Airless tire

Abstract

Disclosed is an airless tire fastened to a rim. The airless tire comprises: a ground portion, at least portion of which is in contact with the ground when the tire rotates, and which has a predetermined width and extends along the circumference of the tire; a fastening portion fastened to the rim; a side portion extending from both sides of the ground portion to the fastening portion along the surface of the tire; and a plurality of side grooves radially arranged with respect to the center of rotation of the tire and recessed in the side portion. Therefore, the airless tire has low rolling resistance due to light weight, is advantageous in terms of heat dissipation by increasing the surface area, and can reduce air resistance by improving the flow of air flowing along the side surface of the tire during driving.

Description

airless tires

[0001] This article is about airless tires.

[0002] This institute received support from the Ministry of Trade, Industry and Energy's 'Leisure Equipment Industry Development Support' project, 'Airless tire for electric mobility under 45W rolling resistance to maximize energy efficiency by improving rolling, stability, and heat resistance' (Project No.: 2022-1-025 / Announcement No.: No. 2022-234 / Name of specialized organization: Korea SMEs and Startups Agency / Research and development period: June 23, 2022 - June 22, 2023).

[0003] Generally, airless tires for bicycles are a type of tire designed to solve the problem of tires getting punctured. Instead of putting an air-filled tube inside the tire, they fill the inside of the tire with a material such as rubber, or apply a structure that includes spokes that disperse shock from the ground and are connected to the rim of the bicycle wheel, so that the tire does not lose air even if it is punctured or pressed by an external object.

[0004] While using airless tires like these can prevent punctures in bicycle wheels, they also increase tire weight, reducing overall tire performance and reducing rolling resistance. Rolling resistance is the resistance exerted when a circular object, such as a tire, rolls on a surface, primarily caused by tire deformation or friction with the ground. Typically, a tire's rolling resistance is lower than its kinetic friction, but the higher the rolling resistance, the more energy is required to overcome the resistance.

[0005] Therefore, an airless tire is required that reduces rolling resistance by lowering the weight of the tire, minimizes air resistance acting on the tire surface when the tire rotates, and improves heat dissipation performance by increasing the tire surface area.

[0006] The present invention is intended to solve the problems of the prior art described above, and the present invention provides an airless tire having a ground contact portion that is in contact with the ground at least partially when the tire rotates, has a predetermined width, and extends along the circumference of the tire; a fastening portion that is fastened to the rim; side portions that are formed to extend along the surface of the tire from both sides of the ground contact portion to the fastening portion; and a plurality of side grooves that are radially arranged based on the rotation center of the tire and are formed into the side portions, thereby reducing the weight and lowering the rolling resistance, and increasing the surface area and thus being advantageous in terms of heat dissipation.

[0007] In addition, the present invention aims to provide an airless tire with reduced air resistance by improving the air flow along the side of the tire during driving by extending the side groove from one end formed on the circumference side of the cross-sectional center of the tire to the other end formed on the rotational center side of the cross-sectional center.

[0008] In addition, the side groove of the present invention aims to provide an airless tire with improved air flow by changing the length and depth formed on the tire to allow smooth air flow along the side of the tire.

[0009] In addition, the side groove of the present invention is intended to provide an airless tire in which the inner wall is formed in a curved shape on the side surface of the tire, so that air on the front side of the tire flows naturally to the rear side along the inner wall of the side groove.

[0010] In addition, the present invention aims to provide an airless tire including an outer groove formed along the circumference of the tire between the ground portion and the side portion, in which air on the front side of the tire flows to the rear side of the tire along the upper and lower directions of the tire.

[0011] However, the technical tasks that the embodiments of the present invention seek to achieve are not limited to the technical tasks described above, and other technical tasks may exist.

[0012] As a technical means for achieving the above-described technical task, an airless tire according to one embodiment of the present invention may include a ground contact portion that is in contact with the ground at least partially when the tire rotates, has a predetermined width, and extends along the circumference of the tire; a fastening portion that is fastened to the rim; side portions that are formed to extend along the surface of the tire from both sides of the ground contact portion to the fastening portion; and a plurality of side grooves that are radially arranged based on the rotation center of the tire and are recessed in the side portions.

[0013] In an airless tire according to one embodiment of the present invention, the side groove may extend along the side portion from one end formed on the circumferential side from the cross-sectional center of the tire to the other end formed on the rotational center side from the cross-sectional center.

[0014] In an airless tire according to one embodiment of the present invention, the side groove may have a burrowing depth that gradually increases as it extends along the side portion from one end of the circumferential side of the side groove toward the center of the cross-section.

[0015] In an airless tire according to one embodiment of the present invention, the side groove may extend along the side portion from a point where the side groove intersects a straight line extending parallel to the rotational axis of the tire from the center of the cross-section to the other end of the side groove on the rotational center side, so that the depth of the side groove may gradually decrease.

[0016] In an airless tire according to one embodiment of the present invention, the side groove may extend along the side portion from a point where a straight line extending parallel to the rotational axis of the tire from the cross-sectional center intersects the side groove to the other end of the side groove on the rotational center side, so that the depth of the side groove may gradually increase.

[0017] In an airless tire according to one embodiment of the present invention, the side groove includes a first segment forming an inner wall on one side of the side groove and a second segment forming an inner wall on the other side of the side groove, and at least a portion of the first segment and the second segment can be extended with different curvatures.

[0018] In an airless tire according to one embodiment of the present invention, as the side groove extends along the side portion from one end on the circumferential side to the other end on the rotation center side, the distance between the first segment and the second segment may gradually increase and then decrease.

[0019] In an airless tire according to one embodiment of the present invention, the maximum depth of penetration toward the center of the cross-section of the side groove may be 5 mm or more.

[0020] In an airless tire according to one embodiment of the present invention, the extension length of the side groove may be at least 1 / 4 of the length from the circumferential end of the grounding portion to the end of the fastening portion of the side portion.

[0021] In an airless tire according to one embodiment of the present invention, a plurality of side grooves formed on each side of the contact portion can be symmetrically formed with respect to the contact portion.

[0022] In an airless tire according to one embodiment of the present invention, a plurality of side grooves formed on each side of the contact portion can be alternately formed based on the contact portion.

[0023] In an airless tire according to one embodiment of the present invention, an outer groove formed along the circumference of the tire between the ground contact portion and the side portion may be further included.

[0024] The above-described problem-solving methods are merely exemplary and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, additional embodiments may be included in the drawings and detailed description of the invention.

[0025] According to the above-mentioned problem solving means of the present invention, the present invention is to solve the problems of the above-mentioned prior art, and the present invention provides an airless tire including a ground contact portion that is in contact with the ground at least partially when the tire rotates, has a predetermined width, and extends along the circumference of the tire; a fastening portion that is fastened to the rim; a side portion that is formed to extend along the surface of the tire from both sides of the ground contact portion to the fastening portion; and a plurality of side grooves that are radially arranged based on the rotation center of the tire and are recessed into the side portion, thereby reducing the weight and lowering the rolling resistance, and increasing the surface area and thereby being advantageous in terms of heat dissipation.

[0026] In addition, according to the above-described problem solving means of the present invention, the side groove extends along the side portion from one end formed on the circumference side at the cross-sectional center of the tire to the other end formed on the rotation center side at the cross-sectional center, thereby improving the air flow along the side of the tire during driving, thereby providing an airless tire with reduced air resistance.

[0027] In addition, according to the aforementioned means for solving the problem of the present invention, the side grooves are formed on the tire in a different length and depth, so that the air flow along the side of the tire is smooth, thereby improving the air flow.

[0028] In addition, according to the solution to the problem of the present invention described above, the side groove of the present invention has the effect of providing an airless tire in which the inner wall is formed in a curved shape on the side portion of the tire, and the air on the front side of the tire flows naturally to the rear side along the inner wall of the side groove.

[0029] In addition, according to the above-described means for solving the problem of the present invention, the present invention can provide an airless tire in which air on the front side of the tire flows to the rear side of the tire along the upper and lower directions of the tire, including an outer groove formed along the circumference of the tire between the ground contact portion and the side portion.

[0030] Figure 1 is a schematic perspective view of an airless tire according to one embodiment of the present invention.

[0031] Fig. 2 is a schematic drawing showing a cross-section AA' of an airless tire according to one embodiment of the present invention.

[0032] Figure 3 is a schematic drawing showing an enlarged cross-section of an airless tire according to one embodiment of the present invention.

[0033] Fig. 4 is a schematic drawing showing a cross-section of AA' of an airless tire according to another embodiment of the present invention.

[0034] Fig. 5 is an enlarged view of a portion of the surface of an airless tire according to one embodiment of the present invention.

[0035] Fig. 6 is a schematic drawing showing a side groove formed on a side portion of an airless tire according to one embodiment of the present invention.

[0036] Fig. 7 is a front view of an airless tire according to one embodiment of the present invention.

[0037] Fig. 8 is a front view of an airless tire according to another embodiment of the present invention.

[0038] Below, with reference to the attached drawings, embodiments of the present invention are described in detail to facilitate easy implementation by those skilled in the art. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity, and similar reference numerals have been used throughout the specification to indicate similar elements.

[0039] Throughout this specification, when a part is said to be "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "electrically connected" with another element in between.

[0040] Throughout this specification, when it is said that a member is located “on,” “above,” “upper,” “lower,” “lower” or “lower” another member, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0041] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0042] Additionally, terms related to direction or location (e.g., "upper side") in the description of the embodiments of the present invention are set based on the arrangement of each component shown in the drawings. For example, when looking at Figure 1, the 12 o'clock direction may be considered "upper side," etc.

[0043] In addition, in the description of the embodiment of the present invention, the circumferential side (12 o'clock direction in FIG. 2) can be understood to refer to the direction of the outer peripheral surface of the tire, and the rotation center side (6 o'clock direction in FIG. 2) can be understood to refer to the direction of the rotation center (X), which is the center around which the tire rotates.

[0044] The present invention relates to an airless tire that is lightweight and thus has low rolling resistance, has an increased surface area to be advantageous in terms of heat dissipation, and has improved air flow along the side of the tire during driving to reduce air resistance.

[0045] An airless tire (10) according to one embodiment of the present invention will be described. The airless tire (hereinafter referred to as "tire") may be filled with a material such as rubber or synthetic resin or may have a structure such as a shear band and a spoke. In the embodiment described herein, the tire may be a solid tire filled with rubber, synthetic resin or a material equivalent thereto. The tire is fastened to a rim, and the "fastening" of the tire and the rim may mean that the tire is seated on a portion of the rim and at least a portion of the rim and a portion of the tire are combined or connected to prevent the tire from falling off from the rim, and may include a case where a portion of the tire is accommodated in a portion of the rim or a portion of the tire is in direct contact with a portion of the rim so that the tire does not fall off from the rim, and may also include a case where a fastening unit (not shown) separately provided to fasten the tire (10) to the rim (30) is provided so that it does not fall off from the rim.

[0046] First, referring to FIGS. 1 and 2, it is preferable that the rim (30) be formed in a ring shape, and that a connecting portion be formed along a circumferential direction based on the rotation center (X) of the tire, and be fastened to at least a portion of the tire (10). The rim (30) may have a shape in which a portion is recessed so that a connecting portion (13) of the tire described later is inserted or seated, but the shape of the rim is not limited thereto, and any shape in which the tire (10) is fastened to the rim (30) and stably fixed is sufficient.

[0047] Referring to FIG. 1, the tire (10) has a side groove structure formed along the side portion of the tire and radially arranged on the surface of the tire, thereby reducing the overall weight of the tire and reducing rolling resistance, while allowing air to smoothly flow from the front side of the tire to the rear side of the tire through the side groove formed on the side portion of the tire when the tire rotates, and further increasing the surface area of ​​the tire to improve the heat generation characteristics of the tire. The tire (10) may include a contact portion (11), a side portion (12), a fastening portion (13), and a side groove (15).

[0048] The above-mentioned contact portion (11) is a portion that at least partly contacts the ground when the tire rotates, and may have a predetermined width and be formed to extend along the circumference of the tire. Although not shown, treads or protrusions may be formed on the contact portion (11) to improve driving performance, such as improved grip or anti-slip. Referring to the cross-sectional view illustrated in Fig. 2, the contact portion (11) may be formed on the circumference side of the tire (the 12 o'clock direction in Fig. 2), and may be extended symmetrically with a predetermined width based on the first axis (the 12 o'clock and 6 o'clock direction axes in Fig. 2) that passes vertically through the cross-sectional center (O) of the tire. In a normal driving environment, the contact portion (11) between the outer peripheral grooves (19) described below may be in contact with the ground. However, in an environment where a heavy load is applied, the side portion (12) beyond the outer peripheral grooves (19) may also be in contact with the ground, which is not excluded from the scope of the right.

[0049] The above-described side portion (12) is configured to extend from both sides of the ground contact portion (11) along the surface of the tire to the fastening portion (13). As described below, the fastening portion (13) can be accommodated or seated inside the rim (30) for fastening to the rim (30), so the side portion (12) may refer to a portion that is not covered by the rim (30) among the portions that extend from one end and the other end of the ground contact portion (11) along the tire surface toward the center of rotation of the tire. That is, one end of the side portion (12) may be an end or a point near the end of the ground contact portion (11), and the other end of the side portion (12) may be a portion where the surface of the tire comes into contact with one end of the rim (30).

[0050] Referring to FIG. 2, the side portion (12) may have a first point (121) as a point where a straight line extending parallel to the rotational axis of the tire from the cross-sectional center (O) of the tire intersects the side portion (12). In one embodiment, the cross-sectional center (O) may be a point that bisects the length (H) from the circumferential end of the ground contact portion to the end of the fastening portion of the side portion, and bisects the width of the tire in the left-right direction.

[0051] In one embodiment, the first point (121) may be the most protruding portion of the side portion (12) toward the left and right sides of the tire. That is, the most protruding first point (121) of the tire and the cross-sectional center (O) may be arranged on a straight line parallel to the rotation axis. However, this does not exclude the case where the first point (121) is not the most protruding portion of the side portion (12) toward the left and right sides of the tire.

[0052] The above-mentioned fastening portion (13) is a portion that is fastened to the rim (30), and at least a portion thereof is accommodated or seated within the rim (30) for fastening to the rim (30). The fastening portion (13) is formed on the rotation center side of the tire (6 o'clock direction in FIG. 2), and may have a predetermined shape, such as a surface that is curved to facilitate fastening to the rim (30) or to accommodate a fastening unit (not shown).

[0053] FIG. 2 is a cross-sectional view taken along line AA' of FIG. 1. Referring to FIGS. 1 and 2, a side groove (15) according to one embodiment of the present invention is arranged radially with respect to the rotational center of the tire, and may be formed to a predetermined depth from the side portion (12) toward the cross-sectional center (O) of the tire. The side groove (15) may extend along the side portion from one end (15a) formed on the circumferential side from the cross-sectional center (O) of the tire to the other end (15b) formed on the rotational center side from the cross-sectional center. Accordingly, the cross-sectional center (O) of the tire is located between one end of the side groove (15) on the circumferential side and the other end on the rotational center side.

[0054] The extension length (L) from one end of the side groove (15) to the other end may be at least 1 / 4 of the length (H) from the peripheral end of the contact portion (11) to the one end of the fastening portion (13) of the side portion (12). Compared to the case where the side groove is formed in a hole shape in a specific area of ​​the side portion (12), the side groove is formed along the rotational direction of the tire, thereby reducing air resistance and reducing the weight of the tire. At this time, the extension length of the side groove and the length from the peripheral end of the contact portion to the one end of the fastening portion of the side portion may be the length in the direction of the first axis passing vertically through the cross-sectional center (O). Referring to FIG. 2, as the side groove (15) is formed along the side portion from the peripheral end (15a) to the other end (15b) of the rotational center, the volume of the tire is reduced, and the thickness of the tire is reduced in the area where the side groove is formed compared to the area where the side groove is not formed. When a bicycle or the like moves forward as the tire rotates, the air at the front or circumference of the tire flows toward the rear of the tire or the center of rotation along the side groove (15). The air flows along the surface of the tire, and when the length from the circumference end of the contact part, which is the surface that the air flows against, to the end of the fastening part of the side part is H, the extended length (L) of the side groove must be a certain amount or more, preferably 1 / 4 or more, compared to the tire H, so that the air can actually flow along the side groove and have an air flow improvement effect.

[0055] Continuing with reference to FIG. 2, the side groove (15) may have different recessed depths at each point. As it extends from one end (15a) of the side groove along the side portion (12) toward the cross-sectional center, the recessed depth of the side groove may gradually increase. In addition, the side groove (15) may have an intersection point (15c) as a point where a straight line extending parallel to the rotational axis of the tire from the cross-sectional center (O) of the tire intersects the side groove. As the side groove (15) extends along the side portion from the intersection point (15c) to the other end (15b) of the side groove toward the rotational center, the recessed depth of the side groove may gradually decrease. That is, in one embodiment illustrated in FIG. 2, as the side groove (15) extends along the side portion (12) from one end (15a) on the circumferential side to the other end (15b) on the rotation center side, the burrow depth of the side groove (15) may gradually increase and then decrease. In one embodiment, the burrow depth (w1) from the first point (121) of the side portion to the intersection point (15c) of the side grooves may be maximum.

[0056] Meanwhile, as illustrated in FIG. 3, each point of the side portion (12) may be defined by a distance (ta, tb) from the first axis passing vertically through the cross-sectional center (O). In a direction parallel thereto, a recessed depth (wa, wb) at each point of the side groove (15) may also be defined. In one embodiment, the side portion (12) recessed by the side groove (15) may be formed to have a convex shape to the left and right. That is, the difference (tb-ta) between the distance (tb) from the first axis at a point on the cross-sectional center (O) side of the side portion (12) and the distance (ta) from the first axis at a point on the circumferential side may be greater than the difference (wb-wa) between the distance (wb) from the first axis at a point on the cross-sectional center side of the side groove and the distance (wb) from the first axis at a point on the circumferential side (tb-ta>wb-wa). Alternatively, the difference (tb-wb) between the distance (tb) from the first axis at a point on the cross-sectional center (O) side of the side portion (12) and the distance (wb) from the first axis at a point on the cross-sectional center (O) side of the side groove may be greater than the difference (ta-wa) between the distance (ta) from the first axis at a point on the circumference side of the side portion and the distance (wa) from the first axis at a point on the circumference side of the side groove. Accordingly, when air flows from the circumference side of the tire to the rotation center side, the air flow is improved, and excessive negative pressure can be prevented from occurring in the side portion of the tire.

[0057] The side groove (16) of another embodiment of the present invention illustrated in FIG. 4 may have different indentation depths at each point. As it extends from one end (16a) of the side groove along the side portion (12) toward the cross-sectional center, the indentation depth of the side groove may gradually increase. In addition, the side groove (16) may be provided such that as it extends along the side portion from an intersection point (16c), which is a point where a straight line extending parallel to the rotational axis of the tire from the cross-sectional center intersects the side groove, the indentation depth of the side groove gradually increases to the other end (16b) of the side groove toward the rotational center. At this time, the indentation depth of the side groove (16) may be in the direction from the side groove toward the cross-sectional center (O). That is, in one embodiment illustrated in FIG. 3, as the side groove (16) extends along the side portion (12) from one end (16a) on the circumference side to the other end (16b) on the rotation center side, the burrow depth of the side groove (16) may gradually increase. In the embodiment, the burrow depth (w3) at the other end (16b) on the rotation center side of the side groove may be greater than the burrow depth (w2) from the first point (121) of the side portion to the intersection point (16c) of the side groove.

[0058] In one embodiment, the maximum depth of the side groove (15) may be 5 mm or more. In the case of a conventional pneumatic tire including a tube inside the tire, it is difficult to form a side groove having a maximum depth of penetration like that of the present disclosure due to the thin thickness of the side portion. However, in the case of an airless tire that is formed by filling the inside with a material such as a synthetic resin or a single material, a side groove having a depth of penetration of 5 mm or more can be formed in the side portion of the tire. Through this, air resistance due to the tire shape can be minimized, and in the case of a tire according to one embodiment of the present disclosure, the drag coefficient can be reduced to 0.1 or less as shown in Table 1 below. Table 1 below shows the drag coefficient (Cd) according to the width and depth of the side groove (15) formed in the side portion (12).

[0059] Hole width (mm) Hole depth (mm) Cd Cloud resistance (W) 0 0.45 5 2 2 0.25 0.5 5 0.14 7 7 0.07 4 5

[0060] [Tire performance according to hole structure and dimensions]

[0061]

[0062] Referring to FIGS. 5 and 6, the side groove (15) may include a first segment (151) forming one inner wall of the side groove and a second segment (153) forming the other inner wall. The first segment (151) and the second segment (153) may be formed as curves extending with at least a portion having different curvatures. When the tire rotates, air on the circumferential side of the tire flows into the space between the first segment (151) and the second segment (153) and then flows toward the center of rotation along the side groove. As illustrated in FIG. 5, when the tire rotates, air first touches the circumferential side of the tire, and the first segment and the second segment may be formed so that the air smoothly flows toward the rear of the tire, i.e., toward the center of rotation, as the tire rotates. When the tire rotates downward, the first segment (151) and the second segment (153) may have an upwardly convex shape. In other words, when the tire rotates counterclockwise when viewed from one side, the first segment (151) and the second segment (153) may form a clockwise curve when extending from the circumference side of the tire (left side of FIG. 5) to the rotation center side (right side of FIG. 5).

[0063] In addition, as the side groove (15) extends along the side portion from one end (15a) on the circumferential side to the other end (15b) on the rotation center side, the distance (d) between the first segment (151) and the second segment (153) can gradually increase and then decrease.

[0064] Referring to FIG. 6, the first segment (151) and the second segment (153) may each have a first diverging portion (1511) and a second diverging portion (1531) that extend and are spaced apart from one end (15a) of the side groove. The first diverging portion (1511) and the second diverging portion (1531) may be formed from one end (15a) of the side groove to a portion where an intersection point (15c) or the first point (121) is formed, and at least a portion thereof may extend with different curvatures. At this time, the radius of curvature (r1) of a circle (c1) formed by at least a portion of the first diverging portion (1511) may be smaller than the radius of curvature (r2) of a circle (c2) formed by at least a portion of the second diverging portion (1531). Accordingly, as the side groove extends from the end (15a) to the intersection (15c), the distance (d) between the first segment and the second segment can gradually increase. The thickness (depth direction in FIG. 6) of the tire increases from the circumference side (left side in FIG. 6) of the tire toward the cross-sectional center (O), and the above shape allows air to flow smoothly along the surface of the side groove.

[0065] Referring to one embodiment of the present invention illustrated in FIG. 7, the side portions (12) are arranged on both sides of the ground portion (11), and side grooves (15) may be formed radially on the side portions (12) based on the center of rotation. At this time, a plurality of side grooves (15) formed on the side portions (12) on both sides may be formed symmetrically based on the ground portion (11).

[0066] Referring to another embodiment of the present invention illustrated in FIG. 8, a plurality of side grooves (15) formed on the side portions (12) on both sides of the ground portion (11) can be alternately formed based on the ground portion.

[0067] Referring again to FIGS. 1, 7 and 8, the tire (10) according to one embodiment of the present invention may further include an outer peripheral groove (19). The outer peripheral groove (19) may be configured to extend between the ground contact portion (11) and the side portion (12), and may be formed by being recessed along the circumference of the tire between the ground contact portion (11) and the side portion (12). The outer peripheral groove (19) may substantially divide the ground contact portion (11) and the side portion (12), and may allow air blowing from the front of the tire to flow along the outer peripheral groove (19) toward the upper and lower sides of the tire (12 o'clock and 6 o'clock directions in FIGS. 7 and 8). As the above outer groove (19) is formed, air blowing from the front of the tire flows to the left and right sides of the tire (3 o'clock and 9 o'clock directions in FIGS. 7 and 8) through the side groove (15) and also flows to the upper and lower sides of the tire, so that air flow on the tire surface can be further improved, and the surface area of ​​the tire can be further increased, so that heat generation characteristics can be improved.

[0068] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0069] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. In an airless tire attached to a rim, A contact portion that is in contact with the ground at least partially when the tire rotates, has a predetermined width, and extends along the circumference of the tire; A fastening portion connected to the above rim; A side portion extending along the surface of the tire from both sides of the ground portion to the fastening portion; and An airless tire comprising a plurality of side grooves arranged radially based on the rotation center of the tire and formed in the side portion.

2. In paragraph 1, An airless tire, characterized in that the side groove extends along the side portion from one end formed on the circumferential side from the cross-sectional center of the tire to the other end formed on the rotation center side from the cross-sectional center.

3. In paragraph 2, The above side home, An airless tire characterized in that the depth of the side groove gradually increases as it extends along the side portion from one end of the circumferential side of the side groove toward the center of the cross-section.

4. In paragraph 3, The above side home, An airless tire characterized in that the depth of the side groove gradually decreases as it extends along the side portion from a point where a straight line extending parallel to the rotational axis of the tire from the center of the cross-section intersects the side groove to the other end of the side groove on the rotational center side.

5. In paragraph 3, The above side home, An airless tire characterized in that the depth of the side groove gradually increases as it extends along the side portion from a point where a straight line extending parallel to the rotational axis of the tire from the center of the cross-section intersects the side groove to the other end of the side groove on the rotational center side.

6. In paragraph 3, The above side groove includes a first segment forming one inner wall of the side groove and a second segment forming the other inner wall of the side groove, An airless tire, characterized in that at least a portion of the first segment and the second segment extend with different curvatures.

7. In paragraph 6, As the above side groove extends along the side portion from one end on the circumference side to the other end on the rotation center side, An airless tire characterized in that the distance between the first segment and the second segment gradually increases and then decreases.

8. In paragraph 2, An airless tire, characterized in that the maximum depth of penetration toward the center of the cross-section of the side groove is 5 mm or more.

9. In paragraph 2, An airless tire, characterized in that the extension length of the side groove is at least 1 / 4 of the length from the peripheral end of the grounding portion to the end of the fastening portion of the side portion.

10. An airless tire, characterized in that, in the second paragraph, a plurality of side grooves formed on each side of the grounding portion are formed symmetrically with respect to the grounding portion.

11. An airless tire, characterized in that, in the second paragraph, a plurality of side grooves formed on the side portions on both sides of the grounding portion are alternately formed based on the grounding portion.

12. An airless tire characterized in that it further includes an outer groove formed along the circumference of the tire between the ground portion and the side portion in the second paragraph.

Images