Patent Publication Number: US-2011061307-A1

Title: Weather Strip for a Door of a Motor Vehicle and Method of Making Same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT International Application No. PCT/EP2009/004107, filed Jun. 8, 2009, which claims priority under 35 U.S.C. §119 from German Patent Application No. DE 10 2008 027 877.7, filed Jun. 11, 2008, the entire disclosures of which are herein expressly incorporated by reference. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to a weather strip (seal) for a door of a motor vehicle. 
     Weather strips are known which are arranged on a window frame of a door and have a sealing lip. The weather strips rest on an outer surface of a door opening of a vehicle body. The sealing lip may rest directly on the vehicle body section of the door opening. 
     In another specific embodiment, a trim strip or the like is mounted on the door opening. The sealing lip of the window frame weather strip rests on the outer surface of the trim strip. Noise generated, for example, by a “stick-slip” effect may occur between the outer surface of the door opening and the sealing lip of the window frame weather strip. 
     A weather strip for a vehicle frame structure is known from WO 2004/082974 A1, where the functional surfaces of the weather strip are coated with a sliding varnish or are flock-coated in order to avoid a “stick-slip effect”. 
     It is an object of the invention to create a weather strip for a door of a motor vehicle whereby noise generation is minimized. 
     This and other objects are achieved by a weather strip according to the invention for a door of a motor vehicle, the weather strip being arranged on a window frame of the door. The weather strip has a sealing lip which, in a closed condition of the door, rests against an outer surface of a body component of the motor vehicle. The outer surface of the sealing lip of the weather strip has a double coating consisting of a flock coat and a sliding varnish. This double coating reduces the coefficient of friction and thus a “stick-slip effect” during the closing of the door and when driving on uneven roads, which situation causes a relative movement between the door and the vehicle body. 
     In an advantageous embodiment, the outer surface of the sealing lip is adjoined by a flock coat. The flock-coated outer surface of the sealing lip is additionally coated with a sliding varnish layer. 
     A thickness t of the sliding varnish layer is advantageously in a range from 13 μm&gt;t&gt;4 μm. 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a lateral view of a passenger car; 
         FIG. 2  is a cross-sectional view taken along Line I-I in  FIG. 1 , wherein, in a closed condition of the door, a sealing lip of a window frame weather strip rests directly on a vehicle body section of a door opening; and 
         FIG. 3  is a cross-sectional view taken along Line I-I in  FIG. 1  of another embodiment, wherein a trim strip is arranged on a door opening, a sealing lip of a window frame of a door resting on the trim strip in the closed condition of the door  1 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a lateral view of a motor vehicle  1 . A forward door opening  3  and a rearward door opening  4  are constructed in a body  2  of the motor vehicle  1 . A front door  5  and a rear door  6  are each hinged in the door openings  3 ,  4 , respectively, in a known manner. 
     The respective door  5 ,  6  has a door body  7 ,  8  as well as a window frame  9 ,  10  in each case constructed at the respective door body  7 ,  8 . One window pane  11 ,  12  respectively is displaceably arranged in the respective window frame  9 ,  10 . Additionally, a rear window pane  13  is arranged in the window frame  10  at the rear door  6 , which rear window pane  13  is, for example, arranged in a fixed or swivelable manner. 
     As illustrated in  FIG. 2 , a window frame weather strip  15  is fastened to a forward upper flange  14   a  of the window frame  9 . The window frame weather strip  15  has a sealing lip  16 . In the closed condition  18  of the door  5 , the sealing lip  16  rests with an outer surface  17  against an outer surface  19  of a roof frame section  20  of the vehicle body  2 . 
     The cross-sectional view of  FIG. 3  differs from the cross-sectional view of  FIG. 2  essentially in that an additional trim strip  21  is arranged on the roof frame section  20 . A sealing lip  23  of a window frame weather strip  24  rests against an outer surface  22  of the trim strip  21 . The window frame weather strip  24  is fastened to a forward upper flange  14   b  of the window frame  9 . In the closed condition  18  of the door  5 , an outer surface  25  of the sealing lip  23  rests against the outer surface  22  of the trim strip  21 . 
     The outer surface  17  of the sealing lip  16  and the outer surface  25  of the sealing lip  23 , respectively, have a double coating. In an exemplary embodiment, a flock coat is first applied in a known manner to the respective outer surface  17 ,  25  of the sealing lip  16 ,  23 . Subsequently, a further coating takes place by use of a sliding varnish. 
     In one embodiment, the flocks used for the flock coating have a length l of 0.4 mm&lt;l&lt;1.2 mm. The flocks are produced, for example, of polyoxymethelene (POM) or polyamide (PA). In an embodiment, the thickness t of the applied sliding varnish layer is at 13 μm&gt;t&gt;4 μm. 
     The layer thickness t of the sliding varnish depends on different parameters. These include, among others, the nature of the outer surface  19  of the roof frame section  20  and of the outer surface  22  of the trim strip  21  respectively. Also, in the case of a powder-coated outer surface  22  of the trim strip  21 , which has an increased coefficient of friction, the double coating of the sealing lip  16 ,  23  results in the avoidance of a “stick-slip” effect. 
     Tests have shown that the double coating of the outer surface  17 ,  25  of the sealing lip  16 ,  23  leads to a continuous rise in strength along the predefined path during the closing of the door and the resulting location of the outer surface  17 ,  22  of the sealing lip  16 ,  23 . 
     By use of the double coating of the outer surface  17 ,  25  of the sealing lip  16 ,  23 , an adherence of the outer surface  17 ,  25  of the sealing lip  16 ,  23  on the outer surface  19  of the roof frame section  20  or on the outer surface  22  of the trim strip  21  is avoided for the lifetime of the sealing lip  16 ,  23 . This also prevents the generation of noise. 
     The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.