JP2011057064A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire more surely suppressing deterioration of wear resistance while ensuring driving performance, when the length of a block along a tire circumferential direction is formed longer than the width of a lateral groove along the tire circumferential direction. <P>SOLUTION: In the pneumatic tire 1, a plurality of blocks (center blocks 40C and edge blocks 40M) are formed by a circumferential grooves (center side main grooves 10C and edge side main grooves 10S) extended in the tire circumferential direction TC, and lateral grooves (lateral grooves 30C and lateral grooves 30M) extended in a tread width direction TW. The length of the blocks along the tire circumferential direction TC is longer than the width of the lateral grooves along the tire circumferential direction TC. Narrow grooves 50, which are extended along the tread width direction TW, are recessed inward in a tire radial direction, and are narrower than the lateral grooves 30C, are formed in bottom sections 31 of the lateral grooves 30C, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire in which a plurality of blocks are formed by a circumferential groove extending in a tire circumferential direction and a lateral groove extending in a tread width direction.

  Conventionally, in a pneumatic tire (hereinafter referred to as a tire) mounted on a vehicle such as a truck, a tread pattern in which a plurality of blocks are formed by a circumferential groove extending in the tire circumferential direction and a lateral groove extending in the tread width direction is widely used. Has been.

  In such a tire, in order to improve driving performance by increasing an edge component on irregular roads, snowy roads, and the like, for example, a sipe that is recessed radially inward in the tire radial direction is formed (for example, a patent) Reference 1).

JP 2001-187517 A (first page, FIGS. 1 to 3)

  However, the conventional tire described above has the following problems. That is, when the block contacts the road surface in the dry road, the sipe formed near the block is closed. That is, the bottom (so-called base rubber) of the lateral groove between the block in contact with the road surface (hereinafter referred to as a grounding block) and the block adjacent to the rear in the tire rotation direction of the grounding block (hereinafter referred to as the rear block) is continuous in the tire circumferential direction. It will be in the state.

  For this reason, when the grounding block falls backward in the tire rotation direction, the base rubber propagates the fall of the grounding block to the rear block, and the rear block also falls backward in the tire rotation direction. As a result, the stepped portion of the rear block is displaced rearward in the tire rotation direction, and the driving force is concentrated on the stepped portion. Accordingly, there is a problem in that wear (for example, heel and toe wear) of the stepped portion of the entire block easily proceeds, and wear resistance is deteriorated.

  In particular, in a tire in which the length of the block along the tire circumferential direction is longer than the width of the lateral groove along the tire circumferential direction (lateral groove width), the blocks adjacent to each other in the tire circumferential direction are close to each other. Is easily transmitted to the rear block through the base rubber, and the wear resistance is remarkably deteriorated.

  In view of this, the present invention more reliably reduces the wear resistance while ensuring driving performance when the length of the block along the tire circumferential direction is longer than the width of the transverse groove along the tire circumferential direction. The object is to provide a tire that can be easily suppressed.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that circumferential grooves (center side main groove 10C and end side main groove 10S) extending in the tire circumferential direction (tire circumferential direction TC), and tread width direction (tread width direction TW). A plurality of blocks (a central block 40C and an end block 40M) are formed by the lateral grooves (lateral grooves 30C and 30M) extending in the length direction, and the lengths of the blocks in the tire circumferential direction (the central block circumferential length L1 and the end block) The circumferential length L5) is a tire (pneumatic tire 1) longer than the width of the lateral groove along the tire circumferential direction (lateral groove width L2 and lateral groove width L6), and the bottom (bottom 31) of the lateral groove is The gist is that a narrow groove (for example, a narrow groove 50) that extends along the tread width direction and is recessed inside the tire radial direction (tire radial direction TR) and thinner than the lateral groove is formed.

  According to this feature, a narrow groove is formed at the bottom of the block. According to this, as compared with a tire in which a narrow groove is not formed, an edge component is increased on an irregular road, a snowy road, etc., and driving performance can be secured.

  Further, since the narrow groove is thicker than the conventional sipe, even if the block contacts the road surface in the dry road, the narrow groove formed in the vicinity of the block does not close. That is, the bottom of the lateral groove (so-called base rubber) between the block in contact with the road surface (hereinafter referred to as a grounding block) and the block adjacent to the rear of the grounding block in the tire rotation direction (hereinafter referred to as the rear block) is in the tire circumferential direction. It becomes a discontinuous state. For this reason, the narrow groove can block the falling of the grounding block to the rear in the tire rotation direction. Thereby, the tread surface of the rear block is easily in contact with the road surface without the stepped portion of the rear block being displaced rearward in the tire rotation direction. Therefore, it is possible to more reliably suppress the deterioration of the wear resistance without concentrating the driving force only on the stepping portion.

  Thus, according to the tire of the present invention, when the length of the block along the tire circumferential direction is longer than the width of the lateral groove along the tire circumferential direction, wear resistance is ensured while ensuring driving performance. Sexual deterioration can be suppressed more reliably.

  A second feature of the present invention relates to the first feature of the present invention, wherein the length of the narrow groove along the tire circumferential direction (thin groove width L7) is such that a normal internal pressure and a normal load are applied to the tire. The gist is that it is a width that forms a gap in a state where it is in contact with the road surface during tire rolling.

  Here, the normal internal pressure is the air pressure corresponding to the maximum load capacity of the Year Book 2008 version of JATMA (Japan Automobile Tire Association). The load corresponds to the maximum load capacity when a wheel is applied. Outside Japan, the normal internal pressure is the air pressure corresponding to the maximum load (maximum load capacity) of a single wheel described in the standard described later, and the normal load is the application size described in the standard described later. It is the maximum load (maximum load capacity) of a single wheel. 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”.

  A third feature of the present invention relates to the first or second feature of the present invention, wherein the length of the narrow groove along the tread width direction (thin groove length L3) is along the tread width direction of the block. The gist is that it is equal to or greater than the width (central block width L4).

  A fourth feature of the present invention relates to the first to third features of the present invention, wherein the width of the narrow groove along the tire circumferential direction is 10 to 50% of the width of the lateral groove along the tire circumferential direction. The tire according to any one of claims 1 to 3.

  The fifth feature of the present invention is related to the first to fourth features of the present invention, and the depth along the tire radial direction of the narrow groove (thin groove depth D1) is 10 mm or less. To do.

  A sixth feature of the present invention relates to the first to fifth features of the present invention, wherein the length of the block along the tire circumferential direction is 3 to 10 times the width of the transverse groove along the tire circumferential direction. It is a summary.

  A seventh feature of the present invention relates to the first to sixth features of the present invention, wherein the narrow groove has a first detail (first detail 51) formed near the bottom of the lateral groove, and the first detail. A second detail (second detail 52) formed on the inner side in the tire radial direction than the first detail width L1 along the tire circumferential direction of the first detail (first detail width L71). The gist is that the width differs from the width along the circumferential direction (second detail width L72).

  An eighth feature of the present invention relates to the seventh feature of the present invention, wherein a width of the first detail along the tire circumferential direction is shorter than a width of the second detail along the tire circumferential direction. The gist.

  A ninth feature of the present invention is according to the seventh or eighth feature of the present invention, wherein the second detail is formed in an arc shape in a cross section perpendicular to the extending direction of the narrow groove. To do.

  A tenth feature of the present invention relates to the first to ninth features of the present invention, and is summarized in that the narrow groove is formed in a zigzag shape in a cross section perpendicular to the extending direction of the narrow groove. .

  An eleventh feature of the present invention relates to the first to tenth features of the present invention, and is summarized in that the narrow groove is formed in a zigzag shape in a tread surface view.

  According to the feature of the present invention, when the length of the block along the tire circumferential direction is longer than the width of the lateral groove along the tire circumferential direction, the wear resistance is deteriorated while ensuring the driving performance. A tire that can be more reliably suppressed can be provided.

FIG. 1 is a perspective view showing a part of a pneumatic tire 1 according to this embodiment. FIG. 2 is a developed plan view showing a tread pattern of the pneumatic tire 1 according to the present embodiment. FIG. 3 is a cross-sectional view showing a part of the central land portion row 20C along F3-F3 of FIG. FIG. 4 is a cross-sectional view illustrating a part of the central land portion row 20C according to the first modification. FIG. 5 is a cross-sectional view illustrating a part of the central land portion row 20C according to the second modification. FIG. 6A is a developed plan view (tread surface view) showing a tread pattern in the vicinity of the central land portion row 20C according to the third modification. FIG. 6B is a cross-sectional view (F3-F3 cross-sectional view of FIG. 2) showing a part of the central land portion row 20C according to the third modification. FIG. 7 is a schematic diagram showing a state where the central land portion row 20C according to the present embodiment is grounded to the road surface.

  Next, an embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. Specifically, (1) Configuration of pneumatic tire, (2) Configuration of narrow groove, (3) Modified example, (4) Comparative evaluation, (5) Action and effect, (6) Other embodiments will be described. To do.

  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.

(1) Configuration of Pneumatic Tire First, the configuration of the pneumatic tire 1 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing a part of a pneumatic tire 1 according to this embodiment. FIG. 2 is a developed plan view showing a tread pattern of the pneumatic tire 1 according to the present embodiment. The pneumatic tire 1 may be filled with an inert gas such as nitrogen gas instead of air.

  As shown in FIGS. 1 and 2, a land portion row is formed in the pneumatic tire 1 by a circumferential groove extending in the tire circumferential direction TC.

  Specifically, the circumferential groove is configured by a pair of central-side main grooves 10C and a pair of end-side main grooves 10S. The center side main groove 10C is formed closer to the tire equator line CL than the end side main groove 10S. The end-side main groove 10S is formed outside the center-side main groove 10C in the tread width direction TW.

  On the other hand, the land portion row includes a central land portion row 20C, a pair of adjacent land portion rows 20M, and a pair of outer end land portion rows 20S.

  The central land portion row 20C is located on the tire equator line CL and is provided between the pair of central-side main grooves 10C. The central land portion row 20C is configured by providing a plurality of central blocks 40C along the tire circumferential direction TC. The central block 40C is formed by a pair of central main grooves 10C and a plurality of lateral grooves 30C extending in the tread width direction TW.

  The length of the central block 40C along the tire circumferential direction TC (hereinafter referred to as the central block circumferential length L1) is longer than the width of the lateral groove 30C along the tire circumferential direction TC (hereinafter referred to as the lateral groove width L2) (see FIG. 2). . The central block circumferential length L1 is preferably 3 to 10 times the lateral groove width L2.

  A narrow groove 50 extending linearly along the tread width direction TW is formed at the bottom 31 (see FIG. 3) of the lateral groove 30C. In the present embodiment, the length of the narrow groove 50 along the tread width direction TW (hereinafter referred to as the narrow groove length L3) is equal to the width along the tread width direction TW of the central block 40C (hereinafter referred to as the center block width L4). Are the same. The detailed configuration of the narrow groove 50 will be described later.

  The adjacent land portion row 20M is adjacent to the outer side of the central land portion row 20C in the tread width direction TW, and is provided between the center side main groove 10C and the end side main groove 10S. The adjacent land portion row 20M is configured by providing a plurality of end blocks 40M along the tire circumferential direction TC. The end block 40M is formed by the central main groove 10C, the end main groove 10S, and a plurality of lateral grooves 30M extending in the tread width direction TW.

  The length of the end block 40M along the tire circumferential direction TC (hereinafter referred to as end block circumferential length L5) is longer than the width of the lateral groove 30M along the tire circumferential direction TC (hereinafter referred to as lateral groove width L6) (FIG. 2). reference). The end block circumferential length L5 is preferably 3 to 10 times the lateral groove width L6.

  The outer end land portion row 20S is adjacent to the outer side of the adjacent land portion row 20M in the tread width direction TW, and is provided on the outer side of the end portion main groove 10S in the tread width direction TW. The outer end land portion row 20S is formed in a rib shape extending continuously in the tire circumferential direction TC.

(2) Structure of narrow groove Next, the detailed structure of the narrow groove 50 mentioned above is demonstrated, referring FIG. FIG. 3 is a cross-sectional view showing a part of the central land portion row 20C along F3-F3 of FIG. That is, FIG. 3 is a cross-sectional view orthogonal to the extending direction of the narrow groove 50.

  As shown in FIG. 3, the narrow groove 50 is recessed from the bottom 31 of the lateral groove 30C toward the inside in the tire radial direction TR and is formed narrower than the lateral groove 30C. The narrow groove 50 extends linearly along the narrow groove center line DL. Note that the narrow groove center line DL indicates a line extending in the tire radial direction TR through the center in the tire circumferential direction TC of the lateral groove 30C in the cross-sectional view of FIG.

  The width of the narrow groove 50 along the tire circumferential direction TC (hereinafter referred to as the narrow groove width L7) is a gap in a state where a normal internal pressure and a normal load are applied to the pneumatic tire 1 and in contact with the road surface during tire rolling. Is the width to form. The narrow groove width L7 is preferably 10 to 50%, particularly 20 to 40% of the lateral groove width L2. The narrow groove width L7 does not change in the tire radial direction TR.

  Further, the depth of the narrow groove 50 along the tire radial direction TR (hereinafter referred to as the narrow groove depth D1) is shallower than the depth of the lateral groove 30C along the tire radial direction TR (hereinafter referred to as the lateral groove depth D2). The narrow groove depth D1 is 5 to 90% of the lateral groove depth D2. In particular, the narrow groove depth D1 is preferably 10 mm or less.

(3) Modification Example Next, a modification example of the narrow groove 50 according to the embodiment described above will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part as the fine groove 50 which concerns on embodiment mentioned above, and a different part is mainly demonstrated.

(3-1) Modification 1
First, the configuration of the narrow groove 50A according to Modification 1 will be described with reference to the drawings. FIG. 4 is a cross-sectional view (F3-F3 cross-sectional view of FIG. 2) showing a part of the central land row 20C according to the first modification.

  In the embodiment described above, the narrow groove width L7 does not change in the tire radial direction TR. On the other hand, in the first modification, the width of the narrow groove 50A along the tire circumferential direction TC changes in the tire radial direction TR.

  As shown in FIG. 4, the narrow groove 50 </ b> A includes a first detail 51 and a second detail 52. The first details 51 are formed near the bottom 31 of the lateral groove 30 </ b> C and open to the bottom 31. On the other hand, the second detail 52 is formed on the inner side in the tire radial direction TR than the first detail 51. The second detail 52 is formed in an arc shape in the cross-sectional view of FIG.

  That is, the width of the first detail 51 along the tire circumferential direction TC (hereinafter referred to as the first detail width L71) is different from the width of the second detail 52 along the tire radial direction (hereinafter referred to as the second detail width L72). The first detail width L71 is shorter than the second detail width L72.

  Here, in the cross-sectional view of FIG. 4, the second detail 52 is not necessarily formed in an arc shape, and may be, for example, a square shape. Further, the first detail width L71 is not necessarily shorter than the second detail width L72, and may be longer than the second detail width L72, for example.

(3-2) Modification 2
Next, the configuration of the narrow groove 50B according to Modification 2 will be described with reference to the drawings. FIG. 5 is a cross-sectional view (F3-F3 cross-sectional view of FIG. 2) showing a part of the central land portion row 20C according to the second modification.

  In the embodiment described above, the narrow groove 50 extends linearly along the narrow groove center line DL. On the other hand, in the modified example 2, the narrow groove 50B is not along the narrow groove center line DL.

  As shown in FIG. 5, the narrow groove 50 </ b> B includes a first detail 51 and a second detail 52, as in the first modification. The first detail 51 and the second detail 52 are inclined with respect to the narrow groove center line DL and connected to each other.

  Here, the first detail 51 and the second detail 52 may be repeatedly arranged along the tire radial direction TR. That is, the narrow groove 50B may be formed in a zigzag shape in the tire radial direction TR. In this case, the zigzag amplitude is preferably smaller than the lateral groove width L2.

  Further, the narrow groove 50B is not necessarily formed in a zigzag shape in the tire radial direction TR, and may be formed in a wave shape in the tire radial direction TR, for example. Even in this case, the wavy amplitude is preferably smaller than the lateral groove width L2.

(3-2) Modification 3
Next, the configuration of the narrow groove 50C according to Modification 3 will be described with reference to the drawings. FIG. 6A is a developed plan view (tread surface view) showing a tread pattern in the vicinity of the central land portion row 20C according to the third modification. FIG. 6B is a cross-sectional view (F3-F3 cross-sectional view of FIG. 2) showing a part of the central land portion row 20C according to the third modification.

  In the embodiment described above, the narrow groove 50 extends linearly along the tread width direction TW. On the other hand, in the third modification, the narrow groove 50C does not extend linearly along the tread width direction TW. The narrow groove width L7 indicates a width orthogonal to the extending direction of the narrow groove 50C.

  As shown in FIG. 6A, the narrow groove 50C is formed in a zigzag shape in the tread width direction TW. In this case, the zigzag amplitude is preferably smaller than the lateral groove width L2. As shown in FIG. 6B, the narrow groove 50C extends linearly along the narrow groove center line DL in the same manner as the narrow groove 50 described in the embodiment.

  Here, the narrow groove 50C does not need to be formed in a zigzag shape in the tread width direction TW, and may be formed in a wave shape in the tread width direction TW, for example. Further, the narrow groove 50C does not necessarily extend linearly along the narrow groove center line DL, and includes the configuration of the narrow groove 50A described in Modification 1 and the narrow groove 50B described in Modification 2. You may go out.

(4) Comparative Evaluation Next, in order to further clarify the effect of the present invention, comparative evaluation performed using pneumatic tires according to the following comparative examples and examples will be described. Specifically, (5-1) Configuration of each pneumatic tire and (5-2) Evaluation result will be described. In addition, this invention is not limited at all by these examples.

(4-1) Configuration of Each Pneumatic Tire First, a pneumatic tire according to a comparative example and Examples 1 to 4 will be briefly described. In addition, the data regarding each pneumatic tire were measured on the conditions shown below.

・ Tire size: 295 / 75R22.5
・ Internal pressure condition: 650kPa
In the pneumatic tire according to the comparative example, the sipe described in the background art is formed at the bottom of the lateral groove. That is, the sipe is closed when the block contacts the road surface. In the pneumatic tire according to Example 1, the narrow groove 50 described in the embodiment is formed in the bottom 31 of the lateral groove 30C (see FIGS. 1 to 3). In the pneumatic tire according to the second embodiment, the narrow groove 50A described in the first modification is formed on the bottom 31 of the lateral groove 30C (see FIG. 4). In the pneumatic tire according to the third embodiment, the narrow groove 50B described in the second modification is formed at the bottom 31 of the lateral groove 30C (see FIG. 5). In the pneumatic tire according to the fourth embodiment, the narrow groove 50C described in the third modification is formed on the bottom 31 of the lateral groove 30C (see FIG. 6).

(4-2) Evaluation Results Next, the evaluation results of the wear resistance of each pneumatic tire will be described with reference to Table 1.

  After running 50,000 km on a vehicle equipped with each pneumatic tire, the wear amount of the pneumatic tire according to the comparative example (reduction amount worn from the time of new article) is set to “100”, and the wear amounts of other pneumatic tires are compared. evaluated. In addition, the larger the index, the smaller the amount of wear and the better the wear resistance. As a result, as shown in Table 1, it was found that the pneumatic tires according to Examples 1 to 4 were superior in wear resistance as compared to the pneumatic tire according to the comparative example.

(5) Action / Effect In the embodiment, the narrow groove 50 is formed in the bottom 31 of the lateral groove 30C. According to this, as compared with a pneumatic tire in which the narrow groove 50 is not formed, an edge component is increased on an irregular road, a snowy road, etc., and driving performance can be secured.

Further, since the narrow groove 50 is thicker than the conventional sipe, even if the central block 40C is in contact with the road surface in the dry road, the narrow groove 50 formed in the vicinity of the central block 40C is not closed. That is, the narrow groove width L7 is a width that forms a gap in a state where a normal load is applied to the pneumatic tire 1 and in contact with the road surface. According to this, as shown in FIG. 7, the central block 40C in contact with the road surface (hereinafter, ground block 40C ₁₎ and the central block 40C (hereinafter adjacent in the tire rotation direction R behind the ground block 40C _1, the rear block 40C ₂ ), the bottom 31 (so-called base rubber) of the lateral groove 30C is discontinuous in the tire circumferential direction TC. Therefore, narrow groove 50, can block leaning in the tire rotation direction R behind the ground block 40C _1. Thus, without depression portion 41 of the rear block 40C ₂ is shifted in the tire rotation direction R behind, tread of the rear block 40C ₂ is likely contact with the road surface smoothly. Therefore, it is possible to more reliably suppress the deterioration of the wear resistance without concentrating the driving force only on the stepping portion 41.

  Each of the central block circumferential length L1 and the end block circumferential length L5 is longer than the lateral groove width L2 and the lateral groove width L6. According to this, it becomes easier to exhibit the above-described effect of suppressing wear resistance. If the center block circumferential length L1 and the end block circumferential length L5 are shorter than the lateral groove width L2 and the lateral groove width L6, the blocks adjacent to each other in the tire circumferential direction TC are far away from each other. Difficult to propagate to.

  Thus, according to the pneumatic tire 1 according to the embodiment, when the central block circumferential length L1 and the end block circumferential length L5 are formed longer than the lateral groove width L2 and the lateral groove width L6, the driving performance is ensured. However, deterioration of wear resistance can be more reliably suppressed.

In the embodiment, the narrow groove length L3 is the same as the central block width L4. According to this, the narrow groove 50, can be reliably cut off the leaning in the tire rotation direction R behind the ground block 40C _1. For this reason, since the stepping portion 41 does not shift rearward in the tire rotation direction R, it is possible to reliably prevent the driving force from concentrating only on the stepping portion 41.

In the embodiment, the narrow groove width L7 is 10 to 50% (particularly 20 to 40%) of the lateral groove width L2. Incidentally, when the narrow groove width L7 is less than 10 percent of the lateral groove width L2, the thin groove 50 is easily closed, it may be difficult to cut off the leaning in the tire rotation direction R behind the ground block 40C _1. On the other hand, if the narrow groove width L7 is larger than 50% of the lateral groove width L2, the rigidity of the entire central block 40C is excessively lowered, and the driving performance may be deteriorated.

In the embodiment, the narrow groove depth D1 is 5 to 90% of the lateral groove depth D2. Incidentally, when the narrow groove depth D1 is shallower than 5% of the lateral groove depth D2, the base rubber becomes thicker, it may be difficult to cut off the leaning in the tire rotation direction R behind the ground block 40C _1. On the other hand, if the narrow groove depth D1 is deeper than 90% of the lateral groove depth D2, the rigidity of the entire central block 40C is excessively lowered, and the driving performance may be deteriorated.

  In the first modification, the first detail width L71 is shorter than the second detail width L72. The second details 52 are formed in an arc shape in the cross-sectional view of FIG. According to this, even when stress is concentrated on the bottom of the second detail 52, it is possible to achieve both driving performance and wear resistance while preventing cracks and the like from occurring at the bottom of the second detail 52.

  In the second modification, the narrow groove 50B is formed in a zigzag shape in the tire radial direction TR. In the third modification, the narrow groove 50C is formed in a zigzag shape in the tread width direction TW. According to this, when a longitudinal force or a lateral force is applied to the entire pneumatic tire 1, it is possible to prevent at least a part of the narrow groove 50B from being closed and the rigidity of the entire central block 40C from being excessively lowered. For this reason, while being able to ensure drive performance, the fall of various performances, such as steering stability, braking performance, and cornering property, can be controlled more reliably.

  Here, in the modified example 2, when the narrow groove 50B is formed in a zigzag shape in the tire radial direction TR, it is preferable that the zigzag amplitude is smaller than the lateral groove width L2. In the third modification, when the narrow groove 50C is formed in a zigzag shape in the tread width direction TW, the zigzag amplitude is preferably smaller than the lateral groove width L2. In addition, if each zigzag amplitude is larger than the lateral groove width L2, the rigidity of the entire central block 40C may be excessively lowered, and drive performance may be deteriorated.

(6) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments 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, the embodiment of the present invention can be modified as follows. Specifically, the tire has been described as the pneumatic tire 1 filled with air, nitrogen gas, or the like, but is not limited thereto, and may be a solid tire (no puncture tire). Of course, the configuration and the tread pattern of the pneumatic tire 1 can be appropriately set according to the purpose.

  Further, the shape, configuration, dimensions, ratio, and the like of the narrow groove 50 (the narrow groove 50A, the narrow groove 50B, and the narrow groove 50C) are not limited to those described in the embodiment, and are appropriately set according to the purpose. Of course you can.

  For example, the narrow groove length L3 has been described as being the same as the central block width L4, but is not limited thereto, and may be shorter than the central block width L4 or longer than the central block width L4. May be. Moreover, although the horizontal groove was demonstrated as what is formed in the central land part row | line 20C and the adjacent land part row | line | column 20M, it is not limited to this, You may be formed in the outer end land part row | line | column 20S. Further, although the narrow groove 50 has been described as being provided at the bottom 31 of the lateral groove 30C, the present invention is not limited to this. For example, the narrow groove 50 is provided at the bottom of the lateral groove 30M or the bottom of the lateral groove forming the outer end block. It may be.

  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 1 ... Pneumatic tire, 10C ... Central side main groove, 10S ... End side main groove, 20C ... Central land part row, 20M ... Adjacent land portion row, 20S ... Outer end land portion row, 30C ... Horizontal groove, 30M ... Horizontal groove , 31 ... bottom part, 40C ... center block, 40C ₁ ... grounding block, 40C ₂ ... rear block, 40M ... block, 41 ... stepping part, 50 (50A-50C) ... narrow groove, 51 ... first detail, 52 ... first 2 details

Claims (11)

A plurality of blocks are formed by a circumferential groove extending in the tire circumferential direction and a lateral groove extending in the tread width direction, and the length of the block along the tire circumferential direction is larger than the width of the lateral groove along the tire circumferential direction. A long tire,
A tire that extends along the tread width direction and has a narrow groove that is recessed inward in the tire radial direction and narrower than the lateral groove at the bottom of the lateral groove.   The width along the tire circumferential direction of the narrow groove is a width that forms a gap in a state in which a normal internal pressure and a normal load are applied to the tire and in contact with a road surface during tire rolling. Tires.   The tire according to claim 1 or 2, wherein a length along the tread width direction of the narrow groove is equal to or greater than a width along the tread width direction of the block.   The tire according to any one of claims 1 to 3, wherein a width of the narrow groove along the tire circumferential direction is 10 to 50% of a width of the lateral groove along the tire circumferential direction.   The tire according to any one of claims 1 to 4, wherein a depth along the tire radial direction of the narrow groove is 10 mm or less.   The tire according to any one of claims 1 to 5, wherein a length of the block along the tire circumferential direction is 3 to 10 times a width of the transverse groove along the tire circumferential direction. The narrow groove is
A first detail formed near the bottom of the transverse groove;
A second detail formed inside the tire radial direction from the first detail,
The tire according to any one of claims 1 to 6, wherein a width of the first detail along the tire circumferential direction is different from a width of the second detail along the tire circumferential direction.   The tire according to claim 7, wherein a width of the first detail along the tire circumferential direction is shorter than a width of the second detail along the tire circumferential direction.   The tire according to claim 7 or 8, wherein the second detail is formed in an arc shape in a cross section orthogonal to the extending direction of the narrow groove.   The tire according to any one of claims 1 to 9, wherein the narrow groove is formed in a zigzag shape in a cross section perpendicular to the extending direction of the narrow groove.   The tire according to any one of claims 1 to 10, wherein the narrow groove is formed in a zigzag shape in a tread surface view.

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