Run flat tire and method for manufacturing same
AssigneeSumitomo Rubber Industries, Ltd.
InventorHiroaki KAJITA
Life of this patent
Estimating the term…
Abstract
A side reinforcing rubber layer includes a second rubber portion having a modulus constant between a boundary surface and a bead portion and larger than a first rubber portion arranged on a tread-portion-2 side. The boundary surface intersects outer and inner surfaces of the side reinforcing rubber layer at first and third points, respectively. The first and third points are arranged on the bead-portion side of second and fourth points, respectively, which are closest points to an outer end of a belt layer of the outer and inner surfaces, respectively. A distance between an inner end of the first rubber portion and the second point is larger than a distance between the second point and the first point.
Claims20
A run flat tire comprising:
- a carcass extending between a pair of bead cores of bead portions via a tread portion and a pair of sidewall portions,
- a belt layer formed by a plurality of belt plies arranged outside the carcass in a tire radial direction within the tread portion, and
- a pair of side reinforcing rubber layers each arranged inside the carcass in each of the sidewall portions and having a substantially crescent cross-sectional shape,
- wherein
- each of the side reinforcing rubber layers comprises a first rubber portion arranged on a side of the tread portion and a second rubber portion connected with the first rubber portion so as to have a boundary surface therebetween, extending from the boundary surface toward the adjacent bead portion, and having a modulus larger than the first rubber portion and constant between the boundary surface and the adjacent bead portion,
- in a tire meridian section passing through a tire rotational axis and in each of the side reinforcing rubber layers,
- a first point where the boundary surface intersects with an outer surface of the side reinforcing rubber layer in a tire axial direction is arranged on a side of the adjacent bead portion in the tire radial direction of a second point of the outer surface which is a closest point to an outer end of the belt layer in the tire axial direction,
- a third point where the boundary surface intersects with an axially inner surface of the side reinforcing rubber layer is arranged on a side of the adjacent bead portion in the tire radial direction of the first point and a fourth point which is a closest point of the axially inner surface to the outer end, and
- a distance L1 along the outer surface between an axially inner end of the first rubber portion and the second point is larger than a distance L2 along the outer surface between the second point and the first point.
Dependencies are inferred from the claim text.