JP6068196B2 - tire - Google Patents

Description

  The present invention relates to a tire.

  Conventionally, in heavy-duty tires mounted on trucks, buses, construction vehicles, etc., in order to suppress wear on the tread, the tread pattern has been devised, for example, by adjusting the groove wall of the lug groove within a predetermined angle range. A method has been proposed (see, for example, Patent Document 1). Here, the demand for suppression of wear of heavy duty tires is increasing year by year, and the actual situation is that further improvement is desired.

JP 2006-213177 A

  Therefore, the present invention has been made in view of the above-described problems, and it is possible to reduce 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 object is to provide a tire.

  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 so as to be convex in the tire rotation direction, and the land portion is formed by a grounding surface that contacts the road surface and the width direction groove. An angle formed between the ground contact surface and the width side wall on the tire equator line side with respect to the bent portion, and the ground contact surface and the width direction side in the bent portion. DOO is The angle formed, and gist different.

  In the first feature of the present invention, on the side of the kicking end formed behind the land portion in the tire rotation direction, the tire surface rotates on the ground contact surface and the land portion on the tire equator line side with respect to the bent portion. An angle formed by the width direction side wall located rearward in the direction may be smaller than an angle formed by the ground contact surface and the width direction side wall in the bent portion.

  In the first feature of the present invention, an angle formed by the ground contact surface and the side wall in the width direction on the tire equator line side with respect to the bent portion on a stepping end portion side formed in front of the land portion in the tire rotation direction. May be larger than an angle formed by the ground contact surface and the side wall in the width direction in the bent portion.

  As described above, according to the present invention, it is possible to provide a tire capable of 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. it can.

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. Fig.5 (a) is sectional drawing in the tire width direction position A of the tire which concerns on 1st Embodiment of this invention. FIG.5 (b) is sectional drawing in the tire equator line CL of the tire which concerns on 1st Embodiment of this invention. FIG. 6 is a diagram for explaining effects that can be achieved by the tire according to the first embodiment of the present invention.

(First embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 3, the tire 1 which concerns on the 1st Embodiment of this invention is demonstrated. FIG. 1 shows a belt configuration of a tire according to this embodiment. In FIG. 2, the top view of a part of tread surface in the tire 1 which concerns on this embodiment is shown.

  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 a protective belt layer 11 including two protective belts 11 </ b> A / 11 </ b> B and two main crossing belts 12 </ b> A / 12 </ b> B in the tread portion 10. And a small crossing belt layer 13 including two small crossing belts 13A / 13B.

In the tire 1 according to the present embodiment, as shown in FIG. 2, the width direction groove 20 is bent so as to be convex in at least one tire rotation direction R on at least one side of the tire equator line CL. It has the bending part 50A / 50B comprised.

  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. Moreover, all the width direction grooves 20 may be configured to have the above-described bent portion, or only a predetermined width direction groove 20 may be configured to have the above-described bent portion.

  In the example of FIG. 2, the width direction groove 20 is continuous along the tire equator line CL, and is configured to bend in the tire rotation direction R along 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.

  Here, in the region near the end portion 10E in the tire width direction W on the tread surface, the inclination angle of the width direction groove 20 with respect to the tire width direction W may be configured to be gentle. In such a case, in the tire 1 according to the present embodiment, the land portion 40 has an arrow-shaped shape in a plan view of the tread surface as shown in FIG.

  Further, in the tire 1 according to the present embodiment, as shown in FIGS. 1 and 2, the bent portions 50A / 50B have a belt layer (that is, the smallest angle formed between the cord constituting the belt layer and the tire circumferential direction L) (that is, It may be provided in the vicinity of the position A in the tire width direction corresponding to the end of the small crossing belt 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. Therefore, when the tire 1 rotates, a force in the tire rotation direction R (driving force) is generated in the region A1, and the tire rotation direction R in the region A2. Since a force in the opposite direction (braking force) is generated, a shearing force is generated in the vicinity of the boundary between the region A1 and the region A2 (that is, in 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. Further, in the tire 1 according to the present embodiment, by providing the above-described bent portion 50A / 50B, as shown in FIG. 3, in the land portion 40, as compared with the case where the bent portion 50A / 50B is not provided. The generated force (driving force) F2 in the tire rotation direction R is increased.

  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.

  Here, in general, a tire is attached to a vehicle. When wear progresses to a predetermined depth, a use form in which a tire attached to a steered wheel is attached to a drive wheel is applied. Further, while the steering wheel can specify the tire rotation direction R, the drive wheel often cannot specify the tire rotation direction R. Therefore, when the tire rotation direction R of the tire 1 shown in FIG. 2 is reversed, a force (driving force) F2 in the tire rotation direction R becomes a force (braking force) F1 in the opposite direction to the tire rotation direction R. That is, when the tire rotation direction R of the tire 1 shown in FIG. 2 is reversed, a force (braking force) F1 in the direction opposite to the tire rotation direction R is increased.

  Assuming such a case, the tire 1 according to the present embodiment is configured as follows. Here, FIG. 4 is a cross-sectional perspective view of the land portion 40 along the tire equator line CL of the tire 1 according to the present embodiment. Moreover, Fig.5 (a) is sectional drawing of the land part 40 along the tire width direction position A corresponding to the edge part of the small crossing belt layer 13 of the tire 1 which concerns on this embodiment. FIG. 5B is a cross-sectional view of the land portion 40 along the tire equator line CL of the tire 1 according to this embodiment.

  As shown in FIGS. 4 to 5, the land portion 40 includes a ground surface 40 that contacts the road surface and width direction side walls 40 x and 40 y formed by the width direction grooves 20. The land portion 40 is more tire than the bent portions 50 </ b> A / 50 </ b> B. Angles θx1 and θy1 formed between the ground plane 40z and the width direction side walls 40x and 40y on the equator line CL side, and angles θx2 and θy2 formed between the ground plane 40z and the width direction side walls 40x and 40y at the bent portions 50A / 50B, Different.

  Specifically, the tire rotation direction R when the new tire 1 is mounted is the right direction as shown in FIG. When this direction is used as a reference, the land portion 40 includes a kicking end portion 41x formed behind the tire rotation direction R of the land portion 40 by the width direction groove 20 and a tire rotation direction of the land portion 40 by the width direction groove 20. And a stepping end portion 41y formed in front of R.

  Further, as shown in FIGS. 5A to 5B, on the side of the kicking end 41x formed on the rear side of the land portion 40 in the tire rotation direction R, on the tire equator line CL side than the bent portion 50A / 50B. The aforementioned angle θx2 is smaller than the angle θx1.

  On the other hand, the angle θy2 described above is larger than the angle θy1 on the tire equator line CL side than the bent portions 50A / 50B on the stepping end portion 41y side formed in front of the tire rotation direction R of the land portion 40.

  With the above-described configuration, when the wear of the land portion 40 proceeds by the depth D1 in the tire radial direction D, the tire 1 according to the present embodiment kicks in the region A on the tire equator line CL side with respect to the bent portion 50A / 50B. The magnitude | size in the tire circumferential direction L of the hollow (recessed part) formed in the output end part 41x side becomes small.

  Similarly, in the region A closer to the tire equator line CL than the bent portions 50A / 50B, the size in the tire circumferential direction L of the protruding portion (convex portion) formed on the stepping end portion 41y side becomes smaller.

  Here, FIG. 6 is a diagram illustrating a state in which the tire rotation direction R of the tire having undergone wear has been reversed. That is, FIG. 6 shows a state in which the wear of the land portion 40 has progressed by the depth D1, and as a result, the steering wheel is mounted on the drive wheel and the tire rotation direction R is reversed.

  As shown in FIG. 6, in the tire 1 according to the present embodiment, as a result of the wear of the land portion 40 progressing by the depth D1, the protrusion (in the region A closer to the tire equator line CL than the bent portion 50A / 50B) A convex part) and a hollow (concave part) become small. Therefore, according to the tire 1 according to the present embodiment, it occurs in the land portion 40 as compared with the case where the tire rotation direction R is mounted in the opposite direction without reducing the protrusion (projection) and the depression (recess). Force (braking force) F1 ′ in the direction opposite to the tire rotation direction R is suppressed.

  Therefore, according to the tire 1 according to the present embodiment, after the wear has progressed to the middle stage of wear (position of the depth D1), the steering wheel is attached to the drive wheel, and the tire rotation direction R is reversed. Even if it exists, the force (braking force) F1 'of the reverse direction of the tire rotation direction R which generate | occur | produces in the land part 40 becomes small. That is, even when the tire rotation direction R is reversed, the shearing force generated near the boundary between the region A1 and the region A2 (that is, the region near the end of the small crossing belt layer 13) can be reduced. it can.

  In addition, it is preferable that the depth D1 of the land part 40 prescribed | regulated as a middle stage of wear exists in the range of 20%-40% of the height D2 in the tire radial direction D of the land part 40.

  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 FIGS. 2 to 5 having the widthwise groove 20 having the bent portions 50A / 50B was used. Specifically, as the tire according to Example 1, radial tires having different θx2 (θy2) and θx1 (θy1) described above were used. As the tire according to Comparative Example 1, a radial tire having the width direction groove 20 having the bent portions 50A / 50B but having the same angle θx2 (θy2) and the angle θx1 (θy1) was used.

In this test, the size of all tires was “59 / 80R63”. That is, all tires were heavy duty tires. Further, in this test, the wear energy at the tire width direction position A shown in FIG. 2 was measured using a measuring apparatus described in Japanese Patent Laid-Open No. 7-63658. Specifically, using each tire, the wear energy in the early stage of wear was compared with the wear energy in the middle stage of wear. Table 1 shows the comparison results. In Table 1, when the wear energy is small and good, “◎” is indicated. When the wear energy is not so good but within the allowable range, “◯” is indicated, and the wear energy is within the allowable range. If it is outside, it is indicated as “x”.

  According to such a comparison result, the tire according to Example 1 having the configuration of the present invention has a large wear energy when the tire rotation direction is opposite to the initial wear compared to the tire according to Comparative Example 1. Reduced to

  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 groove 40, land portion 50 A, 50 B, 51 A 1, 51 A 2, 51 B 1, 51 B 2 bending portion 60 A 60 B flat portion 70 70 A 70 B thin circumferential direction Groove, 40z ... ground plane, 40x, 40y ... side wall in width direction, 41x ... kicking end, 41y ... stepping end

Claims (4)

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 width direction groove has a bent portion configured to be bent so as to be convex in at least one tire rotation direction on at least one side of the tire equator line,
The land portion has a ground surface that contacts the road surface, and a width direction side wall formed by the width direction groove,
Wherein the ground plane in the tire equator side than the bent portion and said width direction side wall and angle formed, and the ground plane and the width direction side wall and an angle formed in the bent portion, different Ri,
A plurality of belt layers are provided, and at least one of the bent portions is a tire width direction position corresponding to an end portion of the belt layer having a smallest angle between a cord constituting the belt layer and the tire circumferential direction. It is provided in the vicinity of
The vicinity of the position in the tire width direction is a tire width direction of the land portion centered on a point at a distance of 1/4 of the tire width direction length of the tire from the end portion of the tread portion in the tire width direction. A tire having a distance within 1/3 of the width of the tire. On the kicking end side formed on the rear of the land portion in the tire rotation direction,
The angle formed between the ground contact surface and the side wall in the tire rotation direction rearward of the land portion on the tire equator line side with respect to the bent portion is the ground surface and the width direction side wall in the bent portion. The tire according to claim 1, wherein the tire is smaller than an angle formed by. On the stepping end side formed in the tire rotation direction front of the land portion,
The angle formed between the ground contact surface and the width direction side wall on the tire equator line side with respect to the bent portion is larger than the angle formed between the ground contact surface and the width direction side wall in the bent portion. Item 3. The tire according to Item 1 or 2.   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 width direction groove has a bent portion configured to be bent so as to be convex in at least one tire rotation direction on at least one side of the tire equator line,
  The land portion has a ground surface that contacts the road surface, and a width direction side wall formed by the width direction groove,
  The angle formed by the ground contact surface and the width direction side wall on the tire equator line side than the bent portion is different from the angle formed by the ground contact surface and the width direction side wall at the bent portion,
  On the stepping end side formed in the tire rotation direction front of the land portion,
  The angle formed by the ground contact surface and the width direction side wall on the tire equator line side with respect to the bent portion is larger than the angle formed by the ground contact surface and the width direction side wall at the bent portion.
A tire characterized by that.

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