Tire

Abstract

To provide a nonwoven product from which a tread component having improved traction performance can be made, and a tire.SOLUTION: A nonwoven product comprises a plurality of metal fibers having a cross section orthogonal to the longitudinal direction with a convex polygonal contour.SELECTED DRAWING: Figure 13B

Description

Technical Field

[0001] The present invention relates to a nonwoven body and a tire.

Background Art

[0002] Conventionally, tires configured using coil springs have been known. For example, Patent Document 1 discloses a tire in which each of a plurality of coil springs is combined with other coil springs and fixed to an annular rim, thereby forming a toroidal shape as a whole.

[0003] Further, Patent Document 2 discloses a tire including a skeleton portion and a tread member. The skeleton portion of Patent Document 2 includes a rim member, a plurality of main body springs, and a plurality of connecting springs.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The tire disclosed in Patent Document 1 has a wheel composed of a spring such as a coil spring, and due to the presence of a large number of gaps between the springs, appropriate running may not be possible depending on the running environment. For example, when running on sandy ground or the like with the tire disclosed in Patent Document 1, the tire may sink into the ground due to sand entering the gaps of the coil spring. Further, sand enters from the gaps of the coil spring toward the rotation center side of the wheel, and when, for example, a drive mechanism or the like exists on the rotation center side of the wheel, it may cause an abnormality in the drive mechanism. Therefore, with the tire disclosed in Patent Document 1, the running performance such as the expected driving force may decrease.

[0006] On the other hand, the tire disclosed in Patent Document 2 includes a tread member disposed on the outer periphery of a skeleton portion configured using a spring. Therefore, according to the tire disclosed in Patent Document 2, the above-described decrease in running performance can be suppressed.

[0007] However, the tire disclosed in Patent Document 2 has room for further improvement from the viewpoint of improving traction performance.

[0008] An object of the present invention is to provide a nonwoven fabric and a tire that can easily realize a tread member capable of improving traction performance.

Means for Solving the Problems

[0009] The nonwoven fabric as a first aspect of the present invention includes a plurality of metal fibers having a convex polygonal outer shape in a cross section orthogonal to the longitudinal direction. With this configuration, it becomes easy to realize a tread member capable of improving traction performance.

[0010] As one embodiment of the present invention, the outer shape of the metal fiber in the cross section orthogonal to the longitudinal direction is rectangular. With this configuration, it becomes easy to realize a tread member capable of improving traction performance.

[0011] As one embodiment of the present invention, the metal fiber is made of austenitic stainless steel or aluminum alloy. With this configuration, a tread member with ensured durability in an extremely low temperature environment can be realized.

[0012] The nonwoven fabric as one embodiment of the present invention is composed only of a plurality of the metal fibers. With this configuration, it becomes easier to realize a tread member capable of improving traction performance.

[0013] As one embodiment of the present invention, a plurality of the metal fibers are mechanically entangled and integrated. With this configuration, it is possible to realize durability that is not easily broken even in an environment with large temperature changes or an environment with a large amount of cosmic ray exposure such as the lunar surface.

[0014] The tire as the second aspect of the present invention includes a skeleton portion composed of a rim member, a plurality of main body springs locked to the rim member, and a plurality of connecting springs combined with the main body springs, and at least a tread member disposed on the outer periphery of the skeleton portion, and the tread member includes the nonwoven fabric. With this configuration, it becomes easier to realize a tread member capable of improving traction performance.

[0015] As one embodiment of the present invention, the nonwoven fabric is a sheet-shaped nonwoven fabric, and the nonwoven fabric is disposed on the outer periphery of the skeleton portion such that at least a part of it is embedded in a groove partitioned by the main body spring and the connecting spring in a rounded rod shape. With this configuration, a rod-shaped nonwoven fabric of the tread member can be easily realized.

[0016] As one embodiment of the present invention, the nonwoven fabric is rolled up so that a plurality of layers are laminated in the radial direction. With this configuration, it is possible to suppress a decrease in the performance of the tread member due to wear, chipping, etc., and extend the travelable distance.

Advantages of the Invention

[0017] According to the present invention, it is possible to provide a non-woven fabric and a tire that can realize a tread member capable of improving traction performance.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

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Figure 8

Figure 9A

Figure 9B

Figure 10

Figure 11

Figure 12

Figure 13A

Figure 13B

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Figure 18A

Figure 18B

Figure 19A

Figure 19B

Figure 20

Figure 21

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Figure 24

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the nonwoven fabric and the tire according to the present invention will be exemplarily described with reference to the drawings. The same reference numerals are given to the common configurations in each figure. In this specification, the tire width direction refers to the direction parallel to the rotation axis of the tire. The tire diameter direction refers to the direction orthogonal to the rotation axis of the tire and the radial direction centered on the rotation axis. The tire circumferential direction refers to the direction in which the tire rotates around the rotation axis of the tire.

[0020] FIG. 1 is an external perspective view of a tire 1 according to an embodiment of the present invention. The tire 1 according to this embodiment includes a skeleton portion 2 that defines the structure of the tire 1, and a tread member 300 attached to the skeleton portion 2.

[0021] <Skeleton portion 2> FIG. 2 is an external perspective view of the skeleton portion 2 of the tire 1. As shown in FIG. 2, the skeleton portion 2 of the tire 1 in this embodiment includes a wheel portion 10 as a rim member, and a ground deformation portion 20 that can be deformed when in contact with the ground.

[0022] FIG. 3 is an external perspective view of the wheel portion 10 of the skeleton portion 2 of the tire 1. The wheel portion 10 includes a plurality of rim portions. As shown in FIGS. 2 and 3, the wheel portion 10 in this embodiment includes two rim portions. More specifically, the wheel portion 10 in this embodiment includes a first rim portion 101 and a second rim portion 102. Further, the wheel portion 10 in this embodiment further includes a plurality of connecting portions 103 that connect the first rim portion 101 and the second rim portion 102. The number of rim portions included in the wheel portion 10 is not particularly limited. The wheel portion 10 may include, for example, three or more rim portions. The wheel portion having three rim portions and the wheel portion having four rim portions will be described later (see FIGS. 22 to 24).

[0023] The first rim portion 101 and the second rim portion 102 are made of metal or resin. The first rim portion 101 and the second rim portion 102 are each formed in an annular shape. The first rim portion 101 and the second rim portion 102 are arranged at different positions in the tire width direction A such that their central axes are the same axis. In the present embodiment, the first rim portion 101 and the second rim portion 102 are configured to have the same size and shape. However, as long as the functions of the tire 1 can be exhibited, the first rim portion 101 and the second rim portion 102 may be configured to have different sizes or shapes. The outer diameters of the first rim portion 101 and the second rim portion 102 may be appropriately determined according to the required size of the tire 1.

[0024] The connecting portion 103 connects the first rim portion 101 and the second rim portion 102. The connecting portion 103 is made of metal or resin. As shown in FIG. 3, the wheel portion 10 of the present embodiment includes six connecting portions 103, but the number of connecting portions 103 included in the wheel portion 10 is not limited to this. The plurality of connecting portions 103 are respectively attached to one surface side of the annular first rim portion 101 and one surface side of the annular second rim portion 102. Thereby, the connecting portion 103 integrates the first rim portion 101 and the second rim portion 102. Hereinafter, in this specification, with respect to the wheel portion 10, the side to which the connecting portion 103 is attached with respect to the first rim portion 101 and the second rim portion 102 is referred to as the "inner side in the tire width direction A", and the side to which the connecting portion 103 is not attached is referred to as the "outer side in the tire width direction A".

[0025] In the present embodiment, the first rim portion 101 and the second rim portion 102 include fitting receiving portions 105 (see FIG. 6) on the inner surface in the tire width direction A, into which the main body spring 201 of the ground deformation portion 20 can be fitted. Details of the fitting receiving portion and details of the fitting mode will be described later. In this specification, "fitting" means being fitted together, and "locking" broadly means being fastened, including the mode by fitting.

[0026] As shown in FIG. 3, the wheel part 10 as the rim member of the present embodiment further includes a support member 104 that maintains the fitting state of the ground deformation part 20 fitted to the fitting receiving part 105 (see FIG. 6). The support member 104 of the present embodiment is attached to the first rim part 101 and the second rim part 102. The support member 104 may be fixed inside the first rim part 101 and the second rim part 102 in the tire width direction A using, for example, bolts.

[0027] The ground deformation part 20 of the present embodiment is configured to be elastically deformable in the tire diameter direction B. As shown in FIG. 2, the ground deformation part 20 of the present embodiment includes a main body spring 201 and a connecting spring 211. The main body spring 201 and the connecting spring 211 are made of metal.

[0028] FIG. 4 is a schematic view showing an example of the main body spring 201 constituting the ground deformation part 20 shown in FIG. 2. The main body spring 201 connects between a plurality of rim parts. In the present embodiment, the main body spring 201 connects between the first rim part 101 and the second rim part 102. FIG. 22 is a view showing the skeleton part 2 including three rim parts 501 to 503. As shown in FIG. 22, when the wheel part 10 as the rim member of the skeleton part 2 has three rim parts 501 to 503, the main body spring 201 connects all pairs of two adjacent rim parts among the three rim parts 501 to 503 in the same manner as connecting the above-described first rim part 101 and second rim part 102. FIG. 24 is a view showing the skeleton part 2 including four rim parts. Although not shown in detail, also in the example shown in FIG. 24, the same main body spring 201 as in FIG. 22 connects all pairs of two adjacent rim parts among the four rim parts. However, in the skeleton part 2 including three or more rim parts, it may be configured to connect at least one pair of any two rim parts.

[0029] As shown in FIG. 4, the main body spring 201 includes an elastic deformation portion 202 and a locking portion 203. In the present embodiment, the elastic deformation portion 202 is configured by a coil spring. Here, a coil spring is a spring that elastically deforms according to a load and is wound in a coil shape (helical shape) around a predetermined axis. The elastic deformation portion 202 can use an elastic deformation portion 202 having an appropriate material and elasticity according to the size and weight of the target tire 1 and the properties of the required ground contact deformation portion 20 and the like.

[0030] The locking portion 203 is provided at both ends of the elastic deformation portion 202. The locking portion 203 locks the main body spring 201 to the wheel portion 10 as a rim member. The locking portion 203 has a shape different from that of the elastic deformation portion 202. That is, in the present embodiment, the locking portion 203 has a shape different from the coil shape.

[0031] In the present embodiment, the locking portion 203 is configured by a member integral with the elastic deformation portion 202. As shown in FIG. 4, the locking portion 203 of the present embodiment is configured by an extended portion which is a portion where the material constituting the elastic deformation portion 202 extends from both ends of the elastic deformation portion 202.

[0032] As shown in FIG. 4, the locking portion 203 of the present embodiment includes a straight portion 203a that is continuous with both ends of the elastic deformation portion 202 and extends linearly. Further, as shown in FIG. 4, the locking portion 203 of the present embodiment includes a bent portion 203b that is continuous with the tip side opposite to the base end side continuous with the elastic deformation portion 202 of the straight portion 203a and is bent with respect to the straight portion 203a. In the present embodiment, in a side view of the main body spring 201 (see FIG. 4), the bent portion 203b is bent so as to be orthogonal to the straight portion 203a. In other words, the bent portion 203b of the present embodiment is bent so as to be orthogonal to the straight portion 203a within a plane including the axis of the main body spring 201.

[0033] Here, with reference to FIGS. 5 to 7, the details of the mode of engagement of the main body spring 201 with the wheel portion 10 in the present embodiment will be described. The main body spring 201 is engaged with the wheel portion 10 as a rim member by fitting one of the locking portions 203 provided at both ends to the first rim portion 101 and the other locking portion 203 to the second rim portion 102. Here, an example in which the main body spring 201 is engaged with the wheel portion 10 with one of the locking portions 203 fitted to the first rim portion 101 will be described. However, the other locking portion 203 is engaged with the wheel portion 10 in the same manner with the other locking portion 203 fitted to the second rim portion 102.

[0034] FIG. 5 is a schematic view showing an example of the mode of engagement of the main body spring 201 with the wheel portion 10, and is a schematic view of the state in which the main body spring 201 is engaged with the wheel portion 10 as viewed from the inside in the tire width direction A of the first rim portion 101. Only a part of the portion where one of the locking portions 203 of the main body spring 201 is locked is shown in FIG. 5. Actually, as shown in FIG. 5, one of the locking portions 203 of the main body spring 201 is locked over the entire circumference of the first rim portion 101.

[0035] FIG. 6 is a cross-sectional view taken along the line I-I of FIG. 5. Specifically, it is a cross-sectional view of a portion including the fitting receiving portion 105 of the first rim portion 101. As shown in FIG. 6, the main body spring 201 of the present embodiment is engaged with the wheel portion 10 with the locking portion 203 fitted to the fitting receiving portion 105 provided on the inner surface in the tire width direction A of the first rim portion 101. In the present embodiment, the fitting receiving portion 105 is configured as a hole into which the bent portion 203b of the locking portion 203 can be inserted. More specifically, the fitting receiving portion 105 of the present embodiment is configured as a bottomed hole. The length in the extending direction of the hole of the fitting receiving portion 105 (the depth of the hole) is preferably longer than the length of the bent portion 203b. Thereby, the entire bent portion 203b can be inserted into the fitting receiving portion 105, and the fitting state is likely to be stabilized. However, the fitting receiving portion 105 may be configured as a through hole which is a non-bottomed hole.

[0036] The cross-sectional shape of the hole of the fitting receiving portion 105 is not limited as long as the bent portion 203b can enter, and may be, for example, an oval shape, an elliptical shape, a rectangular shape, a polygonal shape, or the like. In order for the elastic deformation portion 202 to be more reliably locked, it is preferable that the shape and size of the cross-section of the hole are substantially the same as the shape and size of the cross-section of the bent portion 203b.

[0037] As shown in FIG. 6, in a state where the bent portion 203b of the main body spring 201 is inserted into the fitting receiving portion 105, the elastic deformation portion 202 is arranged so as to be located outside the tire diameter direction B of the annular first rim portion 101 (the upper side in FIGS. 6 and 7) except for at least a part thereof. In this state, the support member 104 is attached to the first rim portion 101 on the inner side (the left side in FIGS. 6 and 7) in the tire width direction A of the first rim portion 101. As shown in FIG. 6, the support member 104 is attached at a position that suppresses the bent portion 203b inserted into the hole of the fitting receiving portion 105, that is, at a position where the bent portion 203b cannot come out of the hole of the fitting receiving portion 105. Preferably, the support member 104 is attached at a position that closes the hole of the fitting receiving portion 105 in a state where the main body spring 201 is not inserted. Further, as shown in FIG. 6, the support member 104 sandwiches the straight portion 203a of the locking portion 203 between the inner surface of the first rim portion 101 in the tire width direction A. In other words, the support member 104 is fixed to the first rim portion 101 so as to sandwich the straight portion 203a of the locking portion 203 between the inner surface of the first rim portion 101 in the tire width direction A. Thus, in the main body spring 201 of the present embodiment, in a state where the bent portion 203b of the locking portion 203 is fitted to the fitting receiving portion 105, the straight portion 203a and the bent portion 203b of the locking portion 203 are sandwiched between the inner surface of the first rim portion 101 in the tire width direction A and the support member 104, thereby being locked to the wheel portion 10.

[0038] The support member 104 of the present embodiment is attached to the first rim portion 101 using, for example, bolts 106. FIG. 7 is a cross-sectional view taken along line II-II of FIG. 5. More specifically, FIG. 7 is a cross-sectional view of a location including the bolts 106 that fix the support member 104 to the first rim portion 101. As shown in FIG. 7, the support member 104 is fixed to the first rim portion 101 by bolts 106. As shown in FIG. 5, the support member 104 may be fixed to the first rim portion 101 at a position between the two main body springs 201. That is, in the first rim portion 101, one bolt hole 107 for fixing the bolt 106 is formed between two adjacent fitting receiving portions 105 in the tire circumferential direction C of the annular first rim portion 101. Thereby, the support member 104 can be fixed to the first rim portion 101 without interfering with the locking position of the main body spring 201.

[0039] As shown in FIGS. 5 to 7, the bolt 106 may be provided such that the tip of the thread of the bolt 106 protrudes inward in the tire width direction A from the inner surface of the support member 104 in the tire width direction A. The tip of the bolt 106 that protrudes further inward in the tire width direction A than the inner surface of the support member 104 in the tire width direction A may be used to fix the fixing portion of the tread member 300 described later.

[0040] The support member 104 may be configured as a single annular member, or may be configured as a plurality of divided members that are annular as a whole. In that case, the plurality of support members 104 may be arranged such that two adjacent support members 104 in the tire circumferential direction C are in contact with or overlap at the ends in the tire circumferential direction C. Also, two adjacent support members 104 in the tire circumferential direction C may be arranged to be spaced apart at an appropriate interval in the tire circumferential direction C. When the support member 104 is configured as a plurality of divided members, each member may be, for example, fan-shaped.

[0041] A plurality of main body springs 201 are arranged at predetermined intervals in the tire circumferential direction C over the entire area in the tire circumferential direction C. One locking portion 203 of each of these plurality of main body springs 201 is locked to the wheel portion 10 by the above-described locking mode using the fitting receiving portion 105 of the first rim portion 101. Also, the other locking portion 203 of the main body spring 201 is locked to the wheel portion 10 in the same manner by the above-described locking mode using the fitting receiving portion 105 of the second rim portion 102. At this time, in the present embodiment, one locking portion 203 and the other locking portion 203 of one main body spring 201 may be fitted to the fitting receiving portions 105 of the first rim portion 101 and the second rim portion 102, which are located on one straight line substantially parallel to the tire width direction A. That is, in the present embodiment, the two locking portions 203 of one main body spring 201 may be fixed at the same position in the tire circumferential direction C with respect to the first rim portion 101 and the second rim portion 102. However, the two locking portions 203 of one main body spring 201 may be fixed at different positions in the tire circumferential direction C with respect to the first rim portion 101 and the second rim portion 102.

[0042] The quantity of the main body springs 201 fitted to the first rim portion 101 and the second rim portion 102 and the intervals in the tire circumferential direction C may be appropriately determined according to the size and weight of the tire 1, the nature of the required ground contact deformation portion 20, and the like. The quantity of the bolts 106 used for attaching the support members 104 to the first rim portion 101 and the second rim portion 102 and the intervals in the tire circumferential direction C may also be appropriately determined. For example, the bolts 106 do not necessarily have to be attached one by one between two adjacent fitting receiving portions 105 in the tire circumferential direction C as in the present embodiment.

[0043] In the skeleton portion 2 of the tire 1 according to the present embodiment, a plurality of main body springs 201 locked to the wheel portion 10 in this way are connected to the connecting spring 211, thereby forming the ground contact deformation portion 20. That is, in the present embodiment, the connecting spring 211 functions as a connecting member that connects adjacent main body springs 201. FIG. 8 is a schematic view showing an example of the connecting spring 211 that constitutes the ground contact deformation portion 20 of FIG. 2. In the present embodiment, as shown in FIG. 8, the connecting spring 211 includes an elastic deformation portion 212 and a restricting portion 213. The connecting spring 211 is locked to the wheel portion 10 and is disposed between two main body springs 201 adjacent in the tire circumferential direction C. Then, the connecting spring 211 is combined with these two main body springs 201 to be connected to the main body spring 201.

[0044] In the present embodiment, the elastic deformation portion 212 is constituted by a coil spring. The elastic deformation portion 212 can use an elastic deformation portion 212 having an appropriate material and elasticity according to the desired size and weight of the tire 1 and the properties of the required ground contact deformation portion 20. The diameter of the coil spring that constitutes the elastic deformation portion 212 is preferably closer to the diameter of the coil spring that constitutes the elastic deformation portion 202 of the main body spring 201. Here, the diameter of the coil spring is the diameter of the circumscribed circle when the coil spring is viewed from the axial direction, and the same applies hereinafter. The closer the diameter of the coil spring that constitutes the elastic deformation portion 212 is to the diameter of the coil spring that constitutes the elastic deformation portion 202 of the main body spring 201, the more evenly the force is likely to be applied when the coil spring that constitutes the elastic deformation portion 202 and the coil spring that constitutes the elastic deformation portion 212 are connected as described later to form the ground contact deformation portion 20. For example, the diameters of the coil spring that constitutes the elastic deformation portion 202 and the coil spring that constitutes the elastic deformation portion 212 can both be 15 mm to 25 mm, for example, 20 mm.

[0045] In this embodiment, the restricting portion 213 is provided at one end of the elastic deformation portion 212. In the elastic deformation portion 212, no other mechanism is configured at the other end where the restricting portion 213 is not provided. Therefore, the elastic deformation portion 212 has a shape that seems to be interrupted on the other end side. The restricting portion 213 restricts the displacement of the connecting spring 211 connected to the main body spring 201 with respect to the main body spring 201. The restricting portion 213 only needs to restrict the displacement of the connecting spring 211 with respect to the main body spring 201 in at least one direction. Thus, since the displacement of the connecting spring 211 with respect to the main body spring 201 is restricted by the restricting portion 213, when the connecting spring 211 is connected to the main body spring 201, as will be described with reference to FIGS. 9A and 9B described later, the connecting position of the connecting spring 211 is determined and fixed. That is, the connecting state of the connecting spring 211 with respect to the main body spring 201 is positioned and fixed. The restricting portion 213 has a shape different from that of the elastic deformation portion 212. That is, in this embodiment, the restricting portion 213 has a shape different from the coil shape.

[0046] In this embodiment, the restricting portion 213 is constituted by a member integral with the elastic deformation portion 212. As shown in FIG. 8, the restricting portion 213 of this embodiment is an extended portion constituted by a portion where the material constituting the elastic deformation portion 212 extends from one end of the elastic deformation portion 212. In the example shown in FIG. 8, the restricting portion 213 has an annular portion formed by bending the wire forming the elastic deformation portion 212 into an annular shape. The annular shape is formed such that the direction intersecting the central axis direction D parallel to the central axis O of the elastic deformation portion 212 is the central axis direction E. The annular portion of the restricting portion 213 may have any size capable of restricting the displacement of the connecting spring 211. For example, the annular portion of the restricting portion 213 may be configured such that the diameter is 0.5 to 1.0 times the diameter of the elastic deformation portion 212.

[0047] Here, the function of the restricting portion 213 will be described together with the method of connecting the connecting spring 211 to the main body spring 201. FIGS. 9A and 9B are schematic diagrams for explaining an example of the method of connecting the connecting spring 211 to the main body spring 201.

[0048] As shown in FIG. 9A, the connecting spring 211 connects the elastic deformation portion 212 thereof to the elastic deformation portion 202 of the main body spring 201 locked to the wheel portion 10 and engages with two adjacent main body springs 201, so that it is connected to these two main body springs 201. Specifically, the connecting spring 211 is connected to the main body spring 201 so as to regulate the relative displacement between two adjacent main body springs 201 in the tire circumferential direction C. At this time, the connecting spring 211 is inserted into the main body spring 201 so as to advance while rotating, starting from the other end side where the restricting portion 213 is not provided, and is gradually combined with two adjacent main body springs 201.

[0049] When the entire elastic deformation portion 212 of the connecting spring 211 is combined with the main body spring 201, eventually, as shown in FIG. 9B, the restricting portion 213 comes into contact with the main body spring 201. Due to its shape, the restricting portion 213 cannot be combined with the main body spring 201. Therefore, the connecting spring 211 does not move toward the insertion direction side beyond the position where the restricting portion 213 contacts the main body spring 201. In particular, after the ring-shaped portion of the restricting portion 213 contacts the main body spring 201, the connecting spring 211 does not advance (move toward the insertion direction side) even if it is tried to be advanced while rotating. In this way, the restricting portion 213 restricts the displacement of the connecting spring 211 with respect to the main body spring 201 in at least one direction. In this way, the restricting portion 213 positions and fixes the connection state of the connecting spring 211 with respect to the main body spring 201. Also, the connecting spring 211 connected to the main body spring 201 is less likely to come off from the main body spring 201.

[0050] Note that, it is preferable that at least one of the two ends of the connecting spring 211 is not fixed to the wheel portion 10. In the present embodiment, neither end of the connecting spring 211 is fixed to the wheel portion 10. That is, in the present embodiment, both ends of the connecting spring 211 are unfixed. However, only one end of the two ends of the connecting spring 211 may be fixed to the wheel portion 10. In this case, the other end of the two ends of the connecting spring 211, which is opposite to the end provided with the restricting portion 213, is fixed to the rim member.

[0051] In the present embodiment, all the main body springs 201 locked to the wheel portion 10 are connected by the connecting spring 211 to each of two adjacent main body springs 201. In the present embodiment, the skeleton portion 2 is configured in this way. That is, in the present embodiment, all the main body springs 201 of the grounding deformation portion 20 of the skeleton portion 2 are connected to two connecting springs 211, and all the connecting springs 211 of the grounding deformation portion 20 of the skeleton portion 2 are connected to two main body springs 201. In this way, by connecting the connecting spring 211 between two adjacent main body springs 201, even when a load is applied to the skeleton portion 2, the distance between the main body springs 201 does not spread too much, and it becomes easier to maintain the function as the tire 1.

[0052] Note that the connecting spring 211 that connects the two main body springs 201 may be inserted from the first rim portion 101 side toward the second rim portion 102 side or from the second rim portion 102 side toward the first rim portion 101 side in the tire width direction A. It is preferable that half of the plurality of connecting springs 211 provided in the frame portion 2 are inserted from the first rim portion 101 side toward the second rim portion 102 side in the tire width direction A, and the other half are inserted from the second rim portion 102 side toward the first rim portion 101 side in the tire width direction A. As a result, the restricting portions 213 of the connecting spring 211 are evenly arranged on both sides of the frame portion 2 in the tire width direction A, making it easier to balance the frame portion 2. Also, it is possible to prevent the restricting portions 213 from concentrating on only one side of the frame portion 2 in the tire width direction A. In particular, it is more preferable that the two connecting springs 211 adjacent in the tire circumferential direction C are inserted from different directions. This further facilitates the balancing of the frame portion 2.

[0053] Further, the frame portion 2 may further include a connecting member that connects the ring-shaped portions of the restricting portions 213 of the plurality of connecting springs 211. The connecting member may be constituted by, for example, a wire. For example, it is assumed that half of the plurality of connecting springs 211 are inserted from the first rim portion 101 side toward the second rim portion 102 side, and the other half are inserted from the second rim portion 102 side toward the first rim portion 101 side. In this case, the restricting portion 213 of the connecting spring 211 inserted from the first rim portion 101 side toward the second rim portion 102 side is located on the first rim portion 101 side in the tire width direction A, and the restricting portion 213 of the connecting spring 211 inserted from the second rim portion 102 side toward the first rim portion 101 side is located on the second rim portion 102 side in the tire width direction A. In this case, the frame portion 2 may have two wires, namely, a wire that connects the ring-shaped portions of the plurality of restricting portions 213 located on the first rim portion 101 side in the tire width direction A and a wire that connects the ring-shaped portions of the plurality of restricting portions 213 located on the second rim portion 102 side in the tire width direction A.

[0054] The wire connecting the annular portions of the plurality of restricting portions 213 located on the side of the first rim portion 101 is provided, for example, along the tire circumferential direction C so as to pass through all the central openings of the annular shape of the plurality of restricting portions 213 located on the side of the first rim portion 101. Similarly, the wire connecting the annular portions of the plurality of restricting portions 213 located on the side of the second rim portion 102 is provided, for example, along the tire circumferential direction C so as to pass through all the central openings of the annular shape of the plurality of restricting portions 213 located on the side of the second rim portion 102. By providing such a wire, the restricting portions 213 of the plurality of connecting springs 211 can be connected to each other. Therefore, the displacement of the relative positional relationship between the restricting portions 213 is restricted by the wire. As a result, the connecting spring 211 coupled to the main body spring 201 is less likely to come off from the main body spring 201.

[0055] However, the connecting member that connects the annular portions of the restricting portions 213 of the plurality of connecting springs 211 does not necessarily have to be configured to pass through the central openings of the annular shapes of the plurality of restricting portions 213 as described above, and the restricting portions 213 may be connected to each other in any form. In this case, for example, the connecting member may connect the annular portions of the plurality of restricting portions 213 by being fixed to each of the annular portions of the plurality of restricting portions 213 to be connected. At least, since the wire for connecting the restricting portions 213 of the plurality of connecting springs 211 is provided, the displacement of the relative positional relationship between the connecting springs 211 connected by the wire is restricted.

[0056] In addition, in the above embodiment, although it has been described that the annular portion of the restricting portion 213 has a central axis direction E intersecting the central axis direction D parallel to the central axis O of the elastic deformation portion 212, the shape of the restricting portion 213 is not limited to this. The restricting portion 213 may have any configuration capable of restricting the displacement of the connecting spring 211 with respect to the main body spring 201 in at least one direction.

[0057] Also, in the present embodiment, the restricting portion 213 is configured by a member integral with the elastic deformation portion 212, but the restricting portion 213 may not be configured by a member integral with the elastic deformation portion 212. For example, as schematically shown in FIG. 10, the displacement of the connecting spring 211 with respect to the main body spring 201 may be restricted by a restricting portion 213 configured by an independent member different from the connecting spring 211. In the example shown in FIG. 10, the restricting portion 213 is configured as an independent member separate from the connecting spring 211 that restricts the displacement of the contact portion between the main body spring 201 and the connecting spring 211 combined with each other.

[0058] The length of the connecting spring 211 may be appropriately determined according to the intended size and weight of the tire 1, the properties of the required ground contact deformation portion 20, and the like. It is preferable that the length of the elastic deformation portion 212 of the connecting spring 211 is shorter than the length of the elastic deformation portion 202 of the main body spring 201. The connecting spring 211 preferably has a length such that the elastic deformation portion 212 extends over the entire tire width direction A. Thereby, at least the region that contacts the ground in the tire width direction A of the elastic deformation portion 202 of the main body spring 201 is connected to the elastic deformation portion 212 of the connecting spring 211.

[0059] <Tread member 300> As shown in FIG. 1, the tire 1 includes a tread member 300 disposed on the outer periphery of the above-described skeleton portion 2.

[0060] FIGS. 11 and 12 are views showing a state in which the tread member 300 is attached to a part of the skeleton portion 2. More specifically, FIG. 11 is a view of the skeleton portion 2 with the tread member 300 partially attached, as seen from the outside in the tire diameter direction B. FIG. 12 is an enlarged view showing a part of the skeleton portion 2 with the tread member 300 partially attached.

[0061] As shown in FIGS. 1, 11, and 12, the tread member 300 is mounted at least on the grounding region of the grounding deformation portion 20 of the skeleton portion 2, which includes the main body spring 201 and the connecting spring 211. More specifically, the tread member 300 is mounted on the skeleton portion 2 so as to cover at least a part of the outer side in the tire radial direction B of the grounding deformation portion 20 of the skeleton portion 2. Further, as in the present embodiment, it is preferable that the tread member 300 is mounted on the skeleton portion 2 so as to cover the outer side in the tire radial direction B of the grounding deformation portion 20 of the skeleton portion 2 over the entire region in the tire width direction A of the grounding deformation portion 20. Also, as in the present embodiment, it is preferable that the tread member 300 is mounted on the skeleton portion 2 so as to cover the outer side in the tire radial direction B of the grounding deformation portion 20 of the skeleton portion 2 over the entire region in the tire circumferential direction C. In particular, as in the present embodiment, the tread member 300 is positioned between the first rim portion 101 and the second rim portion 102 so that the main body spring 201 and the connecting spring 211 are not exposed to the outside, and the entire outer sides in the tire width direction A of the main body spring 201 and the connecting spring 211, and the entire outer side in the tire radial direction B are mounted so as to cover the entire region in the tire circumferential direction C.

[0062] As shown in FIGS. 11 and 12, the outer surface of the skeleton portion 2 on the outer side in the tire radial direction B is constituted by the main body spring 201 and the connecting spring 211 combined with each other. A groove 230 is formed on the outer surface of the skeleton portion 2 on the outer side in the tire radial direction B by the main body spring 201 and the connecting spring 211 combined with each other.

[0063] As described above, the positions in the tire circumferential direction C of both end portions of the main body spring 201 of the present embodiment that are locked to the wheel portion 10 are the same position. That is, the plurality of main body springs 201 that constitute the grounding deformation portion 20 of the present embodiment have a radial structure that extends radially from the rotation axis of the tire 1 in a side view of the tire along the rotation axis. Therefore, the connecting spring 211 woven with the main body spring 201 also has a radial structure that extends radially from the rotation axis of the tire 1 in a side view of the tire. Thus, when the main body spring 201 and the connecting spring 211 have a radial structure that extends radially in a side view of the tire, as shown in FIGS. 11 and 12, the groove 230 is formed to extend in a direction intersecting the tire width direction A and the tire circumferential direction C. Hereinafter, for convenience of explanation, the direction in which the groove 230 extends is referred to as the "extending direction F" (see FIG. 11). In the present embodiment, the pitch of the coil spring of the elastic deformation portion 202 of the main body spring 201 and the pitch of the coil spring of the elastic deformation portion 212 of the connecting spring 211 are substantially equal.

[0064] As shown in FIGS. 11 and 12, in the present embodiment, the tread member 300 is mounted in a groove 230 formed by a main body spring 201 and a connecting spring 211. FIG. 13A is a schematic cross-sectional view showing a schematic of a cross-section orthogonal to the extending direction F of the groove 230 of the tread member 300 mounted in the groove 230. As shown in FIG. 13A, the tread member 300 is mounted such that at least a part thereof is embedded in the groove 230. By mounting the tread member 300 such that at least a part thereof is embedded in the groove 230, the tread member 300 is less likely to fall out of the groove 230. In the present embodiment, only a part of the tread member 300, that is, only the part on the inner side in the tire diameter direction B (the lower part in FIG. 13A) of the tread member 300 is mounted so as to be embedded in the groove 230, and the part on the outer side in the tire diameter direction B (the upper part in FIG. 13A) of the tread member 300 is exposed from the groove 230. In this case, vibrations during running can be suppressed. However, the tread member 300 may be mounted such that its entire body is embedded in the groove 230. In this case, the tread member 300 is less likely to fall out of the groove 230. In the present embodiment, as shown in FIG. 1, the tread member 300 is embedded in all the grooves 230 formed in the skeleton portion 2. The tread member 300 of the present embodiment is arranged so as to be in contact with the adjacent tread members 300 in the tire circumferential direction C. However, the tread member 300 does not necessarily have to be embedded in all the grooves 230. For example, the tread member 300 may be embedded only in a part of the grooves 230 formed in the skeleton portion 2.

[0065] In the present embodiment, it is preferable that the tread member 300 is detachably mounted on the skeleton portion 2. By detachably mounting the tread member 300 on the skeleton portion 2, when the tread member 300 is worn, etc., the tread member 300 can be removed from the skeleton portion 2 and replaced.

[0066] As shown in FIG. 13A, the tread member 300 includes a non-woven fabric 302. More specifically, the tread member 300 of the present embodiment shown in FIG. 13A is constituted by the non-woven fabric 302.

[0067] FIG. 13B is a diagram showing an outer shape of a cross section (hereinafter simply referred to as a "cross-sectional outer shape") orthogonal to the longitudinal direction of a plurality of metal fibers 302a constituting the nonwoven body 302. As shown in FIG. 13B, the nonwoven body 302 includes a plurality of metal fibers 302a having a rectangular cross-sectional outer shape. More specifically, the fibers constituting the nonwoven body 302 of the present embodiment are only a plurality of metal fibers 302a having a rectangular cross-sectional outer shape. Note that the "rectangle" means a quadrilateral (square or rectangle) in which all angles are right angles.

[0068] Although the cross-sectional outer shape of the metal fiber 302a in this embodiment is rectangular, the cross-sectional outer shape of the metal fiber 302a is not limited to a rectangular shape. The cross-sectional outer shape of the metal fiber 302a may be various convex polygonal shapes, including triangular, rhombic, and other parallelogram shapes, and regular pentagonal shapes. A "convex polygon" is a simple polygon without self-intersection, and a line segment connecting any two points inside or on the boundary of the polygon does not extend outside the polygon. As shown in FIG. 13B, by using such a metal fiber 302a to form the ground contact surface 300b (the upper surface in FIG. 13B) of the tread member 300, fine irregularities can be formed on the ground contact surface 300b of the tread member 300. FIGS. 14(a), 14(b), and 14(c) are conceptual diagrams showing a state where the ground contact surface 300b of the tread member 300 shown in FIG. 13B is in contact with a running road surface having fine irregularities formed thereon. FIGS. 14(a), 14(b), and 14(c) show a running road surface Y formed by filling angular particles X. Examples of the running road surface Y formed by filling angular particles X include the lunar surface covered with angular regolith having an average particle size of about 70 μm and the seabed surface covered with gravel. FIGS. 14(a), 14(b), and 14(c) differ only in that the sizes of the cross-sectional outer shapes of the metal fibers 302a constituting the ground contact surface 300b of the tread member 300 are different. As shown in FIGS. 14(a), 14(b), and 14(c), the fine irregularities formed on the ground contact surface 300b of the tread member 300 are easily engaged with the fine irregularities of the running road surface Y. Therefore, by configuring the ground contact surface 300b of the tread member 300 to have fine irregularities formed by the metal fibers 302a, high traction performance can be realized when running on the running road surface Y having fine irregularities formed thereon.

[0069] In the case of assuming a traveling road surface Y formed by filling angular particles X with an average particle diameter α, the length of each side of the cross-section of the metal fiber 302a having a square cross-sectional shape (hereinafter referred to as "the length of each cross-sectional side") β preferably satisfies the following (Equation 1). Note that FIG. 14(a) shows a state of "β = √2α". FIG. 14(b) shows a state of "β = √2α / 2". FIG. 14(c) shows a state of "β = √2α / 4". By setting the length of each cross-sectional side β of the metal fiber 302a to be √2α / 4 or more, it becomes easier to realize a metal fiber 302a having a strength that is difficult to be damaged or broken even during traveling on the traveling road surface Y. Also, by setting the length of each cross-sectional side β of the metal fiber 302a to be √2α or less, it becomes easier to realize the unevenness of the ground contact surface 300b that easily meshes with the unevenness of the traveling road surface Y.

[0070] √2α / 4 ≦ β ≦ √2α ········(Equation 1)

[0071] As an example, when the nonwoven fabric 302 of the present embodiment is used as the tread member 300 of a lunar vehicle, since the average particle diameter of the regolith is about 70 μm, based on the above (Equation 1), it is preferable that 24.7 μm ≦ β ≦ 98.9 μm for the length of each cross-sectional side β of the metal fiber 302a.

[0072] In the case of assuming a traveling road surface Y formed by filling angular particles X with an average particle diameter α, the fiber conversion diameter γ of the metal fiber 302a having a convex polygonal cross-sectional shape preferably satisfies the following (Equation 2). Note that the fiber conversion diameter γ means the diameter of a circle when the cross-sectional area of the metal fiber 302a having a convex polygonal cross-sectional shape is converted into a circular area. Note that FIG. 14(a) shows a state where the fiber conversion diameter γ of the metal fiber 302a is close to "2α". FIG. 14(b) shows a state where the fiber conversion diameter γ of the metal fiber 302a is close to "α". FIG. 14(c) shows a state where the fiber conversion diameter γ of the metal fiber 302a is close to "α / 2". By setting the fiber conversion diameter γ of the metal fiber 302a to be α / 2 or more, it becomes easier to realize a metal fiber 302a having a strength that is difficult to be damaged or broken even during traveling on the traveling road surface Y. Also, by setting the fiber conversion diameter γ of the metal fiber 302a to be 2α or less, it becomes easier to realize the unevenness of the ground contact surface 300b that easily meshes with the unevenness of the traveling road surface Y.

[0073] α / 2 ≤ γ ≤ 2α ········(Equation 2)

[0074] Incidentally, as an example, when the non-woven fabric 302 of the present embodiment is used as the tread member 300 of a lunar rover, since the average particle size of the regolith is about 70 μm, based on the above (Equation 2), the fiber-equivalent diameter γ of the metal fiber 302a is preferably 35 μm ≤ γ ≤ 140 μm.

[0075] In this way, by configuring the ground contact surface 300b of the tread member 300 with a plurality of metal fibers 302a having a convex polygonal cross-sectional outer shape, the traction performance during traveling on a traveling road surface with fine irregularities can be enhanced.

[0076] As described above, the tread member 300 of the present embodiment is composed of a non-woven fabric 302 including a plurality of metal fibers 302a having a rectangular cross-sectional outer shape. Therefore, by configuring the ground contact surface 300b of the tread member 300 with a portion including the metal fibers 302a having a rectangular cross-sectional outer shape, the above-described traction performance can be obtained. More specifically, as described above, the fibers constituting the non-woven fabric 302 of the present embodiment are only the metal fibers 302a having a rectangular cross-sectional outer shape. Therefore, any portion of the non-woven fabric 302 may be used to configure the ground contact surface 300b of the tread member 300.

[0077] Incidentally, the fibers constituting the non-woven fabric 302 may include fibers having a non-convex polygonal cross-sectional outer shape. However, among the total number of fibers constituting the non-woven fabric 302, the ratio of the number of metal fibers 302a having a convex polygonal cross-sectional outer shape is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and most preferably 100% as in the present embodiment.

[0078] The metal fiber 302a is preferably made of austenitic stainless steel or an aluminum alloy. Further, it is preferable that all the fibers constituting the nonwoven body 302 are made of metal regardless of the cross-sectional outer shape thereof, and it is particularly preferable that they are made of austenitic stainless steel or an aluminum alloy. By making all the fibers constituting the nonwoven body 302 made of austenitic stainless steel or an aluminum alloy, a structure that is difficult to break even in an extremely low temperature environment can be realized. That is, by using such a nonwoven body 302, a tread member 300 with ensured durability in an extremely low temperature environment can be realized. In particular, if the fibers constituting the nonwoven body 302 are made of an aluminum alloy, not only the above-mentioned durability can be ensured, but also weight reduction is easily achieved.

[0079] As shown in FIGS. 11 and 12, the tread member 300 of the present embodiment is configured in a rod shape so as to be embeddable along the groove 230. A through hole penetrating in the extending direction may be defined in the central portion of the rod-shaped tread member 300 of the present embodiment.

[0080] Furthermore, it is preferable that 50% or more of the total number of fibers constituting the nonwoven body 302 extend in a substantially equal direction. By doing so, it becomes easier to realize a ground contact surface 300b having substantially uniform irregularities formed by a plurality of metal fibers 302a (see FIGS. 14(a) to 14(c)). By doing so, more stable traction performance can be obtained. It is more preferable that 80% or more of the total number of fibers constituting the nonwoven body 302 extend in a substantially equal direction. By doing so, a ground contact surface 300b having more uniform irregularities can be realized. Hereinafter, for the sake of convenience of explanation, the above-mentioned "substantially equal direction" in which 50% or more of the total number of fibers constituting the nonwoven body 302 extend is referred to as the "main fiber direction".

[0081] Here, as described above, the tread member 300 of the present embodiment is configured in a rod shape. That is, the nonwoven fabric 302 constituting the tread member 300 of the present embodiment is configured in a rod shape. In the present embodiment, the above-described main fiber direction is a direction along the longitudinal direction of the entire rod-shaped nonwoven fabric 302. By doing so, by appropriately setting the cross-sectional outer shape and cross-sectional dimensions of the metal fibers 302a, it becomes easier to control the size of the recess formed between two adjacent metal fibers 302a to a desired size. Therefore, it becomes easier to realize irregularities of a size corresponding to the irregularities of the running road surface on the grounding surface 300b of the tread member 300.

[0082] As shown in FIG. 13A, the cross-sectional outer shape orthogonal to the longitudinal direction of the rod-shaped nonwoven fabric 302 constituting the tread member 300 of the present embodiment is an oval shape, but is not limited to this shape. The cross-sectional outer shape orthogonal to the longitudinal direction of the rod-shaped nonwoven fabric 302 may be, for example, a circular shape, a gourd shape (see FIGS. 19A and 19B), or the like.

[0083] Note that the tread member 300 is not limited to the example shown in FIG. 13A. FIG. 15 is a diagram showing a modified example of the tread member 300. The tread member 300 shown in FIG. 15 is also constituted by a nonwoven fabric 302, similar to the example shown in FIG. 13A. The nonwoven fabric 302 shown in FIG. 15 is also constituted by a plurality of metal fibers 302a having a rectangular cross-sectional outer shape. However, the nonwoven fabric 302 constituting the tread member 300 shown in FIG. 15 is not a mass of intertwined metal fibers 302a, but a sheet-shaped nonwoven fabric. As shown in FIG. 15, the sheet-shaped nonwoven fabric is in a rounded rod shape and at least a part of it is embedded in a groove 230 (see FIGS. 11 and 12) partitioned by a main spring 201 (see FIG. 9A, etc.) and a connecting spring 211 (see FIG. 9A, etc.). By adopting such a configuration, a rod-shaped nonwoven fabric 302 of the tread member 300 can be easily realized.

[0084] Further, as shown in FIG. 15, the sheet-like nonwoven fabric as the nonwoven body 302 is preferably rolled up such that a plurality of layers are laminated in the radial direction. By doing so, even if wear or chipping occurs in the outermost layer in the radial direction during running, another layer with the same configuration appears on the inner side in the radial direction, so that it is difficult for the performance of the tread member 300 to deteriorate. Therefore, it is possible to suppress a decrease in the performance of the tread member 300 due to wear, chipping, etc., and extend the travelable distance.

[0085] Furthermore, the nonwoven fabric constituting the nonwoven body 302 is preferably formed by a needle punching method. The needle punching method refers to a manufacturing method in which a plurality (for example, several thousand) of needles are simultaneously moved up and down and pierced into a web in which fibers are formed into a sheet shape, and the fibers are entangled with each other to form a nonwoven fabric. That is, it is preferable that the nonwoven fabric constituting the nonwoven body 302 has a structure in which the fibers are mechanically entangled with each other and integrated. By doing so, it is possible to realize a durable nonwoven body 302 that is difficult to break even in an environment with a large temperature change or an environment with a large amount of cosmic ray exposure such as the lunar surface. Note that it is preferable that the nonwoven fabric constituting the nonwoven body 302 is not bonded by an adhesive or welding.

[0086] Also, as described above, it is preferable that the main fiber direction of the fibers constituting the nonwoven body 302 is a direction along the longitudinal direction of the entire rod-shaped nonwoven body 302. Therefore, when the rod-shaped nonwoven body 302 is formed by rolling up the sheet-like nonwoven fabric, as shown in FIG. 16, the winding direction (rolled-up direction) of the sheet-like nonwoven fabric is preferably a direction orthogonal to the main fiber direction.

[0087] FIG. 17 is a diagram showing a modified example of the tread member 300. The tread member 300 shown in FIG. 17 also includes a sheet-like nonwoven fabric as the nonwoven body 302, similar to the example shown in FIG. 15. However, the tread member 300 shown in FIG. 17 is different from the example shown in FIG. 15 in that, in addition to the nonwoven fabric as the nonwoven body 302, it includes a rod-shaped core material 301 for winding the nonwoven fabric. The core material 301 can be constituted by, for example, a thin coil spring with a fine wire diameter and a dense pitch.

[0088] Figures 18A and 18B are diagrams showing a modified example of the tread member 300. The tread member 300 shown in Figures 18A and 18B includes a sheet-like nonwoven fabric as the nonwoven body 302, a rod-shaped core member 301, and a reinforcing member 303 interposed between the nonwoven fabric and the outside in the radial direction of the core member 301. The reinforcing member 303 may be formed in a cylindrical shape surrounding the outside in the radial direction of the core member 301. The reinforcing member 303 may be constituted by, for example, a coil spring with a dense pitch. The core member 301 is disposed inside the cylindrical reinforcing member 303. By providing the reinforcing member 303, the penetration of the core member 301 into the nonwoven fabric as the nonwoven body 302 can be suppressed as compared with the case where the reinforcing member 303 is not provided. Further, since the reinforcing member 303 protects the core member 301, the durability of the tread member 300 is improved. Further, the reinforcing member 303 stores and retains the heat transmitted from the wheel portion 10 or the like and the heat generated by the tread member 300, and can suppress the supercooling of the tread member 300 in an extremely low temperature environment.

[0089] Figures 19A and 19B are diagrams showing a modified example of the tread member 300. The tread member 300 shown in Figures 19A and 19B is different only in the cross-sectional shape of the nonwoven fabric as the nonwoven body 302 when it is embedded in the groove 230 as compared with the configuration shown in Figures 18A and 18B. As shown in Figures 19A and 19B, the nonwoven body 302 of the tread member 300 may have a gourd-shaped cross-sectional view. In this case, the tread member 300 has a fixed region a1 embedded in the groove 230 and a grounding region a2 that contacts the ground. The grounding region a2 is provided outside the fixed region a1 in the radial direction of the tire 1. In the tread member 300, the core member 301 and the reinforcing member 303 are provided in the fixed region a1. As shown in Figures 19A and 19B, in a cross-sectional view orthogonal to the longitudinal direction of the rod-shaped tread member 300, the width of the grounding region a2 is larger than the width of the fixed region a1. Further, the length of the grounding region a2 in the tire radial direction B is longer than the length of the fixed region a1 in the tire radial direction B.

[0090] In the present embodiment, the method for fixing the rod-shaped tread member 300 to the skeleton portion 2 is not particularly limited. The tread member 300 may further include, for example, a fixing portion for fixing to the skeleton portion 2. The fixing portion may be constituted by, for example, portions extending from both ends of the above-described core material 301 (see FIG. 17 etc.). The fixing portion may be fixed to, for example, the protruding screw tip of the above-described bolt 106 (see FIG. 7). By providing such a fixing portion, the tread member 300 becomes less likely to fall off from the skeleton portion 2.

[0091] Next, with reference to FIG. 20, a method for manufacturing the metal fiber 302a having a rectangular cross-sectional outer shape described above will be described. As shown in FIG. 20, the metal fiber 302a having a rectangular cross-sectional outer shape is obtained by winding a metal thin film 400 to form a roll body 401 of the metal thin film 400 and cutting the end face of this roll body 401 with a cutting blade 600. However, the manufacturing method shown in FIG. 20 is an example, and the manufacturing method of the metal fiber having a convex polygonal cross-sectional outer shape is not particularly limited.

[0092] As described above, according to the nonwoven fabric 302 including a plurality of metal fibers 302a having a rectangular cross-sectional outer shape shown in the present embodiment, a tread member 300 capable of improving traction performance can be realized. The cross-sectional outer shape of the metal fiber 302a is not limited to a rectangular shape, and even if it is other convex polygonal shapes, a tread member 300 capable of improving traction performance can be realized. Note that the use application of the nonwoven fabric 302 does not have to be the tread member 300 of the tire 1.

[0093] The nonwoven fabric and the tire according to the present invention are not limited to the specific configurations shown in the above-described embodiments, and various modifications, changes, and combinations are possible without departing from the scope of the claims. For example, in the above-described embodiment, the elastic deformation portion 202 of the main body spring 201 and the elastic deformation portion 212 of the connecting spring 211 are each configured by a coil spring, but the configuration is not limited thereto. The elastic deformation portion 202 of the main body spring 201 and / or the elastic deformation portion 212 of the connecting spring 211 may be configured to include a two-dimensional (i.e., extending along substantially the same plane) wave-shaped metal wire portion, for example, as shown in FIG. 21, instead of a coil spring. The example shown in FIG. 21 is an example in the case where the elastic deformation portion 202 and the elastic deformation portion 212 are formed in a two-dimensional wave shape. The wave-shaped metal wire portion may be, for example, a shape connecting semi-circles or a sine wave shape. Even in this case, the main body spring 201 and the connecting spring 211 can be connected by combining the wave-shaped metal wire portion of the main body spring 201 and the wave-shaped metal wire portion of the connecting spring 211. In other words, the main body spring 201 and the connecting spring 211 may be configured not to form a groove 230 (see FIG. 11 etc.) when combined with each other. Therefore, the tread member 300 is not limited to the configuration of being held in the groove 230. However, from the viewpoint of stably holding the tread member 300, it is preferable to use the main body spring 201 and the connecting spring 211 that partition the groove 230 when combined with each other as shown in the above-described embodiment.

[0094] Also, in the above-described embodiment, the tire 1 including a plurality of tread members 300 arranged without a gap in the tire circumferential direction C between two rim portions has been described, but the configuration is not limited thereto. As shown in FIGS. 22 to 24, a wheel portion 10 including three or more rim portions may be used. And, as shown in FIGS. 23 and 24, a configuration including a plurality (two in FIG. 23 and three in FIG. 24) of tread portions at different positions in the tire width direction A may be used.

[0095] Each of FIGS. 23(a) to 23(c) shows a tire 1 having two tread portions 4a and 4b at different positions in the tire width direction A. The tires 1 shown in FIGS. 23(a) to 23(c) differ in that the arrangement directions of the tread members 300 in the tread portions 4a and 4b are different. As shown in FIGS. 23(a) to 23(c), the arrangement direction of the rod-shaped tread members 300 is not particularly limited. Note that, as in the above-described embodiment, even if there is only one tread portion, the arrangement direction of the tread members 300 is not particularly limited. As shown in FIGS. 23(a) and 23(b), the tread members 300 may extend in a direction inclined with respect to the tire width direction A and the tire circumferential direction C in a tread surface view seen from the outside in the tire radial direction B. Further, as shown in FIG. 23(c), the tread members 300 may extend along the tire width direction A in a tread surface view seen from the outside in the tire radial direction B. Note that, also in the three tread portions 4a to 4c shown in FIG. 24, the arrangement direction of the tread members 300 is not particularly limited.

Industrial Applicability

[0096] The present invention relates to a nonwoven body and a tire.

Explanation of Reference Numerals

[0097] 1: Tire 2: Skeleton portion 4a, 4b, 4c: Tread portions 10: Wheel portion (rim member) 20: Ground contact deformation portion 101: First rim portion 102: Second rim portion 103: Connection portion 104: Support member 105: Fitting receiving portion 106: Bolt 107: Bolt hole 201: Main body spring 202: Elastic deformation portion 203: Locking portion 203a: Straight portion 203b: Bent portion 212: Elastic deformation portion 213: Restricting part 230: Groove 300: Tread member 301: Core material 302: Nonwoven fabric 302a: Metal fiber 303: Reinforcing member 400: Metal thin film 401: Roll body 501, 502, 503: Rim part 600: Cutting edge A: Tire width direction a1: Fixed area a2: Ground contact area B: Tire diameter direction C: Tire circumferential direction D: Central axis direction of elastic deformation part of connecting spring E: Central axis direction of ring shape of restricting part of connecting spring F: Extending direction of groove O: Central axis of elastic deformation part of connecting spring X: Particle Y: Traveling road surface

Claims

1. A skeleton part composed of a rim member, a plurality of main body springs locked to the rim member, and a plurality of connecting springs combined with the main body springs. Comprising at least a tread member disposed on the outer periphery of the skeleton part. The tread member is a tire including a non-woven fabric containing a plurality of metal fibers whose outer shape in a cross-section orthogonal to the longitudinal direction is a convex polygonal shape.

2. The tire according to Claim 1, wherein the outer shape of the metal fiber in the cross-section orthogonal to the longitudinal direction is rectangular.

3. The tire according to Claim 1 or 2, wherein the metal fiber is made of austenitic stainless steel or aluminum alloy.

4. The tire according to any one of Claims 1 to 3, wherein the non-woven fabric is composed only of a plurality of the metal fibers.

5. The tire according to any one of Claims 1 to 4, wherein a plurality of the metal fibers are mechanically entangled and integrated.

6. The non-woven fabric is a sheet-shaped non-woven cloth. The non-woven cloth is disposed on the outer periphery of the skeleton part such that at least a part of it is embedded in a groove partitioned by the main body spring and the connecting spring in a rounded rod-like form.

7. The tire according to Claim 6, wherein the non-woven cloth is rolled up such that a plurality of layers are laminated in the radial direction.

Images