Pneumatic tire
AssigneeThe Yokohama Rubber Co., Ltd.
InventorKenji Horiuchi
Life of this patent
Estimating the term…
Abstract
In a pneumatic tire, a height from a turned-up edge of a carcass layer is not more than 10 mm, a distance from a tire outer surface to the carcass layer is not less than 50% of the total gauge, a height of the bead filler is from 50% to 80% of a tire cross-section height, a cross-sectional area ratio VB/VR of the bead filler to a side reinforcing layer is not less than 0.4 and not more than 0.6, a hardness HsB of the bead filler is not less than 65 and not more than 80, and the hardness HsR of the side reinforcing layer is not less than 75 and not more than 85, a size relationship between the hardness HsB and the hardness HsR is HsB≦HsR, a value TB of tan δ is not more than 0.06, and a value TR of tan δ is not more than 0.05.
Claims14
A pneumatic tire comprising at least one layer of carcass layer mounted between a pair of left and right bead portions, the carcass layer being folded from the tire inside to the tire outside around bead cores disposed in each bead portion, a bead filler constituted by a rubber composition being disposed on an outer circumferential side of the bead cores, and a plurality of belt layers being disposed on an outer circumferential side of the carcass layer in a tread portion, a plurality of belt cover layers being disposed on an outer circumferential side of the belt layers, and a falcated cross-section side reinforcing layer being disposed inward in a tire width direction of the carcass layer in side wall portions;
- wherein
- a height HT from a turned-up edge of the carcass layer to an outer edge in a tire radial direction of the bead core is not more than 10 mm;
- when fitted to a rim, on an imaginary line L drawn from an outermost edge in the tire radial direction of a region in contact with a rim flange normal to a tire inner surface, a distance GO from a tire outer surface to the carcass layer is not less than 50% of a total gauge GT of the side wall portion on the imaginary line L;
- a height HB of the outer edge in the tire radial direction of the bead filler is from 50% to 80% of a tire cross-section height SH;
- a ratio VB/VR of a cross-sectional area VB of the bead filler to a cross-sectional area VR of the side reinforcing layer is not less than 0.4 and not more than 0.6;
- a hardness HsB at 20° C. of the rubber composition of the bead filler is not less than 65 and not more than 80;
- a hardness HsR at 20° C. of the rubber composition of the side reinforcing layer is not less than 75 and not more than 85, the hardness HsB and the hardness HsR satisfy the relationship HsB≦HsR;
- a dynamic elastic modulus E′B at 60° C. of the rubber composition of the bead filler is not less than 7.0 MPa and not more than 15.0 MPa;
- a dynamic elastic modulus E′R at 60° C. of the rubber composition of the side reinforcing layer is not less than 7.0 MPa and not more than 15.0 MPa;
- a value TB of tan δ at 60° C. of the rubber composition of the bead filler is not more than 0.06;
- a value TR of tan δ at 60° C. of the rubber composition of the side reinforcing layer is not more than 0.05;
- and
- the side reinforcing layer is constituted by two types of rubber compositions having different dynamic elastic moduli at 60° C. that are laminated in the tire radial direction;
- and a dynamic elastic modulus E′RO at 60° C. of the rubber composition of an outer diameter side side reinforcing layer located on the outer side in the tire radial direction and the dynamic elastic modulus E′RI at 60° C. of the rubber composition of an inner diameter side side reinforcing layer located on an inner side in the tire radial direction satisfy the relationship E′RO<E′RI.
A pneumatic tire comprising at least one layer of carcass layer mounted between a pair of left and right bead portions, the carcass layer being folded from the tire inside to the tire outside around bead cores disposed in each bead portion, a bead filler constituted by a rubber composition being disposed on an outer circumferential side of the bead cores, and a plurality of belt layers being disposed on an outer circumferential side of the carcass layer in a tread portion, a plurality of belt cover layers being disposed on an outer circumferential side of the belt layers, and a falcated cross-section side reinforcing layer being disposed inward in a tire width direction of the carcass layer in side wall portions;
- wherein
- a height HT from a turned-up edge of the carcass layer to an outer edge in a tire radial direction of the bead core is not more than 10 mm;
- when fitted to a rim, on an imaginary line L drawn from an outermost edge in the tire radial direction of a region in contact with a rim flange normal to a tire inner surface, a distance GO from a tire outer surface to the carcass layer is not less than 50% of a total gauge GT of the side wall portion on the imaginary line L;
- a height HB of the outer edge in the tire radial direction of the bead filler is from 50% to 80% of a tire cross-section height SH;
- a ratio VB/VR of a cross-sectional area VB of the bead filler to a cross-sectional area VR of the side reinforcing layer is not less than 0.4 and not more than 0.6;
- a hardness HsB at 20° C. of the rubber composition of the bead filler is not less than 65 and not more than 80;
- a hardness HsR at 20° C. of the rubber composition of the side reinforcing layer is not less than 75 and not more than 85, the hardness HsB and the hardness HsR satisfy the relationship HsB≦HsR;
- a dynamic elastic modulus E′B at 60° C. of the rubber composition of the bead filler is not less than 7.0 MPa and not more than 15.0 MPa;
- a dynamic elastic modulus E′R at 60° C. of the rubber composition of the side reinforcing layer is not less than 7.0 MPa and not more than 15.0 MPa;
- a value TB of tan δ at 60° C. of the rubber composition of the bead filler is not more than 0.06;
- a value TR of tan δ at 60° C. of the rubber composition of the side reinforcing layer is not more than 0.05;
- and
- the bead filler is constituted by two types of rubber compositions having different dynamic elastic moduli at 60° C. that are laminated in the tire radial direction;
- and a dynamic elastic modulus E′BO at 60° C. of the rubber composition of an outer diameter side bead filler located on the outer side in the tire radial direction and a dynamic elastic modulus E′BI at 60° C. of the rubber composition of an inner diameter side bead filler located on an inner side in the tire radial direction satisfy the relationship E′BO<E′BI.
Dependencies are inferred from the claim text.