JP7151326B2 - pneumatic tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pneumatic tire, and more specifically to a pneumatic tire provided with a two-dimensional code stamped on the sidewall portion of the tire.

In recent years, it has been proposed to provide a two-dimensional code in which information is recorded on the sidewall portion of a pneumatic tire (hereinafter also simply referred to as a tire). Since the two-dimensional code can contain more information than the one-dimensional code, various information can be contained in the two-dimensional code to manage tires. It has been proposed to provide a two-dimensional code composed of a pattern of dark and light elements on the sidewall portion by imprinting a predetermined pattern of dot holes on the sidewall portion (Patent Document 1).

The two-dimensional code, which is formed by stamping a predetermined pattern of dot holes on the sidewall portion, does not disappear unless the sidewall portion is worn, so that tire management can be performed effectively.

WO2005/000714

In a pneumatic tire provided with a plurality of dot holes for such a two-dimensional code, the two-dimensional code can be read when the tire is brand new. In some cases, code reading was degraded. Reading of a two-dimensional code is reading of a two-dimensional code by a two-dimensional code reader, for example, a mobile terminal, and poor reading means that reading fails more often. The two-dimensional code provided on the pneumatic tire is used by reading the information recorded on the two-dimensional code while the tire is in use. As a result, when the tire is used for a long time, cracks occur and develop in the dot holes of the two-dimensional code, resulting in irregularities on the surface of the two-dimensional code. I don't like doing it. For this reason, it is preferable to suppress deterioration in readability of the two-dimensional code during long-term use of the tire.

On the other hand, for pneumatic tires, the carcass ply is attached to the inside of the tire in order to enable the pneumatic tire to run flat (when the air pressure is low and the air pressure is close to zero). In many cases, a run-flat reinforcing rubber is provided on each of the sidewall portions of the pneumatic tire so as to cover the tire. In such a pneumatic tire, a highly rigid rubber is used as the run-flat reinforcing rubber in order to suppress deformation of the side rubber. Therefore, deformation of the side rubber of the pneumatic tire is suppressed not only when the tire is runflat, but also when the tire is filled with air. However, since the run-flat reinforcing rubber is not a reinforcing rubber having a uniform thickness but has a distribution of thickness, the deformation of the side rubber tends to be concentrated in a thin portion. For this reason, marking a two-dimensional code in the same place as a pneumatic tire without run-flat reinforcing rubber is not preferable from the viewpoint of suppressing deterioration in readability of the two-dimensional code during long-term use of the pneumatic tire. In some cases.

Accordingly, the present invention provides a pneumatic tire having a run-flat reinforcing rubber that suppresses deformation of the side rubber when the pneumatic tire is run-flat. The purpose is to provide a set of tires.

One aspect of the present invention is a pneumatic tire. The pneumatic tire is
a pair of annular bead cores;
at least one toroidal carcass ply wound around the pair of bead cores and provided between the pair of bead cores;
a side rubber provided on each sidewall portion of the pneumatic tire so as to cover the carcass ply from the outside of the tire;
a run-flat reinforcing rubber provided on each sidewall portion of the pneumatic tire so as to cover the carcass ply from the inside of the tire and suppressing deformation of the side rubber when the pneumatic tire is run-flat.
On the surface of the sidewall portion, a two-dimensional code is provided in which a dot pattern is formed by two types of dark and light elements that are formed to be mutually identifiable by surface unevenness,
The two-dimensional cord range in the tire radial direction where the two-dimensional cord is provided is the tire made of the run-flat reinforcing rubber when the pneumatic tire is mounted on a normal rim and the pneumatic tire is filled with a normal internal pressure. Height along the tire radial direction of the run-flat reinforcing rubber when the pneumatic tire is mounted on a regular rim and filled with the regular internal pressure from the radially inner end and the tire radially outer end It is located in a range separated from H by 10% or more.

The run-flat reinforcing rubber defined on a normal line passing through the center point in the tire radial direction of the two-dimensional cord range in which the two-dimensional cord is provided and along the normal direction of the surface of the sidewall portion at the center point. is preferably 20% or more of the maximum thickness Tmax of the run-flat reinforcing rubber.

A ratio (T/L) of the thickness T of the run-flat reinforcing rubber to the distance L from the center point defined on the normal line to the carcass ply is preferably 0.6 or more.

The run-flat reinforcing rubber preferably has a rubber hardness of 75 to 90 according to JIS K-6253.

It is preferable that the two-dimensional code is provided on a smooth surface without ridges.

It is preferable that the two-dimensional cord area is positioned radially outward or inward in the tire radial direction from the end of the folded portion of the carcass ply wound around the bead core.

A bead filler rubber is sandwiched between a carcass ply before folding around the bead core of the carcass ply and a folded portion after the carcass ply is wound, and extends outward in the tire radial direction of the bead core,
It is preferable that the two-dimensional cord range in which the two-dimensional cord is provided is positioned radially outward or inwardly away from the radially outer end of the bead filler rubber in the tire radial direction.

The two-dimensional code range in which the two-dimensional code is provided is defined on a normal line passing through the center point of the two-dimensional code range in the tire radial direction and along the normal direction of the surface of the sidewall portion at the center point. It is preferable that the thickness of the side rubber to be formed is 2.5 mm or more.

The two-dimensional cord range, in which the two-dimensional cord is provided, is spaced outward or inward in the tire radial direction, or on both sides in the tire circumferential direction from a joint line where two rubbers are joined to each other on the surface of the sidewall portion. preferably in position.

Along the tire radial direction from the innermost position of the bead core in the tire radial direction to the maximum outer diameter position of the tire when the pneumatic tire is mounted on a regular rim and the pneumatic tire is filled with a regular internal pressure When the cross-sectional height is SH, when the pneumatic tire is mounted on a regular rim and the pneumatic tire is filled with regular internal pressure, the innermost position of the bead core in the tire radial direction is two The distance H along the tire radial direction to the center point of the dimension code in the tire radial direction is preferably 70% or less of the cross-sectional height SH.

It is preferable that the two-dimensional cord is provided on each of the sidewall portions on both sides of the pneumatic tire in the tire width direction.

According to the pneumatic tire described above, it is possible to suppress deterioration in readability of the two-dimensional code during long-term use of the pneumatic tire.

It is a figure showing an example of composition of a pneumatic tire of one embodiment. (a), (b) is a figure explaining the example of the two-dimensional code of one Embodiment. It is a figure explaining the example of the arrangement position of the two-dimensional code in one embodiment. FIG. 11 is a diagram illustrating an example of arrangement positions of a two-dimensional code in another embodiment;

A pneumatic tire according to one embodiment will be described in detail below.
In this specification, the tire width direction is a direction parallel to the rotation axis of the pneumatic tire. The tire width direction outer side is the side away from the tire equator line CL (see FIG. 1) representing the tire equatorial plane in the tire width direction. Further, the inner side in the tire width direction is the side closer to the tire equator line CL in the tire width direction. The tire circumferential direction is the direction in which the pneumatic tire rotates about the rotation axis. The tire radial direction is a direction perpendicular to the rotation axis of the pneumatic tire. The outer side in the tire radial direction refers to the side away from the rotating shaft. Moreover, the inner side in the tire radial direction refers to the side closer to the rotating shaft.
In addition, the tire inner side refers to the side of the tire inner surface facing the tire cavity area surrounded by the tire and the wheel and filled with air at a predetermined pressure, and the tire outer side refers to the tire outer surface side in contact with the atmosphere.

The two-dimensional code referred to in this specification is a matrix display type code that has information in two directions, as opposed to a one-dimensional code (bar code) that has information only in the horizontal direction. As a two-dimensional code, for example, QR code (registered trademark), Data Matrix (registered trademark), Maxicode, PDF-417 (registered trademark), 16K code (registered trademark), 49 code (registered trademark), Aztec code (registered trademark) ), SP Code(R), VeriCode(R), and CP Code(R).

(pneumatic tire)
FIG. 1 is a diagram showing an example of the configuration of a pneumatic tire 10 (hereinafter simply referred to as tire 10) according to one embodiment. FIG. 1 shows a profile section on one side in the tire width direction with respect to the tire equator line CL.

The tire 10 includes a tread portion 10T having a tread pattern, a pair of bead portions 10B on both sides in the tire width direction, and a pair of sides provided on both sides of the tread portion 10T and connected to the pair of bead portions 10B and the tread portion 10T. and a wall portion 10S. The tread portion 10T is a portion that contacts the road surface. The sidewall portions 10S are portions provided so as to sandwich the tread portion 10T from both sides in the tire width direction. The bead portion 10B is a portion connected to the sidewall portion 10S and positioned radially inward of the sidewall portion 10S.

The tire 10 has a carcass ply 12, a belt 14, and a bead core 16 as skeleton materials, and a tread rubber 18, a side rubber 20, a bead filler rubber 22, and a bead filler around these skeleton materials. It mainly has reinforcing rubber 23 , rim cushion rubber 24 , run-flat reinforcing rubber 25 and inner liner rubber 26 .

The carcass ply 12 is composed of a carcass ply material in which organic fibers are coated with rubber and wound between a pair of annular bead cores 16 to form a toroidal shape. The carcass ply 12 is wound around the bead core 16 and extends outward in the tire radial direction. A belt 14 composed of two belt members 14a and 14b is provided outside the carcass ply 12 in the tire radial direction. The belt 14 is made of a belt material in which a rubber-coated steel cord is arranged at a predetermined angle, for example, 20 to 30 degrees, with respect to the tire circumferential direction. is longer than the width of the upper belt material 14b in the tire width direction. The steel cords of the two layers of belt materials 14a and 14b extend obliquely in opposite directions with respect to the tire circumferential direction. For this reason, the belt materials 14a and 14b are interlaced layers, which suppress the expansion of the carcass ply 12 due to the filled air pressure.

A tread rubber 18 is provided outside the belt 14 in the tire radial direction, and side rubbers 20 are connected to both ends of the tread rubber 18 to form sidewall portions 10S. A rim cushion rubber 24 is provided at the inner end in the tire radial direction of the side rubber 20 and contacts the rim on which the tire 10 is mounted. On the outside of the bead core 16 in the tire radial direction, it is sandwiched between the portion of the carcass ply 12 before being wound around the bead core 16 and the portion of the carcass ply 12 that is wound around the bead core 16 and folded back. A bead filler rubber 22 is provided. The bead filler rubber 22 extends outward in the tire radial direction from the bead core 16 side along the carcass ply 12 . The bead filler reinforcing rubber 23 is provided outside the folded carcass ply 12 in the tire width direction along the carcass ply 12 . A side rubber 20 or a rim cushion rubber 24 is provided outside the bead filler reinforcing rubber 23 in the tire width direction.
The run-flat reinforcing rubber 25 is provided on each sidewall portion 10S of the pneumatic tire 10 so as to cover the carcass ply 12 from the inside of the tire. The run-flat reinforcing rubber 25 suppresses deformation of the side rubber 20 when the pneumatic tire 10 is run-flat, and is made of rubber with high rigidity. The thickness of the run-flat reinforcing rubber 25 is thin on the inner side and the outer side in the tire radial direction, and the thickness is maximized near the maximum width position of the tire. An inner liner rubber 26 is provided on the inner surface of the tire 10 facing the air-filled tire cavity region surrounded by the tire 10 and the wheel of the run-flat reinforcing rubber 25 .
In addition, between the belt material 14b and the tread rubber 18, a two-layer belt cover 30 made of organic fibers coated with rubber is provided to cover the belt 14 from the outside in the tire radial direction. The belt cover 30 may be provided as required, and is not essential. The number of layers of the belt cover 30 is also not limited to two layers, and may be one layer, three layers, or the like.
A two-dimensional cord 40 is provided on the surface of the sidewall portion 10S of the tire 10 as described above. In FIG. 1, the arrangement position of the two-dimensional code 40 is indicated by a thick line.

(Sidewall part 10S, two-dimensional code 40)
FIG. 2(a) is a diagram illustrating an example of the two-dimensional code 40 of one embodiment provided on the surface of the sidewall portion 10S of the tire 10. FIG. FIG. 2(b) is a diagram illustrating an example of surface irregularities of the two-dimensional code 40. As shown in FIG.
A two-dimensional code 40 is imprinted on one surface of the sidewall portion 10S by irradiation with a laser beam. The two-dimensional code 40 is formed by forming a dot pattern with two kinds of dark and light elements formed so as to be mutually identifiable by unevenness of the surface. The two-dimensional code 40 is formed by converging the laser beam on the surface of the sidewall portion 10S to concentrate the energy, locally heating the rubber at the place to be marked, sublimating it, and marking a plurality of minute dot holes 40a on the surface. It is a pattern formed by As shown in FIG. 2B, the dot holes 40a that form the dot pattern have a cross section that gradually decreases along the depth direction. In the example shown in FIG. 2B, the shape of the hole wall surface when the dot hole 40a is cut along the plane passing through the central axis of the hole extending in the depth direction of the dot hole 40a is straight. It may be a convex or concave curve towards the opening. The dot holes 40a are circular or rectangular holes on the tread surface. In the case of circular dot holes 40a, the diameter is, for example, 0.1 to 1.0 mm, and the hole depth D is, for example, 0.3 to 1.0 mm. The hole wall angle θ of the dot hole 40a is, for example, 10 to 50 degrees.

In the two-dimensional code 40, one dot hole (recess) is printed in the unit cell area of the dark element among the unit cells that divide the dark and light elements of the two-dimensional code. No dot holes (recesses) are provided in the unit cell regions of the light elements among the unit cells. That is, the two-dimensional code 40 corresponds to a plurality of rectangular unit cell areas of the same size divided into a grid pattern, and each dot hole (concave portion) forms one unit cell area with a high density element. , dot holes (recesses) are imprinted. In FIG. 2(a), the dark element area of the unit cell area is indicated by a blackened area.

The two-dimensional code 40 shown in FIG. 2(a) is a QR code (registered trademark) and has a dot pattern area 42 in which a dot pattern is formed with two types of shading elements. Around the dot pattern area 42, a blank area 44 made up of light elements surrounded by light elements among the density elements is provided. (In FIG. 2(a), a frame line is shown in order to clarify the outer edge of the blank area 44). The width w of the blank area 44 is preferably 4 to 5 times the dimension size of the unit cell area in the dot pattern area 42, for example. For example, blank area 44 is preferably 15-25% of the width of dot pattern area 42 .
Since the two-dimensional code 40 shown in FIG. 2(a) is a QR code (registered trademark), the dot pattern area 42 includes a data cell area 42a displaying the data cells of the QR code (registered trademark) and a cutout symbol. and a clipped symbol area 42b.

In the example shown in FIG. 2B, the dot hole 40a forming the dot pattern of the two-dimensional code 40 has a hole cross section that gradually becomes smaller along the depth direction and forms a sharp angular shape at the hole bottom. there is However, the hole bottom need not have a sharp angular shape, and may have a planar shape, for example.

The arrangement position of the two-dimensional cord 40 provided on each of the sidewall portions 10S is restricted by providing the run-flat reinforcing rubber 25. As shown in FIG. Specifically, the two-dimensional cord range in the tire radial direction in which the two-dimensional cord 40 is provided extends from the radially inner end of the run-flat reinforcing rubber 25 and the radially outer end of the run-flat reinforcing rubber 25 to the tire of the run-flat reinforcing rubber 25. It is located in a range separated by 10% or more of the height H along the radial direction. The position of the radially inner end of the run-flat reinforcing rubber 25, the position of the radially outer end of the tire, and the height H of the run-flat reinforcing rubber 25 along the tire radial direction are determined when the tire 10 is mounted on a regular rim. and is determined from the tire profile cross-sectional shape when the tire cavity region of the tire 10 is filled with a normal internal pressure. Here, the regular rim is a "standard rim" defined by JATMA, a "design rim" defined by TRA, or a "measuring rim" defined by ETRTO. The regular internal pressure is the maximum air pressure specified by JATMA, the maximum value specified by TRA "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", or the "INFLATION PRESSURES" specified by ETRTO.

FIG. 3 is a diagram for explaining an example of the arrangement position of the two-dimensional code 40. As shown in FIG. FIG. 3 shows the height H along the tire radial direction of the run-flat reinforcing rubber 25, and 10% of the height H (distance H1) indicates a preferred range R1 of the two-dimensional code range in the radial direction of the tire where the two-dimensional code 40 is provided and the distant position. The provision of the two-dimensional code 40 within the range R1 means that even a part of the two-dimensional code 40 is not located outside the range R1. Here, when the two-dimensional code 40 is a QR code (registered trademark), it means that the dot pattern area 42 is provided within the range R1, and the blank area 44 may also be provided within the range R1. preferable.

The reason why the two-dimensional cord 40 is provided in the range R1 at a distance of 10% or more of the height H from the radially inner end and the radially outer end of the run-flat reinforcing rubber 25 is as follows. . That is, since the location outside the range R1 is close to the tire radially outer end or the tire radially inner end of the run-flat reinforcing rubber 25, the strain due to the bending deformation of the tire 10 is large. If the two-dimensional cord 40 is provided in a place where this strain is large, cracks are likely to occur in the bottom of the dot holes 40a due to long-term use of the tire 10, and the surface of the two-dimensional cord 40 becomes uneven as the crack progresses. As a result, the degree of gradation of the gradation elements of the two-dimensional code 40 is reduced, and the readability of the two-dimensional code 40 is deteriorated. For this reason, a range R1 separated by 10% or more of the height H along the tire radial direction of the run-flat reinforcing rubber 25 from the radially inner end and the radially outer end of the run-flat reinforcing rubber 25 is formed two-dimensionally. Code 40 is provided.

According to one embodiment, the thickness T (see FIG. 3) of the run-flat reinforcing rubber 25 in the two-dimensional cord range where the two-dimensional cord 40 is provided is 20% or more of the maximum thickness Tmax of the run-flat reinforcing rubber 25. Yes, preferably. Here, the thickness T of the run-flat reinforcing rubber 25 passes through the tire radial direction center point M (see FIG. 3) of the two-dimensional cord range, and extends along the normal direction of the surface of the sidewall portion 10S at the center point M. It refers to the thickness of the run-flat reinforcing rubber 25 defined on the normal line. Further, the maximum thickness Tmax of the run-flat reinforcing rubber 25 is the maximum thickness of the run-flat reinforcing rubber 25 defined on the normal line extending in the normal direction from each position on the surface of the sidewall portion 10S such as the side rubber 20. refers to thickness. By limiting the position of the two-dimensional code range in this way, it is possible to prevent cracks from occurring in the bottom of the dot holes 40a due to long-term use of the tire 10, and to prevent the surface of the two-dimensional code 40 from becoming uneven. Thus, deterioration in readability of the two-dimensional code 40 can be suppressed. More preferably, the thickness T of the run-flat reinforcing rubber 25 in the two-dimensional code range where the two-dimensional code 40 is provided is 40% or more of the maximum thickness Tmax.

Further, according to one embodiment, the run-flat reinforcing rubber 25 for the distance L ( FIG. 3 ) from the center point M defined on the normal line passing through the tire radial direction center point M of the two-dimensional cord range to the carcass ply 12 The thickness T ratio (T/L) is preferably 0.6 or more. More preferably, the ratio (T/L) is 1.0 or more. At a position where the ratio (T/L) is 0.6 or more, the thickness T of the run-flat reinforcing rubber 25 is larger than the side rubber 20, the bead filler reinforcing rubber 23, the rim cushion rubber 24, etc. on the tire outer side of the carcass ply 12. At this position, the strain of the side rubber 20 due to the bending deformation of the tire 10 is small. Therefore, cracks are less likely to occur at the bottom of the dot holes 40a, and crack propagation is suppressed, so that deterioration in readability of the two-dimensional code 40 can be suppressed. The upper limit of the ratio (T/L) is, for example, 1.8.

According to one embodiment, the run-flat reinforcing rubber 25 preferably has a rubber hardness of 75-90 according to JIS K-6253. Rubber hardness is measured with an A-type durometer at a temperature of 20° C., for example. By using the run-flat reinforcing rubber 25 having such a rubber hardness for the tire 10, the run-flat running of the tire 10 becomes possible, and in addition to the readability of the two-dimensional code 40 after running in an air-filled state, the run-flat running is improved. As for the readability of the two-dimensional code 40 later, it is possible to suppress the deterioration of the readability.

According to one embodiment, the two-dimensional code 40 is preferably provided on a smooth surface without ridges in order to improve readability of the two-dimensional code 40 . The smooth surface may be a flat surface or a curved surface.

According to one embodiment, the two-dimensional cord range in the tire radial direction in which the two-dimensional cord 40 is provided is from the end of the folded portion after winding around the bead core 16 of the carcass ply 12 in the tire radial direction. Preferably, they are spaced radially outwardly or inwardly. Since the rigidity of the sidewall portion 10S changes abruptly near the end of the folded portion of the carcass ply 12, the strain of the rubber of the sidewall portion 10S due to the bending deformation of the tire 10 is large near the end of the folded portion. For this reason, if the two-dimensional cord 40 is provided near the end of the folded portion of the carcass ply 12, cracks will occur at the bottom of the dot holes 40a, and the cracks will develop further. readability is lowered, which is not preferable. From this point, it is preferable to position the two-dimensional cord range at a position away from the end of the folded portion of the carcass ply 12 in the tire radial direction outside or inside in the tire radial direction. Furthermore, the distance between the end of the folded portion of the carcass ply 12 and the edge of the two-dimensional cord 40 closest to the end is 20% or more of the length of the two-dimensional cord 40 along the tire radial direction, and further , is preferably 40% or more.

Further, according to one embodiment, the two-dimensional cord range in the tire radial direction in which the two-dimensional cord 40 is provided extends from the tire radially outer end of the bead filler rubber 22 to the tire radially outer or inner side in the tire radial direction. A remote location is preferred. When the tire 10 is flexurally deformed, the end of the bead filler rubber 22 becomes a bending point where the deformation of the rubber of the sidewall portion 10S differs between the outer region and the inner region in the tire radial direction with this end as a boundary. A large strain is likely to occur on the surface of the rubber at the end of the filler rubber 22 in the tire radial direction. If the two-dimensional code 40 is provided in this portion, the dot holes 40a of the two-dimensional code 40 are likely to be cracked due to the large strain caused by the flexural deformation of the tire 10 . Therefore, as the tire 10 is used for a long period of time, the unevenness of the surface of the two-dimensional code 40 changes, and as a result, the readability of the two-dimensional code 40 tends to deteriorate. Therefore, it is preferable that the two-dimensional cord 40 is positioned away from the radially outer end of the bead filler rubber 22 radially outwardly or inwardly in the tire radial direction. The distance between the outer end of the bead filler rubber 22 in the tire radial direction and the edge of the two-dimensional cord 40 closest to this end is 20% or more of the length of the two-dimensional cord 40 along the tire radial direction; is preferably 40% or more.

According to one embodiment, the two-dimensional cord range in the tire radial direction in which the two-dimensional cord 40 is provided passes through the center point M in the tire radial direction of the two-dimensional code range, and is normal to the surface of the sidewall portion 10S at the center point M. It is preferable that the thickness of the side rubber 20 defined on the normal line along the line direction is 2.5 mm or more. By setting the thickness of the side rubber 20 to 2.5 mm or more in the area of the two-dimensional code, cracks are less likely to occur in the hole bottoms of the dot holes 40a, and crack propagation can be suppressed. Decrease in readability can be suppressed.

According to one embodiment, the two-dimensional cord range in the tire radial direction in which the two-dimensional cord 40 is provided is a bonding line where two rubbers are bonded to each other (hereinafter also referred to as a rubber bonding line) on the surface of the sidewall portion 10S. It is preferable that the position is located radially outwardly or inwardly of the tire, or on both sides in the tire circumferential direction. By providing the two-dimensional code 40 at a location separated from the rubber joint line, it is possible to prevent local loss of rubber around the dot holes 40a of the two-dimensional code 40 during long-term use of the tire 10. . When the two-dimensional code 40 is provided at the rubber joint line, at least a portion of the dot hole 40a crosses the rubber joint surface inside the tire, and a part of the joint surface is exposed to the outside air. Therefore, with long-term use of the tire 10, the joint surface is exposed to ozone and ultraviolet rays, and oxidative deterioration becomes severe. Oxidative deterioration causes the rubber around the joint surface to harden, making it easy to chip off due to deformation and distortion. In particular, since the joint is a portion where rubbers are joined together, cracks are likely to occur along the joined surfaces. Due to this crack, the rubber around the dot holes 40a is likely to come off. The rubber bonding line on the surface of the side rubber wall portion 10S may extend along the tire radial direction (for example, one long side rubber 20 may be bonded to both ends on the tire circumference), or it may extend along the tire circumferential direction. (for example, different rubbers are joined along the tire circumferential direction). For this reason, the two-dimensional cords 40 are preferably provided on the surface of the sidewall portion 10S at positions spaced outward or inward in the tire radial direction from the rubber joint line, or on both sides in the tire circumferential direction. The distance between the rubber bonding line and the edge of the two-dimensional cord 40 closest to this rubber bonding line is 20 times the length of the two-dimensional cord 40 along the tire radial direction or the length along the tire circumferential direction. % or more, more preferably 40% or more.

According to one embodiment, when the cross-sectional height of the tire 10 along the tire radial direction is SH, from the innermost position of the bead core 16 of the tire 10 in the tire radial direction to the center of the two-dimensional cord 40 in the tire radial direction. A distance H along the tire radial direction to the point M is preferably 70% or less of the cross-sectional height SH. The cross-sectional height SH and the innermost position of the bead core 16 in the tire radial direction are determined by the tire profile cross-sectional shape when the tire 10 is mounted on a regular rim and the tire cavity is filled with air at a regular internal pressure. FIG. 4 is a diagram for explaining an example of the arrangement position of the two-dimensional code 40. As shown in FIG. FIG. 4 illustrates a preferable arrangement range R2 of the cross-sectional height SH, the distance H, and the central point M of the two-dimensional cord 40 in the tire radial direction.
If the two-dimensional code 40 is stamped so that the distance H is over 70% of the cross-sectional height SH, the deformation of the tire 10 caused by the applied load causes an extremely large strain on the rubber at the stamped position. Cracks are more likely to occur in the dot holes 40a, and the cracks are more likely to develop. The distance H is preferably 40% or less of the cross-sectional height SH. The two-dimensional code 40 is arranged so that the center point M is located inside the tire radial direction with respect to the tire maximum width position when the tire 10 is mounted on a regular rim and the tire cavity is filled with air at a regular internal pressure. , a two-dimensional code 40 is preferably provided.

Moreover, the two-dimensional cords 40 are preferably provided on each of the sidewall portions 10S on both sides of the tire 10 in the tire width direction. Even when the tire 10 is mounted on the vehicle, the two-dimensional code 40 stamped on one sidewall portion 10S can always be reliably read.

(Example, Comparative Example)
In order to confirm the effects of the above-described embodiment, a tire 10 (tire size: 195/65R15 91H) in which the two-dimensional code 40 (specifically, the QR code (registered trademark)) is arranged at different positions in the tire radial direction was tested. Various types were produced, and the readability test of the two-dimensional code 40 during long-term use of the tire 10 was conducted. The tire configuration of the tire 10 was the configuration shown in FIG.
The shape of the dot hole 40a of the two-dimensional code 40 was circular, the inner diameter of the circular shape was 0.5 mm, and the hole depth D was 0.7 mm. The size of the QR code (registered trademark) was 15 mm×15 mm.
For long-term use of the tire 10, a drum test was performed on the tire 10 on an indoor drum under predetermined conditions simulating long-term use. The content of the drum test is a low pressure test based on FMVSS139 (rim size 15×6J, XL: 160 kPa, load 100% LI). Specifically, the tire 10 was run for 10,000 km at a speed of 81 km/h while being irradiated with ozone at an ozone concentration of 100 pphm as the predetermined conditions simulating long-term use. After running, the possibility of reading the two-dimensional code 40 with the portable terminal was examined by changing the illumination light.

Ten tires 10 after running were prepared for each of the examples and the comparative examples, and the two-dimensional code 40 was read by variously changing the application of illumination light. The ratio of the number of correct readings to the number of readings of the two-dimensional code 40 was defined as the reading rate. The reading rate was based on Comparative Example 1 (the reading rate of Comparative Example 1 was set to 100), and the reading rates of Comparative Example 2 and Examples 1 to 5 were indexed. Indexed so that the higher the index, the better the reading rate.

Table 1 below shows the result (readability) of the reading rate of the two-dimensional code 40 with respect to the arrangement position of the two-dimensional code 40 .
In Table 1 below, the "position of the two-dimensional cord arrangement range" is the distance along the tire radial direction from the radially inner end of the run-flat reinforcing rubber 25 to the nearest edge of the two-dimensional cord 40, and the two-dimensional It represents the ratio (%) of the distance along the tire radial direction of the furthest edge of the cord 40 to the height H (see FIG. 3). In Comparative Example 1, the distance in the tire radial direction from the radially inner end of the run-flat reinforcing rubber 25 to the closest edge of the two-dimensional cord 40 was 8% of the height H, and the distance along the tire radial direction was 8% of the height H. It means that the distance along the tire radial direction of the farthest edge of the two-dimensional cord 40 from the tire radially inner end of 25 is 26% of the height H.
In Comparative Examples 1 and 2, the ratio of the two-dimensional cords 40 is less than 10% or more than 90%, and the two-dimensional cord range extends from the inner end of the run-flat reinforcing rubber 25 in the tire radial direction and the tire radial direction. It shows that the distance from the outer edge is not more than 10% of the height H of the run-flat reinforcing rubber 25 .
In Example 5, the thickness of the side rubber 20 was changed to adjust the distance L with respect to Example 2.

From the comparison between Comparative Examples 1 and 2 and Examples 1 to 4, the two-dimensional cord range is determined from the tire radially inner end and the tire radially outer end of the run-flat reinforcing rubber 25 to the tire diameter of the run-flat reinforcing rubber 25. In Examples 1 to 4, in which the height H along the direction is separated by 10% or more, the readability of the two-dimensional code 40 associated with long-term use of the tire 10 is improved compared to Comparative Examples 1 and 2. Recognize.
The readability of the two-dimensional codes 40 of Examples 2 and 3 in which T/Tmax is 20% or more is higher than that in Examples 1 and 4 in which T/Tmax is less than 20%. It can be seen that the readability of the
Further, from a comparison of Examples 2 and 5, Example 2 in which the ratio (T/L) is 0.6 or more has a longer life of the tire 10 than Example 5 in which the ratio (T/L) is less than 0.6. It can be seen that the readability of the two-dimensional code 40 is improved with use.

Although the pneumatic tire of the present invention has been described in detail above, the present invention is not limited to the above embodiments and examples, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

10 pneumatic tire 10T tread portion 10S sidewall portion 10B bead portion 12 carcass ply 14 belts 14a, 14b belt material 16 bead core 18 tread rubber 20 side rubber 22 bead filler rubber 23 bead filler reinforcing rubber 24 rim cushion rubber 25 run flat reinforcing rubber 26 Inner liner rubber 30 Belt cover 40 Two-dimensional code 40a Dot hole 42 Dot pattern area 42a Data cell area 42b Cutout symbol area 44 Blank area

Claims (11)

A pneumatic tire,
a pair of annular bead cores;
at least one toroidal carcass ply wound around the pair of bead cores and provided between the pair of bead cores;
a side rubber provided on each sidewall portion of the pneumatic tire so as to cover the carcass ply from the outside of the tire;
a run-flat reinforcing rubber that is provided on each sidewall portion of the pneumatic tire so as to cover the carcass ply from the inside of the tire and suppresses deformation of the side rubber when the pneumatic tire is run-flat;
On the surface of the sidewall portion, a two-dimensional code is provided in which a dot pattern is formed by two types of dark and light elements that are formed to be mutually identifiable by surface unevenness,
The two-dimensional code range in which the two -dimensional code is provided is the run-flat reinforcing rubber when the pneumatic tire is mounted on a regular rim and the pneumatic tire is filled with a regular internal pressure in the tire radial direction. From the tire radially inner end and the tire radially outer end of the run-flat reinforcing rubber along the tire radial direction when the pneumatic tire is mounted on a regular rim and filled with the regular internal pressure A pneumatic tire characterized by being located in a range separated by 10% or more of the height H. The run-flat reinforcing rubber defined on a normal line passing through the center point in the tire radial direction of the two-dimensional cord range in which the two-dimensional cord is provided and along the normal direction of the surface of the sidewall portion at the center point. The pneumatic tire according to claim 1, wherein the thickness T of the run-flat reinforcing rubber is 20% or more of the maximum thickness Tmax of the run-flat reinforcing rubber. The ratio (T/L) of the thickness T of the run-flat reinforcing rubber to the distance L from the center point defined on the normal line to the carcass ply is 0.6 or more. pneumatic tires. The pneumatic tire according to any one of claims 1 to 3, wherein the run-flat reinforcing rubber has a rubber hardness of 75 to 90 according to JIS K-6253. The pneumatic tire according to any one of claims 1 to 4, wherein the two-dimensional code is provided on a smooth surface without ridges. Claims 1 to 5, wherein the two-dimensional cord range is located radially outward or inward in the tire radial direction from the end of the folded portion of the carcass ply wound around the bead core. The pneumatic tire according to any one of . A bead filler rubber is sandwiched between a carcass ply before folding around the bead core of the carcass ply and a folded portion after the carcass ply is wound, and extends outward in the tire radial direction of the bead core,
The two-dimensional code range in which the two-dimensional code is provided is located at a position spaced radially outward or inward from the radially outer end of the bead filler rubber in the tire radial direction. The pneumatic tire according to any one of items 1 and 2. The two-dimensional code range in which the two-dimensional code is provided is defined on a normal line passing through the center point of the two-dimensional code range in the tire radial direction and along the normal direction of the surface of the sidewall portion at the center point. The pneumatic tire according to any one of claims 1 to 7, wherein the thickness of the side rubber that is formed is 2.5 mm or more. The two-dimensional cord range, in which the two-dimensional cord is provided, is spaced outward or inward in the tire radial direction, or on both sides in the tire circumferential direction from a joint line where two rubbers are joined to each other on the surface of the sidewall portion. A pneumatic tire according to any one of claims 1 to 8, in position. Along the tire radial direction from the innermost position of the bead core in the tire radial direction to the maximum outer diameter position of the tire when the pneumatic tire is mounted on a regular rim and the pneumatic tire is filled with a regular internal pressure When the cross-sectional height is SH, when the pneumatic tire is mounted on a regular rim and the pneumatic tire is filled with regular internal pressure, the innermost position of the bead core in the tire radial direction is two The pneumatic tire according to any one of claims 1 to 9, wherein the distance along the tire radial direction to the center point in the tire radial direction of the dimension code range is 70% or less of the cross-sectional height SH. . The pneumatic tire according to any one of claims 1 to 10, wherein the two-dimensional cords are provided on each of the sidewall portions on both sides of the pneumatic tire in the tire width direction.

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