Collapsible tire, method for collapsing same, and use thereof
View Patent ↗The collapsible tire includes at least one carcass reinforcement that is surmounted radially from the outside by an inextensible crown reinforcement, which is radially on an inside of a tread. The reinforcements each include at least one layer of reinforcing elements. The tread is connected to two beads by two sidewalls. The beads are intended to come into contact with a rim, and each bead has at least one circumferential reinforcing element called a bead wire. The bead wire defines a mean line which forms a substantially circular closed curve in a circumferential plane. The bead wires are flexible and have at least one concave part P c with a radius R c and a center of curvature C c .
1. A collapsed tire for a vehicle, comprising:
a carcass that has a width which is at least 175 mm,
at least one carcass reinforcement associated with an inextensible crown reinforcement,
the at least one carcass reinforcement being disposed radially on the inside of a tread,
the reinforcements each comprising at least one layer of reinforcing elements,
the tread being connected to two beads by two sidewalls,
the beads being intended to come into contact with a rim,
each bead comprising at least one inextensible circumferential reinforcing element called a bead wire,
the sidewalls having a thickness between 2.6 and 7 mm and the crown reinforcement having a thickness between 2 and 7 mm,
wherein the bead wire of each bead is flexible, and
a mean line of each bead wire extending through a non-overlapping, closed-loop and non-circular shape in a circumferential plane, and said non-overlapping, closed-loop and non-circular shape defining at least one concave part (P c ) with a radius (R c ) with a center of curvature (C c ).
2. The tire according to claim 1 , wherein the mean line of each bead wire further defines at least two points of inflexion (I 1 , I 2 ) delimiting the at least one concave part (P c ).
3. The tire according to claim 1 , wherein the closed-loop, non-circular shape of each mean line of each bead wire approximates an S-shape which has two convex parts (P x1 , P x2 ) having two radii (R x1 , R x2 ) and having two centers of curvature (C x1 , C x2 ), and wherein straight lines (D 1 , D 2 ) respectively connect the center of curvature (C c1 ) of the concave part (P c ) to each of the centers of curvature (C x1 , C x2 ) of the convex parts (P x1 , P x2 ) and wherein the straight lines (D 1 , D 2 ) are angled relative to one another at an angle α that is between 30° and 125°.
4. The tire according to claim 1 , wherein the mean line of the bead wire of each bead is formed by winding a metal cord, formed of filaments, which is saturated and unwrapped, wherein the diameter of the cord is less than 1.5 mm and wherein the diameter of the filament is less than 0.25 mm.
5. The tire according to claim 1 , wherein the closed-loop, non-circular shape of each mean line of each bead wire approximates an S-shape which has two convex parts (P x1 , P x2 ), respectively with smaller radii (R x1 , R x2 ) than the radius (R c ) of the at least one concave part (P c ), and having centers of curvature (C x1 , C x2 ), and wherein straight lines (D 1 , D 2 ) respectively connect the center of curvature (C c1 ) of the concave part (P c ) to each of the centers of curvature (C x1 , C x2 ) of the convex parts (P x1 , P x2 ) and wherein the straight lines (D 1 , D 2 ) are angled relative to one another at an angle α that is between 40 and 140°.
6. A plurality of the collapsed tires set forth in claim 1 , wherein when stored, the tires occupy a volume that is less than 65% by comparison with a lacing mode of packaging tires.
7. A method for collapsing a tire with at least one carcass reinforcement associated with an inextensible crown reinforcement,
a carcass with a width that is at least 175 mm,
the at least one carcass reinforcement being disposed radially on the inside of a tread,
the reinforcements each comprising at least one layer of reinforcing elements,
the tread being connected by two beads by two sidewalls,
the beads being intended to come into contact with a rim,
each bead comprising at least one inextensible circumferential reinforcing element called a bead wire, and
the sidewalls having a thickness between 2.6 and 7 mm and the crown reinforcement having a thickness between 2 and 7 mm,
comprising the steps of:
parting, in a radial plane, the beads of a part of the tire along an axial direction towards an axis tangential to the center of the tread of the tire in the said radial plane,
applying a force in a radial direction to the said tread so as to move the tread closer to a cavity opposite the force to collapse the tire into the shape of a double-walled arc of a circle comprising a base that is connected with two axes such that a mean line of each bead wire extends through a non-overlapping, closed-loop and non-circular shape in a circumferential plane and defines at least one concave part (P c ) with a radius (R c ) and with a center of curvature (C c ).
8. A method for collapsing a tire with at least one carcass reinforcement associated with an inextensible crown reinforcement,
a carcass with a width that is at least 175 mm,
the at least one carcass reinforcement being disposed radially on the inside of a tread,
the reinforcements each comprising at least one layer of reinforcing elements,
the tread being connected by two beads by two sidewalls,
the beads being intended to come into contact with a rim,
each bead comprising at least one inextensible circumferential reinforcing element called a bead wire, and
the sidewalls having a thickness between 2.6 and 7 mm and the crown reinforcement having a thickness between 2 and 7 mm,
comprising the steps of:
parting, in a radial plane, the beads of a first part of the tire along an axial direction towards an axis tangential to the center of the tread,
applying a first force (F 1 ) in a first circumferential direction to the said tread so as to move a corresponding cavity closer to another part of the cavity of the tire,
parting, in a radial plane, the beads of a second part of the tire in an axial direction towards an axis tangential to the center of the tread,
applying a compression force in the radial direction to the said first and/or second part, and a second force (F 2 ) in a second circumferential direction, of opposite sense to the said first force (F 1 ) to the said tread so as to move the corresponding cavity closer to another part of the cavity of the tire such that a mean line of each bead wire extends through a non-overlapping, closed-loop and non-circular shape in a circumferential plane and defines at least one concave part (P c ) with a radius (R c ) and with a center of curvature (C c ), and
continuing to apply the compression force until the non-overlapping, closed-loop and non-circular shape of the mean line of each bead wire when the tire is collapsed is a double-walled arc shape or an S-shape.