METHODS OF REDUCING TIRE ROLLING RESISTANCE UTILIZING ACTIVE MATERIAL ACTUATION
An adaptive tire employable by a vehicle traveling upon a surface, so as to define a rolling resistance, and including at least one active material element operable to selectively modify the resistance when activated.
1 . A tire employable by a vehicle traveling upon a surface, so as to present a rolling resistance, and adapted to selectively modify the rolling resistance, said tire comprising:
at least one structural component presenting a first performance characteristic contributory to the resistance; and
at least one active material element inter-engaged with, and operable to modify the characteristic, so as to modify the resistance, when activated.
2 . The tire as claimed in claim 1 , wherein the component includes a treadwall, the treadwall defines an overall treadwall stiffness, and the element is configured to modify the stiffness.
3 . The tire as claimed in claim 2 , wherein the component presents a tread wall further comprising a plurality of tread elements defining a tread pattern, each tread element defines a tread element stiffness and depth, and the element is operable to modify the pattern, stiffness, and/or depth, when activated.
4 . The tire as claimed in claim 3 , wherein the tread elements define at least one sipe, groove, or opening, and the element is operable to close the sipe, groove, or opening.
5 . The tire as claimed in claim 1 , wherein the component includes first and second opposite sidewalls interconnected by a circumferential treadwall, and presenting a bead, and the element is formed of shape memory material and presents a hoop segment extending from bead to bead.
6 . The tire as claimed in claim 5 , wherein the segment extends at an angle.
7 . The tire as claimed in claim 1 , wherein the component includes a sidewall, and the element is formed of shape memory material and presents a hoop disposed within the sidewall.
8 . The tire as claimed in claim 7 , wherein the sidewall defines a radially outer periphery, and the hoop is disposed at or near the periphery.
9 . The tire as claimed in claim 1 , wherein the component includes a circumferential treadwall, and a reinforcing belt within the treadwall, and the element is formed of shape memory alloy and composes the belt.
10 . The tire as claimed in claim 1 , wherein the component includes a sidewall, the characteristic is the stiffness of the sidewall, and the element is configured to modify the stiffness.
11 . The tire as claimed in claim 1 , wherein the component includes a sidewall, the characteristic is the temperature of the sidewall, and the element is configured to modify the temperature.
12 . The tire as claimed in claim 1 , wherein the tire defines a longitudinal axis, said at least one component includes first and second sidewalls interconnected by a treadwall, and the element is made of shape memory material and presents a hoop oriented angularly relative to the axis, so as to be disposed within the sidewalls and treadwall.
13 . 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, and magnetostrictives.
14 . The tire as claimed in claim 1 , wherein the active material element is formed of a shape memory alloy and presents a geometric shape selected from the group consisting essentially of wires, strips, sheets, meshes, weaves, braids, cables, hoops, and discrete segments thereof.
15 . The tire as claimed in claim 1 , wherein the element presents a polygonal or “T”-shaped cross-section.
16 . The tire as claimed in claim 1 , wherein the component defines a surface irregularity, the characteristic is the heat loss due to convection associated with the irregularity when the tire rolls, and the element is configured to reduce the irregularity, so as to reduce the loss when activated.
17 . The tire as claimed in claim 1 , further comprising:
a signal source operable to produce an activation signal sufficient to activate the element;
a sensor operable to detect a condition; and
a controller communicatively coupled to the source, element, and sensor, and configured to cause the element to become activated when the condition is detected.
18 . A tire employable by a vehicle traveling upon a surface, so as to present a rolling resistance, and adapted to autonomously and selectively modify the rolling resistance, said tire comprising:
first and second sidewalls presenting a sidewall stiffness and temperature;
a treadwall interconnecting the sidewalls and presenting a treadwall stiffness and temperature;
at least one active material element inter-engaged with the sidewalls and/or treadwall, presenting a hoop, hoop segment, wire, and operable to modify the sidewall stiffness, sidewall temperature, treadwall stiffness, and/or treadwall temperature, so as to modify the resistance, when activated;
a signal source operable to produce an activation signal sufficient to activate the element;
a sensor operable to detect a condition; and
a controller communicatively coupled to the source, element, and sensor, and configured to cause the element to become activated when the condition is detected.
19 . A method of making an elastomeric tire comprising first and second sidewalls interconnected by a tread wall, and having a wire comprising shape memory alloy, said method comprising:
a. adding the SMA wire within a mold;
b. folding elastomeric sidewall and tread material around the wire to build the remainder of the tire;
c. curing the elastomer over an elastomer curing cycle, and maintaining the shape of the wire during the elastomer curing cycle; and
d. cooling the material in the mold to enhance the retention of the wire shape.
20 . The method as claimed in claim 19 , wherein step a) further includes the steps of pre-coating the wire with copper.