JP2009051297A - Manufacturing method of pneumatic tire, and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire in which the cavity resonance of the tire is restricted while keeping heat dissipation at a tread, and road noise is reduced, and a method for manufacturing the pneumatic tire facilitating a sound absorbing layer adhering operation when such a pneumatic tire is manufactured. <P>SOLUTION: This pneumatic tire 1 has an annular sound insulation layer 13 formed of a porous material and extending circumferentially along the tire within a predetermined range on the inner surface of an inner liner 10 between a position of a bead toe 3 at a bead 4 and an inner surface position 12 at a tread ground contact end. Such a sound insulation layer 13 has protrusions 14 extending from the outside of the sound insulation layer 13 in a tire diameter direction toward the tire diameter direction and protruded to the inner side of a tire width direction, and when the number of protrusions 14 is defined as N, a distance in a tire diameter direction extending from the bead toe 11 to the outer periphery of the sound insulation layer 13 is defined as A, and a distance in a tire diameter direction extending from the bead toe 11 to the inner periphery of the sound insulation layer 13 is defined as B, a height h of the protrusion 14 is lower than π(A-B)/N. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides an annular sound absorbing layer made of a porous material and extending in the tire circumferential direction within a predetermined range between the bead toe position of the bead portion and the inner surface position of the tread grounding end on the inner surface of the inner liner. The present invention relates to a pneumatic tire, and particularly, while ensuring heat dissipation of the pneumatic tire, suppresses cavity resonance and reduces road noise. Further, the present invention provides an annular shape made of a porous material and extending in the tire circumferential direction within a predetermined range between the bead toe position of the bead portion and the end position in the tire width direction of the belt layer on the inner surface of the inner liner. The present invention relates to a method for manufacturing a pneumatic tire having a sound absorbing layer, and particularly facilitates such a manufacturing method.

  In a pneumatic tire assembled in a rim and attached to a vehicle, the tread portion oscillates against the road surface unevenness while the vehicle is running, so that air filled in the tire cavity resonates. This cavity resonance is a main cause of so-called road noise, and many of the resonance frequencies exist in the range of 180 to 300 Hz. When the road noise is transmitted to the vehicle interior, unlike a noise in other frequency bands, it takes a sharp and high peak value, which is annoying noise for passengers in the vehicle interior.

  In order to suppress such cavity resonance and reduce road noise, Patent Document 1 discloses a ring for sound control made of a porous material in a tire lumen formed by a rim and a pneumatic tire attached to the rim. A pneumatic tire having a sound absorbing layer fixed in the tire circumferential direction has been proposed. However, in the invention described in Patent Document 1, although road noise during traveling can be effectively reduced, a belt-like sheet made of foam or the like obtained by foaming rubber or synthetic resin is used as an inner liner on the inner peripheral side of the tread portion. In addition, the belt-like sheet extends in the circumferential direction and is firmly attached, and the heat insulating function is also exhibited. Therefore, the heat generated in the tread portion is smoothly transferred into the lumen defined by the pneumatic tire and the rim. There was an inconvenience that it was impossible to dissipate.

Japanese Patent No. 3622957

  In order to solve such problems of the prior art, the applicant of the present application disclosed in Japanese Patent Application No. 2006-329816 the material, thickness, and thickness of the sound absorbing layer affixed to the inside of the tread. By optimizing the length in the tire width direction, while suppressing such cavity resonance and reducing road noise, when the tread part generates heat, it dissipates heat from the sound absorbing layer and suppresses destruction of the tread part. Proposing pneumatic tires. However, in such a pneumatic tire, when the tread portion is punctured, the sound absorbing layer is stuck on the inner surface of the inner liner of the tread portion, so that puncture repair becomes difficult and the work efficiency may be reduced. . For example, when repairing a puncture by attaching a plug-type patch from the inside of the tire, there is a sound absorbing layer that hinders work, or it is sealed in the tire and solidified as the tire loads rolling. When repairing puncture using a sealing agent that seals, even if the sealing agent is sealed in the tire, the sound absorbing layer may absorb the sealing agent and prevent it from reaching the failure location. . Furthermore, the tire uniformity may be significantly deteriorated by such adsorption. As a solution, generally, the sound absorbing layer is not attached on the inner surface of the inner liner of the tread portion, but is disposed within a predetermined range between the bead portion and the shoulder portion on the inner surface of the inner liner. Pneumatic tires are conceivable. However, in such a pneumatic tire, if the sound absorbing layer is thickened in order to enhance the effect of suppressing cavity resonance, the sound absorbing layer may insulate the heat generated from the bead portion and the shoulder portion and reduce the heat dissipation of the sidewall portion. On the other hand, if the sound absorbing layer is thinned to ensure heat dissipation, the volume of the sound absorbing layer may be insufficient and cavity resonance may not be sufficiently suppressed. In addition, it is difficult to form the belt-like member in an annular shape on the inner surface of the tire having a diameter difference.

  Accordingly, it is an object of the present invention to solve these problems, and its object is to reduce road noise by suppressing cavity resonance of the tire while ensuring heat dissipation of the tread portion. Is to provide a pneumatic tire. Another object of the present invention is to provide a method for manufacturing a tire that facilitates attaching of the sound absorbing layer in manufacturing the tire as described above.

  In order to achieve the above object, the first invention comprises a porous material on the inner surface of the inner liner and within a predetermined range between the bead toe position of the bead portion and the inner surface position of the tread grounding end. In a pneumatic tire having an annular sound absorbing layer extending in the circumferential direction, the sound absorbing layer has a protruding portion that extends from the outer side in the tire radial direction of the sound absorbing layer to the inner side in the tire radial direction and protrudes inward in the tire width direction. When the number of protrusions is N (N is a natural number), the tire radial distance from the bead toe to the outer periphery of the sound absorbing layer is A, and the tire radial distance from the bead toe to the inner periphery of the sound absorbing layer is B, The pneumatic tire is characterized in that the height h of the protruding portion is π (AB) / N or less. With this configuration, the sound absorbing layer ensures heat dissipation in the area where the protrusion is not provided, and the sound wave generated by the cavity resonance collides with the protrusion and is diffusely reflected. The rate is reduced and the volume of the sound absorbing layer increases due to the provision of the protruding portion, so that the energy attenuation efficiency of the sound wave that has entered the sound absorbing layer is improved, thereby suppressing the cavity resonance and loading. Noise can be effectively reduced.

  The “inner surface position of the tread grounding end” here means that a tire is assembled to a standard rim (or “Approved Rim” or “Recommended Rim”) at an applicable size described in the following standard, When applying the maximum air pressure specified in the same standard to a flat plate in a stationary state and applying a maximum load load (a load corresponding to 88% of the maximum load capacity), look at the cross section in the tire width direction. The position corresponding to the intersection of the inner surface of the tire with the perpendicular line extending from the outermost end in the tire width direction on the contact surface with the flat plate to the inner surface of the inner liner. The standard refers to an industrial standard effective in an area where tires are produced or used. For example, in the United States, the Tire and Rim Association Inc. “Year Book” in Europe, “Standard Manual” of The European Tire and Rim Technical Organization in Europe, and “JATMA Year Book” of Japan Automobile Association in Japan. Further, the “height of the protruding portion” herein refers to the height of the protruding portion of the sound absorbing layer measured along the normal line standing on the inner surface of the tire. The air here can be replaced with an inert gas such as nitrogen gas.

  Moreover, it is preferable that the height of the protruding portion gradually decreases from the inner side in the tire radial direction toward the outer side in the tire radial direction.

  Furthermore, it is preferable that the sound absorbing layer is separated from the bead toe position of the bead part by 10 mm or more to the tread part side along the peripheral of the tire inner surface.

  Furthermore, it is preferable that the sound absorbing layer is spaced 10 mm or more on the bead toe side along the periphery of the tire inner surface from the inner surface position of the innermost belt layer in the tire width direction. Here, “the inner end position of the innermost belt layer in the tire width direction” means that the tire is applied to a standard rim (or “Applied Rim” or “Recommended Rim”) in the applicable size described in the above standard. Assembling, tire diameter in the tire width direction cross section in the ground contact state under the condition of applying the maximum load (maximum load capacity) and the air pressure corresponding to the maximum load in the applicable size described in the above standard The position corresponding to the intersection of the normal line extending from the edge in the tire width direction of the innermost belt layer, which is the innermost belt layer in the direction, to the inner surface of the inner liner, and the inner surface of the tire, that is, the inner surface of the sound absorbing layer It shall be said.

  In addition, it is preferable that the sound absorbing layer is composed of a single band-shaped member.

  The second invention is an annular sound absorbing layer made of a porous material and extending in the tire circumferential direction within a predetermined range between the bead toe position of the bead portion and the inner surface position of the tread grounding end on the inner surface of the inner liner. When manufacturing a pneumatic tire comprising a belt-like member having a length corresponding to the outer peripheral length of the predetermined range, and corresponding to the predetermined range of the unvulcanized or vulcanized tire body The belt-shaped member is bent along the tire circumferential direction, and the tire radial distance from the bead toe to the outer periphery of the sound absorbing layer is defined as A at N locations on the circumference (N is a natural number). When the distance in the tire radial direction from the bead toe to the inner periphery of the sound absorbing layer is B, a projecting portion whose height h is π (AB) / N or less is formed to constitute the sound absorbing layer. With a featured pneumatic tire manufacturing method That. Since it is difficult to form a belt-like member in an annular shape on the inner surface of a tire having a difference in diameter, by adopting such a tire manufacturing method, a single belt-like member is used to form a protrusion. Since the sound absorbing layer can be configured, the tire can be easily manufactured.

  According to the present invention, a pneumatic tire in which road noise is reduced by suppressing the cavity resonance of the tire while ensuring heat dissipation in the tread portion, and sound absorption in manufacturing such a pneumatic tire. It is possible to provide a method for manufacturing a tire that facilitates the application of a layer.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross section in the tire width direction of an assembly of a tire and a rim formed by mounting a typical pneumatic tire (hereinafter referred to as “tire”) according to the present invention on a rim. FIG. 2 is a side view of the sound absorbing layer of the tire according to the present invention. FIG. 3 is a view showing a belt-like member used for constituting the sound absorbing layer according to the present invention.

  The pneumatic tire 1 according to the present invention includes a tread portion 2 that contacts a road surface, a pair of sidewall portions 3 that extend inward in the tire radial direction from both side portions of the tread portion 2, and tires of the sidewall portions 3. A tire body 5 is constituted by a pair of bead portions 4 provided in the radial direction and fitted to the rim R. Inside the tire body 5, a bead core 6, 6 embedded in each bead portion 4 extends in a toroidal shape to form a skeleton structure of the tire body 5, for example, a radial structure carcass 7, and a crown area of the carcass 7. A belt 8 that reinforces the tread portion 2 is provided. An air-impermeable inner liner 10 is disposed on the inner surface side of the tire body 5, that is, on the side facing the tire lumen 9 defined by the tire 1 and the rim R.

  On the inner surface of the inner liner 10, an annular sound absorbing material made of a porous material and extending in the tire circumferential direction within a predetermined range between the position of the bead toe 11 of the bead portion 4 and the inner surface position 12 of the tread grounding end. It comprises a layer 13. The sound absorbing layer 13 has, on the inner surface of the tire 1, protrusions 14 that extend in the tire radial direction from the outer side in the tire radial direction and protrude inward in the tire width direction. The number of the protruding parts 14 is N (N is a natural number). ), The tire radial direction distance from the bead toe 11 to the outer periphery of the sound absorbing layer 13 is A, and the tire radial direction distance from the bead toe 11 to the inner periphery of the sound absorbing layer 13 is B, the height h of the protrusion 14 is , Π (A−B) / N or less. In the tire having such a configuration, the sound absorbing layer 13 ensures that the sound wave generated as a result of cavity resonance is generated in the projecting portion 14 while ensuring heat dissipation from the bead portion 4 and the shoulder portion in the region where the projecting portion 14 is not disposed. Since the sound is reflected by collision, the reflectance of the sound wave on the surface of the sound absorbing layer 13 is reduced, and the volume of the sound absorbing layer 13 is increased by providing the projecting portion 14, so that the energy of the sound wave that has entered the sound absorbing layer 13 is increased. Attenuation efficiency is improved, and it is possible to suppress cavity resonance and effectively reduce road noise. However, when the height h of the protruding portion 14 exceeds π (A−B) / N, the protruding portion 14 becomes too high, so that the protruding portion 14 vibrates with the rolling of the tire and a new one is generated. Cavity resonance is generated, and road noise is generated. Moreover, if the height h of the protrusion 14 becomes too high, the mass increases, and deformation due to centrifugal force during high-speed rotation of the tire 1 increases, so the uniformity of the tire 1 decreases. On the other hand, in this invention, since the height h of the protrusion part 14 is made into the said range, there is no these problems.

  Moreover, it is preferable that the height of the protrusion 14 gradually decreases from the inner side in the tire radial direction toward the outer side in the tire radial direction. This is because the tire width direction end 16 of the belt layer 4 is likely to generate heat due to repeated shear deformation accompanying rolling of the tire load, and therefore the belt layer becomes thinner as the outer circumferential sound absorbing layer 13 becomes thinner in the tire radial direction. This is because the sound absorbing layer 13 in the vicinity of the tire width direction end 16 of the tire 4 becomes too thick, and it is possible to effectively dissipate heat without degrading heat dissipation. In addition, it is preferable that the height of the sound absorption layer 13 is 1-50 mm. This is because if less than 1 mm, the sound absorption effect may be reduced, while if exceeding 50 mm, deformation due to centrifugal force during high-speed rotation of the tire 1 increases due to an increase in mass. This is because problems such as peeling of the sound absorbing layer 13 may occur.

  Furthermore, it is preferable that the distance p1 at which the sound absorbing layer 13 is separated from the position of the bead toe 11 of the bead part 4 along the peripheral of the tire inner surface is 10 mm or more on the tread part side. This is because when the distance p1 at which the sound absorbing layer 13 is separated from the bead toe 11 position of the bead portion 4 is less than 10 mm, the inner end in the tire radial direction of the sound absorbing layer 13 is too close to the bead toe 11 position. This is because the sound absorbing layer 13 may come into contact with the rim R, and the contact portion of the sound absorbing layer 13 may be damaged, or dirt may be generated due to sliding with the rim R, and the sound absorbing layer 13 may be altered. .

  Furthermore, it is preferable that the distance p2 that the sound absorbing layer 13 is separated from the innermost belt layer end position 15 in the tire width direction along the peripheral of the tire inner surface is 10 mm or more on the bead toe 11 side. This is because when the distance p2 at which the sound absorbing layer 13 is separated from the inner surface position 15 of the innermost belt layer in the tire width direction is less than 10 mm, the outer end in the tire radial direction of the sound absorbing layer 13 is the tire width of the innermost belt layer. Because it is too close to the direction end inner surface position 15, when heat is generated from the end 16 in the tire width direction of the belt layer 8, the sound absorbing layer 13 in the vicinity of the belt layer 8 may insulate, and heat dissipation may be reduced. is there.

  In addition, the sound absorbing layer 13 is preferably composed of a single band-like member 17 as shown in FIG. This is because, when the sound absorbing layer 13 is formed by attaching a plurality of strip-like members 17, it is difficult to apply the sound absorbing layer 13 at a constant interval, and the uniformity of the tire 1 may be reduced.

  In addition, it is preferable that at least 2 to 16 protrusions 14 are arranged along the tire circumferential direction. This is because when there is only one projecting portion 14, the number of projecting portions from which sound waves are irregularly reflected becomes too small, and the reflectivity of sound waves on the surface of the sound absorbing layer 13 is not reduced, but cavity resonance is suppressed and load is reduced. There is a possibility that noise cannot be effectively reduced. On the other hand, when there are more than 16 protrusions 14, when the protrusions 14 vibrate, there are too many protrusions 14; This is because there is a possibility that road noise is generated due to the excessive vibration due to the synergistic effect. The protrusions 14 may be arranged at any pitch from the viewpoint of the sound absorption effect, but from the viewpoint of uniformity, the protrusions 14 are arranged at substantially equal pitches in the tire circumferential direction as shown in FIG. It is preferable.

  In addition, the porous material constituting the sound absorbing layer 13 can be constituted by a foam of rubber or synthetic resin, or a nonwoven fabric made of synthetic fiber, plant fiber or animal fiber, having an open cell structure or closed cell structure. . And when comprising a porous material with a nonwoven fabric, in order to demonstrate a required sound-absorbing effect, the specific gravity shall be in the range of 0.1-2.0, and the average diameter of a fiber is set. It is preferable to set it as 0.1-200 micrometers. Further, the sound absorbing layer 13 has a width of 0.1 to 0.1 along the periphery between the position of the bead toe 11 of the bead portion 4 and the inner surface position 15 of the innermost belt layer in the tire width direction on the inner surface of the inner liner 10. It is preferable to paste with a width of 0.9 times.

  Next, the manufacturing method which manufactures the tire 1 according to this invention is demonstrated below. Such a manufacturing method is made of a porous material and extends in the tire circumferential direction within a predetermined range between the position of the bead toe 11 of the bead portion 4 and the position of the inner surface 12 of the tread grounding end on the inner surface of the inner liner 10. In manufacturing the tire 1 including the annular sound absorbing layer 13, a belt-like member 17 having a length corresponding to the outer peripheral length of the predetermined range and made of a porous material is used as an unvulcanized or vulcanized tire body. The belt-like member 17 is bent at a position corresponding to a predetermined range of 5 along the tire circumferential direction, and bent from the bead toe 11 to the outer periphery of the sound absorbing layer 13 at N places (N is a natural number) on the circumference. , Where A is the tire radial distance, and B is the tire radial distance from the bead toe 11 to the inner periphery of the sound absorbing layer 13, the height h is π (AB) / N or less. Forming the sound absorbing layer 13. It is characterized in that. Since it is difficult to form the belt-like member 17 in an annular shape on the inner surface of the tire 1 having a difference in diameter, the belt-like member used for forming the sound absorbing layer 13 by adopting such a manufacturing method of the tire 1. Since it becomes unnecessary to preliminarily mold 17 into a special shape and a single band member 17 as shown in FIG. 3 can be used, the sound absorbing layer 13 having the protruding portion 14 can be configured. 1 can be easily manufactured. In general, when the belt-like member 17 provided with the protrusions 14 is prepared in advance, the production cost thereof becomes high. However, by adopting the method for manufacturing the tire 1 according to the present invention, a single piece that can be produced at low cost. Since the sound absorbing layer 13 having the protrusions 14 can be configured using the belt-like member 17, the tire 1 can be manufactured at low cost.

  When the belt-like member 17 is attached to the vulcanized tire body 5, a styrene-butadiene rubber latex adhesive, an aqueous polymer-isocyanate adhesive, or an acrylic or synthetic resin adhesive tape is used. Can be chemically bonded to the inner surface of the inner liner 10, and when the belt-like member 17 is attached to the unvulcanized tire body 5, it is temporarily fixed with such an adhesive tape or adhesive, and then heated and heated. The belt-like member 17 can be impregnated on the inner surface of the inner liner 10 and physically fixed by vulcanization molding by pressurization.

  The above description shows only a part of the embodiment of the present invention, and these configurations can be combined alternately or various changes can be made without departing from the gist of the present invention.

  Next, a conventional tire without a sound absorbing layer (conventional tire), a tire of a comparative tire with a sound absorbing layer provided from the shoulder portion to the bead portion 4 and having no protrusions (comparative tire) Further, tires (Example tires 1 to 11) having a sound absorbing layer according to the present invention were prototyped and evaluated for performance as radial tires for passenger cars of tire size 215 / 45R17, and will be described below. In addition, although Example tires 1-11 were manufactured according to the method of the present invention, at that time, the sound absorbing layer could not be wrinkled or torn and could be stuck smoothly.

A conventional tire that does not include a sound absorbing layer, a comparative tire that includes a sound absorbing layer, and a single band-shaped member made of a porous material are attached in the tire circumferential direction to form a sound absorbing layer having a protrusion. Example tires 1 to 11 have the specifications shown in Table 1, respectively. As shown in Table 1, the number of protrusions is N, the distance in the tire radial direction from the bead toe to the outer periphery of the sound absorbing layer is A, and the distance in the tire radial direction from the bead toe to the inner periphery of the sound absorbing layer is B. The height h is π (A−B) / N or less, and gradually decreases from the inner side in the tire radial direction toward the outer side in the tire radial direction. The inner diameter Dr of the rim is 434.6 mm, and the outer diameter Dt of the tire is 626.0 mm. The sound absorbing layer is configured using a polyethylene terephthalate (PET) nonwoven fabric having a basis weight of 500 g / m ² . Further, the sound absorbing layer of the comparative example tire is the same in size and material as the sound absorbing layer of the example tire except that the protruding portion 14 is provided.

  Each of these test tires is attached to a rim of size 17.0 × 7.5JJ to form a tire wheel, mounted on a vehicle in a state where air pressure: 210 kPa (relative pressure) and tire load load: 3.92 kN are applied. It was used for various evaluations.

  The vehicle traveled on an asphalt road surface at 60 km / h, and the in-vehicle noise at the driver's seat was measured. This measurement result was subjected to frequency analysis, and the suppression effect of the cavity resonance was evaluated based on the peak sound pressure level seen near 230 kHz. The evaluation results are shown in Table 2. The evaluation results in the table are obtained by indexing the suppression effect of cavity resonance in the comparative example tire in which the sound absorbing layer is provided, that is, the amount of reduction in the sound pressure level, with respect to the conventional example tire in which the sound absorbing layer is not provided. As 100, the suppression effect in Example tires 1 to 11 is expressed as a relative value. In addition, it has shown that the suppression effect of cavity resonance is so large that a numerical value is large.

  As is clear from the results in Table 2, noise due to cavity resonance was reduced in the comparative example tire compared to the conventional example tire. Compared with the comparative example tire, the example tires 1 to 11, particularly the example tires 4 and 5, had reduced noise due to cavity resonance. In addition, the Example tires 1-11 ensured sufficient heat dissipation in the tread portion during rolling of the tire load, like the comparative example tires.

  As is clear from the above, the present invention manufactures a pneumatic tire with reduced road noise by suppressing cavity resonance of the tire while ensuring heat dissipation in the tread portion, and the pneumatic tire. In doing so, it has become possible to provide a tire manufacturing method that facilitates the attachment of the sound absorbing layer.

1 is a sectional view in the tire width direction of a typical tire according to the present invention assembled with a rim. FIG. It is a side view of the sound absorption layer of the tire according to this invention. It is the figure which showed the general strip | belt-shaped member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire 2 Tread part 3 Side wall part 4 Bead part 5 Tire main body 6 Bead core 7 Carcass 8 Belt layer 9 Tire lumen 10 Inner liner 11 Bead toe 12 Inner surface position of tread grounding end 13 Sound absorbing layer 14 Protruding part 15 Innermost belt layer Tire width direction end inner surface position 16 Belt width tire width direction end 17 Belt member R Rim X Tire center axis CL Tire equatorial plane Dr / 2 Tire radial direction distance Dt / 2 from tire center axis to rim Tire tread portion from tire center axis Tire radial distance to tread

Claims (6)

On the inner surface of the inner liner, a pneumatic structure comprising an annular sound absorbing layer made of a porous material and extending in the tire circumferential direction within a predetermined range between the bead toe position of the bead portion and the inner surface position of the tread grounding end. In the tire,
The sound absorbing layer has a protruding portion that extends in the tire radial direction of the sound absorbing layer and protrudes inward in the tire width direction. The number of the protruding portions is N (N is a natural number), and the sound absorbing layer extends from the bead toe. When the tire radial distance from the bead toe to the inner circumference of the sound absorbing layer is B and the tire radial distance from the bead toe is B, the height h of the protrusion is π (AB) / N A pneumatic tire characterized by:   The pneumatic tire according to claim 1, wherein the height of the protruding portion gradually decreases from the inner side in the tire radial direction toward the outer side in the tire radial direction.   3. The pneumatic tire according to claim 1, wherein the sound absorbing layer is separated from the bead toe position of the bead portion by 10 mm or more toward the tread portion side along the peripheral of the tire inner surface.   The pneumatic according to any one of claims 1 to 3, wherein the sound absorbing layer is spaced 10 mm or more from the inner position of the innermost belt layer in the tire width direction end along the periphery of the tire inner surface toward the bead toe side. tire.   The pneumatic tire according to any one of claims 1 to 4, wherein the sound absorbing layer is configured by a single band-shaped member. On the inner surface of the inner liner, a pneumatic structure comprising an annular sound absorbing layer made of a porous material and extending in the tire circumferential direction within a predetermined range between the bead toe position of the bead portion and the inner surface position of the tread grounding end. In manufacturing tires,
A belt-shaped member having a length corresponding to the outer peripheral length of the predetermined range and made of a porous material is aligned in a tire circumferential direction at a position corresponding to the predetermined range of an unvulcanized or vulcanized tire body. The belt-shaped member is bent, and the distance in the tire radial direction from the bead toe to the outer periphery of the sound absorbing layer is A at N locations (N is a natural number) on the circumference, and the inside of the sound absorbing layer from the bead toe A pneumatic structure characterized in that when the distance in the tire radial direction to the circumference is B, the height h is π (A−B) / N or less to form a protruding portion to constitute the sound absorbing layer. Tire manufacturing method.

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