Patent Description:
<CIT> discloses a vehicle wheel that includes a solid tire base body and a rim on which the tire base body is mounted. The tire base body has a base rubber layer disposed on a rim side. The base rubber layer has a protrusion that engages with a recess of the rim. The base rubber layer is formed of a rubber composition containing vinylon fibers. Further prior art solid tires are disclosed in the following documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. In particular, <CIT> discloses a solid tire to be mounted on a side ringless type rim, and includes a base rubber layer for being assembled on the rim, and the base rubber layer is on one side in the tire axial direction. The first side is provided with a protrusion for projecting from the bottom surface of the tire and being fitted into the recessed portion of the rim, and the protrusion is an outer rubber portion arranged on the outer surface side of the protrusion and the outer side. It includes an inner rubber portion arranged inside the rubber portion and having different rubber physical properties from the outer rubber portion. Further, <CIT> discloses a solid rubber tire, at least consisting of a base profile which has a plurality of tensile strength members arranged in the circumferential direction of the tire, of a damper layer which is arranged radially above the base profile and of a tread part which forms the outer circumference of the tire, characterized in that hollow bodies, preferably hollow spheres, are arranged in the damper layer, which are completely enclosed by the rubber material of the damper layer and firmly connected to it.

A mold for vulcanizing and molding the tire base body has a recess for forming the protrusion. The rubber composition which has been subjected to heat and pressure and plasticized is filled in the recess when vulcanized and molded. Thus, the protrusion is vulcanized and molded.

However, fluidity of the rubber composition containing the vinylon fibers as described above tends to be lowered in vulcanization molding, and the rubber composition does not sufficiently flow into the recess, so that molding defect of the protrusion is likely to occur.

The present invention has been made in view of the aforementioned circumstances, and a main object of the present invention is to provide a solid tire capable of maintaining tire stiffness while molding defect of a protrusion disposed in a base rubber layer is prevented.

The present invention is directed to a solid tire. The solid tire includes: a base rubber layer configured to be mounted on a sideringless rim being structured to include a rim seat and a flange portion, wherein the rim seat is structured to include a recess and a seat portion; and a tread rubber layer disposed outward of the base rubber layer in a tire radial direction. A protrusion is disposed on an inner circumferential surface, in the tire radial direction, of the base rubber layer so as to protrude inwardly in the tire radial direction on one side in a tire axial direction. The base rubber layer includes a base inner circumferential layer forming the inner circumferential surface side portion including the protrusion and a contact portion, and a base outer circumferential layer disposed outward of the base inner circumferential layer in the tire radial direction. The base inner circumferential layer is formed of a first rubber material in which no fibers are blended. The base outer circumferential layer is formed of a second rubber material in which one or more fibers are blended. The fiber has a diameter and a length, wherein the fiber diameter is not greater than <NUM>, and the fiber length is not greater than <NUM>. The inner circumferential surface, in the tire radial direction, of the solid tire is disposed on the rim seat when the solid tire is mounted on the rim, and wherein the contact portion is disposed on the other side in the tire axial direction relative to the protrusion and further comes into contact with the outer surface, in the tire radial direction, of the seat portion when mounted on the rim.

The solid tire of the present invention has the above-described structure, and can thus maintain tire stiffness while molding defect of the protrusion disposed in the base rubber layer is prevented.

It is to be understood that the drawings include exaggerated expressions and the dimensional ratio in the drawings is expressed so as to be different from that of the actual structure in order to aid in understanding of the present invention. The same or common components are denoted by the same reference characters throughout embodiments, and repeated description is omitted. Furthermore, the embodiments and specific structures in the drawings are for aiding in understanding of the present invention, and the present invention is not limited to the illustrated specific structure.

<FIG> is a cross-sectional view of a solid tire <NUM> of the present embodiment. The solid tire <NUM> of the present embodiment is mounted on a sideringless rim <NUM>. Thus, a wheel <NUM> is structured to include the solid tire <NUM> and the sideringless rim <NUM>. The solid tire <NUM> (wheel <NUM>) having such a structure is preferably used for, for example, industrial vehicles such as forklifts.

The sideringless rim (hereinafter, may be simply referred to as "rim") <NUM> of the present embodiment is structured to include a rim seat <NUM> and a flange portion <NUM> as in a conventional rim.

In the present embodiment, an inner circumferential surface <NUM>, in the tire radial direction, of the solid tire <NUM> is disposed on the rim seat <NUM> when the solid tire <NUM> is mounted on the rim <NUM>. In the present embodiment, the rim seat <NUM> is structured to include a recess <NUM> and a seat portion <NUM>.

In the present embodiment, the recess <NUM> is recessed inwardly in the tire radial direction on one side S1, in the tire axial direction, of the rim seat <NUM> (rim <NUM>). The recess <NUM> having such a structure can prevent removal of the solid tire <NUM> (fix the solid tire <NUM>) since a protrusion <NUM> of the solid tire <NUM> fits into the recess <NUM> when the solid tire <NUM> is mounted on the rim <NUM>.

In the present embodiment, the seat portion <NUM> is disposed on the other side S2 in the tire axial direction relative to the recess <NUM>. In the present embodiment, the seat portion <NUM> is structured to include a first seat portion 8A, and a second seat portion 8B disposed on the other side S2 in the tire axial direction relative to the first seat portion 8A. The seat portion <NUM> may be formed of one of the first seat portion 8A or the second seat portion 8B, or may additionally include another seat portion.

In the present embodiment, the first seat portion 8A is recessed inwardly in the tire radial direction (has the outer diameter set to be smaller) as compared with the second seat portion 8B. The first seat portion 8A and the second seat portion 8B are connected to each other via a stepped portion 8C.

In the present embodiment, the flange portion <NUM> is disposed on the other side S2 in the tire axial direction relative to the rim seat <NUM> (second seat portion 8B), and protrudes outwardly from the rim seat <NUM> in the tire radial direction. The flange portion <NUM> having such a structure supports the side surface of the solid tire <NUM> on the other side S2 in the tire axial direction when the solid tire <NUM> is mounted on the rim <NUM>.

The solid tire <NUM> of the present embodiment is structured to include a base rubber layer <NUM> and a tread rubber layer <NUM>.

The base rubber layer <NUM> is mounted on the rim <NUM>. In the present embodiment, the inner circumferential surface <NUM>, in the tire radial direction, of the base rubber layer <NUM> is disposed on the rim seat <NUM> when mounted on the rim <NUM>. In the present embodiment, the inner circumferential surface <NUM> has the protrusion <NUM> and a contact portion <NUM>.

In the present embodiment, the protrusion <NUM> protrudes inwardly in the tire radial direction on the one side S1 in the tire axial direction. The protrusion <NUM> fits into the recess <NUM> when mounted on the rim <NUM>. Thus, the solid tire <NUM> (base rubber layer <NUM>) is fixed to (prevented from being removed from) the rim <NUM>. In order to stably mount the solid tire <NUM> on the rim <NUM>, the maximum height H4, in the tire radial direction, of the protrusion <NUM> is set to be, for example, <NUM>% to <NUM>% of the maximum tire cross-sectional height H2 in the tire radial direction. In the description herein, dimensions and the like of the components of the solid tire <NUM> represent values measured in a state where the solid tire <NUM> has not been mounted on the rim <NUM> yet.

In the present embodiment, the contact portion <NUM> is disposed on the other side S2 in the tire axial direction relative to the protrusion <NUM>. In the present embodiment, the contact portion <NUM> comes into contact with the outer surface, in the tire radial direction, of the seat portion <NUM> when mounted on the rim <NUM>.

In the present embodiment, the contact portion <NUM> is structured to include a first contact portion 15A, and a second contact portion 15B disposed on the other side S2 in the tire axial direction relative to the first contact portion 15A. The contact portion <NUM> may be composed of one of the first contact portion 15A or the second contact portion 15B, or may additionally include another contact portion.

In the present embodiment, the second contact portion 15B is recessed outwardly in the tire radial direction (has the inner diameter set to be greater) as compared with the first contact portion 15A. The first contact portion 15A and the second contact portion 15B are connected to each other via a stepped portion 15C. In the present embodiment, the first contact portion 15A comes into contact with the first seat portion 8A of the rim <NUM>. The second contact portion 15B comes into contact with the second seat portion 8B of the rim <NUM>.

In the present embodiment, the base rubber layer <NUM> has a plurality of (four in the present embodiment) tensile bodies <NUM> embedded therein. Each of the tensile bodies <NUM> is preferably formed in an annular shape that extends continuously in the tire circumferential direction. The tensile bodies <NUM> having such a structure exhibit a binding effect and can thus enhance stability of the solid tire <NUM> mounted on the rim <NUM>.

In the present embodiment, the base rubber layer <NUM> is structured to include a base inner circumferential layer 11A that forms the inner circumferential surface <NUM> side portion including the protrusion <NUM>, and a base outer circumferential layer 11B disposed outward of the base inner circumferential layer 11A in the tire radial direction. The base inner circumferential layer 11A and the base outer circumferential layer 11B will be described below in detail.

The tread rubber layer <NUM> has a tread surface <NUM> for coming into contact with a road surface. In the present embodiment, the profile of the tread surface <NUM> has a symmetrical shape having the tire equator C at the center thereof, and is formed in an arc-like shape projecting outwardly in the tire radial direction.

In the present embodiment, firstly, the solid tire <NUM> is inserted in the rim <NUM> from the one side S1 (recess <NUM> side) toward the other side S2 in the tire axial direction, and the protrusion <NUM> of the solid tire <NUM> fits into the recess <NUM> of the rim <NUM>. Thus, the solid tire <NUM> is mounted on the rim <NUM>. In the present embodiment, as described above, a side ring (not shown) need not be used for the solid tire <NUM>, so that the solid tie <NUM> is easily mounted on the rim <NUM>.

In the present embodiment, in the solid tire <NUM>, the second contact portion 15B is recessed outwardly in the tire radial direction (has the inner diameter set to be greater) as compared with the first contact portion 15A. Meanwhile, in the rim <NUM> of the present embodiment, the first seat portion 8A is recessed inwardly in the tire radial direction (has the outer diameter set to be smaller) as compared with the second seat portion 8B. Thus, in the present embodiment, when the solid tire <NUM> is inserted in the rim <NUM> from the one side S1 (recess <NUM> side) toward the other side S2 in the tire axial direction, contact pressure between the second contact portion 15B and the first seat portion 8A can be lowered. Therefore, in the present embodiment, the solid tire <NUM> can be easily mounted on the rim <NUM>.

In the present embodiment, the solid tire <NUM> is produced by vulcanizing and molding an unvulcanized green tire <NUM> as in conventional art. Unvulcanized means all the states before a completely vulcanized state, and a so-called semi-vulcanized state is included in the "unvulcanized" state. A vulcanization mold is used for the vulcanization molding. <FIG> is a cross-sectional view of the green tire <NUM> and a vulcanization mold <NUM> according to the present embodiment.

The vulcanization mold <NUM> is structured to include a pair of first molds 21A, 21A and a pair of second molds 21B, 21B. The first molds 21A, 21A and the second molds 21B, 21B are configured to be openable and closable.

In the present embodiment, the pair of first molds 21A, 21A form a first molding surface <NUM> for molding a tread surface <NUM>, sidewall side surfaces <NUM>, and a part of bead side surfaces <NUM> in the solid tire <NUM>. In the present embodiment, the pair of second molds 21B, 21B form a second molding surface <NUM> for molding a part of the bead side surfaces <NUM> and the inner circumferential surface <NUM> in the solid tire <NUM>. Among the pair of second molds 21B, 21B, the second mold 21B disposed on the one side S1 in the tire axial direction has a recess <NUM> for molding the protrusion <NUM> of the solid tire <NUM>.

In the vulcanization mold <NUM>, the pair of first molds 21A, 21A and the pair of second molds 21B, 21B are closed to form a cavity <NUM> defined by the molding surface (first molding surface <NUM> and second molding surface <NUM>) formed over the molds 21A, 21B.

In the vulcanizing and molding process step, the green tire <NUM> is put in the vulcanization mold <NUM> in which the pair of first molds 21A, 21A and the pair of second molds 21B, 21B are opened. Subsequently, the pair of first molds 21A, 21A and the pair of second molds 21B, 21B are closed. A rubber material of the green tire <NUM> is subjected to heat and pressure and plasticized, and the green tire <NUM> is vulcanized and molded in the cavity <NUM>. The plasticized rubber material of the green tire <NUM> is filled in the recess <NUM> of the second mold 21B. Thus, the solid tire <NUM> (shown in <FIG>) having the protrusion <NUM> is produced.

If fluidity of the rubber material of the base rubber layer <NUM> is lowered in the vulcanization molding, the plasticized rubber material does not sufficiently flow into the recess <NUM>, so that molding defect of the protrusion <NUM> is likely to occur. Meanwhile, in a case where a rubber material having high fluidity is merely used, stiffness required for the solid tire <NUM> is unlikely to be assured.

In the present embodiment, the base inner circumferential layer 11A and the base outer circumferential layer 11B are formed of a first rubber material <NUM> and a second rubber material <NUM> described below, whereby tire stiffness is maintained while molding defect of the protrusion <NUM> is prevented.

The base inner circumferential layer 11A is formed of the first rubber material <NUM> in which no fibers are blended. In the present embodiment, the fiber is for reinforcing the rubber material. Although such a fiber can reinforce the rubber material, the fiber tends to lower fluidity of the rubber material in the vulcanization-molding shown in <FIG>. The fiber will be described below in detail.

In the present embodiment, the base rubber layer <NUM> that forms the inner circumferential surface <NUM> side portion including the protrusion <NUM> is formed of the first rubber material <NUM> in which no fibers are blended. Therefore, in the vulcanization-molding shown in <FIG>, fluidity of the plasticized first rubber material <NUM> can be enhanced. Therefore, in the present embodiment, the first rubber material <NUM> can be sufficiently spread in the cavity <NUM> of the vulcanization mold <NUM>, so that molding defect of the protrusion <NUM> can be prevented. Furthermore, in the present embodiment, the enhancement of fluidity of the first rubber material <NUM> can prevent molding defect of the first contact portion 15A and the second contact portion 15B connected to each other via the stepped portion 15C.

The base outer circumferential layer 11B is formed of the second rubber material <NUM> in which one or more fibers are blended.

Any fiber capable of reinforcing the rubber material is adopted as appropriate. In the present embodiment, as the fiber, for example, organic fibers (the examples of which include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers) are adopted. Among these fibers, one of the fibers may be blended in the second rubber material <NUM> or a plurality of kinds of the fibers may be blended in the second rubber material <NUM>. The blended components of the second rubber material <NUM> may be the same as the blended components of the first rubber material <NUM> except for the blended fibers, or the blended components may be different between the second rubber material <NUM> and the first rubber material <NUM>. The components to be blended in the first rubber material <NUM> and the second rubber material <NUM> are determined as appropriate based on blended components in a rubber material used for a conventional base rubber layer.

A fiber length and a fiber diameter can be determined as appropriate. In the present embodiment, the fiber length is not greater than <NUM> and more preferably not greater than <NUM> in consideration of fluidity of the second rubber material <NUM> in the vulcanization molding. Similarly, the fiber diameter is not greater than <NUM> and more preferably not greater than <NUM>.

In the solid tire <NUM> of the present embodiment, the base outer circumferential layer 11B disposed outward of the base inner circumferential layer 11A in the tire radial direction is formed of the second rubber material <NUM> in which the fibers are blended, and thus has high stiffness by a rubber reinforcing effect exhibited by the fibers. Since the base outer circumferential layer 11B does not have a member such as the protrusion <NUM> having a complicated shape, even when the base outer circumferential layer 11B is formed of the second rubber material <NUM> having lower fluidity as compared with the first rubber material <NUM>, molding defect does not occur in the vulcanization-molding shown in <FIG>.

Thus, in the solid tire <NUM> of the present embodiment, the base rubber layer <NUM> includes the base inner circumferential layer 11A formed of the first rubber material <NUM> and the base outer circumferential layer 11B formed of the second rubber material <NUM>, and can thus maintain tire stiffness while preventing molding defect of the protrusion <NUM>.

In order to effectively exhibit the above-described effect, a rubber hardness of the first rubber material <NUM> is preferably set to be <NUM> to <NUM> degrees. In a case where the rubber hardness is set to be not less than <NUM> degrees, stiffness of the base inner circumferential layer 11A including the protrusion <NUM> can be maintained and fixability to the rim (prevention of removal from the rim) can be enhanced after the vulcanization molding while fluidity of the first rubber material <NUM> is enhanced. Meanwhile, in a case where the rubber hardness is set to be not greater than <NUM> degrees, stiffness of the protrusion <NUM> can be prevented from becoming higher than required, so that, for example, damage (breakage) to the protrusion <NUM> can be prevented when the protrusion <NUM> is mounted on the rim <NUM>. From these viewpoints, the rubber hardness is more preferably not less than <NUM> degrees and preferably not greater than <NUM> degrees.

In the description herein, the "rubber hardness" represents type A durometer hardness that is measured at a standard temperature of <NUM>±<NUM> by a type A durometer in accordance with JIS-K6253.

As shown in <FIG>, the maximum height H1, in the tire radial direction, of the base inner circumferential layer 11A is preferably set to be <NUM>% to <NUM>% of the maximum tire cross-sectional height H2 in the tire radial direction. In a case where the maximum height H1 is set to be not less than <NUM>% of the maximum tire cross-sectional height H2, an interface <NUM> between the base inner circumferential layer 11A and the base outer circumferential layer 11B can be prevented from being formed at the protrusion <NUM>. Thus, when, for example, the solid tire <NUM> is mounted on the rim <NUM>, damage (for example, separation of the protrusion <NUM>) at the interface <NUM> can be prevented. Meanwhile, in a case where the maximum height H1 is set to be not greater than <NUM>% of the maximum tire cross-sectional height H2, reduction of a proportion of the base outer circumferential layer 11B can be prevented, so that tire stiffness can be maintained. From these viewpoints, the maximum height H1 is preferably not less than <NUM>% of the maximum tire cross-sectional height H2 and preferably not greater than <NUM>% thereof.

The specific gravity of the second rubber material <NUM> is preferably set to be <NUM> to <NUM>. In a case where the specific gravity is set to be not less than <NUM>, the base outer circumferential layer 11B can have a high stiffness by the reinforcing effect exhibited by the fibers, and steering stability can be enhanced. Meanwhile, in a case where the specific gravity is set to be not greater than <NUM>, reduction of extensibility of the second rubber material <NUM> (base outer circumferential layer 11B) can be prevented, and durability of the solid tire <NUM> can be maintained. From these viewpoints, the specific gravity is preferably not less than <NUM> and preferably not greater than <NUM>. In the present embodiment, the second rubber material <NUM> in which no fibers are blended has a specific gravity of not greater than <NUM>.

The maximum height H3, in the tire radial direction, of the base outer circumferential layer 11B is preferably set to be <NUM>% to <NUM>% of the maximum tire cross-sectional height H2 in the tire radial direction. In a case where the maximum height H3 is set to be not less than <NUM>% of the maximum tire cross-sectional height H2, since the proportion of the base outer circumferential layer 11B having high stiffness can be increased, tire stiffness can be maintained, so that steering stability can be enhanced. Meanwhile, in a case where the maximum height H3 is set to be not greater than <NUM>% of the maximum tire cross-sectional height H2, reduction of a proportion (height in the tire radial direction) of the tread rubber layer <NUM> can be inhibited, and shortening of tire wear life and reduction of durability can be prevented. From these viewpoints, the maximum height H3 is preferably not less than <NUM>% of the maximum tire cross-sectional height H2 and preferably not greater than <NUM>% thereof.

Although the particularly preferred embodiment of the present invention has been described above in detail, the present invention is not limited to the illustrated embodiment.

A solid tire shown in <FIG> was produced as a test tire based on specifications described below (Example <NUM>). In Example <NUM>, the base rubber layer was structured to include a base inner circumferential layer formed of a first rubber material in which no fibers were blended, and a base outer circumferential layer formed of a second rubber material in which fibers were blended. For comparison, a solid tire including a base rubber layer that was merely formed of a rubber material in which fiber materials were blended as in the tire base body disclosed in <CIT> was produced as a test tire (Comparative example). For each test tire, presence or absence of molding defect of the protrusion, and tire stiffness (steering stability and durability) were evaluated. Common specifications and test methods were as follows. Table <NUM> indicates the test results.

Base rubber layer:
Maximum height (H1+H3)/H2: <NUM>%.

<NUM> test tires were produced for each of Example <NUM> and Comparative example. After vulcanization molding, presence or absence of molding defect of the protrusion was visually checked.

Each test tire was mounted on the above-described rim, and the test tires were mounted to all wheels of a vehicle (<NUM>-ton counterweight-type forklift), and cargo-handling for a load of around <NUM> tons was performed. A driver made sensory evaluation for steering stability during the cargo-handling. The evaluation is indicated as an index with the index of Example <NUM> being <NUM>. The greater the value is, the more excellent steering stability is. When the evaluation indicated a value of not less than <NUM>, steering stability was obtained as desired and tire stiffness was maintained.

After the above-described cargo-handling was performed for <NUM> hours, a state of occurrence of damage to the solid tire was visually checked. The evaluation is indicated as an index with the index of Example <NUM> being <NUM>. The greater the value is, the less occurrence of the damage is and the more excellent durability is. When the evaluation indicated a value of not less than <NUM>, durability was obtained as desired and tire stiffness was maintained.

According to the test results, it was confirmed that tire stiffness was maintained while molding defect of the protrusion was prevented in the solid tire of Example <NUM> as compared with the solid tire of Comparative example.

Solid tires were produced as sample tires based on specifications in Table <NUM> such that the rubber hardness of the first rubber material and the maximum height H1 of the base inner circumferential layer were different among the examples (Examples <NUM> to <NUM>). For each test tire, presence or absence of molding defect of the protrusion and tire stiffness (steering stability and durability) were evaluated. Furthermore, for each test tire, fixability to the rim and resistance to damage to the protrusion at the time of mounting the test tire on the rim were evaluated. The specifications were common to those for Example <NUM> (described in Example A) except for the specifications indicated in Table <NUM>. Presence or absence of molding defect of the protrusion and tire stiffness (steering stability and durability) were tested as described in Example A.

Stress required for removing each test tire from the rim after the test tire was mounted on the rim, was measured. The evaluation is indicated as an index with the index of Example <NUM> being <NUM>. The greater the value is, the more excellent fixability to the rim is. When the evaluation indicated a value of not less than <NUM>, fixability to the rim was obtained as desired and tire stiffness was maintained.

<NUM> test tires were produced for each example. After vulcanization molding, a state of occurrence of damage to the protrusion was visually checked after the test tire was mounted on the rim. The evaluation is indicated as an index with the index of Example <NUM> being <NUM>. The greater the value is, the less occurrence of the damage is and the more excellent durability is. When the evaluation indicated a value of not less than <NUM>, durability was obtained as desired.

According to the test results, it was confirmed that, in the solid tires of Examples <NUM> to <NUM>, tire stiffness (steering stability and durability) was maintained while molding defect of the protrusion was prevented. Furthermore, damage to the protrusion at the time of mounting the test tire on the rim was reduced while steering stability, durability, and fixability to the rim were enhanced in Example <NUM>, Example <NUM>, Example <NUM>, Example <NUM>, and Example <NUM> in which rubber hardness of the first rubber material and the maximum height H1 of the base inner circumferential layer were in preferable ranges as compared with the other examples.

Solid tires were produced as sample tires based on specifications in Table <NUM> such that the specific gravity of the second rubber material and the maximum height H3 of the base outer circumferential layer were different among the examples (Example <NUM>, and Examples <NUM> to <NUM>). For each test tire, presence or absence of molding defect of the protrusion, tire stiffness (steering stability and durability), fixability to the rim, and resistance to damage to the protrusion at the time of mounting the test tire on the rim, were evaluated. The specifications were common to those for Example <NUM> (described in Example A) except for the specifications indicated in Table <NUM>. The test methods were as described in Example A and Example B.

Claim 1:
A solid tire (<NUM>) comprising:
a base rubber layer (<NUM>) configured to be mounted on a sideringless rim (<NUM>) being structured to include a rim seat (<NUM>) and a flange portion (<NUM>), wherein the rim seat (<NUM>) is structured to include a recess (<NUM>) and a seat portion (<NUM>); and
a tread rubber layer (<NUM>) disposed outward of the base rubber layer (<NUM>) in a tire radial direction, wherein
a protrusion (<NUM>) is disposed on an inner circumferential surface (<NUM>), in the tire radial direction, of the base rubber layer (<NUM>) so as to protrude inwardly in the tire radial direction on one side (S1) in a tire axial direction,
the base rubber layer (<NUM>) includes a base inner circumferential layer (11A) forming the inner circumferential surface (<NUM>) side portion including the protrusion (<NUM>) and a contact portion (<NUM>), and a base outer circumferential layer (11B) disposed outward of the base inner circumferential layer (11A) in the tire radial direction,
the base inner circumferential layer (11A) is formed of a first rubber material (<NUM>) in which no fibers are blended,
the base outer circumferential layer (11B) is formed of a second rubber material (<NUM>) in which one or more fibers are blended,
wherein the fiber has a diameter and a length, wherein the fiber length is not greater than <NUM>,
wherein the inner circumferential surface (<NUM>), in the tire radial direction, of the solid tire (<NUM>) is disposed on the rim seat (<NUM>) when the solid tire is mounted on the rim (<NUM>), characterized in that
the fiber diameter is not greater than <NUM> and
wherein the contact portion (<NUM>) is disposed on the other side (S2) in the tire axial direction relative to the protrusion (<NUM>) and further comes into contact with the outer surface, in the tire radial direction, of the seat portion (<NUM>) when mounted on the rim (<NUM>).