Patent Application
20110000733
1. Field of the Invention
The present disclosure generally relates to tires, such as automobile tires, and more particularly to methods of enhancing tire performance using releasable elements.
2. Discussion of Prior Art
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.
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.
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.
The above described and other features are exemplified by the following figures and detailed description.
Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures of exemplary scale, wherein:
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;
b is an elevation of the tire shown in
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.
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 (
As best shown in
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
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.
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.
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.
In a second embodiment, the microcapsules 40 carry differing agents (or reactants) 12a,b that when inter-mixed react to form the performance enhancing substance 12. In
In one example, the agents 12a,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.
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
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
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.
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.
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.
