PIEZOELECTRIC MODULE FOR ENERGY HARVESTING, SUCH AS IN A TIRE PRESSURE MONITORING SYSTEM

• US 20090211353A1
• Filed: 02/22/2008
• Published: 08/27/2009
• Est. Priority Date: 02/22/2008
• Status: Active Grant

• Current Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Original Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Inventors: Sham, Man-Lung, Chung, Chang Hwa, Gao, Ziyang
• Granted Patent: US 8,011,237 B2
• Time in Patent Office: Days
• US Class Current: 73/146.500
• CPC Class Codes: B60C 23/0411 Piezoelectric generators
• CPC Class Codes: H02N 2/18 producing electrical output from mechanical input, e.g. generators for measurement devices G01
• CPC Class Codes: H10N 30/304 Beam type
• CPC Class Codes: H10N 30/306 Cantilevers

Abstract

Subject matter disclosed herein may relate to energy harvesting piezoelectric modules as may be used, for example, in power supplies for tire pressure monitoring systems.

Claims

1. An apparatus, comprising:

a body;

a beam comprising a first end and a second end, the first end fixed to the body, the beam further comprising a first side facing the body, the beam to flex in response to accelerations imparted to the body; and

a first piezoelectric element fixed to the first side of the beam, the piezoelectric element to generate a first voltage in response to flexion of the beam and further to generate a second voltage in response to compression of the first piezoelectric element against the body.

2. The apparatus of claim 1, wherein the body comprises an upper inner surface, a lower inner surface, and a first inner end surface, wherein the beam is fixed to the first inner end surface and wherein the first side of the beam faces the upper inner surface.

3. The apparatus of claim 2, wherein the beam comprises a second side facing the bottom inner surface of the body, and further comprising a second piezoelectric element fixed to the second side of the beam, the second piezoelectric element to generate a third voltage in response to flexion of the beam and further to generate a fourth voltage in response to compression of the second piezoelectric element against the body.

4. The apparatus of claim 3, wherein the body further comprises:

a first constraint member fixed to the upper inner surface, wherein the first constraint member is positioned between the first piezoelectric member and the upper inner surface; and

a second constraint member fixed to the lower inner surface, wherein the second constraint member is positioned between the second piezoelectric member and the lower inner surface.

5. The apparatus of claim 3, wherein the first and second piezoelectric elements are comprised of bulk piezoelectric materials.

6. The apparatus of claim 5, wherein the first and second piezoelectric elements are comprised of ceramic piezoelectric materials.

7. The apparatus of claim 6, further comprising an energy storage circuit coupled to the first and second piezoelectric elements, the energy storage unit to receive the first and second voltages generated by the first piezoelectric element and the third and fourth voltages generated by the second piezoelectric element.

8. The apparatus of claim 7, further comprising a tire pressure sensor circuit coupled to the energy storage circuit, wherein the apparatus is adapted to be mounted on an automobile wheel inside a tire, the beam to flex in response to accelerations imparted by the wheel.

9. The apparatus of claim 8, further comprising a mass at the second end of the beam.

10. The apparatus of claim 9, wherein the beam is comprised of metal.

11. The apparatus of claim 10, wherein the body is comprised of metal.

12. The apparatus of claim 10, wherein the body is comprised of plastic.

13. A system, comprising:

a sensor;

a radio transmitter coupled to the sensor, the radio transmitter to transmit information generated by the sensor;

an energy storage circuit coupled to the sensor and to the radio transmitter; and

a piezoelectric module coupled to the energy storage circuit, the piezoelectric module comprising

a body,

a beam comprising a first end and a second end, the first end fixed to the body, the beam further comprising a first side facing the body, the beam to flex in response to accelerations imparted to the body, and

a first piezoelectric element fixed to the first side of the beam, the first piezoelectric element to generate a first voltage in response to flexion of the beam and further to generate a second voltage in response to compression of the first piezoelectric element against the body.

14. The system of claim 13, wherein the sensor comprises a tire pressure sensor, the radio transmitter to transmit tire pressure information generated by the tire pressure sensor.

15. The system of claim 13, wherein the body comprises an upper inner surface, a lower inner surface, and a first inner end surface, wherein the beam is fixed to the first inner end surface and wherein the first side of the beam faces the upper inner surface.

16. The system of claim 15, wherein the beam comprises a second side facing the bottom inner surface of the body, and further comprising a second piezoelectric element fixed to the second side of the beam, the second piezoelectric element to generate a third voltage in response to flexion of the beam and further to generate a fourth voltage in response to compression of the second piezoelectric element against the body.

17. The system of claim 16, wherein the body further comprises:

a first constraint member fixed to the upper inner surface, wherein the first constraint member is positioned between the first piezoelectric member and the upper inner surface; and

a second constraint member fixed to the lower inner surface, wherein the second constraint member is positioned between the second piezoelectric member and the lower inner surface.

18. The system of claim 16, wherein the first and second piezoelectric elements are comprised of bulk piezoelectric materials.

19. The system of claim 18, wherein the first and second piezoelectric elements are comprised of ceramic piezoelectric materials.

20. The system of claim 19, further comprising a mass at the second end of the beam.

21. The system of claim 20, wherein the beam is comprised of metal.

22. The system of claim 21, wherein the body is comprised of metal, and wherein the first and second constraint members comprise an insulating material.

23. The system of claim 21, wherein the body is comprised of plastic.

24. A method, comprising:

flexing a piezoelectric element to generate a first voltage;

compressing the piezoelectric element to generate a second voltage; and

applying the first and second voltages to an energy storage circuit.

25. The method of claim 24, further comprising applying energy stored in the energy storage circuit to a sensor.

26. The method of claim 25, wherein said applying energy stored in the energy circuit to the sensor comprises applying energy stored in the energy circuit to a tire pressure sensor.

27. An apparatus, comprising:

means for flexing a piezoelectric element to generate a first voltage;

means for compressing the piezoelectric element to generate a second voltage; and

means for applying the first and second voltages to an energy storage circuit.

28. The apparatus of claim 27, further comprising means for applying energy stored in the energy storage circuit to a sensor.

29. The apparatus of claim 28, wherein said means for applying energy stored in the energy circuit to the sensor comprises means for applying energy stored in the energy circuit to a tire pressure sensor.

30. A wheel assembly, comprising:

a wheel; and

a tire pressure monitoring sensor fixed to the wheel and positioned such that if a tire is mounted on the wheel, the tire pressure monitoring sensor is exposed to an air pressure of the tire, wherein the tire pressure monitoring sensor comprises

a piezoelectric module comprising a piezoelectric element to generate a voltage if the piezoelectric element is flexed in response to an acceleration imparted by the wheel to the piezoelectric module and to generate an additional voltage if the piezoelectric element is compressed in response to the acceleration imparted by the wheel to the piezoelectric module.