JP2009160952A - Pneumatic radial tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic radial tire 2 highly rigid and obtainable without involving an increase in mass. <P>SOLUTION: The tire 2 includes a tread 4, a pair of beads 6, a carcass 8 laid across the beads 6, a belt 10 located outside the carcass 8, a pair of chafers 16 folded around the beads 6, and a pair of side plies 18 located outside the carcass 8. The bead 6 has a core 24 and an apex 26. The side ply 18 is located radially outside a portion located axially outside the chafer 16. An end 54 located radially outside the side ply 18 is located between the tread 4 and the belt 10. An end 52 located radially inside the side ply 18 is located radially inside a position indicating a maximum width and radially inside an end 28 of the apex. The side ply 18 contains fibers and rubber covering the fibers. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pneumatic radial tire.

  A tire is configured by combining a number of members such as a tread, a sidewall, a bead, a carcass, and a belt. The performance of the tire is improved by adjusting the specifications and combinations of these members.

  The lateral rigidity of the tire can contribute to the generation of cornering force. A tire capable of generating a large cornering force during turning can turn at high speed and stably. Such a tire is excellent in handling stability.

  Japanese Unexamined Patent Publication No. 2007-168526 discloses a tire that has high rigidity and can be obtained at low cost. In this tire, the sidewall includes a side ply including a fiber and rubber covering the fiber.

  JP-A-6-199114 discloses a tire that is excellent in durability and can be obtained at low cost. In this tire, a canvas made of stretchable organic fibers is disposed on the outer surface of the sidewall portion.

Japanese Laid-Open Patent Publication No. 2006-160106 discloses a tire excellent in handling stability and high-speed durability. In this tire, a rubber reinforcing layer made of hard rubber and a fiber reinforcing layer made of canvas cloth are provided between the carcass ply and the side wall rubber.
JP 2007-168526 A JP-A-6-199114 JP 2006-160106 A

  In a tire having a large number of plies constituting the carcass, the side wall portion can be reinforced. This tire has a large lateral rigidity. Since this tire can generate a large cornering force, it has excellent steering stability. However, the mass of this tire is large. Such a tire hinders fuel consumption performance.

  In the tire in which the apex constituting the bead has a large height, the side wall portion can be reinforced. Since this tire has a large lateral rigidity, it has excellent steering stability. However, the mass of this tire is large. Such a tire hinders fuel consumption performance.

  The tire in which the reinforcing filler is added to the side wall portion has a large lateral rigidity. This tire is excellent in handling stability. However, the mass of this tire is large. Such a tire hinders fuel consumption performance. It is difficult to obtain a tire having high rigidity without increasing the mass.

  An object of the present invention is to provide a pneumatic tire which has high rigidity and can be obtained without an increase in mass.

  A pneumatic radial tire according to the present invention includes a tread whose outer surface forms a tread surface, a pair of beads, a carcass spanned between both beads, a belt positioned radially outward of the carcass, A pair of chafers that are folded back from the inner side toward the outer side in the axial direction, and a pair of side plies positioned outside the carcass are provided. The bead includes a core and an apex extending radially outward from the core. The side ply is located on the radially outer side of the portion located on the outer side in the axial direction of the chafer. The side ply extends radially outward along the carcass. The end located on the radially outer side of the side ply is located between the tread and the belt. The end located on the radially inner side of the side ply is located on the radially inner side of the position indicating the maximum tire width, and is located on the radially inner side of the tip of the apex. The side ply includes a fiber and rubber covering the fiber.

  Preferably, in this tire, the side ply is laminated on the carcass.

  Preferably, in this tire, the side ply includes a plurality of side cords made of the fibers and arranged in parallel with each other. The belt includes a number of belt cords arranged in parallel. The absolute value of the crossing angle between the side cord and the belt cord is not less than 45 ° and not more than 90 °.

  Preferably, in the tire, the side ply includes a woven fabric in which the fibers are woven and a rubber impregnated in the woven fabric.

  A pneumatic radial tire according to another embodiment of the present invention includes a tread whose outer surface forms a tread surface, a pair of beads, a carcass spanned between both beads, and a belt positioned radially outward of the carcass. And a pair of chafers folded around the bead from the inner side to the outer side in the axial direction, and a pair of side plies positioned outside the carcass. The side ply is located on the radially outer side of the portion located on the outer side in the axial direction of the chafer. The side ply extends radially outward along the carcass. The end located on the radially outer side of the side ply is located between the tread and the belt. The side ply and the chafer are integrally formed. The side ply and the chafer are made of a fabric in which fibers are woven and a rubber impregnated in the fabric.

  In this tire, the side ply can contribute to the rigidity of the tire. Since the tire has high rigidity, a large cornering force can be generated. This tire is excellent in handling stability. The end located on the radially outer side of the side ply is located between the tread and the belt. The side ply covers the end of the belt. This side ply can restrain the belt. This tire is excellent in durability and high-speed stability. The side ply includes a fiber and rubber covering the fiber. By using this side ply, a tire having high rigidity can be obtained without increasing the mass.

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

  FIG. 1 is a cross-sectional view showing a part of a pneumatic tire 2 according to an embodiment of the present invention. In FIG. 1, the vertical direction is the radial direction, the horizontal direction is the axial direction, and the direction perpendicular to the paper surface is the circumferential direction. The tire 2 has a substantially left-right symmetric shape centered on a one-dot chain line CL in FIG. This alternate long and short dash line CL represents the equator plane of the tire 2. The equatorial plane CL extends in the circumferential direction. The point PA is a position indicating the maximum width of the tire 2. The tire 2 includes a tread 4, a bead 6, a carcass 8, a belt 10, a band 12, an inner liner 14, a chafer 16, a side ply 18, and a strip 20. The tire 2 is a tubeless type. The tire 2 is mounted on a passenger car.

  The tread 4 is made of a crosslinked rubber having excellent wear resistance. The tread 4 has a shape protruding outward in the radial direction. The tread 4 includes a tread surface 22. The tread surface 22 is in contact with the road surface. In the tire 2, no groove is formed on the tread surface 22. The tire 2 is a so-called slick tire. The tread surface 22 may include a tread pattern including grooves, blocks, and the like.

  The bead 6 is located on the inner side in the radial direction of the tread 4. The bead 6 includes a core 24 and an apex 26 that extends radially outward from the core 24. The core 24 has a ring shape. The core 24 includes a plurality of non-stretchable wires (typically steel wires). The apex 26 is tapered outward in the radial direction. The apex 26 is made of a highly hard crosslinked rubber. As shown in the drawing, in the tire 2, the tip 28 of the apex 26 is located radially inward of the point PA. The tip 28 may be located outside the point PA in the radial direction.

  The carcass 8 includes a ply 30. The ply 30 is along the inside of the tread 4. The ply 30 is bridged between the beads 6 on both sides. The ply 30 is folded around the core 24 from the inner side to the outer side in the axial direction. By this folding, a main portion 32 extending from the equator plane toward the bead 6 and a folding portion 34 that is folded back by the core 24 and extends outward in the radial direction are formed in the ply 30. . As illustrated, the end 36 of the folded portion 34 is located near the end of the tread 4. An end 36 of the folded portion 34 is sandwiched between the main portion 32 and the belt 10. Such a carcass 8 is referred to as a high turn-up (HTU) structure.

  Although not shown, the ply 30 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 usually 70 ° to 90 °. In other words, the carcass 8 has a radial structure. The cord is usually made of organic fibers. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers. A carcass 8 having a bias structure may be employed.

  The belt 10 is located outside the carcass 8 in the radial direction. The belt 10 is laminated with the carcass 8. The belt 10 reinforces the carcass 8. The belt 10 includes an inner layer 38 and an outer layer 40. The inner layer 38 is laminated on the carcass 8. The outer layer 40 is laminated on the inner layer 38. As shown, the end 42 of the inner layer 38 is located axially outside the end 44 of the outer layer 40. The axial width of the inner layer 38 is wider than the axial width of the outer layer 40. In the tire 2, the end 42 of the inner layer 38 is the end of the belt 10. The end 42 of the belt 10 is located in the vicinity of the end of the tread 4.

  Although not shown, each of the inner layer 38 and the outer layer 40 is composed of a large number of belt cords and topping rubbers arranged in parallel. Each belt cord is inclined with respect to the equator plane. The absolute value of the tilt angle is not less than 10 ° and not more than 35 °. The direction of inclination of the belt cord of the inner layer 38 is opposite to the direction of inclination of the belt cord of the outer layer 40. A preferred material for the belt cord is steel. An organic fiber may be used for the belt cord.

  The band 12 covers the belt 10. In the tire 2, the end 46 of the band 12 coincides with the end 42 of the belt 10 in the axial direction. Although not shown, the band 12 is composed of a cord and a topping rubber. The cord extends substantially in the circumferential direction and is wound spirally. The band 12 has a so-called jointless structure. Since the belt 10 is restrained by this cord, the lifting of the belt 10 is suppressed. The cord is usually made of organic fibers. Examples of preferable organic fibers include nylon fibers, polyester fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The inner liner 14 is joined to the inner peripheral surface of the carcass 8. The inner liner 14 is made of a crosslinked rubber. The inner liner 14 is made of rubber having excellent air shielding properties. The inner liner 14 plays a role of maintaining the internal pressure of the tire 2.

  The chafer 16 is located in the vicinity of the bead 6. The chafer 16 extends along the outer surface of the tire 2. The chafer 16 is folded around the bead 6 from the inner side to the outer side in the axial direction. In the chafer 16, an end (outer end) 48 positioned on the outer side in the axial direction is positioned on an outer side in the radial direction of an end (inner end) 50 positioned on the inner side in the axial direction. The outer end 48 is located radially inward of the tip 28 of the apex 26. When the tire 2 is assembled into a rim (not shown), the chafer 16 comes into contact with the rim. By this contact, the vicinity of the bead 6 is protected. The chafer 16 is made of a woven fabric and rubber impregnated in the woven fabric. This fabric consists of a number of warps and a number of wefts. The warp and weft are made of organic fibers. Examples of preferable organic fibers include polyester fibers, polyethylene naphthalate fibers, nylon fibers, and aramid fibers. Such a chafer 16 is called a canvas chafer.

  The side ply 18 is located outside the carcass 8. The side ply 18 is located on the radially outer side of the portion located on the outer side in the axial direction of the chafer 16. An end (inner end) 52 located on the radially inner side of the side ply 18 is located on the radially outer side of the outer end 48 of the chafer 16. The side ply 18 extends radially outward along the carcass 8 from the outer end 48 side of the chafer 16.

  In the tire 2, an end (outer end) 54 located on the radially outer side of the side ply 18 is located on the radially outer side of the band 12. A part of the side ply 18 is laminated on the band 12. The outer end 54 of the side ply 18 is located on the inner side in the axial direction of the end 46 of the band 12. The side ply 18 covers the end 46 of the band 12.

  In the tire 2, the outer end 54 of the side ply 18 is located between the tread 4 and the belt 10. The side ply 18 located on the radially outer side than the buttress 56 of the tire 2 is located on the inner side of the tread 4. The side ply 18 located radially inward from the buttress 56 is located outside the tire 2 in the axial direction. A part of the outer surface 58 of the side ply 18 constitutes the outer surface of the tire 2. In the tire 2, the side ply 18 positioned radially inward from the buttress 56 corresponds to a sidewall. The side ply 18 corresponding to the side wall extends substantially inward in the radial direction from the end of the tread 4. The side ply 18 absorbs an impact from the road surface by bending. Further, the side ply 18 prevents the carcass 8 from being damaged.

  FIG. 2 is a cross-sectional view showing a part of the side ply 18 of the tire 2 of FIG. The side ply 18 includes a large number of side cords 60 arranged in parallel and a topping rubber 62. The side cord 60 is covered with a topping rubber 62. All the side cords 60 have substantially the same diameter. The interval between adjacent side cords 60 is substantially the same.

  In the tire 2, the side cord 60 is made of an organic fiber. Specific examples of the organic fiber include polyester fiber, polyethylene naphthalate fiber, nylon fiber, and aramid fiber. When the cord of the carcass 8 is a nylon fiber, it is preferable that a polyester fiber or a polyethylene naphthalate fiber is used for the cord of the side ply 18 from the viewpoint of the rigidity of the tire 2.

  The tire 2 is manufactured as follows. First, while a large number of side cords 60 are arranged at a predetermined interval, wefts (not shown) are combined with these side cords 60 to weave a woven fabric. This weft can suppress the arrangement disorder of the side cords 60. This weft is thin. Next, the woven fabric is covered with a rubber composition constituting the topping rubber 62 to form the side ply 18. Next, the side ply 18 is supplied to the former. Other members are also supplied to the former. Other members include the inner liner 14, the chafer 16, the ply 30 constituting the carcass 8, the bead 6, the inner layer 38 and the outer layer 40 constituting the belt 10, and the tread 4. These rubber members are assembled in the former to obtain a low cover (also referred to as an uncrosslinked tire). In this assembly, the side ply 18 is attached after the chafer 16 is folded around the bead 6. The process for obtaining this raw cover is referred to as a molding process.

  Next, the raw cover is subjected to a vulcanization process. In the vulcanization process, this raw cover is first put into an opened mold. When thrown, the bladder is contracted. When thrown, the bladder is positioned inside the raw cover. Next, the bladder expands due to gas filling. Due to this expansion, the raw cover is deformed. This deformation is called shaping. Next, the mold is tightened. Next, the internal pressure of the bladder is increased. The raw cover is pressed between the cavity surface of the mold and the outer surface of the bladder. The raw cover is heated by heat conduction from the bladder and the mold. The rubber composition of the raw cover flows by pressurization and heating. The rubber composition causes a crosslinking reaction by heating, and the tire 2 is obtained.

  In the tire 2, the side ply 18 is reinforced by a side cord 60. The side ply 18 can contribute to the rigidity of the tire 2. The tire 2 having high rigidity can generate a large cornering force. The tire 2 is excellent in handling stability. In the tire 2, the side ply 18 includes a fiber and a topping rubber 62 that covers the fiber. The side ply 18 does not affect the mass of the tire 2. By using the side ply 18, the tire 2 having high rigidity can be obtained without increasing the mass.

  As shown in FIG. 1, in the tire 2, another member such as an insulation rubber is not interposed between the carcass 8 and the side ply 18 in a portion corresponding to the sidewall. The side ply 18 is laminated on the carcass 8. In other words, the portion corresponding to the sidewall of the tire 2 is composed of only the side ply 18. In the tire 2, mass reduction is achieved.

  As described above, in the tire 2, the side ply 18 is positioned on the outer side in the axial direction of the tire 2 in a portion corresponding to the sidewall. In the tire 2, the side cord 60 included in the side ply 18 can suppress the flow of the rubber composition in the vulcanization process. This suppression of flow can suppress the generation of bears and the like. The tire 2 is excellent in appearance quality. Further, by suppressing the flow, it is possible to suppress the label stuck to the raw cover for the purpose of lot management or the like from being covered with the topping rubber 62.

  In the tire 2, the inner end 52 of the side ply 18 is preferably located radially inside the point PA and located radially inside the tip 28 of the apex 26. In the tire 2, the concentration of strain on the inner end 52 can be suppressed. In the tire 2, occurrence of cracks starting from the inner end 52 can be suppressed. The tire 2 is excellent in durability.

  In the tire 2, the outer end 54 of the side ply 18 is positioned on the inner side in the axial direction than the end 42 of the belt 10. The outer end 54 is located closer to the equator plane than the end 42 of the belt 10. The side ply 18 overlaps the end 42 portion of the belt 10. The side ply 18 covers the end 42 of the belt 10. In the tire 2, the side ply 18 can restrain the movement of the end 42 of the belt 10. This tire 2 is excellent in durability and high-speed stability.

  In the tire 2, since the side ply 18 can restrain the end 42 of the belt 10, the band 12 can be removed from the constituent members of the tire 2. The removal of the band 12 can contribute to a reduction in tire mass. The reduction in mass can contribute to the fuel efficiency of the vehicle to which the tire 2 is attached.

  In FIG. 1, a double arrow line WA represents the width of the portion where the side ply 18 and the belt 10 overlap. The width WA is obtained by measuring the length from the outer end 54 of the side ply 18 to the end 42 of the belt 10. A double arrow line DA represents the distance between the chafer 16 and the side ply 18. The distance DA is obtained by measuring the distance from the outer end 48 of the chafer 16 to the inner end 52 of the side ply 18.

  In the tire 2, the width WA is preferably 15 mm or more and 50 mm or less. By setting the width WA to 15 mm or more, the side ply 18 can effectively restrain the movement of the end 42 of the belt 10. The tire 2 is excellent in durability and high-speed stability. In this respect, the width WA is more preferably 25 mm or more. By setting the width WA to 50 mm or less, the mass of the tire 2 can be appropriately maintained. The tire 2 does not hinder fuel efficiency. In this respect, the width WA is more preferably 40 mm or less.

  In the tire 2, it is preferable that the side ply 18 and the chafer 16 are close to each other from the viewpoint that a portion peculiar to the rigidity is not formed. From this viewpoint, the distance DA is preferably 5 mm or less. When the side ply 18 and the chafer 16 are overlaid, a portion having excessive rigidity is formed in the tire 2. In this respect, the distance DA is particularly preferably 0 mm. In the tire 2 in which the distance DA is appropriately controlled as described above, excellent steering stability can be maintained.

  In the tire 2, from the viewpoint of handling stability, the thickness of the side ply 18 is preferably 0.5 mm or more, and more preferably 1.0 mm or more. From the viewpoint of light weight, the thickness is preferably 2.0 mm or less.

  FIG. 3 is a plan view showing a part of the tire 2 of FIG. FIG. 3 shows a portion where the side ply 18 and the belt 10 overlap each other. In FIG. 3, the arrow line A represents the circumferential direction. In the tire 2, the belt cord 64 included in the outer layer 40 of the belt 10 is inclined with respect to the circumferential direction. In FIG. 3, the band 12 is interposed between the side ply 18 and the outer layer 40. As described above, the cord 66 of the band 12 extends substantially in the circumferential direction. As shown in the drawing, in the tire 2, the side cord 60 included in the side ply 18 preferably intersects the belt cord 64. This intersection can contribute to the restraint of the belt 10 by the side ply 18. The tire 2 is excellent in durability and high-speed stability.

  In FIG. 3, an arrow line B represents the longitudinal direction of the belt cord 64 included in the outer layer 40 of the belt 10. An arrow line C represents the longitudinal direction of the side cord 60 included in the side ply 18. The angle α is an intersection angle between the side cord 60 and the belt cord 64. This angle α is obtained by measuring the angle formed by the side cord 60 with respect to the belt cord 64. The lower limit value of the absolute value of the angle α is 0 °, and the upper limit value thereof is 90 °.

  In the tire 2, the absolute value of the angle α is preferably 45 ° or more from the viewpoint that the side ply 18 can effectively restrain the movement of the end 42 of the belt 10. Particularly preferably, this angle α is 90 °.

  In the tire 2, from the viewpoint of steering stability, the fineness of the side cord 60 is preferably 400 dtex or more, and more preferably 900 dtex or more. From the viewpoint that the rigidity of the tire 2 can be appropriately maintained, the fineness of the side cord 60 is preferably 2500 dtex or less.

  In the tire 2, from the viewpoint of handling stability, the density of the side cords 60 (number per 5 cm) is preferably 15 ends or more, and more preferably 20 ends or more. From the viewpoint that the rigidity of the tire 2 can be appropriately maintained, the density of the side cord 60 is preferably 70 ends or less.

  In the present invention, the size and angle of each member of the tire 2 and other tires to be described later are measured in a state where the tire 2 is incorporated in a regular rim and the tire 2 is filled with air so as to have a regular internal pressure. At the time of measurement, no load is applied to the tire 2. In the present specification, the normal rim means a rim defined in a standard on which the tire 2 depends. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In the present specification, the normal internal pressure means an internal pressure defined in a standard on which the tire 2 relies. “Maximum air pressure” in the JATMA standard, “maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in the TRA standard, and “INFLATION PRESSURE” in the ETRTO standard are normal internal pressures. In the case of the passenger car tire 2, the dimensions and angles are measured in a state where the internal pressure is 180 kPa.

  FIG. 4 is a cross-sectional view showing a part of a tire 68 according to another embodiment of the present invention. In FIG. 4, the side ply 70 is shown. The configuration of the tire 68 other than the side ply 70 is the same as that of the tire 2 shown in FIG.

  The side ply 70 includes a fabric 72 and a rubber 74 impregnated in the fabric 72. The fabric 72 is covered with rubber 74. The fabric 72 is composed of a large number of warps 76 and a large number of wefts 78. Examples of the woven structure of the woven fabric 72 include plain weave, twill weave and satin weave. The warp 76 and the weft 78 are made of organic fibers. The fabric 72 is made of organic fibers. Specific examples of the organic fiber include polyester fiber, polyethylene naphthalate fiber, nylon fiber, and aramid fiber. When the cord of the carcass 8 is nylon fiber, it is preferable that polyester fiber or polyethylene naphthalate fiber is used for the warp yarn 76 and the weft yarn 78 from the viewpoint of the rigidity of the tire 68.

  In the tire 68, the side ply 70 is reinforced with a fabric 72. The side ply 70 can contribute to the rigidity of the tire 68. The tire 68 having high rigidity can generate a large cornering force. The tire 68 is excellent in handling stability. In the tire 68, the side ply 70 includes a fiber and a rubber 74 that covers the fiber. The side ply 70 does not affect the mass of the tire 68. By using the side ply 70, the tire 68 having high rigidity can be obtained without increasing the mass.

  Although not shown, in the tire 68 as well, the side ply 70 covers the end portion of the belt, so that the movement of the end of the belt can be effectively restrained. The tire 68 is excellent in durability and high-speed stability.

  In the tire 68, from the viewpoint of handling stability, the fineness of the warp 76 and the weft 78 is preferably 400 dtex or more, and more preferably 900 dtex or more. From the viewpoint that the rigidity of the tire 68 can be properly maintained, the fineness of the warp 76 and the weft 78 is preferably 2500 dtex or less.

  In the tire 68, from the viewpoint of steering stability, the density of warps 76 and wefts 78 (number per 5 cm) is preferably 15 ends or more, and more preferably 20 ends or more. From the viewpoint that the rigidity of the tire 68 can be appropriately maintained, the density of the warp 76 and the weft 78 is preferably 70 ends or less.

  FIG. 5 is a cross-sectional view showing a part of a pneumatic tire 80 according to still another embodiment of the present invention. In FIG. 5, the vertical direction is the radial direction, the horizontal direction is the axial direction, and the direction perpendicular to the paper surface is the circumferential direction. The tire 80 has a substantially bilaterally symmetric shape with the one-dot chain line CL in FIG. 5 as the center. This alternate long and short dash line CL represents the equator plane of the tire 80. The equatorial plane CL extends in the circumferential direction. A point PA is a position indicating the maximum width of the tire 80. The tire 80 includes a tread 82, a bead 84, a carcass 86, a belt 88, a band 90, an inner liner 92, a wide ply 94, and a strip 96. The configuration of the tire 80 other than the wide ply 94 is the same as that of the tire 2 shown in FIG.

  The wide ply 94 is located outside the carcass 8. An end (outer end) 98 located on the radially outer side of the wide ply 94 is located in the vicinity of the end of the tread 82. The wide ply 94 extends along the carcass 86 inward in the radial direction from the outer end 98 to the vicinity of the bead 84. The wide ply 94 is folded back along the outer surface of the tire 80 from the outer side in the axial direction toward the inner side in the vicinity of the bead 84. In the tire 80, a portion of the wide ply 94 positioned in the vicinity of the bead 84 is the chafer 100, and a portion of the wide ply 94 from the vicinity of the bead 84 to the outer end 98 is the side ply 102. . In the tire 80, the chafer 100 and the side ply 102 are integrally formed. In the tire 80, the chafer 100 and the side ply 102 are continuously connected.

  Although not shown, in the tire 80, the wide ply 94 is made of a fabric and rubber impregnated in the fabric. This fabric consists of a number of warps and a number of wefts. The warp and weft are made of organic fibers. Preferred organic fibers include polyester fibers, polyethylene naphthalate fibers, nylon fibers, and aramid fibers. When the cord included in the carcass 86 is a nylon fiber, from the viewpoint of the rigidity of the tire 80, the organic fiber is preferably a polyester fiber or a polyethylene naphthalate fiber.

  When the tire 80 is incorporated into the rim, a portion corresponding to the chafer 100 of the wide ply 94 comes into contact with the rim. By this contact, the vicinity of the bead 84 is protected.

  In the tire 80, the outer end 98 of the wide ply 94 is located on the radially outer side of the band 90. The outer end 98 is located between the tread 82 and the belt 88. The wide ply 94 covers the end 104 portion of the belt 88.

  As described above, in the tire 80, the chafer 100 and the side ply 102 are integrally formed. In the tire 80, the number of parts constituting the tire 80 can be reduced. The tire 80 can contribute to an improvement in productivity.

  In the tire 80, the wide ply 94 is reinforced with a fabric. The wide ply 94 can contribute to the rigidity of the tire 80. The tire 80 having high rigidity can generate a large cornering force. The tire 80 is excellent in handling stability. In the tire 80, the wide ply 94 includes an organic fiber and rubber covering the organic fiber. By using this wide ply 94, a tire 80 having high rigidity can be obtained without increasing the mass.

  As described above, in the tire 80, the wide ply 94 covers the end 104 portion of the belt 88. Since the movement of the end 104 of the belt 88 can be effectively restrained, the tire 80 is excellent in durability and high-speed stability.

  The tire 80 is manufactured as follows. First, a wide ply 94 is formed by impregnating rubber into a woven fabric composed of a large number of warps and a large number of wefts. Next, the wide ply 94 is supplied to the former. Other members are also supplied to the former. Examples of the other members include an inner liner 92, a ply constituting the carcass 86, a bead 84, an inner layer and an outer layer constituting the belt 88, a tread 82, and the like. These rubber members are assembled in the former to obtain a raw cover. In this assembly, the wide ply 94 is folded back from the inside to the outside around the bead 84 and attached along the outer surface of the raw cover. By attaching the wide ply 94, the chafer 100 and the side ply 102 are formed. The process in which the raw cover is obtained in this way is called a molding process.

  Next, the raw cover is subjected to a vulcanization process. In the vulcanization process, this raw cover is first put into an opened mold. When thrown, the bladder is contracted. When thrown, the bladder is positioned inside the raw cover. Next, the bladder expands due to gas filling. Due to this expansion, the raw cover is deformed. This deformation is called shaping. Next, the mold is tightened. Next, the internal pressure of the bladder is increased. The raw cover is pressed between the cavity surface of the mold and the outer surface of the bladder. The raw cover is heated by heat conduction from the bladder and the mold. The rubber composition of the raw cover flows by pressurization and heating. The rubber composition causes a crosslinking reaction by heating, and the tire 80 is obtained.

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

[Example 1]
A pneumatic tire of Example 1 having the basic configuration shown in FIG. 1 and having the specifications shown in Table 2 below was obtained. The tire size is 215 / 45R17. The side ply includes a large number of side cords arranged in parallel. This side cord is a nylon fiber. The fineness of this side cord is 470 dtex / 2. The crossing angle α between the side cord and the belt cord included in the outer layer of the belt is 90 ° (degree). The inner end of the side ply is located radially inward from the position indicating the maximum tire width. The position of this inner end is represented as “G” in Table 2. The distance DA between the side ply and the chafer is 3 mm. The width WA of the portion where the side ply and the belt overlap is 30 mm. The side ply has a thickness of 2.0 mm.

[Comparative Example 3 and Examples 4 and 7 to 8]
Tires were obtained in the same manner as in Example 1 except that the distance DA was as shown in Tables 1 and 2 below. In Comparative Example 3, the chafer and the side ply overlap.

[Comparative Example 2 and Examples 2 to 3 and 9 to 10]
Tires were obtained in the same manner as in Example 1 except that the overlap width WA was as shown in Tables 1 and 2 below. In Comparative Example 2, the side ply and the belt do not overlap.

[Examples 5 to 6]
A tire was obtained in the same manner as in Example 1 except that the intersection angle α was as shown in Table 1 below.

[Comparative Example 4]
A tire was obtained in the same manner as in Example 1, except that the position of the inner end of the side ply and the position of the outer end of the chafer were arranged radially outside the position indicating the maximum tire width. The position of this inner end is represented as “B” in Table 2.

[Example 11]
A tire was obtained in the same manner as in Example 1 except that a side ply made of a woven fabric and a rubber impregnated in the woven fabric was used. This fabric is a plain fabric composed of a large number of warps and a large number of wefts. The warp and the weft are made of nylon fibers. The fineness of the warp and weft is 470 dtex / 2.

[Example 12]
A tire was obtained in the same manner as in Example 1 except that a chafer and a side ply were constituted by a wide ply made of a woven fabric and rubber impregnated in the woven fabric. In Example 13, the side ply and the chafer are continuously continuous. This fabric is a plain fabric composed of a large number of warps and a large number of wefts. The warp and the weft are made of nylon fibers. The fineness of the warp and weft is 470 dtex / 2.

[Comparative Example 1]
Comparative Example 1 is a commercially available conventional tire.

[Productivity evaluation]
The time required to produce one prototype tire was measured. Productivity was evaluated based on the reciprocal of this measurement time. The results are shown in Tables 1 and 2 below as index values with Comparative Example 1 taken as 100. It is shown that productivity is excellent, so that this value is large. In accordance with this evaluation, the tire mass was also measured. The measurement results are shown in Tables 1 and 2 below.

[Appearance evaluation]
The appearance of the prototype tire was visually observed to confirm the occurrence of rubber flow defects (bears). The results are shown in Tables 1 and 2 below as “G” when the occurrence of bears is small and “B” when the bears are large.

[Rigidity evaluation]
The lateral stiffness was evaluated by measuring the lateral spring characteristics of the prototype tire after mounting the prototype tire on a tire static test device. The size of the rim is 17 × 7JJ. The internal pressure of the tire was 180 kPa. The results are shown in Tables 1 and 2 below as index values with Comparative Example 1 as 100. The larger this value, the better.

[Durability evaluation]
The durability of the tire was evaluated by measuring the maximum speed at which the tire breaks in accordance with the high speed performance test of JIS D 4230 “Automobile Tire”. The tire internal pressure was 320 kPa, and the load was 2.4 kPa. This maximum speed was obtained as follows. First, (1) 10 minutes at 140 km / h, (2) 10 minutes at 150 km / h, (3) 10 minutes at 160 km / h, and (4) 10 minutes at 150 km / h in order of tire drums. The run was carried out. After each drum run, the tire was observed to check for damage. In the tire observation after running the drum in (4), the tire that was confirmed to be undamaged was subjected to 20 minutes of drum running while increasing the speed by 10 km / h. This drum running was continued until the tires were damaged. The speed at which the tire was damaged was the maximum speed at which the tire would break. The maximum speeds thus measured are shown in Tables 1 and 2 below. The larger this value, the better the durability.

  As shown in Tables 1 and 2, in the tires of the examples, the rigidity is increased without increasing the mass. The tire of this example is also excellent in durability. From this evaluation result, the superiority of the present invention is clear.

  The pneumatic radial tire according to the present invention can be mounted on various vehicles.

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 cross-sectional view showing a part of the side ply of the tire of FIG. FIG. 3 is a plan view showing a part of the tire of FIG. FIG. 4 is a cross-sectional view showing a part of a tire according to another embodiment of the present invention. FIG. 5 is a cross-sectional view showing a part of a pneumatic tire according to still another embodiment of the present invention.

Explanation of symbols

2, 68, 80 ... tire 4, 82 ... tread 6, 84 ... bead 8, 86 ... carcass 10, 88 ... belt 12, 90 ... band 14, 92 ... Inner liner 16, 100 ... Chafer 18, 70, 102 ... Side ply 20, 96 ... Strip 22 ... Tread surface 24 ... Core 26 ... Apex 30 ... Ply 32 ... Main part 34 ... Folded part 38 ... Inner layer 40 ... Outer layer 56 ... Buttress 60 ... Side cord 62 ... Topping rubber 64 ... Belt cord 66 ... Cord 72 ... Woven fabric 74 ... Rubber 76 ... Warp yarn 78 ... Weft yarn 94 ... Wide ply

Claims (5)

A tread whose outer surface forms a tread surface, a pair of beads, a carcass spanned between both beads, a belt positioned radially outward of the carcass, and the periphery of the bead from the inner side toward the outer side in the axial direction A pair of folded chafers and a pair of side plies located outside the carcass;
The bead includes a core and an apex extending radially outward from the core,
This side ply is located on the outside in the radial direction of the portion located on the outside in the axial direction of this chafer,
This side ply extends radially outward along this carcass,
The end located radially outward of this side ply is located between this tread and the belt,
The end located on the radially inner side of the side ply is located on the radially inner side of the position indicating the maximum width of the tire, and is located on the radially inner side of the tip of the apex,
A pneumatic radial tire in which the side ply includes fibers and rubber covering the fibers.   The tire according to claim 1, wherein the side ply is laminated on the carcass. The side ply includes a plurality of side cords made of the fibers and parallel to each other,
The belt is provided with a number of parallel belt cords,
The tire according to claim 1 or 2, wherein an absolute value of an intersection angle between the side cord and the belt cord is 45 ° or more and 90 ° or less.   The tire according to claim 1 or 2, wherein the side ply includes a woven fabric in which the fibers are woven and a rubber impregnated in the woven fabric. A tread whose outer surface forms a tread surface, a pair of beads, a carcass spanned between both beads, a belt positioned radially outward of the carcass, and the periphery of the bead from the inner side toward the outer side in the axial direction A pair of folded chafers and a pair of side plies located outside the carcass;
This side ply is located on the outside in the radial direction of the portion located on the outside in the axial direction of this chafer,
This side ply extends radially outward along this carcass,
The end located radially outward of this side ply is located between this tread and the belt,
This side ply and this chafer are integrally formed,
A pneumatic radial tire in which the side ply and the chafer are made of a fabric in which fibers are woven and a rubber impregnated in the fabric.

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