JP2024014334A - Pneumatic tire manufacturing method and manufacturing equipment - Google Patents

Abstract

The present invention provides a pneumatic tire manufacturing method and a pneumatic tire manufacturing apparatus that can reduce unevenness of a sealant layer formed on the tire. [Solution] A method of manufacturing a pneumatic tire involves rotating a nozzle facing the inner surface of the tire relatively around the axis of the tire, and applying a band-shaped sealant material discharged from the outlet of the nozzle to the inner surface of the tire. coating to form a sealant layer on the inner surface of the tire. The discharge port has a first side located on the front side in the nozzle traveling direction and a second side located on the rear side in the nozzle traveling direction. At least one of the first side and the second side has a constriction that projects inside the discharge port. [Selection diagram] Figure 5

Description

The present disclosure relates to a method and apparatus for manufacturing a pneumatic tire.

As a pneumatic tire with a puncture prevention function, a pneumatic tire (also referred to as a sealant tire) that includes a sealant layer formed by applying a sealant material to the inner surface of the tire is known. In a sealant tire, the through hole that is formed when the tire is punctured is automatically closed by the sealant material, thereby preventing air from leaking from the tire.

Patent Document 1 discloses that a sealant material is applied spirally to the inner surface of a tire.
Patent Document 2 discloses that a belt-shaped sealant material applied to the inner surface of a tire is pressed down with a roller until the next sealant material is adhered next to it.

International Publication No. 2016/060236 JP2020-23152A

However, in Patent Document 1, there is a risk that the sealant material discharged from the discharge port of the nozzle may swell in the width direction. In that case, there is a risk that the adjacent sealant material that has already been applied will be pushed up from the side, causing unevenness in the sealant layer formed on the inner surface of the tire.
In Patent Document 2, pressing the sealant material applied with a nozzle with a roller is not a practical technique because the sealant is hot and sticks to the roller, causing the sealant to transfer from the inner surface of the tire to the roller. It's hard to say.

The present disclosure provides a method and apparatus for manufacturing a pneumatic tire that can reduce unevenness of a sealant layer formed on the tire.

In the method for manufacturing a pneumatic tire of the present disclosure, a belt-shaped sealant material discharged from a discharge port of the nozzle is applied to the tire while a nozzle directed toward the inner surface of the tire is rotated relatively around the axis of the tire. forming a sealant layer on the inner surface of the tire by applying the sealant to the inner surface of the tire, and the discharge port is located on a first side located on the front side in the direction of travel of the nozzle and on the rear side in the direction of travel of the nozzle. a second side, and at least one of the first side and the second side has a constriction that projects inside the discharge port.

A tire meridian cross-sectional view showing a tire. FIG. 1 is a configuration diagram of a tire manufacturing apparatus for manufacturing a sealant tire by forming a sealant layer. FIG. 3 is a side view showing a process of applying a sealant material. FIG. 3 is a schematic plan view of a sealant layer for explaining the application structure of a sealant material. The side view and the bottom view of a nozzle which show how the nozzle of a 1st embodiment discharges sealant material. The side view and the bottom view of a nozzle which show how the nozzle of 2nd Embodiment discharges a sealant material. (a) A diagram showing the shape of a sealant layer applied by the nozzle of Comparative Example 1. (b) A diagram showing the shape of a sealant layer applied by the nozzle of the second embodiment shown in FIG. 6. (c) A diagram showing the shape of a sealant layer applied by the nozzle of the first embodiment shown in FIG. 5. (a) and (b) Diagrams showing the cross-sectional shape of the sealant material applied onto the inner surface of the tire by the nozzle of the second embodiment. (c) A diagram showing the cross-sectional shape of the sealant material applied onto the inner surface of the tire by the nozzle of the first embodiment. The figure which shows the bottom view of the nozzle of a modification.

Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings.

The pneumatic tire of this embodiment is a sealant tire that includes a sealant layer formed by applying a band-shaped sealant material to the inner surface of the tire along the circumferential direction of the tire. The tire is a so-called tubeless tire, and is used with the inside filled with gas such as air.

[First embodiment]
FIG. 1 is a tire meridian cross-sectional view showing a tire 1. As shown in FIG. The tire 1 includes an annular tread 2 that is in contact with the road surface, a pair of left and right bead portions 3, 3 located inside the tread 2 in the tire radial direction RD, and left and right bead portions 3, 3 located between the tread 2 and the bead portions 3, 3. A pair of side walls 4, 4 are provided. The tire 1 includes a bead core 5 embedded in a bead portion 3, a carcass ply 6 extending in a toroidal shape between the left and right bead portions 3, a belt 7 provided on the outer peripheral side of the carcass ply 6 in the tread 2, and a tread. It includes rubber 8, an inner liner 9 provided on the inner surface side of the tire of the carcass ply 6, and a sealant layer 10 provided on the inner surface side of the tire of the inner liner 9.

The sealant layer 10 is provided on the inner surface 1A of the tire 1, specifically on the inner side of the inner liner 9. In this example, the sealant layer 10 is provided on the tire inner surface 1A of the tread 2 from one end to the other end in the tire axial direction AD. As described above, the sealant layer 10 is preferably provided over the entire inner surface of the tread 2, and may be provided only on the inner surface of the tread 2, but may be provided over a wider area including the inner surface of the tread 2. That is, the sealant layer 10 is preferably provided on the inner surface 1A of the tire 1 including the inner surface of the tread 2.

Here, the tire radial direction RD refers to a direction perpendicular to the tire rotation axis, the inside of the tire radial direction RD refers to a direction approaching the tire rotation axis, and the outside of the tire radial direction RD refers to a direction away from the tire rotation axis. Refers to direction. The tire axial direction AD is also referred to as the tire width direction, and is a direction parallel to the tire rotation axis. The tire circumferential direction CD (see FIG. 4) is a direction on the circumference centered on the tire rotation axis.

In the tire manufacturing method of the first embodiment, a band-shaped sealant material 11 (see FIG. 4) is displaced from one side in the tire axial direction AD to the other side on the inner surface 1A of the vulcanized tire 1 while moving in the tire circumferential direction CD. The tire 1 including the sealant layer 10 is manufactured by forming the sealant layer 10 by continuously applying the sealant layer 10 along the sealant layer 10 .

The method for manufacturing a vulcanized tire is not particularly limited, and any known method can be employed. That is, a green tire (unvulcanized tire) is manufactured using tire constituent members such as the bead core 5, carcass ply 6, belt 7, and tread rubber 8, and the obtained green tire is vulcanized and molded. You can get a finished tire. After the green tire is vulcanized and molded, the sealant layer 10 is formed using the sealant material 11.

The sealant material 11 is not particularly limited, and any known sealant material can be used. Generally, a sticky rubber material is used as the sealant material. In detail, for example, butyl rubber and/or ethylene propylene diene rubber is used as a rubber component, and liquid rubber, plasticizer, filler, crosslinking agent (organic peroxide), and crosslinking aid (vulcanization accelerator) are added to the rubber component. A rubber composition containing the following may be used, but is not limited thereto. Examples of butyl rubber include butyl rubber and halogenated butyl rubber such as brominated butyl rubber and chlorinated butyl rubber.

FIG. 2 is a configuration diagram of a tire manufacturing apparatus 20 for manufacturing a sealant tire by forming a sealant layer 10, and shows the tire 1 cut away. The tire manufacturing apparatus 20 includes a support device 30 that supports the tire 1, a discharge machine 40 that discharges the sealant material 11, and a control section (not shown) that controls the formation operation of the sealant layer 10 by the support device 30 and the discharge machine 40. Equipped with.

In this example, the support device 30 includes an outer periphery support part 31 that supports the outer periphery of the tire 1 with the tire rotation axis in a horizontal state, and a drive device 32 that rotates the supported tire 1 around the tire rotation axis. However, the present invention is not limited thereto, and for example, the outer periphery support portion may support the outer periphery of the tire by tilting the tire rotation axis with respect to the horizontal direction.

The discharge machine 40 includes a nozzle 41 that discharges the sealant material 11, a supply device 42 that supplies the sealant material 11 to the nozzle 41, and a movement device 43 that moves the nozzle 41.

The supply device 42 is a device that supplies the heated sealant material 11 to the nozzle 41 via the supply pipe 44, and can be configured using, for example, a fixed displacement pump such as a gear pump.

The nozzle 41 is a member that discharges the sealant material 11 supplied from the supply device 42, and has a discharge port 45 at the tip of the nozzle 41 that discharges the sealant material 11, as shown in FIG. The nozzle 41 is a die (die) that discharges the sealant material 11 into a predetermined cross-sectional shape, and the discharge port 45 is an opening formed in the nozzle 41 .

In this example, the moving device 43 is constituted by a multi-axis robot having degrees of freedom in at least three axes, and a nozzle 41 is attached to the tip of its arm 43A. The nozzle 41 is placed inside the tire 1 by the moving device 43, and the discharge port 45 of the nozzle 41 is placed facing downward.

FIG. 5 is a side view and a bottom view of the nozzle 41 showing how the nozzle 41 of the first embodiment discharges the sealant material 11. The moving device 43 moves the nozzle 41 within the tire 1 with the discharge port 45, ie, the bottom surface of the nozzle 41, facing the inner surface 1A of the tire, as shown in FIGS. 3 and 5. As shown in FIG. 5, the discharge port 45 has a flat shape in which a length H1 of the nozzle 41 in the traveling direction TD is shorter than a length W2 of the nozzle 41 in the orthogonal direction DD orthogonal to the traveling direction TD. The discharge port 45 in this example is an opening having an elongated trapezoidal shape. In this embodiment, the lateral direction of the discharge port 45 coincides with the traveling direction TD, and the longitudinal direction of the discharge port 45 perpendicular to the lateral direction TD coincides with the orthogonal direction DD.

As shown in FIG. 5, the discharge port 45 has a first side 51 located on the front side TD1 in the direction of movement of the nozzle 41, a second side 52 located on the rear side TD2 in the direction of movement of the nozzle 41, and a second side 52 located on the rear side TD2 in the direction of movement of the nozzle 41. The third side 53 and the fourth side 54 located on both sides of the orthogonal direction DD perpendicular to the traveling direction, the first corner 55, the second corner 56, the third corner 57, and the fourth corner 58 and has. The first side 51 is a side having a constriction that protrudes further inside the discharge port 45 than a first straight line 51s (virtual straight line) connecting the first corner 55 and the second corner 56. The constriction narrows the opening thickness of the discharge port 45. In the example of FIG. 5, the first side 51 is a single curved line, and the radius of curvature thereof is 8.2 mm, but is not limited thereto. The second side 52 is a side having a constriction that projects further inside the discharge port 45 than a second straight line 52s (virtual straight line) connecting the third corner 57 and the fourth corner 58. The constriction narrows the opening thickness of the discharge port 45. In the example of FIG. 5, the second side 52 is a single curved line, and the radius of curvature thereof is 8.2 mm, but is not limited thereto. The third side 53 is a third straight line 53s that connects the first corner 55 and the third corner 57. The fourth side 54 is a fourth straight line 54s that connects the second corner 56 and the fourth corner 58.
In this embodiment, each corner 55, 56, 57, 58 is bent, but may be slightly rounded.
In this way, the discharge port 45 has a shape based on a quadrilateral including a trapezoid, and each side (first side 51, second side 52, third side 53, and fourth side 54) of the discharge port 45 It does not have a shape that bulges outward. Therefore, swell (expansion) of the sealant material 11 can be suppressed.

As shown in the figure, the length W1 of the first side 51 is shorter than the length W2 of the second side 52 in the orthogonal direction DD. W1 is 4.0 mm, and W2 is 9.0 mm. The length H1 of the discharge port 45 in the traveling direction TD is 3.28 mm. The maximum length W2 of the discharge port 45 in the longitudinal direction DD in this embodiment is 9.0 mm, but is not particularly limited, and may be, for example, 8 to 20 mm. The length H1 of the discharge port 45 in the lateral direction TD is also not particularly limited, and may be, for example, 2 to 5 mm. Moreover, it is preferable that the first corner 55 is located inside the third corner 57 in the orthogonal direction DD. The second corner 56 is preferably located inside the fourth corner 58 in the orthogonal direction DD.

In the first embodiment, the distance D1 between the discharge port 45 and the tire inner surface 1A is set to be less than or equal to the dimension W2 of the discharge port 45 in the longitudinal direction DD, and in this example, D1=W2. As shown in FIG. 3, the moving device 43 moves the nozzle 41 within the tire 1 with the discharge port 45, ie, the bottom surface of the nozzle 41, facing the inner surface 1A of the tire. This makes it easy to define the thickness of the sealant material 11 discharged from the discharge port 45 by the gap between the discharge port 45 and the tire inner surface 1A, regardless of the orientation of the rotating discharge port 45 as described later. , a band-shaped sealant material 11 having a thickness corresponding to the distance D1 can be formed on the tire inner surface 1A.

When forming the sealant material 11 having a thickness corresponding to the distance D1 on the tire inner surface 1A in this way, it is preferable to control the amount of discharge from the nozzle 41 using, for example, a gear pump. Specifically, the thickness of the sealant material 11 formed on the tire inner surface 1A corresponds to the distance D1, and the width of the sealant material 11 corresponds to the length W2 of the discharge port 45 in the longitudinal direction DD. (mm)", "Length W2 (mm)", and "Rotational speed of the inner surface of the tire 1A with respect to the nozzle 41 (i.e., the relative speed of both) (mm/sec)", the product of "Discharge amount per unit time ( It is preferable to control the gear pump so that the speed is 3 mm3/sec).

The nozzle 41 is moved by the moving device 43 in the tire axial direction AD and the tire radial direction RD. Furthermore, the angle of the nozzle 41 with respect to the tire radial direction RD can be changed by a moving device 43. Thereby, the nozzle 41 can move in the tire axial direction AD while arranging the discharge port 45 to face the curved inner surface 1A of the tire in the tread 2 and maintaining a constant distance D1.

The moving device 43 is provided with a nozzle rotation device 46 that rotates the nozzle 41 . The nozzle rotation device 46 is provided at the tip of the arm 43A, and the nozzle 41 is attached to the arm 43A via the nozzle rotation device 46. By rotating the nozzle 41, the discharge port 45 at the tip thereof is configured to rotate.

When manufacturing the tire 1 using the tire manufacturing device 20, the vulcanized tire 1 is placed on the support device 30, and the nozzle 41 of the discharge device 40 is moved into the tire 1 to open the discharge port 45 into the inner surface of the tire. Place it opposite to 1A. At that time, in this example, since the sealant layer 10 is provided on the inner surface of the tread 2 from one end to the other end in the tire axial direction AD, the nozzle 41 is installed at the tire inner surface 1A at the one end. Place it opposite.

Next, the tire 1 is rotated by the drive device 32 and the nozzle 41 is relatively moved along the tire circumferential direction CD, while the supply device 42 supplies the sealant material 11 to the nozzle 41, and the sealant material 11 is supplied to the nozzle 41 through the discharge port 45 of the nozzle 41. The sealant material 11 is discharged from the tire, and the belt-shaped sealant material 11 is applied to the tire inner surface 1A along the tire circumferential direction CD. More specifically, as shown in FIG. 3, a band-shaped sealant material 11 is formed on the tire inner surface 1A through a gap between the tire inner surface 1A and the bottom surface of the nozzle 41 facing thereto.

While applying the sealant material 11 along the tire circumferential direction CD in this manner, the moving device 43 gradually moves the nozzle 41 in the tire axial direction AD. As a result, the sealant material 11 discharged from the discharge port 45 is continuously applied along the tire circumferential direction CD while being displaced from one side in the tire axial direction AD to the other side, and is applied to adjacent parts in the tire axial direction AD. The sealant layer 10 is formed by pasting the sealant materials 11 with no gaps between them.

At that time, by moving the nozzle 41 at a constant speed in the tire axial direction AD, the band-shaped sealant material 11 is applied so as to be arranged in a spiral with a slightly inclined attitude with respect to the tire circumferential direction CD (spiral application). ) may be done.

In a preferred embodiment, as shown in FIG. 4, a band-shaped sealant material 11 is applied in parallel to the tire circumferential direction CD, and each time the sealant material 11 is applied once, the sealant material 11 is applied in a predetermined area G in the tire circumferential direction CD. By applying the coating at an angle with respect to the tire circumferential direction CD so as to give a feed of a pitch corresponding to the width dimension (substantially the same as the dimension W2 in the longitudinal direction DD of the discharge port 45), the parallel application part 12 and the inclined application part 13 may be applied. This coating configuration is called step coating.

In the example shown in FIG. 4, one end 2A of the tire inner surface 1A of the tread 2 in the tire axial direction AD is defined as the left side, and the other end 2B is defined as the right side. A band-shaped sealant material 11 is applied in steps over the end portion 2B. A coating start end 14 of the sealant 11 is formed by setting one point in the tire circumferential direction CD at the end 2A on the one side as a coating start position, and from there, the sealant material 11 is applied in parallel to the tire circumferential direction CD. After forming the parallel coating portion 12A and coating it once, the nozzle 41 is moved one pitch to the other side in the tire axial direction AD to form the first inclined coating portion 13A. Next, after forming the second parallel coating portion 12B, a second inclined coating portion 13B is formed, and this process is repeated until reaching the other end 2B. Then, the last parallel application part 12Y is formed at the other end 2B, and the application end part 15 of the sealant 11 is formed and terminated at a position that matches the immediately preceding inclined application part 13X.

In addition, in FIG. 4, the number of turns of the belt-shaped sealant material 11, that is, the number of turns of the parallel application part 12 is seven turns, but the number of turns of the sealant material 11 depends on the application width of the sealant material 11 and the formation width of the sealant layer 10. It can be set as appropriate. Although spiral coating and step coating have been described above, the present invention is not limited thereto, and various coating methods can be adopted.

[Second embodiment]
FIG. 6 is a side view and a bottom view of the nozzle 41 showing how the nozzle 41 of the second embodiment discharges the sealant material 11. As shown in FIG. 6, the discharge port 45 has a flat shape in which a length H2 of the nozzle 41 in the traveling direction TD is shorter than a length W2 of the nozzle 41 in the orthogonal direction DD orthogonal to the traveling direction TD. The discharge port 45 in this example is an opening having a rectangular shape.

The first side 51 is a side having a constriction that protrudes further inside the discharge port 45 than a first straight line 51s (virtual straight line) connecting the first corner 55 and the second corner 56. The constriction narrows the opening thickness of the discharge port 45. In the example of FIG. 6, the first side 51 is a single curved line, and the radius of curvature thereof is 8.2 mm, but is not limited thereto. The second side 52 is a side having a constriction that projects further inside the discharge port 45 than a second straight line 52s (virtual straight line) connecting the third corner 57 and the fourth corner 58. The constriction narrows the opening thickness of the discharge port 45. In the example of FIG. 6, the second side 52 is a single curved line, and the radius of curvature thereof is 8.2 mm, but is not limited thereto. The third side 53 is a third straight line 53s that connects the first corner 55 and the third corner 57. The fourth side 54 is a fourth straight line 54s that connects the second corner 56 and the fourth corner 58.
In this way, the discharge port 45 has a shape based on a quadrilateral including a trapezoid, and each side (first side 51, second side 52, third side 53, and fourth side 54) of the discharge port 45 It does not have a shape that bulges outward. Therefore, swell (expansion) of the sealant material 11 can be suppressed.

As shown in the figure, in the orthogonal direction DD, the length of the first side 51 and the length W2 of the second side 52 are the same, and both are W2 = 9.0 mm.

[Results of Comparative Example 1]
Although not shown in the drawings, the nozzle of Comparative Example 1 has an ejection opening in the shape of a new circle with a diameter of 4.0 mm when viewed from the bottom. FIG. 7A is a schematic diagram showing the shape of the sealant layer 10 applied by the nozzle of Comparative Example 1. Since the shape of the discharge port of the nozzle 41 of Comparative Example 1 is a circular shape that expands outward from the discharge port, swell (expansion) of the discharged sealant material occurs. Therefore, a circular uneven shape is formed on the surface of the sealant layer 10 formed on the tire inner surface 1A.

[Results of second embodiment]
FIG. 7(b) is a schematic diagram showing the shape of the sealant layer 10 applied by the nozzle 41 of the second embodiment shown in FIG. As shown in FIG. 6, since constrictions are formed on the first side 51 and second side 52 of the discharge port 45, swell (expansion) is suppressed compared to a rectangular discharge port without constrictions. The cross-sectional shape of the sealant material is nearly square. However, as shown in the side view of FIG. 6, since the sealant material 11 discharged from the discharge port 45 bends toward the rear side TD2 in the traveling direction TD, the amount of sealant material passing through the corner inside R1 is larger than the amount of sealant material passing through the corner outside R2. More sealant material passes through. The discharged sealant material 11 is held down by the bottom surface of the nozzle 41, and the excess sealant material 11 has no choice but to escape to the side. As a result, as shown in FIG. 8(a), excess sealant material on the tire inner surface 1A side escapes laterally. Although the originally preferable cross-sectional shape is a square, the side surface of the sealant material 11 is shaped to protrude. Next, as shown in FIG. 8(b), if the sealant material 11 is discharged from the nozzle 41 at a position adjacent to the sealant material 11 formed on the tire inner surface 1A, the excess sealant material on the tire inner surface 1A side is removed. It is conceivable that the sealant material 11 escapes in the opposite direction, and the escaped sealant material 11 pushes up the adjacent sealant material 11, and as a result, unevenness is likely to occur in the sealant layer 10.

[Results of the first embodiment]
FIG. 7(c) is a schematic diagram showing the shape of the sealant layer 10 applied by the nozzle 41 of the first embodiment shown in FIG. As shown in FIG. 5, since constrictions are formed on the first side 51 and second side 52 of the discharge port 45, swell (expansion) is suppressed compared to a rectangular discharge port without constrictions. The cross-sectional shape of the sealant material is nearly square. As shown in the side view of FIG. 5, since the sealant material 11 discharged from the discharge port 45 bends toward the rear side TD2 in the traveling direction TD, the amount of sealant material passing through the corner outside R2 is larger than that passing through the corner inside R1. The amount of material increases. Therefore, as shown in the bottom view of FIG. 5, the length W1 of the first side 51 located on the front side TD1 of the discharge port 45 in the traveling direction TD is the same as the length W1 of the first side 51 located on the rear side TD2 of the discharge port 45 in the traveling direction TD. It is shorter than the length W2 of the two sides 52. As a result, it is possible to suppress the amount of sealant material 11 discharged from the vicinity of the first side 51 from becoming larger than the amount of sealant material 11 discharged from the vicinity of the second side 52, and the amount of sealant material 11 discharged from the vicinity of the first side 51 can be suppressed from becoming larger than the amount of sealant material 11 discharged from the vicinity of the second side 52, so that the It is possible to suppress the formation of sealant material. As shown in FIG. 8(c), the cross-sectional shape of the sealant material 11 can be made closer to the original preferred rectangular shape, and the unevenness of the sealant layer 10 can be reduced.

[Modified example]
(A) In the first embodiment, a constriction is formed on both the first side 51 and the second side 52, but as shown in FIG. A constriction may be formed on one side. In the example of FIG. 9A, the first side 51 has a constriction, and the second side 52 is a second straight line 52s without a constriction, but the present invention is not limited to this. For example, the first side 51 may be a first straight line 51s without a constriction, and the second side 52 may have a constriction.
Similarly to the second embodiment, a constriction may be formed on either the first side 51 or the second side 52.

(B) As shown in FIG. 9B, at least one of the third side 53 and the fourth side 54 may have a constriction that projects inside the discharge port 45. In the example of FIG. 9(b), both the third side 53 and the fourth side 54 have constrictions, but the present invention is not limited to this.

(C) Although the constriction in the above embodiment is one curved line (circular arc), it is not limited to this. The constricted side may be composed of a plurality of curved lines, a plurality of straight lines, or a combination of one or more straight lines and one or more curved lines.

[1]
As described above, the method for manufacturing a pneumatic tire involves rotating the nozzle 41 facing the inner surface 1A of the tire relatively around the axis of the tire, and discharging the belt-shaped sealant material from the outlet 45 of the nozzle 41. 11 to the inner surface 1A of the tire to form a sealant layer 10 on the inner surface 1A of the tire, the discharge port 45 is connected to the first side 51 located on the front side TD1 in the traveling direction TD of the nozzle 41, and the nozzle and a second side 52 located on the rear side TD2 in the traveling direction TD of the discharge port 41, and at least one of the first side 51 and the second side 52 has a constriction that projects inside the discharge port 45. good.

The sealant material 11 discharged from the vicinity of the first side 51 of the nozzle 41 becomes a part of the sealant layer 10 formed on the tire inner surface 1A on the tire inner surface 1A side, and is discharged from the vicinity of the second side 52 of the nozzle 41. The sealant material 11 becomes a part of the sealant layer 10 formed on the tire inner surface 1A on the side opposite to the tire inner surface 1A side. The first side 51 and the second side 52 of the nozzle 41 correspond to both sides in the thickness direction of the sealant layer 10 formed on the inner surface 1A of the tire, respectively. Since at least one of the first side 51 and the second side 52 of the nozzle 41 has a constriction, the amount of excess sealant 11 can be reduced, and the unevenness of the sealant layer can be reduced.
The sealant layer needs to have a predetermined required thickness in order to close the hole opened in the tire, and the thinnest concave portion of the unevenness that occurs in the sealant layer is set to the predetermined required thickness. If the unevenness of the sealant layer can be reduced, it is possible to reduce the sealant layer in the convex portions that do not contribute to the puncture prevention function, and it is possible to suppress an increase in the weight of the tire, which in turn makes it possible to suppress the deterioration of fuel efficiency due to the increase in the weight of the tire.

[2]
In the method for manufacturing a pneumatic tire according to [1] above, the discharge port 45 includes the first corner 55, the second corner 56, the third corner 57, the fourth corner 58, the third side 53, and the second corner 56. It has four sides 54, and the first side 51 is a side that protrudes inside the discharge port 45 from the first straight line 51s or the first straight line 51s connecting the first corner 55 and the second corner 56. , the second side 52 is a side that protrudes inside the discharge port 45 from the second straight line 52s or the second straight line 52s connecting the third corner 57 and the fourth corner 58, and the third side 53 is , a third straight line 53s connecting the first corner 55 and the third corner 57 or a side that projects inward of the discharge port 45 from the third straight line 53s; It may be a fourth straight line 54s that connects the fourth corner 58 and the fourth straight line 54s, or a side that protrudes inward of the discharge port 45 from the fourth straight line 54s.
In this way, the discharge port 45 has a shape based on a square including a rectangle or a trapezoid, and each side does not have a shape that spreads outward of the discharge port 45, so that the swell of the sealant material 11 can be suppressed, and the remaining It is possible to reduce the formation of unevenness in the sealant material.

[3]
In the method for manufacturing a pneumatic tire described in [2] above, at least one of the third side 53 and the fourth side 54 may have a constriction that projects inside the discharge port 45.
Since it is possible to suppress the sealant material 11 discharged from the discharge port 45 from swelling (expanding) laterally, it is possible to reduce the unevenness of the sealant layer 10 formed on the tire inner surface 1A.

[4]
In the method for manufacturing a pneumatic tire according to any one of [1] to [3] above, the discharge port 45 has a length in the orthogonal direction DD where the length W2 of the nozzle 41 in the traveling direction TD is perpendicular to the traveling direction TD. It may be a flat shape shorter than H1.
According to this configuration, it is easy to form the thin and wide sealant layer 10 on the inner surface 1A of the tire, which is suitable.

[5]
In the method for manufacturing a pneumatic tire according to any one of [1] to [4] above, the length W1 of the first side 51 in the orthogonal direction DD perpendicular to the traveling direction TD is equal to the length W1 of the second side 52 in the orthogonal direction DD. It may be shorter than the length W2.
The sealant material 11 discharged from the nozzle 41 is formed on the tire inner surface 1A while bending as the nozzle 41 advances. The route R2 of the sealant material 11 discharged from the vicinity of the first side 51 is more circumferential than the route R1 of the sealant material 11 discharged from the vicinity of the second side 52. The amount of the sealant material 11 discharged from the vicinity of the second side 52 is greater than the amount of the sealant material 11 discharged from the vicinity of the second side 52. As a result, the excess sealant 11 reaching the inner surface of the tire 1A and exceeding the required amount escapes in the width direction (orthogonal direction DD of the nozzle 41) perpendicular to the thickness direction of the sealant layer 10, pushing up the already formed sealant material 11, Irregularities are formed on the sealant layer 10.
With the above configuration, the amount of sealant material 11 discharged from the vicinity of the first side 51 is suppressed from becoming larger than the amount of sealant material 11 discharged from the vicinity of the second side 52. This makes it possible to reduce the amount of unevenness on the sealant layer 10, thereby suppressing the formation of unevenness on the sealant layer 10.

[6]
The pneumatic tire manufacturing apparatus includes a support device 30 that supports the tire 1, and a nozzle 41 that can discharge a band-shaped sealant material 11 from a discharge port 45. The belt-shaped sealant material 11 discharged from the discharge port 45 of the nozzle 41 can be applied to the inner surface 1A of the tire while rotating relatively around the axis of the tire. It has a first side 51 located on the front side TD1 in the traveling direction TD of the nozzle 41 and a second side 52 located on the rear side TD2 in the traveling direction TD of the nozzle 41, and the first side 51 and the second side 52 At least one of them may have a constriction that projects inside the discharge port 45.

Although the embodiments of the present disclosure have been described above based on the drawings, it should be understood that the specific configuration is not limited to these embodiments. The scope of the present disclosure is indicated not only by the description of the embodiments described above but also by the claims, and further includes all changes within the meaning and scope equivalent to the claims.

It is possible to apply the structure adopted in each of the above embodiments to any other embodiment. The specific configuration of each part is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present disclosure.

For example, the execution order of each process such as operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, specification, and drawings is such that the output of the previous process is They can be implemented in any order unless used in processing. Even if "first", "next", etc. are used to explain the claims, specification, and flows in the drawings for convenience, this does not mean that they must be executed in this order. .

DESCRIPTION OF SYMBOLS 1... Tire, 1A... Inner surface, 10... Sealant layer, 11... Sealant material, 30... Support device, 41... Nozzle, 45... Discharge port, 51... First side, 51s... First straight line, 52... Second side, 52s...second straight line, 53...third side, 53s...third straight line, 54...fourth side, 54s...fourth straight line, 55...first corner, 56...second corner, 57...third corner , 58... Fourth corner, TD... Traveling direction (lateral direction), TD1... Front side in the traveling direction, TD2... Rear side in the traveling direction, DD... Orthogonal direction (longitudinal direction).

Claims (6)

Applying sealant to the inner surface of the tire by applying a band-shaped sealant material discharged from the discharge port of the nozzle to the inner surface of the tire while rotating a nozzle facing the inner surface of the tire relatively around the axis of the tire. forming a layer;
including;
The discharge port has a first side located on the front side in the traveling direction of the nozzle, and a second side located on the rear side in the traveling direction of the nozzle,
A method for manufacturing a pneumatic tire, wherein at least one of the first side and the second side has a constriction that projects inside the discharge port. The discharge port has a first corner, a second corner, a third corner, a fourth corner, a third side, and a fourth side,
The first side is a first straight line connecting the first corner and the second corner, or a side that protrudes further inside the discharge port than the first straight line,
The second side is a second straight line connecting the third corner and the fourth corner, or a side that projects further inside the discharge port than the second straight line,
The third side is a third straight line connecting the first corner and the third corner, or a side that protrudes further inside the discharge port than the third straight line,
The air according to claim 1, wherein the fourth side is a fourth straight line connecting the second corner and the fourth corner or a side that projects further inside the discharge port than the fourth straight line. A method of manufacturing tires. 3. The method for manufacturing a pneumatic tire according to claim 2, wherein at least one of the third side and the fourth side has a constriction that projects inside the discharge port. The method for manufacturing a pneumatic tire according to claim 1, wherein the discharge port has a flat shape in which the length of the nozzle in the traveling direction is shorter than the length in the orthogonal direction perpendicular to the traveling direction. The method for manufacturing a pneumatic tire according to claim 1, wherein the length of the first side in the orthogonal direction perpendicular to the traveling direction is shorter than the length of the second side in the orthogonal direction. a support device that supports the tire;
Equipped with a nozzle capable of discharging a band-shaped sealant material from the discharge port,
A belt-shaped sealant material discharged from a discharge port of the nozzle can be applied to the inner surface of the tire while a nozzle directed toward the inner surface of the tire is rotated relatively around an axis of the tire. and
The discharge port has a first side located on the front side in the traveling direction of the nozzle, and a second side located on the rear side in the traveling direction of the nozzle,
A pneumatic tire manufacturing apparatus, wherein at least one of the first side and the second side has a constriction that projects inside the discharge port.