JP2011046359A - Coreless rubber crawler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber crawler that effectively suppresses the occurrence of cracks in a part of a rubber elastic body corresponding to the side edge of a reinforcing ply. <P>SOLUTION: A coreless rubber crawler includes: a steel-cord layer 5 that comprises a plurality of steel cords extending circumferentially along a crawler and is provided in a rubber elastic body extending in an endless manner; one or more reinforcing ply 8 layers that respectively comprise a plurality of cords and are provided on the outer peripheral side of the steel-cord layer; and lugs 9 formed on the outer peripheral face side of the rubber elastic body at prescribed intervals so as to act on the road surface. Each notched part 10 is provided in each region of at least one reinforcing ply 8 layer corresponding to at least one side edge part of each lug 9. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an endless coreless rubber crawler, and in particular, due to deformation of a side edge portion of a rubber elastic body when a side portion of the rubber crawler rides on a curbstone or the like with a lug. The present invention proposes a technique for preventing the occurrence of cracks in the lug and, by extension, the rubber elastic body.

  In a conventional coreless rubber crawler, for example, when riding on a curb or the like on its side, the rubber crawler, directly the side edge portion of the rubber elastic body, moves from the outer peripheral surface side to the inner peripheral surface side. A bending deformation in a warping direction is received, and in such a bending deformation, the rubber elastic body is subjected to stress concentration in the vicinity of the side edge of the reinforcing ply as a tension member embedded therein.

  In such a coreless rubber crawler, the reinforcing ply is embedded up to the vicinity of the region corresponding to the side edge portion of the lug, as illustrated in the transmission plan view of the relative position between the reinforcing ply and the lug in FIG. When riding on a curb or the like, especially when a large strain is generated due to bending deformation in the lug, stress concentrates on the end of the cord of the reinforcing ply located on the inner periphery of the lug, and so-called end cracks may occur. It was.

  For this reason, for example, as described in Patent Document 1, the tip of the bias cord in the rubber elastic body is bent to isolate the end of the cord from the portion where the strain concentrates, or as described in Patent Document 2, When the crawler body is bent in the crawler width direction and the reinforcing layer is bent in the crawler width direction so as to cover the end side of the reinforcing ply in the crawler width direction, the reinforcing layer is expanded in the crawler width direction. A technique for improving the lateral rigidity of the crawler by applying a reaction force has been proposed.

  However, since such a technique requires a bent portion and a canvas, there is a risk that the cost and weight of the crawler due to these members may increase.

JP 2006-151021 A JP 2002-321667 A

  Then, this invention is providing the rubber crawler which can suppress effectively generation | occurrence | production of the crack to the part corresponding to the side edge of a reinforcement ply of a rubber elastic body, without providing another member.

  The coreless rubber crawler according to the present invention includes a steel cord layer made of a plurality of steel cords extending along the crawler circumferential direction in a rubber elastic body extending endlessly, and a plurality of cords on the outer circumferential side thereof. And a lug that is formed on the outer peripheral surface side of the rubber elastic body at a predetermined interval and that acts on the road surface. A notch is provided in a region corresponding to at least one of the side edge portions.

More preferably, such a rubber crawler is provided with a notch in the outermost layer reinforcing ply.
Preferably, the notch portion is positioned across the lug in the crawler circumferential direction, and from the maximum width position of the reinforcing ply provided with the notch portion in the crawler width direction, from the wheel passing surface of the inner surface of the crawler, It arrange | positions in the range to the position corresponding to the outer end of a crawler width direction.

  By the way, a notch is provided in each side edge portion of the reinforcing ply, and the notches are arranged in a staggered manner.

  In the coreless rubber crawler of the present invention, the notch portion is provided in a region corresponding to at least one side edge portion of the lug of at least one reinforcing ply, so that it rides on the curbstone and the like, and the side edge portion of the lug Even when the periphery is greatly deformed, the cord end portion of the reinforcing ply does not exist at a position corresponding to the region, and the out-of-plane bending rigidity in the crawler width direction can be reduced. It is possible to effectively alleviate the strain concentration and stress concentration between the elastic body and the reinforcing ply to secure the circumferential tension of the reinforcing ply, and to suppress the end crack.

It is a section perspective view showing one embodiment of the coreless rubber crawler of the present invention. It is a permeation | transmission top view about the relative position of the reinforcement ply provided in the crawler of FIG. 1, and a lug. It is a permeation | transmission top view about the relative position of the reinforcement ply provided in the conventional metal coreless rubber crawler, and a lug. It is a figure which shows the state which the side edge part of the metal core less rubber crawler received bending deformation.

Hereinafter, the coreless rubber crawler according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional perspective view showing an embodiment of the present invention with respect to a part on the idler side, and FIG. 2 is a transparent plan view showing the relative positions of a reinforcing ply and a lug provided on the crawler in FIG. is there.

  In the figure, 1 is the entire coreless rubber crawler, 2 is the coreless rubber crawler body made of a rubber elastic body extending endlessly, and 3 is the circumferential direction on the inner peripheral surface of the crawler body 2. A driving protrusion disposed at a central portion in the crawler width direction at a predetermined pitch, and 4 an idler that rolls on the inner peripheral surface of the crawler body 2.

  In the crawler body 2, a steel cord layer 5 in which steel cords are embedded in parallel in the circumferential direction, and on the outer peripheral side thereof, two layers of cord crossing layers 6 made of cords inclined in the crawler circumferential direction in the figure. And a three-layer reinforcing ply 8 comprising a single radial layer 7 extending in the crawler width direction.

  Further, convex lugs 9 that act on the road surface are formed on the outer peripheral surface of the crawler body 2 at predetermined intervals in the circumferential direction.

  The crawler body 2, the driving projection 3 and the lug 9 can be made of, for example, a rubber material blended with ethylene-propylene-diene rubber having excellent weather resistance. Further, as the reinforcing ply 8, for example, a steel cord, It can be composed of a cord having high tensile strength such as an organic fiber cord.

  In this coreless rubber crawler 1, at least one reinforcing ply, in the figure, radial layer 7, at least one of the lugs, in the area corresponding to both side edge portions in the figure, notches 10 are formed in, for example, a staggered pattern. Provided.

  More preferably, in such a coreless rubber crawler 1, by providing the notch 10 in the radial layer 7 located at the outermost layer, the radial layer 7 which is the reinforcement layer closest to the lug side is perpendicular to the lug side. End cracks due to force in any direction can be suppressed.

  Preferably, the notch 10 has a crawler circumferential length c across the lug 9 and a crawler width length w from the maximum width position of the reinforcing ply provided with the notch 10. Within a range from a position 5 mm inward in the crawler width direction to a position corresponding to the outer end in the crawler width direction of the roller passing surface of the inner surface of the crawler, more preferably 100 in the crawler width direction from the side edge of the crawler. Position in the range of ~ 110 mm.

The notch 10 has a length c in the crawler circumferential direction across the lug 9 so as to cut out the radial layer 7 existing in the region corresponding to the lug 9 having high rigidity, and the rigidity of the entire region is reduced. While lowering, the crawler can be reinforced at the position where the end crack is difficult to occur in the radial layer 7 that is likely to be the starting point of the end crack.
The length w in the crawler width direction is 5 mm inward in the crawler width direction from the maximum width position of the reinforcing ply 8 provided with the notch 10, and the outer end in the crawler width direction of the roller passing surface on the inner surface of the crawler At the position in the range up to the corresponding position, the rubber crawler main body 2 is located on the outer side in the crawler width direction from the wheel passing surface, as shown in FIG. 4 where the side edge portion of the coreless rubber crawler has undergone bending deformation. The region is often subjected to bending deformation, and the strain concentration and stress concentration between the rubber elastic body and the reinforcement ply 8 in the region are alleviated and the wheel passing surface loaded by the wheel is reinforced with the reinforcement ply 8. By doing, generation | occurrence | production of an edge crack can be prevented.

By the way, by arranging the notches 10 at the side edge portions of the reinforcing ply in a staggered manner, the rigidity level difference between the lugs that are likely to be deformed by the out-of-plane bending input in the crawler width direction and the positions between the lugs that are difficult to deform This reduces vibration and rolling resistance.
In addition, it is preferable to provide the notch portion 10 on the outside of the mounting, and this position is particularly likely to ride on a curb or the like and to undergo out-of-plane bending deformation.

DESCRIPTION OF SYMBOLS 1 Whole coreless rubber crawler 2 Coreless rubber crawler body 3 Driving protrusion 4 Idler 5 Steel cord layer 6 Cord crossing layer 7 Radial layer 8 Reinforcement ply 9 Lug 10 Notch

Claims (4)

In a rubber elastic body extending in an endless manner, a steel cord layer made of a plurality of steel cords extending along the crawler circumferential direction, and one or more reinforcing plies made of a plurality of cords on the outer peripheral side, In a metal core-less rubber crawler comprising a lug that is formed at a predetermined interval on the outer peripheral surface side of the rubber elastic body and acts on the road surface,
A coreless rubber crawler characterized in that a notch portion is provided in a region corresponding to at least one side edge portion of a lug of at least one reinforcing ply.   The cored bar-less rubber crawler according to claim 1, wherein the notch is provided in the outermost layer reinforcing ply.   The notch is positioned across the lug in the crawler circumferential direction, and in the crawler width direction, from the maximum width position of the reinforcing ply provided with the notch to the inside of the crawler width direction from the position of 5 mm, the crawler inner surface rolls. The core metal-less rubber crawler according to claim 1 or 2, wherein the rubber passage is arranged in a range up to a position corresponding to the outer end in the crawler width direction of the ring passage surface.   The metal core-less rubber crawler according to any one of claims 1 to 3, wherein a notch is provided in each side edge portion of the reinforcing ply, and the notches are arranged in a staggered manner.

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