阅读说明：本技术 充气轮胎 (Pneumatic tire ) 是由 长谷川圭一 片山昌宏 于 2018-06-07 设计创作，主要内容包括：本发明的充气轮胎包括由被包覆树脂包覆的线材形成的树脂包覆带束层,在所述树脂包覆带束层的轮胎径向内侧设置有与所述树脂包覆带束层的轮胎宽度方向外侧端接触的底环,在所述底环的至少任一个面设有凹凸。(The pneumatic tire of the present invention includes a resin-coated belt layer formed of wire materials coated with a coating resin, a bottom ring that is provided on the inner side in the tire radial direction of the resin-coated belt layer and is in contact with the outer end of the resin-coated belt layer in the tire width direction, and irregularities provided on at least one surface of the bottom ring.)

1. A pneumatic tire comprising a resin-coated belt layer formed of a wire material coated with a coating resin, the pneumatic tire being characterized in that,

a bottom ring that is in contact with the outer end of the resin coated belt layer in the tire width direction is provided on the inner side of the resin coated belt layer in the tire radial direction,

at least one surface of the bottom ring is provided with a concave-convex.

2. The pneumatic tire of claim 1,

the irregularities are formed by grooves extending non-linearly in the tire circumferential direction.

3. The pneumatic tire of claim 2,

the groove width of the groove is more than 0.8mm and less than 2 mm.

4. The pneumatic tire according to any one of claims 1 to 3,

the projections and the depressions are formed on the tire width direction outer end surface of the bottom ring.

5. The pneumatic tire of claim 1,

the number of the projections and depressions is 4/mm, the maximum size of which is 0.1mm or more and 0.5mm or less²100 pieces/mm²Is formed on the face.

Technical Field

The present invention relates to a pneumatic tire.

Background

Conventionally, in a pneumatic tire, in order to exert a hoop effect of fastening a carcass and improve the rigidity of a tread, an operation of arranging a belt layer on the outer side of the carcass in the tire radial direction is generally performed (for example, patent document 1).

In recent years, in the course of increasing demands for weight reduction of tires, it has been proposed to use a structure in which a wire rod is coated with a coating resin as a belt layer. When such a resin is used to coat the belt layer, the resin has high rigidity compared to the weight, and therefore, the belt layer can function as the belt layer while achieving a reduction in weight.

Disclosure of Invention

Problems to be solved by the invention

However, in the case of using the resin-coated belt layer for the pneumatic tire, since the rigidity of the resin-coated belt layer is high, a rigidity step in which the rigidity in the tire circumferential direction changes sharply and largely in the tire width direction occurs with the tire width direction end portion of the resin-coated belt layer as a boundary. Therefore, the strain is likely to be large at the end of the resin-coated belt layer, and it is desirable to suppress the occurrence of failure at the end of the resin-coated belt layer due to the above situation to improve the durability of the tire. In contrast, it is also conceivable to reduce the stiffness difference by using a specific member, but in this case, it is also desired to suppress a failure due to the arrangement of the member and improve the durability of the tire.

Accordingly, an object of the present invention is to provide a pneumatic tire having improved durability.

Means for solving the problems

The main structure of the present invention is as follows.

The pneumatic tire of the present invention is characterized in that,

the pneumatic tire includes a resin-coated belt layer formed of a wire material coated with a coating resin,

a bottom ring that is in contact with the outer end of the resin coated belt layer in the tire width direction is provided on the inner side of the resin coated belt layer in the tire radial direction,

at least one surface of the bottom ring is provided with a concave-convex.

In the present specification, the "groove width" of the groove means the maximum width in the case where the groove width varies in the extending direction of the groove.

In the present specification, the "maximum dimension" means the maximum value of the distance between two points of the outer contour line in a plan view of the concave or convex portions of the irregularities when viewed from one irregularity, and when there are a plurality of irregularities, the "maximum dimension" means the dimension of the "maximum dimension" that is the largest among the plurality of irregularities.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a pneumatic tire having improved durability can be provided.

Drawings

Fig. 1 is a schematic partial cross-sectional view in the tire width direction showing a half portion in the tire width direction of a pneumatic tire according to an embodiment of the present invention.

Fig. 2A is a partial cross-sectional view showing a part of the resin-coated belt layer and the bottom ring of the pneumatic tire of fig. 1.

Fig. 2B is a partial sectional view showing another arrangement of the concavities and convexities.

Fig. 2C is a partial sectional view showing another arrangement of the concavities and convexities.

Fig. 2D is a partial sectional view showing another arrangement of the concavities and convexities.

Fig. 3A is a schematic view showing a bottom ring of the pneumatic tire of fig. 1, as viewed from a direction opposite to a surface provided with the concavities and convexities.

Fig. 3B is a schematic view showing an example in which the unevenness is a plurality of minute unevenness.

Fig. 4 is a schematic perspective view showing the resin-coated belt layer and the bottom ring.

FIG. 5 is a partial cross-sectional view showing another example of a resin-coated belt layer and a bottom ring.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail by way of examples with reference to the accompanying drawings.

Fig. 1 is a schematic partial cross-sectional view in the tire width direction showing a half portion in the tire width direction of a pneumatic tire according to an embodiment of the present invention. Fig. 1 shows only one half in the tire width direction with the tire equatorial plane CL as a boundary, and the other half is not shown, but the other half has the same structure. The pneumatic tire 1 of the present embodiment (hereinafter also simply referred to as a tire) includes a resin-coated belt layer 4 formed of a wire 4b coated with a coating resin 4a and a tread 5 in this order on the outer side in the tire radial direction of a crown portion of a carcass 3 which is embedded in a toroidal shape across bead cores 2a of a pair of bead portions 2.

In the present invention, the tire structure other than the belt structure and the structure of the after-mentioned bottom ring is not particularly limited, and can be constructed by using a usual rubber conventionally.

For example, although the present embodiment has the bead core 2a formed by binding steel wires, the material and shape of the bead core are not particularly limited, or a structure without the bead core 2a may be adopted. In the present embodiment, the carcass 3 is formed of a single carcass ply made of organic fibers, but the material and number of the carcass ply are not particularly limited.

In the present embodiment, the resin-coated belt layer 4 is a spiral belt layer in which a resin-coated wire material in which a coating resin 4a coats a wire material 4b is spirally wound around the tire axis. This enables the resin-coated belt layer 4 to be easily formed. In the present invention, the resin-coated belt layer 4 is preferably provided as one layer. This is because the resin in which the wire is wrapped has high rigidity, and therefore, the rigidity of the tread can be sufficiently increased by one layer, and this is preferable from the viewpoint of weight reduction. The width of the resin-coated belt layer 4 in the tire width direction can be set to, for example, 90% to 120% of the tire contact width.

The wires 4b can be made of any known material, and for example, steel cords can be used. The steel cord can be formed of, for example, steel monofilament or steel strand. In addition, organic fibers, carbon fibers, or the like can be used for the wires 4 b.

For example, a thermoplastic elastomer or a thermoplastic resin can be used as the coating resin 4a, and a resin that is crosslinked by heat or an electron beam or a resin that is cured by thermal rearrangement can be used. Examples of the thermoplastic elastomer include a polyolefin thermoplastic elastomer (TPO), a polystyrene thermoplastic elastomer (TPS), a polyamide thermoplastic elastomer (TPA), a polyurethane thermoplastic elastomer (TPU), a polyester thermoplastic elastomer (TPC), and a dynamically crosslinked thermoplastic elastomer (TPV). Examples of the thermoplastic resin include a polyurethane resin, a polyolefin resin, a vinyl chloride resin, and a polyamide resin. Further, as the thermoplastic resin, for example, a material having a deflection temperature under load (at a load of 0.45 MPa) of 78 ℃ or higher as specified in ISO 75-2 or ASTM D648, a tensile yield strength of 10MPa or higher as specified in JIS K7113, a tensile elongation at break (JIS K7113) of 50% or higher as specified in JIS K7113, and a Vicat softening temperature (method A) of 130 ℃ or higher as specified in JIS K7206 can be used. The tensile modulus of elasticity (defined in JIS K7113: 1995) of the coating resin 4a of the coated wire rod 4b is preferably 50MPa or more. The tensile modulus of elasticity of the coating resin 4a coating the wire rod 4b is preferably 1000MPa or less. The coating resin 4a described here does not contain rubber (an organic polymer substance exhibiting rubber elasticity at normal temperature).

The spiral belt layer can be formed, for example, by: the resin-coated wire rod is formed by coating the outer peripheral side of the wire rod 4b with the coating resin 4a in a molten state and solidifying the coating resin by cooling, and the resin-coated wire rod is joined together by melting the coating resin 4a by hot plate welding or the like and welding the resin-coated wire rods adjacent in the axial direction to each other in an annular body formed by winding the resin-coated wire rod. Alternatively, the spiral belt layer may be formed by bonding and joining together the resin-coated wires adjacent to each other in the axial direction in the formed annular body with an adhesive or the like.

As shown in fig. 1, in the tire 1 of the present embodiment, a bottom ring 6 (at least a part of which is located at the same position as the tire width direction outer end 4c of the resin coated belt layer 4 in the tire width direction) that is in contact with the tire width direction outer end 4c of the resin coated belt layer 4 is provided on the tire radial direction inner side of the resin coated belt layer 4. In this example, the bottom ring 6 is an annular member (in this example, continuously extending in the tire circumferential direction) formed of resin. The resin may be the same resin as the coating resin 4a of the resin-coated belt layer 4, or may be a resin different from the coating resin 4a of the resin-coated belt layer 4. Even when the resin of the bottom ring 6 is different from the coating resin 4a of the resin-coated belt layer 4, the thermoplastic elastomer or the thermoplastic resin exemplified above as the material of the coating resin 4a can be used.

As shown in fig. 1, the tire width direction inner end 6a of the bottom ring 6 is located inward in the tire width direction from the tire width direction outer end 4c of the resin coated belt layer 4, and the tire width direction outer end 6b of the bottom ring 6 is located outward in the tire width direction from the tire width direction outer end 4c of the resin coated belt layer 4. In the present invention, it is preferable that the width of the bottom ring 6 in the tire width direction is 7% or more of the width of the resin-coated belt layer 4 in the tire width direction. This is because the resin-coated belt layer 4 can be easily disposed at the time of production (particularly, when the spiral belt layer is wound) by setting the ratio to 7% or more. It is also preferable that the tire width direction center position of the bottom ring 6 is set to the tire width direction outer end 4c of the resin coated belt layer 4 and the tire width direction position in the vicinity thereof. This is because the resin-coated belt layer 4 can be easily disposed at the time of manufacture (particularly, when the spiral belt layer is wound), and the effect of relaxing the difference in rigidity between the resin-coated belt layer 4 and the rubber can be more reliably exhibited by the bottom ring 6, which will be described later. The thickness of the bottom ring 6 may be 0.5mm to 2mm, and the distances in the tire width direction from the tire width direction outer end 4c of the resin-coated belt layer 4 to the tire width direction inner end and outer end of the bottom ring 6 may be 0mm or more, respectively. The "width in the tire width direction" of the ground ring 6 and the resin-coated belt layer 4 and other dimensions in this specification are dimensions measured in a state where the tire is mounted on the application rim, the standard internal pressure is applied, and the tire is set in an unloaded state (here, the "tire ground contact width" is a distance in the tire width direction between the ground contact ends in a state where the tire is mounted on the application rim, the standard internal pressure is applied, the ground contact ends in a state where the maximum load is applied are set as the ground contact ends, and the tire is mounted on the application rim, the standard internal pressure is applied, and the ground contact ends in a state where the tire is set in an unloaded state). In The present specification, The "application Rim" refers to an industrial standard effective in a region where tires are produced and used, and refers to JATMA (japan automobile Tire Association) jatmayer BOOK in japan, STANDARDS MANUAL of ETRTO (The European type and Rim technical organization) in europe, and STANDARDS MANUAL of YEAR and Rim BOOK of TRA (The Tire and Rim Association, Inc.) in The united states, or a standard Rim in application sizes described in The future (measuringrim in STANDARDS MANUAL of ETRTO, and Design Rim in YEAR BOOK of TRA). (that is, the "rim" includes not only the current size but also the size that the industrial standard will include in the future. as an example of the "size described in the future", a size described as "FUTUREDEVELOPMENTS" in STANDARDS MANUAL 2013 edition of ETRTO can be cited), and in the case of a size that is not described in the industrial standard, the "rim" refers to a rim having a width corresponding to the bead width of the tire. The "standard internal pressure" refers to an air pressure (maximum air pressure) corresponding to the tire maximum load capacity of the JATMA standard or the like, for a tire of the applied size. In the case of a size not described in the above-mentioned industrial standards, "standard internal pressure" refers to an air pressure (maximum air pressure) corresponding to a maximum load capacity specified for each vehicle on which the tire is mounted. The "maximum load" means a tire maximum load capacity of a tire of an application size according to the JATMA standard or the like, or a load corresponding to a maximum load capacity specified for each vehicle on which the tire is mounted when the size is not described in the industry standard.

Fig. 2A is a partial cross-sectional view showing a part of the resin-coated belt layer and the bottom ring of the pneumatic tire of fig. 1. As shown in fig. 2A, in the present embodiment, the bottom ring 6 has a substantially rectangular (oblong) cross section.

As shown in fig. 2A, in the present embodiment, the bottom ring 6 has irregularities 6e on either surface thereof. In the example shown in fig. 2A, the irregularities 6e are provided on the surface of the bottom ring 6 that forms the tire width direction outer end 6 b.

Fig. 3A is a schematic view showing a bottom ring of the pneumatic tire of fig. 1. As shown in fig. 3A, in the present embodiment, the irregularities 6e are formed by grooves 6f extending in the tire circumferential direction.

The operation and effect of the present embodiment will be described below.

In the pneumatic tire according to the present embodiment, since the bottom ring 6 that is in contact with the tire width direction outer end 4c of the resin coated belt layer 4 is provided on the tire radial direction inner side of the resin coated belt layer 4, the rigidity step that is bounded by the tire width direction outer end 4c of the resin coated belt layer 4 can be relaxed, compared to a case where a sharp rigidity step occurs between the resin coated belt layer 4 and rubber in the tire width direction (a case where the bottom ring 6 is not provided).

In the present embodiment, since the unevenness 6e having a size in the above-described range is provided on the surface of the bottom ring 6 forming the tire width direction outer end 6b, the adhesion area between the surface and the rubber is increased, the adhesion between the bottom ring 6 and the rubber is improved, and the separation between the bottom ring 6 and the rubber is suppressed.

In addition, in the present embodiment, since the unevenness 6e is formed by the groove 6f extending non-linearly in the tire circumferential direction, it is assumed that the progress of the crack can be suppressed even when the crack is generated at the interface between the rubber and the surface of the bottom ring 6 forming the tire width direction outer end 6b, because the crack proceeds along a longer path than in the case where the groove is provided linearly.

As described above, according to the pneumatic tire of the present embodiment, the durability of the tire can be improved.

Fig. 2B to 2D are partial cross-sectional views showing other arrangements of the concavities and convexities 6 e. In the example shown in fig. 2B, the unevenness 6e is provided on the surface of the bottom ring 6 forming the outer end 6c in the tire radial direction. In the example shown in fig. 2C, the irregularities 6e are provided on the surface of the bottom ring 6 that forms the tire width direction inner end 6 a. In the example shown in fig. 2D, the unevenness 6e is provided on the surface of the bottom ring 6 forming the tire radial direction inner end 6D.

As described above, in the previous embodiment shown in fig. 2A, the irregularities 6e are provided on the surface forming the tire width direction outer end 6B, but in the present invention, for example, by providing the aforementioned irregularities 6e on at least one surface of the bottom ring 6 as shown in fig. 2B to 2D, the bonding area between the surface provided with the irregularities 6e and the rubber can be increased, and the same operational effects as described above can be obtained.

In the examples shown in fig. 2A to 2D, the irregularities 6e are provided only on one surface of the bottom ring 6, but in the present invention, from the viewpoint of increasing the bonding area between the bottom ring 6 and the rubber, the irregularities 6e are preferably provided on two or more surfaces of the bottom ring 6, and more preferably, the irregularities 6e are provided on all surfaces of the bottom ring 6.

The irregularities 6e may be provided on the entire surface of the bottom ring 6 or may be provided on a part of each surface.

As described above, in the present invention, it is preferable that the irregularities 6e be formed by the grooves 6f extending non-linearly in the tire circumferential direction. This is because it is assumed that the progress of cracks can be suppressed even when cracks are generated at the interface between the rubber and the (uneven) surface of the bottom ring 6, and the reason for this is that the crack progress path is longer than in the case where grooves are provided linearly.

In this case, the groove width of the groove 6f is preferably 0.8mm or more and 2mm or less. This is because the groove width can be reliably set to a value that can increase the contact area by 0.8mm or more, and on the other hand, the groove width can be set to a value that does not cause a large portion of the groove 6f that is not bonded to the rubber by 2mm or less, so that the contact area between the bottom ring 6 and the rubber is not reduced to the contrary.

In this case, the groove 6f is non-linear (for example, zigzag or curved), but the maximum amplitude in the tire width direction is preferably 3mm or less. By setting the thickness to 3mm or less, the groove 6f can be set to a level that does not largely generate a portion that is not bonded to the rubber, and the contact area between the bottom ring 6 and the rubber is not reduced.

In the present invention, it is particularly preferable that the irregularities 6e be formed on the surface of the base ring 6 that forms the tire width direction outer side end 6 b. This is because, since the crack is likely to occur at the interface between the bottom ring 6 and the rubber, if the crack is likely to occur at the interface between the rubber and the surface of the bottom ring 6 forming the tire width direction outer end 6b, the progress of the crack can be most effectively suppressed.

Here, fig. 3B is a schematic view showing an example in which the unevenness is a plurality of minute unevenness, and is viewed from a direction facing a surface on which the unevenness is provided. In the present invention, it is preferable that the number of the irregularities 6e having a maximum dimension of 0.1mm or more and 0.5mm or less is 4/mm²100 pieces/mm²Is formed on at least any one surface of the bottom ring 6. This is because the bonding area between the bottom ring 6 and the rubber can be increased more effectively.

In this case, as shown in fig. 2A to 2D, the concave-convex portion 6e may be formed on at least one surface of the bottom ring 6. On the other hand, in view of increasing the bonding area between the bottom ring 6 and the rubber, the irregularities 6e are preferably formed on two or more surfaces, and the irregularities 6e are more preferably formed on all the surfaces.

Further preferably, the maximum depth of the irregularities 6e is 0.03mm to 3.2mm (preferably 0.4mm to 3.2 mm).

Fig. 4 is a schematic perspective view showing the resin-coated belt 4 and the bottom ring 6. In this example, a groove 6f extending in a zigzag manner in the tire circumferential direction is formed in the tire width direction outer end surface 6b of the base ring 6. As described above, the groove width of the groove 6f is preferably 0.8mm or more and 2mm or less. In this case as well, similarly to the above-described embodiment, it is assumed that the progress of the crack can be suppressed even when the crack is generated at the interface between the rubber and the (uneven) surface of the bottom ring 6, because the crack has a longer path to progress than the case where the groove is provided linearly.

FIG. 5 is a partial cross-sectional view showing another example of a resin-coated belt layer and a bottom ring. In this example, the cross-sectional shape of the resin-coated wire is a parallelogram, and the cross-sectional shape of the resin-coated belt layer 4 is also a parallelogram.

The embodiments of the present invention have been described above, but the above embodiments do not limit the present invention at all. For example, in fig. 3A, two grooves 6f extending in a zigzag shape along the tire circumferential direction are formed, but the number of grooves is not particularly limited as long as there is one or more grooves, and the grooves may extend in a curved shape instead of in a zigzag shape. In addition, the joining strength between the bottom ring 6 and the resin-coated belt layer 4 can be improved by providing irregularities also on the surface of the bottom ring 6 which is the joining surface between the bottom ring 6 and the resin-coated belt layer 4. Further, the bottom ring 6 may have, for example, a wire material extending in the tire circumferential direction inside the bottom ring 6.

Description of the reference numerals

1. A pneumatic tire; 2. a bead portion; 2a, a bead core; 3. a carcass; 4. coating the belted layer with resin; 4a, coating resin; 4b, wire rods; 4c, coating the outer end of the belt layer in the tire width direction with resin; 5. a tread; 6. a bottom ring; 6a, the tire width direction inner end of the bottom ring; 6b, the tire width direction outer end of the bottom ring; 6c, the outer end of the bottom ring in the tire radial direction; 6d, the inner side end of the bottom ring in the tire radial direction; 6e, concave-convex; 6f, grooves (concave-convex); CL, tire equatorial plane.