Abstract:
A compressor may include a housing and first and second scroll members supported within the housing, each having an end plate with a spiral wrap extending therefrom and meshingly engaged with the other to form a series of compression pockets operating at an intermediate fluid pressure between a suction pressure and a discharge pressure. A first passage in communication with one of the compression pockets extends from a first side of the first end plate to a second side of the first end plate generally opposite the first side. A modulation plate overlies the second side of the first scroll member for radial displacement between first and second positions. The modulation plate isolates the first passage from communication with a suction pressure region of the compressor when in the first position and provides communication between the first passage and the suction pressure region when in the second position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/057,425, filed on May 30, 2008. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to compressors, and more specifically to compressors having capacity modulation systems. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    Scroll compressors include a variety of capacity modulation mechanisms to vary operating capacity of a compressor. The capacity modulation mechanisms may include fluid passages extending through a scroll member to selectively provide fluid communication between compression pockets and another pressure region of the compressor. 
       SUMMARY 
       [0005]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0006]    A compressor may include a housing and first scroll member supported within the housing and having a first end plate with a first spiral wrap extending from a first side of the first end plate. The second scroll member may be supported within the housing and may include a second end plate having a second spiral wrap extending therefrom and meshingly engaged with the first spiral wrap to form a series of compression pockets operating at an intermediate fluid pressure between a suction pressure and a discharge pressure. A first passage may be in communication with one of the compression pockets and extend from the first side of the first end plate to a second side of the first end plate generally opposite the first side. The modulation plate may overly the second side of the first scroll member and be secured within the housing for radial displacement between first and second positions. The modulation plate may isolate the first passage from communication with a suction pressure region of the compressor when in the first position and provide communication between the first passage and the suction pressure region when in the second position. 
         [0007]    The compressor modulation plate may slide along the second side of the first end plate during displacement from the first position to the second position. 
         [0008]    The compressor modulation plate may be pivotally coupled within the housing to a structure that is fixed relative to the first scroll member. 
         [0009]    The compressor modulation plate may be pivotally coupled to the first scroll member. 
         [0010]    The compressor may include an actuation mechanism engaged with the modulation plate to displace the modulation plate between the first and second positions. 
         [0011]    The compressor may include a first scroll member defining a first recess housing the modulation plate therein and being in communication with the first passage and the suction pressure region. 
         [0012]    The compressor may include a seal assembly engaged with the housing and isolating the suction pressure region of the compressor from a discharge pressure region of the compressor. A seal assembly and the first scroll member may define a second recess. 
         [0013]    The compressor may include a first recess that is isolated from the second recess. 
         [0014]    The compressor may include a first recess that is located axially between the second side of the first end plate and the second recess. 
         [0015]    The compressor modulation plate may include an aperture in communication with the first passage when the modulation plate is in the first position. 
         [0016]    The compressor modulation plate may include first and second surfaces generally opposite one another. A first surface may have a recess extending therein and defining a first radial surface area. The aperture may extend through the first and second surfaces and provide communication between the recess and the first passage when the modulation plate is in the first position. A second surface may define a second radial surface area exposed to the first passage when the modulation plate is in the first position. The second radial surface area may be approximately equal to the first radial surface area. 
         [0017]    The compressor may include a recess that includes a seal to prevent communication between the suction pressure region and the recess when the modulation plate is in the first position. 
         [0018]    The compressor may include a spring disposed within the recess of the modulation plate to axially bias the seal against the first scroll member. 
         [0019]    The compressor may include a first passage that has a generally arcuate shape having an angular extent of at least twenty degrees. 
         [0020]    A compressor may include a housing and a first scroll member supported within the housing and having a first end plate with a first spiral wrap extending from a first side of said first end plate. A second scroll member may be supported within the housing and include a second end plate having a second spiral wrap extending therefrom and meshingly engaged with the first spiral wrap to form a series of compression pockets operating at an intermediate fluid pressure between a suction pressure and a discharge pressure. A first passage may be in communication with one of the compressor pockets and extend from the first side of the first end plate to a second side of the first end plate generally opposite the first side. The seal assembly may be engaged with the housing and the first scroll member and define an axial biasing chamber in communication with a first of the compression pockets. The modulation plate may overly the second side of the first scroll member and be located axially between the axial biasing chamber and the compression pockets and within an outer perimeter of the axial biasing chamber. The modulation plate may be secured within the housing for radial displacement between the first and second positions. The modulation plate may isolate the first passage from communication with a suction pressure region of the compressor when in the first position and provide communication between the first passage and the suction pressure region when in the second position. 
         [0021]    The compressor modulation plate may include an annular body defining a central opening and the first scroll member includes an annular hub extending through the central opening. 
         [0022]    The compressor modulation plate may include a pivot mount having a pivot pin extending therethrough and pivotally coupling the modulation plate within the housing to a structure that is fixed relative to the first scroll member. 
         [0023]    The compressor may include of an actuation mechanism. The modulation plate may include an arm extending radially outward from the annular body and coupled to the actuation mechanism. 
         [0024]    The compressor actuation mechanism may pivot the modulation plate about the pivot pin. 
         [0025]    The compressor modulation plate may slide along the second side of the first end plate during displacement from the first position to the second position. 
         [0026]    The compressor modulation plate may include an aperture in communication with the first passage when the modulation plate is in the first position. 
         [0027]    The compressor modulation plate may include a first and second surface generally opposite one another. The first surface may have a recess extending therein and defining a first radial surface area. The aperture may extend through the first and second surfaces and provide communication between the recess and the first passage when the modulation plate is in the first position. The second surface may define a second radial surface area exposed to the first passage when the modulation plate is in the first position. The second radial surface area may be approximately equal to the first radial surface area. 
         [0028]    The compressor recess may include a seal to prevent communication between the suction pressure region and the recess when the modulation plate is in the first position. 
         [0029]    The compressor may include a spring disposed within the recess of the modulation plate to axially bias the seal against the first scroll member. 
         [0030]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0031]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0032]      FIG. 1  is a section view of a compressor according to the present disclosure; 
           [0033]      FIG. 2  is a plan view of a non-orbiting scroll member of the compressor of  FIG. 1 ; 
           [0034]      FIG. 3  is a section view of a non-orbiting scroll, seal assembly, and modulation system of the compressor of  FIG. 1 ; 
           [0035]      FIG. 4  is an additional section view of the non-orbiting scroll, seal assembly, and modulation system of  FIG. 3 ; 
           [0036]      FIG. 5  is a section view of an alternate non-orbiting scroll, seal assembly, and modulation system according to the present disclosure; 
           [0037]      FIG. 6  is a plan view of the non-orbiting scroll and modulation system of  FIG. 3 ; 
           [0038]      FIG. 7  is an additional plan view of the non-orbiting scroll and modulation system of  FIG. 6 ; and 
           [0039]      FIG. 8  is a plan view of a portion of the modulation system of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0041]    The present teachings are suitable for incorporation in many different types of scroll and rotary compressors, including hermetic machines, open drive machines and non-hermetic machines. For exemplary purposes, a compressor  10  is shown as a hermetic scroll refrigerant-compressor of the low-side type, i.e., where the motor and compressor are cooled by suction gas in the hermetic shell, as illustrated in the vertical section shown in  FIG. 1 . 
         [0042]    With reference to  FIG. 1 , compressor  10  may include a hermetic shell assembly  12 , a main bearing housing assembly  14 , a motor assembly  16 , a compression mechanism  18 , a seal assembly  20 , a refrigerant discharge fitting  22 , a discharge valve assembly  24 , a suction gas inlet fitting  26 , and a modulation assembly  27 . Shell assembly  12  may house main bearing housing assembly  14 , motor assembly  16 , and compression mechanism  18 . 
         [0043]    Shell assembly  12  may generally form a compressor housing and may include a cylindrical shell  28 , an end cap  30  at the upper end thereof, a transversely extending partition  32 , and a base  34  at a lower end thereof. End cap  30  and partition  32  may generally define a discharge chamber  36 . Discharge chamber  36  may generally form a discharge muffler for compressor  10 . Refrigerant discharge fitting  22  may be attached to shell assembly  12  at opening  38  in end cap  30 . Discharge valve assembly  24  may be located within discharge fitting  22  and may generally prevent a reverse flow condition. Suction gas inlet fitting  26  may be attached to shell assembly  12  at opening  40 . Partition  32  may include a discharge passage  46  therethrough providing communication between compression mechanism  18  and discharge chamber  36 . 
         [0044]    Main bearing housing assembly  14  may be affixed to shell  28  at a plurality of points in any desirable manner, such as staking. Main bearing housing assembly  14  may include a main bearing housing  52 , a first bearing  54  disposed therein, bushings  55 , and fasteners  57 . Main bearing housing  52  may include a central body portion  56  having a series of arms  58  extending radially outwardly therefrom. Central body portion  56  may include first and second portions  60 ,  62  having an opening  64  extending therethrough. Second portion  62  may house first bearing  54  therein. First portion  60  may define an annular flat thrust bearing surface  66  on an axial end surface thereof. Arms  58  may include apertures  70  extending therethrough and receiving fasteners  57 . 
         [0045]    Motor assembly  16  may generally include a motor stator  76 , a rotor  78 , and a drive shaft  80 . Windings  82  may pass through stator  76 . Motor stator  76  may be press fit into shell  28 . Drive shaft  80  may be rotatably driven by rotor  78 . Rotor  78  may be press fit on drive shaft  80 . Drive shaft  80  may include an eccentric crank pin  84  having a flat  86  thereon. 
         [0046]    Compression mechanism  18  may generally include an orbiting scroll  104  and a non-orbiting scroll  106 . Orbiting scroll  104  may include an end plate  108  having a spiral vane or wrap  110  on the upper surface thereof and an annular flat thrust surface  112  on the lower surface. Thrust surface  112  may interface with annular flat thrust bearing surface  66  on main bearing housing  52 . A cylindrical hub  114  may project downwardly from thrust surface  112  and may have a drive bushing  116  rotatively disposed therein. Drive bushing  116  may include an inner bore in which crank pin  84  is drivingly disposed. Crank pin flat  86  may drivingly engage a flat surface in a portion of the inner bore of drive bushing  116  to provide a radially compliant driving arrangement. An Oldham coupling  117  may be engaged with the orbiting and non-orbiting scrolls  104 ,  106  to prevent relative rotation therebetween. 
         [0047]    With additional reference to  FIGS. 2-4 ,  6  and  7 , non-orbiting scroll  106  may include an end plate  118  having a spiral wrap  120  on a lower surface thereof, a series of radially outwardly extending flanged portions  121 , and a plate member  123 . Spiral wrap  120  may form a meshing engagement with wrap  110  of orbiting scroll  104 , thereby creating a series of pockets  122 ,  124 ,  126 ,  128 ,  130 ,  132 . Non-orbiting scroll  106  may be axially displaceable relative to main bearing housing assembly  14 , shell assembly  12 , and orbiting scroll  104 . Non-orbiting scroll  106  may include a discharge passage  134  in communication with pocket  132  and in fluid communication with discharge chamber  36  via discharge passage  46  in partition  32 . 
         [0048]    Flanged portions  121  may include openings  137  therethrough. Opening  137  may receive bushings  55  therein and bushings  55  may receive fasteners  57 . Fasteners  57  may be engaged with main bearing housing  52  and bushings  55  may generally form a guide for axial displacement of non-orbiting scroll  106 . Fasteners  57  may additionally prevent rotation of non-orbiting scroll  106  relative to main bearing housing assembly  14 . 
         [0049]    End plate  118  may include an inner side wall  140  defining an annular hub surrounding discharge passage  134 . Plate member  123  may include an outer side wall  142  generally parallel to and coaxial with inner side wall  140 . Plate member  123  may be fixed to end plate  118  and may cooperate with end plate  118  to form first and second annular recesses  144 ,  146 . As seen in  FIGS. 6 and 7 , plate member  123  may include openings  148 ,  150 ,  152  through outer side wall  142  providing communication between second annular recess  146  and a suction pressure region of compressor  10 . 
         [0050]    First and second annular recesses  144 ,  146  may be isolated from one another. First annular recess  144  may provide for axial biasing of non-orbiting scroll  106  relative to orbiting scroll  104 . More specifically, a passage  154  may extend through end plate  118  of non-orbiting scroll  106 , placing first annular recess  144  in fluid communication with one of pockets  122 ,  124 ,  126 ,  128 ,  130  operating at an intermediate fluid pressure. Additional passages  156 ,  158  may extend through end plate  118 , placing second annular recess  146  in communication with two or more of pockets  122 ,  124 ,  126 ,  128 ,  130  operating at an intermediate fluid pressure. Passages  156 ,  158  may have an arcuate form having an angular extent of at least twenty degrees. Second annular recess  146  may be in communication with different ones of pockets  122 ,  124 ,  126 ,  128 ,  130  than first annular recess  144 . More specifically, second annular recess  146  may be in communication with two or more of pockets  122 ,  124 ,  126 ,  128 ,  130  located radially outwardly relative to the pocket  122 ,  124 ,  126 ,  128 ,  130  in communication with the first annular recess  144 . Therefore, first annular recess  144  may operate at a pressure greater than an operating pressure of second annular recess  146 . 
         [0051]    Seal assembly  20  may include a floating seal located within first annular recess  144  forming an axial biasing chamber. Seal assembly  20  may be axially displaceable relative to shell assembly  12  and non-orbiting scroll  106  to provide for axial displacement of non-orbiting scroll  106  while maintaining a sealed engagement with partition  32  to isolate discharge and suction pressure regions of compressor  10  from one another. More specifically, pressure within first annular recess  144  may bias seal assembly  20  into engagement with partition  32  during normal compressor operation. 
         [0052]    Modulation assembly  27  may include a modulation plate assembly  160  and an actuation mechanism  162 . Modulation plate assembly  160  may include a modulation plate  164 , first and second seals  166 ,  168 , and a pivot pin  170 . With additional reference to  FIG. 8 , modulation plate  164  may include a generally circular main body  172  defining a central opening  173  and having a pivot mount  174  and an arm  176  extending radially outward therefrom, and a series of protrusions  178 ,  180 ,  182  extending axially outward from a lower surface thereof. Inner side wall (or annular hub)  140  may extend through central opening  173 . Protrusions  178 ,  180  may have a shape generally conforming to the shape of passages  156 ,  158 , but having a greater width and angular extent than passages  156 ,  158 . First and second recesses  184 ,  186  may extend axially into an upper surface of main body  172  at a location above a portion of first and second protrusions  178 ,  180 . 
         [0053]    A first aperture  192  may be located in first recess  184  and extend through protrusion  178  and a second aperture  194  may be located in second recess  186  and may extend through second protrusion  180 . First seal  166  may be located within first recess  184  and second seal  168  may be located within second recess  186 . As seen in  FIGS. 3 and 4 , first and second seals  166 ,  168  may have generally annular bodies. Additionally, biasing members  169  may be engaged with first and second seals  166 ,  168  to urge first and second seals  166 ,  168  into engagement with plate member  123  and isolate first and second recesses  184 ,  186  from the suction pressure region of compressor  10 . 
         [0054]    Alternatively, as seen in  FIG. 5 , first and second seals  166 ,  168  may be replaced with seal  266 . Seal  266  may include an axial extending portion  268  and a radially extending portion  270 . Axial extending portion  268  may be engaged with modulation plate  264  and radially extending portion  270  may be engaged with plate member  223 . Biasing members  269  may be engaged with modulation plate  264  and radially extending portion  270  to bias seal  266  against plate member  223 . 
         [0055]    Referring back to  FIGS. 3 ,  4 ,  6  and  7 , modulation plate  164  may overly an upper surface of end plate  118  and may be pivotally coupled within shell assembly  12  at pivot mount  174 . Pivot pin  170  may extend through pivot mount  174  and may be fixed relative to non-orbiting scroll  106 . More specifically, pivot pin  170  may extend into end plate  118  of non-orbiting scroll  106  and be fixed thereto. As such, modulation plate  164  may be slidable along the upper surface of end plate  118 . The upper surface of end plate  118  may generally form an axial end surface of modulation plate  164 . 
         [0056]    Actuation mechanism  162  may be coupled to arm  176  of modulation plate  164  and may displace modulation plate  164  between first and second positions. Actuation mechanism  162  may form a linear actuator. The displacement between the first and second positions may include modulation plate  164  being slid radially along the upper surface of end plate  118 . 
         [0057]    In the first position ( FIGS. 3 and 6 ), protrusion  178  may overly and seal passage  156  and protrusion  180  may overly and seal passage  158 , isolating passages  156 ,  158  from communication with the suction pressure region of compressor  10 . When modulation plate  164  is in the first position, first aperture  192  may provide communication between passage  156  and first recess  184  and second aperture  194  may provide communication between passage  158  and second recess  186 . As indicated above, first and second seals  166 ,  168  may isolate first and second recesses  184 ,  186  from communication with the suction pressure region. First and second recesses  184 ,  186  may be sized to balance a force applied to protrusions  178 ,  180  of modulation plate  164  by the pressurized fluid from passages  156 ,  158 . 
         [0058]    For simplicity, first recess  184  and protrusion  178  will be discussed with the understanding that the description applies equally to second recess  186  and protrusion  180 . Protrusion  178  may have a lower axial surface  196  exposed to passage  156  and first recess  184  may include an upper axial surface  198  exposed to pressurized fluid within first recess  184  provided by passage  156 . Therefore, the pressure applied to upper and lower axial surfaces  196 ,  198  may be generally the same. Lower axial surface  196  may have a first radially extending surface area exposed to the pressurized fluid from passage  156  and upper axial surface  198  may have a second radially extending surface area exposed to the pressurized fluid. The first and second radially extending surface areas may be generally similar to one another, balancing the axial force applied on modulation plate  164  from the pressurized fluid and the axial force applied to modulation plate  164  by biasing members  169 . 
         [0059]    In the second position ( FIGS. 4 and 7 ), protrusions  178 ,  180  may be displaced radially from passages  156 ,  158 , providing communication between passages  156 ,  158  and the suction pressure region of compressor  10  via openings  148 ,  150 ,  152 . When modulation plate  164  is in the second position, capacity of compressor  10  may be reduced relative to the capacity of compressor  10  when modulation plate  164  is in the first position. 
         [0060]    The terms “first”, “second”, etc. are used throughout the description for clarity only and are not intended to limit similar terms in the claims.