JPH06127211A - Assembly of pneumatic radial tire - Google Patents

Abstract

PURPOSE:To prevent carcuss ply cords from breaking off and also prevent the steering stability of a vehicle from lowering. CONSTITUTION:The angle of cords which form a carcuss ply is 75 to 88 deg. relative to the circumferential direction of a tread, the ends of a carcuss 4 are wound up around the periphery of a bead core from the inside to the outside, and these wound-up ends are positioned at the inner periphery side of a belt layer apart from each other. Also, in a tire shoulder section 7 where a space of 0.5 to 5.0 times a carcuss ply cord diameter is provided between a main body section 4a and a wind-up end section of the carcuss 4, the extending directions of ply cords of the carcuss main body section 4a which are located at the wind-up ends of the carcuss 4 are reversed to each other between two tires relative to the circumferential direction of the tread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combination of pneumatic radial tires, and in particular, it realizes weight reduction of tires while effectively preventing breakage of carcass ply cords. This is to effectively prevent the deterioration of the steering stability of the vehicle.

[0002]

2. Description of the Related Art As a conventional pneumatic radial tire, a carcass is formed by at least one carcass ply composed of carcass ply cords that form substantially 90 ° with respect to the circumferential direction of the tread, and each end of the carcass is formed. There is one in which the parts are wound from the inside to the outside around the bead core, and the winding ends are located at the inner circumference side position of the belt layer with a space between each other. By terminating the winding-up end portion at the position on the inner peripheral side of the belt layer, the tire is lightweight and the rigidity is improved.

[0003]

However, in such a prior art, since the carcass ply cord extends at an angle of substantially 90 ° with respect to the circumferential direction of the tread, the load rolling of the tire, especially The carcass, and eventually the tire, did not have sufficient rigidity during load rolling during turning of the vehicle.

Therefore, the carcass ply cord is extended at an angle smaller than 90 ° with respect to the circumferential direction of the tread,
By crossing the body part cord and the winding end part cord of a carcass consisting of a single carcass ply with each other, the rigidity from the bead part to the tread part is increased, and at the same time, the weight of the tire is reduced. Is proposed.

However, according to this, when the tire rolls under load, especially in the shoulder portion, in other words, in the portion between the portion near the maximum width position of the tire and the portion near the belt side edge, There was a problem that the ply cords of the carcass main part and the ply cords of the winding end parts, which are in different directions from each other, rub against each other, and the carcass ply cord is likely to be broken early, and also the inner circumference of the belt layer On the side, the ply cord of the carcass body portion located between the winding ends of the carcass causes a plysteer component due to the inclination of the ply cord in a specific direction with respect to the tread circumferential direction, impairing the steering stability of the vehicle. There was another problem.

The present invention has been made as a result of investigations aimed at solving the problems of the prior art. The object of the present invention is to reduce the weight of tires and to break the carcass ply cord. It is an object of the present invention to provide a pneumatic radial tire combination which can effectively prevent the above-mentioned phenomenon and can advantageously avoid the influence of price tear.

[0007]

A pneumatic radial tire combination of the present invention comprises a carcass comprising a tread portion, a pair of sidewall portions and a bead portion, and a carcass ply. Two tires, each of which is arranged on the outer peripheral side of the carcass and has at least two belt layers made of respective cords extending so as to intersect with each other and a bead core embedded in each bead portion, one axle, A combination of pneumatic radial tires mounted on at least the front axle, wherein the angle of the cord forming the carcass ply with respect to the tread circumferential direction is 75-
In the range of 88 °, each end of the carcass is wound from the inside to the outside around the bead core, and the respective winding ends are positioned at the inner circumference side position of the belt layer and spaced from each other. As described above, the shoulder portion, that is, the portion between the tire maximum width position vicinity portion and the belt side edge vicinity portion, between the carcass main body portion and the winding end portion, the carcass ply cord diameter of 0.5 to Five.
0 times, preferably located between 0.7 to 3.0 times the distance between the respective carcass winding ends,
The extending direction of the ply cords of the carcass body portion is opposite to the circumferential direction of the tread by the two tires.

Here, an intermediate layer of hard rubber, nylon woven cloth, or the like is provided in the shoulder portion between the carcass main body portion and the winding end portion to more sufficiently contact the carcass ply cords. It is preferable to prevent the increase in bending rigidity of the shoulder portion.

More preferably, in addition to the above, in the two tires located at the front and rear on each side of the vehicle, the plies of the respective winding end portions of the carcass located on the inner peripheral side of the belt layer. The extending directions of the cords are opposite to the tread circumferential direction.

[0010]

[Operation] In this pneumatic radial tire combination,
By forming a carcass that can exhibit sufficient rigidity with a single carcass ply, it is possible to reduce the weight of the tire, and at the shoulder portion of the tire, between the carcass main body part and the winding end part. By setting a distance of 0.5 to 5.0 times the diameter of the carcass ply cord, it is possible to prevent the ply cord of the carcass body part from rubbing against the ply cord of the winding end part when the tire rolls under load. As a result, it is possible to effectively prevent early breakage of the carcass ply cord.

Here, the distance between the carcass body and the winding end is set to 0.5 to 5.0 of the carcass ply cord diameter.
If it is less than 0.5 times, the carcass ply cords cannot be effectively prevented from rubbing against each other.
If it exceeds 5.0 times, the weight will increase significantly, and the merit of weight reduction will be impaired.

Further, when an intermediate layer for enhancing the bending rigidity of the shoulder portion is provided between the carcass body portion and the winding end portion, maneuverability can be greatly improved.

Moreover, in this combination, the extending directions of the ply cords of the carcass main body portion, which are located between the respective winding ends of the carcass, of the two tires mounted on one axle are opposite to each other. As a result, by installing the tire so that the cord direction is line symmetrical with the two tires on the left and right, the price tear component of the tire is canceled by the left and right tires, improving the steering wheel flow of the vehicle and steering stability Can be greatly improved.

Further, the extending directions of the ply cords at the carcass winding end portion located on the inner peripheral side of the belt layer are opposite to each other in the two tires located at the front and rear on each side of the vehicle. In this case, in particular, the function of the tread side end portion, where the ground contact pressure becomes higher than the tread central portion when the vehicle starts and brakes, can be separated by the front and rear wheels. Further, excellent braking force can be exerted on each of the two rear wheels, and as a result, each of the driving force and the braking force can be effectively improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a tread width direction cross-sectional view illustrating a pneumatic radial tire that can be applied to the combination of the present invention. In this example for a tire of size 205/60 R15, 1 is the tread section, 2 is a pair of sidewall sections connected to the tread section 1, and 3
Indicates a bead portion continuous with each side wall portion 2. 4 is a carcass as a frame reinforcing layer,
Reference numerals 5 denote belts arranged on the outer peripheral side of the crown portion of the carcass 4, and the belt 5 is composed of two layers of belts 5a and 5b in this example.

Here, the carcass 4 is formed by one piece of the carcass ply 1 made of a nylon cord of 1260d / 2, which is extended at an angle of 80 ° with respect to the circumferential direction of the tread, and each of the carcass 4 is formed. The end portion is wound around the bead core 6 embedded in the bead portion 3 from the inside to the outside of the tire, and the respective winding ends are positioned at the inner peripheral side position of the belt 5 with a gap therebetween. .

The main body portion 4a and the hoisting end portion 4b of the carcass 4 serve as a carcass ply cord in the shoulder portion 7 which is a portion between the tire maximum width position vicinity portion and the belt side edge vicinity portion. The nylon cords are placed at intervals of 0.5 to 5.0 times, preferably 0.7 to 3.0 times the diameter. By the way, in the illustrated example, the gap is set to 1.5 times.

By the way, a rubber material having a relatively high hardness, for example, a Shore A hardness of 90 degrees is provided as the intermediate layer 8 in such a space between the carcass body portion 4a and the winding end portion 4b. Then, the direct contact of the ply cords of these respective portions is prevented, and at the same time, the bending rigidity of the shoulder portion 7 is increased. As the intermediate layer 8, nylon woven cloth or the like may be used, and relatively soft rubber may be used, provided that the thickness is increased.

Further, here, each belt layer
For each cord of 5a and 5b,
Steel cords extending in mutually opposite directions at an angle of 20 ° are provided, and a bead filler 9 is arranged on the outer peripheral side of the bead core 6 between the carcass body portion 4a and the winding portion 4b. The hardness, the outer end position in the radial direction, etc. of the bead filler 9 can be appropriately selected as required.

In the figure, 10 and 11 respectively represent a general rubber chafer and a canvas chafer,
12 also shows a general inner liner. Also 1b
Indicates a mini-side rubber layer disposed on the tread side end portion, preferably in a non-contact area, and this mini-side rubber layer 1b
Is also preferably composed of the same rubber composition as the sidewall rubber.

FIG. 2 is a plan conceptual view showing an embodiment of the present invention using the above-mentioned tire. This example shows a tire combination example for each of the front and rear two axles with two tires attached, and here, the left and right tires A, B and C, D attached to each axle are shown.
In the inner peripheral side of the belt layer, the extending directions of the ply cords of the carcass body portion 4a located between the winding ends of the carcass 4 are opposite to each other with respect to the tread circumferential direction.

By the way, in this case, the cord extending directions of the left and right tires are made line-symmetrical with respect to the vehicle center line, and depending on load conditions and the like, the line-extending direction is slightly deviated from the line-symmetrical direction. You can also do it.

Here, the tires are mounted so that the cord extending directions of the left and right tires of the respective axles are in an inverted eight-character shape. However, the cord direction is an eight-character shape opposite to the illustrated example. It is also possible to do so.

FIG. 3 is a conceptual plan view showing another example of the combination of tires. In this example, a belt is provided between two tires A, C and B, D located at the front and rear on each side of the vehicle. The extending directions of the ply cords of the carcass winding end portion 4b located on the inner peripheral side of the layer are opposite to the tread circumferential direction.

As a result, in the illustrated combination example, the left and right tires A and B of the front axle have eight-shaped cord extending directions, and the tires C and D of the rear axle have opposite eight-shaped cord extending directions. As a result, the driving force can be increased by the wheels and the braking force can be increased by the rear wheels.

In this case as well, the code direction can be set in the opposite direction to the illustrated example, in which case the rear wheels contribute to the increase of the driving force and the front wheels contribute to the increase of the braking force. It will be.

(Comparative Example) A comparative study on straight running stability, driving and braking performances of a tire combination and a comparison combination according to the present invention will be described below. ◎ Test tire ・ Invention combination 1 Combination shown in Fig. 2 ・ Invention combination 2 Combination shown in Fig. 3 ・ Comparison combination shown in Fig. 4

◎ Test method Straight running stability is evaluated by feeling by conducting a steering test with an actual vehicle. Driving performance is the time required to reach a certain mileage while accelerating, and braking performance is a constant speed. Each braking distance was measured and evaluated.

◎ Test Results The results of these tests are shown in Table 1 by index. In addition,
The larger the index value, the better the result.

[Table 1]

[0030]

As described above, according to the present invention, by providing a space of 0.5 to 5.0 times the diameter of the carcass ply cord between the carcass body portion and the winding end portion at the tire shoulder portion, The breaking durability of the carcass ply cord can be greatly improved, and the extending direction of the ply cord of the carcass main body part is at least opposite to each other between the two tires mounted on the front axle. The generated plysteer component can be offset by those tires, resulting in excellent steering stability.

By the way, in addition to the above, when the extending direction of the ply cord at the winding end of the carcass is opposite between the two front and rear tires located on each side of the vehicle, The drive and braking functions can be separated into front and rear wheels, which results in drive force and
Each of the braking forces can be effectively improved.

[Brief description of drawings]

FIG. 1 is a tread width direction sectional view of a pneumatic radial tire applicable to an embodiment of the present invention.

FIG. 2 is a conceptual plan view showing an example of tire combination.

FIG. 3 is a conceptual plan view showing another combination example of tires.

FIG. 4 is a schematic plan view showing a comparative combination.

[Explanation of symbols]

 1 tread part 2 sidewall part 3 bead part 4 carcass 4a body part 4b hoisting end part 4c hoisting end 5 belt 5a, 5b belt layer 6 bead core 7 shoulder part 8 intermediate layer 13 circumferential groove 14, 15 land part 16, 17 slope Grooves A, B, C, D tires

Claims (2)

[Claims] 1. A carcass comprising a tread portion, a pair of side wall portions and a bead portion, and a carcass formed of a single carcass ply, and arranged on the outer peripheral side of the carcass and extending to intersect each other. A pneumatic radial tire combination in which two tires each having at least two belt layers consisting of cords and a bead core embedded in each bead portion are mounted on one axle, and a carcass ply is used. The angle of the cord to be formed with respect to the tread circumferential direction is in the range of 75 to 88 °, and each end portion of the carcass is wound from the inside to the outside around the bead core, and each of the winding ends is attached to the inner circumference of the belt layer. The carcass ply cords are located at a lateral position and spaced apart from each other, and at the tire shoulder portion, between the main body portion of the carcass and the winding end portion. At intervals of 0.5 to 5.0 times the diameter, the extending direction of the ply cords of the carcass body portion, which is located between the respective winding ends of the carcass, is defined by the two tires with respect to the circumferential direction of the tread. A pneumatic radial tire combination characterized in that the directions are opposite to each other. 2. In two tires located on the front and rear sides of each side of the vehicle, the extending direction of the ply cords at the respective winding end portions of the carcass is defined by the two tires with respect to the tread circumferential direction. It is characterized in that it is in the opposite direction to
A pneumatic radial tire combination according to claim 1.