JP2001287507A - Pneumatic radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic radial tire excellent in maneuvering stability of a vehicle, durability and productivity. SOLUTION: Since a width directional end part of a belt reinforcing layer 30 is positioned in an area of ±20% to the section height H of a radial tire 10 when the tire radial directional outside is a minus (-) area and the tire radial directional inside is a plus (+) area with a maximum width W of a carcass 16 as the center, rigidity of a side part 21 is enhanced, a cornering hose is enlarged, and the maneuvering stability of the vehicle can be improved. Thus, since there is no need to arrange a new reinforcing layer in the side part, the number of part items can be reduced, and the productivity of the radial tire 10 can be improved. Since the belt reinforcing layer 30 is arranged over the side part 21 from a tread part 20, strain of a boundary part between tread rubber 36 and side rubber 38 can be reduced, and as a result of being capable of preventing separation, the durability of the tire 10 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire used for a vehicle, and more particularly, to a pneumatic radial tire capable of improving steering stability, durability and productivity.

[0002]

2. Description of the Related Art As shown in FIG. 6, in a structure of a conventional pneumatic radial tire 100, a belt layer 104 is provided on an outer side of a carcass 102 in a tire radial direction. Further, in order to increase the cornering power by increasing the rigidity of the tread portion, a belt reinforcement layer 108 made of a spirally wound organic fiber material is provided on the outer side of the belt layer 104 in the tire radial direction. I have.

[0003] Although not shown, a reinforcing layer made of steel or organic fiber is separately provided on the side portion of the pneumatic radial tire 100 in order to increase the cornering power and improve the steering stability of the vehicle. Have been.
Such a reinforcing layer is indispensable in order to improve the steering stability of the vehicle. However, if the reinforcing layer is provided separately, the number of components increases, and there is a problem that productivity is reduced.

On the other hand, as shown in FIG. 6, a tread rubber 1 constituting a tread portion of a pneumatic radial tire 100 is provided.
As the generally known rubbers, different types of rubber are used for the side rubbers 06 and the side rubbers 110 constituting the side portions.
That is, the tread portion is required to have abrasion resistance because it is in contact with the road surface, and rubber having better abrasion resistance than the side portions is used. Therefore, separation or the like is likely to occur at the boundary between the tread rubber 106 of the tread portion and the side rubber 110 of the side portion, and there is a problem that the durability of the pneumatic radial tire 100 is reduced.

In order to solve this problem, as shown in FIG. 7, a pneumatic radial tire 101 having a rubber 112 of the same type as the rubber used for the side portion at the widthwise end of the tread portion is considered. Although separation is less likely to occur than in the case of the pneumatic radial tire 100 shown in FIG. 6, it is still difficult to completely eliminate the problem of separation.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic radial tire excellent in steering stability, durability and productivity of a vehicle in consideration of the above fact.

[0007]

In the pneumatic radial tire according to the first aspect, the toroidal carcass straddling between a pair of bead cores provided in the bead portion is disposed radially outside of a toroidal carcass main body. In a pneumatic radial tire having a belt and a belt reinforcing layer arranged on the outer side of the belt in the tire half direction, the widthwise end of the belt reinforcing layer is located near the maximum width of the carcass.

The operation and effect of the pneumatic radial tire according to claim 1 will be described.

Since the widthwise end of the belt reinforcing layer is located in the vicinity of the maximum width of the carcass, the rigidity of the side portion of the pneumatic radial tire is increased and the cornering power is increased to improve the steering stability of the vehicle. can do. For this reason, it is not necessary to separately provide a new reinforcing layer on the side portion to reinforce, so that the number of parts can be reduced,
The productivity of the pneumatic radial tire can be improved.

Further, since the widthwise end of the belt reinforcing layer is located near the maximum width of the carcass, distortion generated at the boundary between the tread rubber layer of the tread portion and the side rubber layer of the side portion can be reduced, and separation can be reduced. It can be prevented as much as possible. As a result, the durability of the pneumatic radial tire can be improved.

In the pneumatic radial tire according to the second aspect, the widthwise end of the belt reinforcing layer has a minus (-) region outside the tire radial direction around the maximum width of the carcass and a plus region inside the tire radial direction. In the case of the (+) region, it is located within a region of ± 20% with respect to the section height of the pneumatic radial tire.

The operation and effect of the pneumatic radial tire according to claim 2 will be described.

The widthwise end of the belt reinforcing layer is minus (-) on the tire radial outside centering on the maximum width of the carcass.
If the area is defined as a plus (+) area in the radial direction of the tire, it is located within an area of ± 20% with respect to the section height of the pneumatic radial tire. Compared with the case of a pneumatic radial tire in which a belt reinforcing layer is provided in a portion, separation can be effectively prevented, and the durability of the pneumatic radial tire can be greatly improved. Further, the durability of the pneumatic radial tire can be improved as compared with a pneumatic radial tire in which the width direction end of the belt reinforcing layer is located in a region of −30%. Furthermore, when compared to a pneumatic radial tire in which the width direction end of the belt reinforcing layer is located in a region of + 30%, the durability of the pneumatic radial tire can be improved, and manufacturing costs and the like can be reduced. be able to.

Further, the pneumatic radial tire of the present invention can increase cornering power as compared with a conventional pneumatic radial tire in which a belt reinforcing layer is provided at a portion facing a tread portion, so that the steering stability of a vehicle can be increased. Performance can be improved. Furthermore, the width direction end of the belt reinforcing layer is ±
Compared with a pneumatic radial tire located in the 30% area, the cornering power can be increased, and the steering stability of the vehicle can be greatly improved.

[0015] In the pneumatic radial tire according to the third aspect, the belt reinforcing layer has at least one layer in which a plurality of cords are arranged substantially parallel to the tire equatorial plane by spirally winding an organic fiber cord. Characterized in that it is a circumferential reinforcing layer made of

The operation and effect of the pneumatic radial tire according to claim 3 will be described.

The belt reinforcing layer is a circumferential reinforcing layer composed of at least one layer in which a plurality of cords are arranged substantially parallel to the tire equatorial plane by winding an organic fiber cord in a spiral shape. Directional tensile stiffness can be increased. As a result, the high-speed durability of the pneumatic radial tire can be improved.

[0018] In the pneumatic radial tire according to the fourth aspect, the belt is preferably constituted by an inclined belt layer composed of at least one layer in which cords extending inclining with respect to the tire equatorial plane are arranged.

In the pneumatic radial tire according to the fifth aspect, the belt includes at least one inclined belt layer in which cords extending inclining with respect to the tire equatorial plane are arranged, and a radially outer side of the inclined belt layer. And a circumferential belt layer comprising at least one layer in which a plurality of cords are arranged substantially parallel to the tire equatorial plane.

The operation and effect of the pneumatic radial tire according to claim 5 will be described.

The belt is composed of at least one inclined belt layer in which cords extending inclining with respect to the tire equatorial plane are arranged, and the belt is disposed radially outward of the inclined belt layer and substantially parallel to the tire equatorial plane. And a circumferential belt layer composed of at least one layer in which a plurality of cords are arranged, for example, an inclined belt layer composed of at least one layer in which cords extending inclining with respect to the tire equatorial plane are arranged. The tensile rigidity in the tire circumferential direction can be increased as compared with the case where the configured belt layer is used. For this reason, the high-speed durability of the pneumatic radial tire can be improved.

In the pneumatic radial tire according to the present invention, the belt has a first inclined belt layer comprising at least one layer in which a first cord extending inclining with respect to the tire equatorial plane is arranged; A second inclined belt layer comprising at least one layer in which a second cord that is inclined to the side opposite to the inclination direction of the first cord with respect to the surface and intersects the first cord is arranged. Features.

The operation and effect of the pneumatic radial tire according to claim 6 will be described.

The belt has a first inclined belt layer composed of at least one layer in which first cords extending inclining with respect to the tire equatorial plane are arranged, and the inclination direction of the first cord with respect to the tire equatorial plane. A second layer consisting of at least one layer in which a second code inclined to the opposite side and intersecting the first code is arranged;
As compared with the case of the belt layer composed of the inclined belt layer consisting of one layer in which cords extending inclining with respect to the tire equatorial plane are arranged,
The tensile rigidity of the pneumatic radial tire can be increased.

[0025] In the pneumatic radial tire according to claim 7, the elastic modulus of the organic fiber cord of the belt reinforcing layer is 2.9.
kN / mm ² or more.

The operation and effect of the pneumatic radial tire according to claim 7 will be described.

By setting the elastic modulus of the organic fiber cord of the belt reinforcing layer to 2.9 kN / mm ² or more, the tensile rigidity of the belt reinforcing layer can be increased.

The number of organic fiber cords to be driven is 3
It is preferably 5 to 70 pieces / 50 mm.

[0029]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a pneumatic radial tire according to an embodiment of the present invention.
It is abbreviated as "radial tire" as appropriate. ) Will be described.

As shown in FIG. 1, a radial tire 10
Is a carcass 16 that is folded back from the inside of the tire to the outside around the bead core 14 embedded in the bead portion 12 and locked.
A bead filler 18 disposed between the main body 16 </ b> A and the winding portion 16 </ b> B of the carcass 16, a tread portion 20 located at the crown of the carcass 16, a side portion 21 located outside the carcass 14, A belt reinforcing layer 30 is provided inside the portion 20, and two belt layers 24 are provided further inside the tire reinforcing layer 30. At the end of the tread rubber 36 of the tread portion 20 in the tire width direction, a rubber 39 of the same type as the side rubber 38 of the side portion 21 is provided.

The carcass 16 has fiber cords arranged in a direction substantially perpendicular to the circumferential direction. In the present embodiment, the carcass 16 is composed of two radial carcass plies.

As shown in FIG. 4, the belt layer 24 has a single inclined belt layer 2 in which a plurality of steel cords 26 (cords) extending at an angle to the tire equatorial plane CL are arranged.
4A and a single circumferential belt layer 24 having a plurality of organic fiber cords 28 (cords) arranged on the inclined belt layer 24A and substantially parallel to the tire equatorial plane CL.
B.

Here, the inclination angle of the steel cord 26 of the inclined belt layer 24A with respect to the tire equatorial plane CL is 15 °.
It is preferable that the angle be in the range of 45 °.

On the other hand, the circumferential belt layer 24B comprises a rubberized narrow strip including a plurality of organic fiber cords 28, the organic fiber cords 28 being substantially parallel to the tire circumferential direction (0 ° to 5 °). It is wound in a spiral shape (spiral shape).

Incidentally, a steel cord can be used for the circumferential belt layer 24B instead of the organic fiber cord 28.

Next, the belt reinforcing layer 30 located outside the belt layer 24 in the tire radial direction will be described.

The belt reinforcing layer 30 is formed of a rubberized narrow strip including a plurality of organic fiber cords (not shown).
° to 5 °) in a helical (spiral) shape.

The widthwise end of the belt reinforcing layer 30 is defined as a minus (-) region outside the tire radial direction with respect to the point P where the carcass 16 has the maximum width W, and a plus (+) region inside the tire radial direction. ), It is located at a position ± 0% with respect to the section height H of the radial tire 10, that is, at a point P where the maximum width W of the carcass 16 is obtained. In other words, the belt reinforcing layer 30 is
To the side portion 21.

The elastic modulus of the organic fiber cord forming the belt reinforcing layer 30 is preferably 2.9 to 17.0 kN / mm ² .

In this embodiment, the belt layer 24 is
Although the form constituted by the inclined belt layer 24A and the circumferential belt layer 24B has been described, the present invention is not limited to this, and only one inclined belt layer 24 may be used.

As shown in FIG. 5, instead of the circumferential belt layer 24B, a plurality of slant belt layers 24A extending in a direction opposite to the direction in which the steel cords 26 are inclined with respect to the tire equatorial plane CL. At least one inclined belt layer 24C in which the steel cords 34 (or organic fiber cords) are arranged may be used.

Next, the operation and effect of the pneumatic radial tire 10 of the present embodiment will be described.

Since the widthwise end of the belt reinforcing layer 30 used for the radial tire 10 is located at the maximum width W of the carcass 16, the belt reinforcing layer is provided only at a portion opposed to the tread portion as in the related art. The rigidity of the side portion 21 of the radial tire 10 can be increased and the cornering power can be increased as compared with a pneumatic radial tire that is in use. As a result, the steering stability can be improved without using an insert, a flipper or the like particularly around the bead core.

In addition, since it is not necessary to provide a new reinforcing layer on the side portion 21 to reinforce, the number of parts can be reduced.
The productivity of the radial tire 10 can be improved.

Further, the belt reinforcing layer 30 is
Since it is provided from 0 to the side portion 21, distortion generated near the boundary between the tread rubber 36 of the tread portion 20 and the side rubber 38 of the side portion 21 can be reduced. As a result, separation at the boundary can be prevented as much as possible, and the durability of the radial tire 10 can be improved.

The belt reinforcing layer 30 of the pneumatic radial tire 10 of the present embodiment is formed of at least one layer in which a plurality of cords are spirally wound and arranged substantially parallel to the tire equatorial plane CL. Because it is a circumferential reinforcing layer,
The tensile rigidity in the tire circumferential direction can be increased. As a result, the high-speed durability of the pneumatic radial tire 10 can be improved.

Further, by setting the elastic modulus of the organic fiber cord of the belt reinforcing layer 30 in the range of 2.9 to 17.0 kN / mm ² , the tensile strength of the belt reinforcing layer 30 can be increased. Conversely, the elastic modulus of the organic fiber cord is 2.9k
If it is less than N / mm ² , sufficient tensile rigidity cannot be obtained, which is inappropriate.

In particular, when the belt layer 24 of the pneumatic radial tire 10 of the present embodiment is constituted by the inclined belt 24A and the circumferential belt 24B, for example, when the belt layer 24 is constituted by the inclined belt layer 24A and the inclined belt 24C. Alternatively, as compared with the case where only the inclined belt layer 24A is used, the tensile rigidity in the tire circumferential direction can be increased, and the high-speed durability of the pneumatic radial tire 10 can be improved.

In the above embodiment, the tire reinforcing layer 3
Although the embodiment in which the widthwise end of the zero is located at the point P has been described, the present invention is not limited to this. ± 20% of the section height H of the pneumatic radial tire 10 when the radial outside is defined as a minus (−) region and the tire radial inside is defined as a plus (+) region.
It suffices if it is located within the area of.

For example, as shown in FIG. 2, the widthwise end of the belt reinforcing layer 32 is minus (-) at the point P (0% position) where the maximum width W of the carcass 16 is the center and at the tire radial outside. ) Area, plus (+) inside the tire radial direction
In the case of the region, it may be located at + 20% with respect to the section height H of the radial tire 50.

Further, as shown in FIG.
2 may be located at -20% in the width direction.

(Test Example) As the pneumatic radial tire of the present invention, the radial tire 10 (Example 1) of the first embodiment, the radial tire 50 (Example 2) of the second embodiment, and the radial tire of the third embodiment Tire 60 (Example 3)
As shown in Table 1 below, these radial tires 10, 50, 60 and the tread portion 106 shown in FIG.
Radial tire 100 in which the tire reinforcing layer 108 is provided only on the tire (conventional product), and the width direction end of the belt reinforcing layer is -30.
% And a radial tire (Comparative Example 2) in which the width direction end of the belt reinforcing layer is located in a region of + 30% (Test Example 1).

In Table 1 below, the belt reinforcing layer end type “A” means a type in which the tire reinforcing layer is provided at a portion facing the tread portion, and is different from the belt reinforcing layer end type “B”. Means a type in which the belt reinforcing layer is provided from the tread portion to the side portion.

[0054]

[Table 1]

In this test, a pneumatic radial tire having a size of 205 / 65R15 was used, and a rim size: 15 ×
6.5JJ, load: 4.70kN, internal pressure: 200kP
a, Speed: Performed by a cornering power measurement tester under the conditions of 30 km / h.

The results of Test Example 1 were as shown in Table 2 below. Note that the test results are expressed in an index notation with the cornering power of the conventional product set to 100, and indicate that the larger the numerical value, the larger the cornering power.

[0057]

[Table 2]

As shown in Table 2 above, the cornering power of the radial tires of Examples 1 to 3 of the present invention was larger than that of the conventional radial tire. Also, in comparison with the cornering power of the radial tires of Comparative Examples 1 and 2, Example 1
The cornering powers of the radial tires Nos. 1 to 3 were almost the same or further increased.

As a result, the radial tire 10 of the present invention,
It was confirmed that the steering stability of 50 and 60 was improved.

Next, a durability measurement test (Test Example 2) of the pneumatic radial tire of the present invention will be described. The same kind as in Test Example 1 was used as a prototype in this test.

In this test, a pneumatic radial tire having a size of 205 / 65R15 was used, and a rim size: 15 ×
6.5JJ, load: 7.84kN, internal pressure: 300kP
a, Speed: Performed by a durability tester under the conditions of 50 km / h.

The results of Test Example 2 were as shown in Table 3 below. The test results are expressed as an index with the durability of the conventional product (running distance until separation occurs at the boundary between the side rubber layer and the tread rubber layer) as 100. This indicates that the durability is improved.

[0063]

[Table 3]

As shown in Table 3, it was confirmed that the durability of the radial tires of Examples 1 to 3 of the present invention was improved as compared with the conventional radial tire.

Further, even when compared with Comparative Examples 1 and 2, it was confirmed that the durability of the radial tires of Examples 1 to 3 of the present invention was improved.

Further, in Comparative Example 1, the cornering power is increased and the steering stability is improved as compared with the conventional product, but the durability is reduced and disadvantageous, whereas in Comparative Example 2, the cornering power and the durability are improved as compared with the conventional product. Both rise, but cost such as material cost becomes a problem, which is inconvenient.

[0067]

According to the pneumatic radial tire of the present invention, since the belt reinforcing layer is continuously wound to the vicinity of the maximum width of the carcass, the rigidity of the side portion is increased and the cornering power can be improved. In particular, the steering stability can be improved without using an insert, a flipper or the like around the bead core.

Further, the separation occurring at the boundary between the tread rubber of the tread portion and the side rubber of the side portion can be reduced, and the durability of the pneumatic radial tire can be improved.

Further, since it is not necessary to separately provide a new reinforcing layer on the side portion, the number of members and the number of assembling steps can be reduced, and the productivity of the pneumatic radial tire can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a pneumatic radial tire according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a pneumatic radial tire according to another embodiment of the present invention.

FIG. 3 is a partial sectional view of a pneumatic radial tire according to another embodiment of the present invention.

FIG. 4 is a plan view of a belt layer of the pneumatic radial tire of the present invention.

FIG. 5 is a plan view of a belt layer of a pneumatic radial tire according to another example.

FIG. 6 is a partial sectional view of a conventional pneumatic radial tire.

FIG. 7 is a partial sectional view of a conventional pneumatic radial tire.

[Explanation of symbols]

Reference Signs List 10 radial tire (pneumatic radial tire) 12 bead portion 14 bead core 16 carcass 24 belt layer (belt) 24A inclined belt layer, first inclined belt layer 24B circumferential belt layer 24C second inclined belt layer 30 belt reinforcing layer

Claims (7)

[Claims] 1. A belt disposed radially outside a body portion of a carcass forming a toroid over a pair of bead cores provided on a bead portion, and a belt disposed outside the belt in a tire half direction. A pneumatic radial tire having a reinforcing layer, wherein a width direction end of the belt reinforcing layer is located near a maximum width of a carcass. 2. The end of the belt reinforcing layer in the width direction has a minus (-) region outside the tire radial direction and a plus (+) region inside the tire radial direction around the maximum width of the carcass. The pneumatic radial tire according to claim 1, wherein the pneumatic radial tire is located within a range of ± 20% with respect to a section height of the pneumatic radial tire. 3. The belt reinforcing layer is a circumferential reinforcing layer composed of at least one layer in which a plurality of cords are arranged substantially parallel to the tire equatorial plane by winding an organic fiber cord spirally. The pneumatic radial tire according to claim 1 or 2, wherein: 4. The belt according to claim 1, wherein the belt is constituted by at least one inclined belt layer in which cords extending obliquely with respect to the tire equatorial plane are arranged. The pneumatic radial tire according to 1. 5. The belt according to claim 1, wherein the belt has at least one layer of cords extending in a direction inclined with respect to the tire equatorial plane, and a belt disposed radially outside the inclined belt layer with respect to the tire equatorial plane. The pneumatic radial tire according to any one of claims 1 to 3, comprising: a circumferential belt layer including at least one layer in which a plurality of cords are arranged substantially in parallel. 6. A belt according to claim 1, wherein said belt has at least one layer of a first cord arranged to extend obliquely to the tire equatorial plane, and said first cord to the tire equatorial plane. And a second inclined belt layer comprising at least one layer in which a second cord that is inclined in a direction opposite to the inclination direction and intersects with the first cord is arranged. 4. The pneumatic radial tire according to any one of 3. 7. The pneumatic radial tire according to claim 1, wherein the elastic modulus of the organic fiber cord of the belt reinforcing layer is 2.9 kN / mm ² or more.