Patent ID: 12241460

BEST MODE

Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

It should be understood that when a component is described as being “connected to” or “coupled to” other component, it may be directly connected or coupled to the other component or intervening component(s) may be present.

It will be noted that a detailed description of known arts will be omitted if it is determined that the detailed description of the known arts obscure embodiments of the present disclosure. The accompanying drawings are used to help easily understand various technical features and it should be understood that embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be understood to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings.

In addition, a term of “disclosure” may be replaced by document, specification, description, etc.

FIG.1is a perspective view of a linear compressor100according to a first embodiment of the present disclosure.

Referring toFIG.1, a linear compressor100according to an embodiment of the present disclosure may include a shell111and shell covers112and113coupled to the shell111. In a broad sense, the shell covers112and113can be understood as one configuration of the shell111.

Legs20may be coupled to a lower side of the shell111. The legs20may be coupled to a base of a product on which the linear compressor100is mounted. For example, the product may include a refrigerator, and the base may include a machine room base of the refrigerator. As another example, the product may include an outdoor unit of an air conditioner, and the base may include a base of the outdoor unit.

The shell111may have a substantially cylindrical shape and may be disposed to lie in a horizontal direction or an axial direction.FIG.1illustrates that the shell111is extended in the horizontal direction and has a slightly low height in a radial direction, by way of example. That is, since the linear compressor100can have a low height, there is an advantage in that a height of the machine room can decrease when the linear compressor100is installed in, for example, the machine room base of the refrigerator.

A longitudinal central axis of the shell111coincides with a central axis of a main body of the linear compressor100to be described below, and the central axis of the main body of the linear compressor100coincides with a central axis of a cylinder140and a piston150that constitute the main body of the linear compressor100.

A terminal30may be installed on an outer surface of the shell111. The terminal30may transmit external electric power to a drive unit130of the linear compressor100. More specifically, the terminal30may be connected to a lead line of a coil132b.

A bracket31may be installed on the outside of the terminal30. The bracket31may include a plurality of brackets surrounding the terminal30. The bracket31may perform a function of protecting the terminal30from an external impact, etc.

Both sides of the shell111may be opened. The shell covers112and113may be coupled to both sides of the opened shell111. More specifically, the shell covers112and113may include a first shell cover112coupled to one opened side of the shell111and a second shell cover113coupled to the other opened side of the shell111. An inner space of the shell111may be sealed by the shell covers112and113.

FIG.1illustrates that the first shell cover112is positioned on the right side of the linear compressor100, and the second shell cover113is positioned on the left side of the linear compressor100, by way of example. In other words, the first and second shell covers112and113may be disposed to face each other. It can be understood that the first shell cover112is positioned on an intake side of a refrigerant, and the second shell cover113is positioned on a discharge side of the refrigerant.

The linear compressor100may include a plurality of pipes114,115, and40that are included in the shell111or the shell covers112and113and can suck, discharge, or inject the refrigerant.

The plurality of pipes114,115, and40may include an intake pipe114that allows the refrigerant to be sucked into the linear compressor100, a discharge pipe115that allows the compressed refrigerant to be discharged from the linear compressor100, and a supplementary pipe40for supplementing the refrigerant in the linear compressor100.

For example, the intake pipe114may be coupled to the first shell cover112. The refrigerant may be sucked into the linear compressor100along the axial direction through the intake pipe114.

The discharge pipe115may be coupled to an outer circumferential surface of the shell111. The refrigerant sucked through the intake pipe114may be compressed while flowing in the axial direction. The compressed refrigerant may be discharged through the discharge pipe115. The discharge pipe115may be disposed closer to the second shell cover113than to the first shell cover112.

The supplementary pipe40may be coupled to the outer circumferential surface of the shell111. A worker may inject the refrigerant into the linear compressor100through the supplementary pipe40.

The supplementary pipe40may be coupled to the shell111at a different height from the discharge pipe115in order to prevent interference with the discharge pipe115. Herein, the height may be understood as a distance measured from the leg20in a vertical direction. Because the discharge pipe115and the supplementary pipe40are coupled to the outer circumferential surface of the shell111at different heights, the work convenience can be attained.

On an inner circumferential surface of the shell111corresponding to a location at which the supplementary pipe40is coupled, at least a portion of the second shell cover113may be positioned adjacently. In other words, at least a portion of the second shell cover113may act as a resistance of the refrigerant injected through the supplementary pipe40.

Thus, with respect to a flow path of the refrigerant, a size of the flow path of the refrigerant introduced through the supplementary pipe40is configured to decrease by the second shell cover113while the refrigerant enters into the inner space of the shell111, and to increase again while the refrigerant passes through the second shell cover113. In this process, a pressure of the refrigerant may be reduced to vaporize the refrigerant, and an oil contained in the refrigerant may be separated. Thus, while the refrigerant, from which the oil is separated, is introduced into the piston150, a compression performance of the refrigerant can be improved. The oil may be understood as a working oil present in a cooling system.

FIG.2is a cross-sectional view of the linear compressor100according to the first embodiment of the present disclosure.FIG.3is a cross-sectional perspective view of partial configuration of the linear compressor100according to the first embodiment of the present disclosure.FIG.4is an exploded perspective view of partial configuration of the linear compressor100according to the first embodiment of the present disclosure.FIG.5is a cross-sectional view of partial configuration of the linear compressor100according to the first embodiment of the present disclosure.FIG.6is a perspective view illustrating one side of a rod192and an elastic body191of the linear compressor100according to the first embodiment of the present disclosure.FIG.7is a cross-sectional view illustrating a coupling method of the elastic body191and a sliding portion152in the linear compressor100according to the first embodiment of the present disclosure.

Hereinafter, the linear compressor according to the present disclosure will be described taking, as an example, a linear compressor that sucks and compresses a fluid while a piston linearly reciprocates, and discharges the compressed fluid.

The linear compressor100according to the first embodiment of the present disclosure may include the cylinder140, the piston150, a muffler unit160, a supporter119, the elastic body191, and the rod192, but can be implemented except some of these components and does not exclude additional components.

It can be understood that detailed configuration of a linear compressor according to the present disclosure illustrated inFIGS.8to15, in which the description is omitted later, is the same as detailed configuration of the linear compressor100according to the first embodiment of the present disclosure illustrated inFIGS.2to7.

The linear compressor100may be a component of a refrigeration cycle, and a fluid compressed in the linear compressor100may be a refrigerant circulating the refrigeration cycle. The refrigeration cycle may include a condenser, an expander, an evaporator, etc., in addition to the linear compressor100. The linear compressor100may be used as a component of the cooling system of the refrigerator, but is not limited thereto. The linear compressor100can be widely used in the whole industry.

Referring toFIG.2, the linear compressor100may include a casing110and a main body received in the casing110. The main body of the linear compressor100may include a frame120, the cylinder140fixed to the frame120, the piston150that linearly reciprocates inside the cylinder140, the drive unit130that is fixed to the frame120and gives a driving force to the piston150, and the like. Here, the cylinder140and the piston150may be referred to as compression units140and150.

The linear compressor100may include a bearing means for reducing a friction between the cylinder140and the piston150. The bearing means may be an oil bearing or a gas bearing. Alternatively, a mechanical bearing may be used as the bearing means.

The main body of the linear compressor100may be elastically supported by support springs116and117installed at both ends in the casing110. The support springs116and117may include a first support spring116for supporting the rear of the main body and a second support spring117for supporting a front of the main body. The support springs116and117may include a leaf spring. The support springs116and117can absorb vibrations and impacts generated by a reciprocating motion of the piston150while supporting the internal components of the main body of the linear compressor100.

The casing110may define a sealed space. The sealed space may include an accommodation space101in which the sucked refrigerant is received, an intake space102which is filled with the refrigerant before the compression, a compression space103in which the refrigerant is compressed, and a discharge space104which is filled with the compressed refrigerant.

The refrigerant sucked from the intake pipe114connected to the rear side of the casing110may be filled in the accommodation space101, and the refrigerant in the intake space102communicating with the accommodation space101may be compressed in the compression space103, discharged into the discharge space104, and discharged to the outside through the discharge pipe115connected to the front side of the casing110.

The casing110may include the shell111formed in a substantially cylindrical shape that is open at both ends and is long in a transverse direction, the first shell cover112coupled to the rear side of the shell111, and the second shell cover113coupled to the front side of the shell111. Here, it can be understood that the front side is the left side of the figure and is a direction in which the compressed refrigerant is discharged, and the rear side is the right side of the figure and is a direction in which the refrigerant is introduced. Further, the first shell cover112and the second shell cover113may be formed as one body with the shell11.

The casing110may be formed of a thermally conductive material. Hence, heat generated in the inner space of the casing110can be quickly dissipated to the outside.

The first shell cover112may be coupled to the shell111in order to seal the rear of the shell111, and the intake pipe114may be inserted and coupled to the center of the first shell cover112.

The rear of the main body of the linear compressor100may be elastically supported by the first support spring116in the radial direction of the first shell cover112.

The first support spring116may include a circular leaf spring. A back cover123may be axially elastically supported by a back cover support ember123aformed at an edge of the first support spring116. An opened center portion of the first support spring116may be coupled to an intake guide116aand axially elastically supported.

The intake guide116amay have a through passage formed therein. The intake guide116amay be formed in a cylindrical shape. A front outer circumferential surface of the intake guide116amay be coupled to a central opening of the first support spring116, and a rear end of the intake guide116amay be supported by the first shell cover112. In this instance, a separate intake support member116bmay be interposed between the intake guide116aand an inner surface of the first shell cover112.

A rear side of the intake guide116amay communicate with the intake pipe114, and the refrigerant sucked through the intake pipe114may pass through the intake guide116aand may be smoothly introduced into a muffler unit160to be described below.

A damping member116cmay be disposed between the intake guide116aand the intake support member116b.The damping member116cmay be formed of a rubber material or the like. Hence, a vibration that may occur in the process of sucking the refrigerant through the intake pipe114can be prevented from being transmitted to the first shell cover112.

The second shell cover113may be coupled to the shell111to seal the front side of the shell111, and the discharge pipe115may be inserted and coupled through a loop pipe115a.The refrigerant discharged from the compression space103may pass through a discharge cover assembly180and then may be discharged into the refrigeration cycle through the loop pipe115aand the discharge pipe115.

A front side of the main body of the linear compressor100may be elastically supported by the second support spring117in the radial direction of the shell111or the second shell cover113.

The second support spring117may include a circular leaf spring. An opened center portion of the second support spring117may be supported by a first support guide117bin a rearward direction with respect to the discharge cover assembly180. An edge of the second support spring117may be supported by a support bracket117ain a forward direction with respect to the inner surface of the shell111or the inner circumferential surface of the shell111adjacent to the second shell cover113.

Unlike the configuration illustrated inFIG.2, the edge of the second support spring117may be supported in the forward direction with respect to the inner surface of the shell111or the inner circumferential surface of the shell111adjacent to the second shell cover113through a separate bracket (not shown) coupled to the second shell cover113.

The first support guide117bmay be formed in a cylindrical shape. A cross section of the first support guide117bmay have a plurality of diameters. A front side of the first support guide117bmay be inserted into a central opening of the second support spring117, and a rear side of the first support guide117bmay be inserted into a central opening of the discharge cover assembly180. A support cover117cmay be coupled to the front side of the first support guide117bwith the second support spring117interposed therebetween. A cup-shaped second support guide117dthat is recessed forward may be coupled to the front side of the support cover117c.A cup-shaped third support guide117ethat corresponds to the second support guide117dand is recessed rearward may be coupled to the inside of the second shell cover113. The second support guide117dmay be inserted into the third support guide117eand may be supported in the axial direction and/or the radial direction. In this instance, a gap may be formed between the second support guide117dand the third support guide117e.

The frame120may include a body portion121supporting the outer circumferential surface of the cylinder140, and a first flange portion122that is connected to one side of the body portion121and supports the drive unit130. The frame120may be elastically supported with respect to the casing110by the first and second support springs116and117together with the drive unit130and the cylinder140.

The body portion121may wrap the outer circumferential surface of the cylinder140. The body portion121may be formed in a cylindrical shape. The first flange portion122may extend from a front end of the body portion121in the radial direction.

The cylinder140may be coupled to an inner circumferential surface of the body portion121. An inner stator134may be coupled to an outer circumferential surface of the body portion121. For example, the cylinder140may be pressed and fitted to the inner circumferential surface of the body portion121, and the inner stator134may be fixed using a separate fixing ring (not shown).

An outer stator131may be coupled to a rear surface of the first flange portion122, and the discharge cover assembly180may be coupled to a front surface of the first flange portion122. For example, the outer stator131and the discharge cover assembly180may be fixed through a mechanical coupling means.

On one side of the front surface of the first flange portion122, a bearing inlet groove125aforming a part of the gas bearing may be formed, a bearing communication hole125bpenetrating from the bearing inlet groove125ato the inner circumferential surface of the body portion121may be formed, and a gas groove125ccommunicating with the bearing communication hole125bmay be formed on the inner circumferential surface of the body portion121.

The bearing inlet groove125amay be recessed to a predetermined depth along the axial direction. The hearing communication hole125bis a hole having a smaller cross-sectional area than the bearing inlet groove125aand may be inclined toward the inner circumferential surface of the body portion121. The gas groove125cmay be formed in an annular shape having a predetermined depth and an axial length on the inner circumferential surface of the body portion121. Alternatively, the gas groove125cmay be formed on the outer circumferential surface of the cylinder140in contact with the inner circumferential surface of the body portion121, or formed on both the inner circumferential surface of the body portion121and the outer circumferential surface of the cylinder140.

In addition, a gas inlet142corresponding to the gas groove125cmay be formed on the outer circumferential surface of the cylinder140. The gas inlet142forms a kind of nozzle in the gas bearing.

The frame120and the cylinder140may be formed of aluminum or an aluminum alloy material.

The cylinder140may be formed in a cylindrical shape in which both ends are opened. The piston150may be inserted through a rear end of the cylinder140. A front end of the cylinder140may be closed via a discharge valve assembly170. The compression space103may be formed between the cylinder140, a front end of the piston150, and the discharge valve assembly170. Here, the front end of the piston150may be referred to as a head portion151. The volume of the compression space103increases when the piston150moves backward, and decreases as the piston150moves forward. That is, the refrigerant introduced into the compression space103may be compressed while the piston150moves forward, and may be discharged through the discharge valve assembly170.

The cylinder140may include a second flange portion141disposed at the front end. The second flange portion141may bend to the outside of the cylinder140. The second flange portion141may extend in an outer circumferential direction of the cylinder140. The second flange portion141of the cylinder140may be coupled to the frame120. For example, the front end of the frame120may include a flange groove corresponding to the second flange portion141of the cylinder140, and the second flange portion141of the cylinder140may be inserted into the flange groove and coupled through a coupling member.

A gas bearing means may be provided to supply a discharge gas to a gap between an outer circumferential surface of the piston150and an inner circumferential surface of the cylinder140and lubricate between the cylinder140and the piston150with gas. The discharge gas between the cylinder140and the piston150may provide a levitation force to the piston150to reduce a friction generated between the piston150and the cylinder140.

For example, the cylinder140may include the gas inlet142. The gas inlet142may communicate with the gas groove125cformed on the inner circumferential surface of the body portion121. The gas inlet142may pass through the cylinder140in the radial direction. The gas inlet142may guide the compressed refrigerant introduced in the gas groove125cbetween the inner circumferential surface of the cylinder140and the outer circumferential surface of the piston150. Alternatively, the gas groove125cmay be formed on the outer circumferential surface of the cylinder140in consideration of the convenience of processing.

An entrance of the gas inlet142may be formed relatively widely, and an exit of the gas inlet142may be formed as a fine through hole to serve as a nozzle. The entrance of the gas inlet142may further include a filter (not shown) blocking the inflow of foreign matter. The filter may be a metal mesh filter, or may be formed by winding a member such as fine thread.

The plurality of gas inlets142may be independently formed. Alternatively, the entrance of the gas inlet142may be formed as an annular groove, and a plurality of exits may be formed along the annular groove at regular intervals. The gas inlet142may be formed only at the front side based on the axial direction center of the cylinder140. On the contrary, the gas inlet142may be formed at the rear side based on the axial direction center of the cylinder140in consideration of the sagging of the piston150.

The piston150is inserted into the opened rear end of the cylinder140and is provided to seal the rear of the compression space103.

The piston150may include a head portion151and a sliding portion152. The head portion151may be formed in a disc shape. The head portion151may be partially open. The head portion151may partition the compression space103. The sliding portion152may extend rearward from a radially outer edge of the head portion151. The sliding portion152may be formed in a cylindrical shape. The inside of the sliding portion152may be empty, and a front of the sliding portion152may be partially sealed by the head portion151. A rear of the sliding portion152may be opened and connected to the muffler unit160. The head portion151may be provided as a separate member coupled to the sliding portion152. Alternatively, the head portion151and the sliding portion152may be formed as one body.

The linear compressor100may include the elastic body191. The elastic body191may be disposed in the piston150. An outer end of the elastic body191may be coupled to an inner circumferential surface of the piston150. A radially central area of the elastic body191may be coupled to one side of the rod192. The piston150may be elastically supported axially and/or radially by the elastic body191coupled to one side of the rod192.

Referring toFIGS.4and7, the elastic body191may extend radially outward about the axis. The elastic body191may be radially disposed and may be a leaf spring formed in a disk shape. An outer edge of the elastic body191may be integrally formed. When the outer edge of the elastic body191is integrally formed, a coupling force with an inner circumferential surface of the sliding portion152can be improved, and the behavior of the piston150can be easily controlled.

When the elastic body191is formed of the leaf spring, radial elasticity may be stronger than axial elasticity. When the elastic body191has the stronger radial elasticity than the axial elasticity, the eccentricity of the supporter119with respect to the elastic body191can be minimized. When the axial elasticity of the elastic body191is weak, flexible tilting may be possible.

Specifically, the supporter119may be elastically supported by a plurality of resonant springs118coupled to a spring seat portion119c.The supporter119may be a mover that is coupled to a magnet frame136, to which a magnet135is coupled, and reciprocates axially. In this case, the alignment between the axis of the linear compressor100and the axis of the supporter119may be misaligned. When the piston150is not flexibly tilted with respect to the supporter119, the axial alignment of the piston150with respect to the cylinder140may also be misaligned. Therefore, a friction and/or contact may occur between the piston150and the cylinder140. The friction may wear and damage the components.

When the elastic body191is formed of the leaf spring, a tilting freedom of the piston150with respect to the supporter119may increase. Therefore, the piston150can easily maintain the axial alignment by the gas bearing on the inside of the cylinder140. At the same time as this, since the eccentricity of the supporter119and/or the magnet frame136with respect to the piston150can be reduced, a gap in the drive unit130can be kept relatively constant. Through this, since the contact and/or friction between the components can be reduced, a damage of the component and noise generation can be prevented. Hence, the reliability of the linear compressor100can be improved, and the efficiency of the linear compressor100can also be improved.

The elastic body191may include a plurality of first flow holes191a.The refrigerant may flow axially from the inside of the piston150through the plurality of first flow holes191a.

The plurality of first flow holes191amay be disposed radially about the axis. Each of the plurality of first flow holes191amay be formed in a spiral shape away from the axis. Alternatively, the plurality of first flow holes191amay be formed in various shapes so as to secure the proper elasticity of the elastic body191. The plurality of first flow holes191amay be understood as slits formed between elastic elements of the leaf spring. Accordingly, the elasticity of the elastic body191may be controlled by adjusting the shape, the size, or the number of the plurality of first flow holes191a.

An intake port154may axially overlap at least a part of the plurality of first flow holes191a.In the linear compressor100according to the first embodiment of the present disclosure, the refrigerant coming from the muffler unit160passes through the plurality of first flow holes191aof the elastic body191, and then is introduced into the compression space103through the intake port154. In this instance, when the intake port154axially overlaps the plurality of first flow holes191a,the refrigerant passing through the plurality of first flow holes191acan be smoothly introduced into the intake port154.

When viewed axially, a sum of the areas of the plurality of first flow holes191amay he greater than a sum of the areas of the intake ports154. When the sum of the areas of the plurality of first flow holes191ais greater than the sum of the areas of the intake ports154, the present disclosure can prevent a problem in which an amount of the refrigerant introduced into the intake port154decreases.

When viewed axially, the sum of the areas of the plurality of first flow holes191amay be greater than the area of a cross-section of a narrowest portion of an internal flow path105formed inside the muffler unit160. When the sum of the areas of the plurality of first flow holes191ais at least greater than a cross-sectional area of the narrowest portion of a cross-section of the internal flow path105formed inside the muffler unit160, the refrigerant passing through the internal flow path105can entirely reach the intake port154.

Referring to (a) ofFIG.6, the sliding portion152may include a groove193. The groove193is formed on the inner circumferential surface of the sliding portion152, and the elastic body191may be coupled to the groove193. The groove193may be formed in a circumferential direction at a portion coupled to an outer circumferential surface of the elastic body191. A radius of the elastic body191may be larger than a radius of an inner circumferential surface of a portion of the sliding portion152in which the groove193is not formed. The radius of the elastic body191may be formed to have a radius corresponding to a radius of the groove193. The elastic body191may be coupled to the piston150as the outer circumferential surface of the elastic body191is seated on the groove193formed on the inner circumferential surface of the sliding portion152. The groove193may guide the position of the elastic body191with respect to the piston150.

Alternatively, the groove193may be formed only in a portion of an area contacting the elastic body191. For example, three grooves193may be formed in the circumferential direction at intervals of 120 degrees around the axis. In this case, a plurality of protrusions (not shown) may be formed at positions where the grooves193are formed at the outer circumferential surface of the elastic body191. The elastic body191may be coupled to the piston150as the plurality of protrusions (not shown) are seated on the grooves193. A radius of a portion of the elastic body191where the plurality of protrusions (not shown) are not formed may be equal to or less than a radius of the inner circumferential surface of the sliding portion152. The groove193may guide a rotation direction position.

Referring to (b) and (c) ofFIG.6, a first coupling groove194may be formed on one of the outer circumferential surface of the elastic body191and the inner circumferential surface of the sliding portion152, and the other may include a coupling protrusion195coupled to the first coupling groove194. The coupling protrusion195may be formed as a separate member from the elastic body191and/or the piston150.

Referring to (b) ofFIG.6, a seating groove196in which the coupling protrusion195can be seated may be formed on the outer circumferential surface of the elastic body191, and a spring197may be disposed in the seating groove196. The elastic body191may be coupled to the piston150in such a way that the elastic body191is inserted from the rear of the piston150. When the elastic body191is inserted from the rear of the piston150, the coupling protrusion195may be pressed. Further, when the coupling protrusion195is disposed at the position where the first coupling groove194is formed, the coupling protrusion195may protrude outward by an elastic force of the spring197disposed in the seating groove196. Hence, the elastic body191may be fixed to the first coupling groove194.

Referring to (c) ofFIG.6, a seating groove196in which the coupling protrusion195can be seated may be formed on the inner circumferential surface of the sliding portion152. A spring197may be disposed in the seating groove196. The elastic body191may be coupled to the piston150in such a way that the elastic body191is inserted from the rear of the piston150. When the elastic body191is inserted from the rear of the piston150, the coupling protrusion195may be pressed. Further, when the first coupling groove194is disposed at the position where the coupling protrusion195is formed, the coupling protrusion195may protrude inward by an elastic force of the spring197disposed in the seating groove196. Hence, the elastic body191may be fixed to the first coupling groove194.

The first coupling groove194and/or the coupling protrusion195may be formed in the circumferential direction. That is, the first coupling groove194and/or the coupling protrusion195may be formed in a ring shape. Alternatively, the first coupling groove194and/or the coupling protrusion195may be formed in a part of the circumference. For example, three first coupling grooves194may be formed on the inner circumferential surface of the sliding portion152in the circumferential direction at intervals of 120 degrees around the axis. In addition, three coupling protrusions195may be formed at positions corresponding to the positions where the first coupling grooves194are formed on the outer circumferential surface of the elastic body191.

Referring to (d) ofFIG.6, the outer circumferential surface of the elastic body191may be formed of a male screw. A portion to which the elastic body191is coupled on the inner circumferential surface of the sliding portion152may be formed of a female screw. The elastic body191may be screw-coupled to the inner circumferential surface of the sliding portion152. In this case, the elastic body191can be simply coupled to the piston150without a separate member.

A radius of a rear portion of the elastic body191at the inner circumferential surface of the sliding portion152may be greater than the radius of the elastic body191. Through this, when the elastic body191is inserted from the rear of the piston150, the elastic body191does not interfere with the inner circumferential surface of the sliding portion152and may be disposed at the coupling position. A radius of a front portion of the elastic body191at the inner circumferential surface of the sliding portion152may be less than the radius of the elastic body191at the inner circumferential surface of the sliding portion152. In this case, a portion having a small radius in the inner circumferential surface of the sliding portion152may serve as a stopper when the elastic body191is screw-coupled to the inner circumferential surface of the sliding portion152.

A rotation direction in which the elastic body191is screw-coupled to the rod192and a rotation direction in which the sliding portion152is screw-coupled to the elastic body191may be the same. For example, when a direction in which the elastic body191is screw-coupled to one side of the rod192is a right-handed screw direction, a direction in which the piston150is screw-coupled to the elastic body191may be the right-handed screw direction. Through this, when the piston150is screw-coupled to the elastic body191, the elastic body191can be tightened at the same time. Hence, the piston150, the elastic body191, and the rod192can be firmly coupled.

Unlike the configuration illustrated inFIGS.2to7, the elastic body191and the piston150may be integrally formed. Specifically, the elastic body191may extend to a radially inner side of the sliding portion152and may be coupled to one side of the rod192in a radially central area. In this case, since the piston150can be coupled to the supporter119without a separate process of coupling the elastic body191to the piston150, the manufacturing process can be simplified. For example, a coupling hole191bto which one side of the rod192can be coupled may be formed in the radially central area of the elastic body191, the coupling hole191bmay be formed of a female screw, and one side of the rod192may be formed of a male screw. In this case, the piston150integrally formed with the elastic body191may be coupled to one side of the rod192by turning it.

The linear compressor100may include the rod192. The rod192may extend axially. The rod192may be disposed inside the internal flow path105that is formed inside the muffler unit160and extends axially. One side of the rod192may be coupled to the radially central area of the elastic body191, and other side may be connected to a radially central area of a plate119b.An elastic force of the resonant spring118may be transmitted to the rod192through the supporter119. The elastic force transmitted to the rod192may be transmitted to the piston150through the elastic body191.

The rod192may be formed of a rigid material. If the rod192is formed of an elastic material, eccentricity of the supporter119and the magnet frame136connected to the supporter119may occur even if the axial alignment of the piston150is maintained at the inner circumferential surface of the cylinder140. In this case, it may be difficult for the magnet135coupled to the magnet frame136to maintain a constant gap between the outer stator131and the inner stator134. If the gap of the drive unit130is not constant, the efficiency of the linear compressor100may be reduced, and a contact and/or friction between the outer stator131and/or the inner stator134and the magnet135may occur. This may cause problems of component damage and noise generation. When the rod192is formed of the rigid material, the axial alignment of the piston150can be achieved, and at the same time, the eccentricity of the supporter119and/or the magnet frame136can be prevented. Through this, the present disclosure can solve the problems of component damage and noise generation that may occur in the gap of the drive unit130, and can improve the efficiency of the linear compressor100.

When the rod192is formed of the rigid material, elastic deformation occurs only in the elastic body191. Therefore, a rotation point of the piston150can be easily designed. Through this, the behavior of the piston150can be easily controlled.

The elastic body191and the rod192may be rigidly coupled. For example, the elastic body191and the rod192may be screw-coupled. Specifically, the rod192may be formed of a male screw. Further, the elastic body191may include the coupling hole191bthat is formed of a female screw in the radially central area of the elastic body191. The coupling hole191bmay be screw-coupled to one side of the rod192. Through this, the elastic body191can be simply coupled to the rod192without a separate coupling member. In addition, when the rod192is formed of the rigid material and is rigidly coupled to the elastic body191, an elastically deformed portion is limited to the elastic body191. Therefore, the rotation point of the piston150can be easily designed. In addition, since the flexibility of the tilting of the piston150can be adjusted only by coupling the elastic body191with the proper elasticity to the behavior of the piston150, the behavior of the piston150can be easily controlled.

Unlike the configuration illustrated inFIGS.2to7, the elastic body191and the rod192may be integrally formed. When the elastic body191and the rod192are integrally formed, it is possible to prevent problems, such as noise generation, due to a gap that may occur at a coupling portion of the elastic body191and the rod192. In addition, since the elastic body191and the rod192can be manufactured at once through a single manufacturing process, the manufacturing process can be simplified.

The piston150may include the intake port154. The intake port154may pass through the head portion151. The intake port154may communicate the intake space102and the compression space103inside the piston150with each other. For example, the refrigerant flowing from the accommodation space101to the intake space102inside the piston150may pass through the intake port154and may be sucked into the compression space103between the piston150and the cylinder140. The refrigerant may flow from the intake space102to the compression space103through the intake port154. The intake port154may axially overlap at least a part of the plurality of first flow holes191a.When viewed axially, a sum of the areas of the plurality of first flow holes191aformed in the elastic body191may be greater than a sum of the areas of the intake ports154.

The intake port154may extend in an axial direction of the piston150. The intake port154may be inclined along the axial direction of the piston150. For example, the intake port154may extend to be inclined in a direction away from the central axis as it goes to the rear of the piston150.

A cross section of the intake port154may be formed in a circular shape. The intake port154may have a constant inner diameter. Alternatively, the intake port154may be formed as a long hole in which an opening extends in the radial direction of the head portion151, and may be configured such that the inner diameter becomes larger as it goes to the rear.

The plurality of intake ports154may be formed in at least one of the radial direction and the circumferential direction of the head portion151.

The head portion151of the piston150adjacent to the compression space103may be provided with an intake valve155for selectively opening and closing the intake port154. The intake valve155may operate by elastic deformation to open or close the intake port154. That is, the intake valve155may pass through the intake port154and may be elastically deformed to open the intake port154by a pressure of the refrigerant flowing into the compression space103.

The piston150may be connected to a magnet135. The magnet135may reciprocate forward and backward in response to the movement of the piston150. The inner stator134and the cylinder140may be disposed between the magnet135and the piston150. The magnet135and the piston150may be connected to each other by the magnet frame136that is formed by detouring the cylinder140and the inner stator134to the rear.

The linear compressor100may include the muffler unit160. The muffler unit160may be inserted into the piston150from the rear of the piston150. The muffler unit160may be disposed at the rear of the elastic body191. The muffler unit160may reduce noise generated in the process of introducing the refrigerant into the piston150. The refrigerant sucked through the intake pipe114may flow into the intake space102in the piston150via the muffler unit160.

Referring toFIG.5, the muffler unit160may be formed as a single member, or may be formed by combining a plurality of members. The muffler unit160may be coupled to the piston150to reciprocate axially together with the piston150. The muffler unit160may reduce the noise generated in the compression space103.

The muffler unit160may include the internal flow path105. The internal flow path105may be formed inside the muffler unit160. The internal flow path105may extend axially. A front end of the internal flow path105may communicate with the intake space102formed inside the piston150, and a rear end of the internal flow path105may communicate with the accommodation space101formed inside the casing110. The internal flow path105may communicate from a rear end to a front end of the muffler unit160. The internal flow path105may be understood as a passage through which the refrigerant introduced from the rear end of the muffler unit160can flow to the front of the muffler unit160.

A radius of the internal flow path105may increase as it goes to the axial front. A radially outer portion of the plurality of first flow holes191aformed in the elastic body191may be formed to be wider than a radially inner portion of the plurality of first flow holes191a. Further, in order to secure the proper elasticity of the intake valve155, the intake port154formed in the head portion151of the piston150may also be formed to be biased radially outward. Therefore, when a radius of the front end of the internal flow path105increases as it goes to the front axially, the refrigerant can be guided radially outward while flowing from the radial rear to the radial front. Therefore, the refrigerant passing through the internal flow path105can be more effectively introduced into the plurality of first flow holes191aand/or the intake ports154.

A refrigerant inlet163may be formed at the rear end of the internal flow path105. The refrigerant inlet163may be formed to have a radius to the extent that it can axially overlap some or all of second flow holes119dformed in the plate119b.The refrigerant introduced from the rear of the casing110is introduced into the refrigerant inlet163through the second flow hole119d.In this instance, when the refrigerant inlet163and the second flow hole119dformed in the plate119baxially overlap each other, the refrigerant introduced from the rear of the plate119bcan be effectively introduced into the muffler unit160.

The muffler unit160may include a noise space106. The noise space106may be formed on a radially outer side of the internal flow path105. The internal flow path105and the noise space106may communicate with each other. A radius of an inner circumferential surface of the noise space106may be greater than a radius of an inner circumferential surface of the internal flow path105.

Referring toFIG.5, all or part of the noise space106may be disposed in the noise space106. That is, when the muffler unit160is inserted into the inside of the piston150from the rear of the piston150, all or part of the noise space106may be inserted into the piston150.

Unlike the configuration illustrated inFIG.5, the noise space106may be disposed at the rear of the piston, and the internal flow path105may extend to the front of the noise space106and may be disposed inside the piston150.

When the linear compressor100is driven, the refrigerant may be compressed in the compression space103inside the cylinder by an axial reciprocating motion of the piston150, and may be discharged to the discharge space104. In this process, a pressure of the refrigerant may change, and a compression noise of the refrigerant may occur. The compression noise generated in the compression space103and the piston150may move backward along the internal flow path105. The compression noise generated in the front of the piston150may be radiated to the noise space106while moving backward along the internal flow path105. When the internal flow path105passes through the noise space106, a cross-sectional area of a flow path through which the refrigerant passes rapidly increases. Therefore, a sound pressure of the compression noise can be reduced, and the compression noise may be attenuated. In addition, the compressed noise entering the noise space106may be dissipated while being reflected on an inner wall of the noise space106.

The linear compressor100may include the resonant spring118. The resonant spring118may amplify a vibration implemented by the reciprocating motion of the magnet135and the piston150to thereby achieve the effective compression of the refrigerant. Specifically, the resonant spring118may be adjusted to a frequency corresponding to the natural frequency of the piston150and may allow the piston150to perform a resonant motion. Further, the resonant spring118may induce a stable movement of the piston150to reduce vibration and noise generation.

The resonant spring118may be a coil spring extending axially. Both ends of the resonant spring118may be connected to a vibrating body and a fixed body, respectively. For example, one end of the resonant spring118may be connected to the magnet frame136, and other end may be connected to the back cover123. Thus, the resonant spring118may be elastically deformed between the vibrating body vibrating at one end and the fixed body fixed at the other end.

The natural frequency of the resonant spring118is designed to match a resonance frequency of the magnet135and the piston150during operation of the linear compressor100, thereby amplifying the reciprocating motion of the piston150. However, since the back cover123provided as the fixed body is elastically supported on the casing110through the first support spring116, the back cover123may not be strictly fixed.

The resonant spring118may include a first resonant spring118asupported on a rear side of the supporter119based on the supporter119and a second resonant spring118bsupported on a front side of the supporter119.

The linear compressor100may include the supporter119. The supporter119may serve to transmit an elastic of the resonant spring118to the piston150.

The supporter119may include a body portion119a,a spring seat portion119cextending to a radially outer side of the body portion119a,and the plate119bextending to a radially inner side of the body portion119a.

The supporter119may include the plate119b.A radially central area of the plate119bmay be coupled to the other side of the rod192.

The plate119bmay be connected to the rod192. The plate119band the rod192may be integrally formed. When the plate119band the rod192are integrally formed, it is possible to prevent a problem such as noise generation due to a gap that may occur at a fastening portion. Further, when the supporter119and the rod192are integrally formed, the elastic force of the resonant spring118transmitted to the supporter119can be fully transmitted to the rod192. Therefore, the elastic force of the resonant spring118can be effectively transmitted to the piston150. In addition, since the supporter119and the rod192can be manufactured at once through a single manufacturing process, the manufacturing process can be simplified.

Alternatively, the plate119band the rod192may be rigidly coupled. For example, a male screw is formed in one of the other side of the rod192and the radially central area of the plate119b, and a female screw is formed in the other, so that the rod192can be screw-coupled to the plate119b.Through this, the rod192can be simply coupled to the plate119bwithout a separate coupling member.

A direction in which the elastic body191is screw-coupled to one side of the rod192and a direction in which the rod192is screw-coupled to the plate119bmay be the same. For example, when the direction in Which the elastic body191is screw-coupled to one side of the rod192is a right-handed screw direction, a direction in which the other side of the rod192is screw-coupled to the radially central area of the plate119bmay be the right-handed screw direction. Through this, when the elastic body191is screw-coupled to one side of the rod192, the rod192can be tightened to the plate119bat the same time. Hence, the elastic body191, the rod192, and the plate119bcan be firmly coupled.

The plate119bmay include the second flow hole119d.The second flow hole119dmay be formed on a radially outer side of the rod192. When viewed axially, the second flow hole119dmay be formed in an inner area of the inner circumferential surface of the sliding portion152of the piston150. The refrigerant introduced from the rear of the casing110through the second flow hole119dmay be introduced into the muffler unit160.

The plurality of second flow holes119dmay be provided. For example, three second flow holes119dmay be formed about the axis, and the plurality of second flow holes119dmay be formed radially about the axis. The present disclosure is not limited thereto, and the second flow holes119dmay be formed in various numbers.

The refrigerant inlet163formed at the rear end of the muffler unit160may be formed to have a radius to the extent that it can axially overlap some or all of the second flow holes119dformed in the plate119b.When the refrigerant inlet163axially overlaps some or all of the second flow holes119d,the refrigerant can be effectively introduced into the muffler unit160as described above.

The plate119bmay include a third flow hole119e.The third flow hole119emay be formed in a radially outer portion of the plate119b.The refrigerant in the accommodation space101inside the casing110may flow through the third flow hole119e.The third flow hole119emay guide the refrigerant, that has not been yet introduced into the front of the plate119bthrough the second flow hole119d,to the front of the plate119b.

The supporter119may include the body portion119a.The body portion119amay be coupled to the outside of the plate119b.The body portion119amay be formed in a substantially cylindrical shape and may be formed in a shape surrounding an outer circumferential surface of the plate119b.

An opening119fopened radially may be formed on a side surface of the body portion119a.Through the opening119fformed on the side surface of the body portion119a,not only the refrigerant at the rear of the plate119bbut also the refrigerant at the radially outer side of the body portion119amay be introduced into the inside of the body portion119a,and then may be introduced into the muffler unit160through the second flow hole119dand/or the third flow hole119e.The efficiency of the linear compressor100can be improved by using the refrigerant filled in the inside of the accommodation space101through the opening119fas efficiently as possible as described above.

The body portion119amay include a portion extending to the front of the plate119b.In this instance, a radius R1of an inner circumferential surface of a front end of the body portion119amay be less than a radius R2of the plate119b.A portion of the body portion119adisposed in front of the plate119bmay have a shape in which the radius of the inner circumferential surface deceases as it goes to the front. The portion of the body portion119adisposed in front of the plate119bmay be understood to have a funnel shape. Through this, the refrigerant flowing in the front of the plate119bthrough the third flow hole119efrom the rear of the plate119band/or the outside of the body portion119acan be guided radially inward. The refrigerant guided radially inward can be effectively introduced into the muffler unit160, and the efficiency of the linear compressor100can be improved.

The supporter119may include the spring seat portion119c.The spring seat portion119cmay extend radially outward from the outer circumferential surface of the body portion119a.The plurality of spring seat portions119cmay be provided. The plurality of spring seat portions119cmay be disposed radially about the axis.

The first resonant spring118amay be disposed between a rear surface of a stator cover137and a front surface of the spring seat portion119c.The plurality of first resonant springs118amay be provided. For example, when the three spring seat portions119care provided, the plurality of spring seat portions119cmay be disposed radially about the axis, and the first resonant springs118amay be disposed in pairs for each spring seat portion119cin the circumferential direction.

In this case, it may be understood that the three pairs of first resonant springs118aare disposed radially about the axis. The plurality of first resonant springs118amay be disposed to have symmetry about the axis. Through this, the present disclosure can minimize a lateral force generated from the plurality of first resonant springs118a,and thus can prevent and/or eccentricity of the mover.

The second resonant spring118bmay be disposed between a rear surface of the spring seat portion119cand a front surface of the back cover123. The plurality of second resonant spring118bmay be provided. For example, when the three spring seat portions119care provided, the plurality of spring seat portions119cmay be disposed radially about the axis, and the second resonant springs118bmay be disposed in pairs for each spring seat portion119cin the circumferential direction.

In this case, it may be understood that the three pairs of second resonant springs118bare disposed radially about the axis. The plurality of second resonant springs118bmay be disposed to have symmetry about the axis. Through this, the present disclosure can minimize a lateral force generated from the plurality of second resonant springs118b,and thus can prevent tilting and/or eccentricity of the mover.

The first resonant springs118aand the second resonant springs118bmay be disposed axially side by side, or may be alternately disposed axially.

The discharge valve assembly170may include a discharge valve171and a valve spring172that is provided on a front side of the discharge valve171to elastically support the discharge valve171. The discharge valve assembly170may selectively discharge the compressed refrigerant in the compression space103. Here, the compression space103means a space between the intake valve155and the discharge valve171.

The discharge valve171may be disposed to be supportable on the front surface of the cylinder140. The discharge valve171may selectively open and close the front opening of the cylinder140. The discharge valve171may operate by elastic deformation to open or close the compression space103. The discharge valve171may be elastically deformed to open the compression space103by the pressure of the refrigerant flowing into the discharge space104through the compression space103. For example, the compression space103may maintain a sealed state while the discharge valve171is supported on the front surface of the cylinder140, and the compressed refrigerant of the compression space103may be discharged into an opened space in a state where the discharge valve171is spaced apart from the front surface of the cylinder140.

The valve spring172may be provided between the discharge valve171and the discharge cover assembly180to provide axially an elastic force. The valve spring172may be provided as a compression coil spring, or may be provided as a leaf spring in consideration of an occupied space or reliability.

When the pressure of the compression space103is equal to or greater than a discharge pressure, the valve spring172may open the discharge valve171while deforming forward, and the refrigerant may be discharged from the compression space103and discharged into a first discharge space104aof the discharge cover assembly180. When the discharge of the refrigerant is completed, the valve spring172provides a restoring force to the discharge valve171and thus can allow the discharge valve171to be closed.

A process of introducing the refrigerant into the compression space103through the intake valve155and discharging the refrigerant of the compression space103into the discharge space104through the discharge valve171is described as follows.

In the process in which the piston150linearly reciprocates in the cylinder140, when the pressure of the compression space103is equal to or less than a predetermined intake pressure, the intake valve155is opened and thus the refrigerant is sucked into a compression space103. On the other hand, when the pressure of the compression space103exceeds the predetermined intake pressure, the refrigerant of the compression space103is compressed in a state in which the intake valve155is closed.

When the pressure of the compression space103is equal to or greater than the predetermined intake pressure, the valve spring172deforms forward and opens the discharge valve171connected to the valve spring172, and the refrigerant is discharged from the compression space103to the discharge space104of the discharge cover assembly180. When the discharge of the refrigerant is completed, the valve spring172provides a restoring force to the discharge valve171and allows the discharge valve171to be closed, thereby sealing a front of the compression space103.

The discharge cover assembly180is installed at the front of the compression space103, forms a discharge space104for receiving the refrigerant discharged from the compression space103, and is coupled to a front of the frame120to thereby reduce a noise generated in the process of discharging the refrigerant from the compression space103. The discharge cover assembly180may be coupled to a front of the first flange portion122of the frame120while receiving the discharge valve assembly170. For example, the discharge cover assembly180may be coupled to the first flange portion122through a mechanical coupling member.

An O-ring166may be provided between the discharge cover assembly180and the frame120to prevent the refrigerant in a gasket165for thermal insulation and the discharge space104from leaking.

The discharge cover assembly180may be formed of a thermally conductive material. Therefore, when a high temperature refrigerant is introduced into the discharge cover assembly180, heat of the refrigerant may be transferred to the casing110through the discharge cover assembly180and dissipated to the outside of the linear compressor.

The discharge cover assembly180may include one discharge cover, or may be arranged so that a plurality of discharge covers sequentially communicate with each other. When the discharge cover assembly180is provided with the plurality of discharge covers, the discharge space104may include a plurality of spaces partitioned by the respective discharge covers. The plurality of spaces may be disposed in a front-rear direction and may communicate with each other.

For example, when there are three discharge covers, the discharge space104may include a first discharge space104abetween the frame120and a first discharge cover181coupled to the front side of the frame120, a second discharge space104bbetween the first discharge cover181and a second discharge cover182that communicates with the first discharge space104aand is coupled to a front side of the first discharge cover181, and a third discharge space104cbetween the second discharge cover182and a third discharge cover183that communicates with the second discharge space104band is coupled to a front side of the second discharge cover182.

The first discharge space104amay selectively communicate with the compression space103by the discharge valve171, the second discharge space104bmay communicate with the first discharge space104a,and the third discharge space104cmay communicate with the second discharge space104b.Hence, as the refrigerant discharged from the compression space103sequentially passes through the first discharge space104a,the second discharge space104b,and the third discharge space104c,a discharge noise can be reduced, and the refrigerant can be discharged to the outside of the casing110through the loop pipe115aand the discharge pipe115communicating with the third discharge cover183.

The drive unit130may include the outer stator131that is disposed between the shell111and the frame120and surrounds the body portion121of the frame120, the inner stator134that is disposed between the outer stator131and the cylinder140and surrounds the cylinder140, and the magnet135disposed between the outer stator131and the inner stator134.

The outer stator131may be coupled to the rear of the first flange portion122of the frame120, and the inner stator134may be coupled to the outer circumferential surface of the body portion121of the frame120. The inner stator134may be spaced apart from the inside of the outer stator131, and the magnet135may be disposed in a space between the outer stator131and the inner stator134.

The outer stator131may be equipped with a winding coil, and the magnet135may include a permanent magnet. The permanent magnet may be comprised of a single magnet with one pole or configured by combining a plurality of magnets with three poles.

The outer stator131may include a coil winding body132surrounding the axial direction in the circumferential direction, and a stator core133stacked while surrounding the coil winding body132. The coil winding body132may include a hollow cylindrical bobbin132aand a coil132bwound in a circumferential direction of the bobbin132a.A cross section of the coil132bmay be formed in a circular or polygonal shape and, for example, may have a hexagonal shape. In the stator core133, a plurality of lamination sheets may be laminated radially, or a plurality of lamination blocks may be laminated along the circumferential direction.

The front side of the outer stator131may be supported by the first flange portion122of the frame120, and the rear side of the outer stator131may be supported by a stator cover137. For example, the stator cover137may be provided in a hollow disc shape, a front surface of the stator cover137may be supported by the outer stator131, and a rear surface of the stator cover137may be supported by a resonant spring118.

The inner stator134may be configured by stacking a plurality of laminations on the outer circumferential surface of the body portion121of the frame120in the circumferential direction.

One side of the magnet135may be coupled to and supported by the magnet frame136. The magnet frame136has a substantially cylindrical shape and may be disposed to be inserted into a space between the outer stator131and the inner stator134. The magnet frame136may be coupled to the rear side of the piston150to move together with the piston150.

As an example, a rear end of the magnet frame136is bent and extended inward radially to form a first coupling portion136a,and the first coupling portion136amay be coupled to a third flange portion153formed behind the piston150. The first coupling portion136aof the magnet frame136and the third flange portion153of the piston150may be coupled through a mechanical coupling member.

Further, a fourth flange portion161ain front of the intake muffler161may be interposed between the third flange portion153of the piston150and the first coupling portion136aof the magnet frame136. Thus, the piston150, the muffler unit160, and the magnet135can linearly reciprocate together in a combined state.

When a current is applied to the drive unit130, a magnetic flux may be formed in the winding coil, and an electromagnetic force may occur by an interaction between the magnetic flux formed in the winding coil of the outer stator131and a magnetic flux formed by the permanent magnet of the magnet135to move the magnet135. At the same time as the axially reciprocating movement of the magnet135, the piston150connected to the magnet frame136may also axially reciprocate integrally with the magnet135.

The linear compressor100may include a plurality of sealing members that can increase a coupling force between the frame120and the components around the frame120.

For example, the plurality of sealing members may include a first sealing member that is interposed at a portion where the frame120and the discharge cover assembly180are coupled, and is inserted into an installation groove provided at the front end of the frame120, and a second sealing member that is provided at a portion where the frame120and the cylinder140are coupled, and is inserted into an installation groove provided at an outer surface of the cylinder140. The second sealing member can prevent the refrigerant of the gas groove125cbetween the inner circumferential surface of the frame120and the outer circumferential surface of the cylinder140from leaking to the outside, and can increase a coupling force between the frame120and the cylinder140. The plurality of sealing members may further include a third sealing member that is provided at a portion where the frame120and the inner stator134are coupled, and is inserted into an installation groove provided at the outer surface of the frame120. Here, the first to third sealing members may have a ring shape.

An operation of the linear compressor100described above is as follows.

First, when a current is applied to the drive unit130, a magnetic flux may be formed in the outer stator131by the current flowing in the coil132b.The magnetic flux formed in the outer stator131may generate an electromagnetic force, and the magnet135including the permanent magnet may linearly reciprocate by the generated electromagnetic force. The electromagnetic force may be alternately generated in a direction (forward direction) in which the piston150is directed toward a top dead center (TDC) during a compression stroke, and in a direction (rearward direction) in which the piston150is directed toward a bottom dead center (BDC) during an intake stroke. That is, the drive unit130may generate a thrust which is a force for pushing the magnet135and the piston150in a moving direction.

The piston150linearly reciprocating inside the cylinder140may repeatedly increase or reduce the volume of the compression space103.

When the piston150moves in a direction (rearward direction) of increasing the volume of the compression space103, a pressure of the compression space103may decrease. Hence, the intake valve155mounted in front of the piston150is opened, and the refrigerant remaining in the intake space102may be sucked into the compression space103along the intake port154. The intake stroke may be performed until the piston150is positioned in the bottom dead center by maximally increasing the volume of the compression space103.

The piston150reaching the bottom dead center may perform the compression stroke while switching its motion direction and moving in a direction (forward direction) of reducing the volume of the compression space103. As the pressure of the compression space103increases during the compression stroke, the sucked refrigerant may be compressed. When the pressure of the compression space103reaches a setting pressure, the discharge valve171is pushed out by the pressure of the compression space103and is opened from the cylinder140, and thus the refrigerant can be discharged into the discharge space104through a separation space. The compression stroke may continue while the piston150moves to the top dead center at which the volume of the compression space103is minimized.

As the intake stroke and the compression stroke of the piston150are repeated, the refrigerant introduced into the accommodation space101inside the linear compressor100through the intake pipe114may be introduced into the intake space102in the piston150by sequentially passing the intake guide116a,the intake muffler161, and the inner guide162, and the refrigerant of the intake space102may be introduced into the compression space103in the cylinder140during the intake stroke of the piston150. After the refrigerant of the compression space103is compressed and discharged into the discharge space104during the compression stroke of the piston150, the refrigerant may be discharged to the outside of the linear compressor100via the loop pipe115aand the discharge pipe115.

FIG.8is a cross-sectional perspective view of partial configuration of a linear compressor200according to a second embodiment of the present disclosure.FIG.9is a cross-sectional view of partial configuration of the linear compressor200according to the second embodiment of the present disclosure.

It can be understood that detailed configuration of the linear compressor200according to the second embodiment of the present disclosure illustrated inFIGS.8and9, in which the description is omitted later, is the same as detailed configuration of the linear compressor100according to the first embodiment of the present disclosure illustrated inFIGS.2to7.

The linear compressor200may include a muffler unit260. The muffler unit260may be disposed in a piston250. The muffler unit260may be formed as a single member, or may be formed by combining a plurality of members. The muffler unit260may be coupled to the piston250to axially reciprocate together with the piston250. The muffler unit260may reduce a noise generated in a compression space203.

Referring toFIGS.8and9, the muffler unit260may include a guide member261and a muffler member262. The muffler member262may be disposed at the rear of the guide member261. Noise spaces206aand206bmay be formed between the rear of the guide member261and the front of the muffler member262.

The linear compressor200may include an elastic body291. An outer end of the elastic body291may be disposed inside the piston250. The piston250may be flexibly tilted from a supporter219through the elastic body291. An inclination of the elastic body291may be variably changed with respect to the supporter219. A detailed description thereof may be the same as described above with respect to the linear compressor100according to the first embodiment of the present disclosure.

The outer end of the elastic body291may be coupled to an inner circumferential surface of a sliding portion252. A method of coupling the elastic body291to the inner circumferential surface of the sliding portion252may be the same as described above with reference toFIG.6. A radially central area of the elastic body291may be coupled to one side of a rod292. The elastic body291and one side of the rod292may be screw-coupled as described above. The rod292may be disposed inside a second internal flow path205b.

The guide member261may be disposed in front of the elastic body291. Specifically, a rear end of the guide member261may be disposed in close contact with a front surface of the elastic body291. The muffler member262may be disposed at the rear of the elastic body291. Specifically, a front end of the muffler member262may be disposed in close contact with a rear surface of the elastic body291. In this case, the elastic body291may be disposed at a position Where the noise spaces206aand206bare formed.

The muffler unit260may include internal flow paths205aand205b.The internal flow paths205aand205bmay be turned inside the muffler unit260. The internal flow paths205aand205bmay extend axially. Front ends of the internal flow paths205aand205bmay communicate with an intake space202formed inside the piston250, and rear ends of the internal flow paths205aand205bmay communicate with an accommodation space201formed inside a casing210.

The internal flow paths205aand205bmay include a first internal flow path205aand a second internal flow path205b.The first internal flow path205aand the second internal flow path205bmay be axially partitioned by the elastic body291. The first internal flow path205aand the second internal flow path205bmay communicate with each other by a plurality of first flow holes291aformed in the elastic body291.

The muffler unit260may form the noise spaces206aand206b.The noise spaces206aand206bmay be formed on radially outer sides of the internal flow paths205aand205b.The internal flow paths205aand205band the noise spaces206aand206bmay communicate with each other. A radius of inner circumferential surfaces of the noise spaces206aand206bmay be greater than a radius of inner circumferential surfaces of the internal flow paths205aand205b.

The noise spaces206aand206bmay include a first noise space206aand a second noise space206b.The first noise space206aand the second noise space206bmay be axially partitioned by the elastic body291. Specifically, the first internal flow path205amay extend to the front of the elastic body291, and the second internal flow path205bmay extend to the rear of the elastic body291. The first noise space206amay be formed. radially outward in a rear end portion of the first internal flow path205a.The second noise space206bmay be formed radially outward in a front end portion of the second internal flow path205b.

When the noise spaces206aand206bare divided into the first noise space206aand the second noise space206b,a noise reduction effect may increase. Specifically, a compression noise generated in the compression space203and the piston may move rearward along the first internal flow path205a.The compression noise moving rearward along the first internal flow path205amay be radiated to the first noise space206a.The compression noise radiated to the first noise space206amay be radiated to the second noise space206bthrough the plurality of first flow holes291aformed in the elastic body291. Since a flow path cross-sectional area of the plurality of first flow holes291ais smaller than an induction cross-sectional area of the first noise space206aand the second noise space206b,the present disclosure can achieve the same effect as that obtained when the two noise spaces206aand206bare formed. The process of reducing the compression noise by the noise spaces206aand206bmay be the same as described above with respect to the muffler unit160of the linear compressor100according to the first embodiment of the present disclosure.

Unlike the configuration illustrated inFIGS.8and9, the elastic body291may be coupled to the inner circumferential surfaces of the noise spaces206aand206b.The elastic body291may be disposed between the guide member261and the muffler member262before the guide member261and the muffler member262are coupled to each other, and then the rear end of the guide member261and the front end of the muffler member262may be coupled. In this case, after the elastic body291is first assembled to the muffler unit260, the muffler unit260may be coupled to the piston250.

Alternatively, either the guide member261or the muffler member262and the elastic body291may be integrally formed, and the muffler unit260may be formed integrally and at the same time the elastic body291may also be formed integrally with the muffler unit260.

FIG.10is a cross-sectional perspective view of partial configuration of a linear compressor300according to a third embodiment of the present disclosure.FIG.11is a cross-sectional view of partial configuration of the linear compressor300according to the third embodiment of the present disclosure.

It can be understood that detailed configuration of the linear compressor300according to the second embodiment of the present disclosure illustrated inFIGS.10and11, in which the description is omitted later, is the same as detailed configuration of the linear compressor100according to the first embodiment of the present disclosure illustrated inFIGS.2to7.

The linear compressor300may include an elastic body391. The elastic body391may be disposed inside a piston350. The elastic body391may be disposed adjacent to a rear end of a sliding portion352. In this case, a method of coupling the elastic body391to an inner circumferential surface of the sliding portion352may be the same as described above with reference toFIG.6. When the elastic body391is disposed adjacent to the rear end of the sliding portion352, there is no need to seat the elastic body391to the depth of the piston350. Therefore, a manufacturing process can be facilitated. In addition, a replacement operation of the elastic body391for maintenance can be facilitated.

The linear compressor300may include a muffler unit360. The muffler unit360may be disposed in front of the elastic body391. Since a rod392of the linear compressor300according to the third embodiment of the present disclosure is formed only up to a portion where the elastic body391is disposed, the rod392may not be formed inside an internal flow path305formed inside the muffler unit360. In this case, since there is no part of the internal flow path305occupied by the rod392, a refrigerant passing through a plurality of first flow holes391aformed in the elastic body391can pass through the internal flow path305of the muffler unit360and can be smoothly introduced into an intake space302.

As described above, the elastic body391may be coupled to various positions of the sliding portion352. The tilting flexibility of the piston350may vary depending on the coupling position of the elastic body391and the sliding portion352, and a rotation point of the piston350may vary. Accordingly, the present disclosure can adjust the coupling position of the elastic body391and can control the tilting flexibility and the rotation point of the piston350.

FIG.12is a perspective view illustrating one side of a rod492of an elastic body491and the elastic body491in a linear compressor according to a fourth embodiment of the present disclosure.

It can be understood that detailed configuration of the linear compressor400according to the fourth embodiment of the present disclosure illustrated inFIG.12, in which the description is omitted later, is the same as detailed configuration of the linear compressor100according to the first embodiment of the present disclosure illustrated inFIGS.2to7.

The linear compressor400may include the elastic body491. The elastic body491may be formed in a shape in which a plurality of elastic units491aare radially disposed, and respective radially outer portions of the plurality of elastic units491aare separated from each other. That is, when viewed axially, the elastic body491may be formed in a propeller shape.

Since the respective radially outer portions of the plurality of elastic units491aare separated from each other, it may be easy to press-fit when inserted from the rear of a piston450. Specifically, a radius of the elastic body491may be greater than a radius of a portion of an inner circumferential surface of a sliding portion452in which a groove493is not formed. In this instance, when the elastic body491is disposed in the rear of the piston450in a state in which the rod492is coupled to a radially central area of the elastic body491, and then the elastic body491is press-fitted into the sliding portion452by pushing the rod492, an outer portion of the elastic body491may be introduced into the inside of the sliding portion452while slightly bending rearward. When the elastic body491is press-fitted up to the position where the groove493is formed, the outer portion of the elastic body491may be seated in the groove493, and the elastic body491may be fixed to the piston450.

In order to ensure proper elasticity of the elastic body491, each of the plurality of elastic units491amay be formed in a spiral shape away from the axis. Alternatively, based on an internal structure of the piston450, a coupling relationship between the piston450and the elastic body491, and the like, the plurality of elastic units491amay be formed in various shapes such as straight extending radially outward about the axis.

A refrigerant may flow into each space between the plurality of elastic units491a.That is, it can be understood that each space between the plurality of elastic units491aperforms the same role as the first flow hole191aof the linear compressor100according to the first embodiment of the present disclosure.

FIG.13is a cross-sectional perspective view of partial configuration of a linear compressor500according to a fifth embodiment of the present disclosure.FIG.14is an exploded perspective view of partial configuration of the linear compressor500according to the fifth embodiment of the present disclosure.FIG.15is a cross-sectional view of partial configuration of the linear compressor500according to the fifth embodiment of the present disclosure.

It can be understood that detailed configuration of the linear compressor500according to the fifth embodiment of the present disclosure illustrated inFIGS.13to15, in which the description is omitted later, is the same as detailed configuration of the linear compressor100according to the first embodiment of the present disclosure illustrated inFIGS.2to7.

The linear compressor500may include a piston550. The piston550may include an elastic portion551and a sliding portion552extending rearward from a radially outer edge of the elastic portion551. The piston550may be connected to a supporter519by a rod592to reciprocate axially inside a cylinder540.

The linear compressor500may include the elastic portion551. A radially central area of the elastic portion551may be coupled to one side of the rod592. The piston550may be elastically supported axially and/or radially by the elastic portion551coupled to one side of the rod592.

Referring toFIGS.13and14, the elastic portion551may extend outward radially about an axis. The elastic portion551may be radially disposed and may be a leaf spring formed in a disk shape.

When the elastic portion551is formed of the leaf spring, radial elasticity may be stronger than axial elasticity. When the elastic portion551has the stronger radial elasticity than the axial elasticity, the eccentricity of the supporter519with respect to the elastic portion551can be minimized. When the axial elasticity of the elastic portion551is weak, flexible tilting may be possible.

Specifically, the supporter519may be elastically supported by a plurality of resonant springs518coupled to a spring seat portion519c.The supporter519may be a mover that is coupled to a magnet frame536, to which a magnet535is coupled, and reciprocates axially. In this case, the alignment between the axis of the linear compressor500and the axis of the supporter519may be misaligned. When the piston550is not flexibly tilted with respect to the supporter519, the axial alignment of the piston550with respect to the cylinder540may also be misaligned. Therefore, a friction and/or contact may occur between the piston550and the cylinder540. The friction may wear and damage the components.

When the elastic portion551is formed of the leaf spring, a tilting freedom of the piston550with respect to the supporter519may increase. Therefore, the piston550can easily maintain the axial alignment by the gas bearing on the inside of the cylinder540. At the same time as this, since the eccentricity of the supporter519and/or the magnet frame536with respect to the piston550can be reduced, a gap in a drive unit530can be kept relatively constant. Through this, since the contact and/or friction between the components can be reduced, a damage of the component and noise generation can be prevented. Hence, the reliability of the linear compressor500can be improved, and the efficiency of the linear compressor500can also be improved.

The elastic portion551may include a plurality of fourth flow holes554. The refrigerant may be introduced into a compression space503firmed in front of the piston550through the plurality of fourth flow holes554. That is, it can be understood that the plurality of fourth flow holes554perform the same role as the intake port154of the linear compressor100according to the first embodiment of the present disclosure.

The refrigerant introduced into the compression space503through the plurality of fourth flow holes554may be compressed by a front surface of the elastic portion551and may be discharged to a discharge space504. That is, it can be understood that the elastic portion551performs the same role as the elastic body191of the linear compressor100according to the first embodiment of the present disclosure and also performs the same role as the head portion151of the piston150of the linear compressor100.

The plurality of fourth flow holes554may be disposed radially about the axis. Each of the plurality of fourth flow holes554may be formed in a spiral shape away from the axis. The plurality of fourth flow holes554may be formed in various shapes so as to secure the proper elasticity of the elastic portion551. The plurality of fourth flow holes554may be understood as slits formed between elastic elements of the leaf spring. Accordingly, the elasticity of the elastic portion551may be controlled by adjusting the shape, the size, or the number of the plurality of fourth flow holes554.

Alternatively, in order for an intake valve555to stably open and close elastically the plurality of fourth flow holes554, each of the plurality of fourth flow holes554may be formed in a substantially fan shape.

Since the elastic portion551has to be elastically deformed unlike the head portion151of the linear compressor100according to the first embodiment of the present disclosure, an axial length of the elastic portion551may be less than an axial length of the head portion151of the linear compressor100according to the first embodiment of the present disclosure.

As described above, the linear compressor500according to the fifth embodiment of the present disclosure can reduce the manufacturing cost and simplify the manufacturing process since a front end of the piston550is formed of arm elastic material without the separate elastic body191for flexible tilting of the piston550.

The linear compressor500may include the rod592. The rod592may extend axially. The rod592may be disposed inside an internal flow path505extending axially inside a muffler unit560. One end of the rod592may be coupled to the radially central area of the elastic portion551, and other end may be coupled to a radially central area of a plate519b.An elastic force of the resonant spring518may be transmitted to the rod592through the supporter519. The elastic force transmitted to the rod592may be transmitted to the piston550through the elastic portion551.

The linear compressor500may include the intake valve555. The intake valve555may be coupled to the front of the elastic portion551. The intake valve555may be configured to cover fronts of the plurality of fourth flow holes554. The intake valve555may be formed to be slightly larger than the plurality of fourth flow holes554.

For example, when each of the plurality of fourth flow holes554is formed in a spiral shape away from the axis, the intake valve555may extend to a position where the plurality of fourth flow holes554are formed. In this instance, the intake valve555may be configured such that a portion axially extended to cover all the plurality of fourth flow holes554is formed in a shape corresponding to the shape of the plurality of fourth flow holes554and is formed to be slightly larger than the plurality of fourth flow holes554. That is, it may be understood that the intake valve555is formed in a shape similar to a fan blade when viewed axially.

The intake valve555may selectively open and close the plurality of fourth flow holes554formed in the elastic portion551forming one surface of the compression space503. That is, the intake valve555may be elastically deformed to open the plurality of fourth flow holes554by a pressure of the refrigerant that passes through the plurality of fourth flow holes554and is introduced into the compression space503.

The elastic portion551and the rod592may be rigidly coupled. When the rod592is formed of the rigid material and is rigidly coupled to the elastic portion551, an elastically deformed portion is limited to the elastic portion551. Therefore, a rotation point of the piston550can be easily designed. In addition, since the flexibility of the tilting of the piston550can be adjusted by forming the elastic portion551with the proper elasticity to a behavior of the piston550, the behavior of the piston550can be easily controlled.

The linear compressor500may include a coupling member556. The coupling member556may couple the intake valve555and the piston550to a front end of the rod592. That is, the intake valve555may be coupled to the front surface of the elastic portion551by the coupling member556, and the elastic portion551may be coupled to one side of the rod592.

Specifically, the coupling member556may axially pass through a radially central area of the intake valve555and the radially central area of the elastic portion551and may be coupled to one side of the rod592. The rod592may include a second coupling groove592a. The second coupling groove592amay be formed on one side of the rod592. The second coupling groove592amay be formed of a female screw. The coupling member556may be formed of a male screw. The coupling member556may be screw-coupled to the second coupling groove592a.

As described above, since the intake valve555and the elastic portion551can be simultaneously coupled to one side of the rod592through one coupling member556, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Alternatively, the elastic portion551and one side of the rod592may be integrally formed. When the elastic portion551and the rod592are integrally formed, the present disclosure can prevent the problem such as noise generation due to a gap that may occur at the coupling portion between the elastic body191and the rod592.

Some embodiments or other embodiments of the present disclosure described above are not exclusive or distinct from each other. Some embodiments or other embodiments of the present disclosure described above can be used together or combined in configuration or function.

For example, configuration “A” described in an embodiment and/or the drawings and configuration “B” described in another embodiment and/or the drawings can be combined with each other. That is, even if the combination between the configurations is not directly described, the combination is possible except in cases where it is described that it is impossible to combine.

The above detailed description is merely an example and is not to be considered as limiting the present disclosure. The scope of the present disclosure should be determined by rational interpretation of the appended claims, and all variations within the equivalent scope of the present disclosure are included in the scope of the present disclosure.