Pneumatic tire

Abstract

To provide a pneumatic tire with high durability even though having a mark display part.SOLUTION: A tire 1 comprises color rubbers 61 each, provided on a portion of a side wall 20, which each protrude from a profile line PL of the side wall 20 outward in a tire axial direction in a cross-sectional view of a tire meridian cross section, with a protruding end face thereof formed with a mark display part 60 having a mark surface 70. The tire has regions in each of which the color rubber 61, a side wall rubber 21 and a rim strip rubber 14 are arranged in this order from an outer side in the tire axial direction, and overlapped with one another in the tire axial direction when viewed from the tire axial direction. Therein modulus of the side wall rubber 21 is larger than modulus of the color rubber 61, and modulus of the rim strip rubber 14 is larger than modulus of the side wall rubber 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to pneumatic tires.

Background Art

[0002] Conventionally, for the purpose of improving the appearance of a tire, etc., a pneumatic tire has been known in which a protruding portion corresponding to a logo is formed on a sidewall, and for example, white rubber (hereinafter referred to as colored rubber) is exposed on its surface to provide a logo display portion (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although sidewall rubber, rim strip rubber, etc. are provided around the colored rubber, separation is feared to occur at the interface where these rubbers with different rigidities (moduli) come into contact. In Patent Document 1 described above, it is stated that the durability against separation, etc. is improved by providing irregularities on these interfaces.

[0005] However, as described in the patent document, the effect of improving durability by providing the above-mentioned irregularities is slight, and further improvement in durability is desired.

[0006] An object of the present disclosure is to provide a pneumatic tire having a logo display portion and high durability.

Means for Solving the Problems

[0007] The pneumatic tire of the present disclosure is a pneumatic tire including a pair of beads, a pair of sidewalls extending radially outward of the tire from each of the pair of beads, and a tread disposed between the pair of sidewalls, the pneumatic tire including sidewall rubber forming the sidewalls, rim strip rubber forming an outer surface of the bead, and colored rubber provided on a part of the sidewall and forming a logo display portion having a logo surface protruding axially outward of the tire from a profile line of the sidewall in a cross-sectional view of a tire meridian plane, and in a state viewed from the tire axial direction, the colored rubber, the sidewall rubber, and the rim strip rubber are arranged in this order from the outside in the tire axial direction and have an overlapping region in the tire axial direction, the modulus of the sidewall rubber is larger than the modulus of the colored rubber, and the modulus of the rim strip rubber is larger than the modulus of the sidewall rubber.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a pneumatic tire having a logo display portion and having high durability.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment for carrying out the present disclosure will be described with reference to the drawings and the like.

[0011] Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows a half cross-section in the tire axial direction (tire meridian plane) of a pneumatic tire 1 according to an embodiment. FIG. 2 is a partial enlarged cross-sectional view in which the vicinity of the logo display portion 60 in FIG. 1 is enlarged. FIG. 3 is a side view of the tire 1 according to the embodiment. Note that, in FIG. 3, in order to clarify the range of the colored rubber 61, shapes unnecessary for the description are omitted.

[0012] The tire 1 is, for example, a tire for a passenger car. The cross-sectional view in FIG. 1 is a cross-sectional view in the tire axial direction (tire meridian cross-section) of the tire 1 mounted on a regular rim (not shown) and filled with a regular internal pressure in a non-loaded state. The regular rim is the rim defined for each tire in a standard system including the standard on which the tire is based. For example, it is the standard rim in JATMA, and it is the "Measuring Rim" in TRA and ETRTO. The regular internal pressure is the air pressure defined for each tire in a standard system including the standard on which the tire is based. In the case of tires for trucks and buses and light trucks, in JATMA, it is the maximum air pressure, in TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO, it is the "INFLATION PRESSURE". In the case of a passenger car tire, it is usually 180 kPa, but in the case of a tire marked with Extra Load or Reinforced, it is 220 kPa.

[0013] The basic structure of the tire 1 is symmetric about the cross-section in the tire axial direction (tire meridian plane). FIG. 1 shows the cross-section of the right half of the tire 1, and the left half (not shown) has the same structure. In FIG. 1, the symbol S1 is the tire equatorial plane. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and is located at the center in the tire axial direction.

[0014] Here, the tire axial direction is a direction parallel to the tire rotation axis and is the left - right direction of the paper surface in FIG. 1. In FIG. 1, it is illustrated as the tire axial direction X. The inner side in the tire axial direction is a direction approaching the tire equatorial plane S1 and is the left side of the paper surface in FIG. 1. The outer side in the tire axial direction is a direction away from the tire equatorial plane S1 and is the right side of the paper surface in FIG. 1.

[0015] Also, the tire radial direction is a direction perpendicular to the tire rotation axis and is the up - down direction of the paper surface in FIG. 1. In FIG. 1, it is illustrated as the tire radial direction Y. The outer side in the tire radial direction is a direction away from the tire rotation axis and is the upper side of the paper surface in FIG. 1. The inner side in the tire radial direction is a direction approaching the tire rotation axis and is the lower side of the paper surface in FIG. 1. Further, the tire circumferential direction is an arc line centered on the tire rotation axis and is a direction along the rotation direction of the tire 1, and is shown in the arc line Z direction in FIG. 3.

[0016] As shown in FIG. 1, the tire 1 according to the embodiment includes a pair of beads 10, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 disposed between the pair of sidewalls 20, a carcass ply 40 bridged and disposed between the pair of beads 10, and an inner liner 50 disposed on the tire inner cavity side of the carcass ply 40.

[0017] The pair of beads 10 are disposed at both ends in the tire axial direction and on the inner side in the tire radial direction. The bead 10 has a bead core 11, a bead filler 12 extending radially outward from the bead core 11, a chafer 13, and a rim strip rubber 14.

[0018] The bead core 11 is an annular member in which a metal bead wire coated with rubber is wound a plurality of times in the tire circumferential direction. The bead core 11 is a member that serves to fix the air - filled tire 1 to the rim.

[0019] The bead filler 12 has a tapered shape with a decreasing thickness as it extends from the inner side in the tire radial direction to the outer side in the tire radial direction. The bead filler 12 is provided to increase the rigidity of the peripheral portion of the bead 10 and ensure high maneuverability and stability. The bead filler 12 is composed of, for example, rubber having a higher hardness than the surrounding rubber members. The inner surface of the bead filler 12 in the tire radial direction is joined to the outer surface of the bead core 11 in the tire radial direction.

[0020] The chafer 13 further surrounds the outside of the carcass ply 40 that surrounds the bead core 11 and the bead filler 12.

[0021] The rim strip rubber 14 is disposed on the outer side of the chafer 13 and the carcass ply 40 in the tire axial direction. The rim strip rubber 14 is a member that contacts the rim on which the tire 1 is mounted.

[0022] The sidewall 20 includes a sidewall rubber 21 disposed on the outer side of the carcass ply 40 in the tire axial direction, a side block 22, and a logo display portion 60. The sidewall rubber 21, the side block 22, and the logo display portion 60 constitute the outer wall surface of the tire 1.

[0023] The sidewall rubber 21 surrounds the logo display portion 60 and is disposed on the outer side and the inner side in the tire radial direction of the logo display portion 60 in FIG. 1. In the following description, the sidewall rubber 21 provided on the outer side in the tire radial direction of the logo display portion 60 is referred to as the outer sidewall rubber 21A, and the sidewall rubber 21 provided on the inner side in the tire radial direction of the logo display portion 60 is referred to as the inner sidewall rubber 21B as necessary. The outer sidewall rubber 21A and the inner sidewall rubber 21B in the present embodiment are formed of the same material. A rim line 21a is formed on the inner sidewall rubber 21B.

[0024] The side block 22 is a portion formed in a block shape at the radially outer end of the sidewall 20 in the tire diameter direction, and protrudes outward in the tire axial direction from the profile line PL of the sidewall 20. The side block 22 of the embodiment extends from the radially outer end of the sidewall 20 in the tire diameter direction to the axially outer end of the tread 30 in the tire axial direction, and this portion is made of a rubber different from the sidewall rubber 21.

[0025] The sidewall 20 is the portion that bends the most when the tire 1 acts as a cushion. Therefore, usually, the sidewall rubber 21 of the sidewall 20 is made of a flexible rubber having fatigue resistance. Details of the logo display portion 60 will be described later.

[0026] The tread 30 has an endless belt 31 and a cap ply 32, and a tread rubber 33.

[0027] The belt 31 is disposed outside the carcass ply 40 in the tire diameter direction. The cap ply 32 is disposed outside the belt 31 in the tire diameter direction.

[0028] The belt 31 is a member that reinforces the tread 30. The belt 31 of the embodiment has a two-layer structure including an outer belt 311 and an inner belt 312 in the tire diameter direction. Both the outer belt 311 and the inner belt 312 have a structure in which a plurality of cords such as steel cords are covered with rubber. Note that the belt 31 is not limited to a two-layer structure, and may have a single-layer or three-layer or more structure.

[0029] The cap ply 32 is a member that reinforces the tread 30 together with the belt 31. The cap ply 32 has a structure in which a plurality of insulating organic fiber cords such as polyamide fibers are covered with rubber. By providing the cap ply 32, it is possible to improve durability and reduce road noise during driving.

[0030] The tread rubber 33 is disposed on the tire radial outside of the cap ply 32. The tread rubber 33 is a member that constitutes the tread surface 34 which is the outer surface of the tread 30.

[0031] The carcass ply 40 constitutes a ply that forms the framework of the tire 1. The carcass ply 40 is embedded in the tire 1 in a manner that passes between a pair of beads 10 through a pair of sidewalls 20 and the tread 30. The carcass ply 40 includes a plurality of carcass cords (not shown) that form the framework of the tire 1. The plurality of carcass cords extend, for example, in the tire axial direction and are arranged side by side in the tire circumferential direction. The carcass cords are composed of insulating organic fiber cords such as polyester and polyamide. The plurality of carcass cords are covered with rubber to form the carcass ply 40.

[0032] The carcass ply 40 has a ply main body portion 40A that extends from one bead core 11 to the other bead core 11 and extends between the tread 30 and the bead 10, a pair of bent portions 40B that are folded back at the bead core 11 from the ply main body portion 40A, and a pair of folded-back portions 40C that extend radially outward of the tire from each of the bent portions 40B. The ply main body portion 40A, the bent portions 40B, and the folded-back portions 40C surround the bead filler 12 and the bead core 11. The folded-back portion 40C of the portion radially outside the tire than the bead filler 12 is overlapped with the ply main body portion 40A.

[0033] The carcass ply 40 of the embodiment has a two-layer structure including a first carcass ply 41 on the tire radial outside and a second carcass ply 42 on the tire radial inside in the portion of the tread 30. The carcass ply 40 is not limited to such a two-layer structure and may have a single-layer or a three-layer or more structure.

[0034] The chafer 13 of the bead 10 described above is provided so as to surround the inner end portion in the tire radial direction of the carcass ply 40 including the bent portion 40B. Further, the rim strip rubber 14 is disposed on the outer side in the tire axial direction of the chafer 13 and the folded-back portion 40C of the carcass ply 40. The outer side in the tire radial direction of the rim strip rubber 14 is covered with the inner sidewall rubber 21B.

[0035] The inner liner 50 is a member that constitutes the inner surface of the tire 1, and covers the inner surface of the ply main body portion 40A of the carcass ply 40 and the inner surface of the chafer 13 of the pair of beads 10. The inner liner 50 is made of air-permeability-resistant rubber and prevents the air in the tire inner cavity from leaking to the outside. The inner liner 50 of the tire 1 of the embodiment has a single-layer structure, but may be composed of a plurality of layers such as a two-layer structure of an outer inner liner and an inner inner liner.

[0036] As shown in FIGS. 1 and 2, the logo display portion 60 protrudes outward in the tire axial direction from the profile line PL of the sidewall 20. The logo display portion 60 has a flat logo surface 70 on its protruding end face. The logo display portion 60 has a colored rubber 61 and a cover rubber 65. The colored rubber 61 is disposed on the outer side in the tire axial direction of the carcass ply 40 and is a different-colored rubber having a color different from that of the sidewall rubber 21 and the cover rubber 65.

[0037] The color of the cover rubber 65 is preferably black, which is the same color as the tire 1. As the color of the colored rubber 61, white, which provides a clear contrast with black, is preferred, but it is not limited thereto, and for example, yellow, green, red, etc. may also be selected.

[0038] As shown in FIG. 2, the portion that is substantially visually recognized as the logo 60A in the logo display portion 60, that is, the portion that is visually recognized as characters if the logo is characters, is composed of the exposed portion 62 of the colored rubber 61 that protrudes from the surface of the sidewall 20 and is exposed on the side surface of the sidewall 20, and the border 66 formed by the cover rubber 65 arranged so as to surround the colored rubber 61. The surfaces of the exposed portion 62 of the colored rubber 61 and the border 66 of the cover rubber 65 form the same flat surface. That is, the logo 60A (for example, characters) is composed of a flat single surface.

[0039] As shown in FIG. 2, the cover rubber 65 is a relatively thin rubber film, is arranged on the outer surface side of the tire of the colored rubber 61, and covers the portion other than the exposed portion 62 of the colored rubber 61.

[0040] The logo display portion 60 is formed so as to protrude outward in the tire axial direction from the profile line PL of the sidewall 20 in a part of the tire circumferential direction of the sidewall 20 when the tire 1 is vulcanized and molded. After the tire 1 is vulcanized and molded, the entire colored rubber 61 is covered with the cover rubber 65, and the exposed portion 62 is not formed. After the vulcanization and molding of the tire 1, the cover rubber 65 corresponding to the logo 60A is ground and removed by means such as buffing, so that the colored rubber 61 is exposed, and the logo 60A composed of the exposed portion 62 of the colored rubber 61 and the border 66 of the cover rubber 65 is exposed. The ground surface of the logo display portion 60 constitutes the logo surface 70 which is the flat single surface of the logo 60A.

[0041] As shown in FIG. 3, the colored rubber 61 of the present embodiment is arranged annularly along the circumferential direction in a part of the sidewall 20. Also, as shown in FIGS. 2 and 3, the colored rubber 61 of the present embodiment has a main body region 61A, an inner connection region 61C provided on the inner side in the tire radial direction of the main body region 61A, and an outer connection region 61B provided on the outer side in the tire radial direction of the main body region 61A.

[0042] The main body region 61A is an annular region including the emblem 60A and the exposed portion 62, and in this embodiment, it is disposed in direct contact with a topping rubber (not shown) covering the carcass ply 40. Therefore, in a cross-sectional view of the tire meridian plane, in the main body region 61A, the inner surface of the color rubber 61 in the tire axial direction is a curved surface along the profile line (the curved surface shape on the outer side in the tire axial direction) of the carcass ply 40. Note that a configuration may be adopted in which the sidewall rubber 21 is disposed between the topping rubber of the carcass ply 40 and the main body region 61A.

[0043] The outer connection region 61B is located on the outer side in the tire diameter direction of the main body region 61A and is disposed on the outer side in the tire axial direction of the outer sidewall rubber 21A, and is an annular region where the color rubber 61 and the outer sidewall rubber 21A are connected. Further, in the outer connection region 61B, the thickness of the color rubber 61 in the tire axial direction gradually decreases as it goes toward the inner side in the tire diameter direction. More specifically, in the vicinity of the outer end portion in the tire diameter direction of the color rubber 61 in a state viewed from the tire axial direction, in the outer connection region 61B where the color rubber 61 and the outer sidewall rubber 21A overlap in the tire axial direction, in a cross-sectional view of the tire meridian plane, the thickness of the color rubber 61 becomes thinner as it goes toward the outer side in the tire diameter direction, and the thickness of the outer sidewall rubber 21A becomes thicker. With this configuration, a wide outer connection region 61B where the color rubber 61 and the outer sidewall rubber 21A are connected is ensured, and peeling between the color rubber 61 and the outer sidewall rubber 21A is suppressed. Further, since the color rubber 61 is disposed on the outer side in the tire axial direction of the outer sidewall rubber 21A, it is possible to suppress the outer sidewall rubber 21A from wrapping around to the outer side in the tire axial direction of the color rubber 61 during the molding of the tire 1, and the occurrence of appearance defects can be prevented.

[0044] The inner connection region 61C is located on the inner side in the tire diameter direction of the main body region 61A and is arranged on the outer side in the tire axial direction than the inner sidewall rubber 21B, and is an annular region where the inner side in the tire diameter direction of the colored rubber 61 and the inner sidewall rubber 21B are connected. Also, in the inner connection region 61C, the thickness of the colored rubber 61 in the tire axial direction gradually decreases toward the inner side in the tire diameter direction. More specifically, in the vicinity of the inner end portion in the tire diameter direction of the colored rubber 61 in a state viewed from the tire axial direction, in the inner connection region 61C where the colored rubber 61 and the inner sidewall rubber 21B overlap in the tire axial direction, in a cross-sectional view in the tire meridian plane, the thickness of the colored rubber 61 becomes thinner toward the inner side in the tire diameter direction, and the thickness of the inner sidewall rubber 21B becomes thicker. With this configuration, a wide inner connection region 61C where the colored rubber 61 and the inner sidewall rubber 21B are connected is ensured, and peeling between the colored rubber 61 and the inner sidewall rubber 21B is suppressed. Also, since the colored rubber 61 is arranged on the outer side in the tire axial direction than the inner sidewall rubber 21B, it is possible to suppress the inner sidewall rubber 21B from wrapping around to the outer side in the tire axial direction than the colored rubber 61 during the molding of the tire 1, and it is possible to prevent the occurrence of appearance defects.

[0045] FIG. 4 is a partial enlarged cross-sectional view at the same position as FIG. 2 for explaining the dimensional relationship of each component near the logo display portion 60 of FIG. 1. In FIG. 4, components unnecessary for explanation are omitted for easy understanding, and only a partial shape of the bead filler 12 is shown. In the cross-sectional view of the tire meridian plane shown in FIG. 4, the length of the curved surface along the profile line (the curved surface shape on the outer side in the tire axial direction) of the carcass ply 40 of the surface facing the carcass ply 40 of the colored rubber 61 is defined as LC. Also, the length of the curved surface along the profile line (the curved surface shape on the outer side in the tire axial direction) of the surface facing the carcass ply 40 of the inner sidewall rubber 21B disposed radially inward of the colored rubber 61 in the tire diameter direction is defined as LS. Further, the length of the curved surface along the profile line (the curved surface shape on the outer side in the tire axial direction) of the surface facing the carcass ply 40 of the rim strip rubber 14 is defined as LR. The relationship among the length LC, the length LS, and the length LR desirably satisfies the following relationship in order to suppress the peeling between the colored rubber 61 and the inner sidewall rubber 21B.

[0046] 0.12LC ≦ LS ≦ 0.25LC 0.70LC ≦ LR ≦ 1.50LC

[0047] If it is less than the lower limit value of LS, it does not function as a buffer material. Also, if it exceeds the upper limit of LS, a sufficient grounding area of the colored rubber cannot be ensured to secure the appearance. Further, if it is less than the lower limit value of LR, a sufficient rubber area in contact with the rim cannot be ensured. Furthermore, if it exceeds the upper limit value of LR, since the rubber is hard, the distortion to other rubbers becomes large and the durability decreases. Therefore, the relationship among the length LC, the length LS, and the length LR desirably satisfies the above relationship.

[0048] Here, the curved surface along the profile line (the curved surface shape on the outer side in the tire axial direction) of the carcass ply 40 refers to the curved surfaces of the colored rubber 61, the inner sidewall rubber 21B, and the rim strip rubber 14 that face the curved surface shape on the outer side in the tire axial direction of the carcass ply 40, and it is not necessarily required to be arranged in direct contact with the carcass ply 40. For example, the rim strip rubber 14 of the present embodiment has a region facing the carcass ply 40 with the chafer 13 sandwiched therebetween on the inner end side in the tire diameter direction. Even in such a case, the length as the "curved surface along the profile line of the carcass ply 40" shown in FIG. 4 is set to each of the above lengths (length LC, length LS, and length LR). That is, each of these lengths (length LC, length LS, and length LR) is the actual length (sometimes referred to as the perimeter length) along the carcass ply 40 of the projection surface when the surfaces of the colored rubber 61, the inner sidewall rubber 21B, and the rim strip rubber 14 facing the carcass ply 40 are projected onto the carcass ply 40 in the facing direction.

[0049] Also, in the cross-sectional view of the tire meridian plane shown in FIG. 4, the length along the profile line of the carcass ply 40 of the opposing surface of the colored rubber 61 disposed to face the bead filler 12 along the profile line of the carcass ply 40 is defined as LCP. This length LCP is the length of the range of the length LC that faces the bead filler 12, in other words, the overlap amount of the opposing surface of the colored rubber 61. Also, the length LCP is also the length by which the position of the radially outer end of the bead filler 12 is separated from the inner connection region 61C. Since the modulus of the bead filler 12 is larger than that of other rubber materials constituting the tire 1, at the radially outer end of the bead filler 12, the hardness difference between the bead filler 12 and the surrounding material is large, so the strain difference tends to be large. The inner connection region 61C, that is, the interface between the colored rubber 61 and the inner sidewall rubber 21B also has a large strain difference. If the radially outer end of the bead filler 12 with a large strain difference and the interface between the colored rubber 61 and the inner sidewall rubber 21B with a large strain difference are arranged close to each other, peeling is likely to occur particularly at the interface between the colored rubber 61 and the inner sidewall rubber 21B. Therefore, the value of the length LCP described above is important. This is because the longer the length LCP, the farther the radially outer end of the bead filler 12 and the interface between the colored rubber 61 and the inner sidewall rubber 21B are separated in the tire radial direction.

[0050] Therefore, three types of tires, tires A, B, and C, with different lengths LCP were manufactured and a deformation test was conducted, and an experiment was carried out to observe and evaluate the state of the interface between the colored rubber 61 and the inner sidewall rubber 21B. The results are shown in the following table.

[0051]

Table 1

[0052] Although no peeling occurred on any of the interfaces, for Tire A where deformation regarded as signs of peeling was confirmed, it was evaluated as △. Also, for Tire B and Tire C, since neither peeling nor signs of peeling were observed, they were evaluated as 〇. From these experimental results, it is desirable that the length LCP be 10 mm or more in order to suppress the deformation of the colored rubber 61 and suppress the peeling between the colored rubber 61 and the inner sidewall rubber 21B.

[0053] Further, in the cross-sectional view of the tire meridian plane shown in FIG. 4, when the maximum length along the profile line PL of the sidewall 20 in the range where the colored rubber 61 protrudes outward in the tire axial direction from the profile line PL of the sidewall 20 is defined as LD, in order to suppress the peeling between the colored rubber 61 and the inner sidewall rubber 21B, it is desirable to satisfy the following relationship.

[0054] LC / LD≧1.1

[0055] Also, in the overlapping region 61D on the inner side in the tire radial direction within the inner connection region 61C of the embodiment, in the state viewed from the tire axial direction, the colored rubber 61, the inner sidewall rubber 21B, the rim strip rubber 14, and the bead filler 12 are arranged in this order from the outside in the tire axial direction, and it is a region that overlaps in the tire axial direction. By providing this overlapping region 61D, it is possible to obtain the effect of suppressing the concentration of strain energy applied to the interface between the colored rubber 61 and the inner sidewall rubber 21B, and it is possible to suppress the peeling between the colored rubber 61 and the inner sidewall rubber 21B.

[0056] Further, in the overlapping region 61D, although a plurality of configurations as described above overlap in the tire axial direction, since the moduli of each configuration are different from each other, the behavior during deformation of the tire 1, that is, the strain also differs for each configuration. If materials with significantly different moduli are adjacent to each other in the overlapping region 61D, the difference in strain during deformation of the tire 1 at the interface will be significantly different, and there is a risk of peeling occurring at the interface. Therefore, in the tire 1 of the embodiment, the values of the moduli of the materials overlapping in the tire axial direction in the overlapping region 61D gradually change, that is, the moduli of the materials overlapping in the tire axial direction gradually increase from the outside in the tire axial direction toward the inside in the tire axial direction, and the ratio is as shown in the following table. Note that the bead filler 12 could not have its modulus measured at 300% deformation.

[0057]

Table 2

[0058] In other words, regarding the moduli of the materials of each part, the following relationships exist. Let the modulus at 300% displacement of the colored rubber 61 be MC, the modulus at 300% displacement of the inner sidewall rubber 21B be MS, and the modulus at 300% displacement of the rim strip rubber 14 be MR. Then, the relationships 1.5MC ≤ MS ≤ 3.0MC and 4.0MC ≤ MR ≤ 5.5MC are satisfied.

[0059] Also, let the modulus at 100% displacement of the sidewall rubber be MS100 and the modulus at 100% displacement of the bead filler be MB100. Then, the relationship 3.5MS100 ≤ MB100 ≤ 6.0MS100 is satisfied.

[0060] In this way, since the moduli of the materials overlapping in the tire axial direction gradually increase from the outside in the tire axial direction toward the inside in the tire axial direction, it is possible to suppress a significant difference in the strain during deformation of the tire 1 at the interface between different materials, and it is possible to suppress peeling at the interface where the materials around the colored rubber 61 come into contact with each other.

[0061] Also, in the tire 1 of the present embodiment, in a state viewed from the tire axial direction, the carcass ply 40 has a region where at least four layers are provided in a range overlapping with the colored rubber. In particular, in a state viewed from the tire axial direction, the carcass ply 40 in a range overlapping with the inner connection region 61C has a four-layer structure. Thereby, deformation of the colored rubber 61 and the inner sidewall rubber 21B in the inner connection region 61C is suppressed, and peeling between the colored rubber 61 and the inner sidewall rubber 21B can be suppressed.

[0062] According to the tire 1 according to the above-described present embodiment, the following effects are obtained.

[0063] (1) The tire 1 according to the present embodiment is a pneumatic tire including a pair of beads 10, a pair of sidewalls 20 extending radially outward in the tire diameter direction from each of the pair of beads 10, and a tread 30 disposed between the pair of sidewalls 20. The tire includes sidewall rubber 21 (21A, 21B) forming the sidewall 20, rim strip rubber 14 forming the outer surface of the bead 10, and colored rubber 61 provided on a part of the sidewall 20 and forming a logo display portion 60 having a logo surface 70 protruding radially outward in the tire axial direction from a profile line PL of the sidewall 20 in a cross-sectional view in the tire meridian plane. In a state viewed from the tire axial direction, from the outside in the tire axial direction, the colored rubber 61, the sidewall rubber (21B), and the rim strip rubber 14 are arranged in this order and have a region overlapping in the tire axial direction. The modulus of the sidewall rubber (21B) is larger than the modulus of the colored rubber 61, and the modulus of the rim strip rubber 14 is larger than the modulus of the sidewall rubber (21B).

[0064] As a result, the modulus values are arranged in ascending order from a material with a small modulus value to a material with a large modulus value from the outside to the inside in the tire axial direction. Therefore, the modulus does not change abruptly at the interface where different materials are in contact, and the change in strain at the interface can be reduced. Thus, peeling at the interface around the colored rubber 61 can be suppressed, and a pneumatic tire with high durability can be provided even if it has the emblem display portion 60.

[0065] (2) In the pneumatic tire according to (1), the bead 10 has a bead core 11 and a bead filler 12 extending radially outward of the tire from the bead core 11. In a state viewed from the tire axial direction, from the outside in the tire axial direction, the colored rubber 61, the sidewall rubber (21B), the rim strip rubber 14, and the bead filler 12 are arranged in this order and have an overlapping region in the tire axial direction. The modulus of the sidewall rubber (21B) is greater than the modulus of the colored rubber 61, the modulus of the rim strip rubber 14 is greater than the modulus of the sidewall rubber (21B), and the modulus of the bead filler 12 is greater than the modulus of the rim strip rubber 14. Pneumatic tire.

[0066] As a result, while ensuring high strength by the bead filler 12, the difference in strain at the material interface can be reduced, and peeling at the interface between the materials can be suppressed.

[0067] (3) In the pneumatic tire according to (1), when the modulus at 300% displacement of the colored rubber 61 is MC, the modulus at 300% displacement of the sidewall rubber 21 (21A, 21B) is MS, and the modulus at 300% displacement of the rim strip rubber 14 is MR, a pneumatic tire satisfying the relationship of 1.5MC ≦ MS ≦ 3.0MC and 4.0MC ≦ MR ≦ 5.5MC.

[0068] As a result, the moduli will be arranged in increasing order for the colored rubber 61, the sidewall rubber 21 (21A, 21B), and the rim strip rubber 14. Therefore, the difference in strain at the interface between the colored rubber 61 and the sidewall rubber 21 (21A, 21B), and at the interface between the sidewall rubber (21B) and the rim strip rubber 14 becomes smaller. Thus, peeling at the interface between the colored rubber 61 and the sidewall rubber 21 (21A, 21B), and at the interface between the inner sidewall rubber 21B and the rim strip rubber 14 can be suppressed.

[0069] (4) In the pneumatic tire according to (3), the bead 10 has a bead core 11 and a bead filler 12 extending radially outward of the tire diameter from the bead core 11. When the modulus at 100% displacement of the sidewall rubber 21 (21A, 21B) is defined as MS100 and the modulus at 100% displacement of the bead filler 12 is defined as MB100, the pneumatic tire satisfies the relationship of 3.5MS100 ≦ MB100 ≦ 6.0MS100.

[0070] As a result, the moduli will be arranged in increasing order for the colored rubber 61, the sidewall rubber 21 (21A, 21B), the rim strip rubber 14, and the bead filler 12. By dispersing the energy concentration of shear strain at the interface between the colored rubber 61 and the sidewall rubber 21 (21A, 21B), and at the interface between the inner sidewall rubber 21B and the rim strip rubber 14, the effect of suppressing peeling at that interface can be further enhanced.

[0071] (5) In the pneumatic tire according to any one of (1) to (4), the bead 10 has a bead core 11 and a bead filler 12 extending radially outward of the tire diameter from the bead core 11, and includes a carcass ply 40 provided from the tread 30 to the bead 10. In a cross-sectional view of the tire meridian plane, the length along the profile line PL of the carcass ply 40 of the opposing surface of the colored rubber 61 disposed to face the bead filler 12 along the profile line of the carcass ply 40 is 10 mm or more. Pneumatic tire.

[0072] Thereby, the end portion of the bead filler 12 on the radially outer side of the tire diameter and the interface between the colored rubber 61 and the inner sidewall rubber 21B can be separated in the tire diameter direction, and the deformation of the colored rubber 61 can be suppressed to suppress the peeling between the colored rubber 61 and the inner sidewall rubber 21B.

[0073] (6) In the pneumatic tire according to any one of (1) to (4), a carcass ply 40 provided from the tread 30 to the bead 10 is provided. In a cross-sectional view of the tire meridian plane, the length LC along the profile line of the carcass ply 40 of the surface of the colored rubber 61 facing the carcass ply 40 is defined. When the maximum length along the profile line PL of the sidewall 20 in the range where the colored rubber 61 protrudes axially outward of the tire from the profile line of the sidewall 20 is LD, a pneumatic tire satisfying the relationship of LC / LD≧1.1.

[0074] Thereby, when the tire 1 is molded, it is possible to prevent the sidewall rubber 21 (21A, 21B) from turning outward in the tire axial direction more than the colored rubber 61, and more stable production can be performed.

[0075] (Deformed form) Without being limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present disclosure.

[0076] (1) In the embodiment, "TOYO TIRES" is shown as an example of the logo display part. However, as the logo display part, in addition to such characters, figures, symbols, patterns, etc. can be mentioned, and it is not limited.

[0077] (2) In the embodiment, the tire 1 can be applied to pneumatic tires for passenger cars including light automobiles, SUVs, etc., and pneumatic tires for various vehicles such as light trucks, trucks, buses, etc.

[0078] In addition, each embodiment and modified form can be used in appropriate combination, but detailed description is omitted. Also, the present disclosure is not limited by each of the embodiments described above.

Explanation of Signs

[0079] 1 Tire 10 Bead 11 Bead Core 12 Bead Filler 13 Chafer 14 Rim Strip Rubber 20 Sidewall 21 Sidewall Rubber 21A Outer Sidewall Rubber 21B Inner Sidewall Rubber 21a Rim Line 22 Side Block 30 Tread 31 Belt 311 Outer Belt 312 Inner Belt 32 Cap Ply 33 Tread Rubber 34 Tread Surface 40 Carcass Ply 40A Ply Main Body Part 40B Bending Part 40C Folded-back Part 41 First Carcass Ply 42 Second Carcass Ply 50 Inner Liner 60 Logo Display Part 60A mark 61 colored rubber 61A body area 61B outer connection area 61C inner connection area 61D overlapping area 62 exposed part 65 cover rubber 66 border 70 mark surface

Claims

1. A pair of beads, A pair of sidewalls extending radially outward from each of the pair of beads in the tire radial direction, A tread disposed between the pair of sidewalls, An inflated tire comprising: Sidewall rubber forming the sidewall, Rim strip rubber forming the outer surface of the bead, Color rubber provided on a part of the sidewall, protruding radially outward in the tire axial direction from the profile line of the sidewall in a cross-sectional view of the tire meridian plane, and forming a logo display portion having a logo surface on the protruding end face, Comprising In a state viewed from the tire axial direction, the color rubber, the sidewall rubber, and the rim strip rubber are arranged in this order from the outside in the tire axial direction, and have a region overlapping in the tire axial direction, An inflated tire in which the modulus of the sidewall rubber is greater than the modulus of the color rubber, and the modulus of the rim strip rubber is greater than the modulus of the sidewall rubber.

2. In the inflated tire according to claim 1, The bead has a bead core and a bead filler extending radially outward from the bead core in the tire radial direction, In a state viewed from the tire axial direction, the color rubber, the sidewall rubber, the rim strip rubber, and the bead filler are arranged in this order from the outside in the tire axial direction, and have a region overlapping in the tire axial direction, An inflated tire in which the modulus of the sidewall rubber is greater than the modulus of the color rubber, the modulus of the rim strip rubber is greater than the modulus of the sidewall rubber, and the modulus of the bead filler is greater than the modulus of the rim strip rubber.

3. In the inflated tire according to claim 1, Let the modulus at 300% displacement of the color rubber be MC, Let the modulus at 300% displacement of the sidewall rubber be MS, Let the modulus at 300% displacement of the rim strip rubber be MR, then 1.5MC ≤ MS ≤ 3.0MC 4.0MC ≤ MR ≤ 5.5MC An inflated tire satisfying the relationship.

4. In the inflated tire according to claim 3, The bead has a bead core and a bead filler extending radially outward from the bead core in the tire radial direction, Let the modulus of the sidewall rubber at 100% displacement be MS100, and if the modulus of the bead filler at 100% displacement is MB100, then an inflated tire satisfying the relationship of 3.5MS100 ≤ MB100 ≤ 6.0MS100.

5. In the inflated tire according to Claim 1 or Claim 2, the bead has a bead core and a bead filler extending radially outward in the tire diameter direction from the bead core, and includes a carcass ply provided from the tread to the bead, in a cross-sectional view of the tire meridian plane, the length along the profile line of the carcass ply of the opposing surface of the colored rubber disposed to face the bead filler along the profile line of the carcass ply is 10 mm or more. An inflated tire.

6. In the inflated tire according to Claim 1 or Claim 2, it includes a carcass ply provided from the tread to the bead, in a cross-sectional view of the tire meridian plane, let the length along the profile line of the carcass ply of the surface of the colored rubber facing the carcass ply be LC, and if the maximum length along the profile line of the sidewall in the range where the colored rubber protrudes axially outward from the profile line of the sidewall is LD, then an inflated tire satisfying the relationship of LC / LD ≥ 1.

1. ​

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