Core material for elastic crawler, and elastic crawler

Abstract

To provide a core material for an elastic crawler capable of being returned to a normal position even when a skid or twist occurs, and to provide an elastic crawler.SOLUTION: A core material 3 for an elastic crawler is embedded in an endless belt-like crawler body made of an elastic body. The core material 3 for the elastic crawler includes a core material body 8 extending in a second direction b, a first projection 9A protruding to one side in a first direction a from the core material body 8, and a second projection 9B protruding to the other side in the first direction a from the core material body 8 on an inside bi in the second direction b beyond the first projection 9A. The first projection 9A is shaped to be convex toward an outside bo in the second direction b due to a first engagement surface 10A, a first flat surface, and a first curved surface. The second projection 9B is shaped to be convex toward the inside bi in the second direction b due to a second engagement surface 10B, a second flat surface, and a second curved surface.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an elastic crawler core material that is embedded in an endless belt-shaped crawler body made of an elastic body, and to an elastic crawler including the elastic crawler core material. [Background technology]

[0002] Conventionally, there is known an elastic crawler including an endless belt-shaped crawler body made of an elastic body and an elastic crawler core material embedded in the crawler body at intervals in the crawler circumferential direction. For example, the following Patent Document 1 proposes an elastic crawler in which the core material includes a core material body extending in the crawler width direction and a wheel-running prevention protrusion protruding from the core material body to one side and the other side in the crawler circumferential direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-011128 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the core material of Patent Document 1, when lateral displacement or twisting occurs and the derailment prevention protrusion becomes displaced from the normal meshing position, if the derailment prevention protrusion has a V-shaped surface, the V-shaped surfaces come into surface contact with each other, causing large resistance and making it difficult to return to the normal meshing position. Also, in the core material of Patent Document 1, if the derailment prevention protrusion has an arcuate surface, the vicinity of the apex of the arcuate surface faces in the crawler thickness direction, so that the restoring force generated in the crawler width direction to return to the normal meshing position may not act easily.

[0005] The present invention was devised in consideration of the above-mentioned circumstances, and its main object is to provide a core material for an elastic crawler and an elastic crawler that can easily return to their normal position even if they are displaced or twisted laterally. [Means for solving the problem]

[0006] The present invention relates to a core material for an elastic crawler that is embedded in an endless band-shaped crawler body made of an elastic body, and when a first direction corresponding to the crawler circumferential direction, a second direction corresponding to the crawler width direction, and a third direction corresponding to the crawler thickness direction are defined, the core material includes a core material body extending in the second direction, a first protrusion protruding from the core material body to one side in the first direction, and a second protrusion protruding from the core material body to the other side in the first direction, on the inside of the first protrusion in the second direction, the first protrusion having a shape that is convex toward the outside in the second direction due to a first engagement surface, a first flat surface, and a first curved surface, the first engagement surface extends along the third direction on the inside of the second direction, and the first flat surface is a curved surface extending in the third direction. the second projection has a shape that is convex toward the inside in the second direction due to the second engagement surface, the second plane and the second curved surface, the second engagement surface extends parallel to the first engagement surface outside in the second direction, the second plane extends in a direction that is inclined linearly relative to the second engagement surface inside in the second direction than the second engagement surface, and the second curved surface connects to the second plane and extends in a direction that is inclined curvedly opposite to the second plane. Effect of the Invention

[0007] By virtue of having the above-described configuration, the elastic crawler core material of the present invention can easily return to its normal position even if it is displaced laterally or twisted. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an embodiment of an elastic crawler of the present invention. FIG. [Diagram 2] FIG. 2 is a perspective view showing a core material for an elastic crawler. [Diagram 3] FIG. 4 is a plan view conceptually showing an arrangement state of elastic crawler core materials. [Figure 4]FIG. 4 is an end view of line AA in FIG. 3. [Diagram 5] 13 is an enlarged view of a wheel-disengagement prevention protrusion in a state displaced from its normal meshing position. [Figure 6] FIG. 6 is an end view of the line BB in FIG. 5 . [Figure 7] 13 is an explanatory diagram showing an example of a wheel-off prevention protrusion that returns to a normal meshing position. FIG. [Figure 8] 13 is an explanatory diagram showing another example of a wheel derailment prevention protrusion that returns to its normal meshing position. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view showing an elastic crawler 1 of this embodiment. As shown in Fig. 1, the elastic crawler 1 of this embodiment includes an endless belt-like crawler body 2 made of an elastic body such as rubber, and a plurality of elastic crawler core materials 3 embedded in the crawler body 2. The elastic crawler 1 desirably includes a tension member 4 embedded in the crawler body 2.

[0010] In this specification, the direction indicated by the symbol X in Fig. 1 is defined as the crawler circumferential direction X, which corresponds to the rotational direction of the elastic crawler 1. Moreover, the direction indicated by the symbol Y in Fig. 1 is defined as the crawler width direction Y, which corresponds to the axial direction of a drive wheel (not shown) when the elastic crawler 1 is mounted on a vehicle.

[0011] 1 is defined as the crawler thickness direction Z, which corresponds to a direction perpendicular to the crawler circumferential direction X and the crawler width direction Y. In the crawler thickness direction Z, the inside of the endless belt-shaped elastic crawler 1 is defined as the crawler inner circumference side Zi, and the outside of the endless belt-shaped elastic crawler 1 is defined as the crawler outer circumference side Zo.

[0012] The crawler body 2 has, for example, a substantially constant width and extends continuously in the crawler circumferential direction X. It is preferable that a plurality of lugs 5 are arranged at intervals in the crawler circumferential direction X on a surface 2o of the crawler outer circumferential side Zo of the crawler body 2. Since such lugs 5 extend in the crawler width direction Y, it is possible to improve traction when traveling on rough terrain.

[0013] For example, two rows of protrusions 6 each consisting of a plurality of protrusions 6a are formed on the surface 2i of the crawler inner circumference side Zi of the crawler body 2. Such protrusion rows 6, 6 can guide the driving wheels, idler wheels, rollers, etc. of the vehicle body between them. Note that the protrusions 6a are desirably reinforced by guide protrusions 7 provided on the elastic crawler core material 3.

[0014] The elastic crawler core material 3 of this embodiment functions as a reinforcing material in the crawler width direction Y, and is arranged at intervals in the crawler circumferential direction X. The elastic crawler core material 3 is desirably made of a material harder than the elastic body. As this hard material, for example, a metal material such as steel or cast iron is preferably used. Such an elastic crawler core material 3 has excellent rigidity and can improve stability when traveling on rough ground.

[0015] Fig. 2 is a perspective view showing the elastic crawler core material 3 of this embodiment. As shown in Fig. 2, the elastic crawler core material 3 of this embodiment includes a core material body 8 extending in the second direction b, and a pair of wheel derailment prevention projections 9 projecting from the core material body 8 in the first direction a.

[0016] Here, in this specification, the direction of the elastic crawler core material 3 before being embedded in the crawler body 2 is defined to correspond to the direction of the elastic crawler 1. The direction indicated by the symbol a in Fig. 2 is defined as the first direction a, which corresponds to the crawler circumferential direction X in Fig. 1. Moreover, the direction indicated by the symbol b in Fig. 2 is defined as the second direction b, which corresponds to the crawler width direction Y in Fig. 1. In the second direction b, an inner side bi of the second direction b and an outer side bo of the second direction b are defined.

[0017] 2 is defined as a third direction c, which corresponds to the crawler thickness direction Z in Fig. 1. In the third direction c, a third inner circumference side ci corresponding to the crawler inner circumference side Zi in Fig. 1 and a third outer circumference side co corresponding to the crawler outer circumference side Zo in Fig. 1 are defined.

[0018] The core body 8 of this embodiment includes an engagement portion 8a disposed in the center in the second direction b, and wing portions 8b disposed on both outer sides of the engagement portion 8a in the second direction b. The surface of the third inner circumference side ci of the engagement portion 8a is formed, for example, as a convex arc surface on the third inner circumference side ci. Such an engagement portion 8a is smooth when meshing with the tooth groove portion of the drive wheel, and can also solve the problem of suppressing vibration and noise.

[0019] The core material 3 for an elastic crawler in this embodiment includes a pair of guide protrusions 7 that protrude in the third direction c from the surface of the third inner periphery side ci of the core material main body 8. The pair of guide protrusions 7 are preferably disposed on both sides of the engagement portion 8a in the second direction b. Such a pair of guide protrusions 7 can guide a drive wheel, an idler wheel, a roller, etc. by sandwiching them between them.

[0020] Fig. 3 is a plan view conceptually showing an arrangement state of the elastic crawler core material 3. As shown in Fig. 2 and Fig. 3, the wheel derailment prevention projection 9 of this embodiment includes a first projection 9A projecting from the core material body 8 to one side in the first direction a, and a second projection 9B projecting from the core material body 8 to the other side in the first direction a on the inner side bi in the second direction b of the first projection 9A.

[0021] Fig. 4 is an end view of line AA in Fig. 3. As shown in Fig. 3 and Fig. 4, the first projection 9A of this embodiment has a substantially triangular shape in which the cross-sectional shape perpendicular to the first direction a is convex toward the outside bo in the second direction b, due to the first engagement surface 10A, the first flat surface 11A, and the first curved surface 12A. Such a first projection 9A can also solve the problem of achieving both engagement performance at the normal meshing position by the first engagement surface 10A and weight reduction by the first flat surface 11A and the first curved surface 12A.

[0022] The first engagement surface 10A of this embodiment extends along the third direction c on the inner side bi of the second direction b. Here, extending along the third direction c means extending at an angle of ±10° or less with respect to the third direction c. It is preferable that the first plane 11A extends in a direction inclined linearly from one side of the third direction c to the first engagement surface 10A on the outer side bo of the second direction b than the first engagement surface 10A. The first curved surface 12A of this embodiment is connected to the first plane 11A and extends in a direction inclined in a curved shape in the opposite direction to the first plane 11A toward the other side of the third direction c. As a result, the first plane 11A and the first curved surface 12A are located on the same side in the second direction b, that is, on the outer side bo of the second direction b in this embodiment.

[0023] The second projection 9B of this embodiment has a substantially triangular shape in which the cross-sectional shape perpendicular to the first direction a is convex toward the inside bi in the second direction b, due to the second engagement surface 10B, the second flat surface 11B, and the second curved surface 12B. Such a second projection 9B can also solve the problem of achieving both engagement performance at the normal meshing position by the second engagement surface 10B and weight reduction by the second flat surface 11B and the second curved surface 12B.

[0024] The second engagement surface 10B of this embodiment extends parallel to the first engagement surface 10A on the outer side bo of the second direction b. Here, extending parallel means that the angle between them is within 10°. The second plane 11B desirably extends in a direction inclined linearly with respect to the second engagement surface 10B from one side of the third direction c, which is the same side as the first plane 11A, on the inner side bi of the second engagement surface 10B in the second direction b. The second curved surface 12B of this embodiment is connected to the second plane 11B and extends in a direction inclined in a curved shape in the opposite direction to the second plane 11B toward the other side of the third direction c, which is the same side as the first curved surface 12A. As a result, the first plane 11A and the first curved surface 12A are located on the same side in the second direction b, which is the inner side bi of the second direction b in this embodiment.

[0025] 3, in this embodiment, the distance L1 in the second direction b between the first engagement surfaces 10A of the pair of first protrusions 9A is greater than the distance L2 in the second direction b between the second engagement surfaces 10B of the pair of second protrusions 9B. In such a wheel derailment prevention protrusion 9, the first engagement surface 10A and the second engagement surface 10B come into contact with each other in the normal meshing position, thereby suppressing lateral displacement in the second direction b of the elastic crawler core material 3 adjacent to the first direction a, and preventing the drive wheels, idler wheels, rollers, etc. from derailing.

[0026] Fig. 5 is an enlarged view of the derailment prevention protrusions 9 in a state where they are displaced from the normal meshing position, and Fig. 6 is an end view of line BB in Fig. 5. As shown in Fig. 5 and Fig. 6, even when the derailment prevention protrusions 9 of this embodiment are displaced from the normal meshing position due to lateral displacement or twisting, the contact resistance between the derailment prevention protrusions 9 is small, and they can be immediately returned to the normal meshing position with a small restoring force.

[0027] For this reason, even if the elastic crawler core material 3 of this embodiment temporarily moves out of its normal meshing position due to lateral shift or twisting, it can immediately return to its normal meshing position, thereby preventing the drive wheels, idler wheels, rollers, etc. from coming off the tracks.

[0028] Fig. 7 is an explanatory diagram showing an example of the wheel derailment prevention protrusion 9 returning to the normal meshing position, and Fig. 8 is an explanatory diagram showing another example of the wheel derailment prevention protrusion 9 returning to the normal meshing position. As shown in Fig. 7 and Fig. 8, the wheel derailment prevention protrusion 9 of this embodiment returns along the path shown in Fig. 7 or Fig. 8 when returning from a state displaced from the normal meshing position shown in Fig. 6 to the normal meshing position shown in Fig. 4.

[0029] In Fig. 7, for example, the first flat surface 11A on one side and the second curved surface 12B on the other side of adjacent elastic crawler core materials 3 are in contact with each other. In Fig. 8, for example, the first curved surface 12A on one side and the second flat surface 11B on the other side are in contact with each other.

[0030] Since the contacting surfaces of the anti-runoff projections 9 are flat, they can be returned to their normal meshing position with a small restoring force no matter where they come into contact. Therefore, the elastic crawler core material 3 of this embodiment can be easily returned to its normal position even if it is displaced or twisted.

[0031] 4, in a more preferred embodiment, the first flat surface 11A extends from one side in the third direction c, in this embodiment from the third inner circumferential side ci, to a first position 9a which is the center of the first protrusion 9A in the third direction c. The first curved surface 12A extends from the other side in the third direction c, in this embodiment from the third outer circumferential side co, to the first position 9a. The first flat surface 11A and the first curved surface 12A may be arranged in opposite directions in the third direction c.

[0032] When such a first protrusion 9A returns to the normal meshing position of FIG. 4 from a state in which it has disengaged from the normal meshing position of FIG. 6, it can be returned with the same restoring force regardless of whether it takes the path shown in FIG. 7 or FIG. 8.

[0033] The first flat surface 11A is inclined at an angle θ1 of preferably 40 to 60° with respect to the first engagement surface 10A. When the angle θ1 of the first flat surface 11A is 40° or more, the contact resistance with the second curved surface 12B can be reliably reduced. When the angle θ1 of the first flat surface 11A is 60° or less, the first projection 9A is prevented from becoming excessively large, which helps to reduce the weight of the elastic crawler core material 3.

[0034] The first curved surface 12A has a cross section perpendicular to the first direction a, i.e., an arc shape that is convex toward the outside bo in the second direction b in Fig. 4. Such a first curved surface 12A helps to reduce the contact resistance regardless of the contact position with the second flat surface 11B.

[0035] The radius of curvature R1 of the first curved surface 12A is preferably 5 to 15 mm. When the radius of curvature R1 of the first curved surface 12A is 5 mm or more, the contact resistance can be reduced, which helps to return the first curved surface 12A to the normal meshing position with a small restoring force. When the radius of curvature R1 of the first curved surface 12A is 15 mm or less, the contact area with the second plane 11B can be reduced, which helps to return the first curved surface 12A to the normal meshing position with a small restoring force.

[0036] As shown in Figures 3 and 5, the first projection 9A of this embodiment has a first end 9c in a first direction a. It is desirable that the width W1 of the first end 9c in the second direction b gradually decreases in a direction away from the core body 8. For example, the width W1 of the first end 9c in the second direction b gradually decreases in an arc shape. When such a first projection 9A is displaced from the normal meshing position as shown in Figure 5, it is possible to reduce the contact area with the second projection 9B, which helps to reduce contact resistance.

[0037] 4, the second plane 11B extends from one side in the third direction c, which is the same side as the first plane 11A, from the third inner peripheral side ci in this embodiment, to a second position 9b that is the center of the second protrusion 9B in the third direction c. The second curved surface 12B extends from the other side in the third direction c, which is the same side as the first curved surface 12A, from the third outer peripheral side co in this embodiment, to the second position 9b. When the first plane 11A and the first curved surface 12A are arranged in the opposite directions in the third direction c, the second plane 11B and the second curved surface 12B are also arranged in the opposite directions.

[0038] When such a second protrusion 9B returns from a state in which it has disengaged from the normal meshing position in Figure 6 to the normal meshing position in Figure 4, it can be returned with the same restoring force regardless of whether it is returned via the path in Figures 7 or 8.

[0039] The second flat surface 11B is inclined at an angle θ2 of preferably 40 to 60° with respect to the second engagement surface 10B. When the angle θ2 of the second flat surface 11B is 40° or more, the contact resistance with the first curved surface 12A can be reliably reduced. When the angle θ2 of the second flat surface 11B is 60° or less, the second projection 9B is prevented from becoming excessively large, which helps to reduce the weight of the elastic crawler core material 3.

[0040] In this embodiment, the angle θ2 of the second plane 11B is equal to the angle θ1 of the first plane 11A. When the wheel derailment prevention projection 9 returns from the state where it is displaced from the normal meshing position in Fig. 6 to the normal meshing position in Fig. 4, it can be returned with the same restoring force regardless of which path is taken in Fig. 7 or Fig. 8.

[0041] The second curved surface 12B has a cross section perpendicular to the first direction a, i.e., an arc shape that is convex toward the inside bi in the second direction b in Fig. 4. Such a second curved surface 12B helps to reduce contact resistance regardless of the contact position with the first plane 11A.

[0042] The radius of curvature R2 of the second curved surface 12B is preferably 5 to 15 mm. When the radius of curvature R2 of the second curved surface 12B is 5 mm or more, the contact resistance can be reduced, which helps to return the second curved surface 12B to the normal meshing position with a small restoring force. When the radius of curvature R2 of the second curved surface 12B is 15 mm or less, the contact area with the first plane 11A can be reduced, which helps to return the second curved surface 12B to the normal meshing position with a small restoring force.

[0043] In this embodiment, the radius of curvature R2 of the second curved surface 12B is equal to the radius of curvature R1 of the first curved surface 12A. When the wheel derailment prevention projection 9 is returned to the normal meshing position of Fig. 4 from the state where it is displaced from the normal meshing position of Fig. 6, it can be returned with the same restoring force regardless of the path of Fig. 7 or Fig. 8.

[0044] As shown in Figures 3 and 5, the second projection 9B of this embodiment has a second end 9d in the first direction a. It is desirable that the width W2 of the second end 9d in the second direction b gradually decreases in the direction away from the core body 8. For example, the width W2 of the second end 9d in the second direction b gradually decreases in an arc shape. When such a second projection 9B is displaced from the normal meshing position as shown in Figure 5, it is possible to reduce the contact area with the first projection 9A, which helps to reduce contact resistance.

[0045] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified in various ways. EXAMPLES

[0046] An elastic crawler in which an elastic crawler core material having the basic structure of Figures 1 to 4 is embedded was prototyped based on the specifications in Table 1, and its anti-runoff performance was tested. In Table 1, when the first protrusion is composed of one first engagement surface and two first flat surfaces, it is shown as "first flat surface + first flat surface," and when it is composed of one first engagement surface and two first curved surfaces, it is shown as "first curved surface + first curved surface."

[0047] In addition, in Table 1, when the first protrusion is composed of one first engagement surface, one first flat surface, and one first curved surface, as in the embodiment, it is indicated as "first flat surface + first curved surface." In Table 1, the explanation of the second protrusion is omitted, but it is the same as the first protrusion. The common specifications and test method are as follows.

[0048] <Common specifications> Test vehicle: Mini backhoe

[0049] <Prevention of wheel slippage> The prototype elastic crawler was attached to the running gear of a test vehicle, and running tests were conducted, including climbing over protrusions and turning, to measure the frequency with which the elastic crawler derailed. The results were expressed as an index, with the comparative example being set at 100, and a higher index value indicates a lower frequency of derailment and better performance in preventing derailment.

[0050] The test results are shown in Table 1. [Table 1]

[0051] As a result of the tests, it was confirmed that the elastic crawler core material of the embodiment has improved anti-skid performance compared to the comparative example, and can easily return to its normal position even when it shifts sideways or twists.

[0052] [Note] The present invention is as follows.

[0053] [Invention 1] An elastic crawler core material to be embedded in an endless belt-shaped crawler body made of an elastic body, When a first direction corresponding to the crawler circumferential direction, a second direction corresponding to the crawler width direction, and a third direction corresponding to the crawler thickness direction are defined, A core body extending in the second direction; A first projection protruding from the core body to one side in the first direction; a second projection protruding from the core body to the other side in the first direction on the inner side of the first projection in the second direction, the first projection has a shape that is convex outward in the second direction due to a first engagement surface, a first flat surface, and a first curved surface; The first engagement surface extends along the third direction on the inner side of the second direction, the first plane extends outwardly of the first engagement surface in the second direction from one side in the third direction in a direction linearly inclined with respect to the first engagement surface, the first curved surface is continuous with the first plane and extends in a direction inclined in a curved shape in a direction opposite to the first plane toward the other side in the third direction, the second projection has a shape that is convex toward the inside in the second direction by a second engagement surface, a second flat surface, and a second curved surface, The second engagement surface extends parallel to the first engagement surface on the outside in the second direction, the second plane extends inwardly of the second engagement surface in the second direction from one side in the third direction in a direction linearly inclined with respect to the second engagement surface, The second curved surface is continuous with the second plane and extends in a direction inclined in a curved shape in a direction opposite to the second plane toward the other side in the third direction. Core material for elastic crawlers.

[0054] [Invention 2] When the third inner circumference side corresponding to the inner circumference side of the crawler is defined, the first plane extends from the third inner circumferential side to a first position that is a center of the first protrusion in the third direction, The core material for an elastic crawler according to claim 1, wherein the second plane extends from the third inner circumference side to a second position that is the center of the second projection in the third direction.

[0055] [Invention 3] In a cross section perpendicular to the first direction, the first curved surface has an arc shape that is convex outward in the second direction, 3. The core material for an elastic crawler according to claim 1 or 2, wherein the second curved surface is an arcuate surface that is convex toward the inside in the second direction.

[0056] [Invention 4] The core material for an elastic crawler according to invention 3, wherein the radius of curvature of the first curved surface and the radius of curvature of the second curved surface are each 5 to 15 mm.

[0057] [Invention 5] The first plane is inclined at an angle of 40 to 60 degrees with respect to the first engagement surface, 5. The core material for an elastic crawler according to any one of claims 1 to 4, wherein the second flat surface is inclined at an angle of 40 to 60° with respect to the second engagement surface.

[0058] [Invention 6] the first projection has a first end in the first direction; A core material for an elastic crawler according to any one of claims 1 to 5, wherein the first end portion has a width in the second direction that gradually decreases in a direction away from the core material body.

[0059] [Invention 7] the second protrusion has a second end in the first direction; A core material for an elastic crawler as described in invention 6, wherein the width of the second end in the second direction gradually decreases in a direction away from the core material body.

[0060] [Invention 8] An elastic crawler comprising the core material for an elastic crawler according to any one of the present inventions 1 to 7 and the crawler body. [Explanation of symbols]

[0061] 2 Crawler body 3. Core material for elastic crawlers 8 Core body 9A 1st protrusion 9B 2nd protrusion 10A 1st engagement surface 10B 2nd engagement surface 11A 1st plane 11B 2nd plane 12A 1st curved surface 12B 2nd curved surface

Claims

1. An elastic crawler core material to be embedded in an endless belt-shaped crawler body made of an elastic body, When a first direction corresponding to the crawler circumferential direction, a second direction corresponding to the crawler width direction, and a third direction corresponding to the crawler thickness direction are defined, A core body extending in the second direction; a first projection protruding from the core body to one side in the first direction; a second projection protruding from the core body to the other side in the first direction on the inner side of the first projection in the second direction, the first projection has a shape that is convex outward in the second direction due to a first engagement surface, a first flat surface, and a first curved surface; The first engagement surface extends along the third direction on the inner side of the second direction, the first plane extends outwardly of the first engagement surface in the second direction from one side in the third direction in a direction linearly inclined with respect to the first engagement surface, the first curved surface is continuous with the first plane and extends in a direction inclined in a curved shape in a direction opposite to the first plane toward the other side in the third direction, the second projection has a shape that is convex toward the inside in the second direction by a second engagement surface, a second flat surface, and a second curved surface, The second engagement surface extends parallel to the first engagement surface on the outside in the second direction, the second plane extends inwardly of the second engagement surface in the second direction from one side in the third direction in a direction linearly inclined with respect to the second engagement surface, The second curved surface is continuous with the second plane and extends in a direction inclined in a curved shape in a direction opposite to the second plane toward the other side in the third direction. Core material for elastic crawlers.

2. When the third inner circumference side corresponding to the inner circumference side of the crawler is defined, the first plane extends from the third inner circumferential side to a first position that is a center of the first protrusion in the third direction, The core material for an elastic crawler according to claim 1 , wherein the second plane extends from the third inner peripheral side to a second position that is a center of the second projection in the third direction.

3. In a cross section perpendicular to the first direction, the first curved surface has an arc shape that is convex outward in the second direction, The core material for an elastic crawler according to claim 1 , wherein the second curved surface is an arcuate surface that is convex toward the inside in the second direction.

4. 4. The core material for an elastic crawler according to claim 3, wherein the radius of curvature of the first curved surface and the radius of curvature of the second curved surface are each 5 to 15 mm.

5. The first plane is inclined at an angle of 40 to 60 degrees with respect to the first engagement surface, 2. The core material for an elastic crawler according to claim 1, wherein the second plane is inclined at an angle of 40 to 60 degrees with respect to the second engagement surface.

6. The first projection has a first end in the first direction, The core material for an elastic crawler according to claim 1 , wherein the width of the first end in the second direction gradually decreases in a direction away from the core material body.

7. the second projection has a second end in the first direction; The core material for an elastic crawler according to claim 6 , wherein the width of the second end portion in the second direction gradually decreases in a direction away from the core material body.

8. An elastic crawler comprising: the core material for an elastic crawler according to claim 1; and the crawler body.

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