JP5385528B2 - Pneumatic tire - Google Patents

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. . Especially for 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) that are used under heavy loads, the durability of the tire is improved. Therefore, reducing the tire temperature has become a major issue.

For example, by increasing the thickness in the vicinity of the position where the bead portion contacts the rim flange to the outside in the tread width direction, and the thickened reinforcing portion is configured to wrap the rim flange (so-called rim guard). A pneumatic tire is disclosed that suppresses the deflection of the tire side portion (particularly, the bead portion) and reduces the tire temperature (see, for example, Patent Document 1).
JP 2006-76431 A (pages 2 to 5)

  However, in the conventional pneumatic tire described above, because the bead portion is thick, the temperature at the bead portion increases. There is a problem that the vicinity of the bead portion breaks due to the progress of cracks and the like.

  In particular, in heavy-duty tires, there is a concern about providing a reinforcing portion because of the large collapse during loading. However, in this heavy duty tire, even if the reinforcement portion is not provided in the bead portion, the bead portion is originally formed thicker than the other tire side portions, so that the temperature in the bead portion increases. As a result, not only the durability of the bead portion but also the durability of the tire decreases.

  Therefore, the present invention has been made in view of such a situation, and can reduce the tire temperature, particularly the temperature near the bead portion, and can improve the durability of the tire. The purpose is to provide.

  Based on the situation described above, the inventors analyzed the efficient reduction of tire temperature. As a result, by increasing the speed gradient (speed) of wind (running wind) generated from the front of the vehicle as the vehicle travels, and suppressing the temperature rise of the bead portion, the heat dissipation rate of the tire temperature can be increased. found.

  Therefore, the present invention has the following features. First, the invention according to the first aspect of the present invention is a pneumatic tire in which a turbulent flow generation protrusion for generating turbulent flow is provided on at least a part of a tire surface, wherein the turbulent flow generation protrusion is It is provided in the range from the maximum tire width position, which is the maximum width position, to the bead outer position, which is the position on the outer side in the tire radial direction of the bead portion in contact with the rim flange, and extends in a substantially arc shape along the tire circumferential direction. The gist is to exist.

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

  According to such a feature, the turbulent flow generation protrusion is provided in the range from the tire width maximum position to the bead outer position and extends in a substantially arc shape along the tire circumferential direction, so that the turbulent wind flows. When overcoming the generation projection, the pressure can be increased in front of the turbulent flow generation projection in the traveling direction, and with this pressure increase, the flow of the traveling wind passing through the turbulence generation projection is accelerated (that is, , Increase the heat dissipation rate of the tire temperature). With this accelerated traveling wind, the tire temperature, particularly the temperature near the bead portion can be reduced, and the durability of the tire can be improved.

  In another aspect of the invention, the height of the protrusion from the tire surface to the most protruding position of the turbulent flow generation protrusion is “h”, and the width of the lower side of the turbulent flow generation protrusion in the tire radial direction is “w”. In this case, the gist is to satisfy the relationship of 1.0 ≦ h / w ≦ 10.

  According to such a feature, by satisfying the relationship of 1.0 ≦ h / w ≦ 10 as described above, the traveling wind accelerated over this turbulent flow generation projection, and the tire temperature, particularly in the vicinity of the bead portion. The effect of reducing the temperature is increased.

  Another aspect of the invention is summarized in that the width (w) of the lower side in the tire radial direction of the turbulent flow generation projection is 2 to 10 mm.

  The gist of the invention relating to other features is that the projection height (h) from the tire surface to the most protruding position of the turbulent flow generation projection is 3 to 20 mm.

  The gist of the invention relating to other features is that the projection height (h) is 7.5 to 15 mm.

  In another aspect of the invention, in the cross section in the tread width direction, the distance from the innermost protrusion position that is the innermost radial direction of the turbulent flow generation protrusion to the outermost position of the rim that is the outermost radial direction of the rim flange The gist is that the protrusion rim distance (d) is 30 to 200 mm.

  Note that the protrusion rim distance (d) is a value measured when the normal internal pressure is filled with the normal rim mounted (including when a normal load is applied). The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, a standard rim for JATMA, “Design Rim” for TRA, or ETRTO Means "Measuring Rim". The above "regular internal pressure" is the air pressure specified by the above standard for each tire. The maximum air pressure described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" is the maximum air pressure for JATMA and TRA for TRA. If it is ETRTO, it is "INFLATION PRESSURE". The “regular load” is the load specified by the above standard for each tire. If it is JATMA, it is the maximum load capacity, and if it is TRA, it is the maximum described in the table “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”. If the value is ETRTO, it is "LOAD CAPACITY".

  The gist of the invention relating to other features is that, in the turbulent flow generation projection, the cross-sectional shape substantially orthogonal to the extending direction is formed in a substantially rectangular shape.

  Another aspect of the invention is characterized in that the turbulent flow generation projection has a substantially trapezoidal cross-sectional shape substantially orthogonal to the extending direction.

  Another aspect of the invention is characterized in that, in the turbulent flow generation projection, the cross-sectional shape substantially orthogonal to the extending direction is formed in a substantially triangular shape.

  Another aspect of the invention is characterized in that, in the turbulent flow generation projection, the cross-sectional shape substantially perpendicular to the extending direction is formed in a stepped shape having a step.

  Another aspect of the invention is characterized in that the turbulent flow generation projection is formed with a through-hole penetrating in a direction substantially orthogonal to the extending direction.

  According to another aspect of the invention, the height of the protrusion from the tire surface to the most protruding position of the turbulent flow generation protrusion is “h”, the pitch between the turbulent flow generation protrusions is “p”, and the turbulent flow generation protrusion When the width of the lower side in the tire radial direction is “w”, a relationship of 1.0 ≦ p / h ≦ 20.0 and 1.0 ≦ (p−w) /w≦100.0 The gist is to satisfy.

  Another aspect of the invention is summarized in that the protrusion inclination angle (θ) with respect to the tire circumferential direction of the turbulent flow generation protrusion is ± 20 degrees.

  The gist of another aspect of the invention is a heavy duty tire.

  According to the present invention, it is possible to provide a pneumatic tire that can reduce the tire temperature, particularly the temperature in the vicinity of the bead portion, and can improve the durability of the tire.

  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. FIG. 1 is a partially sectional perspective view showing a pneumatic tire according to the first embodiment, and FIG. 2 is a tread width direction sectional view showing the pneumatic tire according to the first embodiment. FIG. 3 is a partial side view (a view of arrow A in FIG. 2) showing the pneumatic tire according to the first embodiment. Note that the pneumatic tire according to the first embodiment is a heavy duty tire.

  As shown in FIGS. 1 to 3, the pneumatic tire 1 includes a pair of bead portions 3 including at least a bead core 3a and a bead filler 3b, and a carcass layer 5 that is folded back by the bead core 3a. Inside the carcass layer 5, an inner liner 7 which is a highly airtight rubber layer corresponding to a tube is provided.

  A tread portion 9 that is in contact with the road surface is provided outside the carcass layer 5 in the tire radial direction. A plurality of belt layers 11 that reinforce the tread portion 9 are provided between the carcass layer 5 and the tread portion 9. Furthermore, a turbulent flow generation projection 17 for generating turbulent flow is provided on the tire surface 15 (tire side portion surface) in the bead portion 3.

(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. 4 is a perspective view showing the turbulent flow generation projection according to the first embodiment.

  As shown in FIGS. 1 to 4, the turbulent flow generation projection 17 is located at a position on the outer side in the tire radial direction of the bead portion 3 in contact with the rim flange from the tire width maximum position (P1) that is the position of the tire maximum width TW. It is provided in a range R up to a certain bead outer position (P2).

  The turbulent flow generation projection 17 is formed by a single projection extending continuously in a substantially arc shape along the tire circumferential direction. Further, the turbulent flow generation projection 17 has a substantially quadrangular cross-sectional shape substantially orthogonal to the extending direction (that is, the substantially tire circumferential direction).

  Specifically, the turbulent flow generation protrusion 17 has a protrusion height “h” from the tire surface 15 to the most protruding position of the turbulent flow generation protrusion 17, and the turbulent flow generation protrusion 17 is lower in the tire radial direction. When the width of the side is “w”, the relationship of 1.0 ≦ h / w ≦ 10 is satisfied.

  If the value (h / w) of the ratio of the width (w) to the protrusion height (h) is smaller than 1.0, it is insufficient to accelerate the flow of the traveling wind over the turbulent flow generation protrusion 17. In some cases, the tire temperature, in particular, the temperature in the vicinity of the bead portion 3 cannot be efficiently reduced. On the other hand, if the value (h / w) of the ratio of the width (w) to the protrusion height (h) is larger than 10, it is not sufficient to reduce the temperature (heat storage temperature) in the turbulent flow generation protrusion 17. In some cases, the tire temperature cannot be reduced efficiently.

  The width (w) of the lower side of the turbulent flow generation projection 17 in the tire radial direction is preferably 2 to 10 mm.

  If the width (w) is smaller than 2 mm, the strength of the turbulent flow generation projection 17 becomes too weak, and the turbulent flow generation projection 17 is vibrated by the traveling wind, and the turbulent flow generation projection 17 The durability itself may be reduced. On the other hand, if the width (w) is larger than 10 mm, it is insufficient to reduce the temperature (heat storage temperature) in the turbulent flow generation projection 17 and the tire temperature may not be reduced efficiently. .

  Moreover, it is preferable that the projection height (h) from the tire surface 15 to the most protruding position of the turbulent flow generation projection 17 is 3 to 20 mm. In particular, the protrusion height (h) is preferably 7.5 to 15 mm.

  If the protrusion height (h) is smaller than 3 mm, it is insufficient for accelerating the flow of the traveling wind over the turbulent flow generation protrusion 17 and the tire temperature may not be reduced efficiently. is there. On the other hand, when the projection height (h) is larger than 20 mm, it is not sufficient to reduce the temperature (heat storage temperature) in the turbulent flow generation projection 17 and the strength of the turbulent flow generation projection 17 becomes weak. In some cases, the problems described above may occur.

  Further, in the cross section in the tread width direction, from the innermost protrusion position (P3) that is the innermost radial direction of the turbulent flow generation protrusion 17 to the outermost rim position (P4) that is the outermost radial direction of the rim flange 19 It is preferable that the protrusion rim distance (d) which is a distance of 30 to 200 mm.

  If the protrusion rim distance (d) is less than 30 mm, the traveling wind over the turbulent flow generation protrusion 17 flows to the rim flange 19 and the temperature in the vicinity of the bead portion 3 cannot be efficiently reduced. There is. On the other hand, if the protrusion rim distance (d) is larger than 200 mm, it is insufficient to reduce the temperature in the vicinity of the bead portion 3 that is originally thicker than other tire side portions, and the tire temperature is effectively reduced. In some cases, it cannot be reduced.

(Modification example according to the first embodiment)
The turbulent flow generation projection 17 according to the first embodiment described above has been described as being formed by a single projection extending continuously in a substantially arc shape, but even if it is modified as follows: Good. 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, and a different part is mainly demonstrated.

  FIG. 5 is a partial cross-sectional perspective view showing the modified pneumatic tire according to the first embodiment, and FIG. 6 is a partial view showing the modified pneumatic tire according to the first embodiment. It is a side view.

  As shown in FIGS. 5 and 6, the turbulent flow generation projection 17 is formed by a plurality of projections that are divided and extended in a substantially arc shape along the tire circumferential direction. The protrusion inclination angles (θ) of the turbulent flow generation protrusions 17 with respect to the tire circumferential direction are all set equal.

  Specifically, the protrusion inclination angle (θ) with respect to the tire circumferential direction of the turbulent flow generation protrusion 17 is set to ± 20 degrees. That is, in the turbulent flow generation projection 17, the inclination angle with respect to the tire radial direction is set to 70 to 90 degrees.

  When the protrusion inclination angle (θ) is larger than 20 degrees, the traveling wind generated from the front of the vehicle as the vehicle travels inclines and strikes against the turbulent flow generating protrusion 17. Compared with the case where the airflow flows substantially orthogonal to the turbulence 17, it is insufficient for accelerating the traveling wind over the turbulent flow generation projections 17, and the tire temperature may not be reduced efficiently.

  Here, the protrusions 17 for generating turbulent flow do not necessarily have to have the same protrusion inclination angle (θ) with respect to the tire circumferential direction. If the protrusion inclination angle (θ) is within the above range, different protrusion inclinations are possible. The angle (θ) may be used, and the directions may be different from each other.

(Operations and effects according to the first embodiment)
According to the pneumatic tire 1 according to the first embodiment described above, the turbulent flow generation projection 17 is provided in the range R from the tire width maximum position (P1) to the bead outer position (P2), and By extending in a substantially arc shape along the tire circumferential direction, when the traveling wind gets over the turbulent flow generation projection 17, the pressure can be increased on the front side of the turbulent flow generation projection 17 in the traveling direction, Along with this pressure increase, the flow of the traveling wind passing through the turbulent flow generation projection 17 can be accelerated (that is, the heat dissipation rate of the tire temperature can be increased). With this accelerated traveling wind, the tire temperature, particularly the temperature near the bead portion 3 can be reduced, and the durability of the tire can be improved.

  Specifically, as shown in FIG. 7, the traveling wind S <b> 1 generated from the front of the vehicle with the rotation of the pneumatic tire 1 is peeled from the tire surface 15 by the turbulent flow generation protrusion 17 and is then turbulent flow generation protrusion. The vehicle moves over the edge E on the front side of the vehicle 17 and accelerates toward the rear of the vehicle.

  The accelerated traveling wind S1 flows in a direction substantially perpendicular to the tire surface 15 behind the turbulent flow generation projection 17 (so-called downward flow). At this time, the fluid S2 flowing in the portion (region) where the flow of the traveling wind S1 stays takes the heat staying behind the turbulent flow generation projection 17 and flows again to the main flow S1.

  That is, the traveling wind S1 gets over the edge portion E on the front side of the turbulent flow generation projection 17 and accelerates, and the accelerated traveling wind S1 (downflow) and the fluid S2 take heat and flow again to the traveling wind S1. As a result, the tire temperature, particularly the temperature near the bead portion 3 can be reduced, and the durability of the tire can be improved.

  Further, by satisfying the relationship of 1.0 ≦ h / w ≦ 10, the traveling wind accelerated over the turbulent flow generation projection 17 is highly effective in reducing the tire temperature, particularly the temperature near the bead portion. Become.

  In addition, by setting the protrusion inclination angle (θ) of the turbulent flow generation protrusion 17 with respect to the tire circumferential direction to be ± 20 degrees, it is possible to reduce the tire temperature by using the traveling wind, as well as the pneumatic tire. It is possible to further reduce the tire temperature by using the rotating wind generated along with the rotation.

  In particular, construction vehicles (for example, dump trucks, claders, tractors, trailers) and the like are not provided with tire covers (fenders, etc.) that cover the tires. By applying the generation protrusion 17, the flow of the traveling wind over the turbulent flow generation protrusion 17 can be accelerated even when the vehicle speed is low (for example, 10 to 50 km / h), and the tire temperature Can be reduced.

  That is, the traveling wind that flows substantially orthogonal to the turbulent flow generation projection 17 positioned on the front side of the vehicle as the vehicle travels is inside the tire radial direction of the turbulent flow generation projection 17 (that is, near the bead portion 3 ) Can be reduced. On the other hand, the traveling wind that flows substantially orthogonally to the turbulent flow generation projection 17 positioned on the vehicle rear side as the vehicle travels is outside the turbulent flow generation projection 17 in the tire radial direction (that is, the tire side portion). The temperature can be reduced.

[Second Embodiment]
Next, the configuration of the turbulent flow generation projection 17 provided on the pneumatic tire 1 according to the second embodiment will be described with reference to FIGS. 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, and a different part is mainly demonstrated.

  FIG. 8 is a partial cross-sectional perspective view showing a pneumatic tire according to the second embodiment, and FIG. 9 is a partial side view showing the pneumatic tire according to the second embodiment. FIG. 10 is a cross-sectional view in the tread width direction showing the turbulent flow generation projection according to the second embodiment.

  As shown in FIGS. 8 and 9, the turbulent flow generation projection 17 is provided in a range R from the tire width maximum position (P1) to the bead outer position (P2). The turbulent flow generation projection 17 is formed by two projections extending continuously in a substantially arc shape along the tire circumferential direction.

  Specifically, as shown in FIG. 10, the protrusion height from the tire surface 15 to the most protruding position of the turbulent flow generation protrusion 17 is “h”, and the pitch between the turbulent flow generation protrusions 17 is “p”. When the width of the lower side in the tire radial direction of the turbulent flow generation projection 17 is “w”, 1.0 ≦ p / h ≦ 20.0 and 1.0 ≦ (p−w) The relationship of /w≦100.0 is satisfied.

  In particular, the relationship of 2.0 ≦ p / h ≦ 15.0 is preferable, and the relationship of 4.0 ≦ p / h ≦ 10.0 is more preferable. Moreover, it is preferable to set the relationship of 5.0 ≦ (p−w) /w≦70.0, and it is more preferable to set the relationship of 10.0 ≦ (p−w) /w≦30.0. . The pitch (p) is a distance between points obtained by dividing the width in the center in the extending direction of each turbulent flow generation projection 17 into two equal parts.

  When the ratio value (p / h) of the projection height (h) to the pitch (p) is smaller than 1.0, the traveling wind (so-called downward flow) flows in a direction substantially perpendicular to the tire surface 15. May not hit the tire surface 15 between the turbulent flow generation projections 17 and the tire temperature may not be reduced efficiently. On the other hand, if the ratio value (p / h) of the projection height (h) to the pitch (p) is larger than 20.0, the acceleration of the traveling wind over the first turbulent flow generation projection 17 causes the generation of turbulence. In some cases, the tire protrusions 17 are reduced, and the tire temperature cannot be reduced efficiently.

  Also, if the ratio ((p−w) / w) of the projection height (h) to the pitch (p) and the projection height (h) is smaller than 1.0, the turbulent flow generation for the area to be radiated In some cases, the surface area of the protrusion 17 is equal or large, and the temperature (heat storage temperature) in the turbulent flow generation protrusion 17 cannot be reduced. On the other hand, when the ratio value ((p−w) / w) of the projection height (h) to the pitch (p) and the projection height (h) is larger than 100.0, the first turbulent flow generation projection 17 is formed. In some cases, the acceleration of the traveling wind over the road is reduced between the turbulent flow generation projections 17 and the tire temperature cannot be reduced efficiently.

(Modification example according to the second embodiment)
The turbulent flow generation projection 17 according to the first embodiment described above has been described as being formed by two projections extending continuously in a substantially arc shape, but even if deformed as follows, Good. In addition, the same code | symbol is attached | subjected to the same part as the pneumatic tire 1 which concerns on 2nd Embodiment mentioned above, and a different part is mainly demonstrated.

  FIG. 11 is a partial cross-sectional perspective view showing a modified pneumatic tire according to the second embodiment, and FIG. 12 is a partial view showing the modified pneumatic tire according to the second embodiment. It is a side view.

  As shown in FIGS. 11 and 12, the turbulent flow generation projection 17 is formed by a plurality of projections that are divided and extended in a substantially arc shape along the tire circumferential direction. The protrusion inclination angles (θ) of the turbulent flow generation protrusions 17 with respect to the tire circumferential direction are all set equal.

  Specifically, the protrusion inclination angle (θ) with respect to the tire circumferential direction of the turbulent flow generation protrusion 17 is set to ± 20 degrees. That is, in the turbulent flow generation projection 17, the inclination angle with respect to the tire radial direction is set to 70 to 90 degrees.

  Note that the turbulent flow generation projections 17 are not necessarily required to have the same projection inclination angle (θ) with respect to the tire circumferential direction. For example, as shown in FIGS. As long as it is within the above range, different protrusion inclination angles (θ) may be used, and different inclination directions may of course be used.

(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 formed by a plurality of projections extending in a substantially arc shape, thereby reducing the tire temperature. Further, the durability of the tire can be further improved.

  Specifically, the traveling wind S1 generated from the front of the vehicle with the rotation of the pneumatic tire 1 is separated from the tire surface 15 from the turbulent flow generation projection 17 that first gets over, and the front side of the turbulent flow generation projection 17 The vehicle travels over the edge E of the vehicle and accelerates toward the rear of the vehicle (see FIG. 10).

  The accelerated traveling wind S1 flows in a direction substantially perpendicular to the tire surface 15 behind the turbulent flow generation projection 17 (so-called downward flow). At this time, the fluid S2 flowing in the portion (region) where the flow of the traveling wind S1 stays takes heat that stays behind the turbulent flow generation projection 17 and flows again to the traveling wind S1.

  The traveling wind S1 removes the heat of the tire surface 15 between the turbulent flow generation projections 17 and moves over the turbulent flow generation projections 17 to be overcome next, similarly to the case of overcoming the first turbulent flow generation projections 17 described above. It peels from the tire surface 15 from the turbulent flow generation projection 17, gets over the edge portion E on the front side of the turbulent flow generation projection 17, and accelerates toward the rear of the vehicle.

  With this accelerated traveling wind, the tire temperature, particularly the temperature near the bead portion 3 can be reduced, and the durability of the tire can be improved.

[Modification of projection for generating turbulent flow]
The turbulent flow generation projections 17 according to the first embodiment and the second embodiment described above have a substantially quadrangular cross-sectional shape that is substantially orthogonal to the extending direction (that is, the substantially tire circumferential direction). However, it may be modified as follows.

(Modification 1)
First, Modification 1 of the turbulent flow generation projection 17 will be described with reference to FIG. FIG. 15 is a cross-sectional view in the tread width direction showing the turbulent flow generation projection 17 according to the first modification.

  As shown in FIGS. 15A to 15C, the turbulent flow generation projection 17 has a substantially trapezoidal cross-sectional shape substantially orthogonal to the extending direction (that is, the substantially tire circumferential direction). In this cross-sectional shape, the inclination angle (θ1) between one side surface of the turbulent flow generation projection 17 and the tire surface 15 and the inclination angle between the other side surface of the turbulent flow generation projection 17 and the tire surface 15 ( θ2) does not necessarily have to be the same angle.

(Modification 2)
Next, Modification 2 of the turbulent flow generation projection 17 will be described with reference to FIG. FIG. 16 is a cross-sectional view in the tread width direction showing the turbulent flow generation projection 17 according to the second modification.

  As shown in FIGS. 16A and 16B, the turbulent flow generation projection 17 has a substantially triangular cross-sectional shape that is substantially orthogonal to the extending direction (that is, the substantially tire circumferential direction). In this cross-sectional shape, the inclination angle (θ1) between one side surface of the turbulent flow generation projection 17 and the tire surface 15 and the inclination angle between the other side surface of the turbulent flow generation projection 17 and the tire surface 15 ( θ2) does not necessarily have to be the same angle.

(Modification 3)
Next, Modification 3 of the turbulent flow generation projection 17 will be described with reference to FIG. FIG. 17 is a tread width direction sectional view showing a turbulent flow generation projection 17 according to Modification 3.

  As shown in FIGS. 17 (a) and 17 (b), the turbulent flow generation projection 17 has a stepped shape in which the cross-sectional shape substantially perpendicular to the extending direction (ie, substantially the tire circumferential direction) has a step 19. It is formed with. The step 19 may be provided on both side surfaces of the turbulent flow generation projection 17 as shown in FIG. 17A, and as shown in FIG. It may be provided on one side. In this cross-sectional shape, the inclination angle (θ1) between one side surface of the turbulent flow generation projection 17 and the tire surface 15 and the inclination angle between the other side surface of the turbulent flow generation projection 17 and the tire surface 15 ( θ2) need not necessarily be a right angle and need not be the same angle. Also, as shown in FIG. 17, the one surface and the other surface of the step 19 are not limited to the intersection angle (θ3) being only a substantially right angle, and may be inclined.

(Modification 4)
Next, Modification 4 of the turbulent flow generation projection 17 will be described with reference to FIG. FIG. 18 is a cross-sectional view in the tread width direction showing the turbulent flow generation projection 17 according to Modification 4.

  As shown in FIGS. 18A and 18B, the turbulent flow generation projection 17 has a substantially quadrangular cross-sectional shape substantially perpendicular to the extending direction (that is, the substantially tire circumferential direction). The turbulent flow generation projection 17 is formed with a through hole 21 penetrating in a direction substantially orthogonal to the extending direction (that is, substantially the tire radial direction) in order to increase the heat dissipation rate of the turbulent flow generation projection 17 itself. ing.

  In addition, in the turbulent flow generation projection 17 in which the through hole 21 is formed, the cross-sectional shape that is substantially orthogonal to the extending direction is not necessarily a substantially square shape. For example, as shown in FIG. It may be a substantially triangular shape as shown in FIG. 18 (d), or a stepped shape having a step 19 as shown in FIG. 18 (e).

[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, in the first embodiment, the turbulent flow generation projection 17 is formed by one projection that extends continuously in a substantially arc shape along the tire circumferential direction, and the second embodiment. In the above description, it is assumed that the two protrusions extend in a substantially arc shape along the tire circumferential direction. However, the present invention is not limited to this, and as shown in FIG. It may be formed by three or more protrusions extending continuously in a substantially arc shape along the direction.

  In this case, the turbulent flow generation projection 17 is not necessarily formed by a projection extending continuously in a substantially arc shape, but formed by a projection extending in a substantially arc shape along the tire circumferential direction. May be.

  Further, the turbulent flow generation projection 17 does not necessarily have to be formed in parallel when the upper surface substantially parallel to the tire surface 15 and the tire surface 15 (bottom surface) are flat. It may be inclined (ascending / descending) in the rotational direction (vehicle traveling direction), and the opposing surfaces may be asymmetric.

  Further, the turbulent flow generation projection 17 has been described as extending in a substantially arc shape along the tire circumferential direction, but is not limited thereto, and is, for example, substantially linear along the tire circumferential direction. Of course, it may be extended.

  Furthermore, although the pneumatic tire 1 has been described as being a heavy-duty tire, it is not limited thereto, and may of course be a general passenger car radial tire, a bias tire, or the like.

  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 conducted using pneumatic tires according to the following conventional examples and examples will be described. In addition, this invention is not limited at all by these examples.

The configuration of the pneumatic tire and the temperature rise test of the bead portion according to the conventional example and the example will be described with reference to Table 1. The temperature rise test of the bead portion is performed under the conditions of tire size: 53 / 80R63, normal internal pressure, and normal load (construction vehicle tire).

  As shown in Table 1, the pneumatic tire according to the conventional example is not provided with the turbulent flow generation projection 17. The pneumatic tire according to the example is provided with a turbulent flow generation projection 17 (see FIG. 3).

<Bead temperature rise test>
Each pneumatic tire is assembled on a regular rim and mounted on the front wheel of a 360-ton dump truck under the above conditions. After running for 24 hours at a speed of 15 km / h, the bead portion in contact with the rim flange is radially outer. The temperature rise in the bead outer side position (P2) which is the position of was measured. In addition, the temperature in this bead outer side position (P2) is an average value measured uniformly in six places in the tire circumferential direction.

  As a result, the pneumatic tire according to the example has a lower temperature rise (below 5.1 degrees) in the bead portion than the pneumatic tire according to the conventional example, so the temperature in the vicinity of the bead portion should be reduced. I found out that That is, the pneumatic tire according to the example is provided with the turbulent flow generation projection, and thus it has been found that the tire temperature, in particular, the temperature near the bead portion can be reduced.

<Durability test>
Next, FIG. 20 and FIG. 21 show the results of the durability test using the turbulent flow generation projections having different p / h, (p−w) / w, and inclination angle. The vertical axes of the graphs of FIGS. 20 and 21 indicate the heat obtained by measuring the temperature and wind speed of the tire surface when a constant voltage is applied to the heater to generate a certain amount of heat and the heat is sent by a blower. It is a transmission rate. That is, the greater the heat transfer coefficient, the higher the cooling effect and the better the durability. Here, the heat transfer coefficient of a pneumatic tire (conventional example) without a turbulent flow generation projection is set to “100”.

  This heat transfer coefficient measurement test was performed under the following conditions (tires for construction vehicles).

・ Tire size: 53 / 80R63
・ Wheel size: 36.00 / 5.0
・ Internal pressure condition: 600kPa
・ Load condition: 83.6t
・ Speed condition: 20km / h
As shown in FIG. 20, the relationship between the ratio (p / h) of the distance (p) to the height (h) between the turbulent flow generation projections (p / h) and the durability performance is that p / h is 1.0 or more. And the heat transfer rate is increasing by being in the range of 20.0 or less. By setting p / h in the range of 2.0 to 15.0, the heat transfer rate is better and the durability is higher. For this reason, it is preferable to set the range of 1.0 ≦ p / h ≦ 20.0, and it is particularly preferable to set the range of 2.0 ≦ p / h ≦ 15.0, and 4.0 ≦ p. It can be seen that it is more preferable to set the range of /h≦10.0.

  As shown in FIG. 21, the relationship between (p−w) / w and the heat transfer coefficient (measured by the same method as the above heat transfer coefficient) is 1.0 ≦ (p−w) /w≦100.0. The heat transfer coefficient is increased by being within the range. In particular, it is preferably set in the range of 5.0 ≦ (p−w) /w≦70.0, and more preferably set in the range of 10.0 ≦ (p−w) /w≦30.0. I understand that.

It is a partial section perspective view showing the pneumatic tire concerning a 1st embodiment. It is a tread width direction sectional view showing the pneumatic tire concerning a 1st embodiment. 1 is a partial side view showing a pneumatic tire according to a first embodiment. It is a perspective view which shows the protrusion for turbulent flow generation which concerns on 1st Embodiment. It is a partial cross section perspective view which shows the pneumatic tire of the modified example which concerns on 1st Embodiment. It is a partial side view which shows the pneumatic tire of the modified example which concerns on 1st Embodiment. It is a tread width direction sectional view showing the projection for turbulent flow generation concerning a 1st embodiment. It is a partial cross section perspective view which shows the pneumatic tire which concerns on 2nd Embodiment. It is a partial side view which shows the pneumatic tire which concerns on 2nd Embodiment. It is a tread width direction sectional view showing the projection for turbulent flow generation concerning a 2nd embodiment. It is a partial cross section perspective view which shows the pneumatic tire of the modification which concerns on 2nd Embodiment (the 1). It is a partial side view which shows the pneumatic tire of the modified example which concerns on 2nd Embodiment (the 1). It is a partial cross section perspective view which shows the pneumatic tire of the modified example which concerns on 2nd Embodiment (the 2). It is a partial side view which shows the pneumatic tire of the modified example which concerns on 2nd Embodiment (the 2). 10 is a tread width direction cross-sectional view showing a turbulent flow generation projection 17 according to Modification 1. FIG. FIG. 9 is a cross-sectional view in the tread width direction showing a turbulent flow generation projection 17 according to Modification 2. 10 is a tread width direction cross-sectional view showing a turbulent flow generation projection 17 according to Modification 3. FIG. It is a figure which shows the protrusion 17 for turbulent flow generation concerning the modification 4. FIG. It is a partial cross section perspective view which shows the pneumatic tire which concerns on other embodiment. It is a graph which shows the heat transfer rate of the pneumatic tire in an Example (the 1). It is a graph which shows the heat transfer rate 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 ... Inner liner, 9 ... Tread part, 11 ... Belt layer, 15 ... Tire surface, 17 ... Turbulence generation , 17 ... Turbulence generating projection, 19 ... Rim flange, 19 ... Step, 21 ... Through hole, E ... Edge portion

Claims (10)

A pneumatic tire provided with a turbulent flow generation projection for generating turbulent flow on at least a part of a tire surface,
The turbulent flow generation protrusion is provided in a range from a tire width maximum position that is a position of the tire maximum width to a bead outer position that is a position on the outer side in the tire radial direction of the bead portion in contact with the rim flange. Extending in a generally arc shape along the direction,
The projection height (h) from the tire surface to the most projecting position of the turbulent flow generation projection is 7.5 to 20 mm,
In the tread width direction cross section, a protrusion rim distance (a distance from a protrusion innermost position that is the innermost in the tire radial direction of the turbulent flow generation protrusion to a rim outermost position that is the outermost in the tire radial direction of the rim flange) d) is 30-200 mm;
A pneumatic tire characterized by being a heavy duty tire.   When the height of the protrusion from the tire surface to the most protruding position of the protrusion for generating turbulent flow is “h” and the width of the lower side in the tire radial direction of the protrusion for generating turbulent flow is “w”, The pneumatic tire according to claim 1, wherein a relationship of 1.0 ≦ h / w ≦ 10 is satisfied.   The pneumatic tire according to claim 1 or 2, wherein a width (w) of a lower side in the tire radial direction of the turbulent flow generation projection is 2 to 10 mm. The turbulent flow generation collision force is pneumatic tire according to any one of claims 1 to 3, characterized in that the cross-sectional shape substantially perpendicular to the extending direction are formed in substantially rectangular. The turbulent flow generation collision force is pneumatic tire according to any one of claims 1 to 3, characterized in that the cross-sectional shape substantially perpendicular to the extending direction are formed in a substantially trapezoidal. The turbulent flow generation collision force is pneumatic tire according to any one of claims 1 to 3, characterized in that the cross-sectional shape substantially perpendicular to the extending direction are formed in substantially triangular. The turbulent flow generation collision force is according to any one of claims 1 to 3, characterized in that the cross-sectional shape substantially perpendicular to the extending direction are formed in the stepped shape having a step Pneumatic tire. The pneumatic tire according to any one of claims 1 to 6 , wherein the turbulent flow generation protrusion is formed with a through-hole penetrating in a direction substantially orthogonal to the extending direction. . The height of the protrusion from the tire surface to the most protruding position of the turbulent flow generation protrusion is “h”, the pitch between the turbulent flow generation protrusions is “p”, and the turbulent flow generation protrusion is in the tire radial direction. When the width of the lower side is “w”, the relationship of 1.0 ≦ p / h ≦ 20.0 and 1.0 ≦ (p−w) /w≦100.0 is satisfied. The pneumatic tire according to any one of claims 1 to 8 . The protrusion inclination angle with respect to the tire circumferential direction of the turbulent flow generation projection (theta) is the pneumatic tire according to any one of claims 1 to 9, characterized in that it is 20 degrees ±.

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