U.S. patent application number 13/126153 was filed with the patent office on 2011-10-13 for linear compressor.
This patent application is currently assigned to LG ELECTRONICS INC.. Invention is credited to Won-Hyun Jung, Kyoung-Seok Kang, Hun-Sik Lee, Hyo-Jae Lee, Sang-Min Lee, Song-Oun Park, Ji-Hyun Shim.
Application Number | 20110250083 13/126153 |
Document ID | / |
Family ID | 42129460 |
Filed Date | 2011-10-13 |
United States Patent
Application |
20110250083 |
Kind Code |
A1 |
Park; Song-Oun ; et
al. |
October 13, 2011 |
LINEAR COMPRESSOR
Abstract
The present invention discloses a compressor including a
hermetic container into/from which refrigerant is sucked and
discharged, a compression unit provided in the hermetic container
and compressing the refrigerant, a motor unit provided in the
hermetic container to be connected to the compression unit and
driving the compression unit, and one or more irregular reflection
portions provided on an outer circumferential surface of the motor
unit. The irregular reflection portion repeatedly reflects and
dissipates noise and vibration in the compressor to improve the
noise reduction effect. In addition, the irregular reflection
portion increases the surface area of the motor unit to improve the
radiation effect, which results in high efficiency of the entire
compressor.
Inventors: |
Park; Song-Oun;
(Gyeongsangnam-do, KR) ; Lee; Sang-Min;
(Gyeongsangnam-do, KR) ; Jung; Won-Hyun;
(Gyeongsangnam-do, KR) ; Kang; Kyoung-Seok;
(Gyeongsangnam-do, KR) ; Lee; Hyo-Jae;
(Gyeongsangnam-do, KR) ; Lee; Hun-Sik;
(Gyeongsangnam-do, KR) ; Shim; Ji-Hyun;
(Gyeongsangnam-do, KR) |
Assignee: |
LG ELECTRONICS INC.
|
Family ID: |
42129460 |
Appl. No.: |
13/126153 |
Filed: |
October 28, 2009 |
PCT Filed: |
October 28, 2009 |
PCT NO: |
PCT/KR09/06261 |
371 Date: |
May 13, 2011 |
Current U.S.
Class: |
417/420 |
Current CPC
Class: |
H02K 5/18 20130101; F04B
39/0055 20130101; F04B 39/0027 20130101; F04B 35/045 20130101; F04B
39/121 20130101; H02K 1/16 20130101; G10K 11/16 20130101; F04B
35/04 20130101; F04B 39/122 20130101; H02K 5/24 20130101 |
Class at
Publication: |
417/420 |
International
Class: |
F04B 17/00 20060101
F04B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2008 |
KR |
10-2008-0105644 |
Claims
1. A compressor, comprising: a hermetic container into/from which
refrigerant is sucked and discharged; a compression unit provided
in the hermetic container and compressing the refrigerant; a motor
unit provided in the hermetic container to be connected to the
compression unit and driving the compression unit; and one or more
irregular reflection portions provided on an outer circumferential
surface of the motor unit.
2. The compressor of claim 1, wherein the motor unit comprises a
rotating shaft, a rotor having the rotating shaft fixed to a center
thereof, and a stator installed around the rotor and rotating the
rotor by a mutual electromagnetic force, wherein the irregular
reflection portion is provided on the stator.
3. The compressor of claim 2, wherein the compression unit
comprises a cylinder having a compression space in which the
refrigerant is compressed, and a piston reciprocated in the
compression space and compressing the refrigerant, and the motor
unit further comprises a connecting rod converting the rotational
motion of the rotating shaft into the linear reciprocating motion
of the piston, wherein the compressor is a reciprocating
compressor.
4. The compressor of claim 2, wherein the irregular reflection
portion is integrally formed with an outer circumferential surface
of the stator, or separately formed and attached thereto.
5. The compressor of claim 1, wherein the motor unit comprises an
inner stator, an outer stator fixed to the circumference of the
inner stator to maintain a certain interval, and a permanent magnet
maintaining a gap between the inner stator and the outer stator and
linearly reciprocated by a mutual electromagnetic force, wherein
the irregular reflection portion is provided on the outer
stator.
6. The compressor of claim 5, wherein the compression unit
comprises a fixed member having a compression space in which the
refrigerant is compressed, a movable member linearly reciprocated
in the fixed member and compressing the refrigerant, and one or
more springs installed to elastically support the movable member,
and the motor unit further comprises a connection member connecting
the permanent magnet to the movable member such that the permanent
magnet and the movable member are linearly reciprocated as one
body, wherein the compressor is a linear compressor.
7. The compressor of claim 5, wherein the irregular reflection
portion is integrally formed with an outer circumferential surface
of the outer stator, or separately formed and attached thereto.
8. The compressor of claim 1, wherein a spacing is defined between
the hermetic container and the irregular reflection portion, and
the irregular reflection portion comprises one or more of a groove
and a protrusion.
9. The compressor of claim 8, wherein the section of the groove or
the protrusion has a curved shape or a polygonal shape.
10. The compressor of claim 8, wherein the irregular reflection
portions are formed on the outer circumferential surface of the
motor unit to be symmetric.
11. The compressor of claim 8, wherein the grooves or the
protrusions of the irregular reflection portion are formed on the
outer circumferential surface of the motor unit at regular
intervals.
12. The compressor of claim 8, wherein the grooves or the
protrusions of the irregular reflection portion are formed on the
outer circumferential surface of the motor unit at irregular
intervals.
13. The compressor of claim 8, wherein the irregular reflection
portion is provided on a plane of the outer circumferential surface
of the motor unit.
14. The compressor of claim 8, wherein the compressor is vibrating
in the refrigerant-compressing direction and the opposite
direction, wherein the irregular reflection portion is provided on
one or more of the outer circumferential surface of the motor unit
which is parallel to the vibration direction of the compressor and
the outer circumferential surface of the motor unit which is
perpendicular to the vibration direction of the compressor.
15. The compressor of claim 14, wherein the section of the hermetic
container cut in the vibration direction of the compressor has a
circular or elliptical shape.
Description
TECHNICAL FIELD
[0001] The present invention relates to a compressor, and more
particularly, to a compressor which can reduce noise and vibration
generated during its operation.
BACKGROUND ART
[0002] In general, a compressor, which sucks refrigerant into its
hermetic container and compresses and discharges the refrigerant,
is used in refrigerators, air conditioners, etc. which employ a
freezing cycle. The freezing cycle includes a compressor sucking
and compressing low-temperature low-pressure refrigerant and
discharging high-temperature high-pressure refrigerant, a condenser
condensing the refrigerant discharged from the compressor, an
expansion device expanding the refrigerant condensed in the
condenser, and an evaporator evaporating the refrigerant expanded
in the expansion device by making the refrigerant exchange heat
with a medium such as the ambient air. The compressor, the
condenser, the expansion device and the evaporator are connected
through a series of refrigerant pipes to constitute a closed
circuit.
[0003] FIG. 1 is a sectional view of an example of a conventional
reciprocating compressor.
[0004] As illustrated in FIG. 1, the example of the conventional
reciprocating compressor includes a hermetic container 1 which is a
hermetic space into/from which refrigerant is sucked and
discharged, and a compression unit and a motor unit provided in the
hermetic container 1 and compressing and discharging the
refrigerant.
[0005] A suction pipe 2 and a discharge pipe 3 are installed
respectively on the hermetic container 1 in different directions.
The suction pipe 2 is connected to guide the refrigerant passing
through an evaporator to the inside of the hermetic container 1,
and the discharge pipe 3 is connected to guide the refrigerant
compressed in the compression unit to a condenser. A determined
spacing 4 is formed between the compression unit and the motor unit
in the hermetic container 1.
[0006] The compression unit includes a cylinder 11 defining a
compression space, a piston 12 linearly reciprocated in the
cylinder 11 and compressing refrigerant, a cylinder head 13 sealing
up the compression space and having a refrigerant discharge chamber
and a refrigerant suction chamber separated from each other, and a
valve assembly 14 interposed between the cylinder 11 and the
cylinder head 13 and controlling the flow of the refrigerant sucked
from the refrigerant suction chamber to the compression space or
the refrigerant discharged from the compression space to the
refrigerant discharge chamber. The refrigerant discharged to the
refrigerant discharge chamber is supplied to the condenser side
along the discharge pipe 3.
[0007] A suction muffler 15 is installed in the refrigerant suction
chamber of the cylinder head 13. The suction muffler 15 serves to
reduce noise of the refrigerant transferred to the inside of the
hermetic container 1 through the suction pipe 2. For this purpose,
the suction muffler 15 has a determined resonance space therein. A
discharge muffler 16 is further provided to be adjacent to the
cylinder 11 at an upper portion of the cylinder head 13. The
discharge muffler 16 reduces noise contained in the refrigerant
compressed by the piston 12 in the compression chamber of the
cylinder 11 and is integrally formed with a top surface of the
cylinder head 13.
[0008] Additionally, a loop pipe 17 is connected to the discharge
muffler 16. The loop pipe 17 serves to guide high-temperature
high-pressure refrigerant compressed in the cylinder 11 to be
discharged to the outside of the compressor. Moreover, the loop
pipe 17 is bent a few times to reduce vibration when the
refrigerant flows inside.
[0009] The motor unit includes a stator 21 producing a magnetic
field, a rotor 22 rotated to electromagnetically interact with the
stator 21, and a rotating shaft 23 press-fit into the center of the
rotor 22 and rotated with the rotor 22. In order to supply power of
the motor unit to the compression unit, a connecting rod 24
linearly reciprocating the piston 12 by converting the rotational
motion of the rotating shaft 23 into the linear motion is installed
at a bottom end portion of the rotating shaft 23.
[0010] In the conventional hermetic compressor so constructed, when
electricity is applied to the motor unit, it is applied to a coil
of the stator 21, thereby producing a magnetic field. The rotor 22
is rotated with the rotating shaft 23 by the magnetic field. Here,
the connecting rod 24 connected between the rotating shaft 23 and
the piston 12 converts the rotational force of the rotating shaft
23 into the linear reciprocating motion of the piston 12.
Accordingly, the piston 12 is linearly reciprocated in the cylinder
11 such that a pressure difference exists between the inside and
the outside of the compression space of the cylinder 11. The
refrigerant passing through the evaporator is guided to the inside
of the hermetic container 1 along the suction pipe 2 by the
pressure difference. The refrigerant guided to the inside of the
hermetic container 1 is introduced into the suction muffler 15.
After its noise is reduced, the refrigerant is guided to the inside
of the refrigerant suction chamber of the cylinder head 13, sucked
into the compression space, compressed into a high-temperature
high-pressure state, passed through the refrigerant discharge
chamber, and moved to the condenser along the discharge pipe 3. The
refrigerant completing the compression cycle along the suction pipe
2 is moved along the discharge pipe 3.
[0011] Vibration/noise is generated in X and Y directions by the
components of the compression cycle.
[0012] FIG. 2 is a front view of a stator applied to the example of
the conventional reciprocating compressor.
[0013] As illustrated in FIGS. 1 and 2, the conventional stator 21
is formed at the outermost portion of the motor unit explained
above. Here, the outer shape of the stator 21 is a rounded
quadrangle. More specifically, each edge of the quadrangle has a
smooth slope. A circular hollow portion 21a is provided in the
center of the stator 21, and slots 21b are formed radially from the
hollow portion 21a of the stator 21. A coil is wound through the
slots 21b. As described above, when the coil receives power from
the outside, the stator 21 becomes magnetic.
[0014] Each face of the stator 21 includes a plane portion 21c and
is curved in the portions other than the plane portion 21c. If
vibration generated during the operation of the compressor collides
against an inner circumferential surface of the hermetic container
1, it is reflected to the plane portion 21c. Then, the vibration is
reflected by the plane portion 21c to the inner circumferential
surface of the hermetic container 1, thereby generating noise. In
more detail, vibration and noise generated in the hermetic
container 1 collide against the inner circumferential surface of
the hermetic container 1, and thus are reflected to the components.
The vibration and noise reflected to the components are transferred
through the spacing 4 of the hermetic container 1 such that the
hermetic container 1 is excited to cause larger noise to the
outside. That is, noise generated in the hermetic container 1 is
successively reflected by the components, and thus transferred to
the outside. Particularly, the reciprocating compressor is excited
in Y direction of the hermetic container 1 in which the piston 12
is linearly reciprocated, thereby generating a lot of
noise/vibration/frequency/sound wave in Y direction. The noise or
the like is increased in the hermetic container 1 because it is
successively reflected between the inner circumferential surface of
the hermetic container 1 and the plane portion 21c of the stator
21.
[0015] In the conventional compressor, noise is generated due to
the operation of the compression unit and the motor unit, the
suction of refrigerant, the opening and closing of a valve, and the
friction of the respective components, etc., transferred through
the spacing of the hermetic container vibrating the hermetic
container, and then transferred to the outside of the hermetic
container. In addition, noise is generated in the hermetic
container by the vibration. As almost every component of the
compressor is made of a metal material which does not absorb but
reflect noise, they excite and increase noise rather than dissipate
it. Particularly, noise is increased because it is reflected
between the hermetic container and the plane portion of the stator
adjacent thereto. It is necessary to conduct the study for reducing
noise.
DISCLOSURE
Technical Problem
[0016] The present invention has been made in an effort to solve
the above-described problems of the prior art, and an object of the
present invention is to provide a compressor which can repeatedly
irregularly reflect and dissipate noise and vibration therein.
[0017] Another object of the present invention is to provide a
compressor which can dissipate vibration and noise therein and
improve radiation efficiency of a motor unit.
Technical Solution
[0018] According to an aspect of the present invention for
achieving the above objects, there is provided a compressor,
including: a hermetic container into/from which refrigerant is
sucked and discharged; a compression unit provided in the hermetic
container and compressing the refrigerant; a motor unit provided in
the hermetic container to be connected to the compression unit and
driving the compression unit; and one or more irregular reflection
portions provided on an outer circumferential surface of the motor
unit. In addition, the motor unit includes a rotating shaft, a
rotor having the rotating shaft fixed to a center thereof, and a
stator installed around the rotor and rotating the rotor by a
mutual electromagnetic force, wherein the irregular reflection
portion is provided on the stator.
[0019] Moreover, the compression unit includes a cylinder having a
compression space in which the refrigerant is compressed, and a
piston reciprocated in the compression space and compressing the
refrigerant, and the motor unit further includes a connecting rod
converting the rotational motion of the rotating shaft into the
linear reciprocating motion of the piston, wherein the compressor
is a reciprocating compressor.
[0020] Further, the irregular reflection portion is integrally
formed with an outer circumferential surface of the stator, or
separately formed and attached thereto.
[0021] Furthermore, the motor unit includes an inner stator, an
outer stator fixed to the circumference of the inner stator to
maintain a certain interval, and a permanent magnet maintaining a
gap between the inner stator and the outer stator and linearly
reciprocated by a mutual electromagnetic force, wherein the
irregular reflection portion is provided on the outer stator.
[0022] Still furthermore, the compression unit includes a fixed
member having a compression space in which the refrigerant is
compressed, a movable member linearly reciprocated in the fixed
member and compressing the refrigerant, and one or more springs
installed to elastically support the movable member, and the motor
unit further includes a connection member connecting the permanent
magnet to the movable member such that the permanent magnet and the
movable member are linearly reciprocated as one body, wherein the
compressor is a linear compressor.
[0023] Still furthermore, the irregular reflection portion is
integrally formed with an outer circumferential surface of the
outer stator, or separately formed and attached thereto.
[0024] Still furthermore, a spacing is defined between the hermetic
container and the irregular reflection portion, and the irregular
reflection portion includes one or more of a groove and a
protrusion.
[0025] Still furthermore, the section of the groove or the
protrusion has a curved shape or a polygonal shape.
[0026] Still furthermore, the irregular reflection portions are
formed on the outer circumferential surface of the motor unit to be
symmetric.
[0027] Still furthermore, the grooves or the protrusions of the
irregular reflection portion are formed on the outer
circumferential surface of the motor unit at regular intervals.
[0028] Still furthermore, the grooves or the protrusions of the
irregular reflection portion are formed on the outer
circumferential surface of the motor unit at irregular
intervals.
[0029] Still furthermore, the irregular reflection portion is
provided on a plane of the outer circumferential surface of the
motor unit.
[0030] Still furthermore, the compressor is vibrating in the
refrigerant-compressing direction and the opposite direction,
wherein the irregular reflection portion is provided on one or more
of the outer circumferential surface of the motor unit which is
parallel to the vibration direction of the compressor and the outer
circumferential surface of the motor unit which is perpendicular to
the vibration direction of the compressor.
[0031] Still furthermore, the section of the hermetic container cut
in the vibration direction of the compressor has a circular or
elliptical shape.
Advantageous Effects
[0032] In the compressor according to the present invention, the
irregular reflection portion is formed adjacent to the hermetic
container. Although noise collides against the inside of the
hermetic container and is incident on the irregular reflection
portion, the irregular reflection portion irregularly reflects and
dissipates the noise, thereby reducing noise.
[0033] Moreover, in the compressor according to the present
invention, the irregular reflection portion such as the protrusion
and the groove which increases the surface area is formed on the
circumference of the motor unit adjacent to the hermetic container.
The irregular reflection portion dissipates noise and radiates heat
generated in the motor unit, thereby improving efficiency of the
entire compressor.
DESCRIPTION OF DRAWINGS
[0034] FIG. 1 is a sectional view of an example of a conventional
reciprocating compressor;
[0035] FIG. 2 is a front view of a stator applied to the example of
the conventional reciprocating compressor;
[0036] FIG. 3 is a sectional view of an embodiment of a
reciprocating compressor according to the present invention;
[0037] FIGS. 4 and 5 are a front view and a side view of a first
embodiment of a stator applied to the embodiment of the
reciprocating compressor according to the present invention;
[0038] FIG. 6 is a graph of noise levels by X-direction frequencies
in the conventional reciprocating compressor and the reciprocating
compressor of the present invention, respectively;
[0039] FIG. 7 is a graph of noise levels by Y-direction frequencies
in the conventional reciprocating compressor and the reciprocating
compressor of the present invention, respectively;
[0040] FIG. 8 is a graph of noise changes in 400 Hz frequency
region in the conventional reciprocating compressor and the
reciprocating compressor of the present invention,
respectively;
[0041] FIG. 9 is a graph of noise changes in 500 Hz frequency
region in the conventional reciprocating compressor and the
reciprocating compressor of the present invention,
respectively;
[0042] FIG. 10 is a view of a part of a second embodiment of the
stator which is the major component of the present invention;
[0043] FIG. 11 is a view of a part of a third embodiment of the
stator which is the major component of the present invention;
[0044] FIG. 12 is a view of a part of a fourth embodiment of the
stator which is the major component of the present invention;
[0045] FIG. 13 is a view of a part of a fifth embodiment of the
stator which is the major component of the present invention;
[0046] FIG. 14 is a view of a part of a sixth embodiment of the
stator which is the major component of the present invention;
[0047] FIG. 15 is a view of a part of a seventh embodiment of the
stator which is the major component of the present invention;
[0048] FIG. 16 is a view of a part of an eighth embodiment of the
stator which is the major component of the present invention;
[0049] FIG. 17 is a view of a part of a ninth embodiment of the
stator which is the major component of the present invention;
[0050] FIG. 18 is a view of a part of a tenth embodiment of the
stator which is the major component of the present invention;
[0051] FIG. 19 is a view of a part of an eleventh embodiment of the
stator which is the major component of the present invention;
[0052] FIG. 20 is a view of a part of a twelfth embodiment of the
stator which is the major component of the present invention;
[0053] FIG. 21 is a view of a part of a thirteenth embodiment of
the stator which is the major component of the present
invention;
[0054] FIG. 22 is a view of a part of a fourteenth embodiment of
the stator which is the major component of the present
invention;
[0055] FIG. 23 is a view showing a state where a fifteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor;
[0056] FIG. 24 is a view showing a state where a sixteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor;
[0057] FIG. 25 is a view showing a state where a seventeenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor;
[0058] FIG. 26 is a view showing a state where an eighteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor;
[0059] FIG. 27 is a view showing a state where a nineteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor;
[0060] FIG. 28 is a perspective view of an embodiment of a linear
compressor according to the present invention; and
[0061] FIG. 29 is a side-sectional view of the embodiment of the
linear compressor according to the present invention.
MODE FOR INVENTION
[0062] FIG. 3 is a sectional view of an embodiment of a
reciprocating compressor according to the present invention.
[0063] As illustrated in FIG. 3, in the embodiment of the
reciprocating compressor according to the present invention, a
compression unit and a motor unit are installed in a hermetic
container 100 to maintain a determined spacing 101. A mounting
plate 110 is provided below the hermetic container 100 and fixes
the hermetic compressor in a determined position below the hermetic
container 100. A terminal mounting portion 120 is installed on one
surface of the hermetic container 100 and supplies power to the
hermetic compressor.
[0064] A suction pipe 130, a discharge pipe 140 and a process pipe
150 are installed on the inside and outside of the hermetic
container 100 such that refrigerant flows therethrough. The suction
pipe 130 penetrates through the hermetic container 100 to transfer
the refrigerant to the inside of the hermetic container 100 and is
installed on the side surface of the terminal mounting portion 120.
The discharge pipe 140 penetrates through the hermetic container
100 in the opposite direction to the terminal mounting portion 120
and discharges the refrigerant from the inside to the outside of
the hermetic container 100. The process pipe 150 is symmetric to
the suction pipe 130 to be positioned on the side surface of the
discharge pipe 140 and becomes a path for injecting oil or
refrigerant into the hermetic container 100.
[0065] A frame 160 is installed in the hermetic container 100, and
various components constituting the compression unit and the motor
unit are installed on the frame 160. The compression unit including
a cylinder 210, a piston 220, a head cover 230 and a valve assembly
240 is installed at an upper portion of the frame 160, and the
motor unit including a stator 320 having an irregular reflection
portion 310, a rotor 330 and a rotating shaft 340 is installed at a
lower portion of the frame 160.
[0066] The compression unit will be described in detail. The
cylinder 210 is provided at the upper side of the frame 160 to
define a compression space therein. The piston 220 is operated in
the cylinder 210 to compress refrigerant in the compression space.
The head cover 230 and the valve assembly 240 are installed
together to block the compression space of the cylinder 210. The
valve assembly 240 controls the refrigerant to be sucked and
discharged into/from the compression space. Moreover, a suction
muffler 250 reduces noise of the refrigerant sucked from the
outside through the suction pipe 130 and transfers the refrigerant
to the compression space through the valve assembly 240. A
discharge muffler 260 is installed at one side of the frame 160 to
communicate with a discharge chamber in the head cover 230 and
reduces pulsation and noise of the refrigerant compressed in the
compression space. A loop pipe 270 connects the discharge muffler
260 to the discharge pipe 140 and transfers the refrigerant.
[0067] The motor unit will be described in detail. The irregular
reflection portion 310 dissipates noise and vibration by preventing
the noise and vibration colliding against an inner surface of the
hermetic container 100 from being reflected again to the inner
surface of the hermetic container 100. The irregular reflection
portion 310 is formed on an outer circumferential surface of the
stator 320 adjacent to the inner surface of the hermetic container
100 and includes one or more of a concave groove and a convex
protrusion. The stator 320 is fixed to define a determined spacing
101 with the inner surface of the hermetic container 100. The outer
circumference of the stator 320 may be formed in various shapes
such as a polygon having four plane portions, a circle, a
quadrangle, and so on. The irregular reflection portion 310 may be
integrally formed with an outer circumferential surface of the
stator 320, or separately formed and attached thereto, regardless
of the shape of the stator 320. Various embodiments of the
irregular reflection portion 310 will be described later below. The
rotor 330 maintains an interval from the inside of the stator 320.
As the stator 320 is supplied with current, the rotor 330 is
rotated by an electromagnetic force. The rotating shaft 340 is
press-fit into the center of the rotor 330 to penetrate through the
frame 160 and rotated with the rotor 330. Further, a connecting rod
350 connects a top end of the rotating shaft 340 to the piston 220
and converts the rotational force of the rotor 330 and the rotating
shaft 340 into the linear reciprocating motion of the piston
220.
[0068] The operation of the reciprocating compressor according to
the present invention will be described in detail.
[0069] Power is supplied to the terminal mounting portion 120
mounted on one surface of the hermetic container 100. As the power
is supplied to the stator 320, the rotor 330 is rotated with the
rotating shaft 340 by the electromagnetic interaction with the
stator 320.
[0070] The rotational motion of the rotating shaft 340 is converted
into the linear reciprocating motion by the connecting rod 350 and
transferred to the piston 220, such that the piston 220 is linearly
reciprocated between the top dead center and the bottom dead center
in the compression space of the cylinder 210.
[0071] The linear reciprocating motion of the piston 220 changes a
pressure in the compression space. If the piston 220 moves from the
top dead center to the bottom dead center, the pressure of the
compression space becomes lower than that of the suction muffler
250, and thus a suction valve of the valve assembly 240 is open.
The refrigerant of the suction pipe 130 and the suction muffler 250
is introduced into the compression space until the pressure of the
suction muffler 250 is the same as the pressure of the compression
space. On the contrary, if the piston 220 moves from the bottom
dead center to the top dead center, the pressure of the compression
space continuously rises. When the pressure reaches a determined
discharge pressure, a discharge valve of the valve assembly 240 is
open. The refrigerant compressed into a high pressure in the
compression space is discharged through the discharge chamber of
the head cover 230 along the discharge muffler 260, the loop pipe
270 and the discharge pipe 140. When the reciprocating compressor
is operated, vibration and noise are generated by its components.
As illustrated in FIG. 3, reflection directions of the
noise/vibration generated in the hermetic container 100 are
indicated by arrows B-X in the irregular reflection portion
310-provided region. Although noise/vibration is reduced in the
spacing 101 in the hermetic container 100 on each face of the
stator 320 having the irregular reflection portion 310 like B-X,
only one side is illustrated in the drawing and described below in
detail.
[0072] More specifically, noise/vibration/sound wave/frequency is
generated during the operation of the reciprocating compressor such
that the hermetic container 100 is vibrated in X and Y directions
of the spacing 101. A lot of vibration/noise is generated in Y
direction which is the vibration direction of the compressor in
which the piston 220 is linearly reciprocated. The noise/frequency
of the components collides against an inner circumferential surface
of the hermetic container 100 through the spacing 101 and is
vibrated in the spacing 101 in X and Y directions. The
noise/frequency colliding against the inner circumferential surface
of the hermetic container 100 may be emitted to the outside of the
hermetic container 100 as noise. However, the noise/frequency in
the hermetic container 100 is irregularly reflected by the
irregular reflection portion 310 and dissipated.
[0073] FIGS. 4 and 5 are a front view and a side view of a stator
applied to the embodiment of the reciprocating compressor according
to the present invention. As illustrated in FIGS. 4 and 5, an
irregular reflection portion 310 including a plurality of concave
grooves 311 is formed on each face of the stator 320. Preferably,
the stator 320 including the irregular reflection portion 310 is
made of a metal material reflecting noise and vibration. A plane
portion 321 is provided on each face of the outer circumference of
the stator 320. The stator 320 is generally formed in the shape of
a quadrangle and shaped into a polygon with rounded edges. A hollow
portion 322 is provided in the stator 320. A plurality of slots 323
are provided radially from the hollow portion 322. A coil is wound
through the slots 323. In the irregular reflection portion 310
(310a, 310b, 310c and 310d), a plurality of grooves 311 are formed
in each plane portion 321 of the stator 320 in a determined
pattern. For example, 13 semicircular grooves having a diameter of
3 mm are formed at regular intervals as the grooves 311 of the
irregular reflection portion 310. Here, the grooves 311 are formed
in the plane portions 321 of the stator 320 toward the hollow
portion 222.
[0074] The irregular reflection portions 310 (310a, 310b, 310c and
310d) are formed to be symmetric in the horizontal or vertical
direction with respect to the plane portions 321 of the stator 320,
respectively. That is, the two irregular reflection portions 310a
and 310b are provided on the plane portions 321 of the stator 320
which are parallel to the actual vibration direction of the
reciprocating compressor, and the two irregular reflection portions
310c and 310d are provided on the plane portions 321 of the stator
320 which are perpendicular to the actual vibration direction of
the reciprocating compressor. It is to be noted that the irregular
reflection portion 310 (310a, 310b, 310c and 310d) may be formed on
at least one of the plane portions 321 of the stator 320. Since
noise and vibration are significantly generated in the actual
vibration direction during the operation of the reciprocating
compressor, they can be considerably reduced by the irregular
reflection portions 310a and 310b provided in the actual vibration
direction.
[0075] The irregular reflection portion 310 (310a, 310b, 310c and
310d) is formed in the shape of a series of grooves.
Noise/frequency/vibration/sound wave generated during the operation
of the compressor is reflected by the inner circumferential surface
of the hermetic container 100 (refer to FIG. 3) to the grooves 311,
successively reflected in the grooves 311, and gradually
dissipated. Some noise is reflected from the inside to the outside
of the grooves 311 and moved to the inner circumferential surface
of the hermetic container 100. However, as the noise is reflected
by the inside of the grooves 331 at a certain angle and collides
against the inner circumferential surface of the hermetic container
100 (refer to FIG. 3), it is gradually reduced. Therefore, the
diameter of the grooves 311 of the irregular reflection portion 310
is calculated by the formula (f=c/.lamda.), wherein f represents a
frequency, c a sound speed of refrigerant, and .lamda. a diameter
of the groove 311. For example, according to the present invention,
the diameter of the grooves 311 of the irregular reflection portion
310 is 3 mm to reduce low frequencies of 400 Hz to 500 Hz.
[0076] Accordingly, the noise and vibration generated by the
components during the operation of the reciprocating compressor are
reflected by the inner circumferential surface of the hermetic
container 100 (refer to FIG. 3), and then reflected by the grooves
311 of the irregular reflection portion 310. Some of them are
discharged to the outside of the grooves 311 of the irregular
reflection portion 310, but the other are successively reflected in
the grooves 311 of the irregular reflection portion 310. As a
result, the noise and vibration are gradually dissipated.
[0077] FIG. 6 is a graph of noise levels by X-direction frequencies
in the conventional reciprocating compressor and the reciprocating
compressor of the present invention, respectively.
[0078] In the graph of FIG. 6, noise was measured 30 cm apart from
the reciprocating compressor in the direction (hereinafter, X
direction) perpendicular to the vibration direction of the
reciprocating compressor during the operation of the reciprocating
compressor. While A indicates noise changes in the conventional
reciprocating compressor in which the irregular reflection portion
is not provided on the plane portion of the stator as illustrated
in FIG. 2, B indicates noise changes in the reciprocating
compressor of the present invention in which the irregular
reflection portion is provided on the plane portion of the stator
as illustrated in FIG. 4. According to the result of measuring
noise in X direction, large changes occurred in high frequency
regions of 1 k to 1.6 k and 2.5 kHz. The reciprocating compressor
of the present invention reduced the high-frequency noise more than
the conventional reciprocating compressor by about 5 to 10 dB.
[0079] FIG. 7 is a graph of noise levels by Y-direction frequencies
in the conventional reciprocating compressor and the reciprocating
compressor of the present invention, respectively.
[0080] In the graph of FIG. 7, noise was measured 30 cm apart from
the reciprocating compressor in the direction (hereinafter, Y
direction) parallel to the vibration direction of the reciprocating
compressor during the operation of the reciprocating compressor.
While C indicates noise changes in the conventional reciprocating
compressor in which the irregular reflection portion is not
provided on the plane portion of the stator as illustrated in FIG.
2, D indicates noise changes in the reciprocating compressor of the
present invention in which the irregular reflection portion is
provided on the plane portion of the stator as illustrated in FIG.
4. According to the result of measuring noise in Y direction, the
reciprocating compressor of the present invention reduced noise
more than the conventional reciprocating compressor by about 5 to
10 dB in frequency regions of 400 Hz to 500 Hz, 1 k to 1.6 k and
2.5 kHz, respectively. While the high-frequency region has a short
arrival distance by using short waves, the low-frequency region has
a long arrival distance by using long waves. Therefore, the
low-frequency noise is sensed greater than the high-frequency
noise. However, according to the result of measuring noise in Y
direction, the reciprocating compressor of the present invention
reduced noise more than the conventional reciprocating compressor
in the low-frequency region of 400 Hz to 500 Hz as in the
high-frequency region, thereby reducing the sensory noise.
[0081] FIG. 8 is a graph of noise changes in 400 Hz frequency
region in the conventional reciprocating compressor and the
reciprocating compressor of the present invention, respectively,
and FIG. 9 is a graph of noise changes in 500 Hz frequency region
in the conventional reciprocating compressor and the reciprocating
compressor of the present invention, respectively.
[0082] The graphs of FIGS. 8 and 9 illustrate the noise reduction
effect in 400 Hz and 500 Hz frequency regions generated by the
resonance in the inner space of the reciprocating compressor. In
FIGS. 8 and 9, while I indicates noise in the conventional
reciprocating compressor in which the irregular reflection portion
is not provided on the plane portion of the stator as illustrated
in FIG. 2, II indicates noise in the reciprocating compressor of
the present invention in which the irregular reflection portion is
provided on the plane portion of the stator as illustrated in FIG.
4. Here, the reciprocating compressor of the present invention
reduced noise more than the conventional reciprocating compressor
in 400 Hz frequency region by average of 8 dB and in 500 Hz
frequency region by average of 10 dB. As described above, the
low-frequency regions of 400 Hz and 500 Hz have a long arrival
distance by using long waves, and thus easily operate as a noise
source in the reciprocating compressor. However, even if
frequencies of the low-frequency region are generated, the
compressor of the present invention which includes the irregular
reflection portion can reduce noise more than the conventional
compressor which does not include the irregular reflection portion
by about 8 to 10 dB.
[0083] FIG. 10 is a view of a part of a second embodiment of the
stator which is the major component of the present invention.
[0084] As illustrated in FIG. 10, in the second embodiment of the
stator, an irregular reflection portion 310 in which a plurality of
polygonal grooves 312 are arranged at regular intervals is
integrally formed with a plane portion 321 formed on an outer
circumferential surface of the stator 320. Here, the section of the
grooves 312 has a `` shape having two faces. The grooves 312 are
formed on the outer circumferential surface of the stator 320 to be
symmetric in a certain pattern. In addition, the width and depth of
the grooves 312 are set to irregularly reflect low frequencies
generated in the components. For example, 13 grooves 312 having a
width of 3 mm may be used.
[0085] FIG. 11 is a view of a part of a third embodiment of the
stator which is the major component of the present invention.
[0086] As illustrated in FIG. 11, in the third embodiment of the
stator, an irregular reflection portion 310 in which a plurality of
polygonal protrusions 312' are arranged at regular intervals is
integrally formed with a plane portion 321 formed on an outer
circumferential surface of the stator 320. Here, the section of the
protrusions 312' has a `` shape having two faces and the width of
the protrusions 312' is constantly reduced from the plane portion
321 to the outside (or in the radial direction). Moreover, the
width and length of the protrusions 312' are set to irregularly
reflect low frequencies generated in the components. For example,
13 protrusions 312' having a width of 3 mm may be used.
[0087] FIG. 12 is a view of a part of a fourth embodiment of the
stator which is the major component of the present invention.
[0088] As illustrated in FIG. 12, in the fourth embodiment of the
stator, an irregular reflection portion 310 in which a plurality of
semicircular protrusions 311' are arranged at regular intervals is
integrally formed with a plane portion 321 formed on an outer
circumferential surface of the stator 320. Here, the section of the
protrusions 311' has a semicircular shape. The protrusions 311'
protrude radially from the plane portion 321. Additionally, the
diameter of the protrusions 311' is set to irregularly reflect low
frequencies generated in the components. For example, 13
protrusions 311' having a diameter of 3 mm may be used.
[0089] FIG. 13 is a view of a part of a fifth embodiment of the
stator which is the major component of the present invention.
[0090] As illustrated in FIG. 13, in the fifth embodiment of the
stator, an irregular reflection portion 310 in which semicircular
grooves 311 and semicircular protrusions 311' are alternately
arranged is integrally formed with a plane portion 321 formed on an
outer circumferential surface of the stator 320. Here, the grooves
311 are formed in the plane portion 321 of the stator 320 toward
the hollow portion 322 (refer to FIG. 4), and the protrusions 311'
protrude radially from the stator 320 and are formed on both sides
of the grooves 311. In addition, the diameter of the grooves 311
and the diameter of the protrusions 311' are set to irregularly
reflect low frequencies generated in the components. For example,
12 semicircular grooves 311 having a diameter of 3 mm may be formed
between 13 semicircular protrusions 311' having a diameter of 3 mm,
respectively. It is obvious that the grooves or protrusions
constituting the irregular reflection portion 310 may be formed in
various shapes and numbers according to frequencies generated in
the compressor.
[0091] FIG. 14 is a view of a part of a sixth embodiment of the
stator which is the major component of the present invention.
[0092] As illustrated in FIG. 14, in the sixth embodiment of the
stator, an irregular reflection portion 310 in which a plurality of
concave grooves 313 and a plurality of guide portions 314 reducing
the width of the entrances of the grooves 313 are alternately
arranged is integrally formed with a plane portion 321 formed on an
outer circumferential surface of the stator 320. Here, the section
of the grooves 313 has a circular shape with an open entrance. The
guide portions 314 are regularly formed to narrow the width of the
entrances of the grooves 313 such that noise is successively
reflected in the grooves 313 and dissipated. Moreover, the diameter
of the grooves 313 is set to irregularly reflect low frequencies
generated in the components. For example, 13 grooves 313 having a
maximum diameter of 3 mm may be formed at regular intervals, and
guide portions 314 reducing the width of the entrances of the
grooves 313 may be provided between the grooves 313, respectively.
FIGS. 15 and 16 are views of parts of seventh and eighth
embodiments of the stator which is the major component of the
present invention, respectively. As illustrated in FIG. 15, in the
seventh embodiment of the stator, an irregular reflection portion
310 in which a plurality of polygonal grooves 315 are arranged at
regular intervals is integrally formed with a plane portion 321. As
illustrated in FIG. 16, in the eighth embodiment of the stator, an
irregular reflection portion 310 in which a plurality of polygonal
protrusions 315' are arranged at regular intervals is integrally
formed with a plane portion 321. Here, the sectional shape of the
grooves 315 and the sectional shape of the protrusions 315' are
identically a plurality of straight faces (or polygons). The width
of the grooves 315 is increased toward the hollow portion 322
(refer to FIG. 4) of the stator 320 and then decreased, and the
width of the protrusions 315' is increased in the radial direction
of the stator 320 and then decreased. In addition, the width of the
grooves 315 and the width of the protrusions 315' are set to
irregularly reflect low frequencies generated in the components.
For example, 13 grooves 315 having a maximum diameter of 3 mm may
be used, or 13 protrusions 315' having a maximum diameter of 3 mm
may be used.
[0093] Accordingly, when noise generated during the operation of
the compressor is reflected by the inner surface of the hermetic
container 100 (refer to FIG. 3), if the reflected noise is
introduced into the grooves 315, it is successively reflected by
the straight faces of the grooves 315 and dissipated, or if the
reflected noise is introduced between the protrusions 315', it is
repeatedly reflected by the straight faces of the protrusions 315'
and dissipated.
[0094] FIGS. 17 and 18 are views of parts of seventh and eighth
embodiments of the stator which is the major component of the
present invention, respectively. As illustrated in FIG. 17, in the
ninth embodiment of the stator, an irregular reflection portion 310
in which grooves 316 including curved portions are arranged at
regular intervals is integrally formed with a plane portion 321. As
illustrated in FIG. 18, in the tenth embodiment of the stator, an
irregular reflection portion 310 in which protrusions 316'
including curved portions are arranged at regular intervals is
integrally formed with a plane portion 321. Here, straight faces
having the same height as the plane portion 321 are provided
between the grooves 316 and between the protrusions 316'. For
example, the grooves 316 or the protrusions 316' may be formed in
the shape of a curved portion between the straight faces having the
same height as the plane portion 321 of the stator 320.
[0095] FIG. 19 is a view of a part of an eleventh embodiment of the
stator which is the major component of the present invention.
[0096] As illustrated in FIG. 19, in the eleventh embodiment of the
stator, an irregular reflection portion 310 in which a plurality of
protrusions 312' are arranged in a certain pattern is integrally
formed with a plane portion 321. Here, the pattern is to arrange
three protrusions 312' formed in the shape of `` having two
straight faces. These patterns may be formed on the plane portion
321 at regular intervals. Meanwhile, grooves may be formed in the
above pattern like the protrusions 312'.
[0097] FIG. 20 is a view of a part of a twelfth embodiment of the
stator which is the major component of the present invention.
[0098] As illustrated in FIG. 20, in the twelfth embodiment of the
stator, an irregular reflection portion 310 in which protrusions
312' are arranged with the number increasing toward the center is
integrally formed with a plane portion 321. For example, four
protrusions 312' having a sectional shape of `` may be successively
formed in the center of the plane portion 321, and one protrusion
312' may be arranged on parts of the plane portion 321 spaced apart
from the protrusions 312' by a certain interval. In the meantime,
grooves may be formed in the above pattern like the protrusions
312'.
[0099] FIG. 21 is a view of a part of a thirteenth embodiment of
the stator which is the major component of the present
invention.
[0100] As illustrated in FIG. 21, in the thirteenth embodiment of
the stator, an irregular reflection portion 310 in which two
successive protrusions 312' are formed in the center and four
successive protrusions 312' are formed at positions spaced apart
from the two protrusions 312' is integrally formed with a plane
portion 321. In addition, grooves may be formed in the above
pattern like the protrusions 312'.
[0101] The irregular reflection portions 310 applied to the
embodiments of the stator of FIGS. 19 to 21 are nothing but
exemplary embodiments. The grooves or the protrusions may be formed
in various shapes and patterns and changed according to the kind,
specification and the like of the compressor.
[0102] FIG. 22 is a view of a fourteenth embodiment of the stator
which is the major component of the present invention.
[0103] As illustrated in FIG. 22, the fourteenth embodiment of the
stator is the same as the conventional stator. An irregular
reflection portion 310 (310a, 310b, 310c and 310d) may be
separately formed and attached to a plane portion 321 of the stator
320.
[0104] Four plane portions 321 are provided on the outer
circumference of the stator 320. The stator 320 is formed in the
shape of a polygon with rounded edges. A hollow portion 322 is
provided in the stator 320. Slots 323 are provided radially from
the hollow portion 322.
[0105] In the irregular reflection portion 310, a plurality of
protrusions 311' are arranged at regular intervals. The irregular
reflection portion 310 is manufactured as an independent component
and attached to each plane portion 321 of the stator 320. Here, the
two irregular reflection portions 310a and 310b are attached to the
plane portions 321 of the stator 320 which are positioned in the
direction (Y direction of FIG. 3) parallel to the vibration
direction of the compressor, and the other two irregular reflection
portions 310c and 310d are attached to the plane portions 321 of
the stator 320 which are positioned in the direction (X direction
of FIG. 3) perpendicular to the vibration direction of the
compressor. However, the irregular reflection portion 310 may be
mounted in at least one of the vibration direction of the
compressor and the direction perpendicular to the vibration
direction. For example, the irregular reflection portion 310 may be
formed of 13 protrusions 311' arranged at regular intervals and
attached to the plane portions 321 of the stator 320 to be
symmetric.
[0106] Further, the irregular reflection portion 310 may be formed
in the shapes, numbers or patterns applied to the second to the
thirteenth embodiments. As described above, noise is successively
reflected in the irregular reflection portion 310, and thus
dissipated.
[0107] FIG. 23 is a view showing a state where a fifteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor.
[0108] As illustrated in FIG. 23, a quadrangular stator 320 is
mounted in an elliptical hermetic container 100. An irregular
reflection portion 310 is provided on a plane portion 321 of the
stator 320.
[0109] The hermetic container 100 forms a determined hermetic space
and includes components such as the stator 320. The section of the
hermetic container 100 has a circular shape. A spacing 101 is
defined between the hermetic container 100 and the mounted stator
320.
[0110] The stator 320 is formed in the shape of a quadrangle with
four faces. Irregular reflection portions 310 (310a, 310b, 310c and
310d) are provided to be symmetric on the plane portions 321 which
are outer circumferential surfaces of the stator 320. Here, in
order to improve the noise reduction effect of the irregular
reflection portions 310 (310a, 310b, 310c and 310d), the plane
portions 321 of the stator 320 having the irregular reflection
portions 310 (310a, 310b, 310c and 310d) are preferably formed in
the vibration direction (Y direction) of the compressor or the
direction (X direction) perpendicular thereto.
[0111] The irregular reflection portions 310 (310a, 310b, 310c and
310d) include both the irregular reflection portions 310a and 310b
formed in the vibration direction (Y direction) of the compressor
and the irregular reflection portions 310c and 310d formed in the
direction (X direction) perpendicular to the vibration direction of
the compressor, but may include at least one of them. For example,
an irregular reflection portion 310 in which 13 grooves 311 are
formed at regular intervals may be provided on each of the four
plane portions 321 of the stator 320.
[0112] Accordingly, as the hermetic container 100 is excited in Y
direction during the operation of the compressor,
noise/vibration/frequency is generated in the vibration direction
(Y direction) or the direction (X direction) perpendicular to the
vibration direction, vibrated in the spacing 101 between the inner
circumferential surface of the hermetic container 100 and the
stator 320, and reflected between the inner circumferential surface
of the hermetic container 100 and the irregular reflection portion
310 of the stator 320. Here, the noise is successively reflected in
the grooves 311 of the irregular reflection portion 310, and thus
gradually dissipated. Even if the noise is reflected by the inside
of the grooves 311 of the irregular reflection portion 310 to the
inner circumferential surface of the hermetic container 100, since
the noise is bent at a determined angle, it is reduced. The above
process is repeated to reduce the noise generated in the spacing
101 of the hermetic container 100.
[0113] FIG. 24 is a view showing a state where a sixteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor.
[0114] As illustrated in FIG. 24, a circular stator 320 is mounted
in an elliptical hermetic container 100. An irregular reflection
portion 310 is provided on an outer circumferential surface 321' of
the stator 320.
[0115] The section of the hermetic container 100 has a circular
shape. A spacing 101 is defined between the hermetic container 100
and the mounted stator 320. The stator 320 is formed in the shape
of a circle. Irregular reflection portions 310 (310a, 310b, 310c
and 310d) are provided on the outer circumferential surface 321' of
the stator 320 to be symmetric.
[0116] The irregular reflection portion 310 (310a, 310b, 310c and
310d) may be formed in the vibration direction (Y direction) of the
compressor or the direction (X direction) perpendicular to the
vibration direction of the compressor and may be formed in some
part of them. For example, an irregular reflection portion 310 in
which 13 grooves 311 are formed at regular intervals may be
provided on four parts of the outer circumferential surface 321' of
the stator 320, i.e., in the vibration direction (Y direction) of
the compressor and the direction (X direction) perpendicular
thereto, respectively.
[0117] FIGS. 25 and 26 are views showing a state where seventeenth
and eighteenth embodiments of the stator which is the major
component of the present invention are used in a reciprocating
compressor, respectively. As illustrated in FIGS. 25 and 26, a
polygonal stator 320 is mounted in a circular hermetic container
100'. An irregular reflection portion 310 is provided on a plane
portion 321 of the stator 320.
[0118] The section of the hermetic container 100' has a circular
shape. A spacing 101 is defined between the hermetic container 100'
and the mounted stator 320. As illustrated in FIG. 25, the stator
320 may be formed in the shape of a quadrangle with four faces and
shaped into a polygon with rounded edges, or as illustrated in FIG.
26, the stator 320 may be formed in the shape of a quadrangle with
four faces. Irregular reflection portions 310 (310a, 310b, 310c and
310d) are provided to be symmetric on the plane portions 321 which
are outer circumferential surfaces of the stator 320. Here, in
order to improve the noise reduction effect of the irregular
reflection portions 310 (310a, 310b, 310c and 310d), the plane
portions 321 of the stator 320 including the irregular reflection
portions 310 (310a, 310b, 310c and 310d) are preferably formed in
the vibration direction (Y direction) of the compressor or the
direction (X direction) perpendicular thereto.
[0119] The irregular reflection portions 310 (310a, 310b, 310c and
310d) include both the irregular reflection portions 310a and 310b
formed in the vibration direction (Y direction) of the compressor
and the irregular reflection portions 310c and 310d formed in the
direction (X direction) perpendicular to the vibration direction of
the compressor, but may include at least one of them. For example,
an irregular reflection portion 310 in which 13 grooves 311 are
formed at regular intervals may be provided on each of the four
plane portions 321 of the stator 320.
[0120] FIG. 27 is a view showing a state where a nineteenth
embodiment of the stator which is the major component of the
present invention is used in a reciprocating compressor.
[0121] As illustrated in FIG. 27, a circular stator 320 is mounted
in a circular hermetic container 100'. An irregular reflection
portion 310 is provided on the entire outer circumferential surface
of the stator 320.
[0122] The irregular reflection portion 310 is formed of grooves
311 but may be formed of protrusions. Here, the irregular
reflection portion 310 may be formed on the outer circumferential
surface of the stator 320 in either the vibration direction (Y
direction) of the compressor or the direction (X direction)
perpendicular thereto, but may be formed on the entire outer
circumferential surface of the stator 320 to improve the noise
reduction effect and increase the surface area to improve the
radiation effect of a motor.
[0123] FIGS. 28 and 29 are a perspective view and a side-sectional
view of an embodiment of a linear compressor according to the
present invention. As illustrated in FIGS. 28 and 29, in the
embodiment of the linear compressor according to the present
invention, a compression mechanism unit and a motor unit are
installed in a hermetic container 500 to maintain a determined
spacing 501. A determined irregular reflection portion is provided
on an outer circumferential surface of the motor unit.
[0124] The hermetic container 500 is formed in the shape of a
sphere to provide a receiving space. Oil is stored in a lower
portion of the hermetic container 500 and supplied to the
compression mechanism unit to perform lubrication and cooling. The
compression mechanism unit is elastically supported by four springs
510 at the lower portion of the hermetic container 500. This
prevents vibration of the compression mechanism unit from being
transferred to the hermetic container 500.
[0125] The compression mechanism unit includes a cylinder 620
integrally formed with a frame 610, and a piston 630. The frame 610
is generally manufactured by A1 die-casting, and the following
components are installed thereon. The cylinder 620 may be
integrally formed with the frame 610 or insert-injection-molded and
may have a compression space therein. One end of the piston 630
inserted into the cylinder 620 is blocked and provided with an
inlet port 630h communicating with the compression space, and the
other end of the piston 630 which is not inserted into the cylinder
620 is opened and expanded in the radius direction. Here, a thin
suction valve 640 is installed on the inlet port 630h of the piston
630 to be opened and closed, and a suction muffler 650 and a
supporter 660 are mounted at the open end of the piston 630. The
suction muffler 650 not only guides the flow of refrigerant but
also reduces noise caused by the flow of the refrigerant and the
opening and closing of the valve. The supporter 660 elastically
supports the piston 630 in the motion direction using springs S. In
addition, a discharge valve assembly 670 including a discharge
valve 671, a discharge cover 672 and a discharge valve spring 673
is installed at one end communicating with the compression space of
the cylinder 620 to be opened and closed.
[0126] The motor unit includes an inner stator 710, an outer stator
720, a permanent magnet 730, and a connection member 740. The inner
stator 710 is formed by stacking a plurality of laminations in the
circumferential direction. The inner stator 710 is fixed to an
outer circumferential surface of the cylinder 620 by a fixing ring
(not shown). The outer stator 720 includes a coil winding body 721
around which a coil is wound in the circumferential direction, and
core blocks 722 coupled to the coil winding body 721 at regular
intervals in the circumferential direction. The core block 722 is
formed by stacking laminations in some section in the
circumferential direction. The outer stator 720 is fixed to
maintain a determined interval in the outer circumferential
direction of the inner stator 710. As a motor cover 680 is
bolt-fastened to the frame 610, the outer stator 720 is fixed in
the axial direction. The permanent magnet 730 is fixed to the
connection member 740 and maintains a gap between the inner stator
710 and the outer stator 720. The connection member 740 is
installed to connect the permanent magnet 730 to the piston
630.
[0127] An irregular reflection portion 750 is formed on the core
block 722 of the outer stator 720. In a state where the core blocks
722 are mounted on the coil winding body 721, the irregular
reflection portion 750 is formed on their radial surfaces. The
irregular reflection portion 750 includes one or more of a groove
751 and a protrusion. In the embodiment of the linear compressor
according to the present invention, an irregular reflection portion
750 including a plurality of grooves 751 is integrally formed with
an outer circumferential surface of the outer stator 720. The
irregular reflection portion 750 may include various patterns of
the grooves 751 or the protrusions, and may be manufactured as a
separate component and attached to the outer circumferential
surface of the outer stator 720.
[0128] Particularly, the diameter of the grooves 751 of the
irregular reflection portion 750 is subject to the formula
(f=c/.lamda.), wherein f represents a frequency, c a sound speed of
refrigerant, and .lamda. a diameter of the groove 751. According to
the present invention, the diameter of the grooves 751 is
determined to reduce low frequencies of 400 Hz to 500 Hz.
[0129] The operation of the linear compressor so constructed is as
follows. When power is supplied to the coil winding body 721, the
permanent magnet 730 is linearly reciprocated between the inner
stator 710 and the outer stator 720 by an electromagnetic force.
Noise/vibration/sound wave/frequency (hereinafter, referred to as
`noise`) is generated in the respective components of the hermetic
container 500 during the operation of the linear compressor and
excited in the spacing 501 of the hermetic container 500. However,
since the irregular reflection portion 750 is provided on the outer
surface of the outer stator 720, the noise generated in the
respective components collides against the inner circumferential
surface of the hermetic container 500 and is reflected to the
irregular reflection portion 750 of the outer stator 720. Here, the
noise is successively reflected in the grooves 751 of the irregular
reflection portion 750 and dissipated. Even if the noise is
reflected from the inside to the outside of the grooves 751, it
collides against the inner circumferential surface of the hermetic
container 500 at a certain angle, and thus is gradually
reduced.
[0130] As discussed earlier, the irregular reflection portion
applied to the reciprocating compressor or the linear compressor
may include a plurality of grooves and protrusions, and the grooves
and the protrusions may be formed in specific shapes and certain
patterns, which are nothing but exemplary embodiments of the
present invention. It is to be noted that modifications in the
number, shape and pattern of the grooves and the protrusions can be
made within the scope of the present invention.
[0131] Therefore, according to the present invention, the noise
generated during the driving of the compressor is repeatedly
reflected in the irregular reflection portion or reflected to the
outside of the irregular reflection portion at a specific angle. It
is thus possible to reduce noise. In addition, the compressor
includes the irregular reflection portion increasing the surface
area on the outer circumferential surface of the motor unit, and
thus improves the radiation effect of the motor unit and reduces
the temperature of sucked refrigerant affected by the temperature
of the motor unit. It is thus possible to improve efficiency of the
compressor.
[0132] The present invention has been described in connection with
the exemplary embodiments and the accompanying drawings. However,
the scope of the present invention is not limited thereto but is
defined by the appended claims.
* * * * *