Patent Publication Number: US-2023145653-A1

Title: Compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage filing under 35 U.S.C. 371 of International 
     Application No. PCT/KR2020/004388, filed on Mar. 31, 2020, which claims the benefit of Korean Patent Application No. 10-2020-0006189, filed on Jan. 16, 2020, the contents of which are all hereby incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a compressor. More specifically, the present disclosure relates to a linear compressor for compressing a refrigerant by a linear reciprocating motion of a piston. 
     BACKGROUND ART 
     In general, a compressor refers to a device that is configured to receive power from a power generator such as a motor or a turbine and compress a working fluid such as air or refrigerant. More specifically, the compressors are widely used in the whole industry or home appliances, such as for a steam compression refrigeration cycle (hereinafter, referred to as “refrigeration cycle”). 
     The compressors may be classified into a reciprocating compressor, a rotary compressor, and a scroll compressor according to a method of compressing the refrigerant. 
     The reciprocating compressor uses a method in which a compression space is formed between a piston and a cylinder, and the piston linearly reciprocates to compress a fluid. The rotary compressor uses a method of compressing a fluid by a roller that eccentrically rotates inside a cylinder. The scroll compressor uses a method of compressing a fluid by engaging and rotating a pair of spiral scrolls. 
     Recently, among the reciprocating compressors, the use of linear compressors that uses a linear reciprocating motion without using a crank shaft is gradually increasing. The linear compressor has advantages in that it has less mechanical loss resulting from switching a rotary motion to the linear reciprocating motion and thus can improve the efficiency, and has a relatively simple structure. 
     The linear compressor is configured such that a cylinder is positioned in a casing forming a sealed space to form a compression chamber, and a piston covering the compression chamber reciprocates in the cylinder. The linear compressor repeats a process in which a fluid in the sealed space is sucked into the compression chamber while the piston is positioned at a bottom dead center (BDC), and the fluid of the compression chamber is compressed and discharged while the piston is positioned at a top dead center (TDC). 
     A compression unit and a drive unit are installed inside the linear compressor. The compression unit performs a process of compressing and discharging a refrigerant while performing a resonant motion by a resonant spring through a movement generated in the drive unit. 
     The piston of the linear compressor repeatedly performs a series of processes of sucking the refrigerant into the casing through an intake pipe while reciprocating at high speed inside the cylinder by the resonant spring, and then discharging the refrigerant from a compression space through a forward movement of the piston to move it to a condenser through a discharge pipe. 
     The linear compressor may be classified into an oil lubricated linear compressor and a gas lubricated linear compressor according to a lubrication method. 
     The oil lubricated linear compressor is configured to store a predetermined amount of oil in the casing and lubricate between the cylinder and the piston using the oil. 
     On the other hand, the gas lubricated linear compressor is configured not to store an oil in the casing, induce a part of the refrigerant discharged from the compression space between the cylinder and the piston, and lubricate between the cylinder and the piston by a gas force of the refrigerant. 
     The oil lubricated linear compressor supplies the oil of a relatively low temperature between the cylinder and the piston and thus can suppress the cylinder and the piston from being overheated by motor heat or compression heat, etc. Hence, the oil lubricated linear compressor suppresses specific volume from increasing as the refrigerant passing through an intake flow path of the piston is sucked into the compression chamber of the cylinder and is heated, and thus can prevent in advance an intake loss from occurring. 
     However, when the refrigerant and an oil discharged to a refrigeration cycle device are not smoothly returned to the compressor, the oil lubricated linear compressor may experience an oil shortage in the casing of the compressor. The oil shortage in the casing may lead to a reduction in reliability of the compressor. 
     On the other hand, the gas lubricated linear compressor has advantages in that it can be made smaller than the oil lubricated linear compressor, and there is no reduction in the reliability of the compressor due to the oil shortage because it lubricates between the cylinder and the piston using the refrigerant. 
     However, there was a problem that damage to the product was caused since a lateral force was applied to the piston that reciprocates axially. 
     DISCLOSURE 
     Technical Problem 
     An object of the present disclosure is to provide a piston capable of distributing a lateral force applied to the piston and reducing manufacturing process of components. 
     Technical Solution 
     To achieve the above-described and other objects, in one aspect of the present disclosure, there is provided a compressor, the compressor comprising the cylinder configured to form a compressed space of the refrigerant, the cylinder having a cylindrical shape; a piston configured to reciprocate axially in the cylinder, the piston comprising a guide portion having a cylindrical shape and a head portion disposed in front of the guide portion; an intake valve disposed at a front of the head portion; a fixing member disposed outside the piston; a rod comprising one end disposed at the head portion and configured to extend axially; a first elastic member connected to the fixing member and other side of the rod; a second elastic member disposed to be spaced apart from a rear of the first elastic member and connected to the fixing member and the other side of the rod; and a first spacer insert-injected with the first elastic member and the second elastic member. 
     Hence, the present disclosure can distribute a lateral force applied to the piston through the rod that axially extends in the piston. 
     Further, since the first spacer is insert-injected with the first elastic member and the second elastic member, the present disclosure can improve rigidity of the product and reduce the manufacturing process of components. 
     The first elastic member comprises a first inner portion connected to the other side of the rod, a first outer portion connected to the fixing member, and a first connection portion connecting the first inner portion and the first outer portion. The second elastic member comprises a second inner portion axially overlapping the first inner portion, a second outer portion axially overlapping the first outer portion, and a second connection portion connecting the second inner portion and the second outer portion. 
     The first spacer may comprise an inner spacer insert-injected with the first inner portion and the second inner portion. The inner spacer may cover a front surface, an outer surface, and a rear surface of the first inner portion and a front surface, an outer surface, and a rear surface of the second inner portion. 
     The inner spacer may comprise a first hole formed in a central area, and the first inner portion may comprise a first inner hole that is formed in the central area and axially overlaps the first hole. The second inner portion may comprise a second inner hole that is formed in the central area and axially overlaps the first hole, and other end of the rod may axially overlap the first hole, the first inner hole, and the second inner hole. 
     The compressor may further comprise a coupling member coupled to the other end of the rod, and the coupling member may pass through the first hole, the first inner hole, and the second inner hole. 
     The compressor may further comprise a first fastening member configured to fix other end of the coupling member to a rear surface of the inner spacer. 
     A radius of the coupling member may be greater than a radius of a central area of the rod, and one side of the coupling member may be formed in a shape corresponding to the other end of the rod. 
     The first spacer may comprise an outer spacer insert-injected with the first outer portion and the second outer portion. The outer spacer may cover a front surface, an outer surface, and a rear surface of the first outer portion and a front surface, an outer surface, and a rear surface of the second outer portion. 
     The compressor may further comprise a second fastening member configured to couple the outer spacer, the first outer portion, and the second outer portion to the fixing member. 
     The outer spacer may comprise a second hole axially overlapping the fixing member, and the first outer portion may comprise a first outer hole axially overlapping the second hole. The second outer portion may comprise a second outer hole axially overlapping the second hole, and the fixing member comprises a fastening hole axially overlapping the second hole. The second fastening member may pass through the second hole, the first outer hole, the second outer hole, and the fastening hole. 
     The fixing member may comprise an extension that extends forward at a position axially overlapping the second hole. 
     The first connection portion may comprise a plurality of first connection members that is formed in a spiral shape and is spaced apart from each other, and the second connection portion may comprise a plurality of second connection members that is formed in a spiral shape and is spaced apart from each other. 
     A rear surface of the piston and the first elastic member may be axially spaced apart from each other. The refrigerant at a rear of the piston may be introduced into the piston via a space between the plurality of first connection members, a space between the plurality of second connection members, and a space between the rear surface of the piston and the first elastic member. 
     The compressor may further comprise a second spacer disposed between a rear surface of the first inner portion and a front surface of the second inner portion, and the first spacer may comprise an outer spacer insert-injected with the first outer portion and the second outer portion. 
     The head portion of the piston may comprise a rod groove formed in a central area, and the one end of the rod may be disposed in the rod groove. 
     The first elastic member and the second elastic member each may comprise a leaf spring. 
     To achieve the above-described and other objects, in another aspect of the present disclosure, there is provided a compressor comprising the cylinder configured to form a compressed space of the refrigerant, the cylinder having a cylindrical shape; a piston configured to reciprocate axially in the cylinder, the piston comprising a guide portion having a cylindrical shape and a head portion disposed in front of the guide portion; an intake valve disposed at a front of the head portion; a fixing member disposed outside the piston; a rod comprising one end disposed at the head portion and configured to extend axially; a first elastic member connected to the fixing member and other side of the rod; a second elastic member disposed to be spaced apart from a rear of the first elastic member and connected to the fixing member and the other side of the rod; and a spacer disposed between the first elastic member and the second elastic member. 
     Hence, the present disclosure can distribute a lateral force applied to the piston through the rod that axially extends in the piston. 
     The first elastic member may comprise a first inner portion connected to other end of the rod, a first outer portion connected to the fixing member, and a first connection portion connecting the first inner portion and the first outer portion. The second elastic member may comprise a second inner portion axially overlapping the first inner portion, a second outer portion axially overlapping the first outer portion, and a second connection portion connecting the second inner portion and the second outer portion. 
     The first inner portion may comprise a first inner hole formed in the central area, and the second inner portion may comprise a second inner hole that is formed in the central area and axially overlaps the first inner hole. The other end of the rod may axially overlap the first inner hole and the second inner hole, and the spacer may be disposed between the first inner portion and the second inner portion and disposed adjacent to the first inner hole or the second inner hole. 
     The first outer portion may comprise a first outer hole, and the second outer portion may comprise a second outer hole axially overlapping the first outer hole. The spacer may be disposed between the first outer portion and the second outer portion and disposed adjacent to the first outer hole or the second outer hole. 
     Advantageous Effects 
     The present disclosure can provide a piston capable of distributing a lateral force applied to the piston and reducing the manufacturing process of components. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view of a compressor according to an embodiment of the present disclosure. 
         FIG.  2    is a cross-sectional view of a compressor according to an embodiment of the present disclosure. 
         FIGS.  3  and  4    are perspective views of partial configuration of a compressor according to an embodiment of the present disclosure. 
         FIG.  5    is an exploded perspective view of partial configuration of a compressor according to an embodiment of the present disclosure. 
         FIG.  6    is an exploded perspective view of partial configuration of  FIG.  5   . 
         FIG.  7    is a side view of partial configuration of a compressor according to an embodiment of the present disclosure. 
         FIG.  8    is a cross-sectional view of partial configuration of a compressor according to an embodiment of the present disclosure. 
         FIG.  9    is a plan view of an elastic member according to an embodiment of the present disclosure. 
         FIGS.  10  and  11    are perspective views of an elastic member and a spacer according to another embodiment of the present disclosure. 
         FIGS.  12  and  13    are perspective views of an elastic member and a spacer according to yet another embodiment of the present disclosure. 
         FIG.  14    is a perspective view of an elastic member and a spacer according to still yet another embodiment of the present disclosure. 
     
    
    
     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 can 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.  1    is a perspective view of a compressor according to an embodiment of the present disclosure. 
     Referring to  FIG.  1   , a linear compressor  100  according to an embodiment of the present disclosure may include a shell  111  and shell covers  112  and  113  coupled to the shell  111 . In a broad sense, the shell covers  112  and  113  can be understood as one configuration of the shell  111 . 
     Legs  20  may be coupled to a lower side of the shell  111 . The legs  20  may be coupled to a base of a product on which the linear compressor  100  is 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 shell  111  may have a substantially cylindrical shape and may be disposed to lie in a horizontal direction or an axial direction.  FIG.  1    illustrates that the shell  111  is extended in the horizontal direction and has a slightly low height in a radial direction, by way of example. That is, since the linear compressor  100  can have a low height, there is an advantage in that a height of the machine room can decrease when the linear compressor  100  is installed in, for example, the machine room base of the refrigerator. 
     A longitudinal central axis of the shell  111  coincides with a central axis of a main body of the compressor  100  to be described below, and the central axis of the main body of the compressor  100  coincides with a central axis of a cylinder  140  and a piston  150  that constitute the main body of the compressor  100 . 
     A terminal  30  may be installed on an outer surface of the shell  111 . The terminal  30  may transmit external electric power to a drive unit  130  of the linear compressor  100 . More specifically, the terminal  30  may be connected to a lead line of a coil  132   b.    
     A bracket  31  may be installed on the outside of the terminal  30 . The bracket  31  may include a plurality of brackets surrounding the terminal  30 . The bracket  31  may perform a function of protecting the terminal  30  from an external impact, etc. 
     Both sides of the shell  111  may be opened. The shell covers  112  and  113  may be coupled to both sides of the opened shell  111 . More specifically, the shell covers  112  and  113  may include a first shell cover  112  coupled to one opened side of the shell  111  and a second shell cover  113  coupled to the other opened side of the shell  111 . An inner space of the shell  111  may be sealed by the shell covers  112  and  113 . 
       FIG.  1    illustrates that the first shell cover  112  is positioned on the right side of the linear compressor  100 , and the second shell cover  113  is positioned on the left side of the linear compressor  100 , by way of example. In other words, the first and second shell covers  112  and  113  may be disposed to face each other. It can be understood that the first shell cover  112  is positioned on an intake side of a refrigerant, and the second shell cover  113  is positioned on a discharge side of the refrigerant. 
     The linear compressor  100  may include a plurality of pipes  114 ,  115 , and  40  that are included in the shell  111  or the shell covers  112  and  113  and can suck, discharge, or inject the refrigerant. 
     The plurality of pipes  114 ,  115 , and  40  may include an intake pipe  114  that allows the refrigerant to be sucked into the linear compressor  100 , a discharge pipe  115  that allows the compressed refrigerant to be discharged from the linear compressor  100 , and a supplementary pipe  40  for supplementing the refrigerant in the linear compressor  100 . 
     For example, the intake pipe  114  may be coupled to the first shell cover  112 . The refrigerant may be sucked into the linear compressor  100  along the axial direction through the intake pipe  114 . 
     The discharge pipe  115  may be coupled to an outer circumferential surface of the shell  111 . The refrigerant sucked through the intake pipe  114  may be compressed while flowing in the axial direction. The compressed refrigerant may be discharged through the discharge pipe  115 . The discharge pipe  115  may be disposed closer to the second shell cover  113  than to the first shell cover  112 . 
     The supplementary pipe  40  may be coupled to the outer circumferential surface of the shell  111 . A worker may inject the refrigerant into the linear compressor  100  through the supplementary pipe  40 . 
     The supplementary pipe  40  may be coupled to the shell  111  at a different height from the discharge pipe  115  in order to prevent interference with the discharge pipe  115 . Herein, the height may be understood as a distance measured from the leg  20  in a vertical direction. Because the discharge pipe  115  and the supplementary pipe  40  are coupled to the outer circumferential surface of the shell  111  at different heights, the work convenience can be attained. 
     On an inner circumferential surface of the shell  111  corresponding to a location at which the supplementary pipe  40  is coupled, at least a portion of the second shell cover  113  may be positioned adjacently. In other words, at least a portion of the second shell cover  113  may act as a resistance of the refrigerant injected through the supplementary pipe  40 . 
     Thus, with respect to a flow path of the refrigerant, a size of the flow path of the refrigerant introduced through the supplementary pipe  40  is configured to decrease by the second shell cover  113  while the refrigerant enters into the inner space of the shell  111 , and to increase again while the refrigerant passes through the second shell cover  113 . 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 piston  150 , a compression performance of the refrigerant can be improved. The oil may be understood as a working oil present in a cooling system. 
       FIG.  2    is a cross-sectional view illustrating a structure of the compressor  100 . 
     Hereinafter, the compressor  100  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 compressor may be a component of a refrigeration cycle, and the fluid compressed in the linear compressor may be a refrigerant circulating the refrigeration cycle. The refrigeration cycle may include a condenser, an expander, an evaporator, etc., in addition to the compressor. The linear compressor may be used as a component of the cooling system of the refrigerator, but is not limited thereto. The linear compressor can be widely used in the whole industry. 
     Referring to  FIG.  2   , the compressor  100  may include a casing  110  and a main body received in the casing  110 . The main body of the compressor  100  may include a frame  120 , the cylinder  140  fixed to the frame  120 , the piston  150  that linearly reciprocates inside the cylinder  140 , the drive unit  130  that is fixed to the frame  120  and gives a driving force to the piston  150 , and the like. Here, the cylinder  140  and the piston  150  may be referred to as compression units  140  and  150 . 
     The compressor  100  may include a bearing means for reducing a friction between the cylinder  140  and the piston  150 . 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 compressor  100  may be elastically supported by support springs  116  and  117  installed at both ends in the casing  110 . The support springs  116  and  117  may include a first support spring  116  for supporting the rear of the main body and a second support spring  117  for supporting a front of the main body. The support springs  116  and  117  may include a leaf spring. The support springs  116  and  117  can absorb vibrations and impacts generated by a reciprocating motion of the piston  150  while supporting the internal parts of the main body of the compressor  100 . 
     The casing  110  may define a sealed space. The sealed space may include an accommodation space  101  in which the sucked refrigerant is received, an intake space  102  which is filled with the refrigerant before the compression, a compression space  103  in which the refrigerant is compressed, and a discharge space  104  which is filled with the compressed refrigerant. 
     The refrigerant sucked from the intake pipe  114  connected to the rear side of the casing  110  may be filled in the accommodation space  101 , and the refrigerant in the intake space  102  communicating with the accommodation space  101  may be compressed in the compression space  103 , discharged into the discharge space  104 , and discharged to the outside through the discharge pipe  115  connected to the front side of the casing  110 . 
     The casing  110  may include the shell  111  formed in a substantially cylindrical shape that is open at both ends and is long in a transverse direction, the first shell cover  112  coupled to the rear side of the shell  111 , and the second shell cover  113  coupled to the front side of the shell  111 . 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 cover  112  and the second shell cover  113  may be formed as one body with the shell  11 . 
     The casing  110  may be formed of a thermally conductive material. Hence, heat generated in the inner space of the casing  110  can be quickly dissipated to the outside. 
     The first shell cover  112  may be coupled to the shell  111  in order to seal the rear of the shell  111 , and the intake pipe  114  may be inserted and coupled to the center of the first shell cover  112 . 
     The rear of the main body of the compressor  100  may be elastically supported by the first support spring  116  in the radial direction of the first shell cover  112 . 
     The first support spring  116  may include a circular leaf spring. An edge of the first support spring  116  may be elastically supported by a support bracket  123   a  in a forward direction with respect to a back cover  123 . An opened center portion of the first support spring  116  may be supported by an intake guide  116   a  in a rearward direction with respect to the first shell cover  112 . 
     The intake guide  116   a  may have a through passage formed therein. The intake guide  116   a  may be formed in a cylindrical shape. A front outer circumferential surface of the intake guide  116   a  may be coupled to a central opening of the first support spring  116 , and a rear end of the intake guide  116   a  may be supported by the first shell cover  112 . In this instance, a separate intake support member  116   b  may be interposed between the intake guide  116   a  and an inner surface of the first shell cover  112 . 
     A rear side of the intake guide  116   a  may communicate with the intake pipe  114 , and the refrigerant sucked through the intake pipe  114  may pass through the intake guide  116   a  and may be smoothly introduced into a muffler unit  160  to be described below. 
     A damping member  116   c  may be disposed between the intake guide  116   a  and the intake support member  116   b.  The damping member  116   c  may 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 pipe  114  can be prevented from being transmitted to the first shell cover  112 . 
     The second shell cover  113  may be coupled to the shell  111  to seal the front side of the shell  111 , and the discharge pipe  115  may be inserted and coupled through a loop pipe  115   a . The refrigerant discharged from the compression space  103  may pass through a discharge cover assembly  180  and then may be discharged into the refrigeration cycle through the loop pipe  115   a  and the discharge pipe  115 . 
     A front side of the main body of the compressor  100  may be elastically supported by the second support spring  117  in the radial direction of the shell  111  or the second shell cover  113 . 
     The second support spring  117  may include a circular leaf spring. An opened center portion of the second support spring  117  may be supported by a first support guide  117   b  in a rearward direction with respect to the discharge cover assembly  180 . An edge of the second support spring  117  may be supported by a support bracket  117   a  in a forward direction with respect to the inner surface of the shell  111  or the inner circumferential surface of the shell  111  adjacent to the second shell cover  113 . 
     Unlike  FIG.  2   , the edge of the second support spring  117  may be supported in the forward direction with respect to the inner surface of the shell  111  or the inner circumferential surface of the shell  111  adjacent to the second shell cover  113  through a separate bracket (not shown) coupled to the second shell cover  113 . 
     The first support guide  117   b  may be formed in a cylindrical shape. A cross section of the first support guide  117   b  may have a plurality of diameters. A front side of the first support guide  117   b  may be inserted into a central opening of the second support spring  117 , and a rear side of the first support guide  117   b  may be inserted into a central opening of the discharge cover assembly  180 . A support cover  117   c  may be coupled to the front side of the first support guide  117   b  with the second support spring  117  interposed therebetween. A cup-shaped second support guide  117   d  that is recessed rearward may be coupled to the front side of the support cover  117   c.  A cup-shaped third support guide  117   e  that corresponds to the second support guide  117   d  and is recessed forward may be coupled to the inside of the second shell cover  113 . The second support guide  117   d  may be inserted into the third support guide  117   e  and may be supported in the axial direction and/or the radial direction. In this instance, a gap may be formed between the second support guide  117   d  and the third support guide  117   e.    
     The frame  120  may include a body portion  121  supporting the outer circumferential surface of the cylinder  140 , and a first flange portion  122  that is connected to one side of the body portion  121  and supports the drive unit  130 . The frame  120  may be elastically supported with respect to the casing  110  by the first and second support springs  116  and  117  together with the drive unit  130  and the cylinder  140 . 
     The body portion  121  may wrap the outer circumferential surface of the cylinder  140 . The body portion  121  may be formed in a cylindrical shape. The first flange portion  122  may extend from a front end of the body portion  121  in the radial direction. 
     The cylinder  140  may be coupled to an inner circumferential surface of the body portion  121 . An inner stator  134  may be coupled to an outer circumferential surface of the body portion  121 . For example, the cylinder  140  may be pressed and fitted to the inner circumferential surface of the body portion  121 , and the inner stator  134  may be fixed using a separate fixing ring (not shown). 
     An outer stator  131  may be coupled to a rear surface of the first flange portion  122 , and the discharge cover assembly  180  may be coupled to a front surface of the first flange portion  122 . For example, the outer stator  131  and the discharge cover assembly  180  may be fixed through a mechanical coupling means. 
     On one side of the front surface of the first flange portion  122 , a bearing inlet groove  125   a  forming a part of the gas bearing may be formed, a bearing communication hole  125   b  penetrating from the bearing inlet groove  125   a  to the inner circumferential surface of the body portion  121  may be formed, and a gas groove  125   c  communicating with the bearing communication hole  125   b  may be formed on the inner circumferential surface of the body portion  121 . 
     The bearing inlet groove  125   a  may be recessed to a predetermined depth along the axial direction. The bearing communication hole  125   b  is a hole having a smaller cross-sectional area than the bearing inlet groove  125   a  and may be inclined toward the inner circumferential surface of the body portion  121 . The gas groove  125   c  may be formed in an annular shape having a predetermined depth and an axial length on the inner circumferential surface of the body portion  121 . Alternatively, the gas groove  125   c  may be formed on the outer circumferential surface of the cylinder  140  in contact with the inner circumferential surface of the body portion  121 , or formed on both the inner circumferential surface of the body portion  121  and the outer circumferential surface of the cylinder  140 . 
     In addition, a gas inlet  142  corresponding to the gas groove  125   c  may be formed on the outer circumferential surface of the cylinder  140 . The gas inlet  142  forms a kind of nozzle in the gas bearing. 
     The frame  120  and the cylinder  140  may be formed of aluminum or an aluminum alloy material. 
     The cylinder  140  may be formed in a cylindrical shape in which both ends are opened. The piston  150  may be inserted through a rear end of the cylinder  140 . A front end of the cylinder  140  may be closed via a discharge valve assembly  170 . The compression space  103  may be formed between the cylinder  140 , a front end of the piston  150 , and the discharge valve assembly  170 . Here, the front end of the piston  150  may be referred to as a head portion  151 . The volume of the compression space  103  increases when the piston  150  moves backward, and decreases as the piston  150  moves forward. That is, the refrigerant introduced into the compression space  103  may be compressed while the piston  150  moves forward, and may be discharged through the discharge valve assembly  170 . 
     The cylinder  140  may include a second flange portion  141  disposed at the front end. The second flange portion  141  may bend to the outside of the cylinder  140 . The second flange portion  141  may extend in an outer circumferential direction of the cylinder  140 . The second flange portion  141  of the cylinder  140  may be coupled to the frame  120 . For example, the front end of the frame  120  may include a flange groove corresponding to the second flange portion  141  of the cylinder  140 , and the second flange portion  141  of the cylinder  140  may 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 the outer circumferential surface of the piston  150  and the outer circumferential surface of the cylinder  140  and lubricate between the cylinder  140  and the piston  150  with gas. The discharge gas between the cylinder  140  and the piston  150  may provide a levitation force to the piston  150  to reduce a friction generated between the piston  150  and the cylinder  140 . 
     For example, the cylinder  140  may include the gas inlet  142 . The gas inlet  142  may communicate with the gas groove  125   c  formed on the inner circumferential surface of the body portion  121 . The gas inlet  142  may pass through the cylinder  140  in the radial direction. The gas inlet  142  may guide the compressed refrigerant introduced in the gas groove  125   c  between the inner circumferential surface of the cylinder  140  and the outer circumferential surface of the piston  150 . Alternatively, the gas groove  125   c  may be formed on the outer circumferential surface of the cylinder  140  in consideration of the convenience of processing. 
     An entrance of the gas inlet  142  may be formed relatively widely, and an exit of the gas inlet  142  may be formed as a fine through hole to serve as a nozzle. The entrance of the gas inlet  142  may 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 inlets  142  may be independently formed. Alternatively, the entrance of the gas inlet  142  may be formed as an annular groove, and a plurality of exits may be formed along the annular groove at regular intervals. The gas inlet  142  may be formed only at the front side based on the axial direction center of the cylinder  140 . On the contrary, the gas inlet  142  may be formed at the rear side based on the axial direction center of the cylinder  140  in consideration of the sagging of the piston  150 . 
     The piston  150  is inserted into the opened rear end of the cylinder  140  and is provided to seal the rear of the compression space  103 . 
     The piston  150  may include a head portion  151  and a guide portion  152 . The head portion  151  may be formed in a disc shape. The head portion  151  may be partially open. The head portion  151  may partition the compression space  103 . The guide portion  152  may extend rearward from an outer circumferential surface of the head portion  151 . The guide portion  152  may be formed in a cylindrical shape. The inside of the guide portion  152  may be empty, and a front of the guide portion  152  may be partially sealed by the head portion  151 . A rear of the guide portion  152  may be opened and connected to the muffler unit  160 . The head portion  151  may be provided as a separate member coupled to the guide portion  152 . Alternatively, the head portion  151  and the guide portion  152  may be formed as one body. 
     The piston  150  may include an intake port  154 . The intake port  154  may pass through the head portion  151 . The intake port  154  may communicate with the intake space  102  and the compression space  103  inside the piston  150 . For example, the refrigerant flowing from the accommodation space  101  to the intake space  102  in the piston  150  may pass through the intake port  154  and may be sucked into the compression space  103  between the piston  150  and the cylinder  140 . 
     The intake port  154  may extend in the axial direction of the piston  150 . The intake port  154  may be inclined in the axial direction of the piston  150 . For example, the intake port  154  may extend to be inclined in a direction away from the central axis as it goes to the rear of the piston  150 . 
     A cross section of the intake port  154  may be formed in a circular shape. The intake port  154  may have a constant inner diameter. In contrast, the intake port  154  may be formed as a long hole in which an opening extends in the radial direction of the head portion  151 , or may be formed such that the inner diameter becomes larger as it goes to the rear. 
     The plurality of intake ports  154  may be formed in at least one of the radial direction and the circumferential direction of the head portion  151 . 
     The head portion  151  of the piston  150  adjacent to the compression space  103  may be equipped with an intake valve  155  for selectively opening and closing the intake port  154 . The intake valve  155  may operate by elastic deformation to open or close the intake port  154 . That is, the intake valve  155  may be elastically deformed to open the intake port  154  by the pressure of the refrigerant flowing into the compression space  103  through the intake port  154 . 
     The piston  150  may be connected to a mover  135 . The mover  135  may reciprocate forward and backward according to the movement of the piston  150 . The inner stator  134  and the cylinder  140  may be disposed between the mover  135  and the piston  150 . The mover  135  and the piston  150  may be connected to each other by a magnet frame  136  that is formed by detouring the cylinder  140  and the inner stator  134  to the rear. 
     The muffler unit  160  may be coupled to the rear of the piston  150  to reduce a noise generated in the process of sucking the refrigerant into the piston  150 . The refrigerant sucked through the intake pipe  114  may flow into the intake space  102  in the piston  150  via the muffler unit  160 . 
     The muffler unit  160  may include an intake muffler  161  communicating with the accommodation space  101  of the casing  110 , and an inner guide  162  that is connected to a front of the intake muffler  161  and guides the refrigerant to the intake port  154 . 
     The intake muffler  161  may be positioned behind the piston  150 . A rear opening of the intake muffler  161  may be disposed adjacent to the intake pipe  114 , and a front end of the intake muffler  161  may be coupled to the rear of the piston  150 . The intake muffler  161  may have a flow path formed in the axial direction to guide the refrigerant in the accommodation space  101  to the intake space  102  inside the piston  150 . 
     The inside of the intake muffler  161  may include a plurality of noise spaces partitioned by a baffle. The intake muffler  161  may be formed by combining two or more members. For example, a second intake muffler may be press-coupled to the inside of a first intake muffler to form a plurality of noise spaces. In addition, the intake muffler  161  may be formed of a plastic material in consideration of weight or insulation property. 
     One side of the inner guide  162  may communicate with the noise space of the intake muffler  161 , and other side may be deeply inserted into the piston  150 . The inner guide  162  may be formed in a pipe shape. Both ends of the inner guide  162  may have the same inner diameter. The inner guide  162  may be formed in a cylindrical shape. Alternatively, an inner diameter of a front end that is a discharge side of the inner guide  162  may be greater than an inner diameter of a rear end opposite the front end. 
     The intake muffler  161  and the inner guide  162  may be provided in various shapes and may adjust the pressure of the refrigerant passing through the muffler unit  160 . The intake muffler  161  and the inner guide  162  may be formed as one body. 
     The discharge valve assembly  170  may include a discharge valve  171  and a valve spring  172  that is provided on a front side of the discharge valve  171  to elastically support the discharge valve  171 . The discharge valve assembly  170  may selectively discharge the compressed refrigerant in the compression space  103 . Here, the compression space  103  means a space between the intake valve  155  and the discharge valve  171 . 
     The discharge valve  171  may be disposed to be supportable on the front surface of the cylinder  140 . The discharge valve  171  may selectively open and close the front opening of the cylinder  140 . The discharge valve  171  may operate by elastic deformation to open or close the compression space  103 . The discharge valve  171  may be elastically deformed to open the compression space  103  by the pressure of the refrigerant flowing into the discharge space  104  through the compression space  103 . For example, the compression space  103  may maintain a sealed state while the discharge valve  171  is supported on the front surface of the cylinder  140 , and the compressed refrigerant of the compression space  103  may be discharged into an opened space in a state where the discharge valve  171  is spaced apart from the front surface of the cylinder  140 . 
     The valve spring  172  may be provided between the discharge valve  171  and the discharge cover assembly  180  to provide an elastic force in the axial direction. The valve spring  172  may 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 space  103  is equal to or greater than a discharge pressure, the valve spring  172  may open the discharge valve  171  while deforming forward, and the refrigerant may be discharged from the compression space  103  and discharged into a first discharge space  104   a  of the discharge cover assembly  180 . When the discharge of the refrigerant is completed, the valve spring  172  provides a restoring force to the discharge valve  171  and thus can allow the discharge valve  171  to be closed. 
     A process of introducing the refrigerant into the compression space  103  through the intake valve  155  and discharging the refrigerant of the compression space  103  into the discharge space  104  through the discharge valve  171  is described as follows. 
     In the process in which the piston  150  linearly reciprocates in the cylinder  140 , when the pressure of the compression space  103  is equal to or less than a predetermined intake pressure, the intake valve  155  is opened and thus the refrigerant is sucked into a compression space  103 . On the other hand, when the pressure of the compression space  103  exceeds the predetermined intake pressure, the refrigerant of the compression space  103  is compressed in a state in which the intake valve  155  is closed. 
     When the pressure of the compression space  103  is equal to or greater than the predetermined intake pressure, the valve spring  172  deforms forward and opens the discharge valve  171  connected to the valve spring  172 , and the refrigerant is discharged from the compression space  103  to the discharge space  104  of the discharge cover assembly  180 . When the discharge of the refrigerant is completed, the valve spring  172  provides a restoring force to the discharge valve  171  and allows the discharge valve  171  to be closed, thereby sealing a front of the compression space  103 . 
     The discharge cover assembly  180  is installed at the front of the compression space  103 , forms a discharge space  104  for receiving the refrigerant discharged from the compression space  103 , and is coupled to a front of the frame  120  to thereby reduce a noise generated in the process of discharging the refrigerant from the compression space  103 . The discharge cover assembly  180  may be coupled to a front of the first flange portion  122  of the frame  120  while receiving the discharge valve assembly  170 . For example, the discharge cover assembly  180  may be coupled to the first flange portion  122  through a mechanical coupling member. 
     An O-ring  166  may be provided between the discharge cover assembly  180  and the frame  120  to prevent the refrigerant in a gasket  165  for thermal insulation and the discharge space  104  from leaking. 
     The discharge cover assembly  180  may be formed of a thermally conductive material. Therefore, when a high temperature refrigerant is introduced into the discharge cover assembly  180 , heat of the refrigerant may be transferred to the casing  110  through the discharge cover assembly  180  and dissipated to the outside of the compressor. 
     The discharge cover assembly  180  may include one discharge cover, or may be arranged so that a plurality of discharge covers sequentially communicate with each other. When the discharge cover assembly  180  is provided with the plurality of discharge covers, the discharge space  104  may 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 space  104  may include a first discharge space  104   a  between the frame  120  and a first discharge cover  181  coupled to the front side of the frame  120 , a second discharge space  104   b  between the first discharge cover  181  and a second discharge cover  182  that communicates with the first discharge space  104   a  and is coupled to a front side of the first discharge cover  181 , and a third discharge space  104   c  between the second discharge cover  182  and a third discharge cover  183  that communicates with the second discharge space  104   b  and is coupled to a front side of the second discharge cover  182 . 
     The first discharge space  104   a  may selectively communicate with the compression space  103  by the discharge valve  171 , the second discharge space  104   b  may communicate with the first discharge space  104   a,  and the third discharge space  104   c  may communicate with the second discharge space  104   b.  Hence, as the refrigerant discharged from the compression space  103  sequentially passes through the first discharge space  104   a,  the second discharge space  104   b,  and the third discharge space  104   c,  a discharge noise can be reduced, and the refrigerant can be discharged to the outside of the casing  110  through the loop pipe  115   a  and the discharge pipe  115  communicating with the third discharge cover  183 . 
     The drive unit  130  may include the outer stator  131  that is disposed between the shell  111  and the frame  120  and surrounds the body portion  121  of the frame  120 , the inner stator  134  that is disposed between the outer stator  131  and the cylinder  140  and surrounds the cylinder  140 , and the mover  135  disposed between the outer stator  131  and the inner stator  134 . 
     The outer stator  131  may be coupled to the rear of the first flange portion  122  of the frame  120 , and the inner stator  134  may be coupled to the outer circumferential surface of the body portion  121  of the frame  120 . The inner stator  134  may be spaced apart from the inside of the outer stator  131 , and the mover  135  may be disposed in a space between the outer stator  131  and the inner stator  134 . 
     The outer stator  131  may be equipped with a winding coil, and the mover  135  may 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 stator  131  may include a coil winding body  132  surrounding the axial direction in the circumferential direction, and a stator core  133  stacked while surrounding the coil winding body  132 . The coil winding body  132  may include a hollow cylindrical bobbin  132   a  and a coil  132   b  wound in a circumferential direction of the bobbin  132   a.  A cross section of the coil  132   b  may be formed in a circular or polygonal shape and, for example, may have a hexagonal shape. In the stator core  133 , 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 stator  131  may be supported by the first flange portion  122  of the frame  120 , and the rear side thereof may be supported by a stator cover  137 . For example, the stator cover  137  may be provided in a hollow disc shape, a front surface of the stator cover  137  may be supported by the outer stator  131 , and a rear surface thereof may be supported by a resonant spring  118 . 
     The inner stator  134  may be configured by stacking a plurality of laminations on the outer circumferential surface of the body portion  121  of the frame  120  in the circumferential direction. 
     One side of the mover  135  may be coupled to and supported by the magnet frame  136 . The magnet frame  136  has a substantially cylindrical shape and may be disposed to be inserted into a space between the outer stator  131  and the inner stator  134 . The magnet frame  136  may be coupled to the rear side of the piston  150  to move together with the piston  150 . 
     As an example, a rear end of the magnet frame  136  is bent and extended inward in the radial direction to form a first coupling portion  136   a,  and the first coupling portion  136   a  may be coupled to a third flange portion  153  formed behind the piston  150 . The first coupling portion  136   a  of the magnet frame  136  and the third flange portion  153  of the piston  150  may be coupled through a mechanical coupling member. 
     A fourth flange portion  161   a  in front of the intake muffler  161  may be interposed between the third flange portion  153  of the piston  150  and the first coupling portion  136   a  of the magnet frame  136 . Thus, the piston  150 , the muffler unit  160 , and the mover  135  can linearly reciprocate together in a combined state. 
     When a current is applied to the drive unit  130 , 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 stator  131  and a magnetic flux formed by the permanent magnet of the mover  135  to move the mover  135 . At the same time as the reciprocating movement of the mover  135  in the axial direction, the piston  150  connected to the magnet frame  136  may also reciprocate integrally with the mover  135  in the axial direction. 
     The drive unit  130  and the compression units  140  and  150  may be supported by the support springs  116  and  117  and the resonant spring  118  in the axial direction. 
     The resonant spring  118  amplifies the vibration implemented by the reciprocating motion of the mover  135  and the piston  150  and thus can achieve an effective compression of the refrigerant. More specifically, the resonant spring  118  may be adjusted to a frequency corresponding to a natural frequency of the piston  150  and may allow the piston  150  to perform a resonant motion. Further, the resonant spring  118  generates a stable movement of the piston  150  and thus can reduce the generation of vibration and noise. 
     The resonant spring  118  may be a coil spring extending in the axial direction. Both ends of the resonant spring  118  may be connected to a vibrating body and a fixed body, respectively. For example, one end of the resonant spring  118  may be connected to the magnet frame  136 , and the other end may be connected to the back cover  123 . Therefore, the resonant spring  118  may 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 spring  118  may be designed to match a resonant frequency of the mover  135  and the piston  150  during the operation of the compressor  100 , thereby amplifying the reciprocating motion of the piston  150 . However, because the back cover  123  provided as the fixing body is elastically supported by the first support spring  116  in the casing  110 , the back cover  123  may not be strictly fixed. 
     The resonant spring  118  may include a first resonant spring  118   a  supported on the rear side and a second resonant spring  118   b  supported on the front side based on a spring supporter  119 . 
     The spring supporter  119  may include a body portion  119   a  surrounding the intake muffler  161 , a second coupling portion  119   b  that is bent from a front of the body portion  119   a  in the inward radial direction, and a support portion  119   c  that is bent from the rear of the body portion  119   a  in the outward radial direction. 
     A front surface of the second coupling portion  119   b  of the spring supporter  119  may be supported by the first coupling portion  136   a  of the magnet frame  136 . An inner diameter of the second coupling portion  119   b  of the spring supporter  119  may cover an outer diameter of the intake muffler  161 . For example, the second coupling portion  119   b  of the spring supporter  119 , the first coupling portion  136   a  of the magnet frame  136 , and the third flange portion  153  of the piston  150  may be sequentially disposed and then integrally coupled through a mechanical member. In this instance, the description that the fourth flange portion  161   a  of the intake muffler  161  can be interposed between the third flange portion  153  of the piston  150  and the first coupling portion  136   a  of the magnet frame  136 , and they can be fixed together is the same as that described above. 
     The first resonant spring  118   a  may be disposed between a front surface of the back cover  123  and a rear surface of the spring supporter  119 . The second resonant spring  118   b  may be disposed between a rear surface of the stator cover  137  and a front surface of the spring supporter  119 . 
     A plurality of first and second resonant springs  118   a  and  118   b  may be disposed in the circumferential direction of the central axis. The first resonant springs  118   a  and the second resonant springs  118   b  may be disposed parallel to each other in the axial direction, or may be alternately disposed. The first and second resonant springs  118   a  and  118   b  may be disposed at regular intervals in the radial direction of the central axis. For example, three first resonant springs  118   a  and three second resonant springs  118   b  may be provided and may be disposed at intervals of  120  degrees in the radial direction of the central axis. 
     The compressor  100  may include a plurality of sealing members that can increase a coupling force between the frame  120  and the components around the frame  120 . 
     For example, the plurality of sealing members may include a first sealing member that is interposed at a portion where the frame  120  and the discharge cover assembly  180  are coupled and is inserted into an installation groove provided at the front end of the frame  120 , and a second sealing member that is provided at a portion at which the frame  120  and the cylinder  140  are coupled and is inserted into an installation groove provided at an outer surface of the cylinder  140 . The second sealing member can prevent the refrigerant of the gas groove  125   c  between the inner circumferential surface of the frame  120  and the outer circumferential surface of the cylinder  140  from leaking to the outside, and can increase a coupling force between the frame  120  and the cylinder  140 . The plurality of sealing members may further include a third sealing member that is provided at a portion at which the frame  120  and the inner stator  134  are coupled and is inserted into an installation groove provided at the outer surface of the frame  120 . Here, the first to third sealing members may have a ring shape. 
     An operation of the linear compressor  100  described above is as follows. 
     First, when a current is applied to the drive unit  130 , a magnetic flux may be formed in the outer stator  131  by the current flowing in the coil  132   b.  The magnetic flux formed in the outer stator  131  may generate an electromagnetic force, and the mover  135  including 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 piston  150  is directed toward a top dead center (TDC) during a compression stroke, and in a direction (rearward direction) in which the piston  150  is directed toward a bottom dead center (BDC) during an intake stroke. That is, the drive unit  130  may generate a thrust which is a force for pushing the mover  135  and the piston  150  in a moving direction. 
     The piston  150  linearly reciprocating inside the cylinder  140  may repeatedly increase or reduce the volume of the compression space  103 . 
     When the piston  150  moves in a direction (rearward direction) of increasing the volume of the compression space  103 , a pressure of the compression space  103  may decrease. Hence, the intake valve  155  mounted in front of the piston  150  is opened, and the refrigerant remaining in the intake space  102  may be sucked into the compression space  103  along the intake port  154 . The intake stroke may be performed until the piston  150  is positioned in the bottom dead center by maximally increasing the volume of the compression space  103 . 
     The piston  150  reaching 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 space  103 . As the pressure of the compression space  103  increases during the compression stroke, the sucked refrigerant may be compressed. When the pressure of the compression space  103  reaches a setting pressure, the discharge valve  171  is pushed out by the pressure of the compression space  103  and is opened from the cylinder  140 , and the refrigerant can be discharged into the discharge space  104  through a separation space. The compression stroke can continue while the piston  150  moves to the top dead center at which the volume of the compression space  103  is minimized. 
     As the intake stroke and the compression stroke of the piston  150  are repeated, the refrigerant introduced into the accommodation space  101  inside the compressor  100  through the intake pipe  114  may be introduced into the intake space  102  in the piston  150  by sequentially passing the intake guide  116   a,  the intake muffler  161 , and the inner guide  162 , and the refrigerant of the intake space  102  may be introduced into the compression space  103  in the cylinder  140  during the intake stroke of the piston  150 . After the refrigerant of the compression space  103  is compressed and discharged into the discharge space  104  during the compression stroke of the piston  150 , the refrigerant may be discharged to the outside of the compressor  100  via the loop pipe  115   a  and the discharge pipe  115 . 
       FIGS.  3  and  4    are perspective views of partial configuration of a compressor according to an embodiment of the present disclosure.  FIG.  5    is an exploded perspective view of partial configuration of a compressor according to an embodiment of the present disclosure.  FIG.  6    is an exploded perspective view of partial configuration of  FIG.  5   .  FIG.  7    is a side view of partial configuration of a compressor according to an embodiment of the present disclosure.  FIG.  8    is a cross-sectional view of partial configuration of a compressor according to an embodiment of the present disclosure.  FIG.  9    is a plan view of an elastic member according to an embodiment of the present disclosure. 
     Referring to  FIGS.  3  to  9   , a compressor  100  according to an embodiment of the present disclosure may include a cylinder  140 , a piston  150 , an intake valve  155 , a rod  200 , a coupling member  210 , a fixing member  300 , an elastic member  400 , spacers  500  and  600 , and a fastening member  700 , but can be implemented except some of these components and does not exclude additional components. 
       FIGS.  3  to  9    illustrate that the compressor  100  according to an embodiment of the present disclosure can be implemented except the muffler unit  160 , by way of example, but the present disclosure is not limited thereto. 
     The compressor  100  may include the cylinder  140 . The cylinder  140  may be fixed to a frame  120 . The cylinder  140  may be supported by the frame  120 . The cylinder  140  may be disposed in the frame  120 . The cylinder  140  may be formed in a cylindrical shape. The cylinder  140  may extend axially. The piston  150  may be disposed in the cylinder  140 . The cylinder  140  may form a compression space of a refrigerant. 
     The compressor  100  may include the piston  150 . The piston  150  may be disposed at the cylinder  140 . The piston  150  may be disposed inside the cylinder  140 . The piston  150  may reciprocate axially in the cylinder  140 . The piston  150  may be formed in a cylindrical shape. The rod  200  may be disposed in the piston  150 . A body  202  of the rod  200  may be disposed in the piston  150 . The rod  200  may be disposed in a central area of the piston  150 . More specifically, the piston  150  and the rod  200  may share the same axis. The intake valve  155  may be disposed in front of the piston  150 . The fixing member  300  may be disposed outside the piston  150 . The elastic member  400  and the spacers  500  and  600  may be disposed at the rear of the piston  150 . 
     The compressor  100  may include the intake valve  155 . The intake valve  155  may be disposed at the piston  150 . The intake valve  155  may be disposed in front of the piston  150 . The intake valve  155  may seal a front opening of the piston  150 . The intake valve  155  may selectively open and close an intake port  154 . The rod  200  may be coupled to the head portion  151  of the piston  150 . One end  204  of the rod  200  may be disposed at the head portion  151  of the piston  150 . The one end  204  of the rod  200  may be fixed to the head portion  151  of the piston  150 . The one end  204  of the rod  200  may be disposed in a central area of the head portion  151  of the piston  150 . 
     The head portion  151  of the piston  150  may include a rod groove  1552 . The rod groove  1552  may be recessed forward from a rear surface of the head portion  151 . The rod groove  1552  may be formed in a central area of the rear surface of the intake valve  155 . The one end  204  of the rod  200  may be inserted into the rod groove  1552 . The one end  204  of the rod  200  may be fixed to the rod groove  1552 . 
     The rod  200  may be disposed at the piston  150 . The rod  200  may be disposed inside the piston  150 . The rod  200  may extend axially. The rod  200  may be disposed in the central area of the piston  150 . A shaft of the rod  200  may be the same as a shaft of the piston  150 . 
     The rod  200  may be fixed to the head portion  151  of the piston  150 . More specifically, the one end  204  of the rod  200  may be fixed to the head portion  151  of the piston  150 . For example, the one end  204  of the rod  200  may be disposed in the rod groove  1552  of the head portion  151  of the piston  150 . 
     The rod  200  may be connected to the elastic member  400 . More specifically, other end  209  of the rod  200  may be connected to the elastic member  400  through the coupling member  210 . The rod  200  may be formed in a long rod shape. The rod  200  may be formed of a material with elasticity. The rod  200  may distribute a lateral force generated when the piston  150  reciprocates axially. Hence, the present disclosure can prevent damage to the piston  150  and improve lifespan of the product. 
     The rod  200  may include the body  202 . The body  202  may form an appearance of the rod  200 . The body  202  may be formed in a rod shape extending axially. A cross-section of the body  202  may be formed in a circle or oval shape. The body  202  may be disposed inside the piston  150 . The body  202  may be disposed in the central area of the piston  150 . A shaft of the body  202  may be the same as the shaft of the piston  150 . The body  202  may be formed of a material with elasticity. 
     The rod  200  may include a first guide portion  206 . The first guide portion  206  may extend radially from the body  202  of the rod  200 . The first guide portion  206  may be formed between the front end  204  and the central area of the body  202  of the rod  200 . The first guide portion  206  may guide the one end  204  of the rod  200  inserted into the rod groove  1552 . A front part of the first guide portion  206  may be formed in a shape corresponding to a rear part of the rod groove  1552 . The front part of the first guide portion  206  may be disposed at the rear part of the rod groove  1552 . 
     The rod  200  may include a second guide portion  208 . The second guide portion  208  may extend radially from the body  202  of the rod  200 . The second guide portion  208  may be formed between the other end  209  and the central area of the body  202  of the rod  200 . The second guide portion  208  may guide the other end  209  of the rod  200  to be coupled to the coupling member  210 . A rear part of the second guide portion  208  may be formed in a shape corresponding to a front part of the coupling member  210 . The rear part of the second guide portion  208  may be disposed at the front part of the coupling member  210 . 
     The compressor  100  may include the coupling member  210 . The coupling member  210  may be disposed in a rear area of the piston  150 . At least a part of the coupling member  210  may be disposed inside the piston  150 . The coupling member  210  may pass through the elastic member  400  and the inner spacer  600 . A rear part  212  of the coupling member  210  may pass through the elastic member  400  and the inner spacer  600  and may be coupled to a first fastening member  710 . 
     The coupling member  210  may be coupled to the rod  200 . The other end  209  of the rod  200  may be coupled to a front part  211  of the coupling member  210 . One side of the coupling member  210  may be formed in a shape corresponding to other end of the rod  200 . The front part  211  of the coupling member  210  may include a groove into which the other end  209  of the rod  200  is inserted. The groove of the coupling member  210  into which the other end  209  of the rod  200  is inserted may be formed in a central area of the front part  211  of the coupling member  210 . 
     A radius of the coupling member  210  may be formed to be larger than a radius of the rod  200 . The radius of the coupling member  210  may be formed to be larger than a radius of a central area of the rod  200 . More specifically, a radius of the rear part  212  of the coupling member  210  may be formed to be larger than a radius of the body  202  of the rod  200 . Through this, coupling stability between the elastic member  400  and the inner spacer  600  can be improved. 
     An embodiment of the present disclosure describes that the rod  200  and the coupling member  210  are separately formed and coupled to each other, by way of example. However, the rod  200  and the coupling member  210  may be integrally formed, and the other end  209  of the rod  200  may pass through an inner hole  203  of an inner portion  402  of the elastic member  400  and may be directly coupled to the first fastening member  710  without the coupling member  210 . 
     The compressor  100  may include the fixing member  300 . The fixing member  300  may be disposed outside the piston  150 . At least a portion of the fixing member  300  may radially overlap the piston  150 . The fixing member  300  may be formed in a circular band shape. The elastic member  400  may be coupled to the fixing member  300 . An outer portion  404  of the elastic member  400  may be coupled to the fixing member  300 . Specifically, the outer portion  404  of the elastic member  400  may be coupled to the fixing member  300  through a second fastening member  720 . The spacers  500  and  600  may be coupled to the fixing member  300 . The outer spacer  500  may be coupled to the fixing member  300 . Specifically, the outer spacer  500  may be coupled to the fixing member  300  through the second fastening member  720 . In this case, the second fastening member  720  may be coupled to a fastening hole  312  of the fixing member  300 . For example, the second fastening member  720  may be screw-coupled to the fastening hole  312  of the fixing member  300 , but is not limited thereto. The number of fastening holes  312  of the fixing member  300  may be variously changed depending on the number of the second fastening members  720 . 
     The fixing member  300  may include an extension  310 . The extension  310  may protrude forward from the fixing member  300 . The extension  310  may radially overlap the piston  150 . The extension  310  may radially overlap the other end  209  of the rod  200 . The extension  310  may radially overlap the front part  211  of the coupling member  210 . The extension  310  may axially overlap an outer hole  405  of the outer portion  404  of the elastic member  400 . The extension  310  may axially overlap a second hole  504  of the outer spacer  500 . The extension  310  may include the fastening hole  312  to which the second fastening member  720  is coupled. Since the length in the axial direction to which the second fastening member  720  is coupled can be extended through the extension  310 , coupling stability by the second fastening member  720  can be improved. 
     The compressor  100  may include the elastic member  400 . The elastic member  400  may be disposed at the rear of the piston  150 . The elastic member  400  may be disposed at the rear of the rod  200 . The elastic member  400  may radially overlap the coupling member  210 . The elastic member  400  may radially overlap the outer spacer  500 . The elastic member  400  may be connected to the fixing member  300  together with the outer spacer  500  through the second fastening member  720 . 
     The elastic member  400  may radially overlap the inner spacer  600 . The elastic member  400  may be coupled to the inner spacer  600 . The elastic member  400  may be connected to the other end  209  of the rod  200  through the inner spacer  600  and the coupling member  210 . The elastic member  400  may have structural elasticity. Alternatively, the elastic member  400  may be formed of a material with elasticity. The elastic member  400  may include a leaf spring. Through this, the elastic member  400  may elastically support the rod  200  and/or the piston  150 . 
     The elastic member  400  may include the inner portion  402 . The inner portion  402  may radially overlap the piston  150 . The inner portion  402  may be connected to the rod  200 . The inner portion  402  may be coupled to the inner spacer  600 . The inner portion  402  may be coupled to the coupling member  210 . The inner portion  402  may be penetrated by the rear part  212  of the coupling member  210 . The inner portion  402  may be connected to the other end  209  of the rod  200  through the coupling member  210 . An inner hole  403  may be formed in the inner portion  402 . The inner hole  403  may be formed in a central area of the inner portion  402 . 
     The elastic member  400  may include the inner hole  403 . The inner hole  403  may be formed in the inner portion  402 . The inner hole  403  may be formed in the central area of the inner portion  402 . The inner hole  403  may axially overlap a first hole  604  of the inner spacer  600 . The inner hole  403  may axially overlap the piston  150 . The inner hole  403  may axially overlap the rod  200 . The inner hole  403  may be coupled to the coupling member  210 . A radius of the inner hole  403  may have a size corresponding to the radius of the rear part  212  of the coupling member  210 . The inner hole  403  may be penetrated by the rear part  212  of the coupling member  210 . 
     The elastic member  400  may include the outer portion  404 . The outer portion  404  may be disposed outside the inner portion  402 . The outer portion  404  may be spaced apart from the inner portion  402 . The outer portion  404  may not axially overlap the piston  150 . The outer portion  404  may be connected to the fixing member  300 . The outer portion  404  may be coupled to the outer spacer  500 . The outer portion  404  may be connected to the fixing member  300  through the second fastening member  720 . 
     The elastic member  400  may include the outer hole  405 . The outer hole  405  may be formed in the outer portion  404 . The outer hole  405  may be connected to the fixing member  300 . The outer hole  405  may axially overlap the second hole  504  of the outer spacer  500 . The outer hole  405  may be penetrated by the second fastening member  720 . The outer hole  405  may include a plurality of outer holes that is radially disposed around the center of the elastic member  400 . An embodiment of the present disclosure describes that the three outer holes  405  are formed in the outer portion  404 , by way of example, but is not limited thereto. For example, the number of outer holes  405  can be variously changed. 
     The elastic member  400  may include a connection portion  406 . The connection portion  406  may connect the inner portion  402  and the outer portion  404 . The connection portion  406  may be disposed between the inner portion  402  and the outer portion  404 . The connection portion  406  may be formed in a spiral shape. The connection portion  406  may include a plurality of connection members formed in a spiral shape. The plurality of connection members may be spaced apart from each other. The plurality of connection members may have shapes corresponding to each other. A separation space  407  may be formed in a space between the plurality of connection members. Through this, the elastic member  400  can have structural elasticity. 
     The elastic member  400  may be axially spaced apart from the piston  150 . A rear surface of the piston  150  and a front surface of the elastic member  400  may be axially spaced apart from each other. For example, a first elastic member  410  and the rear surface of the piston  150  may be axially spaced apart from each other. Through this, the refrigerant at the rear of the piston  150  may be introduced into the piston  150  via the separation space  407  between the plurality of connection members and the space between the rear surface of the piston  150  and the elastic member  400 . 
     The elastic member  400  may include the first elastic member  410 . The first elastic member  410  may be disposed at the rear of the piston  150 . The first elastic member  410  may be disposed at the rear of the rod  200 . The first elastic member  410  may be disposed at the rear of the fixing member  300 . The first elastic member  410  may be disposed in front of a second elastic member  420 . The first elastic member  410  may be axially spaced apart from the second elastic member  420 . The first elastic member  410  may be formed in a shape corresponding to a shape of the second elastic member  420 . The first elastic member  410  may be connected to the rod  200  through the coupling member  210 . The first elastic member  410  may be connected to the fixing member  300  through the second fastening member  720 . 
     The elastic member  400  may include the second elastic member  420 . The second elastic member  420  may be disposed at the rear of the first elastic member  410 . The second elastic member  420  may be disposed in front of a third elastic member  430 . The second elastic member  420  may be axially spaced apart from the third elastic member  430 . The second elastic member  420  may be formed in a shape corresponding to a shape of the third elastic member  430 . The second elastic member  420  may be connected to the rod  200  through the coupling member  210 . The second elastic member  420  may be connected to the fixing member  300  through the second fastening member  720 . 
     The elastic member  400  may include the third elastic member  430 . The third elastic member  430  may be disposed at the rear of the second elastic member  420 . The third elastic member  430  may be axially spaced apart from the second elastic member  420 . The third elastic member  430  may be connected to the rod  200  through the coupling member  210 . The third elastic member  430  may be connected to the fixing member  300  through the second fastening member  720 . 
     An embodiment of the present disclosure describes that the first to third elastic members  410 ,  420 , and  430  have the same shape, by way of example. However, at least one of the first elastic member  410 , the second elastic member  420 , and the third elastic member  430  may have a different shape from the other elastic member. 
     An embodiment of the present disclosure describes that the number of elastic members  400  is three, by way of example. However, an embodiment of the present disclosure describes is not limited thereto and can be variously changed as long as the number of elastic members  400  is two or more. 
     The compressor  100  may include the spacers  500  and  600 . The spacers  500  and  600  may be disposed between the first elastic member  410  and the second elastic member  420 . The spacers  500  and  600  may be disposed between the second elastic member  420  and the third elastic member  430 . The spacers  500  and  600  may separate the first elastic member  410  from the second elastic member  420  and separate the second elastic member  420  from the third elastic member  430 . Through this, each of the plurality of elastic members  410 ,  420 , and  430  can elastically support the piston  150  and/or the rod  200 . 
     The spacers  500  and  600  may be insert-injected with the elastic member  400 . The spacers  500  and  600  may be insert-injected with the first elastic member  410 , the second elastic member  420 , and the third elastic member  430 . Through this, the cost of the product can be reduced by reducing the number of components, and it is easy to manage and transport through modularization. The spacers  500  and  600  may be formed of a plastic material. Through this, the reliability of the product can be improved by removing the metal product between the elastic members  400 . 
     The spacers  500  and  600  may include the outer spacer  500 . The outer spacer  500  may be insert-injected with an outer portion of the first elastic member  410 , an outer portion of the second elastic member  420 , and an outer portion of the third elastic member  430 . The outer spacer  500  may cover a front surface, an outer surface, and a rear surface of the outer portion of the first elastic member  410 , a front surface, an outer surface, and a rear surface of the outer portion of the second elastic member  420 , and an outer surface, a front surface, and a rear surface of the outer portion of the third elastic member  430 . 
     The outer spacer  500  may be formed in a cylindrical shape in which an opening is formed in the center. The outer spacer  500  may include an elastic groove  502  in which the outer surface of the outer portion of the first elastic member  410 , the outer surface of the outer portion of the second elastic member  420 , and the outer surface of the outer portion of the third elastic member  430  are disposed. The elastic groove  502  may be formed in an inner surface of the outer spacer  500 . 
     The outer spacer  500  may include the second hole  504 . The second hole  504  may extend axially. The second hole  504  may axially overlap an outer hole of the outer portion of the first elastic member  410 , an outer hole of the outer portion of the second elastic member  420 , and an outer hole of the outer portion of the third elastic member  430 . The second hole  504  may be penetrated by the second fastening member  720 . The second hole  504  may include a plurality of second holes that are spaced apart from each other. An embodiment of the present disclosure describes that the plurality of second holes are three, by way of example. However, the number of second holes can be variously changed based on the number of outer hole of the outer portion of the first elastic member  410 , outer hole of the outer portion of the second elastic member  420 , and outer hole of the outer portion of the third elastic member  430 . 
     The spacers  500  and  600  may include the inner spacer  600 . The inner spacer  600  may be disposed inside the outer spacer  500 . The inner spacer  600  may be spaced apart from the outer spacer  500 . The inner spacer  600  may be insert-injected with an inner portion of the first elastic member  410 , an inner portion of the second elastic member  420 , and an inner portion of the third elastic member  430 . The inner spacer  600  may cover a front surface, an outer surface, and a rear surface of the inner portion of the first elastic member  410 , a front surface, an outer surface, and a rear surface of the inner portion of the second elastic member  420 , and a front surface, an outer surface, and a rear surface of the inner portion of the third elastic member  430 . 
     The inner spacer  600  may include the first hole  604 . The first hole  604  may be formed in a central area of the inner spacer  600 . The first hole  604  may extend axially. The first hole  604  may axially overlap an inner hole of the inner portion of the first elastic member  410 , an inner hole of the inner portion of the second elastic member  420 , and an inner hole of the inner portion of the third elastic member  430 . The first hole  604  may axially overlap the rod  200 . The first hole  604  may be penetrated by the coupling member  210 . The rear part  212  of the coupling member  210  may be disposed in the first hole  604 . A radius of the first hole  604  may have a size corresponding to the radius of the rear part  212  of the coupling member  210 . 
     The compressor  100  may include the fastening member  700 . The fastening member  700  may include the first fastening member  710 . The first fastening member  710  may be disposed at the rear of the inner spacer  600 . The first fastening member  710  may be coupled to the coupling member  210 . The first fastening member  710  may be coupled to the rear part  212  of the coupling member  210  passing through the inner hole  403  of the inner portion  402  of the elastic member  400  and the first hole  604  of the inner spacer  600 . For example, the first fastening member  710  may be screw-coupled to the rear part  212  of the coupling member  210  passing through the inner portion  402  of the elastic member  400  and the first hole  604  of the inner spacer  600 . The first fastening member  710  may fix the other end of the rear part  212  of the coupling member  210  to a rear surface of the inner spacer  600 . Through this, the first fastening member  710  can couple the coupling member  210 , the inner portion  402  of the elastic member  400 , and the inner spacer  600 . 
     The fastening member  700  may include the second fastening member  720 . The second fastening member  720  may pass through the outer hole  405  of the outer portion  404  of the elastic member  400  and the second hole  504  of the outer spacer  500  and may be coupled to the fastening hole  312  of the fixing member  300 . For example, the second fastening member  720  may pass through the outer hole  405  of the outer portion  404  of the elastic member  400  and the second hole  504  of the outer spacer  500  and may be screw-coupled to the fastening hole  312  of the fixing member  300 . Through this, the second fastening member  720  can couple the outer portion  404  of the elastic member  400  and the outer spacer  500  to the fixing member  300 . The second fastening member  720  may include a plurality of second fastening members that is radially disposed around the central area of the elastic member  400 . An embodiment of the present disclosure describes that the plurality of second fastening members are three, by way of example. However, the number of second fastening members is not limited thereto and can be variously changed. 
       FIGS.  10  and  11    are perspective views of an elastic member and a spacer according to another embodiment of the present disclosure. 
     With reference to  FIGS.  10  and  11   , another embodiment of the present disclosure is described below. 
     In another embodiment of the present disclosure, the inner spacer  600  may be changed to second spacers  610  and  620 . The second spacers  610  and  620  may be disposed on a front surface and a rear surface of an inner portion  402  of an elastic member  400 . The second spacers  610  and  620  may be coupled to the front surface and the rear surface of the inner portion  402  of the elastic member  400  using an adhesive, etc. The second spacers  610  and  620  may be disposed adjacent to an inner hole  404  of the inner portion  402  of the elastic member  400 . The second spacers  610  and  620  may be formed in a circular band shape. The second spacers  610  and  620  may be formed in a ring shape. The second spacers  610  and  620  may be formed of a plastic material. 
       FIGS.  12  and  13    are perspective views of an elastic member and a spacer according to yet another embodiment of the present disclosure. 
     With reference to  FIGS.  12  and  13   , yet another embodiment of the present disclosure is described below. 
     In yet another embodiment of the present disclosure, the inner spacer  600  may be changed to second spacers  610  and  620 . The second spacers  610  and  620  may be disposed on a front surface and a rear surface of an inner portion  402  of an elastic member  400 . The second spacers  610  and  620  may be coupled to the front surface and the rear surface of the inner portion  402  of the elastic member  400  using an adhesive, etc. The second spacers  610  and  620  may be disposed adjacent to an inner hole  403  of the inner portion  402  of the elastic member  400 . The second spacers  610  and  620  may be formed in a circular band shape. The second spacers  610  and  620  may be formed in a ring shape. The second spacers  610  and  620  may be formed of a plastic material. 
     In yet another embodiment of the present disclosure, the outer spacer  500  may be changed to third spacers  510  and  520 . The third spacers  510  and  520  may be disposed on a front surface and a rear surface of an outer portion  404  of the elastic member  400 . The third spacers  510  and  520  may be coupled to the front surface and the rear surface of the outer portion  404  of the elastic member  400  using an adhesive, etc. The third spacers  510  and  520  may be disposed adjacent to an outer hole  405  of the outer portion  404  of the elastic member  400 . The third spacers  510  and  520  may be formed in a circular band shape. The third spacers  510  and  520  may be formed in a ring shape. The third spacers  510  and  520  may be formed of a plastic material. 
       FIG.  14    is a perspective view of an elastic member and a spacer according to still yet another embodiment of the present disclosure. 
     With reference to  FIG.  14   , still yet another embodiment of the present disclosure is described below. 
     In still yet another embodiment of the present disclosure, the inner spacer  600  may be changed to a second spacer  610 . The second spacer  610  may be disposed on one surface of an inner portion  402  of an elastic member  400 . The second spacer  610  may be coupled to one surface of the inner portion  402  of the elastic member  400  using an adhesive, etc. Specifically, the second spacer  610  may be coupled to one surface of a third elastic member  430  and disposed between a second elastic member  420  and the third elastic member  430 , and may be coupled to one surface of the second elastic member  420  and disposed between a first elastic member  410  and the second elastic member  420 . The second spacer  610  may be disposed adjacent to an inner hole  404  of the inner portion  402  of the elastic member  400 . The second spacer  610  may be formed in a circular band shape. The second spacer  610  may be formed in a ring shape. The second spacer  610  may be formed of a plastic material. 
     In still yet another embodiment of the present disclosure, the outer spacer  500  may be changed to a third spacer  510 . The third spacer  510  may be disposed on one surface of an outer portion  404  of the elastic member  400 . The third spacer  510  may be coupled to one surface of the outer portion  404  of the elastic member  400  using an adhesive, etc. Specifically, the third spacer  510  may be coupled to one surface of the third elastic member  430  and disposed between the second elastic member  420  and the third elastic member  430 , and may be coupled to one surface of the second elastic member  420  and disposed between the first elastic member  410  and the second elastic member  420 . The third spacer  510  may be disposed adjacent to an outer hole  405  of the outer portion  404  of the elastic member  400 . The third spacer  510  may be formed in a circular band shape. The third spacer  510  may be formed in a ring shape. The third spacer  510  may be formed of a plastic material. 
     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.