JPS5816883Y2 - Radial tires suitable for high speed driving - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a radial tire especially for high-speed running, which is provided with a belt layer made of metal cords as a reinforcing material.

As a belt layer for radial tires for high-speed running.

Since French Patent No. 1,228,241 proposed a structure in which a fly in which metal cords are arranged at a small angle with respect to the circumferential direction of the tire is folded at both ends, various deformed structures have been developed.

The feature of the folding structure of the belt layer is that the circumferential rigidity of both ends of the belt layer is significantly higher than that of simply stacking multiple belt plies (sheets) with a predetermined width, so it is more effective in terms of the effective reinforcement width. It is to be advantageous.

However, on the other hand, because the folding edges of the folding belt ply are located corresponding to both side edges of the tread, which are exposed to the most severe conditions for the tire, the excessive stress that is applied to that part during driving causes the metal cord to bend prematurely. Easy to break due to fatigue.

As a precautionary measure to reduce premature fatigue of the metal cord at the bending position, the other metal cord ply is tucked into the width groove, and the radius of curvature of the edge is reduced by the thickness of this folded ply at the bending position. In the case of a larger structure or as in Japanese Utility Model Application Publication No. 53-72307, the radius of cross-sectional curvature of the folded edge can be increased without enclosing another ply as described above by applying a very thin metal cord as the folded ply. Also known are so-called 180' close fold structures, which are virtually equal to the thickness of the ply.

Among the above measures, the former is unfavorable in terms of riding comfort because the rigidity of the belt layer becomes too high, while the latter is not preferable in terms of ride comfort, while the latter is the result of minimizing the radius of curvature of this part instead of the folded edge of the folded ply. There is a disadvantage that stress becomes excessive, and it is difficult to obtain the expected improvement effect in either case.

This invention proposes a tire with a belt structure that is superior in riding comfort by reducing the stress at the bending position of the folding belt ply.

This invention consists of a radial carcass in the shape of a trot, a nearly cylindrical tread extending along the outer periphery of the carcass, and a belt layer consisting of multiple plies of metal cords arranged at a small angle with respect to the circumferential direction of the tread between these carcass and treads. This belt layer has a folded part on the first ply which is not folded, which is obtained by bending both end areas of the base part with the cord oriented in a direction crossing the metal cord of the first ply, and this bending. The second ply, which limits the maximum width of the belt layer, is overlapped at the turning position, and the first ply is placed around the outer circumference of the radial carcass. In a radial tire stacked in the order of the second ply, the second ply has the folded part facing the bending position from its tip, and the main part of the ply is tightly attached parallel to the base part with the coating rubber applied to the ply. In addition, by filling the inside of the first bending position with a rubber filler of the same quality as the coating rubber, a first bending radius corresponding to - of the substantial total thickness of the laminated belt ply is formed.
This is a radial tire suitable for high-speed running, characterized by having an enlarged part that covers the side edges of the ply and bulges toward the carcass side.

The explanation will be given below based on the drawings.

Fig. 1 shows a cross-sectional view of the improvement of the belt layer according to this invention, and Fig. 2 shows the details by enlarging the end of the belt layer by 1□.

In Fig. 1 □, 1 indicates a tire, 2 indicates a substantially cylindrical tread 2, and from the end 3 of this tread 2, although not shown in the □ figure, the side portion extends inward in the radial direction of the tire.
It has a bead part.

Although only the right side of tire 1 is shown, the equatorial plane of the tire is 0-
Of course, it is symmetrical with respect to 0.

Apply the inner liner 4 between both bead parts according to the usual method.
The body of the tire is reinforced by a radial carcass 5 which is lined with rubber and extends in a toroidal shape.

The radial carcass 5 has, for example, one or more plies coated with rubber on fiber cords and arranged at a cord angle substantially perpendicular to the circumferential direction of the tread 2 (equatorial plane 0-0). On the outer periphery, 1 for the equatorial plane o-0
A belt layer 6 consisting of a plurality of plies in which metal cords are arranged at a small angle of 0' to 25° is attached to a tread 2.
The tread 2 is hardened by disposing it across the 0-width width.

In this invention, the belt layer 6 has a non-folding first ply 6-1 that follows the contour of the carcass 5 but extends in a substantially straight cylindrical shape, and has both end areas folded toward the tread 2 side wider than this first ply. and a second ply 6-2, which are sequentially arranged on the radial carcass. It is laminated with the second ply.

In this case, between the base portions 7 of the first ply 6-1 and the second ply 6-2, the cords are made to intersect left and right at approximately the same angle with respect to the equatorial plane 0-0.

The folded portion 8 of the second ply 6-2 extends substantially parallel to both sides from the tip e facing the equatorial plane 〇-〇.

It consists of a main part 9 that is in close contact with the ply through a coating rubber and an enlarged part 10 that bulges toward the radial carcass 5 at the bending position of the ply. to match the shape of.

It extends substantially parallel to an imaginary line connecting the bottoms of the grooves g carved in the tread 2 in the lateral direction.

The above-mentioned upper surface of the folded portion 8 is directed toward the radial carcass 5 at the bent position and forms an enlarged portion 10 with a small radius of curvature.

As shown in FIG. 2, the thickness i of the enlarged portion 10 is
- approximately equal to the total thickness of the base part 7 and the folded part 8 of the first and second ply, and therefore inside the cavity formed inside the bend.

It is filled with a rubber filler 15 of the same quality as the coating rubber 14 applied to the ply cord 13.

The width j of the enlarged portion 10 is preferably 1 to 3 times its thickness i.

In other words, the bending radius of the bulge forming the enlarged part 10 corresponds to approximately - of the total thickness of the laminated belt ply, and the enlarged part 10
The zero width corresponds to 2 to 6 times the bending radius.

The coating rubber 14 applied to the metal cord 13 of the second braai 6-2 has a modulus of at least 20 when stretched by 50%.
J/air - In particular, it is desirable to have a modulus exceeding 20 and up to 28-X. Therefore, the same modulus range should be applied to the rubber filler 15 in the enlarged part.

Note that the width l of the folded portion 80 is in the range of 15 to 40% of the width of the second ply, which is the maximum width of the belt layer, and as in this embodiment, one metal cord layer is provided on each of the first and second plies. If applicable, the exposed portion of the second ply base portion 7 will be present in the central area.

Further, as shown in FIG. 1, it is possible to apply a cushion rubber 12 having a lower modulus than the adjacent coating rubber 14 from the side of the second ply fattening section 10 to the end of the first ply.

In this case, it is preferable that the modulus is lower than that of the rubber material that is preferably used as the tread rubber 11.

3 and 4 are diagrams showing the cord structure applied to the second ply of the beveled layer and the arrangement direction of the cord.

In FIG. 3a, the strands (
When using a Z-twisted cord (consisting of multiple filaments twisted together), that is, the cord is twisted in the upward direction to the right in the figure.

The cords 13 are arranged in the S direction, that is, in the upward left direction (FIG. 3R), and both end areas are folded in the direction of the arrow shown in FIG. 3C.

On the other hand, when an S-twist cord is used as the cord (FIG. 4a), the cords 13' are arranged in the Z direction (FIG. 4b) and folded in the direction of the arrow (FIG. 4C).

In this way, it is possible to prevent the loosening of the twist that tends to occur due to the structural bending of the cord in the enlarged part of the 21st lie, and it is possible to effectively improve the rigidity of both end regions of the belt layer.

Thus, the tire of this invention has the characteristics of a tire with a folding type belt layer, and improves the ride comfort of the tire by the enlarged effect of the belt layer ends without impairing the rigidity of both end areas of the Alberto layer. Separation failure at the end of the belt layer, which tends to occur in the belt layer, can be effectively suppressed.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part showing an embodiment of this invention, FIG. 2 is an enlarged detailed view of the main part, and FIGS. 3 and 4 a. B and C are explanatory diagrams showing the relationship between the twist of the metal cord, the cord arrangement of the second belt ply, and the direction of bending. 2... Tread, 5... Radial carcass 6... Belt layer, 6-1... First ply, 6-2... 2nd ply, 7...
...Base part, 8...Folding part, 9...
...Main part, 10... Hypertrophic part.

Claims (1)

[Claims for Utility Model Registration] l A toroidal radial carcass, a substantially cylindrical tread extending along the outer periphery of the carcass, and metal cords arranged between the carcass and the treads at a small angle with respect to the circumferential direction of the tread. A belt layer consisting of a plurality of flies is provided, and the belt layer includes a first ply that is not folded, and a base portion having both end regions with the cords oriented in a direction crossing the metal cords of the first ply bent back toward the tread side. The second ply, which has a folded part and limits the maximum width of the belt layer at this folded position, is overlapped with the first ply to the outer circumference of the radial carcass. In a radial tire stacked in the order of the second ply, the second ply bends the folded part from its tip to the bending position, and in addition to the main part, the folded part is brought into close contact parallel to the pace part with the coating rubber applied to the ply. By filling the inside of the turning position with a rubber filler of the same quality as the coding rubber, the belt has a bending radius corresponding to T, which is the substantial total thickness of the laminated belt ply, and bulges toward the carcass side, covering the side edges of the first ply. A radial tire that is suitable for high-speed driving and features an enlarged area. 2. The tire according to claim 1, in which the enlarged portion has a width corresponding to 2 to 6 times its bending radius. 3 Utility model registration claim 1, in which the modulus of the coating rubber and rubber filler applied to the second ply of the belt layer at 50-strand elongation is at least 20 kgA-
Tires listed in section.