Pneumatic tire with geodesic belt
A tire having a modified geodesic belt is described. The ideal geodesic belt path is modified to select the centerline belt angle and to avoid excessive build up of the belt at the belt edges. The method includes the step of calculating the minimum three dimensional distance from one belt edge to the other belt edge preferably using dynamic successive approximation.
1. A pneumatic tire having a carcass and a belt reinforcing structure, the belt reinforcing structure comprising:
a first belt layer having cords arranged at an angle of 5 degrees or less with respect to the midcircumferential plane, and a second belt layer formed of a plurality of geolines joined together, each geoline extending between a first belt edge and a second belt edge, wherein each geoline is tangent to the first belt edge and the second belt edge, and is formed in a three dimensional minimum path, wherein each geoline is formed by calculating a three dimensional minimal distance path L from one belt edge to the other belt edge using the following equation: L=Σ(SQRT(X 2 +Y 2 +Z 2 )), for ψ=0 to AG, Where Z=R*δψ,
wherein the second belt layer is wider than the first belt layer and is located radially outward of the first belt layer.
2. The pneumatic tire of claim 1 wherein the angle at the centerline of is set to a desired value, and the three dimensional minimal distance path L from one belt edge to the other belt edge is determined using the following equation: L=Σ(SQRT(X 2 +V+Z 2 )), for ψ=0 to AG, Where Z=R*δψ.
3. The tire of claim 1 wherein the second belt layer is formed from a continuous strip.
4. The tire of claim 1 wherein the second belt layer is formed from a nylon/aramid strip material.
5. The tire of claim 1 wherein the second belt layer is formed from a nylon material.
6. The tire of claim 1 wherein the second belt layer is formed from an aramid material.
7. The pneumatic tire of claim 1 wherein at least one of the first and second belt layers has cords having a percent elongation at break lesser than about 24%, and a break strength greater than about 400N.
8. The pneumatic tire of claim 1 wherein one or more of the carcass plies comprise cords made of a nylon.
9. The pneumatic tire of claim 1 wherein the carcass ply cords have greater elongation at break than the cords of at least one of the first or second belt layers.
10. The pneumatic tire of claim 1 having a third_belt layer having cords arranged at an angle of 5 degrees or less with respect to the midcircumferential plane.
11. The pneumatic tire of claim 10 wherein the third belt layer is wider than the first belt layer.
12. The pneumatic tire of claim 1 wherein the third belt layer is radially inward of the first belt layer.
13. The pneumatic tire of claim 1 wherein the second belt layer is the widest belt layer.
14. The pneumatic tire of claim 1 wherein the second belt layer is the radially outermost belt.
15. The pneumatic tire of claim 1 wherein the second belt layer has a centerline angle that is selected to be in the range of 15-30 degrees.
16. A pneumatic tire having a carcass and a belt reinforcing structure, the belt reinforcing structure comprising:
a belt layer formed of a plurality of geolines joined together, each geoline extending between a first belt edge and a second belt edge, wherein each geoline is tangent to the first belt edge and the second belt edge, and is formed in a three dimensional minimum path, wherein each geoline is formed by calculating a three dimensional minimal distance path L from one belt edge to the other belt edge using the following equation: L=Σ(SQRT(X 2 +Y 2 +Z 2 )), for ψ=0 to AG, Where Z=R*δψ.