U.S. patent application number 13/628188 was filed with the patent office on 2013-03-28 for scroll compressor.
The applicant listed for this patent is Cheolhwan KIM, Hakyoung Kim, Byeongchul Lee, Jaesang Lee, Kangwook Lee. Invention is credited to Cheolhwan KIM, Hakyoung Kim, Byeongchul Lee, Jaesang Lee, Kangwook Lee.
Application Number | 20130078129 13/628188 |
Document ID | / |
Family ID | 47911492 |
Filed Date | 2013-03-28 |
United States Patent
Application |
20130078129 |
Kind Code |
A1 |
KIM; Cheolhwan ; et
al. |
March 28, 2013 |
SCROLL COMPRESSOR
Abstract
The present disclosure relates to a scroll compressor. According
to the present disclosure, in a shaft penetration scroll compressor
in which an eccentric portion of the rotation shaft is overlapped
with a orbiting wrap of the orbiting scroll in a radial direction,
a back pressure chamber formed at a rear surface of the orbiting
scroll may be eccentrically formed from the circular center around
a discharge port to correspond to the eccentric discharge port,
thereby effectively preventing tilting of the orbiting scroll due
to the eccentricity of a gas force generated while the discharge
port is eccentrically formed.
Inventors: |
KIM; Cheolhwan; (Seoul,
KR) ; Lee; Kangwook; (Seoul, KR) ; Lee;
Jaesang; (Seoul, KR) ; Kim; Hakyoung; (Seoul,
KR) ; Lee; Byeongchul; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KIM; Cheolhwan
Lee; Kangwook
Lee; Jaesang
Kim; Hakyoung
Lee; Byeongchul |
Seoul
Seoul
Seoul
Seoul
Seoul |
|
KR
KR
KR
KR
KR |
|
|
Family ID: |
47911492 |
Appl. No.: |
13/628188 |
Filed: |
September 27, 2012 |
Current U.S.
Class: |
418/55.2 ;
418/55.3 |
Current CPC
Class: |
F04C 27/005 20130101;
F04C 18/0269 20130101; F04C 23/008 20130101; F04C 18/0215
20130101 |
Class at
Publication: |
418/55.2 ;
418/55.3 |
International
Class: |
F04C 2/02 20060101
F04C002/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2011 |
KR |
10-2011-0098587 |
Sep 28, 2011 |
KR |
10-2011-0098597 |
Claims
1. A scroll compressor, comprising: a fixed scroll having a fixed
wrap; a orbiting scroll configured to have a orbiting wrap engaged
with the fixed wrap to form a first and a second compression
chamber at an inner surface and an outer surface thereof, and
perform a orbiting with respect to the fixed scroll; a frame
provided at an opposite side of the fixed scroll by interposing the
orbiting scroll to support the orbiting scroll; a rotation shaft
configured to have an eccentric portion at an end portion thereof,
and combined with the orbiting scroll such that the eccentric
portion is overlapped with the orbiting wrap in a radial direction;
and a driving unit configured to drive the rotation shaft, wherein
a back pressure chamber is formed between the orbiting scroll and
the frame to support the orbiting scroll in the direction of the
fixed scroll, and when a line connecting the center (Po) of the
compression chamber immediately prior to discharging compressed
refrigerant from the first compression chamber and the second
compression chamber to the geometric center (Oo) of the orbiting
scroll is referred to as a first reference line (L1), the back
pressure chamber is formed such that the geometric center (So) of
the back pressure chamber is located in a range of .+-.90.degree.
with respect to the first reference line (L1).
2. The scroll compressor of claim 1, wherein when a line
perpendicular to the first reference line (L1) passing through the
geometric center (Oo) of the orbiting scroll is referred to as a
second reference line (L2), the geometric center (So) of the back
pressure chamber is formed at the side at which the center (Po) of
the final compression chamber is located with respect to the second
reference line (L2).
3. The scroll compressor of claim 1, wherein the back pressure
chamber is formed between a plurality of sealing members disposed
to have a predetermined distance in a radial direction, and a
cross-sectional area of the back pressure chamber between the
plurality of sealing members is formed to be identical along a
radial direction.
4. The scroll compressor of claim 1, wherein the back pressure
chamber is formed between a plurality of sealing members disposed
to have a predetermined distance in a radial direction, and at
least one side of the sealing member among the plurality of sealing
members is formed in a non-circular shape.
5. The scroll compressor of claim 1, wherein the first compression
chamber is formed between two contact points (P1, P2) generated
when an inner surface of the fixed wrap and an outer surface of the
orbiting wrap are brought into contact with each other, and when an
angle having a greater value between angles made by two lines
connecting the center (O) of the eccentric portion to the two
contact points (P1, P2), respectively, is .alpha.,
.alpha.<360.degree. at least prior to starting discharge.
6. The scroll compressor of claim 5, wherein when a distance
between perpendiculars at the two contact points (P1, P2) is I,
I>0.
7. The scroll compressor of claim 1, wherein a rotation shaft
combining portion combined with the eccentric portion at an inner
portion thereof is formed at a central portion of the orbiting
scroll, and a protrusion portion is formed at an inner
circumferential surface of an inner end portion of the fixed wrap,
and a concave portion brought into contact with the protrusion
portion to form a compression chamber is formed at an outer
circumferential surface of the rear surface combining portion.
8. A scroll compressor, comprising: a fixed scroll having a fixed
wrap; a orbiting scroll configured to have a orbiting wrap engaged
with the fixed wrap to form a first and a second compression
chamber at an inner surface and an outer surface thereof, and
perform a orbiting with respect to the fixed scroll; a frame
provided at an opposite side of the fixed scroll by interposing the
orbiting scroll to support the orbiting scroll; a rotation shaft
configured to have an eccentric portion at an end portion thereof,
and combined with the orbiting scroll such that the eccentric
portion is overlapped with the orbiting wrap in a radial direction;
and a driving unit configured to drive the rotation shaft, wherein
a back pressure chamber is formed between the orbiting scroll and
the frame to support the orbiting scroll in the direction of the
fixed scroll, and the back pressure chamber is formed between a
plurality of sealing members disposed to have a predetermined
distance in a radial direction.
9. The scroll compressor of claim 8, wherein a cross-sectional area
of the back pressure chamber between the plurality of sealing
members is formed to be identical along a radial direction.
10. The scroll compressor of claim 8, wherein the back pressure
chamber is formed in a non-circular shape.
11. The scroll compressor of claim 10, wherein a cross-sectional
area of the back pressure chamber in a radial direction is formed
to be different along the radial direction.
12. The scroll compressor of claim 8, wherein at least one side of
the sealing member among the plurality of sealing members is formed
in a non-circular shape.
13. The scroll compressor of claim 8, wherein when a line
connecting the center (Po) of the compression chamber immediately
prior to discharging compressed refrigerant from the first
compression chamber and the second compression chamber to the
geometric center (Oo) of the orbiting scroll is referred to as a
first reference line (L1), the back pressure chamber is formed such
that the geometric center (So) of the back pressure chamber is
located in a range of .+-.90.degree. with respect to the first
reference line (L1).
14. The scroll compressor of claim 13, wherein when a line
perpendicular to the first reference line (L1) passing through the
geometric center (Oo) of the orbiting scroll is referred to as a
second reference line (L2), the geometric center (So) of the back
pressure chamber is formed at the side at which the center (Po) of
the final compression chamber is located with respect to the second
reference line (L2).
15. The scroll compressor of claim 8, wherein the first compression
chamber is formed between two contact points (P1, P2) generated
when an inner surface of the fixed wrap and an outer surface of the
orbiting wrap are brought into contact with each other, and when an
angle having a greater value between angles made by two lines
connecting the center (O) of the eccentric portion to the two
contact points (P1, P2), respectively, is .alpha.,
.alpha.<360.degree. at least prior to starting discharge.
16. The scroll compressor of claim 15, wherein when a distance
between perpendiculars at the two contact points (P1, P2) is I,
I>0.
17. The scroll compressor of claim 8, wherein a rotation shaft
combining portion combined with the eccentric portion at an inner
portion thereof is formed at a central portion of the orbiting
scroll, and a protrusion portion is formed at an inner
circumferential surface of an inner end portion of the fixed wrap,
and a concave portion brought into contact with the protrusion
portion to form a compression chamber is formed at an outer
circumferential surface of the rear surface combining portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to Korean
Application No. 10-2011-0098587, filed in Korea on Sep. 28, 2011
and Korean Application No. 10-2011-0098597, filed in Korea on Sep.
28, 2011, which is herein expressly incorporated by reference in
its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] A scroll compressor is disclosed herein.
[0004] 2. Description of the Related Art
[0005] Scroll compressor may include a fixed scroll having a fixed
wrap and a orbiting scroll having a orbiting wrap. The scroll
compressor provides a method of inhaling and compressing
refrigerant through a continuous volume change of the compression
chamber formed between the fixed wrap and the orbiting wrap while
the orbiting scroll performs a circulating movement on the fixed
scroll.
[0006] Furthermore, the scroll compressor continuously performs
inhalation, compression and discharge, and thus has excellent
characteristics in the aspect of vibration and noise generated
during its operational process compared to other types of
compressors.
[0007] In a scroll compressor, the behavior characteristic is
determined by its type of the fixed wrap and orbiting wrap. The
fixed wrap and orbiting wrap may have an arbitrary shape, but
typically have an involute curved shape that can be easily
processed. The involute curve denotes a curve corresponding to a
trajectory drawn by a cross section of thread when unloosing thread
wound around a base circle having an arbitrary radius. When using
such an involute curve, the capacity change rate is constant
because a thickness of the wrap is constant and thus the number of
turns should be increased to obtain a sufficient level of
compression ratio, but it may also increase the size of the
compressor.
[0008] On the other hand, the orbiting scroll is typically formed
with a disk shaped end plate and the orbiting wrap at the side of
the end plate. Furthermore, a boss portion is formed at a rear
surface on which the orbiting wrap is not formed and connected to a
rotation shaft for circulating the orbiting scroll. Such a shape
may form a orbiting wrap over a substantially overall area of the
end plate, thereby decreasing a diameter of the end plate portion
for obtaining the same compression ratio. However, on the contrary,
the operating point to which a repulsive force of refrigerant is
applied and the operating point to which a reaction force for
cancelling out the repulsive force is applied are separated from
each other in an axial direction, thereby causing a problem of
increasing vibration or noise while the orbiting scroll is tilted
during the operational process.
[0009] As a method for solving such problems, there has been
disclosed a so-called shaft penetration scroll compressor which is
a type that a position at which the rotation shaft and the orbiting
scroll are combined with each other is formed on the same surface
as the orbiting wrap. In such a type of compressor, the operating
point of a repulsive force and the operating point of the reaction
force are applied at the same position, thereby solving a problem
that the orbiting scroll is inclined.
[0010] However, in case of a shaft penetration scroll compressor as
described above, a discharge port 11 of the orbiting scroll 1 is
eccentrically formed with respect to the center (Oo) of the
orbiting scroll 1, and thus a back pressure chamber (S) may be
formed between a rear surface of the orbiting scroll 1 and an upper
frame 2 such that the center (Os) of the sealing members 31, 32
supporting the orbiting scroll 1 is disposed to be identical to the
center (Oo) of the orbiting scroll 1 though a gas force is
eccentrically exerted, and as a result there has been a problem of
causing tilting of the orbiting scroll 1 due to the eccentricity of
the gas force. Undescribed reference numeral 4 in the drawing
represents a fixed scroll, and reference numeral 5 represents an
oldham ring.
SUMMARY OF THE INVENTION
[0011] An object of the present disclosure is to provide a scroll
compressor capable of preventing tilting of the orbiting scroll due
to the eccentricity of a gas force in advance.
[0012] In order to accomplish the foregoing object, there is
provided a scroll compressor, including a fixed scroll having a
fixed wrap; a orbiting scroll configured to have a orbiting wrap
engaged with the fixed wrap to form a first and a second
compression chamber at an inner surface and an outer surface
thereof, and perform a orbiting with respect to the fixed scroll; a
frame provided at an opposite side of the fixed scroll by
interposing the orbiting scroll to support the orbiting scroll; a
rotation shaft configured to have an eccentric portion at an end
portion thereof, and combined with the orbiting scroll such that
the eccentric portion is overlapped with the orbiting wrap in a
radial direction; and a driving unit configured to drive the
rotation shaft, wherein a back pressure chamber is formed between
the orbiting scroll and the frame to support the orbiting scroll in
the direction of the fixed scroll, and when a line connecting the
center (Po) of the compression chamber immediately prior to
discharging compressed refrigerant from the first compression
chamber and the second compression chamber to the geometric center
(Oo) of the orbiting scroll is referred to as a first reference
line (L1), the back pressure chamber is formed such that the
geometric center (So) of the back pressure chamber is located in a
range of .+-.90.degree. with respect to the first reference line
(L1).
[0013] Furthermore, in order to accomplish the foregoing object,
there is provided a scroll compressor, including a fixed scroll
having a fixed wrap; a orbiting scroll configured to have a
orbiting wrap engaged with the fixed wrap to form a first and a
second compression chamber at an inner surface and an outer surface
thereof, and perform a orbiting with respect to the fixed scroll; a
frame provided at an opposite side of the fixed scroll by
interposing the orbiting scroll to support the orbiting scroll; a
rotation shaft configured to have an eccentric portion at an end
portion thereof, and combined with the orbiting scroll such that
the eccentric portion is overlapped with the orbiting wrap in a
radial direction; and a driving unit configured to drive the
rotation shaft, wherein a back pressure chamber is formed between
the orbiting scroll and the frame to support the orbiting scroll in
the direction of the fixed scroll, and the back pressure chamber is
formed between a plurality of sealing members disposed to have a
predetermined distance in a radial direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention.
[0015] In the drawings:
[0016] FIG. 1 is a cross-sectional view illustrating a compression
unit in a shaft penetration scroll compressor in the related
art;
[0017] FIG. 2 is a plan view illustrating a back pressure chamber
in a compression unit according to FIG. 1;
[0018] FIG. 3 is a cross-sectional view schematically illustrating
the internal structure of a scroll compressor according to an
embodiment of the present disclosure;
[0019] FIG. 4 is a partial cross-sectional view illustrating a
compression unit in the embodiment illustrated in FIG. 3;
[0020] FIG. 5 is an exploded perspective view illustrating a
compression unit illustrated in FIG. 4;
[0021] FIGS. 6A and 6B are a plan view illustrating a first and a
second compression chamber immediately subsequent to inhalation and
immediately prior to discharge in a scroll compressor having a
orbiting wrap and a fixed wrap with an involute shape;
[0022] FIGS. 7A and 7B are a plan view illustrating a type of
orbiting wrap in a scroll compressor having a orbiting wrap and a
fixed wrap with another involute shape;
[0023] FIG. 8 is a plan view illustrating a orbiting wrap and a
fixed wrap obtained by another envelope line;
[0024] FIG. 9 is an enlarged plan view illustrating a central
portion thereof in FIG. 8;
[0025] FIG. 10 is a plan view illustrating a configuration in which
the orbiting wrap is located prior to 150.degree. starting
discharge in the embodiment illustrated in FIG. 8;
[0026] FIG. 11 is a plan view illustrating a time point at which
discharge is started from the second compression chamber in the
embodiment illustrated in FIG. 8;
[0027] FIG. 12 is a cross-sectional view illustrating a compression
unit according to the embodiment illustrated in FIG. 3;
[0028] FIG. 13 is a plan view illustrating an embodiment of the
back pressure chamber in a compression unit according to FIG.
12;
[0029] FIG. 14 is a schematic view for explaining the location of a
back pressure chamber according to FIG. 13;
[0030] FIG. 15 is a plan view illustrating another embodiment of
the back pressure chamber in a compression unit according to FIG.
12; and
[0031] FIG. 16 is a schematic view for explaining the location of a
back pressure chamber according to FIG. 13.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Hereinafter, a scroll compressor according to the present
disclosure will be described in detail based on an embodiment
illustrated in the accompanying drawings.
[0033] Referring to FIG. 3, a scroll compressor according to the
present embodiment has a cylindrically shaped casing 110, and an
upper shell 112 and a lower shell 114 for covering an upper portion
and a lower portion of the casing, respectively. The upper shell
and lower shell may be bonded to the casing to form one confined
space together with the casing.
[0034] A discharge pipe 116 may be provided at an upper portion of
the upper shell 112. The discharge pipe 116 corresponds to a path
through which compressed refrigerant is discharged to the outside,
and an oil separator (not shown) for separating oil mixed with the
discharged refrigerant may be connected to the discharge pipe 116.
Furthermore, a suction pipe 118 is provided at a lateral surface of
the casing 110. As a path through which refrigerant to be
compressed flows, the suction pipe 118 is located at a boundary
surface between the casing 110 and the upper shell 112 in FIG. 3,
but the location may be set at discretion. Moreover, the lower
shell 114 may also function as an oil chamber for storing oil
supplied to operate the compressor in an efficient manner.
[0035] A motor 120 as a driving unit may be provided at a
substantially central portion of the inner portion of the casing
110. The motor 120 may include a stator 122 fixed to an inner
surface of the casing 110 and a rotor 124 located at an inner
portion of the stator 122 to be rotated by an interaction with the
stator 122. A rotation shaft 126 is combined with the center of the
rotor 124 and rotated together with the rotor 124.
[0036] An oil passage 126a may be formed at an central portion of
the rotation shaft 126 to be extended along a length direction of
the rotation shaft 126, and an oil pump 126b for supplying oil
stored in the lower shell 114 to the upper portion thereof may be
provided at a lower end portion of the rotation shaft 126. The oil
pump 126b may have a shape in which a spiral groove is formed or a
separate impeller is provided at an inner portion of the oil
passage, and a separate capacity type pump may be provided
therein.
[0037] An enlarged diameter portion 126c inserted into an inner
portion of the boss portion formed on the fixed scroll which will
be described later may be formed at an upper end portion of the
rotation shaft 126. The enlarged diameter portion may be formed to
have a diameter larger than the other portion thereof, and a pin
portion 126d forming an eccentric portion together with the
eccentric bearing 128 which will be described later may be formed
at an end portion of the enlarged diameter portion. The eccentric
bearing 128 for forming an eccentric portion together with the pin
portion 126d may be inserted into the pin portion 126d, and
referring to FIG. 5, the eccentric bearing 128 may be eccentrically
inserted with respect to the pin portion 126d, and a combining
portion for both may be asymmetrically formed in a substantially
"D" shape based on the center of the pin portion such that the
eccentric bearing 128 is not rotated with respect to the pin
portion 126d.
[0038] A fixed scroll 130 may be mounted on a boundary portion
between the casing 110 and upper shell 112. The fixed scroll 130
may be pushed and fixed between the casing 110 and the upper shell
112 in a shrink fit manner or combined together with the casing 110
and upper shell 112 by welding.
[0039] A boss portion 132 into which the foregoing rotation shaft
126 is inserted may be formed at a bottom surface of the fixed
scroll 130. A penetration hole through which the pin portion 126d
of the rotation shaft 126 passes may be formed at an upper side
surface (based on FIG. 3) of the boss portion 132 and thus the pin
portion 126d may be protruded in the upward direction of the end
plate portion 134 of the fixed scroll 130 therethrough.
[0040] A fixed wrap 136 engaged with the orbiting wrap which will
be described later to form a compression chamber may be formed at
an upper portion surface of the end plate portion 134, and a space
portion for accommodating the orbiting scroll 140 which will be
described later may be formed, and a lateral wall portion 138
adjoining an inner circumferential surface of the casing 110 may be
formed at an outer circumferential portion of the end plate portion
134. A orbiting scroll support portion 138a on which an outer
circumferential portion of the orbiting scroll 140 is placed may be
formed at an inner side of the upper end portion of the lateral
wall portion 138, and the height of the orbiting scroll support
portion 138a may be formed to have the same height as the fixed
wrap 136 or to have a height slightly less than that of the fixed
wrap, and thus an end portion of the orbiting wrap can be brought
into contact with a surface of the end plate portion of the fixed
scroll.
[0041] The orbiting scroll 140 may be provided at an upper portion
of the fixed scroll 130. The orbiting scroll 140 may be formed with
a substantially circular shaped end plate portion 142 and a
orbiting wrap 144 engaged with the fixed wrap 136. A substantially
circular shaped rotation shaft combining portion 146 rotatably
inserted and fixed to the eccentric bearing 128 may be formed at a
central portion of the end plate portion 142. An outer
circumferential portion of the rotation shaft combining portion 146
may be connected to the orbiting wrap to perform the role of
forming a compression chamber together with the fixed wrap during
the compression process. It will be described later.
[0042] On the other hand, the eccentric bearing 128 may be inserted
into the rotation shaft combining portion 146 and thus an end
portion of the rotation shaft 126 may be inserted through the end
plate portion of the fixed scroll, and the orbiting wrap, fixed
wrap and eccentric bearing 128 may be provided to be overlapped
with one another in the radial direction of the compressor. During
compression, a repulsive force of refrigerant may be applied to the
fixed wrap and orbiting wrap, and a compression force may be
applied between the rotation shaft support portion and eccentric
bearing as a reaction force thereto. As described above, when part
of the shaft is overlapped with the wrap in a radial direction
through the end plate portion, the repulsive force and compression
force of refrigerant may be applied to the same surface based on
the end plate, and thus they may be cancelled out by each other.
Due to this, it may be possible to prevent the inclination of the
orbiting scroll by the operation of the compression force and
repulsive force.
[0043] Furthermore, though not shown in the drawing, a discharge
hole may be formed on the end plate portion 142 and thus compressed
refrigerant may be discharged to an inner portion of the casing.
The location of the discharge hole may be set at discretion by
taking a required discharge pressure or the like into
consideration.
[0044] Furthermore, an oldham ring 150 for preventing the rotation
of the orbiting scroll may be provided at an upper side of the
orbiting scroll 140. The oldham ring 150 may include a
substantially circular shaped ring portion 152 inserted into a rear
surface of the orbiting scroll 140 and a pair of first key 154 and
second key 156 which are protruded on a lateral surface of the ring
portion 152. The first key 154 may be protruded farther than the
thickness of an outer circumferential side of the end plate portion
142 of the orbiting scroll 140, and inserted into an inner portion
of the first key groove 154a formed over an upper end of the
lateral wall portion 138 of the fixed scroll 130 and the orbiting
scroll support portion 138a. Moreover, the second keys 156 may be
combined with the second key grooves 156a, respectively, formed at
an outer circumferential portion of the end plate portion 142 of
the orbiting scroll 140 in the state of being inserted therein.
[0045] Here, the first key groove 154a may be formed to have a
vertical portion extended in the upward direction and a horizontal
portion extended in the left/right direction, and a lower side end
portion of the first key 154 may always maintain a state of being
inserted in the horizontal portion of the first key groove 154a,
but an outer side end portion of the first key 154 in the radial
direction may be formed to be released from the vertical portion of
the first key groove 154a during the circular movement of the
orbiting scroll. In other words, a coupling between the first key
groove 154a and the fixed scroll may be made in the vertical
direction, thereby reducing the diameter of the fixed scroll.
[0046] Specifically, a clearance as much as corresponding to a
circular radius should be secured between an end plate of the
orbiting scroll and an inner wall of the fixed scroll. If a key of
the oldham ring is combined with the fixed scroll in the radial
direction, then the length of a key groove formed on the fixed
scroll should be at least greater than the circular radius to
prevent the oldham ring from being released from the key groove
during the circular process, and it may be a cause of increasing
the size of the fixed scroll.
[0047] On the contrary, as in the above embodiment, if the key
groove is extended to a lower space between the end plate and the
orbiting wrap in the orbiting scroll, it may be possible to secure
a sufficient length of the key groove and reducing the size of the
fixed scroll.
[0048] Moreover, in the above embodiment, all keys are formed at a
lateral surface of the ring portion, and thus the height of the
compression unit in the axial direction can be reduced compared to
a case that keys are formed, respectively, in both lateral surfaces
thereof.
[0049] On the other hand, a lower frame 160 for rotatably
supporting a lower side of the rotation shaft 126 may be provided
at a lower portion of the casing 110, and the orbiting scroll and
an upper frame 170 for supporting the oldham ring 150 may be
provided, respectively, at an upper portion of the orbiting scroll.
A hole communicated with a discharge hole of the orbiting scroll
140 to discharge compressed refrigerant to the side of the upper
shell may be formed at the center of the upper frame 170.
[0050] FIGS. 6A and 6B are a plan view illustrating a compression
chamber immediately subsequent to inhalation and a compression
chamber immediately prior to discharge in a scroll compressor
having a orbiting wrap and a fixed wrap formed with an involute
curve, and having a configuration that part of the shaft penetrates
the end plate. FIG. 6A is a view illustrating a change of the first
compression chamber formed between an inner lateral surface of the
fixed wrap and an outer lateral surface of the orbiting wrap, and
FIG. 6B is a view illustrating a change of the second compression
chamber formed between an inner lateral surface of the orbiting
wrap and an outer lateral surface of the fixed wrap.
[0051] In the scroll compressor, the compression chamber may be
created between two contact points generated when the fixed wrap
and orbiting wrap are brought into contact with each other, and in
case of the fixed wrap and orbiting wrap with an involute curve,
two contact points defining one compression chamber as illustrated
in FIG. 4 may be located on a straight line. In other words, the
compression chamber may be disposed over 360.degree. with respect
to the center of the rotation shaft.
[0052] Considering a volume change of the first compression chamber
in FIG. 6A, the volume of the compression chamber immediately
subsequent to inhalation located at the outside may be gradually
reduced while moving to the central portion thereof by a circular
movement of the orbiting scroll, and thus has a minimum value when
reaching an outer circumferential portion of the rotation shaft
combining portion located at the center of the orbiting scroll. In
case of the fixed wrap and orbiting wrap with an involute curve,
the volume reduction rate may be linearly reduced as increasing the
rotation angle of the rotation shaft, and thus the compression
chamber should be moved closely to the center if possible, to
obtain a high compression ratio, but in case where the rotation
shaft exists at the center as described above, it can be moved only
to an outer circumferential portion of the rotation shaft. Due to
this, the compression ratio may be reduced, and the compression
ratio is about 2.13 in FIG. 6A.
[0053] On the other hand, the second compression chamber
illustrated in FIG. 6B may have a lower compression ratio compared
to the first compression chamber, and thus have a value of about
1.46. However, in case of the second compression chamber, when a
connecting portion between the rotation shaft combining portion (P)
and the orbiting wrap is formed with a circular arc shape as
illustrated in FIG. 7A, a compression path of the second
compression chamber may be lengthened, thereby increasing the
compression ratio up to a level of 3.0. In this case, the second
compression chamber may have a range of less than 360 degrees
immediately prior to discharge. However, such a method cannot be
applicable to the first compression chamber.
[0054] Accordingly, in case of the fixed wrap and orbiting wrap
with an involute shape, an intentional level of compression ratio
can be obtained in case of the second compression chamber, but it
may be impossible in case of the first compression chamber, and as
a result, in case that there is a remarkable difference of
compression ratio between the two compression chambers, it will
affect a bad effect on the operation of the compressor.
[0055] In order to solve the foregoing problem, the fixed wrap and
orbiting wrap may be formed to have another curve other than the
involute curve. Referring to FIGS. 8 and 9, when the center of the
rotation shaft combining portion 146 is "O", and two contact points
are "P1, P2", respectively, it is seen that an angle .alpha.
defined by two straight lines connecting the two contact points
(P1, P2) to the center (O) of the rotation shaft combining portion
is less than 360.degree., and also a distance "I" between
perpendicular vectors at each contact point has a value greater
than "0". Due to this, the first compression chamber immediately
prior to discharge may have a volume less than a case of the fixed
wrap and orbiting wrap formed with an involute curve, thereby
increasing the compression ratio. Furthermore, the orbiting wrap
and fixed wrap illustrated in FIG. 8 may have a configuration in
which the diameter and starting point thereof are connected to a
plurality of different circular arcs, and the outermost curve may
have a substantially oval shape having the major and minor
axes.
[0056] Furthermore, a protrusion portion 137 protruded to the side
of the rotation shaft combining portion 146 may be formed adjacent
to an inner side end portion of the fixed wrap, and a contact
portion 137a formed to be protruded from the protrusion portion may
be additionally formed on the protrusion portion 137. In other
words, the inner side end portion of the fixed wrap may be formed
to have a thickness greater than the other portion thereof. Due to
this, a strength of the inner side end portion of the wrap
receiving the highest compression force on the fixed wrap can be
enhanced, thereby enhancing the durability.
[0057] On the other hand, the thickness of the fixed wrap is
gradually decreased from the contact point (P1) located at an inner
side between the two contact points forming the first compression
chamber at a discharge start time point as illustrated in FIG. 9.
Specifically, a first decreasing portion 137b adjacent to the
contact point (P1) and a second decreasing portion 137c adjacent to
the first decreasing portion are formed, and a thickness reduction
rate at the first decreasing portion may be greater than that at
the second decreasing portion. Furthermore, the thickness of the
fixed wrap may be increased for a predetermined section subsequent
to the second decreasing portion.
[0058] Furthermore, when a distance between an inner surface of the
fixed wrap and the axial center (O') of the rotation shaft is DF,
the DF may be decreased after being increased as moving in a
counter clockwise direction (based on FIG. 9) from the P1, and the
section thereof is shown in FIG. 10. FIG. 10 is a plan view
illustrating the location of the orbiting wrap prior to 150.degree.
starting discharge, and the orbiting wrap may reach a configuration
illustrated in FIG. 8 when the rotation shaft is further rotated by
150.degree. from the configuration of FIG. 10. Referring to FIG.
10, the contact point is located at an upper side of the rotation
shaft combining portion 146, and the DF may be increased and then
decreased during the section between P1 of FIG. 8 and P1 of FIG.
10.
[0059] A concave portion 145 engaged with the protrusion portion
may be formed at the rotation shaft combining portion 146. A
lateral surface of the concave portion 145 may be brought into
contact with the contact portion 137a of the protrusion portion 137
to form a side contact point of the first compression chamber. When
a distance between the center of the rotation shaft combining
portion 146 and an outer circumferential portion of the rotation
shaft combining portion 146 is "Do", the "Do" may be increased and
then decreased during the section between P1 of FIG. 8 and P1 of
FIG. 10. Similarly, the thickness of the rotation shaft combining
portion 146 may be also increased and then decreased during the
section between P1 of FIG. 8 and P1 of FIG. 10.
[0060] Furthermore, a side wall of the concave portion 145 may
include a first increasing portion 145a in which the thickness
thereof is drastically increased in a relatively high rate and a
second increasing portion 145b connected to the first increasing
portion in which the thickness is increased in a relatively low
rate. They may correspond to the first decreasing portion and the
second decreasing portion, respectively. The first increasing
portion, first decreasing portion, second increasing portion, and
second decreasing portion are obtained as a result of bending the
envelope line toward the rotation shaft combining portion. Due to
them, an inner side contact point (P1) forming the first
compression chamber may be located at the first increasing portion
and second increasing portion, and as a result, the compression
ratio can be increased by decreasing the length of the first
compression chamber immediately prior to discharge.
[0061] The other side wall of the concave portion 145 may be formed
to have a circular arc shape. The diameter of the circular arc may
be determined by a wrap thickness of the end portion of the fixed
wrap and a circular radius of the orbiting wrap, and the diameter
of the circular arc may be increased as increasing the thickness of
the end portion of the fixed wrap. Due to this, the thickness of
the orbiting wrap around the circular arc may be also increased to
secure the durability, and the compression path may be lengthened
and thus have an advantage of increasing the compression ratio of
the second compression chamber as much as the lengthened path.
[0062] Here, a central portion of the concave portion 145 may form
part of the second compression chamber. FIG. 11 is a plan view
illustrating the location of the orbiting wrap when discharge is
started from the second compression chamber, and the second
compression chamber is located adjacent to a circular shaped side
wall of the concave portion in FIG. 11, and when the rotation shaft
is further rotated, an end portion of the second compression
chamber may pass through a central portion of the concave
portion.
[0063] On the other hand, in case of a shaft penetration scroll
compressor as described above, a gas force may be eccentrically
exerted because the discharge port is eccentrically formed with
respect to the center of the rotation shaft (or the circular center
of the orbiting scroll), thereby causing tilting of the orbiting
scroll due to the eccentricity of a gas force. Taking this into
account, according to the present embodiment, the back pressure
chamber provided at an upper surface of the orbiting scroll may be
eccentrically disposed around the center of the discharge port by
taking an eccentric level of the discharge port into consideration,
and thus the discharge port may compensate the eccentricity of a
gas force that can be eccentrically formed with respect to the
circular center of the orbiting scroll.
[0064] For example, as illustrated in FIGS. 12 and 13, a first
sealing member 181 and a second sealing member 182 may be provided
between an upper surface of the orbiting scroll 140 and a lower
surface of the upper frame 170 corresponding thereto to have a
predetermined distance in a radial direction to form the back
pressure chamber (S) around the discharge port 148.
[0065] To this end, a first sealing groove 149a and a second
sealing groove 149b may be formed on at least one side (an upper
surface of the orbiting scroll in the present embodiment) of an
upper surface of the orbiting scroll 140 and a lower surface of the
upper frame 170 to allow the first sealing member 181 and second
sealing member 182, respectively, to be inserted therein. The first
sealing groove 149a and second sealing groove 149b may be formed to
correspond to the first sealing member 181 and second sealing
member 182.
[0066] The first sealing groove 149a and second sealing groove 149b
may be formed in a ring shape, respectively, to allow the sealing
members 181, 182, respectively, to be inserted therein.
Accordingly, a cross-sectional area of the back pressure chamber
(S) formed by the first sealing member 181 and second sealing
member 182 may be formed to be identical along a radial
direction.
[0067] Furthermore, the back pressure chamber (S) may be preferably
formed such that a supporting force exerts in an opposite direction
to the gas force in an axial direction. In other words, as
illustrated in FIG. 14, when a line connecting the center (Po) of
the compression chamber immediately prior to discharge to the
geometric center (Oo) of the orbiting scroll is referred to as a
first reference line (L1), the back pressure chamber may be
preferably formed such that the geometric center (So) of the back
pressure chamber is located in a range of .+-.90.degree. with
respect to the first reference line (L1) while at the same time
located at the side at which the center (Po) of the final
compression chamber is located with respect to the second reference
line (L2).
[0068] According to a scroll compressor in accordance with the
foregoing embodiment, refrigerant at high pressure discharged
through the discharge port 148 of the orbiting scroll 140 may flow
into the back pressure chamber (S) to press and support the
orbiting scroll 140 in the direction of the fixed scroll with a
pressure of the back pressure chamber (S).
[0069] At this time, the back pressure chamber (S) may be
eccentrically formed from the geometric center (Oo) of the orbiting
scroll as much as the discharge port 148 is eccentrically located,
thereby preventing the orbiting scroll 140 from being tilted by the
eccentricity of a gas force in advance. As a result, in a shaft
penetration scroll compressor in which the rotation shaft 126 is
combined and overlapped with a orbiting wrap 144 of the orbiting
scroll 140 in a radial direction it may be possible to prevent
tilting of the orbiting scroll 140 due to the eccentricity of a gas
force generated while the discharge port 148 is eccentrically
formed with respect to the axial center of the rotation shaft 126,
thereby enhancing the compressor performance.
[0070] On the other hand, according to the foregoing embodiment,
the back pressure chamber may be formed to make a circular shape,
but the back pressure chamber may be also formed in an oval shape.
In other words, the back pressure chamber may be formed in an oval
shape having a long axis in the direction of the first reference
line. Even in this case, the back pressure chamber may have a shape
being moved in the direction of the discharge port compared to the
related art, thereby reducing tilting of the orbiting scroll due to
the eccentricity of a gas force to the extent of the movement.
[0071] On the other hand, in case of a shaft penetration scroll
compressor as described above, a gas force is eccentrically exerted
because the discharge port is eccentrically formed with respect to
the center of the rotation shaft (or the circular center of the
orbiting scroll), thereby causing tilting of the orbiting scroll
due to the eccentricity of a gas force. Taking this into account,
according to the present embodiment, the back pressure chamber
provided at an upper surface of the orbiting scroll may be
eccentrically disposed around the center of the discharge port by
taking an eccentric level of the discharge port into consideration,
and thus the discharge port may compensate the eccentricity of a
gas force that can be eccentrically formed with respect to the
circular center of the orbiting scroll.
[0072] For example, as illustrated in FIGS. 12 and 15, a first
sealing member 181 and a second sealing member 182 may be provided
between an upper surface of the orbiting scroll 140 and a lower
surface of the upper frame 170 corresponding thereto to have a
predetermined distance in a radial direction to form the back
pressure chamber (S) around the discharge port 148.
[0073] To this end, a first sealing groove 149a and a second
sealing groove 149b may be formed on at least one side (an upper
surface of the orbiting scroll in the present embodiment) of an
upper surface of the orbiting scroll 140 and a lower surface of the
upper frame 170 to allow the first sealing member 181 and second
sealing member 182, respectively, to be inserted therein. The first
sealing groove 149a and second sealing groove 149b may be formed to
correspond to the first sealing member 181 and second sealing
member 182.
[0074] For the first sealing member 181 and 182, a cross-sectional
area of the back pressure chamber (S) formed by the first sealing
member 181 and second sealing member 182 may be formed to be
identical along a radial direction, but according to circumstances,
a cross-sectional area of the back pressure chamber (S) may be also
formed to be different along a radial direction.
[0075] Either one side sealing member between the first sealing
member 181 and second sealing member 182 may be formed in a ring
shape whereas the other side sealing member may be formed in a
non-circular shape. Here, as illustrated in FIG. 16, when a line
connecting the center (Po) of the compression chamber immediately
prior to discharge to the geometric center (Oo) of the orbiting
scroll is referred to as a first reference line (L1), and a line
perpendicular to the first reference line (L1) passing through the
geometric center (Oo) of the orbiting scroll is referred to as a
second reference line (L2), the non-circular shaped sealing member
(the first sealing member and the second sealing member are formed
in a similar shape in FIG. 16) may be preferably formed to be
symmetric with respect to the first reference line (L1) and second
reference line (L2), respectively, thereby providing a uniform back
pressure to the orbiting scroll.
[0076] Furthermore, the back pressure chamber (S) may be formed
such that the geometric center (So) of the back pressure chamber is
identical to the geometric center (Oo) of the orbiting scroll, but
preferably formed such that a supporting force exerts in an
opposite direction to the gas force in an axial direction. In other
words, as illustrated in FIG. 16, the back pressure chamber may be
preferably formed such that the geometric center (So) of the back
pressure chamber is located in a range of .+-.90.degree. with
respect to the first reference line (L1) while at the same time
located at the side at which the center (Po) of the final
compression chamber is located with respect to the second reference
line (L2).
[0077] To this end, both the first sealing member 181 and second
sealing member 182 may be formed in a ring shape and thus
eccentrically disposed to the side of the discharge port 148, but
at least either one side sealing member between the first sealing
member 181 and second sealing member 182 (both sealing members are
formed in a non-circular shape in FIG. 15) may be formed in a
non-circular shape and thus the back pressure chamber (S) may be
eccentrically disposed to the side of the discharge port 148.
[0078] In this case, the non-circular sealing member may be formed
in a peanut shape with a wide discharge port and a narrow opposite
side thereof. As a result, the back pressure chamber can be
controlled to be located in a sufficiently eccentric manner without
disposing the first sealing member 181 and second sealing member
182 in an excessively eccentric manner.
[0079] According to a scroll compressor in accordance with the
foregoing embodiment, refrigerant at high pressure discharged to
the casing 110 through the discharge port 148 of the orbiting
scroll 140 may flow into the back pressure chamber (S) to press and
support the orbiting scroll 140 in the direction of the fixed
scroll with a pressure of the back pressure chamber (S).
[0080] At this time, the back pressure chamber (S) may be
eccentrically formed from the geometric center (Oo) of the orbiting
scroll as much as the discharge port 148 is eccentrically located,
thereby preventing the orbiting scroll 140 from being tilted by the
eccentricity of a gas force in advance. As a result, in a shaft
penetration scroll compressor in which the rotation shaft 126 is
combined and overlapped with a orbiting wrap 144 of the orbiting
scroll 140 in a radial direction, the discharge port 148 it may be
possible to prevent tilting of the orbiting scroll 140 due to the
eccentricity of a gas force generated while the discharge port 148
is eccentrically formed with respect to the axial center of the
rotation shaft 126, thereby enhancing the compressor
performance.
[0081] On the other hand, according to the foregoing embodiment, a
sealing member constituting the back pressure chamber may be a
non-circular shape, but both sides thereof may be formed to make a
substantially circular shape or both sides of the back pressure
chamber may be also formed to make an oval shape. In other words,
both sides of the sealing member may be formed in an oval shape
having a long axis in the direction of the first reference line,
respectively. Even in this case, the back pressure chamber may have
a shape being moved in the direction of the discharge port compared
to the related art, thereby reducing tilting of the orbiting scroll
due to the eccentricity of a gas force to the extent of the
movement.
* * * * *