Patent Publication Number: US-2006002807-A1

Title: Hermetic compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims the benefit of Korean Patent Application No. 2004-51096, filed on Jul. 1, 2004 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a hermetic compressor, and, more particularly, to a hermetic compressor having a discharge muffler capable of attenuating noise generated when a compressed refrigerant is discharged to the outside.  
      2. Description of the Related Art  
      In general, a hermetic compressor is designed to suction a refrigerant into a hermetic casing thereof to compress it, and discharge the compressed refrigerant to the outside. Such a hermetic compressor comprises a compressing unit to compress the refrigerant and a driving unit to drive the compressing unit.  
      The compressing unit is disposed inside the hermetic casing, and includes a cylinder block defining a compression chamber, and a piston reciprocating inside the compression chamber upon receiving power transmitted from the driving unit. A cylinder head is disposed at one side of the cylinder block and is formed with a suction chamber and a discharge chamber, which communicate with the outside.  
      A valve unit is provided between the cylinder block and the cylinder head in order to permit selective communication between the suction chamber and the compression chamber or between the discharge chamber and the compression chamber.  
      In order to attenuate pulsation of the refrigerant being discharged from the discharge chamber, a pair of discharge mufflers are provided at both ends of the cylinder block, respectively. A respective one of the discharge mufflers has a muffler body defined in the cylinder block, and a muffler cover to cover the muffler body. The muffler cover is coupled to the muffler body as a fastening bolt penetrates through the muffler cover and is fastened to the muffler body. A washer is interposed between a head portion of the fastening bolt and the muffler cover in order to increase fastening force of the bolt.  
      However, the typical hermetic compressor has a problem in that it should have several parts, such as the fastening bolt and the washer, for the coupling of the muffler body and the muffler cover, resulting in a complicated manufacturing process and high manufacturing cost of the compressor.  
      Further, the fastening bolt and the washer may generate debris as a result of wear, resulting in a deterioration in the quality of the compressor.  
     SUMMARY OF THE INVENTION  
      The present invention has been made in view of the above mentioned problems, and an aspect of the invention is to provide a hermetic compressor which can eliminate the need for additional parts, such as a fastening bolt and washer, required to couple a muffler body with a muffler cover to assemble a discharge muffler, thereby simplifying the overall manufacturing process and reducing the manufacturing cost of the compressor.  
      In accordance with an aspect, the present invention provides a hermetic compressor comprising a cylinder block defining a compression chamber, a piston reciprocating inside the compression chamber to compress a refrigerant, and a discharge muffler configured to receive the refrigerant compressed in the compression chamber, the discharge muffler including a muffler body defined in the cylinder block and a muffler cover to cover the muffler body, the muffler cover having an integral fixing protrusion to be affixed relative to a bottom surface of the muffler body.  
      The muffler body may have a fixing recess formed at the bottom surface thereof to permit the fixing protrusion of the muffler cover to be fixedly inserted therein.  
      The muffler body may further have an annular raised rim portion extending upward from the bottom surface of the muffler body toward the muffler cover to define the fixing recess.  
      A gasket may be interposed between the muffler cover and the muffler body to ensure sufficient sealing therebewteen.  
      The compressor may further comprise a discharge tube to discharge the refrigerant from the interior of the discharge muffler to the outside, and the discharge tube may be mounted in a fitting bore perforated through the fixing protrusion of the muffler cover.  
      The discharge tube may have a first communication hole at a circumferential position thereof, and the fixing protrusion may have a second communication hole at a circumferential position thereof corresponding to the first communication hole, for the communication between the discharge tube and the interior of the discharge muffler.  
      The muffler cover may further have a pair of partitions extending toward the bottom surface of the muffler body, the partitions being spaced apart from the bottom surface of the muffler body.  
      The partitions may be positioned at opposite sides of the fixing protrusion.  
      Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other aspects and advantages of the invention will become apparent and more easily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
       FIG. 1  is a side sectional view of a hermetic compressor in accordance with the present invention;  
       FIG. 2  is a plan view of the hermetic compressor shown in  FIG. 1 ;  
       FIG. 3  is a sectional view of a discharge muffler provided in the hermetic compressor in accordance with a first embodiment of the present invention;  
       FIG. 4  is a sectional view of a discharge muffler provided in the hermetic compressor in accordance with a second embodiment of the present invention;  
       FIG. 5  is a sectional view of a discharge muffler provided in the hermetic compressor in accordance with a third embodiment of the present invention; and  
       FIG. 6  is a sectional view of a discharge muffler provided in the hermetic compressor in accordance with a fourth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the embodiment of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.  
       FIG. 1  is a side sectional view of a hermetic compressor in accordance with the present invention. Referring to  FIG. 1 , the hermetic compressor of the present invention comprises a compressing unit  20  disposed inside a hermetic casing  10  to compress a refrigerant, and a driving unit  30  to generate power required to drive the compressing unit  20 .  
      The compressing unit  20  includes a cylinder block  21  internally defining a compression chamber  21   a , and a piston  22  reciprocating inside the compression chamber  21   a  so as to suction, compress and discharge the refrigerant. A cylinder head  23  is disposed at one end of the cylinder block  21  to face each other. The cylinder head  23  internally defines a suction chamber  23   a  and a discharge chamber  23   b . A valve unit  24  is interposed between the cylinder block  21  and the cylinder head  23  so as to selectively communicate the suction chamber  23   a  or the discharge chamber  23   b  with the compression chamber  21   a.    
      The driving unit  30  operates to reciprocate the piston  22 , thereby permitting the refrigerant to be compressed inside the compressing unit  20 . The driving unit  30  includes a stator  31  fixedly disposed inside the hermetic casing  10 , and a rotor  32  inwardly spaced apart from the stator  31  to electromagnetically interact with the stator  31 . A rotating shaft  33  is coupled in the center of the rotor  32  to rotate simultaneously with the rotor  32 . An end of the rotating shaft  33  is coupled to one end of a connecting rod  34  to permit rotation of the connecting rod  34 . The rotation of the connecting rod  34  causes the other end thereof to linearly reciprocate to thereby move the piston  22  forward or backward.  
       FIGS. 2 and 3  are a plan view and a sectional view illustrating a discharge muffler provided in the hermetic compressor in accordance with a first embodiment of the present invention. Referring to  FIGS. 2 and 3 , the discharge muffler  40  according to the first embodiment of the present invention is provided at at least one of both ends of the cylinder block  21  and is adapted to attenuate noise of the refrigerant being discharged out of the compressor. The discharge muffler  40  has a dented muffler body  50  defined in the cylinder block  21  and a muffler cover  60  to cover the muffler body  50 .  
      The muffler body  50  has an inlet  51  to permit introduction of the refrigerant into the discharge muffler  40 . The inlet  51  communicates with a guide channel  25  which is perforated through the cylinder block  21  to guide the refrigerant from the compression chamber  21   a  into the discharge muffler  40 .  
      The muffler body  50  further has an outlet  52  positioned opposite to the inlet  51  to permit discharge of the refrigerant from the discharge muffler  40 . A seating groove  53  is defined at an upper end of the muffler body  50  for the seating of the muffler cover  60 .  
      When the muffler cover  60  covers the muffler body  50 , it defines a space to attenuate pulsation of the refrigerant. In the present embodiment, the muffler cover  60  has a center fixing protrusion  61  extending from a lower surface thereof toward a bottom surface of the muffler body  60 . The fixing protrusion  61  is affixed relative to the bottom surface of the muffler body  50  to securely couple the muffler cover  60  with the muffler body  50 . In this case, the bottom surface of the muffler body  50  is formed with a fixing recess  54  to permit an end region of the fixing protrusion  61  to be inserted and fixed therein. In order to ensure sufficient fitting of the fixing protrusion  61  in the fixing recess  54 , an annular raised rim portion  55  is also formed at the bottom surface of the muffler body  50  to define the fixing recess  54 . The annular raised rim portion  55  protrudes upward by a distance suitable to provide the fixing recess  54  with a sufficient depth.  
      In order to improve sealing efficiency between the coupled muffler cover  60  and muffler body  50 , a gasket  70  is interposed between the muffler cover  60  and the muffler body  50 .  
      Meanwhile, the fixing protrusion  61  may be forcibly press-fitted into the fixing recess  54 , or may be screwed into the fixing recess  54  as is shown in  FIG. 4 . In the latter case, the fixing protrusion  61  is provided at an outer circumference thereof with a first screw portion  61   a , while the fixing recess  54  is provided at an inner circumference thereof with a second screw portion  54   a  corresponding to the first screw portion  61   a.    
      Referring to  FIG. 5 , a discharge tube  80  is mounted in the muffler cover  60  in order to permit the refrigerant, which has been reduced in pulsation thereof within the discharge muffler  40 , to be discharged out of the compressor via the discharge tube  80 . In this case, the discharge tube  80  is fitted in an elongated fitting bore  62  which extends, starting from an upper end of the muffler cover  60 , through the fixing protrusion  61 . For the communication between the discharge tube  80  and the interior of the discharge muffler  40 , the discharge tube  80  has a first communication hole  81  at a circumferential position thereof, and the fixing protrusion  61  has a second communication hole  63  at a circumferential position thereof corresponding to the first communication hole  81 .  
      Referring to  FIG. 6 , the muffler cover  60  may further have a pair of partitions  64  extending downward from the lower surface of the muffler cover  60  toward the bottom surface of the muffler body  50 . The partitions  64  are positioned at opposite sides of the fixing protrusion  61 , and are spaced apart at their distal ends from the bottom surface of the muffler body  50 . Such an arrangement permits the refrigerant to be compressed and diffused while passing through a space defined between the distal ends of the partitions  64  and the bottom surface of the muffler body  50 , thereby effectively attenuating refrigerant pulsation.  
      Now, the general operation of the hermetic compressor according to the present invention will be explained.  
      When power is applied to the driving unit  30 , the rotor  32  rotates simultaneously with the rotating shaft  33 . The rotation of the rotating shaft  33  causes the piston  22  to reciprocate inside the compression chamber  21   a  to thereby allow the refrigerant to be suctioned from the suction chamber  23   a  of the cylinder head  23  into the compression chamber  21   a  and be compressed in the compression chamber  21   a . After that, the compressed refrigerant is discharged into the discharge chamber  23   b  of the cylinder head  23  via the valve unit  24  according to reciprocation of the piston  22 .  
      In succession, the refrigerant discharged into the discharge chamber  23   b  is introduced into the inlet  51  of the muffler body  50  via the guide channel  25  defined in the cylinder block  21 . Thereby, within the discharge muffler  40 , which is formed by securely coupling the muffler body  50  with the muffler cover  60  in the present invention, the refrigerant can undergo attenuation in the pulsation thereof and is finally discharged out of the compressor.  
      As is apparent from the above description, a hermetic compressor according to the present invention comprises a discharge muffler in which a muffler cover is securely coupled to a muffler body via a fixing protrusion integrally formed at the muffler cover. With such a configuration, there is no need to provide additional parts, such as bolts and washers, required to couple the muffler cover with the muffler body. This has the effect of simplifying the overall manufacturing process and reducing manufacturing costs of the compressor.  
      Although an embodiment of the present invention has been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.