Method for manufacturing a tyre and green tyre

Abstract

Method for manufacturing a tire and a green tire. The thickness of the inner liner is homogenized. The method for manufacturing a tire comprises a molding step (S1) of forming a green tire (1A), and a vulcanization step (S2) of obtaining a vulcanized tire (1) by pressing the green tire (1A) from the tire inner cavity side using an air bag (32a). In the molding step (S1), the inner liner (9) comprises a base portion (9a) and a pair of thick wall portions (9b) having a thickness greater than the base portion (9a). The green tire (1A) is molded in such a way that the pair of thick wall portions (9b) do not overlap the belt layer (7) in the tire meridian direction.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a tire and a green tire. BACKGROUND

[0002] A green tire having an inner liner layer with air impermeability is described in Patent Document 1. The average thickness Tl of the crown center portion of the inner liner layer, the average thickness T2 of a portion of the local portion from the shoulder portion to the side portion, and the average thickness T3 of the remaining portion of the side portion are constituted by the following formulas (1) and (2).

[0003] T2 = 1.3 x Tl ~ 2.2 x Tl... (1)

[0004] T3 = 0.8 x Tl ~ 1.0 x Tl... (2)

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 7-32813 SUMMARY

[0006] In such a green tire, when vulcanization is performed with an air bag pressed against the inner liner layer, the thickness of the inner liner layer becomes uniform.

[0007] Generally, a belt layer with a large rigidity is arranged in the tread portion of a tire. The present inventors have found that, when a green tire is pressed from the inside of the tire cavity by an air bag, the amount of deformation of the air bag differs between a portion where the belt layer is arranged and a portion where the belt layer is not arranged. The invention of the above-described Patent Document 1 does not take such a belt layer into consideration, and there is room for improvement in terms of uniformizing the thickness of the inner liner layer.

[0008] The present application has been made in view of the above actual circumstances, and it is an object thereof to provide a manufacturing method of a tire and a green tire that can uniformize the thickness of an inner liner layer.

[0009] The present application provides a manufacturing method of a tire, in which the manufacturing method of a tire includes a molding step in which a green tire is molded, the green tire including an inner liner layer and a belt layer, the inner liner layer extending across a pair of bead portions in a ring shape, the belt layer being arranged on the outer side in the tire radial direction of the inner liner layer and in a tread portion, and a vulcanization step in which a vulcanized tire is obtained by pressing the green tire from the inside of the tire cavity with an air bag, the green tire being molded in the molding step in such a manner that the inner liner layer includes a base portion and a pair of thick wall portions having a larger thickness than the base portion, the pair of thick wall portions not overlapping the belt layer in the tire meridian direction.

[0010] In the manufacturing method of a tire of the present application, it is preferable that the pair of thick wall portions of the green tire be located at a pair of shoulder portions of the vulcanized tire.

[0011] In the tire manufacturing method of the present application, preferably, the pair of thick wall portions of the green tire is located radially outward of a position of a maximum width of the vulcanized tire.

[0012] In the tire manufacturing method of the present application, preferably, the inner liner includes a first rubber sheet constituting the base portion and a second rubber sheet adhered to the first rubber sheet, and a bonded portion of the first rubber sheet and the second rubber sheet constitutes the thick wall portion.

[0013] In the tire manufacturing method of the present application, preferably, the first rubber sheet has a thickness of 1.0 mm to 1.5 mm.

[0014] In the tire manufacturing method of the present application, preferably, the second rubber sheet has a thickness of 0.8 mm to 2.0 mm.

[0015] In the tire manufacturing method of the present application, preferably, the second rubber sheet has an overlapping portion in which end portions in the tire circumferential direction overlap each other, and a length of the overlapping portion in the tire circumferential direction is 30 degrees or less around a center of rotation of the green tire.

[0016] In the tire manufacturing method of the present application, preferably, the overlapping portion is located at a position separated from a light point of the green tire by ±10 degrees in the tire circumferential direction.

[0017] The present application provides a green tire before vulcanization, the green tire including: an inner liner extending in a ring shape across a pair of bead portions; and a belt layer disposed radially outward of the inner liner and disposed in a tread portion, the inner liner including a base portion and a pair of thick wall portions having a larger thickness than the base portion, the pair of thick wall portions being disposed so as not to overlap the belt layer in a tire meridian direction.

[0018] In the tire manufacturing method of the present application, in a molding step of forming a green tire, an inner liner includes a base portion and a pair of thick wall portions having a larger thickness than the base portion, and the pair of thick wall portions does not overlap a belt layer in a tire meridian direction. Therefore, for a tire manufactured by the tire manufacturing method of the present application, in a vulcanization step, the pair of thick wall portions is stretched to a greater extent than the base portion by a bladder, and thus the thickness of the inner liner is uniform.

[0019] For the green tire of the present application, an inner liner includes a base portion and a pair of thick wall portions having a larger thickness than the base portion, and the pair of thick wall portions is disposed so as not to overlap a belt layer in a tire meridian direction. When such a green tire is vulcanized by being pressed from an inner cavity side of the tire by a bladder, the pair of thick wall portions is stretched to a greater extent than the base portion. Therefore, for a tire obtained after the green tire of the present application is vulcanized, the thickness of the inner liner is uniform. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a sectional view showing one embodiment of a tire manufactured by the tire manufacturing method of the present application.

[0021] Figure 2 (a), (b) are plan and sectional views of a molding drum used to explain the molding step of the present application.

[0022] Figure 3 is a sectional view of a first molded body used to explain the molding step of the present application.

[0023] Figure 4 is a tire meridian sectional view of a green tire.

[0024] Figure 5 is a sectional view after the green tire is cut in the circumferential direction.

[0025] Figure 6 is a sectional view used to explain the vulcanization step of the present application.

[0026] Figure 7 is a plan view of a molding drum used to explain the molding step of another embodiment of the present application.

[0027] REFERENCE NUMERALS

[0028] 1: vulcanized tire; 1A: green tire; 7: belt layer; 9: inner liner; 9a: base portion; 9b: thick wall portion; 32a: air bag; S1: molding step; S2: vulcanization step. DETAILED DESCRIPTION

[0029] Hereinafter, one embodiment of the present application will be explained with reference to the drawings.

[0030] Figure 1 is a tire meridian sectional view of a tire 1 manufactured by a tire manufacturing method of the present embodiment (hereinafter, sometimes referred to simply as "manufacturing method"). Figure 1 represents a pneumatic tire for a passenger car. In addition, the present application can be used for a manufacturing method of a pneumatic tire for a motorcycle or a heavy load, in addition to a passenger car.

[0031] As shown in Figure 1 , the tire 1 of the present embodiment includes an inner liner 9 extending across a pair of bead portions 4, 4 in a ring shape, a belt layer 7 disposed on the tire radial direction outer side of the inner liner 9 and disposed in the tread portion 2. In addition, the tire 1 includes, for example, a tread rubber 2G, a sidewall rubber 3G, a bead core 5, a carcass 6, a bead apex rubber 8, and the like.

[0032] The tire carcass 6 is formed, for example, from a known tire carcass ply 6A, which includes a main body 6a spanning between the bead cores 5 and a pair of folded-back portions 6b connected to the main body 6a. The tread compound 2G, sidewall compound 3G, bead core 5, and bead triangle compound 8 may, for example, adopt known structures.

[0033] In this embodiment, the belt layer 7 is formed by two belt ply layers 7A and 7B disposed on the inner and outer sides of the tire radial direction. In this embodiment, the tire axial length of the inner belt ply layer 7A is made larger than the tire axial length of the outer belt ply layer 7B. Each belt ply layer 7A and 7B has, for example, steel cords arranged at an angle of 45° to 75° relative to the tire circumference. However, each belt ply layer 7A and 7B is not limited to this arrangement.

[0034] In this embodiment, the inner liner 9 is formed of rubber with excellent air impermeability. The inner liner 9 is disposed, for example, on the inner side of the tire carcass 6 in the tire radial direction, forming the tire inner cavity surface 1b.

[0035] Next, the manufacturing method of tire 1 will be described. The manufacturing method of this embodiment includes the following steps: forming an uncured green tire 1A ( Figure 4 The molding process S1 (shown) and the vulcanization process S2, which vulcanizes the green tire 1A to obtain the vulcanized tire (tire) 1. Here, "unvulcanized" means all forms of vulcanization that have not been fully achieved, and the so-called semi-vulcanized state is included in "unvulcanized".

[0036] The molding process S1 of this embodiment includes the following steps: the first step N1 (where the inner liner 9 is wound around the molding drum 30 to form the first molded body 25). Figure 2 (as shown); and the second step N2 (to form the green body 1A by attaching the belt layer 7 to the first molded body 25). Figure 3 (As shown).

[0037] Figure 2 (a) is a top view of the molding drum 30. Figure 2 (b) is a cross-sectional view of the forming drum 30. For example... Figure 2 (a) and Figure 2 As shown in (b), the forming drum 30 adopts a known structure, for example, a cylindrical winding surface 30a having a winding inner liner 9 and a rotatable support shaft 30b supporting the winding surface 30a.

[0038] In the first step N1, the rubber sheet 10 constituting the inner liner layer 9 is first wound. In this embodiment, the rubber sheet 10 includes a first rubber sheet 11 and a second rubber sheet 12 adhered to the first rubber sheet 11. The second rubber sheet 12 has, for example, a width (axial length of the molding drum 30) w smaller than that of the first rubber sheet 11.

[0039] The first rubber sheet 11 is formed of, for example, a butyl rubber excellent in air impermeability. The second rubber sheet 12 is preferably formed of, for example, a mixed rubber having moderate rubber strength and excellent in resistance to reversion, resistance to crack growth, tear strength, and cord adhesion. In addition, the second rubber sheet 12 can be the same rubber as the first rubber sheet 11.

[0040] In the first step N1 of the present embodiment, first, the first rubber sheet 11 is wound on the winding surface 30a of the molding drum 30. In the present embodiment, the first rubber sheet 11 includes an overlapping portion 11s in which the winding start end portion 11a and the winding terminal end portion 11b overlap in the radial direction of the molding drum 30. Thus, in the present embodiment, the first rubber sheet 11 is formed in a cylindrical shape. The winding start end portion 11a and the winding terminal end portion 11b form end portions in the tire circumferential direction.

[0041] Next, the second rubber sheet 12 is wound on the first rubber sheet 11. In the present embodiment, two second rubber sheets 12 are used. In the present embodiment, each of the second rubber sheets 12 is wound in a manner separated in the axial direction of the molding drum 30. Thus, the inner liner 9 of the present embodiment includes a base portion 9a sandwiched between the second rubber sheets 12, 12, formed of only the first rubber sheet 11, and a pair of thick wall portions 9b, 9b formed as the bonded portions 13 of the first rubber sheet 11 and the second rubber sheets 12. The inner liner 9 of the present embodiment includes a pair of outer side portions 9c, 9c formed of only the first rubber sheet 11 on the outer side of the second rubber sheets 12 in the axial direction of the molding drum 30. The outer side portion 9c has, for example, the same thickness as the base portion 9a. In addition, the outer side portion 9c is not limited to this configuration.

[0042] The second rubber sheet 12 includes an overlapping portion 12s in which the winding start end portion 12a and the winding terminal end portion 12b overlap in the radial direction of the molding drum 30. The winding start end portion 12a and the winding terminal end portion 12b form end portions in the tire circumferential direction. Further, preferably, the overlapping portion 11s of the first rubber sheet 11 and the overlapping portion 12s of the second rubber sheet 12 are formed in a manner offset in the circumferential direction of the molding drum 30. Thus, it is possible to suppress excessive increase in the thickness of the inner liner 9 before vulcanization at the overlapping portion 12s, and thus it is possible to uniformize the thickness T of the inner liner 9 in the vulcanized tire 1. Figure 1

[0043] Although not particularly limited, the angle a1 of the molding drum 30 in the circumferential direction between the overlapping portion 11s of the first rubber sheet 11 and the overlapping portion 12s of the second rubber sheet 12 is preferably, for example, 30 degrees or more, more preferably 60 degrees or more, and further preferably 90 degrees or more.

[0044] ​The thickness t1 of the first rubber sheet 11 is 1.0 mm to 1.5 mm. This first rubber sheet 11 reduces the mass of the tire 1 while suppressing the permeation of the carcass 6, known as the so-called open cord, thus helping to maintain the air impermeability of the tire 1. The tire 1 with its smaller mass exhibits excellent rolling resistance performance. The thickness t2 of the second rubber sheet 12 is 1.8 mm to 2.0 mm. This second rubber sheet 12 ensures the thickness (t1+t2) of the thick-walled portion 9b, helping to maintain the air impermeability of the inner liner 9, which is stretched through vulcanization. Furthermore, this thickness t2 of the second rubber sheet 12 prevents air from accumulating near the overlapping portion 12s.

[0045] Although not specifically limited, the width w of the second rubber sheet 12 is preferably the tire section height of the vulcanized tire 1. Figure 1 The width w of the second rubber sheet 12 is preferably 5% or more, more preferably 7% or more, and even more preferably 10% or more of the tire section height H of the vulcanized tire 1.

[0046] Next, in the first step N1 of this embodiment, the carcass ply 6A is wound around the outside of the inner liner 9. Furthermore, in the first step N1, for example, sidewall rubber 3G, bead triangle rubber 8, and bead core 5 are further disposed on the outside of the carcass ply 6A. Figure 3 (As shown). Thus, a cylindrical first molded body 25 is formed in the first step N1. In this embodiment, the first molded body 25 is expanded into a ring shape by a molding apparatus 31 with a known structure.

[0047] Figure 3 This is a cross-sectional view illustrating the first molded body 25 in the second step N2. (Example) Figure 3 As shown, in the second step N2 of this embodiment, belt ply layers 7A and 7B are adhered to the first molded body 25, which has expanded into a ring shape. In this embodiment, the belt ply layers 7A and 7B are arranged in a manner that does not overlap with a pair of thick-walled portions 9b, 9b along the tire meridian direction F. In this specification, as... Figure 4 As indicated by the arrow, the "tire radial direction F" is along the direction of the main body portion 6a of the tire carcass ply 6A. Furthermore, "non-overlapping" means that the belt ply layers 7A and 7B do not overlap with the thick-walled portion 9b in a direction orthogonal to the tire radial direction F.

[0048] Additionally, in the second step N2, for example, a tread compound 2G with a known structure is adhered to the outer side of the belt ply layers 7A and 7B. Figure 4 (As shown). In this way, a cylindrical green embryo 1A is formed.

[0049] Figure 4is a meridian cross-sectional view of the tire taken through the center of rotation (omitted from the drawing) of the green tire 1A formed in the molding step S1. As shown in the figure, in the green tire 1A, each thick wall portion 9b is preferably located in a shoulder portion Sh of the vulcanized tire 1 (omitted from the drawing). Figure 4 Figure 1 As shown in the figure, in the green tire 1A, each thick wall portion 9b is preferably located in a shoulder portion Sh of the vulcanized tire 1 (omitted from the drawing). The shoulder portion Sh is a portion in which the bladder 32a deforms the most when the bladder 32a is pressed from the tire inner cavity side in the vulcanization step S2 (omitted from the drawing). Therefore, by arranging the thick wall portion 9b in the shoulder portion Sh, the thickness T of the inner liner layer 9 is further homogenized. Figure 6

[0050] In the green tire 1A, it is preferable that each thick wall portion 9b be located on the tire radial outer side of a tire maximum width position M (omitted from the drawing) of the tire 1. Generally, at the tire radial inner side of the tire maximum width position M, the deformation of the bladder 32a is suppressed. Thus, the above-mentioned effects can be more effectively exerted. Figure 1

[0051] The tire maximum width position M is a position at which the main portion 6a of the carcass ply 6A protrudes the most to the tire axial outer side in the tire 1 in a standard state. The "standard state" refers to a state in which the tire 1 is mounted to a standard rim (not shown) and filled with a standard internal pressure in a no-load state.

[0052] The "standard rim" refers to a rim determined in accordance with the tire in a specification system including the specification to which the tire 1 adheres, for example, a standard rim if JATMA, a "Design Rim" if TRA, and a "Measuring Rim" if ETRTO.

[0053] The "standard internal pressure" refers to an air pressure determined in accordance with each specification in a specification system including the specification to which the tire 1 adheres, for example, the highest air pressure if JATMA, the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" if TRA, and the "INFLATION PRESSURE" if ETRTO.

[0054] ​​​In the green tire 1A, the length La in the tire meridian direction F between the inner end 9e of the thick wall portion 9b in the tire axial direction and the outer end 7e of the belt layer 7 (the inner belt layer 7A) is preferably 10 mm or less, more preferably 8 mm or less, and further preferably 5 mm or less. The length La can be 0 mm or more. Thus, at the shoulder portion Sh where the air bag 32a is largely deformed, the thickness T of the inner liner 9 after vulcanization can be inhibited from being excessively reduced, the uniformity of the thickness T can be ensured, and the air impermeability can be maintained.

[0055] Figure 5 is a cross-sectional view schematically showing a state after the green tire 1A is cut in the circumferential direction on the second rubber sheet 12. As Figure 5 indicated, in the green tire 1A of the present embodiment, the length LI in the tire circumferential direction of the overlapping portion 12s of the second rubber sheet 12 is preferably an angle θl of 30 degrees or less around the center of rotation c of the green tire 1A, more preferably an angle θl of 27 degrees or less, and further preferably an angle θl of 25 degrees or less. Thus, since the circumferential length LI of the overlapping portion 12s having a large thickness is maintained small, the deterioration of the circumferential mass balance of the tire 1 can be inhibited. In addition, if the length LI in the tire circumferential direction of the overlapping portion 12s is small, the second rubber sheet 12 can possibly be separated in the tire circumferential direction. Therefore, the length LI in the tire circumferential direction of the overlapping portion 12s of the second rubber sheet 12 is preferably an angle θl of 5 degrees or more around the center of rotation c of the green tire 1A, more preferably an angle θl of 7 degrees or more, and further preferably an angle θl of 10 degrees or more. The tire 1 having a poor mass balance can adversely affect, for example, the ride comfort performance and the running stability performance.

[0056] According to the same viewpoint, the length L2 in the tire circumferential direction of the overlapping portion 11s of the first rubber sheet 11 is preferably an angle θ2 of 5 degrees or more around the center of rotation c of the green tire 1A, more preferably an angle θ2 of 7 degrees or more, and further preferably an angle θ2 of 10 degrees or more. In addition, the length L2 in the tire circumferential direction of the overlapping portion 11s is preferably an angle θ2 of 30 degrees or less around the center of rotation c of the green tire 1A, more preferably an angle θ2 of 27 degrees or less, and further preferably an angle θ2 of 25 degrees or less. In Figure 5 In the drawing, the two overlapping portions 11s and 12s are colored for convenience of explanation.

[0057] The overlapping portion 12s of the second rubber sheet 12 is preferably located at a position separated by ±10 degrees in the tire circumferential direction (around the center of rotation c of the green tire 1A) from a light point (not shown) of the green tire 1A. Thus, the mass balance is further improved. The above "light point" refers to a position having the lightest weight in the circumferential direction of the green tire 1A.

[0058] Figure 6 is a cross-sectional view schematically showing a state after the green tire 1A is cut in the circumferential direction on the second rubber sheet 12. As Figure 6As shown, in the vulcanization step S2 of the present embodiment, a vulcanization mold 32 having a publicly known structure of a bladder 32a is used. The green tire 1A is formed into a vulcanized tire 1 by being pressed from the inside of the tire cavity by the bladder 32a to be vulcanized. Through such a vulcanization step S2, a tire 1 including the inner liner layer 9 having a uniform thickness T is formed. Figure 1

[0059] Figure 7 is a plan view showing a manufacturing method of the first step N1 of another embodiment. The same reference numerals are assigned to the same structures as those of the present embodiment, and the description thereof is omitted. As shown, in the first step N1 of the present embodiment, the first rubber sheet 11 is wound on the second rubber sheet 12, which is wound on the winding face 30a with a smaller width. Even in such a first step N1, the thickness T of the inner liner layer 9 after vulcanization can be made uniform. Figure 7

[0060] The above describes a particularly preferred embodiment of the present application in detail, but the present application is not limited to the illustrated embodiment, and can be modified into various modes to be implemented. For example, one rubber sheet (omitted from illustration) having a base portion 9a and a pair of thick wall portions 9b, 9b is formed by extrusion molding, and the rubber sheet is wound on the molding drum 30 to mold the inner liner layer 9 of the green tire 1A.

[0061]

EXAMPLES

[0062] A green tire having the basic configuration of Figure 4 was formed, and a vulcanized tire (tire) was manufactured using a vulcanization device of Figure 6 . Further, the uniformity performance, air non-permeation performance, and mass balance performance of the tire were tested. The test methods and general specifications are shown below.

[0063] Tire size: 265 / 75R16

[0064] In each example, the thick wall portion is located on the tire radial direction outer side from the tire maximum width position.

[0065] The width of the first rubber sheet and the width of the second rubber sheet are the same in each example.

[0066] "-" of "La" indicates that the thick wall portion overlaps the belt in the tire meridian direction.

[0067] <Uniformity Performance>

[0068] A tester measured the thickness of the inner liner layer at 50 mm intervals in the tire circumferential direction and the tire axial direction, and calculated the average deviation thereof. The result is expressed using an index in which the average deviation of Comparative Example 1 is set to 100. The smaller the value, the better the uniformity performance.

[0069] ​​<Air non-permeation performance>

[0070] A tire with a standard rim installed was left to stand for 60 days with an internal pressure of 250 kPa. Then, the internal pressure at that time was measured, and the internal pressure drop rate was calculated. The result is expressed using an index in which the internal pressure drop rate of Comparative Example 1 is taken as 100. The smaller the value, the better the air non-permeation performance.

[0071] <Mass balance performance>

[0072] A known balancer was used to measure the dynamic unbalance amount of each tire. The result is expressed using an index in which the dynamic unbalance amount of Comparative Example 1 is taken as 100. The smaller the value, the better the mass balance performance.

[0073] [Table 1]

[0074]

[0075] It was confirmed that the manufacturing method of the examples was superior in uniformity performance to the manufacturing method of the comparative examples. In addition, it was confirmed that the tire of the embodiment was superior in air non-permeation performance because the inner liner layer had a minimum thickness, and the tire mass was maintained small. Furthermore, it was confirmed that the smaller the length (θ1) of the overlap portion, the more superior the uniformity performance. In addition, the tire of Example 4 had air remaining in the overlap portion to an extent that did not adversely affect the quality of the tire.

Claims

1. A method for manufacturing a tire, the method comprising the following steps: A forming process is performed in which a green tire is formed, the green tire comprising an inner liner and a belt layer, the inner liner extending annularly across a pair of bead portions, and the belt layer disposed radially outside the inner liner and on the tread portion; and The vulcanization process involves using an airbag to press the green tire from the inner cavity side of the tire to obtain a vulcanized tire. In the molding process, the tire is formed in such a manner that the inner liner includes a base and a pair of thick-walled portions with a thickness greater than the base, the pair of thick-walled portions not overlapping the belt layer along the tire's radial direction. The rubber sheet constituting the inner liner includes a first rubber sheet and a second rubber sheet adhered to the radially outer side of the tire of the first rubber sheet. The first rubber sheet constitutes the base, and the bonding portion between the first rubber sheet and the second rubber sheet constitutes the thick-walled portion.

2. The tire manufacturing method according to claim 1, wherein, The pair of thick-walled portions of the green tire are located at the pair of shoulders of the vulcanized tire.

3. The method for manufacturing a tire according to claim 1 or 2, wherein, The pair of thick-walled portions of the green tire are located radially outward from the position of the maximum tire width of the vulcanized tire.

4. The method for manufacturing a tire according to claim 1 or 2, wherein, The thickness of the first rubber sheet is 1.0 mm to 1.5 mm.

5. The method for manufacturing a tire according to claim 1 or 2, wherein, The thickness of the second rubber sheet is 0.8mm to 2.0mm.

6. The method for manufacturing a tire according to claim 1 or 2, wherein, The second rubber sheet has an overlapping portion formed by the circumferential ends of the tire overlapping each other. The circumferential length of the overlapping portion of the tire is less than 30 degrees around the center of rotation of the green tire.

7. The method for manufacturing a tire according to claim 6, wherein, The overlapping portion is located at a position ±10 degrees away from the light point of the green tire along the tire circumference.

8. A type of raw embryo, which is a raw embryo before vulcanization, wherein, The green tire includes: an inner liner that extends in a ring shape between a pair of bead portions; And a belt layer, which is disposed radially outside the inner liner and on the tread portion. The inner liner includes a base and a pair of thick-walled portions with a thickness greater than the base, the pair of thick-walled portions being configured in a manner that does not overlap with the belt layer along the tire radial direction. The rubber sheet constituting the inner liner includes a first rubber sheet and a second rubber sheet adhered to the radially outer side of the tire of the first rubber sheet. The first rubber sheet constitutes the base, and the bonding portion between the first rubber sheet and the second rubber sheet constitutes the thick-walled portion.

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