Patent Publication Number: US-2005129534-A1

Title: Hermetic compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims the benefit of Korean Patent Application No. 2003-91119, filed Dec. 15, 2003 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, in general, to hermetic compressors and, more particularly, to a suction muffler of a hermetic compressor, which draws a gas refrigerant of a low pressure passing through an inlet pipe into a compression chamber of a cylinder block.  
      2. Description of the Related Art  
      Generally, hermetic compressors are widely used in refrigeration systems, such as a refrigerator, to compress a refrigerant. A conventional hermetic compressor includes a hermetic casing to define a hermetic space, with a compressing unit to compress a refrigerant and a drive unit to drive the compressing unit being installed in the hermetic casing.  
      The compressing unit includes a cylinder block which defines a compression chamber to compress the refrigerant. A cylinder head is mounted to an end of the cylinder block, and has both a suction chamber to guide the refrigerant into the compression chamber, and an exhaust chamber to guide the compressed refrigerant from the compression chamber to an outside of the hermetic casing. Further, a piston is installed in the compression chamber.  
      The drive unit includes a stator which generates an electromagnetic field, when an electric power is applied to the stator. A rotor is rotated by the electromagnetic field generated along the stator, and rotates a rotating shaft. Due to a rotating motion of the rotor, the piston reciprocates in the compression chamber, thus compressing the refrigerant.  
      Further, an inlet pipe is installed at a predetermined portion of the hermetic casing to draw the refrigerant from the outside of the hermetic casing. A suction muffler is provided at a predetermined portion of the hermetic casing to communicate with the inlet pipe.  
      The suction muffler functions to reduce noises produced when the refrigerant is compressed by the compressing unit, in addition to guiding the refrigerant into the suction chamber of the cylinder head.  
      However, the conventional hermetic compressor is constructed so that the noises are deadened in the resonance chamber provided in the suction muffler. Thus, the conventional hermetic compressor has a problem in that the noises are not completely absorbed in the resonance chamber, but some noises are released to an outside of the compressor through the inlet pipe. Thereby, the flowing direction of the refrigerant is opposite to the releasing direction of the noises in the inlet pipe, thus causing resonance between refrigerant flowing frequency and noise frequency, therefore increasing noises and vibrations of the compressor.  
     SUMMARY OF THE INVENTION  
      Accordingly, it is an aspect of the present invention to provide a hermetic compressor which has an improved structure of a suction muffler, thus efficiently reducing noise and vibrations.  
      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.  
      The above and/or other aspects are achieved by a hermetic compressor, including a hermetic casing, a compressing unit provided in the hermetic casing to compress a refrigerant, an inlet pipe to guide the refrigerant into the hermetic casing, and a suction muffler to draw the refrigerant through the inlet pipe and to discharge the refrigerant to the compressing unit. The suction muffler includes a muffler casing, an inlet part, and a refrigerant guide pipe. The muffler casing defines a resonance chamber therein. The inlet part is provided at a predetermined portion of the muffler casing, and has an inlet port to allow the refrigerant to be drawn into the muffler casing, with the inlet port being provided to be spaced apart from the inlet pipe. The refrigerant guide pipe extends from an interior of the resonance chamber to communicate with the compressing unit, with an expanding part having an enlarged diameter and being provided at an inlet of the refrigerant guide pipe.  
      According to an aspect of the invention, the expanding part may be provided to be tapered in a flowing direction of the refrigerant which is drawn into the muffler casing.  
      In another aspect of this embodiment, the inlet port may have a shape of a semi-flare pipe which is tapered in a flowing direction of the refrigerant which is drawn into the muffler casing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:  
       FIG. 1  is a sectional view of a hermetic compressor, according to an embodiment of the present invention;  
       FIG. 2  is a sectional view of a suction muffler of the hermetic compressor of  FIG. 1 ; and  
       FIG. 3  is a perspective view of a refrigerant guide pipe of the suction muffler of  FIG. 2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below in order to explain the present invention by referring to the figures.  
       FIG. 1  is a sectional view of a hermetic compressor, according to an embodiment of the present invention. Referring to  FIG. 1 , the hermetic compressor includes a hermetic casing  10 , with a compressing unit  20  and a drive unit  30  being installed in the hermetic casing  10 . The compressing unit  20  compresses a refrigerant, and the drive unit  30  generates a power to drive the compressing unit  20 .  
      The compressing unit  20  includes a cylinder block  21  to define a compression chamber  21   a  therein. A piston  22  is received in the compression chamber  21   a , and rectilinearly reciprocates in the compression chamber  21   a  to draw, compress, and discharge the refrigerant. A cylinder head  23  is mounted to an end of the cylinder block  21 , with a suction chamber  23   a  and an exhaust chamber  23   b  being defined in the cylinder head  23 . Further, a valve plate  24  is interposed between the cylinder block  21  and the cylinder head  23 , and includes an inlet valve  24   a  to allow the refrigerant to be drawn into the compression chamber  21   a , and an outlet valve  24   b  to allow the compressed refrigerant to be discharged from the compression chamber  21   a.    
      The drive unit  30  is provided to reciprocate the piston  22 , thus compressing the refrigerant in the compressing unit  20 . The drive unit  30  includes a stator  31  which is installed in the hermetic casing  10 , and a rotor  32  which is set in the stator  31  to be spaced apart from the stator  31  and is rotated by an electromagnetic field generated along the stator  31  when an electric power is applied to the stator  31 . Further, a rotating shaft  33  is provided at a center of the rotor  32  to rotate along with the rotor  32 . An eccentric part  34  which eccentrically rotates and a connecting rod  35  are provided under the rotating shaft  33 . The connecting rod  35  is connected at a first end thereof to the eccentric part  34  and at a second end thereof to the piston  22 , thus converting the rotating motion of the eccentric part  34  into the rectilinear reciprocating motion of the piston  22 .  
      Further, a suction muffler  50  is provided on a side of the cylinder head  23  to reduce noises produced by compressing the refrigerant in the compression chamber  21   a . The suction muffler  50  of the hermetic compressor according to the present invention will be described in the following in detail with reference to  FIG. 2 .  
      As shown in  FIG. 2 , the suction muffler  50  includes a muffler casing  51 , an inlet part  53 , and an outlet port  55 . The muffler casing  51  defines a resonance chamber  52 . The inlet part  53  is provided at a predetermined position of a lower portion of the muffler casing  51 , and has an inlet port  54  to allow the refrigerant to be drawn into the muffler casing  51 . The outlet port  55  is provided on a bottom of the muffler casing  51  to be opened toward the cylinder head  23 .  
      The inlet part  53  has a shape of a semi-flare pipe which is gradually tapered in a flowing direction of the refrigerant which is drawn from the inlet port  54  into the muffler casing  51 . The inlet port  54  is provided to be spaced apart, by a predetermined distance, from an end of the inlet pipe  40  which penetrates the hermetic casing  10  to draw the refrigerant into the hermetic casing  10 .  
      Of the refrigerant passing through the inlet pipe  40 , a gas refrigerant represented by fine solid arrows flows through the inlet part  53  into the resonance chamber  52 . Meanwhile, a liquid refrigerant represented by thick solid arrows collides against an inclined inner wall of the inlet part  53 , and falls to a bottom of the hermetic casing  10  due to gravity. Thus, the liquid refrigerant is not fed through the inlet part  53  to the muffler casing  51 . Further, such an inlet part  53  allows noises produced in the compressor to be efficiently reduced. The operational effects of the suction muffler  50  having the inlet part  53  constructed as described above will be described hereinafter in detail.  
      According to the present invention, the suction muffler  50  further includes a refrigerant guide pipe  56  to guide the refrigerant from the resonance chamber  52  to the cylinder head  23 .  
      The refrigerant guide pipe  56  extends from an interior of the resonance chamber  52  to the outlet port  55 . In this case, an end of the refrigerant guide pipe  56  is connected to the cylinder head  23 .  
      As shown in  FIG. 3 , the refrigerant guide pipe  56  has, at an inlet thereof through which the refrigerant is drawn, an expanding part  57 . The expanding part  57  has an enlarged diameter, and is provided to be gradually tapered in a flowing direction of the refrigerant which is drawn into the muffler casing  51 .  
      The operation and operational effects of the hermetic compressor constructed as described above will be described in the following.  
      When an electric power is applied to the drive unit  30 , the rotating shaft  33  is rotated along with the rotor  32 . By the rotation of the rotating shaft  33 , the eccentric part  34  is eccentrically rotated. Further, when the piston  22  reciprocates in the compression chamber  21   a  by the rotating motion of the eccentric part  34 , the refrigerant sequentially passes through the suction muffler  50  and the suction chamber  23   a  of the cylinder head  23 . Subsequently, the refrigerant is fed into the compression chamber  21   a  to be compressed. The compressed refrigerant is discharged to the exhaust chamber  23   b  of the cylinder head  23 .  
      At this time, the noises produced by compressing the refrigerant in the compression chamber  21   a  are sent from the suction chamber  23   a  of the cylinder head  23  to the suction muffler  50 , as shown by dotted lines of  FIG. 2 . The noises are sent through the refrigerant guide pipe  56  of the suction muffler  50  to the interior of the resonance chamber  52 .  
      Further, the noises are diffused into the resonance chamber  52  via the expanding part  57  of the refrigerant guide pipe  56 , so that the noises are primarily reduced. Remaining noises are diffused into the compressor through the inlet part  53  having the shape of the semi-flare pipe, so that the noises are secondarily reduced.  
      In a brief description, the suction muffler  50  according to the present invention is constructed to allow the noises to be doubly diffused, thus efficiently reducing the noises.  
      Further, the inlet port  54  is spaced apart from the inlet pipe  40 , so that the noises passing through the inlet port  54  are not sent to an interior of the inlet pipe  40 , but is diffused into the compressor, thus preventing the noise and vibrations from being generated by the resonance between a flowing frequency of the refrigerant and a noise frequency in the inlet pipe  40 .  
      As is apparent from the above description, the present invention provides a hermetic compressor, which is constructed so that a suction muffler includes an expanding part and an inlet part having a shape of a semi-flare pipe, thus efficiently reducing noises produced in a compressing unit, therefore allowing the compressor to be stably operated.  
      Further, in the hermetic compressor of the present invention, an inlet port of the suction muffler is spaced apart from an inlet pipe, thus preventing noises passing through the inlet port from resonating in the inlet pipe, therefore increasing reliability 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 these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.