Tire

Abstract

To provide a knit product from which a tread component having improved traction performance can be easily made, and a tire.SOLUTION: A knit product comprises knitted filaments comprising at least one metal fiber 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 knitted 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 springs such as coil springs, and due to the presence of numerous gaps between these springs, proper driving may not be possible depending on the driving environment. For example, when driving on sandy ground with the tire disclosed in Patent Document 1, sand may get into the gaps between the coil springs, causing the tire to sink into the ground. Furthermore, if sand enters the wheel's rotation center side through the gaps between the coil springs, and a drive mechanism or the like is located on the wheel's rotation center side, for example, this could cause a malfunction in the drive mechanism. Therefore, the driving performance, such as the expected driving force, may be reduced with the tire disclosed in Patent Document 1.

[0006] In contrast, the tire disclosed in Patent Document 2 includes a tread member positioned on the outer circumference of a skeletal structure made up of springs. Therefore, the tire disclosed in Patent Document 2 can suppress the aforementioned decrease in driving performance.

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

[0008] The present invention aims to provide a knitted body and a tire that facilitate the realization of a tread member capable of improving traction performance. [Means for solving the problem]

[0009] A knitted body according to a first aspect of the present invention is constructed by knitting together filament bodies, each containing at least one metal fiber whose cross-sectional shape perpendicular to the longitudinal direction is a convex polygonal shape. This configuration makes it easier to create tread components that can improve traction performance.

[0010] In one embodiment of the present invention, the outer shape of the metal fiber in a cross-section perpendicular to the longitudinal direction is rectangular. This configuration makes it easier to create tread components that can improve traction performance.

[0011] In one embodiment of the present invention, the metal fiber is made of austenitic stainless steel or an aluminum alloy. This configuration makes it possible to create a tread component that ensures durability in extremely low-temperature environments.

[0012] One embodiment of the present invention is a knitted body that is configured in an endless manner. This configuration makes it easier to create a tread material in which metal fibers are less likely to fall off.

[0013] In one embodiment of the present invention, the filament body is a multifilament composed of a plurality of metal fibers. This configuration ensures durability that makes it resistant to damage even in harsh environments.

[0014] One embodiment of the present invention is a knitted body constructed by knitting only the multifilaments. This configuration makes it easier to create tread components that can improve traction performance.

[0015] A tire according to a second aspect of the present invention comprises a rim member, a skeletal portion composed of a plurality of main springs locked to the rim member, and a plurality of connecting springs combined with the main springs, and a tread member disposed on the outer circumference of the skeletal portion, wherein the tread member includes the knitted body. This configuration makes it easier to create tread components that can improve traction performance.

[0016] In one embodiment of the present invention, the knitted body is arranged on the outer circumference of the skeletal portion in a rolled-up rod shape, such that at least a portion of it is embedded in a groove partitioned by the main body spring and the connecting spring. This configuration makes it easy to create a rod-shaped knitted body for the tread material.

[0017] As one embodiment of the present invention, the knit body is rolled up such 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.

Effects of the Invention

[0018] According to the present invention, it is possible to provide a knit body and a tire that can easily realize a tread member with improved traction performance.

Brief Description of the Drawings

[0019] [Figure 1] It is an external perspective view of a tire according to an embodiment of the present invention. [Figure 2] It is an external perspective view of the skeleton part of the tire of FIG. 1. [Figure 3] It is an external perspective view of the rim member of FIG. 2. [Figure 4] It is a schematic view showing an example of the main body spring that constitutes the grounding deformation part of FIG. 2. [Figure 5] It is a schematic view showing an example of the locking mode of the main body spring to the rim member. [Figure 6] It is a sectional view taken along the line I-I of FIG. 5. [Figure 7] It is a sectional view taken along the line II-II of FIG. 5. [Figure 8] It is a schematic view showing an example of the connecting spring that constitutes the grounding deformation part of FIG. 2. [Figure 9A] It is a schematic view for explaining an example of the coupling method of the connecting spring to the main body spring. [Figure 9B] It is a schematic view for explaining an example of the coupling method of the connecting spring to the main body spring. [Figure 10] It is a schematic view showing a modified example of the restricting part. [Figure 11] It is a view showing a state where a tread member is attached to a part of the skeleton part. [Figure 12] It is a view showing a state where a tread member is attached to a part of the skeleton part. [Figure 13A] This is a schematic cross-sectional view showing the state in which the tread member is attached to the frame. [Figure 13B] This figure shows the cross-sectional shape of the metal fibers in a knitted body according to one embodiment of the present invention. [Figure 14] Figures 14(a) to 14(c) show knitted bodies with different cross-sectional sizes of metal fibers. Figures 14(a) to 14(c) are conceptual diagrams showing the state in which the contact surface of the tread member, which is made of the knitted body shown in Figure 13B, is in contact with a road surface that has fine irregularities. [Figure 15] Figure 13A shows an example of the knitting structure of the tread material. [Figure 16] This figure shows a modified example of a tread material. [Figure 17A] This figure shows a modified example of a tread material. [Figure 17B] Figure 17A shows the structure of the knitted body and the method of wrapping it around the core material. [Figure 18A] This figure shows a modified example of a tread material. [Figure 18B] Figure 18A shows the structure of the knitted body and the method of wrapping it around the core material. [Figure 19A] This figure shows a modified example of a tread material. [Figure 19B] Figure 19A is an explanatory diagram illustrating the structure of the tread member. [Figure 20A] This figure shows a modified example of a tread material. [Figure 20B] Figure 20A is an explanatory diagram illustrating the structure of the tread member. [Figure 21] This figure shows an example of a method for manufacturing metal fibers with a rectangular cross-sectional shape. [Figure 22] This is a schematic diagram showing a modified example of the main spring and connecting spring. [Figure 23] This figure shows an example of a rim member having three rim sections. [Figure 24]Figures 23(a) to 23(c) show examples of the arrangement direction of tread members in two different tread sections. [Figure 25] This figure shows an example of a tire with four rim sections and three different tread sections. [Modes for carrying out the invention]

[0020] Hereinafter, embodiments of the knitted body and tire according to the present invention will be illustrated with reference to the drawings. Common components in each figure are denoted by the same reference numerals. In this specification, the tire width direction refers to the direction parallel to the tire's axis of rotation. The tire radial direction refers to the radial direction perpendicular to the tire's axis of rotation, centered on the axis of rotation. The tire circumferential direction refers to the direction in which the tire rotates around the tire's axis of rotation.

[0021] Figure 1 is an external perspective view of a tire 1 according to one embodiment of the present invention. The tire 1 according to this embodiment comprises a frame part 2 that defines the structure of the tire 1, and a tread member 300 that is mounted on the frame part 2.

[0022] <Skeletal part 2> Figure 2 is an external perspective view of the skeletal portion 2 of the tire 1. As shown in Figure 2, the skeletal portion 2 of the tire 1 in this embodiment comprises a wheel portion 10 as a rim member and a ground contact deformation portion 20 that can deform when in contact with the ground.

[0023] Figure 3 is an external perspective view of the wheel portion 10 of the frame portion 2 of the tire 1. The wheel portion 10 comprises a plurality of rim portions. As shown in Figures 2 and 3, the wheel portion 10 of this embodiment comprises two rim portions. More specifically, the wheel portion 10 of this embodiment comprises a first rim portion 101 and a second rim portion 102. The wheel portion 10 of this embodiment further comprises a plurality of connecting portions 103 that connect the first rim portion 101 and the second rim portion 102. The number of rim portions comprising the wheel portion 10 is not particularly limited. For example, the wheel portion 10 may comprise three or more rim portions. Wheel portions comprising three rim portions and wheel portions comprising four rim portions will be described later (see Figures 23 to 25).

[0024] 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 positioned at different locations in the tire width direction A such that their central axes are on the same axis. In this embodiment, the first rim portion 101 and the second rim portion 102 are configured to be the same size and shape. However, the first rim portion 101 and the second rim portion 102 may be configured to be of different sizes or shapes as long as they can perform their function as a tire 1. 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.

[0025] 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 Figure 3, the wheel portion 10 of this embodiment has six connecting portions 103, but the number of connecting portions 103 provided in the wheel portion 10 is not limited to this. Multiple connecting portions 103 are attached to one side of the annular first rim portion 101 and one side of the annular second rim portion 102, respectively. In this way, 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 to the first rim portion 101 and the second rim portion 102 will be referred to as the "inside in the tire width direction A", and the side to which the connecting portion 103 is not attached will be referred to as the "outside in the tire width direction A".

[0026] In this embodiment, the first rim portion 101 and the second rim portion 102 are provided with a fitting receiving portion 105 (see Figure 6) on the inner surface in the tire width direction A, which can accommodate the main spring 201 of the contact deformation portion 20. Details of the fitting receiving portion and the manner of fitting will be described later. In this specification, "fitting" means being fitted together, and "locking" broadly means being fastened, including the manner of fitting.

[0027] As shown in Figure 3, the wheel portion 10 as a rim member in this embodiment further includes a support member 104 that maintains the fitted state of the ground contact deformation portion 20 fitted into the fitting receiving portion 105 (see Figure 6). The support member 104 in this embodiment is attached to the first rim portion 101 and the second rim portion 102. The support member 104 may be fixed, for example, to the inside of the first rim portion 101 and the second rim portion 102 in the tire width direction A using bolts.

[0028] The ground contact deformation portion 20 of this embodiment is configured to be elastically deformable in the tire radial direction B. As shown in Figure 2, the ground contact deformation portion 20 of this embodiment comprises a main spring 201 and a connecting spring 211. The main spring 201 and the connecting spring 211 are made of metal.

[0029] Figure 4 is a schematic diagram showing an example of a main spring 201 that constitutes the ground contact deformation section 20 shown in Figure 2. The main spring 201 connects multiple rim sections. In this embodiment, the main spring 201 connects the first rim section 101 and the second rim section 102. Figure 23 shows a skeletal section 2 having three rim sections 501 to 503. As shown in Figure 23, when the wheel section 10 as the rim member of the skeletal section 2 has three rim sections 501 to 503, it is preferable that the main spring 201 connects all pairs of adjacent rim sections from the three rim sections 501 to 503 in the same manner as connecting the first rim section 101 and the second rim section 102 described above. Figure 25 shows a skeletal section 2 having four rim sections. Although not shown in detail, in the example shown in Figure 25, the same main spring 201 as in Figure 23 connects all pairs of adjacent rim sections from the four rim sections. However, in a skeletal structure 2 having three or more rim sections, it is also possible to configure it so that at least one pair of any two rim sections are connected.

[0030] As shown in Figure 4, the main spring 201 comprises an elastically deformable portion 202 and a locking portion 203. In this embodiment, the elastically deformable portion 202 is made of a coil spring. Here, a coil spring is a spring that deforms elastically in response to a load, and is wound in a coil shape (spirular shape) around a predetermined axis. Depending on the desired size and weight of the tire 1 and the required properties of the contact deformation portion 20, an elastically deformable portion 202 with appropriate material and elasticity can be used.

[0031] The locking portions 203 are provided at both ends of the elastically deformable portion 202. The locking portions 203 lock the main spring 201 to the wheel portion 10, which serves as the rim member. The locking portions 203 have a different shape from the elastically deformable portion 202. That is, in this embodiment, the locking portions 203 have a shape different from a coil shape.

[0032] In this embodiment, the locking portion 203 is made of a member integrated with the elastically deformable portion 202. As shown in Figure 4, the locking portion 203 in this embodiment is made of extended portions, which are parts of the material constituting the elastically deformable portion 202 that extend from both ends of the elastically deformable portion 202.

[0033] As shown in Figure 4, the locking portion 203 of this embodiment includes a straight portion 203a that extends linearly from both ends of the elastically deformable portion 202. Also, as shown in Figure 4, the locking portion 203 of this embodiment includes a bent portion 203b that is continuous with the tip side of the straight portion 203a opposite to the base end side connected to the elastically deformable portion 202 and is bent relative to the straight portion 203a. In this embodiment, in a side view of the main spring 201 (see Figure 4), the bent portion 203b is bent perpendicular to the straight portion 203a. In other words, the bent portion 203b of this embodiment is bent perpendicular to the straight portion 203a in the plane containing the axis of the main spring 201.

[0034] Here, with reference to Figures 5 to 7, the details of how the main spring 201 is engaged with the wheel portion 10 in this embodiment will be described. The main spring 201 is engaged with the wheel portion 10 as a rim member by having one of the two locking portions 203 provided at both ends fitted to the first rim portion 101 and the other locking portion 203 fitted to the second rim portion 102. Here, an example will be described in which one locking portion 203 is engaged with the wheel portion 10 while fitted to the first rim portion 101, but the other locking portion 203 is engaged with the wheel portion 10 while fitted to the second rim portion 102 in a similar manner.

[0035] Figure 5 is a schematic diagram showing an example of how the main spring 201 is engaged with the wheel portion 10. It is a schematic diagram of the state in which the main spring 201 is engaged with the wheel portion 10, as viewed from the inside of the first rim portion 101 in the tire width direction A. Although only a portion of the area where one of the engagement portions 203 of the main spring 201 is engaged is shown in Figure 5, in reality, one of the engagement portions 203 of the main spring 201 is engaged around the entire circumference of the first rim portion 101, as shown in Figure 5.

[0036] Figure 6 is a cross-sectional view of section II of Figure 5. Specifically, it is a cross-sectional view of the first rim portion 101 including the fitting receiving portion 105. As shown in Figure 6, in this embodiment, the main spring 201 is locked to the wheel portion 10 with the locking portion 203 fitted into the fitting receiving portion 105 provided on the inner surface of the first rim portion 101 in the tire width direction A. In this 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 in this embodiment is configured as a bottomed hole. It is preferable that the length of the hole in the extending direction of the fitting receiving portion 105 (depth of the hole) is longer than the length of the bent portion 203b. This allows the entire bent portion 203b to be inserted into the fitting receiving portion 105, making the fitted state more stable. However, the fitting receiving portion 105 may be configured as a through hole, which is a bottomless hole.

[0037] The cross-sectional shape of the hole in the fitting receiver 105 is not limited as long as the bent portion 203b fits inside, and may be, for example, oval, elliptical, rectangular, polygonal, etc. In order for the elastic deformation portion 202 to be locked more securely, it is preferable that the cross-sectional shape and size of the hole be approximately the same as the cross-sectional shape and size of the bent portion 203b.

[0038] As shown in Figure 6, the main spring 201 is positioned such that, with the bent portion 203b inserted into the fitting receiver 105, the elastically deformable portion 202 is located on the outside of the annular first rim portion 101 in the tire radial direction B (upper side in Figures 6 and 7), except for a portion of it. In this state, the support member 104 is attached to the first rim portion 101 on the inside of the first rim portion 101 in the tire width direction A (left side in Figures 6 and 7). As shown in Figure 6, the support member 104 is attached in a position that holds the bent portion 203b inserted into the hole of the fitting receiver 105, that is, in a position that prevents the bent portion 203b from coming out of the hole of the fitting receiver 105. Preferably, the support member 104 is attached in a position that closes the hole of the fitting receiver 105 when the main spring 201 is not inserted. Furthermore, as shown in Figure 6, the support member 104 sandwiches the straight portion 203a of the locking portion 203 between itself and 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 such that it sandwiches the straight portion 203a of the locking portion 203 between itself and the inner surface of the first rim portion 101 in the tire width direction A. In this way, the main body spring 201 of this embodiment is locked to the wheel portion 10 by sandwiching the straight portion 203a and the bent portion 203b of the locking portion 203 between the inner surface of the first rim portion 101 in the tire width direction A and the support member 104, with the bent portion 203b of the locking portion 203 fitted into the fitting receiving portion 105.

[0039] In this embodiment, the support member 104 is attached to the first rim portion 101 using, for example, a bolt 106. Figure 7 is a cross-sectional view taken along line II-II of Figure 5. More specifically, Figure 7 is a cross-sectional view of the area including the bolt 106 that fixes the support member 104 to the first rim portion 101. As shown in Figure 7, the support member 104 is fixed to the first rim portion 101 by the bolt 106. As shown in Figure 5, the support member 104 may be fixed to the first rim portion 101 at a position between the two main 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. This allows the support member 104 to be fixed to the first rim portion 101 without interfering with the locking position of the main springs 201.

[0040] As shown in Figures 5 to 7, the bolt 106 may be provided such that the threaded tip of the bolt 106 protrudes further inward in the tire width direction A than the inner surface of the support member 104 in the tire width direction A. The threaded 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, which will be described later.

[0041] The support member 104 may be configured as a single annular member, or it may be configured as a plurality of divided members that form an annular shape as a whole. In the case of the plurality of support members 104, two adjacent support members 104 may be arranged so that they touch or overlap at their ends in the tire circumferential direction C. Alternatively, two adjacent support members 104 may be arranged so that they are spaced apart at an appropriate interval in the tire circumferential direction C. If the support member 104 is configured as a plurality of divided members, each member may be, for example, fan-shaped.

[0042] Multiple main springs 201 are arranged at predetermined intervals in the tire circumferential direction C, extending over the entire area of ​​the tire circumferential direction C. One locking portion 203 of each of these multiple main springs 201 is locked to the wheel portion 10 by the aforementioned locking method utilizing the fitting receiving portion 105 of the first rim portion 101. Similarly, the other locking portion 203 of the main spring 201 is locked to the wheel portion 10 by the aforementioned locking method utilizing the fitting receiving portion 105 of the second rim portion 102. In this embodiment, one locking portion 203 and the other locking portion 203 of a single main 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 a straight line substantially parallel to the tire width direction A with respect to the first rim portion 101 and the second rim portion 102. In other words, in this embodiment, the two locking portions 203 of one main spring 201 may be fixed to the first rim portion 101 and the second rim portion 102 at the same position in the tire circumferential direction C. However, the two locking portions 203 of one main spring 201 may be fixed to the first rim portion 101 and the second rim portion 102 at different positions in the tire circumferential direction C.

[0043] The number of main springs 201 fitted to the first rim portion 101 and the second rim portion 102, and the spacing in the tire circumferential direction C, may be appropriately determined according to the size and weight of the tire 1 and the required properties of the contact deformation portion 20. The number of bolts 106 used to attach the support members 104 to the first rim portion 101 and the second rim portion 102, and the spacing in the tire circumferential direction C, may also be appropriately determined. For example, the bolts 106 do not necessarily have to be attached one at a time between two adjacent fitting receiving portions 105 in the tire circumferential direction C, as in this embodiment.

[0044] In the skeletal portion 2 of the tire 1 according to this embodiment, a ground contact deformation portion 20 is formed by connecting a connecting spring 211 to a plurality of main body springs 201 that are locked to the wheel portion 10 in this manner. That is, in this embodiment, the connecting spring 211 functions as a connecting member that connects adjacent main body springs 201. Figure 8 is a schematic diagram showing an example of a connecting spring 211 that constitutes the ground contact deformation portion 20 of Figure 2. In this embodiment, as shown in Figure 8, the connecting spring 211 comprises an elastic deformation portion 212 and a restricting portion 213. The connecting spring 211 is locked to the wheel portion 10 and is positioned between two adjacent main body springs 201 in the tire circumferential direction C. The connecting spring 211 is then combined with these two main body springs 201 and connected to them.

[0045] In this embodiment, the elastic deformation portion 212 is composed of a coil spring. The elastic deformation portion 212 can be made of an appropriate material and has appropriate elasticity depending on the desired size and weight of the tire 1 and the required properties of the ground contact deformation portion 20. The diameter of the coil spring constituting the elastic deformation portion 212 is preferably close to the diameter of the coil spring constituting the elastic deformation portion 202 of the main 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 constituting the elastic deformation portion 212 is to the diameter of the coil spring constituting the elastic deformation portion 202 of the main spring 201, the easier it is for the force to be applied evenly when the coil spring constituting the elastic deformation portion 202 and the coil spring constituting 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 springs constituting the elastic deformation section 202 and the coil springs constituting the elastic deformation section 212 can both be 15 mm to 25 mm, for example, 20 mm.

[0046] In this embodiment, the limiting portion 213 is provided at one end of the elastically deformable portion 212. No other mechanism is configured at the other end of the elastically deformable portion 212 where the limiting portion 213 is not provided; therefore, the elastically deformable portion 212 has a shape that appears to be interrupted at the other end. The limiting portion 213 limits the displacement of the connecting spring 211, which is connected to the main spring 201, relative to the main spring 201. The limiting portion 213 only needs to limit the displacement of the connecting spring 211 relative to the main spring 201 in at least one direction. In this way, by limiting the displacement of the connecting spring 211 relative to the main spring 201 with respect to the limiting portion 213, the connection position of the connecting spring 211 is determined and fixed when the connecting spring 211 is connected to the main spring 201, as will be explained later with reference to Figures 9A and 9B. That is, the connection state of the connecting spring 211 relative to the main spring 201 is positioned and fixed. The limiting portion 213 has a different shape from the elastically deformable portion 212. In other words, in this embodiment, the limiting portion 213 has a shape different from that of a coil.

[0047] In this embodiment, the limiting portion 213 is made of a member integrated with the elastic deformation portion 212. As shown in Figure 8, the limiting portion 213 in this embodiment is an extension portion made of the material constituting the elastic deformation portion 212 extending from one end of the elastic deformation portion 212. In the example shown in Figure 8, the limiting portion 213 has a ring-shaped portion formed by bending the wire forming the elastic deformation portion 212 into a ring shape. The ring shape is formed such that the direction intersecting the central axis direction D, which is parallel to the central axis O of the elastic deformation portion 212, is the central axis direction E. The ring-shaped portion of the limiting portion 213 may be of any size that can limit the displacement of the connecting spring 211. For example, the diameter of the ring-shaped portion of the limiting portion 213 may be configured to be 0.5 to 1.0 times the diameter of the elastic deformation portion 212.

[0048] Here, the function of the limiting section 213 will be explained along with the method of connecting the connecting spring 211 to the main spring 201. Figures 9A and 9B are schematic diagrams illustrating an example of how the connecting spring 211 is connected to the main spring 201.

[0049] As shown in Figure 9A, the connecting spring 211 is connected to the two adjacent main springs 201 by hooking its elastically deformable portion 212 onto the elastically deformable portion 202 of the main spring 201 which is locked to the wheel portion 10, thereby assembling with the two adjacent main springs 201. Specifically, the connecting spring 211 is connected to the main springs 201 in such a way that it restricts the relative displacement between the two main springs 201 adjacent to each other in the tire circumferential direction C. At this time, the connecting spring 211 is inserted into the main springs 201 as it rotates and moves forward, with the other end without the limiting portion 213 as the leading end, and is gradually assembled with the two adjacent main springs 201.

[0050] When the entire elastically deformable portion 212 of the connecting spring 211 is combined with the main spring 201, the restricting portion 213 eventually comes into contact with the main spring 201, as shown in Figure 9B. Due to its shape, the restricting portion 213 cannot be combined with the main spring 201. Therefore, the connecting spring 211 does not move in the insertion direction beyond the position where the restricting portion 213 is in contact with the main spring 201. In particular, after the ring-shaped portion of the restricting portion 213 comes into contact with the main spring 201, the connecting spring 211 will not move forward (in the insertion direction) even if one tries to move it forward while rotating it. In this way, the restricting portion 213 restricts the displacement of the connecting spring 211 relative to the main spring 201 in at least one direction. In this manner, the connecting state of the connecting spring 211 relative to the main spring 201 is positioned and fixed by the restricting portion 213. In addition, the connecting spring 211 connected to the main spring 201 becomes less likely to come off the main spring 201.

[0051] Furthermore, it is preferable that at least one of the ends of the connecting spring 211 is not fixed to the wheel portion 10. In this embodiment, neither end of the connecting spring 211 is fixed to the wheel portion 10. In other words, in this embodiment, both ends of the connecting spring 211 are unfixed. However, only one end of the connecting spring 211 may be fixed to the wheel portion 10. In this case, the end of the connecting spring 211 opposite to the end on which the limiting portion 213 is provided is fixed to the rim member.

[0052] In this embodiment, all main springs 201 locked to the wheel portion 10 are connected to each of two adjacent main springs 201 by connecting springs 211. In this embodiment, the frame portion 2 is constructed in this way. That is, in this embodiment, all main springs 201 of the ground contact deformation portion 20 of the frame portion 2 are connected to two connecting springs 211, and all connecting springs 211 of the ground contact deformation portion 20 of the frame portion 2 are connected to two main springs 201. In this way, by connecting the connecting springs 211 between two adjacent main springs 201, even when a load is applied to the frame portion 2, the distance between the main springs 201 does not spread too much, making it easier to maintain the function of the tire 1.

[0053] The connecting spring 211 that connects the two main springs 201 may be inserted from the first rim portion 101 side toward the second rim portion 102 side in the tire width direction A, or from the second rim portion 102 side toward the first rim portion 101 side. Preferably, half of the multiple connecting springs 211 provided on 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. This ensures that the limiting portions 213 of the connecting springs 211 are evenly distributed on both sides of the frame portion 2 in the tire width direction A, making it easier to balance the frame portion 2. It also prevents the limiting portions 213 from being densely concentrated on only one side of the frame portion 2 in the tire width direction A. In particular, it is even more preferable that two adjacent connecting springs 211 in the tire circumferential direction C are inserted from different directions. This makes it even easier to balance the skeletal structure 2.

[0054] Furthermore, the frame 2 may further include connecting members that connect the ring-shaped portions of the limiting portions 213 of the multiple connecting springs 211. The connecting members may be made of wire, for example. Let's assume that, for example, half of the multiple 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 limiting portion 213 of the connecting springs 211 inserted from the first rim portion 101 side toward the second rim portion 102 side is located toward the first rim portion 101 side in the tire width direction A, and the limiting portion 213 of the connecting springs 211 inserted from the second rim portion 102 side toward the first rim portion 101 side is located toward the second rim portion 102 side in the tire width direction A. In this case, the frame portion 2 may have two wires: one wire connecting the ring-shaped portions of the multiple limiting portions 213 located on the first rim portion 101 side in the tire width direction A, and another wire connecting the ring-shaped portions of the multiple limiting portions 213 located on the second rim portion 102 side in the tire width direction A.

[0055] The wires connecting the ring-shaped portions of the multiple limiting portions 213 located on the first rim portion 101 side are provided along the tire circumferential direction C so as to pass through the central openings of all the ring shapes of the multiple limiting portions 213 located on the first rim portion 101 side. Similarly, the wires connecting the ring-shaped portions of the multiple limiting portions 213 located on the second rim portion 102 side are provided along the tire circumferential direction C so as to pass through the central openings of all the ring shapes of the multiple limiting portions 213 located on the second rim portion 102 side. By providing such wires, the limiting portions 213 of the multiple connecting springs 211 can be connected to each other. As a result, the displacement of the relative positional relationship between the limiting portions 213 is restricted by the wires. Consequently, the connecting springs 211 coupled to the main spring 201 become even less likely to detach from the main spring 201.

[0056] However, the connecting member that connects the ring-shaped portions of the limiting portions 213 of the multiple connecting springs 211 does not necessarily have to be configured to pass through the central opening of the ring shape of the multiple limiting portions 213 as described above, and the limiting portions 213 may be connected to each other in any manner. In this case, for example, the connecting member may be fixed to each of the ring-shaped portions of the multiple limiting portions 213 to be connected, thereby connecting these ring-shaped portions of the multiple limiting portions 213. At a minimum, by providing a wire that connects the limiting portions 213 of the multiple connecting springs 211, the displacement of the relative positional relationship between the connecting springs 211 connected by the wire is restricted.

[0057] In the above embodiment, it was explained that the ring-shaped portion of the limiting portion 213 has a central axis direction E that intersects the central axis direction D, which is parallel to the central axis O of the elastically deformable portion 212. However, the shape of the limiting portion 213 is not limited to this. The limiting portion 213 may have any configuration that can limit the displacement of the connecting spring 211 relative to the main spring 201 in at least one direction.

[0058] Furthermore, in this embodiment, the limiting portion 213 is made of a member integrated with the elastically deformable portion 212, but the limiting portion 213 does not have to be made of a member integrated with the elastically deformable portion 212. For example, as schematically shown in Figure 10, the displacement of the connecting spring 211 relative to the main spring 201 may be limited by the limiting portion 213, which is made of an independent member different from the connecting spring 211. In the example shown in Figure 10, the limiting portion 213 is made of an independent member separate from the connecting spring 211, which limits the displacement of the contact point between the main spring 201 and the connecting spring 211 that are combined together.

[0059] The length of the connecting spring 211 may be appropriately determined according to the desired size and weight of the tire 1 and the required properties of the contact deformation portion 20. Preferably, 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 spring 201. Preferably, the connecting spring 211 has a length such that the elastic deformation portion 212 extends over the entire tire width direction A. This ensures that at least the area of ​​the elastic deformation portion 202 of the main spring 201 that makes contact with the ground in the tire width direction A is connected to the elastic deformation portion 212 of the connecting spring 211.

[0060] <Tread material 300> As shown in Figure 1, the tire 1 includes a tread member 300 arranged on the outer circumference of the frame portion 2 described above.

[0061] Figures 11 and 12 show the state in which the tread member 300 is attached to a part of the frame 2. More specifically, Figure 11 is a view of the frame 2 with the tread member 300 attached to a part of it, seen from the outside in the tire radial direction B. Figure 12 is a magnified view of a part of the frame 2 with the tread member 300 attached to a part of it.

[0062] As shown in Figures 1, 11, and 12, the tread member 300 is mounted on the contact area of ​​the contact deformation portion 20 of the frame 2, including the main spring 201 and the connecting spring 211. More specifically, the tread member 300 is mounted on the frame 2 so as to cover at least a portion of the outer side of the contact deformation portion 20 of the frame 2 in the tire radial direction B. Furthermore, as in this embodiment, it is preferable that the tread member 300 is mounted on the frame 2 so as to cover the outer side of the contact deformation portion 20 of the frame 2 in the tire radial direction B over the entire area of ​​the contact deformation portion 20 in the tire width direction A. Also, as in this embodiment, it is preferable that the tread member 300 is mounted on the frame 2 so as to cover the outer side of the contact deformation portion 20 of the frame 2 in the tire radial direction B over the entire area of ​​the tire circumferential direction C. In particular, as in this embodiment, it is preferable that the tread member 300 is mounted so as to cover the entire outer areas of both sides in the tire width direction A and the entire outer area in the tire radial direction B of the main spring 201 and the connecting spring 211 located between the first rim portion 101 and the second rim portion 102, over the entire area in the tire circumferential direction C, so that the main spring 201 and the connecting spring 211 are not exposed to the outside.

[0063] As shown in Figures 11 and 12, the outer surface of the frame 2 in the tire radial direction B is composed of a main spring 201 and a connecting spring 211 that are combined with each other. A groove 230 is formed on the outer surface of the frame 2 in the tire radial direction B by the combined main spring 201 and the connecting spring 211.

[0064] As described above, the positions of both ends of the main spring 201 that are locked to the wheel portion 10 in this embodiment are the same in the tire circumferential direction C. In other words, the multiple main springs 201 that constitute the ground contact deformation portion 20 in this embodiment have a radial structure that extends radially from the rotation axis of the tire 1 when viewed from the side along the rotation axis of the tire 1. Therefore, the connecting springs 211 woven with the main springs 201 also have a radial structure that extends radially from the rotation axis of the tire 1 when viewed from the side. In this way, when the main springs 201 and the connecting springs 211 have a radial structure that extends radially when viewed from the side of the tire, the grooves 230 are formed to extend in a direction that intersects with respect to the tire width direction A and the tire circumferential direction C, as shown in Figures 11 and 12. Hereafter, for the sake of convenience in explanation, the direction in which the grooves 230 extend will be referred to as the "extension direction F" (see Figure 11). In this embodiment, the pitch of the coil spring in the elastically deformable portion 202 of the main spring 201 and the pitch of the coil spring in the elastically deformable portion 212 of the connecting spring 211 are approximately equal.

[0065] As shown in Figures 11 and 12, in this embodiment, the tread member 300 is mounted in a groove 230 formed by the main spring 201 and the connecting spring 211. Figure 13A is a schematic cross-sectional view showing the approximate cross-section of the tread member 300 mounted in the groove 230, perpendicular to the extending direction F of the groove 230. As shown in Figure 13A, the tread member 300 is mounted such that at least a portion of it is embedded in the groove 230. By mounting the tread member 300 so that at least a portion of it is embedded in the groove 230, the tread member 300 becomes less likely to fall out of the groove 230. In this embodiment, only a portion of the tread member 300, that is, only the portion of the tread member 300 that is on the inside in the tire radial direction B (the lower portion in Figure 13A), is mounted so that it is embedded in the groove 230, and the portion of the tread member 300 that is on the outside in the tire radial direction B (the upper portion in Figure 13A) is exposed from the groove 230. In this case, vibrations during driving can be suppressed. However, the tread member 300 may be mounted so that its entirety is embedded in the groove 230. In this case, the tread member 300 is less likely to fall out of the groove 230. In this embodiment, as shown in Figure 1, the tread member 300 is embedded in all the grooves 230 formed in the frame 2. In this embodiment, the tread members 300 are arranged so as to be in contact with each other in the tire circumferential direction C. However, the tread member 300 does not have to be embedded in all the grooves 230. For example, the tread member 300 may be embedded in only a portion of the grooves 230 formed in the frame 2.

[0066] In this embodiment, it is preferable that the tread member 300 is detachably attached to the frame 2. By detachably attaching the tread member 300 to the frame 2, the tread member 300 can be removed from the frame 2 and replaced when it becomes worn out, etc.

[0067] As shown in Figure 13A, the tread member 300 includes a knitted body 302. More specifically, the tread member 300 of this embodiment shown in Figure 13A is composed of a knitted body 302. A knitted body refers to a knitted fabric formed by hooking filaments together to create a continuous loop-shaped stitch and spreading it out into a planar shape. In other words, a knitted body is formed by knitting filaments. The filaments constituting the knitted body may be one or more. Furthermore, it consists of one or more fibers that make up one filament. That is, the term "filament" in this specification is not limited to monofilaments composed of only one fiber, but also includes the concept of multifilaments composed of multiple fibers. Compared to woven fabrics composed of warp and weft threads, the knitted body 302 has filament bodies 700 that extend in a balanced manner in the vertical, horizontal, and diagonal directions within the plane, thus exhibiting more uniform strength in each direction. Therefore, when the tread member 300 is made of a knitted body 302, it can suppress damage when driving over uneven surfaces compared to when it is made of woven or nonwoven fabrics. In this embodiment, for the sake of explanation, the filament bodies 700 constituting the knitted body 302 will be described as a multifilament consisting of multiple metal fibers 302a, but the configuration of the filament bodies 700 is not limited to this configuration.

[0068] Figure 13B shows the cross-sectional shape (hereinafter simply referred to as "cross-sectional shape") perpendicular to the longitudinal direction of the metal fibers 302a that constitute the multifilament as the filament body 700 of the knitted body 302. As shown in Figure 13B, the knitted body 302 includes metal fibers 302a whose cross-sectional shape is rectangular. More specifically, the fibers constituting the knitted body 302 of this embodiment are only metal fibers 302a having the above-mentioned cross-sectional shape. That is, the knitted body 302 of this embodiment is composed of only one or more multifilaments, and each multifilament is composed only of multiple metal fibers 302a having the above-mentioned cross-sectional shape. Furthermore, as will be described in detail later, the tread member 300 of this embodiment is composed of a sheet-like knitted body 302 that has been rolled into a rod shape. Note that the above-mentioned "rectangle" means a quadrilateral (square or rectangle) where all corners are right angles.

[0069] In this embodiment, the cross-sectional shape of the metal fiber 302a is rectangular, but the cross-sectional shape of the metal fiber 302a is not limited to a rectangular shape. The cross-sectional shape of the metal fiber 302a can be any convex polygon shape, including a triangular shape, a rhombus, a parallelogram, a regular pentagon, etc. A "convex polygon" is a simple polygon that does not self-intersect, and a line segment connecting any two points inside or on its boundary does not go outside the polygon. As shown in Figure 13B, if such a metal fiber 302a is used to construct the contact surface 300b (the upper surface in Figure 13B) of the tread member 300, fine irregularities can be formed on the contact surface 300b of the tread member 300. Figures 14(a), 14(b), and 14(c) are conceptual diagrams showing the state in which the contact surface 300b of the tread member 300 shown in Figure 13B is in contact with a road surface that has fine irregularities formed thereon. Figures 14(a), 14(b), and 14(c) show a road surface Y composed of angular particles X, as an example of a road surface with fine irregularities. Examples of road surfaces Y composed of angular particles X include the lunar surface, which is covered with angular regolith with an average particle size of approximately 70 μm, and the seabed, which is covered with gravel. Figures 14(a), 14(b), and 14(c) differ only in the size of the cross-sectional outer shape of the metal fibers 302a that constitute the contact surface 300b of the tread member 300. As shown in Figures 14(a), 14(b), and 14(c), the fine irregularities formed on the contact surface 300b of the tread member 300 easily interlock with the fine irregularities of the road surface Y. Therefore, by configuring the contact surface 300b of the tread member 300 to have fine irregularities formed by metal fibers 302a, high traction performance can be achieved when driving on a road surface Y which has fine irregularities.

[0070] Furthermore, assuming a road surface Y composed entirely of angular particles X with an average particle size α, it is preferable that the length of each side (hereinafter referred to as "length of each side of the cross-section") β of the metal fiber 302a, which has a square cross-sectional shape, satisfies the following equation (Equation 1). Figure 14(a) shows the state where "β = √2α". Figure 14(b) shows the state where "β = √2α / 2". Figure 14(c) shows the state where "β = √2α / 4". By setting the length β of each side of the cross-section of the metal fiber 302a to √2α / 4 or more, it becomes easier to realize a metal fiber 302a with strength that is resistant to damage or breakage even when driving on the road surface Y. Also, by setting the length β of each side of the cross-section of the metal fiber 302a to √2α or less, it becomes easier to realize an uneven surface on the contact surface 300b that easily interlocks with the unevenness of the road surface Y.

[0071] √2α / 4 ≦ β ≦ √2α (Formula 1)

[0072] For example, when the nonwoven fabric 302 of this embodiment is used as the tread member 300 of a lunar rover, the average particle size of the regolith is approximately 70 μm. Therefore, based on (Equation 1) above, the length β of each side of the cross-section of the metal fiber 302a is preferably 24.7 μm ≤ β ≤ 98.9 μm.

[0073] Furthermore, assuming a road surface Y composed entirely of angular particles X with an average particle size α, it is preferable that the fiber-equivalent diameter γ of the metal fiber 302a, whose cross-sectional outer shape is a convex polygon, satisfies the following equation (Equation 2). Note that the fiber-equivalent diameter γ refers to the diameter of the circle obtained by converting the cross-sectional area of ​​the metal fiber 302a, whose cross-sectional outer shape is a convex polygon, to a circular area. Figure 14(a) shows a state in which the fiber-equivalent diameter γ of the metal fiber 302a is close to "2α". Figure 14(b) shows a state in which the fiber-equivalent diameter γ of the metal fiber 302a is close to "α". Figure 14(c) shows a state in which the fiber-equivalent diameter γ of the metal fiber 302a is close to "α / 2". By setting the fiber-equivalent diameter γ of the metal fiber 302a to α / 2 or more, it becomes easier to realize a metal fiber 302a with strength that is less likely to break or fracture even when driving on the road surface Y. Furthermore, by setting the fiber-equivalent diameter γ of the metal fiber 302a to 2α or less, it becomes easier to create a contact surface 300b that can easily interlock with the irregularities of the road surface Y.

[0074] α / 2 ≦ γ ≦ 2α (Formula 2)

[0075] For example, when the nonwoven fabric 302 of this embodiment is used as the tread member 300 of a lunar rover, the average particle size of the regolith is approximately 70 μm. Therefore, based on (Equation 2) above, the fiber-equivalent diameter γ of the metal fiber 302a is preferably 35 μm ≤ γ ≤ 140 μm.

[0076] In this way, by constructing the contact surface 300b of the tread member 300 with multiple metal fibers 302a having a convex polygonal cross-sectional shape, traction performance during driving on road surfaces with fine irregularities can be improved.

[0077] As described above, the tread member 300 of this embodiment is composed of a knitted body 302 that includes metal fibers 302a having a rectangular cross-sectional shape. Therefore, the traction performance described above can be obtained by forming the contact surface 300b of the tread member 300 with the portion that includes metal fibers 302a having a rectangular cross-sectional shape. More specifically, as described above, the fibers that constitute the knitted body 302 of this embodiment are only metal fibers 302a having a rectangular cross-sectional shape. Therefore, the contact surface 300b of the tread member 300 can be formed with any portion of the knitted body 302.

[0078] Furthermore, the fibers constituting the knitted body 302 may include fibers whose cross-sectional shape is not a convex polygon. Therefore, the knitted body 302 may be constructed by knitting together a multifilament as a filament body 700 consisting of a plurality of metal fibers 302a whose cross-sectional shape is a convex polygon, and a monofilament or multifilament as a filament body 700 consisting of fibers whose cross-sectional shape is not a convex polygon. However, it is preferable that 50% or more of the total fiber length constituting the knitted body 302 is the length of metal fibers 302a whose cross-sectional shape is a convex polygon, more preferably 67% or more is the length of metal fibers 302a whose cross-sectional shape is a convex polygon, even more preferably 75% or more is the length of metal fibers 302a whose cross-sectional shape is a convex polygon, and most preferably 100% is the length of metal fibers 302a whose cross-sectional shape is a convex polygon, as in this embodiment. In other words, it is most preferable that the knitted body 302 is composed solely of metal fibers 302a whose cross-sectional outer shape is a convex polygon. By doing so, it becomes easier to realize a tread member 300 that exhibits higher traction performance on a road surface Y (see Figures 14(a) to 14(c)) in which the aforementioned irregularities are formed.

[0079] The metal fiber 302a is preferably made of austenitic stainless steel or an aluminum alloy. Furthermore, it is preferable that all the fibers constituting the knit body 302 are made of metal, regardless of their cross-sectional shape, and it is particularly preferable that they be made of austenitic stainless steel or an aluminum alloy. By making all the fibers constituting the knit body 302 from austenitic stainless steel or an aluminum alloy, a structure that is resistant to breakage even in extremely low temperature environments can be achieved. In other words, by using such a knit body 302, a tread member 300 with durability in extremely low temperature environments can be realized. In particular, if the fibers constituting the knit body 302 are made of an aluminum alloy, not only is the above-mentioned durability ensured, but weight reduction is also easily achieved.

[0080] As shown in Figure 13A, the tread member 300 of this embodiment is composed of a sheet-like knitted body 302. As shown in Figure 13A, the sheet-like knitted body 302 is in the form of a rolled rod and is embedded in a groove 230 (see Figures 11 and 12) which is demarcated by a main spring 201 (see Figure 9A, etc.) and a connecting spring 211 (see Figure 9A, etc.). With this configuration, a rod-shaped tread member 300 can be easily realized from a sheet-like knitted body 302.

[0081] Furthermore, as shown in Figure 13A, it is preferable that the sheet-like knit body 302 is rolled up so that multiple layers are stacked radially. In this way, even if wear or chipping occurs in the outermost radial layer during driving, another layer with a similar configuration appears radially inward, making it difficult for the performance of the tread member 300 to deteriorate. Therefore, the deterioration of the performance of the tread member 300 due to wear or chipping can be suppressed, and the drivable distance can be extended.

[0082] As described above, the knitted body 302 is constructed by integrating the filament bodies 700 by knitting them together. Therefore, high strength can be ensured, and durability that makes it resistant to breakage even in environments with large temperature fluctuations or environments with high cosmic ray exposure, such as the lunar surface. Considering use in the harsh environments described above, it is preferable that the filament bodies 700 constituting the knitted body 302 are not joined together by adhesive or welding.

[0083] Figure 15 shows an example of the knitting structure of the filament body 700 of the knitted body 302 shown in Figure 13A. As shown in Figure 15, the knitted body 302 of this embodiment is spread out in a sheet shape by connecting the loop-shaped stitches of the filament body 700, so the filament body 700 and the metal fibers 302a constituting the knitted body 302 are extended in a balanced manner in the vertical, horizontal, and diagonal directions within the sheet surface. Therefore, when rolling up the sheet-like knitted body 302 to form a rod-shaped tread member 300, the winding direction (rolling direction) can be any winding direction, regardless of the extending direction of the filament body 700 and the metal fibers 302a constituting the filament body 700. The knitting method of the knitted body 302 of this embodiment is plain knit (stockinette stitch), but the knitting method is not particularly limited.

[0084] As described above, the knitted body 302 of this embodiment is constructed by knitting a multifilament as a filament body 700 consisting only of a plurality of metal fibers 302a with a rectangular cross-sectional shape. However, the configuration of the knitted body 302 is not limited to this configuration. The knitted body 302 is constructed by knitting a filament body 700 that includes at least one metal fiber 302a with a convex polygonal cross-sectional shape. If the knitted body 302 is constructed in this way, a tread member 300 that exhibits high traction performance on a road surface Y (see Figures 14(a) to 14(c)) with the above-described irregularities can be realized. However, from the viewpoint of achieving durability that is less likely to break even in harsh environments such as environments with large temperature changes or environments with high cosmic ray exposure such as the lunar surface, it is preferable that the filament body 700 constituting the knitted body 302 be a multifilament. Furthermore, the multifilaments constituting the knitted body 302 may be composed of multiple fibers bundled together without being twisted (untwisted yarn structure), but from the viewpoint of durability, it is more preferable to have multiple fibers twisted together (twisted yarn structure). Moreover, as described above, from the viewpoint of achieving higher traction performance on a road surface Y with irregularities (see Figures 14(a) to 14(c)), it is preferable that the knitted body 302 is constructed by knitting only multifilaments consisting only of metal fibers 302a with a convex polygonal cross-sectional shape (rectangular in this embodiment).

[0085] As shown in Figure 13A, the cross-sectional shape perpendicular to the longitudinal direction of the rod-shaped knitted body 302 constituting the tread member 300 of this embodiment is oval, but is not limited to this shape. The cross-sectional shape perpendicular to the longitudinal direction of the rod-shaped knitted body 302 may be, for example, circular or gourd-shaped (see Figures 20A and 20B).

[0086] Figure 16 shows a modified example of the tread member 300. The tread member 300 shown in Figure 16 also includes a knitted body 302, similar to the examples shown in Figures 13A and 13B. However, the tread member 300 shown in Figure 16 differs from the examples shown in Figures 13A and 13B in that, in addition to the knitted body 302, it includes a rod-shaped core material 301 for winding the knitted body 302. The core material 301 can be made, for example, of a coil spring with a thin wire diameter and a dense pitch.

[0087] Figure 17A shows a modified example of the tread member 300. The tread member 300 shown in Figure 17A comprises a knitted body 302 made up of filament bodies 700 consisting only of metal fibers 302a with a rectangular cross-sectional shape, similar to the configuration shown in Figure 16, and a core material 301 around which the knitted body 302 is wrapped. However, the knitted body 302 shown in Figure 17A differs from the configuration shown in Figure 16 in that it is configured in an endless manner. The endless knitted body 302 shown in Figure 17A is a flexible, seamless cylindrical body. Figure 17A shows the endless cross-section of the knitted body 302.

[0088] Figure 17B shows an example of a method for winding the endless knit body 302 shown in Figure 17A around a core material 301. As shown in Figure 17B, the endless knit body 302 is wound around the core material 301 with the core material 301 inserted through the endless knit body 302. This makes it more difficult for the core material 301 to fall off the endless knit body 302. Therefore, the endless knit body 302 is wound around the core material 301 in a state where it is flattened and stacked in two layers, except for the starting point of winding around the core material 301. Note that the core material 301 around which the endless knit body 302 is wound does not necessarily have to be inserted through the knit body 302. However, as mentioned above, from the viewpoint of preventing it from falling off, it is preferable that the core material 301 is inserted through the knit body 302.

[0089] In the tread member 300 shown in Figures 17A and 17B, the endless knit body 302 does not have the endless axis direction (the direction connecting the open ends on both sides) as the winding direction around the core material 301 (the same as the winding direction of the knit body 302). In the endless knit body 302 shown in Figures 17A and 17B, the endless axis direction is the winding center axis direction, and the direction perpendicular to the endless axis direction is the winding direction around the core material 301. That is, the endless knit body 302 shown in Figures 17A and 17B has the winding center axis in the direction along the endless axis direction, and is wound around this winding center axis. With this configuration, the open ends of the knit body 302 can be positioned at both ends in the longitudinal direction of the core material 301, so that the open ends of the knit body 302 are less likely to be exposed on the outside of the tire radial direction B of the tread member 300. In other words, the endless knitted body 302 shown in Figures 17A and 17B makes it easier to realize a tread member 300 in which the metal fibers 302a constituting the filament body 700 are less likely to fall off. Furthermore, it makes it easier to realize a tread member 300 that is less likely to break even in harsh temperature environments such as extremely low temperatures or high temperatures, or in environments with high cosmic ray exposure such as the lunar surface.

[0090] Furthermore, the open ends on both sides of the endless knit body 302 can be, for example, pushed inward in the tire width direction A of the wheel portion 10 (see Figure 3, etc.) which serves as the rim member of the skeletal portion 2, so as not to be exposed to the outside.

[0091] Figure 18A shows a modified example of the tread member 300. The tread member 300 shown in Figure 18A comprises a knitted body 302 made of filament bodies 700 consisting only of metal fibers 302a with a rectangular cross-sectional shape, similar to the configuration shown in Figure 16, and a core material 301 around which the knitted body 302 is wrapped. However, the knitted body 302 shown in Figure 18A differs from the configuration shown in Figure 16 in that it is configured in an endless manner. The endless knitted body 302 shown in Figure 18A is also a flexible, seamless cylindrical body, similar to the configurations shown in Figures 17A and 17B. However, the method of wrapping the knitted body 302 around the core material 301 differs from the configurations shown in Figures 17A and 17B.

[0092] Figure 18B shows an example of a method for winding the endless knitted body 302 shown in Figure 18A around the core material 301. As shown in Figure 18B, the endless knitted body 302 is wound spirally around the core material 301. Preferably, each circumferential portion of the knitted body 302 wound around the core material 301 is in contact with or overlaps with adjacent portions in the longitudinal direction of the core material 301. This makes it difficult for gaps to form in the tread member 300 and prevents foreign matter from entering the tire 1.

[0093] In the tread member 300 shown in Figures 18A and 18B, the endless knit body 302 is wound around the core material 301 with the endless axis direction (the direction connecting the open ends on both sides) as the winding direction. More specifically, the endless knit body 302 shown in Figures 18A and 18B has the winding center axis direction perpendicular to the endless axis direction, and the winding direction around the core material 301 is the endless axis direction. That is, the endless knit body 302 shown in Figures 18A and 18B has the winding center axis direction perpendicular to the endless axis direction, and is wound spirally around this winding center axis. With this configuration, the open ends of the knit body 302 can be positioned at both ends in the longitudinal direction of the core material 301. Therefore, the open ends of the knit body 302 are less likely to be exposed on the outside of the tire radial direction B of the tread member 300. This suppresses the shedding of the metal fibers 302a that constitute the filament body 700. Furthermore, it becomes easier to create a tread component 300 that is highly durable and resistant to damage even in harsh temperature environments such as extremely low or high temperatures, or in environments with high levels of cosmic ray exposure, such as the lunar surface.

[0094] Figures 19A and 19B show a modified example of the tread member 300. The tread member 300 shown in Figures 19A and 19B comprises a knitted body 302, a rod-shaped core material 301, and a reinforcing member 303 interposed between the core material 301 and the knitted body 302 on the radially outer side of the core material 301. The reinforcing member 303 may be cylindrical in shape, surrounding the radially outer side of the core material 301. The reinforcing member 303 may be made of, for example, a coil spring with a dense pitch. The core material 301 is placed inside the cylindrical reinforcing member 303. By providing the reinforcing member 303, the intrusion of the core material 301 into the knitted body 302 can be suppressed compared to the case without the reinforcing member 303. In addition, the durability of the tread member 300 is improved by the protection of the core material 301 by the reinforcing member 303. Furthermore, the reinforcing member 303 stores and retains heat transferred from the wheel portion 10 and the heat emitted by the tread member 300, thereby suppressing overcooling of the tread member 300 in an extremely low temperature environment.

[0095] Furthermore, the tread member 300 shown in Figures 19A and 19B may be constructed by rolling up a sheet-like knitted body 302, as shown in Figure 16. Also, the tread member 300 shown in Figures 19A and 19B may be constructed by rolling up an endless knitted body 302, as shown in Figures 17A and 17B. Moreover, the tread member 300 shown in Figures 19A and 19B may be constructed by spirally winding an endless knitted body 302, as shown in Figures 18A and 18B.

[0096] Figures 20A and 20B show a modified example of the tread member 300. The tread member 300 shown in Figures 20A and 20B differs from the configuration shown in Figures 19A and 19B only in the cross-sectional shape of the knitted body 302 when embedded in the groove 230. As shown in Figures 20A and 20B, the knitted body 302 of the tread member 300 may have a gourd-like shape in cross-section. In this case, the tread member 300 has a fixed area a1 embedded in the groove 230 and a contact area a2 that makes contact with the ground. The contact area a2 is provided on the outside in the tire radial direction B relative to the fixed area a1. The tread member 300 is provided with a core material 301 and a reinforcing member 303 in the fixed area a1. As shown in Figures 20A and 20B, in a cross-sectional view perpendicular to the longitudinal direction of the rod-shaped tread member 300, the width of the contact area a2 is greater than the width of the fixed area a1. Furthermore, the length of the tire radial B in the contact area a2 is longer than the length of the tire radial B in the fixed area a1.

[0097] Furthermore, the tread member 300 shown in Figures 20A and 20B may be constructed by rolling up a sheet-like knitted body 302, as shown in Figure 16. Also, the tread member 300 shown in Figures 20A and 20B may be constructed by rolling up an endless knitted body 302, as shown in Figures 17A and 17B. Moreover, the tread member 300 shown in Figures 20A and 20B may be constructed by spirally winding an endless knitted body 302, as shown in Figures 18A and 18B.

[0098] In this embodiment, the method of fixing the rod-shaped tread member 300 to the frame 2 is not particularly limited. The tread member 300 may further include, for example, a fixing portion for fixing to the frame 2. The fixing portion may be composed of, for example, portions extending from both ends of the core material 301 (see Figure 16, etc.) described above. The fixing portion may be fixed, for example, to the protruding threaded end of the bolt 106 (see Figure 7) described above. By providing such a fixing portion, the tread member 300 becomes less likely to fall off the frame 2.

[0099] Next, with reference to Figure 21, a method for manufacturing the metal fiber 302a having a rectangular cross-sectional shape will be described. As shown in Figure 21, the metal fiber 302a having a rectangular cross-sectional shape is obtained by winding a thin metal film 400 to form a roll body 401 of the thin metal film 400, and cutting the end face of this roll body 401 with a cutting blade 600. However, the manufacturing method shown in Figure 21 is just one example, and the method for manufacturing metal fibers having a convex polygonal cross-sectional shape is not particularly limited.

[0100] Furthermore, the method for knitting the filament bodies 700 that constitute the knitted body 302 is not particularly limited. The knitted body 302 can be formed, for example, using various knitting machines corresponding to different knitting methods.

[0101] As described above, the knitted body 302 shown in this embodiment, which is constructed by knitting together filament bodies 700 containing at least one metal fiber 302a having a rectangular cross-sectional shape, makes it possible to realize a tread member 300 capable of improving traction performance. As mentioned above, the cross-sectional shape of the metal fiber 302a is not limited to a rectangular shape; even if it has other convex polygonal shapes, a tread member 300 capable of improving traction performance can be realized. Note that the knitted body 302 may not be used for purposes other than the tread member 300 of a tire 1.

[0102] The knitted body and tire according to the present invention are not limited to the specific configurations shown in the embodiments described above, and various modifications, changes, and combinations are possible as long as they do not depart from the scope of the claims. For example, in the embodiments described above, the elastic deformation portion 202 of the main spring 201 and the elastic deformation portion 212 of the connecting spring 211 are each made of coil springs, but the invention is not limited to this configuration. The elastic deformation portion 202 of the main spring 201 and / or the elastic deformation portion 212 of the connecting spring 211 may be made by including a two-dimensional (i.e., extending along substantially the same plane) corrugated metal wire portion instead of a coil spring, for example, as shown in Figure 22. The example shown in Figure 22 is an example in which the elastic deformation portion 202 and the elastic deformation portion 212 are formed in a two-dimensional corrugated shape. The corrugated metal wire portion may be, for example, a shape of connected semicircles, or a sinusoidal shape. Even in this case, the main spring 201 and the connecting spring 211 can be connected by combining the corrugated metal wire portion of the main spring 201 and the corrugated metal wire portion of the connecting spring 211. In other words, the main spring 201 and the connecting spring 211 may be configured not to form a groove 230 (see Figure 11, etc.) when combined with each other. Therefore, the tread member 300 is not limited to a configuration in which it is held within the groove 230. However, from the viewpoint of stable holding of the tread member 300, it is preferable to have a main spring 201 and a connecting spring 211 that partition the groove 230 when combined with each other, as shown in the embodiment described above.

[0103] Furthermore, although the above-described embodiment described a tire 1 having a plurality of tread members 300 arranged without gaps in the tire circumferential direction C between two rim portions, the configuration is not limited to this. As shown in Figures 23 to 25, the wheel portion 10 may have three or more rim portions. And, as shown in Figures 24 and 25, the configuration may have a plurality of tread portions (two in Figure 24, three in Figure 25) at different positions in the tire width direction A.

[0104] Figures 24(a) to 24(c) each show a tire 1 having two tread sections 4a and 4b at different positions in the tire width direction A. The tires 1 shown in Figures 24(a) to 24(c) differ in that the arrangement direction of the tread members 300 in the tread sections 4a and 4b is different. As shown in Figures 24(a) to 24(c), the arrangement direction of the rod-shaped tread members 300 is not particularly limited. Furthermore, as in the embodiment described above, even with only one tread section, the arrangement direction of the tread members 300 is not particularly limited. As shown in Figures 24(a) and 24(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 when viewed from the outside of the tire radial direction B on the tread surface. Also, as shown in Figure 24(c), the tread members 300 may extend along the tire width direction A when viewed from the outside of the tire radial direction B on the tread surface. Furthermore, in the three tread sections 4a to 4c shown in Figure 25, the arrangement direction of the tread members 300 is not particularly limited. [Industrial applicability]

[0105] This invention relates to knitted bodies and tires. [Explanation of Symbols]

[0106] 1: Tires 2: Skeletal part 4a, 4b, 4c: Tread section 10: Wheel section (rim component) 20: Ground contact deformation part 101: First rim section 102: Second rim section 103: Connection part 104: Support member 105: Fitting receiver 106: Bolt 107: Bolt hole 201: Main spring 202: Elastic deformation part 203: Locking part 203a: Straight section 203b: Bent part 212: Elastic deformation part 213: Restriction section 230: Groove 300: Tread material 300b: Ground plane 301: Core material 302: Knitted body 302a: Metallic fiber 303: Reinforcement member 400: Metal Thin Film 401: Roll type 501, 502, 503: Rim section 600: Cutting blade 700: Filament A: Tire width direction a1: Fixed area a2: Grounding area B: Tire radial direction C: Tire circumferential direction D: Center axis of the elastically deformed part of the connecting spring E: The central axis of the ring shape of the limiting part of the connecting spring F: Direction of groove extension O: Central axis of the elastically deformed part of the connecting spring X: Particle Y: Driving surface

Claims

1. A knitted body comprising a knitted filament body including at least one metal fiber whose cross section perpendicular to the longitudinal direction has a convex polygonal outer shape.

2. The knitted body according to claim 1 , wherein the metal fibers have a rectangular cross section perpendicular to the longitudinal direction.

3. The knitted body according to claim 1 or 2, wherein the metal fibers are made of austenitic stainless steel or an aluminum alloy.

4. 4. The knitted body according to claim 1, which is configured in an endless shape.

5. The knitted body according to claim 1 , wherein the filament body is a multifilament made up of a plurality of the metal fibers.

6. The knitted body according to claim 5 , wherein only the multifilaments are knitted.

7. a framework configured with a rim member, a plurality of main body springs engaged with the rim member, and a plurality of connecting springs combined with the main body springs; At least a tread member disposed on an outer periphery of the skeleton, A tire, wherein the tread element comprises the knitted body according to any one of claims 1 to 6.

8. 8. The tire according to claim 7, wherein the knit body is in the form of a rolled rod and is arranged on the outer periphery of the skeleton portion so that at least a portion of the knit body is embedded in a groove defined by the main spring and the connecting spring.

9. The tire of claim 8 , wherein the knitted body is rolled so that multiple layers are stacked radially.

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