JP2008302740A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of maintaining normal traveling performance and efficiently reducing the temperature of the tire. <P>SOLUTION: The pneumatic tire 1 is provided with turbulence generation projections 17 for generating turbulence on the tire surface 15. The turbulence generation projection 17 is at least provided with a front portion (front face 17C) positioned in the front side with respect to the tire rotating direction from a projection centerline and with a rear portion (rear face 17D) positioned in the rear side with respect to the tire rotating direction from the projection centerline. A front angle (θ1) between the front portion and the tire surface 15 and a rear angle (θ2) between the rear portion and the tire surface 15 are set below 90°, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire including a turbulent flow generation projection that generates turbulent flow.

  In general, an increase in tire temperature in a pneumatic tire promotes a change over time such as a change in material properties, or causes a damage of a tread portion at high speed running, which is not preferable from the viewpoint of durability. . To improve durability, especially in off-the-road radial tires (ORR), truck / bus radial tires (TBR), and run-flat tires during puncture (running at an internal pressure of 0 kPa), which are used under heavy loads Reducing tire temperature has become a major issue.

  For example, in a run-flat tire having a crescent-shaped sidewall reinforcement layer, deformation in the tire radial direction concentrates on the sidewall reinforcement layer during puncturing, and the sidewall reinforcement layer reaches a very high temperature, resulting in durability. Has a great influence.

As a technology for reducing the tire temperature in such a pneumatic tire, a technology for providing a reinforcing member that reduces or suppresses distortion of each component of the pneumatic tire (particularly, a carcass layer or a bead portion located in a sidewall portion). Is disclosed (for example, see Patent Document 1).
JP 2006-76431 A (pages 1 to 4, FIGS. 3, 5, 10, 11, 12)

  However, in the conventional pneumatic tire described above, the provision of the reinforcing member may cause an unintentional new failure such as an increase in tire weight or separation (peeling) at the reinforcing member. There is a problem that the normal running performance such as the riding comfort is deteriorated. In particular, in a run-flat tire, there is a concern that the vertical spring (elasticity in the tire longitudinal direction) during normal internal pressure traveling is increased and the normal traveling performance is deteriorated, and a method that does not impair this normal traveling performance has been demanded.

  Therefore, the present invention has been made in view of such a situation, and an object thereof is to provide a pneumatic tire capable of maintaining normal running performance and efficiently reducing the tire temperature.

  Based on the situation described above, the inventors analyzed the efficient reduction of tire temperature. As a result, it has been found that increasing the velocity gradient (speed) of the fluid generated around the pneumatic tire as the pneumatic tire rotates increases the heat dissipation rate of the tire temperature.

  Therefore, the present invention has the following features. First, the invention according to the first aspect of the present invention is a pneumatic tire provided with a turbulent flow generation protrusion on a tire surface for generating turbulent flow, wherein the turbulent flow generation protrusion is a turbulent flow generation protrusion tire. A front portion that passes through the center of the rotation direction width and that is located on the front side with respect to the tire rotation direction with respect to the protrusion center line perpendicular to the tire rotation direction; A front angle (θ1) that is an angle formed by the front portion and the tire surface, and a rear angle (θ2) that is an angle formed by the rear portion and the tire surface is less than 90 degrees. It is a summary.

  The tire surface includes a tire outer surface (for example, an outer surface of a tread portion or a sidewall portion) and a tire inner surface (for example, an inner surface of an inner liner).

  According to such a feature, when the forward angle (θ1) and the backward angle (θ2) are less than 90 degrees, the flow of fluid colliding with the front portion can increase the pressure at the front portion, and turbulence is generated. It is possible to accelerate the fluid around the projection.

  In addition, the pressure can be increased on the front side of the turbulent flow generation protrusion with respect to the tire rotation direction of the turbulent flow generation protrusion, and the flow of fluid passing around the turbulent flow generation protrusion is accelerated as the pressure increases. (That is, the heat dissipation rate of the tire temperature can be increased). As a result, normal running performance can be maintained and tire temperature can be efficiently reduced without causing a new failure.

  According to another aspect of the invention, a protrusion radial direction length (D) which is a length between an innermost portion located on the innermost side in the tire radial direction and an outermost portion located on the outermost side in the tire radial direction on the protrusion centerline. ) Is 0.3 mm to 10 mm.

  According to such a feature, when the length (D) in the radial direction of the protrusion is 0.3 mm to 10 mm, it is possible to reduce the temperature rise at the root portion of the turbulent flow generation protrusion, and It becomes possible to further accelerate the flow of the fluid passing through the surroundings.

  The gist of the invention relating to other features is that the maximum protrusion height (H), which is the height from the tire surface to the maximum protrusion position that protrudes most with respect to the tire surface, is 0.3 mm to 10 mm. .

  According to this feature, when the maximum protrusion height (H) is 0.3 mm to 10 mm, the temperature rise at the root portion of the turbulent flow generating protrusion can be reduced, and the turbulent flow generating protrusion is surrounded by It is possible to further accelerate the flow of the fluid passing through the.

  According to another aspect of the invention, the protrusion for generating a turbulent flow is a rear protrusion that protrudes toward the rear side in the tire rotation direction at a rear portion positioned rearward of the tire rotation direction with respect to the protrusion center line. The gist of the invention is to include at least one of a rear recess that is recessed in the tire rotation direction.

  According to such a feature, since the turbulent flow generation projection includes the rear convex portion, the fluid that flows backward can be smoothly returned to the main flow, so that the tire temperature can be efficiently reduced.

  In addition, since the turbulent flow generation projection has a rear recess, the volume of the turbulent flow generation projection is reduced, and the distance between the root portion of the turbulent flow generation projection and the tire surface is shortened. It is possible to reduce the temperature rise at the base portion of the projection.

  Furthermore, since the turbulent flow generation projection includes the rear convex portion and the rear concave portion, not only can the flow of the fluid passing around the turbulent flow generation projection be accelerated, but also the root portion of the turbulent flow generation projection. It is possible to reduce the temperature rise of the tire, and the tire temperature can be further efficiently reduced.

  The invention according to other features includes an inner angle (θ3) that is an angle formed between an innermost portion in the tire radial direction and a tire surface, and an outer portion and a tire surface that are positioned on the outermost side in the tire radial direction. The gist is that the outer angle (θ4), which is the angle between the two, is 45 to 135 degrees.

  According to this feature, when the inner angle (θ3) and the outer angle (θ4) are 45 degrees to 135 degrees, when the fluid collides with the front part and spreads around the turbulent flow generation projection, It is possible to reliably accelerate the flow of fluid that peels (spreads) around the flow generation projection.

  The invention according to other features includes a front maximum angle (θ5) that is an angle formed by an intersection position of the front portion and the tire surface and a maximum protrusion position that protrudes most with respect to the tire surface, and the tire more than the protrusion center line. The gist is that the rear maximum angle (θ6), which is an angle formed by the crossing position of the rear portion and the tire surface located on the rear side with respect to the rotation direction and the maximum protruding position, is 45 to 135 degrees.

  The invention according to another feature is the inner maximum angle (θ7), which is an angle formed by the intersection between the innermost portion positioned in the tire radial direction and the tire surface and the maximum protruding position that protrudes most with respect to the tire surface. The outer maximum angle (θ8), which is an angle formed by the intersection between the outermost portion located on the outermost side in the tire radial direction and the tire surface and the maximum protruding position, is 45 to 135 degrees. To do.

  Another aspect of the invention is summarized in that the turbulent flow generation projection is provided on the sidewall portion.

  According to such a feature, the protrusion for generating a turbulent flow is provided on the sidewall portion, and therefore, the portion where the temperature rises sharply due to bending or the like (for example, in the case of a run flat tire, the sidewall reinforcement in the puncture state). The tire temperature can be efficiently reduced at the outside of the layer, and the durability can be improved.

  Another aspect of the invention is characterized in that the turbulent flow generation projection is provided on at least one of the bottom surface and the side surface of the groove formed in the tread portion.

  According to this feature, the turbulent flow generation protrusion is provided on at least one of the bottom surface and the side surface of the groove formed in the tread portion, so that the separation (peeling) and the crack are easily generated at the end of the belt layer. The tire temperature can be reduced in the vicinity of the groove formed in the nearest tread portion, and the durability can be improved.

  Another aspect of the invention is summarized in that the turbulent flow generation protrusion is provided on the inner surface of the tire.

  According to this feature, the provision of the turbulent flow generation projection on the tire inner surface makes it possible to reduce the temperature of the tire inner surface, particularly the tire inner surface in a punctured state, and improve durability. it can.

  The gist of the invention according to another feature is that it further includes a crescent-shaped side wall reinforcing layer that reinforces the side wall portion in the cross section in the tread width direction.

  According to this feature, by further including the sidewall reinforcing layer, the tire temperature at the sidewall portion where the temperature rise is considered to be severe can be reduced, and the durability can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, while maintaining normal driving | running | working performance, the pneumatic tire which can reduce tire temperature efficiently can be provided.

  Next, an example of a pneumatic tire according to the present invention will be described with reference to the drawings. 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.

[First Embodiment]
(Composition of pneumatic tire)
First, the configuration of the pneumatic tire according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a partially exploded perspective view of the pneumatic tire according to the first embodiment, and FIG. 2 is a cross-sectional view in the tread width direction of the pneumatic tire according to the first embodiment.

  As shown in FIGS. 1 and 2, the pneumatic tire 1 has a pair of bead portions 3 including at least a bead core 3a and a bead filler 3b. The pneumatic tire 1 has a carcass layer 5 that is folded around the bead core 3a from the inner side in the tread width direction toward the outer side in the tread width direction and extends in a toroidal shape via the sidewall portion SW.

  On the inner side in the tread width direction of the carcass layer 5, a crescent-shaped side wall reinforcing layer 7 that reinforces the sidewall portion SW in the cross section in the tread width direction is provided. An inner liner 9, which is a highly airtight rubber layer corresponding to a tube, is provided on the inner side in the tread width direction of the sidewall reinforcing layer 7.

  On the outer side in the tire radial direction of the carcass layer 5, the first belt layer 11a and the second belt layer 11b in which the cords are inclined with respect to the tire circumferential direction, and the cords are arranged substantially parallel to the tire circumferential direction. A belt layer 11 constituted by a circumferential belt layer 11c is provided.

  A tread portion 13 in contact with the road surface is provided on the outer side of the belt layer 11 in the tire radial direction. Further, the sidewall portion SW is provided with a plurality of turbulent flow generation projections 17 protruding from the tire surface 15 (surface of the sidewall portion SW) and generating turbulent flow along the tire circumferential direction. The plurality of turbulent flow generation projections 17 can be arranged at arbitrary intervals.

(Configuration of the turbulent flow generation projection 17)
Next, the configuration of the turbulent flow generation projection 17 will be described with reference to FIGS. FIG. 3 is a perspective view showing the turbulent flow generation projection according to the first embodiment, and FIG. 4A is a top view showing the turbulent flow generation projection according to the first embodiment (FIG. FIG. 4B is a cross-sectional view (a cross-sectional view taken along line BB in FIG. 3) showing the tire radial projection of the turbulent flow generation projection according to the first embodiment. FIG. 4C is a front view (viewed in the direction of the arrow C in FIG. 3) showing the tire rotation direction view of the turbulent flow generation projection according to the first embodiment.

  As shown in FIGS. 3 and 4, the turbulent flow generation projection 17 includes an inner side surface 17A located on the innermost side in the tire radial direction, an outer side surface 17B located on the outermost side in the tire radial direction, and a tire rotating direction. On the other hand, the front surface 17C is located on the foremost side, the rear surface 17D is located on the rearmost side with respect to the tire rotation direction, and the projecting surface 17E projects most on the tire surface 15.

  The front surface 17C is located at a front portion that is located on the front side with respect to the tire rotation direction with respect to the projection center line CL that passes through the center of the tire rotation direction width of the projection 17 for generating turbulent flow and is perpendicular to the tire rotation direction. ing. Further, the rear surface 17D is located at a rear portion located on the rear side with respect to the tire rotation direction with respect to the projection center line CL.

  In the present embodiment, the inner side surface 17A constitutes an inner portion, and the outer side surface 17B constitutes an outer portion. The front surface 17C constitutes a front portion, the rear surface 17D constitutes a rear portion, and the projecting surface 17E constitutes a projecting portion.

  As shown in FIG. 4A, in the turbulent flow generation projection 17, the inner side surface 17A and the outer side surface 17B are in contact with the projection center line CL when the turbulent flow generation projection 17 is viewed from above. The front surface 17C and the rear surface 17D are provided substantially parallel to the projection center line CL. That is, in the turbulent flow generation projection 17, the inner surface 17 </ b> A, the outer surface 17 </ b> B, the front surface 17 </ b> C, and the rear surface 17 </ b> D are formed in a parallelogram shape (all are flat) when viewed from above.

  In addition, as shown in FIG. 4B, the turbulent flow generation projection 17 has a front surface 17C (front portion) in the tire radial direction as viewed from the tire radial direction. A front angle (θ1) that is an angle formed by the tire surface 15 and a rear angle (θ2) that is an angle formed by the rear surface 17D (rear portion) and the tire surface 15 are set to be less than 90 degrees. In particular, the front angle (θ1) and the rear angle (θ2) are preferably 45 degrees or more and less than 90 degrees.

  In the present embodiment, as shown in FIGS. 3 and 4, the turbulent flow generation projection 17 has a front angle (θ1) and a rear angle (θ2) of 80 degrees, and the bottom surface (tire surface) in the tire radial direction view. The bottom surface of the turbulent flow generation projection 17 in contact with 15 is formed in a trapezoid shape narrower than the projecting surface 17E.

  When the front angle (θ1) and the rear angle (θ2) are 90 degrees or more, the pressure on the front side T (see FIG. 5A) of the turbulent flow generation projection 17 is difficult to increase, The flow of fluid passing through the periphery of the protrusion 17 (for example, the inner surface 17A, the outer surface 17B, and the protruding surface 17E) becomes slow, and the tire temperature cannot be reduced efficiently. If the front angle (θ1) and the rear angle (θ2) are less than 90 degrees, the fluid flow is restricted on the front side T of the turbulent flow generation projection 17 and passes around the turbulent flow generation projection 17. In some cases, the flow of fluid becomes slow, and the tire temperature cannot be reduced efficiently.

  Further, in the turbulent flow generation projection 17, as shown in FIG. 4C, when the turbulent flow generation projection 17 is viewed from the front side in the tire rotation direction, the protruding surface 17E is the tire rotation direction. It is provided substantially parallel to the surface 15. That is, the turbulent flow generation projection 17 is formed in a parallelogram shape when viewed in the tire rotation direction.

  On the protrusion center line CL, the protrusion radial direction length (D), which is the maximum length between the inner surface 17A and the outer surface 17B, is set to 0.3 mm to 10 mm. In particular, the length (D) in the protrusion radial direction is such that the temperature of the root portion T1 of the turbulent flow generation protrusion 17 (see FIG. 5A) can easily escape to the tire surface 15 and the turbulent flow generation protrusion 17 In order to make it easy to change the flow of the fluid passing through, it is preferably 0.5 mm to 5 mm.

  If the projection radial length (D) is smaller than 0.3 mm, it is insufficient to change the flow of fluid passing around the turbulent flow generation projection 17 and efficiently reduces the tire temperature. It may not be possible to Further, if the length in the projection radial direction (D) is larger than 10 mm, it is insufficient to reduce the temperature rise of the root portion T1 of the turbulent flow generation projection 17, and the tire temperature can be efficiently reduced. There are cases where it is not possible.

  As shown in FIGS. 4B and 4C, the maximum protrusion height that is the height from the tire surface 15 to the maximum protrusion position that protrudes most with respect to the tire surface 15 (that is, the protrusion surface 17E). The length (H) is set to 0.3 mm to 10 mm. In particular, the maximum protrusion height (H) is such that the temperature of the root portion T1 (see FIG. 5A) of the turbulent flow generation projection 17 is easily released to the tire surface 15, and the turbulent flow generation projection 17 is surrounded by the periphery. In order to make it easy to change the flow of the fluid passing therethrough, it is preferably 0.5 mm to 5 mm.

  If the maximum protrusion height (H) is smaller than 0.3 mm, it is not sufficient to change the flow of fluid passing around the turbulent flow generation protrusion 17, and the tire temperature is efficiently reduced. It may not be possible. Further, if the maximum protrusion height (H) is larger than 10 mm, it is insufficient to reduce the temperature rise of the root portion T1 of the turbulent flow generation protrusion 17, and the tire temperature cannot be reduced efficiently. There is a case.

  As shown in FIG. 4C, the inner angle (θ3) that is the angle formed by the inner surface 17A and the tire surface 15 and the outer angle (θ4) that is the angle formed by the outer surface 17B and the tire surface 15 are 45 degrees to 135 degrees. In particular, the inner angle (θ3) and the outer angle (θ4) are preferably 70 to 110 degrees in order to efficiently reduce the tire temperature.

  When the inner angle (θ3) and the outer angle (θ4) are smaller than 45 degrees, the fluid flow is stopped on the tire surface 15 (on the heat radiation surface), and the fluid cannot be accelerated due to the pressure difference. There is. Further, if the inner angle (θ3) and the outer angle (θ4) are larger than 135 degrees, it is insufficient to change the flow of the fluid that passes around the turbulent flow generation projections 17, and the tire temperature is efficiently increased. In some cases, it cannot be reduced.

(Operations and effects according to the first embodiment)
According to the pneumatic tire 1 which concerns on 1st Embodiment demonstrated above, when the front angle ((theta) 1) and back angle ((theta) 2) are less than 90 degree | times, the fluid which collides with the front surface 17C (front part). By this flow, the pressure can be increased on the front surface 17C, and the fluid around the turbulent flow generation projection 17 can be accelerated.

  Further, the pressure can be increased on the front side (front surface 17C) of the turbulent flow generation projection 17 with respect to the tire rotation direction, and the flow of fluid passing around the turbulent flow generation projection 17 is accelerated as the pressure increases. (That is, increase the heat dissipation rate of the tire temperature). As a result, normal running performance can be maintained and tire temperature can be efficiently reduced without causing a new failure.

  Specifically, as shown in FIG. 5, the fluid (hereinafter referred to as main flow S <b> 1) that has been in contact with the tire surface 15 (sidewall portion SW) with the rotation of the pneumatic tire 1 is a turbulent flow generation projection 17. Further, it is peeled off from the sidewall portion SW, gets over the front edge E of the turbulent flow generation projection 17 and accelerates toward the rear side (that is, the rear side) with respect to the tire rotation direction.

  When the front angle (θ1) and the rear angle (θ2) are less than 90 degrees, the main stream S1 is peeled off from the apex at which one front surface 17C and the other front surface 17C intersect before overcoming the front edge E. Therefore, the vehicle will accelerate when it gets over the front edge E.

  The accelerated main flow S1 flows in the vertical direction with respect to the tire surface 15 on the back side of the rear surface 17D. At this time, the fluid S3 flowing in the portion (area) where the fluid flow stays takes away the heat staying on the back side of the rear surface 17D and flows again into the main flow S1.

  The main flow S1 gets over the front edge E and accelerates, and the fluid S3 loses heat and flows again into the main flow S1, so that the tire temperature can be reduced over a wide range. In particular, the root of the turbulent flow generation projection 17 can be reduced. It is possible to reduce the portion T1 and the region T2 where the main flow S1 contacts in the vertical direction.

  Further, when the length (D) in the protrusion radial direction is 0.3 mm to 10 mm and the maximum height (H) of the protrusion is 0.3 mm to 10 mm, the root portion T1 of the protrusion 17 for generating turbulent flow is reduced. The temperature rise can be reduced, and the flow of the fluid passing around the turbulent flow generation projection 17 can be further accelerated.

  Further, when the front angle (θ1) and the rear angle (θ2) are 45 degrees to 135 degrees, the pressure of the front surface 17C can be increased by the flow of the fluid colliding with the front surface 17C, and turbulent flow is generated. It is possible to further accelerate the flow of the fluid passing around the projection 17.

  Furthermore, the side wall reinforcement layer 7 is provided, and the turbulent flow generation projection is provided on the side wall portion, so that the temperature rises greatly due to bending or the like (for example, side wall reinforcement in a puncture state). The tire temperature can be efficiently reduced at the outside of the layer, and the durability can be improved.

(Modification 1)
Although the turbulent flow generation projection 17 according to the first embodiment described above has been described as being formed in a trapezoidal shape whose bottom surface is narrower than the projecting surface 17E when viewed in the tire radial direction (BB cross-sectional view). The following modifications may be made. The same parts as those of the turbulent flow generation projection 17 according to the first embodiment described above are denoted by the same reference numerals, and different parts will be mainly described.

  6A is a perspective view showing a turbulent flow generation projection according to Modification Example 1. FIG. 6B is a cross-sectional view of the turbulent flow generation projection according to Modification Example 1 as seen in the tire radial direction. (B arrow view of FIG. 6).

  As shown in FIG. 6, the turbulent flow generation projection 17 includes an inner side surface 17A (inner side portion), an outer side surface 17B (outer side portion), and a protruding surface 17E (projecting portion).

  Specifically, in the turbulent flow generation projection 17, when viewed in the tire radial direction, a front angle (θ1) that is an angle formed by the front portion 19 </ b> A and the tire surface 15, and a rear portion 19 </ b> B and the tire surface 15 are formed. The rear angle (θ2), which is an angle, is set to be less than 90 degrees. Note that the front angle (θ1) and the rear angle (θ2) according to the modified example 1 indicate angles at a portion where the turbulent flow generation projection 17 rises from the tire surface 15.

  Further, the turbulent flow generation projection 17 is formed in a semispherical shape as viewed in the tire radial direction. That is, the protruding surface 17E is curved on the tire surface 15.

  As shown in FIG. 6 (b), the maximum protrusion height (H) that is the height from the tire surface 15 to the maximum protrusion position 21 that protrudes most with respect to the tire surface 15 is 0.3 mm to 10 mm. Is set. In particular, the maximum protrusion height (H) is preferably 0.5 mm to 5 mm.

  On the protrusion center line CL, the protrusion radial direction length (D) is set to 0.3 mm to 10 mm. In particular, the protrusion radial direction length (D) is preferably 0.5 mm to 5 mm.

  Further, the front protrusion angle (θ5) and the rear protrusion angle (θ6) are set to 45 degrees to 135 degrees. In particular, the front protrusion angle (θ5) and the rear protrusion angle (θ6) are preferably 70 degrees to 110 degrees in order to efficiently reduce the tire temperature.

  Here, the forward protrusion angle (θ5) is an angle formed by the intersection position 23 of the front portion 19A and the tire surface 15 and the maximum protrusion position 21. Further, the rearward projecting angle (θ6) is defined as the intersection between the rearward portion 19B located on the rear side of the tire rotation direction with respect to the tire rotation direction with respect to the projecting center line CL on the projecting surface 17E, and the maximum projecting position 21. It is an angle to make.

  If the front protrusion angle (θ5) and the rear protrusion angle (θ6) are smaller than 45 degrees, the fluid flow is stopped on the tire surface 15 (on the heat radiation surface), and the fluid flow due to the pressure difference is accelerated. It may not be possible. Further, if the front protrusion angle (θ5) and the rear protrusion angle (θ6) are larger than 135 degrees, it is insufficient to change the flow of the fluid passing around the turbulent flow generation projection 17 and the tire temperature is reduced. In some cases, it cannot be reduced efficiently.

  According to the pneumatic tire 1 according to the first modified example, the flow of the fluid passing around the turbulent flow generation projection 17 can be smoothly accelerated, and the tire temperature can be efficiently reduced. it can.

  In addition, since the front protrusion angle (θ5) and the rear protrusion angle (θ6) are 45 ° to 135 °, the pressure near the front portion 19A is caused by the flow of fluid colliding with the front portion 19A (the front side of the protruding surface 17E). And the flow of fluid passing around the turbulent flow generation projection 17 can be further accelerated.

(Modification 2)
The turbulent flow generation projection 17 according to the first embodiment described above has been described as being formed in a parallelogram shape as viewed in the tire rotation direction (viewed from the arrow C), but is modified as follows. Also good. The same parts as those of the turbulent flow generation projection 17 according to the first embodiment described above are denoted by the same reference numerals, and different parts will be mainly described.

  FIG. 7A is a perspective view showing a turbulent flow generation projection according to Modification Example 2, and FIG. 7B is a cross-sectional view showing the turbulent flow generation projection according to Modification Example 1 as viewed in the tire radial direction. FIG. 7C is a front view of the turbulent flow generation projection according to Modification 1 as viewed in the tire rotation direction (viewed in the direction of arrow C in FIG. 7). .

  As shown in FIG. 7, the turbulent flow generation projection 17 includes an inner side surface 17A (inner side portion), an outer side surface 17B (outer side portion), and a projecting surface 17E (projection portion).

  Specifically, the turbulent flow generation projection 17 is formed in a semispherical shape as viewed in the tire rotation direction. That is, the protruding surface 17E is curved on the tire surface 15. Even in this case, in the turbulent flow generation projection 17, the front angle (θ1) and the rear angle (θ2) are set to be less than 90 degrees as viewed in the tire radial direction.

  As shown in FIGS. 7B and 7C, the maximum protrusion height (H), which is the height from the tire surface 15 to the maximum protrusion position 27 that protrudes most with respect to the tire surface 15, is It is set at 0.3 mm to 10 mm. In particular, the maximum protrusion height (H) is preferably 0.5 mm to 5 mm.

  On the protrusion center line CL, the protrusion radial direction length (D) is set to 0.3 mm to 10 mm. In particular, the protrusion radial direction length (D) is preferably 0.5 mm to 5 mm.

  Further, the inner protrusion angle (θ7) and the outer maximum angle (θ8) are set at 45 to 135 degrees. In particular, the inner protrusion angle (θ7) and the outer maximum angle (θ8) are preferably 70 degrees to 110 degrees in order to efficiently reduce the tire temperature.

  Here, the inner protrusion angle (θ7) is an angle formed by the intersection portion 29 of the innermost portion 19C located at the innermost side in the tire radial direction and the tire surface 15 and the maximum protrusion position 27. Further, the maximum outer angle (θ8) is an angle formed between the outermost portion 19D positioned on the outermost side in the tire radial direction and the intersection position 31 of the tire surface 15 and the maximum protrusion position 27.

  If the inner protrusion angle (θ7) and the outer maximum angle (θ8) are smaller than 45 degrees, the fluid flow is stopped on the tire surface 15 (on the heat radiation surface), and the fluid flow due to the pressure difference is accelerated. It may not be possible. Further, if the inner protrusion angle (θ7) and the outer maximum angle (θ8) are larger than 135 degrees, it is insufficient to change the flow of the fluid passing around the turbulent flow generation projection 17, and the tire temperature is reduced. In some cases, it cannot be reduced efficiently.

  Here, the turbulent flow generation projection 17 has been described as being formed in a semi-spherical shape as viewed in the tire rotation direction, but is not limited to this, for example, as shown in FIG. In addition, it may be formed in a triangular shape when viewed in the tire rotation direction, and as shown in FIG. 8B, the bottom surface may be formed in a trapezoidal shape wider than the protruding surface 17E when viewed in the tire rotation direction. As shown in FIG. 8C, the bottom surface may be formed in a trapezoidal shape narrower than the projecting surface 17E when viewed in the tire rotation direction.

  According to the pneumatic tire 1 according to the second modified example, the fluid flow passing around the turbulent flow generation projection 17 can be smoothly accelerated, and the tire temperature can be efficiently reduced. .

  Further, since the inner protrusion angle (θ7) and the outer maximum angle (θ8) are 45 degrees to 135 degrees, when the fluid collides with the front surface 17C and spreads around the turbulent flow generation projection 17, It is possible to reliably accelerate the flow of fluid that peels (spreads) around the flow generation projection 17.

(Modification 3)
The front surface 17C constituting the turbulent flow generation projection 17 according to the first embodiment described above is formed by a front surface 17C located at the front portion being formed substantially parallel to the projection center line CL. However, the following modifications may be made. The same portions as those of the turbulent flow generation projection 17 according to the first embodiment described above are denoted by the same reference numerals, and different portions will be mainly described.

  FIG. 9A to FIG. 9G are top views showing turbulent flow generation projections according to the third modification. As shown in FIG. 9A, the turbulent flow generation projection 17 includes a front convex portion 17C-1 that projects toward the front side in the tire rotation direction when the projection is viewed from above.

  As shown in FIG. 9A, the turbulent flow generation projection 17 may be provided with a curved front surface 17C. As shown in FIG. 9B, the front surface 17C has a projection center line CL. It may be provided to be inclined.

  The turbulent flow generation projection 17 may have two front surfaces 17C as shown in FIG. In this case, the two front surfaces 17C are not limited to having the same size, and may of course have different sizes.

  Further, as shown in FIGS. 9D to 9G, the turbulent flow generation projections 17 are provided on the front projections 17C-1 at a plurality of locations and on the rear side in the tire rotation direction in the top view of the projections. You may provide the front recessed part 17C-2 of the several places dented toward. In this case, the front convex portion 17C-1 and the front concave portion 17C-2 may be provided in a straight line shape or may be provided in a curved shape.

  According to the pneumatic tire 1 according to the third modified example, the flow of fluid passing around the turbulent flow generation projection 17 can be smoothly accelerated, and the tire temperature can be efficiently reduced. it can.

(Modification 4)
The turbulent flow generation projection 17 according to the first embodiment described above has been described on the assumption that the rear surface 17D located in the rear portion is formed substantially parallel to the projection center line CL, but is deformed as follows. May be. The same parts as those of the turbulent flow generation projection 17 according to the first embodiment described above are denoted by the same reference numerals, and different parts will be mainly described.

  FIG. 10A to FIG. 10G are top views showing turbulent flow generation projections according to Modification 4. FIG. As shown in FIG. 10A, the turbulent flow generation projection 17 includes a rear projection 17D-1 that protrudes toward the rear side in the tire rotation direction when the projection is viewed from above.

  As shown in FIG. 10A, the turbulent flow generation projection 17 may be provided with a curved rear surface 17D. As shown in FIG. 10B, the rear surface 17C has a projection center line CL. It may be provided to be inclined.

  Further, the turbulent flow generation projection 17 may have two rear surfaces 17D as shown in FIG. In this case, the two rear surfaces 17D are not limited to having the same size, and may of course have different sizes.

  Further, as shown in FIGS. 10 (d) to 10 (g), the turbulent flow generation projections 17 are provided on the rear projections 17D-1 at a plurality of locations and on the rear side in the tire rotation direction in the top view of the projections. You may provide the back recessed part 17D-2 of the several places dented toward. In this case, the rear protrusion 17D-1 and the rear recess 17D-2 may be provided in a straight line shape or may be provided in a curved shape.

  According to the pneumatic tire 1 according to the modified example 4 as described above, the turbulent flow generation projection 17 includes the rear convex portion 17D-1, so that the fluid flowing backward can be smoothly returned to the mainstream. The tire temperature can be efficiently reduced.

  Further, since the turbulent flow generation projection 17 includes the rear concave portion 17D-2, the volume of the turbulent flow generation projection 17 is reduced, and the distance between the root portion of the turbulent flow generation projection 17 and the tire surface 15 is increased. Therefore, the temperature rise at the base portion of the turbulent flow generation projection 17 can be reduced.

  Furthermore, not only can the turbulent flow generation projection 17 include the rear projection 17D-1 and the rear recess 17D-2 to accelerate the flow of the fluid that passes around the turbulent flow generation projection 17, It is also possible to reduce the temperature rise at the base portion of the turbulent flow generation projection 17, and the tire temperature can be more efficiently reduced.

[Second Embodiment]
Next, the configuration of the pneumatic tire according to the second embodiment will be described with reference to FIG. FIG. 11 is a cross-sectional view in the tread width direction of the pneumatic tire according to the second embodiment. The same parts as those of the pneumatic tire 1 according to the first embodiment described above are denoted by the same reference numerals, and different parts will be mainly described.

  As shown in FIG. 11, the groove 13A formed in the tread portion 13 is provided with a plurality of turbulent flow generation projections 17 that protrude from the tire surface 15 (the surface of the groove 13A) and generate turbulent flow. The plurality of turbulent flow generation projections 17 can be arranged at arbitrary intervals.

  As shown in FIG. 11A, the turbulent flow generation projection is provided on the bottom surface 13a of the groove 13A. The turbulent flow generation projection 17 is not necessarily provided on the bottom surface 13a of the groove 13A. For example, as illustrated in FIG. 11B, the turbulent flow generation projection 17 may be provided on the side surface 13b of the groove. As long as it is provided on at least one of the bottom surface 13a and the side surface 13b.

(Operations and effects according to the second embodiment)
According to the pneumatic tire 1 according to the second embodiment described above, the turbulent flow generation projection 17 is provided on at least one of the bottom surface 13a and the side surface 13b of the groove 13A formed in the tread portion 13. This makes it possible to reduce the tire temperature in the vicinity of the groove 13A formed in the tread portion 13 closest to the end portion of the belt layer 11 where separation (peeling) and cracks are likely to occur, and to improve durability. it can.

[Third Embodiment]
Next, the configuration of the pneumatic tire according to the third embodiment will be described with reference to FIG. FIG. 12 is a cross-sectional view in the tread width direction of the pneumatic tire according to the third embodiment. In addition, the same code | symbol is attached | subjected to the same part as the pneumatic tire 1 which concerns on 1st Embodiment mentioned above, or 2nd Embodiment, and a different part is mainly demonstrated.

  As shown in FIG. 12, a plurality of turbulent flow generation projections 17 are provided on the inner side of the inner liner 9 in the tread width direction so as to protrude from the tire inner surface (inner liner 9) and generate turbulent flow. The plurality of turbulent flow generation projections 17 can be arranged at arbitrary intervals.

(Operations and effects according to the third embodiment)
According to the pneumatic tire 1 according to the third embodiment described above, the temperature of the tire inner surface, particularly the tire inner surface in a puncture state, is reduced by providing the turbulent flow generation projection 17 on the tire inner surface. It is possible to improve the durability.

  Specifically, when the pneumatic tire 1 is in a punctured state, heat exchange is performed between the fluid inside the tire (inside air) and the fluid outside the tire (outside air) through a hole formed in the pneumatic tire 1. At this time, by providing the turbulent flow generation projections 17 on the inner surface of the tire, it becomes possible to accelerate the fluid inside the tire and to perform heat exchange smoothly, thereby reducing the temperature of the inner surface of the tire in a punctured state. It becomes possible.

  In particular, in a pneumatic tire (run flat tire) provided with the sidewall reinforcement layer 7, the temperature inside the tire becomes higher in a punctured state than a tire without the sidewall reinforcement layer 7. For this reason, by providing the turbulent flow generation projection 17 on the inner surface of the tire, the temperature inside the tire can be reduced and the durability can be improved.

[Other embodiments]
As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention.

  Specifically, the pneumatic tire 1 has been described as having a sidewall reinforcing layer 7 (that is, a run-flat tire), but is not limited thereto, and has the sidewall reinforcing layer 7. Of course, it may be an off-the-road radial tire (ORR) or a truck / bus radial tire (TBR).

  The turbulent flow generation projection 17 can be combined with the various shapes described in the first to third embodiments and the first to fourth modifications, and at least the front angle (θ1) and the rear angle (θ2). ) Should be set to less than 90 degrees, and of course includes shapes not shown.

  Further, when the turbulent flow generation projection 17 is a flat surface (for example, the inner surface 17A and the outer surface 17B, the front surface 17C and the rear surface 17D, the protruding surface 17E and the bottom surface (tire surface 15)), The opposing surfaces do not necessarily have to be formed in parallel. For example, the opposing surfaces may be inclined (ascending / descending) from the front surface 17C toward the rear surface 17D, or the opposing surfaces may be asymmetric. .

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. 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.

  Next, in order to further clarify the effects of the present invention, the results of tests performed using pneumatic tires according to the following Comparative Examples 1 to 3 and Examples 1 to 21 will be described. In addition, this invention is not limited at all by these examples.

  Data on each pneumatic tire was measured under the following conditions.

・ Tire size: 285 / 50R20
・ Wheel size: 8JJ × 20
・ Internal pressure condition: 0 kPa (puncture state)
・ Load condition: 9.8kN
In order to perform a durability test of each pneumatic tire, a test tire A, a test tire B, and a test tire C were prepared as shown in Tables 1 to 3 below. The pneumatic tires according to Comparative Examples 1 to 3 do not have a turbulent flow generation projection. The pneumatic tires according to Examples 1 to 21 have turbulent flow generation protrusions, and as shown in Tables 1 to 3 below, the configuration (shape, protrusion radial direction length (D) of the turbulent flow generation protrusions ), The maximum projection height (H), etc.) are different.

<Durability>
Each pneumatic tire is mounted on a drum testing machine installed indoors and rolled at a constant speed (90 km / h), and the durability distance until the pneumatic tire according to Comparative Examples 1 to 3 fails is set to '100. The relative durability of other pneumatic tires was evaluated. In addition, durability is excellent, so that an index | exponent is large.

  As a result, as shown in Table 1, it was found that the pneumatic tires according to Examples 1 to 21 were superior in durability to the pneumatic tires according to Comparative Examples 1 to 3. In particular, as shown in FIG. 13, a pneumatic tire having a protrusion radial length (D) of 0.3 mm to 10 mm, or a protrusion maximum height (H) of 0.3 mm to 10 mm as shown in FIG. 14. It was found that the pneumatic tire is excellent in durability. Furthermore, it was also found that the protrusion radial direction length (D) and the protrusion maximum height (H) are preferably 0.5 mm to 5 mm.

1 is a partially exploded perspective view of a pneumatic tire according to a first embodiment. It is a tread width direction sectional view of the pneumatic tire concerning a 1st embodiment. It is a perspective view which shows the protrusion for turbulent flow generation which concerns on 1st Embodiment. It is an upper surface, a side surface, and a front view showing the turbulent flow generation projection according to the first embodiment. It is a figure for demonstrating the effect | action and effect of the protrusion for turbulent flow generation which concerns on 1st Embodiment. It is a perspective view and a side view showing a turbulent flow generation projection according to Modification 1. It is a perspective view and front view which show the protrusion for turbulent flow generation concerning the modification 2 (the 1). It is a front view which shows the protrusion for turbulent flow generation concerning the modification 2 (the 2). 10 is a top view showing a turbulent flow generation projection according to Modification 3. FIG. FIG. 10 is a top view showing a turbulent flow generation projection according to Modification 4. It is a tread width direction sectional view of the pneumatic tire concerning a 2nd embodiment. It is a tread width direction sectional view of the pneumatic tire concerning a 3rd embodiment. It is a graph which shows the durability of the pneumatic tire in an Example (the 1). It is a graph which shows the durability of the pneumatic tire in an Example (the 2).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 3 ... Bead part, 3a ... Bead core, 3b ... Bead filler, 5 ... Carcass layer, 7 ... Side wall reinforcement layer, 9 ... Inner liner, 11 ... Belt layer, 11a ... 1st belt layer, 11b ... second belt layer, 11c ... circumferential belt layer, 13 ... tread portion, 13A ... groove, 13a ... bottom surface, 13b ... side surface, 15 ... tire surface, 17 ... turbulent flow generating projection, 17A ... inner side surface, 17B ... Outer side surface, 17C ... front surface, 17C-1 ... front convex portion, 17C-2 ... front concave portion, 17D ... rear surface, 17D-1 ... rear convex portion, 17D-2 ... rear concave portion, 17E ... projecting surface, 19A ... Front part, 19B ... Back part, 19C ... Inner part, 19D ... Outer part, 21, 27 ... Maximum projecting position, 23, 25, 29, 31 ... Crossing position, CL ... Projection center line, SW ... Side wall part, E ... Square edge

Claims (11)

A pneumatic tire provided with a turbulent flow generation projection for generating turbulent flow on a tire surface,
The turbulent flow generation protrusion includes a front portion that passes through the center of the tire rotation direction width of the turbulent flow generation protrusion and is located on the front side with respect to the tire rotation direction with respect to the protrusion center line perpendicular to the tire rotation direction. And at least a rear portion located on the rear side with respect to the tire rotation direction with respect to the projection center line,
A forward angle (θ1) that is an angle formed by the front portion and the tire surface and a rear angle (θ2) that is an angle formed by the rear portion and the tire surface are less than 90 degrees. Pneumatic tires.   On the protrusion center line, the protrusion radial direction length (D), which is the length between the innermost part located in the innermost side in the tire radial direction and the outermost part located in the outermost side in the tire radial direction, is 0.3 mm to The pneumatic tire according to claim 1, wherein the pneumatic tire is 10 mm.   The protrusion maximum height (H), which is the height from the tire surface to the maximum protrusion position that protrudes most with respect to the tire surface, is 0.3 mm to 10 mm. 2. The pneumatic tire according to 2.   The turbulent flow generation projection includes at least one of a rear protrusion protruding toward the rear side in the tire rotation direction and a rear recess recessed toward the tire rotation direction in the rear portion. The pneumatic tire according to any one of claims 1 to 3.   An inner angle (θ3) that is an angle formed between the innermost portion in the tire radial direction and the tire surface, and an angle between the outer portion positioned in the outermost tire direction and the tire surface. The pneumatic tire according to any one of claims 1 to 4, wherein the certain outer angle (θ4) is 45 degrees to 135 degrees.   A front maximum angle (θ5) that is an angle formed between an intersection position of the front portion and the tire surface and a maximum protrusion position that protrudes most with respect to the tire surface; and an intersection position of the rear portion and the tire surface The pneumatic tire according to any one of claims 1 to 5, wherein a rear maximum angle (θ6) that is an angle formed with the maximum protruding position is 45 degrees to 135 degrees.   An inner maximum angle (θ7) that is an angle formed between an innermost portion located in the innermost side in the tire radial direction and the intersecting position of the tire surface and a maximum protruding position that protrudes most with respect to the tire surface, and the tire diameter The outer maximum angle (θ8), which is an angle formed between the outermost portion located in the outermost direction and the intersecting position of the tire surface and the maximum projecting position, is 45 to 135 degrees. The pneumatic tire according to any one of claims 1 to 6.   The pneumatic tire according to any one of claims 1 to 7, wherein the turbulent flow generation protrusion is provided on a sidewall portion.   The pneumatic tire according to any one of claims 1 to 8, wherein the turbulent flow generation protrusion is provided on at least one of a bottom surface and a side surface of a groove formed in the tread portion. .   The pneumatic tire according to claim 1, wherein the turbulent flow generation protrusion is provided on an inner surface of the tire.   The pneumatic tire according to any one of claims 1 to 10, further comprising a crescent-shaped sidewall reinforcing layer that reinforces the sidewall portion in a cross section in the tread width direction.

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