Abstract:
A scroll compressor includes a non-orbiting scroll having a plurality of radially extending ribs on its rear face. The non-orbiting scroll preferably provides a separating function separating the interior of the sealed housing of the compressor into the discharge and suction pressure chambers. The ribs extend from a central portion of the base of the non-orbiting scroll to its outer peripheral surface. A circumferentially extending rib also connects the plural radially extending ribs.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to a scroll compressor having a non-orbiting scroll with load bearing ribs.  
           [0002]    Modem refrigerant compressors are often mounted within a sealed container. In these compressors, the pump unit for compressing the refrigerant is positioned at one end, and a motor for driving the pump unit is positioned at another end. Often the suction pressure refrigerant is allowed to circulate over the motor, cooling the motor. In such compressors, it becomes necessary to separate a suction pressure chamber from a discharge pressure chamber.  
           [0003]    One popular type of modem compressor is a scroll compressor. A scroll compressor includes a pair of scroll members each having a base and a generally spiral wrap extending from the base. The wraps of the two scroll members interfit to define compression chambers. One of the scroll members is driven to orbit relative to the other, and during this orbital movement, the compression chambers decrease in volume.  
           [0004]    In traditional scroll compressors, the non-orbiting scroll does not seal against the compressor housing. Instead, a separate separator plate is positioned typically outwardly of the base of the non-orbiting scroll to separate the housing into the suction and discharge pressure chambers. Most typically, a discharge pressure chamber is formed above the separator plate, and the area below the separator plate is at suction pressure.  
           [0005]    More recently, it has been proposed to incorporate the separator function into the base of the non-orbiting scroll. In such compressors, the base of the non-orbiting scroll is sealed to the housing. Thus, there is the discharge pressure chamber on one side of the base of the non-orbiting scroll and the suction pressure chamber on the other.  
           [0006]    In such compressors, compressed refrigerant often reaches relatively high pressures. With the above discussed recent scroll compressor improvements, this high pressure may cause the scroll base to deform toward the suction side of the compressor. This deformation is undesirable.  
           [0007]    One proposed design employs ribs extending radially from the center of scroll base across a limited portion of the base. This design may not offer sufficient support to the base. Moreover, the design only offers support along a radial path from the base&#39;s center.  
           [0008]    A need therefore exists for a scroll base having greater support against deflection and deformation.  
         SUMMARY OF THE INVENTION  
         [0009]    In a disclosed embodiment of this invention, a scroll compressor has an orbiting scroll member and a non-orbiting scroll member. The non-orbiting scroll is utilized to separate a housing containing both scroll members into suction and discharge pressure chambers. Preferably, the non-orbiting scroll has an outer peripheral surface sealed to a inner peripheral surface of the housing defining the suction and discharge pressure chambers. Other ways of sealing the non-orbiting scroll to the housing may be used. To limit deflection of the non-orbiting scroll, ribs are formed on the outer face of the base of the scroll member. The ribs preferably offer support along a radial and non-radial path from the center and may extend across the entire scroll member.  
           [0010]    The ribs preferably extend from a center portion of the non-orbiting scroll member to the periphery of the member. The extension of ribs to the periphery permits the distribution of load caused by the pressure differential between the discharge pressure chamber and the suction pressure chamber across the entire member. In addition, a rib is preferably formed along the periphery to provide further support. This peripheral rib intersects the ribs extending from the center portion. The radially extending ribs meet in the center portion and connect to a boss of the non-orbiting scroll member. The non-orbiting scroll member typically has a circular outer peripheral shape.  
           [0011]    The ribs preferably form a radial design extending from the center portion of the base. In addition, the invention envisions the use of ribs so as to distribute loads not only radially but in a non-radial fashion across the non-orbiting scroll member. Alternate rib embodiments crisscross and intersect each other to distribute load across other portions of the non-orbiting scroll member. Some rib embodiments intersect at perpendicular angles.  
           [0012]    The present invention accordingly permits the non-orbiting member to be supported by ribbing and avoid deflections and deformities caused by their absence, thereby providing greater support to the non-orbiting member. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:  
         [0014]    [0014]FIG. 1A illustrates a cross sectional view of the invention, including a scroll member with ribs.  
         [0015]    [0015]FIG. 1B shows a prior art scroll member.  
         [0016]    [0016]FIG. 2 illustrates the FIG. 1A non-orbiting scroll member.  
         [0017]    [0017]FIG. 3 illustrates another embodiment non-orbiting scroll member  
         [0018]    [0018]FIG. 4 shows another non-orbiting scroll member with radial ribs.  
         [0019]    [0019]FIG. 5 illustrates another non-orbiting scroll member with non-radial and radial ribs.  
         [0020]    [0020]FIG. 6 illustrates a non-orbiting scroll member with ribs, a waffle pattern rib design. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    A scroll compressor  20  is illustrated in FIG. 1A. As known, scroll compressor  20  incorporates an orbiting scroll  22  and a non-orbiting scroll  24 . A center shell  26  is secured to an upper shell  28 . A discharge pressure chamber  32  is defined within upper shell  28 , discharging refrigerant through tube  30 . Non-orbiting scroll  24  has abase  100  and a spiral wrap  102  extending from the base. The orbiting scroll  22  similarly has a base  104  and a spiral wrap  106 . Compression chambers  108  are defined between the two wraps.  
         [0022]    In the non-orbiting scroll  24 , the base is sealed to periphery  35  of the upper shell  28 . The base itself can form a seal, or a separate seal element can be used. A shaft  36  is driven by motor  137  to drive the orbiting scroll  22 . A suction tube  38  extends through the center shell  26  to supply refrigerant to chamber  40 . As can be seen, suction tube  38  is positioned on a side of orbiting scroll  22  remote from non-orbiting scroll  24 . The sealing joint between the base of non-orbiting scroll  24  and the upper shell  28  divides the interior of the housing into the discharge pressure chamber  32  and the suction pressure chamber  40 .  
         [0023]    Boss  42  on base receives a check valve assembly  44 , shown schematically. Refrigerant is compressed between the orbiting and non-orbiting scrolls  22  and  24  and passes through check valve  44  into chamber  32 . Refrigerant in discharge pressure chamber  32  is at high pressure while suction pressure chamber  40  is at low pressure. The difference in pressure may cause non-orbiting scroll to deflect or deform toward suction pressure chamber  40 . High temperature of the non-orbiting scroll may also cause deformation.  
         [0024]    [0024]FIG. 1B illustrates a prior art design. Shown is non-orbiting scroll member  10  with ribs  12  extending from center  14  along a radial direction. As shown in this figure, ribs  12  extend only across a limited portion of non-orbiting scroll member  10 . Thus, scroll member  10  is supported only across this portion along a radial path from center  14 .  
         [0025]    To increase support, the inventive non-orbiting scroll member  24  is reinforced by several ribs  50 , extending from boss  42  to about periphery  37 . Periphery  37  meets wall  33  of upper shell  28  as shown. In this way, ribs  50  provide support against deflection from boss  42  to periphery  37  across the great majority of member  24 . Each rib  50  has first portion  52  extending above land  62  of base  100  and second portion  54  extending above land  64  of base  100 , reinforcing both areas to prevent deflection of base  100 . As shown, land  64  is elevated relative to land  62  essentially by a circumferentially extending portion, or rib  180 .  
         [0026]    [0026]FIG. 2 illustrates the non-orbiting scroll employing the inventive features of this invention. Boss  42  is located in a center portion of non-orbiting scroll  24 . Boss  42  has passage  74  to permit the communication of refrigerant between the compression chamber and the discharge pressure chamber. Non-orbiting scroll  24  comprises base  100 , which itself comprises land  62 , land  64  and central portion  82 . Land  62  encircles land  64 , which encircles boss  42 . Moreover, as shown in this figure, land  64  is elevated above land  62  and shares circumferential rib  180 , which provides the elevated position of land  64  with respect to land  62 . Boss  42  may be elevated above both land  62  and land  64 . Supporting base  100  further are radial ribs  50 , which may extend from center point  88  to about periphery  37 . Periphery  37  is positioned inwardly of outer periphery  94 . Periphery  37  is elevated above outer periphery  94  to form a circumferential lip  34  which may abut upper shell  28  as shown in FIG. 1.  
         [0027]    [0027]FIG. 3 illustrates another non-orbiting scroll  110  having base  112 , boss  114  and ribs  116  radiating from boss  114 . This particular design also employs rib  118  extending circumferentially around periphery  120  of base  112 . Rib  118  may provide additional support to base  112  and intersect radial ribs  116 . Moreover, rib  118  may form part of the sealing surface for an upper shell of a sealed housing.  
         [0028]    [0028]FIGS. 4, 5 and  6  illustrate other rib patterns. FIG. 4 shows non-orbiting scroll  126  with base  130  and boss  134 . Base  130  is reinforced by ribs, such as rib  138 , extending radially from boss  134  to inner periphery  142 . Inner periphery  142  is within outer periphery  144 .  
         [0029]    In addition, base  130  may be reinforced by non-radial ribs such as rib  156 , which extends along a path that does cross center  150 . Rib  156  may extend transversely from rib  138 , a radial rib. Rib  158  is also provided, extending circumferentially about inner periphery  142  and may intersect rib  138  and rib  156 . In this way, the invention provides support radially and non-radially across base  130 , distributing load over, through and around center  150 .  
         [0030]    [0030]FIG. 5 illustrates another non-orbiting scroll  159  having center point  160  and ribs  162  and  163  radiating from center point  160 . Here, rib  164  is formed that is transverse to ribs  162  and  163  and does not pass through center point  160 .  
         [0031]    [0031]FIG. 6 illustrates a waffle pattern design, highlighting again the non-radial rib feature of the invention. Rib  176  extends across base  174  of non-orbiting scroll  178  along a path that does not extend through center  170 . Another non-radial rib  173  may intersect rib  176  perpendicularly at point A. One of ordinary skill in the art can envision other ways to employ both radial and non-radial ribs to support a non-orbiting scroll to avoid deformation and its deflection.  
         [0032]    The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.