PNEUMATIC TIRE

A pneumatic tire can have a tread portion. A sponge-like sound absorbing member can be on an inner surface of the tread portion. The sound absorbing member can have an outer peripheral surface facing outward in a tire radial direction. A plurality of grooves, and a plurality of land portions separated from each other by the plurality of grooves, can be formed in the outer peripheral surface. Each of the plurality of land portions can be attached to the inner surface continuously along a longitudinal direction of the groove.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to Japanese patent application JP 2022-121202, filed on Jul. 29, 2022, the entire contents of which is incorporated herein by reference in its entirety.

BACKGROUND

Field

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

Background Art

There has conventionally been a known pneumatic tire in which a sound absorbing part is provided on the inner surface of a tread portion in order to reduce road noise. For example, Japanese Laid-Open Patent Publication No. 2019-108034 proposes a pneumatic tire in which protrusions and recesses are formed on the inward surface in the tire radial direction of a sound absorbing part to further reduce road noise.

SUMMARY

According an aspect of the present disclosure, a pneumatic tire can include a tread portion wherein: a sponge-like sound absorbing member on an inner surface of the tread portion; the sound absorbing member can have an outer peripheral surface facing outward in a tire radial direction; a plurality of grooves, and a plurality of land portions separated from each other by the plurality of grooves, can be formed in the outer peripheral surface; and each of the plurality of land portions can be attached to the inner surface continuously along a longitudinal direction of the groove.

DETAILED DESCRIPTION

According to the inventors' study, heat generated by the tread of pneumatic tires at high speeds may cause a sound absorber to store heat and affect the tread.

Embodiments of the present disclosure have been made in view of the above circumstances, and an object of one or more embodiments of the present disclosure, among multiple objects, can be to provide a pneumatic tire in which a sponge-like sound absorbing member is provided on an inner surface of a tread portion and which can have improved high speed durability.

As a result of having configurations as described herein, the pneumatic tire according to one or more embodiments of the present disclosure can have improved high speed durability.

FIG.1is a tire meridian cross-sectional view of a pneumatic tire1according to one or more embodiments of the present disclosure in a standardized state, including the rotation axis of the pneumatic tire1. Here, the “standardized state” can be regarded as a state where: the pneumatic tire1is fitted on a standardized rim and adjusted to a standardized internal pressure; and no load is applied to the pneumatic tire1. Hereinafter, unless otherwise specified, dimensions and the like of components of the pneumatic tire1are values measured in the standardized state.

If there is a standard system including a standard on which the pneumatic tire1is based, the “standardized rim” can be regarded as a rim that is defined for each tire by the standard, and is, for example, the “standard rim” in the JATMA standard, the “Design Rim” in the TRA standard, or the “Measuring Rim” in the ETRTO standard. If there is no standard system including a standard on which the pneumatic tire1is based, the “standardized rim” can be regarded as a rim having the smallest rim diameter and having the smallest rim width, among rims to which the pneumatic tire1can be fitted and which do not cause air leakage.

If there is a standard system including a standard on which the pneumatic tire1is based, the “standardized internal pressure” can be regarded as an air pressure that is defined for each tire by each standard, and is the “maximum air pressure” in the JATMA standard, the maximum value indicated in the table “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in the TRA standard, or the “INFLATION PRESSURE” in the ETRTO standard. If there is no standard system including a standard on which the pneumatic tire1is based, the “standardized internal pressure” can be regarded as an air pressure that is defined for each tire by the manufacturer or the like.

As shown inFIG.1, the pneumatic tire1according to one or more embodiments of the present disclosure can have a tread portion2that extends annularly, a pair of sidewall portions3provided on both sides in the tire axial direction of the tread portion2, and bead portions4provided inward of the respective sidewall portions3in the tire radial direction.

The tread portion2of one or more embodiments of the present disclosure can have an outer surface2athat forms a ground-contact surface that is brought into contact with a road surface during running. The sidewall portions3can extend inward in the tire radial direction from both sides in the tire axial direction of the tread portion2. For example, a buttress portion can be provided between the tread portion2and each sidewall portion3. Each bead portion4can include, for example, a portion that is brought into contact with a rim when the tire1is fitted onto the rim. The bead portion4of one or more embodiments of the present disclosure can have a bead core5that extends annularly. The bead core5may be formed of, for example, a steel wire.

The pneumatic tire1of one or more embodiments of the present disclosure can have a carcass6that extends from the tread portion2to the pair of bead portions4through the pair of sidewall portions3, and a belt layer7provided outward of the carcass6in the tire radial direction in the tread portion2. The pneumatic tire1may have, for example, a band layer that is provided outward of the belt layer7in the tire radial direction.

The carcass6can extend toroidally between the bead cores5of the pair of bead portions4through the tread portion2and the pair of sidewall portions3. The carcass6can include at least one (e.g., one, or two, or more) carcass ply6A. The carcass ply6A of one or more embodiments of the present disclosure can extend on and between the pair of bead portions4through the tread portion2and the pair of sidewall portions3.

The carcass ply6A can include, for example, a body portion6athat extends from the tread portion2to the bead core5of the bead portion4through the sidewall portion3, and a turned-up portion6bthat can be connected to the body portion6aand turned up around the bead core5from the inside to the outside in the tire axial direction. Such a carcass6can enhance the stiffness of the bead portion4and can serve to improve the durability of the pneumatic tire1.

The belt layer7can include one or more (e.g., one, two, or more) belt plies7A and7B. The two belt plies7A and7B can include, for example, a first belt ply7A located on the inner side in the tire radial direction, and a second belt ply7B located outward of the first belt ply7A in the tire radial direction. Such a belt layer7can enhance the stiffness of the tread portion2and can serve to improve the durability of the pneumatic tire1.

The pneumatic tire1can have, for example, bead apexes8provided in the bead portions4and that can extend outward in the tire radial direction. For example, each bead apex8can extend outward in the tire radial direction from the bead core5, between the body portion6aand the turned-up portion6bof the carcass6. Such a bead apex8can enhance the stiffness of the bead portion4and can serve to improve the durability of the pneumatic tire1.

The pneumatic tire1of one or more embodiments of the present can have a sponge-like sound absorbing member9on an inner surface2bin the tire radial direction of the tread portion2. Put another way, the sound absorbing member9can have qualities typically associated with a sponge, for instance, porousness, compression and expansion properties, etc. (in addition to sound absorbing properties). The sound absorbing member9can have an outer peripheral surface9athat faces outward in the tire radial direction, and an inner peripheral surface9bthat faces inward in the tire radial direction. The sound absorbing member9of one or more embodiments of the present embodiment can be firmly attached at the outer peripheral surface9ato the inner surface2bof the tread portion2. Examples of the sponge material include ether-based polyurethane, ester-based polyurethane, and polyethylene. Such sound absorbing member9can reduce road noise while suppressing weight increase. The sponge material according to one or more embodiments of the disclosed subject matter, however, is not limited to such a mode, and may be, for example, a rubber-based sponge material.

Such sound absorbing member9can reduce the road noise of the pneumatic tire1. Here, the sound absorbing member9may be firmly attached to the inner surface2bby a sticky agent, an adhesive agent, a double-sided tape, or the like, or alternatively, may be fixed to the inner surface2bby a sealant or the like applied to the inner surface2b.

FIG.2is a partial perspective view of the sound absorbing member9. As shown inFIG.1andFIG.2, a plurality of grooves10, and a plurality of land portions11aseparated from each other by the plurality of grooves10, are formed in the outer peripheral surface9aof the sound absorbing member9of one or more embodiments of the present disclosure. In the present embodiment shown inFIG.2, the plurality of land portions11can be each firmly attached to the inner surface2bof the tread portion2continuously along a longitudinal direction of the groove10.

Spaces can be formed between such sound absorbing member9and the tread portion2by the grooves10. Therefore, when heat is generated by the tread portion2, for instance, during high speed running, heat accumulation by the sound absorbing member9can be reduced. Therefore, the pneumatic tire1according to one or more embodiments of the present disclosure can have improved high speed durability. In addition, when the pneumatic tire1has a puncture, the sound absorbing member9can allow a puncture repair material to be fed to a puncture area through the groove10, resulting in efficient puncture repair.

According to one or more embodiments, the attached area of the plurality of land portions11to the inner surface2bcan be 25% to 50% of the projected area of the sound absorbing member9onto the inner surface2b, for instance, such as from 27.5% to 47.5% or from 30% to 45%. As the attached area may be not less than 25% of the projected area, then even when the tread portion2becomes deformed (e.g., significantly deformed), for instance, during high speed running, the coming off of the sound absorbing member9can be suppressed, which can lead to an improvement in the high speed durability of the pneumatic tire1. As the attached area may be not greater than 50% of the projected area, the heat accumulation of the sound absorbing member9, for instance, during high speed running, can be reliably reduced, which can lead to an improvement in the high speed durability of the pneumatic tire1.

FIG.3is an enlarged cross-sectional view perpendicular to the longitudinal direction of the groove10according to one or more embodiments of the present disclosure. As shown inFIG.2andFIG.3, the plurality of grooves10can have the same cross-sectional shape in a cross-section thereof perpendicular to the longitudinal direction of the groove10. That is, the plurality of grooves10can have groove widths w1which are equal to each other. Such a sound absorbing member9can reduce non-uniformity in a direction perpendicular to the longitudinal direction, and therefore can improve the noise performance of the pneumatic tire1in a well-balanced manner.

The plurality of land portions11can be firmly attached to the inner surface2bof the tread portion2over widths w2which are equal to each other, in a cross-section thereof perpendicular to the longitudinal direction of the groove10(as shown inFIG.1), for instance. The width w2of each land portion11can be equal to the groove width w1of each groove10at the outer peripheral surface9a. In the case of such sound absorbing member9, when a single material is cut along the outer peripheral surface9aand thereby divided into two portions, both of the two portions can be used as the sound absorbing member9, which can result in a reduction in manufacturing loss.

The groove width w1of each groove10can be 3 to 10 mm at the outer peripheral surface9a, as an example. As the groove width w1may be not less than 3 mm, a space can be reliably formed between the groove10and the inner surface2b. Therefore, heat accumulation can be reduced, and efficiency of puncture repair can be improved. As the groove width w1may be not greater than 10 mm, a force applied to each land portion11can be reduced during running, and therefore, the coming off of the sound absorbing member9can be suppressed.

Each groove10can have a groove depth d of 1 to 10 mm from the outer peripheral surface9a, as an example. As the groove depth d may be not less than 1 mm, a space can be reliably formed between the groove10and the inner surface2b, and therefore, heat accumulation can be reduced, and efficiency of puncture repair can be improved. From such a viewpoint, in the case where the means for firmly attaching the sound absorbing member9is a sticky agent or a double-sided tape, the groove depth d can be not less than 2 mm, as an example. In the case where the sound absorbing member9is firmly attached by a sealant, the groove depth d can be not less than 3 mm, as an example. As the groove depth d may be not greater than 10 mm, a decrease in the strength of the land portions11due to the formation of the grooves10can be reduced, and therefore, the coming off of the sound absorbing member9can be suppressed.

As shown inFIG.3, each groove10can have a pair of groove walls10a. Each groove wall10acan have a wall surface10bthat is perpendicular to the outer peripheral surface9a. Such a groove10can contribute to both of the attached area and strength.

Each groove10can have a bottom surface10cthat connects the pair of wall surfaces10b. A chamfered portion10dcan be formed at each of corner portions between the wall surfaces10band the bottom surface10caccording to one or more embodiments of the present disclosure. The chamfered portion10dcan be formed, for example, in an arc shape in a cross-section thereof perpendicular to the longitudinal direction of the groove10. Such a groove10can reduce a decrease in the strength of the land portion11and can serve to suppress the coming off of the sound absorbing member9.

A chamfered portion12can be formed at each of corner portions between the wall surfaces10band the outer peripheral surface9aaccording to one or more embodiments of the present disclosure. The chamfered portion12can be formed, for example, in an arc shape in a cross-section thereof perpendicular to the longitudinal direction of the groove10. The chamfered portions10don the bottom surface10cand the chamfered portions12on the outer peripheral surface9acan have the same radius of curvature r according to one or more embodiments of the present disclosure. Such a land portion11can maintain good strength and serve to suppress the coming off of the sound absorbing member9.

The radius of curvature r of each of the chamfered portions10don the bottom surface10cand the chamfered portions12on the outer peripheral surface9acan be 0.5 to 2 mm, as an example. As the radius of curvature r may be not less than 0.5 mm, the strength of the land portion11can be maintained, and therefore, the coming off of the sound absorbing member9due to the deformation of the tread portion2during running can be suppressed. As the radius of curvature r may be not greater than 2 mm, a decrease in the attached area of the sound absorbing member9can be reduced, which can lead to suppression of the coming off of the sound absorbing member9.

FIG.4is a development of the sound absorbing member9according to one or more embodiments of the present disclosure as viewed from above the outer peripheral surface9a. As shown inFIG.4, each groove10can extend in parallel to the tire circumferential direction. The sound absorbing member9can have, for example, a pair of end surfaces9cin the tire circumferential direction. Each groove10can be open at the pair of end surfaces9c. Such a sound absorbing member9can have, as examples, one or both of a preferable attached area and a preferable strength, and can reduce heat accumulation of the sound absorbing member9and improve efficiency of puncture repair in addition to suppression of the coming off of the sound absorbing member9.

FIG.5is a partial cross-sectional view of the pneumatic tire1taken at a tire equator C, according to one or more embodiments of the present disclosure. Here, as shown inFIG.1, the tire equator C can be located at the center position between tread ground-contact ends Te on both sides in the tire axial direction. The tread ground-contact ends Te can be or can be regarded as outermost ground-contact positions in the tire axial direction, for instance, when a standardized load is applied to the pneumatic tire1in the standardized state and the tire1is brought into contact with a flat surface at a camber angle of 0°. In other words, a tread ground-contact width TW between the tread ground-contact ends Te can be or can be regarded as the maximum width of a ground-contact surface, for instance, when a standardized load is applied to the pneumatic tire1in the standardized state.

If there is a standard system including a standard on which the pneumatic tire1is based, the “standardized load” can be regarded as a load that is defined for each tire by each standard, and is the “maximum load capacity” in the JATMA standard, the maximum value indicated in the table “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in the TRA standard, or the “LOAD CAPACITY” in the ETRTO standard. If there is no standard system including a standard on which the pneumatic tire1is based, the “standardized load” can be regarded as a load that is defined for each tire by the manufacturer or the like.

As shown inFIG.5, a space L can be formed between the pair of end surfaces9cof the sound absorbing member9firmly attached to the inner surface2bof the pneumatic tire1of the present embodiment. Such a sound absorbing member9can allow the puncture repair material to be fed from the end surface9cof the groove10, which can result in efficient puncture repair.

The space L between the end surfaces9ccan be 3 to 60 mm, for instance. As the space L may be not less than 3 mm, the puncture repair material can be reliably fed from the end surface9cof the groove10. Additionally or alternatively, as the space L may be not greater than 60 mm, non-uniformity in the tire circumferential direction can be reduced, leading to suppression of occurrence of vibrations, noise, and the like during high speed running.

At least one (e.g., in the present embodiment, both) of the pair of end surfaces9ccan have a tapered surface9dwhose height in the tire radial direction may gradually become smaller. The tapered surface9dcan be formed in a flat surface shape, according to one or more embodiments of the present disclosure. The tapered surface9dmay, for example, be formed in an arc shape. The coming off of such sound absorbing member9from the end surface9c, at which stress may be concentrated during running, can be suppressed, which can lead to an improvement in the high speed durability of the pneumatic tire1.

The tapered surface9dcan be formed in a portion of the end surface9c. The portion of the end surface9cin which the tapered surface9dis not formed can have a height H of 3 to 10 mm, as an example. In such sound absorbing member9, damage to a sharp portion of the end surface9ccan be reduced, which can lead to an improvement in efficiency of the work of firmly attaching the sound absorbing member9to the inner surface2bof the tread portion2. It should be noted that the tapered surface9dmay be formed throughout the end surface9c, for example.

The tapered surface9dcan be inclined at angle α of 30 to 80° with respect to the inner peripheral surface9b, as an example. As the angle α with respect to the inner peripheral surface9bmay be not less than 30°, the effect of absorbing sound by the sound absorbing member9can be maintained at a satisfactory level. As the angle α with respect to the inner peripheral surface9bmay be not greater than 80°, the effect of suppressing the coming off of the sound absorbing member9from the end surface9ccan be reliably achieved.

In the pneumatic tire1according to one or more embodiments of the present disclosure, the single sound absorbing member9can be firmly attached with the space L formed between the pair of end surfaces9cin the tire circumferential direction. The pneumatic tire1according to one or more embodiments of the present disclosure, however, may not be limited to such a mode. Alternatively, in the pneumatic tire1according to one or more embodiments of the present disclosure, a plurality of sound absorbing members9may be firmly attached with spaces L formed in the tire circumferential direction. In that case, a space L can be formed between the end surfaces9cof adjacent sound absorbing members9. For such pneumatic tire1, the quantity, shape, and the like of the sound absorbing members9can be selected, depending on the purpose.

As shown inFIG.1, a width W1in the tire axial direction of the sound absorbing member9can be smaller than a width Wain the tire axial direction of the belt layer7. With such sound absorbing member9, an excessive increase in the weight of the pneumatic tire1can be suppressed, which can lead to an improvement in the handling stability of the pneumatic tire1.

FIG.6is a development of a sound absorbing member19according to another embodiment as viewed from above an outer peripheral surface19athereof. As shown inFIG.6, a plurality of grooves10, and a plurality of land portions11separated from each other by the plurality of grooves10, can be formed in the outer peripheral surface19aof the sound absorbing member19of the present embodiment, as in the above-described sound absorbing member9. In the present embodiment as well, the plurality of land portions11can be each firmly attached to the inner surface2bof the tread portion2(e.g., as shown inFIG.1) continuously along a longitudinal direction of the groove10.

Each groove10of the present embodiment can extends at an angle θ of 1 to 90° with respect to the tire circumferential direction, as an example. In the case where the angle θ of the groove10is, for example, about 15 to 45°, the groove10can effectively contribute to high speed durability. In the case where the angle θ of the groove10is close to 900 (e.g. plus or minus three degrees), the groove10can effectively contribute to feeding of the puncture repair material. Therefore, the angle θ of the groove10may be 45 to 60°, according to one or more embodiments of the present disclosure. Such sound absorbing member19can serve to achieve both high speed durability and efficiency of puncture repair.

FIG.7is a cross-sectional view of a sound absorbing member29according to still another embodiment. As shown inFIG.7, a plurality of grooves10, and a plurality of land portions11separated from each other by the plurality of grooves10, can be formed in an outer peripheral surface29aof the sound absorbing member29of the present embodiment, as in the above-described sound absorbing member9. In the present embodiment as well, the plurality of land portions11can each be firmly attached to the inner surface2bof the tread portion2(e.g., shown inFIG.1) continuously along a longitudinal direction of the groove10.

The sound absorbing member29of the present embodiment can have a protrusion-and-recess structure30formed in an inner peripheral surface29bthereof. The protrusion-and-recess structure30can include, for example, recesses30aand protrusions30b. The protrusion-and-recess structure30can be formed independently of the shape of the grooves10in the outer peripheral surface29a. The protrusion-and-recess structure30may not be limited to the illustrated form, and may have any shape. The inner peripheral surface29bof such a sound absorbing member29can have a shape advantageous to a reduction in road noise, which can result in a further improvement in noise performance.

FIG.8is a cross-sectional view of a sound absorbing member39according to still another embodiment. As shown inFIG.8, a plurality of grooves40, and a plurality of land portions41separated from each other by the plurality of grooves40, can be formed in an outer peripheral surface39aof the sound absorbing member39of the present embodiment. In the present embodiment as well, the plurality of land portions41can each be firmly attached to the inner surface2bof the tread portion2(e.g., as shown inFIG.1) continuously along a longitudinal direction of the groove40.

Each groove40of the present embodiment can have a pair of groove walls40a. Each groove wall40aof the present embodiment can have a wall surface40binclined with respect to the outer peripheral surface39a. Such groove40can enhance the strength of the land portion41, which can be effective in the case where the sound absorbing member39may have a smaller attached area.

FIG.9is a cross-sectional view of a sound absorbing member49according to still another embodiment. As shown inFIG.9, a plurality of grooves10, and a plurality of land portions11separated from each other by the plurality of grooves10, can be formed in an outer peripheral surface49aof the sound absorbing member49of the present embodiment, as in the above-described sound absorbing member9. In the present embodiment as well, the plurality of land portions11can be each firmly attached to the inner surface2bof the tread portion2(e.g., shown inFIG.1) continuously along a longitudinal direction of the groove10.

The sound absorbing member49of the present embodiment can be asymmetric in a width direction in a cross-section thereof perpendicular to the longitudinal direction of the groove10. In the case of the sound absorbing member49, when a single material is cut along the outer peripheral surface49aand thereby divided into two portions, both of the two portions can be used as the sound absorbing members49having the same shape, which can result in a further reduction in manufacturing loss.

Although the particular embodiments have been described in detail above, embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications can be made to implement various embodiments of the present disclosure.

Embodiments of the disclosed subject matter can also be as set forth according to the following brackets.[1]

A pneumatic tire including a tread portion, whereina sponge-like sound absorbing member is provided on an inner surface of the tread portion,the sound absorbing member has an outer peripheral surface facing outward in a tire radial direction,a plurality of grooves, and a plurality of land portions separated from each other by the plurality of grooves, are formed in the outer peripheral surface, andeach of the plurality of land portions is firmly attached to the inner surface continuously along a longitudinal direction of the groove.[2]

The pneumatic tire according to [1], wherein an attached area of the plurality of land portions to the inner surface is 25% to 50% of a projected area of the sound absorbing member onto the inner surface.[3]

The pneumatic tire according to [1] or [2], wherein the plurality of grooves have cross-sectional shapes that are the same as each other, in a cross-section thereof perpendicular to the longitudinal direction of the groove.[4]

The pneumatic tire according to any one of [1] to [3], whereinthe plurality of land portions are firmly attached to the inner surface over widths that are equal to each other, in the cross-section, andeach of the widths is equal to a groove width of each of the plurality of grooves at the outer peripheral surface.[5]

The pneumatic tire according to any one of [1] to [4], whereineach of the plurality of grooves has a pair of groove walls, andeach of the pair of groove walls has a wall surface perpendicular to the outer peripheral surface.[6]

The pneumatic tire according to any one of [1] to [5], wherein a chamfered portion is formed at each of corner portions between the wall surfaces and the outer peripheral surface.[7]

The pneumatic tire according to any one of [1] to [6], wherein each of the plurality of grooves has a groove width of 3 to 10 mm at the outer peripheral surface and a groove depth of 1 to 10 mm.[8]

The pneumatic tire according to any one of [1] to [7], wherein each of the plurality of grooves extends at an angle of 1 to 90° with respect to a tire circumferential direction.[9]

The pneumatic tire according to any one of [1] to [8], wherein each of the plurality of grooves extends in parallel to a tire circumferential direction.[10]

The pneumatic tire according to any one of [1] to [9], whereinthe sound absorbing member has a pair of end surfaces in the tire circumferential direction, anda space is formed between the pair of end surfaces.[11]

The pneumatic tire according to any one of [1] to [10], wherein at least one of the pair of end surfaces has a tapered surface whose height in the tire radial direction gradually becomes smaller.[12]

A pneumatic tire comprising:a tread portion; anda sound absorber on an inner surface of the tread portion,wherein the sound absorber defines an outer peripheral surface facing outward in a tire radial direction and an inner peripheral surface facing inward in the tire radial direction,wherein the sound absorber includes:a plurality of grooves, which extend from a first side of the sound absorber to a second side of the sound absorber, on the outer peripheral surface, anda plurality of land portions, which extend from the first side of the sound absorber to the second side of the sound absorber, on the outer peripheral surface, the plurality of land portions being separated from each other by respective ones of the plurality of grooves,wherein each of the plurality of land portions is fixedly attached to the inner surface of the tread portion continuously along a longitudinal direction of the plurality of grooves,wherein a maximum thickness of the sound absorber is less than a maximum depth of the plurality of grooves,wherein a cross-section of each of the plurality of grooves is the same,wherein a valley portion of each of the plurality of grooves is flat, andwherein the grooves are open at each of the first side of the sound absorber and the second side of the sound absorber.[13]

The pneumatic tire according to [12], wherein the first side of the sound absorber is a first end of the sound absorber, and the second side of the sound absorber is a second end of the sound absorber opposite the first end in the longitudinal direction of the plurality of grooves.[14]

The pneumatic tire according to [12] or [13], wherein a first width of at least some of the plurality of grooves is the same as a second width of at least some of the plurality of land portions.[15]

The pneumatic tire according to any one of [12] to [14], wherein no portion of each of the plurality of grooves is directly fixedly attached to the inner surface of the tread portion.