pneumatic tires

Abstract

This invention provides a pneumatic tire that suppresses damage to the toe during rim assembly and suppresses severe rim misalignment during driving. The pneumatic tire has: a tread portion; a pair of sidewall portions (3); a pair of bead portions (4), in which bead cores (5) are embedded; an annular carcass (6) disposed between the pair of bead portions; and sidewall rubber (3G) disposed on the axially outer side of the carcass in each of the sidewall portions (3). Each pair of bead portions (4) has a bead bottom surface (40) that contacts the bead seat surface (Rs) of the rim (R). The bead bottom surface (40) includes: an inner region (41) axially containing the toe (Bt); and an outer region (42) axially containing the heel (Bh). The inner region (41) is formed by a canvas bead wrap (45). The outer region (42) is formed by sidewall rubber (3G) extending from the sidewall portion (3) inward toward the radial direction of the tire.

Description

Technical Field

[0001] This invention relates to pneumatic tires. Background Technology

[0002] When pneumatic tires are used under high load and high severity conditions, such as in racing, they may sometimes slip relative to the rim (rim offset).

[0003] In the past, in order to suppress such rim misalignment, a solution was proposed to place a rubber bead wrap with a specific fit and edge rubber on the bottom surface of the tire bead (for example, see Patent Document 1 below).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2015-199465

[0005] However, when a pneumatic tire is mounted on a rim, the tire toe, located at the inner end of the tire's axial direction and serving as the bottom surface of the bead, experiences friction against the rim and is subjected to significant forces. This tendency is particularly pronounced in racing pneumatic tires, which have enhanced lateral rigidity. Furthermore, in pneumatic tires where the bottom surface of the bead is made of materials such as edge rubber, gaps can easily form in the tire toe during rim assembly, leading to a compromise in air tightness. Summary of the Invention

[0006] The present invention was made in view of the above-mentioned problems, and its main objective is to provide a pneumatic tire that can suppress damage to the tire toe during rim assembly and suppress severe rim misalignment during driving.

[0007] This invention relates to a pneumatic tire, comprising: a tread portion; a pair of sidewall portions; a pair of bead portions, each containing a bead core; an annular carcass disposed between the pair of bead portions; and sidewall rubber disposed on the outer side of the carcass in the tire axial direction of each of the sidewall portions of the pair of sidewall portions. The pair of bead portions each have a bead bottom surface that contacts a bead seat surface of a rim. The bead bottom surface includes: an inner region in the tire axial direction, comprising a toe; and an outer region in the tire axial direction, comprising a heel. The inner region is formed by a canvas bead wrap, and the outer region is formed by the sidewall rubber extending inward from the sidewall portions in the tire radial direction.

[0008] In other embodiments of the present invention, the axial length of the tire in the inner region may be 2 mm or more.

[0009] In other embodiments of the present invention, when the length of the tire axial direction from the toe to the center of the bead core is set as Lc, and the width of the bead core in the tire axial direction is set as Wb, the length of the tire axial direction of the inner region is Lc+0.5Wb or less.

[0010] In other embodiments of the invention, the canvas bead wrapping may include: a first portion extending axially along the tire in the inner region; and a second portion extending outward from the bead toe in the radial direction of the tire.

[0011] In other embodiments of the invention, the canvas bead wrapping may include a third portion that overlaps the outer region of the sidewall rubber in the tire radial direction.

[0012] In other embodiments of the invention, the canvas bead wrapping may include a fourth portion connected to the third portion and extending outward in the radial direction of the tire.

[0013] In other embodiments of the present invention, the complex elastic modulus of the sidewall rubber may be 2 MPa to 10 MPa.

[0014] In other embodiments of the invention, the thickness of the sidewall rubber in the outer region may be 0.5 mm to 2.0 mm.

[0015] In other embodiments of the invention, each of the pair of bead portions may be provided with a side rubber having a greater complex elastic modulus than that of the sidewall rubber, the side rubber comprising a first side rubber disposed between the sidewall rubber and the tire body.

[0016] In other embodiments of the invention, each of the pair of bead portions may be provided with an edge rubber having a greater complex elastic modulus than that of the sidewall rubber, the edge rubber including a second edge rubber that overlaps the outer side of the canvas bead wrapping in the tire radial direction in the inner region.

[0017] In other embodiments of the present invention, the ratio (E*s / E*c) of the complex elastic modulus E*s of the sidewall rubber to the complex elastic modulus E*c of the edge rubber may be 0.10 to 0.20 or less.

[0018] In other embodiments of the invention, the compression ratio may be 10% to 16% on the inner portion of the bead core in the tire radial direction.

[0019] The pneumatic tire of the present invention, by adopting the above-described structure, can suppress damage to the tire toe during rim assembly and can suppress severe rim misalignment during driving. Attached Figure Description

[0020] Figure 1 This is a right half cross-sectional view of an inflatable tire according to one embodiment of the present invention.

[0021] Figure 2 yes Figure 1 Enlarged view of the main part of the tire bead area.

[0022] Label Explanation

[0023] 1: Tire; 2: Tire tread; 3: Tire sidewall; 3G: Tire sidewall rubber; 4: Bead; 4G: Sidewall rubber; 4G1: First sidewall rubber; 4G2: Second sidewall rubber; 5: Bead core; 40: Bead bottom; 41: Inner area; 42: Outer area; 45: Canvas bead wrap; 45a: Part 1; 45b: Part 2; 45c: Part 3; 45d: Part 4; Bt: Toe; Bh: Heel; R: Rim; Rs: Bead seat. Detailed Implementation

[0024] Hereinafter, one aspect of the present invention will be described with reference to the accompanying drawings.

[0025] Figure 1 A cross-sectional view of the pneumatic tire (hereinafter, sometimes simply referred to as "tire") 1 according to this embodiment is shown. Figure 1 In the middle, tire 1 is in a normal state.

[0026] [definition]

[0027] In this specification, the "normal condition" of tire 1 refers to the unloaded state in which tire 1 is assembled on a normal rim R, the internal pressure is adjusted to the normal internal pressure, and no load is applied to tire 1. In this specification, unless otherwise specified, the dimensions of tire 1 refer to values ​​measured under this normal condition.

[0028] In this specification, "standard rim" refers to a rim whose specifications are determined for each tire within a specification system that includes the specifications on which tire 1 is based. For example, if it is JATMA, it is "standard rim"; if it is TRA, it is "Design Rim"; and if it is ETRTO, it is "Measuring Rim".

[0029] In this manual, "regular internal pressure" refers to the air pressure determined for each tire in the specification system, including the specification on which tire 1 is based. For example, if it is JATMA, it is "maximum air pressure"; if it is TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and if it is ETRTO, it is "INFLATION PRESSURE".

[0030] like Figure 1As shown, the tire 1 has a tread portion 2, a pair of sidewall portions 3, a pair of bead portions 4 each embedded with a bead core 5, and a non-porous inner liner rubber layer 10 disposed on the inner surface of the tire cavity. Additionally, in Figure 1 The image shows only the right half of tire 1, but its left half has the same construction as the right half.

[0031] The tire 1 in this embodiment refers, for example, to a racing tire used under high load and high demand conditions. Racing tires are pneumatic tires designed for use on circular tracks. Sometimes, racing tires do not have a specified specification. In such cases, the rim and internal pressure that best utilize the tire's performance are determined to be the standard rim and standard internal pressure, respectively. Recommendations from tire manufacturers, racing regulations, etc., can be considered in this situation.

[0032] In other embodiments of the invention, the tire 1 may also be implemented as a passenger car tire or a pneumatic tire for a light truck.

[0033] In addition, the tire 1 has an annular carcass 6 disposed between a pair of bead portions 4, 4 and a belt layer 7 disposed on the outer side of the carcass 6 in the radial direction of the tire.

[0034] In this embodiment, the carcass 6 includes, for example, one or more carcass ply 6A consisting of multiple carcass cords covered with adhesive rubber. The carcass cords are arranged at an angle of 80 to 90 degrees relative to the tire equator C. Organic fiber cords are preferably used as carcass cords.

[0035] The carcass ply 6A includes, for example, a main body 6a extending between a pair of bead cores 5; and a pair of folded-back portions 6b, which fold back from the inner side to the outer side of the tire axial direction around the pair of bead cores 5. Preferably, in each bead portion 4, a bead triangle 8 made of hard rubber is disposed between the main body 6a and the folded-back portions 6b, extending in a conical shape from the bead core 5 outward in the tire radial direction.

[0036] The belt layer 7 is composed of multiple (two layers in this embodiment) belt ply layers 7A and 7B. Each belt ply layer 7A and 7B contains steel cords arranged at an angle of, for example, 15 to 40 degrees relative to the tire equator C. Such a belt layer 7 tightens the tire carcass 6, improving the rigidity of the tread 2.

[0037] In the tire 1 of this embodiment, a crown belt layer 9 is further disposed outside the belt layer 7 in the tire radial direction. The crown belt layer 9 comprises one or more crown belt plies. Each crown belt ply has crown belt cords arranged at an angle of 5° or less relative to the tire circumference. Organic fiber cords are preferably used as crown belt cords, for example.

[0038] The crown belt ply of this embodiment has a so-called seamless structure in which the crown belt cords are wound into a spiral shape along the tire circumference. Furthermore, the crown belt ply 9 of this embodiment includes: a full crown belt ply 9A that covers approximately the entire width of the belt ply 7; and an edge crown belt ply 9B that covers only the outer end of the belt ply 7 in the tire axial direction. As described above, the crown belt ply 9 suppresses bulging of the tread portion 2 during high-speed driving, improving handling stability and durability at high speeds.

[0039] In this embodiment, tread rubber 2G is disposed on the outer side of the crown belt layer 9 in the tire radial direction in the tread 2. The tread rubber 2G is disposed at least in the portion that contacts the road surface.

[0040] In each of the pair of sidewall portions 3, a sidewall rubber 3G is disposed on the outer side of the tire carcass 6 along the tire axial direction. The sidewall rubber 3G is formed of a relatively soft rubber material in order to maintain the flexibility of the sidewall portion 3 during driving.

[0041] The sidewall rubber 3G extends along the tire carcass 6 in the radial direction of the tire. The outer end of the sidewall rubber 3G in the radial direction of the tire connects to the tread rubber 2G. The inner end of the sidewall rubber 3G in the radial direction of the tire extends towards the bead portion 4. This will be described later.

[0042] Figure 2 Show Figure 1 A magnified view of a portion of the bead portion 4.

[0043] like Figure 2 As shown, each pair of bead portions 4 has a bead base surface 40. The bead base surface 40 is the portion that contacts the bead seat surface Rs of the standard rim (hereinafter, sometimes simply referred to as "rim") R. In this specification, as... Figure 2 As shown, the bead seat surface Rs of the rim R refers to the portion that supports the bead portion 4 from the inside in the tire radius direction, located on the inner side of the rim width direction, at a position greater than the rim diameter Dr.

[0044] The bottom surface of the bead 40 includes: an inner region 41 in the tire axial direction, which includes the toe Bt; and an outer region 42 in the tire axial direction, which includes the heel Bh.

[0045] In this manual, the toe (Bt) refers to the innermost end of the bead base 40 closest to the tire axial direction. For convenience, the heel (Bh) refers to the position of the bead base 40 corresponding to the rim diameter (Dr).

[0046] Regarding the tire 1 of this embodiment, the inner region 41 of the bead bottom surface 40 is formed by a canvas bead wrapping 45. Furthermore, the outer region 42 is formed by a sidewall rubber 3G extending inward from the sidewall portion 3 in the radial direction of the tire. Moreover, an interface F connecting the canvas bead wrapping 45 and the sidewall rubber 3G is formed in the bead bottom surface 40.

[0047] The canvas bead wrap 45 is a fabric-rubber composite obtained by covering the fabric with rubber, and has superior resistance to external damage compared to so-called rubber bead wraps made of rubber monomers. In this embodiment, the inner region 41 of the bead bottom surface 40 is formed by the canvas bead wrap 45, thereby suppressing damage to the toe (Bt) during rim assembly, etc. Therefore, the tire 1 of this embodiment can suppress the reduction in air tightness caused by damage to the toe (Bt).

[0048] On the other hand, due to the small deformation of the canvas bead wrap 45 and the exposure of part of the fabric, there is a tendency for the contact area between the canvas bead wrap 45 and the bead seat surface Rs of the rim R to be reduced compared to the rubber bead wrap. This is not preferable from the viewpoint of preventing rim misalignment. Therefore, in the tire 1 of this embodiment, a soft sidewall rubber 3G is disposed in the outer region 42 of the bead bottom surface 40. In this manner, in the outer region 42 of the bead bottom surface 40, the sidewall rubber 3G adheres tightly to the bead seat surface Rs of the rim R through its own compression deformation, thereby increasing the contact area with the bead seat surface Rs. Since the coefficient of friction of rubber is pressure-dependent, the sidewall rubber 3G, as described above, can generate a higher frictional force between the bead bottom surface 40 and the bead seat surface Rs by increasing its contact area and homogenizing the pressure distribution.

[0049] As described above, the tire 1 of this embodiment has a bead bottom surface 40 with a canvas bead wrapping 45 that has excellent resistance to external damage in its inner region 41 and a sidewall rubber 3G that generates high friction between itself and the bead seat surface Rs in its outer region 42. This can suppress damage to the tire toe Bt during rim assembly and suppress severe rim misalignment during driving.

[0050] Furthermore, in the tire 1 of this embodiment, by extending the sidewall rubber 3G to the outer region 42, it is not necessary to use new rubber components to solve the aforementioned problems. Therefore, the tire 1 of this embodiment can be manufactured, for example, without increasing the number of manufacturing processes or components.

[0051] In order to more effectively exert the aforementioned effects of suppressing damage to the tire toe Bt during rim assembly and suppressing severe rim misalignment during driving, the tire axial length Li of the inner region 41 is preferably 2 mm or more, and more preferably 3 mm or more.

[0052] On the other hand, when the tire axial length Li of the inner region 41 increases, the tire axial length Lo of the outer region 42 in the bead bottom surface 40 decreases, which may reduce the severe rim offset suppression effect during driving. From this point of view, for example, when the tire axial length from the toe Bt to the center 5c of the bead core 5 is set as Lc, and the tire axial width of the bead core 5 is set as Wb, the tire axial length Li of the inner region 41 is preferably Lc+0.5Wb or less, more preferably less than Lc+0.5Wb.

[0053] In a preferred embodiment, at least a portion of the sidewall rubber 3G is preferably located in the region inside the tire radius direction of the bead core 5 (the region inside the width Wb of the bead core 5) where the contact pressure with the bead seat surface Rs of the rim R is increased. That is, the interface F is preferably located in the region inside the tire radius direction of the bead core 5.

[0054] In a particularly preferred embodiment, as in this embodiment, the sidewall rubber 3G is preferably positioned inside the center 5c of the bead core 5 in the tire radial direction, where the contact pressure with the bead seat surface Rs of the rim R is highest. This further improves the rim misalignment suppression effect.

[0055] [Implementation Method of Canvas Bead Covering]

[0056] The canvas bead wrap 45 of this embodiment includes, for example, a first portion 45a that extends axially along the tire in the inner region 41; and a second portion 45b that extends outward from the tire toe Bt in the radial direction of the tire. Such a canvas bead wrap 45 can reinforce the tire toe Bt in both the axial and radial directions of the tire, and can further reliably suppress damage to the tire toe Bt during rim assembly.

[0057] The canvas bead wrap 45 of this embodiment may further include a third portion 45c, which overlaps the outer sidewall rubber in the tire radial direction in the outer region 42. The third portion 45c is continuous with the first portion 45a. The third portion 45c of the canvas bead wrap 45 effectively transmits the clamping force exerted by the bead core 5 to the sidewall rubber 3G located inside it in the tire radial direction, thereby helping to further improve the frictional force of the outer region 42 relative to the bead seat surface Rs.

[0058] The canvas bead wrapping 45 of this embodiment may further include a fourth portion 45d, which is connected to the third portion 45c and extends outward in the tire radial direction. In this embodiment, the fourth portion 45d extends in the tire radial direction between the sidewall rubber 3G and the tire carcass 6. This fourth portion 45d not only helps to improve the bending stiffness of the bead portion 4, but also allows the sidewall rubber 3G to fit tightly against the rim flange, thereby further suppressing rim misalignment.

[0059] [Sideboard rubber]

[0060] The complex elastic modulus of the sidewall rubber 3G is preferably 10 MPa or less, more preferably 8 MPa or less, and even more preferably 6 MPa or less. When mounted on the rim, this sidewall rubber 3G at the bottom surface 40 of the bead can be sufficiently compressed and deformed on the bead seat surface Rs, thereby generating high friction between it and the bead seat surface Rs, and more effectively suppressing rim misalignment.

[0061] On the other hand, when the complex elastic modulus of the sidewall rubber 3G is too small, the deformation of the outer region 42 increases during tire operation, which may worsen handling stability. From this perspective, the complex elastic modulus of the sidewall rubber 3G is preferably 2 MPa or more, more preferably 3 MPa or more, and even more preferably 4 MPa or more.

[0062] In this specification, regarding the complex elastic modulus of rubber, a rubber sample measuring 20 mm in length, 4 mm in width, and 1 mm in thickness was collected from the target area for viscoelasticity measurement. The measurement was conducted using an EPLEXOR (manufactured by GABO) at a temperature of 100°C, initial strain of 5%, dynamic strain of 1%, frequency of 10 Hz, and in elongation mode. In the case of 3G sidewall rubber, the sample was collected with the long side of the rubber sample aligned with the tire circumference.

[0063] In the outer region 42 of the bead base 40, the thickness of the sidewall rubber 3G is preferably in the range of 0.5 mm to 2.0 mm. By making the thickness of the sidewall rubber 3G 0.5 mm or more, a sufficient compression deformation area of ​​the sidewall rubber 3G can be obtained in the radial direction of the tire, and a higher frictional force can be generated between it and the bead seat surface Rs. In addition, by making the thickness of the sidewall rubber 3G 2.0 mm or less, excessive rubber deformation in the outer region 42 can be suppressed, preventing deterioration of handling stability. In addition, the thickness of the sidewall rubber 3G mentioned above is the thickness in the direction perpendicular to the bead base 40.

[0064] [Rubber Edge]

[0065] In a preferred embodiment, a side rubber 4G with a greater complex elastic modulus than the sidewall rubber 3G may also be provided in each of the pair of bead portions 4.

[0066] In this embodiment, the edge rubber 4G may include a first edge rubber 4G1, which is disposed in the bead portion 4 between the sidewall rubber 3G and the tire carcass 6. The first edge rubber 4G1, by being disposed from the sidewall portion 3 to the bead portion 4, improves the flexural rigidity of the sidewall portion, etc. Therefore, the tire 1 of this embodiment can perform excellent handling stability as a racing tire.

[0067] In this embodiment, the bead rubber 4G may include a second bead rubber 4G2, which overlaps the outer side of the canvas bead wrap 45 in the tire radial direction within the inner region 41. In this embodiment, the second bead rubber 4G2 is disposed adjacent to the first portion 45a and the second portion 45b of the canvas bead wrap 45. This second bead rubber 4G2 further effectively reinforces the bead portion 4 on the toe Bt side, thus further suppressing damage to the toe Bt.

[0068] There is no particular limitation on the complex elastic modulus of the edge rubber 4G, as long as it is greater than that of the sidewall rubber 3G. In a preferred embodiment, in order to achieve the effect of preventing rim drift without compromising the handling stability of the tire 1 at high speeds, it is effective to establish a relationship between the rigidity of the inner region 41 and the rigidity of the outer region 42, and to set a certain rigidity difference between them. More specifically, the ratio (E*s / E*c) of the complex elastic modulus E*s of the sidewall rubber 3G to that of the edge rubber 4G is preferably 0.20 or less. On the other hand, when the ratio of the complex elastic modulus E*s of the sidewall rubber 3G to that of the edge rubber 4G is excessively reduced, it may be difficult to simultaneously achieve the effects of handling stability at high speeds and rim drift prevention. From this point of view, the ratio (E*s / E*c) is preferably 0.10 or more.

[0069] Compression ratio

[0070] In a preferred embodiment, the compression ratio is preferably 10% to 16% on the inner portion of the bead core 5 in the tire radial direction. In this specification, the compression ratio is a value obtained by dividing the thickness of the core portion 46 located inside the bead core 5 in the tire radial direction by the thickness before rim assembly. For convenience, in this specification, the compression ratio is determined on the tire radial direction line CL passing through the center 5c of the bead core 5.

[0071] As mentioned above, the static friction coefficient of rubber is pressure-dependent. Therefore, by optimizing the pressure of the core portion 46, the frictional force can be maximized. As a result of various experiments, under the premise of the bead structure of the tire 1 of the present invention, when the compression rate of the core portion 46 during rim assembly is 10% to 16%, the frictional force between the core portion 46 and the bead seat surface Rs is maximized, thereby achieving a higher rim misalignment suppression effect.

[0072] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific disclosures above, and can be implemented by various modifications within the scope of the technical concept described in the technical solution.

[0073] [Example]

[0074] The following describes more specific and non-limiting embodiments of the present invention.

[0075] A prototype with Figure 1 and Figure 2 The basic structure of the racing car pneumatic tire shown was subjected to the following tests. In addition, for comparison, the same tests were also performed on Comparative Example 1, where the entire area of ​​the bottom of the tire bead was covered with canvas bead fabric, and Comparative Example 2, where the entire area of ​​the bottom of the tire bead was covered with rubber bead fabric.

[0076] [Tooth injury resistance]

[0077] After the prototype tire was installed on the rim, the disassembly and reassembly process was repeated three times to check for damage to the bead area, including the toe. In Table 1, the results are scored as 100 for cases without damage, and for cases with damage, the score corresponding to the degree of damage is subtracted from 100.

[0078] [Handling Stability]

[0079] A prototype tire was mounted on a rim (size: 18×13.0J) without applying rim offset inhibitor, and the tire was inflated with air and the internal pressure adjusted to 180 kPa. This tire / rim assembly was then mounted on all wheels of a racing vehicle (FIA-GT3 vehicle). Furthermore, a professional driver drove the vehicle at full throttle on the track, and the handling stability was evaluated using the driver's senses. In Table 1, the results are expressed as scores, with higher values ​​indicating better performance.

[0080] [Rim Misalignment Resistance]

[0081] After the aforementioned handling stability test drive, the circumferential offset of the tire from the rim was measured. For the measurement, the rim and tire were marked beforehand, and the positional offset of these marks was measured after driving. In Table 1, the results are expressed as indicators, with larger values ​​indicating better performance.

[0082] The test results are shown in Table 1.

[0083] [Table 1]

[0084]

[0085] As shown in Table 1, compared with the tires of Comparative Examples 1 and 2, the tires of the embodiments can suppress damage to the tire toe during rim assembly and can suppress severe rim misalignment during driving.

[0086] Next, the same tests were performed on the tire of the present invention with different tire specifications (Examples 1 to 8). The test results are shown in Table 2.

[0087] [Table 2]

[0088]

[0089] As can be seen from Table 2, the tires of Examples 1 to 8 exhibited good performance.

[0090] Furthermore, the same tests were conducted on the tire of the present invention by changing the compression ratio (Examples 9 to 11). The test results are shown in Table 3.

[0091] [Table 3]

[0092]

[0093] As can be seen from Table 3, the tires of Examples 9 to 11 exhibited good performance.

Claims

1. A pneumatic tire, comprising: Fetal face; A pair of tire sidewalls; A pair of bead portions, in which bead cores are embedded respectively; A ring-shaped tire carcass disposed between the pair of bead portions; and Sidewall rubber, which is disposed on the outer side of the tire carcass in each of the pair of sidewall portions along the tire axial direction. The pair of bead portions each have a bead bottom surface that contacts the bead seat surface of the rim. The bottom surface of the tire bead includes: The inner region along the tire axial direction, which includes the tire toe; and The outer region along the tire's axial direction, including the heel. The inner area is formed by covering the tire bead with canvas. The outer region is formed by the sidewall rubber extending inward from the sidewall portion in the radial direction of the tire. Each of the pair of bead portions is provided with edge rubber having a higher complex elastic modulus than that of the sidewall rubber. The sidewall rubber includes a first sidewall rubber, which is disposed between the sidewall rubber and the tire body. Each of the pair of bead portions is provided with edge rubber having a higher complex elastic modulus than that of the sidewall rubber. The edge rubber includes a second edge rubber that overlaps the inner region of the canvas bead wrapping in the tire radial direction outside. The complex elastic modulus E of the sidewall rubber s and the complex elastic modulus E of the edge rubber c to E s / E c is 0.10 to 0.

20.

2. The pneumatic tire according to claim 1, wherein, The axial length of the tire in the inner region is 2 mm or more.

3. The pneumatic tire according to claim 1 or 2, wherein, When the length of the tire axial direction from the toe to the center of the bead core is set as Lc, and the width of the tire axial direction of the bead core is set as Wb, the length of the tire axial direction of the inner region is less than or equal to Lc+0.5Wb.

4. The pneumatic tire according to claim 1 or 2, wherein, The canvas bead wrapping fabric includes: Part 1, which extends axially along the tire in the inner region; and Part 2 extends outward from the toe in the radial direction of the tire.

5. The pneumatic tire according to claim 1 or 2, wherein, The canvas bead wrapping includes a third portion that overlaps the outer region of the sidewall rubber in the tire radial direction.

6. The pneumatic tire according to claim 5, wherein, The canvas bead wrapping includes a fourth part, which is connected to the third part and extends outward in the radial direction of the tire.

7. The pneumatic tire according to claim 1 or 2, wherein, The complex elastic modulus of the sidewall rubber is 2 MPa to 10 MPa.

8. The pneumatic tire according to claim 1 or 2, wherein, In the outer region, the thickness of the sidewall rubber is 0.5 mm to 2.0 mm.

9. The pneumatic tire according to claim 1 or 2, wherein, The compression ratio is 10% to 16% on the inner portion of the bead core in the tire radial direction. The compression ratio is a value obtained by dividing the thickness of the core portion located inside the bead core in the tire radial direction by the thickness before rim assembly. The compression ratio is determined on a line in the tire radial direction passing through the center of the bead core.

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