JPH02106406A - Pneumatic radial tire - Google Patents

Abstract

PURPOSE:To improve riding comfortableness without damaging high speed durability by composing a multilayered reinforcing part to be burried in a tread rubber in the outer circumference of a carcass, of a plurality of belts having cords extending in a specified direction. CONSTITUTION:A first reinforcing layer composed of a pair of belts 58, 60 is arranged between a carcass 54 layer on a bead section 52 in a tire 50 and a tread 56 disposed on the outer side of the carcass 54. A second reinforcing layer composed of a belt 62 is placed on the outer side of the belt 60 in the first reinforcing layer. A third reinforcing layer composed of a pair of belts 64, 66 is positioned on the outer side of a side section in the width direction of the belt 60. The cord 74 of third reinforcing layer is extended in the circumferential direction. The cross angle (alpha) between a line 70 and the cord 68 of the first reinforcing layer is set larger than the angle (beta) between the line and the cord 72 of the second reinforcing layer.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pneumatic radial tire with enhanced high-speed durability, and in particular, the present invention relates to a pneumatic radial tire that has enhanced high-speed durability, and in particular has a reinforcing portion embedded in the tread rubber on the outer periphery of the carcass and tread. Regarding pneumatic radial tires.

(Prior Art) One of the pneumatic radial tires with improved high-speed durability is a tire 1o shown in FIG. The tire 10 includes a pair of annular beads 12, a carcass 14 placed over the beads, and a tread 16 disposed on the outside of the carcass.
, a pair of first belt layers 18 , 20 located on the outer periphery of the carcass 14 and embedded in the tread rubber, and a second belt layer 22 disposed outside the first belt layer 20 .

As shown in FIG. 2, the belt layer 18 includes a plurality of cords 24 made of steel wire, each cord 24 intersecting an imaginary line 26 extending in the circumferential direction of the tire at an angle of 10 to 40 degrees. The belt layer 18 is arranged on the outside of the carcass 14.

The belt layer 20 includes a plurality of cords 28 made of steel wire, each cord 28 having an imaginary line 26 and a 10-40
intersect at an angle of degrees.

Belt layer 20 has a width dimension smaller than the width dimension of belt layer 18 , and belt layer 20 is disposed outside belt layer 18 such that its cords 28 intersect cords 24 of belt layer 18 .

The second belt layer 22 includes a plurality of cords 30 made of heat-shrinkable organic fiber cords that are long in the circumferential direction of the tire.

This second belt layer 22 is similar to the first belt layer 18.20.
The first belt layer 18.20 has a width dimension greater than the width dimension of the first belt layer 18.
It is arranged outside the belt layer 20 of.

According to the tire 10, since the second belt layer 22 is tightened in a manner similar to that used for barrels, etc., it is effective, so that the tread is tightened when the tire is filled with air or when the vehicle equipped with the tire is running. The so-called lifting that occurs in the tread 16 is prevented by the second belt layer 22 over almost the entire tread 16, and the tread 16 changes from the pre-inflated profile 32 shown in solid lines in FIG. 3 to the post-inflated profile 34 shown in broken lines in FIG. Since the deformation is only slight, high-speed durability can be improved.

However, in the tire IO, the entire outer surface of the first belt layer 18.20 is covered by the second belt layer 22 including a plurality of cords 30 that are long in the circumferential direction of the tire, so that the rigidity of the tire is reduced throughout the tread. becomes larger over time. For this reason, the so-called enveloping property of the tire lO, which envelops the protrusions when riding over them, is reduced.
As a result, there is a problem in that the ride comfort of a vehicle equipped with the tire 10 deteriorates.

Another type of pneumatic radial tire with improved high-speed durability is a tire 40 shown in FIG. Tire 40 includes a pair of second belt layers 42, each having a width dimension smaller than the width dimension of first belt layer 18, 20, in place of second belt layer 22 of tire 10 described above.

As shown in FIG. 5, each of the second belt layers 42 includes a plurality of cords 44 made of heat-shrinkable organic fiber cords that are long in the circumferential direction of the tire, and each of the second belt layers 42 includes The first belt layer except for the center part in the width direction 18.20
The first belt layer 18.2 covers both sides of the belt in the width direction.
It is superimposed on 0.

According to the tire 40, since the second belt layer 42 has an effect, the second belt layer 40 prevents lifting that occurs in a part of the shoulder when filling with air or when a vehicle equipped with the tire 40 is running. , the high-speed durability of the tire can be improved. Moreover, since the widthwise central portion of the first belt layer 20 is not covered by the second belt layer 42, the tire! 0, the rigidity of the tread 16 is smaller than that of the first belt layer 18.2 when riding over a protrusion.
The effect due to the angle change of 0 is large, so the tire 4
0 has excellent envelope properties, and as a result, the ride comfort of a vehicle equipped with the tire 40 is improved.

However, in the tire 40, the effect of the tread 16 by the second belt layer 42 is inferior to that in the tire 10;
Footing that occurs in the tread 16 during air filling or when a vehicle equipped with the tire is running is large, and the center portion of the tread 16 in the width direction tends to protrude. That is, since the expansion of the tread 16 in the outer diameter direction of the tire is larger than that of the shoulder part, the tire 40 changes from the pre-inflation profile 46 shown by the solid line in FIG. 6 to the post-inflation profile shown by the broken line in FIG. Transforms into 48. As a result, the wear resistance of the tire decreases.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a pneumatic radial tire with improved riding comfort and wear resistance without impairing high-speed durability.

(Means for Solving the Problems, Functions and Effects of the Invention) The pneumatic radial tire of the present invention is a pneumatic radial tire comprising a multi-layer reinforcing section located on the outer periphery of the carcass and embedded in the tread rubber. is a first reinforcing layer made up of a plurality of belts each having a plurality of cords that intersect with an imaginary line extending in the circumferential direction of the tire, and each of the belts is attached to the carcass so that the cords intersect with each other. A belt comprising a first reinforcing layer disposed on top of each other on the outside, and a plurality of cords intersecting the imaginary line at an angle smaller than the intersection angle between the imaginary line and the cords of the first reinforcing layer. a second reinforcing layer disposed outside the first reinforcing layer so as not to protrude outward in the width direction of the first reinforcing layer;
They are arranged at intervals in the width direction of the first reinforcing layer on the outside of the first reinforcing layer so as to cover both sides of the first reinforcing layer in the width direction, and are substantially parallel to the imaginary line. and a third reinforcing layer consisting of a pair of belts each having a plurality of arranged cords.

Note that the plurality of cords in the present invention refers to not only a plurality of cords but also the virtual lines and other reinforcing layers of one spirally arranged cord or one folded cord. It includes a plurality of code portions in a predetermined angular relationship to the code.

The cords of the second reinforcing layer intersect with the imaginary line at an angle smaller than the intersection angle between the imaginary line extending in the circumferential direction of the tire and the cords of the first reinforcing layer; Since the layer is arranged so as not to protrude outward in the width direction, lifting of the tread is prevented without increasing the rigidity of the tread due to angle changes. Therefore, the second reinforcing layer contributes to improving riding comfort and wear resistance. On the other hand, since the cords of the third reinforcing layer extend in the circumferential direction of the tire, it contributes to improving the high-speed durability of the tire for the same reason as in the case of the tire 30 described above. Therefore, according to the present invention, high-speed durability is not impaired, and riding comfort and wear resistance are improved.

The intersection angle between the virtual line and the cord of the second reinforcing layer is 5~
The angle is 38 degrees, and the angle is at least 0.5 degrees smaller than the intersection angle between the virtual line and the cord of the first reinforcing layer, and the width dimension of the second reinforcing layer is less than or equal to the stiffness of the first reinforcing layer. It is preferable.

If the intersection angle between the virtual line and the cord of the second reinforcing layer is less than 5 degrees, the rigidity of the tread will increase rapidly, resulting in a sudden decrease in riding comfort. On the other hand, if the intersection angle between the virtual line and the cord of the second reinforcing layer exceeds 38 degrees, the hoop effect decreases rapidly, resulting in a rapid decrease in high-speed durability. Furthermore, the difference between the intersection angle between the imaginary line and the cord of the second reinforcing layer and the intersection angle between the imaginary line and the cord of the first reinforcing layer is less than 0.5 degrees,
The rigidity of the tread increases rapidly, resulting in a rapid decrease in ride comfort. However, when the difference is 0.5 degrees or more, although the moderate effect is maintained,
Since the bending rigidity of the entire second reinforcing layer is reduced, high-speed durability is improved and riding comfort is improved.

It is preferable that the intersection angle between the virtual line and the cord of the third reinforcing layer is 0 to 5 degrees. In this case, the third reinforcing layer has a portion that covers 20 to 70% of the width of the first reinforcing layer and overlaps with the second reinforcing layer.

If the intersection angle between the cord of the third reinforcing layer and the virtual line exceeds 5 degrees, the rigidity of the third reinforcing layer in the tire circumferential direction will be too low, and the effect of preventing lifting will be reduced. Preferably, the intersection angle between the cord of the third reinforcing layer and the virtual line is 0 degrees. If the range of the first reinforcing layer covered by the third reinforcing layer is less than 20%, the effect of preventing lifting is small, and if it exceeds 70%, the third reinforcing layer covers less than 20%.
The stiffness of the entire reinforcing layer becomes too high. In this way, by setting the intersection angle between the cord of the third reinforcing layer and the virtual line and the range of the first reinforcing layer covered by the third reinforcing layer to the above values, high-speed durability is reduced. It is possible to improve ride comfort and wear resistance without causing any damage.

(Example) Referring to FIG. 7, a tire 50 according to the present invention includes a pair of annular beads 52, a carcass 54 hung on the beads, and a tread 56 disposed on the outside of the carcass. A first reinforcing layer consisting of a pair of belts 58 and 60 disposed between the carcass 54 and the tread 56, and a second reinforcing layer consisting of a belt 62 disposed outside the belt 60 of the first reinforcing layer. and a belt 6 of the first reinforcing layer, respectively.
A pair of belts 64.
66.

The carcass 54 was made of 51 polyester fiber cords of 1000 d/2 each with a length of 750 mm.
Consists of two rubberized braais. The cords of the carcass 54 are arranged to form an angle of approximately 90 degrees with an imaginary line extending in the circumferential direction of the tire. Both sides of the carcass 54 in the width direction are folded back around the bead 52. As the cord of the carcass 54, other organic fiber cords such as aromatic polyamide fibers, preferably heat-shrinkable organic fiber cords, may be used, and steel wire may also be used.

Each of the belts 58,60 of the first reinforcing layer is
Cord 68 made of 10.25mm steel wire
It consists of a rubberized braai with 50 pieces/50 mm. As shown in FIG. 8, the belt 58.60 is
The cords 68 intersect an imaginary line 70 extending in the circumferential direction of the tire 50 at an angle α of 20 degrees, and are sequentially arranged on the outside of the carcass 54 so as to be symmetrical with respect to the imaginary line 70. The belt 60 has a width smaller than the width of the belt 58, and the belt 60 has a width smaller than that of the belt 58.
When the belt 58 is superimposed on the outer side of the belt 8, the belt 58 is arranged so as to extend to both sides of the belt 60 in the width direction. The intersection angle α between the cord 68 of the first reinforcing layer and the imaginary line 70 can be selected within the range of 10 to 40 degrees.

7j! The belt 62 of the reinforcing layer of J2 consists of a rubberized braai into which 58 840 d/2 nylon fiber cords 72 are inserted at 50 mm. The belt 62 of the second reinforcing layer has a width smaller than the width of the belt 60 of the first reinforcing layer, as shown in FIG.
2 intersects the imaginary line 70 at an angle β of 15 degrees, which is smaller than the intersection angle α between the imaginary line 70 and the cord 66 of the belt 58, 60 of the first reinforcing layer, and overlaps the belt 60 on the outside thereof, The belt 60 of the first reinforcing layer is arranged so as to extend laterally in the width direction of the belt 62.

Other organic fiber cords such as aromatic polyamide fiber cords can be used as the cords 72 of the belt 62 of the second reinforcing layer. Compared to metal cord, organic fiber cord has
Because it has high adhesion to rubber, it is difficult to peel off even under high temperature and high strain conditions. In addition, the second reinforcing layer 64 is arranged at a position closest to the ground plane compared to other reinforcing layers, and if an organic fiber cord is used as the reinforcing layer cord 72 arranged at such a position, it will improve the road surface. This reduces the impact from the vehicle and improves riding comfort.

The cords 72 of the belt 62 of the second reinforcing layer are preferably heat-shrinkable organic fiber cords, which facilitate the manufacture of the tire.

Intersection angle β between the virtual line 70 and the cord 72 of the second reinforcing layer
can be 5 to 38 degrees and at least 0.5 degrees smaller than the intersection angle α between the virtual line 70 and the cord 68 of the first reinforcing layer.

The width dimension of the belt 62 can be any value smaller than that of the belt 60.

Each of the third reinforcing layer belts 64,66 has an 840
d/2 nylon fiber cord 74, 49 trees, 750 m
Consists of rubberized braai driven in m. belt 64
．． Each of belts 60 .
Belts 5B are placed on the outside of 62 at intervals in the width direction of 60.62. Each of the belts 64, 66 is wound twice so as to double cover an area of 35 mm from the side edge in the width direction to the center in the width direction of the belt 58, 60.

As the cords 74 of each belt of the third reinforcing layer, other organic fiber cords having greater elasticity than metal cords, such as aromatic polyamide fiber cords, preferably heat-shrinkable organic fiber cords can be used. If a cord with low elasticity, such as a metal cord, is used as the cord 74, the tire manufacturing will be complicated due to the low elasticity, and the rigidity of both sides of the third reinforcing layer in the width direction will be lower than the center. As a result, due to the difference in rigidity between both sides and the center, strain during internal pressure filling or strain due to load concentrates at the boundary between both sides and the center, and the boundary parts are damaged.

The intersection angle between the imaginary line 70 and the cord 74 of the third reinforcing layer can be selected within the range of 0 to 5 degrees. The belt of the third reinforcing layer is preferably formed by winding a single cord or a plurality of cords in a spiral manner.

The width dimension of the belt 64.66 of the third reinforcement layer covers a range of 20 to 70% of the width dimension of the belt 1-58.60 of the first reinforcement layer and the width of the belt 62 of the second reinforcement layer. It can be set to a value that overlaps the direction end.

According to the tire 50, the third reinforcing layer belt 64.66
Since the coat 74 extends in the circumferential direction of the tire, when the tire 50 is filled with air or when the vehicle equipped with the tire 50 is running, the tire 50 changes from the contour 76 shown in solid lines in FIG. 9 to the contour 78 shown in broken lines in FIG. This results in only slight deformation, which improves the tire's high-speed durability. Further, the cord 72 of the heald 62 of the second reinforcing layer intersects the imaginary line 70 at an angle β smaller than the intersection angle α between the imaginary line 70 and the coat 66 of the belt 58, 60 of the first reinforcing layer, Furthermore, since the belt 62 of the second reinforcing layer is arranged so as not to protrude from the belt 58, 60 of the first reinforcing layer in the width direction thereof, the rigidity of the tread is small, improving ride comfort and wear resistance. Sexuality is reversed.

(Experimental example) As shown in Table 1, two types of tires A and B based on the present invention were manufactured, and the high-speed durability and riding comfort of these and two conventional tires C and D were compared. and abrasion resistance were compared. The tire size was 205/60R15. For high-speed durability, a drum running tester was used.

Wear resistance was evaluated based on the amount of wear after running for 5,000 m and the appearance of the worn parts. Conventional tire C 100
Table 2 shows the test results using indexes. The larger the value of the index, the greater the improvement effect.

As is clear from Table 2, Tire A of the present invention.

B both improve the drawbacks of conventional tires C and D,
Shows balanced performance.

Table 1 No. table 58° 64° 68° 60: belt of the first reinforcing layer, : second reinforcement layer belt, 66: Third reinforcing layer belt, ? 2,74: Code, :Virtual line.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing a conventional tire, with Figure 1 being a sectional view of the tire, Figure 2 being a diagram for explaining the belt area, and Figure 3 being a diagram showing the outline of the tire. be. Figure 4~
6 is a diagram showing another conventional tire, FIG. 4 is a sectional view of the tire, FIG. 5 is a diagram for explaining the belt area, and FIG. 6 is a diagram showing the outline of the tire. Figures 7 to 9
The figures show one embodiment of the tire of the present invention, in which FIG. 7 is a sectional view of the tire, FIG. 8 is a diagram for explaining the belt area, and FIG. 9 is a diagram showing the outline of the tire. .

Claims (3)

[Claims] (1) In a pneumatic radial tire including a multi-layer reinforcing section located on the outer periphery of the carcass and embedded in the tread rubber, the reinforcing section has a plurality of cords each intersecting with an imaginary line extending in the circumferential direction of the tire. a first reinforcing layer consisting of a plurality of belts, each of which is arranged on the outside of the carcass so that the cords intersect with each other, and the imaginary line A second reinforcing layer comprising a belt having a plurality of cords intersecting the imaginary line at an angle smaller than the intersecting angle with the cords of the first reinforcing layer, the second reinforcing layer extending outward in the width direction of the first reinforcing layer. a second reinforcing layer disposed outside the first reinforcing layer so as not to overhang the first reinforcing layer;
A plurality of reinforcing layers are arranged outside the first reinforcing layer at intervals in the width direction of the first reinforcing layer so as to cover both sides of the reinforcing layer in the width direction, and are arranged substantially parallel to the imaginary line. and a third reinforcing layer consisting of a pair of belts each having a cord. (2) The intersection angle between the imaginary line and the cord of the second reinforcing layer is 5 to 38 degrees, and 0.5 degrees or more than the intersection angle between the imaginary line and the cord of the first reinforcing layer. The pneumatic radial tire according to claim 1, wherein the width of the second reinforcing layer is smaller than that of the first reinforcing layer. (3) The intersection angle between the virtual line and the cord of the third reinforcing layer is 0 to 5 degrees, and the third reinforcing layer has a width of 20 to 70% of the width of the first reinforcing layer. Claim (1) having a portion covering the range and overlapping with the second reinforcing layer.
) pneumatic radial tires.