JP2022182137A - airless tire - Google Patents

Abstract

To provide an airless tire in which the shape change of a tread ring caused by cooling after vulcanization molding is suppressed, and which therefore enables improvement of durability performance thereof.SOLUTION: An airless tire 1 is provided, comprising: a tread ring 2 having a ground contact surface 2a; a hub 3 disposed inside in a tire radial direction, of the tread ring 2 and fixed to an axle; and a spoke 4 for connecting the tread ring 2 and the hub 3 to each other. The tread ring 2 includes an outside reinforcement layer 6 disposed at the side of the ground contact surface 2a and an inside reinforcement layer 7 disposed inside the outside reinforcement layer 6 in the tire redial direction at intervals. The outside reinforcement layer 6 includes at least one outside ply 8 in which an outside reinforcement cord 8a is disposed, and the inside reinforcement layer 7 includes at least one inside ply 9 in which an inside reinforcement cord 9a is disposed. The angle θ2 of the inside reinforcement cord 9a with respect to a tire circumferential direction is larger than the angle θ1 of the outside reinforcement cord 8a with respect to the tire circumferential direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to an airless tire that can support a load by its own structure without using high pressure air.

Conventionally, various airless tires are known in which a tread ring and a hub are connected with spokes. For example, Patent Literature 1 below proposes an airless tire including a cylindrical tread ring having a contact surface, a hub fixed to an axle, and spokes made of a polymer material.

JP 2016-130071 A

However, in the tread ring of Patent Document 1, the inner peripheral surface of the tread ring is convexly curved outward in the tire radial direction in the cross section of the meridian of the tire due to contraction of the rubber due to cooling after vulcanization molding. was there. In such a tread ring, a force acts to separate the adhesive surface with the spokes, and there is a risk that the durability performance of the heiress tire is lowered.

The present invention has been devised in view of the actual situation as described above, and the main object of the present invention is to provide an airless tire that can improve durability performance by suppressing the shape change of the tread ring due to cooling after vulcanization molding. there is

The present invention relates to an airless tire, comprising a tread ring having a ground contact surface, a hub disposed radially inside the tread ring and fixed to an axle, and connecting the tread ring and the hub. The tread ring includes an outer reinforcing layer arranged on the side of the ground contact surface, and an inner reinforcing layer arranged at a distance inside the outer reinforcing layer in the tire radial direction, The outer reinforcing layer includes at least one outer ply having outer reinforcing cords arranged thereon, the inner reinforcing layer includes at least one inner ply having inner reinforcing cords arranged thereon, and the tire of the inner reinforcing cords The angle with respect to the circumferential direction is larger than the angle of the outer reinforcing cord with respect to the tire circumferential direction.

In the heiress tire of the present invention, the outer ply is arranged adjacent to the first outer ply on the inner side of the first outer ply in the tire radial direction and the first outer ply arranged on the side of the ground contact surface. and a second outer ply, wherein the outer reinforcing cords of the first outer ply and the outer reinforcing cords of the second outer ply are inclined at the same angle in opposite directions to each other with respect to the tire circumferential direction. It is desirable to be

In the heiress tire of the present invention, the inner ply includes a first inner ply arranged on the side of the spoke, and an outer side of the first inner ply in the tire radial direction and adjacent to the first inner ply. and a second inner ply, wherein the inner reinforcing cords of the first inner ply and the inner reinforcing cords of the second inner ply are inclined at the same angle in opposite directions to the tire circumferential direction. is desirable.

In the heiress tire of the present invention, the tread ring includes an outer rubber layer on which the ground contact surface is formed, an inner rubber layer in contact with the spokes, and an intermediate layer disposed between the outer rubber layer and the inner rubber layer. a rubber layer, wherein the outer reinforcing layer is disposed between the intermediate rubber layer and the outer rubber layer, and the inner reinforcing layer is disposed between the intermediate rubber layer and the inner rubber layer. is desirable.

In the heiress tire of the present invention, the tread ring includes a pair of sides connecting the outer rubber layer and the inner rubber layer on both sides of the intermediate rubber layer, the outer reinforcing layer, and the inner reinforcing layer in the axial direction of the tire. It preferably contains wall rubber.

In the heiress tire of the present invention, it is desirable that the molding shrinkage of the outer rubber layer is larger than the molding shrinkage of the intermediate rubber layer.

In the heiress tire of the present invention, it is preferable that the thickness of the outer rubber layer in the tire radial direction is larger than the thickness of the inner rubber layer in the tire radial direction.

In the heiress tire of the present invention, the tread ring includes an outer reinforcing layer arranged on the side of the ground contact surface, and an inner reinforcing layer arranged at a distance inside the outer reinforcing layer in the tire radial direction, The outer reinforcing layer includes at least one outer ply with outer reinforcing cords arranged thereon, the inner reinforcing layer includes at least one inner ply with inner reinforcing cords arranged thereon, and the inner reinforcing cords extend around the tire circumference. The angle with respect to the direction is larger than the angle of the outer reinforcing cord with respect to the tire circumferential direction.

Such a tread ring can suppress contraction in the tire axial direction on the radially inner side of the tire due to cooling after vulcanization molding, and can maintain the inner peripheral surface in a flat state in the tire meridian cross section. Therefore, in the heiress tire of the present invention, it is possible to suppress shape change of the tread ring due to cooling after vulcanization molding, improve adhesion to the spokes, and improve durability performance.

It is a perspective view showing one embodiment of the heiress tire of the present invention. It is a side view of an airless tire. 1 is a partial cross-sectional perspective view of a tread ring and spokes; FIG. It is a tire meridian sectional view of a tread ring. FIG. 4 is a developed plan view showing the internal structure of the tread ring;

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a perspective view showing an heiress tire 1 of this embodiment, and FIG. 2 is a side view of the heiress tire 1. As shown in FIG. As shown in FIGS. 1 and 2, the heiress tire 1 of the present embodiment includes a tread ring 2 having a ground contact surface 2a, a hub 3 arranged inside the tread ring 2 in the tire radial direction, and the tread ring 2. and spokes 4 for connecting the hub 3.

Hub 3 preferably includes a fixed portion 3a that is fixed to an axle (not shown) of the vehicle. Such an heiress tire 1 can support a load acting on the tread ring 2 by means of the hub 3 and the spokes 4 without using high pressure air. Therefore, the heiress tire 1 of the present embodiment is free from the risk of puncture.

The spokes 4 include, for example, a plurality of plate-like spoke plates 5 each having a width in the tire axial direction greater than a thickness in the tire circumferential direction. In such spokes 4, when a load acts on the tread ring 2, a tensile force acts on the spoke plates 5 positioned above the hub 3, and a compressive force acts on the spoke plates 5 positioned below the hub 3. can support the load.

3 is a partial sectional perspective view of the tread ring 2 and the spokes 4, and FIG. 4 is a tire meridian sectional view of the tread ring 2. As shown in FIG. As shown in FIGS. 3 and 4, the tread ring 2 of this embodiment includes an outer reinforcing layer 6 disposed on the side of the ground contact surface 2a between the ground contact surface 2a and the inner peripheral surface 2b, and an outer reinforcing layer 6. and an inner reinforcing layer 7 spaced radially inward of the layer 6 .

FIG. 5 is a developed plan view showing the internal structure of the tread ring 2. As shown in FIG. As shown in FIGS. 3-5, the outer reinforcing layer 6 of this embodiment includes at least one outer ply 8 having outer reinforcing cords 8a disposed thereon. The inner reinforcing layer 7 of this embodiment includes at least one inner ply 9 on which inner reinforcing cords 9a are arranged.

The angle θ2 of the inner reinforcing cords 9a with respect to the tire circumferential direction in this embodiment is larger than the angle θ1 of the outer reinforcing cords 8a with respect to the tire circumferential direction. Such a tread ring 2 can suppress contraction in the tire axial direction on the inner side in the tire radial direction due to cooling after vulcanization molding, and can maintain the inner peripheral surface 2b in a flat state in the tire meridian cross section. Therefore, in the heiress tire 1 of the present embodiment, it is possible to suppress shape change of the tread ring 2 due to cooling after vulcanization molding, improve adhesiveness with the spokes 4, and improve durability performance.

As a more preferable aspect, the outer ply 8 is arranged adjacent to the first outer ply 8A on the inner side of the first outer ply 8A in the tire radial direction and the first outer ply 8A arranged on the side of the ground contact surface 2a. and a second outer ply 8B.

The outer reinforcing cords 8a of the first outer ply 8A and the outer reinforcing cords 8a of the second outer ply 8B in this embodiment are inclined at the same angle θ1 in opposite directions with respect to the tire circumferential direction. The outer reinforcing cords 8a are made of, for example, metal cords, organic fiber cords, or the like. The outer reinforcing cords 8a of the first outer ply 8A and the outer reinforcing cords 8a of the second outer ply 8B are preferably made of the same material. Such an outer reinforcing layer 6 is excellent in balance in the tire axial direction, and can improve the steering stability performance of the heiress tire 1 .

The inner ply 9 includes a first inner ply 9A arranged on the side of the inner peripheral surface 2b in contact with the spokes 4, and an outer side of the first inner ply 9A in the tire radial direction and adjacent to the first inner ply 9A. A second inner ply 9B is preferably included.

The inner reinforcing cords 9a of the first inner ply 9A and the inner reinforcing cords 9a of the second inner ply 9B of the present embodiment are inclined at the same angle θ2 in opposite directions with respect to the tire circumferential direction. The inner reinforcing cords 9a are made of, for example, metal cords, organic fiber cords, or the like. The inner reinforcing cords 9a of the first inner ply 9A and the inner reinforcing cords 9a of the second inner ply 9B are preferably made of the same material. Such an inner reinforcing layer 7 is excellent in balance in the tire axial direction, and can improve the steering stability performance of the heiress tire 1 .

As shown in FIGS. 3 to 5, the tread ring 2 includes an outer rubber layer 10 formed with a contact surface 2a, an inner rubber layer 11 formed with an inner peripheral surface 2b contacting the spokes 4, and an outer rubber layer 10 and an intermediate rubber layer 12 disposed between the inner rubber layer 11 . By adjusting the rubber materials of the outer rubber layer 10, the inner rubber layer 11, and the intermediate rubber layer 12, such a tread ring 2 can achieve both durability performance and ride comfort performance of the heiress tire 1.

The outer reinforcing layer 6 of this embodiment is arranged between the intermediate rubber layer 12 and the outer rubber layer 10 . The inner reinforcing layer 7 of this embodiment is arranged between the intermediate rubber layer 12 and the inner rubber layer 11 . Such outer reinforcing layer 6 and inner reinforcing layer 7 can increase the rigidity of the tread ring 2 and improve the durability performance and steering stability performance of the heiress tire 1 .

The tread ring 2 includes a sidewall rubber 13 connecting the outer rubber layer 10 and the inner rubber layer 11 on at least one side of the intermediate rubber layer 12, the outer reinforcing layer 6 and the inner reinforcing layer 7 in the tire axial direction. .

The tread ring 2 of this embodiment includes a pair of sidewall rubbers 13 connecting the outer rubber layer 10 and the inner rubber layer 11 on both sides of the intermediate rubber layer 12, the outer reinforcing layer 6 and the inner reinforcing layer 7 in the tire axial direction. contains. In such a tread ring 2, the intermediate rubber layer 12, the outer reinforcing layer 6, and the inner reinforcing layer 7 do not come into contact with external obstacles or the like, and the durability performance of the heiress tire 1 can be improved.

The mold shrinkage rate of the outer rubber layer 10 of this embodiment is larger than the mold shrinkage rate of the intermediate rubber layer 12 . Here, the molding shrinkage rate is the rate at which rubber shrinks with cooling after vulcanization molding. Such a tread ring 2 suppresses contraction in the tire axial direction on the inner side in the tire radial direction due to cooling after vulcanization molding, and is useful for maintaining the inner peripheral surface 2b in a flat state in the tire meridian cross section.

As shown in FIG. 4, the thickness t1 of the outer rubber layer 10 in the tire radial direction at the tire equator C of the present embodiment is larger than the thickness t2 of the inner rubber layer 11 in the tire radial direction. In such a tread ring 2, even when the outer rubber layer 10 and the inner rubber layer 11 are made of a rubber material having the same molding shrinkage rate, the difference in thickness makes it possible to create a difference in shrinkage force. It helps to keep the circumferential surface 2b flat in the tire meridian section.

As shown in FIGS. 1 and 3 to 5, the tread ring 2 has a plurality of circumferential grooves 14 extending in the tire circumferential direction, two in this embodiment, on a ground contact surface 2a that contacts the road surface during running. formed. Such a tread ring 2 has good drainage properties, and can improve the wet performance of the heiress tire 1 . The ground plane 2a is not limited to such an aspect, and may be, for example, block-shaped, or may be formed with a plurality of recesses.

As shown in FIGS. 1 and 2, the hub 3 is made of a non-elastic material such as metal. The hub 3 preferably has a disk-shaped fixing portion 3a fixed to the axle and a cylindrical cylindrical portion 3b connected to the spokes 4. As shown in FIG. The fixing portion 3a of the hub 3 is formed with, for example, a plurality of fixing holes. The fixing portion 3a of the hub 3 is not limited to such a mode, and may be, for example, one that can be attached to a dedicated axle with one touch.

As shown in FIGS. 1-3, the spokes 4 are made of, for example, an elastic polymeric material. The polymeric material is desirably selected appropriately from a single elastomer, a composite elastomer of two or more kinds, an elastomer containing fibers, and the like. Such spokes 4 have an excellent balance of weight reduction, flexibility, and strength, and are useful for improving the fuel efficiency performance, ride comfort performance, and durability performance of the heiress tire 1 in a well-balanced manner.

The spokes 4 of this embodiment include a plurality of spoke plates 5 , an outer cylindrical portion 15 connected to the tread ring 2 and an inner cylindrical portion 16 connected to the hub 3 . Thereby, each spoke plate 5 is indirectly connected to the tread ring 2 and the hub 3 .

Such spokes 4 can be firmly connected to the hub 3 and the tread ring 2, and the durability performance of the heiress tire 1 can be improved. It should be noted that the spokes 4 may, for example, omit the outer cylindrical portion 15 and the inner cylindrical portion 16 and each of the spoke plates 5 may be directly connected to the tread ring 2 and the hub 3 .

Each of the spoke plates 5 is preferably curved in a substantially S-shape when viewed from the tire axial direction. Such spokes 4 can be easily deformed when a compressive force is applied, and can reduce the impact at the time of grounding, so that the ride comfort performance of the heiress tire 1 can be improved.

The spoke plate 5 includes a first spoke plate 5A arranged on one side in the tire axial direction and a second spoke plate 5B arranged on the other side when viewed from the thickness direction of the spoke plate 5 . The first spoke plates 5A and the second spoke plates 5B are arranged alternately in the tire circumferential direction, for example. Such spoke plates 5 can achieve both weight reduction and balance in the axial direction of the tire, and can achieve both low fuel consumption performance and steering stability performance of the heiress tire 1 .

Each of the spoke plates 5 preferably extends obliquely with respect to the tire axial direction. Such spokes 4 can improve the rigidity in the tire circumferential direction and improve the durability performance of the heiress tire 1 .

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and can be implemented in various modified forms.

A tread ring of the airless tire shown in FIGS. In Table 1, the inclination of each reinforcing cord in one direction with respect to the tire circumferential direction is indicated by +, and the inclination in the other direction is indicated by -. Using a prototype tread ring, a change in shape of the tread ring due to cooling after vulcanization molding with a core having a flat tire meridian cross section was tested. The main common specifications and test methods are as follows.

<Common specifications>
Tread ring width: 155.0mm
Tread ring outer diameter: 524.0mm
Tread ring inner diameter: 476.8mm
Outer rubber layer thickness: 7.0mm
Inner rubber layer thickness: 0.8mm

<Test method>
The tread ring cooled after vulcanization molding was photographed by CT, and the radius of curvature of the inner peripheral surface in the tire meridian cross section was measured. The results are expressed as an index with Comparative Example 1 being 100. A larger value indicates a larger radius of curvature and a flatter surface.

The results of the tests are shown in Table 1.

As a result of the test, the tread ring of the example has a tire meridian cross section that is almost flat compared to the comparative example, suppresses the shape change of the tread ring due to cooling after vulcanization molding, and improves the adhesion to the spokes. It was confirmed that the durability performance of the airless tire could be improved.

Reference Signs List 1 airless tire 2 tread ring 2a ground contact surface 3 hub 4 spokes 6 outer reinforcing layer 7 inner reinforcing layer 8 outer ply 8a outer reinforcing cord 9 inner ply 9a inner reinforcing cord

Claims (7)

It is an airless tire,
A tread ring having a ground contact surface, a hub arranged inside the tread ring in the tire radial direction and fixed to an axle, and spokes for connecting the tread ring and the hub,
The tread ring includes an outer reinforcing layer arranged on the side of the ground contact surface, and an inner reinforcing layer arranged at a distance inside the outer reinforcing layer in the tire radial direction,
the outer reinforcing layer includes at least one outer ply having outer reinforcing cords arranged thereon;
The inner reinforcing layer includes at least one inner ply having inner reinforcing cords arranged thereon,
The angle of the inner reinforcing cord with respect to the tire circumferential direction is greater than the angle of the outer reinforcing cord with respect to the tire circumferential direction,
airless tires. The outer ply includes a first outer ply arranged on the side of the ground contact surface and a second outer ply arranged adjacent to the first outer ply inside the first outer ply in the tire radial direction. including
The heiress according to claim 1, wherein the outer reinforcing cords of the first outer ply and the outer reinforcing cords of the second outer ply are inclined at the same angle in opposite directions with respect to the tire circumferential direction. tire. The inner ply includes a first inner ply arranged on the spoke side, and a second inner ply arranged adjacent to the first inner ply outside the first inner ply in the tire radial direction. ,
3. The inner reinforcing cord of the first inner ply and the inner reinforcing cord of the second inner ply are inclined at the same angle in opposite directions with respect to the tire circumferential direction. airless tires. The tread ring includes an outer rubber layer on which the ground contact surface is formed, an inner rubber layer in contact with the spokes, and an intermediate rubber layer disposed between the outer rubber layer and the inner rubber layer,
The outer reinforcing layer is arranged between the intermediate rubber layer and the outer rubber layer,
The heiress tire according to any one of claims 1 to 3, wherein the inner reinforcing layer is arranged between the intermediate rubber layer and the inner rubber layer. The tread ring includes a pair of sidewall rubbers connecting the outer rubber layer and the inner rubber layer on both sides of the intermediate rubber layer, the outer reinforcing layer, and the inner reinforcing layer in the axial direction of the tire. 4. The airless tire according to 4. The heiress tire according to claim 4 or 5, wherein the molding shrinkage of the outer rubber layer is larger than the molding shrinkage of the intermediate rubber layer. The heiress tire according to any one of claims 4 to 6, wherein the thickness of the outer rubber layer in the tire radial direction is greater than the thickness of the inner rubber layer in the tire radial direction.

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