JP2006231564A - Manufacturing method of pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a pneumatic tire capable of preventing the unevenness corresponding to a carcass cord from appearing on an inner liner after a green tire is vulcanized and molded. <P>SOLUTION: The manufacturing method of the pneumatic tire 10 comprising a bead core 12, a carcass 14, a tread rubber 18, a side rubber 22 and the inner liner 28 comprises a process for arranging a preliminarily vulcanized rubber sheet 30 to the region ranging from the position corresponding at least to the tread end 20A of the pneumatic tire 10 to the position corresponding to the maximum width part 24A of the pneumatic tire 10 between the carcass 14 and the inner liner 28 before a process for vulcanizing molding the green tire in a stage that the pneumatic tire 10 is the green tire. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a method for manufacturing a pneumatic tire, and more particularly, to a method for manufacturing a pneumatic tire in which unevenness corresponding to a carcass cord appears on the inner liner during vulcanization molding of a raw tire (cord appearance phenomenon). About.

  Conventionally, when a carcass sheet is wound around a molding drum to form a carcass layer, a rubber sheet that has been irradiated with an electron beam in advance from the shoulder portion to the side portion on the inner surface of the tire of the carcass layer is arranged over the entire circumference of the tire. A method for manufacturing a pneumatic tire is known (for example, see Patent Document 1).

According to the example described in Patent Document 1, since the rubber sheet irradiated with the electron beam in advance is hardened more than the rubber of the carcass layer, at the site where the rubber sheet is disposed at the time of vulcanization molding of the raw tire It is said that the disturbance of the code arrangement can be prevented by suppressing the movement of the carcass code.
JP-A-4-175149

  However, in the example described in Patent Document 1, irregularities corresponding to the carcass cord appear in the inner liner in a process of forming a pneumatic tire as a product tire by vulcanizing a raw tire (cord appearance phenomenon). There is a problem that no consideration is given to preventing the above.

  In other words, in the conventional pneumatic tire manufacturing method, when the raw tire is expanded with the bladder during vulcanization molding of the raw tire, the inner liner has irregularities corresponding to the carcass cord due to insufficient rubber gauge between the carcass and the inner liner. May appear.

  Furthermore, in the conventional pneumatic tire manufacturing method, in the process of vulcanizing and molding a green tire, the carcass is directly expanded by the bladder only through the relatively thin inner liner, so that the expansion force applied to the carcass is not sufficient. It becomes uniform.

  Accordingly, the arrangement of the carcass cords may be disturbed, or the carcass may be locally deformed, and this may cause irregularities corresponding to the carcass cords to appear on the inner liner.

  The present invention has been made in view of the above circumstances, and an object thereof is to produce a pneumatic tire capable of preventing irregularities corresponding to a carcass cord from appearing on an inner liner after vulcanization molding of a raw tire. It is to provide a method.

  In order to solve the above-described problem, the invention according to claim 1 includes a pair of left and right bead cores extending along the tire circumferential direction, a toroidal shape between the pair of left and right bead cores, and portions on both ends in the tire width direction. A carcass formed of at least one layer of a carcass ply in which a plurality of parallelly arranged carcass cords are covered with rubber, and a tread portion provided on the outer side in the tire radial direction of the carcass. And a pair of left and right side rubbers that are provided on the outer side in the tire axial direction of the carcass to form sidewall portions, and an inner liner that is provided on the inner side of the tire of the carcass. In the manufacturing method, the green tire is vulcanized when the pneumatic tire is a green tire. Before that, a vulcanized rubber sheet is disposed between the carcass and the inner liner in a region extending from at least a position corresponding to the tread end of the pneumatic tire to a position corresponding to the tire maximum width portion. Including a process.

  Next, the operation of the invention described in claim 1 will be described.

  As described in claim 1, before the step of vulcanizing and forming the green tire when the pneumatic tire is a green tire, it corresponds to at least the tread end of the pneumatic tire between the carcass and the inner liner. Placing a pre-vulcanized rubber sheet in the area from the position to the position corresponding to the tire's maximum width part ensures a sufficient rubber gauge between the carcass and the inner liner during vulcanization molding of the raw tire. Therefore, it becomes possible to prevent the unevenness corresponding to the carcass cord from appearing on the inner liner.

  In addition, since the rubber sheet is disposed between the carcass and the inner liner, the carcass is expanded by the bladder through the inner liner and the rubber sheet in the process of vulcanizing and forming the green tire. The expansion force applied to is equalized.

  As a result, it is possible to prevent the arrangement of the carcass cord from being disturbed or the carcass from being locally deformed, and this also shows that irregularities corresponding to the carcass cord appear on the inner liner. It becomes possible to prevent.

  Further, by vulcanizing the rubber sheet in advance as described above, the hardness of the rubber sheet can be increased in advance before the vulcanization molding step of the raw tire, thereby vulcanizing and molding the raw tire. In the process, the flow of the rubber sheet can be suppressed.

  Thereby, the unevenness | corrugation corresponding to a carcass cord appears reliably on an inner liner.

  The invention according to claim 2 is the method for producing a pneumatic tire according to claim 1, wherein a rayon cord is used for the carcass cord, and the rubber sheet vulcanized in advance is 0.3 mm to 0 mm. .8 mm thickness is used.

  Next, the operation of the second aspect of the invention will be described.

  According to the invention described in claim 2, even when a rayon cord is used for the carcass cord, by using a rubber sheet having a thickness of 0.3 mm to 0.8 mm as a pre-cured rubber sheet, Since a sufficient rubber gauge between the inner liner and the inner liner can be secured, it is possible to prevent irregularities corresponding to the carcass cord from appearing on the inner liner.

  If the thickness of the rubber sheet is less than 0.3 mm, the effect of suppressing the appearance of irregularities corresponding to the carcass cord on the inner liner may not be exhibited.

  Moreover, if the thickness of the rubber sheet is greater than 0.8 mm, the rubber gauge between the carcass and the inner liner becomes excessive, which may affect the performance of a pneumatic tire as a product tire.

  The invention according to claim 3 is the method for producing a pneumatic tire according to claim 1 or claim 2, wherein the rubber sheet vulcanized in advance has a JIS hardness of 60 ° to 80 °. It is characterized by using.

  Next, the operation of the third aspect of the invention will be described.

  As described in claim 3, when a vulcanized rubber sheet having a JIS hardness of 60 ° to 80 ° is used, the flow of the rubber sheet can be suppressed in the process of vulcanizing and molding the raw tire. Therefore, it is possible to effectively exert the effect of suppressing the unevenness corresponding to the carcass cord from appearing on the inner liner, and at the same time, the rubber sheet can ensure flexibility, so that It is possible to prevent the efficiency from decreasing.

  If the JIS hardness of the rubber sheet is lower than 60 °, the flow of the rubber sheet cannot be suppressed in the process of vulcanizing the green tire, and the unevenness corresponding to the carcass cord appears on the inner liner. There is a possibility that the effect is not exhibited.

  On the other hand, if the JIS hardness of the rubber sheet is higher than 80 °, the rubber sheet becomes too hard and the working efficiency may be lowered.

  The invention according to claim 4 is the method for producing a pneumatic tire according to any one of claims 1 to 3, wherein the raw tire has a tire maximum diameter of 1% to 1% when vulcanized. The pneumatic tire is formed by inflating 3%.

  Next, the operation of the fourth aspect of the invention will be described.

  As described in claim 4, when a pneumatic tire is formed by inflating a raw tire to a maximum tire diameter of 1% to 3% during vulcanization molding, a target tire rigidity can be obtained. In addition, the effect of suppressing the appearance of irregularities corresponding to the carcass cord on the inner liner can be effectively exhibited.

  At this time, if the expansion of the raw tire is smaller than 1%, the desired rigidity cannot be obtained, and if the expansion of the raw tire is larger than 3%, irregularities corresponding to the carcass cord may appear on the inner liner. Increases nature.

  The invention according to claim 5 is the method of manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein the pneumatic tire is mounted on a standard rim and filled with a specified internal pressure. The length measured along the tire axial direction from the tire equatorial plane to the maximum tire width measured in the no-load state is the tire half-width SW, and from the bead base line to the outermost position in the tire radial direction along the tire radial direction. Is 15% of the tire cross-section height SH from the bead base line from a position of 60% of the tire half-width SW from the tire equatorial plane in the pneumatic tire. The rubber sheet is arranged in a region reaching the position.

  Next, the operation of the fifth aspect of the invention will be described.

  The length measured along the tire axial direction from the tire equatorial plane to the tire maximum width portion measured in an unloaded state in which a pneumatic tire is mounted on a standard rim and filled with a specified internal pressure as described in claim 5 The tire half-width SW is greater than the tire equatorial plane in a pneumatic tire when the length from the bead base line to the tire radial direction outermost position is the tire cross-sectional height SH. The region from the position of 60% of the tire to the position of 15% of the tire cross-section height SH from the bead base line is a part with a small curvature radius compared to other parts in the vulcanization molding process, This is a part where the carcass cord easily moves to the inside of the tire.

  Therefore, by arranging the rubber sheet in this region, it is possible to reliably suppress the appearance of irregularities corresponding to the carcass cord on the inner liner.

  As described above in detail, according to the method for manufacturing a pneumatic tire of the present invention, a rubber gauge between the carcass and the inner liner can be sufficiently secured and added to the carcass in the process of vulcanizing and molding the raw tire. By making the expansion force uniform, it is possible to prevent the arrangement of the carcass cord from being disturbed or the carcass from being locally deformed, so that the inner liner has irregularities corresponding to the carcass cord. It can be prevented from appearing.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the members, configurations, arrangements, and the like described below do not limit the present invention, and it is needless to say that various modifications can be made in accordance with the spirit of the present invention.

  First, the configuration of the pneumatic tire 10 according to the present embodiment will be described.

  The pneumatic tire 10 according to the present embodiment is preferably used as a radial tire for a passenger car, for example.

  The pneumatic tire 10 according to the present embodiment is provided with a pair of left and right bead cores 12 extending along the tire circumferential direction, and a carcass 14 is provided between the pair of left and right bead cores 12 so as to straddle a toroidal shape. .

  The carcass 14 includes at least one layer (in this example, one layer) of a carcass ply (all not shown) in which a plurality of parallel carcass cords are covered with rubber. Each bead core 12 is locked so as to be wound up from the inside to the outside.

  A carcass cord (not shown) provided in the carcass 14 is arranged at an angle of 0 ° to 2 ° with respect to the tire equatorial plane CL in the tread portion 20. As a carcass cord, a rayon cord is used as an example.

  And the bead filler 16 which makes a cross-sectional triangle shape is arrange | positioned at the tire radial direction outer side of a pair of right and left bead core 12, respectively.

  A tread rubber 18 is provided on the outer side of the carcass 14 in the tire radial direction, whereby a tread portion 20 is configured in the pneumatic tire 10 of this example.

  Further, a side rubber 22 is provided on the outer side in the tire axial direction of the carcass 14, and thereby, a sidewall portion 24 is configured in the pneumatic tire 10 of this example.

  Between the carcass 14 and the tread rubber 18, a belt 26 composed of at least one layer (in this example, two layers) of belt plies is disposed, and an inner liner 28 is provided inside the tire of the carcass 14. It has been.

  In the pneumatic tire 10 of this example, at least in the region between the carcass 14 and the inner liner 28 from the tread end 20A to the tire maximum width portion 24A, the raw tire 10 is a raw tire when it is a raw tire. A rubber sheet 30 vulcanized in advance before the step of vulcanizing and molding the tire is disposed.

  As will be described in detail later, the rubber sheet 30 is provided in order to prevent irregularities corresponding to a carcass cord (not shown) from appearing on the inner liner 28 during vulcanization molding of a raw tire.

  Here, the tread end 20A means that the pneumatic tire 10 is attached to a standard rim defined in JATMA YEAR BOOK (2004 edition, Japan Automobile Tire Association Standard), and in the applicable size and ply rating in JATMA YEAR BOOK. Fills 100% of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table) as the internal pressure, and indicates the outermost ground contact portion in the tire width direction when the maximum load capacity is loaded. In addition, when TRA standard and ETRTO standard are applied in a use place or a manufacturing place, it follows each standard.

  And in this embodiment, as an example, the rubber sheet 30 is arrange | positioned at the following area | region.

  That is, the tire maximum width portion 24A (when the rim guard 32 is provided, the portion excluding the rim guard 32) is measured from the tire equatorial plane CL which is measured in a no-load state in which the pneumatic tire 10 is mounted on the standard rim and filled with the specified internal pressure. The length measured along the tire axial direction to the tire maximum width portion) is defined as the tire half-width SW, and the length from the bead base line BL to the outermost position in the tire radial direction along the tire radial direction is defined as the tire cross-section height SH. In this case, the rubber sheet 30 is disposed in a region from a position of 60% of the tire half-width SW to the position of 15% of the tire cross-section height SH from the bead base line BL to the tire equatorial plane CL.

  Moreover, the bead base line BL is a reference line on the bead portion side when the tire cross-section height SH is measured as shown in FIG.

  In the present embodiment, the carcass cord has been described as using a rayon cord as an example, but other than that, a nylon cord, a steel cord, a polyethylene cord, or the like may be used.

  Although it is known that rayon cords are generally decomposed by electron beam irradiation, nylon cords, steel cords, and polyethylene cords are not decomposed by electron beam irradiation. For example, after attaching rubber sheet 30 to carcass 14 However, it becomes possible to irradiate the electron beam including the carcass 14.

  Next, a method for manufacturing the pneumatic tire 10 according to the present embodiment will be described.

  First, the carcass 14 and the inner liner 28 are wound around a molding drum (not shown), and a rubber sheet 30 vulcanized in advance is disposed between the carcass 14 and the inner liner 28.

  At this time, the rubber sheet 30 is arranged in a region from the position corresponding to at least the tread end 20A of the pneumatic tire 10 to the position corresponding to the tire maximum width portion 24A.

  In the present embodiment, as an example, in the region from 60% of the tire half-width SW to the position of 15% of the tire cross-section height SH from the bead base line BL to the tire equatorial plane CL in the pneumatic tire 10. The rubber sheet 30 is arranged.

  The rubber sheet 30 vulcanized in advance has a thickness of 0.3 mm to 0.8 mm and a JIS hardness of 60 ° to 80 °.

  The rubber sheet 30 is vulcanized in advance so as to be in a vulcanized state of 50% to 70%. At this time, the entire region of the rubber sheet 30 is vulcanized in advance.

  The rubber sheet 30 is vulcanized using electron beam irradiation. The irradiation conditions at this time are an acceleration voltage of electron beam irradiation of 300 kV to 700 kV and a radiation dose of 3 MRAD to 7 MRAD. By doing in this way, JIS hardness 60 degrees-80 degrees can be obtained as mentioned above.

  In addition, JIS hardness is the hardness measured using the type A testing machine in the durometer hardness test according to JIS K6253.

  Then, the vulcanized state of the rubber sheet 30 is set to 100% at the time of vulcanization molding of the raw tire described later.

  If the vulcanized state of the rubber sheet 30 to be vulcanized in advance is less than 50%, a desired hardness cannot be obtained. For this reason, a carcass cord (not shown) is attached to the inner liner 28 during vulcanization molding of a raw tire. The effect of preventing the corresponding irregularities from appearing cannot be exhibited.

  In addition, when the vulcanized state of the rubber sheet 30 to be vulcanized in advance exceeds 70%, the hardness becomes too high, and thus the flexibility cannot be ensured in the rubber sheet 30 and the working efficiency is lowered. It will be.

  Then, tire components such as the bead core 12, the tread rubber 18, the side rubber 22, and the belt 26 are bonded to the carcass 14, the inner liner 28, and the rubber sheet 20 set as described above to form a tire assembly. The assembly is formed by a known method to form a green tire.

  Subsequently, this green tire is vulcanized by a known method. At this time, the pneumatic tire 10 is formed by inflating the raw tire by 1% to 3% using a bladder (not shown) to the maximum tire diameter.

  Further, by vulcanizing and molding the raw tire in this way, the vulcanized state of the rubber sheet 30 becomes 100%.

  Next, the effect of the manufacturing method of the pneumatic tire 10 which concerns on this embodiment is demonstrated.

  As in the present embodiment, before the step of vulcanizing the raw tire 10 when the pneumatic tire 10 is a raw tire, at least the tread end 20A of the pneumatic tire 10 is interposed between the carcass 14 and the inner liner 28. If a rubber sheet 30 vulcanized in advance is disposed in a region extending from a position corresponding to the tire maximum width portion 24A to a position corresponding to the tire maximum width portion 24A, a gap between the carcass 14 and the inner liner 28 is obtained during vulcanization molding of the raw tire. The rubber gauge is sufficiently secured.

  Thereby, it is possible to prevent the inner liner 28 from appearing unevenness corresponding to the carcass cord.

  Further, by disposing the rubber sheet 30 between the carcass 14 and the inner liner 28, the carcass 14 is expanded by the bladder via the inner liner 28 and the rubber sheet 30 in the process of vulcanizing and molding the raw tire. Therefore, the expansion force applied to the carcass 14 is made uniform.

  As a result, it is possible to prevent the arrangement of the carcass cords provided in the carcass 14 from being disturbed or the carcass 14 from being locally deformed. It is possible to prevent the appearance of irregularities corresponding to.

  Further, by vulcanizing the rubber sheet 30 in advance as described above, the hardness of the rubber sheet 30 can be increased in advance before the raw tire vulcanization molding process (about 15 times as 100% modulus). Thus, the flow of the rubber sheet 30 can be suppressed in the process of vulcanizing and molding the raw tire.

  This reliably prevents irregularities corresponding to the carcass cord from appearing on the inner liner 28.

  Moreover, according to this embodiment, even when a rayon cord is used for the carcass cord provided in the carcass 14, a rubber sheet 30 having a thickness of 0.3 mm to 0.8 mm is used for the vulcanized rubber sheet 30 in advance. As a result, a sufficient rubber gauge between the carcass 14 and the inner liner can be secured, so that unevenness corresponding to the carcass cord can be prevented from appearing on the inner liner 28.

  If the thickness of the rubber sheet is less than 0.3 mm, there is a possibility that the effect of suppressing the unevenness corresponding to the carcass cord from appearing on the inner liner 28 may not be exhibited.

  Further, if the thickness of the rubber sheet 30 is greater than 0.8 mm, the rubber gauge between the carcass 14 and the inner liner 28 becomes excessive, which may affect the performance of the pneumatic tire 10 as a product tire.

  Further, as in this embodiment, when a rubber sheet 30 vulcanized in advance having a JIS hardness of 60 ° to 80 ° is used, the flow of the rubber sheet 30 is suppressed in the process of vulcanizing and molding the raw tire. Therefore, the effect of suppressing the appearance of irregularities corresponding to the carcass cord on the inner liner 28 can be effectively exhibited, and at the same time, the rubber sheet 30 can be secured with flexibility. Thus, it is possible to prevent the work efficiency from being lowered.

  If the JIS hardness of the rubber sheet 30 is lower than 60 °, the flow of the rubber sheet 30 cannot be suppressed in the process of vulcanizing and molding the raw tire, and irregularities corresponding to the carcass cord appear on the inner liner 28. There is a possibility that the effect of suppressing the above will not be exhibited.

  Moreover, when the JIS hardness of the rubber sheet 30 is higher than 80 °, the rubber sheet 30 becomes too hard, and the working efficiency may be reduced.

  Furthermore, when the pneumatic tire 10 is formed by inflating the raw tire by 1% to 3% with the maximum tire diameter during vulcanization molding as in this embodiment, the target tire rigidity is obtained. In addition, the effect of suppressing the appearance of irregularities corresponding to the carcass cord on the inner liner 28 can be effectively exhibited.

  At this time, if the expansion of the raw tire is less than 1%, the desired rigidity cannot be obtained, and if the expansion of the raw tire is greater than 3%, the inner liner 28 has irregularities corresponding to the carcass cord. The possibility increases.

  By the way, the region from 60% of the tire half-width SW to the position of 15% of the tire cross-section height SH from the bead base line BL to the position of 15% of the tire cross-section height from the tire equatorial plane CL in the pneumatic tire 10 It is a part accompanied by a bending with a small radius of curvature as compared with the part, and the carcass cord is easy to move to the inside of the tire.

  Therefore, by arranging the rubber sheet 30 in this region as in this embodiment, it is possible to reliably suppress the appearance of irregularities corresponding to the carcass cord on the inner liner 28.

  As described in detail above, according to the method for manufacturing the pneumatic tire 10 according to the present embodiment, in the step of vulcanizing and molding the raw tire, a rubber gauge between the carcass 14 and the inner liner 28 can be sufficiently secured, In addition, by making the expansion force applied to the carcass 14 uniform, it is possible to prevent the arrangement of the carcass cord from being disturbed and the carcass 14 from being locally deformed. It is possible to prevent the unevenness corresponding to the carcass cord from appearing on the surface.

  Next, evaluation of the method for manufacturing a pneumatic tire according to the present embodiment will be described.

  In order to confirm the effect of the present invention, the pneumatic tire manufacturing method according to the present embodiment to which the present invention is applied and the pneumatic tire manufacturing method according to the comparative example are evaluated.

  In the evaluation, for the pneumatic tire manufactured by the manufacturing method of each pneumatic tire, it is observed whether irregularities corresponding to the carcass cord appear on the inner liner.

  The pneumatic tire to be manufactured is a tire for passenger cars, and the size is PSR225 / 40R18.

  Table 1 shows the number of prototypes and the prototype tires of the pneumatic tire manufactured by the pneumatic tire manufacturing method according to this example and the pneumatic tire manufactured by the pneumatic tire manufacturing method according to the comparative example. Among them, the number of tires in which irregularities corresponding to carcass cords appear on the inner liner (the number of tires in which a cord appearance phenomenon occurs) is shown.

  The pneumatic tire according to the present example shown in Table 1 is manufactured by the method shown in the above embodiment, and a rayon cord is used for the carcass cord, and the rubber sheet has a thickness of 0.6 mm and a JIS hardness. Is 75 °, and the raw tire is expanded by 2% to the maximum tire diameter during vulcanization molding.

  Further, in the pneumatic tire according to the present embodiment, rubber is provided in a region extending from a position of 60% of the tire half-width SW to the position of 15% of the tire cross-section height SH from the bead base line than the tire equatorial plane in the pneumatic tire. A sheet is arranged (length 380 mm).

  In addition, about the manufacturing method of the pneumatic tire which concerns on a present Example, in order to confirm the effect more correctly, manufacture is divided into 2 times and evaluated.

  On the other hand, the pneumatic tire according to the comparative example shown in Table 1 is vulcanized simultaneously with other components in the raw tire vulcanization process without previously vulcanizing the rubber sheet in the method shown in the above embodiment. It is what I did. Other conditions such as the material of the carcass cord, the thickness of the rubber sheet, the JIS hardness, the expansion rate at the time of vulcanization molding, the arrangement position and the length are the same as those of the pneumatic tire according to the present embodiment.

  Table 1 shows the results for the pneumatic tires manufactured by the pneumatic tire manufacturing method according to this example and the pneumatic tire manufacturing method according to the comparative example.

  As shown in the results of Table 1, in the pneumatic tire manufacturing method according to the comparative example, irregularities corresponding to the carcass cord appeared on the inner liner in all 30 trial tires, but this example In the method for manufacturing a pneumatic tire according to the present invention, no irregularities corresponding to the carcass cord appeared on the inner liner in any of the manufacturing lots.

  From this, according to the manufacturing method of the pneumatic tire of this embodiment, it was proved that there was an effect of preventing irregularities corresponding to the carcass cord from appearing on the inner liner after vulcanization molding of the raw tire. .

FIG. 1 is a cross-sectional view showing a configuration of a pneumatic tire according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Bead core 14 Carcass 16 Bead filler 18 Tread rubber 20 Tread part 20A Tread end 22 Side rubber 24 Side wall part 24A Tire maximum width part 26 Belt 28 Inner liner 30 Rubber sheet

Claims (5)

A pair of left and right bead cores extending along the tire circumferential direction;
At least a carcass ply that spans a toroidal shape between the pair of left and right bead cores and is folded and locked to each of the pair of left and right bead cores, and a plurality of parallel carcass cords are covered with rubber. A carcass made of one layer;
A tread rubber provided on the outer side in the tire radial direction of the carcass and constituting a tread portion;
A pair of left and right side rubbers that are provided on the outer side in the tire axial direction of the carcass and constitute sidewall portions;
An inner liner provided inside the tire of the carcass;
In the manufacturing method of the pneumatic tire provided with
The tire maximum width from a position corresponding to at least the tread end of the pneumatic tire between the carcass and the inner liner before the step of vulcanizing the raw tire when the pneumatic tire is a raw tire. A method for producing a pneumatic tire, comprising a step of arranging a rubber sheet pre-vulcanized in a region reaching a position corresponding to a portion. Using a rayon cord for the carcass cord,
The method for producing a pneumatic tire according to claim 1, wherein a rubber sheet having a thickness of 0.3 mm to 0.8 mm is used for the rubber sheet vulcanized in advance.   The method for producing a pneumatic tire according to claim 1 or 2, wherein the rubber sheet vulcanized in advance has a JIS hardness of 60 ° to 80 °.   The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is formed by expanding the green tire to a maximum tire diameter of 1% to 3% during vulcanization molding. A method for manufacturing a tire. The length measured along the tire axial direction from the tire equatorial plane to the tire maximum width portion measured in an unloaded state in which the pneumatic tire is mounted on a standard rim and filled with a specified internal pressure is defined as a tire half width SW, and a bead When the length from the baseline to the tire radial direction outermost position along the tire radial direction is the tire cross-section height SH,
The rubber sheet is arranged in a region from a position of 60% of the tire half-width SW to a position of 15% of the tire cross-section height SH from the bead base line to the tire equatorial plane of the pneumatic tire. The method for manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein:

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