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US 2006/0289102 A1Published application
Vehicle tire
AssigneeMichelin Recherche et Technique S.A.
InventorsPascal Prost, Alain Valle
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AssigneeMichelin Recherche et Technique S.A.
InventorsPascal Prost, Alain Valle
Estimating the term…
The invention relates to a tire for a two-wheeled motorized vehicle and more particularly a motorcycle. Such a tire comprises a carcass-type reinforcement structure, formed of reinforcement elements and anchored on each side of the tire to a bead whose base is intended to be fitted on a rim seat, each bead being extended radially towards the outside by a sidewall, the sidewalls meeting up radially towards the outside with a tread, and comprising under the tread a crown reinforcement structure consisting of at least one layer of reinforcement elements known as a working layer. According to the invention, said crown reinforcement structure further comprises a layer of circumferential reinforcement elements radially to the outside of the carcass-type reinforcement structure and, over the profile of the tire in a radial plane, in its part radially to the outside of the two points of tangency of the curvilinear abscissa of the carcass-type reinforcement structure with perpendiculars to the axis of rotation at least one layer of working reinforcement elements is at least partially radially to the inside of the part of the carcass-type reinforcement structure radially to the outside of the two points of tangency of the curvilinear abscissa of the carcass-type reinforcement structure with perpendiculars to the axis of rotation.
1- A tire comprising a carcass-type reinforcement structure, formed of reinforcement elements and anchored on each side of the tire to a bead whose base is intended to be fitted on a rim seat, each bead being extended radially towards the outside by a sidewall, the sidewalls meeting up radially towards the outside with a tread, and comprising under the tread a crown reinforcement structure consisting of at least one layer of reinforcement elements known as a working layer, said crown reinforcement structure comprising at least one additional layer of circumferentially oriented reinforcement elements radially to the outside of the carcass-type reinforcement structure, wherein, over the profile of the tire in a radial plane, in its part radially to the outside of the two points of tangency of the curvilinear abscissa of the carcass-type reinforcement structure with perpendiculars to the axis of rotation at least one layer of working reinforcement elements is at least partially radially to the inside of the part of the carcass-type reinforcement structure radially to the outside of the two points of tangency of the curvilinear abscissa of the carcass-type reinforcement structure with perpendiculars to the axis of rotation.
2- A tire according to claim 1, wherein at least one layer of working reinforcement elements consists of at least one continuous reinforcement cord forming in the central zone of said layer portions having identical angles formed with the longitudinal direction, said angles being measured at the points of intersection with a circumferential plane, wherein two adjacent portions are linked by a loop, and wherein the portions form an angle with the longitudinal direction of between 10 and 80°.
3- A tire according to claim 2, wherein, in the central zone of said layer, the portions are equidistant from one another over all circumferential planes.
4- A tire according to claim 2, wherein the angles formed by said portions with the longitudinal direction are variable in the transverse direction and wherein said angles are greater at the axially outer edges of the layers of reinforcement elements relative to the angles of said portions measured at the level of the equatorial plane of the tire.
5- A tire according to claim 1, wherein at least one layer of working reinforcement elements consists of at least one continuous reinforcement cord forming portions in the central zone of said layer, wherein two adjacent portions are linked by a loop, wherein said portions form an angle with the longitudinal direction of between 10 and 80°, wherein the angles formed by said portions with the longitudinal direction are variable in the transverse direction and wherein said angles are greater at the axially outer edges of the layers of reinforcement elements relative to the angles of said portions measured at the level of the equatorial plane of the tire.
6- A tire according to claim 4 or 5, wherein the angles of the portions vary in monotonic manner from the equatorial plane of the tire as far as the edges of the working layer.
7- A tire according to claim 4 or 5, wherein the angles of the portions vary by stages from the equatorial plane of the tire as far as the edges of the working layer.
8- A tire according to claim 1, wherein the crown reinforcement structure comprises at least two layers of reinforcement elements and wherein from one layer to the next the portions form between them angles of between 20 and 160°.
9- A tire according to claim 1, wherein the reinforcement elements of the carcass-type reinforcement structure form an angle of between 65° and 90° with the circumferential direction.
10- A tire according to claim 1, wherein the circumferential reinforcement elements are distributed in the transverse direction at a variable pitch.
11- A tire according to claim 10, wherein the distribution pitch for the circumferential reinforcement elements at the centre (crown) of the tread is smaller than at the edges of said layer of circumferential reinforcement elements.
12- A tire according to claim 10, wherein the distribution pitch for the circumferential reinforcement elements at the centre (crown) of the tread is larger than at the edges of said layer of circumferential reinforcement elements.
13- A tire according to claim 10, wherein the value of the pitch in the transverse direction follows a mathematical progression increasing over at least part of the axial width of said layer.
14- A tire according to claim 10, wherein the value of the pitch follows an arithmetic progression of the type U(n)=Uo+nr, with Uo being between 0.4 mm and 2.5 mm and r being the difference of consecutive terms of the progression, said difference being between 0.001 and 0.1.
15- A tire according to claim 10, wherein the value of the pitch follows a geometric progression of the type U(n)=Uo+rn, with Uo being between 0.4 mm and 2.5 mm and r being the difference of consecutive terms of the progression, said difference being between 1.001 and 1.025.
16- A tire according to claim 1, wherein a layer of circumferential reinforcement elements is positioned at least in part radially to the inside of the radially outermost working layer.
17- A tire according to claim 1, wherein the carcass-type reinforcement structure is made of two half-plies extending from the shoulders to the beads.
18- A tire according to claim 1, wherein the working layer reinforcement elements are of textile material.
19- A tire according to claim 1, wherein the working layer reinforcement elements are of metal.
20- A tire according to claim 1, wherein the reinforcement elements of the layer of circumferential reinforcement elements are metal and/or textile and/or glass.
21- A tire according to claim 20, wherein the reinforcement elements of the layer of circumferential reinforcement elements exhibit a modulus of elasticity greater than 6000 N/mm2.