Abstract:
A method and apparatus for connecting an electronic monitoring device to a pneumatic tire includes mounting the monitoring package of the monitoring device within the body of the tire or the body of a patch and subsequently connecting the power source to the monitoring package through electrical coupling. The method allows the monitoring package to be cured within the tire or the patch at relatively high temperatures while protecting the sensitive power source from the high temperatures. The use of electrical coupling to achieve the power transfer prevents the material surrounding the monitoring package from being pierced by an element that would form the direct electrical connection. The method allows the monitoring package and its antenna to be positioned in a variety of positions on or within the pneumatic tire.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention generally relates to monitoring devices that monitor engineering conditions of pneumatic tires and, more particularly, to an apparatus and method for connecting the power supply to an electronic monitoring device mounted in a pneumatic tire. Specifically, the present invention relates to an apparatus and method for supplying power to the components of an active monitoring device after the components are mounted or cured into a pneumatic tire or mounted or cured into a patch that is then connected to a pneumatic tire. 
     2. Background Information 
     Monitoring engineering conditions of pneumatic tires is becoming increasingly desired by tire consumers who use expensive tires or who place large amounts of miles on the tires. The monitoring is preferably performed while the tires are in use on the vehicle without requiring the tires to be removed, the vehicle slowed, the tires specially positioned, or having a person position a reader in a special position to take the measurement. 
     Numerous types of monitoring devices are known in the art for performing these measurements. For instance, the monitoring device may include a pressure sensor and a temperature sensor connected to a controller having various timers, storage devices, and transmitters/receivers. The data created by the pressure sensor or temperature sensor may be stored in the storage device and later transmitted out of the tire with an antenna by the transmitter. Other types of monitoring devices may be positioned primarily outside the tire and connected to a pressure or temperature sensor through the tire&#39;s valve stem. Still other types of monitoring devices use a passive circuit embedded within the tire that is energized by inductive magnetic coupling. Further examples of monitoring devices are disclosed in U.S. Pat. Nos. 5,573,610, 5,573,611, and 5,562,787. 
     Active, self-powered monitoring devices use an antenna to transmit data from the monitoring device to a data gathering device positioned outside of the tire. One of the problems in the art is to position the antenna in the tire such that data are accurately and reliably transmitted to the data gathering device. Positioning the antenna close to the outside of the tire minimizes the amount of material through which the transmissions must pass before exiting the tire. One of the more desirable antenna positions is thus to have the antenna embedded within the tire sidewall or within a patch directly connected to the tire sidewall. The bead ring and apex filler tend to interfere with transmissions and a desirable antenna position locates the antenna above these items. Unfortunately, the areas of the tire adjacent the bead ring and the apex filler are low flex areas which are desirable mounting positions for the other components of the monitoring device. The art thus desires an invention that accommodates both positions. 
     One method of anchoring the components of the monitoring device within a pneumatic tire is to cure the monitoring device within the body of the tire. The components may also be cured within a patch that is connected to the inner liner. A significant problem with curing these elements in the body of a tire or the body of a patch is that the battery or power source used to supply power to the monitoring device is easily damaged or destroyed by the heat of the curing process. The risk of damage to the battery has prevented self-powered electronic monitoring devices from being embedded within a green tire and then cured into the tire during the green tire cure process. The damage to the battery is especially unfortunate because positioning the antenna and the monitoring device components within the tire body or within the body of a patch allows the components and antenna to be ideally positioned and secured for use within the tire. The art thus desires an apparatus and method for connecting the monitoring device to the tire by curing the components of the monitoring device within the body of the tire or the body of a patch and then subsequently connecting the battery to the components. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, the present invention provides a method of providing electrical power to a monitoring device mounted on a patch or on a pneumatic tire. The invention provides the electrical power by coupling the power source to the monitoring device such that a direct physical connection between the two elements is not required. The lack of the direct physical connection allows the monitoring device elements to be cured within the tire or the patch at relatively high temperatures and adding the power source later without penetrating any of the material surrounding the monitoring device elements. The invention thus provides multiple positions for mounting the monitoring device while protecting the integrity of the power source. 
     The invention also provides a monitoring device arrangement inside a pneumatic tire wherein the power source may be readily replaced without moving the other elements of the monitoring device. 
     The invention thus provides a combination of a pneumatic tire having a body and a monitoring device having a monitoring package; a power source; a first coupling element; and a second coupling element. The first coupling element is connected to the power source. A second coupling element is connected to the monitoring package. The monitoring device and the power source are mounted to the pneumatic tire in a position where the first and second coupling elements are aligned and spaced apart whereby power is supplied to the monitoring package from the power source by electrical coupling. 
     The invention also provides a method of mounting an electronic monitoring package to a pneumatic tire. The method includes the steps of providing a pneumatic tire having a body and providing a power source having a first coupling element connected to the power source. An electronic monitoring package is then provided having a second coupling element connected to the electronic monitoring package. The electronic monitoring package is mounted to the pneumatic tire and the power source is mounted to the pneumatic tire in a position where the first and second coupling elements are spaced apart and aligned to provide power from the power source to the monitoring package through electrical coupling. 
     The invention also includes a method of mounting an electronic monitoring package to a patch. The method includes the steps of providing a patch and providing a power source having a first coupling element connected to the power source. An electronic monitoring package having a second coupling element connected to the electronic monitoring package is then provided. The electronic monitoring package is mounted to the patch and the power source is mounted to the patch in a position where the first and second coupling elements are spaced apart and aligned to provide power from the power source to the monitoring package through electrical coupling. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiments of the invention, illustrative of the best mode in which applicant contemplated applying the principles of the invention, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended Claims. 
     FIG. 1 is a sectional view of a typical prior art pneumatic tire; 
     FIG. 2 is an enlarged sectional view of a portion of a tire sidewall wherein a monitoring device is mounted according to the concepts of the present invention; 
     FIG. 3 is a view similar to FIG. 2 showing a monitoring device mounted in another position; 
     FIG. 4 is a view similar to FIG. 2 showing a monitoring device mounted in a different position; 
     FIG. 5 is a view similar to FIG. 2 showing a monitoring device mounted in a different position; 
     FIG. 6 is a view similar to FIG. 2 showing the monitoring device mounted directly to the surface of the innerliner of the pneumatic tire; and 
     FIG. 7 is a view similar to FIG. 2 showing the use of a patch to mount the monitoring device to the innerliner of the tire. 
    
    
     Similar numbers refer to similar parts throughout the specification. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A typical prior art pneumatic tire is depicted in FIG.  1  and is indicated generally by the numeral  10 . Tire  10  includes a body  12  that includes a reinforcing cord ply  14 , at least one body ply  16 , and an innerliner  18 . Innerliner  18  includes an outer surface that faces the chamber  20  formed when tire  10  is mounted on a rim (not shown). Tire  10  also includes a pair of bead rings  22  and a pair of apex fillers  24 . 
     The first embodiment of the invention is depicted in FIG. 2 with the pneumatic tire indicated generally by the numeral  30 . Tire  30  includes many of the same body elements as tire  10  but further includes an electronic monitoring device  32  mounted to pneumatic tire  30 . Electronic monitoring device  32  includes a monitoring package  34  mounted within body  12  and a power source  36  mounted to innerliner  18 . Monitoring package  34  receives power from power source  36  through electrical coupling. Specifically, monitoring package  34  receives power through close proximity electromagnetic coupling. 
     Electronic monitoring package  34  may include a variety of components that are known in the art to monitor at least one engineering condition of pneumatic tire  30  and transmit information out of tire  30 . Electronic monitoring package  34  may include at least one sensing element that monitors or measures an engineering condition of tire  30 . Monitoring package  34  may further include a device to store the information or data gathered by the sensor, a CPU, a transmitter/receiver, and an antenna. Any of a variety of known combinations of these elements may be present in monitoring package  34  for gathering data and transmitting data out of tire  30 . In the preferred embodiment, monitoring package  34  is encapsulated with an encapsulation material  38  to protect monitoring package  34 . Encapsulation material  38  may be any of a variety of encapsulation materials known in the art such as epoxies. 
     Power source  36  is also preferably encapsulated with an encapsulation material  38 . In the preferred embodiment of the invention, power source  36  is mounted to a patch  40  that mounts power source  36  to innerliner  18 . In other embodiments, power source  36  may be mounted directly to innerliner  18  without the use of patch  40 . 
     Power source  36  is preferably in the form of a battery. The battery may be any of a variety of batteries known in the art for providing power to devices such monitoring package  34 . The battery preferably has a long life and is able to survive in the environment inside a pneumatic tire. Power source  36  may also include electronics to increase the voltage that is supplied to coupling elements thereby increasing the electric field strength. 
     In accordance with the present invention, power source  36  is in communication with monitoring package  34  through a non-direct connection. Power source  36  is coupled to monitoring package  34  through first and second coupling elements  42  and  44 . Coupling elements  42  and  44  may be coils, pads, plates, or any of a variety of other arrangements known in the art for providing field coupling between aligned and spaced elements. First coupling element  42  is in direct electrical communication with monitoring package  34  and second coupling element  44  is in direct electrical communication with power source  36 . Coupling elements  42  and  44  are arranged to be aligned and spaced apart such that power may be transferred from power source  36  to monitoring package  34 . The power transfer occurs because first coupling element  42  is placed in the field created by second coupling element  44 . A position of first coupling element  42  within the field of second coupling element  44  induces a current in second element  42  to transfer the power from power source  36  to monitoring package  34 . 
     In the embodiment of the invention depicted in FIG. 2, tire  30  is manufactured by inserting monitoring package  34  into body  12  when body  12  is being assembled. Monitoring package  34  is positioned such that body cords  14  are disposed between monitoring package  34  and the interior body ply  16 . Monitoring package  34  is placed in this position before body  12  is cured preferably at the green tire stage. Monitoring package  34  is then cured within body  12  when the green tire is cured. After body  12  is cured, power source  36  is connected to innerliner  18  such that first and second coupling elements  42  and  44  are aligned. The alignment that is required is an alignment that allows the first and second coupling elements  42  and  44  to communicate with each other and to transfer power from power source  36  to monitoring package  34 . In the embodiment depicted in FIG. 2, coupling elements  42  and  44  are disposed directly across from each other through reinforcing cord ply  14 , body ply  16 , and innerliner  18 . 
     Mounting monitoring package  34  and power source  36  in this manner allows power source  36  to be readily replaced without changing the position of monitoring package  34 . This method also allows monitoring package  34  to be positioned in a desired location within tire  30 . The use of coupling elements  42  and  44  allow monitoring package  34  to be cured within tire  30 . 
     An alternative embodiment of the invention is depicted in FIG. 3 with the tire indicated generally by the numeral  50 . Monitoring device  32  is positioned in a different position in tire  50  than in tire  30 . In tire  50 , monitoring package  34  is positioned between reinforcing cord ply  14  and body ply  16 . The arrangement of coupling elements  42  and  44  remains the same as described above and the method of building tire  50  is substantially the same as described above. 
     Tire embodiment  60  is depicted in FIG. 4 with monitoring package  34  positioned between body ply  16  and innerliner  18 . Tire  70  of FIG. 5 shows monitoring package  34  embedded within innerliner  18 . Tire  80  of FIG. 6 depicts an embodiment where monitoring package  34  is mounted to the inner surface of innerliner  18 . In each of the embodiments of FIGS. 4,  5 , and  6 , first and second coupling elements  42  and  44  are aligned and spaced apart to provide power between power source  36  and monitoring package  34 . 
     Tire  90  is depicted in FIG. 7 with monitoring package  34  embedded within a patch  92  connected to innerliner  18 . Patch  92  may be a rubber patch that is fabricated separately from body  12  of tire  90  and later connected to innerliner  18 . In another embodiment, patch  92  is an anchoring patch that is connected to innerliner  18  before body  12  of tire  90  is cured. The green tire curing process cures body  12  and anchoring patch  92  along with monitoring device  34  embedded within anchoring patch  92 . The apparatus and method of using anchoring patch  92  is disclosed and described in U.S. patent applications Ser. Nos. 09/205,931 and 09/206,273, filed Dec. 4, 1998, which are owned by the Assignee of the present application. In the other embodiment where patch  92  is an attachment patch, patch  92  is fabricated and cured separate from body  12 . In this embodiment, monitoring package  34  is connected to attachment patch  92  or embedded within attachment patch  92  before patch  92  is cured. Power source  36  may be attached to patch  92  before patch  92  is connected to innerliner  18  or after patch  92  is connected to innerliner  18 . 
     Accordingly, the improved method of providing electrical power to an embedded electronic device in a tire using close proximity electromagnetic coupling apparatus is simplified, provides an effective, safe, inexpensive, and efficient device which achieves all the enumerated objectives, provides for eliminating difficulties encountered with prior devices, and solves problems and obtains new results in the art. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirement of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described. 
     Having now described the features, discoveries, and principles of the invention, the manner in which the method of providing electrical power to an embedded electronic device in a tire using close proximity electromagnetic coupling is constructed and used, the characteristics of the construction, and the advantageous new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts, and combinations are set forth in the appended claims.