JP6981227B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of improving high-speed durability by adding a heat conductive member and preventing the heat conductive member from peeling off.

In a pneumatic tire, one of the causes of noise is the cavity resonance sound due to the vibration of the air filled inside the tire. This cavity resonance sound is generated by the tread portion vibrating due to the unevenness of the road surface when the tire is rolled, and the vibration of the tread portion vibrating the air inside the tire.

As a method for reducing noise due to such a cavity resonance phenomenon, it has been proposed to dispose a sound absorbing material in a cavity formed between a tire and a wheel rim. More specifically, a band-shaped sound absorbing material is adhered to a region corresponding to a tread portion on the inner surface of the tire (see, for example, Patent Documents 1 and 2).

However, when a sound absorbing material is adhered to the inner surface of the tire in order to reduce the cavity resonance sound, when the heat generation of the pneumatic tire increases with high speed running, the heat insulating effect of the sound absorbing material causes the tread portion to enter the tire cavity portion. Heat dissipation is hindered and heat tends to accumulate in the tread. When the temperature of the pneumatic tire becomes high in this way, there is a problem that the high-speed durability thereof is lowered.

On the other hand, a sheet-shaped heat conductive member is installed between the inner surface of the tire and the sound absorbing material, and the heat conductive member is arranged so as to extend outward from the area where the sound absorbing material is attached, and the heat absorbing member has sound absorbing material. A heat radiating portion protruding from the material is formed (see, for example, Patent Document 3). When, for example, a metal foil or a resin layer is used as a material constituting such a heat conductive member, the heat conductive member cannot cope with repeated deformation and stress during traveling, and the tire and the heat conductive member There is a problem that peeling occurs between them.

Japanese Unexamined Patent Publication No. 2002-67608 Japanese Unexamined Patent Publication No. 2005-138760 Japanese Unexamined Patent Publication No. 2016-137882

An object of the present invention is to provide a pneumatic tire capable of improving high-speed durability by adding a heat conductive member when adhering a sound absorbing material to the inner surface of the tire and preventing the heat conductive member from peeling off. To provide.

Pneumatic tires for achieving the above object include a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a tire diameter of these sidewall portions. In a pneumatic tire having a pair of bead portions arranged inside in the direction and having a sound absorbing material adhered to the inner surface of the tire, a heat conductive member inserted between the inner surface of the tire and the sound absorbing material, and the inner surface of the tire. It has a first adhesive layer interposed between the heat conductive member and a second adhesive layer interposed between the heat conductive member and the sound absorbing material, and the thickness of the second adhesive layer. The ratio A / B of the thickness A of the first adhesive layer to B is in the range of 1.1 to 150, and the heat conductive member is arranged so as to project from the area where the sound absorbing material is attached. Is to be.

In the present invention, in a pneumatic tire in which a sound absorbing material is adhered to a region corresponding to a tread portion on the inner surface of the tire, a heat conductive member is inserted between the inner surface of the tire and the sound absorbing material, and the heat conductive member is attached with the sound absorbing material. Since it is arranged so as to project from the attached area, the heat generated by the pneumatic tire during high-speed running is transferred to the heat conductive member and radiated into the tire cavity. Therefore, even when the sound absorbing material is adhered to the inner surface of the tire, the high-speed durability of the pneumatic tire can be improved. Further, the ratio A / B of the thickness A of the first adhesive layer to the thickness B of the second adhesive layer is in the range of 1.1 to 150, and the first adhesive layer is larger than the second adhesive layer. Since it is configured to be thick, it has excellent flexibility, and it is possible to mitigate the influence of repeated deformation and stress of the tire during running on the heat conductive member. As a result, it is possible to prevent damage or peeling of the heat conductive member and improve the load durability of the pneumatic tire.

In the present invention, the thickness A of the first adhesive layer is preferably 0.1 mm to 3.0 mm. In providing the first adhesive layer, sufficient flexibility can be ensured while suppressing an increase in weight and a decrease in heat dissipation.

In the present invention, the thickness B of the second adhesive layer is preferably 0.03 mm to 0.07 mm. In providing the second adhesive layer, sufficient adhesiveness can be ensured while suppressing deterioration of rolling resistance due to an increase in weight.

In the present invention, the length of the heat conductive member in the tire width direction is preferably 110% to 200% of the length of the sound absorbing material in the tire width direction. When arranging the heat conductive member, it is possible to sufficiently secure the amount of heat radiated into the tire cavity while suppressing the increase in weight.

In the present invention, the thermal conductivity of the heat conductive member is preferably 5.0 W / (m · K) or more. By using a heat conductive member having excellent heat conductivity, the heat dissipation effect can be improved.

In the present invention, the heat conductive member is preferably made of a metal foil. As a result, high thermal conductivity can be ensured, and a sufficient heat dissipation effect can be obtained.

In the present invention, the first adhesive layer can be made of a sealant material. As a result, the adhesiveness of the sealant material makes it possible to adhere to the inner surface of the tire and to obtain a puncture sealability.

In the present invention, the thickness of the heat conductive member is preferably 0.001 mm to 0.15 mm. When arranging the heat conductive member, it is possible to obtain a sufficient heat dissipation effect while suppressing a decrease in durability of the heat conductive member against out-of-plane bending stress.

In the present invention, it is preferable that the heat conductive member has a notch at least at the end in the tire width direction. When the heat conductive member has poor elasticity, the heat conductive member cannot follow the deformation of the tire and easily peels off from the inner surface of the tire. However, by providing a notch at the end of the heat conductive member in the tire width direction, the heat conductive member can easily follow the deformation of the tire, and the adhesiveness to the inner surface of the tire can be improved.

In the present invention, it is preferable that the heat conductive member has a three-dimensional structure at least at the end portion in the tire width direction. By forming the end portion of the heat conductive member in the tire width direction into a three-dimensional structure, the heat dissipation effect of the heat conductive member can be further enhanced.

It is a meridian cross-sectional view which shows an example of the pneumatic tire which comprises embodiment of this invention. It is an equator line sectional view which shows the pneumatic tire which concerns on embodiment of this invention. It is a perspective view which shows the sound absorbing material and the heat conduction member adhered to the inner surface of the pneumatic tire of this invention. It is sectional drawing which shows the sound absorbing material and the heat conduction member adhered to the inner surface of the pneumatic tire of this invention. It is a developed view which shows the sound absorbing material and the heat conduction member adhered to the inner surface of the pneumatic tire of this invention. It is a perspective view which shows the modification of the sound absorbing material and the heat conduction member adhered to the inner surface of the pneumatic tire of this invention. It is a perspective view which shows the other modification of the sound absorbing material and the heat conduction member adhered to the inner surface of the pneumatic tire of this invention. It is a meridian cross-sectional view which shows the modification of the pneumatic tire which concerns on embodiment of this invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 show a pneumatic tire according to an embodiment of the present invention, and FIGS. 3 to 5 show a sound absorbing material and a heat conductive member adhered to the inner surface of the tire. In FIGS. 3 to 5, Tc is the tire circumferential direction and Tw is the tire width direction.

As shown in FIGS. 1 and 2, the pneumatic tire of the present embodiment has a tread portion 1 extending in the tire circumferential direction and forming an annular shape, and a pair of sidewall portions arranged on both sides of the tread portion 1. 2 and a pair of bead portions 3 arranged inside the sidewall portions 2 in the tire radial direction.

A carcass layer 4 is mounted between the pair of bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the radial direction of the tire, and is folded back from the inside to the outside of the tire around the bead core 5 arranged in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross section is arranged on the outer periphery of the bead core 5.

On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of reinforcing cords that are inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to intersect each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set to, for example, in the range of 10 ° to 40 °. As the reinforcing cord of the belt layer 7, a steel cord is preferably used. At least one belt cover layer 8 having reinforcing cords arranged at an angle of, for example, 5 ° or less with respect to the tire circumferential direction is arranged on the outer peripheral side of the belt layer 7 for the purpose of improving high-speed durability. There is. As the reinforcing cord of the belt cover layer 8, an organic fiber cord such as nylon or aramid is preferably used.

The above-mentioned tire internal structure shows a typical example of a pneumatic tire, but is not limited thereto.

In the pneumatic tire, as shown in FIGS. 1 to 5, one band-shaped sound absorbing material 11 is adhered to the region corresponding to the tread portion 1 of the tire inner surface 10 along the tire circumferential direction. The area where the sound absorbing material 11 is attached is the entire surface of the surface where the sound absorbing material 11 comes into contact with the inner surface 10 of the tire. The sound absorbing material 11 is made of a porous material having open cells, and has predetermined sound absorbing characteristics based on the porous structure. Polyurethane foam may be used as the porous material of the sound absorbing material 11.

A sheet-shaped heat conductive member 12 extending in the tire circumferential direction is installed between the tire inner surface 10 and the sound absorbing material 11. The heat conductive member 12 is arranged so as to project from the area where the sound absorbing material 11 is attached, and the heat conductive member 12 is formed with a heat radiating portion 12A protruding from the sound absorbing material 11. It is desirable that the heat radiating portions 12A are provided on both sides of the heat conductive member 12 in the width direction, but such heat radiating portions 12A may be arranged only on one side of the heat conductive member 12 in the width direction.

An adhesive layer 13 extending in the circumferential direction of the tire is inserted between the inner surface 10 of the tire and the heat conductive member 12 and between the heat conductive member 12 and the sound absorbing material 11, and the adhesive layer 13 allows both of them to be inserted. They are glued to each other. The adhesive layer 13 is composed of a first adhesive layer 14 interposed between the tire inner surface 10 and the heat conductive member 12, and a second adhesive layer 15 interposed between the heat conductive member 12 and the sound absorbing material 11. Has been done. The first adhesive layer 14 is configured to be thicker than the second adhesive layer 15. More specifically, as shown in FIG. 4, when the thickness of the first adhesive layer 14 is the thickness A and the thickness of the second adhesive layer 15 is the thickness B, the thickness A with respect to the thickness B. The ratio A / B of is configured to be in the range of 1.1 to 150.

As such an adhesive layer 13, a paste-like adhesive or a double-sided adhesive tape can be used. In particular, a double-sided adhesive tape made of an adhesive that does not contain a base material is preferable, and in that case, the heat dissipation of the tire is not hindered, and the thickness of the adhesive layer 13 can be made thin. Further, as the type of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 13, for example, an acrylic pressure-sensitive adhesive can be used. The first adhesive layer 14 and the second adhesive layer 15 constituting such an adhesive layer 13 may be composed of adhesives of the same quality as each other, or the first adhesive layer 14 may be excellent in thermal conductivity. The second pressure-sensitive adhesive layer 15 may be composed of a normal pressure-sensitive adhesive. The base material is a support that supports the pressure-sensitive adhesive.

In the above-mentioned pneumatic tire, the heat conductive member 12 is inserted between the inner surface 10 of the tire and the sound absorbing material 11, and the heat conductive member 12 is arranged so as to project from the attachment region of the sound absorbing material 11 at high speed. The heat generated by the pneumatic tire during traveling is transferred to the heat conductive member 12 and radiated into the tire cavity. Therefore, even when the sound absorbing material 11 is adhered to the inner surface 10 of the tire, the high-speed durability of the pneumatic tire can be improved. Further, the ratio A / B of the thickness A of the first adhesive layer 14 to the thickness B of the second adhesive layer 15 is in the range of 1.1 to 150, and the first adhesive layer 14 is the second adhesive. Since it is configured to be thicker than the layer 15, it is excellent in flexibility, and it is possible to mitigate the influence of repeated deformation and stress of the tire during traveling on the heat conductive member 12. As a result, it is possible to prevent the heat conductive member 12 from being damaged or peeled off, and to improve the load durability of the pneumatic tire.

In the pneumatic tire, the first adhesive layer 14 may be made of a sealant material. Any adhesive composition can be used as the sealant material. By using the sealant material as the first adhesive layer 14 in this way, it is possible to adhere to the inner surface 10 of the tire due to the adhesiveness of the sealant material, and it is possible to obtain a puncture sealability.

Further, the thickness A (see FIG. 4) of the first adhesive layer 14 is preferably 0.1 mm to 3.0 mm. In providing the first adhesive layer 14, sufficient flexibility can be ensured while suppressing an increase in weight and a decrease in heat dissipation. If the thickness A of the first adhesive layer 14 is smaller than 0.1 mm, the flexibility of the first adhesive layer 14 decreases, and conversely, if it is larger than 3.0 mm, the flexibility is ensured but the weight is excessive. And the heat dissipation will decrease.

Further, the thickness B (see FIG. 4) of the second adhesive layer 15 is preferably 0.03 mm to 0.07 mm. In providing the second adhesive layer 15, sufficient adhesiveness can be ensured while suppressing deterioration of rolling resistance due to an increase in weight. If the thickness B of the second adhesive layer 15 is smaller than 0.03 mm, the adhesiveness is lowered, and conversely, if it is larger than 0.07 mm, the weight is increased and the rolling resistance is deteriorated.

In the pneumatic tire, the length L2 of the heat conductive member 12 in the tire width direction is preferably in the range of 110% to 200% of the length L1 of the sound absorbing material 11 in the tire width direction. At this time, the length of the first adhesive layer 14 in the tire width direction is configured to be the same as the length L2 of the heat conductive member 12 in the tire width direction. When arranging the heat conductive member 12, it is possible to sufficiently secure the amount of heat radiated into the tire cavity while suppressing the increase in weight. If the length L2 of the heat conductive member 12 in the tire width direction is smaller than 110% of the length L1 of the sound absorbing material 11 in the tire width direction, a sufficient amount of heat radiation cannot be secured, and conversely, the sound absorbing material 11 If it exceeds 200% of the length L1 in the tire width direction, the weight will increase excessively.

In the pneumatic tire, the thermal conductivity of the heat conductive member 12 is preferably 5.0 W / (m · K) or more. The thermal conductivity of general rubber is 0.1 to 0.2 W / (m · K), and the thermal conductivity of ordinary acrylic having no thermal conductivity is 0.2 W / (m · K). .. By using the heat conductive member 12 having excellent heat conductivity, the heat generated by the pneumatic tire can be easily transferred, and a sufficient heat dissipation effect can be obtained in the tire cavity. Thermal conductivity is calculated based on ASTM E1530 provisions.

In particular, it is preferable that the heat conductive member 12 is made of a metal foil. Aluminum is preferable as the material of the metal foil, and the thermal conductivity of the aluminum foil is 160 W / (m · K). By using the metal foil as the heat conductive member 12 in this way, high heat conductivity can be ensured and a sufficient heat dissipation effect can be obtained.

Further, the thickness t (see FIG. 4) of the heat conductive member 12 is preferably 0.001 mm to 0.15 mm. In arranging the heat conductive member 12, it is possible to obtain a sufficient heat dissipation effect while suppressing a decrease in durability of the heat conductive member 12 against out-of-plane bending stress. If the thickness t of the heat conductive member 12 is smaller than 0.001 mm, the heat dissipation property is lowered, and conversely, if the thickness t is larger than 0.15 mm, the durability against out-of-plane bending stress is lowered.

FIG. 6 shows a modified example of the sound absorbing material and the heat conductive member adhered to the inner surface of the pneumatic tire of the present invention. In FIG. 6, the heat conductive member 12 has a plurality of notches 16 at least at the ends in the tire width direction. When the notch 16 is provided at the end of the heat conductive member 12 in the tire width direction, the heat conductive member 12 easily follows the deformation of the tire, and the adhesiveness of the heat conductive member 12 to the tire inner surface 10 is improved. be able to. In providing the notch 16, it is also possible to form the notch 16 over the entire width direction of the heat conductive member 12 and divide the heat conductive member 12 in the tire circumferential direction.

FIG. 7 shows another modification of the sound absorbing material and the heat conductive member adhered to the inner surface of the pneumatic tire of the present invention. In FIG. 7, the heat conductive member 12 has a three-dimensional structure at least at the end portion in the tire width direction. That is, a three-dimensional heat radiating portion 17 composed of a plurality of fins processed by bending the cut portion is formed at the end portion of the heat conductive member 12 in the tire width direction. By forming the end portion of the heat conductive member 12 in the tire width direction into a three-dimensional structure in this way, the heat dissipation effect from the end portion of the heat conduction member 12 in the tire width direction can be further enhanced. The end portion of the heat conductive member 12 in the tire width direction may be stretched in the tire circumferential direction to form wrinkles to form a three-dimensional structure.

FIG. 8 shows a modified example of the pneumatic tire of the present invention. It shows a modification of the pneumatic tire according to the embodiment of the present invention. The pneumatic tire shown in FIG. 8 has the same structure as the pneumatic tire of FIG. 1 except that the number of sound absorbing materials 11 to be attached is different. Specifically, in the embodiment shown in FIGS. 1 to 7, one strip-shaped sound absorbing material 11 is adhered along the tire circumferential direction in the region corresponding to the tread portion 1 of the tire inner surface 10, but FIG. 8 In the embodiment shown in FIG. 8, a plurality of strip-shaped sound absorbing materials 11 (two in FIG. 8) are adhered along the tire circumferential direction. The heat conductive member 12 is arranged so as to project from the attachment region of the sound absorbing material 11. That is, the heat radiating portions 12A exist at three locations, the central portion and both end portions of the heat conductive member 12 in the tire width direction. In this case, the length L1 of the sound absorbing material 11 in the tire width direction is the length between the ends of the two sound absorbing materials 11 located outside in the tire width direction.

With a tire size of 275 / 35R20, a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and these sidewall portions are arranged inside the tire radial direction. In a pneumatic tire having a pair of bead portions and a sound absorbing material bonded to a region corresponding to the tread portion on the inner surface of the tire along the circumferential direction of the tire, a heat conductive member inserted between the inner surface of the tire and the sound absorbing material. It has a first adhesive layer interposed between the inner surface of the tire and the heat conductive member, and a second adhesive layer interposed between the heat conductive member and the sound absorbing material, and the heat conductive member is made of the sound absorbing material. Arranged so as to project from the pasting area, the thickness A of the first adhesive layer, the thickness B of the second adhesive layer, the ratio A / B of the thickness A to the thickness B, and the sound absorbing material in the tire width direction. The tires of Examples 1 to 5 in which the ratio (L2 / L1 × 100%) of the length L2 of the heat conductive member in the tire width direction to the length L1 was set as shown in Table 1 were manufactured.

For comparison, it is the same as Example 1 except that the adhesive layer for adhering the sound absorbing material to the inner surface of the tire (referred to as the first adhesive layer in Table 1) does not protrude from the sound absorbing material and is not provided with the heat conductive member. A conventional tire having a structure was prepared. Further, a tire of Comparative Example having the same structure as that of Example 1 was prepared except that the thickness A of the first adhesive layer and the ratio A / B of the thickness A and the thickness B were different.

In Comparative Examples and Examples 1 to 5, aluminum foil (thickness 0.01 mm) having a thermal conductivity of 160 W / (m · K) was used as the heat conductive member.

High-speed durability, load durability (peeling) and load durability (mileage) were evaluated for these test tires by the following test methods, and the results are also shown in Table 1.

High speed durability:
Each test tire was assembled to a wheel with a rim size of 20 x 9.5J, and a running test was started with a drum tester under the conditions of an air pressure of 220 kPa, a load of 6.6 kN, and an initial speed of 150 km / h, and the speed was increased to 5 km every 10 minutes. The speed was increased by increasing / h, and the speed when a failure occurred in the tread portion of the tire was investigated, and the results are shown in Table 1. The higher this speed, the better the high-speed durability.

Load durability (peeling):
Assemble each test tire to a wheel with a rim size of 20 x 9.5J, and use it as a drum tester under the conditions that the air pressure is 250kPa, the running speed is 80km / h, the mileage is 2600km, and the load is increased by 10% every 80km from 8.3kN. After conducting a running test, the presence or absence of peeling on each adhesive surface of the sound absorbing material, the adhesive layer, and the heat conductive member was visually confirmed.

Load durability (mileage):
Each test tire is assembled on a wheel with a rim size of 20 x 9.5J, and a running test is started with a drum tester under the conditions of an air pressure of 250 kPa, a running speed of 80 km / h, and an initial load of 8.3 kN, and the load is applied every 80 km. It was increased by 10%, and the mileage when peeling occurred on the adhesive surface of any of the sound absorbing material, the adhesive layer and the heat conductive member was measured. The evaluation results are shown by an index with a comparative example of 100. The larger this index value is, the better the load durability (mileage) is.

As can be seen from Table 1, in comparison with the conventional examples, the high-speed durability was improved in all of Examples 1 to 5. Further, in comparison with the comparative example, in each of Examples 1 to 5, the load durability (peeling) and the load durability (mileage) were improved.

1 Tread part 2 Side wall part 3 Bead part 10 Tire inner surface 11 Sound absorbing material 12 Heat conductive member 12A Heat dissipation part 13 Adhesive layer 14 First adhesive layer 15 Second adhesive layer 16 Notch 17 Three-dimensional heat dissipation part

Claims (10)

A tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire radial direction of these sidewall portions. In the case of pneumatic tires with a sound absorbing material bonded to the inner surface of the tire,
A heat conductive member inserted between the inner surface of the tire and the sound absorbing material, a first adhesive layer interposed between the inner surface of the tire and the heat conductive member, and the heat conductive member and the sound absorbing material. It has a second adhesive layer intervening between them, and the ratio A / B of the thickness A of the first adhesive layer to the thickness B of the second adhesive layer is in the range of 1.1 to 150. , A pneumatic tire characterized in that the heat conductive member is arranged so as to project from a region to which the sound absorbing material is attached. The pneumatic tire according to claim 1, wherein the thickness A of the first adhesive layer is 0.1 mm to 3.0 mm. The pneumatic tire according to claim 1 or 2, wherein the thickness B of the second adhesive layer is 0.03 mm to 0.07 mm. The pneumatic tire according to any one of claims 1 to 3, wherein the length of the heat conductive member in the tire width direction is 110% to 200% of the length of the sound absorbing material in the tire width direction. The pneumatic tire according to any one of claims 1 to 4, wherein the heat conductive member has a thermal conductivity of 5.0 W / (m · K) or more. The pneumatic tire according to any one of claims 1 to 5, wherein the heat conductive member is made of a metal foil. The pneumatic tire according to any one of claims 1 to 6, wherein the first adhesive layer is made of a sealant material. The pneumatic tire according to any one of claims 1 to 7, wherein the heat conductive member has a thickness of 0.001 mm to 0.15 mm. The pneumatic tire according to any one of claims 1 to 8, wherein the heat conductive member has a notch at least at an end portion in the tire width direction. The pneumatic tire according to any one of claims 1 to 9, wherein the heat conductive member has a three-dimensional structure at least at an end portion in the tire width direction.

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