JPWO2014129659A1 - Crawler - Google Patents

Abstract

In a crawler having a main cord layer with a butt structure, the bending rigidity when wound around a drive wheel or idler wheel is made to approach uniformly in the crawler circumferential direction. The rubber crawler (10) as an example of the crawler of the present invention includes an endless belt-shaped rubber belt (12) and a main cord (32) disposed in the rubber belt (12) and extending along the crawler circumferential direction. A main cord layer (30) that is arranged in a row and has both ends in the crawler circumferential direction abutted with each other, and is disposed in the rubber belt (12) and laminated on the main cord layer (30) in the crawler circumferential direction. An auxiliary cord layer (36) formed by arranging a plurality of auxiliary cords (38) extending in the crawler width direction and extending in the crawler circumferential direction while extending along both ends (32A) of the main cord (32). And an auxiliary cord layer (42).

Description

  The present invention relates to a crawler.

  Usually, inside the rubber crawler, there is disposed a main cord layer configured by arranging main cords extending along the crawler circumferential direction in the crawler width direction. As a structure of the main cord layer, a structure in which both ends of the main cord layer in the crawler circumferential direction are abutted (hereinafter, appropriately referred to as “abutting structure”) is known. In a rubber crawler having a main cord layer with a butted structure, an auxiliary cord may be extended from one end portion of the main cord layer to the other end portion in order to ensure the tension at the butted portion (for example, Patent Document 1).

JP 2000-177660 A

  By the way, in the rubber crawler having the main cord layer having the butted structure, the bending rigidity of the overlapping portion of the main cord layer and the auxiliary cord layer is higher than the other portions. For this reason, when the overlapped portion is wound around the drive wheel or idler wheel, excessive bending (curvature) is caused by the difference in bending rigidity near the boundary between the overlapped portion and the other portion (end of the auxiliary cord layer in the crawler circumferential direction). Bending with a small radius tends to occur.

  It is an object of the present invention to make the bending rigidity of a crawler having a main cord layer having a butt structure close evenly in the crawler circumferential direction when it is wound around a driving wheel or idler wheel.

  The crawler according to the first aspect of the present invention includes an endless belt-like elastic body and a plurality of main cords arranged in the elastic body and extending along the circumferential direction of the elastic body. A main cord layer having opposite ends in the circumferential direction, and disposed in the elastic body, laminated on the main cord layer, extending along the circumferential direction of the elastic body and straddling both ends of the main cord layer; And an auxiliary cord layer configured by arranging a plurality of auxiliary cords that are extendable in the circumferential direction of the elastic body in the elastic body width direction.

  As described above, the crawler according to the present invention can make the bending rigidity close to uniform in the crawler circumferential direction when it is wound around a drive wheel or idler wheel.

The side view which looked at the rubber crawler of 1st Embodiment from the side (crawler width direction). The top view which looked at the rubber crawler shown in FIG. 1 from the crawler inner peripheral side. 3X-3X sectional drawing of the rubber crawler shown in FIG. 4X-4X sectional view of the rubber crawler shown in FIG. The enlarged view of the 5X part of the rubber crawler shown in FIG. 6X-6X sectional view of the main cord layer and each auxiliary cord layer of the rubber crawler shown in FIG. 7X-7X sectional view of the main code layer and each auxiliary code layer shown in FIG. FIG. 5 is a side cross-sectional view of the rubber crawler corresponding to a cross section taken along line 4X-4X in FIG. 2, showing a state where the overlapping portion of the rubber crawler shown in FIG. 4 is wound around the sprocket. The developed view which looked at the auxiliary | assistant cord layer which shows the state which the auxiliary | assistant cord layer of the rubber crawler of the state shown in FIG. 8 extended in the crawler circumferential direction from the crawler outer peripheral side. The expanded view which looked at the auxiliary | assistant cord layer which shows the state which the auxiliary | assistant cord layer of the rubber crawler of the state shown in FIG. 8 shrunk in the crawler circumferential direction from the crawler outer peripheral side. The expanded sectional view of the main cord shown in FIG. The expanded sectional view of the auxiliary | assistant cord shown in FIG. 2 is a sectional side view of the rubber crawler of the second embodiment cut along the circumferential direction of the crawler on the core metal wing portion, as viewed from the crawler width direction (side sectional view corresponding to the section 4X-4X in FIG. 2). . Side sectional view of a cut surface obtained by cutting the rubber crawler of the third embodiment along the crawler circumferential direction on the core metal wing portion from the crawler width direction (side sectional view corresponding to the section 4X-4X in FIG. 2) . 4 is a cross-sectional side view of the cut surface of the rubber crawler of the fourth embodiment cut along the circumferential direction of the crawler on the core wing portion (a cross-sectional side view corresponding to the cross section taken along line 4X-4X in FIG. 2). . The top view which looked at the internal peripheral surface of the rubber crawler of 5th Embodiment. The 17X-17X sectional view taken on the line of the rubber crawler shown in FIG. The 18X-18X sectional view taken on the line of the rubber crawler shown in FIG. It is an expanded sectional view of the main cord of a modification. 7 is a side sectional view of a cut surface obtained by cutting a rubber crawler according to a seventh embodiment along a crawler circumferential direction on a core metal blade portion (a side sectional view corresponding to a cross section taken along line 4X-4X in FIG. 2). . It is an expanded sectional view of an auxiliary cord used with a rubber crawler of a 7th embodiment. It is an expanded sectional view of the modification of the auxiliary cord used with the rubber crawler of a 7th embodiment.

(First embodiment)
The 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 a 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 vehicle. It is used by being wound around an idler 102, which is an example of an idler wheel that is rotatably attached to the wheel. 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 described as “crawler circumferential direction”, and the width direction of rubber crawler 10 (in the direction of arrow W in FIG. 2) is expressed as “crawler width”. "Direction". The crawler circumferential direction (synonymous with the longitudinal direction of the rubber crawler 10) and the crawler width direction are orthogonal to each other when the rubber crawler 10 is viewed from the inner peripheral side or the outer peripheral side.
Further, in the present embodiment, the inner peripheral side (the arrow IN direction side in FIGS. 3 and 4) 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”. The outer peripheral side of the rubber crawler 10 (the arrow OUT direction side in FIGS. 3 and 4) is referred to as the “crawler outer peripheral side”. 3 and 4, the arrow IN direction (annular inner direction) and arrow OUT direction (annular outer direction) are the inner and outer directions of the rubber crawler 10 in the wound state (synonymous with the thickness direction of the rubber crawler 10). Show.

  In this embodiment, the rubber crawler 10 is wound around the sprocket 100 and the idler 102, but the present invention is not limited to this configuration. For example, depending on the arrangement of the sprocket 100, the idler 102, and the roller 104, the rubber crawler 10 may be wound around one or a plurality of the rollers 104 in addition to the sprocket 100 and the idler 102.

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. Further, 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 to keep the tension (tension) of the rubber crawler 10 constant.
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. (Refer to FIG. 3 and FIG. 4).
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 belt-like 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). The cored bar 20 of this embodiment is formed of a metal material. In addition, as long as the metal core 20 has sufficient strength with respect to the specification of the rubber crawler 10, the present invention may be made of a material other than a metal material. For example, the core metal 20 may be formed of a resin 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. 12 may be exposed.

  The cored bar protrusion 26 protrudes from the rubber belt 12 to the inner peripheral side of the crawler 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 core metal protrusion 26, the structure by which rubber | gum coating is not carried out or only one part may be rubber-coated.

  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).

  In the present embodiment, as shown in FIG. 2, a straight line passing through the center in the crawler width direction of the core bar center portion 22 of the core bar 20 (hereinafter referred to as “core bar center line” as appropriate) and the rubber belt 12. A straight line passing through the center in the crawler width direction (hereinafter referred to as a center line CL) substantially coincides. In addition, this invention is not limited to the said structure, The core metal center line of the metal core 20 may have shifted | deviated to the crawler width direction with respect to the center line CL of the rubber belt 12. FIG. In the present embodiment, the side close to the center line CL along the crawler width direction is the crawler width direction inside, and the far side is the crawler width direction outside.

  As shown in FIGS. 2 and 3, on both sides of the crawler width direction across the pair of core metal protrusions 26 of the rubber belt 12, there are rolling wheel rolling surfaces 16 that protrude on the inner peripheral side of the crawler and extend along the circumferential direction of the crawler. Each is formed. The rolling wheel rolling surface 16 is flat, and the above-described rolling wheel 104 rolls.

  As shown in FIG. 2, on the inner periphery of the rubber belt 12, there is an engagement recess 50 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 formed. In addition, this invention is not limited to this structure, Instead of the engagement recessed part 50, 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 50. 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 50, a driving force is applied to the core metal central portion 22 of the core metal 20 via the engagement recess 50. The driving force is transmitted to the rubber belt 12 (rubber crawler 10).

  As shown in FIG. 1, lugs 14 and 15 that protrude toward the outer periphery of the crawler are alternately arranged on the outer periphery of the rubber belt 12 with an interval in the crawler circumferential direction. The lugs 14 and 15 are formed of a rubber material, and constitute a grounding portion that contacts the ground of the rubber crawler 10. The lugs 14 and 15 both extend along the crawler width direction. On the other hand, as shown in FIG. 3, the lug 14 is wider than the lug 15 (here, the length along the crawler width direction is longer).

  As shown in FIG. 4, the lugs 14 and 15 are respectively disposed on the crawler outer peripheral side of the cored bar 20. In other words, the cored bar 20 and the lug 14 are overlapped in the crawler inside / outside direction (crawler thickness direction). In addition, this invention is not limited to the said structure, You may use a conventionally well-known thing about the arrangement position and shape of a lug.

  As shown in FIGS. 3 and 4, a main cord layer 30 is disposed in the rubber belt 12 along the crawler circumferential direction on the crawler outer circumferential side of the pair of cored bar blade portions 24. The main cord layer 30 is configured by arranging a plurality of main cords 32 extending in the crawler circumferential direction in the crawler width direction. The main cords 32 arranged in the crawler width direction are entirely covered with a rubber material (indicated by a covering rubber 33 in FIG. 7). Specifically, the main cord layer 30 is composed of a main cord ply in which a plurality of main cords 32 are embedded in an endless rubber material. In the present embodiment, the same rubber material as the rubber belt 12 is used as the covering rubber 33, but the present invention is not limited to this configuration, and a rubber material different from the rubber belt 12 may be used as the covering rubber 33. The main code 32 of the present embodiment is an example of the main code of the present invention, and the main code layer 30 of the present embodiment is an example of the main code layer of the present invention.

The main cord layer 30 is abutted at both ends in the crawler circumferential direction. Specifically, the main cord 32 that constitutes the main cord layer 30 makes one round in the rubber belt 12, and as shown in FIGS. 4 and 5, both ends in the longitudinal direction (synonymous with both ends in the crawler circumferential direction). ) 32A is abutted. Here, both end portions 32A of the main cord 32 are butted so that no gap is formed between them even if they are abutted so that a gap is formed therebetween (in other words, both end portions 32A are in contact). Alternatively, the butted portions may be joined (for example, welded). As shown in FIGS. 4 and 5, the main cord 32 of this embodiment has both end portions 32 </ b> A abutted so that a gap is formed therebetween. In the present embodiment, both end portions 32A of each main cord 32 are butted so that the center line (the one-dot chain line in FIG. 6) coincides, but the present invention is not limited to this configuration and includes the covering rubber 33. As long as both end portions of the main cord layer 30 are abutted, the center line may be shifted between both end portions 32 </ b> A of each main cord 32. For example, both end portions 32 </ b> A of the main cord 32 may be displaced in the crawler width direction beyond the diameter of the main cord 32. In this case as well, both end portions 32A of the main cord 32 appear to face each other when viewed from the crawler width direction.
Further, each main cord 32 constituting the main cord layer 30 has a crawler outer peripheral side (the lower side in FIGS. 4 and 5) of the cored bar 20 (specifically, the cored bar blade section 24) having the same end portions 32 </ b> A. It is arranged. The present invention is not limited to this configuration, and both end portions 32 </ b> A of each main cord 32 may not be disposed on the crawler outer peripheral side of the same core metal 20.

  As shown in FIG. 11, the main cord 32 of the present embodiment is formed by twisting a plurality of strands 34. The strand 34 is formed by twisting a plurality of filaments 35 together. In addition, this invention is not limited to the said structure, You may use the main code 132 shown, for example in FIG. 19 as a main code of this invention. The main cord 132 is formed by twisting a plurality of strands 134 formed by twisting a plurality of filaments 135.

  In the present embodiment, a steel cord excellent in tensile strength (a steel cord formed by twisting a plurality of steel strands formed by twisting a plurality of steel filaments) is used as an example of the main cord 32. . In addition, this invention is not limited to the said structure, If the sufficient tensile strength and the bending rigidity as the main cord layer 30 can be ensured, the organic comprised with organic fiber (for example, nylon fiber, aromatic polyamide fiber etc.) A fiber cord may be used as the main cord.

As shown in FIGS. 3 and 4, in the rubber belt 12, an auxiliary cord layer 36 extending in the crawler circumferential direction is disposed on the crawler outer circumferential side of the main cord layer 30. The auxiliary cord layer 36 is laminated on the main cord layer 30 so as to straddle both end portions of the main cord layer 30 (both end portions 32A of each main cord 32). The auxiliary cord layer 36 is configured by arranging a plurality of auxiliary cords 38 extending in the crawler circumferential direction in the crawler width direction. The auxiliary cord 38 straddles both end portions 32A of the main cord 32 when viewed from the crawler width direction.
Further, the auxiliary cords 38 arranged in the crawler width direction are entirely covered with a rubber material (indicated by a covering rubber 39 in FIG. 7). Specifically, the auxiliary cord layer 36 is configured by an auxiliary cord ply in which a plurality of auxiliary cords 38 are embedded in an endless rubber material.
In the present embodiment, the same rubber material as the rubber belt 12 is used as the covering rubber 39, but the present invention is not limited to this configuration, and a rubber material different from the rubber belt 12 may be used as the covering rubber 39. The auxiliary cord 38 of the present embodiment is an example of the auxiliary cord of the present invention, and the auxiliary cord layer 36 of the present embodiment is an example of the auxiliary cord layer of the present invention.

  The auxiliary cord 38 can be expanded and contracted in the crawler circumferential direction. Specifically, as shown in FIG. 6, the auxiliary cord 38 has a bent portion 40 that gently bends the main cord 32 so as to have an amplitude in the crawler width direction that is a direction orthogonal to the crawler circumferential direction. ing. Specifically, in the present embodiment, the auxiliary cord 38 has a plurality of bent portions 40, and the bent portions 40 adjacent to each other in the crawler circumferential direction are bent in opposite directions when viewed from the crawler thickness direction ( In other words, the amplitude directions of the adjacent bent portions 40 are opposite to each other). In addition, the auxiliary cord 38 has bent portions 40 adjacent to each other in the crawler circumferential direction continuous with each other when viewed from the crawler thickness direction. Note that the auxiliary cord 38 of the present embodiment extends in a wave shape (for example, a sine wave shape, a rectangular wave shape, a zigzag shape, etc.) in the crawler circumferential direction as viewed from the crawler thickness direction.

  As shown in FIG. 6, when viewed from the crawler thickness direction, the bent portions 40 of the auxiliary cords 38 adjacent in the crawler width direction are bent in the same direction. Specifically, the wave shapes of the auxiliary cords 38 adjacent in the crawler width direction have the same phase and the same amplitude. The present invention is not limited to the above configuration. For example, the wave shapes of the auxiliary cords adjacent in the crawler width direction have different amplitudes but the same phase and phase are different, but the same amplitude, or both amplitude and phase are different. It may be a configuration. In FIG. 6, the amplitude of the waveform of the auxiliary cord 38 (the amplitude of the bent portion 40) is denoted by reference symbol A <b> 1, and the wavelength of the waveform of the auxiliary cord 38 (twice the distance between the end portions of the bent portion 40) Indicated by λ1. In FIG. 6, alternate long and short dash lines passing through the centers of the auxiliary cord 38 and the auxiliary cord 44 described later are the center lines of the auxiliary cord 38 and the auxiliary cord 44 described later.

  As shown in FIG. 4, both end portions 38A in the longitudinal direction of the auxiliary cord 38 (synonymous with both end portions in the crawler circumferential direction) are arranged on the crawler inner circumferential side of the lug 14 or the lug 15 as viewed from the crawler width direction. Has been. The present invention is not limited to this configuration, and at least one of the both end portions 38 </ b> A of the auxiliary cord 38 may be disposed between the lug 14 and the lug 15.

  In this embodiment, the bonding area of the main cord layer 30 and the auxiliary cord layer 36 is A, the allowable stress of the covering rubber 39 (the same rubber material as the covering rubber 33 in this embodiment) is K, and the total amount of the main cord layer 30 is When the strength (strength per main cord 32 × the number of driven main cords 32) is H, A × K ≧ H is satisfied. By satisfying this relationship, delamination between the main cord layer 30 and the auxiliary cord layer 36 can be effectively suppressed.

As shown in FIG. 12, the auxiliary cord 38 of the present embodiment is formed by twisting a plurality of filaments 47 together. In the present embodiment, a steel cord (steel cord formed by twisting a plurality of steel filaments) having excellent tensile strength is used as an example of the auxiliary cord 38. In addition, this invention is not limited to the said structure, If the sufficient tensile strength and the bending rigidity as the auxiliary | assistant cord layer 36 are securable, the organic comprised with organic fiber (for example, nylon fiber, aromatic polyamide fiber etc.) will be sufficient as it. A fiber cord may be used as an auxiliary cord.
In the present embodiment, the auxiliary cord 38 is formed by twisting a plurality of filaments 47. However, the present invention is not limited to this configuration, and the auxiliary cord 38 may be a single filament. Good.

  Further, the auxiliary cord 38 has a smaller diameter than the main cord 32. The auxiliary cord layer 36 has a thickness (thickness along the crawler thickness direction) that is thinner than the main cord layer 30 and a width (width along the crawler width direction) that is substantially the same as the main cord layer 30.

  As shown in FIGS. 3 and 4, in the rubber belt 12, an auxiliary cord layer 42 having the same configuration as the auxiliary cord layer 36 is laminated on the crawler inner peripheral side of the main cord layer 30. Specifically, the auxiliary cord layer 42 includes an auxiliary cord 44 corresponding to the auxiliary cord 38 and a covering rubber 45 corresponding to the covering rubber 39. The auxiliary cord 44 is composed of a filament 47 corresponding to the filament 41. The bent portion 46 of the auxiliary cord 44 corresponds to the bent portion 40 of the auxiliary cord 38.

  Further, in the present embodiment, when viewed from the crawler thickness direction, the waveform of the auxiliary cord 38 and the waveform of the auxiliary cord 44 have the same phase and the same amplitude. The present invention is not limited to the above-described configuration. For example, the waveform of the auxiliary cord 38 and the waveform of the auxiliary cord 44 have different amplitudes but the same phase, or are out of phase but have the same amplitude. There may be. In FIG. 6, the amplitude of the waveform of the auxiliary cord 44 (the amplitude of the bent portion 46) is indicated by a symbol A2, and the wavelength (twice the distance between the end portions of the bent portion 46) is indicated by λ2. The auxiliary cord 44 of the present embodiment is an example of the auxiliary cord of the present invention, and the auxiliary cord layer 42 of the present embodiment is an example of the auxiliary cord layer of the present invention.

  The auxiliary cord layer 42 is disposed at the same position in the crawler circumferential direction as the auxiliary cord layer 36 with the main cord layer 30 interposed therebetween. That is, both end portions 44A in the longitudinal direction of the auxiliary cord 44 (both end portions in the crawler circumferential direction) are disposed on the crawler inner peripheral side of the core metal 20 (specifically, the core metal blade portion 24).

The total strength of the auxiliary code layer 36 and the auxiliary code layer 42 is equal to or greater than the total strength of the main code layer 30.
The total strength of the main cord layer 30 is obtained by multiplying the number of driven main cords 32 by the strength (tensile force) when one main cord 32 is broken.
Similarly, the total strength of the auxiliary cord layer 36 is obtained by multiplying the number of driven auxiliary cords 38 by the strength (tensile force) when one auxiliary cord 38 is broken, and the total strength of the auxiliary cord layer 42 is It is obtained by multiplying the number of cords 44 to be driven by the strength of one auxiliary cord 44 when it is broken.

Next, the effect of the rubber crawler 10 of this embodiment is demonstrated.
In the rubber crawler 10, the rubber belt 12 is bent at a portion wound around the sprocket 100 and the idler 102 with the main cord layer 30 serving as a center plane of bending. At this time, with the main cord layer 30 as a reference, a compressive force acts on the inner peripheral side of the crawler, and a tensile force acts on the outer peripheral side of the crawler.

Here, in the rubber crawler 10, as shown in FIG. 8, a portion where the main cord layer 30, the auxiliary cord layer 36 and the auxiliary cord layer 42 are overlaid (hereinafter referred to as “overlapping portion” as appropriate) is provided. When wound around the sprocket 100 or the idler 102, the main cord layer 30 becomes the center of bending, and the auxiliary cord layer 36 and the auxiliary cord layer 42 expand and contract in the crawler circumferential direction. Specifically, as shown in FIG. 9, since a tensile force acts on the auxiliary cord layer 36, a plurality of bent portions 40 of the auxiliary cord 38 extend. That is, the length of the auxiliary cord 38 in the circumferential direction of the crawler increases (becomes longer). As a result, the length of the auxiliary cord layer 36 in the crawler circumferential direction also increases. On the other hand, as shown in FIG. 10, since the compressive force acts on the auxiliary cord layer 42, the plurality of bent portions 46 of the auxiliary cord 44 are further bent and contracted. That is, the length of the auxiliary cord 44 in the crawler circumferential direction contracts (shortens). As a result, the length of the auxiliary cord layer 42 in the crawler circumferential direction is also reduced.
For this reason, in the rubber crawler 10, the difference in bending rigidity between the overlapped portion and other portions is reduced. That is, according to the rubber crawler 10, the bending rigidity when wound around the sprocket 100 or the idler 102 can be made closer to the crawler circumferential direction.
Thereby, when the said overlapping part winds around the sprocket 100 and the idler 102, it can suppress that an excessive bending arises in the rubber belt 12 in the boundary vicinity of an overlapping part and another part. As a result, it is possible to reduce bending fatigue since excessive bending is prevented from repeatedly occurring in a part of the rubber belt 12 (near the boundary).

  In the rubber crawler 10, both end portions of the main cord layer 30 (both end portions 32 </ b> A of each main cord 32) are sandwiched between the auxiliary cord layer 36 and the auxiliary cord layer 42, so that the vicinity of the end portion of the main cord layer 30 is a starting point. Excessive bending can be suppressed.

  Further, in the rubber crawler 10, when viewed from the crawler thickness direction, the bent portion 40 of the auxiliary cord 38 is bent in the crawler width direction, that is, the amplitude direction of the bent portion 40 is set in the crawler width direction. The thickness of the cord layer 36 (thickness in the crawler thickness direction) can be reduced. Similarly, since the thickness of the auxiliary cord layer 42 (thickness in the crawler thickness direction) can be reduced, the weight can be reduced.

  Furthermore, in the rubber crawler 10, since the bent portions 40 adjacent to each other in the crawler circumferential direction of the auxiliary cord 38 are bent in opposite directions, the crawler circumferential direction input to the auxiliary cord 38 (tensile force and compressive force). ), The auxiliary cord layer 36 can be expanded and contracted in a balanced manner in the crawler circumferential direction. Similarly, the auxiliary cord layer 42 can be expanded and contracted in a balanced manner in the crawler circumferential direction with respect to the input (tensile force and compressive force) in the crawler circumferential direction to the auxiliary cord 44. Further, since the bent portions 40 adjacent to each other in the crawler circumferential direction of the auxiliary cord 38 are made continuous when viewed from the crawler thickness direction, the amount of expansion / contraction of the auxiliary cord 38 in the crawler circumferential direction can be increased. Similarly, the extension / contraction amount of the auxiliary cord 44 in the crawler circumferential direction can be increased.

In the rubber crawler 10, when viewed from the crawler thickness direction, the bent portions 40 of the auxiliary cords 38 adjacent in the crawler width direction are bent in the same direction, that is, the amplitude of the bent portion 40 of the adjacent auxiliary cord 38. Since the directions are the same as each other, the amount of expansion and contraction of each auxiliary cord 38 in the crawler circumferential direction can be made closer to each other. Similarly, the amount of expansion / contraction of each auxiliary cord 44 in the crawler circumferential direction can be made close to uniform. In particular, in the rubber crawler 10, since the wave shapes of the auxiliary cords 38 adjacent in the crawler width direction have the same phase and the same amplitude, the amount of expansion / contraction of each auxiliary cord 38 in the crawler circumferential direction (in this embodiment, the amount of elongation) ) Can be made uniform. As a result, the expansion / contraction amount of the auxiliary cord layer 36 in the crawler circumferential direction (in this embodiment, the expansion amount) can be made close to constant in the crawler width direction.
Similarly, since the auxiliary cords 44 adjacent in the crawler width direction have the same phase and the same amplitude, the expansion / contraction amount (contraction amount in the present embodiment) of each auxiliary cord 44 in the crawler circumferential direction is made close to uniform. Can do. Thereby, the amount of expansion / contraction of the auxiliary cord layer 42 in the crawler circumferential direction (in this embodiment, the amount of contraction) can be made almost constant in the crawler width direction.

  In the rubber crawler 10, the total strength of the auxiliary cord layer 36 and the auxiliary cord layer 42 is greater than or equal to the total strength of the main cord layer 30, so that even in the gap portion between the both end portions 32 </ b> A of the main cord 32. Sufficient tension is secured by the auxiliary cord layer 36 and the auxiliary cord layer 42. That is, in the rubber crawler 10, the auxiliary cord layer 36 and the auxiliary cord layer 42 can sufficiently secure the tension during traveling.

On the other hand, in the rubber crawler 10, when the overlapping portion is wound around the sprocket 100 or the idler 102, the auxiliary cord layer 36 extends in the crawler circumferential direction. The compressive force acting on the part corresponding to the 30 overlapping portions can be reduced. Further, since the auxiliary cord layer 36 extends in the crawler circumferential direction as described above, the shearing force acting on the rubber between the main cord layer 30 and the auxiliary cord layer 36 can be reduced. Thereby, peeling (interlayer peeling) between the main cord layer 30 and the auxiliary cord layer 36 can be suppressed.
Further, the rubber crawler 10 has an auxiliary cord layer 42 that contracts in the crawler circumferential direction when the overlapping portion is wound, so that, for example, the rubber crawler 10 has an overlapping portion of the main cord layer 30 as compared with the auxiliary cord layer 42 that does not contract. The compressive force (compressive stress) acting on the corresponding part can be reduced. Further, since the auxiliary cord layer 42 extends in the crawler circumferential direction as described above, the shearing force acting on the rubber between the main cord layer 30 and the auxiliary cord layer 42 can be reduced. Thereby, peeling (interlayer peeling) between the main cord layer 30 and the auxiliary cord layer 42 can be suppressed.

In the first embodiment, the auxiliary code layer 36 and the auxiliary code layer 42 have the same configuration, but the present invention is not limited to this configuration, and the auxiliary code layer 36 and the auxiliary code layer 42 may have different configurations. For example, the lengths of the auxiliary cord layer 36 and the auxiliary cord layer 42 may be different, the amplitudes and phases of the auxiliary cord 38 and the auxiliary cord 44 may be different, and the materials of the auxiliary cord 38 and the auxiliary cord 44 may be different. The cord diameter and the twisted structure of the cord may be different.
In addition, since a tensile force acts on the auxiliary cord layer 36 and a compressive force acts on the auxiliary cord layer 42, it is preferable that the configurations of the auxiliary cord layer 36 and the auxiliary cord layer 42 are made different depending on the acting force. .

  In the first embodiment, the auxiliary cord 38 has a bent portion 40 that is bent so as to have an amplitude in the crawler width direction when viewed from the crawler thickness direction. The cord 38 may have a bent portion that is bent so as to have an amplitude in the crawler thickness direction when viewed from a direction orthogonal to the crawler circumferential direction, for example, the crawler width direction. Further, if the auxiliary cord 38 has an amplitude in a direction orthogonal to the crawler circumferential direction, for example, a portion connecting the bent portions 40 adjacent to each other in the crawler circumferential direction is linear along the crawler circumferential direction. It may be configured to extend. On the other hand, the auxiliary cord 38 may be arranged along the crawler circumferential direction while being spirally wound around the crawler circumferential direction as a central axis. The configuration of the auxiliary cord 38 may be applied to the auxiliary cord 44 and all the auxiliary cords of the second to fifth embodiments described later.

(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 FIG. 13, in the rubber crawler 60 of the present embodiment, an auxiliary cord layer 62 is laminated on the crawler outer peripheral side of the auxiliary cord layer 36, and an auxiliary cord layer 66 is laminated on the crawler inner peripheral side of the auxiliary cord layer 42. The configuration is the same as that of the rubber crawler 10 of the first embodiment except for the configuration described above. Therefore, the auxiliary code layer 62 and the auxiliary code layer 66 will be described below.
The auxiliary cords 64 and 68 of the present embodiment are examples of the auxiliary cord of the present invention, and the auxiliary code layers 62 and 66 of the present embodiment are examples of the auxiliary code layer of the present invention.

As shown in FIG. 13, the auxiliary cord layer 62 has the same configuration as the auxiliary cord layer 36 except for the length in the crawler circumferential direction. Specifically, the auxiliary cord layer 62 includes an auxiliary cord 64 corresponding to the auxiliary cord 38 and a covering rubber (not shown) corresponding to the covering rubber 39.
Further, the auxiliary cord layer 62 straddles both ends of the main cord layer 30 (both ends 32A of each main cord 32) from the crawler outer peripheral side when viewed from the crawler width direction.
In the present embodiment, the waveform of the auxiliary cord 64 and the waveform of the auxiliary cord 38 have the same phase and the same amplitude. The present invention is not limited to the above-described configuration. For example, the waveform of the auxiliary cord 64 and the waveform of the auxiliary cord 38 have different amplitudes but have the same phase and phase, but have the same amplitude or amplitude. May have different configurations.

Further, the auxiliary cord layer 62 far from the main cord layer 30 has a shorter length in the crawler circumferential direction than the auxiliary cord layer 36 close to the main cord layer 30.
Furthermore, in the auxiliary cord layer 36 and the auxiliary cord layer 62, the end portion 38A of each auxiliary cord 38 and the end portion 64A of the auxiliary cord 64 are shifted in the crawler circumferential direction.

On the other hand, the auxiliary cord layer 66 has the same configuration as the auxiliary cord layer 42 except for the length in the crawler circumferential direction. Specifically, the auxiliary cord layer 66 includes an auxiliary cord 68 corresponding to the auxiliary cord 44 and a covering rubber (not shown) corresponding to the covering rubber 45.
Further, the auxiliary cord layer 66 straddles both end portions 32A of the main cord 32 from the crawler inner peripheral side when viewed from the crawler width direction.

  In the present embodiment, the auxiliary code 68 and the auxiliary code 44 have the same phase and the same amplitude. The present invention is not limited to the above-described configuration. For example, the auxiliary cord 44 and the auxiliary cord 68 have different amplitudes but have the same phase and phase but have the same amplitude, or have different amplitude and phase. Also good.

The auxiliary cord layer 66 far from the main cord layer 30 is shorter in the crawler circumferential direction than the auxiliary cord layer 42 close to the main cord layer 30.
Furthermore, in the auxiliary cord layer 42 and the auxiliary cord layer 66, the end portion 44A of each auxiliary cord 44 and the end portion 68A of the auxiliary cord 68 are shifted in the crawler circumferential direction.

In the present embodiment, the length of the auxiliary cord layer 62 and the auxiliary cord layer 66 along the crawler circumferential direction and the width along the crawler width direction are the same. The auxiliary cord layer 62 and the auxiliary cord layer 66 are disposed at the same position in the crawler circumferential direction with the main cord layer 30 interposed therebetween.
Further, the total strength of the auxiliary code layer 36, the auxiliary code layer 42, the auxiliary code layer 62, and the auxiliary code layer 66 is equal to or greater than the total strength of the main code layer 30.

Further, since the auxiliary cord layer 62 is arranged on the outer periphery side of the crawler than the auxiliary cord layer 36, the tensile force acting at the time of winding becomes larger than that of the auxiliary cord layer 36. For this reason, it is preferable to make the auxiliary cord layer 62 have an allowance for extending the auxiliary cord layer 36 or more. As an example, the wavelength of the auxiliary cord 64 may be shorter than the wavelength of the auxiliary cord 38 while making the amplitudes of the auxiliary cord 64 and the auxiliary cord 38 the same. Note that the present invention is not limited to this configuration, and the wavelength and amplitude of the auxiliary cord 64 may be the same as that of the auxiliary cord 38 or may be other than that.
Further, since the auxiliary cord layer 66 is disposed on the inner peripheral side of the crawler with respect to the auxiliary cord layer 42, the compressive force acting at the time of winding becomes larger than that of the auxiliary cord layer 42. For this reason, it is preferable that the auxiliary cord layer 66 has a contraction margin greater than that of the auxiliary cord layer 42. As an example, the wavelength of the auxiliary cord 68 may be made longer than the wavelength of the auxiliary cord 44 while making the amplitudes of the auxiliary cord 68 and the auxiliary cord 44 the same. The present invention is not limited to this configuration, and the wavelength and amplitude of the auxiliary cord 68 may be the same as those of the auxiliary cord 44 or may be other than that.

Next, the effect of the rubber crawler 60 of this embodiment is demonstrated. Note that, among the operational effects of the present embodiment, the description of the operational effects similar to those of the first embodiment will be omitted as appropriate.
In the rubber crawler 60, two layers of the auxiliary cord layer 36 and the auxiliary cord layer 62 are laminated on the crawler outer peripheral side of the main cord layer 30, and two layers of the auxiliary cord layer 42 and the auxiliary cord layer 66 are laminated on the inner peripheral side of the crawler. By adjusting the expansion / contraction amount (wavelength or amplitude) of each auxiliary cord layer, the bending rigidity of the overlapping portion of the main cord layer 30 and each auxiliary cord layer can be optimized.

  In the rubber crawler 60, since the end portion 38A of the auxiliary cord layer 36 and the end portion 64A of the auxiliary cord layer 62 are shifted in the crawler circumferential direction, the overlapping portion of the main cord layer 30 and the auxiliary cord layers 36 and 62, and others The difference in bending rigidity of the portion can be reduced. On the other hand, since the end portion 44A of the auxiliary cord layer 42 and the end portion 68A of the auxiliary cord layer 66 are shifted in the crawler circumferential direction, the overlapping portion of the main cord layer 30 and the auxiliary cord layers 42 and 66 and other portions are arranged. The difference in bending rigidity can be reduced.

  In the rubber crawler 60, the length of the auxiliary cord layers 62 and 66 far from the main cord layer 30 along the elastic body circumferential direction is shorter than the auxiliary cord layers 36 and 42 close to the main cord layer 30, so It is possible to reduce the weight while ensuring the bending rigidity.

  In the second embodiment, the two auxiliary cord layers 36 and 62 are laminated on the crawler outer peripheral side of the main cord layer 30, and the two auxiliary cord layers 42 and 66 are laminated on the crawler inner peripheral side. The present invention is not limited to this configuration, and three or more auxiliary cord layers may be provided on the crawler outer peripheral side of the main cord layer 30, and three or more auxiliary cord layers may be provided on the crawler inner peripheral side of the main cord layer 30. It may be provided.

(Third embodiment)
Next, a rubber crawler according to a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 2nd Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 14, in the rubber crawler 70 of the present embodiment, the auxiliary cord layer 36 and the auxiliary cord layer 62 are laminated on the crawler outer peripheral side of the main cord layer 30, but the auxiliary cord layer 42 and the auxiliary cord layer 42 on the inner peripheral side of the crawler. Except for the configuration in which the auxiliary cord layer 66 is not stacked, the configuration is the same as the rubber crawler 60 of the second embodiment.

Next, the effect of the rubber crawler 70 of this embodiment is demonstrated. Of the operational effects of the present embodiment, descriptions of the operational effects similar to those of the second embodiment are omitted as appropriate.
In the rubber crawler 70 of the present embodiment, the auxiliary cord layer 42 and the auxiliary cord layer 66 are not stacked on the crawler inner peripheral side of the main cord layer 30 unlike the rubber crawler 60 of the second embodiment, so that the weight can be reduced. it can. Further, since the rubber crawler 70 can reduce the thickness of the rubber belt 12 as compared with the rubber crawler 60, it can suppress the tensile strain generated on the outer periphery of the rubber belt 12 when it is wound around the sprocket 100 or the idler 102.
Further, as shown in FIG. 14, both end portions of the main cord layer 30 (both end portions 32A of the main cords 32) are arranged on the crawler outer peripheral side of the same core metal 20, so that they are wound around the sprocket 100 and the idler 102. Since the movement is constrained when applied, it is possible to suppress excessive bending from occurring in the vicinity of both end portions 32A.

(Fourth embodiment)
Next, a rubber crawler according to a fourth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 2nd Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 15, in the rubber crawler 72 of this embodiment, the auxiliary cord layer 36 and the auxiliary cord layer 62 are laminated on the crawler outer peripheral side of the main cord layer 30, but the auxiliary cord layer 42 is laminated on the crawler inner peripheral side. The configuration is the same as that of the rubber crawler 60 of the second embodiment except that only the auxiliary cord layer 66 is stacked without being stacked.

Next, the effect of the rubber crawler 72 of this embodiment is demonstrated. Of the operational effects of the present embodiment, descriptions of the operational effects similar to those of the second embodiment are omitted as appropriate.
In the rubber crawler 72 of this embodiment, since the auxiliary cord layer 42 is not laminated on the crawler inner peripheral side of the main cord layer 30 unlike the rubber crawler 60 of the second embodiment, the weight can be reduced. On the other hand, in the rubber crawler 72, as shown in FIG. 15, the auxiliary cord layer 66 is laminated on the crawler inner peripheral side of the main cord layer 30. It is possible to suppress excessive bending from occurring as a starting point. Further, by laminating the auxiliary cord layer 66 on the crawler inner peripheral side of the main cord layer 30, it acts on the overlapping portion of the main cord layer 30 with the auxiliary cord layer 66 as compared with the rubber crawler of the third embodiment. The compressive force can be effectively reduced.

(Fifth embodiment)
Next, a rubber crawler according to a fifth 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. 16 to 18, the rubber crawler 80 of this embodiment is not a rubber crawler for an airframe having the sprocket 100 and the idler 102 as in the first embodiment, but a pair of left and right disk-shaped drive wheels 110. And a rubber crawler for an airframe having an idler wheel (not shown). Further, the rubber crawler 80 of the present embodiment is a so-called core metal-less rubber crawler in which the core metal 20 and the engagement recess 50 are not provided as in the rubber crawler 10 of the first embodiment, but a rubber protrusion 84 is provided instead. is there.

  As shown in FIG. 16, the rubber crawler 80 of this embodiment has an endless belt-like rubber belt 82. The rubber belt 82 is formed with rubber protrusions 84 that protrude toward the inner peripheral side of the crawler with an interval in the circumferential direction of the crawler (a constant interval in the present embodiment). The rubber protrusions 84 are in contact with a drive wheel 110 and an idler wheel (not shown) that roll on the inner peripheral surface of the rubber belt 82 on both sides in the crawler width direction, and move relative to the rubber crawler 80, the drive wheel 110, and the idler wheel. It suppresses. Further, in the rubber crawler 80 of the present embodiment, the frictional force between the drive wheel 110 and the inner peripheral surface of the rubber belt, and the plurality of pin portions 111 bridged between the outer peripheral edge portions of the pair of drive wheels 110 are formed on the rubber protrusions 84. The drive force transmitted in contact is circulated between the drive wheel 110 and the idler wheel.

  As shown in FIGS. 17 and 18, a main cord layer 86 extending along the crawler circumferential direction is disposed in the rubber belt 82. The main cord layer 86 is configured by arranging main cords 88 corresponding to the main cord 32 of the first embodiment in the crawler width direction. Further, the end portion of the main cord layer 86 in the crawler width direction is located closer to the end portion side of the rubber belt 82 in the crawler width direction than the portion where the drive wheel and idler wheel of the rubber belt 82 contact each other.

  Further, an auxiliary cord layer 90 is disposed on the outer periphery side of the main cord layer 86 on the crawler. The auxiliary cord layer 90 is configured by arranging auxiliary cords 92 corresponding to the auxiliary cords 38 of the first embodiment in the crawler width direction. The auxiliary cord 92 straddles both end portions 88A of the main cord 88. Further, both ends of the auxiliary cord 92 are disposed on the crawler inner peripheral side of the lug 14 or the lug 15.

  On the other hand, an auxiliary cord layer 94 is disposed on the inner circumference side of the main cord layer 86. The auxiliary cord layer 94 is configured by arranging auxiliary cords 96 corresponding to the auxiliary cords 44 of the first embodiment in the crawler width direction. The auxiliary cord 96 straddles both end portions 88A of the main cord 88. Further, both ends of the auxiliary cord 96 are disposed on the crawler outer peripheral side of the rubber protrusion 84.

Next, the effect of the rubber crawler 80 of this embodiment is demonstrated. Note that, among the operational effects of the present embodiment, the description of the operational effects similar to those of the first embodiment will be omitted as appropriate.
In the rubber crawler 80 of the present embodiment, both end portions 92A of the auxiliary cord 92 are disposed on the crawler inner peripheral side of the lug 14 or lug 15 having a large rubber thickness. As compared with the case where the auxiliary cord 92 is disposed between the auxiliary cord 92 and the auxiliary cord 92, the excessive bending with the end portion 92A as a base point can be suppressed.
On the other hand, in the rubber crawler 80, since both end portions 96A of the auxiliary cord 96 are disposed on the crawler inner peripheral side of the rubber protrusion 84 having a large rubber thickness, for example, it is disposed between the rubber protrusions 84 having a small rubber thickness. Compared to the case, excessive bending with the end portion 96A of the auxiliary cord 96 as a base point can be suppressed. Accordingly, the durability of the rubber crawler 80 without a cored bar is improved.

  In the rubber crawler according to the first embodiment, the auxiliary cords 38 and 44 can be expanded and contracted in the crawler circumferential direction by forming the bent portions 40 and 46 in the auxiliary cords 38 and 44, respectively. However, the configuration is not limited to the above, as long as the auxiliary cord can be expanded and contracted in the crawler circumferential direction. As an example, in the rubber crawler according to the sixth embodiment, a high elongation cord is used as an auxiliary cord, and the auxiliary cord extends in the crawler circumferential direction. The “high elongation cord” is generally a cord formed by loosely twisting a plurality of strands and forming the strands so as to move with each other, and has a high extensibility (ie, a large elongation to break). The S-S curve (Stress (Strain) -Strain) has a small slope in the low strain region (low elastic modulus) and a large slope in the high strain region (high elastic modulus). By using a high elongation cord as an auxiliary cord, a process for attaching a meandering hook to the auxiliary cord is not required, so that the manufacturing process can be simplified. The configuration using the high elongation code as the auxiliary code may be applied to the second to fifth embodiments.

(Seventh embodiment)
Next, a rubber crawler according to a seventh 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 FIG. 20, the rubber crawler 140 according to the present embodiment does not have the auxiliary cord layer 36 laminated on the crawler outer peripheral side of the main cord layer 30 and corresponds to the auxiliary cord layer 42 on the crawler inner peripheral side of the main cord layer 30. The configuration is the same as that of the rubber crawler 10 of the first embodiment except for the configuration in which the auxiliary cord layer 142 is stacked.

  The auxiliary cord layer 142 is configured by arranging a plurality of auxiliary cords 144 extending linearly in the crawler circumferential direction in the crawler width direction. The auxiliary cord 144 straddles both end portions 32A of the main cord 32 when viewed from the crawler width direction. The auxiliary cord layer 142 has the same configuration as the auxiliary cord layer 42 of the first embodiment except for the configuration of the auxiliary cord 144. The auxiliary cord 144 of the present embodiment is an example of the auxiliary cord of the present invention, and the auxiliary cord layer 142 of the present embodiment is an example of the auxiliary code layer of the present invention. Further, reference numeral 144 </ b> A in FIG. 20 denotes an end portion of the auxiliary cord 144.

  As shown in FIG. 21, the auxiliary cord 144 is a strand having a layer twist structure in which a plurality of filaments 148 (5 in this embodiment) are twisted around one filament 147 located in the center. This is a double twisted structure in which a plurality of 146 (four in this embodiment) are twisted together. In addition, this invention is not limited to the said structure. For example, the strand 146 may have a single twist structure.

  In addition, the auxiliary cord 144 has the same twisting direction as that of all the layers constituting the strand 146 (here, the layer constituted by the filament 148) and the twisting direction of the strand 146 (so-called Lang twisted structure). . In addition, the twist direction of the layer comprised by the filament 148 refers to the twist direction of the filament 148. Further, when the strand 146 is a single twist, the twist direction of all the layers constituting the strand 146 is the twist direction of each filament constituting the strand 146.

  Since the auxiliary cord 144 has the twisted structure, it has a spring-like characteristic and can be expanded and contracted in the crawler circumferential direction. Specifically, when viewed from the direction orthogonal to the axial direction of the auxiliary cord 144, the auxiliary cord 144 is pulled in the axial direction of the auxiliary cord 144 in the tension-applied state, so that the auxiliary cord 144 is extended with respect to the axial direction of the auxiliary cord 144. The inclination angle (angle on the acute angle side) is smaller than that in the no-load state, and the entire auxiliary cord 144 is extended. In addition, since the auxiliary cord 144 has the above-described twisted structure, for example, than the auxiliary cord of the normal twisted structure in which the twisting direction of all the layers constituting the strand 146 and the twisting direction of the strands 146 are reversed. The amount of expansion and contraction in the crawler circumferential direction can be increased, that is, the crawler circumferential direction is excellent in stretchability.

In addition, the inclination angle of the auxiliary cord 144 with respect to the axial direction of the auxiliary cord 144 is set so that the elongation when the tension of 50% of the strength at break is applied is 1.5% or more and 15% or less. Has been.
Here, when the elongation at the time of applying a tension of 50% of the strength at break is 1.5% or more, in the rubber crawler 140, an overlapping portion in which the main cord layer 30 and the auxiliary cord layer 142 are overlapped, Since the difference in bending rigidity between the other portions becomes small, the bending rigidity when wound around the sprocket 100 or the idler 102 can be made closer to the crawler in the circumferential direction. On the other hand, when the elongation at the time of applying 50% of the tensile strength at break exceeds 15%, as the distance between the end portions of the main cord layer 30 increases, the core bars 20 positioned in the vicinity between the end portions The distance between them also increases, and there is a concern about sprocket 100 tooth skipping, sprocket 100 wear, noise, vibration, and the like.
Therefore, the auxiliary cord 144 preferably has an elongation of 1.5% or more and 15% or less when a tension of 50% of the strength at break is applied.

  The material of the auxiliary cord 144 may be the same as that of the auxiliary cord 44. In the present embodiment, the auxiliary cord 144 is a steel cord.

Next, the effect of the rubber crawler 140 of this embodiment is demonstrated. Note that, among the operational effects of the present embodiment, the description of the operational effects similar to those of the first embodiment will be omitted as appropriate.
In the rubber crawler 140, the auxiliary cord 144 can be expanded and contracted in the crawler circumferential direction by adopting a twisted structure in which the twist direction of all the layers constituting the strand 146 and the twist direction of the strands 146 are the same direction. Unlike the auxiliary cords of the first to fifth embodiments, it is not necessary to attach a meandering rod, and the manufacturing process can be simplified.

  In addition, the auxiliary cord layer 142 has a small amount of expansion and contraction with respect to compression and high durability, compared with the auxiliary cords provided with the meandering ridge like the auxiliary cords of the first to fifth embodiments. Therefore, in the rubber crawler 140, when the auxiliary cord layer 142 is laminated on the outer side of the crawler, stress in the compression direction is generated on the main cord, but the auxiliary cord layer 142 is laminated on the inner circumference side of the crawler of the main cord layer 30. As a result, the generation of stress in the compression direction on the main cord can be suppressed, and the bending rigidity when wound around the sprocket 100 or idler 102 is made more uniform in the crawler circumferential direction while reducing the load on the main cord. Can do.

  In the present embodiment, the twist structure of the auxiliary cord layer 142 is the twist structure shown in FIG. 21, but the present invention is not limited to this structure. For example, the auxiliary cord 154 shown in FIG. 22 may have a twisted structure. The auxiliary cord 154 is a modification of the auxiliary cord 144 of the seventh embodiment, and is an example of the present invention. As shown in FIG. 22, the strands 156 used for the auxiliary cord 154 have a plurality of strands (in this embodiment) around a plurality of twisted filaments (three in this embodiment) located in the center. Nine other filaments 158 are twisted to form a layer of filaments 158, and a plurality of (in this embodiment, 13) other filaments 159 are twisted around the layer to form a layer of filaments 158 Is formed. The auxiliary cord 154 has a double twisted structure in which a plurality of (six in this embodiment) other strands 156 are twisted around a single strand 156 (so-called core strand) located in the center, The twist direction of all the layers constituting the strand 156 located in the section is the same as the twist direction of the other strands 156 (so-called Lang twist). The auxiliary cord 154 having the above configuration can be expanded and contracted similarly to the auxiliary cord 144 of the seventh embodiment.

  In addition, you may apply to the 2nd-5th embodiment about the structure of the auxiliary | assistant cord 144 which expands / contracts of 7th Embodiment. That is, a meandering ridge may be provided to an auxiliary cord having a stretchable twist structure. In addition, an auxiliary cord layer having an auxiliary cord having a stretchable twisted structure and an auxiliary cord layer having an auxiliary cord provided with meandering wrinkles may be combined and applied to a rubber crawler.

  In the first to sixth embodiments, the auxiliary cord layer is configured to be disposed on a part of the rubber belt 12, but the present invention is not limited to this configuration, and the auxiliary cord layer goes around the rubber belt 12, It is good also as a structure where both ends are overlapped.

  In the first to sixth embodiments, the rubber belt 12 or the rubber belt 82 in which a rubber material is formed in an endless belt shape is used as an example of the endless belt-like elastic body of the present invention, but the present invention is not limited to this configuration. A rubber elastic belt in which an elastic body having rubber elasticity (so-called rubber elastic body) is formed in an endless belt shape, for example, a resin belt in which a resin material having rubber elasticity (for example, elastomer) is formed in an endless belt shape 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 1)
In order to confirm the effect of the present invention, the rubber crawler of the example included in the present invention and the rubber crawler of the comparative example not included in the present invention were tested as follows.

<Test rubber crawler>
Example 1: A rubber crawler having the same structure as the rubber crawler of the first embodiment.
Example 2: A rubber crawler having the same structure as the rubber crawler of the third embodiment.
Example 3: A rubber crawler having the same structure as the rubber crawler of the second embodiment.
Example 4: A rubber crawler having the same structure as the rubber crawler of the fourth embodiment.
Comparative Example 1: A rubber crawler having a structure in which both ends of the main cord layer are overlapped.
Comparative Example 2: A rubber crawler having a structure different from that of Comparative Example 1 in the twist structure of the main cord.
Details of each rubber crawler are shown in Table 1.
Further, Comparative Example 1, Example 1, and Example 2 are rubber crawlers of the same size, and Comparative Example 2, Example 3, and Example 4 are crawlers of the same size.

<Test method>
First, a disc-like body (for test purposes) having a diameter of 352 mm was formed on the overlapping portion of the main cord of the rubber crawler of Comparative Example 1 and the overlapping portion of the main cord layer and the auxiliary cord layer of the rubber crawler of Examples 1 and 2. Wheel) is pressed from the inner peripheral side of the crawler with a force of 20 kN, and each test rubber crawler is bent along the outer periphery of the test wheel. Then, the compressive force acting on the main cord under this bending state was determined by FEM analysis. As the measurement conditions, the extension of the outermost auxiliary cord layer was set to 1.7%.
On the other hand, a disc-shaped body (for testing purposes) having a diameter of 611 mm was formed on the overlapping portion of the main cord of the rubber crawler of Comparative Example 2 and the overlapping portion of the main cord layer and the auxiliary cord layer of the rubber crawlers of Examples 3 and 4. Wheel) is pressed from the inner peripheral side of the crawler with a force of 30 kN, and each test rubber crawler is bent along the outer periphery of the test wheel. Then, the compressive force acting on the main cord under this bending state was determined by FEM analysis. As the measurement conditions, the extension of the outermost auxiliary cord layer was set to 1.7%.
The results are shown in Table 1. The smaller the compressive force acting on the main cord, the better the result.

  As can be seen from Table 1, in comparison with the rubber crawlers of Comparative Examples 1 and 2, the rubber crawlers of Examples 1 to 4 have reduced compressive force (compressive stress) acting on the main cord when wound around the wheel. Yes. For this reason, if the auxiliary | assistant code layer of Examples 1-4 of this invention is laminated | stacked on the crawler which has the main code layer of butt | matching structure, durability of a main code layer, ie, the durability of a crawler, can be improved.

(Test Example 2)
Moreover, in order to confirm the effect of this invention, the rubber crawler of the Example contained in this invention and the rubber crawler of the comparative example not contained in this invention were tested as follows.

<Test rubber crawler>
Example 5: The structure is the same as that of the rubber crawler of the first embodiment, and the auxiliary cord of the auxiliary cord layer on the crawler inner peripheral side and the auxiliary cord of the auxiliary cord layer on the crawler outer peripheral side are each S-twisted (so-called rung) Rubber crawler (S twist).
Example 6: A structure (so-called Lang S twist) in which each auxiliary cord layer on the crawler outer peripheral side of the rubber crawler of the second embodiment is deleted and the auxiliary cord of each auxiliary cord layer on the crawler inner peripheral side is respectively S-twisted. Rubber crawler.
Example 7: A rubber crawler having the same structure as that of the rubber crawler of the seventh embodiment, but having a structure in which the auxiliary cords of the auxiliary cord layer are respectively Z-twisted (so-called Lang Z twist).
Comparative Example 3: A rubber crawler having a structure in which both ends of the main cord layer are overlapped.
Comparative Example 4: A rubber crawler having a structure different from that of Comparative Example 3 in the twist structure and twist direction of the main cord.
Details of each rubber crawler are shown in Table 2.
Comparative Example 3, Example 5 and Example 6 are rubber crawlers of the same size, and Comparative Example 4 and Example 7 are crawlers of the same size.

<Test method>
First, each test rubber crawler of Comparative Example 3, Example 5 and Example 6 was wound around a test sprocket and an idler having a diameter of 352 mm and rotated with a tension of 0.5 t applied. These test rubber crawlers were rotated to be bent 300,000 times, with one time being wound around a test sprocket or idler and bending. And after bending 300,000 times, around the overlapping part of the main cord of the rubber crawler of Comparative Example 3, and around the overlapping part of the main cord layer and the auxiliary cord layer of each rubber crawler of Example 5 and Example 6 It was visually confirmed whether or not there were cracks. The durability of the joint portion was evaluated as “B” when a crack occurred, and the durability of the joint portion as “A” when no crack occurred, and the results are shown in Table 2.
On the other hand, each test rubber crawler of Comparative Example 4 and Example 7 was wound around a test sprocket having a diameter of 611 mm and an idler and rotated with a tension of 0.5 t applied. These test rubber crawlers were rotated to be bent 300,000 times, with one time being wound around a test sprocket or idler and bending. And after bending 300,000 times, cracks have occurred around the overlapping portion of the main cord of the rubber crawler of Comparative Example 4 and the overlapping portion of the main cord layer and the auxiliary cord layer of the rubber crawler of Example 7. It was confirmed visually. The durability of the joint portion was evaluated as “B” when a crack occurred, and the durability of the joint portion as “A” when no crack occurred, and the results are shown in Table 2.

  As can be seen from Table 2, the rubber crawlers of Examples 5 to 7 are superior in durability of the joint portion as compared with the rubber crawlers of Comparative Examples 3 and 4. This seems to be because the compressive force (compressive stress) acting on the main cord when it is wound on the test sprocket or idler is reduced. That is, if the auxiliary cord layers of Examples 5 to 7 of the present invention are laminated on a crawler having a main cord layer having a butt structure, the durability of the main cord layer, that is, the durability of the crawler can be improved.

  The entire disclosure of Japanese Patent Application No. 2013-034965 filed on February 25, 2013 is incorporated herein by reference.

  10, 60, 70, 72, 80, 140 ... rubber crawler (crawler), 12, 82 ... rubber belt (endless elastic body), 30, 86 ... main cord layer, 32, 88 ... Main code, 32A, 88A ... end, 36, 42, 62, 66, 90, 94, 142 ... auxiliary code layer, 38, 44, 64, 68, 92, 96, 144, 154 ... Auxiliary cords 40, 46 ... bent portions, 146, 156 ... strands A1, A2 ... amplitude, S ... crawler circumferential direction (elastic body circumferential direction), W ... crawler width direction ( Elastic body width direction), IN ... crawler inner circumference side (elastic body circumference side), OUT ... crawler outer circumference side (elastic body outer circumference side).

Claims (14)

An endless belt-like elastic body,
A main cord layer that is arranged in the elastic body and is arranged by arranging a plurality of main cords extending along the circumferential direction of the elastic body in the elastic body width direction;
The auxiliary cord disposed in the elastic body and laminated on the main cord layer, extending along the circumferential direction of the elastic body, straddling both ends of the main cord layer and elastically extending in the circumferential direction of the elastic body Auxiliary cord layers that are arranged side by side in the body width direction,
Crawler with.   2. The crawler according to claim 1, wherein the auxiliary cord has an elongation of not less than 1.5% and not more than 15% when a tension of 50% of the strength at break is applied.   The auxiliary cord is a double twist structure in which a plurality of strands of a single twist structure or a layer twist structure are twisted together, and the twist direction of all the layers constituting the strand and the twist direction of the strands are the same direction. The crawler according to claim 1 or claim 2.   The auxiliary cord has a double twist structure in which a plurality of other strands are twisted around the strand located in the center, and the twist direction of all the layers constituting the strand located in the center and the other The crawler according to claim 3, wherein a twist direction of the strand is the same direction.   The crawler according to any one of claims 1 to 4, wherein the auxiliary cord has a bent portion bent so as to have an amplitude in a direction orthogonal to the circumferential direction of the elastic body.   The crawler according to claim 5, wherein the bent portion is bent in the elastic body width direction when viewed from the elastic body thickness direction. The auxiliary cord has a plurality of the bent portions,
The crawler according to claim 6, wherein the bent portions adjacent to each other in the circumferential direction of the elastic body are bent in opposite directions as viewed from the thickness direction of the elastic body.   The crawler according to claim 6 or 7, wherein the bent portions of the auxiliary cords adjacent to each other in the elastic body width direction are bent in the same direction as viewed from the elastic body thickness direction.   The crawler according to claim 8, wherein the bent portions adjacent to each other in the circumferential direction of the elastic body are continuous when viewed from the elastic body thickness direction.   The crawler according to any one of claims 1 to 9, wherein the auxiliary cord layer is laminated on an elastic body outer circumferential side and an elastic body outer circumferential side of the main cord layer, respectively.   The crawler according to claim 10, wherein the sum of the total strengths of the plurality of auxiliary code layers is equal to or greater than the total strength of the main code layers.   The crawler according to any one of claims 1 to 11, wherein a plurality of the auxiliary cord layers are laminated on at least one side of an elastic body outer peripheral side and an elastic body outer peripheral side of the main cord layer.   The crawler according to claim 12, wherein each of the auxiliary cord layers overlapping each other has an end portion in the circumferential direction of the elastic body displaced in the circumferential direction of the elastic body.   The auxiliary cord layer far from the main cord layer among the auxiliary cord layers overlapping each other has a shorter length along the elastic body circumferential direction than the auxiliary cord layer close to the main cord layer. Crawler.

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