JP2010167832A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of further reducing the temperature in a tire side part, by regulating a shape of a second fin extending in the tire peripheral direction among a turbulent flow generating fin. <P>SOLUTION: This pneumatic tire 1 is provided by arranging the turbulent flow generating fin 10 projecting in the tire width direction in the tire side part 8 arranged on a side surface of the tire. The turbulent flow generating fin 10 is composed of a first fin 11 extended in the tire radial direction and arranged in a plurality at a predetermined interval in the tire peripheral direction, and a second fin 12 arranged between the mutual first fins 11 and 11 adjacent in the tire peripheral direction and extended in the tire peripheral direction. The second fin 12 is set lower than a height in an end part of the tire peripheral direction in a height in an intermediate part in the tire peripheral direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire capable of reducing the temperature of a tire side portion that easily deteriorates.

  In a pneumatic tire, when the temperature rises, it is not preferable from the viewpoint of durability because it promotes a change with time, that is, a change in physical properties of the material, or causes damage to the tread when traveling at a high speed. To improve durability, especially in off-the-road radial (ORR) tires, truck bus radial (TBR) tires used in heavy loads, and run-flat tires during puncture travel (running at an internal pressure of 0 kPa) Reducing the tire temperature is a major issue. For example, in a run-flat tire with a reinforcing rubber with a crescent-shaped cross section, radial deformation concentrates on the reinforcing rubber during puncture and this part reaches a very high temperature, which has a great impact on durability. .

  Conventionally, as a technique for promoting heat dissipation of a pneumatic tire, it is known that a plurality of fins protruding in the tire width direction are provided on the side portion of the tire body, and air turbulence is generated near the fins when the tire rotates ( For example, see Patent Document 1). As shown in FIG. 18 in Patent Document 1, a plurality of first fins that extend in the tire radial direction and that are provided at predetermined intervals in the tire circumferential direction are provided between a pair of adjacent first fins. Further, a turbulent flow generating fin comprising the second fin is disclosed.

WO200703405 (see FIG. 18)

  Here, in recent years, since further temperature reduction of the tire side portion has been demanded, it is necessary to devise the shape and size of the turbulent flow generating fin. The shape and size of the fin are not specified.

  An object of the present invention is to provide a pneumatic tire capable of further reducing the temperature of the tire side portion by defining the shape of the second fin extending in the tire circumferential direction among the turbulent flow generating fins. It is in.

  The first feature of the present invention is that a turbulent flow generating fin (turbulent flow generating fins 10, 110, 210, and so on) protruding in the tire width direction on a tire side portion (tire side portion 8) disposed on a side surface of the tire. 310), the turbulent flow generating fins extending in the tire radial direction, and a plurality of first fins (first fins) provided at predetermined intervals in the tire circumferential direction. 11, 111, 211, 311) and second fins (second fins 12, 112, 122, 212, 312) provided between the first fins adjacent in the tire circumferential direction and extending in the tire circumferential direction. The second fin is characterized in that the height (height hc) at the intermediate portion in the tire circumferential direction is set lower than the end portion (Hc) in the tire circumferential direction.

  Therefore, the temperature reduction effect of the tire side portion during vehicle traveling is further enhanced. This will be specifically described below.

  When the pneumatic tire rotates, the air flow generated by the rotation gets over the first fins and becomes a turbulent flow, and hits the tire side portion in the region between the first fins, so this region becomes the temperature reduction region. Furthermore, since the turbulent flow over the first fin flows toward the outer side in the tire radial direction by the traveling wind accompanying traveling of the vehicle, cooling by heat exchange is promoted.

  Here, when the second fin is formed at the same height at an arbitrary portion in the tire circumferential direction, the air flow that flows over the first fin and toward the outer side in the tire radial direction is upstream of the second fin ( As a result of the air flow stagnation region that stagnates on the inner side in the tire radial direction) being formed in a wide range, the flow rate of the air flow over the second fin is reduced.

  Therefore, as in the present invention, the height of the intermediate portion in the tire circumferential direction is set to be lower than the height of both end portions in the tire circumferential direction, so that the second fin is overcome and directed outward in the tire radial direction. Therefore, the air flow stagnation region becomes very small, the heat exchange efficiency is improved, and the temperature reduction region is expanded.

  In other features, the second fins (second fins 112 and 122) are divided into a plurality of divided bodies (divided bodies 113, 114, 123, and 124) separated from each other along the tire circumferential direction. The gist is that it is arranged.

  In other features, the divided bodies (divided bodies 123 and 124) constituting the second fin (second fin 122) have an intermediate height (hc) in the tire circumferential direction at the end side in the tire circumferential direction ( The gist is that it is set lower than Hc).

  In other features, the divided bodies (213, 214, 215, 313, 314, 315) constituting the second fin (second fins 212, 312) are divided into three or more along the tire circumferential direction. The height (hc) of the divided body (divided bodies 215, 315) arranged on the intermediate side in the tire circumferential direction is set lower than the divided bodies (213, 214, 313, 314) on the end side in the tire circumferential direction. It is a summary.

  In other features, the divided body constituting the second fin (second fin 312) is a divided body (divided body 315) disposed on the intermediate side in the tire circumferential direction, and is a divided body on the end side in the tire circumferential direction. The gist is that it is arranged on the outer side in the tire radial direction from (divided bodies 313, 314).

  In another feature, a predetermined gap (gap) is provided between the first fin (first fin 11, 111, 211, 311) and the second fin (second fin 12, 112, 122, 212, 312). 15 and 115) are provided.

  According to the present invention, it is possible to obtain a pneumatic tire in which the temperature reduction effect of the tire side portion during traveling of the vehicle is further enhanced by the turbulent flow generation fin.

1 is a side view of a pneumatic tire according to a first embodiment of the present invention. 1 is a perspective view showing a cross section of a main part of a pneumatic tire according to a first embodiment of the present invention. FIG. 3 is a perspective view of the turbulent flow generation fin of FIG. 2 viewed from the inside in the tire radial direction. It is the perspective view which looked at the modification of the fin for turbulent flow generation by the 1st Embodiment of this invention from the tire radial inside. It is a top view which shows the inclination angle of the 1st fin of the fin for turbulent flow generation by the 1st Embodiment of this invention. It is a top view which shows the inclination angle of the 2nd fin of the fin for turbulent flow generation by the 1st Embodiment of this invention. It is sectional drawing which shows roughly the state which a turbulent flow generate | occur | produces with a 1st fin. It is a top view which shows roughly the state which a turbulent flow generate | occur | produces with the 2nd fin of a comparative example. It is a top view which shows roughly the state which a turbulent flow generate | occur | produces with the 2nd fin of the 1st Embodiment of this invention. It is a perspective view which shows the principal part cross section of the pneumatic tire by the 2nd Embodiment of this invention. It is the perspective view which looked at the fin for turbulent flow generation of FIG. 10 from the tire radial inside. It is the perspective view which looked at the modification of the fin for turbulent flow generation by the 2nd Embodiment of this invention from the tire radial inside. It is a perspective view which shows the principal part cross section of the pneumatic tire by the 3rd Embodiment of this invention. It is the perspective view which looked at the fin for turbulent flow of FIG. 13 from the tire radial inside. It is a perspective view which shows the principal part cross section of the pneumatic tire by the 4th Embodiment of this invention. It is the perspective view which looked at the fin for turbulent flow generation of FIG. 15 from the tire radial inside. It is a perspective view which shows the principal part cross section of the pneumatic tire which concerns on the prior art example in an Example. It is a perspective view which shows the principal part cross section of the pneumatic tire which concerns on the comparative example 1 in an Example. It is the perspective view which looked at the fin for turbulent flow generation of FIG. 18 from the tire radial inside. It is a perspective view which shows the principal part cross section of the pneumatic tire which concerns on the comparative example 2 in an Example. It is the perspective view which looked at the fin for turbulent flow generation of FIG. 20 from the tire radial inside.

  Hereinafter, details of a pneumatic tire according to an embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic, and the thicknesses and ratios of the material layers are different from actual ones. Therefore, specific thicknesses and dimensions 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.

[First embodiment]
First, the turbulent flow generating fin according to the first embodiment of the present invention will be described.

<Schematic configuration of pneumatic tire>
FIG. 1 is a side view of a pneumatic tire according to a first embodiment of the present invention, and FIG. 2 is a perspective view showing a cross-section of a main part of the pneumatic tire according to the first embodiment of the present invention.

  As shown in FIGS. 1 and 2, a pneumatic tire 1 is a tire that is assembled to a construction vehicle as an example, and a pair of annular bead cores 2 and 2 that are spaced apart in the tire width direction, and these The carcass 3 that connects the bead cores 2 and 2 in a crown shape and serves as a skeleton of the tire, the tread core 4 and the belt layer 5 disposed on the top of the carcass 3, and the tread 6 provided on the top of the carcass 3 And a shoulder portion 7 formed on both sides of the tread portion 6 in the tire width direction, and a tire side portion 8 constituting a tire side surface. For example, a steel cord is used for the bead core 2 to form a bead portion 9. The tire side portion 8 is provided with a turbulent flow generating fin 10 which will be described later.

<Configuration of turbulent flow generation fin>
3 is a perspective view of the turbulent flow generating fin of FIG. 2 as viewed from the inside in the tire radial direction, and FIG. 4 is a modified example of the turbulent flow generating fin according to the first embodiment of the present invention as viewed from the inside of the tire radial direction. FIG. 5 is a plan view showing an inclination angle of the first fin of the turbulent flow generating fin according to the first embodiment of the present invention, and FIG. 6 is a turbulent flow generating one according to the first embodiment of the present invention. It is a top view which shows the inclination | tilt angle of the 2nd fin of a fin.

  As shown in FIGS. 2 and 3, the tire side portion 8 is provided with turbulent flow generating fins 10 that protrude outward in the tire width direction. The turbulent flow generating fin 10 is provided between a first fin 11 extending in the tire radial direction from the vicinity of the bead core 2 to the shoulder portion 7 and a pair of first fins 11 and 11 adjacent to each other in the tire circumferential direction. It is comprised from the 2nd fin 12 extended along the circumferential direction. The first fin 11 shown in FIG. 3 is originally curved along the side surface of the tire side portion 8 as shown in FIG. 2, but is drawn in a straight line for easy understanding.

  The height Hr of the first fin 11 is set to be a constant height at any part in the tire radial direction, and the thickness of the first fin 11 is set to W. Further, the distance between the ends on the inner side in the tire radial direction of the pair of first fins 11 and 11 adjacent in the tire circumferential direction is set to P.

  About the said 2nd fin 12, the height hc in the intermediate part 13 of a tire circumferential direction is set lower than the height Hc in the both ends 14 of a tire circumferential direction. Specifically, the ratio hc / Hc between the height Hc and hc is preferably set to 0.5 or less. The height Hr of the first fin 11 is preferably 3 mm ≦ Hr ≦ 20 mm, and the height Hc of the second fin 12 is preferably 3 mm ≦ Hc ≦ 20 mm. Furthermore, since the length along the tire circumferential direction of the second fin 12 is set to be shorter than the distance between the adjacent first fins 11, 11, the left and right ends of the second fin 12, the first fin 11, A predetermined gap 15 is provided between them. The relationship among Hr, Hc, P, and W described above is preferably 1 ≦ P / Hr ≦ 20, 1 ≦ P / Hc ≦ 20, and 1 ≦ (P−W) / W ≦ 100.

  Further, as shown in FIG. 4, a plurality of grooves 17 may be arranged on the upper surface of the first fin 16 at substantially equal intervals along the tire radial direction. When the pneumatic tire 1 rotates, the effect of cooling the tire side portion 8 by air flowing in from these grooves 17 is increased.

  Further, as shown in FIG. 5, the first fins 11 constituting the turbulent flow generation fin 10 extend in a direction inclined by an angle θ1 with respect to the tire radial direction. On the other hand, as shown in FIG. 6, the second fin 12 extends along the tire circumferential direction, and specifically extends in a direction inclined by an angle θ2 with respect to the tire radial direction. The angle θ1 described above is preferably −30 ° ≦ θ1 ≦ 30 °, and the angle θ2 is preferably 60 ° ≦ θ2 ≦ 120 °.

<Description of turbulent flow>
Next, the state of turbulent flow will be described.

  7 is a cross-sectional view schematically showing a state where turbulent flow is generated by the first fin, FIG. 8 is a plan view schematically showing a state where turbulent flow is generated by the second fin according to the comparative example, and FIG. It is a top view which shows roughly the state which a turbulent flow generate | occur | produces with the 2nd fin which concerns on the 1st Embodiment of this invention.

  As shown in FIG. 7, with the rotation of the pneumatic tire 1, the air flow S <b> 1 that has been in contact with the general surface 8 a of the tire side portion 8 where the first fin 11 of the turbulent flow generation fin 10 is not formed is formed. When the first fin 11 is peeled off from the general surface 8a and over the first fin 11, a turbulent flow is generated. At this time, a portion (region) S <b> 2 where the air flow stays is generated on the back side in the flow direction of the first fin 11. Then, the air flow (turbulent flow) S <b> 1 reattaches to the bottom portion (general surface 8 a) between the next first fin 11 and is separated again by the next first fin 11. At this time, a region S <b> 3 where the air flow stays is generated between the air flow S <b> 1 and the next first fin 11. Here, it is considered that increasing the speed on the region where the turbulent flow S1 comes into contact is advantageous for increasing the heat dissipation rate.

  On the other hand, when the second fin extending in the tire circumferential direction is provided, turbulent flow in various directions is generated, and thus air flows as shown in FIGS.

  When the pneumatic tire 1 rotates, as described with reference to FIG. 7, the air flow S1 generated by the rotation overcomes the first fin 11 to generate turbulent flow, and the first fins 11 and 11 shown in FIGS. This region is the temperature reduction region T because it hits the tire side portion 8 in the region between. Furthermore, since the turbulent flow S1 over the first fin 11 flows toward the outer side in the tire radial direction, cooling by heat exchange is promoted.

  Here, in FIG. 8, since the second fins 18 are formed at the same height at any part in the tire circumferential direction, the air flow that flows over the first fins 11 toward the outer side in the tire radial direction is the second. An airflow stagnation region A that stagnates on the upstream side (inner side in the tire radial direction) of the fin 18 is formed in a wide range. As a result, the flow rate of the air flow S2 over the second fin 18 is reduced.

  On the other hand, in FIG. 9, since the height of the intermediate portion in the tire circumferential direction is set to be lower than the height of both end portions in the tire circumferential direction, the second fin 12 overcomes the first fin 11 described above and extends in the tire radial direction. The air flow S1 flowing toward the outside becomes S2 without being inhibited by the second fins 12, the air flow stagnation region A becomes very small, the heat exchange efficiency is improved, and the temperature reduction region T is expanded.

<Operation effect>
(1) In the present embodiment, the turbulent flow generation fin 10 extends in the tire radial direction, and a plurality of first fins 11 provided at predetermined intervals in the tire circumferential direction, and in the tire circumferential direction. The second fin 12 is provided between the adjacent first fins 11 and 11 and extends in the tire circumferential direction. The second fin 12 has a height hc at the intermediate portion 13 in the tire circumferential direction. It is set lower than the height Hc at the end 14 in the tire circumferential direction.

  Accordingly, the effect of reducing the temperature of the tire side portion 8 when the vehicle is running is further enhanced. This will be specifically described below.

  When the pneumatic tire 1 rotates, as shown in FIG. 9, the air flow generated by the rotation overcomes the first fin 11 and becomes a turbulent flow, and hits the tire side portion 8 in the region between the first fins 11 and 11. Therefore, this region becomes the temperature reduction region T. Further, since the turbulent flow S1 over the first fin 11 flows toward the outer side in the tire radial direction by the traveling wind accompanying traveling of the vehicle, cooling by heat exchange is promoted.

  Here, as shown in FIG. 8, when the second fins 18 are formed at the same height at any part in the tire circumferential direction, the air flows over the first fins 11 toward the outer side in the tire radial direction. As a result of the air flow stagnation region A where the flow S1 stagnates upstream of the second fin 18 (in the tire radial direction) formed in a wide range, the flow rate of the air flow S2 over the second fin 18 is reduced.

  Therefore, as in the present invention, the second fin 12 is set such that the height hc of the intermediate portion 13 in the tire circumferential direction is set lower than the height Hc of the both ends 14 and 14 in the tire circumferential direction. The air flow S2 that flows over the tire and toward the outer side in the tire radial direction is not obstructed by the second fins 12, so that the air flow stagnation region A becomes very small, the heat exchange efficiency is improved, and the temperature reduction region T is expanded. .

(2) The second fin 12 arranged on the innermost side in the tire radial direction is installed at a position where the height from the upper end of the rim flange is 50 mm to 200 mm in a state where the second fin 12 is incorporated into a normal rim defined by TRA with a normal internal pressure. It is preferable that Since heat generation at the bead portion near the rim flange is large and rubber deterioration is most likely to occur near the flange of the rim, placing the second fin 12 at the above position effectively alleviates the temperature reduction effect at the tire side portion 8. Can be made.

(3) When the ratio hc / Hc between the height Hc and hc in the second fin 12 is 0.5 or less, the part surrounded by the first fin 11 and the second fin 12 is entirely heat-exchanged. High temperature reduction effect.

  The width W of the first fin 11 is preferably set to 2 to 10 mm. If it is less than 2 mm, high strength is not maintained and there is a risk of vibration due to the air flow. On the other hand, if it exceeds 10 mm, the heat storage amount of the first fin 11 will increase too much.

(4) The heights Hr and Hc are preferably set to 3 mm or more and 20 mm or less. In this case, for example, a predetermined heat dissipation characteristic can be exhibited within the practical speed range of the tire for construction vehicles.

(5) As described above, the relationship among Hr, Hc, P, and W is 1 ≦ P / Hr ≦ 20, 1 ≦ P / Hc ≦ 20, and 1 ≦ (P−W) / W ≦ 100. Is preferred. Thus, by setting the value of P to a predetermined value, the effect of changing the air flow to turbulent flow is reduced, and it is difficult to efficiently generate turbulent flow by the fins. Further, (P−W) / W indicates the ratio of the width W of the first fin 11 to P. If this value is too small, the first relative to the area of the general surface 8a of the tire side portion 8 where heat dissipation is desired to be improved. It is equivalent to the ratio of the surface area of the fin 11 being equal. The turbulent flow generating fin 10 is made of rubber, and even if the surface area is increased, the effect of improving heat dissipation is not obtained so much. Therefore, the minimum value of (P−W) / W is preferably 1.

(6) The aforementioned angle θ1 is preferably −30 ° ≦ θ1 ≦ 30 °, and the angle θ2 is preferably 60 ° ≦ θ2 ≦ 120 °. As a result, the temperature at the tire side portion 8 can be reduced by efficiently utilizing the rotational wind obtained by the rotation of the tire and the translational wind obtained by running the vehicle.

[Second Embodiment]
Next, a second embodiment will be described, but the description of the same structure as that of the first embodiment described above will be omitted.

  FIG. 10 is a perspective view showing a cross section of a main part of a pneumatic tire according to a second embodiment of the present invention, and FIG. 11 is a perspective view of the turbulent flow generating fin of FIG. 10 viewed from the inside in the tire radial direction.

  In this embodiment, the 2nd fin is arrange | positioned in the state which the division body divided | segmented into plurality was mutually spaced apart along the tire circumferential direction.

  As shown in FIG. 10, in the pneumatic tire 101 according to the present embodiment, a turbulent flow generation fin 110 is provided in the tire side portion 8. As shown in FIGS. 10 and 11, the turbulent flow generation fin 110 includes a first fin 111 extending in the tire radial direction from the vicinity of the bead core 2 to the shoulder portion 7 and a pair of first fins 111 adjacent to each other in the tire circumferential direction. , 111 and a second fin 112 extending along the tire circumferential direction.

  As shown in FIG. 11, the second fin 112 has a plurality of (two in the present embodiment) divided bodies 113 and 114 arranged at predetermined intervals in the tire circumferential direction. Specifically, the divided bodies 113 and 114 are both plate-like members formed in a substantially rectangular shape when viewed from the front, and are disposed between the pair of first fins 111 and 111 adjacent in the tire circumferential direction. In addition, a predetermined gap 115 is formed between the divided body 113 and the first fin 111, and a gap 116 is formed between the divided body 113 and the divided body 114, and the divided body 114 and the first fin 111 A gap 115 is formed between them.

  FIG. 12 is a perspective view of a modified example of the turbulent flow generating fin according to the second embodiment of the present invention as seen from the inner side in the tire radial direction.

  In this modification, the second fin 122 includes a plurality of (two in the present embodiment) divided bodies 123 and 124 arranged at predetermined intervals in the tire circumferential direction, and each divided body. 123 and 124, the height hc of the end portions 123b and 124b on the intermediate side is set lower than the height Hc of the end portions 123a and 124a on the first fin 111 side. Further, gaps 115 and 116 are formed between the divided bodies 123 and 124 and the first fins 111.

<Operation effect>
(1) The said 2nd fin 112 is arrange | positioned and arrange | positioned in the state spaced apart from each other along the tire circumferential direction by dividing | segmenting the division bodies 113 and 114 divided into plurality. In this way, by configuring the second fin 112 with the plurality of divided bodies 113 and 114, air flow circulates from the gap around the divided bodies 113 and 114, and turbulent flow generation from various directions is promoted. The temperature reduction effect in the tire side part 8 can be improved.

(2) The divided bodies 123 and 124 constituting the second fin 122 are set such that the height hc on the intermediate side 124b in the tire circumferential direction is lower than the height Hc on the end side 124a in the tire circumferential direction. Therefore, as described above, the action of the air flow from the gap around the divided bodies 123 and 124 is promoted more than when the height of the divided bodies 113 and 114 is set to be the same in each part in the tire circumferential direction. .

[Third embodiment]
Next, the third embodiment will be described, but the description of the same structure as the first and second embodiments described above will be omitted.

  FIG. 13 is a perspective view showing a cross section of the main part of a pneumatic tire according to a third embodiment of the present invention, and FIG. 14 is a perspective view of the turbulent flow generating fin of FIG. 13 viewed from the inside in the tire radial direction.

  In the pneumatic tire 201 according to the present embodiment, the divided bodies 213, 214, and 215 constituting the second fin 211 are divided into three or more (three in the present embodiment) along the tire circumferential direction. The height of the divided body 215 arranged on the intermediate side in the circumferential direction is set lower than the divided bodies 213 and 214 on the end side in the tire circumferential direction.

  That is, the second fin 212 is composed of three divided bodies 213, 214, and 215 arranged along the tire circumferential direction. Divided bodies 213 and 214 are arranged on both sides in the tire circumferential direction, and a divided body 215 is arranged between these divided bodies 213 and 214. The height hc of the intermediate divided body 215 is set to be lower than the height Hc of the divided bodies 213 and 214 on both sides. A gap 115 is formed between the divided body 213 and the first fin 111, and a gap 115 is formed between the divided body 214 and the first fin 111. Further, a gap 116 is formed between the divided body 213 and the divided body 215, and a gap 116 is formed between the divided body 214 and the divided body 215.

<Operation effect>
The divided bodies 213, 214, and 215 constituting the second fin 212 are divided into three along the tire circumferential direction, and the height hc of the divided body 215 disposed on the intermediate side in the tire circumferential direction is the tire. It is set lower than the height Hc of the divided bodies 213 and 214 arranged on the end side in the circumferential direction. Therefore, the height hc of the divided body 215 disposed on the intermediate side and the length of the divided body 215 along the tire circumferential direction can be easily changed.

[Fourth Embodiment]
Next, the fourth embodiment will be described, but the description of the same structure as the first to third embodiments described above will be omitted.

  In the pneumatic tire 301 according to the present embodiment, in the plurality of divided bodies constituting the second fin, the divided body arranged on the intermediate side in the tire circumferential direction is more than the divided body on the end side in the tire circumferential direction. The division body which is set to a low height and is arranged on the intermediate side is arranged on the outer side in the tire radial direction than the division body on the end side.

  FIG. 15 is a perspective view showing a cross section of the main part of a pneumatic tire according to a fourth embodiment of the present invention, and FIG. 16 is a perspective view of the turbulent flow generating fin of FIG. 15 viewed from the inside in the tire radial direction.

  Specifically, the turbulent flow generation fin 310 according to the present embodiment includes a first fin 311 and a second fin 312. The second fin 312 includes three divided bodies 313, 314, and 315 arranged along the tire circumferential direction. The height hc of the divided body 315 arranged on the center side in the tire circumferential direction is set to be lower than the height Hc of the divided bodies 313 and 314 arranged on both sides. Further, the central divided body 315 is arranged on the outer side in the tire radial direction than the divided bodies 313 and 314 arranged on both sides.

<Operation effect>
(1) In the divided body constituting the second fin 312, the divided body 315 arranged on the intermediate side in the tire circumferential direction is arranged on the outer side in the tire radial direction than the divided bodies 313 and 314 on the end side in the tire circumferential direction. Has been. Accordingly, the gap between the divided body 315 arranged on the intermediate side and the divided bodies 313 and 314 on the end side is increased, and the generation of turbulent flow around each divided body 313 to 315 is further promoted.

(2) A predetermined gap is provided between the first fins 11, 111, 211, 311 and the second fins 12, 112, 122, 212, 312 shown in the first to fourth embodiments. Since 15 and 115 are provided, the air flow circulates through these gaps 15 and 115, and the generation of turbulent flow is further promoted.

[Other embodiments]
It should not be understood that the descriptions and drawings which form part of the disclosure of the above-described embodiments limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in each of the embodiments described above, an ORR tire used for a construction vehicle is described as an example of a pneumatic tire. However, other off-the-road radial (ORR) tires, other truck bus radial (TBR) tires, and the like have been described. Of course, it can be applied to tires of the type. Further, a plurality of second fins 12 extending in the tire circumferential direction are provided between the first fins 11 adjacent to each other in the tire circumferential direction at predetermined intervals in the tire radial direction, and the circumferential center of these second fins 12 is provided. The aspect which sets the height of a part lower than the height of the edge part side in the vicinity of the 1st fin 11 is employable. Further, a plurality of (for example, four or more) divided bodies obtained by dividing the second fin 212 extending in the tire circumferential direction at a predetermined interval between the first fins 211 and 211 adjacent in the tire circumferential direction. The height of the divided body arranged on the circumferential center side of these second fins 212 is set lower than the height of the divided body arranged on the end side in the vicinity of the first fin 211. Can also be adopted.

  Hereinafter, the present invention will be described in more detail through examples.

  Using the pneumatic tires according to the conventional examples, comparative examples 1 and 2, and inventive examples 1 to 5, experiments were performed to compare temperature differences in the tire side portions.

  The tire size of the pneumatic tire used for each was 53 / 80R63. As shown in FIG. 17, the pneumatic tire 401 according to the conventional example has no turbulent flow generating fins on the tire side portion 8. As shown in FIGS. 18 and 19, the pneumatic tire 501 according to the comparative example 1 is provided with only the first fins 11 extending in the tire radial direction among the turbulent flow generating fins. As shown in FIGS. 20 and 21, the pneumatic tire 601 according to the comparative example 2 is provided with the turbulent flow generation fins 610 including the first fins 11 and the second fins 612. The height of the two fins 612 was formed so as to be the same at any part in the tire circumferential direction. The pneumatic tire according to Example 1 of the present invention is provided with the turbulent flow generating fin 10 shown in FIGS. 2 and 3. The pneumatic tire according to Example 2 of the present invention is provided with the turbulent flow generating fins 110 shown in FIGS. 10 and 11. The pneumatic tire according to Example 3 of the present invention was provided with the turbulent flow generation fin shown in FIG. The pneumatic tire according to Example 4 of the present invention is provided with the turbulent flow generating fins 210 shown in FIGS. 13 and 14. The pneumatic tire according to Example 5 of the present invention is provided with the turbulent flow generating fins 310 shown in FIGS. 15 and 16.

Each of these pneumatic tires is incorporated into a TRA regular rim, and is run on a drum with a diameter of 5 m at a load of 80% of the normal load and a normal internal pressure at a speed of 20 km / h. Was applied from the front side in the rotational direction of the tire. After that, after running for 24 hours, a thermocouple was inserted into the 20 mm area on the flange from a previously formed pore, and the temperature was measured at 6 areas on the circumference of the folded ply 5 mm on the circumference. Was calculated. The results are shown in Table 1 below. In Table 1, P / Hr of the first fin is a value at a site where the distance from the rim flange is 200 mm, and P / Hc of the second fin is a value at a site of the maximum height of the second fin. It is.

  From the results in Table 1, it was found that the temperatures of Invention Examples 1 to 5 were lower than those of the conventional example and Comparative Examples 1 and 2.

8 ... Tire side parts 10, 110, 210, 310 ... Turbulence generating fins 11, 16, 111, 211, 311 ... First fins 12, 112, 122, 212, 312 ... Second fins 13 ... Intermediate part 14 ... End portion 15, 115, 116 ... gap 113, 114, 123, 124, 213 to 215, 313 to 315 ... divided body 124a ... end portion side 124b ... intermediate side

Claims (6)

A pneumatic tire provided with a turbulent flow generating fin protruding in the tire width direction on a tire side portion disposed on a side surface of the tire,
The turbulent flow generating fin is:
A plurality of first fins extending in the tire radial direction and provided at a predetermined interval in the tire circumferential direction;
A second fin provided between the first fins adjacent in the tire circumferential direction and extending in the tire circumferential direction;
The pneumatic tire according to claim 2, wherein the second fin has a height at an intermediate portion in the tire circumferential direction set lower than an end portion in the tire circumferential direction.   2. The pneumatic tire according to claim 1, wherein the second fin is arranged in a state in which a plurality of divided bodies are separated from each other along a tire circumferential direction.   3. The pneumatic tire according to claim 2, wherein the divided body constituting the second fin has an intermediate height in the tire circumferential direction set lower than an end side in the tire circumferential direction. .   The divided body constituting the second fin is divided into three or more along the tire circumferential direction, and the height of the divided body arranged on the intermediate side in the tire circumferential direction is on the end side in the tire circumferential direction. The pneumatic tire according to claim 2, wherein the pneumatic tire is set lower than the divided body.   The divided body constituting the second fin is characterized in that the divided body arranged on the intermediate side in the tire circumferential direction is arranged on the outer side in the tire radial direction than the divided body on the end side in the tire circumferential direction. The pneumatic tire according to claim 4.   The pneumatic tire according to claim 1, wherein a predetermined gap is provided between the first fin and the second fin.

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