Patent Publication Number: US-2005140141-A1

Title: Cylindrical seal for refrigerant tube connector

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates to the use of a cylindrical shaped seal in a refrigerant line connector, preferably for an air conditioning system in a vehicle.  
      In the prior art, refrigerant lines communicate a refrigerant between the various components in a refrigerant cycle. There are several connectors that connect the lines to various components. A fluid tight seal must be provided at each of these connections. In one particular type connector, a threaded nut is threadably connected to a second connector member. In this way, a refrigerant tube may be connected to another component.  
      In the past, an O-ring seal has been provided between the nut and the housing. The O-ring seal is intended to provide the fluid tight seal mentioned above. In one particular application, a fluid tube is connected to a ferrule. The ferrule is inserted into the second connector member. The nut is then tightened onto the second connector member to squeeze the ferrule against the second connector member. The seal must seal at its outer periphery with the second connector member, and at its inner periphery with the refrigerant tube. Both of these sealing areas must be fluid tight.  
      However, due to the small sealing area of an O-ring seal, it is sometimes difficult to provide the fluid tight seal with an O-ring. In particular, an O-ring seal does require good surface conditions, without surface imperfections, flaws, etc. In many applications, and in particular in vehicle applications, the fluid connector components may have surface imperfections. Thus, O-ring seals have not always been fully acceptable for these applications.  
     SUMMARY OF THE INVENTION  
      In a disclosed embodiment of this invention, the refrigerant fluid connector is provided with a cylindrically shaped seal. The cylindrically shaped seal extends along a length that is on the order of at least twice the radial thickness of the seal. In this way, and as the seal is compressed between the components, there is a good deal of sealing surface area between the seal and the fluid components. This assures that the seal can accommodate surface imperfections, etc.  
      In addition, the cylindrical seal has two flat end surfaces that provide additional sealing contact. Thus, there is sealing at the peripheries of the seal and at the two end surfaces. Thus, an adequate seal is provided.  
      These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded view of a complex refrigerator connector system.  
       FIG. 2  is a cross-sectional view of the inventive seal.  
       FIG. 3  is a partially assembled view of a single refrigerant fluid connector incorporating the inventive seal.  
       FIG. 4  is an assembled view.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       FIG. 1  shows a fluid connector  20  for incorporating a filter between two refrigerant fluid tubes. As shown, a filter body  22  receives a bushing  24  in an inner bore  25 . A cylindrical seal  26  is received within a bore  28 . A radially inwardly extending end wall  29  extends from bore  28  to bore  25 . A ferrule  30  is positioned outwardly of the seal  28 . A refrigerant tube  31  is fixed to ferrule  30 . A nut  32  is threaded onto the outer periphery of the filter body  22 , forcing the ferrule  30  against the seal  26  to provide a fluid tight seal. Notably, the seal  26  has two flat end surfaces  48  and  50 , that abut end wall  29  and ferrule  30 , respectively. A second end cap  34  receives a bushing  36  in its bore  37 , and a seal  38  in bore  39 . A ferrule  40  again is sandwiched by a nut  42  to squeeze the seal  38 . Again, a refrigerant tube  41  is fixed to ferrule  40 . Here also is an end wall  39  and two flat end surfaces  48  and  50  on seal  38 . As shown, threads  44  and  46  connect the filter body  22  and the end cap  44 . A filter  47  is captured in chamber  60 .  
      As shown in  FIG. 2 , the seal  38  (or  26 ) is generally cylindrical and extends along a length l and for a radial thickness t. As is clear from this figure, the length l is at least twice the thickness t. In one embodiment, where the seal has an inner peripheral bore of {fraction (5/16)}, the ratio is 1:2.78. Further, the outer peripheral surface  51  of the seal  38  is not purely cylindrical, but rather has a curve which will better accommodate the inner periphery of the inner peripheral bores  28  or  39 . Flat end surfaces  48  and  50  are also formed on the seal.  
       FIGS. 3 and 4  show a somewhat distinct application wherein the bushings  36  and  24  are eliminated along with the respective bores  37  and  25 . While the connection is shown within a housing  34 , what is shown as the filter end cap from  FIG. 1 , it should be appreciated that the applications shown in  FIGS. 3 and 4  show that the present invention and its cylindrical seal do extend to other refrigerant line applications.  
      Ferrule  40  has an end surface  52  abutting end surface  48 . Further, the end surface  50  abuts an end wall  29  of the end adapter  44 . When the nut  42  is tightened onto the threads of the adapter  44 , the ferrule  40  is squeezed against the seal  38  such that sealing surfaces are provided at both end surfaces  48  and  50 , and further at the outer peripheral surface  51 . In this way, a fluid tight seal is provided. Even if there are surface imperfections within the surfaces in the adapter  44 , this seal will accommodate any such imperfections.  
      As shown in  FIG. 4 , a refrigerant tube  41  extends into the bore of the housing member  34  such that an inner end  100  of the tube is preferably axially beyond the axially innermost end  50  of the seal  38 . Thus, there is sealing contact between the seal  38  at both ends, and at both its inner and outer periphery. This combined seal provides a much greater sealing surface area than was the case with the prior art O-ring.  
      Thus, the present invention provides a seal that is better equipped to deal with imperfections in the manufactured parts. While a preferred type of refrigerant connector is illustrated, the present invention could be utilized in many other refrigerant lines. Most preferably, the present invention is used on a refrigerant line in a vehicle application.  
      The seal is preferably formed of HNBR, although other materials can be utilized.  
      Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.