Patent Publication Number: US-11022119-B2

Title: Variable volume ratio compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/567,277, filed on Oct. 3, 2017. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a variable volume ratio compressor. 
     BACKGROUND 
     This section provides background information related to the present disclosure and is not necessarily prior art. 
     Compressors are used in a variety of industrial, commercial and residential applications to circulate a working fluid within a climate-control system (e.g., a refrigeration system, an air conditioning system, a heat-pump system, a chiller system, etc.) to provide a desired cooling and/or heating effect. A typical climate-control system may include a fluid circuit having an outdoor heat exchanger, an indoor heat exchanger, an expansion device disposed between the indoor and outdoor heat exchangers, and a compressor circulating a working fluid (e.g., refrigerant or carbon dioxide) between the indoor and outdoor heat exchangers. Efficient and reliable operation of the compressor is desirable to ensure that the climate-control system in which the compressor is installed is capable of effectively and efficiently providing a cooling and/or heating effect on demand. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     The present disclosure provides a compressor that may include a shell assembly, a non-orbiting scroll, an orbiting scroll, and variable-volume-ratio valve assembly. The shell assembly may define a discharge chamber. The non-orbiting scroll may be disposed within the discharge chamber and may include a first end plate and a first spiral wrap extending from the first end plate. The orbiting scroll may be disposed within the discharge chamber and may include a second end plate and a second spiral wrap extending from the second end plate. The first and second spiral wraps mesh with each other to define a plurality of fluid pockets therebetween. The fluid pockets are movable among a radially outermost position, a radially intermediate position, and a radially innermost position. The second end plate may include a variable-volume-ratio port extending therethrough and selectively communicating with one of the fluid pockets at the radially intermediate position. The variable-volume-ratio valve assembly may be mounted to the orbiting scroll and may include a valve member that is movable relative to the orbiting scroll between an open position allowing communication between the variable-volume-ratio port and the discharge chamber and a closed position restricting communication between the variable-volume-ratio port and the discharge chamber. 
     In some configurations of the compressor of the above paragraph, when the valve member is in the open position, fluid flows from the variable-volume-ratio port to the discharge chamber without flowing back into any of the fluid pockets. 
     In some configurations of the compressor of either of the above paragraphs, the first end plate of the non-orbiting scroll includes a discharge passage in communication with the discharge chamber and one of the fluid pockets at the radially innermost position. The variable-volume-ratio port is disposed radially outward relative to the discharge passage. 
     In some configurations of the compressor of any one or more of the above paragraphs, when the valve member is in the open position, fluid flows from the variable-volume-ratio port to the discharge chamber without flowing through the discharge passage in the non-orbiting scroll. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an annular hub extending from a side of the second end plate opposite the second spiral wrap. The annular hub may define a cavity in which the variable-volume-ratio valve assembly is at least partially disposed. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a driveshaft engaging the annular hub and driving the orbiting scroll. 
     In some configurations of the compressor of any one or more of the above paragraphs, the driveshaft includes a crank pin disposed within the cavity. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a bearing disposed within the cavity and receiving the crank pin. The bearing may at least partially define a flow path extending from the variable-volume-ratio port to the discharge chamber. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a bearing disposed within the cavity and receiving the crank pin. The annular hub includes a flow passage extending therethrough. The flow passage may be disposed radially outward relative to the bearing and at least partially defines a flow path extending from the variable-volume-ratio port to the discharge chamber. 
     In some configurations of the compressor of any one or more of the above paragraphs, the annular hub is a two-piece hub including a first annular member and a second annular member. The second annular member may be at least partially received within the first annular member and may receive the bearing. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a retainer disposed within the cavity and fixedly mounted to the second end plate. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is a reed valve that is sandwiched between the retainer and the second end plate. The reed valve may bend between the open and closed positions. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes another variable-volume-ratio port. The valve member may selectively open and close the variable-volume-ratio ports. The valve member may be fixedly attached to the second end plate at a location radially between the variable-volume-ratio ports. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes a recess disposed between and in communication with the variable-volume-ratio port and the cavity. The valve member may be disposed within the recess and may be movable therein between the open and closed positions. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a spring disposed at least partially within the recess and between the valve member and the retainer. The spring may bias the valve member toward the closed position. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is a disc-shaped member having a flow passage formed in its periphery. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an additional variable-volume-ratio port. The variable-volume-ratio valve assembly may include another spring and another valve member movably received within another recess that is in communication with the cavity and the additional variable-volume-ratio port. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an annular hub extending from a side of the second end plate opposite the second spiral wrap. The annular hub may define a cavity that receives a crank pin of a driveshaft. The annular hub may be a two-piece hub including a first annular member and a second annular member. The second annular member may be partially received within the first annular member and may receive the crank pin. The variable-volume-ratio valve assembly may be mounted to the second annular member. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a spring disposed between the second annular member and the valve member and biasing the valve member toward the closed position. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is a disc-shaped member having a flow passage formed in its periphery. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is disposed radially between the first and second annular members and extends partially around the crank pin of the driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio port extends through a portion of the first annular member. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member contacts an inner diametrical surface of the first annular member when the valve member is in the closed position. 
     In some configurations of the compressor of any one or more of the above paragraphs, a portion of the valve member moves inward away from the inner diametrical surface of the first annular member when the valve member moves from the closed position to the open position. 
     In some configurations of the compressor of any one or more of the above paragraphs, the orbiting scroll includes a first portion and a second portion attached to the first portion by a plurality of fasteners. The first portion may include the second spiral wrap and a portion of the second end plate. The second portion may include another portion of the second end plate and an annular hub that receives a crank pin of a driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the annular hub includes a flow passage in communication with the variable-volume-ratio port and the discharge chamber. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a spring disposed between the valve member and the second portion of the orbiting scroll. The spring may bias the valve member toward a valve seat defined by the first portion of the orbiting scroll. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a driveshaft having an eccentric recess. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an annular hub extending from a side of the second end plate opposite the second spiral wrap. 
     In some configurations of the compressor of any one or more of the above paragraphs, the annular hub defines a cavity in which the variable-volume-ratio valve assembly is at least partially disposed. 
     In some configurations of the compressor of any one or more of the above paragraphs, the annular hub is received within the eccentric recess of the driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the driveshaft includes a flow passage in fluid communication with the cavity. 
     In some configurations of the compressor of any one or more of the above paragraphs, when the valve member is in the open position, fluid from the variable-volume-ratio port flows into the cavity. 
     In some configurations of the compressor of any one or more of the above paragraphs, fluid in the cavity may flow into the discharge chamber via the flow passage in the driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the flow passage is disposed in a collar portion of the driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the collar portion is disposed at an axial end of the driveshaft and defines the eccentric recess. 
     The present disclosure also provides a compressor that may include a shell assembly, a first scroll, a second scroll, and variable-volume-ratio valve assembly. The shell assembly may define a discharge chamber. The first scroll may be disposed within the discharge chamber and may include a first end plate and a first spiral wrap extending from the first end plate. The first end plate may include a discharge passage in communication with the discharge chamber. The second scroll may be disposed within the discharge chamber and may include a second end plate and a second spiral wrap extending from the second end plate. The first and second spiral wraps mesh with each other to define a plurality of moving fluid pockets therebetween. The second end plate may include a variable-volume-ratio port disposed radially outward relative to the discharge passage and selectively communicating with one of the fluid pockets. The variable-volume-ratio valve assembly may be mounted to the second scroll and may include a valve member that is movable relative to the second scroll between an open position allowing communication between the variable-volume-ratio port and the discharge chamber and a closed position restricting communication between the variable-volume-ratio port and the discharge chamber. 
     In some configurations of the compressor of the above paragraph, the first scroll is a non-orbiting scroll, and the second scroll is an orbiting scroll. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an annular hub extending from a side of the second end plate opposite the second spiral wrap. The annular hub may define a cavity in which the variable-volume-ratio valve assembly is at least partially disposed. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a driveshaft engaging the annular hub and driving the orbiting scroll. 
     In some configurations of the compressor of any one or more of the above paragraphs, the driveshaft includes a crank pin disposed within the cavity. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a bearing disposed within the cavity and receiving the crank pin. The bearing may at least partially define a flow path extending from the variable-volume-ratio port to the discharge chamber. 
     In some configurations of the compressor of any one or more of the above paragraphs, the compressor includes a bearing disposed within the cavity and receiving the crank pin. The annular hub includes a flow passage extending therethrough. The flow passage may be disposed radially outward relative to the bearing and at least partially defines a flow path extending from the variable-volume-ratio port to the discharge chamber. 
     In some configurations of the compressor of any one or more of the above paragraphs, the annular hub is a two-piece hub including a first annular member and a second annular member. The second annular member may be at least partially received within the first annular member and may receive the bearing. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a retainer disposed within the cavity and fixedly mounted to the second end plate. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is a reed valve that is sandwiched between the retainer and the second end plate. The reed valve may bend between the open and closed positions. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes another variable-volume-ratio port. The valve member may selectively open and close the variable-volume-ratio ports. The valve member may be fixedly attached to the second end plate at a location radially between the variable-volume-ratio ports. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes a recess disposed between and in communication with the variable-volume-ratio port and the cavity. The valve member may be disposed within the recess and may be movable therein between the open and closed positions. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a spring disposed at least partially within the recess and between the valve member and the retainer. The spring may bias the valve member toward the closed position. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is a disc-shaped member having a flow passage formed in its periphery. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an additional variable-volume-ratio port. The variable-volume-ratio valve assembly may include another spring and another valve member movably received within another recess that is in communication with the cavity and the additional variable-volume-ratio port. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second end plate includes an annular hub extending from a side of the second end plate opposite the second spiral wrap. The annular hub may define a cavity that receives a crank pin of a driveshaft. The annular hub may be a two-piece hub including a first annular member and a second annular member. The second annular member may be partially received within the first annular member and may receive the crank pin. The variable-volume-ratio valve assembly may be mounted to the second annular member. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a spring disposed between the second annular member and the valve member and biasing the valve member toward the closed position. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is a disc-shaped member having a flow passage formed in its periphery. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member is disposed radially between the first and second annular members and extends partially around the crank pin of the driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio port extends through a portion of the first annular member. 
     In some configurations of the compressor of any one or more of the above paragraphs, the valve member contacts an inner diametrical surface of the first annular member when the valve member is in the closed position. 
     In some configurations of the compressor of any one or more of the above paragraphs, a portion of the valve member moves inward away from the inner diametrical surface of the first annular member when the valve member moves from the closed position to the open position. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second scroll includes a first portion and a second portion attached to the first portion by a plurality of fasteners. The first portion may include the second spiral wrap and a portion of the second end plate. The second portion may include another portion of the second end plate. 
     In some configurations of the compressor of any one or more of the above paragraphs, the second portion includes an annular hub that receives a crank pin of a driveshaft. 
     In some configurations of the compressor of any one or more of the above paragraphs, the annular hub includes a flow passage in communication with the variable-volume-ratio port and the discharge chamber. 
     In some configurations of the compressor of any one or more of the above paragraphs, the variable-volume-ratio valve assembly includes a spring disposed between the valve member and the second portion of the second scroll. The spring may bias the valve member toward a valve seat defined by the first portion of the second scroll. 
     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 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a cross-sectional view of a compressor having a variable-volume-ratio valve assembly according to the principles of the present disclosure; 
         FIG. 2  is a cross-sectional view of a compression mechanism and the variable-volume-ratio valve assembly of the compressor of  FIG. 1  with a valve member in a closed position; 
         FIG. 3  is a cross-sectional view of a compression mechanism and the variable-volume-ratio valve assembly of the compressor of  FIG. 1  with the valve member in an open position; 
         FIG. 4  is another cross-sectional view of a scroll of the compression mechanism and the variable-volume-ratio valve assembly; 
         FIG. 5  is a cross-sectional view of another configuration of a scroll another configuration of a variable-volume-ratio valve assembly according to the principles of the present disclosure; 
         FIG. 6  is another cross-sectional view of the scroll and variable-volume-ratio valve assembly of  FIG. 5 ; 
         FIG. 7  is a perspective view of a valve member of the variable-volume-ratio valve assembly of  FIG. 5 ; 
         FIG. 8  is a cross-sectional view of yet another configuration of a scroll and variable-volume-ratio valve assembly according to the principles of the present disclosure; 
         FIG. 9  is another cross-sectional view of the scroll and variable-volume-ratio valve assembly of  FIG. 8 ; 
         FIG. 10  is a cross-sectional view of yet another configuration of a scroll and variable-volume-ratio valve assembly according to the principles of the present disclosure; 
         FIG. 11  is another cross-sectional view of the scroll and variable-volume-ratio valve assembly of  FIG. 10 ; 
         FIG. 12  is a cross-sectional view of yet another configuration of a scroll and variable-volume-ratio valve assembly according to the principles of the present disclosure; 
         FIG. 13  is another cross-sectional view of the scroll and variable-volume-ratio valve assembly of  FIG. 12 ; 
         FIG. 14  is a cross-sectional view of yet another configuration of a scroll and variable-volume-ratio valve assembly according to the principles of the present disclosure; 
         FIG. 15  is a cross-sectional perspective view a portion of the scroll and the variable-volume-ratio valve assembly of  FIG. 14 ; 
         FIG. 16  is an exploded view of the variable-volume-ratio valve assembly of  FIG. 14 ; and 
         FIG. 17  is a cross-sectional view of another compressor having a variable-volume-ratio valve assembly according to the principles of the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
     Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     With reference to  FIGS. 1-4 , a compressor  10  is provided. The compressor  10  may be a high-side scroll compressor including a hermetic shell assembly  12 , a first and second bearing assemblies  14 ,  16 , a motor assembly  18 , a compression mechanism  20 , and a variable-volume-ratio (VVR) valve assembly  22 . As described in more detail below, the VVR valve assembly  22  is operable to prevent the compression mechanism  20  from over-compressing working fluid. 
     The shell assembly  12  may define a high-pressure discharge chamber  24  and may include a cylindrical shell  26 , an end cap  28  at an upper end thereof, and a base  30  at a lower end thereof. A discharge fitting  32  may be attached to the shell assembly  12  (e.g., at the end cap  28 ) and extend through a first opening in the shell assembly  12  to allow working fluid in the discharge chamber  24  to exit the compressor  10 . An inlet fitting  34  may be attached to the shell assembly  12  (e.g., at the end cap  28 ) and extend through a second opening in the shell assembly  12 . The inlet fitting  34  may extend through a portion of the discharge chamber  24  and is fluidly coupled to a suction inlet of the compression mechanism  20 . In this manner, the inlet fitting  34  provides low-pressure (suction-pressure) working fluid to the compression mechanism  20  while fluidly isolating the suction-pressure working fluid therein from the high-pressure (i.e., discharge-pressure) working fluid in the discharge chamber  24 . 
     The first and second bearing assemblies  14 ,  16  may be disposed entirely within the discharge chamber  24 . The first bearing assembly  14  may include a first bearing housing  36  and a first bearing  38 . The first bearing housing  36  may be fixed to the shell assembly  12 . The first bearing housing  36  houses the first bearing  38  and axially supports the compression mechanism  20 . The second bearing assembly  16  may include a second bearing housing  40  and a second bearing  42 . The second bearing housing  40  is fixed to the shell assembly  12  and supports the second bearing  42 . 
     The motor assembly  18  may be disposed entirely within the discharge chamber  24  and may include a motor stator  44 , a rotor  46 , and a driveshaft  48 . The stator  44  may be fixedly attached (e.g., by press fit) to the shell  26 . The rotor  46  may be press fit on the driveshaft  48  and may transmit rotational power to the driveshaft  48 . The driveshaft  48  may include a main body  50  and an eccentric crank pin  52  extending from an end of the main body  50 . The main body  50  is received in the first and second bearings  38 ,  42  and is rotatably supported by the first and second bearing assemblies  14 ,  16 . Therefore, the first and second bearings  38 ,  42  define a rotational axis of the driveshaft  48 . The crank pin  52  may engage the compression mechanism  20 . 
     The compression mechanism  20  may be disposed entirely within the discharge chamber  24  and may include an orbiting scroll  54  and a non-orbiting scroll  56 . The orbiting scroll  54  may include an end plate  58  having a spiral wrap  60  extending therefrom. An annular hub  62  may project downwardly from the end plate  58  and may include a cavity  63  in which a drive bearing  64 , a drive bushing  66  and the crank pin  52  may be disposed. The drive bushing  66  may be received within the drive bearing  64 . The crank pin  52  may be received within the drive bushing  66 . An Oldham coupling  68  may be engaged with the end plate  58  and either the non-orbiting scroll  56  or the first bearing housing  36  to prevent relative rotation between the orbiting and non-orbiting scrolls  54 ,  56 . The annular hub  62  may be axially supported by a thrust surface  70  of the first bearing housing  36 . The annular hub  62  may movably engage a seal  72  attached to the first bearing housing  36  to define an intermediate-pressure cavity  73  between the first bearing housing  36  and the orbiting scroll  54 . 
     The end plate  58  of the orbiting scroll  54  may include a first VVR port  74  and a second VVR port  76 . The first and second VVR ports  74 ,  76  may extend through the end plate  58  and are in selective fluid communication with the cavity  63  formed by the annular hub  62 . In some configurations, the end plate  58  may include a plurality of first VVR ports  74  and a plurality of second VVR ports  76 . The VVR valve assembly  22  may be disposed within the cavity  63  and may be mounted to the end plate  58 . As will be described in more detail below, the VVR valve assembly  22  is operable to selectively allow and restrict communication between the first and second VVR ports  74 ,  76  and the cavity  63 . The cavity  63  is in communication with the discharge chamber  24  via gaps between the hub  62  and the drive bearing  64 , between the drive bearing  64  and drive bushing  66 , and/or between the drive bushing  66  and the crank pin  52 . In some configurations, cavity  63  is in communication with the discharge chamber  24  via flow passages formed in any one or more of the hub  62 , drive bearing  64 , or drive bushing  66 , for example. Therefore, the VVR valve assembly  22  is operable to selectively allow and restrict communication between the first and second VVR ports  74 ,  76  and the discharge chamber  24 . 
     The non-orbiting scroll  56  may include an end plate  78  and a spiral wrap  80  projecting downwardly from the end plate  78 . The spiral wrap  80  may meshingly engage the spiral wrap  60  of the orbiting scroll  54 , thereby creating a series of moving fluid pockets therebetween. The fluid pockets defined by the spiral wraps  60 ,  80  may decrease in volume as they move from a radially outer position  82  ( FIG. 2 ) to a radially intermediate position  84  ( FIG. 2 ) to a radially inner position  86  ( FIG. 2 ) throughout a compression cycle of the compression mechanism  20 . The inlet fitting  34  is fluidly coupled with a suction inlet in the end plate  78  and provides suction-pressure working fluid to the fluid pockets at the radially outer positions  82 . The end plate  78  may include a discharge passage  88  in communication with one of the fluid pockets at the radially inner position  86  and allows compressed working fluid (at the high pressure) to flow into the discharge chamber  24 . The first and second VVR ports  74 ,  76  are disposed radially outward relative to the discharge passage  88  and communicate with respective fluid pockets in the radially intermediate positions  84 , as shown in  FIG. 2 . 
     As described above, the VVR valve assembly  22  may be disposed within the cavity  63  and may be mounted to the end plate  58  of the orbiting scroll  54 . The VVR valve assembly  22  may include a valve member  90  and a retainer (backer plate)  92 . The valve member  90  may be a thin and resiliently flexible elongated reed valve having a first end portion  94 , and a second end portion  96 , and a central portion  98  disposed between the first and second end portions  94 ,  96 . An aperture  100  extends through the central portion  98 . The retainer  92  may be a rigid elongated member having a first end portion  102 , a second end portion  104 , and a central portion  106  disposed between the first and second end portions  102 ,  104 . An aperture  108  extends through the central portion  106 . A fastener  110  (e.g., a bolt, rivet, etc.) may extend through the apertures  100 ,  108  of the valve member  90  and retainer  92  and may engage the end plate  58  of the orbiting scroll  54  to fixedly secure the retainer  92  and the central portion  98  of the valve member  90  to the end plate  58  (i.e., such that the valve member  90  is sandwiched between the retainer  92  and the end plate  58 ). One or more pins  112  ( FIG. 4 ) (or one or more additional fasteners) may also extend through corresponding apertures in the retainer  92  and valve member  90  and into corresponding apertures in the end plate  58  to rotationally fix the retainer  92  and valve member  90  relative to the end plate  58 . 
     The first and second end portions  102 ,  104  of the retainer may be tapered or angled to form gaps between distal ends of the first and second end portions  102 ,  104  and the end plate  58 . The gaps provide clearance to allow the first and second end portions  94 ,  96  of the valve member  90  to bend (relative to the central portion  98 ) away from the end plate  58 . 
     The VVR ports  74 ,  76  and the VVR valve assembly  22  are operable to prevent the compression mechanism  20  from over-compressing working fluid. Over-compression is a compressor operating condition where the internal compressor-pressure ratio of the compressor (i.e., a ratio of a pressure of a fluid pocket in the compression mechanism at a radially innermost position to a pressure of a fluid pocket in the compression mechanism at a radially outermost position) is higher than a pressure ratio of a climate-control system in which the compressor is installed (i.e., a ratio of a pressure at a high side of the climate-control system to a pressure of a low side of the climate-control system). In an over-compression condition, the compression mechanism is compressing fluid to a pressure higher than the pressure of fluid downstream of a discharge fitting of the compressor. Accordingly, in an over-compression condition, the compressor is performing unnecessary work, which reduces the efficiency of the compressor. The VVR valve assembly  22  of the present disclosure may reduce or prevent over-compression by selectively venting the fluid pockets at the radially intermediate positions  84  to the discharge chamber  24  (via the VVR ports  74 ,  76  and the cavity  63 ) when the pressure within such fluid pockets has exceeded (or sufficiently exceeded) the pressure in the discharge chamber  24 . 
     When fluid pressure within fluid pockets at the radially intermediate positions  84  are sufficiently higher (i.e., higher by a predetermined value determined based on the spring rate of the valve member  90 ) than the fluid pressure within the discharge chamber  24 , the fluid pressure within the fluid pockets at the radially intermediate positions  84  can bend the end portions  94 ,  96  of the valve member  90  away from the end plate  58  to an open position (shown in  FIG. 3 ) to open the VVR ports  74 ,  76  and allow communication between the VVR ports  74 ,  76  and the cavity  63 . That is, while the VVR ports  74 ,  76  are open (i.e., while the end portions  94 ,  96  are the open position), working fluid in the fluid pockets at the radially intermediate positions  84  can flow into the discharge chamber  24  (via the VVR ports  74 ,  76  and the cavity  63 ). When the fluid pressures within fluid pockets at the radially intermediate positions  84  are less than, equal to, or not sufficiently higher than the fluid pressure within the discharge chamber  24 , the end portions  94 ,  96  of the valve member  90  will return to a closed position (shown in  FIG. 2 ) (i.e., end portions  94 ,  96  return to their normal shapes) and seal against the end plate  58  to restrict or prevent communication between the cavity  63  and the VVR ports  74 ,  76 . 
     It will be appreciated that the end portions  94 ,  96  can move between the open and closed positions together or independently of each other based on the fluid pressures within the respective fluid pockets to which the respective VVR ports  74 ,  76  are exposed. In other words, one of the end portions  94 ,  96  could be in the open position while the other of the end portions  94 ,  96  could be in the closed position. 
     Referring now to  FIGS. 5-7 , another VVR valve assembly  122  and another orbiting scroll  154  are provided. The VVR valve assembly  122  and orbiting scroll  154  could be incorporated into the compressor  10  instead of the VVR valve assembly  22  and orbiting scroll  54 . The structure and function of VVR valve assembly  122  and orbiting scroll  154  can be similar or identical to that of the VVR valve assembly  22  and orbiting scroll  54  described above, apart from any exceptions described below. Therefore, some similar features and functions will not be described again in detail. 
     Like the orbiting scroll  54 , the orbiting scroll  154  may include an end plate  158  having a spiral wrap  160  extending therefrom. An annular hub  162  may project downwardly from the end plate  158  and may include a cavity  163  in which a drive bearing  164 , the drive bushing  66  (not shown in  FIGS. 5-7 ) and the crank pin  52  (not shown in  FIGS. 5-7 ) may be disposed. The cavity  163  is in communication with the discharge chamber  24  of the compressor  10 . The end plate  158  of the orbiting scroll  154  may include one or more first VVR ports  174  and one or more second VVR ports  176 . The first and second VVR ports  174 ,  176  may extend through the end plate  158  and are in selective fluid communication with the cavity  163  formed by the annular hub  162 . 
     The VVR valve assembly  122  may be disposed within the cavity  163  and may be mounted to the end plate  158  of the orbiting scroll  154 . The VVR valve assembly  122  may include a first valve member  190 , a second valve member  191 , a retainer  192 , a first spring  194 , and a second spring  196 . 
     The first and second valve members  190 ,  191  may be disc-shaped members and may include one or more flow passages (cutouts)  198  formed in their peripheries, as shown in  FIG. 7 . The first valve member  190  may be movably received within a first recess  200  formed in the end plate  158 . The first recess  200  may be generally aligned with and in communication with the first VVR port(s)  174 . The second valve member  191  may be movably received within a second recess  201  formed in the end plate  158 . The second recess  201  may be generally aligned with and in communication with the second VVR port(s)  176 . Valve seats  203 ,  205  are formed at the end of respective recesses  200 ,  201  and surround respective VVR ports  174 ,  176 . 
     The retainer  192  may be a rigid elongated member having a first end portion  202 , a second end portion  204 , and a central portion  206  disposed between the first and second end portions  202 ,  204 . One or more fasteners  209  (e.g., bolts, rivets, etc.) may extend through one or more apertures  208  in the central portion  206  and may engage the end plate  158  to fixedly secure the retainer  192  to the end plate  158 . The end portions  202 ,  204  of the retainer  192  may be angled relative to the central portion  206 . 
     First and second pins  210 ,  211  may extend from respective end portions  202 ,  204  and may extend into the respective recesses  200 ,  201  and partially through respective springs  194 ,  196 . The first spring  194  is disposed between and in contact with the first end portion  202  and the first valve member  190 . The second spring  196  is disposed between and in contact with the second end portion  204  and the second valve member  191 . 
     The valve members  190 ,  191  are movable within the recesses  200 ,  201  between an open position in which the valve members  190 ,  191  are spaced apart from the valve seats  203 ,  205  and closed positions in which the valve members  190 ,  191  are in contact with the valve seats  203 ,  205 . The first and second springs  194 ,  196  bias the first and second valve members  190 ,  191  toward the closed position. In the closed position, the valve members  190 ,  191  restrict or prevent fluid flow from the VVR ports  174 ,  176  to the cavity  163 . In the open position, the valve members  190 ,  191  allow working fluid to flow from the VVR ports  174 ,  176  into the recesses  200 ,  201 , through the flow passages  198  in the valve members  190 ,  191  and into the cavity  163  and into the discharge chamber  24 . 
     It will be appreciated that the valve members  190 ,  191  can move between the open and closed positions together or independently of each other based on the fluid pressures within the respective fluid pockets to which the respective VVR ports  174 ,  176  are exposed. In other words, as shown in  FIG. 5 , one of the valve members  190 ,  191  could be in the open position while the other of the valve members  190 ,  191  could be in the closed position. 
     Referring now to  FIGS. 8 and 9 , another VVR valve assembly  222  and another orbiting scroll  254  are provided. The VVR valve assembly  222  and orbiting scroll  254  could be incorporated into the compressor  10  instead of the VVR valve assembly  22  and orbiting scroll  54 . The structure and function of VVR valve assembly  222  and orbiting scroll  254  can be similar or identical to that of the VVR valve assembly  22  and orbiting scroll  54  described above, apart from any exceptions described below. Therefore, some similar features and functions will not be described again in detail. 
     Like the orbiting scroll  54 , the orbiting scroll  254  may include an end plate  258  having a spiral wrap  260  extending therefrom. An annular hub  262  may project downwardly from the end plate  258  and may include a cavity  263  in which a drive bearing  264 , the drive bushing  66  (not shown in  FIGS. 8 and 9 ) and the crank pin  52  (not shown in  FIGS. 8 and 9 ) may be disposed. Like the orbiting scroll  54 , the end plate  258  of the orbiting scroll  254  may include one or more first VVR ports  274  and one or more second VVR ports  276 . The VVR valve assembly  222  may operate in the same manner as the VVR valve assembly  22  to control fluid flow through VVR ports  274 ,  276 . 
     The hub  262  may be a two-piece hub including a first annular member  280  and a second annular member  282 . The first annular member  280  may be integrally formed with the end plate  258 . The second annular member  282  may be partially received within the first annular member  280  and may receive the drive bearing  264 . In some configurations, the second annular member  282  may include one or more flow passages  284  that extend through the second annular member  282 , as shown in  FIG. 8 . 
     Referring now to  FIGS. 10 and 11 , another VVR valve assembly  322  and another orbiting scroll  354  are provided. The VVR valve assembly  322  and orbiting scroll  354  could be incorporated into the compressor  10  instead of the VVR valve assembly  22  and orbiting scroll  54 . The structure and function of the orbiting scroll  354  can be similar or identical to that of the orbiting scroll  254  described above, apart from any exceptions described below. The structure and function of the VVR valve assembly  322  can be similar or identical to that of the VVR valve assembly  122  described above, apart from any exceptions described below. Therefore, some similar features and functions will not be described again in detail. 
     Like the orbiting scroll  254 , the orbiting scroll  354  may include an end plate  358  having a spiral wrap  360  extending therefrom. An annular hub  362  may project downwardly from the end plate  358  and may include a cavity  363  in which a drive bearing  364 , the drive bushing  66  (not shown in  FIGS. 10 and 11 ) and the crank pin  52  (not shown in  FIGS. 10 and 11 ) may be disposed. Like the orbiting scroll  254 , the end plate  358  of the orbiting scroll  354  may include one or more first VVR ports  374 , one or more second VVR ports  376 , a first recess  375 , and a second recess  377 . The first recess  375  may be in communication with and generally aligned with the first VVR port(s)  374 . The second recess  377  may be in communication with and generally aligned with the second VVR port(s)  376 . The VVR valve assembly  322  may operate in the same or similar manner as the VVR valve assembly  122  to control fluid flow through VVR ports  374 ,  376 . 
     The hub  362  may be a two-piece hub including a first annular member  380  and a second annular member  382 . The first annular member  380  may be integrally formed with the end plate  358 . The second annular member  382  may be partially received within the first annular member  380  and may receive the drive bearing  364 . In some configurations, the second annular member  382  may include one or more flow passages  384  that extend through the second annular member  382 , as shown in  FIG. 11 . In some configurations, an upper axial end of the second annular member  382  (i.e., the end adjacent the end plate  358 ) may include tabs  386  that extend radially inwardly therefrom, as shown in  FIG. 10 . 
     Like the VVR valve assembly  122 , the VVR valve assembly  322  may include first and second valve members  390 ,  391 , first and second springs  394 ,  396 , and first and second pins  310 ,  311 . The valve members  390 ,  391  may be similar or identical to the valve members  190 ,  191 . The tabs  386  of the second annular member  382  of the hub  362  may be fixed relative to the end plate  358  and may take the place of (and have the same or similar function as the retainer  192 ). The pins  310 ,  311  may be mounted to respective tabs  386 , may extend into respective recesses  375 ,  377 , may extend partially through respective springs  394 ,  396 , and may be in contact with respective valve members  390 ,  391 . Like the valve members  190 ,  191 , the valve members  390 ,  391  are movable within the recesses  375 ,  377  between open and closed positions to control fluid flow through the VVR ports  374 ,  376 . 
     Referring now to  FIGS. 12 and 13 , another VVR valve assembly  422  and another orbiting scroll  454  are provided. The VVR valve assembly  422  and orbiting scroll  454  could be incorporated into the compressor  10  instead of the VVR valve assembly  22  and orbiting scroll  54 . The structure and function of the orbiting scroll  454  can be similar or identical to that of the orbiting scroll  54  described above, apart from any exceptions described below. The structure and function of the VVR valve assembly  422  can be similar or identical to that of the VVR valve assembly  322  described above, apart from any exceptions described below. Therefore, some similar features and functions will not be described again in detail. 
     Like the orbiting scroll  54 , the orbiting scroll  454  may include an end plate  458  having a spiral wrap  460  extending therefrom. An annular hub  462  may project downwardly from the end plate  458  and may include a cavity  463  in which a drive bearing  464 , the drive bushing  66  (not shown in  FIGS. 12 and 13 ) and the crank pin  52  (not shown in  FIGS. 12 and 13 ) may be disposed. 
     The orbiting scroll  454  may include a first portion  455  and a second portion  456  attached to the first portion  455  by a plurality of fasteners  457 . The first portion  455  may include the spiral wrap  460  and a portion of the end plate  458  having a plurality of VVR ports  474  and a plurality of recesses  475 . Like recesses  200 ,  201 , the recesses  475  define valve seats. Each recess  475  is in communication with and generally aligned with a respective VVR port  474 . The second portion  456  may include another portion of the end plate  458  and the annular hub  462 . The portion of the end plate  458  defined by the second portion  456  may include a radially extending flow passage  476  in communication with the recesses  475  and one or more axially extending flow passages  477  in communication with the radially extending flow passage  476 . In the configuration shown  FIG. 12 , one of the axially extending flow passages  477  opens into the cavity  463  and the other axially extending flow passages  477  extending axially through the hub  462  and are disposed radially outward relative to the cavity  463 . The axially extending flow passages  477  are directly or indirectly in communication with the discharge chamber  24 . 
     The VVR valve assembly  422  may include a plurality of valve members  490  (which may be similar or identical to the valve members  190 ,  191 ), a plurality of springs  494  (which may be similar or identical to the springs  194 ,  196 ), and a plurality of pins  496  (which may be similar or identical to the pins  210 ,  211 ). The pins  496  are mounted to the second portion  456  of the orbiting scroll  454  and may extend partially into respective recesses  475 . The valve members  490  are movable within recesses  475  between open and closed positions to control fluid flow between the VVR ports  474  and the flow passages  476 ,  477  in the same or similar manner in which valve members  190 ,  191  control fluid flow between VVR ports  174 ,  176  and the cavity  163 . 
     Referring now to  FIGS. 14-16 , another VVR valve assembly  522  and another orbiting scroll  554  are provided. The VVR valve assembly  522  and orbiting scroll  554  could be incorporated into the compressor  10  instead of the VVR valve assembly  22  and orbiting scroll  54 . The structure and function of the orbiting scroll  554  can be similar or identical to that of the orbiting scroll  54  or  254  described above, apart from any exceptions described below. Therefore, some similar features and functions will not be described again in detail. 
     Like the orbiting scroll  254 , the orbiting scroll  554  may include an end plate  558  having a spiral wrap  560  extending therefrom. An annular hub  562  may project downwardly from the end plate  558  and may include a cavity  563  in which a drive bearing  564 , the drive bushing  66  (not shown in  FIGS. 14-16 ) and the crank pin  52  (not shown in  FIGS. 14-16 ) may be disposed. Like the orbiting scroll  254 , the end plate  558  of the orbiting scroll  554  may include one or more first VVR ports  574 , and one or more second VVR ports  576 . Each of the first and second VVR ports  574 ,  576  may include an axially extending portion  577  and a radially extending portion  579  that extends radially inward from the axially extending portion  577  to the cavity  563 . The VVR valve assembly  522  controls fluid flow through VVR ports  574 ,  576 . 
     The hub  562  may be a two-piece hub including a first annular member  580  and a second annular member  582 . The first annular member  580  may be integrally formed with the end plate  558 . A portion of the axially extending portions  577  of the VVR ports  574 ,  576  may extend through the first annular member  580 , and the radially extending portions  579  of the VVR ports  574 ,  576  extend through a portion of the first annular member  580 . The second annular member  582  may be partially received within the first annular member  580  and may receive the drive bearing  564 . The second annular member  582  may include one or more flow passages  584  that extend through the second annular member  582 , as shown in  FIG. 14 . As shown in  FIG. 16 , a contoured recess  586  is formed in an outer diametrical surface  587  of the second annular member  582 . The recess  586  is open to the flow passages  584 . The recess  586  partially encircles the drive bearing  564  (i.e., the recess  586  extends partially around the circumference of the crank pin  52 ). 
     The VVR valve assembly  522  may include a valve member  590  that is received within the recess  586  of the second annular member  582 . The valve member  590  may be a generally C-shaped, thin and resiliently flexible reed valve having a first end portion  592 , and a second end portion  594 , and a central portion  596  disposed between the first and second end portions  592 ,  594 . The contoured recess  586  of the second annular member  582  may be shaped to fixedly receive the central portion  596  and movably receive the first and second end portions  592 ,  594  such that the first and second end portions  592 ,  594  are able to flex between outward and inward between closed positions (in which the end portions  592 ,  594  are in contact with an inner diametrical surface  598  of the first annular member  580 ) and open positions (in which the end portions  592 ,  594  are spaced apart from the inner diametrical surface  598  of the first annular member  580 ). 
     In  FIGS. 14 and 15 , the first end portion  592  is shown in the open position in which the first end portion  592  has moved (e.g., flexed) inward away from the inner diametrical surface  598  to allow communication between the first VVR port  574  and one of the flow passages  584  (the flow passages  584  are in communication with the cavity  563  and the discharge chamber  24 ). In  FIGS. 14 and 15 , the second end portion  594  is shown in the closed position in which the second end portion  594  has moved (e.g., unflexed) outward into contact with the inner diametrical surface  598  to close off the second VVR port  576  to restrict or prevent communication between the second VVR port  576  and the flow passages  584  (thus restricting or preventing communication between the second VVR port  576  and the discharge chamber  24 ). It will be appreciated that the end portions  592 ,  594  of the valve member  590  can move between the open and closed positions together or independently of each other based on the fluid pressures within the respective fluid pockets to which the respective VVR ports  574 ,  576  are exposed. 
     Referring now to  FIG. 17 , another compressor  610  is provided. The structure and function of the compressor  610  may be similar or identical to that of the compressor  10  described above, apart from differences noted below and/or shown in the figures. Therefore, similar features will not be described again in detail. 
     Like the compressor  10 , the compressor  610  may be a high-side scroll compressor including a hermetic shell assembly  612 , a first and second bearing assemblies  614 ,  616 , a motor assembly  618 , a compression mechanism  620 , and a variable-volume-ratio (VVR) valve assembly  622 . The first bearing assembly  614  may be generally similar to the first bearing assembly  14  (i.e., the first bearing assembly  614  is fixed to the shell assembly  612 , rotationally supports a driveshaft  648 , and axially supports an orbiting scroll  654 ). 
     The driveshaft  648  may include an end portion (e.g., a collar portion)  649  having an eccentric recess  650  that receives a drive bearing  664  and a hub  662  of the orbiting scroll  654 . The end portion  649  may include a flow passage  652  that provides communication between a discharge chamber  624  of the compressor  610  and a cavity  663  in the hub  662  (i.e., to provide communication between VVR ports  674 ,  676  and the discharge chamber  624 ). 
     The VVR valve assembly  622  can be similar or identical to any of the VVR valve assemblies  22 ,  122 ,  322 ,  422 ,  522  described above. The orbiting scroll  654  can be similar to any of the orbiting scrolls  54 ,  154 ,  254 ,  354 ,  454 ,  554  described above. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.