Measuring and testing – Tire – tread or roadway – Tire inflation testing installation
Reexamination Certificate
2003-01-15
2004-04-27
Oen, William (Department: 2855)
Measuring and testing
Tire, tread or roadway
Tire inflation testing installation
C073S146000
Reexamination Certificate
active
06725713
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally concerns a system and method for subjecting piezoelectric structures to the mechanical energy of conventional tire rotation, thereby generating electric power for integrated tire electronics. Piezoelectric technology is utilized to convert mechanical strain associated with tire flexure to electric charge that is then conditioned and stored in an energy storage device. Sufficient accumulations of such stored energy can then power electronic systems including components for identifying various physical tire parameters as well as radio frequency (RF) transmission devices.
BACKGROUND OF THE INVENTION
The incorporation of electronic devices with pneumatic tire structures yields many practical advantages. Tire electronics may include sensors and other components for obtaining information regarding various physical parameters of a tire, such as temperature, pressure, number of tire revolutions, vehicle speed, etc. Such performance information may become useful in tire monitoring and warning systems, and may even potentially be employed with feedback systems to regulate proper tire pressure levels.
U.S. Pat. No. 5,749,984 (Frey et al.) discloses a tire monitoring system and method that is capable of determining such information as tire deflection, tire speed, and number of tire revolutions. Another example of a tire electronics system can be found in U.S. Pat. No. 4,510,484 (Snyder), which concerns an abnormal tire condition warning system. U.S. Pat. No. 4,862,486 (Wing et al.) also relates to tire electronics, and more particularly discloses an exemplary revolution counter for use in conjunction with automotive and truck tires.
Yet another potential capability offered by electronics systems integrated with tire structures corresponds to asset tracking and performance characterization for commercial vehicular applications. Commercial truck fleets, aviation crafts and earthmover/mining vehicles are all viable industries that could utilize the benefits of tire electronic systems and related information transmission. Tire sensors can determine the distance each tire in a vehicle has traveled and thus aid in maintenance planning for such commercial systems. Vehicle location and performance can be optimized for more expensive applications such as those concerning earth mining equipment. Entire fleets of vehicles could be tracked using RF tag transmission, exemplary aspects of which are disclosed in U.S. Pat. No. 5,457,447 (Ghaem et al.).
Such integrated tire electronics systems have conventionally been powered by a variety of techniques and different power generation systems. Examples of mechanical features for generating energy from tire movement are disclosed in U.S. Pat. No. 4,061,200 (Thompson) and U.S. Pat. No. 3,760,351 (Thomas). Such examples provide bulky complex systems that are generally not preferred for incorporation with modern tire applications. Yet another option for powering tire electronics systems is disclosed in U.S. Pat. No. 4,510,484 (Snyder), which concerns a piezoelectric reed power supply symmetrically configured about a radiating center line of a tire.
Another typical solution for powering tire electronics systems corresponds to the use of a non-rechargeable battery, which inherently provides an inconvenience to the tire user since proper electronics system operation is dependent on periodic battery replacement. Conventional batteries also often contain heavy metals that are not environmentally friendly and which present disposal concerns, especially when employed in highly numerous quantities. Still further, batteries tend to deplete their energy storage quite rapidly when powering electronic applications characterized by complex levels of functionality. Battery storage depletion is especially prevalent in electronic systems that transmit information over a relatively far distance such as from truck wheel locations to a receiver in the truck cabin. Even when batteries are used in electronics systems that transmit from wheel locations to a closer receiver location, information is then typically relayed via hard-wire transmission medium from the RF receiver location to the vehicle cab thus requiring the installation of additional and often expensive communications hardware in a vehicle.
Yet another known method for deriving power for tire monitoring systems relates to scavenging RF beam power with an interrogation antenna in close proximity to a tire and integrated electronic features. Energy that is radiated from the antenna is scavenged to power the electronics, which must often be very specialized ultra-low-power electronics limited to within a few microwatts. Interrogation antennas employed in conjunction with beam-powered electronics must typically be placed in relatively close proximity (within about two feet) to each wheel well due to limited transmission ranges. This typically requires multiple interrogation antennas per vehicle, thus adding to potential equipment costs. Each antenna is also quite susceptible to damage from road hazards, and thus for many reasons may not be the most desirable solution for powering certain tire electronic applications.
In accordance with the present subject matter, it is appreciated that certain advantages of piezoelectric materials have long been recognized. However, such technology is constantly improving, thus potentially affording applications that utilize piezoelectric materials with improved operating capabilities. Examples of relatively new advances in piezoelectric technology are provided in U.S. Pat. No. 5,869,189 (Hagood, IV et al.) and U.S. Pat. No. 6,048,622 (Hagood, IV et al.), directed to composites for structural control. The presently disclosed technology concerns further advances in piezoelectric technology such that a piezoelectric power generating device can be integrated with a tire or wheel assembly for purposes of energy harvesting. Given that piezoelectric materials are often highly susceptible to excessive strain levels, additional aspects of the present invention help ensure that such integrated piezoelectric materials are reinforced to decrease strain levels and the risk of material damage.
The disclosures of all of the foregoing United States patents are hereby fully incorporated into this application for all purposes by reference thereto. While various tire electronics systems and power generation systems therefor have been developed, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.
BRIEF SUMMARY OF THE INVENTION
In view of the recognized features encountered in the prior art and addressed by the present subject matter, an improved system and method for powering electronic systems integrated within a tire structure has been developed. Piezoelectric technology is utilized to convert mechanical strains associated with tire flexure to electric charge that is then conditioned and stored in an energy storage device. Sufficient accumulations of such stored energy can then power various electronics components within a tire, including a radio frequency (RF) device to wirelessly relay information from within a tire.
In accordance with more particular aspects of the disclosed technology, it is an object of the present subject matter to provide a pneumatic tire with integrated self-powered electronic components. Such electronic components receive power from integrated piezoelectric structures and may correspond to such components as a rechargeable battery, a revolution counter, an active RFID transponder, etc. A still further electronic application concerns an electronics assembly designed to measure and transmit information regarding tire conditions such as pressure and temperature, as well as other information such as the number of tire revolutions or general tire identification variables. Variety is also afforded to the type of piezoelectric material employed in the subject integrated piezoelectric structures. Exemplary piezoelectric materials include
Adamson John David
O'Brien George Phillips
Dority & Manning P.A.
Michelin & Recherche et Technique S.A.
Oen William
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