JP2019199198A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire comprising a treat member that can improve durability and the like of the tire.SOLUTION: A pneumatic tire 10 comprises a tread part 1, a side wall part 2, bead parts 3, a carcass 4 constituted of at least one carcass ply toroidally extending across the bead parts 3, and a belt 5 constituted of at least two belt layers 5a and 5b arranged outside in a tire radial direction of the carcass 4. A treat member 20, formed by coating a bundle cord 23 formed by bundling totally three or more of a metal cord 21 and non-metal cords 22, with coating rubber 24, is used in the carcass and/or at least one belt layer. At least an end at one end of the bundle cord 23 is the non-metal cord 22, and a volume ratio of the metal cord 21 to the non-metal cord 22 in the bundle cord 23 is 5:95-95:5.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire (hereinafter, also simply referred to as “tire”), and more particularly, to a pneumatic tire including a treating member that can improve the durability and the like of the tire.

  In general, a belt, which is a carcass reinforcing member that forms the framework of a pneumatic tire, is mainly composed of a steel belt layer that is a rubberized layer of a steel cord that is inclined with respect to the equator plane of the tire. As described above, the steel cords are arranged so as to cross each other. However, since the belt layer made of steel cord works to increase the weight, it has a trade-off relationship with fuel efficiency. Under such circumstances, a technique for replacing the steel cord of the steel belt layer with an organic fiber cord has been proposed to reduce the weight of the tire.

  For example, Patent Document 1 proposes a corded rubber sheet (treat) in which a large number of steel cords and organic fiber cords are arranged in parallel at intervals, and these cords are covered with a rubber material. The corded rubber sheet is used as a constituent material for a tire belt layer, a carcass ply, and the like, thereby improving the running performance and athletic performance of the tire and realizing low fuel consumption by reducing the weight.

Japanese Patent Laid-Open No. 08-72160

  However, in recent years, the performance required for tires has become increasingly sophisticated, and even if the corded rubber sheet proposed in Patent Document 1 is applied to a carcass ply or a belt layer, it may not always be satisfactory. There is a current situation that further improvement is desired.

  Therefore, an object of the present invention is to provide a pneumatic tire provided with a treating member that can improve the durability and the like of the tire.

  As a result of intensive studies to solve the above problems, the present inventor used a bundle cord formed by bundling a total of three or more of a metal cord and a non-metal cord, and further, at least one end of the bundle cord. It has been found that the above problem can be solved by arranging the non-metallic cord, and the present invention has been completed.

That is, the pneumatic tire of the present invention includes a tread portion, a sidewall portion, a bead portion, a carcass composed of at least one carcass ply extending between the bead portions, and a carcass ply of the carcass. In a pneumatic tire provided with a belt comprising at least two belt layers disposed on the outer side in the tire radial direction,
A treat member is used in which a bundle cord formed by bundling a total of three or more metal cords and non-metal cords is covered with a coating rubber,
At least one end of the bundle cord is a non-metallic cord, and
The volume ratio of the metal cord to the non-metal cord in the bundle cord is 5:95 to 95: 5.

  In the tire of the present invention, it is preferable that a mass ratio of the metal cord to the non-metal cord in the treat member is 5:95 to 95: 5. Moreover, in the tire of this invention, it is preferable that the diameter ratio of the said metal cord and the said nonmetallic cord in the said treat member is 20: 80-95: 5. In particular, in the tire of the present invention, the treat member is suitable for at least one belt layer.

  ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire provided with the treat member which can improve the durability etc. of a tire can be provided. In particular, by using the treating member as a belt layer, the weight of the tire can be reduced, and rolling resistance, steering stability and durability can be improved.

1 is a schematic cross-sectional view in the tire width direction of a pneumatic tire according to a preferred embodiment of the present invention. It is a width direction sectional view of a treating member used for a pneumatic tire concerning one suitable embodiment of the present invention.

  Hereinafter, the pneumatic tire of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view in the tire width direction of a pneumatic tire according to a preferred embodiment of the present invention. The illustrated pneumatic tire 10 includes a tread portion 1 that forms a ground contact portion, and the tread portion. 1 is provided with a pair of sidewall portions 2 continuously extending inward in the tire radial direction and bead portions 3 continuing on the inner peripheral side of each sidewall portion 2. In the illustrated tire 10, the tread portion 1, the sidewall portion 2, and the bead portion 3 are reinforced by a carcass 4 including a single carcass ply extending in a toroid shape from one bead portion 3 to the other bead portion 3. However, in the tire 10 of the present invention, the carcass 4 may be composed of a plurality of carcass plies.

  In the tire 10 of the present invention, at least two belt layers disposed on the outer side in the tire radial direction of the carcass 4, and in the illustrated example, a belt 5 comprising two layers of a first belt layer 5a and a second belt layer 5b. In the tire 10 of the present invention, the belt layer may be three or more layers. In the illustrated tire 10, a belt reinforcing layer 6 is disposed on the outer side in the tire radial direction of the belt 5. The belt reinforcing layer 6 may be one or both of a cap layer 6 a disposed over the entire width of the belt 5 and a layer layer 6 b disposed in both end regions of the belt 5.

  FIG. 2 is a cross-sectional view in the width direction of a treat member used in a pneumatic tire according to a preferred embodiment of the present invention. The tire 10 of the present invention is formed by bundling a total of three or more metal cords 21 and non-metal cords 22, in the illustrated example, two metal cords 21 and two non-metal cords 22 in total. The treat member 20 in which the bundle cord 23 is covered with the covering rubber 24 is used as, for example, a carcass ply, belt layers 5a and 5b, and preferably as belt layers 5a and 5b. Here, the metal cord 21 and the non-metallic cord 22 in the bundle cord 23 are arranged and aligned in the width direction of the treat member 20. Since the tire 10 of the present invention uses the treat member 20 composed of the metal cord 21 and the non-metal cord 22, the weight can be reduced as compared with the case where the treat member composed of only the metal cord is used. , Leading to a reduction in rolling resistance. Further, the in-plane rigidity of the treat member 20 is increased by bundling the metal cord 21 and the non-metallic cord 22. Therefore, when the treat member 20 according to the present invention is used for the belt layers 5a and 5b, the steering stability can be improved.

  Further, in the tire 10 of the present invention, the treating member 20 is a non-metallic cord 22 at least one end, preferably both ends, of the bundle cord 23. By adopting such a configuration, the rigidity step between the covering rubber 24 and the bundle cord 23 can be reduced as compared with the case where only a bundle of metal cords is used, and the durability of the treat member 20 is improved. As a result, the durability of the tire 10 can be improved. For example, by using the treat member 20 according to the present invention for the belt layers 5a and 5b, the belt edge separation (BES) in which the peeling of rubber starting from the cord end of the belt width direction end portion propagates between adjacent cords is suppressed. can do. Further, when used for a carcass ply, ply end separation starting from the end of the carcass ply can be suppressed.

  Moreover, in the tire of this invention, the volume ratio of the metal cord 21 and the nonmetallic cord 22 in the bundle cord 23 is 5:95 to 95: 5. By setting it as this range, the effect of this invention can be acquired favorably. If at least one end of the bundle cord 23 is a non-metallic cord 22, the arrangement of the metal cord 21 and the non-metallic cord 22 in the bundle cord 23 is not particularly limited. For example, the metallic cord 21 and the non-metallic cord 22 may be alternately arranged, and in the bundle cord 23, there may be a portion where the metal cord 21 continues or a portion where the non-metal cord 22 continues. In the tire 10 of the present invention, the number of the metal cords 21 and the non-metallic cords 22 in the bundle cord 23 is not particularly limited as long as the number is 3 or more, but preferably 3-15. The number is more preferably 3 to 10. In addition, all the bundle cords 23 in the treat member 20 may be the same or different in the number and arrangement position of the metal cords 21 and the non-metallic cords 22.

  Here, in the tire 10 of the present invention, the metal cord 21 may be formed by twisting a plurality of metal filaments (metal steel wires) or by using a single wire of metal filaments. Also good. There is no particular limitation on the structure of a cord (twisted cord) formed by twisting a plurality of metal filaments. For example, (N + M) such as (1 × N) structure such as (1 × 2) structure, (1 × 3) structure, (1 × 5) structure, (1 + 1) structure, (2 + 1) structure, (2 + 2) structure, etc. ) Structure can be suitably used. Among these twisted cords, a (1 × N) structure is preferable. In particular, a bundle of two cords having a (1 × 2) structure has a smaller diameter than other twisted cord structures, so that the treat member 20 can be made thin and excellent in terms of lightness. In addition, about conditions, such as a twist direction of a metal filament, and a twist pitch, it does not restrict | limit in particular, It can design suitably according to a conventional method.

As the metal filament used for the metal cord 21, for example, a filament formed of steel, brass, copper, alloy, or the like can be used. However, a steel filament is most commonly used. The steel filament is mainly composed of steel and can contain various trace contents such as carbon, manganese, silicon, phosphorus, sulfur, copper, and chromium. It is preferable to use a steel filament having a tensile strength of 2700 N / mm ² or more.

  In the tire 10 of the present invention, the metal filament constituting the metal cord 21 preferably has a plating layer formed on the surface thereof by a conventional method. Although it does not specifically limit as a plating layer, For example, a zinc plating layer, a copper plating layer, a brass (brass) plating layer etc. are mentioned, Among these, from a viewpoint of adhesiveness with rubber | gum, brass (brass) plating A layer is preferred.

  Further, in the tire 10 of the present invention, examples of the nonmetallic cord 22 include polyamides such as nylon and aramid, polyesters such as polyethylene naphthalate (PEN) and polyethylene terephthalate (PET), and organic materials such as rayon, polyketone and vinylon. A twisted cord made of fiber can be suitably used, but besides these, carbon fiber, glass fiber, basalt fiber, and the like can also be used.

  In the tire 10 of the present invention, the mass ratio of the metal cord 21 and the nonmetal cord 22 in the treat member 20 is preferably 5:95 to 95: 5. By setting it as this range, the balance of the rigidity level difference and weight in the treat member 20 can be kept favorable.

  In the tire 10 of the present invention, the diameter ratio of the metal cord 21 and the non-metallic cord 22 in the treat member 20 is preferably 20:80 to 95: 5, more preferably 30:70 to 90. : 10. Thereby, distortion of the rubber layer between the cords can be reduced. From the viewpoint of reducing the weight of the treat member 20 and securing rigidity, the diameter of the metal cord 21 is preferably 0.15 to 0.70 mm.

  Furthermore, in the tire 10 of the present invention, if the number of driving the bundle cords 23 into the treating member 20 is too small, it may not be possible to secure the rigidity of the treating member 20. On the other hand, if the driving number is too large, The distance between the cord bundles in the member 20 in the width direction becomes narrow, and the rubber peeling starting from the cord end at the end of the treat member 20 easily propagates between adjacent cord bundles, making it difficult to suppress separation. Since it may become, it is not preferable. Therefore, the number of cords 23 to be driven into the treating member 20 may be appropriately designed after taking into account the number of cords constituting the bundle of the bundle cords 23.

  Furthermore, in the tire 10 of the present invention, the thickness of the treat member 20 is preferably 0.71 to 1.50 mm from the viewpoint of weight reduction and durability improvement of the tire. If the thickness of the treat member 20 is less than 0.71 mm, sufficient durability may not be obtained. On the other hand, if the thickness of the treat member 20 exceeds 1.50 mm, a sufficient light weight effect may not be obtained.

  The tire 10 of the present invention is not particularly limited with respect to other specific tire structures and materials as long as the treat member 20 is used, and known structures and materials can be adopted. . For example, in the type of tire 10 shown in the figure, the treat member 20 may be used for the belt layers 5a and 5b, and a known structure may be employed for the carcass 4 and the belt reinforcing layer 6. In this case, the belt layers 5a and 5b can be disposed so that the bundle cord 23 is inclined at an angle of, for example, 15 to 40 ° with respect to the tire circumferential direction. Moreover, the organic fiber cord extended in the direction substantially orthogonal to a tire circumferential direction, for example, an angle of 70-90 degrees, can be used for the carcass 4. The belt reinforcing layer 6 (cap layer 6a, layer layer 6b) can be made of organic fiber cords arranged substantially parallel to the tire circumferential direction. As the organic fiber cord, a cord made of a highly elastic organic fiber is preferably used. For example, aromatic polyamide (aramid), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), rayon, Zylon (registered trademark) (polyparaphenylene benzobisoxazole (PBO) fiber), aliphatic polyamide (nylon), polyketone What consists of at least 1 type of organic fibers, such as, can be used.

  As shown in the figure, a bead core 7 is embedded in each of the pair of bead portions 3 of the tire 10 of the present invention, and the carcass 4 is folded around the bead core 7 from the inside of the tire to the outside and locked. Alternatively, it may be structured to be wound around the bead core 7 and locked (not shown), or may be sandwiched and locked by a bead wire from both sides (not shown), and any fixing method may be used. Good. Furthermore, in the tire 10 of the present invention, a tread pattern may be appropriately formed on the surface of the tread portion 1, and an inner liner (not shown) may be formed in the innermost layer. Furthermore, in the tire 10 of the present invention, as the gas filled in the tire, normal or air having a changed oxygen partial pressure, or an inert gas such as nitrogen can be used. The tire 10 of the present invention is suitable for a pneumatic tire for passenger cars.

Hereinafter, the tire of this invention is demonstrated in detail using an Example.
<Examples 1-5 and Comparative Examples 1-4>
A pneumatic tire having a tire size of 195 / 65R15 was manufactured under the following conditions. Carcass ply (rayon, 1840 dtex / 3, number of twists: 40 × 40/10 cm, number of shots: 80 pieces / 10 cm, angle with respect to tire circumferential direction: 90 °) is one sheet, the belt is a two-layer belt layer, tire It arrange | positioned so that the angle with respect to the circumferential direction might cross at +/- 35 degrees. In addition, one cap layer (number of drivings of 100/10 cm, angle with respect to the tire circumferential direction: 0 °) was disposed outside the belt in the tire radial direction. The constitution of the belt layer is as shown in Tables 1 and 2. In the table, SC means steel cord and TEX means organic fiber cord. Each of the obtained test tires was evaluated according to the following procedure.

<Tire weight>
The tire of Comparative Example 1 was designated as “Δ”, the tire that was lighter than 50 to 300 g lighter than this, and the tire that was lighter than 300 g was marked “◎”. The obtained results are also shown in Tables 1 and 2.

<Rolling resistance>
The internal pressure of each rim-assembled tire is set to 210 kPa, each tire is compliant with SAE J1269, the load mass is 450 kg, the tire is rolled at 80 km / h, and the drum has a steel plate surface with a diameter of 1.7 m. Using a test machine, the rolling resistance of the axle was measured and evaluated. The measured rolling resistance was indexed, with 100 (equivalent) being Δ, 97 to 99 being 〇, and 96 or less being ◎. The obtained results are also shown in Tables 1 and 2.

<Steering stability>
After mounting each test tire on a standard rim defined in the JTMA standard, the driving stability was evaluated by the driver's feeling running on a dry circuit. Equivalent to the tire of Comparative Example 1 was Δ, 場合 was very good, 〇 was excellent, × was inferior, × was inferior, and XX was greatly inferior. The obtained results are also shown in Tables 1 and 2.

<Durability>
The internal pressure of each rim-assembled tire is set to 180 kPa, and the test tire is placed on a steel drum tester having a diameter of 3 m, with a camber angle (CA) of 1 degree, a slip angle (SA) of 0 degree, and a load load of 8 kN. It was pressed and run continuously at 150 km / h for 100 hours. Thereafter, the tire was disassembled over the entire circumference of the tire, and the length of cracks in the crossing belt layer was measured. Of the measured cracks, the longest crack was used as an evaluation target. The evaluation criteria are the same as the tire of Comparative Example 1, Δ, the case of being excellent, and the case of being excellent. The obtained results are also shown in Tables 1 and 2.

※１：スチールコードと非金属コードの体積比
※２：スチールコードと非金属コードを束ねず均等に打ち込んだ構造
※３：１×２構造のスチールコード

* 1: Volume ratio of steel cord to non-metallic cord * 2: Structure in which steel cord and non-metallic cord are driven evenly without being bundled * 3: Steel cord with 1 × 2 structure

  From the above, it can be seen that the function of the tire of the present invention is improved.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass 5 Belt 6 Belt reinforcement layer 7 Bead core 10 Pneumatic tire (tire)
20 Treat member 21 Metal cord 22 Non-metal cord 23 Bundle cord 24 Coated rubber

Claims (4)

A tread portion, a sidewall portion, a bead portion, a carcass made of at least one carcass ply extending between the bead portions in a toroid shape, and at least 2 disposed on the outer side in the tire radial direction of the carcass In a pneumatic tire provided with a belt composed of a belt layer of layers,
A treating member in which a bundle cord formed by bundling a total of three or more metal cords and non-metal cords is coated with a coating rubber is used for the carcass and / or at least one belt layer,
At least one end of the bundle cord is a non-metallic cord, and
The pneumatic tire according to claim 1, wherein a volume ratio of the metal cord and the non-metal cord in the bundle cord is 5:95 to 95: 5.   The pneumatic tire according to claim 1, wherein a mass ratio of the metal cord to the non-metal cord in the treat member is 5:95 to 95: 5.   The pneumatic tire according to claim 1 or 2, wherein a diameter ratio of the metal cord to the non-metal cord in the treat member is 20:80 to 95: 5.   The pneumatic tire according to claim 1, wherein the treat member is at least one belt layer.

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