Abstract:
In a compressor including a sealed casing respectively communicating with a suction pipe and a discharge pipe; a cylinder assembly disposed in the sealed casing and having a suction path and a discharge path; a Z-plate partitioning the internal space of the cylinder assembly into plural compression spaces and sucking, compressing and discharging gas while being rotated by a motor part; a vane contacted to the both surfaces of the Z-plate and partitioning each compression space into a suction region and a compression region while performing a reciprocating motion; and a discharge muffler covered the both sides of the cylinder assembly and lowering noise of discharged gas, a compressor comprises at least one oil returning member installed on a discharge route between the discharge path of the cylinder assembly and the discharge pipe of the sealed casing in order to filter oil flowing with gas.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to a compressor using a vane, and more particularly, to a compressor having an oil returning apparatus which is capable of lowering oil leakage to outside of the compressor.  
         BACKGROUND ART  
         [0002]    In general, compressors are for converting mechanical energy into compression energy of compressive fluid, among them a freezing compressor is largely classified into a reciprocating compressor, a scroll compressor, a centrifugal compressor and a ratary compressor, etc.  
           [0003]    The present applicant has developed a Z-compressor with a novel concept, which can be classified as a rotary compressor, and filed an application for the invention to the Korean Industrial Patent Office (Application No. 10-1999-0042381, Application date Oct. 1, 1999), which has been laid open May 7, 2001 with a publication No. 2001-0035687.  
           [0004]    The above-mentioned Z-compressor will be described in detail with reference to accompanying drawing.  
           [0005]    [0005]FIG. 1 is a longitudinal sectional view illustrating the conventional Z-compressor.  
           [0006]    As shown in FIG. 1, the Z-compressor can be classified as a rotary compressor, and it includes a sealed casing  10 ; a motor part  20  disposed in the sealed casing  10  and generating a rotational force; and a compression part  30  for sucking, compressing and discharging gas by the rotational force of the motor part  20 .  
           [0007]    In the sealed casing  10 , a side portion communicates with a suction pipe  12  at which gas is sucked, and a upper portion communicates with a discharge pipe  14 .  
           [0008]    In addition, a internal bottom surface of the sealed casing  10  is filled with a certain amount of oil for lubricating and cooling a sliding portion and a heat generating portion inside the sealed casing  10 .  
           [0009]    The motor part  20  consists of a stator  22  and a rotor  23  as a general electric motor.  
           [0010]    The compression part  30  includes a cylinder assembly  31  disposed in the sealed casing  10  and forming a compression space for compressing gas sucked from the outside; a rotational shaft  24  for transmitting a rotational power generated in the rotor  23  of the motor part  20 ; a Z-plate  35  combined with the rotational shaft  24 , rotated together with it and partitioning the compression space into a first space V 1  and a second space V 2 ; and a first vane  38  and a second vane  39  respectively contacted to the upper surface and the bottom surface of the Z-plate  35  and partitioning the first space V 1  and the second space V 2  into a suction region and a compression region.  
           [0011]    The cylinder assembly  31  includes a cylinder  50 ; and a first bearing plate  40  and a second bearing plate  60  respectively fixed to the upper surface and the bottom surface of the cylinder  50  and forming a compression space with the cylinder  50 .  
           [0012]    Suction paths  52 ,  54  for sucking gas into the first space V 1  and the second space V 2  are respectively formed at the both sides of the cylinder  50  so as to communicate with the suction pipe  12 .  
           [0013]    The first and the second bearing plates  40 ,  60  are disc-shaped having a certain thickness and area, and they respectively include a journal portion  44 ,  64  extended from the center so as to have a certain height and outer diameter to receive the rotational shaft  24  rotatably; and a first vane slot  42  and a second vane slot  62  formed at the side of the journal portion  44 ,  64  to receive the first and the second vanes  38 ,  39 .  
           [0014]    In addition, a discharge path  46 ,  66  is respectively formed at the side of the first and the second vane slots  42 ,  62  to discharge compressed gas from the compression space.  
           [0015]    In addition, in order to reduce discharge noise of the compression gas discharged to the upper portion of the first bearing plate  40  and the lower portion of the second bearing plate  60 , a first discharge muffler  70  and a second. discharge muffler  80  covered the first and the second bearing plates  40 ,  60  respectively.  
           [0016]    In the first and the second discharge mufflers  70 ,  80 , in order to engage with the outer circumference of the first and the second bearing plates  40 ,  60  in the circumference direction, they respectively have an inner diameter corresponded to the outer diameter of the first and the second bearing plates  40 ,  60 , and fixation holes  74 ,  84  are formed at the central portion so as to have an inner diameter corresponded to the outer diameter of the journal portions  44 ,  64  of the first and the second bearing plates  40 ,  60 .  
           [0017]    Accordingly, a side of the first and the second discharge mufflers  70 ,  80  is tightly contacted to the outer circumference of the journal portions  44 ,  64  of the first and the second bearing plates  40 ,  60  respectively, and the other side of the first and the second discharge mufflers  70 ,  80  is tightly contacted to the outer circumference of the first and the second bearing plates  40 ,  60  respectively.  
           [0018]    In addition, outlets  72 ,  82  for discharging gas are respectively formed at a certain side of the first and the second discharge mufflers  70 ,  80 .  
           [0019]    The rotational shaft  24  has a certain outer diameter and a certain length, and it consists of a shaft portion  25  inserted into the journal portions  42 ,  62  of the first and the second bearing plates  40 ,  60  and a hub portion  26  circumferentially formed at the shaft portion  25  and combined with the Z-plate  35 .  
           [0020]    In addition, the rotational shaft  24  includes an oil path  27  penetrating the shaft portion  25  and an oil feeder  28  formed at the lower end of the oil path  27  to supply oil contained in the sealed casing  10  upwardly.  
           [0021]    The Z-plate  35  has a disc shape to make the outer circumference of the Z-plate  35  slide-contact with the inner circumference of the cylinder  50  in the view of plane projection and formed as a sinuous cam surface having the same thickness from the inner circumference to the outer circumference in the view of side projection. Therefore, a surface of a top dead center is contacted to the bottom surface of the first bearing plate  40  and is rotated, and a surface of a bottom dead center is tightly contacted to the upper surface of the second bearing plate  60  and is rotated.  
           [0022]    The first and the second vanes  38 ,  39  have a square plate shape and tightly contact to the sinuous cam surface of the Z plate  35  in the compression spaces V 1 , V 2  of the cylinder assembly  31 . When the Z-plate  35  rotates in the compression space of the cylinder assembly  31 , the first and the second vanes  38 ,  39  respectively divide the compression spaces V 1 , V 2  into a suction region and a compression region while performing a reciprocating motion up and down according to high and low of the cam surface of the Z-plate  35 .  
           [0023]    In addition, the first and the second vanes  38 ,  39  are elastically supported by the elastic supporting member  90  installed at the first and the second bearing plates  40 ,  60  respectively.  
           [0024]    The operation process of the conventional Z-compressor will be described.  
           [0025]    First, when the rotational shaft  24  is rotated by the driving force of the motor part  20 , the Z-plate  35  combined with the rotational shaft  24  in the cylinder assembly  31  is rotated simultaneously, and the gas suction, compression and discharge operations are performed.  
           [0026]    In more detail, the first space V 1  placed at the upper portion of the Z-plate  35  is divided into the suction region and the compression region on the basis of the top dead center of the Z-plate  35  and the first vane  38 , the second space V 2  placed at the lower portion of the Z-plate  35  is divided into the suction region and the compression region on the basis of the bottom dead center of the Z-plate  35  and the second vane  39 . In that state, by the rotation of the Z-plate  35 , the top dead center and the bottom dead center of the Z-plate  35  are moved, and accordingly a volume of the suction region and the compression region of each space is varied.  
           [0027]    Herein, the first and the second vanes  38 ,  39  reciprocate oppositely with each other about the cam surface height of the Z-plate  35 .  
           [0028]    Accordingly, gas is simultaneously sucked into each suction region of the first and the second spaces V 1 , V 2  through the suction pipe  12  and the suction paths  52 ,  54  and is gradually compressed, when the top dead center or the bottom dead center of the Z-plate  35  reaches a discharge start point, the compressed gas is simultaneously discharged to outside of the cylinder assembly  31  through the discharge paths  46 ,  66  of each space V 1 , V 2 . Afterward, the gas is discharged to the outside through the discharge pipe  14  after passing the first and the second discharge mufflers  70 ,  80  and the sealed casing  10 .  
           [0029]    Herein, according to the rotation of the rational shaft  24 , by the oil feeder  28  installed at the oil path  27  formed at the lower end of the rotational shaft  24 , the oil contained in (at the bottom surface of) the sealed casing  10  is sucked up through the oil path  27 , is dispersed at the upper end of the rotational shaft  24  and is supplied to sliding parts.  
           [0030]    As described above, in the conventional Z-compressor, gas compressed and discharged from the compression part and oil dispersed from the upper end of the rotational shaft flow together.  
           [0031]    According to it, the oil is discharged to outside of the sealed casing together with compressed gas discharged from the compression part, because the discharged oil remains behind on the lower portion or a bend portion, etc. of  5  a pipe due to dropping pressure of gas while passing a cycle system, oil inside the sealed casing is gradually reduced. Accordingly, life-span of parts may be reduced due to dry abrasion on sliding parts by shortage of oil inside the sealed casing, and a performance of the compressor may be lowered due to increase of friction at sliding parts.  
         SUMMARY OF THE INVENTION  
         [0032]    In order to solve the above-mentioned problems, it is an object of the present invention to provide a compressor having an oil returning apparatus which is capable of preventing oil leakage to outside of a sealed casing with discharged gas.  
           [0033]    In order to achieve the above-mentioned object, in a compressor including a sealed casing respectively communicating with a suction pipe and a discharge pipe; a cylinder assembly disposed in the sealed casing and having a suction path and a discharge path; a Z-plate partitioning the internal space of the cylinder assembly into plural compression spaces and sucking, compressing and discharging gas while being rotated by a motor part; a vane contacted to the both surfaces of the Z-plate and partitioning each compression space into a suction region and a compression region while performing a reciprocating motion; and a discharge muffler covered the both sides of the cylinder assembly and lowering noise of discharged gas, a compressor includes at least one oil returning member installed on a discharge route between a discharge path of a cylinder assembly and a discharge pipe of a sealed casing in order to filter oil flowing with gas. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0034]    [0034]FIG. 1 is a longitudinal sectional view illustrating the conventional Z-compressor;  
         [0035]    [0035]FIG. 2 is a longitudinal sectional view illustrating a Z-compressor having an oil returning apparatus in accordance with a first embodiment of the present invention;  
         [0036]    [0036]FIG. 3 is a partial sectional view illustrating part of an upper portion of a Z-compressor having an oil returning apparatus in accordance with a second embodiment of the present invention;  
         [0037]    [0037]FIG. 4 is a longitudinal sectional view illustrating major part of a Z-compressor having an oil returning apparatus in accordance with a third embodiment of the present invention; and  
         [0038]    [0038]FIG. 5 is a longitudinal sectional view illustrating major part of a Z-compressor having an oil returning apparatus in accordance with a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]    Hereinafter, the preferred embodiments of the present invention will be described with reference to accompanying drawings.  
         [0040]    In the meantime, in description of the preferred embodiments of the present invention, in order to compare with the conventional Z-compressor, the present invention will be described on the basis of a Z-compressor, however, the 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.  
         [0041]    A Z-compressor in accordance with a first embodiment of the present invention will be described with reference to accompanying FIG. 2.  
         [0042]    [0042]FIG. 2 is a longitudinal sectional view illustrating the Z-compressor in accordance with the first embodiment of the present invention.  
         [0043]    The Z-compressor in accordance with the first embodiment of the present invention includes a sealed casing  110 ; a motor part  120  disposed in the sealed casing  110  and generating a rotational force; and a compression part  130  for sucking, compressing and discharging gas by the rotational force generated in the motor part  120 .  
         [0044]    The side surface of the sealed casing  110  communicates with a suction pipe  112  for sucking gas, the upper portion of the sealed casing  110  communicates with a discharge pipe  114  for discharging compressed gas; and the bottom surface of the sealed casing  110  is filled with oil for lubricating sliding portions and cooling a heat generating portion of the sealed casing  110 .  
         [0045]    The motor part  120  consists of a stator  122  and a rotor  123  as a general electric motor.  
         [0046]    The compression part  130  includes a cylinder assembly  131  installed inside the sealed casing  110  and forming a compression space at which gas sucked from the outside is compressed; a rotational shaft  124  for transmitting a rotational force generated in the rotor  123  of the motor part  120 ; a Z-plate  135  rotatably combined with the rotational shaft  124  and partitioning the compression space of the cylinder assembly  131  into a first space V 1  and a second space V 2 ; a first and a second vanes  138 , 139  respectively contacted to the upper surface and the lower surface of the Z-plate  135  and partitioning each space V 1 , V 2  into a suction region and a compression region when the Z-plate  135  is rotated; and a first and a second discharge mufflers  170 ,  180  respectively covered the both sides of the cylinder assembly  131  and lowering noise of compression gas propagated from the discharge path of the cylinder assembly  131 .  
         [0047]    The Z-compressor in accordance with the present invention has the same/similar construction with/to the conventional Z-compressor.  
         [0048]    However, in the Z-compressor in accordance with the present invention, an oil returning member  200  is installed at a portion abutting on the discharge pipe  114  in order to filter oil flowing together with discharge gas.  
         [0049]    In order to pass discharge gas and filter oil, the oil returning member  200  has a screen shape having a certain mesh and a thickness, and the outer circumference of the oil returning member  200  is tightly contacted to the inner circumference of the sealed casing  110  by a welding method, etc.  
         [0050]    In the meantime, the oil returning member  200  can be fixed to the sealed casing  110  by using an additional supporting member.  
         [0051]    In addition, it is preferable for the oil returning member  200  to have a size corresponded to the inner circumference of the sealed casing  110  so as to be tightly contacted to the inner circumference of the sealed casing  110 .  
         [0052]    The operation of the Z-compressor in accordance with the first embodiment of the present invention will be described.  
         [0053]    First, when the rotational shaft  124  is rotated by the driving force of the motor part  120 , the Z-plate  135  combined with the rotational shaft  124  inside the cylinder assembly  131  is simultaneously rotated, and accordingly the operation for sucking, compressing and discharging gas is performed.  
         [0054]    In more detail, the first space V 1  placed at the upper portion of the Z-plate  135  is divided into the suction region and the compression region on the basis of the top dead center of the Z-plate  135  and the first vane  138 , and the second space V 2  placed at the lower portion of the Z-plate  135  is divided into the suction region and the compression region on the basis of the bottom dead center of the Z-plate  135  and the second vane  139 . In that state, by the rotation of the Z-plate  135 , the top dead center and the bottom dead center of the Z-plate  35  are moved, and accordingly a volume of the suction region and the compression region is varied.  
         [0055]    Herein, the first and the second vanes  138 ,  139  reciprocate oppositely with each other about the cam surface of the Z-plate  135 .  
         [0056]    Accordingly, gas is simultaneously sucked into each suction region of the first and the second spaces V 1 , V 2  through the suction pipe  112  and the suction paths  152 ,  154  and is gradually compressed, when the top dead center or the bottom dead center of the Z-plate  135  reaches a discharge start point, the compressed gas is simultaneously discharged to outside of the cylinder assembly  131  through the discharge paths  146 ,  166  of each space V 1 , V 2 . Afterward, the gas is discharged to the outside through the discharge pipe  114  after passing the first and the second discharge mufflers  170 ,  180  and the sealed casing  110 .  
         [0057]    And, according to the rotation of the rational shaft  124 , by the oil feeder  128  installed at the oil path  127  formed at the lower end of the rotational shaft  124 , the oil contained in (at the bottom surface of) the sealed casing  110  is sucked up through the oil path  127 , is dispersed at the upper end of the rotational shaft  124  and is supplied to sliding parts.  
         [0058]    Herein, the compression gas discharged through the discharge paths  146 , 166  of the cylinder assembly  131  is moved toward the discharge pipe  114  with oil, however, although the compressed gas passes the screen-shaped oil returning member  200  formed at the inlet of the discharge pipe  114  and is discharged to outside of the sealed casing  110  through the discharge pipe  114 , the oil is filtered by the oil returning member  200  and is returned to the sealed casing  110 . And, the returned oil lubricates the sliding parts of the sealed casing  110 .  
         [0059]    In the Z-compressor in accordance with the first embodiment of the present invention, by including a screen-shaped oil returning member formed at an inlet of a discharge pipe, compression gas passes as it is, on the contrary, oil flowing with the compression gas is returned into a sealed casing, and accordingly dry abrasion at sliding portions due to shortage of oil inside the sealed casing can be prevented.  
         [0060]    A compressor having an oil returning apparatus in accordance with a second embodiment of the present invention will be described with reference to accompanying FIG. 3. Hereinafter, the same parts with the parts of the Z-compressor in accordance with the first embodiment will have the same reference numerals, and detailed description will be abridged.  
         [0061]    [0061]FIG. 3 is a partial-longitudinal sectional view illustrating a discharge pipe of the Z-compressor in accordance with the second embodiment of the present invention.  
         [0062]    In the Z-compressor in accordance with the second embodiment of the present invention, an oil returning member  210  is inserted into and fixed at the inlet side of the discharge pipe  114  formed at the upper end of the sealed casing  110  so as to communicate with the casing  110 .  
         [0063]    The oil returning member  210  has a diameter corresponded to the inner diameter of the discharge pipe  114 , is tightly inserted into the discharge pipe  114  by a welding or a press-fitting method, etc. and has a screen shape so as to pass discharged compression gas and filter oil flowing with the compression gas.  
         [0064]    In the Z-compressor in accordance with the second embodiment of the present invention, by fixedly inserting the screen-shaped oil returning member into the discharge pipe, it is possible to prevent dry abrasion due to shortage of oil at a sliding portion inside the sealed casing by returning oil flowing with compression gas into the sealed casing. In addition, the oil returning member can be easily fabricated and fixed, and because it has a simple structure, a production cost can be reduced.  
         [0065]    A Z-compressor having an oil returning apparatus in accordance with a third embodiment of the present invention will be described with reference to accompanying FIG. 4. Hereinafter, the same parts with the parts of the Z-compressor in accordance with the first and second embodiments will have the same reference numerals, and detailed description will be abridged.  
         [0066]    [0066]FIG. 4 is a longitudinal sectional view illustrating major parts of the Z-compressor in accordance with the third embodiment of the present invention.  
         [0067]    In the Z-compressor in accordance with the third embodiment of the present invention, an oil returning member  220  is fixed between discharge paths  146 ,  166  respectively formed at the first and the second bearing plates  140 ,  160  and outlets  1   72 ,  1   82  of the first and the second discharge mufflers  170 ,  180 .  
         [0068]    The oil returning member  220  has a screen shape having a certain mesh to filter oil flowing with discharge gas.  
         [0069]    Herein, the oil returning member  220  has a disc shape. In more detail, the exterior of the oil returning member  220  is tightly contacted to the inner circumference of the first and the second discharge mufflers  170 ,  180  respectively covering the upper and the lower portions of the cylinder assembly  131  to lower noise of discharged gas by a welding method, etc., and the interior of the oil returning member  220  is tightly contacted to the outer circumference of the journal portions  144 , 164  of the first and the second bearing plates  240 ,  260 .  
         [0070]    Accordingly, the compression gas discharged from the discharge path  146 , 166  of the cylinder assembly  131  passes the oil returning member  220  and is charged through the outlets  172 ,  182  of the discharge mufflers  170 ,  180 , on the contrary, oil inside the discharge mufflers  170 ,  180  is filtered by the oil returning member  220 .  
         [0071]    Accordingly, oil filtered by the oil returning member  220  is returned into the discharge mufflers  170 , 180  and lubricates sliding portions of the vanes  138 ,  139  and the vane slots  142 , 162 , etc.  
         [0072]    In the Z-compressor in accordance with the third embodiment of the present invention, by installing an oil returning member inside a discharge muffler, compression gas passes as it is, on the contrary, oil flowing with the compression gas is returned into the discharge muffler, and accordingly dry abrasion at sliding portions due to shortage of oil inside the discharge muffler can be prevented.  
         [0073]    A Z-compressor having an oil returning apparatus in accordance with a fourth embodiment of the present invention will be described with reference to accompanying FIG. 5. Hereinafter, the same parts with the parts of the Z-compressor in accordance with the first, second and third embodiments will have the same reference numerals, and detailed description will be abridged.  
         [0074]    [0074]FIG. 5 is a longitudinal sectional view illustrating major parts of the Z-compressor in accordance with the fourth embodiment of the present invention.  
         [0075]    As depicted in FIG. 5, in the Z-compressor in accordance with the fourth embodiment of the present invention, an oil returning member  230  is inserted into the outlet  172  of the first and the second discharge mufflers  170 ,  180 .  
         [0076]    The oil returning member  230  is formed as a screen shape having a certain mesh so as to filter oil flowing with discharged gas.  
         [0077]    Accordingly, the compressed gas discharged from a discharge path  146 ,  166  of the cylinder assembly  131  is discharged through the oil returning member  230  inserted into the outlets  172 ,  182  of the discharge mufflers  170 ,  180 , on the contrary, oil is filtered by the oil returning member  230 , is returned into the discharge mufflers  1   70 ,  1   80  and lubricates sliding portions of the vanes  138 ,  139  and the vane slots  142 ,  162 , etc.  
         [0078]    In the Z-compressor in accordance with the fourth embodiment of the present invention, by inserting-installing an oil returning member inside an outlet of a discharge muffler, compression gas passes as it is, on the contrary, oil flowing with the compression gas is returned into the discharge muffler, and accordingly dry abrasion at sliding portions due to shortage of oil inside the discharge muffler can be prevented. In addition, the oil returning member can be easily fabricated and fixed.  
       Industrial Applicability  
       [0079]    In a Z-compressor in accordance with the present invention, by installing an oil returning member having a screen shape at a discharge route between a discharge path of a cylinder assembly and a discharge pipe of a sealed casing, oil flowing with discharged compression gas can be returned, and accordingly dry abrasion due to shortage of oil at sliding portions inside the sealed casing can be prevented.  
         [0080]    The oil returning member in accordance with the present invention can be applied to a reciprocating compressor, a scroll compressor, a centrifugal compressor and a rotation compressor, etc. as well as a Z-compressor.