Patent Publication Number: US-9850893-B2

Title: Reciprocating compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2013-0166083, filed in Korea on Dec. 27, 2013, the contents of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     A reciprocating compressor, and more particularly, to a reciprocating compressor having multiple shells is disclosed herein. 
     2. Background 
     In general, a reciprocating compressor is a compressor in which a piston linearly reciprocates within a cylinder to suck, compress, and discharge a refrigerant. The reciprocating compressor may be classified as a connection type reciprocating compressor and a vibration type reciprocating compressor according to a drive scheme of a piston forming a component of a compression mechanism. 
     In the connection type reciprocating compressor, a piston is connected to a rotational shaft of a rotary motor by a connecting rod and reciprocates within a cylinder to compress a refrigerant. In the vibration type reciprocating compressor, a piston is connected to a mover of a reciprocating motor, so as to vibrate and reciprocate within a cylinder to compress a refrigerant. Embodiments disclosed herein relate to a vibration type reciprocating compressor, and hereinafter, the vibration type linear compressor will be simply referred to as a reciprocating compressor. 
     The reciprocating compressor may be classified as a fixed type reciprocating compressor, in which a frame that supports a stator of a reciprocating motor, and a cylinder of a compression mechanism is fixed to an inner circumferential surface of a shell, and a movable reciprocating compressor, in which a frame is spaced apart from an inner circumferential surface of a shell. In the fixed type reciprocating compressor, vibration transmitted from an exterior of the shell or vibration generated in an interior of the shell may be directly transmitted to the interior of the shell or the exterior of the shell, increasing vibration noise of the compressor. In contrast, in the movable reciprocating compressor, a support spring may be installed between a shell and a compression mechanism, and thus, vibration transmitted from the exterior of the shell or vibration generated in the interior of the shell may be absorbed by the support spring, rather than being directly transmitted to the interior or exterior of the shell, attenuating vibration noise of the compressor. 
       FIG. 1  is a cross-sectional view of a related art movable reciprocating compressor. As illustrated, in the related art reciprocating compressor, a compressor body C that compresses a refrigerator in an internal space  11  of an airtight shell  10  is elastically supported by a plurality of support springs  61  and  62 . 
     The compressor body C includes a reciprocating motor  30  installed in the internal space  11  of the shell  10 , in which a mover  32  reciprocates, and a compressor mechanism  40 , in which a piston  42  is coupled to the mover  32  of the reciprocating motor  30  and reciprocates in a cylinder  41  to compress a refrigerant. The plurality of support springs  61  and  62  is formed as plate springs having an identical natural frequency and installed between the compressor body C and an inner circumferential surface of the shell  10 . 
     In  FIG. 1 , reference numeral  12  denotes a suction pipe, reference numeral  13  denotes a discharge pipe, reference numeral  20  denotes a frame, reference numeral  31  denotes a stator, reference numeral  31   a  denotes a plurality of stator blocks, reference numeral  31   b  denotes a plurality of pole blocks, reference numeral  35  denotes a coil, reference numeral  32   a  denotes a magnet holder, reference numeral  32   b  denotes a magnet, reference numeral  43  denotes a suction valve, reference numeral  44  denotes a discharge valve, reference numeral  45  denotes a valve spring, reference numeral  46  denotes a discharge cover, reference numerals  51  and  52  denote resonance springs, reference numeral  53  denotes a support bracket that supports the resonance springs, reference numeral  70  denotes a gas bearing, reference letter F denotes a suction flow path, reference numeral S 1  denotes a compression space, and reference numeral S 2  denotes a discharge space. 
     In the related art reciprocating compressor discussed above, when power is applied to the reciprocating motor  30 , the mover  32  of the reciprocating motor  30  reciprocates with respect to the stator  31 . Then, the piston  42  coupled to the mover  32  linearly reciprocates within the cylinder  41  to suck, compress, and discharge a refrigerant. 
     Here, the compressor body C including the reciprocating motor  30  and the compression mechanism  40  is elastically supported by the plurality of support springs  61  and  62  with respect to the shell  10 , absorbs vibration transmitted from an exterior of the shell  10  and vibration generated in an interior of the shell  10  to attenuate vibration noise of the compressor. 
     However, in the related art reciprocating compressor discussed above, as vibration transmitted from the exterior of the shell  10  or vibration generated in the interior of the shell  10  are attenuated only by the support springs  61  and  62 , vibration noise of the compressor cannot be sufficiently attenuated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein: 
         FIG. 1  is a cross-sectional view of a related art reciprocating compressor; 
         FIG. 2  is a cross-sectional view of a reciprocating compressor according to an embodiment; 
         FIG. 3  is a cross-sectional view illustrating an embodiment of a vibration absorbing member forming an outer shell, taken along line III-III of  FIG. 2 ; 
         FIG. 4  is a cross-sectional illustrating another embodiment of a vibration absorbing member forming an outer shell, taken alone line of  FIG. 2 ; 
         FIGS. 5 through 8  are cross-sectional views illustrating embodiments of a vibration absorbing member, in which a portion “A” of  FIG. 3  is enlarged; 
         FIG. 9  is a graph illustrating an effect of reducing vibration of a vibration absorbing member of the reciprocating compressor of  FIG. 2 ; and 
         FIG. 10  is a cross-sectional view illustrating another embodiment of a reciprocating compressor. 
     
    
    
     DETAILED DESCRIPTION 
     Description will now be given in detail of embodiments, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and repetitive description thereof has been omitted. 
     Hereinafter, a reciprocating compressor according to embodiments will be described with reference to the accompanying drawings. 
       FIG. 2  is a cross-sectional view of a reciprocating compressor according to an embodiment. As illustrated in  FIG. 2 , in the reciprocating compressor according to an embodiment, a frame  120  may be installed in an interior of a hermetically sealed shell  110 , and a stator  131  of a reciprocating motor  130  may be installed in the frame  120 . 
     In the reciprocating motor  130 , a coil  135  may be insertedly coupled to a stator  131 , and an air gap may be formed only at one side based on the coil  135 . A mover  132  may include a plurality of magnets  132   b , which may be inserted in the air gap of the stator  131  and reciprocate in a movement direction of a piston. 
     The stator  131  may include a plurality of stator blocks  131   a , and a plurality of pole blocks  131   b , respectively, coupled to sides of the stator blocks  131   a  to form the air gap (no reference numeral given) together with the plurality of stator blocks  131   a  The plurality of stator blocks  131   a  and the plurality of pole blocks  131   b  may be formed by laminating a plurality of thin stator cores one upon another, so that, when projected in an axial direction, the plurality of stator blocks  131   a  and the plurality of pole blocks  131   b  may have a circular arc shape. The plurality of stator blocks  131   a  may have a recess ( ) shape when projected in the axial direction, and the plurality of pole block  131   b  may have a rectangular shape ( ) shape when projected in the axial direction. 
     The mover  132  may include a magnet holder  132   a , and the plurality of magnets  132   b  coupled to an outer circumferential surface of the magnet holder  132   a  in a circumferential direction to form magnetic flux together with the coil  35 . The magnet holder  132   a  may be formed of a non-magnetic material to prevent leakage of magnetic flux; however, embodiments are not limited thereto. Alternatively, the magnet holder  132   a  may be formed of a magnetic material. An outer circumferential surface of the magnet holder  132   a  may have a circular shape to allow the plurality of magnets  132   b  to be attached thereto in a line contact manner. A magnet installation recess (not shown) may be formed in a band shape on an outer circumferential surface of the magnet holder  132   a  to allow the plurality of magnets  132   b  to be inserted therein and supported in a movement direction. 
     The plurality of magnets  132   b  may have a hexahedral shape and may be individually attached to the outer circumferential surface of the magnet holder  132   a . When the plurality of magnets  132   b  is individually attached to the outer circumferential surface of the magnet holder  132   a , the outer circumferential surfaces of the plurality of magnets  132   b  may be fixedly covered by a support member (not shown), such as a separate fixing ring, or a tape formed of a composite material, for example. 
     The plurality of magnets  132   b  may be continuously attached to the outer circumferential surface of the magnet holder  132   a  in a circumferential direction. Alternatively, the stator  131  may include the plurality of stator blocks  131   a  arranged to be spaced apart from one another by a predetermined gap in the circumferential direction, and the plurality of magnets  132   b  may be attached at a predetermined gap, namely, a gap equal to the gap between the plurality of stator blocks  131   a , in a circumferential direction on the outer circumferential surface of the magnet holder  132   a , in order to minimize usage of the plurality of magnets  132   b.    
     In order to ensure a stable reciprocating movement, the plurality of magnets  132   b  may be formed such that a length thereof of each in a movement direction is not smaller than a length of the air gap in the movement direction, specifically, greater than the length of the air gap in the movement direction, and disposed such that at least one end of each magnet  132   b  in the movement direction is positioned within the air gap at an initial position or during an operation. Only one magnet may be disposed in the movement direction, or a plurality of magnets may be disposed in the movement direction. Each magnet  132   b  may be disposed such that an N pole and an S pole correspond to the movement direction. 
     In the reciprocating motor  130 , the stator  131  may have a single air gap, or the stator  131  may have an air gap (not shown) on both sides thereof in a reciprocating direction based on the coil  135 . In this case, the mover  132  may be formed in the same manner as that of the previous embodiment. 
     A cylinder  141  forming a compression mechanism  140  together with the stator  131  of the reciprocating motor  130  may be fixed to the frame  120 , and a piston  142  may be inserted in the cylinder  141 , such that the piston  142  reciprocates therein. The piston  142  may be coupled to the mover  132 , such that the piston  142  reciprocates together with the mover  132  of the reciprocating motor  130 . Resonance springs  151  and  152  that induce the piston  142  to make a resonant movement may be installed on both sides of the piston  142  in the movement direction, respectively. 
     A compression space S 1  may be formed in the cylinder  141 . A suction flow path F may be formed in the piston  142 . A suction valve  143  to open and close the suction flow path F may be installed at an end of the suction flow path F. A discharge valve  144  to open and close the compression space S 1  of the cylinder  141  may be installed in or at a front end surface of the cylinder  141 , and a discharge cover  146  to fix the cylinder  141  to the frame  120  and that accommodates the discharge valve  144  may be coupled to the frame  120 . In  FIG. 2 , reference numeral  52  denotes a discharge space. 
     A fluid bearing  170  may be formed in the cylinder  141 . The fluid bearing  170  may include a plurality of rows of gas holes (not shown) that penetrates from a front end surface of the cylinder  141  to an inner circumferential surface thereof. The fluid bearing  170  may have any structure as long as it guides a refrigerant discharged to a discharge cover  146 , to between the cylinder  141  and the piston  142  to support the cylinder  141  and the piston  142 . 
     A first support spring  161  that supports compressor body C in a horizontal direction may be installed between the discharge cover  146  and a front side of the shell  110 , and a second support spring  162  that supports the compressor body C in the horizontal direction may be installed between the resonance spring, specifically, the spring bracket  153  that supports the resonance spring, and the rear side of the shell  110 . 
     The first support spring  161  and the second support spring  162  may be configured as plate springs, as illustrated in  FIG. 2 . For example, a first fixed portion  161   a  fixed to the front side of the shell  110  may be formed at an edge of the first support spring  161 , and a second fixed portion  161   b  fixed to a front side of the discharge cover  146  may be formed at a center of the first support spring  161 . An elastic portion  161   c  cut in a spiral shape may be formed between the first fixed portion  161   a  and the second fixed portion  161   b.    
     A first fixed portion  162   a  fixed to a rear side of the shell  110  may be formed at an edge of the second spring  162 , and a second fixed portion  162   b  fixed to the support bracket  153  that supports the resonance spring  152  may be formed at a center of the second spring  162 . An elastic portion  162   c  cut in a spiral shape may be formed between the first fixed portion  162   a  and the second fixed portion  162   b.    
     In  FIG. 2 , reference numeral  101  denotes an internal space, reference numeral  102  denotes a suction pipe, reference numeral  103  denotes a discharge pipe, reference numeral  145  denotes a valve spring, reference numeral  111  denotes a body shell, reference numeral  112  denotes a front shell, reference numeral  113  denotes a rear shell, and reference numeral  200  denotes a vibration absorbing member. 
     An operation of reciprocating compressor according to this embodiment will be described hereinbelow. 
     When power is applied to the coil  135  of the reciprocating motor  130 , the plurality of magnets  132   b  provided in the mover  132  of the motor  130  may generate bi-directional induced magnetism together with the coil  135 , whereby the mover  132  may reciprocate with respect to the stator  131  by the induced magnetism and elastic force of the resonance springs  151  and  152 . Then, the piston  142  coupled to the mover  32  may linearly reciprocate within the cylinder  141  to suck a refrigerant, compress the refrigerant, and subsequently discharge the compressed refrigerant to outside of the compressor. 
     At this time, the mover  132  of the reciprocating motor  130  may reciprocate in a horizontal direction with respect to the stator  131 , and at the same time, the piston  142  may reciprocate in the horizontal direction with respect to the cylinder  141 , generating vibration in the horizontal direction. The vibration may be attenuated by the first support spring  161  and the second support spring  162  that elastically support the compressor body C with respect to the shell  110 , and thus, vibration generated in the interior of the shell  110  and transmitted to the exterior of the shell  110  may be attenuated, thus reducing vibration noise of the compressor. Of course, vibration transmitted through the shell  110  from the exterior of the shell  110  may also be attenuated by the first support spring  161  and the second support spring  162 , reducing vibration noise of the compressor. 
     However, vibration transmitted from the exterior of the shell  110  or vibration generated in the interior of the shell  110  may not be sufficiently attenuated by only the first support spring  161  and the second support spring  162 . Thus, in this embodiment, vibration absorbing member  200  forming an outer shell or an inner shell may be installed on an outer circumferential surface or an inner circumferential surface of the shell  110  in order to form a frictional damping and noise insulating layer between the shell  110  and the vibration absorbing member  200  or between layers of the vibration absorbing member  200  to thus reduce noise. When the vibration absorbing member  200  is installed on the outer circumferential surface of the shell  110 , the shell  110  forms an inner shell, and the vibration absorbing member  200  forms an outer shell, and when the vibration absorbing member  200  is installed on an inner circumferential surface of the shell  110 , the shell  110  forms an outer shell and the vibration absorbing member  200  forms an inner shell  110  will be described. Hereinafter, an example in which the vibration absorbing member  200  is installed on the outer circumferential surface of the shell will be described. Installation of the vibration absorbing member  200  on the inner circumferential surface of the shell  110  and installation of the vibration absorbing member  200  on the outer circumferential surface of the shell  10  may be the same or similar in construction or operational effects. 
       FIG. 3  is a cross-sectional view illustrating an embodiment of a vibration absorbing member forming an outer shell, taken along line ill-Ill of  FIG. 2 .  FIG. 4  is a cross-sectional illustrating another embodiment of a vibration absorbing member forming an outer shell, taken alone line III-III of  FIG. 2 .  FIGS. 5 through 8  are cross-sectional views illustrating embodiments of a vibration absorbing member, in which a portion “A” of  FIG. 3  is enlarged to be shown. 
     As illustrated in  FIGS. 3, 4, and 5 through 8 , the shell of the reciprocating compressor according to embodiments may include body shell  111  having a cylindrical shape, and front shell  112  and rear shell  113 , which may be, for example, welded, to a front end and a rear end of the body shell  110  in order to cover a front side and a rear side of the body shell  111 , respectively. The first support spring  161  and the second spring  162  as described above may be inserted between the body shell  111  and the front shell  112  or between the body shell  111  and the rear shell  113 , and may be, for example, welded together, respectively. Step surfaces (no reference numerals are given) may be formed on both ends of the front and rear of the body shell  110  to allow the first support spring  161  and the second support spring  162  to be mounted thereon. 
     In a state in which the first support spring  161  is mounted on the front side step surface, the front shell  112  may be mounted on the first support spring  161 , and may be, for example, welded to couple the body shell  111 , the first support spring  161 , and the front shell  112 . In a state in which the second support spring  162  is mounted on the rear side step surface, the rear shell  113  may be mounted on the second support spring  162 , and may be, for example, welded to couple the body shell  111 , the second support spring  162 , and the rear shell  113 . 
     The vibration absorbing member  200  may be formed as a thin plate member which may be wound around on the body shell  111  at least one or more times. The vibration absorbing member  200  may use a plate body having a thickness greater than a thickness the shell  110 , but in such a case, it may be difficult to wind the vibration absorbing member  200 . Thus, as illustrated in  FIGS. 2 through 8 , a member having a thickness equal to or smaller than a thickness of the shell  100  may be used as the vibration absorbing member  200 . 
     As the vibration absorbing member  200  may be formed by winding a thin plate member a plurality of times (forming a plurality of layers), the vibration absorbing member  200  may be formed of a material having a weight smaller than a weight of the shell  100  to reduce a weight of the compressor. Also, the vibration absorbing member  200  may be formed of a material having a greater stiffness than a stiffness of the shell  100  in order to prevent sagging, for example. 
     Also, as a number of windings of the vibration absorbing member  200  increases, noise insulating layers may be increased to further effectively reduce vibration of the compressor. However, if the number of layers of the vibration absorbing member  200  is too excessive, the overall weight of the compressor, as well as material costs, may increase, and thus, a total thickness of the vibration absorbing member  200  may be smaller than or equal to the thickness of the shell  110  of the compressor, or may be equal to or smaller than 1.5 times the thickness of the shell  110 . 
     Also, for the vibration absorbing member  200 , a single plate member having a width similar to a width of the body shell  111 , as illustrated in  FIG. 2 , may be used to cover the shell  110 . In this case, however, it may be difficult to wind the plate member, and thus, the plate member may be divided into at least two parts or portions and wound around the body shell  111  in a lengthwise direction. The vibration absorbing member  200  may be wound around the body shell  111 , as illustrated in  FIG. 3 , or a plurality of vibration absorbing members  200  may be formed to have a snap ring shape and stacked in order to cover the body shell  111 , as illustrated in  FIG. 4 . 
     As illustrated in  FIG. 5 , the layers of the vibration absorbing member  200  may be tightly attached to attenuate noise due to frictional contact, or alternatively, as illustrated in  FIG. 6 , the shell  110  and the vibration absorbing member  200  and the layers of the vibration absorbing member  200  may be spaced apart from one another by fine gaps t 1  and t 2 , respectively, to form spaces  211 . As the spaces  211  form discontinuous points of vibration noise, namely, noise insulating layers, noise of the compressor may be further reduced. 
     The spaces  211  may be naturally generated during a process of winding to form the vibration absorbing member  200 , or as illustrated in  FIG. 7 , the spaces  211  may be forcibly formed by embossing the vibration absorbing member  200 . 
     The spaces  211  each may be formed as an empty space forming a kind of air layer, or as illustrated in  FIG. 8 , the spaces  211  may be filled with a polymer absorbing material  220  formed of a powder material to increase a vibration noise attenuation effect. 
     A frictional damping effect and a noise insulating layer may be required between an inner circumferential surface of an innermost layer of the vibration absorbing member, which may be wound at an innermost portion, and an outer circumferential surface of the shell  110 . Thus, protrusions  110   a , such as angular protrusions, or concave-convex protrusions, for example, may be formed on the outer circumferential surface of the shell  110  in contact with the inner circumferential surface of the innermost layer of the vibration absorbing member  200 , such that shapes of a cross-section of the shell  110  and a cross-section of the vibration absorbing member  200  are different, as illustrated in  FIG. 6 . Accordingly, a space  212  may be formed between the shell  110  and the vibration absorbing member  200  to attenuate vibration noise between the shell  110  and the vibration absorbing member  200 . 
     As described above, in the vibration absorbing member  200  according to this embodiment, both ends thereof in the winding direction may overlap with each other one or more times, namely, one or more layers may overlap with each other, generating frictional damping between the layers of the vibration absorbing member  200 , and thus, even though vibration is generated in the interior of the shell  110  or vibration is transmitted from the exterior of the shell  110 , vibration noise of the compressor may be attenuated, as illustrated in  FIG. 9 . In particular, in the noise insulating layer, noise of a high frequency band may be more effectively attenuated due to fine vibration. 
     Another embodiment of a shell of a reciprocating compressor according to embodiments will be described hereinbelow. 
     As illustrated in  FIG. 10 , body shell  110   b  may be formed to have a cylindrical shape by winding a single plate member several times, so as to serve as a vibration absorbing member itself. In this case, the body shell  110   b  may be sealed by welding an inner circumferential end or an outer circumferential end (the outer circumferential end in the drawing) of the plate member. Also, in this case, the plate member may be tightly attached or may be spaced apart by a predetermined gap to form a space layer or an absorbing material may be interposed between layers. A basic configuration and operational effect thereof are similar to those of the previous embodiment described above. However, in this embodiment, as the body shell  110   b  may be formed by winding a single plate member several times, a number of components may be reduced and an assembling process may be simplified to reduce manufacturing costs and reduce a weight of the compressor, compared with a case in which the shell and the vibration absorbing member are separately manufactured and assembled as in the previous embodiment. 
     Embodiments disclosed herein provide a reciprocating compressor in which vibration transmitted from an exterior of a shell or vibration generated in an interior of the shell may be effectively attenuated. 
     Embodiments disclosed herein provide a reciprocating compressor that may include a shell having an internal space; a reciprocating motor installed in the internal space of the shell and having a mover that reciprocates; a compression mechanism unit coupled to the mover of the reciprocating motor to reciprocate together to compress a refrigerant; and a vibration absorbing member installed to cover at least any one of an inner circumferential surface or an outer circumferential surface of the shell by one or more layers. Accordingly, vibration transmitted through the shell may be attenuated by frictional contact between layers of the vibration absorbing member, as well as by frictional contact between the shell and the vibration absorbing member. 
     The vibration absorbing member may be formed such that two or more layers thereof overlap with each other at an end portion thereof in a direction in which the vibration absorbing member is wound, or a plurality of vibration absorbing members having both ends may be stacked in a circumferential direction layer upon layer. Accordingly, a contact area between the layers of the vibration absorbing members may be increased to further increase a vibration attenuation effect. 
     An overall thickness of the vibration absorbing member may be equal to or greater than a thickness of the shell in order to prevent an excessive increase in the weight and material costs of the overall compressor. The shell and the vibration absorbing member or the layers of the vibration absorbing member may be tightly attached to increase a noise attenuation effect based on frictional contact. 
     The shell and the vibration absorbing member or the layers of the vibration absorbing member may be spaced apart from one another by a predetermined gap to form a space portion or space, whereby an air layer may be formed to further reduce vibration noise. The shell and the vibration absorbing member may have cross-sections in different shapes to form the space portion, or the vibration absorbing member may have an embossed cross-section to form a space portion or space between the vibration absorbing members. A vibration absorbing member formed of a polymer may be inserted into the space portion to further increase a vibration attenuation effect. 
     The shell and the vibration absorbing member may be formed of different materials. The vibration absorbing member may be formed of a material lighter than a material of the shell in order to prevent an excessive increase in weight of the compressor. The vibration absorbing member may be formed of a material having stiffness superior to that of the shell, in order to prevent sagging, for example. 
     The vibration absorbing member may be formed to have a thickness smaller than or equal to that of the shell in order to prevent an excessive increase in a total weight of the compressor. The vibration absorbing member may be coupled by being divided two or more parts or portions in a lengthwise direction of the shell in order to facilitate a coupling operation of the vibration absorbing member. 
     Embodiments disclosed herein further provide a reciprocating compressor that may include a shell; a compressor body installed within the shell to compress a refrigerant; and a support spring configured to elastically support the compressor body with respect to the shell. The shell may include an inner shell and an outer shell, and at least any one of the inner shell or the outer shell may be formed to include a plurality of layers, whereby vibration may be attenuated by interlayer frictional contact of the plurality of layers or an interlayer air layer. The inner shell and the outer shell may be formed of different materials. 
     The inner shell and the outer shell or the layers of the shell formed to include a plurality of layers, among the inner shell and the outer shell, may be tightly attached. Alternatively, air layer may be formed between the inner shell and the outer shell or between the layers of the shell formed to include a plurality of layers, among the inner shell and the outer shell. 
     The shell formed to include a plurality of layers, among the inner shell and the outer shell, may have an irregular cross-section to form an air layer. An absorbing material may be inserted between the inner shell and the outer shell or between the layers of the shell formed to include a plurality of layers, among the inner shell and the outer shell, in order to absorb vibrations. 
     The compression mechanism unit may be configured such that a piston is slidably inserted into a cylinder forming a compression space, and a fluid bearing may be provided in the compression mechanism unit to supply a fluid between the cylinder and the piston to support the piston with respect to the cylinder. Accordingly, there is no need to store separate oil in an internal space of the shell, reducing an oil storage space, and as an oil supply unit is eliminated, the compressor structure may be simplified. Also, a degradation of efficiency of the compressor due to shortage of oil may be prevented in advance. 
     Embodiments disclosed herein further provide a reciprocating compressor that may include a shell having an internal space; a reciprocating motor installed in the internal space of the shell and having a mover that reciprocates; and a compression mechanism unit coupled to the mover of the reciprocating motor to reciprocate together to compress a refrigerant. The shell may be formed by winding a single plate member such that two or more layers overlap with each other. 
     According to the reciprocating compressor according to embodiments, even though vibration may be generated in the shell or vibration may be transmitted to the shell from the outside, the vibration may be attenuated by frictional contact between the shell and the vibration absorbing member or between the layers of the vibration absorbing member. Also, as the noise insulating layer may be formed between the shell and the vibration absorbing member or between the layers of the vibration absorbing member, a magnitude of noise may be reduced as vibration noise passes through the noise insulating layer, whereby vibration noise of the overall compressor, such as noise of a high frequency band, for example, may be attenuated by fine vibration. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be considered broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims. 
     The foregoing embodiments and advantages are merely exemplary and are not to be considered as limiting. The teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.