U.S. patent application number 16/261794 was filed with the patent office on 2019-08-08 for motor operated compressor.
This patent application is currently assigned to LG ELECTRONICS INC.. The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to Jongtae HER, Jinyong JANG, Honghee PARK, Byungkil YOO.
Application Number | 20190242384 16/261794 |
Document ID | / |
Family ID | 66846339 |
Filed Date | 2019-08-08 |
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United States Patent
Application |
20190242384 |
Kind Code |
A1 |
YOO; Byungkil ; et
al. |
August 8, 2019 |
MOTOR OPERATED COMPRESSOR
Abstract
An electric compressor includes a first scroll, a second scroll
engaged with the first scroll and configured to form a compression
chamber between portions of the second scroll and the first scroll
during orbiting motion of the second scroll relative to the first
scroll, and a frame fixed on an opposite side of the second scroll
from the first scroll. A back-pressure space is formed between the
frame and the second scroll, and pressure in the back-pressure
space pushes the second scroll toward the first scroll. A
back-pressure passage connects the compression chamber and the
back-pressure space, and a valve member is disposed in the
back-pressure passage and selectively blocks movement of a fluid
from the back-pressure space to the compression chamber.
Inventors: |
YOO; Byungkil; (Seoul,
KR) ; PARK; Honghee; (Seoul, KR) ; JANG;
Jinyong; (Seoul, KR) ; HER; Jongtae; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
66846339 |
Appl. No.: |
16/261794 |
Filed: |
January 30, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 23/008 20130101;
F04C 27/005 20130101; F04C 18/0215 20130101; F04C 29/124 20130101;
F04C 18/0261 20130101 |
International
Class: |
F04C 29/12 20060101
F04C029/12; F04C 18/02 20060101 F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 6, 2018 |
KR |
10-2018-0014800 |
Claims
1. An electric compressor comprising: a first scroll; a second
scroll engaged with the first scroll and supported relative to the
first scroll such that an orbiting motion of the second scroll
relative to the first scroll forms a compression chamber between
the second scroll and the first scroll; a frame fixed to a housing
of the electric compressor and positioned on an opposite side of
the second scroll from the first scroll with the second scroll
interposed between the first scroll and the frame, the frame
forming a back-pressure space between the frame and the second
scroll, the second scroll being supported in a direction toward the
first scroll by a pressure in the back-pressure space; a
back-pressure passage connecting the compression chamber and the
back-pressure space; and a valve member disposed in the
back-pressure passage and selectively blocking movement of a fluid
from the back-pressure space to the compression chamber.
2. The electric compressor of claim 1, wherein the back-pressure
passage includes a back-pressure hole, one end of the back-pressure
hole being in fluid communication with the compression chamber and
an opposite end of the back-pressure hole being in fluid
communication with the back-pressure space, and a valve
accommodation recess being in fluid communication with the
back-pressure hole, the valve accommodation recess accommodating
the valve member, and the valve member being configured as a check
valve slidably movable inside the valve accommodation recess
according to a pressure difference between the compression chamber
and the back-pressure space.
3. The electric compressor of claim 2, wherein the valve member
includes a valve portion configured to open the back-pressure
passage at a first position of the valve member and close the
back-pressure passage at a second position of the valve member.
4. The electric compressor of claim 3, wherein the valve portion
has a first side surface, a second side surface, and a
circumferential surface connecting the first side surface and the
second side surface, and a diameter of the first side surface is
greater than an inner diameter of the back-pressure hole and a
diameter of the second side surface is smaller than an inner
diameter of the valve accommodation recess.
5. The electric compressor of claim 4, further comprising: an
opening and closing surface formed on the first side surface of the
valve portion such that at least a portion thereof is flat and
formed with a diameter greater than the inner diameter of the
back-pressure hole to block the back-pressure hole at the second
position of the valve member; a support surface formed on the
second side surface of the valve portion and formed to contact a
side surface of the valve accommodation recess at the first
position of the valve member; and a communication recess formed to
a predetermined depth on the support surface, opened to the
circumferential surface of the valve portion, and at least
partially overlapping the back-pressure hole facing the second side
surface.
6. The electric compressor of claim 5, wherein the valve member
further comprises at least one guide portion configured to guide
the valve portion from the first position to the second position,
and the at least one guide portion extends in a radial direction
toward an inner circumferential surface of the valve accommodation
recess from the circumferential surface of the valve portion.
7. The electric compressor of claim 6, wherein the at least one
guide portion includes two guide portions protruding in a radial
direction from portions of the circumferential surface of the valve
portion, and the communication recess is opened to the
circumferential surface of the valve portion positioned between the
two guide portions.
8. The electric compressor of claim 7, wherein the communication
recess has at least two end portions opened to the circumferential
surface of the valve portion.
9. The electric compressor of claim 6, wherein the at least one
guide portion includes a plurality of guide portions, and
respective guide portions of the plurality of guide portions are
formed at equal intervals along a circumferential direction of the
circumferential surface of the valve portion.
10. The electric compressor of claim 6, wherein the at least one
guide portion is a single guide portion, and a subtended angle of
the single guide portion is greater than or equal to approximately
180.degree..
11. The electric compressor of claim 6, wherein the at least one
guide portion has a thickness approximately equal to or smaller
than a thickness of the valve portion.
12. The electric compressor of claim 6, wherein at least one guide
recess is formed on an inner circumferential surface of the valve
accommodation recess and a respective one of the at least one guide
portion is inserted into the at least one guide recess and
restrained by the at least one guide recess from movement in a
circumferential direction.
13. The electric compressor of claim 1, wherein an elastic member
is disposed on any one of opposite sides of the valve member in a
direction of movement of the valve member.
14. The electric compressor of claim 1, wherein the back-pressure
passage includes: a first back-pressure hole formed in the first
scroll and in fluid communication with the compression chamber; and
a second back-pressure hole formed in the frame and in fluid
communication with the back-pressure hole, wherein the first
back-pressure hole and the second back-pressure hole are in fluid
communication with each other; and a valve accommodation recess
accommodating the valve member is formed at least in part in at
least one of the first scroll or the frame.
15. The electric compressor of claim 1, wherein the back-pressure
passage is formed penetrating through the second scroll and in
fluid communication with the back-pressure space, a valve
accommodation recess is formed in a middle portion of the
back-pressure passage, a stopper member configured for limiting
movement of the valve member is inserted in and coupled to the
valve accommodation recess, and the stopper member includes a
back-pressure hole in fluid communication with the back-pressure
passage.
16. An electric compressor comprising: a frame; a first scroll
fixedly supported in the frame; a second scroll pivotably supported
relative to the frame and the first scroll and engaged with the
first scroll; a compression chamber formed between the first scroll
and the second scroll and configured to decrease in volume from an
outer portion of the compression chamber toward an inner portion of
the compression chamber upon relative movement between the first
scroll and the second scroll to compress a fluid contained within
the compression chamber; a back-pressure space formed between the
second scroll and the frame, wherein pressure within the
back-pressure space acts on the second scroll and supports the
second scroll toward the first scroll; a back-pressure flow path
connecting the compression chamber and the back-pressure space; a
valve accommodation recess formed in a middle portion of the
back-pressure flow path; and a check valve disposed in the valve
accommodation recess and configured to block the back-pressure flow
path when a pressure in the back-pressure space is higher than a
pressure in the compression chamber.
17. The electric compressor of claim 16, wherein the check valve
includes a valve portion, the valve portion formed to include a
diameter greater than an inner diameter of the back-pressure flow
path and smaller than an inner diameter of the valve accommodation
recess, at least a portion of one side surface of the valve portion
is formed substantially flat to selectively establish close contact
with one side of the valve accommodation recess and block the
back-pressure flow path in a first position of the valve portion,
and the other side surface of the valve portion includes a
communication recess configured to open the back-pressure flow path
when the other side surface of the valve portion establishes close
contact with the other side of the valve accommodation recess in a
second position of the valve portion.
18. The electric compressor of claim 17, wherein the check valve
further includes at least one guide portion in slidable contact
with an inner circumferential surface of the valve accommodation
recess, and the at least one guide portion protrudes from a
circumferential surface of the valve portion along a
circumferential direction of the valve portion.
19. An electric compressor comprising: a frame; a fixed scroll
supported in the frame; an orbiting scroll pivotably supported
relative to the frame and the fixed scroll, engaged with the fixed
scroll, and interposed between the fixed scroll and the frame; a
compression chamber including at least two variable volumes formed
between the fixed scroll and the orbiting scroll, wherein orbital
movement of the orbiting scroll relative to the fixed scroll causes
the variable volumes of the compression chamber to alternately
increase in volume to draw fluid into the compression chamber and
decrease in volume to compress the fluid contained within the
compression chamber and discharge the fluid; a back-pressure space
formed between the orbiting scroll and the frame, wherein pressure
of fluid within the back-pressure space acts on a first side of the
orbiting scroll opposite from a second side of the orbiting scroll
engaged with the fixed scroll, the pressure pushing the orbiting
scroll in a direction toward the fixed scroll; a back-pressure
passage connecting the compression chamber and the back-pressure
space; a valve accommodation recess formed in a portion of the
back-pressure passage; and a check valve disposed in the valve
accommodation recess and configured to move to a position in which
the check valve blocks the back-pressure passage when a pressure in
the back-pressure space is higher than a pressure in the
compression chamber.
20. The electric compressor of claim 19, wherein: the back-pressure
passage is formed as one of a combination of through holes formed
in the fixed scroll and the frame, or a single through hole formed
in the orbiting scroll.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Pursuant to 35 U.S.C. .sctn. 119(a), this application claims
the benefit of earlier filing date and right of priority to Korean
Application No. 10-2018-0014800, filed on Feb. 6, 2018, the
contents of which is incorporated by reference herein in its
entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present disclosure relates to a compressor and, more
particularly, to a motor-operated compressor driven by a motor.
Background of the Invention
[0003] Generally, compressors for compressing a refrigerant in
automotive air conditioning systems have been developed in various
forms. Recently, motor-operated compressors (or electric
compressors) driven by electricity using motors have been actively
developed as automotive parts tend to become electronic/electric
components.
[0004] Among several electric compressing schemes, a scroll
compressing scheme suitable for a high compression ratio operation
is largely applied. In the scroll type electric compressor, a motor
part configured as a rotary motor is installed in a closed casing,
a compressing part including a fixed scroll and an orbiting scroll
is installed on one side of the motor part, and the motor part and
the compressing part are connected by a rotary shaft and a
rotational force from the motor part is transferred to the
compressing part. The rotational force transferred to the
compressing part causes the orbiting scroll to pivot relative to
the fixed scroll to form a pair of two compression chambers each
including a suction chamber, an intermediate pressure chamber, and
a discharge chamber so that a refrigerant is sucked into both
compression chambers, and compressed and simultaneously
discharged.
[0005] The related art electric compressor as described above is
known to be based on a scheme in which oil is separated from the
refrigerant discharged from the compression chamber to a discharge
space, a portion of the separated oil is guided to a back-pressure
space provided on a rear surface of the orbiting scroll, and the
orbiting scroll is supported toward the fixed scroll by pressure of
the oil. This is disclosed in Related art 1 (Japanese Patent
Laid-Open Publication No. 2010-14108, publication date: 2010 Jan.
21) and Related art 2 (Korean Patent Laid-open Publication No.
10-2017-0139394, Publication date: 2017 Dec. 19).
[0006] Also, Related art 3 (Korean Patent Laid-Open Publication No.
10-2013-0041740, published on Apr. 25, 2013) discloses a technique
of forming a back-pressure hole at an orbiting scroll to bypass a
portion of a refrigerant compressed in the compression chamber to a
back-pressure space to support a rear surface of the orbiting
scroll.
[0007] Such a technique is well known in the art and may be
referred to as an intermediate pressure back pressure system.
[0008] However, in the case of the related art intermediate
pressure back pressure scheme, if pressure of an intermediate
pressure chamber is lower than pressure of a back-pressure space, a
refrigerant (or/and oil) of the back-pressure space may flow back
to the intermediate chamber through a back-pressure hole due to a
pressure difference and the refrigerant flowing back to the
intermediate pressure chamber forms a relatively high pressure in
the intermediate pressure chamber, causing an over-compression.
[0009] When the pressure in the intermediate pressure chamber is
lower than the pressure in the back-pressure space, the refrigerant
(or the oil) in the back-pressure space flows back to the
intermediate pressure chamber through the back-pressure hole by the
pressure difference, There is a problem that the refrigerant
flowing backward to the intermediate pressure chamber forms a high
pressure relative to the pressure of the refrigerant compressed in
the intermediate pressure chamber, causing excessive compression
loss.
[0010] In addition, in the related art intermediate pressure back
pressure system, the back-pressure space interworks with the
intermediate pressure chamber and thus is not uniformly maintained,
failing to stably support the orbiting scroll. As a result, a
behavior of the orbiting scroll becomes unstable to cause the
refrigerant in the compression chamber to leak.
SUMMARY OF THE INVENTION
[0011] Therefore, an aspect of the detailed description is to
provide an electric compressor in which a pressure of a compression
chamber and a pressure of a back-pressure space are uniformly
maintained in a scheme in which a portion of a refrigerant
compressed in an intermediate pressure chamber of a compression
chamber is induced to a back-pressure space to support an orbiting
scroll by the pressure of the back-pressure space.
[0012] Another aspect of the detailed description is to provide an
electric compressor in which a refrigerant and oil are restrained
from flowing back to an intermediate pressure chamber from a
back-pressure space due to a pressure difference between the
intermediate pressure chamber and the back-pressure space.
[0013] Another aspect of the detailed description is to provide an
electric compressor in which a refrigerant and oil are restrained
from flowing back to an intermediate pressure chamber from a
back-pressure space by selectively opening and closing a flow path
between the intermediate pressure chamber and the back-pressure
space.
[0014] Another aspect of the detailed description is to provide an
electric compressor in which a valve for selectively opening and
closing a flow path between the intermediate pressure chamber and
the back-pressure space is provided and the occurrence of abnormal
noise is suppressed during a process of opening and closing a
compression chamber and the back-pressure space.
[0015] Another aspect of the detailed description is to provide an
electric compressor in which a valve is uniformly moved during a
process of opening and closing a compression chamber and a
back-pressure space.
[0016] Another aspect of the detailed description is to provide an
electric compressor in which a valve for selectively opening and
closing a flow path between the intermediate pressure chamber and
the back-pressure space is provided and, here, the valve can be
easily assembled.
[0017] Another aspect of the detailed description is to provide an
electric compressor in which a compression chamber and a
back-pressure space may be connected at a shortest distance to
facilitate manufacturing of the electric compressor.
[0018] To achieve these and other advantages and in accordance with
the purpose of this specification, as embodied and broadly
described herein, there is provided an electric compressor in which
a back-pressure space is provided on a rear surface of an orbiting
scroll to form a back pressure in a direction toward a fixed
scroll, a passage connecting a compression chamber between the
fixed scroll and the orbiting scroll and the back-pressure space is
formed, and a valve is provided to open and close the passage.
[0019] The orbiting scroll may be supported by a frame coupled to
the fixed scroll, and the passage may penetrate through the fixed
scroll and the frame.
[0020] The passage may penetrate through the orbiting scroll.
[0021] The valve may be configured as a piston valve, and a
communication recess may be formed to be connected to an outer
circumferential surface of the valve and one side surface to open
the passage.
[0022] To achieve these and other advantages and in accordance with
the purpose of this specification, as embodied and broadly
described herein, an electric compressor includes: a first scroll;
a second scroll engaged with the first scroll to make an orbiting
motion to form a compression chamber with the first scroll; a frame
fixed in a radial direction on the opposite side of the first
scroll with the second scroll interposed therebetween, forming a
back-pressure space with the second scroll so that the second
scroll is supported in a direction toward the first scroll by
pressure of the back-pressure space; a back-pressure passage
connecting the compression chamber and the back-pressure space; and
a valve member provided at the back-pressure passage and blocking
movement of a fluid from the back-pressure space to the compression
chamber.
[0023] The back-pressure passage may include a back-pressure hole
in which one end communicates with the compression chamber and the
other end communicates with the back-pressure space and a valve
accommodation recess communicating with the back-pressure hole and
accommodating the valve member, and the valve member is configured
as a check valve slidably moving inside the valve accommodation
recess according to a pressure difference between the compression
chamber and the back-pressure space.
[0024] The valve member may include a valve portion opening the
back-pressure passage at a first position and closing the
back-pressure passage at a second position.
[0025] The valve portion may have a first side surface, a second
side surface, and a circumferential surface connecting the first
side surface and the second side surface, and a diameter of the
first side surface and a diameter of the second side surface may be
greater than an inner diameter of the back-pressure hole and
smaller than an inner diameter of the valve accommodation
recess.
[0026] The electric compressor may further include: an opening and
closing surface formed on the first side surface of the valve
portion such that at least a portion thereof is flat and formed to
have a diameter greater than the inner diameter of the
back-pressure hole to block the back-pressure hole at the second
position; a support surface formed on the second side surface of
the valve portion and formed to contact a side surface of the valve
accommodation recess; and a communication recess formed to a
predetermined depth on the support surface, opened to the
circumferential surface of the valve portion, and at least
partially overlapping a back-pressure hole facing the second side
surface.
[0027] The valve member may further include: at least one guide
portion guiding the valve portion from the first position to the
second position, and the at least one guide portion may extend in a
radial direction toward an inner circumferential surface of the
valve accommodation recess on the circumferential surface of the
valve portion.
[0028] The at least one guide portion may protrude in a radial
direction from a portion excluding at least a portion of the
circumferential surface of the valve portion, and the communication
recess may be opened to the circumferential surface of the valve
portion positioned between the at least one guide portion.
[0029] The communication recess may have at least two end portions
opened to the circumferential surface of the valve portion.
[0030] The guide portion may be provided in plurality, and the
plurality of guide portions may be formed at equal intervals along
a circumferential direction.
[0031] The at least one guide portion may be a single guide
portion, and a subtended angle of the guide portion may be greater
than or equal to approximately 180.degree.. The term
"approximately" when used throughout this specification and claims
refers to an amount, value, or dimension within normal machining
and/or assembly tolerances.
[0032] The at least one guide portion may have a thickness which is
approximately equal to or smaller than a thickness of the valve
portion.
[0033] A guide recess may be formed on an inner circumferential
surface of the valve accommodation recess so that the at least one
guide portion is inserted into the guide recess so as to be
restrained in a circumferential direction.
[0034] An elastic member may be further provided on any one of both
sides of the valve member in a movement direction.
[0035] The back-pressure passage may include: a first back-pressure
hole provided at the first scroll and communicating with the
compression chamber; and a second back-pressure hole provided at
the frame and communicating with the back-pressure hole, wherein
the first back-pressure hole and the second back-pressure hole
communicate with each other and a valve accommodation recess
accommodating the valve may be formed on a surface where the first
back-pressure hole is formed or a surface where the second
back-pressure hole is formed.
[0036] The back-pressure passage may be formed to penetrate through
the second scroll facing the back-pressure space, a valve
accommodation recess may be formed in the middle of the
back-pressure passage, a stopper member limiting movement of the
valve member may be inserted and coupled to the valve accommodation
recess, and the stopper member may have a back-pressure hole
forming the back-pressure passage.
[0037] To achieve these and other advantages and in accordance with
the purpose of this specification, as embodied and broadly
described herein, an electric compressor includes: a compression
chamber formed between a first scroll and a second scroll and
moving from an outer side to an inner side so as to be reduced in
volume thereof to compress a fluid; a back-pressure space formed
between the second scroll and a frame supporting the second scroll
and supporting the second scroll toward the first scroll; a
back-pressure flow path connecting the compression chamber and the
back-pressure space; a valve accommodation recess provided in the
middle of the back-pressure flow path; and a check valve provided
at the valve accommodation recess and blocking the back-pressure
flow path when a pressure of the back-pressure space is higher than
a pressure of the compression chamber.
[0038] The check valve may include a valve portion formed with a
diameter greater than an inner diameter of the back-pressure flow
path and smaller than an inner diameter of the valve accommodation
recess, at least a portion of one side surface of the valve portion
may be formed to be flat so as to be in close contact with one side
of the valve accommodation recess to block the back-pressure flow
path, and the other side surface of the valve portion may have a
communication recess to open the back-pressure flow path in a state
in which the other side surface of the valve portion is in close
contact with the other side of the valve accommodation recess.
[0039] The check valve may further include: at least one guide
portion in slidable contact with an inner circumferential surface
of the valve accommodation recess to guide the valve portion, and
the at least one guide portion may protrude from a circumferential
surface of the valve portion along a circumferential direction.
[0040] In the electric compressor according to the present
disclosure, a back-pressure passage is formed between the
compression chamber and the back-pressure space and a check valve
is provided in the middle of the back-pressure passage, whereby the
refrigerant and oil may be restrained from flowing back to the
compression chamber when a pressure of the compression chamber is
temporarily low such as when the compression is re-started.
[0041] Further, since the communication recess is formed on one
side surface of the check valve, a wide flow path area may be
secured. As a result, the refrigerant and oil may quickly move from
the intermediate pressure chamber to the back-pressure space,
effectively ensuring a back pressure.
[0042] Further, according to the present disclosure, since a flow
path between the compression chamber and the back-pressure space is
selectively opened and closed, pressure in the compression chamber
and pressure in the back-pressure space are restrained from
becoming unstable, thus stabilizing the behavior of the orbiting
scroll to uniformly compress the refrigerant.
[0043] Further, in the present disclosure, an elastic member is
added to one side of the check valve that opens and closes a flow
path between the compression chamber and the back-pressure space to
suppress or minimize the occurrence of abnormal noise during the
process of opening and closing the check valve.
[0044] Further, according to the present disclosure, the check
valve that opens and closes a flow path between the compression
chamber and the back-pressure space is guided by the guide
protrusion and the guide recess to make the behavior of the valve
uniform, whereby the position of the passage may be constant,
increasing reliability of the check valve.
[0045] Further, according to the present disclosure, since an
accommodation recess of the check valve for opening and closing a
flow path between the compression chamber and the back-pressure
space may be formed as part of the back-pressure passage, the check
valve may be easily assembled.
[0046] Further, in the present disclosure, since a passage
connecting the compression chamber and the back-pressure space is
formed at the orbiting scroll forming the back-pressure space, a
distance between the compression chamber and the back-pressure
space may be minimized, facilitating manufacturing of the electric
compressor.
[0047] Further scope of applicability of the present application
will become more apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the scope of
the invention will become apparent to those skilled in the art from
the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] 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 exemplary
embodiments and together with the description serve to explain the
principles of the invention.
[0049] In the drawings:
[0050] FIG. 1 is a cross-sectional view illustrating the inside of
an electric compressor according to the present disclosure;
[0051] FIG. 2 is a plan view illustrating a state in which a fixed
side wrap and an orbiting side wrap are engaged in a compression
mechanism part according to FIG. 1;
[0052] FIG. 3 is a cross-sectional view illustrating an example in
which a back-pressure hole is formed to penetrate through a fixed
scroll and a frame according to the present disclosure;
[0053] FIGS. 4A and 4B are front and rear perspective views of a
check valve according to the present disclosure, respectively;
[0054] FIGS. 5A and 5B are front and rear cross-sectional views
illustrating states in which a check valve is inserted into a valve
accommodation recess according to the present disclosure,
respectively;
[0055] FIGS. 6A to 8D illustrate other embodiments of a check valve
according to the present disclosure, in which FIGS. 6A and 6B
illustrate a case in which a single guide portion is provided,
FIGS. 7A and 7B illustrate a case in which two guide portions are
provided, and FIGS. 8A to 8D illustrate a communication recess;
[0056] FIGS. 9A and 9B illustrate an operation of a check valve
according to the present disclosure, in which FIG. 9A illustrates a
state in which an electric compressor normally operates and FIG. 9B
illustrates an operation when the electric compressor starts;
[0057] FIG. 10 is a perspective view illustrating another
embodiment of a check valve according to the present
disclosure;
[0058] FIGS. 11A and 11B are cross-sectional views illustrating an
example in which a check valve has an elastic member according to
the present disclosure;
[0059] FIGS. 12 and 13 are cross-sectional views illustrating other
embodiments of a check valve and a valve accommodation recess
according to the present disclosure; and
[0060] FIG. 14 is a cross-sectional view illustrating an example in
which a back-pressure hole is formed to penetrate through an
orbiting scroll.
DETAILED DESCRIPTION OF THE INVENTION
[0061] Description will now be given in detail of the exemplary
embodiments, with reference to the accompanying drawings. For the
sake of brief description with reference to the drawings, the same
or equivalent components will be provided with the same reference
numbers, and description thereof will not be repeated.
[0062] Hereinafter, an electric compressor according to an
embodiment of the present disclosure will be described in detail
with reference to the accompanying drawings.
[0063] FIG. 1 is a cross-sectional view illustrating the inside of
an electric compressor according to the present disclosure, and
FIG. 2 is a plan view illustrating a state in which a fixed side
wrap and an orbiting side wrap are engaged in a compression
mechanism part according to FIG. 1.
[0064] As illustrated FIGS. 1 and 2, a low-pressure type electric
scroll compressor (hereinafter, referred to as an "electric
compressor") according to the present embodiment includes a driving
motor 103, which is a motor part, and a compression mechanism part
105 compressing a refrigerant using a rotational force of the
driving motor 103.
[0065] The compressor casing 101 includes an intake port 111a to
which a suction pipe is connected and an exhaust port 121a to which
a discharge pipe is connected. A suction space S1 is formed at the
intake port 111a, and a discharge space S2 is formed at the exhaust
port 121a, respectively. The driving motor 103 is installed in the
suction space S1, and the compressor of the present embodiment is a
low-pressure compressor.
[0066] The compressor casing 101 includes a main housing 110 in
which the driving motor 103 is installed and a rear housing 120
coupled to an open rear end of the main housing 110. An internal
space of the main housing 110 forms the suction space S1 together
with one side of the compression mechanism part 105 and an internal
space of the rear housing 120 forms the discharge space S2 together
with the other side of the compression mechanism part 105.
[0067] The main housing 110 has a cylindrical portion 111 having a
cylindrical shape, a closed portion 112 integrally extends from a
front end of the cylindrical portion 111 and is closed, and an
opening 113 is formed at a rear end of the cylindrical portion
111.
[0068] Meanwhile, the driving motor 103 forming a motor part is
press-fit and coupled inside the main housing 110. The driving
motor 103 includes a stator 131 fixed inside the main housing 110
and a rotor 132 positioned inside the stator 131 and rotated by an
interaction with the stator 131.
[0069] The stator 131 is shrink-fit and fixed to an inner
circumferential surface of the main housing 110. A rotary shaft 133
is press-fit and coupled to an inner circumferential surface of the
rotor 132.
[0070] The rotary shaft 133 is coupled to the center of the rotor
132 and a rear end thereof facing the compression mechanism part
105 is cantilevered to the frame 140 and the fixed scroll 150 as
described later.
[0071] Meanwhile, in the scroll compressor according to the present
embodiment, the orbiting scroll coupled to the rotary shaft is
supported by the frame and is pivotally moved relative to the fixed
scroll, thereby forming the compression mechanism part.
[0072] As illustrated in FIGS. 1 and 2, the compression mechanism
part 105 includes a frame 140, a fixed scroll (hereinafter,
referred to as a "first scroll") 150 supported by the frame 140,
and an orbiting scroll (hereinafter referred to as a "second
scroll") 160 provided between the frame 140 and the first scroll
150 and making an orbiting motion.
[0073] The frame 140 is coupled to a front side opening 113 of the
main housing 110. The first scroll 150 is fixedly supported on a
rear surface of the frame 140, and the second scroll 160 is
pivotably supported on the rear surface of the frame 140 to make an
orbiting motion between the first scroll 150 and the frame 140. The
second scroll 160 is coupled in an off-centered manner to the
rotary shaft 133 coupled to the rotor 132 of the driving motor 103
and makes an orbiting motion relative to the first scroll 150,
forming a pair of two compression chambers V including a suction
chamber, an intermediate pressure chamber, and a discharge
chamber.
[0074] The frame 140 includes a disk plate portion 141 having a
disk shape and a frame side wall portion 142 protruding from a rear
side surface of the frame disk plate portion 141 toward the first
scroll 150 and allowing a side wall portion 152 of the first scroll
150 (to be described hereinafter) is coupled.
[0075] A frame thrust surface 143 is formed on an inner side of the
frame side wall portion 142. The second scroll 160 is mounted and
supported in an axial direction on the frame thrust surface 143. A
back-pressure space 144 is formed at the center of the frame thrust
surface 143 and filled with a portion of the refrigerant compressed
in the compression chamber V and oil to support the rear surface of
the second scroll 160. Accordingly, a pressure of the back-pressure
space 144 corresponds to an immediate pressure between a pressure
of the suction space S1 and a final pressure (i.e., discharge
space) of the compression chamber V. This will be described later
together with a check valve opening and closing the of compression
chamber and the back-pressure space.
[0076] A frame shaft hole 145 through which the rotary shaft 133
passes is formed in the middle of the back-pressure space 144 and a
first bearing (not shown) is provided on an inner circumferential
surface of the frame shaft hole 145. The first bearing may be
formed of a bush bearing, but in some cases, it may be a ball
bearing. Here, the bush bearing is less expensive than the ball
bearing, and thus, the bush bearing is advantageous in terms of
cos, and also, the bush bearing is easily assembled and reduced in
weight and noise.
[0077] The back-pressure space 144 may be sealed by a first sealing
member 191 provided on a thrust surface between the frame 140 and
the second scroll 160 and a second sealing member 192 disposed
between an inner circumferential surface of the frame 140 and an
outer circumferential surface of the rotary shaft 133. However, the
second sealing member 192 may be omitted in some cases.
[0078] Meanwhile, the first scroll 150 may be fixedly coupled to
the frame 140 or may be press-fit and fixed to the casing 110.
[0079] In the first scroll 150, a fixed scroll disk plate portion
(hereinafter, referred to as a `fixed side disk plate portion`) 151
is formed to have a substantially disk shape, and a fixed scroll
side wall portion (hereinafter, referred to as a `first side wall
portion`) 152 coupled to the side wall portion 142 of the frame 140
is formed at the edge of the fixed side disk plate portion 151. A
fixed side wrap 153 engaged with an orbiting side wrap 162 (to be
described later) to form the compression chamber V is formed on a
front side of the fixed side disk plate portion 151. The fixed side
wrap 153 will be described later together with the orbiting side
wrap 162. The term "substantially" when used throughout this
specification and claims refers to a shape, dimension, value, or
other characteristic that meets the description within normal
material, machining and/or assembly tolerances.
[0080] A suction flow path (not shown) is formed on one side of the
first side wall portion 152 so that the suction space S1 and a
suction chamber (not shown) communicate with each other, and a
discharge port 155 is formed at a central portion of the fixed side
disk plate portion 151 and communicates with a discharge chamber so
that the compressed refrigerant is discharged to the discharge
space S2. Only one discharge port 155 may be formed to communicate
with both a first compression chamber V1 and a second compression
chamber V2 (to be described later) or a first discharge port 155a
and a second discharge port 155b may be formed to communicate with
the first compression chamber V1 and the second compression chamber
V2, respectively.
[0081] The second scroll 160 may be provided between the frame 140
and the first scroll 150 and may be coupled to the rotary shaft 133
in an off-centered manner so as to be pivotable.
[0082] In the second scroll 160, an orbiting scroll disk plate
portion (hereinafter, referred to as an "orbiting side disk plate
portion") 161 is formed to have a substantially disk shape and an
orbiting side wrap 162 engaged with the fixed side wrap 153 to form
a compression chamber is formed on a rear side of the orbiting side
disk plate portion 161. The orbiting side wrap 162 may be formed in
an involute shape together with the fixed side wrap 153 or may be
formed in various other shapes.
[0083] The orbiting side wrap 162 may have a shape in which a
plurality of circular arcs having different diameters and starting
points are connected to each other, and the outermost curve may
have a substantially oval shape having a longer axis and a shorter
axis. This may also be the same with the fixed side wrap 153.
[0084] A rotary shaft coupling portion 163 may be formed in a
penetrating manner at a central portion of the orbiting side disk
plate portion 161. The rotary shaft coupling portion 163 may form
an inner end portion of the orbiting side wrap 162 and an eccentric
portion 133a of the rotary shaft 133 (to be described later) may be
rotatably inserted and coupled to the rotary shaft coupling portion
163. An outer circumferential portion of the rotary shaft coupling
portion 163 may be connected to the orbiting side wrap 162 to form
the compression chamber V together with the fixed side wrap 153
during a compressing process.
[0085] The rotary shaft coupling portion 163 is formed to have a
height that overlaps on the same plane as the orbiting side wrap
162 so that the eccentric portion 133a of the rotary shaft 133 may
be disposed at a height that overlaps on the same plane with the
orbiting side wrap 162. Accordingly, a repulsive force and a
compressive force of the refrigerant are applied to the same plane
with respect to the orbiting side disk plate portion so as to be
canceled out, and thus, tilting of the second scroll 160 due to the
action of the compressive force and the repulsive force may be
prevented.
[0086] The rotary shaft coupling portion 163 has a concave portion
163a which is engaged with a protrusion 153a of the fixed side wrap
153 (to be described later) at an outer circumferential portion
facing an inner end of the fixed side wrap 153, and an increased
portion 163b is formed on one side of the concave portion 163a and
is formed on an upstream side along a formation direction of the
compression chamber V, and a thickness of the increased portion
163b is increased from an inner circumferential portion to an outer
circumferential portion of the rotary shaft coupling portion
163.
[0087] An increased portion 163b is formed on one side of the
portion 163a along the forming direction of the compression chamber
V to increase the thickness from the inner circumferential portion
to the outer circumferential portion of the rotary shaft coupling
portion 163 on the upstream side. Thus, a compression path of the
first compression chamber V1 immediately before discharging is
lengthened, and as a result, a compression ratio of the first
compression chamber V1 may be increased to be close to a
compression ratio of the second compression chamber V2.
[0088] A circular arc compression surface 163c having a circular
arc shape is formed on the other side of the concave portion 163a.
A diameter of the circular arc compression surface 163c is
determined by a thickness of an inner end portion of the fixed side
wrap 153 (i.e., a thickness of a discharge end) and an orbiting
radius of the orbiting side wrap 162. Here, when the thickness of
the inner end portion of the fixed side wrap 153 is increased, the
diameter of the circular arc compression surface 163c is increased.
Accordingly, a thickness of the orbiting side wrap around the
circular arc compression surface 163c is also increased to ensure
durability, and since a compression path is lengthened, a
compression ratio of the second compression chamber V2 may also be
increased.
[0089] A protrusion 153a protruding toward an outer circumferential
portion of the rotary shaft coupling portion 163 is formed near an
inner end portion (suction end or start end) of the fixed side wrap
153 corresponding to the rotary shaft coupling portion 163, and a
contact portion 153b may protrude from the protrusion 153a so as to
be engaged with the concave portion 163a. That is, the inner end
portion of the fixed side wrap 153 may have a thickness greater
than those of other portions. As a result, wrap strength of the
inner end portion, which is subjected to the greatest compressive
force in the fixed side wrap 153, may be improved to improve
durability.
[0090] The compression chamber V is formed between the fixed side
disk plate portion 151 and the fixed side wrap 153 and between the
orbiting side wrap 162 and the orbiting side disk plate portion
161, and the suction chamber, the intermediate pressure chamber,
and the discharge chamber may be continuously formed according to a
movement direction of the wraps.
[0091] The compression chamber V may include the first compression
chamber V1 formed between an inner side surface of the fixed side
wrap 153 and an outer side surface of the orbiting side wrap 162
and a second compression chamber V2 formed between an outer side
surface of the fixed side wrap 153 and an inner side surface of the
orbiting side wrap 162. That is, the first compression chamber V1
is formed between two contact points P11 and P12 formed as the
inner side surface of the fixed side wrap 153 and the outer side
surface of the orbiting side wrap 162 are in contact with each
other, and the second compression chamber V2 is formed between two
contact points P21 and P22 formed as the outer side surface of the
fixed side wrap 153 and the inner side surface of the orbiting side
wrap 162.
[0092] Here, in the first compression chamber V1 immediately before
discharging, when an angle having a greater value among angles
formed by two lines connecting the center O of the eccentric
portion, i.e., the center O of the rotary shaft coupling portion,
and the two contact points P11 and P12 is a, a may be smaller than
360.degree. (.alpha.<360.degree.) at least immediately before
starting discharging and a distance l between normal vectors at the
two contact points P11 and P12 has a value greater than 0.
[0093] As a result, compared with a case where the first
compression chamber immediately before discharging includes a fixed
side wrap and an orbiting side wrap forming an involute curve, the
compression chamber has a smaller volume, and thus, both a
compression ratio of the first compression chamber V1 and a
compression ratio of the second compression chamber V2 may be
improved.
[0094] In the figure, reference numeral 137 denotes a balance
weight.
[0095] The scroll compressor according to the embodiment described
above operates as follows.
[0096] That is, when power is applied to the driving motor 103, the
rotary shaft 133 rotates together with the rotor 132 to transmit a
rotational force to the second scroll 160, and the second scroll
160 makes an orbiting motion by an anti-rotation mechanism, and
accordingly, the compression chamber V may be continuously moved
toward the center side, while being reduced in volume.
[0097] The refrigerant then flows into the suction space S1 through
the suction port 111a and the refrigerant introduced into the
suction space S1 passes through a flow path formed on an outer
circumferential surface of the stator 131 and an inner
circumferential surface of the main housing 110 or an air gap
between the stator 131 and the rotor 132 so as to be sucked to the
compression chamber V through the suction flow path 154.
[0098] Here, a portion of the refrigerant sucked into the suction
space S1 through the intake port 111a first comes into contact with
the closed portion 112, which is a front side surface of the main
housing 110, before passing through the driving motor 103.
Accordingly, the closed portion 112 is heat-exchanged with and
cooled by the cold suction refrigerant to cool an inverter module
(not shown) attached to the outer side surface of the main housing
110.
[0099] The refrigerant sucked into the compression chamber V
through the suction space S1 is compressed by the first scroll 150
and the second scroll 160 and is discharged to the discharge space
S2 through the discharge port 155. In the discharge space S2, the
refrigerant and oil are separated and the refrigerant is discharged
to a refrigerating cycle through the exhaust port 121a, while the
oil gathers at a lower portion of the discharge space S2.
[0100] As described above, in the process of compressing the
refrigerant in the compression chamber between the first scroll and
the second scroll, the second scroll as the orbiting scroll may be
pushed toward the frame due to pressure of the compression chamber.
In this case, a gap may be formed between the first scroll and the
second scroll to cause a leakage between the compression chambers.
This phenomenon may be suppressed by pressure of the back-pressure
space formed on the rear side of the second scroll, that is,
between the second scroll and the frame.
[0101] As described above, in the back-pressure space, a portion of
the refrigerant compressed in the middle of the compression
chamber, that is, in the intermediate pressure chamber, is supplied
to the back-pressure space through the back-pressure hole, and
thus, the pressure in the back-pressure space forms the
intermediate pressure. Therefore, the second scroll is pushed
toward the first scroll by the force of the pressure in the
back-pressure space, so that the second scroll may be prevented
from moving away from the first scroll. Here, the back-pressure
hole may be formed to penetrate through the first scroll and the
frame, or may be formed to penetrate through the second scroll.
FIG. 3 is a cross-sectional view illustrating an example in which
the back-pressure hole is formed to penetrate through the first
scroll and the frame.
[0102] As illustrated in FIG. 3, the back-pressure hole 170 may
include a first back-pressure hole 171 formed at the first scroll
150 and a second back-pressure hole 172 formed at the frame
140.
[0103] A first end 171a of the first back-pressure hole 171 is open
to communicate with the intermediate pressure chamber of the
compression chamber V and a second end 171b of the first
back-pressure hole 171 is open to a rear side surface (i.e., a
fixed surface in contact with the frame) of the fixed side disk
plate portion 151 (That is, a fixing surface in contact with the
frame).
[0104] A first end 172a of the second back-pressure hole 172 is
open to the front side surface (i.e., a fixed surface in contact
with the first scroll) of the frame side wall portion 142 so as to
communicate with the second end 171b of the first back-pressure
hole 171 and the second end 172b of the second back-pressure hole
172 is open to communicate with a side wall surface of the
back-pressure space 144. Accordingly, the first back-pressure hole
171 and the second back-pressure hole 172 communicate with each
other to connect the compression chamber V and the back-pressure
space 144.
[0105] When the compression chamber V and the back-pressure space
144 are connected by the back-pressure hole 170 including the first
back-pressure hole 171 and the second back-pressure hole 172 as
described above, the refrigerant having the intermediate pressure
compressed in the compression chamber A moves to the back-pressure
space 144 through the back-pressure hole 170 and a back pressure
formed by the intermediate pressure refrigerant which moves to the
back-pressure space 144 supports the second scroll 1600 in a
direction toward the first scroll 150.
[0106] However, the pressure in the compression chamber is varied
while the compressor operates, stops, and re-starts, and as the
pressure in the compression chamber is varied, pressure in the
back-pressure space 144 is also changed. For example, at an initial
stage of the operation of the compressor or during a saving
operation, the pressure in the compression chamber V is not
sufficiently increased so the pressure in the intermediate pressure
chamber is lower than the pressure in the back-pressure space 144,
but when the compressor reaches a normal operation or during a
power operation, the pressure in the compression chamber
(intermediate pressure chamber) V becomes higher than the pressure
in the back-pressure space 144, and this process is repeated. Here,
when the pressure in the compression chamber V is higher than the
pressure in the back-pressure space 144, the refrigerant (or/and
oil) in the compression chamber (intermediate pressure chamber)
moves to the back-pressure space 144 through the back-pressure hole
170, generating a normal back pressure, but when the pressure in
the compression chamber V is lower than the pressure in the
back-pressure space 144, the refrigerant (and/or oil) in the
back-pressure space 144 may flow back to the intermediate pressure
chamber through the back-pressure hole 170. In this case, the
pressure in the intermediate pressure chamber may be increased to
degrade compression efficiency due to over-compression.
[0107] In view of this, in this embodiment, a valve accommodation
recess 175 is formed in the middle of the back-pressure hole 170,
and a check valve 180 may be installed to selectively open and
close the back-pressure hole 170, while moving between a first
position P1 and a second position P2 according to a pressure
difference between the compression chamber (intermediate pressure
chamber) and the back-pressure space 144. Here, the first position
P1 is a position where the back-pressure passage 170 is open, and
the second position P2 is a position where the back-pressure
passage 170 is closed (blocked).
[0108] The valve accommodation recess 175 may be formed in the
middle of the first back-pressure hole 171 or the second
back-pressure hole 172, i.e., between the first ends 171a and 172a
and the second ends 171b and 172b of the first back-pressure hole
171 or the second back-pressure hole 172. Alternatively, in
consideration of processing or assembling, the valve accommodation
recess 175 may be formed at the second end 171b of the first
back-pressure hole 171 or the first end 172a of the second
back-pressure hole 172, or a half of the valve accommodation recess
175 may be formed at the second end 171b of the first back-pressure
hole 171 and another half of the valve accommodation recess 175 may
be formed at the first end 172a of the second back-pressure hole
172. Hereinafter, an example in which the valve accommodation
recess 175 is formed at the second end 171b of the first
back-pressure hole 171 will be described.
[0109] The valve accommodation recess 175 is formed as a
cylindrical recess having an inner diameter D2 larger than an inner
diameter D1 of the first back-pressure hole 171. Thus, a first
valve seat surface 175a may be formed at an end portion of the
valve accommodation recess 175 adjacent to the first scroll 180
such that an opening and closing surface 181a forming a first side
surface in a valve portion 181 of the check valve 180 (to be
described later) is detachably attached. The first valve seat
surface 175a may be formed flat or may be stepped so that a sealing
surface for increasing a sealing force with respect to the check
valve 180 encloses the first back-pressure hole 171.
[0110] Also, the other end of the valve accommodation recess 175 is
open and an inner diameter D1' of the second back-pressure hole 172
is formed to be equal to the inner diameter D1 of the first
back-pressure hole 171, and thus, a portion excluding the second
back-pressure hole 172 is blocked by the front side surface of the
frame 140. Accordingly, a second valve seat surface 175b may be
formed in the vicinity of the end of the second back-pressure hole
172 so that a support surface 181b forming a second side surface of
the valve portion 181 of the check valve 180 is detachably
attached. Like the first valve seat surface, the second valve seat
surface may also be flat or have a sealing surface.
[0111] Meanwhile, as described above, the check valve 180 may be
configured as a piston valve that moves between the first position
P1 and the second position P2 in accordance with a pressure
difference between the compression chamber V and the back-pressure
space 144 as a whole.
[0112] The check valve 180 may include the valve portion 181
substantially opening and closing the back-pressure hole 170 and a
guide portion 182 for guiding the valve portion 181 to reciprocate
stably.
[0113] The valve portion 181 may include a first side surface
(opening and closing surface) 181a, a second side surface (support
surface) 181b, and a circumferential surface connecting the first
side surface 181a and the second side surface 181b, and may have a
short circular bar shape or a disk plate or a disk shape having a
predetermined thickness.
[0114] A diameter D3 of the first side surface 181a and a diameter
D3' of the second side surface 181b may be larger than the inner
diameter D1 or D1' of the back-pressure hole 170 and smaller than
the inner diameter D2 of the valve accommodation recess 175.
Accordingly, the valve portion 181 communicates the back-pressure
hole 170 at the first position P1 and may block the back-pressure
hole 170 at the second position P2.
[0115] On the first side surface of the valve portion 181, an
opening and closing surface 181a for opening and closing the first
back-pressure hole 171 may be formed. The opening surface 181a may
be formed larger than the inner diameter D1 of the first
back-pressure hole 171 so as to block the first back-pressure hole
171 at the second position P2. The opening surface 181a may be
formed to be flat on the entire first side surface, or it may be
formed flat only at a central portion of the first side surface and
may not be formed at the edge thereof.
[0116] The second side surface of the valve portion 181 may have
the support surface 181b to be detachably attached to the second
valve seat surface 175b around the second back-pressure hole 172.
The support surface 181b may be formed flat to be in contact with a
side surface of the valve 175, i.e., the second valve seat surface
175b, at the first position P1.
[0117] At least one guide portion 182 may be formed. Of course, a
plurality of guide portions 182 may be advantageous in terms of
stability of the check valve 180. However, if the number of the
guide portions 182 is large, the speed of the check valve 180 may
be deteriorated due to friction resistance. Therefore, it is
necessary to appropriately design the number and a sectional area
of the guide portion 182 in consideration of friction
resistance.
[0118] For example, as illustrated in FIGS. 4A to 5B, three guide
portions 182 may be formed. In this case, the guide portions 182
may be formed at an interval of 120 degrees along the
circumferential direction.
[0119] Further, as illustrated in FIGS. 6A and 6B, only one guide
portion 182 may be formed. However, when one guide portion 182 is
provided, an included angle (a) on both sides forming the guide
portion 182 may be approximately 180.degree. or greater. If the
included angle (a) is less than 180.degree., an opening side angle
between both sides of the guide portion 182 is 180.degree. or
greater, and as a result, an outer circumferential surface of the
guide portion 182 is separated from the inner circumferential
surface of the valve accommodation recess 175 and it cannot serve
as a valve. Of course, in this case, although the opening side
angle between the both side surfaces of the guide portion 182 is
180.degree. or greater, if a depth of the opening side is shallow,
the opening and closing surface 181a may open and close the first
back-pressure hole 171. The check valve 180 may then serve as a
valve. Nevertheless, the valve portion 181 of the check valve 180
is not constant in its movement in the valve accommodation recess
175 is not uniform in behavior in the valve accommodation recess
175 but fluctuates, causing valve noise or failing to uniformly
opening and closing the back-pressure hole to lead to a degradation
of the reliability.
[0120] Also, as illustrated in FIGS. 7A and 7B, the guide portion
182 may be formed on both sides. In this case, the guide portions
182 may be formed at an equal interval by 180.degree. so as to be
balanced when the check valve 180 is moved.
[0121] Meanwhile, a communication recess 183 may be formed to be
recessed to a predetermined depth at a central portion of the
support surface 181b so that the second back-pressure hole 172 is
open even when the support surface 181b is in contact with the
second valve seat surface 175b. As a result, the area of the flow
path of the refrigerant and the oil moving from the intermediate
pressure chamber to the back-pressure space 144 may be secured to
be large, and the back pressure may be rapidly secured against the
orbiting scroll.
[0122] The communication recess 183 may be open to a
circumferential surface of the valve portion 181 and at least a
portion thereof may overlap the second back-pressure hole 172
facing the support surface 181b. The communication recess 183 may
have various shapes. For example, the communication recess 183 may
have a T shape as illustrated in FIG. 4B. In this case, three
opening ends 183a may be respectively open between the guide
portions 182 to form a kind of communication flow path.
[0123] Also, the communication recess 183 may be formed to be open
at a circumferential surface of one side of the valve portion 181
and extend to a central portion as illustrated in FIG. 8A, or may
be open at a circumferential surface of one side of the valve
portion 181, extend to a central portion, and increased from the
central portion so as to be larger than the second back-pressure
hole 172 as illustrated in FIG. 8B. Alternatively, the
communication recess 183 may be formed across both outer
circumferential surfaces of the valve portion 181 as illustrated in
FIG. 8C, or the entire second side surface 181b of the valve
portion 181 may be stepped so as to be utilized as the
communication recess 181 as illustrated in FIG. 8D. In addition, as
described above, the communication recess 183 may have any shape as
long as it is open at the circumferential surface of the valve
portion 181 and communicate with the second back-pressure hole
172.
[0124] Meanwhile, the check valve 180 may be formed of a material
which is light and lubricous such as plastic, considering that it
is a piston valve which is moved by a pressure difference.
[0125] Operational effects of the check valve 180 provided in the
back-pressure hole in the electric compressor according to the
present embodiment as described above are as follows.
[0126] That is, as illustrated in FIG. 9A, when the compressor
operates normally or the pressure in the intermediate pressure
chamber is higher than the pressure in the back-pressure space 144,
a portion of the refrigerant compressed in the intermediate
pressure chamber V moves toward the valve accommodation recess 175
through the first back-pressure hole 171. Then, the check valve 180
is pushed by the refrigerant flowing from the intermediate pressure
chamber toward the back-pressure space 144 through the first
back-pressure hole 171, and thus, the first back-pressure hole 171
is opened. The refrigerant moving from the first back-pressure
space 144 to the valve accommodation recess 175 moves to the second
back-pressure hole 172 through the communication recess 183 between
the support surfaces 181b formed on the second side surface of the
check valve 180, and the refrigerant is introduced to the
back-pressure space 144 to form a back pressure.
[0127] Meanwhile, as illustrated in FIG. 9B, when the compressor is
stopped or the pressure in the intermediate pressure chamber is
lower than the pressure in the back-pressure space 144, the
refrigerant in the back-pressure space 144 flows through the second
back-pressure hole 172 into the valve accommodation recess 175.
Then, the check valve 180 is pushed by the refrigerant flowing from
the back-pressure space 144 to the intermediate pressure chamber
through the second back-pressure hole 172, and is moved toward the
first back-pressure hole 171. Then, the opening surface 181a of the
check valve 180 is brought into close contact with the first valve
seat surface 175a of the valve accommodation recess 175 to block
the first back-pressure hole 171. Then, the refrigerant in the
back-pressure space 144 is prevented from flowing back to the
intermediate pressure chamber. Thereafter, when the pressure of the
compression chamber (intermediate pressure chamber) V increases to
a predetermined pressure, the check valve 180 is pushed again in
the direction toward the second back-pressure hole 172 to open the
back-pressure hole. This sequential process is repeated.
[0128] In this manner, even when the compressor is stopped or the
pressure in the intermediate pressure chamber is lowered, the
pressure when the compressor operates or the pressure of the
intermediate pressure chamber may be maintained to be higher than
the pressure of the back-pressure space, whereby the second scroll
may be restrained from being excessively separated from the first
scroll even at initial driving of the compressor. Accordingly, the
pressure of the compression chamber is quickly increased to the
discharge pressure, improving compressor efficiency.
[0129] In addition, even when the pressure of the intermediate
pressure chamber is low when the compressor starts to operate or at
an initial stage of operation, the refrigerant having a relatively
high pressure is prevented from flowing back to the intermediate
pressure chamber from the back-pressure space. Thus, pressure
pulsation at the intermediate pressure chamber may be suppressed to
make the compression process uniform, and over-compression loss
made as the pressure in the intermediate pressure chamber is
excessively increased may be prevented in advance.
[0130] In the above-described embodiment, the thicknesses of the
valve portion and the guide portion are equal. However, in some
cases, the thickness of the guide portion may be thinner than the
thickness of the valve portion. For example, as illustrated in FIG.
10, the thickness of the valve portion 181 is formed to be thicker
than the thickness of the guide portion 182 and a stepped surface
182a may be formed at a portion where the valve portion 181 and the
guide portion 182 are in contact with each other. In this case, the
thickness of the guide portion 182 is reduced as much, reducing the
area of the guide portion 182 in contact with the inner
circumferential surface of the valve accommodation recess 175 to
reduce friction resistance. Therefore, the check valve 180 may be
moved more quickly, so that even when the pressure in the
intermediate pressure chamber is slightly low at the time of
restarting the compressor, the check valve 180 may be opened
rapidly to quickly increase the pressure in the back-pressure space
144.
[0131] Meanwhile, in the embodiments described above, the check
valve is moved only by a pressure difference, but in some cases, an
elastic member may be provided on at least one of both sides of the
check valve in a movement direction.
[0132] For example, when an elastic member 186 is provided on the
first side surface of the check valve 180 as illustrated in FIG.
11A, the back-pressure hole 170 may be opened more quickly, and
when the elastic member 186 Is installed on the second side surface
of the check valve 180 as illustrated in FIG. 11B, the
back-pressure hole 170 may be closed more quickly. When the elastic
member 186 is installed on each of the first side surface 181a and
the second side surface 181b of the check valve 180, noise such as
impulsive noise that occurs during the process of opening and
closing the check valve 180 may be absorbed to reduce overall noise
due to the check valve 180.
[0133] Also, in the embodiments described above, the inner
circumferential surface of the valve accommodation recess 175 has a
circular shape and the guide portion 182 of the check valve 180 has
a circular arc shape so that the check valve 180 is rotatably
provided in the valve accommodation recess 175. However, the valve
accommodation recess 175 and the check valve 180 may be engaged in
the circumferential direction so that the check valve 180 may be
moved in a predetermined path along the valve accommodation recess
175.
[0134] For example, as illustrated in FIG. 12, a guide recess 175c
may be formed on ab inner circumferential surface of the valve
accommodation recess 175 so that the guide portion 182 of the check
valve 180 may be inserted thereinto. The guide recess 175c may be
formed along a length direction of the valve accommodation recess
175. Accordingly, since the guide portion 182 is inserted into the
guide recess 175c of the valve accommodation recess 175, the check
valve 180 is restrained in rotation in a circumferential direction
and reciprocates along the same path.
[0135] Alternatively, as illustrated in FIG. 13, a guide recess
182b may be formed on an outer circumferential surface of the guide
portion 182 and a guide protrusion 175d may be formed on ab inner
circumferential surface of the valve accommodation recess 175. A
guide protrusion 175d of the valve accommodation recess 175 may be
inserted into the guide recess 182b of the guide portion 182 to
restrict rotation of the check valve 180 in the circumferential
direction. Of course, the guide projection and the guide recess may
be formed at the guide portion and the valve accommodation recess,
respectively.
[0136] When the guide recess 175c or the guide protrusion 175d is
formed at the valve accommodation recess 175 in an axial direction
as described above, the check valve 180 does not rotate in the
circumferential direction, and thus, the behavior of the check
valve 180 may be further stabilized.
[0137] In addition, the opening end 183a of the communication
recess 183 provided at the check valve 180 may be formed at a
predetermined position, for example, at the lowermost position.
When the electric compressor is installed in a lateral direction,
if the oil in the compression chamber V is introduced into the
valve accommodation recess 175 through the first back-pressure hole
171 together with the refrigerant, although a portion of the oil is
present on the bottom side of the valve accommodation recess 175,
the oil may be easily moved toward the second back-pressure hole
172 through the communication recess 183, and thus, the pressure in
the back-pressure space 144 may be increased to a proper pressure
more quickly.
[0138] Meanwhile, another embodiment of the electric compressor
according to the present disclosure is as follows.
[0139] That is, in the above-described embodiments, the
back-pressure hole is formed to penetrate through the first scroll
and the frame, but the back-pressure hole may be formed to
penetrate through the orbiting side disk plate portion of the
second scroll. FIG. 14 is a cross-sectional view illustrating an
example in which the back-pressure hole is formed to penetrate
through the orbiting scroll according to the present
disclosure.
[0140] As illustrated in the figure, a first back-pressure hole 271
is formed in the intermediate pressure chamber V toward the
back-pressure space 144, and a valve accommodation recess 275 may
be formed to be enlarged at one end (the second end toward the
back-pressure space in the drawing) among both ends of the first
back-pressure hole 271.
[0141] A stopper member 276 having a second back-pressure hole 272
may be inserted and coupled to an opening end of the valve
accommodation recess 275. As a result, the check valve 180
reciprocates inside the valve accommodation recess 275. The stopper
member 276 may be press-fit to the valve accommodation recess 275,
may be engaged in a screw shape, or may be bonded using an adhesive
or welding.
[0142] The second back-pressure hole 272, which forms a
back-pressure passage together with the first back-pressure hole
271, may be formed at a position and have a size always
communicating with the communication recess 183 of the check valve
180 as in the embodiment described above, and the opening and
closing surface 181 of the check valve 180 is formed to be greater
than an inner diameter of the first back-pressure hole 271 to
opening and close the first back-pressure hole 271. Other basic
configuration and corresponding operational effects of the check
valve 180 and the back-pressure hole are similar to those of the
embodiments described above. However, the present embodiment may be
easily machined, compared with the embodiments described above.
That is, in the embodiments described above, the back-pressure hole
170 is formed to penetrate through the first scroll 150 and the
frame 140, and thus, a path of the back-pressure hole 170 is
lengthened. Thus, it is difficult to form the back-pressure hole
170, and since the first back-pressure hole 171 and the second
back-pressure hole 172 must be aligned accurately, high precision
may be required in manufacturing the electric compressor. However,
in the case of forming the back-pressure hole 270 at the disk plate
portion 161 of the second scroll 160 as in the present embodiment,
the length of the back-pressure hole 270 is short, and since the
back-pressure hole 270 is formed at the one member, it is
advantageous in manufacturing the electric compressor. Also, since
the length of the back-pressure hole 170 is short, pressure drop of
the refrigerant may be restrained as much, rapidly increasing the
back pressure of the back-pressure space 144.
[0143] The foregoing embodiments and advantages are merely
exemplary and are not to be considered as limiting the present
disclosure. The present teachings may be readily applied to other
types of apparatuses. This description is intended to be
illustrative, and not to limit the scope of the claims. Many
alternatives, modifications, and variations will be apparent to
those skilled in the art. The features, structures, methods, and
other characteristics of the exemplary embodiments described herein
may be combined in various ways to obtain additional and/or
alternative exemplary embodiments.
[0144] As the present features may be embodied in several forms
without departing from the characteristics thereof, it should also
be understood that the above-described embodiments are not limited
by any of the details of the foregoing description, unless
otherwise specified, but rather should be considered broadly within
its scope as defined in the appended claims, and therefore all
changes and modifications that fall within the metes and bounds of
the claims, or equivalents of such metes and bounds are therefore
intended to be embraced by the appended claims.
* * * * *