JPH0920271A - Structure of rubber crawler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an increased life for a rubber crawler by a method wherein the center of the bottom of a recessed part between protrusions for preventing dislocation of a wheel adjoining each other on the longitudinal direction of a rubber crawler is offset from the center of an overlapping part. SOLUTION: Protrusions 5 for preventing dislocation of a wheel are formed in such a state to protrude from the blade part 6 of a core 1 in a zigzagging manner toward the longitudinal direction of a rubber resilient body 2. A rubber resilient body 2 between the protrusions 5 and 5 of the adjoining cores 1 and 1 are previously removed to form a recessed part 7. When a roller or an idler is rolled over the protrusions 5 and 5, an inner frame is lodged between a pair of the projections 5 and 5 to prevent dislocation of a wheel. Further, expansion parts 8 and 9 are respectively formed right below the protrusions 5 and 5. Interference of the cores 1 and 1 with each other due to horizontal displacement of the cores 1 and 1 is prevented from occurring. The lengths of the expansion parts 8 and 9 are different from each other and the center of an overlapping part 10 between the expansion parts 8 and 9 is displaced by an offset amount C from the center of the bottom part 70 of the recessed part 7. This constitution disperses distortion and prevents the occurrence of the crank of the bottom 70 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field 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 improving the durability of a rubber crawler having an improved derailing performance.

[0002]

2. Description of the Related Art In recent years, there has been a demand for prevention of derailment between a rubber crawler and an idler or a roller. Derailment occurs when a core bar laterally shifts in the width direction of the rubber crawler. Is becoming known. This is because the core metal embedded in the rubber is laterally displaced within the range of rubber elasticity by an external force, and the idler or roller rides on the core metal in this displaced state, which causes wheel removal. Become.

In order to prevent the lateral displacement of the cored bar, a structure is considered in which adjacent cored bars embedded in the rubber contact and interfere with each other, and are adjacent to the cored bar embedded adjacently in the rubber. A bulging part is formed toward the cored bar, and when one cored bar exerts a lateral displacement force, the bulged parts collide with each other to minimize lateral displacement and prevent the wheel from derailing the chlora. It is a structure to give. That is, the above-mentioned bulging portion is configured such that at least a part thereof overlaps with each other when viewed in the width direction of the crawler, and the overlapping portions collide with each other.

By the way, in such a rubber crawler, a recess is provided in the rubber portion between the derailment preventing projections projecting from the inner peripheral surface, so that the winding resistance of the rubber crawler around the sprocket and the idler is reduced. It has become.
Therefore, the center of bending of the rubber crawler when it is wound around a sprocket or an idler or when riding on pebbles 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 crawler is removed in advance so that the bending of the rubber is concentrated in this recess and the winding resistance is reduced.

[0005]

[Problems to be Solved by the Invention]
Almost no research has been conducted on the relationship between the concave portion that serves as the bending center of the la and the bulging portion that imparts the lateral deviation prevention function.
That is, the overlapping portion of the bulging portion and the rubber around the overlapping portion are deformed by the tip of the bulging portion such as compression, tension, bending, etc., but to the concave portion which becomes the bending center of the rubber crawler. The fact is that the impact of is not taken into consideration.

Since the concave portion of the bending center has a thin rubber thickness at the bottom thereof, when the overlapping central portion and the bending central portion are at the same position, the deformation stress concentrates on this portion, Rubber deterioration is concentrated. For this reason, cracks are apt to occur at the bottom of the recess, especially during the reverse bending phenomenon, and as a result, the cored bar is exposed, resulting in a missing cored bar, which significantly shortens the life of the crowbar.

The present invention is intended to prevent the stress from being concentrated on the bottoms of the recesses formed between the protrusions, and to provide a structure in which the life of the rubber crawlers is improved.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is to provide an endless rubber elastic body that serves as a base of a rubber crawler, and a cored bar embedded laterally in the rubber elastic body at a constant pitch.
The core bar is composed of a row of steel cords which are embedded so as to surround the core bar. The core bar is provided with a pair of protrusions for preventing wheel removal, which protrude from the inner peripheral surface of the rubber crawler, and the adjacent core bars. A lateral swelling preventing bulging portion is provided, and the bulging portion is a rubber crawler having a configuration in which at least a part of the bulging portion overlaps when viewed in the crawler width direction, and is adjacent to the rubber crawler longitudinal direction. A recess is formed between the wheel release prevention projections and
The present invention relates to the structure of a rubber crawler, which is characterized in that the overlapping central portion of the bulging portion and the central portion of the bottom portion of the concave portion do not coincide with each other when viewed in the la width direction.

When the center of the concave portion formed between the protrusions protruding from the inner peripheral surface of the rubber crawler and the overlapping center of the bulging portion are aligned with each other, stresses such as compression and pulling at the time of winding are caused at the bottom of the concave portion. While concentrating on the center of the bulge, various stresses at the tip of the bulge also concentrate on the center of the overlapping part, that is, the center of the bottom of the recess, and the occurrence of cracks can be seen from the bottom of the recess. I will end up.

However, by offsetting the center of the bottom of the recess and the center of the overlapping portion as in the present invention, the concentration of stress is relieved, and the life of the rubber crawler is improved. It has become.
In other words, if only the recesses between the protrusions are considered, the strain of the rubber crawler tends to concentrate at the bottom of the recesses, while if only the bulging part is considered, the strain also concentrates near the center of the overlap region. Therefore, the present invention has a structure in which the two strain concentration regions do not coincide with each other, and the strain stress generated in the rubber is dispersed to improve the life of the rubber crawler.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a plan view of the inner side of the rubber crawler when the bottoms of the recesses between the protrusions and the center of the overlapped portion of the bulging portion are matched (offset amount C), and FIG. 6 is a sectional view of the protrusions. In the figure, 1 is a core metal, and 2 is a rubber elastic body that encloses the core metal. Reference numeral 3 is a steel cord row which is embedded in the rubber elastic body 2 so as to surround the cored bar. 4 is a rubber elastic body 2
It is a rubber lug formed on the outer periphery of. Now, the protrusions 5 project from the inner peripheral surface of the rubber elastic body 2 from the core metal 1. In this example, the protrusions 5 project in a zigzag manner from the wings 6 of the core metal 1 in the longitudinal direction of the rubber elastic body 2. ing. Then, the rubber elastic body between the protrusions 5 and 5 of the adjacent cored bars 1 and 1 is removed in advance to form the recess 7. The roller 30 or the idler rolls on the projections 5 and 5, and the inner collar 31 is sandwiched between the pair of projections 5 and 5 to prevent the falling.

In this example, bulges 8 and 9 are formed immediately below the protrusions 5 and 5, respectively, and the tips thereof are tapered end portions 8 ₁ and one is a bifurcated end 9 _1. This is what they engage with each other. Even when the cores 1 and 1 are laterally displaced by this engagement, the adjacent cores 1 and 1 interfere with each other to prevent the displacement.

[0013] The Gomukuro - La, upon the winding of the sprocket such as the recess 7 becomes the center of bending, the strain stress on the bottom 7 ₀ of the recess 7 will be concentrated. On the other hand, in the rubber crawler of this example, when the lateral displacement force is applied to the core metal 1, the overlapping portion 10 of the tips of the bulging portions 8 and 9 is formed.
Strain stress concentrates on the (engagement portion). However, in this example because there is overlap portion 10 of the bulge portion overlapping immediately below the recess 7 (offset 0), all distortion of the rubber elastic body 2 is concentrated in the bottom 7 ₀ of the recess 7 As a result, rubber deterioration is accelerated. In particular, Gomukuro - when reverse bending occurs in La, cracks were those become liable to the bottom 7 ₀ of the recess 7. In the figure, 11 is a central portion of the core metal 1, which is an engaging portion with a sprocket (not shown), 12
Is a sprocket engaging hole.

[0014]

In the Example of the present invention, shifting the center of the overlap portion 8 of the bottom 7 ₀ and bulging of the recess 7 as described above (offset C) Rubber strain in the bottom 7 ₀ of the recess 7 by This is to prevent the stress from being concentrated. In this example, for example, the lengths of the bulging portions 8 and 9 are adjusted so that the tips 8 and
Prevents promotion of rubber deterioration of the site by shifting the center of the overlapping portion 10 of the 9 than the bottom 7 ₀ of the recess 7, Gomukuro - is intended to improve the La lifetime.

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-mentioned rubber crawler is improved, and FIG. 2 is a sectional view of a protrusion. In this example, similarly to the case of FIGS. 5 to 6 described above, the bulging portions 8 and 9 are formed immediately below the protrusions 5, and these are engaged to engage the cored bars 1 and 1.
Although it has a function of preventing the lateral displacement of the bulge, the lengths of the bulging portions 8 and 9 are different from those described above, and as shown in the drawing, the center of the overlapping portion 10 of the bulging portions is the bottom portion 7 of the concave portion 7. _It is offset from ₀ (offset amount C). Thus, which has become possible to disperse the strain generated in the elastic body 2, Gomukuro - generation of a crack in the bottom 7 ₀ of the recess 7 also as a phenomenon of reverse bending or the like happened to La It almost never happened.

FIG. 3 shows a second example of the embodiment of the present invention, in which only the core metal is shown. Core 2
1 and 22, a short bulge portion 23 is formed on the staggered protrusion side of the projection 5, and a long bulge portion 24 is formed on the non-projection side of the protrusion 5. It is intended to prevent lateral displacement of the cored bars 21 and 22 by overlapping them when viewed in the width direction of the crawlers. In the figure, the core metal 2 adjacent to the tip of the protrusion 5
A concave portion 25 is formed between the concave portions 1 and 22, and a bottom portion 25 ₀ of the concave portion 25 exists at the center thereof. However, the center of the overlapping portion 26 of the bulging portions 23 and 24 is the bottom portion 2 in each case.
5 ₀ not overlap the (offset amount C), which concentrate the strain stress generated in the rubber elastic body by is prevented, here Gomukuro - La life is improved.

(Experimental Example) The effect of the present invention will be further described below with reference to an experimental example. FIG. 4 is an enlarged view of the core bar of the rubber crawler used for the experiment, and the width W of the rubber crawler is 400 m.
m, the pitch P between the metal cores is 74 mm, the length L ₁ of the top surface of the protrusion is 52 mm, the total length L ₂ of the bulging portion 24 is 83 mm, the gap between the protrusions is 22 mm, and the depth of the recessed portion provided in this gap is Has reached a depth of 5 mm from the wings. 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 was set to 6 mm by adjusting the length of the bulging portion 24. That is,
The center of the overlapping part is located at the center of the center of the core metal.
On the other hand, the conventional rubber crawler has an offset amount of 0.
mm, that is, the structure in which the central portion of the recessed portion and the central portion of the overlapping portion of the bulging portion 24 are aligned.

The test site was an unregulated ground road mixed with cobblestone and sand, and a rubber crawler was attached to a 5 ton airframe to conduct a continuous running test. The cobbles are set so that the reverse bending angle on this test path is 125 degrees at the maximum.

As a result of the test, in the rubber crawler of the present invention, cracks reaching the core bar did not occur even after running for 50 hours, whereas in the rubber crawler of the above-mentioned conventional structure. After 10 hours, a crack reaching the portion was generated in the recess due to swelling of the core metal.

[0020]

As described above, in the rubber crawler of the present invention, the occurrence of cracks is reduced, and the durability thereof 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 crawler of the present invention.

FIG. 2 is a sectional view of a protrusion of the rubber crawler of FIG.

FIG. 3 is a plan view of an inner peripheral side in which only a core metal in a second embodiment of the rubber crawler of the present invention is taken out.

FIG. 4 is a cross-sectional view of a core bar in a rubber crawler used in an experiment.

FIG. 5 is a plan view of an inner peripheral side of a conventional rubber crawler.

6 is a cross-sectional view of a protrusion in the rubber crawler of FIG.

[Explanation of symbols]

1, 21, 22 ... Mandrel, 2 ... Rubber elastic body, 3 ... Steel code row, 4 ... Rubber lug, 5 ... Projection, 6 ... Mandrel blade, 7, 25 ... ‥ recess 7 _0, 25 ₀ bottom of ‥‥ recess, 8,9,23,24 ‥‥ bulging part, overlapping part 10 ‥‥ bulging portion, the engagement portion of the 11 ‥‥ sprocket, 12 ‥‥ Sprocket engaging hole, 26 ... overlapped portion of bulging portion, 30 ... roller, 31 ... inner collar, C ... offset amount.

Claims (1)

[Claims] 1. An endless rubber elastic body serving as a base of a rubber crawler, a core metal laterally embedded in the rubber elastic body at a constant pitch, and a steel coil surrounding and embedding the core metal. -, The core bar is provided with a pair of de-ring prevention projections protruding from the inner peripheral surface of the rubber crawler, and lateral deviation prevention bulging portions extending toward the adjacent core bars.
The bulging portion is a rubber crawler having a structure in which at least a part of the bulging part is overlapped when viewed in the width direction of the crowbar.
(2) A recess is formed between the derailment prevention projections that are adjacent to each other in the longitudinal direction, and the overlapping center part of the bulging part and the bottom center part of the recess are not aligned with each other when viewed in the width direction of the roller. The structure of the rubber crawlers.