JP2014166832A - Pneumatic safety tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic safety tire having improved durability by enhancing compression fatigue characteristics of a carcass ply cord.SOLUTION: A pneumatic safety tire has a carcass 2 extending between a pair of bead cores 1 when the bead cores are respectively buried in a pair of bead parts 11, and being made of at least one sheet of a carcass ply as a frame. A side reinforcement rubber 4 is provided inside of a tire width direction of a sidewall portion and a rubber chafer is arranged outside of the tire width direction of the carcass and the bead cores in the pneumatic safety tire. When area of the side reinforcement rubber is S1, and area of a rubber chafer is S2, a following formula is satisfied in a tire width direction cross section: (1) 0.10≤S2/S1≤2.50. A reinforcement cord of the carcass ply is made of a polyester fiber and/or an aramid fiber.

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-reinforcing type safety tire is run at a low internal pressure, the side reinforcing rubber and a rubber member disposed on the outer side in the tire width direction with the carcass ply interposed therebetween as the tire rolls. When the compressive strain is repeatedly 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, leading to an early failure.

  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 Patent Document 1 is used, the treated cord is cured, so that the cord strength in the tire tends to decrease due to the compression input to the carcass ply generated along with the rolling. I had a problem. 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.

  Therefore, an object of the present invention is to provide a pneumatic safety tire with improved durability by improving the compression fatigue property of the carcass ply cord.

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. In a pneumatic safety tire comprising a side reinforcing rubber on the inner side in the direction, and a rubber chafer disposed on the outer side in the tire width direction of the carcass and the bead core,
In the tire width direction cross section, when the area of the side reinforcing rubber is S1, and the area of the rubber chafer is S2, the following formula (1),
0.10 ≦ S2 / S1 ≦ 2.50 (1)
And the reinforcing cord of the carcass ply is made of polyester fiber and / or aramid fiber.

  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.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1A to 1C are cross-sectional views 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, the carcass ply 2 is sandwiched and locked by the divided bead core 1 ((a) in the figure), or around the bead core 1 from the inside to the outside. (B) and (c) in the figure. Of these, (b) in the figure shows a structure in which the folded carcass ply 2 is wound around the bead core 1 and its end is wound along the bead core 1, and (c) in the figure is folded. 1 shows a structure in which the end of the carcass ply 2 is wound around the bead core 1 and then the end is rolled up along the main body of the carcass ply 2 extending between the bead cores 1. That is, in the tire of the present invention, no bead filler having a tapered cross section is disposed outside the bead core 1 in the tire radial direction, and instead of the bead filler, rubber is disposed outside the carcass 2 and the bead core 1 in the tire width direction. A chafer 5 is arranged. By not using the bead filler, the compression input to the carcass ply in the vicinity of the bead portion becomes extremely small, so the decrease in cord strength due to repeated compression input can be suppressed to a very low level, resulting in tire durability. Can be improved. In the tire of the present invention, as long as a rubber chafer is disposed instead of the bead filler, the locking structure of the end portion of the carcass ply 2 is not limited to the illustrated example.

As shown in the figure, in the tire of the present invention, when the area of the side reinforcing rubber 4 is S1 and the area of the rubber chafer 5 is S2 in the tire width direction cross section, the following formula (1),
0.10 ≦ S2 / S1 ≦ 2.50 (1)
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, in the structure of the present invention, it is considered that 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 can be controlled by the area S2 of the rubber chafer 5.

From this point of view, as a result of further examination, the present inventor defines the relationship between the area S1 of the side reinforcing rubber 4 and the area S2 of the rubber chafer 5 according to the above formula (1). 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 portion in a well-balanced manner. If the value of S2 / S1 is smaller than 0.10, the relative rigidity of the bead portion is lowered, and there is a possibility that the tire may fail early in the vicinity of the bead portion. Further, if the value of S2 / S1 is greater than 2.50, the deflection of the sidewall portion increases, and the tire may break down early due to rubber breakage due to heat generation. Preferably, the tire of the present invention has the following formula (2),
0.20 ≦ S2 / S1 ≦ 2.0 (2)
More preferably, the following formula (3),
0.50 ≦ S2 / S1 ≦ 1.5 (3)
Shall be satisfied. Thereby, tire durability at the time of run flat running can be further improved.

  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 and the area S2 of the rubber chafer 5 are the above formula (1), preferably further the above formula (2), more preferably There is no particular limitation on the specific composition and physical properties of the rubber composition constituting each of the side reinforcing rubber 4 and the rubber chafer 5 as long as the above formula (3) is satisfied.

  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 rubber chafer 5 is arranged in a region where the lower end portion is inside the tire radial direction from the outer end in the tire radial direction of the bead core 1 and the upper end portion is located in a range of 10 to 70% of the tire cross-section height. Is done. 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.

  In the present invention, it is preferable that the reinforcing cord of the carcass ply 2 is treated with a pretreatment liquid or an adhesive liquid containing an epoxy compound. Reinforcement cords using polyester fiber and aramid fiber are treated with a pretreatment liquid or adhesive liquid containing an epoxy compound to improve the adhesion between rubber and reinforcement cords and improve tire durability. Can contribute, which is preferable. Among these, as the pretreatment liquid containing the epoxy compound used in the present invention, those containing an epoxy compound which is one kind or a mixture of two or more kinds of epoxy compounds having two or more epoxy groups in one molecule are suitable. is there. More specifically, halogen-containing epoxies are preferred, and examples include those obtained by synthesis with epichlorohydrin polyhydric alcohols or polyhydric phenols, and compounds such as glycerol polyglycidyl ether are preferred. The adhesion amount of the pretreatment liquid containing such an epoxy compound to the fiber surface is in the range of 0.05 to 1.5 mass%, preferably 0.10 to 1.0 mass%. You may mix a smoothing agent, an emulsifier, an antistatic agent, another additive, etc. with a pre-processing liquid as needed. Such a pretreatment liquid can be used by adhering to the surface of polyester fiber or aramid fiber.

  Specifically, the adhesive liquid containing an epoxy compound used in the present invention contains, as an epoxy compound, a compound containing 2 or more, preferably 4 or more epoxy groups in one molecule, preferably containing an epoxy group. It is preferable to contain a compound 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 Polyglycidyl ether, diglycerol / triglycidyl ether, trimethylolpropane / polyglycidyl ether, polyglycerol / polyglycidyl ether, pentaerythiol / polyglycidyl ether, diglycerol / polyglycidyl ether, sorbitol / polyglycidyl ether, etc. Reaction products of monohydric alcohols and epichlorohydrin; phenol novolac type epoxy resin, cresol novolac type Novolak epoxy resins such as epoxy resins; bisphenol A type epoxy resins.

  In addition to the epoxy compound, the adhesive solution containing the epoxy compound can be blended with various blending components used for epoxy adhesives in the industry.

  More preferably, 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 2 adhesives containing a blocked isocyanate compound and resorcin / formalin / latex. It shall be an adhesive treatment using the bath 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.

  Examples of the epoxy compound used in the one-bath treatment liquid include those listed above. Since the above compounds have good water solubility, the use of these compounds as epoxy compounds increases the liquid stability of the adhesive and improves the 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-type adhesive agent as said 1 bath processing liquid. 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%.

  Moreover, 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 the carcass plies 2 are made of polyester fibers or aramid fibers.

  In the present invention, as shown in FIG. 1C, when the end portion of the carcass ply 2 is wound up along the main body portion of the carcass ply 2 extending between the bead cores 1, The folded end 2a of the ply is preferably positioned closer to the bead core 1 than the maximum thickness of the side reinforcing rubber 4 as shown in the figure. This is because the tire weight is reduced.

More preferably, the folded portion 2a 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, high of turnup ends of the carcass ply 2 Set the height low. The carcass ply turn-up portion 2a is set so as to be positioned closer to the bead core 1 than the maximum thickness portion of the side reinforcing rubber 4, and particularly when the height _HE is 30 mm or less, a rim flange to which compression input is applied during loading 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 2a 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, inducing peeling of the rubber layer, There are cases where the durability of the tire during normal running cannot be sufficiently improved.

  Here, in the present invention, the height of the carcass ply 2 means the 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 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 generating projection 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 count of 40 times per 10 cm in length to obtain 1670 dtex / 2, a twist number of 40 × 40 (times A PET cord having a structure represented by / 10 cm) was obtained. This polyester twisted cord is immersed in an adhesive containing no epoxy compound (see Table 1 below) or an adhesive containing an epoxy compound (see Table 2 below) as an adhesive treatment, and 2 in a 160 ° C. trizone. Heat treatment was performed for 120 seconds under a tension of 2.0 kg / line for 60 seconds under a tension of 0.0 kg / line and for 60 seconds under a tension of 2.0 kg / line in a 240 ° C hot zone. Processing was performed using a latex (RFL) adhesive (see Table 3 below) to prepare a cord coated with the adhesive. The tension of the last hot zone in the dipping process was finely adjusted so that the intermediate elongation at 66 N load of the cord was 4.3%.

<Preparation of an adhesive containing no epoxy compound>
First, a mixed solution of soft water, resorcin, 37% formaldehyde aqueous solution and vinylpyridine latex was aged at 25 ° C. for 24 hours to prepare an RFL solution. Next, resorcinol formaldehyde novolak type condensate and aqueous caustic soda solution were mixed with the RFL solution to prepare an adhesive having the composition shown in Table 1 below.

＊１）ナガセケムテックス（株）製

* 1) Made by Nagase ChemteX Corporation

<Preparation of resorcin / formalin / latex (RFL) adhesive>
An RFL adhesive containing 20% by mass of the adhesive composition shown in the following table was prepared. The RFL-based adhesive was attached to the cord that had been treated with the adhesive not containing the epoxy compound or the adhesive containing the epoxy compound, and then 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.

＊２）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）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）

* 2) Vinylpyridine / styrene / butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd., “Nipol 2518FS”, solid content 40.5 mass%)
* 3) Blocked isocyanate compound (made by Daiichi Kogyo Seiyaku Co., Ltd., “Elastolon BN27”, solid content concentration 30%, blocked isocyanate compound containing methylenediphenyl molecular structure)

  The obtained polyester cord was covered with rubber to obtain a rubber-cord composite. Moreover, about the code | cord | chord of the structure represented by 1670 dtex / 2 of the polyparaphenylene terephthalamide (Aramid, Kevler (Kevlar) (made by Toray DuPont Co., Ltd.)) and the twist number 39 * 39 (times / 10cm), and the above In the same manner, the adhesive treatment was performed, and the rubber was coated with rubber to obtain a rubber-cord composite.

  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 ± It had two layers of belts (material: steel) that were interlaced with each other at an angle of 40 °. Further, side reinforcing rubber is provided on the inner side in the tire width direction of the sidewall portion of the carcass, and a rubber chafer is disposed on the outer side in the tire width direction of the carcass ply and the bead core. The tires of the respective examples and comparative examples were prepared by adjusting the side reinforcing rubber area S1 and the rubber chafer area S2 in the tire width direction cross section to satisfy the conditions shown in the following table.

(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.

  As shown in the above table, polyester fiber or aramid fiber is used for the carcass ply reinforcement cord, and the area ratio of the side reinforcement rubber and the rubber chafer in the cross section in the tire width direction is defined by equation (1). It was confirmed that the drum durability was improved in the test tires of each example set so as to satisfy the predetermined relationship as compared with the test tires of comparative examples not satisfying the above relationship.

1 bead core, 2 carcass, 3 belt layer, 4 side reinforcement rubber, 5 rubber chafer, 7 turbulent flow generating projection, 7A top, 11 bead, 12 sidewall, 13 tread

Claims (5)

A carcass made of at least one carcass ply extending between a pair of bead cores embedded in a pair of bead parts, and having a side reinforcing rubber on the inner side in the tire width direction of the side wall part of the carcass, And a pneumatic safety tire in which a rubber chafer is disposed on the outer side in the tire width direction of the bead core,
In the tire width direction cross section, when the area of the side reinforcing rubber is S1, and the area of the rubber chafer is S2, the following formula (1),
0.10 ≦ S2 / S1 ≦ 2.50 (1)
And a reinforcing cord for the carcass ply is made of polyester fiber and / or aramid fiber.   2. The pneumatic safety tire according to claim 1, wherein the carcass ply is folded and wound around the bead core from the inside to the outside, or is sandwiched and locked by the divided bead core. . Following formula (2),
0.20 ≦ S2 / S1 ≦ 2.0 (2)
The pneumatic safety tire according to claim 1 or 2, satisfying   The pneumatic safety tire according to any one of claims 1 to 3, wherein the reinforcing cord of the carcass ply is treated with a pretreatment liquid or an adhesive liquid containing an epoxy compound.   The carcass ply reinforcing cord uses an epoxy-based adhesive containing an epoxy compound as a one-bath treatment liquid, and an adhesive treatment using a blocked isocyanate compound and resorcin / formalin / latex as a two-bath treatment liquid. The pneumatic safety tire according to claim 4 which is made.

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