JP2016084028A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire 34 maintaining a good external appearance even when stored in a stacked flat state.SOLUTION: A tire 34 includes a tread 44, a pair of side walls 46, a pair of clinches 48, a pair of beads 50, a carcass 52 and a pair of fillers 60. Either side wall 46 comprises a main body 70 and a colored body 72 embedded in the main body 70 and comprising a mark 38. Either filler 60 extends radially between the carcass 52 and the side wall 46/the clinch 48. An inner end 98 of the filler 60 is positioned on a radial inner side with respect to an outer end 100 of an apex 80 of the bead 50. The ratio of a radial height between a bead baseline and an outer end 102 of the filler 60 to a radial height between the bead baseline and a position indicating the maximum width of the tire 34 is from 0.7 to 1.3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire. Specifically, the present invention relates to a pneumatic tire whose side is decorated with characters colored in white or the like.

  FIG. 3 shows a conventional pneumatic tire 2. In FIG. 3, 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. 3, the alternate long and short dash line CL represents the equator plane of the tire 2.

  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, and a pair of chafers 18.

  In the tire 2, the clinch 8 is positioned substantially inside the sidewall 6 in the radial direction. The bead 10 is located inside the clinch 8 in the axial direction. The carcass 12 includes two carcass plies 20. These carcass plies 20 are folded around the bead 10 from the inner side to the outer side in the axial direction.

  The bead 10 includes a core 22 and an apex 24 that extends radially outward from the core 22. The apex 24 is made of a highly hard crosslinked rubber.

  In FIG. 3, the double-pointed arrow La represents the length of the apex 24. The length La of the apex 24 is normally set to 40 mm to 50 mm.

  A decorative portion 26 is provided on a side surface of the tire 2. The decorative portion 26 protrudes outward in the axial direction. The decoration part 26 includes a mark 28 colored in white.

  In FIG. 3, a dotted line WL represents a side profile obtained when the decorative portion 26 is not provided. The maximum width in the axial direction of the tire 2 is obtained based on the profile WL. A symbol PW represents a specific position on the profile WL. The tire 2 has a maximum width at the position PW. As is apparent from FIG. 3, the surface of the mark 28 is located immediately above the position PW where the tire 2 exhibits the maximum width.

  In the tire 2, the sidewall 6 includes a black main body 30 and a white colored body 32. As apparent from FIG. 3, the colored body 32 is embedded in the main body 30. This colored body 32 constitutes the mark 28.

  The tire 2 having such a decorative portion 26 is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2013-86666 and 2013-75549.

JP2013-86666A JP 2013-75549 A

  The main body 30 of the sidewall 6 usually contains an amine-based antioxidant. This is because this anti-aging agent is excellent in the antioxidant effect and the like. However, this anti-aging agent has a problem that it is discolored by the action of ultraviolet rays. For this reason, an amine anti-aging agent is not used for the colored body 32 of the sidewall 6. In general, a phenolic anti-aging agent is used for the colored body 32 from the viewpoint of stain resistance.

  The anti-aging agent blended in the rubber moves from the inside of the rubber toward the outside with the passage of time. For this reason, the anti-aging agent mix | blended with the main body 30 may transfer to the colored body 32, and may precipitate on the surface of this colored body 32, ie, the mark 28. FIG. In this case, the deposited antioxidant is discolored by the action of ultraviolet rays. This discoloration damages the color of the mark 28. The tire 2 having the contaminated mark 28 is inferior in appearance quality.

  In order to prevent migration of the anti-aging agent, the colored body 32 needs to have a certain thickness. However, since the colored body 32 is softer than the main body 30, the use of the colored body 32 having a large thickness may impair the performance of the tire 2.

  The tire 2 is stored in a warehouse or the like after it is manufactured until it is attached to the vehicle. In this storage, for example, as shown in FIG. 4, a plurality of tires 2 are piled up with one side face up. In FIG. 4, the second tire 2b is stacked on the first tire 2a. A third tire 2c is stacked on the second tire 2b.

  FIG. 5 schematically shows that the first tire 2a and the second tire 2b are in contact with each other. As shown in FIG. 5, when the tires 2 shown in FIG. 3 are stacked, substantially the entire surface of the mark 28 of the first tire 2a is in contact with the sidewall 6 of the second tire 2b. Resulting in. As described above, the antioxidant contained in the rubber moves from the inside of the rubber toward the outside as time passes. For this reason, an anti-aging agent may deposit on the surface of the sidewall 6 of the second tire 2b during storage, and the deposited anti-aging agent may adhere to the mark 28 of the first tire 2a. An anti-aging agent is deposited on the surface of the mark 28 of the first tire 2a also from the inside thereof. In this case, the anti-aging agent may be present at a high concentration on the surface of the mark 28. The tire 2 stored in a flat stack has a problem that the mark 28 is easily discolored.

  The inventors measured the strain of the first tire 2a in a flat stacked state by analysis using a finite element method (FEM). As a result, it has been confirmed that the distortion of the tire 2 shown in FIG. 3 is maximized at the point indicated by the symbol PS. From this result, the maximum strain position PS is located near the maximum width position PW where the mark 28 is provided, which encourages the contact between the mark 28 of the first tire 2a and the sidewall 6 of the second tire 2b. It is expected that

  An object of the present invention is to provide a pneumatic tire that maintains a good appearance even when stored in a flat state.

  The pneumatic tire according to the present invention includes a decorative portion that protrudes outward in the axial direction on a side surface thereof. The decorative part includes colored marks. The surface of the mark is located immediately above the position showing the maximum width in the axial direction.

  The tire includes a tread, a pair of sidewalls, a pair of clinches, a pair of beads, a carcass, and a pair of fillers. Each sidewall extends substantially inward in the radial direction from the end of the tread. The sidewall is composed of a main body and a colored body that is embedded in the main body and forms the mark. Each clinch extends substantially inward in the radial direction from the end of the sidewall. Each bead is located on the inner side in the axial direction than the clinch. The bead includes a core and an apex that extends radially outward from the core. The carcass is bridged between one bead and the other bead along the inside of the tread, the sidewall, and the clinch. Each filler extends in the radial direction between the carcass, the sidewall and the clinch. The inner end of the filler is located radially inward from the outer end of the apex. The ratio of the height in the radial direction from the bead base line to the outer end of the filler to the height in the radial direction from the bead base line to the position showing the maximum width is 0.7 or more and 1.3 or less.

  Preferably, in this pneumatic tire, the complex elastic modulus of the filler measured at a temperature of 70 ° C. is 20 MPa or more.

  Preferably, in the pneumatic tire, the apex has a length of 10 mm to 30 mm.

  In the pneumatic tire according to the present invention, a filler extending in the radial direction is provided between the carcass, the sidewall, and the clinch. The outer end of the filler is located near the position where the tire shows the maximum width. When two or more of these tires are stacked, that is, when the second tire is stacked on the first tire and the third tire is stacked on the second tire, the distortion generated in the first tire is maximum near the buttress. It becomes. For this reason, when the sidewall of the second tire urges the decorative portion of the first tire inward in the axial direction, the first tire is deformed around the buttress. This deformation contributes to a reduction in the contact pressure between the mark of the first tire and the sidewall of the second tire. In this tire, the mark of the first tire does not sufficiently contact the sidewall of the second tire. In this tire, even if an anti-aging agent is deposited on the surface of the sidewall of the second tire, the anti-aging agent is prevented from adhering to the mark of the first tire. In this tire, the color of the mark is maintained even when stored in a flat state. According to the present invention, it is possible to obtain a pneumatic tire that maintains a good appearance even when stored in a flat state.

FIG. 1 is a cross-sectional view showing a part of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the contact state of the tire when a plurality of the tires of FIG. 1 are stacked. FIG. 3 is a cross-sectional view showing a part of a conventional pneumatic tire. FIG. 4 is a front view showing a state where a plurality of tires are stacked. FIG. 5 is a schematic view showing a contact state of the tire when a plurality of the tires of FIG. 3 are stacked.

  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 34. In FIG. 1, the vertical direction is the radial direction of the tire 34, the horizontal direction is the axial direction of the tire 34, and the direction perpendicular to the paper surface is the circumferential direction of the tire 34. In FIG. 1, an alternate long and short dash line CL represents the equator plane of the tire 34. The shape of the tire 34 is symmetrical with respect to the equator plane except for the tread pattern.

  The tire 34 is mounted on a small truck. The tire 34 corresponds to a small truck tire that is a target of Chapter B of the JATMA standard. In addition, when this tire 34 is comprised so that it may correspond to the tire for passenger cars to which the Chapter A of JATMA specification makes object, it is mounted | worn with a passenger car.

  The tire 34 includes a decorative portion 36 on the side surface. The decoration part 36 protrudes outward in the axial direction. The decoration part 36 includes a colored mark 38. In the tire 34, the color of the mark 38 is white. The radial length of the decorative portion 36, that is, the radial length from the inner edge 40 to the outer edge 42 of the decorative portion 36 is usually 15 mm or greater and 30 mm or less.

  In FIG. 1, a dotted line WL represents a profile of a side surface obtained when there is no decorative portion 36. The maximum width in the axial direction of the tire 34 is obtained based on the profile WL. A symbol PW represents a specific position on the profile WL. The tire 34 has a maximum width at the position PW. As apparent from FIG. 1, in the tire 34, the surface of the mark 38 is located immediately above the position PW indicating the maximum width in the axial direction.

  The tire 34 includes a tread 44, a pair of sidewalls 46, a pair of clinch 48, a pair of beads 50, a carcass 52, a belt 54, an inner liner 56, a pair of chafers 58, and a pair of fillers 60. The tire 34 is a tubeless type.

  The tread 44 has a shape protruding outward in the radial direction. The tread 44 forms a tread surface 62 that contacts the road surface. A groove 64 is carved in the tread 44. The groove 64 forms a tread pattern. The tread 44 has a base layer 66 and a cap layer 68. The cap layer 68 is located on the radially outer side of the base layer 66. The cap layer 68 is laminated on the base layer 66. The base layer 66 is made of a crosslinked rubber having excellent adhesiveness. A typical base rubber of the base layer 66 is natural rubber. The cap layer 68 is made of a crosslinked rubber having excellent wear resistance, heat resistance, and grip properties.

  Each sidewall 46 extends substantially inward in the radial direction from the end of the tread 44. This sidewall 46 is joined to the tread 44. This sidewall 46 is also joined to a clinch 48. The sidewall 46 is made of a crosslinked rubber having excellent cut resistance and weather resistance. This sidewall 46 prevents the carcass 52 from being damaged.

  In the tire 34, the sidewall 46 includes a main body 70 and a colored body 72 that constitutes the mark 38 described above. As is clear from FIG. 1, the colored body 72 is embedded in the main body 70.

  In FIG. 1, the symbol Pd <b> 1 represents the radial outer edge 42 of the decorative portion 36. A solid line Ld1 is a normal line of the profile WL on the side surface passing through the outer edge Pd1. A symbol Ps1 is an intersection of the normal line Ld1 and the profile WL. Reference symbol Pd2 represents the inner edge 40 in the radial direction of the decorative portion 36. A solid line Ld2 is a normal line of the profile WL on the side surface that passes through the outer edge Pd2. A symbol Ps2 is an intersection of the normal line Ld2 and the profile WL.

  As is apparent from FIG. 1, the outer edge 74 of the colored body 72 is located radially outside the intersection point Ps1. The inner edge 76 of the colored body 72 is located on the radially inner side with respect to the intersection point Ps2. The length from the intersection Ps1 to the outer edge 74 of the colored body 72 is usually 10 mm or more and 20 mm or less. The length from the intersection Ps2 to the inner edge 76 of the colored body 72 is usually 10 mm or more and 20 mm or less.

  In the tire 34, the main body 70 is formed by crosslinking a rubber composition. A preferred base rubber of the rubber composition is a diene rubber. Specific examples of the diene rubber include natural rubber (NR), polyisoprene (IR), polybutadiene (BR), acrylonitrile-butadiene copolymer (NBR), and polychloroprene (CR). Two or more kinds of rubbers may be used in combination.

  The rubber composition of the main body 70 includes a reinforcing agent. A typical reinforcing agent is carbon black. FEF, GPF, HAF, ISAF, SAF, etc. can be used. Silica may be used together with carbon black from the viewpoint of suppressing heat generation due to deformation. In this case, dry silica and wet silica can be used. From the viewpoint of the strength of the main body 70, the amount of the reinforcing agent is preferably 5 parts by mass or more with respect to 100 parts by mass of the base rubber. In light of the softness of the main body 70, the amount of the reinforcing agent is preferably 50 parts by mass or less. Carbon black is black. The main body 70 including the carbon black is black.

  The rubber composition of the main body 70 includes an anti-aging agent. From the viewpoint of the antioxidant effect, the rubber composition of the main body 70 contains an amine-based antioxidant. Examples of the amine-based antioxidant include naphthylamine-based antioxidants such as phenyl-α-naphthylamine, diphenylamine-based antioxidants such as octylated diphenylamine and 4,4′-bis (α, α′-dimethylbenzyl) diphenylamine, And N-isopropyl-N′-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N, N′-di-2-naphthyl-p-phenylene Examples include p-phenylenediamine-based antioxidants such as diamines. The blending amount of the anti-aging agent is usually 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the base rubber.

  In addition to the reinforcing agent and the anti-aging agent, a crosslinking agent, a softening agent, stearic acid, zinc oxide, wax, a crosslinking aid, and the like are added to the rubber composition of the main body 70 as necessary.

  In the tire 34, the colored body 72 is formed by crosslinking a rubber composition. A preferred base rubber of the rubber composition is a diene rubber. The diene rubber described above with respect to the main body 70 can also be used for the colored body 72.

  The rubber composition of the colored body 72 includes a reinforcing agent. Since the colored body 72 is colored, a white reinforcing agent is used. In the rubber composition of the colored body 72, the above-described carbon black is not used except for coloring. Examples of the white reinforcing agent include silica, magnesium carbonate, and calcium carbonate. White fillers such as alumina white and barium sulfate may be used as a reinforcing agent. From the viewpoint of the strength of the colored body 72, the amount of the reinforcing agent is preferably 5 parts by mass or more with respect to 100 parts by mass of the base rubber. In light of the softness and mass of the colored body 72, the amount of the reinforcing agent is preferably 80 parts by mass or less.

  The rubber composition of the colored body 72 includes an anti-aging agent. From the viewpoint of non-contamination, the rubber composition of the main body 70 includes a phenolic anti-aging agent. Examples of the phenol-based anti-aging agent include monophenol-based anti-aging agents such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol, and tetrakis- [methylene-3- (3 ', 5' -Di-t-butyl-4'-hydroxyphenyl) propionate] Bis such as methane, tris, and polyphenol antioxidants are exemplified. The amount of the anti-aging agent is usually 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the base rubber.

  In addition to the reinforcing agent and anti-aging agent, the rubber composition of the colored body 72 includes a cross-linking agent, a softening agent, stearic acid, zinc oxide, wax, a cross-linking aid, etc. in consideration of non-contamination, and is added as necessary. Is done.

  Each clinch 48 extends substantially inward in the radial direction from the end of the sidewall 46. The clinch 48 is located outside the bead 50 and the carcass 52 in the axial direction. The clinch 48 is made of a crosslinked rubber having excellent wear resistance. The clinch 48 contacts the flange of a rim (not shown).

  Each bead 50 is located inward of the clinch 48 in the axial direction. The bead 50 includes a core 78 and an apex 80 that extends radially outward from the core 78. The core 78 is ring-shaped and includes a wound non-stretchable wire. A typical material for the wire is steel. The apex 80 is tapered outward in the radial direction. The apex 80 is made of a highly hard crosslinked rubber.

  The carcass 52 includes a first carcass ply 82 and a second carcass ply 84. The first carcass ply 82 and the second carcass ply 84 are bridged between the beads 50 on both sides. The first carcass ply 82 and the second carcass ply 84 are along the inside of the tread 44, the sidewall 46, and the clinch 48. The first carcass ply 82 is folded around the core 78 from the inner side to the outer side in the axial direction. By this folding, the first carcass ply 82 is formed with a first main portion 86 and a first folding portion 88. The second carcass ply 84 is folded around the core 78 from the inner side to the outer side in the axial direction. By this folding, the second carcass ply 84 is formed with a second main portion 90 and a second folding portion 92. The end of the first folded portion 88 is located outside the end of the second folded portion 92 in the radial direction.

  Each of the first carcass ply 82 and the second carcass ply 84 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 52 has a radial structure. The cord is made of organic fiber. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers. The carcass 52 may be formed from one carcass ply. The carcass 52 may be formed of three or more carcass plies.

  The belt 54 is located on the inner side in the radial direction of the tread 44. The belt 54 is laminated with the carcass 52. The belt 54 reinforces the carcass 52. The belt 54 includes an inner layer 94 and an outer layer 96. As apparent from FIG. 1, the width of the inner layer 94 is slightly larger than the width of the outer layer 96 in the axial direction. Although not shown, each of the inner layer 94 and the outer layer 96 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 general absolute value of the tilt angle is 10 ° or more and 35 ° or less. The inclination direction of the cord of the inner layer 94 with respect to the equator plane is opposite to the inclination direction of the cord of the outer layer 96 with respect to the equator plane. A preferred material for the cord is steel. An organic fiber may be used for the cord. The axial width of the belt 54 is preferably 0.7 times or more the maximum width of the tire 34. The belt 54 may include three or more layers.

  The inner liner 56 is located inside the carcass 52. The inner liner 56 is joined to the inner surface of the carcass 52. The inner liner 56 is made of a crosslinked rubber having excellent air shielding properties. A typical base rubber of the inner liner 56 is butyl rubber or halogenated butyl rubber. The inner liner 56 holds the internal pressure of the tire 34.

  Each chafer 58 is located in the vicinity of the bead 50. When the tire 34 is incorporated into the rim, the chafer 58 contacts the rim. By this contact, the vicinity of the bead 50 is protected. In this embodiment, the chafer 58 is made of cloth and rubber impregnated in the cloth. The chafer 58 may be integrated with the clinch 48. In this case, the material of the chafer 58 is the same as that of the clinch 48.

  Each filler 60 is located inward of the sidewall 46 and the clinch 48 in the axial direction. The filler 60 is located on the outer side in the axial direction than the carcass 52. In the tire 34, the inner end 98 of the filler 60 is located radially inward of the outer end 100 of the apex 80. As shown in FIG. 1, the filler 60 extends radially outward from near the core 78.

  In the tire 34, the filler 60 is formed by crosslinking a rubber composition. In other words, the filler 60 is made of a crosslinked rubber. A preferred base rubber of the rubber composition is a diene rubber. Specific examples of the diene rubber include natural rubber (NR), polyisoprene (IR), polybutadiene (BR), acrylonitrile-butadiene copolymer (NBR), and polychloroprene (CR). Two or more kinds of rubbers may be used in combination.

  The rubber composition of the filler 60 includes a reinforcing agent. A typical reinforcing agent is carbon black. FEF, GPF, HAF, ISAF, SAF, etc. can be used. Silica may be used together with carbon black or in place of carbon black from the viewpoint of suppressing heat generation due to deformation. In this case, dry silica and wet silica can be used. From the viewpoint of the strength of the filler 60, the amount of the reinforcing agent is preferably 5 parts by mass or more with respect to 100 parts by mass of the base rubber. From the viewpoint of the softness of the filler 60, the amount of the reinforcing agent is preferably 50 parts by mass or less.

  A crosslinking agent, a softening agent, stearic acid, zinc oxide, an antiaging agent, a wax, a crosslinking aid, and the like are added to the rubber composition of the filler 60 as necessary.

  As described above, the sidewall 46 of the tire 34 includes the main body 70 and the colored body 72. From the viewpoint of hue, the colored body 72 having a restriction on the reinforcing agent that can be employed is softer than the main body 70 without the restriction. In the tire 34, a soft colored body 72 is disposed in the vicinity of the position PW.

  In the tire 34, a filler 60 extending in the radial direction is provided between the carcass 52, the sidewall 46, and the clinch 48. The outer end 102 of the filler 60 is located near a position PW where the tire 34 exhibits the maximum width. The filler 60 is harder than the colored body 72. The presence of the filler 60 affects the rigidity of the side wall 46 portion of the tire 34.

  From the analysis by a finite element method (FEM), when a plurality of tires 34 are stacked, that is, the second tire 34b is stacked on the first tire 34a, and the second tire 34b is stacked on the second tire 34b. When the three tires 34c are stacked, it has been confirmed that the distortion generated in the first tire 34a is maximized at the position indicated by the symbol PS in FIG. 1, that is, in the vicinity of the buttress. In the conventional tire 2 shown in FIG. 3 in which the filler 60 is not provided, it is confirmed that the distortion generated in the first tire 2a is maximized near the maximum width position PW. The presence of the filler 60 affects the position of strain caused by the action of the load. In other words, in the tire 34, by providing the filler 60, the strain generated by the action of the load is controlled so that the strain generated in the first tire 34a is maximized in the vicinity of the buttress.

  As described above, when a plurality of tires 34 are stacked, the distortion generated in the first tire 34a is maximized in the vicinity of the buttress. For this reason, when the sidewall 46 of the second tire 34b urges the decorative portion 36 of the first tire 34a inward in the axial direction, the first tire 34a is deformed around the buttress.

  FIG. 2 schematically shows a state where the first tire 34a and the second tire 34b are in contact with each other. Since the first tire 34a is deformed around the buttress, the mark 38 of the first tire 34a does not sufficiently contact the sidewall 46 of the second tire 34b, as shown in FIG. This deformation contributes to a reduction in contact pressure between the mark 38 of the first tire 34a and the sidewall 46 of the second tire 34b. In the tire 34, even if the anti-aging agent is deposited on the surface of the sidewall 46 of the second tire 34b, the deposited anti-aging agent is prevented from adhering to the mark 38 of the first tire 34a. Since the amount of the anti-aging agent present on the surface of the mark 38 is moderately suppressed, even if the tire 34 is stored in a flat state, the color of the mark 38 is maintained. According to the present invention, it is possible to obtain the pneumatic tire 34 that maintains a good appearance even when stored in a flat state. When the pressure sensitive sheet was sandwiched between the first tire 34a and the second tire 34b and the contact pressure was measured, it was confirmed that the contact pressure at the mark 38 was less than half the contact pressure near the buttress. ing.

  In FIG. 1, the symbol P10 represents a specific position on the profile WL. This position P10 is 10 mm away from the intersection Ps1. This position P10 is a specific position on the profile WL that is 10 mm away from the intersection Ps1. Reference numeral P15 represents a specific position different from the position P10 on the profile WL. This position P15 is 15 mm away from the intersection Ps1. This position P15 is a specific position on the profile WL that is 15 mm away from the intersection Ps1.

  As shown in FIG. 1, in the tire 34, the position PS having the maximum strain is preferably located radially outside the position P15 in the radial direction. Thereby, the stacked tire 34 is configured to be deformed around its buttress vicinity. As in the tire 34 shown in FIG. 1, the deformation is such that the outer edge 74 of the colored body 72 coincides with the position P15 in the radial direction, or the outer edge 74 is located radially inward from the position P15. In case you are prompted. In the tire 34, the anti-aging agent deposited on the surface of the sidewall 46 of another tire 34 is effectively prevented from adhering to the surface of the mark 38. Since the amount of anti-aging agent present on the surface of the mark 38 is moderately suppressed, the tire 34 retains the color of the mark 38 even when stored in a flat state. In the tire 34, a good appearance is maintained.

  In FIG. 1, a double-headed arrow EW represents the thickness of the decorative portion 36 at the maximum width position PW. A double-headed arrow E10 represents the thickness of the colored body 72 at the position P10.

  As described above, in the tire 34, even if an anti-aging agent is deposited on the surface of the sidewall 46 of the second tire 34b, the deposited anti-aging agent is prevented from adhering to the mark 38 of the first tire 34a. Is done. In the tire 34, since the amount of the anti-aging agent present on the surface of the mark 38 is moderately suppressed, the thin colored body 72 can be employed within a range in which the color of the mark 38 can be maintained. Specifically, in the tire 34, the thickness EW can be set to 5 mm or less. It is possible to set the thickness E10 to 1.7 mm or less. The adoption of the thin colored body 72 contributes to a reduction in the amount of the colored body 72 that constitutes the sidewall 46. In the tire 34, the colored body 72 is effectively prevented from affecting the performance such as steering stability.

  In FIG. 1, a solid line BBL is a bead base line. The bead base line is a line that defines the rim diameter (see JATMA) of the rim. The bead baseline extends in the axial direction. A double arrow HW represents a height in the radial direction from the bead base line to a position PW where the tire 34 exhibits the maximum width. A double-headed arrow HF represents the radial height from the bead base line to the outer end 102 of the filler 60.

  In the tire 34, the ratio of the height HF to the height HW is not less than 0.7 and not more than 1.3. By setting this ratio to be 0.7 or more, the distortion of the tire 34 stored in a flat stack is maximized in the vicinity of the buttress. The tire 34 is configured to deform around its buttress vicinity. In this tire 34, the anti-aging agent deposited on the surface of the sidewall 46 of another tire 34 is effectively prevented from adhering to the surface of the mark 38. Since the amount of anti-aging agent present on the surface of the mark 38 is moderately suppressed, the tire 34 retains the color of the mark 38 even when stored in a flat state. In the tire 34, a good appearance is maintained. From this viewpoint, this ratio is preferably 0.8 or more, and more preferably 0.9 or more. By setting this ratio to 1.3 or less, the rigidity of the entire tire 34 is appropriately maintained. In the tire 34, the deformation around the buttress is maintained. Even in this case, the anti-aging agent deposited on the surface of the sidewall 46 of another tire 34 is effectively prevented from adhering to the surface of the mark 38. Since the amount of anti-aging agent present on the surface of the mark 38 is moderately suppressed, the tire 34 retains the color of the mark 38 even when stored in a flat state. In the tire 34, a good appearance is maintained. Further, since the influence on the rigidity by the filler 60 is suppressed, the tire 34 flexes flexibly in the running state. This bending contributes to a reduction in rolling resistance. The tire 34 is excellent in fuel efficiency. From this viewpoint, the ratio is preferably 1.2 or less, and more preferably 1.1 or less.

  As described above, in the tire 34, the inner end 98 of the filler 60 is located radially inward of the outer end 100 of the apex 80. In other words, in this tire 34, the portion of the inner end 98 of the filler 60 overlaps with the bead 50 in the axial direction. The filler 60 effectively acts to resist deformation of the bead 50 portion. The filler 60 contributes to the flexible bending of the bead 50 portion. The tire 34 is excellent in handling stability.

  In the tire 34, the complex elastic modulus Ef of the filler 60 measured at 70 ° C. is preferably 20 MPa or more. This effectively functions to control the position PS of the maximum strain generated in the tire 34 in which the filler 60 is stacked. The tire 34 including the filler 60 is configured to be deformed around its buttress vicinity. In this tire 34, the anti-aging agent deposited on the surface of the sidewall 46 of another tire 34 is effectively prevented from adhering to the surface of the mark 38. Since the amount of anti-aging agent present on the surface of the mark 38 is moderately suppressed, the tire 34 retains the color of the mark 38 even when stored in a flat state. In the tire 34, a good appearance is maintained. In this respect, the complex elastic modulus Ef is preferably 25 MPa or more.

In the present invention, the complex elastic modulus Ef of the filler 60 measured at 70 ° C. is a viscoelastic spectrometer (trade name manufactured by Iwamoto Seisakusho Co., Ltd.) according to the following measurement conditions in accordance with the provisions of “JIS K 6394”. “VESF-3”). In this measurement, a plate-shaped test piece (length = 45 mm, width = 4 mm, thickness = 2 mm) is formed from the rubber composition of the filler 60. This test piece is used for measurement.
Initial strain: 10%
Amplitude: ± 2.0%
Frequency: 10Hz
Deformation mode: Tensile
Measurement temperature: 70 ° C

  In the tire 34, the complex elastic modulus Ef of the filler 60 measured at 70 ° C. is preferably 40 MPa or less. Thereby, the influence on the rigidity of the tire 34 by the filler 60 is suppressed effectively. In the tire 34, good riding comfort is maintained. From this viewpoint, the complex elastic modulus Ef is more preferably 35 MPa or less.

  In FIG. 1, the double arrow La is the length of the apex 80. This length La is represented by the length from the axial center (reference numeral Pa in FIG. 1) of the bottom surface of the apex 80 to the outer end 100 thereof.

  In the tire 34, the length La is preferably 10 mm or greater and 30 mm or less. By setting this length La to 10 mm or more, the apex 80 appropriately contributes to the rigidity of the tire 34. In the tire 34, the apex 80 effectively acts so as to resist deformation of the bead 50 portion in the running state. The apex 80 contributes to the flexible bending of the bead 50 portion. The tire 34 is excellent in handling stability. By setting the length La to 30 mm or less, the influence on the mass by the apex 80 is effectively suppressed. The apex 80 cooperates with the filler 60 and effectively contributes to the rigidity of the tire 34. The tire 34 is excellent in handling stability. Since the first folded portion 88 and the second folded portion 92 of the carcass 52 are disposed at positions close to the inner surface of the tire 34, distortion may concentrate on the first folded portion 88 and the second folded portion 92 in the running state. Is prevented. The arrangement of the first folded portion 88 and the second folded portion 92 contributes to improvement in durability.

  In the present invention, the dimension and angle of each member of the tire 34 are measured in a state where the tire 34 is incorporated in a normal rim and the tire 34 is filled with air so as to have a normal internal pressure. During the measurement, no load is applied to the tire 34. In the present specification, the normal rim means a rim defined in a standard on which the tire 34 is based. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In this specification, the normal internal pressure means an internal pressure defined in a standard on which the tire 34 is based. “Maximum air pressure” in JATMA standard, “Maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in TRA standard, and “INFLATION PRESSURE” in ETRTO standard are normal internal pressures. In the case of the passenger car tire 34, the dimensions and angle are measured in a state where the internal pressure is 180 kPa. The same applies to the tire 2 described above.

  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 shown in FIG. 1 was manufactured. The size of this tire is 195 / 80R15. The apex length La was set to 20 mm. The complex elastic modulus Ef of the filler measured at 70 ° C. was 30 MPa. The ratio of the height HF to the height HW (HF / HW) was 1.0.

  The sidewall of Example 1 is composed of a main body and a colored body. The rubber composition of the main body contains an amine-based anti-aging agent, but the colored rubber composition does not contain this amine-based anti-aging agent.

[Comparative Example 1]
Comparative Example 1 is a conventional tire. The comparative example 1 has the configuration shown in FIG. In this comparative example 1, the apex length La was 45 mm. In Comparative Example 1, no filler is provided. The specification of the sidewall of this comparative example 1 is equivalent to that of the example 1.

[Example 2-4]
A tire of Example 2-4 was obtained in the same manner as Example 1 except that the complex elastic modulus Ef of the filler was as shown in Table 1 below.

[Example 5-10 and Comparative Example 2-3]
Tires of Example 5-10 and Comparative Example 2-3 were obtained in the same manner as Example 1 except that the ratio (HF / HW) was as shown in Tables 2 and 3 below.

[Contamination]
Three tires were stacked and stored in a warehouse for 2 weeks. In this flat stack, the second tire was stacked on the first tire, and the third tire was stacked on the second tire. The temperature in the warehouse during storage was in the range of 30 ° C to 40 ° C. After storage, the side surface (the surface of the mark) of the first tire was irradiated with ultraviolet rays in the range of 300 to 400 nm using an ultraviolet irradiation device (light source = xenon lamp). The intensity of the light source was set to 20W. The irradiation time was set to 24 hours. After irradiation, the color of the mark was observed. The degree of discoloration (darkness) was rated according to the following criteria.
BAD = Mark is discolored brown SOSO = Appearance quality is not a problem, but mark is slightly discolored GOOD = Mark is not discolored

  Five assessors rated the treated tires. BAD is 1 point, SOSO is 2 points, and GOOD is 3 points, and an average value is obtained. This average value is shown in Table 1-3 below. The larger the value, the better, that is, the discoloration of the mark is suppressed. The average value of 2.0 or more was regarded as the acceptance criterion as a product.

  As shown in Table 1-3, the tire of the example has a higher evaluation than the tire of the comparative example. From this evaluation result, the superiority of the present invention is clear.

  The strain position control technique using the filler described above can be applied to various tires.

2, 34 ... Tire 4, 44 ... Tread 6, 46 ... Sidewall 8, 48 ... Clinch 10, 50 ... Bead 12, 52 ... Carcass 14, 54 ... Belt 22, 78 ... Core 24, 80 ... Apex 26, 36 ... Decoration part 28, 38 ... Mark 30, 70 ... Main body 32, 72 ... Colored body 60 ... Filler 98 ... Inner end of filler 60 100 ... Outer end of apex 80 102 ... Outer end of filler 60

Claims (3)

A decorative portion protruding outward in the axial direction is provided on the side surface, the decorative portion includes a colored mark, and the surface of the mark is located immediately above the position indicating the maximum width in the axial direction. Tires,
The tire includes a tread, a pair of sidewalls, a pair of clinch, a pair of beads, a carcass, and a pair of fillers,
Each sidewall extends radially inward from the end of the tread,
This sidewall is composed of a main body and a colored body that is embedded in the main body and constitutes the mark,
Each clinch extends substantially inward in the radial direction from the end of the sidewall,
Each bead is located axially inside from the clinch,
The bead includes a core and an apex extending radially outward from the core,
The carcass is bridged between one bead and the other bead along the inside of the tread, the sidewall and the clinch,
Each filler extends in the radial direction between the carcass, the sidewalls and the clinch,
The inner end of the filler is located radially inward from the outer end of the apex,
Air in which the ratio of the radial height from the bead base line to the outer end of the filler to the radial height from the bead base line to the position indicating the maximum width is 0.7 or more and 1.3 or less. Enter tire.   The pneumatic tire according to claim 1, wherein a complex elastic modulus of the filler measured at a temperature of 70 ° C is 20 MPa or more.   The pneumatic tire according to claim 1 or 2, wherein the apex has a length of 10 mm to 30 mm.

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