JP7841314B2 - tire - Google Patents

Description

This disclosure relates to tires.

Patent Document 1 below proposes a tire for SUVs intended for off-road driving. This tire aims to improve grip performance on rocky and snow/mud surfaces while maintaining the durability of the crown blocks by specifically designing the crown blocks.

Japanese Patent Publication No. 2021-062655

In recent years, tires have been required to have even greater performance on snow. At the same time, tires also need to consider handling stability on dry surfaces.

This disclosure was devised in light of the above-described circumstances, and its primary purpose is to provide a tire that can exhibit excellent snow performance while maintaining handling stability on dry surfaces.

This disclosure relates to a tire having a tread portion, the tread portion comprising at least two circumferential grooves extending continuously in the circumferential direction of the tire, a plurality of crown lateral grooves connecting the two circumferential grooves, and a crown land portion divided between the two circumferential grooves, wherein the crown land portion alternately comprises a first region and a second region divided by the plurality of crown lateral grooves in the circumferential direction of the tire, the first region comprising a first crown block having a first tread surface, the second region comprising at least one second crown block having a second tread surface, and the second crown block is connected to the first crown block via the crown lateral grooves. The tires are adjacent to each other, and in a plan view of the tread, the first crown block is arranged such that the longest possible straight line that can be drawn on the first tread surface is less than 45° with respect to the tire axis, the first tread surface has a maximum length L2 in the direction perpendicular to the longest straight line that is 50% or less of the length L1 of the longest straight line, and the second tread surface of the second crown block is a polygonal shape on which a longest diagonal and a shortest diagonal can be drawn that divide the second tread surface into two parts having 45% or more of its area, and the length of the longest diagonal is 160% or less of the length of the shortest diagonal.

By adopting the above configuration, the tire disclosed herein can maintain handling stability on dry surfaces while exhibiting excellent performance on snow.

This is an exploded view of the tread portion of a tire according to one embodiment of the present disclosure. Figure 1 is an enlarged view of the Crown Land area. Figure 2 is an enlarged view of the first crown block. Figure 2 is an enlarged view of the second crown block. This is an enlarged view of the circumferential grooves in Figure 1. This is a magnified view of the connection part shown in Figure 5. Figure 1 is an enlarged view of the shoulder area.

The following describes one embodiment of this disclosure based on the drawings. Figure 1 is an exploded view of the tread portion 2 of the tire 1 of this embodiment. As shown in Figure 1, the tire 1 of this embodiment is suitably used, for example, as a pneumatic tire for an SUV that is also intended for off-road driving. However, the tire 1 of this disclosure is not limited to this embodiment.

The tread portion 2 of the tire 1 in this embodiment includes two tread edges Te, at least two circumferential grooves 3, and a plurality of crown lateral grooves 10. The tread portion 2 of this embodiment has a pattern that is point-symmetric with respect to a point on the tire equator C. Therefore, the pattern elements between one tread edge Te and the tire equator C, and the pattern elements between the other tread edge Te and the tire equator C, have substantially the same configuration, except that their orientations in the circumferential direction of the tire are opposite. However, the tire 1 of this disclosure is not limited to this embodiment.

The tread edge Te is the outermost contact point in the tire's axial direction when tire 1, in its normal state, is loaded with 70% of its normal load, has a camber angle of 0°, and is in contact with a flat surface.

"Normal condition" refers to the state in the case of pneumatic tires for which various standards are defined, where the tire is mounted on a normal rim, filled to the normal internal pressure, and under no load. For tires for which various standards are not defined, or for non-pneumatic tires, the normal condition refers to the standard operating condition according to the tire's intended use, and is under no load. Unless otherwise specified in this specification, the dimensions of each part of the tire are values measured under the normal condition. Furthermore, unless otherwise specified in this specification, known methods may be appropriately applied to the measurement methods of the aforementioned dimensions and material composition.

A "standard rim" is the rim specified for each tire within the tire's standardization system, including the standard on which the tire is based. For example, it would be a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO.

"Regular internal pressure" refers to the air pressure specified for each tire within the tire standard system, including the standard on which the tire is based. For JATMA, this is the "maximum air pressure"; for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it is the "INFLATION PRESSURE."

"Regular load" refers to the load specified for each tire within the standard system, including the standard on which the tire is based, for pneumatic tires with various defined standards. For example, it's the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. For tires without defined standards, "regular load" refers to the maximum load applicable to the tire's use, in accordance with the aforementioned standards.

The circumferential grooves 3 extend continuously in the circumferential direction of the tire. In this embodiment, the circumferential grooves 3 extend in a zigzag pattern. In this embodiment, two circumferential grooves 3 are provided so as to sandwich the tire equator C. The crown lateral groove 10 in this embodiment connects these two circumferential grooves 3. Furthermore, the tread portion 2 includes a crown land portion 4 divided between the two circumferential grooves 3. The tread portion 2 in this embodiment also includes a shoulder land portion 5 divided on the tread end Te side of the circumferential grooves 3.

The circumferential groove 3 includes, for example, a portion inclined at an angle of 10 to 40° with respect to the tire's circumferential direction. The axial distance L3 from the tire equator C to the inner end of the circumferential groove 3 (the end closest to the tire equator C) is, for example, 5% to 15% of the tread width TW. The axial distance L4 from the tire equator C to the outer end of the circumferential groove 3 (the end closest to the tread edge Te) is, for example, 25% to 35% of the tread width TW. The tread width TW is the maximum axial distance from one tread edge Te to the other tread edge Te in the normal state.

Figure 2 shows an enlarged view of the crown area 4. As shown in Figure 2, the crown area 4 alternately includes a first region 4A and a second region 4B in the circumferential direction of the tire, separated by a plurality of crown lateral grooves 10. The first region 4A includes a first crown block 26 having a first tread surface 26a. In this embodiment, the first region 4A is composed of one first crown block 26. The second region 4B includes at least one second crown block 27 having a second tread surface 27a. Preferably, one second region 4B contains two or more second crown blocks 27, and in this embodiment, the second region 4B is composed of two second crown blocks 27. The second crown blocks 27 are separated by circumferential grooves 3, crown lateral grooves 10, and crown longitudinal grooves 13, and are adjacent to the first crown block 26 via the crown lateral grooves 10.

Figure 3 shows an enlarged plan view of the first crown block 26. As shown in Figure 3, in a plan view of the tread, the first crown block 26 is positioned such that the longest possible straight line 30 that can be drawn on the first tread surface 26a has an angle θ4 with respect to the tire axis that is less than 45°. Furthermore, the maximum length L2 of the first tread surface 26a of the first crown block 26, in the direction perpendicular to the longest straight line 30, is 50% or less of the length L1 of the longest straight line 30.

Figure 4 shows an enlarged plan view of the second crown block 27. As shown in Figure 4, the second tread surface 27a of the second crown block 27 is a polygonal shape from which multiple equal-diagonal lines 35 can be drawn, dividing the second tread surface 27a into two parts having an area of 45% or more. These equal-diagonal lines include a maximum diagonal 36 and a minimum diagonal 37. The maximum diagonal 36 refers to the one with the longest length among the multiple equal-diagonal lines 35. The minimum diagonal 37 refers to the one with the shortest length among the multiple equal-diagonal lines 35. In this specification, a polygonal shape includes both convex polygonal shapes where all interior angles are less than 180°, and concave polygonal shapes that include interior angles greater than 180°. In this embodiment, the first tread surface 26a and the second tread surface 27a are concave polygonal shapes.

In this disclosure, the length L7 of the maximum diagonal 36 is set to be 160% or less of the length L8 of the minimum diagonal 37. By adopting the above configuration, the tire 1 of this disclosure can exhibit excellent snow performance while maintaining handling stability on dry surfaces (hereinafter sometimes simply referred to as "handling stability"). The mechanism is as follows:

In this disclosure, the first crown block 26, having the above-described configuration, is easily deformable in the circumferential direction of the tire. On the other hand, the second crown block 27, having the above-described configuration, has greater rigidity in the circumferential direction of the tire compared to the first crown block 26. Therefore, when driving on snow, the first crown block 26 tilts in the circumferential direction of the tire, causing the snow to be strongly compressed between the first crown block 26 and the second crown block 27, resulting in a large snow column shear force. Furthermore, because the second crown block 27 has greater rigidity in the circumferential direction of the tire, handling stability on dry surfaces can be maintained. In this disclosure, this mechanism makes it possible to exhibit excellent snow performance while maintaining handling stability on dry surfaces.

The following describes the configuration of this embodiment in more detail. Note that each configuration described below represents a specific aspect of this embodiment. Therefore, it goes without saying that this disclosure can achieve the above-described effects even without the configurations described below. Furthermore, even if any one of the configurations described below is applied individually to a tire of this disclosure having the above-described features, an improvement in performance corresponding to each configuration can be expected. Moreover, if several of the configurations described below are applied in combination, a combined improvement in performance corresponding to each configuration can be expected.

As shown in Figure 2, the first crown block 26 is provided, for example, on the tire equator C, and the second crown block 27 is provided one on each side of the tire equator C in the tire axial direction. However, this disclosure is not limited to this embodiment.

As shown in Figure 3, from the viewpoint of ensuring snow column shear force in the tire axial direction, the angle θ5 of the maximum straight section 30 with respect to the tire axial direction is, for example, 30° or more. Furthermore, the length L1 of the maximum straight section 30 is, for example, 35% to 55% of the tread width TW (shown in Figure 1). Such a first crown block 26 helps to improve both handling stability and snow performance in a balanced way.

In the first crown block 26, the length L2 is, for example, 25% to 50% of the length L1 of the maximum straight section 30, preferably 30% to 40%. This suppresses uneven wear of the first crown block 26 while achieving the above-mentioned effects.

The first crown block 26 includes a main portion 40 and sub-portions 41 extending from both sides of the main portion 40 in the tire axial direction. The main portion 40 includes two edges 40a extending parallel to each other. The sub-portions 41 include two edges 41a extending toward each other toward the tire axial end of the first crown block 26. The angle θ6 between the two edges 41a of the sub-portions 41 is, for example, 30 to 60°, preferably 40 to 50°. Such a first crown block 26 allows the sub-portions 41 to deform appropriately during snow driving, enabling the discharge of snow from the circumferential grooves 3 and crown lateral grooves 10, thus maintaining excellent snow performance.

As shown in Figure 4, in the second crown block 27, it is desirable that the length L8 of the minimum diagonal 37 is 60% or more of the length L7 of the maximum diagonal 36. This reduces the anisotropy of the rigidity of the second crown block 27, resulting in a well-balanced improvement in traction and cornering performance on dry surfaces.

In this embodiment, the maximum straight line 30 of the first tread surface 26a (shown in Figure 3) and the maximum diagonal 36 of the second tread surface 27a are inclined in the same direction with respect to the tire axis. Furthermore, the angle θ7 of the maximum diagonal 36 of the second tread surface 27a with respect to the tire circumferential direction is, for example, 45° or less, and preferably 30 to 40°. The angle θ8 of the minimum diagonal 37 of the second crown block 27 with respect to the tire axis is, for example, 45° or less, and preferably 5 to 15°. However, the second crown block 27 is not limited to this embodiment.

The maximum length L10 of the second tread surface 27a of the second crown block 27 in the tire circumferential direction is preferably 130% to 150% of the length L9 (shown in Figure 2) of the first tread surface 26a of the first crown block 26 on the tire equator C. This ensures the circumferential rigidity of the second crown block 27 and improves traction performance on dry surfaces.

From the perspective of ensuring cornering performance on dry surfaces, it is desirable that the maximum length L11 of the second tread surface 27a of the second crown block 27 in the tire axial direction be 60% to 80% of the aforementioned length L10 of the second tread surface 27a of the second crown block 27.

The second crown block 27 preferably includes a crown recess 28 in which the side wall on the crown lateral groove 10 side is partially recessed. In a preferred embodiment, of the two second crown blocks 27 included in the second region 4B, one second crown block 27 includes the crown recess 28 on the first side A1 in the tire circumferential direction, and the other second crown block 27 includes the crown recess 28 on the second side A2 in the tire circumferential direction. This further improves snow performance.

As shown in Figure 2, the first crown block 26 and the second crown block 27 are each provided with a plurality of crown sipes 29. It is preferable that the crown sipes 29 are, for example, locally bent. Such crown sipes 29 can improve snow performance while maintaining the rigidity of the first crown block 26 and the second crown block 27. In this specification, "sipe" refers to a groove-like body with a small width (meaning a recess having a longitudinal direction), where the width between the two inner walls is 1.5 mm or less. The sipe may include a chamfered portion at the opening or a so-called flask bottom with an increased width at the bottom.

Figure 5 shows an enlarged view of one of the circumferential grooves 3 in Figure 1 (the circumferential groove 3 on the left side of Figure 1). As shown in Figure 5, the circumferential groove 3 includes connecting portions 15 to which the crown lateral grooves 10 are connected.

Figure 6 shows an enlarged view of one connection portion 15. In Figure 6, the connection portion 15 is marked with dots. As shown in Figure 6, each of the connection portions 15 includes a first edge 16, a second edge 17, and a third edge 18, which are separated from each other. The first edge 16 extends from the first side A1 of the connection portion 15 at an angle θ1 of 30° or less with respect to the tire axis. The second edge 17 and the third edge 18 are located on the second side A2 of the connection portion 15. Furthermore, the third edge 18 is located inward in the tire axis direction compared to the second edge 17.

The second edge 17 and the third edge 18 are inclined in opposite directions with respect to the tire circumferential direction and extend toward each other from the first side A1 toward the second side A2.

Furthermore, in this disclosure, the crown lateral groove 10 is connected to the first side A1 of the connection portion 15. This configuration means that, at least, the crown lateral groove 10 is connected to the connection portion 15 on the first side A1, rather than on the second edge 17 and the third edge 18. Also, the crown lateral groove 10 crosses the extension of the first edge 16. The groove width W2 of the circumferential groove 3 at the closest approach position where the second edge 17 and the third edge 18 are closest is smaller than the groove width W1 of the crown lateral groove 10 on the extension of the first edge 16. As a result, when driving on snow, the snow within the crown lateral groove 10 and the connection portion 15 moves towards the second edge 17 and the third edge 18 using the rotation of the tire, and is strongly compressed between these edges. Furthermore, the shearing of the generated snow columns by the first edge 16 provides a large reaction force (snow column shearing force), improving traction and braking performance on snow.

In this embodiment, the first edge 16, the second edge 17, and the third edge 18 each have groove walls arranged at an angle of 15° or less with respect to the tire radial direction (not shown). However, this disclosure is not limited to this embodiment, and these edges may, for example, be connected to chamfered surfaces arranged at an angle of 30 to 60° with respect to the tire radial direction.

In a plan view of the tread, the first edge 16 is configured as a linearly extending line segment. The length L5 of the first edge 16 (the so-called peripheral length along the sipe length) is, for example, 5% to 10% of the tread width TW (shown in Figure 1). Furthermore, the angle θ1 of the first edge 16 with respect to the tire axis is preferably 10 to 20°. Such a first edge 16 can provide a well-balanced snow column shear force in both the circumferential and axial directions of the tire.

In a plan view of the tread, the second edge 17 is constructed as a linearly extending line segment. The length L6 of the second edge 17 in the tire axial direction (the so-called peripheral length along the sipe length) is, for example, 80% to 120% of the length L5 of the first edge 16.

As shown in Figure 5, the first edge 16 and the second edge 17 extend in a direction that approaches each other from the tire equator C towards the tread edge Te. The angle θ2 between the first edge 16 and the second edge 17 is, for example, 30 to 40°. Furthermore, it is desirable that the minimum distance La between the first edge 16 and the second edge 17 is greater than the groove width W1 (shown in Figure 6). Specifically, it is desirable that the distance La is 130% to 170% of the groove width W1. This arrangement of the first edge 16 and the second edge 17 allows the snow within the connection portion 15 to be strongly compressed in the tire axial direction when driving on snow, and also suppresses snow from accumulating within the connection portion 15.

The third edge 18 is configured, for example, as part of the edge of a block adjacent to the tire equator C side of the circumferential groove 3. The angle θ3 between the second edge 17 and the third edge 18 is, for example, acute, preferably 60 to 80°, and more preferably 65 to 75°. Such second edges 17 and third edges 18 can firmly compact snow within the connection portion 15 and can prevent snow from becoming trapped within the connection portion 15.

As shown in Figure 6, the groove width W2 of the circumferential groove 3 is, for example, preferably 30% or more, more preferably 50% or more, preferably 90% or less, and more preferably 80% or less of the groove width W1 of the crown lateral groove 10. This makes it difficult for snow to accumulate in the connection portion 15, and excellent snow performance is maintained over time.

As shown in Figure 5, the circumferential groove 3 of this embodiment includes a plurality of convex groove portions 20 that are curved in a direction that protrudes toward the tread edge Te side. In this embodiment, the convex groove portions 20 and the aforementioned connecting portion 15 are arranged alternately in the circumferential direction of the tire. Furthermore, the convex groove portions 20 include a first groove portion 21 and a second groove portion 22. The first groove portion 21 is connected to the first side A1 of the connecting portion 15. The second groove portion 22 of the convex groove portion 20 is connected to a crown lateral groove 10 that is different from the crown lateral groove 10 connected to the aforementioned connecting portion 15. Such a convex groove portion 20, including the first groove portion 21 and the second groove portion 22, can strongly compress snow internally, further improving snow performance.

The groove width W3 at the point closest to the connection point 15 of the first groove 21 is preferably larger than the groove width W2 (shown in Figure 6). Specifically, the groove width W3 is 130% to 170% of the groove width W2. Such a first groove 21 helps to improve both handling stability on dry surfaces (hereinafter sometimes simply referred to as "handling stability") and snow performance in a balanced manner.

The convex groove section 20 includes, for example, a narrow section 20a in the central part of the tire's circumferential direction, where the groove width is smaller than that of other sections. The groove width W4 of the narrow section 20a is, for example, 80% to 120% of the groove width W2 (shown in Figure 6). Such a narrow section 20a can further compact the snow within the convex groove section 20 when driving on snow.

Figure 7 shows an enlarged view of the shoulder land portion 5 in Figure 1. The shoulder land portion 5 includes, for example, multiple shoulder blocks 45 separated by multiple shoulder lateral grooves 44 extending in the tire axial direction.

It is desirable that at least one of the shoulder lateral grooves 44 extends from the aforementioned connection portion 15 of the circumferential groove 3 toward the tread edge Te. Such shoulder lateral grooves 44, together with the connection portion 15, help to improve snow performance.

The shoulder block 45 preferably includes a shoulder recess 46 in which the side wall on the circumferential groove 3 side is partially recessed. Such a shoulder recess 46 can further improve snow performance.

The shoulder block 45 is provided with multiple shoulder sipes 47. It is desirable that the shoulder sipes 47 are locally bent. Such shoulder sipes 47 can improve snow performance while maintaining the rigidity of the shoulder block 45.

Although a tire according to one embodiment of this disclosure has been described in detail above, this disclosure is not limited to the specific embodiment described above and can be implemented in various modified forms.

[Note]
This disclosure includes the following aspects.

[Disclosure 1]
A tire having a tread portion,
The tread portion includes at least two circumferential grooves extending continuously in the circumferential direction of the tire, a plurality of crown lateral grooves connecting the two circumferential grooves, and a crown land portion divided between the two circumferential grooves.
The crown land portion alternately includes a first region and a second region, separated by the plurality of crown lateral grooves, in the circumferential direction of the tire.
The first region includes a first crown block having a first tread surface,
The second region includes at least one second crown block having a second tread, the second crown block being adjacent to the first crown block via the crown lateral groove,
In a plan view of the tread,
The first crown block is positioned such that the longest possible straight line that can be drawn on the first tread is less than 45° with respect to the tire axis.
The first tread has a maximum length L2 in the direction perpendicular to the maximum straight line that is 50% or less of the length L1 of the maximum straight line.
The second tread of the second crown block is a polygonal shape on which the maximum and minimum diagonals can be drawn to divide the second tread into two parts having 45% or more of its area.
The length of the maximum diagonal is 160% or less of the length of the minimum diagonal.
tire.
[Disclosure 2]
The tire according to Disclosure 1, wherein the length of the minimum diagonal is 60% or more of the length of the maximum diagonal.
[Disclosure 3]
The tire according to disclosure 1 or 2, wherein one of the second regions includes two or more of the second crown blocks.
[Disclosure 4]
The aforementioned first crown block is located on the tire equator,
The tire according to any one of disclosures 1 to 3, wherein the maximum length of the second crown block in the tire circumferential direction is 130% to 150% of the length of the first crown block on the tire equator.
[Disclosure 5]
The first crown block includes a main portion and sub-portions connected to both sides of the main portion in the tire axial direction.
The main part includes two edges extending parallel to each other,
The tire according to any one of disclosures 1 to 4, wherein the sub-part includes two edges extending toward each other toward the tire axial end of the first crown block.
[Disclosure 6]
The tire according to disclosure 5, wherein the angle between the two edges of the sub-part is 30 to 60°.
[Disclosure 7]
The tire according to any one of disclosures 1 to 6, wherein the maximum straight line of the first tread and the maximum diagonal of the second tread are inclined in the same direction with respect to the tire axis.

2 Tread section 3 Circumferential grooves 4 Crown surface 4A First area 4B Second area 10 Crown lateral grooves 26 First crown block 26a First tread 27 Second crown block 27a Second tread 30 Maximum straight length 36 Maximum diagonal length 37 Minimum diagonal length L1 Length of the maximum straight length L2 Maximum length in the direction perpendicular to the maximum straight length

Claims (6)

A tire having a tread portion,
The tread portion includes at least two circumferential grooves extending continuously in the circumferential direction of the tire, a plurality of crown lateral grooves connecting the two circumferential grooves, and a crown land portion divided between the two circumferential grooves.
The crown land portion alternately includes a first region and a second region, separated by the plurality of crown lateral grooves, in the circumferential direction of the tire.
The first region includes a first crown block having a first tread surface,
The second region includes at least one second crown block having a second tread, the second crown block being adjacent to the first crown block via the crown lateral groove,
In a plan view of the tread,
The first crown block is positioned such that the longest possible straight line that can be drawn on the first tread is less than 45° with respect to the tire axis.
The first tread has a maximum length L2 in the direction perpendicular to the maximum straight line that is 30% to 40% of the length L1 of the maximum straight line.
The second tread of the second crown block is a polygonal shape on which the maximum and minimum diagonals can be drawn to divide the second tread into two parts having 45% or more of its area.
The length of the maximum diagonal is 160% or less of the length of the minimum diagonal.
tire. A tire having a tread portion,
The tread portion includes at least two circumferential grooves extending continuously in the circumferential direction of the tire, a plurality of crown lateral grooves connecting the two circumferential grooves, and a crown land portion divided between the two circumferential grooves.
The crown land portion alternately includes a first region and a second region, separated by the plurality of crown lateral grooves, in the circumferential direction of the tire.
The first region includes a first crown block having a first tread surface,
The second region includes at least one second crown block having a second tread, the second crown block being adjacent to the first crown block via the crown lateral groove,
In a plan view of the tread,
The first crown block is positioned such that the longest possible straight line that can be drawn on the first tread is less than 45° with respect to the tire axis.
The first tread has a maximum length L2 in the direction perpendicular to the maximum straight line that is 50% or less of the length L1 of the maximum straight line.
The second tread of the second crown block is a polygonal shape on which the maximum and minimum diagonals can be drawn to divide the second tread into two parts having 45% or more of its area.
The length of the maximum diagonal is 160% or less of the length of the minimum diagonal.
The first crown block includes a main portion and sub-portions connected to both sides of the main portion in the tire axial direction.
The main part includes two edges extending parallel to each other,
The sub-part includes two edges that extend toward each other toward the tire axial end of the first crown block,
The angle between the two edges of the aforementioned sub-part is 30 to 60°.
tire. A tire having a tread portion,
The tread portion includes at least two circumferential grooves extending continuously in the circumferential direction of the tire, a plurality of crown lateral grooves connecting the two circumferential grooves, and a crown land portion divided between the two circumferential grooves.
The crown land portion alternately includes a first region and a second region, separated by the plurality of crown lateral grooves, in the circumferential direction of the tire.
The first region includes a first crown block having a first tread surface,
The second region includes at least one second crown block having a second tread, the second crown block being adjacent to the first crown block via the crown lateral groove,
In a plan view of the tread,
The first crown block is positioned such that the longest possible straight line that can be drawn on the first tread is less than 45° with respect to the tire axis.
The first tread has a maximum length L2 in the direction perpendicular to the maximum straight line that is 50% or less of the length L1 of the maximum straight line.
The second tread of the second crown block is a polygonal shape on which the maximum and minimum diagonals can be drawn to divide the second tread into two parts having 45% or more of its area.
The length of the maximum diagonal is 160% or less of the length of the minimum diagonal.
The aforementioned first crown block is located on the tire equator,
The maximum length of the second crown block in the tire circumferential direction is 130% to 150% of the length of the first crown block on the tire equator.
tire. The tire according to any one of claims 1 to 3, wherein the length of the minimum diagonal is 60% or more of the length of the maximum diagonal . The tire according to any one of claims 1 to 3, wherein one of the second regions includes two or more of the second crown blocks . The tire according to any one of claims 1 to 3, wherein the longest straight line of the first tread and the longest diagonal of the second tread are inclined in the same direction with respect to the tire axis .