JP2014234126A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve weight saving of tire weight and riding comfortableness, and to improve stability.SOLUTION: The pneumatic tire comprises: at least one carcass layer 6 in which plural cords are disposed in a tire circumferential direction and having a segmentation part 6A whose both ends in a tire width direction reach both bead parts 5, and being hooked to the tire circumferential direction, and being segmented in the tire width direction on a tread part 2; and at least one belt layer 7 disposed on outside of the carcass layer 6 in a tire radial direction on the tread part 2. The pneumatic tire further comprises thermoplastic resin film layers 8 disposed in a separated state in the tire width direction so as to open the segmentation part 6A of the carcass layer 6, laminated on the carcass layer 6 and extending in the respective bead parts 5 sides, and having storage elastic modulus of 50 MPa or more and 500 MPa or less.

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a split carcass structure.

  Conventionally, for example, in Patent Document 1, a radial carcass layer of one ply or more and a belt layer of two or more rubber-coated cord crossing layers are provided, and the carcass layer has one or more cords on a ply in the arrangement region of the belt layer. The total width in the tire axial direction of the cord dividing portion has a value of 90% or less of the maximum belt width, and the folded portion of the carcass layer has a height of 35 mm or less as measured from the rim diameter line. Tires are shown.

  Further, for example, in Patent Document 2, a plurality of belt layers are provided on the inner peripheral side of the tread, and a plurality of carcass layers are laminated on the inner peripheral side of the belt layer, and both end portions of these carcass layers are In a pneumatic tire wound up with a bead core of a bead portion, at least one of the plurality of carcass layers has a pair of divided plies divided in the tire width direction at a predetermined interval in the tire axial direction. In the carcass layer having the split ply structure, the gap is narrower than the minimum belt width in the belt layer, and each split ply has a tire equatorial plane. Pneumatic tires are shown which are arranged in symmetrical positions with respect to.

JP 2001-187511 A JP-A-6-247102

  As in Patent Document 1 described above, by providing a split portion in the carcass layer, an effect of reducing the tire weight can be obtained, and an effect of improving riding comfort performance can be obtained by reducing the rigidity of the tread portion. However, by removing the carcass layer under the belt layer, the tension of the carcass layer is greatly reduced, and as a result, the steering stability performance may be lowered.

  On the other hand, in Patent Document 2 described above, by reducing the number of carcass layers, it is possible to suppress a decrease in durability performance starting from the split end of the carcass layer. However, if another carcass layer is disposed at the split portion of the carcass layer, as a result, the effect of reducing the tire weight and the effect of improving the riding comfort performance are impaired.

  The present invention has been made in view of the above, and an object of the present invention is to provide a pneumatic tire capable of improving the steering stability performance while reducing the weight of the tire and improving the riding comfort performance. To do.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the first invention is provided with a plurality of cords provided side by side in the tire circumferential direction, and both ends in the tire width direction reach both bead portions in the tire circumferential direction. At least one carcass layer having a divided portion that is provided around the tread portion and is divided in the tire width direction, and at least one belt layer that is disposed outside the carcass layer in the tire radial direction in the tread portion. A pneumatic tire having a structure that is separated in the tire width direction so as to open the dividing portion of the carcass layer, and is stacked on the carcass layer and provided to extend to each of the bead portions. A thermoplastic resin film layer having a rate of 50 MPa or more and 500 MPa or less is provided.

  According to this pneumatic tire, the weight of the pneumatic tire can be reduced because the tire weight can be reduced by providing the dividing portion in the carcass layer. For this reason, rolling resistance can be reduced, the fuel consumption of the vehicle can be reduced, and the ride performance can be improved by reducing the rigidity of the tread portion. In addition, the thermoplastic resin film layer that is laminated on the carcass layer and extends to each bead side and has a storage elastic modulus of 50 MPa or more and 500 MPa or less is provided with a reinforcing layer having a rubber material or a cord. Compared to the light weight and high rigidity, the steering stability performance can be improved by complementing the tire rigidity while reducing the weight. Moreover, since the thermoplastic resin film layer is provided separately in the tire width direction so as to open the cut portion of the carcass layer, the effect of reducing the weight of the pneumatic tire and the ride comfort by reducing the rigidity of the tread portion are provided. The performance improvement effect can be maintained. As a result, the weight of the tire can be reduced, the ride performance can be improved, and the steering stability can be improved.

  The pneumatic tire of the second invention is characterized in that, in the first invention, the thickness of the thermoplastic resin film layer is 0.02 mm or more and 0.5 mm or less.

  According to this pneumatic tire, by setting the thickness of the thermoplastic resin film layer to 0.02 mm or more, the tire rigidity can be complemented and the improvement effect of the steering stability performance can be remarkably obtained. On the other hand, by setting the thickness of the thermoplastic resin film layer to 0.5 mm or less, it is possible to suppress excessive tire rigidity and to significantly improve the riding comfort performance.

  In the pneumatic tire according to the third invention, in the first or second invention, the thickness of the rubber material between the thermoplastic resin film layer and the cord of the carcass layer is 0.1 mm or more and 0.00. It is characterized by being 8 mm or less.

  According to this pneumatic tire, by setting the thickness of the rubber material between the thermoplastic resin film layer and the cord of the carcass layer to be 0.1 mm or more, between the cord of the carcass layer and the thermoplastic resin film layer. Since a rubber material is appropriately interposed in the tire, excessive tire rigidity can be suppressed and the effect of improving riding comfort performance can be remarkably obtained. On the other hand, when the thickness of the rubber material between the thermoplastic resin film layer and the cord of the carcass layer is 0.8 mm or less, the tire rigidity can be complemented and the improvement effect of the steering stability performance can be remarkably obtained.

  The pneumatic tire according to a fourth aspect of the present invention is the pneumatic tire according to any one of the first to third aspects, wherein the thermoplastic resin film layer has the carcass layer from both ends of the belt layer in the tire width direction maximum width. It is characterized by being provided within a range of 10% of the tire cross-section height from the position where the reference lines perpendicular to the normal line are respectively drawn to the inside in the tire radial direction.

  According to this pneumatic tire, the weight of the pneumatic tire can be reduced because the tire weight can be reduced by providing the dividing portion in the carcass layer. For this reason, rolling resistance can be reduced, the fuel consumption of the vehicle can be reduced, and the ride performance can be improved by reducing the rigidity of the tread portion. In addition, the thermoplastic resin film layer that is laminated on the carcass layer and extends to each bead side and has a storage elastic modulus of 50 MPa or more and 500 MPa or less is provided with a reinforcing layer having a rubber material or a cord. Compared to the light weight and high rigidity, the steering stability performance can be improved by complementing the tire rigidity while reducing the weight. Moreover, since the thermoplastic resin film layer is provided separately in the tire width direction so as to open the cut portion of the carcass layer, the effect of reducing the weight of the pneumatic tire and the ride comfort by reducing the rigidity of the tread portion are provided. The performance improvement effect can be maintained. In addition, the thermoplastic resin film layer has a tire cross-section height at the inner side in the tire radial direction from the positions where the reference lines perpendicular to the normal line of the carcass layer are drawn from both ends of the belt layer in the tire width direction maximum width. Since it is provided in the range of 10%, it is possible to achieve both the effect of improving the riding comfort performance by reducing the rigidity of the tread portion and the effect of improving the steering stability performance by complementing the tire rigidity while further reducing the weight. As a result, the weight of the tire can be reduced, the ride performance can be improved, and the steering stability can be improved.

The pneumatic tire of the fifth invention is the pneumatic tire according to any one of the first to fourth inventions, wherein the thermoplastic resin film layer has an air permeability coefficient of 50 · 10 ⁻¹² · cc · cm / cm ² · sec. A rubber composition mainly composed of butyl rubber and bonded to the thermoplastic resin film layer is provided in a portion that does not have the thermoplastic resin film layer, and the thermoplastic resin film layer is bonded to the thermoplastic resin film layer. A tire inner peripheral surface is constituted by the layer and the rubber layer.

  According to this pneumatic tire, since the thermoplastic resin film layer also serves as an inner liner that suppresses permeation of air molecules to the outside of the tire, the weight of the tire can be further reduced, so that the weight of the pneumatic tire is further reduced. be able to. For this reason, it is possible to further reduce rolling resistance and further reduce fuel consumption of the vehicle.

The pneumatic tire according to a sixth aspect of the present invention is the pneumatic tire according to any one of the first to third aspects, wherein the thermoplastic resin film layer has an air permeability coefficient of 50 · 10 ⁻¹² · cc · cm / cm ² · sec. A rubber composition mainly composed of butyl rubber and bonded to the thermoplastic resin film layer is provided in a portion that does not have the thermoplastic resin film layer, and the thermoplastic resin film layer is bonded to the thermoplastic resin film layer. A tire inner peripheral surface is constituted by a layer and the rubber layer, and an inner end in the tire width direction of the thermoplastic resin film layer is folded back and arranged at a divided end of the divided portion of the carcass layer. .

  According to this pneumatic tire, since the thermoplastic resin film layer also serves as an inner liner that suppresses permeation of air molecules to the outside of the tire, the weight of the tire can be further reduced, so that the weight of the pneumatic tire is further reduced. be able to. For this reason, it is possible to further reduce rolling resistance and further reduce fuel consumption of the vehicle. In addition, by arranging the inner end in the tire width direction of the thermoplastic resin film layer at the dividing end of the dividing portion of the carcass layer, the air leakage resistance can be improved and the durability performance can be improved.

  The pneumatic tire according to the present invention can reduce the weight of the tire, improve the riding comfort performance, and improve the steering stability performance.

FIG. 1 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a meridional sectional view of the pneumatic tire according to the embodiment of the present invention. FIG. 3 is a meridional sectional view of the pneumatic tire according to the embodiment of the present invention. FIG. 4 is a partial enlarged meridional section of a pneumatic tire according to an embodiment of the present invention. FIG. 5 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 6 is a meridional sectional view of the pneumatic tire according to the embodiment of the present invention. FIG. 7 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 8 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 9 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 10 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 11 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 12 is a chart showing test results according to examples of the present invention. FIG. 13 is a chart showing test results according to examples of the present invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

  1 to 3 are meridional sectional views of the pneumatic tire according to the present embodiment, FIG. 4 is a partial enlarged meridional section of the pneumatic tire according to the present embodiment, and FIGS. It is a meridional sectional view of the pneumatic tire according to the present 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 thermoplastic resin film 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 constitutes the belt material of the present embodiment, and both end portions in the tire width direction are wound up from the inner side in the tire width direction to the outer side in the tire width direction by a pair of bead cores 51 and extend outward in the tire radial direction. In addition, the tire skeleton is constructed by being toroidally wound in the tire circumferential direction. The carcass layer 6 is provided as at least one layer. The carcass layer 6 is formed by coating a plurality of cords 6a arranged in parallel at an angle in the tire circumferential direction with an angle with respect to the tire circumferential direction along the tire meridian direction (see FIG. 4). The cord 6a of the carcass layer 6 is made of organic fibers (polyester, rayon, nylon, etc.).

  The carcass layer 6 includes a divided portion 6A that is divided in the tire width direction by the tread portion 2. That is, in the pneumatic tire of the present embodiment, the carcass layer 6 is divided at the tread portion 2 in the tire width direction, and the respective divided ends 6Aa are separated. 6 A of division parts are provided in the position centering on tire equator surface CL in the figure, However, You may provide in the tire width direction. Thus, the pneumatic tire of the present embodiment has a split carcass structure.

  In addition, it is preferable that the carcass layer 6 is divided in a range where the tire width direction dimension W2 of the dividing portion 6A is 5% or more and 95% or less of the maximum width W1 of the belt layer 7 in the tire width direction.

  In the case of a plurality of belt layers 7, the maximum width W1 in the tire width direction of the belt layer 7 is the tire width direction dimension of the belt having the largest tire width direction dimension (the belt layer 7A in this embodiment).

  By making the tire width direction dimension W2 of the dividing portion 6A 5% or more of the maximum width W1 of the belt layer 7 in the tire width direction, the effect of reducing the weight of the pneumatic tire 1 can be significantly obtained. On the other hand, by setting the tire width direction dimension W2 of the dividing portion 6A to 95% or less of the maximum width W1 of the belt layer 7 in the tire width direction, deterioration of durability can be prevented. Therefore, it is preferable to provide the dividing portion 6A in the range of 5% to 95% of the maximum width W1 of the belt layer 7 in the tire width direction.

  The belt layer 7 includes at least one belt layer, and is disposed on the outer side in the tire radial direction that 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. The belt layer 7 in this embodiment has a multilayer structure in which two belt layers 7A and 7B are laminated from the inner side in the tire radial direction. The belt layers 7A and 7B are formed by coating a plurality of cords arranged in parallel at a predetermined angle (for example, 20 degrees to 30 degrees) with a coat rubber with respect to the tire circumferential direction. The cord of the belt layer 7 is made of steel or organic fiber (polyester, rayon, nylon, etc.). The overlapping belt layers 7A and 7B are arranged so that the cords intersect each other.

  The thermoplastic resin film layer 8 is a film that does not have a cord, and is separated in the tire width direction so as to open the dividing portion 6A of the carcass layer 6, and is laminated on the carcass layer 6 to beside each bead portion 5. Each extends. That is, the thermoplastic resin film layer 8 is divided in the tire width direction at the tread portion 2 in the same manner as the carcass layer 6, and the divided portion overlaps with the divided portion 6A of the carcass layer 6, and the divided portion 6A is overlapped. It is provided to open. The thermoplastic resin film layer 8 has a storage elastic modulus of 50 MPa or more and 500 MPa or less.

  The thermoplastic resin film layer 8 is preferably composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer component in a thermoplastic resin.

  Here, 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 Recall copolymer, PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer and other aromatic polyesters], polynitrile Resin (for example, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer), poly (meth) Acrylate resins [for example, polymethyl methacrylate (PMMA), polyethyl methacrylate, ethylene ethyl acrylate copolymer (EEA), ethylene acrylic acid copolymer (EAA), ethylene methyl acrylate resin (EMA)], poly Nyl resins [eg, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer , Vinylidene chloride / methyl acrylate copolymer], cellulose resin [eg cellulose acetate, cellulose acetate butyrate], fluororesin [eg polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE) , Tetrafluoroethylene / ethylene copolymer (ETFE)], imide resins [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.

  Such a thermoplastic resin film layer 8 is provided inside the carcass layer 6 and at the position of the sidewall portion 4 as shown in FIG. Further, as shown in FIG. 2, the thermoplastic resin film layer 8 is provided on the inner side of the carcass layer 6 and spans from the tread portion 2 to the bead portion 5. Further, as shown in FIG. 3, the thermoplastic resin film layer 8 is provided outside the carcass layer 6 and at a position of the sidewall portion 4. Although not shown in the drawing, the thermoplastic resin film layer 8 is provided inside or outside the carcass layer 6 and spans from the tread portion 2 to the sidewall portion 4.

  Thus, in the pneumatic tire 1 of the present embodiment, the plurality of cords 6a are provided side by side in the tire circumferential direction, and both ends in the tire width direction reach both the bead portions 5 and are provided around the tire circumferential direction. 2 and having at least one carcass layer 6 having a divided portion 6A divided in the tire width direction, and at least one belt layer 7 disposed outside the carcass layer 6 in the tire radial direction in the tread portion 2. The carcass layer 6 is separated in the tire width direction so as to open the dividing portion 6A, is laminated on the carcass layer 6 and extends to each bead portion 5 side, and has a storage elastic modulus of 50 MPa to 500 MPa. The following thermoplastic resin film layer 8 is provided.

  According to the pneumatic tire 1, the weight of the pneumatic tire 1 can be reduced because the tire weight can be reduced by providing the dividing portion 6 </ b> A in the carcass layer 6. For this reason, rolling resistance can be reduced, fuel consumption of the vehicle can be reduced, and riding comfort performance can be improved by reducing the rigidity of the tread portion 2. Moreover, the thermoplastic resin film layer 8 laminated on the carcass layer 6 and extending to the side of each bead portion 5 and having a storage elastic modulus of 50 MPa or more and 500 MPa or less is a reinforcing layer having a rubber material or a cord. Since it is lighter and higher in rigidity than the configuration provided, it is possible to improve steering stability performance by complementing tire rigidity while achieving weight reduction. In addition, since the thermoplastic resin film layer 8 is provided separately in the tire width direction so as to open the dividing portion 6A of the carcass layer 6, the effect of reducing the weight of the pneumatic tire 1 and the low tread portion 2 are achieved. It is possible to maintain the effect of improving the ride comfort performance due to the rigidity. As a result, the weight of the tire can be reduced, the ride performance can be improved, and the steering stability can be improved.

  Moreover, in the pneumatic tire 1 of this embodiment, as shown in FIG. 4, it is preferable that the thickness H1 of the thermoplastic resin film layer 8 is 0.02 mm or more and 0.5 mm or less.

  By setting the thickness H1 of the thermoplastic resin film layer 8 to be 0.02 mm or more, the tire rigidity can be complemented and the improvement effect of the steering stability performance can be significantly obtained. On the other hand, by setting the thickness of the thermoplastic resin film layer 8 to 0.5 mm or less, it is possible to suppress excessive tire rigidity and to significantly improve the riding comfort performance.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 4, the thickness H2 of the rubber material between the thermoplastic resin film layer 8 and the cord 6a of the carcass layer 6 is 0.1 mm or more and 0.0. It is preferable to be 8 mm or less.

  Here, the rubber material between the thermoplastic resin film layer 8 and the cord 6 a of the carcass layer 6 is not only the coat rubber 6 b of the carcass layer 6 but also a tie rubber that joins the thermoplastic resin film layer 8 and the carcass layer 6. In the case where tie rubber is not included, the coat rubber 6b of the carcass layer 6 is a rubber material.

  By setting the thickness H2 of the rubber material between the thermoplastic resin film layer 8 and the cord 6a of the carcass layer 6 to be 0.1 mm or more, between the cord 6a of the carcass layer 6 and the thermoplastic resin film layer 8 Since the rubber material is appropriately interposed, excessive tire rigidity can be suppressed, and the effect of improving riding comfort performance can be remarkably obtained. On the other hand, by setting the thickness H2 of the rubber material between the thermoplastic resin film layer 8 and the cord 6a of the carcass layer 6 to 0.8 mm or less, the tire rigidity is complemented and the effect of improving the steering stability performance is remarkably obtained. be able to.

  In the pneumatic tire 1 of the present embodiment, as shown in FIG. 5, the thermoplastic resin film layer 8 is perpendicular to the normal line of the carcass layer 6 from both ends of the belt layer 7 in the tire width direction maximum width W1. It is preferable that the reference line L is provided within a range of 10% of the tire cross-section height SH from the position where each of the reference lines L is drawn to the inside in the tire radial direction.

  Here, the tire cross-section height HS is ½ of the difference between the outer diameter and the rim diameter of the tire in a no-load state (normal load 0%) in which the tire is assembled on the normal rim and filled with the normal internal pressure. .

  The regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The normal load is “maximum load capacity” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO.

  According to the pneumatic tire 1, the weight of the pneumatic tire 1 can be reduced because the tire weight can be reduced by providing the dividing portion 6 </ b> A in the carcass layer 6. For this reason, rolling resistance can be reduced, fuel consumption of the vehicle can be reduced, and riding comfort performance can be improved by reducing the rigidity of the tread portion 2. Moreover, the thermoplastic resin film layer 8 laminated on the carcass layer 6 and extending to the side of each bead portion 5 and having a storage elastic modulus of 50 MPa or more and 500 MPa or less is a reinforcing layer having a rubber material or a cord. Since it is lighter and higher in rigidity than the configuration provided, it is possible to improve steering stability performance by complementing tire rigidity while achieving weight reduction. In addition, since the thermoplastic resin film layer 8 is provided separately in the tire width direction so as to open the dividing portion 6A of the carcass layer 6, the effect of reducing the weight of the pneumatic tire 1 and the low tread portion 2 are achieved. It is possible to maintain the effect of improving the ride comfort performance due to the rigidity. In addition, the thermoplastic resin film layer 8 is formed at the inner side in the tire radial direction from the positions where the reference lines L perpendicular to the normal line of the carcass layer 6 are drawn from both ends of the maximum width W1 of the belt layer 7 in the tire width direction. Since it is provided in the range of 10% of the tire cross-section height SH, while improving weight reduction effect of the ride comfort performance by lowering the rigidity of the tread part 2, and the improvement effect of steering stability performance by complementing the tire rigidity Can be compatible. As a result, the weight of the tire can be reduced, the ride performance can be improved, and the steering stability can be improved.

  Moreover, in the pneumatic tire 1 of this embodiment, as shown in FIG. 6, the tire width direction inner side end 8a of the thermoplastic resin film layer 8 and the divided end 6Aa of the divided part 6A of the carcass layer 6 are matched. It is preferable.

  According to this pneumatic tire 1, since it becomes easy to manufacture by aligning the tire width direction inner side end 8a of the thermoplastic resin film layer 8 and the divided end 6Aa of the divided part 6A of the carcass layer 6, productivity is improved. Can be improved.

  Moreover, in the pneumatic tire 1 of the present embodiment, as shown in FIGS. 7 and 8, the inner end 8 a in the tire width direction of the thermoplastic resin film layer 8, and the divided end 6 Aa of the divided portion 6 A of the carcass layer 6, Is preferably shifted by 2 mm or more in the tire width direction.

  That is, an overlap portion r is provided in which an end portion in the tire width direction of the thermoplastic resin film layer 8 and a split end portion of the split portion 6A of the carcass layer 6 are overlapped with each other. 2 mm or more in the direction. In FIG. 7, the cut end 6 </ b> Aa of the cut portion 6 </ b> A of the carcass layer 6 is arranged on the inner side in the tire width direction than the inner end 8 a in the tire width direction of the thermoplastic resin film layer 8. The inner end 8a in the tire width direction is arranged on the inner side in the tire width direction with respect to the dividing end 6Aa of the dividing portion 6A of the carcass layer 6.

  According to this pneumatic tire 1, the inner end 8a in the tire width direction of the thermoplastic resin film layer 8 and the divided end 6Aa of the divided portion 6A of the carcass layer 6 are shifted by 2 mm or more in the tire width direction. Thus, mutual edge separation resistance can be improved. In addition, as shown in FIG. 8, when the tire width direction inner side edge 8a of the thermoplastic resin film layer 8 is disposed on the inner side in the tire width direction than the divided edge 6Aa of the divided part 6A of the carcass layer 6, the overlap part It is preferable that the tire width direction dimension of r is 50% or less of the tire width direction dimension W2 of the dividing portion 6A in order to obtain the effect of improving riding comfort performance.

Further, in the pneumatic tire 1 of the present embodiment, the air permeability coefficient of the thermoplastic resin film layer 8 is set to 50 · 10 ⁻¹² · cc · cm / cm ² · sec · cmHg or less, as shown in FIG. 9 and FIG. A rubber layer 9, which is a rubber composition mainly composed of butyl rubber and joined to the thermoplastic resin film layer 8, is provided in a portion not having the thermoplastic resin film layer 8, and the thermoplastic resin film layer 8 and It is preferable that the tire inner peripheral surface is constituted by the rubber layer 9.

That is, the air permeability coefficient of the thermoplastic resin film layer 8 is 50 · 10 ⁻¹² · cc · cm / cm ² · sec · cmHg or less, and the rubber layer 9 is a rubber composition mainly composed of butyl rubber. Are joined together to form the tire inner peripheral surface by the thermoplastic resin film layer 8 and the rubber layer 9, so that the thermoplastic resin film layer 8 and the rubber layer 9 function as an inner liner.

  The inner liner is provided on the inner circumferential surface of the carcass layer 6 on the inner side of the tire so that both ends in the tire width direction reach a pair of bead portions 5 and are wound around in a toroidal shape in the tire circumferential direction. This is to suppress the permeation of air molecules. Each end portion of the inner liner may terminate at the side of the bead portion 5 on the tire inner peripheral surface, or may be wound up outside the bead portion 5.

Here, the air permeation coefficient is a value specific to the material representing the air permeation factor (unit: [10 ⁻¹² · cc · cm / cm ² · sec · cmHg]), includes the thickness of the material, and has a temperature of 30 In accordance with JIS K 7126-7 at ° C. Plastic-film and sheet-gas permeability test method-Part 1: Measured by differential pressure method.

The air permeation amount is the amount of air per unit time per unit time (unit: [10 ⁻¹² · cc / cm ² · sec · cmHg]) and conforms to JIS K 7126-7 at a temperature of 30 ° C. Plastics-films and sheets-Gas permeability test method-Part 1: Measured by the differential pressure method. The average air permeation amount is an average value of air permeation amounts of a plurality of samples.

  Examples of the rubber composition mainly composed of butyl rubber used in the present embodiment include butyl rubber (IIR) and halogenated butyl rubber (Br-IIR, Cl-IIR). These can use what is marketed. As the butyl rubber, halogenated butyl rubber is preferable. Examples of the halogenated butyl rubber include chlorinated butyl rubber and brominated butyl rubber.

  According to this pneumatic tire 1, since the thermoplastic resin film layer 8 also serves as an inner liner that suppresses the permeation of air molecules to the outside of the tire, the weight of the tire can be further reduced. Can be further planned. For this reason, it is possible to further reduce rolling resistance and further reduce fuel consumption of the vehicle.

In the pneumatic tire 1 of the present embodiment, the air permeability coefficient of the thermoplastic resin film layer 8 is 50 · 10 ⁻¹² · cc · cm / cm ² · sec · cmHg or less, and as shown in FIG. A rubber layer 9 which is a rubber composition mainly composed of butyl rubber and joined to the thermoplastic resin film layer 8 is provided in a portion which does not have the plastic resin film layer 8, and the thermoplastic resin film layer 8 and the rubber layer 9 are provided. It is preferable that the inner peripheral surface of the tire is configured by the above and the inner end 8a in the tire width direction of the thermoplastic resin film layer 8 is folded back to the divided end 6Aa of the divided portion 6A of the carcass layer 6.

That is, the air permeability coefficient of the thermoplastic resin film layer 8 is 50 · 10 ⁻¹² · cc · cm / cm ² · sec · cmHg or less, and the rubber layer 9 is a rubber composition mainly composed of butyl rubber. Are joined together to form the tire inner peripheral surface by the thermoplastic resin film layer 8 and the rubber layer 9, so that the thermoplastic resin film layer 8 and the rubber layer 9 function as an inner liner.

  The inner liner is provided on the inner circumferential surface of the carcass layer 6 on the inner side of the tire so that both ends in the tire width direction reach a pair of bead portions 5 and are wound around in a toroidal shape in the tire circumferential direction. This is to suppress the permeation of air molecules. Each end portion of the inner liner may terminate at the side of the bead portion 5 on the tire inner peripheral surface, or may be wound up outside the bead portion 5.

  According to this pneumatic tire 1, since the thermoplastic resin film layer 8 also serves as an inner liner that suppresses the permeation of air molecules to the outside of the tire, the weight of the tire can be further reduced. Can be further planned. For this reason, it is possible to further reduce rolling resistance and further reduce fuel consumption of the vehicle. Moreover, by arranging the inner end 8a in the tire width direction of the thermoplastic resin film layer 8 so as to be folded back to the cut end 6Aa of the cut portion 6A of the carcass layer 6, the air leakage resistance is improved and the durability is improved. be able to.

  In the embodiment described above, the carcass layer 6 is shown as a single layer in the figure, but may be a plurality of layers. In this case, although not shown in the drawing, the dividing portion 6A only needs to be provided in at least one carcass layer 6. When the carcass layer 6 is a single layer, the carcass layer 6 itself is not divided, and the end portion folded at the bead portion 5 is the tire diameter of the belt layer 7 of the tread portion 2, although not clearly shown in the figure. The form which has 6 A of parting parts with the form extended in the direction inner side and having opposed and separated may be sufficient. When the carcass layer 6 has a plurality of layers, the thermoplastic resin film layer 8 is disposed on the inner side in the tire radial direction of all the carcass layers 6, on the outer side in the tire radial direction of all the carcass layers 6, or between the carcass layers 6. The

  12 and 13 are tables showing test results according to this example. In this example, a plurality of types of pneumatic tires with different conditions were tested for tire weight, durability performance, steering stability performance, and riding comfort performance.

  In this test, a pneumatic tire having a tire size of 235 / 40R18 was used as a test tire.

  The tire weight is evaluated by measuring the weight of the test tire with a measuring instrument. Then, based on the measurement result, index evaluation using the conventional example as a reference (100) is performed. This index evaluation indicates that the larger the value is 95 or more, the lighter and better the tire weight.

  The evaluation method of durability performance is as follows. The test tire is assembled on a regular rim, filled with a regular internal pressure (240 kPa), and attached to a drum testing machine having a drum diameter of 1707 mm, at a speed of 82 km / h, and an ambient temperature of 38 ° C. ± 3 ° C. The load is increased by 13% every 2 hours from 88% of the normal load under the conditions of, and the time until the belt layer generates separation is measured. Then, based on the measurement result, index evaluation using the conventional example as a reference (100) is performed. This index evaluation shows that the larger the value is 95 or more, the better the durability performance is.

  Steering stability performance is evaluated by assembling a rim on the above test tire regular rim, filling a regular internal pressure (240 kPa), and mounting it on a test vehicle (displacement 2.0L domestic FF passenger car), and has a flat circuit. The test course is run at a speed of 60 km / h to 120 km / h, and a feeling test is conducted by three panelists on the items of steering performance at the time of lane change and cornering, and straight running stability at the time of straight running. Then, an index evaluation is performed in which an average of three test results is expressed as an index using the conventional example as a reference (100). This index evaluation indicates that the steering stability performance is better as the index is 95 or higher.

  Riding comfort performance is evaluated by assembling the rim on the above-mentioned test tire regular rim, filling the regular internal pressure (240 kPa), and mounting it on a test vehicle (2.0 L domestically produced FF passenger car), having unevenness with a step of 10 mm. A straight test course is run at 50km / h, and a feeling test of ride comfort is conducted by three panelists. Then, an index evaluation is performed in which an average of three test results is expressed as an index using the conventional example as a reference (100). This index evaluation shows that the ride performance is better as the index is 95 or higher.

  As shown in FIG. 12, Conventional Example 1 has a split portion in the carcass layer, and has a reinforcing layer made of a rubber material along the entire carcass layer.

  On the other hand, as shown in FIG. 12 and FIG. 13, Examples 1 to 19 do not have the reinforcing layer of Conventional Example 1, have a split part in the carcass layer, and open the split part of the carcass layer. A thermoplastic resin film layer is provided that is separated in the tire width direction, is laminated on the carcass layer and extends to each bead portion side, and has a storage elastic modulus of 50 MPa or more and 500 MPa or less.

  In Conventional Example 1 and Examples 1 to 19, the carcass layer is one layer, and the dividing portion is provided in the center of the tire width direction in a range of 60% of the maximum width of the belt layer in the tire width direction. ing.

  As shown in the test results of FIGS. 12 and 13, the pneumatic tires of Examples 1 to 19 achieve a reduction in tire weight and an improvement in riding comfort performance, and an improvement in driving stability performance. I understand that.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 5 Bead part 6 Carcass layer 6a Cord 6b Coat rubber 6A Divided part 6Aa Divided end 7 Belt layer 8 Thermoplastic resin film layer 9 Rubber layer L Reference line

Claims (6)

A plurality of cords are provided side by side in the tire circumferential direction, and at least one layer having a split portion that is provided by extending both ends in the tire width direction to both bead portions and being wound around in the tire circumferential direction and divided in the tire width direction by the tread portion. In a pneumatic tire having a carcass layer, and at least one belt layer disposed on the outer side in the tire radial direction of the carcass layer in the tread portion,
Heat that is separated in the tire width direction so as to open the dividing portion of the carcass layer, is laminated on the carcass layer and extends to each bead portion side, and has a storage elastic modulus of 50 MPa or more and 500 MPa or less A pneumatic tire comprising a plastic resin film layer.   2. The pneumatic tire according to claim 1, wherein a thickness of the thermoplastic resin film layer is set to 0.02 mm or more and 0.5 mm or less.   The pneumatic tire according to claim 1 or 2, wherein a thickness of a rubber material between the thermoplastic resin film layer and the cord of the carcass layer is 0.1 mm or more and 0.8 mm or less.   The thermoplastic resin film layer has a tire cross-section height inward in the tire radial direction from a position where a reference line perpendicular to the normal line of the carcass layer is drawn from both ends of the belt layer in the tire width direction maximum width. The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is provided in a range of 10%. A rubber mainly composed of butyl rubber in a portion where the thermoplastic resin film layer has an air permeability coefficient of 50 · 10 ⁻¹² · cc · cm / cm ² · sec · cmHg or less and does not have the thermoplastic resin film layer 5. The composition according to claim 1, wherein a rubber layer bonded to the thermoplastic resin film layer is provided, and a tire inner peripheral surface is constituted by the thermoplastic resin film layer and the rubber layer. A pneumatic tire according to any one of the above. A rubber mainly composed of butyl rubber in a portion where the thermoplastic resin film layer has an air permeability coefficient of 50 · 10 ⁻¹² · cc · cm / cm ² · sec · cmHg or less and does not have the thermoplastic resin film layer A rubber layer joined to the thermoplastic resin film layer is provided, and a tire inner peripheral surface is constituted by the thermoplastic resin film layer and the rubber layer, and a tire width direction of the thermoplastic resin film layer The pneumatic tire according to any one of claims 1 to 3, wherein an inner end is folded and disposed at a split end of the split portion of the carcass layer.

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