Patent Publication Number: US-2005129548-A1

Title: Suction valve and reciprocating compressor having the same

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a reciprocating compressor, and more particularly, to a suction valve capable of enhancing a compressing efficiency by improving a structure thereof for opening and closing a suction channel through which a refrigerant is sucked into a cylinder, and a reciprocating compressor having the suction valve.  
      2. Description of the Conventional Art  
      A compressor is for compressing a refrigerant by constituting a part of a refrigerating cycle of a device such as a refrigerator, an air conditioner, etc. Generally, the compressor includes: a motor part installed inside a hermetic container for generating a rotational driving force; and a compression part for sucking and compressing a refrigerant by receiving the rotational driving force of the motor part.  
      The compression part is composed of: a cylinder for sucking a fluid; a piston reciprocatingly inserted into the cylinder; a suction valve and a discharge valve for alternately opening and closing the inner space of the cylinder according to the linear reciprocation of the piston; etc.  
      In a reciprocating compressor, the compression part transmits a rotational driving force generated from the motor part to the piston thereby to linearly reciprocate the piston. Accordingly as the piston linearly reciprocates, the suction valve and the discharge valve are alternately opened and closed thereby to suck a refrigerant into the cylinder and discharge the refrigerant, which is performed repeatedly and consecutively thus to compress the refrigerant.  
       FIG. 1  is a longitudinal section view showing a construction of a general reciprocating compressor. As shown, a supporting spring  110  is installed in a hermetic container  100  composed of a lower hermetic container  101  and an upper hermetic container  102 . A motor part  120  and a compression part  130  are supported by the supporting spring  110 .  
      The motor part  120  is composed of: a stator  122   a  mounted at a frame  121 ; a rotor  122   b  inserted into the stator  122   a  thus to perform an electrical interaction with the stator  122   a ; and a rotational shaft  123  inserted into the center of the frame  121  and fixedly coupled to the rotor  122   b.    
      The compression part  130  is positioned at the upper portion of the rotational shaft  123 , and an eccentric portion  131  eccentric from the center of the rotational shaft  123  is integrally provided at the compression part  130 . One end of a connection rod  132  is connected to the eccentric portion  131 , and another end thereof is connected to one end of a piston  133 . The piston  133  is inserted into a cylinder  134 , and a head  135  having a suction channel and a discharge channel for sucking and discharging a refrigerant is provided at the front side of the cylinder  134 . A suction valve seat  136  having a suction valve for opening and closing the suction channel is installed between the cylinder  134  and the head  135 . A discharge valve (not shown) for opening and closing the discharge channel, and a head cover  137  separately provided with a suction muffler and a discharge muffler respectively connected to the suction channel and the discharge channel are formed at the front side of the head  135 .  
      In the reciprocating compressor, when a power source is supplied to the motor part  120 , a repulsive force and an attractive force are generated by the electrical interaction between the stator  122   a  and the rotor  122   b  of a motor  122 . According to this, the rotor  122   b  is rotated thus to rotate the rotational shaft  123 .  
      When the rotational shaft  123  is rotated, the eccentric portion  131  formed at the upper portion of the rotational shaft  123  is eccentrically rotated centering around the rotational shaft  123 . The connection rod  132  transmits the eccentric rotation motion of the eccentric portion  131  to the piston  133 , so that the piston  133  is linearly reciprocated in the cylinder  134 .  
      Accordingly as the piston is linearly reciprocated in the cylinder, the suction valve and the discharge valve are alternately operated thus to suck, compress, and discharge gas.  
      In the reciprocating compressor, the conventional suction valve for opening and closing the suction channel by a pressure difference inside the cylinder, is formed as a cut portion  200  cut as a predetermined shape at the suction valve seat  136  constituted with a thin plate having a predetermined area as shown in  FIGS. 2 and 3 .  
      The suction valve is composed of: an open/close portion  212  formed as a circular shape for opening and closing the suction channel; and an elastic portion  211  extended from the open/close portion as a straight line having a predetermined length for elastically supporting the open/close portion  212 . The open/close portion and the elastic portion have a cantilever shape.  
      Operation of the suction valve will be explained in more detail as follows.  
      When the piston  133  reciprocated in the cylinder  134  is moved from an upper dead point H to a lower dead point L by receiving a driving force of the motor part, the elastic portion  211  of the suction valve is bent by a pressure difference between outside and inside of the cylinder thereby to open the suction channel  220 . According to this, a refrigerant is sucked into the cylinder  134  through the suction channel of the head  135 . When the piston  133  is moved from the lower dead point L to the upper dead point H, the open/close portion  212  gets straightened by the pressure difference between inside and outside of the cylinder  134  and by a restoration force of the elastic force thereby to block the suction channel  220 . At the same time, the refrigerant inside the cylinder  134  is compressed, and a discharge valve (not shown) is moved thus to open a discharge channel (not shown) when the pressure of the refrigerant exceeds a preset pressure. According to this, the compressed refrigerant is discharged to outside of the cylinder through the discharge channel, and the discharged refrigerant is discharged to outside of the compressor through a muffler coupled to the cylinder.  
      However, in the process that the elastic portion  211  of the suction valve  210  is bent by the pressure difference between inside and outside of the cylinder  134  and the open/close portion  212  opens the suction channel  220  thus to suck the refrigerant into the cylinder  134 , the open/close portion  212  opens/closes the suction channel  220  as an inclined state since the elastic portion  211  having a predetermined width is formed as a straight line. Additionally, the elastic portion  211  for elastically supporting the open/close portion  212  disturbs the refrigerant flow thus to cause a flow resistance of the refrigerant sucked into the cylinder  134  through the suction channel  220 . According to this, a suction amount of the refrigerant sucked into the cylinder  134  through the suction channel  220  is relatively decreased thus to degrade the compression function, to cause noise due to the flow resistance, and thereby to lower the reliability.  
     SUMMARY OF THE INVENTION  
      Therefore, an object of the present invention is to provide a suction valve capable of maximizing a refrigerant suction amount and minimizing noise by minimizing a suction flow resistance of a refrigerant sucked into a cylinder at the time of opening a suction channel by a pressure difference between inside and outside of the cylinder, and a reciprocating compressor having the suction valve.  
      To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a reciprocating compressor comprising: a motor part mounted inside a hermetic container for generating a rotational driving force; and a compression part for sucking a refrigerant into a cylinder and discharging the refrigerant through a suction channel and a discharge channel of a head accordingly as a piston is linearly reciprocated in the cylinder by the rotational driving force of the motor part, in the reciprocating compressor, a suction valve seat is included, the suction valve seat composed of: an open/close portion fixed between the cylinder and the head of the compression part and opposite to the suction channel for opening and closing the suction channel; and an elastic portion formed as a curved line at the periphery of the open/close portion for elastically supporting the open/close portion.  
      To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided a suction valve comprising: an open/close portion formed as a thin plate of a predetermined shape for opening and closing a suction channel through which a refrigerant is sucked into a cylinder; and an elastic portion extended from the open/close portion as a curved line form to cover the open/close portion for elastically supporting the open/close portion.  
      The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.  
      In the drawings:  
       FIG. 1  is a longitudinal section view showing a construction of a reciprocating compressor in accordance with the conventional art;  
       FIG. 2  is a plane view showing a suction valve seat in accordance with the conventional art;  
       FIG. 3  is a longitudinal section view showing a state that a refrigerant is sucked by opening a suction valve in accordance with the conventional art;  
       FIG. 4  is a plane view showing a suction valve seat according to the present invention;  
       FIG. 5  is a longitudinal section view showing a state that a refrigerant is sucked by opening a suction valve according to the present invention; and  
       FIG. 6  is a graph showing a variation of an inner pressure of a cylinder and an outlet pressure of a suction muffler at the time of sucking and discharging a refrigerant in the conventional reciprocating compressor having a suction valve and a reciprocating compressor having a suction valve according to the present invention.  
       FIG. 7  is a graph showing a pressure loss of a valve in the conventional reciprocating compressor having a suction valve and a reciprocating compressor having a suction valve according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
      Hereinafter, preferred embodiments of a reciprocating compressor according to the present invention will be explained with reference to the attached drawings.  
      Even if a plurality of preferred embodiments of a suction valve of a reciprocating compressor according to the present invention may exist, the most preferred embodiment will be explained hereinafter.  
      The reciprocating compressor according to the present invention comprises: a motor part for generating a rotational driving force; and a compression part for sucking and discharging a refrigerant by the rotational driving force of the motor part. The structure of the reciprocating compressor is equal to that of the conventional reciprocating compressor except the compression part.  
      The compression part includes: a cylinder; a piston mounted in the cylinder and linearly reciprocated by the rotational driving force, for sucking a refrigerant into the cylinder and discharging; a head installed at the front side of the cylinder and having a suction channel and a discharge channel for sucking a refrigerant and discharging; a suction valve seat provided between the cylinder and the head; an open/close portion opposite to the suction channel at the suction valve seat for opening and closing the suction channel; and an elastic portion formed at the periphery of the open/close portion as a curved line for elastically supporting the open/close portion.  
       FIG. 4  is a plane view showing a suction valve seat according to one embodiment of the present invention, and  FIG. 5  is a longitudinal section view showing a state that a refrigerant is sucked by opening a suction valve according to the present invention. A suction valve seat  400  is provided with a suction valve  440 . The suction valve  440  is composed of: an open/close portion  441  opposite to a suction channel  411  formed ata head  410  for sucking a refrigerant of a suction muffler  420  into a cylinder  430 ; and an elastic portion  442  formed by cutting the periphery of the open/close portion  441  as a spiral shape.  
      As another embodiment of the suction valve  440 , the elastic portion  442  cut as a double-spiral shape that the periphery of the open/close portion  441  is symmetrical in the diagonal direction, and for elastically supporting the open/close portion  441  may be formed.  
      As still another embodiment of the suction valve  440 , an inner part except the open/close portion  441  may be cut. In that case, the material of the suction valve seat  400  can be reduced and the suction valve seat  400  can be fabricated with a light weight. It is preferable to cut a part that a stress is not concentrated in the suction valve seat  400 .  
      The suction valve seat  400  is preferably abrasion-resistance processed in order to reduce an abrasion between the end of the open/close portion  441  and the head  410 . The end of the open/close portion  441  collides with the head the most severely, and only the end of the open/close portion  441  can be selectively abrasion-resistance processed thereby to prevent the abrasion.  
      Operation of the suction valve of the reciprocating compressor according to the present invention will be explained as follows.  
      When the piston  433  reciprocated in the cylinder  430  is moved from an upper dead point H to a lower dead point L by receiving a driving force of the motor part, the elastic portion  442  of the suction valve is bent by a pressure difference between outside and inside of the cylinder. According to this, the open/close portion  441  connected to the elastic portion  442  opens the suction channel  411 , and thereby a refrigerant is sucked into the cylinder  430  through the suction channel  411  of the head  410 .  
      In the process that the elastic portion  442  of the suction valve  440  is bent by the pressure difference between inside and outside of the cylinder  430  and the open/close portion  441  opens the suction channel  411  thus to suck the refrigerant into the cylinder  430 , the elastic portion  442  having a predetermined width and formed as a curved line is entirely and simultaneously deformed when compared the case that the elastic portion  442  is formed as a straight line. According to this, the entire open/close portion  441  simultaneously opens the suction channel  411 , and thereby an effective flow area of the suction channel  411  becomes wide. Therefore, a refrigerant sucked through the suction channel  411  receives less flow resistance and a refrigerant suction amount is relatively increased, thereby enhancing the compression function and reducing noise due to the flow resistance.  
      The conventional suction valve of  FIG. 2  and the suction valve according to one embodiment of the present invention of  FIG. 4  were respectively applied to a reciprocating compressor thus to obtain the following result shown in the table 1, in which the heat capacity denotes a refrigerating capacity, the work input denotes a consumption power, the EER denotes an energy efficiency ratio, the Re-Exp denotes a loss generated when a refrigerant is re-expanded, the undershoot denotes a loss generated when a pressure is lowered below a reference pressure in the process of sucking a refrigerant, the suction heat denotes a loss generated when a temperature is lowered below a reference temperature in the process of sucking a refrigerant, the Comp denotes a loss generated in the process of compressing a refrigerant, the overshoot denotes a loss generated when a pressure is increased above a reference pressure in the process of discharging a refrigerant; the Re-Exp denotes an efficiency generated when a refrigerant is re-expanded, the undershoot denotes an efficiency generated when a pressure is lowered below a reference pressure in the process of sucking a refrigerant, the suction heat denotes an efficiency generated when a temperature is lowered below a reference temperature in the process of sucking a refrigerant, the Comp denotes an efficiency generated in the process of compressing a refrigerant, the overshoot denotes an efficiency generated when a pressure is increased above a reference pressure in the process of discharging a refrigerant, and the over-all denotes the entire compression efficiency.  
                                   TABLE 1                                      Heat   Work       Loss (W)                                                     Capacity   Input               Suction                   (Kcal/h)   (W)   EER   Re-Exp   Undershoot   heat   Comp   Overshoot               Conventional   232.82   162.2   5.699   −14.702   4.7694   39.3203   −7.508   7.0705       suction valve       Suction valve   236.22   163.4   5.739   −14.253   4.1836   38.3781   −9.044   7.5446       of the present       invention                         Efficiency                                             Suction                   Re-Exp   Undershoot   heat   Comp   Overshoot   Over-all               0.9362   0.9632   0.8625   1.0116   0.9453   0.7447       0.9365   0.9677   0.8718   1.0522   0.9411   0.7839                  
 
      As shown in the above table 1, in the reciprocating compressor having the suction valve according to the present invention, a loss generated when a pressure is increased above a reference pressure (overshoot) in the process of discharging a refrigerant was more than that of the reciprocating compressor having the conventional suction valve, and an efficiency generated when a pressure is increased above a reference pressure (overshoot) in the process of discharging a refrigerant was less than that of the reciprocating compressor having the conventional suction valve. However, in the reciprocating compressor having the suction valve according to the present invention, the energy efficiency (EER) was increased by approximately 0.04 and the entire compression efficiency (Over-all) was increased by approximately 0.04%, that is, the loss was less and the efficiency was increased entirely.  
       FIG. 6  is a graph showing a variation of an inner pressure of a cylinder and an outlet pressure of a suction muffler at the time of sucking and discharging a refrigerant in the conventional reciprocating compressor having a suction valve and a reciprocating compressor having a suction valve according to the present invention, and  FIG. 7  shows a loss of the suction valve obtained by subtracting the inner pressure of the cylinder from the outlet pressure of the suction muffler.  
      Referring to  FIG. 6 , the outlet pressure of the suction muffler will be explained. When a rotation phase angle of the rotational shaft for sucking a refrigerant into the cylinder is in a range of 220˜315°, a pulsation component was greatly reduced in the present invention than in the conventional art and thereby noise generated by opening and closing the suction valve was greatly reduced.  
      As shown in  FIG. 7 , the loss of the suction valve is increased in the present invention than in the conventional art when the rotation phase angle of the rotational shaft is approximately 235°. However, the loss of the suction valve is greatly decreased in the present invention than in the conventional art at another rotation phase angle except the 2350.  
      As aforementioned, since the effective flow area of the suction valve becomes wide and the flow resistance due to the refrigerant suction becomes less, the compression efficiency of the refrigerant is entirely increased.  
      In summary, in the reciprocating compressor according to the present invention, the suction valve for sucking a refrigerant into the cylinder is composed of: the open/close portion for opening and closing the suction channel; and the elastic portion formed at the periphery of the open/close portion as a curved line for elastically supporting the open/close portion. According to this, noise generated form the compressor is reduced and the effective flow area becomes wide at the time of sucking the refrigerant thus to increase a suction amount of the refrigerant, thereby increasing a suction efficiency and enhancing the compression efficiency of the compressor.  
      As the present invention may be embodied in several forms without departing from the spirit or essential 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 construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.