JP7095280B2 - tire - Google Patents

Description

The present invention relates to a tire capable of reducing the air column resonance sound generated by the main groove extending in the circumferential direction of the tire.

As one of the causes of noise outside the vehicle, the air column resonance sound generated from the main groove extending in the tire circumferential direction is known. This air column resonance sound is generated by the resonance of the internal air of the pipe surrounded by the main groove arranged in the tread portion and the road surface during traveling. Since this air column resonance sound has a high peak sound pressure level and includes a sound range having a jarring frequency of around 1000 Hz, it occupies a large part of tire noise.

Therefore, in the following Patent Document 1, in order to reduce the air column resonance sound, a sipe and a muffling chamber provided at the bottom of the sipe and having one end communicating with the main groove are provided in the land portion. Pneumatic tires have been proposed. In this tire, the anechoic chamber constitutes a Helmholtz-type resonator, and absorbs the energy of the air column resonance sound to reduce the air column resonance sound.

However, in the above proposal, the anechoic chamber is directly conducted to the main groove without passing through a small-diameter neck portion. Therefore, the energy absorption effect is insufficient, and further improvement is desired in order to reduce the air column resonance sound (outside noise).

Japanese Unexamined Patent Publication No. 2013-126842

An object of the present invention is to provide a tire capable of further reducing the air column resonance sound caused by the main groove and improving the noise performance outside the vehicle.

The present invention is a tire provided with a tread portion having a main groove extending in the circumferential direction of the tire and a plurality of land portions classified by the main groove.
At least one land area
A cavity that is substantially sealed inside the land portion and whose both ends in the length direction are interrupted inside the land portion.
A sound deadening means having a communication portion that communicates the cavity portion and the main groove is provided.

In the tire according to the present invention, it is preferable that the cavity extends in the tire circumferential direction.

In the tire according to the present invention, it is preferable that one or more of the muffling means are arranged within the ground contact range where the tread portion is in contact with the road surface.

In the tire according to the present invention, it is preferable that the muffling means has a first sipe extending from the cavity portion to the tread surface of the land portion.

In the tire according to the present invention, the communication portion communicates between the cavity portion and the main groove through the inside of the land portion, and the cross-sectional area perpendicular to the length direction is the length direction of the cavity portion. It is preferably composed of a small hole-shaped communication hole smaller than a right-angled cross-sectional area, and the sound deadening means preferably has a second sipe extending from the communication hole to the tread surface of the land portion.

In the tire according to the present invention, it is also preferable that the communication portion is composed of a fine groove-shaped communication groove provided on the tread surface of the land portion.

In the tire according to the present invention, the volume V (mm ³ ) of the cavity portion, the cross-sectional area S (mm ² ) perpendicular to the length direction of the communication portion, and the length L (mm) of the communication portion. Satisfies the following equation (1).
5.0 × 10 ^-5 ≦ S / (V × L) ≦ 3.0 × 10 ^-3 --- (1)

In the tire according to the present invention, the volume V of the cavity is preferably in the range of 20 to 4000 mm ³ .

In the tire according to the present invention, the cross-sectional area S of the communication portion is preferably in the range of 1.5 to 20 mm ² .

In the tire according to the present invention, the length L of the communication portion is preferably in the range of 2 to 50 mm.

In the present specification, "sipe" means, for example, a notch having a width of 0.8 mm or less and a block between the wall surfaces when touching the ground.

The "ground contact range" means the range of the ground contact portion where the tread portion comes into contact with the road surface when a regular load is applied to a tire in a reference state in which the rim is assembled on the regular rim and the tire is filled with the regular internal pressure.

The "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, JATTA is a standard rim, TRA is "Design Rim", or If it is ETRTO, it means "Measuring Rim". The "normal internal pressure" is the air pressure defined for each tire by the standard. If it is JATTA, it is the maximum air pressure. If it is TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", ETRTO. If so, it means "INFLATION PRESSURE", but in the case of passenger car tires, it is 180 kPa. The "regular load" is the load defined for each tire by the standard, and is the maximum load capacity for JATTA and the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA. If it is ETRTO, it is "LOAD CAPACITY".

In the present specification, unless otherwise specified, the dimensions and the like of each part of the tire are the values specified in the reference state (no load).

In the present invention, as described above, at least one land portion is provided with one or more sound deadening means. The muffling means has a cavity portion that is substantially sealed inside the land portion and both ends in the length direction are interrupted inside the land portion, and a communication portion that communicates the cavity portion with the main groove. The hollow portion and the communicating portion form a Helmholtz-type resonator, and the air column resonance sound due to the main groove can be reduced. Moreover, in the above resonator, the cavity portion conducts with the main groove via a communication portion having a small cross-sectional area. Therefore, the energy absorption effect is increased and the muffling effect of the air column resonance sound can be enhanced as compared with the case where the cavity portion is directly opened by the main groove.

Further, in the resonator, since the communication portion having a small cross-sectional area is interposed, the cavity portion is less likely to be deformed as compared with the case where the cavity portion is directly opened in the main groove, and the decrease in rigidity of the land portion can be suppressed to a low level.

Further, the volume of the cavity does not change during the period until the tread is worn and the cavity is exposed on the surface. Therefore, the muffling performance can be maintained. In addition, after the middle stage of wear where the cavity is exposed, the muffling performance will not be exhibited, but after the middle stage of wear, the groove volume of the main groove itself is reduced and the air column resonance sound is reduced, so it is necessary to muffle the sound. Is low, and there is no particular problem of noise outside the vehicle.

Further, after the middle stage of wear where the cavity is exposed, the cavity functions as a new tread groove, so that deterioration of wet performance due to the progress of wear can be suppressed.

It is a development view of the tread part of the tire of one Embodiment of this invention. It is an enlarged plan view which shows a part of the land part. It is a perspective view which shows the muffling means conceptually. FIG. 2 is a sectional view taken along the line AA of FIG. 2 showing a sound deadening means. (A) and (B) are conceptual diagrams explaining the action of the muffling means. (A) is a perspective view showing a case where the first sipe is a three-dimensional sipe in the muffling means, and (B) is a perspective view showing a case where the communicating portion is a communication groove in the muffling means. It is a development view of the tread part which shows the other example of the tire of this invention.

Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a developed view of a tread portion 2 of a tire 1 showing an embodiment of the present invention. In this example, the case where the tire 1 is a pneumatic tire for a passenger car is shown. However, it may be a pneumatic tire for a heavy-duty vehicle, for example, and may be configured as various tires such as a non-pneumatic tire (for example, an airless tire) in which the inside of the tire is not filled with pressurized air. ..

As shown in FIG. 1, the tread portion 2 of the tire 1 includes at least one main groove 3 that extends continuously in the tire circumferential direction. As a result, the tread portion 2 is divided into a plurality of land portions 4.

In this example, the case where the main groove 3 is composed of the center main grooves 3C and 3C arranged on both sides of the tire equator C and the shoulder main grooves 3S and 3S arranged on the tread end Te side is shown. As a result, the tread portion 2 of this example has the center land portion 4C between the center main grooves 3C and 3C, the middle land portion 4M between the center main groove 3C and the shoulder main groove 3S, and the shoulder main groove 3S and the tread end. It is divided into shoulder land 4S between Te.

However, the present invention is not limited to this, and as the main groove 3, for example, a structure in which a middle main groove (not shown) is arranged between the center main groove 3C and the shoulder main groove 3S, and the center main groove 3C is the tire equator. Various structures such as a structure arranged on C can be adopted.

As the main groove 3, a straight groove extending linearly in the tire circumferential direction, a zigzag groove extending in a zigzag shape (including a wavy shape), and the like can be appropriately adopted. However, a straight groove is preferable from the viewpoint of obtaining a higher advantage due to the action and effect of the present invention. The groove width W3 and the groove depth D3 (shown in FIG. 4) of the main groove 3 can be variously determined according to the custom.

At least one of the plurality of land portions 4 is equipped with one or more muffling means 5. In this example, one or more muffling means 5 are arranged in each of the middle land portions 4M and 4M, so that the air column resonance sound caused by each center main groove 3C can be reduced.

In this example, the middle land portions 4M and 4M and the center land portion 4C are formed as rib bodies that extend continuously in the tire circumferential direction. In the case of the main groove sandwiched by the rib body (land portion) in this way, the air column resonance sound is louder than that of the main groove sandwiched by the block row (land portion). Therefore, the advantages of the action and effect of the present invention can be further obtained.

As shown in FIGS. 2 and 3, the sound deadening means 5 includes a cavity portion 10 and a communication portion 11.

The cavity 10 is substantially sealed inside the middle land portion 4M, and both ends in the length direction are interrupted inside the middle land portion 4M. The cavity 10 has a cylindrical shape having a substantially constant cross section, and extends linearly through the inside of the middle land portion 4M. However, the cavity 10 may extend in a zigzag shape in the length direction.

The cavity 10 of this example extends in the tire circumferential direction. As a result, it is possible to suppress the decrease in rigidity of the middle land portion 4M caused by the cavity portion 10 and to form the cavity portion 10 while maintaining the dry running performance. The above-mentioned "extending in the tire circumferential direction" includes a case where the tire is inclined at an angle of 5 degrees or less with respect to the tire circumferential direction line. In this example, a case where a plurality of cavity portions 10 are arranged in a row on the tire circumferential direction line, particularly on the width center line (not shown) of the middle land portion 4M is shown.

The communication portion 11 communicates the cavity portion 10 with the main groove 3 (center main groove 3C in this example). The communication portion 11 of this example is composed of a small hole-shaped communication hole 13 that passes through the inside of the middle land portion 4M and conducts the cavity portion 10 and the main groove 3 (center main groove 3C in this example). The communication hole 13 has a cylindrical shape having a substantially constant cross section, and the cross-sectional area S perpendicular to the length direction thereof is smaller than the cross-sectional area S0 perpendicular to the length direction of the cavity 10. In this example, the case where the cross-sectional shape of the communication hole 13 is substantially circular is shown, but for example, a polygonal shape and an elliptical shape can be appropriately adopted.

The muffling means 5 of this example includes a first sipe 8 and a second sipe 9.

The first sipe 8 extends from the cavity 10 to the tread surface 4s of the middle land portion 4M. Specifically, the first sipe 8 is provided on the tread surface 4s and extends along the cavity 10 on the cavity 10. Therefore, the cavity 10 is formed so as to be continuous with the bottom of the first sipe 8.

When the first sipe 8 is grounded, the wall surface is closed, whereby the cavity 10 is sealed. That is, the case where the cavity 10 is "substantially sealed" includes the case where the wall surface is closed and the cavity 10 is sealed at the time of touchdown. If the groove does not block between the walls when touching the ground, it is not included in "substantially sealed".

The second sipe 9 extends from the communication hole 13 to the tread surface 4s of the middle land portion 4M. Specifically, the second sipe 9 is provided on the tread surface 4s and extends on the communication hole 13 along the communication hole 13. Therefore, the communication hole 13 is formed so as to be connected to the bottom of the second sipe 9. In this example, the second sipe 9 extends from the main groove 3 (center main groove 3C in this example) to the first sipe 8, one end of the second sipe 9 is opened by the center main groove 3C, and the other end is the first. It intersects 1 sipe 8 in a T shape. In this example, a flat straight sipe (one-dimensional sipe) is adopted as the first sipe 8 and the second sipe 9. If the intersection angle α between the second sipe 9 and the first sipe 8 is too small, the strength is lowered at the intersection, and rubber chipping or the like is likely to occur. Therefore, the crossing angle α is preferably 30 degrees or more, more preferably 40 degrees or more.

In such a muffling means 5, the wall surface of the first sipe 8 and the wall surface of the second sipe 9 are closed when the ground is touched. As a result, when grounded, the cavity 10 and the communication portion 11 can form a Helmholtz-type resonator H having an opening at one end, which is open only in the center main groove 3C.

As shown in FIGS. 5A and 5B, in the resonator H, the air K1 in the communication portion 11 acts as a mass and the air K2 in the cavity portion 10 acts as a spring to form a vibration system. Then, when a sound having the same frequency as the natural frequency f of the resonator H is incident, resonance occurs, and the energy of the sound is absorbed by the adhesive friction of the air K1.

Therefore, by setting the natural frequency of the resonator H according to the frequency to be reduced among the air column resonance sounds generated by the center main groove 3C, the sound of the frequency to be particularly reduced among the air column resonance sounds can be reduced. Can improve noise performance.

One or more such sound deadening means 5 are arranged within the ground contact range where the tread portion 2 is in contact with the road surface. In this example, in each middle land portion 4M, one or more muffling means 5 are arranged within the ground contact range. Thereby, during the tire rolling, one or more muffling means 5 are constantly present in the ground contact range in each middle land portion 4M, and the air column resonance sound from each center main groove 3C can be reduced.

Here, the natural frequency f of the resonator H is represented by the following equation (2). In the formula, c is the sound velocity (m / s), S is the cross-sectional area perpendicular to the length direction of the communication portion 11 (mm ² ), V is the volume of the cavity 10 (mm ³ ), and L is the length of the communication portion 11. (Mm), δ is the open end correction. Therefore, the natural frequency f can be freely adjusted by the cross-sectional area S (mm ² ), the volume V (mm ³ ), and the length L (mm). The end correction δ is insignificant and can be ignored.
f = c / 2π × √ {S / (V × (L + δ))} --- (2)

In the resonator H, it is preferable that the cross-sectional area S (mm ² ), the volume V (mm ³ ), and the length L (mm) satisfy the following equation (1).
5.0 × 10 ^-5 ≦ S / (V × L) ≦ 3.0 × 10 ^-3 --- (1)

In this case, the natural frequency f of the resonator H can be set in the range of approximately 3.8 × 10 ² to 2.96 × 10 ³ Hz. In particular, by setting S / (V × L) in the range of 2.2 × 10 ^-4 to 4.9 × 10 ^-4 , the natural frequency f is set to around 1000 Hz (for example, 800 to 1200 Hz), which is jarring. Can be set.

By providing the cavity 10 at the bottom of the first sipe 8, the first sipe 8 and the cavity 10 can be easily formed by using a tire vulcanization die having a conventional structure. That is, in the tire vulcanization mold, by using a blade in which a columnar body for forming a cavity is integrally attached to the tip of a blade body for forming the first sipe, the first sipe 8 and the cavity are formed during vulcanization. 10 can be formed at the same time. Similarly, by using a blade in which a columnar body for forming a communication hole is integrally attached to the tip of the blade body for forming the second sipe, a tire vulcanization die having a conventional structure can be used for the second sipe. 9 and the communication hole 13 can be formed at the same time.

When the first sipe 8 and the second sipe 9 intersect in a T shape, the rigidity of the middle land portion 4M tends to decrease. Therefore, as shown in FIG. 6A, it is particularly preferable to adopt the three-dimensional sipe 12 as the first sipe 8. The three-dimensional sipe 12 includes a zigzag portion, and the zigzag portion extends in a zigzag shape (including a wavy shape) along the length direction in a horizontal cross section parallel to the tread surface 4s, and is perpendicular to the length direction. In the vertical cross section, it extends in a zigzag shape (including wavy shape) along the depth direction. In such a three-dimensional sipe 12, the wall surface of the sipe forms a three-dimensional curved surface in which unevenness is repeated three-dimensionally. When the three-dimensional sipe 12 is in contact with the ground, the unevenness of the wall surface meshes with each other in the three-dimensional direction, and the rigidity of the middle land portion 4M can be maintained high. In particular, in the case of the so-called Miura fold structure in which the wall surface is a combination of parallelograms as the three-dimensional sipe 12, the meshing is tight and strong. Therefore, it is also preferable in terms of improving the airtightness of the cavity 10 and improving the sound deadening performance.

As shown in FIG. 2, the distance Lb from the connection position P where the communication portion 11 connects with the cavity portion 10 to one end in the length direction of the cavity portion 10 is 0.1 to 0, which is the length La of the cavity portion 10. It is preferably 9 times. By separating the connection position P from the end of the cavity 10 in this way, it is possible to suppress a decrease in the rigidity of the middle land portion 4M. Further, since the deformation of the cavity 10 is suppressed, it can contribute to the improvement of the muffling effect. From such a viewpoint, the distance Lb is more preferably in the range of 0.2 to 0.8 times the length La, and more preferably in the range of 0.3 to 0.7 times.

Further, in the sound deadening means 5, the volume V of the cavity portion 10 does not change during the period until the tread is worn and the cavity portion 10 is exposed on the surface. Therefore, the natural frequency f of the resonator H does not change, and the muffling performance can be maintained. Further, after the middle stage of wear where the cavity 10 is exposed, the muffling performance is not exhibited, but after the middle stage of wear, the groove volume itself of the main groove 3 is reduced and the need for muffling is reduced, so that noise outside the vehicle is particularly low. Problem does not occur.

Further, after the middle stage of wear where the cavity portion 10 is exposed, the cavity portion 10 functions as a new tread groove, so that deterioration of wet performance due to the progress of wear can be suppressed.

Further, as shown in FIG. 4, in order to maintain the rigidity of the middle land portion 4M and the hermeticity of the cavity portion 10, the sipe depth Hs from the tread surface 4s to the cavity portion 10 is 2 mm or more, and further 3 mm. The above is preferable. The upper limit of the sipe depth Hs is preferably in the range of 0.35 to 0.65 times the groove depth D3 of the main groove 3 from the viewpoint of exposing the cavity 10 after the middle stage of wear.

Further, in this example, the land portion 4 has a first land portion having a muffling means (middle land portion 4M in this example) and a second land portion having no muffling means 5 (center land portion in this example). It is divided into 4C and shoulder land 4S). In the tread rubber, it is preferable to set the complex elastic modulus E ^* 1 of the rubber in the first land portion to be larger than the complex elastic modulus E ^* 2 of the rubber in the second land portion. When the tread rubber is formed of a plurality of layers (for example, cap rubber and base rubber), the complex elastic moduli E ^* 1 and E ^* 2 are complex in the outermost layer rubber (for example, cap rubber) in the tire radial direction. Defined as elastic modulus.

As a result, it is possible to suppress a decrease in the rigidity of the first land portion without being affected by the size of the resonator H, the number of formations, and the like. For that purpose, the difference ΔE ^* between the complex elastic modulus E ^* 1 and the complex elastic modulus E ^* 2 is preferably 5.0 MPa or more. The upper limit of the difference ΔE ^* is preferably 20 MPa or less, and when it exceeds 20 MPa, the noise reduction effect decreases.

The complex elastic modulus E ^* is a value measured using a “viscoelastic spectrometer” under the conditions shown below in accordance with the provisions of JIS-K6394.
・ Initial distortion (10%),
・ Amplitude (± 1%),
・ Frequency (10Hz),
・ Deformation mode (tension),
-Measurement temperature (70 ° C).

Here, the volume V of the cavity portion 10, the cross-sectional area S of the communication portion 11, and the length L of the communication portion 11 are appropriately set in order to obtain a desired natural frequency f. However, since the resonator H needs to be formed inside the land portion 4, there are restrictions on the volume V, the cross-sectional area S, and the length L.

For example, if the volume V of the cavity 10 is too large, the rigidity of the tread portion 2 is lowered, problems occur in the demolding property after vulcanization, and if it is too small, the sound deadening effect is lowered. Further, if the cross-sectional area S of the communicating portion 11 is too large, the adhesive friction when the air K1 of the communicating portion 11 vibrates becomes small, and the muffling effect is reduced. On the contrary, if the cross-sectional area S is too small, it does not function sufficiently as the resonator H. Further, if the length L of the communication portion 11 is too long, the rigidity and the muffling effect are lowered, and conversely, if the length L is too short, the muffling effect is lowered. From this point of view, the volume V of the cavity 10 is preferably in the range of 20 to 4000 mm ³ . The cross-sectional area S of the communication portion 11 is preferably in the range of 1.5 to 20 mm ² . Further, the length L of the communication portion 11 is preferably in the range of 2 to 50 mm.

FIG. 6B shows another embodiment of the communication unit 11. The communication portion 11 of this example is formed from a fine groove-shaped communication groove 14 provided on the tread surface 4s. The communication groove 14 is a straight groove and extends from the main groove 3 (center main groove 3C in this example) to the first sipe 8 with a substantially constant groove width. The cross-sectional area S perpendicular to the length direction of the communication groove 14 is smaller than the cross-sectional area S0 perpendicular to the length direction of the cavity 10. The communication groove 14 has a groove depth deeper than that of the first sipe 8, and therefore conducts the main groove 3 (center main groove 3C in this example) and the cavity 10 on the groove bottom side. The communication groove 14 has a narrow groove shape wider than that of the first sipe 8, and the gap between the groove wall surfaces is not blocked at the time of touchdown, and a gap is secured between the groove wall surfaces. The groove width W14 of the communication groove 14 is not particularly limited, but is preferably 3.0 mm or less, more preferably 2.0 mm or less.

FIG. 7 shows another embodiment of the tire 1. In the tire 1 of this example, each land portion 4 is divided into a plurality of blocks 7 arranged in the tire circumferential direction by a transverse groove 6 crossing the land portion 4. Then, for example, the muffling means 5 is formed in at least one of the blocks 7 arranged in the middle land portion 4M. In this example, the cavity 10 and the first sipe 8 are inclined at an angle of, for example, 45 to 90 degrees with respect to the tire circumferential direction line. Further, the first sipe 8 crosses the middle land portion 4M (block 7), and both ends thereof are opened by main grooves 3C and 3S. Reference numeral 15 in FIG. 1 is a sipe, which is formed on the center land portion 4C, the middle land portion 4M, and the shoulder land portion 4E, and cooperates with the first sipe 8 to provide the wet performance and the on-ice performance of the tire 1. To improve. As the sipe 15, a three-dimensional sipe 12 can be preferably adopted, but a two-dimensional sipe extending linearly in the depth direction or a flat sipe can also be adopted.

In this example, the muffling means 5 is provided in the middle land portion 4M, but the present invention is not limited to this, and the muffling means 5 can be provided in any one or more land portions 4.

Although the particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified into various embodiments.

A pneumatic tire (215 / 60R16) having the tread pattern shown in FIG. 1 and equipped with the muffling means shown in Table 1 was prototyped, and the noise performance outside the vehicle and the wet performance were tested. Each tire has substantially the same specifications except those shown in Table 1.

(1) External noise performance:
Install new tires on all wheels of the vehicle under the following conditions, run the test course (ISO road surface) at a speed of 80 km / h with the engine off, and leave 7.5 m from the center line and from the road surface. The maximum level dB (A) of passing noise was measured with a microphone installed at a height of 1.2 m. The results are displayed with a score of 100 for Comparative Example 1, and the larger the value, the lower the noise and the better the outside noise performance.
Rim: 16x6J
Internal pressure: 230kPa
Vehicle: Passenger car (displacement 1800cc, FF vehicle)

(2) Wet performance:
Using an inside drum tester, the rate of occurrence of the hydroplaning phenomenon was measured when the tire was run under the following conditions when the tire was worn at 50%. The results are displayed with a score of 100 for Comparative Example 1, and the larger the value, the better the wet performance.
Rim: 16x6J
Internal pressure: 230kPa
Load: 4.8kN
Water depth: Water depth 5.0 mm

As shown in the table, it can be confirmed that the tires of the examples can improve the noise performance outside the vehicle by reducing the air column resonance sound caused by the main groove. Further, it can be confirmed that the tire of the embodiment can improve the wet performance after 50% wear.

1 Tire 2 Tread part 3 Main groove 4 Land part 5 Silent means 8 1st sipe 9 2nd sipe 10 Cavity part 11 Communication part 12 3D sipe 13 Communication hole 14 Communication groove C Tire equator

Claims (8)

A tire having a tread portion having a main groove extending in the circumferential direction of the tire and a plurality of land portions classified by the main groove.
At least one land area
A cavity that is substantially sealed inside the land portion and whose both ends in the length direction are interrupted inside the land portion.
It is equipped with a sound deadening means having a communication portion that communicates the cavity portion and the main groove.
The muffling means has a first sipe extending from the cavity to the tread of the land.
The first sipe extends along the length direction of the cavity.
The length direction is the tire circumferential direction.
tire. The tire according to claim 1, wherein the muffling means is one or more arranged within a ground contact range where the tread portion is in contact with the road surface. The communication portion communicates the cavity portion with the main groove through the inside of the land portion, and the cross-sectional area perpendicular to the length direction is smaller than the cross-sectional area perpendicular to the length direction of the cavity portion. The tire according to claim 1 or 2, further comprising a small hole-shaped communication hole, and the sound deadening means having a second sipe extending from the communication hole to the tread surface of the land portion. The tire according to any one of claims 1 to 3, wherein the communication portion is composed of a fine groove-shaped communication groove provided on the tread surface of the land portion. The volume V (mm ³ ) of the cavity portion, the cross-sectional area S (mm ² ) perpendicular to the length direction of the communication portion, and the length L (mm) of the communication portion have the following formula (1). The tire according to any one of claims 1 to 4 to be satisfied.
5.0 × 10 ^-5 ≦ S / (V × L) ≦ 3.0 × 10 ^-3 --- (1) The volume V of the cavity is 20 to 4000 mm. ³ The tire according to any one of claims 1 to 5. The cross-sectional area S of the communication portion is 1.5 to 20 mm. ² The tire according to any one of claims 1 to 6, which is in the range of. The tire according to any one of claims 1 to 7, wherein the length L of the communication portion is in the range of 2 to 50 mm.

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