The invention relates to a belt structure for a pneumatic tire, and more particularly to a belt structure having belt edge strips that are reinforced with square woven fabric.
As used in this disclosure and the appended claims with reference to a tire, the term "circumferential" should be understood as referring to the directions around the circumference of the tire. The terms "axial" and "axially" should be understood as referring to the directions parallel to the axis of rotation of the tire and perpendicular to the mid-circumferential plane of the tire. The "mid-circumferential plane" of the tire should be understood as referring to a plane perpendicular to the axis of rotation of the tire located midway between the sidewalls of the tire. The terms "radial" and "radially" should be understood as referring to the directions toward or away from the axis of rotation of the tire.
Reinforcing belt structures in tires are sometimes subject to a phenomenon known as "belt edge separation". Belt edge separation occurs when the axial edges of the belt plies become displaced from their preferred positions during operation of the tire and thus become separated from the underlying carcass-reinforcing ply, an adjacent belt ply, or overlying tread material. Various solutions have been suggested to eliminate belt edge separation. For example, U.S. Pat. No. 4,184,530 teaches the use of cap plies or strips having cords from a synthetic material having a low modulus of elongation overlapping an edge region of a belt ply, with the cords extending in a circumferential direction only: U.S. Pat. No. 3,598,165 teaches an elastomeric strip surrounding the belt edges with a fabric overlay on top of the strip; U.S. Pat. No. 4,062,393 teaches a body of rubber having a Shore A hardness of between 70 and 80 positioned to cover the belt edges: and Canadian Pat. No. 1,035,682 teaches the use of uncalendered square woven fabric as belt edge strips.
There is provided in accordance with one aspect of the present invention a radial tire comprising a tread portion and an annular belt structure underlying said tread portion, said annular belt structure comprising a plurality of radially superposed belt plies and a pair of axially spaced apart edge strips of leno weave fabric, a portion of each edge strip being disposed between a pair of belt plies that are adjacent to one another.
These and other features of the present invention can be better understood from the following detailed description of the preferred embodiments, when read in conjunction with the accompanying drawings.