Pneumatic tire

Abstract

To provide a pneumatic tire which can reduce air column resonance sound while suppressing deterioration of contact area at the time of new one.SOLUTION: A pneumatic tire arranges a plurality of resonators 4 including on a land part 3 partitioned between a first circumferential direction main groove 2a and a second circumferential direction main groove 2b adjacent to the first circumferential direction main groove in a tire width direction: sub grooves which are terminated in the land part; and branch grooves which communicate with the sub grooves and the circumferential main grooves. The branch groove includes: a first branch groove which communicates an end of the sub groove at one side in a tire circumferential direction with the first circumferential main groove; and a second branch groove which communicates an end of the sub groove at the other side in the tire circumferential direction with the second circumferential main groove. An expanded width part whose groove width is larger than that at an opening part on a tread surface 1 is formed at at least a part in a groove depth direction of the sub groove at a portion that is at least a part in an extension direction of the sub groove. An extension length of the first branch groove and an extension length of the second branch groove are respectively longer than length of the sub groove in the tire circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art In the past, in order to suppress uneven wear of a pneumatic tire while reducing air column resonance noise, it has been proposed to provide a resonator having a hidden groove portion on the tread surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 117090 Brochure Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, the provision of the resonator reduces the contact area. In the later stages of wear, the groove depth becomes shallower due to wear, ensuring the rigidity of the land portion, so the impact of the reduction in the contact area is relatively small, but from the time of new product to the middle stage of wear, the groove depth remains deep, so the impact of the reduction in the contact area is relatively large, and there is a risk of a decrease in maneuverability such as handling stability due to the decrease in rigidity of the land portion decreasing.

[0005] Therefore, an object of the present invention is to provide a pneumatic tire that can reduce air column resonance noise while suppressing a decrease in the contact area when new. [Means for solving the problem]

[0006] (1) A pneumatic tire having a plurality of circumferential main grooves extending in the tire circumferential direction on a tread surface, A plurality of land portions are defined between a tread edge and the circumferential main groove or between the circumferential main grooves, A land portion partitioned between a first circumferential main groove and a second circumferential main groove adjacent to the first circumferential main groove in the tire width direction is provided with a plurality of resonators, the resonators including a sub-groove terminating within the land portion and a branch groove connecting the sub-groove and the circumferential main groove, the branch groove has a first branch groove connecting an end of the sub groove on one side in the tire circumferential direction to the first circumferential main groove, and a second branch groove connecting an end of the sub groove on the other side in the tire circumferential direction to the second circumferential main groove, the first branch groove has a first circumferential portion extending from one end of the sub groove in the tire circumferential direction to one side in the tire circumferential direction, and a first widthwise portion extending from the one end of the first circumferential portion in the tire circumferential direction to communicate with the first circumferential main groove, the second branch groove has a second circumferential portion extending from an end of the sub groove on the other side in the tire circumferential direction to the other side in the tire circumferential direction, and a second widthwise portion extending in the tire width direction from the end of the second circumferential portion on the other side in the tire circumferential direction to communicate with the second circumferential main groove, A widened portion having a groove width larger than the groove width at an opening portion to the tread surface is formed in at least a part of the extension direction of the sub-groove and at least a part of the groove depth direction of the sub-groove, A pneumatic tire, wherein an extension length of the first branch groove and an extension length of the second branch groove are each longer than a length of the sub groove in a tire circumferential direction.

[0007] Here, "tread surface" refers to the area of ​​the outer surface of the tread extending around the entire circumference of the tire that comes into contact with the road when the tire is mounted on an applicable rim, inflated to the specified internal pressure, and subjected to the maximum load. "Tread edge" refers to both ends in the tire width direction of the contact surface that comes into contact with the road when the tire is mounted on an applicable rim, inflated to the specified internal pressure, and subjected to the maximum load. Additionally, the terms "circumferential main groove," "first circumferential main groove," and "second circumferential main groove" refer to grooves that extend in the circumferential direction of the tire and have a groove width (opening width) of 2 mm or more under the standard condition when the tire is mounted on an applicable rim, inflated to a specified internal pressure, and no load is applied. Additionally, the term "extension length of the first (second) branch groove" refers to the length along the extension direction of the first (second) branch groove, whereas the term "length of the sub groove in the tire circumferential direction" refers to the length of the sub groove in the tire circumferential direction when projected in the tire width direction. Additionally, the "length of the sub groove in the tire circumferential direction" refers to the length of the sub groove in the tire circumferential direction on the tread surface when the tire is new.

[0008] Here, "applicable rim" refers to the standard rim (Measuring Rim in the ETRTO STANDARDS MANUAL, Design Rim in the TRA YEAR BOOK) for the applicable size that is described or will be described in the future in the industrial standards valid in the region where the tire is produced and used, such as the JATMA YEAR BOOK of JATMA (Japan Automobile Tire Manufacturers Association) in Japan, the STANDARDS MANUAL of ETRTO (The European Tyre and Rim Technical Organisation) in Europe, and the YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States (in other words, the above "rim" includes not only current sizes but also sizes that may be included in the above industrial standards in the future. An example of "sizes that will be described in the future" is the size described as "FUTURE DEVELOPMENTS" in the 2013 edition of the ETRTO STANDARDS MANUAL.), however, in the case of a size not described in the above industrial standards, it refers to a rim with a width that corresponds to the bead width of the tire. In addition, "prescribed internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating as stated in the above JATMA YEAR BOOK, etc., and in the case of a size not stated in the above industrial standards, "prescribed internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tire is mounted. Furthermore, "maximum load" refers to the load corresponding to the above maximum load capacity.

[0009] (2) The pneumatic tire according to (1), wherein the resonator is provided on the outer land portion when mounted on a vehicle.

[0010] (3) having only three of the circumferential main grooves; The first circumferential main groove is located on an outer side when mounted on a vehicle, and the second circumferential main groove and a third circumferential main groove adjacent to the outer side of the second circumferential main groove in the tire width direction are located on an inner side when mounted on a vehicle, The pneumatic tire described in (2), wherein the resonator is provided in an outer central land portion that is located on the outer side when mounted on a vehicle, adjacent to the inner side in the tire width direction of the outermost land portion when mounted on a vehicle, which is defined by a tread edge and the first circumferential main groove, and is defined between the first circumferential main groove and the second circumferential main groove.

[0011] (4) The pneumatic tire according to (2) or (3), further comprising an inner resonator in at least one of the land portions on the inner side when mounted on a vehicle, the inner resonator including an inner sub-groove terminating within the land portion and only one inner branch groove connecting the inner sub-groove and the circumferential main groove. Effect of the Invention

[0012] According to the present invention, it is possible to provide a pneumatic tire that can reduce air column resonance noise while suppressing a decrease in the contact area when the tire is new. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing a tread pattern of a pneumatic tire according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining a resonator. [Diagram 3] 3 is a cross-sectional view of FIG. 2 taken along line aa. [Figure 4] 2. This is a cross-sectional view taken along line bb in FIG. [Diagram 5] This is a cross-sectional view taken along the line c-c of Figure 2. [Figure 6] FIG. 1 is a diagram illustrating an example of an arrangement of communication devices. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The internal structure of a pneumatic tire (hereinafter, simply referred to as a "tire") according to one embodiment of the present invention can be the same as that of a conventional tire, and therefore a detailed description will be omitted. Meanwhile, as one example, the tire can include a pair of bead portions, a carcass that spans between the pair of bead portions in a toroidal shape, and a belt that is disposed on the tire radial outer side of the crown portion of the carcass.

[0015] 1 is a diagram showing a tread pattern of a pneumatic tire according to one embodiment of the present invention. In the following description, dimensions and the like refer to dimensions in the above-mentioned reference state unless otherwise specified.

[0016] As shown in Fig. 1, this tire has a plurality of circumferential main grooves 2 extending in the tire circumferential direction on a tread surface 1. In the illustrated example, this tire has only three circumferential main grooves 2a, 2b, and 2c, with only one circumferential main groove (first circumferential main groove 2a) located on the outer side when mounted on a vehicle (a tire width direction half of the outer side when mounted on a vehicle, with the tire equatorial plane CL as a boundary), and only two circumferential main grooves (a second circumferential main groove 2b adjacent to the first circumferential main groove 2a in the tire width direction and a third circumferential main groove 2c located on the innermost side when mounted on a vehicle and located on the outer side of the second circumferential main groove 2b in the tire width direction) located on the inner side when mounted on a vehicle (a tire width direction half of the inner side when mounted on a vehicle, with the tire equatorial plane CL as a boundary).

[0017] The circumferential main groove 2 preferably extends continuously in the tire circumferential direction. In the illustrated example, the circumferential main groove extends linearly in the tire circumferential direction, but may extend in a zigzag or curved manner. The groove width (opening width) of the circumferential main groove 2 is not particularly limited, but may be, for example, 8.0 to 12 mm. The groove depth (maximum depth) of the circumferential main groove 2 is not particularly limited, but may be, for example, 6 to 9 mm.

[0018] In addition, this tire has a plurality of (four in the illustrated example) land portions 3 defined between the tread edge TE and the circumferential main grooves 2 (2a, 2c) or between the circumferential main grooves (between 2a, 2b and between 2b, 2c). On the outer side when mounted on the vehicle, which is bounded by the tire equatorial plane CL, an outermost land portion 3a when mounted on the vehicle is defined between the tread edge TE and the circumferential main groove 2a, and an outer central land portion 3b adjacent to the outermost land portion 3a when mounted on the vehicle on the inner side in the tire width direction is defined between the first circumferential main groove 2a and the second circumferential main groove 2b. On the outer side when mounted on the vehicle, which is bounded by the tire equatorial plane CL, an innermost land portion 3d when mounted on the vehicle is defined between the tread edge TE and the circumferential main groove 2c, and an inner central land portion 3c adjacent to the innermost land portion 3d when mounted on the vehicle on the inner side in the tire width direction is defined between the second circumferential main groove 2b and the third circumferential main groove 2c.

[0019] First, the configuration in the outer central land portion 3b will be described. FIG. 2 is a diagram for explaining the resonators. As shown in FIG. 1 and FIG. 2, the tire is provided with a plurality of resonators 4 in the outer central land portion 3b, including a sub-groove 4a terminating in the outer central land portion 3b, and branch grooves 4b, 4c connecting the sub-groove 4a and the circumferential main groove 2 (2a, 2b). The first branch groove 4b connects the end of the sub-groove 4a on one side in the tire circumferential direction to the first circumferential main groove 2a. The second branch groove 4c connects the end of the sub-groove 4a on the other side in the tire circumferential direction to the second circumferential main groove 2b. As shown in the figure, the plurality of resonators 4 are arranged at a predetermined pitch interval in the tire circumferential direction.

[0020] As shown in Fig. 1, the sub groove 4a extends substantially in the tire circumferential direction. The length of the sub groove 4a in the tire circumferential direction is not particularly limited, but may be, for example, 25 to 45 mm. The groove width (opening width) (maximum groove width when measured in the tire width direction) of the sub groove 4a is not particularly limited, but may be, for example, 3 to 5 mm. The groove depth (maximum depth) of the sub groove 4a is not particularly limited, but may be, for example, 4 to 7.5 mm.

[0021] The first branch groove 4b has a first circumferential portion 4b1 extending from one end of the sub groove 4a in the tire circumferential direction to one side in the tire circumferential direction, and a first widthwise portion 4b2 extending from the end of the first circumferential portion 4b1 in the tire circumferential direction to the other side in the tire circumferential direction and communicating with the first circumferential main groove 2a. The second branch groove 4c has a second circumferential portion 4c1 extending from the end of the sub groove 4a in the tire circumferential direction to the other side in the tire circumferential direction, and a second widthwise portion 4c2 extending from the end of the second circumferential portion 4c1 in the tire circumferential direction to the other side in the tire circumferential direction and communicating with the second circumferential main groove 2b.

[0022] The groove width (opening width) of the first branch groove 4b is not particularly limited, but may be, for example, 0.5 to 1 mm. The groove depth (maximum depth) of the first branch groove 4b is not particularly limited, but may be, for example, 6 to 8 mm. The first circumferential portion 4b1 is not particularly limited, but may be inclined at an inclination angle of 10° or less with respect to the tire circumferential direction. The first widthwise portion 4b2 is not particularly limited, but may be inclined at an inclination angle of 30 to 50° with respect to the tire width direction. The groove width (opening width) of the second branch groove 4c is not particularly limited, but may be, for example, 0.5 to 1 mm. The groove depth (maximum depth) of the second branch groove 4c is not particularly limited, but may be, for example, 4 to 6 mm. The second circumferential portion 4c1 is not particularly limited, but may be inclined at an inclination angle of 10° or less with respect to the tire circumferential direction. The second width direction portion 4c2 may be inclined at an inclination angle of 30 to 50° with respect to the tire width direction, but is not particularly limited thereto. The extension length of the first branch groove 4b may be, for example, 30 to 50 mm in a range longer than the tire circumferential length of the sub groove 4a. The extension length of the second branch groove 4c may be, for example, 30 to 50 mm in a range longer than the tire circumferential length of the sub groove 4a.

[0023] Fig. 3 is a cross-sectional view taken along line aa in Fig. 2, and Fig. 4 is a cross-sectional view taken along line bb in Fig. 2. As shown in Figs. 3 and 4, a widened portion 4d having a groove width larger than the groove width at an opening portion to the tread surface 1 is formed in at least a part of the extension direction of the sub-groove 4a and at least a part of the groove depth direction of the sub-groove 4a. In this example, no widened portion is provided in the cross-sectional view taken along line aa in Fig. 2 shown in Fig. 3, and a widened portion 4d is provided in the cross-sectional view taken along line bb in Fig. 2 shown in Fig. 4.

[0024] In the location of the cross section aa in FIG. 2 shown in FIG. 3, the groove width gradually decreases from the outer side toward the inner side in the tire radial direction. In this location, the ratio w2 / w1 of the groove width w2 at the groove bottom 4g to the opening width w1 can be set appropriately. The groove depth h1 in this location can be set appropriately.

[0025] As shown in Fig. 4, at the location of the bb cross section of Fig. 2 shown in Fig. 4, a constant groove width portion 4e extending from the tread surface 1, where the groove width is the same as the opening width, toward the tire radial direction inward, and a widened portion 4d extending from the constant groove width portion 4e toward the tire radial direction inward to the groove bottom are formed. In the illustrated example, the widened portion 4d is such that the groove width gradually increases from the outer side to the inner side in the tire radial direction to the maximum groove width position on the constant groove width portion 4e side, and the groove width gradually decreases from the outer side to the inner side in the tire radial direction from the maximum groove width position to the groove bottom 4f. On the other hand, the widened portion 4d may have various cross-sectional shapes as long as it is a portion where the groove width is larger than the groove width at the opening to the tread surface 1, and is not limited to the above example.

[0026] At the location of the bb cross section of FIG. 2 shown in FIG. 4, the ratio w4 / w3 of the groove width w4 at the groove bottom 4f to the opening width w3 can be set as appropriate. Also, the ratio w3 / w5 of the opening width w3 to the groove width w5 at the maximum groove width position can be set as appropriate. The groove depth h2 at that location can be set as appropriate. The ratio h21 / h2 of the depth direction length h21 of the constant groove width portion 4e to the groove depth h2 can be set as appropriate. Also, the ratio h22 / h2 of the depth direction length h22 of the widened portion 4d to the groove depth h2 can be set as appropriate. Also, the ratio h2 / h1 can be set as appropriate.

[0027] As shown in FIG. 5, even in the location of the cc cross section of FIG. 2 shown in FIG. 5 (i.e., the second branch groove 4c), at least a part of the groove depth direction of the second branch groove 4c has a widened portion 4i having a groove width larger than the groove width at the opening to the tread surface 1. A constant groove width portion 4h having the same groove width as the opening width extending from the tread surface 1 to the tire radially inward, and a widened portion 4i extending from the constant groove width portion 4h to the tire radially inward to the groove bottom are formed. In the illustrated example, the widened portion 4i has a groove width that gradually increases from the outer side to the inner side in the tire radial direction to the groove width maximum position on the constant groove width portion 4h side, and the groove width gradually decreases from the outer side to the inner side in the tire radial direction from the groove width maximum position to the groove bottom. On the other hand, the widened portion 4i may have various cross-sectional shapes as long as it is a portion having a groove width larger than the groove width at the opening to the tread surface 1, and is not limited to the above example.

[0028] At the location of the cc cross section of FIG. 2 shown in FIG. 5, the ratio w7 / w6 of the groove width w7 at the groove bottom 4j to the opening width w6 can be set as appropriate. Also, the ratio w6 / w8 of the opening width w6 to the groove width w8 at the maximum groove width position can be set as appropriate. The groove depth h3 at that location can be set as appropriate. The ratio h31 / h3 of the depth direction length h31 of the constant groove width portion 4h to the groove depth h3 can be set as appropriate. Also, the ratio h32 / h3 of the depth direction length h32 of the widened portion 4i to the groove depth h3 can be set as appropriate. Also, the ratio h3 / h1 can be set as appropriate. The first branch groove 4b may have a cross-sectional shape similar to that described for the second branch groove 4c.

[0029] Here, the extension length of the first branch groove 4b and the extension length of the second branch groove 4c are each longer than the length of the sub groove 4a in the tire circumferential direction. Although not particularly limited, for example, the extension length of the first branch groove 4b and the extension length of the second branch groove 4c can each be 1.05 to 1.2 times the length of the sub groove 4a in the tire circumferential direction. In addition, the negative ratio (the ratio of the total groove area to the area of ​​the land part when it is assumed that there is no groove) of the outer central land part 3b provided with the multiple resonators 4 is not particularly limited, but can be, for example, 15 to 25%.

[0030] In this example, a widthwise sipe 6 extending in the tire width direction is disposed between each of two circumferentially adjacent first branch grooves 4b (in the illustrated example, just near the center). Also, a widthwise sipe 5 extending in the tire width direction is disposed between each of two circumferentially adjacent second branch grooves 4c (in the illustrated example, just near the center).

[0031] Next, the configuration of the outermost land portion 3a when mounted on a vehicle will be described. In this example, in the outermost land portion 3a when mounted on a vehicle, the widthwise sipes 7 extending from the tread edge TE toward the inner side in the tire width direction and communicating with the circumferential main groove 2a and the widthwise sipes 8 extending from the tread edge TE toward the inner side in the tire width direction and terminating in the outermost land portion 3a when mounted on a vehicle are alternately arranged in the tire circumferential direction. In this example, no groove is provided in the outermost land portion 3a when mounted on a vehicle, which can increase the rigidity of the land portion and improve the steering stability. As shown in the figure, it is preferable that the width in the tire width direction of the outermost land portion 3a when mounted on a vehicle is the largest among all land portions 3. This is because the rigidity of the land portion can be increased to improve the steering stability.

[0032] Next, the configuration of the inner central land portion 3c will be described. The inner central land portion 3c further includes an inner resonator 9 including an inner sub-groove 9a that terminates in the inner central land portion 3c and only one inner branch groove 9b that connects the inner sub-groove 9a and the third circumferential main groove 3c. A plurality of inner resonators 9 are arranged at intervals in the tire circumferential direction. The tire circumferential length of the sub-groove 4a is not particularly limited, but may be, for example, 140 to 170% of the tire circumferential length of the inner sub-groove 9a. In the illustrated example, a plurality of widthwise sipes 10 extending from the second circumferential main groove 2b at an angle with respect to the tire width direction are provided at intervals in the tire circumferential direction.

[0033] Next, the configuration of the innermost land portion 3d when mounted on a vehicle will be described. In the illustrated example, two rows of grooves 11 are arranged in the innermost land portion 3d when mounted on a vehicle. In the illustrated example, the grooves 11 are rhombic in plan view, but the shape can be various. The grooves 11 in one row and the grooves 11 in the other row are arranged with a phase shift in the tire circumferential direction so that they do not have overlapping portions when projected in the tire width direction. This makes it possible to balance the rigidity. By forming such grooves 11, the rigidity of the innermost land portion 3d when mounted on a vehicle can be moderately relaxed to improve ride comfort and wear resistance. The size and number of the grooves 11 can be appropriately adjusted according to the required rigidity. In addition, in the innermost land portion 3d when mounted on a vehicle, a plurality of widthwise sipes 13 are formed which extend inward in the tire width direction from the circumferential main groove 2c and terminate within the innermost land portion 3d when mounted on a vehicle, and a plurality of circumferential sipes 12 which extend from the ends of the widthwise sipes 13 to one side in the tire circumferential direction and terminate within the innermost land portion 3d when mounted on a vehicle. The effects of the pneumatic tire of the present embodiment will be described below.

[0034] According to the pneumatic tire of the present embodiment, first, in the outer central land portion 3b defined between the first circumferential main groove 2a and the second circumferential main groove 2b, a plurality of resonators 4 are provided, including a sub-groove 4a terminating in the outer central land portion 3b and branch grooves 4b, 4c connecting the sub-groove 4a with the first and second circumferential main grooves 2a, 2b. This makes it possible to reduce the air column resonance sound generated in the first and second circumferential main grooves 2a, 2b. Furthermore, in the pneumatic tire of this embodiment, the extension length of the first branch groove 4b and the extension length of the second branch groove 4c are each longer than the length of the sub groove 4a in the tire circumferential direction, so that the groove area of ​​the sub groove 4a is relatively small, and the decrease in the ground contact area when new can be suppressed. As a result, even when the groove depth remains deep from the time of new use to the intermediate stage of wear, the rigidity of the outer central land portion 3b (where the resonator 4 having the widened portion 4d is disposed) can be secured, and the maneuverability performance such as the steering stability can be improved. As described above, according to the pneumatic tire of the present embodiment, it is possible to reduce air column resonance noise while suppressing a decrease in the contact area when the tire is new. Furthermore, in the pneumatic tire of this embodiment, in at least a part of the extension direction of the sub groove 4a and at least a part of the groove depth direction of the sub groove 4a, a widened portion 4d is formed whose groove width is larger than the groove width at the opening to the tread surface 1. This can improve drainage when wear progresses.

[0035] As in this embodiment, the resonator 4 is preferably provided on the outer land portion when mounted on the vehicle. This is because it is possible to increase the rigidity of the outer land portion when mounted on the vehicle (when new), which has a large contribution to driving performance such as steering stability.

[0036] Here, it is preferable that the tire has only three circumferential main grooves 2a to 2c, the first circumferential main groove 2a is located on the outer side when mounted on the vehicle, the second circumferential main groove 2b and the third circumferential main groove 2c adjacent to the outer side in the tire width direction of the second circumferential main groove 2b are located on the inner side when mounted on the vehicle, and the resonator 4 is located on the outer side when mounted on the vehicle, adjacent to the inner side in the tire width direction of the outermost land portion when mounted on the vehicle defined by the tread edge TE and the first circumferential main groove 2a, and is provided in the outer central land portion 3b defined between the first circumferential main groove 2a and the second circumferential main groove 2b. First, since there are only three circumferential main grooves 2, the rigidity of the land portion 3 can be secured more than when four or more circumferential main grooves 2 having the same groove width are provided. In addition, since it is preferable that the outermost land portion 3a when mounted on the vehicle has a particularly high rigidity, it is preferable to increase the rigidity of the land portion without providing a resonator.

[0037] It is also preferable that at least one of the land portions on the inner side when mounted on a vehicle further includes an inner resonator 9 including an inner sub-groove 9a terminating within the land portion and only one inner branch groove 9b connecting the inner sub-groove 9a and the circumferential main groove (the third circumferential main groove 2c in this example), because this can reduce the air column resonance sound generated in the circumferential main groove (the third circumferential main groove 2c in this example).

[0038] Hereinafter, a case where a communication device is provided in a tire will be described. FIG. 6 is a diagram for explaining an example of the arrangement of the communication device. As shown in FIG. 6, the tire may be provided with an RF tag as a communication device 91. The RF tag includes an IC chip and an antenna. The RF tag may be arranged, for example, sandwiched between a plurality of members of the same or different types that constitute the tire. In this way, the RF tag can be easily attached during tire production, and the productivity of tires equipped with the RF tag can be improved. In this example, the RF tag may be arranged, for example, sandwiched between a bead filler and another member adjacent to the bead filler. The RF tag may be embedded in any of the members that constitute the tire. In this way, the load applied to the RF tag can be reduced compared to the case where the RF tag is arranged by being sandwiched between a plurality of members that constitute the tire. This can improve the durability of the RF tag. In this example, the RF tag may be embedded in a rubber member such as a tread rubber or a side rubber. It is preferable that the RF tag is not arranged at a position that is a boundary between members having different rigidities in the periphery length direction, which is a direction along the tire outer surface in a cross-sectional view in the tire width direction. In this way, the RF tag is not placed in a position where distortion is likely to concentrate due to a rigidity step. Therefore, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. In this example, it is preferable that the RF tag is not placed in a position that is a boundary between the end of the carcass and a member adjacent to the end of the carcass (e.g., a side rubber, etc.) in a cross-sectional view in the tire width direction. The number of RF tags is not particularly limited. A tire may include only one RF tag, or may include two or more RF tags. Here, an RF tag is illustrated as an example of a communication device, but a communication device different from the RF tag may be used.

[0039] The RF tag may be disposed, for example, in the tread portion of the tire. In this way, the RF tag is not damaged by a side cut of the tire. The RF tag may be disposed, for example, in the tread center portion in the tire width direction. The tread center portion is a position where deflection is unlikely to concentrate in the tread portion. In this way, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. In addition, it is possible to suppress the occurrence of a difference in communication with the RF tag from both outer sides of the tire in the tire width direction. In this example, the RF tag may be disposed, for example, within a range of 1 / 2 of the tread width with the tire equatorial plane as the center in the tire width direction. The RF tag may be disposed, for example, at the tread end in the tire width direction. When the position of the reader that communicates with the RF tag is predetermined, the RF tag may be disposed, for example, at the tread end on one side closer to the reader. In this example, the RF tag may be disposed, for example, within a range of 1 / 4 of the tread width with the tread end as the outer end in the tire width direction.

[0040] The RF tag may be disposed, for example, on the tire cavity side of a carcass including one or more carcass plies that spans between bead portions. In this way, the RF tag is less likely to be damaged by impacts applied from the outside of the tire, or damage such as side cuts and nail penetration. As an example, the RF tag may be disposed in close contact with the surface of the carcass on the tire cavity side. As another example, when there is another member on the tire cavity side of the carcass, the RF tag may be disposed, for example, between the carcass and another member located on the tire cavity side of the carcass. An example of another member located on the tire cavity side of the carcass is an inner liner that forms the tire inner surface. As another example, the RF tag may be attached to the tire inner surface facing the tire cavity. By configuring the RF tag to be attached to the tire inner surface, it is easy to attach the RF tag to the tire and to inspect and replace the RF tag. In other words, the attachability and maintainability of the RF tag can be improved. In addition, by attaching the RF tag to the inner surface of the tire, it is possible to prevent the RF tag from becoming the core of tire failure, compared to a configuration in which the RF tag is embedded in the tire. Furthermore, when the carcass has multiple carcass plies and there is a position where multiple carcass plies are overlapped, the RF tag may be disposed between the overlapped carcass plies.

[0041] The RF tag may be disposed, for example, in the tread portion of the tire, on the outer side in the tire radial direction of the belt including one or more belt plies. As an example, the RF tag may be disposed on the outer side in the tire radial direction of the belt and in close contact with the belt. In addition, as another example, in the case where a reinforcing belt layer is provided, the RF tag may be disposed on the outer side in the tire radial direction of the reinforcing belt layer and in close contact with the reinforcing belt layer. In addition, as another example, the RF tag may be embedded in the tread rubber on the outer side in the tire radial direction of the belt. By disposing the RF tag on the outer side in the tire radial direction of the belt in the tread portion of the tire, communication with the RF tag from the outside of the tire in the tire radial direction is unlikely to be hindered by the belt. Therefore, it is possible to improve the communication with the RF tag from the outside of the tire in the tire radial direction. In addition, the RF tag may be disposed, for example, in the tread portion of the tire, on the inner side in the tire radial direction of the belt. In this way, the outer side in the tire radial direction of the RF tag is covered by the belt, so that the RF tag is unlikely to be damaged by impact from the tread surface or nail penetration. As one example, the RF tag may be disposed in the tread portion of the tire between the belt and the carcass located radially inward of the belt. In addition, if the belt has a plurality of belt plies, the RF tag may be disposed in the tread portion of the tire between any two belt plies. In this manner, the outer side of the RF tag in the radial direction of the tire is covered by one or more belt plies, so that the RF tag is less susceptible to damage from impacts from the tread surface, nail penetration, and the like.

[0042] The RF tag may be disposed, for example, at a sidewall or bead of the tire. The RF tag may be disposed, for example, at one sidewall or one bead that is closer to a reader that can communicate with the RF tag. In this way, the communication between the RF tag and the reader can be improved. As an example, the RF tag may be disposed between the carcass and the side rubber, or between the tread rubber and the side rubber. The RF tag may be disposed, for example, between the position where the tire is at its maximum width and the position of the tread surface in the tire radial direction. In this way, the communication with the RF tag from the outside of the tire in the tire radial direction can be improved compared to a configuration in which the RF tag is disposed on the inner side in the tire radial direction from the position where the tire is at its maximum width. The RF tag may be disposed, for example, on the inner side in the tire radial direction from the position where the tire is at its maximum width. In this way, the RF tag is disposed near the bead portion that has high rigidity. Therefore, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. As an example, the RF tag may be disposed at a position adjacent to the bead core in the tire radial direction or the tire width direction. Distortion is less likely to concentrate near the bead core. Therefore, the load applied to the RF tag can be reduced. This improves the durability of the RF tag. In particular, it is preferable that the RF tag is disposed in a position radially inward of the maximum tire width position and radially outward of the bead core of the bead portion. In this manner, the durability of the RF tag can be improved, and communication between the RF tag and a reader is less likely to be hindered by the bead core, improving the communication performance of the RF tag. In addition, when the side rubber is composed of multiple rubber members of the same or different types adjacent to each other in the tire radial direction, the RF tag may be disposed by being sandwiched between the multiple rubber members constituting the side rubber.

[0043] The RF tag may be disposed by being sandwiched between the bead filler and a member adjacent to the bead filler. In this way, the RF tag can be disposed in a position where distortion is less likely to be concentrated due to the placement of the bead filler. This reduces the load applied to the RF tag. This improves the durability of the RF tag. The RF tag may be disposed, for example, sandwiched between the bead filler and the carcass. The portion of the carcass that sandwiches the RF tag together with the bead filler may be located on the outer side of the bead filler in the tire width direction, or may be located on the inner side of the tire width direction. When the portion of the carcass that sandwiches the RF tag together with the bead filler is located on the outer side of the bead filler in the tire width direction, the load applied to the RF tag due to impact or damage from the outside of the tire in the tire width direction can be further reduced. This can further improve the durability of the RF tag. Furthermore, the bead filler may have a portion disposed adjacent to the side rubber. In such a case, the RF tag may be disposed sandwiched between the bead filler and the side rubber. Furthermore, the bead filler may have a portion disposed adjacent to the rubber chafer. In such a case, the RF tag may be disposed sandwiched between the bead filler and the rubber chafer.

[0044] The RF tag may be disposed, for example, sandwiched between the rubber chafer and the side rubber. In this way, the RF tag can be disposed at a position where distortion is less likely to be concentrated due to the placement of the rubber chafer. Therefore, the load applied to the RF tag can be reduced. This allows the durability of the RF tag to be improved. The RF tag may be disposed, for example, sandwiched between the rubber chafer and the carcass. In this way, the load applied to the RF tag due to impact or damage from the rim can be reduced. This allows the durability of the RF tag to be improved.

[0045] The RF tag may be sandwiched between the wire chafer and another member adjacent to the wire chafer on the inner or outer side in the tire width direction. In this way, the position of the RF tag is less likely to fluctuate when the tire is deformed. Therefore, the load applied to the RF tag when the tire is deformed can be reduced. This can improve the durability of the RF tag. The other member adjacent to the wire chafer on the inner or outer side in the tire width direction may be, for example, a rubber member such as a rubber chafer. Also, the other member adjacent to the wire chafer on the inner or outer side in the tire width direction may be, for example, a carcass.

[0046] A belt reinforcing layer may be further provided on the radially outer side of the belt. For example, the belt reinforcing layer may be formed by winding a cord made of polyethylene terephthalate continuously in a spiral shape in the tire circumferential direction. Here, the cord may be 6.9×10 -2 The belt reinforcement layer may be formed by applying an adhesive treatment under a tension of 29.4 N / tex or more, and may have an elastic modulus of 2.5 mN / dtex·% or more when a load of 29.4 N is applied, as measured at 160°C. Furthermore, the belt reinforcement layer may be disposed so as to cover the entire belt, or may be disposed so as to cover only both ends of the belt. Furthermore, the winding density per unit width of the belt reinforcement layer may vary depending on the position in the width direction. In this way, road noise and flat spots can be reduced without reducing high-speed durability. [Explanation of symbols]

[0047] 1: Tread surface, 2: circumferential main groove; 2a: first circumferential main groove; 2b: second circumferential main groove; 2c: third circumferential main groove; 3: Rikube, 3a: Outermost land area when installed on vehicle, 3b: Outer center land area, 3c: inner central land area, 3d: innermost land area when installed on vehicle, 4: Resonator, 4a: minor groove, 4b: first branch groove, 4b1: first circumferential portion; 4b2: first widthwise portion; 4c: second branch groove, 4c1: second circumferential portion; 4c2: second widthwise portion; 4d: widened part, 4e: constant groove width part, 4f: groove bottom, 4g: Groove bottom, 4h: Constant groove width part, 4i: Widened part, 4j: Groove bottom, 5: Width direction sipes, 6: Width direction sipes, 7: Width direction sipes, 8: Width direction sipes, 9: Inner resonator, 9a: Inner minor groove, 9b: Inner branch groove, 10: Width sipes, 11: groove portion; 12: circumferential sipe; 13: widthwise sipe; CL: tire equatorial plane, TE: tread edge, 91:Communication equipment

Claims

1. A pneumatic tire having a plurality of circumferential main grooves extending in a tire circumferential direction on a tread surface, A plurality of land portions are defined between a tread edge and the circumferential main groove or between the circumferential main grooves, A land portion partitioned between a first circumferential main groove and a second circumferential main groove adjacent to the first circumferential main groove in the tire width direction is provided with a plurality of resonators, the resonators including a sub-groove terminating within the land portion and a branch groove connecting the sub-groove and the circumferential main groove, the branch groove has a first branch groove connecting an end of the sub groove on one side in the tire circumferential direction to the first circumferential main groove, and a second branch groove connecting an end of the sub groove on the other side in the tire circumferential direction to the second circumferential main groove, the first branch groove has a first circumferential portion extending from an end of the sub groove on one side in the tire circumferential direction to one side in the tire circumferential direction, and a first widthwise portion extending from an end of the first circumferential portion on one side in the tire circumferential direction to communicate with the first circumferential main groove, the second branch groove has a second circumferential portion extending from an end of the sub groove on the other side in the tire circumferential direction to the other side in the tire circumferential direction, and a second widthwise portion extending in the tire width direction from the end of the second circumferential portion on the other side in the tire circumferential direction to communicate with the second circumferential main groove, A widened portion having a groove width larger than the groove width at an opening portion to the tread surface is formed in at least a part of the extension direction of the sub-groove and at least a part of the groove depth direction of the sub-groove, A pneumatic tire, characterized in that an extension length of the first branch groove and an extension length of the second branch groove are each longer than a length of the sub groove in a tire circumferential direction.

2. The pneumatic tire according to claim 1 , wherein the resonator is provided on an outer side of the land portion when the tire is mounted on a vehicle.

3. having only three of the circumferential main grooves, The first circumferential main groove is located on an outer side when mounted on a vehicle, and the second circumferential main groove and a third circumferential main groove adjacent to the outer side of the second circumferential main groove in the tire width direction are located on an inner side when mounted on a vehicle, 3. The pneumatic tire according to claim 2, wherein the resonator is provided in an outer central land portion that is located on the outer side when mounted on a vehicle, adjacent to an outermost land portion when mounted on a vehicle, which is defined by a tread edge and the first circumferential main groove, on the inner side in the tire width direction, and is defined between the first circumferential main groove and the second circumferential main groove.

4. 4. The pneumatic tire according to claim 2, further comprising an inner resonator provided in at least one of the land portions on an inner side when mounted on a vehicle, the inner resonator including an inner sub-groove terminating within the land portion and only one inner branch groove connecting the inner sub-groove and the circumferential main groove.

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