Abstract:
Apparatus and a method for pre-cure application of an antenna assembly to a tire comprises the method steps: forming within a rigid core defining an interior surface of the tire a core recess complementarily configured to the antenna assembly; positioning the antenna assembly within the core recess; building an uncured carcass of the tire around the rigid core entrapping the antenna assembly within the core recess; cross-bonding the antenna assembly to the inner surface of the tire during a cure cycle; and removing the cured tire and assembly from the rigid core.

Description:
This application is a continuation-in-part of and claims priority to Ser. No. 10/777,366, filed Feb. 12, 2004 now abandoned, which is fully incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The subject invention relates generally to build apparatus and method for applying electronics to a tire for the purpose of monitoring tire condition parameters and, more specifically, to a tire build apparatus and method for incorporating an annular antenna and associated electronics into a tire. 
   BACKGROUND OF THE INVENTION 
   It is common to employ annular apparatus, including an antenna, for electronically transmitting tire or wheel identification or other data at radio frequency. The apparatus includes a radio-frequency tag, or transponder, comprising an integrated circuit chip having data capacity at least sufficient to retain identification information for the tire or wheel. Other data, such as the inflation pressure of the tire or the temperature of the tire or wheel at the transponder location, can be transmitted by the transponder along with the identification data. 
   The annular antenna is tire-mounted and transmits, at radio frequencies, data from the transponder to a reader mounted on the wheel assembly. The antenna and transponder may be incorporated into a tire during “pre-cure” manufacture of the tire. The integrity of the connection between the tire and antenna is greatly enhanced by a pre-cure assembly procedure. In practice, however, it is very difficult to do this. Both radial ply and bias ply tires undergo a substantial diametric enlargement during the course of manufacture. Bias ply tires are expanded diametrically when inserted into a curing press, which typically has a bladder that forces the green tire into the toroidal shape of the mold enclosing it. Radial ply tires undergo diametric expansion during the tire building or shaping process and a further diametric expansion during the course of curing. An annular antenna and the electronic tag associated therewith built into the tire in a pre-cure process, therefore, must endure significant stresses that can result in component failure. The electronic tag and the connection between the tag and the antenna, in particular, is vulnerable to damage from the forces imposed from pre-cure assembly to tire. 
   To avoid damaging the electronic tag or the connection between the tag and the annular antenna during the curing procedure, an alternative known approach is to assemble the tag and antenna into a separate annular apparatus for post-cure attachment to the tire. The annular apparatus may be attached to the tire after the tire is cured by adhesive or other known techniques. While such an approach avoids damaging the tag electronics during tire manufacture, adhesive attachment of the antenna and tag to a tire in a post-cure procedure has certain drawbacks. First, the procedure adds labor, and hence cost, to the manufacturing process. Secondly, the security of the attachment between the annular apparatus and the tire is dependent upon the efficacy of the adhesive system employed. Development of a suitable adhesive that is inexpensive, convenient to use, and durable enough to function throughout the life cycle of a tire has proven problematic. 
   Accordingly, a need remains for a system and method of applying tag electronics to a tire that is convenient, cost effective, and reliable. Such a procedure should further ensure the functional safety of the electronics and result in a positive electrical connection between the antenna and tag electronics. Finally, such a procedure ideally would incorporate the advantages, but avoid the shortcomings, of both the pre-cure and post-cure assembly alternatives discussed above. 
   SUMMARY OF THE INVENTION 
   Pursuant to one aspect of the invention a method for pre-cure application of an annular antenna assembly to a tire comprises the steps: forming within a rigid core defining an interior surface of the tire a core recess complementarily configured to the annular antenna assembly; positioning the annular antenna assembly within the core recess; building an uncured carcass of the tire around the rigid core entrapping the annular antenna assembly within the core recess; cross-bonding the annular antenna assembly to the inner surface of the tire during a cure cycle; and removing the cured tire and annular assembly from the rigid core. 
   According to another aspect of the invention, the annular antenna assembly may alternatively be assembled on the rigid core from components or pre-assembled off-site and transferred as a unitary assembly to the rigid core. In connection with the invention a tire mold is provided including a rigid core for the practice of the inventive method. A tire manufactured pursuant to the inventive method constitutes yet a further aspect of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described by way of example and with reference to the accompanying drawings in which: 
       FIG. 1  is a perspective view of a tire having an annular antenna assembly incorporated therein, a portion of the tire being removed for the purpose of illustration. 
       FIG. 2  is a fragmentary top plan view of a section of the annular antenna ring and transponder component. 
       FIG. 3  is a partial transverse section view of a representative tire surrounding a rigid mold core and annular antenna assembly. 
       FIG. 4  is a schematic partial radial cross section of a mold having an annular antenna assembly incorporated therein pursuant to the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring initially to  FIGS. 1 and 2 , an annular antenna assembly  10  is shown deployed within a tire  12 . The tire  12  is formed from conventional materials such as rubber or rubber composites by conventional means and may comprise a radial ply or bias ply configuration. A typical tire  12  is configured having a tread  14 , a shoulder  16 , an annular sidewall  18 , and a terminal bead  20 . An inner liner  22  is formed and defines a tire cavity  24 . The tire  12  is intended for mounted location upon an annular rim  26  having a peripheral rim flange  28  and an outer rim flange surface  30 . Rim  26  is conventionally configured and composed of a suitably strong metal such as steel. 
   An annular antenna  32  is provided and, in the preferred embodiment, embodies a sinusoidal configuration. Antenna  32  may be alternatively configured into alternative patterns or comprise a straight wire(s) if desired and may be filament wire, or cord or stranded wire. Acceptable materials for the wire include steel, aluminum, copper or other electrically conducting wire. As mentioned previously, the wire diameter is not generally considered critical for operation as an antenna and multiple strands of fine wire is preferred. The curvilinear form of antenna  32  provides flexibility and minimizes the risk of breakage during manufacture and use of the tire. 
   With continued reference to  FIGS. 1 and 2 , a tag carrier  34  of the general type described above is provided and may include means for sensing tire parameters such as pressure and temperature. Included as part of the apparatus  10  is a carrier strip of material  36  formed into the annular configuration shown. Carrier strip  36  is formed of electrically insulating, preferably semi-rigid elastomeric material common to industry such as rubber or plastic. The strip  36  is formed to substantially encapsulate the antenna wire(s)  32  and at least a portion of the tag carrier  34 . In the post manufacturing state shown in  FIG. 1 , therefore, the apparatus  10  comprises antenna  32 , tag carrier  34 , and carrier strip  36 , in a unitary, generally circular, assembly. The diameter of the apparatus assembly  10  is a function of the size of the tire  12 . The preferred location of the antenna assembly  10  on the tire is on the tire just above the rim flange  30 . Such a location minimizes stress forces on the assembly from operation of the tire and minimizes interference to RF communication between the tag and an external reader (not shown) that might otherwise be caused by the metal rim. Other mounting locations of the antenna assembly  10  on the tire, however, may be employed if desired for specific tire applications. 
   In  FIG. 3 , the tire  12  is shown in greater detail. The subject invention may be utilized in tires of various construction and size. For example, the tire  12  may be a commonly available radial passenger or light truck tire. By way of example, without any intent to limit the invention thereto, one such tire is taught by U.S. Pat. No. 6,358,346, incorporated herein by reference. The tire  12  includes a carcass  40  having a tread region  14 , a shoulder region  16 , and a sidewall region  18  extending from the shoulder  16  to an annular bead  20 . A ply structure  42  is generally provided within sidewall  18  and one or more belt plies  44 ,  46  are located at the tread region  14 . The inner liner  22  represents the interior surface of the tire and extends continuously from the bead, along the sidewall region, and across the tread region. 
   It is known to manufacture a tire using a rigid core build process. Such a process is shown and described in U.S. Pat. No. 4,985,692, incorporated herein by reference. With reference to  FIGS. 3 and 4 , in a solid core build process the tire is built upon a rigid core  48 . By “rigid”, it should be understood as “substantially non-deformable” in contrast with elastic and deformable tire building techniques. A material suitable in the formation of the rigid core  48  is steel but other suitably rigid materials may be used as desired. Additionally, while common rigid core build techniques, such as those set forth in U.S. Pat. No. 4,895,692 utilize a plurality of sliding segments in order to close the mold, the invention is not limited thereto. The invention may be used in other types of rigid cores that close in differing ways or comprise a unitary, non-segmented structure if desired. 
   A segmented rigid core mold  50  is shown in  FIG. 4  by way of example, it being understood that the invention need not be limited to the mold configuration shown. The mold  50  includes segments  52  that come into concordance with the side parts  54  via contact surfaces  56 ,  57 . Each segment also has transverse contact surfaces (not shown) which in closed position adjoin the transverse faces of the adjacent segments. The radially inner faces  58  of the core  48  come, in closed position, into contact with the corresponding faces  60  arranged in the extension  62  of each side part  54  beyond a zone  64  assuring the molding of the radially inner surface of the beads of the tire. A cavity  65  is defined between the core  48  and mold segments  52 ,  54  defined along inward toroidal surfaces to create the structure of the tire to be molded. 
   Pursuant to the invention, it is intended that the antenna assembly  10  be incorporated and bonded to a tire  12  during the cure cycle. In order to facilitate this objective, an annular groove or recess  66  is formed within an outward surface of the mold core  48 . The rigid composition of the core  48  facilitates the creation of an annular recess therein by machining or other known manufacturing techniques. The recess  66  is configured and dimensioned to receive antenna assembly  10  therein as shown in  FIGS. 3 ,  4 . The location of recess  66  within core  48  is generally preferred to be a distance nominally one inch above the tire bead, as indicated in  FIG. 3 . However, other locations may be used at the user&#39;s preference. 
   The recess  66  is provided with an enlarged socket  68  formed therein configured complementary with the transponder component  34  of the assembly. Any other geometric irregularity that is present within the assembly may be accommodated by the inclusion of a complementary recess or socket within the recess  66 . The recess  66  preferably extends in a circular path about the core  48 , however, a non-circular or irregular path may also be employed. The annular recess is sized in a depth dimension to allow the annular assembly  10  to project from the recess  66  a distance beyond the outer surface of core  48  for a purpose explained below. Insertion of the annular assembly  10  within recess  66  core  48  is preferably effected as a step preliminary to the building of the tire carcass  40  upon the core. Insertion of the annular assembly  10  into recess  66  may be accomplished manually or through the use of robotics or other known assembly methods. 
   Once the annular apparatus  10  is inserted into the recess  66  of core  48 , the tire carcass may be built upon the core beginning with the inner liner  22  in conventional fashion. The carcass this entraps and surrounds the annular apparatus within recess  66 . It will be appreciated that the annular apparatus  10  may be assembled on the core  48  from components, that is the transponder  34 , antenna wire(s)  32 , and the cover  36 . Alternatively, the assembly  10  may be assembled off-site and mounted to the core  48  as a unitary assembly. At the conclusion of the tire build procedure upon core  48 , the tire is subjected to a curing cycle in conventional fashion. 
   As a result of the vulcanization of tire  12 , the cover  36  of the assembly  10  is cross-bonded to the inner liner  22  and a strong mechanical connection is established therebetween. Protrusion of the assembly  10  from the recess  66  of core  48  enhances the cross-bonded connection between the cover  36  and the inner liner  22  and ensures that the connection is not compromised by the presence of air between the surfaces of cover  36  and inner liner  22 . Upon completion of the cure cycle, the tire  12  is removed from the mold  50  and from core  48  and includes an accurately positioned annular assembly  10  encircling the inner liner  22 . The transponder  34  is oriented within the recess  66  so that any sensor devices may be directed inward in the finished tire. For example, a pressure sensor may be directed toward and protrude into the cavity  24  of tire  12  if desired. 
   From the foregoing it will be appreciated that the subject invention satisfies the needs of the industry for a convenient, cost-effective, and reliable method for affixing an annular antenna assembly to an inner surface of the tire. The location of the annular assembly is easily selected by the user and precisely positions the assembly  10  relative to the tire  12  in a carefully controlled and repeatable manner. Moreover, no additional adhesive or hardware is required to effect the connection between the assembly  10  and tire  12 . Since the groove is configured to complement the annular assembly  10 , a positive seating of the assembly  10  within the groove  66  is possible. Additional protrusions may be incorporated within assembly cover  36  if desired by which to orient assembly  10  within groove  66 . The sides of the rigid core  48  defining groove  66  protect the annular assembly  10  during the vulcanization of the tire and damage to the assembly  10  from the forces within the tire during the cure cycle is avoided. 
   Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.