JP7790108B2 - tire - Google Patents

Description

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

Tires with lateral grooves extending under the tread have been disclosed (see, for example, Patent Document 1).

Special Publication No. 2012-501914

The tire disclosed in Patent Document 1 does not provide sufficient wet performance in the early stages of wear when the submerged lateral grooves are hidden. On the other hand, as the tread wear progresses, the submerged lateral grooves become visible, causing greater deformation of the tread and reducing fuel economy.

This disclosure was devised in light of the above-mentioned circumstances, and its primary objective is to provide a tire that provides balanced fuel economy and wet performance regardless of the state of wear.

The present disclosure provides a tire having a tread portion,
A plurality of axially extending lateral grooves are formed in the tread portion,
The lateral groove includes a narrow groove portion and a widened portion,
the narrow groove portion has a groove width that closes when the tire is under normal load,
the widened portion communicates with an inner end of the narrow groove portion in the tire radial direction,
the widened portion has a groove width that is larger than the groove width of the narrow groove portion and does not close under the normal load condition,
The lateral grooves are
a first lateral groove, the narrow groove portion and the widened portion communicating with each other at a first distance from the tread surface of the tread portion;
a second lateral groove, the communication position of which is located at a second distance from the tread surface that is greater than the first distance;
It's a tire.

In the tire disclosed herein, in the early stages of tread wear, the narrow groove portions are closed under the normal load, suppressing deformation of the tread and reducing rolling resistance. Meanwhile, as tread wear progresses, the widened portions that are not closed under the normal load appear, improving drainage performance. Furthermore, the lateral grooves include the first lateral groove and the second lateral groove, which have different connection positions between the narrow groove portions and the widened portions. As wear progresses, it is possible to stagger the timing at which the widened portions appear in the first lateral groove and the second lateral groove. Therefore, balanced fuel economy and wet performance can be achieved regardless of the state of wear.

1 is a perspective view of a tread portion showing one embodiment of a tire of the present disclosure. FIG. 2 is a cross-sectional view showing a tread portion under normal load conditions. FIG. 2 is a perspective view of a tread portion in which a plurality of lateral grooves having different distances D are formed. FIG. 4 is a cross-sectional view showing the tread portion of FIG. 3 under a normal load. FIG. 4 is a development view of a modified example of the transverse groove of FIG. 3 . FIG. 4 is a perspective view of a modification of the tread portion of FIG. 3 . FIG. 7 is a development view of the tread portion of FIG. 6. FIG. 7 is a perspective view of a modification of the tread portion of FIG. 6 . FIG. 9 is a development view of a tread portion including the configuration of FIG. 8.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.
FIG. 1 is a perspective view of a tire tread portion 2 of the present embodiment, with a portion cut away.

The tread portion 2 has multiple lateral grooves 3 extending in the tire axial direction (a direction intersecting the tire equator). The lateral grooves 3 may be parallel to the tire axial direction or may be inclined relative to the tire axial direction.

The lateral groove 3 includes a narrow groove portion 4 and a widened portion 5.

The narrow grooves 4 are open at the tread surface 21 of the tread portion 2. The narrow grooves 4 have a groove width that closes when the tire is under normal load.

"Normal load condition" refers to a state in which a normal load is applied to a tire in normal condition, with the tire in contact with a flat surface at a camber angle of 0°.

"Normal condition" means, in the case of a pneumatic tire, that the tire is mounted on a normal rim (not shown), inflated to the normal internal pressure, and unloaded. In the case of an airless tire, it means that the tire is mounted on a normal rim. Unless otherwise specified below, the dimensions of each part of the tire are values measured in this normal condition.

A "genuine rim" is a rim specified for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "design rim," and in the case of ETRTO, it is called a "measuring rim."

"Normal internal pressure" refers to the air pressure specified for each tire in the standard system, including the standard on which the tire is based. For JATMA, this is the "maximum air pressure," for TRA, this is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, this is the "INFLATION PRESSURE." If the tire is for a passenger car, the normal internal pressure is, for example, 180 kPa.

"Normal load" refers to the load specified for each tire in the standard system, including the standard on which the tire is based. For JATMA, this is "maximum load capacity." For TRA, this is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." For ETRTO, this is "LOAD CAPACITY." If the tire is for a passenger car, the normal load is, for example, a load equivalent to 88% of the vehicle's load.

The widened portion 5 is connected to the radially inner end of the narrow groove portion 4. The widened portion 5 has a groove width that is larger than the groove width of the narrow groove portion 4 and does not close under normal load conditions. The groove width of the narrow groove portion 4 is, for example, less than 1.5 mm, and the groove width of the widened portion 5 is, for example, 1.5 mm or more.

Figure 2 shows a portion of the tread portion 2 under normal load. When a normal load is applied, the narrow grooves 4 are closed, increasing the circumferential rigidity of the tread portion 2. This suppresses deformation of the tread portion 2 and reduces rolling resistance.

In the tire of this embodiment, in the early stages of wear of the tread portion 2, the narrow groove portions 4 are closed under normal load, thereby suppressing deformation of the tread portion 2 and reducing rolling resistance. Meanwhile, as wear of the tread portion 2 progresses, widened portions 5 appear that do not close even under normal load, improving drainage performance.

In the tire of this embodiment, the radial distance D from the tread surface 21 of the tread portion 2 to the connection position 45 between the narrow groove portion 4 and the widened portion 5 is not constant along the length of the lateral groove 3. With such lateral grooves 3, the narrow groove portion 4 and the widened portion 5 coexist as the tread portion 2 wears. This allows for balanced fuel economy and wet performance to be achieved regardless of the degree of wear.

The distance D being "non-constant in the longitudinal direction" means that the distance D is not a constant value in the longitudinal direction of the lateral groove 3 (in other words, in the axial direction of the tire). Therefore, the distance D may vary continuously in the longitudinal direction of the lateral groove 3, or may vary in stages. Furthermore, as shown in Figure 1, the distance D is not limited to varying in a single lateral groove 3; multiple lateral grooves 3 with different distances D may be formed in the tread portion 2.

Figure 3 shows a portion of a tread portion 2 in which multiple lateral grooves 3 with different distances D are formed. That is, the lateral grooves 3 include first lateral grooves 31 and second lateral grooves 32.

The first lateral groove 31 is a lateral groove 3 whose communication position 45 is located a first distance D1 from the tread surface 21. The second lateral groove 32 is a lateral groove 3 whose communication position 45 is located a second distance D2 from the tread surface 21. The first distance D1 and the second distance D2 themselves may be constant or may not be constant.

In Figure 3, the second distance D2 is greater than the first distance D1. Therefore, as wear progresses, the widened portions 5 of the first lateral grooves 31 appear first on the tread surface 21 of the tread portion 2, improving wet performance. At this time, the narrow groove portions 4 of the second lateral grooves 32 open to the tread surface 21. The narrow groove portions 4 of the second lateral grooves 32 close under normal load, suppressing deformation of the tread portion 2. This provides balanced fuel economy and wet performance regardless of the degree of wear.

Figure 4 shows a portion of the tread portion 2 of Figure 3 under normal load conditions. Under normal load, the narrow groove portions 4 of the first lateral grooves 31 and second lateral grooves 32 are closed, increasing the circumferential rigidity of the tread portion 2. This suppresses deformation of the tread portion 2 and reduces rolling resistance.

In the tire of this embodiment, in the early stages of wear of the tread portion 2, the narrow groove portions 4 of the first lateral grooves 31 and second lateral grooves 32 are closed under normal load, thereby suppressing deformation of the tread portion 2 and reducing rolling resistance. Meanwhile, as wear of the tread portion 2 progresses, widened portions 5 appear that do not close even under normal load, improving drainage performance.

In Figures 3 and 4, the lateral grooves 3 include first lateral grooves 31 and second lateral grooves 32, which have different connection positions 45 between the narrow groove portions 4 and the widened portions 5. This makes it possible to shift the timing at which the widened portions 5 appear in the first lateral grooves 31 and second lateral grooves 32 as wear progresses. Therefore, balanced fuel economy and wet performance can be achieved regardless of the progress of wear.

It is desirable that the first distance D1 be 80% or less of the second distance D2. By making the first distance D1 80% or less of the second distance D2, it is possible to stagger the timing at which the widened portions 5 appear in the first lateral grooves 31 and the second lateral grooves 32, resulting in better balanced fuel economy and wet performance.

It is desirable that the first lateral grooves 31 and the second lateral grooves 32 be arranged alternately in the circumferential direction of the tire. This allows the first lateral grooves 31 and the second lateral grooves 32 to alternately come into contact with the ground in the rolling tread portion 2, resulting in even better balanced fuel economy and wet performance.

Figure 5 shows a modified example of the lateral groove 3 in Figure 1. As shown in Figure 5, the lateral groove 3 may extend in a zigzag pattern. The lateral grooves 3 in Figure 3, i.e., the first lateral grooves 31 and second lateral grooves 32, may also extend in a zigzag pattern. In this type of lateral groove 3, the narrow groove portions 4 are closed under normal load, thereby increasing the circumferential and axial rigidity of the tread portion 2 and further improving fuel economy. Note that in the lateral grooves 3, the narrow groove portions 4 may extend in a zigzag pattern and the widened portions 5 may extend linearly.

Figure 6 shows a modified example of the tread portion 2 in Figure 1. As shown in Figure 6, it is desirable that the tread portion 2 has circumferential grooves 6 formed therein that extend in the circumferential direction of the tire.

The circumferential groove 6 includes a narrow groove portion 7 and a widened portion 8.

The narrow groove portion 7 is open at the tread surface 21 of the tread portion 2. The narrow groove portion 7 has a groove width that closes when the tire is under normal load.

The widened portion 8 is connected to the radially inner end of the narrow groove portion 7. The widened portion 8 has a groove width that is larger than the groove width of the narrow groove portion 7 and does not close under normal load conditions.

The formation of circumferential grooves 6 in the tread portion 2 improves the wet performance of the tire. Furthermore, in the early stages of wear of the tread portion 2, the narrow groove portions 7 close under normal load, suppressing deformation of the tread portion 2 and reducing rolling resistance. Meanwhile, as wear of the tread portion 2 progresses, widened portions 8 appear that do not close even under normal load, improving drainage performance.

It is desirable that the lateral grooves 3 communicate with the circumferential grooves 6. This allows water to flow between the lateral grooves 3 and the circumferential grooves 6, improving the drainage performance of the tread portion 2.

The lateral grooves 3 may also be connected to circumferential grooves (not shown) that do not include narrow groove portions 7. In this configuration, regardless of whether the narrow groove portions 4 are blocked, water that flows into the circumferential grooves flows into the widened portions 5 of the lateral grooves 3, thereby improving the drainage performance of the tread portion 2.

The circumferential grooves 6 may extend in a zigzag pattern. In circumferential grooves 6 of this type, the narrow groove portions 7 close under normal load, thereby increasing the axial and circumferential rigidity of the tread portion 2 and further improving fuel economy.

Figure 7 shows the tread surface 21 of the tread portion 2 in Figure 6. In Figures 6 and 7, the first lateral grooves 31 and the second lateral grooves 32 are arranged on one axial side of the circumferential grooves 6.

The narrow groove portions 4 of the first lateral grooves 31 preferably communicate with the narrow groove portions 7 of the circumferential grooves 6 at an angle θ1 of 60° to 120°. This improves the traction performance of the tread portion 2. Similarly, the narrow groove portions 4 of the second lateral grooves 32 preferably communicate with the narrow groove portions 7 of the circumferential grooves 6 at an angle θ2 of 60° to 120°.

Figure 8 is another diagram showing a modified example of the tread portion 2 of Figure 6. As shown in Figure 8, the depth D13 of the widened portion 8 of the circumferential groove 6 is preferably greater than the width W of the widened portion 8 of the circumferential groove 6. This prevents a sudden change in wet performance as wear progresses. It also makes it easier to ensure wet performance even in the final stages of wear.

The first distance D1 and the second distance D2 are preferably 100 to 150% of the third distance D3 from the tread surface to the connecting position 78 between the narrow groove portion 7 and the widened portion 8 of the circumferential groove 6.

By making the first distance D1 and the second distance D2 100% or more of the third distance D3, the widened portions 5 of the first lateral grooves 31 and the second lateral grooves 32 communicate with the widened portions 8 of the circumferential grooves 6, improving wet performance. Also, rolling resistance is reduced in the early stages of wear. On the other hand, by making the first distance D1 and the second distance D2 150% or less of the third distance D3, the circumferential rigidity of the tread portion 2 is maintained, reducing rolling resistance, while good wet performance can be easily achieved in the final stages of wear due to the widened portions 8 of the circumferential grooves 6.

The depth D11 of the widened portion 5 of the first lateral groove 31 is preferably smaller than the depth D13 of the widened portion 8 of the circumferential groove 6. The depth D12 of the widened portion 5 of the second lateral groove 32 is preferably smaller than the depth D13 of the widened portion 8 of the circumferential groove 6. This maintains the circumferential rigidity of the tread portion 2 and reduces rolling resistance, while the widened portion 8 of the circumferential groove 6 easily provides good wet performance in the final stages of wear.

The depths D11 and D12 of the widened portions 5 of the lateral grooves 3 are preferably 30 to 50% of the depth D13 of the widened portions 8 of the circumferential grooves 6.

By making depths D11 and D12 30% or more of depth D13, wet traction performance at the end of wear is improved. By making depths D11 and D12 50% or less of depth D13, it is possible to suppress a decrease in the circumferential rigidity of the tread portion 2 and reduce rolling resistance.

Figure 9 shows the tread portion 2A, which includes the configuration of the tread portion 2 described above.

The tread portion 2A is formed with a pair of circumferential grooves 106 extending in the circumferential direction of the tire and multiple lateral grooves 103 extending in the axial direction of the tire.

Each circumferential groove 106 is arranged on both sides of the tire equator C. The circumferential grooves 106 extend in a zigzag pattern.

Each lateral groove 103 is arranged axially outward of the circumferential groove 106. The lateral grooves 103 are in communication with the circumferential grooves 106.

The circumferential groove 106 includes a narrow groove portion 7 and a widened portion 8 shown in FIG. 6. The lateral groove 103 includes a first lateral groove 31 and a second lateral groove 32 shown in FIG. 6. The first lateral groove 31 and the second lateral groove 32 include a narrow groove portion 4 and a widened portion 5 shown in FIG. 6.

The tread portion 2A having the above configuration achieves the same effects as the tread portion 2.

A pair of wide circumferential grooves 107 are formed axially outboard of the lateral grooves 103, with a groove width that does not close under normal load conditions. The wide circumferential grooves 107 are formed in a zigzag pattern. The lateral grooves 103 are connected to the wide circumferential grooves 107. This makes it easy to achieve good wet performance near the shoulders from the early to late stages of wear.

Between adjacent lateral grooves 3 in the tire circumferential direction, multiple wide lateral grooves 104 are formed, each with a groove width that does not close under normal load conditions. The wide lateral grooves 104 are connected to the circumferential grooves 106 and the wide circumferential grooves 107. This makes it easy to achieve good wet traction performance from the early to late stages of wear.

The tires of the present disclosure have been described in detail above, but the present disclosure is not limited to the specific embodiments described above and may be modified in various ways.

Pneumatic tires with a size of 315/70R22.5 and the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 1, and their fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Note that wet performance at end-of-wear stages was tested using tires in which the rubber in the tread had been removed by buffing until the remaining circumferential groove depth was 3 mm (the same applies hereinafter). Specifications of each test tire that are not listed in Table 1 are common to all tires. For example, the first distance D1 is 8.5 mm, the second distance D2 is 11.0 mm (the same applies to Tables 2 to 8). The third distance D3 is 8.0 mm (the same applies to Tables 2 to 5 and 7 to 8). The test method was as follows:

<Fuel efficiency>
Each test tire was mounted on a 22.5x9.00 rim at an internal pressure of 900 kPa, and the rolling resistance was measured using a rolling resistance tester at a load of 31.25 kN and a speed of 80 km/h. The results are expressed as an index, with Comparative Example 1 being set at 100, and a larger index indicates lower rolling resistance and better fuel economy.

<Wet performance>
The wet performance of each test tire was tested in accordance with the UN-ECE R117 certification test. That is, each test tire was run on a wet road surface with 0.5 mm of water depth at a speed of 65±2 km/h under a load of 75% of the load index, and the braking distance was measured. The results were expressed as an index, with Comparative Example 1 being set at 100, and a larger index indicates a shorter braking distance and better wet performance.

As is clear from Table 1, the tires of the examples were found to have significantly improved wet performance at the end of wear compared to the comparative example, while maintaining the same fuel economy and wet performance as new tires.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 2, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications of each test tire that are not listed in Table 2 are common to all tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 2 being set at 100, and a larger index value indicates lower rolling resistance and better fuel economy.

<Wet performance>
The braking distance of each test tire was measured in the same manner as above. The results are expressed as an index, with Example 2 being set at 100, and a larger index indicates a shorter braking distance and better wet performance.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 3, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications of each test tire that are not listed in Table 3 are common to all tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 4 being 100, and a larger index indicates lower rolling resistance and better fuel economy.

<Wet performance>
The braking distance of each test tire was measured in the same manner as above. The results are expressed as an index, with Example 4 being 100, and a larger index indicates a shorter braking distance and better wet performance.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 4, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications of each test tire that are not listed in Table 4 are common to all test tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 9 being 100, and a larger index indicates lower rolling resistance and better fuel economy.

<Wet performance>
The braking distance of each test tire was measured in the same manner as above. The results are expressed as an index, with Example 9 being set at 100, and a larger index indicates a shorter braking distance and better wet performance.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 5, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications for each test tire that are not listed in Table 5 are common to all tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 14 being set at 100, and a larger index value indicates lower rolling resistance and better fuel economy.

<Wet performance>
The braking distance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 14 being set at 100, with a larger index indicating a shorter braking distance and better wet performance.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 6, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications of each test tire that are not listed in Table 6 are common to all test tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 19 being set at 100, and a larger index value indicates lower rolling resistance and better fuel economy performance.

<Fuel efficiency>
The braking distance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 19 being set at 100, with a larger index indicating a shorter braking distance and better wet performance.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 7, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications of each test tire that are not listed in Table 7 are common to all test tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 24 being set at 100, and a larger index value indicates lower rolling resistance and better fuel economy.

<Fuel efficiency>
The braking distance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 24 being 100, and a larger index indicates a shorter braking distance and better wet performance.

Pneumatic tires of the above sizes and having the basic pattern shown in Figure 9 were prototyped based on the specifications in Table 8, and similarly to the above, fuel economy performance and wet performance at new and end-of-wear stages were evaluated. Specifications of each test tire that are not listed in Table 8 are common to all test tires. The test method is as follows:

<Fuel efficiency>
The rolling resistance of each test tire was measured in the same manner as above. The results were expressed as an index, with Example 29 being set at 100, and a larger index value indicates lower rolling resistance and better fuel economy.

<Wet performance>
The braking distance of each test tire was measured in the same manner as above. The results are expressed as an index, with Example 29 being set at 100, and a larger index indicates a shorter braking distance and better wet performance.

[Note]
The present disclosure includes the following aspects.

[Disclosure 1]
A tire having a tread portion,
A plurality of axially extending lateral grooves are formed in the tread portion,
The lateral groove includes a narrow groove portion and a widened portion,
the narrow groove portion has a groove width that closes when the tire is under normal load,
the widened portion communicates with an inner end of the narrow groove portion in the tire radial direction,
the widened portion has a groove width that is larger than the groove width of the narrow groove portion and does not close under the normal load condition,
The lateral grooves are
a first lateral groove, the narrow groove portion and the widened portion communicating with each other at a first distance from the tread surface of the tread portion;
a second lateral groove, the communication position of which is located at a second distance from the tread surface that is greater than the first distance;
tire.
[Disclosure 2]
The tire of Disclosure 1, wherein the first distance is less than or equal to 80% of the second distance.
[Disclosure 3]
The tire according to Disclosure 1 or 2, wherein the first lateral grooves and the second lateral grooves are arranged alternately in the tire circumferential direction.
[Disclosure 4]
The tire according to any one of Disclosures 1 to 3, wherein the narrow groove portions of the lateral grooves extend in a zigzag shape.
[Disclosure 5]
The tread portion has a circumferential groove extending in the tire circumferential direction,
The circumferential groove includes a narrow groove portion and a widened portion,
the narrow groove portion has a groove width that closes when the tire is under normal load,
the widened portion communicates with an inner end of the narrow groove portion in the tire radial direction,
The tire according to any one of Disclosures 1 to 4, wherein the widened portion has a groove width that is larger than the groove width of the narrow groove portion and does not close under the normal load condition.
[Disclosure 6]
The tire according to Disclosure 5, wherein the lateral grooves are in communication with the circumferential grooves.
[Disclosure 7]
The tire according to Disclosure 6, wherein the narrow groove portions of the lateral grooves communicate with the narrow groove portions of the circumferential grooves at an angle of 60° to 120°.
[Disclosure 8]
The tire according to any one of Disclosures 5 to 7, wherein a depth of the widened portion of the circumferential groove is greater than a width of the widened portion of the circumferential groove.
[Disclosure 9]
The tire according to any one of Disclosures 5 to 8, wherein the first distance and the second distance are 100 to 150% of a third distance from the tread surface to a communication position between the narrow groove portion and the widened portion of the circumferential groove.
[Disclosure 10]
The tire according to any one of the present disclosures 5 to 9, wherein a depth of the widened portion of the lateral groove is smaller than a depth of the widened portion of the circumferential groove.
[Disclosure 11]
The tire described in the present disclosure 10, wherein the depth of the widened portion of the lateral groove is 30 to 50% of the depth of the widened portion of the circumferential groove.
[Disclosure 12]
The tire according to any one of claims 6 to 11, wherein the circumferential groove extends in a zigzag pattern.
[Disclosure 13]
The tire according to any one of disclosures 6 to 12, wherein the lateral grooves are arranged axially outward of the circumferential grooves.
[Disclosure 14]
A wide circumferential groove having a groove width that does not close under the normal load condition is formed on the tire axially outer side of the lateral groove,
The tire of disclosure 13, wherein the lateral grooves are in communication with the wide circumferential groove.
[Disclosure 15]
The tire according to present disclosure 14, wherein wide lateral grooves having a groove width that does not close under the normal load condition are formed between the lateral grooves adjacent in the tire circumferential direction.
[Disclosure 16]
The tire of present disclosure 15, wherein the wide lateral groove is in communication with the circumferential groove and the wide circumferential groove.

2 Tread portion 3 Lateral groove 4 Narrow groove portion 5 Widened portion 6 Circumferential groove 7 Narrow groove portion 8 Widened portion 21 Ground contact surface 23 Tread portion 31 First lateral groove 32 Second lateral groove 45 Communication position 78 Communication position D Distance D1 First distance D2 Second distance D3 Third distance

Claims (14)

A tire having a tread portion,
A plurality of axially extending lateral grooves are formed in the tread portion,
The lateral groove includes a lateral narrow groove portion and a lateral widened portion,
the lateral narrow groove portion has a groove width that closes when the tire is under normal load,
the lateral widened portion communicates with an inner end of the lateral narrow groove portion in the tire radial direction,
the lateral widened portion has a groove width that is larger than the groove width of the lateral narrow groove portion and does not close under the normal load condition,
The lateral grooves are
a first lateral groove, the lateral narrow groove portion and the lateral widened portion communicating with each other at a first distance from the tread surface of the tread portion;
a second lateral groove, the communication position of which is located at a second distance from the tread surface that is greater than the first distance ;
The tread portion has a circumferential groove extending in the tire circumferential direction,
The circumferential groove includes a circumferential narrow groove portion and a circumferential widened portion,
the circumferential narrow groove portion has a groove width that closes when the tire is in the normal load state,
the circumferential widened portion is in communication with an inner end of the circumferential narrow groove portion in the tire radial direction,
the circumferential widened portion has a groove width that is larger than the groove width of the circumferential narrow groove portion and does not close under the normal load condition,
The length of the circumferential widening portion in the tire radial direction is greater than the width of the circumferential widening portion.
tire. A tire having a tread portion,
A plurality of axially extending lateral grooves are formed in the tread portion,
The lateral groove includes a lateral narrow groove portion and a lateral widened portion,
the lateral narrow groove portion has a groove width that closes when the tire is under normal load,
the lateral widened portion communicates with an inner end of the lateral narrow groove portion in the tire radial direction,
the lateral widened portion has a groove width that is larger than the groove width of the lateral narrow groove portion and does not close under the normal load condition,
The lateral grooves are
a first lateral groove, the lateral narrow groove portion and the lateral widened portion communicating with each other at a first distance from the tread surface of the tread portion;
a second lateral groove, the communication position of which is located at a second distance from the tread surface that is greater than the first distance;
The tread portion has a circumferential groove extending in the tire circumferential direction,
The circumferential groove includes a circumferential narrow groove portion and a circumferential widened portion,
the circumferential narrow groove portion has a groove width that closes when the tire is in the normal load state,
the circumferential widened portion is in communication with an inner end of the circumferential narrow groove portion in the tire radial direction,
the circumferential widened portion has a groove width that is larger than the groove width of the circumferential narrow groove portion and does not close under the normal load condition,
The length of the lateral widening portion in the tire radial direction is smaller than the length of the circumferential widening portion in the tire radial direction.
tire. The tire of claim 1 or 2, wherein the first distance is 80% or less of the second distance . The tire according to claim 1 , wherein the first lateral grooves and the second lateral grooves are arranged alternately in the tire circumferential direction. The tire according to claim 1 , wherein the lateral narrow groove portion extends in a zigzag pattern in the tire axial direction . The tire according to claim 1 , wherein the lateral grooves communicate with the circumferential grooves . 7. The tire according to claim 1, wherein the lateral narrow groove portion communicates with the circumferential narrow groove portion at an angle of 60° to 120° . 8. The tire according to claim 1, wherein the first distance and the second distance are 100 to 150% of a third distance from the tread surface to a connecting position between the circumferential narrow groove portion and the circumferential widened portion . The tire according to any one of claims 1 to 8, wherein the length of the laterally widened portion in the tire radial direction is 30 to 50% of the length of the circumferentially widened portion in the tire radial direction . The tire according to any one of claims 6 to 9, wherein the circumferential groove extends in a zigzag pattern in the tire circumferential direction . The tire according to claim 6 , wherein the lateral grooves are arranged axially outward of the circumferential grooves . A wide circumferential groove having a groove width that does not close under the normal load condition is formed on the tire axially outer side of the lateral groove,
The tire of claim 11 , wherein the lateral grooves communicate with the wide circumferential grooves . The tire according to claim 12 , wherein wide lateral grooves having a groove width that does not close under the normal load condition are formed between the lateral grooves adjacent to each other in the tire circumferential direction . The tire according to claim 13 , wherein the wide lateral groove communicates with the circumferential groove and the wide circumferential groove .