Airless tires

Abstract

To enable the manufacturing of the airless tire body using relatively small equipment. [Solution] An airless tire comprising a wheel 10 for mounting to a vehicle, a plurality of spokes 22 which are elastic members and are periodically arranged in the circumferential direction on the outer circumference of the wheel, an intermediate ring 24 which is an elastic member and is arranged in the circumferential direction and connects adjacent spokes in the circumferential direction, and a body portion 20 which consists of spokes and an intermediate ring, and a tread ring 30 which is an elastic support member and is arranged on the outermost circumference of the spokes, wherein the body portion is formed from a plurality of divided body portions 21 which are divided in the radial direction, and has an inner bend portion 27 near the outer bend portion 26 of the spokes and intermediate ring.

Description

Technical Field

[0001] The present invention relates to a non-pneumatic tire.

Background Art

[0002] As an example of a non-pneumatic tire that does not use air, the tire described in Patent Document 1 is known. This conventional tire includes an annular outer surface, an annular inner surface, and a plurality of spokes extending between the outer surface and the inner surface in a plurality of spoke rings including a first spoke ring adjacent to a second spoke ring. The first spoke ring has a first rigidity, the second spoke ring has a second rigidity different from the first rigidity, and includes a tread layer extending circumferentially around the annular outer surface of the plurality of spoke rings.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Such non-pneumatic tires are often manufactured using a molding machine with a mold for the body portion located outside the wheel. The body portion includes spokes, intermediate rings, and the like. The inventors of the present invention have focused on the fact that a relatively large amount of material is poured into the mold at one time in the manufacture of non-pneumatic tires, which requires a relatively large device.

[0005] An object of the present invention is to enable the body portion of a non-pneumatic tire to be manufactured by a relatively small device.

Means for Solving the Problems

[0006] One aspect of the present invention comprises a wheel, spokes, an intermediate ring, a body portion, and a tread ring. The wheel is provided to be coupled to a vehicle. The spokes are arranged periodically on the outer circumference of the wheel, include elastic members, and are composed of multiple spokes. The intermediate ring is arranged circumferentially, connects adjacent spokes in the circumferential direction, and includes elastic members. The body portion consists of spokes and intermediate rings. The tread ring is arranged on the outermost circumference of the spokes and is configured as an elastic support member. The body portion is formed from a plurality of radially divided body portions, and connecting portions are provided near the joints between the spokes and the intermediate rings.

[0007] According to the above-mentioned airless tire, the body of the airless tire can be manufactured using relatively small equipment. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing an airless tire according to an embodiment. [Figure 2] This is a schematic diagram showing the spokes, inner spoke rings, intermediate rings, and outer spoke rings that make up an airless tire. [Figure 3] This is a schematic diagram showing the portion indicated by the dashed line in Figure 2. [Figure 4] This is a schematic diagram showing adjacent partitioned bodies in the radial direction. [Figure 5] This is a schematic diagram showing adjacent partitioned bodies in the radial direction. [Figure 6] This is a schematic diagram showing the divided body portion in the second embodiment. [Figure 7] This is a schematic diagram showing a segmented body section related to a modified example of Figure 6. [Figure 8] This is a schematic diagram showing a divided body portion according to the third embodiment. [Figure 9] This is a schematic diagram showing a modified example of the divided body section in Figure 8. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the attached drawings. In the drawings, the same reference numerals are used for identical components, and redundant descriptions are omitted. In the drawings, the size and proportions of each component are exaggerated to facilitate understanding of the embodiments and may differ from the actual size and proportions.

[0010] (First Embodiment) Figure 1 is a schematic diagram showing an airless tire according to the first embodiment. Figure 2 is a schematic diagram showing the spokes 22, spoke inner ring 23, intermediate ring 24, spoke outer ring 25, etc. that constitute the airless tire. Figure 3 is a schematic diagram showing the dashed line portion of Figure 2. Figures 4 and 5 are schematic diagrams showing radially adjacent segmented body portions 21.

[0011] The airless tire according to this embodiment can be used for passenger car tires. As shown in Figure 1 and other figures, the airless tire according to this embodiment has a wheel 10, a body portion 20, and a tread ring 30. These will be described below.

[0012] (wheel) The wheel 10 is fixed to the hub of a vehicle (not shown) (see part P in Figure 1 for the connection point with the vehicle). The wheel 10 is composed of, for example, a disc-shaped disc and a cylindrical rim, and is made of metal or other highly rigid material. In the front view of Figure 1, the wheel disc is shown as a circular member in the center of the airless tire, and this disc is fixed to the hub of the vehicle, thereby supporting the airless tire on the axle. The airless tire is positioned on the outer circumference of the wheel 10. The outer circumference of the wheel 10 is made of a curved surface, and is joined to the body portion 20 of the airless tire by adhesive or the like. However, the airless tire may be joined or connected to the wheel 10 by providing grooves on the outer surface of the wheel 10 or by providing a bolt fixing mechanism.

[0013] (Body part) The body portion 20 is the part between the wheel 10 and the tread ring 30, and comprises a radially divided body portion 21. For convenience, the divided body portion 21 is not shown in Figure 1. As shown in Figure 2, the divided body portion 21 has spokes 22, spoke inner rings 23, and intermediate rings 24 at its innermost circumference. The divided body portion 21 has spokes 22, intermediate rings 24, and spoke outer rings 25 at its outermost circumference. The divided body portion 21 has spokes 22 and intermediate rings 24 at parts other than the innermost and outermost circumferences. The body portion 20 is constructed by combining the divided body portions 21, and is made of an elastically deformable material. It holds the wheel load, mitigates the impact on the vehicle due to road surface irregularities, and generates a lateral load on the tire as the tire deforms due to the tire's sideways slip angle. For convenience, the boundaries of the spoke inner rings 23, spokes 22, intermediate rings 24, and spoke outer rings 25 are not shown in Figure 1. Further details are provided below.

[0014] The spokes 22 are arranged radially outward and periodically in the circumferential direction on the outer circumference of the wheel 10. The spokes 22 are made of an elastic material such as an elastic thermoplastic resin such as urethane or an elastic thermosetting resin, and are plate-shaped members having a width corresponding to the tire width. In this embodiment, the spokes 22 extend substantially radially (in a direction intersecting the circumferential direction) from the outer circumference of the wheel 10 toward the inner circumference of the tread ring 30, without passing through their centers, and are configured to be provided in multiples at equal intervals, spaced apart from each other along the circumferential direction of the tire. The multiple spokes 22 are provided axially symmetric with respect to the central axis of the tire. The number of spokes 22 provided on one airless tire is not particularly limited and can be set appropriately according to the tire's contact length, the load capacity of the spokes 22, vibration resistance, and other tire requirements.

[0015] As shown in FIG. 3, one spoke 22 forms at least one of an outer bending portion 26 (corresponding to a coupling portion and a bending portion) and an inner bending portion 27 (corresponding to a connecting portion and a bending portion) that bend in a direction connecting both ends between the wheel side end and the tread side end. The spoke 22 is formed in a zigzag shape when viewed in the tire rotation axis direction as shown in FIG. 3. In the present embodiment, as shown in FIG. 3, four outer bending portions 26 and five inner bending portions 27 are formed from the wheel side end toward the tread side end. The spoke 22 and the intermediate ring 24 are configured to intersect at the outer bending portion 26 or the inner bending portion 27. The spokes 22 are formed to face the same direction when viewed in the same divided body portion 21. The spokes 22 are formed to face different directions when viewed in adjacent divided body portions 21.

[0016] The spoke inner peripheral ring 23 is provided adjacent to the radially outer side of the wheel 10. The spoke outer peripheral ring 25 is provided adjacent to the radially inner side of the tread ring 30. The spoke 22, the intermediate ring 24, the spoke inner peripheral ring 23, and the spoke outer peripheral ring 25 can be formed by bonding the same material or different materials. In particular, if they are the same material, their connecting portions (interfaces) can be made stronger than in the case of different materials. At that time, by using a material such as urethane resin (TPU), elastic deformation is possible, and a material with a low tanδ characteristic of the material can be used, and vibration reduction and rolling resistance reduction by the tire can be realized. The spoke outer peripheral ring 25 intersects the spoke 22 at the inner bending portion 27.

[0017] The intermediate ring 24 is arranged in the circumferential direction and is configured to connect the spokes 22 that are circumferentially adjacent between the wheel 10 and the tread ring 30. The intermediate ring 24 is made of an elastic material such as a thermoplastic resin having elasticity or a thermosetting resin having elasticity, similar to the spokes 22. The intermediate ring 24 has a cylindrical shape with a tire width that is concentric with the wheel 10 and the tread ring 30. The number of intermediate rings provided in one airless tire is not particularly limited, but by making the number of intermediate rings an even number such as two or four, the balance of the forces in the circumferential direction of the tire is maintained. Therefore, the axial forces (compressive force and tensile force) acting on the intermediate ring throughout one circumference of the tire become continuous, and the load acting on the outer bent portion 26 or the inner bent portion 27 of the spoke 22 can be dispersed over the entire tire. As a result, there is an effect of reducing the rolling coefficient. The intermediate ring 24 is configured to be divided approximately in half in the radial direction at the adjacent divided body portions 21 in the present embodiment.

[0018] If the bending degree of the outer bent portion 26 or the inner bent portion 27 is extremely small, the spoke 22 will undergo buckling deformation between the outer bent portion 26 or the inner bent portion 27 and will not deform at the outer bent portion 26 or the inner bent portion 27, so the amount of deformation in the circumferential direction of the tire cannot be restricted. Therefore, although the inferior angle of the outer bent portion 26 or the inner bent portion 27 shown in FIG. 3 is not particularly limited, it is desirable to set it to less than 120°.

[0019] The body portion 20 is formed from a plurality of divided body portions 21 that are divided in the radial direction, and is configured to provide a connecting portion (inner bent portion 27) in the vicinity of the connecting portion (outer bent portion 26) of the spoke 22 and the intermediate ring 24. Thereby, it becomes possible to configure the cylindrical body portion 20 from the divided body portions 21 divided in the radial direction, and the resin material of the body portion 20 to be molded at one time can be reduced. As a result, it becomes possible to mold the body portion 20 with a small molding machine. Also, by configuring to have a connecting portion at the outer bent portion 26 of the spoke 22 or a connecting portion at the inner bent portion 27, buckling of the intermediate ring 24 can be prevented or suppressed.

[0020] In this embodiment, the joint is formed by press-fitting radially adjacent segmented body parts 21 (see Figures 4 and 5). That is, in this embodiment, the adjacent segmented body parts 21 are configured so that their circumferential position does not shift due to the press-fitting. In addition, in this embodiment, the adjacent segmented body parts 21 are joined not only by press-fitting but also by a urethane-based adhesive, but the use of adhesive is not required.

[0021] Furthermore, each spoke 22 forms at least one of an outer bend 26 and an inner bend 27 in adjacent segmented body sections 21 in the radial direction, and the outer bend 26 or inner bend 27 of adjacent spokes 22 in the circumferential direction are bent in the same direction with respect to the circumferential direction. The intermediate ring 24 is configured to connect (intersect) with the spokes 22 at the outer bend 26 or inner bend 27. This configuration allows the intermediate ring 24 to transmit the radial deformation of the tire due to the wheel load to the entire tire, thereby suppressing localized tire loads.

[0022] Furthermore, the intermediate ring 24 is divided radially, and the body sections 20 are connected radially by the intermediate ring 24. By dividing the intermediate ring 24 radially in this way and using adhesive, adjacent body sections 20 can be joined using the intermediate ring 24. This increases the connection strength of the body sections 20.

[0023] Furthermore, if the outer diameter of the divided body portion 21 provided on the inner circumference side is Ri and the inner diameter of the divided body portion 21 provided on the outer circumference side is Ro, then Ri is set to be larger than Ro. If Ri is larger than Ro, then when joining the divided body portions 21, it is necessary to either reduce the outer diameter of the divided body portion 21 on the inner circumference side or increase the inner diameter of the divided body portion 21 on the outer circumference side. By combining the divided body portions 21 in this way, the divided body portion 21 on the inner circumference side pushes against the divided body portion 21 on the outer circumference side, and the divided body portion 21 on the outer circumference side pushes against the divided body portion 21 on the inner circumference side. This increases the joint strength of the body portion 20.

[0024] Furthermore, the segmented body portion 21 provided on the inner circumference can be configured such that the material has a higher Young's modulus than the segmented body portion provided on the outer circumference. By configuring the outer circumference to be made of a softer material in this way, it becomes easier to absorb road surface irregularities, and the ride comfort of a vehicle using the airless tire according to this embodiment can be improved.

[0025] (Treadring) The tread ring 30 is formed in a cylindrical shape with the width of the tire and is located on the outermost circumference of the airless tire. The tread ring 30 can be made of a composite material in which an elastic material such as natural rubber or synthetic rubber is reinforced with metal or resin tire cords. A tread pattern is formed on the outer surface of the tread ring 30, similar to that of a conventional pneumatic tire, and it becomes the contact surface with the road surface.

[0026] When mounted on a vehicle, the wheel load held by the tire is supported by the elastic deformation of the body portion 20 and the tread ring 30. The load supported by the body portion 20 is mainly due to the deformation of the spokes 22, while the intermediate ring 24 suppresses the deformation of circumferentially adjacent spokes 22, distributing the load across the entire tire. The tread ring 30 should not have excessively high circumferential rigidity (not deforming even when a load is applied in the circumferential direction) in order to hold the wheel load in an airless tire, nor should it have excessively high radial rigidity (not deforming even when a load is applied in the radial direction) in order to mitigate road surface irregularities and ensure contact with the ground.

[0027] When the tread ring 30 is constructed from a single material, increasing circumferential rigidity requires using a harder material or increasing its thickness, which also increases radial rigidity. To avoid this, it is preferable to adopt a composite structure in which reinforcing fibers such as metal or capillaries are embedded in the rubber or resin tread.

[0028] (Second Embodiment) Figure 6 is a schematic diagram showing the segmented body portion 21a constituting the airless tire according to the second embodiment, and Figure 7 is a schematic diagram showing the segmented body portion 21b according to a modified example of Figure 6. In the first embodiment, the segmented body portion 21 was integrally constructed by press-fitting, but it can be constructed as follows.

[0029] As shown in Figure 6, the divided body portion 21a can be connected to adjacent divided body portions 21a by providing a concave or convex shape on the inner bent portion 27a on the outer or inner circumference side of the spoke 22 that can engage with each other.

[0030] As shown in Figure 7, the divided body portion 21b can be connected to adjacent divided body portions 21b by providing a concave or convex shape on the outer bend portion 26b on the outer or inner circumference side of the spoke 22 that can engage with each other.

[0031] By configuring it in this way, the adjacent divided body parts 21a and 21b can be more accurately aligned and integrated into a single unit.

[0032] Furthermore, the intermediate ring 24a can be provided so as to pass only through the inner circumference of the intermediate divided body portion 21a in the radial direction, as shown in Figure 6, and the intermediate ring 24b can be provided so as to pass only through the outer circumference of the intermediate divided body portion 21b, as shown in Figure 7. Also, the wheel 10, spoke inner circumference ring 23, spoke outer circumference ring 25, and tread ring 30 are the same as in the first embodiment, so their description is omitted.

[0033] (Third embodiment) Figure 8 is a schematic diagram showing the divided body portion 21c according to the third embodiment, and Figure 9 is a schematic diagram showing the divided body portion 21d, which is a variation of Figure 8. In the second embodiment, the intermediate rings 24a and 24b in the radially intermediate divided body portions 21a and 21b are provided to pass only through either the inner or outer circumference of the spoke 22. However, the intermediate ring 24 can be provided so as in the first embodiment, with the shape of the intermediate ring divided at the adjacent divided body portion 21c or divided body portion 21d. The uneven shape of the inner bent portion 27a can be configured in the same way as in Figure 6, as shown in Figure 8. The uneven shape of the outer bent portion 26b can be configured in the same way as in Figure 7, as shown in Figure 9. The wheel 10, spoke inner circumference ring 23, spoke outer circumference ring 25, and tread ring 30 are the same as in the first embodiment, so their description is omitted.

[0034] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. In the first embodiment, the spoke inner ring 23 was described as being joined to the body portion 20 by adhesive or the like. However, the invention is not limited to this, and the outermost circumference of the wheel and the inner circumference of the spoke inner ring 23 may be overlapped, holes may be provided in both, and the two may be joined together with bolts and nuts or the like. [Explanation of Symbols]

[0035] 10 wheels, 20 Body section, 21, 21a, 21b, 21c, 21d Divided body section, 22 spokes, 24 intermediate rings, 26, 26b Outer bending part (joint part, bending part), 27, 27a Inner bending part (connection part, bending part), 30 tread rings.

Claims

1. Wheels for connecting to the vehicle, Multiple spokes, which are elastic members, are periodically arranged in the circumferential direction on the outer circumference of the wheel. It has an intermediate ring which is an elastic member, which is arranged in the circumferential direction and connects adjacent spokes in the circumferential direction, and a body portion which consists of the spokes and the intermediate ring, In an airless tire comprising a tread ring, which is an elastic support member, positioned on the outermost circumference of the spokes, The body portion is formed from a plurality of radially divided body portions, and the airless tire has a connecting portion near the joint between the spoke and the intermediate ring.

2. In the radially adjacent divided body sections, the spokes have bent portions formed therein. The bent portions of the spokes adjacent to each other in the circumferential direction are bent in the same direction with respect to the circumferential direction. The airless tire according to claim 1, wherein the intermediate ring is connected to the spokes at the bent portion.

3. The airless tire according to claim 1 or 2, wherein the intermediate ring is divided radially in adjacent divided body portions, and the divided body portions are connected radially by the intermediate ring.

4. The airless tire according to claim 3, wherein the outer diameter of the divided body portion provided on the inner circumference is Ri, and the inner diameter of the divided body portion provided on the outer circumference is Ro, and Ri is smaller than Ro.

5. The airless tire according to any one of claims 1 to 4, wherein the divided body portion provided on the inner circumference side has a higher Young's modulus of material than the divided body portion provided on the outer circumference side.

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