terminal block and extends through the aperture.
[0013] The terminal block may include a mating surface that is
flushly engaged with the exterior surface of the housing wall and
that encircles the aperture wherein the exterior surface is
cylindrical and the mating surface is a concave surface. The
terminal block may be disposed entirely outwardly of the exterior
surface of the housing wall or include a portion disposed within
the aperture.
[0014] The invention comprises, in another form thereof, a hermetic
compressor assembly that includes a hermetically sealed housing
defining an interior space and including a housing wall having an
interior surface and an exterior surface. The housing wall defines
an aperture in communication with the interior space. A motor, and
a compressor mechanism operably coupled with said motor, are
disposed within said interior space. A terminal block is positioned
over the aperture and is welded to the exterior surface of the
housing at a location spaced radially outwardly of the aperture
with at least one terminal pin being mounted in the terminal block
and extending through the aperture.
[0015] The invention comprises, in yet another form thereof, a
hermetic compressor assembly that includes a hermetically sealed
housing defining an interior space and including a housing wall
with an interior surface and an exterior surface. The housing wall
defines an aperture that extends through the wall and is in
communication with the interior space. A motor and a compressor
mechanism operably coupled with the motor are disposed within the
interior space. A terminal block is mounted on the housing covering
the aperture and forming a hermetic seal with the housing wall. The
terminal block defines an annular groove and at least one terminal
pin extends through the terminal block and has an end projecting
outwardly from the terminal block. The assembly also includes a
cover having a plurality of radially inwardly projecting tabs
engageable with the groove to thereby mount the cover to the
terminal block with the cover substantially enclosing the outwardly
projecting end of the at least one terminal pin.
[0016] The cover may include a plurality of resilient mounting
members extending therefrom with the tabs being disposed on
respective distal ends of the plurality of resilient mounting
members. The terminal block may also include a guide surface
disposed between said annular groove and a distal end of said
terminal block wherein the guide surface tapers radially inwardly
as the guide surface projects from the latching surface to the
distal end. Such a guide surface may have a frustroconical
shape.
[0017] The present invention comprises, in still another form
thereof, a method of assembling a hermetic compressor. The method
includes providing a housing having a housing wall with an interior
surface and an exterior surface, forming an aperture in the housing
wall, and installing at least one terminal pin in a terminal block.
The method also involves mounting the terminal block on the housing
wherein the terminal block covers the aperture and forming a
hermetic seal between the terminal block and the exterior surface
of the housing wall wherein said hermetic seal circumscribes the
aperture.
[0018] The steps of mounting the terminal block to the housing and
forming the hermetic seal between the terminal block and the
exterior surface of the housing wall may both comprise welding the
terminal block to the exterior surface of the housing wall. The
step of installing at least one terminal pin assembly in the
terminal block may include threadingly engaging the terminal pin
assembly with the terminal block and such step may occur either
after or prior to mounting the terminal block on the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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 embodiments of the
invention taken in conjunction with the accompanying drawings,
wherein:
[0020] FIG. 1 is a first sectional view of a hermetic compressor
according to the present invention;
[0021] FIG. 2 is a second sectional view of the hermetic compressor
of FIG. 1;
[0022] FIG. 3 is a top view of the compressor of FIG. 1;
[0023] FIG. 4 is a sectional view of the compressor sub-assembly of
FIG. 1;
[0024] FIG. 5 is a top view of a two-piece separator plate
according to one embodiment of the present invention;
[0025] FIG. 5A is an interior side view of either piece of the
separator plate of FIG. 5;
[0026] FIG. 6 is a top view of a two-piece separator plate
according to another embodiment of the present invention;
[0027] FIG. 6A is an interior side view of a first piece of the
separator plate of FIG. 6;
[0028] FIG. 7 is a top perspective view of a crankcase according to
the present invention;
[0029] FIG. 8 is bottom perspective view of the crankcase of FIG.
7;
[0030] FIG. 9 is a bottom view of the crankcase of FIG. 7;
[0031] FIG. 10 is a sectional view taken along line 10-10 of FIG.
9;
[0032] FIG. 11 is a top view of the crankcase of FIG. 7;
[0033] FIG. 12 is an enlarged view of the encircled region of FIG.
9;
[0034] FIG. 13 is an enlarged, fragmentary sectional view taken
along line 13-13 of FIG. 12;
[0035] FIG. 14 is a perspective view of a terminal block assembly
according to the present invention;
[0036] FIG. 15 is a side view of the terminal block assembly of
FIG. 14;
[0037] FIG. 16 is an exploded view of the terminal block assembly
of FIG. 14 in relation with the housing of a hermetic compressor
according to the present invention;
[0038] FIG. 17 is a front view of the terminal block assembly of
FIG. 14;
[0039] FIG. 18 is an enlarged sectional view of a pin assembly
according to the present invention;
[0040] FIG. 19 is an end view taken along line 19-19 of FIG.
18;
[0041] FIG. 20 is a perspective view of a second embodiment
terminal assembly and protective cover according to the present
invention;
[0042] FIG. 21 is a sectional view of the terminal assembly and
protective cover of FIG. 20;
[0043] FIG. 22 is a top view of the terminal assembly and
protective cover of FIG. 20 installed on a compressor housing
according to the present invention;
[0044] FIG. 23 is a sectional view taken along line 23-23 of FIG.
22;
[0045] FIG. 24 is a plan view of the terminal block of the terminal
assembly FIG. 20;
[0046] FIG. 25 is a sectional view taken along line 25-25 of FIG.
24;
[0047] FIG. 26 is a bottom view of the protective cover of FIG. 22;
and
[0048] FIG. 27 is a sectional view taken along line 27-27 of FIG.
26.
[0049] The embodiments disclosed herein are not intended to be
exhaustive or limit the invention to the precise forms disclosed in
the following description. Rather the embodiments are chosen and
described so that others skilled in the art may utilize its
teachings.
DETAILED DESCRIPTION
[0050] Referring to FIG. 1, hermetic compressor 20 comprises
housing 22 which includes upper housing 24, lower housing 26, and
cylindrical main housing 28. As better illustrated in FIG. 16,
aperture 64 is defined in wall 62 of main housing 28. Returning now
to FIG. 1, housing portions 24, 26 and 28 are formed of sheet steel
having a thickness of between about 0.2 inches (0.508 cm) and 0.4
inches (1.02 cm). Housing portions 24, 26, and 28 are hermetically
sealed by a method such as welding, brazing, or the like.
Alternatively, either upper housing 24 or lower housing 26 may be
integrally-formed with main housing 28. Disposed within housing 22
is motor 30 and compression mechanism 40. Motor 30 includes rotor
36, which is surrounded by stator 32 and fixed to crankshaft 38.
Stator 32 includes windings 34, which are connected by lead wires
(not shown) to a power source (not shown) via terminal assembly 60.
Stator 32 is secured at one end to legs 53 of crankcase or main
bearing 46 and at the opposite end to lower outboard bearing 47.
Discharge muffler 51 is disposed between main bearing 46 and motor
30.
[0051] Compression mechanism 40 includes first cylinder 42 and
second cylinder 44, each having a cylindrical chamber 43 and 45,
respectively. First and second cylinders 42, 44 are separated by
separator plate 50, which has a central bore 57. Chamber 43 of
first cylinder 42 receives gas, which may be, for example, carbon
dioxide or any other suitable refrigerant, at substantially suction
pressure, through intake tube 77. Intermediate pressure muffler 49
is disposed on upper outboard bearing 48 and upper outboard bearing
48 is disposed adjacent first cylinder 42. Upper outboard bearing
48 includes intermediate discharge tube 78, which is in
communication with chamber 43 of first cylinder 42. Intermediate
discharge tube 78 is also in communication with chamber 45 of
second cylinder 44 through intermediate suction tube 79 (FIGS. 2
and 3). Intermediate discharge tube 78 and intermediate suction
tube 79 are in fluid communication with each other externally of
housing 22, and may comprise a common conduit.
[0052] Second cylinder 44 is disposed adjacent to main bearing 46
and chamber 45 is in communication with discharge muffler 51
through valve opening 98 in main bearing 46 (FIGS. 9, 12 and 13).
Referring to FIGS. 9, 12 and 13, valve opening 98 is equipped with
a valve assembly 100 that includes resilient valve 102 sealing
valve opening 98 and valve stop 104. Valve assembly 100 is secured
to main bearing 46 by fastener 106. Referring back to FIGS. 1-3,
discharge tube 81 is in communication with discharge muffler 51.
Crankshaft 38 extends through chamber 45, bore 57, and chamber 43,
and includes two eccentric portions 37, 39 mounted thereon which
are disposed inside chambers 43 and 45, respectively. Roller
bearings 108 provide radial support to eccentric portions 37, 39
and further seal any space between the wall of bore 57 and
crankshaft 38. Crankshaft 38 is radially supported at either end in
lower outboard bearing 47 and upper outboard bearing 48 by needle
roller bearings 110, 112, which prevent deflection of crankshaft
38.
[0053] Turning now to FIGS. 1-3, in operation, compressor 20
receives suction pressure gas into first compression chamber 43
through tube 77, where it is compressed to an intermediate pressure
and discharged into intermediate pressure muffler 49. The
intermediate pressure gas is then discharged externally from
compressor 22 through intermediate discharge tube 78, which extends
from outboard bearing 48 and through housing 22. The intermediate
pressure gas is then introduced into the motor compartment through
intermediate pressure suction tube 79, and is drawn into second
compression chamber 45 and compressed to discharge pressure.
Referring now to FIGS. 1-3 and 13, the discharge pressure gas is
discharged into discharge muffler 51 from second compression
chamber through valve opening 98 in main bearing 46. More
specifically, when pressure reaches a certain pre-determined limit,
the pressure of the discharge pressure gas forces valve 102 to
deflect away from main bearing 46, thereby exposing valve opening
98 to discharge muffler 51. The deflection of valve 102 is limited
by valve stop 104. The discharge gas is then expelled from the
compressor assembly through discharge tube 81, which extends from
main bearing 46 and through housing 22. The displacement volume
ratio of intermediate pressure gas to discharge pressure gas is
approximately 1:10.
[0054] According to one embodiment of the present invention shown
in FIG. 5, separator plate 50 is a two-piece separator plate having
a first piece 52 and a second, complementary piece 54. As
illustrated in FIGS. 5 and 5A, each of first and second pieces 52,
54 includes planar surface 58 having semi-circular central recess
59. First and second pieces 52, 54 may be paired by joining planar
surfaces 58 and fastening first and second pieces using dowel 96,
the ends of which are received within dowel holes 95. When first
and second pieces 52, 54 are paired, semi-circular recesses 59 form
bore 57, which is sized to closely surround crankshaft 38 at a
location between the eccentrics. Two-piece separator plate 50 also
includes bolt clearance holes 56. The two-piece plate design allows
the separator plate 50 to be fitted more closely around the portion
of crankshaft 38 located between eccentrics 37, 39 and sealably
separate compression chambers 43 and 45.
[0055] According to another embodiment of the present invention
shown in FIG. 6, separator plate 250 is a two-piece separator plate
having a first piece 252 and a second, complementary piece 254. As
illustrated in FIGS. 6 and 6A, each of first and second pieces 252,
254 includes annular surface 260 and planar surface 258 having
semi-circular central recess 259. First and second pieces 252, 254
may be paired by joining planar surfaces 258 and fastening first
and second pieces 252, 254 using dowel 296, the ends of which are
received within dowel holes 295. Alternatively, or additionally,
first and second pieces 252, 254 may be secured using fasteners
262, which extend through clearance apertures 266 in second piece
254 and engage threaded apertures 268 defined in interior surface
258 of first piece 252. Notches 264 may be defined in annular
surface 260 of second piece 254 for receiving fasteners 262 and for
housing the head of fasteners 262 within the diametric perimeter of
annular surface 260. Two-piece separator plate 250 also includes
bolt clearance holes 256.
[0056] In assembling compressor 20 according to the present
invention, main bearing 46 is placed on a holding device with the
upper side 33 facing up. Second cylinder 44 is then placed on the
upper side 33 of main bearing 46 and crankshaft 38 is inserted into
main bearing 46 and second cylinder 44. Roller bearing 108 is
mounted on crankshaft 38 within chamber 45. First and second pieces
52, 54 of separator plate 50 are then positioned on top of second
cylinder 44 and paired such that semi-circular central recesses 59
closely capture the portion of crankshaft 38 located between
eccentrics 37, 39. First and second pieces 52, 54 are connected to
one another using dowels 96, the ends of which are inserted into
holes 95 (FIG. 5). Alternatively, first and second pieces 252, 254
of separator plate 250 may be positioned on top of second cylinder
44 and paired such that semi-circular central recesses 259 closely
capture the portion of crankshaft 38 located between eccentrics 37,
39. First and second pieces 252, 254 may then be connected to one
another using dowels 296 and/or fasteners 262. Roller bearing 108
is mounted on crankshaft 38 and first cylinder 42 is then
positioned on separator plate 50 such that roller bearing is
disposed within chamber 43.
[0057] Outboard bearing 48 and intermediate discharge muffler 49
are then positioned atop first cylinder 42 and five bolts
(represented by dashed lines 154 in FIG. 1) are placed through
clearance holes in intermediate discharge muffler 49, outboard
bearing 48, first cylinder 42, two-piece separator plate 50, and
second cylinder 44, and engage threaded holes 41 (FIG. 7) in the
upper side 33 of main bearing 46. Next, main bearing 46 is removed
from the holding device and annular discharge muffler 51 is
positioned on the underside 35 of main bearing 46 between legs 53.
Five bolts are then inserted through clearance holes in discharge
muffler 51 and engage one end of threaded holes 41 at the underside
35 of main bearing 46 (FIG. 8) to secure discharge muffler 51 to
main bearing 46. Alternatively, the five bolts 154 extending
through intermediate discharge muffler 49, outboard bearing 48,
first cylinder 42, two-piece separator plate 50, second cylinder
44, and holes 41 can be lengthened to further extend completely
through holes 41 and discharge muffler 51 and can be secured with
nuts.
[0058] Crankshaft 38 is then affixed to rotor 36 by heat-shrinking.
Stator 32 is then placed over rotor 36, and outboard bearing 47 is
positioned over the end of stator 32 and rotor 36. Four threaded
bolts or like fasteners (not shown) are inserted into clearance
holes (not shown) provided in outboard bearing 47 and stator 32.
Bolts are then threaded into four threaded holes 158 provided in
the ends of legs 53 of main bearing 46 (FIG. 8).
[0059] The resulting compressor sub-assembly 21, shown in FIG. 4,
is then installed in housing 22 by, first, heat-expanding main
housing 28, and inserting compressor sub-assembly 21 into
main-housing 28 (FIG. 1). Main housing 28 is then allowed to cool
thereby shrink-fitting housing 28 onto sub-assembly 21, such that
sub-assembly 21 is in contact with the housing at the peripheries
of main bearing 46 and outboard bearing 47. The upper and lower
housing portions are then welded to the main housing portion 28 to
hermetically seal compressor 20. Tubes 77, 78, 79, and 81 are then
inserted into openings (not shown) in housing 28 such that the
inner portion of tubes 77, 78, 79 and 81 extend into openings (not
shown) in first cylinder 42, outboard bearing 48, outboard bearing
47 and main bearing 46, respectively. The openings in first
cylinder 42, outboard bearing 48, outboard bearing 47 and main
bearing 46 are provided with a seal, such as an o-ring, to
sealingly receive tubes 77, 78, 79 and 81. The outer portion of
tubes 77, 78, 79 and 81 are then sealed to housing 38 by welding,
brazing or the like.
[0060] With reference to FIGS. 14-19, according to one embodiment
of the present invention, terminal assembly 60 generally includes
machined metallic disk 66 and three pin assemblies 80. Disk 66
includes three equally spaced-apart, threaded holes extending
therethrough. Referring particularly to FIGS. 15 and 16, interior
side 68 of disk 66 defines a first diameter portion 76 having
diameter D.sub.1 sized to snugly fit within aperture 64 in wall 62
of housing 22. Disk 66 also includes a second diameter portion 74
adjacent first diameter portion 76 and having diameter D.sub.2,
which is larger in diameter than both D.sub.1 and aperture 64. As
shown in FIGS. 3 and 16, first diameter portion 76 of disk 66 fits
into aperture 64. Second diameter portion 74 abuts wall 62, thereby
restricting further movement of disk 66 into aperture 64 and
providing a sealing region 71 between the surface of second
diameter portion 74 and housing wall 62. Disk 66 is hermetically
sealed to the exterior surface of housing wall 62 at sealing region
71 located at the radially outer edge of larger diameter portion 74
of disk 66 by welding, brazing or other means that fully encircles
aperture 64.
[0061] Turning now to FIGS. 18 and 19, each pin assembly 80
includes an elongate conductive pin 82, electrical insulator 88
disposed about pin 82, annular collar 84 disposed about a portion
of electrical insulator 88, and tabs 90 positioned at both the
interior end 92 and exterior end 94 of pin 82. Electrical insulator
88 includes Teflon.RTM. sleeve 114 extending along a length of pin
82 at interior end 92, sintered glass portions 116, and a fused
glass portion 118. Between fused glass portion 118 and one of the
sintered glass portions 116 is freon-proof epoxy resin 120, and
parts of both fused glass portion 118 and sintered glass portion
116 are disposed between pin 81 and annular collar 84. Annular
collar 84 includes hexagonal head portion 85 and shaft portion 87,
which includes threaded outer surface 86. Each pin assembly 80 is
received in a corresponding one of threaded holes 72 in disk 66 and
is secured in hole 72 via a threaded engagement between threaded
collar surface 86 and threaded surface of hole 72. In this threaded
engagement, pin assemblies 80 are more securely fixed in holes 72,
and therefore, are capable of withstanding the high pressures
created in carbon dioxide compressors.
[0062] As is typical in the art, the interior end 92 of pin 82 may
be connected to lead wires (not shown) extending from stator
windings 34 via a connector clip, cluster block or other electrical
connecting means. The exterior end 94 of pin 82 is appropriately
connected to a power source (not shown) to provide power to pin 82
and, ultimately, to stator 32.
[0063] Disk 66 is a metal casting, such as steel, that is capable
of enduring the heat of welding and/or brazing, and is machined to
final shape. Disk 66 is of substantial thickness, the overall
thickness of disk 66 as measured between exterior side 70 and
interior side 68 is, preferably, about one inch. However, thickness
can vary, provided that disk 66 is thick enough to endure the heat
of hermetic sealing and the pressures of carbon dioxide compression
without damage or deformity to disk 66 or pin assemblies 80. Second
diameter portion 74, particularly, should be of substantial
thickness, preferably, about 0.300 inches. First diameter portion
76 should have sufficient thickness to securely fit into aperture
64, preferably, about 0.200 inches.
[0064] This terminal assembly withstands the heat of welding and
the pressures created in a carbon dioxide compressor, and
therefore, provides a more robust compressor assembly design. In
one embodiment of the present invention, the terminal assembly is
assembled by, first, mounting metallic disk 66 on housing 22 by
inserting first diameter portion 76 into aperture 64 until second
larger diameter portion 74 of metallic disk 66 engages outer wall
62 of housing 22. Then second diameter portion 74 is hermetically
sealed to housing outer wall 62 by welding, brazing or the like
around the perimeter of second diameter portion 74. Finally,
terminal pin assemblies 80 are inserted into holes 72 and annular
collars 84 are secured to hole 72 in a threaded engagement.
[0065] Alternatively, the terminal assembly can be assembled prior
to welding disk 66 to wall 62 of housing 22. In this case, terminal
assembly 60 is assembled by, first, installing terminal pin
assemblies 80 within holes 72, as described above. With the pin
assemblies 80 threadedly secured in holes 72, metallic disk 66 is
mounted in aperture 64 and second diameter portion 74 is
hermetically sealed to outer wall 62 without causing damage to disk
66 or pin assemblies 80.
[0066] According to another embodiment of the present invention
exemplified in FIGS. 20-27, terminal block 160 is a solid, metallic
cylindrical block having mating end 163 and distal or projecting
end 165. As can be seen in FIGS. 21 and 24, terminal block 160 also
includes three equally-spaced, tapped and threaded holes 172
extending through terminal block 160 from mating end 163 to
projecting end 165. Holes 172 receive terminal pin assemblies 180
in a threaded-engagement as described above with respect to pin
assemblies 80. Terminal block 160 is a metal casting, e.g., steel,
that is capable of enduring the heat of welding and brazing, and is
machined to form the final shape. Terminal block 160 is of
substantial thickness, the overall thickness of terminal block 160
as measured along the axis between mating end 163 and projecting
end 165 is, preferably, between about 0.5 inches (1.27 cm) to about
1 inch (2.54 cm). However, the thickness can vary, provided that
terminal block 160 is thick enough to endure the heat of hermetic
sealing and the pressures of carbon dioxide compression without
damage or deformity to terminal block 160 or pin assemblies
180.
[0067] Referring now to FIGS. 22, 23 and 25, mating end 163 has a
concave mating surface 164 having a radius of curvature that
corresponds to the curvature of exterior surface 161 of housing
wall 162, such that mating surface 164 of terminal block 160 lies
flush against housing wall 162. Housing wall 162 may be
substantially identical to housing wall 62 described above and has
an exterior surface 161 facing outwardly and an interior surface
159 that faces the hermetically sealed interior space 193 defined
by the housing and containing the motor/compressor subassembly 21.
Although FIGS. 20-27 show the housing wall as having a
substantially cylindrical shape, it should be understood that
housing wall 162 may have alternative shapes. Accordingly, mating
surface 164 can take other shapes to engage such alternatively
shaped housings. Furthermore, the entirety of mating surface 164
need not be shaped to conform to the housing. Instead, mating
surface 164 may be formed such that only an outer perimeter portion
of mating surface 164 is shaped to conform to the housing and
contacts exterior surface 161 of housing wall 162 to sealingly
encircle aperture 164.
[0068] Terminal block 160 is mounted on the exterior surface of
housing wall 162 such that terminal block 160 is disposed entirely
outside of exterior surface 161 of housing wall 162, as shown in
FIG. 23. Terminal block 160 is hermetically sealed to exterior
surface 161 of housing wall 162 by welding, brazing or the like
around the perimeter of mating end 163. Because the hermetic seal
between terminal block 160 and housing wall 162 is spaced radially
outwardly of aperture 164 and not formed with the sidewalls of
aperture 164, terminal block 160 and aperture 164 do not have to
form a tight fit and, when manufacturing the housing, aperture 164
may be located and formed using relatively loose tolerances.
[0069] As illustrated in FIG. 25, terminal block 160 may also
include annular groove 166, which is defined in perimetrical
surface 167 of terminal block 160 and extends about the perimeter
or circumference of terminal block 160. Perimetrical surface 167
may include frustoconical guide surface 168 adjacent groove 166.
Guide surface 168 tapers inwardly moving from groove 166 to
projecting end 165. In other words, guide surface 168 slopes from a
first diameter D.sub.3 at projecting end 165 to a larger second
diameter D.sub.4 adjacent groove 166. Both annular groove 166 and
tapered guide surface 164 cooperate to receive a snap-fit
protective cover, such as cover 190 illustrated in FIGS. 20, 21, 26
and 27.
[0070] Cylindrical cover 190 may be formed of a plastic such as
polyurethane or other suitable material, and includes six, equally
spaced-apart, resilient mounting members or legs 192. Each leg 192
includes a radially inwardly projecting tab or lip 194 that is
shaped and sized to fit within annular groove 166. To install cover
190 on terminal block 160, resilient legs 192 are urged along
tapered guide surface 164, causing resilient legs 192 to flex
outward. When lip 194 reaches groove 164, resilient legs 192 spring
inwards, snapping lip 194 into groove 164, thereby locking cover
190 onto terminal block 160. The more distal edge surface of groove
166 forms latching surface 195 that engages lips 194 and prevents
cover 190 from being removed from the terminal body without prying
lips 194 radially outwardly to disengage lips 194 from groove
166.
[0071] When attached, cover 190 encloses the outwardly projecting
ends 181 of the terminal pins. Cover 190 also includes a D-shaped
hole 196 through which a wire assembly leading from the power
source can extend. Cover 190 protects the terminal assembly from
damage during operation and is relatively easy to install. Although
cover 190 and terminal block 160 illustrated in FIGS. 20-27 both
have a circular cross section where they are engaged, it should be
understood that terminal block 160 and cover 190 can be any
suitable shape, such as a generally rectangular shape.
[0072] Similar to metallic disk 66 shown in FIGS. 14-19, terminal
block 160 shown in FIGS. 20-25 withstands both the heat of welding
and the pressures created in a carbon dioxide compressor.
Consequently, terminal block 160 provides a robust compressor
assembly design. In the illustrated embodiments, pin assemblies 180
are mounted in holes 172 prior to mounting of the terminal block to
housing wall 162, however, if desired, it would also be possible to
mount pin assemblies 180 in holes 172 after securing terminal block
160 on housing wall 162.
[0073] While this invention has been described as having an
exemplary design, the present invention may be further modified
within the scope of this disclosure. This application is therefore
intended to cover any variations, uses, or adaptations of the
invention using its general principles. 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.
* * * * *