JP7022649B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire (hereinafter, also simply referred to as a "tire"), and more particularly to a pneumatic tire provided with a treat member capable of improving the durability of the tire and the like.

In general, a belt that is a reinforcing member of a carcass that forms the skeleton of a pneumatic tire is mainly composed of a steel belt layer that is a rubberized layer of steel cords that are inclined and arranged with respect to the equatorial plane of the tire, and two steel belt layers are provided. As described above, the steel cords are arranged so as to intersect each other. However, since the belt layer made of steel cord works to increase the weight, there is a trade-off relationship with fuel efficiency performance. Under such circumstances, a technique of replacing the steel cord of the steel belt layer with an organic fiber cord has been proposed in order 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 the cords are coated with a rubber material. By using this corded rubber sheet as a constituent material such as a tire belt layer and a carcass ply, the running performance and the kinetic performance of the tire are improved, and fuel efficiency is realized by reducing the weight.

Japanese Unexamined Patent Publication No. 08-72160

However, in recent years, the performance required for tires has become more and more sophisticated, and even if the corded rubber sheet proposed in Patent Document 1 is applied to carcass pliers and belt layers, it may not always be satisfactory. At present, further improvement is desired.

Therefore, an object of the present invention is to provide a pneumatic tire provided with a treat member capable of improving the durability of the tire and the like.

As a result of diligent studies to solve the above problems, the present inventor covers a bundle of metal cords in which two or more metal cords are bundled and a bundle of non-metal cords in which two or more non-metal cords are bundled. We have found that the above problems can be solved by using a treat member coated with rubber as a reinforcing material for a tire, and have completed the present invention.

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 in a toroid shape straddling between the bead portions, and the carcass. In a pneumatic tire comprising a belt consisting of at least two layers of belts arranged on the outer side in the tire radial direction.
The carcass and the treat member, in which a bundle of metal cords in which only two or more metal cords are bundled and a bundle of non-metal cords in which only two or more non-metal cords are bundled, are covered with a coated rubber. / Or used for at least one belt layer,
The volume ratio of the metal cord to the non-metal cord in the treat member is 5:95 to 95: 5.
It is characterized in that the bundle of the metal cord and the bundle of the non-metal cord are arranged apart from each other.

In the tire of the present invention, the mass ratio of the metal cord to the non-metal cord in the treat member is preferably 5:95 to 95: 5. In particular, in the tire of the present invention, the treat member is suitable for at least one belt layer.

According to the present invention, it is possible to provide a pneumatic tire provided with a treat member that can improve the durability of the tire and the like. In particular, by using the treat member as a belt layer, the tire weight can be reduced, and rolling resistance, steering stability and durability can be improved.

It is the schematic sectional drawing in the tire width direction of the pneumatic tire which concerns on one preferred embodiment of this invention. It is a cross-sectional view in the width direction of the treat member used for the pneumatic tire which concerns on one preferred embodiment of this 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 of a pneumatic tire according to a preferred embodiment of the present invention in the tire width direction, and the illustrated tire 10 has a tread portion 1 forming a ground contact portion and a tread portion thereof. A pair of sidewall portions 2 continuously extending inward in the tire radial direction on both side portions of 1 and a bead portion 3 continuous on the inner peripheral side of each sidewall portion 2 are provided. In the illustrated tire 10, the tread portion 1, the sidewall portion 2 and the bead portion 3 are reinforced by a carcass 4 composed of a single carcass ply extending from one bead portion 3 to the other bead portion 3 in a toroid shape. 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, a belt 5 composed of at least two belt layers arranged on the outer side of the carcass 4 in the tire radial direction, and in the illustrated example, two layers of a first belt layer 5a and a second belt layer 5b. However, in the tire 10 of the present invention, the belt layer may be three or more layers. Further, in the illustrated tire 10, the belt reinforcing layer 6 is arranged on the outer side of the belt 5 in the tire radial direction. The belt reinforcing layer 6 may be one or both of the cap layer 6a arranged over the entire width of the belt 5 and the layer layers 6b arranged at both end regions of the belt 5.

FIG. 2 shows a cross-sectional view in the width direction of a treat member used for a pneumatic tire according to a preferred embodiment of the present invention. The tire 10 of the present invention has a bundle of metal cords having two or more metal cords 21 and four bundled in the illustrated example, and a non-metal bundle having two or more non-metal cords 22 and four bundled in the illustrated example. The treat member 20 formed by covering the bundle of cords with the coated rubber 23 is used, for example, as a carcass ply, belt layers 5a, 5b, etc., preferably belt layers 5a, 5b. Here, the metal cord 21 and the non-metal cord 22 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 in which the metal cord 21 and the non-metal cord 22 are used in combination, the weight can be reduced as compared with the case where the treat member composed of only the metal cord is used. can. Further, by bundling the metal cord 21 and the non-metal cord 22 respectively, the in-plane rigidity of the treat member 20 is increased. 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, since the treat member 20 uses a bundle of metal cords 21 and a bundle of non-metal cords 22 in combination, it is compared with the case where only the bundle of metal cords is used. Since the rigidity step between the coated rubber 23 and the bundle of non-metal cords is small, the durability of the treat member 20 is improved, and 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 the rubber starting from the cord end at the end in the belt width direction propagates between the adjacent cords is suppressed. When used for a carcass ply, the ply end separation starting from the end of the carcass ply can be suppressed.

In the tire 10 of the present invention, the volume ratio of the metal cord 21 and the non-metal cord 22 in the treat member 20 is 5:95 to 95: 5. Within such a range, the effect of the present invention can be satisfactorily obtained. If the bundle of metal cords and the bundle of non-metal cords are used in combination, there is no particular limitation on the arrangement form of the bundle of metal cords 21 and the bundle of non-metal cords 22 in the treat member 20, for example. The bundles of the metal cords 21 and the bundles of the non-metal cords 22 may be arranged alternately, and in the treat member 20, a part where the bundles of the metal cords 21 are continuous or a bundle of the non-metal cords 22 may be arranged. There may be continuous points. In the tire 10 of the present invention, the number of bundles of the metal cord 21 and the bundle of the non-metal cord 22 is not particularly limited as long as it is two or more, but it is preferable. It is 2 to 15, more preferably 2 to 10. Further, the number of cords of the bundle of metal cords 21 and the bundle of non-metal cords 22 may be the same or different.

Here, in the tire 10 of the present invention, as the metal cord 21, a tire made by twisting a plurality of metal filaments (metal steel wires) may be used, or a tire made of a single wire of metal filaments may be used. May be good. There is no particular limitation on the structure of the cord (twisted cord) formed by twisting a plurality of metal filaments. For example, (1 × 2) structure, (1 × 3) structure, (1 × 5) structure and other (1 × N) structures, (1 + 1) structure, (2 + 1) structure, (2 + 2) structure and other (N + M) structures. ) The structure can be preferably used. Among these twisted cords, a (1 × N) structure is preferable. In particular, since the bundle of two cords having a (1 × 2) structure has a smaller diameter than the structure of other twisted cords, the treat member 20 can be made thinner, which is excellent in terms of lightness. The conditions such as the twisting direction and the twisting pitch of the metal filament are not particularly limited, and can be appropriately designed according to a conventional method.

As the metal filament used for the metal cord 21, for example, a filament formed of steel, brass, copper, an alloy or the like can be used, but it is most common to use a steel filament. The steel filament contains steel as a main component and can contain various trace substances such as carbon, manganese, silicon, phosphorus, sulfur, copper and chromium. As the steel filament, 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, it is preferable that the metal filament constituting the metal cord 21 has a plating layer formed on the surface thereof by a conventional method. The plating layer is not particularly limited, and examples thereof include a zinc plating layer, a copper plating layer, a brass (brass) plating layer, and the like. Among these, brass plating is performed from the viewpoint of adhesion to rubber. Layers are preferred.

Further, in the tire 10 of the present invention, the non-metal cord 22 includes, for example, polyamide such as nylon and aramid, polyester such as polyethylene naphthalate (PEN) and polyethylene terephthalate (PET), and organic such as rayon, polyketone and vinylon. A twisted cord made of fibers can be preferably used, but in addition to these, carbon fibers, glass fibers, basalt fibers and the like can also be used.

In the tire 10 of the present invention, the mass ratio of the metal cord 21 to the non-metal cord 22 in the treat member 20 is preferably 5:95 to 95: 5. Within such a range, the balance between the rigidity step and the weight of the treat member 20 can be well maintained.

Further, in the tire 10 of the present invention, the diameter ratio of the metal cord 21 and the non-metal cord 22 in the treat member 20 is preferably 20:80 to 95: 5, more preferably 30:70 to 90. : 10. This makes it possible to reduce the distortion of the rubber layer between the cords. From the viewpoint of reducing the weight and ensuring the rigidity of the treat member 20, the diameter of the metal cord 21 is preferably 0.15 to 0.70 mm.

Further, in the tire 10 of the present invention, if the number of the bundles of the metal cords 21 and the bundles of the non-metal cords 22 driven into the treat member 20 is too small, the rigidity of the treat member 20 may not be ensured, which is not preferable. If the number of driving is too large, the distance between the bundles of cords in the treat 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 can easily be performed between the bundles of adjacent cords. It is not preferable because it may be difficult to suppress the separation that propagates to the tire. Therefore, the number of bundled cords driven into the treat member 20 may be appropriately designed in consideration of the number of cords constituting the bundle of metal cords 21 and the bundle of non-metal cords 22.

Furthermore, in the tire 10 of the present invention, the thickness of the treat member 20 is preferably 0.71 mm to 1.50 mm from the viewpoint of reducing the weight of the tire and improving the durability. 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, it may not be possible to obtain a sufficient lightweight effect.

As long as the tire 10 of the present invention uses the treat member 20, other specific tire structures and materials are not particularly limited, and known structures and materials can be adopted. .. For example, in the illustrated type of tire 10, the treat member 20 may be used for the belt layers 5a and 5b, and a known structure may be adopted for the carcass 4 and the belt reinforcing layer 6. In this case, the belt layers 5a and 5b can be arranged so that the bundle of the metal cord 21 and the bundle of the non-metal cord 22 are inclined at an angle of, for example, 15 to 40 ° with respect to the tire circumferential direction. Further, for the carcass 4, an organic fiber cord extending in a direction substantially orthogonal to the tire circumferential direction, for example, at an angle of 70 to 90 ° can be used. Further, for the belt reinforcing layer 6 (cap layer 6a, layer layer 6b), organic fiber cords arranged substantially parallel to the tire circumferential direction can be used. As the organic fiber cord, it is preferable to use a cord made of highly elastic organic fiber. For example, aromatic polyamide (aramid), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), rayon, Zylon (registered trademark) (polyparaphenylene benzobisoxazole (PBO) fiber), aliphatic polyamide (nylon), polyketone. Etc., which are composed of at least one kind of organic fiber, can be used.

Further, as shown in the figure, a bead core 7 is embedded in each pair of bead portions 3 of the tire 10 of the present invention, and the carcass 4 is locked around the bead core 7 by folding back from the inside to the outside of the tire. The structure may be wound around the bead core 7 and locked (not shown), or may be sandwiched between bead wires from both sides and locked (not shown), and either fixing method may be used. good. Further, 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 on the innermost layer. Furthermore, in the tire 10 of the present invention, as the gas to be filled in the tire, normal or an inert gas such as nitrogen or an air having a different oxygen partial pressure can be used. The tire 10 of the present invention is suitable for a pneumatic tire for a passenger car.

Hereinafter, the tire of the present invention will be described in more detail with reference to examples.
<Comparative Examples 1 to 4 and Examples 1 to 6>
Tire size: 195 / 65R15 pneumatic tires were manufactured under the following conditions. One carcasply (rayon, 1840 dtex / 3, number of twists: 40 x 40/10 cm, number of drives: 80 lines / 10 cm, angle with respect to tire circumferential direction: 90 °), the belt is a two-layer belt layer, and the tire The tires were arranged so that the angles with respect to the circumferential direction intersected at ± 35 °. Further, one cap layer (number of hits: 100/10 cm, angle with respect to the tire circumferential direction: 0 °) was arranged on the outer side of the belt in the tire radial direction. The structure of the belt layer is as shown in Tables 1 and 2. In the table, SC means a steel cord and TEX means an organic fiber cord. Each of the obtained test tires was evaluated according to the following procedure.

<Tire weight>
The tires of Comparative Example 1 were designated as Δ, those that were 50 to less than 300 g lighter than this were designated as ◯, and those that were 300 g or more lighter were designated as ⊚. The obtained results are also shown in Tables 1 and 2.

<Rolling resistance>
The internal pressure of each tire assembled on the rim 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 an iron plate surface with a diameter of 1.7 m. The rolling resistance of the axle was measured and evaluated using a testing machine. The measured rolling resistance was indexed, and 100 (equivalent) was set to Δ, 99 to 97 was set to 〇, and 96 or less was set to ⊚. The obtained results are also shown in Tables 1 and 2.

<Maneuvering stability>
After mounting each test tire on the standard rim specified in the JATTA standard, the steering stability was evaluated by the driver's feeling running on the dry circuit. Equivalent to the tire of Comparative Example 1 is △, very excellent is ◎, excellent is 〇, inferior is ×, significantly inferior is XX, and significantly inferior is XX. It was marked as x. The obtained results are also shown in Tables 1 and 2.

<Durability>
The internal pressure of each tire assembled on the rim is set to 180 kPa, and the test tire is mounted on a steel drum tester with a diameter of 3 m with a camber angle (CA) -1 degree, slip angle (SA) 0 degree, and load load 8 kN. It was pressed and ran continuously for 100 hours at 150 km / h. After that, it was disassembled over the entire circumference of the tire, and the length of cracks in the crossed belt layer was measured. Among the measured cracks, the longest crack was evaluated. As the evaluation criteria, the same as the tire of Comparative Example 1 was evaluated as Δ, and the excellent case was evaluated as 〇. 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 and non-metal cord * 2: Structure in which steel cord and non-metal cord are evenly driven without bundling * 3: Steel cord with 1 x 2 structure

※４：炭素繊維

* 4: Carbon fiber

From the above, it can be seen that the tire of the present invention has various functions improved.

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 Covered rubber

Claims (3)

A tread portion, a sidewall portion, a bead portion, a carcass composed of at least one carcass ply extending in a toroid shape straddling the bead portions, and at least 2 arranged outside the tire radial direction of the carcass. In a pneumatic tire equipped with a belt consisting of layers of belt layers,
The carcass and the treat member, in which a bundle of metal cords in which only two or more metal cords are bundled and a bundle of non-metal cords in which only two or more non-metal cords are bundled, are covered with a coated rubber. / Or used for at least one belt layer,
The volume ratio of the metal cord to the non-metal cord in the treat member is 5:95 to 95: 5.
A pneumatic tire characterized in that the bundle of metal cords and the bundle of non-metal cords are arranged apart from each other . The pneumatic tire according to claim 1, wherein the 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 the treat member is at least one belt layer.

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