JP6208438B2 - Pneumatic safety tire - Google Patents

Description

  The present invention relates to a pneumatic safety tire (hereinafter also simply referred to as “tire”).

  Even if the internal pressure of the tire (hereinafter abbreviated as “internal pressure”) is reduced due to puncture, etc., it is a so-called side-reinforcement type tire that can safely travel a certain distance without losing its load-bearing capacity. Various safety tires have been proposed. A side-reinforced safety tire is a crescent-shaped side reinforcing rubber layer with a relatively high modulus on the inner surface of the carcass on the side wall of the tire to improve the rigidity of the side wall and reduce the side pressure when the internal pressure decreases. A tire having a structure capable of bearing a load without extremely increasing the deformation of the wall portion.

  Moreover, as a rubber reinforced fiber cord used for carcass ply materials of passenger car tires for normal driving at present, the viewpoint that it has high strength per weight and is excellent in dimensional stability, moisture resistance stability, rigidity, cost performance, etc. Therefore, polyester cords such as polyethylene terephthalate (PET) are widely used. Aramid cords are also widely used.

  In general, when a cord made of organic fibers such as PET is used as a tire reinforcing material, the cord is dipped in an adhesive such as a resorcin / formalin / latex (RFL) adhesive, and then the rubber is used. Coat and apply to tire as rubber-cord composite. However, since the surface of polyester fiber such as PET has few reactive sites due to its chemical structure, it is difficult to ensure the adhesive force between the filament and the adhesive in the composite process of cord and rubber. there were. As a technique for further improving the adhesion between PET and rubber, for example, Patent Document 1 discloses a two-bath treatment in which PET is once immersed in an epoxy adhesive and then immersed again in an RFL adhesive. Yes.

JP 2000-355875 A (Claims etc.)

  However, when a side-reinforced safety tire is run at low internal pressure, it is repeatedly compressed between the side-reinforcing rubber and the bead filler rubber arranged on the outer side in the tire radial direction of the bead core as the tire rolls. When the strain is concentrated, the carcass ply cord is fatigued, the strength of the cord is lowered, and it is difficult to travel at a low internal pressure.

  Further, according to the two-bath treatment proposed in Patent Document 1, it is possible to improve the adhesion between PET and rubber. However, when a tire is used under a high load and high temperature environment, stronger adhesion under the input of dynamic strain, particularly heat resistant adhesion, is required between the polyester fiber and the rubber. The establishment of new technology was expected. In addition, when the epoxy adhesive according to the patent document is used, since the processed cord is cured, the cord strength in the tire is likely to be reduced due to the compression input to the carcass ply generated along with the rolling. Was holding. This was the same not only when the polyester fiber was used for the carcass ply cord but also when the aramid fiber was used.

  Accordingly, an object of the present invention is to provide a pneumatic safety tire with improved durability by improving the compression fatigue resistance of the carcass ply cord and improving the heat-resistant adhesion between the carcass ply cord and the rubber. It is in.

That is, the pneumatic safety tire of the present invention has a skeleton of a carcass made of at least one carcass ply extending between a pair of bead cores embedded in a pair of bead portions, and a tire width of a side wall portion of the carcass. It is a pneumatic safety tire with side reinforcing rubber inside in the direction,
In the cross section in the tire width direction, the area of the side reinforcing rubber is S1, the area of the bead filler disposed outside the bead core in the tire radial direction is S2, and the rubber chain disposed outside the bead filler and the bead core in the tire width direction. When the area of the fur is S3, the following formulas (1) and (2),
0.10 ≦ (S2 + S3) /S1≦2.50 (1)
0.3 ≦ S2 / (S2 + S3) ≦ 0.9 (2)
The reinforcing cord of the carcass ply is made of polyester fiber and / or aramid fiber, and an epoxy adhesive containing an epoxy compound is used as a one-bath treatment liquid, and a blocked isocyanate compound and resorcin / formalin latex And the reinforcing cord of the carcass ply is driven at 50/50 mm, the inter-cord distance h ₁ is 2.5 mm, the cord center as the distance _{h 2} to the surface of the rubber is 1.5mm from and embedded in a rubber matrix with two layers as the cord layer are parallel to each other, the width W is 50 mm, the length L is 500mm and A rubber test piece having a height H of 5.5 mm is prepared, and the rubber test piece is hung on a φ50 mm pulley, and the cord shaft The rubber test piece was subjected to a test at room temperature and at a high temperature of 100 ° C. by applying a load of 50 kg / inch in the direction and cyclically applying a tension and a compressive force 300,000 times at 100 rpm. The tensile strength of the cord on the tensile side measured at a pulling speed of 300 mm / min (N / piece) measured after cooling is 12 N / piece or more.

  According to the present invention, a pneumatic safety tire with improved durability can be realized by adopting the above configuration.

(A)-(c) is the width direction one side sectional view which shows an example of the pneumatic safety tire of this invention. It is a partially cutaway perspective view showing still another example of the pneumatic safety tire of the present invention. It is explanatory drawing which shows the generation | occurrence | production state of the turbulent flow by the convex part for turbulent flow generation. It is explanatory drawing which shows the arrangement conditions of the convex part for turbulent flow generation. It is sectional drawing which shows the rubber test piece used for the dynamic adhesion test in an Example. It is a schematic explanatory drawing which shows the dynamic adhesion test method in an Example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1A shows a cross-sectional view in one side in the width direction showing an example of the pneumatic safety tire of the present invention. As shown in the figure, the pneumatic safety tire of the present invention has a carcass 2 including at least one carcass ply extending between a pair of bead cores 1 embedded in a pair of bead portions 11 as a skeleton. The illustrated tire includes two belt layers 3 on the outer side in the radial direction of the crown portion of the carcass 2 and so-called side reinforcing rubber 4 having a substantially crescent-shaped cross section on the inner side in the tire width direction of the sidewall portion 12 of the carcass 2. This is a side-reinforced safety tire.

As shown in the figure, in the tire of the present invention, in the tire width direction cross section, when the area of the side reinforcing rubber 4 is S1, the area of the bead filler 5 is S2, and the area of the rubber chafer 6 is S3, the following formula ( 1) and (2),
0.10 ≦ (S2 + S3) /S1≦2.50 (1)
0 ≦ S2 / (S2 + S3) ≦ 0.9 (2)
The point that satisfies is important. This is due to the following reasons.

  That is, in order to support the vehicle load when the internal pressure of the tire decreases, it is necessary to increase the rigidity of the sidewall portion and the bead portion of the tire. In order to increase the rigidity of the sidewall portion, it is effective to dispose the side reinforcing rubber 4 having a substantially crescent-shaped cross section on the inner side in the tire width direction of the carcass ply in the vicinity of the maximum tire width. In order to increase the rigidity of the bead portion, rubber having a high elastic modulus may be inserted in the vicinity of a portion where the carcass ply 2 and the bead core 1 are adjacent and in the vicinity of a portion where the rim and the tire are in contact with each other. It is effective. At this time, the rigidity of the sidewall portion can be controlled by the area S1 of the side reinforcing rubber 4, and the rigidity of the bead portion is the sum of the area S2 of the bead filler 5 and the area S3 of the rubber chafer 6 (S2 + S3). It can be controlled by

From this viewpoint, as a result of further examination, the present inventor has prescribed the relationship between the area S1 of the side reinforcing rubber 4 and the sum of the areas of the bead filler 5 and the rubber chafer 6 (S2 + S3) according to the above formula (1). Thus, it has been found that a tire capable of supporting the load stably even when the internal pressure is reduced can be obtained by increasing the rigidity of the sidewall portion and the bead portion in a well-balanced manner. If the value of (S2 + S3) / S1 is smaller than 0.10, the relative rigidity of the bead portion decreases, and there is a risk that the tire will fail early in the vicinity of the bead portion. Further, if the value of (S2 + S3) / S1 is greater than 2.50, the deflection of the sidewall portion increases, and there is a risk that the tire will fail early due to rubber breakage due to heat generation. Preferably, the tire of the present invention has the following formula (3),
0.20 ≦ (S2 + S3) /S1≦1.50 (3)
Shall be satisfied. Thereby, tire durability at the time of run flat running can be further improved.

Further, in order to avoid a decrease in cord strength due to repeated compression input to the carcass ply in the vicinity of the bead portion, the area S2 of the bead filler 5 in the sum of the areas of the bead filler 5 and the rubber chafer 6 (S2 + S3) It is necessary that the value of the ratio S2 / (S2 + S3) satisfies the above formula (2). When the value of S2 / (S2 + S3) is larger than 0.9, the compression input to the carcass ply increases along with the deformation of the sidewall portion when the tire is bent under load and the strength of the cord is increased. Decrease increases. On the other hand, the value of S2 / (S2 + S3) may be zero, that is, the bead filler 5 may not be arranged in the present invention. In this case, since the compression input to the code becomes extremely small, it is possible to suppress a decrease in the strength of the code. Preferably, the tire of the present invention has the following formula (4):
0 ≦ S2 / (S2 + S3) ≦ 0.80 (4)
Shall be satisfied. This makes it possible to avoid a decrease in cord strength after running.

  In the tire of the present invention, in the cross section in the tire width direction, the area S1 of the side reinforcing rubber 4, the area S2 of the bead filler 5, and the area S3 of the rubber chafer 6 are the above formulas (1) and (2), preferably further As long as the above formulas (3) and (4) are satisfied, the specific composition of the rubber composition constituting each of the side reinforcing rubber 4, the bead filler 5 and the rubber chafer 6, the physical properties thereof, etc. There is no particular limitation.

  Here, as shown in the figure, the side reinforcing rubber 4 is arranged between the end of the belt 3 and the bead portion 11 beyond the tire maximum width portion between the tire carcass ply 2 and the inner liner (not shown). Established. Moreover, in this invention, the side reinforcement rubber 4 is not limited to when comprised with 1 type of rubber compositions, You may consist of the laminated structure and combined structure of multiple types of rubber | gum substantially. Further, the side reinforcing rubber 4 is not limited to a substantially crescent-shaped cross section as shown. Further, the bead filler 5 is usually between a carcass ply main body portion 2A extending in a toroidal shape between the bead cores 1 and a carcass ply turn-up portion 2B which is folded around the bead core 1 from the inside to the outside. Thus, the bead core 1 is disposed on the outer side in the tire radial direction. Furthermore, the rubber chafer 6 has a lower end portion in the tire radial direction inner side than the outer end in the tire radial direction of the bead core 1 and an upper end portion in a region in a range of 10 to 70% of the tire cross-sectional height. Be placed. Here, the tire cross-sectional height means a height in the tire radial direction in a no-load state when the tire is assembled to an applicable rim and filled with a prescribed air pressure. The standard is an industrial standard that is effective in an area where tires are produced or used, which will be described later.

  In the present invention, the reinforcing cord of the carcass ply 2 is made of polyester fiber and / or aramid fiber. By using polyester fiber cords, aramid fiber cords or hybrid cords of polyester fibers and aramid fibers as the reinforcing cords for the carcass ply 2, these fibers have higher strength and rigidity per weight, so that less cords and rubber Thus, while maintaining the strength of the tire, it is possible to secure the roundness of the tire and obtain an excellent effect in maintaining the tire shape. Specific examples of the polyester fiber include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), and the like. Especially, in this invention, PET, PEN, and an aramid fiber can be used suitably as a reinforcement cord of the carcass ply 2. In particular, since PEN has a rigid molecular structure, tire shape retention can be improved.

  Furthermore, in the present invention, the reinforcing cord of the carcass ply 2 uses an epoxy-based adhesive containing an epoxy compound as a one-bath treatment liquid, and two baths of an adhesive containing a blocked isocyanate compound and resorcin / formalin / latex. It is necessary to be treated with an adhesive using the treatment liquid. Reinforcement cords using polyester fiber or aramid fiber are treated with an epoxy-based adhesive containing an epoxy compound, so that it is easy to adhere to RFL on the surface of polyester cords and aramid cords where it was difficult to ensure adhesion performance with RFL alone Possible epoxy treatment layers can be provided. Further, by subsequently treating with an adhesive containing a blocked isocyanate compound and resorcin / formalin / latex, adhesion between the epoxy-treated layer formed after the treatment and the RFL can be made stronger.

  The treatment with the epoxy-based adhesive containing the epoxy compound is effective for improving the adhesive performance, but also has the disadvantage of being inferior in flexibility of the epoxy material. When applied to the above, since the fatigue resistance of the cord is lowered, sufficient performance cannot be obtained by running the run flat drum. Even when the present inventors use a treatment with an epoxy adhesive containing such an epoxy compound, by applying this to a tire satisfying the relationship of the cross-sectional areas S1 to S3, the adhesion performance and resistance The inventors have found that it is possible to achieve both fatigue and have completed the tire of the present invention.

  The epoxy compound used in the one-bath treatment liquid can achieve the object of the present invention as long as it is a compound containing 2 or more, preferably 4 or more epoxy groups in one molecule. Or a reaction product of a polyhydric alcohol and epichlorohydrin. Specific examples of the epoxy compound include, for example, diethylene glycol diglycidyl ether, polyethylene diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol Reaction of polychloridyl ether, trimethylolpropane / polyglycidyl ether, polyglycerol / polyglycidyl ether, pentaerythiol / polyglycidyl ether, diglycerol / polyglycidyl ether, sorbitol / polyglycidyl ether, and epichlorohydrin Product: Novolak epoxy resin such as phenol novolac epoxy resin and cresol novolac epoxy resin ; Like bisphenol A type epoxy resin. As the epoxy compound, sorbitol polyglycidyl ether or polyglycerol polyglycidyl ether is preferably used. Since these compounds have good water solubility, the use of these compounds as epoxy compounds increases the liquid stability of the adhesive and improves workability. Moreover, since these compounds have good affinity for polyester fibers and aramid fibers, the effect of improving adhesiveness can also be obtained.

（式中、Ａは官能基数３〜５の有機ポリイソシアネート化合物のイソシアネート残基を示し、Ｙは熱処理によりイソシアネート基を遊離するブロック剤化合物の活性水素残基を示し、Ｚは分子中、少なくとも１個の活性水素原子および少なくとも１個のアニオン形成性基を有する化合物の活性水素残基を示し、Ｘは２〜４個の水酸基を有し平均分子量が５０００以下のポリオール化合物の活性水素残基であり、ｎは２〜４の整数であり、ｐ＋ｍは２〜４の整数（ｍ≧０．２５）である。） Moreover, in addition to the said epoxy compound, the blocked isocyanate compound can be mix | blended with the epoxy adhesive used for this invention. As such a blocked isocyanate compound, a compound having a plurality of thermally dissociable blocked isocyanate groups in one molecule is preferably used. For example, a heat-reactive aqueous polyurethane compound represented by the following general formula is optimal.

(In the formula, A represents an isocyanate residue of an organic polyisocyanate compound having 3 to 5 functional groups, Y represents an active hydrogen residue of a blocking agent compound that liberates an isocyanate group by heat treatment, and Z represents at least 1 in the molecule. Represents an active hydrogen residue of a compound having one active hydrogen atom and at least one anion-forming group, X is an active hydrogen residue of a polyol compound having 2 to 4 hydroxyl groups and an average molecular weight of 5000 or less Yes, n is an integer from 2 to 4, and p + m is an integer from 2 to 4 (m ≧ 0.25).)

  The ratio of each component in the one-bath treatment liquid used in the present invention is preferably a dry weight ratio in the adhesive, with the epoxy compound being 30 to 65% and the blocked isocyanate compound being 35 to 70%.

  Next, about the blocked isocyanate compound used for the said 2 bath processing liquid, what blocked organic polyisocyanate compounds, such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI), with the blocking agent is preferable. Examples of the blocking agent include phenols such as phenol, thiophenol, chlorophenol, cresol, resorcinol, p-sec-butylphenol, p-tert-butylphenol, p-sec-amylphenol, p-octylphenol, p-nonylphenol; Secondary or tertiary alcohols such as isopropyl alcohol and tert-butyl alcohol; aromatic secondary amines such as diphenylamine; phthalimides; lactams such as δ-valerolactam; caprolactams such as ε-caprolactam Active methylene compounds such as malonic acid dialkyl ester, acetylacetone and acetoacetic acid alkyl ester; ketoximes such as acetoxime, methylethylketoxime and cyclohexanone oxime; 3-hydroxy Basic nitrogen compounds such as pyridine and acidic sodium sulfite can be raised. Phenol, ε-caprolactam and ketoxime are preferred as the blocking agent.

  The resorcin / formalin / latex preferably comprises a resorcin / formaldehyde resin such as 5-methylresorcin / formaldehyde resin and a latex component. Resorcinol-formaldehyde resin is preferably resorcinol-formaldehyde condensate synthesized under alkali catalyst, or resorcinol-formaldehyde condensate synthesized under alkali catalyst and phenol derivative-formaldehyde condensation synthesized under acidity or neutrality. It consists of a mixture with the product.

  As the latex component, a vinylpyridine / styrene / butadiene copolymer latex can be suitably used. Such vinylpyridine / styrene / butadiene copolymer latex is 5 to 15% by mass of vinylpyridine, 35 to 80% by mass of styrene, and 5 to 60% by mass of butadiene with respect to the total of vinylpyridine, styrene and butadiene. Polymerization was started with a mixed solution containing 5%, and the polymerization was terminated by continuously changing vinylpyridine to 5 to 20% by mass, styrene to 10 to 40% by mass and butadiene to 45 to 75% by mass. It is preferable that it is less affected by volume and modulus changes associated with the cross-linking reaction, and can improve adhesive strength, particularly heat resistance durability.

  The vinylpyridine / styrene / butadiene copolymer can be produced as follows. For example, after dissolving an emulsifier such as potassium rosinate in water, 5-15% by mass, 35-80% by mass, and 5-60% by mass with respect to the total of vinylpyridine, styrene, and butadiene, respectively. Each component is added so that it is contained in a percentage. Further, an electrolyte such as sodium phosphate and peroxides are added as an initiator to perform polymerization. Thereafter, after reaching a predetermined conversion rate, the polymerization is continued by continuously changing vinylpyridine to 5 to 20% by mass, styrene to 10 to 40% by mass and butadiene to 45 to 75% by mass. Thereafter, after reaching a predetermined conversion rate, a reaction terminator is added to stop the polymerization, and further, by removing the remaining monomer, vinyl pyridine styrene styrene having a structure composed of polymers having different composition ratios is obtained. A butadiene copolymer can be obtained.

  In the present invention, examples of vinyl pyridine include 2-vinyl pyridine, 3-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-vinyl pyridine, 5-ethyl-2-vinyl pyridine, and the like. As styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, hydroxymethylstyrene An aromatic vinyl compound such as Furthermore, as butadiene, in addition to 1,3-butadiene, one or more aliphatic conjugated diene monomers such as 2-methyl-1,3-butadiene can be used. Any of these may be used alone or in combination of two or more.

  For the polymerization of the latex, known emulsifiers, polymerization initiators, chain transfer agents and the like may be used. In addition, anti-aging agents such as styrenated phenols and hindered phenols, silicon-based, higher alcohol-based, minerals You may contain additives, such as an oil-type antifoamer, other reaction terminators, and an antifreeze agent.

  The ratio of each component in the two-bath treatment liquid used in the present invention is preferably a dry weight ratio in the adhesive, and 30 to 65% for the blocked isocyanate compound and 35 to 70% for resorcin / formalin / latex.

  In the present invention, the carcass 2 is composed of at least one, for example, 1 to 3, particularly 1 to 2, carcass plies formed by coating a plurality of reinforcing cords arranged in parallel with a coating rubber. In the present invention, when two or more carcass plies 2 are used, the reinforcing cords of all carcass plies 2 are made of polyester fiber or aramid fiber, and are subjected to the above-mentioned specific adhesive treatment. And

  Furthermore, in the present invention, the adhesive strength of the reinforcing cord of the carcass ply 2 is preferably 12 N / line or more, and particularly preferably 15 N / line or more. By setting the adhesive strength of the reinforcing cord of the carcass ply 2 within this range, it is preferable because sufficient durability can be secured against distortion and heat generation due to deflection deformation during run-flat running. Here, the said adhesive force is a value measured by the dynamic adhesion test mentioned later.

  Furthermore, in the present invention, the intermediate elongation at 66N of the carcass ply reinforcement cord in the crown portion taken out from the product tire is 3.5 to 6.6 when the carcass ply reinforcement cord is made of polyester fiber. It is preferably in the range of 5%, particularly 4.5 to 6.0%, and in the case of the reinforcing cord of the carcass ply made of aramid fibers, the range of 0.5 to 2.5%. By setting the intermediate elongation of the reinforcing cord of the carcass ply within this range, it is possible to improve the mileage by suppressing the deflection deformation and heat generation during run-flat travel, and to maintain the tire shape during filling with internal pressure. Excellent effect is obtained.

  Further, in the present invention, the carcass ply 2 is folded around the bead core 1 from the inside to the outside as shown in the drawing. The carcass ply turn-up portion 2B is preferably located closer to the bead core 1 than the maximum thickness portion of the side reinforcing rubber 4 as shown in the figure. This is because the ply cord is less likely to be compressed and deformed, so that fatigue of the ply cord can be suppressed and the tire weight can be reduced.

More preferably, the folded portion 2B of the carcass ply, the height _{H E} from the center of the bead core 1, 30 mm or less, in particular, as being in the range of 5 to 25 mm, for example, shown in FIG. 1 (b) As described above, the height of the folded end portion of the carcass ply 2 is set low. The folded portion 2B of the carcass ply is set low to be positioned bead core 1 side than the maximum thickness of the side reinforcing rubber 4, in particular, when the height H _E and 30mm or less, the rim flange compressed input is applied to the load at Since the organic fiber is not disposed in the vicinity of the contact point between the tire and the tire, it is possible to control the tire performance such as steering stability without considering the fatigue property of the cord. If the carcass ply turn-up portion 2B is too high, compression input acts on the rim flange portion, so the end of the nearby reinforcing cord becomes fatigued, which becomes a fracture nucleus, and induces peeling of the rubber layer, There are cases where the durability of the tire during normal running cannot be sufficiently improved.

In the present invention, the height _{H F} of the bead filler 5, 15 mm or less, it is also particularly preferably from the range of 10 mm. For example, as shown in FIG. 1 (c), the bead filler 5 has a small shape so that the folded portion 2B of the carcass cord immediately follows the inner surface of the tire. When a bending input with the contact point between the rim flange and the tire as a fulcrum is added, the carcass cord exists outside the bending deformation, and only the tensile input, not the compression input, is applied to the cord. . As a result, it is possible to suppress the promotion of the strength reduction of the carcass cord at the folded portion caused by repeated bending deformation, and it is possible to suppress the occurrence of a failure due to the cord breakage. The tire performance can be controlled. As a result, even in a highly rigid carcass cord, it is possible to enjoy the merit of improving the maneuverability while securing the market durability.

  In the present invention, the height of the bead filler 5 is set to 15 mm or less because the shape and the numerical value of the rim flange are standardized. This is because the carcass cord can be avoided. Further, when the bead filler 5 is 15 mm or less in height, there is a possibility that the compression input is applied to the end of the ply depending on the bending rigidity around the bead, the internal pressure condition, input, and the like. By setting the thickness to 10 mm or less, compression input can be reliably avoided regardless of the type of tire. There is no restriction | limiting in particular in the lower limit of the height of the bead filler 5, For example, it can also be set to 0 mm (no bead filler rubber).

  Here, in the present invention, the heights of the carcass ply 2 and the bead filler mean the height in the tire radial direction in a no-load state when the tire is assembled to the applicable rim and filled with a prescribed air pressure. The applicable rim means a rim defined in the following standard, and the prescribed air pressure means an air pressure defined in accordance with the maximum load capacity in the following standard. The standard is an industrial standard effective in an area where tires are produced or used. For example, in the United States, the Tire and Rim Association Inc. In Europe, it is Standards Manual of The European Tire and Rim Technical Organization, and in Japan it is JATMA Year book of Japan Automobile Tire Association.

  The belt layer 3 is composed of a rubberized layer of a cord that extends at an angle of 15 ° to 35 ° with respect to the tire equatorial plane, preferably a rubberized layer of a steel cord, and the two belt layers 3 are usually a belt. The cords constituting the layer 3 are laminated so as to intersect with each other across the equator plane to constitute a belt. In the illustrated example, the belt is composed of two belt layers 3. However, in the tire of the present invention, the number of belt layers constituting the belt is not limited thereto. Furthermore, although not shown in the figure, a belt reinforcing layer (cap layer) covering the entire belt, comprising a rubberized layer of cords arranged substantially parallel to the tire circumferential direction on the outer side in the tire radial direction of the belt 3, A pair of belt reinforcing layers (layer layers) covering only both ends of the cap layer can also be disposed.

  In the tire of the present invention, as shown in FIG. 2, at least a part of the tire surface other than the contact portion with the rim when the rim is mounted on the tire and the tire, preferably as shown in the figure A turbulent-flow generating convex portion 7 may be disposed on the side portion. The provision of the turbulent flow generating convex portion 7 improves the heat dissipation effect from the tire surface, suppresses the temperature rise of the tire during run-flat running, and changes the ambient temperature of the carcass 2 to the fibers constituting the carcass 2. It becomes possible to maintain the cord near the temperature at which the heat shrinkage stress is high. As a result, it is possible to obtain an effect of suppressing the bending during the run-flat running, and it is possible to further improve the emergency running life of the run-flat tire.

  By providing the turbulent flow generating convex portion 7 on the tire surface, the air flow that normally flows on the surface in the tire circumferential direction as the tire rotates is turbulent at the portion where it hits the turbulent flow generating convex portion 7. As a result, the heat flows on the tire surface, whereby positive heat exchange with the tire surface is performed, and the heat radiation of the tire can be promoted. Here, the turbulent flow generation state by the turbulent flow generation convex portion 7 in the present invention will be described with reference to FIG. FIG. 3 is a partial cross-sectional view showing the vicinity of the surface of the run-flat tire of the present invention. As shown in the figure, during the running, the air flow S1 that has been in contact with the tire surface in the portion where the turbulent flow generating convex portion 7 is not formed is generated along with the rotation of the tire. It is peeled off from the tire surface and gets over the turbulent flow generating projection 7. At this time, a portion (region) S <b> 2 where the air flow stays is formed on the back side of the turbulent flow generation convex portion 7. Thereafter, the air flow S1 rebounds on the tire surface between the next turbulent flow generation convex portion 7 and is peeled off from the tire surface again by the next turbulent flow generation convex portion 7. Also at this time, a portion (region) S3 in which the air flow stays is formed on the back side of the next turbulent flow generating projection 7.

  At this time, in order to enhance the heat dissipation effect of the tire, it is advantageous to increase the speed of S1 in the region where the air flow S1 that has become turbulent due to the above contact. From this point of view, in the present invention, as shown in the drawing, a plurality of turbulent flow generating convex portions 7 are arranged in the tire circumferential direction, and these turbulent flow generating convex portions 7 are arranged as turbulent flow generating convex portions. 7, the distance between adjacent turbulent flow generating convex portions 7 at a point at which the width w is divided into two at the center in the longitudinal direction is defined as pitch p, and the height of the turbulent flow generating convex portion 7 is defined as h. Sometimes, it is preferable to arrange so as to satisfy the relationship of 1.0 ≦ p / h ≦ 50.0 and 1.0 ≦ (p−w) /w≦100.0 (see FIGS. 3 and 4). .

  If the value of p / h is less than 1.0, the air flow does not enter the tire surface sandwiched between the adjacent turbulent flow generating projections 7, while if it exceeds 50.0, the influence of turbulence is exerted. In any case, a region that does not reach is generated, and in any case, the heat dissipation efficiency of the portion where the turbulent flow generation convex portion 7 is provided becomes equivalent to the portion where the turbulent flow generating convex portion 7 is not provided. The value of p / h is more preferably 2.0 ≦ p / h ≦ 24.0, and more preferably 10.0 ≦ p / h ≦ 20.0.

  In the present invention, (p−w) / w represents the ratio of the width w of the turbulent flow generation convex portion 7 to the pitch p, and the small value indicates that turbulent flow is generated with respect to the heat radiating surface. It means that the ratio of the area of the convex part 7 for use increases, that is, the area of the heat radiating surface decreases. Therefore, if the value of (p−w) / w is less than 1, the area of the heat radiating surface is too small, and a sufficient improvement effect of the heat radiating efficiency cannot be expected, and further, the volume of rubber increases. There is concern about an increase in the heat generated by rubber. On the other hand, if the value of (p−w) / w exceeds 100.0, the width w becomes too small with respect to the pitch p, and the air flow S1 that collides with the turbulent flow generation convex portion 7 in an inflow collision. However, sufficient rigidity cannot be maintained, and the role as the turbulent flow generating projection 7 may be insufficient. The value of (p−w) / w is preferably 4.0 ≦ (p−w) /w≦39.0.

  Furthermore, in the tire of the present invention, it is preferable that the height h of the turbulent flow generation convex portion 7 satisfies 0.5 mm ≦ h ≦ 7 mm and the width w satisfies 0.3 mm ≦ w ≦ 4 mm. When the height h exceeds 7 mm and the width w exceeds 4 mm, the volume of the turbulent flow generation convex portion 7 increases, heat generation at the turbulent flow generation convex portion 7 increases, and turbulent flow generation occurs. There is a risk that the area where the convex portion 7 covers the surface increases and heat is stored on the rubber surface. Further, when h is less than 0.5 mm and w is less than 0.3 mm, the necessary rigidity as the turbulent flow generating convex portion 7 cannot be maintained as described above, and therefore the heat dissipation effect is obtained. There is a risk that it may not be obtained sufficiently.

  Further, as schematically shown in FIG. 4, in the tire of the present invention, the turbulent flow generation convex portion 7 is arranged such that an angle θ between the longitudinal direction a and the tire radial direction r is 70 ° or less. It is preferable that The air flow on the tire surface on which the turbulent flow generation convex portion 7 is disposed is slightly outward in the tire radial direction due to the centrifugal force generated by the rotation of the tire. Therefore, the angle θ formed by the longitudinal direction a of the turbulent flow generation convex portion 7 with respect to the tire radial direction r is set to 70 ° or less, so that air flows into the tire surface and the rear of the turbulent flow generation convex portion 7 Therefore, the heat retention efficiency can be improved by reducing the staying portions S2 and S3. The longitudinal direction “a” of the turbulent flow generation convex portion 7 may be in a range of a total of 140 ° including 70 ° on one side and 70 ° on the other side with reference to the tire radial direction r.

  In this case, on the surface of the rotating tire, the air flow velocity varies depending on the position in the tire radial direction r. Therefore, when a plurality of turbulent flow generating convex portions 7 are arranged in the tire radial direction, the angle θ is set according to the position of the turbulent flow generating convex portion 7 in the tire radial direction. It is preferable to make it different for every seven.

  In the present invention, the shape of the turbulent flow generating convex portion 7 is not particularly limited, but preferably, as shown in the drawing, the turbulent flow generating convex portion 7 is at least at the inner side in the tire radial direction, the top portion 7A. It shall have. In other words, as shown in FIG. 2, the turbulent flow generation convex portion 7 may have a shape in which the portion corresponding to the top portion 7A is a curved surface in addition to the shape having the four top portions 7A. However, by having the top portion 7A at least inward in the tire radial direction, a three-dimensional air flow is generated around the top portion 7A, and the heat dissipation effect is further improved.

  In the present invention, it is also preferable that the turbulent flow generation convex portion 7 is divided in the longitudinal direction. If the turbulent flow generating projections 7 are divided in the longitudinal direction, the stagnation flow generating projections S2 and S3 generated behind the turbulent flow generating projections 7 during tire rotation are reduced. Average heat dissipation can be achieved over the entire portion where the portion 7 is provided. In addition, the division | segmentation number of the convex part 7 for turbulent flow generation in this case is not specifically limited, It can select arbitrarily.

  Further, in the tire of the present invention, when a plurality of turbulent flow generating convex portions 7 are arranged in the tire circumferential direction and the radial direction, the installation frequency of the turbulent flow generating convex portions 7 in the tire circumferential direction is set. However, it is preferable that the position varies depending on the position in the tire radial direction. On the surface of the rotating tire, the flow velocity of air varies depending on the position in the radial direction. Moreover, the heat dissipation efficiency depends on the flow velocity of air flowing on the tire surface. Accordingly, a plurality of turbulent flow generating convex portions 7 are installed in the tire circumferential direction and in the radial direction, respectively, and the installation frequency of the turbulent flow generating convex portions 7 in the tire circumferential direction, that is, the number of installation is changed depending on the tire radial direction. Thus, the non-uniformity of the heat dissipation efficiency due to the difference in the position in the tire radial direction on the tire surface can be eliminated.

  Further, for example, in the tire of the present invention, a tread pattern is appropriately formed on the surface of the tread portion 13, and an inner liner (not shown) is formed in the innermost layer. Furthermore, in the tire of the present invention, as the gas filled in the tire, normal or air with a changed oxygen partial pressure, or an inert gas such as nitrogen can be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
The twist and twist of two 1670 dtex yarn converging bodies, which are multifilaments of polyethylene terephthalate (PET), are twisted together at a twist number of 39 times per 10 cm in length to obtain 1670 dtex / 2, a twist number of 39 × 39 (times A PET cord having a structure represented by / 10 cm) was obtained. Similarly, a cord having a structure represented by 1670 dtex / 2 of polyethylene naphthalate (PEN, raw yarn type No. Q904 (manufactured by Teijin Limited)), twist number 39 × 39 (times / 10 cm), and poly Cords having a structure represented by 1670 dtex / 2 and a twist number of 39 × 39 (times / 10 cm) of paraphenylene terephthalamide (aramid, Kevler (manufactured by Toray DuPont)) were prepared.

  Adhesive compositions of Examples, Reference Examples and Comparative Examples were prepared with the formulations shown in the following table, and an epoxy adhesive containing 5% by mass of the adhesive composition was prepared. After the epoxy adhesive was attached to the twisted cord, it was dried at 180 ° C. for 1 minute using a heat treatment machine.

＊１）下記表４，５参照。
＊２）ブロックドイソシアネート化合物（第一工業製薬（株）製、「エラストロンＢＮ２７」、固形分濃度３０％、メチレンジフェニルの分子構造を含むブロックドイソシアネート化合物）

* 1) See Tables 4 and 5 below.
* 2) Blocked Isocyanate Compound (Daily Kogyo Seiyaku Co., Ltd., “Elastolon BN27”, solid content concentration 30%, blocked isocyanate compound containing methylenediphenyl molecular structure)

  Next, an RFL + U-based adhesive containing 20% by mass of the adhesive composition shown in the following table was prepared. After the RFL + U adhesive was attached to the cord after the treatment with the epoxy adhesive, it was dried at 180 ° C. for 1 minute using a heat treatment machine. The obtained cord was heat-treated at 240 ° C. for 2 minutes under a tension (cord tension) of 1 to 2 kg / tube to produce a tire cord to which an adhesive was adhered.

＊３）ビニルピリジン・スチレン・ブタジエン共重合ラテックス（日本ゼオン（株）製、「Ｎｉｐｏｌ２５１８ＦＳ」、固形分４０．５質量％）

* 3) Vinylpyridine / styrene / butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd., “Nipol 2518FS”, solid content 40.5 mass%)

  In addition, the mixing | blending of the conventional RFL type adhesive composition as an RFL type adhesive agent used by the comparative example is as showing in the following table | surface.

(Dynamic adhesion test)
FIG. 5 is a perspective view showing a rubber test piece used in the dynamic adhesion test.
As shown in the figure, the tire reinforcing polyester cords 22 of the examples, reference examples and comparative examples are embedded in a rubber matrix so that the cord layers are parallel to each other, and the width W is 50 mm and the length L is 500 mm. And each rubber test piece 21 was produced by height H: 5.5mm. The number of cords to be driven was 50/50 mm, the distance h ₁ between cords was 2.5 mm, and the distance h ₂ from the cord center to the surface was 1.5 mm. As shown in FIG. 6, the obtained rubber test pieces 21 were hung on a pulley 23 (φ50 mm), a load of 50 kg / inch was applied in the cord axis direction, and tension and compressive force were cyclically repeated 300,000 times at 100 rpm. Loaded. The above test was carried out in a thermostatic chamber capable of keeping the atmospheric temperature constant, and the dynamic adhesion at room temperature and at a high temperature of 100 ° C. was tested. After the test, the sample was cooled and then the tensile strength of the cord on the tensile side was measured (N / piece) to determine the dynamic adhesive strength. Here, the rubber matrix used for the sample preparation was natural rubber 60.0 parts by mass, styrene butadiene rubber (SBR) 40.0 parts by mass, carbon black (HAF) 45.0 parts by mass, softener (spindle oil) 2 0.0 parts by weight, 3.0 parts by weight of zinc white, 1.0 part by weight of an anti-aging agent (NOCRACK 6C, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), a vulcanization accelerator (Noxeller NS, Ouchi Shinsei Chemical Industry ( Co., Ltd.) 0.8 parts by mass, 1.0 parts by mass of stearic acid and 3.0 parts by mass of sulfur. The pulling speed during the adhesion test was 300 mm / min. The rubber test piece was produced under vulcanization conditions of 160 ° C. × 20 minutes.

  Using the resulting rubber-cord composite, a treat with 50 shots / 50 mm was produced and applied to a carcass ply to produce a pneumatic safety tire with a tire size of 225 / 45R17.

  This test tire has a carcass made of a single carcass ply extending between a pair of bead cores embedded in a pair of bead portions, and the outer side in the tire radial direction of the carcass is ± The belt had two layers of belts (material: steel) that were arranged to intersect each other at an angle of 40 °, and one layer layer (material: nylon) covering the entire width of the belt layer. In addition, side reinforcement rubber is provided on the inner side in the tire width direction of the sidewall portion of the carcass, a bead filler is disposed on the outer side in the tire radial direction of the bead core, and a rubber chafer is disposed on the outer side in the tire width direction of the bead filler and the bead core. It had been. Each example, reference example and comparative example are adjusted so that the area S1 of the side reinforcing rubber, the area S2 of the bead filler, and the area S3 of the rubber chafer in the tire width direction cross section satisfy the conditions shown in the following table. A test tire was prepared. In addition, about the comparative example 5 and the reference examples 1-3, the bead filler was not provided.

(Drum durability test)
Each test tire was assembled on a standard rim specified by JATMA, then attached to a drum testing machine, filled with an internal pressure of 100 kPa, loaded with a maximum load specified by JATMA, and run on the drum for 20000 km. After completion of the test, each test tire was dissected and the residual strength of the carcass ply was measured, and the strength retention rate from the new article was evaluated. The result is expressed as an index when the strength retention of Comparative Example 1 is set to 100, and the larger the value, the better the drum durability. The results are also shown in the table below.

＊４）エポキシ化合物Ａ：ソルビトールポリグリシジルエーテル（「デナコールＥＸ６１４Ｂ」、水性樹脂），エポキシ化合物Ｂ：ポリグリセロールポリグリシジルエーテル（「デナコールＥＸ５１２」、水性樹脂），エポキシ化合物Ｃ：ポリグリセロールポリグリシジルエーテル（「デナコールＥＸ５２１」、水性樹脂）（いずれもナガセケムテックス（株）製）
＊５）Ａ：カーカスプライの折返し部の、ビードコアの中心からの高さＨ_Ｅが、６０ｍｍである構造。Ｂ：カーカスプライの折返し部の、ビードコアの中心からの高さＨ_Ｅが、３０ｍｍである構造。Ｃ：カーカスプライの折返し部の、ビードコアの中心からの高さＨ_Ｅが、１５ｍｍである構造。

* 4) Epoxy compound A: sorbitol polyglycidyl ether (“Denacol EX614B”, aqueous resin), epoxy compound B: polyglycerol polyglycidyl ether (“Denacol EX512”, aqueous resin), epoxy compound C: polyglycerol polyglycidyl ether ( “Denacol EX521”, water-based resin) (all manufactured by Nagase ChemteX Corporation)
* 5) A: the turnup portion of the carcass ply, the height _{H E} from the center of the bead core is 60mm structure. B: the folded portion of the carcass ply, the height _{H E} from the center of the bead core is 30mm structure. C: the folded portion of the carcass ply, the height _{H E} from the center of the bead core is 15mm structure.

  As shown in the table above, polyester fiber or aramid fiber is used for the carcass ply reinforcement cord, and a predetermined adhesion treatment is performed, and the area of the side reinforcement rubber, bead filler, and rubber chafer in the cross section of the tire width direction is determined. In the test tires of the examples and reference examples in which the ratio is set so as to satisfy the predetermined relationship defined by the formulas (1) and (2), compared with the test tires of the comparative examples that do not satisfy the above relationship. As a result, it was confirmed that the adhesive strength and the drum durability were improved as a whole.

1 bead core, 2 carcass, 3 belt layer, 4 side reinforcement rubber, 5 bead filler, 6 rubber chafer, 7 convex part for turbulent flow generation, 7A top, 11 bead part, 12 side wall part, 13 tread part

Claims (6)

A pneumatic safety comprising a carcass made of at least one carcass ply extending between a pair of bead cores embedded in a pair of bead portions, and having side reinforcing rubber on the inner side in the tire width direction of the side wall portion of the carcass Tire,
In the cross section in the tire width direction, the area of the side reinforcing rubber is S1, the area of the bead filler disposed outside the bead core in the tire radial direction is S2, and the rubber chain disposed outside the bead filler and the bead core in the tire width direction. When the area of the fur is S3, the following formulas (1) and (2),
0.10 ≦ (S2 + S3) /S1≦2.50 (1)
0.3 ≦ S2 / (S2 + S3) ≦ 0.9 (2)
Satisfied, the reinforcing cord before Symbol carcass ply, together with a polyester fiber and / or aramid fibers, with an epoxy-based adhesive containing an epoxy compound as a bath treatment solution, blocked isocyanate compound and resorcin-formalin an adhesive comprising a latex Ri name is treated adhesive used as a two-bath treatment liquid, and the reinforcing cords of the carcass ply at implantation number 50 present / 50 mm, the inter-cord distance h ₁ is 2.5 mm, The cord layer is embedded in the rubber matrix in two layers so that the distance h ₂ from the cord center to the rubber surface is 1.5 mm, and the width W is 50 mm and the length L is A rubber test piece having a length of 500 mm and a height H of 5.5 mm was prepared, and the rubber test piece was hung on a pulley of φ50 mm, and the cord shaft The rubber test piece was subjected to a test at room temperature and at a high temperature of 100 ° C. by applying a load of 50 kg / inch in the direction and cyclically applying a tension and a compressive force 300,000 times at 100 rpm. A pneumatic safety tire characterized by having a tensile-side-cord adhesion force (N / piece) of 12 N / piece or more, measured after cooling, at a tensile speed of 300 mm / min . The following formulas (3) and (4),
0.20 ≦ (S2 + S3) /S1≦1.50 (3)
0.3 ≦ S2 / (S2 + S3) ≦ 0.80 (4)
The pneumatic safety tire according to claim 1, wherein: The pneumatic safety tire according to claim 1 or 2, wherein a height of the bead filler is 15 mm or less. Said carcass ply, facing folded will be outward from the tire inner side around the bead cores, the folded ends of the carcass ply, one of claims 1 to 3 positioned below a height of 30mm from the center of the bead core The pneumatic safety tire according to any one of the above. The pneumatic safety tire according to any one of claims 1 to 4 , wherein the epoxy compound is sorbitol polyglycidyl ether or polyglycerol polyglycidyl ether. The pneumatic safety tire according to any one of claims 1 to 5 , wherein the polyester fiber is a polyethylene naphthalate fiber.

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