U.S. patent application number 13/949327 was filed with the patent office on 2014-09-18 for scroll compressor with a bypass.
The applicant listed for this patent is Honggyun JIN, Suchul KIM, Kiwon PARK, Juhwan YUN. Invention is credited to Honggyun JIN, Suchul KIM, Kiwon PARK, Juhwan YUN.
Application Number | 20140271302 13/949327 |
Document ID | / |
Family ID | 50241278 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140271302 |
Kind Code |
A1 |
KIM; Suchul ; et
al. |
September 18, 2014 |
SCROLL COMPRESSOR WITH A BYPASS
Abstract
An upper back pressure type scroll compressor having a bypass is
provided. The scroll compressor may include a casing, a discharge
cover, a main frame, a first scroll supported by the main frame,
and a second scroll that forms a suction chamber, an intermediate
pressure chamber, and a discharge chamber together with the first
scroll. The second scroll may include a bypass hole that
communicates with the intermediate pressure chamber. The scroll
compressor may also include a back pressure chamber assembly
coupled to an upper portion of the second scroll by a fastening
device and a bypass valve to open and close the bypass hole. The
back pressure chamber assembly may include a discharge path by
which the discharge chamber and the discharge space may communicate
with each other and a bypass valve to open and close the bypass
hole.
Inventors: |
KIM; Suchul; (Seoul, KR)
; JIN; Honggyun; (Seoul, KR) ; PARK; Kiwon;
(Seoul, KR) ; YUN; Juhwan; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KIM; Suchul
JIN; Honggyun
PARK; Kiwon
YUN; Juhwan |
Seoul
Seoul
Seoul
Seoul |
|
KR
KR
KR
KR |
|
|
Family ID: |
50241278 |
Appl. No.: |
13/949327 |
Filed: |
July 24, 2013 |
Current U.S.
Class: |
418/55.1 |
Current CPC
Class: |
F04C 18/0215 20130101;
F04C 23/008 20130101; F04C 18/023 20130101; F04C 18/0261 20130101;
F04C 27/005 20130101; F04C 28/26 20130101 |
Class at
Publication: |
418/55.1 |
International
Class: |
F04C 18/04 20060101
F04C018/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2013 |
KR |
10-2013-0028775 |
Mar 18, 2013 |
KR |
10-2013-0028783 |
Mar 18, 2013 |
KR |
10-2013-0028791 |
Claims
1. A scroll compressor, comprising: a casing; a discharge cover,
the discharge cover dividing an inner space of the casing into a
suction space and a discharge space; a main frame, the main frame
being spaced apart from the discharge cover; a first scroll
supported by the main frame, the first scroll performing an orbital
motion with respect to a rotational shaft thereof in operation; a
second scroll that forms a suction chamber, an intermediate
pressure chamber, and a discharge chamber together with the first
scroll, the second scroll being movable with respect to the first
scroll and comprising a bypass hole that communicates with the
intermediate pressure chamber; a back pressure chamber assembly
coupled to the second scroll, the back pressure chamber assembly
comprising a back pressure plate and a floating plate and being
configured to press the second scroll toward the first scroll, the
back pressure chamber assembly further having a discharge path by
which the discharge chamber and the discharge space with
communicate with each other; and a bypass valve that opens and
closes the bypass hole, wherein a bypass path by which the bypass
hole and the discharge path communicate with each other is formed
between facing surfaces of the back pressure chamber assembly and
the second scroll.
2. The scroll compressor of claim 1, wherein the back pressure
plate includes a groove formed therein and the floating plate is
movably disposed in the groove.
3. The scroll compressor of claim 2, wherein a lower surface of the
back pressure plate faces an upper surface of the second
scroll.
4. The scroll compressor of claim 3, wherein the bypass path is
formed between the lower surface of the back pressure plate and the
upper surface of the second scroll and extends in a lateral
direction.
5. The scroll compressor of claim 1, wherein the bypass path
includes a groove formed in one of the lower surface of the back
pressure plate or the upper surface of the second scroll.
6. The scroll compressor of claim 1, wherein the bypass valve is
opened and closed by a pressure difference between the intermediate
pressure chamber and the discharge space.
7. The scroll compressor of claim 1, further comprising a
restrictor that restricts an open degree of the bypass valve.
8. The scroll compressor of claim 7, wherein the restrictor is
formed on a lower surface of the back pressure chamber
assembly.
9. The scroll compressor of claim 7, wherein the restrictor
comprises a retainer disposed on a lower surface of the back
pressure chamber assembly.
10. The scroll compressor of claim 1, wherein the bypass path is
defined by a groove concaved from a lower surface of the back
pressure chamber assembly, and an upper surface of the second
scroll, and wherein the bypass valve is configured to open and
close the bypass hole via a movement within the groove.
11. The scroll compressor of claim 10, wherein the movement of the
bypass valve is restricted by an inner surface of the groove.
12. The scroll compressor of claim 1, wherein the bypass path is
defined by a groove concaved from an upper surface of the second
scroll and a lower surface of the back pressure chamber assembly,
and wherein the bypass valve is configured to open and close the
bypass hole via a movement within the groove.
13. The scroll compressor of claim 12, wherein the movement of the
bypass valve is restricted by an inner surface of the groove.
14. The scroll compressor of claim 1, wherein the bypass valve
comprises: a valve body configured to cover the bypass hole; and a
valve support configured to fix the valve body between the second
scroll and the back pressure chamber assembly.
15. The scroll compressor of claim 14, wherein the valve body
comprises a plurality of valve bodies.
16. The scroll compressor of claim 15, wherein the valve support
encloses the discharge opening, and the plurality of valve bodies
extend inwardly from the valve support in a radial direction.
17. The scroll compressor of claim 15, wherein the valve support
extends in a `V` shape.
18. The scroll compressor of claim 15, wherein the valve support is
fixed by a coupling member that couples the back pressure assembly
and the second scroll to each other.
19. The scroll compressor of claim 15, wherein the valve support is
fixed to the second scroll by at least one rivet.
20. The scroll compressor of claim 1, further comprising a seal
that encloses the discharge path disposed between contact surfaces
of the back pressure chamber assembly and the second scroll.
21. The scroll compressor of claim 1, wherein the back pressure
chamber assembly comprises: a back pressure plate fastened to the
second scroll below the discharge cover, the back pressure plate
comprising a cavity with which the intermediate pressure chamber
communicates; and a floating plate movably coupled to the back
pressure plate so as to seal an upper portion of the cavity.
22. The scroll compressor of claim 21, wherein the back pressure
plate comprises: a supporting plate having a ring shape that
contacts an upper surface of the second scroll; a first ring-shaped
wall formed to enclose an inner space of the supporting plate; and
a second ring-shaped wall disposed at an outer circumference of the
first ring-shaped wall.
23. The scroll compressor of claim 22, further comprising a
plurality of bolt coupling holes formed on the supporting plate,
wherein the second scroll and the back pressure plate are fastened
by a corresponding number of bolts, which pass through the
plurality of bolt coupling holes.
24. The scroll compressor of claim 22, wherein the floating plate
is ring-shaped, and wherein the floating plate and the back
pressure plate are coupled such that an outer circumferential
surface of the first ring-shaped wall contacts an inner
circumferential surface of the floating plate and an inner
circumferential surface of the second ring-shaped wall contacts an
outer circumferential surface of the floating plate.
25. The scroll compressor of claim 22, wherein the second
ring-shaped wall is positioned at an outer circumferential surface
of the supporting plate.
26. The scroll compressor of claim 1, wherein a diameter of the
bypass hole is formed to be smaller than a thickness of a wrap of
the second scroll.
27. A scroll compressor, comprising: a casing comprising a suction
space and a discharge space; a first scroll that forms a suction
chamber, an intermediate pressure chamber, and a discharge chamber
together with a second scroll; a bypass hole and a bypass valve
configured to discharge an operation fluid outside of the second
scroll when pressure of the intermediate pressure chamber is higher
than a discharge pressure; a discharge path that communicates with
the discharge space; and a back pressure plate configured to
introduce the discharged operation fluid to the discharge path,
wherein the discharged operation fluid flows between facing
surfaces of the second scroll and the back pressure plate, to thus
reach the discharge path.
28. The scroll compressor of claim 27, wherein the back pressure
plate includes a groove formed therein and the floating plate is
movably disposed in the groove.
29. The scroll compressor of claim 28, wherein a lower surface of
the back pressure plate faces an upper surface of the second
scroll.
30. The scroll compressor of claim 29, wherein a bypass path is
formed between the lower surface of the back pressure plate and the
upper surface of the second scroll and extends in a lateral
direction.
31. The scroll compressor of claim 27, wherein the discharged
operation fluid flows along a groove formed in one of a lower
surface of the back pressure plate or an upper surface of the
second scroll, to thus reach the discharge path
32. The scroll compressor of claim 27, further comprising a
restrictor that restricts an open degree of the bypass valve.
33. The scroll compressor of claim 32, wherein the restrictor is
formed on a lower surface of the back pressure plate.
34. The scroll compressor of claim 33, wherein the restrictor
comprises a retainer disposed on a lower surface of the back
pressure plate.
35. The scroll compressor of claim 27, wherein a bypass path is
defined by a groove concaved from a lower surface of the back
pressure plate, and an upper surface of the second scroll, and
wherein the bypass valve is configured to open and close the bypass
hole via a movement within the groove.
36. The scroll compressor of claim 35, wherein the movement of the
bypass valve is restricted by an inner surface of the groove.
37. The scroll compressor of claim 27, wherein a bypass path is
defined by a groove concaved from an upper surface of the second
scroll and a lower surface of the back pressure plate, and wherein
the bypass valve is configured to open and close the bypass hole
via a movement within the groove.
38. The scroll compressor of claim 37, wherein the movement of the
bypass valve is restricted by an inner surface of the groove.
39. The scroll compressor of claim 27, wherein the bypass valve
comprises: a valve body configured to cover the bypass hole; and a
valve support configured to fix the valve body between the second
scroll and the back pressure plate.
40. The scroll compressor of claim 39, wherein the valve body
comprises a plurality of valve bodies.
41. The scroll compressor of claim 40, wherein the valve support
encloses the discharge opening, and the plurality of valve bodies
extend inwardly from the valve support in a radial direction.
42. The scroll compressor of claim 40, wherein the valve support
extends in a `V` shape.
43. The scroll compressor of claim 40, wherein the valve support is
fixed by a coupling member that couples the back pressure plate and
the second scroll to each other.
44. The scroll compressor of claim 40, wherein the valve support is
fixed to the second scroll by at least one rivet.
45. The scroll compressor of claim 27, further comprising a seal
that encloses the discharge path disposed between contact surfaces
of the back pressure plate and the second scroll.
46. The scroll compressor of claim 27, wherein the back pressure
plate comprises: a supporting plate having a ring shape that
contacts an upper surface of the second scroll; a first ring-shaped
wall formed to enclose an inner space of the supporting plate; and
a second ring-shaped wall disposed at an outer circumference of the
first ring-shaped wall.
47. The scroll compressor of claim 46, further comprising a
plurality of bolt coupling holes formed on the supporting plate,
wherein the second scroll and the back pressure plate are fastened
by a corresponding number of bolts, which pass through the
plurality of bolt coupling holes.
48. The scroll compressor of claim 46, further comprising a
ring-shaped floating plate, wherein the floating plate and the back
pressure plate are coupled such that an outer circumferential
surface of the first ring-shaped wall contacts an inner
circumferential surface of the floating plate and an inner
circumferential surface of the second ring-shaped wall contacts an
outer circumferential surface of the floating plate.
49. The scroll compressor of claim 46, wherein the second
ring-shaped wall is positioned at an outer circumferential surface
of the supporting plate.
50. The scroll compressor of claim 27, wherein a diameter of the
bypass hole is formed to be smaller than a thickness of a wrap of
the second scroll.
51. A scroll compressor, comprising: a casing; a discharge cover,
the discharge cover dividing an inner space of the casing into a
suction space and a discharge space; a main frame, the main frame
being spaced apart from the discharge cover; a first scroll
supported by the main frame, the first scroll performing an orbital
motion with respect to a rotational shaft thereof in operation; a
second scroll that forms a suction chamber, an intermediate
pressure chamber, and a discharge chamber together with the first
scroll, the second scroll being movable with respect to the first
scroll and comprising a bypass hole that communicates with the
intermediate pressure chamber; a back pressure chamber assembly
coupled to the second scroll, the back pressure chamber assembly
comprising a back pressure plate and a floating plate and being
configured to press the second scroll toward the first scroll, the
back pressure chamber assembly further having a discharge path by
which the discharge chamber and the discharge space with
communicate with each other; and a bypass valve that opens and
closes the bypass hole, wherein the back pressure plate comprises a
back pressure cavity formed by inner and outer circumferential
walls, and wherein the bypass hole is formed in the second scroll
at a position outwardly spaced from the inner circumferential wall
in a radial direction.
52. The scroll compressor of claim 51, wherein a lower surface of
the back pressure plate faces an upper surface of the second
scroll.
53. The scroll compressor of claim 52, wherein a bypass path is
formed between the lower surface of the back pressure plate and the
upper surface of the second scroll and extends in a lateral
direction.
54. The scroll compressor of claim 53, wherein the bypass path
includes a groove formed in one of the lower surface of the back
pressure plate or the upper surface of the second scroll.
55. The scroll compressor of claim 51, wherein the bypass valve is
opened and closed by a pressure difference between the intermediate
pressure chamber and the discharge space.
56. The scroll compressor of claim 51, further comprising a
restrictor that restricts an open degree of the bypass valve.
57. The scroll compressor of claim 56, wherein the restrictor is
formed on a lower surface of the back pressure chamber
assembly.
58. The scroll compressor of claim 56, wherein the restrictor
comprises a retainer disposed on a lower surface of the back
pressure chamber assembly.
59. The scroll compressor of claim 51, wherein a bypass path is
defined by a groove concaved from a lower surface of the back
pressure plate, and an upper surface of the second scroll, and
wherein the bypass valve is configured to open and close the bypass
hole via a movement within the groove.
60. The scroll compressor of claim 59, wherein the movement of the
bypass valve is restricted by an inner surface of the groove.
61. The scroll compressor of claim 51, wherein a bypass path is
defined by a groove concaved from an upper surface of the second
scroll and a lower surface of the back pressure plate, and wherein
the bypass valve is configured to open and close the bypass hole
via a movement within the groove.
62. The scroll compressor of claim 61, wherein the movement of the
bypass valve is restricted by an inner surface of the groove.
63. The scroll compressor of claim 51, wherein the bypass valve
comprises: a valve body configured to cover the bypass hole; and a
valve support configured to fix the valve body between the second
scroll and the back pressure plate.
64. The scroll compressor of claim 63, wherein the valve body
comprises a plurality of valve bodies.
65. The scroll compressor of claim 64, wherein the valve support
encloses the discharge opening, and the plurality of valve bodies
extend inwardly from the valve support in a radial direction.
66. The scroll compressor of claim 64, wherein the valve support
extends in a `V` shape.
67. The scroll compressor of claim 64, wherein the valve support is
fixed by a coupling member that couples the back pressure plate and
the second scroll to each other.
68. The scroll compressor of claim 64, wherein the valve support is
fixed to the second scroll by at least one rivet.
69. The scroll compressor of claim 51, further comprising a seal
that encloses the discharge path disposed between contact surfaces
of the back pressure plate and the second scroll.
70. The scroll compressor of claim 51, wherein the back pressure
plate comprises: a supporting plate having a ring shape that
contacts an upper surface of the second scroll; a first ring-shaped
wall formed to enclose an inner space of the supporting plate; and
a second ring-shaped wall disposed at an outer circumference of the
first ring-shaped wall.
71. The scroll compressor of claim 70, further comprising a
plurality of bolt coupling holes formed on the supporting plate,
wherein the second scroll and the back pressure plate are fastened
by a corresponding number of bolts, which pass through the
plurality of bolt coupling holes.
72. The scroll compressor of claim 70, wherein the floating plate
is ring-shaped, and wherein the floating plate and the back
pressure plate are coupled such that an outer circumferential
surface of the first ring-shaped wall contacts an inner
circumferential surface of the floating plate and an inner
circumferential surface of the second ring-shaped wall contacts an
outer circumferential surface of the floating plate.
73. The scroll compressor of claim 70, wherein the second
ring-shaped wall is positioned at an outer circumferential surface
of the supporting plate.
74. The scroll compressor of claim 51, wherein a diameter of the
bypass hole is formed to be smaller than a thickness of a wrap of
the second scroll.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims priority to Korean Application Nos.
10-2013-0028775, filed in Korea on Mar. 18, 2013, 10-2013-0028783
filed in Korea on Mar. 18, 2013, and 10-2013-0028791, filed in
Korea on Mar. 18, 2013, as well as U.S. application Ser. Nos.
______ (Attorney Docket No. P-1232) filed in the U.S. on ______,
and ______ (Attorney Docket No. P-1236), filed in the U.S. on
______, the contents of all of which are incorporated by reference
herein in their entirety.
BACKGROUND
[0002] 1. Field
[0003] A compressor, and more particularly, a scroll compressor
with a bypass are disclosed herein.
[0004] 2. Background
[0005] Scroll compressors are known. However, they suffer from
various disadvantages.
[0006] A scroll compressor refers to a compressor that utilizes a
first or orbital scroll having a spiral wrap and a second or fixed
scroll having a spiral wrap, the first scroll performing an orbital
motion with respect to the second scroll. While the first scroll
and the second scroll are engaged with each other in operation, a
capacity of a pressure chamber formed therebetween may be reduced
as the first scroll performs the orbital motion. Hence, the
pressure of a fluid in the pressure chamber may be increased, and
the fluid discharged from a discharge opening formed at a central
portion of the second scroll.
[0007] The scroll compressor performs a suction process, a
compression process, and a discharge process consecutively while
the first scroll performs the orbital motion. Because of
operational characteristics, the scroll compressor may not require
a discharge valve and a suction valve in principle, and its
structure may be simple with a small number of components, thus
making it possible to perform a high speed rotation. Further, as
the change in torque required for compression is small and the
suction and compression processes consecutively performed, the
scroll compressor is known to create minimal noise and
vibration.
[0008] For the scroll compressor, an occurrence of leakage of a
refrigerant between the first scroll and the second scroll should
be avoided or kept at a minimum, and lubricity (lubrication
characteristic) should be enhanced therebetween. In order to
prevent a compressed refrigerant from leaking between the first
scroll and the second scroll, an end of a wrap portion should be
adhered to a surface of a plate portion. On the other hand, in
order for the first scroll to smoothly perform an orbital motion
with respect to the second scroll, resistance due to friction
should be minimized. The relationship between the prevention of the
refrigerant leakage and the enhancement of the lubricity is
contradictory. That is, if the end of the wrap portion and the
surface of the plate portion are adhered to each other with an
excessive force, leakage may be prevented. However, in such a case,
more friction between the parts may result, thereby increasing
noise and abrasion. On the other hand, if the end of the wrap
portion and the surface of the plate portion are adhered to each
other with less than an adequate sealing force, the friction may be
reduced, but the lowering of the sealing force may result in the
increase of leakage.
[0009] In order to solve such problems, a back pressure chamber
having an intermediate pressure between a discharge pressure and a
suction pressure may be formed on a rear surface of the first
scroll or the second scroll. That is, the first scroll and the
second scroll may be adhered to each other with proper force, by
forming a back pressure chamber that communicates with a
compression chamber having an intermediate pressure, among a
plurality of compression chambers formed between the first scroll
and the second scroll. With such a configuration, leakage of
refrigerant may be prevented and lubricity enhanced.
[0010] The back pressure chamber may be positioned on a lower
surface of the first scroll or an upper surface of the second
scroll. In this case, the scroll compressor with such a back
pressure chamber may be referred to as a `lower back pressure type
scroll compressor` or an `upper back pressure type scroll
compressor` for convenience. The structure of the lower back
pressure type scroll compressor is simple, and its bypass holes
easily formed. However, as its back pressure chamber is positioned
on the lower surface of the first scroll, the form and position of
the back pressure chamber may change due to the orbital motion.
This may cause the first scroll to tilt, resulting in the
occurrence of vibration and noise. Further, an O-ring to prevent
leakage of a compressed refrigerant may be rapidly abraded. The
structure of the upper back pressure type scroll compressor is
complicated. However, as the back pressure chamber of the upper
back pressure type scroll compressor is fixed in form and position,
the probability of the second scroll tilting is low, and sealing
for the back pressure chamber is excellent.
[0011] Korean Patent Application No. 10-2000-0037517 entitled
Method For Processing Bearing Housing and Scroll Machine having
Bearing Housing, which corresponds to U.S. Pat. No. 5,156,539 and
U.S. Reissue Pat. No. 35,216, all of which are hereby incorporated
by reference, discloses an example of such an upper back pressure
type scroll compressor. FIG. 1 is a partial cross-sectional view of
an upper back pressure type scroll compressor. The scroll
compressor 1 of FIG. 1 may include a first or orbital scroll 30
configured to perform an orbital motion on a main frame 20
fixedly-installed in a casing 10 and a second or fixed scroll 40
engaged with the first scroll 30 to create a plurality of
compression chambers upon the orbital motion. A back pressure
chamber BP may be formed at an upper portion of the second scroll
40, and a floating plate 60 to seal the back pressure chamber BP
may be installed so as to be slidable up and down along an outer
circumferential surface of a discharge passage 45. A discharge
cover 2 may be installed at an upper surface of the floating plate
60, thereby dividing an inner space of the scroll compressor 1 into
a suction space (S) and a discharge space (D). A lip seal (not
shown) may be installed between the floating plate 60 and the back
pressure chamber BP, so that refrigerant may be prevented from
leaking from the back pressure chamber BP.
[0012] The back pressure chamber BP may communicate with one of the
plurality of compression chambers, and may be at a receiving end of
an intermediate pressure from the plurality of compression
chambers. With such a configuration, pressure may be applied upward
to the floating plate 60, and pressure may also be applied downward
to the second scroll 40. If the floating plate 60 moves upward due
to pressure of the back pressure chamber BP, the discharge space D
may be sealed as an end of the floating plate 60 contacts the
discharge cover 2. In this case, the second scroll 40 moves
downward to be adhered to the first scroll 30. With such a
configuration, a gap between the second scroll 40 and the first
scroll 30 may be effectively sealed.
[0013] Korean Patent Application No. 10-2012-7023733, which
corresponds to U.S. Patent Pub. No. 2011/0206548, both of which are
hereby incorporated by reference, discloses a compressor having a
valve assembly. FIG. 2 is a sectional view of a fixed or second
scroll of an upper back pressure type scroll compressor. The
compressor of FIG. 2 may include a hub member 76 positioned at a
central portion of the back pressure chamber BP and formed to pass
through the back pressure chamber BP in upper and lower directions,
and a valve assembly 28 disposed below the hub member 76. With such
a configuration, bypass holes 90 and 92 formed on an upper surface
of the second scroll 40 may be open and closed while the valve
assembly 28 moves the hub member 76 up and down. For example, the
bypass holes 90 and 92 may be open when the intermediate pressure
is higher than the discharge pressure, thus pushing the valve
assembly 28 up. Accordingly, overload in the upper back pressure
type scroll compressor may be prevented by alleviating the pressure
imbalance using the bypass holes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Embodiments will be described in detail with reference to
the following drawings in which like reference numerals refer to
like elements, and wherein:
[0015] FIG. 1 is a cross-sectional view of an upper back pressure
type scroll compressor;
[0016] FIG. 2 is a cross-sectional view of a second scroll of an
upper back pressure type scroll compressor;
[0017] FIG. 3 is a cross-sectional view of an upper back pressure
type scroll compressor having a back pressure discharge according
an embodiment;
[0018] FIG. 4 is a partial cut-out perspective view showing a
coupled state between a second scroll and a back pressure chamber
assembly of FIG. 3;
[0019] FIG. 5 is an exploded perspective view of the second scroll
and the back pressure chamber assembly of FIG. 3;
[0020] FIG. 6 is a perspective view of the second scroll of FIG.
3;
[0021] FIG. 7 is a planar view of a lower surface of a back
pressure plate of FIG. 3;
[0022] FIG. 8 is an enlarged cross-sectional view of a portion of
the second scroll and the back pressure plate of FIG. 3;
[0023] FIG. 9 is a partial cut-out cross-sectional view for
explaining operation of a check valve and a discharge valve of FIG.
3;
[0024] FIG. 10 is a partial cut-out view of the scroll compressor
of FIG. 3 with a retainer according to an embodiment;
[0025] FIG. 11 is a perspective view of a bypass valve according to
another embodiment;
[0026] FIG. 12 is a cross-sectional view of a bypass valve
according to another embodiment; and
[0027] FIG. 13 is a perspective view of a bypass valve according to
yet another embodiment.
DETAILED DESCRIPTION
[0028] Description will now be given in detail of embodiments, with
reference to the accompanying drawings. Where possible, like
reference numerals have been utilized to indicate like elements,
and repetitive disclosure has been omitted.
[0029] Referring again to FIG. 2, overload in the upper back
pressure type scroll compressor may be prevented by alleviating
pressure imbalance using the bypass holes and associated components
of the scroll compressor. However, as the hub member 76 may be
disposed in the back pressure chamber BP, the position of the
bypass holes 90, 92 may not be set arbitrarily. That is, in order
to obtain a sufficient back pressure with the back pressure chamber
BP, the back pressure chamber BP should be formed at a
predetermined position with a predetermined size. This may limit a
size of the hub member 76. Therefore, positions of the bypass holes
90, 92 may be restricted to a region below the hub member 76.
[0030] Further, the floating plate 60 should seal the back pressure
chamber BP while contacting an inner surface of the back pressure
chamber BP of the second scroll 40 and an outer circumferential
surface of the hub member 76. In this case, a sealing performance
of the floating plate 60 may be compromised due to a quality of
surface processing performed on the outer circumferential surface
of the hub member 76, that is a processing allowance (tolerance)
and a coupling allowance (tolerance) of the hub member 76.
[0031] Therefore, embodiments disclosed herein further provide a
scroll compressor capable of forming bypass holes at arbitrary
positions of the second scroll. Embodiments disclosed herein
further provide a scroll compressor capable of using a bypass valve
of a simple structure.
[0032] FIG. 3 is a cross-sectional view of an upper back pressure
type scroll having a bypass according to an embodiment. FIG. 4 is a
partial cut-out perspective view showing a coupled state between a
second scroll and a back pressure chamber assembly of FIG. 3. FIG.
5 is an exploded perspective view of the second scroll and the back
pressure chamber assembly of FIG. 3.
[0033] Referring to FIG. 3, a scroll compressor 100 having a bypass
according to an embodiment may include a casing 110 having a
suction space (S) and a discharge space (D), which are discussed
hereinbelow. An inner space of the casing 110 may be divided into
the suction space (S) and the discharge space (D) by a discharge
cover 102 installed above at an upper portion of the casing 110. A
space above the discharge cover 102 may correspond to the discharge
space (D), and a space below the discharge cover 102 may correspond
to the suction space (S). A suction port (not shown) that
communicates with the suction space (S) and a discharge port (not
shown) that communicates with the discharge space (D) may be fixed
to the casing 110, respectively, thereby sucking a refrigerant into
the casing 110 or discharging a refrigerant outside of the casing
110, respectively.
[0034] A stator 112 and a rotor 114 may be provided below the
suction space (S). The stator 112 may be fixed to an inner wall
surface of the casing 110, for example, in a shrinkage fitting
manner. A rotational shaft 116 may be inserted into a central
portion of the rotor 114, and may be rotated by power supplied from
the outside.
[0035] A lower side of the rotational shaft 116 may be rotatably
supported by an auxiliary bearing 117 installed below at a lower
portion of the casing 110. The auxiliary bearing 117 may be
supported by a lower frame 118 fixed to an inner surface of the
casing 110, thereby stably supporting the rotational shaft 116. The
lower frame 118 may be fixed to an inner wall surface of the casing
110, for example, by welding, and a bottom lower surface of the
casing 110 may be used as an oil storage space. Oil stored in the
oil storage space may be upward transferred upward by the
rotational shaft 116, so that the oil may be uniformly supplied
into the casing 110.
[0036] An upper end of the rotational shaft 116 may be rotatably
supported by a main frame 120. The main frame 120 may be fixed to
an inner wall surface of the casing 110, similar to the lower frame
118. A main bearing portion 122 may protrude downward from a lower
surface of the main frame 120, and the rotational shaft 116 may be
inserted into the main bearing portion 122. An inner wall surface
of the main bearing portion 122 may serve as a bearing surface and
support the rotational shaft 116 together with the aforementioned
oil, so that the rotational shaft 116 may rotate in a smooth
manner.
[0037] A first or orbital scroll 130 may be disposed on an upper
surface of the main frame 120. The first scroll 130 may include a
plate portion 132, which may have an approximate disc shape, and a
wrap 134 spirally formed on one side surface of the plate portion
132. The wrap 134 may form a plurality of compression chambers
together with a wrap 144 of a fixed or second scroll 140, which is
discussed hereinbelow. The plate portion 132 of the first scroll
130 may perform an orbital motion while supported by an upper
surface of the main frame 120. An Oldham ring 136 may be installed
between the plate portion 132 and the main frame 120, thereby
preventing rotation of the first scroll 130. A boss portion 138,
into which the rotational shaft 116 may be inserted, may be formed
on a lower surface of the plate portion 132 of the first scroll
130, thus allowing the first scroll 130 to perform an orbital
motion by a rotational force of the rotational shaft 116.
[0038] The second scroll 140, which engages the orbital scroll 130,
may be disposed above the first scroll 130. The second scroll 140
may be installed to be movable up and down with respect to the
first scroll 130. More specifically, the second scroll 140 may be
disposed on an upper surface of the main frame 120 using, for
example, a fastener, for example, three guide pins 104, fitted into
the main frame 120 inserted into three (3) guide holes 141 formed
on an outer circumference of the second scroll 140.
[0039] The guide holes 141 may be formed at three pin supporting
portions 142 that protrude from an outer circumferential surface of
a body portion of the second scroll 140. The number of the guide
pins 104 or pin supporting portions 142 may be arbitrarily set, and
thus, the number is not limited to three.
[0040] The second scroll 140 may include a plate portion 143, which
may have a disc shape. The wrap 144, which engages the wrap 134 of
the first scroll 130, may be formed below the plate portion 143.
The wrap 144 may have a spiral shape, and a discharge opening 145,
through which a compressed refrigerant may be discharged, may be
formed at a central portion of the plate portion 143. A suction
opening 146, through which a refrigerant disposed in the suction
space (S) may be sucked, may be formed on a side surface of the
second scroll 140, so that the refrigerant may be sucked to the
suction opening 146 by an interaction between the wrap 144 and the
wrap 134.
[0041] As discussed above, the wrap 144 and the wrap 134 form a
plurality of compression chambers. As the plurality of compression
chambers decrease in volume while orbiting toward the discharge
opening 145, a refrigerant is compressed. As a result, a pressure
of a compression chamber adjacent to the suction opening 146 may be
minimized, and a pressure of a compression chamber that
communicates with the discharge opening 145 may be maximized. A
pressure of a compression chamber positioned between the two
above-mentioned compression chambers may have an intermediate
pressure halfway between a suction pressure adjacent the suction
opening 146 and a discharge pressure adjacent the discharge opening
145. The intermediate pressure may be applied to a back pressure
chamber (BP), which is discussed hereinbelow, and may press the
second scroll 140 toward the first scroll 130. Therefore, an
intermediate pressure discharge opening 147, which may communicate
with one of the intermediate pressure chambers, and through which a
refrigerant may be discharged, may be formed at the plate portion
143, referring to FIG. 5.
[0042] An intermediate pressure sealing groove 147a, into which an
intermediate pressure O-ring 147b that prevents leakage of a
discharged refrigerant having the intermediate pressure may be
inserted, may be formed near the intermediate pressure discharge
opening 147. The intermediate pressure sealing groove 147a may be
formed in an approximately circular shape to enclose the
intermediate pressure discharge opening 147. However, the shape is
not limited to the circular shape. Further, the intermediate
pressure sealing groove 147a may be formed at other than the plate
portion 143 of the fixed scroll 140. For instance, the intermediate
pressure sealing groove 147a may be formed on a lower surface of a
back pressure plate 150, which is discussed hereinbelow.
[0043] Bolt coupling holes 148 for coupling bolts 106, which couple
the back pressure plate 150 and the second scroll 140, may be
formed on the plate portion 143 of the second scroll 140. In this
embodiment, the number of the bolt coupling holes 148 is four, but
embodiments are not so limited.
[0044] Referring to FIG. 6, bypass holes 149 may be formed at both
sides of the discharge opening 145. The bypass holes 149 may pass
through the plate portion 143, and extend up to the plurality of
compression chambers formed by the wrap 144 and the wrap 134. The
position of the bypass holes 149 may be differently set according
to an operating condition. The bypass holes 149 may be formed to
communicate with the compression chambers having a pressure 1.5
times higher than the suction pressure. The bypass holes 149 may
include two through-holes, and a wall portion 149a that encloses an
outer circumferential portion of the two through-holes may be
provided. The wall portion 149a may contact a valve body of a
bypass valve, which is discussed hereinbelow, and the wall portion
149a may provide a space in which a refrigerant discharged from the
through-holes may stay temporarily.
[0045] A valve seat portion 149b may be formed near the bypass hole
149. The valve seat portion 149b may provide a space through or in
which a valve supporting portion of a bypass valve, which is
discussed hereinbelow, may move, and may extend from an outer
circumferential portion of the wall portion 149a in one
direction.
[0046] Referring to FIG. 5, the bypass valve 124 may include a
valve supporting portion 124a fixed to the plate portion 143 of the
second scroll 140 by, for exmaple, rivets. The valve supporting
portion 124a may have a circular arc shape, and may be fixed to the
plate portion 143 by, for example, two rivets. Alternatively, a
coupling device such as bolts or screws, rather than the rivets,
may be used. The valve supporting portion 124a may extend from
portions to which the rivets are coupled in a `V` shape. For
convenience, the extending portions may be referred to as
connection portions 124b. Valve bodies 124c may be formed at ends
of the connection portions 124b. The valve body 124c may maintain
contact with the wall portion 149a when no external force is
applied thereto, and may have a diameter large enough to completely
cover the wall portion 149a.
[0047] A back pressure chamber assembly may be installed on the
plate portion 143 of the second scroll 140. The back pressure
chamber assembly may include a back pressure plate 150 and a
floating plate 160, and may be fixed to an upper portion of the
plate portion 143 of the second scroll 143. The back pressure plate
150 may have a ring shape, and may include a supporting plate 152
that contacts the plate portion 143 of the second scroll 140. The
supporting plate 152 may have a ring shape, and may be formed to
allow an intermediate pressure suction opening 153 that
communicates with the aforementioned intermediate pressure
discharge opening 147 to pass therethrough, referring to FIG. 7.
Further, bolt coupling holes 154 that communicate with the bolt
coupling holes 148 of the plate portion 143 of the second scroll
140 may be formed at or in the supporting plate 152.
[0048] An O-ring 155a may be disposed between a lower surface of
the supporting plate 152 and an upper surface of the second scroll
140. The O-ring 155a, which may prevent a refrigerant from leaking
from a gap between the supporting plate 152 and the second scroll
140, may be fitted into a ring-shaped groove 155 formed on an upper
surface of the second scroll 140. Further, the O-ring 155a may be
forcibly pressed while the second scroll 140 and the back pressure
plate 150 are coupled to each other by the bolts 106, thereby
sealing a gap between the second scroll 140 and the back pressure
plate 150. Alternatively, the ring-shaped groove 155 may be formed
on a lower surface of the supporting plate 152, rather than on the
second scroll 140.
[0049] The back pressure plate 150 may include a first ring-shaped
wall 158 and a second ring-shaped wall 159 formed to enclose an
inner circumferential surface and an outer circumferential surface
of the supporting plate 152, respectively. The first ring-shaped
wall 158 and the second ring-shaped wall 159 may form a space
having a specific shape together with the supporting plate 152. The
space may implement the aforementioned back pressure chamber (BP).
The first ring-shaped wall 158 may extend upward from a central
portion of the supporting plate 152, and include an upper surface
158a may cover an upper end of the first ring-shaped wall 158. The
first ring-shaped wall 158 may have a cylindrical shape with an
open end.
[0050] An inner space of the first ring-shaped wall 158 may
communicate with the discharge opening 145, thereby implementing a
portion of a discharge path along which a discharged refrigerant
may be transferred to the discharge space (D). As shown in FIGS. 4
and 9, a discharge check valve 108, which may have a cylindrical
shape, may be disposed above the discharge opening 145. More
specifically, a lower end of the discharge check valve 108 may be
large enough to completely cover the discharge opening 145. With
such a configuration, in a case in which the discharge check valve
108 contacts the plate portion 143 of the second scroll 140, the
discharge check valve 108 may block the discharge opening 145.
[0051] The discharge check valve 108 may be installed in a valve
guide portion 158b formed at an inner space of the first
ring-shaped wall 158, and the valve guide portion 158b may guide an
up-and-down motion of the discharge check valve 108. The valve
guide portion 158b may pass through the inner space of the first
ring-shaped wall 158. An inner diameter of the valve guide portion
158b may be the same as an outer diameter of the discharge check
valve 108, to guide an up-and-down motion of the discharge check
valve 108 above the discharge opening 145. However, the inner
diameter of the valve guide portion 158b may not be completely
equal to the outer diameter of the discharge check valve 108 to
facilitate movement of the discharge check valve 108.
[0052] A discharge pressure applying hole 158c that communicates
with the valve guide portion 158b may be formed at a central
portion of an upper surface of the first ring-shaped wall 158. The
discharge pressure applying hole 158c may communicate with the
discharge space (D). Accordingly, in a case in which a refrigerant
from the discharge space (D) backflows to the discharge opening
145, pressure applied to the discharge pressure applying hole 158c
may become higher than the pressure of the discharge opening 145.
As a result, the discharge check valve 108 may move downward to
block the discharge opening 145. If the pressure at the discharge
opening 145 increases to be higher than the pressure at the
discharge space (D), the discharge check valve 108 may move upward
to open the discharge opening 145.
[0053] One or more intermediate discharge opening(s) 158d may be
formed outside of the valve guide portion 158b. The one of more
intermediate discharge opening(s) 158d may provide a path through
which a refrigerant discharged from the discharge opening 145 may
move to the discharge space (D). In this embodiment, four (4)
intermediate discharge openings 158d are radially disposed;
however, the number of the intermediate discharge openings 158d may
vary. The one or more intermediate discharge opening(s) 158d may
pierce through the first ring-shaped wall 158 extending from its
bottom to its top. The one or more intermediate discharge
opening(s) 158d and the valve guide portion 158b may communicate
with each other at a lower end of the back pressure plate 150. That
is, a stepped portion 158e may be formed in a connection portion
between the first ring-shaped wall 158 and the supporting plate
152. A discharged refrigerant reaches a space defined by the
stepped portion 158e, and then moves to the one or more
intermediate discharge opening(s) 158d.
[0054] A groove portion 161 to form a bypass path may be formed
outside the stepped portion 158e in a radial direction. The groove
portion 161 may have a circular arc shape to enclose a portion of
an outer circumferential portion of the stepped portion 158e, and
may be concaved from a lower surface of the supporting plate 152.
Along an outer circumferential portion of the groove portion 161
extending in a radial direction, regions adjacent to the bolt
coupling holes 154 may protrude inward in a radial direction. This
may allow a peripheral portion of the bolt coupling holes 154 to
maintain a sufficient strength.
[0055] An inner circumferential portion of the groove portion 161
in the radial direction may be open towards the stepped portion
158e. With such a configuration, an inner space of the groove
portion 161 may communicate with the one or more intermediate
discharge opening(s) 158d via the stepped portion 158e.
[0056] A portion 161a of an upper surface of the groove portion 161
(bottom surface in FIG. 7) may restrict an upward motion of the
valve body 124c, which may be referred to as an open degree
restrictor 161a for convenience. The open degree restrictor 161a
may be in a shape corresponding to the valve body 124c, and may
protrude toward the stepped portion 158e. The open degree
restrictor 161a may be positioned above the valve body 124c.
Accordingly, in a case in which the valve body 124c moves upward by
a distance more than a predetermined value, the valve body 124c may
contact the open degree restrictor 161a to prevent the valve body
124c from moving any further.
[0057] Instead of the open degree restrictor, an additional
retainer may be provided. As shown in FIG. 10, a retainer 161b to
restrict an open degree of the valve body 124c when the valve body
124c is open may be formed on an upper surface of the groove
portion 161.
[0058] In some cases, the stepped portion 158e may not be provided,
but rather, a communication hole to communicate the valve guide
portion 158b and the one or more intermediate discharge opening(s)
158d with each other may be provided. In any case, a refrigerant
having passed through the discharge opening 145 may not be
discharged to the one or more intermediate discharge opening(s)
158d if the discharge check valve 108 is closed. The stepped
portion 158e may be formed in the plate portion 143 of the second
scroll 140, rather than on the back pressure plate 150.
[0059] The groove portion may be formed on an upper surface of the
plate portion 143 of the second scroll 140, rather than on a lower
surface of the supporting plate. In such a case, the bypass hole
and the bypass valve may be formed on a bottom surface of the
groove portion. With such a configuration, a length of the bypass
hole may be shortened, and thus a dead volume formed by the bypass
hole may be reduced.
[0060] The second ring-shaped wall 159 may be spaced from the first
ring-shaped wall 158 by a predetermined distance, and a first
sealing insertion groove 159a may be formed on an inner
circumferential surface of the second ring-shaped wall 159. The
first sealing insertion groove 159a may serve to receive and fix an
O-ring 159b, to prevent leakage of a refrigerant from a contact
surface to a floating plate 160, which is discussed hereinbelow.
Alternatively, the first sealing insertion groove 159a may be
formed on an outer circumferential surface of the floating plate
160. However, the first sealing insertion groove 159a formed on the
floating plate 160 may be less stable than the first sealing
insertion groove 159a formed on the back pressure plate 150,
because the floating plate 160 continuously moves up and down.
[0061] A space having an approximately `U`-shaped section may be
formed by the first ring-shaped wall 158, the second ring-shaped
wall 159, and the supporting plate 152. The floating plate 160 may
be installed to cover the space. The floating plate 160 may have a
ring shape, and be configured such to have an inner circumferential
surface thereof face an outer circumferential surface of the first
ring-shaped wall 158, and to have an outer circumferential surface
thereof face an inner circumferential surface of the second
ring-shaped wall 159. With such a configuration, the back pressure
chamber (BP) may be implemented, and the aforementioned O-rings
159b and 162a interposed between the respective facing surfaces may
serve to prevent a refrigerant inside the back pressure chamber
(BP) from leaking to the outside. Further, bolt accommodation
portions 106a, which may prevent interference with the bolts 106,
may be formed on a lower surface of the floating plate 160.
However, in a case in which heads of the bolts 106 do not protrude
from a surface of the supporting plate 152, the bolt accommodation
portion 106a may be omitted.
[0062] A second sealing insertion groove 162 to receive and fix the
O-ring 162a may be formed on the inner circumferential surface of
the floating plate 160. The second sealing insertion groove 162 may
be provided at or in the inner circumferential surface of the
floating plate 160, whereas the first sealing insertion groove 159a
may be formed or in at the second ring-shaped wall 159. This is
because the first ring-shaped wall 158 may have an insufficient
margin to process the grooves due to the valve guide portion 158b
and the one or more intermediate discharge opening(s) 158d formed
therein, and a diameter of the first ring-shaped wall 158 may be
smaller than a diameter the second ring-shaped wall 159.
Alternatively, if the first ring-shaped wall 158 has a large
diameter and a sufficient margin to process the grooves, the second
sealing insertion groove 162 may be formed in the first ring-shaped
wall 158.
[0063] A sealing end 164 may be provided at an upper end of the
floating plate 160. The sealing end 164 may protrude upward from
the surface of the floating plate 160, and may have an inner
diameter large enough not to cover the one or more intermediate
discharge opening(s) 158d. The sealing end 164 may contact a lower
side surface of the discharge cover 102, thereby sealing the
discharge path so that a discharged refrigerant may be discharged
to the discharge space (D) without leaking to the suction space
(S).
[0064] Hereinafter, an operation of a compressor according to an
embodiment will be explained.
[0065] When power is supplied to the stator 112, the rotational
shaft 116 may rotate. As the rotational shaft 116 rotates, the
first scroll 130 fixed to the upper end of the rotational shaft 116
may perform an orbital motion with respect to the second scroll
140. As a result, the plurality of compression chambers formed
between the wrap 144 and the wrap 134 may move toward the discharge
opening 145, thereby compressing a refrigerant.
[0066] If the plurality of compression chambers communicate with
the intermediate pressure discharge opening 147 before the
refrigerant reaches the discharge opening 145, a portion of the
refrigerant may be introduced into the intermediate pressure
suction opening 153 of the supporting plate 152. Accordingly, an
intermediate pressure may be applied to the back pressure chamber
(BP) formed by the back pressure plate 150 and the floating plate
160. As a result, pressure may be applied downward to the back
pressure plate 150, whereas pressure may be applied upward to the
floating plate 160.
[0067] Since the back pressure plate 150 may be coupled to the
second scroll 140 by, for example, bolts, an intermediate pressure
of the back pressure chamber (BP) may also influence the second
scroll 140. The floating plate 160 may move upward because the
second scroll 140 cannot move downward due to contact with the
plate portion 132 of the first scroll 130. As the sealing end 164
contacts the lower end of the discharge cover 102, the floating
plate 160 stops moving. Then, as the second scroll 140 is pushed
toward the first scroll 130 by the pressure of the back pressure
chamber (BP), the refrigerant may be prevented from leaking from a
gap between the first scroll 130 and the second scroll 140.
[0068] If a pressure of the discharge opening 145 becomes higher
than a pressure of the discharge space (D), the discharge check
valve 108 may move upward so that the refrigerant may be discharged
to the space defined by the stepped portion 158e. Then, the
refrigerant may be introduced into the one or more intermediate
discharge opening(s) 158d, and may then be discharged to the
discharge space (D). If the scroll compressor 100 is stopped or a
pressure of the discharge space (D) temporarily increases, the
discharge check valve 108 may move downward to block the discharge
opening 145. This may prevent counter rotation of the second scroll
140 resulting from backflow of the refrigerant.
[0069] As the groove portion 161 communicates with the discharge
path via the stepped portion 158e, a discharge pressure may be
applied to the groove portion 161. Pressure of the intermediate
pressure chamber may be applied to a lower surface of the valve
body 124c. In a normal operating condition, the valve body 124c may
maintain a contact state to the wall portion 149a and the bypass
hole 149 may be closed, because the discharge pressure is greater
than the intermediate pressure.
[0070] However, if the suction pressure increases due to a change
in operating condition, the intermediate pressure, which is
normally about 1.5 times higher than the suction pressure, may
become higher than the discharge pressure. In a case of the scroll
compressor, the discharge pressure has a value obtained by
multiplying the suction pressure with a compression ratio, while
the compression ratio is fixed. Accordingly, if the suction
pressure exceeds a proper range, the discharge pressure may
excessively increases causing overload. In order to solve such an
overload problem, if the discharge pressure inside the intermediate
pressure chamber is excessive, refrigerant should be discharged
even if it has not yet reached the discharge chamber.
[0071] If the intermediate pressure increases to be higher than the
discharge pressure, the valve body 124c may move upward to open the
bypass hole 149. As the bypass hole 149 is opened, the refrigerant
disposed in the intermediate pressure chamber may be discharged
into the groove portion 161, and may then move to the discharge
space via the discharge path. With such a configuration, pressure
of the intermediate pressure chamber may be prevented from
excessively increasing.
[0072] An operating condition of a system to which a compressor,
for example, a scroll compressor, is to be applied may be
predetermined. Accordingly, a range of the suction pressure and the
discharge pressure of the compressor may be predicted. Based on the
predicted range, a position or positions where the intermediate
pressure chamber has an excessive pressure may be determined, and
overload may be solved by forming bypass holes at those
position(s).
[0073] In the conventional art, if optimum positions of the bypass
holes correspond to an outside of a hub member, the bypass holes
cannot be formed at the necessary positions. However, with this
embodiment, as the back pressure chamber assembly may be separated
from the fixed plate, the bypass holes may be formed at any
position on the plate portion of the second scroll. Further, as the
bypass valve may be installed, overload may be effectively
solved.
[0074] The shape of the bypass valve is not limited to the
illustrated example.
[0075] FIG. 11 is a perspective view of a bypass valve according to
an embodiment. In FIG. 11, the bypass valve has a structure in
which the valve bodies 124c may be connected to an edge portion
124d. More specifically, the valve supporting portions 124a may be
coupled to the plate portion 143 of the second scroll 140, for
example, by bolts 106, and may be connected to each other by the
edge portion 124d. The two connection portions 124b may be
connected to a portion of the valve supporting portions 124a, and
the valve bodies 124c may be formed at ends of the connection
portions 124b.
[0076] According to this embodiment, the bypass valve may be fixed
by bolts used to connect the second scroll and the back pressure
plate to each other, without using an additional coupling device.
Accordingly, this may simplify the assembly processes.
[0077] FIG. 12 is a cross-sectional view showing a bypass valve
according to another embodiment. In FIG. 12, a valve installation
hole 152a may be formed in the groove portion 161, and a bypass
valve 220 may be installed in the valve installation hole 152a. The
bypass valve 220 may include a valve body 224 to open and close the
bypass hole 149 and a stem 222 formed on a rear surface of the
valve body 224. The stem 222 may be installed so as to be movable
up and down in the valve installation hole 152a. A coil spring 226
to press the valve body 224 downward when an external force is not
applied to the valve body 224 may be installed on an outer
circumferential part of the stem 222.
[0078] According to this embodiment, if the pressure inside the
intermediate pressure chamber becomes higher than the discharge
pressure, the bypass valve 220 may apply a force greater than an
elastic force of the coil spring 226 to the coil spring 226. As a
result, the bypass valve 220 may move upward. Accordingly, the
bypass hole may open, and refrigerant inside the intermediate
pressure chamber may be discharged to the discharge space.
[0079] According to another embodiment, the coil spring 226 may not
be provided. However, even if the coil spring 226 is not provided,
the pressure of the discharge space may be applied to an upper
surface of the valve body 224. Accordingly, in a case in which the
pressure of the intermediate pressure chamber is lower than the
pressure of the discharge space, the valve body 224 may cover the
bypass hole. If the coil spring 226 is provided, the open valve
body may move downward more rapidly, thus enhancing a response of
the valve.
[0080] FIG. 13 is a perspective view showing a bypass valve
according to yet another embodiment. In FIG. 13, a plate portion
243 including a discharge opening 245 at a central portion thereof
may be formed on an upper surface of a second scroll 240, and a
suction opening 244 may be formed on a side surface of the second
scroll 240. Bolt coupling holes 248 may be disposed near an edge of
the plate portion 243, and a central portion of the plate portion
243 may be concaved to form a concaved portion 243a.
[0081] A gasket 244 may be provided at a periphery of the discharge
opening 245. The gasket 244 may serve to prevent leakage of a
refrigerant from a space between the plate portion 243 and the back
pressure plate 150. A pair of protrusions 244a may be formed on an
inner circumference portion of the gasket 244. The protrusions 244a
may be coupled to pins 242 installed above the plate portion 243,
thereby guiding the gasket 244 to be positioned at a precise
position.
[0082] The bypass valve may be installed in the gasket 244, and may
include valve supporting portions 224a to insert the pins 242
thereinto, and a connection portion 224b that extends between the
valve supporting portions 224a. The connection portion 224b may
have an approximate circular shape, and the valve body 224c may be
formed on the connection portion 224b to open and close the bypass
holes.
[0083] According to this embodiment, if the back pressure plate and
the second scroll are coupled to each other through fitting the
bypass valve into the pins, the bypass valve may be coupled to the
back pressure plate or the second scroll. This may facilitate the
assembly process of the scroll compressor.
[0084] Embodiments disclosed herein provide a scroll compressor and
a method thereof.
[0085] Embodiments disclosed herein a scroll compressor that may
comprise a casing; a discharge cover fastened to the casing from
within, the discharge cover dividing an inner space of the casing
into a suction space and a discharge space; a main frame fastened
to the casing from within, the main frame formed spaced apart from
the discharge cover; a first or orbital scroll supported by the
main frame, the orbital scroll configured to perform an orbital
motion with respect to a rotational shaft of the orbital scroll in
operation; a second or fixed scroll forming a suction chamber, an
intermediate pressure chamber, and a discharge chamber together
with the orbital scroll, the fixed scroll formed to be movable with
respect to the orbital scroll and comprising a bypass hole that
communicates with the intermediate pressure chamber; a back
pressure chamber assembly coupled to an upper part of the fixed
scroll with a fastening means or fastener, the back pressure
chamber assembly being configured to press the fixed scroll toward
the orbital scroll by receiving part of an operation fluid from the
intermediate pressure chamber, and the back pressure chamber
assembly having a discharge path that communicates the discharge
chamber and the discharge space with each other; and a bypass valve
that opens and closes the bypass hole, where a bypass path by which
the bypass hole and the discharge path communicate with each other
is formed between the back pressure chamber assembly and the fixed
scroll.
[0086] Embodiments disclosed herein provide a scroll compressor
that may include a casing; a discharge cover fixed to inside of the
casing, and dividing the inside of the casing into a suction space
and a discharge space; a main frame spaced from the discharge
cover; a first or orbital scroll which performs an orbital motion
in a supported state on the main frame; a second or fixed scroll
installed to be movable up and down with respect to the orbital
scroll, forming a suction chamber, an intermediate pressure
chamber, and a discharge chamber together with the orbital scroll,
and having one or more bypass holes that communicate with the
intermediate pressure chamber; a back pressure chamber assembly
coupled to an upper part of the fixed scroll to restrict an upward
motion of the fixed scroll, configured to press the fixed scroll
toward the orbital scroll by introducing (e.g., accommodating,
receiving, etc.) part of an operation fluid inside the intermediate
pressure chamber, and having a discharge path to communicate the
discharge chamber and the discharge space with each other; and a
bypass valve to open and close the bypass hole. A bypass path to
communicate the bypass hole and the discharge path with each other
may be formed between the back pressure chamber assembly and the
fixed scroll.
[0087] The fixed scroll may be divided into a fixed wrap part and a
back pressure chamber part, and a bypass valve and a bypass path
may be disposed therebetween before the fixed wrap part and the
back pressure chamber part are fastened using a fastening device.
This may facilitate installation of the bypass valve, and may allow
the bypass hole to be formed at an arbitrary position.
[0088] The suction chamber, the intermediate pressure chamber, and
the discharge chamber may be some of a plurality of compression
chambers formed by the orbital scroll and the fixed scroll. More
specifically, the suction chamber may refer to a compression
chamber to which a refrigerant has been sucked to start a
compression operation. The discharge chamber, which may communicate
with a discharge opening, may refer to a compression chamber where
a discharge has just begun or is in the process. The intermediate
pressure chamber, which may be disposed between the suction chamber
and the discharge chamber, may refer to a compression chamber where
a compression operation is being processed or performed.
[0089] The bypass valve may be configured to be opened and closed
by a pressure difference between the intermediate pressure chamber
and the discharge space. The pressure of the discharge space may
mean an average pressure inside the discharge space, not a pressure
of a refrigerant discharged through the fixed scroll.
[0090] An open degree restricting means or restrictor that
restricts an open degree of the bypass valve may be provided. The
open degree restricting means may be formed on a lower surface of
the back pressure chamber assembly, and may be provided with an
additional retainer. The retainer may be formed to have a shape to
optimize an open shape of the bypass valve. The retainer may be
additionally provided. Alternatively, a lower surface of the back
pressure chamber assembly may be implemented as the retainer.
[0091] The bypass path may be defined by a groove portion concaved
from a lower surface of the back pressure chamber assembly and an
upper surface of the fixed scroll. Further, the bypass path may be
defined by a groove portion concaved from an upper surface of the
fixed scroll and a lower surface of the back pressure chamber
assembly. The bypass valve may be configured to open and close the
bypass hole while moving in the groove portion up and down. An
amount of the up-and-down motion of the bypass valve may be
restricted by an inner surface of the groove portion.
[0092] The bypass valve may include a valve body configured to
cover the bypass hole and a valve supporting portion or support
configured to fix the valve body between the fixed scroll and the
back pressure chamber assembly. A single valve supporting portion
may be provided with a plurality of valve bodies. For example, the
valve supporting portion may be formed to enclose the discharge
opening, and the valve body may extend inward from the valve
supporting portion in a radial direction. As another example, the
valve supporting portion may extend in a `V` shape.
[0093] The valve supporting portion may be fixed by a coupling
member that couples the back pressure assembly and the fixed scroll
to each other or by an additional coupling member. In this case,
the valve supporting portion may be fixed to the fixed scroll by,
for example, rivets.
[0094] A sealing means or seal to enclose the discharge path may be
provided between contact surfaces of the back pressure chamber
assembly and the fixed scroll.
[0095] The back pressure chamber assembly may include a back
pressure plate fixed to the fixed scroll below the discharge cover,
and provided with a space portion or space an upper part of which
is open, the space portion communicating with the intermediate
pressure chamber; and a floating plate movably coupled to the back
pressure plate so as to seal the space portion, and forming a back
pressure chamber.
[0096] The back pressure plate may include a supporting plate,
which may have a ring shape and may contact an upper surface of the
fixed scroll, a first ring-shaped wall formed to enclose an inner
space portion of the supporting plate, and a second ring-shaped
wall disposed on or at an outer circumferential part of the first
ring-shaped wall. A plurality of bolt coupling holes may be formed
at or in the supporting plate, and the fixed scroll and the back
pressure plate may be coupled to each other by, for exmaple, bolts
which pass through the bolt coupling holes.
[0097] The floating plate may have a ring shape. The floating plate
and the back pressure plate may be coupled to each other such that
an outer circumferential surface of the first ring-shaped wall
contacts an inner circumferential surface of the floating plate and
an inner circumferential surface of the second ring-shaped wall
contacts an outer circumferential surface of the floating plate.
The second ring-shaped wall may be positioned on an outer
circumferential surface of the supporting plate.
[0098] A diameter of the bypass hole may be formed to be smaller
than a thickness of a wrap of the fixed scroll.
[0099] Embodiments disclosed herein further provide a scroll
compressor that may include a casing divided into a suction space
and a discharge space; a first or orbital scroll configured to
perform an orbital motion in operation; a second or fixed scroll
which forms a suction chamber, an intermediate pressure chamber,
and a discharge chamber together with the orbital scroll; a bypass
hole and a bypass valve configured to discharge an operation fluid
to outside of the fixed scroll when pressure of the intermediate
pressure chamber is higher than a discharge pressure; a discharge
path that communicates with the discharge space, and a bypass path
forming member configured to introduce the discharged operation
fluid inside the intermediate pressure chamber to the discharge
path. The discharged operation fluid inside the intermediate
pressure chamber may flow between facing surfaces of the fixed
scroll and the bypass path forming member, to reach the discharge
path.
[0100] Embodiments disclosed herein may have at least the following
advantages.
[0101] First, the fixed scroll may be divided into a fixed wrap
part and a back pressure chamber part, and the bypass valve and the
bypass path may be disposed therebetween, before the fixed wrap
part and the back pressure chamber part are fastened using a
fastening device. This may facilitate installation of the bypass
valve.
[0102] Further, a position of the bypass hole may be arbitrarily
set, thereby minimizing occurrence of overload applied to the
scroll compressor due to change in an operating condition. Further,
even if the scroll compressor is overloaded at an early stage of
its operation, the overload may be rapidly removed using the bypass
holes and associated components.
[0103] Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
invention. The appearances of such phrases in various places in the
specification are not necessarily all referring to the same
embodiment. Further, when a particular feature, structure, or
characteristic is described in connection with any embodiment, it
is submitted that it is within the purview of one skilled in the
art to effect such feature, structure, or characteristic in
connection with other ones of the embodiments.
[0104] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, it should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, various
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangement within
the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
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