Self-healing and self-cleaning tires utilizing active material actuation
A self-healing and/or self-cleaning tire comprising at least one active material element configured when undergoing an actuation cycle to repair a structural anomaly, such as a crack or puncture, and/or remove a surface anomaly, such as foreign substances or objects adhered to or lodged in the tire.
1. A tire, comprising a tire body bounded by an exterior viewable surface and hidden interior face, the tire being adapted to autonomously repair or remove an anomaly located on the exterior viewable tire surface or an anomaly which extends inwardly from the exterior viewable surface, at least a portion of one of the exterior viewable surface and interior face comprising a shape memory polymer active material element applied as a coating layer, the shape memory polymer active material element undergoing a reversible change from a lower temperature polymer phase to a lower modulus, higher temperature polymer phase, when heated to a temperature greater than an intended tire operating temperature, and,
the shape memory polymer coating layer is positioned an arranged to geometrically modify the exterior viewable surface of the tire to repair or remove the anomaly when a low temperature to higher temperature polymer phase change of the shape memory polymer is performed and then reversed.
2. The tire as claimed in claim 1 , wherein the tire comprises first and second sidewalls and a tread wall with tread elements and grooves between the tread elements, the layer of shape memory polymer active material element presents a homogenous coating superjacent at least a portion of the sidewalls and/or grooves of the tread wall, and the shape memory polymer active material element coating, or said at least portion, forms the exterior viewable surface.
3. The tire as claimed in claim 2 , wherein the sidewalls and tread wall define inner and outer surfaces, and the coating of shape memory polymer active material is positioned adjacent the outer surface and defines the exterior viewable surface.
4. The tire as claimed in claim 2 , wherein the sidewalls and tread wall define inner and outer surfaces, and the coating of shape memory polymer active material is positioned on the inner surface, of at least a portion of the sidewalls and/or tread wall.
5. The tire as claimed in claim 1 , further comprising a shape memory alloy active material element inter-engaged with the shape memory polymer active material element coating layer, and configured to conform the shape memory polymer active material element coating layer, so as to further enable the lower temperature to higher temperature phase change of the shape memory polymer active material element coating layer to repair or remove to anomaly.
6. The tire as claimed in claim 5 , wherein the shape memory alloy active material element is one of the group consisting of wires, strips, sheets, meshes, weaves, and discrete segments thereof.
7. The tire as claimed in claim 6 , wherein the shape memory alloy active material element is formed of Martensitic shape memory alloy and is pre-stretched.
8. The tire as claimed in claim 6 , wherein the shape memory alloy active material element is formed of Austenitic shape memory alloy.
9. The tire as claimed in claim 5 in which the shape memory alloy active material element undergoes transformation from a low temperature phase to a higher temperature phase at a lower temperature than the transformation of the shape memory polymer active material element and the shape alloy active material element undergoes a reverse transformation from its high temperature phase to its low temperature phase at a temperature which is lower than the temperature at which the shape memory polymer active material element transforms from its high temperature phase to its low temperature phase.
10. The tire as claimed in claim 1 , wherein the anomaly is a structural anomaly and selected from the group consisting of cracks, fractures, scratches, peels, and punctures.
11. A tire as recited in claim 1 in which the shape memory polymer, when in its higher temperature phase, exhibits a shape memory effect to bring separated tire surfaces back into contact and promote self-healing/rejoining of the previously-separated surfaces through the migration of long chain molecules leading to cohesive bonding.
12. A tire comprising a tire body bounded by an exterior viewable surface and hidden interior face, the tire being adapted to autonomously repair or remove an anomaly located on the exterior viewable surface, at least a portion of one of the exterior viewable surface and interior face comprising a shape memory polymer active material element applied as a coating layer, the shape memory polymer active material element coating layer undergoing a reversible change from a lower temperature polymer phase to a lower modulus higher temperature polymer phase when heated to a temperature greater than an intended tire operating temperature,
the shape memory polymer active material coating layer being configured to geometrically modify the exterior viewable surface so as to repair or remove the anomaly when a low temperature to higher temperature polymer phase change of the shape memory polymer is activated and then reversed; and, the tire further comprising
shape memory alloy active material wire elements dispersed in the shape memory polymer active material element coating layer, and operable to conform the shape memory polymer active material element coating layer, so as to further enable the reversible change of the shape memory polymer active material element coating layer to repair or remove the anomaly.
13. A tire as recited in claim 12 in which the shape memory alloy wire elements are in the martensite phase at temperatures up to the intended tire operating temperature and are operable to undergo a reversible change to an austenite phase when heated above the intended tire operating temperature, the reversible change in the shape memory wire elements being configured to further enable the reversible change of the shape memory polymer active material to repair or remove the anomaly.
14. A tire as recited in claim 12 in which the shape memory alloy wire elements are in the austenite phase at temperatures up to the intended tire operating temperature and display superelasticity to further enable the reversible change of the shape memory polymer active material to repair or remove the anomaly.
15. A tire as recited in claim 12 in which the shape memory polymer, when in its higher temperature phase, exhibits a shape memory effect to bring separated tire surfaces back into contact and promote self-healing/rejoining of the previously-separated surfaces through the migration of long chain molecules leading to cohesive bonding.