Patent Abstract:
A method of securing a tire pressure-monitoring device to a vehicle wheel includes the steps of welding a bracket within a tire wheel well. The bracket assembly includes a weld surface that corresponds to a surface on the wheel rim. The weld surface includes a common curvature that matches the surface of the wheel and also includes a material compatible with welding to the wheel rim.

Full Description:
[0001]     The application claims priority to U.S. Provisional Application No. 60/530,390, which was filed on Dec. 17, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     A tire pressure-monitoring device provides information on current tire conditions. The conditions within the tire that are monitored by the device include air pressure, temperature and other characteristics indicative of current tire conditions. The tire pressure-monitoring device is most often included as a part of the tire air valve assembly. In this way the tire pressure-monitoring device is assembled along with the tire air valve into an opening provided within a wheel rim. Such installation techniques require that the wheel rim be fitted with a counter balance to offset the imbalance created by the added weight of the tire pressure monitoring system on the valve stem. Further, the joint between the valve stem body and a wheel rim is susceptible to corrosion due to electrolytic reactions caused by brake dust against the junction between the valve stem and the wheel rim.  
         [0003]     It is also known to secure a tire pressure monitoring device within the tire well of a wheel rim with a strap that extends about the circumference of the wheel. This strap is tightened down against the wheel and provides for the mounting of the tire pressure-monitoring device independent of the valve stem. The strap is most often a metal strap that is drawn tight by mechanical fastening means.  
         [0004]     As appreciated, such methods of mounting a tire pressure-monitoring device create certain challenges to assembly and durability of a wheel assembly. It is therefore desirable to design a mounting configuration for a tire pressure-monitoring device that does not adversely affect tire balance and also that provides a durable reliable connection. Further, it is desirable to develop a method for securing a tire-monitoring device within a wheel that is cost effective to assembly.  
       SUMMARY OF THE INVENTION  
       [0005]     The example tire pressure monitoring mounting device of this invention includes a bracket that is welded to an inner surface of a wheel rim.  
         [0006]     This invention includes a method of securing a bracket or a tire pressure monitoring device within a tire well of a rim utilizing a friction welding technique. The method includes a step of holding a bracket assembly against a wheel rim in a desired location. The bracket assembly includes a weld surface that corresponds to a surface on the wheel rim. The weld surface includes a common curvature that matches the surface of the wheel and also includes a material compatible with welding to the wheel rim.  
         [0007]     The wheel is rotated relative to the bracket assembly at a speed that combined with a downward force will generate heat both in the bracket and in the wheel to create a weld. Once a sufficient amount of heat has generated by the relative rotation between the bracket and the wheel. The wheel is stopped with the bracket in a desired location. An added force is exerted on the bracket to complete the weld. Once the bracket and wheel have cooled the bracket is welded and becomes an integral part of the wheel assembly.  
         [0008]     Once the bracket is secured to the wheel assembly the tire pressure monitoring device can be attached to the bracket. The bracket can comprise any type of clip that corresponds to the features of the tire pressure-monitoring device.  
         [0009]     Accordingly, the method and assembly of this invention provides a robust, reliable, and cost effective way of securing a tire pressure-monitoring sensor within a wheel assembly.  
         [0010]     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  
       [0011]      FIG. 1  is a cut away view of a tire assembly including a tire pressure-monitoring device mounted according to this invention.  
         [0012]      FIG. 2  is a cross-sectional view of the tire assembly with the tire pressure-monitoring device mounted according to this invention.  
         [0013]      FIG. 3  is a cross-sectional view of the tire pressure-monitoring device mounted to a wheel according to this invention.  
         [0014]      FIG. 4  is a schematic view of an attachment means between the bracket assembly and tire pressure-monitoring device.  
         [0015]      FIG. 5  is another top view of a tire pressure-monitoring configuration according to this invention.  
         [0016]      FIG. 6  is a cross-sectional view of another tire pressure monitoring device mounted to a wheel according to this invention.  
         [0017]      FIG. 7  is a block diagram illustrating a method of securing and welding a tire pressure monitoring attachment device to a wheel assembly according to this invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Referring to  FIG. 1 , a wheel assembly  10  includes a tire  12  mounted to a rim  14 . A bracket  18  is mounted to an inner surface  20  of the rim  14  and supports a tire pressure monitoring assembly  16 . The bracket  18  is welded to the inner surface  20  of the rim  14 . The bracket  18  is friction welded to the inner surface  20 . Although friction welding is shown and discussed it is within the contemplation of this invention to secure the bracket  18  to the inner surface  20  of the wheel rim  14  by any welding means known to a worker versed in the art.  
         [0019]     Referring to  FIG. 2 , the tire  12  is mounted to the rim  14  and defines a tire well  26 . The tire well  26  is a portion of the rim  14  between the outermost walls that support attachment of the tire  12 . The specific shape of the tire well  26  is as commonly known. The wheel inner surface  20  of the wheel rim  14  includes a surface that corresponds to the desired configuration of the wheel assembly  10 . That is, the inner surface  20  is not a planar surface in that there are specific curved surfaces and contours that are required to provide for mounting of the tire  12  and to accommodate mounting configurations for the wheel assembly  10 .  
         [0020]     The bracket  18  secures the tire pressure-monitoring assembly  16  to a surface of the wheel rim  14  that is offset from a centerline. The specific location of the tire pressure monitoring assembly  16  is provided to minimize any imbalance that may be caused by the additional weight and mass of the tire pressure monitoring assembly  16 .  
         [0021]     The tire pressure monitoring assembly  16  includes a plurality of electronics  24 . Typically, the electronics  24  include sensors for sensing pressure and temperature within the tire and a transmitter for transmitting signals indicative of conditions within the tire  12  to an external controller. The specific configuration of the tire pressure monitoring assembly  16  is as known. A worker skilled in the art with the benefit of this disclosure would understand that many different tire pressure-monitoring devices are within the contemplation of this invention.  
         [0022]     The bracket  18  is welded to the rim  14  along the inner surface  20 . The tire pressure-monitoring assembly  16  is in turn attached to the bracket  18 . In one example, the bracket  18  is friction welded to the wheel rim, however, other welding methods such as spot welding, brazing and laser welding are within the contemplation of this invention.  
         [0023]     Referring to  FIG. 3 , an enlarged cross-sectional view of the tire pressure monitoring assembly  16  is shown mounted to the bracket  18 . The tire pressure monitoring assembly  16  includes a housing  22  that is filled with a potting material  28  that supports and protects the electronics  24 . Bracket  18  includes a clip  30  that holds the housing  22  in its desire location. The bracket  18  also includes a weld segment  32 . The weld segment  32  corresponds with the inner surface of the wheel rim  14  and provides for welding of the bracket  18  to the inner surface  20  of the wheel rim  14 .  
         [0024]     In a friction welding process, a force schematically indicated by arrows  50  is exerted downwardly on the bracket  18  to hold the bracket  18  against an inner surface  20  of the wheel rim  14 . The wheel rim  14  is then rotated at a speed that generates sufficient heat both in the bracket  18  and in the localized surfaces of the wheel rim  14  that correspond to the position of the bracket  18 . Upon the sufficient generation of heat between the bracket  18  and the inner surface  20  the wheel rim  14  is stopped. An additional force is exerted upon the bracket  18  downwardly to force the bracket  18  against the wheel rim  14  to complete the friction welding operation. Once the bracket  18  and wheel rim  14  has cooled the bracket  18  will be welded to the wheel rim  14  and secured there in place.  
         [0025]     The tire pressure monitoring assembly  16  can than be clipped into the bracket  18  by way of the clip  30 . The clip  30  as is shown in  FIG. 3  comprises a lip portion  31  and tab portion  33 . The lip portion  31  and tab portion  33  cooperate with features of the housing  22  to secure the tire pressure monitoring assembly  16  to the bracket  18 . A specific configuration of a clip  30  for securing the housing  22  to the bracket  18  is shown in  FIG. 3 . A worker versed in the art with the benefit of this disclosure would understand that other clip configurations as are known are also within the contemplation of this invention.  
         [0026]     Referring to  FIG. 4 , another bracket  15  is illustrated that includes clip  33 . The clip  33  includes two elongated arms  35  that provide a tensile force to secure the housing  22 . The housing  22  includes flat surfaces that correspond with the clip  33 . The housing  22  is simply slid under the clip  33  and held there in place.  
         [0027]     Referring to  FIG. 5 , another tire pressure monitoring assembly  16  is illustrated along with another bracket  17 . The bracket  17  that includes a tab  36  that corresponds with slot  34  disposed within the housing  22 . The housing  22  is then slid onto and secured by the tabs  36 . The tabs  36  compress to allow the tabs  36  to fit through the slot  34  and then expand outwardly from the slot  34  to prevent removal of the housing  22 .  
         [0028]     Referring to  FIG. 6 , another bracket  19  according to this invention is illustrated that includes the tire pressure monitoring assembly  16 . In this embodiment the tire pressure monitoring assembly  16  is integrally formed within the bracket  19 . The bracket  19  defines a cavity into which the electronics  24  are placed. Potting  28  is then utilized to fill the cavity in which the electronics  24  is placed to support the electronics and protect them. The bracket  18  is then friction welded to the wheel rim  14 . In this way no clip configuration is required in that the tire pressure-monitoring device sticks permanently to the wheel rim  14 . Further, the number of component parts is reduced. In this embodiment, the bracket  19  includes the weld segment  32  and also finds portions of the housing  22  that define the space into which the electronics  24  for the tire pressure-monitoring assembly  16  are secured.  
         [0029]     Referring to  FIG. 7 , a block diagram schematically illustrating the method of securing the tire pressure monitoring assembly  16  of this invention is shown. In a first step  40  indicated and illustrated at  42  a bracket  18  is placed and held under a force  50  against the surface of the wheel rim  14 . Location step  44  includes the step of applying a force on the bracket  18  against the rotating rim  14  to generate heat in the bracket  18  and in the wheel rim  14 . The interface is schematically indicated and shown at  45  between the wheel rim  14  and bracket  18  that generates sufficient heat to melt the materials in both the bracket  18  and the rim  14  to a point as to enable a bond to be formed between the two.  
         [0030]     Once a desired amount of heat has been generated both in the bracket  18  and in the wheel rim  14 , the rim  14  is stopped at a desired mounting location on the rim  14 . This location is pre-determined such that the tire pressure monitoring assembly  16  will be placed in a location on the wheel that provides and minimizes potential counter balance requirements. Once the rim  14  has stopped rotating an additional force  51  is added to press the bracket  18  against the wheel rim  14 . The additional forces as indicated at step  46  provide for adhesion between wheel rim  14  and bracket  18 . The specific rotational speed and forces required to build the friction and generate the heat required are as known to a worker skilled in the art. A worker skilled in the art with the benefit of this disclosure would understand how to apply friction-welding techniques to the mounting of the tire pressure-monitoring bracket  18  to the wheel rim  14 . Once the bracket  18  has been bonded and adhered to the rim  14  the tire pressure monitoring assembly  16  is mounted to the bracket  18 . Alternatively, as is shown in  FIG. 6 , the electronics are already mounted within the bracket  18  and therefore is already mounted in the proper location.  
         [0031]     Accordingly, the method in the place of this invention provides an effective reliable and cost-effective means of securing a tire pressure monitoring system within a wheel assembly.  
         [0032]     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.

Technology Classification (CPC): 1