Method for manufacturing pneumatic tires

Abstract

To optimize a rubber amount of a belt-like rubber member according to a cross-sectional shape of molded decoration.SOLUTION: A manufacturing method of a pneumatic tire 10 includes: molding a belt-like rubber member 58 according to a cross-sectional shape of decoration 31A; molding a green tire 50 by winding the belt-like rubber member 58 together with tread rubber 55 and side wall rubber 59; and vulcanization-molding the green tire 50 by a tire vulcanization die 80. The belt-like rubber member 58 is trapezoid-shaped in cross-section, a thickness t from a lower side 58a to an upper side 58b is set according to a size S in a tire axial direction TA and the cross-sectional shape of the decoration 31A, and a length L1 of the upper side 58b is set according to a width W in a tire radial direction TR and the cross-sectional shape of the decoration 31A.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a method for manufacturing a pneumatic tire with decorations such as protrusions in the buttress region on the radially outer side of the sidewall. In this manufacturing method, a strip-shaped rubber member is additionally attached to the decoration molding region of a green tire to prevent a shortage of rubber in the decoration molding region. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-39961 Summary of the Invention [Problem to be solved by the invention]

[0004] The amount of rubber required to mold the decoration varies depending on the shape of the decoration, and the manufacturing method of Patent Document 1 does not take into consideration the amount of rubber required depending on the shape of the decoration.

[0005] An object of the present invention is to provide a method for manufacturing a pneumatic tire that can optimize the amount of rubber in a belt-shaped rubber member depending on the cross-sectional shape of the decoration to be molded. [Means for solving the problem]

[0006] The present invention In the manufacturing method of pneumatic tiresa belt-shaped rubber member having a trapezoidal cross section, the thickness from the lower side to the upper side being set in accordance with the dimension in the tire axial direction and the cross-sectional shape of a decoration, which is a protrusion or depression provided in a buttress region on the outer side of the sidewall in the tire radial direction, and the length of the upper side being set in accordance with the width in the tire radial direction and the cross-sectional shape of the decoration; a green tire is molded by arranging the belt-shaped rubber member so as to be positioned in an area where the decoration is molded with respect to sidewall rubber constituting the sidewall; and vulcanizing and molding the green tire using a tire vulcanizing mold having a molding portion corresponding to the cross-sectional shape of the decoration. do.

[0007] The thickness of the band-shaped rubber member is set according to the axial dimension and cross-sectional shape of the decoration, and the length of the upper edge of the band-shaped rubber member is set according to the radial width and cross-sectional shape of the decoration. In other words, band-shaped rubber members of different thicknesses and lengths are prepared according to the cross-sectional shape of the decoration, so the amount of rubber in the band-shaped rubber member can be optimized. Therefore, when the green tire is vulcanized, rubber can be distributed to the corners of the uneven shape of the decoration, allowing the desired shape of the decoration to be molded. Furthermore, because the band-shaped rubber member is positioned relative to the sidewall rubber so as to be located in the area where the decoration is molded, no additional rubber parts are required for the molded green tire. This improves workability when molding the green tire.

[0008] One aspect of the present invention is When the cross-sectional shape of the decoration is arched or trapezoidal, the thickness and length of the belt-shaped rubber member satisfy the following: To provide a method for manufacturing a pneumatic tire .

[0009] [Number 1] 1.5S≦t≦2.0S 0.75W≦L1≦1.25W S: Dimension of decoration in tire axial direction W: Width of decoration in the radial direction of the tire t: Thickness of the rubber strip L1: Length of the top edge of the belt-shaped rubber member

[0010] Another aspect of the present invention isWhen the cross-sectional shape of the decoration is triangular, the thickness and the length of the belt-shaped rubber member satisfy the following: To provide a method for manufacturing a pneumatic tire .

[0011] [Number 2] 1.0S≦t≦1.5S 0.75W≦L1≦1.25W S: Dimension of decoration in tire axial direction W: Width of decoration in the radial direction of the tire t: Thickness of the rubber strip L1: Length of the top edge of the belt-shaped rubber member

[0012] If the thickness and length of the band-shaped rubber member are excessively large, excessive unevenness (steps) will occur between the rubber members of the molded green tire, which may result in air pockets in the molded pneumatic tire. On the other hand, if the thickness and length of the band-shaped rubber member are excessively small, there is a risk of insufficient thickness occurring around the decoration of the molded pneumatic tire. In contrast, the thickness and length of the band-shaped rubber member are set within the above-mentioned ranges according to the shape of the decoration, thereby preventing problems such as air pockets and insufficient thickness.

[0013] Yet another aspect of the present invention is the belt-shaped rubber member of The length of the bottom side teeth longer than the length of the upper side, When molding the green tire, With the lower side attached to both sides of the tread rubber that makes up the tread The belt-shaped rubber member Can be wrapped around To provide a method for manufacturing a pneumatic tire .

[0014] The band-shaped rubber member is wound around the tread rubber with its lower side attached to both sides of the tread rubber, which improves the winding workability when forming the green tire.

[0015] Yet another aspect of the present invention is After the belt-shaped rubber member is wound, the sidewall rubber is wound around the belt-shaped rubber member so that a portion of the sidewall rubber overlaps the outer side of the belt-shaped rubber member in the tire axial direction. To provide a method for manufacturing a pneumatic tire .

[0016] The aforementionedThe belt-shaped rubber member is wound around the outer side in the tire axial direction of the outer portion of the sidewall rubber in the tire radial direction. Good .

[0017] The band-shaped rubber member is wrapped around the axially inner or outer side of the sidewall rubber. This allows the band-shaped rubber member to be reliably positioned in the decorative molding area corresponding to the buttress area. This ensures a sufficient amount of rubber in the decorative molding area, ensuring that the desired shape of the decoration can be molded reliably.

[0018] Yet another aspect of the present invention provides a method for manufacturing a pneumatic tire, wherein the length of a first side edge of the band-shaped rubber member is longer than the length of a second side edge, and when molding the green tire, the band-shaped rubber member is wound so that the first side edge is positioned radially outward of the second side edge.

[0019] When the radial range of the buttress region from the maximum width position of the sidewall that protrudes furthest outward in the tire axial direction to the outer edge of the tread surface that is located furthest outward in the tire axial direction is taken as 1, the decoration is molded in a range of 0.3 to 0.8 with the maximum width position as the reference. The aesthetic appearance of the side surface of the pneumatic tire can be improved. [Effects of the Invention]

[0020] In the present invention, the amount of rubber in the belt-shaped rubber member can be optimized according to the cross-sectional shape of the decoration to be molded. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of a pneumatic tire manufactured by a manufacturing method according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged perspective view of a portion II in FIG. [Figure 3] FIG. 1 is a cross-sectional view showing a green tire before vulcanization and a tire vulcanization mold. [Figure 4] FIG. 4 is a cross-sectional view showing the tread rubber of FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view showing the belt-shaped rubber member of FIG. 3. [Figure 6] 6 is a cross-sectional view of the tread rubber of FIG. 4 to which the band-shaped rubber member of FIG. 5 is attached. [Figure 7] FIG. 2 is a cross-sectional view showing a green tire in a vulcanized state. [Figure 8] FIG. 10 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to a second embodiment. [Figure 9] FIG. 10 is a perspective view similar to FIG. 2 showing a pneumatic tire according to a third embodiment. [Figure 10]FIG. 10 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to a third embodiment. [Figure 11] FIG. 10 is a perspective view similar to FIG. 2 showing a pneumatic tire according to a fourth embodiment. [Figure 12] FIG. 10 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to a fourth embodiment. [Figure 13] FIG. 10 is a perspective view similar to FIG. 2 showing a pneumatic tire according to a fifth embodiment. [Figure 14] FIG. 10 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to a fifth embodiment. [Figure 15] FIG. 10 is a perspective view similar to FIG. 2 showing a pneumatic tire according to a sixth embodiment. [Figure 16] FIG. 13 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to a sixth embodiment. [Figure 17] FIG. 10 is a perspective view similar to FIG. 2 showing a pneumatic tire according to a seventh embodiment. [Figure 18] FIG. 13 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to a seventh embodiment. [Figure 19] FIG. 11 is a perspective view similar to FIG. 2 showing a pneumatic tire according to an eighth embodiment. [Figure 20] FIG. 13 is a cross-sectional view showing a green tire and a tire vulcanizing mold according to an eighth embodiment. [Figure 21] FIG. 10 is a perspective view showing a modified example of a pneumatic tire to be manufactured. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] (First embodiment) FIG. 1 shows a pneumatic tire 10 manufactured by a manufacturing method according to a first embodiment of the present invention. The pneumatic tire 10 has a decoration 31A in a buttress region 30. Referring to FIG. 3, a green tire 50 before vulcanization has a band-shaped rubber member 58 arranged in a region (decoration molding region) 50a where the decoration 31A is molded. In the present invention, different band-shaped rubber members 58 are prepared according to the cross-sectional shape of the decoration 31A, and the amount of rubber in the decoration molding region 50a corresponding to the buttress region 30 is optimized.

[0024] First, the configuration of a pneumatic tire 10 will be described with reference to FIGS.

[0025] 1 and 2, the tire axial direction is indicated by the symbol TA, the tire radial direction is indicated by the symbol TR, the tire circumferential direction is indicated by the symbol TC, and the tire equator line is indicated by the symbol CL. The meridian cross-sectional view in Fig. 1 shows only the right side of the pneumatic tire 10, and the left side of the pneumatic tire 10 appears symmetrical to Fig. 1 with respect to the tire equator line CL.

[0026] 1, a pneumatic tire 10 is for a light truck, which has a larger diameter than pneumatic tires for passenger cars, although the present invention is not limited to such applications.

[0027] The pneumatic tire 10 includes a tread 11, a pair of sidewalls 12, and a pair of bead portions (not shown). A carcass 14 is provided between the pair of bead portions. An inner liner 15 is provided inside the carcass 14.

[0028] The tread 11 has a cylindrical shape extending in the tire axial direction TA. In the tread 11, a belt layer 16 consisting of three laminated belts 17A, 17B, 17C is provided on the outer side of the carcass 14 in the tire radial direction TR. A pad 18 is provided on the inner side of the belt layer 16 in the tire radial direction TR on the outer side of the tread 11 in the tire axial direction TA (direction away from the tire equator line CL). A tread rubber layer 19 is provided on the outer side of the belt layer 16 in the tire radial direction TR.

[0029] The pad 18 is provided between the belt 17A located at the innermost position in the tire radial direction TR and the carcass 14. More specifically, on the outer side of the tread 11 in the tire axial direction TA, the belt layer 16 extends in the tire axial direction TA. As the carcass 14 moves toward the outer side in the tire axial direction TA, it curves inward in the tire radial direction TR and moves away from the belt 17A. The pad 18 complements the gap between the belt 17A and the carcass 14, which are gradually spaced apart.

[0030] The tread rubber layer 19 includes a base 20 provided on the outer side of the belt layer 16 in the tire radial direction TR, and a cap 21 provided on the outer side of the base 20 in the tire radial direction TR. The base 20 protrudes outward from the outer end of the belt layer 16 in the tire axial direction TA, then extends inward in the tire radial direction TR, and is overlapped on the outer side of the pad 18 in the tire axial direction TA. The cap 21 is located on the outermost side of the pneumatic tire 10 in the tire radial direction TR. The cap 21 is provided with a plurality of main grooves 11a extending in the tire circumferential direction TC, and lateral grooves (not shown) extending in the tire axial direction TA. The outer side of the cap 21 in the tire radial direction TR is a tread surface 11b that comes into contact with the road surface, and the outermost portion of the tread surface 11b in the tire axial direction TA is an outer end 11c of the tread surface 11b.

[0031] Each sidewall 12 is connected to an end of the tread 11 in the tire axial direction TA and extends inward in the tire radial direction TR. In this specification, the sidewall 12 is defined as the portion of the inner liner 15 located outermost in the tire radial direction TR, i.e., the portion inward in the tire radial direction TR from the intersection of the inner surface of the inner liner 15 and the tire equator line CL. Therefore, a portion of each of the pad 18 and the base 20 constitutes a portion of the sidewall 12.

[0032] In the sidewall 12, a sidewall rubber layer 22 is provided on the outer side of the carcass 14 in the tire axial direction TA. The sidewall rubber layer 22 extends from the cap 21 to the bead portion at the outermost side in the tire axial direction TA. More specifically, the sidewall rubber layer 22 covers the outer side of each of the cap 21, base 20, pad 18, and carcass 14 in this order from the outer side in the tire radial direction TR.

[0033] Of the sidewall rubber layer 22, the outer portion 22a shown by cross-hatching in Fig. 1 is made up of a sidewall rubber 59 and a band-shaped rubber member 58 (see Fig. 3), which will be described later. The outer portion 22a is configured such that the sidewall rubber 59 and the band-shaped rubber member 58, both made of rubber with the same components, are integrated by vulcanization. Of the sidewall rubber layer 22, the inner portion 22b shown by hatching slanting upward to the right in Fig. 1, is made up of only the sidewall rubber 59.

[0034] In the pneumatic tire 10 having the above basic structure, a buttress region 30 is set on the outer side of the sidewall 12 in the tire radial direction TR, and a decoration 31A is provided in this buttress region 30.

[0035] The buttress region 30 is the radial range from the maximum width position 12a of the sidewall 12 that protrudes furthest outward in the tire axial direction TA to the outer end 11c of the tread 11. In other words, the buttress region 30 is made up of the outer surface of the tread 11 in the tire axial direction TA and part of the outer surface of the sidewall 12. During normal driving on flat paved roads, the buttress region 30 does not come into contact with the ground.

[0036] When the radial range (H) of the buttress region 30 is defined as 1, the ornament 31A is molded within a range (h) of 0.3 to 0.8 (0.3H≦h≦0.8H) based on the maximum width position 12a of the sidewall 12, i.e., the inner end of the buttress region 30 in the tire radial direction TR. If the ornament 31A is molded beyond the upper limit of this range, it will be too close to the tread 11b, and if the ornament 31A is molded below the lower limit of this range, it will be too close to the bead portion. Therefore, in either case, the decorativeness of the ornament 31A will be reduced. Therefore, it is preferable to mold the ornament 31A within the above-mentioned range. In this embodiment, the ornament 31A is molded within the above-mentioned range (h) outside the center (0.5H) of the radial range (H) of the buttress region 30 in the tire radial direction TR.

[0037] 2, the decoration 31A is a protrusion that protrudes outward in the tire axial direction TA from the curved surface 30a of the buttress region 30. The decoration 31A has a bow-shaped cross section and is provided continuously in the tire circumferential direction TC so as to form an annular shape when viewed from the outside in the tire axial direction TA. The decoration 31A is connected to the surface 30a via an annular inner edge 31a and an annular outer edge 31b.

[0038] The thickness (dimension) S of the decoration 31A in the tire axial direction TA, more specifically, the radial thickness S of the decoration 31A from the surface 30a of the buttress region 30 to the widest position of the decoration 31A, is set in the range of 0.3 mm to 4.0 mm. The width W of the decoration 31A in the tire radial direction TR, more specifically, the width W of the decoration 31A from the inner edge 31a to the outer edge 31b, is set in the range of 1 mm to 50 mm. If the thickness S and width W of the decoration 31A are excessively large or if the thickness S and width W of the decoration 31A are excessively small, the decorativeness of the decoration 31A will be impaired. Therefore, it is preferable to set the thickness S and width W of the decoration 31A within the above-specified range.

[0039] Next, a method for manufacturing the pneumatic tire 10 having the above configuration will be described.

[0040] First, tire constituent members constituting the tread 11, sidewalls 12, and bead portions shown in Fig. 1 are prepared. Next, the tire constituent members are wound around a building drum (not shown) in a predetermined order to form a green tire 50 (see Fig. 3). Finally, the green tire 50 is vulcanized using a vulcanization molding machine equipped with a tire vulcanization mold 80 (see Fig. 7).

[0041] Referring to Figure 3, the tire components that make up the tread 11 and sidewall 12 include a carcass ply 51, inner liner rubber 52, belt plies 53A to 53C, pad rubber 54, tread rubber 55, and sidewall rubber 59, which correspond to the carcass 14, inner liner 15, belts 17A to 17C, pad 18, tread rubber layer 19, and sidewall rubber layer 22 shown in Figure 1.

[0042] Of these tire constituent members, the tread rubber 55 includes a base rubber 56 and a cap rubber 57. A band-shaped rubber member 58 molded separately from the tread rubber 55 is attached integrally to the tread rubber 55.

[0043] Referring to Figure 4, the base rubber 56 has a cross-sectional shape defined by a lower edge 56a, an upper edge 56b, and a pair of side edges 56c, and extends in a direction perpendicular to the plane of the paper in Figure 4. The lower edge 56a extends linearly. The upper edge 56b is inclined upward from the center in the width direction, which is the left-right direction in Figure 4, to both sides. The pair of side edges 56c are inclined toward the center in the width direction from the end of the lower edge 56a to the end of the upper edge 56b.

[0044] Continuing to refer to FIG. 4, the cap rubber 57 has a cross-sectional shape defined by a lower edge 57a, an upper edge 57b, and a pair of side edges 57c, and extends in a direction perpendicular to the plane of the paper in FIG. 4. The lower edge 57a has a shape corresponding to the upper edge 56b of the base rubber 56. The upper edge 57b has a shape that protrudes on both sides in the width direction, which is the left-right direction in FIG. 4. Both sides of the cap rubber 57 are portions that mold the outer end 11c of the tread 11 shown in FIG. 2, and have a protruding shape that can ensure an amount of rubber to sufficiently spread the rubber to the corresponding corner 82c (see FIG. 7) of the tire vulcanization mold 80. The pair of side edges 57c are inclined toward the center in the width direction from the end of the lower edge 57a toward the end of the upper edge 57b. The inclination angle of the side 57c is approximately the same as the inclination angle of the side 56c of the base rubber 56, and the side 57c of the cap rubber 57 extends approximately linearly relative to the side 56c of the base rubber 56.

[0045] The base rubber 56 and the cap rubber 57 are made of rubbers with different components, and are extruded by an extruder (not shown) equipped with a nozzle having a first nozzle for the base rubber 56 and a second nozzle for the cap rubber 57, and then bonded together.

[0046] 3, the band-shaped rubber member 58 is provided to ensure the amount of rubber in the ornament molding region 50a where the ornament 31A (see FIG. 2) is molded. The ornament molding region 50a corresponds to the buttress region 30 shown in FIG. 1. The band-shaped rubber member 58 of this embodiment is disposed between the tread rubber 55 and the sidewall rubber 59, with a portion of it exposed to the surface.

[0047] The belt-shaped rubber member 58 is molded by an extruder (not shown) separately from the base rubber 56 and the cap rubber 57. The belt-shaped rubber member 58 is made of a rubber having a different composition from the base rubber 56 and the cap rubber 57, and in this embodiment, the belt-shaped rubber member 58 is molded from a rubber having the same composition as the sidewall rubber 59.

[0048] Referring to FIG. 5, the band-shaped rubber member 58 has a trapezoidal cross section and is defined by a bottom edge 58a, a top edge 58b, a first side edge 58c, and a second side edge 58d, extending in a direction perpendicular to the plane of the paper in FIG. 5. The bottom edge 58a is longer than the top edge 58b. The top edge 58b extends along the bottom edge 58a. The first side edge 58c is longer than the second side edge 58d. The first side edge 58c is connected to one end of the bottom edge 58a and one end of the top edge 58b via a chamfer 58e. The second side edge 58d is connected to the other end of the bottom edge 58a and the other end of the top edge 58b via the chamfer 58e. However, the bottom edge 58a may be directly connected to the side edges 58c and 58d without providing the chamfer 58e.

[0049] 6, the belt-shaped rubber member 58 is attached with its bottom edge 58a overlapping the side edge 56c of the base rubber 56 and the side edge 57c of the cap rubber 57, i.e., the side edges of the tread rubber 55 (both sides of the sheet-like tread rubber 55). The outer end of the first side edge 58c is disposed at the end of the side edge 57c of the cap rubber 57 opposite the base rubber 56, and the belt-shaped rubber member 58 is disposed so as to protrude from the base rubber 56.

[0050] 5, the thickness t of the belt-shaped rubber member 58 from the lower side 58a to the upper side 58b is set based on the thickness (dimension) S of the ornament 31A shown in Fig. 2 and the cross-sectional shape of the ornament 31A. The length L1 of the upper side 58b is set based on the width W of the ornament 31A shown in Fig. 2 and the cross-sectional shape of the ornament 31A. The length L2 of the lower side 58a and the length L3 of the first side side 58c are set based on the length of the side side 56c of the base rubber 56 and the length of the side side 57c of the cap rubber 57 shown in Fig. 4, i.e., the length of the side side of the tread rubber 55.

[0051] Specifically, when the cross section of the decoration 31A is an arched projection as shown in FIG. 2, the thickness t and length L1 of the belt-shaped rubber member 58 shown in FIG. 5 are set to satisfy the following.

[0052] [Number 3] 1.5S≦t≦2.0S 0.75W≦L1≦1.25W S: Dimension of decoration in tire axial direction W: Width of decoration in the radial direction of the tire t: Thickness of the rubber strip L1: Length of the top edge of the belt-shaped rubber member

[0053] If the thickness t and length L1 of the band-shaped rubber member 58 are made excessively large, excessive unevenness (steps) will occur between the rubber members of the molded green tire 50 shown in Figure 3, which may result in air pockets in the molded pneumatic tire 10. On the other hand, if the thickness t and length L1 of the band-shaped rubber member 58 are made excessively small, there is a risk that an insufficient thickness will occur around the decoration 31A in the molded pneumatic tire 10. To prevent these inconveniences, when the cross-sectional shape of the decoration 31A is arched, it is preferable that the thickness t and length L1 of the band-shaped rubber member 58 be set within the above-specified ranges.

[0054] The length L2 of the bottom side 58a of the belt-shaped rubber member 58 shown in Fig. 5 is longer than the length of the side sides 56c, 57c of the tread rubber 55 shown in Fig. 4. When the length of the side sides 56c, 57c of the tread rubber 55 is L0, the length L2 of the bottom side 58a of the belt-shaped rubber member 58 and the length L3 of the first side side 58c are set to satisfy the following.

[0055] [Number 4] 1.1L0≦L2≦1.5L0 0.8L0≦L3≦1.2L0 L0: Length of the side of the tread rubber L2: Length of the bottom edge of the belt-shaped rubber member L3: Length of the first side of the belt-shaped rubber member

[0056] If the length L2 of the bottom edge 58a of the belt-shaped rubber member 58 and the length L3 of the first side edge 58c are made too short, or if these lengths L2, L3 are made too long, it becomes difficult to position the top edge 58b, which is the thickest part of the belt-shaped rubber member 58, in the decorative molding area 50a. To prevent such inconvenience, it is preferable that the length L2 of the bottom edge 58a of the belt-shaped rubber member 58 and the length L3 of the first side edge 58c of the belt-shaped rubber member 58 be set within the above-specified range.

[0057] Next, a method for forming the green tire 50 will be described.

[0058] First, the sidewall rubber 59, inner liner rubber 52, carcass ply 51, and components of the bead portion are wound around a forming drum, and then the pad rubber 54 is wound around the carcass ply 51. In this state, the forming drum is inflated (expanded) so that the sidewall rubber 59 extends in the radial direction of the forming drum.

[0059] Next, the belt plies 53A, 53B, and 53C are wound in this order on the carcass ply 51 so that portions of the belt plies 53A and 53B overlap the pad rubber 54. Next, the tread rubber 55 (base rubber 56 and cap rubber 57) to which the belt-shaped rubber member 58 is integrally attached is wound so as to cover the belt ply 53C and the pad rubber 54.

[0060] Next, by turning up the sidewall rubber 59, the sidewall rubber 59 is overlapped on the outside of the carcass ply 51, the pad rubber 54, and the belt-shaped rubber member 58, as shown in Fig. 3. As a result, the tip (free end) of the sidewall rubber 59, which was located on the innermost side in the tire radial direction TR, is now located on the outermost side in the tire radial direction TR. In other words, after winding the belt-shaped rubber member 58, the sidewall rubber 59 is wound so that a part of it overlaps the outer side of the belt-shaped rubber member 58 in the tire axial direction TA.

[0061] 1, the decoration 31A of this embodiment is provided outside the center (0.5H) in the tire radial direction TR within the radial range H of the buttress region 30. Therefore, as shown in Fig. 3, the belt-shaped rubber member 58 is disposed in a state where it protrudes outward from the outer end of the sidewall rubber 59 in the tire radial direction TR. This is to align the belt-shaped rubber member 58 with the molding position of the decoration 31A.

[0062] Next, a pressure roller (not shown) is pressed against the outer surfaces of the cap rubber 57, the sidewall rubber 59, etc. to remove air from between the rubbers, thereby completing the green tire 50. Thereafter, the green tire 50 is vulcanized in a tire vulcanizing mold 80, thereby completing the pneumatic tire 10.

[0063] Referring to Figures 3 and 7, the tire vulcanization mold 80 includes a sector mold 81 that molds the outer surface of the tread 11, a pair of side molds 83 that mold the outer surface of the sidewall 12 and the outer surface of the bead portion, and a bladder 85 that molds the inner surface of the pneumatic tire 10.

[0064] The sector mold 81 is cylindrical, and although in Figures 3 and 7 its axis is shown extending horizontally, in reality it is arranged so that its axis extends vertically. The sector mold 81 is divided into a plurality of sectors 82 in the circumferential direction. Each sector 82 is movable in the radial direction around the axis of the sector mold 81. The sector 82 is provided with a molding surface 82a that molds the tread surface 11b shown in Figure 1, and protrusions 82b that mold the main groove 11a and lateral grooves (not shown) shown in Figure 1.

[0065] The pair of side molds 83 are each annular and are arranged on both axial sides of the sector mold 81. One of the pair of side molds 83 (not shown) is immovably fixed, while the other (shown) is movable along the axis of the sector mold 81. Each side mold 83 is provided with a molding surface 83a that molds the surface of the sidewall 12 and the surface of the bead portion shown in FIG. 1, and a molding portion 84A that molds the decoration 31A.

[0066] The molded portion 84A has a shape corresponding to the cross-sectional shape of the ornament 31A shown in Fig. 2, and in this embodiment is configured as a recess (concave) with an arch-shaped cross section, extending into an annular groove. The molded surface 83a and the molded portion 84A are connected via a continuous portion 84a. The continuous portion 84a is an edge (convex) corresponding to the edges 31a, 31b of the ornament 31A shown in Fig. 2.

[0067] The bladder 85 is disposed within the sector mold 81 and can be expanded and contracted by an air supply device (not shown).

[0068] Next, vulcanization of the green tire 50 using the tire vulcanization mold 80 will be described.

[0069] First, the green tire 50 is placed in the opened tire vulcanizing mold 80, and the tire vulcanizing mold 80 is then clamped to begin vulcanization. When the mold is clamped, the cap rubber 57, the belt-shaped rubber member 58, and the sidewall rubber 59 are pressed by the sector mold 81 and the side mold 83. This pressure causes the cap rubber 57 to flow along the molding surface 82a, and the belt-shaped rubber member 58 and the sidewall rubber 59 to flow along the molding surface 83a.

[0070] In the area where molded portion 84A is formed, belt-shaped rubber member 58 and sidewall rubber 59 flow together as a single unit through vulcanization and enter molded portion 84A. Because the amount of rubber is secured by belt-shaped rubber member 58, excess rubber that exceeds the capacity of molded portion 84A flows from molded portion 84A to molding surface 83a. This ensures that the rubber is sufficiently distributed throughout continuous portion 84a.

[0071] When vulcanization is complete, the tire vulcanization mold 80 is opened and the pneumatic tire 10 is removed. This completes the pneumatic tire 10 as designed, as shown in FIGS.

[0072] The method for manufacturing the pneumatic tire 10 in this manner has the following features.

[0073] The thickness t of the band-shaped rubber member 58 is set according to the dimension (thickness) S of the ornament 31A in the tire axial direction TA and its cross-sectional shape, and the length L1 of the upper edge 58b of the band-shaped rubber member 58 is set according to the width W of the ornament 31A in the tire radial direction TR and its cross-sectional shape. In other words, because band-shaped rubber members 58 with different thicknesses t and lengths L1 are prepared according to the cross-sectional shape of the ornament 31A, the amount of rubber in the band-shaped rubber member 58 can be optimized. Therefore, when the green tire 50 is vulcanized, rubber can be distributed to the corners of the uneven shape of the ornament 31A, allowing the ornament 31A to be molded in the desired shape. Furthermore, because the band-shaped rubber member 58 is positioned relative to the sidewall rubber 59 so as to be located in the region 50a where the ornament 31A is molded, no additional rubber parts are required for the molded green tire 50. This improves workability when molding the green tire 50.

[0074] When the cross-sectional shape of the decoration 31A is arched, the thickness t of the belt-shaped rubber member 58 is set to be 1.5 to 2.0 times the dimension S of the decoration 31A in the tire axial direction TA, and the length L1 of the upper side 58b of the belt-shaped rubber member 58 is set to be 0.75 to 1.25 times the width W of the decoration 31A in the tire radial direction TR. This makes it possible to optimize the amount of rubber in the belt-shaped rubber member 58, thereby preventing air pockets from forming in the molded pneumatic tire 10 and preventing areas of insufficient thickness from occurring around the decoration 31A.

[0075] The length of the lower side 58a of the belt-shaped rubber member 58 is longer than the length of the upper side 58b, and the lower side 58a is attached to both sides of the tread rubber 55 in the width direction when the belt-shaped rubber member 58 is wound around the tread rubber 55. This improves the ease of winding work when the green tire 50 is molded.

[0076] After winding the strip-shaped rubber member 58, the sidewall rubber 59 is wound so that a portion of the sidewall rubber 59 overlaps the outer side of the strip-shaped rubber member 58 in the tire axial direction TA. This ensures that the strip-shaped rubber member 58 is positioned reliably in the ornament molding region 50a that corresponds to the buttress region 30. This ensures that the amount of rubber in the ornament molding region 50a is sufficient, ensuring that the ornament 31A of the desired shape can be molded reliably.

[0077] When the radial range H of the buttress region 30 is 1, the decoration 31A is molded in the range of 0.3 to 0.8 with respect to the maximum width position 12a. Therefore, the aesthetic appearance of the side surface of the pneumatic tire 10 can be improved.

[0078] Other embodiments and various modifications of the present invention will be described below, but in these descriptions, points that are not particularly mentioned are the same as those in the first embodiment. In the drawings referred to below, the same elements as those in the first embodiment are given the same reference numerals.

[0079] (Second embodiment) Fig. 8 shows a green tire 50 molded by the manufacturing method according to the second embodiment, and a tire vulcanizing mold 80. Referring to Fig. 8, the second embodiment differs from the first embodiment in that the position of the molding section 84A is changed, and the arrangement of the sidewall rubber 59 and the arrangement of the belt-shaped rubber member 58 in the tire radial direction TR are changed.

[0080] Specifically, in order to provide the decoration 31A within the above-specified range (0.3H≦h≦0.8H) of the radial range H of the buttress region 30 shown in FIG. 1 and further inward in the tire radial direction TR than the center (0.5H), the molding portion 84A is provided in the side mold 83 at a position farther from the sector mold 81 than the decoration 31A of the first embodiment.

[0081] In this case, the green tire 50 requires a larger amount of rubber on the inner side of the decoration molding region 50a in the tire radial direction TR than on the outer side. Therefore, the attachment position of the strip-shaped rubber member 58 relative to the tread rubber 55 is changed, or the dimension of the tread rubber 55 in the tire axial direction TA is changed, and the strip-shaped rubber member 58 is disposed on the inner side of the decoration molding region 50a in the tire radial direction TR. Also, the outer ends of the sidewall rubber 59 are disposed outward of the outer ends of the strip-shaped rubber members 58 in the tire radial direction TR.

[0082] (Third embodiment) Fig. 9 shows a pneumatic tire 10 manufactured by the manufacturing method of the third embodiment, and Fig. 10 shows a green tire 50 of the third embodiment and a tire vulcanization mold 80. This third embodiment differs from the first embodiment in that the components of the belt-shaped rubber member 58 are changed and the winding order when molding the green tire 50 is changed.

[0083] Specifically, the band-shaped rubber member 58 shown in FIG. 10 is made of rubber whose composition is different from that of any of the base rubber 56, the cap rubber 57, and the sidewall rubber 59.

[0084] 9, on the outer side of the pneumatic tire 10 in the tire axial direction TA, the outermost portion 22a of the sidewall rubber layer 22 in the tire radial direction TR is disposed between the pad 18 and the base 20. On the outermost side of the tire axial direction TA, a rubber layer 35 made of a strip-shaped rubber member 58 is provided on the outer side of the sidewall rubber layer 22 in the tire radial direction TR.

[0085] 10, the outermost portion of the sidewall rubber 59 in the tire radial direction TR is wound between the pad rubber 54 and the base rubber 56. This is because the sidewall rubber 59 is turned up before the tread rubber 55 including the belt-shaped rubber member 58 is wound therearound.

[0086] After the turn-up, the tread rubber 55 with the belt-shaped rubber member 58 attached integrally thereto is wound around the tire. As a result, the belt-shaped rubber member 58 is wound around the outer side in the tire axial direction TA of the tire relative to a portion of the sidewall rubber 59 that is outer in the tire radial direction TR. Thereafter, as in the first embodiment, air is removed using a pressure roller (not shown) to complete the green tire 50, and the green tire 50 is vulcanized in a tire vulcanizing mold 80 to complete the pneumatic tire 10.

[0087] The second and third embodiments configured as described above can achieve the same functions and effects as the first embodiment. In the manufacturing method of the third embodiment, the sidewall rubber 59 and the belt-shaped rubber member 58 may be formed using rubber of the same composition. Also, in the manufacturing method of the third embodiment, the arrangement of the belt-shaped rubber member 58 in the tire radial direction TR can be changed as in the second embodiment.

[0088] The decoration is not limited to a configuration consisting of a protrusion with a bow-shaped cross section, but may have the cross-sectional shapes shown in the following fourth to eighth embodiments, or other cross-sectional shapes, and can be changed as needed.

[0089] (Fourth embodiment) FIG. 11 shows a pneumatic tire 10 manufactured by the manufacturing method of the fourth embodiment, and FIG. 12 shows a green tire 50 and a tire vulcanizing mold 80 of the fourth embodiment.

[0090] 11, the decoration 31B of the fourth embodiment is a recess recessed inward in the tire axial direction TA (toward the tire equator line CL) from the surface 30a of the buttress region 30. The decoration 31B has a bow-shaped cross section and extends in the tire circumferential direction TC to form an annular shape.

[0091] 12, molded portion 84B has a shape corresponding to the cross-sectional shape of ornament 31B shown in Fig. 11, and in this embodiment is formed by a protrusion (convex) having an arch-shaped cross section, extending into an annular groove. A continuous portion 84a of molded portion 84B, which continues to molded surface 83a, is a depression (concave) corresponding to edges 31a, 31b of ornament 31B shown in Fig. 11.

[0092] As in the first embodiment, the thickness t and length L1 of the belt-shaped rubber member 58 of this fourth embodiment are set based on the dimension (depth) S of the ornament 31B in the tire axial direction TA, the width W in the tire radial direction TR, and the cross-sectional shape. Specifically, when the cross-sectional shape of the ornament 31B is a bow-shaped recess, it is the same as the ornament 31A of the first embodiment, whose cross-sectional shape is a bow-shaped protrusion. In other words, the thickness t of the belt-shaped rubber member 58 is set to be 1.5 to 2.0 times the dimension S of the ornament 31B in the tire axial direction TA, and the length L1 of the upper side 58b of the belt-shaped rubber member 58 is set to be 0.75 to 1.25 times the width W of the ornament 31B in the tire radial direction TR.

[0093] In the case of decoration 31B consisting of a recess, the rubber tends to flow too much at the top of molded portion 84B, making the bottom of decoration 31B thinner. To prevent this problem, even in the case of decoration 31B consisting of a recess, a band-shaped rubber member 58 similar to that used in decoration 31A consisting of a protrusion is used.

[0094] In the fourth embodiment configured as described above, the amount of rubber at the bottom of the decoration 31B can be secured, preventing thin portions from occurring. Furthermore, the rubber can be sufficiently distributed in the recessed connection portion 84a shown in FIG. 12. Therefore, the decoration 31B can be reliably molded in the desired shape.

[0095] (Fifth embodiment) FIG. 13 shows a pneumatic tire 10 manufactured by the manufacturing method of the fifth embodiment, and FIG. 14 shows a green tire 50 and a tire vulcanization mold 80 of the fifth embodiment.

[0096] 13, the decoration 31C of the fifth embodiment is formed of a protrusion that protrudes outward in the tire axial direction TA from the surface 30a of the buttress region 30. The decoration 31C has a trapezoidal cross section and extends in the tire circumferential direction TC to form an annular shape.

[0097] 14, molded portion 84C is configured as a depression (concave) with a trapezoidal cross section corresponding to the cross-sectional shape of decoration 31C shown in Fig. 13, and extends into an annular groove. Continuous portion 84a of molded portion 84C, which continues to molded surface 83a, is an edge (convex) corresponding to edges 31a, 31b of decoration 31C shown in Fig. 13.

[0098] When the decoration 31C is a protrusion with a trapezoidal cross section, the thickness t of the strip-shaped rubber member 58 shown in Figure 5 is set to be 1.5 to 2.0 times the dimension (thickness) S of the decoration 31C in the tire axial direction TA, and the length L1 of the upper edge 58b of the strip-shaped rubber member 58 is set to be 0.75 to 1.25 times the width W of the decoration 31C in the tire radial direction TR.

[0099] (Sixth embodiment) FIG. 15 shows a pneumatic tire 10 manufactured by the manufacturing method of the sixth embodiment, and FIG. 16 shows a green tire 50 and a tire vulcanization mold 80 of the sixth embodiment.

[0100] 15, the decoration 31D of the sixth embodiment is a recess recessed inward in the tire axial direction TA from the surface 30a of the buttress region 30. The decoration 31D has a trapezoidal cross section and extends in the tire circumferential direction TC to form an annular shape.

[0101] 16, molded portion 84D is configured with a protrusion (convex) having a trapezoidal cross section corresponding to the cross section of decoration 31D shown in Fig. 15, and extends into an annular groove. A continuous portion 84a of molded portion 84D that continues to molded surface 83a is a depression (concave) that corresponds to edges 31a, 31b of decoration 31D shown in Fig. 15.

[0102] When the decoration 31D is a recess with a trapezoidal cross section, the thickness t of the strip-shaped rubber member 58 shown in Figure 5 is set to be 1.5 to 2.0 times the dimension (depth) S of the decoration 31D in the tire axial direction TA, and the length L1 of the upper edge 58b of the strip-shaped rubber member 58 is set to be 0.75 to 1.25 times the width W of the decoration 31D in the tire radial direction TR.

[0103] (Seventh embodiment) FIG. 17 shows a pneumatic tire 10 manufactured by the manufacturing method of the seventh embodiment, and FIG. 18 shows a green tire 50 and a tire vulcanization mold 80 of the seventh embodiment.

[0104] 17, the decoration 31E of the seventh embodiment is formed of a protrusion that protrudes outward in the tire axial direction TA from the surface 30a of the buttress region 30. The decoration 31E has a triangular cross section and extends in the tire circumferential direction TC to form an annular shape.

[0105] 18, molded portion 84E is configured as a depression (concave) with a triangular cross section corresponding to the cross-sectional shape of decoration 31E shown in Fig. 17, and extends into an annular groove. Continuous portion 84a of molded portion 84E, which continues to molded surface 83a, is an edge (convex) corresponding to edges 31a, 31b of decoration 31E shown in Fig. 17.

[0106] When the decoration 31E is a protrusion with a triangular cross section, the thickness t and length L1 of the belt-shaped rubber member 58 shown in FIG. 5 are set to satisfy the following.

[0107] [Number 5] 1.0S≦t≦1.5S 0.75W≦L1≦1.25W S: Dimension of decoration in tire axial direction W: Width of decoration in the radial direction of the tire t: Thickness of the rubber strip L1: Length of the top edge of the belt-shaped rubber member

[0108] The ornament 31E with a triangular cross section shown in Fig. 17 has a smaller cross-sectional area than the ornament 31A with a bow cross section shown in Fig. 2 and the ornament 31C with a trapezoid cross section shown in Fig. 13. Therefore, the amount of rubber required to mold the ornament 31E with a triangular cross section is less than the amount of rubber required to mold the ornament 31A with a bow cross section and the ornament 31C with a trapezoid cross section. Therefore, the thickness t of the belt-shaped rubber member 58 is set to be 1.0 to 1.5 times the dimension (thickness) S of the ornament 31E in the tire axial direction TA.

[0109] (Eighth embodiment) FIG. 19 shows a pneumatic tire 10 manufactured by the manufacturing method of the eighth embodiment, and FIG. 20 shows a green tire 50 and a tire vulcanizing mold 80 of the eighth embodiment.

[0110] 19, the decoration 31F of the eighth embodiment is a recess recessed inward in the tire axial direction TA from the surface 30a of the buttress region 30. The decoration 31F has a triangular cross section and extends in the tire circumferential direction TC to form an annular shape.

[0111] 20, molded portion 84F is configured with a protrusion (convex) having a triangular cross section corresponding to the cross section of ornament 31F shown in Fig. 19, and extends into an annular groove. A continuous portion 84a of molded portion 84F, which continues to molded surface 83a, is a depression (concave) corresponding to edges 31a, 31b of ornament 31F shown in Fig. 19.

[0112] When the decoration 31F is a recess with a triangular cross section, the thickness t of the strip-shaped rubber member 58 shown in Figure 5 is set to be 1.0 to 1.5 times the dimension (depth) S of the decoration 31F in the tire axial direction TA, and the length L1 of the upper edge 58b of the strip-shaped rubber member 58 is set to be 0.75 to 1.25 times the width W of the decoration 31F in the tire radial direction TR.

[0113] The fourth to eighth embodiments configured as described above can achieve the same functions and effects as the first embodiment. Furthermore, in the manufacturing methods of the fourth to eighth embodiments, the arrangement of the belt-shaped rubber member 58 in the tire radial direction TR may be changed, as in the second embodiment, in order to change the molding position of the decoration in the tire radial direction TR. Furthermore, as in the third embodiment, the sidewall rubber 59 and the belt-shaped rubber member 58 may be molded using rubbers of different compositions, or the arrangement of the belt-shaped rubber member 58 relative to the sidewall rubber 59 may be changed.

[0114] Furthermore, the present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible.

[0115] For example, as shown in Fig. 21 , the decoration 31 may be a plurality of protrusions provided at intervals in the tire circumferential direction TC. Alternatively, the decoration 31 may be a plurality of recesses provided at intervals in the tire circumferential direction TC. Alternatively, the decoration 31 may be discontinuously provided annular protrusions or discontinuously provided annular recesses.

[0116] The band-shaped rubber member 58 may be wound around the tread rubber 55 by itself without being attached to the tread rubber 55. [Explanation of symbols]

[0117] 10 Pneumatic tires 11 Tread 11a Main groove 11b Tread 11c outer end 12 Sidewall 12a Maximum width position 14 Carcass 15 Inner liner 16 Belt Layer 17A, 17B, 17C Belt 18 pads 19 Tread rubber layer 20 base 21 Cap 22 Sidewall rubber layer 22a outer part 22b Inner part 30 Buttress area 30a surface 31, 31A~31F Decoration 31a Common Marriage 31b outer edge 35 rubber layer 50 Green Tire 50a Decorative molding area 51 Carcass ply 52 Inner liner rubber 53 Belt ply 54 Pad Rubber 55 Tread rubber 56 Base rubber 56a bottom edge 56b Top 56c side 57 Cap rubber 57a bottom edge 57b Top 57c side 58 Strip-shaped rubber member 58a bottom edge 58b Top 58c 1st side 58d 2nd side 58e Chamfer 59 Sidewall rubber 80 Tire curing mold 81 Sector Mold 82 sectors 82a Molding surface 82b protrusion 82c corner 83 Side mold 83a Molding surface 84A~84F Molding part 84a Continuous section 85 Brada TA Tire axial direction TR Tire radial direction TC: Tire Circumferential Direction CL tire equator line

Claims

1. a belt-shaped rubber member having a trapezoidal cross section, the thickness from the lower edge to the upper edge of which is set in accordance with the dimension in the tire axial direction and the cross-sectional shape of a decoration, which is a protrusion or recess provided in a buttress region on the outer side of the sidewall in the tire radial direction, and the length of the upper edge of which is set in accordance with the width in the tire radial direction and the cross-sectional shape of the decoration; forming a green tire by disposing the belt-shaped rubber member in a region where the decoration is to be molded with respect to a sidewall rubber constituting the sidewall; the green tire is vulcanized and molded using a tire vulcanization mold having a molding portion corresponding to a cross-sectional shape of the decoration, When the cross-sectional shape of the decoration is arched or trapezoidal, the thickness and length of the belt-shaped rubber member satisfy the following. 1.5S≦t≦2.0S 0.75W≦L1≦1.25W S: Dimension of decoration in tire axial direction W: width of decoration in the tire radial direction t: thickness of the belt-shaped rubber member L1: Length of the upper side of the belt-shaped rubber member

2. A band-shaped rubber member having a trapezoidal cross section, the thickness from the lower edge to the upper edge of which is set according to the axial dimension and cross-sectional shape of a decoration, which is a protrusion or depression provided in the buttress region on the outer side of the sidewall in the tire radial direction, and the length of the upper edge of which is set according to the radial width and cross-sectional shape of the decoration, is prepared; forming a green tire by disposing the belt-shaped rubber member in a region where the decoration is to be molded with respect to a sidewall rubber constituting the sidewall; the green tire is vulcanized and molded using a tire vulcanization mold having a molding portion corresponding to a cross-sectional shape of the decoration, a thickness of the belt-shaped rubber member and a length of the belt-shaped rubber member, the thickness and the length of the belt-shaped rubber member satisfying the following: 1.0S≦t≦1.5S 0.75W≦L1≦1.25W S: Dimension of decoration in tire axial direction W: width of decoration in the tire radial direction t: thickness of the belt-shaped rubber member L1: Length of the upper side of the belt-shaped rubber member

3. The length of the lower side of the belt-shaped rubber member is longer than the length of the upper side, 3. The method for manufacturing a pneumatic tire according to claim 1, wherein when the green tire is molded, the belt-shaped rubber member is wound around both sides of a tread rubber constituting a tread with the lower side attached to each side.

4. A band-shaped rubber member having a trapezoidal cross section, the thickness from the lower edge to the upper edge of which is set according to the axial dimension and cross-sectional shape of a decoration, which is a protrusion or depression provided in the buttress region on the outer side of the sidewall in the tire radial direction, and the length of the upper edge of which is set according to the radial width and cross-sectional shape of the decoration, is prepared; forming a green tire by disposing the belt-shaped rubber member in a region where the decoration is to be molded with respect to a sidewall rubber constituting the sidewall; the green tire is vulcanized and molded using a tire vulcanization mold having a molding portion corresponding to a cross-sectional shape of the decoration, The length of the lower side of the belt-shaped rubber member is longer than the length of the upper side, In the method for manufacturing a pneumatic tire, when the green tire is molded, the belt-shaped rubber member is wound around the tread rubber constituting the tread with the lower side attached to both sides of the tread rubber.

5. A method for manufacturing a pneumatic tire described in any one of claims 1 to 4, wherein, when molding the green tire, after winding the strip-shaped rubber member, the sidewall rubber is wound so that a portion of the sidewall rubber overlaps the outside of the strip-shaped rubber member in the tire axial direction.

6. A band-shaped rubber member having a trapezoidal cross section, the thickness from the lower edge to the upper edge of which is set according to the axial dimension and cross-sectional shape of a decoration, which is a protrusion or depression provided in the buttress region on the outer side of the sidewall in the tire radial direction, and the length of the upper edge of which is set according to the radial width and cross-sectional shape of the decoration, is prepared; forming a green tire by disposing the belt-shaped rubber member in a region where the decoration is to be molded with respect to a sidewall rubber constituting the sidewall; the green tire is vulcanized and molded using a tire vulcanization mold having a molding portion corresponding to a cross-sectional shape of the decoration, In the method for manufacturing a pneumatic tire, when molding the green tire, after winding the belt-shaped rubber member, the sidewall rubber is wound so that a portion of the sidewall rubber overlaps the outer side of the belt-shaped rubber member in the tire axial direction.

7. The length of the first side edge of the band-shaped rubber member is longer than the length of the second side edge, 7. The method for manufacturing a pneumatic tire according to claim 1, wherein, when the green tire is molded, the belt-shaped rubber member is wound such that the first side edge is positioned further outward in the tire radial direction than the second side edge.

8. A band-shaped rubber member having a trapezoidal cross section, the thickness from the lower edge to the upper edge of which is set according to the axial dimension and cross-sectional shape of a decoration, which is a protrusion or depression provided in the buttress region on the outer side of the sidewall in the tire radial direction, and the length of the upper edge of which is set according to the radial width and cross-sectional shape of the decoration, is prepared; forming a green tire by disposing the belt-shaped rubber member in a region where the decoration is to be molded with respect to a sidewall rubber constituting the sidewall; the green tire is vulcanized and molded using a tire vulcanization mold having a molding portion corresponding to a cross-sectional shape of the decoration, The length of the first side edge of the belt-shaped rubber member is longer than the length of the second side edge thereof, When the green tire is molded, the belt-shaped rubber member is wound so that the first side edge is positioned further outward in the tire radial direction than the second side edge.

9. A method for manufacturing a pneumatic tire described in any one of claims 1 to 4 and 8, wherein, when molding the green tire, the strip-shaped rubber member is wrapped around the outside of the tire axial direction of the outer portion of the sidewall rubber in the tire radial direction.

10. 10. The method for manufacturing a pneumatic tire according to claim 1, wherein, when a radial range of the buttress region from a maximum width position of the sidewall that protrudes furthest outward in the tire axial direction to an outer edge of a tread surface that is positioned outermost in the tire axial direction is defined as 1, the decoration is molded in a range of 0.3 to 0.8 based on the maximum width position.

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