Run flat tire
AssigneeThe Yokohama Rubber Co., Ltd.
InventorKenji Horiuchi
Life of this patent
Estimating the term…
Abstract
A run flat tire in which the maximum tire width position when the tire is in an inflated state, the inclination angle formed by the line S′ tangent to the tire outer wall in the tire shoulder region, the curving form of the tread surface, the relationship between the thickness Ga of the outer side rubber taken on a line X normal to the rim line and centered on the carcass layer 5 and the maximum thickness Gb of the outer side rubber in an upper region of the bead portion 2, the relationship of the thickness Gc of the inner side rubber taken on a line X normal to the rim line and centered on the carcass layer 5 and the thickness Ga of the outer side rubber are each stipulated.
Claims18
A run flat tire comprising at least one layer of a carcass layer provided around bead cores embedded in a left-right pair of bead portions and folded over from a tire inner side toward a tire outer side so as to envelop bead fillers that are disposed on an outer circumferential side of the bead cores, wherein a plurality of belt layers is disposed on an inner circumferential side of a tread portion, a belt cover layer formed from organic fiber cords is disposed on the outer circumferential side of the belt layers, and a side reinforcing layer having a falcated cross-section is disposed between the carcass layer and an inner liner layer in a side wall portion;
- wherein
- a relationship between a tire cross-sectional height SHi on an inner side in the tire radial direction and a tire cross-sectional height SHo on an outer side in the tire radial direction, demarcated by a maximum tire width position when the run flat tire is assembled on a JATMA regulation standard rim and inflated to an air pressure of 180 kPa, is 0.7<SHi/SHo<0.9;
- an intersection P of
- a line tangent to an intersection S of a straight line Q in a tire axial direction passing through a midpoint of the tire cross-sectional height SHo and a tire outer wall and
- an external tire diameter line Z
- is positioned more to a tire equatorial plane side than a region R that corresponds to 90% of a rim width HRW of the standard rim having the tire equatorial plane as a center;
- an angle α of a straight line connecting, in the tread surface, a point O on the tire equatorial plane and a point R′ on a shoulder side corresponding to 110% of a tire ground contact width TW having the tire equatorial plane as a center, with respect to the tire axial direction, is from 7.5 to 10°;
- the outer peripheral edge of the bead filler is positioned more to the inner side in the tire radial direction than a line normal to a rim line on an outer wall surface of the bead portion;
- when Ga is a rubber thickness taken on a line normal to the rim line between the carcass layer and an outer wall surface of the side wall portion, and Gb is a maximum rubber thickness taken on a line normal to the carcass layer between the carcass layer and the outer wall surface of the side wall portion, a relationship between Ga and Gb is 0.65 Gb<Ga<0.85 Gb;
- and
- when Gc is a rubber thickness taken on a line normal to the rim line between the carcass layer and a tire inner wall surface, a relationship between Gc and Ga is 0.85 Ga<Gc<1.00 Ga.
Dependencies are inferred from the claim text.