Abstract:
An adaptive tire employable by a vehicle traveling upon a surface, including a releasable element operable to selectively modify a performance characteristic of the tire, such as traction, and methods of enhancing the performance of a tire by selective introduction of a substance.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present disclosure generally relates to tires, such as automobile tires, and more particularly to methods of enhancing tire performance using releasable elements. 
         [0003]    2. Discussion of Prior Art 
         [0004]    Properly functioning tires are important to ensure health and safety during the operation of a vehicle. Among the most important performance characteristics associated therewith is traction, which is the kinematic friction force defined by the tire and road (or otherwise surface) when the vehicle is in motion. It is appreciated that a minimum amount of traction is necessary to dynamically absorb gravitational, centripetal, and/or braking forces. Concernedly, however, it is well known that various ambient and inherent conditions have adverse impacts upon traction, including, for example, low tire tread (in certain instances), hyper-inflated tires, and the presence of rain, snow, ice, and other foreign substances. Even in the absence of these conditions, the amount of traction necessary varies under differing vehicular conditions (e.g., loading, speed, incline slope, etc.). Despite the need to maintain proper traction under varying conditions, conventional tires typically present non-adaptive solutions. 
       BRIEF SUMMARY 
       [0005]    The present invention concerns an adaptive or “smart” tire that is able to autonomously adjust a performance characteristic, and primarily the traction defined between the tire and riding surface, in response to an ambient or inherent condition. As such, the invention is useful for expanding the range of safe operation. The invention, especially in an automotive setting, is further useful for increasing fuel economy through the selective increase in traction. 
         [0006]    In the instant disclosure, the inventive tire is employable by a vehicle traveling upon a surface, comprises a first structural component configured to engage the surface along a face, and is adapted to selectively change the performance characteristic. With respect to the latter, the tire is formed of at least one releasable element inter-engaged with the component. The releasable element is in operative communication with, and configured to be selectively released, so as to modify the performance characteristic. In a second aspect of the invention, a method of adjusting a performance characteristic, such as traction, includes the release of at least one element onto the tire or into the contact patch. Various configurations of the smart tire, including suitable releasable substances, are provided. 
         [0007]    The above described and other features are exemplified by the following figures and detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures of exemplary scale, wherein: 
           [0009]      FIG. 1  is an elevation of a vehicle traveling upon a surface and having smart tires and/or defining substance releasing orifices, in accordance with a preferred embodiment of the invention; 
           [0010]      FIG. 2  is a perspective view of a smart tire having embedded releasable elements, in accordance with a preferred embodiment of the invention; 
           [0011]      FIG. 3  is a cross-sectional view of a smart tire, particularly illustrating the releasable elements and structure of the tire, including heating elements interengaged with the releasable elements, in accordance with a preferred embodiment of the invention; 
           [0012]      FIG. 4   a  is a partial elevation of a smart tire having a plurality of releasable microcapsules carrying a performance enhancing substance impregnated within the tire material, wherein a first quantity of substance has been released, in accordance with a preferred embodiment of the invention; 
           [0013]      FIG. 4   b  is an elevation of the tire shown in  FIG. 4   a , wherein a larger quantity of substance has been released; and 
           [0014]      FIG. 4   c  is an elevation of a smart tire having a plurality of releasable microcapsules carrying first and second agents impregnated within the tire material, wherein a quantity of each agent has been released and the released agents have combined to form the performance enhancing substance adjacent the roadway surface, in accordance with a preferred embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The present invention concerns plural methods of enhancing tire performance generally utilizing releasable elements, and smart tires  10  employing the same. In general, the inventive tires  10 , described and illustrated herein are operable to selectively release a performance enhancing substance  12  under desired ambient and inherent vehicular conditions ( FIGS. 1-4   c ). The advantages and benefits of the invention may be used in various types of transportation vehicles (e.g., with respect to bicycles, aviation, etc.), but is more particularly suited for use with an automotive vehicle  14  (e.g., motorcycle, car, truck, SUV, all-terrain vehicle, etc.), wherein said vehicle  14  travels upon a surface  16 . 
         [0016]    As best shown in  FIGS. 2 and 3 , the inventive modifications are adapted for use with an otherwise conventional elastomeric (e.g., synthetic and/or natural rubber) tire that defines an interior region when mounted upon a wheel  18 . A valve assembly  20  enables compressed air to enter the region, so as to inflate the tire  10  to an operative state. The tire  10  itself is formed by a plurality of structural components, including first and second opposite sidewalls  22  interconnected by a treadwall  24 . More particularly, and as shown in  FIG. 3 , the tire  10  may be of the type having a treadwall  24  consisting essentially of a central rib  26 , and tread elements  28  (or “blocks”). The tread elements  28  define grooves  28   a  and sipes  28   b  that cooperatively from a tread pattern and depth that contribute to the traction. The treadwall  24  preferably presents chamfered or rounded lateral shoulders  30  that transition into the outer periphery of the sidewalls  22 . 
         [0017]    Underneath the tread elements  28 , a layer of reinforcing belts or piles  32  typically formed of steel, add structural stability and puncture resistance to the treadwall  24 . Cap piles  34  are optionally provided intermediate the elements  28  and reinforcing belts  32  for added security. The sidewalls  22  provide lateral stability to the tire  10  and together with the compressed air transfers the weight of the vehicle  12  to the surface  14 . As shown in  FIG. 1 , it is appreciated that the sidewalls  22  undergo deformation as the tire  10  rolls. Finally, bead bundles  36  typically consisting of a plurality of wires run within bead chaffers defined along the inner radius of the tire  10 . The bundle  36  provides structural strength and stiffness at this location, which among other things enables the tire  10  to stay mounted onto the wheel  18 . Finally an interior liner  38  further protects the tire  10 . It is appreciated that the afore-described tire  10  is described for exemplary purposes only, such that the present invention may be used with various tire configurations not described herein. 
         [0018]    In a preferred embodiment of the invention, rubber compound formulations are used to construct the tread elements  28 , and include a microencapsulated performance enhancing substance  12 . The formulations and geometric configurations of the elements  28  are cooperatively configured such that the substance  12  releases rapidly under predetermined passive conditions. For example, the substance  12  may be released under extreme acceleration, hard cornering, or severe braking.  FIGS. 4   a - c  schematically show a plurality of microcapsules  40  disposed at or near the face of a tread element  28 , wherein a portion of which have been breached; however, it is appreciated that a singular void (not shown), lesser plurality of longitudinal channels (also not shown), or other configurations may be used to store the substance  12 . 
         [0019]    Once released, the substance  12  is configured to rapidly act to increase traction between the tire  10  and roadway surface  16 , and in one embodiment is chemically reactive with the tread material and/or surface  16 . The microcapsules  40  and tread elements  28  may be cooperatively configured so that the substance  12  is released externally, or just under the exterior face of the elements  28 . It is appreciated that the microcapsules  40  may be formed by the tire material itself. That is to say, the substance  12  may be store in a plurality of pockets defined at or near the face of the treadwall  24 . 
         [0020]    A suitable substance  12  is a liquid that locally softens the exterior face of the tread elements  28 . To that end, it is appreciated that sodium hypochlorite or stabilized hydrogen peroxide of varying dilutions may be used. Other suitable active oxidizing materials include benzoyl peroxide, dicumyl peroxide, or any oxide that has an activation temperature within the anticipated operating temperature range. Solvents suitable for use present a vapor pressure high enough to remain in liquid form long enough to soften the tread  28 , and include toluene, ethyl benzene, and paramethyl toluene. Alternatively, a “sticky” substance  12  that binds or adheres to the tread material (e.g., rubber) and/or asphalt/concrete may be used. Lastly, it is appreciated that the substance  12  must be environmentally safe. 
         [0021]    In a second embodiment, the microcapsules  40  carry differing agents (or reactants)  12   a,b  that when inter-mixed react to form the performance enhancing substance  12 . In  FIG. 4   c , two different agents (e.g., an adhesive resin and an adhesive hardener, a solid and a solvent, etc.) are shown; however, it is certainly within the ambit of the invention to utilize a greater plurality of agents. Moreover, in certain conditions, such as winter weather conditions, it may be desirable to produce a solute, such as salt (not shown), that further separates from the substance  12 . Finally, it is appreciated that biological oxidizers, such as Managanese peroxidase and laccase, may also be utilized. 
         [0022]    In one example, the agents  12   a,b  are released at a higher rate of speed or under extreme conditions that result in higher temperatures and shear stresses at the face of the tread wall  24 . That is to say, the tread elements  28  and microcapsules  40  may be cooperatively configured so that elevated temperatures and stresses, but not normal operating temperatures and stresses, cause the shells of the microcapsules  40  to rupture. 
         [0023]    It is appreciated that tire treads  28  made with such formulations would be particularly useful on vehicles  14 , which do not have anti-lock braking systems, as these vehicles typically experience greater shear stresses when undergoing locking conditions. Finally, it is also appreciated that the release of the substance  12  may be caused or facilitated by thermal heat energy; and to that end, the tire  10  may further include on-demand heating elements  42  operable to selectively heat the treadwall  24 . For example, and as shown in  FIGS. 1 and 3 , a plurality of resistively heated wires may be circumferentially inserted within the treadwall  24  and electrically coupled to a power source  44 . 
         [0024]    In a second aspect of the invention, an alternative method of releasing the performance enhancing substance  12  directly onto the tire  10 , or upon the surface  16  immediately fore the contact patch defined by the tire  10  and roadway surface  16  is presented. As shown in  FIG. 1 , the substance  12  may be stored in a reservoir  46  composing the vehicle  12 . For example, a reservoir  46  may be positioned just fore the tires  10  and fluidly coupled to at least one orifice  48  preferably via a pump  50 . The pump  50  and orifice  48  are cooperatively configured to direct a jet of substance  12  either directly into the patch or upon the treadwall  24  approaching the patch. The reservoir may be positioned atop the tire  10  and configured to dispense substance  12  at a controlled rate due to gravity. Here, a door may be used to selectively enable release. The orifice  48  is preferably located and configured to direct a liquid substance  12  towards the rib  26  or lateral centerline of the tire  10 , as it is appreciated that the tread elements  28  are typically configured to disperse liquids laterally. 
         [0025]    In operation, when the vehicle  12  achieves a predetermined condition, the tire  10  is configured to autonomously effect release, or an actuation signal is delivered to the resistive elements  42 , pump  50 , or door to cause or enable release. A preferred condition is the exceedance of a predetermined speed (e.g., 50 mph), a minimum shear stress defined by the face and surface  16 , or the beginning of slippage between the face and surface  16 . As such, the vehicle  12  preferably includes at least one sensor (e.g., speedometer, wheel speed sensor, etc.)  52  operable to detect the condition, and a controller  54  communicatively coupled to the sensor  52  and tire  10  and operable to effect release only when the condition is detected. More preferably, the degree of release is proportional to the condition (e.g., speed of the vehicle), such that a greater amount of substance  12  is released at higher speeds, etc. For example, the heating element  42  may be caused to produce a greater amount of heat more rapidly as the speed increases. When the vehicle condition completely stops (e.g., the speed is reduced past a minimum threshold), the passive releasing force, or signal from the controller  54  is ceased. The process may be repeated until the quantity of stored substance  12  is depleted. 
         [0026]    As used herein, the terms “first”, “second”, and the like do not denote any order or importance, but rather are used to distinguish one element from another, and the terms “the”, “a”, and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Furthermore, all ranges directed to the same quantity of a given component or measurement is inclusive of the endpoints and independently combinable. 
         [0027]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.