Patent Description:
Tires including coil springs are conventionally known. For example, Patent Literature (PTL) <NUM> discloses a tire in which a respective plurality of coil springs are interlaced with other coil springs and secured to annular rims to form a toroidal shape as a whole.

However, in a tire as disclosed in PTL <NUM>, a wheel includes springs such as coil springs, and due to existence of a large number of voids between the springs, the tire may not be able to be used as appropriate depending on a running environment. For example, in a case in which the tire disclosed in PTL1 is used on sandy ground or the like, the tire may be buried in the ground due to sand that enters gaps between the coil springs. In addition, the sand may enter the center of rotation of the wheel through the gaps between the coil springs and cause an abnormality of a drive mechanism, for example, in a case in which there is a drive mechanism or the like in the center of rotation of the wheel. Accordingly, the tire disclosed in PTL <NUM> may cause deterioration in desired running performance, such as driving force.

It would be helpful to provide a tire, configured with springs, that is less likely to cause deterioration in running performance.

A tire includes: a skeleton portion including a rim member, a plurality of body springs latched on the rim member, and a plurality of interlink springs interlaced with the body springs; and a tread member disposed at least on the outer periphery of the skeleton portion.

It is possible to provide a tire, configured with springs, that is less likely to cause deterioration in running performance.

An embodiment of the invention will be exemplarily described below with reference to the drawings.

<FIG> is an external perspective view of a tire <NUM>. The tire <NUM> includes a skeleton portion <NUM> that defines the structure of the tire <NUM> and tread members <NUM> mounted on the skeleton portion <NUM>.

<FIG> is an external perspective view of the tire <NUM>. As illustrated in <FIG>, the skeleton portion <NUM> of the tire <NUM> includes a wheel portion <NUM> having a rim portion, and a grounding deformable portion <NUM> that is deformable while being grounded.

<FIG> is an external perspective view of the wheel portion <NUM> of <FIG>. The wheel portion <NUM> is provided with a plurality of rim members. In the present embodiment, as illustrated in <FIG> and <FIG>, the wheel portion <NUM> is provided with, as the rim members, a first rim member <NUM> and a second rim member <NUM>. The number of the plurality of rim members provided in the wheel portion <NUM> does not necessarily have to be two as in the present embodiment, but can be two or more. In the present embodiment, as illustrated in <FIG>, the wheel portion <NUM> is further provided with a plurality of connection members <NUM>.

The first rim member <NUM> and the second rim member <NUM> are made of metal or resin. The first rim member <NUM> and the second rim member <NUM> are disposed at different positions on the same axis. The first rim member <NUM> and the second rim member <NUM> are each formed in an annular shape. In the present embodiment, the first rim member <NUM> and the second rim member <NUM> are configured to be the same size and shape. However, as long as the tire <NUM> can perform functions as a tire, the first rim member <NUM> and the second rim member <NUM> may be configured in different sizes or shapes. The outer diameter of the first rim member <NUM> and the second rim member <NUM> may be determined according to the size of the tire <NUM> required.

The connection members <NUM> are members that connect between the first rim member <NUM> and the second rim member <NUM>. The connection members <NUM> are made of metal or resin. In the present embodiment, as illustrated in <FIG>, the wheel portion <NUM> is provided with six connection members <NUM>, but the number of the connection members <NUM> provided in the wheel portion <NUM> is not limited thereto. The plurality of connection members <NUM> are attached to one side of the annular first rim member <NUM> and one side of the annular second rim member <NUM>. In this specification, in the wheel portion <NUM>, the side on which the connection members <NUM> are attached to the first rim member <NUM> and the second rim member <NUM> is referred to as an inner side in a tire width direction, and the side on which the connection members <NUM> are not attached is referred to as an outer side in the tire width direction.

In the present embodiment, the first rim member <NUM> and the second rim member <NUM> have, in inner surfaces in the tire width direction, engagement receiving portions <NUM> (see <FIG>) in which body springs <NUM> of the grounding deformable portion <NUM> are engaged. Details of the engagement receiving portions and an aspect of engagement will be described later. In this specification, "engagement" refers to being fitted together, and "latching" refers broadly to being fastened together, including being fitted together.

In the present embodiment, as illustrated in <FIG>, a support member <NUM> is attached to each of the first rim member <NUM> and the second rim member <NUM>. The support member <NUM> is a member that maintains a state of engaging the grounding deformable portion <NUM> in the engagement receiving portions <NUM> (see <FIG>). The support members <NUM> can be secured to the inner side of the first rim member <NUM> and the second rim member <NUM> in the tire width direction using, for example, bolts.

In the present embodiment, the grounding deformable portion <NUM> is configured with members including elastic deformable portions. In the present embodiment, as illustrated in <FIG>, the grounding deformable portion <NUM> includes two kinds of members: body springs <NUM> and interlink springs <NUM>. The body springs <NUM> and the interlink springs <NUM> are made of metal.

<FIG> is a schematic diagram illustrating an example of the body spring <NUM> that configures the grounding deformable portion <NUM> of <FIG>. The body springs <NUM> connect between the plurality of rim members. In the present embodiment, the body springs <NUM> connect between the first rim member <NUM> and the second rim member <NUM>. In a case in which the skeleton portion <NUM> has three or more rim members, the body springs <NUM> may connect at least one of spaces between the adjacent rim members, though it is preferable that the body springs <NUM> connect the respective spaces between the adjacent rim members in a manner similar to the manner of connecting between the first rim member <NUM> and the second rim member <NUM> described herein. As illustrated in <FIG>, the body spring <NUM> has an elastic deformable portion <NUM> and latch portions <NUM>.

In the present embodiment, the elastic deformable portion <NUM> is constituted of a coil spring. Here, the coil spring refers to a spring that deforms elastically in response to a load and is coiled (spirally wound) around a predetermined axis. The elastic deformable portion <NUM> that is made of a suitable material and has appropriate elasticity can be used according to the size and weight of the tire <NUM>, required properties of the grounding deformable portion <NUM>, and the like.

The latch portions <NUM> are provided at both ends of the elastic deformable portion <NUM>. The latch portions <NUM> latch the body spring <NUM> to the wheel portion <NUM>. The latch portions <NUM> have a different shape from the elastic deformable portion <NUM>. That is, in the present embodiment, the latch portions <NUM> have a shape different from a coil shape.

In the present embodiment, the latch portions <NUM> are constituted of members integral with the elastic deformable portion <NUM>. That is, in the present embodiment, as illustrated in <FIG>, for example, a material composing the elastic deformable portion <NUM> extends from both the ends of the elastic deformable portion <NUM> to configure the latch portions <NUM>.

In the present embodiment, as illustrated in <FIG>, for example, the latch portions <NUM> include straight portions 203a that are formed in a linear shape and are joined to both the ends of the elastic deformable portion <NUM>. Also in the present embodiment, as illustrated in <FIG>, for example, the latch portions <NUM> include, at tip ends of the straight portions 203a, bent portions 203b that are bent with respect to the straight portions 203a. In the present embodiment, the bent portions 203b are bent orthogonally with respect to the straight portions 203a in a side view of the body spring <NUM> (in a plane containing an axis of the body spring <NUM>).

Referring to <FIG>, an aspect of engaging the body springs <NUM> in the wheel portion <NUM> will be described in detail. One of the latch portions <NUM> provided at both the ends of the body spring <NUM> is engaged in the first rim member <NUM>, and the other latch portion <NUM> is engaged in the second rim member <NUM>. An example of a case in which one of the latch portions <NUM> is engaged in the first rim member <NUM> will be described here, but the other latch portion <NUM> can be engaged in the second rim member <NUM> in the same manner.

<FIG> is a schematic diagram illustrating an example of an aspect of engaging the body springs <NUM> in the first rim member <NUM>, in which an engagement state of the body springs <NUM> is viewed from the inner side of the first rim member <NUM> in the tire width direction. <FIG> illustrates only part of the first rim member <NUM> in which the body springs <NUM> are engaged, but the body springs <NUM> are practically engaged, as illustrated in <FIG>, over the entire circumference of the first rim member <NUM> in the first rim member <NUM>.

In the present embodiment, as illustrated in <FIG>, the body springs <NUM> can be engaged in the first rim member <NUM> by engaging the latch portions <NUM> in the engagement receiving portions <NUM> provided in a surface of the first rim member <NUM> on the inner side in the tire width direction. In the present embodiment, in particular, the engagement receiving portion <NUM> is configured as a hole into which the bent portion 203b of the latch portion <NUM> is insertable. Inserting the bent portions 203b into the holes of the engagement receiving portions <NUM> allows the body springs <NUM> to be engaged in the first rim member <NUM>. In a state of engaging the latch portions <NUM> in the engagement receiving portions <NUM>, the support member <NUM> is attached to the inner side of the first rim member <NUM> in the tire width direction in order to firmly secure the engagement state of the latch portions <NUM>.

<FIG> is a cross sectional view taken on the line A-A of <FIG>, and specifically, a cross sectional view of the first rim member <NUM> at a point including the engagement receiving portion. As illustrated in <FIG>, the first rim member <NUM> has the engagement receiving portion <NUM>. In the present embodiment, the engagement receiving portion <NUM> is configured as a hole into which the bent portion 203b is insertable. In the present embodiment, the engagement receiving portion <NUM> is configured as a bottomed hole. The length of the hole (depth of the hole) of the engagement receiving portion <NUM> in an extending direction is preferably longer than the length of the bent portion 203b. As a result, the entire bent portion 203b can be inserted into the engagement receiving portion <NUM>, and the engagement state becomes more stable. However, the engagement receiving portion <NUM> may be configured as a bottomless hole (through hole).

The shape of cross section of the hole of the engagement receiving portion <NUM> is not limited as long as the bent portion 203b is insertable thereinto, and may be, for example, an ellipse, an oval, a rectangle, a polygon, or the like. In order to latch (secure) the elastic deformable portion <NUM> more reliably, it is preferable that the shape and size of cross section of the hole are approximately the same as the shape and size of cross section of the bent portion 203b.

The body spring <NUM> is arranged such that, in a state of inserting the bent portion 203b into the engagement receiving portion <NUM>, the elastic deformable portion <NUM> is positioned, except for at least part, at a radially outer side (upper side in <FIG>) of the tire <NUM> of the annular first rim member <NUM>. In this state, the support member <NUM> is attached to the inner side (left side in <FIG>) of the first rim member <NUM> in the tire width direction. The support member <NUM> is attached, as illustrated in <FIG>, for example, to such a position as to retain the bent portion 203b inserted into the hole of the engagement receiving portion <NUM>, i.e., such a position as to prevent the bent portion 203b from slipping out of the hole of the engagement receiving portion <NUM>. The support member <NUM> is preferably attached in such a position as to block the hole of the engagement receiving portion <NUM> in a state of not inserting the body spring <NUM>. Also, as illustrated in <FIG>, for example, the support member <NUM> is secured to the first rim member <NUM> so as to retain the straight portion 203a of the latch portion <NUM> on the inner surface of the first rim member <NUM> in the tire width direction. In this manner, the engagement state of the latch portion <NUM> is stably secured by the support member <NUM>.

The support member <NUM> is attached to the first rim member <NUM> using, for example, bolts <NUM>. <FIG> is a cross sectional view of <FIG> taken on the line B-B, and specifically, a cross sectional view of the first rim member <NUM> at a point including the bolt <NUM> for securing the support member <NUM>. As illustrated in <FIG>, the support member <NUM> is secured to the first rim member <NUM> by the bolt <NUM>. As illustrated in <FIG>, the support member <NUM> may be secured to the first rim member <NUM> at a position between (in the middle of) the two body springs <NUM> that are engaged in the first rim member <NUM>. That is, in the first rim member <NUM>, one bolt hole <NUM> for securing the bolt <NUM> is formed between the two adjacent engagement receiving portions <NUM> in a circumferential direction of the annular first rim member <NUM>. Thereby, it is possible to secure the support member <NUM> to the first rim member <NUM> without interfering with engagement positions of the body springs <NUM>.

As illustrated in <FIG>, the bolt <NUM> may be provided such that a threaded end of the bolt <NUM> protrudes inward in the tire width direction of the wheel portion <NUM>, relative to an inner surface of the support member <NUM> in the tire width direction. The threaded end of the bolt <NUM>, which protrudes inward in the tire width direction of the wheel portion <NUM> relative to the inner surface of the support member <NUM> in the tire width direction, may be used to secure a securing member described below. Details of the securing member will be described later.

The support member <NUM> may be constituted of a single annular member or as a plurality of divided members that form an annular shape in their entirety. In such a case, the support members <NUM> may be disposed so as to contact each other at their ends in the circumferential direction, or may be arranged with leaving appropriate clearances. In a case in which the support member <NUM> is constituted of the plurality of divided members, each member has, for example, the shape of a sector.

In the present embodiment, over the entire circumference of the first rim member <NUM>, one of the latch portions <NUM> (more specifically, the bent portions 203b) of each of the body springs <NUM> is engaged in the engagement receiving portion <NUM> of the first rim member <NUM>, and the support member <NUM> is secured to the first rim member <NUM>, in the above-described aspect. In this manner, the latch portions <NUM> are latched on the first rim member <NUM>. In a similar manner, over the entire circumference of the second rim member <NUM>, the other latch portion <NUM> (more specifically, the bent portion 203b) of each of the body springs <NUM> is engaged in an engagement receiving portion of the second rim member <NUM>, and the support member <NUM> is secured to the second rim member <NUM>. In this manner, the latch portions <NUM> are latched on the second rim member <NUM>. In the present embodiment, one and the other latch portions <NUM> of one body spring <NUM> may be engaged, in the first rim member <NUM> and the second rim member <NUM>, in the engagement receiving portions that are positioned on a straight line in an axial direction of the first rim member <NUM> and the second rim member <NUM>. In other words, in the present embodiment, two latch portions <NUM> of one body spring <NUM> may be secured to the first rim member <NUM> and the second rim member <NUM> at the same position with respect to the circumferential direction. Therefore, the body spring <NUM> extends in a direction parallel to the axial direction of the wheel portion <NUM> and a direction orthogonal to the circumferential direction of the wheel portion <NUM>. However, the two latch portions <NUM> of the one body spring <NUM> may not necessarily be secured at the same position in the circumferential direction, with respect to the first rim member <NUM> and the second rim member <NUM>.

The number and intervals of the body springs <NUM> to be engaged in the first rim member <NUM> and the second rim member <NUM> may be determined as appropriate according to the size and weight of the tire <NUM>, required properties of the grounding deformable portion <NUM>, and the like. The number and intervals of the bolts <NUM> used to attach the support members <NUM> to the first rim member <NUM> and the second rim member <NUM> may also be determined as appropriate. For example, the bolt <NUM> does not necessarily have to be attached to every space between two of the engagement receiving portions <NUM> adjacent in the circumferential direction as in the present embodiment.

In the skeleton portion <NUM> of the tire <NUM>, the plurality of body springs <NUM>, which are engaged in the wheel portion <NUM> in this manner, are interlinked with the interlink springs <NUM> to form the grounding deformable portion <NUM>. In other words, in the present embodiment, the interlink spring <NUM> functions as an interlink member to interlink the adjacent body springs <NUM>. <FIG> is a schematic diagram illustrating an example of the interlink spring <NUM> composing the grounding deformable portion <NUM> of <FIG>. In the present embodiment, as illustrated in <FIG>, the interlink spring <NUM> has an elastic deformable portion <NUM> and a limitation portion <NUM>. Specifically, the interlink spring <NUM> is disposed between the two body springs <NUM> adjacent in the circumferential direction, which are engaged in the wheel portion <NUM>, and is interlaced with the two body springs <NUM> so as to be interlinked with the body springs <NUM>.

In the present embodiment, the elastic deformable portion <NUM> is constituted of a coil spring. The elastic deformable portion <NUM> that is made of a suitable material and has appropriate elasticity can be used according to the size and weight of the tire <NUM>, required properties of the grounding deformable portion <NUM>, and the like. It is preferable that the diameter of the coil spring constituting the elastic deformable portion <NUM> is close to the diameter of the coil spring constituting the elastic deformable portion <NUM> of the body spring <NUM>. Here, the diameter of the coil spring is the diameter of a circumscribed circle in the case of viewing the coil spring from an axial direction, and the same applies hereinafter. The closer the diameter of the coil spring constituting the elastic deformable portion <NUM> is to the diameter of the coil spring constituting the elastic deformable portion <NUM> of the body spring <NUM>, the more evenly force is applied to the grounding deformable portion <NUM> that is formed by interlinking the coil springs constituting the elastic deformable portions <NUM> with the coil springs constituting the elastic deformable portions <NUM> as described below. For example, both the diameter of the coil spring constituting the elastic deformable portion <NUM> and the diameter of the coil spring constituting the elastic deformable portion <NUM> can be <NUM> to <NUM>, e.g. <NUM> or the like.

In the present embodiment, the limitation portion <NUM> is provided at one end of the elastic deformable portion <NUM>. No other mechanism is provided at the other end of the elastic deformable portion <NUM> where the limitation portion <NUM> is not provided, and thus the elastic deformable portion <NUM> has an open shape at the other end. The limitation portion <NUM> limits displacement of the interlink spring <NUM>, which is to be interlinked with the body springs <NUM>, with respect to the body springs <NUM>. The limitation portion <NUM> limits displacement of the interlink spring <NUM> in at least one direction relative to the body springs <NUM>. In this way, by limiting displacement of the interlink spring <NUM> relative to the body springs <NUM> by the limitation portion <NUM>, in interlinking the interlink spring <NUM> with the body springs <NUM>, as described with reference to <FIG> and <FIG> below, the interlinked position of the interlink spring <NUM> is determined and secured. That is, an interlinked state of the interlink spring <NUM> with respect to the body springs <NUM> is positioned and secured. The limitation portion <NUM> has a different shape from the elastic deformable portion <NUM>. That is, in the present embodiment, the limitation portion <NUM> has a different shape from a coil shape.

In the present embodiment, the limitation portion <NUM> is constituted of a member integral with the elastic deformable portion <NUM>. That is, in the present embodiment, as illustrated in <FIG>, for example, a material of the elastic deformable portion <NUM> extends from one end of the elastic deformable portion <NUM> to form the limitation portion <NUM>. In an example illustrated in <FIG>, the limitation portion <NUM> has a ring-shaped portion formed with a wire, which forms the elastic deformable portion <NUM>, being bent into a ring shape. The ring-shaped portion is formed so as to have a central axis in a direction intersecting the direction of an axis A of the elastic deformable portion <NUM>. The ring-shaped portion of the limitation portion <NUM> may be of any size capable of limiting displacement of the interlink spring <NUM>. For example, the ring-shaped portion of the limitation portion <NUM> may be configured to have a diameter of <NUM> to <NUM> times the diameter of the elastic deformable portion <NUM>.

Here, the function of the limitation portion <NUM> will be described together with a method for interlinking the interlink spring <NUM> with the body springs <NUM>. <FIG> and <FIG> are schematic diagrams for explaining an example of the method for interlinking the interlink spring <NUM> with the body springs <NUM>.

As illustrated in <FIG>, the interlink spring <NUM> is interlinked with the two adjacent body springs <NUM> by hooking the elastic deformable portion <NUM> on the elastic deformable portions <NUM> of the body springs <NUM>, which are engaged in the wheel portion <NUM>, in such a manner as to be interlaced with the two adjacent body springs <NUM>. Specifically, the interlink spring <NUM> is interlinked with the body springs <NUM> so as to restrict the relative displacement between the two body springs <NUM> adjacent in the circumferential direction. At this time, the interlink spring <NUM> is gradually interlaced with the two adjacent body springs <NUM> by being inserted into the body springs <NUM> in such a manner as to move forward while rotating, from the side of the other end on which the limitation portion <NUM> is not provided.

As the entire elastic deformable portion <NUM> of the interlink spring <NUM> is interlaced with the body springs <NUM>, as illustrated in <FIG>, the limitation portion <NUM> eventually comes into contact with the body spring <NUM>. The limitation portion <NUM>, due to its shape, cannot be interlaced with the body springs <NUM>. Therefore, the interlink spring <NUM> does not move in an insertion direction beyond the position at which the limitation portion <NUM> contacts the body spring <NUM>. In particular, the interlink spring <NUM> does not move forward (move in the insertion direction) after the ring-shaped portion of the limitation portion <NUM> contacts the body spring <NUM>, even if the interlink spring <NUM> is attempted to be moved forward while being rotated. Thus, the limitation portion <NUM> limits displacement of the interlink spring <NUM> in at least one direction relative to the body springs <NUM>. In this manner, the limitation portion <NUM> positions and secures an interlinked state of the interlink spring <NUM> with respect to the body springs <NUM>. In addition, the interlink spring <NUM> interlinked with the body springs <NUM> is prevented from coming off from the body springs <NUM>.

It is preferable that at least one of the two ends of the interlink spring <NUM> is not secured to the wheel portion <NUM>. In the present embodiment, neither of the ends of the interlink spring <NUM> is secured to the wheel portion <NUM>. In other words, in the present embodiment, the interlink spring <NUM> is not secured at either end. However, only one of the ends of the interlink spring <NUM> may be secured to the wheel portion <NUM>. In this case, the other end of the interlink spring <NUM>, which is opposite to the one end of the interlink spring <NUM> on which the limitation portion <NUM> is provided, is secured to the rim member.

In the present embodiment, all the body springs <NUM>, which are engaged in the wheel portion <NUM>, are interlinked with the interlink springs <NUM> each disposed between the two adjacent body springs <NUM>. In the present embodiment, the skeleton portion <NUM> is configured in this manner. In other words, in the present embodiment, every body spring <NUM> of the grounding deformable portion <NUM> of the skeleton portion <NUM> is interlinked with the two interlink springs <NUM>, and every interlink spring <NUM> of the grounding deformable portion <NUM> of the skeleton portion <NUM> is interlinked with the two body springs <NUM>. Accordingly, the interlink springs <NUM> are each interlinked between the two adjacent body springs <NUM>, so even in the case of applying a load to the skeleton portion <NUM>, the distance between the body springs <NUM> does not widen too much, and function as the tire <NUM> can be easily maintained.

The interlink spring <NUM> that joins the two body springs <NUM> can be inserted from the side of the first rim member <NUM> or from the side of the second rim member <NUM> in the axial direction of the wheel portion <NUM> (i.e. the direction of a rotational axis of the tire <NUM>). It is preferable that half of the plurality of interlink springs <NUM> in the skeleton portion <NUM> are inserted from the side of the first rim member <NUM>, and the other half thereof are inserted from the side of the second rim member <NUM>. This means that the limitation portions <NUM> of the interlink springs <NUM> are evenly arranged on both sides in the axial direction of the skeleton portion <NUM>, thus easily striking a balance of the skeleton portion <NUM> and preventing the limitation portions <NUM> from being congested in only one direction in the axial direction of the skeleton portion <NUM>. In particular, the plurality of interlink springs <NUM> are more preferably inserted such that the interlink springs <NUM> that are adjacent to each other in a circumferential direction of the grounding deformable portion <NUM> are inserted from different directions. This further facilitates striking a balance of the skeleton portion <NUM>.

The skeleton portion <NUM> may also be provided with a connection member that connects the ring-shaped portions of the limitation portions <NUM> of the plurality of interlink springs <NUM>. The connection member is constituted of a wire, for example. For example, suppose that half of the plurality of interlink springs <NUM> are inserted from the side of the first rim member <NUM> and the other half thereof are inserted from the side of the second rim member <NUM>. In this case, the limitation portions <NUM> of the interlink springs <NUM> inserted from the side of the first rim member <NUM> are located on the side of the first rim member <NUM>, and the limitation portions <NUM> of the interlink springs <NUM> inserted from the side of the second rim member <NUM> are located on the side of the second rim member <NUM>. In this case, the skeleton portion <NUM> may have two wires, that is, a wire for connecting the ring-shaped portions of the plurality of limitation portions <NUM> located on the side of the first rim member <NUM> and a wire for connecting the ring-shaped portions of the plurality of limitation portions <NUM> located on the side of the second rim member <NUM>. The wire for connecting the ring-shaped portions of the plurality of limitation portions <NUM> located on the side of the first rim member <NUM> is provided, for example, along the circumferential direction of the wheel portion <NUM> so as to pass through central portions (openings formed by the ring-shaped portions) of all the ring-shaped portions of the plurality of limitation portions <NUM> located on the side of the first rim member <NUM>. Similarly, the wire for connecting the ring-shaped portions of the plurality of limitation portions <NUM> located on the side of the second rim member <NUM> is provided, for example, along the circumferential direction of the wheel portion <NUM> so as to pass through central portions of all the ring-shaped portions of the plurality of limitation portions <NUM> located on the side of the second rim member <NUM>. Such a wire is formed in a circular shape, for example, and therefore can connect the ring-shaped portions of the limitation portions <NUM> by passing through the central portions of the ring-shaped portions of the limitation portions <NUM>. Thus, the provision of the wires, which pass through the ring-shaped portions of the plurality of limitation portions <NUM>, limits displacement of the relative positions of the limitation portions <NUM>. As a result, the interlink springs <NUM> that are interlinked with the body springs <NUM> are further prevented from coming off from the body springs <NUM>.

However, the connection member for connecting the ring-shaped portions of the plurality of limitation portions <NUM> of the plurality of interlink springs <NUM> need not necessarily be configured to pass through the ring-shaped portions of the plurality of limitation portions <NUM> as described above, and the limitation portions <NUM> may be connected to each other by any form. In this case, for example, the connection member may be secured to each of the ring-shaped portions of the plurality of limitation portions <NUM> to be connected, thereby connecting the ring-shaped portions of the plurality of limitation portions <NUM>. By providing at least the wire for connecting the limitation portions <NUM> of the plurality of interlink springs <NUM>, displacement of the relative positional relationship between the interlink springs <NUM> connected by the wire is limited.

In the above embodiment, it is described that the limitation portion <NUM> is formed in a ring shape having a central axis in a direction intersecting the direction of the axis A of the elastic deformable portion <NUM>, but the shape of the limitation portion <NUM> is not limited thereto. The limitation portion <NUM> may have any configuration capable of limiting displacement of the interlink spring <NUM> in at least one direction relative to the body springs <NUM>.

In the above embodiment, it is described that the limitation portion <NUM> is constituted of a member integral with the elastic deformable portion <NUM>, but the limitation portion <NUM> does not necessarily have to be constituted of a member integral with the elastic deformable portion <NUM>. For example, as schematically illustrated in <FIG>, a limitation portion <NUM> that is constituted of a member different from and independent of the interlink spring <NUM> may limit displacement of the interlink spring <NUM> relative to the body spring <NUM>. In the example illustrated in <FIG>, the limitation portion <NUM> is configured as a member different from and independent of the interlink spring <NUM>, for limiting displacement of a contact point between the body spring <NUM> and the interlink spring <NUM> that are interlaced with each other.

The length of the interlink spring <NUM> may be determined in appropriate according to the size and weight of the tire <NUM>, the required properties of the grounding deformable portion <NUM>, and the like. The interlink spring <NUM> is preferably configured to have the elastic deformable portion <NUM> that is shorter than the length of the elastic deformable portion <NUM> of the body spring <NUM>. The interlink spring <NUM> preferably has a length such that the elastic deformable portion <NUM> extends over the entirety in the tire width direction. Thereby, the elastic deformable portions <NUM> of the body springs <NUM> are interlinked with the elastic deformable portions <NUM> of the interlink springs <NUM> in at least a grounding area.

The tire <NUM> is configured to have tread members mounted on the outer periphery of the above-described skeleton portion <NUM>. As illustrated in <FIG>, for example, the tread members are mounted on the skeleton portion <NUM> so as to extend over the entire skeleton portion <NUM> in tire width direction. The tread members are mounted at least on a grounding area, which is formed by the body springs <NUM> and the interlink springs <NUM>, of the skeleton portion <NUM>. The tread member may be configured to include, for example, a nonwoven fabric. The nonwoven fabric may be made of metal, for example. The use of the metallic nonwoven fabric enables the tire <NUM> to be used as desired in an environment where temperature largely varies. Here, description is made, supposing that the tread members are configured to include the metallic nonwoven fabric.

<FIG> and <FIG> illustrates a state in which tread members <NUM> are mounted on part of the skeleton portion <NUM>. More specifically, <FIG> is a diagram of the skeleton portion <NUM> on part of which the tread members <NUM> are mounted, viewed from outside in a radial direction of the grounding deformable portion <NUM> of the skeleton portion <NUM>, and <FIG> is an enlarged diagram of part of the skeleton portion <NUM> on part of which the tread members <NUM> are mounted.

As illustrated in <FIG> and <FIG>, grooves <NUM> are formed in the skeleton portion <NUM> with the body springs <NUM> and the interlink springs <NUM> interlaced with each other. As described above, in the present embodiment, the body springs <NUM> extend in the direction parallel to the axial direction of the wheel portion <NUM> and the direction orthogonal to the circumferential direction of the wheel portion <NUM>. Therefore, the interlink springs <NUM> interwoven with the body springs <NUM> also extend in the direction parallel to the axial direction of the wheel portion <NUM> and the direction orthogonal to the circumferential direction of the wheel portion <NUM>. Thus, in a case in which the body springs <NUM> and the interlink springs <NUM> extend in the direction parallel to the axial direction, as illustrated in <FIG> and <FIG>, the grooves <NUM> are formed so as to extend in a direction intersecting with the axial direction and the circumferential direction of the wheel portion <NUM>.

In the present embodiment, as illustrated in <FIG> and <FIG>, the tread members <NUM> are mounted in grooves <NUM> formed with the body springs <NUM> and the interlink springs <NUM>. At this time, as illustrated in <FIG>, for example, the tread member <NUM> is mounted in such a manner that at least part of the tread member <NUM> is embedded in the groove <NUM>. By mounting the tread member <NUM> in such a manner that at least part of the tread member <NUM> is embedded in the groove <NUM>, the tread member <NUM> is prevented from falling out of the groove <NUM>. In the present embodiment, only part of the tread member <NUM>, that is, only a lower portion of the tread member <NUM> on an inner side in the radial direction is mounted so as to be embedded in the groove <NUM>, and an upper portion of the tread member <NUM> on an outer side in the radial direction is exposed from the groove <NUM>. In this case, vibrations and the like during driving can be suppressed. However, the tread member <NUM> may be mounted in such a manner that its entirety is embedded in the groove <NUM>. In this case, the tread member <NUM> is prevented from falling out of the groove <NUM>. In the present embodiment, as illustrated in <FIG>, the tread members <NUM> are configured to be embedded in all the grooves <NUM> formed in the skeleton portion <NUM> and contact each other in the circumferential direction. However, the tread members <NUM> do not have to be embedded in all the grooves <NUM>. For example, the tread members <NUM> may be embedded in only some of the grooves <NUM> formed in the skeleton portion <NUM>.

In the present embodiment, it is preferable that the tread members <NUM> are detachably mounted on the skeleton portion <NUM>. By detachably mounting the tread members <NUM> on the skeleton portion <NUM>, the tread members <NUM> can be removed from the skeleton portion <NUM> and replaced, in a case in which the tread members <NUM> are worn out or the like.

In the present embodiment, as schematically illustrated in <FIG>, for example, the tread member <NUM> is made of a nonwoven fabric <NUM>. The tread member <NUM> can be configured in the shape of a rod having a through hole 300a in its central portion in cross section in an extending direction. The tread member <NUM> can be made of the nonwoven fabric <NUM> in the shape of an elongated rod the cross section of which is approximately a circle. Here, the approximate circle includes not only a perfect circle but also a distorted circle (e.g., an ellipse as schematically illustrated in <FIG>) or a shape having irregularities in a circumference in cross section. The through hole 300a provided in the tread member <NUM> is a hole for passing a core material <NUM> therethrough. The core material <NUM> extends along the extending direction of the tread member <NUM>. The core material <NUM> can be constituted of, for example, a coil spring having a fine wire diameter with a dense pitch.

The tread member <NUM> is not limited to the example illustrated in <FIG>. For example, as illustrated in <FIG>, the tread member <NUM> may be provided with a reinforcement member <NUM> for reinforcing the through hole 300a. The reinforcement member <NUM> is formed in a cylindrical shape. The reinforcement member <NUM> may be constituted of, for example, a coil spring with a dense pitch. The core material <NUM> is disposed inside the cylindrical reinforcement member <NUM>. The provision of the reinforcement member <NUM> can prevent the core material <NUM> from biting into the nonwoven fabric <NUM>, as compared with a case in which the reinforcement member <NUM> is not provided. In addition, the reinforcement member <NUM> protects the core material <NUM>, thereby improving durability of the tread member <NUM>. In addition, the reinforcement member <NUM> can store and retain heat transmitted from the wheel portion <NUM> and the like and heat emitted by the tread member <NUM>, thereby preventing supercooling of the tread member <NUM> in an extremely low temperature environment.

The tread member <NUM> may have a gourd shape in cross section, as illustrated in <FIG>, for example. In this case, the tread member <NUM> has a secured area A1 to be embedded in the groove <NUM> and a grounding area A2 to be grounded. The grounding area A2 is provided outside the secured area A1 in the radial direction of the tire <NUM>. In the tread member <NUM>, a through hole 300a is provided in the secured area A1, and a reinforcement member <NUM> is provided in the through hole 300a. A core material <NUM> is disposed inside the reinforcement member <NUM>. In cross section, the width of the grounding area A2 is larger than the width of the secured area A1. Also, the length of the grounding area A2 in the radial direction of the tire <NUM> is longer than the length of the secured area A1 in the radial direction of the tire <NUM>.

In the present embodiment, the tread member <NUM> is preferably further provided with a securing member for securing the tread member <NUM> to the skeleton portion <NUM>. This further prevents the tread member <NUM> from falling off from the skeleton portion <NUM>.

For example, in a case in which the tread member <NUM> is configured in the rod shape, as in the example illustrated in <FIG>, the tread member <NUM> may be provided with securing members extending from both ends of the rod-shaped tread member <NUM> in the extending direction of the tread member <NUM>. For example, the tread member <NUM> may be provided with securing members extending in an extending direction of the core material <NUM>. In this case, the core material <NUM> and the securing members may be configured as an integral member. Specifically, a coil spring having functions as the core material <NUM> and the securing members is inserted into the through hole 300a and is secured to the skeleton portion <NUM>, thereby securing the tread member <NUM> to the skeleton portion <NUM>. At least one coil spring is used, and a plurality of coil springs may be used.

The securing member has, for example, a mechanism capable of being secured to the wheel portion <NUM>. As one specific example, as illustrated in <FIG>, for example, a securing member <NUM> has a mechanism capable of being secured to the threaded end of the bolt <NUM> protruding inside the wheel portion <NUM>, and can be secured to the wheel portion <NUM> by securing the mechanism to the threaded end of the bolt <NUM>. In this case, the securing member <NUM> includes, as illustrated in <FIG>, a secured portion <NUM> that is secured to the threaded end of the bolt <NUM> and a joint portion <NUM> that joins between the above-described core material <NUM> (omitted in the drawing) and the secured portion <NUM>. The joint portion <NUM> is constituted of a coil spring, for example.

In the above example, the reinforcement member <NUM> is preferably made of a coil spring whose wire diameter of strands is thinner than that of the joint portion <NUM> of the securing member <NUM> and whose pitch is denser. The strands of the joint portion <NUM> preferably have a wire diameter of <NUM> or more, for example. A helical angle of the joint portion <NUM> is preferably from <NUM>° to <NUM>°. This facilitates moderate absorption of a load on the tread member <NUM>, while maintaining a joint state between the secured portion <NUM> and the core material <NUM>.

The tire <NUM> is preferably further provided with a retainer to maintain a mounted state of the tread member <NUM> on the skeleton portion <NUM>. This further prevents the tread member <NUM> from falling off from the skeleton portion <NUM>.

A retainer <NUM> may be a member that is formed in the shape of an elongated strip, as illustrated in <FIG>, for example, and that can be secured in an annular shape by joining and securing its ends together, as illustrated in <FIG>, for example. By securing the retainer <NUM> in the annular shape in a state of integrating the tread member <NUM> and the body springs <NUM> and/or the interlink springs <NUM>, as illustrated in <FIG> and <FIG>, the tread member <NUM> can be secured to the grounding deformable portion <NUM> (the body springs <NUM> and/or the interlink springs <NUM>). The mounted state of the tread member <NUM> on the skeleton portion <NUM> (more specifically, the body springs <NUM> and/or the interlink springs <NUM> in the present embodiment) can be maintained by retaining the tread member <NUM> at one or more points per tread member <NUM> by one or more retainers <NUM>. An aspect of the retainer <NUM> is not limited thereto, and the retainer <NUM> may have any aspect that can maintain the mounted state of the tread member <NUM> on the skeleton portion <NUM>.

As described above, the tire <NUM> is provided with the tread member <NUM> disposed at least on the outer periphery of the skeleton portion <NUM>. Therefore, even in a case in which the tire <NUM> is used on, for example, sandy ground or the like, the tread member <NUM> can prevent foreign matter such as sand from entering the interior (that is, the side of the center of rotation) of the tire <NUM>. This serves to prevent deterioration in running performance of the tire <NUM>.

Thus, according to the tire <NUM>, each of the plurality of body springs <NUM>, which configure the grounding deformable portion <NUM>, has the elastic deformable portion <NUM> and the latch portions <NUM> that are provided at both ends of the elastic deformable portion <NUM> and have a shape different from the elastic deformable portion <NUM>. The latch portions <NUM> are latched on the first rim member <NUM> and the second rim member <NUM>. Accordingly, the body springs <NUM> can be reliably joined to the first rim member <NUM> and the second rim member <NUM>. This effect, for example, makes it difficult for the body springs <NUM> to come off from the first rim member <NUM> and the second rim member <NUM>, even if the tire <NUM> is used in a special environment. Also, for example, if the elastic deformable portions <NUM> of the body springs <NUM> are directly joined to the first rim member <NUM> and the second rim member <NUM>, the elastic deformable portions <NUM> may easily fall off from the first rim member <NUM> and the second rim member <NUM>, depending on a method of joining or due to the wearing away of the elastic deformable portions <NUM>. In contrast to this, in the present embodiment, such a fear is less likely to occur because the latch portions <NUM> of a different shape from the elastic deformable portions <NUM> are latched. Furthermore, even in a case in which the tire <NUM> is used, for example, on a lunar surface where temperature largely varies, the body springs <NUM> are engaged in the engagement receiving portions <NUM> of the first rim member <NUM> and the second rim member <NUM>, so the occurrence of thermal expansion or thermal contraction in the first and second rim members <NUM> and <NUM> or the body springs <NUM> does not cause the body springs <NUM> to come off from the first rim member <NUM> and the second rim member <NUM>, thus facilitating maintaining the form and function of the tire <NUM>.

In addition, in a case in which the first rim member <NUM> and the second rim member <NUM> have the engagement receiving portions <NUM>, and the latch portions <NUM> of the body springs <NUM> are latched on the engagement receiving portions <NUM>, as in the present embodiment, the body springs <NUM> can be more reliably joined to the first rim member <NUM> and the second rim member <NUM>.

In addition, in a case in which a latched state of the latch portions <NUM> is maintained using the support members <NUM>, as in the present embodiment, the body springs <NUM> are further prevented from coming off from the first rim member <NUM> and the second rim member <NUM>. Therefore, the plurality of body springs <NUM> can be more reliably engaged in the engagement receiving portions <NUM> of the first rim member <NUM> and the second rim member <NUM>.

In the above embodiment, it is described that the latch portions <NUM> of the body spring <NUM> is configured to each include the straight portion 203a and the bent portion 203b disposed at the tip end of the straight portion 203a. However, the configuration of the latch portions <NUM> is not necessarily limited thereto. The latch portions <NUM> may have any shape that is different from the shape of the elastic deformable portion <NUM> and is capable of being latched on the first rim member <NUM> and the second rim member <NUM>. The engagement receiving portions <NUM> of the first rim member <NUM> and the second rim member <NUM> may also have any configuration, corresponding to the configuration of the latch portions <NUM>. For example, the latch portions <NUM> may be formed in a linear shape. In this case, the first rim member <NUM> and the second rim member <NUM> may be provided with engagement receiving portions in which the linear latch portions <NUM> can be engaged, or the latch portions <NUM> may simply be secured by the support members <NUM>.

The latch portions <NUM> are not limited to the examples described herein, and may have any configuration capable of latching the body spring <NUM> on the first rim member <NUM> and the second rim member <NUM>. For example, the latch portions <NUM> may be each formed in a hook shape.

For example, in the above embodiment, it is described that the bent portion 203b of the latch portion <NUM> of the body spring <NUM> is bent orthogonally to the straight portion 203a. However, the bent portion 203b does not necessarily have to be orthogonal to the straight portion 203a. The bent portion 203b may be bent at a predetermined angle with respect to the straight portion 203a. In this case, the engagement receiving portion <NUM> may be formed as a hole provided in a direction that matches the angle of bending of the bent portion 203b.

As illustrated in <FIG>, the latch portion <NUM> of the body spring <NUM> may be configured to include, for example, a straight portion 203a and a ring portion 203c disposed at a tip end of the straight portion 203a. The ring portion 203c is formed in an annular shape having a through hole 203d in its center. In this case, the engagement receiving portion <NUM> may be configured to be, for example, a projection that can penetrate the through hole 203d. In this case, by penetrating the projection of the engagement receiving portion <NUM> through the through hole 203d of the ring portion 203c of the latch portion <NUM>, the latch portion <NUM> can be latched on the engagement receiving portion <NUM>.

In the above embodiment, it is described that the elastic deformable portion <NUM> of the body spring <NUM> and the elastic deformable portion <NUM> of the interlink spring <NUM> are each constituted of a coil spring. However, the elastic deformable portion <NUM> of the body spring <NUM> and the elastic deformable portion <NUM> of the interlink spring <NUM> do not necessarily have to be constituted of a coil spring. For example, as illustrated in <FIG>, the elastic deformable portion <NUM> of the body spring <NUM> and/or the elastic deformable portion <NUM> of the interlink spring <NUM> may be each configured to include a two-dimensional (i.e., extending along approximately the same plane) corrugated metal member, instead of a coil spring. <FIG> illustrates an example of a case in which the elastic deformable portions <NUM> and the elastic deformable portions <NUM> are each formed in a two-dimensional corrugated shape. The corrugated metal member may be, for example, in the shape of a linked semicircle or a sinusoidal waveform. Even in this case, the body springs <NUM> and the interlink springs <NUM> can be interlinked by interlacing the corrugated metal members.

In the above-described embodiment, it is described that the tread member <NUM> is configured include the metallic nonwoven fabric, but the material of the tread member <NUM> is not limited to the metallic nonwoven fabric. For example, the tread member <NUM> may be made of silicon rubber. In this case, the cushioning property and the wear resistance of the tread member <NUM> are improved. In addition, the traction performance of the tire <NUM>, in running on sandy ground or the like, is improved.

For example, the tread member <NUM> may be made of rubber. For example, the tread member <NUM> may be made of natural rubber (NR) and synthetic rubber. As the synthetic rubber, there are, for example, butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), butyl rubber (IIR), butyl halide rubber, chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), and the like. One type of the rubber may be used alone, and two or more types may be used in combination.

The rubber tread member <NUM> may be formed in the shape of a rod, as described in the above embodiment, or may be molded in another shape. <FIG> is an external perspective view of an example of a rubber tread <NUM> that is molded in a different shape from a rod. The rubber tread <NUM> has, for example, as illustrated in <FIG>, a flat plate shaped body <NUM> and protruding portions <NUM> that project from the body <NUM>. For example, a plurality of the rubber treads <NUM> as illustrated in <FIG> are attached to the outer periphery of the grounding deformable portion <NUM>, so the entire outer periphery of the grounding deformable portion <NUM> is covered with the plurality of the rubber treads <NUM>. The protruding portions <NUM> are configured in such a shape that can be embedded in the grooves <NUM> formed by the body springs <NUM> and the interlink springs <NUM>. By embedding the protruding portions <NUM> in the grooves <NUM>, the rubber tread <NUM> can be attached to the outer periphery of the grounding deformable portion <NUM>. Each of the protruding portions <NUM> is provided with a through hole 322a for penetrating a core material having a function similar to that of the core material <NUM> described above. The rubber tread <NUM> can improve gription in the tread member <NUM>.

In the above embodiment, it is described that the body springs <NUM> and the interlink springs <NUM> extend in the direction parallel to the axial direction, and the grooves <NUM> are formed so as to extend in an intersecting direction with respect to the axial direction and the circumferential direction of the wheel portion <NUM>. However, the body springs <NUM> and the interlink springs <NUM> do not necessarily have to extend in the direction parallel to the axial direction. For example, the body springs <NUM> and the interlink springs <NUM> may extend in a direction intersecting the axial direction. In this case, the grooves <NUM> may extend in a direction along the circumferential direction of the grounding deformable portion <NUM> or in a direction orthogonal to the circumferential direction of the grounding deformable portion <NUM>. The tread members <NUM> may be mounted on the grounding deformable portion <NUM> in such a manner that at least part of the tread members <NUM> are embedded in the grooves <NUM>, regardless of the direction to which the grooves <NUM> extend.

Claim 1:
A tire (<NUM>) comprising:
a skeleton portion (<NUM>) including a rim member, a plurality of body springs (<NUM>) latched on the rim member, and a plurality of interlink springs (<NUM>) interlaced with the body springs (<NUM>); and
a plurality of tread members (<NUM>) disposed at least on an outer periphery of the skeleton portion (<NUM>);
wherein each of the plurality of tread members (<NUM>) is mounted on a groove (<NUM>) formed with the body springs (<NUM>) and the interlink springs (<NUM>), in such a manner that at least part of each of the plurality of tread members (<NUM>) is embedded in the groove (<NUM>);
wherein each of the tread members (<NUM>) is configured to include a metallic nonwoven fabric (<NUM>);
wherein each of the tread members (<NUM>) is configured to be in a shape of a rod having a through hole (300a) in its central portion in cross section in an extending direction.