Abstract:
A scroll compressor has a stop on its eccentric pin to selectively engage a notch in a slider block, and prevent the slider block from moving upwardly and contacting a rear surface of the orbiting scroll. The present invention prevents this unwanted contact, and the resultant wear.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This application relates to a scroll compressor having a slider block which is driven by an eccentric pin from a drive shaft, and wherein there is a stop structure on the eccentric pin to prevent the slider block from moving upwardly beyond the eccentric pin and contacting a rear surface of the orbiting scroll.  
         [0002]     Scroll compressors have become widely utilized in refrigerant compression applications. In a scroll compressor, a first scroll member has a base and a generally spiral wrap extending from its base. The second scroll member has a base and a generally spiral wrap extending from its base. The generally spiral wraps interfit to define compression chambers. One of the two scroll members is caused to orbit relative to the other, and as it orbits the size of the compression chambers decreases and an entrapped fluid is compressed.  
         [0003]     In one type of scroll compressor, the drive mechanism for causing the scroll member to orbit includes a drive shaft driven to rotate, and having an eccentric pin extending upwardly into a slider block. The slider block is received within a rearwardly extending boss in the orbiting scroll. The eccentric pin drives the orbiting scroll through the slider block. One concern with this type of scroll compressor is that the slider block has sometimes migrated upwardly and into contact with a rear face of the base of the orbiting scroll. This has resulted in undesirable wear.  
         [0004]     It has been proposed to modify the slider block in a manner such as to have a bump or other structure on its uppermost surface to minimize the contact surface area with the orbiting scroll base, but still there is wear with the prior art.  
       SUMMARY OF THE INVENTION  
       [0005]     In the disclosed embodiment of this invention, a stop structure is provided on the eccentric pin. This stop structure prevents the slider block from moving upwardly and contacting the orbiting scroll. In one embodiment, this stop structure is a slightly enlarged upper portion of the eccentric pin which fits into a notch in the slider block. While the two may be out of contact in most cases, should the slider block begin to migrate vertically upwardly, it will contact the stop, and the stop will prevent further movement. In one embodiment, the outside dimension of the eccentric pin at the stop is less than an inside dimension of a bore through the entirety of the slider block. This will facilitate assembly of the slider block onto the slider pin.  
         [0006]     These and other features of the present invention can be best understood from the following specification and drawings, the following which is a brief description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1A  shows a prior art scroll compressor.  
         [0008]      FIG. 1B  shows another feature of the prior art scroll compressor.  
         [0009]      FIG. 1C  shows yet another feature of the prior art scroll compressor.  
         [0010]      FIG. 2A  shows the inventive scroll compressor.  
         [0011]      FIG. 2B  shows a top view of one portion of this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]     A scroll compressor  20  is illustrated in  FIG. 1A , and is as known in the art. A non-orbiting scroll  22  has a spiral wrap  23  extending from a base. An orbiting scroll  24  has a spiral wrap  25  extending from its base  27 . The orbiting scroll  24  further has a boss  26  extending away from its base  27  in an opposed direction to the wrap  25 .  
         [0013]     Refrigerant is compressed in the compression chambers defined between the wraps  23  and  25  and delivered to a discharge port  28 . Refrigerant enters the compressor housing through a section port  30 .  
         [0014]     The motor  32  drives a shaft  34  to rotate. The shaft  34  includes an eccentric pin  36  which is received within a slider block  38 . The slider block sits within the boss  26 , and between the boss and the eccentric pin  36 . When the shaft  34  is caused to rotate, the eccentric pin moves the slider block, and hence the orbiting scroll  24  to orbit. An anti-rotation coupling  37  ensures that the orbiting scroll will not rotate, but instead orbits.  
         [0015]     One problem with this prior art scroll compressor can be appreciated from  FIGS. 1B and 1C . The slider block  38  typically has an opening for receiving the eccentric pin  36  that is much larger than the pin  36 . A flat surface  54  on the eccentric pin  36  engages a flat surface  52  in the bore in the slider block  38 . When the motor is driven in a forward direction of rotation, forces within the scroll compressor cause the flat surface  54  to come into contact with the flat surface  52 . When these forces are removed, the two can move out of contact with each other.  
         [0016]      FIG. 1C  is a view generally perpendicular to the  FIG. 1B  view. As shown, the “flat” surface  54  is not truly flat, but actually has a slight barrel shape. With this prior art, there is sometimes a problem in that the slider block  38  has migrated vertically upwardly, and contacted the rear surface  60  of the base  27 . This is undesirable.  
         [0017]     The present invention is shown in  FIGS. 2A and 2B . In  FIGS. 2A and 2B , the driveshaft  34  is provided with an eccentric pin  136  that is received within a slider block  138 . The slider block  138  is provided with a notch  142  at a vertically uppermost surface. The eccentric pin  36  is provided with a stop  140  at its vertically uppermost surface. Now, when the slider block  138  begin to migrate upwardly toward the surface  60 , the stop  140  will prevent further movement. Notably, the outer dimension of the eccentric pin at the stop  140  is shown at B. This dimension is less than the dimension of the bore within the slider block  138  shown at A. In this manner, the slider block can be simply dropped onto the eccentric pin. However, when the scroll compressor is driven, and the flat surface  54  is forced against the flat surface  52 , the stop will move over and be above the notch  142 . As can be appreciated from  FIG. 2B , the notch  142  extends for a greater length than does stop  140 . This is to remove any alignment problems as the flat surfaces come into engagement.  
         [0018]     In this manner, the present invention provides a simple and effective method of preventing a slider block from contacting the rear of a base of an orbiting scroll. While a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studies to determine the true scope and content of this invention.