Pneumatic tire
View Patent ↗A pneumatic tire includes a tread portion; three or more circumferential direction grooves; width direction grooves; and lines of land portions. When a tread center area and tread shoulder areas are sectioned at centerlines of the circumferential direction grooves in outermost sides in the tire width direction, a ratio G=(A+B)/X of a sum A+B of a groove area A of the circumferential direction grooves and a groove area B of the width direction grooves to a contact area X of the tread portion is in a range of G≦0.25, a ratio S=B/(A+B) of the groove area B to the sum A+B is in a range of 0.25<S<0.45, a ratio Gs=C/Y of a groove area C of the tread shoulder areas to a contact area Y of the tread shoulder areas is in a range of Gs<0.20, and the ratio G and the ratio Gs have a relation of Gs<G.
1. A pneumatic tire comprising:
three or more circumferential direction main grooves that extend in a tire circumferential direction;
a plurality of width direction grooves that extend in a tire width direction; and
a plurality of lines of land portions that are sectioned by the circumferential direction main grooves and the width direction grooves, wherein
the tread portion has a traction pattern formed by the circumferential direction main grooves, the width direction grooves, and the land portions, wherein
when a tread center area and tread shoulder areas are sectioned at centerlines of the circumferential direction main grooves in outermost sides in the tire width direction,
a ratio G=(A+B)/X of a sum A+B of a groove area A of the circumferential direction main grooves and a groove area B of the width direction grooves to a contact area X of the tread portion is in a range of G≦0.25, a ratio S=B/(A+B) of the groove area B of the width direction grooves to the sum A+B of the groove area A of the circumferential direction main grooves and the groove area B of the width direction grooves is in a range of 0.25<S<0.45,
a ratio Gs=C/Y of a groove area C of the tread shoulder areas to a contact area Y of the tread shoulder areas is in a range of Gs<0.20, and
the ratio G and the ratio Gs have a relation of Gs<G, and
wherein a groove depth h1 of the circumferential direction main grooves and a groove depth h2 of the width direction grooves has a relation of h2/h1≧0.30, and a groove width w1 of the circumferential direction main grooves and a groove width w2 of the width direction grooves has a relation of w2/w1≧0.20.
2. The pneumatic tire according to claim 1 , wherein the ratio G is in a range of G≧0.15.
3. The pneumatic tire according to claim 1 , wherein the circumferential direction main grooves includes at least five circumferential direction main grooves.
4. The pneumatic tire according to claim 1 , wherein a groove wall angle θ of at least one of the circumferential direction main grooves is in a range of θ≧8 deg.
5. The pneumatic tire according to claim 1 , wherein a groove wall angle θ of the circumferential direction main grooves varies in the tire circumferential direction.
6. The pneumatic tire according to claim 1 , wherein
the groove depth h1 of the circumferential direction main grooves and the groove depth h2 of the width direction grooves has a relation of h2/h1≦0.70, and
the groove width w1 of the circumferential direction main grooves and a groove width w2 of the width direction grooves has a relation of w2/w1≦0.50.
7. The pneumatic tire according to claim 1 , wherein, when a belt reinforcing layer is arranged in the tread portion, a thickness t of a tread rubber from a groove bottom of the circumferential direction main groove in the tread center area to the belt reinforcing layer is in a range of 3.0 mm≦t≦5.5 mm.
8. The pneumatic tire according to claim 1 , wherein a tan δ of a tread rubber that is obtained when the tread rubber is heated at 100° C. is in a range of 0.01≦tan δ≦0.07.
9. The pneumatic tire according to claim 1 , wherein the pneumatic tire is a heavy load pneumatic radial tire.