JP2024069056A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire capable of satisfying both efficiency of puncture repair with a puncture repair material and noise performance.SOLUTION: Provided is a pneumatic tire 1 having a tread part 2. In the pneumatic tire 1, a spongy sound absorbing body 9 is fixed to an inner surface 2b of the tread part 2. The sound absorbing body 9 has an outer peripheral surface 9a facing the outside in a tire radial direction. On the outer peripheral surface 9a, a plurality of grooves 10 and a plurality of land parts 11 divided by the plurality of grooves 10 are formed. Each of the plurality of grooves 10 has an opening width w1 of the outer peripheral surface 9a larger than a groove bottom width w2 of the groove 10 on a cross section in a direction orthogonal to a longitudinal direction of the groove 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pneumatic tire having a tread portion.

Conventionally, there is known a pneumatic tire in which a sound absorbing member is provided on the inner surface of the tread portion in order to reduce road noise. For example, the following Patent Document 1 proposes a pneumatic tire that further reduces road noise by forming a convex portion and a concave portion on the radially inward surface of the sound absorbing member.

JP 2019-108034 A

However, in the pneumatic tire of Patent Document 1, when a puncture in a portion where a sound absorbing device is fixed is repaired using a puncture repair material, the puncture repair material is supplied through the sound absorbing device, which can result in a long time being required to repair the puncture.

The present invention was devised in consideration of the above-mentioned circumstances, and its main objective is to provide a pneumatic tire that can achieve both efficient puncture repair using a puncture repair material and good noise performance by providing a sponge-like sound absorbing material on the inner surface of the tread.

The present invention is a pneumatic tire having a tread portion, in which a sponge-like sound absorbing material is fixed to the inner surface of the tread portion, the sound absorbing material has an outer peripheral surface facing outward in the tire radial direction, the outer peripheral surface is formed with a plurality of grooves and a plurality of land portions separated by the plurality of grooves, and each of the plurality of grooves has an opening width at the outer peripheral surface that is larger than the groove bottom width of the groove in a cross section perpendicular to the longitudinal direction of the groove.

By having the above-mentioned configuration, the pneumatic tire of the present invention can achieve both efficient puncture repair using the puncture repair material and noise performance.

1 is a cross-sectional view showing one embodiment of a pneumatic tire of the present invention. FIG. FIG. 2 is an enlarged cross-sectional view perpendicular to the longitudinal direction of the groove. 1 is an enlarged cross-sectional view perpendicular to the longitudinal direction of a groove in which a chamfered portion is formed. FIG. FIG. 2 is a development view of the sound absorber of the present embodiment as viewed from the outer circumferential surface side. FIG. 2 is a partial cross-sectional view of a pneumatic tire. FIG. 2 is a schematic diagram showing the material of the sound absorbing body. FIG. 13 is an explanatory diagram for explaining the manufacturing process of the sound absorber. FIG. 11 is a development view of a sound absorbing body according to another embodiment, as viewed from the outer circumferential surface side.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
1 is a tire meridian cross-sectional view including a rotation axis showing a pneumatic tire 1 of the present embodiment in a normal state. Here, the "normal state" refers to a state in which the pneumatic tire 1 is mounted on a normal rim, and is adjusted to a normal internal pressure and unloaded. Hereinafter, unless otherwise specified, the dimensions of each part of the pneumatic tire 1 are values measured in this normal state.

A "genuine rim" is a rim that is determined for each tire by a standard system that includes the standard on which the pneumatic tire 1 is based, for example, a "standard rim" for JATMA, a "design rim" for TRA, and a "measuring rim" for ETRTO. If there is no standard system that includes the standard on which the pneumatic tire 1 is based, a "genuine rim" is a rim that can be assembled and does not leak air, and that has the smallest rim diameter and the smallest rim width among the rims that can be assembled and do not leak air.

"Normal internal pressure" is the air pressure set for each tire by a standard system that includes the standards on which the pneumatic tire 1 is based, such as the "maximum air pressure" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO. "Normal internal pressure" is the air pressure set for each tire by the manufacturer, etc., if there is no standard system that includes the standards on which the pneumatic tire 1 is based.

As shown in FIG. 1, the pneumatic tire 1 of this embodiment has a tread portion 2 extending in an annular shape, a pair of sidewall portions 3 on both sides of the tread portion 2 in the tire axial direction, and bead portions 4 on the inner side of each sidewall portion 3 in the tire radial direction.

In this embodiment, the tread portion 2 has an outer surface 2a that constitutes a ground contact surface that contacts the road surface during running. The sidewall portion 3 desirably extends radially inward from both sides of the tread portion 2 in the tire axial direction. For example, a buttress portion is provided between the tread portion 2 and the sidewall portion 3. The bead portion 4 includes, for example, a portion that contacts the rim when assembled to the rim. The bead portion 4 in this embodiment has a bead core 5 that extends in an annular shape. The bead core 5 is formed, for example, from a steel wire.

The pneumatic tire 1 of this embodiment has a carcass 6 that extends from the tread portion 2 through a pair of sidewall portions 3 to a pair of bead portions 4, and a belt layer 7 that is disposed on the radially outer side of the carcass 6 in the tread portion 2. The pneumatic tire 1 may also have a band layer (not shown) disposed on the radially outer side of the belt layer 7.

The carcass 6 preferably extends in a toroidal shape between the bead cores 5 of the pair of bead portions 4 via the tread portion 2 and a pair of sidewall portions 3. The carcass 6 includes at least one, for example, one carcass ply 6A. In this embodiment, the carcass ply 6A extends between the pair of bead portions 4 via the tread portion 2 and a pair of sidewall portions 3.

The carcass ply 6A includes, for example, a main body portion 6a that extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and a folded-up portion 6b that is connected to the main body portion 6a and that is folded back around the bead core 5 from the inside to the outside in the tire axial direction. Such a carcass 6 improves the rigidity of the bead portion 4 and helps to improve the durability of the pneumatic tire 1.

The belt layer 7 includes at least one, for example, two belt plies 7A and 7B. The two belt plies 7A and 7B include, for example, a first belt ply 7A located on the inner side in the tire radial direction and a second belt ply 7B located on the outer side of the first belt ply 7A. Such a belt layer 7 can increase the rigidity of the tread portion 2 and improve the durability performance of the pneumatic tire 1.

In the pneumatic tire 1, for example, a bead apex 8 extending radially outward is disposed in the bead portion 4. The bead apex 8 extends radially outward from the bead core 5 between the main body portion 6a and the folded-back portion 6b of the carcass 6. Such a bead apex 8 improves the rigidity of the bead portion 4 and helps to improve the durability of the pneumatic tire 1.

The pneumatic tire 1 of this embodiment has a sponge-like sound absorbing body 9 on the inner surface 2b of the tread portion 2 in the tire radial direction. The sound absorbing body 9 preferably has an outer peripheral surface 9a facing outward in the tire radial direction and an inner peripheral surface 9b facing inward in the tire radial direction. The sound absorbing body 9 of this embodiment has the outer peripheral surface 9a fixed to the inner surface 2b of the tread portion 2.

Such a sound absorbing body 9 can reduce the road noise of the pneumatic tire 1 and improve the noise performance of the pneumatic tire 1. Here, the fixing of the sound absorbing body 9 includes not only bonding to the inner surface 2b with a pressure sensitive adhesive, adhesive, double-sided tape, etc., but also fixing via a sealant applied to the inner surface 2b.

Figure 2 is a partial perspective view of the sound absorber 9. As shown in Figures 1 and 2, the outer peripheral surface 9a of the sound absorber 9 of this embodiment has a plurality of grooves 10 and a plurality of land portions 11 separated by the plurality of grooves 10. In this embodiment, the plurality of land portions 11 are each fixed to the inner surface 2b of the tread portion 2 continuously along the longitudinal direction of the grooves 10.

Even if the pneumatic tire 1 is punctured, this sound absorbing body 9 can supply puncture repair material to the punctured area through the groove 10, and can reliably repair the punctured area. In addition, because the groove 10 forms a gap between the sound absorbing body 9 and the tread portion 2, the sound absorbing body 9 can suppress heat accumulation even when the tread portion 2 generates heat during high-speed driving.

Figure 3 is an enlarged cross-sectional view perpendicular to the longitudinal direction of the groove 10. As shown in Figures 2 and 3, in each of the multiple grooves 10 of this embodiment, in a cross section perpendicular to the longitudinal direction of the groove 10, the opening width w1 at the outer peripheral surface 9a is larger than the groove bottom width w2 of the groove 10.

Such a sound absorbing body 9 can reduce the adhesion area with the inner surface 2b of the tread portion 2, and it is easy to supply the puncture repair material to the puncture site while maintaining good noise performance of the pneumatic tire 1. Therefore, the pneumatic tire 1 of this embodiment can achieve both efficient puncture repair using the puncture repair material and good noise performance.

In a more preferred embodiment, the adhesion area between the outer peripheral surface 9a and the inner surface 2b is 10% to 48% of the projected area of the sound absorbing body 9 projected onto the inner surface 2b. Having an adhesion area of 10% or more of the projected area can suppress peeling of the sound absorbing body 9, which helps improve the durability of the pneumatic tire 1. Having an adhesion area of 48% or less of the projected area can increase the area of the inner surface 2b that is not in contact with the sound absorbing body 9, making puncture repair using the puncture repair material more efficient.

Each of the multiple grooves 10 has, for example, a trapezoidal cross-sectional shape in a cross section perpendicular to the longitudinal direction of the groove 10. Such grooves 10 can increase the opening width w1 at the outer peripheral surface 9a while suppressing a reduction in the volume of the sound absorbing body 9, thereby achieving both efficient puncture repair using the puncture repair material and good noise performance.

The grooves 10 of this embodiment have the same opening width w1 in a cross section perpendicular to the longitudinal direction of the groove 10. The grooves 10 of this embodiment also have the same groove bottom width w2 in a cross section perpendicular to the longitudinal direction of the groove 10. Such a sound absorber 9 can suppress imbalance in the direction perpendicular to the longitudinal direction and improve the noise performance of the pneumatic tire 1 in a balanced manner.

In the present embodiment, the land portions 11 have the same width w3 at the outer peripheral surface 9a in a cross section perpendicular to the longitudinal direction of the groove 10. The width w3 of the land portion 11 is preferably equal to the groove bottom width w2 of the groove 10. In the present embodiment, the land portions 11 have the same maximum width w4 in a cross section perpendicular to the longitudinal direction of the groove 10. The maximum width w4 of the land portion 11 is preferably equal to the opening width w1 of the groove 10.

In other words, it is desirable that the cross-sectional shape of the land portion 11 is equal to the cross-sectional shape of the groove 10. When such a sound absorber 9 is manufactured by cutting one material M (shown in FIG. 7) along the outer peripheral surface 9a, both cut pieces can be used as the sound absorber 9, which reduces manufacturing loss.

Each of the multiple grooves 10 preferably has an opening width w1 of 5 to 50 mm. By making the opening width w1 5 mm or more, a gap is reliably formed between the inner surface 2b, making it possible to efficiently repair a puncture in the pneumatic tire 1 using the puncture repair material. By making the opening width w1 50 mm or less, it is possible to maintain a good noise suppression effect of the sound absorber 9, and to improve the noise performance of the pneumatic tire 1.

Each of the multiple grooves 10 preferably has a groove bottom width w2 of 3 to 30 mm. By making the groove bottom width w2 3 mm or more, the cross-sectional area of the groove 10 can be increased, making it possible to efficiently repair a puncture using a puncture repair material. In addition, when the width w3 of the land portion 11 is equal to the groove bottom width w2, this also helps to maintain the strength of the sound absorber 9, improving the durability of the pneumatic tire 1. By making the groove bottom width w2 30 mm or less, the good noise suppression effect of the sound absorber 9 can be maintained, improving the noise performance of the pneumatic tire 1.

Each of the multiple grooves 10 preferably has a groove depth d of 1 to 10 mm from the outer peripheral surface 9a. With a groove depth d of 1 mm or more, a gap is reliably formed between the inner surface 2b, making it possible to efficiently repair a puncture using the puncture repair material. From this perspective, when the fastening means for the sound absorber 9 is an adhesive or double-sided tape, the groove depth d is preferably 2 mm or more, and when the sound absorber 9 is fastened via a sealant, the groove depth d is preferably 3 mm or more. With a groove depth d of 10 mm or less, the good noise suppression effect of the sound absorber 9 can be maintained, and the noise performance of the pneumatic tire 1 can be improved.

As shown in FIG. 3, it is preferable that each of the multiple grooves 10 has a pair of groove walls 10a. In this embodiment, each of the pair of groove walls 10a has a wall surface 10b that is inclined relative to the outer peripheral surface 9a. The inclination angle θ1 between the wall surface 10b and the outer peripheral surface 9a is preferably 95 to 170°. Since the inclination angle θ1 of such a groove 10 is an obtuse angle, it is possible to suppress a decrease in the strength of the land portion 11 and suppress peeling of the sound absorber 9, thereby improving the durability performance of the pneumatic tire 1.

Each of the grooves 10 preferably has a bottom surface 10c that connects a pair of wall surfaces 10b. In this embodiment, the inclination angle θ2 between the wall surface 10b and the bottom surface 10c is equal to the inclination angle θ1 between the wall surface 10b and the outer peripheral surface 9a. In such a sound absorber 9, the outer peripheral surface 9a and the bottom surface 10c can be formed parallel to each other, which is useful when manufacturing a single material M (shown in FIG. 7) by cutting along the outer peripheral surface 9a, allowing both cut surfaces to be used as the sound absorber 9.

Figure 4 is an enlarged cross-sectional view perpendicular to the longitudinal direction of the groove 10 in which the chamfered portion 10d is formed. As shown in Figure 4, for example, the chamfered portion 10d may be formed at each corner between the wall surface 10b and the bottom surface 10c. The chamfered portion 10d is formed, for example, in an arc shape in a cross section perpendicular to the longitudinal direction of the groove 10. Such a groove 10 can suppress a decrease in the strength of the land portion 11 and suppress peeling of the sound absorber 9, thereby improving the durability performance of the pneumatic tire 1.

In this embodiment, the corners between the wall surface 10b and the outer peripheral surface 9a are each formed with an arc-shaped chamfered portion 12. It is desirable that the chamfered portion 10d on the bottom surface 10c side and the chamfered portion 12 on the outer peripheral surface 9a side have the same radius of curvature r. Such a land portion 11 maintains good strength and helps to prevent the sound absorber 9 from peeling off.

The opening width w1 of the groove 10 in which the chamfered portion 12 is formed is preferably defined as the minimum distance between the chamfered portions 12. The groove bottom width w2 of the groove 10 in which the chamfered portion 10d is formed is, for example, defined as the length of the straight portion between the chamfered portions 10d. Similarly, the width w3 of the land portion 11 in which the chamfered portion 12 is formed is preferably defined as the length of the straight portion between the chamfered portions 12, and the maximum width w4 of the land portion 11 in which the chamfered portion 10d is formed is preferably defined as the maximum distance between the chamfered portions 10d.

The radius of curvature r of the chamfered portion 10d on the bottom surface 10c side and the chamfered portion 12 on the outer peripheral surface 9a side is preferably 0.5 to 2 mm. By making the radius of curvature r 0.5 mm or more, the strength of the land portion 11 is maintained and peeling of the sound absorber 9 due to deformation of the tread portion 2 during driving can be suppressed. By making the radius of curvature r 2 mm or less, the adhesion area of the sound absorber 9 is prevented from becoming smaller, and peeling of the sound absorber 9 can be suppressed.

Figure 5 is a development view of the sound absorber 9 of this embodiment seen from the outer peripheral surface 9a side. As shown in Figure 5, each of the multiple grooves 10 of this embodiment extends at an angle θ3 of less than 5° with respect to the tire circumferential direction. In other words, each of the multiple grooves 10 can be said to extend parallel to the tire circumferential direction. The sound absorber 9 has, for example, a pair of end faces 9c in the tire circumferential direction. It is desirable that each of the multiple grooves 10 is open at the pair of end faces 9c. Such a sound absorber 9 can achieve both a sufficient bonding area and strength, and can efficiently supply the puncture repair material while suppressing peeling of the sound absorber 9, thereby achieving both the durability of the pneumatic tire 1 and the efficiency of puncture repair using the puncture repair material.

Figure 6 is a partial cross-sectional view of the tire equator C of the pneumatic tire 1. Here, the tire equator C is the center position of the tread ground contact ends Te on both sides in the tire axial direction shown in Figure 1. The tread ground contact end Te is the outermost ground contact position in the tire axial direction when the pneumatic tire 1 in a normal state is loaded with a normal load and touches the ground on a flat surface with a camber angle of 0°. In other words, the tread ground contact width TW between the tread ground contact ends Te is the maximum width of the ground contact surface when the pneumatic tire 1 in a normal state is loaded with a normal load.

Here, "normal load" refers to the load determined for each tire by a standard system that includes the standard on which the pneumatic tire 1 is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. When there is no standard system that includes the standard on which the pneumatic tire 1 is based, "normal load" refers to the load determined for each tire by the manufacturer, etc.

As shown in FIG. 6, a gap L is formed between a pair of end faces 9c of the sound absorbing body 9 fixed to the inner surface 2b of the pneumatic tire 1 of this embodiment. Such a sound absorbing body 9 allows the puncture repair material to be supplied from the end faces 9c of the groove 10, making puncture repair using the puncture repair material more efficient.

The gap L between the end faces 9c is preferably 3 to 60 mm. With a gap L of 3 mm or more, the puncture repair material can be reliably supplied from the end face 9c of the groove 10. With a gap L of 60 mm or less, imbalance in the tire circumferential direction is suppressed, which helps to suppress the generation of vibrations, noise, etc. during high-speed driving.

At least one of the pair of end faces 9c, and in this embodiment, both, has a tapered surface 9d whose height in the tire radial direction gradually decreases. In this embodiment, the tapered surface 9d is formed in a flat shape. The tapered surface 9d may be formed in an arc shape, for example. Such a sound absorber 9 can suppress peeling from the end face 9c where stress is concentrated during running, and can improve the high-speed durability of the pneumatic tire 1.

The tapered surface 9d in this embodiment is formed on a part of the end face 9c. The height H of the part of the end face 9c where the tapered surface 9d is not formed is preferably 3 to 10 mm. Such a sound absorber 9 can suppress damage to the acute angle part of the end face 9c, and can improve the efficiency of the work of fixing it to the inner surface 2b of the tread portion 2. Note that the tapered surface 9d may be formed on the entire end face 9c, for example.

The tapered surface 9d is preferably inclined at an angle θ4 of 30 to 80° with respect to the inner circumferential surface 9b. By setting the angle θ4 with respect to the inner circumferential surface 9b to 30° or more, the sound absorber 9 can maintain a good sound absorbing effect. By setting the angle θ4 with respect to the inner circumferential surface 9b to 80° or less, the effect of suppressing peeling from the end surface 9c can be reliably achieved.

In the pneumatic tire 1 of this embodiment, a pair of end faces 9c of one sound absorbing body 9 are fixed with a gap L in the tire circumferential direction, but the present invention is not limited to this configuration, and the pneumatic tire 1 may have multiple sound absorbing bodies 9 fixed with a gap L in the tire circumferential direction. In this case, a gap L is formed between the end faces 9c of adjacent sound absorbing bodies 9. For such a pneumatic tire 1, the amount, shape, etc. of the sound absorbing bodies 9 can be selected according to the purpose.

As shown in FIG. 1, it is desirable that the width W1 of the sound absorber 9 in the tire axial direction is smaller than the width Wa of the belt layer 7 in the tire axial direction. Such a sound absorber 9 prevents the weight of the pneumatic tire 1 from becoming excessively large, and helps to improve the steering stability performance of the pneumatic tire 1.

Figure 7 is a schematic diagram showing the material M of the sound absorber 9, and Figure 8 is an explanatory diagram of the manufacturing process of the sound absorber 9. As shown in Figures 7 and 8, the sound absorber 9 of this embodiment is manufactured by cutting one piece of material M along the outer peripheral surface 9a. After the sound absorber 9 is cut, for example, along the groove 10 and the land portion 11, it is separated into two sound absorbers 9 by sliding it in the longitudinal direction of the groove 10.

The sound absorber 9 of this embodiment is asymmetric in the width direction in a cross section perpendicular to the longitudinal direction of the groove 10. Therefore, the sound absorber 9 of this embodiment can be used as two separated sound absorbers 9 of the same shape, further reducing manufacturing loss.

A sponge material is preferably used as the material M of the sound absorber 9. Examples of sponge materials include ether-based polyurethane, ester-based polyurethane, and polyethylene. Such a sound absorber 9 can reduce road noise while suppressing weight increase. Note that the sponge material is not limited to this type, and may be, for example, a rubber-based sponge material.

Figure 9 is an exploded view of a sound absorber 19 of another embodiment, seen from the outer peripheral surface 19a side. As shown in Figure 9, the outer peripheral surface 19a of the sound absorber 19 of this embodiment has a plurality of grooves 10 and a plurality of land portions 11 separated by the plurality of grooves 10, similar to the sound absorber 9 described above. In this embodiment, the plurality of land portions 11 are each fixed to the inner surface 2b (shown in Figure 1) of the tread portion 2 in a continuous manner along the longitudinal direction of the grooves 10.

Each of the multiple grooves 10 in this embodiment extends at an angle θ5 of 5 to 90° relative to the tire circumferential direction. The angle θ5 of the grooves 10 is effective for high-speed durability when it is, for example, about 15 to 45°, and is effective for supplying puncture repair material when it is close to 90°. For these reasons, the angle θ5 of the grooves 10 is preferably 45 to 60°. Such a sound absorbing body 19 helps to achieve both high-speed durability and efficient puncture repair.

The above describes in detail a particularly preferred embodiment of the present invention, but the present invention is not limited to the above-described embodiment and can be modified in various ways.

A pneumatic tire having the basic structure shown in Figure 1 was prototyped based on the specifications in Tables 1 and 2. Noise performance, puncture repair time, and durability performance were evaluated using the prototype tire. The main common specifications and evaluation methods are as follows.

<Common specifications>
Tire size: 215/55R17
Sound absorber width W1: 120mm
Sound absorbing material M: Ether polyurethane

<Noise performance>
A prototype tire with an air pressure adjusted to 250 kPa was mounted on a drum testing machine installed in an anechoic chamber, and the sound pressure was measured when the tire was traveling at 120 km/h under a load of 6.6 kN, and the tire was evaluated using an index that increases as the cavity resonance sound peak value decreases. The results are expressed as an index with Comparative Example 1 being set at 100, and a higher index value indicates a smaller cavity resonance sound peak value and better noise performance.

<Puncture repair time>
A puncture was created by penetrating a nail with a diameter of 5 mm into the central region of the tread of the prototype tire, and the puncture was repaired with a puncture repair material using a commercially available puncture repair kit. The time from the puncture site until the outflow of the puncture repair material stopped was measured, and the shorter the time, the higher the index value was evaluated. The results are expressed as an index with Comparative Example 1 being 100, and the higher the index value, the shorter the time until the outflow of the puncture repair material stopped, indicating that the puncture was repaired efficiently.

<Durability>
A prototype tire with an air pressure adjusted to 250 kPa was mounted on a drum testing machine, and the tire was run for 30,000 km at a speed of 120 km/h under a load of 6.6 kN, after which the state of the tire's internal structure was evaluated. The results are expressed as an index with Comparative Example 1 being 100, and the higher the value, the better the state of the tire's internal structure and the more excellent the durability performance.

The results of the evaluation are shown in Tables 1 and 2.

As a result of the evaluation, it was confirmed that the pneumatic tire of the embodiment had a shorter puncture repair time while maintaining the same noise performance as the comparative example, and that the efficiency of puncture repair using the puncture repair material was improved and noise performance was achieved at the same time. It was also confirmed that the pneumatic tire of the embodiment had superior durability performance compared to the comparative example.

[Additional Notes]
The present invention is as follows.

[Invention 1]
A pneumatic tire having a tread portion,
A sponge-like sound absorbing material is fixed to the inner surface of the tread portion,
The sound absorbing body has an outer circumferential surface facing outward in a tire radial direction,
A plurality of grooves and a plurality of land portions separated by the plurality of grooves are formed on the outer circumferential surface,
Each of the plurality of grooves has an opening width at the outer circumferential surface that is larger than a groove bottom width of the groove in a cross section perpendicular to a longitudinal direction of the groove.
Pneumatic tires.

[Invention 2]
The pneumatic tire according to claim 1, wherein the adhesion area between the outer peripheral surface and the inner surface is 10% to 48% of a projected area of the sound absorbing body projected onto the inner surface.

[The present invention 3]
3. The pneumatic tire according to claim 1, wherein each of the plurality of grooves has a trapezoidal cross-sectional shape in the cross section.

[Invention 4]
Each of the plurality of grooves has a pair of groove walls,
Each of the pair of groove walls has a wall surface inclined with respect to the outer circumferential surface,
The pneumatic tire according to any one of claims 1 to 3, wherein an inclination angle between the wall surface and the outer circumferential surface is 95 to 170°.

[Invention 5]
The pneumatic tire according to claim 4, wherein a chamfer is formed at each corner between the wall surface and the outer circumferential surface.

[Invention 6]
The grooves have the same groove bottom width in the cross section,
The plurality of land portions have the same width at the outer circumferential surface in the cross section,
6. The pneumatic tire according to any one of claims 1 to 5, wherein the width is equal to the groove bottom width.

[Invention 7]
The pneumatic tire according to any one of claims 1 to 6, wherein each of the plurality of grooves has a groove bottom width of 3 to 30 mm and a groove depth of 1 to 10 mm.

[The present invention 8]
The pneumatic tire according to any one of claims 1 to 7, wherein each of the plurality of grooves extends at an angle of 5 to 90 degrees with respect to the circumferential direction of the tire.

[The present invention 9]
The pneumatic tire according to any one of claims 1 to 7, wherein each of the plurality of grooves extends at an angle of less than 5° with respect to the circumferential direction of the tire.

[Invention 10]
The sound absorbing body has a pair of end faces in a tire circumferential direction,
The pneumatic tire according to any one of claims 1 to 9, wherein a gap is formed between the pair of end faces.

Reference Signs List 1 Pneumatic tire 2 Tread portion 2b Inner surface 9 Sound absorbing body 9a Outer peripheral surface 10 Groove 11 Land portion

Claims (10)

A pneumatic tire having a tread portion,
A sponge-like sound absorbing material is fixed to the inner surface of the tread portion,
The sound absorbing body has an outer circumferential surface facing outward in a tire radial direction,
A plurality of grooves and a plurality of land portions separated by the plurality of grooves are formed on the outer circumferential surface,
Each of the plurality of grooves has an opening width at the outer circumferential surface that is larger than a groove bottom width of the groove in a cross section perpendicular to a longitudinal direction of the groove.
Pneumatic tires. The pneumatic tire according to claim 1, wherein the adhesion area between the outer peripheral surface and the inner surface is 10% to 48% of the projected area of the sound absorbing body projected onto the inner surface. The pneumatic tire according to claim 1 or 2, wherein each of the plurality of grooves has a trapezoidal cross-sectional shape in the cross section. Each of the plurality of grooves has a pair of groove walls,
Each of the pair of groove walls has a wall surface inclined with respect to the outer circumferential surface,
3. The pneumatic tire according to claim 1, wherein an inclination angle between the wall surface and the outer circumferential surface is 95 to 170 degrees. The pneumatic tire according to claim 4, wherein each corner between the wall surface and the outer circumferential surface is chamfered. The grooves have the same groove bottom width in the cross section,
The plurality of land portions have the same width at the outer circumferential surface in the cross section,
The pneumatic tire according to claim 1 or 2, wherein the width is equal to the groove bottom width. The pneumatic tire according to claim 6, wherein each of the plurality of grooves has a groove bottom width of 3 to 30 mm and a groove depth of 1 to 10 mm. The pneumatic tire according to claim 1 or 2, wherein each of the plurality of grooves extends at an angle of 5 to 90° with respect to the tire circumferential direction. The pneumatic tire according to claim 1 or 2, wherein each of the plurality of grooves extends at an angle of less than 5° with respect to the tire circumferential direction. The sound absorbing body has a pair of end faces in a tire circumferential direction,
The pneumatic tire according to claim 9 , wherein a gap is formed between the pair of end faces.

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