JP7365290B2 - tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to tires.

BACKGROUND ART Conventionally, there is a tire having a plurality of circumferential main grooves on a tread surface (for example, Patent Document 1).

JP 2016-7973 Publication

Conventional tires such as those described above generally have a deep circumferential main groove, and therefore a thick tread rubber. Therefore, it is not preferable from the viewpoint of tire weight reduction and rolling resistance.
The inventors of the present invention have found that if the depth of the circumferential main groove is made shallower, and the thickness of the tread rubber is made thinner, the weight of the tire and the rolling resistance can be reduced, but the noise will be increased. We have newly focused on this tendency and have come up with the present invention.

An object of the present invention is to provide a tire that can suppress an increase in noise while reducing the groove depth of a circumferential main groove.

The tire of the present invention is
A tire comprising a first circumferential main groove and a second circumferential main groove on the tread surface,
A resonator is formed in an intermediate land section defined between the first circumferential main groove and the second circumferential main groove,
The resonator has a minor groove that terminates at both ends within the intermediate land portion,
The groove depth D1 of the first circumferential main groove and the second circumferential main groove is 50% or less of the groove width W2 of the first circumferential main groove and the second circumferential main groove, respectively,
A groove depth D3 of the minor groove of the resonator is 70% or more of a groove depth D1 of the first circumferential main groove.
According to the tire of the present invention, increase in noise can be suppressed while reducing the groove depth of the circumferential main groove.

In the tire of the present invention,
It is preferable that the groove depth D1 of the first circumferential main groove and the second circumferential main groove are each 6.5 mm or less.
Thereby, the groove depth of the circumferential main groove can be made shallower.

In the tire of the present invention,
The groove depth D3 of the sub-groove of the resonator is preferably 5.5 mm or more.
Thereby, noise can be further suppressed.

In the tire of the present invention,
The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The groove depth D2 of the branch groove of the resonator is preferably 70% or more of the groove depth D1 of the first circumferential main groove.
This can reduce wear.

In the tire of the present invention,
The groove width W3 of the sub-groove of the resonator is preferably 60% or less of the groove depth D3 of the sub-groove.
Thereby, reduction in rigidity due to the provision of the resonator can be suppressed.

In the tire of the present invention,
The groove width W2 of the first circumferential main groove and the second circumferential main groove is preferably 5 to 15% of the ground contact width TW of the tire, respectively.
Thereby, drainage performance can be improved.

In the tire of the present invention,
The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
Preferably, the branch groove of the resonator has an acute inclination angle θ1 of 20 to 60 degrees with respect to the tire width direction at the end thereof that opens into the first circumferential main groove.
Thereby, it becomes possible to ensure sufficient rigidity of the block portion partitioned between the branch groove and the first circumferential main groove, and to ensure a sufficient length of the branch groove.

In the tire of the present invention,
The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
An acute inclination angle θ3 with respect to the tire width direction at the end of the sub-groove of the resonator that is far from the first circumferential main groove is equal to the inclination angle θ3 of the sub-groove of the resonator in the first circumferential direction. It is preferable that the inclination angle θ1 on the acute angle side with respect to the tire width direction is larger than the inclination angle θ1 at the end on the side opening into the main groove.
This makes it possible to increase the length of the sub-groove while ensuring sufficient rigidity of the block section defined between the branch groove and the first circumferential main groove.

In the tire of the present invention,
The minor groove of the resonator is
a first minor groove portion extending toward the first circumferential side of the tire while gradually moving away from the first circumferential major groove;
a second minor groove portion that is continuous from an end of the first minor groove portion closer to the first circumferential main groove and extends toward a second side in the tire circumferential direction;
has
An acute inclination angle θ6 with respect to the tire width direction at the end of the second sub-groove connected to the first sub-groove is defined as an inclination angle θ6 on the acute side with respect to the tire width direction at the end of the second sub-groove connected to the second sub-groove. It is preferable that the inclination angle θ4 on the acute angle side with respect to the tire width direction is larger than the inclination angle θ4 at the end of the tire width direction.
This makes it possible to increase the overall length of the sub-groove.

In the tire of the present invention,
Preferably, the first sub-groove portion of the sub-groove of the resonator has an inclination angle on an acute side with respect to the tire width direction that gradually increases as the distance from the first circumferential main groove increases.
This makes it possible to increase the length of the sub-groove while ensuring sufficient rigidity of the block section defined between the branch groove and the first circumferential main groove.

In the tire of the present invention,
Preferably, the length L1 of the first sub-groove of the sub-groove of the resonator is 2.0 to 7.0 times the length L2 of the second sub-groove of the sub-groove of the resonator. It is.
This makes it possible to increase the overall length of the sub-groove.

In the tire of the present invention,
Preferably, the branch groove of the resonator is connected to a connecting portion between the first sub-groove and the second sub-groove in the sub-groove of the resonator.
Thereby, noise can be further suppressed.

In the tire of the present invention,
The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
It is preferable that the pitch interval P1 of the branch grooves of the resonator in the tire circumferential direction is 2.5 to 5.0 times the groove depth D2 of the branch grooves.
Thereby, wear can be suppressed while suppressing reduction in rigidity due to the provision of the resonator.

In the tire of the present invention,
The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The branch groove of the resonator is
a tread side sipe portion that opens in the tread surface and extends inward in the tire radial direction;
a tunnel portion that continuously extends inward in the tire radial direction from the tread side sipe portion and has a groove width larger than that of the tread side sipe portion;
It is preferable to have the following.
Thereby, it is possible to suppress reduction in rigidity due to the provision of the resonator while suppressing noise.

In the tire of the present invention,
The resonator may be arranged only on one side with respect to the tire equatorial plane.

In the tire of the present invention,
The width W1 of the intermediate land portion is preferably 30 to 50% of the ground contact width TW of the tire.
Thereby, reduction in rigidity due to the provision of the resonator can be suppressed.

In the tire of the present invention,
The negative ratio of the tread surface is preferably 25 to 30%.
Thereby, sufficient drainage performance can be ensured while suppressing a reduction in rigidity due to the provision of the resonator.

In the tire of the present invention,
The maximum value of the thickness T1 of the tread rubber is preferably 8 mm or less.
This makes it possible to further reduce tire weight and rolling resistance.

In the tire of the present invention,
The intermediate land portion is located on the tire equatorial plane,
A narrow groove may be provided in the intermediate land portion on the tire equatorial plane.
In this case, drainage performance can be improved.

In the tire of the present invention,
The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The groove wall of the first circumferential main groove is curved convexly toward the inner side in the tire radial direction and the outer side in the groove width direction,
Preferably, the branch groove of the resonator extends to the groove wall of the first circumferential main groove.
Thereby, noise can be further suppressed.

According to the present invention, it is possible to provide a tire that can suppress an increase in noise while reducing the groove depth of the circumferential main groove.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a developed view showing a tread surface of a tire according to an embodiment of the present invention in a flat state. 2 is a partially enlarged view of FIG. 1. FIG. FIG. 2 is a cross-sectional view in the width direction of the tire, showing a part of the tire in FIG. 1 in a cross section taken along line AA in FIG. 1; FIG. 2 is an enlarged perspective view of a portion of the tire shown in FIG. 1; FIG. 2 is a developed view showing a tread surface of a tire according to a first modification of the present invention when it is developed on a plane. FIG. 7 is a developed view showing a tread surface of a tire according to a second modification of the present invention in a state when it is developed on a plane.

The tire according to the present invention can be used as any type of pneumatic tire, but is preferably used as a pneumatic tire for passenger cars.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a tire according to the present invention will be described by way of example with reference to the drawings. Common components in each figure are given the same reference numerals.

The tires of each example described in this specification include a tread portion 90 (FIG. 3) and a pair of shoulder portions (not shown) extending inward in the tire radial direction from both ends of the tread portion 90 in the tire width direction. and a pair of bead portions (not shown) that continue from the pair of shoulder portions inward in the tire radial direction.
Each example tire described herein may include any internal configuration. Each example tire described in this specification includes, for example, a pair of bead cores (not shown) provided in a pair of bead portions, and a pair of bead fillers (not shown) located outside the bead core in the tire radial direction. , a carcass 70 (FIG. 3), a belt 60 (FIG. 3), and tread rubber 80 (FIG. 3). The carcass 70 extends in a toroidal shape between a pair of bead cores. The carcass 70 includes at least one layer (one layer in the illustrated example) of carcass ply. The carcass ply of the carcass 70 may have a structure in which, for example, a cord made of steel or organic fiber is coated with rubber. The carcass 70 includes, for example, a main body that extends in a toroidal manner between a pair of bead cores, and a main body extending from the innermost end in the tire radial direction of the main body on each side with respect to the tire equatorial plane CL to the outside in the tire width direction around the bead cores. A pair of folded portions folded back toward. The belt 60 is arranged in the tread portion 90 on the outer side in the tire radial direction than the crown area of the carcass 70 (FIG. 3). The belt 60 consists of at least one belt layer 61 (two layers in the illustrated example). The belt layer 61 can have a structure in which, for example, a cord made of steel or organic fiber is coated with rubber. The tread rubber 80 is arranged on the outer side of the belt 60 in the tire radial direction.

Hereinafter, a tire according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.
FIG. 1 is a developed view showing a tread surface 1 of a tire according to an embodiment of the present invention when it is developed on a plane. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 3 is a cross-sectional view in the tire width direction showing a part of the tire shown in FIG. 1 in a cross section taken along line AA in FIG. FIG. 4 is an enlarged perspective view of a portion of the tire shown in FIG. 1. FIG.

The tire in the example of FIG. 1 is a tire with a specified mounting direction on the vehicle. In FIG. 1, the arrow OUT direction indicates the outer side in the vehicle width direction (hereinafter referred to as the "vehicle mounted outer side") when this tire is mounted on the vehicle, and the arrow IN direction indicates the outer direction in the vehicle width direction when this tire is mounted on the vehicle. Indicates the inside direction in the width direction of the vehicle (hereinafter referred to as "vehicle mounting inside"). The tread surface 1 of this tire is provided with a tread pattern that is asymmetrical with respect to the tire equatorial plane CL.
However, the tires in each example described in this specification may be tires for which the mounting direction on the vehicle is not specified. Further, the tread pattern of each example tire described in this specification may be asymmetrical with respect to the tire equatorial plane CL, or may be symmetrical with respect to the tire equatorial plane CL.
In this specification, for convenience, the upper side of FIG. 1 is referred to as the "tire circumferential first side (CD1)," and the lower side of FIG. 1 is referred to as the "tire circumferential second side (CD2)."

In this specification, "tread surface (1)" is the part that comes into contact with the road surface when a tire assembled to a rim and filled with a predetermined internal pressure is rolled under a maximum load. , refers to the outer circumferential surface of the tire.
In this specification, "ground contact edge (TE1, TE2)" means the end of the tread surface (1) in the tire width direction.
Here, "rim" refers to the industrial standard that is valid in the region where tires are produced and used. Standard rims in applicable sizes (ETRTO's STANDARDS MANUAL, Measuring Rim In TRA's YEAR BOOK, it refers to Design Rim) (i.e., the above "rim" includes not only the current size but also sizes that may be included in the above industrial standard in the future. "Sizes to be listed in the future" An example of this is the size listed as "FUTURE DEVELOPMENTS" in ETRTO's STANDARDS MANUAL 2013 edition.) However, if the size is not listed in the above industrial standards, it corresponds to the tire bead width. The width of the rim.
In addition, "prescribed internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating, as described in the above JATMA YEAR BOOK, etc., and as stated in the above industrial standards. In the case of a size without a tire, it refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle to which the tire is installed.
The term "maximum load" refers to the load corresponding to the maximum load capacity described above.
Note that the air here can also be replaced with an inert gas such as nitrogen gas.

In this specification, unless otherwise specified, the dimensions of each element such as a groove or a land portion, the ground contact width (TW), etc. are measured in the "reference state" described below.
In this specification, the term "reference state" refers to a state in which the tire is assembled to the rim, filled with the above-mentioned predetermined internal pressure, and left unloaded. Here, the dimensions of each element such as grooves and land portions in the tread surface, the ground contact width (TW), etc. are measured on the developed view of the tread surface.

The tires of each example described in this specification are equipped with at least two (only two in the example of FIG. 1) circumferential main grooves 10 on the tread surface 1, as in the example of FIG. The tires of each example described in this specification include at least a first circumferential main groove 11 and a second circumferential main groove 12 as the circumferential main groove 10. One or more intermediate land portions 20 are defined between the at least two circumferential main grooves 10. That is, an intermediate land portion 20 is defined between the first circumferential main groove 11 and the second circumferential main groove 12.
In the example of FIG. 1, a first end land portion 30 is defined between the first circumferential main groove 11 and the first ground contact end TE1. In the example of FIG. 1, a second end land portion 40 is defined between the second circumferential main groove 12 and the second ground contact end TE2.
The intermediate land portion 20, the first end land portion 30, and the second end land portion 40 are not divided in the tire circumferential direction by lateral grooves (excluding sipes), and are continuous throughout the tire circumferential direction. In other words, it is configured as a rib-like land portion.
In the example of FIG. 1, the first circumferential main groove 11, the first ground contact edge TE1, and the first end land portion 30 are located on the vehicle mounting outer side (OUT side) with respect to the tire equatorial plane CL, The second circumferential main groove 12, the second ground contact edge TE2, and the second end land portion 40 are located on the vehicle mounting inner side (IN side) with respect to the tire equatorial plane CL, and the intermediate land portion 20 is located on the tire equatorial plane CL. It is located on the equatorial plane CL. However, the first ground contact end TE1 and the first end land portion 30 are located on the inside (IN side) of the tire with respect to the tire equatorial plane CL, and the second ground contact end TE2 and the second end land portion 40 are located on the outside of the vehicle installation side. It may be located on the OUT side. Further, the first circumferential main groove 11 and the second circumferential main groove 12 may be located on either side with respect to the tire equatorial plane CL. For example, the second circumferential main groove 12 may be located on either side of the tire equatorial plane CL. The first circumferential main groove 11 may be located on the vehicle mounting outer side (OUT side) with respect to the tire equatorial plane CL, and the first circumferential main groove 11 may be located on the vehicle mounting inner side (IN side) with respect to the tire equatorial plane CL. Further, the first circumferential main groove 11 and the second circumferential main groove 12 may be located on opposite sides of the tire equatorial plane CL as in the example of FIG. They may be located on the same side with respect to CL. Further, the intermediate land portion 20 may be located on the tire equatorial plane CL as in the example of FIG. 1, or may not be located on the tire equatorial plane CL.

In the tires of each example described in this specification, the groove depth of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) provided in the tread surface 1 is The maximum value of the width D1 (FIG. 3) is 50 of the groove width W2 (FIG. 1) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove). % or less.
As described above, in the tires of each example described in this specification, each circumferential main groove 10 provided in the tread surface 1 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove ) groove depth D1 (FIG. 3) is shallower than that of conventional tires.

In each example described in this specification, as shown in FIGS. 1 to 4, the intermediate land portion 20 defined between the first circumferential main groove 11 and the second circumferential main groove 12 includes: A plurality of resonators 21 are formed. The resonator 21 has a sub-groove 211. Preferably, the resonator 21 further includes a branch groove 212. Both ends of the sub-groove 211 terminate within the intermediate land portion 20 . The branch groove 212 extends so as to connect the sub-groove 211 and the first circumferential main groove 11, and has a smaller groove cross-sectional area than the sub-groove 211.
Here, the "groove cross-sectional area" of the branch groove 212, the sub-groove 211, etc. is measured along a virtual plane perpendicular to the groove width center line of each groove in the above-mentioned "reference state".

In each example described in this specification, as described above, each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) provided in the tread surface 1 The maximum value of the groove depth D1 (Fig. 3) is the groove width W2 (Fig. 1) of each circumferential main groove 10 (in the example of Fig. 1, the first circumferential main groove and the second circumferential main groove). ), that is, it is shallower than conventional tires. As a result, the thickness T1 (FIG. 3) of the tread rubber 80 of the tire can be made thinner than that of conventional tires. This makes it possible to reduce the weight of the tire and reduce the rolling resistance of the tire. In addition, in recent years, with the shift to eco-friendly cars such as electric vehicles (EVs) and plug-in hybrid cars (PHEVs), there has been an increasing demand for lighter vehicle parts, and there has also been an increasing demand for lighter tires. be. Further, there is a growing demand for lower rolling resistance, as the rolling resistance of tires is becoming stricter under environmental regulations such as R117 in Europe. The tires of each example described in this specification can meet these demands.
On the other hand, simply making each circumferential main groove 10 shallower as described above and, in turn, reducing the thickness T1 (FIG. 3) of the tread rubber 80, increases the rigidity of the tire and makes it easier for vibrations to be transmitted. When rolling, the input from the road surface becomes stronger, and noise (particularly passing noise) tends to be generated more easily. Therefore, in the tires of each example described in this specification, as described above, the resonator 21 is provided in the intermediate land portion 20 defined between the first circumferential main groove 11 and the second circumferential main groove 12. is formed. By forming the resonator 21, when the tire is rolling, the air flowing through the first circumferential main groove 11 flows into the resonator 21, thereby dispersing the frequency and reducing noise. Thereby, it is possible to suppress an increase in noise (passing noise) that may be caused by making each circumferential main groove 10 shallower. Note that tire noise regulations are becoming stricter under environmental regulations such as R117 in Europe, and demands for noise reduction are also increasing. The tires of each example described in this specification can meet such demands.
As described above, according to the tires of each example described in the present invention, it is possible to suppress an increase in noise while reducing the groove depth of the circumferential main groove.

Hereinafter, preferred configurations, modifications, etc. of the tires of each example described in this specification will be described.

In the tires of each example described in this specification, the maximum groove depth D1 (FIG. 3) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) It is more preferable that the value is 45% or less of the groove width W2 (FIG. 1) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove). be. Thereby, the groove depth of the circumferential main groove can be made shallower. As a result, the thickness T1 (FIG. 3) of the tread rubber 80 can be made thinner, making it easier to reduce the weight of the tire and reduce the rolling resistance.
Similarly, from the perspective of reducing the groove depth of the circumferential main groove, the groove depth D1 ( The maximum values in FIG. 3) are preferably 6.5 mm or less, and more preferably 6.0 mm or less.
Similarly, from the perspective of reducing the groove depth of the circumferential main groove, the groove depth D1 ( The maximum values in FIG. 3) are preferably 80% or less, and more preferably 75% or less, of the thickness T1 (FIG. 3) of the tread rubber 80, respectively.
On the other hand, in the tires of each example described in this specification, the groove depth D1 (FIG. 3) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) The minimum value of each is preferably 20% or more of the groove width W2 (FIG. 1) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove). and more preferably 25% or more. Thereby, drainage performance can be improved.
Similarly, from the viewpoint of drainage performance, in the tires of each example described in this specification, the grooves of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) The minimum value of the depth D1 (FIG. 3) is preferably 5.0 mm or more, and more preferably 5.5 mm or more.
Similarly, from the viewpoint of drainage performance, the minimum value of the groove depth D1 (FIG. 3) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) is In each case, the thickness is preferably 65% or more, and more preferably 75% or more of the thickness T1 (FIG. 3) of the tread rubber 80.
Note that the groove depth D1 of the circumferential main groove 10 may be constant along the tire circumferential direction, or may vary along the tire circumferential direction.
Here, the "maximum value of the groove depth (D1) of the circumferential main groove (10)" refers to the groove depth (D1) at the portion where the groove depth (D1) of the circumferential main groove (10) is maximum. ). In addition, the "minimum value of the groove depth (D1) of the circumferential main groove (10)" refers to the groove depth (D1) at the portion where the groove depth (D1) of the circumferential main groove (10) is the minimum. refers to

In the tires of each example described in this specification, the groove width W2 (FIG. 1) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) is , it is suitable that it is 5% or more of the ground contact width TW of the tire. Thereby, drainage performance can be improved.
Similarly, from the viewpoint of drainage, the groove width W2 (Fig. 1) of each circumferential main groove 10 (in the example of Fig. 1, the first circumferential main groove and the second circumferential main groove) is 10 mm or more. It is preferable.
On the other hand, in the tires of each example described in this specification, the groove width W2 (FIG. 1) of each circumferential main groove 10 (in the example of FIG. 1, the first circumferential main groove and the second circumferential main groove) is , each is suitably 15% or less of the ground contact width TW of the tire. Thereby, sufficient rigidity can be ensured.
Similarly, from the viewpoint of rigidity, the groove width W2 (Fig. 1) of each circumferential main groove 10 (in the example of Fig. 1, the first circumferential main groove and the second circumferential main groove) is 20 mm or less. It is preferable if there is one.
Note that these ranges of the groove width W2 are particularly suitable when the number of circumferential main grooves 10 provided in the tread surface 1 is two.
In this specification, "tread width (TW)" means a value measured along the tread surface 1 of the distance in the tire width direction between a pair of ground contact edges (TE1, TE2).

In each tire example described in this specification, the maximum value of the thickness T1 (FIG. 3) of the tread rubber 80 is preferably 8 mm or less. This makes it possible to reduce tire weight and rolling resistance.
Similarly, from the viewpoint of weight reduction and rolling resistance, it is preferable that the maximum value of the thickness T1 (FIG. 3) of the tread rubber 80 is 70% or less of the maximum value of the gauge T2 (FIG. 3) of the tread portion 90. It is.
On the other hand, in the tires of each example described in this specification, the maximum value of the thickness T1 (FIG. 3) of the tread rubber 80 is preferably 6 mm or more. This improves the steering stability and ride comfort of the tire.
Similarly, from the viewpoint of handling stability and ride comfort, the maximum value of the thickness T1 (FIG. 3) of the tread rubber 80 should be 50% or more of the maximum value of the gauge T2 (FIG. 3) of the tread portion 90. , is suitable.
Here, "the maximum value of the thickness (T1) of the tread rubber (80)" refers to the thickness (T1) of the portion where the thickness (T1) of the tread rubber (80) is maximum. Moreover, "the maximum value of the gauge (T2) of the tread part (90)" refers to the gauge (T2) at the part where the gauge (T2) of the tread part (90) is maximum.

In each tire example described in this specification, the maximum value of the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 is 80% of the maximum value of the groove depth D3 (FIG. 3) of the sub-groove 211. It is preferable that it is below, and more preferable that it is 60% or less of the maximum value of the groove depth D3 (FIG. 3) of the sub-groove 211. As described above, by providing the resonator 21, it is possible to suppress an increase in noise that may be caused by making the circumferential main groove 10 shallower. By narrowing the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 in this way, the rigidity of the tread portion 90 (particularly the intermediate land portion 20) can be increased accordingly, so that the resonator 21 can be The reduction in rigidity of the tread portion 90 (particularly the intermediate land portion 20) that may occur due to the provision of this structure can be suppressed.
Similarly, from the viewpoint of rigidity, the maximum value of the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 is preferably 3.0 mm or less.
Similarly, from the viewpoint of rigidity, the maximum value of the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 is 80% of the maximum value of the groove depth D1 (FIG. 3) of the first circumferential main groove 11. It is preferable that it is below, and more preferable that it is 60% or less of the maximum value of the groove depth D1 (FIG. 3) of the first circumferential main groove 11.
On the other hand, in the tires of each example described in this specification, the maximum value of the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 is the maximum value of the groove depth D3 (FIG. 3) of the sub-groove 211. It is suitable that it is 15% or more. Thereby, the noise reduction performance of the resonator 21 can be improved.
Similarly, from the viewpoint of noise reduction performance, the maximum value of the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 is preferably 1.0 mm or more.
Similarly, from the perspective of noise reduction performance, the maximum value of the groove width W3 (FIG. 2) of the sub-groove 211 of the resonator 21 is the maximum value of the groove depth D1 (FIG. 3) of the first circumferential main groove 11. It is suitable that it is 15% or more.
Note that the groove width W3 of the sub-groove 211 may vary along the extending direction of the sub-groove 211 as in the example of FIG. 2, or may be constant along the extending direction of the sub-groove 211. .
Here, the "maximum value of the groove width (W3) of the sub-groove (211)" refers to the groove width (W3) at the portion where the groove width (W3) of the sub-groove (211) is maximum.
The groove width W3 of the sub-groove 211 is measured perpendicularly to the groove width center line 211c of the sub-groove 211.

In the tires of each example described in this specification, the minimum value of the groove depth D3 (FIG. 3) of the sub-groove 211 of the resonator 21 is preferably 5.0 mm or more, and 5.5 mm or more. It is more preferable if there is one. In this way, by increasing the groove depth D3 of the sub-groove 211, the volume of the sub-groove 211 can be increased, and as a result, the noise reduction performance of the resonator 21 can be improved (as a result, an increase in noise can be suppressed). This is particularly suitable when narrowing the groove width W3 (FIG. 2) of the sub-groove 211 as described above.
Similarly, from the viewpoint of noise reduction performance, the minimum value of the groove depth D3 (FIG. 3) of the sub-groove 211 of the resonator 21 is the maximum value of the groove depth D1 (FIG. 3) of the first circumferential main groove 11. It is suitable that it is 70% or more.
On the other hand, in the tires of each example described in this specification, the maximum value of the groove depth D3 (FIG. 3) of the sub-groove 211 of the resonator 21 is preferably 6.5 mm or less. Thereby, reduction in rigidity of the tread portion 90 (particularly the intermediate land portion 20) that may occur due to the provision of the resonator 21 can be suppressed.
Similarly, from the viewpoint of rigidity, the maximum value of the groove depth D3 (FIG. 3) of the minor groove 211 of the resonator 21 is 100% of the maximum value of the groove depth D1 (FIG. 3) of the first circumferential main groove 11. % or less is suitable.
Note that the groove depth D3 of the sub-groove 211 may be constant along the extending direction of the sub-groove 211, or may vary along the extending direction of the sub-groove 211.
Here, "the minimum value of the groove depth (D3) of the sub-groove (211)" refers to the groove depth (D3) at the portion where the groove depth (D3) of the sub-groove (211) is the minimum. Moreover, "the maximum value of the groove depth (D3) of the sub-groove (211)" refers to the groove depth (D3) at the portion where the groove depth (D3) of the sub-groove (211) is maximum. Moreover, "the extending direction of the minor groove (211)" is the extending direction of the groove width center line (211c) of the minor groove (211).

In each tire example described in this specification, the minimum value of the groove depth D2 (FIG. 3) of the branch groove 212 of the resonator 21 is 70% or more of the groove depth D1 of the first circumferential main groove. And it is suitable. In this way, by increasing the groove depth D2 of the branch grooves 212, wear of the tread portion 90 (particularly the block portion 20b of the intermediate land portion 20) can be reduced. Note that when the circumferential main groove 10 is made shallower and the thickness T1 of the tread rubber 80 is made thinner as described above, the rigidity of the tread portion 90 tends to increase. By increasing the depth D2, wear can be effectively reduced while ensuring sufficient rigidity.
On the other hand, in the tires of each example described in this specification, the maximum value of the groove depth D2 (FIG. 3) of the branch grooves 212 of the resonator 21 is 100% or less of the groove depth D1 of the first circumferential main groove. It is preferable. Thereby, rigidity can be improved.
Note that the groove depth D2 of the branch groove 212 may be constant along the extending direction of the branch groove 212, or may vary along the extending direction of the branch groove 212.
Here, "the minimum value of the groove depth (D2) of the branch groove (212)" refers to the groove depth (D2) at the portion where the groove depth (D2) of the branch groove (212) is the minimum. Moreover, "the maximum value of the groove depth (D2) of the branch groove (212)" refers to the groove depth (D2) at the portion where the groove depth (D2) of the branch groove (212) is maximum. Moreover, "the extending direction of the branch groove (212)" is the extending direction of the groove width center line of the branch groove (212).

In the tires of each example described in this specification, the sub-groove 211 of the resonator 21 gradually moves away from the first circumferential main groove 11 toward the first side CD1 in the tire circumferential direction, as in the example of FIG. The first sub-groove portion 2111 extends from the end closer to the first circumferential main groove 11 of both ends of the first sub-groove portion 2111 in the extending direction, and continues toward the second side CD2 in the tire circumferential direction. The second sub-groove portion 2112 may also be provided. In this case, the inclination angle θ6 (FIG. 2) on the acute angle side with respect to the tire width direction at the end of the second sub-groove 2112 connected to the first sub-groove 2111 is It is preferable that the inclination angle θ4 (FIG. 2) on the acute angle side with respect to the tire width direction at the end connected to the groove portion 2112 is larger. In this way, since the sub-groove 211 has the second sub-groove part 2112 in addition to the first sub-groove part 2111, it becomes possible to increase the overall length of the sub-groove 211, so that the sub-groove 211 The volume of the resonator 21 can be increased, and the noise reduction performance of the resonator 21 can be improved. Furthermore, the second sub-groove portion 2112 can reduce compression rigidity.
The second sub-groove portion 2112 preferably extends toward the second side CD2 in the tire circumferential direction while gradually approaching the first circumferential main groove 11, as in the example of FIG. However, the second minor groove portion 2112 may extend parallel to the first circumferential main groove 11 and toward the second side CD2 in the tire circumferential direction, or alternatively, the second minor groove portion 2112 may , may extend toward the tire circumferential second side CD2 while gradually moving away from the first circumferential main groove 11.
However, the sub-groove 211 may have only the first sub-groove part 2111 without having the second sub-groove part 2112.

In the tires of each example described in this specification, the inclination angle of the second sub-groove portion 2112 of the sub-groove 211 of the resonator 21 on the acute side with respect to the tire width direction at the end on the side connected to the first sub-groove portion 2111 θ6 (FIG. 2) is the inclination angle θ4 (FIG. 2) on the acute side with respect to the tire width direction at the end of the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 on the side connected to the second sub-groove portion 2112. It is preferable that it is 1.0 to 5.0 times as large.

In the tires of each example described in this specification, the inclination angle of the second sub-groove portion 2112 of the sub-groove 211 of the resonator 21 on the acute side with respect to the tire width direction at the end on the side that terminates within the intermediate land portion 20 θ5 (FIG. 2) is 0.9 to 1.1 of the inclination angle θ6 (FIG. 2) on the acute side with respect to the tire width direction at the end of the second minor groove portion 2112 that connects with the first minor groove portion 2111. It is suitable that it is twice as large.

In the tires of each example described in this specification, the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 has a groove width that increases as the groove width increases toward the first side CD1 in the tire circumferential direction, as in the example of FIG. It is preferable that it decreases gradually.
In each example tire described in this specification, the second sub-groove portion 2112 of the sub-groove 211 of the resonator 21 has a groove width that increases as it goes toward the second side CD2 in the tire circumferential direction, as in the example of FIG. It is preferable that it decreases gradually.

In each example of the tire described in this specification, the branch groove 212 of the resonator 21 has an end that opens to the first circumferential main groove 11 (more specifically, an end that opens to the intermediate land portion 20 and the first circumferential main groove It is preferable that the inclination angle θ1 (FIG. 2) on the acute side with respect to the tire width direction at the end located at the boundary with the main groove 11 is 20° or more. This ensures sufficient rigidity of the corner portion 20c of the block portion 20b that is partitioned between the branch groove 212 and the first circumferential main groove 11 in the intermediate land portion 20, and prevents blistering at the corner portion 20c. can be suppressed.
On the other hand, in the tires of each example described in this specification, the branch groove 212 of the resonator 21 has an acute angle of inclination θ1 ( 2) is preferably 60° or less, more preferably 45° or less. Thereby, it becomes possible to sufficiently secure the length L3 of the branch groove 212, and as a result, the noise reduction performance of the resonator 21 can be improved.

In the tires of each example described in this specification, the branch grooves 212 of the resonator 21 have an acute angle of inclination θ2 (FIG. 2 ) is preferably 20° or more.
On the other hand, in the tires of each example described in this specification, the branch grooves 212 of the resonator 21 have an acute angle of inclination θ2 ( 2) is preferably 60° or less, more preferably 45° or less.

In each tire example described in this specification, the branch grooves 212 of the resonator 21 may have a constant inclination angle on the acute side with respect to the tire width direction as in the example of FIG. 2, or may have a constant inclination angle along the tire width direction, or The inclination angle on the acute side with respect to the tire width direction may gradually increase as it gradually moves away from the first circumferential main groove 11.

In the tires of each example described in this specification, the inclination angle θ3 of the sub-groove 211 of the resonator 21 on the acute side with respect to the tire width direction at the end on the side far from the first circumferential main groove 11 (FIG. 2) is preferably larger than the inclination angle θ1 (FIG. 2) on the acute angle side with respect to the tire width direction at the end of the branch groove 212 of the resonator 21 that opens into the first circumferential main groove 11. .
As a result, while ensuring sufficient rigidity of the corner portion 20c of the block portion 20b partitioned between the branch groove 212 and the first circumferential main groove 11, It becomes possible to lengthen the length L1) of the first sub-groove portion 2111, and as a result, the noise reduction performance of the resonator 21 can be improved.
From the same viewpoint, the inclination angle θ3 (FIG. 2) on the acute side with respect to the tire width direction at the end of the sub-groove 211 of the resonator 21 on the side far from the first circumferential main groove 11 is preferably 45° or more. , and preferably 80° or less.
However, the inclination angle θ3 may be the same as the inclination angle θ1.

In each example tire described in this specification, the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 increases with respect to the tire width direction as it moves away from the first circumferential main groove 11, as in the example of FIG. It is preferable that the inclination angle on the acute side gradually increases.
As a result, while ensuring sufficient rigidity of the corner portion 20c of the block portion 20b partitioned between the branch groove 212 and the first circumferential main groove 11, It becomes possible to lengthen the length L1) of the first sub-groove portion 2111, and as a result, the noise reduction performance of the resonator 21 can be improved.
From a similar viewpoint, in the tires of each example described in this specification, the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 is convex toward the second side CD2 in the tire circumferential direction, as in the example of FIG. A curved shape is preferred.
However, the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 may have a constant inclination angle on the acute side with respect to the tire width direction, and may extend linearly along the tire width direction. Good too.

In the tires of each example described in this specification, the inclination angle of the acute angle side with respect to the tire width direction at the end of the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 on the side connected to the second sub-groove portion 2112 θ4 (FIG. 2) is 0.9 of the inclination angle θ2 (FIG. 2) on the acute side with respect to the tire width direction at the end of the branch groove 212 of the resonator 21 on the side away from the first circumferential main groove 11. It is preferable that it is ~1.1 times.

In the tires of each example described in this specification, the length L1 of the first sub-groove 2111 of the sub-groove 211 of the resonator 21 is equal to 2 of the length L2 of the second sub-groove 2112 of the sub-groove 211 of the resonator 21. It is suitable that it is .0 times or more. This makes it possible to increase the overall length of the sub-groove 211 (particularly the length L1 of the first sub-groove portion 2111), which in turn increases the volume of the sub-groove 211 and improves the noise reduction performance of the resonator 21. can be improved.
On the other hand, in the tires of each example described in this specification, the length L1 of the first sub-groove 2111 of the sub-groove 211 of the resonator 21 is the length L2 of the second sub-groove 2112 of the sub-groove 211 of the resonator 21. It is preferable that the length is 8.0 times or less, and more preferably 7.0 times or less the length L2 of the second sub-groove portion 2112 of the sub-groove 211 of the resonator 21. Thereby, reduction in the rigidity of the intermediate land portion 20 can be suppressed.
Note that the "length (L1) of the first sub-groove (2111)" is the length of the groove width center line (211c) of the first sub-groove (2111). Moreover, "the length (L2) of the second minor groove part (2112)" is the length of the groove width center line (211c) of the second minor groove part (2112).

In each tire example described in this specification, the length L1 of the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 is preferably 10 to 40% of the ground contact width TW of the tire.
This makes it possible to lengthen the length of the sub-groove 211 (particularly the length L1 of the first sub-groove portion 2111) and ensure rigidity.
From the same viewpoint, it is preferable that the length L1 of the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 is 15 to 40 mm.

In the tires of each example described in this specification, the length L1 of the first sub-groove portion 2111 of the sub-groove 211 of the resonator 21 is 1.0 to 5.0 of the length L3 of the branch groove 212 of the resonator 21. It is suitable that it is twice as large.
This makes it possible to ensure rigidity while further suppressing noise.
From the same viewpoint, the length L3 of the branch groove 212 of the resonator 21 is preferably 1 to 30% of the ground contact width TW of the tire.
From the same viewpoint, the length L3 of the branch groove 212 of the resonator 21 is preferably 3 to 40 mm.
Note that "the length (L3) of the branch groove (212)" is the length of the groove width center line of the branch groove (212).

In each tire example described in this specification, the volume of the sub-groove 211 of the resonator 21 is preferably 150 to 500 mm ³ .
This makes it possible to ensure rigidity while further suppressing noise.

In the tires of each example described in this specification, the branch groove 212 of the resonator 21 is connected to the first sub-groove 2111 and the second sub-groove 2112 in the sub-groove 211 of the resonator 21, as in the example of FIG. It is preferable that it is connected to the connecting part of.
Thereby, the air that has entered the branch grooves 212 from the first circumferential main groove 11 can smoothly enter the sub grooves 211, so that noise can be further suppressed.
However, the branch groove 212 of the resonator 21 may be connected to any part of the sub-groove 211 of the resonator 21.
Note that when the sub-groove 211 does not have the second sub-groove part 2112 and only has the first sub-groove part 2111, the branch groove 212 is located at the end of the first sub-groove part 2111 on the side closer to the first circumferential main groove 11. It is preferable if it is connected to the section.

In each example of the tire described in this specification, the branch groove 212 of the resonator 21 has a tread side sipe portion 2121 that opens in the tread surface 1 and extends inward in the tire radial direction, as shown in FIG. It is preferable to have a tunnel portion 2122 that extends continuously from the tread side sipe portion 2121 inward in the tire radial direction and has a groove width larger than that of the tread side sipe portion 2121.
Since the branch groove 212 has the tread side sipe portion 2121 on the outside in the tire radial direction, when the tire is rolling, the intermediate land portion 20 is partitioned between a pair of branch grooves 212 adjacent to each other in the tire circumferential direction. It is possible to suppress the block portion 20b from falling down. Further, since the branch groove 212 has the tunnel portion 2122 on the inner side in the tire radial direction, a passage of air to the resonator 21 can be ensured, and the noise reduction performance of the resonator 21 can be improved.
In this way, it is possible to suppress the reduction in rigidity due to the provision of the resonator while suppressing noise.
In addition, from the viewpoint of suppressing the collapse of the intermediate land portion 20 during rolling of the tire, the groove width (sipe width) of the tread side sipe portion 2121 is preferably 0.5 mm or less.
Similarly, from the viewpoint of suppressing the collapse of the intermediate land portion 20 when the tire rolls, the tread side sipe portion 2121 is designed to prevent the tire from falling when the tire is assembled to the rim, filled with the predetermined internal pressure, and loaded with the maximum load. It is preferable that the sipes be configured to close (a pair of mutually opposing sipe wall surfaces are in contact with each other at least in part) immediately under a load.
Further, from the viewpoint of ensuring an air passage to the resonator 21 when the tire is rolling, the groove width of the tunnel portion 2122 is preferably 0.8 mm or more.
Similarly, from the viewpoint of securing an air passage to the resonator 21 when the tire is rolling, the tunnel portion 2122 is designed to be used when the tire is assembled to the rim, filled with the predetermined internal pressure, and loaded with the maximum load. It is preferable that the sipe wall surface is configured so that it does not close (the pair of mutually opposing sipe wall surfaces do not come into contact with each other at any part) when directly under a load.
On the other hand, from the viewpoint of improving the noise reduction performance of the resonator 21, the groove width of the tunnel portion 2122 is preferably 1.5 mm or less.

In the tires of each example described in this specification, when the branch groove 212 of the resonator 21 has the tread side sipe portion 2121 and the tunnel portion 2122 as described above, the branch groove 212 is continuous from the tunnel portion 2122 toward the inside in the tire radial direction. It is preferable to further include a bottom side sipe portion 2123 that extends and has a groove width smaller than that of the tunnel portion 2122. Thereby, the noise reduction performance of the resonator 21 can be improved.
In this case, the groove width (sipe width) of the bottom side sipe portion 2123 is preferably the same as the groove width (sipe width) of the tread side sipe portion 2121.

In the tires of each example described in this specification, the groove walls 10a of each circumferential main groove 10 (in the illustrated example, the first circumferential main groove 11 and the second circumferential main groove 12) are as shown in FIGS. It is preferable that the groove be curved convexly toward the inner side in the tire radial direction and the outer side in the groove width direction, as in the example shown in No. 4. In other words, the groove walls 10a of each circumferential main groove 10 (in the illustrated example, the first circumferential main groove 11 and the second circumferential main groove 12) are preferably rounded.
Furthermore, it is preferable that the branch grooves 212 of the resonator 21 extend to the groove wall 10a of the first circumferential main groove 11, as shown in FIG. It is preferable that the branch groove 212 extends to the rounded groove wall 10a of the first circumferential main groove 11. In this case, a portion of the branch groove 212 extending along the groove wall 10a of the first circumferential main groove 11 constitutes an opening extension portion 212a.
By forming the branch grooves 212 deeply in this manner, wear of the tread portion 90 (particularly the block portion 20b of the intermediate land portion 20) can be reduced. Note that when the circumferential main groove 10 is made shallower as described above, and the thickness T1 of the tread rubber 80 is made thinner, the rigidity of the tread portion 90 tends to increase. By forming this, it is possible to effectively reduce wear while ensuring sufficient rigidity.
Further, the opening extension portion 212a allows the air in the first circumferential main groove 11 to easily enter the branch groove 212, thereby improving the noise reduction performance of the resonator 21. Therefore, noise can be further suppressed.
Here, "the outer side in the groove width direction" refers to the side that is farther away from the groove width center line.
In addition, in the cross section in the tire width direction (FIG. 3), the radius of curvature R of the groove wall 10a of each circumferential main groove 10 (in the example shown, the first circumferential main groove 11 and the second circumferential main groove 12) is: A range of 2.0 to 4.5 mm is suitable.
Further, as shown in the example of FIG. It is preferable that the groove of the first circumferential main groove 11 be located on the inner side in the tire radial direction than the center between the opening end surface to the tread surface 1 and the groove bottom of the first circumferential main groove 11. It is more suitable if it is located at the same position in the tire radial direction as the bottom.
Further, the branch groove 212 (specifically, the opening extension part 212a of the branch groove 212) terminates near the boundary between the groove wall 10a and the groove bottom of the first circumferential main groove 11, as shown in the example of FIG. It is preferable if you do so.

In the tires of each example described in this specification, the tunnel portion 2122 of the branch groove 212 of the resonator 21 is formed in the groove wall 10a (rounded) of the first circumferential main groove 11, as in the example shown in FIG. Preferably, it opens in the groove wall 10a).
This makes it easier for the air in the first circumferential main groove 11 to enter the branch grooves 212, thereby improving the noise reduction performance of the resonator 21. Therefore, noise can be further suppressed.

In each tire example described in this specification, the pitch interval P1 (FIG. 1) of the branch grooves 212 of the resonator 21 in the tire circumferential direction is 2.5 times the groove depth D2 (FIG. 3) of the branch grooves 212. The above is preferable. Thereby, reduction in rigidity due to the provision of the resonator 21 can be suppressed.
On the other hand, in the tires of each example described in this specification, the pitch interval P1 (FIG. 1) of the branch grooves 212 of the resonator 21 in the tire circumferential direction is 5.5 times larger than the groove depth D2 (FIG. 3) of the branch grooves 212. It is suitable that it is 0 times or less. Thereby, wear of the tread portion 90 (particularly the intermediate land portion 20) can be suppressed.

In each tire example described in this specification, the width W1 of the intermediate land portion 20 is preferably 30 to 50% of the ground contact width TW of the tire. Thereby, reduction in rigidity due to the provision of the resonator can be suppressed.
Similarly, in each tire example described in this specification, the width W1 of the intermediate land portion 20 is preferably 40 to 75 mm.

In the tires of each example described in this specification, the intermediate land portion 20 has an intermediate land portion sipe 22 which has one end opening into the second circumferential main groove 12 and the other end terminating within the intermediate land portion 20. It is preferable that a plurality of them are provided. Thereby, wear of the tread portion 90 (particularly the intermediate land portion 20) can be suppressed.
It is preferable that the intermediate land portion sipe 22 extends gradually toward the second circumferential side CD2 of the tire while moving away from the second circumferential main groove 12, as in the example of FIG.
Further, it is preferable that the intermediate land portion sipe 22 terminates before reaching the tire equatorial plane CL, as in the example shown in FIG.
The intermediate land sipe 22 closes immediately under the load when the tire is assembled to the rim, filled with the predetermined internal pressure, and the maximum load is applied (the pair of mutually opposing sipe wall surfaces contact each other at least in part). ) is preferable.
The pitch interval P2 (FIG. 1) of the intermediate land sipes 22 in the tire circumferential direction is 0.9 to 1.5 times the pitch interval P1 (FIG. 1) of the branch grooves 212 of the resonator 21 in the tire circumferential direction. It is preferable if there is one.

In each example tire described in this specification, the first end land portion 30 has a first end land portion that opens at one end to the first ground contact end TE1 and whose other end terminates within the first end land portion 30. It is preferable that a plurality of lug grooves 31 are provided. This makes it possible to improve drainage while ensuring rigidity.
It is preferable that the first end land lug groove 31 extends gradually toward the first side CD1 in the tire circumferential direction while moving away from the first ground contact end TE1, as in the example of FIG.
The groove width of the first end land portion lug groove 31 is preferably 1.5 to 4.5 mm, for example.
Note that the pitch interval P3 (FIG. 1) of the first end land lug grooves 31 in the tire circumferential direction is 0.4 to 1. It is suitable that it is 0 times.

In each example tire described in this specification, the second end land portion 40 has a second end land portion that has one end opening at the second ground contact end TE2 and the other end terminating within the second end land portion 40. It is preferable that a plurality of lug grooves 42 are provided. This makes it possible to improve drainage while ensuring rigidity.
It is preferable that the second end land lug groove 42 extends gradually toward the second side CD2 in the tire circumferential direction while moving away from the second ground contact end TE2, as in the example of FIG.
The groove width of the second end land lug groove 42 is preferably 1.5 to 4.5 mm, for example.
The pitch interval P4 (FIG. 1) of the second end land lug grooves 42 in the tire circumferential direction is 0.4 to 1. It is suitable that it is 0 times.

In the tires of each example described in this specification, when the second end land portion lug groove 42 is provided in the second end land portion 40 as described above, the second end land portion 42 is provided in the second end land portion 40. It is preferable that a plurality of connecting sipes 43 extending to connect the lug groove 42 and the second circumferential main groove 12 are further provided.
It is preferable that the connecting sipe 43 extends gradually toward the second side CD2 in the tire circumferential direction while moving away from the second ground contact end TE2, as in the example of FIG.
Although not shown, the connecting sipes 43, like the branch grooves 212 of the resonator 21, are connected to a tread-side sipe portion that opens in the tread surface 1 and extends inward in the tire radial direction, and from the tread-side sipe portion. It is preferable that the tire includes a tunnel portion that continuously extends inward in the tire radial direction and has a groove width larger than that of the tread side sipe portion. Thereby, the air in the second circumferential main groove 12 can pass through the tunnel portion of the connecting sipe 43 and enter into the second end land lug groove 42, making it possible to reduce noise. In this case, the tread-side sipe portion closes immediately under the load when the tire is assembled to the rim, filled with the above-mentioned predetermined internal pressure, and the maximum load is applied. It is preferable that the two parts are configured so that the two parts come into contact with each other.

In the tires of each example described in this specification, when the second end land portion lug groove 42 is provided in the second end land portion 40 as described above, the second end land portion 40 is provided with the second end land portion lug groove 42 in the tire circumferential direction. Between a pair of adjacent second end land lug grooves 42, a second end land sipe 41 having one end opening to the second grounding end TE2 and the other end opening to the second circumferential main groove 12, It is preferable that a plurality of them are provided.
It is preferable that the second end land portion sipe 41 extends gradually toward the second side CD2 in the tire circumferential direction while moving away from the second ground contact end TE2, as in the example of FIG.

In each tire example described in this specification, the resonator 21 may be arranged only on one side with respect to the tire equatorial plane CL. In this case, the resonator 21 may be disposed only on the outer side (OUT side) of the vehicle with respect to the tire equatorial plane CL, as in the example of FIG. It may be arranged only on the inside (IN side).
Alternatively, the resonator 21 may be placed on the tire equatorial plane CL.
Alternatively, the resonators 21 may be arranged on both sides with respect to the tire equatorial plane CL, as in the first modification shown in FIG. In this case, in the resonator 21 located on the second circumferential main groove 12 side with respect to the tire equatorial plane CL, the sub groove 211 terminates at both ends within the intermediate land portion 20, and the branch groove 212 terminates in the sub groove 211. and the second circumferential main groove 12, and has a smaller groove cross-sectional area than the sub-groove 211.

In each example tire described in this specification, it is preferable that the intermediate land portion 20 is located on the tire equatorial plane CL. Thereby, noise can be reduced more effectively.

In each tire example described in this specification, the intermediate land portion 20 may be provided with a narrow groove 23 on the tire equatorial plane CL, as in a second modification shown in FIG. In this case, drainage performance can be improved.
However, the rigidity of the intermediate land portion 20 can be improved when the narrow groove 23 is not provided as in the example of FIG.
When the narrow groove 23 is provided, the width of the narrow groove 23 is preferably 4% or less of the ground contact width TW.
Further, the groove depth of the narrow groove 23 is 75% of the groove depth D1 (FIG. 3) of each circumferential main groove 10 (in the illustrated example, the first circumferential main groove 11 and the second circumferential main groove 12). The following is preferable, and 50% or less is more preferable.

In each example tire described in this specification, the negative rate of the tread surface 1 is preferably 25 to 30%, and more preferably 25 to 29%.
Thereby, sufficient drainage performance can be ensured while suppressing a reduction in rigidity due to the provision of the resonator 21.
In this specification, "the negative ratio of the tread surface (1)" refers to the entire tread surface (1) when the tire is assembled to the rim, the internal pressure of the tire is 250 kPa, and a load of 4.17 kN is applied to the tire. Refers to the ratio of the area of the part of the tread surface (1) that does not come into contact with the road surface to the area of the tread surface (1). The "portions within the tread surface (1) that do not come into contact with the road surface" are comprised of various grooves and the like within the tread surface (1).

The tire according to the present invention can be used as any type of pneumatic tire, but is preferably used as a pneumatic tire for passenger cars.

1: Tread surface,
10: Circumferential main groove, 10a: Groove wall, 11: First circumferential main groove, 12: Second circumferential main groove,
20: intermediate land part, 20b: block part, 20c: corner part,
21: Resonator, 211: Minor groove, 211c: Groove width center line, 2111: First minor groove, 2112: Second minor groove, 212: Branch groove, 2121: Tread side sipe, 2122: Tunnel, 2123: Bottom side sipe part, 212a: opening extension part,
22: Intermediate land sipe,
23: Narrow groove,
30: First land area,
31: First end land lug groove,
40: Second edge land area,
41: 2nd endland sipe,
42: Second end land lug groove,
43: Connecting sipe,
60: belt, 61: belt layer,
70: carcass,
80: Tread rubber,
90: tread part,
TE1: 1st grounding end (grounding end), TE2: 2nd grounding end (grounding end),
CD1: first side in the tire circumferential direction, CD2: second side in the tire circumferential direction,
CL: Tire equatorial plane

Claims (19)

A tire comprising a first circumferential main groove and a second circumferential main groove on the tread surface,
A resonator is formed in an intermediate land section defined between the first circumferential main groove and the second circumferential main groove,
The resonator has a minor groove that terminates at both ends within the intermediate land portion,
The groove depth D1 of the first circumferential main groove and the second circumferential main groove is 50% or less of the groove width W2 of the first circumferential main groove and the second circumferential main groove, respectively,
A groove depth D3 of the minor groove of the resonator is 70% or more of a groove depth D1 of the first circumferential main groove,
A tire in which groove depth D1 of the first circumferential main groove and the second circumferential main groove are each 6.5 mm or less. The tire according to claim 1 , wherein a groove depth D3 of the sub-groove of the resonator is 5.5 mm or more. The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The tire according to claim 1 or 2 , wherein a groove depth D2 of the branch groove of the resonator is 70% or more of a groove depth D1 of the first circumferential main groove. The tire according to any one of claims 1 to 3 , wherein the maximum value of the groove width W3 of the sub-groove of the resonator is 60% or less of the groove depth D3 of the sub-groove. The groove width W2 of the first circumferential main groove and the second circumferential main groove is 5 to 15% of the ground contact width TW of the tire, respectively, according to any one of claims 1 to 4 . tire. The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The branch groove of the resonator has an acute inclination angle θ1 of 20 to 60 degrees with respect to the tire width direction at the end on the side opening to the first circumferential main groove. The tire described in any one of the items. The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
An acute inclination angle θ3 with respect to the tire width direction at the end of the sub-groove of the resonator that is far from the first circumferential main groove is equal to the inclination angle θ3 of the sub-groove of the resonator in the first circumferential direction. The tire according to any one of claims 1 to 6 , which is larger than an acute inclination angle θ1 with respect to the tire width direction at the end opening into the main groove. The minor groove of the resonator is
a first minor groove portion extending toward the first circumferential side of the tire while gradually moving away from the first circumferential major groove;
a second minor groove portion that is continuous from an end of the first minor groove portion closer to the first circumferential main groove and extends toward a second side in the tire circumferential direction;
has
An acute inclination angle θ6 with respect to the tire width direction at the end of the second sub-groove connected to the first sub-groove is equal to The tire according to claim 3, 6, or 7 , wherein the inclination angle θ4 on the acute side with respect to the tire width direction at the end is larger than the inclination angle θ4. 9. The first sub-groove of the sub-groove of the resonator has an inclination angle on an acute side with respect to the tire width direction that gradually increases as the distance from the first circumferential main groove increases. tire. A length L1 of the first sub-groove of the sub-groove of the resonator is 2.0 to 7.0 times the length L2 of the second sub-groove of the sub-groove of the resonator. 9. The tire according to 8 or 9 . Any one of claims 8 to 10 , wherein the branch groove of the resonator is connected to a connecting portion of the first sub-groove and the second sub-groove in the sub-groove of the resonator. Tires listed in. The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The pitch interval P1 of the branch grooves of the resonator in the tire circumferential direction is 2.5 to 5.0 times the groove depth D2 of the branch grooves, according to any one of claims 1 to 11 . tire. The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The branch groove of the resonator is
a tread side sipe portion that opens in the tread surface and extends inward in the tire radial direction;
a tunnel portion that continuously extends inward in the tire radial direction from the tread side sipe portion and has a groove width larger than that of the tread side sipe portion;
The tire according to any one of claims 1 to 12 , having: The tire according to any one of claims 1 to 13 , wherein the resonator is arranged only on one side with respect to the tire equatorial plane. The tire according to any one of claims 1 to 14 , wherein the width W1 of the intermediate land portion is 30 to 50% of the ground contact width TW of the tire. The tire according to any one of claims 1 to 15 , wherein the tread surface has a negative ratio of 25 to 30%. The tire according to any one of claims 1 to 16 , wherein the maximum value of the thickness T1 of the tread rubber is 8 mm or less. The intermediate land portion is located on the tire equatorial plane,
The tire according to any one of claims 1 to 17 , wherein the intermediate land portion is provided with a narrow groove on the tire equatorial plane. The resonator further includes a branch groove that extends to connect the minor groove and the first circumferential main groove and has a smaller groove cross-sectional area than the minor groove,
The groove wall of the first circumferential main groove is curved convexly toward the inner side in the tire radial direction and the outer side in the groove width direction,
The tire according to any one of claims 1 to 18 , wherein the branch groove of the resonator extends to the groove wall of the first circumferential main groove.

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