JP7110633B2 - Pneumatic tire and method for manufacturing 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 a sidewall portion of the tire and a pneumatic tire manufacturing method.

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 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. In particular, it has been proposed to provide a two-dimensional code composed of a pattern of dark and light elements on the tire side surface by imprinting a predetermined pattern of dot holes on the tire side surface (side wall portion) (Patent document 1).

The two-dimensional code, which is formed by imprinting a predetermined pattern of dot holes on the tire side surface, does not disappear unless the tire side surface is worn, so that the tire can be managed effectively.

WO2005/000714

A pneumatic tire stamped with such a two-dimensional code and provided with a plurality of dot holes can read the two-dimensional code when it is new. In some cases, the reading of the two-dimensional code 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. For this reason, when the tire is used for a long period of time, cracks that occur near the dot holes of the two-dimensional code develop, causing local loss of the rubber around the dot holes, making it difficult to distinguish between dark and light elements. It is not preferable that the readability of the code is degraded. For this reason, it is preferable to suppress local loss of the rubber around the dot holes of the two-dimensional code during long-term use of the tire.

Therefore, the present invention provides a pneumatic tire that can improve reading of the two-dimensional code by suppressing the rubber from missing around the dot holes of the two-dimensional code stamped on the sidewall even after long-term use of the tire. It aims at providing the manufacturing method of a tire and a pneumatic tire.

One aspect of the present invention is a pneumatic tire including a pair of annular sidewall portions formed by winding a side rubber member elongated in one direction around the tire circumference.
Both ends of the side rubber member are provided with inclined end surfaces inclined in the same direction with respect to the thickness direction of the side rubber member.
The sidewall portion is
a joint portion in which the inclined end surfaces of the side rubber members are joined to each other;
a two-dimensional code in which a dot pattern is formed by two types of dark and light elements that are formed to be mutually identifiable by unevenness of the surface of the sidewall portion,
The two-dimensional code is provided at a location spaced from the joint portion in the tire circumferential direction.

The outer edge of the two-dimensional cord closest to the joint line of the joint portion on the surface of the sidewall portion in the tire circumferential direction is located on one side in the tire circumferential direction where the inclined end surface extends from the joint line. is preferably spaced apart by 35 mm or more in the tire circumferential direction.

In the portion where the two-dimensional cord is provided, the distance from the surface of the side rubber member to the inner surface of the side rubber member on the carcass ply side of the pneumatic tire closest to the portion is 2.5 mm or more. is preferably.

The portion where the two-dimensional cord is provided is provided away in the tire circumferential direction from a carcass ply material overlapping portion where the carcass ply material of the pneumatic tire overlaps in two layers at a part of the tire circumference. is preferred.

It is preferable that the distance from the carcass ply overlapping portion to the outer edge of the two-dimensional cord closest in the tire circumferential direction is at least a distance corresponding to the length of the two-dimensional cord along the tire circumferential direction.

One aspect of the present invention is a method for manufacturing a pneumatic tire, comprising:
A side rubber member that is long in one direction and has inclined end faces that are inclined in the same direction with respect to the thickness direction of the rubber member at both ends of the side rubber member. A step of forming a pair of annular sidewall portions by joining them together to produce an unvulcanized tire, and recording and holding position information in the tire circumferential direction of the joined portions where the inclined end surfaces are joined together;
A step of providing a two-dimensional code in which a dot pattern is formed by two types of dark and light elements formed so as to be mutually identifiable by surface unevenness on the sidewall portion of the vulcanized tire obtained by vulcanizing the unvulcanized tire; Prepare.
In the step of providing the two-dimensional code, the two-dimensional code is provided at a location spaced from the joint in the tire circumferential direction based on the position information of the joint in the tire circumferential direction.

In the step of providing the two-dimensional cord, the outer edge of the two-dimensional cord closest to the joint line on the surface of the sidewall portion of the joint portion in the tire circumferential direction extends from the joint line in the tire circumferential direction where the inclined end face extends. It is preferable that the two-dimensional cord is provided so as to be spaced apart from the joint line by 35 mm or more in the tire circumferential direction on one side of the tire.

According to the pneumatic tire and the method for manufacturing a pneumatic tire described above, even if the pneumatic tire is used for a long period of time, the two-dimensional code stamped on the sidewall portion is prevented from missing rubber around the dot holes. Dimensional code reading can be improved.

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. (a) is a diagram for explaining an example of a side rubber member along the tire circumferential direction, and (b) is a diagram for explaining a joint portion of the side rubber member and an arrangement position of a two-dimensional cord in the embodiment. FIG. 10 is a diagram illustrating an inconvenient example regarding the joint portion of the side rubber member and the arrangement position of the two-dimensional code; It is a figure explaining an example of the arrangement position of a carcass ply material overlap part and a two-dimensional code in an embodiment.

Hereinafter, the pneumatic tire of the embodiment will be described in detail.
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 the embodiments described below, a two-dimensional code is engraved on the sidewall portion. The marking referred to in the present embodiment refers to a mode in which laser light is converged on the surface of the sidewall portion to concentrate energy to locally heat and incinerate the side rubber member to form a plurality of minute dot holes on the surface. It also includes forming a two-dimensional code by imprinting unevenness on the member by another means.

A two-dimensional code 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 portion 10S is a portion provided so as to sandwich the tread portion 10T from both sides in the tire width direction, and the surface thereof is the surface of the sidewall portion. 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 members, and a tread rubber member 18, a side rubber member 20, and a bead filler rubber member 22 around these skeleton members. , a rim cushion rubber member 24 and an inner liner rubber member 26 .

The carcass ply 12 is wound around a pair of annular bead cores 16 and provided between the pair of bead cores 16 to form a toroidal shape. The carcass ply 12 is composed of a carcass ply material in which organic fibers are coated with rubber. 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 on the tire equator line CL outside the carcass ply 12 in the tire radial direction. The belt 14 is composed of a member in which steel cords are arranged at a predetermined angle, for example, 20 to 30 degrees, with respect to the tire circumferential direction and covered with rubber. The width in the tire width direction is longer. The inclination directions of the steel cords of the two layers of belt materials 14a and 14b are opposite to each other. 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 member 18 is provided outside the belt 14 in the tire radial direction, and side rubber members 20 are connected to both end portions of the tread rubber member 18 to form sidewall portions 10S. A rim cushion rubber member 24 is provided at the inner end in the tire radial direction of the side rubber member 20 and contacts the rim on which the tire 10 is mounted. A bead is provided outside the bead core 16 in the tire radial direction so as to be sandwiched between a portion of the carcass ply 12 before being wound around the bead core 16 and a portion of the carcass ply 12 after being wound around the bead core 16. A filler rubber member 22 is provided. An inner liner rubber member 26 is provided on the inner surface of the tire 10 facing the air-filled tire cavity area surrounded by the tire 10 and the rim. The side rubber member 20 is a member elongated in one direction, and is wound around the tire circumference to form a pair of annular sidewall portions 10S.
In addition, between the belt material 14b and the tread rubber member 18, a three-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 three, and may be one or two.
A two-dimensional code 40 (indicated by a thick line in FIG. 1) is provided on the surface of the sidewall portion 10S of the tire 10 (surface of the sidewall).

(two-dimensional code)
FIGS. 2A and 2B are diagrams for explaining an example of the two-dimensional code 40 of one embodiment.
The two-dimensional code 40 is stamped on the surface (sidewall) of the side rubber member 20 of the sidewall portion 10S, as shown in FIG. According to one embodiment, the two-dimensional cords 40 are formed on the surfaces of the side rubber members 20 of both sidewall portions 10S on both sides in the tire width direction. According to another embodiment, it is formed on the surface of the side rubber member 20 of one of the sidewall portions 10S.
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 converges laser light on the surface of the sidewall portion 10S to concentrate energy and locally heat and incinerate the side rubber member 20 to form minute dot holes 40a (see FIG. 2(b)) on the surface. It is a pattern formed by stamping multiple times. The dot hole 40a is, for example, a conical hole, and has a diameter on the tread surface of, for example, 0.1 to 1.0 mm, and a depth (b in FIG. 2(b)) of, for example, 0.3 to 1 mm. 0 mm.
As shown in FIG. 2(a), the two-dimensional code 40 is constructed by providing one dot hole 40a (concave portion) in the unit cell area of the dark area among the unit cells that divide the dark and light elements of the two-dimensional code 40. It is That is, in the two-dimensional code 40, one dot hole 40a forms one unit cell area (dark area) with a high density element corresponding to a plurality of rectangular unit cell areas of the same size divided into a lattice. It has a configuration in which the dot holes 40a are arranged so as to do. In FIG. 2(a), the dark area of the unit cell area is indicated by a black area.

The two-dimensional code 40 shown in FIG. 2(a) is a QR code (registered trademark) and includes a dot pattern area 42 in which a dot pattern is formed with two types of shading elements. A blank area 44 is provided around the dot pattern area 42 and is surrounded by light elements that are the same as the light elements among the light and dark elements. The blank area 44 is a quiet zone in the QR code (registered trademark), and is an area necessary for reading the QR code (registered trademark). The thickness of blank area 44 surrounding dot pattern area 42 is preferably, for example, 4 to 5 times the dimensional size of the unit cell area within dot pattern area 42 . For example, the thickness w of the blank area 44 is preferably 4% to 25% of the maximum dimension of the two dimensions of the rectangular shape of the dot pattern area 42 . Here, the outer edge of the two-dimensional code 40 is the outer edge of the dot pattern area 42 .
Since the two-dimensional code 40 shown in FIG. 2A 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.

Such a two-dimensional code 40 is provided on the sidewall portion 10S. The two-dimensional code 40 is provided at a location spaced apart in the tire circumferential direction from the joining portion of the side rubber member 20 of the sidewall portion 10S. The joint portion of the side rubber member 20 is a portion where the inclined end surfaces formed at both ends of the side rubber member 20 are joined to each other.

FIG. 3(a) is a diagram illustrating an example of a side surface of the side rubber member 20 along the tire circumferential direction. The side rubber member 20 is a rubber member elongated in one direction, and as shown in FIG. 3A, both ends of the side rubber member 20 in the tire circumferential direction direction). The reason why the inclined end surfaces 20a are provided at both ends is that when the both ends of the side rubber member 20 are connected by forming the annular sidewall portion 10S, the both end surfaces of the side rubber member 20 are butted against each other so that the both ends can be reliably connected to each other. This is for increasing the joint surface by inclining both end surfaces. An inclination angle θ (see FIG. 3A) of the inclined end surface 20a with respect to the thickness direction of the side rubber member 20 is, for example, 10 degrees or more and less than 90 degrees, preferably 10 degrees or more and 80 degrees or less.

The two-dimensional cord 40 is provided at a location spaced apart from the joint portion 50 of the side rubber member 20 in the tire circumferential direction. To prevent local loss of rubber around dot holes 40a of the two-dimensional code 40 during long-term use of the pneumatic tire 10 by providing the two-dimensional code 40 at a location spaced apart from the joining part 50.例文帳に追加can be done. FIG. 4 is a diagram illustrating an inconvenient example regarding the arrangement positions of the joint 50 and the two-dimensional code 40. As shown in FIG. As shown in FIG. 4 , when the two-dimensional cord 40 is provided at the joint portion 50 in the tire circumferential direction, the dot hole 40 a crosses the inclined end face 20 a of the side rubber member 20 . Therefore, part of the inclined end surface 20a is exposed to the outside air. Therefore, due to long-term use of the pneumatic tire 10, the inclined end surface 20a is exposed to ozone and ultraviolet rays, so that oxidation deterioration becomes severe. Oxidative deterioration causes rubber to harden, making it easier to chip due to deformation and distortion. In particular, since the joint portion 50 is a portion where the inclined end surfaces 20a are joined together, cracks are likely to occur along the joined inclined end surfaces 20a. As a result, as shown in FIG. 4, regions X and Y of the side rubber member around the dot holes 40a, which are located above the inclined end face 20a in the drawing, are likely to be missing.
When the joint 50 is not exposed to ozone or ultraviolet rays, no cracks or the like are formed or propagated, as is the case with the non-bonded portion 50 . Therefore, the two-dimensional cord 40 is provided at a location spaced apart from the joint portion 50 of the side rubber member 20 in the tire circumferential direction.

The position of the joint portion 50 or the inclined end surface 20a of the side rubber member 20 in the tire circumferential direction is obtained by peeling off the sidewall portion 10S from the pneumatic tire 10 and cutting it along the tire circumferential direction. can be identified by examining the At the joint portion 50 of the side rubber member 20, the color of the rubber changes on the cut surface, so the joint portion 50 can be identified.

According to one embodiment, the outer edge 41 of the two-dimensional cord 40 closest to the joint line 52 on the surface of the sidewall portion 10</b>S of the joint portion 50 in the tire circumferential direction extends from the joint line 52 to the inclined end surface 30 a in the tire circumferential direction. 35 mm or more from the joint line 52 in the tire circumferential direction. FIG. 3(b) is a diagram illustrating the layout positions of the joint portion 50 of the side rubber member 20 and the two-dimensional cord 40 in one embodiment.
It is preferable that the distance L1 shown in FIG. ₃ (b) is 35 mm or more. If the distance L1 is _less than 35 mm, part of the two-dimensional cord 40 overlaps part of the inclined end face 20a in the tire circumferential direction, and part of the rubber member of the two-dimensional cord 40 is likely to be lost. When the pneumatic tire 10 is a passenger car tire, the tire from the bonding line 52 on the surface side (outer side) of the side rubber member 20 to the bonding line 54 on the inner side is determined by the thickness of the side rubber member 20 and the inclination angle θ of the inclined end surface 20a. _The distance L2 along the circumferential direction is at most approximately 35 mm. For example, when the thickness of the side rubber member 20 is 6 mm and the inclination angle θ of the inclined end face 20a in the thickness direction of the side rubber member ₂₀ is 80 degrees, the distance L2 is approximately 34 mm. Therefore, when the pneumatic tire 10 is a tire for a passenger car, it is preferable that the distance L1 is 35 _mm or more. More preferably, the distance L1 is 40 _mm or more.
Further, even if the two-dimensional code 40 does not partially overlap the inclined end face 20a in the tire circumferential direction, even if a crack occurs at the bottom of the dot hole of the two-dimensional code 40, the crack will propagate to the inclined end face 20a. In order to prevent this, it is preferable that the distance L1 is 35 _mm or more.

According to one embodiment, in the portion where the two-dimensional cord 40 is provided, the side rubber member located on the side of the carcass ply material 12 of the pneumatic tire 10 closest to the portion where the two-dimensional cord 40 is provided from the surface of the side rubber member 20 The distance to the inner surface of 20 is preferably 2.5 mm or more. That is, it is preferable that the thickness of the side rubber member 20 in the two-dimensional cord 40 is 2.5 mm or more. As a result, even if the pneumatic tire 10 is used for a long period of time, cracks are less likely to occur from the hole bottoms of the dot holes 40a. difficult to do. That is, in terms of durability of the pneumatic tire 10, the thickness of the side rubber member 20 in the two-dimensional cord 40 is preferably 2.5 mm or more. The thickness of the side rubber members 20 in the two-dimensional code 40 is more preferably 3.0 mm or more, and more preferably 5.0 mm or less.

According to one embodiment, the portion where the two-dimensional cord 40 is provided is, as shown in FIG. It is preferable to be provided away from 60 in the tire circumferential direction. FIG. 5 is a diagram illustrating an example of arrangement positions of the carcass ply material overlapping portion 60 and the two-dimensional code 40 in the embodiment.
In the carcass ply material overlapping portion 60, the carcass ply material is locally formed into two layers, and the elongation amount due to pulling is smaller than that of the other single layer portion. Therefore, when the tire cavity region of the pneumatic tire 10 is filled with air to a predetermined internal pressure, the sidewall portion 10S expands due to the internal pressure. Since the amount of elongation is small, the surface of the sidewall portion 10S after being filled with air has a locally concave shape along the tire circumferential direction. At this time, the surface of the sidewall portion 10S on both sides of the carcass ply material overlapping portion 60 is formed with an inclined surface whose surface height continuously decreases or increases. If the two-dimensional code 40 is provided on this inclined surface, the direction of the reflected light of the illumination light changes due to the unevenness of the surface of the inclined surface, and the two-dimensional code 40 may not be reliably read. Further, when air is filled, the inclined surface is distorted due to the difference in expansion amount between the carcass ply material overlapping portion 60 and the other portions. Due to this distortion, the size of the dot holes 40a of the two-dimensional code 40 also changes depending on the location, and it may be difficult to read the dot pattern by the shading element. In addition, the slanted surface is distorted due to air filling. Rubber fatigue becomes significant around the dot holes 40a, and cracks are likely to occur and develop. From this point of view, the arrangement position of the two-dimensional cord 40 is preferably separated from the carcass ply material overlapping portion 60 as shown in FIG. The distance from the carcass ply material overlapping portion 60 to the outer edge of the two-dimensional cord 40 closest in the tire circumferential direction is preferably equal to or greater than the length of the two-dimensional cord 40 along the tire circumferential direction.

As described above, in order to provide the two-dimensional code 40 at a position spaced apart from the location of the joint 50 in the tire circumferential direction, it is important to retain information on the location of the joint 50 in the tire circumferential direction in advance. . Such a pneumatic tire 10 can be manufactured by the following manufacturing method.

(1) A side rubber member elongated in one direction, and both ends of the side rubber member are provided with inclined end faces 20a inclined in the same direction with respect to the thickness direction of the rubber member. An unvulcanized tire is manufactured by winding the side rubber member 20 around the tire circumference and mating the inclined end faces 20a of the side rubber member 20 to form a pair of annular sidewall portions 10S. At this time, position information in the tire circumferential direction of the joining portion 50 of the inclined end surfaces 20a that are joined together is recorded and held. An unvulcanized tire is formed into a ring shape by winding the side rubber member 20, the carcass ply material, the rubber member 18, the bead filler rubber member 22, and other tire constituent members on the tire forming drum. At this time, a mark is put on the corresponding position on the unvulcanized tire corresponding to the reference position on the circumference of the tire building drum. A controller of a molding apparatus (not shown) obtains positional information of the joint 50, such as how far (for example, how many angles) the joint 50 is away from the position of the mark on the tire circumference. retain memory.
(2) A stamping device (not shown) stamps a two-dimensional code 40 on the sidewall portion of the vulcanized tire obtained by vulcanizing the unvulcanized tire thus produced in a tire mold. A two-dimensional code 40 is stamped on the vulcanized tire without being filled with air. At this time, the marking device calls up the position information of the joint 50 stored by the control device, and marks the two-dimensional code 40 at a location spaced apart from the joint 50 in the tire circumferential direction based on this position information. Specifically, since the mark attached to the unvulcanized tire remains on the vulcanized tire, the position of the joint 50 is specified from the position information of the joint 50 with reference to the position of this mark. be able to.
As described above, the positional information of the joint 50 when molding the unvulcanized tire is recorded and held by the control device, so that the two-dimensional code 40 is placed at a position spaced apart from the joint 50 in the tire circumferential direction. can be set to

When the two-dimensional cord 40 is provided, the outer edge of the two-dimensional cord 40 closest to the joint line 52 on the surface of the sidewall portion 10S of the joint portion 50 in the tire circumferential direction extends from the joint line 52 in the tire circumferential direction. It is preferable to provide the two-dimensional cord 40 so as to be separated from the joining line 52 by 35 mm or more in the tire circumferential direction. As a result, even if the pneumatic tire 10 is used for a long period of time, it is possible to prevent the two-dimensional code 40 stamped on the sidewall portion 10S from missing rubber around the dot holes 40a.

(Example, Comparative Example)
In order to confirm the effect of the above-described embodiment, the pneumatic tire 10 (tire size: 195 /65R15 91H) were prepared, and the readability test of the two-dimensional code 40 in long-term use was conducted. The tire structure of the pneumatic tire 10 was the structure shown in FIG. The inclination angle θ of the inclined end surface 20a with respect to the thickness direction of the side rubber member 20 was set to 80 degrees, and the average thickness of the side rubber member 20 was set to 6 mm.
The inner diameter of the dot hole 40a of the two-dimensional code 40 was set to 0.5 mm, and the depth was set to 0.7 mm. The size of the QR code (registered trademark) was 15 mm×15 mm.

For long-term use of the pneumatic tire 10, the pneumatic tire 10 was rolled on an indoor drum under predetermined conditions simulating long-term use (rim size 15×6J, internal pressure 120 kPa, load 615 kg). Specifically, the pneumatic tire 10 was run for 10,000 km at a speed of 81 km/h while irradiating the pneumatic tire 10 with ozone at an ozone concentration of 100 pphm. After running, the possibility of reading the two-dimensional code 40 with the portable terminal was examined by changing the illumination light.

Five pneumatic tires 10 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 of Comparative Example 1 was used as a reference (the reading rate of Comparative Example was set to 100), and the reading rate of Examples was indexed. Indexed so that the higher the index, the better the reading rate.
Table 1 below shows the result of the reading rate of the two-dimensional code 40 with respect to the arrangement position of the two-dimensional code 40 in the tire circumferential direction.
In Table 1, “presence or absence of overlap between the two-dimensional code and the joint portion” means whether or not the two-dimensional code 40 is separated from the joint portion 50 . When the “overlap” is “present”, it means that the two-dimensional code 40 is at the joint 50 . means that there is

In the comparative example shown in Table 1, many cracks occurred around the dot holes 40a and the rubber was missing, and the reading rate of the two-dimensional code 40 after long-term use of the pneumatic tire 10 was greatly reduced compared to when it was new. On the other hand, in Examples 1 to 5, the loss of rubber around the dot holes 40a was reduced as compared with the comparative example, and the decrease in the reading rate from the new product was suppressed. Thus, by providing the two-dimensional cord 40 at a location spaced apart from the location of the joint portion 50, even if the pneumatic tire 10 is used for a long period of time, the rubber around the dot holes 40a of the two-dimensional cord 40 can be suppressed from missing. It was found that the deterioration of reading in long-term use can be suppressed.
In addition, from the comparison of Examples 1 to 3, it was found that the distance L1 of 35 mm or more in the tire circumferential direction is preferable from the viewpoint of suppressing deterioration in reading during long-term use. That is, it can be seen that it is preferable that the outer edge 41 of the two-dimensional cord 40 be positioned away from the joining line 54 inside the side rubber member 12 shown in FIG. 3(b).
In addition, from the comparison of Examples 2, 4, and 5, it is preferable that the thickness of the side rubber member 12 is 2.5 mm or more in terms of suppressing deterioration in reading during long-term use of the pneumatic tire 10. I found out.

Although the pneumatic tire and the method for manufacturing a pneumatic tire according to the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and examples, and various improvements and improvements can be made without departing from the gist of the present invention. Of course, it may be changed.

10 pneumatic tire 10T tread portion 10S sidewall portion 10B bead portion 11 carcass cord 12 carcass ply 13 coating rubber 12a, 12b ply 12ae, 12be, 12e carcass ply end 14 belt 14a, 14b belt material 16 bead core 18 tread rubber member 20 side rubber Member 20a Inclined end surface 22 Bead filler rubber member 24 Rim cushion rubber member 26 Inner liner rubber member 30 Belt cover 40 Two-dimensional code 40a Dot hole 41 Outer edge 42 Dot pattern area 42a Data cell area 42b Cutout symbol area 44 Blank area 50 Joining portion 52 , 54 Joining line 60 Carcass ply material overlapping portion

Claims (7)

A pneumatic tire comprising a pair of annular sidewall portions formed by winding a side rubber member long in one direction around the tire circumference,
Both ends of the side rubber member are provided with inclined end surfaces inclined in the same direction with respect to the thickness direction of the side rubber member,
The sidewall portion is
a joint portion in which the inclined end surfaces of the side rubber members are joined to each other;
a two-dimensional code in which a dot pattern is formed by two types of dark and light elements that are formed to be mutually identifiable by unevenness of the surface of the sidewall portion,
A pneumatic tire, wherein the two-dimensional cord is provided at a location spaced from the joint portion in the tire circumferential direction. The outer edge of the two-dimensional cord closest to the joint line of the joint portion on the surface of the sidewall portion in the tire circumferential direction is located on one side in the tire circumferential direction where the inclined end surface extends from the joint line. 2. The pneumatic tire according to claim 1, which is spaced apart in the tire circumferential direction by 35 mm or more. In the portion where the two-dimensional cord is provided, the distance from the surface of the side rubber member to the inner surface of the side rubber member on the carcass ply side of the pneumatic tire closest to the portion is 2.5 mm or more. The pneumatic tire according to claim 1 or 2, wherein The portion where the two-dimensional cord is provided is provided away in the tire circumferential direction from a carcass ply material overlapping portion in which the carcass ply material of the pneumatic tire overlaps in two layers at a part of the tire circumference. The pneumatic tire according to any one of items 1 to 3. 5. The method according to claim 4, wherein the distance from the carcass ply overlapping portion to the outer edge of the two-dimensional cord closest in the tire circumferential direction is at least a distance corresponding to the length of the two-dimensional cord along the tire circumferential direction. Pneumatic tires as described. A method for manufacturing a pneumatic tire, comprising:
A side rubber member that is long in one direction and has inclined end faces that are inclined in the same direction with respect to the thickness direction of the rubber member at both ends of the side rubber member. A step of forming a pair of annular sidewall portions by joining them together to produce an unvulcanized tire, and recording and holding position information in the tire circumferential direction of the joined portions where the inclined end surfaces are joined together;
A step of providing a two-dimensional code in which a dot pattern is formed by two types of dark and light elements formed so as to be mutually identifiable by surface unevenness on the sidewall portion of the vulcanized tire obtained by vulcanizing the unvulcanized tire; prepared,
In the step of providing the two-dimensional code, the two-dimensional code is provided at a location spaced apart from the joint in the tire circumferential direction based on positional information of the joint in the tire circumferential direction. manufacturing method. In the step of providing the two-dimensional cord, the outer edge of the two-dimensional cord closest to the joint line on the surface of the sidewall portion of the joint portion in the tire circumferential direction extends from the joint line in the tire circumferential direction where the inclined end face extends. 7. The method of manufacturing a pneumatic tire according to claim 6, wherein the two-dimensional cord is provided so as to be spaced apart from the joining line by 35 mm or more in the tire circumferential direction on one side of the tire.

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