JP2013256250A - Elastic crawler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastic crawler which makes the bending when being wound around a driving wheel or an idling wheel more even, in the elastic crawler having a main cord layer of a superposition structure.SOLUTION: A rubber crawler 10 (one example of an elastic crawler) includes: a rubber belt 12 (one example of an elastic body); a plurality of lugs 14 arranged on an outer circumference of the rubber belt 12 at an interval in the crawler circumferential direction; a main cord layer 30 which is embedded in the rubber belt 12, is extended in the crawler circumferential direction, wherein one end 30A side is superposed on the other end 30B side from the crawler outer circumferential side to form an superposition part 34 and, at the same time, one end 30A is arranged within a lug region R of the rubber belt 12 corresponding to the lug 14; and a reinforcement cord layer 36 which is embedded in the rubber belt 12, has a bending rigidity lower than the main cord layer 30 and is extended to the superposition part 34 beyond the one end 30A of the main cord layer 30, wherein a superposition part P, which is superposed in the crawler thickness direction with respect to the superposition part 34, is arranged within the same lug region R as the one end 30A.

Description

  The present invention relates to an elastic crawler.

  Usually, a steel cord layer (main cord layer) as a tensile member is disposed inside the rubber crawler. As the steel cord layer, a structure in which steel cords extending in the crawler circumferential direction are arranged in the crawler width direction and both end portions in the crawler circumferential direction are overlapped is known (for example, Patent Document 1).

JP 09-109948 A

  By the way, the steel cord layer of the overlapping structure has higher bending rigidity of the overlapping portion than the other portions, so when the overlapping portion wraps around the drive wheel or idler wheel, Large bending tends to occur at the boundary (the end of the steel cord layer). In particular, the end portion of the steel cord layer positioned on the crawler outer peripheral side of the overlapping portion tends to be easily bent as compared with the end portion of the steel cord layer positioned on the crawler inner peripheral side. When a large bend occurs in the steel cord layer, the rubber crawler also causes a large bend in a portion corresponding to the portion where the large bend of the steel cord layer occurs. As a result, tensile strain generated in rubber around the end of the steel cord layer or rubber on the surface of the rubber crawler corresponding to the end increases, and there is a risk that durability of the crawler may be reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to make the bending of a resilient crawler having a main cord layer with a superposed structure evenly wound around a driving wheel or idler wheel.

  An elastic crawler according to a first aspect of the present invention includes an endless belt-like elastic body, a plurality of lugs arranged on the outer circumference of the elastic body at intervals in the circumferential direction of the elastic body, and projecting toward the outer circumference of the elastic body, Embedded in the elastic body and extending in the circumferential direction of the elastic body, one end side in the circumferential direction of the elastic body is overlapped with the other end side from the outer circumferential side of the elastic body to form an overlapping portion where the one end side and the other end side are overlapped. And the main cord layer disposed in the lug region of the elastic body corresponding to the lug, and the one end of the main cord layer embedded in the elastic body and having a lower bending rigidity than the main cord layer. And a reinforcing cord layer disposed in the lug region that is the same as the one end. The reinforcing cord layer extends to the overlapping portion and overlaps the overlapping portion in the elastic body thickness direction.

  In the elastic crawler according to claim 1 of the present invention, since the reinforcing cord layer extends beyond the one end of the main cord layer to the overlapping portion, when the main cord is wound around the driving wheel or idler wheel, It is possible to suppress a large bending from occurring at one end of the layer.

  In addition, since the bending rigidity of the reinforcing cord layer is lower than that of the main cord layer, the end portion of the reinforcing cord layer (end portion in the circumferential direction of the elastic body) is placed when it is wound around the drive wheel or idle wheel. It can suppress that a big bending arises as a starting point.

  Since the overlapping portion of the main cord layer and the reinforcing cord layer overlap with each other in the elastic lug region where one end of the main cord layer is arranged, the reinforcing cord is disposed on the entire overlapping portion, for example. Since the bending rigidity of the entire overlapping portion is not excessively increased as compared with the case where the layers are overlapped, it is possible to suppress the occurrence of a large bend starting from one end and the other end of the main cord layer.

  From the above, according to the elastic crawler of the first aspect, it is possible to make the bend when it is wound around the drive wheel or the idler wheel evenly.

  An elastic crawler according to a second aspect of the present invention is the elastic crawler according to the first aspect, wherein the main cord layer is configured by arranging main cords extending in a circumferential direction of the elastic body in the elastic body width direction, and the reinforcing cord. The layer is formed by arranging reinforcing cords extending in the circumferential direction of the elastic body in the elastic body width direction.

In the elastic crawler according to claim 2 of the present invention, by extending the main cord in the circumferential direction of the elastic body, it is possible to suppress a lateral shift during crawler traveling caused by the inclination of the main cord.
On the other hand, by extending the reinforcing cord in the circumferential direction of the elastic body, the bending rigidity of the reinforcing cord layer can be effectively improved, and the occurrence of large bending at one end of the main cord layer can be further suppressed.

  The elastic crawler according to claim 3 of the present invention is the elastic crawler according to claim 2, wherein the reinforcing cord is a steel cord made of the same material as the main cord and having a smaller diameter than the main cord.

In the elastic crawler according to claim 3 of the present invention, since the main cord and the reinforcing cord are made of steel cords having excellent tensile strength, durability is improved.
On the other hand, since the reinforcing cord has a smaller diameter than the main cord, it is possible to sufficiently secure the thickness of the elastic body from the reinforcing cord layer to the outer peripheral surface of the elastic body.

  The elastic crawler according to a fourth aspect of the present invention is the elastic crawler according to any one of the first to third aspects, wherein the reinforcing cord layer is overlapped on an outer peripheral side of the elastic body of the main cord layer, and is elastic. An end portion in the body circumferential direction is disposed between the one end side and the other end side that form the overlapping portion of the main cord layer.

  In the elastic crawler according to claim 4 of the present invention, the reinforcing cord layer is disposed on the outer peripheral side of the elastic body on the other end side of the main cord layer, and the end portion (end portion in the elastic body circumferential direction) of the reinforcing cord layer is provided. The reinforcing cord layer can be disposed by a simple process of overlapping one end side and the other end side of the main cord layer so as to be sandwiched between them.

  The elastic crawler according to claim 5 of the present invention is the elastic crawler according to any one of claims 1 to 3, wherein the reinforcing cord layer is overlapped on an outer peripheral side of the elastic body of the main cord layer, and is elastic. An end portion in the body circumferential direction is disposed on the elastic body outer peripheral side of the overlapping portion of the main cord layer.

  In the elastic crawler according to the fifth aspect of the present invention, the reinforcing cord layer is overlaid on the outer circumference side of the elastic body of the main cord layer, and the end portion (end portion in the circumferential direction of the elastic body) of the reinforcing cord layer is placed on the main cord layer. Since one end of the main cord layer is covered with the reinforcing cord layer from the outer circumference side of the elastic body because it is disposed on the outer circumference side of the elastic body of the overlapping portion. Thereby, the effect which suppresses that a big bending arises from the end of the main cord layer at the time of being wound around a drive wheel or an idle wheel further improves.

  As described above, the elastic crawler of the present invention can make the bending when it is wound around the drive wheel or idler wheel closer to uniform.

It is the side view which looked at the rubber crawler of a 1st embodiment from the side (crawler width direction). It is a top view which shows the inner peripheral side of the rubber crawler of 1st Embodiment. It is the 3X-3X sectional view taken on the line of FIG. 2 of the rubber crawler of 1st Embodiment. (A) It is the 4X-4X sectional view taken on the line of FIG. 2 of the rubber crawler of 1st Embodiment. (B) It is the 4B-4B sectional view taken on the line of FIG. 4 (A) of the rubber crawler of 1st Embodiment. It is a sectional side view of the rubber crawler for demonstrating the state by which the rubber crawler of 1st Embodiment was wound around the sprocket (corresponding to the 4X-4X sectional view taken on the line of FIG. 2). (A) It is the 4X-4X sectional view taken on the line of FIG. 2 of the rubber crawler of 2nd Embodiment. (B) It is the 6B-6B sectional view taken on the line of the rubber crawler of 2nd Embodiment of FIG. 6 (A). It is a sectional side view of the rubber crawler for demonstrating the state by which the rubber crawler of 2nd Embodiment was wound on the sprocket (corresponding to the 4X-4X sectional view taken on the line of FIG. 2). It is a sectional side view of the rubber crawler structural member for demonstrating the state before connecting the both ends of the rubber crawler structural member of the rubber crawler of 2nd Embodiment.

(First embodiment)
The elastic crawler according to the first embodiment of the present invention will be described below.

  As shown in FIG. 1, an endless rubber crawler 10 as an example of an elastic crawler according to the first embodiment includes a sprocket 100 as an example of a drive wheel coupled to a drive shaft of a crawler vehicle as a machine body, and a crawler. It is used by being wound around an idler 102 as an example of an idler wheel rotatably attached to a car. In addition, a plurality of rolling wheels 104 (see FIG. 1) that are disposed between the sprocket 100 and the idler 102 and are rotatably attached to the crawler wheel roll on the inner periphery of the rubber crawler 10.

In the present embodiment, the circumferential direction of the endless rubber crawler 10 (direction of arrow S in FIG. 2) is referred to as “crawler circumferential direction”, and the width direction of rubber crawler 10 (in the direction of arrow W in FIG. 2) "Direction". The crawler circumferential direction and the crawler width direction are orthogonal to each other when the rubber crawler 10 is viewed from the inner circumferential side or the outer circumferential side.
Further, in this embodiment, the inner peripheral side (the arrow IN direction side in FIGS. 3 and 4A) of the rubber crawler 10 that is wound around the sprocket 100, the idler 102, and the wheel 104 is an “crawler”. "Inner peripheral side" and the outer peripheral side of rubber crawler 10 (the arrow OUT direction side in Figs. 3 and 4A) is referred to as "crawler outer peripheral side". 3 and 4A, the arrow IN direction (annular inner direction) and the arrow OUT direction (annular outer direction) indicate the inner and outer directions of the rubber crawler 10 in the wound state.
In this embodiment, the rubber crawler 10 is wound around the sprocket 100 and the idler 102. However, the present invention is not limited to this configuration, and depending on the arrangement of the sprocket 100, the idler 102, and the plurality of wheel 104. In addition to the sprocket 100 and the idler 102, the rubber crawler 10 may be wound around one or a plurality of rollers 104. In addition to the above, the rubber crawler may be attached to one or a plurality of idlers separately from the idler 102. 10 may be wound around.

  Further, the sprocket 100, the idler 102, the wheels 104, and the rubber crawler 10 wound around them constitute a crawler traveling device 90 (see FIG. 1) as a traveling unit of the crawler vehicle.

  As shown in FIG. 1, the sprocket 100 is formed by forming tooth portions 100B at regular intervals in the circumferential direction on the outer peripheral surface of a disc-shaped ring portion 100A connected to a drive shaft of a crawler wheel. The sprocket 100 causes the rubber crawler 10 to circulate between the sprocket 100 and the idler 102 by applying a driving force from the crawler wheel to the rubber crawler 10 (details will be described later).

  The idler 102 has a disk shape and is rotatably attached to the crawler wheel. The idler 102 is pressed in a direction away from the sprocket 100 by a pressure mechanism such as hydraulic pressure (not shown) provided on the crawler vehicle side, and holds the tension (tension) of the rubber crawler 10.

  The wheel 104 supports the weight of the crawler wheel, and includes a shaft portion 104A that is rotatably attached to the crawler wheel, and a wheel portion 104B that is a flange portion that projects from both ends of the shaft portion 104A to the outer peripheral side. , Including.

  The idler 102 and the wheel 104 are driven to rotate with respect to the rubber crawler 10 circulating between the sprocket 100 and the idler 102.

  As shown in FIG. 1, the rubber crawler 10 has a rubber belt 12 in which a rubber material is formed in an endless belt shape. In addition, the rubber belt 12 of this embodiment is an example of the endless elastic body of the present invention. In addition, the circumferential direction, the width direction, the inner circumferential side, and the outer circumferential side of the rubber belt 12 of the present embodiment coincide with the crawler circumferential direction, the crawler width direction, the crawler inner circumferential side, and the crawler outer circumferential side, respectively.

  As shown in FIG. 2, a plurality of core bars 20 are embedded in the rubber belt 12 at intervals in the circumferential direction of the crawler (a constant interval in this embodiment). In addition, the cored bar 20 of this embodiment is formed with the metal material.

  As shown in FIG. 3, the cored bar 20 includes a cored bar central part 22 and a pair of cored bar blade parts 24 extending outward from the both ends of the cored bar central part 22 in the crawler width direction. The cored bar wing part 24 includes a cored bar projection 26 that projects from the base side (the base part in the present embodiment) to the inner peripheral side of the crawler.

  The cored bar central part 22 is a part that receives a load and driving force from the sprocket 100, and is therefore thicker in the crawler inside and outside than the cored bar blade part 24. Moreover, although the core metal center part 22 of this embodiment is completely embedded in the rubber belt 12, the present invention is not limited to this configuration, and the surface on the crawler inner peripheral side of the metal core center part 22 is a rubber belt. The 12 inner peripheral surfaces 12A may be exposed.

  The core metal protrusion 26 protrudes from the inner peripheral surface 12 </ b> A of the rubber belt 12 at the protruding tip end side. The protruding portion of the cored bar protrusion 26 is rubber-coated with the same rubber material as the rubber belt 12. In addition, this invention is not limited to the said structure, About the protrusion part of the metal core protrusion 26, the structure which is not covered with rubber | gum, or the structure which a part exposes without rubber | gum covering may be sufficient.

  In the rubber crawler 10, the sprocket 100 and the idler 102 roll between the pair of core metal protrusions 26 of the rubber belt 12, in other words, on the core metal central portion 22. The pair of cored bar protrusions 26 can abut the sprocket 100 and the idler 102 to restrict the movement of the sprocket 100 and the idler 102 in the crawler width direction. In other words, the cored bar protrusion 26 can abut against the sprocket 100 and the idler 102 to suppress relative displacement in the crawler width direction between the sprocket 100 and the idler 102 and the rubber crawler 10 (rubber belt 12).

  Further, in the present embodiment, as shown in FIG. 2, a straight line passing through the center in the crawler width direction of the central portion 22 of the core metal 20 and a straight line passing through the center in the crawler width direction of the rubber belt 12 (hereinafter referred to as the center). The line CL). In addition, this invention is not limited to this structure, The straight line which passes along the center of the crawler width direction of the metal core center part 22 of the metal core 20 with respect to the center line CL of the rubber belt 12 may be shifted in the crawler width direction.

  In the present embodiment, the side toward the center line CL is described as the inside in the crawler width direction, and the side away from the center line CL is described as the outside in the crawler width direction.

  As shown in FIGS. 2 and 3, rolling wheel rolling surfaces 16 extending along the crawler circumferential direction are formed on both sides in the crawler width direction with the pair of core metal protrusions 26 of the rubber belt 12 interposed therebetween. The roller rolling surface 16 is flat and constitutes a part of the inner peripheral surface 12A of the rubber belt 12.

  As shown in FIG. 2, an engagement recess 40 in which the tooth portion 100 </ b> B of the sprocket 100 is inserted and engaged between the core metal central portions 22 of the metal cores 20 adjacent to each other in the crawler circumferential direction is provided on the inner periphery of the rubber belt 12. Is formed. In addition, this invention is not limited to this structure, Instead of the engagement recessed part 40, the rubber belt 12 forms the through-hole which penetrates the rubber belt 12 inside and outside a crawler, and inserts and engages the tooth | gear part 100B in this through-hole. Also good. Moreover, you may form the slit etc. which penetrate the crawler inside and outside in the bottom part of the said engagement recessed part 40. FIG.

  Here, when the sprocket 100 rotates (drives) in a state where the tooth portion 100 </ b> B of the sprocket 100 is inserted and engaged with the engagement recess 40, a driving force is applied to the core metal central portion 22 of the core metal 20 via the engagement recess 40. The driving force is transmitted to the rubber belt 12 (rubber crawler 10).

Further, as shown in FIG. 1, a plurality of lugs 14 that protrude toward the outer periphery of the crawler are disposed on the outer periphery of the rubber belt 12 at intervals in the crawler peripheral direction. The lug 14 is formed of a rubber material and is a part that contacts the ground. Further, as shown in FIG. 3, the lugs 14 are arranged symmetrically with respect to the center line CL. Moreover, the lug 14 has overlapped with the metal core 20 and the crawler inside / outside direction, as shown to FIG. 4 (A). In other words, the lug 14 and the cored bar 20 overlap each other when viewed from the outer peripheral side of the crawler.
In addition, this invention is not limited to this structure, You may use a conventionally well-known thing about the arrangement position and shape of a lug.
Further, the “inner / outer direction” here is synonymous with the “crawler thickness direction”.

  As shown in FIG. 2, main cord layers 30 extending along the crawler circumferential direction are respectively embedded in the rubber belt 12 on the crawler outer circumferential side of the pair of cored bar blade portions 24. The main cord layer 30 is configured by arranging main cords 32 extending in the crawler circumferential direction in the crawler width direction.

The main cord layer 30 makes a round in the rubber belt 12, and as shown in FIG. 4A, both end portions are overlapped in the crawler thickness direction. Specifically, one end 30A side in the crawler circumferential direction of the main cord layer 30 is overlapped with the other end 30B side from the crawler outer peripheral side. The one end 30A side of the main cord layer 30 is overlapped and joined to the other end 30B side through a rubber material.
Hereinafter, a portion where the one end 30 </ b> A side and the other end 30 </ b> B side of the main cord layer 30 are overlapped will be described as the overlapping portion 34.

In the present embodiment, the overlapping portion 34 of the main cord layer 30 straddles a plurality (three) of the core bars 20 and a plurality (three) of the lugs 14. Further, one end 30 </ b> A and the other end 30 </ b> B of the main cord layer 30 are disposed in the lug region R of the rubber belt 12 corresponding to the separate lugs 14.
The “lug region R” here refers to a region corresponding to the lug 14 of the rubber belt 12, that is, a region of the rubber belt 12 that overlaps the lug 14 when viewed from the outer periphery of the crawler. ) Indicates a region of the rubber belt 12 corresponding to the length (range) between the roots Z of one lug 14. In addition, when the side wall surface of the lug 14 is linearly inclined, the root Z of the lug 14 indicates the intersection of the straight side wall surface and the flat outer peripheral surface of the rubber belt 12. Indicates the intersection (inflection point) between the curved side wall surface and the outer peripheral surface of the rubber belt 12, and the base side of the side wall surfaces of the lugs 14 adjacent to each other in the crawler circumferential direction are curved. In addition, when adjacent to each other, the lugs 14 adjacent to each other indicate the thinnest point where the rubber thickness is the thinnest.

  Further, as shown in FIG. 2, the main cord 32 of the present embodiment extends linearly in parallel with the center line CL. In addition, this invention is not limited to the said structure, The main cord 32 may incline in the range of about +/- 10 degree with respect to the center line CL.

  In the present embodiment, a steel cord having excellent tensile strength is used as the main cord 32. Note that the present invention is not limited to this configuration, and an organic layer made of organic fibers (for example, nylon fibers, aromatic polyamide fibers) can be used as long as sufficient tensile strength and bending rigidity as the main cord layer 30 can be secured. A fiber cord may be used as the main cord.

As shown in FIG. 4A, a reinforcing cord layer 36 extending in the crawler circumferential direction toward the overlapping portion 34 beyond the one end 30A of the main cord layer 30 is embedded in the rubber belt 12. With this configuration, the reinforcing cord layer 36 overlaps the overlapping portion 34 of the main cord layer 30 in the crawler thickness direction. In other words, when the rubber crawler 10 is viewed from the crawler outer peripheral side, a part of the reinforcing cord layer 36 overlaps the overlapping portion 34.
Hereinafter, a portion where the reinforcing cord layer 36 overlaps the overlapping portion 34 of the main cord layer 30 will be described as an overlapping portion P.

  The reinforcing cord layer 36 is configured by arranging a plurality of reinforcing cords 38 extending along the crawler circumferential direction or extending obliquely with respect to the crawler circumferential direction so as to be parallel to each other. In the present embodiment, the reinforcing cord 38 extends linearly in parallel with the center line CL. In addition, this invention is not limited to the said structure, The reinforcement cord 38 may incline in the range about about +/- 10 degree with respect to the center line CL.

Further, the reinforcing cord layer 36 is overlaid on the outer side of the crawler of the main cord layer 30 (specifically, over the rubber material (see FIG. 4B)), and the one end 30A of the main cord layer 30 ( The left end portion in FIG. 4A is covered from the crawler outer peripheral side.
Specifically, in the present embodiment, one end 36A of the reinforcing cord layer 36 (the left end portion in FIG. 4A) is adjacent to the lug region R where the one end 30A of the main cord layer 30 is disposed. The other end 36 </ b> B (the right end portion in FIG. 4A) is disposed in the lug region R and is disposed in the same lug region R as the one end 30 </ b> A of the main cord layer 30. That is, one end 30 </ b> A of the main cord layer 30 and the overlapping portion P of the reinforcing cord layer 36 are arranged in the same lug region R. In other words, as viewed from the outer periphery of the crawler, the entire end portion 30A of the main cord layer 30 and the overlapping portion P of the reinforcing cord layer 36 overlap the same lug 14.

  Further, the reinforcing cord layer 36 is set so that the width along the crawler width direction is wider than or equal to the width of the main cord layer 30 along the crawler width direction.

  As shown in FIG. 4B, in this embodiment, in the overlapping portion 34, one end side and the other end side of the main cord 32 overlap in the crawler thickness direction, and the main cord 32 is reinforced on the crawler outer peripheral side. The cord 38 overlaps the crawler thickness direction. However, the present invention is not limited to this configuration. In the overlapping portion 34, one end side and the other end side of the main cord 32 are shifted in the crawler width direction and do not overlap in the crawler thickness direction, one end side of the main cord 32, or the like. The end side and the reinforcing cord 38 may be displaced in the crawler width direction so as not to overlap in the crawler thickness direction.

  Further, the reinforcing cord layer 36 has a bending rigidity lower than that of the main cord layer 30 when wound around the sprocket 100 or the idler 102.

  The reinforcing cord 38 of the present embodiment uses a steel cord having a smaller diameter (and a smaller cross-sectional area) than the main cord 32 formed of the same material as the main cord 32. That is, in this embodiment, the bending rigidity of the reinforcing cord 38 is lower than that of the main cord 32. The present invention is not limited to this configuration, and an organic layer composed of organic fibers (for example, nylon fibers, aromatic polyamide fibers, etc.) can be used as long as sufficient tensile strength and bending rigidity as the reinforcing cord layer 36 can be secured. A fiber cord may be used as the main cord.

Next, the effect of the rubber crawler 10 of this embodiment is demonstrated.
In the rubber crawler 10, the reinforcing cord layer 36 extends beyond the one end 30A of the main cord layer 30 to the overlapping portion 34 in the crawler circumferential direction, so that the bending rigidity around the one end 30A of the main cord layer 30 is improved. When it is wound around the sprocket 100 or the idler 102, it is possible to suppress the occurrence of a large bend from the one end 30A of the main cord layer 30 as a starting point.

  Further, by making the bending rigidity of the reinforcing cord layer 36 lower than that of the main cord layer 30, when it is wound around the sprocket 100 or the idler 102, a large bending starts from the one end 36 </ b> A and the other end 36 </ b> B of the reinforcing cord layer 36. It can be suppressed from occurring.

Since the overlapping portion P where the overlapping portion 34 of the main cord layer 30 and the reinforcing cord layer 36 overlap is disposed in the same lug region R where the one end 30A of the main cord layer 30 is disposed, Since the bending rigidity of the entire mating portion 34 is not excessively increased, it is possible to suppress the occurrence of a large bend from the one end 30A and the other end 30B of the main cord layer 30 as starting points.
In addition, by arranging the other end 36B of the reinforcing cord layer 36 in the lug region R corresponding to the lug 14, when the cord is wound around the sprocket 100 or the idler 102, It is possible to alleviate the concentration of strain on the rubber.

From the above, according to the rubber crawler 10, it is possible to make the bending when wound around the sprocket 100 or the idler 102 uniform.
Thereby, when it is wound around the sprocket 100 or the idler 102, it is possible to suppress the occurrence of excessive tensile strain on the outer periphery of the rubber crawler 10.
In the present embodiment, the tensile strain tends to concentrate on the roots Z1 and Z2 (see FIG. 5) of the lug 14 corresponding to the lug region R where the overlapping portion P is arranged. (Reinforcement cord layer 36) suppresses concentration of tensile strain.

Further, in the rubber crawler 10, by extending the main cord 32 in the crawler circumferential direction, it is possible to suppress a lateral shift during crawler traveling due to the inclination of the main cord 32.
On the other hand, by extending the reinforcing cord 38 in the crawler circumferential direction, the bending rigidity of the reinforcing cord layer 36 can be effectively improved, and the occurrence of large bending at one end 30A of the main cord layer 30 can be further suppressed. it can.

  Further, in the rubber crawler 10, since one end 30A of the main cord layer 30 is covered with the reinforcing cord layer 36 from the outer periphery side of the crawler, when the rubber cord is wound around the sprocket 100 or the idler 102, one end 30A of the main cord layer 30 is provided. As a starting point, it is possible to effectively suppress the occurrence of large bending. Even if a crack is generated from one end 30 </ b> A of the main cord layer 30 by repeated winding, the progress of the crack is suppressed by the reinforcing cord layer 36.

And in the rubber crawler 10, since the main cord 32 and the reinforcement cord 38 are made into the steel cord which is excellent in tensile strength, durability improves.
On the other hand, since the diameter of the reinforcing cord 38 is smaller than that of the main cord 32, a sufficient rubber thickness from the reinforcing cord layer 36 to the outer peripheral surface of the rubber belt 12 can be secured. Thereby, even if the outer peripheral surface of the rubber belt 12 is scratched, it is possible to secure a time until the scratch reaches the main cord 32.

(Second Embodiment)
Next, a rubber crawler according to a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIGS. 6A and 6B, the rubber crawler 50 of this embodiment has the same configuration as the rubber crawler 10 of the first embodiment except for the position where the reinforcing cord layer 52 is disposed. is there. For this reason, below, the position where the reinforcement cord layer 52 is arrange | positioned is demonstrated. The configuration of the reinforcing cord layer 52 of this embodiment (excluding the arrangement position) is the same as the configuration of the reinforcing cord layer 36 of the first embodiment, and the reinforcing cord 54 constituting the reinforcing cord layer 52 is: This corresponds to the reinforcing cord 38 of the first embodiment.

  As shown in FIG. 6A, the reinforcing cord layer 52 is overlaid on the crawler outer peripheral side of the main cord layer 30, and the other end 52B side is at one end 30A side and the other end 30B of the overlapping portion 34 of the main cord layer 30. (See FIG. 6B). That is, the other end 52B of the reinforcing cord layer 52 is sandwiched between the one end 30A side and the other end 30B side of the overlapping portion 34. On the other hand, one end 52A (the left end in FIG. 6A) of the reinforcing cord layer 52 is disposed in the lug region R adjacent to the lug region R in which the one end 30A of the main cord layer 30 is disposed. .

Next, the manufacturing method of the rubber crawler 50 of this embodiment is demonstrated.
As shown in FIG. 8, an endless rubber crawler constituting member 51 before forming the endless rubber crawler 50 is formed.

  This rubber crawler constituting member 51 is formed in a long vulcanizing mold, a belt-shaped unvulcanized rubber material constituting the crawler inner peripheral portion of the rubber belt 12, a core metal 20, and an unvulcanized long belt-shaped rubber material. The buried main cord layer 30, the reinforcing cord layer 52 buried in the unvulcanized belt-shaped rubber material, the belt-shaped unvulcanized rubber material constituting the crawler outer peripheral portion of the rubber belt 12, and the unvulcanized rubber to be the lug 14 It is formed by stacking in the order of lump and vulcanizing. In addition, about the arrangement | positioning order of each member in the mold for vulcanization, you may change variously.

  As shown in FIG. 8, the endless rubber crawler 50 is formed by overlapping and joining one end 51A and the other end 51B of the rubber crawler constituting member 51 in the longitudinal direction. Specifically, the one end 51A and the other end 51B of the rubber crawler constituting member 51 are left in an unvulcanized or semi-vulcanized state when the main body is vulcanized, and the one end 51A and the other end 51B are overlapped and vulcanized. Thus, the one end 51A and the other end 51B are vulcanized and bonded.

Next, the effect of the rubber crawler 50 of this embodiment is demonstrated.
In addition, about the effect similar to 1st Embodiment among the effects of this embodiment, the description is abbreviate | omitted suitably.

  In the rubber crawler 50, one end of the main cord layer 30 is disposed such that the reinforcing cord layer 36 is disposed on the crawler outer peripheral side on the other end 30 </ b> B side of the main cord layer 30 and the other end 52 </ b> B of the reinforcing cord layer 52 is sandwiched therebetween. The reinforcing cord layer 36 can be disposed between the one end 30A side and the other end 30B side by a simple process of overlapping the 30A side and the other end 30B side.

  The rubber crawler according to the first and second embodiments is a rubber crawler for an airframe having a sprocket 100 and an idler 102. It is good also as a rubber crawler for the body which has. As such a rubber crawler for an airframe, for example, there is one that transmits a driving force by a frictional force between a drive wheel and a rubber crawler. In such a friction drive type rubber crawler, the rubber belt 12 is not provided with a metal core and an engagement concave portion, but instead, a rubber protrusion protruding toward the inner side of the crawler at the center in the crawler width direction is spaced apart in the crawler circumferential direction. The rubber protrusion is provided with both sides of the rubber protrusion as a rolling surface on which the drive wheel and idler wheel roll.

  Further, in the first and second embodiments, the cored bar 20 is formed of a metal material, but the present invention is not limited to this configuration, and if it has sufficient strength with respect to the specifications of the rubber crawler 10, For example, the cored bar 20 may be formed of a resin material.

  In the first and second embodiments, the rubber belt 12 formed of a rubber material is used as the endless elastic body. However, the present invention is not limited to this configuration, and an elastic body having rubber elasticity ( For example, an elastomer belt formed of an elastomer that is a resin material having rubber elasticity may be used.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

(Test example)
In order to confirm the effect of the present invention, a rubber crawler of an example included in the present invention and a rubber crawler of a comparative example not included in the present invention were tested as follows. The test crawler of the same size was used for the test.

<Test rubber crawler>
Example: A rubber crawler having the same structure as that of the second embodiment.
Comparative example: A rubber crawler having a structure in which the reinforcing cord layer is removed from the rubber crawler according to the second embodiment.
Note that a steel cord having a breaking strength of 3.92 kN was used as the main cord 32 of the test rubber crawler, and a steel cord having a breaking strength of 1.47 kN was used as the reinforcing cord 54.

<Test method>
A disk-like body (wheel) was pressed against the portion corresponding to the overlapping portion 34 of the test rubber crawler with a force of 20 kN from the inner peripheral side of the crawler, and the test rubber crawler was bent along the outer circumference of the disc-like body. . And FEM analysis was performed about the tensile strain which acts on the roots Z1 and Z2 vicinity (refer FIG. 7) of the lug 14 corresponding to the lug area | region R in which the end 30A of the main cord layer 30 was arrange | positioned in this bending state.
For the rubber crawler of the example, FEM analysis is also performed on tensile strain acting on the bases Z3 and Z4 of the lug 14 corresponding to the lug region R where the one end 36A of the reinforcing cord layer 36 is disposed (see FIG. 7). went. The results are shown in Table 1. As for the strain value, the smaller the value, the better the result.

  As can be seen from Table 1, in the rubber crawler of the example included in the present invention, it can be seen that the tensile strain in the vicinity of the root Z2 is suppressed as compared with the rubber crawler of the comparative example. Moreover, since the difference of the distortion value of root Z1-Z4 is small in an Example, it turns out that the bending of the rubber crawler at the time of being wound around a drive wheel or an idle wheel is approaching uniformly.

10, 50 Rubber crawler (elastic crawler)
12 Rubber belt (endless elastic body)
14 Lug 30 Main cord layer 30A One end 30B Other end 32 Main cord 34 Superposed portion 36 Reinforcement cord layer 38 Reinforcement cord 52 Reinforcement cord layer 54 Reinforcement cord P Overlapping portion R Lag region CL Center line S Crawler circumferential direction (elastic body circumferential direction) )
W Crawler width direction (elastic body width direction)
IN crawler inner peripheral side (elastic inner peripheral side)
OUT crawler outer peripheral side (elastic body outer peripheral side)

Claims (5)

An endless belt-like elastic body,
A plurality of lugs arranged on the outer circumference of the elastic body at intervals in the circumferential direction of the elastic body and projecting toward the outer circumference of the elastic body;
Embedded in the elastic body and extending in the circumferential direction of the elastic body, one end side in the circumferential direction of the elastic body is overlapped with the other end side from the outer circumferential side of the elastic body to form an overlapping portion where the one end side and the other end side are overlapped. And the main cord layer arranged in the lug region of the elastic body corresponding to the lug at the one end,
A portion embedded in the elastic body, having a lower bending rigidity than the main cord layer, extending to the overlapping portion over the one end of the main cord layer, and overlapping the overlapping portion in the elastic body thickness direction. A reinforcing cord layer disposed within the same lug region as the one end;
Elastic crawler with. The main cord layer is configured by arranging main cords extending in the circumferential direction of the elastic body in the elastic body width direction,
The elastic crawler according to claim 1, wherein the reinforcing cord layer is configured by arranging reinforcing cords extending in an elastic body circumferential direction in an elastic body width direction. The main cord is a steel cord,
The elastic crawler according to claim 2, wherein the reinforcing cord is a steel cord made of the same material as the main cord and having a smaller diameter than the main cord.   The reinforcing cord layer is overlapped on the outer peripheral side of the elastic body of the main cord layer, and an end portion in the elastic body circumferential direction is between the one end side and the other end side forming the overlapping portion of the main cord layer. The elastic crawler of any one of Claims 1-3 currently arrange | positioned.   The reinforcing cord layer is overlaid on an outer peripheral side of the elastic body of the main cord layer, and an end portion in an elastic body circumferential direction is disposed on an outer peripheral side of the elastic body of the overlapping portion of the main cord layer. The elastic crawler of any one of 1-3.

Images