TIRES

Abstract

A tire is provided comprising a belt layer and a sponge element on an inner surface of a tread section in a tire radial direction, wherein the belt layer comprises a steel cord consisting of one to four filaments and a cover rubber covering the steel cord, wherein the cover rubber is composed of a rubber composition comprising a rubber component, wherein a density D of the sponge element is less than 20 kg / m3, and wherein M is greater than 2.5 and D / M is less than 7.0, where M=R / WL×104, where R represents a cord diameter in mm of the steel cord and WL represents a maximum load capacity in kg of the tire.

Description

TECHNICAL AREA The present invention relates to a tire. STATE OF THE ART To improve a tire's fuel efficiency, weight reduction of tire components is desirable. JP 2007-302203 A describes a tire manufactured to achieve both durability and weight reduction at a high level by embedding steel cords with a filament diameter of 0.15 to 0.26 mm and a filament count of 5 to 7 in a belt layer. On the other hand, to improve the noise reduction performance of a tire, a noise-reducing element, such as a sponge or similar material, can be attached to the tire. However, it is essential that such a noise-reducing element has the ability to deform flexibly as it follows the deformation of the tire to prevent damage to the element itself. SUMMARY OF THE INVENTION One object of the present invention is to provide a tire that can improve overall performance in terms of fuel efficiency and durability. The present invention relates to: a tire comprising a belt layer and a sponge element on an inner surface of a tread section in a tire radial direction, wherein the belt layer comprises: a steel cord consisting of one to four filaments, and a cover rubber covering the steel cord, wherein the cover rubber is composed of a rubber composition comprising a rubber component, wherein the density D of the sponge element is less than 20 kg / m³, and wherein M is greater than 2.5 and D / M is less than 7.0, where M is defined as follows: M = R / WL × 10⁴, where R represents a cord diameter in mm of the steel cord and WL represents a maximum load capacity in kg of the tire. According to the present invention, a tire is provided which can improve overall performance in terms of fuel efficiency and durability. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a tire according to an embodiment of the present invention. Fig. 2 is a view schematically showing a belt layer according to the present embodiment. Fig. 3 is a view schematically showing the belt layer in the vicinity of a tire center section. Fig. 4 is a perspective view of an example of a configuration of a simply twisted steel cord. EXECUTIONAL FORM FOR IMPLEMENTING THE INVENTION A tire that is an embodiment of the present invention is a tire comprising a belt layer and a sponge element on an inner surface of a tread section in a tire radial direction, wherein the belt layer comprises a steel cord consisting of one to four filaments and a cover rubber covering the steel cord, wherein the cover rubber is composed of a rubber composition comprising a rubber component, wherein a density D of the sponge element is less than 20 kg / m3, and wherein M is greater than 2.5 and D / M is less than 7.0, where M is defined as follows: M = R / WL× 104, where R represents a cord diameter in mm of the steel cord and WL represents a maximum load capacity in kg of the tire. Although it is not intended to be bound to any theory, the following may be considered as a reason why the durability of the tire of the present invention is improved. (1) If the number of filaments of the steel cord comprising the belt layer is four or fewer, the weight of the tire can be reduced. However, there are concerns regarding a reduction in durability. If a value of M, calculated as a ratio of the cord diameter R of the steel cord to the maximum load capacity WL of the tire, is within the predetermined range described above, such a configuration is considered to contribute to the suppression of a reduction in durability. (2) On the other hand, if the number of filaments of the steel cord is small, the movement of the steel cord becomes large, which in turn causes the movement of the sponge element to also become large as it follows the movement of the steel cord. Therefore, there are concerns regarding the deterioration of the durability of the sponge element. Accordingly, if the density D of the sponge element and a value of D / M are within the predetermined ranges described above, such a configuration is assumed to help suppress the deterioration of the durability of the sponge element. By combining the above described (1) and (2), it is assumed that in a tire with a sponge element, a remarkable effect of improving fuel efficiency by reducing the weight of the tire, while maintaining the durability of the sponge element, will be achieved. The steel cord preferably has a 1 × 1 structure or a 1 × 4 structure. Since such an aspect allows for a small amount of cover rubber while maintaining tire durability, it is assumed that fuel efficiency will be further improved by reducing the tire's weight. If E represents the number of steel cords arranged per 50 mm in a tire width direction, D / E is preferably less than 0.17. If the number E of arranged steel cords is small, the movement of the steel cord becomes large, thus improving tire durability. However, the movement of the sponge element also becomes large, as it follows the movement of the steel cord, and therefore there are concerns about a deterioration in the durability of the sponge element. If D / E is within the range described above, it is assumed that a deterioration in the durability of the sponge element can be suppressed. If Fr represents the bending stiffness in g • cm of the steel cord, D / Fr is preferably less than 1.7. If the bending stiffness Fr of the steel cord is low, the movement of the steel cord becomes large, thus improving tire durability. However, the movement of the sponge element also becomes large as it follows the movement of the steel cord, and therefore there are concerns about a deterioration in the durability of the sponge element. If D / Fr is within the range described above, it is assumed that a deterioration in the durability of the sponge element can be suppressed. From the point of view of suppressing deterioration of durability, the content of a cobalt element based on 100 parts by mass of the rubber component in the rubber composition is preferably 2.85 × 10-3 parts by mass or less. The rubber composition preferably includes silicon dioxide. When silicon dioxide is incorporated into the tread rubber, stiffness can be reduced in a tiny deformation zone of the tread rubber. This improves the adhesion between the steel cord and the tread rubber, and is believed to further enhance tire durability. The steel cord preferably comprises a ternary plating layer composed of copper, zinc and cobalt. When a ternary plating is used, it is assumed that cobalt, which has a stronger ionization tendency than copper, is preferentially eluted, so that enlargement of the adhesive layer due to elution of copper after hygrothermal aging is suppressed and adhesive strength can be kept high. It is preferred that the belt layer comprises a first belt layer and a second belt layer laminated to the outside of the first belt layer in a tire radial direction, and that b / a is 1.5 or more, where "a" represents the shortest distance between a steel cord of the second belt layer in the tire's central section and the steel cords of the first belt layer, and "b" represents the shortest distance between a steel cord located at the outermost end of the second belt layer and the cords of the first belt layer. If b / a is within the range described above, such a configuration is considered to contribute to improved durability at a belt end. The distance between both the upper and lower surfaces of the first belt ply in the tire's center section and a cord, as well as the distance between both the upper and lower surfaces of the second belt ply in the tire's center section and a cord, is preferably 0.14 mm or less. It is assumed that using such a configuration contributes to improved fuel efficiency. The tire according to the present embodiment preferably includes an electronic component. The tire according to the present embodiment can be used as a tire for an electric car, a tire for a hybrid car or a tire for a plug-in hybrid car. In the present description, respective numerical values ​​accompanied by "or more (higher)", "greater (higher) than", "or less (lower)" or "less (lower) than" with respect to the boundary of a range of numbers can form ranges of numbers by any combination thereof, as long as such ranges of numbers are not inconsistent with the spirit of the present invention. Furthermore, for these respective numerical values, ranges of numbers can also be formed by combining numerical values ​​in examples as their upper or lower bound.In a case where a number range formed in such a manner is shown to be a number range containing its limit, such a numerical value can be interpreted as simultaneously showing a number range that does not contain its limit, in any arbitrarily selectable manner, as long as such a number range is not inconsistent with the spirit of the present invention. Therefore, for example, a number range shown to be a number range containing both limits at its two ends can be interpreted as showing not only such a number range, but also a number range that either does not contain one of its limits or a number range that does not contain either of the limits, as long as such number ranges are not inconsistent with the spirit of the present invention.Furthermore, a range of numbers shown to contain only one of its limits and not the other of the limits can be interpreted as showing not only such a range of numbers, but also a range that does not contain either of its limits, as long as such a range of numbers is not inconsistent with the spirit of the present invention. <definitionen> A "tread section" is a section that forms a ground contact area of ​​a tire and is an element that, in relation to elements forming a tire skeleton with steel or textile material, such as a belt layer, a belt reinforcement layer, a carcass layer and the like, is located in a cross-section in the tire radial direction on an outside in a tire radial direction when the tire includes these elements. A "belt layer" is one of the reinforcing layers and consists of at least one belt ply. Several belt cords that make up a belt layer are arranged substantially parallel to each other, and one direction of extension of a belt cord is inclined at 10° or greater relative to a tire circumference. The belt includes a connecting section on the circumference of the tire. Here, the phrase "substantially parallel" means that the angular difference of one direction of extension of each belt cord with respect to the tire circumference is within a range of ±3°. A "band" is one of the reinforcing layers and consists of at least one band ply. A band cord forming a band ply is arranged in a state where the band cord is wound spirally in one direction around the tire, and the angle at which the band cord's extension is inclined relative to the tire's circumference remains within 5°. The band does not include any connecting part on the tire's circumference. A "standardized condition" is a state in which the tire is mounted on a standardized rim, inflated to a standardized internal pressure, and under no load. Unless otherwise noted, a tire is used in a standardized condition. Unless otherwise specified, a “dimension of each part of a tire” is a value specified in a standardized condition for one appearing on the outer surface of the tire, while for one present inside the tire, or for one on a tire cut surface, it is a value specified in a condition in which, for example, the tire is cut on a plane containing a tire axis of rotation and the cut piece of tire is held to a rim width of a standardized rim. A "standardized rim" is a rim within a standard system that includes a standard on which the tire is based, and which is defined by the standard for each tire. For example, "standardized rim" refers to a standard rim of an applicable size described in the "JATMA YEAR BOOK" by JATMA (The Japan Automobile Tire Manufacturers Association, Inc.), a "Measuring Rim" described in the "STANDARDS MANUAL" by ETRTO (The European Tyre and Rim Technical Organisation), or a "Design Rim" described in the "YEAR BOOK" by TRA (The Tire and Rim Association, Inc.), referenced in that order, and if an applicable size exists at the time of reference, the rim conforms to its standard.Furthermore, in the case of a tire that is not defined by the standard, the "standardized rim" shall refer to a rim with the narrowest rim width among rims that can be mounted on the tire, that can maintain internal pressure (i.e., cause no air leakage between the rim and the tire), and that have the smallest rim diameter. A “standardized internal pressure” is an air pressure in a standard system containing a standard on which the tire is based, defined by the standard for each tire, and, for example, refers to a “MAXIMUM AIR PRESSURE” at JATMA, “INFLATION PRESSURE” at ETRTO, or to a maximum value described in the table “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” at TRA, referenced in that order, as in the case of the standardized rim, and if there is an applicable size at the time of reference, the standardized internal pressure conforms to its standard.Furthermore, in the case of tires not defined by the standard, the standardized internal pressure shall refer to a standardized internal pressure (250 kPa or more) of another tire size (specified in the standard) for which the standardized rim is described as a standard rim, and if several standardized internal pressures of 250 kPa or more are described, it shall refer to the minimum value below that. A "standardized load" is a load in kg within a standard system that includes a standard on which the tire is based. This load is defined by the standard for each tire, for example, a "MAXIMUM LOAD CAPACITY" for JATMA, a "LOAD CAPACITY" for ETRTO, or a maximum value described in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" table for TRA. Reference is made to these values ​​in that order, as in cases of a standardized rim and standardized inflation pressure. If an applicable size exists at the time of reference, the load conforms to its standard. Then, in the case of tires not defined by the standard, a maximum load capacity (WL) obtained through calculation is defined as a standardized load. A "maximum load capacity WL" in kg is calculated using the following equation. "V" represents a virtual volume in mm³ of a tire, "Dt" represents a tire's outer diameter in mm in a standardized state, "Ht" represents a cross-sectional height in mm of the tire in a radial direction in a cross-section of the tire along a plane containing a tire axis of rotation, and "Wt" represents a cross-sectional width in mm of the tire in the standardized state. If R represents a rim diameter of the tire, Ht can be calculated using the following equation: (Dt - R) / 2. Wt is a value obtained by excluding any patterns, letters, or the like on the tire's sidewall. Furthermore, the maximum load capacity has the same meaning as a standardized load as described above. A “tire center section” shall refer to a section that is located within a distance from a tire equator plane in a tire width direction, where the distance is equal to one quarter of a tire ground contact width. A "filament" is a strand that forms a steel cord. A “rubber component of a rubber composition” refers to a component that contributes to crosslinking in the rubber composition and is generally a component with a weight mean molecular weight (Mw) of 10,000 or more. A "plasticizer" is a material that imparts plasticity to a rubber component and is a component extracted from a rubber compound using acetone. Examples of plasticizers include one that is liquid at 25°C and one that is solid at 25°C. However, the plasticizer should not contain wax or stearic acid, which are commonly used in the tire industry. A “plasticizer content” also includes an amount of a plasticizer contained in a stretched rubber component that has previously been stretched with the plasticizer, such as an oil, resin component, liquid rubber component, and the like. Furthermore, the same applies to an oil content, a resin component content, and a liquid rubber content; for example, in a case where the stretching component is oil, the stretching oil is included in the oil content. <messverfahren> The “density D of a sponge element” refers to an “apparent density” measured according to JIS K 7222:2005. Its unit is kg / m³. A "cord diameter R of a steel cord" refers to the diameter of a filament in a case where the steel cord is a single monofilament cord, or is calculated as the diameter of a circumscribed circle of an aggregate of filaments in a case where the steel cord is configured as a twisted wire obtained by twisting several filaments together. Its unit is mm. The bending stiffness Fr of a steel cord is calculated using a stiffness tester (for example, model 150-D, manufactured by Taber Industries) by averaging the bending moment at +15 degrees and the bending moment at -15 degrees when both ends of a 145 mm long steel cord are clamped and the cord is bent at either a +15-degree or a -15-degree angle. The unit is g • cm. The “average thickness of a plating layer” is measured according to JIS H 8501:1999. A “specific nitrogen adsorption surface (N2SA) of soot” is measured according to JIS K 6217-2:2017. A “specific nitrogen adsorption surface (N2SA) of silicon dioxide” is measured by a BET method according to ASTM D3037-93. An "average primary particle size" is a value calculated by arithmetic meaning the particle sizes of 400 particles photographed with a transmission or scanning electron microscope. In cases where the particle is spherical, the diameter of the sphere is defined as the particle size; for shapes other than spherical, an equivalent circular diameter (positive square root of "4 × (area of ​​particle) / π") calculated from a microscope image is defined as the particle size. The average primary particle size is applied to silicon dioxide, carbon black, and similar materials. A process for producing a tire, which is an embodiment of the present invention, is described in detail below. However, the following descriptions are for illustrative purposes only and are not intended to limit the technical scope of the present invention to this description. <reifen> The tire according to the present embodiment comprises a belt layer and a sponge element on the inside of a tread section in a tire radial direction. Furthermore, the belt layer comprises a steel cord consisting of one to four filaments and a cover rubber that covers the steel cord. Although the tire of an embodiment of the present invention is described below with reference to the drawings, the drawings are for illustrative purposes only. Moreover, the embodiment described below is merely an example. Fig. 1 shows a cross-sectional view of a tire 11 according to the present embodiment on a plane passing through a tire axis of rotation. Although only parts on the right side of CL (tire centerline) are shown in Fig. 1, the tire also has a similar continuous structure on the left side of CL when CL is used as an axis of symmetry. As shown in Fig. 1, the tire 11 comprises a tread section 1, a sidewall 32, a bead section 33, a carcass 34, a belt layer 7, a band 36 and a sponge element 39. The bead section 33 comprises a bead core 31. The belt layer 7 comprises a first belt layer 5 and a second belt layer 6, which is laminated to the outside of the first belt layer 5 in the tire radial direction. The number of layers is not particularly limited and can be selected arbitrarily. The belt 36 is composed of an edge belt 61, which covers only an edge portion of the belt 35, and a full belt 62, which covers the entire area of ​​the belt 5, although the present invention is not limited to such an aspect. The tread section 1 can be a tread section consisting of a single rubber layer, or a tread section comprising a rubber top layer forming a tread surface and one or more rubber layers present between the rubber top layer and the band 36. The tire 11 preferably comprises an electronic component (not shown in the drawings). Examples of the electronic component include, for example, a sensor for detecting an internal condition of the tire, such as air pressure in the tire, and the like, and a wireless tag equipped, for example, with a recording element that records unique identification information of the tire, and the like. (Sponge element) The tire according to the present embodiment comprises a sponge element. Although the position of the sponge element within the tire is not restricted as long as it is located on the inside of the tread section 1 in the tire's radial direction, it is preferably fixed to an inner cavity surface 15 along a tire's circumferential direction. The sponge element 39 is preferably shaped like a long strip with a base surface that is fixed to the inner cavity surface 15. At this point, the outer end portions of the sponge element can be brought into contact with each other in the circumferential direction to form the sponge element into a substantially ring-shaped form, or they can also be separated from each other in the circumferential direction. The sponge element 39 has essentially the same cross-sectional shape at every position in the circumferential direction except for the outer end portions. A horizontally long, flat shape with a height less than the width in a tire axial direction is preferred for this cross-sectional shape to prevent camber or deformation during driving. The sponge element 39 preferably includes a recessed groove 37 located on the inner surface side in the tire radial direction and extending continuously in the circumferential direction. The presence of the recessed groove 37 is assumed to increase the surface area of ​​the sponge element 39, thereby enabling greater absorption of resonance energy and improving heat dissipation, thus simplifying the suppression of temperature rise in the sponge element. The electronic component and the like described above can be firmly fixed to the recessed groove 37. The sponge element according to the present embodiment is a porous structure, and its cells (pores) can be communication pores or closed cells and are preferably communication pores. A suitable porous structure is a foamed body made of synthetic resin or synthetic rubber. Alternatively, the porous structure can be a net-like structure obtained by interlacing animal fibers, plant fibers, synthetic fibers, or the like to integrally couple these fibers together. Examples of materials for the foamed body (foam) include, but are not limited to, for example, synthetic resins such as polyurethane, polystyrene, polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), and the like; and synthetic rubbers such as ethylene-propylene-diene rubber (EPDM), silicone rubber, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butyl rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber (ECO), and the like. Among these, polyurethane is preferred for its noise-reducing performance, lightness, foam conformability, durability, and similar properties. For example, in a case where polyurethane foam is used as a sponge element, the polyurethane foam can be produced by a known process using raw materials for polyurethane, such as polyol, polyisocyanate, a catalyst, a foam stabilizer, a foaming agent and the like. In a case where the sponge element is a foamed body, its density can be suitably adjusted by the types or amounts of a catalyst, a foam stabilizer, a foaming agent and the like combined in a raw material. For the purposes of the effects described in the present invention, the density D of the sponge element is less than 20 kg / m³, preferably 17 kg / m³ or less, more preferably 15 kg / m³ or less, even more preferably 13 kg / m³ or less, and particularly preferably 10 kg / m³ or less. On the other hand, for the purpose of reducing running noise, a lower limit for the density D of the sponge element is preferably 8.0 kg / m³ or more, more preferably 8.5 kg / m³ or more, and even more preferably 9.0 kg / m³ or more, but is not specifically limited to these values. From the perspective of sufficient conversion of vibrational energy from air, the volume of the sponge element is preferably 0.4% or more, preferably 1% or more, and even more preferably 2% or more of the total volume of a tire's inner cavity. Furthermore, the volume of the sponge element is preferably 30% or less, preferably 20% or less, and even more preferably 10% or less of the total volume of the tire's inner cavity. Here, the volume of the sponge element signifies an apparent total volume of the sponge element, where the apparent total volume is determined from a contour containing internal air bubbles. In the present description, the total volume Vi of the tire's internal cavity in a standardized state, in which a tire is rim-mounted on a standardized rim, filled with air at a standardized internal pressure, and no load is applied, is to be approximately calculated by the following equation (1).Furthermore, “A” below refers to an area surrounded by a tire cavity surface and a line segment connecting endpoints on the inside of a pair of bead sections in the tire radial direction, where “A” denotes a lateral cross-sectional area in mm of a tire cavity obtained by performing a CT scan on the tire-rim assembly in the standardized state, “Di” denotes a maximum outside diameter in mm of the tire cavity surface in the standardized state, and “Dr” denotes a rim diameter in mm. (belt layer and steel cord) Fig. 2 is a schematic cross-sectional view of the belt layer 7. As shown in the drawing, the first belt layer 5 and the second belt layer 6 comprise several steel cords (5A, 6A) and cover rubbers (5B, 6B). The multiple steel cords are arranged parallel in a line. Furthermore, the cover rubbers cover the steel cords, and the entire circumference of individual steel cords is accordingly covered by the cover rubbers. If “a” represents the shortest distance between a steel cord 6A of the second belt layer 6 in the tire's central section and the steel cords 5A of the first belt layer 5, and “b” represents the shortest distance between a steel cord 6A located at the outermost end of the second belt layer 6 and the steel cords 5A of the first belt layer 5, then b / a is preferably 1.5 or more, more preferably 1.7 or more, and even more preferably 1.9 or more. If b / a is within the ranges described above, such a configuration is considered to contribute to improved durability at belt end sections. Furthermore, from a fuel efficiency perspective, b / a is preferably 4.5 or less, more preferably 4.0 or less, even more preferably 3.5 or less, and particularly preferably 3.0 or less.Furthermore, “b” is intended to represent essentially a shortest distance between a steel cord located at the outermost end of the second belt layer and a curved line formed by an edge, at the outermost end in the tire radial direction, of several steel cords that are parallel to each other in the first belt layer (a dashed line L in Fig. 2). Fig. 3 is a schematic cross-sectional view of the central section of the belt layer 7, which is a section enclosed by a dashed line in Fig. 2. Both distances from the interfaces of the first belt layer 5 to the steel cords 5A in the tire central section (i.e., a distance c1 from the upper surface to the cords 5A and a distance c2 from the lower surface to the cords 5A) are preferably 0.18 mm or less, more preferably 0.15 mm or less, still more preferably 0.14 mm or less, and particularly preferably 0.12 mm or less. It is assumed that the use of such a configuration contributes to an improvement in fuel efficiency. Furthermore, lower limits for the distances from the interfaces of the first belt layer 5 to the steel cords 5A in the tire central section are preferably 0.03 mm or more and more preferably 0.05 mm or more, but are not specifically restricted thereto. For the same reason, both distances from the upper and lower surfaces of the second belt layer 6 to the cords 6A in the tire's central section (i.e., a distance c3 from the upper surface to the cords 6A and a distance c4 from the lower surface to the cords 6A) are preferably 0.18 mm or less, more preferably 0.15 mm or less, even more preferably 0.14 mm or less, and particularly preferably 0.12 mm or less. Furthermore, lower limits for the distances from the upper and lower surfaces of the second belt layer 6 to the cords 6A in the tire's central section are preferably 0.03 mm or more and more preferably 0.05 mm or more, but are not specifically restricted to these values. The steel cords are inclined relative to the tire's circumference. The angle of inclination of the steel cords relative to the tire's circumference is not particularly limited, but is typically set to a range of 0° to 60°. The steel cords according to the present embodiment comprise one to four steel strands, which are also referred to as filaments. That is, each of the steel cords can be a single monofilament cord (i.e., a cord with a 1 × 1 structure and consisting of one filament) or can comprise two to four filaments. In a case where a steel cord has two to four filaments, the steel cord preferably has a twisted structure in which these filaments are twisted together along their longitudinal direction. The twisted structure is not particularly restricted and can, for example, be a simply twisted steel cord with a 1 × N structure or a layer-twisted steel cord with an M + N structure. The simply twisted structure can, for example, be expressed as a 1 × N structure. The 1 × N structure means a structure in which N filaments are twisted to form a single layer. The single layer means a structure in which filaments are arranged on a cross-sectional plane perpendicular to the longitudinal direction of a steel cord such that the filaments form a single layer along a circumferential direction of a circle. Examples of the simply twisted structure in the present embodiment include a 1 × 2 structure, a 1 × 3 structure, and a 1 × 4 structure. Fig. 4 is a perspective view of a steel cord with a 1 × 2 structure. In a steel cord 50 shown in Fig. 4, two filaments 51 are spirally twisted along the longitudinal direction to form a single layer. The layer-twisted structure is a structure in which multiple filaments are wound sequentially in layers from a central section on the cross-sectional plane perpendicular to the longitudinal direction of a steel cord to form multiple layers. The layer-twisted structure can, for example, be expressed as an N+M structure. The N+M structure signifies a structure comprising a core in which N filaments are twisted to become helical along its longitudinal direction, and an outer sheath in which M filaments are helically twisted along the longitudinal direction of the core to cover its circumference. Examples of the layer-twisted structure in the present embodiment include a 2+2 structure. Each of the steel cords preferably has a 1 × 1 or a 1 × 4 structure. This design allows for a reduction in the amount of cover rubber required while maintaining tire durability, thus further improving fuel efficiency through weight reduction. Materials for steel filament are not particularly restricted, and HT (High Tensile), SHT (Super High Tensile), UHT (Ultra High Tensile), and similar materials can be used. Furthermore, recycled iron obtained by melting down scrap iron products can be used. Additionally, in cases where a steel cord is used, obtained by twisting together several steel filaments, pre-formed steel filaments in a longitudinal direction can be used to improve durability by facilitating penetration of the top layer of rubber into the steel cord. A plating layer can be applied to a steel cord according to the present embodiment. Since a steel cord with a plating layer exhibits high adhesion to humidity and heat even under difficult conditions of high temperature and high humidity, detachment of the outer rubber from the steel cord can be prevented, and the durability of the tire under hygrothermal conditions can be improved. Furthermore, in a case where a steel cord comprises multiple filaments, a plating layer can be applied to the surface of each filament. Although the configuration of a plating layer is not particularly restricted, a plating layer comprising a copper layer and a zinc layer is preferred, and a plating layer comprising a copper layer, a zinc layer, and a cobalt layer is further preferred. In particular, since a steel cord comprising a ternary plating layer composed of copper (Cu), zinc (Zn), and cobalt (Co) exhibits high adhesion performance against humidity and heat even under harsh conditions of high temperature and humidity, separation of the outer rubber from the steel cord can be prevented, and the durability of the tire under hygrothermal conditions can be improved. From the perspective of suppressing overreaction of copper, the zinc content in a plating layer is preferably 15 wt% or more, more preferably 20 wt% or more, and even more preferably 25 wt% or more. Furthermore, from the perspective of suppressing deterioration of adhesion due to excessive zinc oxide formation, it is preferably 44 wt% or less, more preferably 40 wt% or less, even more preferably 36 wt% or less, and particularly preferably 32 wt% or less. For the purpose of adhesion, the copper content in a plating layer is preferably 55 wt% or more, more preferably 58 wt% or more, and even more preferably 61 wt% or more. Furthermore, for the purpose of preventing rubber deterioration due to copper elution under hygrothermal conditions, the copper content is preferably 78 wt% or less, more preferably 75 wt% or less, and even more preferably 72 wt% or less. From the perspective of moist-warm adhesion, the cobalt content in a plating layer is preferably 1.0 wt% or more, more preferably 2.0 wt% or more, and even more preferably 3.0 wt% or more. Furthermore, from the perspective of preventing cracking during wire drawing, it is preferably 8.0 wt% or less, more preferably 7.0 wt% or less, and even more preferably 6.0 wt% or less. The plating layer can be formed by creating a copper layer, a zinc layer, a cobalt layer, and the like on each filament by plating prior to wire drawing, followed by heat treatment to diffuse the metal of each layer formed on the filament's surface. Furthermore, the stacking sequence of the layers formed on the filament to create the plating layer is not particularly restricted. Next, wire drawing is performed on a heat-treated material to create a filament with a desired diameter, thus forming a filament with a plating layer. If a steel cord is built from a single filament, the wire-drawn steel cord can be used as is. Alternatively, if a steel cord consists of multiple filaments, the wire-drawn steel cord can be configured to have a plating layer by twisting the resulting filaments to create, for example, a desired twisted structure. From the perspective of initial adhesion, the average thickness of the plating layer is preferably 0.10 µm or more, more preferably 0.13 µm or more, and even more preferably 0.16 µm or more. Furthermore, from the perspective of suppressing excessive adhesion, it is preferably 0.40 µm or less, more preferably 0.35 µm or less, and even more preferably 0.30 µm or less. From the perspective of the effects of the present invention, the cord diameter R of a steel cord is preferably 0.15 mm or more, more preferably 0.20 mm or more, even more preferably 0.25 mm or more, even more preferably 0.30 mm or more, even more preferably 0.35 mm or more, and particularly preferably 0.40 mm or more. On the other hand, from the perspective of reducing the tire's weight, the cord diameter R of the steel cord is preferably 0.75 mm or less, more preferably 0.65 mm or less, even more preferably 0.55 mm or less, and particularly preferably 0.45 mm or less. The number E of steel cords arranged per 50 mm in a tire width direction (also referred to as ends) is preferably 40 or more, more preferably 45 or more, still more preferably 50 or more, still more preferably 55 or more, and particularly preferably 60 or more, but is not particularly limited thereto. Furthermore, E is preferably 100 or less, more preferably 95 or less, and still more preferably 90 or less. The bending stiffness Fr of a steel cord, from the perspective of the effects of the present invention, is preferably 5.0 g / cm or more, more preferably 10 g / cm or more, even more preferably 20 g / cm or more, even more preferably 30 g / cm or more, even more preferably 40 g / cm or more, and particularly preferably 50 g / cm or more. On the other hand, an upper limit for Fr is preferably 80 g / cm or less, more preferably 70 g / cm or less, and even more preferably 60 g / cm or less, but is not specifically limited to these values. Furthermore, the bending stiffness Fr of the steel cord can be suitably adjusted by changing the configuration of the steel cord or the cord diameter D. For the sake of better realizing the effects of the present invention, the maximum load capacity WLin kg of the tire is preferably 400 or more, more preferably 450 or more, and even more preferably 500 or more. Furthermore, WLin kg is preferably 1300 or less, more preferably 1200 or less, and even more preferably 1100 or less. Additionally, WLin kg can be increased by increasing a virtual volume V of the space occupied by the tire and can also be decreased conversely. Since M is defined as follows: M = R / WL× 104, from the perspective of durability, M is greater than 2.5, preferably greater than 3.0, more preferably greater than 3.5, even more preferably greater than 4.0, and most preferably greater than 4.5. On the other hand, an upper limit of M is preferably less than 20 and more preferably less than 15, but is not particularly restricted thereto. From the perspective of the present invention, D / M is less than 7.0, preferably less than 6.0, more preferably less than 5.0, even more preferably less than 4.0, even more preferably less than 3.5, and particularly preferably less than 3.0. On the other hand, a lower limit of D / M is preferably more than 0.3 and more preferably more than 0.5, but is not specifically limited thereto. From the perspective of sponge durability, the D / E ratio is preferably less than 0.26, more preferably less than 0.23, even more preferably less than 0.20, and most preferably less than 0.17. On the other hand, a lower limit for D / E is preferably more than 0.08 and more preferably more than 0.10, but is not particularly restricted thereto. From the perspective of sponge durability, the D / Fr ratio is preferably less than 3.0, more preferably less than 2.5, even more preferably less than 2.0, even more preferably less than 1.7, even more preferably less than 1.4, and most preferably less than 1.0. On the other hand, a lower limit for D / Fr is preferably more than 0.10 and more preferably more than 0.15, but is not specifically restricted to these values. [Rubber composition] A rubber composition according to the present embodiment, which forms the cover rubber that covers the steel cord of the belt layer 7 (and which is referred to below as a rubber composition according to the present embodiment), is one that comprises a rubber component, and each rubber composition according to the present embodiment can be produced using raw materials described below. The rubber composition according to the present embodiment is described below. <kautschukkomponente> For the rubber composition according to the present embodiment, a diene-based rubber is suitably used as a rubber component. Examples of diene-based rubbers include, for example, isoprene-based rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and the like.These diene-based rubbers can be modified rubbers, each treated with a modified group that can interact with a filler such as carbon black, silicon dioxide, and the like, or they can be hydrogenated rubbers in which hydrogenation treatment has been performed on part of an unsaturated bond. The diene-based rubber can be used alone, or two or more can be used in combination. Furthermore, a stretched rubber, previously stretched with a softening agent described below, can also be used as a diene-based rubber. The content of a diene-based rubber in the rubber component is preferably 70 wt% or more, more preferably 80 wt% or more, even more preferably 90 wt% or more, and particularly preferably 95 wt% or more. Furthermore, the rubber component can consist of a diene-based rubber. At least one rubber component selected from the group consisting of an isoprene-based rubber, an SBR, and a BR is suitablely used. The rubber component preferably comprises an isoprene-based rubber or may be a rubber component consisting of an isoprene-based rubber. (Isoprene-based rubber) Isoprene-based rubbers commonly used in the tire industry, such as isoprene rubber (IR), natural rubber, and similar types, can be used. Examples of natural rubber include not only unmodified natural rubber (NR) but also modified natural rubbers, such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), ultrapure natural rubber, grafted natural rubber, and the like. These isoprene-based rubbers can be used individually, or two or more can be used in combination. The NR is not particularly restricted, and those commonly used in the tire industry can be used; examples include SIR20, RSS#3, TSR20, and the like. For the purposes of the present invention, the content of an isoprene-based rubber in the rubber component is preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, and particularly preferably 90% by weight or more. On the other hand, the upper limit of the content is not particularly restricted and can be 100% by weight. (SBR) An SBR is not particularly restricted; examples include an unmodified solution-polymerized SBR (S-SBR), an unmodified emulsion-polymerized SBR (E-SBR), modified SBRs thereof (a modified S-SBR, a modified E-SBR), and the like. Examples of modified SBRs include an SBR modified at its end and / or main chain, a modified SBR coupled with tin, a silicon compound, etc. (a modified SBR of condensate or with a branched structure, etc.), and the like. Among these, an S-SBR and a modified SBR are preferred. Furthermore, hydrogenated versions of these SBRs (hydrogenated SBRs) and the like may also be used. These SBRs may be used individually, or two or more of them may be used in combination. The content of an SBR in the rubber component is preferably less than 40 wt%, more preferably less than 20 wt%, even more preferably less than 10 wt% and particularly preferably less than 5 wt%, but is not particularly restricted thereto. (BR) A rubber (BR) is not particularly restricted, and those commonly used in the tire industry can be employed, such as a BR with a cis content of less than 50 mol% (a cis-poor BR), a BR with a cis content of 90 mol% or more (a cis-rich BR), a rare-earth-based butadiene rubber synthesized using a rare-earth-based catalyst (a rare-earth-based BR), a BR containing a syndiotactic polybutadiene crystal (an SPB-containing BR), a modified BR (a cis-rich modified BR, a cis-poor modified BR), and the like. These BRs can be used individually, or two or more of them can be used in combination. The content of BR in the rubber component is preferably less than 40 wt%, more preferably less than 20 wt%, even more preferably less than 10 wt% and particularly preferably less than 5 wt%, but is not particularly restricted thereto. (Other rubber components) The rubber component may comprise a rubber component other than diene-based rubbers (non-diene-based rubber), as long as it does not affect the effects of the present invention. A non-diene-based rubber may be a rubber component commonly used in the tire industry; examples include, for instance, butyl-based rubber, ethylene propylene rubber, polynorbornene rubber, silicone rubber, polyethylene chloride rubber, fluororubber (FKM), acrylic rubber (ACM), hydrin rubber, and the like. The other rubber components may be used alone, or two or more may be used in combination. Furthermore, in addition to the rubber components described above, it may or may not include a known thermoplastic elastomer. (Rubber component synthesized from recycled / biomass-derived raw material) A monomer that is a structural unit of a synthetic rubber, such as IR, SBR, BR, and the like, can be one derived from earth resources, such as petroleum, natural gas, and the like, or one recycled from a rubber product, such as a tire, and the like, or from a non-rubber product, such as polystyrene, and the like. Examples of monomers obtained through recycling (recycled monomers) include, but are not limited to, recycled polyisoprene, recycled butadiene, recycled aromatic vinyl compounds, and the like. Examples of butadiene, as described above, include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene and the like.These include recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene), preferably used as raw materials. A process for producing a recycled monomer is not particularly restricted; examples include, for instance, the synthesis of a recycled monomer from recycled naphtha obtained by decomposing a rubber product, such as a tire. Furthermore, a process for producing recycled naphtha is not particularly restricted, and recycled naphtha can be obtained, for example, by decomposing a rubber product, such as a tire, under high temperature and high pressure, by decomposing it using microwaves, or by mechanical pulverization followed by extraction. Furthermore, a monomer that is a structural unit of a polymer, such as an IR, an SBR, a BR, and the like, can be one derived from biomass. In this description, "biomass" refers to a material derived from natural resources, such as plants and the like. Examples of biomass include, but are not limited to, agricultural, forestry, and fishery products, sugar, wood waste, plant residues after the capture of a useful component, plant-derived ethanol, biomass naphtha, and the like. Examples of biomass-derived monomers (biomass monomers) include, but are not specifically limited to, biomass-derived butadiene, biomass-derived aromatic vinyl compounds, and the like. Examples of butadiene, as described above, include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds, as described above, include, but are not specifically limited to, styrene and the like. Furthermore, a process for producing a biomass monomer is not specifically limited; examples include, for instance, a process by biological and / or chemical and / or physical conversion of an animal or plant, and the like.Microbial fermentation is representative of biological conversion, and examples of chemical and / or physical conversion include a process that uses a catalyst, a process that uses high heat, a process that uses high pressure, a process that uses an electromagnetic wave, a process that uses a critical fluid, and combinations thereof. Examples of a polymer synthesized from a biomass monomer component (biomass polymer) include, but are not specifically limited to, a polybutadiene rubber synthesized from biomass-derived butadiene, an aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or a biomass-derived aromatic vinyl compound, and the like. Examples of aromatic vinyl / butadiene copolymers include, for example, a styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene, and the like. Whether a polymer raw material is derived from biomass or not can be determined by pMC (percent modern carbon), measured according to ASTM D6866-10. Here, "pMC" represents the ratio of the 14C concentration of a sample to the 14C concentration of a modern standard carbon (modern standard reference) and is a value used as an index indicating the biomass ratio of a compound. The significance of this value is discussed below. In one mole of carbon atoms (6.02 × 10²³), there are approximately 6.02 × 10¹¹ carbon atoms (¹⁴C), which is about one trillionth the number of normal carbon atoms. The half-life of ¹⁴C is 5730 years, and its amount is steadily decreasing. Therefore, in fossil fuels such as coal, oil, natural gas, and the like, where it is assumed that 226,000 years or more have passed since carbon dioxide was absorbed from the atmosphere and fixed by plants and the like, all the ¹⁴C elements that were present at the beginning of the fixation process have decayed. Therefore, fossil fuels such as coal, oil, natural gas, and the like do not contain ¹⁴C in the current 21st century. Accordingly, chemical substances produced using these fossil fuels as raw materials also do not contain ¹⁴C. On the other hand, carbon-14 (¹⁴C) is constantly produced by cosmic rays, which cause nuclear reactions in the atmosphere. Therefore, decreases in ¹⁴C due to radioactive decay and production of ¹⁴C due to nuclear reactions are balanced, and the amount of ¹⁴C in Earth's atmospheric environment has remained constant. Consequently, the ¹⁴C concentration of substances derived from biomass resources that have circulated in the current environment is approximately 1 × 10⁻¹² mol% based on the total carbon atoms, as described above. Accordingly, by using the difference between these values, a biomass ratio in a given compound can be calculated. This 14C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, a 13C concentration (13C / 12C) and a 14C concentration (14C / 12C) are measured. For these measurements, a 14C concentration in circulating carbon in nature from 1950 onwards is used as the modern standard reference, which then becomes the reference for the 14C concentration. An oxalic acid standard provided by the National Institute of Standards and Technology (NIST) is used as a specific reference material. A specific radioactivity of carbon in this oxalic acid (radioactivity intensity of 14C per gram of carbon) is determined for each carbon isotope. 13C is corrected to a constant value, and a value corrected for attenuation from 1950 to the measurement date is used as a standard 14C concentration value (100%).A ratio of this value to an actual measured value for a sample is called a pMC value. Thus, when rubber is produced from a material derived from 100% biomass, the 14C concentration shows a value of approximately 110 pMC, since under normal conditions it is often not exactly 100, although there are regional variations and the like. On the other hand, when this 14C concentration is measured for a chemical substance derived from a fossil fuel, such as petroleum, it shows a value of approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0%, as mentioned above. Based on the above, it is suitable in terms of environmental protection to use a material such as a rubber with a high pMC value, and the like, that is, a material such as a rubber with a high biomass ratio, and the like, for a rubber composition. <Füllstoff> The rubber composition according to the present embodiment preferably comprises carbon black as a filler or may further comprise another filler, such as silicon dioxide or the like. In addition, the filler may be a filler consisting of carbon black and silicon dioxide. Examples of carbon black include, but are not limited to, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, and the like. A raw material for carbon black can be a biomass material, such as lignin, vegetable oil, and the like, or it can be pyrolysis oil obtained by pyrolyzing a used tire. Furthermore, a process for producing carbon black can be a combustion process, such as a furnace process, a hydrothermal carbonization (HTC) process, or a thermal carbon black process using methane pyrolysis, and the like. Products from ASAHI CARBON CO., LTD., Cabot Japan KK, TOKAI CARBON CO., LTD., Mitsubishi Chemical Corporation, Lion Corporation, NIPPON STEEL Chemical & Material Co., Ltd., Columbia Carbon Corporation, etc., can be used as commercially available products.The soot can be used alone, or two or more of them can be used in combination. Furthermore, as a carbon black other than the carbon black described above, carbon black from a biomass material, such as lignin and the like, or recovered carbon black obtained by pyrolysis of a carbon black-containing product, such as a tire and the like, and subsequently refined, can be used from the perspective of an environmental impact assessment, etc. In this description, the term "recovered carbon black" refers to carbon black obtained by pulverizing a product such as a used tire containing carbon black and the like, and burning the pulverized product. After the product has undergone oxidative combustion by heating in air, the ratio of mass to ash (ash content), which is a non-combustible component, is 13% by mass or more according to a thermal weight measurement method of JIS K 6226-2:2003. That is, the ratio of mass (amount of carbon) to weight loss due to the oxidative combustion of the recovered carbon black is 87% by mass or less. The recovered carbon black can be expressed as rCB. Recovered carbon black can be obtained from a pyrolysis process of a used pneumatic tire. EP 3427975 A, for example, describes, with reference to "Rubber Chemistry and Technology", Vol. 85, No. 3, pages 408 to 449 (2012), in particular pages 438, 440 and 442, that the recovered carbon black can be obtained by pyrolysis at 550 to 800 °C in the absence of oxygen or by vacuum pyrolysis at a relatively low temperature of an organic material (

[0027] ). As described in

[0004] of JP 6856781 B, such carbon black obtained by the pyrolysis process typically lacks a functional group on its surface (A Comparison of Surface Morphology and Chemistry of Pyrolytic Carbon Blacks with Commercial Carbon Blacks, Powder Technology 160 (2005) 190-193). The recovered carbon black can be one lacking a functional group on its surface, or it can be one treated to contain a functional group on its surface. Treating the recovered carbon black to contain a functional group on its surface can be carried out by a conventional method. For example, in EP 3173251 A, carbon black obtained from a pyrolysis process is treated with potassium permanganate under acidic conditions, yielding carbon black containing a hydroxyl group and / or a carboxyl group on its surface. Furthermore, in JP 6856781 B, carbon black obtained from a pyrolysis process is treated with an amino acid compound containing at least one thiol group or disulfide group, yielding carbon black with an activated surface.Examples of recovered carbon black according to the present embodiment also include carbon black that is treated to contain a functional group on its surface. The recovered carbon black can be that which is commercially available from Strebl Green Carbon Pte Ltd., LD Carbon, etc. From the perspective of its amplifying properties, the specific nitrogen adsorption surface area (N₂SA) of carbon black is preferably greater than 80 m² / g, more preferably greater than 90 m² / g, even more preferably greater than 100 m² / g, and particularly preferably greater than 110 m² / g. Furthermore, from the perspective of heat generation and processability, it is preferably less than 250 m² / g, more preferably less than 220 m² / g, and even more preferably less than 190 m² / g. The N₂SA of carbon black is also measured using the measurement method described above. From the perspective of reinforcement, the carbon black content based on 100 parts by mass of the rubber component is preferably 20 parts by mass or more, further preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more. Furthermore, from the perspective of heat suppression, it is preferably 100 parts by mass or less, further preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, and particularly preferably 70 parts by mass or less. (Silicon dioxide) Silicon dioxide is not particularly restricted, and those commonly used in the tire industry can be employed, such as silicon dioxide produced by a dry process (anhydrous silicon dioxide), silicon dioxide produced by a wet process (hydrous silicon dioxide), and the like. The source of silicon dioxide is also not particularly restricted and can be, for example, a raw material derived from a mineral, such as quartz, or a raw material derived from a biological substance, such as rice husks (for example, silicon dioxide from a biomass material, such as rice husks, and the like), or silicon dioxide recycled from a silicon dioxide-containing product. Among these, hydrous silicon dioxide produced by a wet process is preferred because it contains many silanol groups.Silicon dioxide can be used alone, or two or more of them can be used in combination. Silicon dioxide from a biomass material can be obtained, for example, by burning rice husks to obtain rice husk ash, extracting silicate from the rice husk ash using a sodium hydroxide solution, producing silicon dioxide by reacting the silicate with sulfuric acid in the same way as for conventional wet silicon dioxide, and filtering, washing with water, drying, and pulverizing the silicon dioxide precipitates. Silicon dioxide recycled from a product containing silicon dioxide can be silicon dioxide recovered from such a product as an electronic component, such as a semiconductor, a tire, a desiccant, a filter material like diatomaceous earth, or the like. Furthermore, the recovery method is not particularly restricted; examples include pyrolysis, decomposition by electromagnetic waves, and the like. Silicon dioxide recovered from an electronic component, such as a semiconductor or the like, or from a tire, is preferred. When silicon dioxide crystallizes, it is insoluble in water, and silicic acid, a component of it, cannot be used. Crystallization of silicon dioxide in rice hull ash can be suppressed by controlling the firing temperature and duration (see JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, Vol. 6, pp. 216-222, etc.). Amorphous silicon dioxide extracted from rice husks can be used, including those commercially available from Wilmar, etc. The specific nitrogen adsorption surface area (N₂SA) of silicon dioxide is preferably 110 m² / g or more, more preferably 130 m² / g or more, more preferably 150 m² / g or more, and particularly preferably 170 m² / g or more, considering fuel efficiency and abrasion resistance. Furthermore, it is preferably 350 m² / g or less, more preferably 300 m² / g or less, and more preferably 250 m² / g or less, considering fuel efficiency and processability. The N₂SA of silicon dioxide is also measured using the measurement method described above. An average primary particle size of silicon dioxide is preferably 24 nm or less, more preferably 22 nm or less, even more preferably 20 nm or less, and particularly preferably 18 nm or less. A lower limit for the average primary particle size, considering the dispersibility of silicon dioxide, is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 5 nm or more, but is not specifically restricted to these values. Furthermore, the average primary particle size of silicon dioxide is measured using the measurement method described above. The silicon dioxide content, when compounded, based on 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, but is not specifically limited thereto. Furthermore, the content is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. From the perspective of the effects of the present invention, the total filler content based on 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more. Furthermore, from the perspective of fuel efficiency and elongation at break, it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, and particularly preferably 70 parts by mass or less. (Other fillers) Fillers other than silicon dioxide and carbon black are not particularly restricted, and those commonly used in the tire industry, such as aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, magnesium sulfate, talc, clay, and the like, can be combined. These other fillers can be used alone, or two or more of them can be used in combination. (Silane coupling agent) Silicon dioxide is preferably used in combination with a silane coupling agent. The silane coupling agent is not particularly restricted, and any silane coupling agent conventionally used in the tire industry in combination with silicon dioxide may be used. Examples include mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like; sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl)disulfide, bis(3-triethoxysilylpropyl)tetrasulfide, and the like; and thioester-based silane coupling agents such as 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, 3-octanoylthio-1-propyltrimethoxysilane, and the like. Vinyl-based silane coupling agents, such as vinyltriethoxysilane, vinyltrimethoxysilane and the like;Amino-based silane coupling agents, such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and the like; glycydoxy-based silane coupling agents, such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and the like; nitro-based silane coupling agents, such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, and the like; chlorine-based silane coupling agents, such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, and the like;and the like. The rubber composition preferably combines a sulfide-based silane coupling agent and / or a mercapto-based silane coupling agent. For example, the silane coupling agents used can be those commercially available from Evonik Industries AG, Momentive Performance Materials, etc. These silane coupling agents can be used alone, or two or more can be used in combination. From the perspective of enhancing the dispersibility of silicon dioxide, the content of a silane coupling agent based on 100 parts by mass of silicon dioxide is preferably 1.0 parts by mass or more, further preferably 3.0 parts by mass or more, and even more preferably 5.0 parts by mass or more. Furthermore, from the perspectives of cost and processability, it is preferably 20 parts by mass or less, further preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less. <Wärmehärtbares Harz> It is preferred that the rubber composition according to the present embodiment comprises a thermosetting resin. Here, the thermosetting resin means a resin in which polymerization is carried out by heating to cause the polymers to form a network structure, so that the resin hardens and does not return to its original state. The thermosetting resin is not particularly restricted; examples include, for instance, a resorcinol resin, a modified resorcinol resin, a cresol resin, a modified cresol resin, a phenolic resin, a modified phenolic resin, and the like. These thermosetting resins can be used individually, or two or more of them can be used in combination. When these thermosetting resins are combined, adhesion to the cord, elongation at break, and a complex modulus of elasticity can be improved. Among these, the resorcinol resin, the modified resorcinol resin, and the modified cresol resin are preferred, with the modified resorcinol resin being further preferred. Examples of resorcinol resin include, for example, a resorcinol-formaldehyde condensate. Examples of modified resorcinol resin include, for example, those in which part of a repeating unit of a resorcinol resin is alkylated. Examples of cresol resin include, for instance, a cresol-formaldehyde condensate. Examples of modified cresol resin include, for instance, those in which a methyl group at the end of the cresol resin is modified to a hydroxyl group, and those in which part of a repeating unit of the cresol resin is alkylated. Examples of phenolic resins include those obtained by reacting phenol with aldehydes, such as formaldehyde, acetaldehyde, and furfural, using an acid or alkali catalyst. Those obtained by reaction using an acid catalyst (a novolac-type phenolic resin, etc.) are preferred. Furthermore, examples of modified phenolic resins include a resin obtained by modifying a phenolic resin using cashew nut oil, tall oil, linseed oil, animal and vegetable oils, unsaturated fatty acids, rosin, alkylbenzene resin, aniline, melamine, etc. The content of a thermosetting resin, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the perspectives of adhesion and durability. Furthermore, from the perspectives of suppressing adhesion reactions during vulcanization and preventing deterioration of durability after hygrothermal aging, it is preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, even more preferably 4.5 parts by mass or less, and particularly preferably 4.0 parts by mass or less. <Härtungsmittel> It is preferred that the rubber composition according to the present embodiment comprises a curing agent for curing the thermosetting resin described above. The curing agent is not particularly restricted; examples include hexamethoxymethylmelamine (HMMM), a modified etherified methylolmelamine resin, hexamethylenetetramine (HMT), pentakis(methoxymethyl)methylolmelamine, tetrakis(methoxymethyl)dimethylolmelamine, and the like. The modified etherified methylolmelamine resin is preferred. These curing agents can be used individually, or two or more of them can be used in combination. The content of a hardening agent, when combined, based on 100 parts by mass of the rubber component, is, from the perspective of the effects of the present invention, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 0.7 parts by mass or more. Furthermore, the content is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, and even more preferably 2.0 parts by mass or less. <kobaltverbindung> It is preferred that the rubber composition forming a cover rubber includes a cobalt compound. When the rubber composition includes the cobalt compound, the adhesive strength between the steel cord and the cover rubber can be increased, and a tire with excellent durability can be produced. Examples of the cobalt compound include, for example, cobalt alone, cobalt chloride, cobalt salt of organic acid, cobalt salt of inorganic acid, and the like, with cobalt salt of organic acid being preferred. These cobalt compounds can be used alone, or two or more of them can be used in combination. The cobalt organic acid salt is suitable for promoting adhesion between the plating layer of the steel cord and the rubber composition and for preventing plating components from leaching into the rubber composition during hygroscopic thermal deterioration. The number of carbon atoms of organic acids forming the cobalt organic acid compound is preferably 12 or more and 24 or less, and more preferably 14 or more and 22 or less. Specific examples of the cobalt organic acid salt include, for example, cobalt stearate, cobalt naphthenate, cobalt neodecanoate, cobalt trosinate, cobalt versarate, cobalt salt of tall oil fatty acids, cobalt oleate, cobalt linoleate, cobalt linolenate, cobalt palmitate, and the like. Furthermore, the cobalt salt of organic acid can be a complex salt (for example, cobalt boron 3-neodecanoate) in which some of the organic acids are replaced by boric acid. Examples of cobalt salts of inorganic acid include, for example, cobalt sulfate, cobalt nitrate, cobalt phosphate, cobalt chromate, and the like. The content of a cobalt element based on 100 parts by mass of the rubber component is preferably 2.85 × 10-3 parts by mass or less, more preferably 2.5 × 10-3 parts by mass or less, even more preferably 2.0 × 10-3 parts by mass or less, even more preferably 1.0 × 10-3 parts by mass or less, or may be 0 parts by mass. <Andere Verbindungsmittel> The rubber composition according to the present embodiment may, for example, in addition to the components described above, suitably include bonding agents that are conventionally and commonly used in the tire industry, such as a plasticizing agent, a vulcanized rubber particle, wax, an antioxidant, stearic acid, zinc oxide, a vulcanizing agent and a vulcanization accelerator, and the like. A plasticizer is a material that imparts plasticity to a rubber component and includes both liquid and solid plasticizers at 25°C. Examples of plasticizers include resin components, oils, liquid rubber, ester-based plasticizers, and the like. These plasticizers can be derived from mineral resources such as petroleum, natural gas, and the like; derived from biomass; or derived from naphtha recycled from a rubber or non-rubber product.Furthermore, low molecular weight hydrocarbon components obtained by pyrolyzing used tires or products containing various components, and by extracting them from the pyrolysate, can be used as plasticizers. These plasticizers can be used individually, or two or more can be used in combination. (resin component) The rubber composition according to the present embodiment may include a resin component. The resin component that may be used in the present embodiment is not particularly restricted, and any resin commonly used in the tire industry may be used. Examples include, for instance, a C9-based resin, a C5-based resin, a C5 / C9-based resin, a dicyclopentadiene-based resin, an aromatic vinyl-based resin, a coumaron-based resin, an indene-based resin, a terpene-based resin, a rosin-based resin, a phenol-based resin, and the like. These resin components may be used individually, or two or more of them may be used in combination. Each resin component may also be used individually, or any two or more of them may be used in combination. <<Harz auf C9-Basis> > A "C9-based resin" refers to a resin obtained by polymerizing C9 fractions and can be a polymer obtained by polymerizing a C9 fraction alone, or a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with a C9 fraction is called a DCPD / C9 resin. Furthermore, a C9-based resin can be one obtained by hydrogenating or modifying it. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumaron, indene, methylindene, dicyclopentadiene, and the like. Examples of C9-based resins include those commercially available from BASF, Zeon Corporation, ENEOS Corporation, etc. <<Harz auf C5-Basis> > A "C5-based resin" refers to a resin obtained by polymerizing C5 fractions, and can be one obtained by hydrogenating or modifying them. Examples of C5 fractions other than dicyclopentadiene include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, piperylene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, and the like. Examples of C5-based resins that can be used include those commercially available from STRUKTOL, Zeon Corporation, ENEOS Corporation, etc. <<Harz auf C5 / C9-Basis> > A "C5 / C9-based resin" refers to a resin obtained by copolymerizing the C5 and C9 fractions, and can also be one obtained by hydrogenation or modification thereof. Examples of C5 / C9-based resins include those commercially available from Tosoh Corporation, Zibo Luhua Hongjin New Material Group Co., Ltd., etc. <<Harz auf Dicyclopentadien-Basis> > A "dicyclopentadiene-based resin" refers to a resin that contains cyclopentadiene (CPD) and / or dicyclopentadiene (DCPD) as the predominant monomer component and may be one obtained by hydrogenation or modification thereof. Examples of dicyclopentadiene-based resins include polymers obtained by polymerizing only dicyclopentadiene as a monomer, copolymers obtained by copolymerizing dicyclopentadiene with the C9 fraction (DCPD / C9 resin), and similar formulations. Examples of dicyclopentadiene-based resins that can be used include those commercially available from Exxon Mobil Corporation, ENEOS Corporation, Zeon Corporation, Maruzen Petrochemical Co., Ltd., etc. <<Aromatisches Harz auf Vinyl-Basis> > An “aromatic vinyl-based resin” refers to a resin that incorporates an aromatic vinyl compound, such as styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, and the like, as a monomer component with the highest concentration, and may be one obtained by hydrogenation or modification thereof. A homopolymer of α-methylstyrene or styrene, or a copolymer of α-methylstyrene and styrene, is preferred as the aromatic vinyl-based resin, and a copolymer of α-methylstyrene and styrene is further preferred because it is economical, easy to process, and has excellent heat generation properties. Examples of commercially available aromatic vinyl-based resins include those from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. <<Harz auf Cumaron-Basis> > A "coumaron-based resin" refers to a resin that includes coumaron as a monomer component and may be one obtained by hydrogenating or modifying it. Examples of preferred coumaron-based resins include a coumaron resin that is a polymer containing only coumaron as a monomer component, a coumaron-indene resin that is a copolymer containing coumaron and indene as monomer components, a coumaron-indene-styrene resin that is a copolymer containing coumaron, indene, and styrene as monomer components, and the like. Examples of suitable coumaron-based resins include those commercially available from Rutgers Chemicals, Nitto Chemical Co., Ltd., Mitsui Chemicals, Inc., etc. <<Harz auf Inden-Basis> > An "indene-based resin" refers to a resin that includes indene as a monomer component and can be one obtained by hydrogenating or modifying it. Examples of indene-based resins include a coumaron-indene resin, which is a copolymer containing coumaron and indene as monomer components; a coumaron-indene-styrene resin, which is a copolymer containing coumaron, indene, and styrene as monomer components; and similar resins. Examples of indene-based resins that can be used include those commercially available from Rutgers Chemicals, Nitto Chemical Co., Ltd., Mitsui Chemicals, Inc., etc. <<Harz auf Terpen-Basis> > A "terpene-based resin" refers to a resin that incorporates a terpene compound, such as α-pinene, β-pinene, limonene, dipentene, and the like, as a monomer component, and may be one obtained by hydrogenation or modification thereof. Preferred examples of terpene-based resins include a polyterpene resin, which is a polymer comprising only one or more of the terpene compounds as monomer components; an aromatically modified terpene resin, which is a copolymer comprising the terpene compound and an aromatic compound as monomer components; a terpenophenolic resin, which is a copolymer comprising the terpene compound and a phenolic compound as monomer components; and the like. Examples of aromatic compounds used as monomer components for aromatically modified terpene resins include styrene, α-methylstyrene, vinyltoluene, divinyltoluene, and the like.Examples of phenolic compounds used as monomer components for terpene phenolic resin include phenol, bisphenol A, cresol, xylenol, and the like. Terpene-based resins that can be used include those commercially available from companies such as Yasuhara Chemical Co., Ltd., Arakawa Chemical Industries, Ltd., and Nippon Terpene Chemicals, Inc. <<Harz auf Kolophonium-Basis> > A "rosin-based resin" refers to a resin comprising a rosin acid compound, such as abietic acid, neoabietic acid, palustric acid, isopimaric acid, and the like, and may be one obtained by hydrogenation or modification thereof. Examples of rosin-based resins include, but are not limited to, natural resin rosin, rosin-modified resins obtained by modifying natural resin rosin through hydrogenation, disproportionation, dimerization, esterification, etc. Examples of rosin-based resins include those commercially available from Harima Chemicals Group, Inc., Arakawa Chemical Industries, Ltd., IREC Co., Ltd., etc. <<Harz auf Phenol-Basis> > A "phenol-based resin" refers to a resin that incorporates a phenolic compound, such as phenol, cresol, and the like, as a monomer component, and may be one obtained by hydrogenation or modification thereof. Examples of phenol-based resins include, but are not limited to, phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, oil-modified phenol-formaldehyde resins, terpene phenol resins, and the like. Examples of phenol-based resins include those commercially available from Sumitomo Bakelite Co., Ltd., DIC Corporation, ASAHI YUKIZAI CORPORATION, etc. The content of a resin component, when combined, based on 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, but is not specifically limited to these values. Furthermore, the content is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, and even more preferably less than 10 parts by mass. (Oil) Examples of oils include mineral oils, vegetable oils, animal oils, and the like. Furthermore, from a life cycle assessment perspective, one can also be used that is obtained by refining used oil after use in a rubber mixer or engine, or used cooking oil from a restaurant. The oils can be used individually, or two or more can be used in combination. In this description, "mineral oil" refers to oil derived from mineral resources such as petroleum, natural gas, and the like. Examples of mineral oil include paraffinic oils (mineral oils), naphthenic oils, aromatic oils, and the like. Specific examples of mineral oils include, for example, Mild Extracted Solvate (MES), Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Treated Residual Aromatic Extract (TRAE), Residual Aromatic Extract (RAE), and the like. Additionally, as an environmental measure, oils that each have a low content of a polycyclic aromatic compound (PCA) may be used. Examples of oils that each have a low content of PCA include MES, TDAE, heavy naphthenic oil, and the like. The mineral oil may be used alone, or two or more may be used in combination. In this description, examples of vegetable oils include, for instance, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, Japan wax, and the like. Furthermore, examples of vegetable oils also include refined oils obtained by refining the oils described above (salad oil, etc.).), a transesterified oil obtained by transesterifying the oil described above, a hydrogenated oil obtained by hydrogenating the oil described above, a thermally polymerized oil obtained by thermally polymerizing the oil described above, an oxidized polymerized oil obtained by oxidizing the oils described above, a used cooking oil obtained by restoring what has been used as an edible oil, etc., and the like. Furthermore, the vegetable oil may be liquid or solid at 25 °C. The vegetable oil may be used alone, or two or more of them may be used in combination. The vegetable oil according to the present embodiment preferably comprises acylglycerol and further preferably triacylglycerol. In this description, acylglycerol also refers to a compound in which a hydroxyl group of glycerol and a fatty acid are ester-bound. The acylglycerol is not specifically restricted and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a multimer that is a trimer or higher. Additionally, acylglycerol that is a dimer or higher may be obtained by thermal polymerization, oxidative polymerization, or the like. Furthermore, the acylglycerol may be liquid or solid at 25 °C. Whether the rubber composition includes the acylglycerol described above can be verified by 1H NMR measurement, but is not particularly limited to this. For example, a heavy chloroform into which a rubber composition containing triacylglycerol is immersed at 25 °C for 24 hours and then removed is subjected to 1H NMR measurement at room temperature, and signals near 5.26 ppm, near 4.28 ppm, and near 4.15 ppm are observed under a condition that a signal from tetramethylsilane (TMS) is set to 0.00 ppm. It is suggested that these signals are derived from hydrogen atoms bonded to carbon atoms adjacent to oxygen atoms of the ester group. Furthermore, "near" in this paragraph is intended to be a range of ±0.10 ppm. The fatty acid described above is not particularly restricted and can be either an unsaturated or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids, such as oleic acid, and the like; and polyunsaturated fatty acids, such as linoleic acid, linolenic acid, and the like. Furthermore, examples of saturated fatty acids include butyric acid, lauric acid, and the like. The desired fatty acid, as described above, is one with few double bonds, meaning a saturated or monounsaturated fatty acid, and oleic acid is preferred. A vegetable oil containing such a fatty acid could be, for example, a saturated or monounsaturated fatty acid, or a refined vegetable oil obtained through transesterification or similar processes. Furthermore, to produce a vegetable oil containing such a fatty acid, a plant can be improved through selective breeding, gene combination, genome editing, or similar methods. Vegetable oils that can be used include, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo KK, ENEOS Corporation, Olisoy, H&R Group, HOKOKU Corporation, Fuji Kosan Co., Ltd., The Nisshin Oillio Group, etc. Examples of animal oils include fish oils, beef tallow, whale oils, oleyl alcohol derived from them, and the like. The oil content, when combined, based on 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, but is not particularly limited thereto. Furthermore, the content is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, even more preferably less than 15 parts by mass, and particularly preferably less than 10 parts by mass. Liquid rubber is not particularly restricted as long as it is a polymer in a liquid state at 25 °C. Examples include liquid butadiene rubber (liquid BR), liquid styrene-butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene-isoprene rubber (liquid SIR), liquid farnesene rubber, and the like. These liquid rubbers can be used individually, or two or more of them can be used in combination. Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), di(2-ethylhexyl) azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), and the like. Ester-based plasticizers can be used alone, or two or more can be used in combination. The content of a plasticizing agent based on 100 parts by mass of the rubber component (a total amount of all plasticizing agents when used in combination) is, from the perspective of the effects of the present invention, preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the content is preferably less than 40 parts by mass, more preferably less than 30 parts by mass, even more preferably less than 20 parts by mass, and particularly preferably less than 10 parts by mass. The vulcanized rubber particle is a particle made from vulcanized rubber. Specifically, a rubber powder specified in JIS K 6316:2017, and similar materials, can be used. Recycled rubber powder produced from a powdered end-of-life tire or similar material is preferred from both an environmental and cost perspective. The vulcanized rubber particle can be used individually, or two or more particles can be used in combination. The vulcanized rubber particle is not particularly restricted and can be an unmodified vulcanized rubber particle or a modified vulcanized rubber particle. Examples of commercially available vulcanized rubber products include those manufactured by Lehigh Technologies, Muraoka Rubber Reclaiming Co., Ltd., etc. The content of a vulcanized rubber particle, when bonded, based on 100 parts by mass of the rubber component, can, for example, be appropriately adjusted within a range of more than 1 part by mass and less than 80 parts by mass. The type of wax is not particularly restricted, and any wax commonly used in the tire industry may be suitable. Examples include mineral-based waxes, plant-derived waxes, and the like. Mineral-based waxes refer to waxes derived from mineral resources such as oil, natural gas, and the like. Plant-derived waxes refer to waxes derived from natural resources such as plants and the like. Mineral-based waxes are preferred. Examples of plant-derived waxes include rice bran wax, carnauba wax, candelilla wax, and the like. Examples of mineral-based waxes include paraffin wax, microcrystalline wax, a specially selected wax of these, and the like, with paraffin wax being preferred.Furthermore, according to the present embodiment, the wax should not contain stearic acid. For example, waxes commercially available from Ouchi Shinko Chemical Industry Co., Nippon Seiro Co., Ltd., PARAMELT, etc., can be used. The wax can be used alone, or two or more can be used in combination. The wax content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the perspective of improving the weather resistance of the rubber. Furthermore, from the perspective of preventing whitening of a tire due to blooming, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. Examples of the antioxidant include, but are not specifically limited to, a naphthylamine-based antioxidant such as phenyl-α-naphthylamine and the like; a diphenylamine-based antioxidant such as octylated diphenylamine, 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine and the like; an antioxidant based on p-phenylenediamine, such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD) and the like; an antioxidant based on quinoline, such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline and the like;A monophenol-based antioxidant, such as 2,6-di-t-butyl-4-methylphenol, styrenized phenol, and the like; a bisphenol-based, trisphenol-based, or polyphenol-based antioxidant, such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane and the like; and the like. Among these, the p-phenylenediamine-based antioxidant and the quinoline-based antioxidant are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline are further preferred. Commercially available products may include, for example, those manufactured by Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ouchi Shinko Chemical Industry Co., Flexsys, etc. The antioxidant can be used alone, or two or more of them can be used in combination. The content of an antioxidant, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, with regard to the ozone crack resistance of a rubber. Furthermore, with regard to abrasion resistance and wet adhesion performance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. The stearic acid content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and still more preferably 1.5 parts by mass or more, from the point of view of processability. Furthermore, from the point of view of vulcanization rate, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. The zinc oxide content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the point of view of processability. Furthermore, from the point of view of abrasion resistance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. Sulfur is suitable for use as a vulcanizing agent. Suitable forms of sulfur include powdered sulfur, oil-processing sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and the like. When combined as a vulcanizing agent, the sulfur content, based on 100 parts by mass of the rubber component, is preferably 0.1 parts by mass or more, further preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and particularly preferably 0.7 parts by mass or more, to ensure a sufficient vulcanization reaction. Furthermore, to prevent deterioration, it is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, and particularly preferably 2.5 parts by mass or less. Additionally, when an oil-containing sulfur is used as the vulcanizing agent, the vulcanizing agent content is defined as the total content of pure sulfur contained in the oil-containing sulfur. A well-known organic crosslinking agent can also be used as a vulcanizing agent other than sulfur. While the choice of organic crosslinking agent is not particularly limited, as long as it can form a crosslinking chain other than polysulfide bonds, examples of organic crosslinking agents include alkylphenol-sulfur chloride condensate, sodium hexamethylene 1,6-bisthiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, dicumyl peroxide, and the like. These organic crosslinking agents can include those commercially available from Taoka Chemical Co., Ltd., LANXESS, Flexsys, etc. Examples of vulcanization accelerators include, but are not limited to, for example, a sulfenamide-based vulcanization accelerator, a thiazole-based vulcanization accelerator, a guanidine-based vulcanization accelerator, a thiuram-based vulcanization accelerator, a thiourea-based vulcanization accelerator, a dithiocarbamic acid salt-based vulcanization accelerator, an aldehyde-amine-based vulcanization accelerator, an aldehyde-ammonia-based vulcanization accelerator, an imidazoline-based vulcanization accelerator, a xanthate-based vulcanization accelerator, caprolactam disulfide, and the like. These vulcanization accelerators can be used alone, or two or more of them can be used in combination.Among these, one or more vulcanization accelerators selected from the group consisting of a sulfenamide-based vulcanization accelerator, a thiazole-based vulcanization accelerator, and a guanidine-based vulcanization accelerator are preferred, given that the desired effects can be obtained more appropriately. Examples of sulfenamide-based vulcanization accelerators include, for example, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), and the like. TBBS and CBS are preferred among these. Examples of thiazole-based vulcanization accelerators include, for example, 2-mercaptobenzothiazole (MBT) or its salt, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, and the like. MBTS and MBT are preferred. Examples of guanidine-based vulcanization accelerators include, for example, 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatechol borate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, 1,3-di-o-cumenyl-2-propionylguanidine, and the like. DPG is the preferred compound. The content of a vulcanization accelerator, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and even more preferably 1.0 parts by mass or more, to ensure a sufficient vulcanization rate. Furthermore, the content of the vulcanization accelerator, to suppress blooming, is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. [Production of rubber compound and tires] The rubber composition according to the present embodiment can be produced by a known method. It can be produced, for example, by kneading the respective components described above using a rubber kneading machine, such as an open roller, a closed-type kneader (a Banbury mixer, a kneader, and the like), and the like. The kneading step includes, for example, a basic kneading step involving the kneading of bonding agents and additives other than a vulcanizing agent and a vulcanization accelerator; and a final kneading step (F-kneading) involving the addition of the vulcanizing agent and the vulcanization accelerator to the kneaded product obtained in the basic kneading step, and the kneading of this product. Furthermore, the basic kneading step can also be subdivided into several steps if required. Examples of kneading conditions include, but are not specifically limited to, for example, a process of kneading at a delivery temperature of 150 °C to 170 °C for 3 to 10 minutes for the basic kneading step and kneading at 70 °C to 110 °C for 1 to 5 minutes for the final kneading step. The tire according to the present embodiment can be produced by a conventional method using the steel cord and sponge element described above. That is, a steel cord is covered using an unvulcanized rubber compound, corresponding to a cover rubber obtained by the method described above, thereby obtaining a layer, as a steel cord-rubber complex, which forms a belt layer. Furthermore, this, together with a tread section and other tire elements, is placed on a tire forming machine and formed by a conventional method to create an unvulcanized tire. This unvulcanized tire is then heated and pressurized in a vulcanizing machine, thus producing a tire.Examples of vulcanization conditions include, but are not limited to, for example, a process of vulcanizing at 150°C to 200°C for 10 to 30 minutes. A sponge element is bonded to it using double-sided adhesive tape in a state where the sponge element is curved along the inner surface of a tire cavity. <anwendung> Although the tire according to the present embodiment can be used as a general-purpose tire, such as a tire for a passenger car, a tire for a truck / bus, and a motorcycle, it can also be used as a tire for an electric car, a tire for a hybrid car, a tire for a plug-in hybrid car, or the like. Furthermore, the term "passenger car tire" refers to a tire intended for mounting on a four-wheeled vehicle with a maximum load capacity of 1000 kg or less. Additionally, the tire according to the present embodiment can be used as an all-season tire, a summer tire, or a winter tire, such as a studless tire, and the like. EXAMPLES Examples considered preferred for implementing the present invention (examples) are described below, although the scope of protection of the present invention is not limited to these examples. Results calculated on the basis of the evaluation methods described below, taking into account a tire forming a basic structure as shown in Fig. 1 and having specifications shown in the following descriptions and tables, are shown in Tables 2 to 5. Various chemicals used in examples and comparisons are shown collectively below. <schwammelement> Sponge element 1: Ether-based polyurethane foam, produced at production example 1, described below (density D: 9 kg / m³) Sponge element 2: Ether-based polyurethane foam, manufactured by MARUSUZU Corporation (model number: E-16, density D: 15 kg / m³) Sponge element 3: Ether-based polyurethane foam, manufactured by ACHILLES CORPORATION (model number: PD, density D: 25 kg / m³) <deckkautschuk> NR: TSR 20 Carbon Black: Show Black N330, manufactured by Cabot Japan KK (N2SA: 75 m2 / g, average primary particle size: 30 nm) Silicon Dioxide: Ultrasil VN3, manufactured by Evonik Industries AG (N2SA: 175 m2 / g, average primary particle size: 18 nm) Heat Curing Resin: SUMILITERESIN PR-12686E, manufactured by SUMITOMO BAKELITE CO., LTD. (Cashew nut oil modified phenolic resin, softening point: 100 °C) Curing Agent: SUMIKANOLE 507AP, manufactured by Taoka Chemical Co., Ltd. (Modified etherified methylolmelamine resin) Cobalt compound: Cost-F, manufactured by DIC Corporation (cobalt stearate) Zinc oxide: Zinc oxide No. 1, manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: M95, manufactured by NIPPON KANRYU INDUSTRY CO., LTD. (insoluble sulfur) Vulcanization accelerator: Nocceler DZ, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N,N-Dicyclohexyl-2-benzothiazolylsulfenamide (DCBS)) Production Example 1: Production of Sponge Element 1. Polyol (GP3000, manufactured by SANYO CHEMICAL INDUSTRIES, LTD.), water (ion-exchanged water), a catalyst (33LV, manufactured by SANKYO AIR PRODUCTS CO., LTD., MRH110, manufactured by JOHOKU CHEMICAL CO., LTD.), and a surfactant (SF2961, manufactured by Dow Corning Toray Silicone Corporation) are mixed in a predetermined ratio using a hand mixer. Then, predetermined polyisocyanate (T-80, manufactured by Nippon Polyurethane Industry Co., Ltd., MR200, manufactured by Nippon Polyurethane Co., Ltd.) is added, and this mixture is loaded into a foam box, allowing it to foam and then harden to form Sponge Element 1. (Examples and comparative examples) According to the compound formulations shown in Table 1, using a closed 1.7-liter Banbury mixer, all chemicals except sulfur and a vulcanization accelerator are kneaded for 5 minutes until a discharge temperature of 160 °C is reached to obtain a kneaded product. Next, using an open twin-screw mixer, the vulcanizing agent and the vulcanization accelerator are added to the kneaded product, and the mixture is kneaded for 4 minutes until the temperature reaches 105 °C to obtain an unvulcanized rubber composition. Using the resulting unvulcanized rubber composition, steel cords are coated to form a layer, as a steel cord-rubber complex, which constitutes a belt layer.These are mounted on a tire forming machine along with a tread section and other tire elements to produce an unvulcanized tire, and the unvulcanized tire is vulcanized at 170 °C, yielding each of the test tires listed in Tables 2 to 5. A sponge element is bonded to this using double-sided adhesive tape in a state where the sponge element is curved along an inner cavity surface of the tire. Here, the steel cord has a ternary plating layer, with an average plating thickness of 0.19 µm and a plating composition of 68 wt% Cu, 28 wt% Zn, and 4 wt% Co. <brennstoffeffizienz> Each test tire is mounted on a standardized rim, an internal pressure is set to 230 kPa, and rolling resistance is measured using a rolling resistance tester. A load is applied that is equal to or less than a standardized load. The rolling resistance of the test tire when driven at a speed of 80 km / h under these conditions is measured, and the inverse of this value is expressed as an index, with 100 being the equivalent of 100. The results show that the higher the index, the lower the rolling resistance and the better the fuel efficiency. <Haltbarkeit von Schwammelement> Each test tire is mounted on a standardized rim, an internal pressure is set to 230 kPa, and the durability of a sponge element is assessed using a drum tester. A load is applied equal to or greater than a standardized load. The test tire is then driven at a speed of 80 km / h under controlled conditions, and the distance traveled before the sponge element and a surrounding component are damaged is measured. The results are expressed as an index, with the value for comparison example 1 being 100. The results show that the higher the index, the better the durability. <gesamtleistung> The sum of a fuel efficiency index and a durability index is given as an overall performance index. Table 1 Composite quantity (mass parts) NR100100100 Soot 555555 Silicon dioxide 555 Thermosetting resin 3.0 3.0 3.0 Hardening agent 1.5 1.5 1.5 Cobalt compound - 0.030.5 Zinc oxide 101010 Sulfur 5, 65, 65, 6 Vulcanization accelerator1,21,21,2 Table 2 Table 2 Cover rubber A1 A2 A1 A1 A1 Configuration of steel cord 1 × 11 × 11 × 11 × 11 × 1 Cord diameter R (mm) 0.250, 250, 450, 250, 45 Number of arranged steel cords E: 8080808080 Bending stiffness Fr (g · cm) 5.55.555.55.555.5 Maximum load capacity WL (kg) 5295 295 299 389 38 Tire size 175 / 70R14 175 / 70R14 175 / 70R14 235 / 70R16 235 / 70R16 Sponge element 11111 Density D of sponge element (kg / cm³) 9.09.09.09.09.09.0 M (= R / WL × 10 4 )4, 74, 78, 52, 74, 8 D / M1, 91, 91, 13, 41, 9 D / E0, 110,110,110,110,11 D / Fr1, 641, 640, 161, 640,16 Fuel efficiency 112112130103112 Shelf life 117105125102116 Total output 229217255205228 Table 3 Table 3 Cover rubber A1A1A1A1A1 Configuration of steel cord 1 × 41 × 41 × 22 + 21 × 2 Cord diameter R (mm) 0.750, 750, 750, 750, 75 Number of arranged steel cords E: 6060609060 Bending stiffness Fr (g • cm) 55,555,541,245,241,2 Maximum load capacity WL (kg) 529938 5295 29938 Tire size 175 / 70R14 235 / 70R16 175 / 70R14 175 / 70R14 235 / 70R16 Sponge element 11111 Density D of sponge element (kg / cm³) 9.09.09.09.09.0 M (= R / WL × 10 4 )14,28,014,214,28.0 D / M0,61,10,60,61,1 D / E0,150,150,150,100,15 D / Fr0,160,160,220,200,22 Fuel efficiency 156128151151123 Shelf life 136121134138119 Total output 292249285289242 Table 4 Table 4 Cover rubber A1A1A1A1 Configuration of steel cord2 + 21 × 11 × 11 × 4 Cord diameter R (mm) 0.75 0.45 0.45 0.75 Number of arranged steel cords E: 90808060 Bending stiffness Fr (g • cm) 45.25, 55.55, 55.5 Maximum load capacity WL (kg) 938938938938 Tire size 235 / 70R16 235 / 70R16 235 / 70R16 235 / 70R16 Sponge element 1122 Density D of sponge element (kg / cm³) 9.09.015.015.0 M (= R / WL × 10 4 )8.04.84.88.0 D / M1,11,93,11,9 D / E0,100,110,190,25 D / Fr0,201,642,730,27 Fuel efficiency 123112112128 Shelf life 12310696104 Total output 246218208232 Table 5 Table 5 Cover rubber A1 A3 A1 A1 A1 Configuration of steel cord 1 × 11 × 11 × 11 × 11 × 1 Cord diameter R (mm) 0, 250, 250, 20, 250, 25 Number of arranged steel cords E: 8080808080 Bending stiffness Fr (g · cm) 5.55, 55.55, 55.5 Maximum load capacity WL (kg) 12241224938529938 Tire size: 265 / 70R17, 265 / 70R17, 235 / 70R16, 175 / 70R14, 235 / 70R16 Sponge element 11133 Density D of sponge element (kg / cm³) 9.09.09.025.025.0 M (= R / WL × 10 4 )2, 02,02, 14, 72, 7 D / M4,44,44,25,39,4 D / E0, 110, 110, 110, 310, 31 D / Fr1, 641, 641,644,554,55 Fuel efficiency 100 100 100 112 103 Shelf life 100751008482 Total output 200175 200196185 <Ausführungsformen> Examples of embodiments of the present invention are described below.[1] A tire comprising a belt layer and a sponge element on an inner surface of a tread section in a tire radial direction, wherein the belt layer comprises: a steel cord consisting of one to four filaments, and a cover rubber covering the steel cord, wherein the cover rubber is composed of a rubber composition comprising a rubber component, wherein a density D of the sponge element is less than 20 kg / m³, preferably 8.0 to 17 kg / m³, and wherein M is greater than 2.5, preferably greater than 3.0 and less than 20, further preferably greater than 4.0 and less than 15, and D / M is less than 7.0, preferably more than 0.3 and less than 5.0, further preferably more than 0.5 and less than 4.0, wherein M is defined as follows: M = R / WL × 10⁴, where R is a cord diameter in mm of the steel cord represents and represents the maximum load capacity in kg of the tire.[2] The tire of [1] above, wherein the steel cord has a 1 × 1 structure or a 1 × 4 structure. [3] The tire of [1] or [2] above, wherein D / E is less than 0.17, preferably more than 0.08 and less than 0.17, where E is the number of steel cords arranged per 50 mm in a tire width direction. [4] The tire of any of [1] to [3] above, wherein D / Fr is less than 1.7, preferably more than 0.10 and less than 1.4, where Fr is a bending stiffness in g • cm of the steel cord. [5] The tire of any of [1] to [4] above, wherein the content of a cobalt element based on 100 parts by mass of the rubber component in the rubber composition is 2.85 × 10⁻³ parts by mass or less. [6] The tire of one of [1] to [5] above, wherein D / M is less than 3.0, preferably more than 0.5 and less than 3.0.[7] The tire of one of [1] to [6] above, wherein the rubber composition comprises silicon dioxide.[8] The tire of one of [1] to [7] above, wherein the steel cord comprises a ternary plating layer composed of copper, zinc and cobalt. [9] The tire of one of [1] to [8] above, wherein the belt layer comprises a first belt layer and a second belt layer laminated on an outside of the first belt layer in the tire radial direction, and wherein b / a is 1.5 or more and preferably 1.5 to 4.5, wherein “a” represents a shortest distance between a steel cord of the second belt layer in a tire central section and a steel cord of the first belt layer, and “b” represents a shortest distance between a steel cord located at an outermost end of the second belt layer and the cord of the first belt layer.

[10] The tire of one of [1] to [9] above, wherein both the distance between the upper and lower surfaces of a first belt layer in a tire center section and a cord, and the distance between both the upper and lower surfaces of a second belt layer in the tire center section and a cord, are 0.14 mm or less, and preferably 0.03 to 0.14 mm.

[11] The tire of one of [1] to

[10] above, wherein the tire further comprises an electronic component.

[12] The tire of one of [1] to

[11] above, wherein the tire is a tire for an electric car, a tire for a hybrid car, or a tire for a plug-in hybrid car. REFERENCE MARK LIST 1 Tread section 5 First belt layer 6 Second belt layer 7 Belt layer 11 Tire 15 Tire cavity surface 31 Bead core 32 Sidewall 33 Bead section 34 Carcass 36 Belt 37 Recessed groove 39 Sponge element 61 Edge band 62 Solid band CL Tire equator plane 5A, 6A, 50 Steel cord 5B, 6B Top layer rubber 51 Filament QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature JP 2007-302203 A

[0002] EP 3427975 A

[0123] JP 6856781 B [0123, 0124]EP 3173251 A

[0124] JP 2009-2594 A

[0131] Cited non-patent literature Rubber Chemistry and Technology", Bd. 85, Nr. 3, Seiten 408 bis 449 (2012

[0123] A Comparison of Surface Morphology and Chemistry of Pyrolytic Carbon Blacks with Commercial Carbon Blacks, Powder Technology 160 (2005) 190-193

[0123] Akita Prefectural University Web Journal B / 2019, Bd. 6, S. 216-222

[0131] < / gesamtleistung> < / brennstoffeffizienz> < / deckkautschuk> < / schwammelement> < / anwendung> < / kobaltverbindung> < / kautschukkomponente> < / reifen> < / messverfahren> < / definitionen>

Claims

A tire comprising a belt layer and a sponge element on an inner surface of a tread section in a tire radial direction, wherein the belt layer comprises: a steel cord consisting of one to four filaments, and a cover rubber covering the steel cord, the cover rubber being composed of a rubber composition comprising a rubber component, wherein the density D of the sponge element is less than 20 kg / m³, and wherein M is greater than 2.5 and D / M is less than 7.0, where M is defined as follows: M = R / WL × 10⁴, where R represents a cord diameter in mm of the steel cord and WL represents a maximum load capacity in kg of the tire. Tires according to claim 1, wherein the steel cord has a 1 × 1 structure or a 1 × 4 structure. Tires according to claim 1 or 2, wherein D / E is less than 0.17, where E represents the number of steel cords arranged per 50 mm in a tire width direction. Tires according to any one of claims 1 to 3, wherein D / Fr is less than 1.7, where Fr represents a bending stiffness in g · cm of the steel cord. Tires according to any one of claims 1 to 4, wherein the content of a cobalt element based on 100 parts by mass of the rubber component in the rubber composition is 2.85 × 10-3 parts by mass or less. Tires according to any one of claims 1 to 5, wherein D / M is less than 3.

0. Tires according to any one of claims 1 to 6, wherein the rubber composition comprises silicon dioxide. Tires according to any one of claims 1 to 7, wherein the steel cord comprises a ternary plating layer composed of copper, zinc and cobalt. Tire according to any one of claims 1 to 8, wherein the belt layer comprises a first belt layer and a second belt layer laminated on an outside of the first belt layer in the tire radial direction, and wherein b / a is 1.5 or more, wherein “a” represents a shortest distance between a steel cord of the second belt layer in a tire central section and a steel cord of the first belt layer, and “b” represents a shortest distance between a steel cord located at an outermost end of the second belt layer and the cord of the first belt layer. Tires according to any one of claims 1 to 9, wherein both the distance between the upper and lower surfaces of a first belt layer in a tire center section and a cord, as well as the distance between the upper and lower surfaces of a second belt layer in the tire center section and a cord, is 0.14 mm or less. Tires according to any one of claims 1 to 10, wherein the tire further comprises an electronic component. Tires according to any one of claims 1 to 11, wherein the tire is a tire for an electric car, a tire for a hybrid car or a tire for a plug-in hybrid car.

Images