Abstract:
A wire sealing assembly provides sealing to a panel opening member with grommet housing, a wire seal, and a panel seal. The grommet housing has a cylindrical wall defining a wire receiving area. A wire alignment tab extends from the cylindrical wall into the wire receiving area and a locking projection extends outward from the cylindrical wall. One or more wires are positioned on the wire alignment tab and an overmolded wire seal is applied surrounding the wire(s) substantially filling the wire receiving area and being chemically bonded to the cylindrical wall. A panel seal is applied between the grommet hosing and a panel opening member and the locking projection serves to secure the grommet housing to the panel opening member.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention is related to a wire sealing assembly for sealing a wire within an opening of a sealed enclosure.  
       BACKGROUND  
       [0002]     Electrical distribution systems, for example in an automotive application, may utilize a wiring harness, which is manufactured as a sub-assembly. Such a wiring harness may include a plurality of electrical connectors for receiving electrical signals and for distributing those electrical signals to various components within a system. The wiring harness may ultimately be used in applications were sealing of each electrical connector is required to meet environmental constraints. Additionally, the wiring harness may be required to pass through openings within sealed enclosures without the use of an electrical connector located between the inside and the outside of the sealed enclosure. Grommets are typically used for sealing wires within an opening for these applications. The grommet may be a split grommet which is wrapped around the wire or a plurality of wires and then compressed either by friction fit within the opening or by use of a mechanical securing device.  
         [0003]     In certain applications, for example in a vehicle, such grommets are exposed to extreme temperature cycling which causes deterioration and loss of a seal. What is needed is an improved sealing arrangement for passing wires into or out of a sealed enclosure.  
       SUMMARY  
       [0004]     A sealing assembly includes a grommet housing having a cylindrical wall defining a wire receiving area. A wire alignment tab extends from the cylindrical wall into the wire receiving area and a locking projection extends outward from the cylindrical wall. At least one wire is positioned on the wire alignment tab and an overmolded wire seal surrounds the wire substantially filling the wire receiving area and being chemically bonded to the cylindrical wall. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     The invention will now be described in greater detail with reference to the accompanying figures of which:  
         [0006]      FIG. 1  is a perspective view of the wire sealing assembly according to the present invention.  
         [0007]      FIG. 2  is a cut away perspective view of the wire sealing assembly of  FIG. 1 .  
         [0008]      FIG. 3  is a bottom perspective view of the wire sealing assembly of  FIG. 1 .  
         [0009]      FIG. 4  is a perspective view of the grommet housing used in the wire sealing assembly of  FIG. 1 .  
         [0010]      FIG. 5  is a perspective view similar to that of  FIG. 1  for an alternate wire sealing assembly according to the present invention.  
         [0011]      FIG. 6  is a cross sectional view taken along the line  6 - 6  of  FIG. 5 .  
         [0012]      FIG. 7  is an exploded perspective view showing the underside of the wire sealing assembly of  FIG. 5 .  
         [0013]      FIG. 8  is a perspective view similar to  FIG. 7  showing the underside of an assembled wire sealing assembly.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]      FIGS. 1-4  show a first embodiment of a wire sealing assembly  10  according to the present invention having a panel opening member  20 , a grommet housing  30 , a wire seal  40 , and a panel seal  50 . Each of these major components will now be described in greater detail.  
         [0015]     Referring first to  FIG. 2 , the panel opening member  20  has a first panel surface  22  opposite a second panel surface  24 . A shoulder  26  extends outward from the second panel surface  24  to form a peripheral recess  27 . A seal engaging surface  28  extends along the peripheral recess  27  from the shoulder  26  inward to an extension wall  29 . The extension wall  29  extends from the seal engaging surface  28  further outward from the second panel surface  24  to a free end  31 . The shoulder  26 , seal engaging surface  28  and extension wall  29  define a passageway  23 . As best shown in  FIG. 3 , channels  32  are formed in the extension wall  29  and project outward therefrom between the seal engaging surface  28  and the free end  31 . The free end  31  is profiled to have a tapered surface  36  which extends from a locking recess  38  around a portion of the free end  31  to a back stop  34  positioned near the end of the channel  32 .  
         [0016]     Referring now to  FIG. 4 , the grommet housing  30  will be described in greater detail. The grommet housing  30  is formed of an insulative material and is a generally cylindrical assembly having a cylindrical wall  42 , which is sized to fit within the passageway  23 . Suitable materials for the grommet housing  30  include but are not limited to Polybutylene terephthalate (PBT), polypropylene, Acrylonitrile-butadiene-styrene (ABS) or nylon. A flange  44  extends outward from the cylindrical wall  42  adjacent a first end  45 . The flange  44  features a pair of actuating shoulders  46  extending upward from a top surface  47  of the flange  44 . The actuating shoulders  46  are sized to be gripped by fingers or a suitable actuating tool. Behind each actuating shoulder  46  is an optional support member  49 . The optional support members  49  may take various shapes but are shown in this embodiment to have a tapered top surface beginning behind the actuating shoulder  46  and extending downward to the top surface  47  of the flange  44 . A wire alignment tab  33  extends inward from the cylindrical wall  42  into a wire receiving area  41 . Wire receiving recesses  35  are formed along an edge of the wire alignment tab  33  and are centrally located within the wire receiving area  41 . Locking projections  48  extend outward from the cylindrical wall  42  at an end opposite the flange  44  and first end  45 . As best shown in  FIG. 2 , the wire seal  40  substantially fills the wire receiving area  41 . The wire seal  40  is formed of a suitable material which is chemically bondable or otherwise secured to the inner surface of the cylindrical wall  42 . A suitable matierials for the wire seal  40  includes but is not limited to a thermoplastic elastomer such as Santoprene. In this embodiment, the wire seal  40  is formed of a thermoplastic elastomer which is chemically bondable to the insulative material of the cylindrical wall  42 , namely, PBT of the grommet housing  30 . It should be understood by those skilled in the art that the thermoplastic material for the wire seal  40  is selected based on it ability to chemically bond to the insulative material of the cylindrical wall  42  and that both materials are selected based on the environmental constraints where the wire sealing assembly  10  shall be installed. The wire seal  40  is applied by an over molding process wherein it is overmolded onto wires  43  passing through the wire receiving area  41 .  
         [0017]     As shown in  FIG. 2 , a panel seal  50  which, in this embodiment, is formed of a silicone rubber material is applied between the under side of the flange  44  and the seal engaging surface  28 . The panel seal  50  is generally circular and is sized to fit on the seal engaging surface  28 . The panel seal  50  is profiled to have a series of bumps  52  formed along opposing surfaces. The bumps  52  engage the flange  44  on one side and engage the seal engaging surface  28  on the other side. The panel seal  50  is compressible between the flange  44  and seal engaging surface  28 . It should be understood by those skilled in the art that although the panel seal  50  is shown in this embodiment to have a series of bumps  52  which are compressible, other seals having different constructions and being formed of alternate materials which are compressible between the flange  44  and seal engaging surface  28  may be substituted.  
         [0018]     In assembly, wires  43  are first inserted into the wire receiving area  41 . Each wire  43  is then positioned within a respective wire receiving recesses  35 . Wires  43  are then overmolded to form the wire seal  40  which substantially fills the wire receiving area  41 . The panel seal  50  is applied to the seal engaging surface  28 . The wire and grommet housing assembly is then inserted into the panel opening member  20  such that the locking projections  48  pass through the channels  32  until they exit at the free  31  near the back stop  34 . The actuating shoulders  46  are then engaged by a suitable tool or alternatively by fingers to rotate the grommet housing  30  such that the locking projection  48  rides along the tapered surface  36  and engages the locking recess  38 . The panel seal  50  is compressed as the locking projections  48  move along the tapered surfaces  36  drawing the grommet housing  30  further into the panel opening member  20 . In order to remove the grommet housing  30 , it is first urged downward toward the free end  31  against the panel seal  50  to release the locking projections  48  from the locking recesses  38  and is then rotated back along the tapered surface  36  to the back stop  34 . It may then be removed from the panel opening member  20  as the locking projections  48  pass through the channels  32 .  
         [0019]     An alternate wire sealing assembly  110  according to the present invention will now be described with reference to  FIGS. 5-8 . The wire sealing assembly  110  has a panel opening member  120  and a grommet  130  which incorporates the features of the grommet housing  30  and the wire seal  40 . The same panel seal  50  may be used in this alternate embodiment. Each of the major components will now be described in greater detail. Referring first to  FIGS. 5, 6 , and  7 , the panel opening member  120  features a similar first panel surface  22  and opposite second panel surface  24 . A similar shoulder  26  extends outward from the second panel surface  24  to form a similar peripheral recess  27  and seal engaging surface  28 . A modified extension wall  129  extends from the seal engaging surface  28  outward from the second panel surface  24  to a free end  131 . The free end  131  is profiled to have a plurality of locking recesses  138  formed adjacent tapered surfaces  136 . Back stops  134  are formed adjacent each locking recesses  138 . Channels  132  extend along the modified extension wall  129  and have an end located near a respective back stop  134 .  
         [0020]     The grommet  130  of this alternate embodiment is modified to eliminate the need for a separate grommet housing  30  and wire seal  40 . The grommet  130  features a flange  142  which extends generally parallel to the first and second panel surfaces  22 ,  24 . Vertical actuating shoulders  149  extend upward from the flange  142 . Referring to  FIG. 7 , an inside vertical wall  144  extends downward from the flange  142 . The inside vertical wall  144  includes first locking projections  146  extending outwardly from a central region and a second locking projection  148  also extending outward from a central region. Wires  43  are positioned within the central region. Openings  145  are also located in the central region adjacent the wires  43 . A plurality of wire sealing sections  152  are integral with and located on the flange  142  to pass through both the inside vertical wall  144  and the actuating shoulders  149 . These wire sealing sections  152  are formed by over molding wires  43 . The first and second locking projections  146 ,  148  are aligned with channels  132  so that the grommet  130  may be inserted into the panel opening member  120  as will be described below. A seal  50  is similarly provided between the underside of the flange  142  and the seal engaging surface  28  within the peripheral recess  27 .  
         [0021]     In assembly, wires  43  are overmolded to form the grommet  130 . Wire clamps included in the mold (not shown) hold the wires  43  in place in the vicinity of the openings  145  as molten material is flowed into a mold. After the grommet  130  is removed from the mold, the panel seal  50  is applied to seal engaging surface  28 . The grommet  130  is then inserted into the panel opening member  120  such that locking projections  146 ,  148  pass through the channels  132  until they exit at the free ends  131 . The vertical actuating shoulders  149  are then engaged to rotate the grommet  130  such that the locking projections  146 ,  148  ride along the tapered surfaces  136  and lock into locking recesses  138  as best shown in  FIG. 8 . The panel seal  50  is compressed as the locking projections  146 ,  148  move along the tapered surfaces  136  drawing the grommet  130  further into the panel opening member  120 .  
         [0022]     The wire sealing assembly  10 ,  110  advantageously provides accurate positioning of the wires  43  and an effective seal between the wires and the panel opening member  20 ,  120 . These features result in improved sealing of the arrangement especially in harsh temperature cycling environments  
         [0023]     The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.