JP2019182218A - Pneumatic tire - Google Patents

Abstract

To allow protrusions arranged on a buttress portion of a pneumatic tire to improve external damage resistance while securing traction performance.SOLUTION: A pneumatic tire 1 comprises protrusions 21 disposed on a buttress portion 3. The protrusion 21 comprises: side walls 22 protruding from a surface 3a of the buttress portion 3; and a top wall 23 disposed at a tip of the side walls 22. The top wall 23 is inclined in the tire radial direction so that a protrusion height H, which is a distance from a surface 3a of the buttress part 3, is lowered as approaching from the outer side to the inner side in the tire radial direction.SELECTED DRAWING: Figure 4A

Description

  The present invention relates to a pneumatic tire.

  A pneumatic tire having a buttress portion provided with a protrusion is known (see Patent Documents 1 and 2). In general, this type of protrusion is intended to improve traction performance when traveling on rough unpaved roads and rough roads such as rocky places.

JP 2013-82262 A JP 2015-168301 A

  As one of trauma failure modes when traveling on rough roads, a laceration of the buttress portion at the base of the protrusion is known.

  However, the conventional pneumatic tires, including those disclosed in Patent Documents 1 and 2, improve the trauma resistance while securing the traction performance of the protrusions provided on the buttress portion of the pneumatic tire. There is room for improvement.

  An object of the present invention is to improve the trauma resistance while securing the traction performance of the protrusion provided on the buttress portion of the pneumatic tire.

  One aspect of the present invention includes a protrusion provided on a padless portion, and the protrusion includes a side wall protruding from a surface of the buttress portion, and a top wall provided at a tip of the side wall. A pneumatic tire is provided that is inclined in the tire radial direction so that a protrusion height, which is a distance from the surface of the buttress portion, decreases from the outer side to the inner side in the tire radial direction.

  By providing the protrusion on the buttress portion, the traction performance is improved.

  The top wall of the protrusion is inclined in the tire radial direction so that the protrusion height decreases from the outside in the tire radial direction toward the inside. Therefore, the protrusion height is relatively high in the outer region of the protrusion in the tire radial direction, and the protrusion height is relatively low in the inner region of the protrusion in the tire radial direction. The protrusion height is relatively high in the area outside the tire radial direction of the protrusion, so that the protrusion effectively cooperates with the area near the end in the tire width direction (tread edge) of the tread pattern. This effectively improves the traction performance. In the region inside the tire radial direction of the protrusion, the protrusion height can be reduced by setting the protrusion height low. As a result, the movement of the protrusion when kicking out can be suppressed, and the damage resistance of the protrusion can be improved.

  Both of the pair of portions facing the tire circumferential direction of the side wall may be triangular.

  The pair of portions facing the tire circumferential direction of the side wall may be a triangle having the same shape and size.

  Of the pair of portions of the side wall facing the tire circumferential direction, one triangular area may be smaller than the other triangular area.

  By setting the rotation direction of the pneumatic tire so that the smaller area of the pair of portions in the tire circumferential direction of the side wall is the kicking side, the pneumatic tire is such that the larger area is the kicking side The movement of the protrusion at the time of kicking out can be suppressed as compared with the case where the rotation direction is set. As a result, the damage resistance of the protrusion is improved.

  Of the pair of portions of the side wall facing the tire circumferential direction, the triangular shape of one portion may have the same length as the triangular shape of the other portion and the bottom may be low.

  Of the pair of portions facing the tire circumferential direction of the side wall, the triangular shape of one portion may be similar to the triangular shape of the other portion and may have a small size.

  The outer end and the inner end of the protrusion in the tire radial direction can be provided in a range of 0.1 to 1.0 times the tire height from the innermost end of the pneumatic tire.

  The pneumatic tire includes a block extending from the tread portion to the buttress portion beyond the tread end, and the protrusion is arranged so that the outer end is adjacent to the inner end of the block in the tire radial direction. Also good.

  The block includes a first block in which an edge constituted by a portion extending in the tire width direction and a portion extending in the tire radial direction is located at a first position, and a portion extending in the tire width direction and a portion extending in the tire radial direction. A second block located at a second position on the center side in the tire width direction with respect to the first position, and the first block and the second block are alternately arranged in the tire circumferential direction. May be.

  A step is formed in the tire circumferential direction by the edge of the first block and the edge of the second block. The first and second blocks that form such a step and the protrusion cooperate to further improve the traction performance.

  ADVANTAGE OF THE INVENTION According to this invention, with respect to the protrusion provided in the buttress part of the pneumatic tire, it is possible to improve the damage resistance while ensuring the traction performance.

The meridian sectional view of the pneumatic tire concerning a 1st embodiment of the present invention. The partial expanded view of the tread part and buttress part of the pneumatic tire which concerns on 1st Embodiment of this invention. The partial side view of the buttress part in 1st Embodiment of this invention. The perspective view of the processus | protrusion in 1st Embodiment of this invention. The figure seen from the tire width direction of the protrusion in 1st Embodiment of this invention. The figure seen from the one side of the tire peripheral direction of the protrusion in 1st Embodiment of this invention. The figure seen from the other side of the tire peripheral direction of the protrusion in 1st Embodiment of this invention. The perspective view of the protrusion in 2nd Embodiment of this invention. The figure seen from the tire width direction of the protrusion in 2nd Embodiment of this invention. The figure seen from one side of the tire peripheral direction of the protrusion in 2nd Embodiment of this invention. The figure seen from the other side of the tire peripheral direction of the protrusion in 2nd Embodiment of this invention. The perspective view of the protrusion in 3rd Embodiment of this invention. The figure seen from the tire width direction of the protrusion in 3rd Embodiment of this invention. The figure seen from one side of the tire peripheral direction of the protrusion in 3rd Embodiment of this invention. The figure seen from the other side of the tire peripheral direction of the protrusion in 3rd Embodiment of this invention. The perspective view of the protrusion in 4th Embodiment of this invention.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In addition, the following description is only illustrations essentially and does not intend restrict | limiting this invention, its application thing, or its use. Further, the drawings are schematic, and the ratio of each dimension is different from the actual one.

  In the figure, the X direction is the tire radial direction, the Y direction is the tire circumferential direction, and the Z direction is the tire width direction.

(First embodiment)
Referring to FIG. 1, a pneumatic tire 1 includes a tread portion 2 and a pair of sides that respectively extend inward in the tire radial direction from both ends of the tread portion 2 in the tire width direction via a paddle portion 3 as a transition region. The wall portion 4 and a pair of bead portions 5 disposed at the inner ends in the tire radial direction of the pair of sidewall portions 4 are provided. The bead portion 5 includes an annular bead core 6 and a bead filler 7 disposed on the outer side in the tire radial direction of the bead core 6.

  Between the pair of bead portions 5, a toroidal carcass plus 8 is disposed inside the tread portion 2 and the sidewall portion 4 in the tire radial direction. An inner liner 9 is disposed inside the carcass plus 8 in the tire radial direction. In the tread portion 2, a belt layer 10 is provided outside the carcass plus 8 in the tire radial direction.

  Referring to FIGS. 2 and 3 together, blocks 11 </ b> A and 11 </ b> B extending from the tread portion 2 to the paddle portion 3 are provided in a region outside the tread portion 2 in the tire width direction. The blocks 11A and 11B are alternately arranged in the tire circumferential direction. Each of the blocks 11A and 11B includes a portion 11a extending in the tire width direction in the tread portion 2 and a portion 11b extending in the tire radial direction in the padless portion 3. These portions 11a and 11b constitute an edge 11c. In the present embodiment, the edge 11c constitutes the tread end 2a.

  The position of the edge 11c of the block 11B in the tire width direction (second position) is closer to the center in the tire width direction than the position of the edge 11c of the block 11A in the tire width direction (first position). Therefore, repeated steps are formed in the tire circumferential direction by the edge 11c of the block 11A and the edge 11c of the block portion 11B (staggered shoulder structure).

  A projection 21 that protrudes in the tire width direction is provided adjacent to each of the blocks 11 </ b> A and 11 </ b> B. The position and dimension at which the protrusion 21 is provided are not limited to the present embodiment. Specifically, the outer end and the inner end of the protrusion 21 in the tire radial direction are 0.1 times or more of the tire height WT from the innermost end 5a of the bead portion 5 which is the innermost end of the pneumatic tire 1. The position and dimensions of the protrusion 21 can be set so as to be in a range of 0 times or less.

  By providing the protrusion 21 on the buttress portion 3, the traction performance is improved. In particular, in the present embodiment, as described above, the protrusion 21 is provided adjacent to the blocks 11A and 11B in which the edge 11c forms a repeated step in the tire circumferential direction. The blocks 11A and 11B forming the step and the projection 21 cooperate to effectively improve the traction performance.

  Referring to FIGS. 4A to 4D, the protrusion 21 includes a side wall 22 that protrudes from the surface 3 a of the padless portion 3 in the tire width direction, and a top wall 23 provided at the tip of the side wall 22. An edge 24 is constituted by the side wall 22 and the top wall 23.

  In the present embodiment, the top wall 23 is a flat surface having a rectangular shape when viewed in the tire width direction. The top wall 23 is inclined in the tire radial direction so that the projection height H, which is the distance from the surface 3a of the buttress portion 3, decreases from the outer side toward the inner side in the tire radial direction. The direction of this inclination is conceptually indicated by an arrow Sr in FIG. 4A. In this embodiment, the projection height H at the inner end of the top wall 23 in the tire radial direction is zero. That is, the top wall 23 merges with the surface 3a of the buttress portion 3 at the inner end in the tire radial direction.

  The side wall 22 includes a pair of portions 22a and 22b facing each other in the tire circumferential direction, and a portion 22c constituting the outer end of the protrusion 21 in the tire radial direction. The pair of portions 22a and 22b facing each other in the tire circumferential direction is a flat surface extending so as to be orthogonal to the surface 3a of the padless portion 3 and the tire circumferential direction. Further, in the present embodiment, these portions 22a and 22b are right triangles having the same shape and dimensions, and an angle forming a right angle among the three corners is located outside in the tire radial direction. The portion 22c has a rectangular shape elongated in the tire circumferential direction.

  As described above, the top wall 23 in the tire radial direction has a protrusion height H that is inclined from the outer side to the inner side in the tire radial direction. However, the top wall 23 does not have an inclination in the tire circumferential direction, and is parallel to the surface 3 a of the padless portion 3 in the tire circumferential direction.

  Since the top wall 23 of the protrusion 21 is inclined in the tire radial direction so that the protrusion height H decreases from the outer side in the tire radial direction toward the inner side, in the region on the outer side in the tire radial direction of the protrusion 21, The protrusion height H is relatively high. In particular, the protrusion height H is the highest at the outer end of the protrusion 21 in the tire radial direction, that is, at the portion 22 c of the side wall 22. On the other hand, the protrusion height H is relatively low in the inner region of the protrusion 21 in the tire radial direction. In particular, as described above, the protrusion height H is zero at the inner end of the protrusion 21 in the tire radial direction.

  Since the protrusion height H is relatively high in the region outside the tire radial direction of the protrusion 21, the protrusion 21 effectively cooperates with the blocks 11A and 11B, thereby improving the traction performance more effectively.

  According to the knowledge obtained by the present inventor, there is a crack generated at the boundary between the side portion on the kick-out side and the surface of the buttress portion as a main failure or trauma of the protrusion provided on the buttress portion. For example, when the rotation direction of the pneumatic tire 1 is the direction indicated by the arrow R in the figure, the portion 22b of the pair of portions 22a and 22b facing the tire circumferential direction of the side wall 22 is the kicking side. By setting the projection height H low in the region inside the tire radial direction of the projection 21, the volume of the projection 21 can be reduced. As a result, the movement of the protrusion 21 in the portion 22b of the side wall 22 on the kick-out side can be suppressed, and thereby the damage resistance of the protrusion 21 can be improved.

  As described above, according to the pneumatic tire 1 according to the present embodiment, the trauma resistance can be improved while securing the traction performance of the protrusion 21 provided on the buttress portion 3.

  The pair of portions 22a and 22b facing in the tire circumferential direction may be, for example, a triangle other than a right triangle and a shape other than a right triangle such as a trapezoid. This also applies to the second and third embodiments described later.

  Hereinafter, second to fourth embodiments of the present invention will be described. The structures, operations, and functions not particularly mentioned in these embodiments are the same as those in the first embodiment. The same or similar elements as those in the first embodiment are denoted by the same reference numerals, and the description of the first embodiment relating to these elements and the drawings are also referred to.

(Second Embodiment)
5A to 5D show the protrusion 21 according to the second embodiment of the present invention. In this embodiment, a pair of parts 22a and 22b facing the tire circumferential direction of the side wall 22 of the protrusion 21 have different areas. Specifically, the area of the portion 22b is smaller than the area of the portion 22a. More specifically, the right triangles constituting the portions 22a and 22b have the same base length, but the height of the portion 22b is lower than that of the portion 22a.

  As in the first embodiment, the top wall 23 of the protrusion 21 of the present embodiment is inclined in the tire radial direction so that the protrusion height H decreases from the outer side to the inner side in the tire radial direction (arrows). Sr). In the present embodiment, as described above, the pair of portions 22a and 22b opposed to the tire circumferential direction of the side wall 22 have different areas, so that the top wall 23 of the protrusion 21 has a protrusion height H of the portion 22a. Inclined in the tire circumferential direction so as to decrease toward the portion 22b. The direction of this inclination is conceptually indicated by an arrow Sc in FIG. 5A.

  The top wall 23 is provided with an inclination in the tire radial direction (arrow Sr), and the protrusion height H is reduced in the region inside the tire radial direction of the protrusion 21 to reduce the volume of the protrusion 21. Can be improved.

  When the rotation direction of the pneumatic tire 1 is the direction indicated by the arrow R, that is, the portion 22b of the pair of portions 22a and 22b facing the tire circumferential direction of the side wall 22 is the kicking side. When the rotation direction of the pneumatic tire 1 is opposite to the arrow R, the portion 22a is on the kicking side. In the former case, the portion 22b of the side wall 22 on the kicking side has a small area and the projection height H is low, so that the portion 22a of the side wall 22 on the kicking side has a large area and the projection height H as in the latter case. Compared with the case where it is high, the movement of the protrusion 21 when kicking out can be suppressed. As a result, in the former case, the damage resistance of the protrusion 21 can be further improved.

(Third embodiment)
6A to 6D show a protrusion 21 according to a third embodiment of the present invention. In the present embodiment, the area of the portion 22b is smaller than the area of the portion 22a among the pair of portions 22a and 22b facing the tire circumferential direction of the side wall 22 of the protrusion 21. Specifically, the right triangles forming the portions 22a and 22b are similar in shape, but the portion 22b has a smaller dimension (including the length and height of the base) than the portion 22a.

  As in the second embodiment, the side wall 23 of the protrusion 21 of the present embodiment is inclined in the tire radial direction so that the protrusion height H decreases from the outer side in the tire radial direction toward the inner side (arrow Sr). The protrusion height is inclined in the tire circumferential direction (arrow Sc) so that the protrusion height decreases from the portion 22a toward the portion 22b.

  Similar to the first and second embodiments, in this embodiment, the damage resistance of the protrusions 21 can be improved by reducing the volume of the protrusions 21 by the inclination of the top wall 23 in the tire radial direction (arrow Sr). Similarly to the second embodiment, when the rotation direction of the pneumatic tire 1 is the direction of the arrow R, the portion 22b of the side wall 22 on the kicking side due to the inclination of the top wall 23 in the tire circumferential direction (arrow Sc) Even when the area is small and the protrusion height H is low, the damage resistance of the protrusion 21 can be improved.

(Fourth embodiment)
FIG. 7 shows a protrusion 21 according to a fourth embodiment of the present invention. In the present embodiment, the top wall 23 of the protrusion 21 is inclined in the tire radial direction so that the protrusion height H decreases from the outer side to the inner side in the tire radial direction (arrow Sr), but in the tire circumferential direction. Has no slope.

  In the first to third embodiments, the pair of portions 22a and 22b facing the tire circumferential direction of the side wall 22 of the protrusion 21 are inclined in the tire circumferential direction. Specifically, the portions 22a and 22b are inclined in the tire circumferential direction so that the protrusion height H gradually decreases from the top wall 23 toward the surface 3a of the padless portion 3. Further, the inclination angle θ of the portions 22a and 22b with respect to the surface 3a of the paddle portion 3 gradually decreases from the inner side to the outer side in the tire radial direction. For example, the inclination angle θ of the portions 22a and 22b in the vicinity of the inner end of the protrusion 21 in the tire radial direction is sufficiently smaller than the inclination angle θ of the portions 22a and 22b in the vicinity of the outer end of the protrusion 21 in the tire radial direction. The inclination angle θ can be set to, for example, 10 degrees or more and 90 degrees or less.

  Similar to the first to third embodiments, in this embodiment, the damage resistance of the protrusions 21 can be improved by reducing the volume of the protrusions 21 by the inclination of the top wall 23 in the tire radial direction (arrow Sr).

  Even if the rotation direction of the pneumatic tire 1 is either the direction of the arrow R or the opposite direction, the portions 22a and 22b inclined in the tire circumferential direction are on the kicking side. The movement can be suppressed and the damage resistance of the protrusion 21 can be improved.

  The external force applied by the protrusion 21 when kicking out tends to be greater on the outer side than on the inner side in the tire radial direction. Therefore, it is more effective by setting the inclination angle θ in the tire circumferential direction of the portions 22a and 22b gradually smaller from the inner side to the outer side in the tire radial direction, that is, by setting the portions 22a and 22b relatively small. Thus, the movement of the protrusion 21 at the time of kicking can be suppressed, and the trauma resistance on the kicking side can be improved.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 2a Tread end 3 Padless part 3a Surface 4 Side wall part 5 Bead part 5a Innermost end 6 Bead core 7 Bead filler 8 Carcass ply 9 Inner liner 10 Belt layer 11A, 11B Block 11a, 11b part 11c Edge 21 Protrusion 22 Side wall 22a, 22b, 22c Portion 23 Top wall 24 Edge WT Tire height H Protrusion height Sr Tire radial direction inclination Sc Tire circumferential direction inclination R Rotation direction θ Inclination angle

Claims (9)

Provided with protrusions provided on the paddle part,
The protrusion is
A side wall protruding from the surface of the buttress part;
A top wall provided at the tip of the side wall,
The pneumatic tire, wherein the top wall is inclined in the tire radial direction so that a protrusion height, which is a distance from the surface of the buttress portion, decreases from the outer side to the inner side in the tire radial direction.   The pneumatic tire according to claim 1, wherein each of the pair of portions facing the tire circumferential direction of the side wall has a triangular shape.   The pneumatic tire according to claim 2, wherein the pair of portions of the side walls facing each other in the tire circumferential direction are triangles having the same shape and dimensions.   The pneumatic tire according to claim 2, wherein one of the triangular areas of the pair of side walls facing the tire circumferential direction has a smaller area than the other triangular area.   The pneumatic shape according to claim 4, wherein among the pair of portions of the side wall facing the tire circumferential direction, the triangular shape of one portion has the same bottom length as the triangular shape of the other portion and a low height. tire.   5. The pneumatic tire according to claim 4, wherein the triangular shape of one portion of the pair of portions facing the tire circumferential direction of the side wall is similar to the triangular shape of the other portion and has a small size.   The outer end and the inner end of the protrusion in the tire radial direction are provided in a range of 0.1 to 1.0 times the tire height from the innermost end of the pneumatic tire. The pneumatic tire according to any one of items 6. A block extending from the tread portion to the buttress portion beyond the tread end,
The pneumatic tire according to any one of claims 1 to 7, wherein the protrusion is arranged such that the outer end is adjacent to an inner end of the block in the tire radial direction. The block is
A first block in which an edge constituted by a portion extending in the tire width direction and a portion extending in the tire radial direction is located at a first position;
A second block in which an edge constituted by a portion extending in the tire width direction and a portion extending in the tire radial direction is located at a second position on the center side in the tire width direction from the first position;
The pneumatic tire according to claim 8, wherein the first block and the second block are alternately arranged in a tire circumferential direction.

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