Patent Description:
For example, as described in Patent Document <NUM>, a tire having a carcass ply is known.

<CIT> discloses a pneumatic tire that can be manufactured according to the conventional method without requiring special tire manufacturing steps and without needing addition of material members and production steps, and having excellent rolling resistance and wet properties, and having conductivity is to be provided. A pneumatic tire comprises a carcass having a ply which is turned back and locked around a bead core, a rim strip provided in a bead part, and a wing in which one edge thereof is contacted with the carcass and the other edge is exposed to the surface of a ground contact edge region of a tread part, wherein a covering rubber of a carcass ply, the rim strip and the wing are formed into a continuous conductive path by a conductive rubber material, only the conductive path is used as a conducting path of the tire, and members other than the conducting path are selected and used from a conductive rubber material or a nonconductive rubber material.

<CIT> discloses a pneumatic tire that has a carcass ply and a side wall rubber provided in outer sides of the carcass ply. The carcass ply has joint portions obtained by overlapping end portions of ply members so as to join. At least one of the joint portions is provided with a rubber tape. The rubber tape is interposed between the end portions of the ply members and is exposed to a surface of the carcass ply. A topping rubber of the carcass ply and the side wall rubber are formed by a nonconductive rubber. The rubber tape is formed by a conductive rubber. A conductive route getting to the rubber tape from a ground-contacting surface is formed in a tread portion. A conductive route getting to the rubber tape from an outer surface of a bead portion is formed in the bead portion.

<CIT> discloses a pneumatic tire comprising a carcass as a skeletal structure composed of at least one carcass ply extending toroidally between a pair of bead portions, at least one layer of a belt located on the outer side of the carcass in the tire radial direction of the crown portion. The tire is provided with a cushion rubber and a tread rubber forming a tread portion in turn on the outer side of the belt in the tire radial direction, and a composite fiber containing a conductive fiber and a non-conductive fiber is extended at least from the pair of bead portions to portions in contact with the cushion rubber or a pair of belt under cushions, so as to expose the composite fiber to both surfaces of the carcass at the outer and inner sides of the tire.

<CIT> discloses a vehicle pneumatic tire having a carcass with at least one carcass layer, the surface of which has a support made of electrically conductive material, and a method for manufacturing such a vehicle pneumatic tire. The object is to make available a vehicle pneumatic tire and a method for manufacturing same, the electrical conductivity of which tire is reliably ensured with simple means and simple structural design. The object is achieved in that the support is an electrically conductive rubber mixture and extends continuously on the surface of the carcass layer from an electrically conductive bead base as far as the superstructure and makes contact therewith. The method has the following steps: a) manufacturing the carcass layer, b) covering a surface of the carcass layer with a continuous support made of an electrically conductive rubber mixture, wherein the support in the finished vehicle pneumatic tire makes contact with an electrically conductive bead base and the superstructure.

In the tire, reduction of rolling resistance is required. In order to reduce the rolling resistance, for example, an amount of carbon contained in a carcass rubber in a carcass ply may be reduced. However, when the amount of carbon contained in the carcass rubber is reduced, the volume resistivity of the carcass rubber increases, and a conductive path from a bead portion to a tread surface portion may be blocked by the carcass ply. Therefore, it may be difficult for static electricity transmitted from a vehicle to the bead portion to be released from the tread surface portion to the ground.

One aspect of the present invention is made in view of the above circumstances, and an object thereof is to provide a tire having a structure in which static electricity from a vehicle is easily released to the ground regardless of conductivity of a carcass ply.

According to a first aspect of the present invention there is provided a tire as specified in claim <NUM>.

According to one aspect of the present invention, it is possible to provide a tire having a structure in which static electricity from a vehicle is easily released to the ground regardless of conductivity of a carcass ply.

Hereinafter, a tire according to an embodiment of the present invention will be described with reference to the drawings. Further, in the following drawings, a scale and a number of each structure may be different from a scale and a number of an actual structure in order to make each configuration easy to understand.

A Z-axis direction shown in each drawing is a direction parallel to a tire radial direction centered on a rotation axis of a tire <NUM>. In each drawing, the tire radial direction is an up-down direction. In a portion of the tire <NUM> shown in each drawing, a positive side in the Z-axis direction, that is, an upper side in each drawing is an outside in the tire radial direction, and a negative side in the Z-axis direction, that is, a lower side in each drawing is an inside in the tire radial direction.

A Y-axis direction shown in each drawing is a direction parallel to a tire width direction. In <FIG> and <FIG>, the tire width direction is a left-right direction. In the following description, for a certain object, a side closer to a tire equatorial portion CL in the tire width direction is referred to as an "inside in the tire width direction", and a side far from the tire equatorial portion CL in the tire width direction is referred to as an "outside in the tire width direction". The tire equatorial portion CL is a center in the tire width direction of the tire <NUM> of the present embodiment. In a portion of the tire <NUM> shown in each drawing, a negative side in the Y-axis direction, that is, for example, a right side in <FIG> and <FIG> is an inside in the tire width direction, and a positive side in the Y-axis direction, that is, for example, a left side in <FIG> and <FIG> is an outside in the tire width direction.

Further, a circumferential direction around a central axis (not shown) of the tire <NUM> is referred to as a tire circumferential direction. The X-axis direction shown in each drawing is a direction orthogonal to both the Z-axis direction and the Y-axis direction, and is the circumferential direction in the cross section of the tire <NUM> shown in each drawing.

<FIG> shows a portion of the tire <NUM> located on one side of the tire equatorial portion CL in the tire width direction in a cross section of a portion of the tire <NUM> in the tire circumferential direction. In the cross section of the portion of the tire <NUM> in the tire circumferential direction, a portion located on the other side of the tire equatorial portion CL in the tire width direction is disposed symmetrically with the portion shown in <FIG> in the tire width direction in a state where the tire equatorial portion CL is interposed therebetween. In the following description, the portion of the tire <NUM> shown in <FIG> will be described, and the portion of the tire <NUM> located on the other side of the tire equatorial portion CL in the tire width direction may be omitted.

As shown in <FIG>, the tire <NUM> of the invention includes a tread portion <NUM>, a sidewall portion <NUM>, and a bead portion <NUM>.

The tread portion <NUM> is disposed outside the bead portion <NUM> in the tire radial direction, and is located at an outer end portion of the tire <NUM> in the tire radial direction. The tread portion <NUM> has an annular shape extending in the tire circumferential direction. The tread portion <NUM> has a tread surface portion 11a which is a ground contact surface of the tire <NUM>. The tread surface portion 11a is a portion of an outer surface of the tread portion <NUM> in the tire radial direction.

For example, the tread surface portion 11a is the ground contact surface of the tread portion <NUM> in a state where the tire <NUM> is mounted on a standard rim specified in "JATMA Year Book", and the tire <NUM> is filled with the internal pressure (hereinafter, referred to as a specified internal pressure) of <NUM>% of an air pressure (maximum air pressure) corresponding to a maximum load capacity (internal pressure - bold load of load capacity correspondence table) in an applicable size and ply rating in "JATMA Year Book" so that a maximum load corresponding to the maximum load capacity is applied.

For example, when the tire <NUM> is produced or used in a region other than Japan, the tread surface portion 11a is a ground contact surface of the tread portion <NUM> of the tire <NUM> based on an industrial standard (for example, "TRA Year Book" in the United States, "ETRTO Standard Manual" in Europe, or the like) applied to the region other than Japan.

The sidewall portion <NUM> extends inward in the tire radial direction from an outer end portion of the tread portion <NUM> in the tire width direction. The sidewall portion <NUM> connects the outer end portion of the tread portion <NUM> in the tire width direction and the bead portion <NUM>.

The bead portion <NUM> is connected to an inner end portion of the sidewall portion <NUM> in the tire radial direction. A bead core <NUM> is provided in the bead portion <NUM>. More specifically, the bead core <NUM> is embedded in the bead portion <NUM>.

The tire <NUM> includes a carcass layer <NUM> which serves as a skeleton. For example, the tire <NUM> is formed by assembling a first chafer portion <NUM>, a tire body <NUM>, a belt layer <NUM>, and a belt reinforcing layer <NUM> to the carcass layer <NUM>. The carcass layer <NUM> is provided so as to extend over the tread portion <NUM>, the sidewall portion <NUM>, and the bead portion <NUM>. The carcass layer <NUM> has an annular shape extending in the tire circumferential direction. As shown in <FIG> and <FIG>, the carcass layer <NUM> has a carcass ply <NUM> and a conductive portion <NUM>.

The carcass ply <NUM> covers at least a portion of the bead core <NUM> around a core axis of the bead core <NUM>. The carcass ply <NUM> in the present embodiment extends from the tread portion <NUM> to the bead portion <NUM> via the sidewall portion <NUM> and is folded outward in the tire width direction around the bead core <NUM>. The carcass ply <NUM> has an annular shape extending in the tire circumferential direction. As shown in <FIG>, the carcass ply <NUM> has a carcass rubber 51a and a plurality of ply cords 51b. The carcass ply <NUM> is formed by embedding the plurality of ply cords 51b in the carcass rubber 51a.

In the following description, an inner surface of surfaces of the carcass ply <NUM> is referred to as a "first surface", and an outer surface of the surfaces of the carcass ply <NUM> is referred to as a "second surface". In the tread portion <NUM>, the first surface is a surface of the surfaces of the carcass ply <NUM> located inside in the tire radial direction. In the tread portion <NUM>, the second surface is a surface of the surfaces of the carcass ply <NUM> located outside in the tire radial direction.

In the present embodiment, the loss tangent tan δ of the carcass rubber 51a is relatively small. The smaller the amount of carbon contained in the carcass rubber 51a, the smaller the loss tangent tan δ. The smaller the loss tangent tan δ of the carcass rubber 51a, the smaller the rolling resistance of the tire <NUM>. In the present embodiment, the carcass rubber 51a is relatively difficult to conduct electricity. As a result, the conductivity of the carcass ply <NUM> in the present embodiment is relatively low.

Each of the plurality of ply cords 51b extends from the tread portion <NUM> to the bead portion <NUM> via the sidewall portion <NUM> and are folded outward in the tire width direction around the bead core <NUM> in a state of being embedded in the carcass rubber 51a. The plurality of ply cords 51b are disposed at intervals in the tire circumferential direction. For example, the ply cord 51b is an organic fiber cord or the like.

The conductive portion <NUM> is provided on the outer surface, that is, on the second surface, of the carcass ply <NUM>. As shown in <FIG>, the conductive portion <NUM> extends along the carcass ply <NUM>. In the tread portion <NUM>, the conductive portion <NUM> is located outside the carcass ply <NUM> in the tire radial direction. In the present embodiment, the conductive portion <NUM> extends from the tread portion <NUM> to at least the inside of the bead core <NUM> in the tire radial direction. In the present embodiment, the conductive portion <NUM> extends from the tread portion <NUM> to the bead portion <NUM> via the sidewall portion <NUM>, is folded outward in the tire width direction around the bead core <NUM>, and extends to the outside of the bead core <NUM> in the tire width direction.

An outer end portion in the tire radial direction of a portion of the conductive portion <NUM> folded around the bead core <NUM> is disposed at the same position in the tire radial direction as an outer end portion in the tire radial direction of a portion of the carcass ply <NUM> folded around the bead core <NUM>. At least a portion of the conductive portion <NUM> is located between the carcass ply <NUM> and the bead core <NUM>. In the present embodiment, a portion of the conductive portion <NUM> located inside the bead core <NUM> in the tire radial direction and portions of the conductive portion <NUM> located on both sides of the bead core <NUM> in the tire width direction are located between the carcass ply <NUM> and the bead core <NUM>. In the present embodiment, the conductive portion <NUM> is connected to a conductive rubber portion <NUM> to be described later. As shown in <FIG>, on the inside of the bead core <NUM> in the tire radial direction, the plurality of conductive portions <NUM> are attached to the outer surface of the carcass rubber 51a in the tire radial direction.

In the present embodiment, the conductive portion <NUM> is a thread member containing a metal. For example, the conductive portion <NUM> is a conductive thread in which a metal fiber such as stainless steel is wound around an organic fiber. The plurality of conductive portions <NUM> are disposed at intervals in the tire circumferential direction.

<FIG> shows, as an example, a state in which the plurality of conductive portions <NUM> are located outside the plurality of ply cords 51b in the tire radial direction, but the present invention is not limited to this. A positional relationship between the plurality of conductive portions <NUM> and the plurality of ply cords 51b in the tire circumferential direction is not particularly limited. That is, in <FIG>, the position of the conductive portion <NUM> in the left-right direction may deviate from the position of the ply cord 51b in the left-right direction. Further, the number of the conductive portions <NUM> and the number of the ply cords 51b may be the same or different.

The conductive portion <NUM> has conductivity. The volume resistivity of the conductive portion <NUM> is smaller than the volume resistivity of the conductive rubber portion to be described later. In the present specification, "a member has conductivity" and "a member is relatively easy to conduct electricity" may mean that the volume resistivity of a member is low enough to allow static electricity from the vehicle to flow.

The first chafer portion <NUM> has conductivity. The first chafer portion <NUM> is a rubber member or a composite member of fibers and rubber. As shown in <FIG>, the first chafer portion <NUM> covers a portion of the carcass ply <NUM> provided in the bead portion <NUM> from inside in the tire radial direction and from both sides in the tire width direction. The portion of the carcass ply <NUM> provided in the bead portion <NUM> includes a portion of the carcass ply <NUM> that covers the bead core <NUM> from an inside in the tire radial direction and from both sides in the tire width direction. In the following description, the portion of the carcass ply <NUM> provided in the bead portion <NUM> is defined as a core covering portion <NUM>. The core covering portion <NUM> extends from the inside of the bead core <NUM> in the tire width direction to the outside of the bead core <NUM> in the tire width direction through the inside of the bead core <NUM> in the tire radial direction. The first chafer portion <NUM> has an annular shape extending in the tire circumferential direction.

The first chafer portion <NUM> has a radial covering portion <NUM> and widthwise covering portions <NUM> and <NUM>. The radial covering portion <NUM> is a portion that covers the core covering portion <NUM> of the carcass ply <NUM> from the inside in the tire radial direction. The radial covering portion <NUM> extends in the tire width direction. The widthwise covering portions <NUM> and <NUM> are portions that cover the core covering portion <NUM> of the carcass ply <NUM> from both sides in the tire width direction. The widthwise covering portion <NUM> extends from an outer end portion of the radial covering portion <NUM> in the tire width direction to the outside in the tire radial direction, and covers the core covering portion <NUM> from the outside in the tire width direction. The widthwise covering portion <NUM> extends from an inner end portion of the radial covering portion <NUM> in the tire width direction to the outside in the tire radial direction, and covers the core covering portion <NUM> from the inside in the tire width direction. The outer end portions of the widthwise covering portions <NUM> and <NUM> in the tire radial direction are located on an inner side in the tire radial direction than the outer end portion in the tire radial direction of the portion of the carcass ply <NUM> folded around the bead core <NUM>.

As shown in <FIG>, the tire body <NUM> has a tread rubber <NUM> and a sidewall rubber <NUM>.

The tread rubber <NUM> is a portion forming a portion of the tread portion <NUM>, and has an annular shape extending in the tire circumferential direction. The tread rubber <NUM> is provided outside the carcass layer <NUM> in the tire radial direction. The tread rubber <NUM> is connected to the carcass layer <NUM> via the belt layer <NUM> and the belt reinforcing layer <NUM>. In <FIG>, in order to show each portion schematically in an easy-to-understand manner, the carcass layer <NUM> is shown apart from the tread rubber <NUM>, the belt layer <NUM>, and the belt reinforcing layer <NUM>.

The tread rubber <NUM> has a tread under cushion <NUM>, a base layer <NUM>, a cap layer <NUM>, a mini side <NUM>, and an antenna rubber <NUM>.

The tread under cushion <NUM>, the base layer <NUM>, and the cap layer <NUM> are laminated in this order from the inside in the tire radial direction to the outside in the tire radial direction. An outer surface of the cap layer <NUM> in the tire radial direction constitutes the tread surface portion 11a. The mini side <NUM> is connected to outer end portions in the tire width direction of the laminated tread under cushion <NUM>, the base layer <NUM> and the cap layer <NUM>.

The antenna rubber <NUM> is embedded in the base layer <NUM> and the cap layer <NUM>. The antenna rubber <NUM> penetrates the base layer <NUM> and the cap layer <NUM> in the tire radial direction. An inner end portion of the antenna rubber <NUM> in the tire radial direction is connected to the outer surface of the tread under cushion <NUM> in the tire radial direction. An outer end portion of the antenna rubber <NUM> in the tire radial direction is exposed on the outer surface of the cap layer <NUM> in the tire radial direction, and forms a portion of the tread surface portion 11a. The antenna rubber <NUM> may extend intermittently, may extend continuously, or may be scattered in the tire circumferential direction.

The base layer <NUM>, the cap layer <NUM>, and the mini side <NUM> are relatively difficult to conduct electricity and have low conductivity. The tread under cushion <NUM> and the antenna rubber <NUM> are relatively easy to conduct electricity and have conductivity.

The sidewall rubber <NUM> is a portion forming a portion of the sidewall portion <NUM> and a portion of the bead portion <NUM>, and has an annular shape extending in the tire circumferential direction. The sidewall rubber <NUM> is provided outside the carcass layer <NUM> in the tire width direction. The sidewall rubber <NUM> is connected to the carcass layer <NUM>. The outer end portion of the sidewall rubber <NUM> in the tire radial direction is connected to the outer end portion of the tread rubber <NUM> in the tire width direction. In <FIG>, in order to show each portion schematically in an easy-to-understand manner, the sidewall rubber <NUM> and the carcass layer <NUM> are shown apart from each other, and the sidewall rubber <NUM> and the tread rubber <NUM> are shown apart from each other.

The sidewall rubber <NUM> has a sidewall rubber main body portion <NUM> and a second chafer portion <NUM>.

The sidewall rubber main body portion <NUM> is a portion forming a portion of the sidewall portion <NUM>. An outer end portion of the sidewall rubber main body portion <NUM> in the tire radial direction extends inward in the tire width direction and is located between the carcass layer <NUM> and the tread rubber <NUM>, the belt layer <NUM>, and the belt reinforcing layer <NUM>.

The second chafer portion <NUM> is a portion forming a portion of the bead portion <NUM>. The second chafer portion <NUM> is connected to an inner end portion of the sidewall rubber main body portion <NUM> in the tire radial direction. The second chafer portion <NUM> covers the core covering portion <NUM> of the carcass layer <NUM> from the outside in the tire width direction. The second chafer portion <NUM> is connected to the core covering portion <NUM> and the widthwise covering portion <NUM> of the first chafer portion <NUM> from the outside in the tire width direction. In addition, in <FIG> and <FIG>, in order to show each portion in an easy-to-understand manner, the second chafer portion <NUM> and the core covering portion <NUM> are shown apart from each other, and the second chafer portion <NUM> and the widthwise covering portion <NUM> are shown apart from each other.

The volume resistivity of a rubber material constituting the sidewall rubber main body portion <NUM> is different from the volume resistivity of a rubber material constituting the second chafer portion <NUM>. The sidewall rubber main body portion <NUM> is relatively difficult to conduct electricity. The second chafer portion <NUM> is relatively easy to conduct electricity and has conductivity.

In the present embodiment, the first chafer portion <NUM> and the second chafer portion <NUM> constitute a chafer portion <NUM>. That is, in the present embodiment, the tire <NUM> has the chafer portion <NUM> that covers at least a portion around the carcass ply <NUM>. In the present embodiment, the chafer portion <NUM> covers at least the inside of the core covering portion <NUM> in the tire radial direction and the outside of the core covering portion <NUM> in the tire width direction. The chafer portion <NUM> has conductivity. In the chafer portion <NUM>, the volume resistivity of the first chafer portion <NUM> and the volume resistivity of the second chafer portion <NUM> may be the same as each other or may be different from each other. In the present embodiment, the chafer portion <NUM> covers the inside of the core covering portion <NUM> in the tire radial direction and both sides of the core covering portion <NUM> in the tire width direction, and is connected to the core covering portion <NUM>. The chafer portion <NUM> is a portion that protects the carcass layer <NUM> from friction with a rim to which the tire <NUM> is attached.

The belt layer <NUM> is embedded in the tread portion <NUM>. The belt layer <NUM> is laminated on the outer side of the carcass layer <NUM> in the tire radial direction. The belt layer <NUM> is connected to the carcass ply <NUM> and the conductive portion <NUM>. The belt layer <NUM> is located between the tread rubber <NUM> and the carcass layer <NUM> in the tire radial direction. Although not shown, the belt layer <NUM> is formed by embedding a plurality of steel cords in a belt rubber. The belt rubber of the belt layer <NUM> is relatively easy to conduct electricity and has conductivity. As a result, the belt layer <NUM> has conductivity.

The belt reinforcing layer <NUM> is laminated on the outer side of the belt layer <NUM> in the tire radial direction. The belt reinforcing layer <NUM> is located between the tread rubber <NUM> and the belt layer <NUM> in the tire radial direction. An outer surface of the belt reinforcing layer <NUM> in the tire radial direction is connected to an inner surface of the tread under cushion <NUM> of the tread rubber <NUM> in the tire radial direction.

The belt reinforcing layer <NUM> is formed by, for example, winding a composite cord, which is made of rubber and nylon, around an outer peripheral portion of the belt layer <NUM> a plurality of times. The winding rolls of the composite cord constituting the belt reinforcing layer <NUM> are disposed to be separated from each other with gaps <NUM> in the tire width direction. Although not shown, in the gap <NUM> between the winding rolls of the belt reinforcing layer <NUM>, the tread under cushion <NUM> and the belt layer <NUM>, between which the belt reinforcing layer <NUM> is interposed in the tire radial direction, are connected to each other. The belt reinforcing layer <NUM> is relatively difficult to conduct electricity.

As shown in <FIG>, the conductive rubber portion <NUM> is provided in the bead portion <NUM>. The conductive rubber portion <NUM> is relatively easy to conduct electricity and has conductivity. The volume resistivity of the conductive rubber portion <NUM> is smaller than the volume resistivity of the carcass rubber 51a. For example, the volume resistivity of the conductive rubber portion <NUM> is smaller than the volume resistivity of the first chafer portion <NUM> and the volume resistivity of the second chafer portion <NUM>. For example, the volume resistivity of the conductive rubber portion <NUM> is different from the volume resistivity of other rubber materials constituting the bead portion <NUM>.

The volume resistivity of the conductive rubber portion <NUM> may be the same as the volume resistivity of the first chafer portion <NUM> and the volume resistivity of the second chafer portion <NUM>, or may be larger than the volume resistivity of the first chafer portion <NUM> and the volume resistivity of the second chafer portion <NUM>.

The conductive rubber portion <NUM> is provided between the carcass ply <NUM> and the bead core <NUM>. The conductive rubber portion <NUM> is disposed so as to penetrate the core covering portion <NUM> and extend from the inside of the core covering portion <NUM> to the outside of the core covering portion <NUM>. The conductive rubber portion <NUM> has an annular shape extending in the tire circumferential direction. The conductive rubber portion <NUM> has a first portion <NUM>, a second portion <NUM>, and a third portion <NUM>.

The first portion <NUM> is located inside the bead core <NUM> in the tire radial direction. That is, the first portion <NUM> is provided inside in the tire radial direction from the outer end portion of the bead core <NUM> in the tire radial direction. As a result, at least a portion of the conductive rubber portion <NUM> is provided inside in the tire radial direction from the outer end portion of the bead core <NUM> in the tire radial direction. The first portion <NUM> extends in the tire width direction. The first portion <NUM> is disposed so as to penetrate the carcass layer <NUM> in the tire radial direction. An outer end portion of the first portion <NUM> in the tire radial direction is in contact with the bead core <NUM>. An inner end portion of the first portion <NUM> in the tire radial direction is connected to the first chafer portion <NUM>. More specifically, the inner end portion of the first portion <NUM> in the tire radial direction is connected to the radial covering portion <NUM> of the first chafer portion <NUM>. As shown in <FIG>, the first portion <NUM> has a base portion (intervening portion) <NUM>, a penetrating portion (embedded portion) <NUM>, and a non-penetrating portion (embedded portion) <NUM>.

The base portion <NUM> is laminated on the outer side of the carcass ply <NUM> in the tire radial direction. The conductive portion <NUM> is embedded in the base portion <NUM>. As a result, the first portion <NUM> is connected to the conductive portion <NUM>. In the present embodiment, the base portion <NUM> corresponds to the intervening portion located between the bead core <NUM> and the carcass ply <NUM>.

The penetrating portion <NUM> extends inward in the tire radial direction from the base portion <NUM>. For example, a plurality of penetrating portions <NUM> are disposed in the tire circumferential direction. The penetrating portion <NUM> penetrates, in the tire radial direction, a portion of the carcass rubber 51a located between the ply cords 51b. In the present embodiment, the penetrating portion <NUM> divides the carcass rubber 51a in the tire circumferential direction. An inner end portion of the penetrating portion <NUM> in the tire radial direction is connected to the radial covering portion <NUM> of the first chafer portion <NUM>. The dimension of the penetrating portion <NUM> in the tire radial direction is larger than the dimension of the base portion <NUM> in the tire radial direction. The penetrating portion <NUM> penetrates the carcass ply <NUM> from the second surface to the first surface of the carcass ply <NUM>. That is, the penetrating portion <NUM> penetrates the carcass ply <NUM> in a thickness direction. As a result, the conductive rubber portion <NUM> penetrates the first surface and the second surface of the carcass ply <NUM>.

In the present embodiment, the penetrating portion <NUM> corresponds to the embedded portion embedded in the carcass ply <NUM>. More specifically, in the present embodiment, the penetrating portion <NUM> corresponds to a first embedded portion embedded in a portion of the carcass ply <NUM> located inside the bead core <NUM> in the tire radial direction. In the present embodiment, the penetrating portion <NUM>, which is the embedded portion, is located between the ply cords 51b. In the present specification, "the embedded portion is embedded in the carcass ply" includes that the embedded portion is embedded in the carcass rubber of the carcass ply. The penetrating portion <NUM>, which is the embedded portion in the present embodiment, is embedded in the carcass rubber 51a.

The non-penetrating portion <NUM> extends inward in the tire radial direction from the base portion <NUM>. The non-penetrating portion <NUM> is embedded in a portion of the carcass rubber 51a located between the ply cords 51b. An inner end portion of the non-penetrating portion <NUM> in the tire radial direction does not reach the radial covering portion <NUM>. That is, the non-penetrating portion <NUM> does not penetrate the carcass rubber 51a.

As described above, on the inside of the bead core <NUM> in the tire radial direction, the first portion <NUM> connects the conductive portion <NUM> and the first chafer portion <NUM> to each other, and thus, the conductive rubber portion <NUM> disposed inside the bead core <NUM> in the tire radial direction penetrates the carcass ply <NUM> in the tire radial direction and connects the conductive portion <NUM> and the chafer portion <NUM> to each other. Further, the conductive rubber portion <NUM> penetrates, in the tire radial direction, the portion of the carcass ply <NUM> between the ply cords 51b adjacent to each other in the tire circumferential direction to connect the conductive portion <NUM> and the chafer portion <NUM> to each other. As a result, the conductive rubber portion <NUM> of the present embodiment conducts electricity between the first surface and the second surface of the carcass ply <NUM>.

In the present specification, "the conductive rubber portion conducts electricity between the first surface and the second surface of the carcass ply" is not particularly limited as long as the conductive rubber portion conducts electricity from the first side of the carcass ply in the thickness direction to the second side of the carcass ply in the thickness direction, and may include a case where static electricity from the vehicle does not flow to the first surface and the second surface of the carcass ply. For example, in the present embodiment, static electricity from the vehicle does not flow to the carcass ply <NUM> itself, but flows from the chafer portion <NUM> located on the first side of the carcass ply <NUM> in the thickness direction to the conductive portion <NUM> located on the second side of the carcass ply <NUM> in the thickness direction via the conductive rubber portion <NUM>.

As shown in <FIG>, the second portion <NUM> is located outside the bead core <NUM> in the tire width direction. The second portion <NUM> extends outward in the tire radial direction from the outer end portion of the first portion <NUM> in the tire width direction. More specifically, the second portion <NUM> extends obliquely from the outer end portion of the first portion <NUM> in the tire width direction outward in the tire radial direction and inward in the tire width direction. An outer end portion of the second portion <NUM> in the tire radial direction is located outside the first chafer portion <NUM> in the tire radial direction. The conductive portion <NUM> is embedded in the second portion <NUM>. As a result, the second portion <NUM> is connected to the conductive portion <NUM>.

The whole of an outer portion 82a of the second portion <NUM> in the tire radial direction is located between a portion of the core covering portion <NUM> extending in the tire radial direction through the inside of the bead core <NUM> in the tire width direction and a portion of the core covering portion <NUM> extending in the tire radial direction through the outside of the bead core <NUM> in the tire width direction, in the tire width direction. More specifically, the outer portion 82a is provided so as to be laminated on the inner surface in the tire width direction of the portion of the carcass ply <NUM> that is folded outward in the tire radial direction around the bead core <NUM>.

An inner portion 82b of the second portion <NUM> in the tire radial direction has a base portion (intervening portion) 82c and a penetrating portion (embedded portion) 82d. In the present embodiment, the base portion 82c corresponds to the intervening portion located between the bead core <NUM> and the carcass ply <NUM>. The base portion 82c is a portion of the inner portion 82b located inside the carcass ply <NUM> in the tire width direction. In the present embodiment, the penetrating portion 82d corresponds to the embedded portion embedded in the carcass ply <NUM>. More specifically, the penetrating portion 82d corresponds to a second embedded portion embedded in a portion of the carcass ply <NUM> located outside the bead core <NUM> in the tire width direction. The penetrating portion 82d penetrates, in the tire width direction, a portion of the carcass rubber 51a located between the ply cords 51b.

As the base portion 82c and the penetrating portion 82d are provided, the inner portion 82b of the second portion <NUM> in the tire radial direction is disposed so as to penetrate the carcass layer <NUM> in the tire width direction. An inner end portion of the inner portion 82b in the tire width direction is in contact with the bead core <NUM>. An outer end portion of the inner portion 82b in the tire width direction is connected to the first chafer portion <NUM>. More specifically, the outer end portion of the inner portion 82b in the tire width direction is connected to the widthwise covering portion <NUM> of the first chafer portion <NUM>. Similar to the first portion <NUM> shown in <FIG>, the inner portion 82b penetrates, in the tire width direction, a portion between the ply cords 51b adjacent to each other in the tire circumferential direction to connect the conductive portion <NUM> and the chafer portion <NUM> to each other.

The dimension of the inner portion 82b in the tire width direction is larger than the dimension of the outer portion 82a in the tire width direction. The dimension in the tire width direction of the portion of the inner portion 82b located inside the carcass ply <NUM> in the tire width direction is smaller than the dimension in the tire width direction of the outer portion 82a. The dimension in the tire width direction of the portion of the inner portion 82b located inside the carcass ply <NUM> in the tire width direction, that is, the dimension in the tire width direction of the base portion 82c which is the intervening portion, becomes smaller toward the inside in the tire radial direction. A boundary portion between the outer portion 82a and the inner portion 82b in the tire radial direction is disposed at substantially the same position, in the tire radial direction, as the outer end portion of the bead core <NUM> in the tire radial direction.

The third portion <NUM> is located inside the bead core <NUM> in the tire width direction. The third portion <NUM> extends outward in the tire radial direction from the inner end portion of the first portion <NUM> in the tire width direction. An outer end portion of the third portion <NUM> in the tire radial direction is located outside the first chafer portion <NUM> in the tire radial direction. The conductive portion <NUM> is embedded in the third portion <NUM>. As a result, the third portion <NUM> is connected to the conductive portion <NUM>.

The whole of an outer portion 83a of the third portion <NUM> in the tire radial direction is located between a portion of the core covering portion <NUM> extending in the tire radial direction through the inside of the bead core <NUM> in the tire width direction and a portion of the core covering portion <NUM> extending in the tire radial direction through the outside of the bead core <NUM> in the tire width direction, in the tire width direction. More specifically, the outer portion 83a is provided so as to be laminated on the outer surface in the tire width direction of the portion of the carcass ply <NUM> extending from the tread portion <NUM> to the inside of the bead core <NUM> in the tire width direction.

An inner portion 83b of the third portion <NUM> in the tire radial direction has a base portion (intervening portion) 83c and a penetrating portion (embedded portion) 83d. In the present embodiment, the base portion 83c corresponds to the intervening portion located between the bead core <NUM> and the carcass ply <NUM>. The base portion 83c is a portion of the inner portion 83b located outside the carcass ply <NUM> in the tire width direction. In the present embodiment, the penetrating portion 83d corresponds to the embedded portion embedded in the carcass ply <NUM>. More specifically, the penetrating portion 83d corresponds to the second embedded portion embedded in a portion of the carcass ply <NUM> located inside the bead core <NUM> in the tire width direction. The penetrating portion 83d penetrates, in the tire width direction, a portion of the carcass rubber 51a located between the ply cords 51b.

As the base portion 83c and the penetrating portion 83d are provided, the inner portion 83b of the third portion <NUM> in the tire radial direction is disposed so as to penetrate the carcass layer <NUM> in the tire width direction. An outer end portion of the inner portion 83b in the tire width direction is in contact with the bead core <NUM>. An inner end portion of the inner portion 83b in the tire width direction is connected to the first chafer portion <NUM>. More specifically, the inner end portion of the inner portion 83b in the tire width direction is connected to the widthwise covering portion <NUM> of the first chafer portion <NUM>. Similar to the first portion <NUM> shown in <FIG>, the inner portion 83b penetrates, in the tire width direction, the portion between the ply cords 51b adjacent to each other in the tire circumferential direction to connect the conductive portion <NUM> and the chafer portion <NUM> to each other.

The dimension of the inner portion 83b in the tire width direction is larger than the dimension of the outer portion 83a in the tire width direction. The dimension in the tire width direction of the portion of the inner portion 83b located outside the carcass ply <NUM> in the tire width direction is smaller than the dimension in the tire width direction of the outer portion 83a. The dimension in the tire width direction of the portion of the inner portion 83b located outside the carcass ply <NUM> in the tire width direction, that is, the dimension in the tire width direction of the base portion 83c which is the intervening portion, becomes smaller toward the inside in the tire radial direction. A boundary portion between the outer portion 83a and the inner portion 83b in the tire radial direction is disposed at substantially the same position, in the tire radial direction, as the outer end portion of the bead core <NUM> in the tire radial direction.

As described above, on the outside of the bead core <NUM> in the tire width direction, the second portion <NUM> connects the conductive portion <NUM> and the first chafer portion <NUM> to each other, and thus, the conductive rubber portion <NUM> disposed outside the bead core <NUM> in the tire width direction penetrates the carcass ply <NUM> in the tire width direction and connects the conductive portion <NUM> and the chafer portion <NUM> to each other. Further, on the inside of the bead core <NUM> in the tire width direction, the third portion <NUM> connects the conductive portion <NUM> and the first chafer portion <NUM> to each other, and thus, the conductive rubber portion <NUM> disposed inside the bead core <NUM> in the tire width direction penetrates the carcass ply <NUM> in the tire width direction and connects the conductive portion <NUM> and the chafer portion <NUM> to each other. Further, the conductive rubber portion <NUM> penetrates, in the tire width direction, the portion of the carcass ply <NUM> between the ply cords 51b adjacent to each other in the tire circumferential direction to connect the conductive portion <NUM> and the chafer portion <NUM> to each other.

In the present embodiment, the dimension of the conductive rubber portion <NUM> in the tire width direction increases toward the inside in the tire radial direction. That is, the conductive rubber portion <NUM> has a larger dimension in the tire width direction in the inner portion in the tire radial direction.

As shown in <FIG>, a conductive path CP that releases static electricity from the vehicle is provided in the tire <NUM> so as to extend from a rim on which the tire <NUM> is mounted to the ground. The conductive path CP is a path in the tire <NUM> through which static electricity transmitted from the rim passes, and extends from the second chafer portion <NUM> to the tread surface portion 11a through the first chafer portion <NUM>, the conductive rubber portion <NUM>, the conductive portion <NUM>, the belt layer <NUM>, the gaps <NUM> of the belt reinforcing layer <NUM>, the tread under cushion <NUM>, and the antenna rubber <NUM> in this order. As a result, the static electricity of the vehicle transmitted from the rim can be released from the tread surface portion 11a to the ground.

As shown in <FIG>, in the present embodiment, the conductive path CP from the first chafer portion <NUM> to the conductive portion <NUM> via the conductive rubber portion <NUM> includes, for example, a path through which the static electricity flows from the radial covering portion <NUM> to the conductive portion <NUM> through the first portion <NUM>, and a path through which the static electricity flows from the widthwise covering portion <NUM> to the conductive portion <NUM> through the second portion <NUM>.

Further, as described above, the tread under cushion <NUM> and the belt layer <NUM> are connected to each other in the gaps <NUM> of the belt reinforcing layer <NUM>. Therefore, the static electricity that has flowed from the conductive portion <NUM> to the belt layer <NUM> flows from the gaps <NUM> to the tread under cushion <NUM>.

According to the present invention, the conductive rubber portion <NUM> conducts electricity between the first surface and the second surface of the carcass ply <NUM>. Therefore, even when the conductivity of the carcass ply <NUM> is low, the conductive rubber portion <NUM> allows static electricity from the vehicle to pass from the first side in the thickness direction to the second side in the thickness direction of the carcass ply <NUM>. Therefore, the amount of carbon contained in the carcass rubber 51a of the carcass ply <NUM> can be reduced to reduce the rolling resistance of the tire <NUM>, and the static electricity of the vehicle can be suitably released to the ground.

Further, according to the present invention, the conductive rubber portion <NUM> penetrates the first surface and the second surface of the carcass ply <NUM>. Specifically, in the present embodiment, the penetrating portions <NUM>, 82d, and 83d, which are the embedded portion of the conductive rubber portion <NUM>, penetrate the carcass ply <NUM> in the thickness direction. Therefore, the static electricity from the vehicle flows through the conductive rubber portion <NUM> (i.e., the penetrating portions <NUM>, 82d, and 83d), and thus, the static electricity from the vehicle can easily flow from the first side in the thickness direction to the second side in the thickness direction of the carcass ply <NUM>.

According to the present embodiment, the penetrating portions <NUM>, 82d, and 83d as the embedded portion of the conductive rubber portion <NUM> are embedded in the carcass ply <NUM>. That is, a portion of the conductive rubber portion <NUM> is embedded in the carcass ply <NUM>. Therefore, in the portion of the carcass ply <NUM> in which the conductive rubber portion <NUM> is embedded, electricity can easily pass through the conductive rubber portion <NUM>. As a result, even when the conductivity of the carcass ply <NUM> is low, static electricity from the vehicle can pass through the carcass ply <NUM> by the conductive rubber portion <NUM>. Therefore, it is possible to obtain the tire <NUM> having a structure that allows static electricity from the vehicle to be easily released to the ground, regardless of the conductivity of the carcass ply <NUM>. Accordingly, the amount of carbon contained in the carcass rubber 51a of the carcass ply <NUM> can be reduced to reduce the rolling resistance of the tire <NUM>, and the static electricity of the vehicle can be suitably released to the ground.

Further, according to the present embodiment, the penetrating portion <NUM>, which is the first embedded portion, is embedded in a portion of the carcass ply <NUM> located inside the bead core <NUM> in the tire radial direction. Therefore, the portion of the carcass ply <NUM> in which the conductive rubber portion <NUM> is embedded can be easily brought into contact with the chafer portion <NUM>. As a result, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion <NUM>, can easily pass through the carcass ply <NUM> by the conductive rubber portion <NUM> (i.e., the penetrating portion <NUM>). Therefore, the static electricity from the vehicle can be more suitably released to the ground. In the present embodiment, the penetrating portion <NUM>, which is the first embedded portion, is in contact with the radial covering portion <NUM>.

Further, according to the present embodiment, the penetrating portion 82d, which is the second embedded portion, is embedded in a portion of the carcass ply <NUM> located outside the bead core <NUM> in the tire width direction. Therefore, the portion of the carcass ply <NUM> in which the conductive rubber portion <NUM> is embedded can be easily brought into contact with the widthwise covering portion <NUM> of the first chafer portion <NUM>. As a result, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion <NUM>, can easily pass through the carcass ply <NUM> by the conductive rubber portion <NUM> (i.e., the penetrating portion 82d). Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the penetrating portion 83d, which is the second embedded portion, is embedded in a portion of the carcass ply <NUM> located inside the bead core <NUM> in the tire width direction. Therefore, the portion of the carcass ply <NUM> in which the conductive rubber portion <NUM> is embedded can be easily brought into contact with the widthwise covering portion <NUM> of the first chafer portion <NUM>. As a result, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion <NUM>, can easily pass through the carcass ply <NUM> by the conductive rubber portion <NUM> (i.e., the penetrating portion 83d). Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the penetrating portions <NUM>, 82d, and 83d, which are the embedded portion, are located between the ply cords 51b adjacent to each other in the tire circumferential direction. Therefore, it is easy to embed and dispose a portion of the conductive rubber portion <NUM> in the carcass ply <NUM>. Further, the penetrating portions <NUM>, 82d and 83d can easily penetrate the carcass ply <NUM> to be disposed, and the conductive portion <NUM> and the chafer portion <NUM> are more suitably connected to each other by the conductive rubber portion <NUM>.

Further, according to the present embodiment, at least a portion of the conductive rubber portion <NUM> is provided on an inner side in the tire radial direction than the outer end portion of the bead core <NUM> in the tire radial direction. Therefore, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion <NUM>, can easily pass through the carcass ply <NUM> by the conductive rubber portion <NUM>.

Further, according to the present embodiment, the conductive portion <NUM> extending along the carcass ply <NUM> and at least partially located between the carcass ply <NUM> and the bead core <NUM> is provided. Further, the conductive portion <NUM> is connected to the conductive rubber portion <NUM> via the base portions <NUM>, 82c, and 83c. Therefore, the static electricity transmitted to the conductive rubber portion <NUM> can be transmitted to the conductive portion <NUM>. As a result, even when the volume resistivity of the carcass rubber 51a in the carcass ply <NUM> is relatively large and the conductivity of the carcass ply <NUM> is low, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion <NUM>, can be transmitted to the conductive portion <NUM> via the conductive rubber portion <NUM>. Accordingly, the static electricity from the vehicle can be transferred to the tread portion <NUM> via the conductive portion <NUM>, and the static electricity can be released from the tread surface portion 11a of the tread portion <NUM> to the ground. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the volume resistivity of the conductive portion <NUM> is smaller than the volume resistivity of the conductive rubber portion <NUM>. Therefore, it is easy to suitably reduce the volume resistivity of the conductive portion <NUM>. As a result, the static electricity can suitably flow to the conductive portion <NUM> that forms a relatively long conductive path CP from the bead portion <NUM> to the tread portion <NUM>. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the conductive portion <NUM> is a thread member containing a metal. Therefore, it is easy to reduce the volume resistivity of the conductive portion <NUM> more suitably, and the conductive portion <NUM> makes it easier for the static electricity to flow from the bead portion <NUM> to the tread portion <NUM>. Accordingly, the static electricity from the vehicle can be more suitably released to the ground. Further, according to the present embodiment, the plurality of conductive portions <NUM> are disposed at intervals in the tire circumferential direction. Therefore, it is possible to increase the conductive path CP that allows static electricity to flow from the bead portion <NUM> to the tread portion <NUM>, and the conductive portion <NUM> makes it easier for the static electricity to flow from the bead portion <NUM> to the tread portion <NUM>. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the conductive rubber portion <NUM> connects the conductive portion <NUM> and the first chafer portion <NUM> to each other. The first chafer portion <NUM> covers a portion of the carcass ply <NUM> provided in the bead portion <NUM> from the inside in the tire radial direction and from both sides in the tire width direction. Therefore, the configuration is easily adopted, in which the conductive rubber portion <NUM> is disposed on the inside of the bead core <NUM> in the tire radial direction and on both sides of the bead core <NUM> in the tire width direction and penetrates the carcass ply <NUM> to connect the conductive portion <NUM> and the chafer portion <NUM> to each other. That is, as in the present embodiment, the radial covering portion <NUM> and the conductive portion <NUM> are easily connected by the first portion <NUM> of the conductive rubber portion <NUM>, and the widthwise covering portions <NUM> and <NUM> and the conductive portion <NUM> are easily connected by the second portion <NUM> and the third portion <NUM> of the conductive rubber portion <NUM>.

Further, according to the present embodiment, the conductive rubber portion <NUM> has the base portions <NUM>, 82c, and 83c as the intervening portions located between the bead core <NUM> and the carcass ply <NUM>. Therefore, the conductive rubber portion <NUM> is easily connected to the conductive portion <NUM> via the base portions <NUM>, 82c, and 83c. As a result, the static electricity can be suitably transmitted from the conductive rubber portion <NUM> to the conductive portion <NUM>. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the conductive rubber portion <NUM> has a larger dimension in the tire width direction in the inner portion in the tire radial direction. Therefore, a portion of the inner end portion of the conductive rubber portion <NUM> in the tire radial direction, which is connected to the chafer portion <NUM>, can be enlarged in the tire width direction. As a result, the conductive rubber portion <NUM> can be more suitably connected to the chafer portion <NUM>, and the static electricity can easily flow from the chafer portion <NUM> to the conductive portion <NUM> via the conductive rubber portion <NUM>. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the carcass rubber 51a is relatively difficult to conduct electricity. Therefore, it is difficult for the static electricity from the vehicle to pass through the carcass ply <NUM>. However, as described above, according to the present embodiment, the static electricity from the vehicle is easily released to the ground regardless of the conductivity of the carcass ply <NUM>. That is, the effect that the static electricity is easily released to the ground regardless of the conductivity of the carcass ply <NUM> described above can be obtained more usefully in a configuration in which the carcass rubber 51a is relatively difficult to conduct electricity.

Further, according to the present embodiment, the conductive rubber portion <NUM> is disposed outside the bead core <NUM> in the tire width direction and penetrates the carcass ply <NUM> in the tire width direction to connect the conductive portion <NUM> and the chafer portion <NUM> to each other. Therefore, in addition to the connection between the conductive portion <NUM> and the chafer portion <NUM> inside the bead core <NUM> in the tire radial direction, the conductive portion <NUM> and the chafer portion <NUM> can be connected to each other outside the bead core <NUM> in the tire width direction by the conductive rubber portion <NUM>. As a result, a connection area between the chafer portion <NUM> and the conductive portion <NUM> via the conductive rubber portion <NUM> can increase, and the static electricity from the chafer portion <NUM> can more suitably flow to the conductive portion <NUM> via the conductive rubber portion <NUM>. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

Further, according to the present embodiment, the conductive rubber portion <NUM> is disposed inside the bead core <NUM> in the tire width direction and penetrates the carcass ply <NUM> in the tire width direction to connect the conductive portion <NUM> and the chafer portion <NUM> to each other. Therefore, the conductive rubber portion <NUM> disposed on the inside of the bead core <NUM> in the tire radial direction and on both sides of the bead core <NUM> in the tire width direction penetrates the carcass ply <NUM> to connect the conductive portion <NUM> and the chafer portion <NUM> to each other. As a result, the connection area between the chafer portion <NUM> and the conductive portion <NUM> via the conductive rubber portion <NUM> can increase, and the static electricity from the chafer portion <NUM> can more suitably flow to the conductive portion <NUM> via the conductive rubber portion <NUM>. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

The scope of the present invention is not limited to the above embodiments, and the following configurations can also be adopted whilst falling within the scope of the appended claims.

The conductive rubber portion is not particularly limited as long as it has the embedded portion embedded in the carcass ply and has conductivity. The conductive rubber portion may not be connected to the conductive portion. The conductive rubber portion may not be connected to the chafer portion. As long as the embedded portion is embedded in the carcass ply, the position where the embedded portion is provided is not particularly limited. The embedded portion may not penetrate the carcass ply. The embedded portion may not be exposed on the surface of the carcass layer. The embedded portion may not be connected to the intervening portion. The intervening portion may not be provided.

The conductive rubber portion may not penetrate the carcass ply in the tire width direction. That is, for example, in the above-described embodiment, the conductive rubber portion <NUM> may not have the second portion <NUM> and the third portion <NUM>. The shape of the conductive rubber portion is not particularly limited. The conductive rubber portion may not have a large dimension in the tire width direction in the inner portion in the tire radial direction.

Further, the conductive rubber portion may be a portion of the carcass rubber in the carcass ply. In this case, the carcass rubber has a first rubber portion and a second rubber portion having volume resistivity smaller than that of the first rubber portion. The second rubber portion is a portion corresponding to the conductive rubber portion. The first rubber portion is a portion of the carcass rubber other than the second rubber portion. In this case as well, as described above, the static electricity from the vehicle can be easily released to the ground regardless of the conductivity of the carcass ply.

The conductive portion is not particularly limited as long as it extends along the carcass ply, and at least a portion thereof is located between the carcass ply and the bead core and has conductivity. The conductive portion may not contain metal. The conductive portion may be made of, for example, a conductive rubber. The conductive portion may not be a thread member, and may be a layered member laminated on the carcass ply. The volume resistivity of the conductive portion may be the same as the volume resistivity of the conductive rubber portion, or may be larger than the volume resistivity of the conductive rubber portion. The conductive portion may not be provided.

The chafer portion is not particularly limited as long as it has conductivity and covers at least a portion around the carcass ply. For example, in the above-described embodiment, the first chafer portion <NUM> may not have either or both of the widthwise covering portions <NUM> and <NUM>. When the first chafer portion <NUM> does not have the widthwise covering portion <NUM>, for example, the first chafer portion <NUM> is connected to the second chafer portion <NUM> at the outer end portion of the radial covering portion <NUM> in the tire width direction. The first chafer portion and the second chafer portion may be integrally molded. The chafer portion may not be provided.

The carcass layer may have two or more carcass plies. In this case, the conductive rubber portion penetrates the plurality of carcass plies in the tire radial direction to connect the chafer portion and the conductive portion to each other. The carcass layer may have an inner liner attached to the inner surface of the carcass ply.

The configuration of the tread portion is not particularly limited as long as static electricity can flow from the conductive portion, which extends to the tread portion, to the tread surface portion.

The tire of the above-described embodiment may be used in any vehicle.

The configurations described in the present specification can be appropriately combined within a range that does not contradict each other.

According to one aspect of the tire of the present invention, the conductive rubber portion conducts electricity between a first surface and a second surface of the carcass ply. Therefore, even when the conductivity of the carcass ply is low, the conductive rubber portion allows static electricity from a vehicle to pass from a first side in the thickness direction to a second side in the thickness direction of the carcass ply. Therefore, the amount of carbon contained in the carcass rubber of the carcass ply can be reduced to reduce the rolling resistance of the tire, and the static electricity of the vehicle can be suitably released to the ground.

The conductive rubber portion penetrates the first surface and the second surface of the at least one carcass ply.

According to this configuration, the static electricity from the vehicle flows through the conductive rubber portion, and thus, the static electricity from the vehicle can easily flow from the first side in the thickness direction to the second side in the thickness direction of the carcass ply.

The conductive rubber portion may include an embedded portion embedded in the carcass ply.

According to this configuration, a portion of the conductive rubber portion is embedded in the carcass ply. Therefore, in the portion of the carcass ply in which the conductive rubber portion is embedded, electricity can easily pass through the conductive rubber portion. As a result, even when the conductivity of the carcass ply is low, static electricity from the vehicle can pass through the carcass ply by the conductive rubber portion. Therefore, it is possible to obtain a tire having a structure that allows the static electricity from the vehicle to be easily released to the ground, regardless of the conductivity of the carcass ply. Accordingly, the amount of carbon contained in the carcass rubber of the carcass ply can be reduced to reduce the rolling resistance of the tire, and the static electricity of the vehicle can be suitably released to the ground.

The embedded portion may include a first embedded portion embedded in a portion of the carcass ply located inside the bead core in the tire radial direction.

According to this configuration, the portion of the carcass ply in which the conductive rubber portion is embedded, that is, the portion in which the first embedded portion is embedded can be easily brought into contact with the chafer portion. As a result, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion, can easily pass through the carcass ply by the first embedded portion. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

The embedded portion may include a second embedded portion embedded in a portion of the carcass ply located on one side of the bead core in the tire width direction.

According to this configuration, the portion of the carcass ply in which the conductive rubber portion is embedded, that is, the portion in which the second embedded portion is embedded can be easily brought into contact with the chafer portion. As a result, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion, can easily pass through the carcass ply by the second embedded portion. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

The embedded portion may penetrate the carcass ply in the thickness direction of the carcass ply.

According to this configuration, the static electricity from the vehicle flows through the conductive rubber portion (the embedded portion), and thus, the static electricity from the vehicle can easily flow from the first side in the thickness direction to the second side in the thickness direction of the carcass ply.

The carcass ply may include a carcass rubber and a plurality of ply cords embedded in the carcass rubber and disposed at intervals in the tire circumferential direction, and the embedded portion may be located between the ply cords.

According to this configuration, it is easy to embed and dispose a portion of the conductive rubber portion in the carcass ply. Further, the embedded portion can easily penetrate the carcass ply to be disposed, and the conductive portion and the chafer portion are more suitably connected to each other by the conductive rubber portion.

At least a portion of the conductive rubber portion may be provided on an inner side in the tire radial direction than an outer end portion of the bead core in the tire radial direction.

According to this configuration, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion, can easily pass through the carcass ply by the conductive rubber portion.

A conductive portion extending along the carcass ply and at least partially located between the carcass ply and the bead core may be provided, and the conductive portion may be connected to the conductive rubber portion.

According to this configuration, the static electricity transmitted to the conductive rubber portion can be transmitted to the conductive portion. As a result, even when the volume resistivity of the carcass rubber in the carcass ply is relatively large and the conductivity of the carcass ply is low, the static electricity from the vehicle, which has been transmitted from the rim to the chafer portion, can be transmitted to the conductive portion via the conductive rubber portion. As a result, the static electricity from the vehicle can be transferred to the tread portion via the conductive portion, and the static electricity can be released from the tread surface portion of the tread portion to the ground. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

The volume resistivity of the conductive portion may be smaller than the volume resistivity of the conductive rubber portion.

According to this configuration, it is easy to suitably reduce the volume resistivity of the conductive portion. As a result, the static electricity can suitably flow to the conductive portion that forms a relatively long conductive path CP from the bead portion to the tread portion. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

The conductive portion may be a thread member containing a metal.

According to this configuration, it is easy to reduce the volume resistivity of the conductive portion more suitably, and the conductive portion makes it easier for the static electricity to flow from the bead portion to the tread portion. Accordingly, the static electricity from the vehicle can be more suitably released to the ground.

A chafer portion having conductivity and covering at least a portion around the carcass ply may be provided, the chafer portion may include a first chafer portion that covers a portion of the carcass ply provided in the bead portion from an inside in the tire radial direction and from both sides in the tire width direction, and a second chafer portion that covers the portion of the carcass ply provided in the bead portion from an outside in the tire width direction and is connected to the first chafer portion, and the conductive rubber portion may connect the conductive portion and the first chafer portion to each other.

According to this configuration, a configuration is easily adopted, in which the conductive rubber portion is disposed on the inside of the bead core in the tire radial direction and on both sides of the bead core in the tire width direction and penetrates the carcass ply to connect the conductive portion and the chafer portion to each other.

The conductive rubber portion may have a configuration in which the dimension in the tire width direction is large in an inner portion in the tire radial direction.

According to this configuration, a portion of the inner end portion of the conductive rubber portion in the tire radial direction, which is connected to the chafer portion, can be enlarged in the tire width direction. As a result, the conductive rubber portion can be more suitably connected to the chafer portion, and the static electricity can easily flow from the chafer portion to the conductive portion via the conductive rubber portion. Therefore, the static electricity from the vehicle can be more suitably released to the ground.

According to another aspect of the present disclosure, not falling within the scope of the appended claims but included to aid understanding of the invention, a tire includes a bead core provided in the bead portion, and a carcass ply covering at least a portion around the bead core, in which the carcass ply includes a carcass rubber, and the carcass rubber includes a first rubber portion, and a second rubber portion having volume resistivity smaller than that of the first rubber portion.

According to another aspect of the tire of the present disclosure, similar to the above description, it is possible to obtain a tire having a structure that allows static electricity from a vehicle to be easily released to the ground, regardless of the conductivity of the carcass ply. Accordingly, the amount of carbon contained in the carcass rubber of the carcass ply can be reduced to reduce the rolling resistance of the tire, and the static electricity of the vehicle can be suitably released to the ground.

Claim 1:
A tire (<NUM>) including a tread portion (<NUM>), a sidewall portion (<NUM>), and a bead portion (<NUM>), the tire comprising:
a bead core (<NUM>) provided in the bead portion;
at least one carcass ply (<NUM>) provided along at least a portion of the bead core around a core axis of the bead core; and
a conductive rubber portion (<NUM>) provided between the carcass ply and the bead core,
wherein the conductive rubber portion conducts electricity between a first surface and a second surface of the at least one carcass ply;
characterised in that the conductive rubber portion penetrates the first surface and the second surface of the at least one carcass ply.