Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Patent
1998-08-19
2000-07-04
Johnstone, Adrienne C.
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
152526, 152527, 152531, 152532, 152534, B60C 304, B60C 918, B60C 920, B60C 922
Patent
active
060824255
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a tire with radial carcass reinforcement anchored in each bead to at least one bead wire, and comprising a crown reinforcement formed by at least two so-called working plies, superposed and formed of reinforcing elements which are parallel to each other in each ply and are crossed from one ply to the next, forming angles of at most 40.degree. in absolute value with the circumferential direction of the tire.
U.S. Pat. No. 4,688,615 describes a crown reinforcement for a radial tire composed of a first ply and of a second ply formed by cables parallel to each other in each ply, crossed from one ply to the next, forming an angle with the circumferential direction of the tire that can range between 5 and 60.degree.. A third ply of circumferentially arranged cables is placed between said two plies, those cables having a diameter at most equal to the diameter of the cables of the first and second plies, and being made of a material having a tensile strength less than the tensile strength of the material forming the cables of the first and second plies, which imparts a lesser tensile strength to said third ply, and being more extensible than each of the plies with crossed cables, said third ply being no wider than the ply of cords with the widest angle.
French Application FR 94/15,736, corresponding to U.S. Pat. No. 5,738,740 relates to a tire as described above, and more particularly to a heavy vehicle tire, the ratio of the height above rim H to the maximum axial width S of which is at most 0.60. Said application, in order to improve the life of the crown reinforcement of such a tire, and also the regularity of wear of the tread thereof, requires an architecture of the crown reinforcement characterized by the combined presence in said reinforcement of an axially continuous ply formed of inextensible metal reinforcing elements forming an angle of at least 60.degree. with the circumferential direction of the tire, and a ply of metallic elements oriented substantially parallel to the circumferential direction, arranged radially between the two working crown plies.
Such an architecture makes it possible to obtain better resistance to separation between working plies, and also better fatigue strength of the cables of the carcass reinforcement located beneath the crown reinforcement thus formed. The axial width of the additional ply of circumferential reinforcing elements may be less than the widths of the working plies.
Since the operating temperatures in the tires of form ratio of at least 0.50 are not negligible, Applicant's research has led him to look for a solution which is more effective from the thermic and economic points of view.
In order to improve the life of the crown reinforcement and subjacent carcass reinforcement of a tire, without using a crown ply formed by metal cables very greatly inclined relative to the circumferential direction of the tire and located radially above the carcass reinforcement, the present invention proposes a more economic solution than that described in the above French application.
The tire having an H/S form ratio of at least 0.50, according to the invention, comprises a radial carcass reinforcement and a crown reinforcement composed of at least two working crown plies made of inextensible metal cables, crossed from one ply to the next, forming angles of between 10.degree. and 45.degree. with the circumferential direction, of a protective crown ply formed of elastic metallic cables made of steel oriented relative to the circumferential direction at an angle of the same direction as the angle formed by the cables of the radially outermost working crown ply, and of an additional ply which is axially continuous and formed of metallic reinforcing elements made of steel oriented substantially parallel to the circumferential direction, the additional ply being arranged above the radially closest working ply to the carcass reinforcement, the presence of a crown ply formed of metallic elements oriented relative to the circumferent
REFERENCES:
patent: 3667527 (1972-06-01), Magistrini et al.
patent: 3703202 (1972-11-01), Maiocchi
patent: 4526217 (1985-07-01), Maeda et al.
patent: 4688615 (1987-08-01), Lee
patent: 5738740 (1998-04-01), Cluzel
Compagnie Generale des Etalissements Michelin - Michelin & Cie
Johnstone Adrienne C.
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