solid tires

Abstract

To provide a solid tire that can maintain rigidity of the tire, while preventing a protrusion part arranged on a base rubber layer from being poorly formed.SOLUTION: A solid tire 1 comprises a base rubber layer 11 attached to a side ringless rim 2, and a tread rubber layer 12 arranged outside in a tire radial direction of the base rubber layer 11. An inner peripheral surface 13 in the tire radial direction of the base rubber layer 11 is provided with a protrusion part 14 protruding to inside in the tire radial direction at one side in a tire axial direction. The base rubber layer 11 includes a base inner peripheral layer 11A including the protrusion part 14, which forms the inner peripheral surface side and a base outer peripheral layer 11B arranged outside in the tire radial direction of the base inner peripheral layer 11A. The base inner peripheral layer 11A is constituted of a first rubber material 31 which is not blended with a fiber. The base outer peripheral layer 11B is constituted of a second rubber material 32 which is blended with a fiber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to solid tires. [Background technology]

[0002] Patent Document 1 listed below describes a vehicle wheel including a solid tire base and a rim on which the tire base is mounted. The tire base is provided with a base rubber layer disposed on the rim side. This base rubber layer is provided with protrusions that engage with recesses in the rim. The base rubber layer is formed from a rubber composition containing vinylon fiber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-320807 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a mold for vulcanization molding of a tire base body is provided with recesses for molding the protrusions. During vulcanization molding, the recesses are filled with the rubber composition plasticized by heat and pressure, thereby forming the protrusions through vulcanization.

[0005] However, rubber compositions containing the above vinylon fibers tend to have low fluidity during vulcanization molding, and do not flow sufficiently into recesses, which can lead to poor molding of protrusions.

[0006] The present disclosure has been devised in consideration of the above-described circumstances, and its main objective is to provide a solid tire that can maintain the rigidity of the tire while preventing molding defects of protrusions provided on the base rubber layer. [Means for solving the problem]

[0007] The present disclosure relates to a solid tire comprising a base rubber layer attached to a side ring-less rim and a tread rubber layer arranged radially outward of the base rubber layer, wherein the radially inner surface of the base rubber layer is provided with a protrusion that protrudes radially inward on one side in the tire axial direction, the base rubber layer including the protrusion and forming the inner surface side, and a base outer layer arranged radially outward of the base inner layer, wherein the base inner layer is made of a first rubber material that does not contain fibers, and the base outer layer is made of a second rubber material that contains fibers. [Effects of the Invention]

[0008] By employing the above-described configuration, the solid tire of the present disclosure can maintain the rigidity of the tire while preventing molding defects of the protrusions provided on the base rubber layer. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a solid tire according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a raw tire and a vulcanization mold according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be understood that the drawings include exaggerated representations and representations that differ from the dimensional ratios of actual structures in order to facilitate understanding of the contents of the disclosure. Furthermore, identical or common elements are designated by the same reference numerals throughout the embodiments, and redundant explanations will be omitted. Furthermore, the specific configurations shown in the embodiments and drawings are intended to facilitate understanding of the contents of the present disclosure, and the present disclosure is not limited to the specific configurations shown in the drawings.

[0011] [wheel] Fig. 1 is a cross-sectional view showing a solid tire 1 of this embodiment. The solid tire 1 of this embodiment is mounted on a side ring-less rim 2. This forms a wheel 3 including the solid tire 1 and the side ring-less rim 2. Such a solid tire 1 (wheel 3) is suitable for use on industrial vehicles such as forklifts.

[0012] [Side ring-less rim] The side ring-less rim (hereinafter sometimes simply referred to as "rim") 2 of this embodiment is configured to include a rim seat 5 and a flange portion 6, similar to a conventional rim.

[0013] When the solid tire 1 is mounted, the rim seat 5 of this embodiment is disposed on the inner peripheral surface 13 in the tire radial direction of the solid tire 1. The rim seat 5 of this embodiment is configured to include a recessed portion 7 and a seat portion 8.

[0014] The recessed portion 7 of this embodiment is recessed radially inward on one side S1 in the tire axial direction of the rim seat 5 (rim 2). When the solid tire 1 is mounted, the protrusions 14 of the solid tire 1 are fitted into such recessed portion 7, thereby preventing (securing) the solid tire 1 from slipping out.

[0015] The seat portion 8 of this embodiment is disposed on the other side S2 in the tire axial direction with respect to the recessed portion 7. The seat portion 8 of this embodiment is configured to include a first seat portion 8A and a second seat portion 8B disposed on the other side S2 in the tire axial direction with respect to the first seat portion 8A. Note that the seat portion 8 may be configured with one of the first seat portion 8A and the second seat portion 8B, or may further include another seat portion.

[0016] In this embodiment, the first seat portion 8A is recessed radially inward relative to the second seat portion 8B (having a smaller outer diameter). The first seat portion 8A and the second seat portion 8B are connected via a step portion 8C.

[0017] The flange portion 6 of this embodiment is disposed on the other side S2 in the tire axial direction with respect to the rim seat 5 (second seat portion 8B), and protrudes radially outward from the rim seat 5. When the solid tire 1 is mounted, such flange portion 6 supports the side surface of the solid tire 1 on the other side S2 in the tire axial direction.

[0018] [Solid tires] The solid tire 1 of this embodiment is configured to include a base rubber layer 11 and a tread rubber layer 12.

[0019] [Base rubber layer] The base rubber layer 11 is attached to the rim 2. An inner peripheral surface 13 in the tire radial direction of the base rubber layer 11 of this embodiment is disposed on the rim sheet 5 when attached to the rim 2. A protrusion 14 and a contact portion 15 are provided on the inner peripheral surface 13 of this embodiment.

[0020] The protrusions 14 of this embodiment protrude radially inward from one side S1 in the tire axial direction. These protrusions 14 are fitted into the recesses 7 when the solid tire 1 is mounted on the rim 2. This fixes (retains) the solid tire 1 (base rubber layer 11) to the rim 2. To ensure stable mounting of the solid tire 1 on the rim 2, the maximum height H4 of the protrusions 14 in the tire radial direction is set to, for example, 1.5% to 2.8% of the maximum height H2 of the tire cross section in the tire radial direction. In this specification, the dimensions of each part of the solid tire 1 are values measured before the tire is mounted on the rim 2.

[0021] The contact portion 15 of this embodiment is disposed on the other axial side S2 of the tire with respect to the protrusion 14. The contact portion 15 of this embodiment comes into contact with the radially outer surface of the seat portion 8 when mounted on the rim 2.

[0022] The contact portion 15 of this embodiment is configured to include a first contact portion 15A and a second contact portion 15B that is disposed on the other axial side S2 of the first contact portion 15A. The contact portion 15 may be configured with only one of the first contact portion 15A and the second contact portion 15B, or may further include other contact portions.

[0023] The second contact portion 15B of this embodiment is recessed radially outward relative to the first contact portion 15A (its inner diameter is set larger). The first contact portion 15A and the second contact portion 15B are connected via a step portion 15C. The first contact portion 15A of this embodiment abuts against the first seat portion 8A of the rim 2. The second contact portion 15B abuts against the second seat portion 8B of the rim 2.

[0024] In this embodiment, a plurality of (four in this embodiment) tension members 16 are embedded in the base rubber layer 11. Each tension member 16 is preferably formed in a ring shape that extends continuously in the tire circumferential direction. Such tension members 16 can enhance the stability of the solid tire 1 when mounted on the rim 2 by their hoop effect.

[0025] The base rubber layer 11 of this embodiment is configured to include a base inner circumferential layer 11A that includes the protrusions 14 and forms the inner circumferential surface 13 side, and a base outer circumferential layer 11B that is disposed radially outward of the base inner circumferential layer 11A. Details of the base inner circumferential layer 11A and the base outer circumferential layer 11B will be described later.

[0026] [Tread rubber layer] The tread rubber layer 12 has a tread surface 12S for contacting the road surface. The profile of the tread surface 12S in this embodiment has a symmetrical shape centered on the tire equator C, and is formed in an arc shape that convex outward in the tire radial direction.

[0027] [Installation of solid tires] In this embodiment, first, the solid tire 1 is inserted onto the rim 2 from one side S1 (the side of the recessed portion 7) to the other side S2 in the tire axial direction, and the protrusions 14 of the solid tire 1 are fitted into the recessed portions 7 of the rim 2. In this way, the solid tire 1 of this embodiment does not require the use of a side ring (not shown), and therefore can be easily mounted onto the rim 2.

[0028] In the solid tire 1 of this embodiment, the second contact portion 15B is recessed radially outward relative to the first contact portion 15A (the inner diameter is set larger). On the other hand, in the rim 2 of this embodiment, the first seat portion 8A is recessed radially inward relative to the second seat portion 8B (the outer diameter is set smaller). As a result, in this embodiment, the contact pressure between the second contact portion 15B and the first seat portion 8A can be reduced when the solid tire 1 is inserted onto the rim 2 from one side S1 (the recessed portion 7 side) toward the other side S2 in the tire axial direction. Therefore, in this embodiment, the solid tire 1 can be easily mounted on the rim 2.

[0029] [Vulcanization molding of solid tires] The solid tire 1 of this embodiment is manufactured by vulcanizing and molding an unvulcanized raw tire 1L, as is customary. Here, "unvulcanized" includes all states that have not yet reached complete vulcanization, and a so-called semi-vulcanized state is included in this "unvulcanized" state. A vulcanization mold is used for vulcanization molding. Figure 2 is a cross-sectional view showing the raw tire 1L and the vulcanization mold 21 of this embodiment.

[0030] The vulcanization mold 21 includes a pair of first molds 21A, 21A and a pair of second molds 21B, 21B. These first molds 21A, 21A and second molds 21B, 21B are set to be openable and closable.

[0031] The pair of first molds 21A, 21A of this embodiment are provided with first molding surfaces 22 for molding the tread surface 12S, sidewall side surfaces 17S, and portions of the bead side surfaces 18S of the solid tire 1. The pair of second molds 21B, 21B of this embodiment are provided with second molding surfaces 23 for molding portions of the bead side surfaces 18S and the inner circumferential surface 13 of the solid tire 1. Of the pair of second molds 21B, 21B, the second mold 21B arranged on one side S1 in the tire axial direction is provided with recesses 24 for molding the protrusions 14 of the solid tire 1.

[0032] When a pair of first molds 21A, 21A and a pair of second molds 21B, 21B are closed, a cavity 25 defined by molding surfaces (first molding surface 22 and second molding surface 23) spanning these molds 21A, 21B is formed in the vulcanization mold 21.

[0033] In the vulcanization molding step, the green tire 1L is placed in the vulcanization mold 21, in which the pair of first molds 21A, 21A and the pair of second molds 21B, 21B are open. Next, the pair of first molds 21A, 21A and the pair of second molds 21B, 21B are closed. The rubber material constituting the green tire 1L is plasticized by heat and pressure, and the green tire 1L is vulcanized and molded in the cavity 25. The recesses 24 of the second mold 21B are filled with the plasticized rubber material of the green tire 1L. In this way, a solid tire 1 (shown in FIG. 1) having protrusions 14 is manufactured.

[0034] However, if the fluidity of the rubber material constituting the base rubber layer 11 decreases during vulcanization molding, the plasticized rubber material will not flow sufficiently into the recesses 24, which will in turn lead to molding defects in the protrusions 14. On the other hand, simply using a rubber material with high fluidity will make it difficult to ensure the rigidity required for the solid tire 1.

[0035] In this embodiment, the base inner circumferential layer 11A and the base outer circumferential layer 11B are made of a first rubber material 31 and a second rubber material 32, which will be described below, thereby preventing poor molding of the protrusions 14 while maintaining the rigidity of the tire.

[0036] [Base inner layer] The base inner peripheral layer 11A is made of a first rubber material 31 that does not contain any fibers. In this embodiment, the fibers are used to reinforce the rubber material. Although such fibers can reinforce the rubber material, they tend to reduce the fluidity of the rubber material during vulcanization molding as shown in FIG. 2. Details of the fibers will be described later.

[0037] In this embodiment, the base rubber layer 11 that includes the protrusions 14 and forms the inner circumferential surface 13 is made of the first rubber material 31 that does not contain fibers, which improves the fluidity of the plasticized first rubber material 31 during vulcanization molding shown in FIG. 2. Therefore, in this embodiment, the first rubber material 31 can be sufficiently distributed throughout the cavity 25 of the vulcanization mold 21, thereby preventing molding defects of the protrusions 14. Furthermore, in this embodiment, the improved fluidity of the first rubber material 31 can also prevent molding defects of the first contact portion 15A and the second contact portion 15B that are connected via the step portion 15C.

[0038] [Base outer layer] The base outer peripheral layer 11B is made of a second rubber material 32 containing fibers.

[0039] Any fiber may be used as long as it can reinforce the rubber material. The fibers used in this embodiment include, for example, organic fibers (e.g., polyester fiber, nylon fiber, rayon fiber, polyethylene naphthalate fiber, and aramid fiber). One type of fiber may be blended into the second rubber material 32, or multiple types of fibers may be blended into the second rubber material 32. The second rubber material 32 may have the same composition as the first rubber material 31, or a different composition, except for the inclusion of the fiber. The composition of the first rubber material 31 and the second rubber material 32 may be appropriately determined based on the composition of rubber materials used in conventional base rubber layers.

[0040] The fiber length and fiber diameter can be set as appropriate. In this embodiment, the fiber length is preferably 10 mm or less, and more preferably 5 mm or less, taking into consideration the fluidity of the second rubber material 32 during vulcanization molding. Similarly, the fiber diameter is preferably 100 μm or less, and more preferably 50 μm or less.

[0041] In the solid tire 1 of this embodiment, the base outer circumferential layer 11B disposed radially outward of the base inner circumferential layer 11A is made of the second rubber material 32 containing fibers, and therefore has high rigidity due to the rubber reinforcing effect of the fibers. Furthermore, since the base outer circumferential layer 11B does not have components with complex shapes such as the protrusions 14, even if it is made of the second rubber material 32, which has lower fluidity than the first rubber material 31, no molding defects will occur during vulcanization molding as shown in Figure 2.

[0042] In this way, the solid tire 1 of this embodiment is able to maintain the rigidity of the tire while preventing poor molding of the protrusions 14 by virtue of the base rubber layer 11 including the base inner layer 11A made of the first rubber material 31 and the base outer layer 11B made of the second rubber material 32.

[0043] To effectively exert the above-mentioned effects, it is desirable that the rubber hardness of the first rubber material 31 be set to 70 to 95 degrees. By setting the rubber hardness to 70 degrees or more, the flowability of the first rubber material 31 is improved while the rigidity of the base inner circumferential layer 11A including the protrusions 14 can be maintained after vulcanization molding, and rim fixation (rim detachment prevention) can be improved. On the other hand, by setting the rubber hardness to 95 degrees or less, the rigidity of the protrusions 14 can be prevented from becoming higher than necessary, and therefore damage (breakage) to the protrusions 14 when mounted on the rim 2 can be prevented, for example. From this perspective, the rubber hardness is more preferably 75 degrees or more, and preferably 90 degrees or less.

[0044] In this specification, "rubber hardness" refers to a durometer A hardness measured at a standard temperature of 23°C ± 2°C using a durometer type A in accordance with JIS-K6253.

[0045] As shown in FIG. 1, the maximum height H1 of the base inner circumferential layer 11A in the tire radial direction is desirably set to 3% to 20% of the maximum tire cross-sectional height H2 in the tire radial direction. Setting the maximum height H1 to 3% or more of the maximum tire cross-sectional height H2 prevents the interface 19 between the base inner circumferential layer 11A and the base outer circumferential layer 11B from forming protrusions 14. This prevents damage to the interface 19 (e.g., peeling of the protrusions 14) during mounting on the rim 2, etc. On the other hand, setting the maximum height H1 to 20% or less of the maximum tire cross-sectional height H2 prevents the proportion of the base outer circumferential layer 11B from decreasing, thereby maintaining the rigidity of the tire. From this perspective, the maximum height H1 is preferably 5% or more, and more preferably 18% or less, of the maximum tire cross-sectional height H2.

[0046] The specific gravity of the second rubber material 32 is preferably set to 1.15 to 1.30. By setting the specific gravity to 1.15 or more, the reinforcing effect of the fibers can provide the base outer peripheral layer 11B with high rigidity, thereby improving steering stability. On the other hand, by setting the specific gravity to 1.30 or less, it is possible to prevent a decrease in the extensibility of the second rubber material 32 (base outer peripheral layer 11B), thereby maintaining the durability of the solid tire 1. From this perspective, the specific gravity is preferably 1.20 or more and preferably 1.25 or less. In the present embodiment, when no fibers are blended into the second rubber material 32, the specific gravity is 1.14 or less.

[0047] The maximum height H3 of the base outer peripheral layer 11B in the tire radial direction is desirably set to 15% to 80% of the maximum tire cross-sectional height H2 in the tire radial direction. By setting the maximum height H3 to 15% or more of the maximum tire cross-sectional height H2, the proportion of the highly rigid base outer peripheral layer 11B can be increased, thereby maintaining the tire rigidity and ultimately improving steering stability. On the other hand, by setting the maximum height H3 to 80% or less of the maximum tire cross-sectional height H2, it is possible to prevent the proportion of the tread rubber layer 12 (height in the tire radial direction) from decreasing, thereby preventing a shortening of the tire wear life and a decrease in durability. From this perspective, the maximum height H3 is preferably 35% or more, and preferably 60% or less, of the maximum tire cross-sectional height H2.

[0048] Although particularly preferred embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the illustrated embodiments and can be modified and implemented in various forms. [Example]

[0049] [Example A] The solid tire shown in FIG. 1 was prototyped based on the following specifications (Example 1). The base rubber layer of Example 1 included a base inner circumferential layer made of a first rubber material not blended with fibers, and a base outer circumferential layer made of a second rubber material blended with fibers. For comparison, a solid tire was prototyped (Comparative Example) that had a base rubber layer made only of a rubber material blended with fibers, similar to the tire substrate of Patent Document 1. Each prototype tire was then evaluated for the presence or absence of molding defects in the protrusions and tire rigidity (steering stability and durability). The common specifications and test methods are as follows. The test results are shown in Table 1. Tire size: 18x7-8 / 4.33 Rim size: 8 x 4.33R Maximum tire cross section height H2: 132mm Maximum height of protrusion H4 / H2: 2.8% Example 1: Base inner layer: Maximum height H1 / H2: 5% Rubber hardness of the first rubber: 80 degrees Base outer layer: Maximum height H3 / H2: 35% Second rubber: Specific gravity: 1.20 Fiber: Polyester fiber Comparative Example: Base rubber layer: Maximum height (H1+H3) / H2: 40%

[0050] <Whether or not there is a molding defect in the protrusion> 100 of each prototype tire were manufactured, and after vulcanization molding, the presence or absence of molding defects in the protrusions was visually confirmed.

[0051] <Handling stability> Each prototype tire was mounted on the above-mentioned rim and attached to all wheels of a vehicle (a counterweight-type 2.5-ton forklift), and loading and unloading work of a heavy load of about 2.0 tons was carried out. Then, the handling stability during the loading and unloading work was evaluated by the driver using a sensory evaluation. The evaluation is expressed as an index with Example 1 being 100, and the higher the number, the better the handling stability. Note that an evaluation of 90 or higher indicates that the desired handling stability is achieved and that the tire rigidity is maintained.

[0052] <Durability> After carrying out the above-mentioned loading and unloading work for 1000 hours, the occurrence of damage to the solid tire was visually confirmed. The evaluation was expressed as an index with Example 1 being 100, and the larger the index, the more the occurrence of damage was suppressed and the more excellent the durability. Note that an evaluation of 90 or higher indicates that the desired durability is achieved and the rigidity of the tire is maintained.

[0053] [Table 1]

[0054] As a result of the test, it was confirmed that the solid tire of Example 1 was able to maintain the rigidity of the tire while preventing molding defects in the protrusions, compared to the solid tire of the comparative example.

[0055] [Example B] Based on the specifications in Table 2, solid tires were prototyped (Examples 1 to 9) with different rubber hardnesses of the first rubber material and different maximum heights H1 of the base inner circumferential layer. Each prototype tire was evaluated for the presence or absence of molding defects in the protrusions and for its rigidity (steering stability and durability). Furthermore, each prototype tire was evaluated for its rim fixation and for the resistance to damage to the protrusions when mounted on the rim. The common specifications were the same as those of Example 1 (described in Example A) except for the specifications in Table 2. Furthermore, the presence or absence of molding defects in the protrusions and the rigidity of the tire (steering stability and durability) were as described in Example A.

[0056] <Rim fixation> After mounting each prototype tire on a rim, the stress required to pull each prototype tire from the rim was measured. The evaluation is expressed as an index with Example 1 being 100, with the higher the index, the better the rim fixation. Note that an evaluation of 90 or higher indicates that the desired rim fixation is achieved and that the tire rigidity is maintained.

[0057] <Damage resistance of protrusions> 100 units of each prototype tire were manufactured, and after vulcanization and molding, they were mounted on rims and visually inspected for damage to the protrusions. The evaluation is expressed as an index with Example 1 being 100, and the larger the index, the more damage is suppressed and the more durable the tire. An evaluation of 90 or higher indicates that the tire has the desired durability.

[0058] [Table 2]

[0059] The test results confirmed that the solid tires of Examples 1 to 9 maintained tire rigidity (steering stability and durability) while preventing molding defects in the protrusions. Furthermore, Examples 1, 3, 4, 7, and 8, which had the rubber hardness of the first rubber material and the maximum height H1 of the base inner circumferential layer within the preferred ranges, were able to improve steering stability, durability, and rim fixation, while suppressing damage to the protrusions when mounted on the rim, compared to the other Examples.

[0060] [Example C] Solid tires were prototyped (Example 1 and Examples 10 to 17) with different specific gravities of the second rubber material and different maximum heights H3 of the base outer peripheral layer based on the specifications in Table 3. Each prototype tire was evaluated for the presence or absence of molding defects in the protrusions, tire rigidity (steering stability and durability), rim fixation, and damage resistance of the protrusions when mounted on the rim. The common specifications were the same as those of Example 1 (described in Example A) except for the specifications in Table 3. The test methods were as described in Examples A and B.

[0061] [Table 3]

[0062] The test results confirmed that the solid tires of Examples 1, 11, 12, 15, and 16 maintained tire rigidity (steering stability and durability) while preventing molding defects in the protrusions. Furthermore, Examples 1, 11, 12, 15, and 16, in which the specific gravity of the second rubber material and the maximum height H3 of the base outer peripheral layer were within the preferred ranges, were able to improve steering stability and durability compared to the other Examples.

[0063] [Note] The present disclosure includes the following aspects.

[0064] [Disclosure 1] A solid tire, a base rubber layer attached to a side ring-less rim; and a tread rubber layer disposed radially outward of the base rubber layer, a protrusion protruding radially inward in the tire axial direction is provided on an inner circumferential surface of the base rubber layer on one side in the tire axial direction, the base rubber layer includes a base inner circumferential layer that includes the protrusions and forms the inner circumferential surface side, and a base outer circumferential layer that is disposed radially outward of the base inner circumferential layer, The base inner peripheral layer is made of a first rubber material that does not contain fibers, The base outer peripheral layer is made of a second rubber material containing fibers. Solid tires. [Disclosure 2] The solid tire according to Disclosure 1, wherein the first rubber material has a rubber hardness of 70 to 95 degrees. [Disclosure 3] The solid tire according to Disclosure 1 or 2, wherein the maximum height of the base inner circumferential layer in the tire radial direction is 3% to 20% of the maximum height of the tire cross section in the tire radial direction. [Disclosure 4] The solid tire according to any one of Disclosures 1 to 3, wherein the second rubber material has a specific gravity of 1.15 to 1.30. [Disclosure 5] The solid tire according to any one of Disclosures 1 to 4, wherein the maximum height of the outer peripheral base layer in the tire radial direction is 15% to 80% of the maximum height of the tire cross section in the tire radial direction. [Explanation of symbols]

[0065] 1 solid tire 2 Side ring-less rim 11 Base rubber layer 11A Base inner layer 11B Base outer layer 12 Tread rubber layer 13 Inner surface 14 Protrusion 31 First Rubber Material 32 Second rubber material

Claims

1. A solid tire, a base rubber layer attached to a side ring-less rim; and a tread rubber layer disposed radially outward of the base rubber layer, an inner circumferential surface of the base rubber layer in the tire radial direction includes a protruding portion located on one side in the tire axial direction and a contact portion located on the other side in the tire axial direction, the protruding portion protrudes radially inward from the contact portion, the base rubber layer includes a base inner circumferential layer that includes the protrusions and forms the inner circumferential surface side, and a base outer circumferential layer that is disposed radially outward of the base inner circumferential layer, the base inner peripheral layer is made of a first rubber material that does not contain fibers, The base outer peripheral layer is made of a second rubber material containing fibers, the fibers of the second rubber material have a fiber length of 10 mm or less and a fiber diameter of 100 μm or less, an interface between the base inner circumferential layer and the base outer circumferential layer is located radially outward of the contact portion, and is not formed within the protrusion; an annular tension member extending continuously in the tire circumferential direction is embedded in the base outer peripheral layer and is not provided in the base inner peripheral layer; Solid tires.

2. 2. The solid tire according to claim 1, wherein the first rubber material has a rubber hardness of 70 to 95 degrees.

3. 3. The solid tire according to claim 1, wherein the maximum height of the base inner layer in the tire radial direction is 3% to 20% of the maximum height of the tire cross section in the tire radial direction.

4. 4. The solid tire according to claim 1, wherein the specific gravity of the second rubber material is 1.15 to 1.

30.

5. 5. The solid tire according to claim 1, wherein the maximum height of the outer peripheral base layer in the tire radial direction is 15% to 80% of the maximum height of the tire cross section in the tire radial direction.

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