JP2010280114A - Method of manufacturing pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a pneumatic tire which enables a high quality pneumatic tire to be stably manufactured. <P>SOLUTION: This method of manufacturing the pneumatic tire includes: (1) a process to form a bead 8 which includes a ring-like core 24 and an apex 26 of which cross section forms a tapered shape wherein, the apex 26 includes a bottom surface 38 being contacted with the core 24 and a side surface 42 extending toward a pointed end 46 from the bottom surface 38 and further, a notch 48 provided in the side surface 42; (2) a process to combine the bead 8 to a carcass ply wound around with a former into a cylindrical shape; (3) a process to push the apex 26 of the bead 8 downward to fold back the carcass ply around the core 24, (4) a process to obtain a raw cover by combining a tread and a sidewall on the outside of the carcass ply; and (5) a process to pressurize and heat the raw cover inside a mold. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a pneumatic tire. Specifically, the present invention relates to an improvement in a molding process of a raw cover (also referred to as an uncrosslinked tire).

  A pneumatic tire is configured by combining a number of members. The tire includes, for example, a pair of beads and a carcass bridged between the two beads.

  The bead includes a core and an apex that extends radially outward from the core. The core is formed by winding a non-stretchable wire (typically a steel wire). Apex is made of a crosslinked rubber. The carcass is composed of a carcass ply including a large number of cords arranged in parallel.

  In the tire manufacturing method, the apex is molded by extruding a rubber composition. This apex is combined with the core to obtain a ring-shaped bead.

  The bead is combined with a carcass ply wound around a former and formed into a cylindrical shape. The apex is pushed down inward and is in close contact with the carcass ply. The carcass ply is folded around the core. Members such as treads and sidewalls are further combined to obtain a raw cover. And this raw cover is pressurized and heated in a mold, and a tire is obtained.

  In order to stably manufacture a high-quality tire, various studies have been made on each process included in the tire manufacturing method. An example of this study is disclosed in Japanese Patent Laid-Open No. 2006-35948. In the manufacturing method described in this publication, convex ribs are provided on the contact surface of the apex with the core to prevent peeling of the apex from the core in the bead formation process.

JP 2006-35948 A

  Apex can contribute to the rigidity of the sidewall portion of the tire. From the viewpoint of handling stability, a high and hard apex is adopted. A high-hardness apex is unlikely to collapse during the carcass ply folding process. For this reason, the adhesion between the apex and the carcass ply is insufficient, and air may remain between the two. The remaining air affects the tire quality. With this manufacturing method, it is difficult to stably manufacture high-quality tires.

  An object of the present invention is to provide a method for manufacturing a pneumatic tire capable of stably manufacturing a high-quality pneumatic tire.

A method for manufacturing a pneumatic tire according to the present invention includes:
(1) It has a ring-shaped core and an apex whose section has a tapered shape, and the apex has a bottom surface in contact with the core and a side surface extending from the bottom surface toward the tip. A step of forming a bead having a notch on the side surface,
(2) a step of combining this bead with a carcass ply wound around a former and formed into a cylindrical shape;
(3) a step in which the apex of the bead is pushed down and the carcass ply is folded around the core;
(4) a step of obtaining a raw cover by combining a tread and a sidewall on the outside of the carcass ply;
(5) The raw cover includes a step of pressing and heating in the mold. In this manufacturing method, the ratio of the height from the bottom surface to the position indicating the maximum depth of the notch to the apex height from the bottom surface to the apex of the apex is 1/6 or more and 1/2 or less. It is. The ratio of the maximum depth of the notch to the width of the apex at the position indicating the maximum depth of the notch is not less than 1/4 and not more than 5/8. The maximum width of this notch is 2.0 mm or more and 3.0 mm or less.

  Preferably, in the method for manufacturing a pneumatic tire, the apex height is 20 mm or more and 65 mm or less. Preferably, the hardness of the apex is 75 or more and 97 or less.

  In the method for manufacturing a pneumatic tire according to the present invention, the apex is provided with a notch. This apex is easily pushed down in the carcass ply folding process. This notch promotes contact between the apex and the carcass ply. For this reason, remaining of air between the apex and the carcass ply is suppressed. According to this manufacturing method, defective air remaining in the tire can be effectively prevented, so that a high-quality tire is stably manufactured.

FIG. 1 is a cross-sectional view illustrating a part of a pneumatic tire manufactured by a manufacturing method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an apex formed by an extruder. FIG. 3 is a cross-sectional perspective view showing a part of a bead formed using the apex of FIG. 2. FIG. 4 is a schematic view illustrating a part of the formation state of the raw cover.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  The pneumatic tire 2 shown in FIG. 1 includes a tread 4, a sidewall 6, a bead 8, a carcass 10, a belt 12, a band 14, an inner liner 16 and a chafer 18. The tire 2 is a tubeless type. The tire 2 is mounted on a passenger car. In FIG. 1, the horizontal direction is the axial direction, the vertical direction is the radial direction, and the direction perpendicular to the paper surface is the circumferential direction. The tire 2 has a substantially left-right symmetric shape centered on a one-dot chain line CL in FIG. This alternate long and short dash line CL represents the equator plane of the tire 2.

  The tread 4 is made of a crosslinked rubber having excellent wear resistance. The tread 4 has a shape protruding outward in the radial direction. The tread 4 includes a tread surface 20. The tread surface 20 is in contact with the road surface. A groove 22 is carved in the tread surface 20. The groove 22 forms a tread pattern.

  The sidewall 6 extends substantially inward in the radial direction from the end of the tread 4. The sidewall 6 is made of a crosslinked rubber. The sidewall 6 absorbs an impact from the road surface by bending. Furthermore, the sidewall 6 prevents the carcass 10 from being damaged.

  The bead 8 is located substantially inward of the sidewall 6 in the radial direction. The bead 8 has a ring shape. The bead 8 includes a core 24 and an apex 26 that extends radially outward from the core 24. The apex 26 is tapered outward in the radial direction.

  The carcass 10 includes a carcass ply 28. The carcass ply 28 is bridged between the beads 8 on both sides. The carcass ply 28 extends along the inside of the tread 4 and the sidewall 6. The carcass ply 28 is folded around the core 24 from the inner side to the outer side in the axial direction. The end 30 of the folded carcass ply 28 is located on the radially outer side than the end 32 located on the radially outer side of the apex 26. Although not shown, the carcass ply 28 includes a plurality of cords arranged in parallel and a topping rubber. The carcass 10 has a radial structure.

  The belt 12 is located on the radially outer side of the carcass 10. The belt 12 is laminated with the carcass 10. The belt 12 reinforces the carcass 10. The belt 12 includes an inner layer 34 and an outer layer 36. Although not shown, each of the inner layer 34 and the outer layer 36 is composed of a large number of cords arranged in parallel and a topping rubber. Each cord is inclined with respect to the equator plane. The cord inclination direction of the inner layer 34 is opposite to the cord inclination direction of the outer layer 36.

  The band 14 covers the belt 12. Although not shown, the band 14 is composed of a cord and a topping rubber. The cord extends substantially in the circumferential direction and is wound spirally. The band 14 has a so-called jointless structure.

  In the tire 2, the apex 26 constituting the bead 8 is made of a crosslinked rubber. Although not shown, in the method for manufacturing the tire 2, an extruder is used in the step of forming the apex 26. A die plate is attached to the head of the extruder. The die plate forms a discharge port having a predetermined shape. In this step, the apex 26 is formed by discharging the rubber composition charged into the extruder from the discharge port.

  FIG. 2 is a cross-sectional view showing an apex 26 formed by an extruder. In FIG. 2, the direction perpendicular to the paper surface is the extrusion direction of the apex 26. FIG. 2 shows the apex 26 immediately after ejection. The cross-sectional shape of the apex 26 shown in FIG. 2 is equivalent to the shape of the discharge port provided in the extruder.

  As shown in the drawing, the cross section of the apex 26 has a tapered shape. The apex 26 includes a bottom surface 38, a first side surface 40, and a second side surface 42. The bottom surface 38 is flat. The bottom surface 38 extends in the extrusion direction. This bottom surface 38 is in contact with the core 24. In consideration of adhesiveness with the core 24, the bottom surface 38 may be formed of a surface including irregularities. The first side surface 40 extends from one long edge 44 a of the bottom surface 38 toward the tip 46 of the apex 26. The first side surface 40 is flat. The second side surface 42 extends from the other long edge 44 b of the bottom surface 38 toward the tip 46. The second side surface 42 has a notch 48.

  The notch 48 is a recessed portion of the second side surface 42. In this manufacturing method, the portion of the second side surface 42 other than the notch 48 is flat. The notch 48 extends in the extrusion direction of the apex 26. In the second side surface 42, the notch 48 is located between the bottom surface 38 and the tip 46. In other words, the notch 48 is located in the middle of the apex 26.

  In FIG. 2, what is indicated by a point PA is the edge of the notch 48. What is indicated by a point PB is the innermost end of the notch 48. This notch 48 indicates the maximum depth at this point PB. This point PB is a position indicating the maximum depth of the notch 48. As shown in the drawing, the notch 48 is configured such that its width gradually decreases from the point PA toward the point PB. The cross-sectional shape of the notch 48 is a triangle. This notch 48 shows the maximum width at this point PA.

  Although not shown in figure, the bottom face of the discharge port provided in the extruder is provided with a ridge having a triangular cross section at a position corresponding to the position of the notch 48 of the apex 26. This ridge protrudes from the bottom surface. This ridge scrapes off a part of the rubber composition passing through the discharge port. Therefore, in this manufacturing method, the notch 48 is formed by the rubber composition passing through the discharge port. The cross-sectional shape of this ridge is the same as the shape of the notch 48.

  In this manufacturing method, the apex 26 is combined with the core 24. By this combination, the bead 8 is formed.

  FIG. 3 is a cross-sectional perspective view showing a part of the bead 8 formed using the apex 26 of FIG. In FIG. 3, the double arrow X corresponds to the axial direction of the tire 2. A double arrow Y corresponds to the radial direction of the tire 2. A double arrow Z corresponds to the circumferential direction of the tire 2. This circumferential direction also corresponds to the extrusion direction of the apex 26.

  The core 24 constituting the bead 8 is formed by winding a non-stretchable wire 50 (typically a steel wire). The wire 50 extends in the circumferential direction. The core 24 has a ring shape. In this manufacturing method, the apex 26 is combined with the core 24 at the bottom surface 38 while the apex 26 is formed by an extruder. The beads 8 formed in this way are supplied to the former together with members such as the carcass ply 28, the sidewall 6, and the tread 4. In this former, these members are combined to form a raw cover.

  FIG. 4 is a schematic diagram showing a part of the formation state of the raw cover 52. In FIG. 4, the former 54, the carcass ply 28 and a part of the bead 8 are shown. In FIG. 4, the left-right direction is the axial direction of the former 54. The vertical direction is the radial direction of the former 54. The direction perpendicular to the paper surface is the circumferential direction of the former 54. FIG. 4 shows the raw cover 52 in the middle of formation.

  The former 54 has a substantially cylindrical shape. The former 54 includes a main body 56 and a movable portion 58. Although not shown, the main body 56 includes a plurality of segments. The main body 56 is configured to be able to expand the diameter. The movable portion 58 is located outside the main body 56 in the axial direction. The outer diameter of the movable portion 58 is smaller than that of the main body 56. The movable portion 58 is configured to move inward in the axial direction when the diameter of the main body 56 is increased.

  The carcass ply 28 is wound around the former 54. The carcass ply 28 has a cylindrical shape. The bead 8 is located outside the carcass ply 28. The bead 8 is located on the outer side in the radial direction of the movable portion 58 on the outer side in the axial direction of the main body 56. The main body 56 prevents the bead 8 from sliding inward in the axial direction. Thereby, the position of the bead 8 is fixed. The bead 8 is fitted to a former 54 around which the carcass ply 28 is wound so that a notch 48 provided on the second side surface 42 of the apex 26 is positioned on the inner side in the axial direction.

  In this manufacturing method, the bead 8 is combined with the carcass ply 28 wound around the former 54 and formed into a cylindrical shape. In this combination, the bead 8 is slid inward with the notch 48 inward. When the bead 8 reaches a predetermined position, the apex 26 that constitutes the bead 8 is pushed down inward in the axial direction, and the second side surface 42 abuts against the carcass ply 28. The carcass ply 28 is folded around the core 24 and abuts on the first side surface 40 of the apex 26. In this manufacturing method, the bead 8 is wrapped in the carcass ply 28 in the folding process of the carcass ply 28. In FIG. 4, a two-dot chain line L <b> 1 is an imaginary line in which the apex 26 in a tilted state is shown.

  In this manufacturing method, after the carcass ply 28 is folded, the movable portion 58 is moved inward in the axial direction while the diameter of the main body 56 of the former 54 is expanded, and the shape of the carcass ply 28 is adjusted. Members such as the sidewall 6 and the tread 4 are further combined to obtain the raw cover 52. The raw cover 52 is put into a mold held at a predetermined temperature. The raw cover 52 is sandwiched and pressed between the cavity surface of the mold and the outer surface of the bladder. The raw cover 52 is heated by heat conduction from the bladder and the mold. While the rubber composition of the raw cover 52 flows by the pressurization and heating, the rubber composition causes a crosslinking reaction, and the tire 2 is obtained.

  In this manufacturing method, a notch 48 is provided in the apex 26. The apex 26 is easily pushed down in the carcass ply 28 folding process. The notch 48 promotes contact between the second side surface 42 of the apex 26 and the carcass ply 28. This notch 48 can contribute to the adhesion between the second side surface 42 and the carcass ply 28. In this manufacturing method, air remaining between the apex 26 and the carcass ply 28 is suppressed. This manufacturing method can effectively prevent poor air remaining in the tire 2. According to this manufacturing method, the high-quality tire 2 is stably manufactured. This manufacturing method is excellent in productivity.

  As described above, in the bead 8 combined with the carcass ply 28, the notch 48 of the apex 26 is located on the inner side in the axial direction. The apex 26 tends to fall inward. The notch 48 promotes contact between the second side surface 42 and the carcass ply 28. This notch 48 can contribute to the adhesion between the second side surface 42 and the carcass ply 28. In this manufacturing method, air remaining between the apex 26 and the carcass ply 28 is suppressed. This manufacturing method can effectively prevent poor air remaining in the tire 2. According to this manufacturing method, the high-quality tire 2 is stably manufactured.

  As shown in FIG. 4, the notch 48 tapers from the inner side toward the outer side in the axial direction. The apex 26 tends to fall inward. The notch 48 promotes contact between the second side surface 42 and the carcass ply 28. This notch 48 can contribute to the adhesion between the second side surface 42 and the carcass ply 28. In this manufacturing method, air remaining between the apex 26 and the carcass ply 28 is suppressed. This manufacturing method can effectively prevent poor air remaining in the tire 2. According to this manufacturing method, the high-quality tire 2 is stably manufactured.

  As will be described later, in this manufacturing method, the position, size, and the like of the notch 48 provided in the apex 26 are appropriately adjusted. The apex 26 is easily pushed down. The notch 48 promotes contact between the second side surface 42 and the carcass ply 28. This notch 48 can contribute to the adhesion between the second side surface 42 and the carcass ply 28. In this manufacturing method, air remaining between the apex 26 and the carcass ply 28 is suppressed. This manufacturing method can effectively prevent poor air remaining in the tire 2. According to this manufacturing method, the high-quality tire 2 is stably manufactured.

  In this manufacturing method, since the notch 48 is provided in the apex 26, the apex 26 is easily pushed down even if the apex 26 having high hardness is employed. This notch 48 can effectively prevent the remaining air in the tire 2 having the high hardness apex 26. The high hardness apex 26 can contribute to the rigidity of the tire 2. The tire 2 is excellent in handling stability. Therefore, according to this manufacturing method, the tire 2 excellent in steering stability can be manufactured stably.

  In this manufacturing method, the hardness of the apex 26 may be 75 or more or 80 or more from the viewpoint of steering stability of the obtained tire 2. From the viewpoint of preventing the tire 2 from being excessively rigid and maintaining excellent riding comfort, the hardness is preferably 97 or less, and more preferably 90 or less. In the present invention, the hardness is measured with a type A durometer according to “JIS K 6253”. This hardness is measured under conditions where the temperature is 23 ° C. For this measurement, a test piece formed by crosslinking the rubber composition constituting the apex 26 is used. This test piece is obtained by holding the rubber composition in a mold having a temperature of 160 ° C. for 10 minutes.

  In FIG. 2, the double arrow WB is the maximum width of the notch 48. The maximum width WB of the notch 48 is obtained by measuring the distance from one edge PA to the other edge PA. A two-dot chain line L2 is an imaginary line representing the second side surface 42 when it is assumed that the second side surface 42 of the apex 26 has no notch 48. The double arrow DB is the maximum depth of the notch 48. The maximum depth DB is obtained by measuring the distance from the virtual line L2 to the position PB at which the notch 48 has the maximum depth. The solid line L3 is a straight line that passes through the maximum depth position PB and is orthogonal to the virtual line L2. A point PC is an intersection of the solid line L3 and the first side surface 40. A double-headed arrow DA represents the length from the virtual line L2 to the intersection point PC. This length DA is the width of the apex 26 at the maximum depth position PB. A double-headed arrow HA represents the length from the bottom surface 38 of the apex 26 to the tip 46 thereof. This length HA is the apex height. A double-headed arrow HB represents the length from the bottom surface 38 to the point PB. This length HB is the height from the bottom surface 38 to the maximum depth position PB.

  In this manufacturing method, the ratio of the height HB to the apex height HA is 1/6 or more and 1/2 or less. By setting this ratio to 1/6 or less, the notch 48 can effectively contribute to the fall of the apex 26 in the folding process of the carcass ply 28. Since the apex 26 tends to fall down, the contact between the apex 26 and the carcass ply 28 is promoted. Since the remaining of air between the apex 26 and the carcass ply 28 is suppressed, defective air remaining in the manufactured tire 2 can be effectively prevented. This manufacturing method can manufacture the high-quality tire 2 stably. In this respect, the ratio is more preferably equal to or greater than 0.17. Similarly, in the apex 26 in which this ratio is set to ½ or less, the notch 48 can effectively contribute to the fall of the apex 26 in the folding process of the carcass ply 28. Since the apex 26 tends to fall down, the contact between the apex 26 and the carcass ply 28 is promoted. Since the remaining of air between the apex 26 and the carcass ply 28 is suppressed, defective air remaining in the manufactured tire 2 can be effectively prevented. This manufacturing method can manufacture the high-quality tire 2 stably. In this respect, the ratio is more preferably equal to or less than 0.33.

  The apex height HA is preferably 20 mm or greater and 65 mm or less. The apex 26 in which the height HA is set to 20 mm or more is likely to fall down. The apex 26 can effectively contribute to the steering stability of the tire 2. From this viewpoint, the height HA is more preferably 30 mm or more. By setting the height to 65 mm or less, the influence of the apex 26 on the ride comfort is suppressed. From this viewpoint, the height HA is more preferably 60 mm or less.

  In this manufacturing method, the ratio of the maximum depth DB to the width DA is not less than 1/4 and not more than 5/8. By setting this ratio to ¼ or more, the notch 48 can effectively contribute to the fall of the apex 26 in the folding process of the carcass ply 28. Since the apex 26 tends to fall down, the contact between the apex 26 and the carcass ply 28 is promoted. Since the remaining of air between the apex 26 and the carcass ply 28 is suppressed, defective air remaining in the manufactured tire 2 can be effectively prevented. This manufacturing method can manufacture the high-quality tire 2 stably. In this respect, the ratio is more preferably equal to or greater than 0.30, and still more preferably equal to or greater than 0.38. By setting this ratio to 5/8 or less, the extrudability of the apex 26 is appropriately maintained. In this respect, the ratio is more preferably equal to or less than 0.50.

  The maximum depth DB is preferably 2 mm or more and 5 mm or less. By setting the maximum depth DB to 2 mm or more, the notch 48 can effectively contribute to the fall of the apex 26 in the folding process of the carcass ply 28. Since the apex 26 tends to fall down, the contact between the apex 26 and the carcass ply 28 is promoted. Since the remaining of air between the apex 26 and the carcass ply 28 is suppressed, defective air remaining in the manufactured tire 2 can be effectively prevented. This manufacturing method can manufacture the high-quality tire 2 stably. In this respect, the maximum depth DB is more preferably 3 mm or more. By setting the maximum depth DB to 5 mm or less, the extrudability of the apex 26 is appropriately maintained. From this viewpoint, the maximum depth DB is more preferably 4 mm or less.

  In this manufacturing method, the maximum width WB of the notch 48 is 2.0 mm or greater and 3.0 mm or less. By setting the maximum width WB to 2.0 mm or more, the notch 48 can effectively contribute to the fall of the apex 26 in the folding process of the carcass ply 28. Since the apex 26 tends to fall down, the contact between the apex 26 and the carcass ply 28 is promoted. Since the remaining of air between the apex 26 and the carcass ply 28 is suppressed, defective air remaining in the manufactured tire 2 can be effectively prevented. This manufacturing method can manufacture the high-quality tire 2 stably. From this viewpoint, the maximum width WB is more preferably 2.5 mm or more. By setting the maximum width WB to 3.0 mm or less, the extrudability of the apex 26 is appropriately maintained. According to this manufacturing method, the high-quality tire 2 can be manufactured stably.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example 1]
A raw cover was formed using the apex shown in FIG. 2, and 1000 tires (tire size: 285 / 65R17) shown in FIG. 1 were produced from the raw cover. This apex was joined to the core at the bottom. This apex has a notch in the middle of its second side. The maximum width WB of this notch was 2.5 mm. The maximum depth DB of this notch was 3 mm. The apex width DA at the position showing the maximum depth of the notch was 8 mm. The height HB from the bottom surface of the apex to the position PB indicating the maximum depth of the notch was 20 mm. The apex height HA was 60 mm. The apex had a hardness of 80.

[Example 4-6 and Comparative Example 4-5]
5000 tires were manufactured in the same manner as in Example 1 except that the ratio DB / DA was changed as shown in Tables 1 and 2 below by changing the maximum depth DB.

[Examples 3 and 7 and Comparative Examples 3 and 7]
2000 tires were manufactured in the same manner as in Example 1 except that the ratio HB / HA and the ratio DB / DA were changed as shown in Tables 1 and 2 below by changing the height HB and the width DA.

[Comparative Example 6]
2000 tires were manufactured in the same manner as in Example 1 except that the ratio HB / HA and ratio DB / DA were changed as shown in Tables 1 and 2 below by changing the height HB, width DA, and maximum depth DB. .

[Examples 2 and 8 and Comparative Examples 2 and 8]
2000 tires were manufactured in the same manner as in Example 1 except that the maximum width WB was as shown in Tables 1 and 2 below.

[Comparative Example 1]
10,000 tires were produced in the same manner as in Example 1 except that notches were not provided in the apex. Comparative Example 1 is a conventional tire manufacturing method.

[Tire appearance observation]
The appearance of the manufactured tire was visually observed to check for air remaining defects. The ratio of the number of tires in which defective air remaining in the manufactured tire is confirmed is shown in Tables 1 and 2 below as the remaining air occurrence rate. It represents that it is so favorable that this figure is small.

  As shown in Table 1 and Table 2, the manufacturing method of the example has higher evaluation than the manufacturing method of the comparative example. From this evaluation result, the superiority of the present invention is clear.

  The method described above can be applied to the manufacture of various tires.

2 ... tyre 4 ... tread 6 ... side wall 8 ... bead 10 ... carcass 12 ... belt 14 ... band 26 ... apex 28 ... carcass ply 38 ..Bottom surface 40 ... first side surface 42 ... second side surface 48 ... notch

Claims (3)

A ring-shaped core and an apex having a tapered cross section are provided. The apex includes a bottom surface that comes into contact with the core, and a side surface that extends from the bottom surface toward the tip. And a step of forming a bead having a notch on this side surface;
A process in which this bead is combined with a carcass ply wound around a former and formed into a cylindrical shape;
The bead apex is pushed down and the carcass ply is folded around the core;
A process of obtaining a raw cover by combining a tread and a sidewall on the outside of the carcass ply;
The raw cover includes a step of pressing and heating in the mold,
The ratio of the height from the bottom surface to the position indicating the maximum depth of the notch to the apex height from the bottom surface to the apex of the apex is 1/6 or more and 1/2 or less,
The ratio of the maximum depth of the notch to the width of the apex at the position indicating the maximum depth of the notch is ¼ or more and 5/8 or less,
The manufacturing method of the pneumatic tire whose maximum width of this notch is 2.0 mm or more and 3.0 mm or less.   The method for manufacturing a pneumatic tire according to claim 1, wherein the apex height is 20 mm or more and 65 mm or less.   The method for producing a pneumatic tire according to claim 1 or 2, wherein the hardness of the apex is 75 or more and 97 or less.

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