JP2009202471A - Method of manufacturing tire for heavy loading - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a tire 2 for heavy loading capable of improving productivity. <P>SOLUTION: The production method includes the steps of: (1) manufacturing an assembly ribbon 56 by joining the portion of an edge 66 of an inner liner 20 and that of an edge 68 of a side sheet 52; (2) manufacturing an assembly sheet by cutting the assembly ribbon 56; (3) feeding the assembly sheet to a former; (4) manufacturing a raw cover (non-crosslinking tire) by combining the assembly sheet with other members; and (5) pressurizing and heating the raw cover in a mold. In the step of manufacturing the assembly sheet, it is preferable to cut the assembly ribbon 56 using an ultrasonic cutter and further, the gradient angle of the cutting face of the assembly sheet is preferably ≥15° but ≤25°. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a heavy duty tire.

  In the tire manufacturing method, a raw cover (also referred to as an uncrosslinked tire) is put into a mold, and pressurized and heated. By this pressurization and heating, the rubber composition of the raw cover flows. The rubber composition causes a crosslinking reaction by heating, and a tire is obtained.

  In this manufacturing method, the raw cover is formed by combining a large number of rubber members. Specific examples of the rubber member include an inner liner, chafer, carcass ply, bead, sidewall, and tread. The process of forming the raw cover is referred to as a molding process.

Since the raw cover is a composite made up of a large number of rubber members, damage such as cracking and peeling occurs between the rubber members, which may impair the durability of the tire. From the viewpoint of improving durability, various studies have been made on the method of forming the raw cover. One example is disclosed in Japanese Patent Application Laid-Open No. 2002-18978.
JP 2002-18978 A

  In the molding step, a large number of rubber members having appropriate sizes are prepared by cutting, and these are bonded together while being arranged at appropriate positions. Since the number of rubber members included in the raw cover is large, it takes time to obtain a raw cover by bonding them together. This bonding time affects the productivity of the tire. In heavy-duty tires mounted on trucks, buses, etc., the number of rubber members constituting the tires is large, so the bonding time has a great influence on productivity.

  When an intermediate product is prepared by combining a plurality of rubber members constituting the raw cover in advance, the bonding time can be shortened. On the other hand, this intermediate product is invented. The occurrence of this inventory hinders tire productivity.

  An object of the present invention is to provide a method for manufacturing a heavy duty tire capable of improving productivity.

The method for manufacturing a heavy duty tire according to the present invention is as follows.
(1) The step of joining the edge portion of the inner liner and the edge portion of the side sheet to obtain an assembly ribbon;
(2) The assembly ribbon is cut to obtain an assembly sheet;
(3) a step of supplying the assembly sheet to a former;
(4) A process of obtaining a raw cover by combining other members with the assembly sheet;
(5) The raw cover includes a step of pressing and heating in the mold.

  Preferably, in this manufacturing method, in the step of obtaining the assembly sheet, the assembly ribbon is cut with an ultrasonic cutter.

  Preferably, in this manufacturing method, in the step of obtaining the assembly sheet, the inclination angle of the cut surface of the assembly sheet is 15 ° or more and 25 ° or less.

  Preferably, in this manufacturing method, in the step of obtaining the assembly ribbon, a joining width between the inner liner and the side sheet is 15 mm or more and 35 mm or less.

  An apparatus for manufacturing a heavy duty tire according to the present invention includes a pressure roller that can join an inner liner and a side sheet to form an assembly ribbon, a cutter that can cut the assembly ribbon to form an assembly sheet, and the assembly. And a former that can form a raw cover by combining other members with the sheet.

  In this manufacturing method, an assembly sheet obtained by cutting an assembly ribbon is supplied to a former and combined with other rubber members. This assembly sheet is not stored in stock. This manufacturing method does not inhibit productivity. In this manufacturing method, an assembly sheet in which an inner liner and a side sheet are joined in advance is used. In this manufacturing method, the number of rubber members combined in the former is small. This manufacturing method can contribute to shortening the formation time of the raw cover. Productivity can be improved by using this manufacturing method.

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

  FIG. 1 is a cross-sectional view showing a part of a heavy duty tire 2 obtained by a manufacturing method according to an embodiment of the present invention. In FIG. 1, the vertical direction is the radial direction, the horizontal direction is the axial 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 tire 2 includes a tread 4, a sidewall 6, a bead 8, a carcass 10, a belt 12, a reinforcing layer 14, a cover rubber 16, an inner sidewall 18, an inner liner 20, and a chafer 22. The tire 2 is a tubeless type. The tire 2 is attached to a truck, a bus or the like.

  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 24. The tread surface 24 is in contact with the road surface. A groove 26 is carved in the tread surface 24. The groove 26 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 includes a core 28, an apex 30 that extends radially outward from the core 28, and a packing rubber 32 that extends radially outward from the apex 30. The core 28 has a ring shape. The core 28 includes a plurality of non-stretchable wires (typically steel wires). The apex 30 is tapered outward in the radial direction. The apex 30 is made of a highly hard crosslinked rubber. The packing rubber 32 is tapered outward in the radial direction. The packing rubber 32 is soft. The packing rubber 32 relieves stress concentration at the end 34 of the carcass 10.

  The carcass 10 includes a carcass ply 36. The carcass ply 36 is bridged between the beads 8 on both sides, and extends along the inside of the tread 4 and the sidewall 6. The carcass ply 36 is folded around the core 28 from the inner side to the outer side in the axial direction.

  Although not shown, the carcass ply 36 includes a plurality of cords arranged in parallel and a topping rubber. The absolute value of the angle formed by each cord with respect to the equator plane is usually 70 ° to 90 °. In other words, the carcass 10 has a radial structure. The cord is made of steel.

  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 a first layer 38, a second layer 40, a third layer 42, and a fourth layer 44. Each of the first layer 38, the second layer 40, the third layer 42, and the fourth layer 44 is composed of a large number of cords arranged in parallel and a topping rubber. Each cord is made of steel. This cord is inclined with respect to the equator plane. The absolute value of the angle formed by this cord with respect to the equator plane is 15 ° to 70 °.

  The reinforcing layer 14 is wound around the core 28. The reinforcing layer 14 is laminated with the carcass ply 36. The reinforcing layer 14 includes a large number of cords arranged in parallel and a topping rubber. Each cord is made of steel. This reinforcing layer 14 is also called a steel filler. The reinforcing layer 14 contributes to the durability of the tire 2.

  The cover rubber 16 is located outside the packing rubber 32 in the axial direction. The cover rubber 16 is laminated on the carcass 10. An end 34 of the carcass ply 36 is covered with the cover rubber 16. The cover rubber 16 reduces the stress concentration on the end 34. One end 46 of the reinforcing layer 14 is also covered with the cover rubber 16. The cover rubber 16 reduces the stress concentration on the one end 46.

  The inner sidewall 18 is positioned on the inner side in the axial direction of the chafer 22 described later. The inner sidewall 18 is laminated on the chafer 22. The inner sidewall 18 is located outside the cover rubber 16 in the axial direction. The radially outer end 48 of the inner sidewall 18 is in contact with the packing rubber 32. The radially inner end 50 of the inner sidewall 18 is in contact with the reinforcing layer 14. The inner sidewall 18 is partially laminated with the reinforcing layer 14. The composition of the inner sidewall 18 is equivalent to the composition of the packing rubber 32. The inner sidewall 18 is soft. The inner sidewall 18 is interposed between the chafer 22 and the reinforcing layer 14. The inner sidewall 18 relieves stress between the chafer 22 and the reinforcing layer 14.

  The chafer 22 is located in the vicinity of the bead 8. The chafer 22 extends radially inward from the sidewall 6. The chafer 22 is partially laminated with the inner sidewall 18. When the tire 2 is incorporated into the rim, the chafer 22 comes into contact with the rim. By this contact, the vicinity of the bead 8 is protected. The chafer 22 is usually made of cloth and rubber impregnated in the cloth. A chafer 22 made of a single rubber may be used.

  The inner liner 20 is joined to the inner peripheral surface of the carcass 10. The inner liner 20 extends radially outward from the chafer 22. The inner liner 20 is bridged between the left and right chafers 22. The inner liner 20 is made of a crosslinked rubber. The inner liner 20 is made of rubber having excellent air shielding properties. The inner liner 20 plays a role of maintaining the internal pressure of the tire 2.

  In the tire 2, a portion including the chafer 22, the inner sidewall 18, and the sidewall 6 is referred to as a side seat 52.

  The tire 2 is manufactured as follows. First, the inner liner 20 is formed using an extruder and wound on the first reel. Next, a side sheet 52 composed of the chafer 22, the inner side wall 18 and the side wall 6 is formed by using an extruder and wound on the second reel. Two second reels around which the side sheets 52 are wound are prepared. Next, the second reel on which the side sheet 52 is wound is disposed on each side of the first reel on which the inner liner 20 is wound.

  2A is a plan view showing a part of the manufacturing apparatus 54 for the tire 2 of FIG. 1, and FIG. 2B is a front view thereof. The right side of the paper is the upstream side of the manufacturing apparatus 54, and the left side is the downstream side of the manufacturing apparatus 54. The manufacturing apparatus 54 shown in FIG. 2 can form an assembly ribbon 56 from the inner liner 20 and the pair of side sheets 52. In the manufacturing apparatus 54, the assembly ribbon 56 is conveyed in the direction indicated by the arrow line A.

  The manufacturing apparatus 54 includes a pressure roller 58 and a pair of guide rollers 60. The pressure roller 58 is located on the downstream side of the first reel 62 and the second reel 64. As shown in the drawing, the guide rollers 60 are arranged apart from each other in the width direction of the assembly ribbon 56. Each guide roller 60 is located between the pressure roller 58 and the second reel 64. In the manufacturing apparatus 54, the guide roller 60 is configured to be slidable in the width direction.

  In this manufacturing method, the inner liner 20 is pulled out from the first reel 62 in the transport direction. The side sheet 52 is pulled out from the second reel 64 in the transport direction. The drawn side sheet 52 is passed through the guide roller 60. Next, the edge 66 portion of the inner liner 20 is placed on the edge 68 portion of the side sheet 52 that has passed through the guide roller 60. In this manner, the edge 66 portion of the inner liner 20 overlaps the edge 68 portion of the side seat 52. Next, the pressure roller 58 is pressed against a portion where the inner liner 20 and the side sheet 52 overlap, and the inner liner 20 and the side sheet 52 are joined. By this joining, an assembly ribbon 56 is formed. In this manufacturing method, the inner liner 20 and the side sheet 52 are pulled out in this manner, and the edge 66 portion of the inner liner 20 and the edge 68 portion of the side sheet 52 are joined to obtain the assembly ribbon 56. It is done. The assembly ribbon 56 is conveyed in the direction indicated by the arrow line A and is cut by a predetermined length. In FIG. 2, an arrow line B is the forward rotation direction of the first reel 62. An arrow line C is the forward rotation direction of the second reel 64. An arrow line D is the forward rotation direction of the guide roller 60. The arrow line E is the normal rotation direction of the pressure roller 58.

  FIG. 3 is a plan view showing another part of the tire 2 manufacturing apparatus 54 of FIG. 1. In the drawing, the direction indicated by the arrow line A represents the transport direction of the assembly ribbon 56. The right side of the paper is the upstream side of the manufacturing apparatus 54, and the left side is the downstream side of the manufacturing apparatus 54.

  The manufacturing apparatus 54 further includes a cutter 70 and a conveyor 72. The cutter 70 cuts the assembly ribbon 56 to a predetermined length while moving from one end to the other end. By this cutting, an assembly sheet 74 is obtained. The assembly sheet 74 is conveyed to the next process using the conveyor 72. In the drawing, an arrow line F represents the moving direction of the cutter 70. This moving direction is also the cutting direction of the assembly ribbon 56.

  4A is a plan view showing still another part of the manufacturing apparatus 54 for the tire 2 in FIG. 1, and FIG. 4B is a front view thereof. In FIG. 4, the direction indicated by the arrow line A represents the conveyance direction of the assembly sheet 74. The right side of the paper is the upstream side of the manufacturing apparatus 54, and the left side is the downstream side of the manufacturing apparatus 54.

  The manufacturing apparatus 54 further includes a former 76. The former 76 includes a drum 78. The drum 78 can rotate. In FIG. 4, an arrow line G represents the normal rotation direction of the drum 78. The assembly sheet 74 supplied to the former 76 by the conveyor 72 is wound around the drum 78 while the drum 78 is rotated. In the drum 78, one cutting surface 80a of the assembly sheet 74 and the other cutting surface 80b are joined together, and the assembly sheet 74 is formed into a ring shape. In addition to the assembly sheet 74, many other rubber members are supplied to the former 76. These other rubber members are also wound around the drum 78 while the drum 78 is rotated. In this manufacturing method, these other rubber members are combined with the assembly sheet 74 to obtain a raw cover.

  FIG. 5 is a partial cross-sectional view showing the formation state of the raw cover. FIG. 5 shows a cross section of the rubber member laminated on the drum 78 along the axial direction of the drum 78. FIG. 5A shows a cross section of the assembly sheet 74. As shown in the drawing, side sheets 52 are disposed on both sides of the inner liner 20 in the axial direction. As described above, the side seat 52 includes the chafer 22, the inner sidewall 18, and the sidewall 6. Although not shown, the chafer 22 is located outside the inner liner 20 in the axial direction. The sidewall 6 is located further outside in the axial direction of the chafer 22. The inner sidewall 18 is laminated on the chafer 22 and extends inward in the axial direction from the boundary between the sidewall 6 and the chafer 22.

  FIG. 5B shows a state where the reinforcing layer 14 and the cover rubber 16 are combined with the assembly sheet 74. As shown, the reinforcing layer 14 is laminated on the outside of the assembly sheet 74. The reinforcing layer 14 extends inward in the axial direction from an overlapping portion 82 between the inner liner 20 and the side sheet 52. The cover rubber 16 is located in the vicinity of the axially outer end 84 of the reinforcing layer 14. A part of the cover rubber 16 is laminated outside the reinforcing layer 14.

  FIG. 5C shows a situation where the carcass ply 36 is further combined. As shown in the figure, the carcass ply 36 is laminated outside the cover rubber 16 and the reinforcing layer 14. The carcass ply 36 is bridged between the left and right cover rubbers 16.

  FIG. 5D shows a situation where the beads 8 are further combined. As shown in the figure, the bead 8 is laminated outside the carcass ply 36. The bead 8 is combined with another rubber member that is already combined with the former 76 so that the core 28 is located on the outer side in the axial direction. The core 28 is disposed at a position corresponding to the intermediate portion 86 of the reinforcing layer 14 in the axial direction.

  In this manufacturing method, when the beads 8 are combined, they are shaped and deformed from a cylindrical shape to a toroidal shape. Upon this deformation, the assembly sheet 74 is folded around the core 28 while the end 88 of the assembly sheet 74 is lifted. Furthermore, other rubber members such as the tread 4 are combined to complete the raw cover. This raw cover is subjected to a vulcanization process.

  In this manufacturing method, the raw cover is put into a mold opened in the vulcanization process. The raw cover is pressurized and heated in the mold. The rubber composition flows by pressurization and heating. The rubber composition causes a crosslinking reaction by heating, and the tire 2 shown in FIG. 1 is obtained.

  In this manufacturing method, the assembly sheet 74 obtained by cutting the assembly ribbon 56 is supplied to the former 76 and combined with other rubber members. This assembly sheet 74 is not stored in stock. This manufacturing method does not inhibit productivity.

  In this manufacturing method, an assembly sheet 74 in which the inner liner 20 and the side sheet 52 are joined in advance is used. In this manufacturing method, the number of rubber members combined in the former 76 is small. This manufacturing method can contribute to shortening the formation time of the raw cover. Productivity can be improved by using this manufacturing method.

  In this manufacturing method, it is preferable that the cutting edge is inclined with respect to the thickness direction of the assembly ribbon 56 and the cutter 70 cuts the assembly ribbon 56. The cut surface 80 of the assembly sheet 74 obtained by this cutting is inclined with respect to the thickness direction. As described above, the assembly sheet 74 supplied to the former 76 is wound around the drum 78 of the former 76, and the one cut surface 80a and the other cut surface 80b are joined. In the assembly sheet 74 having the inclined cut surface 80, a sufficiently large bonding area can be secured, so that the bonded state of the two cut surfaces 80 can be maintained well. Since the separation of the two cut surfaces 80 is prevented, the manufacturing method can stably manufacture the high-quality tire 2.

  6 is a cross-sectional view taken along line VI-VI in FIG. The vertical direction in FIG. 6 is the thickness direction of the assembly sheet 74. FIG. 6 shows a cross section of the upstream end portion of the assembly sheet 74 of FIG. As illustrated, the cut surface 80 of the assembly sheet 74 is inclined with respect to the thickness direction. In FIG. 6, the angle α represents an angle formed by the cut surface 80 with respect to the lower surface 90 of the assembly sheet 74. This angle α is the inclination angle of the cut surface 80. This inclination angle α is also referred to as a cut surface angle. From the viewpoint that the joining state of the two cut surfaces 80 is well maintained, the inclination angle α is preferably 15 ° or more, and more preferably 25 ° or less. As shown in FIG. 3, the VI-VI line is orthogonal to the cutting direction.

  In this manufacturing method, it is preferable that the cutter 70 is heated and used. By using such a cutter 70, irregularities in the cut surface 80 of the assembly sheet 74 can be suppressed. This suppression of irregularities can prevent air from being caught between the two cut surfaces 80. In this manufacturing method, it is possible to prevent appearance defects due to air remaining. In this manufacturing method, since molding defects of the tire 2 are suppressed, the high-quality tire 2 can be manufactured stably.

  In this manufacturing method, examples of the cutter 70 include a hot cutter and an ultrasonic cutter. From the viewpoint of cutting the assembly ribbon 56 without lowering the temperature and obtaining a cut surface 80 in which irregularities are suppressed, an ultrasonic cutter is preferably used as the cutter 70. Use of this ultrasonic cutter can contribute to stable production of the high-quality tire 2. This manufacturing method is excellent in productivity.

  As described above, in this manufacturing method, the guide roller 60 is configured to slide in the width direction. By this sliding, the position in the width direction of the side sheet 52 passed through the guide roller 60 can be controlled. In this manufacturing method, the side roller 52 can also be slid inward in the axial direction by sliding the guide roller 60 inward in the axial direction. By this slide, the tire 2 in which the position of the bead 8 shown in FIG. 5D is moved inward in the axial direction can be manufactured. In this manufacturing method, when the guide roller 60 is slid outward in the axial direction, the side seat 52 can also be slid outward in the axial direction. By this slide, the tire 2 in which the position of the bead 8 shown in FIG. 5D is moved outward in the axial direction can be manufactured. In this manufacturing method, it is easy to change the size of the tire 2 that can be manufactured. Since the manufacturing device 54 does not need to be stopped when changing the size of the tire 2 to be manufactured, this manufacturing method can contribute to an improvement in productivity.

  FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. In FIG. 7, the left-right direction is the width direction of the assembly sheet 74. FIG. 7 shows an overlapping portion 82 between the inner liner 20 and the side seat 52 positioned on the upper side in FIG. In FIG. 7, a double arrow line W represents the width of the overlapping portion 82. This width W is the bonding width. This joining width W is obtained by measuring the distance from the end 92 of the inner liner 20 to the end 94 of the side sheet 52. In this manufacturing method, sliding of the guide roller 60 inward in the axial direction can increase the joining width W. The sliding of the guide roller 60 outward in the axial direction can reduce the joining width W.

  In this manufacturing method, the bonding width W is preferably 15 mm or more and 35 mm or less. By setting the joining width W to 15 mm or more, productivity can be improved while maintaining good joining of the overlapping portion 82. In this respect, the bonding width W is more preferably 20 mm or more. By setting the joining width W to 35 mm or less, the influence on the tire quality of the overlapping portion 82 can be suppressed while maintaining good productivity. In this respect, the bonding width W is more preferably 30 mm or less.

  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]
100 tires having the basic configuration shown in FIG. 1 and the size of 11R22.5 were manufactured using a manufacturing apparatus having the basic configuration shown in FIGS. In Example 1, the position of the side sheet was adjusted using a guide roller (shown as A in Table 1). The side sheet and the inner liner were joined with a pressure roller. An ultrasonic cutter was used to cut the assembly ribbon. The assembly sheet was fed to the former by a conveyor and wound on a drum. The inclination angle α of the cut surface of the assembly sheet was 15 ° (degree). The joining width W between the inner liner and the side sheet was 15 mm.

[Example 7]
100 tires having the basic configuration shown in FIG. 1 and a size of 11R22.5 were manufactured in the same manner as in Example 1 except that the inclination angle of the cut surface was changed.

[Examples 2 to 6]
A guide roller is not provided (indicated as “B” in Table 1), and the inclination angle of the cut surface is changed, and the basic configuration shown in FIG. 100 tires were produced.

[Comparative Example 1]
Using a conventional manufacturing apparatus, 100 tires having the basic configuration shown in FIG. 1 and having a size of 11R22.5 were manufactured. In Comparative Example 1, the side sheet and the inner liner were each prepared separately and supplied to the former. In Comparative Example 1, an assembly ribbon (or assembly sheet) is not formed. The inclination angle of the cut surface of the side sheet was 45 °. The inclination angle of the cut surface of the inner liner was 30 °.

[Productivity evaluation]
The time required to produce one prototype tire was measured. Productivity was evaluated based on the reciprocal of this measurement time. The results are shown in Table 1 below as index values with Comparative Example 1 taken as 100. It is shown that productivity is excellent, so that this value is large.

[Appearance evaluation]
The appearance of the prototype tire was observed, and the number of tires in which an appearance defect due to residual air or the like was confirmed was measured. The ratio of this measured number to the total number of tires was calculated, and the defect occurrence rate was calculated. This defect occurrence rate is shown in Table 1 below as an index value with Comparative Example 1 taken as 100. Smaller numbers indicate better results.

  As shown in Table 1, the manufacturing method of the example is superior in productivity to the manufacturing method of the comparative example, and the defect occurrence rate is small. From this evaluation result, the superiority of the present invention is clear.

  The production method according to the present invention can be applied to the production of various tires.

FIG. 1 is a cross-sectional view showing a part of a heavy duty tire obtained by a manufacturing method according to an embodiment of the present invention. FIG. 2A is a plan view showing a part of the tire manufacturing apparatus of FIG. 1, and FIG. 2B is a front view thereof. FIG. 3 is a plan view showing another part of the tire manufacturing apparatus of FIG. 1. 4A is a plan view showing still another part of the tire manufacturing apparatus of FIG. 1, and FIG. 4B is a front view thereof. FIG. 5 is a partial cross-sectional view showing the formation state of the raw cover. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

Explanation of symbols

2 ... tyre 4 ... tread 6 ... side wall 8 ... bead 10 ... carcass 12 ... belt 14 ... reinforcing layer 16 ... cover rubber 18 ... inner side wall 20 ... Inner liner 22 ... Chafer 24 ... Tread surface 26 ... Groove 28 ... Core 30 ... Apex 32 ... Packing rubber 36 ... Carcass ply 38 ... First layer 40 ... Second layer 42 ... Third layer 44 ... Fourth layer 52 ... Side sheet 54 ... Manufacturing apparatus 56 ... Assembly ribbon 58 ... Pressure roller 60 ..Guide roller 62 ... first reel 64 ... second reel 70 ... cutter 72 ... conveyor 74 ... assembly sheet 76 ... former 78 ... drum 0,80a, 80b ··· cut surface

Claims (5)

A step of joining an edge portion of the inner liner and an edge portion of the side sheet to obtain an assembly ribbon;
Cutting the assembly ribbon to obtain an assembly sheet;
The assembly sheet is supplied to a former;
The assembly sheet is combined with other members to obtain a raw cover,
A method of manufacturing a heavy-duty tire including a step in which the raw cover is pressed and heated in a mold.   The manufacturing method according to claim 1, wherein in the step of obtaining the assembly sheet, the assembly ribbon is cut with an ultrasonic cutter.   The manufacturing method according to claim 1 or 2, wherein in the step of obtaining the assembly sheet, an inclination angle of a cut surface of the assembly sheet is 15 ° or more and 25 ° or less.   The manufacturing method according to any one of claims 1 to 3, wherein in the step of obtaining the assembly ribbon, a bonding width between the inner liner and the side sheet is 15 mm or more and 35 mm or less.   A pressure roller that can form an assembly ribbon by joining the inner liner and the side sheet, a cutter that can cut the assembly ribbon to form an assembly sheet, and other members are combined with the assembly sheet to form a raw cover. A heavy-duty tire manufacturing apparatus equipped with a former.

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