JP2010163143A - Run flat tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a run flat tire capable of effectively restraining a temperature rise in a tire side part when internal pressure reduces, particularly when having reinforcing rubber in the tire side part for restraining deformation of the tire side part when the internal pressure reduces. <P>SOLUTION: This run flat tire 1 has the reinforcing rubber 30 in the tire side part 70 for restraining the deformation of the tire side part 70 when the internal pressure reduces. The run flat tire 1 has a projection part 100 projecting outward in the tread width direction from an outside surface 71 of the tire side part 70. The projection part 100 is arranged in a reinforcing rubber arranging area RG extending along the tire peripheral direction and being an area between the outside end 31 in the tire radial direction of the reinforcing rubber 30 and the inside end 33 in the tire radial direction of the reinforcing rubber 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a run-flat tire provided with a reinforced rubber that suppresses deformation of a tire side portion when an internal pressure is reduced.

  Conventionally, in a pneumatic tire attached to an automobile or the like, a turbulent flow uneven part extending along the tire radial direction on the outer side surface of the tire side part in order to suppress the heat generation of the tire side part accompanying the traveling of the automobile There is known a structure for providing the pit (for example, Patent Document 1).

  The uneven portion for generating turbulence causes turbulence in the air flowing along the outer surface of the tire side portion as the pneumatic tire rolls. In other words, the air flowing along the outer side surface of the tire side part gets over the uneven part for generating turbulent flow, and the air whose flow is disturbed reattaches to the outer side surface of the tire side part, thereby promoting the heat radiation of the tire side part. Is done.

International Publication No. 2007/032405 (page 6-7, Fig. 2)

  By the way, in recent years, run flat tires including a reinforcing rubber in a tire side portion have become widespread in order to enable running even when the internal pressure of a pneumatic tire is significantly reduced, such as puncture.

  When such a run-flat tire is provided with the above-described uneven portion for generating turbulent flow, heat radiation at the tire side portion is promoted, so that a certain effect of suppressing the temperature rise is naturally recognized. However, particularly during traveling when the internal pressure is reduced, a great burden is placed on the reinforcing rubber, so that the temperature of the tire side portion is increased significantly, and more effective heat dissipation from the tire side portion has been desired.

  Therefore, the present invention provides a run-flat tire that can effectively suppress the temperature rise of the tire side portion when the internal pressure is reduced, particularly when the tire side portion is provided with a reinforcing rubber that suppresses deformation of the tire side portion when the internal pressure is reduced. The purpose is to provide.

  In order to solve the above-described problems, the present invention has the following features. First, a first feature of the present invention is a run-flat tire (for example, a run-flat tire) that includes a reinforcing rubber (reinforcing rubber 30) that suppresses deformation of the tire side portion (tire side portion 70) when the internal pressure is reduced. The tire 1) includes a protrusion (protrusion 100) that protrudes from the outer surface (outer surface 71) of the tire side portion toward the outer side in the tread width direction, and the protrusion extends along the tire circumferential direction. Reinforcing rubber that extends and is a region between a tire radial outer end (tire radial outer end 31) of the reinforcing rubber and a tire radial inner end (tire radial inner end 33) of the reinforcing rubber The gist is to be provided in the arrangement region (reinforced rubber arrangement region RG).

  In general, when running at normal internal pressure (so-called normal running), compared to running when the internal pressure is reduced (so-called punk running), the tire side portion of the run-flat tire does not bend. The diameter at the portion that does not contact the road surface is substantially the same as the diameter at the portion where the run flat tire contacts the road surface. On the other hand, in running when the internal pressure is reduced, the tire flat portion of the run flat tire bends so that the diameter at the portion where the run flat tire does not contact the road surface is larger than the diameter at the portion where the run flat tire contacts the road surface. growing.

  For this reason, the run-flat tire in running when the internal pressure is reduced rolls while the tire side portion is largely bent. In other words, in the run flat tire in traveling when the internal pressure is reduced, the diameter of the protrusion moves in the tire radial direction in the side view seen from the rotation axis direction of the run flat tire.

  As a result, turbulent flow is likely to occur at the bent portion where the reinforcing rubber is bent at a portion where the run-flat tire is in contact with the road surface, particularly at a temperature where the temperature rises rapidly. Therefore, the air flowing in the tire radial direction is disturbed by the protrusions extending along the tire circumferential direction, and the temperature increase of the tire side portion when the internal pressure is reduced can be effectively suppressed.

  In addition, air generated as the vehicle travels flows from the front to the rear of the vehicle. For this reason, the protrusion part extended along a tire circumferential direction opposes (substantially orthogonal) with the air which generate | occur | produces with driving | running | working of a vehicle. As a result, the air generated as the vehicle travels is more likely to be disturbed by the projections extending along the tire circumferential direction than when the projections extend along the tire radial direction, and the air pressure is reduced. The temperature rise of the tire side portion can be further effectively suppressed.

  In particular, by providing the protrusions in the reinforcing rubber arrangement region, it is possible to effectively suppress an increase in the temperature of the tire side portion when the internal pressure is reduced, in particular, an increase in the temperature of the reinforcing rubber (bent portion) that easily rises in temperature. Accordingly, the durability of the reinforcing rubber when the internal pressure is reduced is improved, and the distance that can be traveled with the internal pressure reduced is increased.

  A second feature of the present invention relates to the first feature of the present invention, and is provided with a carcass (carcass 20) forming a skeleton of the run-flat tire, wherein the protrusion is in the tread width direction of the run-flat tire. The gist of the present invention is that it is provided in the maximum curvature region (maximum curvature region MR) including the maximum curvature position (maximum curvature position R1) where the curvature of the carcass is the largest in the cross section along.

  A third feature of the present invention relates to the second feature of the present invention, wherein the protrusion is formed of the reinforcing rubber along a direction perpendicular to the carcass in a cross section along the tread width direction of the run-flat tire. The thickness (t) is provided in the maximum thickness region (maximum thickness region MT) including the thickest position (maximum thickness position t1).

  A fourth feature of the present invention is related to the first to third features of the present invention, and is summarized in that the protrusion continuously extends along a tire circumferential direction.

  A fifth feature of the present invention relates to the first to fourth features of the present invention, wherein a tire radial outer end of the reinforcing rubber and an inner radial end of the reinforcing rubber along the outer surface of the tire side portion. Is the reinforcing rubber length S, the tire radial direction outer side is the plus side and the tire radial direction inner side is the minus side with reference to the maximum curvature position, and the protrusions are +0.2 S to −0. The gist is that it is provided within the range of 2S.

  A sixth feature of the present invention relates to the first to fifth features of the present invention, wherein a height h of the projection from the outer surface is 0.5 mm to 7.0 mm, and the projection The gist of the width w in the tire radial direction is 1.0 mm to 5.0 mm.

  A seventh feature of the present invention relates to the first to sixth features of the present invention, wherein a plurality of the projecting portions are provided in the tire radial direction, and a distance between central portions of the projecting portions adjacent to each other in the tire radial direction is provided. P and the height h of the protrusion from the outer surface satisfy 8 ≦ P / h ≦ 16, and the interval P and the width w of the protrusion in the tire radial direction are 1.0. The gist is to satisfy ≦ (P−w) / w <P.

  An eighth feature of the present invention is according to the seventh feature of the present invention, wherein a tire radial outer end of the reinforcing rubber and a tire radial inner end of the reinforcing rubber along the outer surface of the tire side portion are provided. When the length is the reinforced rubber length S, the outer side in the tire radial direction is the plus side and the inner side in the tire radial direction is the minus side with reference to the maximum curvature position, at least a part of the protrusion is +0.15 S The gist is to be within the range of -0.15S.

  According to the features of the present invention, in the case where the tire side portion is provided with a reinforced rubber that suppresses deformation of the tire side portion when the internal pressure is reduced, in particular, the run that can effectively suppress the temperature rise of the tire side portion when the internal pressure is reduced. A flat tire can be provided.

FIG. 1 is a partial perspective view showing a run-flat tire 1 according to the first embodiment. FIG. 2 is a cross-sectional view of the run flat tire 1 according to the first embodiment along the tread width direction. FIG. 3 is a side view of the run flat tire 1 according to the first embodiment viewed from the direction of the rotation axis. FIG. 4 is a perspective view showing the protrusion 100 according to the first embodiment. FIG. 5 is a cross-sectional view along the tire radial direction of the protrusion 100 according to the first embodiment. FIG. 6 is a side view of the run flat tire 500 according to Comparative Example 2 viewed from the direction of the rotation axis. FIG. 7 is a view for explaining the operation and effect of the run-flat tire 1 according to the first embodiment. FIG. 8 is a cross-sectional view of the protrusion 200 according to the modification along the tire radial direction. FIG. 9 is a partial perspective view showing a run flat tire 1A according to the second embodiment. FIG. 10 is a cross-sectional view along the tread width direction of the run flat tire 1A according to the second embodiment. FIG. 11 is a side view of the run flat tire 1A according to the second embodiment as viewed from the direction of the rotation axis. FIG. 12 is a perspective view showing a protrusion 100A according to the second embodiment. FIG. 13 is a cross-sectional view of the protrusion 100A according to the second embodiment along the tire radial direction.

  Hereinafter, a run flat tire according to the present invention will be described with reference to the drawings. Specifically, the first embodiment, the second embodiment, and other embodiments 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, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First Embodiment]
First, the configuration of the run flat tire according to the first embodiment of the present invention will be described with reference to the drawings. Specifically, (1) the configuration of the run-flat tire, (2) the configuration of the protrusion, (3) comparative evaluation, (4) action / effect, and (5) a modification of the protrusion will be described.

(1) Configuration of Run Flat Tire First, the configuration of the run flat tire 1 according to the first embodiment will be described with reference to the drawings. FIG. 1 is a partial perspective view showing a run-flat tire 1 according to the first embodiment. FIG. 2 is a cross-sectional view of the run flat tire 1 according to the first embodiment along the tread width direction. FIG. 3 is a side view of the run flat tire 1 according to the first embodiment viewed from the direction of the rotation axis.

  As shown in FIGS. 1 to 3, the run flat tire 1 includes a bead portion 10, a carcass 20, a reinforcing rubber 30, an inner liner 40, a belt 50, a tread 60, and a protruding portion 100.

(1-1) Bead part In the bead part 10, the run-flat tire 1 is fixed to a rim (not shown). The bead unit 10 includes at least a bead core 11 and a bead filler 13. The bead core 11 becomes the core of the bead unit 10. The bead filler 13 is provided between the carcass 20 where the bead core 11 is folded back, and suppresses deformation of the bead portion 10.

(1-2) Carcass The carcass 20 forms the skeleton of the run-flat tire 1. The carcass 20 is provided toward the other bead core 11 by folding the bead core 11 and passing from one bead core 11 to the inside of the tread 60 in the tire radial direction. The carcass 20 is composed of a carcass cord and rubber.

(1-3) Reinforcing Rubber The reinforcing rubber 30 suppresses deformation of the tire side portion 70 when the internal pressure is reduced. The reinforcing rubber 30 is provided inside the carcass 20 in the tread width direction in the cross-sectional view in the tread width direction. The reinforcing rubber 30 is formed of crescent-shaped rubber in the cross-sectional view in the tread width direction.

(1-4) Inner liner The inner liner 40 is formed of a highly airtight rubber layer serving as a tube. The inner liner 40 is provided inside the carcass 20 and the reinforcing rubber 30.

(1-5) Belt The belt 50 reinforces the tread 60 while maintaining the shape of the run-flat tire 1. The belt 50 is provided outside the carcass 20 in the tire radial direction. A plurality of belts 50 are provided, and each belt 50 has a belt shape along the tire circumferential direction.

(1-6) Tread The tread 60 has a tread pattern and is in contact with the road surface. The tread 60 is provided on the outer side of the belt 50 in the tire radial direction.

(1-7) Projection Part The projection part 100 suppresses the temperature rise of the tire side part 70. The protrusion 100 protrudes from the outer surface 71 of the tire side portion 70 toward the outer side in the tread width direction. The protrusion 100 extends continuously along the entire circumference in the tire circumferential direction.

(2) Configuration of Protrusion Next, the configuration of the protrusion 100 according to the first embodiment will be described with reference to the drawings. FIG. 4 is a perspective view showing the protrusion 100 according to the first embodiment. FIG. 5 is a cross-sectional view along the tire radial direction of the protrusion 100 according to the first embodiment.

  As shown in FIGS. 2 and 3, the protrusion 100 is formed in a reinforcing rubber arrangement region RG that is a region between the tire radial direction outer end 31 of the reinforcing rubber 30 and the tire radial direction inner end 33 of the reinforcing rubber. Provided.

  The protrusion 100 is provided in the maximum curvature region MR including the maximum curvature position R1 where the curvature of the carcass 20 is the largest in the reinforcing rubber arrangement region RG in the cross section along the tread width direction of the run flat tire 1.

  In particular, the protrusion 100 is the thickest position where the thickness t of the reinforcing rubber 30 along the direction orthogonal to the carcass 20 is the largest in the maximum curvature region MR in the cross section along the tread width direction of the run-flat tire 1. It is preferable to be provided in the maximum thickness region MT including t1.

  Specifically, as shown in FIGS. 2 and 3, the length of the tire radial direction outer end 31 of the reinforcing rubber 30 and the tire radial direction inner end 33 of the reinforcing rubber 30 along the outer side surface 71 of the tire side portion 70. When the length is the reinforcing rubber length S and the maximum curvature position R1 is used as a reference, the outer side in the tire radial direction is the plus side, and the inner side in the tire radial direction is the minus side, the protrusion 100 has a range of + 0.2S to -0.2S. It is provided in the inside.

  The protrusion 100 has a substantially trapezoidal shape in a sectional view of the protrusion 100 along the tire radial direction (see FIG. 5). As shown in FIGS. 4 and 5, the protrusion 100 has an inner surface 101, an outer surface 103, and an upper surface 105.

  The inner side surface 101 is located on the inner side in the tire radial direction than the outer side surface 103 in the cross-sectional view of the protruding portion 100 along the tire radial direction. The inner side surface 101 has an inner projecting end 101A located on the outermost side in the tread width direction and an inner bottom end 101B located on the innermost side in the tread width direction. The inner side surface 101 is provided so as to be inclined with respect to the outer side surface 71 of the tire side portion 70 at the inner bottom end 101B.

  The outer side surface 103 is located on the outer side in the tire radial direction from the inner side surface 101 in the cross-sectional view of the protrusion 100 along the tire radial direction. The outer side surface 103 has an outer protruding end 103A located on the outermost side in the tread width direction, and an outer bottom end 103B located on the innermost side in the tread width direction. The outer side surface 103 is provided so as to be inclined with respect to the outer side surface 71 of the tire side portion 70 at the outer bottom end 103B.

  The upper surface 105 is located on the outer side in the tread width direction. The upper surface 105 connects the inner projecting end 101 </ b> A of the inner surface 101 and the outer projecting end 103 </ b> A of the outer surface 103. The upper surface 105 is provided along the outer surface 71 of the tire side portion 70.

  Here, the height h from the outer side surface 71 of the tire side part 70 of the protrusion part 100 is 0.5 mm-7.0 mm. The height h indicates the length along the tread width direction from the outer surface 71 of the tire side portion 70 to the inner protruding end 101A.

  Moreover, the width w in the tire radial direction of the protrusion 100 is 1.0 mm to 5.0 mm. The width w represents the length from the inner bottom end 101B to the outer bottom end 103B. The width w is longer than the length L of the upper surface 105 along the tire radial direction.

(3) Comparative Evaluation Next, in order to further clarify the effects of the present invention, comparative evaluation performed using run flat tires according to the following comparative examples and examples will be described. Specifically, (3-1) Configuration of each run-flat tire and (3-2) Evaluation result will be described. In addition, this invention is not limited at all by these examples.

(3-1) Configuration of Run Flat Tires First, the configuration of run flat tires according to comparative examples and examples will be briefly described. In addition, the data regarding a run flat tire were measured on the conditions shown below.

・ Tire size: 285 / 50R20
・ Rim size: 8JJ × 20
・ Internal pressure condition: 0kPa
・ Load condition: 9.8kN

  The run flat tire according to Comparative Example 1 is not provided with a protrusion. As shown in FIG. 6, the run-flat tire 500 according to the comparative example 2 is provided with a plurality of protrusions 501 that extend along the tire radial direction and are arranged at predetermined intervals in the tire circumferential direction. Note that the shape of the protrusion 501 is the same as the shape of the protrusion 100 described in the first embodiment.

  In the run flat tire 1 according to Example 1 (1-A to 1-W), the protruding portion 100 extending continuously along the tire circumferential direction described in the first embodiment is provided. In the run flat tire 1 according to Examples 1-A to 1-W, the configuration of the protrusion 100 (for example, the height h, the width w, and the arrangement region) is different.

(3-2) Evaluation result Next, the evaluation result using the run flat tire which concerns on the comparative example and Example mentioned above is demonstrated, referring Table 1-Table 3. FIG.

  In Table 1, the durability of the run flat tires according to Comparative Example 1 and Example 1 is shown with the durability of the run flat tire according to Comparative Example 2 as a reference (100).

  In Table 2, the run-flat tire 1 according to Examples 1-A to 1-H in which the height h and the width w of the protrusion 100 are different from each other on the basis of the durability of the run-flat tire according to Comparative Example 2 (100). Of durability.

  In Table 3, run-flats according to Examples 1-1 to 1-1W in which the height h, width w, and arrangement region of the protrusion 100 are different from the durability (100) of the run-flat tire according to Comparative Example 1 as a reference (100). The durability of the tire 1 is indicated.

  Here, in the tire durability test, each run flat tire was mounted on a test drum, and the endurance distance until the run flat tire broke down (for example, until separation occurred near the reinforcing rubber) was indexed. . The larger the value, the better the tire durability.

  As shown in Table 1, since the run flat tire 1 according to Example 1 can suppress the temperature rise of the tire side portion when the internal pressure is reduced, compared with the run flat tires according to Comparative Examples 1 and 2, durability of the tire is increased. It turns out that it is excellent in property.

  As shown in Table 2, in the run-flat tire 1 according to Examples 1-A to 1-H, the height h of the protrusion 100 is 0.5 mm to 7.0 mm, and the width w of the protrusion 100 is 1. By being 0.0 mm to 5.0 mm, the temperature rise of the tire side portion when the internal pressure is reduced can be efficiently suppressed, and thus it is understood that the tire has excellent durability.

  As shown in Table 3, the run flat tire 1 according to Examples 1-1 to 1-W has a tire side portion temperature increase when the internal pressure is reduced, as compared with the durability of the run flat tire according to Comparative Example 1. Since it can suppress efficiently, it turns out that it is excellent in the durability of a tire. In particular, in the run flat tire 1 according to Examples 1-1 to 1-W, the height h and the width w of the protrusion 100 are in the above-described ranges, and the protrusion 100 is + 0.2S to -0.2S. It can be seen that by being provided within the range, the temperature rise of the tire side portion when the internal pressure is reduced can be efficiently suppressed.

(4) Action / Effect Generally, in running at normal internal pressure (so-called normal running), the tire side portion of the run-flat tire does not bend compared to running at lower internal pressure (so-called punk running). Therefore, the diameter (R ₀ ) at the portion where the run flat tire does not contact the road surface is substantially the same as the diameter (R ₁ ) at the portion where the run flat tire contacts the road surface. On the other hand, in running when the internal pressure is reduced, as shown in FIGS. 7A and 7B, the run-flat tire 1 is brought into contact with the road surface as the tire side portion 70 of the run-flat tire 1 bends. The diameter (R ₀ ) at the non-contact portion is larger than the diameter (R ₁ ) at the portion where the run-flat tire 1 is in contact with the road surface (R ₀ > R ₁ ).

  For this reason, the run-flat tire 1 in running when the internal pressure is reduced rolls while the tire side portion 70 is greatly bent. In other words, in the run flat tire 1 during traveling when the internal pressure is reduced, the diameter of the protrusion 100 moves in the tire radial direction in the side view seen from the rotation axis direction of the run flat tire 1.

  As a result, turbulent flow is likely to occur at the bent portion 35 where the reinforcing rubber 30 is bent at a portion where the run-flat tire 1 is in contact with the road surface, particularly where the temperature rises rapidly. Accordingly, the air flowing in the tire radial direction is disturbed by the protrusions 100 extending along the tire circumferential direction, and the temperature rise of the tire side portion 70 when the internal pressure is reduced can be effectively suppressed.

  Further, air generated as the vehicle travels flows from the front to the rear of the vehicle. For this reason, the protrusion part 100 extended along a tire circumferential direction opposes (substantially orthogonal) with the air which generate | occur | produces with driving | running | working of a vehicle. As a result, the air generated as the vehicle travels is more likely to be disturbed by the protrusions 100 extending along the tire circumferential direction than when the protrusions extend along the tire radial direction, and the internal pressure is reduced. The temperature rise of the tire side portion 70 can be more effectively suppressed.

  In particular, the protrusion 100 is provided in the reinforcing rubber arrangement region RG, thereby effectively increasing the temperature of the tire side portion 70 when the internal pressure is decreased, and in particular, increasing the temperature of the reinforcing rubber 30 (bending portion 35) whose temperature is likely to increase. Can be suppressed. Therefore, the durability of the reinforcing rubber 30 when the internal pressure is reduced is improved, and the distance that can be traveled with the internal pressure reduced is increased.

  Hereinafter, the flow of air over the protrusion 100 will be briefly described. As shown in FIG. 5, the air S <b> 1 flowing along the outer side surface 71 of the tire side portion 70 as the run-flat tire 1 rolls over the protrusion 100, and the air S <b> 1 whose flow is disturbed becomes the tire side portion 70. It adheres to the outer side surface 71 again, and the heat radiation of the tire side portion 70 is promoted. Furthermore, when the air S1 collides with the protrusion 100, the heat dissipation of the protrusion 100 itself is also promoted.

  Further, the air S2 staying on the inner surface 101 side against which the air S1 strikes and the air S3 staying on the outer surface 103 (back surface) side opposite to the inner surface 101 are located in the vicinity of the inner surface 101 and the outer surface 103. The heat of the outer side surface 71 of the side portion 70 is taken and merged with the air S1, and the heat radiation of the tire side portion 70 is further promoted.

  In the first embodiment, the protrusion 100 is provided in the maximum curvature region MR including the maximum curvature position R1. In particular, the protrusion 100 is preferably provided in the maximum thickness region MT including the maximum thickness position t1 where the thickness t of the reinforcing rubber 30 is the thickest in the maximum curvature region MR. According to this, in the travel at the time when the internal pressure is reduced, the bent portion 35 (see FIG. 7 (FIG. 7 (B) where the reinforcing rubber 30 that is assumed to have the highest temperature rise is bent as the tire side portion 70 of the run-flat tire 1 bends). A protrusion 100 is provided in the vicinity of a). For this reason, the heat radiation of the bent portion 35 is promoted, and the temperature rise of the tire side portion 70 can be more efficiently suppressed.

  In the first embodiment, the protrusion 100 continuously extends along the entire circumference in the tire circumferential direction. According to this, compared with the case where the projection part 100 is provided intermittently in the tire circumferential direction, it can be expected that the temperature rise of the tire side part 70 can be efficiently suppressed over the entire circumference in the tire circumferential direction.

  In the first embodiment, the protrusion 100 is provided in the range of + 0.2S to −0.2S. According to this, in the traveling at the time when the internal pressure is reduced, the bending portion 35 (see FIG. 7) of the reinforcing rubber 30 that is assumed to have the highest temperature rise as the tire side portion 70 of the run flat tire 1 bends. A protrusion 100 is provided in the vicinity. For this reason, the heat radiation of the bent portion 35 is promoted, and the temperature rise of the tire side portion 70 can be more efficiently suppressed.

  In 1st Embodiment, the height h from the outer surface 71 of the tire side part 70 of the projection part 100 is 0.5 mm-7.0 mm. If the height h is smaller than 0.5 mm, the flow of air over the protrusion 100 is weakened, and the momentum of the air adhering to the outer surface 71 is weakened. There is. On the other hand, if the height h is greater than 7.0 mm, the air over the protrusion 100 may escape from the outer surface 71 of the tire side portion 70 to the outside in the tread width direction, and heat dissipation from the tire side portion 70 may not be promoted. is there.

  In the first embodiment, the width w of the protrusion 100 in the tire radial direction is 1.0 mm to 5.0 mm. If the width w is smaller than 1.0 mm, the flow of air over the projection 100 is weakened, and the momentum of the air adhering to the outer surface 71 is weakened. is there. On the other hand, if the width w is larger than 5.0 mm, it is difficult to promote the heat dissipation of the protrusion 100 itself, and thus the heat dissipation of the tire side portion 70 may not be promoted.

(5) Modification of Protrusion Part The protrusion part 100 according to the first embodiment described above may be modified as follows. In addition, the same code | symbol is attached | subjected to the same part as the projection part 100 which concerns on 1st Embodiment mentioned above, and a different part is mainly demonstrated. FIG. 8 is a cross-sectional view of the protrusion 200 according to the modification along the tire radial direction.

  Here, the protrusion 100 according to the first embodiment described above has a substantially trapezoidal shape in a cross-sectional view of the protrusion 100 along the tire radial direction. On the other hand, the projection part 200 which concerns on a modification has comprised the shape different from the projection part 100 which concerns on 1st Embodiment in sectional drawing along the tire radial direction of the projection part 200. FIG.

(5-1) Modification 1
As shown in FIG. 8A, the protrusion 200A according to Modification 1 has a substantially trapezoidal shape in a sectional view of the protrusion 200A along the tire radial direction. Specifically, the inner protruding end 101A and the outer protruding end 103A are formed in an arc shape (R shape). That is, the inner side surface 101 and the upper surface 105 are connected in an arc shape. Similarly, the outer surface 103 and the upper surface 105 are connected in an arc shape.

(5-2) Modification 2
As shown in FIG. 8B, the protrusion 200B according to Modification 2 has a substantially square shape in a cross-sectional view of the protrusion 200B along the tire radial direction. Specifically, the inner side surface 101 and the outer side surface 103 are provided substantially at right angles to the outer side surface 71 of the tire side portion 70. The inner side surface 101 and the upper surface 105 are connected at a substantially right angle. Similarly, the outer surface 103 and the upper surface 105 are connected at a substantially right angle.

(5-3) Modification 3
As shown in FIG. 8C, the protrusion 200C according to Modification 3 has a quadrangular shape in a cross-sectional view of the protrusion 200C along the tire radial direction. Specifically, the inner side surface 101 is provided to be inclined with respect to the outer side surface 71 of the tire side portion 70. On the other hand, the outer surface 103 is provided at a substantially right angle to the outer surface 71 of the tire side portion 70.

(5-4) Modification 4
As shown in FIG. 8D, the protrusion 200D according to Modification 4 has a quadrangular shape in a cross-sectional view of the protrusion 200D along the tire radial direction. Specifically, the inner side surface 101 is provided at a substantially right angle with respect to the outer side surface 71 of the tire side portion 70. On the other hand, the outer surface 103 is provided so as to be inclined with respect to the outer surface 71 of the tire side portion 70.

(5-5) Modification 5
As shown in FIG. 8E, the protrusion 200E according to the modified example 5 has an arc shape (R shape) in a cross-sectional view of the protrusion 200E along the tire radial direction. In this case, the height h indicates the length along the tread width direction from the outer side surface 71 of the tire side portion 70 to the protruding position 107 that protrudes most outward in the tread width direction of the protrusion 200E.

[Second Embodiment]
Hereinafter, a run flat tire 1A according to a second embodiment of the present invention will be described with reference to the drawings. Specifically, (1) the structure of the protrusion, (2) comparative evaluation, and (3) action / effect will be described. In addition, the same code | symbol is attached | subjected to the same part as the run flat tire 1 which concerns on 1st Embodiment mentioned above, and a different part is mainly demonstrated.

(1) Configuration of Protrusion First, the configuration of the protrusion 100A provided in the run flat tire 1A according to the second embodiment will be described with reference to the drawings. FIG. 9 is a partial perspective view showing a run flat tire 1A according to the second embodiment. FIG. 10 is a cross-sectional view along the tread width direction of the run flat tire 1A according to the second embodiment.

  FIG. 11 is a side view of the run flat tire 1A according to the second embodiment viewed from the direction of the rotation axis. FIG. 12 is a perspective view showing a protrusion 100A according to the second embodiment. FIG. 13 is a cross-sectional view of the protrusion 100A according to the second embodiment along the tire radial direction.

  As shown in FIGS. 9 to 11, the protrusion 100 </ b> A extends continuously along the entire circumference in the tire circumferential direction. Plural protrusions 100A are provided in the tire radial direction. In the second embodiment, two protrusions 100A are provided in the tire radial direction.

  Even in this case, as shown in FIGS. 10 and 11, the protrusion 100 </ b> A is provided in the reinforcing rubber arrangement region RG. The protrusion 100A is provided in the maximum curvature region MR. In particular, the protrusion 100A is preferably provided in the vicinity of the maximum thickness region MT in the maximum curvature region MR.

  Specifically, the length of the tire radial direction outer end 31 of the reinforcing rubber 30 and the tire radial inner end 33 of the reinforcing rubber 30 along the outer side surface 71 of the tire side portion 70 is defined as the reinforcing rubber length S. In the case where the outer side in the tire radial direction is the plus side and the inner side in the tire radial direction is the minus side with respect to the maximum curvature position R1, at least a part of the protrusion 100A is provided within the range of + 0.15S to -0.15S. .

  Here, as shown in FIGS. 12 and 13, the interval P (so-called pitch) between the central portions in the tire radial direction of the protrusions 100 </ b> A adjacent to each other, and the height h from the outer surface 71 of the protrusion 100 </ b> A Satisfies 8 ≦ P / h ≦ 16, and the interval P and the width w of the protrusion 100A in the tire radial direction preferably satisfy 1.0 ≦ (P−w) / w <P. Moreover, it is preferable that the center position C of the space | interval P overlaps with the thickest position t1.

(2) Comparative Evaluation Next, in order to further clarify the effect of the present invention, comparative evaluation performed using run flat tires according to the following comparative examples and examples will be described. Specifically, (2-1) Configuration of each run-flat tire and (2-2) Evaluation result will be described. In addition, this invention is not limited at all by these examples.

(2-1) Configuration of Run Flat Tires First, the configuration of run flat tires according to comparative examples and examples will be briefly described. In addition, the data regarding a run flat tire were measured on the conditions shown below.

・ Tire size: 285 / 50R20
・ Rim size: 8JJ × 20
・ Internal pressure condition: 0kPa
・ Load condition: 9.8kN

  The run flat tires according to Comparative Examples 1 and 2 are the same as the run flat tires according to Comparative Examples 1 and 2 described in the first embodiment. That is, the run-flat tire according to Comparative Example 1 is not provided with a protrusion. The run flat tire 500 according to the comparative example 2 is provided with a plurality of protrusions 501 extending along the tire radial direction (see FIG. 6).

  In the run flat tire 1A according to Example 2 (2-A to 2-J), a plurality of protrusions 100A that continuously extend along the tire circumferential direction described in the second embodiment are provided in the tire radial direction. . In the run flat tire 1A according to Examples 2-A to 1-J, the configuration (for example, P / h, height h, arrangement region) of the protrusion 100A is different.

(2-2) Evaluation result Next, the evaluation result using the run flat tire which concerns on the comparative example and Example mentioned above is demonstrated, referring Table 4-Table 6. FIG.

  Table 4 shows the durability of the run flat tires according to Comparative Example 1 and Example 2 with the durability of the run flat tire according to Comparative Example 2 as a reference (100).

  In Table 5, the durability of the run flat tire 1A according to Examples 2-A to 2-E in which the P / h of the protrusion 100A is different from the durability of the run flat tire according to the comparative example 2 as a reference (100). Is shown. The P / h of the protrusion 100A was obtained by changing the height h of the protrusion 100A without changing the interval P between the protrusions 100A.

  In Table 6, the durability of the run-flat tire 1A according to Examples 2-F to 2-J in which the arrangement region of the protrusion 100A is different from the durability of the run-flat tire according to Comparative Example 1 as a reference (100). Indicated.

  Here, in the tire durability test, each run flat tire was mounted on a test drum, and the endurance distance until the run flat tire broke down (for example, until separation occurred near the reinforcing rubber) was indexed. . The larger the value, the better the tire durability.

  As shown in Table 4, the run flat tire 1A according to Example 2 can suppress an increase in temperature of the tire side portion when the internal pressure is reduced, compared with the run flat tires according to Comparative Examples 1 and 2, and thus durability of the tire. It turns out that it is excellent in property.

  As shown in Table 5, in the run flat tire 1A according to Examples 2-A to 2-E, the P / h of the protrusion 100A is 8 to 16, thereby increasing the temperature of the tire side portion when the internal pressure is reduced. It can be seen that the tire is excellent in durability.

  As shown in Table 6, the run flat tire 1A according to Examples 2-F to 2-J has an increase in the temperature of the tire side portion when the internal pressure is reduced, compared to the durability of the run flat tire according to Comparative Example 1. Since it can suppress efficiently, it turns out that it is excellent in the durability of a tire. In particular, in the run flat tire 1A according to Examples 2-F to 2-J, at least a part of the protrusion 100A is provided within the range of + 0.15S to -0.15S, so that the tire side when the internal pressure is reduced is reduced. It turns out that the temperature rise of a part can be suppressed efficiently.

(2) Action / Effect In the second embodiment, a plurality of protrusions 100A are provided in the tire radial direction. The protrusion 100A in which a diameter difference has occurred during traveling (so-called puncture traveling) when the internal pressure is reduced moves in the tire radial direction as compared to a protrusion that does not generate a diameter difference. Turbulence is likely to occur at the bent portion 35 (see FIG. 7) where the reinforcing rubber 30 is bent at a portion where the run-flat tire 1A is in contact with the road surface, particularly when the temperature of the reinforcing rubber 30 is sharp.

  For this reason, as shown in FIG. 12, the air S10 flowing along the outer side surface 71 of the tire side portion 70 as the run-flat tire 1A rolls over the protrusion 100A, and the air S10 whose flow is disturbed becomes the tire. It adheres to the outer surface 71 of the side part 70 again, and heat dissipation of the tire side part 70 is promoted. Furthermore, when the air S10 collides with the protrusion 100A, heat dissipation of the protrusion 100A itself is also promoted.

  Further, the air S20 staying on the inner surface 101 side against which the air S10 hits and the air S30 staying on the outer surface 103 (back surface) side opposite to the inner surface 101 are located near the inner surface 101 and the outer surface 103. The heat of the outer surface 71 of the side portion 70 is taken and merged with the air S10, and the heat radiation of the tire side portion 70 is further promoted.

  As described above, when the tire side portion is provided with the reinforcing rubber 30 that suppresses the deformation of the tire side portion 70 when the internal pressure is reduced, the temperature of the tire side portion 70 when the internal pressure is reduced, in particular, the temperature is likely to rise. The temperature rise of the reinforcing rubber 30 can be effectively suppressed. Therefore, the durability of the reinforcing rubber 30 when the internal pressure is reduced is improved, and the distance that can be traveled with the internal pressure reduced is increased.

  In the second embodiment, at least a part of the protrusion 100A is provided within the range of + 0.15S to -0.15S. According to this, in the traveling at the time when the internal pressure is reduced, the bending portion 35 (see FIG. 7) of the reinforcing rubber 30 that is assumed to have the highest temperature rise as the tire side portion 70 of the run flat tire 1 bends. A protrusion 100A is provided in the vicinity. For this reason, the heat radiation of the bent portion 35 is promoted, and the temperature rise of the tire side portion 70 can be more efficiently suppressed.

  In the second embodiment, the protrusion 100A preferably satisfies 8 ≦ P / h ≦ 16 and satisfies 1.0 ≦ (P−w) / w <P. If P / h is less than 8 and the height h is high, air hardly adheres between the central portions in the tire radial direction of the protrusions 100A adjacent to each other, and the temperature of the tire side portion 70 is efficiently increased. May not be able to be suppressed. On the other hand, when the height h is low when P / h is smaller than 16, the air S10 hardly collides with the protrusion 100A, and the temperature rise of the tire side portion 70 may not be efficiently suppressed.

  Further, if it deviates from 1.0 ≦ (P−w) / w <P, air does not adhere between the central portions in the tire radial direction of the protrusions 100A adjacent to each other, so that the temperature of the tire side portion 70 increases. It cannot be suppressed.

  In the second embodiment, it is preferable that the center position C of the interval P overlaps with the thickest position t1. According to this, compared with the case where the center position C of the space | interval P remove | deviates from the position which overlaps with the thickest position t1, heat dissipation of the thickest position t1 of the reinforcement rubber 30 considered that temperature tends to rise is accelerated | stimulated. For this reason, the temperature rise of the thickest position t1 of the reinforcement rubber 30 can be further effectively suppressed, and the temperature rise of the tire side portion 70 can be further effectively suppressed.

[Other Embodiments]
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, examples and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. In the first embodiment, the protrusion 100 has been described as being provided in the maximum curvature region MR. However, the present invention is not limited to this, and it is needless to say that the protrusion 100 may be provided in the reinforcing rubber arrangement region.

  In 1st Embodiment, although the protrusion part 100 demonstrated as what extended continuously along a tire peripheral direction perimeter, it is not limited to this, Plurality is extended intermittently in a tire peripheral direction. You may do it.

  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 1,1A ... Run flat tire, 10 ... Bead part, 11 ... Bead core, 13 ... Bead filler, 20 ... Carcass, 30 ... Reinforcement rubber, 31 ... Tire radial direction outer end, 33 ... Tire radial direction inner end, 35 ... Bending 40, inner liner, 50 ... belt, 60 ... tread, 70 ... tire side portion, 71 ... outer side surface, 100, 100A ... projection, 101 ... inner side surface, 101A ... inner projecting end, 101B ... inner bottom end, DESCRIPTION OF SYMBOLS 103 ... Outer surface, 103A ... Outer projecting end, 103B ... Outer bottom end, 105 ... Upper surface, 107 ... Projection position, 200 (200A-200E) ... Projection

Claims (8)

A run flat tire provided with a reinforcing rubber in the tire side portion that suppresses deformation of the tire side portion when the internal pressure is reduced,
Protruding portions that protrude from the outer side surface of the tire side portion toward the outer side in the tread width direction,
The protrusion extends in the tire circumferential direction and is provided in a reinforcing rubber arrangement region that is a region between a tire radial outer end of the reinforcing rubber and a tire radial inner end of the reinforcing rubber. Run flat tire. Comprising a carcass forming the skeleton of the run-flat tire,
2. The run flat tire according to claim 1, wherein the protrusion is provided in a maximum curvature region including a maximum curvature position where the curvature of the carcass is the largest in a cross section along the tread width direction of the run flat tire.   The protrusion is provided in a maximum thickness region including a thickest position where the thickness of the reinforcing rubber along the direction orthogonal to the carcass is the largest in a cross section along the tread width direction of the run flat tire. Item 3. The run flat tire according to Item 2.   The run-flat tire according to any one of claims 1 to 3, wherein the protrusion extends continuously along the tire circumferential direction. The length between the outer end in the tire radial direction of the reinforcing rubber and the inner end in the tire radial direction of the reinforcing rubber along the outer side surface of the tire side portion is a reinforcing rubber length S, and the tire diameter with reference to the maximum curvature position. When the outside in the direction is the plus side and the inside in the tire radial direction is the minus side,
The run-flat tire according to any one of claims 2 to 4, wherein the protrusion is provided within a range of + 0.2S to -0.2S. The height h of the protrusion from the outer surface is 0.5 mm to 7.0 mm, and
The run-flat tire according to any one of claims 1 to 5, wherein a width w in a tire radial direction of the protrusion is 1.0 mm to 5.0 mm. A plurality of the protrusions are provided in the tire radial direction,
The distance P between the central portions in the tire radial direction of the protrusions adjacent to each other, and the height h from the outer surface of the protrusions,
8 ≦ P / h ≦ 16
While satisfying
The distance P and the width w of the protrusion in the tire radial direction are:
1.0 ≦ (P−w) / w <P
The run flat tire according to any one of claims 1 to 4, which satisfies the following conditions. The length of the tire radial direction outer end of the reinforcing rubber and the tire radial inner end of the reinforcing rubber along the outer side surface of the tire side portion is defined as a reinforcing rubber length S, and the maximum curvature position is used as a reference. When the outer side in the tire radial direction is the positive side and the inner side in the tire radial direction is the negative side,
The run flat tire according to claim 7, wherein at least a part of the protrusion is provided within a range of + 0.15S to −0.15S.

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