BACKGROUND
1. Field
[0001] A linear compressor and a refrigerator including a linear compressor are disclosed
herein.
2. Background
[0002] In general, compressors are machines that receive power from a power generation device,
such as an electric motor or turbine, to compress air, a refrigerant, or various working
gases, thereby increasing in pressure. Compressors are being widely used in home appliances,
such as refrigerators or air conditioners, or industrial fields.
[0003] Compressors may be largely classified into reciprocating compressors, in which a
compression space into and from which a working gas is suctioned and discharged, is
defined between a piston and a cylinder to allow the piston to be linearly reciprocated
in the cylinder, thereby compressing the working gas; rotary compressors, in which
a compression space into and from which a working gas is suctioned or discharged,
is defined between a roller that eccentrically rotates and a cylinder to allow the
roller to eccentrically rotate along an inner wall of the cylinder, thereby compressing
the working gas; and scroll compressors, in which a compression space into and from
which a working gas is suctioned and discharged, is defined between an orbiting scroll
and a fixed scroll to compress the working gas while the orbiting scroll rotates along
the fixed scroll. In recent years, a linear compressor, which is directly connected
to a drive motor and in which a piston is linearly reciprocated, to improve compression
efficiency without mechanical loss due to movement conversion and having a simple
structure, is being widely developed. The linear compressor may suction and compress
a working gas, such as a refrigerant, while the piston is linearly reciprocated in
a sealed shell by a linear motor and then discharge the working gas.
[0004] The linear motor is configured to allow a permanent magnet to be disposed between
an inner stator and an outer stator. The permanent magnet may be linearly reciprocated
by an electromagnetic force between the permanent magnet and the inner (or outer)
stator. Also, as the permanent magnet operates in a state in which the permanent magnet
is connected to the piston, the refrigerant may suctioned and compressed while the
piston is linearly reciprocated within the cylinder, and then, may be discharged.
[0005] The present Applicant has filed for a patent (hereinafter, referred to as a "prior
art document") and then registered the patent with respect to the linear compressor,
as Korean Patent No.
10-1307688, filed in Korea on September 5, 2013, and entitled "linear compressor", which is
hereby incorporated by reference. The linear compressor according to the prior art
document includes a shell to accommodate a plurality of components. A vertical height
of the shell may be somewhat high, as illustrated in the prior art document. An oil
supply assembly to supply oil between a cylinder and a piston may be disposed within
the shell. When the linear compressor is provided in a refrigerator, the linear compressor
may be disposed in a machine room provided at a rear side of the refrigerator.
[0006] In recent years, a major concern of customers is increasing an inner storage space
of the refrigerator. To increase the inner storage space of the refrigerator, it may
be necessary to reduce a volume of the machine room. To reduce the volume of the machine
room, it may be important to reduce a size of the linear compressor.
[0007] However, as the linear compressor disclosed in the prior art document has a relatively
large volume, the linear compressor in the prior art document is not applicable to
a refrigerator, for which an increase in the inner storage space is sought. To reduce
the size of the linear compressor, it may be necessary to reduce a size of a main
component of the compressor. In this case, the compressor may deteriorate in performance.
[0008] To compensate for the deteriorated performance of the compressor, it may be necessary
to increase a drive frequency. However, the more the drive frequency of the compressor
is increased, the more a friction force due to oil circulating in the compressor is
increased, deteriorating performance of the compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Embodiments will be described in detail with reference to the following drawings
in which like reference numerals refer to like elements, and wherein:
Fig. 1 is a schematic diagram of a refrigerator according to an embodiment;
Fig. 2 is a cross-sectional view of a dryer of the refrigerator of Fig. 1;
Fig. 3 is a cross-sectional view of a linear compressor of the refrigerator of Fig.
1;
Fig. 4 is a cross-sectional view of a suction muffler of the linear compressor of
Fig. 3;
Fig. 5 is a view illustrating a state in which a first filter is coupled to the suction
muffler of Fig. 4;
Fig. 6 is a partial cross-sectional view illustrating a position of a second filter
according to an embodiment;
Fig. 7 is an exploded perspective view of a cylinder and a frame of the linear compressor
of Fig. 3;
Fig. 8 is an exploded perspective of the frame of Fig. 7;
Fig. 9 is a cross-sectional view illustrating a state in which the cylinder and a
piston are coupled to each other according to an embodiment;
Fig. 10 is a view of the cylinder according to an embodiment;
Fig. 11 is an enlarged cross-sectional view of portion A of Fig. 9;
Fig. 12 is a cross-sectional view illustrating a refrigerant flow in the linear compressor
of Fig. 3; and
Fig. 13 is a cross-sectional view illustrating a position of a second filter according
to another embodiment.
DETAILED DESCRIPTION
[0010] Hereinafter, embodiments will be described with reference to the accompanying drawings.
Embodiments may, however, be embodied in many different forms and should not be construed
as being limited to the embodiments set forth herein; rather, alternate embodiments
falling within the spirit and scope will fully convey the concept to those skilled
in the art.
[0011] Fig. 1 is a schematic diagram of a refrigerator according to an embodiment. Referring
to Fig. 1, a refrigerator 10 according to an embodiment may include a plurality of
devices to drive a refrigeration cycle.
[0012] In detail, the refrigerator 10 may include a compressor 100 to compress a refrigerant,
a condenser 20 to condense the refrigerant compressed in the compressor 100, a dryer
200 to remove moisture, foreign substances, or oil from the refrigerant condensed
in the condenser 20, an expansion device 30 to decompress the refrigerant having passed
through the dryer 200, and an evaporator 40 to evaporate the refrigerant decompressed
in the expansion device 30. The refrigerator 10 may further include a condensation
fan 25 to blow air toward the condenser 20, and an evaporation fan 45 to blow air
toward the evaporator 40.
[0013] The compressor 100 may be a linear compressor in which a piston may be directly connected
to a motor to compress the refrigerant while the piston is linearly reciprocated within
a cylinder. The expansion device 30 may include a capillary tube having a relatively
small diameter.
[0014] A liquid refrigerant condensed in the condenser 20 may be introduced into the dryer
200. A gaseous refrigerant may be partially contained in the liquid refrigerant. A
filter to filter the liquid refrigerant introduced into the dryer 200 may be provided
in the dryer 200. Hereinafter, components of the dryer 200 will be described with
reference to the accompanying drawings.
[0015] Fig. 2 is a cross-sectional view of a dryer of the refrigerator of Fig. 1. Referring
to Fig. 2, the dryer 200 according to an embodiment may include a dryer body 210 to
define a flow space for the refrigerant, a refrigerant inflow 211 disposed on or at
one or a first side of the dryer body 210 to guide introduction of the refrigerant,
and a refrigerant discharge 215 disposed on or at the other or a second side of the
dryer body 210 to guide discharge of the refrigerant. For example, the dryer body
210 may have a long cylindrical shape.
[0016] Dryer filters 220, 230, and 240 may be provided in the dryer body 210. In detail,
the dryer filters 220, 230, and 240 may include a first dryer filter 220 disposed
adjacent to the refrigerant inflow 211, a third dryer filter 240 spaced apart from
the first dryer filter 220 and disposed adjacent to the refrigerant discharge 215,
and a second dryer filter 230 disposed between the first dryer filter 220 and the
third dryer filter 240.
[0017] The first dryer filter 220 may be disposed adjacent to an inside of the refrigerant
inflow 211, that is, disposed at a position closer to the refrigerant inflow 211 than
the refrigerant discharge 215.
[0018] The first dryer filter 220 may have an approximately hemispherical shape. An outer
circumferential surface of the first dryer filter 220 may be coupled to an inner circumferential
surface of the dryer body 210. A plurality of through holes 221 to guide flow of the
refrigerant may be defined in the first dryer filer 220. A foreign substance having
a relatively large volume may be filtered by the first dryer filter 220.
[0019] The second dryer filter 230 may include a plurality of adsorbents 231. Each of the
adsorbents 231 may be a grain having a predetermined size. The adsorbent 231 may be
a molecular sieve and have a predetermined size of about 5 mm to about 10 mm.
[0020] A plurality of holes may be defined in the adsorbent 231. Each of the plurality of
holes may have a size similar to a size of oil (about 10A). The hole may have a size
greater than a size (about 2.8Å to about 3.2A) of the moisture and (about 4.0Å in
case of R134a, and about 4.3Å in the case of R600a) of the refrigerant. The term "oil"
may refer to a working oil or cutting oil injected when components of the refrigeration
cycle are manufactured or processed.
[0021] The refrigerant and moisture passing through the first dryer filter 220 may be easily
discharged even though the refrigerant and moisture are easily introduced into the
plurality of holes while passing through the adsorbents 231. Thus, the refrigerant
and moisture may not be easily adsorbed onto the adsorbents 231. However, if the oil
is introduced into the plurality of holes, the oil may not be easily discharged, and
thus, may be maintained in a state in which the oil is adsorbed onto the adsorbents
231.
[0022] For example, the adsorbent 231 may include a BASF 13X molecular sieve. A hole defined
in the BASF 13X molecular sieve may have a size of about 10Å (1 nm), and the BASF
13X molecular sieve may be expressed as a chemical formula: Na2O · Al2O3 · mSiO2 ·
nH20 (m ≤ 2.35).
[0023] The oil contained in the refrigerant may be adsorbed into the plurality of adsorbents
231 while passing through the second dryer filter 230. Alternatively, the second dryer
filter 230 may include an oil adsorbent paper or an adsorbent having a felt, instead
of the plurality of adsorbents each having a grain shape.
[0024] The third dryer filter 240 may include a coupling portion 241 coupled to the inner
circumferential surface of the dryer body 210, and a mesh 242 that extends from the
coupling portion 241 toward the refrigerant discharge 215. The third dryer filer 240
may be a mesh filter. A foreign substance having a fine size contained in the refrigerant
may be filtered by the mesh 242.
[0025] Each of the first dryer filter 220 and the third dryer filter 240 may serve as a
support to locate the plurality of adsorbents 231 within the dryer body 210. That
is, discharge of the plurality of adsorbents 231 from the dryer 200 may be restricted
by the first and third dryer filters 220 and 240.
[0026] As described above, the filters may be provided in the dryer 200 to remove foreign
substances or oil contained in the refrigerant, thereby improving reliability of the
refrigerant that acts as a gas bearing.
[0027] Fig. 3 is a cross-sectional view of a linear compressor of the refrigerant in Fig.
1. Referring to Fig. 3, the linear compressor 100 according to an embodiment may include
a shell 101 having an approximately cylindrical shape, a first cover 102 coupled to
a first side of the shell 101, and a second cover 103 coupled to a second side of
the shell 101. For example, the linear compressor 100 may be laid out in a horizontal
direction. The first cover 102 may be coupled to a right or first lateral side of
the shell 101, and the second cover 103 may be coupled to a left or second lateral
side of the shell 101 with reference to Fig. 3. Each of the first and second covers
102 and 103 may be understood as one component of the shell 101.
[0028] The linear compressor 100 may further include a cylinder 120 provided in the shell
101, a piston 130 linearly reciprocated within the cylinder 120, and a motor assembly
that serves as a linear motor to apply a drive force to the piston 130. When the motor
assembly 140 operates, the piston 130 may be linearly reciprocated at a high rate.
The linear compressor 100 according to this embodiment may have a drive frequency
of about 100 Hz, for example.
[0029] The linear compressor 100 may include a suction inlet 104, through which the refrigerant
may be introduced, and a discharge outlet 105, through which the refrigerant compressed
in the cylinder 120 may be discharged. The suction inlet 104 may be coupled to the
first cover 102, and the discharge outlet 105 may be coupled to the second cover 103.
[0030] The refrigerant in suctioned through the suction inlet 104 may flow into the piston
130 via a suction muffler 150. Thus, while the refrigerant passes through the suction
muffler 150, noise may be reduced. The suction muffler 150 may include a first muffler
151 coupled to a second muffler 153. At least a portion of the suction muffler 150
may be disposed within the piston 130.
[0031] The piston 130 may include a piston body 131 having an approximately cylindrical
shape, and a piston flange 132 that extends from the piston body 131 in a radial direction.
The piston body 131 may be reciprocated within the cylinder 120, and the piston flange
132 may be reciprocated outside of the cylinder 120.
[0032] The piston 130 may be formed of an aluminum material, such as aluminum or an aluminum
alloy, which is a nonmagnetic material. As the piston 130 may be formed of the aluminum
material, a magnetic flux generated in the motor assembly 140 may not be transmitted
into the piston 130, and thus, may be prevented from leaking outside of the piston
130. The piston 130 may be manufactured by a forging process, for example.
[0033] The cylinder 120 may be formed of an aluminum material, such as aluminum or an aluminum
alloy, which is a nonmagnetic material. The cylinder 120 and the piston 130 may have
a same material composition, that is, a same kind of material and composition.
[0034] As the piston cylinder 120 may be formed of the aluminum material, a magnetic flux
generated in the motor assembly 200 may not be transmitted into the cylinder 120,
and thus, may be prevented from leaking outside of the cylinder 120. The cylinder
120 may be manufactured by an extruding rod processing process, for example.
[0035] Also, as the piston 130 may be formed of the same material as the cylinder 120, the
piston 130 may have a same thermal expansion coefficient as the cylinder 120. When
the linear compressor 100 operates, a high-temperature (a temperature of about 100
°C) environment may be created within the shell 100. Thus, as the piston 130 and the
cylinder 120 may have the same thermal expansion coefficient, the piston 130 and the
cylinder 120 may be thermally deformed by a same degree. As a result, the piston 130
and the cylinder 120 may be thermally deformed with sizes and in directions different
from each other to prevent the piston 130 from interfering with the cylinder 120 while
the piston 130 moves.
[0036] The cylinder 120 may be configured to accommodate at least a portion of the suction
muffler 150 and at least a portion of the piston 130. The cylinder 120 may have a
compression space P, in which the refrigerant may be compressed by the piston 130.
A suction hole 133, through which the refrigerant may be introduced into the compression
space P, may be defined in or at a front portion of the piston 130, and a suction
valve 135 to selectively open the suction hole 133 may be disposed on or at a front
side of the suction hole 133. A coupling hole, to which a predetermined coupling member
may be coupled, may be defined in an approximately central portion of the suction
valve 135.
[0037] A discharge cover 160 that defines a discharge space or discharge passage for the
refrigerant discharged from the compression space P, and a discharge valve assembly
161, 162, and 163 coupled to the discharge cover 160 to selectively discharge the
refrigerant compressed in the compression space P may be provided at a front side
of the compression space P. The discharge valve assembly 161, 162, and 163 may include
a discharge valve 161 to introduce the refrigerant into the discharge space of the
discharge cover 160 when a pressure within the compression space P is above a predetermined
discharge pressure, a valve spring 162 disposed between the discharge valve 161 and
the discharge cover 160 to apply an elastic force in an axial direction, and a stopper
163 to restrict deformation of the valve spring 162.
[0038] The term "compression space P" may be refer to a space defined between the suction
valve 135 and the discharge valve 161. The term "axial direction" may refer a direction
in which the piston 130 may be reciprocated, that is, a transverse direction in Fig.
3. Also, in the axial direction, a direction from the suction inlet 104 toward the
discharge outlet 105, that is, a direction in which the refrigerant flows, may be
referred to as a "frontward direction", and a direction opposite to the frontward
direction may be referred to as a "rearward direction". On the other hand, the term
"radial direction" may refer to a direction perpendicular to the direction in which
the piston 130 is reciprocated, that is, a vertical direction in Fig. 3.
[0039] The stopper 163 may be seated on the discharge cover 160, and the valve spring 162
may be seated at a rear side of the stopper 163. The discharge valve 161 may be coupled
to the valve spring 162, and a rear portion or rear surface of the discharge valve
161 may be supported by a front surface of the cylinder 120. The valve spring 162
may include a plate spring, for example.
[0040] The suction valve 135 may be disposed on or at a first side of the compression space
P, and the discharge valve 161 maybe disposed on or at a second side of the compression
space P, that is, a side opposite of the suction valve 135.
[0041] While the piston 130 is linearly reciprocated within the cylinder 120, when the pressure
of the compression space P is below the predetermined discharge pressure and a predetermined
suction pressure, the suction valve 135 may be opened to suction the refrigerant into
the compression space P. On the other hand, when the pressure of the compression space
P is above the predetermined suction pressure, the refrigerant may be compressed in
the compression space P in a state in which the suction valve 135 is closed.
[0042] When the pressure of the compression space P is above the predetermined discharge
pressure, the valve spring 162 may be deformed to open the discharge valve 161. The
refrigerant may be discharged from the compression space P into the discharge space
of the discharge cover 160.
[0043] The refrigerant flowing into the discharge space of the discharge cover 160 may be
introduced into a loop pipe 165. The loop pipe 165 may be coupled to the discharge
cover 160 to extend to the discharge outlet 105, thereby guiding the compressed refrigerant
in the discharge space into the discharge outlet 105. For example, the loop pipe 165
may have a shape which is wound in a predetermined direction and extends in a rounded
shape. The loop pipe 165 may be coupled to the discharge outlet 105.
[0044] The linear compressor 100 may further include a frame 110. The frame 110 may fix
the cylinder 120 and be coupled to the cylinder 120 by a separate coupling member,
for example. The frame 110 may be disposed to surround the cylinder 120. That is,
the cylinder 120 may be accommodated within the frame 110. The discharge cover 172
may be coupled to a front surface of the frame 110.
[0045] At least a portion of the high-pressure gaseous refrigerant discharged through the
open discharge valve 161 may flow toward an outer circumferential surface of the cylinder
120 through a space formed at a portion at which the cylinder 120 and the frame 110
are coupled to each other. The refrigerant may be introduced into the cylinder 120
through one or more gas inflow (see reference numeral 122 of Fig. 7) and one or more
nozzle (see reference numeral 123 of Fig. 11), which may be defined in the cylinder
120. The introduced refrigerant may flow into a space defined between the piston 130
and the cylinder 120 to allow an outer circumferential surface of the piston 130 to
be spaced apart from an inner circumferential surface of the cylinder 120. Thus, the
introduced refrigerant may serve as a "gas bearing" that reduces friction between
the piston 130 and the cylinder 120 while the piston 130 is reciprocated.
[0046] The motor assembly 140 may include outer stators 141, 143, and 145 fixed to the frame
110 and disposed to surround the cylinder 120, an inner stator 148 disposed to be
spaced inward from the outer stators 141, 143, and 145, and a permanent magnet 146
disposed in a space between the outer stators 141, 143, and 145 and the inner stator
148. The permanent magnet 146 may be linearly reciprocated by a mutual electromagnetic
force between the outer stators 141, 143, and 145 and the inner stator 148. Also,
the permanent magnet 146 may be a single magnet having one polarity, or a plurality
of magnets having three polarities.
[0047] The permanent magnet 146 may be coupled to the piston 130 by a connection member
138. In detail, the connection member 138 may be coupled to the piston flange 132
and be bent to extend toward the permanent magnet 146. As the permanent magnet 146
is reciprocated, the piston 130 may be reciprocated together with the permanent magnet
146 in the axial direction.
[0048] The motor assembly 140 may further include a fixing member 147 to fix the permanent
magnet 146 to the connection member 138. The fixing member 147 may be formed of a
composition in which glass fiber or carbon fiber is mixed with a resin. The fixing
member 147 may surround an outside of the permanent magnet 146 to firmly maintain
a coupled state between the permanent magnet 146 and the connection member 138.
[0049] The outer stators 141, 143, and 145 may include coil winding bodies 143 and 145,
and a stator core 141. The coil winding bodies 143 and 145 may include a bobbin 143,
and a coil 145 wound in a circumferential direction of the bobbin 145. The coil 145
may have a polygonal cross-section, for example, a hexagonal cross-section. The stator
core 141 may be manufactured by stacking a plurality of laminations in the circumferential
direction and be disposed to surround the coil winding bodies 143 and 145.
[0050] A stator cover 149 may be disposed on or at one side of the outer stators 141, 143,
and 145. A first side of the outer stators 141, 143, and 145 may be supported by the
frame 110, and a second side of the outer stators 141, 143, and 145 may be supported
by the stator cover 149. The inner stator 148 may be fixed to a circumference of the
frame 110. In the inner stator 148, a plurality of laminations may be stacked in the
circumferential direction outside of the cylinder 120.
[0051] The linear compressor 100 may further include a support 137 to support the piston
130, and a back cover 170 spring-coupled to the support 137. The support 137 may be
coupled to the piston flange 132 and the connection member 138 by a predetermined
coupling member, for example.
[0052] A suction guide 155 may be coupled to a front portion of the back cover 170. The
suction guide 155 may guide the refrigerant suctioned in through the suction inlet
104 to introduce the refrigerant into the suction muffler 150.
[0053] The linear compressor 100 may further include a plurality of springs 176 which are
adjustable in natural frequency to allow the piston 130 to perform a resonant motion.
The plurality of springs 176 may include a first spring supported between the support
137 and the stator cover 149, and a second spring supported between the support 137
and the back cover 170.
[0054] The linear compressor 100 may additionally further include plate springs 172 and
174, respectively, disposed on both sides of the shell 101 to allow inner components
of the compressor 100 to be supported by the shell 101. The plate springs 172 and
174 may include a first plate spring 172 coupled to the first cover 102, and a second
plate spring 174 coupled to the second cover 103. For example, the first plate spring
172 may be fitted into a portion at which the shell 101 and the first cover 102 are
coupled to each other, and the second plate spring 174 may be fitted into a portion
at which the shell 101 and the second cover 103 are coupled to each other.
[0055] Fig. 4 is a cross-sectional view of a suction muffler of the linear compressor of
Fig. 1. Fig. 5 is a view illustrating a state in which a first filter is coupled to
the suction muffler of Fig. 4.
[0056] Referring to Figs. 4 and 5, the suction muffler 150 according to this embodiment
may include the first muffler 151, the second muffler 153 coupled to the first muffler
151, and a first filter 310 supported by the first and second mufflers 151 and 153.
A flow space, in which the refrigerant may flow, may be defined in each of the first
and second mufflers 151 and 153. The first muffler 151 may extend from an inside of
the suction inlet 104 in a direction of the discharge outlet 105, and at least a portion
of the first muffler 151 may extend inside of the suction guide 155. The second muffler
153 may extend from the first muffler 151 inside of the piston body 131.
[0057] The first filter 310 may be disposed in the flow space to filter foreign substances.
The first filter 310 may be formed of a material having a magnetic property. Thus,
foreign substances contained in the refrigerant, in particular, metallic substances,
may be easily filtered.
[0058] For example, the first filter 310 may be formed of stainless steel, and thus, may
have a magnetic property to prevent the first filter 310 from rusting. Alternatively,
the first filter 310 may be coated with a magnetic material, or a magnet may be attached
to a surface of the first filter 310.
[0059] The first filter 310 may be provided as a mesh-type structure having a plurality
of filter holes and have an approximately circular plate shape. Each of the filter
holes may have a diameter or width less than a predetermined diameter or width, that
is, a predetermined size. For example, the predetermined size may be about 25 µm.
[0060] The first muffler 151 and the second muffler 153 may be assembled with each other
using a press-fit manner, for example. The first filter 310 may be fitted into a portion
into which the first and second mufflers 151 and 153 are press-fitted and then be
assembled. In detail, a groove 151a, to which at least a portion of the second muffler
153 may be coupled, may be defined in the first muffler 151. The second muffler 153
may include a protrusion 153a inserted into the groove 151 a of the first muffler
151.
[0061] The first filter 310 may be supported by the first and second mufflers 151 and 153
in a state in which both sides of the first filter 310 are disposed between the groove
151a and the protrusion 153a. In the state in which the first filter 310 is disposed
between the first and second mufflers 151 and 153, when the first and second mufflers
151 and 153 move in a direction that approach each other and then are press-fitted,
both sides of the first filter 310 may be inserted and fixed between the groove 151
a and the protrusion 153a.
[0062] As described above, as the first filter 310 may be provided on the suction muffler
150, a foreign substance having a size greater than a predetermined size of the refrigerant
suctioned in through the suction inlet 104 may be filtered by the first filter 310.
Thus, the first filter 310 may filter the foreign substance from the refrigerant acting
as the gas bearing between the piston 130 and the cylinder 120 to prevent the foreign
substance from being introduced into the cylinder 120. Also, as the first filter 310
is firmly fixed to the portion at which the first and second mufflers 151 and 153
are coupled or press-fitted, separation of the first filter 310 from the suction muffler
150 may be prevented.
[0063] In this embodiment, although the groove 151 a is defined in the first muffler 151,
and the protrusion 153a is disposed on the second muffler 153, embodiments are not
limited thereto. For example, the protrusion 153a may be disposed on the first muffler
151, and the groove 151a may be defined in the second muffler 153.
[0064] Fig. 6 is a partial cross-sectional view illustrating a position of a second filter
according to an embodiment. Fig. 7 is an exploded perspective view of a cylinder and
a frame of the linear compressor of Fig. 3. Fig. 8 is an exploded perspective of the
frame of Fig. 7.
[0065] Referring to Figs. 6 to 8, the linear compressor 100 according to an embodiment may
include a second filter 320 disposed between the frame 110 and the cylinder 120 to
filter a high-pressure gas refrigerant discharged through the discharge valve 161.
The second filter 320 may be disposed on or at a portion of a coupled surface at which
the frame 110 and the cylinder 120 are coupled to each other.
[0066] In detail, the cylinder 120 may include a cylinder body 121 having an approximately
cylindrical shape, and a cylinder flange 125 that extends from the cylinder body 121
in a radial direction. The cylinder body 121 may include at least one gas inflow 122,
through which the discharged gas refrigerant may be introduced. The gas inflow 122
may be formed in a circular shape along a circumferential surface of the cylinder
body 121.
[0067] The at least one gas inflow 122 may include a plurality of gas inflows 122. The plurality
of gas inflows 122 may include gas inflows (see reference numerals 122a and 122b of
Fig. 10) disposed on a first side with respect to a center or central portion 121c
of the cylinder body 121 in an axial direction, and a gas inflow (see reference numeral
122c of Fig. 10) disposed on a second side with respect to the center or central portion
121c of the cylinder body 121 in the axial direction.
[0068] One or more coupling portion 126 coupled to the frame 110 may be disposed on the
cylinder flange 125. Each coupling portion 126 may protrude outward from an outer
circumferential surface of the cylinder flange 125, and be coupled to a cylinder coupling
hole 118 of the frame 110 by a predetermined coupling member, for example.
[0069] The cylinder flange 125 may have a seat surface 127 seated on the frame 110. The
seat surface 127 may be a rear surface of the cylinder flange 125 that extends from
the cylinder body 121 in a radial direction.
[0070] The frame 110 may include a frame body 111 that surrounds the cylinder body 121,
and a cover coupling portion 115 that extends in a radial direction of the frame body
and is coupled to the discharge cover 160.
[0071] The cover coupling portion 115 may have a plurality of cover coupling holes 116,
in which the coupling member coupled to the discharge cover 160 may be inserted, and
a plurality of the cylinder coupling holes 118, in which the coupling member coupled
to the cylinder flange 125 may be inserted. The plurality of cylinder coupling holes
118 may be defined at positions recessed somewhat from the cover coupling portion
115.
[0072] The frame 110 may have a recess 117 recessed backward from the cover coupling portion
115 to allow the cylinder flange 125 to be inserted therein. That is, the recess 117
may be disposed to surround the outer circumferential surface of the cylinder flange
125. The recess 117 may have a recessed depth corresponding to a front to rear width
of the cylinder flange 125.
[0073] A predetermined refrigerant flow space may be defined between an inner circumferential
surface of the recess 117 and the outer circumferential surface of the cylinder flange
125. The high-pressure gas refrigerant discharged from the discharge valve 161 may
flow toward the outer circumferential surface of the cylinder body 121 via the refrigerant
flow space. The second filter 320 may be disposed in the refrigerant flow space to
filter the refrigerant.
[0074] In detail, a seat 113 having a stepped portion maybe disposed on or at a rear end
of the recess 117. The second filter 320 having a ring shape may be seated on the
seat 113.
[0075] In a state in which the second filter 320 is seated on the seat 113, when the cylinder
120 is coupled to the frame 110, the cylinder flange 125 may push the second filter
320 from a front side of the second filter 320. That is, the second filter 320 may
be disposed and fixed between the seat 113 of the frame 110 and the seat surface 127
of the cylinder flange 125.
[0076] The second filter 320 may prevent foreign substances in the high-pressure gas refrigerant
discharged through the opened discharge valve 161 from being introduced into the gas
inflow 122 of the cylinder 120 and be configured to adsorb oil contained in the refrigerant
thereon. For example, the second filter 320 may include a felt formed of polyethylene
terephthalate (PET) fiber or an adsorbent paper. The PET fiber may have superior heat-resistance
and mechanical strength. Also, a foreign substance having a size of about 2 µm or
more, which is contained in the refrigerant, may be blocked.
[0077] The high-pressure gas refrigerant passing through the flow space defined between
the inner circumferential surface of the recess 117 and the outer circumferential
surface of the cylinder flange 125 may pass through the second filter 320. In this
process, the refrigerant may be filtered by the second filter 320.
[0078] Fig. 9 is a cross-sectional view illustrating a state in which the cylinder and a
piston are coupled to each other according to an embodiment. Fig. 10 is a view of
the cylinder according to an embodiment. Fig. 11 is an enlarged cross-sectional view
of portion A of Fig. 9.
[0079] Referring to Figs. 9 to 11, the cylinder 120 according to an embodiment may include
the cylinder body 121 having an approximately cylindrical shape to form a first body
end 121 a and a second body end 121b, and the cylinder flange 125 that extends from
the second body end 121b of the cylinder body 121 in a radial direction. The first
body end 121 a and the second body end 121 b form both ends of the cylinder body 121
with respect to the central portion 121c of the cylinder body 121 in an axial direction.
[0080] The cylinder body 121 may include a plurality of the gas inflows 122, through which
at least a portion of the high-pressure gas refrigerant discharged through the discharge
valve 161 may flow. A third filter 330 may be disposed in the plurality of gas inflows
122.
[0081] Each of the plurality of gas inflows 122 may be recessed from the outer circumferential
surface of the cylinder body 121 by a predetermined depth and width. The refrigerant
may be introduced into the cylinder body 121 through the plurality of gas inflows
122 and the nozzle 123.
[0082] The introduced refrigerant may be disposed between the outer circumferential surface
of the piston 130 and the inner circumferential surface of the cylinder 120 to serve
as the gas bearing with respect to movement of the piston 130. That is, the outer
circumferential surface of the piston 130 may be maintained in a state in which the
outer circumferential surface of the piston 130 is spaced apart from the inner circumferential
surface of the cylinder 120 by pressure of the refrigerant.
[0083] The plurality of gas inflows 122 may include first and second gas inflows 122a and
122b disposed on a first side with respect to the central portion 121c in an axial
direction of the cylinder body 121, and a third gas inflow 122c disposed on a second
side with respect to the central portion 121c in the axial direction. The first and
second gas inflows 122a and 122b may be disposed at positions closer to the second
body end 121b with respect to the central portion 121c in the axial direction of the
cylinder body 121, and the third gas inflow 122c may be disposed at a position closer
to the first body end 121a with respect to the central portion 121c in the axial direction
of the cylinder body 121. That is, the plurality of gas inflows 122 may be provided
in numbers which are not symmetrical to each other with respect to the central portion
121c in the axial direction of the cylinder body 121.
[0084] Referring to Fig. 10, the cylinder 120 may have a relatively high inner pressure
at a side of the second body end 121 b, which may be closer to a discharge-side of
the compressed refrigerant when compared to that of the first body end 121 a, which
may be closer to a suction-side of the refrigerant. Thus, more gas inflows 122 may
be provided at the side of the second body end 121 b to enhance a function of the
gas bearing, and relatively less gas inflows 122 may be provided at the side of the
first body end 121 a.
[0085] The cylinder body 121 may further include one or more nozzle 123 that extends from
the plurality of gas inflows 122 toward the inner circumferential surface of the cylinder
body 121. Each nozzle 123 may have a width or size less than a width or size of the
gas inflow 122.
[0086] A plurality of the nozzles 123 may be provided along the gas inflow 122, which may
extend in a circular shape. The plurality of nozzles 123 may be disposed to be spaced
apart from each other.
[0087] The plurality of nozzles 123 may each include an inlet 123a connected to the gas
inflow 122, and an outlet 123b connected to the inner circumferential surface of the
cylinder body 121. Each nozzle 123 may have a predetermined length from the inlet
123a toward the outlet 123b.
[0088] A recessed depth and width of each of the plurality of gas inflows 122 and a length
of the nozzle 123 may be determined to have adequate dimensions in consideration of
a rigidity of the cylinder 120, an amount of third filter 330, or a intensity in pressure
drop of the refrigerant passing through the nozzle 123. For example, if the recessed
depth and width of each of the plurality of gas inflows 122 are too large, or the
length of the nozzle 123 is too short, rigidity of the cylinder 120 may be weak. On
the other hand, if the recessed depth and width of each of the plurality of gas inflows
122 are too small, an amount of third filter 330 provided in the gas inflow 122 may
be too small. Also, if the length of the nozzle 123 is too long, a pressure drop of
the refrigerant passing through the nozzle 123 may be too large, and it may be difficult
to perform the function as the gas bearing.
[0089] The inlet 123a of the nozzle 123 may have a diameter greater than a diameter of the
outlet 123b. In detail, if the diameter of the nozzle 123 is too small, an amount
of refrigerant, which may be introduced from the nozzle 123, of the high-pressure
gas refrigerant discharged through the discharge valve 161 may be too large, increasing
flow loss in the compressor. On the other hand, if the diameter of the nozzle 123
is too small, the pressure drop in the nozzle 123 may increase, reducing a performance
of the gas bearing.
[0090] Thus, in this embodiment, the inlet 123a of the nozzle 123 may have a relatively
large diameter to reduce the pressure drop of the refrigerant introduced into the
nozzle 123. In addition, the outlet 123b may have a relatively small diameter to control
an inflow amount of gas bearing through the nozzle 123 to a predetermined value or
less.
[0091] The third filter 330 may prevent a foreign substance having a predetermined size
or more from being introduced into the cylinder 120 and perform a function of adsorbing
oil contained in the refrigerant. The predetermined size may be about 1 µm.
[0092] The third filter 330 may include a thread which is wound around the gas inflow 122.
In detail, the thread may be formed of a polyethylene terephthalate (PET) material
and have a predetermined thickness or diameter.
[0093] The thickness or diameter of the thread may be determined to have adequate dimensions
in consideration of a rigidity of the thread. If the thickness or diameter of the
thread is too small, the thread may be easily broken due to a very weak strength thereof.
On the other hand, if the thickness or diameter of the thread is too large, a filtering
effect with respect to foreign substances may be deteriorated due to a very large
pore in the gas inflow 122 when the thread is wound.
[0094] For example, the thickness or diameter of the thread maybe several hundreds µm. The
thread may be manufactured by coupling a plurality of strands of a spun thread having
several tens µm to each other, for example.
[0095] The thread may be wound several times, and an end of the thread may be fixed with
a knot, for example. A number of windings of the thread may be adequately selected
in consideration of the pressure drop of the gas refrigerant and the filtering effect
with respect to foreign substances. If the number of thread windings is too large,
the pressure drop of the gas refrigerant may increase. On the other hand, if the number
of thread windings is too small, the filtering effect with respect to foreign substances
may be reduced.
[0096] Also, a tension force of the wound thread may be adequately controlled in consideration
of deformation of the cylinder and fixation of the thread. If the tension force is
too large, deformation of the cylinder 120 may occur. On the other hand, if the tension
force is too small, the thread may not be adequately fixed to the gas inflow 122.
[0097] Fig. 12 is a cross-sectional view illustrating a refrigerant flow in the linear compressor
of Fig. 3. Referring to Fig. 12, refrigerant flow in the linear compressor according
to an embodiment will be described hereinbelow.
[0098] Referring to Fig. 12, the refrigerant may be introduced into the shell 101 through
the suction inlet 104 and flow into the suction muffler 150 through the suction guide
155. The refrigerant may be introduced into the second muffler 153 via the first muffler
151 of the suction muffler 150 to flow into the piston 130. In this way, suction noise
of the refrigerant may be reduced.
[0099] A foreign substance having a predetermined size (about 25 µm) or more, which is contained
in the refrigerant, may be filtered while passing through the first filter 310 provided
on or in the suction muffler 150. The refrigerant within the piston 130 after passing
though the suction muffler 150 may be suctioned into the compression space P through
the suction hole 133 when the suction valve 135 is opened.
[0100] When the refrigerant pressure in the compression space P is above the predetermined
discharge pressure, the discharge valve 161 may be opened. Thus, the refrigerant may
be discharged into the discharge space of the discharge cover 160 through the opened
discharge valve 161, flow into the discharge outlet 105 through the loop pipe 165
coupled to the discharge cover 160, and be discharged outside of the compressor 100.
[0101] At least a portion of the refrigerant within the discharge space of the discharge
cover 160 may flow toward the outer circumferential surface of the cylinder body 121
via the space defined between the cylinder 120 and the frame 110, that is, the inner
circumferential surface of the recess 117 of the frame 110 and the outer circumferential
surface of the cylinder flange 125 of the cylinder 120. The refrigerant may pass through
the second filter 320 disposed between the seat surface 127 of the cylinder flange
125 and the seat 113 of the frame 110. In this way, a foreign substance having a predetermined
size (about 2 µm) or more may be filtered. Also, oil in the refrigerant may be adsorbed
onto or into the second filter 320.
[0102] The refrigerant passing through the second filter 320 may be introduced into the
plurality of gas inflows 122 defined in the outer circumferential surface of the cylinder
body 121. Also, while the refrigerant passes through the third filter 330 provided
on or in the gas inflows 122, a foreign substances having a predetermined size (about
1 µm) or more, which is contained in the refrigerant, may be filtered, and oil contained
in the refrigerant may be adsorbed.
[0103] The refrigerant passing through the third filter 330 may be introduced into the cylinder
120 through the nozzle 123 and be disposed between the inner circumferential surface
of the cylinder 120 and the outer circumferential surface of the piston 130 to space
the piston 130 from the inner circumferential surface of the cylinder 120 (gas bearing).
As described above, the high-pressure gas refrigerant may be bypassed within the cylinder
120 to serve as the gas bearing with respect to the piston 130 which is reciprocated,
thereby reducing abrasion between the piston 130 and the cylinder 120. Also, as oil
is not used for the bearing, friction loss due to oil may not occur even though the
compressor 100 operates at a high rate.
[0104] Also, as the plurality of filters may be provided on the path or passage of the refrigerant
flowing in the compressor 100, foreign substances contained in the refrigerant may
be removed. Thus, the refrigerant acting as the gas bearing may be improved in reliability.
Thus, it may prevent the piston 130 or the cylinder 120 from being worn by foreign
substances contained in the refrigerant. Also, as the oil contained in the refrigerant
may be removed by the plurality of filters, it may prevent friction loss due to the
oil from occurring.
[0105] The first, second, and third filters 310, 320, and 330 may be referred to as a "filter
device" in that the filters 310, 320, and 330 filter the refrigerant that serves as
the gas bearing. That is, the filter device may include at least one filter member
disposed on or in the "refrigerant passage" from the suction inlet 104 to the nozzle
123 via the discharge valve 161. Thus, foreign substances and oil in the refrigerant
to be introduced into the nozzle 123 may be filtered while passing through the filter
member.
[0106] Hereinafter, another embodiment will be described. This embodiment may be the same
as the previous embodiment except for an arrangement of a second filter, and thus,
different points therebetween will be mainly described, and repetitive disclosure
has been omitted.
[0107] Fig. 13 is a cross-sectional view of illustrating a position of a second filter is
disposed according to another embodiment. Referring to Fig. 13, linear compressor
100 according to this embodiment may include a second filter 420 disposed between
an outer circumferential surface of cylinder flange 125 and an inner circumferential
surface of recess 117 of frame 110.
[0108] The second filter 420 may extend from a front end of the cylinder flange part 125
in an axial direction of the compressor 100. Thus, at least a portion of a refrigerant
discharged through discharge valve 161 may flow backward along a longitudinal direction
of the second filter 420.
[0109] For example, the second filter 420 may include a felt formed of polyethylene terephthalate
(PET) fiber or an adsorbent paper. The PET fiber may have superior heat-resistance
and mechanical strength. Also, a foreign substance having a size of about 2 µm or
more, which may be contained in the refrigerant, may be blocked.
[0110] As the second filter 420 may be disposed in a refrigerant flow space defined between
the cylinder 120 and the frame 110, foreign substances in the refrigerant may be filtered,
and oil contained in the refrigerant may be adsorbed onto or into the second filter
420.
[0111] According to embodiments disclosed herein, a compressor including inner components
may decrease in size to reduce a volume of a machine room of a refrigerator and increase
an inner storage space of the refrigerant. Also, a drive frequency of the compressor
may increase to prevent performance of inner components from being deteriorated due
to the decreasing size thereof. In addition, as the gas bearing may be applied between
the cylinder and the piston, friction force occurring due to oil may be reduced.
[0112] Further, as the plurality of filter devices may be provided in the compressor, foreign
substances or oil contained in the compressed gas (or discharge gas) introduced to
the outside of the piston may be prevented from being introduced into the nozzle of
the cylinder. More particularly, the first filter may be provided on the suction muffler
to prevent the foreign substances contained in the refrigerant from being introduced
into the compression chamber. Also, the second filter may be provided on the coupling
between the cylinder and the frame to prevent the foreign substances and oil contained
in the compressed refrigerant gas from flowing into the gas inflow of the cylinder.
[0113] Also, the third filter may be provided on the gas inflow of the cylinder to prevent
the foreign substances and oil from being introduced into the nozzle of the cylinder
from the gas inflow. Additionally, the filter device may be provided in the dryer
provided in the refrigerator to filter the moisture, foreign substances, or oil contained
in the refrigerant.
[0114] As described above, as foreign substances or oil contained in the compression gas
that acts as a bearing may be filtered through the plurality of filtering devices
provided in the compressor and dryer, it may prevent the nozzle of the cylinder from
being blocked by the foreign substances or oil. As the blocking of the nozzle of the
cylinder is prevented, a gas bearing effect may be effectively performed between the
cylinder and the piston, and thus, abrasion of the cylinder and the piston may be
prevented.
[0115] Embodiments disclosed herein provide a linear compressor in which a gas bearing may
easily operate between a cylinder and a piston, and a refrigerant including a linear
compressor.
[0116] Embodiments disclosed herein provide a linear compressor that may include a shell
including a suction inlet; a cylinder provided in the shell to define a compression
space for a refrigerant; a piston reciprocated in an axial direction within the cylinder;
a discharge valve provided on or at one side of the cylinder to selectively discharge
the refrigerant compressed in the compression space; a nozzle part or nozzle disposed
in the cylinder to introduce at least a portion of the refrigerant discharged through
the discharge valve into the cylinder; and a filter device or filter provided in the
shell. The filter device may include at least one filter member disposed on or in
a refrigerant passage defined from the suction inlet to the nozzle part via the discharge
valve. Foreign substances or oil contained in the refrigerant to be introduced into
the nozzle part may be filtered while passing through the at least one filter member.
[0117] The linear compressor may further include a suction muffler provided in the shell
to reduce noise of the refrigerant suctioned through the suction inlet. The filter
device may include a first filter provided on the suction muffler. The suction muffler
may include a first muffler and a second muffler, and the first filter may be disposed
at a coupled portion between the first and second mufflers.
[0118] The linear compressor may further include a groove part or groove defined in one
of the first muffler or the second muffler, and a protrusion disposed on the other
one of the first muffler or the second muffler. The protrusion may be coupled to the
groove part. Both sides of the first filter may be disposed between the groove part
and the protrusion.
[0119] The first filter may include a magnetic material. The first filter may be formed
of a stainless steel material.
[0120] The linear compressor may further include a frame fixed to an outside of the cylinder.
The filter device may include a second filter disposed in a refrigerant flow space
between the cylinder and the frame.
[0121] The cylinder may include a cylinder body, and a cylinder flange part or flange that
extends in a radial direction of the cylinder body. A recess part or recess, in which
the cylinder flange part may be inserted, and a seat part or seat, on which one surface
of the cylinder flange part may be seated, may be provided on the frame.
[0122] The second filter may be placed on the seat part of the frame. The second filter
may be placed between an outer circumferential surface of the cylinder flange part,
and an inner circumferential surface of the recess part. The second filter may have
a ring shape. Further, the second filter may include a felt formed of polyethylene
terephthalate (PET) fiber.
[0123] The linear compressor may further include a gas inflow part or gas inflow recessed
from an outer circumferential surface of the cylinder to communicate with the nozzle
part. The filter device may include a third filter disposed on or in the gas inflow
part. The third filter may include a thread having a preset or predetermined thickness
or diameter. The thread may be formed of a polyethylene terephthalate (PET) material.
The thread may be wound several times around the gas inflow part.
[0124] Embodiments disclosed herein further provide a refrigerator that may include a linear
compressor including a reciprocating piston and a cylinder to accommodate the piston
and having an outer circumferential surface to introduce a refrigerant; a filter device
provided in the linear compressor to filter the refrigerant introduced through the
outer circumferential surface of the cylinder; a condenser to condense the refrigerant
compressed in the linear compressor; and a dryer to remove foreign substances or oil
contained in the refrigerant condensed in the condenser. The dryer may include an
adsorbent to adsorb the oil contained in the refrigerant. The adsorbent may include
a molecular sieve having a grain shape and a plurality of holes to adsorb the oil.
The adsorbent may include an oil adsorbent paper or felt.
[0125] The dryer may include a first dryer filter disposed within an inlet-side of the dryer;
a second dryer filter that supports the first dryer filter, the second dryer filter
including the adsorbent; and a third dryer filter that supports the second dryer,
the third dryer filter being disposed within an outlet-side of the dryer.
[0126] The filter device may include a first filter including a suction muffler to reduce
flow noise of the refrigerant suctioned into the linear compressor. The filter device
may include a second filter disposed on one side of the cylinder to filter at least
a portion of the refrigerant discharged from the cylinder. The filter device may include
a third filter wound around the outer circumferential surface of the cylinder.
[0127] Any reference in this specification to "one embodiment," "an embodiment," "example
embodiment," etc., means that a particular feature, structure, or characteristic described
in connection with the embodiment is included in at least one embodiment. The appearances
of such phrases in various places in the specification are not necessarily all referring
to the same embodiment. Further, when a particular feature, structure, or characteristic
is described in connection with any embodiment, it is submitted that it is within
the purview of one skilled in the art to effect such feature, structure, or characteristic
in connection with other ones of the embodiments.
[0128] Although embodiments have been described with reference to a number of illustrative
embodiments thereof, it should be understood that numerous other modifications and
embodiments can be devised by those skilled in the art that will fall within the spirit
and scope of the principles of this disclosure. More particularly, various variations
and modifications are possible in the component parts and/or arrangements of the subject
combination arrangement within the scope of the disclosure, the drawings and the appended
claims. In addition to variations and modifications in the component parts and/or
arrangements, alternative uses will also be apparent to those skilled in the art.