JP2013018446A - Tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire that can surely improve a heat radiation of a tread part while controlling the decrease in rigidity and wear resistance of the tread part.SOLUTION: The tire 1 includes a buttress 14 that extends from a tread end 13e outside of a tread width direction twd in the tread part 13 toward inside of the tire radial direction trd and ranges to a sidewall part 12. In the lateral groove 40A to contact the buttress 14, a protrusion 200 that projects from a groove bottom 40Ab of the lateral groove 40A toward outside of tire radial direction trd is formed, and an outer end 200a of the projection 200 in the tread width direction twd is located outside of the tread width direction twd than the land part 100 that composes the buttress 14.

Description

  The present invention relates to a tire mounted on a vehicle, and more particularly to a tire capable of improving the heat dissipation of the tire.

  Since the rubber material having viscoelasticity follows hysteresis behavior, the tread portion of the tire generates heat by repeating deformation and contraction due to rolling. When the rubber material constituting the tread portion increases, hysteresis loss due to bending deformation or shear deformation during tire rolling increases. Therefore, the temperature of a tire having a relatively thick tread portion is likely to increase.

  In particular, large tires used in large vehicles used in mines and construction sites not only have a large amount of rubber material used, but also under heavy load conditions, poor road surfaces, and severe traction conditions. Since the tire is repeatedly deformed and contracted, it has a feature that it easily generates heat. If the tire becomes hot during running, it may cause separation (separation) between the rubber material forming the tread portion and the belt layer, leading to a faster tire replacement cycle.

  Therefore, conventionally, by forming a sub-groove along the width direction of the tread portion (hereinafter referred to as the tread width direction) in the tread portion, the amount of the rubber material as a heat source is reduced and the surface area of the tread portion is increased. Therefore, a method for promoting heat dissipation of the tread portion is known (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-205706 FIG.

  However, the conventional tire has the following problems. That is, by forming a lateral groove portion (sub-groove) that intersects the tire circumferential direction and increasing the groove area, heat dissipation can be promoted, but an increase in the groove area leads to a decrease in rigidity and wear resistance of the tread portion. . Thus, since the heat dissipation of the tire and the rigidity of the tire are in a trade-off relationship, there is a limit to securing the heat dissipation by increasing the groove area.

  Then, an object of this invention is to provide the tire which can improve the heat dissipation of a tread part reliably, suppressing the fall of the rigidity and abrasion resistance of a tread part.

  In order to solve the above-described problems, a tire (pneumatic tire 1) as an exemplary aspect of the present invention includes a bead portion (bead portion 11) and a sidewall portion (sidewall portion 12) connected to the bead portion. A tread portion (tread portion 13) that contacts the road surface, and the tread portion includes a plurality of lateral groove portions (lateral grooves 40A, 40B, 40C) intersecting the tire circumferential direction (tcd), A land portion (land portion block 100) partitioned by a lateral groove portion, from a tread end portion located on the outer side in the tread width direction of the tread portion to a groove bottom of the lateral groove portion toward the inner side in the tire radial direction. An extending buttress portion (buttress portion 14) is provided, and the lateral groove portion in contact with the buttress portion is directed outward from the groove bottom (groove bottom 40Ab) of the lateral groove portion in the tire radial direction (tire radial direction trd). And a projecting portion (projecting portion 200) projecting outward from the groove bottom of the lateral groove portion in the tread width direction is formed, and an outer end portion (width direction outer side surface 200a) in the tread width direction of the projecting portion is formed. Is located on the outer side in the tread width direction than the land portion constituting the buttress portion.

  Since the tire according to the present invention is provided with a protruding portion that protrudes outward in the tread width direction from the land portion constituting the buttress portion, the air passing through the buttress portion of the tire hits the protruding portion and the flow is disturbed. Is done. The projecting portion is provided in a lateral groove portion parallel to the tread width direction, and air disturbed by hitting the projecting portion easily flows into the lateral groove portion. On the other hand, the air in the lateral groove portion easily flows out of the tire through the protruding portion. That is, the protrusion is located in the lateral groove formed between the land portions, so that the air flow around the tire is disturbed by the protrusion, so that the air can be easily taken into the lateral groove, or the air in the lateral groove is Or expelling discharge. Thus, by increasing the flow rate of the air passing through the horizontal groove portion, the heat transfer coefficient inside the horizontal groove portion can be improved. Therefore, the temperature of the tread can be lowered and the heat dissipation can be improved.

  Further, the tire according to the present invention may be configured to satisfy Lw / Lr> 1, where Lw is the length of the protruding portion in the tread width direction and Lr is the length of the protruding portion in the tire circumferential direction. .

  In addition, the tire according to the present invention satisfies 0 <Lh <H, where H is the length in the tire radial direction of the land portion adjacent to the lateral groove and Lh is the length of the protruding portion in the tire radial direction. You may comprise.

  Further, in the tire according to the present invention, the protruding portion center line Lm along the longitudinal direction of the protruding portion set at the central portion in the tire circumferential direction of the protruding portion is in the tread width direction line along the tread width direction. You may comprise so that it may incline.

  The tire according to the present invention may be configured such that the projecting portion center line coincides with the center line of the lateral groove portion along the extending direction of the lateral groove portion.

  The tire according to the present invention may be configured to satisfy Lr <0.5 × WA, where WA is the length of the lateral groove portion in the tire circumferential direction and Lr is the length of the protruding portion in the tire circumferential direction. .

  In the tire according to the present invention, circumferential groove portions (circumferential grooves 20A and 20B) along the tire circumferential direction may be formed, and the lateral groove portions may be communicated with the circumferential groove portion.

  The tire according to the present invention includes the protruding portion formed in the lateral groove portion, thereby increasing the flow rate of air flowing in the lateral groove portion formed in the tread portion and improving the heat dissipation of the tread portion. Further, the tire according to the present invention has improved heat dissipation by providing a protruding portion in the lateral groove portion, and does not increase the groove area of the tread portion, thereby suppressing a decrease in rigidity and wear resistance of the tread portion. It is possible to improve heat dissipation.

It is a perspective view of the pneumatic tire concerning this embodiment. It is sectional drawing of the tread width direction and tire radial direction of the pneumatic tire which concerns on this embodiment. It is the expansion perspective view which expanded the tread part of the pneumatic tire. It is the side view seen from the arrow A direction of FIG. FIG. 4 is a plan view seen from the direction of arrow B in FIG. 3, and is a schematic diagram illustrating the air flow that occurs when the pneumatic tire 1 rotates in the rotation direction R. It is the top view which visually recognized the pneumatic tire concerning a modification from the field perpendicular to the tread part. Fig.6 (a) is a schematic diagram explaining the flow of the air produced when the pneumatic tire 2 rotates in the rotation direction R1, and FIG.6 (b) rotates the pneumatic tire 2 in the rotation direction R2. It is a schematic diagram explaining the flow of the air which arises sometimes. It is a figure explaining the shape of the protrusion concerning a modification.

  An embodiment of a pneumatic tire 1 as a tire according to the present invention will be described with reference to the drawings. Specifically, (1) the configuration of the pneumatic tire, (2) the description of the protruding portion, (3) the action / effect, and (4) the modification will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions 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 is contained.

(1) Configuration of Pneumatic Tire FIG. 1 is a perspective view of a pneumatic tire 1 according to this embodiment. FIG. 2 is a cross-sectional view of the pneumatic tire 1 along the tread width direction twd and the tire radial direction trd.

  The pneumatic tire 1 is located between a bead portion 11 that contacts the rim, a sidewall portion 12 that constitutes a side surface of the tire, a tread portion 13 that contacts the road surface, and the sidewall portion 12 and the tread portion 13. And a buttress portion 14.

  The buttress part 14 is located on an extension of the sidewall part 12 in the tire radial direction trd, and is a part where the side surfaces of the tread part 13 are continuous. The buttress portion 14 extends from the tread end portion 13e outside the tread width direction twd of the tread portion 13 toward the inside in the tire radial direction trd. The buttress portion 14 is a portion that does not come into contact with the ground during normal running. The buttress portion is a region extending from the tread end portion on the outer side in the width direction of the tread portion to the groove bottom of the lateral groove portion toward the inner side in the tire radial direction.

  In the tread portion 13, circumferential grooves 20A and 20B are formed along the tire circumferential direction tcd. The tread portion 13 is formed with circumferential land portions 30A, 30B, 30C partitioned by the circumferential grooves 20A, 20B.

  A transverse groove 40A that intersects the tire circumferential direction is formed in the circumferential land portion 30A. A transverse groove 40B that intersects with the tire circumferential direction is formed in the circumferential land portion 30B. A transverse groove 40C that intersects with the tire circumferential direction is formed in the circumferential land portion 30C. In the present embodiment, land blocks 100, 110, and 120 are formed in the circumferential land portions 30A, 30B, and 30C by being divided by the lateral grooves 40A, 40B, and 40C. The lateral grooves 40A, 40B, and 40C extend along the tread width direction twd and communicate with the circumferential grooves 20A and 20B.

  The pneumatic tire 1 has a carcass layer 51 that is a skeleton of the pneumatic tire 1. An inner liner 52 that is a highly airtight rubber layer corresponding to a tube is provided inside the carcass layer 51 in the tire radial direction. Both ends of the carcass layer 51 are supported by a pair of beads 53.

  A belt layer 54 is disposed outside the carcass layer 51 in the tire radial direction. The belt layer 54 includes a first belt layer 54a and a second belt layer 54b on which steel cords are arranged. The steel cord is disposed with a predetermined angle with respect to the tire equator line CL. The tread portion 13 is disposed on the outer side in the tire radial direction of the belt layer 54 (the first belt layer 54a and the second belt layer 54b).

  FIG. 3 is an enlarged perspective view in which the tread portion 13 of the pneumatic tire 1 is enlarged. 4 is a side view seen from the direction of arrow A in FIG. The lateral grooves 40A and 40C that are in contact with the buttress portion 14 of the pneumatic tire 1 protrude outward from the groove bottom 40Ab in the tire radial direction trd and from the lateral grooves 40A and 40C toward the outer side in the tire radial direction trd in the tread width direction twd. A protruding portion 200 that protrudes is formed.

  The pneumatic tire 1 may be filled with an inert gas such as nitrogen gas instead of air. In the present embodiment, the pneumatic tire 1 is, for example, a radial tire having a flatness ratio of 80% or less, a rim diameter of 57 "or more, a load load capacity of 60 mton or more, and a load coefficient (k-factor) of 1.7 or more. .

(2) Description of Protrusion The protrusion 200 is located on the outer side in the tire radial direction trd of the line BL connecting the groove bottoms 40Ab of the lateral grooves 40A and connects the groove bottoms 40Ab of the horizontal grooves 40A in the tread width direction twd. Is arranged so as to extend in the tread width direction across the cross section (see FIG. 3). The width direction outer side surface 200a as the outer end portion in the tread width direction twd of the protruding portion 200 is located on the outer side of the tread width direction twd than the side surface 101 of the land portion block 100 constituting the buttress portion 14.

(3) Action / Effect In the pneumatic tire 1 according to the present embodiment, since the protruding portions 200 are formed in the lateral grooves 40A and 40C that are in contact with the buttress portion 14, the air passing through the surface of the pneumatic tire 1 is prevented. It can be disturbed by the protrusion 200 and can be easily taken into the lateral groove 40 formed in the land block 100.

  FIG. 5 is a plan view seen from the direction of arrow B in FIG. 3, and is a schematic diagram for explaining the air flow generated when the pneumatic tire 1 rotates in the rotation direction R.

  As shown in FIG. 5, when the pneumatic tire 1 rotates in the rotation direction R, the air flow (relative wind) AR caused by the rotation hits the side surface 200b of the protruding portion 200 and flows along the side surface 200b. Then, it is taken into the lateral groove 40A (AR1 shown) or flows over the protruding portion 200 (AR2 shown). In addition, on the rear side in the rotation direction of the side surface 200b of the protruding portion 200, an air flow toward the outer side in the tread width direction is created, and air is sucked out through the lateral groove 40A and the circumferential groove 20A, and then outward from the lateral groove 40A. An incoming air flow AR3 occurs.

  Further, in the region S located on the inner side in the tread width direction of the protruding portion 200 in the lateral groove 40A, when the air flow AR1 flowing into the lateral groove 40A is larger than the air flow AR3 flowing out from the lateral groove 40A, the tread An air flow toward the inside in the width direction is generated. On the other hand, when the air flow AR3 flowing out from the horizontal groove 40A is larger than the air flow AR1 flowing into the horizontal groove 40A, an air flow toward the outer side in the tread width direction is generated.

  Thus, by providing the protrusion 200, it is possible to increase the flow rate of air passing through the horizontal groove A by allowing air to flow into the horizontal groove 40A or out of the horizontal groove. Thereby, the heat transfer coefficient inside the lateral groove 40A is improved, and the temperature rise of the land block 100 can be reduced. Furthermore, the temperature rise of the tread portion 13 can be reduced.

  Further, when the pneumatic tire 1 rotates in the rotation direction R, the air flow (relative wind) AR caused by the rotation hits the side surface 200b of the protrusion 200 and flows over the protrusion 200. Thereby, the heat transfer coefficient inside the lateral groove 40A can be improved, and the temperature of the land block 100 can be reduced. Furthermore, the temperature of the tread portion 13 can be reduced.

  The protrusion 200 is configured to satisfy Lw / Lr> 1, where Lw is the length of the protrusion 200 in the tread width direction twd and Lr is the length of the protrusion 200 in the tire circumferential direction tcd. . For example, if the circumferential length is too long with respect to the tread width direction length of the protrusion, the effect of generating the air flow AR in the rotational direction R of the pneumatic tire 1 is diminished, and the lateral groove opening to the buttress portion is reduced. Since the area is reduced, there is a possibility that a sufficient flow rate of air flowing into the lateral groove cannot be obtained. However, by configuring the protrusions so as to satisfy Lw / Lr> 1, it is possible to efficiently generate an air flow accompanying the rotation of the pneumatic tire and to easily guide the air into the lateral groove.

  Furthermore, the protrusion 200 is configured to satisfy 0 <Lh <H, where H is the length in the tire radial direction of the land portion adjacent to the lateral groove and Lh is the length of the protrusion in the tire radial direction. ing. In addition, the protrusion is configured to satisfy Lr <0.5 × WA, where WA is the length of the lateral groove in the tire circumferential direction and Lr is the length of the protrusion in the tire circumferential direction. By configuring the protrusions in this way, it is possible to secure the opening area of the lateral groove part in the buttress part, and preventing the flow of air from the outside of the tire into the lateral groove by providing the protrusion part is prevented. Can do.

(4) Modified Example (4-1) Block Shape FIG. 6 is a plan view of a pneumatic tire 2 shown as a modified example of the present embodiment as seen from a direction perpendicular to the tread portion. In the pneumatic tire 2, the center line Ln of the lateral groove 41A along the extending direction of the lateral groove 41A formed in the circumferential land portions 30A, 30B, 30C is an angle with respect to the tread width direction line TL along the tread width direction twd. θ is inclined. Further, in the protruding portion 201, the protruding portion center line Lm along the longitudinal direction of the protruding portion 201 set at the center portion M in the tire circumferential direction tcd is inclined with respect to the tread width direction line TL. Furthermore, the protrusion center line Lm of the protrusion 201 coincides with the center line Ln of the lateral groove 41A.

  Fig.6 (a) is a schematic diagram explaining the flow of the air produced when the pneumatic tire 2 rotates in the rotation direction R1, and FIG.6 (b) rotates the pneumatic tire 2 in the rotation direction R2. It is a schematic diagram explaining the flow of the air which arises sometimes.

  As shown in FIG. 6A, when the pneumatic tire 2 rotates in the rotation direction R1, the air flow (relative wind) AR caused by the rotation is located on the front side of the rotation direction R1 of the protrusion 201. It strikes the side surface 201b and is taken into the lateral groove 41A. Since the lateral groove 41A is inclined, the air flow AR is easily taken into the lateral groove 41A.

  Further, as shown in FIG. 6B, when the pneumatic tire 1 rotates in the rotation direction R2, the air flow (relative wind) AR caused by the rotation hits the side surface 201a of the protrusion 201, and the protrusion It flows over 201. At this time, an air flow toward the outer side in the tread width direction is generated on the rear side in the rotation direction of the side surface 201b of the protrusion 201. By this flow, air is sucked out through the lateral groove 41A, and an air flow AR is generated from the lateral groove 41A to the outside. Further, since the lateral groove 41A is inclined, air easily flows from the lateral groove 41A to the outside. Thereby, the heat transfer rate inside the lateral groove 41A is improved, and the effect of reducing the temperature of the land block 300 can be enhanced.

(4-2) Shape of the protruding portion In the embodiment described above, the shape of the protruding portion has been described as a rectangular shape. However, the protrusion can be modified as described below. FIGS. 7A to 7I show modified examples of the shape of the protruding portion, and are plan views viewed from a direction perpendicular to the tread portion. FIGS. 7A to 7F show modifications of the protrusions in the embodiment in which the center line of the lateral groove is parallel to the tread width direction line, and FIGS. 7G to 7I show the lateral groove 40A. It is a modification of the protrusion part in embodiment in which the centerline inclined with respect to the tread width direction line.

  The protrusion 202 shown in FIG. 7A is formed to be tapered toward the inner side in the tread width direction twd, and has a triangular shape in a plane. FIG. 7B is formed to be tapered toward the outer side in the tread width direction twd, and has a triangular shape in a plane. The protrusion 204 shown in FIG. 7C has a shape similar to the protrusion 202 shown in FIG. 7A, and is formed so as to taper inward in the tread width direction. The end of the projecting portion 204 inside the tread width direction twd is not pointed and has a trapezoidal shape in a plane. The protrusion 205 shown in FIG. 7 (d) has a shape similar to the protrusion 203 shown in FIG. 7 (b), and is formed to taper outward in the tread width direction twd. The end of the protrusion 205 on the outer side in the tread width direction is not pointed and has a trapezoidal shape in a plane. The protrusion 206 shown in FIG. 7 (e) is formed so as to taper inward in the tread width direction twd, and the wall surface extending in the tread width direction twd is recessed toward the center side in the tire circumferential direction tcd. Yes. According to such a configuration, it is possible to increase the flow rate of the air passing through the groove 40A. Further, the protruding portion 207 shown in FIG. 7 (f) is formed to be tapered toward the outer side of the tread width direction twd, and the wall surface extending in the tread width direction twd is directed toward the center side in the tire circumferential direction tcd. It is recessed.

  Moreover, the protrusion part 208 shown to FIG. 7G is an ellipse shape in a plane, and the longitudinal direction extended in the tread width direction is along the longitudinal direction of 40 A of horizontal grooves. Thus, it becomes possible to reduce the resistance with respect to the flow of air by making the wall surface which comprises the protrusion part 208 into a curvilinear shape. Moreover, the protrusion part 209 shown in FIG.7 (h) is a rhombus shape in a plane. The thickness of the protruding portion 209 in the tire circumferential direction tcd is configured to be the thickest on the side surface 101 of the land portion block 100 that constitutes the buttress portion 14, and is tapered from the portion toward the inner side and the outer side in the tread width direction. Is formed.

  Although the contents of the present invention have been disclosed through the embodiments of the present invention as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments and examples will be apparent to those skilled in the art. For example, the embodiment of the present invention can be modified as follows.

  When the pneumatic tire according to the present embodiment is applied to a so-called extra-large tire, a remarkable effect can be obtained, but it can also be applied to a general-purpose tire. By forming a protrusion that protrudes in the tread width direction on the buttress part, the heat transfer rate of the pneumatic tire can be improved, and the temperature of the tread surface can be increased in situations where the tread is likely to generate heat, such as high-speed driving and rough road driving. The rise can be reduced.

  As a typical example, the tread pattern of the pneumatic tire 1 shown in FIG. 1 is illustrated. However, it is not limited to this tread pattern. For example, the type which has the rib-like land part in which the horizontal groove is not formed in the tire equator line vicinity of the pneumatic tire 1 may be sufficient.

  In the embodiment described above, it has been described that the lateral groove portions (the lateral grooves 40 and the lateral grooves 41A) are all formed at the same angle with respect to the tire circumferential direction. However, in the same pneumatic tire, the angle of the lateral groove portion with respect to the tire circumferential direction is not necessarily the same. For example, the circumferential land portions 30A, 30B, and 30C may be formed at different angles. Furthermore, transverse grooves having different angles may also be formed in one circumferential land portion 30A.

  Further, in the above-described embodiment, the center of the protruding portion in the tire circumferential direction is configured to overlap the center of the lateral groove in the tire circumferential direction, but is not limited to this configuration, and the lateral groove portion is sandwiched in the tire circumferential direction. You may arrange | position a protrusion part so that it may become close to either one among the land part blocks arrange | positioned.

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

  DESCRIPTION OF SYMBOLS 1, 2, 3 ... Pneumatic tire, 11 ... Bead part, 12 ... Side wall part, 13 ... Tread part, 13e ... Tread edge part, 14 ... Buttress part, 20A, 20B ... Circumferential groove | channel, 30A, 30B, 30C ... circumferential land, 40A, 40B, 40C ... transverse groove, 40Ab ... groove bottom, 41A ... transverse groove, 41Aa ... wall surface, 51 ... carcass layer, 52 ... inner liner, 53 ... bead, 54 ... belt layer, 54a ... first Belt layer 54b second belt layer 100, 110, 120 land block 101 101 side surface 200 projecting portion 200a lateral side surface 200b side surface 201 projecting portion 201b side surface 202 203, 204, 205, 206, 207, 208, 209 ... projection, 300 ... land block, θ ... angle, CL ... Ear equator line, H: Length of side surface of land portion in tire radial direction, Lh: Length of projecting portion in tire radial direction, Lm: Center length of projecting portion, ln: Center line of lateral groove along lateral groove extending direction Lr: length of the protruding portion in the tire circumferential direction, Lw: length of the protruding portion in the tread width direction M: central portion of the protruding portion in the tire circumferential direction, R1, R2: rotational direction, TL: tread width direction line, In: center line, trd: tire radial direction, twd: tread width direction, tcd: tire circumferential direction, WA: length of lateral groove in tire circumferential direction

Claims (7)

A bead part;
A sidewall portion connected to the bead portion;
A tread that contacts the road surface,
A tire having
The tread portion is formed with a plurality of lateral groove portions that intersect the tire circumferential direction, and a land portion that is partitioned by the lateral groove portions,
A buttress portion extending from the tread end located on the outer side in the tread width direction of the tread portion to the groove bottom of the lateral groove portion toward the inner side in the tire radial direction,
The lateral groove portion in contact with the buttress portion is formed with a protruding portion that protrudes outward in the tire radial direction from the groove bottom of the horizontal groove portion and protrudes outward in the tread width direction from the lateral groove portion,
An outer end portion of the protruding portion in the tread width direction is a tire positioned on an outer side in the tread width direction than the land portion constituting the buttress portion.   The tire according to claim 1, wherein Lw / Lr> 1 is satisfied, where Lw is a length in the tread width direction of the protrusion and Lr is a length in the tire circumferential direction of the protrusion.   The length of the land portion adjacent to the lateral groove portion in the tire radial direction is H, and the length of the protruding portion in the tire radial direction is Lh, and 0 <Lh <H is satisfied. Tire described in.   The protrusion center line along the longitudinal direction of the protrusion set in the center of the protrusion in the tire circumferential direction is inclined with respect to the tread width direction line along the tread width direction. The tire according to any one of claims 1 to 3.   The tire according to claim 4, wherein the projecting portion center line coincides with a center line of a lateral groove portion along a direction in which the lateral groove portion extends.   The length of the said circumferential groove part of the tire circumferential direction is set to WA, and the length of the protrusion part of the tire circumferential direction is set to Lr, Lr <0.5xWA is satisfy | filled. The described tire. The tread portion is further formed with a circumferential groove along the tire circumferential direction,
The tire according to any one of claims 1 to 6, wherein the lateral groove portion communicates with the circumferential groove portion.

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