Patent Publication Number: US-7223083-B2

Title: Scroll compressor

Description:
BACKGROUND OF THE INVENTION  
   1. Field of the Invention 
   The present invention relates to a scroll compressor, and particularly, to a scroll compressor capable of increasing a discharge capacity without a size change. 
   2. Description of the Conventional Art 
   In general, a compressor converts mechanical energy into compression energy of a compressible fluid, and may be classified into a reciprocating type, a scroll type, a centrifugal type and a vane type. 
   Unlike the reciprocating compressor using a linear movement of a piston, the scroll compressor sucks, compresses and discharges a gas by using a rotor as the centrifugal type or the vane type compressor. 
   Such a scroll compressor is commonly used for an air conditioner. To improve cooling and heating efficiency of the air conditioner, a scroll compressor which can vary its capacity has been recently required. 
     FIG. 1  is a longitudinal sectional view showing a conventional scroll compressor. 
   As shown, the conventional scroll compressor includes: a casing  1  provided with a gas suction pipe (SP) and a gas discharge pipe (DP); a main frame  2  and a sub frame (not shown) fixedly installed at upper and lower sides of the casing  1 , respectively; a driving motor  3  mounted between the main frame  2  and the sub frame, for generating a rotary force; a rotary shaft  4  fixed at the center of the driving motor  3  and penetrating the center of the main frame  2  to transfer a rotary force of the driving motor  3 ; a fixed scroll  5  fixedly installed on an upper surface of the main frame  2 ; an orbiting scroll  6  put on an upper surface of the main frame  2  and orbiting in a state of being interlocked with the fixed scroll  5  to thereby form a compression chamber (P); a self-rotation preventing member  7  (Oldham&#39;s ring) installed between the orbiting scroll  6  and the main frame  2 , for preventing self-rotation of the orbiting scroll  6 ; and a discharge cover  8  coupled to an upper surface of the fixed scroll, for dividing the inside of the casing  1  into a low pressure portion (S 1 ) and a high pressure portion (S 2 ). 
   Generally, the fixed scroll  5  fixed at an upper portion of the main frame  2  and the orbiting scroll  6  rotatably installed between the fixed scroll  5  and the main frame  2  are referred to as a compression unit. 
   A boss receiving portion  2   b  for an orbiting movement of a boss portion  6   b  of the orbiting scroll  6  is formed at a central portion of the main frame  2 , and a shaft hole  2   a  for supporting the rotary shaft  4  is formed at the center of the boss receiving portion  2   b.    
   A wrap  5   a  forming a compression chamber (P) by being interlocked with a wrap  6   a  of the orbiting scroll  6  to be explained later is formed at a lower surface of the fixed scroll  5  as an involute shape, and a suction hole  5   b  is formed at an outermost edge of the wrap  5   a . A discharge hole  5   c  communicating with the high pressure portion (S 2 ) of the casing  1  is formed near the central portion of the fixed scroll  5 . 
   A wrap  6   a  is formed at an upper surface of the orbiting scroll  6  as an involute shape and is interlocked with the wrap  5   a  of the fixed scroll  5 . A boss portion  6   b  coupled to an eccentric portion  4   a  of the rotary shaft  4  and orbiting within the boss receiving portion  2   b  of the main frame  2  is formed at a central portion of a lower surface of the orbiting scroll. 
   The conventional scroll compressor having such a structure is operated in the following manner. 
   When the rotary shaft  4  of the driving motor  3  rotates by applied power, the orbiting scroll  6  does not rotate but orbits by the self-rotation preventing member  7 . 
   At this time, a compression chamber (P) is formed between the wrap  6   a  of the orbiting scroll  6  and the wrap  5   a  of the fixed scroll  5 . By a constant orbiting movement of the orbiting scroll  6 , the compression chamber (P) moves a refrigerant gas, which has been introduced from the suction hole  5   b , toward the discharge hole  5   c , and then discharges the gas. 
   In other words, the refrigerant gas is sucked into the low pressure portion (S 1 ) of the casing  1  through the gas suction pipe (SP), is introduced toward an outermost edge of the compression chamber (P) through the suction hole  5   b  of the fixed scroll  5 , and then is compressed, gradually moving toward the inside of the compression chamber (P) by a continuous orbiting movement of the orbiting scroll  6 . The compressor refrigerant gas is discharged to the high pressure portion (S 2 ) of the casing  1  through the discharge hole  5   c  of the fixed scroll  5 . 
   However, the conventional scroll compressor having such a structure has a limit in increasing its capacity because the refrigerant gas is compressed only in the compression chamber (P) formed by the orbiting scroll  6  and the fixed scroll  5 . 
   SUMMARY OF THE INVENTION 
   Therefore, an object of the present invention is to provide a scroll compressor capable of increasing a capacity while maintaining the size of the compressor. 
   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 scroll compressor comprising: a casing; a driving motor fixedly installed in the casing; a frame fixedly installed inside the casing, for supporting a rotary shaft of the driving motor, wherein a ring shaped partition wall protrudes from a bottom of a boss receiving portion formed at a central portion of the frame, a vane side suction hole is formed at one side of the bottom of the boss receiving portion outside the partition wall, and a pair of vane side discharge holes are formed at the other side of the bottom; a fixed scroll fixedly installed at the frame, and having a first suction hole at its outermost edge and a first discharge hole at its central portion; an orbiting scroll forming a first compression chamber by being interlocked with the fixed scroll, orbiting by rotation of the rotary shaft, and having a boss portion for insertion of the rotary shaft and an orbiting vane encompassing the boss portion, wherein the boss portion is formed at a central portion of a lower portion of the orbiting scroll and the orbiting vane is formed at an outer edge of the lower portion of the orbiting scroll at a certain interval from the boss portion; a self-rotation preventing member interposed between the frame and the orbiting scroll, for preventing self-rotation of the orbiting scroll and leading an orbiting movement; and a slide block positioned between the vane side suction hole and a pair of vane side discharge holes, inserted in the orbiting vane to be slidable in a radial direction of the frame, and forming a second compression chamber outside and inside the orbiting vane. 
   A slit is formed at the orbiting vane, and the slide block is slidably inserted in the slit. 
   The second compression chamber comprises an inner second compression chamber formed inside the orbiting vane and an outer second compression chamber formed outside the orbiting vane, and a pair of vane side discharge holes are an outer vane side discharge hole positioned outside the orbiting vane and an inner vane side discharge hole positioned inside the orbiting vane. 
   Preferably, a diameter of the vane side suction hole is greater than that of each vane side discharge hole. 
   The vane side suction hole is positioned extendedly on the inner second compression chamber and the outer second compression chamber, and the outer vane side discharge hole is positioned extendedly on the outer second compression chamber and the inner vane side discharge hole is positioned extendedly on the inner second compression chamber. 
   The vane side suction hole is connected to a low pressure portion of the casing, and the vane side discharge hole is connected to a high pressure portion of the casing. 
   Preferably, the slide block is installed to be in contact with an outer circumferential surface of the partition wall, and curved portions are formed at both sides of the slide block. 
   The boss portion is positioned at an outer circumferential surface of the rotary shaft centering on the rotary shaft, the partition wall is positioned at an outer edge of the boss portion, and the orbiting vane is positioned at an outer edge of the partition wall. 
   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 unit 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 sectional view showing a part of a conventional scroll compressor; 
       FIG. 2  is an exploded perspective view showing a compression unit of the conventional scroll compressor; 
       FIG. 3  is a longitudinal sectional view for describing a vane side suction hole of a scroll compressor in accordance with the present invention; 
       FIG. 4  is a longitudinal sectional view for describing a vane side discharge hole of the scroll compressor in accordance with the present invention; 
       FIG. 5  is an exploded perspective view showing a compression unit of the scroll compressor in accordance with the present invention; 
       FIG. 6  is a bottom perspective view showing an orbiting scroll of the scroll compressor in accordance with the present invention; 
       FIG. 7  is a cross-sectional view for describing a vane side compression unit of the scroll compressor in accordance with the present invention; and 
       FIGS. 8A to 8D  are cross-sectional views for describing the operation of the vane side compression unit. 
   

   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. 
     FIG. 3  is a longitudinal sectional view for describing a vane side suction hole of a scroll compressor in accordance with the present invention,  FIG. 4  is a longitudinal sectional view for describing a vane side discharge hole of the scroll compressor in accordance with the present invention,  FIG. 5  is an exploded perspective view showing a fixed scroll side compression unit o in accordance with the present invention,  FIG. 6  is a bottom perspective view showing an orbiting scroll of the scroll compressor in accordance with the present invention, and  FIG. 7  is a cross-sectional view for describing a vane side compression unit the scroll compressor in accordance with the present invention. 
   As shown, the scroll compressor  100  in accordance with the present invention includes: a casing  110  provided with a gas suction pipe (SP) and a gas discharge pipe (DP); a main frame  120  and a sub frame (not shown) fixedly installed at upper and lower sides of the casing  110 , respectively; a driving motor  130  mounted between the main frame  120  and the sub frame, for generating a rotary force; a rotary shaft  140  fixed at the center of the driving motor  130  and penetrating the center of the main frame  120  to transfer a rotary force of the driving motor  130 ; a fixed scroll  150  fixedly installed on an upper surface of the main frame  120 ; an orbiting scroll  160  put on the upper surface of the main frame  120  and orbiting in a state of being interlocked with the fixed scroll  150  to thereby form a compression chamber  200 ; a self-rotation preventing member  170  (Oldham&#39;s ring) installed between the orbiting scroll  160  and the main frame  120 , for preventing self-rotation of the orbiting scroll  160 ; and a discharge cover  180  coupled to an upper surface of the fixed scroll  150  and dividing the inside of the casing  110  into a low pressure portion (S 1 ) and a high pressure portion (S 2 ). 
   In the scroll compressor in accordance with the present invention, the main frame  120 , the fixed scroll  150  fixed at an upper portion of the main frame  120 , and the orbiting scroll  160  rotatably installed between the fixed scroll  150  and the main frame  120  are referred to as a fixed scroll side compression unit. 
   A partition wall  123  of the main frame  120 , an orbiting vane  163  of the orbiting scroll  160  and a slide block  190  which are to be explained later are referred to as to a vane side compression unit. 
   A space for an orbiting movement of a boss portion  162  of the orbiting scroll  160 , namely, a boss receiving portion  121  is formed at a central portion of the main frame  120 , and a shaft hole  122  for supporting the rotary shaft  140  is formed at the center of the boss receiving portion  121 . 
   A wrap  151  forming a first compression chamber  200  by being interlocked with a wrap  161  of the orbiting scroll  160  to be explained later is formed at a lower surface of the fixed scroll  150  as an involute shape, and a suction hole  152  is formed at an outermost edge of the wrap  151 . A discharge hole  153  communicating with the high pressure portion (S 2 ) of the casing  110  is formed near the center of the fixed scroll  150 . 
   A wrap  161  is formed at an upper surface of the orbiting scroll  160  as an involute shape and is interlocked with the wrap  151  of the fixed scroll  150 . A boss portion  162  coupled to an eccentric portion  141  of the rotary shaft  140  and orbiting within the boss receiving portion  121  of the main frame  120  is formed at a central portion of a lower surface of the orbiting scroll  160 . 
   As for characteristics of the present invention, a partition wall  123  having a ring shape protrudes from a bottom of the boss receiving portion  121  of the frame  120 , a vane side suction hole  124  is formed at one side of the bottom of the boss receiving portion  121  outside the partition wall  123 , and a pair of vane side discharge holes  125  and  126  are formed at the other side of the bottom. 
   Also, an orbiting vane  163  is formed at a certain distance from the boss portion  162  of the orbiting scroll  160 , surrounding the boss portion  162 , and a slit  165  is formed at one side of the orbiting vane  163 . 
   A slide block  190  is positioned between the vane side suction hole  124  and a pair of vane side discharge holes  125  and  126 . The slide block  190  is inserted in the orbiting vane  163  to be slidable in a radial direction of the frame  120  and forms a second compression chamber  300  outside and inside the orbiting vane  163 . 
   In other words, the second compression chamber  300  is a compression space formed between the orbiting vane  163  and the slide block  190  when the slide block  190  is inserted in the slit  165  comes in contact with an outer circumferential surface of the partition wall  123 . 
   The second compression chamber  300  may be divided into an inner second compression chamber  310  formed inside the orbiting vane  163  and an outer second compression chamber  320  formed outside the orbiting vane  163 . 
   Preferably, a curved portion  191  having the same curvature as that of the outer circumferential surface of the partition wall  123  is formed at one end of the slide block  190 , so that the slide block  190  can be closely attached and contact with the outer circumferential surface of the partition wall  123 . Also, a curved portion  192  having the same curvature as that of an inner circumferential surface of the boss receiving portion  121  is preferably formed at the other end of the slide block  190 , so that the slide block  190  can be closely attached to the inner circumferential surface of the boss receiving portion  121 . 
   As shown in  FIGS. 8A and 8D , for the purpose of simplicity, as the inner second compression chamber  310  is divided into two by the orbiting vane  163  and the slide block  190 , one space of the inner second compression chamber  310  is referred to as a compression chamber  311 , and the other space thereof is referred to as a compression chamber  312 . Also, as the outer second compression chamber  320  is divided into two by the orbiting vane  163  and the slide block  190 , one space of the outer second compression chamber  320  is referred to as a compression chamber  321  and the other space is referred to as a compression chamber  322 . 
   A pair of vane side discharge holes  125  and  126  are an outer vane side discharge hole  125  positioned outside the orbiting vane  163  and an inner vane side discharge hole  126  positioned inside the orbiting vane  163 . 
   A diameter of the vane side suction hole  124  is preferably greater than that of each vane side discharge hole  124 ,  125 . 
   The vane side suction hole  124  is positioned extendedly on the inner second compression chamber  310  and the outer second compression chamber  320 , the outer vane side discharge hole  125  is positioned extendedly on the outer second compression chamber  320 , and the inner vane side discharge hole  126  is positioned extendedly on the inner second compression chamber  310 . 
   As shown in  FIG. 3 , the vane side suction hole  124  is connected to the low pressure portion (S 1 ) of the casing  110 , and the vane side discharge holes  125  and  126  are connected to the high pressure portion (S 2 ) of the casing  110 . 
   Accordingly, the boss portion  162  is positioned at an outer circumferential surface of the rotary shaft  140  centering on the eccentric portion  141  of the rotary shaft  140 , the partition wall  123  is positioned at an outer edge of the boss portion  162 , and the orbiting vane  163  is positioned at an outer edge of the partition wall  123 . 
   The operation of the scroll compressor in accordance with the present invention having such a structure will now be described. 
   Namely, when the driving motor  130  rotates the rotary shaft  140  upon receiving power, the orbiting scroll  160  orbits as long as an eccentric distance, thereby forming a first compression chamber  200  between the wrap  161  of the orbiting scroll  160  and the wrap  151  of the fixed scroll  150 . The first compression chamber  200  consecutively moves toward the center by the constant orbiting movement of the orbiting scroll  160 , thereby reducing its volume. In such a process, the refrigerant gas is sucked into the scroll side suction hole  151  from the low pressure portion (S 1 ) of the casing  110 , is gradually compressed, and then is discharged to the high pressure portion (S 2 ) of the casing  110  through the scroll side discharge hole  153  of the fixed scroll  150 . 
   Also, because of the orbiting vane  163  formed at a rear surface of the orbiting scroll  160 , a lower surface, and the slide block  190  linearly moving in a radial direction, provided at the orbiting vane  163  and installed between the vane side suction hole  124  and each vane side discharge hole  125  and  126 , an outer second compression chamber  320  and an inner second compression chamber  310  having a phase difference of 180 degrees are formed between an outer circumferential surface of the orbiting vane  163  of the orbiting scroll  160  and an inner circumferential surface of the boss receiving portion  121  of the main frame  120  and between an inner circumferential surface of the orbiting vane  163  and an outer circumferential surface of the partition wall  123  of the main frame  120 , respectively. 
   The refrigerant gas is sucked through the vane side suction hole  124  in the casing  110 , compressed, and then discharged through both vane side discharge holes  125  and  126 . The refrigerant gas discharged from the second compression chamber is discharged to the gas discharge pipe (DP) through a gas passage  127 , together with a refrigerant gas discharged from the first compression chamber  200 . Therefore, the scroll compressor  100  in accordance with the present invention can raise its discharge capacity by discharging a refrigerant gas from not only the first compression chamber but also the second compression chamber. 
     FIGS. 8A to 8D  are cross-sectional views for describing the operation of the vane side compression unit. Hereinafter, processes for suction, compression, discharge of a refrigerant gas in the second compression chamber will now be described with reference to  FIGS. 8A to 8D . 
   First, as shown in  FIG. 8A , at an initial stage, the vane side suction hole  124  communicates with a compression chamber  311  of the inner second compression chamber  311 , so that a refrigerant gas is sucked only to the compression chamber  311  of the inner second compression chamber  310 . At the same time, discharge of the refrigerant gas through the vane side discharge hole  126  is started in a compression chamber  312  of the inner second compression chamber  310 , which is positioned on the opposite side of the compression chamber  311  on the basis of the slide block  190 . Meanwhile, in the outer second compression chamber  320 , suction of the refrigerant gas through the vane side suction hole  124  is completed, and compression is started. 
   Then, as shown in  FIG. 8B , at a position of the orbiting vane  163  having orbited clockwise from the initial position as much as an angular distance of 90 degrees, a very small amount of a refrigerant gas is sucked to a compression chamber  321  of the outer second compression chamber  320  through the vane side suction hole  124 , and simultaneously, compression of a refrigerant gas further proceeds in a compression chamber  322  of the outer second compression chamber  320 , which is positioned on the opposite side of the compression chamber  321  on the basis of the slide block  190 . Meanwhile, in the compression chamber  311  of the inner second compression chamber  310 , a suction area gets wider and a refrigerant gas is sucked through the vane side suction hole  124 . At the same time, compression of a refrigerant gas is completed in the compression chamber  312  of the inner second compression chamber  310 . 
   Then, as shown in  FIG. 8C , at a position of the orbiting vane  163  having further orbited clockwise at an angular distance of another 90 degrees, a refrigerant gas is sucked into the compression chamber  321  of the outer second compression chamber  320  through the vane side suction hole  124 , and simultaneously, a refrigerant gas is discharged from the compression chamber  322  of the outer second compression chamber  320  through the vane side discharge hole  125 . Meanwhile, in the inner second compression chamber  310 , suction of a refrigerant gas through the vane side suction hole  124  is completed, and compression is started. 
   Next, as shown in  FIG. 8D , at a position where the orbiting vane  163  having orbited at an angular distance of another 90 degrees, a refrigerant gas is continuously sucked into the compression chamber  321  of the outer second compression chamber  320  through the vane side suction hole  124 , and simultaneously, the compression in the compression chamber  322  of the outer second compression chamber  320  is completed. Meanwhile, suction of the refrigerant gas into the compression chamber  311  of the inner second compression chamber  310  is started through the vane side suction hole  124 . At the same time, compression is continued in the compression chamber  312  of the inner second compression chamber  310 . A series of such processes of sucking, compressing and discharging of a refrigerant gas are repetitively carried out. 
   As described above, when the orbiting scroll  160  orbits, it forms the first compression chamber together with the fixed scroll  150  and also forms a second compression chamber  300  together with the main frame  120 . Accordingly, a capacity of the compression can be greatly increased without enlarging a size of the compressor. 
   As so far described, the scroll compressor in accordance with the present invention, a first compression chamber is formed between the orbiting scroll and the fixed scroll, and a second compression chamber is additionally formed between the orbiting scroll and the main frame, so that a refrigerant gas can be compressed in both compression chambers while the orbiting scroll orbits, thereby obtaining a capacity greater than that of other compressors having the same size. 
   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.