Optimal body ply shape for a tire
AssigneesCompagnie Generale Des Etablissements Michelin, Michelin Recherche et Technique S.A.
InventorsBill Clayton, Daniel McEachern Hicks, Timothy B. Rhyne
Life of this patent
Estimating the term…
Abstract
A tire having uniform inflation growth is provided. The tire includes a body ply that is displaced from the conventional equilibrium curve along the bead, sidewall, and shoulder portions of the tire in a manner that provides more uniform inflation growth from bead portion to bead portion. Such construction reduces load sensitivity, reduces or eliminates the tire break-in period, and/or decreases the propensity for cracking—particularly along a groove bottom of the tread in the shoulder.
Claims20
A tire defining a radial direction, an axial direction, and a tire centerline, the tire comprising:
- a pair of opposing bead portions;
- a pair of opposing sidewall portions connected with the opposing bead portions;
- a crown portion connecting the opposing sidewall portions;
- at least one body ply extending between the bead portions and through the sidewall and crown portions, the body ply having a curve along a meridian plane, wherein s is the length in mm along the curve from centerline of the tire;
- and
- one or more belt plies positioned in the crown portion, wherein sM is one-half of the maximum curvilinear width, along the axial direction, of the widest belt of the one or more belt plies having an angle α in the range of −80 degrees≦α≦+80 degrees with respect to an equatorial plane of the tire;
- and
- wherein when a basis curve having three points of tangency p, d, and q is constructed for the body ply, along at least one side of the tire centerline the body ply has
- i) a deviation D(s) from the basis curve in the range of −4.25 mm≦D(s)≦0.5 mm at a point P1=0.13sq+0.87sm−56.6 mm, and
- ii) a deviation D(s) from the basis curve in the range of −0.5 mm≦D(s)≦1.25 mm at a point P2=0.8sq+0.2sm−13 mm;
- where sq is the length along the curve of the basis curve at which point q occurs.
A method of tire construction, the tire including a centerline and a pair of opposing bead portions, a pair of opposing sidewall portions connected with the opposing bead portions, a crown portion connected with, and extending along an axial direction between, the opposing sidewall portions, at least one body ply extending between the bead portions and through the crown portion and sidewall portions, at least one belt ply located in the crown portion, the at least one belt ply being the widest belt ply along the axial direction of the tire having an angle α in the range of in the range of −80 degrees≦α≦+80 degrees with respect to an equatorial plane of the tire, the method of tire construction comprising the steps of:
- creating a model of the tire that includes a reference curve representing the shape of the body ply along a meridian plane when the tire is inflated to a reference pressure, wherein s is a length in mm along the reference curve from a centerline of the tire;
- constructing a basis curve for the tire based upon the reference curve of the tire at the reference pressure, the basic curve having three points of tangency p, d, and q;
- creating a target reference curve for the shape of the body ply along the meridian plane by repositioning the reference curve to have, along at least one side of the tire centerline,
- i) a deviation D(s) from the basis curve in the range of −4.25 mm≦D(s)≦0.5 mm at a point P1=0.13sq+0.87sm−56.6 mm, and
- ii) a deviation D(s) from the basis curve in the range of −0.5 mm≦D(s)≦1.25 mm at a point P2=0.8sq+0.2sm−13 mm;
- where sq is the length along the curve of the basis curve at which point q occurs.
Dependencies are inferred from the claim text.