Pneumatic tire and method of manufacturing same

Abstract

To provide a pneumatic tire that has its sealant layer suppressed from varying in thickness as a sealant material has a reduced overlap region, and is improved in adhesion of a sound absorption layer to the sealant layer.SOLUTION: The pneumatic tire comprises a sealant layer 60 arranged on a tire inner bore side of an inner liner 50, and a sound absorption layer 70 arranged on a tire inner bore side of the sealant layer 60. The sealant layer 60 is formed of a belt-like sealant material 61 wound and stuck around an inner surface 501 of the inner liner 50, and the sealant layer 60 has a plurality of annular circulation parts 62 arranged in parallel so that the sealant material 61 is in an adjacent state in a tire width direction, and parallel with the tire circumferential direction, and a plurality of transition parts 63 which is provided in part in the tire circumferential direction of the circulation parts 62, and allows the sealant material 61 to transition to the circulation part 62 adjoining one side in the tire width direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire for a vehicle and a method for manufacturing the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, pneumatic tires have been known that have a puncture prevention function in which a hole formed in the tire in the event of a puncture is automatically sealed by a sealant layer provided on the inner surface of the tire. For example, Patent Document 1 describes a pneumatic tire in which a sealant layer is formed from a roughly string-shaped sealant material that is applied continuously in a spiral shape along the inner surface of the tire, and a sound-absorbing layer is provided on the inside of the sealant layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6184523 Summary of the Invention [Problem to be solved by the invention]

[0004] When the sealant is applied in a spiral shape, a long overlapping area of ​​the sealant exists in the circumferential direction at both ends in the tire width direction, that is, the first and last turns of the sealant. If the overlapping area of ​​the sealant is large, the thickness of the sealant layer varies widely and the adhesion of the sound absorbing layer to the sealant layer decreases.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a pneumatic tire and a manufacturing method thereof in which the overlapping area of ​​the sealant material is reduced, thereby suppressing variation in the thickness of the sealant layer and improving the adhesion of the sound-absorbing layer to the sealant layer. [Means for solving the problem]

[0006] The pneumatic tire of the present invention includes a pair of beads, a pair of sidewalls extending radially outward from each of the pair of beads, a tread disposed between the pair of sidewalls, a carcass ply spanning between the pair of beads, an inner liner disposed on the tire cavity side of the carcass ply, a sealant layer disposed on an inner surface of the inner liner on at least the tire cavity side corresponding to the tread, and a sound absorbing layer disposed on the tire cavity side of the sealant layer, wherein the sealant layer is formed of a strip-shaped sealant material that is wrapped around and attached to the inner surface of the inner liner, and the sealant layer has a plurality of annular circumferential portions parallel to the tire circumferential direction in which the sealant material is arranged in parallel adjacent to each other in the tire width direction, and a plurality of transition portions provided in parts of the circumferential portions in the tire circumferential direction, at which the sealant material transitions to the circumferential portion adjacent to one side in the tire width direction.

[0007] The method for manufacturing a pneumatic tire of the present invention is a method for manufacturing a pneumatic tire that includes forming a sealant layer on the inner surface of the tire, and then disposing a sound absorbing layer on the tire cavity side of the sealant layer. In forming the sealant layer, the tire is continuously rotated around its axis while ejecting sealant material onto the inner surface of the tire from a nozzle disposed on the inner cavity side of the tire to form a ring-shaped circumferential portion made of sealant material parallel to the tire circumferential direction, and then, while ejecting the sealant material from the nozzle, the nozzle is moved relative to the tire in the tire width direction, and then sealant material is ejected from the nozzle onto the inner surface of the tire, thereby repeating the operation of forming the next circumferential portion made of sealant material adjacent to the circumferential portion on one side of the circumferential portion in the tire width direction, thereby forming a sealant layer on the inner surface of the tire in which a plurality of the circumferential portions are arranged in parallel in the tire width direction. Effect of the Invention

[0008] According to the present invention, it is possible to provide a pneumatic tire and a manufacturing method thereof in which the overlapping area of ​​the sealant material is reduced, the variation in thickness of the sealant layer is suppressed, and the adhesion of the sound-absorbing layer to the sealant layer is improved. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view in the tire width direction of a tire according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a development view showing the inner surface of a tire according to an embodiment of the present invention, and is a diagram showing a sealant layer and a sound absorbing layer in schematic form. [Diagram 3] FIG. 2 is a diagram illustrating a state in which a sealant material is applied to an inner surface of a tire by a nozzle when manufacturing a tire according to an embodiment of the present invention. [Figure 4] FIG. 1 is a development view of the inner surface of a tire, showing a conventional example in which a sealant material is attached in a spiral shape to the inner surface of the tire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a diagram showing a tire widthwise cross section of a tire 1, which is a pneumatic tire according to this embodiment. The tire 1 is, for example, a tire for passenger cars. The basic structure of the tire 1 is symmetrical in a cross section in the tire widthwise direction. In the figure, the symbol S1 indicates the tire equatorial plane. The tire equatorial plane S1 is a plane that is perpendicular to the tire rotation axis (tire meridian) and is located at the center in the tire width direction.

[0011] The cross-sectional view in Fig. 1 is a cross-sectional view in the tire width direction (cross-sectional view at the tire meridian) of a tire 1 mounted on a standard rim and inflated to a standard internal pressure in an unloaded state. The standard rim refers to a standard rim determined by JATMA for a tire size. The standard internal pressure is, for example, 180 kPa when the tire is for a passenger car.

[0012] Here, the tire width direction is a direction parallel to the tire rotation axis, and corresponds to the left-right direction on the paper surface in the cross-sectional view of Fig. 1. In Fig. 1, this direction is illustrated as tire width direction X. The inner side in the tire width direction is the direction approaching the tire equatorial plane S1, and is the center side of the paper in Fig. 1. The outer side in the tire width direction is the direction away from the tire equatorial plane S1, and is the left and right sides of the paper in Fig. 1. The tire radial direction is a direction perpendicular to the tire rotation axis, and is the up-down direction on the paper surface in Fig. 1. In Fig. 1, this direction is illustrated as tire radial direction Y. The outer side in the tire radial direction is the direction away from the tire rotation axis, and is the lower side on the paper in Fig. 1. The inner side in the tire radial direction is the direction approaching the tire rotation axis, and is the upper side on the paper in Fig. 1.

[0013] As shown in FIG. 1, the tire 1 includes a pair of beads 10 provided on both sides in the tire width direction, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 disposed between the pair of sidewalls 20, a carcass ply 40 disposed between the pair of beads 10, and an inner liner 50 disposed on the tire cavity side of the carcass ply 40.

[0014] The bead 10 includes a bead core 11, a bead filler 12 extending radially outward of the bead core 11, a chafer 13, and a rim strip rubber 14.

[0015] The bead core 11 is an annular member formed by winding a rubber-coated metal bead wire multiple times, and serves to fix the tire 1 filled with air to a rim. The bead filler 12 is a rubber member that tapers toward the outside in the tire radial direction. The bead filler 12 is a member provided to increase the rigidity of the peripheral portion of the bead 10 and ensure high maneuverability and stability. The bead filler 12 is made of rubber that is harder than the surrounding rubber members, for example.

[0016] The chafer 13 is provided on the inner side in the tire radial direction of the carcass ply 40 provided around the bead core 11. The rim strip rubber 14 is disposed on the outer side in the tire width direction of the chafer 13 and the carcass ply 40. The rim strip rubber 14 is a member that comes into contact with the rim on which the tire 1 is mounted.

[0017] The sidewall 20 includes a sidewall rubber 21 disposed on the outer side of the carcass ply 40 in the tire width direction. The sidewall rubber 21 constitutes the outer wall surface of the tire 1. The sidewall rubber 21 is the portion that bends the most when the tire 1 performs a cushioning function, and flexible rubber having fatigue resistance is usually used for the sidewall rubber 21.

[0018] The tread 30 includes an endless belt 31 , a cap ply 32 , and a tread rubber 33 .

[0019] The belt 31 is disposed on the outer side in the tire radial direction of the carcass ply 40. The cap ply 32 is disposed on the outer side in the tire radial direction of the belt 31. The belt 31 is a member that reinforces the tread 30. The belt 31 of this embodiment has a two-layer structure including an inner belt 311 and an outer belt 312. Both the inner belt 311 and the outer belt 312 have a structure in which a plurality of cords such as steel cords are covered with rubber. Note that the belt 31 is not limited to a two-layer structure, and may have a one-layer structure, or a three-layer or more structure.

[0020] The cap ply 32 is a member that reinforces the tread 30 together with the belt 31. The cap ply 32 has a structure in which a plurality of insulating organic fiber cords, such as polyamide fiber, are covered with rubber. By providing the cap ply 32, it is possible to improve durability and reduce road noise during driving.

[0021] The tread rubber 33 is disposed on the outer side of the cap ply 32 in the tire radial direction. The tread rubber 33 is a member that constitutes a tread surface (contact surface with the road surface) 331 during normal driving. The tread surface 331 of the tread rubber 33 is provided with a tread pattern 34 composed of, for example, a plurality of grooves. The tread pattern 34 has a plurality of main grooves 341 aligned in the tire width direction. Each of the plurality of main grooves 341 extends along the tire circumferential direction.

[0022] The carcass ply 40 constitutes a ply that serves as the framework of the tire 1. The carcass ply 40 is embedded in the tire 1 in a manner that passes between a pair of beads 10, a pair of sidewalls 20, and the tread 30. The carcass ply 40 includes a plurality of carcass cords that form the framework of the tire 1. The plurality of carcass cords extend, for example, in the tire width direction and are arranged side by side in the tire circumferential direction. The carcass cords are made of insulating organic fiber cords such as polyester or polyamide. The carcass ply 40 is formed by covering the plurality of carcass cords with rubber.

[0023] The carcass ply 40 has a ply body 401 extending from one bead core 11 to the other bead core 11 and extending between the tread 30 and the bead 10, a pair of bends 402 folded back from the ply body 401 at the bead core 11, and a pair of turn-up portions 403 extending outward in the tire radial direction from each of the bends 402. The ply body 401, the bends 402, and the turn-up portions 403 are continuous.

[0024] The ply body portion 401 is disposed on the inner side in the tire radial direction, on the inner side in the tire width direction, of the bead core 11 and the bead filler 12. The turned-up portion 403 is disposed on the outer side in the tire width direction, of the bead core 11 and the bead filler 12, on the inner side in the tire radial direction. In the portion other than the bead core 11 and the bead filler 12, the turned-up portion 403 is overlapped with the ply body portion 401. The bent portion 402 constitutes the innermost portion of the carcass ply 40 in the tire radial direction.

[0025] Although the carcass ply 40 in this embodiment has a single-layer structure, the carcass ply 40 is not limited to a single-layer structure, and may have a two-layer, three-layer or more layer structure.

[0026] The chafer 13 of the bead 10 described above is provided so as to surround the end portion on the inner side in the tire radial direction of the carcass ply 40 including the bent portion 402. The rim strip rubber 14 is disposed on the outer side in the tire width direction of the chafer 13 and the folded-up portion 403 of the carcass ply 40. The outer end portion in the tire radial direction of the rim strip rubber 14 is covered with the sidewall rubber 21 described above.

[0027] The inner liner 50 covers the inner surface of the tire between a pair of beads. The inner liner 50 covers the inner surface of the ply body portion 401 of the carcass ply 40 and the inner surfaces of the chafers 13 of the pair of beads 10. The inner liner 50 is made of air-resistant rubber and prevents air within the tire cavity from leaking to the outside.

[0028] As shown in FIG. 1, the tire 1 according to this embodiment further includes a sealant layer 60 and a sound absorbing layer 70.

[0029] The sealant layer 60 is disposed on at least the inner surface 501 of the inner liner 50 on the tire cavity side corresponding to the tread 30. The width of the sealant layer 60, i.e., the length dimension in the tire width direction, is, for example, about 1.1 times the width of the tread surface 331 of the tread 30, which is the ground contact width of the tire 1. The sealant layer 60 may be disposed so as to extend outward in the tire width direction from the tread 30 and include a part of the sidewall 20 on the tread 30 side. The sealant layer 60 is attached to the inner liner 50 by its own adhesiveness. The thickness of the sealant layer 60 is, for example, about 1 mm or more and 10 mm or less. The sound absorbing layer 70 is disposed on an inner surface 601 on the tire cavity side of the sealant layer 60. The sound absorbing layer 70 is attached to the sealant layer 60 by the adhesiveness of the sealant layer 60.

[0030] Fig. 2 is a development view showing the inner surface of the tire 1, and illustrates a sealant layer 60 and a sound absorbing layer 70 provided on the inner surface of the tire 1. In Fig. 2, arrow X indicates the tire width direction, and arrow Z indicates the tire circumferential direction.

[0031] 2, the sealant layer 60 is formed of a strip of sealant material 61 that is wrapped around the inner surface 501 of the inner liner 50 in the tire circumferential direction and attached to the inner surface 501. The sealant layer 60 has a plurality of annular circumferential portions 62 and a plurality of transition portions 63 formed by the sealant material 61.

[0032] In Fig. 2, reference numeral 61A denotes an application start end of the sealant 61, and reference numeral 61B denotes an application end end of the sealant 61. As shown in Fig. 2, the sealant 61 is applied continuously from one end side to the other end side in the tire width direction (from left to right in Fig. 2) while going around as shown by the arrow from the application start end 61A to the application end end 61B.

[0033] The circumferential portion 62 is formed by attaching the sealant material 61 to the inner surface 501 of the inner liner 50 parallel to the tire circumferential direction. The multiple circumferential portions 62 are arranged in parallel so as to be adjacent to each other in a state of close contact in the tire width direction. The multiple transition portions 63 are inclined at a predetermined angle with respect to the tire circumferential direction, and are arranged in parallel so as to be adjacent to each other in a state of close contact.

[0034] The transition portion 63 is provided in a part of the circumferential portion 62 in the tire circumferential direction. The transition portion 63 is a portion where the sealant material 61 transitions to one side in the tire width direction (the right side in FIG. 2 ) after the sealant material 61 is attached to the inner surface 501 of the inner liner 50 for approximately one revolution to form one circumferential portion 62. After passing through the transition portion 63, the next circumferential portion 62 is attached adjacently to one side in the tire width direction of the already attached circumferential portion 62. The next circumferential portion 62 adjacent to one side in the tire width direction is repeatedly formed after passing through the transition portion 63, and the sealant layer 60 is provided. In this embodiment, the multiple transition portions 63 are disposed at approximately the same positions in the tire circumferential direction, and are arranged in parallel in the tire width direction.

[0035] In this manner, when applying the sealant material 61 to the inner surface of the tire, the application method in which the circumferential portions 62 parallel to the tire circumferential direction are applied sequentially in the tire width direction, passing through the transition portions 63, may be referred to as step application below.

[0036] As the sealant 61, for example, a sealing material having adhesiveness, which is made by compounding unvulcanized or semi-vulcanized butyl rubber with a plasticizer such as polyisobutylene or polybutene, a tackifier such as a thermoplastic olefin / diolefin copolymer, and a filler such as carbon black or silica, can be used. However, the sealant 61 is not limited to this, and may be any other known sealing material that has been used conventionally.

[0037] Next, a method for manufacturing a tire according to this embodiment, which includes applying the sealant 61 in steps, will be described. 3, the sealant 61 can be applied in steps by discharging the sealant 61 from the nozzle 100 onto the inner surface 501 of the inner liner 50, which is the inner surface of the tire 1, while rotating the tire 1 around its axis and moving the nozzle 100 in the tire width direction. The nozzle 100 is attached to the tip of an extruder (not shown) and inserted inside the tire 1. The sealant 61 extruded from the extruder is discharged from the tip of the nozzle 100 and applied onto the inner surface of the tire 1. 3, a widthwise cross section of the tire 1 is shown, and the tire width direction X, tire radial direction Y, and tire circumferential direction Z are respectively indicated. In FIG.

[0038] While continuously discharging the sealant material 61 from the nozzle 100 and continuously rotating the tire 1 around its axis, the tire 1 is rotated approximately one revolution while the movement in the tire width direction is stopped, thereby coating one circumferential portion 62. Next, the nozzle 100 is moved to one side in the tire width direction by the width of the sealant material 61, during which the transition portion 63 is coated. Next, the movement in the tire width direction is stopped, and the circumferential portion 62 is coated next to the previously coated circumferential portion 62. By repeating the above operations, the sealant material 61 can be applied in a stepwise manner to the formation region of the sealant layer 60. After the sealant material 61 is applied and attached to the entire formation region of the sealant layer 60, the discharge of the sealant material 61 from the nozzle 100 is stopped. In this manner, the sealant layer 60 is formed from the sealant material 61, and then the sound absorbing layer 70 is disposed on the tire cavity side of the sealant layer 60.

[0039] When the sealant material 61 is applied in steps to the inner surface 501 of the inner liner 50 as described above, as shown in Fig. 2, among the multiple winding portions 62, an initial winding portion 62A on one end side in the tire width direction (left side in Fig. 2) formed first has a first winding overlap portion 62A1 that overlaps in the tire thickness direction with a transition portion 63 from the initial winding portion 62A to the adjacent winding portion 62. Also, a final winding portion 62B on the other end side in the tire width direction (right side in Fig. 2) formed last has a second winding overlap portion 62B1 that overlaps in the tire thickness direction with the transition portion 63 that transitions to the final winding portion 62B. The first surrounding overlapping portion 62A1 is a portion where the transition portion 63 overlaps the attachment starting end portion 61A. The second surrounding overlapping portion 62B1 is a portion where the attachment ending end portion 61B overlaps the transition portion 63.

[0040] The sound absorbing layer 70 is composed of a sound absorbing material 71 made of a foam material such as a sponge. The sound absorbing material 71 is an open-cell foam with many pores and is breathable to the outside air. An example of such a material is soft urethane foam.

[0041] The sound absorbing layer 70 includes at least one sheet-like sound absorbing material 71 wound in a ring shape and attached to the inner surface 601 of the sealant layer 60. As shown in Fig. 2, the sound absorbing material 71 has a joint portion 71A where opposing circumferential ends are joined to each other. The sound absorbing layer 70 may be configured by arranging two or more sound absorbing materials 71 in a connected ring shape.

[0042] The characteristics of the sound absorbing material 71 are a density of 60 kg / m from the viewpoint of weight balance in a pneumatic tire. 3 The following is preferred: density 40 kg / m 3 The following are more preferable: From the viewpoint of durability, the sound absorbing material 71 preferably has a tensile strength of 30 kPa or more and a tear strength of 2.0 N / cm or more (JIS K 6400-5).

[0043] The dimension 70W of the sound absorbing layer 70 in the tire width direction is preferably 90% or more and 100% or less of the dimension 60W of the sealant layer 60 in the tire width direction. The sound absorbing layer 70 is preferably disposed so as to fit within the sealant layer 60 in the tire width direction. Furthermore, each of both ends 702 in the tire width direction of the sound absorbing layer 70 is preferably located further inward in the tire radial direction than the first circumferential overlap portion 62A1 and the second circumferential overlap portion 62B1 of the sealant layer 60, and does not overlap each other.

[0044] It is also preferable that the position of the joint 71A of the sound absorbing layer 70 and the positions of the first circumferential overlap portion 62A1 and the second circumferential overlap portion 62B1 of the sealant layer 60 are shifted in the tire circumferential direction and do not overlap each other.

[0045] According to the tire 1 of the above-described embodiment, if a hole is formed in the tread 30 by, for example, a nail or the like penetrating the tread 30 and reaching the sealant layer 60, the hole is automatically sealed by the sealant layer 60, thereby preventing a puncture. In addition, the sound absorbing layer 70 absorbs and reduces road noise during driving.

[0046] The tire 1 of the present embodiment described above provides the following advantages.

[0047] (1) The tire 1 according to this embodiment includes a pair of beads 10, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 disposed between the pair of sidewalls 20, a carcass ply 40 disposed between the pair of beads 10, an inner liner 50 disposed on the tire cavity side of the carcass ply 40, a sealant layer 60 disposed on at least an inner surface 501 of the inner liner 50 on the tire cavity side corresponding to the tread 30, and a sealant layer 60. and a sound absorbing layer 70 arranged on the tire cavity side. The sealant layer 60 is formed of a strip-shaped sealant material 61 wrapped around and attached to the inner surface 501 of the inner liner 50. The sealant layer 60 has a plurality of annular circumferential portions 62 parallel to the tire circumferential direction in which the sealant materials 61 are arranged in parallel adjacent to each other in the tire width direction, and a plurality of transition portions 63 provided on parts of the circumferential portions 62 in the tire circumferential direction, at which the sealant material 61 transitions to the adjacent circumferential portion 62 on one side in the tire width direction.

[0048] As a result, in the sealant layer 60, the overlapping area of ​​the sealant material 61 is significantly reduced compared to the conventional spirally wound case, thereby suppressing variation in thickness and reducing unevenness, thereby improving adhesion of the sound-absorbing layer 70 to the sealant layer 60.

[0049] 4 shows an example in which the sealant 61 is applied in a spiral shape. According to this, in the first winding 82A along the tire circumferential direction at the left end in the tire width direction in the figure, and in the last winding 82B along the tire circumferential direction at the right end in the tire width direction in the figure, there is a long region in the circumferential direction where adjacent spirally wound sealant materials 61 overlap (shown by the hatched region in the figure). If the overlapping region of the sealant 61 is large in this way, there will be problems such as a large variation in the thickness of the sealant layer and a decrease in adhesion of the sound absorbing layer to the sealant layer. In contrast, in this embodiment, the sealant material 61 is not wound in a spiral manner, but is instead applied in a step manner in which the winding portions 62 parallel to the tire circumferential direction are aligned in the tire width direction, thereby significantly reducing the overlapping area of ​​the sealant material 61 as described above.

[0050] (2) In tire 1 according to this embodiment, the dimension of the sound absorbing layer 70 in the tire width direction is 90% or more and 100% or less of the dimension of the sealant layer 60 in the tire width direction, and the sound absorbing layer 70 is positioned so as to fit within the sealant layer 60 in the tire width direction.

[0051] This makes it possible to reduce the area of ​​the portion of the sealant layer 60 that is not covered by the sound absorbing layer 70, and to prevent foreign matter from adhering to the adhesive sealant layer 60. Furthermore, since the ends of the sound absorbing layer 70 in the tire width direction are attached to the sealant layer 60, the sound absorbing layer 70 is less likely to peel off from the sealant layer 60, and sound absorbing performance is maintained.

[0052] (3) In the tire 1 according to this embodiment, among the multiple winding portions 62 of the sealant layer 60, the first winding portion 62A at one end in the tire width direction and the last winding portion 62B at the other end in the tire width direction have a first winding overlap portion 62A1 and a second winding overlap portion 62B1 that overlap the transition portion 63 in the tire thickness direction, and the sound absorbing layer 70 is formed of a sound absorbing material 71 that is wrapped around the inner surface 601 of the sealant layer 60 along the tire circumferential direction and has a joint portion 71A at which opposing circumferential end portions are joined, and the joint portion 71A of the sound absorbing layer 70 is positioned differently from the first winding overlap portion 62A1 and the second winding overlap portion 62B1 of the sealant layer 60 in the tire circumferential direction.

[0053] As a result, the joint 71A of the sound absorbing layer 70 does not overlap with the first circumferential overlap portion 62A1 and the second circumferential overlap portion 62B1 of the sealant layer 60, making the joint 71A of the sound absorbing layer 70 less likely to peel off from the sealant layer 60, and ensuring adhesion of the sound absorbing layer 70 to the sealant layer 60.

[0054] (4) In the tire 1 according to this embodiment, of the multiple circumferential portions 62 of the sealant layer 60, the first circumferential portion 62A at one end in the tire width direction and the last circumferential portion 62B at the other end in the tire width direction have a first circumferential overlap portion 62A1 and a second circumferential overlap portion 62B1 that overlap the transition portion 63 in the tire thickness direction, and each of the tire width direction ends 702 of the sound absorbing layer 70 is positioned more inward in the tire width direction than the first circumferential overlap portion 62A1 and the second circumferential overlap portion 62B1 of the sealant layer 60.

[0055] As a result, both ends 702 of the sound-absorbing layer 70 in the tire width direction do not overlap the first circumferential overlap portion 62A1 and the second circumferential overlap portion 62B1 of the sealant layer 60, making the both ends 702 of the sound-absorbing layer 70 in the tire width direction less likely to peel off from the sealant layer 60, and ensuring adhesion of the sound-absorbing layer 70 to the sealant layer 60.

[0056] (5) The manufacturing method of a pneumatic tire according to the present embodiment is a manufacturing method of a pneumatic tire in which a sealant layer 60 is formed on an inner surface 501 of an inner liner 50, which is an inner surface of a tire 1, and then a sound absorbing layer 70 is disposed on the tire cavity side of the sealant layer 60. In forming the sealant layer 60, a sealant material 61 is discharged from a nozzle 100 disposed on the inner cavity side of the tire 1 onto the inner surface of the tire 1 while the tire 1 is continuously rotated about its axis, to form a ring-shaped circumferential portion 62 made of the sealant material 61 parallel to the tire circumferential direction. Next, while discharging the sealant material 61 from the nozzle 100, the nozzle 100 is moved relative to the tire 1 in the tire width direction, and then the sealant material 61 is discharged from the nozzle 100 onto the inner surface of the tire 1, thereby forming a next circumferential portion 62 made of the sealant material 61 adjacent to the circumferential portion 62 on one side of the circumferential portion 62 in the tire width direction, by repeating the operation, and a sealant layer 60 in which a plurality of circumferential portions 62 are arranged side by side in the tire width direction is formed on the inner surface of the tire 1.

[0057] As a result, in the sealant layer 60, the overlapping area of ​​the sealant material 61 is significantly reduced compared to the conventional spirally wound case, thereby suppressing variation in thickness and reducing unevenness, thereby improving adhesion of the sound-absorbing layer 70 to the sealant layer 60.

[0058] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and even if modifications and improvements are made within the scope of the present invention, they will still be included in the scope of the present invention. For example, the multiple wrapped portions 62 of the sealant layer 60 are formed by attaching the sealant material 61 in one turn, but the sealant material 61 may be wrapped in multiple turns to obtain a predetermined thickness. Further, the sound absorbing material 71 forming the sound absorbing layer 70 may be formed by joining a plurality of pieces separated in the tire radial direction. When applying the sealant material 61 in steps to form multiple circumferential portions 62, instead of moving the nozzle 100 in the tire width direction, the tire 1 may be moved in the tire width direction, or both the tire 1 and the nozzle 131 may be moved in the tire width direction. [Explanation of symbols]

[0059] 1. Tires (pneumatic tires) 10 Beads 20 Sidewall 30 Tread 40 Carcass ply 50 Inner Liner 60 Sealant Layer 61 Sealant 62 Orbital Division 62A First lap section 62A1 First circular overlapping portion 62B Last lap 62B1 Second orbital overlapping section 63 Transition 70 Sound absorbing layer 71A Joint

Claims

1. A pair of beads; a pair of sidewalls extending radially outward from each of the pair of beads; a tread disposed between the pair of sidewalls; a carcass ply disposed between the pair of beads; An inner liner disposed on the tire cavity side of the carcass ply; a sealant layer disposed on at least the inner surface of the inner liner on the tire cavity side corresponding to the tread; a sound absorbing layer disposed on the tire cavity side of the sealant layer, the sealant layer is formed of a strip-shaped sealant material that is wrapped around and attached to the inner surface of the inner liner, The sealant layer includes a plurality of annular circumferential portions parallel to a tire circumferential direction, the sealant material being arranged in parallel to each other in a tire width direction, the plurality of annular circumferential portions being parallel to each other in a tire width direction, a plurality of transition portions provided in a portion of the circumferential portion in the tire circumferential direction, through which the sealant material transitions to the circumferential portion adjacent to one side in the tire width direction; Among the plurality of winding portions, a first winding portion at one end in the tire width direction and a last winding portion at the other end in the tire width direction each have a winding overlap portion that overlaps the transition portion in the tire thickness direction, the sound absorbing layer is formed of a sound absorbing material that is wound around an inner surface of the sealant layer along a tire circumferential direction and has a joint portion where opposing circumferential end portions are joined to each other, The pneumatic tire comprises a tire circumferential direction, and the joint portion and the circumferential overlap portion are positioned at different positions in the tire circumferential direction.

2. 2. The pneumatic tire according to claim 1, wherein a dimension of the sound absorbing layer in the tire width direction is 90% or more and 100% or less of a dimension of the sealant layer in the tire width direction, and the sound absorbing layer is disposed so as to be contained within the sealant layer in the tire width direction.

3. A pneumatic tire as described in claim 1 or 2, wherein both ends of the sound-absorbing layer in the tire width direction are located more inward in the tire width direction than the circumferential overlap portion.

4. A method for manufacturing a pneumatic tire, comprising forming a sealant layer on an inner surface of a tire, and then disposing a sound absorbing layer on a tire cavity side of the sealant layer, comprising: In forming the sealant layer, the tire is continuously rotated around its axis, A sealant material is discharged onto an inner surface of the tire from a nozzle disposed on an inner cavity side of the tire, a sealant layer is formed on the inner surface of the tire in which a plurality of the circumferential portions are arranged in parallel in the tire width direction, and the nozzle is then moved relative to the tire in the tire width direction while discharging the sealant material from the nozzle, thereby forming a next circumferential portion of the sealant material adjacent to the circumferential portion on one side of the circumferential portion in the tire width direction, and a transition portion is formed in a portion of the circumferential portion in the tire circumferential direction, in which the sealant material transitions to the circumferential portion adjacent to the one side in the tire width direction, by repeating the above steps; The sound absorbing layer is formed from a sound absorbing material that is wound around an inner surface of the sealant layer in a tire circumferential direction and has a joint portion where opposing circumferential ends are joined to each other, Among the plurality of winding portions, a first winding portion at one end in the tire width direction and a last winding portion at the other end in the tire width direction each have a winding overlap portion that overlaps the transition portion in the tire thickness direction, The method for manufacturing a pneumatic tire, wherein the joint portion and the circumferential overlap portion are positioned at different positions in the tire circumferential direction.

Images