JP2012183885A - Tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire capable of improving uneven wear resistance without lowering wet performance even when mounted on a steering wheel of a heavy load vehicle such as a truck and a bus.SOLUTION: In a pneumatic tire, a length L1 in a tread width direction of a center land part 100 varies with circumferential advancement in a tire; a width direction end 105 in the tread of the center land part 100 has a projected portion 105a to be in a projected state width direction in the tread and a depressed part 105b to be in a depressed state; a sipe extends the width direction in the tread, crosses the center land part 100, and includes a sipe 110 communicating with a circumferential groove in the projected portion 105a; a wide groove extends the width direction in the tread and includes a wide groove 120 communicating with a circumferential groove in the depressed part 105b; and no radial groove depressed inside in a tire is formed in a shoulder land part 300A.

Description

  The present invention relates to a tire provided with a rib-like land portion defined by a plurality of circumferential grooves extending in the tire circumferential direction and taking into account uneven wear resistance and wet performance.

  Conventionally, tires mounted on heavy-duty vehicles such as trucks and buses are more heavily loaded than conventional tires mounted on passenger cars, etc., taking into account traveling patterns unique to trucks and buses, and suppressing uneven wear. Various tread patterns that take into account are adopted. For example, a rib-like land portion defined by a plurality of circumferential grooves extending in the tire circumferential direction is provided, a wide groove crossing the rib-like land portion, and a sipe extending inward in the tire radial direction from the groove bottom of the wide groove A tire in which is formed is known (for example, Patent Document 1).

  According to such a tire, only a wide groove is exposed on the tread until it travels a certain distance from the start of use of the tire, and a sipe having a groove width narrower than that of the wide groove is not exposed on the tread. The portion that can become the core of uneven wear is reduced, and uneven wear can be effectively suppressed. Further, since the drainage is improved by a plurality of circumferential grooves and wide grooves, so-called wet performance such as braking performance on a wet road surface can be secured.

JP 2000-168317 A (pages 3-4, FIGS. 5, 7)

  By the way, in the case of a tire mounted on a steered wheel (steering wheel), a greater lateral force is input as compared to a tire mounted on a non-steered wheel. For this reason, even if the tire is designed to suppress uneven wear as described above, the occurrence of uneven wear cannot be reliably suppressed, and there is room for further improvement. In particular, when the above-described conventional tire is mounted on a wheel to be steered, there is a problem that heel and toe wear centering on the end of the wide groove of the rib-like land portion provided near the tread shoulder tends to occur. It was.

  Of course, in order to suppress such uneven wear, wide grooves and sipes may be removed, but this causes another problem that wet performance is degraded.

  Therefore, the present invention has been made in view of such a situation, and even when it is mounted on a steering wheel of a heavy-duty vehicle such as a truck or a bus, the uneven wear resistance is reduced without reducing the wet performance. The object is to provide an improved tire.

  In order to solve the above-described problems, the present invention has the following features. A feature of the present invention is that a rib-like land portion (for example, the center land portion 100) defined by a plurality of circumferential grooves (for example, the center circumferential direction groove 20A) extending in the tire circumferential direction (DR2 direction) is provided and grounded. A sipe having a groove width formed to close occasionally (for example, sipe 110) and a wide groove (for example, wide groove 120) having a groove depth shallower than that of the sipe and having a wider groove width (for example, wide groove 120). The rib-shaped land portion is formed in the center region (center region A1) including the tire equator line (tire equator line CL) (for example, the pneumatic tire 10). , A center land portion 100) and a shoulder land portion (for example, shoulder land portion 300A) provided on the outermost side in the tread width direction (DR1 direction). The length in the width direction (length L1) changes as it proceeds in the tire circumferential direction, and the end portion (for example, the end portion 105) of the center land portion in the tread width direction is convex in the tread width direction. And a sipe extending in the tread width direction, crossing the center land portion, and in the convex portion. A center sipe (sipe 110) that communicates with the circumferential groove, and the wide groove includes a center wide groove (wide groove 120) that extends in the tread width direction and communicates with the circumferential groove in the concave portion. The gist of the invention is that the shoulder land portion is not formed with a groove recessed inward in the tire radial direction.

  In addition, the groove | channel recessed in a tire radial inside means the groove | channel intentionally formed in manufacture, and the thing (for example, damage | wound by damage) recessed in the tire radial inside produced at the time of manufacture or during use is not included.

  Further, the convex portions and the concave portions are alternately arranged in the tire circumferential direction, so that the end portion in the tread width direction of the center land portion has an amplitude along the tread width direction. (For example, amplitude S1A), and the center sipe and the center wide groove may be alternately formed in the tire circumferential direction.

  The rib-shaped land portion includes a second land portion (for example, the second land portion 200A) adjacent to the center land portion on the outer side in the tread width direction with the circumferential groove interposed therebetween, and the tread of the second land portion is included. The outer end in the width direction may be linear along the tire circumferential direction.

  Further, the length of the second land portion in the tread width direction (for example, L2A) changes as it proceeds in the tire circumferential direction, and an end portion (end portion 205A) of the second land portion on the inner side in the tread width direction is changed. In the tread width direction, the sipe has a convex portion (convex end portion 205a) and a concave portion (concave end portion 205b), and the sipe extends in the tread width direction. The portion that is convex toward the inside in the tread width direction includes a second sipe (sipe 210) that communicates with the circumferential groove, and the wide groove extends in the tread width direction, and the tread of the second land portion. A portion that is concave outward in the width direction includes a second wide groove (wide groove 220) that communicates with the circumferential groove, and the second sipe is the tread of the second land portion. Communicated with a circumferential groove located on the outer side in the direction, crossing the second land portion, and an end portion of the second wide groove on the outer side in the tread width direction is located inside the second land portion, The length in the tread width direction may be 80% or less of the minimum width in the tread width direction of the second land portion.

  Further, the center wide groove crosses the center land portion, and in the tire circumferential direction, the position of the inner end of the second sipe in the tread width direction is adjacent to the center wide groove across the circumferential groove. You may overlap with the position of the edge part of the tread width direction outside of a slot.

Further, in the tire circumferential direction, the position of the inner end of the second wide groove in the tread width direction overlaps with the position of the outer end of the center sipe adjacent in the tread width direction across the circumferential groove. The groove width of the sipe is 1.5 mm or less, the groove width of the wide groove is 2.0 mm or more, and the groove depth of the wide groove is equal to the groove depth of the circumferential groove. It may be 15% or less.

The length of the shoulder land portion in the tread width direction is 1.25 times or more and 1.50 times or less of the maximum width of the center land portion in the tread width direction. The length in the tread width direction may be 1.10 times or more and 1.20 times or less with respect to a specified rim width of a normal rim on which the tire is mounted.

  The “regular rim” refers to a standard rim in an applicable size defined in the Year Book 2008 edition of JATMA (Japan Automobile Tire Association). Outside Japan, this refers to the standard rim at the applicable size described in the standards described below. The standards are determined by industry standards that are valid in the region where the tire is produced or used. For example, in the United States, it is “The Year Book of The Tire and Rim Association Inc.”, and in Europe it is “The Standards Manual of the European Tire and Rim Technical Organization”.

  Note that “grounding” is grounding at a specified internal pressure and a specified load.

  According to the features of the present invention, it is possible to provide a tire with improved wear resistance without deteriorating wet performance even when mounted on the steering wheel of a heavy load vehicle such as a truck or bus.

FIG. 1 is a cross-sectional view of the pneumatic tire 10 according to the first embodiment of the present invention along the tread width direction and the tire radial direction. FIG. 2 is a developed tread plan view of the pneumatic tire 10 according to the first embodiment of the present invention. Drawing 3 is a tread plane development view and sectional view of pneumatic tire 10 concerning a 1st embodiment of the present invention. FIG. 4 is a developed plan view of a tread of a pneumatic tire according to an embodiment of the present invention. FIG. 5 is a developed tread plan view of a pneumatic tire according to a comparative example of the present invention. FIG. 6 is a tread plane development view of the pneumatic tire 11 according to the second embodiment of the present invention.

  Next, an embodiment of a tire according to the present invention will be described with reference to the drawings. Specifically, the first embodiment, the second embodiment, and other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

[First Embodiment]
1st Embodiment demonstrates (1) schematic structure of a tire, (2) the shape of a sipe and a wide groove, (3) comparison and evaluation, and (4) effect | action and effect.

(1) Schematic Configuration of Tire FIG. 1 is a cross-sectional view of the pneumatic tire 10 according to the first embodiment of the present invention along the tread width direction and the tire radial direction. FIG. 2 is a developed tread plan view of the pneumatic tire 10 according to the first embodiment. The pneumatic tire 10 is a pneumatic tire that is assumed to be mounted on a steering wheel of a heavy-duty vehicle such as a truck or a bus. However, the mountable position of the pneumatic tire 10 is not limited to the steered wheels. The pneumatic tire 10 may be filled with an inert gas such as nitrogen gas.

  As shown in FIG. 1, the pneumatic tire 10 includes a pair of bead cores 40 and a carcass 60 disposed so as to straddle between the pair of bead portions. The pneumatic tire 10 may include a belt layer that is positioned on the inner side in the tire radial direction (DR3 direction in the drawing) of the tread surface TR that contacts the ground and extends in the tire circumferential direction.

  As shown in FIG. 2, the pneumatic tire 10 is formed with a plurality of circumferential grooves extending in the tire circumferential direction (DR2 direction in the drawing). Specifically, center circumferential grooves 20A and 20B and outer circumferential grooves 30A and 30B are formed.

  The pneumatic tire 10 is provided with a plurality of rib-like land portions defined by these circumferential grooves. Specifically, in the present embodiment, the rib-shaped land portion includes a center land portion 100, second land portions 200A and 200B, and shoulder land portions 300A and 300B.

  As shown in FIG. 2, the center land portion 100 defined by the center circumferential groove 20A and the center circumferential groove 20B is provided in the center region A1 including the tire equator line CL. The center land portion 100 extends in the tire circumferential direction. The center region A1 includes the tire equator line CL, and when the land portion of the tread of the pneumatic tire 10 is divided by a plurality of circumferential grooves, the tread width direction of the rib-like land portion closest to the tire equator line This corresponds to the length L1 in the (DR1 direction in the figure). Therefore, in the present invention, one or two center land portions are provided in the center region A1. In the present embodiment, there is one center land portion (that is, the center land portion 100), and in the second embodiment described later, there are two center land portions (that is, the center land portions 150A and 150B). .

  The length L1 of the center land portion 100 in the tread width direction changes as it proceeds in the tire circumferential direction. The end portion 105 in the tread width direction of the center land portion 100 includes a convex end portion 105a that is a convex portion in the tread width direction and a concave end portion 105b that is a concave portion in the tread width direction. The convex end portions 105a and the concave end portions 105b are alternately arranged in the tire circumferential direction. The end portion 105 in the tread width direction of the center land portion 100 has amplitudes S1A and S1B along the tread width direction.

  In the present embodiment, the periods of the amplitudes S1A and S1B of the both end portions 105 of the center land portion 100 in the tread width direction are shifted from each other. Therefore, both end portions 105 of the center land portion 100 in the tread width direction are asymmetric with the tire equator line CL as an axis.

  As shown in FIG. 2, closer to the tread shoulder TS than the center land portion 100, the second land portion 200A partitioned by the center circumferential groove 20A and the outer circumferential groove 30A, and the center circumferential groove 20B and the outside A second land portion 200B partitioned by the circumferential groove 30B is provided. The second land portion 200A (second land portion 200B) is adjacent to the center land portion 100 on the outer side in the tread width direction with the center circumferential groove 20A (center circumferential groove 20B) interposed therebetween. That is, the second land portion 200A (second land portion 200B) is adjacent to the center land portion 100 via the center circumferential groove 20A (center circumferential groove 20B).

  The length L2A (length L2B) in the tread width direction of the second land portion 200A (second land portion 200B) changes as it proceeds in the tire circumferential direction. The end portion 205A on the inner side in the tread width direction of the second land portion 200A (second land portion 200B) is a convex end portion 205a that is a convex portion toward the inner side in the tread width direction, and a concave portion on the outer side in the tread width direction. And a concave end portion 205b. The end portion 205A on the inner side in the tread width direction of the second land portion 200A (second land portion 200B) has a concave shape on the outer side in the tread width direction. The center circumferential groove 20A (center circumferential groove 20B) protrudes on the outer side in the tread width direction. It means to become a shape. The convex end portions 205a and the concave end portions 205b are alternately arranged in the tire circumferential direction. Accordingly, the end portion 205 on the inner side in the tread width direction of the second land portion 200A (second land portion 200B) has an amplitude S2A (amplitude S2B) in the tread width direction. An end 205B on the outer side in the tread width direction of the second land portion 200A (second land portion 200B) is linear along the tire circumferential direction.

  As shown in FIG. 2, the shoulder land portion 300A (shoulder land portion 300B) is provided on the outermost side in the tread width direction in the rib-like land portion. The shoulder land portion 300A (shoulder land portion 300B) is provided on the tread shoulder TS side of the center circumferential groove 20A (center circumferential groove 20B) and extends in the tire circumferential direction.

  The shoulder land portion 300A (shoulder land portion 300B) is not formed with a groove recessed inward in the tire radial direction. Therefore, there is no unevenness on the surface in the tire radial direction (ground contact surface) of the shoulder land portion 300A (shoulder land portion 300B). In other words, sipes and wide grooves are formed only in the center land portion 100 and the second land portion 200A (second land portion 200B).

  The center circumferential groove 20A (center circumferential groove 20B) is formed between the center land portion 100 and the second land portion 200A (second land portion 200B). The center circumferential groove 20A (center circumferential groove 20B) corresponds to the end portion 105 of the center land portion 100 and the end portion 205A of the second land portion 200A (second land portion 200B). It is not linear like the circumferential groove 30B, but is non-linear, specifically zigzag.

  More precisely, the center circumferential groove 20A and the center circumferential groove 20B have a predetermined amplitude along the tread width direction. That is, the center circumferential groove 20A and the center circumferential groove 20B extend along the tire circumferential direction while meandering in the tread width direction, and the amplitude along the tread width direction is repeated every predetermined distance in the tire circumferential direction. It is. Specifically, the predetermined amplitude is preferably 0.05 to 0.3 times the length L2A (L2B) in the tread width direction of the second land portion 200A (second land portion 200B).

  The outer circumferential groove 30A (outer circumferential groove 30B) is the tread shoulder TS side of the center circumferential groove 20A (center circumferential groove 20B), specifically, the tread shoulder of the second land portion 200A (second land portion 200B). It is formed on the TS side.

  The outer circumferential groove 30A (outer circumferential groove 30B) is formed between the second land portion 200A (second land portion 200B) and the shoulder land portion 300A (shoulder land portion 300B). The outer circumferential groove 30A and the outer circumferential groove 30B are linear along the tire circumferential direction. Further, the groove width W1 of the center circumferential groove 20A (center circumferential groove 20B) is narrower than the groove width W2 of the outer circumferential groove 30A (outer circumferential groove 30B).

  Sipes and wide grooves are formed in the center land portion 100 and the second land portion 200A (second land portion 200B). A sipe is a sipe having a groove width formed so as to close when grounded. The wide groove is a wide groove having a groove depth shallower than that of the sipe and a wider groove width. The groove width of the sipe is preferably 1.5 mm or less. The groove width of the wide groove is preferably 2.0 mm or more. The groove depth of the wide groove is preferably 15% or less of the groove depth of the center circumferential groove 20A. In addition, in FIG. 2, the illustration by the code | symbol of the sipe and wide groove formed in the 2nd land part 200B is abbreviate | omitted.

  Specifically, a plurality of sipes 110 and wide grooves 120 are formed in the center land portion 100. The sipe 110 and the wide groove 120 extend in the tread width direction. The groove width W4 of the wide groove 120 is wider than the groove width W3 of the sipe 110 and narrower than the center circumferential groove 20A (and the center circumferential groove 20B). The wide groove 120 is formed between two sipes 110 adjacent to each other. That is, sipes 110 and wide grooves 120 are alternately formed in the tire circumferential direction.

  A plurality of sipes 210 and wide grooves 220 are formed in the second land portion 200A (second land portion 200B). The sipe 210 and the wide groove 220 extend in the tread width direction. The groove width W4 of the wide groove 220 is wider than the groove width W3 of the sipe 210 and narrower than the center circumferential groove 20A (and the center circumferential groove 20B). The wide groove 220 is formed between two sipes 210 adjacent to each other. That is, the sipe 210 and the wide groove 220 are alternately formed in the tire circumferential direction.

  The sipe 110 and the wide groove 120 formed in the center land portion 100 are non-linear having an amplitude S3 (predetermined amplitude) along the tire circumferential direction. That is, the sipe 110 and the wide groove 120 extend along the tread width direction while meandering in the tire circumferential direction. On the other hand, the sipe 210 and the wide groove 220 formed in the second land portion 200A (second land portion 200B) are not meandering like the sipe 110 and the wide groove 120, and are slightly curved, but along the tread width direction. Extend substantially linearly.

  Further, both ends of the wide groove 120 communicate with the center circumferential groove 20A and the center circumferential groove 20B, respectively, but the wide groove 220 communicates with the center circumferential groove 20A only at the end on the tire equator line CL side. is doing.

  The length L3A (length L3B) of the shoulder land portion 300A (shoulder land portion 300B) in the tread width direction is 1.25 times or more and 1.50 times the maximum width in the length L1 of the center land portion 100 in the tread width direction. The following is preferable. Further, the length TW in the tread width direction of the tread surface TR that is the ground contact surface is 1.10 times or more and 1.20 times or less than the specified rim width RW of the regular rim 80 to which the pneumatic tire 10 is attached. Preferably there is.

(2) Shapes of sipe and wide groove Next, shapes of sipe and wide groove formed in the center land portion 100 and the second land portion 200A (second land portion 200B) will be described with reference to FIGS. ) Will be described in detail.

  FIG. 3A is a developed plan view of the tread of the pneumatic tire 10 and shows a part of FIG. FIG.3 (b) is sectional drawing of the pneumatic tire 10 along the F2B-F2B line | wire shown to Fig.3 (a). FIG.3 (c) is sectional drawing of the pneumatic tire 10 along the F2C-F2C line | wire shown to Fig.3 (a). Hereinafter, the sipe and the wide groove formed in the second land portion 200B are the same as the sipe and the wide groove formed in the second land portion 200A, and thus description thereof is omitted.

(2.1) Center land 100
As shown in FIGS. 2 and 3A to 3C, a sipe 110 and a wide groove 120 are formed in the center land portion 100. The sipe 110 crosses the center land portion 100. That is, the sipe 110 communicates with the center circumferential groove 20A and the center circumferential groove 20B. In the present embodiment, the wide groove 120 also crosses the center land portion 100. The wide groove 120 communicates with the center circumferential groove 20A and the center circumferential groove 20B. In the present embodiment, the sipes 110 and the wide grooves 120 are alternately formed at equal intervals.

  The sipe 110 communicates with the center circumferential groove 20A and the center circumferential groove 20B at the convex end portion 105a. That is, the sipe 110 communicates with the center circumferential groove 20A and the center circumferential groove 20B in the wide portion 100a where the center land portion 100 is wide along the tread width direction. Specifically, the sipe 110 includes, in the region between the wide grooves 120 adjacent to each other in the tire circumferential direction, a portion where the side wall on the center circumferential groove 20A side of the center land portion 100 is located on the outermost side in the tread width direction, The side wall of the land portion 100 on the side of the center circumferential groove 20B is formed in a region that linearly connects a portion that is located most outward in the tread width direction. In the present embodiment, the periods of the amplitudes S1A and S1B of both end portions 105 of the center land portion 100 in the tread width direction are shifted from each other, so that the wide portion 100a extends obliquely with respect to the tread width direction.

  The wide groove 120 also communicates with the center circumferential groove 20A and the center circumferential groove 20B at the concave end portion 105b. Other configurations of the wide groove 120 are the same as those of the sipe 110.

(2.2) Second land 200A
As shown in FIGS. 3A to 3C, a sipe 210 and a wide groove 220 are formed in the second land portion 200A. The sipe 210 crosses the second land portion 200B. That is, the sipe 210 communicates with the center circumferential groove 20A and the outer circumferential groove 30A. The sipe 210 communicates with the center circumferential groove 20A at the convex end portion 205a. The wide groove 220 is formed between two sipes 210 adjacent to each other. The end 220a of the wide groove 220 on the center land portion 100 side communicates with the center circumferential groove 20A formed between the center land portion 100 and the second land portion 200A at the concave end portion 205b. On the other hand, the end 220b of the wide groove 220 on the tread shoulder TS side does not communicate with the outer circumferential groove 30A and is terminated in the second land portion 200A. That is, the end 220b of the wide groove 220 on the outer side in the tread width direction is located inside the second land portion 200A. The length L4 in the tread width direction of the wide groove 220 is preferably 80% or less of the minimum width in the tread width direction of the second land portion 200A. In consideration of improvement in drainage performance and wet performance due to an increase in edge components, the length L4 is preferably 50% or more of the minimum width in the tread width direction of the second land portion 200A.

  The groove depth D11 of the sipe 110 and the groove depth D12 of the sipe 210 are deeper than the groove depth D12 of the wide groove 120 and the groove depth D22 of the wide groove 220. In the present embodiment, the groove depth D11 and the groove depth D21 are the same, and the groove depth 12 and the groove depth 22 are the same. The groove depth is a distance from the tread surface TR to the groove bottom. In this embodiment, the center circumferential groove 20A and the outer circumferential groove 30A have the same groove depth (groove depth D1).

  The position of the sipe 210 formed in the second land portion 200A in the tire circumferential direction overlaps the position of the wide groove 120 formed in the center land portion 100 in the tire circumferential direction. That is, in the tire circumferential direction, the position of the end portion 210a on the inner side in the tread width direction of the sipe 210 overlaps with the position of the end portion 120a on the outer side in the tread width direction of the adjacent wide groove 120 across the center circumferential groove 20A. . The position of the wide groove 220 formed in the second land portion 200 </ b> A in the tire circumferential direction overlaps the position of the sipe 110 formed in the center land portion 100 in the tire circumferential direction. That is, in the tire circumferential direction, the position of the end portion 220a on the inner side in the tread width direction of the wide groove 220 overlaps with the position of the end portion 110a on the outer side in the tread width direction of the adjacent sipe 110 across the center circumferential groove 20A. . The sipe 110 and the wide groove 120 have the amplitude S3 (see FIG. 1), but the sipe 210 and the wide groove 220 only need to be positioned within the range of the amplitude S2.

(3) Comparison / Evaluation Next, a comparison test method and the test results of the pneumatic tire 10 described above and the pneumatic tire of the comparative example will be described.

(3.1) Test target tire and test conditions A pneumatic tire having a tread pattern shown in FIG. 4 was used as a tire according to the example. Although it is the same structure as the pneumatic tire 10 mentioned above, the stone biting prevention protrusion for preventing a stone from getting caught in the center circumferential groove 20A and the center circumferential groove 20B is the center circumferential groove 20A and the center circumferential groove 20B. Are provided in plurality. Moreover, the pneumatic tire which has a tread pattern shown in FIG. 5 was used as a tire according to a comparative example. The comparative tests were conducted on (i) turning performance on a wet road surface, (ii) braking performance on a wet road surface, and (iii) wear performance.

  (I) In the test of turning performance on a wet road surface, turning acceleration on a wet Belgian road (cobblestone road) was evaluated. (Ii) In the test of braking performance on a wet road surface, a deceleration index on a wet asphalt road was evaluated. (Iii) In the wear performance test, the travel distance until any of the wide grooves disappeared due to wear on the dry road surface (drum testing machine) was evaluated.

  The test conditions are as follows.

-Vehicle type: Semi-trailer-Tire size: 295 / 80R22.5
・ Rim size used: 8.25 × 22.5
・ Set air pressure: 850kPa
・ Set load: Regular load 3550kg (ETRTO single wheel load)
(3.2) Test result Table 1 shows the result of each test mentioned above. The values shown in Table 1 are obtained by displaying the results of the examples in terms of indexes when the comparative example is 100.

As shown in Table 1, although the wet performance is the same as that of the example and the comparative example, it was confirmed in the wear performance test that the example exceeded the comparative example. Therefore, according to this embodiment, it was confirmed that the wear resistance performance was improved without reducing the wet performance. Wet (4) Action / Effect According to the pneumatic tire 10 described above, the shoulder land portion 300 </ b> A and the shoulder land portion 300 </ b> B are not formed with grooves recessed inward in the tire radial direction. That is, a sipe or a wide groove is not formed in the shoulder land portion 300A (shoulder land portion 300B) as in a conventional pneumatic tire. For this reason, even if a large lateral force is input to the shoulder land portion, heel and toe wear with the sipe and the end of the wide groove as the core does not occur. Further, the sipe 110 communicates with the center circumferential groove 20A and the center circumferential groove 20B at the convex end portion 105a, and the wide groove 120 communicates with the center circumferential groove 20A and the center circumferential groove 20B at the concave end portion 105b. Communicate. Since the sipe 110 is formed so as to be closed when grounded, the deformation of the center land portion 100 is suppressed as compared with the wide groove 120, and the decrease in rigidity of the center land portion 100 is suppressed. For this reason, drainage performance and edge components can be secured and wet performance can be maintained by communicating at the convex end portion 205a while suppressing a decrease in rigidity of the center land portion 100. On the other hand, although the rigidity of the center land portion 100 is lower than that of the sipe 110, the drain end performance is improved more than that of the sipe 110 by minimizing the decrease in rigidity of the center land portion 100 by communicating at the concave end portion 105b. Since the wide groove 120 is formed, wet performance can be maintained. The sipe 110 and the wide groove 120 communicate with the center circumferential groove 20A and the center circumferential groove 20B at different portions. For this reason, even if the groove | channel recessed in a tire radial direction inner side is not formed in the shoulder land part 300A and the shoulder land part 300B, drainage property is securable. That is, according to the pneumatic tire 10, even when it is mounted on the steering wheel of a heavy-duty vehicle such as a truck or a bus, the wear resistance can be improved without reducing the wet performance.

  In the present embodiment, the end portion 105 in the tread width direction of the center land portion 100 has amplitudes S1A and S1B along the tread width direction. Thereby, since the edge component of the center land part 100 increases, wet performance can be maintained thru | or improved. Further, sipes 110 and wide grooves 120 are alternately formed in the tire circumferential direction. For this reason, since the fall of the fall of the rigidity of the center land part 100 and drainage can be ensured with sufficient balance, wet performance can be maintained thru | or improved.

  In the present embodiment, the end portion 205B on the outer side in the tread width direction of the second land portion 200A and the second land portion 200B is linear along the tire circumferential direction. Thereby, the progress of uneven wear due to the lateral force can be effectively suppressed.

  The sipe 210 crosses the second land portion 200B and communicates with the center circumferential groove 20A at the convex end portion 205a. Thereby, drainage performance and edge components can be secured, and wet performance can be maintained. The end 220a of the wide groove 220 on the center land portion 100 side communicates with the center circumferential groove 20A at the concave end portion 205b, and the end 220b of the wide groove 220 on the outer side in the tread width direction is the second land portion 200A. It is located inside (second land portion 200B). By preventing the wide groove 120 from communicating with the second land portion 200A (second land portion 200B), a decrease in rigidity of the second land portion 200B can be suppressed. That is, the shearing force when the second land portion 200 </ b> A is kicked off the road surface with the rotation of the pneumatic tire 10 is reduced. In particular, the shear force in a state where lateral force is input from the outside when the vehicle is mounted is reduced. If the length L4 in the tread width direction of the wide groove 220 is 80% or less of the minimum width in the tread width direction of the second land portion 200A, it is possible to further suppress a decrease in rigidity of the second land portion 200B.

  In the present embodiment, in the tire circumferential direction, the position of the end 210a on the inner side in the tread width direction of the sipe 210 is the same as the position of the end 120a on the outer side in the tread width direction of the adjacent wide groove 120 across the center circumferential groove 20A. overlapping. In the tire circumferential direction, the position of the end portion 220a on the inner side in the tread width direction of the wide groove 220 overlaps the position of the end portion 110a on the outer side in the tread width direction of the adjacent sipe 110 with the center circumferential direction groove 20A interposed therebetween. . For this reason, since the sipe and the wide groove are connected along the tread width direction, drainage performance is improved. Moreover, since the wide groove does not continue in the tread width direction, deformation of the rib-like land portion (center land portion 100, second land portion 200A) during stepping on or kicking out is suppressed.

  In this embodiment, the groove width of the sipe is 1.5 mm or less, the groove width of the wide groove is 2.0 mm or more, and the groove depth of the wide groove is equal to the groove depth of the center circumferential groove 20A. 15% or less. Thereby, while suppressing a deformation | transformation of a rib-shaped land part (center land part 100, 2nd land part 200A), wet performance can be maintained.

  In the present embodiment, the length L3A (length L3B) in the tread width direction of the shoulder land portion 300A (shoulder land portion 300B) is 1.25 times the maximum width in the length L1 of the center land portion 100 in the tread width direction. It is more than 1.50 times. Further, the length TW in the tread width direction of the tread surface TR that is the ground contact surface is 1.10 times or more and 1.20 times or less than the specified rim width RW of the regular rim 80 to which the pneumatic tire 10 is attached. is there. With such a configuration, the wet performance can be maintained or improved and the wear resistance can be improved.

  In the present embodiment, the sipe 110 and the wide groove 120 formed in the center land portion 100 are non-linear having a predetermined amplitude S2 along the tire circumferential direction. For this reason, deformation of the center land portion 100 at the time of stepping on and kicking out is suppressed, and uneven wear of the center land portion 100 can be further effectively suppressed.

[Second Embodiment]
FIG. 6 is a tread plane development view of the pneumatic tire 11 according to the second embodiment. In the following, portions different from the pneumatic tire 10 described above will be mainly described, and descriptions of portions similar to the pneumatic tire 10 will be omitted as appropriate.

  As shown in FIG. 3, in the pneumatic tire 11, two center land portions 150A and a center land portion 150B are provided in the center region A1.

  The length L1A (L2B) in the tread width direction of the center land portion 150A (center land portion 150B) changes as the tire progresses in the tire circumferential direction. The center land portion 150A (center land portion 150B) has an end portion 155A on the inner side in the tread width direction, a convex end portion 155a that is a convex portion in the tread width direction, and a concave end portion that is a concave portion in the tread width direction. 155b. The convex end portions 155a and the concave end portions 155b are alternately arranged in the tire circumferential direction. The end portion 155A on the inner side in the tread width direction of the center land portion 100 has an amplitude along the tread width direction, as in the first embodiment.

  The center land portion 150A (center land portion 150B) tread width direction outer end portion 155B is linear along the tire circumferential direction.

  The configuration of the shoulder land portion 300A (shoulder land portion 300B) is the same as that of the first embodiment. The length L3A (length L3B) in the tread width direction of the shoulder land portion 300A (shoulder land portion 300B) is the maximum width in the length L1A (L1B) in the tread width direction of the center land portion 150A (center land portion 150B). It is preferable that it is 1.25 times or more and 1.50 times or less.

  The center circumferential groove 21 is formed on the equator line CL. The center circumferential groove 21 is formed between the center land portion 150A and the center land portion 150B. The center circumferential groove 21 corresponds to the end portion 155A of the center land portion 150A and the center land portion 150B, and is not linear but non-linear like the outer circumferential groove 30A and the outer circumferential groove 30B. It has a zigzag shape.

  The sipe 160A (sipe 160B) and the wide groove 170A (wide groove 170B) formed in the center land portion 150A (center land portion 150B) have the same configuration as the sipe 210 and wide groove 220 of the first embodiment, respectively.

  The position of the sipe 160A formed in the center land portion 150A in the tire circumferential direction overlaps the position of the wide groove 170B formed in the center land portion 150B in the tire circumferential direction. That is, in the tire circumferential direction, the position of the end of the sipe 160A on the inner side in the tread width direction overlaps the position of the end of the wide groove 170B on the inner side in the tread width direction. Further, the position of the sipe 160B formed in the center land portion 150B in the tire circumferential direction overlaps the position of the wide groove 170A formed in the center land portion 150A in the tire circumferential direction. That is, in the tire circumferential direction, the position of the end of the sipe 160B on the inner side in the tread width direction overlaps the position of the end of the wide groove 170A on the inner side in the tread width direction.

[Other Embodiments]
As described above, the contents of the present invention have been disclosed through the first embodiment and the second embodiment of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, in the first embodiment described above, the sipe 110 and the wide groove 120 are non-linear with a predetermined amplitude S2 along the tire circumferential direction, but the sipe 110 and the wide groove 120 may be linear. I do not care.

  The pneumatic tire 10 and the pneumatic tire 11 are assumed to be mounted on the steering wheel of a heavy-duty vehicle such as a truck or a bus. However, the present invention is mounted on a vehicle other than a heavy-duty vehicle such as a truck or a bus. You may apply to the tire which is done.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 10,11 ... Pneumatic tire, 20A, 20B, 21 ... Center circumferential groove, 30A, 30B ... Outer circumferential groove, 40 ... Bead core, 60 ... Carcass, 80 ... Regular rim, 100, 150A, 150B ... Center land part 100a ... Wide part 105,110a, 120a, 155A, 155B, 205,205A, 205B, 210a, 220a, 220b ... End, 105a, 155a, 205a ... Convex end, 105b, 155b, 205b ... Concave end 110, 160A, 160B, 210 ... sipe, 120, 170A, 170B, 220 ... wide groove, 200A, 200B ... second land part, 300A, 300B ... shoulder land part,

Claims (9)

A sipe having a rib-like land portion defined by a plurality of circumferential grooves extending in the tire circumferential direction, having a groove width formed so as to close when grounded, and having a groove depth shallower than the sipe and having a groove width A wide wide groove is a tire formed in the rib-like land portion,
The rib-like land portion includes a center land portion provided in a center region including the tire equator line, and a shoulder land portion provided on the outermost side in the tread width direction,
The length in the tread width direction of the center land portion changes as it advances in the tire circumferential direction, and the end portion of the center land portion in the tread width direction has a concave portion and a convex portion in the tread width direction. And a portion that becomes
The sipe includes a center sipe that extends in the tread width direction, crosses the center land portion, and communicates with the circumferential groove in the convex portion.
The wide groove includes a center wide groove that extends in the tread width direction and communicates with the circumferential groove in the concave portion.
A tire in which a groove recessed in the tire radial direction is not formed in the shoulder land portion. The convex portions and the concave portions are alternately arranged in the tire circumferential direction, so that the end portion of the center land portion in the tread width direction has an amplitude along the tread width direction. And
The tire according to claim 1, wherein the center sipe and the center wide groove are alternately formed in the tire circumferential direction. The rib-shaped land portion includes a second land portion adjacent to the center land portion on the outer side in the tread width direction with the circumferential groove interposed therebetween,
The tire according to claim 1 or 2, wherein an end of the second land portion on the outer side in the tread width direction is linear along the tire circumferential direction. The length in the tread width direction of the second land portion changes as it proceeds in the tire circumferential direction,
The end of the second land portion on the inner side in the tread width direction has a convex portion and a concave portion in the tread width direction,
The sipe includes a second sipe that extends in the tread width direction and communicates with the circumferential groove in a portion that protrudes inward in the tread width direction of the second land portion.
The wide groove includes a second wide groove that extends in the tread width direction and communicates with the circumferential groove at a portion that is concave outward in the tread width direction of the second land portion.
The second sipe communicates with a circumferential groove located on the outer side in the tread width direction of the second land portion, and crosses the second land portion,
An end of the second wide groove on the outer side in the tread width direction is located inside the second land portion,
The tire according to claim 3, wherein a length of the second wide groove in the tread width direction is 80% or less of a minimum width of the second land portion in the tread width direction. The center wide groove crosses the center land portion,
In the tire circumferential direction, the position of the end portion of the second sipe on the inner side in the tread width direction overlaps with the position of the end portion on the outer side in the tread width direction of the center wide groove adjacent to the circumferential groove. Item 5. The tire according to Item 4.   In the tire circumferential direction, the position of the inner end of the second wide groove in the tread width direction overlaps with the position of the outer end of the center sipe adjacent in the tread width direction across the circumferential groove. Item 6. The tire according to Item 4 or 5. The groove width of the sipe is 1.5 mm or less,
The groove width of the wide groove is 2.0 mm or more,
The tire according to any one of claims 1 to 6, wherein a groove depth of the wide groove is 15% or less of a groove depth of the circumferential groove.   The length in the tread width direction of the shoulder land portion is not less than 1.25 times and not more than 1.50 times the maximum width in the tread width direction of the center land portion. The described tire.   The length in the tread width direction of the tread surface which is a contact surface is 1.10 times or more and 1.20 times or less with respect to a specified rim width of a normal rim on which the tire is mounted. The tire according to any one of claims.

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