Patent Publication Number: US-6659732-B2

Title: Supercharging device of hermetic compressor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a hermetic compressor, and more particularly to a supercharging device of the hermetic compressor capable of supplying a great deal of refrigerant into a cylinder. 
     2. Description of the Related Art 
     Generally, a hermetic compressor is widely used for compressing refrigerant in a freezing apparatus such as a refrigerator. 
     As shown in FIG. 1, a reciprocating compressor as one of the hermetic compressors comprises an electric driving unit and a compressing unit. The compressing unit is used for compressing the refrigerant by being driven by the electric driving unit in a sealed casing  1 . 
     The electric driving unit comprises a stator  10 , a rotor  20  for being rotated by an electromagnetic interaction with the stator  10 , and a crankshaft  21  installed at a center of the rotor  20 . 
     The compressing unit comprises a cylinder block  40 , a connecting rod  31  eccentrically connected with a lower part of the crankshaft  21 , a piston  32  that linearly reciprocates in a cylinder  41  formed in the cylinder block  40  by being connected with a front end of the connecting rod  31 , and a cylinder head  43  for sealing the cylinder  41 . A valve assembly  42  is disposed between the cylinder head  43  and the cylinder  41 . The valve assembly  42  includes a suction valve (not shown) and a discharge valve (not shown) for controlling a flow of the refrigerant between the cylinder head  43  and the cylinder  41 . 
     A suction muffler  50 , connected with one side of the cylinder head  43 , is disposed at an upper part of the cylinder head  43 . A refrigerant suction pipe  51 , for drawing in the refrigerant from an evaporator (not shown) of the freezing apparatus, is connected with the suction muffler  50 . On the other hand, a discharge muffler  60 , connected with the other side of the cylinder head  43 , is disposed at a lower side of the cylinder block  40 . 
     For a compressor having the above construction, since the piston  32  reciprocates between an upper dead point and a lower dead point in the cylinder  41  by a rotation of the crankshaft  21 , the refrigerant is drawn into the cylinder  41  and discharged to outside of the cylinder  41  after being compressed. In other words, the refrigerant is drawn into the cylinder head  43  after orderly passing through the evaporator, the suction pipe  51  and the suction muffler  50 . When the suction valve (not shown) formed at the valve assembly  42  is opened, the refrigerant is drawn into the cylinder  41 . After that, when the discharge valve (not shown) is opened, the refrigerant compressed in the cylinder  41  is discharged to the cylinder head  43 , and flows to a condenser (not shown) of the freezing apparatus through the discharge muffler  60 . 
     However, for the reciprocating compressor with the above construction, a general amount of the refrigerant drawn into the cylinder is only 60 to 70% compared to an amount of the refrigerant discharged by the piston  32 . In other words, in a conventional reciprocating compressor, volume efficiency is 60 to 70%. The low volume efficiency is due to leakage of the refrigerant between the valve assembly  42  and the cylinder  41  and between the piston  32  and the cylinder  41 , clearance volume formed between an upper end of the piston  32  and the valve assembly  42  when the piston reaches the upper dead point, and expansion of the refrigerant by the temperature inside of the cylinder  41 . 
     When the volume efficiency is low, the compressing efficiency of the compressor is also low, thus the volume efficiency should be increased for a compressor with a high efficiency. 
     SUMMARY OF THE INVENTION 
     The present invention has been made to overcome the above-mentioned problems of the related art. Accordingly, it is an object of the present invention to provide a supercharging device of a hermetic compressor capable of increasing a volume efficiency by drawing in a great deal of refrigerant to a cylinder. 
     The above object of the present invention is accomplished by providing a super charging device of a hermetic compressor comprising a suction chamber connected with a refrigerant suction pipe and the cylinder, wherein the suction chamber is formed at one side of a cylinder block; a suction fan rotatably disposed in the suction chamber for being rotated in accordance with a rotation of a crankshaft; and transmitting means for transmitting the rotation force of the crankshaft to the suction fan. 
     Here, the transmitting means comprises a driving pulley formed on the crankshaft; a driven pulley formed on a rotating shaft of the suction fan; and a belt connecting the driving pulley and the driven pulley. Alternatively, the transmitting means can comprise a driving gear formed on the crankshaft; a driven gear formed on the rotating shaft of the suction fan; and an idle gear connecting the driving gear and the driven gear. 
     On the other hand, the suction chamber comprises a cylindric body protruded from a lower side of the cylinder block and a semi-spherical cover for shielding the body. 
     According to the supercharging device of the present invention, since the suction fan is rotated by being connected with the crankshaft, and transmits the refrigerant of the suction chamber, the amount of the refrigerant drawn into the cylinder is increased, and consequently, the volume efficiency of the compressor is increased. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The described objects and features of the present invention will be more apparent by explaining the preferred embodiment of the present invention by referring to the appended drawings, in which: 
     FIG. 1 is a sectional view showing a conventional reciprocating compressor; 
     FIG. 2 is a partial exploded perspective view showing a compressor having a supercharging device according to one preferred embodiment of the present invention; 
     FIG. 3 is a sectional view showing connection status of the compressor of FIG. 2; 
     FIG. 4 is a bottom view showing a cylinder block partially cut of the compressor of FIG. 2; and 
     FIG. 5 is a partial sectional view showing a compressor having a supercharging device according to another preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     From now on, the preferred embodiments of the present invention will be described by referring to the accompanying drawings. However, a hermetic compressor having a supercharging device according to the present invention has almost the same construction with a conventional compressor, thus the same referential numerals will be given to the same part of FIG. 1, and the description will be omitted. 
     As shown in FIG. 2, a reciprocating compressor having the supercharging device according to the present invention comprises a cylinder block  40  having a cylinder  41  formed therein, a cylinder head  43  installed at a front of the cylinder block  40  for sealing the cylinder  41 , and a valve assembly  42  disposed between the cylinder block  40  and the cylinder head  43 . 
     A piston  32  connected with a crankshaft  21  by a connecting rod  31  is formed inside of the cylinder  41 . The piston  32  compresses a refrigerant by reciprocating inside of the cylinder  41  with rotation of the crankshaft  21 . 
     As shown in FIGS. 2 and 3, the supercharging device according to one preferred embodiment of the present invention comprises a suction chamber  70  having a body  71  cylindrically protruded from a lower part of the cylinder block  40 , a semi-spherical cover  72  for sealing an opening of the body  71 , and a suction fan  80  rotatably disposed in the suction chamber  70 . 
     A driving pulley  91  is coaxially connected at a lower part of the crankshaft  21 , and a driven pulley  93  is integrally connected at an end of a rotating shaft  81  of the suction fan  80 . The driving pulley  91  and the driven pulley  93  are connected by a belt  92 . The belt  92  may be a timing belt or a V belt. When the crankshaft  21  rotates, the driving pulley  91  also rotates. The rotation of the driving pulley  91  is transferred to the driven pulley  93  by the belt  92 , and consequently, the suction fan  80  rotates in the suction chamber  70  with the rotation of the crankshaft  21 . 
     On the other hand, the size of the driving pulley  91  and the driven pulley  93  are formed such that the suction fan  80  rotates approximately 0.5 to 2 times when the crankshaft  21  rotates one time. It is preferable that the driving pulley  91  and the driven pulley  93  are approximately the same size so that the suction fan  80  can rotate one time when the crankshaft  21  rotates one time. 
     As shown in FIG. 4, the suction chamber  70  is connected with the cylinder head  43  through a suction passage  44  penetrating one side of the body  71  and a front side of the cylinder block  40 . In addition, the suction chamber  70  is connected with the evaporator (not shown) through a suction pipe  51  penetrating an upper side of the cylinder block  40 . Therefore, the refrigerant drawn into the suction chamber  70  through the suction pipe  51  is drawn into the cylinder head  43  through the suction passage  44 . The refrigerant in the cylinder head  43  is drawn into the cylinder  41  through the valve assembly  42 , when the piston  32  moves to a lower dead point of the cylinder  41 . 
     Meanwhile, a discharge muffler  60  is disposed in parallel to the suction chamber  70  at a lower side of the cylinder block  40 . The discharge muffler  60  comprises a body  61  cylindrically protruded from a lower side of the cylinder block  40 , and a semi-spherical cover  62  for sealing an opening of the body  61 . The discharge muffler  60  is connected with the cylinder head  43  through a refrigerant discharge passage  45  penetrating the one side of the body  61  and the front side of the cylinder block  40 . A refrigerant discharge pipe  100  is connected with the cover  62  for supplying the refrigerant to a condenser (not shown). Accordingly, the refrigerant in the cylinder  41  is drawn into the discharge muffler  60  by orderly passing through the cylinder head  43  and the discharging passage  45 . After that, the refrigerant flows to the condenser through the discharge pipe  100 . 
     For a compressor having the above construction, when the crankshaft  21  rotates, the piston  32  reciprocates in the cylinder  41 , and the refrigerant is drawn into the cylinder  41  after orderly passing through the suction pipe  51 , the suction chamber  70  and the cylinder head  43 . At this time, the suction fan  80  rotates in the suction chamber  70  in accordance with the rotation of the crankshaft  21 . The refrigerant is drawn into the suction chamber  70  through the suction pipe  51  and flows to the inside of the cylinder  41 . As described above, since the suction fan  80  moves the refrigerant forcefully, the amount of the refrigerant drawn into the cylinder  41  is increased, and thus, the volume efficiency of the compressor can be increased almost around 90%. 
     FIG. 5 shows a supercharging device according to another preferred embodiment of the present invention. 
     As shown in FIG. 5, the supercharging device according to another preferred embodiment has a difference in transmitting the rotation of the crankshaft  21  to the suction fan  80  compared to the supercharging device of FIG.  2 . In other words, a driving gear  94  is coaxially connected with a lower end of the crankshaft  21 , and a driven gear  96  is integrally connected with a rotating shaft of the suction fan  80 . The driving gear  94  and the driven gear  96  are connected by an idle gear  95 . When the crankshaft  21  rotates, the driving gear  94 , the idle gear  95  and the driven gear  96  rotate, and accordingly, the suction fan  80  rotates in the suction chamber  70 . 
     As described above, according to the supercharging device of the present invention, since the suction fan  80  rotates with the crankshaft  21  and moves the refrigerant in the suction chamber  70  to the cylinder  41 , the amount of the refrigerant drawn into the cylinder  41  is increased and consequently, the volume efficiency of the compressor is also increased. 
     Moreover, for a compressor having the supercharging device according to the present invention unlike a conventional compressor, noise generated when the refrigerant is drawn is reduced in the suction chamber  70 . Thus a separate suction muffler (refer to  50  of FIG. 1) is not needed. Therefore, the number of parts is reduced, and thus the production cost will be lowered. 
     Although the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that the present invention should not be limited to the described preferred embodiments, and various changes and modifications can be made within the spirit and scope of the present invention as defined by the appended claims.