U.S. patent application number 10/855496 was filed with the patent office on 2004-12-09 for linear compressor.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Kim, Jin Dong, Kim, Jung Woo, Kim, Kwang Wook, Song, Gye Young.
Application Number | 20040247457 10/855496 |
Document ID | / |
Family ID | 33487875 |
Filed Date | 2004-12-09 |
United States Patent
Application |
20040247457 |
Kind Code |
A1 |
Kim, Kwang Wook ; et
al. |
December 9, 2004 |
Linear compressor
Abstract
Disclosed herein is a linear compressor. The linear compressor
comprises a cylinder provided at one side thereof with an outlet
part, and a piston reciprocated in the cylinder by means of a liner
motor for compressing a fluid. The piston has a fluid flow channel
formed therethrough. The fluid flow channel communicates with the
interior of the cylinder. To the rear part of the piston is fixedly
attached a first muffler so that the first muffler is linearly
moved along with the piston. The first muffler has a fluid flow
channel formed therein. The fluid flow channel of the first muffler
communicates with the fluid flow channel of the piston. The first
muffler also has a noise-reducing space defined therein. In the
compressor is fixedly mounted a second muffler such that the inner
volume of the second muffler is variable as the first muffler is
linearly moved. The second muffler has a fluid flow channel formed
therein. The fluid flow channel of the second muffler communicates
with the fluid flow channel of the first muffler. The second
muffler also has a noise-reducing space defined therein. According
to the present invention, introduction efficiency of the linear
compressor is improved, and noise generated at various bands is
effectively reduced.
Inventors: |
Kim, Kwang Wook; (Seoul,
KR) ; Kim, Jin Dong; (Kyungki-do, KR) ; Song,
Gye Young; (Kyungki-do, KR) ; Kim, Jung Woo;
(Seoul, KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
LG Electronics Inc.
Seoul
KR
|
Family ID: |
33487875 |
Appl. No.: |
10/855496 |
Filed: |
May 28, 2004 |
Current U.S.
Class: |
417/312 ;
417/416 |
Current CPC
Class: |
F04B 35/045 20130101;
F04B 39/0055 20130101 |
Class at
Publication: |
417/312 ;
417/416 |
International
Class: |
F04B 049/00; F04B
039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 2003 |
KR |
2003-35936 |
Claims
What is claimed is:
1. A linear compressor comprising: a cylinder provided at one side
thereof with an outlet part; a piston reciprocated in the cylinder
by means of a liner motor for compressing a fluid, the piston
having a fluid flow channel formed therethrough, the fluid flow
channel communicating with the interior of the cylinder; a first
muffler fixedly attached to the rear part of the piston so that the
first muffler is linearly moved along with the piston, the first
muffler having a fluid flow channel formed therein, the fluid flow
channel of the first muffler communicating with the fluid flow
channel of the piston, the first muffler also having a
noise-reducing space defined therein; and a second muffler fixedly
mounted in the compressor such that the inner volume of the second
muffler is variable as the first muffler is linearly moved, the
second muffler having a fluid flow channel formed therein, the
fluid flow channel of the second muffler communicating with the
fluid flow channel of the first muffler, the second muffler also
having a noise-reducing space defined therein.
2. The compressor as set forth in claim 1, wherein the first
muffler is constructed so that the rear part of the first muffler
is reciprocated while being inserted in the second muffler.
3. The compressor as set forth in claim 2, wherein the gap distance
between the outer circumferential surface of the first muffler and
the inner circumferential surface of the second muffler is 0.1 to
1.0 mm.
4. The compressor as set forth in claim 1, wherein the first
muffler is formed in the shape of a cylinder having fluid flow
holes formed through the front and rear parts thereof,
respectively, so that the fluid passes through the fluid flow
holes.
5. The compressor as set forth in claim 1, wherein the second
muffler is formed in the shape of a cylinder, the cylinder being
opened at the front part thereof so that the first muffler is
inserted into the second muffler, the cylinder having an inlet hole
formed therethrough so that the fluid is introduced through the
inlet hole.
6. The compressor as set forth in claim 1, wherein the first
muffler is provided with a Helmholtz resonator.
7. The compressor as set forth in claim 6, wherein the Helmholtz
resonator has a space formed at the inner circumference of the
first muffler in the circumferential direction.
8. The compressor as set forth in claim 1, wherein at least one of
the first muffler and the second muffler has a collection space
formed internally at the rear part thereof.
9. The compressor as set forth in claim 8, wherein the collection
space is formed in the vicinity of an inlet pipe where the hole of
the first muffler or the second muffler is extended toward the
interior of the muffler.
10. The compressor as set forth in claim 9, wherein the inlet pipe
is gradually expanded toward the rear part thereof.
11. The compressor as set forth in claim 1, further comprising a
back cover fixed to the rear part of the linear motor, the back
cover having an opening formed at the center part thereof, wherein
the second muffler is fixedly fitted in the opening of the back
cover.
12. The compressor as set forth in claim 1, wherein at least one of
the first and second mufflers is made of a non-magnetic
material.
13. A linear compressor comprising: a cylinder provided with an
outlet valve; a piston disposed such that the piston is moved
forward/backward in the cylinder, the piston having a fluid flow
channel formed therethrough so that a fluid is introduced into the
interior of the cylinder through the fluid flow channel; a linear
motor mounted in the compressor for reciprocating the piston; a
back cover fixed to the linear motor such that the back cover
surrounds the rear part of the piston, the back cover having an
opening formed at the center part thereof; a first muffler fixedly
attached to the rear part of the piston so that the first muffler
is reciprocated along with the piston, the first muffler having an
inlet hole formed therein so that a fluid is introduced into the
first muffler through the inlet hole of the first muffler, the
inlet hole of the first muffler communicating with the fluid flow
channel of the piston; and a second muffler fixedly mounted to the
back cover such that the inner volume of the second muffler is
variable as the first muffler is reciprocated along with the
piston, the second muffler having an inlet hole formed therein, the
inlet hole of the second muffler communicating with the outside of
the back cover so that the fluid existing outside the back cover is
introduced into the second muffler through the inlet hole of the
second muffler.
14. The compressor as set forth in claim 13, wherein at least one
of the first and second mufflers is made of a non-magnetic
material.
15. The compressor as set forth in claim 13, wherein the first
muffler is constructed so that the rear part of the first muffler
is linearly moved while being inserted in the second muffler.
16. The compressor as set forth in claim 15, wherein the gap
distance between the first muffler and the second muffler is 0.1 to
1.0 mm.
17. The compressor as set forth in claim 13, wherein the first
muffler is provided with a Helmholtz resonator.
18. The compressor as set forth in claim 13, wherein at least one
of the first muffler and the second muffler has a collection space
formed internally at the rear part thereof.
19. The compressor as set forth in claim 18, wherein the collection
space is formed in the vicinity of an inlet pipe where the hole of
the first muffler or the second muffler is extended toward the
interior of the muffler.
20. The compressor as set forth in claim 19, wherein the inlet pipe
is gradually expanded toward the rear part thereof.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a linear compressor, and
more particularly to a linear compressor that is capable of
reducing noise and vibration generated in the course of compressing
a fluid and improving compression efficiency.
[0003] 2. Description of the Related Art
[0004] Generally, a linear compressor is constructed such that a
linear driving force from a linear motor is transmitted to a
piston, which is linearly reciprocated in a cylinder, whereby a
fluid is introduced and compressed.
[0005] FIG. 1 is a longitudinal sectional view showing a
conventional linear compressor.
[0006] As shown in FIG. 1, the conventional linear compressor
includes an inner case 10 mounted inside a hermetically sealed
container 1. The inner case 10 is formed in the shape of a cylinder
having a prescribed length. To one side of the inner case 10 is
fixed a back cover 20 having a fluid inlet channel 18 formed
therein. Inside the inner case 10 is mounted a driving motor 30 for
generating a driving force.
[0007] To the driving motor 30 is connected a piston 40 having a
fluid flow channel 38 formed therein. To the piston 40 is attached
an inlet valve 50 for opening and closing the fluid flow channel
38. To the other side of the inner case 10 is fixed a cylinder
block 60 having a cylinder 58, in which the piston 40 is movably
fitted such that the piston 40 can be moved forward and backward in
the cylinder 58. To the cylinder block 60 is attached an outlet
valve 70 for opening and closing the cylinder 58.
[0008] To the hermetically sealed container 1 is connected an inlet
connection pipe 2, through which a fluid is introduced into the
hermetically sealed container 1 from the outside, in such a manner
that the inlet connection pipe 2 is disposed in the rear of the
fluid inlet channel 18 of the back cover 20.
[0009] The driving motor 30 includes: a stator S comprising an
outer cylindrical laminated core 31, an inner cylindrical laminated
core 32 disposed such that the inner core 32 is spaced apart from
the outer core 31 by a prescribed gap distance, and a coil 33 wound
on the outer core 31; a magnet 34 disposed such that the magnet 34
is moved forward/backward between the outer core 31 and the inner
core 32; and a magnet frame 36 connected to the piston 40 so that
the piston 40 is moved forward/backward when the magnet 34 is moved
forward/backward. The magnet 34 is fixed to the magnet frame
36.
[0010] The outer core 31 is fixedly attached to the back cover 20
in the inner case 10. The inner core 32 is fixedly attached to a
cylindrical connection part 21 formed at the back cover 20. The
magnet 34 is fixed to the outer circumference of the magnet frame
36 while being disposed between the outer core 31 and the inner
core 32.
[0011] The magnet frame 36 is elastically supported by means of a
first spring 37a disposed between the magnet frame 36 and the
cylinder block 60. The piston 40 is elastically supported by means
of a second spring 37b disposed between the piston 40 and the inner
core 32.
[0012] The inlet valve 50 is a plate valve wherein one side of the
plate valve is fixed to the piston 40, and the part of the plate
valve for opening and closing the fluid flow channel 38 of the
piston 40 is elastically bent.
[0013] Consequently, when the piston 40 is moved backward toward
the back cover 120, the part of the inlet valve 50 for opening and
closing the fluid flow channel 38 of the piston 40 is bent in the
direction opposite to the back cover 20 by means of the fluid
existing in the fluid flow channel 38, whereby the fluid flow
channel 38 is opened. On the other hand, when the piston 40 is
moved forward toward the-outlet valve 70, the part of the inlet
valve 50 for opening and closing the fluid flow channel 38 of the
piston 40 is straightened in the direction opposite to the outlet
valve 70 by means of the fluid existing between the inlet valve 50
and the outlet valve 70 and by means of its own elastic force,
whereby the fluid flow channel 38 is closed.
[0014] The outlet valve 70 comprises: an outlet cover 72 mounted to
the cylinder block 60 and connected to an outlet pipe at one side
thereof; and a valve body 76 supported against the outlet valve 72
by means of a spring 74 and disposed such that the valve body 76
makes close contact with the end of the cylinder 58 for opening and
closing the cylinder 58.
[0015] In the above-mentioned linear compressor, the inlet valve 50
is dashed against the piston 40 when the inlet valve 50 is opened
and closed, whereby noise is generated. Also, the valve body 76 is
dashed against the cylinder 58 when the outlet valve 70 is opened
and closed, whereby noise is generated. Such noise is transmitted
to the outside of the hermetically sealed container 1 through the
fluid flow channel 38 of the piston 40, a fluid flow hole of the
inner core 32, and the fluid inlet channel 18 of the back cover 20,
as shown in FIG. 1.
[0016] For this reason, an additional muffler is mounted in such a
noise-transmitting path for preventing the transmission of the
noise to the outside of the hermetically sealed container 1.
[0017] The muffler 80 is fixedly attached to the rear part of the
piston 40 while being spaced apart from the fluid inlet channel 18
of the back cover 20. The muffler 80 has fluid flow holes 82
longitudinally formed therethrough, through which the fluid
introduced through the fluid inlet channel 18 of the back cover 20
is guided into the fluid flow channel 38 of the piston 40. The
muffler 80 is constructed such that the diameter of the middle part
of the fluid flow channel 82 is larger than that of the front and
rear parts of the fluid flow channel 82.
[0018] The operation of the conventional linear compressor with the
above-stated construction will now be described.
[0019] When electric current is supplied to the coil 33, the
driving motor 30 is operated so that the magnet 34 is linearly
reciprocated. The reciprocating movement of the magnet 34 is
transmitted to the piston 40 via the magnet frame 36. As a result,
the piston 40 is linearly reciprocated in the cylinder 58.
[0020] As the piston 40 is linearly reciprocated On the cylinder
41, the outlet valve 70 and the inlet valve 50 are opened and
closed. At this time, the gaseous fluid introduced into the
hermetically sealed container 1 is guided into the cylinder 58
through the fluid inlet channel 18 of the back cover 20, the fluid
flow channel of the inner core 32, the muffler 80, and the fluid
flow channel 38 of the piston 40. In the cylinder 58, the gaseous
fluid is compressed and then discharged. The discharged
high-temperature and high-pressure fluid gas is discharged to the
outside of the hermetically sealed container 1 through a
discharging pipe (not shown).
[0021] In the above-mentioned conventional linear compressor,
however, the muffler 80 is reciprocated along with the piston 40
while being spaced apart from the fluid inlet channel 18 of the
back cover 20. As a result, the fluid introduced through the fluid
inlet channel 18 of the back cover 20 is not quickly guided into
the fluid flow channel 38 of the cylinder through the muffler 80 as
indicated by the solid line in FIG. 1. Consequently, introduction
efficiency of the linear compressor is decreased, and thus
performance of the linear compressor is decreased.
SUMMARY OF THE INVENTION
[0022] Therefore, the present invention has been made in view of
the above problems, and it is an object of the present invention to
provide a linear compressor including a muffler the volume of which
is variable as a piston is reciprocated, whereby introduction
efficiency of the linear compressor is improved, and noise
generated at various bands is effectively reduced.
[0023] In accordance with one aspect of the present invention, the
above and other objects can be accomplished by the provision of a
linear compressor comprising: a cylinder provided at one side
thereof with an outlet part; a piston reciprocated in the cylinder
by means of a liner motor for compressing a fluid, the piston
having a fluid flow channel formed therethrough, the fluid flow
channel communicating with the interior of the cylinder; a first
muffler fixedly attached to the rear part of the piston so that the
first muffler is linearly moved along with the piston, the first
muffler having a fluid flow channel formed therein, the fluid flow
channel of the first muffler communicating with the fluid flow
channel of the piston, the first muffler also having a
noise-reducing space defined therein; and a second muffler fixedly
mounted in the compressor such that the inner volume of the second
muffler is variable as the first muffler is linearly moved, the
second muffler having a fluid flow channel formed therein, the
fluid flow channel of the second muffler communicating with the
fluid flow channel of the first muffler, the second muffler also
having a noise-reducing space defined therein.
[0024] Preferably, the first muffler is constructed so that the
rear part of the first muffler is reciprocated while being inserted
in the second muffler.
[0025] Preferably, the gap distance between the outer
circumferential surface of the first muffler and the inner
circumferential surface of the second muffler is 0.1 to 1.0 mm.
[0026] Preferably, the first muffler is formed in the shape of a
cylinder having fluid flow holes formed through the front and rear
parts thereof, respectively, so that the fluid passes through the
fluid flow holes.
[0027] Preferably, the second muffler is formed in the shape of a
cylinder, the cylinder being opened at the front part thereof so
that the first muffler is inserted into the second muffler, the
cylinder having an inlet hole formed therethrough so that the fluid
is introduced through the inlet hole.
[0028] Preferably, the first muffler is provided with a Helmholtz
resonator, and the Helmholtz resonator has a space formed at the
inner circumference of the first muffler in the circumferential
direction.
[0029] Preferably, at least one of the first muffler and the second
muffler has a collection space internally formed at the rear part
thereof.
[0030] Preferably, the collection space is formed in the vicinity
of an inlet pipe where the hole of the first muffler or the second
muffler is extended toward the interior of the muffler. The inlet
pipe is gradually expanded toward the rear part thereof.
[0031] Preferably, the compressor further comprises a back cover
fixed to the rear part of the linear motor, the back cover having
an opening formed at the center part thereof, wherein the second
muffler is fixedly fitted in the opening of the back cover.
[0032] Preferably, at least one of the first and second mufflers is
made of a non-magnetic material.
[0033] The present invention provides a linear compressor having a
muffler, the inner volume of which is variable as a piston is
reciprocated. Consequently, the present invention has an effect of
interrupting noise generated at various bands in the variable space
of the muffler with the result that the high-frequency component of
the noise is effectively reduced.
[0034] Also, the linear compressor according to the present
invention includes an inlet channel, which comprises a first
muffler and a second muffler, formed between a back cover and a
piston. Consequently, leakage of a fluid from the first and second
mufflers, the piston, and the cylinder is minimized. Furthermore,
the second muffler serves to pump the fluid as the volume of the
second muffler is varied, whereby the amount of the fluid
introduced into the cylinder is increased, and thus introduction
efficiency of the linear compressor is improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0036] FIG. 1 is a longitudinal sectional view showing a
conventional linear compressor;
[0037] FIG. 2 is a longitudinal sectional view showing a linear
compressor according to a preferred embodiment of the present
invention;
[0038] FIG. 3 is a sectional view of the linear compressor
according to the preferred embodiment of the present invention
showing the operation of the linear compressor when a piston is
moved forward;
[0039] FIG. 4 is a sectional view of the linear compressor
according to the preferred embodiment of the present invention
showing the operation of the linear compressor when a piston is
moved backward;
[0040] FIG. 5 is a sectional view of a linear compressor according
to another preferred embodiment of the present invention showing
main components of the linear compressor; and
[0041] FIG. 6 is a sectional view of a linear compressor according
to still another preferred embodiment of the present invention
showing main components of the linear compressor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] Now, preferred embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[0043] It should be understood that linear compressors according to
numerous preferred embodiments of the present invention may be
proposed, although only the most preferred embodiments of the
present invention will be hereinafter described.
[0044] FIG. 2 is a longitudinal sectional view showing a linear
compressor according to a preferred embodiment of the present
invention.
[0045] As shown in FIG. 2, the linear compressor according to the
present invention includes: a hermetically sealed container 104
comprising a lower container 101 and an upper cover 104; a cylinder
block 110 placed on a first damper 106 mounted to one side of the
hermetically sealed container 104 in such a manner that shock
applied to the cylinder block 110 is absorbed by means of the first
damper 106, the cylinder block 110 having a cylinder 109 formed
therein; a back cover 120 placed on a second damper 108 mounted to
the other side of the hermetically sealed container 104 in such a
manner that shock applied to the back cover 120 is absorbed by
means of the second damper 108, the back cover 120 being spaced
apart from the cylinder 109 and the cylinder block 110; a linear
motor 130 fixedly disposed between the cylinder block 110 and the
back cover 120 for generating a driving force, which is required to
compress the fluid; a piston 144 connected to the linear motor 130
so that the fluid in the cylinder 109 is compressed by means of the
piston 144 as the piston 144 is reciprocated in the cylinder 109,
the piston 144 having a fluid flow channel 140 formed therein,
through which the fluid is introduced into the cylinder 109, the
piston 144 being provided with an inlet valve 142 for opening and
closing the fluid flow channel 140; an outlet valve 150 for opening
and closing the outlet of the cylinder 109, the outlet valve 150
defining a compression chamber C together with the cylinder 109 and
the piston 144; a first muffler 160 attached to the piston 144, the
first muffler 160 having a communication hole 160a formed therein,
the communication hole 160a communicating with the fluid flow
channel 140 of the piston 144, the first muffler 160 having an
inlet hole 160b, through which the fluid is introduced, the first
muffler 160 also having a noise-reducing space defined therein; and
a second muffler 170 attached to the back cover 120 is such a
manner that the inner volume of the second muffler 170 is variable
as the first muffler 160 is moved forward/backward, the second
muffler 170 having an inlet hole 170a communicating to the outside
of the back cover 120 so that a fluid outside the back cover 120 is
introduced through the inlet hole 170a.
[0046] To the rear part of the hermetically sealed container 104 is
connected an inlet connection pipe 104a in such a manner that the
inlet connection pipe 104a is penetrated into the hermetically
sealed container 104. Below the inlet connection pipe 104a is
disposed an outlet connection pipe 104b for discharging the
compressed fluid in such a manner that the outlet connection pipe
104b is also penetrated into the hermetically sealed container
104.
[0047] The back cover 120 is provided with an opening 120a, in
which the second muffler 170 is fitted, so that the fluid in the
hermetically sealed container 104 is directly introduced into the
second muffler 170 through the inlet hole 170a.
[0048] The opening 120a of the back cover 120 is formed such that
the opening 120a is placed at the same level as the centers of the
piston 144 and the first muffler 160. Preferably, the inner
diameter of the opening 120a of the back cover 120 is equal to or
slightly larger than the outer diameter of the first muffler 160 so
that the first muffler 160 is inserted in the opening 120a of the
back cover 120.
[0049] The linear motor 130 comprises a stator S and a mover M. The
stator S comprises: an outer laminated core 131; an inner laminated
core 132 disposed such that the inner core 132 is spaced apart from
the outer core 131 by a prescribed gap distance; and a coil 133
wound on the outer core 131. The mover M comprises: a magnet 134
moving forward/backward by means of a magnetic force generated
around the coil 133; and a magnet frame 136 disposed between the
outer core 131 and the inner core 132 such that the magnet frame
136 moves forward/backward. The magnet 134 is fixed to the magnet
frame 136. The magnet frame 136 is fixedly attached to the piston
144.
[0050] The outer core 131 is disposed between the cylinder block
110 and the back cover 120 while the outer core 131 is fixed to the
cylinder block 110 and the back cover 120 by means of suitable
fastening members. The inner core 132 is fixed to the cylinder
block 110 by means of suitable fastening members. The magnet frame
136 is fixed to the piston 144 by means of suitable fastening
members.
[0051] A portion of the piston 144 is inserted into the cylinder
109 while being reciprocated in the cylinder 109 so that the piston
144 moves forward and backward in the cylinder 109. To one side of
the piston 144, which is inserted in the cylinder 109, is fixed the
inlet valve 142, and at the other side of the piston 144, which is
not inserted in the cylinder 109, is formed a fixing part 146
protruded in the radial direction. The fixing part 146 of the
piston 144 is fixed to the magnet frame 136 by means of suitable
fastening members.
[0052] The piston 144 is elastically supported by means of a first
spring 144a disposed between one surface of the fixing part 146 and
the cylinder block 110 and a second spring 144b disposed between
the other surface of the fixing part 146 and the back cover 120 so
that the piston 144 is reciprocated along with the mover M of the
linear motor 130 and the first muffler 160.
[0053] Preferably, the inlet valve 142 may be a plate valve wherein
one side of the plate valve is fixed to the piston 144, and the
part of the plate valve corresponding to the fluid flow channel 140
of the piston 144 is elastically bent.
[0054] The outlet valve 150 comprises: an inner outlet cover 152
mounted to the cylinder block 110 while communicating with the
first cylinder 109 and having a fluid outlet hole 151 formed at one
side thereof; an outer outlet cover 154 disposed outside the inner
outlet cover 152 while being spaced apart from the inner outlet
cover 152, the outer outlet cover 154 being connected to a fluid
outlet pipe 153 for discharging the fluid at one side thereof; and
a valve body 158 elastically supported by means of a spring 156
disposed in the inner outlet cover 152 for opening or closing the
first cylinder 109 as the valve body 158 makes contact with or
withdraws from the end of the cylinder 109.
[0055] It is preferable that at least one of the first and second
mufflers 160 and 170 is made of a non-magnetic material so that
decrease of compression efficiency of the linear compressor is
prevented.
[0056] Specifically, the linear motor 130 includes the coil 133 and
the magnet 134, thereby generating a strong magnetic force. Most of
components constituting the linear compressor are generally made of
steel materials. If both of the first muffler 160 and the second
muffler 170 are made of magnetic materials, the magnetic force
generated by means of the linear motor 130 is transmitted to the
second muffler 170 and the back cover 120 via the fist muffler 160.
As a result, an electromagnetic loss is incurred. Furthermore, the
forward/backward movement of the first muffler 160 is not smoothly
carried out due to the magnetic force of the first muffler 160 and
the second muffler 170.
[0057] The first muffler 160 is formed in the shape of a cylinder
having a noise-reducing resonance space defined therein. The first
muffler 160 is provided at the center part of one surface thereof,
which is attached to the piston 144, with the communication hole
160a. The first muffler 160 is also provided at the center part of
the other surface thereof, which is moved into the second muffler
170, with the inlet hole 160b.
[0058] The second muffler 170 is formed in the shape of a cylinder
having a resonance space defined therein. The front part of the
second muffler 170 is opened so that the rear part of the first
muffler 160 is inserted into the second muffler 170. The second
muffler 170 is provided at the center part of the rear surface
thereof with the inlet hole 170a. The resonance space of the second
muffler 170 is variable by means of the first muffler 160, whereby
noise generated at various bands is effectively reduced.
[0059] Reference numeral 200 indicates a loop pipe having one end
connected to the fluid outlet pipe 153 and the other end connected
to the outlet connection pipe 104b.
[0060] FIG. 3 is a sectional view of the linear compressor
according to the preferred embodiment of the present invention
showing the operation of the linear compressor when a piston is
moved forward, and FIG. 4 is a sectional view of the linear
compressor according to the preferred embodiment of the present
invention showing the operation of the linear compressor when a
piston is moved backward.
[0061] The first muffler 160 includes at least one high frequency
noise-reducing expansion chamber 162 or at least one low frequency
noise-reducing Helmholtz resonator 164.
[0062] The expansion chamber 162 is formed at the inner front part
of the first muffler 160 such that the expansion chamber 162 is
extended in the longitudinal direction.
[0063] The Helmholtz resonator 164 is formed such that the
Helmholtz resonator 164 has a space formed at the inner rear part
of the first muffler 160 in the circumferential direction. The
space of the Helmholtz resonator 164 communicates with the interior
of the first muffler 160 through communication holes 163.
[0064] The second muffler 170 comprises: a rear part 172 disposed
at the opening 120a of the back cover 120, the rear part 172 having
the inlet hole 170a formed therethrough; and a cylindrical part 180
extended forward from the edge of the rear part 172 such that the
cylindrical part 180 partially surrounds the circumference of the
first muffler 160 to prevent leakage of the fluid.
[0065] Preferably, the gap distance t between the cylindrical part
180 partially surrounding the circumference of the first muffler
160, and the circumference of the first muffler 160 is 0.1 to 1.0
mm.
[0066] Specifically, it is preferable to set the gap distance t
between the cylindrical part 180 and the first muffler 160 to 0.1
mm or more considering assembly tolerance of the cylindrical part
180 and the first muffler 160 or the forward/backward movement of
the first muffler 160. If the gap distance t is too large, however,
fluid leakage is increased. Therefore, it is preferable that the
gap distance t be limited to 1.0 mm or less.
[0067] The operation of the linear compressor with the above-stated
construction according to the present invention will now be
described in detail.
[0068] When electric current is supplied to the coil 133 of the
linear motor 130, there is created a magnetic field around the coil
133, and the magnet 134 is moved forward and backward due to the
magnetic field created around the coil 133. The forward/backward
movement of the magnet 134 is transmitted to the piston 144 and the
first muffler 160 via the magnet frame 136.
[0069] The piston 144 is moved forward and backward in the cylinder
109 so that the interior of the compression chamber C is compressed
by means of the first piston 144. The first muffler 160 is moved
forward and backward in the second muffler 170 so that the inner
volume of the second muffler 170 is varied by means of the first
muffler 160. As the inner volume of the second muffler 170 is
varied by means of the first muffler 160, noise generated at
various bands is effectively reduced.
[0070] The inlet valve 142 and the outlet valve 150 are opened and
closed due to change of the pressure caused by means of the
forward/backward movement of the piston 144 and the first muffler
160, and the fluid (indicated by a solid line in FIGS. 3 and 4) is
introduced into the hermetically sealed container 104 through the
inlet connection pipe 104a.
[0071] The fluid introduced into the hermetically sealed container
104 is guided to the interior of the second muffler 170 through the
inlet hole 170a of the second muffler 170. At this time, the fluid
is guided along the cylindrical part 10 of the second muffler 170,
whereby leakage of the fluid to the vicinity of the first muffler
160 is maximally prevented. Subsequently, the fluid is introduced
into the first muffler 160 through the inlet hole 160b of the first
muffler 160.
[0072] The fluid introduced into the first muffler 160 passes
through the communication hole 160a of the first muffler 160, the
fluid flow channel 140 of the piston 144, and the inlet valve 142
in turn, and is then introduced into the compression chamber C,
where the fluid is compressed. The compressed fluid is discharged
through the outlet valve 150, the outlet pipe 153, the loop pipe
200, and the outlet connection pipe 104b in turn.
[0073] When the inlet valve and the outlet valve are opened and
closed in the above-mentioned linear compressor according to the
present invention, shock between the inlet valve and the outlet
valve occurs, whereby noise is generated. Such noise is transmitted
to the interior of the first muffler 160 through the fluid flow
channel 140 of the piston 144 and the communication hole 160a of
the first muffler 160.
[0074] The noise transmitted to the interior of the: first muffler
160 passes through the Helmholtz resonator 164 so that the noise
components at the low-frequency bands are interrupted. The noise
components at the high-frequency bands, which have not been
interrupted by means of the first muffler 160, are transmitted to
the interior of the second muffler 170 so that the noise components
at the high-frequency bands are interrupted.
[0075] The noise transmitted to the second muffler 170 is
interrupted by means of the inner space of the second muffler 170.
At this time, noise generated at various bands is effectively
reduced as the inner volume of the second muffler 170 is varied.
Consequently, the amount of the noise transmitted to the outside of
the hermetically sealed container 104 through the second muffler
170 is minimized.
[0076] FIG. 5 is a sectional view of a linear compressor according
to another preferred embodiment of the present invention showing
main components of the linear compressor.
[0077] As shown in FIG. 5, the linear compressor according to the
present invention includes an inlet pipe 174 extended toward the
first muffler 160 so that a collection space for reducing noise is
formed at the rear part 172 of the second muffler 170. The inner
diameter of the inlet pipe 174 is gradually decreased toward the
first muffler 160, in which an inlet hole 170a is defined.
[0078] The first muffler 160 is provided with an inlet pipe 166
having the same or similar shape as the inlet pipe 174 of the
second muffler 170 so that noise is collected by means of the first
muffler 160 while not colliding with or interfering with the inlet
pipe 174 of the second muffler 170. The inlet pipe 166 of the first
muffler 160 has an inlet hole 160b defined therein.
[0079] The linear compressor according to the second preferred
embodiment of the present invention is identical to the compressor
according to the previously described first preferred embodiment of
the present invention in terms of construction and operation except
that the construction of the first muffler and the second muffler
according to the second preferred embodiment of the present
invention is different from that according to the first preferred
embodiment of the present invention. Therefore, elements of the
linear compressor according to the second preferred embodiment of
the present invention, which correspond to those of the linear
compressor according to the first preferred embodiment of the
present invention, are indicated by the same reference numerals as
those of the linear compressor according to the first preferred
embodiment of the present invention, and a detailed description
thereof will not be given.
[0080] The inlet pipe 174 of the second muffler 170 is formed at
the inner center part of the cylindrical part 180 such that the
inlet pipe 174 is spaced apart from the inner circumferential
surface of the cylindrical part 180 of the second muffler 170. The
inlet pipe 174 of the second muffler 170 serves to carry out the
same functions as the inlet part 166 of the first muffler 160.
[0081] Preferably, each of the inlet parts 166 and 174 is formed in
the shape of a funnel, which is increasingly expanded toward the
rear thereof so that the fluid is easily introduced.
[0082] Reference numeral 165 indicates a protruded pipe extended
into the fluid flow channel 140 of the piston 144.
[0083] FIG. 6 is a sectional view of a linear compressor according
to still another preferred embodiment of the present invention
showing main components of the linear compressor.
[0084] In the linear compressor according to the present invention
as shown in FIG. 6, the second muffler 170 is mounted in the back
cover 120, and the back cover 120 has a communication hole 120b,
which communicates with the inlet hole 170a of the second muffler
170, formed therethrough. Other constructions of the linear
compressor according to the third preferred embodiment of the
present invention are identical to those of the linear compressor
according to the previously described first preferred embodiment of
the present invention. Therefore, elements of the linear compressor
according to the third preferred embodiment of the present
invention, which correspond to those of the linear compressor
according to the first preferred embodiment of the present
invention, are indicated by the same reference numerals as those of
the linear compressor according to the first preferred embodiment
of the present invention, and a detailed description thereof will
not be given.
[0085] Preferably, the size of the communication hole 120b of the
back cover 120 is equal to or slightly larger than that of the
inlet hole 170a of the second muffler 170. The fluid existing in
the hermetically sealed container 104 is guided through the
communication hole 120b of the back cover 120 and the inlet hole
170a of the second muffler 170 in turn.
[0086] It should be noted that the present invention is not limited
to the above-mentioned embodiments. For example, the linear
compressor according to the present invention may include a
plurality of first muffler, each of which is moved
forward/backward, and a plurality of second muffler, the inner
volumes of which are variable by means of the first muffler,
respectively.
[0087] As apparent from the above description, the present
invention provides a linear compressor having a muffler, the inner
volume of which is variable as a piston is reciprocated.
Consequently, the present invention has an effect of interrupting
noise generated at various bands in the variable space of the
muffler with the result that high-frequency components of the noise
are effectively reduced.
[0088] Also, the linear compressor according to the present
invention includes an inlet channel, which comprises a first
muffler and a second muffler, formed between a back cover and a
piston. Consequently, fluid leakage from the first and second
mufflers, the piston, and the cylinder is minimized. Furthermore,
the second muffler serves to pump the fluid as the volume of the
second muffler is varied, whereby the amount of the fluid
introduced into the cylinder is increased, and thus introduction
efficiency of the linear compressor is improved.
[0089] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
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