JP2014094668A - Tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce shearing force generated between an area in the vicinity of a tire equator line CL and an area in the vicinity of an end part in the tire width direction W, and furthermore to restrain progress of wear.SOLUTION: A tire 1 related to the present invention has in a tread section 10, a plurality of land sections 40 partitioned by: a circumferential directional groove 30 extending in a tire width direction W or the end part 10E of the tread section 10; and a width directional groove 20 constituted so that the length in the tire width direction W becomes 30% or more of the length of the tread section 10 in the tire width direction W. The width directional groove 20 has bending parts 52A and 52B constituted so as to bend in a direction opposite to at least one tire rotational direction R. In the land sections 40, a width directional narrow groove 100 extending in the tire width direction W on the tire equator line side more than the bending parts 52A abd 52B, in which an edge component of the width directional narrow groove 100 formed inside in the tire radial direction of the land sections 40, is larger than an edge component of the width directional narrow groove 100 formed on the grounding surface.

Description

  The present invention relates to a tire.

  Conventionally, in the tread portion 10, a protective belt layer 11 composed of two protective belts 11A / 11B from the outer side in the tire radial direction, a main intersecting belt layer 12 composed of two main intersecting belts 12A / 12B, and two small belts There is known a heavy load tire 1 having a small crossing belt layer 13 composed of crossing belts 13A / 13B (for example, Patent Document 1).

Japanese Patent No. 4677307

  In the tire 1 described above, in a region where the angle formed by the cord constituting the belt layer and the tire circumferential direction L is large, the belt tension is small, and thus the region is greatly contracted in the tire circumferential direction L. As a result, when the tire 1 rotates, a force in the tire rotation direction (driving force) is generated in a region near the tire equator line CL, and a direction opposite to the tire rotation direction in a region near the end in the tire width direction W. Therefore, a shearing force is generated near the boundary between the two regions.

  Further, as described above, when the portion having a large shearing force is included, the wear easily proceeds. Further, when the wear progresses, for example, when the height of the land portion is halved, the rigidity of the land portion is increased. As a result, the wear is further facilitated.

  Therefore, the present invention has been made in view of the above-described problems, and reduces the shear force generated between the region near the tire equator line CL and the region near the end in the tire width direction W, while wearing. It aims at providing the tire which can suppress progress of this.

  The first feature of the present invention is that, in the tread portion, a circumferential groove extending in the tire circumferential direction or an end portion of the tread portion in the tire width direction, and a length in the tire width direction of the tread portion in the tire width direction. A tire having a plurality of land portions partitioned by a widthwise groove extending in the tire width direction and configured to be 30% or more of the length of the tire, wherein the widthwise groove is a tire equator line At least one side has at least one bent portion configured to bend in a direction opposite to the tire rotation direction, and the land portion has the tire equator line side with respect to the tire equator line side. A width direction narrow groove extending in the width direction is formed, and the width formed on the inner side in the tire radial direction of the land portion with respect to an edge component of the width direction narrow groove formed on the ground contact surface of the land portion. And summarized in that the larger edge component of MukoHosomizo.

  In the first feature of the present invention, the widthwise narrow groove may be branched on the inner side in the tire radial direction from the ground contact surface. Moreover, the width direction narrow groove may be formed so as to intersect on the tire equator line.

  As described above, according to the present invention, the progress of wear is suppressed while reducing the shearing force generated between the region near the tire equator line CL and the region near the end in the tire width direction W. The tire which can be provided can be provided.

FIG. 1 is a diagram for explaining a belt configuration of a tire according to a first embodiment of the present invention. FIG. 2 is a plan view of a part of the tread surface in the tire according to the first embodiment of the present invention. Drawing 3 is a figure for explaining the effect which can be produced with the tire concerning a 1st embodiment of the present invention. FIG. 4 is a cross-sectional perspective view of a land portion along the tire equator line of the tire according to the first embodiment of the present invention.

(First embodiment of the present invention)
A tire 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. In the present embodiment, a heavy load tire 1 will be described as an example of the tire 1, but the present invention is not limited to such a tire.

  The tire 1 according to the present embodiment includes a plurality of belt layers. Specifically, as shown in FIG. 1, the tire 1 according to the present embodiment includes, in the tread portion 10, two main belts 11 and 11 of a protective belt layer including two protective belts 11 </ b> A / 11 </ b> B from the outer side in the tread radial direction. A main crossing belt layer 12 made of crossing belts 12A / 12B and a small crossing belt layer 13 made of two small crossing belts 13A / 13B are provided.

  Further, as shown in FIG. 2, the tire 1 according to the present embodiment includes, in the tread portion 10, a circumferential groove 30 extending in the tire circumferential direction L or an end portion 10 </ b> E in the tire width direction W of the tread portion 10 and a tire width. A plurality of land portions 40 partitioned by the widthwise grooves 20 extending in the direction W are provided.

  Here, for example, the circumferential groove 30 preferably has a groove width of 10 mm or less, and the width direction groove preferably has a width of 50 mm or less. The land portion 40 may be provided with one or a plurality of circumferential narrow grooves (sipes) extending in the circumferential direction of 50 mm or less. The depth in the tire radial direction of the circumferential narrow groove is shallower than the depth in the tire radial direction of the circumferential groove 30 and the width groove 20.

  In the tire 1 according to this embodiment, the length of the width direction groove 20 in the tire width direction W is configured to be 30% or more of the length W1 of the tread portion 10 in the tire width direction W. Furthermore, in the tire 1 according to the present embodiment, the pitch P of each land portion 40 (width direction groove 20) may be configured to be 50 mm or more.

  Further, in the tire 1 according to the present embodiment, as illustrated in FIG. 2, the width direction groove 20 is configured to bend in at least one side of the tire equator line CL in a direction opposite to at least one tire rotation direction R. It is comprised so that it may have the bending part 52A / 52B.

  In the example of FIG. 2, the width direction groove 20 has one bent portion 50A on the left side of the tire equator line CL, and has one bent portion 50B on the right side of the tire equator line CL.

  Here, the width direction groove 20 may have one bent portion 50A (or 50B) only on the left side (or right side) of the tire equator line CL.

  Here, by the above-described bent portions 50A / 50B, a recess (concave portion) is formed on at least one kicking side of the land portions 40 arranged on both sides of the tire equator line CL.

  Further, the above-described bent portions 50A / 50B form protrusions (projections) on at least one of the land portions 40 arranged on both sides of the tire equator line CL.

  As shown in FIG. 2, the tire 1 according to the present embodiment has a directional pattern that specifies the rotation direction R of the tire 1. That is, in the tire 1 according to the present embodiment, it is assumed that the mounting direction of the tire 1 with respect to the wheel is determined.

 In the tire 1 according to the present embodiment, the land portion 40 has an arrow-like shape in plan view of the tread surface as shown in FIG.

  Further, in the tire 1 according to the present embodiment, as shown in FIG. 2, the bent portions 50A / 50B have a belt layer (that is, a small crossing belt) having the smallest angle between the cord constituting the belt layer and the tire circumferential direction L. It is preferably provided in the vicinity of the position A in the tire width direction corresponding to the end of the layer 13). Here, “in the vicinity of the position A in the tire width direction” is, for example, a distance of 1/4 of the width of the tire 1 (the length in the tire width direction W) from the end portion 10E in the tire width direction W on the tread surface. It is a region having a distance within 1/3 of the width of the land portion 40 (the length in the tire width direction W) in the tire width direction W with the point as the center.

  For example, the length W3 in the tire width direction W between the tire width direction position A and the tire equator line CL may be about 1/4 of the length W1 of the tread portion 10 in the tire width direction W.

  In the tread portion 10 of the tire 1 according to the present embodiment, in the region A2 on the end side in the tire width direction W from the end portion of the small crossing belt layer 13, the tire equator line CL is more than the end portion of the small crossing belt layer 13. The angle formed by the cords constituting each belt layer and the tire circumferential direction L is larger than that of the side region A1.

  As a result, in the tread portion 10 of the tire 1, the region A2 on the end side in the tire width direction W from the end portion of the small crossing belt layer 13 is closer to the tire equator line CL side than the end portion of the small crossing belt layer 13. Compared with the region A1, the tire contracts in the tire circumferential direction L greatly.

  Therefore, when the tire 1 rotates, a force in the tire rotation direction R (driving force) is generated in the region A1, and a force (braking force) in the opposite direction to the tire rotation direction R is generated in the region A2. A shearing force is generated in the vicinity of the boundary between the region A1 and the region A2 (that is, the region near the end of the small crossing belt layer 13).

  Here, in the tire 1 according to the present embodiment, by providing the above-described bent portions 50A / 50B, as shown in FIG. 3, the land portion 40 is compared with a case in which the bent portions 50A / 50B are not provided. The force (braking force) F1 in the direction opposite to the tire rotation direction R generated in is reduced. As a result, the shear force generated near the boundary between the regions A1 and A2 (that is, the region near the end of the small crossing belt layer 13) can be reduced.

  In the present embodiment, the land portion 40 is formed with a width direction narrow groove 100 (width direction sipe) extending in the tire width direction W on the tire equator line CL side with respect to the bent portion 50A / 50B. In the present embodiment, an example is given in which the interval Lp in the tire circumferential direction L of the width direction narrow grooves 100 is equal to the pitch P of the land portion 40 (see FIG. 2).

  Specifically, as shown in FIG. 4, the width direction narrow groove 100 branches off in the tire radial direction D from the ground contact surface 40 z. That is, the width direction narrow groove 100 is formed in a Y shape in the cross section in the tire circumferential direction L and the tire radial direction D.

  In addition, it is preferable that the height Dz in the tire radial direction D of the land portion 40 and the depth D1 in the tire radial direction D from the contact surface 40z to the branching portion 110 satisfy the relationship of D1 = Dz ÷ 3. It is preferable that the depth D2 from the branch portion 110 to the groove bottom 120A / 120B of the width direction narrow groove 100 satisfies the relationship D2 = Dz ÷ 3. The length W1 (tread width) of the tread portion 10 in the tire width direction W and the tire width direction length Ws of the ground contact surface 40z of the width direction narrow groove 100 preferably satisfy the relationship of Ws = W1 ÷ 8. Moreover, it is preferable that the space | interval Lp in the tire circumferential direction L of the width direction fine groove 100 and the space | interval Ls between the groove bottom 120A of the width direction fine groove 100 and the groove bottom 120B satisfy | fill the relationship of Ls = Lp / 3.

  Further, according to the tire 1 according to the present embodiment, the width direction narrow groove 100 is branched at the branching portion 110. Therefore, the edge component increases as the number of the width direction narrow grooves 100 increases inside the tire radial direction D from the branching portion 110.

  Specifically, when the wear of the land portion 40 has progressed deeper than the depth D in the tire radial direction D, that is, when the wear has progressed further to the inside of the tire radial direction D than the branch portion 110 (in the middle of wear). Since the number of the width direction narrow grooves 100 increases, the progress of wear can be suppressed by further suppressing the rigidity of the land portion 40 in the region A1.

  As described above, according to the tire 1 according to the present embodiment, the progress of wear while reducing the shearing force generated between the region near the tire equator line CL and the region near the end in the tire width direction W. Can be suppressed.

(Modification 1)
Hereinafter, the tire 1 according to the first modification of the present invention will be described by focusing on the differences from the tire according to the first embodiment.

In the tire 1 according to the first modification, the width direction narrow groove 100A may be configured to be curved in a curved shape toward the inner side in the tire radial direction D on the inner side in the tire radial direction D than the branching portion 110. Good.

  Next, in order to clarify the effect of the present invention, results of tests performed using tires according to Comparative Example 1 and Example 1 will be described. In addition, this invention is not limited at all by these examples.

  In this experiment, as the tire according to Example 1, the radial tire shown in FIG. 2 having the width direction groove 20 having the bent portions 50A / 50B and the width direction narrow groove 100 is used, and the tire according to Comparative Example 1 is used. A radial tire having the widthwise groove 20 having the bent portions 50A / 50B but not having the widthwise narrow groove 100 was used.

  In this test, the size of all radial tires was “59 / 80R63”. That is, all tires were heavy duty tires. In this test, the wear energy at the tire width direction position A shown in FIG. 1 and the wear energy on the tire equator line CL were measured using a measuring apparatus described in JP-A-7-63658. The wear energy was measured at the time when the tires were not worn (initial stage), and at the middle stage when the wear of each tire progressed deeper than the depth D1.

  According to this measurement result, when new, the tire according to Example 1 having the configuration of the present invention has about 10% less wear energy at the tire width direction position A than the tire according to Comparative Example 1. In addition, the wear energy on the tire equator line CL was reduced by about 10%.

  Further, in the middle stage of wear, the tire according to Example 1 having the configuration of the present invention has a wear energy at the tire width direction position A reduced by about 15% as compared with the tire according to Comparative Example 1, and the tire equator line. The wear energy on CL was reduced by about 15%.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Tire, 10 ... Tread part, 11 ... Protection belt layer, 11A, 11B ... Protection belt, 12 ... Main crossing belt layer, 12A, 12B ... Main crossing belt, 13 ... Small crossing belt layer, 13A, 13B ... Small crossing Belt 20, width direction groove 30, circumferential direction groove 40, land portion 50 A, 50 B, bending portion 70, circumferential direction narrow groove 100, 100 A width direction narrow groove

Claims (3)

In the tread portion, a circumferential groove extending in the tire circumferential direction or an end portion of the tread portion in the tire width direction and a length in the tire width direction are 30% or more of a length of the tread portion in the tire width direction. A tire having a plurality of land portions partitioned by a widthwise groove extending in the tire width direction configured as described above,
The widthwise groove has a bent portion configured to bend in at least one side of the tire equator line in a direction opposite to at least one tire rotation direction,
In the land portion, a width direction narrow groove extending in the tire width direction is formed on the tire equator line side from the bent portion,
The edge component of the width direction narrow groove formed inside the tire radial direction of the land portion is larger than the edge component of the width direction narrow groove formed on the ground contact surface of the land portion. tire. 2. The tire according to claim 1, wherein the narrow groove in the width direction branches on the inner side in the tire radial direction from the ground contact surface. The tire according to claim 1 or 2, wherein the narrow groove in the width direction is formed so as to intersect the tire equator line.

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