JP5187009B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

In recent years, in some vehicle types, it is required to increase the side rigidity of pneumatic tires in order to cope with higher engine output.
In that case, in order to improve the side rigidity of a pneumatic tire, enlarging a bead filler etc. can be considered (patent document 1).
JP 2000-313205 A

However, when the size of the bead filler is increased, there is a problem that heat dissipation at the bead portion is reduced as the volume of the bead filler is increased, and the durability of the tire is reduced due to heat storage.
An object of the present invention is to provide a pneumatic tire that ensures heat dissipation of a bead portion and does not cause deterioration in durability even when side rigidity is increased.

In order to achieve the above object, the present invention provides an annular bead core embedded in a pair of left and right bead portions, a bead filler positioned on the outer periphery thereof, and a tread portion extending from the tread portion to the pair of left and right bead portions. A pneumatic tire comprising the bead core and a carcass material folded back on the bead filler from the inside in the tire width direction to the outside through the inside in the tire radial direction, and having a width along the tire radial direction in the sidewall portion And a high thermal conductivity layer that extends in the tire circumferential direction and has a portion in the tire radial direction in contact with the bead filler is provided, and the high thermal conductivity layer has a higher heat than the sidewall rubber provided in the sidewall portion. have a conductivity, part of the high thermal conductivity layer in contact with the bead filler, the bead filler in the tire width direction And it is located in the part.

  According to the pneumatic tire of the present invention, heat generated in the bead portion is radiated from the sidewall portion through the high thermal conductivity layer, so that heat accumulation in the bead portion can be suppressed, thereby suppressing rubber deterioration. In addition, the durability of the pneumatic tire can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view of the pneumatic tire according to the first embodiment.
The pneumatic tire 10 according to the first embodiment includes a carcass layer 12 forming a skeleton on the tire inner side, an annular bead core 16 embedded in a pair of left and right bead portions 14 and wrapped around a folded portion of the carcass layer 12, and an outer periphery thereof. A bead filler 18 located in the belt, a belt layer 22 attached to the outside of the carcass layer 12 in the tread portion 20, and the like.
Further, the pneumatic tire 10 includes a tuber rubber 20 provided in the bead part 14, a side wall rubber 26 provided in the side wall part 24, a shoulder rubber 30 provided in the shoulder part 28, and a tread rubber 32 provided in the tread part 20. The inner liner 34 made of non-breathable rubber provided on the inner side of the carcass layer 12 is included.

The pneumatic tire 10 includes a high thermal conductivity layer 40.
The high thermal conductivity layer 40 has a width along the tire radial direction in the sidewall portion 24 and extends in the tire circumferential direction.
And the location inside the tire radial direction of the high thermal conductivity layer 40 is in contact with the bead filler 18.
The high thermal conductivity layer 40 has a higher thermal conductivity than the sidewall rubber 26 provided in the sidewall portion 24.
In the present embodiment, the portion on the outer side in the tire radial direction of the high thermal conductivity layer 40 extends to the shoulder portion 28, and more specifically, extends to the shoulder portion 28 in the vicinity of the tread portion 20. The high thermal conductivity layer 40 has a higher thermal conductivity than the sidewall rubber 26 and the shoulder rubber 30.

The high thermal conductivity layer 40 will be described in more detail.
The high thermal conductivity layer 40 includes, for example, an inner layer 42 and an outer layer 44.
The inner layer 42 has a width along the tire radial direction in the sidewall portion 24 and extends in the tire circumferential direction, and a portion on the inner side in the tire radial direction is in contact with the bead filler 18. In the present embodiment, the inner layer 42 has a width along the tire radial direction in the sidewall portion 24 and the shoulder portion 28, extends in the tire circumferential direction, and a portion on the inner side in the tire radial direction contacts the bead filler 18. doing.
The outer layer 44 is positioned outside the inner layer 42 in the tire width direction in the sidewall portion 24, has a width along the tire radial direction, and extends in the tire circumferential direction. In the present embodiment, the outer layer 44 is located outside the inner layer 42 in the tire width direction in the sidewall portion 24 and the shoulder portion 28 and has a width along the tire radial direction and extends in the tire circumferential direction. doing.
The inner layer 42 and the outer layer 44 are connected at one end of both ends in the width direction, and the remaining portion of the inner layer 42 and the remaining portion of the outer layer 44 excluding this one end are separated in the tire width direction. Are arranged. In the present embodiment, the inner layer 42 and the outer layer 44 are connected at one end in the width direction located outside in the tire radial direction, and the remaining portion of the inner layer 42 and the remaining portion of the outer layer 44 excluding this one end are connected. The portions are spaced apart in the tire width direction.

In the present embodiment, the inner layer 42 and the outer layer 44 are formed of separate members, but the inner layer 42 and the outer layer 44 may be formed of a single member.
Further, the inner layer 42 and the outer layer 44 have higher thermal conductivity than the sidewall rubber 26 and the shoulder rubber 30.

  By providing such a high thermal conductivity layer 40, heat generated in the bead portion 14 is conducted to the sidewall portion 24 (or the sidewall portion 24 and the shoulder portion 28), and the sidewall portion 24 (or the sidewall portion 24). And from the surface of the shoulder portion 28) to the outside of the tire efficiently, it is possible to suppress the accumulation of heat in the bead portion, thereby suppressing rubber deterioration in the bead portion and improving the durability of the pneumatic tire. it can.

In the high thermal conductivity layer 40, for example, as shown in FIG. 2, a plurality of cords 50 having high thermal conductivity are embedded in parallel in a belt-like coat rubber 48 having high thermal conductivity. It can be comprised from viscous bodies, such as the cord layer 52, the rubber composition which has high heat conductivity, or a sealant material.
As the cord 50 constituting the cord layer 52, a metal cord such as steel or copper can be used.
The use of a metal cord layer using such a metal cord as the cord layer 22 is desirable because it has a very high thermal conductivity and can improve the damage resistance of the tire. Is desirable.
Examples of the rubber composition having thermal conductivity include a rubber composition having a high carbon black content and a rubber composition containing metal powder or carbon fiber.

Further, the cord 50 extends in a direction intersecting the tire circumferential direction, and heat generated in the bead portion 14 is conducted to the sidewall portion 24 (or the sidewall portion 24 and the shoulder portion 28). It is configured as follows.
In this case, if the cord 50 extends at an angle within a range of 90 ± 45 degrees with respect to the tire circumferential direction, the heat conduction distance in the tire radial direction is shortened, which is advantageous in terms of heat dissipation. It becomes.

  As the metal cord constituting the metal cord layer, it is desirable to use a single wire rather than a stranded wire in order to minimize the change in rigidity of the tire. Further, in order to prevent the heat transfer effect of the metal cord layer from becoming insufficient, the number of ends of the metal cord (number of cords to be driven) and the wire diameter are set to 10 pieces / 50 mm or more and 0.05 mm or more, respectively, and the rigidity of the tire is increased. In order not to increase the ride comfort, the distance is desirably 30 pieces / 50 mm or less and 0.15 mm or less, respectively.

  The surface of the sidewall portion 24 (or the sidewall portion 24 and the shoulder portion 28) in the region where the high thermal conductivity layer 40 is disposed may be smooth like a general tire, but dimples are formed on the surface. It is desirable that the surface be wavy. By doing in this way, since the surface area of the side wall part 24 (or the side wall part 24 and the shoulder part 28) is ensured large, the heat dissipation to the exterior of the tire of the heat conducted by the high thermal conductivity layer 40 is improved. be able to.

In the present embodiment, the inner-layer layer 42 has a portion on the inner side in the tire radial direction between the bead filler 18 located on the inner side in the tire width direction and the carcass layer 12 facing the bead filler 18. The portion of the inner layer 42 thus sandwiched is a portion that contacts the bead filler 18.
When conducting the heat of the bead filler 18 to the outside of the bead filler 18, it is desirable that the portion of the inner layer 42 that contacts the bead filler 18 has a width of 10 mm or more in the tire radial direction. This is because if the amount of wrap between the inner layer 42 and the bead filler 18 is less than 10 mm, the heat of the bead filler 18 is not easily transmitted, and the inner layer 42 is easily peeled off from the bead filler 18.
Extending the inner radial end of the inner layer 42 to the vicinity of the bead core 16 is desirable for efficiently conducting the heat of the bead filler 18 and improving the durability of the tire.
Note that the end portion of the inner layer 42 on the inner side in the tire radial direction may be folded together with the carcass layer 12 so as to wrap the bead portion 14.

The inner and outer ends of the high thermal conductivity layer 40 in the tire radial direction, that is, the inner and outer ends of the inner layer 42 and the outer layer 44 in the tire radial direction are from the tire maximum width position 46 to the tire diameter. It is located within a range of 10 mm or more away inward and outward in the direction.
This is because when both ends of the inner layer 42 and the outer layer 44 in the tire radial direction are located within a range of less than 10 mm from the tire maximum width position 46 inward and outward in the tire radial direction, This is because the inner layer 42 and the outer layer 44 are easy to peel off due to the approach.

Further, in order to efficiently release heat from the surface of the sidewall portion 24 to the outside of the tire, the high thermal conductivity layer 40 is located on the surface of the sidewall portion 24 in the sidewall portion 24 or the surface of the sidewall portion 24. To 3 mm. That is, the outer layer 44 is exposed on the surface of the sidewall portion 24 and the shoulder portion 28 in the sidewall portion 24 and the shoulder portion 28, or is located within a range of 3 mm from the surface of the sidewall portion 24 and the shoulder portion 28. In addition, heat is efficiently released from the surfaces of the sidewall portion 24 and the shoulder portion 28 to the outside of the tire.
In the case where the high thermal conductivity layer 40 is formed of a metal cord layer, it is located on the inside of the surface of the sidewall portion 24 without being exposed on the surface of the sidewall portion 24 from the viewpoint of preventing the generation of rust. It is preferable.

A tire of 225 / 45ZR18 93Y is incorporated into a rim of 18 × 71 / 2JJ, the air pressure is set to 220 kPa, the load durability and the damage resistance are compared with those of the conventional products and Examples 1 to 7, and the comparison results are shown in FIG.
(Conventional product)
This is a conventional pneumatic tire that does not have the high thermal conductivity layer 40 composed of the inner layer 42 and the outer layer 44.

Example 1
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 30 degrees with respect to the tire circumferential direction.
The width of the portion of the inner layer 42 that contacts the bead filler 18 along the tire radial direction, that is, the wrap amount of the inner layer 42 that contacts the bead filler 18 is 10 mm.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 20 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 2 mm from the surface of the sidewall portion 24. Is located.
(Example 2)
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 30 degrees with respect to the tire circumferential direction.
The width along the tire radial direction of the portion of the inner layer 42 that contacts the bead filler 18, that is, the wrap amount of the inner layer 42 that contacts the bead filler 18 is 20 mm.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 20 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 2 mm from the surface of the sidewall portion 24. Is located.

(Example 3)
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 30 degrees with respect to the tire circumferential direction.
The width along the tire radial direction of the portion of the inner layer 42 that contacts the bead filler 18, that is, the wrap amount of the inner layer 42 that contacts the bead filler 18 is 20 mm.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 10 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 2 mm from the surface of the sidewall portion 24. Is located.
Example 4
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 30 degrees with respect to the tire circumferential direction.
The width along the tire radial direction of the portion of the inner layer 42 that contacts the bead filler 18, that is, the wrap amount of the inner layer 42 that contacts the bead filler 18 is 20 mm.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 20 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 3 mm from the surface of the sidewall portion 24. Is located.

(Example 5)
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 60 degrees with respect to the tire circumferential direction.
The width along the tire radial direction of the portion of the inner layer 42 that contacts the bead filler 18, that is, the wrap amount of the inner layer 42 that contacts the bead filler 18 is 20 mm.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 20 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 2 mm from the surface of the sidewall portion 24. Is located.
(Example 6)
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 30 degrees with respect to the tire circumferential direction.
The width along the tire radial direction of the portion of the inner layer 42 in contact with the bead filler 18, that is, the wrap amount of the inner layer 42 in contact with the bead filler 18 is the same value as the dimension along the tire radial direction of the bead filler 18. It is.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 20 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 2 mm from the surface of the sidewall portion 24. Is located.
(Example 7)
This is a pneumatic tire having a high thermal conductivity layer 40 composed of an inner layer 42 and an outer layer 44.
The high thermal conductivity layer 40 is a steel cord layer made of a plurality of steel cords and coat rubber covering them, and the steel cords extend in a direction having an angle of 30 degrees with respect to the tire circumferential direction.
The width along the tire radial direction of the portion of the inner layer 42 in contact with the bead filler 18, that is, the wrap amount of the inner layer 42 in contact with the bead filler 18 is the same value as the dimension along the tire radial direction of the bead filler 18. It is.
The outer ends in the tire radial direction of the inner layer 42 and the outer layer 44 are located at a location 20 mm from the tire maximum width position to the outer side in the tire radial direction, and the outer layer 44 is a location 2 mm from the surface of the sidewall portion 24. Is located.
The surface of the sidewall portion 24 in the region where the outer layer 44 is disposed is formed in a wave shape, and a large surface area is secured.

[Load durability]
Using a drum tester, the load was increased every two hours, and the load when the tire failed was compared.
[Trauma resistance]
We entered a curb with a height of 50 mm at an angle of 10 °, and increased the speed each time the number was increased, and compared the speed until the tire broke down.
The evaluation is indicated by an index with the measured value of the conventional product as 100, and the larger the index value, the better the load durability and the damage resistance.
From FIG. 3, it can be seen that the pneumatic tires (Examples 1 to 7) of the present invention are superior in load durability and damage resistance compared to conventional products.

Next, second to seventh embodiments will be described. In the following embodiments, the same portions and members as those in the first embodiment are denoted by the same reference numerals, and only the portions different from the first embodiment will be described.
(Second Embodiment)
FIG. 4 is a cross-sectional view of the pneumatic tire of the second embodiment.
In the pneumatic tire 10 of the second embodiment, the portion of the high thermal conductivity layer 40 that contacts the bead filler 18, that is, the portion of the inner layer 42 that contacts the bead filler 18 extends to the bead core 16. This is different from the first embodiment.

(Third embodiment)
FIG. 5 is a cross-sectional view of the pneumatic tire of the third embodiment.
In the pneumatic tire 10 of the third embodiment, the portion of the high thermal conductivity layer 40 that contacts the bead filler 18, that is, the portion of the inner layer 42 that contacts the bead filler 18 is the bead filler 18 in the tire width direction. The point located inside differs from 1st Embodiment.

(Fourth embodiment)
FIG. 6 is a cross-sectional view of the pneumatic tire of the fourth embodiment.
In the pneumatic tire 10 of the fourth embodiment, the portion of the high thermal conductivity layer 40 that contacts the bead filler 18, that is, the portion of the inner layer 42 that contacts the bead filler 18 is the bead filler 18 in the tire width direction. The point located in the inside and the point extended to the bead core 16 differ from 1st Embodiment.

(Fifth embodiment)
FIG. 7 is a cross-sectional view of the pneumatic tire of the fifth embodiment.
In the pneumatic tire 10 of the fifth embodiment, the portion of the high thermal conductivity layer 40 that contacts the bead filler 18, that is, the portion of the inner layer 42 that contacts the bead filler 18 is located outside in the tire width direction. The point which is pinched | interposed between the location of the bead filler 18 and the carcass layer 12 which faces the location of this bead filler 18 differs from 1st Embodiment.

(Sixth embodiment)
FIG. 8 is a cross-sectional view of the pneumatic tire of the sixth embodiment.
In the pneumatic tire 10 of the sixth embodiment, the high thermal conductivity layer 40 is formed of a single member, that is, the inner layer 42 and the outer layer 44 are formed of a single member. However, this is different from the first embodiment.

(Seventh embodiment)
FIG. 9 is a cross-sectional view of the pneumatic tire of the seventh embodiment.
In the pneumatic tire 10 of the seventh embodiment, the inner layer 42 and the outer layer 44 constituting the high thermal conductivity layer 40 are connected to one end in the width direction located on the inner side in the tire radial direction. The remaining portion of the inner layer 42 and the remaining portion of the outer layer 44 are different from those of the first embodiment in that they are spaced apart in the tire width direction.

The effects similar to those of the first embodiment can be obtained by the second to seventh embodiments.
In the description of the embodiment, the case where the high thermal conductivity layer 40 includes the inner layer 42 and the outer layer 44 has been described. However, the configuration of the high thermal conductivity layer 40 is arbitrary. In short, it is sufficient that the heat generated in the bead portion 14 is dissipated from the sidewall portion 24 through the high thermal conductivity layer 40. For this purpose, the high thermal conductivity layer 40 is formed on the tire in the sidewall portion 24. A sidewall provided in the sidewall portion 24, having a width along the radial direction, extending in the tire circumferential direction, and a portion on the inner side in the tire radial direction of the high thermal conductivity layer 40 is in contact with the bead filler 18. What is necessary is just to have a heat conductivity higher than the rubber | gum 26. FIG.

1 is a half sectional view of a pneumatic radial tire according to a first embodiment of the present invention. It is sectional drawing of a high heat conductivity layer. It is a figure which shows the result of having compared the conventional goods and Examples 1 thru | or 7 regarding load durability and damage resistance. It is a half sectional view of a pneumatic radial tire according to a second embodiment of the present invention. FIG. 6 is a half sectional view of a pneumatic radial tire according to a third embodiment of the present invention. It is a half sectional view of a pneumatic radial tire according to a fourth embodiment of the present invention. It is a half sectional view of a pneumatic radial tire according to a fifth embodiment of the present invention. It is a half sectional view of a pneumatic radial tire according to a sixth embodiment of the present invention. It is a half sectional view of a pneumatic radial tire according to a seventh embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Pneumatic tire, 14 ... Bead part, 16 ... Bead core, 18 ... Bead filler, 24 ... Side wall part, 28 ... Shoulder part, 40 ... High thermal conductivity layer, 42 ... Inner layer, 44. Outer layer.

Claims (13)

An annular bead core embedded in a pair of left and right bead portions and a bead filler located on the outer periphery thereof ;
A carcass material extending from the tread portion to the pair of left and right bead portions and passing through the inside of the bead core in the tire radial direction from the inside to the outside in the tire width direction, and folded back onto the bead core and the bead filler;
A pneumatic tire with
The sidewall portion has a width along the tire radial direction and is provided with a high thermal conductivity layer that extends in the tire circumferential direction and the inner portion in the tire radial direction contacts the bead filler.
The high thermal conductivity layer have a higher thermal conductivity than the side wall rubber is provided on the side wall portion,
The portion of the high thermal conductivity layer that contacts the bead filler is located inside the bead filler in the tire width direction.
A pneumatic tire characterized by that. The high thermal conductivity layer has a width along the tire radial direction in the sidewall portion, extends in the tire circumferential direction, and an inner layer in which the inner portion in the tire radial direction contacts the bead filler, and in the sidewall portion, An outer layer positioned outside the inner layer in the tire width direction and having a width along the tire radial direction and extending in the tire circumferential direction,
The inner layer and the outer layer are connected at one end of both ends in the width direction, and the remaining portion of the inner layer and the remaining portion of the outer layer excluding the one end are separated in the tire width direction. Arranged,
The pneumatic tire according to claim 1. The portion of the high thermal conductivity layer in contact with the bead filler has a dimension of 10 mm or more in the tire radial direction.
The pneumatic tire according to claim 1 or 2 , characterized in that. End of the tire radially inwardly and outwardly of the high thermal conductivity layer, in claim 1 to 3 are located within a distance 10mm or more outwardly in the lateral and radial direction of the tire from the tire maximum width position The pneumatic tire according to any one of the preceding claims. In the high thermal conductivity layer is the sidewall portion, the located on the surface of the sidewall portion, or any one to claims 1 to 4 is located within the range of 3mm from the surface of the side wall portions The described pneumatic tire. The pneumatic tire according to any one of claims 1 to 5 , wherein a plurality of dimples are formed in a surface portion of the sidewall portion in which the high thermal conductivity layer is embedded. The pneumatic tire according to any one of claims 1 to 5 , wherein a surface portion of the sidewall portion in which the high thermal conductivity layer is embedded is formed in a wave shape. The high thermal conductivity layer is a metal cord layer comprising a plurality of metal cords and a coat rubber covering the metal cords.
The pneumatic tire according to any one of claims 1 to 7 , characterized in that The metal cord extends in a direction intersecting the tire circumferential direction,
The pneumatic tire according to claim 8 . The metal cord is a steel cord;
The pneumatic tire according to claim 8 or 9 , characterized in that. The metal cord pneumatic tire according to any one of the claims 8 to 10 is a single wire. The pneumatic tire according to any one of claims 8 to 11 , wherein the number of ends of the metal cord is 10/50 mm or more and 30/50 mm or less. The pneumatic tire according to any one of claims 8 to 12 , wherein a strand diameter of the metal cord is 0.05 mm or more and 0.15 mm or less.

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