JPH02262404A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To mainly reduce weight of a tire and improve durability at high speed with a simple structure by a method wherein a belt layer placed outside a carcass crown is formed by winding steel cords in spiral. CONSTITUTION:A carcass 6 of a pneumatic tire 1 is formed of two inner and outer layers of plies 6A, 6B which are arranged at a tilt angle of 70 to 90 deg. with respect to the tire equator. A folded end of the inner ply 6A extended by coating a folded end of the outer ply 6B is terminated in the vicinity of the maximum tire width position. A belt layer 7 forms a reference surface S at the time of formation of the belt layer 7 by an intermediate part 15A outer side face of a reinforced layer 15 interposed in a floated part of its end and a crown outer side face of the carcass 6. On the reference surface S, an appropriate number of steel cords 16 are wound in spiral in a direction of the tire circumference.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic tire that can reduce the weight of the tire and improve high-speed durability.

(Conventional technology) In recent years, a strong belt layer has been placed on the outside of the crown of the carcass to increase tread rigidity, resulting in improved wear resistance.
Radial tires are widely used due to their improved stability and high-speed durability.

In addition, in order to obtain a sufficient hoop effect and high tread rigidity, the belt layer was conventionally formed by laminating a large number of parallel steel cords, usually 2 to 4 fabrics. .

[Problems to be Solved by the Invention] However, conventional belt layers using such a large number of fabricators have a large difference in rigidity at the ends and have poor rubber adhesion at the ends of the cords, making it difficult to run at high speeds and under high loads. At times, edge peeling tends to occur, and high-speed durability is greatly reduced due to an increase in internal heat generation as the tread gauge thickness increases.

Moreover, this type of tire increases the weight of the tire, impairing fuel efficiency, and also has the problem that the rigidity distribution of the tread portion becomes non-uniform.

The present invention is based on forming a belt layer by spirally winding a steel cord, and aims to provide a pneumatic tire that can solve the above-mentioned problems.

[Means to solve the problem]

In order to achieve the above object, the pneumatic tire of the present invention has the following features:
A toroidal-shaped carcass consisting of one or more plies using cords arranged at an angle of 70 to 90 degrees with respect to the tire equator and secured by folding both ends around a pair of bead cores; and a belt layer disposed outside the crown portion of the carcass, and the belt layer is formed by spirally winding a steel cord.

[Effect]

Since the steel cord wound spirally in this way is restrained in the direction of the cord core, it can effectively bear external forces, and the tread of the two plies is comparable to that of the conventional multiple fabricator. It can exhibit rigidity and a hoop effect, making it possible to reduce the weight of the tire and the thickness of the tread gauge.

In addition, since there is no cut edge at the ply end, it has excellent adhesion to rubber, and there is little difference in rigidity at the end, so it suppresses internal heat generation due to the reduction of tread gauge thickness.
High-speed durability can be greatly improved. In addition, the improved uniformity reduces rolling resistance and the aforementioned weight reduction contributes to improved fuel efficiency.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, the pneumatic tire 1 includes a pair of bead portions 3.3 through which the bead core 2 passes, a sidewall portion 4.4 extending radially outward from the bead portions 3, and a tread portion 5 joining the upper ends of the sidewall portions 4.4. The radial tire for a passenger car is provided with a radial tire for a passenger car, in which both ends of the main body part passing through the tread part 5 and the sidewall part 4 are connected to the bead core 2 between the tread parts 3 and 3.
A toroidal carcass 6 folded from the inside to the outside around the frame is passed over the frame, and a belt layer 7 is arranged on the outside of the crown part of the carcass 6 on the tread part 5.

Furthermore, a bead apex 9 made of hard rubber is provided between the main body part and the folded part of the carcass 6 to increase the lateral rigidity of the tire. A chafer 14 for preventing rim displacement is provided between the carcass 6 and the clinch apex 13.

In this example, the carcass 6 is formed from two layers of inner and outer plies 6A and 6B in which carcass cords made of polyester fibers are arranged at an angle of inclination of 70 to 90 degrees with respect to the tire equator, and the folded end of the outer ply 6B is The folded end of the inner ply 6A that extends over the tire terminates near the tire maximum width position.

In this way, the carcass 6 has its ends terminated at different height positions and is formed in a high turn-up structure, thereby alleviating stress concentration and increasing the rigidity from the bead portion 3 to the sidewall portion 4. . In addition to the Naori-cascord, nylon fibers, steel fibers, etc. can also be used depending on the conditions of use.

The belt layer 7 has a width of 70 to 95% of the width of the tread and is composed of one ply layer disposed outside the carcass 6, and the belt N7 is formed by curving the carcass 6 into an arc at a part of the shield. Its edge rises from the carcass 6,
In this raised part, the clinch apex 13
A reinforcing layer 15 made of hard rubber that rises from the sidewall portion 4 and forms the sidewall portion 4 is interposed therebetween. Note that the outer surface of the intervening portion 15A of the reinforcement R15 interposed in this raised portion constitutes a flat reference surface S that serves as a reference when forming the belt layer 7, together with the outer surface of the crown portion of the carcass 6, and this reference surface S
The belt N7 is formed by winding one or more steel cords 16 spirally along the circumferential direction of the tire.

Since such a steel cord 16 continuously covers the shoulder circumference of the carcass 6, it can effectively bear the external force received from the tread portion, and has approximately the same level of strength as a conventional belt layer consisting of multiple fabricators. It not only provides a hoop effect and tread rigidity, but also improves tire uniformity by reducing discontinuous sections. Also, since this product does not have cut edges at the ply ends, it has excellent rubber adhesion at the ends, and together with the suppression of internal rubber heat generation due to the reduction in tread gauge thickness due to the -layer ply, it can be used at high speeds. The durability can be improved to a large extent.

Furthermore, fuel efficiency can be improved by reducing tire weight and reducing rolling resistance due to the improvement in uniformity.

In addition to ordinary steel cords, the steel cord 16 may include a core material 20 made of unvulcanized rubber mixed with natural rubber or the like and sulfur, as shown in FIGS. 2(a) to 2(c). , e.g. 70C*, JI SG3502
A plurality of 21 filaments made of steel such as WSR3IA and stretched to a diameter of 0.1 to 0.5 m were attached to each tire.
Those twisted together at a pitch of 2 to 20 m with substantially equal circumferential gaps d between the strands can be suitably used.

Note that the filament 21 has a surface coated with Cu, for example.
Tread rubber 1 coated with Su, Zn, or an alloy containing Nl and CO and covering the periphery thereof.
Improves adhesion with 7.

The steel cord 16 is formed by twisting 21 filaments around the core material 20 with a gap d in between.
The permeation of the tread rubber 17 during the vulcanization process is an object, and the permeated tread rubber 17 adheres to the core material 20, thereby making the adhesion between the filament 21 and the rubber more reliable. Furthermore, since each filament 21 has a gap d, it can be bent without rubbing against each other during repeated deformation, eliminating heat generation, wear, and stress caused by the misalignment, and improving durability.

FIG. 3 shows a sectional view of a pneumatic tire for use in small trucks, which is another embodiment of the present invention.

In the figure, the pneumatic tire covers the crown part of a carcass 6 consisting of three carcass plies with a covering rubber layer 23 extending from the sidewall 4, and a base dress part on a part of the shigolder of the covering rubber 123. By laminating the reinforcing layer 15 extending inward in the axial direction from 24 to 24, an average reference plane S is formed by the outer surface of the reinforcing layer 15 and the outer surface of the crown portion of the covering rubber layer 23. .

On the reference surface S, a belt layer 7 is formed by spirally winding a J-do 16 having, for example, a 3+6 structure.

In addition, since the elongation of the cord in a tire equipped with such a belt layer 7 is extremely small, when shaping by internal pressure filling during vulcanization molding, the tip of the spiral winding is made by winding the steel cord in a wavy manner or Over-twisting is preferred.

〔Concrete example〕

Based on the specifications shown in Section 1's, heavy-duty tires and small truck tires with the structure shown in Fig. 3, and passenger car tires and emergency passenger car tires with the structure shown in Fig. 1 were manufactured as prototypes. and high-speed durability compared with conventional tires that differ only in the belt layer.

The tire strength is the breaking strength of the tread, JISD4
In addition to measuring by a plunge test based on 230, high-speed durability is shown as the upper limit non-destructive speed when the vehicle is run under standard internal pressure and standard load conditions, and the running speed is stepped up in lokm/h increments. There is.

As shown in Table 1, it can be seen that the pneumatic tire of the present invention has excellent high-speed durability.

〔Effect of the invention〕

Like soft soil, the pneumatic tire of the present invention has a belt layer formed by spirally winding steel cords, so the ply of the -layer provides tread rigidity comparable to that of conventional multiple fabrics. It is possible to exert a hoop effect, making it possible to reduce the weight of the tire and the thickness of the tread gauge. In addition, this product has less occurrence of end peeling at the ply ends, and therefore, together with the reduction in the tread gauge thickness, high-speed durability is greatly improved, and
It can have many effects such as improving uniformity and improving fuel efficiency.

Figure 1 is a sectional view showing one embodiment of the present invention, Figure 2 (a)
-(b) are side views and cross-sectional views showing one embodiment of the steel cord, and FIG. 3 is a cross-sectional view showing another embodiment of the present invention.

6... Carcass, 7... Belt layer, 16...
Steel cord.

2li 1 2nd flash (1)) 2nd K(a) 3゜4, Dealing with the person making the amendment Patent applicant address 1-1-1 Tsutsui-cho, Chuo-ku, Kobe Name Name Sumitomo Rubber Industries Subsidiary company representative Akebono Yokoi

Claims (1)

[Claims] 1. A toroidal carcass consisting of one or more plies using cords arranged at an angle of 70 to 90 degrees with respect to the tire equator, and secured by folding both ends around a pair of bead cores; A pneumatic tire comprising: a belt layer disposed outside a crown portion of the carcass; the belt layer being formed by spirally winding a steel cord.