Patent Publication Number: US-2009232671-A1

Title: Discharging Noise System of a Hermetic Compressor

Description:
TECHNICAL FIELD 
     The present invention relates to a hermetic compressor, and more particularly, to a discharging noise system of a hermetic compressor provided with a connection pipe for connecting discharging noise suppressors. 
     BACKGROUND ART 
       FIG. 1  shows an interior of a conventional compressor. Referring to the figure, the conventional compressor has a hermetic container  1  composed of an upper container  1   t  and a lower container  1   b,  and a frame  2  installed in the hermetic container  1 . A stator  3  is fixed to the frame  2 , and the frame  2  is supported in the hermetic container  1  by means of a spring  2 S. 
     A crank shaft  5  is installed to penetrate a center of the frame  2 . A rotor  4  is integrally installed to the crank shaft  5  to rotate together therewith by means of electromagnetic interaction with the stator  3 . 
     An eccentric pin  5   b  is formed at an upper end of the crank shaft  5  to be eccentric from a rotation center of the crank shaft  5 , and a balancing weight  5   c  is formed at an opposite side to the eccentric pin  5   b.  The crank shaft  5  is installed to penetrate the center of the frame  2 , and the inner circumference of the frame  2  installed through the crank shaft  5  functions as a kind of bearing. 
     In addition, an oil passage  5   a  is formed in the crank shaft  5 . Oil L provided in a bottom of the hermetic container I is guided through the oil passage  5   a  to be transferred to an upper portion of the frame  2  and then scattered. Also, a pumping mechanism  5   d  is installed to a lower end of the crank shaft  5  to pump the oil L and thus transfer it to the oil passage  5   a.    
     Meanwhile, a cylinder block  6  having a compressing chamber  6 ′ provided therein is formed integrally with the frame  2 . Also, a piston  7  connected to the eccentric pin  5   b  of the crank shaft  5  through a connecting rod  8  is installed in the compressing chamber  6 ′. In addition, a valve assembly  9  is installed to a front end of the cylinder block  6  to control a coolant introduced into and discharged from the compressing chamber  6 ′. A head cover  10  is mounted on the valve assembly  9 , and a suction noise suppressor  11  is installed to the head cover  10  to be connected to the valve assembly  9  so that the coolant is transferred to the compressing chamber  6 ′. 
     Reference numeral  12  designates a suction pipe for transferring the coolant into the hermetic container  1 , and reference numeral  13  designates a discharging pipe for discharging the compressed coolant to the outside of the compressor. 
     Meanwhile,  FIG. 2  shows another conventional frame. Referring to the figure, a cylinder block  23  is provided in a frame  20  that has various parts of the compressor. A compressing chamber  24  is formed to be bored through the cylinder block  23 . A piston (not shown) linearly reciprocated by a crank shaft (not shown) is installed in the compressing chamber  24  to compress work fluid. A valve assembly (not shown) is installed together with a head cover (not shown) to the cylinder block  23  that corresponds to a front end of the compressing chamber  24 , wherein a discharging chamber (not shown) is provided between the head cover and the valve assembly such that the work fluid compressed by the piston is temporarily collected in the discharging chamber. 
     First and second discharging noise suppressors  25  and  25 ′ are provided at both sides of the cylinder block  23 . The discharging noise suppressors  25  and  25 ′ are to reduce noise and pulsation of the work fluid compressed in the compressing chamber  24 . A noise chamber (not shown) is formed in each of the discharging noise suppressors  25  and  25 ′ to reduce noise and pulsation while the work fluid stays in the noise chamber for a while. 
     Noise suppressor caps  26  are respectively installed to upper ends of the discharging noise suppressors  25  and  25 ′ to shield the noise chambers. The work fluid compressed in the compressing chamber  24  is firstly transferred to the first discharging noise suppressor  25 , and noise and pulsation are reduced while the work fluid flows from the first discharging noise suppressor  25  to the second noise suppressor  25 ′. To this end, a connection pipe  27  is used to allow the discharging noise suppressors  25  and  25 ′ to communicate with each other through the noise compressor caps  26 . Reference numeral  29  designates a discharging pipe for discharging the work fluid discharged from the second discharging noise suppressor  25 ′ to the outside of the hermetic container. 
     However, the conventional hermetic compressor so configured has the following problems. 
     In general, the piston provided in the compressing chamber  24  linearly reciprocates to compress the work fluid introduced into the compressing chamber  24 . The work fluid compressed by the piston is discharged to the outside of the compressing chamber  24  and then introduced into a discharging chamber communicating with the compressing chamber  24 . The work fluid introduced into the discharging chamber is moved into the first discharging noise suppressor  25 . At this time, the work fluid generates pulsation since it is periodically discharged to the outside of the compressing chamber  24  due to linear reciprocation of the piston. 
     Thus, the pulsation causes vibration of the connection pipe  27  that connects the first and second discharging noise suppressors  25  and  25 ′. The vibration applies repeated stress to connection points of the connection pipe  27 , thereby resulting in fatigue failure. Thus, the work fluid may leak out through the connection points. 
     [Disclosure] 
     [Technical Problem] 
     The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to reduce pulsation generated in a connection pipe. 
     [Technical Solution] 
     According to an aspect of the present invention for achieving the objects, there is provided a discharging noise system of a hermetic compressor, comprising: a first discharging noise suppressor provided in a cylinder block to firstly reduce noise and pulsation of work fluid, the work fluid being compressed in a compressing chamber formed in the cylinder block and discharged therefrom; a second discharging noise suppressor communicating with the first discharging noise suppressor, the work fluid with noise and pulsation reduced by the first discharging noise suppressor being introduced into the second discharging noise suppressor, whereby noise and pulsation of the work fluid is secondarily reduced; a connection pipe for allowing the first and second discharging noise suppressors to communicate with each other to form a channel for allowing the work fluid to move, the connection pipe having a length 1.1 to 1.5 times as long as a shortest straight distance between the discharging noise suppressors; and a discharging pipe provided at the second discharging noise suppressor to form a channel for allowing the work fluid to be discharged to the outside. 
     The connection pipe may include a first inclined portion formed slantingly with respect to a straight distance between the first and second discharging noise suppressors, the first inclined portion having one end connected to the first discharging noise suppressor; and a second inclined portion formed to be slanted reversely with respect to the first inclined portion, the second inclined portion having one end connected to the first inclined portion and the other end connected to the second discharging noise suppressor. 
     [Advantageous Effects] 
     A connection pipe for connecting discharging noise suppressors in the present invention is formed relatively longer than the shortest straight distance between the discharging noise suppressors. As the connection pipe is longer, pulsation is reduced. Thus, operation characteristics of a hermetic compressor are improved. If the operation characteristics of the hermetic compressor are improved, vibration generated from the pulsation is also reduced. Thus, the decreased vibration reduces fatigue failure between the connection pipe and the discharging noise suppressors, thereby improving durability of the hermetic compressor. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view showing an interior of a conventional hermetic compressor. 
         FIG. 2  is a perspective view showing an exterior of a conventional discharging noise system of a hermetic compressor. 
         FIG. 3  is a perspective view showing a preferred embodiment of a discharging noise system of a hermetic compressor according to the present invention. 
         FIGS. 4 to 6  are plan views showing various embodiments of the discharging noise system of a hermetic compressor according to the present invention. 
         FIG. 7  is a graph showing the relationship between pulsation and length of a connection pipe of the discharging noise system of a hermetic compressor according to the present invention. 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS FOR MAJOR PORTIONS SHOWN IN DRAWINGS 
     
         
           30 : Frame 
           35 : Cylinder block 
           37 : Compressing chamber 
           39  and  39 ′: Discharging noise suppressor 
           41 : Noise suppressor cap 
           43 : Connection pipe 
           45 : Discharging pipe 
       
    
     [Best Mode] 
     Hereinafter, preferred embodiments of a discharging noise system of a hermetic compressor according to the present invention will be explained in detail with reference to the accompanying drawings. 
       FIGS. 3 to 7  show various embodiments of a discharging noise system of a hermetic compressor according to the present invention. 
     As shown in the figures, a body  31  of a frame  30  is provided with connection legs  33 , and the connection legs  33  are connected by a motor (not shown) provided in the hermetic container. The body  31  is provided with various parts for a compressor. The body  31  is provided with a cylinder block  35 . The cylinder block  35  is to compress a work fluid, and a compressing chamber  37  is formed to be bored through the cylinder block  35  in a fore and aft direction. 
     The work fluid is introduced into the compressing chamber  37 , and a piston (not shown) is provided in the compressing chamber  37 . The piston serves to compress the work fluid introduced into the compressing chamber  37  while reciprocating in the compressing chamber  37 . 
     A valve assembly (not shown) is installed together with a head cover (not shown) to the cylinder block  35  that corresponds to a front end of the compressing chamber  37 , wherein a discharging chamber (not shown) is provided between the head cover and the valve assembly such that the work fluid compressed by the piston is temporarily collected in the discharging chamber. In addition, the work fluid collected in the discharging chamber is moved to discharging noise suppressors  39  and  39 ′, which will be described later. 
     The first and second discharging noise suppressors  39  and  39 ′ are provided at both sides of the cylinder block  35 . The discharging noise suppressors  39  and  39 ′ are to reduce noise and pulsation of the work fluid compressed in the compressing chamber  37 . A noise chamber (not shown) is formed in each of the discharging noise suppressors  39  and  39 ′. The work fluid compressed in the compressing chamber  37  and temporarily collected in the discharging chamber stays in the noise chamber for a while, so that noise and pulsation is reduced. The work fluid introduced into the first discharging noise suppressor  39  is introduced into the second discharging noise suppressor  39 ′ through a connection pipe  43 , which will be described later. 
     Noise suppressor caps  41  are respectively installed to upper ends of the discharging noise suppressors  39  and  39 ′. The noise suppressor cap  41  serves to isolate the noise chamber provided in each of the discharging noise suppressor  39  and  39 ′ from the outside. The connection pipe  43  is provided for allowing the discharging noise suppressors  39  and  39 ′ to communicate with each other through the noise suppressor caps  41 . 
     The connection pipe  43  allows the discharging noise suppressors  39  and  39 ′ to communicate with each other, and the work fluid introduced into the first discharging noise suppressor  39  is transferred to the second discharging noise suppressor  39 ′ through the connection pipe  43 . 
     A characteristic of the pulsation generated in the connection pipe  43  is well shown in  FIG. 7 . The pulsation generated in the connection pipe  43  is shown on a vertical axis in the unit of mBar, and an operating frequency of the piston that causes pulsation is shown on a horizontal axis. As shown in the figure, it would be understood that the pulsation generated in the connection pipe  43  is smaller at the same operating frequency as the length of the connection pipe  43  is longer. 
     Pulsation is reduced as the length of the connection pipe  43  is longer due to the following reason. In a case where the connection pipe  43  is formed corresponding to the shortest straight distance between the discharging noise suppressors  39  and  39 ′, the vibration generated from the pulsation is directly transferred to the connection points between the connection pipe  43  and the discharging noise suppressors  39  and  39 ′, so that the connection points are weak against fatigue failure. However, in a case where the connection pipe  43  is formed to be bent as shown in  FIGS. 4 to 6  at a predetermined position(s), the vibration generated from the pulsation is offset due to the elasticity of the bent portion of the connection pipe  43 , which is more advantageous against fatigue failure. In addition, as the work fluid discharged from the compressing chamber  37  passes through the long connection pipe  43 , the pulsation is reduced. Thus, as the connection pipe  43  is longer, pulsation is reduced. 
     Thus, it is preferred that the connection pipe  43  is formed relatively longer than the shortest straight distance between the discharging noise suppressors  39  and  39 ′. As shown in  FIGS. 4 to 6 , the connection pipe  43  is preferably bent at least once at a predetermined point, and also preferably formed 1.1 to 1.5 times as long as the shortest straight distance between the discharging noise suppressors  39  and  39 ′. 
     The connection pipe  43  may include linear portions  43   a  and inclined portions  43   b,  as shown in  FIG. 4 . One of the linear portions  43   a  formed horizontally with the straight distance between the discharging noise suppressors  39  and  39 ′ has one end connected to the first discharging noise suppressor  39 , and the other end connected to one end of one of the inclined portions  43   b  formed slantingly with respect to the straight distance between the discharging noise suppressors  39  and  39 ′. The other end of the inclined portion  43   b  is connected to one end of another one of the linear portions  43   a.  The other inclined portion  43   b  formed to be slanted reversely with respect to the inclined portion  43   b  connected to the first discharging noise suppressor  39  has one end connected to the other end of the linear portion  43   a,  and the other end connected to the other one of the linear portions  43   a,  and then the linear portion  43   a  is connected to the second discharging noise suppressor  39 ′. 
     In addition, the connection pipe  43  may include linear portions  43   c  and bent portions  43   d,  as shown in  FIG. 5 . The first discharging noise suppressor  39  is connected to one end of one of the linear portions  43   c  formed vertically with respect to the straight distance between the discharging noise suppressors  39  and  39 ′, and the bent portions  43   d  interconnecting the linear portions  43   c  are connected to the other end of the linear portion  43   c.  The linear portions  43   c  and the bent portions  43   d  are alternately connected to each other and then connected to the second discharging noise suppressor  39 ′. 
     A discharging pipe  45 , through which the work fluid introduced from the first discharging noise suppressor  39  is discharged to the outside, is provided at one side of the second discharging noise suppressor  39 ′. The work fluid moving through the discharging pipe  45  is discharged to the outside of the compressor. 
     Hereinafter, operation of the discharging noise system of a hermetic compressor according to the present invention configured as mentioned above will be explained in detail. 
     The piston reciprocates in the compressing chamber  37  provided in the cylinder block  35  to compress a work fluid. The work fluid compressed by the piston is introduced into the discharging chamber communicating with the compressing chamber  37 , and the work fluid introduced into the discharging chamber is again introduced to the first discharging noise suppressor  39 . The work fluid compressed by the piston is periodically discharged to the outside of the compressing chamber  37  by the linear reciprocation of the piston, so that the flow of the work fluid is periodically intercepted. Such a flow characteristic of the work fluid causes pulsation in the hermetic compressor. 
     The pulsation generated in the cylinder block  35  vibrates the connection pipe  43  that. connects the first and second discharging noise suppressors  39  and  39 ′. This vibration acts as repeated stress between the connection pipe  43  and the discharging noise suppressors  39  and  39 ′, thereby causing fatigue failure. However, as shown in  FIG. 7 , the connection pipe  43  has a length longer than the shortest straight distance between the discharging noise suppressors  39  and  39 ′, so that the pulsation is relatively reduced. 
     The work fluid compressed in the compressing chamber  37  is temporarily collected in the discharging chamber communicating with the compressing chamber  37 , and the work fluid temporarily collected in the discharging chamber is introduced into the first discharging noise suppressor  39 . If the work fluid is introduced into the first discharging noise suppressor  39 , noise and pulsation are reduced due to the noise chamber in the first discharging noise suppressor  39 . The work fluid periodically discharged from the compressing chamber  37  is temporarily collected in the noise chamber having a relatively wide inner space, thereby reducing the noise and pulsation. The work fluid with the noise and pulsation reduced by the first discharging noise suppressor  39  is introduced into the second discharging noise suppressor  39 ′ along the connection pipe  43 . 
     When the work fluid is introduced into the second discharging noise suppressor  39 ′, the noise and pulsation are also reduced by means of the noise chamber provided therein. Thus, if the work fluid passes through the discharging noise suppressors  39  and  39 ′, the noise and pulsation are reduced twice. The work fluid passing through the second discharging noise suppressor  39 ′ is discharged to the outside through the discharging pipe  45 . 
     It will be apparent that those skilled in the art can make various modifications thereto within the scope of the fundamental technical spirit of the present invention. The true scope of the present invention should be interpreted on the basis of the appended claims. 
     INDUSTRIAL APPLICABILITY 
     The present invention is used for reducing noise and vibration of a hermetic compressor.