Tire

Abstract

Provided is a tire capable of improving mud performance without deteriorating noise performance. The tire (1) is formed with a plurality of blocks (5) by longitudinal grooves (3) and transverse grooves (4). The plurality of blocks (5) at least includes a recessed block (6) having a recess (10) that is radially inward of the tread (5a) of the tire and radially outward of the groove bottom (4s) of the transverse groove (4). In the contact patch (2a), the ratio (Ar / At) of the total area (Ar) of the recesses (10) to the total area (At) of the treads (5a) of the plurality of blocks (5) is 10% to 20%.

Description

Technical Field

[0001] The present invention relates to a tire. Background Art

[0002] In Patent Document 1 described below, a pneumatic tire is described in which a first block and a second block are disposed adjacent to each other via a main groove in a tread portion. The main groove has a first groove portion and a second groove portion that are alternately arranged in the tire circumferential direction with respect to the first groove portion. The first block and the second block each have a recess formed by partially cutting off a corner between its tread surface and a wall surface. Such a pneumatic tire improves mud performance while maintaining noise performance.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-176881 Summary of the Invention

[0004] In recent years, there has been a desire to further improve mud performance without deteriorating noise performance.

[0005] The present invention has been made in view of the above actual situation, and its main object is to provide a tire capable of improving mud performance without deteriorating noise performance.

[0006] The tire of the present invention is a tire having a tread portion, in which a plurality of blocks are formed by longitudinal grooves and transverse grooves, and the plurality of blocks at least include a block with a recess. The block with the recess has a recess that is radially inner than the tread surface and radially outer than the bottom of the transverse groove. In the contact patch when the tire is assembled on a standard rim, filled with a standard internal pressure, and applied with a standard load and grounded on a plane with a camber angle of 0 degrees, the ratio (Ar / At) of the total area Ar of the recesses to the total area At of the tread surfaces of the plurality of blocks is 10% to 20%.

[0007] Preferably, in the contact patch, the ratio (Cr / Ct) of the total area Cr of the recesses in the tread crown portion to the total area Ct of the tread surfaces in the tread crown portion is greater than the ratio (Sr / St) of the total area Sr of the recesses in the tread shoulder portion to the total area St of the tread surfaces in the tread shoulder portion.

[0008] Preferably, the ratio (Cr / Ct) is 15% to 30%.

[0009] Preferably, the ratio (Sr / St) is 6% to 13%.

[0010] Preferably, the recess includes a chamfered portion formed at an edge of the tread surface.

[0011] The tire of the present invention preferably has a stepped recessed portion at the edge of the tread surface in the recess.

[0012] The tire of the present invention preferably has at least one siped formed in the block with the recess, the siped including a raised portion formed by the bottom of the siped bulging, and the recess including the raised portion.

[0013] The tire of the present invention preferably has at least one interrupted groove formed in the block with the recess, and the recess includes the interrupted groove.

[0014] The tire of the present invention preferably has a chamfered portion formed at the edge of the tread surface and a stepped recessed portion that is stepped and recessed at the edge of the tread surface. The total area Aa of the stepped recessed portion, the total area Ab of the raised portion, and the total area Ac of the chamfered portion within the ground contact surface satisfy the following formula (1).

[0015] Aa > Ab > Ac…(1)

[0016] The tire of the present invention preferably has a ratio (Ab / At) of the total area Ab of the raised portion to the total area At of the tread surfaces of the plurality of blocks of 3% or more within the ground contact surface.

[0017] The tire of the present invention preferably has a ratio (Ac / At) of the total area Ac of the chamfered portion to the total area At of the tread surfaces of the plurality of blocks of 1% or more within the ground contact surface.

[0018] By adopting the above structure, the present invention can improve the mud performance without deteriorating the noise performance. Description of the Drawings

[0019] Figure 1 is a developed view of the tread portion of an embodiment of the present invention.

[0020] Figure 2 is a developed view of the tread portion.

[0021] Figure 3 (a) and (b) are schematic cross-sectional views of the block with the recess for explaining the recess.

[0022] Figure 4 is Figure 2 an enlarged view of

[0023] Figure 5 is Figure 2 an enlarged view of

[0024] Reference Numeral Explanation

[0025] 1: Tire; 2a: Ground contact surface; 3: Longitudinal groove; 4: Transverse groove; 4s: Groove bottom; 5: Block; 5a: Tread surface; 6: Block with recess; 10: Recess. Detailed implementation mode

[0026] Hereinafter, an embodiment of the present invention will be described based on the drawings.

[0027] Figure 1 is an expanded view of the tread surface 2 of the tire 1 of this embodiment. As a preferred mode, in Figure 1 a pneumatic tire for a four-wheel drive passenger car is shown. However, the present invention can also be applied to tires 1 for light trucks, heavy loads, etc. In addition, the present invention can also be applied to other types of tires 1.

[0028] As Figure 1 shown, in the tread surface 2 of this embodiment, a plurality of blocks 5 are formed by longitudinal grooves 3 and transverse grooves 4.

[0029] The plurality of blocks 5 at least include a block 6 with a recess. The block 6 with a recess has a recess 10 that is radially inner than the tread surface 5a and radially outer than the groove bottom 4s of the transverse groove 4. Such a recess 10 exerts a shearing force on muddy road surfaces such as dirt roads and muddy roads. On the other hand, when driving on a dry asphalt road surface, pumping sound is generated by compressing air between the tire and the road surface.

[0030] Moreover, in this embodiment, within the ground contact surface 2a in the standard load state, the ratio (Ar / At) of the total area Ar of the recesses 10 to the total area At of the tread surfaces 5a of the plurality of blocks 5 is 10% to 20%. Since the ratio (Ar / At) is 10% or more, the shearing force on the muddy road surface becomes larger, and the muddy road performance can be improved. Since the ratio (Ar / At) is 20% or less, the pumping sound is suppressed from becoming larger, and the noise performance is maintained. In Figure 1 an example of the ground contact surface 2a in the standard load state is shown by diagonal lines.

[0031] The "standard load state" refers to a state in which a standard load is applied to the tire 1 in the standard state and the tire is grounded on a plane with a camber angle of 0 degrees. The "standard state" refers to a load-free state in which the tire 1 is assembled on a standard rim (not shown) and filled with a standard internal pressure.

[0032] The "standard load" refers to the load specified for each specification of the tire in the specification system including the specifications on which the tire is based. If it is JATMA, it represents the "maximum load capacity". If it is TRA, it represents the maximum value recorded in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". If it is ETRTO, it represents "LOAD CAPACITY".

[0033] The "standard rim" refers to the rim specified for the tire in the specification system including the specifications on which the tire is based. For example, in the case of JATMA, it is the "standard rim"; in the case of TRA, it is the "Design Rim"; and in the case of ETRTO, it is the "Measuring Rim". The "standard internal pressure" refers to the air pressure specified for each specification of the tire in the specification system including the specifications on which the tire is based. For example, in the case of JATMA, it is the "maximum air pressure"; in the case of TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in the case of ETRTO, it is the "INFLATION PRESSURE".

[0034] In the standard load state, the two outermost grounding positions in the tire axial direction of the ground contact surface 2a are determined as the tread ends Te, Te. In the standard state, the distance in the tire axial direction between the tread ends Te, Te is defined as the tread width TW. Unless otherwise specified, the dimensions of each part of the tire 1 are values measured in the standard state.

[0035] The longitudinal groove 3 refers to a groove with a minimum groove width of 4 mm or more and an angle relative to the tire circumferential direction of 45 degrees or less. In addition, the transverse groove 4 refers to a groove with a minimum groove width of 4 mm or more and extending at an angle relative to the tire circumferential direction exceeding 45 degrees. In addition, in this specification, the "groove" refers to a groove-shaped body with a groove width of 2 mm or more, which is distinguished from the later-described cut-shaped sipes with a width less than 2 mm.

[0036] The tread portion 2 is divided into a tread crown portion 2c and a tread shoulder portion 2s. In the present embodiment, the tread crown portion 2c is a region centered on the tire equator C and having a width La in the tire axial direction of 45% to 55% of the tread width TW. In the present embodiment, the tread shoulder portion 2s is a region disposed on both outer sides in the tire axial direction of the tread crown portion 2c and adjacent to the tread crown portion 2c.

[0037] The tread crown part 2c has a greater contact pressure during straight running than the tread shoulder part 2s. Therefore, by providing the recess 10 larger at the tread crown part 2c, a shearing force can be effectively exerted on a muddy road surface. In addition, it is considered that the pumping sound generated at the tread shoulder part 2s has a greater impact on the noise performance than the pumping sound generated at the tread crown part 2c. Therefore, preferably, within the contact surface 2a in the standard load state, the recess ratio (Cr / Ct) of the tread crown part 2c is greater than the recess ratio (Sr / St) of the tread shoulder part 2s. The recess ratio (Cr / Ct) is the ratio of the total area Cr of the recesses 10 in the tread crown part 2c to the total area Ct of the tread surfaces 5a of the blocks 5 in the tread crown part 2c. The recess ratio (Sr / St) is the ratio of the total area Sr of the recesses 10 in the tread shoulder part 2s to the total area St of the tread surfaces 5a of the blocks 5 in the tread shoulder part 2s.

[0038] In order to effectively exert the functions as described above, the recess ratio (Cr / Ct) of the tread crown part 2c is preferably 15% or more, more preferably 22% or more, and preferably 30% or less, more preferably 26% or less. In addition, the recess ratio (Sr / St) of the tread shoulder part 2s is preferably 6% or more, more preferably 10% or more, and preferably 13% or less, more preferably 12% or less.

[0039] Figure 2 is a developed view of the tread part 2. As Figure 2 shown, in the present embodiment, the longitudinal grooves 3 include a pair of crown longitudinal grooves 3A and a pair of shoulder longitudinal grooves 3B disposed on the outer side in the tire axial direction of each crown longitudinal groove 3A. In the present embodiment, the crown longitudinal grooves 3A and the shoulder longitudinal grooves 3B continuously extend in a zigzag shape in the tire circumferential direction. In addition, the longitudinal grooves 3 are not limited to such a shape.

[0040] In the present embodiment, the transverse grooves 4 include a crown transverse groove 4A, an intermediate transverse groove 4B, and a shoulder transverse groove 4C.

[0041] The crown transverse groove 4A of the present embodiment extends in a manner connected to the pair of crown longitudinal grooves 3A, 3A. The crown transverse groove 4A includes, for example, a first crown transverse groove 7a and a second crown transverse groove 7b, and the second crown transverse groove 7b is inclined at a greater angle with respect to the tire circumferential direction than the first crown transverse groove 7a. The first crown transverse groove 7a and the second crown transverse groove 7b are alternately provided in the tire circumferential direction.

[0042] The intermediate transverse groove 4B of the present embodiment extends in a manner that connects to the crown longitudinal groove 3A and the shoulder longitudinal groove 3B. The intermediate transverse groove 4B includes, for example, a first intermediate transverse groove 8a and a second intermediate transverse groove 8b, and the second intermediate transverse groove 8b is inclined at a larger angle with respect to the tire circumferential direction than the first intermediate transverse groove 8a. The first intermediate transverse groove 8a and the second intermediate transverse groove 8b are alternately arranged in the tire circumferential direction.

[0043] The shoulder transverse groove 4C of the present embodiment extends in a manner that connects to the shoulder longitudinal groove 3B and the tread end Te. The shoulder transverse groove 4C includes, for example, a first shoulder transverse groove 9a and a second shoulder transverse groove 9b, and the axial length of the second shoulder transverse groove 9b in the tire is larger than that of the first shoulder transverse groove 9a. The first shoulder transverse groove 9a and the second shoulder transverse groove 9b are alternately arranged in the tire circumferential direction.

[0044] In the present embodiment, the first crown transverse groove 7a, the first intermediate transverse groove 8a, and the shoulder transverse groove 4C include a groove bottom raised portion k formed by the groove bottom bulging.

[0045] Thus, the blocks 5 of the tread portion 2 each include a plurality of blocks, namely a crown block 5A, an intermediate block 5B, and a shoulder block 5C. The crown block 5A is demarcated by a pair of crown longitudinal grooves 3A, the first crown transverse groove 7a, and the second crown transverse groove 7b. The intermediate block 5B is demarcated by the crown longitudinal groove 3A, the shoulder longitudinal groove 3B, the first intermediate transverse groove 8a, and the second intermediate transverse groove 8b. The shoulder block 5C is demarcated by the shoulder longitudinal groove 3B, the tread end Te, the first shoulder transverse groove 9a, and the second shoulder transverse groove 9b.

[0046] Figure 3 (a) is a schematic cross-sectional view of the block 6 with a recess for explaining the recess 10 of the present embodiment. As Figure 3 shown in (a), the block 6 with a recess includes a tread surface 6a and a wall surface 6b, and the wall surface 6b is formed on the inner side in the tire radial direction relative to the tread surface 6a and extends from the groove bottom 4s of the longitudinal groove 3 ( Figure 2 shown) or the transverse groove 4.

[0047] In the present embodiment, the recess 10 includes a chamfered portion 11, a stepped portion 12, a raised portion ( Figure 3 shown in (b)) 13, and an interrupted groove ( Figure 2 shown) 14.

[0048] The chamfered portion 11 of the present embodiment is formed at the edge of the tread surface 6a. The chamfered portion 11 is formed, for example, as a surface that gently inclines toward the tire radial direction at the corner between the tread surface 6a and the wall surface 6b. In the present embodiment, the chamfered portion 11 extends from the tread surface 6a toward the inner side in the tire radial direction. The height h1 of the chamfered portion 11 in the tire radial direction is preferably 15% - 40% of the groove depth ha of the longitudinal groove 3 or the transverse groove 4 adjacent to the chamfered portion 11.

[0049] The stepped portion 12 of the present embodiment is formed in a stepped recessed manner at the edge of the tread surface 6a. The stepped portion 12 is formed to include, for example: at least one radial surface 12a that extends in the inner and outer directions of the tire radial direction; and at least one outer surface 12b that is connected to the radial surface 12a and extends along the tread surface 6a. In the present embodiment, the radial surface 12a is connected to the tread surface 6a. The height h2 in the tire radial direction between the outer surface 12b located at the outermost side in the tire radial direction of the stepped portion 12 and the tread surface 6a is preferably, for example, 25% to 35% of the groove depth ha of the longitudinal groove 3 or the transverse groove 4 adjacent to the stepped portion 12.

[0050] Figure 3 (b) is a schematic cross-sectional view for explaining another concave portion 10 of the concave portion of the present embodiment and the block 6 with the concave portion. As Figure 3 shown in (b), the block 6 with the concave portion of the present embodiment is provided with a siped 15. One end of the siped 15 terminates, for example, within the tread surface 6a, and the other end is connected to the transverse groove 4. Such a siped 15 suppresses a decrease in the rigidity of the block 5. In addition, the siped 15 is not limited to such a manner, and both ends of the siped 15 may communicate with the longitudinal groove 3 or the transverse groove 4, or both ends of the siped 15 may terminate within the tread surface 6a.

[0051] The raised portion 13 of the present embodiment is a portion where the bottom 15s of the siped 15 bulges. Such a raised portion 13 suppresses the siped 15 from opening significantly when in contact with the ground, and helps to improve the scraping force against soil harder than muddy ground. The height h3 of the raised portion 13 is preferably 30% to 60% of the depth da of the siped 15.

[0052] In addition, a plurality of raised portions 13 of the present embodiment are provided with a gap 16 therebetween. In the present embodiment, two raised portions 13 are provided in one siped 15. The sum (ΣL3) of the lengths L3 of each raised portion 13 is preferably 40% to 80% of the length Lb of the siped 15.

[0053] As Figure 2 shown, the interrupted groove 14 of the present embodiment is a groove that extends from the longitudinal groove 3 or the transverse groove 4 and terminates within the block 6 with the concave portion. Such an interrupted groove 14 can also improve the shearing force against muddy ground. The interrupted groove 14 includes, for example, an enlarged portion 14a whose groove width gradually increases from its inner end 14i toward the longitudinal groove 3 or the transverse groove 4. Such an enlarged portion 14a can smoothly discharge the soil accumulated therein to the longitudinal groove 3 or the transverse groove 4.

[0054] As Figure 1 shown, preferably, within the ground contact surface 2a in the standard load state, the total area Aa of the stepped portions 12, the total area Ab of the raised portions 13, and the total area Ac of the chamfered portions 11 satisfy the following formula (1).

[0055] Aa > Ab > Ac…(1)

[0056] Compared with the raised portion 13, the stepped portion 12 exerts a greater shearing force on muddy ground. In addition, compared with the chamfered portion 11, the raised portion 13 has a greater scraping force on soil. Therefore, if specified as in the above formula (1), the muddy ground performance and the noise performance can be improved in a balanced manner.

[0057] In order to more effectively exert the above-described effects, in the ground contact surface 2a in the standard load state, the ratio (Ab / At) of the total area Ab of the raised portions 13 to the total area At of the tread surfaces 5a of the plurality of blocks 5 is preferably 3% or more, and more preferably 5% or more. From the same viewpoint, the ratio (Ac / At) of the total area Ac of the chamfered portions 11 to the total area At of the tread surfaces 5a of the plurality of blocks 5 is preferably 1% or more, and more preferably 2.5% or more. In addition, the ratio (Ab / At) is preferably 11% or less, and more preferably 9% or less. Similarly, the ratio (Ac / At) is preferably 5% or less, and more preferably 3.5% or less.

[0058] Figure 4 is Figure 2 an enlarged view of the tread portion 2. As Figure 4 shown, the concave portion-provided block 6 of the present embodiment constitutes the crown block 5A, the intermediate block 5B, and the shoulder block 5C. In addition, the concave portion-provided block 6 is not limited to such a manner. For example, it may be a manner of constituting only the crown block 5A, or may constitute the crown block 5A and the intermediate block 5B.

[0059] In the crown block 5A of the present embodiment, a chamfered portion 11, a stepped portion 12, a raised portion 13, and an interrupted groove 14 are provided. The stepped portion 12 of the crown block 5A includes a pair of longitudinal groove stepped portions 12A respectively adjacent to a pair of crown longitudinal grooves 3A and a transverse groove stepped portion 12B adjacent to the second crown transverse groove 7b. Each of the longitudinal groove stepped portions 12A of the present embodiment has one outer-facing surface 12b. The transverse groove stepped portion 12B of the present embodiment has two outer-facing surfaces 12b having different positions in the tire radial direction.

[0060] Two raised portions 13 of the crown block 5A are provided on one sipe 15 communicating with a pair of crown longitudinal grooves 3A. The interrupted groove 14 of the crown block 5A is provided so as to communicate with one of the crown longitudinal grooves 3A. The chamfered portion 11 of the crown block 5A is provided so as to be connected to the interrupted groove 14 and the crown longitudinal groove 3A.

[0061] The intermediate block 5B of the present embodiment includes: a first intermediate block 17A provided with a stepped portion 12 and a raised portion 13; and a second intermediate block 17B provided with a stepped portion 12, a raised portion 13, and an interrupted groove 14. The first intermediate block 17A and the second intermediate block 17B are alternately provided in the tire circumferential direction.

[0062] The step portion 12 of the first intermediate block 17A includes: an intermediate first step portion 12C adjacent to the first intermediate transverse groove 8a; and an intermediate second step portion 12D adjacent to the second intermediate transverse groove 8b. The intermediate first step portion 12C has an outward-facing surface 12b. The intermediate second step portion 12D has two outward-facing surfaces 12b with different positions in the tire radial direction. Two of the raised portions 13 of the first intermediate block 17A are respectively arranged in the two cutter grooves 15, 15 provided in the first intermediate block 17A.

[0063] Figure 5 is Figure 2 an enlarged view of the tread portion 2 of. As Figure 5 shown, the step portion 12 of the second intermediate block 17B includes, for example, an intermediate third step portion 12E, an intermediate fourth step portion 12F, and an intermediate fifth step portion 12G.

[0064] The intermediate third step portion 12E of the present embodiment is adjacent to the first intermediate transverse groove 8a. The intermediate third step portion 12E has, for example, an outward-facing surface 12b. The intermediate fourth step portion 12F of the present embodiment is arranged on the side opposite to the intermediate third step portion 12E in the tire circumferential direction. The intermediate fourth step portion 12F includes a first portion 20a adjacent to the second intermediate transverse groove 8b, a second portion 20b adjacent to the crown longitudinal groove 3A, and a third portion 20c adjacent to the shoulder longitudinal groove 3B. The first portion 20a to the third portion 20c each have an outward-facing surface 12b, and these outward-facing surfaces 12b are connected. The intermediate fifth step portion 12G of the present embodiment is adjacent to the shoulder longitudinal groove 3B. The intermediate fifth step portion 12G has, for example, two outward-facing surfaces 12b with different positions in the tire radial direction.

[0065] Two of the raised portions 13 of the second intermediate block 17B are respectively arranged in the two cutter grooves 15, 15 provided in the second intermediate block 17B. The interruption groove 14 of the second intermediate block 17B is provided in a manner that communicates with the shoulder longitudinal groove 3B. The interruption groove 14 of the second intermediate block 17B is connected to the third portion 20c of the intermediate fourth step portion 12F.

[0066] In the shoulder block 5C of the present embodiment, a step portion 12 and a raised portion 13 are provided. The shoulder block 5C includes: a first shoulder block 18A provided with one step portion 12; and a second shoulder block 18B provided with two step portions 12. The first shoulder block 18A and the second shoulder block 18B are alternately arranged in the tire circumferential direction.

[0067] The step portion 12 of the first shoulder block 18A is adjacent to the shoulder longitudinal groove 3B. The step portion 12 of the first shoulder block 18A has three outward-facing surfaces 12b with different positions in the tire radial direction. The three outward-facing surfaces 12b are arranged in the tire circumferential direction. Two of the raised portions 13 of the first shoulder block 18A are respectively arranged in the two cutter grooves 15, 15 provided in the first shoulder block 18A.

[0068] The stepped portion 12 of the second shoulder block 18B includes: a first shoulder stepped portion 12H adjacent to the shoulder longitudinal groove 3B; and a second shoulder stepped portion 12I adjacent to the tread end Te. The first shoulder stepped portion 12H has three outward-facing surfaces 12b with different positions in the tire radial direction. The three outward-facing surfaces 12b are arranged in the tire circumferential direction. The second shoulder stepped portion 12I has three outward-facing surfaces 12b with different positions in the tire radial direction. The three outward-facing surfaces 12b are arranged in the tire axial direction.

[0069] Two of the raised portions 13 of the second shoulder block 18B are respectively arranged in the two knife grooves 15, 15 provided in the second shoulder block 18B.

[0070] As described above, a particularly preferred embodiment of the present invention has been described in detail, but the present invention is not limited to the illustrated embodiment and can be implemented in various forms.

[0071]

Example

[0072] Based on the specifications in Table 1, a tire for a four-wheel drive vehicle with a size of 265 / 70R17 having a Figure 1 basic tread pattern was trial-produced, and the mud performance and noise performance of each test tire were tested. The main common specifications and test methods of each test tire are as follows.

[0073] <Mud performance>

[0074] Each test tire was installed on all the wheels of a four-wheel drive vehicle with a displacement of 5300 cc under the following conditions. Then, the driver was tested to drive the vehicle on a test route on a muddy road surface, and the driving characteristics related to traction, driving stability, turning performance, etc. at this time were evaluated by the senses. The results are expressed as a score with Comparative Example 1 as 100. The larger the value, the better.

[0075] Rim: 17×8.0J (all wheels)

[0076] Inner pressure: 410 kPa (front wheels), 520 kPa (rear wheels)

[0077] La / TW: 50%

[0078] <Noise performance>

[0079] In the test route on a dry asphalt road surface, the in-vehicle noise was measured when the test vehicle was driving at a speed of 60 km / h. The results were judged by the magnitude of the noise (db) and expressed as an index with the value of Comparative Example 1 as 100. The smaller the value, the better the noise performance.

[0080] The test results and the like are shown in Table 1.

[0081]

Table 1

[0082] Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Ratio (Ar / At) (%) 5 25 20 15 17 10 Ratio (Cr / Ct) (%) 8 25 30 15 30 15 Ratio (Sr / st) (%) 4 30 13 13 6 6 Muddy ground performance [Rating: the larger the value, the better] 100 120 120 120 115 110 Noise performance [Index: the smaller the value, the better] 100 115 105 100 95 95

[0083] It can be confirmed from the test results that the tire of the example can maintain the noise performance and improve the mud performance compared with the tire of the comparative example.

Claims

1. A tire, the tire having a tread face, wherein, In the tread surface portion, a plurality of blocks are formed by longitudinal grooves and transverse grooves. The plurality of blocks at least include a block with a recess. The block with a recess has a recess that is radially inner than the tread surface and radially outer than the groove bottom of the transverse groove. In the contact patch when the tire is assembled on a standard rim, filled with a standard internal pressure, and subjected to a standard load and grounded on a plane with a camber angle of 0 degrees, the ratio (Ar / At) of the total area Ar of the recesses to the total area At of the tread surfaces of the plurality of blocks is 10% to 20%. The tread surface portion is divided into a tread crown portion and a tread shoulder portion. The tread crown portion is a region centered on the tire equator and having a width in the tire axial direction of 50% of the tread width. In the contact patch, the ratio (Cr / Ct) of the total area Cr of the recesses provided on the blocks in the tread crown portion to the total area Ct of the tread surfaces of the tread crown portion is greater than the ratio (Sr / St) of the total area Sr of the recesses provided on the blocks in the tread shoulder portion to the total area St of the tread surfaces of the tread shoulder portion. The recesses include a chamfered portion formed at the edge of the tread surface, a stepped portion that is stepped and recessed at the edge of the tread surface, a raised portion formed by the raised bottom of a siped groove, and an interrupted groove that extends from the longitudinal groove or the transverse groove and terminates within the block with a recess.

2. The tire according to claim 1, wherein The ratio (Cr / Ct) is 15% to 30%.

3. The tire according to claim 1 or 2, wherein, The ratio (Sr / St) is 6% to 13%.

4. The tire according to claim 1 or 2, wherein, The block with a recess is formed with at least one siped groove, and the siped groove includes a raised portion formed by the raised bottom of the siped groove.

5. The tire according to claim 1 or 2, wherein, The block with a recess is formed with at least one interrupted groove.

6. The tire according to claim 4, wherein, In the contact patch, the total area Aa of the stepped portions, the total area Ab of the raised portions, and the total area Ac of the chamfered portions satisfy the following formula (1): Aa > Ab > Ac... (1).

7. The tire according to claim 4, wherein, In the contact patch, the ratio (Ab / At) of the total area Ab of the raised portions to the total area At of the tread surfaces of the plurality of blocks is 3% or more.

8. The tire according to claim 1 or 2, wherein, In the contact patch, the ratio (Ac / At) of the total area Ac of the chamfered portions to the total area At of the tread surfaces of the plurality of blocks is 1% or more.

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