JP7612401B2 - Pneumatic tire and method of manufacturing same - Google Patents

Description

The present invention relates to a pneumatic tire for a vehicle and a method for manufacturing the same.

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 the sealant layer has a two-layer structure, and each sealant layer has a sealant material arranged in a spiral shape and the sealant materials are arranged so as to be shifted from each other in the tire width direction.

JP 2019-23027 A

Normally, the sealant layer is disposed so as to cover the entire inner surface of the tire in the area corresponding to the tire tread. As a result, the inner surface of the tire covered with the sealant layer accumulates heat, and the tire may deteriorate due to the effects of that heat. This problem is more pronounced when the sealant layer has a two-layer structure as in Patent Document 1, and there is therefore room for improvement.

The present invention was made in consideration of the above circumstances, and aims to provide a pneumatic tire and a manufacturing method thereof that can suppress the decrease in tire durability caused by heat accumulation in the sealant layer while maintaining the puncture prevention function of the sealant layer.

The pneumatic tire of the present invention comprises 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 and having a ground contact surface, a carcass ply stretched between the pair of beads, an inner liner disposed on the tire cavity side of the carcass ply, and a sealant layer disposed on the inner surface of the tire cavity side of the inner liner, the ground contact surface of the tread is formed with a plurality of grooves extending in the tire circumferential direction, the sealant layer has a plurality of circumferential portions provided in a band shape in annular portions corresponding to each of the plurality of grooves on the inner surface of the inner liner, and the plurality of circumferential portions are spaced apart from each other in the tire width direction.

The method for manufacturing a pneumatic tire of the present invention involves rotating a tire having at least one groove formed on the contact surface of the tread that extends in the tire circumferential direction, while discharging and applying a sealant material from a nozzle disposed on the tire cavity side onto the tire inner surface to form a sealant layer on the tire inner surface. Groove position information indicating the position of the groove is obtained, and based on the obtained groove position information, the nozzle is moved relative to the tire in the tire width direction to apply the sealant material to the annular portion of the tire inner surface that corresponds to the groove.

The present invention provides a pneumatic tire and a manufacturing method thereof that can suppress the decrease in tire durability caused by heat accumulation in the sealant layer while maintaining the puncture prevention function of the sealant layer.

1 is a cross-sectional view in the tire width direction of a tire according to an embodiment of the present invention. FIG. 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 in schematic form. FIG. 2 is a schematic diagram showing a state in which a sealant material is applied to an inner surface of a tire by a nozzle of an application device for implementing a tire manufacturing method according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a coating device capable of suitably carrying out a tire manufacturing method according to an embodiment of the present invention.

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.

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 the tire 1 mounted on a specified rim and inflated to a specified internal pressure in an unloaded state. Note that the specified rim refers to the standard rim determined by JATMA for the tire size. The specified internal pressure is, for example, 180 kPa when the tire is for a passenger car.

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 a direction approaching the tire equatorial plane S1, and corresponds to the center side of the paper in Fig. 1. The outer side in the tire width direction is a direction away from the tire equatorial plane S1, and corresponds to 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 a direction away from the tire rotation axis, and is the lower side in Fig. 1. The inner side in the tire radial direction is a direction approaching the tire rotation axis, and is the upper side in Fig. 1.

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.

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

The bead core 11 is an annular component formed by winding a rubber-coated metal bead wire multiple times, and serves to fix the tire 1 filled with air to the 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, for example, rubber that is harder than the surrounding rubber members.

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.

The sidewall 20 includes a sidewall rubber 21 arranged 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 part that bends the most when the tire 1 acts as a cushion, and typically uses flexible rubber that is fatigue resistant.

The tread 30 comprises an endless belt 31, a cap ply 32, and a tread rubber 33.

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 in 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.

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 multiple 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.

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 contact surface 331 that comes into contact with the road surface during driving. The contact surface 331 of the tread rubber 33 is provided with a tread pattern 34 that is composed of, for example, a number of grooves. The tread pattern 34 has a number of main grooves 341 aligned in the tire width direction. Each of the main grooves 341 extends along the tire circumferential direction. The main grooves 341 are an example of a groove.

In this embodiment, four main grooves 341 are formed in the ground contact surface 331. The four main grooves 341 are arranged symmetrically with respect to the center of the ground contact surface 331 in the tire width direction.
It should be noted that there is no limitation to the number and arrangement of the main grooves 341. For example, the main grooves 341 may be arranged asymmetrically rather than symmetrically about the center in the tire width direction.

In the ground contact surface 331 of the tread 30, multiple central land portions 342 are arranged between multiple main grooves 341. Each of the multiple central land portions 342 extends in the tire circumferential direction. In addition, the ground contact surface 331 of the tread 30 has side land portions 343 that have a tire thickness similar to that of the central land portions 342 in the tire width direction outer portions of the two main grooves 341 arranged on the outermost sides in the tire width direction.

The carcass ply 40 constitutes a ply that forms 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.

The carcass ply 40 has a ply body 401 that extends from one bead core 11 to the other bead core 11 and extends between the tread 30 and the bead 10, a pair of bends 402 that are folded back from the ply body 401 at the bead core 11, and a pair of turn-up portions 403 that extend radially outward from each of the bends 402. The ply body 401, the bends 402, and the turn-up portions 403 are continuous.

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 folded-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 folded-up portion 403 is overlapped with the ply body portion 401. The bent portion 402 constitutes the innermost portion in the tire radial direction of the carcass ply 40.

In this embodiment, the carcass ply 40 has a single layer structure, but the carcass ply 40 is not limited to a single layer structure and may have a two-layer, three-layer or more layer structure.

The chafer 13 of the bead 10 described above is arranged to surround the radially inner end of the carcass ply 40 including the bend 402. The rim strip rubber 14 is arranged on the outer side in the tire width direction of the chafer 13 and the folded-back portion 403 of the carcass ply 40. The radially outer end of the rim strip rubber 14 is covered with the sidewall rubber 21 described above.

The inner liner 50 covers the inner surface of the tire between the 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.

As shown in FIG. 1, the tire 1 according to this embodiment further includes a sealant layer 60.

As shown in FIG. 1, the sealant layer 60 is provided on the inner surface 501 of the inner liner 50, which is the inner surface of the tire. In this embodiment, the sealant layer 60 includes a circumferential portion 62 provided in a band shape in an annular portion corresponding to each of the multiple main grooves 341 provided in the ground contact surface 331 of the tread 30. The sealant layer 60 is attached to the inner surface 501 of the inner liner 50 by its own adhesiveness.

Figure 2 is a development view showing the inner surface of the tire 1, and shows a schematic of the sealant layer 60 provided on the inner surface of the tire 1. In Figure 2, the arrow X indicates the tire width direction, and the arrow Z indicates the tire circumferential direction.

As shown in FIG. 2, the sealant layer 60 is formed of a strip of sealant material 61 that is attached to the inner surface 501 of the inner liner 50 while being wrapped around the tire circumferential direction. The sealant layer 60 has multiple annular circumferential portions 62 and multiple transition portions 63 formed by the sealant material 61.

In FIG. 2, reference numeral 61A indicates the application start end of the sealant material 61, and reference numeral 61B indicates the application end end of the sealant material 61. As shown in FIG. 2, the sealant material 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.

The circumferential portion 62 is formed by attaching the sealant material 61 to the inner surface 501 of the inner liner 50 in parallel with the tire circumferential direction. The sealant material 61 is attached to the inner surface 501 of the inner liner 50 once or multiple times to form a band-shaped circumferential portion 62.

The multiple circumferential portions 62 are arranged in parallel at intervals in the tire width direction. Each of the multiple circumferential portions 62 is provided in a band shape in annular portions on the inner surface 501 of the inner liner 50 corresponding to each of the multiple main grooves 341. As a result, the multiple circumferential portions 62 are spaced apart from each other in the tire width direction. In other words, each of the multiple circumferential portions 62 is arranged on the tire radial inner side of the multiple main grooves 341. In this embodiment, since there are four main grooves 341, four circumferential portions 62 are formed.
The width of each of the plurality of circumferential portions 62 is equal to or greater than the width of the corresponding main groove 341. It is preferable that each of the plurality of circumferential portions 62 covers the corresponding main groove 341 in the tire width 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 approximately once or multiple times to form one circumferential portion 62. That is, the transition portion 63 is formed between a pair of circumferential portions 62 adjacent to each other in the tire width direction. After passing through the transition portion 63, the next circumferential portion 62 is attached to one side in the tire width direction of the circumferential portion 62 with a gap therebetween. The gap between the pair of adjacent circumferential portions 62 corresponds to the central land portion 342. After passing through the transition portion 63, the next circumferential portion 62 adjacent to one side in the tire width direction is repeatedly formed to provide the sealant layer 60.

Each of the transition portions 63 extends linearly and is inclined at a predetermined angle with respect to the tire circumferential direction. In this embodiment, since there are four main grooves 341, a total of three transition portions 63 are provided, one between each of the circumferential portions 62. As shown in Fig. 2, in this embodiment, the three transition portions 63 are arranged in a substantially straight line overall while being offset in the tire circumferential direction.
The multiple transition portions 63 may be arranged in parallel in the tire width direction, but the arrangement is not limited thereto.

In this manner, when the sealant material 61 is applied to the inner surface of the tire, the circumferential portion 62, which is parallel to the tire circumferential direction, is applied in sequence in the tire width direction, passing through the transition portion 63. This method of application may be referred to as step application below.

For example, the sealant material 61 may be 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. However, the sealant material 61 is not limited to this, and may be any other known sealing material that has been used conventionally.

To apply the sealant 61 in a stepwise manner, as shown in FIG. 3 , the tire 1 is rotated around its axis while the nozzle 131 is moved in the tire width direction, and the sealant 61 is ejected from the nozzle 131 and applied to the inner surface 501 of the inner liner 50, which is the inner surface of the tire 1.
3 shows a widthwise cross section of the tire 1, and indicates the tire width direction X, the tire radial direction Y, and the tire circumferential direction Z. In FIG. 3, the symbol G indicates the rotation axis of the tire 1.

When applying the sealant 61 to the inner surface of the tire 1 in a stepwise manner as shown in FIG. 3, a sealant application device 100 shown in FIG. 4 can be used.

Figure 4 shows the schematic configuration of the sealant application device 100, which includes a tire rotation mechanism 110, a nozzle slide mechanism 120, a sealant discharge mechanism 130, and a control unit 140.

The tire rotating mechanism 110 is a mechanism for rotating the tire 1 after vulcanization molding and before the sealant layer 60 is formed, around an axis as shown in FIG.
The nozzle slide mechanism 120 is a mechanism that moves the nozzle 131 in the tire width direction relative to the tire 1 set on the tire rotation mechanism 110.

The sealant material discharge mechanism 130 has the nozzle 131 and an extruder (not shown) to which the nozzle 131 is attached at its tip. The nozzle 131 is inserted inside the tire 1 set in the tire rotation mechanism 110. The sealant material discharge mechanism 130 applies the sealant material 61 extruded from the extruder by discharging it from the tip of the nozzle 131 onto the inner surface of the tire 1.

Groove position information is input to the control unit 140. The control unit 140 controls the operation of each of the tire rotation mechanism 110, the nozzle slide mechanism 120, and the sealant material discharge mechanism 130 based on the input groove position information.

In this embodiment, the groove position information includes coordinates indicating the positions in the tire width direction, widths, and widths of the central land portions 342 between the main grooves 341 formed in the tread 30 of the tire 1, and the circumferential length of the inner surface 501 of the inner liner 50 to which the sealant 61 is applied. Such groove position information can be obtained, for example, based on CAD data at the time of tire design.
The coordinates of the main grooves 341 in the tire width direction can also be obtained by scanning and reading the contact surface 331 of the tread 30 of the vulcanized tire 1 with a laser beam.
The method for acquiring the groove position information is not limited to these, and other appropriate methods may be used.

The control unit 140 receives the groove position information, grasps the groove position information, and controls the operation of the tire rotation mechanism 110, nozzle slide mechanism 120, and sealant material discharge mechanism 130.

The sealant application device 100 operates as follows to apply the sealant 61 in steps to the inner surface of the tire 1. This operation is an example of a specific operation of the tire manufacturing method according to this embodiment.

While continuously discharging the sealant material 61 from the nozzle 131 and rotating the tire 1 around its axis, the nozzle 131 is stopped moving in the tire width direction while rotating the tire 1, thereby coating the first circumferential portion 62 on one end side in the tire width direction. Next, the nozzle 131 is moved to one side in the tire width direction to position the nozzle 131 at the formation position of the next circumferential portion 62. During this movement, the transition portion 63 is coated. Next, the nozzle 131 is stopped moving in the tire width direction to coat the circumferential portion 62. By repeating the above operation, the sealant material 61 is applied in steps. When a predetermined number of circumferential portions 62 (four in this embodiment) are formed by the sealant material 61, the discharge of the sealant material 61 from the nozzle 131 is stopped.

The control unit 140 controls the sliding movement of the nozzle 131 in the tire width direction by the nozzle slide mechanism 120 so that the sealant material 61 is applied to the multiple main grooves 341 based on the coordinates of the multiple main grooves 341 in the tire width direction. The control unit 140 also controls the circumferential portion 62 extending in the tire circumferential direction so that the sealant material 61 is applied to the entire circumference of the inner surface 501 based on the circumferential length of the inner surface 501 of the inner liner 50. One circumferential portion 62 is formed by applying the sealant material 61 around one circumference. Alternatively, one circumferential portion 62 is formed by applying the sealant material 61 around multiple circumferences by moving the tire 1 slightly in the tire width direction multiple times.

According to the tire 1 of the above-mentioned embodiment, when a puncture inducer such as a nail or tack penetrates through the main groove 341, the tire thickness is smaller and therefore the resistance when penetrating is smaller, making it more likely for the puncture inducer to reach the tire cavity and cause a puncture than when the puncture inducer penetrates the central land portion 342 or the side land portion 343 between the main grooves 341. Conversely, the central land portion 342 and the side land portion 343 are thicker, so the resistance when the puncture inducer penetrates is greater, making it less likely for the puncture inducer to cause a puncture even if the puncture inducer penetrates the central land portion 342 or the side land portion 343.

In the tire 1 according to this embodiment, the circumferential portion 62 of the sealant layer 60 is formed in a band shape on the inner surface 501 of the inner liner 50 on the tire cavity side of the main groove 341, corresponding to the main groove 341, which is a part that is prone to puncture as described above. Therefore, if a hole that reaches the circumferential portion 62 is caused by a puncture-inducing substance that has passed through the main groove 341, the hole is automatically blocked by the circumferential portion 62, and a puncture is prevented from occurring. Therefore, the sealant layer 60 has a high probability of preventing punctures, and the puncture prevention function is maintained. The thickness of the circumferential portion 62 that prevents punctures is preferably, for example, about 1 mm or more and 10 mm or less.

In this embodiment, the sealant layer 60 is provided in a strip shape on the inner surface 501 of the inner liner 50 on the tire cavity side of each main groove 341, corresponding to the multiple main grooves 341, and does not cover the entire surface of the tire inner surface in the area corresponding to the tread 30. That is, in this embodiment, the multiple circumferential portions 62 arranged corresponding to each main groove 341 provide a puncture prevention function. Because the sealant layer 60 has a structure having multiple circumferential portions 62 distributed in the tire width direction, the sealant layer 60 suppresses heat accumulation in the tire 1, and as a result, the decrease in tire durability caused by the heat accumulation is suppressed.

In addition, the tire manufacturing method according to this embodiment using the above-mentioned sealant application device 100 can suitably form the tire 1 of this embodiment having the sealant layer 60.

The above-described embodiment provides the following advantages:

(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 disposed between the pair of sidewalls 20 and having a ground contact surface 331, a carcass ply 40 stretched between the pair of beads 10, an inner liner 50 disposed on the tire cavity side of the carcass ply 40, and a sealant layer 60 disposed on the inner surface of the tire cavity side of the inner liner 50. The ground contact surface 331 of the tread 30 has a plurality of main grooves 341 extending in the tire circumferential direction, and the sealant layer 60 has a plurality of circumferential portions 62 arranged in a band shape in annular portions corresponding to each of the plurality of main grooves 341 on the inner surface 501 of the inner liner 50, and each of the plurality of circumferential portions 62 is spaced apart from each other in the tire width direction.

This allows the puncture prevention function of the sealant layer 60 to be maintained while suppressing the decrease in tire durability caused by heat accumulation in the sealant layer 60.

(2) In the tire 1 according to this embodiment, the sealant layer 60 is formed of a strip-shaped sealant material 61 that is wrapped around and attached to the inner surface 501 of the inner liner 50, and the multiple circumferential portions 62 are formed by attaching the sealant material 61 to annular portions corresponding to the multiple main grooves 341, and a transition portion 63 is formed between a pair of circumferential portions 62 adjacent to each other in the tire width direction, where the sealant material 61 transitions from one of the pair of circumferential portions 62 to the other.

As a result, a sealant layer 60 extending in the tire circumferential direction corresponding to each of the multiple main grooves 341 is accurately formed on the inner surface 501 of the inner liner 50. The multiple circumferential portions 62 formed corresponding to each of the multiple main grooves 341 are spaced apart from each other corresponding to the spacing between the multiple main grooves 341. Furthermore, the sealant layer 60 is not disposed in the portions corresponding to the central land portion 342 and the side land portion 343, which are prone to heat accumulation. As a result, heat accumulation in the tire 1 is suppressed, and a decrease in tire durability is suppressed.

(3) In the tire 1 according to this embodiment, the width of the circumferential portion 62 of the sealant layer 60 is equal to or greater than the width of the main groove 341, and the circumferential portion 62 includes a configuration in which the circumferential portion 62 covers the main groove 341 in the tire width direction.

As a result, puncture-inducing objects such as nails and rivets passing through the main groove 341 reliably penetrate the circumferential portion 62 of the sealant layer 60, so that the sealant layer 60 can prevent punctures caused by puncture-inducing objects passing through the main groove 341.

(4) In the tire 1 according to this embodiment, the circumferential portion 62 of the sealant layer 60 includes a configuration in which the sealant material 61 is wrapped around the tire circumferential direction multiple times.

This allows the width of the circumferential portion 62 to be adjusted according to the tire width dimension of the main groove 341.

(5) In the method for manufacturing a pneumatic tire according to this embodiment, a tire 1 having at least one main groove 341 extending in the tire circumferential direction on the contact surface 331 of the tread 30 is rotated about an axis while a sealant material 61 is ejected from a nozzle 131 disposed on the tire cavity side and applied to the inner surface of the tire to form a sealant layer 60 on the inner surface of the tire. Groove position information indicating the position of the main groove 341 is obtained, and based on the obtained groove position information, the nozzle 131 is moved relative to the tire 1 in the tire width direction to apply the sealant material 61 to the annular portion of the inner surface of the tire corresponding to the main groove 341.

This makes it possible to manufacture a tire that maintains the puncture prevention function of the sealant layer 60 while suppressing the decrease in tire durability caused by heat accumulation in the sealant layer 60.

(6) In the manufacturing method of a pneumatic tire according to this embodiment, it is preferable that the groove position information includes the coordinates of the main groove 341 in the tire width direction and the circumferential length of the inner surface of the tire to which the sealant material 61 is applied.

This allows the sealant layer 60 to be accurately formed with dimensions that correspond to the tire width and circumferential lengths of the main groove 341.

(7) In the manufacturing method of a pneumatic tire according to this embodiment, the tire 1 has a plurality of main grooves 341, and includes a form in which the sealant material 61 is applied to the inner surface of the tire in correspondence with the plurality of main grooves 341.

This allows the sealant layer 60, which extends in the tire circumferential direction and corresponds to the multiple main grooves 341, to be accurately formed on the inner surface 501 of the inner liner 50.

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, in the above embodiment, the main grooves 341 are arranged symmetrically with respect to the center of the tire width direction of the ground contact surface 331, but the main grooves 341 may be arranged asymmetrically instead of symmetrically with respect to the center of the tire width direction. The circumferential portion 62 of the sealant layer 60 is arranged on the inner surface 501 of the inner liner 50 in correspondence with the asymmetric main grooves 341.

In the tire manufacturing method of the above embodiment, one strip of sealant 61 is continuously applied from the application start end 61A to the application end end 61B so as to have a transition portion 63 between multiple circumferential portions 62. However, the sealant 61 may be applied intermittently so as to apply and form only the multiple circumferential portions 62, without forming the transition portion 63.
In addition, when applying paint to multiple circumferential portions 62, instead of moving the nozzle 131 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.

1. Tires (pneumatic tires)
REFERENCE SIGNS LIST 10 Bead 20 Sidewall 30 Tread 40 Carcass ply 50 Inner liner 60 Sealant layer 61 Sealant material 62 Circumferential portion 63 Transition portion 131 Nozzle 331 Ground contact surface 341 Main groove (groove)
501 Inner surface of inner liner (inner surface of tire)

Claims (6)

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 and having a ground contact surface;
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 an inner surface of the inner liner on the tire cavity side,
A plurality of grooves extending in a tire circumferential direction are formed on the ground contact surface of the tread,
the sealant layer has a plurality of circumferential portions provided in a band shape in annular portions corresponding to the plurality of grooves on the inner surface of the inner liner, the plurality of circumferential portions being spaced apart from one another in the tire width direction,
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 plurality of circumferential portions are formed by attaching the sealant to annular portions corresponding to the plurality of grooves,
A pneumatic tire , wherein a transition portion is formed between a pair of the circumferential portions adjacent to each other in the tire width direction, through which the sealant material transitions from one of the pair of the circumferential portions to the other of the pair of the circumferential portions. The width of the circumferential portion is equal to or greater than the width of the groove,
The pneumatic tire according to claim 1 , wherein the circumferential portion covers the groove in a tire width direction. The pneumatic tire according to claim 1 , wherein the circumferential portion is formed by wrapping the sealant material around the tire circumferential direction a plurality of times. A tire having a plurality of grooves formed in a contact surface of a tread and extending in a tire circumferential direction is rotated around an axis, and a sealant material is discharged from a nozzle disposed on the tire cavity side onto the tire inner surface to apply the sealant material thereto, thereby forming a sealant layer on the tire inner surface,
obtaining groove position information indicating the position of the groove;
Based on the groove position information thus obtained, the nozzle is moved relative to the tire in a tire width direction, thereby applying the sealant to an annular portion of the tire inner surface corresponding to the groove ;
a sealant material applied to the annular portions while forming a transition portion between the annular portions by the sealant material when the nozzle is moved relative to the tire in a tire width direction . The method for manufacturing a pneumatic tire according to claim 4 , wherein the groove position information includes a coordinate of the groove in a tire width direction and a circumferential length of the inner surface of the tire to which the sealant is applied. The method for manufacturing a pneumatic tire according to claim 4 or 5 , wherein the tire has a plurality of the grooves, and the sealant material is applied to the tire inner surface corresponding to the plurality of the grooves.

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