MAINTENANCE OF PROPER TIRE INFLATION PRESSURE THRU ACTIVE MATERIAL ACTUATION

• US 20090315696A1
• Filed: 06/22/2009
• Published: 12/24/2009
• Est. Priority Date: 06/24/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: RODGERS, WILLIAM R., COX, HOWARD WILLIAM, BROWNE, ALAN L., JOHNSON, NANCY L.
• Granted Patent: US 8,344,868 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• CPC Class Codes: B29D 30/0061 Accessories, details or auxiliary operations not otherwise provided for
• CPC Class Codes: B29D 30/52 Unvulcanised treads, e.g. on used tyres; Retreading apparatus for forming treads by extrusion B29C48/00; apparatus for vulcanising treads B29C35/02; apparatus characterised by the means for holding wheels or parts thereof B60B30/00
• CPC Class Codes: B60C 11/00 Tyre tread bands; Tread patterns; Anti-skid inserts
• CPC Class Codes: B60C 19/12 Puncture preventing arrangements
• CPC Class Codes: B60C 2019/004 Tyre sensors other than for detecting tyre pressure
• CPC Class Codes: B60C 9/18 Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
• CPC Class Codes: Y02T 10/86 Optimisation of rolling resistance, e.g. weight reduction
• CPC Class Codes: Y10T 152/10 Tires, resilient
• CPC Class Codes: Y10T 152/10675 Using flowable coating or composition

Abstract

An adaptive tire utilizing active material actuation to sense and/or modify an excessive and/or low inflation pressure, so as to autonomously maintain proper inflation pressure.

Claims

1. A tire presenting and adapted to selectively modify an inflation pressure, said tire comprising:

a structural component at least partially defining a confined space, wherein a quantity of air is retained to produce an inflation pressure upon the component; and

at least one active material element operable to undergo a reversible change in a fundamental property when exposed to or occluded from an activation signal,

said change being operable to sense the pressure, and/or modify the pressure by increasing or reducing the quantity.

2. The tire as claimed in claim 1, further comprising an energy harvesting mechanism engaged with the component, communicatively coupled to the element, and operable to extract energy from a deformation of the component and selectively expend the extracted energy, so as to activate the element.

3. The tire as claimed in claim 2, wherein the mechanism includes a capacitor operable to store the energy.

4. The tire as claimed in claim 2, wherein the mechanism includes a piezoelectric composite disposed along the component so as to be caused to deform when the tire rolls.

5. The tire as claimed in claim 1, wherein the element is formed of an active material selected from the group consisting essentially of shape memory alloys, electroactive polymers, piezoelectrics, magnetostrictives, and magnetorheological elastomers.

6. The tire as claimed in claim 5, wherein the active material element is formed of Martensitic shape memory alloy and is pre-stretched.

7. The tire as claimed in claim 1, further comprising:

a pump fluidly coupled to the space,

said element being drivenly coupled to the pump,

said pump and element being cooperatively configured to increase the quantity, as a result of the change.

8. The tire as claimed in claim 7, wherein said at least one element includes a piezoelectric element.

9. The tire as claimed in claim 8, wherein the piezoelectric element and pump are cooperatively configured to increase the quantity so as to define an inflated-to pressure, and the piezoelectric element presents a stiffness operable to limit the inflated-to pressure.

10. The tire as claimed in claim 7, further comprising:

a pressure sensor communicatively coupled to the space and operable to detect a low pressure less than a predetermined threshold,

said sensor, pump and element being cooperatively configured to increase the quantity, when the low pressure is detected.

11. The tire as claimed in claim 1, further comprising:

a release valve fluidly coupled to the space,

said element being drivenly coupled to the valve,

said valve and element being cooperatively configured to decrease the quantity, as a result of the change.

12. The tire as claimed in claim 11, wherein said at least one element includes an Austenitic shape memory alloy element configured to be deformed by the pressure, when the pressure is greater than a predetermined threshold.

13. The tire as claimed in claim 11, wherein said at least one element includes a piezoelectric element configured to be deflected by the pressure, when the pressure is greater than a predetermined threshold.

14. An autonomous tire inflation system adapted for use with a vehicle, said system comprising:

a tire having a structural component at least partially defining a confined space, wherein a quantity of air is retained to produce a first inflation pressure upon the component;

at least one active material element drivenly coupled to the component, and operable to undergo a reversible change in a fundamental property when exposed to or occluded from an activation signal,

a signal source operable to produce the signal;

an input device operable to receive an input; and

a controller communicatively coupled to the source, element, and device, and configured to cause the change when the input is received,

said change being operable to modify the pressure by increasing or reducing the quantity.

15. The system as claimed in claim 14, wherein the device is a pressure sensor, and the input is an excessive or low pressure reading.

16. The system as claimed in claim 15, wherein the sensor is a piezoelectric element.

17. The system as claimed in claim 14, wherein the source is a charging system composing the vehicle.

18. A method of autonomously maintaining a proper inflation pressure within a tire, said method comprising:

a. determining an excessive or low pressure greater or less than the proper pressure respectively;

b. activating an active material element, when the excessive or low pressure is determined;

c. causing air to leave the tire, when an excessive pressure is determined, or enter the tire, when a low pressure is determined, as a result of activating the element;

d. determining the proper pressure; and

e. deactivating the element.

19. The method as claimed in claim 18, wherein step a) further includes the steps of determining the excessive or low pressure by activating a second active material element.

20. The method as claimed in claim 18, wherein the element is drivenly coupled to a pump or release valve, and step c) further includes the steps of actuating the pump or valve as a result of activating the element.