WO2019102918A1

WO2019102918A1 - Run-flat tire

Info

Publication number: WO2019102918A1
Application number: PCT/JP2018/042149
Authority: WO
Inventors: 龍之介松山
Original assignee: 株式会社ブリヂストン
Priority date: 2017-11-27
Filing date: 2018-11-14
Publication date: 2019-05-31
Also published as: JP6909715B2; JP2019094017A

Abstract

This run-flat tire includes: a tire body; an elastic support body that is joined to the inner surface of a bead portion of the tire body in the tire width direction, protrudes outward in the tire radial direction while separated from a tire side portion, and is curved in the tire width direction; and a fiber reinforcing layer formed in the curved part of the elastic support body, at a position near a surface with a large radius curvature.

Description

Run flat tire

The present disclosure relates to run flat tires.

Japanese Patent Application Laid-Open No. 2013-95369 discloses a side reinforced type run flat tire in which the tire side portion is reinforced with a side reinforcing rubber, and the durability during run flat running (that is, abnormal running with lowered air pressure) is secured. It is done.

In the run flat tire provided with the side reinforcing rubber as shown in the above-mentioned Japanese Patent Application Laid-Open No. 2013-95369, the buckling of the tire side portion during run flat running is suppressed, but the vertical spring during running is large. Tend to be

The present disclosure provides a run flat tire in which the vertical spring during normal driving is unlikely to be large.

The run flat tire according to the first aspect is joined to the tire body and the inner surface of the bead portion of the tire body in the tire width direction, protrudes outward in the tire radial direction in a state of being separated from the tire side portion, and curves in the tire width direction And a fiber-reinforcing layer formed on the curved portion of the elastic support near the surface having a large radius of curvature.

In the run flat tire according to the first aspect, the elastic support is joined to the inner surface in the tire width direction of the bead portion in the tire main body. The elastic support protrudes in the tire radial direction and curves in the tire width direction. For this reason, when the air pressure decreases, the curved portion of the elastic support and the inner circumferential surface of the tire come into contact, and the elastic support is pressed from the tire. A fiber reinforcing layer is formed on the curved portion of the elastic support near the surface having a large radius of curvature. For this reason, compared with the case where the fiber reinforcement layer is not formed, the rigidity of the elastic support is enhanced, and the elastic support is not easily deformed by the pressure from the tire. As a result, the pneumatic tire can run on a run flat.

Further, since the elastic support is disposed apart from the tire side portion, it is difficult to affect the rigidity of the tire side portion. For this reason, compared with the run flat tire provided with the side reinforcement rubber, the vertical spring at the time of normal running does not easily become large.

A run flat tire according to a second aspect is the run flat tire according to the first aspect, wherein the elastic support is annularly formed along the tire circumferential direction.

In the run flat tire according to the second aspect, the elastic support is formed annularly along the tire circumferential direction. Thus, the elastic support is less likely to be deformed by an external force along the tire radial direction, as compared to the case where the elastic support is not formed annularly. For this reason, the durability during run flat running is high.

The run flat tire according to a third aspect is the run flat tire according to the first aspect or the second aspect, wherein the elastic support is curved outward in the tire width direction.

In the run flat tire according to the third aspect, the elastic support is curved outward in the tire width direction. Therefore, when the curved portion of the elastic support is pressed from the inner circumferential surface of the tire, the tire main body tends to move outward in the tire width direction by the frictional force generated between the curved portion and the inner circumferential surface of the tire. . As a result, the bead portion is pressed against the rim, and the rim removal during run flat travel is suppressed.

A run flat tire according to a fourth aspect is the run flat tire according to any one of the first to third aspects, wherein the elastic support is positioned on the inner side of the rim in the tire width direction of the bead portion. It is joined to the part to

In the run-flat tire according to the fourth aspect, the portion of the elastic support joined to the bead portion is located on the inner side in the tire width direction of the rim. For this reason, vibration and fluttering at the time of normal traveling are smaller than, for example, the case where the elastic support is joined to the tire side portion. This can suppress an increase in rolling resistance during normal driving.

A run flat tire according to a fifth aspect is the run flat tire according to any one of the first to fourth aspects, wherein the elastic support is formed using an elastomer, and the fiber reinforcing layer is formed using an organic fiber. It is formed.

In the run flat tire according to the fifth aspect, the elastic support is formed using an elastomer. For this reason, compared with the elastic body formed using metal etc., elasticity is low and lightweight. Therefore, when the curved portion contacts the tire, the inner circumferential surface of the tire is less likely to be damaged. Moreover, since the fiber reinforcement layer is formed using organic fiber, it is lightweight compared with a steel wire etc.

A run flat tire according to a sixth aspect is the run flat tire according to any one of the first to fifth aspects, wherein the elastic support is formed of a single material.

In the run flat tire according to the sixth aspect, the elastic support is formed of a single material. For this reason, compared with the case where several materials are combined and an elastic support body is formed, manufacture is easy.

A run flat tire according to a seventh aspect is the run flat tire according to any one of the first to sixth aspects, wherein a diameter of a fiber of the fiber forming the fiber reinforcing layer is viewed from the direction along the axial direction of the tire. The inclination angle with respect to the direction is -20 ° or more and 20 ° or less.

In the run-flat tire according to the seventh aspect, the inclination angle of the fibers forming the fiber reinforcing layer with respect to the tire radial direction is set to −20 ° or more and 20 ° or less. For this reason, compared with the case where it is smaller than -20 ° or larger than 20 °, the resistance that resists the tensile force generated in the side portion of the elastic support in the cross section along the tire width direction and the tire radial direction Is high.

According to the run flat tire according to the present disclosure, the vertical spring during normal travel is unlikely to be large.

1 is a half sectional view showing a run flat tire according to a first embodiment of the present disclosure. 1 is a partial perspective view showing a run flat tire according to a first embodiment of the present disclosure. 1 is a partial elevation view showing a stepping-in side of a run flat tire according to a first embodiment of the present disclosure during run flat running. It is a fragmentary sectional view showing the state at the time of run flat running of the run flat tire concerning a 1st embodiment of this indication. It is a half section view showing the run flat tire concerning a 2nd embodiment of this indication. It is a fragmentary sectional view showing the state at the time of run flat running of the run flat tire concerning a 2nd embodiment of this indication. It is a fragmentary sectional view showing the state where a run flat tire concerning a 2nd embodiment of this indication is turning run at the time of run flat running. The run flat tire which concerns on 2nd Embodiment of this indication WHEREIN: It is a half cross-sectional view which shows the modification which joined the elastic support body to the bead part in the tire width direction inner part of a rim | limb. It is a table | surface which shows the performance test result of the tire to which the support body which concerns on 1st Embodiment of this indication was applied, and the tire which concerns on a comparative example.

First Embodiment
Hereinafter, an embodiment which is an example of a pneumatic tire according to the present disclosure will be described in detail with reference to the drawings as appropriate. Components indicated by the same reference numerals in the drawings mean that they are the same components. Further, each component is not limited to one, and a plurality of components may exist. Note that duplicate explanations and symbols in the embodiments described below may be omitted. Note that the present disclosure is not limited to the following embodiments at all, and can be implemented with appropriate modifications within the scope of the purpose of the present disclosure.

FIG. 1 shows a tire main body (hereinafter referred to as “tire 10”) of a pneumatic tire according to a first embodiment of the present disclosure. The tire 10 is a run flat tire that can travel even in a state where the air pressure is reduced by an elastic support 40 described later.

In FIG. 1, a cut surface (that is, a cross section seen from the direction along the tire circumferential direction) cut along the tire width direction and the tire radial direction of the tire 10 is shown. In the drawings, arrow W indicates the width direction (tire width direction) of the tire 10, and arrow R indicates the radial direction of the tire 10 (tire radial direction). The tire width direction referred to here indicates a direction parallel to the rotation axis of the tire 10. Further, the tire radial direction means a direction orthogonal to the rotation axis of the tire 10. Moreover, the code | symbol CL has shown the equatorial plane (tire equatorial plane) of the tire 10. As shown in FIG.

Further, in the present embodiment, the side closer to the rotation axis of the tire 10 along the tire radial direction is “inward in the tire radial direction”, and the side farther from the rotation axis of the tire 10 along the tire radial direction is “the outer side in the tire radial direction” And write. On the other hand, the side closer to the tire equatorial plane CL along the tire width direction will be referred to as "the inner side in the tire width direction", and the side farther from the tire equatorial plane CL along the tire width direction will be referred to as "the outer side in the tire width direction".

<Tire>
FIG. 1 shows a tire 10 assembled to a rim 30 which is a standard rim and filled with a standard air pressure. The term "standard rim" as used herein refers to the rim specified in the Year Book 2017 edition of JATMA (Japan Automobile Tire Association). Further, the standard air pressure is an air pressure corresponding to the maximum load capacity of JATMA (Japan Automobile Tires Association) Year Book 2017 edition.

As shown in FIG. 1, the tire 10 includes a pair of bead portions 12, a carcass 14 disposed across the bead cores 26 embedded in the bead portions 12, and a bead core 26 embedded in the bead portions 12 from the tire radial direction. A bead filler 28 extending outward along the outer surface of the carcass 14, a belt layer 16 provided on the tire radial direction outer side of the carcass 14, and a tread 20 provided on the tire radial direction outer side of the belt layer 16 There is.

A tread 20 that constitutes an outer peripheral portion of the tire 10 is provided on the tire radial direction outer side of the belt layer 16. The tire side portion 22 is configured by a sidewall lower portion 22A on the bead portion 12 side and a sidewall upper portion 22B on the tread 20 side, and connects the bead portion 12 and the tread 20.

(Bead part)
Bead cores 26 which are wire bundles are embedded in the pair of bead portions 12 respectively. A carcass 14 straddles these bead cores 26. The bead core 26 can adopt various structures in a pneumatic tire such as a circular cross section or a polygonal shape, and for example, a hexagonal can be adopted as a polygon, but in the present embodiment, it is a quadrangle. There is.

As shown in FIG. 1, in the region surrounded by the carcass 14 of the bead portion 12 (that is, the region outside the portion of the carcass 14 disposed inward in the tire width direction around the bead core 26), An outwardly extending bead filler 28 is embedded.

(Carcass)
The carcass (carcass ply) 14 is a tire frame member formed by covering a plurality of cords with a covering rubber. The carcass 14 extends in a toroidal shape from one bead core 26 to the other bead core 26 to form a tire skeleton.

In the present embodiment, the carcass 14 is a radial carcass. The material of the carcass 14 is not particularly limited, and rayon, nylon, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), aramid, glass fiber, carbon fiber, steel or the like can be adopted. In terms of weight reduction, organic fiber cords are preferred. Further, although the number of implanted carcasses is in the range of 20 to 60/50 mm, it is not limited to this range.

(Belt layer)
A belt layer 16 is disposed on the tire radial direction outer side of the carcass 14. The belt layer 16 is composed of two belt plies 16A and 16B. The belt plies 16A and 16B are each formed by coating a plurality of cords (for example, organic fiber cords and metal cords) with a covering rubber. The cords constituting the belt plies 16A, 16B extend in a direction inclined with respect to the tire circumferential direction.

(tread)
A tread 20 is provided on the outer side in the tire radial direction of the belt layer 16. The tread 20 is a portion that contacts the road surface during traveling. A plurality of circumferential grooves 24 extending in the tire circumferential direction are formed on the tread surface of the tread 20. The shape and the number of the circumferential grooves 24 are appropriately set in accordance with the performance required for the tire 10 such as drainage performance and steering stability.

<Elastic support>
As shown in FIG. 2, the elastic support 40 is a tire support member formed in an annular (i.e., annular) shape along the tire circumferential direction. Although the elastic support body 40 is shown in FIG. 1 and 2 as being disposed on one side in the tire width direction, the elastic support 40 is similarly disposed on the other side in the tire width direction.

The elastic support body 40 is formed by arranging the elastic body 42 and the fiber reinforcing layer 44 in a layered manner. The elastic body 42 is adhesively bonded to the bead portion 12 located in the tire width direction inner portion of the rim 30 in a cross sectional view along the tire width direction and the tire radial direction. More specifically, at least a portion of the elastic body 42 is adhesively bonded to the inner side surface of the bead portion 12 in a region radially inward of the tire N from the point N in FIG. The point N is the tire width direction outer end and tire radial direction outer end of the portion where the rim 30 and the bead portion 12 are in contact.

The elastic body 42 extends outward in the tire radial direction from the portion joined to the bead portion 12 and is curved inward in the tire width direction. And in the curved part of elastic body 42, fiber reinforcement layer 44 is joined to the field (surface 42A on the convex side) with a large curvature radius.

In the following description, the convex side surface (surface with a large radius of curvature) of the elastic support 40, the elastic body 42, and the fiber reinforcing layer 44 is the outer surface, and the surface with a concave side (surface with a small radius of curvature) is inner It is called the side.

The elastic body 42 is a main body member of the elastic support body 40, and is formed using the same rubber as the tire 10. The fiber reinforcing layer 44 is a cord layer formed by coating a plurality of organic fiber cords (for example, an aromatic polyamide cord) with the same rubber as the elastic body 42. The rubber constituting the fiber reinforcing layer 44 is fused with the rubber constituting the elastic body 42. Thereby, the elastic support body 40 has a configuration in which the organic fiber cord is embedded in the rubber. In the following description, the organic fiber cord is simply referred to as a cord 44A (see FIG. 3).

As shown in FIG. 1, the elastic support 40 is disposed such that the convex side surface 42 </ b> A of the elastic body 42 and the fiber reinforcing layer 44 face the outer side in the tire radial direction or the outer side in the width direction. Further, the elastic support 40 is disposed apart from the inner peripheral surface 22C of the tire side portion 22 except for the joint portion with the bead portion 12, and the elastic support 40 and the inner peripheral surface 22C of the tire side portion 22 are disposed. A space V is formed between them.

FIG. 3 shows a partially enlarged view of the tread side of the tire 10 during runflat running. Also, in FIG. 3, the cord 44A embedded in the rubber in the fiber reinforcing layer 44 is shown by a dotted line. The cords 44A are formed to intersect with the radial direction of the tire 10 and the elastic support 40 at an angle θ. The angle θ is set to −20 ° ≦ θ ≦ 20 ° with a positive value when the cord 44A is inclined in the rotational direction shown by the arrow R in FIG. For example, θ in FIG. 3 is about −10 °.

<Function>
In the tire 10 to which the elastic support 40 according to the first embodiment is applied, as shown in FIG. 4, when the air pressure decreases, the outer peripheral surface of the elastic support 40 and the inner peripheral surface of the tire 10 are curved in a convex shape. And contact. At this time, the elastic support 40 is pressed inward in the tire radial direction from the tire 10.

Since the fiber reinforcing layer 44 is formed on the elastic body 42 constituting the elastic support body 40, the pressing force from the tire 10 is higher than in the case where the fiber reinforcing layer 44 is not formed. It is difficult to deform against. Thus, the pneumatic tire can travel even when the internal pressure is zero. That is, run flat driving is possible.

In addition, compressive stress and tensile stress are generated inside the elastic support body 40 by deformation of the elastic body 42. Specifically, a compressive stress is generated at a place where the elastic body 42 is deformed in a direction in which the elastic body 42 receives an external force, and a tensile stress is generated at a place where the elastic body 42 is deformed in the extending direction.

For example, as shown in FIG. 4, when the elastic support 40 receives an external force P1 in a direction along the tire radial direction from the tire 10, a tensile stress TB is generated on the side portion 40B of the outer surface of the elastic support 40.

In the elastic support 40 according to the present embodiment, the fiber reinforcing layer 44 is joined along the convexly curved outer peripheral surface of the elastic body 42. That is, the fiber reinforcing layer 44 is disposed along the outer surface of the elastic support 40. As a result, the cords 44A (see FIG. 3) embedded in the fiber reinforcing layer 44 can resist the tensile stress TB.

The deformation of the elastic support 40 is suppressed by the cords 44A resisting the tensile stress TB. For this reason, the elastic support body 40 resists the external force P1, and the tire 10 can run run flat.

Further, the elastic body 42 is formed using rubber. For this reason, compared with the case where a support body is formed using metal etc., it is hard to damage the inner peripheral surface of the tire 10, and is lightweight. Furthermore, since the fiber reinforcing layer 44 is formed using the organic fiber cord (code 44A), it is lightweight compared to the case of using a steel wire or the like.

In addition, since the elastic body 42 is formed of a single material (rubber), it is easy to manufacture as compared with the case where a plurality of materials are combined and formed.

Further, as shown in FIG. 1, since the elastic body 42 is disposed apart from the inner circumferential surface 22 C of the tire side portion 22, the rigidity of the tire side portion 22 is hardly affected. For this reason, as compared with the run flat tire provided with the side reinforcing rubber in contact with the inner circumferential surface 22C of the tire side portion 22, the vertical spring during normal running is unlikely to be large. Further, compared to a run flat tire having side reinforcing rubber in the tire side portion 22, heat is less likely to be generated from the tire side portion during run flat running, and the generated heat is less likely to be accumulated. This increases runflat durability. In addition, fuel efficiency during normal driving is improved.

Further, as shown in FIG. 3, the cords 44A forming the fiber reinforcing layer 44 are inclined with respect to the tire radial direction and the radial direction of the elastic support 40. For this reason, at the time of run flat running, it is possible to resist the tensile force TD acting along the tire circumferential direction on the tread-in side and the kick-out side. Thereby, the durability of the elastic support 40 is enhanced.

Further, the inclination angle of the cord 44A with respect to the tire radial direction is set to −20 ° or more and 20 ° or less. For this reason, compared with the case where it is smaller than −20 ° or larger than 20 °, the resistance to the tensile stress TB (see FIG. 4) generated in the side portion 40B of the elastic support 40 is high.

In the present embodiment, the elastic body 42 is entirely curved, and the fiber reinforcing layer 44 is formed on substantially the entire outer surface of the elastic body 42. Thereby, as compared with the case where the fiber reinforcing layer 44 is formed only on a part of the outer side surface of the elastic body 42, the deformation of the elastic support 40 can be efficiently suppressed.

However, the embodiment of the present disclosure is not limited thereto, and the fiber reinforcing layer 44 may be formed at a position where the largest tensile stress may be generated during run flat travel. Specifically, for example, the outer surface of the elastic body 42 may be formed at a position including a portion (point M shown in FIG. 1) at which the tangent line coincides with the tire radial direction.

By forming the fiber reinforcing layer 44 in such a position, deformation of the elastic support 40 can be efficiently suppressed. In addition, the fiber reinforcing layer 44 may be embedded not in the outer surface of the elastic body 42 but in the inside as long as the elastic body 42 receives a tensile force when the elastic body 42 is pressed from the tire 10. When the fiber reinforcing layer 44 is embedded in the elastic body 42, the fiber reinforcing layer 44 is embedded at a position closer to the outer peripheral surface than the inner peripheral surface of the elastic body 42 (that is, closer to the surface having a large radius of curvature).

Furthermore, the inclination angle of the cord 44A with respect to the tire radial direction may be smaller than −20 ° or larger than 20 °, as necessary. In this case, it is possible to easily resist the tensile force TD acting along the tire circumferential direction.

Second Embodiment
<Support>
As shown in FIG. 1, the elastic support 40 in the first embodiment is curved inward in the tire width direction. On the other hand, as shown in FIG. 5, the elastic support 50 in the second embodiment is curved outward in the tire width direction. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

The elastic support 50 is formed by arranging the elastic body 52 and the fiber reinforcing layer 54 in layers. The elastic body 52 is adhesively bonded to the bead portion 12 located at the tire radial direction outer portion of the rim 30 in a cross sectional view along the tire width direction and the tire radial direction. More specifically, at least a part of the elastic body 52 is joined to the inner side surface of the bead portion 12 in a region radially outward and inward in the tire width direction from the point N in FIG.

The elastic body 52 extends outward in the tire radial direction from a portion joined to the bead portion 12 and is curved outward in the tire width direction. Then, in the curved portion of the elastic body 52, the fiber reinforcing layer 54 is joined along the surface having a large radius of curvature (that is, the surface 52A on the convex side).

In the following description, the surface on the convex side of the elastic support 50, the elastic body 52, and the fiber reinforcing layer 54 (that is, the surface having a large radius of curvature) is the outer surface, and the surface on the concave side (a surface having a small radius of curvature). It is called the inner side. The "outside surface" and the "inside surface" do not indicate the outer surface and the inner surface in the tire width direction.

Like the elastic body 42, the elastic body 52 is a main body member of the elastic support body 50, and is formed using the same rubber as the rubber that forms the tire 10. Further, the fiber reinforcing layer 54 is a cord layer formed by covering a plurality of organic fiber cords with the same rubber as the elastic body 52, similarly to the fiber reinforcing layer 44.

As shown in FIG. 5, the elastic support 50 is disposed such that the surface 52 </ b> A on the convex side of the elastic body 52 and the fiber reinforcing layer 54 face the outer side in the tire radial direction or the inner side in the width direction. Further, the elastic support 50 is disposed apart from the inner peripheral surface 22C of the tire side portion 22, and a space V is formed between the elastic support 40 and the inner peripheral surface 22C of the tire side portion 22. There is.

<Function>
As shown in FIG. 6A, when the elastic support 50 in the second embodiment receives an external force P2 in a direction along the tire radial direction from the tire 10, tensile stress is applied to the side portion 50B of the outer surface of the elastic support 50. TB occurs. At this time, the cord embedded in the fiber reinforcing layer 54 can resist the tensile stress TB. Since the deformation of the elastic support 50 is thereby suppressed, the elastic support 50 resists the external force P2, and the tire 10 can run flat.

In addition, the elastic support 50 is curved outward in the tire width direction. Therefore, when the elastic support 50 receives the external force P2 from the tire 10, as shown by the broken line and the arrow L in FIG. 6A, the elastic support 50 tries to move outward in the tire width direction, and the bead portion 12 of the tire 10 is moved to the rim 30. Press As a result, the tire 10 is less likely to come off the rim.

In the second embodiment, the elastic support 50 is adhesively bonded to the bead portion 12 at the tire radial direction outer portion of the rim 30. For this reason, as shown in FIG. 6B, the elastic support 50 can form a compression bundle between the rim 30 and the ground contact end of the tire 10, for example, at the time of turning operation, etc. to support the load.

Further, by bonding the elastic support 50 to the tire radial direction outer portion, the volumes of the elastic body 52 and the fiber reinforcing layer 54 can be reduced as compared with the case of bonding to the tire width direction inner portion of the rim 30. Thereby, the weight of the tire 10 can be reduced.

In the present embodiment, the elastic support 50 curved outward in the tire width direction is joined to the bead portion 12 at the tire radial direction outer portion of the rim 30, but the embodiment of the present disclosure is not limited thereto. .

For example, as shown in FIG. 7, the elastic support 60 curved outward in the tire width direction is joined to the bead portion 12 at the tire width direction inner portion of the rim 30 in the same manner as the elastic support 40 of the first embodiment. It is also good. In the bead portion 12, the degree of fixation to the rim 30 is higher in the tire width direction inner portion than in the tire radial direction outer portion of the rim 30, and it is difficult for the tire to scatter during normal travel. For this reason, rolling resistance can be reduced.

[performance test]
In order to verify the performance of the tire 10 to which the elastic support 40 in the above embodiment is applied, the pneumatic tire of Example 1 below and the pneumatic tires of Comparative Examples 1 and 2 not included in the present disclosure are prepared. Test was conducted.

The comparative example 1 is a normal tire which does not adhere | attach a side reinforcement rubber to a tire side part, without using any of the

elastic support bodies

40, 50, and 60 in the said embodiment. The comparative example 2 is a run flat tire reinforced by bonding side reinforcing rubber to the inner peripheral surface 22C of the tire side portion 22 without using any of the

elastic supports

40, 50, 60.

A tire having a tire size of 205/55 RF1691 V was used as the tire 10 in Example 1 and the pneumatic tire in Comparative Examples 1 and 2. In the test, a drum endurance test according to ISO1692 was performed at a traveling speed of 80 km / h in a state where tire wheels with an air pressure of 0 kPa were disposed on a drum tester and a load of 4.02 kN was applied. This evaluated RF performance (ie, run flat durability). Also, a separate test was conducted to evaluate the fuel efficiency, comfort, and moment of inertia at the time of internal pressure filling. Comfort was evaluated by measuring the longitudinal spring property.

As shown in FIG. 8, Example 1 and Comparative Example 2 have high RF performance compared to Comparative Example 1. And it turned out that Example 1 is high in RF performance compared with comparative example 2. In addition, it was found that the fuel efficiency, the comfort, and the moment of inertia of the example 1 are superior to those of the comparative example 2. The numerical values in FIG. 7 are evaluation indexes, and the RF performance, fuel efficiency, and comfort are better as the index is larger, and the moment of inertia is better as the index is smaller.

[Modification]
In each of the above embodiments, the

elastic supports

40 and 50 are formed in an annular shape along the tire circumferential direction, but the embodiments of the present disclosure are not limited thereto. For example, the

elastic supports

40 and 50 may be formed at intervals along the circumferential direction. Thereby, the vertical spring of the tire 10 can be reduced.

In the first embodiment, rubber (that is, vulcanized rubber) is used for the elastic body 42 and the fiber reinforcing layer 44, but the embodiment of the present disclosure is not limited thereto. For example, in addition to general purpose resins such as thermoplastic resin, thermosetting resin, and (meth) acrylic resin, EVA resin, vinyl chloride resin, fluorocarbon resin, silicone resin, engineering plastics (including super engineering plastics), etc. It can be used. The same applies to the

elastic bodies

52 and 62 and the

fiber reinforcing layers

54 and 64 in the second embodiment. In addition, in order to form

elastic body

42, 52, 62, these materials may be used independently and may be used in combination.

A thermoplastic resin (including a thermoplastic elastomer) refers to a polymer compound which softens and flows as the temperature rises and becomes relatively hard and strong when cooled. In the present specification, among these, the material softens and flows as temperature rises, and becomes relatively hard and strong when cooled, and the polymer compound having rubbery elasticity is a thermoplastic elastomer, and the material increases as temperature rises. When the polymer compound softens, flows, cools, it becomes a relatively hard and strong state, and a polymer compound having no rubbery elasticity is distinguished as a non-elastomeric thermoplastic resin.

Examples of thermoplastic resins (including thermoplastic elastomers) include polyolefin thermoplastic elastomer (TPO), polystyrene thermoplastic elastomer (TPS), polyamide thermoplastic elastomer (TPA), polyurethane thermoplastic elastomer (TPU), polyester And thermoplastic thermoplastic elastomers (TPV) and thermoplastic olefin resins, polystyrene thermoplastic resins, polyamide thermoplastic resins and polyester thermoplastic resins.

Moreover, although the organic fiber cord is used as a cord which forms

fiber reinforcement layer

44, 54, 64 in the above-mentioned embodiment, an embodiment of this indication is not limited to this. For example, a steel cord may be used. This steel cord is based on steel and can contain various minor inclusions such as carbon, manganese, silicon, phosphorus, sulfur, copper, chromium and the like.

In addition, as the various cords, a monofilament cord or a cord in which a plurality of filaments are twisted can be used. Various designs can be adopted for the twist structure, and various cross-section structures, twist pitches, twist directions, and distances between adjacent filaments can be used. Furthermore, by adopting a cord in which filaments of different materials are twisted, the cross-sectional structure is not particularly limited, and various twist structures such as single twist, layer twist, and double twist can be taken.

Furthermore, the fiber reinforcing layer may be configured using FRP (fiber reinforced plastic) instead of the cord coated with resin or the like. As fibers applied to FRP, glass fibers, carbon fibers, boron fibers, aramid fibers and the like can be appropriately selected. Thus, the present disclosure can be implemented in various ways.

The disclosure of Japanese Patent Application 2017-227007 filed November 27, 2017 is incorporated herein by reference in its entirety. All documents, patent applications and technical standards described herein are as specific and individually as individual documents, patent applications and technical standards are incorporated by reference. Incorporated herein by reference.

Claims

The tire body,
An elastic support that is joined to the tire width direction inner side surface of the bead portion in the tire main body, protrudes outward in the tire radial direction in a state of being separated from the tire side portion, and curves in the tire width direction;
A fiber reinforcing layer formed in the curved portion of the elastic support near the surface having a large radius of curvature;
Run flat tires with
The run flat tire according to claim 1, wherein the elastic support is annularly formed along the tire circumferential direction.
The run flat tire according to claim 1, wherein the elastic support is curved outward in the tire width direction.
The elastic support is joined to a portion of the bead portion located on the inner side in the tire width direction of the rim in a state where the tire main body is assembled to the rim. Run flat tires described in.
The run flat tire according to any one of claims 1 to 4, wherein the elastic support is formed using an elastomer, and the fiber reinforcing layer is formed using an organic fiber.
The run flat tire according to any one of claims 1 to 5, wherein the elastic support is formed of a single material.
The inclination angle with respect to the tire radial direction of the fiber which forms the said fiber reinforcement layer seeing from the direction along a tire axial direction is -20 degrees or more, 20 degrees or less, It is described in any one of Claims 1-6. Run flat tires.