JP3744976B2 - Structure of rubber track - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber crawler used in a traveling device such as a construction machine, and more particularly, to improve the durability of a rubber crawler with improved derailment performance.
[0002]
[Prior art]
In recent years, there has been a demand for prevention of derailment between a rubber crawler and an idler or a roller, and it has been found that derailment occurs when the core metal is laterally displaced in the width direction of the rubber crawler. Yes. This is because the cored bar embedded in the rubber is displaced laterally within the range of rubber elasticity by the external force, and the idler or the roller rides on the shifted cored bar and the wheel is removed as it is. Become.
[0003]
In order to prevent lateral displacement of the core metal, a structure in which adjacent core bars embedded in the rubber contact and interfere with each other is considered, and the core metal adjacent to the core metal embedded adjacent to the rubber has been considered. A structure that forms a bulging part toward one side, and when one core metal exerts a lateral displacement force, the bulging parts collide with each other to reduce the lateral displacement as much as possible and to provide a function to prevent the removal of the crawler. It has become. That is, the above-described bulging portions are configured such that at least a portion thereof overlaps when viewed in the width direction of the crawler, and the overlapping portions collide with each other.
[0004]
By the way, such a rubber crawler is provided with a concave portion in a rubber portion between the protrusions for preventing the wheel from protruding from the inner peripheral surface, thereby reducing the winding resistance of the rubber crawler around the sprocket or idler. Yes. Therefore, the center of bending when the rubber crawler is reversely bent when it is wound around a sprocket or idler or when riding on a pebble or the like is the center of the bottom of this recess. That is, the rubber between the protrusions protruding from the inner peripheral surface of the rubber tracker is removed in advance, thereby concentrating the bending of the rubber in the concave portion and reducing the winding resistance.
[0005]
[Problems to be solved by the invention]
Now, there has been little research on the relationship between the concave portion serving as the bending center of the rubber crawler and the bulging portion imparting the above-described lateral shift prevention function. That is, the overlapping part of the bulging part and the surrounding rubber are subjected to deformation force such as compression, pulling, bending, etc. by the tip part of the bulging part, but to the concave part which becomes the bending center of the rubber crawler described above. The actual situation is that no consideration is given to the effects of.
[0006]
Now, since the rubber thickness is thin at the bottom of the concave portion at the center of bending, when this overlapping center portion and the bending center portion are at the same position, deformation stress concentrates on this portion, and the rubber deteriorates. Concentrate. For this reason, cracks are likely to occur at the bottom of the recess, particularly during the reverse bending phenomenon. As a result, the cored bar is exposed, leading to a loss of the cored bar, which significantly shortens the life of the crawler.
[0007]
The present invention provides a structure in which the stress is not concentrated on the concave portion formed between the protrusions, particularly at the bottom, and the life of the rubber crawler is improved.
[0008]
[Means for Solving the Problems]
The gist of the present invention is that an endless rubber elastic body serving as a base of a rubber crawler, a core bar embedded side by side with a constant pitch in the rubber elastic body, and a steel that surrounds and is embedded in the core bar. The core bar is provided with a pair of anti-rolling protrusions protruding from the inner peripheral surface of the rubber crawler, and a lateral slip prevention bulging portion extending toward the adjacent core bar, The bulging portion is a rubber crawler that is formed immediately below the protrusion for preventing wheel disengagement and has a configuration in which at least a part thereof overlaps when viewed in the width direction of the crawler, in the longitudinal direction of the rubber crawler. A concave portion is formed between the adjacent protrusions for preventing wheel removal, and the overlapping central portion of the bulging portion and the bottom central portion of the concave portion are not matched with each other when viewed in the width direction of the crawler. This relates to the structure of the rubber track.
[0009]
When the center of the recess formed between the protrusions projecting from the inner peripheral surface of the rubber crawler and the overlapping center of the bulging portion are matched, the stress such as compression and tension at the time of winding is at the center of the bottom of the recess. On the other hand, various stresses at the tip of the bulging portion are also concentrated at the center of the overlapping portion, that is, at the center of the bottom of the recess, and the occurrence of cracks is observed from the bottom of the recess.
[0010]
However, by offsetting the center of the bottom of the recess and the center of the overlapping portion as in the present invention, the stress concentration is alleviated, and the life of the rubber crawler is improved here. Is. In other words, if only the recesses between the protrusions are considered, the strain of the rubber crawler tends to concentrate on the bottom of the recesses, whereas if only the bulging part is considered, the strains are also concentrated near the center of the overlapping area. Therefore, the present invention has a structure in which the strain concentration sites of both are not matched, and the strain stress generated in the rubber is dispersed to improve the life of the rubber crawler.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 4 is a plan view of the inner side of the rubber crawler when the bottom of the concave portion between the protrusions coincides with the center of the overlapping portion of the bulging portion (offset amount C), and FIG. 5 is a cross-sectional view of the protrusion.
In the figure, 1 is a metal core, and 2 is a rubber elastic body containing the metal core. Reference numeral 3 denotes a steel cord row which surrounds the core metal and is embedded in the rubber elastic body 2. Reference numeral 4 denotes a rubber lug formed on the outer periphery of the rubber elastic body 2. Now, the protrusion 5 protrudes from the inner peripheral surface of the rubber elastic body 2 from the core metal 1, and in this example, the protrusion 5 protrudes in a zigzag manner from the wing part 6 of the core metal 1 toward the longitudinal direction of the rubber elastic body 2. ing. Then, the rubber elastic body between the protrusions 5 and 5 of the adjacent core bars 1 and 1 is removed in advance to form a recess 7. The roller 30 or idler rolls on the projections 5 and 5, and the inner flange 31 is sandwiched between the pair of projections 5 and 5 to prevent the roll-off.
[0012]
In this example, the bulging portions 8 and 9 are formed immediately below the protrusions 5 and 5, respectively, and the tips are tapered ends 81 and one is a bifurcated end 91, which are engaged. It's something to meet. Even when the core bars 1 and 1 are laterally shifted by this engagement, the adjacent core bars 1 and 1 interfere with each other to prevent the shift.
[0013]
When the rubber crawler is wound around a sprocket or the like, the recess 7 becomes the center of bending, and the strain stress is concentrated on the bottom 70 of the recess 7. On the other hand, in the rubber crawler of this example, when a lateral displacement force is applied to the core metal 1, strain stress concentrates on the overlapping portion 10 (engagement portion) at the tip of the bulging portions 8 and 9.
However, in this example, there is an overlapping portion 10 of the bulging portion that overlaps directly below the concave portion 7 (offset amount 0), so that all the strain of the rubber elastic body 2 is concentrated on the bottom portion 70 of the concave portion 7. As a result, rubber deterioration is promoted. In particular, when reverse bending occurs in the rubber crawler, cracks are likely to occur at the bottom 70 of the recess 7.
In the figure, reference numeral 11 denotes a central portion of the cored bar 1, an engaging portion with a sprocket (not shown), and 12 a sprocket engaging hole.
[0014]
【Example】
In the present invention, the rubber strain stress is concentrated on the bottom 70 of the recess 7 by shifting the bottom 70 of the recess 7 and the center of the overlapping portion 8 of the bulging portion (offset amount C) as described above. In this example, for example, the length of the bulging portions 8 and 9 is adjusted, and the center of the overlapping portion 10 of the tip 8 or 9 is shifted from the bottom 70 of the concave portion 7, thereby It is intended to prevent the deterioration of rubber and improve the life of the rubber crawler.
[0015]
FIG. 1 is a plan view of an inner peripheral side in a first example showing an embodiment of the present invention in which the above-described rubber crawler is improved, and FIG. In this example, as in the case of FIGS. 4 to 5 described above, the bulging portions 8 and 9 are formed immediately below the protrusion 5 and engaged to prevent the lateral displacement of the core bars 1 and 1. Although the length of the bulging portions 8 and 9 is different from the above, the center of the overlapping portion 10 of the bulging portion is shifted from the bottom portion 70 of the concave portion 7 as shown in the figure (offset amount). C).
This makes it possible to disperse the strain generated in the rubber elastic body 2, and even if a phenomenon such as reverse bending occurs in the rubber crawler, almost no crack is generated in the bottom 70 of the recess 7. It did not occur.
[0016]
[0017]
(Experimental example)
Hereinafter, the effect of the present invention will be further described with experimental examples.
FIG. 3 is an enlarged view of the core of the rubber crawler in which the experiment was performed. The width W of the rubber crawler was 400 mm, the pitch P between the cores was 74 mm, the length L1 of the top surface of the protrusion was 52 mm, and the bulge The total length L2 of the portion 24 is 83 mm, the gap between the protrusions is 22 mm, and the depth of the recess provided in the gap reaches a depth of 5 mm from the wing portion. The offset amount C between the central portion of the concave portion and the central portion of the overlapping portion of the bulging portion 24 is 6 mm by adjusting the length of the bulging portion 24. That is, the center of the overlapping portion is located at the center of the core metal center. On the other hand, the conventional rubber crawler has a structure in which the offset amount is 0 mm, that is, the central portion of the recessed portion and the central portion of the overlapping portion of the bulging portion 24 are matched.
[0018]
The experimental place was an artificial rough terrain mixed with cobbles and sand. A rubber crawler was mounted on a 5 ton airframe and a continuous running test was conducted. The cobblestone is set so that the maximum angle of reverse bending on this test path is 125 degrees.
[0019]
As a test result, in the rubber crawler of the present invention, cracks reaching the core metal did not occur even after running for 50 hours, whereas in the rubber crawler having the conventional structure described above, 10 After a time, cracks reaching the part due to the expansion of the core metal occurred in the concave part.
[0020]
【The invention's effect】
In the rubber track of the present invention, the occurrence of cracks is reduced as described above, and the durability is remarkably improved.
[Brief description of the drawings]
FIG. 1 is a plan view of an inner peripheral side in a first embodiment of a rubber track according to the present invention.
FIG. 2 is a cross-sectional view of a protrusion in the rubber track of FIG.
FIG. 3 is a cross-sectional view of a rubber bar used in the experiment with a cored bar.
FIG. 4 is a plan view of an inner peripheral side of a conventional rubber crawler.
FIG. 5 is a cross-sectional view of a protrusion in the rubber track of FIG.
[Explanation of symbols]
1 ... Core,
2. Rubber elastic body,
3 ... Steel code line,
4 ... Rubber lugs,
5 ... Projections,
6 ...... Core metal wings,
7: Recess,
70 ... the bottom of the recess,
8, 9 ... bulge,
10 ... Overlapping part of the bulge,
11... Engaging part with sprocket,
12 ... Sprocket engagement hole,
30 Roller,
31 ... Inner pot,
C: Offset amount.

Claims (1)

An endless rubber elastic body serving as a base of a rubber crawler, a core metal embedded side by side with a fixed pitch in the rubber elastic body, and a steel cord row that surrounds and is embedded in the core metal, the core The gold is provided with a pair of anti-roll-out projections protruding from the inner peripheral surface of the rubber crawler and a lateral-slip-preventing bulging portion extending toward the adjacent cored bar. The crawler is a rubber crawler that is formed immediately below and at least partially overlaps when viewed in the crawler width direction, wherein the protrusion for preventing wheel removal is longer in the longitudinal direction of the rubber crawler than the wing portion of the cored bar. Projected in a zigzag pattern, formed with recesses between adjacent anti-roll-off projections, and configured so that the overlapping center part of the bulging part and the bottom center part of the recess did not match when viewed in the crawler width direction Rubber rubber characterized by Structure of over La.

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