JP2015039970A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of reducing weight of the tire.SOLUTION: A pneumatic tire 1 comprises: a bead core 51; a bead filler 52 that is arranged outside in a tire radial direction of the bead core 51; carcass layers 61-63 that are formed of thermoplastic sheets and enclose the bead core 51 and the bead filler 52 respectively by winding up the end portion thereof outside in a tire width direction; a side wall rubber 41 that is arranged outside in the tire width direction of the winding-up portions of the carcass layers 61-63; and an enforcing layer 9 that is arranged between the bead filler 52 and the side wall rubber 41 and covers a lateral surface outside in the tire width direction of the bead filler 52.

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of reducing the tire weight.

  In recent years, there is a demand to reduce the weight of tires in consideration of the environment such as global warming countermeasures. In this regard, a conventional pneumatic tire employs a configuration in which a tire member having a large volume (for example, cap tread rubber, sidewall rubber, etc.) is thinned. However, when the tire member is thinned, the wear resistance performance and durability performance of the tire are lowered. For this reason, there is a problem that it is difficult to further reduce the weight of the tire.

  As conventional pneumatic tires related to such problems, techniques described in Patent Documents 1 and 2 are known.

JP 2011-042233 A JP 2011-042234 A

  An object of the present invention is to provide a pneumatic tire capable of reducing the tire weight.

  In order to achieve the above object, a pneumatic tire according to the present invention includes a bead core, a bead filler disposed on the outer side of the bead core in the tire radial direction, and a thermoplastic sheet, and an end portion is wound up outward in the tire width direction. A carcass layer that wraps around each of the bead core and the bead filler, a side wall rubber that is disposed on the outer side in the tire width direction of the rolled-up portion of the carcass layer, and the bead filler that is disposed between the bead filler and the side wall rubber And a reinforcing layer covering a side surface on the outer side in the tire width direction.

  The pneumatic tire according to the present invention has the following advantages: (1) Since the carcass layer is made of a thermoplastic sheet, the weight of the tire is reduced as compared with a structure in which the carcass layer is formed by coating steel or organic fiber material with coated rubber. There is. In addition, in the (2) tire vulcanization step, the reinforcing layer functions as a backing material for the bead filler and suppresses excessive flow of the bead filler. Thereby, there is an advantage that the deformation of the carcass layer made of the thermoplastic sheet is suppressed and the buckle of the carcass layer is suppressed.

FIG. 1 is a meridional sectional view of a pneumatic tire according to this embodiment. FIG. 2 is a partially enlarged meridional sectional view showing a carcass layer of the pneumatic tire according to the present embodiment. FIG. 3 is an explanatory view showing a method for manufacturing a pneumatic tire according to the present embodiment. FIG. 4 is an explanatory view showing a method for manufacturing a pneumatic tire according to the present embodiment. FIG. 5 is an explanatory diagram showing a method for manufacturing a pneumatic tire according to the present embodiment. FIG. 6 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment. FIG. 7 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment. FIG. 8 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment. FIG. 9 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment. FIG. 10 is an explanatory diagram showing a modification of the pneumatic tire according to the present embodiment. FIG. 11 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment. FIG. 12 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment. FIG. 13 is a chart showing the results of the performance test of the pneumatic tire according to the present embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Pneumatic tire]
FIG. 1 is a meridional sectional view of a pneumatic tire 1 according to this embodiment. In the following description, the tire radial direction refers to a direction orthogonal to the rotation axis (not shown) of the pneumatic tire 1, and the tire radial direction inner side refers to the side toward the rotation axis in the tire radial direction, the tire radial direction outer side. Means the side away from the rotation axis in the tire radial direction. Further, the tire circumferential direction refers to a direction around the rotation axis as a central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction means the side toward the tire equator plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction means the tire width direction. Is the side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is orthogonal to the rotation axis of the pneumatic tire 1 and passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line is a line along the tire circumferential direction of the pneumatic tire 1 on the tire equator plane CL. In the present embodiment, the same sign “CL” as that of the tire equator plane is attached to the tire equator line.

  As shown in FIG. 1, the pneumatic tire 1 according to the present embodiment includes a tread portion 2, shoulder portions 3 on both sides thereof, and a sidewall portion 4 and a bead portion 5 that are sequentially continuous from the shoulder portions 3. Yes. The pneumatic tire 1 includes a carcass layer 6, a belt layer 7, and a belt reinforcing layer 8.

  The tread portion 2 is made of a rubber material (tread rubber), is exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the surface thereof is the contour of the pneumatic tire 1. A tread surface 21 is formed on the outer peripheral surface of the tread portion 2, that is, on the tread surface that contacts the road surface during traveling. The tread surface 21 is provided with a plurality of (four in this embodiment) main grooves 22 extending along the tire circumferential direction. The tread surface 21 is formed with a plurality of rib-like land portions 23 extending along the tire circumferential direction by the plurality of main grooves 22. Although not shown in the figure, the tread surface 21 is provided with a lug groove that intersects the main groove 22 in each land portion 23. The land portion 23 is divided into a plurality of portions in the tire circumferential direction by lug grooves. Further, the lug groove is formed to open to the outer side in the tire width direction on the outermost side in the tire width direction of the tread portion 2. Note that the lug groove may have either a form communicating with the main groove 22 or a form not communicating with the main groove 22.

  The shoulder portion 3 is a portion on both outer sides in the tire width direction of the tread portion 2. Further, the sidewall portion 4 is exposed at the outermost side in the tire width direction of the pneumatic tire 1. The bead unit 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 52 is a rubber material disposed in a space formed by winding up the end portion in the tire width direction of the carcass layer 6 at the position of the bead core 51.

  The carcass layer 6 has both ends in the tire width direction wound around a pair of bead cores 51 from the inner side in the tire width direction to the outer side in the tire width direction and extended outward in the tire radial direction. It constitutes the skeleton of the tire. Details of the carcass layer 6 will be described later.

  The belt layer 7 has a multilayer structure in which at least two belt plies 71 and 72 are laminated. The belt layer 7 is disposed on the outer side in the tire radial direction which is the outer periphery of the carcass layer 6 in the tread portion 2 and covers the carcass layer 6 in the tire circumferential direction. Is. In the belt plies 71 and 72, a plurality of cords (not shown) arranged in parallel at a predetermined angle (for example, 20 degrees to 30 degrees) with respect to the tire circumferential direction are covered with coat rubber. The cord is made of steel or organic fiber (polyester, rayon, nylon, etc.). Further, the overlapping belt plies 71 and 72 are arranged so that the cords intersect each other.

  The belt reinforcing layer 8 is disposed on the outer side in the tire radial direction which is the outer periphery of the belt layer 7 and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 is formed by coating a plurality of cords (not shown) arranged substantially parallel (± 5 degrees) in the tire circumferential direction and in the tire width direction with a coat rubber. The cord is made of steel or organic fiber (polyester, rayon, nylon, etc.). The belt reinforcing layer 8 shown in FIG. 1 includes a belt reinforcing layer 81 disposed so as to cover the entire belt layer 7 on the outer side in the tire radial direction of the belt layer 7, and the belt layer 7 on the outer side in the tire radial direction of the belt reinforcing layer 81. The belt reinforcing layer 82 is arranged so as to cover the whole, and the belt reinforcing layer 83 is arranged so as to cover each end in the tire width direction of the belt layer 7 outside the belt reinforcing layer 82 in the tire width direction. Has been. The configuration of the belt reinforcing layer 8 is not limited to the above, and is not clearly shown in the figure, but is configured to cover the entire belt layer 7 or to cover each end of the belt layer 7 in the tire width direction. There are only configurations arranged in the above, or a combination of these as appropriate. That is, the belt reinforcing layer 8 overlaps at least both ends of the belt layer 7 in the tire width direction. The belt reinforcing layer 8 is provided by winding a strip-shaped strip material (for example, a width of 10 [mm]) in the tire circumferential direction.

[Carcass layer]
FIG. 2 is a partially enlarged meridional sectional view showing a carcass layer of the pneumatic tire according to the present embodiment.

  In the pneumatic tire 1 described above, the carcass layer 6 is composed of at least two layers (indicated by two layers in FIG. 1 and indicated by three layers in FIG. 2), and is composed of thermoplastic sheets (61, 62, 63). Is formed. And as for the thermoplastic sheet (61, 62, 63), the rubber layer 6a is arrange | positioned while each layer overlaps. In FIG. 2, the rubber layer 6 a is also provided outside the thermoplastic sheet 61 which is the outermost part in the rolled-up portion of the bead portion 5, except during the overlapping of the layers of the thermoplastic sheets (61, 62, 63). The form is shown.

  The thermoplastic sheet (61, 62, 63) is composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer component in a thermoplastic resin, and has no cord.

  As the thermoplastic resin used in the present embodiment, for example, polyamide resin [for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 (N11), nylon 12 (N12), Nylon 610 (N610), Nylon 612 (N612), Nylon 6/66 copolymer (N6 / 66), Nylon 6/66/610 copolymer (N6 / 66/610), Nylon MXD6, Nylon 6T, Nylon 9T , Nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer], polyester resin [for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI) , Polybutylene terephthalate / tetramethylene glycol Copolymer, PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, aromatic polyester such as polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer], polynitrile series Resins [eg, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer], poly (meth) acrylate Resin (for example, polymethyl methacrylate (PMMA), polyethyl methacrylate, ethylene ethyl acrylate copolymer (EEA), ethylene acrylic acid copolymer (EAA), ethylene methyl acrylate resin (EMA)), polyvinyl Fat [for example, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, chloride Vinylidene / methyl acrylate copolymer], cellulose resin [eg, cellulose acetate, cellulose acetate butyrate], fluorine resin [eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetra Fluoroethylene / ethylene copolymer (ETFE)], imide resin [for example, aromatic polyimide (PI)] and the like.

  Examples of the elastomer used in this embodiment include diene rubbers and hydrogenated products thereof [eg, NR, IR, epoxidized natural rubber, SBR, BR (high cis BR and low cis BR), NBR, hydrogenated NBR] , Hydrogenated SBR], olefin rubber [eg ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber (M-EPM)], butyl rubber (IIR), isobutylene and aromatic vinyl or diene monomer copolymer , Acrylic rubber (ACM), ionomer, halogen-containing rubber [for example, brominated product of Br-IIR, Cl-IIR, isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHC, CHR) , Chlorosulfonated polyethylene (CSM), chlorine Polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)], silicone rubber [eg methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber], sulfur-containing rubber [eg polysulfide rubber], fluoro rubber [eg Vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber, fluorine-containing phosphazene rubber), thermoplastic elastomer (for example, styrene elastomer, olefin elastomer, polyester elastomer, Urethane elastomer, polyamide elastomer] and the like.

  As described above, in the pneumatic tire 1 of the present embodiment, at least two carcass layers 6 extend to the bead core 51 in which both end portions in the tire width direction are arranged in the bead portions 5 and the tire width of the bead core 51 is increased. In the pneumatic tire 1 wound up from the inner side in the tire width direction outer side and extended outward in the tire radial direction, the carcass layer 6 is formed of a thermoplastic sheet (61, 62, 63), and is at least thermoplastic. The rubber layer 6a is disposed between the layers of the sheets (61, 62, 63).

  According to this pneumatic tire 1, the carcass layer 6 is formed of a thermoplastic sheet (61, 62, 63), and the rubber layer 6 a is disposed at least between each layer, thereby being applied to a general pneumatic tire. Such a carcass cord arranged in the tire width direction has a function of becoming a tire skeleton in the same manner as a carcass layer covered with a coat rubber. This thermoplastic sheet (61, 62, 63) is lighter than the carcass cord. As a result, the tire weight can be further reduced.

  Moreover, according to the pneumatic tire 1, the carcass layer 6 is formed of the thermoplastic sheet (61, 62, 63), thereby suppressing air leakage in the inner liner applied to the inside of a general pneumatic tire. It has the function to do. As a result, the inner liner can be omitted and the tire weight can be further reduced.

  Furthermore, according to this pneumatic tire 1, since the carcass layer 6 is formed of the thermoplastic sheet (61, 62, 63), in the carcass layer 6, a calendar process (rubber sheeting (sheet processing), woven fabric) The step of performing a rubber coating (topping process) operation or the like can be omitted, so that the tire manufacturing process can be simplified.

  The average thickness of the rubber layer 6a is preferably 0.05 [mm] or more and 0.5 [mm] or less. If it is 0.05 [mm] or more, manufacture is possible, and if it is 0.5 [mm] or less, an increase in weight can be prevented.

In the pneumatic tire 1 of the present embodiment, the thermoplastic sheet (61, 62, 63) forming the carcass layer 6 has a single layer average thickness of 0.03 [mm] or more and 1.00 [mm] or less. And an air permeability coefficient of 3 × 10 ^ 12 [cc · cm / cm ² · sec · cmHg] or more and 500 × 10 ^ 12 [cc · cm / cm ² · sec · cmHg] or less is preferable.

Here, the average thickness is determined by cutting the tire to be measured in the tire circumferential direction with a width of 20 [mm] to 30 [mm] in the tire circumferential direction, and dividing the length in the tire width direction into at least eight equal parts. The thickness of each of the thermoplastic sheets (61, 62, 63) constituting the material is measured and averaged for a single layer. The air permeability coefficient is JIS K7126 “Plastic film and sheet gas permeability test method (A)”, the test gas is air (N ₂ : O ₂ = 8: 2), and the test temperature is 30 ° C. ].

  According to this pneumatic tire 1, the thermoplastic sheet (61, 62, 63) has a remarkable function as a tire skeleton by defining the thickness, and the inner liner function by defining the air permeability coefficient. Therefore, the effect of reducing the tire weight can be remarkably obtained. The average thickness of the single layer of the thermoplastic sheets (61, 62, 63) is 0.05 [mm] or more and 0.002 mm in order to obtain the effect of reducing the tire weight while also serving as the inner liner. More preferably, the average thickness of the single layer of the thermoplastic sheet (61, 62, 63) is more preferably 6 [mm] or less, in order to obtain a more remarkable effect of reducing the tire weight while also serving as an inner liner. More preferably, the thickness is 0.08 [mm] or more and 0.5 [mm] or less.

  In the pneumatic tire 1 of the present embodiment, the rubber layer 6a has a peel strength of 50 [N / 25 mm] or more and 400 [N / 25 mm] or less from the thermoplastic sheet (61, 62, 63). preferable.

  Here, the peel strength is obtained according to JIS K6256.

  According to the pneumatic tire 1, the adhesion between the carcass layers 6 is improved by the regulation of the peel strength of the rubber layer 6a, and as a result, the durability of the tire can be improved. The upper limit of the peel strength may exceed 400 [N / 25 mm], but it tends to be in close contact with the metal drum of the supply device at the time of tire molding, resulting in a decrease in handling properties and difficulty in correction. 25 mm]. In order to obtain the effect of improving the durability remarkably, the peel strength of the rubber layer 6a is more preferably 75 [N / 25 mm] or more and 400 [N / 25 mm] or less, and the durability is further improved and the tire is molded. In order to remarkably obtain the effect of further improving the handleability at the time, it is more preferable that the peel strength of the rubber layer 6a is 100 [N / 25 mm] or more and 300 [N / 25 mm] or less.

Further, in the pneumatic tire 1 of the present embodiment, the rubber layer 6a has R ¹ , R ² , R ³ , R ⁴ and R ⁵ in the following formula (1), each having hydrogen, a hydroxyl group or a carbon atom number of 1. A rubber composition containing a condensate of formaldehyde and 8 or less alkyl groups and formaldehyde, a methylene donor, and a vulcanizing agent, the blending amount of the condensate being 100 parts by mass of the rubber component The blending amount of methylene donor is 0.5 to 80 parts by weight with respect to 100 parts by weight of the rubber component, and the blending amount of methylene donor / condensation is 0.5 to 20 parts by weight. It is preferable that the ratio of the amount of the product is 1 or more and 4 or less.

  According to this pneumatic tire 1, it becomes possible to improve the adhesiveness of the rubber layer 6a to the thermoplastic sheets (61, 62, 63). That is, the peel strength of the rubber layer 6a with respect to the thermoplastic sheet (61, 62, 63) is improved, the adhesion between the carcass layers 6 is improved, and as a result, the durability as a tire can be improved.

  Moreover, in the pneumatic tire 1 of this embodiment, it is preferable that the thermoplastic sheet (61, 62, 63) has a single layer tensile yield strength at room temperature of 1 [MPa] to 100 [MPa].

  Here, the tensile yield strength is obtained by measuring by a test method specified in JIS K7113.

  According to this pneumatic tire 1, plastic deformation when the thermoplastic sheet (61, 62, 63) is pulled is suppressed by the regulation of the tensile yield strength of the thermoplastic sheet (61, 62, 63). It becomes possible to improve pressure resistance. By improving the pressure resistance, it is possible to reduce the number of laminated thermoplastic sheets (61, 62, 63) and improve the weight reduction of the tire. The upper limit of tensile yield strength may exceed 100 [MPa], but the shape tends to become non-uniform in the expansion of the thermoplastic sheet (61, 62, 63) during inflation molding. For ease of manufacturing, the pressure was set to 100 [MPa]. The tensile yield strength of the thermoplastic sheet (61, 62, 63) is set to 2 in order to significantly reduce the number of laminated thermoplastic sheets (61, 62, 63) and to obtain the effect of facilitating production. More preferably, the pressure is set to [MPa] or more and 80 [MPa] or less.

  Moreover, in the pneumatic tire 1 of this embodiment, it is preferable that the thermoplastic sheet (61, 62, 63) has a single-layer elongation at break of 80 [%] to 500 [%] at room temperature.

  According to this pneumatic tire 1, for example, even if local distortion occurs in the tire due to a tool or the like during rim assembly work, the thermoplastic sheet (61, 62, 63) can be prevented from being broken. It is possible to use a mount (rim assembly) device. Moreover, the tire durability at the time of actual use is also improved by ensuring the breaking elongation. In addition, although the upper limit of breaking elongation may exceed 500 [%], it was prescribed | regulated as a realizable range. In addition, in order to obtain the effect which ensures the durability of a thermoplastic sheet (61, 62, 63) notably, elongation at break of a thermoplastic sheet (61, 62, 63) is 100 [%] or more and 500 [%] or less. More preferably.

  In the configuration of FIG. 2, as described above, the laminate 60 has three carcass layers 61 to 63 made of a thermoplastic sheet. The rubber layer 6a is sandwiched between the adjacent carcass layers 61, 62; 62, 63. Thereby, the rubber layer 6a functions as a cover material, and mutual contact between the adjacent carcass layers 61, 62; 62, 63 is prevented.

  In the configuration of FIG. 2, the laminate 60 has a pair of rubber layers 6a and 6a in the innermost layer and the outermost layer. Thereby, the rubber layers 6a and 6a function as a cover material at the rewinding portion of the laminate 60, and the carcass layers 61 and 63 and the peripheral members (for example, the side wall rubber 41 and the bead portion constituting the side wall portion 4). 5 are prevented from contacting each other with the bead core 51, the bead filler 52, the rim cushion rubber 53, etc.).

  Further, the rubber layer 6a located on the innermost peripheral side functions as a cover material at the turn-up portion of the laminated body 60, and self-contact between the main body portion and the winding portion of the carcass layer 63 is prevented.

  Further, the rubber layer 6a located on the innermost circumferential side with respect to the tire lumen portion covers the inner circumferential surface of the laminate 60 and functions as an inner liner. Further, the carcass layers 61 to 63 themselves function as an inner liner by being made of a thermoplastic film having low gas permeability.

  1 and 2, the pneumatic tire 1 includes at least two carcass layers 6 (61, 62; 61-63) as described above. However, the present invention is not limited to this, and the pneumatic tire 1 may include a single-layer carcass layer 6 (not shown). At this time, it is preferable that the laminated body 60 includes a pair of rubber layers 6 a and 6 a that sandwich the carcass layer 6, as in the configuration of FIG. 2.

[Reinforcement layer as backing material]
In recent years, there is a demand to reduce the weight of tires in consideration of the environment such as global warming countermeasures. In this regard, a conventional pneumatic tire employs a configuration in which a tire member having a large volume (for example, cap tread rubber, sidewall rubber, etc.) is thinned. However, when the tire member is thinned, the wear resistance performance and durability performance of the tire are lowered. For this reason, there is a problem that it is difficult to further reduce the weight of the tire.

  For this reason, in this pneumatic tire 1, as described above, the weight of the tire is reduced by using a carcass layer made of a thermoplastic sheet.

  By the way, in a general carcass layer, for example, a carcass layer formed by rolling a plurality of carcass cords made of steel or organic fiber material with a coating rubber, the carcass layer is beaded during the vulcanization process of the tire. It has the effect | action which hold | maintains the shape of a part. For this reason, when peripheral rubbers, such as a bead filler, are heated and pressurized in a vulcanization process, it is hard to produce the molding defect resulting from a flow of peripheral rubber.

  However, in the carcass layer made of the thermoplastic sheet as described above, the carcass layer itself is softened by heating during the vulcanization process. Then, when the peripheral rubber softens and flows due to heating and pressurization, there is a new problem that the carcass layer is deformed to cause molding defects such as a buckle.

  Therefore, in this pneumatic tire, the following configuration is employed in order to suppress molding defects of the carcass layer due to rubber flow (flow of peripheral rubber) during the vulcanization process.

  As shown in FIG. 2, the pneumatic tire 1 includes a reinforcing layer 9. The reinforcing layer 9 is disposed between the bead filler 52 and the sidewall rubber 41 and covers the side surface of the bead filler 52 on the outer side in the tire width direction. Therefore, the reinforcing layer 9 is embedded in a region between the bead filler 52 and the sidewall rubber 41 and reinforces this region.

  The side surface on the outer side in the tire width direction of the bead filler 52 refers to a wall surface in a region from the end portion on the outer side in the tire radial direction of the bead core 51 to the end portion on the outer side in the tire radial direction of the bead filler 52.

  Further, the reinforcing layer 9 needs to cover at least 50 [%] of the side surface of the bead filler 52 on the outer side in the tire width direction in a cross-sectional view in the tire meridian direction (see FIG. 2), and 80 [%] It is preferable to cover the above region. The reinforcing layer 9 is preferably disposed so as to cover the top portion of the bead filler 52 on the outer side in the tire radial direction. In the product tire, as shown in FIG. 2, the reinforcing layer 9 extends in the tire radial direction along the bead filler 52.

  Moreover, it is preferable that the distance D between the end portion of the reinforcing layer 9 and the end portion of the bead filler 52 on the outer side in the tire radial direction is in a range of 5 [mm] ≦ D in a cross-sectional view in the tire meridian direction. Therefore, the end portion of the reinforcing layer 9 and the end portion of the bead filler 52 are arranged so as to be displaced from each other.

  The upper limit of the distance D when the reinforcing layer 9 extends beyond the radially outer end of the bead filler 52 is preferably D ≦ 15 [mm]. Thereby, the effect | action of the reinforcement layer 9 mentioned later is ensured appropriately. On the other hand, if the distance D is too large, the rolling resistance of the tire deteriorates, which is not preferable.

  The distance D is measured at the stage of the tire product after the vulcanization process.

  Further, the reinforcing layer 9 has physical properties and a structure capable of appropriately maintaining the shape in the tire vulcanization process. Thereby, the function of the reinforcement layer 9 mentioned later is securable.

  For example, the reinforcing layer 9 is preferably made of a composite material including a fiber material. Specifically, the reinforcing layer 9 is (a) a structure formed by rolling a plurality of cord materials coated with coat rubber, (b) a structure formed by plain weaving a plurality of cord materials coated with coat rubber, c) The structure which mixes a short fiber material in a rubber material, etc. are mentioned. As the cord materials (a) and (b), for example, organic fibers such as polyester, nylon, and aramid, steel cords, and the like can be used, and the cord material may be formed of a monofilament or a stranded wire. Moreover, as a short fiber material of said (c), glass fiber etc. can be employ | adopted, for example.

  In the configuration (a), the number of ends of the cord material is preferably in the range of 15 [lines / 50 mm] to 50 [lines / 50 mm], and is preferably 30 [lines / 50 mm] to 50 [lines / 50 mm]. 50 mm] or less is preferable. The inclination angle θ (0 [deg] to 90 [deg]) of the cord material of the reinforcing layer 9 is preferably in the range of 10 [deg] ≦ θ ≦ 90 [deg], and 65 [deg] ≦ θ. More preferably, it is in the range of ≦ 90 [deg], and more preferably in the range of 75 [deg] ≦ θ ≦ 90 [deg]. The inclination angle θ is measured as an angle formed by the longitudinal direction of the arranged cord members and the tire circumferential direction. The function of the reinforcing layer 9 to be described later can be secured by the number of ends and the inclination angle θ.

  Further, for example, the reinforcing layer 9 may be made of a single rubber material. In such a configuration, the minimum torque measured with a rheometer is within a range of 0.35 [N · m] or more under the measurement condition of the rubber material constituting the reinforcing layer 9 at a temperature of 170 [° C.] The shape of the reinforcing layer 9 during the vulcanization process is appropriately ensured.

  For example, in the configuration of FIG. 2, three carcass layers 61 to 63 made of a thermoplastic sheet and four rubber layers 6a sandwiching these carcass layers 61 to 63 are alternately stacked (disposed). (See FIG. 4 described later). Thereby, both surfaces of the laminate 60 are sandwiched between the pair of rubber layers 6a and 6a, and the surfaces of the innermost and outermost carcass layers 61 and 63 are covered. Moreover, the laminated body 60 is wound up and arranged on the outer side in the tire width direction so as to wrap the bead core 51 and the bead filler 52.

  Further, the reinforcing layer 9 is an annular and sheet-like member formed by rolling a plurality of cord materials coated with coat rubber, and is disposed along the bead filler 52 over the entire circumference in the tire circumferential direction. . In addition, the reinforcing layer 9 is disposed between the bead core 51 and the bead filler 52 and the laminate 60. Further, the reinforcing layer 9 extends from the bead core 51 to a position beyond the outer end of the bead filler 52 in the tire radial direction. For this reason, the reinforcing layer 9 is disposed so as to cover the entire region of the outer side surface of the bead filler 52 in the tire width direction and is adjacent to the bead filler 52. Further, the end portion of the reinforcing layer 9 on the inner side in the tire radial direction is sandwiched between the side surface of the bead core 51 and the laminate 60 and is adjacent thereto. Further, the end portion of the reinforcing layer 9 on the outer side in the tire radial direction is disposed so as to be sandwiched between the main body portion and the winding portion of the laminate 60. Further, the end portion of the reinforcing layer 9 and the end portion of the bead filler 52 are arranged so as to be shifted from each other in the tire radial direction. Further, since the laminated body 60 has the rubber layer 6a as the innermost layer, the rubber layer 6a functions as a cover material at the adjacent portion between the reinforcing layer 9 and the laminated body 60, and the reinforcing layer 9 and the carcass layer 63 Mutual contact is prevented.

[Tire manufacturing method]
3-5 is explanatory drawing which shows the manufacturing method of the pneumatic tire which concerns on this embodiment. These drawings schematically show the winding process of the carcass layer in the green tire molding process.

  In the manufacturing process of the pneumatic tire 1, various tire members are put on a molding machine to form a green tire (not shown).

  Specifically, as shown in FIG. 3, the assembly of the bead core 51 and the bead filler 52, the laminate 60 of the thermoplastic sheets 61 to 63 and the rubber layer 6a, the side wall rubber 41 and the rim cushion rubber 53 are integrated. The formed rubber member and the reinforcing layer 9 are disposed on a molding drum (not shown) and positioned relative to each other. At this time, the reinforcing layer 9 is disposed so as to cover the side surface of the bead filler 52 on the outer side in the width direction in advance. Further, as shown in FIG. 3, the reinforcing layer 9 is preferably disposed so as to cover the top of the bead filler 52 on the outer side in the radial direction by extending to the outer side in the tire radial direction than the bead filler 52.

  Moreover, as shown in FIG. 4, the thermoplastic sheets 61-63 and the rubber layer 6a are laminated | stacked alternately previously beforehand, and the laminated body 60 is shape | molded. The laminated body 60 or the carcass layers 61 to 63 constituting the laminated body 60 may be a belt-like member or a seamless cylindrical member (not shown) at the time of green tire molding.

  Next, as shown in FIG. 5, a turn-up bladder (not shown) is used so that the laminated body 60, the sidewall rubber 41 and the rim cushion rubber 53 wrap around the assembly of the bead core 51 and the bead filler 52. It is wound up in the width direction outside.

  Next, the above-mentioned member is pressure-bonded by a turn-up bladder to form an annular member having a uniform cross section in the circumferential direction. Next, belt plies 71 and 72, belt reinforcing layers 81 to 83, tread rubber, and the like constituting the belt layer 7 are arranged on the outer periphery of the annular member, and a green tire is molded.

  Next, this green tire is filled in a tire vulcanization mold (not shown). And this vulcanization mold is heated and vulcanization of a green tire is performed. At this time, the reinforcing layer 9 functions as a backing material of the bead filler 52 and suppresses excessive flow of the bead filler 52 softened by heating. Thereby, the deformation | transformation of the carcass layers 61-63 which consist of a thermoplastic sheet is suppressed, and the buckle of the carcass layers 61-63 is suppressed.

  Thereafter, the vulcanized tire is pulled out from the tire vulcanization mold and taken out.

[Modification]
6-11 is explanatory drawing which shows the modification of the pneumatic tire which concerns on this embodiment. These drawings schematically show the arrangement of the reinforcing layer 9.

  In the configuration of FIG. 2, as shown in FIG. 5, the reinforcing layer 9 is disposed so as to be sandwiched between the bead core 51 and the bead filler 52 and the laminate 60, and the tire radial direction from the bead core 51 to the bead filler 52 It extends to a position beyond the outer edge. For this reason, the reinforcement layer 9 is arrange | positioned adjacent to the bead filler 52, and the whole area | region of the side surface of the bead filler 52 outside the tire width direction is arrange | positioned.

  In the configuration of FIG. 5, the reinforcing layer 9 is located between the bead filler 52 and the laminated body 60 and covers the side surface of the bead filler 52, so that excessive flow of the bead filler 52 during the tire vulcanization process is prevented. It is effectively suppressed, and the influence on the carcass layers 61 to 63 due to the excessive flow of the bead filler 52 is reduced. This is preferable in that the deformation of the carcass layers 61 to 63 can be effectively suppressed. In addition, such a configuration is preferable in that the green tire molding process can be facilitated because the reinforcing layer 9 can be disposed in advance in the bead filler 52 in the green tire molding process, as shown in FIG.

  However, the present invention is not limited to this, and as shown in FIG. 6, the reinforcing layer 9 may be disposed so as to be sandwiched between the plurality of carcass layers 61, 62; Even with this configuration, it is possible to suppress the deformation of the carcass layers 61 to 63 by suppressing the excessive flow of the bead filler 52 during the tire vulcanization molding. In the configuration of FIG. 6, the reinforcing layer 9, the carcass layers 61 to 63, and the rubber layer 6a are laminated in advance in the green tire molding process, and a laminate 60 including the reinforcing layer 9 is molded (illustration shown). (Omitted). And the reinforcement layer 9 is wound up with the laminated body 60 (refer FIG. 6), and a green tire is shape | molded.

  Further, as shown in FIG. 7, the reinforcing layer 9 may be disposed so as to be sandwiched between the laminate 60, the sidewall rubber 41, and the rim cushion rubber 53. Even with this configuration, it is possible to suppress the deformation of the carcass layers 61 to 63 by suppressing the excessive flow of the bead filler 52 during the tire vulcanization process. In the configuration of FIG. 7, the reinforcing layer 9 is sandwiched and set between the laminate 60, the sidewall rubber 41, and the rim cushion rubber 53 in the green tire molding process (not shown in FIG. 3). reference.). And the reinforcement layer 9 is rolled up with the laminated body 60, the side wall rubber 41, and the rim cushion rubber 53 (refer FIG. 7), and a green tire is shape | molded.

  6 and 7, the rubber layer 6a is disposed between the reinforcing layer 9 and the carcass layers 61; 62; 63 adjacent to the reinforcing layer 9, as in the configuration of FIG. Is preferred. For example, in the configuration of FIG. 6, the rubber layers 6 a and 6 a are disposed between the reinforcing layer 9 and the pair of carcass layers 61 and 62; 62 and 63 sandwiching the reinforcing layer 9. In the configuration of FIG. 7, the rubber layer 6 a is disposed between the reinforcing layer 9 and the carcass layer 63 that is the outermost layer of the stacked body 60. Thereby, the rubber layer 6a functions as a cover material, and mutual contact between the reinforcing layer 9 and the carcass layers 61 and 63 is prevented.

  In the configuration of FIG. 2, as shown in FIG. 3, the reinforcing layer 9 extends from the bead core 51 to a position beyond the end of the bead filler 52 in the tire radial direction. For this reason, the reinforcing layer 9 is disposed so as to cover the entire side surface of the bead filler 52 on the outer side in the tire width direction, and is disposed so as to cover the top portion on the radially outer side of the bead filler 52. Such a configuration is preferable in that the excessive flow of the bead filler 52 during the tire vulcanization step can be suppressed and deformation of the carcass layers 61 to 63 can be suppressed.

  However, not limited to this, as shown in FIG. 8, the reinforcing layer 9 may be disposed so as to cover only a partial region of the side surface of the bead filler 52 on the outer side in the tire width direction. At this time, as described above, the reinforcing layer 9 needs to cover at least 50% of the side surface region (the length L1 region) of the bead filler 52. Further, the reinforcing layer 9 may be disposed in a region on the inner side in the tire radial direction from the end portion on the outer side in the tire radial direction of the bead filler 52 (not shown).

  Further, as shown in FIG. 9, it is preferable that the reinforcing layer 9 extends to the inside of the bead core 51 in the tire radial direction. At this time, it is preferable that the radially inner end of the reinforcing layer 9 extends from the center of gravity of the bead core 51 to the inner side in the tire width direction than the perpendicular line that extends down to the tire rotation axis (not shown). Thereby, durability of the edge part of the reinforcement layer 9 is ensured.

  Further, as shown in FIG. 10, the reinforcing layer 9 may be wound up so as to wrap the bead core 51 and extend to the inner side surface of the bead filler 52 in the tire width direction. Furthermore, as shown in FIG. 11, the reinforcing layer 9 may be disposed so as to wrap the entire bead core 51 and the bead filler 52. Thereby, the excessive flow of the bead filler 52 at the time of a tire vulcanization process is effectively suppressed.

  FIG. 12 is an explanatory view showing a modified example of the pneumatic tire according to the present embodiment.

  In the pneumatic tire 1 of the present embodiment, as shown in the meridional sectional view of the pneumatic tire according to the modified example of FIG. 12, the thermoplastic sheet (61, 62) has a maximum width in the tire width direction (maximum development in the tire width direction). Tire in the tire width direction at both ends C1 of the width (the thermoplastic sheet 61 in FIG. 12) is a belt layer (belt ply 71 in FIG. 12) having a maximum width in the tire width direction (maximum deployed width in the tire width direction). It is preferable to be located on the inner side in the tire width direction than the width direction end B1.

  According to this pneumatic tire 1, both ends C1 in the tire width direction of the thermoplastic sheet having the maximum width in the tire width direction (the thermoplastic sheet 61 in FIG. 12) are connected to the belt layer having the maximum width in the tire width direction (the belt ply in FIG. 12). 71), it is possible to prevent the end of each member from concentrating on the shoulder portion 3 by being configured to be located on the inner side in the tire width direction than the end portion B1 in the tire width direction. When the ends of the members are concentrated, a portion where the ends face each other becomes a bending point, and the pressure resistance and durability tend to be lowered. That is, according to the pneumatic tire 1, it is possible to suppress the generation of bending points and improve pressure resistance and durability.

  And since the part which wound up the thermoplastic sheet (61, 62) with the bead core 51 is arrange | positioned in the sidewall part 4, lamination | stacking of the thermoplastic sheet (61, 62) increases in the sidewall part 4 (in FIG. 12). 2 times). By comprising in this way, it becomes possible to ensure the pressure | voltage resistance of the side wall part 4, reducing the number of lamination | stacking of a thermoplastic sheet (61, 62) and improving the reduction | decrease of a tire weight.

  In FIG. 12, both ends C2 in the tire width direction of the thermoplastic sheet (thermoplastic sheet 62 in FIG. 12) which is not the maximum width in the tire width direction are also belt layers (belt ply 71 in FIG. 12) having the maximum width in the tire width direction. ) In the tire width direction from the end B1 in the tire width direction. By comprising in this way, it becomes possible to acquire the effect which suppresses generation | occurrence | production of a bending point more and improves pressure | voltage resistance and durability. In FIG. 12, both ends C1 in the tire width direction of the thermoplastic sheet having the maximum width in the tire width direction (the thermoplastic sheet 61 in FIG. 12) are connected to a belt layer (belt ply 72 in FIG. 12) that is not the maximum width in the tire width direction. ) In the tire width direction inner side than the end portion B2 in the tire width direction. By comprising in this way, it becomes possible to acquire the effect which suppresses generation | occurrence | production of a bending point more and improves pressure | voltage resistance and durability. Further, in FIG. 12, both ends C2 in the tire width direction of the thermoplastic sheet that is not the maximum width in the tire width direction (the thermoplastic sheet 62 in FIG. 12) are also belt layers that are not the maximum width in the tire width direction (the belt ply in FIG. 12). 72) in the tire width direction inner side than the end portion B2 in the tire width direction. By comprising in this way, it becomes possible to acquire the effect which suppresses generation | occurrence | production of a bending point more and improves pressure | voltage resistance and durability.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 12, the tire width direction both ends C1 of the thermoplastic sheet having the maximum width in the tire width direction (the thermoplastic sheet 61 in FIG. 12) are In the configuration in which the significant belt layer (belt ply 71 in FIG. 12) is positioned on the inner side in the tire width direction than the end B1 in the tire width direction, the thermoplastic sheets (61, 62) have the maximum width in the tire width direction. The distance CW between the tire width direction both ends (C1-C1) of the sheet (the thermoplastic sheet 61 in FIG. 12) and the tire width direction width BW of the belt layer (the belt ply 71 in FIG. 12) having the maximum width in the tire width direction. It is preferable that the relationship satisfies the range of 0.10 ≦ CW / BW ≦ 0.95.

  According to this pneumatic tire 1, both ends C1 in the tire width direction of the thermoplastic sheet having the maximum width in the tire width direction (the thermoplastic sheet 61 in FIG. 12) are connected to the belt layer having the maximum width in the tire width direction (the belt ply in FIG. 12). 71) The effect of improving the pressure resistance and the durability when configured to be located on the inner side in the tire width direction than the end B1 in the tire width direction can be remarkably obtained. In order to obtain the effect of improving pressure resistance and durability more remarkably, it is more preferable to satisfy the range of 0.15 ≦ CW / BW ≦ 0.95.

  In the pneumatic tire 1 of the present embodiment, the thermoplastic sheet (61, 62, 63) has a relationship between the tensile yield strength α with respect to the tire circumferential direction and the tensile yield strength β with respect to the tire width direction. It is preferable to satisfy the range of <β / α ≦ 5.

  According to this pneumatic tire 1, by making the tensile yield strength β in the tire width direction larger than the tensile yield strength α in the tire circumferential direction, the tire circumferential direction is easily deformed and the tire width direction is deformed. It becomes difficult. As a result, since the contact shape (contact length) of the tire can be made more appropriate, it is possible to improve steering stability.

  In the thermoplastic sheet (61, 62, 63), the relationship between the tensile yield strength α with respect to the tire circumferential direction and the tensile yield strength β with respect to the tire width direction is in the range of 1 <β / α ≦ 5. There are the following methods.

  For example, the stretch ratios of the thermoplastic sheet (61, 62, 63) in the tire circumferential direction and the tire width direction of the thermoplastic sheet (61, 62, 63) are varied to vary the rigidity.

  Furthermore, in order to give anisotropy to the thermoplastic sheet (61, 62, 63), a notch, a through hole, a non-penetrating recess, etc. are formed at any location of the thermoplastic sheet (61, 62, 63). It may be done (not shown).

[effect]
As described above, the pneumatic tire 1 is composed of the bead core 51, the bead filler 52 disposed on the outer side in the tire radial direction of the bead core 51, and the thermoplastic sheet, and the end portion is wound up on the outer side in the tire width direction. 51 and bead filler 52 are respectively disposed between carcass layers 61 to 63, sidewall rubber 41 disposed on the outer side in the tire width direction of the rolled-up portion of carcass layers 61 to 63, and bead filler 52 and sidewall rubber 41. And a reinforcing layer 9 covering the outer side surface of the bead filler 52 in the tire width direction (see FIG. 2).

  In such a configuration, (1) since the carcass layer 6 is made of the thermoplastic sheets 61 to 63, there is an advantage that the weight of the tire is reduced as compared with the configuration in which the carcass layer is formed by coating steel or organic fiber material with coat rubber. is there. Further, (2) in the tire vulcanization step, the reinforcing layer 9 functions as a backing material for the bead filler 52 and suppresses excessive flow of the bead filler 52. Thereby, the excessive deformation | transformation of the carcass layers 61-63 which consist of a thermoplastic sheet is suppressed, and there exists an advantage by which the buckle of the carcass layers 61-63 is suppressed.

  In the pneumatic tire 1, the reinforcing layer 9 covers at least 50% of the side surface of the bead filler 52 on the outer side in the tire width direction in a sectional view in the tire meridian direction (FIGS. 2 and 8). reference). Thereby, there exists an advantage by which the excessive flow of the bead filler 52 at the time of a tire vulcanization process is suppressed appropriately.

  Moreover, in this pneumatic tire 1, the reinforcement layer 9 consists of a composite material containing a fiber material. In such a configuration, the shape of the reinforcing layer 9 is appropriately secured at the time of the tire vulcanization process, so that an excessive flow of the bead filler 52 is appropriately suppressed.

  Moreover, in this pneumatic tire 1, the reinforcing layer 9 is formed by rolling a plurality of cord materials covered with cord rubber. In such a configuration, the shape of the reinforcing layer 9 is appropriately secured at the time of the tire vulcanization process, so that an excessive flow of the bead filler 52 is appropriately suppressed.

  In the pneumatic tire 1, the inclination angle θ of the cord material of the reinforcing layer 9 is in the range of 65 [deg] ≦ θ ≦ 90 [deg]. In such a configuration, the shape of the reinforcing layer 9 is appropriately secured at the time of the tire vulcanization process, so that an excessive flow of the bead filler 52 is appropriately suppressed.

  Further, in this pneumatic tire 1, the reinforcing layer 9 is made of a single rubber material, and the minimum torque measured by a rheometer under the measurement condition of the rubber material at a temperature of 170 [° C.] is 0.35 [ N · m] or more. Such a configuration has an advantage that the flow of the bead filler 52 is appropriately suppressed because the shape of the reinforcing layer 9 is appropriately ensured during the tire vulcanization process.

  Moreover, in this pneumatic tire 1, the reinforcement layer 9 is arrange | positioned so that the top part of the tire radial direction outer side of the bead filler 52 may be covered (refer FIG. 2). Thereby, there exists an advantage by which the excessive flow of the bead filler 52 at the time of a tire vulcanization process is suppressed effectively.

  In the pneumatic tire 1, the distance D between the end of the reinforcing layer 9 and the end of the bead filler 52 on the outer side in the tire radial direction is 5 [mm] ≦ D in a sectional view in the tire meridian direction. It is in range (see FIG. 2 and FIG. 10). In such a configuration, since the distance D between the end portion of the reinforcing layer 9 and the end portion of the bead filler 52 is appropriately secured, there is an advantage that the durability of the end portion of the reinforcing layer 9 is appropriately secured. Specifically, by separating the end portion of the reinforcing layer 9 and the end portion of the bead filler 52, the separation of the peripheral rubber starting from the end portion of the reinforcing layer 9 is suppressed.

  Moreover, in this pneumatic tire 1, the edge part of the reinforcement layer 9 is extended to the tire radial inside (bead bead core) of the bead core 51 (refer FIG. 9). In such a configuration, compared with a configuration in which the end portion of the reinforcing layer 9 does not extend to the inside in the tire radial direction of the bead core 51 (for example, see FIG. 2), the bead portion and the rim flange are rubbed during braking / driving of the vehicle. It is possible to effectively suppress the occurrence of separation with the end of the reinforcing layer 9 as a base point. Thereby, there exists an advantage by which the durability of the edge part of the reinforcement layer 9 is ensured appropriately.

  Moreover, in this pneumatic tire 1, the reinforcement layer 9 wraps the bead core 51 and extends to the inner side surface in the tire width direction of the bead filler 52 (see FIG. 10). Thereby, there exists an advantage by which the excessive flow of the bead filler 52 at the time of a tire vulcanization process is suppressed effectively.

  Further, the pneumatic tire 1 includes a rubber layer 6a interposed between the reinforcing layer 9 and the carcass layer 63 adjacent to the reinforcing layer 9 (see FIG. 2). That is, in the configuration in which the reinforcing layer 9 and the carcass layer 63 are disposed adjacent to each other, the rubber layer 6 a as a cushioning material is disposed between the reinforcing layer 9 and the carcass layer 63. Thereby, the mutual contact between the reinforcing layer 9 and the carcass layer 63 is prevented, and there is an advantage that damage to the carcass layer 63 is suppressed. This is particularly advantageous in a configuration in which the reinforcing layer 9 is made of a composite material including a fiber material. The rubber layer 6a may be a member that is previously laminated together with the carcass layers 61 to 63 to constitute the laminated body 60 (see FIG. 4), for example, a thick coat rubber formed on the reinforcing layer 9. It may be present (not shown).

Moreover, in this pneumatic tire 1, the average thickness of the thermoplastic sheets 61-63 exists in the range of 0.03 [mm] or more and 1.00 [mm] or less, and the thermoplastic sheets 61-63 are the same. The air permeability coefficient is in the range of 3 × 10 12 (cc · cm / cm ² · sec · cmHg) to 500 × 10 12 (cc · cm / cm ² · sec · cmHg). By the former, there exists an advantage by which the intensity | strength of the thermoplastic sheets 61-63 is ensured appropriately, and the latter has the advantage that the thermoplastic sheets 61-63 have a function as an inner liner.

  In the pneumatic tire 1, the peel strength between the rubber layer 6a and the thermoplastic sheets 61 to 63 is in the range of 50 [N / 25 mm] to 400 [N / 25 mm]. Thereby, there exists an advantage which the adhesiveness between the rubber layer 6a and the thermoplastic sheets 61-63 improves, and the durability of a tire improves.

Moreover, in this pneumatic tire 1, the rubber layer 6a is made of a rubber composition containing a condensate of the compound represented by the formula (1) and formaldehyde, a methylene donor, and a vulcanizing agent. In addition, R ¹ , R ² , R ³ , R ⁴ and R ⁵ in the formula (1) are hydrogen, a hydroxyl group, or an alkyl group having 1 to 8 carbon atoms. Moreover, the compounding quantity of a condensate exists in the range of 0.5 to 20 mass parts with respect to 100 mass parts of rubber components. Moreover, the compounding quantity of a methylene donor exists in the range of 0.5 to 80 mass parts with respect to 100 mass parts of rubber components. Moreover, the ratio of the blending amount of the methylene donor and the blending amount of the condensate is in the range of 1 or more and 4 or less. Thereby, there exists an advantage which the adhesiveness between the rubber layer 6a and the thermoplastic sheets 61-63 improves, and the durability of a tire improves.

  Moreover, in this pneumatic tire 1, the tensile yield strength of the thermoplastic sheets 61 to 63 at room temperature is in the range of 1 [MPa] to 100 [MPa]. Thereby, there exists an advantage which can ensure suitably the intensity | strength and manufacturability of the thermoplastic sheets 61-63.

  Moreover, in this pneumatic tire 1, the elongation at break of the thermoplastic sheets 61 to 63 at room temperature is in the range of 80 [%] to 500 [%]. Thereby, there exists an advantage which can ensure the intensity | strength of the thermoplastic sheets 61-63 appropriately.

  Moreover, in this pneumatic tire 1, the winding end part of the carcass layer 6 (in the structure having a plurality of carcass layers 61 to 63, the winding part that is the innermost in the tire width direction among the winding end parts of these carcass layers 61 to 63) The end portion C1) is located on the inner side in the tire width direction from the end portion on the outer side in the tire width direction of the widest belt ply 71 among the plurality of belt plies 71 and 72 (see FIG. 12). Thereby, concentration of the edge part of the tire member in the shoulder part 3 is suppressed, and there exists an advantage by which the pressure resistance and durability of a tire are ensured appropriately.

  Further, in the pneumatic tire 1, the right and left winding end portions of the carcass layer 6 (in the configuration having a plurality of carcass layers 61 to 63, the innermost in the tire width direction among the winding end portions of the carcass layers 61 to 63. A distance CW of a certain winding end C1) and a width BW of the widest belt ply 71 among the plurality of belt plies 71 and 72 have a relationship of 0.10 ≦ CW / BW ≦ 0.95 (FIG. 12). reference). Thereby, there exists an advantage by which the pressure resistance and durability of a tire are ensured appropriately.

  Moreover, in this pneumatic tire 1, the thermoplastic sheets 61-63 have orientation. Further, the tensile yield strength α in the tire circumferential direction of the thermoplastic sheets 61 to 63 and the tensile yield strength β in the tire width direction have a relationship of 1 <β / α ≦ 5. In this configuration, since the tensile yield strength β in the tire width direction of the thermoplastic sheets 61 to 63 is larger than the tensile yield strength α in the tire circumferential direction (1 <β / α), the thermoplastic sheets 61 to 63 are tires. It is easy to deform in the circumferential direction and difficult to deform in the tire width direction. Accordingly, there is an advantage that the ground contact shape (ground contact length) of the tire is appropriately ensured and the steering stability of the tire is improved.

  FIG. 13 is a chart showing the results of the performance test of the pneumatic tire according to the present embodiment.

  In this performance test, evaluations on (1) tire weight and (2) buckle resistance performance were performed on a plurality of different test tires (see FIG. 13). In this performance test, a test tire having a tire size of 235 / 40R18 is manufactured and used.

  (1) In the evaluation on the tire weight, the tire weight is measured, and an existing tire of a tire size 235 / 40R18 having a carcass layer formed by coating a cord material made of an organic fiber material with a coat rubber is used as a reference (100). Index evaluation is performed. In this evaluation, the smaller the numerical value, the smaller the tire weight, which is preferable.

  (2) For the evaluation on the buckle resistance, 16 types of test tires are prototyped and disassembled, and the presence or absence of occurrence of buckles (wrinkles) at the radially outer end of the bead filler is observed. If this buckle does not occur, it is appropriate.

  The test tires of Examples 1 to 6 have the configurations shown in FIGS. 1 and 2, and include a laminate 60 of carcass layers 61 to 63 made of a thermoplastic sheet and a rubber layer 6a. A single-layer reinforcing layer 9 is disposed so as to cover the side surface of the bead filler 52 on the outer side in the tire width direction. The reinforcing layer 9 is formed by rolling a plurality of cord materials covered with a coat rubber. Moreover, these test tires are manufactured by the manufacturing method of FIGS.

  The pneumatic tire of the comparative example does not include the reinforcing layer 9 in the configuration of FIG. Moreover, the carcass layers 61-63 have the carcass structure which laminated | stacked the thermoplastic sheet similarly to an Example.

In FIG. 13, the peel strength index between the rubber layer and the thermoplastic sheet is measured as follows. First, the laminated body which laminated | stacked the rubber layer and the thermoplastic sheet is shape | molded, This laminated body is vulcanized and cut | disconnected to width 25 [mm], and the strip-shaped test piece of a laminated body is created. And the peeling strength of this strip-shaped test piece is measured in accordance with JIS K6256, and is indexed in seven stages according to the following criteria (0) to (6). This evaluation is good if it is (1) or higher.
(0) ... 0 [N / 25 mm] or more and less than 20 [N / 25 mm] (1) ... 20 [N / 25 mm] or more and less than 25 [N / 25 mm] (2) ... 25 [N / 25 mm] or more and 50 [N / 25mm] (3) ... 50 [N / 25mm] or more and less than 75 [N / 25mm] (4) ... 75 [N / 25mm] or more and less than 100 [N / 25mm] (5) ... 100 [N / 25mm] More than 200 [N / 25mm] (6) ... 200 [N / 25mm] or more

  In FIG. 13, the number of plies of the carcass layer indicates the number of laminated thermoplastic sheets in the comparative example and each example. The number of plies in the “center portion” indicates the number of laminated thermoplastic sheets (comparative examples, Examples 1 to 6) on the tire equatorial plane CL, and the number of plies in the “side portion” indicates the heat at the tire maximum width position. The number of laminated plastic sheets (comparative examples, Examples 1 to 6) is shown.

  In FIG. 13, the arrangement region of the reinforcing layer 9 indicates the ratio of the extending range of the reinforcing layer 9 to the entire region L1 (see FIG. 8) on the outer side surface of the bead filler 52 in the tire width direction.

  As shown in the test results, it can be seen that in the pneumatic tires 1 of Examples 1 to 6, the tire is lightened and the occurrence of buckles is appropriately suppressed. Moreover, it turns out that the buckle-proof performance of a tire improves by arrangement | positioning of the reinforcement layer 9 being optimized.

  1: pneumatic tire, 2: tread part, 21: tread surface, 22: main groove, 23: land part, 3: shoulder part, 4: sidewall part, 41: sidewall rubber, 5: bead part, 51: Bead core, 52: Bead filler, 53: Rim cushion rubber, 60: Laminate, 6, 61-63: Carcass layer (thermoplastic sheet), 6a: Rubber layer, 7: Belt layer, 71, 72: Belt ply, 81 ˜83: belt reinforcing layer, 9: reinforcing layer

In the pneumatic tire 1 of the present embodiment, the thermoplastic sheet (61, 62, 63) forming the carcass layer 6 has a single layer average thickness of 0.03 [mm] or more and 1.00 [mm] or less. , and the and the air permeation coefficient of 3 × 10 ^ - be ^{12 [cc · cm / cm 2} · sec · cmHg] or less ^{- 12 [cc · cm / cm} 2 · sec · cmHg] or 500 × 10 ^ preferable.

Moreover, in this pneumatic tire 1, the average thickness of the thermoplastic sheets 61-63 exists in the range of 0.03 [mm] or more and 1.00 [mm] or less, and the thermoplastic sheets 61-63 are the same. air permeability coefficient, 3 × 10 ^ - in ^{12 [cc · cm / cm 2} · sec · cmHg] within the range of ^{- 12 [cc · cm / cm} 2 · sec · cmHg] or 500 × 10 ^. By the former, there exists an advantage by which the intensity | strength of the thermoplastic sheets 61-63 is ensured appropriately, and the latter has the advantage that the thermoplastic sheets 61-63 have a function as an inner liner.

Claims (19)

A bead core,
A bead filler disposed on the outer side in the tire radial direction of the bead core;
A carcass layer comprising a thermoplastic sheet and winding the end portion outward in the tire width direction so as to wrap each of the bead core and the bead filler;
Sidewall rubber disposed on the outer side in the tire width direction of the rolled-up portion of the carcass layer;
A pneumatic tire comprising: a reinforcing layer disposed between the bead filler and the sidewall rubber and covering a side surface of the bead filler on the outer side in the tire width direction.   The pneumatic tire according to claim 1, wherein the reinforcing layer covers at least 50% of the side surface of the bead filler on the outer side in the tire width direction in a cross-sectional view in the tire meridian direction.   The pneumatic tire according to claim 1, wherein the reinforcing layer is made of a composite material including a fiber material.   The pneumatic tire according to any one of claims 1 to 3, wherein the reinforcing layer is formed by rolling a plurality of cord materials coated with cord rubber.   The pneumatic tire according to claim 4, wherein the inclination angle θ of the cord material of the reinforcing layer is in a range of 65 [deg] ≦ θ ≦ 90 [deg].   The reinforcing layer is made of a single rubber material, and the minimum torque measured with a rheometer is within a range of 0.35 [N · m] or more under the measurement condition of the rubber material at a temperature of 170 ° C. The pneumatic tire according to any one of claims 1 to 5.   The pneumatic tire according to claim 1, wherein the reinforcing layer is disposed so as to cover a top portion of the bead filler on the outer side in the tire radial direction.   The distance D between the end portion of the reinforcing layer and the end portion of the bead filler on the outer side in the tire radial direction is in a range of 5 [mm] ≤ D in a sectional view in the tire meridian direction. The pneumatic tire according to any one of the above.   The pneumatic tire according to any one of claims 1 to 8, wherein the reinforcing layer extends to an inner side in a tire radial direction of the bead core.   The pneumatic tire according to any one of claims 1 to 9, wherein the reinforcing layer wraps around the bead core and extends to a side surface on the inner side in the tire width direction of the bead filler.   The pneumatic tire according to claim 1, further comprising a rubber layer interposed between the reinforcing layer and the carcass layer adjacent to the reinforcing layer. An average thickness of the thermoplastic sheet is in a range of 0.03 [mm] or more and 1.00 [mm] or less, and an air permeability coefficient of the thermoplastic sheet is 3 × 10 ^ 12 [cc · The pneumatic tire according to any one of claims 1 to 11, which is in a range of not less than cm / cm ² · sec · cmHg] and not more than 500 × 10 ^ 12 [cc · cm / cm ² · sec · cmHg].   The pneumatic tire according to any one of claims 1 to 12, wherein a peel strength between the rubber layer and the thermoplastic sheet is in a range of 50 [N / 25mm] to 400 [N / 25mm]. The rubber layer is composed of a rubber composition containing a condensate of the compound represented by formula (1) and formaldehyde, a methylene donor, and a vulcanizing agent,
R ¹ , R ² , R ³ , R ⁴ and R ^{5 in} formula (1) are hydrogen, a hydroxyl group, or an alkyl group having 1 to 8 carbon atoms,
The amount of the condensate is in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass of the rubber component,
The amount of methylene donor is in the range of 0.5 parts by weight to 80 parts by weight with respect to 100 parts by weight of the rubber component,
The pneumatic tire according to any one of claims 1 to 13, wherein a ratio between a blending amount of the methylene donor and a blending amount of the condensate is in a range of 1 or more and 4 or less.

  The pneumatic tire according to any one of claims 1 to 14, wherein a tensile yield strength of the thermoplastic sheet at room temperature is in a range of 1 [MPa] to 100 [MPa].   The pneumatic tire according to any one of claims 1 to 15, wherein the elongation at break of the thermoplastic sheet at room temperature is in a range of 80 [%] to 500 [%].   The wound-up end portion of the carcass layer is located on the inner side in the tire width direction from the end portion on the outer side in the tire width direction of the widest belt ply among the plurality of belt plies constituting the carcass layer. The pneumatic tire according to one.   The distance CW between the left and right winding ends of the carcass layer and the width BW of the widest belt ply among the plurality of belt plies have a relationship of 0.10 ≦ CW / BW ≦ 0.95. The pneumatic tire according to any one of ˜17. The thermoplastic sheet has orientation, and
The tensile yield strength α in the tire circumferential direction of the thermoplastic sheet and the tensile yield strength β in the tire width direction have a relationship of 1 <β / α ≦ 5. The described pneumatic tire.

Images