Piezoelectric triggering mechanism

• US 8,193,926 B2
• Filed: 03/14/2006
• Issued: 06/05/2012
• Est. Priority Date: 03/14/2006
• Status: Active Grant

• Current Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Original Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Sinnett, Jay C., Adamson, John D., O'Brien, George P.
• Primary Examiner(s): Swarthout, Brent
• Application Number:
  US12/278,623
• Publication Number:
  US 20090315694A1
• Time in Patent Office: 2,275 Days
• Field of Search: 340/442, 340/445, 340/447, 340/443, 731/465, 737/02, 737/63, 737/68, 152/520, 152/381.5, 377/24.1
• US Class Current: 340/443
• CPC Class Codes: B60C 23/0411 Piezoelectric generators
• CPC Class Codes: B60C 23/0493 for attachment on the tyre

Abstract

A piezoelectric triggering mechanism (10) includes a piezoelectric element (12), such as the transducer of a SAW device, that is configured to crack or break upon being subjected to excessive levels of mechanical force or other triggering mechanisms, thus generating a burst of electromagnetic energy. The large impulse of energy can then be conditioned (14) through resonant circuits or antennas and modulated (16) with an identification pattern through appropriate structures (such as SAW electrodes) to send a breakage indication signal to a remote receiver (18). Piezoelectric elements (12) may be integrated with a pneumatic tire structure to provide indication upon pressure loss or tire failure. Piezoelectric elements (12) may also be integrated with safety support features of some tire structures to provide indication of tire operation in a run-flat mode of operation. Related aspects of the present piezoelectric triggering technology employ a piezoelectric element (12) in a trigger detection method, which may involve detection of such occurrences as breach of security via opening of a sealed access structure or breakage of a glass panel, deployment of an airbag, loss of pressure or excess deflection in a tire, presence of smoke in a given location, and other rupture and sensor applications.

Claims

1. A piezoelectric triggering mechanism, comprising:

a pneumatic tire structure characterized by a crown having a tread portion for making contact with a ground surface; and

a piezoelectric element configured to crack or break upon being subjected to a sufficient amount of mechanical force, said piezoelectric element generating a burst of electromagnetic energy upon cracking or breaking; and

a modulation circuit coupled to said piezoelectric element and configured to receive electromagnetic energy from said piezoelectric element and to radiate a triggering signal therefrom when the energy level output by the piezoelectric element exceeds normal levels characteristic of mere deformation of the piezoelectric element

wherein said piezoelectric element is integrated at a select location relative to said pneumatic tire structure such that excess deflection of said pneumatic tire structure results in the cracking or breaking of said piezoelectric element.

2. A piezoelectric triggering mechanism as in claim 1, further comprising a conditioning circuit linking said piezoelectric element to said modulation circuit, said conditioning circuit configured to condition an energy signal corresponding to said burst of electromagnetic energy.

3. A piezoelectric triggering mechanism as in claim 1, wherein said piezoelectric element comprises a surface acoustic wave (SAW) transducer.

4. A piezoelectric triggering mechanism as in claim 3, wherein said modulation circuit comprises electrodes of said SAW transducer.

5. A piezoelectric triggering mechanism as in claim 2, wherein said conditioning circuit comprises an energy storage element configured to store energy generated by said piezoelectric element for subsequent identification that the piezoelectric element was cracked or broken.

6. A piezoelectric triggering mechanism as in claim 1, wherein said modulation circuit comprises one of a resonant circuit or an antenna.

7. A piezoelectric triggering mechanism as in claim 2, wherein said conditioning circuit comprises a comparator element for comparing the output of said piezoelectric element with a predetermined threshold level.

8. A piezoelectric triggering mechanism as in claim 1, further comprising a substrate on which said piezoelectric element is provided.

9. A piezoelectric triggering mechanism as in claim 8, wherein said substrate includes an adhesive backing.

10. A piezoelectric triggering mechanism as in claim 1, wherein the occurrence of excess deflection of said pneumatic tire structure is caused by one of under-inflation, loss of pressure and severe impact.

11. A piezoelectric triggering mechanism as in claim 8, further comprising a safety support configured for mounting on a wheel rim inside of said pneumatic tire structure in order to support the tread portion of said pneumatic tire structure in the event of loss of inflation.

12. A piezoelectric triggering mechanism as in claim 11, wherein said piezoelectric element is integrated at a select location relative to said safety support.

13. A piezoelectric triggering mechanism as in claim 11, wherein said safety support comprises an annular body having an inner surface intended to fit around the wheel rim and an outer cap intended to be engaged by the tread portion in the event of a loss of pressure.

18. A piezoelectric triggering mechanism as in claim 1, wherein said piezoelectric element is provided at an interior side wall surface of said pneumatic tire structure.

14. A method of detecting a triggered event, comprising the steps of:

providing a piezoelectric element configured to crack or break upon being subjected to a sufficient amount of mechanical force, said piezoelectric element configured to generate a burst of electromagnetic breaking;

providing a modulation element coupled to said piezoelectric element and configured to receive the burst of electromagnetic energy and to radiate a breakage indication signal therefrom when the energy level output by the piezoelectric element exceeds normal levels characteristic of mere deformation of the piezoelectric element;

providing a remote receiver for detecting transmission of the breakage indication signal when the piezoelectric element cracks or breaks; and

locating the piezoelectric element at a select location relative to a pneumatic tire structure such that excess deflection of the pneumatic tire structure results in the cracking or breaking of said piezoelectric element.

15. A method as in claim 14, further comprising a step of relaying an alert when the remote receiver receives the breakage indication signal from the piezoelectric and modulation elements.

16. A method as in claim 14, further comprising the steps of:

providing the piezoelectric and modulation elements on a substrate; and

adhering the substrate to a given surface.

17. A method as in claim 14, further comprising a step of manipulating the triggering signal such that the signal radiated from the modulation element includes an identification pattern.