TIRES

Abstract

A pneumatic tire that includes a recessed section 20 which extends continuously in the circumferential direction in an outer tire surface of at least one of the sidewall sections 2. In a meridian cross-section, an area A of a region enclosed by the outer contours of the side wall section 2 and the bead section 3 and a tangent L1, an area S of a region enclosed by the outer contours of the side wall section 2 and the bead section 3, a body section 4a, a perpendicular line L2 and a perpendicular line L3, and a thickness G1 of the bead filler 6, measured along the perpendicular line L2, satisfy a relationship of 0.10 × (G1 - 17) ≤ A / (S + A) ≤ 0.05 × (G1 - 10), where the tangent L1 is a straight line placed in contact with the outer contours of the side wall section 2 and the bead section 3, and a contact point P1 is a point,where the tangent L1 and the outer contour of the sidewall section 2 are in contact with each other, the perpendicular line L2 is a straight line that passes through the folded edge of the carcass layer 4 and perpendicularly intersects the body section 4a of the carcass layer 4, the perpendicular line L3 is a straight line that passes through the contact point P1 and perpendicularly intersects the body section 4a of the carcass layer 4.

Description

Technical area

[0001] The present invention relates to a pneumatic tire including a recessed portion near a bead portion to reduce tire weight. State of the art

[0002] In recent years, tire weight reduction has been pursued to increase the effective load capacity with a view to improving the transportation efficiency of vehicles. As a method for reducing tire weight, it has been proposed to reduce the amount of rubber in a bead portion by providing a recessed portion near the bead portion (see, for example, Patent Document 1). However, when such a recessed portion is provided, the durability of the bead portion adversely decreases due to increased deformation resulting from the reduction in the amount of rubber.In view of this, measures are required to favorably maintain the durability of the bead portion by suppressing the deformation of the bead portion (particularly in the vicinity of the carcass edge), even in a pneumatic tire provided with a recessed portion near the bead portion for reducing the tire weight. Literature listPatent literature

[0003] Patent Document 1: JP 5390392 B Brief description of the inventionTechnical problem

[0004] An object of the present invention is to provide a pneumatic tire in which a reduction in tire weight can be achieved while maintaining favorable durability of the bead portion. Solution to the problem

[0005] To achieve the above-mentioned object, a pneumatic tire of the present invention includes: a tread portion extending in the tire circumferential direction and having a ring shape; a pair of sidewall portions arranged on both sides of the tread portion; a pair of bead portions arranged on an inner side of the sidewall portions in a tire radial direction, respectively; a bead core arranged on each bead portion; a bead filler arranged on an outer side of the bead core in the tire radial direction; and at least one carcass layer arranged between the pair of bead portions, the carcass layer comprising a body portion turned up from a tire inner side to a tire outer side around the bead core and the bead filler arranged on each bead portion and located between the pair of bead portions, and a turned-up portion.which is turned up on an outer side of the bead core and the bead filler in a tire width direction, wherein a width between the pair of bead portions in a rim-unmounted state is set to a specified rim width, the pneumatic tire comprising a recess portion which is continuous in the tire circumferential direction in a tire outer surface on an outer side of a turned-up edge of the carcass layer of at least one of the sidewall portions in the tire radial direction and on an inner side of a tire maximum width position in the tire radial direction, the recess portion having a contour including a plurality of arcs having different radii of curvature in a meridian cross-section, wherein in the meridian cross-section, an area A (unit: mm, 2) of an area surrounded by outer contours of the sidewall portion and the bead portion and a tangent L1, an area S (unit: mm 2) of an area surrounded by the outer contours of the sidewall portion and the bead portion, the body portion, a vertical line L2 and a vertical line L3, and a thickness G1 (unit: mm) of the bead filler measured along the vertical line L2 satisfy a relationship of 0.10 × (G1 - 17) ≤ A / (S + A) ≤ 0.05 × (G1 - 10), where the tangent L1 is a straight line put in contact with the outer contours of the sidewall portion and the bead portion, a contact point P1 is a point at which the tangent L1 and the outer contour of the sidewall portion are in contact with each other, the vertical line L2 is a straight line passing through the turned-up edge of the carcass layer and perpendicularly intersecting the body portion, the vertical line L3 is a straight line passing through the contact point P1 and the body section cuts vertically. Advantageous effects of the invention

[0006] As described above, in the present invention, the tire circumferentially continuous recess portion is provided in the vicinity of at least one of the bead portions, and thus the tire weight can be reduced by reducing the amount of rubber in the vicinity of the bead portion.On the other hand, since the above-described recessed portion is arranged on the outer side in the tire radial direction of the turned-up edge of the carcass layer and on the inner side of the maximum tire width position in the tire radial direction in the sidewall portion, and the area (area A) of the recessed portion, the rubber amount (area S) on the outer side of the carcass edge in the radial direction, and the thickness G1 of the bead filler are set to have the above-described relationship, the deformation in the vicinity of the carcass edge due to the recessed portion can be dispersed, and the durability of the bead portion can be favorably ensured.

[0007] In the present invention, the outer contours of the sidewall portion and the bead portion located between a contact point P2 and a point P3 are preferably located on an outer side of a straight line L4 in the tire width direction, where the contact point P2 is a point where the tangent L1 and the outer contour of the bead portion are in contact with each other, and the point P3 is a point 10 mm away from the contact point P2 on an outer side in the tire radial direction along the outer contours of the sidewall portion and the bead portion, with the straight line L4 connecting the contact point P2 and the point P3. In this way, the shape of the recessed portion (outer contour) is improved, and the amount of rubber near the carcass edge can be ensured, which is beneficial for improving the durability of the bead portion.

[0008] In the present invention, a ratio G2 / G1 of a thickness G2 (unit: mm) of the bead filler measured on a straight line passing through a contact point P2 and perpendicularly intersecting the body portion with respect to the thickness G1 preferably satisfies a relationship of 0.55 ≤ G2 / G1 ≤ 0.90, and a ratio S1 / S of an area S1 (unit: mm 2 ) of an area occupied by the bead filler in the area S with respect to the area S satisfies a relationship of 0.25 ≤ S1 / S ≤ 0.50, where the contact point P2 is a point where the tangent L1 and the outer contour of the bead portion are in contact with each other. In this way, the volume of the bead filler with excellent fatigue resistance and bursting properties can be ensured, which is beneficial for improving the durability of the bead portion.

[0009] In the present invention, the bead filler preferably has a two-layer structure including an upper bead filler and a lower bead filler, and the upper bead filler has a breaking elongation of 400% or more. By using a bead filler with such a high breaking elongation, bursting near the carcass edge due to repeated deformation during rolling is suppressed, which is beneficial for improving the durability of the bead portion.

[0010] In the present invention, the upper bead filler preferably has a modulus of elasticity at 60°C of 4.0 MPa or more and 8.0 MPa or less, and the lower bead filler has a modulus of elasticity at 60°C of 14.0 MPa or more and 20.0 MPa or less. Thus, when the bead filler has a two-layer structure, the physical properties of the upper bead filler and the lower bead filler are improved, which is advantageous in terms of improving the durability of the bead portion.

[0011] In the present invention, an area S2 of the upper bead filler and an area S3 of the lower bead filler preferably satisfy the relationship 0.30 ≤ S3 / S2 ≤ 0.80. The upper bead filler and the lower bead filler provided with a good balance as described above are advantageous for improving the durability of the bead portion.

[0012] In the present invention, a distance G3 between the turned-up edge and the tire outer surface, measured along the vertical line L2, is preferably 7.0 mm or more and 14.0 mm or less, and a distance G4 between an outer surface of the recessed portion and the turned-up edge, measured along an extension line of the turned-up portion, is 10.0 mm or more and 40.0 mm or less. In this way, the clearance between the carcass edge and the outer contour of the tire can be secured, and the deformation in the area between the carcass edge and the outer contour of the tire can be dispersed, which is advantageous for the durability of the bead portion.

[0013] In the present invention, a crack suppression rubber is preferably arranged to cover the turned-up edge, and the crack suppression rubber has a breaking elongation of 400% or more. By disposing the crack suppression rubber and increasing the breaking elongation of the crack suppression rubber as described above, bursting near the carcass edge due to repeated deformation during rolling can be suppressed, which is beneficial for improving the durability of the bead portion.

[0014] In the present invention, a side rubber of the sidewall portion preferably has a breaking elongation of 450% or more and a Young's modulus at 60°C of 2.5 MPa or more and 5.5 MPa or less. By increasing the breaking elongation of the side rubber as described above, bursting near the carcass edge due to repeated deformation during rolling can be suppressed, which is advantageous for improving the durability of the bead portion. In addition, the side rubber with such a large Young's modulus can compensate for the reduced lateral rigidity caused by the provision of the recessed portion, which is advantageous for reducing the deformation of the bead portion and improving the durability.

[0015] Preferably, the present invention further comprises an organic fiber reinforcing layer on an outer side of the turned-up portion of the carcass layer in the tire width direction. An end portion of the organic fiber reinforcing layer on an outer side in the tire radial direction is located on the outer side of the turned-up edge in the tire radial direction, an end portion of the organic fiber reinforcing layer on an inner side in the tire radial direction is located on the inner side of a center of the bead core in the tire radial direction, and an end portion of the organic fiber reinforcing layer on the outer side in the tire radial direction is 6 mm or more away from the recess portion.With the organic fiber reinforcing layer provided and arranged as described above, deformation due to bending can be suppressed, which is advantageous in terms of improving durability by suppressing deformation in the vicinity of the carcass edge.

[0016] Preferably, the present invention further includes a steel reinforcing layer disposed along the outer surfaces of the body portion and the turned-up portion of the carcass layer. An end portion of the steel reinforcing layer on the turned-up portion side is disposed at a position 5 mm to 25 mm away from a position of the turned-up edge on an inner side in the tire radial direction, and an end portion of the steel reinforcing layer on the body portion side is disposed at a position 5 mm to 25 mm away from a position of the turned-up edge on an outer side in the tire radial direction.When the steel reinforcing layer is provided and arranged as described above, the deformation of the bead portion due to bending can be suppressed by improving the lateral rigidity, which is advantageous in improving the durability of the bead portion.

[0017] Note that in the present invention, the "specified rim width" is a width of a specified rim ("Application Rim" specified in JATMA, "Design Rim" specified in TRA, or "Measuring Rim" specified in ETRTO). In the present invention, the elongation at break of each section is a value (unit: %) measured at room temperature (23°C) in accordance with JIS K6251. Furthermore, the elastic modulus at 60°C of each section is a value (unit: MPa) measured with a viscoelastic spectrometer under the conditions of an initial deformation of 10%, an amplitude of ±2%, a frequency of 20 Hz, and a temperature of 60°C in accordance with JIS K6394. Brief description of the drawings Fig. 1 is a meridian cross-sectional view illustrating an example of a pneumatic tire according to an embodiment of the present invention. Fig.2 is an enlarged explanatory diagram of a bead portion of the pneumatic tire according to the embodiment of the present invention. Fig. 3 is an enlarged explanatory diagram of a bead portion of the pneumatic tire according to another embodiment of the present invention. Description of embodiments

[0018] A configuration of the present invention will be explained in detail below with reference to the accompanying drawings.

[0019] As in Fig. 1, a pneumatic tire of the present invention includes a tread portion 1, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 each arranged on the inner side of the sidewall portion 2 in the tire radial direction. In Fig.1, the reference symbol CL stands for the tire equator. It should be noted that the tread portion 1, the sidewall portion 2 and the bead portion 3, although in Fig. 1, which is a meridian cross-sectional view, not illustrated, each extend in the tire circumferential direction and have a ring shape, thereby forming an annular basic structure of the pneumatic tire. The following description using Fig. 1 is essentially based on the meridian cross-sectional shape illustrated in the drawing, with each tire component extending annularly in the tire circumferential direction. Note that the meridian cross-sectional view illustrated in the drawing represents a state in which the width between the pair of bead portions 3 is set to a specific rim width in a state not mounted on the rim, and the following description is based on a structure in this state.

[0020] A carcass layer 4 is disposed between the pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction and folded back from a vehicle inner side to a vehicle outer side around a bead core 5 disposed in each bead portion 3. Furthermore, a bead filler 6 is disposed over the outer periphery of the bead core 5, and the bead filler 6 is enclosed by a body portion 4a and a folded-back portion 4b of the carcass layer 4.

[0021] A belt layer 7, which consists of a multitude of layers (four layers in Fig.1) is embedded on an outer peripheral side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords (steel cords) oriented in a predetermined direction. The plurality of belt layers 7 includes a crossed belt pair. The crossed belt pair is a combination of at least two belt layers configured such that the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set in the range of 10° to 40° and that the reinforcing cords intersect with each other, with the inclination directions of the reinforcing cords being opposite between the layers.In addition to the crossed belt pair, a high-angle belt layer in which the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in the range of 40° to 70°, a protective belt layer arranged as an outermost layer and whose width is 85% or less of that of the other belt layers, a circumferential reinforcing layer in which the angle of the reinforcing cord with respect to the tire circumferential direction is set in the range of 0° to 5°, and the like may also be optionally provided. For example, in . Fig.1, a protective belt layer is arranged as the outermost layer, a large-angle belt layer is arranged on the innermost layer, and the other two layers are the crossed belt pair. Further, a belt reinforcing layer (not illustrated) may be provided on the outer peripheral side of the belt layer 7. The belt reinforcing layer may be composed of, for example, an organic fiber cord oriented in the tire circumferential direction. In the belt reinforcing layer 8, the angle with respect to the tire circumferential direction in the organic fiber cord is set to, for example, 0° to 5°.

[0022] In the tread portion 1, a tread rubber layer 11 is disposed on the outer peripheral side of the aforementioned tire components (the carcass layer 4, the belt layer 7, and the belt cover layer). A side rubber layer 12 is disposed on the outer peripheral side (outer side in the tire width direction) of the carcass layer 4 in the sidewall portion 2. A rim cushion rubber layer 13 is disposed on the outer peripheral side (outer side in the tire width direction) of the carcass layer 4 in the bead portion 3.

[0023] In the tire of the present invention, a recessed portion 20 is provided continuously in the outer surface of the sidewall portion 2 and the bead portion 3 on at least one side in the tire circumferential direction. The recessed portion 20 is located on the outer side of the turned-up edge of the carcass layer 4 in the tire radial direction and on the inner side of a tire maximum width position P in the tire radial direction. In other words, a contact point P1 described later is located on the inner side of the tire maximum width position P in the tire radial direction, and a contact point P2 described later is located on the outer side of the turned-up edge of the carcass layer 4 in the tire radial direction. With this recessed portion 20, the tire weight can be reduced by reducing the amount of rubber near the bead portion 3.

[0024] The contour of the recess portion 20 in the meridian cross-section is composed of a plurality of arcs with different radii of curvature and is smoothly curved. For example, the contour of the recess portion 20 may be formed by a combination of an arc protruding outward in the tire width direction and an arc protruding inward in the tire width direction. Specifically, among the plurality of arcs constituting the contour of the recess portion 20, the innermost arc in the tire radial direction and the outermost arc in the tire radial direction preferably protrude toward the outside in the tire width direction.

[0025] As in Fig.2, in the meridian cross section, a straight line in contact with the outer contours of the sidewall portion 2 and the bead portion 3 is set as a tangent L1, the point at which the tangent L1 and the outer contour of the sidewall portion 2 touch is set as a contact point P1, a straight line passing through the turned-up edge of the carcass layer 4 and perpendicularly intersecting the body portion 4a is set as a perpendicular line L2, and a straight line passing through the contact point P1 and perpendicularly intersecting the body portion 4a is set as a perpendicular line L3. In this case, an area A (unit: mm 2 ) of the area surrounded by the outer contours of the side wall portion 2 and the bead portion 3 and the tangent L1 (in the drawing the hatched area), an area S (unit: mm 2) of the area surrounded by the outer contours of the sidewall portion 2 and the bead portion 3, the body portion 4a, the vertical line L2 and the vertical line L3 (in the drawing, the hatched area), and a thickness G1 (unit: mm) of the bead filler 6 measured along the vertical line L2, the relationship 0.10 × (G1 - 17) ≤ A / (S + A) ≤ 0.05 × (G1 - 10).

[0026] With such a structure, it is possible to advantageously maintain the durability of the bead portion 3, which is feared to be deteriorated when the recess portion 20 is provided near the bead portion to reduce the tire weight.Specifically, since the recessed portion 20 is disposed on the outer side of the turned-up edge of the carcass layer 4 in the tire radial direction and on the inner side of the maximum tire width position P in the tire radial direction in the sidewall portion 2, and the area (area A) of the recessed portion 20, the rubber amount (area S) on the outer side of the carcass edge in the radial direction, and the thickness G1 of the bead filler 6 are set to have the relationship described above, the thickness G1 of the bead filler 6 can be increased in proportion to the area of ​​the recessed portion 20, and the durability of the bead portion 3 can be favorably ensured by dispersing the deformation in the vicinity of the carcass edge caused by the provision of the recessed portion 20.

[0027] When the area A, the area S, and the thickness G1 of the bead filler 6 have a relationship of 0.10 × (G1 - 17) > A / (S + A), the rubber for dispersing deformation is insufficient, and the effect of improving the durability of the bead portion 3 cannot be sufficiently expected. When the area A, the area S, and the thickness G1 of the bead filler 6 have a relationship of A / (S + A) > 0.05 × (G1 - 10), the area of ​​the recessed portion 20 cannot be sufficiently ensured, and the effect of reducing tire weight cannot be sufficiently expected. Preferably, the area A, the area S, and the thickness G1 of the bead filler 6 satisfy the relationship of 0.10 × (G1 - 16) ≤ A / (S + A) ≤ 0.05 × (G1 - 12). It should be noted that the value of the ratio A / (S + A) is preferably 0.05 to 0.25, but is not limited to this.

[0028] As in Fig.As illustrated in Figure 3, when the point where the tangent L1 and the outer contour of the bead portion 3 are in contact with each other is set as the contact point P2, the outer contours of the sidewall portion 2 and the bead portion 3 located between the contact point P2 and a point P3 are preferably located on the outer side in the tire width direction as a straight line L4 connecting the contact point P2 and the point P3. The point P3 is a point 10 mm away from the contact point P2 on the outer side in the tire radial direction along the outer contours of the sidewall portion 2 and the bead portion 3.In this way, the outer contour between the point P3 and the contact point P2 protrudes to the outside in the tire width direction, and the shape (outer contour) of the recessed portion 20 is improved, and thus the amount of rubber near the carcass edge can be ensured, which is beneficial for improving the durability of the bead portion 3.

[0029] As in Fig.Further, as illustrated in FIG. 3, the outer contours of the sidewall portion 2 and the bead portion 3 located between the contact point P2 and a point P4 are preferably located on an outer side in the tire width direction as a straight line L5 connecting the contact point P2 and the point P4. The point P4 is a point 15 mm away from the contact point P2 on the outer side in the tire radial direction along the outer contours of the sidewall portion 2 and the bead portion 3. In this way, the outer contour between the point P4 and the contact point P2 also protrudes toward the outer side in the tire width direction, and the shape (outer contour) of the recess portion 20 is improved, and thus the amount of rubber near the carcass edge can be secured, which is beneficial for improving the durability of the bead portion 3.

[0030] As in Fig.2, when the point where the tangent L1 and the outer contour of the bead portion 3 are in contact with each other is set as the contact point P2, and the thickness of the bead filler 6 measured on a straight line passing through the contact point P2 and perpendicularly intersecting the body portion 4a is set as G2 (unit: mm), the ratio G2 / G1 of the thickness G2 to the thickness G1 preferably satisfies a relationship of 0.55 ≤ G2 / G1 ≤ 0.90, more preferably satisfying a relationship of 0.60 ≤ G2 / G1 ≤ 0.85. In this way, the volume of the bead filler 6 with excellent flexural and bursting properties can be ensured, which is beneficial for improving the durability of the bead portion 3. If G2 / G1 is less than 0.55, the amount of rubber is insufficient and the deformation near the carcass edge cannot be sufficiently suppressed; moreover, sufficient improvement in durability cannot be expected.If G2 / G1 is greater than 0.90, the amount of rubber in the side part is insufficient and defects such as ozone cracks are likely to occur.

[0031] If the area occupied by the bead filler 6 in the above-described area S is defined as area S1 (unit: mm 2), the ratio S1 / S of the area S1 to the area S preferably satisfies a relationship of 0.25 ≤ S1 / S ≤ 0.50, more preferably satisfies a relationship of 0.30 ≤ S1 / S ≤ 0.45. In this way, the volume of the bead filler 6 with excellent flexural fatigue and bursting properties can be ensured, which is beneficial for improving the durability of the bead portion 3. If S1 / S is less than 0.25, the amount of rubber is insufficient and the deformation near the carcass edge cannot be sufficiently suppressed; further, sufficient improvement in durability cannot be expected. If S1 / S is greater than 0.50, the amount of rubber in the side part is insufficient and defects such as ozone cracking are likely to occur.

[0032] As in Fig.2, the ratio H2 / H1 is preferably 1.1 or more and 1.5 or less when the distance along the tire radial direction from the innermost point (end of the bead toe) of the bead portion 3 in the tire radial direction to the carcass edge is set as H1 and the distance along the tire radial direction from the innermost point (end of the bead toe) of the bead portion 3 in the tire radial direction to the contact point P is set as H2. In this way, the shape of each portion in the bead portion 3 is further improved, which is beneficial to improving the durability of the bead portion 3.

[0033] In the present invention, the bead filler 6 preferably has a two-layer structure composed of an upper bead filler 6a and a lower bead filler 6b. When the bead filler 6 having such a two-layer structure is used, the elongation at break of the upper bead filler 6a is preferably 400% or more, more preferably 450% or more. By using the bead filler 6 with such a high elongation at break, bursting near the carcass edge due to repeated deformation during rolling is suppressed, which is beneficial for improving the durability of the bead portion. If the elongation at break of the upper bead filler 6a is less than 400%, the rubber around the carcass is easily cracked due to repeated deformation, making it difficult to sufficiently improve the durability of the bead portion 3.Note that the upper limit of the elongation at break of the upper bead filler 6a is preferably, for example, 800% or less, but is not limited thereto. Furthermore, the range of the elongation at break of the lower bead filler 6b is preferably, for example, 50% to 250%, but is not limited thereto.

[0034] When the bead filler 6 having a two-layer structure is used as described above, the elastic modulus at 60 °C of the upper bead filler 6a is preferably 4.0 MPa or more and 8.0 MPa or less, more preferably 4.5 MPa to 7.5 MPa. In addition, the elastic modulus of the lower bead filler 6b at 60 °C is preferably 14.0 MPa or more and 20.0 MPa or less, more preferably 15.0 MPa or more and 19.0 MPa or less. In this way, when the bead filler 6 has a two-layer structure, the physical properties of the upper bead filler 6a and the lower bead filler 6b are improved, which is advantageous in terms of improving the durability of the bead portion. If the elastic modulus of the upper bead filler 6a and the lower bead filler 6b at 60°C is less than the above-described range, the deformation of the bead portion 3 under load is large and the distortion of the carcass edge is also large, and thus the durability improvement effect cannot be sufficiently expected.If the elastic modulus of the upper bead filler 6a and the lower bead filler 6b at 60 °C is higher than the above-described range, the elongation at break of the bead filler 6 cannot be improved and hence the effect of improving the durability cannot be sufficiently expected.

[0035] When the bead filler 6 having a two-layer structure is used as described above, the area S2 of the upper bead filler 6a and the area S3 of the lower bead filler 6b preferably satisfy a relationship of 0.30 ≤ S3 / S2 ≤ 0.80, more preferably a relationship of 0.40 ≤ S3 / S2 ≤ 0.70. The upper bead filler 4a and the lower bead filler 4b provided with a good balance in this way are advantageous for improving the durability of the bead portion 3. In particular, when the breaking elongation of the upper bead filler 4a is large, the area of ​​the upper bead filler 4a is large, and the deformation near the carcass edge can be dispersed, thereby improving the durability of the bead portion 3. On the other hand, when the elastic modulus of the lower bead filler 4b is high, the deformation of the entire bead portion 3 under load is suppressed, thereby improving the durability of the bead portion 3.When the areas are set as described above, the balance of the areas of the upper bead filler 4a and the lower bead filler 4b is favorable and the above-described effect can be effectively achieved, and thus the durability of the bead portion 3 as a whole can be increased.

[0036] As in Fig.3, when the distance between the turned-up edge and the tire outer surface, measured along the vertical line L2, is set as G3, and the distance between the turned-up edge and the outer surface of the recessed portion 20, measured along the extension line of the turned-up portion 4b, is set as G4, the distance G3 is preferably 7.0 mm or more and 14.0 mm or less, more preferably 8.0 mm or more and 13.0 mm or less, and the distance G4 is preferably 10.0 mm or more and 40.0 mm or less, more preferably 15.0 mm or more and 37.0 mm or less. In this way, the distance between the carcass edge and the outer contour of the tire can be sufficiently secured, and the deformation in the area between the carcass edge and the outer contour of the tire can be dispersed, which is advantageous for the durability of the bead portion 3.If the distances G3 and G4 are smaller than the above-described range, the rubber quantity cannot be sufficiently ensured and the deformation of the carcass edge cannot be sufficiently distributed, and consequently, the durability improvement effect cannot be sufficiently expected. If the distances G3 and G4 are larger than the above-described range, the tire weight reduction effect cannot be sufficiently expected.

[0037] In the present invention, the elongation at break of the rubber of the side rubber layer 12 is preferably 450% or more, more preferably 500% or more. In addition, the elastic modulus of the rubber of the side rubber layer 12 at 60°C is preferably 2.5 MPa or more and 5.5 MPa or less, more preferably 3.5 MPa or more and 5.0 MPa or less. By increasing the elongation at break of the side rubber in the manner described above, bursting near the carcass edge due to repeated deformation during rolling can be suppressed, which is advantageous in improving the durability of the bead portion. In addition, the side rubber with such a large modulus of elasticity can compensate for the reduced lateral rigidity by providing the recessed portion, which is advantageous in reducing the deformation of the bead portion and improving the durability.If the breaking elongation of the rubber of the side rubber layer 12 is less than 450%, the rubber around the carcass is easily cracked due to repeated deformation during rolling, making it difficult to sufficiently improve the durability of the bead portion 3. Note that the upper limit of the breaking elongation of the side rubber layer 12 is preferably, for example, 800% or less, but not limited thereto. If the elastic modulus of the rubber of the side rubber layer 12 at 60°C is less than 2.5 MPa, the lateral rigidity cannot be sufficiently ensured, while if it is greater than 5.5 MPa, the breaking elongation of the side rubber layer 12 cannot be advantageously maintained, and thus the durability improvement effect cannot be sufficiently expected.

[0038] In the present invention, as in Fig.3, a crack suppression rubber layer 14 may be disposed so as to cover the turned-up edge of the carcass layer 4. It is preferable to dispose the crack suppression rubber layer 14 in contact with both the side rubber layer 12 and the rim cushion rubber layer 13. Further, when a steel reinforcing layer 21 described later is provided, it is preferable to dispose it so as to cover not only the turned-up edge of the carcass layer 4 but also the end portion of the steel reinforcing layer 21. Likewise, when an organic fiber reinforcing layer 22 described later is provided, it is preferable to dispose it so as to cover not only the turned-up edge of the carcass layer 4 but also the end portion of the organic fiber reinforcing layer 22.When such a crack suppression rubber layer 14 is provided, it is preferable to set its elongation at break to 400% or more, more preferably 450% or more. With the crack suppression rubber layer 14 having such a high elongation at break, bursting near the carcass edge due to repeated deformation during rolling can be suppressed, which is beneficial for improving the durability of the bead portion. If the elongation at break of the crack suppression rubber layer 14 is less than 400%, the rubber around the carcass is easily cracked due to repeated deformation during rolling, making it difficult to sufficiently improve the durability of the bead portion 3. Note that it is preferable to set the upper limit of the elongation at break of the side rubber layer 14 to, for example, 800% or less, but not limited thereto.

[0039] In the present invention, as in Fig.2, the steel reinforcing layer 21 may be disposed along the outer surface of the body portion 4a and the turned-up portion 4b of the carcass layer 4. When the steel reinforcing layer 21 is provided, its end portion on the turned-up portion 4b side is preferably separated from the position of the turned-up edge to the inside in the tire radial direction, and the separation distance along the tire radial direction between the turned-up edge and the end portion of the steel reinforcing layer 21 on the turned-up portion 4b side is preferably 5 mm to 25 mm, more preferably 7 mm to 20 mm.Furthermore, the end portion on the body portion 4a side is preferably separated from the position of the folded edge to the outside in the tire radial direction, and the separation distance along the tire radial direction between the folded edge and the end portion of the steel reinforcing layer 21 on the body portion 4a side is preferably 5 mm to 25 mm, more preferably 7 mm to 20 mm. When the steel reinforcing layer 21 is provided and arranged as described above, the deformation of the bead portion due to bending can be suppressed by improving the lateral rigidity, which is beneficial for improving the durability of the bead portion.

[0040] In the present invention, as in Fig.2, the organic fiber reinforcing layer 22 may be disposed on the outer side of the turned-up portion 4b of the carcass layer 4 in the tire width direction. Note that when the above-described steel reinforcing layer 21 is provided, it is preferable to provide the organic fiber reinforcing layer 22 preferably on the outer peripheral side (outer side in the tire width direction) of the steel reinforcing layer 21, as illustrated in the drawing. When the organic fiber reinforcing layer 22 is provided, its end portion on the outer side in the tire radial direction is preferably located on the outer side of the turned-up edge in the tire radial direction, and its end portion on the inner side in the tire radial direction is located on the inner side of the center of the bead core 5 in the tire radial direction.Furthermore, an end portion of the organic fiber reinforcing layer 22 on the outer side in the tire radial direction is 6 mm or more away from the recessed portion. With the organic fiber reinforcing layer 22 provided and arranged as described above, deformation due to bending can be suppressed, which is advantageous in terms of improving durability by suppressing deformation near the carcass edge.

[0041] The present invention is further described below with examples, but the scope of the present invention is not limited to the following examples. Examples

[0042] Thirty-five kinds of pneumatic tires of Prior Art Example 1, Comparative Example 1 and Examples 1 to 33 having a tire size of 11R22.5, Fig.1 and the structures near the bead portion as defined in Tables 1 to 3.

[0043] Regarding “presence / absence of a recessed portion” in Tables 1 to 4, a case where a recessed portion continuous in the tire circumferential direction is present in the tire outer surface at the outer side of the turned-up edge of the carcass layer of the sidewall portion in the tire radial direction and at the inner side of the maximum tire width position in the tire radial direction is shown in Fig.1, is indicated as "Present," and a case where such a recessed portion is not present is indicated as "Not Present." Note that a case where the recessed portion is present only in one side wall portion is indicated as "Present (One Side)" (in the case where the recessed portion is present only in one side wall portion, other elements are numerical values ​​and the like of the side where the recessed portion is present).

[0044] "G1" in Tables 1 to 4 is the thickness G1 (unit: mm) of the bead filler measured along a straight line (the vertical line L2) passing through the turned-up edge of the carcass layer and perpendicularly intersecting the body portion of the carcass layer. "A / (S + A)" in Tables 1 to 4 is the area ratio calculated from the area A (unit: mm 2) of the area surrounded by the outer contours of the sidewall portion and the bead portion and the tangent L1 (a straight line placed in contact with the outer contours of the sidewall portion and the bead portion), and the area S (unit: mm 2 ) of the area surrounded by the outer contours of the sidewall portion and the bead portion, the body portion and the above-described perpendicular line L2 and perpendicular line L3 (a straight line passing through the point (the contact point P1) at which the above-described tangent L1 and the outer contour of the sidewall portion are in contact with each other and perpendicularly intersecting the body portion of the carcass layer).

[0045] The row "Outer contour shape with respect to straight line L4" in Tables 1 to 4 indicates a curved shape of the outer contour with respect to the straight line L4 (the protrusion direction with respect to the straight line L4). The straight line L4 is a line set to connect the contact point P2 and the point P3 when the contact point P2 is set as a point where the above-described tangent L1 and the outer contour of the bead portion are in contact with each other, and the point P3 is set as a point 10 mm away from the contact point P2 on the outer side in the tire radial direction along the outer contours of the sidewall portion and the bead portion.The case where the outer contours of the sidewall portion and the bead portion located between the contact point P2 and the point P3 are located on the outside of the straight line L4 in the tire width direction is indicated as "outside", and the other cases are indicated as "inside".

[0046] “S1 / S” in Tables 1 to 4 is the ratio of the area S1 (unit: mm 2), which is the area occupied by the bead filler in the above-described area S, to the area S. "G2 / G1" in Tables 1 to 4 is the ratio of the thicknesses G1 and G2 of the bead filler measured at various positions. G1 is a thickness of the bead filler measured along a straight line (the perpendicular line L2) passing through the turned-up edge of the carcass layer and perpendicularly intersecting the body portion of the carcass layer, and G2 is a thickness of the bead filler measured along a straight line passing through the above-described contact point P2 and perpendicularly intersecting the body portion of the carcass layer.

[0047] "Elongation at break (top side WF)" in Tables 1 to 4 is the elongation at break of the upper bead filler in the bead filler with the two-layer structure. "Elongation at break (side)" in Tables 1 to 4 is the elongation at break of the side rubber of the sidewall section. These are values ​​(unit: %) measured at room temperature (23 °C) according to JIS K6251 for the rubber of each section.

[0048] "Elastic modulus (top side WF)" in Tables 1 to 4 is the elastic modulus at 60°C of the upper bead filler in the bead filler with the two-layer structure, and "Elastic modulus (bottom side WF)" is the elastic modulus at 60°C of the lower bead filler in the bead filler with the two-layer structure. "Elastic modulus (side)" is the elastic modulus of the side rubber of the sidewall portion at 60°C. "Elastic modulus (cr)" is the elastic modulus of the rubber of the crack suppression rubber layer at 60°C. These are values ​​(unit: MPa) measured for the rubber of each section using a viscoelasticity spectrometer under the conditions of an initial deformation of 10%, an amplitude of ±2%, a frequency of 20 Hz, and a temperature of 60 °C according to JIS K6394.

[0049] "S3 / S2" in Tables 1 to 4 is a ratio of the area S2 of the upper bead filler and the area S3 of the lower bead filler. "G3" in Tables 1 to 4 is a distance between the turned-up edge and the outer tire surface, measured along the vertical line L2 described above. "G4" in Tables 1 to 4 is a distance between the turned-up edge and the outer surface of the recessed portion, measured along the extension line of the turned-up portion.

[0050] In the row "Presence / absence of organic fiber reinforcing layer" in Tables 1 to 4, "Presence" indicates a case where the organic fiber reinforcing layer is provided on the outer side of the turned-up portion of the carcass layer in the tire width direction, and "Absence" indicates a case where such organic fiber reinforcing layer is not provided.When the organic fiber reinforcing layer is provided, the end portion of the organic fiber reinforcing layer on the outer side in the tire radial direction is located on the outer side of the turned-up edge in the tire radial direction, the end portion of the organic fiber reinforcing layer on an inner side in the tire radial direction is located on the inner side of a center of the bead core in the tire radial direction, and the end portion of the organic fiber reinforcing layer on the outer side in the tire radial direction is 6 mm or more away from the recess portion.

[0051] In the row "Presence / absence of a steel reinforcing layer" in Tables 1 to 4, "Presence" indicates a case where the steel reinforcing layer is arranged along the outer surfaces of the turned-up portion and the body portion of the carcass layer, and "Absence" indicates a case where such a steel reinforcing layer is not arranged. When the steel reinforcing layer is provided, the end portion of the steel reinforcing layer on the rolled portion side is arranged at a position 5 mm to 25 mm away from the position of the turned-up edge on an inner side in the tire radial direction, and the end portion of the steel reinforcing layer on the body portion side is arranged at a position 5 mm to 25 mm away from the position of the turned-up edge on the outer side in the tire radial direction.

[0052] The amount of tire weight reduction and durability of the test tires described above were evaluated using the evaluation methods described below, and the results are shown in Tables 1 to 4. Amount of tire weight reduction

[0053] The weight (kg) of each test tire was measured, and the reduction amount relative to the prior art example 1 without a recessed portion (the absolute value of the difference from the tire weight of the prior art example 1) was calculated. The evaluation results are expressed as the actual numerical values ​​of the calculated reduction amount (kg). The higher the value, the greater the tire weight reduction effect. resistance

[0054] Each test tire was mounted on a rim specified in JATMA, mounted on a drum tester with a drum diameter of 1707 mm, inflated to the maximum air pressure specified in JATMA, and subjected to the maximum load specified in JATMA. The distance at which bulging or detachment of the bead portion was detected was measured after running at a running speed of 45 km / h. The evaluation results are expressed as index values, with the prior art example 1 set as 100. The higher the index value, the longer the distance before bulging or detachment of the bead portion is detected, that is, the more durable the bead portion is. Note that an index value of "90" or more means that sufficient durability was achieved compared to the prior art example 1 without a dimpled portion. [Table 1-I] Example of the prior art 1 Comparison example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Presence / absence of the deepening section Unavailable Available Available Available (one page) Available Available Available G1 mm 12 12 12 12 14 16 17 0,10 × (G1 - 17) -0,5 -0,5 -0,5 -0,5 -0,3 -0,1 0,0 0,05 × (G1 - 10) 0,1 0,1 0,1 0,1 0,2 0,3 0,4 A / (S + A) - 0,2 0,1 0,1 0,2 0,2 0,3 Outer contour shape in relation to the straight line L4 - Within Within Within Within Within Within S1 / S 0,2 0,2 0,2 0,2 0,2 0,2 0,2 G2 / G1 0,4 0,4 0,4 0,4 0,4 0,4 0,4 Elongation at break (top side WF) % 350 350 350 350 350 350 350 Elastic modulus (top side WF) MPa 3,5 3,5 3,5 3,5 3,5 3,5 3,5 Modulus of elasticity (bottom WF) MPa 13,0 13,0 13,0 13,0 13,0 13,0 13,0 S3 / S2 0,250 0,250 0,250 0,250 0,250 0,250 0,250 G3 mm 5,5 5,5 5,5 5,5 5,5 5,5 5,5 G4 mm - 8,0 8,0 8,0 8,0 8,0 8,0 Elongation at break (side) % 400 400 400 400 400 400 400 Elastic modulus (side) MPa 2,0 2,0 2,0 2,0 2,0 2,0 2,0 Elastic modulus (cr) % 350 350 350 350 350 350 350 Presence / absence of the reinforcing layer made of organic fibers Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Presence / absence of the steel reinforcement layer Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Amount of tire weight reduction kg 0 2 1 0,5 1,5 1,2 2 resistance index 100 80 90 90 95 100 98 [Table 1-II] Example 6 Example 7 Example 8 Example 9 Presence / absence of the Available Available Available Available Advanced section G1 mm 16 16 16 16 0,10 × (G1 - 17) -0,1 -0,1 -0,1 -0,1 0,05 × (G1 - 10) 0,3 0,3 0,3 0,3 A / (S + A) 0,2 0,2 0,2 0,2 Outer contour shape in relation to the straight line L4 Outside Outside Outside Outside S1 / S 0,2 0,25 0,4 0,5 G2 / G1 0,4 0,7 0,7 0,7 Elongation at break (top side WF) % 350 350 350 350 Elastic modulus (top side WF) MPa 3,5 3,5 3,5 3,5 Modulus of elasticity (bottom WF) MPa 13,0 13,0 13,0 13,0 S3 / S2 0,250 0,250 0,250 0,250 G3 mm 5,5 5,5 5,5 5,5 G4 mm 8,0 8,0 8,0 8,0 Elongation at break (side) % 400 400 400 400 Elastic modulus (side) MPa 2,0 2,0 2,0 2,0 Elastic modulus (cr) % 350 350 350 350 Presence / absence of the reinforcing layer made of organic fibers Unavailable Unavailable Unavailable Unavailable Presence / absence of the steel reinforcement layer Unavailable Unavailable Unavailable Unavailable Amount of tire weight reduction kg 1,2 1,2 1,2 1,2 resistance index 104 105 107 106 [Table 2] Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Presence / absence of the deepening section Unavailable Available Available Available Available Available Available Available G1 mm 16 16 16 16 16 16 16 16 0,10 × (G1 - 17) -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 0,05 × (G1 - 10) 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 A / (S + A) 0,2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 Outer contour shape in relation to the straight line L4 Outside Outside Outside Outside Outside Outside Outside Outside S1 / S 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 G2 / G1 0,55 0,9 0,7 0,7 0,7 0,7 0,7 0,7 Elongation at break (top side WF) % 350 350 500 500 500 500 500 500 Elastic modulus (top side WF) MPa 3,5 3,5 3,5 4,0 5,5 8,0 5,5 5,5 Modulus of elasticity (bottom WF) MPa 13,0 13,0 13,0 14,0 14,0 14,0 17,0 20,0 S3 / S2 0,250 0,250 0,250 0,250 0,250 0,250 0,250 0,250 G3 mm 5,5 5,5 5,5 5,5 5,5 5,5 5,5 5,5 G4 mm 8,0 8,0 8,0 8,0 8,0 8,0 8,0 8,0 Elongation at break (side) % 400 400 400 400 400 400 400 400 Elastic modulus (side) MPa 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 Elastic modulus (cr) % 350 350 350 350 350 350 350 350 Presence / absence of the reinforcing layer made of organic fibers Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Presence / absence of the steel reinforcement layer Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Amount of tire weight reduction kg 1,2 1,2 1,2 1,2 1,2 1,2 1,2 1,2 resistance index 105 106 109 111 112 111 114 113 [Table 3] Example 18 Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Presence / absence of the deepening section Available Available Available Available Available Available Available Available Available G1 mm 16 16 16 16 16 16 16 16 16 0,10 × (G1 - 17) -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 0,05 × (G1 - 10) 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 A / (S + A) 0,2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 Outer contour shape in relation to the straight line L4 Outside Outside Outside Outside Outside Outside Outside Outside Outside S1 / S 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 G2 / G1 0,7 0,7 0,7 0,7 0,7 0,7 0,7 0,7 0,7 Elongation at break (top side WF) % 500 500 500 500 500 500 500 500 500 Elastic modulus (top side WF) MPa 5,5 5,5 5,5 5,5 5,5 5,5 5,5 5,5 5,5 Modulus of elasticity (bottom WF) MPa 17,0 17,0 17,0 17,0 17,0 17,0 17,0 17,0 17,0 S3 / S2 0,30 0,50 0,80 0,50 0,50 0,50 0,50 0,50 0,50 G3 mm 5,5 5,5 5,5 7,0 9,0 14,0 9,0 9,0 9,0 G4 mm 8,0 8,0 8,0 8,0 8,0 8,0 22,0 28,0 35,0 Elongation at break (side) % 400 400 400 400 400 400 400 400 400 Elastic modulus MPa (side) 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 Elastic modulus (cr) % 350 350 350 350 350 350 350 350 350 Presence / absence of the reinforcing layer made of organic fibers Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Presence / absence of the steel reinforcement layer Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Amount Tire weight kg 1,2 1,2 1,2 1,2 1,2 1,2 1,2 1,2 1,2 reduction Resistance index 115 117 116 118 119 118 120 121 120 [Table 4] Example 27 Example 28 Example 29 Example 30 Example 31 Example 32 Example 33 Presence / absence of the deepening section Available Available Available Available Available Available Available G1 mm 16 16 16 16 16 16 16 0,10 × (G1 - 17) -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 -0,1 0,05 × (G1 - 10) 0,3 0,3 0,3 0,3 0,3 0,3 0,3 A / (S + A) 0,2 0,2 0,2 0,2 0,2 0,2 0,2 Outer contour shape in relation to the straight line L4 Outside Outside Outside Outside Outside Outside Outside S1 / S 0,4 0,4 0,4 0,4 0,4 0,4 0,4 G2 / G1 0,7 0,7 0,7 0,7 0,7 0,7 0,7 Elongation at break (top side WF) % 500 500 500 500 500 500 500 Elastic modulus (top side WF) MPa 5,5 5,5 5,5 5,5 5,5 5,5 5,5 Modulus of elasticity (bottom WF) MPa 17,0 17,0 17,0 17,0 17,0 17,0 17,0 S3 / S2 0,50 0,50 0,50 0,50 0,50 0,50 0,50 G3 mm 9,0 9,0 9,0 9,0 9,0 9,0 9,0 G4 mm 28,0 28,0 28,0 28,0 28,0 28,0 28,0 Elongation at break (side) % 550 550 550 550 550 550 550 Elastic modulus (side) MPa 2,0 2,5 4,0 5,5 4,0 4,0 4,0 Elastic modulus (cr) % 350 350 350 350 500 500 500 Presence / absence of the reinforcing layer made of organic fibers Unavailable Unavailable Unavailable Unavailable Unavailable Available Available Presence / absence of the steel reinforcement layer Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Available Amount of tire weight reduction kg 1,2 1,2 1,2 1,2 1,2 1,2 1,2 resistance index 123 124 125 124 125 126 127

[0055] As can be seen from Tables 1 to 4, in each of Examples 1 to 33, the tire weight was successfully reduced while maintaining favorable durability. In contrast, in Comparative Example 1, the durability was deteriorated even though the tire weight was reduced by providing the recessed portion. List of reference symbols 1 tread section 2 side wall section 3 bead section 4 carcass layers 4a Body section 4b folded back section 5 Bead core 6 bead fillers 6a upper bead filler 6b lower bead filler 7 belt layer 11 Tread rubber layer 12 side rubber layer 13 Rim cushion rubber layer 14 Crack suppression rubber layer 20 Advanced Section 21 Reinforcing layer made of steel 22 Reinforcing layer made of organic fibers P Position with maximum tire width CL Tire Equator QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 5390392 B

[0003]

Claims

[1] Pneumatic tyres comprising: a tread portion extending in a tire circumferential direction and having a ring shape; a pair of sidewall portions disposed on both sides of the tread portion; a pair of bead portions each disposed on an inner side of the sidewall portions in a tire radial direction; a bead core disposed at each bead portion; a bead filler disposed on an outer side of the bead core in the tire radial direction; and at least one carcass layer disposed between the pair of bead portions, wherein the carcass layer comprises a body portion folded from an inner side of the tire to an outer side of the tire around the bead core and the bead filler arranged on each bead portion and located between the pair of bead portions, and a turned-up portion turned up on an outer side of the bead core and the bead filler in the tire width direction, wherein a width between the pair of bead portions in a non-rim mounted state is set to a certain rim width, wherein the pneumatic tire comprises a recess portion which is continuous in the tire circumferential direction in a tire outer surface on an outer side of a turned-up edge of the carcass layer of at least one of the sidewall portions in the tire radial direction and on an inner side of a maximum tire width position in the tire radial direction, the recess portion having a contour, which comprises a multitude of arcs with different radii of curvature in a meridian cross-section, where in the meridian cross-section an area A (unit: mm 2 ) of an area defined by the outer contours of the side wall section and of the bead section and a tangent L1, an area S (unit: mm 2 ) an area defined by the outer contours of the sidewall portion and the bead portion, the body portion, surrounded by a vertical line L2 and a vertical line L3, and a thickness G1 (unit: mm) of the bead filler, measured along the vertical line L2, satisfies the relationship 0.10 × (G1 - 17) ≤ A / (S + A) ≤ 0.05 × (G1 - 10), wherein the tangent L1 is a straight line contacted with the outer contours of the sidewall portion and the bead portion, a contact point P1 is a point at which the tangent L1 and the outer contour of the sidewall portion contact each other, the perpendicular line L2 is a straight line passing through the turned-up edge of the carcass layer and perpendicularly intersecting the body portion, and the perpendicular line L3 is a straight line passing through the contact point P1 and perpendicularly intersecting the body portion. [2] The pneumatic tire according to claim 1, wherein the outer contours of the sidewall portion and the bead portion located between a contact point P2 and a point P3 are preferably located on an outer side of a straight line L4 in the tire width direction, the contact point P2 being a point at which the tangent L1 and the outer contour of the bead portion are in contact with each other, and the point P3 being a point 10 mm away from the contact point P2 on an outer side in the tire radial direction along the outer contours of the sidewall portion and the bead portion, the straight line L4 connecting the contact point P2 and the point P3. [3] A pneumatic tire according to claim 1 or 2, wherein a ratio G2 / G1 of a thickness G2 (unit: mm) of the bead filler measured on a straight line passing through a contact point P2 and perpendicularly intersecting the body portion with respect to the thickness G1 preferably satisfies a relationship of 0.55 ≤ G2 / G1 ≤ 0.90, and a ratio S1 / S of an area S1 (unit: mm 2 ) of an area occupied by the bead filler in the area S satisfies a relationship of 0.25 ≤ S1 / S ≤ 0.50 with respect to the area S, wherein the contact point P2 is a point at which the tangent L1 and the outer contour of the bead portion are in contact with each other. [4] Pneumatic tire according to one of claims 1 to 3, wherein the bead filler has a two-layer structure comprising an upper bead filler and a lower bead filler, and the upper bead filler has an elongation at break of 400% or more. [5] A pneumatic tire according to claim 4, wherein the upper bead filler has a modulus of elasticity at 60 °C of 4.0 MPa or more and 8.0 MPa or less, and the lower bead filler has a modulus of elasticity at 60 °C of 14.0 MPa or more and 20.0 MPa or less. [6] A pneumatic tire according to claim 4 or 5, wherein an area S2 of the upper bead filler and an area S3 of the lower bead filler satisfy the relationship 0.30 ≤ S3 / S2 ≤ 0.

80. [7] A pneumatic tire according to any one of claims 1 to 6, wherein a distance G3 between the turned-up edge and the outer tyre surface, measured on the vertical line L2, is 7.0 mm or more and 14.0 mm or less, and a distance G4 between an outer surface of the recessed portion and the folded edge, measured along an extension line of the folded edge, is 10.0 mm or more and 40.0 mm or less. [8] A pneumatic tire according to any one of claims 1 to 7, wherein a side rubber of the sidewall portion has a breaking elongation of 450% or more and an elastic modulus at 60°C of 2.5 MPa or more and 5.5 MPa or less. [9] A pneumatic tire according to any one of claims 1 to 8, wherein a crack suppression rubber layer is arranged to cover the turned-up edge, and the crack suppression rubber layer has a breaking elongation of 400% or more. [10] A pneumatic tire according to any one of claims 1 to 9, further comprising an organic fiber reinforcing layer on an outer side of the turned-up portion of the carcass layer in the tire width direction, wherein an end portion of the reinforcing layer of organic fibers is located on an outer side in the tire radial direction on the outer side of the turned-up edge in the tire radial direction, an end portion of the reinforcing layer of organic fibers on an inner side in the tire radial direction is located on the inner side of a center of the bead core in the tire radial direction, and an end portion of the organic fiber reinforcing layer on the outer side in the tire radial direction is 6 mm or more away from the recess portion. [11] A pneumatic tire according to any one of claims 1 to 10, further comprising a reinforcing layer made of steel arranged along the outer surfaces of the body portion and the turned-up portion of the carcass layer, wherein an end portion of the steel reinforcement layer on the turned-up portion side is arranged at a position 5 mm to 25 mm away from a position of the turned-up edge on an inner side in the tire radial direction, and an end portion of the steel reinforcing layer on the body portion side is arranged at a position 5 mm to 25 mm away from a position of the turned-up edge on an outer side in the tire radial direction.

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