Patent Publication Number: US-7717687-B2

Title: Scroll compressor with compliant retainer

Description:
FIELD 
   The present disclosure relates to scroll compressors, and more specifically to scroll retaining devices. 
   BACKGROUND 
   The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
   Typically, scroll compressors may include orbiting and non-orbiting scrolls. The non-orbiting scroll may be coupled to a fixed structure of the compressor, such as a main bearing housing. This attachment may be achieved in a variety ways, such as through the use of threaded fasteners. The use of fasteners, however, complicates assembly and promotes the transmission of vibrations from the non-orbiting scroll to the main bearing housing during compressor operation. 
   SUMMARY 
   According to the present disclosure, a scroll compressor may include a shell, a housing, a compression mechanism, an Oldham coupling, and a retaining member. The housing may be supported within the shell and may include a support structure therein. The compression mechanism may be supported within the housing and may include first and second scroll members meshingly engaged with one another. The Oldham coupling may be engaged with the first and second scroll members and may prevent relative rotation therebetween. The retaining member may include a radially compliant geometry disposed between the support structure and an outer surface of the first scroll member. 
   In an alternate arrangement, a scroll compressor may include a shell, a housing, a compression mechanism, and a retaining member. The housing may be supported within the shell and may include a support member therein. The compression mechanism may include first and second scroll members meshingly engaged with one another and supported within the housing. The retaining member may include a ring-like body with an inner surface disposed around an outer surface of the compression mechanism and an outer surface engaged with the support structure. The retaining member may provide a predetermined axial displacement limit for the first scroll member relative to the second scroll member. 
   Alternatively, a scroll compressor may include a shell, a bearing housing, first and second scroll members, and a ring member. The bearing housing may be supported within the shell and may include at least three axially extending arms. The first scroll member may be supported on the bearing housing and may include a circumferential outer surface. The second scroll member may be supported on the bearing housing and may be meshingly engaged with the first scroll member. The second scroll member may be disposed between the first scroll member and the bearing housing. The ring member may include an open center portion surrounding the circumferential outer surface of the first scroll member. A portion of the ring member may be disposed between the arms of the bearing housing and the circumferential outer surface of the first scroll member. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples 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 illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       FIG. 1  is a section view of a compressor according to the present disclosure; 
       FIG. 2  is a perspective view of the compression mechanism shown in  FIG. 1  having a first retaining assembly; 
       FIG. 3  is a perspective exploded view of the compression mechanism and retaining assembly of  FIG. 2 ; 
       FIG. 4  is a perspective view of a portion of the retaining assembly shown in  FIG. 2 ; 
       FIG. 5  is a perspective view of a compression mechanism having a second retaining assembly; 
       FIG. 6  is a perspective exploded view of the compression mechanism and retaining assembly of  FIG. 5 ; 
       FIG. 7  is a perspective view of a compression mechanism having a third retaining assembly; 
       FIG. 8  is a perspective exploded view of the compression mechanism and retaining assembly of  FIG. 7 ; and 
       FIG. 9  is a perspective view of a portion of a fourth retaining assembly. 
   

   DETAILED DESCRIPTION 
   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. 
   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 . 
   With reference to  FIG. 1 , compressor  10  may include a cylindrical hermetic shell  12 , a compression mechanism  14 , a main bearing housing  16 , a motor assembly  18 , a refrigerant discharge fitting  20 , and a suction gas inlet fitting  22 . Hermetic shell  12  may house compression mechanism  14 , main bearing housing  16 , and motor assembly  18 . Shell  12  may include an end cap  24  at the upper end thereof, a transversely extending partition  26 , and a base  28  at a lower end thereof. End cap  24  and transversely extending partition  26  may generally define a discharge muffler  30 . Refrigerant discharge fitting  20  may be attached to shell  12  at opening  32  in end cap  24 . Suction gas inlet fitting  22  may be attached to shell  12  at opening  34 . Compression mechanism  14  may be driven by motor assembly  18  and supported by main bearing housing  16 . Main bearing housing  16  may be affixed to shell  12  at a plurality of points in any desirable manner, such as staking. 
   Motor assembly  18  may generally include a motor stator  36 , a rotor  38 , and a drive shaft  40 . Motor stator  36  may be press fit into shell  12 . Drive shaft  40  may be rotatably driven by rotor  38 . Windings  42  may pass through stator  36 . Rotor  38  may be press fit on drive shaft  40 . A motor protector  44  may be provided in close proximity to windings  42  so that motor protector  44  will de-energize motor assembly  18  if windings  42  exceed their normal temperature range. 
   Drive shaft  40  may include an eccentric crank pin  46  having a flat  48  thereon and one or more counter-weights  50 ,  52 . Drive shaft  40  may include a first journal portion  54  rotatably journaled in a first bearing  56  in main bearing housing  16  and a second journal portion  58  rotatably journaled in a second bearing  60  in lower bearing housing  62 . Drive shaft  40  may include an oil-pumping concentric bore  64  at a lower end. Concentric bore  64  may communicate with a radially outwardly inclined and relatively smaller diameter bore  66  extending to the upper end of drive shaft  40 . The lower interior portion of shell  12  may be filled with lubricating oil. Concentric bore  64  may provide pump action in conjunction with bore  66  to distribute lubricating fluid to various portions of compressor  10 . 
   Compression mechanism  14  may generally include an orbiting scroll  68  and a non-orbiting scroll  70 . Orbiting scroll  68  may include an end plate  72  having a spiral vane or wrap  74  on the upper surface thereof and an annular flat thrust surface  76  on the lower surface. Thrust surface  76  may interface with an annular flat thrust bearing surface  78  on an upper surface of main bearing housing  16 . A cylindrical hub  80  may project downwardly from thrust surface  76  and may include a journal bearing  81  having a drive bushing  82  rotatively disposed therein. Drive bushing  82  may include an inner bore in which crank pin  46  is drivingly disposed. Crank pin flat  48  may drivingly engage a flat surface in a portion of the inner bore of drive bushing  82  to provide a radially compliant driving arrangement. 
   Non-orbiting scroll  70  may include an end plate  84  having a spiral wrap  86  on a lower surface thereof. Spiral wrap  86  may form a meshing engagement with wrap  74  of orbiting scroll  68 , thereby creating an inlet pocket  88 , intermediate pockets  90 ,  92 ,  94 ,  96 , and an outlet pocket  98 . Non-orbiting scroll  70  may have a centrally disposed discharge passageway  100  in communication with outlet pocket  98  and upwardly open recess  102  which may be in fluid communication with discharge muffler  30  via an opening  104  in partition  26 . 
   Non-orbiting scroll  70  may include an annular recess  106  in the upper surface thereof having parallel coaxial side walls in which an annular floating seal  108  is sealingly disposed for relative axial movement. The bottom of recess  106  may be isolated from the presence of gas under suction and discharge pressure by floating seal  108  so that it can be placed in fluid communication with a source of intermediate fluid pressure by means of a passageway (not shown). The passageway may extend into an intermediate pocket  90 ,  92 ,  94 ,  96 . Non-orbiting scroll  70  may therefore be axially biased against orbiting scroll  68  by the forces created by discharge pressure acting on the central portion of non-orbiting scroll  70  and those created by intermediate fluid pressure acting on the bottom of recess  106 . Retaining member  110  may secure non-orbiting scroll  70  to main bearing housing  16  for limited axial movement therebetween, as discussed below. Relative rotation of orbiting and non-orbiting scrolls  68 ,  70  may be prevented by an Oldham coupling  112 , as discussed below. 
   With reference to  FIGS. 2 and 3 , main bearing housing  16  may include a radially extending body portion  114  having three arms  116 ,  118 ,  120  extending axially upwardly therefrom. More specifically, arms  116 ,  118 ,  120  may extend axially upwardly to a location at least at a midpoint of one of wraps  74 ,  86 . Each of arms  116 ,  118 ,  120  may be generally similar to one another. Therefore, arm  116  will be discussed with the understanding that the description applies equally to arms  118 ,  120 . Arm  116  may include first and second portions  122 ,  124  having first and second inner diameters. First portion  122  may be disposed between second portion  124  and body portion  114 . First portion  122  may have an inner diameter that is greater than the inner diameter of second portion  124 , forming a step  126  therebetween. A lip  128  may be located at an axially outer end of arm  116  and may have an inner diameter that is less than the inner diameter of second portion  124 . 
   Oldham coupling  112  may be a two-up stacked Oldham including a ring  129  and first and second keys  130 ,  132 . Keys  130 ,  132  may each include first portions  134 ,  136  and second portions  138 ,  140 . Oldham coupling  112  may be disposed on and abut body portion  114 . The outer diameter of ring  129  may be generally similar to the inner diameter of first portion  122 , locating Oldham coupling  112  within arms  116 ,  118 ,  120 . Orbiting scroll  68  may abut thrust surface  76  and may be disposed adjacent Oldham coupling  112 . Orbiting scroll  68  may include flanges  142 ,  144  having slots  146 ,  148  slidably engaged with first portions  134 ,  136  of keys  130 ,  132 . Non-orbiting scroll  70  may be meshingly engaged with orbiting scroll  68  and may include flanges (only one of which is shown)  150  having slots  152  slidably engaged with second portions  138 ,  140  of keys  130 ,  132 . Retaining member  110  may be disposed around an outer surface  155  of non-orbiting scroll  70  and may secure orbiting scroll  68 , non-orbiting scroll  70 , and Oldham coupling  112  to main bearing housing  16 . 
   More specifically, retaining member  110  may secure orbiting scroll  68 , non-orbiting scroll  70 , and Oldham coupling  112  to main bearing housing  16  without the use of any fasteners. Retaining member  110  may include a generally circular body having an upwardly extending U-shaped cross-section having upwardly extending inner and outer legs  111 ,  113  and a transversely extending base  115 . Retaining member  110  may have a series of radially outwardly extending flanged portions  154 ,  156 ,  158  at an upper end thereof, forming a series of recesses  160 ,  162 ,  164  therebetween. Recesses  160 ,  162 ,  164  may generally correspond to arms  116 ,  118 ,  120 . Retaining member  110  may be retained within second portion  124  of arms  116 ,  118 ,  120 . 
   The outer diameter of retaining member  110  may be less than the inner diameter of arm second portion  124  and greater than the inner diameter of arm first portion  122  and lip  128 , axially securing retaining member  110 , and therefore orbiting scroll  68 , non-orbiting scroll  70 , and Oldham coupling  112 , to main bearing housing  16 . More specifically, retaining member  110  may be captured between step  126  and lip  128 . Alternatively, retaining member  110  may be captured between step  126  and partition  26 . A clearance may be provided for axial displacement of non-orbiting scroll  70  relative to main bearing housing  16 . The clearance may be located between an upper surface of flange  150  of non-orbiting scroll  70  and a lower surface of base  115  of retaining member  110 . Alternatively, the distance between step  126  and lip  128  may be greater than the height of retaining member  110 . The outer diameter of retaining member  110  may be less than the inner diameter of arm second portion  124 , providing for axial displacement of retaining member  110  between step  126  and lip  128 . 
   Flanged portions  154 ,  156 ,  158  may have an outer diameter greater than the inner diameter of arm second portion  124 , rotationally securing retaining member  110  to main bearing housing  16 . The lower surface of base  115  of retaining member  110  may further include protrusions  166 ,  168  (shown in  FIG. 4 ) extending therefrom and into slots  152  in non-orbiting scroll  70 , rotationally securing non-orbiting scroll  70  to retaining member  110 , and therefore main bearing housing  16 . The U-shaped cross-section of retaining member  110  may provide for collection of returning oil. Apertures  170  may be located through base  115  and protrusions  166 ,  168  of retaining member  110  (shown in  FIG. 4 ) to allow oil to lubricate keys  130 ,  132  of Oldham coupling  112 . 
   The U-shaped retaining member  110  may be formed from a stamping. The U-shaped construction may generally allow for deflection of retaining member  110  during insertion into main bearing housing  16 . More specifically, outer leg  113  may deflect during insertion without distorting the roundness of the inner diameter of inner leg  111 . While retaining member  110  is shown secured to main bearing housing  16  through a snap-fit arrangement, it is understood that an interference fit engagement could be used as well, providing a predetermined axial clearance between non-orbiting scroll  70  and retaining member  110  for axial displacement of non-orbiting scroll  70  relative to retaining member  110  and main bearing housing  16  during compressor operation. When an interference fit engagement is used to couple retaining member  110  to main bearing housing  16 , retaining member  110  may have an uninstalled outer diameter that is greater than the inner diameter of arm second portion  124 . In either securing method, there is a mechanical engagement between retaining member  110  and main bearing housing  16 , eliminating the need for a fastener. Retaining member  110  may also provide for alignment of non-orbiting scroll  70 . 
   More specifically, the inner diameter of retaining member  110  may serve as a guide cylinder for outer surface  155  of non-orbiting scroll  70 . The U-shaped cross-section may absorb and dampen the forces applied by compression mechanism  14  to main bearing housing  16 , and therefore shell  12 , as a result of the elastic properties of retaining member  110 . 
   During assembly, Oldham coupling  112 , orbiting scroll  68 , and non-orbiting scroll  70  may be placed in main bearing housing  16  as described above. Retaining member  110  may then be snap-fit or interference fit to second portion  124  of arms  116 ,  118 ,  120  of main bearing housing  16 , axially retaining Oldham coupling  112 , orbiting scroll  68 , and non-orbiting scroll  70  between body portion  114  of main bearing housing  16  and retaining member  110 . More specifically, recesses  160 ,  162 ,  164  may be aligned with arms  116 ,  118 ,  120  before fitting retaining member  110  within arms  116 ,  118 ,  120 . Oldham coupling  112 , orbiting scroll  68 , and non-orbiting scroll  70  may be radially retained within arms  116 ,  118 ,  120  of main bearing housing  16 . 
   An alternate main bearing housing  216 , Oldham coupling  312 , orbiting scroll  268 , non-orbiting scroll  270 , and retaining member  310  are shown in  FIGS. 5 and 6  and may be generally similar to those shown in  FIGS. 3 and 4 . Main bearing housing  216  may include a radially extending body portion  314  having three arms  316 ,  318 ,  320  extending axially upwardly therefrom. More specifically, arms  316 ,  318 ,  320  may extend axially upwardly to a location at least at a midpoint of one of the wraps of orbiting and non-orbiting scrolls  268 ,  270 . Each of arms  316 ,  318 ,  320  may be generally similar to one another. Therefore, arm  316  will be discussed with the understanding that the description applies equally to arms  318 ,  320 . Arm  316  may include first and second portions  322 ,  324  having first and second inner diameters. First portion  322  may be disposed between second portion  324  and body portion  314 . First portion  322  may have an inner diameter that is greater than the inner diameter of second portion  324 , forming a step  326  therebetween. 
   Oldham coupling  312  may include a ring  329  and first and second keys  330 ,  332 . Keys  330 ,  332  may each include first portions  334 ,  336  and second portions  338 ,  340 . Oldham coupling  312  may be disposed on and abut body portion  314 . The outer diameter of ring  329  may be generally similar to the inner diameter of first portion  322 , locating Oldham coupling  312  within arms  316 ,  318 ,  320 . Orbiting scroll  268  may abut thrust surface  278  and may be disposed adjacent Oldham coupling  312 . Orbiting scroll  268  may include flanges  342 ,  344  having slots  346 ,  348  slidably engaged with first portions  334 ,  336  of keys  330 ,  332 . Non-orbiting scroll  270  may be meshingly engaged with orbiting scroll  268  and may include flanges (only one of which is shown)  350  having slots  352  slidably engaged with second portions  338 ,  340  of keys  330 ,  332 . Ends of flanges  350  on opposite sides of slots  352  may include upwardly extending protrusions  353 . Retaining member  310  may be disposed around an outer surface  355  of non-orbiting scroll  270  and may secure orbiting scroll  268 , non-orbiting scroll  270 , and Oldham coupling  312  to main bearing housing  216 . 
   More specifically, retaining member  310  may secure orbiting scroll  268 , non-orbiting scroll  270 , and Oldham coupling  312  to main bearing housing  216  without the use of any fasteners. Retaining member  310  may include a generally circular body having inner and outer diameter portions  311 ,  313 . Three recessed portions  360 ,  362 ,  364  may be located in outer diameter portion  313  and may generally correspond to arms  316 ,  318 ,  320  of main bearing housing  216 . Arcuate apertures  366 ,  368 ,  370  may extend axially through upper and lower surfaces of retaining member  310 . Apertures  366 ,  368 ,  370  may be located between inner and outer diameter portions  311 ,  313  at recessed portions  360 ,  362 ,  364 . First, second, and third portions  354 ,  356 ,  358  of retaining member  310  may be disposed between recessed portions  360 ,  362 ,  364  and may extend radially outwardly relative thereto. An additional recessed portion  372  may be located in third portion  358  and may have an arm  374  extending radially outwardly therefrom and located between protrusions  353  in non-orbiting scroll  270 . Locating arm  374  between protrusions  353  may prevent rotation of non-orbiting scroll  270  relative to retaining member  310 . 
   Recessed portions  360 ,  362 ,  364  may have an uninstalled outer diameter that is greater than the inner diameter of arm second portion  324 . When installed, recessed portions  360 ,  362 ,  364  may abut the radially inner surface of arm second portion  324  and may be deformed to have an outer diameter generally similar to arm second portion  324  creating an interference fit therebetween, axially fixing retaining member  310  to main bearing housing  216  without the use of any fasteners. First, second, and third portions  354 ,  356 ,  358  of retaining member  310  may have an outer diameter greater than the outer diameter of recessed portions  360 ,  362 ,  364  both before and after installation into main bearing housing  216 . As such, first, second, and third portions  354 ,  356 ,  358  have an outer diameter greater than the inner diameter of arm second portion  324 , preventing rotation of retaining member  310  relative to main bearing housing  216 . 
   A clearance may be provided for axial displacement of non-orbiting scroll  270  relative to main bearing housing  216 . The clearance may be located between an upper surface of flange  350  of non-orbiting scroll  270  and a lower surface of retaining member  310 . The engagement between arm  374  of retaining member  310  and protrusions  353  of non-orbiting scroll  270  may prevent relative rotation between non-orbiting scroll  270  and main bearing housing  216 . 
   Apertures  366 ,  368 ,  370  may generally allow for deflection of retaining member  310  during insertion into main bearing housing  216 . More specifically, outer diameter portion  313  may deflect at recessed portions  360 ,  362 ,  364  during insertion without distorting the roundness of inner diameter portion  311 . As indicated above, there is a mechanical engagement between retaining member  310  and main bearing housing  216 , eliminating the need for a fastener. Retaining member  310  may also provide for alignment of non-orbiting scroll  270 . 
   More specifically, the inner diameter of retaining member  310  may serve as a guide cylinder for outer surface  355  of non-orbiting scroll  270 . Apertures  366 ,  368 ,  370  may provide compliance in retaining member  310  at recessed portions  360 ,  362 ,  364 , which may therefore absorb and dampen the forces applied by compression mechanism  214  to main bearing housing  216 . 
   During assembly, Oldham coupling  312 , orbiting scroll  268 , and non-orbiting scroll  270  may be placed in main bearing housing  216  as described above. Retaining member  310  may then be press fit (or interference fit) onto second portion  324  of arms  316 ,  318 ,  320  of main bearing housing  216 , axially retaining Oldham coupling  312 , orbiting scroll  268 , and non-orbiting scroll  270  between body portion  314  of main bearing housing  216  and retaining member  310 . More specifically, recessed portions  360 ,  362 ,  364  may be aligned with arms  316 ,  318 ,  320  before fitting retaining member  310  within arms  316 ,  318 ,  320 . Oldham coupling  312 , orbiting scroll  268 , and non-orbiting scroll  270  may be radially retained within arms  316 ,  318 ,  320  of main bearing housing  216 . 
   An alternate main bearing housing  416 , Oldham coupling  512 , orbiting scroll  468 , non-orbiting scroll  470 , and retaining member  510  are shown in  FIGS. 7 and 8  and may be generally similar to those shown in  FIGS. 5 and 6 . However, Oldham coupling  512  is shown as a conventional four-up Oldham and main bearing housing  416  is shown having four arms  516 ,  518 ,  520 ,  521 . Therefore, for simplicity, main bearing housing  416 , Oldham coupling  512 , orbiting scroll  468 , non-orbiting scroll  470 , and retaining member  510  will not be described in detail with the understanding that the majority of the description regarding  FIGS. 5 and 6  applies equally to  FIGS. 7 and 8 . 
   An alternate retaining member  610  is shown in  FIG. 9 . Retaining member  610  may be used in any of the arrangements shown and may be generally similar to retaining member  110 , but oriented in the opposite direction. Retaining member  610  may include a generally circular body having a downwardly extending U-shaped cross-section having downwardly extending inner and outer legs  611 ,  613  and a transversely extending base  615 . Legs  611 ,  613  may allow for deflection for both installation and dampening as discussed above regarding retaining member  110 .