JP7571449B2 - Airless tire and method for manufacturing tire structure - Google Patents

Description

The present invention relates to a method for manufacturing an airless tire and a tire structure.

For example, Patent Document 1 discloses a tread ring structure including a tread rubber layer that forms the contact surface and a reinforcing rubber layer disposed radially inward of the tread rubber layer. This tread ring further includes an outer reinforcing cord layer disposed closest to the tread rubber layer, and an inner reinforcing cord layer disposed radially inward of the outer reinforcing cord layer. A reinforcing rubber layer is disposed between the outer reinforcing cord layer and the inner reinforcing cord layer.

Patent No. 6487779

The method disclosed in Patent Document 1 may not be able to suppress deformation of the tread ring due to tire lateral forces, i.e., forces in the tire width direction.

The present invention was made in consideration of these problems, and its purpose is to provide an airless tire and a method for manufacturing an airless tire that can suppress deformation of the tread ring due to forces in the tire width direction.

An airless tire according to one aspect of the present invention includes a tread ring having a contact surface that comes into contact with the ground. The tread ring includes a first reinforcing layer in which a plurality of first stiffening members are arranged in the tire width direction, and a second reinforcing layer in which a plurality of second stiffening members that add rigidity in the tire width direction are arranged in the tire circumferential direction. The distance from the tire rotation axis to the second stiffening member changes from one end to the other end of the second stiffening member.

The present invention makes it possible to suppress deformation of the tread ring due to forces in the tire width direction.

FIG. 1 is a side view showing an airless tire according to a first embodiment. FIG. 2 is a perspective cross-sectional view showing a main part of the airless tire shown in FIG. FIG. 3( a ) is a diagram showing a schematic cross-sectional structure of the tread ring taken along line AA in FIG. 1 , and FIG. 3( b ) is a diagram showing a schematic cross-sectional structure of the tread ring taken along line BB in FIG. 3( a ). FIG. 4 is an enlarged cross-sectional view of a region R1 in FIG. FIG. 5 is a diagram showing a main part of the cross-sectional structure of the tread ring taken along line CC in FIG. 6(a) and 6(b) are cross-sectional views that typically show the structure of a tread ring according to a first modified example. 7(a) and 7(b) are cross-sectional views that typically show the structure of a tread ring according to a first modified example. 8(a) to 8(c) are explanatory views showing a manufacturing process of the tread ring according to the first modified example. FIG. 9 is an explanatory diagram for explaining the step of FIG. 10(a) to 10(c) are explanatory views showing a manufacturing process of the tread ring according to the first modified example. FIG. 11( a ) is a cross-sectional view showing a tread ring applied to an airless tire according to a second embodiment, and FIG. 11( b ) is a cross-sectional view showing a cross-sectional structure of the tread ring taken along line DD in FIG. 11( a ). 12(a) and 12(b) are explanatory views showing the relationship between the first inclined stiffening member and the second inclined stiffening member. 13( a ) to 13 ( c ) are explanatory views showing a part of a manufacturing process for a tread ring that is applied to an airless tire according to a second modified example.

Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, identical parts are given the same reference numerals and the description will be omitted.

First Embodiment
The configuration of an airless tire 1 according to this embodiment will be described with reference to Figures 1 to 3. The airless tire 1 is composed of a wheel 2, a body 3, and a tread ring 4.

The wheel 2 is fixed to the axle via a hub provided on the vehicle. The wheel 2 has a disk shape and is fixed to the hub by a fastening means such as a bolt.

The body 3 is arranged concentrically on the radially inner side of the tread ring 4 and on the radially outer side of the wheel 2. The body is connected to the wheel 2 and the tread ring 4, and is an elastic support member that supports the tread ring 4 relative to the wheel 2. The body 3 is made of an elastically deformable material such as resin or rubber. The elastic deformation of the body 3 enables the airless tire 1 to support the weight of the vehicle and absorb impacts input from the ground.

The body 3 has an inner body ring 31, a number of spokes 32, and an outer body ring 33. The inner body ring 31, the number of spokes 32, and the outer body ring 33 are integrally formed.

The inner body ring 31 is disposed radially outward of the wheel 2. The inner body ring 31 has a cylindrical shape and is connected to the outer circumferential surface of the wheel 2.

The multiple spokes 32 connect the inner body ring 31 and the outer body ring 33. The multiple spokes 32 are arranged at a constant pitch along the tire circumferential direction and extend radially along the tire radial direction. The outer ends of the spokes 32 in the tire radial direction are connected to the outer body ring 33, and the inner ends of the spokes 32 in the tire radial direction are connected to the inner body ring 31.

A space is formed between a pair of circumferentially adjacent spokes 32, the inner body ring 31, and the outer body ring 33, but this space may be filled with a material different from the material forming the body 3.

The outer circumferential body ring 33 is disposed radially inward of the tread ring 4. The outer circumferential body ring 33 has a cylindrical shape, and the tread ring 4 is attached to the outer circumferential surface of the outer circumferential body ring 33.

When connecting the inner body ring 31 and the outer body ring 33, the structure is not limited to one in which multiple spokes 32 are arranged radially. It may be a cellular type having a honeycomb structure, or a void structure other than a radial shape.

The tread ring 4 is arranged concentrically on the radially outer side of the wheel 2, separated by the body 3. The tread ring 4 has a cylindrical shape, and the outer peripheral surface of the tread ring 4 becomes the contact surface that comes into contact with the ground. The force (driving force or braking force) generated on the vehicle side is transmitted to the ground via the wheel 2, the body 3, and the tread ring 4. When the airless tire is turned, the tread ring 4 generates a force (lateral force) in the tire rotation axis direction (tire width direction) due to a misalignment between the tire travel direction and the tire direction.

In an airless tire 1 having such a structure, the outer body ring 33 and the tread ring 4 are connected to each other and form an annular structure extending in the tire circumferential direction. In this annular structure, the outer body ring 33 corresponds to the inner layer of the annular structure, and the tread ring 4 corresponds to the outer layer of the annular structure.

The tread ring 4 will be described in detail with reference to Figures 3(a), 3(b), 4, and 5. The tread ring 4 is composed of an outer tread layer 41, an inner tread layer 42, and an intermediate tread layer 43.

The tread outer layer 41 is the outermost layer in the tread ring 4. The tread outer layer 41 has a cylindrical shape. The outer peripheral surface of the tread outer layer 41 is the contact surface, and the necessary tread pattern is provided on the contact surface.

The tread inner layer 42 is the innermost layer of the tread ring 4. The tread inner layer 42 has a cylindrical shape and is connected to the outer peripheral surface of the outer body ring 33.

The tread intermediate layer 43 is a layer located between the tread outer layer 41 and the tread inner layer 42 in the tread ring 4. The tread inner layer 42 has a cylindrical shape and is bonded to the tread outer layer 41 and the tread inner layer 42, respectively. The tread intermediate layer 43 has high rigidity in the tire width direction and tire circumferential direction.

The tread intermediate layer 43 is composed of a first annular reinforcing layer 430, a second annular reinforcing layer 440, an inclined reinforcing layer 450, and first and second refill layers 460a, 460b.

When viewed from the tire width direction (Fig. 3(b), Fig. 5), the first annular reinforcing layer 430 has a continuous annular shape along the tire circumferential direction. The first annular reinforcing layer 430 is located at the innermost position in the tire radial direction in the tread intermediate layer 43 and is connected to the tread inner layer 42. The first annular reinforcing layer 430 exists over the entire area of the tread intermediate layer 43 in the tire width direction. The first annular reinforcing layer 430 is composed of a first annular layer forming portion 431 and a plurality of first annular stiffening members 432 connected by the first annular layer forming portion 431.

The first annular layer forming portion 431 extends in the tire circumferential direction and connects a plurality of first annular stiffening members 432. The first annular layer forming portion 431 is formed from an elastically deformable material such as resin or rubber.

The multiple first annular stiffening members 432 are arranged at regular intervals in the tire width direction. The multiple first annular stiffening members 432 are provided over the entire area of the first annular layer forming portion 431 in the tire width direction. The multiple first annular stiffening members 432 may be arranged so as to be in close contact with each other in the tire width direction.

Each first annular stiffening member 432 is present inside the first annular layer forming portion 431 and extends in the tire circumferential direction in the same manner as the first annular layer forming portion 431. Each first annular stiffening member 432 is a member that adds rigidity in the tire circumferential direction to the tread intermediate layer 43 and, in turn, to the tread ring 4. The first annular stiffening member 432 is composed of a wire made of twisted metal wire, a wire made of a reinforcing fiber material, or the like.

The second annular reinforcing layer 440 has a continuous annular shape along the tire circumferential direction when viewed from the tire width direction (Figures 3(b) and 5). The second annular reinforcing layer 440 is located at the outermost position in the tire radial direction in the tread intermediate layer 43 and is connected to the tread outer peripheral layer 41. The second annular reinforcing layer 440 exists over the entire area of the tread intermediate layer 43 in the tire width direction. The second annular reinforcing layer 440 is composed of a second annular layer forming portion 441 and a plurality of second annular stiffening members 442 connected by the second annular layer forming portion 441.

The second annular layer forming portion 441 extends in the tire circumferential direction and connects multiple second annular stiffening members 442. The second annular layer forming portion 441 is made of an elastically deformable material such as resin or rubber.

The second annular stiffening members 442 are arranged at regular intervals in the tire width direction. The second annular stiffening members 442 are provided over the entire area of the second annular layer forming portion 441 in the tire width direction. The second annular stiffening members 442 may be arranged so as to be in close contact with each other in the tire width direction.

Each second annular stiffening member 442 is present inside the second annular layer forming portion 441 and extends in the tire circumferential direction in the same manner as the second annular layer forming portion 441. Each second annular stiffening member 442 is a member that adds rigidity in the tire circumferential direction to the tread intermediate layer 43 and, in turn, to the tread ring 4. The second annular stiffening member 442 is composed of a wire made of twisted metal or a wire made of a reinforcing fiber material.

When viewed from the tire width direction (Figures 3(b) and 5), the inclined reinforcement layer 450 is provided continuously along the tire circumferential direction. The inclined reinforcement layer 450 is located between the first annular reinforcement layer 430 and the second annular reinforcement layer 440 in the tread intermediate layer 43. The inclined reinforcement layer 450 exists over the entire area of the tread intermediate layer 43 in the tire width direction. The inclined reinforcement layer 450 is composed of an inclined layer forming portion 451 and a plurality of inclined stiffening members 452 connected by the inclined layer forming portion 451.

The inclined layer forming portion 451 extends in the tire circumferential direction and connects multiple inclined stiffening members 452. The inclined layer forming portion 451 is made of an elastically deformable material such as resin or rubber.

The multiple inclined stiffening members 452 are arranged at regular intervals in the tire circumferential direction. The multiple inclined stiffening members 452 are provided over the entire area of the inclined layer forming portion 451 in the tire circumferential direction. The multiple inclined stiffening members 452 may be arranged so as to be in close contact with each other in the tire width direction.

Each inclined stiffening member 452 is present inside the inclined layer forming portion 451 and extends parallel to the tire width direction. Each inclined stiffening member 452 is a member that adds rigidity in the tire width direction to the tread intermediate layer 43 and, in turn, to the tread ring 4. The inclined stiffening member 452 is composed of a wire made of twisted metal wire, a wire made of a reinforcing fiber material, or the like.

The inclined stiffening member 452 is provided over the entire area from the first end face 4a to the second end face 4b of the tread ring 4 in the tire width direction. The inclined stiffening member 452 extends linearly and is inclined with respect to the tire rotation axis when viewed in a cross section including the tire rotation axis (FIGS. 3(b) and 5). One end of the inclined stiffening member 452 located on the first end face 4a side is close to the first annular reinforcing layer 430, and the other end of the inclined stiffening member 452 located on the second end face 4b side is close to the second annular reinforcing layer 440. In other words, the distance to the tire rotation axis of the inclined stiffening member 452 changes from one end to the other end.

Each of the first and second refill layers 460a, 460b is continuously provided along the tire circumferential direction when viewed from the tire width direction. The first refill layer 460a is located between the first annular reinforcement layer 430 and the inclined reinforcement layer 450 in the tread intermediate layer 43. The second refill layer 460b is located between the inclined reinforcement layer 450 and the second annular reinforcement layer 440 in the tread intermediate layer 43. When viewed in a plane including the tire rotation axis, the cross sections of the first and second refill layers 460a, 460b each have a substantially triangular shape, and serve to fill the gaps between the layers. Each of the first and second refill layers 460a, 460b is formed from an elastically deformable material such as resin or rubber.

With a tread ring 4 configured in this way, the area ratio of the first and second annular stiffening members 432, 442 in the first and second annular reinforcing layers 430, 440 can be increased to improve the circumferential rigidity of the first and second annular reinforcing layers 430, 440.

In addition, by sandwiching the inclined reinforcement layer 450 between the first and second annular reinforcement layers 430, 440, the distance between the pair of annular reinforcement layers 430, 440 in the tire radial direction can be made wider. This increases the vertical rigidity of the tread ring 4, making it possible to suppress deformation of the tread ring 4 even if a force acts on the cylindrical tread ring 4 in a direction perpendicular to the tire rotation axis. This makes it possible to achieve both reduced rolling resistance and improved steering stability.

In addition, by increasing the area ratio of the inclined stiffening member 452 in the inclined reinforcement layer 450, the rigidity of the inclined reinforcement layer 450 in the tire width direction can be improved.

In addition, because an inclined reinforcing layer 450 is provided, the inclined stiffening member 452 extends over the entire area from the first end face 4a to the second end face 4b and is inclined with respect to the tire rotation axis.

By adopting such a structure, it is possible to suppress shear deformation of the first and second annular reinforcing layers 430, 440 against the tire lateral force acting on the tire contact surface. In other words, it is possible to increase the shear rigidity, and therefore it is possible to suppress deformation of the tread ring 4 against forces in the tire width direction. This makes it possible to suppress the decrease in cornering power, which is the tire's lateral force per unit side slip angle, and therefore it is possible to achieve both reduced rolling resistance and improved handling stability.

In addition, with this configuration, the inclined stiffening member 452 extends to the vicinity of the first end face 4a and the vicinity of the second end face 4b. Since deformation due to tire lateral force can be suppressed throughout the entire tread ring 4, tire lateral force can be generated throughout the entire tire contact surface. This makes it possible to suppress a decrease in the cornering power of the tire.

In this embodiment, the inclined stiffening member 452 is inclined linearly with respect to the tire rotation axis. However, the inclined stiffening member 452 is not limited to being inclined linearly.

Furthermore, it is sufficient that the distance from the inclined stiffening member 452 to the tire rotation axis changes from the first end face 4a to the second end face 4b. Below, variations of the inclined reinforcing layer 450 including the inclined layer forming portion 451 and the inclined stiffening member 452 are described.

First, the tread ring 4 of the airless tire 1 according to the first modified example will be described with reference to Figs. 6(a) and 6(b). In the first modified example, the inclined reinforcing layer 450 is divided at the center (one example of the intermediate portion) between the first end face 4a and the second end face 4b. The two divided inclined reinforcing layers 450 are bent at the center in the tire width direction and are inclined with respect to the tire rotation axis so that they are inclined in opposite directions.

In the example shown in FIG. 6(a), the bending point of the divided inclined reinforcement layer 450 is set on the tread inner layer 42 side. The inclined reinforcement layer 450 is inclined from this bending point toward the tread outer layer 41 side. On the other hand, in the example shown in FIG. 6(b), the bending point of the divided inclined reinforcement layer 450 is set on the tread outer layer 41 side. The inclined reinforcement layer 450 is inclined from this bending point toward the tread inner layer 42 side.

In the example shown in FIG. 6(a) and FIG. 6(b), only one layer of the inclined reinforcement layer 450 (hereinafter referred to as the "split type inclined reinforcement layer 450") split at the center in the tire width direction is provided in the tread intermediate layer 43. However, multiple layers of the split type inclined reinforcement layer 450 may be provided in the tread intermediate layer 43.

In the example shown in FIG. 7(a), split inclined reinforcement layers 450 are provided on the inner and outer sides of the tire radial direction. In the example shown in FIG. 7(a), the two split inclined reinforcement layers 450 are provided with inverse inclinations so that the bending points are close to each other in the center of the tire radial direction. The two split inclined reinforcement layers 450 are provided with inverse inclinations so that the bending points are close to each other in the center of the tire radial direction. In addition, a third refill layer 460c is provided between the two split inclined reinforcement layers 450 to fill the gap between the layers.

The two split inclined reinforcing layers 450 may be arranged with opposite inclinations so that the ends on the opposite side of the bending point are close to each other in the center of the tire radial direction.

Also, as shown in FIG. 7(b), the two divided inclined reinforcement layers 450 may be separated in the tire width direction, and a third annular reinforcement layer 455 may be provided between them. The third annular reinforcement layer 455 has a configuration corresponding to the first annular reinforcement layer 430 and the second annular reinforcement layer 440.

According to the configuration of the first modified example, the inclined reinforcement layer 450 has a structure that is approximately symmetrical with respect to the center in the tire width direction. Therefore, regardless of the difference in the direction of the tire lateral force, such as the leftward or rightward direction, deformation of the tread ring 4 due to a force in the tire width direction can be suppressed.

A method for manufacturing the tread ring 4 having the structure shown in FIG. 6(b) will be described with reference to FIGS. 8 to 10. The tread ring 4, which is a tire structure, is manufactured by feeding sheet-like material made of unvulcanized rubber along a predetermined feeding direction, stacking the sheets in order on the outer peripheral surface of a cylindrical frame 200, and vulcanizing each of the stacked sheet-like material. Note that in the process shown below, the process for stacking the outer peripheral tread layer 41 and the inner peripheral tread layer 42 is omitted for convenience.

In the first step, a first sheet material is fed and layered on the outer peripheral surface of the frame body 200. The first sheet material is formed of a plurality of first annular stiffening members 432 each extending in the feed direction, and unvulcanized rubber (first annular layer forming portion 431). As shown in FIG. 8(a), the first sheet material corresponds to the first annular reinforcing layer 430.

In the second step, the second sheet material is fed and laminated onto the outer peripheral surface of the first sheet material. The second sheet material has a pair of inclined surfaces with opposite inclinations on either side of a ridge line extending along the feed direction, and is made of unvulcanized rubber. The second sheet material is fed with the pair of inclined surfaces facing upward. As shown in FIG. 8(b), the second sheet material corresponds to the first refill layer 460a.

In the third step, the third sheet material is fed and layered on one of the inclined surfaces of the second sheet material. As shown in FIG. 9, the third sheet material is formed of a plurality of inclined stiffening members 452, each extending in a direction perpendicular to the feed direction, and unvulcanized rubber (inclined layer forming portion 451). As shown in FIG. 8(c) and FIG. 10(a), the third sheet material corresponds to one of the divided inclined reinforcing layers 450. Then, the third sheet material corresponding to the other divided inclined reinforcing layer 450 is layered on the other inclined surface of the second sheet material.

In the fourth step, a fourth sheet material is fed and laminated onto the outer peripheral surface of the third sheet material. The fourth sheet material has a concave surface corresponding to a pair of inclined surfaces of the third sheet material, and is made of unvulcanized rubber. As shown in FIG. 10(b), the fourth sheet material corresponds to the second refill layer 460b.

In the fifth step, the fifth sheet material is fed and laminated on the outer peripheral surface of the fourth sheet material. The fifth sheet material is formed of a plurality of second annular stiffening members 442, each extending in the feed direction, and unvulcanized rubber (second annular layer forming portion 441). As shown in FIG. 10(c), the fifth sheet material corresponds to the second annular reinforcing layer 440.

Through this series of steps, a cylindrical tread ring 4 is formed from unvulcanized rubber and stiffening material, and the tread ring 4 is vulcanized by applying heat and pressure, bonding each of the laminated sheet-like materials together to complete the tread ring 4 with the structure shown in Figure 6(b).

Once the tread ring 4 is manufactured, the body 3 is pressed and joined between the wheel 2 and the tread ring 4 to manufacture the airless tire 1. The body 3 is formed by various methods, such as podding, injection molding, and 3D printing.

According to this manufacturing method, the inclined stiffening member 452 crosses the tire width direction so that the distance to the tire rotation axis changes. This makes it possible to manufacture an airless tire that suppresses the decrease in the cornering power of the tire and achieves both reduced rolling resistance and steering stability.

Second Embodiment
The airless tire 1 according to the second embodiment will be described below. The airless tire 1 according to the second embodiment differs from that of the first embodiment in the structure of the tread ring 4. For convenience of description, the inclined stiffening member 452 shown in the first embodiment will be referred to as a first inclined stiffening member 452a below.

As shown in FIG. 11, the inclined reinforcing layer 450 is composed of a plurality of first inclined stiffening members 452a and a plurality of second inclined stiffening members 452b. The first inclined stiffening members 452a and the second inclined stiffening members 452b are arranged alternately in the tire circumferential direction. A third refill layer 460c is provided between the first inclined stiffening members 452a and the second inclined stiffening members 452b to fill the gap between the layers.

The configuration of the first inclined stiffening member 452a is as shown in the first embodiment. The configuration of the second inclined stiffening member 452b is also basically the same as the configuration of the first inclined stiffening member 452a, but differs in that the inclination of the second inclined stiffening member 452b with respect to the tire rotation axis is the opposite inclination to the inclination of the first inclined stiffening member 452a with respect to the tire rotation axis.

In FIG. 12(a), y is the distance from the origin in the tire axial direction, r is the distance from the origin in the tire radial direction, and θ is the tire rotation angle. In this embodiment, as shown in FIG. 12(a), the first inclined stiffening member 452a and the second inclined stiffening member 452b, which are adjacent to each other, are arranged so as to be parallel when viewed in the tire circumferential direction.

With this configuration, the first inclined stiffening member 452a and the second inclined stiffening member 452b extend to the vicinity of the first end face 4a and the vicinity of the second end face 4b. This makes it possible to suppress deformation of the entire tread ring 4 in response to tire lateral forces, allowing tire lateral forces to be generated across the entire tire contact surface. This makes it possible to suppress a decrease in the cornering power of the tire.

In addition, by arranging the first inclined stiffening member 452a and the second inclined stiffening member 452b at opposite inclinations, the deformation of the tread ring can be made the same whether the tire lateral force is generated to the right or the left. This makes it possible to suppress changes in cornering power due to differences in the direction of the tire lateral force.

As shown in FIG. 12(b), the first inclined stiffening member 452a and the second inclined stiffening member 452b that are adjacent to each other may be arranged so as to intersect when viewed in the tire circumferential direction. With this configuration, the first inclined stiffening member 452a and the second inclined stiffening member 452b can increase the rigidity in the tire circumferential direction. This can reduce the rolling resistance.

Next, a method for manufacturing the tread ring 4 having the structure shown in FIG. 11 will be described. The basic flow of the manufacturing method according to the second embodiment is the same as that shown in the first embodiment, and the first, second, and fifth steps are the same.

The third step will now be described in detail. As shown in FIG. 13(a), a stiffening member structure is prepared. The stiffening member structure is formed by inserting first inclined stiffening members 452a and second inclined stiffening members 452b, which are arranged alternately along the feed direction, into unvulcanized rubber 470 extending in the feed direction. Then, as shown in FIG. 13(b), the stiffening member structure is laminated along the ridge of the second sheet material, which corresponds to the first supplementary layer 460a.

Next, each of the first inclined stiffening members 452a is inclined along one of the pair of inclined surfaces. Also, each of the second inclined stiffening members 452b is inclined along the other of the pair of inclined surfaces.

Finally, as shown in FIG. 13(c), unvulcanized rubber (third refill layer 460c) extending in the feed direction is inserted into the gap between the first inclined stiffening member 452a and the second inclined stiffening member 452b from a direction perpendicular to the feed direction.

Then, in the fourth step, a fourth sheet material is fed and laminated on the outer peripheral surface of the stiffening member structure. The fourth sheet material has a pair of inclined surfaces with opposite inclinations on either side of a ridge line extending along the feed direction, and is made of unvulcanized rubber. The fourth sheet material is fed with the pair of inclined surfaces facing downward. The second sheet material corresponds to the second refill layer 460b.

Through the above steps, a cylindrical tread ring 4 is formed from unvulcanized rubber and stiffening material, and the tread ring 4 is vulcanized by applying heat and pressure, bonding each of the laminated sheet-like materials together to complete the tread ring 4 with the structure shown in Figure 11.

In FIG. 13(c), there are gaps between adjacent first inclined stiffening members 452a and between adjacent second inclined stiffening members 452b, but these spaces disappear when the unvulcanized tread ring 4 is vulcanized, and no space is created inside the inclined reinforcing layer 450.

According to this manufacturing method, the first inclined stiffening member 452a and the second inclined stiffening member 452b cross the tire width direction so that the distance to the tire rotation axis changes. This makes it possible to manufacture an airless tire that suppresses a decrease in the cornering power of the tire and achieves both reduced rolling resistance and steering stability.

As described above, an embodiment of the present invention has been described, but the descriptions and drawings that form part of this disclosure should not be understood as limiting this invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

1 Airless tire 2 Wheel 3 Body 4 Tread ring 4a First end surface 4b Second end surface 31 Inner body ring 32 Spoke 33 Outer body ring 41 Tread outer layer 42 Tread inner layer 43 Tread intermediate layer 430 First annular reinforcing layer (first reinforcing layer)
431 First annular layer forming portion 432 First annular stiffening member (first stiffening member)
440 Second annular reinforcing layer (first reinforcing layer)
441: Second annular layer forming portion 442: Second annular stiffening member (first stiffening member)
450 Sloped reinforcing layer (second reinforcing layer)
451: inclined layer forming portion 452: inclined stiffening member (second stiffening member)
452a First inclined stiffening member (second stiffening member)
452b Second inclined stiffening member (third stiffening member)
455 Third annular reinforcing layer 460a First fill layer 460b Second fill layer 460c Third fill layer 200 Frame body

Claims (9)

A tread ring is disposed concentrically on the outer side in the tire radial direction of a wheel to which an axle of a vehicle is fixed, the tread ring having a contact surface that comes into contact with the ground;
a body arranged concentrically on the tire radially inner side of the tread ring and on the wheel radially outer side of the wheel, the body supporting the tread ring relative to the wheel,
The tread ring is
a first reinforcing layer in which a plurality of first stiffening members extending in a tire circumferential direction and adding rigidity in the tire circumferential direction are arranged in a tire width direction;
a second stiffening member extending between a first end surface and a second end surface of the tread ring in the tire width direction to add rigidity in the tire width direction; and a second reinforcing layer arranged in a plurality of second stiffening members in the tire circumferential direction,
The second stiffening member is
an airless tire in which a distance to the first reinforcing layer changes from one end to the other end of the second stiffening member; The airless tire according to claim 1 , wherein the first reinforcing layer is disposed on an outer side and an inner side in the tire radial direction of the second reinforcing layer. The second stiffening member is
The airless tire according to claim 1 or 2, wherein the protrusion extends linearly over the entire area from the first end surface to the second end surface and is inclined with respect to a tire rotation axis. The second stiffening member is
the first end surface and the second end surface are separated into two portions at an intermediate portion, each portion being inclined with respect to the tire rotation axis;
The airless tire according to claim 1 or 2, wherein the second stiffening member is divided into two parts, is bent at the intermediate portion, and has opposite inclinations with respect to the tire rotation axis. The second reinforcing layer is
The tire further includes a third stiffening member that is disposed in a circumferential direction of the tire and extends between the first end surface and the second end surface,
The third stiffening member is
the first end surface extends linearly from the first end surface to the second end surface along the tire width direction and is inclined with respect to the tire rotation axis;
The airless tire according to claim 3 , wherein an inclination of the third stiffening member with respect to the tire rotation axis is opposite to an inclination of the second stiffening member with respect to the tire rotation axis. The second stiffening members and the third stiffening members are alternately arranged in a tire circumferential direction,
The airless tire according to claim 5 , wherein the second stiffening member and the third stiffening member that are adjacent to each other are arranged so as to be parallel to each other when viewed in the tire circumferential direction. The second stiffening members and the third stiffening members are alternately arranged in a tire circumferential direction,
The airless tire according to claim 5 , wherein the second stiffening member and the third stiffening member that are adjacent to each other are arranged so as to intersect when viewed in the tire circumferential direction. A method for manufacturing a tire structure by feeding sheet-like materials made of unvulcanized rubber along a predetermined feeding direction, stacking them in order on a cylindrical frame, and vulcanizing each of the stacked materials, comprising the steps of:
a step of feeding a first sheet material formed of a plurality of first stiffening members and unvulcanized rubber, each of which extends in the feeding direction, and laminating the first sheet material on an outer peripheral surface of the frame;
a step of feeding a second sheet-like material formed of unvulcanized rubber, the second sheet-like material having a pair of inclined surfaces with inverse inclinations with respect to a ridge line extending along the feeding direction as a boundary, and laminating the second sheet-like material on an outer peripheral surface of the first sheet-like material;
and laminating a third sheet-like material formed of a plurality of second stiffening members and unvulcanized rubber, each of which extends in a direction perpendicular to the feed direction, onto each of the pair of inclined surfaces. A method for manufacturing a tire structure by feeding sheet-like materials made of unvulcanized rubber along a predetermined feeding direction, laminating them in order on an outer peripheral surface of a cylindrical frame, and vulcanizing each of the laminated materials, comprising:
a step of feeding a first sheet material formed of a plurality of first stiffening members and unvulcanized rubber, each of which extends in the feeding direction, and laminating the first sheet material on an outer peripheral surface of the frame;
a step of feeding a second sheet-like material formed of unvulcanized rubber, the second sheet-like material having a pair of inclined surfaces with inverse inclinations with respect to a ridge line extending along the feeding direction as a boundary, and laminating the second sheet-like material on an outer peripheral surface of the first sheet-like material;
a step of stacking stiffening member structures, in which second stiffening members and third stiffening members arranged alternately along the feeding direction are inserted into unvulcanized rubber extending in the feeding direction, along the ridge line;
inclining each of the second stiffening members along one of the pair of inclined surfaces, and inclining each of the third stiffening members along the other of the pair of inclined surfaces.

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