Patent ID: 12228120

DETAILED DESCRIPTION

Reference will now be made in detail to implementations 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.

FIG.1is a perspective view showing an example of a linear compressor.

Referring toFIG.1, in some implementations, a linear compressor100can include a shell111and shell covers112and113coupled to the shell111. In a broad sense, the shell covers112and113can be understood as one configuration of the shell111.

In some examples, legs20can be coupled to a lower side of the shell111. The legs20can be coupled to a base of a product on which the linear compressor100is mounted. For example, the product can include a refrigerator, and the base can include a machine room base of the refrigerator. As another example, the product can include an outdoor unit of an air conditioner, and the base can include a base of the outdoor unit.

The shell111can have a substantially cylindrical shape and can 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 compressor100can coincide with a central axis of a cylinder140and a piston150that constitute the main body of the linear compressor100.

A terminal30can be installed on an outer surface of the shell111. The terminal30can transmit external electric power to a drive unit130of the linear compressor100. More specifically, the terminal30can be connected to a lead line of a coil132b.

A bracket31can be installed on the outside of the terminal30. The bracket31can include a plurality of brackets surrounding the terminal30. The bracket31can perform a function of protecting the terminal30from an external impact, etc.

Both sides of the shell111can be opened. The shell covers112and113can be coupled to both sides of the opened shell111. More specifically, the shell covers112and113can 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 shell111can 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 covers112and113can 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 compressor100can include a plurality of pipes114,115, and40that are included in the shell111or the shell covers112and113and can suction, discharge, or inject the refrigerant.

The plurality of pipes114,115, and40can include an intake pipe114that allows the refrigerant to be suctioned 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 pipe114can be coupled to the first shell cover112. The refrigerant can be suctioned into the linear compressor100along the axial direction through the intake pipe114.

The discharge pipe115can be coupled to an outer circumferential surface of the shell111. The refrigerant suctioned through the intake pipe114can be compressed while flowing in the axial direction. The compressed refrigerant can be discharged through the discharge pipe115. The discharge pipe115can be disposed closer to the second shell cover113than to the first shell cover112.

The supplementary pipe40can be coupled to the outer circumferential surface of the shell111. A worker can inject the refrigerant into the linear compressor100through the supplementary pipe40.

The supplementary pipe40can be coupled to the shell111at a different height from the discharge pipe115in order to prevent interference with the discharge pipe115. Herein, the height can 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 cover113can be positioned adjacently. In other words, at least a portion of the second shell cover113can 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 pipe40can be 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 can be reduced to vaporize the refrigerant, and an oil contained in the refrigerant can 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 can be understood as a working oil present in a cooling system.

FIG.2is a cross-sectional view illustrating an example structure of the linear compressor100.

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

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

Referring toFIG.2, the linear compressor100can include a casing110and a main body received in the casing110. The main body of the linear compressor100can 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. For example, the cylinder140and the piston150can be referred to as compression units140and150.

The linear compressor100can include a bearing for reducing a friction between the cylinder140and the piston150. For instance, the bearing can include an oil bearing or a gas bearing. Alternatively, a mechanical bearing can be used as the bearing.

The main body of the linear compressor100can be elastically supported by support springs116and117installed at both ends in the casing110. The support springs116and117can 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 springs116and117can 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 casing110can define a sealed space. The sealed space can include an accommodation space101in which the suctioned 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 suctioned from the intake pipe114connected to the rear side of the casing110can be filled in the accommodation space101, and the refrigerant in the intake space102communicating with the accommodation space101can 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 casing110can 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. For instance, 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 cover113can be formed as one body with the shell11.

The casing110can 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 cover112can be coupled to the shell111in order to seal the rear side of the shell111, and the intake pipe114can be inserted and coupled to the center of the first shell cover112.

The rear side of the main body of the linear compressor100can be elastically supported by the first support spring116in the radial direction of the first shell cover112.

The first support spring116can include a circular leaf spring. An edge portion of the first support spring116can be elastically supported by a support bracket123ain a forward direction with respect to a back cover123. An opened center portion of the first support spring116can be supported by an intake guide116ain a rearward direction with respect to the first shell cover112.

The intake guide116acan have a through passage formed therein. The intake guide116acan be formed in a cylindrical shape. A front outer circumferential surface of the intake guide116acan be coupled to a central opening of the first support spring116, and a rear end of the intake guide116acan be supported by the first shell cover112. In this instance, a separate intake support member116bcan be interposed between the intake guide116aand an inner surface of the first shell cover112.

A rear side of the intake guide116acan communicate with the intake pipe114, and the refrigerant suctioned through the intake pipe114can pass through the intake guide116aand can be smoothly introduced into a first muffler unit160to be described below.

A damping member116ccan be disposed between the intake guide116aand the intake support member116b. The damping member116ccan be formed of a rubber material or the like. Hence, a vibration that can occur in the process of suctioning the refrigerant through the intake pipe114can be prevented from being transmitted to the first shell cover112.

The second shell cover113can be coupled to the shell111to seal the front side of the shell111, and the discharge pipe115can be inserted and coupled through a loop pipe115a. The refrigerant discharged from the compression space103can pass through a discharge cover assembly180and then can be discharged into the refrigeration cycle through the loop pipe115aand the discharge pipe115.

A front side of the main body of the compressor100can be elastically supported by the second support spring117in the radial direction of the shell111or the second shell cover113.

The second support spring117can include a circular leaf spring. An opened center portion of the second support spring117can be supported by a first support guide117bin a rearward direction with respect to the discharge cover assembly180. An edge of the second support spring117can be supported by a support bracket117ain a forward direction with respect to an inner surface of the shell111or the inner circumferential surface of the shell111adjacent to the second shell cover113.

In some examples, unlikeFIG.2, the edge of the second support spring117can 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 coupled to the second shell cover113.

The first support guide117bcan be formed in a cylindrical shape. A cross section of the first support guide117bcan have a plurality of diameters. A front side of the first support guide117bcan be inserted into a central opening of the second support spring117, and a rear side of the first support guide117bcan be connected to the discharge cover assembly180. A support cover117ccan be coupled to the front side of the first support guide117bwith the second support spring117interposed therebetween. A cup-shaped second support guide117dthat is recessed rearward can be coupled to the front side of the support cover117c. A cup-shaped third support guide117ethat corresponds to the second support guide117dand is recessed forward can be coupled to the inside of the second shell cover113. The second support guide117dcan be inserted into the third support guide117eand can be supported in the axial direction and/or the radial direction. In this instance, a gap can be formed between the second support guide117dand the third support guide117e.

The frame120can 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 frame120can be elastically supported with respect to the casing110by the first and second support springs116and117together with the drive unit130and the cylinder140.

The body portion121can wrap the outer circumferential surface of the cylinder140. The body portion121can be formed in a cylindrical shape. The first flange portion122can extend from a front end of the body portion121in the radial direction.

The cylinder140can be coupled to an inner circumferential surface of the body portion121. An inner stator134can be coupled to an outer circumferential surface of the body portion121. For example, the cylinder140can be pressed and fitted to the inner circumferential surface of the body portion121, and the inner stator134can be fixed using a separate fixing ring.

An outer stator131can be coupled to a rear surface of the first flange portion122, and the discharge cover assembly180can be coupled to a front surface of the first flange portion122. For example, the outer stator131and the discharge cover assembly180can be fixed through a mechanical coupling member.

On one side of the front surface of the first flange portion122, a bearing inlet groove125aforming a part of the gas bearing can be formed, a bearing communication hole125bpenetrating from the bearing inlet groove125ato the inner circumferential surface of the body portion121can be formed, and a gas groove125ccommunicating with the bearing communication hole125bcan be formed on the inner circumferential surface of the body portion121.

The bearing inlet groove125acan be recessed to a predetermined depth along the axial direction. The bearing communication hole125bis a hole having a smaller cross-sectional area than the bearing inlet groove125aand can be inclined toward the inner circumferential surface or the inside surface of the body portion121. The gas groove125ccan 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 groove125ccan 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 groove125ccan be formed on the outer circumferential surface of the cylinder140. The gas inlet142forms a kind of nozzle in the gas bearing.

The frame120and the cylinder140can be formed of aluminum or an aluminum alloy material.

The cylinder140can be formed in a cylindrical shape in which both ends are opened. The piston150can be inserted through a rear end of the cylinder140. A front end of the cylinder140can be closed via a discharge valve assembly170. The compression space103can be formed between the cylinder140, a front end of the piston150, and the discharge valve assembly170. For example, the front end of the piston150can 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 space103can be compressed while the piston150moves forward, and can be discharged through the discharge valve assembly170.

The cylinder140can include a second flange portion141disposed at the front end. The second flange portion141can bend to the outside of the cylinder140. The second flange portion141can extend in an outer circumferential direction of the cylinder140. The second flange portion141of the cylinder140can be coupled to the frame120. For example, the front end of the frame120can include a flange groove corresponding to the second flange portion141of the cylinder140, and the second flange portion141of the cylinder140can be inserted into the flange groove and coupled through a coupling member.

In some implementations, a gas bearing can be provided to supply a discharge gas to a gap between the outer circumferential surface of the piston150and the outer circumferential surface of the cylinder140and lubricate between the cylinder140and the piston150with gas. The discharge gas supplied between the cylinder140and the piston150can provide a levitation force to the piston150to reduce a friction generated between the piston150and the cylinder140.

For example, the cylinder140can include the gas inlet142. The gas inlet142can communicate with the gas groove125cformed on the inner circumferential surface of the body portion121. The gas inlet142can pass through the cylinder140in the radial direction. The gas inlet142can 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 groove125ccan be formed on the outer circumferential surface of the cylinder140in consideration of the convenience of processing.

An entrance of the gas inlet142can be formed relatively widely, and an exit of the gas inlet142can be formed as a fine through hole to serve as a nozzle. The entrance of the gas inlet142can further include a filter blocking the inflow of foreign matter. The filter can be a metal mesh filter, or can be formed by winding a member such as fine thread.

The plurality of gas inlets142can be independently formed. Alternatively, the entrance of the gas inlet142can be formed as an annular groove, and a plurality of exits can be formed along the annular groove at regular intervals. The gas inlet142can be formed only at the front side based on the axial direction center of the cylinder140. On the contrary, the gas inlet142can 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 piston150can include a head portion151and a guide portion152. The head portion151can be formed in a disc shape. The head portion151can be partially open. The head portion151can partition the compression space103. The guide portion152can extend rearward from an outer circumferential surface of the head portion151. The guide portion152can be formed in a cylindrical shape. The inside of the guide portion152can be empty, and a front of the guide portion152can be partially sealed by the head portion151. A rear of the guide portion152can be opened and connected to the first muffler unit160. The head portion151can be provided as a separate member coupled to the guide portion152. Alternatively, the head portion151and the guide portion152can be formed as one body.

The piston150can include an intake port154. The intake port154can pass through the head portion151. The intake port154can communicate with the intake space102and the compression space103inside the piston150. For example, the refrigerant flowing from the accommodation space101to the intake space102in the piston150can pass through the intake port154and can be suctioned into the compression space103between the piston150and the cylinder140.

The intake port154can extend in the axial direction of the piston150. The intake port154can be inclined in the axial direction of the piston150. For example, the intake port154can 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 port154can be formed in a circular shape. The intake port154can have a constant inner diameter. In contrast, the intake port154can be formed as a long hole in which an opening extends in the radial direction of the head portion151, or can be formed such that the inner diameter becomes larger as it goes to the rear.

The plurality of intake ports154can 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 space103can be equipped with an intake valve155for selectively opening and closing the intake port154. The intake valve155can operate by elastic deformation to open or close the intake port154. That is, the intake valve155can be elastically deformed to open the intake port154by the pressure of the refrigerant flowing into the compression space103through the intake port154. The intake valve155can be a lead valve, but is not limited thereto and can be variously changed. The piston150can be connected to a mover135. The mover135can reciprocate forward and backward according to the movement of the piston150. The inner stator134and the cylinder140can be disposed between the mover135and the piston150. The mover135and the piston150can be connected to each other by a magnet frame136that is formed by detouring the cylinder140and the inner stator134to the rear.

The first muffler unit160can be coupled to the rear of the piston150to reduce a noise generated in the process of suctioning the refrigerant into the piston150. The refrigerant suctioned through the intake pipe114can flow into the intake space102in the piston150via the first muffler unit160.

The first muffler unit160can include a first intake muffler161communicating with the accommodation space101of the casing110, and an inner guide162that is connected to a front of the first intake muffler161and guides the refrigerant to the intake port154.

The first intake muffler161can be positioned behind the piston150. A rear opening of the first intake muffler161can be disposed adjacent to the intake pipe114, and a front end of the first intake muffler161can be coupled to the rear of the piston150. The first intake muffler161can have a flow path formed in the axial direction to guide the refrigerant in the accommodation space101to the intake space102inside the piston150.

The inside of the first intake muffler161can include a plurality of noise spaces partitioned by a baffle. The first intake muffler161can be formed by combining two or more members. For example, a second intake muffler can be press-coupled to the inside of a first intake muffler to form a plurality of noise spaces. In addition, the first intake muffler161can be formed of a plastic material in consideration of weight or insulation property.

One side of the inner guide162can communicate with the noise space of the first intake muffler161, and other side can be deeply inserted into the piston150. The inner guide162can be formed in a pipe shape. Both ends of the inner guide162can have the same inner diameter. The inner guide162can be formed in a cylindrical shape. Alternatively, an inner diameter of a front end that is a discharge side of the inner guide162can be greater than an inner diameter of a rear end opposite the front end.

The first intake muffler161and the inner guide162can be provided in various shapes and can adjust the pressure of the refrigerant passing through the first muffler unit160. The first intake muffler161and the inner guide162can be formed as one body.

The discharge valve assembly170can 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 assembly170can selectively discharge the compressed refrigerant in the compression space103. For instance, the compression space103refers to a space defined between the intake valve155and the discharge valve171.

The discharge valve171can be disposed to be supportable on the front surface of the cylinder140. The discharge valve171can selectively open and close the front opening of the cylinder140. The discharge valve171can operate by elastic deformation to open or close the compression space103. The discharge valve171can 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 space103can maintain a sealed state while the discharge valve171is supported on the front surface of the cylinder140, and the compressed refrigerant of the compression space103can be discharged into an opened space in a state where the discharge valve171is spaced apart from the front surface of the cylinder140. The discharge valve171can be a lead valve, but is not limited thereto and can be variously changed.

The valve spring172can be provided between the discharge valve171and the discharge cover assembly180to provide an elastic force in the axial direction. The valve spring172can be provided as a compression coil spring, or can 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 spring172can open the discharge valve171while deforming forward, and the refrigerant can 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 suctioned 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 assembly180can be coupled to a front of the first flange portion122of the frame120while receiving the discharge valve assembly170. For example, the discharge cover assembly180can be coupled to the first flange portion122through a mechanical coupling member.

An O-ring166can 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 assembly180can be formed of a thermally conductive material. Therefore, when a high temperature refrigerant is introduced into the discharge cover assembly180, heat of the refrigerant can be transferred to the casing110through the discharge cover assembly180and dissipated to the outside of the compressor.

The discharge cover assembly180can include one discharge cover, or can 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 space104can include a plurality of spaces partitioned by the respective discharge covers. The plurality of spaces can be disposed in a front-rear direction and can communicate with each other.

For example, when there are three discharge covers, the discharge space104can 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 space104acan selectively communicate with the compression space103by the discharge valve171, the second discharge space104bcan communicate with the first discharge space104a, and the third discharge space104ccan 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 unit130can 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 mover135disposed between the outer stator131and the inner stator134.

The outer stator131can be coupled to the rear of the first flange portion122of the frame120, and the inner stator134can be coupled to the outer circumferential surface of the body portion121of the frame120. The inner stator134can be spaced apart from the inside of the outer stator131, and the mover135can be disposed in a space between the outer stator131and the inner stator134.

The outer stator131can be equipped with a winding coil, and the mover135can include a permanent magnet. The permanent magnet can be comprised of a single magnet with one pole or configured by combining a plurality of magnets with three poles.

The outer stator131can 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 body132can include a hollow cylindrical bobbin132aand a coil132bwound in a circumferential direction of the bobbin132a. A cross section of the coil132bcan be formed in a circular or polygonal shape and, for example, can have a hexagonal shape. In the stator core133, a plurality of lamination sheets can be laminated radially, or a plurality of lamination blocks can be laminated along the circumferential direction.

The front side of the outer stator131can be supported by the first flange portion122of the frame120, and the rear side thereof can be supported by a stator cover137. For example, the stator cover137can be provided in a hollow disc shape, a front surface of the stator cover137can be supported by the outer stator131, and a rear surface thereof can be supported by a resonant spring118.

The inner stator134can 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 mover135can be coupled to and supported by the magnet frame136. The magnet frame136has a substantially cylindrical shape and can be disposed to be inserted into a space between the outer stator131and the inner stator134. The magnet frame136can 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 in the radial direction to form a first coupling portion136a, and the first coupling portion136acan be coupled to a third flange portion153formed behind the piston150. The first coupling portion136aof the magnet frame136and the third flange portion153of the piston150can be coupled through a mechanical coupling member.

A fourth flange portion161aformed in front of the first intake muffler161and a fifth flange portion162aformed in rear of the inner guide162can be interposed between the third flange portion153of the piston150and the first coupling portion136aof the magnet frame136. Thus, the piston150, the first muffler unit160, and the mover135can linearly reciprocate together in a combined state.

When a current is applied to the drive unit130, a magnetic flux can be formed in the winding coil, and an electromagnetic force can 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 mover135to move the mover135. At the same time as the reciprocating movement of the mover135in the axial direction, the piston150connected to the magnet frame136can also reciprocate integrally with the mover135in the axial direction.

The drive unit130and the compression units140and150can be supported by the support springs116and117and the resonant spring118in the axial direction.

The resonant spring118amplifies the vibration implemented by the reciprocating motion of the mover135and the piston150and thus can achieve an effective compression of the refrigerant. More specifically, the resonant spring118can be adjusted to a frequency corresponding to a natural frequency of the piston150and can allow the piston150to perform a resonant motion. Further, the resonant spring118generates a stable movement of the piston150and thus can reduce the generation of vibration and noise.

The resonant spring118can be a coil spring extending in the axial direction. Both ends of the resonant spring118can be connected to a vibrating body and a fixed body, respectively. For example, one end of the resonant spring118can be connected to the magnet frame136, and the other end can be connected to the back cover123. Therefore, the resonant spring118can be elastically deformed between the vibrating body vibrating at one end and the fixed body fixed to the other end.

A natural frequency of the resonant spring118can be designed to match a resonant frequency of the mover135and the piston150during the operation of the compressor100, thereby amplifying the reciprocating motion of the piston150. However, because the back cover123provided as the fixing body is elastically supported by the first support spring116in the casing110, the back cover123may not be strictly fixed.

The resonant spring118can include a first resonant spring118asupported on the rear side and a second resonant spring118bsupported on the front side based on a spring supporter119.

The spring supporter119can include a body portion119asurrounding the first intake muffler161, a second coupling portion119bthat is bent from a front of the body portion119ain the inward radial direction, and a support portion119cthat is bent from the rear of the body portion119ain the outward radial direction.

A front surface of the second coupling portion119bof the spring supporter119can be supported by the first coupling portion136aof the magnet frame136. The second coupling portion119bof the spring supporter119can be coupled to the piston150. An inner diameter of the second coupling portion119bof the spring supporter119can cover an outer diameter of the first intake muffler161. For example, the second coupling portion119bof the spring supporter119, the first coupling portion136aof the magnet frame136, and the third flange portion153of the piston150can be sequentially disposed and then integrally coupled through a mechanical member. In this instance, the description, that the fourth flange portion161aand the fifth flange portion162aof the first intake muffler161can be interposed between the third flange portion153of the piston150and the first coupling portion136aof the magnet frame136and they can be fixed together, is the same as that described above.

The first resonant spring118acan be disposed between a front surface of the back cover123and a rear surface of the spring supporter119. The second resonant spring118bcan be disposed between a rear surface of the stator cover137and a front surface of the spring supporter119.

A plurality of first and second resonant springs118aand118bcan be disposed in the circumferential direction of the central axis. The first resonant springs118aand the second resonant springs118bcan be disposed parallel to each other in the axial direction, or can be alternately disposed. The first and second resonant springs118aand118bcan be disposed at regular intervals in the radial direction of the central axis. For example, three first resonant springs118aand three second resonant springs118bcan be provided and can be disposed at intervals of 120 degrees in the radial direction of the central axis.

The compressor100can 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 can 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 at which 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 can further include a third sealing member that is provided at a portion at which the frame120and the inner stator134are coupled and is inserted into an installation groove provided at the outer surface of the frame120. In some examples, the first to third sealing members can 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 can be formed in the outer stator131by the current flowing in the coil132b. The magnetic flux formed in the outer stator131can generate an electromagnetic force, and the mover135including the permanent magnet can linearly reciprocate by the generated electromagnetic force. The electromagnetic force can 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 unit130can generate a thrust which is a force for pushing the mover135and the piston150in a moving direction.

The piston150linearly reciprocating inside the cylinder140can 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 space103can decrease. Hence, the intake valve155mounted in front of the piston150is opened, and the refrigerant remaining in the intake space102can be suctioned into the compression space103along the intake port154. The intake stroke can 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 can 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 suctioned refrigerant can 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 the refrigerant can be discharged into the discharge space104through a separation space. The compression stroke can 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 compressor100through the intake pipe114can be introduced into the intake space102in the piston150by sequentially passing the intake guide116a, the first intake muffler161, and the inner guide162, and the refrigerant of the intake space102can 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 can be discharged to the outside of the compressor100via the loop pipe115aand the discharge pipe115.

FIGS.3and4are a perspective view showing an example of a muffler unit.FIG.5is an exploded perspective view of the muffler unit.FIG.6is a perspective view showing an example of a second intake muffler.FIG.7is a side view of the second intake muffler.FIG.8is a cross-sectional view of the second intake muffler.FIG.9is a front view of the second intake muffler.FIG.10is a rear view of the second intake muffler.FIGS.11and12are a perspective view showing an example of a muffler body.FIG.13is a front view of the muffler body.FIG.14is a rear view of the muffler body.FIGS.15and16are a perspective view showing an example of a muffler cover.FIG.17is a cross-sectional view showing an example of a piston, a muffler unit, and a back cover.FIG.18is a perspective view of the muffler unit and the back cover.FIG.19is a cross-sectional exploded perspective view of the muffler unit and the back cover.FIG.20is a rear view of the back cover.FIGS.21and22are a rear view of the back cover and the muffler unit.FIG.23is a perspective view showing an example of the piston, a spring supporter, a first resonant spring, the muffler unit, and the back cover.FIG.24is a block diagram showing an example of multiple resonators.FIG.25is a graph illustrating an example of a transmission loss (TL) per frequency in multiple resonators.FIG.26is a graph illustrating an example of an insertion loss (IL) depending on a frequency in a muffler unit according to a related art and a muffler unit.

Referring toFIGS.3to23, muffler units160and200of the linear compressor100can include a first muffler unit160and a second muffler unit200, but can be implemented except some of these components and does not exclude additional components.

In the present disclosure, the front refers to an axially front and the rear refers to an axially rear. More specifically, inFIG.2, the front can refer to a downward direction, and the rear can refer to an upward direction. InFIG.17, the front can refer to a left direction, and the rear can refer to a right direction. For example, the refrigerant in the cylinder is compressed in a direction from a rear side of the cylinder to a front side of the cylinder.

In some implementations, the first muffler unit160can include the first intake muffler161and the inner guide162.

The second muffler unit200can be coupled to an opening1230formed in a radially central area of the back cover123. The second muffler unit200can provide an expansion space in which noise is attenuated between the piston150and the back cover123. Through this, noise of the linear compressor100can be reduced by improving a performance of the muffler units160and200.

The second muffler unit200can include ribs2126,2130,2128,2144,2148,2224,2248,2236,2238, and2235protruding from an outer surface or an inner surface. It can be understood here that the outer surface includes a radially outer circumferential surface, a front surface, and a rear surface. Through this, the rigidity of the second muffler unit200can be improved.

The second muffler unit200can include a second intake muffler210, a muffler body220, and a muffler cover230, but can be implemented except some of these components and does not exclude additional components.

The second intake muffler210can communicate with the first intake muffler161. A diameter of a front end of the second intake muffler210can be larger than a diameter of a rear end of the first intake muffler161. As the piston150reciprocates axially, a rear area of the first intake muffler161coupled to the piston150can move axially inside the second intake muffler210.

The second intake muffler210can be coupled to the back cover123. More specifically, the second intake muffler210can be coupled to the opening1230.

The second intake muffler210can include a first cylindrical portion212. The first cylindrical portion212can be formed in a cylindrical shape in which both the front and the rear are opened. A first communication hole2122can be formed in an outer circumferential surface of the first cylindrical portion212. The front of the first cylindrical portion212can communicate with the first intake muffler161. A diameter of a front end of the first cylindrical portion212can be larger than the diameter of the rear end of the first intake muffler161. The first intake muffler161can be positioned inside the front end of the first cylindrical portion212. The first cylindrical portion212can be coupled to the back cover123.

In the first cylindrical portion212, a first flange214, a second flange216, a third coupling portion218, first ribs2126and2130, and a first communication hole2122, a second rib2128, a second communication hole2124, a partition wall2184, a protrusion2142, and third ribs2144and2148can be formed.

The second intake muffler210can include the first flange214. The first flange214can extend radially outward from the front of the first cylindrical portion212. The first flange214can radially overlap a front end of the muffler body220. The protrusion2142disposed adjacent to an internal flow path and protruding forward can be formed on a front surface of the first flange214. A radially protruding length of the first flange214can be greater than a radially protruding length of the second flange216.

The second intake muffler210can include the second flange216. The second flange216can extend radially outward from a central area of the first cylindrical portion212. The second flange216can be disposed between the first flange214and the third coupling portion218. The second flange216can contact a third flange224of the muffler body220. Specifically, a rear surface of the second flange216can contact a front surface of the third flange224of the muffler body220. An elastic member240can be disposed between the second flange216and the third flange224. The drawings illustrate that a third groove2244is formed only in the third flange224, by way of example. However, unlike this, a groove in which the elastic member240is disposed can also be formed in the second flange216.

The second intake muffler210can include the third coupling portion218. The third coupling portion218can be formed at the rear of the second intake muffler210. The third coupling portion218can protrude radially outward from the rear end of the first cylindrical portion212. The third coupling portion218can be formed in a shape corresponding to the opening1230of the back cover123. The third coupling portion218can pass through the opening1230of the back cover123, rotate, and be seated on the rear surface of the back cover123. In this case, the third coupling portion218and the opening1230of the back cover123can be formed in an oval or polygonal shape.

Through this, it is possible to firmly couple the back cover123made of a metal material and the second muffler unit200made of a non-metal material. In addition, the second intake muffler210can be coupled to the opening1230of the back cover123without a separate welding process.

The second intake muffler210can include the first communication hole2122formed in its outer circumferential surface. The first communication hole2122can be formed in the first cylindrical portion212. The first communication hole2122can be formed between the first flange214and the second flange216. The first communication hole2122can communicate an inside of the second intake muffler210with a space between the second intake muffler210and the muffler body220. The space between the second intake muffler210and the muffler body220in which the first communication hole2122is formed can be referred to as a “first expansion space.” The first communication hole2122can include a plurality of first communication holes2122that are spaced apart in a circumferential direction. Through this, the present disclosure can improve noise filtering characteristics through an additional expansion room of the second muffler unit200.

In some implementations, the first communication hole2122is described as having a rectangular shape by way of example, but the shape of the first communication hole2122can be variously changed.

The space between the second intake muffler210and the muffler body220may not axially overlap the first intake muffler161. Only a part of the space between the second intake muffler210and the muffler body220can axially overlap the piston150. Through this, the present disclosure can improve space efficiency while improving noise filtering characteristics of the muffler units160and200.

The second intake muffler210can include the second communication hole2124formed in its outer circumferential surface. The second communication hole2124can be formed in the first cylindrical portion212. The second communication hole2124can be formed between the second flange216and the third coupling portion218. The second communication hole2124can communicate the inside of the second intake muffler210with a space between the second intake muffler210, the muffler body220, the muffler cover230, and the back cover123. The space between the second intake muffler210, the muffler body220, the muffler cover230, and the back cover123can be referred to as a “second expansion space.” The second communication hole2124can include a plurality of second communication holes2124that are spaced apart in a circumferential direction. Through this, the present disclosure can improve noise filtering characteristics through an additional expansion room of the second muffler unit200.

In some implementations, the second communication hole2124is described as having a rectangular shape by way of example, but the shape of the second communication hole2124can be variously changed.

A diameter of the space between the second intake muffler210, the muffler body220, the muffler cover230, and the back cover123can be greater than a diameter of the space between the second intake muffler210and the muffler body220. Through this, the present disclosure can improve noise reduction efficiency of the second muffler unit.

The second intake muffler210can include the partition wall2184. The partition wall2184can partition an inner space2182of the first cylindrical portion212. The partition wall2184can be formed only in a rear area of the first cylindrical portion212. The partition wall2184can radially overlap the second communication hole2124. The partition wall2184can radially overlap the space between the second intake muffler210, the muffler body220, the muffler cover230, and the back cover123. Through this, the present disclosure can improve the space efficiency while improving the intake efficiency of the refrigerant.

The second intake muffler210can include the first ribs2126and2130. The first ribs2126and2130can protrude radially outward from the outer circumferential surface of the second intake muffler210. The first ribs2126and2130can protrude radially outward from the outer circumferential surface of the first cylindrical portion212. The first ribs2126and2130can extend in the circumferential direction. A part of the first ribs2126and2130can be disposed between the first flange214and the second flange216, and other part can be disposed between the second flange216and the third coupling portion218.

A part of the first ribs2126and2130can overlap the first communication hole2122in the circumferential direction. Through this, the present disclosure can improve the rigidity of the second intake muffler210without affecting the flow of the refrigerant flowing inside the second intake muffler210.

The first ribs2126and2130can include a plurality of first ribs2126and2130that are axially spaced apart from each other. In some implementations, the plurality of first ribs2126and2130can be configured such that the three first ribs are disposed between the first flange214and the second flange216, and the two first ribs are disposed between the second flange216and the third coupling portion218, by way of example. However, the present disclosure is not limited thereto, and the number of first ribs2126and2130can be variously changed.

The second intake muffler210can include the second rib2128. The second rib2128can extend axially between the first flange214and the second flange216. The second rib2128can include a first area2128bextending axially from the outer circumferential surface of the first cylindrical portion212; a second area2128athat is connected to the first area2128b, protrudes rearward from the rear surface of the first flange214, and extends radially; and a third area2128cthat is connected to the first area2128b, protrudes forward from the front surface of the second flange216, and extends radially.

The second rib2128can overlap a part (e.g.,2126) of the first ribs2126and2130. A radially protruding length of the second rib2128can be greater than radially protruding lengths of the first ribs2126and2130.

Through this, the present disclosure can prepare for vibration applied to the second intake muffler210by improving the rigidity of the second intake muffler210in a plurality of directions.

The second intake muffler210can include the third ribs2144and2148. The third ribs2144and2148can be formed on the first flange214. The third ribs2144and2148can protrude forward from the front surface of the first flange214. The third ribs2144and2148can protrude radially. Through this, the rigidity of the first flange214can be improved.

The third ribs2144and2148can include a plurality of third ribs2144and2148spaced apart in the circumferential direction. The plurality of third ribs2144and2148can be radially disposed based on a central area of the first flange214. A part (e.g.,2144) of the plurality of third ribs2144and2148can be formed in a different shape from a shape of other part (e.g.,2148). Through this, the coupling direction of the second intake muffler210including the first flange214can be guided.

The third ribs2144and2148may not axially overlap the second rib2128. Through this, the present disclosure can improve the space efficiency while improving the rigidity of the second intake muffler210.

An area where the third ribs2144and2148and the protrusion2142are connected can be formed as a curved surface2146.

The muffler body220can surround the second intake muffler210. When the second intake muffler210is coupled to the opening1230, the muffler body220can be press-fitted to the back cover123. The muffler body220can include a second cylindrical portion222and the third flange224.

The second cylindrical portion222can be disposed at a radially outside of the second intake muffler210. The second cylindrical portion222can be formed in a cylindrical shape with an opened rear. Specifically, the second cylindrical portion222can have a shape in which a front and a rear of a central area are opened, a front of a space between an inner surface222band an outer surface222cis closed, and a rear of the space between the inner surface222band the outer surface222cis opened.

The third flange224can extend inward from the inner surface222bof the second cylindrical portion222. An inner area of the third flange224can axially overlap an outer area of the second flange216. The third flange224can contact the second flange216. Specifically, the front surface of the third flange224can contact the rear surface of the second flange216. Through this, when the third coupling portion218of the second intake muffler210is coupled to the opening1230of the back cover123, the muffler body220can be press-fitted between the second intake muffler210and the back cover123.

The elastic member240can be disposed between the third flange224and the second flange216. The third flange224can include the third groove2244in which the elastic member240is seated. The present disclosure describes that the third groove2244is formed only in the third flange224, by way of example, but the third groove2244can be formed in at least one of the front surface of the third flange224and the rear surface of the second flange216. The third groove2244can extend in the circumferential direction. Through this, the present disclosure can guide a position of the elastic member240disposed between the second intake muffler210and the muffler body220, and can improve the coupling stability by allowing the second muffler unit200to be press-fitted to the back cover123while removing a gap between the second intake muffler210and the muffler body220.

A hole2242can be formed in the central area of the third flange224. The first cylindrical portion212of the second intake muffler210can be disposed in the hole2242.

The muffler body220can include a resonance communication hole2228. The resonance communication hole2228can be formed in the inner surface222bof the second cylindrical portion222. The resonance communication hole2228can communicate a space between the second intake muffler210and the second cylindrical portion222with a space between the muffler body220and the muffler cover230. The resonance communication hole2228can communicate a space between the second intake muffler210and the second cylindrical portion222with a space between the second cylindrical portion222and a ring portion234.

The resonance communication hole2228can be disposed adjacent to the third flange224. Through this, noise generated in the piston150can be easily introduced into the resonator via the resonance communication hole2228.

The space between the second cylindrical portion222and the ring portion234can be understood as a space between the inner surface222b, the outer surface222c, and a front surface222aof the second cylindrical portion222and the ring portion234. The space between the second cylindrical portion222and the ring portion234can be referred to as a “resonator.”

The resonator that is the space between the inner surface222b, the outer surface222c, and the front surface222aof the second cylindrical portion222and the ring portion234can form a closed space by the second cylindrical portion222and the ring portion234except for the resonance communication hole2228.

An axial length of the space between the muffler body220and the muffler cover230can be greater than a radial length of the space between the muffler body220and the muffler cover230. The space between the muffler body220and the muffler cover230may not axially overlap the piston150.

Due to the additional resonator, it is possible to reduce noise of a low frequency or mid-frequency in the 1.25 kHz frequency band.

The muffler body220can include a fourth rib2224. The fourth rib2224can protrude radially outward from the outer surface222cor the outer circumferential surface of the second cylindrical portion222. The fourth rib2224can extend axially. Through this, the rigidity of the muffler body220can be improved.

The fourth rib2224can contact a leg portion1234of the back cover123. The back cover123can include a support member1232in which the opening1230is formed, a plurality of leg portions1234that extend forward from a radially outside of the support member1232and are spaced apart in the circumferential direction, and a plurality of extension members1236that extend radially from the support member1232and are spaced apart in the circumferential direction. The fourth rib2224can include a plurality of fourth ribs2224spaced apart in the circumferential direction. Each of the plurality of fourth ribs2224can contact each of the plurality of leg portions1234. Through this, the present disclosure can guide the position of the muffler body220relative to the back cover123and press-fit the muffler body220to the back cover123.

The muffler body220can include a fifth rib2248. The fifth rib2248can be formed in an area between the inner surface222bof the second cylindrical portion222and the front surface of the third flange224. Specifically, the fifth rib2248can extend from the inner surface222bof the second cylindrical portion222to the front surface of the third flange224. Through this, the rigidity of the area connecting the second cylindrical portion222and the third flange224can be improved.

The fifth rib2248can be closer to the inner surface222bof the second cylindrical portion222as the fifth rib2248becomes distant from the front surface of the third flange224. Specifically, as the fifth rib2248becomes distant from the front surface of the third flange224, a length of the fifth rib2248from the inner surface222bof the second cylindrical portion222can decrease. Through this, the position of the second flange216relative to the third flange224can be guided.

The muffler body220can include a plurality of first grooves2222. The plurality of first grooves2222can be concave inward from the outer surface222cof the second cylindrical portion222. The plurality of first grooves2222can be concavely formed rearward from the front surface222aof the second cylindrical portion222. The plurality of first grooves2222can be spaced apart from each other in the circumferential direction. In some implementations three first grooves2222may be defined, by way of example, but other implementations are not limited thereto. For example, the number of first grooves2222can be variously changed.

The first groove2222can include a base surface2222a, a first stepped portion2222bthat connects the base surface2222aand the outer surface222cof the second cylindrical portion222and extends in the circumferential direction, and second and third stepped portions2222cthat connect the base surface2222aand the outer surface222cof the second cylindrical portion222and extend axially.

The plurality of first grooves2222can axially overlap the support portion119cof the spring supporter119. Through this, the present disclosure can prevent interference between the muffler body220and the spring supporter119and improve the space efficiency.

A resonator can be formed between the plurality of first grooves2222in the circumferential direction. Specifically, a space between the muffler body220and the muffler cover230can be formed between the plurality of first grooves2222in the circumferential direction. More specifically, the space between the inner surface222b, the outer surface222c, and the front surface222aof the second cylindrical portion222and the ring portion234can be formed each between the plurality of first grooves2222in the circumferential direction. The plurality of resonance communication holes2228can be disposed between the plurality of first grooves2222in the circumferential direction. Through this, it is possible to improve space efficiency while preventing interference with other configurations.

The muffler body220can include sixth ribs2236and2238. The sixth ribs2236and2238can extend rearward from a rear surface of the first stepped portion2222bof the first groove2222. Through this, the rigidity of the plurality of first grooves2222can be improved.

The sixth ribs2236and2238can include an inner rib2236formed at the inside and an outer rib2238disposed at a radially outside of the inner rib2236. An axial length of the outer rib2238can be greater than an axial length of the inner rib2236. Specifically, a protruding length of the outer rib2238from the first stepped portion2222bcan be greater than a protruding length of the inner rib2236. Through this, the position of the muffler cover230relative to the muffler body220can be guided.

The muffler cover230can be seated on the sixth ribs2236and2238. The ring portion234can be seated on the outer rib2238, and a second extension232can be seated on the inner rib2236.

The muffler body220can include a guide groove2226. The guide groove2226can be formed in the front surface222aof the second cylindrical portion222. The guide groove2226can include a plurality of guide grooves2226spaced apart in the circumferential direction. The guide groove2226can radially overlap the fourth rib2224. Through this, when the second muffler unit200is coupled to the back cover123, a correct coupling direction can be guided to a user.

An area2234which is opened rearward between the inner surface222band the outer surface222cin the muffler body220can be referred to as a “resonator.” The area2234which is opened rearward between the inner surface222band the outer surface222cin the muffler body220can be sealed by the muffler cover230. That is, this can be understood as the same meaning as the space between the muffler body220and the muffler cover230.

The muffler body220can include an eighth rib2235. The eighth rib2235can be formed in the area2234which is opened rearward between the inner surface222band the outer surface222cin the muffler body220. The eighth rib2235can be formed in a space between the plurality of first grooves2222. Specifically, the eighth rib2235can be formed in a space between the second and third stepped portions2222c. The eighth rib2235can protrude inward from the outer surface222cof the muffler body220. Through this, it is possible to improve the rigidity of the resonator of the muffler body220while improving the space efficiency.

The muffler cover230can be disposed between the muffler body220and the back cover123. The muffler cover230can be seated on the sixth ribs2236and2238. When the second intake muffler210is coupled to the opening1230, the muffler cover230can be press-fitted to the back cover123. The muffler cover230can be entirely formed in a ring shape or a circular band shape.

The muffler cover230can include the ring portion234, a first extension236, and the second extension232. The central area of the ring portion234can be opened. The ring portion234can extend in the circumferential direction. The ring portion234can be formed in a ring shape or a circular band shape. The first extension236can extend rearward from the outer surface or the outer end of the ring portion234. The second extension232can extend forward from the inner surface or the inner end of the ring portion234.

The ring portion234and the second extension232can contact the muffler body220. The second extension232can be seated on the inner rib2236. The ring portion234can be seated on the outer rib2238. The first extension236can contact the back cover123. An outer surface of the first extension236and an inner surface of the second extension232can contact the second cylindrical portion222. Through this, when the third coupling portion218of the second intake muffler210is coupled to the opening1230of the back cover123, the muffler cover230can be press-fitted between the muffler body220and the back cover123.

The ring portion234can seal a rear opened between the inner surface222band the outer surface222cof the second cylindrical portion222. The outer surface of the first extension236can contact the second cylindrical portion222.

The muffler cover230can include a seventh rib238. The seventh rib238can be formed between the rear surface of the ring portion234and the inner surface of the first extension236. The seventh rib238can include a plurality of seventh rib units2382and2384spaced apart in the circumferential direction. The plurality of seventh rib units2382and2384can face each other. The support bracket123acan be disposed between the plurality of seventh rib units2382and2384. Through this, the present disclosure can guide the position of the muffler cover230and improve the rigidity of the muffler cover230.

The muffler cover230can include a fourth coupling portion2364. The fourth coupling portion2364can protrude radially outward from the first extension236. A straight line extending the fourth coupling portion2364can be disposed between the plurality of seventh rib units2382and2384. The fourth coupling portion2364can be seated in a second groove2230concavely formed from the inside to the outside of the fourth rib2224. The fourth coupling portion2364can include a plurality of fourth coupling portions2364spaced apart in the circumferential direction. Through this, the present disclosure can guide the position of the muffler cover230relative to the muffler body220while improving the rigidity of the muffler cover230and the muffler body220.

FIG.24is a block diagram of multiple resonators. A space between the inner guide162and the piston150can be described as a first resonator HR1, and an additional resonator that is the space between the second cylindrical portion222and the ring portion234can be described as a second resonator HR2.

Referring toFIG.25, when only the first resonator HR1 is present, only the transmission loss in the 100 Hz band is improved, and when only the second resonator HR2 is present, only the transmission loss in the 250 Hz band is improved. Compared to this, when the first resonator HR1 and the second resonator HR2 are linearly arranged, the transmission loss in both the 100 Hz and 250 Hz bands can be improved, and the transmission loss in a frequency band (e.g., 200 Hz) between the respective resonators HR1 and HR2 can also be improved.

When the resonators HR1 and HR2 are applied to the linear compressor100, the first resonator HR1 can improve the transmission loss in the 800 Hz band, the second resonator HR2 can improve the transmission loss in the 1.25 kHz band, and the resonators HR1 and HR2 can improve the transmission loss in the 800 Hz and 1.25 kHz bands.

Referring toFIG.26, noise reduction characteristics of the muffler units160and200of the linear compressor100can be further improved compared to the related art. Specifically, noise in a low or mid-frequency band between 800 Hz and 1.2 kHz can be reduced, and noise in a high-frequency band between 2 kHz and 2.5 kHz can also be reduced. The insertion loss (IL) can be understood as expressing a difference in a sound level before and after mounting the muffler units160and200on a dB scale.

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

For example, configuration “A” described in an implementation and/or the drawings and configuration “B” described in another implementation 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.