JP2017100393A - Method for production of pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire production method restraining occurrence of wrinkle and air residue while inhibiting the waving phenomenon of an insulation.SOLUTION: A tire production method comprises: an electron beam irradiation process of obtaining a semi-vulcanized sheet member; a semi-vulcanized sheet lamination process of obtaining a composite member 56 prepared by bonding the semi-vulcanized sheet member 40 to an insulation member 38; and a molding process of forming a raw cover by bonding the members composing the various parts of the tire including the composite member 56, a carcass member and an inner liner member. In the semi-vulcanized sheet lamination process, a semi-vulcanized sheet member 40 stretched by a tension Fe is bonded to the insulation member 38 stretched by a tension Fi. Besides, in the molding process, the above sheet member 40 positions between the carcass member and the insulation member 38.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a pneumatic tire.

  The method for manufacturing a pneumatic tire includes a molding step and a vulcanization step. In the molding step, members forming the respective parts of the tire are bonded together to obtain a raw cover (raw tire). In the vulcanization process, the raw cover is vulcanized and molded to obtain a tire.

  In the molding step, a carcass member that forms a carcass is laminated outside an inner liner member that forms an inner liner. An insulation member for forming an insulation is laminated between the inner liner member and the carcass member.

  In the vulcanization process, the raw cover is heated and pressurized. This heating and pressurization may cause the insulation member to be sucked up between the cords of the carcass member. In this specification, this phenomenon is called a wavy phenomenon. In this undulation phenomenon, the inner liner member is also sucked up between the cords of the carcass member together with the insulation member. This undulation phenomenon reduces the thickness of the tire installation and inner liner. The portion where the wavy phenomenon occurs tends to cause distortion concentration. This undulation phenomenon reduces the quality of the tire. It is conceivable to secure a sufficient thickness for the insulation and the inner liner by increasing the thicknesses of the insulation member and the inner liner member. However, increasing the thickness of the insulation member and the inner liner member causes poor adhesion in the molding process and poor molding in the vulcanization process.

  Japanese Unexamined Patent Application Publication Nos. 2012-183783 and 2015-116695 propose a method of irradiating a sheet-like rubber material with an electron beam. Japanese Patent Application Laid-Open No. 2012-183783 proposes that the surface of an insulation member is irradiated with an electron beam and partially vulcanized. By partially vulcanizing the insulation member in advance, the undulation phenomenon of the insulation member in the vulcanization process is suppressed.

  By using a semi-vulcanized insulation member by this electron beam irradiation method, the occurrence of the aforementioned undulation phenomenon can be suppressed. As a result, the occurrence of the undulation phenomenon is suppressed without increasing the thickness of the insulation member and the inner liner member.

JP 2012-183783 A JP2015-116695A

  When a long strip-shaped insulation member before cutting is irradiated with an electron beam to be in a semi-vulcanized state, the electron beam is irradiated to an unnecessary portion. In the insulation member irradiated with the electron beam, the surplus material cannot be reused.

  Moreover, when making the semi-vulcanized state by irradiating the cut installation member with an electron beam, it is necessary to irradiate the cut installation member with each electron beam. It takes time to irradiate each electron beam. Further, after the insulation member is bonded to another member, the electron beam is irradiated to the other member. Irradiation of the electron beam to other members is not preferable. For example, an inner liner member made of butyl rubber has limitations on electron beam irradiation. In addition, the belt member including the steel cord may be damaged in the adhesion between the steel cord and the rubber member due to the irradiation of the electron beam.

  For this reason, it can be considered that a semi-vulcanized rubber sheet irradiated with an electron beam is bonded to the insulation member. By using this semi-vulcanized rubber sheet, it is possible to prevent other members such as an insulation member, an inner liner member, and a belt member from being irradiated with an electron beam. By sticking a long strip-shaped semi-vulcanized rubber sheet to a long strip-shaped insulation member, there is no need to bond a semi-vulcanized rubber sheet for each of the cut insulation members.

  However, when a thick semi-vulcanized rubber sheet is bonded to the insulation member, the mass of the tire increases. On the other hand, when a thin semi-vulcanized rubber sheet is bonded to the insulation member, wrinkles are likely to occur in the long belt-like semi-vulcanized rubber sheet. Also, air residue is likely to occur between the insulation member and the semi-vulcanized rubber sheet.

  An object of the present invention is to provide a method for manufacturing a tire that suppresses generation of wrinkles and air remaining while suppressing the ripple phenomenon of insulation.

A method for manufacturing a pneumatic tire according to the present invention includes:
An electron beam irradiation step in which a semi-vulcanized sheet member obtained by irradiating an uncured rubber sheet member with an electron beam to vulcanize one surface in the thickness direction;
A semi-vulcanized sheet laminating step in which a composite member in which the semi-vulcanized sheet member is bonded to an insulation member forming an insulation is obtained;
A molding step in which a low cover is formed by bonding members constituting each part of the tire including the composite member, a carcass member forming a carcass, and an inner liner member forming an inner liner;
In the semi-vulcanized sheet laminating step, the semi-vulcanized sheet member stretched with tension Fe is bonded to the insulation member stretched with tension Fi. The tensile stress σe of this tension Fe is 0.1 MPa or more.
In the molding step, the semi-vulcanized sheet member is located between the carcass member and the insulation member.

  Preferably, in the semi-vulcanized sheet laminating step, the tensile stress σe of the tension Fe is 0.3 MPa or less.

  Preferably, in the semi-vulcanized sheet laminating step, the surface of the insulation member and the other back surface in the thickness direction of the semi-vulcanized sheet member are bonded together.

  Preferably, in the molding step, the semi-vulcanized sheet member is disposed in a buttress portion of a tire obtained from the raw cover. Arranged in this manner, the composite member and the carcass member are laminated.

  Preferably, in the molding step, a cushion layer member for forming a cushion layer is laminated outside the carcass member. The axially inner end of the semi-vulcanized sheet member is positioned axially inward from the axially inner end of the cushion layer member, and the axially outer end of the semi-vulcanized sheet member is the axis of the cushion layer member. It is located in the axial direction outside from the direction outer end. Positioned in this manner, the composite member, the carcass member, and the cushion layer member are laminated.

  Preferably, the distance from the inner end in the axial direction of the semi-vulcanized sheet member to the inner end in the axial direction of the cushion layer member is not less than 5 mm and not more than 10 mm. The distance from the axially outer end of the semi-vulcanized sheet member to the axially outer end of the cushion layer member is 5 mm or more and 10 mm or less.

  Preferably, the thickness of the semi-vulcanized sheet member is 0.4 mm or more and 0.8 mm or less.

  Preferably, the rubber composition of the semi-vulcanized sheet member is composed of the rubber composition of the insulation member.

  Preferably, in the semi-vulcanized sheet laminating step, the absolute value of the difference between the tensile stress σe of the tension Fe and the tensile stress σi of the tension Fi is 0.3 MPa or less.

The pneumatic tire according to the present invention includes a tread, a pair of sidewalls, a pair of beads, a carcass, an inner liner, an insulation, and a pair of rubber sheets.
The tread includes a tread surface that contacts the road surface. Each sidewall extends substantially inward in the radial direction from the end of the tread. Each bead is located on the axially inner side of the sidewall. The carcass includes a carcass ply. This carcass ply is composed of a number of cords and a topping rubber. The carcass ply is stretched between one bead and the other bead along the inside of the tread and the sidewall. The inner liner is located inside the carcass. The insulation is laminated between the inner liner and the carcass. The rubber sheet is laminated between the insulation and the carcass. The rubber sheet is disposed in a buttress portion from the shoulder of the tread to the sidewall. Along the axial end of the rubber sheet, a boundary is formed in which the amount by which the insulation is sucked between the cords of the carcass ply is different.

  Preferably, the tire includes a belt and a pair of cushion layers. The belt is laminated with the carcass on the inner side in the radial direction of the tread. The cushion layer is laminated between the axial end of the belt and the carcass. The inner end in the axial direction of the rubber sheet is located on the inner side in the axial direction from the inner end in the axial direction of the cushion layer. The outer end in the axial direction of the rubber sheet is located on the outer side in the axial direction from the outer end in the axial direction of the cushion layer.

  Preferably, the thickness of the rubber sheet of this tire is not less than 0.4 mm and not more than 0.8 mm.

  In the manufacturing method according to the present invention, semi-vulcanized sheet members are laminated. By providing this semi-vulcanized sheet member, it is suppressed that the insulation is sucked up between the carcass cords in the vulcanization process. In this molding process, since the semi-vulcanized sheet member irradiated with the electron beam in advance is laminated, the insulation member and other members are not vulcanized by the irradiation of the electron beam. The insulation member is stretched in the longitudinal direction by the tension Fi. The semi-vulcanized sheet member is stretched in the longitudinal direction with the tension Fe. Since this insulation member and the semi-vulcanized sheet member are bonded together, generation of soot and air residue is suppressed.

FIG. 1 is a cross-sectional view of a pneumatic tire manufactured by a manufacturing method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is an explanatory diagram of a manufacturing method according to an embodiment of the present invention. FIG. 4 is another explanatory view of the manufacturing method according to the embodiment of the present invention.

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

  FIG. 1 shows a pneumatic tire 2. In FIG. 1, the vertical direction is the radial direction of the tire 2, the horizontal direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2. In FIG. 1, an alternate long and short dash line CL represents the equator plane of the tire 2. A straight line BL represents a bead base line. The bead base line is a line that defines the rim diameter of the normal rim. The shape of the tire 2 is symmetrical with respect to the equator plane except for the tread pattern.

  The tire 2 includes a tread 4, a pair of sidewalls 6, a pair of clinch 8, a pair of beads 10, a carcass 12, a belt 14, an inner liner 16, a pair of cushion layers 18, a pair of chafers 20, an insulation 22 and A pair of rubber sheets 24 is provided. The tire 2 is a heavy load tire. The tire 2 is mounted on, for example, a truck or a bus.

  The tread 4 forms a tread surface 26 that contacts the road surface. The tread 4 has a groove. A tread pattern is formed by this groove. Although not shown, the tread 4 has a base layer and a cap layer. The cap layer is located on the radially outer side of the base layer. The cap layer is laminated on the base layer. The base layer is made of a crosslinked rubber having excellent adhesiveness. A typical base rubber for the base layer is natural rubber. The cap layer is made of a crosslinked rubber having excellent wear resistance, heat resistance and grip properties.

  Each sidewall 6 extends substantially inward in the radial direction from the end of the tread 4. A radially outer end of the sidewall 6 is joined to the tread 4. The radially inner end of the sidewall 6 is joined to the clinch 8. This sidewall 6 is made of a crosslinked rubber having excellent cut resistance and weather resistance. This sidewall 6 prevents the carcass from being damaged. Each clinch 8 is located substantially inside the sidewall 6 in the radial direction. The clinch 8 is made of a crosslinked rubber having excellent wear resistance. The clinch 8 contacts the flange 28f of the rim 28.

  Each bead 10 is located inside the clinch 8 in the axial direction. The bead 10 includes a core 30, a first apex 32, and a second apex 34. The core 30 has a ring shape and includes a wound non-stretchable wire. A typical material for the wire is steel. The first apex 32 extends radially outward from the core 30. The first apex 32 is made of a highly hard crosslinked rubber. The second apex 34 is located on the outer side in the axial direction and on the outer side in the radial direction than the first apex 32. The second apex 34 is softer than the first apex 32.

  The carcass 12 includes a carcass ply 36. The carcass ply 36 is bridged between the beads 10 on both sides, and extends along the tread 4 and the sidewall 6. The carcass ply 36 is folded around the core 30 from the inner side to the outer side in the axial direction. By this folding, the carcass ply 36 is formed with a main portion 36a and a folding portion 36b. The carcass ply 36 includes a large number 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 75 ° to 90 °. In other words, the carcass 12 has a radial structure. The cord material is steel. The carcass 12 may be formed from two or more carcass plies 36.

  The belt 14 is located on the inner side in the radial direction of the tread 4. The belt 14 is laminated with the carcass 12. The belt 14 reinforces the carcass 12. The belt 14 includes a first layer 14a, a second layer 14b, a third layer 14c, and a fourth layer 14d. As is apparent from the figure, among the four layers, the second layer 14b has the largest axial width. In the tire 2, the axial width of the second layer 14 b is the axial width of the belt 14.

  Although not shown, each of the first layer 14a, the second layer 14b, the third layer 14c, and the fourth layer 14d 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 inclination direction of the cord of the first layer 14a with respect to the equator plane is the same as the inclination direction of the cord of the second layer 14b with respect to the equator plane. The direction of inclination of the cord of the second layer 14b with respect to the equator plane is opposite to the direction of inclination of the cord of the third layer 14c with respect to the equator plane. The inclination direction of the cord of the third layer 14c with respect to the equator plane is the same as the inclination direction of the cord of the fourth layer 14d with respect to the equator plane. In each layer, the absolute value of the angle formed by the cord with respect to the equator plane is 15 ° to 70 °. In this belt 14, the cords of the first layer 14a and the second layer 14b and the cords of the third layer 14c and the fourth layer 14d extend so as to intersect each other. The belt 14 is not limited to four layers. The belt 14 is preferably composed of two or more layers in which the cords cross each other.

  The inner liner 16 is located inside the carcass 12. The inner liner 16 is joined to the inner surface of the carcass 12. The inner liner 16 is made of a crosslinked rubber having excellent air shielding properties. A typical base rubber of the inner liner 16 is butyl rubber or halogenated butyl rubber. The inner liner 16 holds the internal pressure of the tire 2. The tire 2 is a tubeless tire. The tire 2 may be a tube type including a tube. The internal pressure of the tube type tire 2 is adjusted by filling the tube with air. The tube type tire 2 also includes a rubber layer corresponding to the inner liner 16 and the insulation 22 on the inner surface of the carcass 12.

  Each cushion layer 18 is laminated with the carcass 12 in the vicinity of the end of the belt 14. The cushion layer 18 is made of a soft crosslinked rubber. The cushion layer 18 absorbs stress at the end of the belt 14. The cushion layer 18 suppresses lifting of the belt 14.

  Each chafer 20 is located in the vicinity of the bead 10. When the tire 2 is incorporated into the rim 28, the chafer 20 contacts the rim 28. By this contact, the vicinity of the bead 10 is protected. In the tire 2, the chafer 20 is integral with the clinch 8. Therefore, the material of the chafer 20 is the same as that of the clinch 8.

  The insulation 22 is located inside the sidewall 6 in the axial direction. The insulation 22 is sandwiched between the carcass 12 and the inner liner 16. The insulation 22 is made of a crosslinked rubber having excellent adhesiveness. The insulation 22 is firmly joined to the carcass 12 and is also firmly joined to the inner liner 16. The insulation 22 suppresses the peeling between the inner liner 16 and the carcass 12.

  Each rubber sheet 24 is located between the carcass 12 and the insulation 22. As shown in FIG. 1, the rubber sheet 24 is disposed in a region from the shoulder of the tread 4 to the sidewall 6. In other words, the rubber sheet 24 is disposed in the buttress portion of the tire 2.

  Reference numeral 18 a in FIG. 1 represents an inner end in the axial direction of the cushion layer 18. Reference numeral 18 b represents an outer end in the axial direction of the cushion layer 18. Reference numeral 24 a represents an inner end in the axial direction of the rubber sheet 24. Reference numeral 24 b represents an outer end in the axial direction of the rubber sheet 24. The inner end 24 a of the rubber sheet 24 is located on the inner side in the axial direction from the inner end 18 a of the cushion layer 18. The outer end 24 b of the rubber sheet 24 is located on the outer side in the axial direction from the outer end 18 b of the cushion layer 18. In the tire 2, the inner end 18 a of the cushion layer 18 is also a joint outer end of the carcass 12 and the belt 14 in the axial direction. In other words, the inner end 24 a of the rubber sheet 24 is located on the inner side in the axial direction from the outer end where the carcass 12 and the belt 14 are joined.

  A double arrow La in FIG. 1 represents a distance from the inner end 18a of the cushion layer 18 to the inner end 24a of the rubber sheet 24. A double-headed arrow Lb represents the distance from the outer end 18b of the cushion layer 18 to the outer end 24b of the rubber sheet 24. The distance La and the distance Lb are measured along the boundary between the rubber sheet 24 and the carcass 12 in the cross section of FIG.

  As shown in FIG. 2, the insulation 22 is laminated outside the inner liner 16 in the buttress portion. A rubber sheet 24 is laminated outside the insulation 22. The carcass 12 is laminated on the outside of the rubber sheet 24. In FIG. 2, a cord 36a and a topping rubber 36b of the carcass ply 36 are shown. A double arrow t in FIG. 2 represents the thickness of the rubber sheet 24.

  The manufacturing method of the tire 2 includes an electron beam irradiation process, a semi-vulcanized sheet laminating process, a forming process, and a vulcanizing process.

  FIG. 3 is an explanatory diagram of the semi-vulcanized sheet lamination step. FIG. 3 shows a part of the crimping device 42 together with the insulation member 38 and the rubber sheet member 40. In the tire 2, the insulation 22 is formed from the installation member 38. A rubber sheet 24 is formed from the rubber sheet member 40. The rubber sheet member 40 is a semi-vulcanized sheet member obtained in an electron beam irradiation process described later. The crimping device 42 includes a tension roller 44, a first roller 46, a second roller 48, a third roller 50, and a fourth roller 52.

  An arrow A in FIG. 3 represents a direction in which the insulation member 38 and the rubber sheet member 40 are sent. The rubber sheet member 40 obtained in the electron beam irradiation process is sent to the semi-vulcanized sheet laminating process in a state of being scraped off by the roll 54. When the rubber sheet member 40 is unwound from the roll 54, a resistance force R opposite to the rotation direction is applied to the roll 54. An arrow Ft represents the pressing force that the rubber sheet member 40 receives by the tension roller 44.

  The rubber sheet member 40 has a thin strip shape. The width of the rubber sheet member 40 is, for example, 100 mm or more and 200 mm or less. The thickness of the rubber sheet member 40 is, for example, 0.6 mm. The insulation member 38 has a strip shape. The width of the insulation member 38 is much larger than that of the rubber sheet member 40. The thickness of the insulation member 38 is larger than the thickness of the rubber sheet member 40.

  The rubber sheet member 40 fed out from the roll 54 is guided and sent to the tension roller 44, the first roller 46, the second roller 48, the third roller 50, and the fourth roller 52. The surface 40 a of the rubber sheet member 40 is covered with a protective sheet 62. The insulation member 38 is guided and sent to the third roller 50 and the fourth roller 52. The tension is also applied to the insulation member 38 in the longitudinal direction.

  The insulation member 38 is guided by the third roller 50 and sent. The second roller 48 and the fourth roller 52 press the rubber sheet member 40 against the insulation member 38 guided by the third roller 50. The rubber sheet member 40 is pressed against the insulation member 38 between the second roller 48 and the fourth roller 52. The rubber sheet member 40 that is tensioned and stretched in the longitudinal direction is pressed against the installation member 38 that is tensioned and stretched in the longitudinal direction. The back surface 40b of the rubber sheet member 40 is pressure-bonded to the front surface 38a of the insulation member 38. A composite member 56 in which the insulation member and the rubber sheet member 40 are pressure-bonded is formed.

  FIG. 4 is another explanatory view of the semi-vulcanized sheet laminating step. In FIG. 4, the guide plate 58 and the guide roller 60 are shown together with the composite member 56. The crimping device 42 includes a guide 58 and a guide roller 60. The surface 40 a of the rubber sheet member 40 is covered with a protective sheet 62. This protective sheet 62 is fed to the guide plate 58 through the fourth roller 52 of FIG. The protective sheet 62 is guided by the guide plate 58 and peeled off from the surface 40 a of the rubber sheet member 40. The peeled protective sheet 62 is guided by the guide roller 60 and sent.

  An arrow A1 in FIG. 4 represents the direction in which the composite member 56 is sent. Arrow A2 represents the direction in which the protective sheet 62 is sent. An alternate long and short dash line Lc represents a direction in which the protective sheet 62 is peeled off. A double arrow θ represents the peeling angle of the protective sheet 62. This peeling angle θ is an angle formed between the surface 40a of the rubber sheet member 40 and the direction Lc in which the protective sheet 62 is peeled off.

  Below, the manufacturing method of this tire 2 is demonstrated, referring this FIG.3 and FIG.4.

  Although not shown, in the electron beam irradiation step, the electron beam irradiation device irradiates the surface 40a of the unvulcanized rubber sheet member 40 with an electron beam. The rubber sheet member 40 is irradiated with an electron beam set to a predetermined irradiation voltage and irradiation dose. The surface 40a of the rubber sheet member 40 is vulcanized by the predetermined irradiation voltage and irradiation dose. With this predetermined irradiation voltage and irradiation dose, the back surface 40b of the rubber sheet member 40 is not vulcanized. The hardness of the front surface 40a after being irradiated with the electron beam is higher than the hardness of the back surface 40b. The rubber sheet member 40 is in a semi-vulcanized state. As the electron beam irradiation apparatus, for example, a scanning electron beam irradiation apparatus or an area type electron beam irradiation apparatus is used.

  The surface 40 a of the rubber sheet member 40 that has been semi-vulcanized is covered with a protective sheet 62. The rubber sheet member 40 is scraped off by the roll 54 together with the protective sheet 62. This roll 54 is sent to the semi-vulcanized sheet laminating step.

  As shown in FIG. 3, in the semi-vulcanized sheet laminating step, a roll 54 is installed in the crimping device 42. The rubber sheet member 40 is fed out from the roll 54. The rubber sheet member 40 is guided and sent to the tension roller 44, the first roller 46, the second roller 48, the third roller 50, and the fourth roller 52 together with the protective sheet 62. The roll 54 imparts a resistance force R that is opposite to the feeding direction in the rotation direction. The tension roller 44 presses the rubber sheet member 40 with a pressing force Ft between the roll 54 and the first roller 46. The tension roller 40 applies tension to the rubber sheet member 40.

  The tension roller 44 can adjust the magnitude of the pressing force Ft. For example, the tension roller 44 adjusts the pressing force Ft in three stages. The tension roller 44 can adjust the tension in the longitudinal direction of the rubber sheet member 40.

  The rubber sheet member 40 and the insulation member 38 are fed while being guided by the third roller 50 and the fourth roller 52. The rubber sheet member 40 is bonded to the installation member 38 between the second roller 48 and the fourth roller 52. The back surface 40 b of the rubber sheet member 40 is bonded to the front surface 38 a of the insulation member 38.

  Although not shown, a pair of rubber sheet members 40 are bonded to the insulation member 38. The pair of rubber sheet members 40 are bonded to each other at a predetermined interval in the width direction of the insulation member 38. A pair of rubber sheet members 40 and the insulation member 38 are bonded together to form a composite member 56.

  Each rubber sheet member 40 is applied with tension Fe and bonded to the insulation member 38. This tension Fe is greater than zero. The insulation member 38 is provided with a tension Fi and is bonded to a pair of rubber sheet members. This tension Fi is greater than zero. This tension Fe is measured by the rubber sheet member 40 stretched between the third roller 50 and the second roller 48. This tension Fi is measured by an insulation member 38 stretched between the third roller 50 and a roller (not shown) upstream in the feed direction of the third roller 50 (on the opposite side to the fourth roller 54 in the feed direction).

  Each rubber sheet member 40 has a tensile stress σe due to the tension Fe. The tensile stress σe is obtained by dividing the tension Fe by a cross section perpendicular to the longitudinal direction of the rubber sheet member 40. A tensile stress σi is generated in the insulation member 38 due to the tension Fi. The tensile stress σi is obtained by dividing the tension Fi by a cross section perpendicular to the longitudinal direction of the installation member 38.

  As shown in FIG. 4, the composite member 56 is fed toward the guide plate 58. The protective sheet 62 is supported by the guide plate 58, and the protective sheet 62 is peeled off from the rubber sheet member 40. The protective sheet 62 is peeled off from the surface 40a at a peeling angle θ. The peeled protective sheet 62 is guided by the guide roller 60 and sent in the direction of the arrow A2. Although not shown, the protective sheet 62 is scraped off and reused. The composite member 56 from which the protective sheet 62 has been peeled is sent in the direction of the arrow A1.

  In the molding process, including the composite member 56, a tread member that forms the tread 4, a sidewall member that forms the sidewall 6, a carcass member that forms the carcass 12, an inner liner member that forms the inner liner 16, and a cushion layer Members for forming each part of the tire 2 such as a cushion layer member for forming the tire 18 are prepared. These members are sequentially bonded to form a raw cover.

  In this molding step, the composite member 56 is laminated between the inner liner member and the carcass member. The surface 40a of the rubber sheet member 40 is bonded to the carcass member. In the rubber sheet member 40, the composite member and the carcass member are bonded together so as to be disposed at the position of the buttress portion of the tire 2. The cushion layer member is bonded to the outside of the carcass member. The cushion layer member is disposed at the position of the buttress portion of the tire 2. At the position of the buttress portion of the tire 2, the rubber sheet member 40 and the cushion layer member are laminated with a carcass member therebetween. In this raw cover, the inner end in the axial direction of the rubber sheet member 40 is located on the inner side in the axial direction from the inner end in the axial direction of the cushion layer member. The outer end in the axial direction of the rubber sheet member 40 is located on the outer side in the axial direction from the outer end in the axial direction of the cushion layer member.

  In the vulcanization process, this raw cover is put into a mold. The raw cover is heated at a predetermined temperature and pressurized at a predetermined pressure. This raw cover is vulcanized in a mold. By this vulcanization molding, the tire 2 is obtained from the raw cover.

  In the tire 2 manufacturing method, the rubber sheet member 40 is semi-vulcanized in the electron beam irradiation step. In the semi-vulcanized sheet stacking step, the semi-vulcanized rubber sheet member 40 is bonded to the installation member 38. In this method, other members other than the rubber sheet member 40 are not irradiated with the electron beam. In this method, other members than the rubber sheet member 40 are not vulcanized before the vulcanization step.

  In the semi-vulcanized sheet laminating step, a rubber sheet member 40 stretched with tension Fe is bonded to an insulation member 38 stretched with tension Fi. As a result, the occurrence of air residue between the insulation member 38 and the rubber sheet member 40 is suppressed. Generation | occurrence | production of a wrinkle is suppressed by the bonded insulation member 38 and the rubber sheet member 40. FIG. According to this method, even if the rubber sheet member 40 is thinned, wrinkles and air residue are unlikely to occur.

  From the viewpoint of suppressing generation of wrinkles and air remaining using the thin rubber sheet member 40, the tensile stress σe of the rubber sheet member 40 is 0.1 MPa or more. On the other hand, even if the tensile stress σe is too large in the thin rubber sheet member 40, wrinkles and air remaining are generated. From this viewpoint, the tensile stress σe is preferably 0.3 MPa or less.

  The back surface 40b of the rubber sheet member 40 is a surface opposite to the surface 40a irradiated with the electron beam. In the electron beam irradiation process, the back surface 40b is suppressed from being vulcanized. In the semi-vulcanized sheet stacking step, the back surface 40b is bonded to the surface 38a of the insulation member 38. Thereby, even if the rubber sheet member 40 is semi-vulcanized, the adhesiveness between the rubber sheet member 40 and the insulation member 38 is not impaired. In this method, since the unvulcanized surface 40a is bonded to the insulation member 38 made of unvulcanized rubber, the adhesiveness is excellent.

  From the viewpoint of adhesiveness between the rubber sheet member 40 and the insulation member 38, the rubber sheet member 40 is preferably made of the same rubber composition as the insulation member 38.

  Since the rubber sheet member 40 is semi-vulcanized in advance, even in the vulcanization process, the occurrence of undulation phenomenon in which the rubber sheet member 40 is sucked up between the cords of the carcass member is suppressed. Occurrence of the undulation phenomenon in which the insulation member 38 is sucked up is suppressed.

  In the vulcanization process, the raw cover is expanded radially outward. Due to this diameter expansion, the raw cover is more easily stretched at the outer portion than at the radially inner portion. For this reason, the undulation phenomenon is more likely to occur in the outer portion than in the radially inner portion of the raw cover. In the tire 2, a belt member is laminated on a carcass member. In the portion where the belt member is laminated, the belt member suppresses the occurrence of the wavy phenomenon. In the tire 2, this undulation phenomenon is likely to occur particularly in the buttress portion. In the tire 2, since the rubber sheet member 40 is disposed in the buttress portion, this undulation phenomenon is effectively suppressed. This rubber sheet member 40 minimizes its width, and this undulation phenomenon is effectively suppressed.

  The carcass 12 of the tire 2 has a radial structure. The tire 2 is a so-called radial tire. The cord of the carcass ply 36 extends in the axial direction. In the raw cover of the tire 2, when the diameter is expanded in the vulcanization process, the distance between the cords extending in the axial direction becomes wider on the outer side in the radial direction. In the tire 2 including the carcass 12, the undulation phenomenon is likely to occur. Since the tire 2 includes the rubber sheet member 40, the wavy phenomenon is suppressed. This manufacturing method is suitable for a radial tire manufacturing method.

  The tire 2 includes a cushion layer 18. The cushion layer 18 absorbs stress at the end of the belt 14. The cushion layer 18 is made of a soft crosslinked rubber. The tire 2 including the cushion layer 18 is suitable for a heavy load tire. On the other hand, the cushion layer 18 is located in the buttress portion of the tire 2. The cushion layer 18 is easy to promote the undulation phenomenon. In the tire 2, a rubber sheet member 40 is laminated inside a carcass member in which cushion layer members are laminated. Thereby, even if it has the cushion layer 18, a wavy phenomenon is suppressed effectively. This manufacturing method is suitable for a method for manufacturing a heavy duty tire.

  In the molding step, in the raw cover of the tire 2, the inner end in the axial direction of the rubber sheet member 40 is located on the inner side in the axial direction from the inner end in the axial direction of the cushion layer member. The outer end in the axial direction of the rubber sheet member 40 is located on the outer side in the axial direction from the outer end in the axial direction of the cushion layer member. In this way, the composite member 56, the carcass member, and the cushion layer member are laminated. In this method, the undulation phenomenon at the buttress portion is effectively suppressed.

  By increasing the distance from the inner end in the axial direction of the rubber sheet member 40 to the inner end in the axial direction of the cushion layer member, the undulation phenomenon can be more reliably suppressed. From this viewpoint, this distance is preferably 5 mm or more. On the other hand, shortening this distance contributes to weight reduction of the tire 2. From this viewpoint, this distance is preferably 10 mm or less. Similarly, the distance from the axial outer end of the rubber sheet member 40 to the axial outer end of the cushion layer member is preferably 5 mm or more. This distance is preferably 10 mm or less.

  In this semi-vulcanized sheet laminating step, a rubber sheet member 40 stretched with tension Fe is bonded to an insulation member 38 stretched with tension Fi. Thereby, even if it uses the rubber sheet member 40 thinner than before, generation | occurrence | production of a soot and air remainder is suppressed. This thin rubber sheet member 40 contributes to weight reduction of the tire 2. From this viewpoint, the thickness is preferably 0.8 mm or less, and more preferably 0.7 mm or less. On the other hand, from the viewpoint of suppressing generation of soot and air remaining, this thickness is preferably 0.4 mm or more, and more preferably 0.5 mm or more.

  If the difference between the tensile stress σi of the insulation member 38 and the tensile stress σe of the rubber sheet member 40 is large, soot and air remaining are likely to occur in the composite member 56. From this viewpoint, the absolute value of the difference between the tensile stress σe and the tensile stress σi is preferably 0.3 MPa or less.

  In the semi-vulcanized sheet stacking step, the protective sheet 62 is supported by the guide plate 58 and the protective sheet 62 is peeled off from the rubber sheet member 40. As a result, the rubber sheet member 40 is prevented from being peeled off from the insulation member 38. Generation of wrinkles and air residue between the rubber sheet member 40 and the insulation member 38 is suppressed. From this viewpoint, the peeling angle θ is preferably greater than 90 °, and more preferably 100 ° or more. When the peeling angle θ is too large, the protective sheet 62 is difficult to peel from the rubber sheet member 40. From this viewpoint, the peeling angle θ is preferably 150 ° or less, and more preferably 140 ° or less.

  In the tire 2 manufactured by this manufacturing method, the rubber sheet 24 is laminated between the insulation 16 and the carcass 12. The rubber sheet 24 is disposed in the buttress portion from the shoulder of the tread 4 to the sidewall 6. In the tire 2, the occurrence of the undulation phenomenon is effectively suppressed. In the tire 2, the undulation phenomenon is suppressed in a range where the rubber sheet 24 is located. The amount by which the insulation 16 is sucked up between the cords 36a of the carcass ply 36 in the inner surface of the carcass 12 in the cross section of the tire 2 in FIG. Are very different. In the tire 2, a boundary is formed along the axial end of the rubber sheet 24 where the amount of suction of the insulation 16 is different.

  In the tire 2, the rubber sheet 24 is located inside the carcass 12 on which the action layer 18 is laminated. Thereby, even if the cushion layer 18 is provided, the undulation phenomenon is effectively suppressed. From this viewpoint, it is preferable that the inner end 24 a of the rubber sheet 24 is positioned on the inner side in the axial direction from the inner end 18 a of the cushion layer 18. The outer end 24b of the rubber sheet 24 is preferably located on the outer side in the axial direction from the outer end 18b of the cushion layer 18. The distance La between the inner end 24a and the inner end 18a is preferably 5 mm or more. The distance Lb between the outer end 24b and the outer end 18b is preferably 5 mm or more. On the other hand, from the viewpoint of weight reduction, the distance La is preferably 10 mm or less. The distance Lb is preferably 10 mm or less.

  In the tire 2 manufactured by this manufacturing method, the thickness of the rubber sheet 24 can be made thinner than before. The thin rubber sheet 24 contributes to the weight reduction of the tire 2. From this viewpoint, the thickness t of the rubber sheet 24 is preferably 0.8 mm or less, and more preferably 0.7 mm or less. On the other hand, from the viewpoint of suppressing generation of soot and air remaining around the rubber sheet, the thickness t is preferably 0.4 mm or more, and more preferably 0.5 mm or more.

  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]
The tire of FIG. 1 was manufactured by the manufacturing method according to the present invention. This tire is a heavy duty pneumatic tire. The tire size was 315 / 80R22.5. The column of “Rubber Sheet” in Table 1 indicates the presence or absence of a rubber sheet that is a semi-vulcanized sheet. “Σe” represents the tensile stress of the rubber sheet member in the semi-vulcanized sheet lamination step. “Σi” represents the tensile stress of the insulation member in the semi-vulcanized sheet lamination step.

[Conventional example]
Commercial tires were prepared. This tire had the same configuration as the tire of Example 1 except that the rubber sheet was not provided.

[Example 2-3 and comparative example]
A tire similar to that in Example 1 was manufactured in the same manner as in Example 1 except that the tensile stresses σe and σi in the semi-vulcanized sheet lamination step were changed.

[Evaluation of firewood, air remaining and so on]
100 low covers for each tire were produced. The manufactured raw cover was disassembled, and the presence or absence of wrinkles around the rubber sheet member and the presence or absence of air remaining were evaluated. The evaluation results are shown in Table 1 below. This evaluation is evaluated in three stages. The larger the value, the better.

[Low cover defect rate]
The defective rate of the 100 low covers produced was evaluated. The defect rates were all at a level having no practical problem, but a relative evaluation was made for comparative evaluation. The result is shown as an index with the conventional example being 100. As this index is smaller, the defect rate is lower. The smaller this value is, the more preferable this evaluation result is.

[Defect rate of tires]
One hundred tires were produced. The defective rate of this tire was evaluated. The defect rates were all at a level having no practical problem, but a relative evaluation was made for comparative evaluation. The result is shown as an index with the conventional example being 100. As this index is smaller, the defect rate is lower. The smaller this value is, the more preferable this evaluation result is.

[Evaluation of wavy phenomenon]
The tire was disassembled, and the presence or absence of the undulation phenomenon at the buttress portion was evaluated. All tires were at a level where there was no problem in practical use, but a relative evaluation was made. The evaluation results are shown in Table 1 below. This evaluation is evaluated in three stages. The larger the value, the better.

  As shown in Table 1, the manufacturing method of the example has a 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 widely applied to the manufacture of pneumatic tires. This manufacturing method is particularly suitable for manufacturing a radial tire and a tire including a cushion layer.

2 ... tyre 4 ... tread 6 ... side wall 12 ... carcass 14 ... belt 16 ... inner liner 18 ... cushion layer 22 ... insulation 24 ... rubber sheet 36 ... Carcass ply 38 ... Insulation member 40 ... Rubber sheet member 42 ... Crimping device 44 ... Tension roller 46 ... First roller 48 ... Second roller 50 ... Third roller 52 ... Fourth roller 56 ... Composite member 58 ... Guide plate 60 ... Guide roller 62 ... Protective sheet

Claims (12)

An electron beam irradiation step in which a semi-vulcanized sheet member obtained by irradiating an uncured rubber sheet member with an electron beam to vulcanize one surface in the thickness direction;
A semi-vulcanized sheet laminating step in which a composite member in which the semi-vulcanized sheet member is bonded to an insulation member forming an insulation is obtained;
A molding step in which a low cover is formed by bonding members constituting each part of the tire, including the composite member, a carcass member that forms a carcass, and an inner liner member that forms an inner liner;
In the semi-vulcanized sheet laminating step, the semi-vulcanized sheet member stretched with tension Fe is bonded to the insulation member stretched with tension Fi, and the tensile stress σe of the tension Fe is 0.1 MPa. That's it,
The method for producing a pneumatic tire, wherein the semi-vulcanized sheet member is located between the carcass member and the insulation member in the molding step.   The manufacturing method according to claim 1, wherein in the semi-vulcanized sheet laminating step, the tensile stress σe of the tension Fe is 0.3 MPa or less.   The manufacturing method of Claim 1 or 2 with which the surface of the said insulation member and the other back surface of the thickness direction of the said semi-vulcanized sheet member are bonded together in the said semi-vulcanized sheet lamination process.   In the said formation process, the said semi-vulcanized sheet member is arrange | positioned at the buttress part of the tire obtained from the said raw cover, The said composite member and the said carcass member are laminated | stacked. Production method. In the molding step, a cushion layer member that forms a cushion layer on the outside of the carcass member is laminated,
The axially inner end of the semi-vulcanized sheet member is positioned axially inward from the axially inner end of the cushion layer member, and the axially outer end of the semi-vulcanized sheet member is the axial direction of the cushion layer member. The manufacturing method according to claim 4, wherein the composite member, the carcass member, and the cushion layer member are laminated so as to be positioned on the outer side in the axial direction from the outer end.   The distance from the axially inner end of the semi-vulcanized sheet member to the axially inner end of the cushion layer member is 5 mm or more and 10 mm or less, and the axially outer end of the cushion layer member from the axially outer end of the semi-vulcanized sheet member The manufacturing method according to claim 5, wherein the distance to the end is 5 mm or more and 10 mm or less.   The manufacturing method according to any one of claims 1 to 6, wherein the semi-vulcanized sheet member has a thickness of 0.4 mm or more and 0.8 mm or less.   The manufacturing method according to claim 1, wherein the rubber composition of the semi-vulcanized sheet member is made of the rubber composition of the insulation member.   9. The production according to claim 1, wherein, in the semi-vulcanized sheet laminating step, an absolute value of a difference between a tensile stress σe of the tension Fe and a tensile stress σi of the tension Fi is 0.3 MPa or less. Method. It has a tread, a pair of sidewalls, a pair of beads, a carcass, an inner liner, an installation and a pair of rubber sheets.
The tread has a tread surface that contacts the road surface,
Each sidewall extends radially inward from the end of the tread,
Each bead is located axially inside the sidewall,
The carcass includes a carcass ply, and the carcass ply is composed of a number of cords and a topping rubber.
The carcass ply is bridged between one bead and the other bead along the inside of the tread and the sidewall,
The inner liner is located inside the carcass, and the insulation is laminated between the inner liner and the carcass,
The rubber sheet is laminated between the insulation and the carcass,
The rubber sheet is arranged in the buttress part from the shoulder of the tread to the sidewall,
A pneumatic tire in which a boundary is formed along the axial end of the rubber sheet so that the amount by which the insulation is sucked between the cords of the carcass ply is different. A belt and a pair of cushion layers,
The belt is laminated with the carcass radially inside the tread;
The cushion layer is laminated between the axial end of the belt and the carcass;
The axial inner end of the rubber sheet is positioned axially inward from the axial inner end of the cushion layer, and the axial outer end of the rubber sheet is positioned axially outer than the axial outer end of the cushion layer. The tire according to claim 10.   The tire according to claim 10 or 11, wherein the rubber sheet has a thickness of 0.4 mm or more and 0.8 mm or less.

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