Abstract:
In a scroll compressor, a sealing portion of a discharge cover placed between a suction spacer and a discharge space is formed to be spaced apart in an axial direction from a fixed scroll, whereby the discharge cover is in contact with a fixture in an axial direction only on a single circumference, facilitating fabrication and assembling of the discharge cover. Also, after assembly, when the discharge cover is pressurized toward the fixed scroll by a discharge pressure of a refrigerant discharged to the discharge space, the discharge cover does not transfer pressurization force to the fixed scroll, thus reducing a frictional loss between the fixed scroll and an orbiting scroll.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present disclosure relates to subject matter contained in priority Korean Application No. 10-2011-0092208, filed on Sep. 9, 2011, which is herein expressly incorporated by reference in its entirety. 
     1 Field of the Invention 
     The present invention relates to a scroll compressor and, more particularly, to a low pressure scroll compressor in which an inner space of a container is divided into a suction space and a discharge space by a discharge cover. 
     2 Description of the Related Art 
     A scroll compressor is a compressor for compressing a refrigerant gas by changing the volume of a compression chamber formed by a pair of opposing scrolls. In comparison to a reciprocating compressor or a rotary compressor, a scroll compressor has high efficiency, low vibration and noise, and can be reduced in size and weight, and thus, such a scroll compressor is widely used, especially, in air-conditioners. 
     A scroll compressor may be divided into a low pressure scroll compressor and a high pressure compressor according to a pressure of a refrigerant filled in an inner space of the container thereof. In the low pressure scroll compressor, a suction pipe communicates with an inner space of the container and a refrigerant is indirectly sucked into a compression chamber through the inner space. Meanwhile, in the high pressure scroll compressor, a suction pipe directly communicates with a suction side of a compression unit and a refrigerant is directly sucked into the compression chamber, without passing through an inner space of the container. 
       FIG. 1  is a vertical sectional view of a related art low pressure scroll compressor. As illustrated, in the related art low pressure scroll compressor, an inner space of the container  10  is divided into a suction space S 1  and a discharge space S 2 . The inner space of the container  10  is divided into the suction space S 1  and the discharge space S 2  by a main frame  20  or a fixed scroll  50 , or may be divided into the suction space S 1  and the discharge space S 2  by a discharge plenum (not shown) fixed to an upper surface of the fixed scroll  50  or a discharge cover  80  as shown in  FIG. 1   
     As shown in  FIG. 2 , the related art discharge cover  80  has an annular shape. An outer circumference side of the discharge cover  80  is airtightly coupled to the container  10 , and an inner circumference side of the discharge cover  80  is fixedly coupled to an upper surface of the fixed scroll  50  to cover a discharge opening  53 . The outer circumferential surface of the discharge cover  80  is bent and a support protrusion  81  having a band-like shape is formed on the outer circumferential surface. The support protrusion  81  is inserted between a shell  11  of the container  10  and an upper cap  12  and supported in an axial direction. A lower surface of the inner circumference of the discharge cover  80  is fixed to, tightly attached to and supported by an upper surface of the fixed scroll  50  in an axial direction in order to prevent a refrigerant discharged to the discharge space S 2  from being leaked to the suction space S 1 . Reference numeral  13  denotes a lower cap, reference numeral  30  denotes a lower frame, reference numeral  40  denotes a driving motor, reference numeral  41  is a stator, reference numeral  42  denotes a rotor, reference numeral  43  denotes a crank shaft, reference numeral  51  denotes a fixed wrap, reference numeral  52  denotes a suction opening, reference numeral  60  denotes an orbiting scroll, reference numeral  61  denotes an orbiting wrap, reference numeral  70  denotes an oldhamring, reference letters SP denote a suction pipe, and reference letters DP denote a discharge pipe. 
     However, in the related art scroll compressor, both the outer circumference side and the inner circumference side of the discharge cover  80  are fixed in an axial direction, but since a discharged refrigerant pressurizes the inner circumferential side (i.e., region ‘A’ in  FIG. 2 ), the fixed scroll  50  is pressed toward the orbiting scroll  60  by the pressurization force, increasing a frictional loss between the fixed scroll  50  and the orbiting scroll  60 . 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention provides a scroll compressor in which a discharge cover can be easily processed and assembled and a fixed scroll is prevented from being deformed toward an orbiting scroll by a pressurization force of a refrigerant discharged to a discharge space, thus reducing a frictional loss between the fixed scroll and the orbiting scroll. 
     According to an aspect of the present invention, there is provided a scroll compressor including: a container having an inner space; a fixed scroll installed in the inner space of the container; an orbiting scroll installed to be engaged with the fixed scroll to make a gyrational movement; and a discharge cover dividing an inner space of the container into a suction space and a discharge space, wherein a sealing portion is provided between the fixed scroll and the discharge cover in order to seal the suction space and the discharge space, and the sealing portion is formed such that the fixed scroll and the discharge cover are spaced apart from each other in an axial direction when the compressor is stopped. 
     According to another aspect of the present invention, there is provided a scroll compressor including: a shell having open upper and lower ends; an upper cap covering the upper end of the shell; a lower cap covering the lower end of the shell; a frame fixedly coupled to the shell; a fixed scroll supported by the frame and having a suction opening and a discharge opening; an orbiting scroll engaged with the fixed scroll to make a gyrational movement to form a continuously moving compression chamber; and a discharge cover dividing the suction opening and the discharge opening of the fixed scroll, wherein a annular first sealing portion is formed to be protruded in the vicinity of the discharge opening of the fixed scroll, and a second sealing portion is formed to be bent on the discharge cover and inserted into the first sealing portion. 
     According to another aspect of the present invention, there is provided a scroll compressor including: a container; a frame fixed in an inner space of the compressor container; a fixed scroll supported by the frame and having a suction opening and a discharge opening; an orbiting scroll engaged with the fixed scroll to make a gyrational movement to form a continuously moving compression chamber; and a discharge cover dividing the inner space of the container into a suction space communicating with the suction opening and a discharge space communicating with the discharge opening, wherein a sealing portion is formed on an inner circumference side of the discharge cover to separate the suction space and the discharge space, a support is formed on an outer circumference side of the discharge cover to support the discharge cover in an axial direction, and when the compressor is stopped, the sealing portion is spaced apart from the fixed scroll in an axial direction and the support portion comes in contact with the frame or the fixed scroll in the axial direction. 
     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 
         FIG. 1  is a view showing an electromagnetic switching device according to an embodiment of the present invention; 
         FIG. 2  is an enlarged view illustrating a coupled state of a fixed scroll and a discharge cover in  FIG. 1 ; 
         FIG. 3  is a vertical sectional view illustrating an example of a scroll compressor according to an embodiment of the present invention; 
         FIG. 4  is an enlarged view illustrating a coupled state of a fixed scroll and a discharge cover in  FIG. 3 ; 
         FIGS. 5 and 6  are enlarged views illustrating a portion ‘A’ and a portion ‘B’ in  FIG. 4 , respectively; 
         FIG. 7  is a cross-sectional view showing a state in which a discharge cover absorbs a pressurization force of a discharge gas in  FIG. 4 ; and 
         FIGS. 8 and 9  are views illustrating the results of experimentation showing a comparison between a deformation degree of the fixed scroll when the sealing portion of the discharge cover has an overlap section with the fixed scroll in an axial direction ( FIG. 8 ) and when the sealing portion does not have an overlap section ( FIG. 9 ) according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A scroll compressor according to an embodiment of the present invention will be described with reference to the accompanying drawings. 
     As illustrated in  FIG. 3 , in the scroll compressor according to an embodiment of the present invention, an inner space of a container  10  may be divided into a suction space S 1  as a low pressure part and a discharge space S 2  as a high pressure part. A driving motor  40  for generating a rotational force may be installed in the suction space S 1  of the container  10 . A main frame  20  may be fixedly installed between the suction space S 1  and the discharge space S 2  of the container  10 . A subframe  30  may be installed on a lower end of the suction space S 1 . 
     The driving motor  40  may be installed between the main frame  20  and the subframe  30 , and a fixed scroll  50  may be fixedly installed on an upper surface of the main frame  20 . 
     An orbiting scroll  60  may be installed between the main frame  20  and the fixed scroll  50  such that it is gyrational. The orbiting scroll  60  may be eccentrically coupled to a crank shaft  43  of the driving motor  40  to form a pair of compression chambers P continuously moving together with the fixed scroll  50 . An oldhamring  70  may be installed between the fixed scroll  50  and the orbiting scroll  60  in order to prevent the orbiting scroll  60  from being rotated. 
     The container  10  may include a cylindrical shell  11  and an upper cap  12  and a lower cap  13  covering an upper opening end of the shell  11  and a lower opening end of the shell  11 . 
     A suction pipe SP may be coupled to communicate with the suction space S 1  of the container  10 , and a discharge pipe DP may be coupled to communicate with the discharge space S 2 . 
     The container  10  may have the hermetically sealed discharge space S 2 , and the suction space S 1  as a low pressure part and the discharge space S 2  as a high pressure part may be divided by a discharge plenum (not shown) fixedly coupled to the fixed scroll  50 , or as shown in  FIGS. 3 and 4 , the inner space of the container  10  may be divided into the suction space S 1  and the discharge space S 2  by a discharge cover  100  tightly attached to an inner circumferential surface of the container  10 . 
     The entirety or a portion of an outer circumferential surface of the main frame  20  may be fixedly welded to an inner circumferential surface of the shell  11  of the container  10 . However, as shown in  FIG. 6 , a support protrusion  21  having a band-like shape or a protuberance-like shape is formed on an outer circumferential surface of the main frame  20  and mounted on an upper opening end  11   a  of the shell  11  of the container  10  so as to be supported in an axial direction. When the outer circumferential surface of the main frame  20  is tightly attached to the inner circumferential surface of the shell  11  of the container  10 , a communication hole (not shown) or a communication recess (not shown) allowing the suction space S 1  and a suction opening  53  (to be described) to communicate with each other may be formed. 
     In the fixed scroll  50 , a fixed wrap  52  may be formed to be protruded from a lower surface of a disk plate  51  to constitute a compression chamber P together with an orbiting wrap  62  of the orbiting scroll  60 . In the fixed scroll  50 , a suction opening  53  is formed on an outer circumferential surface of the disk plate  51  to allow the suction space S 1  of the container  10  and the compression chamber P to communicate with each other. A discharge opening  54  may be formed at a central portion of the disk plate  51  of the fixed scroll  50  to allow the compression chamber P and the discharge space S 2  of the container  10  to communicate with each other. 
     The disk plate  51  of the fixed scroll  50  may have an annular shape and fixedly coupled to an upper surface of the main frame  20 . When the support protrusion  21  is not provided in the main frame  20 , the same support protrusion (not shown) may be formed on an outer circumferential surface of the disk plate  51  of the fixed scroll  50 . 
     The discharge cover  100  may be installed on an upper surface of the disk plate  51  of the fixed scroll  50  in order to separate the interval space of the container  10  into the suction space S 1  and the discharge space S 2 . 
     The discharge cover  100  may be formed by pressurizing a plate body having a certain thickness. When viewed from a plane, the discharge cover  100  may have an annular shape. A support portion  110  is formed on the outer circumference side of the discharge cover  100 , on which the support protrusion  21  of the main frame  20  or a support protrusion (not shown) of the fixed scroll  50  is mounted and supported in an axial direction. A sealing portion  120  may be formed on the inner circumferential side of the discharge cover  100  and is tightly attached to the disk plate  51  of the fixed scroll  50  in a radial direction to cover the vicinity of the discharge opening  54 . 
     The support portion  110  may be formed as a step by bending the outer circumference side of the discharge cover  100 , such that it is mounted on the support protrusion  21  of the main frame  20  or the support protrusion of the fixed scroll  50  on an inner circumferential surface of the discharge cover  100 , Also, a fixing portion  130  may be formed as a step in the vicinity of an outer portion of the support portion  110  to allow the upper cap  12  to be fixedly mounted thereon. 
     The sealing portion  120  may be formed by bending an inner circumference side of the discharge cover  100  toward the fixed scroll  50 . To this end, as shown in  FIG. 5 , a first sealing portion  55  may be formed to have an annular shape and have a certain height on an upper surface of the disk plate  51  of the fixed scroll  50 , namely, in the vicinity of the discharge opening  54 , and a second sealing portion  121  may be formed to be inserted in the first sealing portion  55  and is in contact therewith in a radial direction in the inner circumference side of the discharge cover  100 . 
     A lower end of the second sealing portion  121  may be formed to be spaced apart by a certain interval from the upper surface  51   a  of the disk plate  51  of the fixed scroll  50 . Preferably, the second sealing portion  121  is formed to have a space t 1  so that a lower end  121   a  of the second sealing portion  121  is not brought into contact with an upper surface  51   a  of the fixed scroll  50  or is not excessively tightly contact therewith although a high pressure refrigerant discharged to the discharge space S 2  pressurizes the discharge cover  100 . 
     However, although not shown, the second sealing portion  121  may have an annular shape and planar shape, rather than being bent, so an inner circumferential surface thereof may be substantially in contact with an outer circumferential surface of the first sealing portion  55 . In this case, a lower surface of the vicinity (the second sealing portion  121 ) of the inner circumference side of the discharge cover  100  may be coupled such that it is spaced apart by a certain interval from the upper surface  51   a  of the fixed scroll  50 . 
     Meanwhile, preferably, the discharge cover  100  may have a sloped surface portion  140  formed to be downwardly sloped toward a support portion  110  between the second sealing portion  121  and the support portion  110  to distribute a gas pressure. To this end, preferably, the fixed scroll  50  is formed to be sloped downwardly toward the outer circumference of the first sealing portion  55 . 
     Reference numeral  41  denotes a stator and reference numeral  42  denotes a rotor. 
     The scroll compressor according to the present embodiment has the following operational effect. 
     Namely, when power is applied to the driving motor  40  to generate rotational force, the orbiting scroll  60  eccentrically coupled to the crank shaft  43  of the driving motor  40  makes a gyrational movement to form a pair of (or two) compression chambers P continuously moving between the orbiting scroll  60  and the fixed scroll  50 . The compression chambers P are formed continuously in several stages such that a volume thereof is gradually reduced toward the discharge opening (or a discharge chamber)  54  from the suction opening (or the suction chamber)  53 . 
     Then, the refrierant sucked from the outside of the container  10  is introduced into the suction space S 1 , a low pressure portion, of the container  10  through the suction pipe SP, and the low pressure refrigerant the suction space S 1  is introduced through the suction opening  53  of the fixed scroll  50  and move in a direction of a final compression chamber by the orbiting scroll  60  so as to be compressed, and then, discharged to the discharge space S 2  of the container  10  through the discharge opening  54  of the fixed scroll  50  from the final compression chamber. This sequential process is repeatedly performed. 
     Here, since the discharge space S 2  is separated from the suction space S 1  by the sealing portion  120  of the discharge cover  100 , the refrigerant discharged to the discharge space S 2  moves to a refrigerating cycle through the discharge pipe DP, rather than flowing backward to the suction space S 1 . 
     Here, when the sealing portion (namely, the second sealing portion)  121  of the discharge cover  100  is tightly attached to the upper surface  51   a  of the fixed scroll  50  in the axial direction, the fixed scroll  50  may be pressurized toward the orbiting scroll  60  by the high pressure refrigerant discharged to the discharge space S 2  so as to be deformed, resulting in that a frictional loss is increased between the fixed scroll  50  and the orbiting scroll  60  to degrade performance of the compressor. 
     However, in the present embodiment, since the second sealing portion  121  of the discharge cover  100  is in contact with the first sealing portion  55  of the fixed scroll  50  only in the radial direction and coupled to maintain a certain space in the axial direction, although the discharge cover  100  is pressed by the discharged refrigerant, the sealing portion  120  of the discharge cover  100  does not pressurize the fixed scroll in the axial direction. Thus, the fixed scroll  50  and the orbiting scroll  60  are prevented from being excessively tightly attached to each other, thus preventing a degradation of efficiency of the compressor due to an increase in the frictional loss. 
       FIGS. 8 and 9  are views illustrating the results of experimentation showing a comparison between a deformation degree of the fixed scroll when the sealing portion of the discharge cover has an overlap section with the fixed scroll in an axial direction ( FIG. 8 ) and when the sealing portion does not have an overlap section ( FIG. 9 ) according to an embodiment of the present invention. 
     As illustrated, it can be seen that, when the discharge cover  100  and the fixed scroll  50  have an overlap section in the axial direction, a central portion of the fixed scroll  50  is severely loaded. However, when the discharge cover  100  and the fixed scroll  50  do not have an overlap section in the axial direction, the central portion of the fixed scroll  50  is relatively less loaded. Thus, it can be seen that when the sealing portion  120  of the discharge cover  100  is coupled to the fixed scroll  50  such that it does not overlap in the axial direction, the fixed scroll  50  is prevented from being deformed. 
     Meanwhile, when the second sealing portion  121  of the discharge cover  100  is not supported by the first sealing portion  55  of the fixed scroll  50  and only the support portion  110  of the discharge cover  100  is supported by the fixed scroll  50 , the main frame  20 , or the shell  11  of the container  10 , since only one point is supported in the axial direction, processing and assembling of the discharge cover  100  can be facilitated. Namely, when even the second sealing portion  121 , as well as the support portion  110  of the discharge cover  100  is in contact with the fixed scroll  50 , or the like, in the axial direction, since two points are supported, the discharge cover  100  should be more precisely processed and assembled. Thus, in the present embodiment, when only the support portion of the discharge cover is supported in the fixed scroll or the main frame in the axial direction while the sealing portion of the discharge cover is spaced art from the fixed scroll, processing or assembling process of the discharge coves: and the fixed scroll can be facilitated. 
     As the present invention may be embodied in several forms without departing from the 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 scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.