U.S. patent application number 09/973245 was filed with the patent office on 2002-01-31 for scroll compressor with axially floating non-orbiting scroll and no separator plate.
Invention is credited to Barito, Thomas, Bush, James W., Hahn, Greg, Hill, Joe T., Hugenroth, Jason, Sun, Zili, Williams, John R., Zamudio, Carlos.
Application Number | 20020012596 09/973245 |
Document ID | / |
Family ID | 24385994 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020012596 |
Kind Code |
A1 |
Bush, James W. ; et
al. |
January 31, 2002 |
Scroll compressor with axially floating non-orbiting scroll and no
separator plate
Abstract
An improved scroll compressor having an axially movable
non-orbiting scroll eliminates the need for a separator plate. With
the elimination of the separator plate, a back pressure chamber is
provided to resist the discharge pressure which will be directed
against a rear face of the non-orbiting scroll. In other
embodiments, a seal on the rear of the non-orbiting scroll contacts
the inner periphery of the end cap. Various ways of increasing the
discharge pressure volume, or eliminating undesirable noise are
also disclosed. Further, several ways of connecting the end cap to
the center shell are also disclosed.
Inventors: |
Bush, James W.;
(Skaneateles, NY) ; Sun, Zili; (Arkadelphia,
AR) ; Zamudio, Carlos; (Arkadelphia, AR) ;
Hugenroth, Jason; (Hope, AR) ; Hahn, Greg;
(Arkadelphia, AR) ; Barito, Thomas; (Arkadelphia,
AR) ; Hill, Joe T.; (Bristol, VA) ; Williams,
John R.; (Bristol, VA) |
Correspondence
Address: |
Anthony P. Cho
CARLSON, GASKEY & OLDS, P.C.
Suite 350
400 West Maple Road
Birmingham
MI
48009
US
|
Family ID: |
24385994 |
Appl. No.: |
09/973245 |
Filed: |
October 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09973245 |
Oct 8, 2001 |
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09596104 |
Jun 16, 2000 |
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6309197 |
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Current U.S.
Class: |
418/55.5 ;
418/181; 418/57 |
Current CPC
Class: |
F04C 18/0215 20130101;
F04C 27/005 20130101; F04C 2240/603 20130101; F04C 2230/231
20130101; F01C 21/10 20130101; F04C 23/008 20130101 |
Class at
Publication: |
418/55.5 ;
418/57; 418/181 |
International
Class: |
F04C 018/04; F04C
029/06 |
Claims
1. A scroll compressor comprising: a first scroll having a base and
a generally spiral wrap extending from said base; a second scroll
having a base and a generally spiral wrap extending from said base;
a shaft for causing said second scroll to orbit relative to said
first scroll, said first scroll being operable to move axially
along a rotational axis of said shaft relative to said second
scroll; and said first and second scrolls and said shaft being
mounted within a sealed housing, said sealed housing including a
center shell and an end cap enclosing said center shell, a
refrigerant trapped between said wraps of said first and second
scrolls being compressed and delivered through a discharge port
extending through said base of said first scroll into a discharge
pressure chamber, said discharge pressure chamber being defined
between a face of said base of said first scroll and said end
cap.
2. A scroll compressor as recited in claim 1, wherein said first
scroll member has a seal at an outer periphery of its base which
seals an inner periphery of said end cap.
3. A scroll compressor as recited in claim 1, wherein a refrigerant
at a compressed location between said wraps is tapped to a back
pressure chamber on an opposed side of said first scroll from said
discharge chamber, said tapped refrigerant acting in opposition to
a force from said discharge pressure chamber.
4. A scroll compressor as recited in claim 3, wherein a tap extends
through said second scroll to deliver a refrigerant into a chamber
in a crankcase supporting said second scroll, said chamber
communicating with a back pressure chamber applying a force to a
face of said first scroll opposed an outer face which sees said
discharge pressure chamber.
5. A scroll compressor as recited in claim 4, wherein a pair of
seals define said chamber.
6. A scroll compressor as recited in claim 1, wherein a seal is
formed between a face of said first scroll which contacts an end
face of said end cap.
7. A scroll compressor as recited in claim 6, wherein said seal
defines a discharge pressure chamber radially inwardly of said
seal, and a suction pressure chamber radially outwardly of said
seal.
8. A scroll compressor as recited in claim 7, wherein a separate
seal is positioned between said end cap and said first scroll to
seal between said suction and discharge pressure chambers.
9. A scroll compressor as recited in claim 7, wherein a metal to
metal contact between a sealing portion on said base of said first
scroll and said surface of said end cap provides said seal.
10. A scroll compressor as recited in claim 7, wherein a domed area
of said end cap extends axially outwardly away from said base of
said first scroll to define an enlarged discharge pressure
chamber.
11. A scroll compressor as recited in claim 1, wherein said center
shell is connected to said end cap with said end cap having a
portion fitting radially inwardly of a portion of said center
shell.
12. A scroll compressor as recited in claim 11, wherein said end
cap further having a portion facing a portion of said center shell,
and said portion which is radially inwardly of a portion of said
center shell being positioned radially inwardly of said facing
portion.
13. A scroll compressor as recited in claim 11, wherein said end
cap having a step portion with a facing portion facing a portion of
said center shell, and a second portion positioned radially
inwardly of said facing portion, said center shell having a facing
portion facing said second portion of said end cap.
14. A scroll compressor as recited in claim 1, wherein a portion of
said end cap is domed outwardly away from said base of said first
scroll to increase the volume of said discharge pressure
chamber.
15. A scroll compressor as recited in claim 1, wherein a portion of
said base of said first scroll is cut away to increase a discharge
chamber volume.
16. A scroll compressor as recited in claim 1, wherein a torturous
path is positioned on said discharge port such that gas leaving
said discharge port must move through a torturous path.
17. A scroll compressor as recited in claim 1, wherein a Helmholtz
resonator is positioned on a discharge pressure flow line.
18. A scroll compressor as recited in claim 1, wherein a muffler is
positioned on a discharge port outside said sealed housing.
19. A scroll compressor as recited in claim 1, wherein said
discharge chamber further being defined by a seal between said
first scroll and one of said center shell and said end cap.
20. A scroll compressor as recited in claim 1, wherein a
cross-sectional area of said discharge pressure chamber projected
onto a rear of said base of said first scroll is relatively
equivalent to the cross-sectional area of a plane defined normal to
said rotational axis, and projected onto said end cap.
21. A scroll compressor comprising: a first scroll having a base
and a generally spiral wrap extending from said base; a second
scroll having a base and a generally spiral wrap extending from
said base; a shaft for causing said second scroll to orbit relative
to said first scroll, said first scroll being operable to move
axially along a rotational axis of said shaft relative to said
second scroll; and said first and second scrolls and said shaft
being mounted within a sealed housing, said sealed housing
including a center shell and an end cap enclosing said center
shell, a refrigerant trapped between said wraps of said first and
second scrolls being compressed and delivered through a discharge
port extending through said base of said first scroll into a
discharge pressure chamber, said discharge pressure chamber being
defined between a face of said base of said first scroll and said
end cap, refrigerant at a compressed location between said wraps
being tapped to a back pressure chamber on an opposed side of said
first scroll from said discharge pressure chamber, said tapped
refrigerant acting in opposition to a force from said discharge
pressure chamber, and a seal between an end face of said first
scroll and an end face of said end cap.
22. A scroll compressor as recited in claim 21, wherein said seal
defines said discharge pressure chamber axially inwardly of said
seal and a suction pressure chamber radially outwardly of said
seal.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a scroll compressor wherein the
non-orbiting scroll is of the type that moves axially for a limited
distance. In the inventive embodiments, a separator plate which has
typically been placed between the base of the non-orbiting scroll
and an outer end cap is eliminated.
[0002] Scroll compressors are becoming widely utilized in
refrigerant compression applications. In a standard scroll
compressor, a first scroll has a base and a generally spiral wrap
extending from the base. A second scroll has a base and a generally
spiral wrap interfitting with the base of the first scroll. A
second scroll is driven to orbit relative to the first scroll.
Typically, one of the first and second scrolls must move axially to
be held in engagement with the other scroll. A refrigerant is
entrapped between the wraps of the two scrolls and compressed as
the second scroll orbits relative to the first. The entrapped
refrigerant creates a force tending to move the two scrolls away
from each other. Thus, a portion of the compressed fluid is tapped
behind the base of one of the two scrolls to resist this so-called
separating force. In one common type of scroll compressor, the
first scroll receives the tapped compressed fluid, and is allowed
to move for a limited axial distance.
[0003] Typically, scroll compressors are enclosed in a sealed
compressor housing. In such sealed compressor housings, a center
shell receives an end cap which defines a fluid tight chamber. A
separator plate defines a discharge pressure chamber. A separator
plate defines a discharge pressure chamber on one side and a
suction pressure chamber on the other side. Suction pressure fluid
is allowed to enter the compressor housing through the center
shell, and communicate with an area around a motor, cooling the
motor. The separator plate performs the function of separating the
interior of the housing into the discharge and suction pressure
chambers.
[0004] It would be desirable to simplify the number of components
in the above discussed scroll compressor.
SUMMARY OF THE INVENTION
[0005] In a disclosed embodiment of this invention, an axially
movable non-orbiting scroll in a scroll compressor also separates
the interior of the housing into the suction and discharge pressure
chambers. In this way, the requirement of a separate separator
plate is eliminated.
[0006] With the elimination of the separate separator plate, the
base of the non-orbiting scroll includes a sealing member which
seals with an inner surface of an end cap. In one embodiment, the
seal defines the suction chamber outwardly of the seal, and a
discharge chamber inwardly of the seal. With such an arrangement,
the volume of the discharge pressure chamber is reduced compared to
the prior art. This might result in increased discharge pressure
pulsation. Thus, several modifications are utilized to increase the
volume. In one, the end cap is domed outwardly to increase the
volume of the discharge pressure chamber radially inwardly of the
seal. In other embodiments, while the volume may not be increased,
the pressure pulsations from the discharge chamber are reduced
through any one of several features. As one example, a torturous
path may be provided for the discharge pressure flow. In another
embodiment, the base of the discharge pressure chamber may be cut
away to increase the volume. In yet another embodiment, a Helmholtz
resonator is utilized to lower the magnitude of the discharge
pressure pulsation. In other embodiments, a discharge muffler may
be mounted outwardly of the housing, thus lowering the necessary
volume inside the housing.
[0007] In another embodiment of this invention, at least a large
portion of the base of the non-orbiting scroll sees the discharge
pressure itself on an opposed face from the compression chambers,
the separating force is actually no longer merely overcoming the
force of the refrigerant. Instead, the discharge pressure applies a
force to the non-orbiting scroll member towards the orbiting scroll
members at a level exceeding the separating force. Thus, a back
pressure chamber is utilized to resist this excess discharge
pressure. In a preferred embodiment a portion of the compressed
refrigerant is tapped to a chamber defined by a pair of seals
within a crankcase. This back pressure chamber resists the force
from the discharge pressure chamber, and is combined with the
separating force to maintain the orbiting and non-orbiting scroll
members in proper position relative to each other.
[0008] In other features of this invention, various methods and
arrangements for connecting the end cap to the center shell are
disclosed. In the past, the separating plate has typically been
incorporated into this connection. With the elimination of the
separator plate, other structures must be utilized.
[0009] These and other features of the present invention can be
best understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross-sectional view of an inventive first
embodiment of a scroll compressor.
[0011] FIG. 2A is a cross-sectional view through another embodiment
of the present invention.
[0012] FIG. 2B shows a further feature which may modify the FIG. 2a
embodiment.
[0013] FIG. 2C shows yet another embodiment.
[0014] FIG. 2D shows yet another embodiment which may modify the
FIG. 2A embodiment.
[0015] FIG. 2E shows yet another embodiment.
[0016] FIG. 2F shows yet another embodiment.
[0017] FIG. 3A shows a first housing connection.
[0018] FIG. 3B shows a second housing connection;
[0019] FIG. 3C shows a third housing connection.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0020] A scroll compressor 20 is illustrated in FIG. 1 having an
end cap 22 welded to a center shell 24. A discharge tube 26 extends
outwardly of the end cap 22. A non-orbiting scroll 28 is received
within the end cap 22, and is of the type which may move through a
limited axial distance. Non-orbiting scroll 28 has a wrap 30, and a
discharge port 32 leading to a discharge pressure chamber 34. An
orbiting scroll 36 has a wrap 38 which interfits with the wrap 30
to define compression chambers. A crankcase 52 mounts scroll 36. A
shaft 39 drives the orbiting scroll 36, as known. As shown, with
this invention, there is no separator plate separating discharge
pressure chamber 34 from the rear of the base of the non-orbiting
scroll 28. Thus, the pressure in the discharge pressure chamber 34
acts on the rear face of the non-orbiting scroll base 28. The
present invention taps compressed fluid to resist this force.
[0021] As shown, a tap 40 leads to a chamber 42 which may be
generally cylindrical. Chamber 42 leads to a tap 44, which in turn
leads to a back pressure chamber 46. Back pressure chamber 46 is
defined by seals 48 and 50. The tapped pressurized refrigerant in
chamber 46, in addition to the separating force from the
refrigerant trapped in the compression chambers, resist the force
from the discharge chamber 34 tending to force the two scroll
members together to an undesirable amount. The size and position of
the taps leading to the chamber 46 are designed to achieve a proper
balance between the forces in the chamber 34 acting on the rear of
the non-orbiting scroll 28 and the combined forces acting in
opposition to that force.
[0022] A seal 29 seals the outer periphery of the non-orbiting
scroll 28 in this embodiment. Thus, a chamber 35 on one side of
seal 29 is at suction pressure, while the pressure chamber 34 on
the opposed side of seal 29 is at discharge pressure. This
embodiment reduces the number of components and simplifies the
assembly of the scroll compressor.
[0023] FIG. 2A shows another embodiment wherein a dome portion 53
of the end cap 22 is positioned inwardly of seal structures 56 on
the base of the non-orbiting scroll 28. A seal member 58 is
positioned between seal portions 56. The seal portions are shown
somewhat schematically. Any appropriate seal may be utilized. As
the non-orbiting scroll 28 is moved within the chamber, the seal 58
ensures that the chamber 59 inwardly of the seal remains at
discharge pressure due to its communication with the discharge port
32 while the chamber 55 outwardly of the seal 58 is at suction
pressure. A discharge port 54 communicates with the volume 59. With
this embodiment, due to the dome, the seal can still easily define
the discharge and suction sides of the compressor, while still
providing a relatively large volume of discharge gas.
[0024] A tap 200 will tap an intermediate pressure refrigerant to a
back pressure chamber defined by the seals 56 and 58. This
structure may be basically as known, and is shown schematically in
FIG. 2A. This type back pressure chamber is the more typical way of
addressing the separating force between the two scroll members, and
may actually be preferred over the arrangement of FIG. 1.
[0025] FIG. 2B shows another embodiment wherein the seal surface is
provided by a metal to metal contact between a seal member 60 on
the non-orbiting scroll and the end cap 22.
[0026] FIG. 2C shows another way of attending to undesirable noise
due to the reduced volume of the discharge pressure chamber. In
this embodiment, the discharge port 70 extending through the
non-orbiting scroll 71 base leads to a labyrinth flow 72 having
facing structure 73 and 75. Thus, the refrigerant must flow through
a torturous path, reducing noise in the refrigerant flow.
[0027] FIG. 2D shows another embodiment 74 having sealing structure
76 similar to the FIG. 2A seal. An area inwardly of the sealing
structure 76 is cut away such as shown at 78. The discharge port 80
extends into the cutaway area 78. In this way, the volume of the
discharge pressure chamber 79 is increased compared to an
embodiment where the cutaway portion 78 does not exist. Stated
another way, the non-orbiting scroll member 74 has the cutaway
portion 78 formed to be closer to the orbiting scroll than portions
82 outwardly of the sealing portion 76.
[0028] FIG. 2E shows an embodiment 84 having its discharge port 86
leading to a Helmholtz resonator 88. The Helmholtz resonator is
connected through a tap 90 to the discharge port 86. As is known,
the Helmholtz resonator can be tuned to eliminate specific noises
which are to be experienced in the particular compressor at
discharge due to the reduced volume of the discharge chamber.
[0029] FIG. 2F shows yet another embodiment 91. In embodiment 91,
the end cap 96 communicates with a discharge tube 92 which leads to
a muffler 94. The muffler 94 is thus positioned outwardly of the
sealed housing. In this way, the muffling of the noise occurs
outwardly of the housing and the reduced size of the discharge
chamber is addressed.
[0030] In the prior art, the separator plate was also typically
part of the structure between the several housing members. Thus,
alternative ways of connecting the end cap to the center shell must
be developed due to the elimination of the separator plate.
[0031] As shown in FIG. 3A, an embodiment 100 includes a center
shell 102 having an end cap 104 which extends inwardly of the
center shell 102 and receives a weld joint 106.
[0032] FIG. 3B shows an embodiment 108 wherein the end cap 110 is
mounted on the center shell 112 and receives a weld joint 114. The
end cap 110 has a finger 116 extending downwardly at a position
radially inwardly of the center shell, and another portion 117
facing an upper portion of the center shell 112.
[0033] FIG. 3C shows an embodiment 120 wherein the end cap 122 has
finger 124 and an end portion 125 facing a center shell 126 having
portions 128 and 129. Again, a weld joint 130 secures the two.
[0034] In general, the discharge pressure chamber could be
described as being defined between a base of the non-orbiting
scroll and the end cap of the housing, along with being also
defined by a sealing element between the non-orbiting scroll and
either the end cap or the center shell. Further, the discharge
pressure chamber could be defined by a cross-sectional area on the
rear of the base of the non-orbiting scroll which is relatively
close in size to the cross-sectional area of a plane normal to an
axis of rotation of the shaft 39, over which the discharge pressure
chamber is defined on the end cap.
[0035] The present invention thus defines scroll compressors
wherein the non-orbiting scroll is axially movable, and wherein the
separator plate is eliminated. A worker of ordinary skill in this
art would recognize that many modifications would come within the
scope of this invention. Thus, the following claims should be
studied to determine the true scope and content of this
invention.
* * * * *