Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Patent
1997-05-29
1998-12-15
Johnstone, Adrienne C.
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
152539, 152542, 152550, 152552, 152553, B60C 1500, B60C 1506
Patent
active
058491171
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a tire with radial carcass reinforcement without independent inner tube and, more particularly, a tire intended for the equipping of heavy vehicles such as trucks, subway trains, and tractor-trailer combinations.
Such tires are mounted on two types of rim, namely: the so-called drop center rims having frustoconical seats inclined with respect to the axis of rotation and forming with said axis an angle which may vary between 5.degree. and 15.degree., and rims with flat or substantially flat base, having seats inclined either by 0.degree. or 5.degree. with respect to the axis of rotation.
The so-called drop center rims comprise a mounting groove the diameter of which is definitely less than the nominal diameter of the rim. This inside diameter of the rim is considered by the users to be too small and it does not make it possible to select brake drums of dimensions suitable for an effective braking of an increasingly more powerful vehicle.
It is therefore highly desirable to increase the diameter of the rim base and, insofar as possible, to do so without increasing the overall diameter of the rolling assembly, which is equivalent to lowering 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 by the tire and the rim without decreasing the diameter of the rim and, in particular, in order to lower the center of gravity of the trailers or semi-trailers pulled. A tire whose aspect ratio H/S decreases while retaining substantially the standard maximum width represents a solution to the above problem.
The development of heavy vehicle tires with aspect ratios of less than 0.8 is very difficult; in particular, the overall strength of the beads becomes definitely less as the ratio H/S decreases, the inadequacies in strength being present at the level of the ends of turn-ups of the carcass reinforcement or the ends of reinforcement plies located in the beads of the tire, the architecture of said 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 zone of said beads. Furthermore, such an architecture results in a substantial lack of comfort, which is particularly disagreeable upon long trips on relatively rough roads.
U.S. Pat. No. 5,688,345 proposes remedying such drawbacks. It concerns a tire the radial carcass reinforcement of which is wound in each bead around the bead ring going from the outside to the inside of the tire so as to form a turn-up which, seen in meridian section, is located within an angle defined by two half lines tangent to the bead ring, the half line closest to the axis of rotation being parallel to said axis and said angle being at most equal to 45.degree..
For reasons of economy, such a turn-up is arranged in an axially inner protuberance of the tire. While an actual saving is obtained with respect to the material, the manufacture of such a tire, which takes longer, is more complicated requires greater precision and is expensive.
SUMMARY OF THE INVENTION
In order to reduce the industrial cost of manufacture, the present invention proposes a tire with radial carcass reinforcement surmounted radially by a crown reinforcement, the carcass reinforcement being composed of at least one ply of threads or cords and being turned up in each bead around an anchoring bead ring going from the outside to the inside so as to form a turn-up, said turn-up being reinforced by at least one additional reinforcing ply of cords oriented at an angle between 0.degree. and 20.degree. with respect to the circumferential direction, the value 0.degree. being included within said range, which is characterized by the fact that the meridian profile of the said reinforced turn-up is linear and substantially parallel to the meridian prof
REFERENCES:
patent: 4580610 (1986-04-01), Jackson
Patent Abstracts of Japan, vol. 017 No. SYI (M-1488), 29 Sep. 1993 & JP, A, 5-147413 (Sumitomo Rubber Ind Ltd), 15 Jun. 1993.
Compagnie Generale des Etablissements Michelin--Michelin & Cie
Johnstone Adrienne C.
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