WO2015019975A1 - Tire - Google Patents

Abstract

A tire is provided with: a tread which comes into contact with the road surface; side walls which continue into the tread; circumferential direction concave parts which are formed on the outer surface of the side walls along the tire circumferential direction and which concave inward along the tread width direction; and blocks which are formed in the inside of the circumferential direction concave parts and which protrude outward along the tread width direction. In cross-section including the rotational axis of the tire, the side walls have a rim-side outer surface which is formed from the outer circumferential edge of a bead heel, in which the side walls separate from a rim flange to which the tire attaches, to the inner circumferential edge of the circumferential direction concave parts. In the aforementioned cross-section, the blocks do not reach an imaginary line which extends from the aforementioned inner circumferential edge to the outer circumferential side of the rim-side outer surface. With said tire, it is possible to inhibit the temperature from rising at the side walls (especially on the section towards the bead) while improving the durability of the blocks.

Description

tire

The present invention relates to a tire having a tread in contact with a road surface and a sidewall connected to the tread.

In the case of pneumatic tires for vehicles, heat generation during tire rolling is a problem. The temperature rise of the tire due to heat generation may cause a change over time such as a change in physical properties of the tire material, or a tread breakage during high speed running. In particular, in off-road radial (ORR) tires and truck bus radial (TBR) tires that are used under heavy loads, the sidewall (particularly the portion near the bead) is deformed due to friction with the rim flange or push-up from the rim flange. However, heat is easily generated at the deformed portion. The heat generated in the sidewall accelerates the deterioration of the rubber and deteriorates not only the durability of the bead but also the durability of the tire. For this reason, suppression of the temperature rise of the part near the bead of the sidewall is desired.

The following Patent Document 1 discloses a tire having turbulence generation projections formed on a sidewall as a bead temperature rise suppression means on a sidewall. A turbulent flow having a high flow velocity is generated along the sidewall surface by the turbulent flow generation projection, and heat dissipation from the sidewall is promoted. As a result, the temperature rise in the portion near the bead is suppressed.

International Publication WO2009 / 084634

However, the turbulent flow generation protrusion protruding from the sidewall surface may be damaged by contact with an obstacle or the like. In particular, in ORR tires that are often used on rough roads, turbulent flow generation protrusions are likely to be damaged, and it may be difficult to suppress temperature rise.

An object of the present invention is to provide a tire capable of improving the durability of a turbulent flow generation projection (block) and suppressing the temperature rise of a sidewall (particularly, a portion near a bead).

A feature of the present invention is a tire having a tread in contact with a road surface and a sidewall continuous with the tread, formed on the outer surface of the sidewall along the tire circumferential direction, and along the tread width direction. A circumferential recess recessed inward, and a block formed inside the circumferential recess and projecting outward along the tread width direction, wherein the sidewalls of the tire In the cross section including the rotation axis, the outer surface of the rim side formed from the outer peripheral edge of the bead heel from which the sidewall is separated from the rim flange to which the tire is attached to the inner peripheral edge of the circumferential recess, Provided is a tire in which the block does not reach a virtual line obtained by extending the outer surface on the rim side from the inner peripheral edge to the outer peripheral side.

According to the above feature, by forming the circumferential recess, the distance between the high temperature portion inside the sidewall (particularly the portion near the bead) and the heat radiation surface (surface of the circumferential recess) can be reduced. The heat inside the tire can be easily dissipated, and the temperature rise of the rubber constituting the tire can be effectively suppressed. Moreover, the volume of the rubber which comprises a side wall can be reduced by the circumferential recessed part, and a weight reduction and manufacturing cost can also be suppressed. In addition, the said characteristic is a characteristic in the tire single-piece | unit (in the state which is not assembled | attached to the wheel).

Here, the rim side outer surface is on a first arc curve centered on a point located inside the tread width direction in the cross section, and the imaginary line is the first arc curve in the cross section. Is a line extending from the inner peripheral edge to the outer peripheral side.

Further, in the cross section, if the shortest distance between the block and the imaginary line is X and the maximum depth of the circumferential recess with respect to the imaginary line is Dm, 0 <X ≦ 0.7 Dm is preferable. .

Further, the circumferential recess has an inner wall surface formed from the inner peripheral edge to the bottom surface of the circumferential recess, and the height of the block is a position of the outer peripheral edge portion of the inner wall surface in the cross section. It is preferable that

In the cross section, it is preferable that the maximum depth of the inner wall surface with respect to the imaginary line is 15 mm to 35 mm.

In the cross section, it is preferable that the inner wall surface forms a curve that is recessed inward in the tread width direction from the inner peripheral edge.

Further, in the cross section, it is preferable that the inner wall surface is on a second circular arc curve centering on a point located outside in the tread width direction.

The height of the block is preferably 3 mm to 25 mm.

Further, it is preferable that the blocks are arranged at a predetermined pitch in the tire circumferential direction, and the width of the block in the tire circumferential direction is 2 mm to 10 mm.

Further, when the height of the block is h, the predetermined pitch is P, and the width of the block is w, 1 ≦ (P / h) ≦ 50 and 1 ≦ [(P−w) / It is preferable that w] ≦ 100 is satisfied.

Further, it is preferable that at least a part of the block is disposed on the inner wall surface.

FIG. 1 is a side view of a tire 1 according to the first embodiment. FIG. 2 is a perspective sectional view of the tire 1. FIG. 3 is a cross-sectional view of the tire 1. FIG. 4A is an enlarged cross-sectional view of the tire 1, and FIG. 4B is an enlarged cross-sectional view showing a circumferential recess of the tire 1. FIG. 5 is an enlarged cross-sectional view showing the circumferential recess in the no-load state and the normal load state. FIG. 6A is an enlarged perspective view of the circumferential recess, and FIG. 6B is an enlarged plan view of the circumferential recess. FIG. 7A is an enlarged cross-sectional view illustrating a turbulent flow generation state, and FIG. 7B is an enlarged plan view illustrating a turbulent flow generation state. FIG. 8A is an enlarged perspective view of a circumferential recess of the tire according to the second embodiment, and FIG. 8B is an enlarged plan view of the circumferential recess. FIG. 9A is an enlarged perspective view of a circumferential recess of a tire according to a modification of the second embodiment, and FIG. 9B is an enlarged plan view of the circumferential recess. FIG. 10A is an enlarged perspective view of a circumferential recess of the tire according to the third embodiment, and FIG. 10B is an enlarged plan view of the circumferential recess. FIG. 11A is an enlarged sectional view of a conventional tire, and FIG. 11B is an enlarged sectional view of a comparative tire. Fig.12 (a) is an expansion perspective view of the circumferential recessed part of the tire which concerns on 4th Embodiment, FIG.12 (b) is an enlarged plan view of the said circumferential recessed part. FIG. 13A is an enlarged perspective view of a circumferential recess of the tire according to the fifth embodiment, and FIG. 13B is an enlarged plan view of the circumferential recess. FIG. 14 is an enlarged plan view of a circumferential recess of the tire according to the sixth embodiment. FIG. 15 is an enlarged plan view of a circumferential recess of the tire according to the seventh embodiment. FIGS. 16A to 16E are plan views of a circumferential recess of a tire according to another embodiment.

Hereinafter, embodiments will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component. It should be understood that the drawings schematically show the components, and that the components in the drawings are not actually shown in the drawings. Also, the actual dimensions of the components and the actual ratios between the components may be shown differently in the drawings.

[First Embodiment]
(1) Configuration of Tire The tire 1 according to the first embodiment is a heavy duty pneumatic tire that is mounted on a construction vehicle such as a dump truck. As shown in FIGS. 1 to 3, the tire 1 includes a tread 10 that is in contact with a road surface during traveling, and sidewalls 20 that are continuous with the tread 10. Further, the tire 1 includes a carcass 40 forming a skeleton thereof, beads 30 assembled to a rim flange 61 (see FIG. 3) of the rim wheel 60, and a tire radial direction Td of the carcass 40 in the tread 10. Belt [belts] 50 disposed on the outside of the belt.

The carcass 40 includes a carcass cord and a layer made of rubber that covers the carcass cord. One side of the carcass 40 is wound around the bead core of the bead 30 from the tread 10 through the sidewall 20, and forms a turn-ups that is folded back from the inside to the outside in the tread width direction Tw. Yes. The folded portion extends outward in the tire radial direction Td, and its edge is located at a position of 40% to 65% of the tire height H (see FIG. 3). The tire height H will be described in detail later.

The belt 50 is composed of a steel cord and a rubber component impregnated in the steel cord. The belt 50 includes a plurality of layers [plies], and the plurality of layers are stacked in the tire radial direction Td. The beads 30 are disposed along the tire circumferential direction Tc, and are disposed on both sides of the tread width direction Tw via the tire center plane CL. The pneumatic tire 1 has a plane-symmetric structure with respect to the tire center plane CL, and only one of the pair of beads 30 is shown in FIGS.

In a cross-sectional plane including the rotation axis of the tire 1, an outer peripheral edge [bead ヒ ー ル heal [outer circumferential edge] 61 a on the outer surface of the sidewall 20 to an inner peripheral edge [circumferential depressed portion] 100 A rim-side outer surface [rim-side outer surface] 80 is formed in a range up to the inner inner circumferential edge 100a. The bead heel outer peripheral edge 61 a is a position where the sidewall 20 is separated from the rim flange 61 of the rim wheel 60, and an outermost peripheral position where the tire 1 contacts the rim flange 61 in a state where the tire 1 is assembled to the rim wheel 60. It is.

Here, the state in which the tire 1 is assembled to the rim wheel 60 means a state in which the tire 1 is assembled to a standard rim defined in the standard with air pressure corresponding to the maximum load defined in the standard. The above-mentioned standard indicates a standard by JATMA YEAR BOOK (2010 edition, Japan Automobile Tire Association). In addition, when the TRA standard, the ETRTO standard, etc. are applied in the place of use or the manufacturing place, the above standard shall conform to each standard.

As shown in FIG. 4A, the rim-side outer surface 80 draws a first arcuate curve [Rc1] having a radius of curvature R1 in the cross section described above. The center C1 of the first arc curve Rc1 is located inside the tread width direction Tw from the first arc curve Rc1. That is, the rim side outer surface 80 forms a curved surface that bulges outward. By forming the rim-side outer surface 80 in this way, rigidity can be imparted to a region near the bead 30 of the sidewall 20. The center C1 is preferably on a straight line extending in the tread width direction Tw from the tire maximum width position m.

(2) Configuration of circumferential recess portion The circumferential recess portion 100 is formed on the outer surface of the sidewall 20, is recessed inward, and extends in the tire circumferential direction Tc. The length of the circumferential recess 100 in the tire radial direction Td and the depth in the tread width direction Tw are preferably determined as appropriate according to the size of the tire 1 and the type of vehicle to be mounted.

The circumferential recess 100 includes an inner wall surface [inner wall surface] 101 located on the inner circumference side, an outer wall surface [outer wall surface] 102 located on the outer circumference side, and a bottom surface located between the inner wall surface 101 and the outer wall surface 102. [bottom surface] 103. In other words, the circumferential recess 100 is divided into three regions along the tire radial direction Td: a region where the inner wall surface 101 is formed, a region where the outer wall surface 102 is formed, and a region where the bottom surface 103 is formed. The

4A and 4B, the inner wall surface 101 is formed in a range from the inner peripheral edge 100a to the bottom surface 103. That is, the inner wall surface 101 and the bottom surface 103 are continuous. Further, the inner wall surface 101 draws a second circular arc curve Rc2 having a curvature radius R2 in the above-described cross section. The center C2 of the second arc curve Rc2 is located outside the second arc curve Rc2 in the tread width direction Tw. That is, the inner wall surface 101 forms a curved surface that is recessed inward.

The curvature radius R2 is preferably 50 mm or more in a state where the internal pressure of the tire 1 is a normal internal pressure and no load is applied to the tire 1 (no load state). The normal internal pressure is an internal pressure defined in the above-described standard. Moreover, the normal load mentioned later is also the maximum load prescribed | regulated by the standard mentioned above.

The maximum depth D of the inner wall surface 101 from the imaginary line Vc1 obtained by extending the first circular arc curve Rc1 on the circumferential recess 100 is set to be within a range of 15 mm to 35 mm. The first arc curve Rc1 and the virtual line Vc1 are on a single arc curve, and in FIG. 4A and FIG. 4B, the virtual line Vc1 is indicated by a dotted line. Note that the maximum depth D is an interval from the outer peripheral edge 100c of the inner wall surface 101 to the virtual line Vc1, as shown in FIG. 4B. That is, in the cross section described above, the maximum depth D is the distance between the intersection of the normal line passing through the outer peripheral edge 100c and the virtual line Vc1 and the outer peripheral edge 100c.

The inner wall surface 101 is provided within a predetermined range from the bead heel outer peripheral edge 61a to the outer side in the tire radial direction Td. Specifically, when the tire height in the above-described no-load state is H, the inner wall surface 101 is in a state where the internal pressure of the tire 1 is a normal internal pressure and a normal load is applied to the tire 1 (normal In the load state), the bead heel is provided within a range of 25% or less of the tire height H from the outer periphery 61a of the bead heel.

The tire height H is the length from the inner peripheral edge of the tire 1 to the surface of the tread 10 when the tire 1 is assembled to the rim wheel 60, as shown in FIG. In the tire 1, the curvature radius Ra of the inner wall surface 101 in the above-described no-load state and the curvature radius Rb of the inner wall surface 101 in the above-described normal load state are (Ra−Rb) /Ra≦0.5. Meet the relationship.

As shown in FIG. 5, the curvature radius R2 of the inner wall surface 101 changes from the curvature radius Ra in the no-load state to the curvature radius Rb in the normal load state. In the present embodiment, the tire 1 is configured such that the rate of change of the curvature radius R2 when the curvature radius R2 changes from the curvature radius Ra to the curvature radius Rb is 0.5 or less.

As shown in FIG. 4A, the outer wall surface 102 is formed on the outer peripheral side of the circumferential recess 100. The outer wall surface 102 is formed in the range from the outer peripheral edge 100 b of the circumferential recess 100 to the bottom surface 103. In addition, it is preferable that the outer wall surface 102 also forms a curved surface that is recessed inward, like the inner wall surface 101. Further, the bottom surface 103 is located on the inner side in the tread width direction Tw than the outer surface of the sidewall 20, and is continuous with the inner wall surface 101 and the outer wall surface 102.

As described above, the circumferential recess 100 having the inner wall surface 101, the outer wall surface 102, and the bottom surface 103 is formed on the sidewall 20 so as to be recessed inward along the tread width direction Tw. Since the circumferential recess 100 is formed to be recessed, the volume of rubber forming the sidewall 20 is reduced.

(3) Structure of block The block (fin) formed in the circumferential recess 100 will be described with reference to the drawings. A block (turbulent flow generation protrusion) 110 that protrudes outward in the tread width direction Tw is formed inside the circumferential recess 100. In addition, the inside of the circumferential recess 100 means a region between the inner peripheral edge 100a and the outer peripheral edge 100b of the circumferential recess 100 along the tire radial direction Td.

In the present embodiment, a first block 111 and a second block 112 are formed as the block 110. The first block 111 and the second block 112 are each formed at predetermined intervals in the tire circumferential direction Tc. In the present embodiment, two types of blocks (first block 111 and second block 112) are formed as the block 110, but only one type of block (for example, the first block 111) is formed as the block 110. May be.

In this embodiment, at least a part of the block 110 is disposed on the inner wall surface 101. Specifically, all the first blocks 111 and some of all the second blocks 112 are arranged on the inner wall surface 101. Note that at least a part of the block 110 may be disposed on the inner wall surface 101, and for example, only a part of all the first blocks 111 may be disposed on the inner wall surface 101.

As shown in FIGS. 6A and 6B, the first block 111 is formed on the inner peripheral side of the circumferential recess 100 in the tire radial direction Td, and the second block 112 is the circumferential recess 100. It is formed on the outer peripheral side in the tire radial direction Td. That is, the second block 112 is formed outward from the first block 111 along the tire radial direction Td.

In the present embodiment, the first block 111 and the second block 112 are formed on a straight line along the tire radial direction Td. The first block 111 and the second block 112 are arranged radially with respect to the center C of the tire 1 (see FIG. 1).

The first block 111 and the second block 112 are spaced apart along the tire radial direction Td. Further, the width w of the first block 111 in the tire circumferential direction Tc and the width w of the second block 112 in the tire circumferential direction Tc are the same. Specifically, the width w of the first block 111 and the second block 112 is 2 mm or more and 10 mm or less. When the side surface of the first block 111 (or the second block 112) is inclined and the width is not constant, the width w is an average value of the maximum width and the minimum width.

The distance L1 between the first block 111 and the second block 112 in the tire radial direction Td is 15% to 30% of the pitch P in the tire circumferential direction Tc of the first block 111 (or the second block 112). preferable. When the distance L1 is less than 15% of the pitch P, the air flow that has entered the circumferential recess 100 is hindered, and the region in which the air stays in the circumferential recess 100 becomes wide. On the other hand, when the distance L1 exceeds 30% of the pitch P, it is difficult to generate an air flow that repeatedly adheres to and peels from the bottom surface 103.

As shown in FIG. 6B, the pitch P is between the center of the first block 111 (or the second block 112) and the center of the adjacent first block 111 (or the second block 112). The linear distance along the tire circumferential direction Tc.

In this embodiment, the height h of the block 110 (the first block 111 and the second block 112) along the tread width direction Tw is 3 mm or more and 25 mm or less. The height h of the first block 111 (or the second block 112) is perpendicular to the inner wall surface 101, the outer wall surface 102, or the bottom surface 103 where the first block 111 (or the second block 112) is formed. Is measured.

In this embodiment, the height h, pitch P, and width w of the block 110 (the first block 111 or the second block 112) are 1 ≦ (P / h) ≦ 50 and 1 ≦ [(P− w) / w] ≦ 100 is satisfied.

The outer surface 111S of the first block 111 and the outer surface 112S of the second block 112 are preferably flat surfaces. The angle formed between the outer surface 111S and the outer peripheral side surface 111a of the first block 111 is preferably an obtuse angle. If it does in this way, the mold release property at the time of removing the tire 1 from a metal mold | die at the time of manufacture of the tire 1 will become favorable. Therefore, chipping of the tire 1 at the time of manufacture can be suppressed, and a high-quality tire 1 can be manufactured.

Similarly, the angle formed between the outer surface 112S and the inner peripheral side surface 112a of the second block 112 is preferably an obtuse angle. The angle formed between the outer surface 112S and the outer peripheral side surface 112b of the second block 112 is also preferably an obtuse angle. Further, similarly, with respect to the side surfaces of the first block 111 and the second block 112 in the tire circumferential direction Tc, the angle formed with the outer surface 111S and the outer surface 112S is preferably an obtuse angle.

As shown in FIG. 4B, the outer end (outer surface 111S or 112S) of the block 110 (the first block 111 and the second block 112) in the tread width direction Tw is inward of the virtual line Vc1. Is located. That is, the height h of the block 110 (the first block 111 and the second block 112) is smaller than the maximum depth Dm of the circumferential recess 100. When a plurality of types of blocks 110 (the first block 111 and the second block 112) are formed as in the present embodiment, the height h of at least one type of block 110 is made smaller than the maximum depth Dm. Just do it.

Furthermore, in the cross section described above, the shortest distance X between the end of the block 110 (the first block 111 or the second block 112) in the tread width direction Tw and the virtual line Vc1 is 0 <X ≦ 0.7 Dm. Specifically, the shortest distance X is the minimum length of a perpendicular line extending from the virtual line Vc1 to the outer end (the outer surface 111S or 112S) in the tread width direction Tw of the block 110. The height h of the block 110 is preferably changed according to the arrangement position along the tire radial direction Td, and the height h is preferably increased as the depth of the circumferential recess is increased (however, Since 0 <X ≦ 0.7 Dm, the outer surfaces 111S and 112S do not reach the virtual line Vc1). For example, when the maximum depth Dm of the circumferential recess coincides with the maximum depth D of the inner wall surface 101, the height h of the block 110 is maximized at the position of the outer peripheral edge 100 c of the inner wall surface 101.

(4) Turbulence Generation Next, turbulence generation by the circumferential recess 100 will be described with reference to the drawings. As shown in FIG. 7A, as the tire 1 rotates, the air flow S1 along the inner wall surface 101 and the bottom surface 103 in the circumferential recess 100 is blocked by the block 110 (the first block 111 or the second block 112). , The same shall apply hereinafter) is peeled off from the inner wall surface 101 and the bottom surface 103 and gets over the block 110. At this time, on the back side of the block 110 (the right side in FIGS. 7A and 7B), an air flow retention region is generated. The air flow S <b> 1 over the block 110 is reattached to the inner wall surface 101 and the bottom surface 103 between the next block 110. Thereafter, the air flow S <b> 1 is separated again by the next block 110 and gets over the next block 110. At this time, a stagnant region of airflow is also generated on the front side of the next block 110 (the left side in FIGS. 7A and 7B).

Here, the air flow S2 in the stay region formed on the back side of the block 110 is drawn into the air flow S1 by taking heat from the back side of the block 110. In addition, the air flow S3 in the stay region formed on the front side of the block 110 takes heat from the front side of the next block 110 and is drawn into the air flow S1. Further, as shown in FIG. 7 (b), the first block 111 and the second block 112 are separated along the tire radial direction Td, and therefore, between the first block 111 and the second block. An air flow S4 is generated. Since the air flow S4 flows without being obstructed by the first block 111 and the second block 112, it is faster than the air flow S1 described above. Accordingly, the air flows S2 and S3 described above are also drawn into the air flow S4 after depriving the block 110 of heat. Turbulent flow is generated in the circumferential recess 100 of the tire 1 by the air flow S1 over the block 110 and the air flow S4 that flows fast without being blocked by the block 110.

Here, as shown in FIG. 7B, the air flow S0 along the rim side outer surface 80 smoothly flows into the circumferential recess 100 through the inner wall surface 101, and merges with the air flow S1 or S4. To do. In the present embodiment, since the inner wall surface 101 is a curved surface, the air flow S0 can easily flow into the circumferential recess 100 along the inner wall surface 101.

In the cross section described above, the outer end (outer surface 111S or 112S) of the block 110 in the tread width direction Tw is positioned inward of the virtual line Vc1. Accordingly, as shown in FIG. 7 (b), a part of the air flow S1 diverges after getting over the block 110 and collides with the inner wall surface 101 (outer wall surface 102) to join the air flow S1 or S4. Air flow S5.

(5) Effect As described above, the circumferential recess 100 is formed on the outer surface of the sidewall 20 in the tire 1 of the present embodiment. By forming the circumferential recess 100, the distance between the high temperature portion inside the tire 1 (particularly, the portion near the bead 30) and the heat radiation surface (the surface of the circumferential recess 100) can be reduced. For this reason, the heat inside the tire 1 can be easily radiated, and the temperature rise of the rubber constituting the tire 1 can be effectively suppressed.

Also, the volume of rubber constituting the sidewall 20 can be reduced by the circumferential recess 100 as compared with the case where the circumferential recess 100 is not formed. That is, since the volume of the deformed rubber is reduced, heat generation due to the deformation of the rubber can be suppressed. Furthermore, weight reduction and manufacturing cost can also be suppressed by reducing the volume of rubber.

Further, the rim side outer surface 80 forms a curved surface that swells outward along the above-mentioned first circular arc curve Rc1. Therefore, rigidity can be imparted to the portion of the sidewall 20 near the bead 30. On the other hand, the inner wall surface 101 of the circumferential recess 100 forms a curve that is recessed inward along the above-described second arc curve Rc2 in the cross section. Accordingly, the rotation of the tire 1 causes the air flow S0 along the rim side outer surface 80 to smoothly flow into the circumferential recess 100 through the inner wall surface 101, and the amount of air flowing into the circumferential recess 100 increases. As a result, heat dissipation is promoted and the temperature rise of the rubber constituting the tire 1 can be effectively suppressed.

Further, on the circumferential recess 100, a block 110 (first block 111 and second block 112) is formed. If the block 110 is formed directly on the sidewall 20 without forming the circumferential recess 100, the volume of the sidewall 20 increases (the sidewall 20 becomes thicker), and the amount of heat generation and heat storage increases. In some cases, sufficient performance cannot be obtained. By forming the block 110 on the circumferential recess 100 as in the present embodiment, the effect of suppressing the temperature rise of the rubber can be sufficiently improved.

Further, the outer end (outer surface 111S or 112S) of the block 110 in the tread width direction Tw is located inward of the virtual line Vc1. Since the outer end does not reach (does not protrude) the virtual line Vc1 (that is, the outer surface of the sidewall 20 when the circumferential recess 100 is not provided), damage to the block 110 due to contact with an obstacle can be suppressed. . Therefore, the durability of the block 110 is improved and the cooling effect can be maintained for a long time.

Further, part of the air flow S1 described above becomes an air flow S5 that diverges and collides with the inner wall surface 101 (outer wall surface 102). Since the air flow S5 stirs the air inside the circumferential recess 100, the heat dissipation effect can be improved.

In the cross section described above, the shortest distance X between the block 110 and the virtual line Vc1 is 0 <X ≦ 0.7 Dm where Dm is the maximum depth of the circumferential recess 100. If the shortest distance X is 0 or less, the block 110 protrudes outward from the virtual line Vc1. In this case, as already explained, the durability is lowered. On the other hand, if the shortest distance X is greater than 0.7 Dm, the block 110 is too low to effectively form turbulence, reducing the amount of air taken into the circumferential recess 100 and reducing heat exchange. The cooling effect will be suppressed. Therefore, the shortest distance X is preferably 0 <X ≦ 0.7 Dm. The amount of air taken into the circumferential recess 100 can be increased by maximizing the height h of the block 110 at the position of the maximum depth D of the inner wall surface 101 (outer peripheral edge 100c).

In particular, in an ORR tire having a large outer diameter and a thick sidewall 20, there is a great need to suppress the temperature rise of the rubber constituting the tire 1, but there is a high possibility of the block 110 being damaged due to a rough road. According to the structure mentioned above, the cooling effect by the block 110 is securable also with an ORR tire. That is, according to the pneumatic tire 1 of the present embodiment, it is possible to suppress the temperature rise of the rubber of the sidewall 20 (particularly, the portion near the bead 30) while preventing the block 110 from being damaged.

Further, as the block 110, a first block 111 and a second block 112 are formed along the tire radial direction Td, and the outer peripheral side surface 111a of the first block 111 and the inner peripheral side surface 112a of the second block 112 are It is separated. A turbulent flow is generated in the circumferential recess 100 by the first block 111 and the second block 112. Specifically, the air flow S <b> 1 in the circumferential recess 100 becomes a turbulent flow that repeats adhesion and separation with respect to the inner wall surface 101, the outer wall surface 102, and the bottom surface 103. At this time, the heat of the sidewall 20 (particularly, the portion near the bead 30) is taken away by the air flow S1. That is, heat radiation is promoted starting from the circumferential recess 100, and the temperature rise of the sidewall 20 (particularly, the portion near the bead 30) can be suppressed. As a result, the deterioration of the tire 1 due to the temperature rise of the bead 30 can be suppressed, and the durability of the tire 1 can be improved.

Further, the inner wall surface 101 is formed within a range Hx of 25% or less of the tire height H from the bead heel outer peripheral edge 61a in the cross section described above (see FIGS. 3 and 4A). That is, the inner wall surface 101 which is a curved surface recessed inward is formed in the above-described range Hx near the bead 30. Accordingly, since the inner peripheral edge 100a of the circumferential recess 100 is positioned on the outer peripheral side from the bead heel outer peripheral edge 61a, the side wall 20 (particularly, closer to the bead 30 is not greatly deteriorated when the carcass 40 collapses when the tire 1 is loaded. The temperature rise in the portion (1) can be suppressed. If the inner peripheral edge 100a is positioned on the inner peripheral side from the bead heel outer peripheral edge 61a, the fall of the carcass 40 when the tire 1 is loaded increases, and the durability of the bead 30 is significantly deteriorated.

Further, by forming the inner wall surface 101 within the above-described range Hx, the distance between the high temperature portion inside the tire 1 (particularly, the portion near the bead 30) and the heat radiation surface (the surface of the circumferential recess 100) is reduced. be able to. For this reason, the heat inside the tire 1 can be easily radiated, and the temperature rise of the rubber constituting the tire 1 can be effectively suppressed. If the inner wall surface 101 is formed on the outer peripheral side with respect to the above-described range Hx, the distance between the high temperature portion inside (particularly, the portion closer to the bead 30) and the heat radiating surface (the surface of the circumferential recess 100) is shortened. The temperature rise of the rubber which comprises the tire 1 cannot be suppressed effectively.

In addition, since the bead 30 is firmly fixed to the rim wheel 60 that is a rigid body, a portion near the bead 30 of the sidewall 20 is likely to generate heat due to deformation that falls into the rim flange 61 or friction with the rim flange 61. By forming the circumferential recess 100 in the above-described range Hx, it is possible to effectively suppress the temperature rise in the portion near the bead 30 of the sidewall 20 that easily generates heat.

Further, the maximum depth D of the inner wall surface 101 is set to 15 mm or more and 35 mm or less. When the maximum depth D is deeper than 35 mm, the fall of the carcass 40 when the tire 1 is loaded is remarkably increased. Further, since the heat generation increases due to the increase in the deformation amount, the temperature rise cannot be effectively suppressed, and the durability of the bead 30 also decreases. On the other hand, if the maximum depth D is shallower than 15 mm, the air flow along the outer surface of the sidewall 20 becomes difficult to flow into the circumferential recess 100, and the temperature rise cannot be effectively suppressed.

Further, the above-described curvature radius R2 of the inner wall surface 101 is 50 mm or more in the above-described no-load state. If the radius of curvature R2 is less than 50 mm, the crack resistance of the portion of the side wall 20 near the bead 30 deteriorates due to local concentration of strain on the inner wall surface 101 due to the fall of the carcass 40 when the tire 1 is loaded.

Further, all the first blocks 111 and a part of each of the second blocks 112 are arranged on the inner wall surface 101. Therefore, the air flow smoothly flowing into the circumferential recess 100 along the inner wall surface 101 that is a curved surface that is recessed inward collides with the first block 111 and the second block 112 on the inner wall surface 101, and thus in the circumferential direction. A turbulent flow is effectively generated in the recess 100.

The height h of the block 110 is 3 mm or more and 25 mm or less. Therefore, even if the tire 1 is used within the practical speed range of a construction vehicle tire, the temperature rise of the rubber constituting the tire 1 can be effectively suppressed.

Further, the width w of the block 110 in the tire circumferential direction Tc is not less than 2 mm and not more than 10 mm. If the width w is smaller than 2 mm, the block 110 may vibrate due to the air flow drawn into the circumferential recess 100. In addition, since the rigidity of the block 110 is reduced, the block 110 may be damaged due to traveling on a rough road. On the other hand, if the width w is larger than 10 mm, the volume of the block 110 increases, so the amount of heat generation and the amount of heat storage increase, and the heat dissipation performance may not be sufficiently obtained.

The height h, pitch P, and width w of the block 110 satisfy 1 ≦ (P / h) ≦ 50 and 1 ≦ [(P−w) / w] ≦ 100. By defining the range of P / h, the state of the air flow drawn into the circumferential recess 100 can be roughly organized by P / h. If the pitch P (that is, P / h) is too small, it is difficult for the air flow to adhere to the bottom surface 103. In this case, turbulent flow does not occur in the vicinity of the bottom surface 103, and air stagnates in the vicinity of the bottom surface 103, so that the heat dissipation performance decreases. On the other hand, if the pitch P (that is, P / h) is too large, the interval between the blocks 110 is too wide and close to a state where the blocks 110 are not formed, so that turbulence is hardly generated. Also, (P−w) / w indicates the ratio of the width w to the pitch P. As (Pw) / w becomes smaller, the area of the surface cooled by heat radiation (the area of the bottom surface 103 and the inner wall surface 101 between the blocks 110) decreases. Therefore, in order to ensure the cooling effect due to heat radiation, the minimum value of (P−w) / w is set to 1 (that is, P = 2w and the interval between the blocks 110 = the width w of the blocks).

[Second Embodiment]
As shown in FIG. 8A and FIG. 8B, the circumferential recess 200 is formed on the outer surface of the sidewall 20 also in the tire 2 of the present embodiment. Inside the circumferential recess 200, a first block 211 and a second block 212 are formed at predetermined intervals along the tire circumferential direction Tc. Specifically, the first block 211 is formed on the inner peripheral side, and the second block 212 is formed on the outer peripheral side. In the present embodiment, the first block 211 and the second block 212 are [alternately] formed alternately along the tire circumferential direction Tc. The outer peripheral side surface 211 a of the first block 211 is located inward of the inner peripheral side surface 212 a of the second block 212.

In the tire 2 of the present embodiment, the timing of getting over the first block 211 and the timing of getting over the second block 212 do not coincide with the airflow that has entered the circumferential recess 200. Therefore, the position of the air flow retention region on the back side of the first block 211 and the position of the air flow retention region on the back side of the second block 212 are shifted in the tire circumferential direction Tc, and the retention region is in the tire circumferential direction Tc. Distributed along. For this reason, the air flow that has entered the circumferential recess 200 is likely to be turbulent, heat dissipation is promoted starting from the circumferential recess 200, and the temperature rise of the sidewall 20 (particularly, the portion near the bead 30) can be suppressed. As a result, the deterioration of the tire 2 due to the temperature rise of the bead 30 can be suppressed, and the durability of the tire 2 can be improved.

(Example of change)
As shown in FIG. 9A and FIG. 9B, in the tire 2X which is a modified example of the second embodiment, the circumferential recess 200X is formed on the outer surface of the sidewall 20X. Inside the circumferential recess 200X, a first block 211X and a second block 212X are formed at predetermined intervals along the tire circumferential direction Tc. Specifically, the first block 211X is formed on the inner peripheral side, and the second block 212X is formed on the outer peripheral side. The first blocks 211X and the second blocks 212X are alternately formed along the tire circumferential direction Tc. The outer peripheral side surface 211 a of the first block 211 is located outward from the inner peripheral side surface 212 a of the second block 212. That is, the first block 211X and the second block 212X form an overlapping region R along the tire radial direction Td.

In the tire 2X of the present modified example, an air flow over the first block 211X, an air flow over the second block 212X, and an air flow over both the first block 211X and the second block 212X in the overlapping region R are formed. Is done. Therefore, the air in the staying area on the back side of the first block 211X and the second block 212X is actively disturbed, so the air that has entered the circumferential recess 200X is more likely to be turbulent, and the circumferential recess 200X is the starting point. Heat dissipation is promoted, and the temperature rise of the sidewall 20X (particularly, the portion near the bead 30) can be suppressed. As a result, the deterioration of the tire 2X due to the temperature rise of the bead 30 can be suppressed, and the durability of the tire 2X can be improved.

[Third Embodiment]
As shown in FIG. 10A and FIG. 10B, the circumferential recess 300 is formed on the outer surface of the sidewall 20 also in the tire 3 of the present embodiment. Similar to the first embodiment, the circumferential recess 300 is located between the inner wall surface 301 located on the inner circumferential side, the outer wall surface (not shown) located on the outer circumferential side, and the inner wall surface 401 and the outer wall surface. And a bottom surface 303. A first block 311, a second block 312 and a third block 313 are formed inside the circumferential recess 300. Specifically, the first block 311 is formed on the inner peripheral side, and the second block 312 is formed on the outer peripheral side. The first block 311 and the second block 312 are formed on a straight line along the tire radial direction Td. The outer peripheral side surface 311 a of the first block 311 is located inward of the inner peripheral side surface 312 a of the second block 312.

The width w in the tire circumferential direction Tc and the height h in the tread width direction Tw of the third block 313 are the same as the width w in the tire circumferential direction Tc and the height h in the tread width direction Tw of the second block 312, respectively. Further, the third block 313 is formed closer to one first block 311 (or the second block 312) than an intermediate point between the adjacent first blocks 311 (or the second block 312). A distance L3 in the tire circumferential direction Tc between 313 and the first block 311 (or the second block 312) is 5% to 10% of the pitch P.

The inner peripheral side surface 313 c of the third block 313 is located inward of the outer peripheral side surface 311 a of the first block 311, and the outer peripheral side surface 313 b of the third block 313 is the inner peripheral side of the second block 312. It is located outward from the side surface 312a. That is, the third block 313 forms an overlapping region with the outer peripheral side portion of the first block 311, and also forms an overlapping region with the inner peripheral side portion of the second block 312.

In the tire 3 of the present embodiment, the third block 313 is further formed, so that the air that has entered the circumferential recess 300 gets over not only the first block 311 and the second block 312 but also the third block 313. Since it flows, it repeatedly adheres to and peels from the inner wall surface 301 and the bottom surface 303, resulting in larger turbulence. The air that has entered the circumferential recess 300 flows away from the heat accumulation area of the air flow on the back side of the first block 311, the second block 312, and the third block 313. As a result, the temperature rise of the bead 30 can be more effectively suppressed.

The flow colliding with the third block 313 is divided into a flow over the third block 313 and a flow toward the outer peripheral side surface 313b and the inner peripheral side surface 313c. Here, as described above, the inner peripheral side surface 313c of the third block 313 is located inward of the outer peripheral side surface 311a of the first block 311 and the outer peripheral side surface 313b of the third block 313 is The second block 312 is located outward from the inner peripheral side surface 312a. Accordingly, the air flowing into the circumferential recess 300 is actively disturbed by the flow toward the outer peripheral side surface 313b and the inner peripheral side surface 313c because the air in the back region of the first block 311 and the second block 312 is actively disturbed. Is more likely to be turbulent, heat dissipation is promoted starting from the circumferential recess 300, and the temperature rise of the sidewall 20 (particularly, the portion near the bead 30) can be suppressed. As a result, the deterioration of the tire 3 due to the temperature rise of the bead 30 can be suppressed, and the durability of the tire 3 can be improved.

[Comparison evaluation]
Comparative evaluation was performed using tires of conventional examples, comparative examples, and examples.

(1) Evaluation method Tests were conducted to evaluate the side wall temperature rise suppression effect and the block durability performance. In the conventional tire, as shown in FIG. 11A, the circumferential recess and the block are not formed. In the tire of Comparative Example 1, as shown in FIG. 11B, blocks are formed on the outer surface of the sidewall, but no circumferential recess is formed. In the tire of Comparative Example 2, the circumferential recess and the block are formed, but the block protrudes outward from the imaginary line in the cross section described above. In the tire of the example, a circumferential recess and a block are formed, and the block does not protrude outward from the imaginary line. The configurations of the conventional example, the comparative example, and the example are also shown in the following [Table 1].

In the test, three tires of all types were prepared, and all the tires were leaned against the wall and left for one week. Thereafter, the tire was assembled to the TRA regular rim wheel 60 and mounted on the vehicle, and a normal load and a normal internal pressure were applied to the tire. Further, the vehicle is run for 24 hours, a thermoelectric body is inserted into a narrow hole formed in advance at a position 40 mm on the outer peripheral side of the rim flange 61 in the tire radial direction Td, and 5 mm in the tread width direction Tw from the carcass 40. The temperature at the outer location was measured. The temperature was measured at six locations at regular intervals along the tire circumferential direction Tc for each tire. For the evaluation, an average value of six temperatures was obtained, and the temperature difference from the average value of the conventional example was performed.

The other conditions for the evaluation test are as follows. Tire size: 59 / 80R63, tire type: heavy duty tire, vehicle: 320 ton-dump truck, vehicle running speed: 15 km / h, running time: 24 hours. Further, the block durability performance was evaluated by confirming the presence or absence of breakage after the running test for the pneumatic tires according to Comparative Example 2 and Examples. The evaluation numerical value for the block durability performance is indicated by an index [index number] with the pneumatic tire according to Comparative Example 2 as 100.

(2) Evaluation results The evaluation results will be described with reference to [Table 1].

As shown in [Table 1], according to the tire of the example, a better temperature rise suppressing effect than that of the tire of the conventional example and the comparative example 1 can be obtained. Moreover, according to the tire of an Example, the temperature rise inhibitory effect comparable as the tire of the comparative example 2 is acquired. The block durability performance of the tire of the example is significantly improved as compared with the tire of Comparative Example 2. That is, the tire of the example has a smaller block height than the tire of the comparative example 2, so that the effect of generating turbulence is slightly reduced, but the durability of the block is improved, so that the cooling effect lasts longer.

[Fourth Embodiment]
As shown in FIG. 12A and FIG. 12B, the circumferential recess 400 is formed on the outer surface of the sidewall 20 also in the tire 4 of the present embodiment. Similar to the first embodiment, the circumferential recess 400 is positioned between the inner wall surface 401 located on the inner circumferential side, the outer wall surface (not shown) located on the outer circumferential side, and the inner wall surface 401 and the outer wall surface. And a bottom surface 403. Inside the circumferential recess 400, a first block 411, a second block 412 and a third block 413 are formed at predetermined intervals along the tire circumferential direction Tc. Specifically, the first block 411 is formed on the inner peripheral side, and the second block 412 is formed on the outer peripheral side. The first block 311 and the second block 312 are formed on a straight line along the tire radial direction Td. The outer peripheral side surface 311 a of the first block 311 is located inward of the inner peripheral side surface 312 a of the second block 312.

The third block 413 is provided in the middle of the adjacent first blocks 411 (or second blocks 412). That is, the pair of the first block 411, the second block 412 and the third block 413 are alternately formed along the tire circumferential direction Tc. The length of the third block 413 in the tire radial direction Td is equal to the distance from the inner peripheral end of the first block 411 to the outer peripheral end of the second block 412.

In the pneumatic tire 4 according to the present embodiment, the turbulent flow generated by the first block 411 and the second block 412 further passes over the third block 413, and a larger turbulent flow is formed. As a result, heat dissipation is promoted starting from the circumferential recess 400, and the temperature rise of the sidewall 20 (particularly, the portion near the bead 30) can be suppressed.

[Fifth Embodiment]
As shown in FIG. 13A and FIG. 13B, also in the tire 5 of the present embodiment, a circumferential recess 500 is formed on the outer surface of the sidewall 20. Similar to the first embodiment, the circumferential recess 500 is positioned between the inner wall surface 501 located on the inner circumferential side, the outer wall surface (not shown) located on the outer circumferential side, and the inner wall surface 501 and the outer wall surface. And a bottom surface 503. A first block 511, a second block 512, a third block 513, and a fourth block 514 are formed inside the circumferential recess 500. Specifically, the first block 311 is formed on the inner peripheral side, and the second block 312 is formed on the outer peripheral side. The first block 511 and the second block 512 are formed on a straight line along the tire radial direction Td. The outer peripheral side surface 511 a of the first block 511 is positioned inward from the inner peripheral side surface 512 a of the second block 512.

Two pairs of the first block 511 and the second block 512 are provided at equal intervals between the adjacent third blocks 513. The length of the third block 413 in the tire radial direction Td is equal to the distance from the inner peripheral end of the first block 411 to the outer peripheral end of the second block 412. Furthermore, in the tire 5 of the present embodiment, a fourth block 514 extending in the tire circumferential direction Tc is added to the tire 4 of the fourth embodiment described above.

The fourth block 514 passes between the first block 511 and the second block 512 in the tire circumferential direction Tc, and continuously extends over the entire circumference of the tire 5. The fourth block 514 intersects with all the third blocks 513. Accordingly, the circumferential recess 500 is divided into the inner periphery recess 500X and the outer periphery recess 500Y by the fourth block 514. That is, the first block 511 is formed in the inner circumferential recess 500X, and the second block 512 is formed in the outer circumferential recess 500Y.

The distance L4a between the outer peripheral side surface 511a of the first block 511 and the inner peripheral side edge 514a of the fourth block 514 is 15% to 30% of the pitch P of the first block 511. The distance L4b between the inner peripheral side surface 512a of the second block 512 and the outer peripheral side edge 514b of the fourth block 514 is 15% to 30% of the pitch P of the second block 512.

The first block 511, the second block 512, and the third block 513 are arranged at appropriate intervals according to the size of the tire 5 and the type of vehicle. Further, the interval La and the width from the inner peripheral edge of the circumferential recess 500 of the fourth block 514 are also set to appropriate values according to the size of the tire 5 and the type of vehicle. In this embodiment, two pairs of the first block 511 and the second block 512 are provided between the adjacent third blocks 513, but the first block 511 provided between the adjacent third blocks 513 is provided. The number of pairs of the second blocks 512 can be changed as appropriate.

In the tire 5 of this embodiment, the turbulent flow generated by the first block 511 or the second block 512 further passes over the third block 413 and the fourth block 514, and a larger turbulent flow is formed. Here, since the turbulent flow goes over the fourth block 514, turbulent flow is formed not only in the tire circumferential direction Tc but also in the tire radial direction Td. As a result, heat dissipation is promoted starting from the circumferential recess 500, and the temperature rise of the sidewall 20 (particularly, the portion near the bead 30) can be suppressed.

[Sixth Embodiment]
As shown in FIG. 14, also in the tire of this embodiment, a circumferential recess is formed on the outer surface of the sidewall. Similar to the first embodiment, the circumferential recess has an inner wall surface located on the inner circumference side, an outer wall surface located on the outer circumference side, and a bottom surface located between the inner wall surface and the outer wall surface. A first block 711 and a second block 712 are formed inside the circumferential recess. In the present embodiment, the length of the first block 711 in the tire radial direction Td and the length of the second block 712 in the tire radial direction Td are alternately changed. According to the present embodiment, the air flow passing between the first block 711 and the second block 712 collides with the next first block 711 or the second block 712, so that turbulence is more likely to be generated. As a result, the temperature rise of the sidewall (particularly, the portion near the bead) can be suppressed.

[Seventh Embodiment]
As shown in FIG. 15, also in the tire of this embodiment, a circumferential recess is formed on the outer surface of the sidewall. Similar to the first embodiment, the circumferential recess 800 is positioned between the inner wall surface 801 located on the inner circumferential side, the outer wall surface (not shown) located on the outer circumferential side, and the inner wall surface 801 and the outer wall surface. And a bottom surface 803. A first block 811 and a second block 812 are formed inside the circumferential recess 800. In the present embodiment, the inner peripheral end of the first block 811 is separated from the inner peripheral edge 800a of the circumferential recess. Accordingly, since an air flow is generated between the first block 811 and the inner peripheral edge 800a, a turbulent flow is further easily generated. As a result, the temperature rise of the sidewall (particularly, the portion near the bead) can be suppressed.

[Other Embodiments]
Further, the blocks formed inside the circumferential recess may be arranged as shown in FIGS. 16 (a) to 16 (e). As shown in FIG. 16A, the first block and the second block may be formed on a curve, not formed on a straight line along the tire radial direction Td. Alternatively, as shown in FIGS. 16B to 16D, the first block and the second block may be inclined with respect to the tire radial direction Td. Further, as shown in FIG. 16 (e), the length of the first block in the tire radial direction Td and the length of the second block in the tire radial direction Td may be different from each other.

Further, the angle formed by the inner peripheral side surface and the outer peripheral side surface of the block formed inside the circumferential recess and the outer surface (inner side surface, outer side surface, and bottom surface) of the circumferential recess is not limited. For example, the inner peripheral side surface of the first block may be perpendicular to the outer surface of the circumferential recess, and the outer peripheral side surface of the second block may be perpendicular to the outer surface of the circumferential recess. Moreover, the inner peripheral side surface and the outer peripheral side surface of the block may be inclined with respect to the tire circumferential direction Tc instead of being parallel to the tire circumferential direction Tc.

The tire of the above embodiment was a pneumatic tire [pneumatic tire] filled with air, nitrogen gas, or the like. The tire of the present invention may be a run flat tire (a kind of pneumatic tire) or a solid tire that is not filled with gas.

The entire contents of Japanese Patent Application No. 2013-163018 (filed on Aug. 6, 2013) are incorporated herein by reference. Although the present invention has been described above with reference to embodiments of the present invention, the present invention is not limited to the above-described embodiments. The scope of the invention is determined in light of the claims. In addition, the features of the above-described embodiments and modifications can be employed in appropriate combinations.

Claims (11)

A tire having a tread in contact with a road surface and a sidewall continuous with the tread,
A circumferential recess formed on the outer surface of the sidewall along the tire circumferential direction and recessed inward along the tread width direction; and
A block formed inside the circumferential recess and projecting outward along the tread width direction.
The sidewall has a rim-side outer surface formed from a bead heel outer periphery where the sidewall separates from a rim flange to which the tire is attached to an inner periphery of the circumferential recess in a cross section including the rotation axis of the tire. And
In the cross section, a tire in which the block does not reach a virtual line obtained by extending the outer surface on the rim side from the inner peripheral edge to the outer peripheral side. The tire according to claim 1,
The outer surface on the rim side is on a first arc curve centered on a point located inside the tread width direction in the cross section,
The tire in which the imaginary line is a line obtained by extending the first circular arc curve from the inner peripheral edge to the outer peripheral side in the cross section. The tire according to claim 1 or 2,
In the cross section, a tire in which 0 <X ≦ 0.7 Dm, where X is a shortest distance between the block and the virtual line, and Dm is a maximum depth of the circumferential recess with respect to the virtual line. The tire according to any one of claims 1 to 3,
The circumferential recess has an inner wall surface formed from the inner peripheral edge to the bottom surface of the circumferential recess;
The tire in which the height of the block is maximized at the position of the outer peripheral edge of the inner wall surface in the cross section. The tire according to claim 4,
In the cross section, the tire has a maximum depth of 15 mm to 35 mm with respect to the virtual line. The tire according to claim 4 or 5,
The tire according to the cross section, wherein the inner wall surface forms a curve that is recessed inward in the tread width direction from the inner peripheral edge. The tire according to claim 4 or 5,
The tire according to the cross section, wherein the inner wall surface is on a second arc curve centered on a point located outside in the tread width direction. The tire according to any one of claims 1 to 7,
A tire having a height of the block of 3 mm to 25 mm. The tire according to any one of claims 1 to 8,
The blocks are arranged at predetermined pitches in the tire circumferential direction,
A tire in which a width of the block in the tire circumferential direction is 2 mm to 10 mm. The tire according to claim 9, wherein
When the height of the block is h, the predetermined pitch is P, and the width of the block is w, 1 ≦ (P / h) ≦ 50 and 1 ≦ [(P−w) / w] A tire that satisfies ≦ 100. The tire according to any one of claims 4 to 10,
A tire, wherein at least a part of the block is disposed on the inner wall surface.

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