Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Patent
1996-03-15
1997-11-18
Johnstone, Adrienne C.
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
152539, 152542, 152543, 152552, 152553, B60C 1500, B60C 15024, B60C 1504, B60C 1506
Patent
active
056883455
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a tubeless tire with radial carcass reinforcement, intended more particularly for equipping heavy vehicles such a trucks, buses, pneumatic-tired subways, and tractor-trailer units.
Such tires are mounted on two types of rims: so-called drop-center rims having frustoconical seats inclined with respect to the axis of rotation and forming with the axis an angle which may vary from 5.degree. to 15.degree., and flat or substantially flat rims having seats inclined by 0.degree. or 5.degree. with respect to the axis of rotation.
So-called drop-center rims have a mounting groove the diameter of which is definitely smaller than the normal diameter of the rim. This inside diameter of the rim is considered by the users to be too small and it does not permit selecting brake drums of dimensions suitable for an effective braking of increasingly more powerful vehicles.
It is therefore highly desirable to increase the diameter of the rim base, and do so insofar as possible without increasing the overall diameter of the rolling assembly, which means decreasing the aspect ratio H/S of the tire, H being the height of the tire on the rim and S its maximum axial width.
In other cases, it is advantageous to decrease the overall diameter of the rolling assembly formed of the tire and the rim without decreasing the diameter of the rim and, in particular, for the purpose of lowering the center of gravity of trailers or semi-trailers. A tire whose aspect ratio H/S decreases while retaining substantially the standard maximum axial width represents one solution to the above problem.
The development of heavy vehicle tires with aspect atios of less thin 0.8 is very difficult. In particular, the life of the beads clearly becomes less as the ratio H/S decreases, the insufficiencies in life being located, in particular, at the level of the ends of the turn-ups of the carcass reinforcement or the ends of the reinforcement plies located in the beads of the tire, the architecture of the beads being an ordinary architecture with, in each bead, a carcass reinforcement turn-up and reinforcement plies the meridian profiles of which are substantially parallel to the meridian profile of the carcass reinforcement in the region of the beads. Furthermore, such an architecture results in a substantial lack of comfort, which is entirely unacceptable for long runs on more or less bumpy roads.
EP 077 161 describes a tire carcass reinforcement which is wound from the outside to the inside of said bead ring and an elastic annular element of rubber placed axially and radially on the inside of the bead ring. In order that the bead, and more particularly, the annular element, can, by rotation around the bead ring, place the carcass reinforcement under tension, the bead seat is more inclined with respect to a parallel to the axis of rotation than the rim seat.
SUMMARY OF THE INVENTION
The invention proposes to remedy these drawbacks, and it concerns a tire having a ratio of less than 0.8 and a radial carcass reinforcement radially over which there is a crown reinforcement, the carcass reinforcement being formed of at least one ply of cords or cables and being wound in each bead around an anchoring bead ring going from the outside to the inside in order to form a turn-up, characterized by the fact that the turn-up is located on the inside of an angle a, open axially towards the inside and radially towards the outside, of at most 45.degree. and defined by two straight lines OD.sub.1 and OD.sub.2 tangent to the circle circumscribed around the anchoring bead ring, the straight line closest to the axis of rotation being parallel to the axis.
The meridian profile of the turn-up may be linear; it is preferably curved with a single radius of curvature and a center of curvature located radially towards the inside. Likewise, this meridian profile, axially at the level of the end of the turn-up, will be tangent to a parallel to the axis of rotation.
It is also advantageous for the carcass reinforcement turn
REFERENCES:
patent: 4185676 (1980-01-01), Raluy
patent: 4580610 (1986-04-01), Jackson
patent: 4794968 (1989-01-01), Griffiths et al.
patent: 5070921 (1991-12-01), Wada et al.
Compagnie Generale Des Etablisse-ments Michelin-Michelin & Cie
Johnstone Adrienne C.
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