JPWO2019116626A1 - Heavy load tires - Google Patents

Abstract

The heavy-duty tire has a recess formed in the buttress portion, which opens toward the outside of the tire and has a bottom, and a slope in which the depth from the tire surface is gradually reduced from the bottom to the tire surface to the bottom. The first air in / out promoting unit is provided with a first air in / out promoting unit that promotes the inflow and outflow of air, and the width dimension of the concave portion side of the first air inflow / outflow promoting unit is set smaller than the width dimension of the concave portion. A corner is formed at the connection portion between the tire and the recess.

Description

The present disclosure relates to heavy load tires.

In heavy-duty tires, the temperature near the buttress tends to rise from the viewpoint of load-bearing capacity and size. When the road surface is repeatedly touched and separated by traveling, the buttress portion is repeatedly distorted and the buttress portion generates heat. Therefore, it is conceivable to form a recess in the buttress portion and allow air to flow into the recess to cool the buttress portion. As a tire having a recess formed in the buttress portion, for example, there is a tire described in Japanese Patent Application Laid-Open No. 2009-542528.

It is possible to cool the buttress portion to some extent by forming a recess in the buttress portion, but when the load is increased, the strain increases and the heat generation increases, so that the cooling capacity is required to be improved.

In consideration of the above facts, the present disclosure aims to provide a heavy-duty tire having an improved cooling capacity of a buttress portion.

The heavy-duty tire according to the first aspect is formed in a buttress portion, opens toward the outside of the tire, has a recess having a bottom portion, and the depth from the tire surface is gradually reduced from the bottom portion toward the tire surface. The air inflow / outflow promoting portion having a slope and promoting the inflow / outflow of air to the bottom portion is provided, and the width dimension of the concave portion side of the air inflow / outflow promoting portion is set smaller than the width dimension of the concave portion. A corner portion is formed at the connecting portion between the air inflow / outflow promoting portion and the recess.

The rotation of the heavy-duty tire causes a speed difference between the tire surface and the surrounding air, and air flows into the recess formed in the buttress portion. The air inflow / outflow promoting portion has a slope in which the depth from the tire surface is gradually reduced from the bottom to the tire surface, and promotes the inflow / outflow of air to the bottom. Therefore, the air flowing in the vicinity of the recess can easily flow toward the bottom of the recess along the slope, and the effect of air-cooling the bottom of the recess by the air flowing along the bottom of the recess can be improved. By providing the recess in the buttress portion in this way, the buttress portion can be effectively cooled when the heavy-duty tire is rotated.

Further, since the width dimension of the concave portion side of the air inflow / outflow promoting portion is set smaller than the width dimension of the concave portion and the corner portion is formed at the connecting portion between the air inflow / outflow promoting portion and the concave portion, the corner portion causes the air to flow. When the flow is suddenly changed, turbulence is generated in the recess, and the air is agitated in the recess, so that the cooling efficiency can be further improved.

As described above, the heavy-duty tire of the present disclosure has an excellent effect that the cooling capacity of the buttress portion can be improved.

It is sectional drawing which shows the vicinity of the buttress part of the heavy-duty tire which concerns on one Embodiment of this invention. It is a side view which shows the vicinity of the buttress part of the heavy-duty tire which concerns on one Embodiment of this invention. It is a perspective view which shows the vicinity of the buttress part of the heavy-duty tire which concerns on one Embodiment of this invention. It is a top view which shows the air cooling part provided in the buttress part. FIG. 5 is a cross-sectional view taken along the line 5 (A) -5 (A) of the air-cooled portion shown in FIG. 5 (B) -5 (B) is a cross-sectional view of the air-cooled portion shown in FIG. FIG. 5 is a cross-sectional view taken along the line 5 (C) -5 (C) of the air-cooled portion shown in FIG. It is a top view which shows the modification of the air-cooled part. It is a top view which shows the modification of the air-cooled part. It is a top view which shows the modification of the air-cooled part. It is a top view which shows the modification of the air-cooled part. It is a top view which shows the relationship between the dimension of the air inflow / outflow promotion part and the recess. It is sectional drawing which shows the vicinity of the buttress part of the heavy-duty tire which concerns on another embodiment.

The heavy-duty tire 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. The heavy-duty tire 10 of the present embodiment has the same structure as a general heavy-duty pneumatic tire except for the air-cooled portion 32 described later.

As shown in FIG. 1, the heavy-duty tire 10 includes a carcass 12 straddling a pair of bead cores (not shown).
(Belt configuration)
A belt 14 is arranged on the outer side of the carcass 12 in the tire radial direction. The belt 14 includes a plurality of belt layers. Specifically, the heavy-duty tire 10 according to the first embodiment has a protective belt layer 16 composed of two protective belts 16A and 16B, and a main interlaced belt layer 18 composed of two main interlaced belts 18A and 18B. It also includes a small cross belt layer 20 composed of two small cross belts 20A and 20B. The protective belts 16A and 16B, the main interlacing belts 18A and 18B, and the small interlacing belts 20A and 20B each have a general structure in which a plurality of cords arranged in parallel with each other are coated with a coated rubber. ..

The main interlaced belt layer 18 is arranged outside the small interlaced belt layer 20 in the tire radial direction, and the protective belt layer 16 is arranged outside the main interlaced belt layer 18 in the tire radial direction.

In the heavy-duty tire 10 of the present embodiment, as an example, the angle formed by the cord forming the small crossing belt layer 20 and the tire circumferential direction is 4 to 10 °, and the cord forming the main crossing belt layer 18 and the tire circumference are formed. The angle formed by the directions is 18 to 35 °, and the angle formed by the cord forming the protective belt layer 16 and the tire circumferential direction is 22 to 33 °.

The width of each belt layer in the belt 14 of the present embodiment will be described below.
The width of the small crossing belt 20A adjacent to the outermost side in the tire radial direction of the innermost small crossing belt 20B in the tire radial direction is formed to be slightly narrower than the width of the small crossing belt 20B.
The width of the main crossing belt 18B adjacent to the outer side of the small crossing belt 20A in the tire radial direction is formed wider than that of the small crossing belts 20A and 20B.
The width of the main crossing belt 18A adjacent to the outer side of the main crossing belt 18B in the tire radial direction is wider than that of the small crossing belts 20A and 20B and narrower than that of the main crossing belt 18B.
The width of the protective belt 16B adjacent to the outer side of the main crossing belt 18A in the tire radial direction is formed wider than that of the small crossing belts 20A and 20B and the main crossing belts 18A and 18B.
Further, the width of the protective belt 16A adjacent to the outer side of the protective belt 16B in the tire radial direction and located on the outermost side of the belt 14 is narrower than that of the protective belt 16B and the main interlaced belt 18B, and the small interlaced belt 20A. , 20B, and the main crossing belt 18A are formed wider. The protective belt 16A is arranged on the outermost side in the tire radial direction among the plurality of belt layers. The protective belt 16A is an example of the outermost belt ply in the tire radial direction.
Further, in the belt 14, the fifth protective belt 16B counted from the inside in the radial direction is formed to be the widest, and the end portion 16Be in the tire width direction of the protective belt 16B is arranged on the outermost side in the tire width direction. The protective belt 16B is an example of a belt ply having a maximum width.

A tread rubber 24 constituting the tread 22 is arranged on the outer side of the belt 14 in the tire radial direction. The tread rubber 24 extends outward in the tire width direction of the belt 14 along the carcass 12, and a part of the tread rubber 24 arranged outside in the tire width direction of the belt 14 constitutes a part of the buttress portion 26.

The buttress portion 26 in the present embodiment is grounded from a position of 1/2 × H from the maximum tire width portion Wmax when the tire radial dimension of the maximum tire width portion Wmax and the ground contact end 22E of the tread 22 is H. Refers to the area outside the tire between the end 22E.

Further, the ground contact end 22E of the tread 22 is a tire 10 for heavy load mounted on a standard rim specified in JATMA YEAR BOOK (2017, Japan Automobile Tire Association standard), and is used in the applicable size and ply rating in JATMA YEAR BOOK. This is when the internal pressure of 100% of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table in bold) is filled and the maximum load capacity is loaded. If the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards will be followed.

A plurality of lug grooves 28 are formed in the tread 22 of the heavy-duty tire 10 in the tire circumferential direction. The lug groove 28 formed in the tread 22 extends outward in the tire width direction from the ground contact end 22E of the tread 22, and as shown in FIG. 2, the end portion opens in the buttress portion 26 of the heavy-duty tire 10. ing. In the present embodiment, the land portion between the lug groove 28 and the lug groove 28 adjacent to each other in the tire circumferential direction is referred to as a lug block 30.

As shown in FIGS. 1 to 3, a concave air-cooled portion 32 is formed in the buttress portion 26. In the present embodiment, the air cooling portion 32 is formed on the side surface (buttress portion 26) of each lug block 30 partitioned by the lug groove 28.

(Details of air cooling part)
As shown in FIG. 4, the air-cooled portion 32 includes a recess 34, a first air inlet / outlet promoting portion 36 arranged adjacent to the recess 34, and a second air inlet / outlet promoting portion 38. The first air in / out promotion unit 36 and the second air in / out promotion unit 38 are examples of the air in / out promotion unit.
(Details of recess)
First, the recess 34 will be described first.
As shown in FIG. 4, the recess 34 has a trapezoidal shape in which the bottom 40A on the outer side in the tire radial direction (side in the direction of arrow A) is wider than the upper side 40B on the inner side in the tire radial direction in a plan view from the tire axial direction. It has a presented bottom 40. The bottom side 40A and the top side 40B are parallel to the tangential direction in the tire circumferential direction (arrow B direction), and the side 40C on the front side (arrow B direction side) of the bottom 40 in the tire rotation direction and the tire on the bottom 40. The side 40D on the side opposite to the front side in the rotation direction is inclined with respect to the tire radial direction (arrow A direction). In the present embodiment, the bottom 40 is trapezoidal, but it may be a square, a rectangle, a triangle, or any other polygonal shape, or it may be a circular shape or an elliptical shape.

The bottom 40 has a constant depth along the tire rotation direction as shown in FIG. 5A, but has a depth from the inside in the tire radial direction to the outside in the tire radial direction (side in the arrow A direction) as shown in FIG. 5B. The tire is tilted so that it gradually becomes shallower. The bottom portion 40 may be inclined in a direction along the tire rotation direction. Further, the depth may be constant in the direction along the tire radial direction (arrow A).

As shown in FIG. 1, in the recess 34 of the present embodiment, the bottom portion 40 is arranged outside the tire width direction end portion 16Be of the protective belt 16B formed to be the widest among the belts 14. Further, in the present embodiment, the end portion 16Be of the protective belt 16B in the tire width direction is located inside the central portion of the recess 34 in the tire radial direction in the tire width direction. More specifically, the tire width direction end portion 16Be is arranged between the bottom side 40A and the upper side 40B (see FIG. 4) of the bottom portion 40 on the side closer to the upper side 40B.

As shown in FIG. 4, a recessed side wall 42 forming a part of the recess 34 is formed on the side of the bottom 40 opposite to the front side in the tire rotation direction (arrow B direction side), and the bottom 40 is inside the tire radial direction. A recessed side wall 44 forming another part of the recess 34 is formed (in the direction opposite to the direction of arrow A), and the other part of the recess 34 is formed on the front side of the bottom 40 in the tire rotation direction. The concave side wall 45 that constitutes the structure is formed.

As shown in FIG. 5A, the recessed side wall 42 is inclined with respect to the normal HL standing perpendicular to the surface of the buttress portion 26, and as shown in FIG. 5B, the recessed side wall 44 is also the buttress portion 26. It is inclined with respect to the normal HL standing perpendicular to the surface. Further, although not shown, the recessed side wall 45 is also inclined with respect to the normal HL standing perpendicular to the surface of the buttress portion 26, similarly to the recessed side wall 42 on the opposite side. As a result, the recess 34 is formed so as to extend from the bottom 40 toward the outside of the tire.

(1st air entry / exit promotion section)
Next, the first air inflow / outflow promoting section 36 will be described.
As shown in FIGS. 4 and 5A, the first air inflow / outflow promoting portion 36 is arranged on the front side (arrow B direction side) of the recess 34 in the tire rotation direction. The first air inlet / outlet promoting portion 36 has a rectangular shape in a plan view, and has a concave shape having a slope 46 inclined from the surface of the buttress portion 26 on the front side in the tire rotation direction (arrow B direction side) toward the bottom 40 of the recess 34. It is a part. The slope 46 and the bottom 40 are smoothly connected. In the present embodiment, the first air in / out promoting unit 36 is rectangular in a plan view, but may be another polygon such as a square or a trapezoid.
The term "front side in the tire rotation direction" as used herein refers to the tire rotation direction when the vehicle equipped with the heavy-duty tire 10 moves forward, in other words, the direction downstream of the tire rotation direction.

A side wall 48 perpendicular to the surface of the buttress portion 26 is formed on the tire radial outer side (arrow A direction side) of the slope 46, and is perpendicular to the surface of the buttress portion 26 on the tire radial inner side of the slope 46. The side wall 50 is formed.

As shown in FIG. 4, the width W3 on the tire surface of the first air inlet / outlet promoting portion 36 of the present embodiment is set to be constant in the longitudinal direction and smaller than the width W2 (tire radial direction) of the recess 34 on the tire surface. The width of the slope 46 of the first air inflow / outflow promoting section 36 is also W3. That is, in a plan view, the shape of the first air inflow / outflow promoting portion 36 (the shape of the opening) and the shape of the slope 46 on the tire surface are rectangular.

The end of the first air inflow / outflow promoting portion 36 on the concave portion 34 side (the width of the tire surface portion connected to the concave portion 34) is narrower than the width of the side of the tire surface portion on the front side in the tire rotation direction of the concave portion 34. Longitudinal direction of the front side of the tire surface portion in the tire rotation direction of the recess 34 The side of the recess 34 so as not to be connected to one end and the other end in the middle portion between one end and the other end. (An example of the configuration of claim 4).

The shape of the first air inflow / outflow promoting portion 36 and the slope 46 is not limited to the shape shown in FIG. 4, and the width on the concave portion 34 side may be a trapezoidal shape narrower than the width on the opposite side. The two-dot chain line (virtual line) in FIG. 4 shows the opening of the recess 34 when the first air in / out promoting portion 36 and the second air inflow / outflow promoting portion 38 are not formed.

As shown in FIGS. 5A and 5B, the slope 46 is more gently inclined than the recessed side wall 42 and the recessed side wall 44 of the recess 34. The inclination angle θ1 of the slope 46 with respect to the surface of the buttress portion 26 is preferably in the range of 5 ° to 45 °. Here, if the inclination angle θ1 is larger than 45 °, it becomes difficult to change the direction of the air flowing along the tire surface so as to follow the slope 46. On the other hand, if the average inclination angle of the slope 46 with respect to the tire surface is made smaller than 5 °, the cooling effect is reduced. The inclination angle θ1 is more preferably set within the range of 5 ° to 30 °, and even more preferably set within the range of 15 to 25 °. The cross section of the slope 46 is linear from the side 40C to the surface of the buttress portion 26. By making the slope 46 straight in this way, it is possible to make the inclination angle of the slope 46 constant and make it easier for the direction of the air flow to follow the slope 46.

(2nd air entry / exit promotion department)
Next, the second air inflow / outflow promoting section 38 will be described.
As shown in FIG. 4, the second air inflow / outflow promoting portion 38 is arranged at a position separated from the first air inflow / outflow promoting portion 36 on the tire radial direction outer side (arrow A direction) side of the recess 34. As shown in FIG. 5B, the second air inflow / outflow promoting portion 38 is a concave portion having a slope 52 inclined from the surface of the buttress portion 26 toward the bottom 40 of the recess 34 when viewed in cross section. The slope 52 has a substantially square shape in a plan view, and is smoothly connected to the bottom 40 of the recess 34.

As shown in FIG. 4, a side wall 54 having a steeper slope than the slope 52 is formed on the front side of the slope 52 in the tire rotation direction (arrow B direction side), and on the side opposite to the front side of the slope 52 in the tire rotation direction. A side wall 56 having a steeper slope than the slope 52 is formed. The second air inflow / outflow promoting portion 38 of the present embodiment is formed so that the width dimension on the outer side in the tire radial direction is relatively smaller than the width dimension on the concave portion 34 side (the dimension in the direction intersecting the inclination direction of the slope 52). ing.

The side wall 54 of the second air in / out promoting portion 38 and the recessed side wall 45 of the recess 34 are connected to each other at their ends, and the side wall 56 of the second air inflow / outflow promoting portion 38 and the recessed side wall of the recess 34 are connected to each other. The ends of the 42 are connected to each other.

The slope 52 is more gently inclined than the recessed side wall 42 and the recessed side wall 44 of the recess 34. As shown in FIG. 5B, the inclination angle θ2 of the slope 52 with respect to the surface of the buttress portion 26 is within the range of 5 ° to 45 °, similarly to the inclination angle θ1 of the slope 46 of the first air inflow / outflow promoting portion 36. It is preferable to set it in the range of 5 ° to 30 °, and even more preferably to set it in the range of 15 ° to 25 °. The cross section of the slope 52 is linear from the side 40A to the surface of the buttress portion 26. By making the slope 52 linear in this way, it is possible to make the inclination angle of the slope 52 constant and make it easier for the direction of the air flow to follow the slope 52.

As shown in FIGS. 5A and 5B, the inclination angle θ1 of the slope 46 and the inclination angle θ2 of the slope 52 are smaller than the inclination angle θ3 of the concave side wall 42 of the recess 34 and the inclination angle θ4 of the concave side wall 44. It is preferable that θ3 and θ4 are larger than 40 °. 5C is a cross-sectional view taken along the line 5C-5C of the air-cooled portion 32 shown in FIG.
The cross section of the recessed side wall 42 and the recessed side wall 44 is R-shaped at the boundary portion with the surface of the buttress portion 26. As a result, distortion of the buttress portion 26 due to the load can be suppressed. Further, the shortest distance of the slope 46 from the side 40C to the surface of the buttress portion 26 is longer than the shortest distance from the side 40D of the wall portion 42 to the surface of the buttress portion 26.

As shown in FIG. 4, the end of the first air inflow / outflow promoting portion 36 is connected to one side of the recess 34, and the second air inflow / outflow promoting portion extends to the other side portion extending in a direction different from one side. When the 38s are connected, it is preferable that the first air in / out promoting unit 36 and the second air in / out promoting unit 38 are separated from each other (the configuration of claim 6).

(Action, effect)
The actions and effects of the heavy-duty tire 10 of the present embodiment will be described below.
When the heavy-duty tire 10 rotates due to running, the tread 22 repeatedly touches the ground and separates from the road surface. As a result, the tread 22 is repeatedly distorted, and the buttress portion 26 in particular generates a lot of heat.

In the present embodiment, when the vehicle travels forward and the heavy-duty tire 10 rotates, the air on the front side of the recess 34 in the tire rotation direction flows into the recess 34 with respect to the recess 34.
When the heavy-duty tire 10 rotates due to running, a speed difference occurs between the tire surface and the surrounding air, and the first air in / out promoting portion on the front side in the rotation direction is formed in the recess 34 of the air cooling portion 32 formed in the buttless portion 26. The air on the front side in the tire rotation direction of the air cooling portion 32 flows through the air 36 as shown by the arrow C in FIG. Then, the air flowing into the recess 34 flows along the bottom 40 of the recess 34 and cools the bottom 40 of the recess 34.

Since the slope 46 of the first air inlet / outlet promoting portion 36 is connected to the bottom portion 40 of the recess 34 by being gently inclined from the recess side wall 42 of the recess 34 and the recess side wall 44, the slope 46 of the recess 34 is on the front side in the tire rotation direction. Air can be smoothly guided to the inside of the recess 34 along the slope 46. Then, since the air flowing into the recess 34 flows along the bottom 40 of the recess 34, the bottom 40 can be effectively cooled. That is, the air-cooled portion 32 provided with the first air inflow / outflow promoting portion 36 promotes the inflow of air into the recess 34 as compared with the case without the first air inflow / outflow promoting portion 36, and makes the buttress portion 26 more effective. Can be cooled.

As shown in FIG. 4, the width W3 of the first air inflow / outflow promoting portion 36 that allows air to flow into the recess 34 is set smaller than the width W2 of the recess 34, and is therefore shown in FIGS. 3 and 4. As described above, in the connecting portion between the first air inflow / outflow promoting portion 36 and the recess 34, the concave side wall 45 of the concave portion 34 and the side wall 48 of the first air inflow / outflow promoting portion 36 form a corner portion 58 extending from the bottom portion 40 to the tire surface. At the same time, a corner portion 59 extending from the bottom portion 40 to the tire surface is formed by the recessed side wall 45 of the recess 34 and the side wall 50 of the first air inlet / outlet promoting portion 36. When air flows into the recess 34 from the first air inflow / outflow promoting portion 36 (see arrow C in FIG. 3), the directions of the air flow are suddenly changed by these corners 58 and 59, so that the inside of the recess 34 is changed. Turbulence 60 is generated in the recess 34, and the air is agitated in the recess 34, so that the cooling efficiency can be further improved.
The corners 58 and 59 are portions where the planar side walls extending in the direction of intersecting each other are connected to each other, and are preferably angular because they have a purpose of generating turbulent flow. Chamfering, R chamfering) may be formed. However, if the chamfer is large, the air flow becomes smooth and turbulence is less likely to occur. Therefore, the chamfer size is preferably 20 mm or less, and more preferably 5 mm or less.

Then, the air flowing along the bottom portion 40 is discharged to the outside of the tire along the slope 52 of the second air inflow / outflow promoting portion 38 arranged on the outer side in the tire radial direction of the recess 34, so that the air flows in from the front side in the tire rotation direction. The air can be sequentially discharged to the outside of the tire. As a result, the air-cooled portion 32 promotes the inflow of air into the recess 34 as compared with the case where the second air in / out promoting portion 38 is not provided, and the buttress portion 26 can be cooled more effectively.

If the inclination angle θ1 of the slope 46 of the first air inflow / outflow promoting portion 36 becomes larger than 45 °, it becomes difficult to change the inclination angle θ1 of the air flowing along the tire surface along the direction slope 46. On the other hand, if the inclination angle θ1 of the slope 46 of the first air inflow / outflow promoting portion 36 is smaller than 5 °, the cooling effect is reduced. The inclination angle θ1 of the slope 46 with respect to the tire surface is more preferably set within the range of 5 ° to 30 °, and even more preferably set within the range of 15 ° to 25 °.

When the heavy-duty tire 10 rotates, the temperature of the tread 22 rises near the maximum width of the belt 14, that is, near the end portion 16Be of the widest protective belt 16B forming the belt 14 in the tire width direction. Cheap.

In the present embodiment, the bottom 40 of the recess 34 of the air-cooled portion 32 is arranged outside the tire width direction end portion 16Be of the protective belt 16B in the tire width direction, and the temperature rises most easily in the tire width direction end portion 16Be of the protective belt 16B. It is located in the vicinity. Therefore, the heat generated near the end portion 16Be of the protective belt 16B in the tire width direction can be effectively dissipated to the outside of the tire through the bottom portion 40 of the recess 34, and the maximum width of the protective belt 16B in the tire width direction. The temperature rise in the vicinity of the end portion 16Be can be effectively suppressed.

Further, in the heavy load tire 10 of the present embodiment, the end portion 16Be in the tire width direction of the protective belt 16B is located inside the central portion of the bottom portion 40 of the recess 34 in the tire radial direction in the tire width direction. The tire radial inner portion and the tire radial outer portion of the directional end 16Be can be uniformly cooled.

As the load of the heavy-duty tire 10 increases, the strain in the vicinity of the belt end increases accordingly, and the amount of heat generated in the vicinity of the belt end increases. However, in the heavy-duty tire 10 of the present embodiment, the first air in / out promoting portion 36 and the second air inflow / outflow promoting portion 38 are connected to the recess 34, and further, turbulent flow is generated in the recess 34 to generate the inside of the recess 34. The air is agitated to improve the cooling efficiency, and the buttress portion 26 is efficiently cooled. Therefore, the temperature rise near the end of the belt can be effectively suppressed.

By making the total area of the slope 46 of the first air inflow / outflow promoting portion 36 and the area of the slope 52 of the second air inflow / outflow promoting portion 38 larger than the area of the bottom 40 of the recess 34 when viewed in a plan view. The inflow of air into the recess 34 and the outflow of air can be promoted as compared with the case where the area is equal to or less than the bottom area of the recess 34.

Further, as shown in FIG. 4, the maximum width of the bottom 40 of the recess 34 is a, and the slope at the connection between the slope 46 of the first air inflow / outflow promoting portion 36 on the front side in the tire rotation direction of the recess 34 and the bottom 40 of the recess 34. When the width of 46 is b and the width of the slope 52 at the connection between the slope 52 of the second air inflow / outflow promoting portion 38 and the bottom 40 of the recess 34 is c, a ≧ b and a> c, or a> b. And a ≧ c may be set, and a> b and a> c may be set. It suffices to form a corner portion narrower than the width of the recess of the air inflow / outflow promoting portion for inflowing air into the recess 34, and the width of the air inflow / outflow promoting portion for discharging air in the recess 34 is equal to the side of the recess 34. It may be the same width. If the widths of all the air inflow / outflow promoting parts are narrowed, corners are formed at the connecting portions of the recesses 34 in any of the air inflow / outflow promoting parts, and even if air enters from any of the air inflow / outflow promoting parts, the inside of the recesses 34 Can generate turbulence.

[Other Embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be variously modified and implemented within a range not deviating from the gist thereof. Is.

In the above embodiment, the first air in / out promoting portion 36 is arranged on the front side of the recess 34 in the tire rotation direction, and the second air inflow / outflow promoting portion 38 is arranged on the outer side of the recess 34 in the tire radial direction. 1 Position where the air in / out promotion unit 36 and the second air in / out promotion unit 38 are arranged, the number of the first air in / out promotion unit 36 and the second air in / out promotion unit 38 arranged, the width of the first air in / out promotion unit 36. Is not limited to that described in the above embodiment.

Hereinafter, a modified example in which the positional relationship of the recess 34, the first air in / out promoting portion 36, and the second air inflow / outflow promoting portion 38 is changed will be described. 6 and 7 are schematic views of the air-cooled portion 32, and only the bottom portion and the slope are shown.

The air-cooled portion 32 shown in FIGS. 6A and 6B is an example in which the position of the first air inflow / outflow promoting portion 36 with respect to the recess 34 is changed to remove the corner portion 59 (see FIG. 4) and leave only the corner portion 58. The first air inflow / outflow promoting portion 36 is in contact with an intermediate portion between one end and the other end in the longitudinal direction on the side of the tire surface portion of the recess 34, is in contact with one end, and is in contact with the other end. It is connected to the side of the recess 34 so as not to be connected to (an example of the configuration of claim 5).

The air-cooled portion 32 shown in FIG. 6B is a modified example of the air-cooled portion 32 shown in FIG. 6A, and is an example in which the first air inlet / outlet promoting portion 36 is provided on the rear side of the recess 34 in the tire rotation direction.

The air-cooled portion 32 shown in FIG. 7A is an example in which the first air in / out promoting portion 36 is provided on the four sides of the recess 34.

The air-cooled portion 32 shown in FIG. 7B is an example in which two first air inflow / outflow promoting portions 36 are provided on one side of the recess 34. As a result, the number of turbulent flows 60 generated in the recess 34 can be increased, and the cooling efficiency can be improved.

In the above embodiment, the first air in / out promoting portion 36 is provided on the front side of the recess 34 in the tire rotation direction when the vehicle travels forward, and when the heavy load tire 10 rotates, the tire rotation of the recess 34 with respect to the recess 34. The case where the air on the front side in the direction flows into the recess 34 has been described. For example, as shown in FIGS. 6B and 7A, the first air inflow / outflow promoting portion 36 is provided on both the front side in the tire rotation direction and the rear side in the tire rotation direction. By providing this, turbulent flow can be generated in the recess 34 even when the vehicle travels backward. Further, by providing the first air in / out promoting portion 36 on both the front side in the tire rotation direction and the rear side in the tire rotation direction of the recess 34, there is no restriction on the mounting direction (designation of the rotation direction) of the heavy load tire 10.

In the above embodiment, the case where air flows in from the front side of the recess 34 in the tire rotation direction when the vehicle travels forward has been described, but when the conditions such as the arrangement position and shape of the recess 34 change, for example, It is conceivable that air may flow into the recess 34 from a direction different from the front side in the tire rotation direction, such as the outside in the tire radial direction. In such a case, a narrow first air inflow / outflow promoting portion 36 is provided on the side where air flows in so as to generate turbulent flow in the recess 34.

In the above embodiment, the bottom 40 of the recess 34 is not located outside the tire width direction end 16Ae of the protective belt 16A arranged on the outermost side in the tire radial direction in the belt 14, but FIG. As shown in the above, the bottom portion 40 may be extended outward in the tire radial direction so that the bottom portion 40 of the recess 34 is located outside the tire width direction end 16Ae of the outermost protective belt 16A in the tire width direction.

When the heavy-duty tire 10 travels on a rough road or the like, cracks may occur on the surface of the tread 22. When the tire width direction end 16Ae of the outermost protective belt 16A in the tire radial direction generates heat and the temperature rises, the durability of the surrounding tread rubber 24 near the tire width direction end 16Ae decreases, and it occurs on the surface of the tread 22. The cracks may develop toward the rubber part with reduced durability.

As shown in FIG. 8, by arranging the bottom portion 40 of the recess 34 on the outer side in the tire width direction of the tire width direction end 16Ae of the outermost protective belt 16A in the tire radial direction, the bottom portion 40 is brought closer to the tire width direction end 16Ae. be able to. As a result, it is possible to suppress the temperature rise in the vicinity of the tire width direction end 16Ae, maintain the durability of the tread rubber 24 in the vicinity of the tire width direction end 16Ae, and crack the surface of the tread 22 in the tire width direction end. It is possible to suppress the advance toward the tread rubber 24 in the vicinity of 16Ae.

In the above embodiment, the end of the first air inlet / outlet promoting portion 36 opposite to the concave portion 34 side is terminated at the surface of the buttress portion 26, but as shown in FIG. 9, the first air inlet / outlet promoting portion The end of the 36 opposite to the recess 34 side may be connected (opened) to the lug groove 28. As a result, in addition to the air on the side surface of the tire, the air in the lug groove 28 can flow into the recess 34. Further, in the above embodiment, the end of the second air inlet / outlet promoting portion 38 opposite to the concave portion 34 side is terminated at the surface of the buttress portion 26, but as shown in FIG. 9, the second air inlet / outlet The end portion of the promoting portion 38 opposite to the concave portion 34 side may be connected (opened) to the lug groove 28 or the tread end.

The disclosure of Japanese Patent Application No. 2017-237701 filed on 12 December 2017 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

10 ... Heavy load tire, 16B ... Protective belt (maximum width belt ply), 16A ... Protective belt (outermost belt ply in tire radial direction), 16Ae ... Tire width direction end, 16Be ... Tire width direction end, 26 ... Buttless part (tire surface), 34 ... concave, 36 ... first air in / out promotion part (air in / out promotion part), 38 ... second air in / out promotion part (air in / out promotion part), 40 ... bottom, 46 ... slope, 52 ... slope, 58 ... corner, 59 ... corner

Claims (11)

A recess formed in the buttress, which opens toward the outside of the tire and has a bottom,
An air inflow / outflow promoting portion having a slope in which the depth from the tire surface is gradually reduced from the bottom to the tire surface and promoting air inflow / outflow to the bottom.
With
The air inlet / outlet promoting portion is a heavy-duty tire in which the width dimension on the concave portion side is set smaller than the width dimension of the concave portion, and a corner portion is formed at a connecting portion between the air inlet / outlet promoting portion and the concave portion. The air in / out promoting portion is formed in a direction different from the front side of the recess in the tire rotation direction and the front side of the recess in the tire rotation direction.
When the buttress portion is viewed in a plan view, the maximum width of the bottom portion of the recess is a, the width of the slope at the connection portion between the air inlet / outlet promoting portion and the recess on the front side in the tire rotation direction of the recess is b, and the recess. When the width of the slope at the connection portion between the air inflow / outflow promoting portion and the recess formed in a direction different from the front side in the tire rotation direction is c.
The heavy-duty tire according to claim 1, wherein a ≧ b and a> c, or a> b and a ≧ c. The heavy-duty tire according to claim 2, wherein a> b and a> c are set. When the buttress portion is viewed in a plan view, the end portion of the air inflow / outflow promoting portion formed on the front side in the tire rotation direction on the recess side is one end of the side constituting the recess and the other end of the side. The heavy-duty tire according to any one of claims 1 to 3, which is connected to an intermediate portion between the tire and the tire so as not to be connected to the one end portion and the other end portion. When the buttress portion is viewed in a plan view, the end portion of the air inflow / outflow promoting portion formed on the front side in the tire rotation direction on the concave portion side is one of the end portions or the other end portion of the side constituting the concave portion. The heavy-duty tire according to any one of claims 1 to 3, which is connected to any one of them. In the recess, the air inlet / outlet promoting portion is connected to one side portion and the other side portion which is connected to the end portion of the one side portion and extends in a direction different from the one side portion. Has been formed and
Claims 1 to 1 that the air in / out promoting portion formed by connecting to one side portion and the other air inflow / outflow promoting portion formed by connecting to the other side portion are separated from each other. The heavy-duty tire according to any one of claims 5. The load according to any one of claims 1 to 6, wherein the end portion of the belt ply having the maximum width constituting the belt in the tire width direction is located inside the bottom of the recess in the tire width direction. Heavy tires. The heavy load tire according to claim 7, wherein the end portion of the maximum width belt ply in the tire width direction is located inside the central portion in the tire radial direction of the bottom portion in the tire width direction. The method according to any one of claims 1 to 8, wherein the end portion of the outermost belt ply in the tire radial direction constituting the belt is located inside the bottom of the recess in the tire width direction. Heavy load tires. Any one of claims 1 to 9, wherein the total area of the slopes when the air inflow / outflow promoting portion is viewed in a plan view is set to be larger than the area of the bottom portion when the recess is viewed in a plan view. Heavy load tires described in the section. The heavy-duty tire according to any one of claims 1 to 10, wherein a plurality of the air inflow / outflow promoting portions are formed on one side forming the recess when the buttress portion is viewed in a plan view.