Elastic crawler and method for detecting wire breakage in elastic crawler

Abstract

To provide an elastic crawler capable of readily detecting a disconnection of a steel cord, and a disconnection detection method of the elastic crawler.SOLUTION: An elastic crawler 11 includes a crawler body 11a made of a rubber elastic material and formed in an endless manner, a tension member 40 incorporated in the crawler body 11a and wound in a circumferential direction of the crawler body 11a, and plural core metals 30 incorporated in the crawler body 11a and disposed equidistantly in a circumferential direction of the crawler body 11a. The tension member 40 is formed with a steel cord 41 wound spirally in the circumferential direction of the crawler body 11a. The steel cord 41 is electrically connected to the plural core metals 30 at one end 41a and the other end 41b in a length direction of the steel cord 41. The one end 41a and the other end 41b are connected to a first core metal 30a and forth core metal 30d respectively that are mutually different core metals 30.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a technique for detecting breaks in steel cords that constitute an elastic crawler. [Background technology]

[0002] Conventionally, crawler-type traveling devices use endless elastic crawlers. The elastic crawler includes an endless crawler body made of a rubber-like elastic material, a tension member built into the crawler body and wound around the circumferential direction, and a plurality of core wires built into the crawler body and spaced apart around the circumferential direction. The tension member is, for example, a steel cord wound spirally around the circumferential direction of the crawler body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-114144 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle using a conventional crawler traveling device, if the steel cord that makes up the elastic crawler breaks, the vehicle may become unable to travel. However, because it has been difficult to detect a break in the steel cord, a break in the steel cord was often only noticed after it had affected the vehicle's travel.

[0005] An object of the present invention is to provide an elastic crawler that can easily detect breaks in steel cords, and a break detection method therefor. [Means for solving the problem]

[0006] (1) The elastic crawler of the present invention comprises a crawler body made of a rubber-like elastic material and formed in an endless shape, a tension body built into the crawler body and wound around the circumferential direction of the crawler body, and a plurality of core wires built into the crawler body and arranged at intervals around the circumferential direction of the crawler body, wherein the tension body is formed of a steel cord wound spirally around the circumferential direction of the crawler body, and the steel cord is electrically connected to the plurality of core wires only at one end and the other end in the longitudinal direction of the steel cord, and the one end and the other end are connected to different core wires.

[0007] With the elastic crawler of the above configuration, breaks in the steel cord can be easily detected by measuring the resistance value between the first core bar to which one end of the steel cord is connected and the second core bar to which the other end of the steel cord is connected.

[0008] (2) In the elastic crawler according to the present invention, it is preferable that the tension body includes a steel cord group having a plurality of the steel cords as a unit, and that the one ends of all the steel cords included in the steel cord group are connected to the same core bar, and that the other ends of all the steel cords included in the steel cord group are connected to the same core bar. According to the elastic crawler having the above configuration, when the tension body includes a steel cord group, each group consisting of a plurality of steel cords, breakage of the steel cords can be detected.

[0009] (3) In the elastic crawler according to the present invention, it is preferable that the first tension body and the second tension body are arranged side by side in the width direction of the crawler body, one end of the first steel cord constituting the first tension body and one end of the second steel cord constituting the second tension body are connected to the same core bar, and the other end of the first steel cord and the other end of the second steel cord are connected to the same core bar. According to the elastic crawler having the above configuration, when the elastic crawler includes two steel cords, it is possible to easily detect whether a break has occurred in one of the steel cords.

[0010] (4) In the elastic crawler according to the present invention, it is preferable that the first tension body and the second tension body are arranged side by side in the width direction of the crawler body, and that one end of the first steel cord constituting the first tension body and one end of the second steel cord constituting the second tension body are connected to the same core bar, or that the other end of the first steel cord and the other end of the second steel cord are connected to the same core bar. According to the elastic crawler having the above configuration, when the elastic crawler includes two steel cords, when detecting a break in a steel cord, it is possible to determine which steel cord has the break.

[0011] (5) In the elastic crawler according to the present invention, it is preferable that the first tension body and the second tension body are arranged side by side in the width direction of the crawler body, one end of the first steel cord constituting the first tension body and one end of the second steel cord constituting the second tension body are connected to different core wires, and the other end of the first steel cord and the other end of the second steel cord are connected to different core wires. According to the elastic crawler having the above configuration, when the elastic crawler includes two steel cords, when detecting a break in a steel cord, it is possible to determine which steel cord has the break.

[0012] (6) In the elastic crawler according to the present invention, it is preferable that a part of the core metal to which the one end and the other end are connected is exposed from the crawler body. With the elastic crawler having the above configuration, the resistance value of the steel cord can be easily measured by using the portions of the first and second core wires exposed from the crawler body as the portions to be contacted with a measuring tool.

[0013] (7) In the elastic crawler according to the present invention, it is preferable that the core metal to which the one end and the other end are connected is adhered to the crawler body by a conductive adhesive. The elastic crawler having the above configuration can reliably ensure conductivity between the core metal and the steel cord, which makes it possible to reliably measure the resistance value of the steel cord and accurately detect breaks in the steel cord.

[0014] (8) In the elastic crawler according to the present invention, the radial dimension of the one end and the other end of the steel cord is preferably larger than the radial dimension of the steel cord other than the one end and the other end. According to the elastic crawler having the above configuration, the connection area of ​​the steel cord with respect to the core can be increased, thereby reliably ensuring electrical conductivity between the steel cord and the core.

[0015] (9) In the elastic crawler according to the present invention, it is preferable that the radial dimension of the one end and the other end of the steel cord is smaller than the radial dimension of the steel cord other than the one end and the other end. According to the elastic crawler having the above configuration, rust occurring on the core metal can be made less likely to spread to the steel cord.

[0016] (10) In the elastic crawler according to the present invention, it is preferable that the one end and the other end of the steel cord are in direct contact with the core metal. According to the elastic crawler having the above configuration, electrical conductivity between the steel cord and the core can be reliably ensured.

[0017] (11) In the elastic crawler according to the present invention, it is preferable that a coating portion made of a conductive material is provided on the one end and the other end of the steel cord, and that the one end and the other end are electrically connected to the core wire via the coating portion. According to the elastic crawler having the above configuration, rust occurring on the core metal can be made less likely to spread to the steel cord.

[0018] (12) In the elastic crawler according to the present invention, it is preferable that the one end and the other end of the steel cord are bent toward the inner periphery of the crawler body. According to the elastic crawler having the above configuration, electrical conductivity between the steel cord and the core can be reliably ensured.

[0019] (13) In the elastic crawler according to the present invention, it is preferable that the steel cord includes a joint made of a conductive material, which is arranged midway in the longitudinal direction. According to the elastic crawler having the above configuration, even when a plurality of steel cords are spliced ​​together, it is possible to detect breaks in the steel cords.

[0020] (14) A wire break detection method for an elastic crawler according to the present invention comprises a crawler body made of a rubber-like elastic material and formed in an endless shape, a tension body built into the crawler body and wound around the circumferential direction of the crawler body, and a plurality of core wires built into the crawler body and arranged at intervals around the circumferential direction of the crawler body, the tension body being a steel cord wound spirally around the circumferential direction of the crawler body, the steel cord being electrically connected to the plurality of core wires only at one end and the other end in the length direction of the steel cord, the one end and the other end being connected to different core wires, the resistance value between one of the core wires to which the one end is connected and the other of the core wires to which the other end is connected is measured, and a wire break in the steel cord is detected based on the resistance value.

[0021] According to the elastic crawler break detection method configured as described above, breaks in the steel cord can be easily detected by measuring the resistance value between the core bar to which one end of the steel cord is connected and the core bar to which the other end of the steel cord is connected. [Effects of the Invention]

[0022] According to the present invention, breakage of a steel cord in an elastic crawler including a steel cord can be easily detected. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a side view showing a part of a traveling device equipped with elastic crawlers according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a perspective view showing a steel cord constituting a tension member. [Figure 4] FIG. 2 is a plan view illustrating a first configuration example of a tension body. [Figure 5] FIG. 10 is a plan view illustrating a second configuration example of the tension body. [Figure 6] FIG. 10 is a plan view illustrating a third configuration example of the tension body. [Figure 7A] 1 is a cross-sectional view showing a first configuration example of a connection portion between one end of a steel cord and a core metal. FIG. [Figure 7B] FIG. 10 is a cross-sectional view showing a second configuration example of a connection portion between one end of a steel cord and a core metal. [Figure 7C] FIG. 10 is a cross-sectional view showing a third configuration example of a connection portion between one end of a steel cord and a core metal. [Figure 8] FIG. 2 is a cross-sectional view showing a first example of connection between a pair of steel cords and a core bar. [Figure 9] FIG. 10 is a cross-sectional view showing a second example of connection between a pair of steel cords and a core bar. [Figure 10] FIG. 10 is a cross-sectional view showing a third example of connection between a pair of steel cords and a core bar. [Figure 11] 1 is an explanatory diagram of a method for detecting a break in a steel cord according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, the present invention will be described in detail based on preferred embodiments, with appropriate reference to the drawings.

[0025] [Running gear] FIG. 1 shows a portion of a crawler-type traveling device 10. Examples of the traveling device 10 include agricultural machinery such as combine harvesters and tractors, and construction machinery such as backhoes. The traveling device 10 includes elastic crawlers 11, sprockets 12, idlers 13, and rollers 14. In the following description, the front-rear and left-right directions of the traveling device 10 are defined as shown in FIG. 1 based on the traveling direction of the traveling device 10, and the direction perpendicular to the front-rear and left-right directions of the traveling device 10 is defined as the up-down direction. In the following description, the front-rear, left-right, and up-down directions defined for the traveling device 10 are also used in the description of the elastic crawler 11. The left-right direction of the traveling device 10 corresponds to the width direction of the elastic crawler 11. The circumferential direction of the elastic crawler 11 is the direction around an axis extending in the left-right direction. In the following description, the direction perpendicular to the width direction of the elastic crawler 11 may be referred to as the radial direction of the elastic crawler 11.

[0026] The elastic crawler 11 is in the form of an endless belt. The elastic crawler 11 has a hole 15 in the center in the width direction. The elastic crawler 11 has a large number of holes 15 arranged at intervals in the circumferential direction. The sprocket 12 and the idler 13 are disk-shaped and rotatably supported on the main body of the traveling device 10. The sprocket 12 has a large number of teeth 16 on its outer periphery.

[0027] In the traveling device 10, the elastic crawler 11 is wound around a sprocket 12 and an idler 13. As a result, a predetermined tension is applied to the elastic crawler 11.

[0028] In the traveling device 10, the sprocket 12 is rotated by a driving means (not shown). As a result, the teeth 16 of the sprocket 12 sequentially fit into the holes 15 of the elastic crawler 11. The teeth 16 that fit into the holes 15 move in the direction of rotation of the sprocket 12, causing the elastic crawler 11 to move in the circumferential direction. This allows the traveling device 10 to travel. As the elastic crawler 11 moves in the circumferential direction, the idler 13 rotates.

[0029] In the traveling device 10, a plurality of rollers 14 are arranged on the side that comes into contact with the road surface. The rollers 14 are located between the sprocket 12 and the idler 13. The rollers 14 are rotatably supported on the main body of the traveling device 10. In the traveling device 10, the rollers 14 roll on the inner circumferential surfaces of the elastic crawlers 11 that move in the circumferential direction.

[0030] [Elastic crawler] Fig. 2 shows a cross section of the elastic crawler 11 taken along line II-II in Fig. 1. Fig. 2 shows a cross section of the elastic crawler 11 taken along a plane perpendicular to the circumferential direction of the elastic crawler 11.

[0031] In FIG. 2, the left-right direction is the width direction of the elastic crawler 11. In FIG. 2, the up-down direction is the thickness direction of the elastic crawler 11. As shown in FIG. 1, the elastic crawler 11 forms a loop. The lower side in FIG. 2 is the inside of the loop, and the upper side in FIG. 2 is the outside of the loop. In FIG. 2, the direction perpendicular to the paper surface is the circumferential direction of the elastic crawler 11. The circumferential direction of the elastic crawler 11 is also the length direction of the elastic crawler 11. The circumferential direction of the elastic crawler 11 is perpendicular to the width direction of the elastic crawler 11.

[0032] The elastic crawler 11 includes, as shape elements, lugs 17 and guides 18 in addition to the holes 15 described above.

[0033] The lugs 17 protrude outward from the crawler body 11a of the elastic crawler 11. The lugs 17 extend generally in the width direction of the elastic crawler 11. As shown in FIG. 1 , the elastic crawler 11 has a large number of lugs 17 arranged at intervals in the circumferential direction. The lugs 17 contribute to the traction of the traveling device 10.

[0034] The guides 18 protrude inward from the crawler body 11a of the elastic crawler 11. As shown in FIG. 1, a large number of guides 18 are arranged at intervals in the circumferential direction of the elastic crawler 11. As shown in FIG. 2, two guides 18 are arranged at an interval in the width direction in the central portion of the elastic crawler 11. The two guides 18 sandwich the sprocket 12 and the like when the elastic crawler 11 is running. This suppresses displacement of the elastic crawler 11 in the width direction. The guides 18 contribute to the running stability of the traveling device 10.

[0035] The elastic crawler 11 includes, as constituent elements, an elastic member 20, a core metal 30, a tension member 40, and a canvas 42.

[0036] The elastic member 20 is made of cross-linked rubber and covers the core metal 30, the tension member 40, and the canvas 42. In the elastic crawler 11, the core metal 30, the tension member 40, and the canvas 42 are embedded in the elastic member 20.

[0037] The core metal 30 is plate-shaped. The core metal 30 includes a base 31, a pair of wing portions 32, and a pair of protrusions 33. The pair of wing portions 32 are plate-shaped. Each of the wing portions 32 extends outward in the width direction from the base 31. In the elastic crawler 11, the aforementioned lugs 17 are formed on the outer side of the core metal 30. The pair of protrusions 33 are arranged in the central portion of the core metal 30 in the width direction.

[0038] As shown in Figure 2, each protrusion 33 protrudes inward from the base 31 of the core metal 30. In the elastic crawler 11, the protrusion 33 of the core metal 30 forms part of the aforementioned guide 18. A part of the base 31 of the core metal 30 and a part of the protrusion 33 are not covered by the crawler body 11a (elastic member 20) and are exposed to the outside.

[0039] In the elastic crawler 11, the core 30 is made of metal and is conductive. Examples of materials for the core 30 include conductive ordinary steel and alloy steel. As shown in FIG. 2, the core 30 is embedded in the crawler body 11a. When the core 30 is embedded in the crawler body 11a, it is bonded to the crawler body 11a with an adhesive to form an integrated unit. In the elastic crawler 11, it is preferable to use an adhesive having conductivity as the adhesive for bonding the crawler body 11a and the core 30. In this case, when the core 30 and the steel cords 41 are electrically connected, the adhesive applied to the core 30 does not impair the conductivity between the core 30 and the steel cords 41.

[0040] The elastic crawler 11 includes a plurality of core metals 30. The core metals 30 are arranged at intervals in the circumferential direction.

[0041] The tension member 40 extends in the circumferential direction. The tension member 40 is in the shape of an endless band. The outer end of the tension member 40 is positioned more inward than the outer end of the core bar 30 in the width direction.

[0042] As shown in FIG. 3, the tension member 40 is composed of steel cords 41. The steel cords 41 extend substantially in the circumferential direction and are wound spirally. Here, "substantially in the circumferential direction" means that the angle that the steel cords 41 form with respect to the circumferential direction is 5° or less. In the elastic crawler 11, from the viewpoint of ensuring the rigidity of the tension member 40, the angle that the steel cords 41 form with respect to the circumferential direction is preferably 3° or less, and more preferably 2° or less. The steel cords 41 have one end 41a and the other end 41b. The steel cords 41 are conductors that are continuous from the one end 41a to the other end 41b.

[0043] In the elastic crawler 11, steel cords used in general elastic crawlers are used as the steel cords 41. Although not shown, the steel cords 41 are formed by twisting together a plurality of strands, each of which is formed by twisting together a plurality of filaments.

[0044] The canvas 42 is a woven fabric. Although not shown, the canvas 42 includes canvas cords made of organic fibers, such as nylon fibers, polyester fibers, rayon fibers, and aramid fibers.

[0045] The canvas 42 is interposed between the core metal 30 and the tension body 40 and extends in the circumferential direction. The canvas 42 is in the form of an endless belt. Although not shown, the elastic crawler 11 may further be provided with an endless belt-shaped canvas extending in the circumferential direction on the outside of the expansion body 40. Note that the elastic crawler 11 does not have the canvas 42 interposed between the core metal 30 and the tension body 40 in the area where the core metal 30 and the tension body 40 are electrically connected (see Figures 7A, 7B, and 7C).

[0046] In the elastic crawler 11, the tension members 40 are located radially outside the core metal 30. As shown in Fig. 2, in the elastic crawler 11, a pair of tension members 40 are arranged side by side in the width direction. Each tension member 40 extends circumferentially radially outside the respective wing portions 32 provided on the left and right sides of the core metal 30.

[0047] The elastic crawler 11 includes a pair of canvases 42. Each canvas 42 extends in the circumferential direction along the tension member 40 on the radially outer side of each of the wing portions 32 provided on the left and right sides of the core metal 30.

[0048] [About the composition of a unit of tension body] 4 to 6 show a portion of one unit of tension body 40 (one of a pair of tension bodies 40, 40) together with the core wire 30, as viewed from the direction of arrow A in FIG. 1. The elastic member 20 and canvas 42 are omitted from FIGS. 4 to 6. In FIGS. 4 to 6, the left-right direction is the width direction of the elastic crawler 11, and the up-down direction is the circumferential direction of the elastic crawler 11. The direction perpendicular to the paper surface is the thickness direction of the elastic crawler 11. The front side of the paper surface is the outside of the loop formed by the elastic crawler 11. Although only one of the pair of tension bodies 40 on the left and right sides of the elastic crawler 11 is shown in FIGS. 4 to 6, the other tension body 40 has the same configuration. Four core wires 30, which are a portion of the multiple core wires 30 that make up the elastic crawler 11, are shown in FIGS. 4 to 6. These four cores 30 are distinguished by being called, in order from the front, a first core 30a, a second core 30b, a third core 30c, and a fourth core 30d.

[0049] A single unit of tension body 40 shown in Fig. 4 is composed of a steel cord 41 that is seamless from one end 41a to the other end 41b. In the tension body 40 shown in Fig. 4, one end 41a of the steel cord 41 is disposed directly above the wing portion 32 of the first core metal 30a, and the other end 41b of the steel cord 41 is disposed directly above the wing portion 32 of the fourth core metal 30d. In the elastic crawler 11, one end 41a of the steel cord 41 is electrically connected to the first core metal 30a, and the other end 41b is electrically connected to the fourth core metal 30d.

[0050] The one end 41a and the other end 41b are electrically connected to the core 30 by, for example, welding, soldering, or the like. The one end 41a and the other end 41b and the core 30 may also be electrically connected by simply contacting them. The canvas 42 is not interposed between the one end 41a and the other end 41b and the core 30 at the connection portions.

[0051] Figure 4 illustrates an example in which one end 41a is connected to the first core bar 30a and the other end 41b is connected to the fourth core bar 30d, but it is sufficient that one end 41a and the other end 41b are connected to different core bars 30, and for example, one end 41a may be connected to the second core bar 30b and the other end 41b may be connected to the third core bar 30c.

[0052] 4, in the elastic crawler 11, portions other than one end 41a and the other end 41b of the steel cord 41 are not electrically connected to the core metal 30. In other words, in the elastic crawler 11, only one end 41a and the other end 41b of the steel cord 41 are connected to different core metals 30. In the elastic crawler 11 configured in this manner, the first core metal 30a and the fourth core metal 30d are used as measurement terminals, making it possible to measure the resistance value between one end 41a and the other end 41b of the steel cord 41.

[0053] The elastic crawler 11 may use a steel cord 41 as shown in FIG. 5. The steel cord 41 shown in FIG. 5 has opposing intermediate ends 41c, 41c along its length, and the intermediate ends 41c are connected by a joint 41d. The joint 41d is, for example, a crimped sleeve used in electrical wiring. The steel cord 41 shown in FIG. 5 is configured as a single continuous steel cord 41, with multiple steel cords 41 arranged adjacent to each other along its length and connected by joints 41d. In other words, the single tension element 40 shown in FIG. 5 differs from the single tension element 40 shown in FIG. 4 in that it is configured by a steel cord 41 having a joint between one end 41a and the other end 41b. An elastic crawler 11 configured in this way can effectively utilize multiple short steel cords 41.

[0054] In the elastic crawler 11 shown in Fig. 5, one end 41a of the steel cord 41 is electrically connected to the first core metal 30a, and the other end 41b is electrically connected to the fourth core metal 30d, similar to the elastic crawler 11 shown in Fig. 4. That is, in the elastic crawler 11 shown in Fig. 5, the one end 41a and the other end 41b are each connected to different core metals 30.

[0055] The elastic crawler 11 may use steel cords 41 as shown in FIG. 6. The steel cords 41 shown in FIG. 6 are configured such that one unit of tension body 40 is made up of two steel cords 41, 41 adjacent in the width direction. In this description, the two steel cords 41, 41 adjacent in the width direction are distinguished by being referred to as a first steel cord 41α and a second steel cord 41β. The elastic crawler 11 shown in FIG. 6 differs from the one unit of tension body 40 shown in FIGS. 4 and 5 in that one unit of tension body 40 is made up of two steel cords 41α, 41β adjacent in the width direction. Note that when one unit of tension body 40 is made up of multiple steel cords 41 adjacent in the width direction, the number of steel cords 41 may be three or more.

[0056] In one unit of tension body 40 shown in Fig. 6, one end 41a1 of the first steel cord 41α and one end 41a2 of the second steel cord 41β are electrically connected to the first core metal 30a, and the other end 41b1 of the first steel cord 41α and the other end 41b2 of the second steel cord 41β are electrically connected to the fourth core metal 30d. That is, in the elastic crawler 11 shown in Fig. 6, the one ends 41a1, 41a2 and the other ends 41b1, 41b2 are connected to different core metals 30. In the elastic crawler 11 shown in Fig. 6, it is possible to measure the resistance value when the first steel cord 41α and the second steel cord 41β are connected in parallel.

[0057] [Regarding the connection points between one end and the other end and the core] As shown in FIG. 7A , a steel cord 41 may be provided with a coating 45 made of a conductive material at one end 41 a, and the steel cord 41 and the core 30 may be electrically connected via the coating 45. In this case, it is preferable that the radial dimension D1 of the coating 45 is larger than the radial dimension D0 of the steel cord 41. The coating 45 is, for example, a conductive material (a crimp sleeve) having an outer diameter larger than that of the steel cord 41. In this configuration, the connection area of ​​the steel cord 41 (coating 45) with the core 30 can be increased compared to when the steel cord 41 is directly connected to the core 30, thereby reliably ensuring conductivity between the steel cord 41 and the core 30. Note that FIG. 7A illustrates an example in which the coating 45 is provided at one end 41 a of the steel cord 41. However, a similar coating 45 may also be provided at the other end 41 b of the steel cord 41, and the other end 41 b and the core 30 may be electrically connected via the coating 45.

[0058] As shown in FIG. 7B , a connecting member 46 made of a conductive material may be provided at one end 41 a of the steel cord 41, and the steel cord 41 and the core 30 may be electrically connected via the connecting member 46. In this case, it is preferable that the radial dimension D2 of the connecting member 46 is smaller than the radial dimension D0 of the steel cord 41. The connecting member 46 is, for example, a conductive material (electric wire) having a smaller wire diameter than the steel cord 41. In this configuration, rust generated on the core 30 is less likely to spread to the steel cord 41 compared to when the steel cord 41 is directly connected to the core 30, thereby ensuring conductivity between the steel cord 41 and the core 30 for a longer period of time. Note that FIG. 7B illustrates an example in which the connecting member 46 is provided at one end 41 a of the steel cord 41. However, a connecting member 46 may also be provided at the other end 41 b of the steel cord 41, and the other end 41 b and the core 30 may be electrically connected via the connecting member 46.

[0059] As shown in Fig. 7C, one end 41a of the steel cord 41 may be directly connected to the core 30. In this case, it is preferable to provide a bent portion 47 in the steel cord 41. With this configuration, the one end 41a can be reliably aligned with the core 30, thereby reliably ensuring conductivity between the steel cord 41 and the core 30. Note that Fig. 7C illustrates an example in which the bent portion 47 is provided near the one end 41a of the steel cord 41, but a bent portion 47 may also be provided near the other end 41b of the steel cord 41 to electrically connect the other end 41b to the core 30.

[0060] [Connection positions of one end and the other end of a pair of tension members] 8 to 10 show an elastic crawler 11 equipped with a pair of left and right tension members 40 in the width direction. In the elastic crawler 11 shown in Figs. 8 to 10, of the pair of left and right tension members 40, the tension member 40 on one side (the right side) is referred to as the first tension member 40X, and the tension member 40 on the other side (the left side) is referred to as the second tension member 40Y. The first tension member 40X is made up of a first steel cord 41X, and the second tension member 40Y is made up of a second steel cord 41Y.

[0061] FIG. 8 shows a first elastic crawler 11X, which is the elastic crawler 11 in which the connection of one end 41a and the other end 41b to the core metal 30 is a first connection example.

[0062] In the first elastic crawler 11X, one end 41a of the first steel cord 41X is connected to the first core metal 30a, and the other end 41b is connected to the fourth core metal 30d. In the first elastic crawler 11X, one end 41a of the second steel cord 41Y is connected to the first core metal 30a, and the other end 41b is connected to the fourth core metal 30d. In other words, in the first elastic crawler 11X, one end 41a of each of the first steel cord 41X and the second steel cord 41Y is electrically connected to the same core metal 30 (here, the first core metal 30a), and the other end 41b of each of the first steel cord 41X and the second steel cord 41Y is electrically connected to the same core metal 30 (here, the fourth core metal 30d). In the first elastic crawler 11X, the core bar 30 to which one end 41a of each of the first steel cord 41X and the second steel cord 41Y is connected may be other than the first core bar 30a, and the core bar 30 to which the other end 41b of each of the first steel cord 41X and the second steel cord 41Y is connected may be other than the fourth core bar 30d.

[0063] In the first elastic crawler 11X configured as described above, the first core metal 30a and the fourth core metal 30d are used as measurement terminals to measure the resistance between the core metals 30a and 30d, thereby making it possible to measure the resistance of the two steel cords 41X, 41Y when they are electrically connected in parallel. Therefore, the first elastic crawler 11X can easily detect a break in at least one of the two steel cords 41X, 41Y. Note that, in the first elastic crawler 11X, when the first core metal 30a and the fourth core metal 30d are used as measurement terminals, it is not possible to identify which of the two steel cords 41X, 41Y has a break. In this configuration, the core metals 30 that serve as measurement terminals are only two, the first core metal 30a and the fourth core metal 30d, so there is no confusion about which core metal 30 to use for resistance measurement, making it easy for the user to measure the resistance.

[0064] FIG. 9 shows a second elastic crawler 11Y, which is an elastic crawler 11 in which the connection of one end 41a and the other end 41b to the core metal 30 is a second connection example.

[0065] In the second elastic crawler 11Y, one end 41a of the first steel cord 41X is connected to the first core metal 30a, and the other end 41b of the first steel cord 41X is connected to the fourth core metal 30d. Furthermore, in the second elastic crawler 11Y, one end 41a of the second steel cord 41Y is connected to the second core metal 30b, and the other end 41b of the second steel cord 41Y is connected to the fourth core metal 30d. That is, in the second elastic crawler 11Y, the core metal 30 to which the other end 41b of the first steel cord 41X is connected and the core metal 30 to which the other end 41b of the second steel cord 41Y is electrically connected are the same (here, the fourth core metal 30d). On the other hand, in the second elastic crawler 11Y, the core metal 30 to which the one end 41a of the first steel cord 41X is electrically connected is different from the core metal 30 to which the one end 41a of the second steel cord 41Y is electrically connected. The core metal 30 to which the other end portions 41b of the first steel cord 41X and the second steel cord 41Y are connected may be other than the fourth core metal 30d.

[0066] In the second elastic crawler 11Y configured as described above, the first core metal 30a and the fourth core metal 30d are used as measurement terminals to measure the resistance between the core metals 30a and 30d, thereby making it possible to measure the resistance of the first steel cord 41X. In the second elastic crawler 11Y, the second core metal 30b and the fourth core metal 30d are used as measurement terminals to measure the resistance between the core metals 30b and 30d, thereby making it possible to measure the resistance of the second steel cord 41Y. Therefore, the second elastic crawler 11Y can detect which of the two steel cords 41X, 41Y has a break, thereby obtaining more detailed information about whether or not the steel cord 41 has a break. In this configuration, the core metals 30 that serve as measurement terminals are located at three locations: the first core metal 30a, the second core metal 30b, and the fourth core metal 30d. This means that fewer locations on the core metal 30 are used to measure resistance compared to the third elastic crawler 11Z, which will be described later. Therefore, with the second elastic crawler 11Y, there is less confusion about which core metal 30 to use for measurement compared to the third elastic crawler 11Z. In this respect, the second elastic crawler 11Y is superior to the third elastic crawler 11Z, which will be described later.

[0067] FIG. 10 shows a third elastic crawler 11Z, which is the elastic crawler 11 in which the connection of the one end 41a and the other end 41b to the core metal 30 is a third connection example.

[0068] In the third elastic crawler 11Z, one end 41a of the first steel cord 41X is connected to the first core metal 30a, and the other end 41b of the first steel cord 41X is connected to the fourth core metal 30d. Furthermore, in the third elastic crawler 11Z, one end 41a of the second steel cord 41Y is connected to the second core metal 30b, and the other end 41b of the second steel cord 41Y is connected to the third core metal 30c. In other words, in the third elastic crawler 11Z, one end 41a and the other end 41b of the first steel cord 41X and one end 41a and the other end 41b of the second steel cord 41Y are all electrically connected to different core metals 30.

[0069] In the third elastic crawler 11Z configured as described above, the first core metal 30a and the fourth core metal 30d are used as measurement terminals, and the resistance value between the core metals 30a and 30d is measured, thereby making it possible to measure the resistance value of the first steel cord 41X. Furthermore, in the third elastic crawler 11Z, the second core metal 30b and the third core metal 30c are used as measurement terminals, and the resistance value between the core metals 30b and 30c is measured, thereby making it possible to measure the resistance value of the second steel cord 41Y. Therefore, the third elastic crawler 11Z can detect which of the two steel cords 41X, 41Y has a break, and can obtain more detailed information about whether or not a break has occurred in the steel cord 41.

[0070] [Method for detecting breaks in steel cords in elastic crawlers] Here, we will explain a method for detecting a break in a steel cord 41 in an elastic crawler 11 having a steel cord 41 whose one end 41a is electrically connected to the first core wire 30a and whose other end 41b is electrically connected to the fourth core wire 30d.

[0071] As shown in Figure 11, breaks in the steel cords 41 that make up the elastic crawler 11 can be detected by a tester 50. The tester 50 includes a first lead rod 51 and a second lead rod 52. The tester 50 is a device that can measure the resistance value of a conductor connected between the first lead rod 51 and the second lead rod 52.

[0072] 11, when detecting whether or not the steel cord 41 is broken, the first lead rod 51 is brought into contact with the first core bar 30a, and the second lead rod 52 is brought into contact with the fourth core bar 30d, and the resistance value is measured using the tester 50. In order to easily identify the core bar 30 to be used as a measurement terminal, it is preferable to provide marks (such as engravings) on the exposed parts of the base 31 and protrusion 33 of the relevant core bar 30, the lug 17, the guide 18, etc. corresponding to that core bar 30.

[0073] The resistance value measured at this time is the resistance value of the conductor including the first core metal 30a, the steel cord 41, and the fourth core metal 30d. If a break occurs in the steel cord 41, the resistance value between the one end 41a and the other end 41b increases. Since the resistance values ​​of the first core metal 30a and the fourth core metal 30d usually do not change much, it can be assumed that a change in the detected resistance value is caused by a break in the steel cord 41. Therefore, the elastic crawler 11 can detect whether or not the steel cord 41 is broken based on the resistance value measured by the tester 50.

[0074] The user compares the resistance value measured by the above method with the resistance value when the elastic crawler 11 was new. If the measured resistance value has increased compared to the resistance value when the elastic crawler 11 was new, the user can determine that there is a break in the steel cord 41. Note that a predetermined threshold may be set for determining whether there is a break. In this case, the user determines that there is a break in the steel cord 41 if the difference between the measured resistance value and the resistance value when the elastic crawler 11 was new exceeds the predetermined threshold.

[0075] As described above, according to the present invention, it is possible to detect whether or not the steel cord 41 of the elastic crawler 11 has been broken.

[0076] (Effects of the embodiment) The elastic crawler 11 of this embodiment includes an endless crawler body 11a made of a rubber-like elastic material, a tension member 40 built into the crawler body 11a and wound around the circumferential direction of the crawler body 11a, and a plurality of core metals 30 built into the crawler body 11a and arranged at intervals around the circumferential direction of the crawler body 11a. The elastic crawler 11 is composed of a steel cord 41 around which the tension member 40 is wound spirally around the circumferential direction of the crawler body 11a. In the elastic crawler 11, the steel cord 41 is electrically connected to the plurality of core metals 30 only at one end 41a and the other end 41b in the longitudinal direction of the steel cord 41, and the one end 41a and the other end 41b are connected to different core metals 30 (a first core metal 30a and a fourth core metal 30d). With an elastic crawler 11 configured in this manner, a break in the steel cord 41 can be easily detected by measuring the resistance value between the first core wire 30a to which one end 41a is connected and the fourth core wire 30d to which the other end 41b is connected.

[0077] In the elastic crawler 11 of this embodiment (see Figure 6), the tension body 40 includes a steel cord group consisting of multiple (two in Figure 6) steel cords 41α, 41β as a unit, and one end 41a1, 41a2 of all the steel cords 41α, 41β included in the steel cord group are connected to the same core bar 30 (first core bar 30a), and the other end 41b1, 41b2 of all the steel cords 41α, 41β included in the steel cord group are connected to the same core bar 30 (fourth core bar 30d). According to the elastic crawler 11 having the above configuration, when the tension body 40 includes a group of steel cords, each group consisting of a plurality of steel cords 41, breakage of the steel cords 41 can be detected.

[0078] The first elastic crawler 11X (see Figure 8) has a first tension body 40X and a second tension body 40Y arranged side by side in the width direction of the crawler body 11a, and one end 41a of the first steel cord 41X that constitutes the first tension body 40X and one end 41a of the second steel cord 41Y that constitutes the second tension body Y are connected to the same core bar 30 (first core bar 30a), and the other end 41b of the first steel cord 41X and the other end 41b of the second steel cord 41Y are connected to the same core bar 30 (fourth core bar 30d). According to the first elastic crawler 11X having the above configuration, when the elastic crawler 11 includes two steel cords 41X, 41Y, breakage of the steel cords 41 can be easily detected.

[0079] In the second elastic crawler 11Y (see FIG. 9), the first tensile body 40X and the second tensile body 40Y are arranged side by side in the width direction of the crawler body 11a, and the other end 41B of the first steel cord 41X constituting the first tensile body 40X and the other end 41B of the second steel cord 41Y constituting the second tensile body 40Y are connected to the same core bar 30 (fourth core bar 30D). Alternatively, although not shown, the first elastic crawler 11Y may be configured such that one end 41a of the first steel cord 41X and one end 41a of the second steel cord 41Y are connected to the same core bar 30. According to the second elastic crawler 11Y having the above configuration, when the elastic crawler 11 includes two steel cords 41X, 41Y, when detecting a break in the steel cord 41, it is possible to determine which steel cord 41 has the break.

[0080] The third elastic crawler 11Z (see Figure 10) has a first tensile body 40X and a second tensile body 40Y arranged side by side in the width direction of the crawler body 11a, and one end 41a of the first steel cord 41X constituting the first tensile body 40X and one end 41a of the second steel cord 41Y constituting the second tensile body Y are connected to different cores 30 (the first core 30a and the second core 30b), and the other end 41b of the first steel cord 41X and the other end 41b of the second steel cord 41Y are connected to different cores 30 (the fourth core 30d and the third core 30c). According to the third elastic crawler 11Z having the above-described configuration, when the elastic crawler 11 includes two steel cords 41X, 41Y, when detecting a break in the steel cord 41, it is possible to determine which steel cord 41 has the break.

[0081] In the elastic crawler 11 of this embodiment, the core metals 30 (the first core metal 30a and the fourth core metal 30d) to which the one end portion 41a and the other end portion 41b are connected are partly exposed from the crawler body 11a. According to the elastic crawler 11 having the above-described configuration, the portion of the core wire 30 exposed from the crawler body 11a can be used as the portion to contact with the measuring instrument (lead rods 51, 52), thereby making it possible to easily measure the resistance value of the steel cord 41.

[0082] In the elastic crawler 11 of this embodiment, the core metals 30 (first core metal 30a and fourth core metal 30d) to which the one end portion 41a and the other end portion 41b are connected are adhered to the crawler body 11a with a conductive adhesive. The elastic crawler 11 having the above configuration can reliably ensure conductivity between the core metal 30 and the steel cord 41. This makes it possible to reliably measure the resistance value of the steel cord 41, and accurately detect breaks in the steel cord 41.

[0083] In the elastic crawler 11 of this embodiment (see FIG. 7(a)), the radial dimension D1 of one end 41a and the other end 41b of the steel cord 41 is larger than the radial dimension D0 of the portion other than the one end 41a and the other end 41b of the steel cord 41. According to the elastic crawler 11 configured as described above, the connection area of ​​the steel cord 41 with respect to the core metal 30 can be increased, thereby ensuring electrical conductivity between the steel cord 41 and the core metal 30.

[0084] In the elastic crawler 11 of this embodiment (see FIG. 7(b)), the radial dimension D2 of one end 41a and the other end 41b of the steel cord 41 is smaller than the radial dimension D0 of the portion other than the one end 41a and the other end 41b of the steel cord 41. According to the elastic crawler having the above-described configuration, rust that occurs on the core wire 30 is less likely to spread to the steel cord 41, thereby ensuring conductivity between the steel cord 41 and the core wire 30 for a long period of time.

[0085] In the elastic crawler 11 of this embodiment (see FIG. 7(c)), one end 41a and the other end 41b of the steel cord 41 are in direct contact with the core metal 30. According to the elastic crawler 11 having the above-described configuration, electrical conductivity between the steel cord 41 and the core metal 30 can be reliably ensured.

[0086] In the elastic crawler 11 of this embodiment (see Figure 7(a)), a coating portion 45 made of a conductive material is provided on one end 41a and the other end 41b of the steel cord 41, and the one end 41a and the other end 41b are electrically connected to the core wire 30 via the coating portion 45. According to the elastic crawler 11 having the above-described configuration, rust occurring on the core metal 30 can be made less likely to spread to the steel cord 41 .

[0087] The elastic crawler 11 of this embodiment (see FIG. 7(c)) has bent portions 47 at which one end 41a and the other end 41b of the steel cord 41 are bent toward the inner periphery of the crawler body 11a. According to the elastic crawler 11 having the above-described configuration, electrical conductivity between the steel cord 41 and the core metal 30 can be reliably ensured.

[0088] In the elastic crawler 11 (see FIG. 5) of this embodiment, the steel cord 41 includes a joint 41d made of a conductive material, which is arranged midway in the longitudinal direction. According to the elastic crawler 11 configured as described above, even when a plurality of steel cords 41 are joined together, it is possible to detect breaks in the steel cords 41. In the elastic crawler 11, the steel cords 41 can be configured using a plurality of steel cords that are short in the longitudinal direction.

[0089] The method for detecting a wire break in an elastic crawler 11 of this embodiment (see Figure 11) is a method for detecting a wire break in an elastic crawler 11 in which the tension body 40 is composed of a steel cord 41 wound spirally around the circumferential direction of the crawler body 11a, the steel cord 41 is electrically connected to multiple core wires 30 only at one end 41a and the other end 41b in the longitudinal direction of the steel cord 41, and the one end 41a and the other end 41b are connected to different core wires 30 (the first core wire 30a and the fourth core wire 30d), and the resistance value between one core wire 30 (the first core wire 30a) to which the one end 41a is connected and the other core wire 30 (the fourth core wire 30d) to which the other end 41b is connected is measured, and a wire break in the steel cord 41 is detected based on the resistance value. According to the method for detecting a broken wire in an elastic crawler 11 having such a configuration, a broken wire in the steel cord 41 can be easily detected by measuring the resistance value between the first core 30a to which one end 41a of the steel cord 41 is connected and the fourth core 30d to which the other end 41b of the steel cord 41 is connected.

[0090] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention described in the claims. [Explanation of symbols]

[0091] 11: Elastic crawler 11a: Crawler body 18:Protrusion 30: Core 30a: First core metal 30b:Second core metal 30c: Third core metal 30d: Fourth core metal 40: Tensile body 40X: First tensile body 40Y:Second tensile body 41: Steel cord 41X: Daiichi Steel Code 41Y: Second steel cord 41a: One end 41b: Other end 41d: Joint 45: Covering part

Claims

1. A crawler body made of a rubber-like elastic material and formed endlessly; a tension member built into the crawler body and wound around the crawler body in the circumferential direction; a plurality of core metals built into the crawler body and arranged at intervals in the circumferential direction of the crawler body; The tension body is formed of a steel cord wound spirally around the circumferential direction of the crawler body, the steel cord is electrically connected to the plurality of core metals only at one end and the other end in the longitudinal direction of the steel cord, The elastic crawler has one end and the other end connected to different core metals.

2. the tension member includes a steel cord group, each unit consisting of a plurality of the steel cords, 2. The elastic crawler according to claim 1, wherein the one ends of all the steel cords included in the steel cord group are connected to the same core bar, and the other ends of all the steel cords included in the steel cord group are connected to the same core bar.

3. The first tension body and the second tension body are arranged side by side in the width direction of the crawler body, 3. An elastic crawler as described in claim 1 or claim 2, wherein one end of the first steel cord constituting the first tension body and one end of the second steel cord constituting the second tension body are connected to the same core bar, and the other end of the first steel cord and the other end of the second steel cord are connected to the same core bar.

4. The first tension body and the second tension body are arranged side by side in the width direction of the crawler body, An elastic crawler as described in claim 1 or claim 2, wherein one end of the first steel cord constituting the first tension body and one end of the second steel cord constituting the second tension body are connected to the same core bar, or the other end of the first steel cord and the other end of the second steel cord are connected to the same core bar.

5. The first tension body and the second tension body are arranged side by side in the width direction of the crawler body, 3. An elastic crawler according to claim 1, wherein one end of the first steel cord constituting the first tension body and one end of the second steel cord constituting the second tension body are connected to different core wires, and the other end of the first steel cord and the other end of the second steel cord are connected to different core wires.

6. The elastic crawler according to any one of claims 1 to 5, wherein a part of the core metal to which the one end and the other end are connected is exposed from the crawler body.

7. The elastic crawler according to any one of claims 1 to 6, wherein the core metal to which the one end and the other end are connected is adhered to the crawler body with a conductive adhesive.

8. The elastic crawler according to any one of claims 1 to 7, wherein the radial dimensions of the one end and the other end of the steel cord are larger than the radial dimensions of a portion of the steel cord other than the one end and the other end.

9. The elastic crawler according to any one of claims 1 to 7, wherein the radial dimensions of the one end and the other end of the steel cord are smaller than the radial dimensions of a portion of the steel cord other than the one end and the other end.

10. The elastic crawler according to any one of claims 1 to 7, wherein the one end and the other end of the steel cord are in direct contact with the core metal.

11. An elastic crawler as described in any one of claims 1 to 7, wherein a covering portion made of a conductive material is provided on the one end and the other end of the steel cord, and the one end and the other end are electrically connected to the core via the covering portion.

12. The elastic crawler according to any one of claims 1 to 7, wherein the one end and the other end of the steel cord are bent toward an inner periphery of the crawler body.

13. The elastic crawler according to any one of claims 1 to 12, wherein the steel cord includes a joint made of a conductive material and arranged midway along the length of the steel cord.

14. A crawler body made of a rubber-like elastic material and formed endlessly; a tension member built into the crawler body and wound around the crawler body in the circumferential direction; a plurality of core metals built into the crawler body and arranged at intervals in the circumferential direction of the crawler body; the tension body is made of a steel cord wound spirally around the circumferential direction of the crawler body, the steel cord is electrically connected to the plurality of core metals only at one end and the other end in the longitudinal direction of the steel cord, A method for detecting a break in an elastic crawler, the one end and the other end of which are connected to different core metals, comprising: A method for detecting a break in an elastic crawler, which measures the resistance value between one of the core wires to which the one end is connected and the other of the core wires to which the other end is connected, and detects a break in the steel cord based on the resistance value.

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