JP2006151193A - Rubber crawler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber crawler structured so that the rubber of the crawler on the outside of the core central part is prevented from peeling off, in which a rubber layer of properties not used in usual crawler is formed in that part. <P>SOLUTION: The rubber crawler 1 is formed from a rubber resilient band of endless form, cores 2 embedded in a rubber resilient piece at a certain pitch in the longitudinal direction, steel cords 4 embedded at the same time in such a way as surrounding a left and a right wing 3 of each core 2 on their outside, a rubber lug formed at the periphery, and an engagement part 5 with sprocket formed between each pair of adjoining cores, wherein rubber layers 10 and 11 having a higher hardness than that of the rubber crawler 1 are formed on the outside surface of the core central part pinched by the engagement part 5 with sprocket. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber track with improved durability.

  As shown in FIG. 1, a normal rubber crawler 1 has a core metal 2 embedded at a constant pitch in the longitudinal direction, and a steel cord 4 is embedded at the same time so as to surround a wing portion 3 of the core metal 2. . And the sprocket engaging part 5 is opened in the center part 2a between the adjacent metal cores 2 and 2. And the rubber lug 6 is normally formed in the form which covers the metal core 2 on the outer peripheral surface of the rubber crawler 1. The rubber elastic body constituting the rubber crawler 1 is usually different in the inner peripheral side rubber and the outer peripheral side rubber, and the inner peripheral side rubber has a hardness of 60 to 80 degrees (JIS A). The rubber has a hardness of 60 to 75 degrees.

  The outer peripheral side of the cored bar central portion 2a sandwiched between the sprocket engaging portions 5 is covered with a relatively thin rubber, but this thin rubber is the outer peripheral rubber as it is, and is usually vulcanized. In this case, the layer flows between the mold and the cored bar.

  However, the outer peripheral side of the central part of the rubber crawler, that is, the contact surface side near the sprocket hole in the central part of the rubber crawler, has the highest surface pressure, and in particular, the rubber is twisted and sheared due to running on rough terrain. This part of rubber is most susceptible to damage. A specific example of the form of damage is a rubber peeling phenomenon on the outer peripheral side of the central part of the cored bar. As a result, not only does the rubber crawler look bad, but also rust is generated in the core metal, and the rust and peeling generate gradual peeling of the core metal from the rubber and lack of rubber.

  For this reason, there is an example in which the lug height is set to the middle on the outer peripheral side of the central part of the core metal, but this is not perfect. In other words, the rubber lugs that are slightly smaller than the left and right rubber lugs may be formed on the outer peripheral side of the central portion of the core metal sandwiched between the sprocket engaging portions, but as described above, they are smaller than the left and right rubber lugs. In particular, since the width is small, there is an unavoidable drawback that rubber is peeled off or chipped from this portion when strain during running is concentrated.

  An object of the present invention is to provide a rubber crawler in which the rubber on the outer peripheral side of the central part of the core of the rubber crawler is prevented from being peeled off, and this part is not used for a normal rubber crawler. A rubber layer having a property is formed.

  The first gist of the present invention is that an endless rubber elastic band, a core metal embedded with a constant pitch in the longitudinal direction of the rubber elastic body, and the left and right wings of the core metal are surrounded on the outer periphery side at the same time. A rubber crawler in which an embedded steel cord, a rubber lug formed on the outer peripheral side, and an engaging portion with a sprocket are formed between adjacent core bars, sandwiched between the engaging portions with the sprocket. A rubber crawler in which a rubber layer having a hardness higher than that of the rubber constituting the rubber crawler is formed on the outer peripheral surface of the central portion of the core metal, wherein the hardness of the high hardness rubber layer is 80 to 95 degrees (JIS-A ).

  The second gist of the present invention is that an endless rubber elastic band, a core metal embedded with a constant pitch in the longitudinal direction of the rubber elastic body, and the left and right wings of the core metal are surrounded on the outer peripheral side at the same time. A rubber crawler in which an embedded steel cord, a rubber lug formed on the outer peripheral side, and an engaging portion with a sprocket are formed between adjacent core bars, sandwiched between the engaging portions with the sprocket. A rubber crawler in which a rubber layer having better adhesion than the rubber constituting the rubber crawler is formed on the outer peripheral surface of the central portion of the core metal, wherein the rubber layer having good adhesion is an NR rubber layer. .

  In the rubber crawler of the present invention, the outer peripheral side of the central part of the core metal is covered with a high hardness rubber layer or a rubber layer having good adhesiveness, which causes cracks in the rubber layer at such a site. It was possible to prevent and reduce the occurrence of peeling and rubber chipping.

  In the conventional rubber crawler, the rubber lug is not formed in the part facing the sprocket engaging part on the outer peripheral side of the central part of the core metal, and it is inevitably caused by the rubber flow filled in the mold at the time of molding the rubber crawler. It is only covered with the thin rubber layer which arises automatically, and the rubber layer of this part is not researched especially. However, the rubber at such a site is quickly peeled off from the core metal surface. However, the influence of rubber peeling at such a part on the life of the rubber crawler is relatively large, and the present invention aims to reduce this phenomenon and improve the life of the rubber crawler.

  In the present invention, it is intended to actively cover the outer peripheral side of the central portion of the core metal with a specific rubber. In the first invention, the core is covered with a high hardness rubber layer. It covers the surface of gold and improves cut resistance and reduces the phenomenon of rubber peeling and rubber chipping. It is sufficient that the rubber layer has a thickness of 2 to 4 mm.

  In the second aspect of the invention, the outer surface of the central portion of the core metal is covered with an NR rubber layer instead of the high hardness rubber layer. For this reason, the NR rubber having good adhesiveness and the metal core are firmly bonded, and the rubber is hardly peeled off. The NR rubber refers to rubber having an NR rubber component of 60% or more, and is blended with a normal vulcanizing agent, vulcanization accelerator, reinforcing agent, softening agent and the like.

  Such high-hardness rubber or NR-based rubber forms an unvulcanized rubber sheet of such rubber, and this sheet is attached to cover the outer peripheral side of the central portion of the core metal when molding a rubber crawler, and other unvulcanized rubber sheets. What is necessary is just to vulcanize-mold with rubber.

  Hereinafter, the present invention will be further clarified with reference to the drawings. FIG. 2 is a cross-sectional view of the rubber crawler according to the first aspect of the present invention, and the rubber crawler is continuous on the front and back of the paper. Reference numeral 1 denotes a rubber material constituting the rubber crawler, and 2 denotes a metal core embedded at a constant pitch. And the steel cord 4 is embed | buried in the longitudinal direction of a rubber crawler surrounding the wing | blade part 3 of the metal core 2 from the outer peripheral side. 5 is a sprocket engaging portion, and 6 is a rubber lug formed on the outer peripheral surface of the rubber crawler.

  A 4 mm thick rubber layer 10 having a hardness of 95 degrees is formed on a portion (a peripheral side of the central portion of the core metal) 2a facing the two sprocket engaging portions 5 of the core metal.

  FIG. 3 shows a method of molding a rubber crawler according to the present invention. An unvulcanized rubber sheet 21 that forms the inner peripheral side of the rubber crawler on the surface of the lower mold A that defines the inner peripheral side of the rubber crawler. Placed on this, the core 2, the steel cord 4 whose front and back are coated with unvulcanized rubber 22 on the wing 3 of the core 2, and the high hardness rubber layer 10 is formed on the outer peripheral side of the core 2 a. The unvulcanized rubber sheet 23 is overlapped. Then, the rubber crawler outer peripheral side and the unvulcanized rubber 24 forming the lug are overlapped, and pressure and heat molding are performed by the upper mold B that partitions the outer peripheral side of the rubber crawler.

  In a normal rubber crawler, the rubber on the outer peripheral side of the core metal central portion 2a is composed of the rubber component constituting the outer peripheral side of the rubber crawler as it is, but this rubber layer is easily peeled off. Thus, this damage causes a cut flaw to grow, but in this embodiment, the occurrence of cut flaw on the rubber is extremely small by making the rubber layer 10 a high hardness rubber layer. became.

  In the second invention, an NR rubber layer 11 is used instead of the high hardness rubber layer 10 described above. For this reason, the rubber layer 11 and the outer peripheral surface of the cored bar central portion 2a are firmly bonded, and the occurrence of peeling of the rubber 11 is extremely reduced. The formation of the NR rubber layer 11 is the same as in the above example.

  The present invention has the structure as described above, and the improvement in the durability of the rubber crawler embedded with the above-described cored bar is remarkable and can be used for many rubber crawlers.

FIG. 1 is a cross-sectional view of a conventional rubber crawler. FIG. 2 is a cross-sectional view of the rubber crawler of the present invention. FIG. 3 is a cross-sectional view showing the manufacturing process of the rubber crawler of the present invention.

Explanation of symbols

1. Rubber crawler,
2. Core metal,
2a ... the central part of the core,
3. Wings of core metal,
4. Steel code,
5 ... Sprocket engaging part,
6. Rubber rug,
10, 11 ... Rubber layer covering the outer peripheral surface of the central part of the cored bar,
21 ... an unvulcanized rubber sheet forming the inner peripheral side of the rubber track;
22 ... unvulcanized rubber covering the steel cord,
23. An unvulcanized rubber sheet for forming a rubber layer covering the outer peripheral surface of the central portion of the cored bar,
24. An unvulcanized rubber sheet forming the outer peripheral side of the rubber track;
A, B ... Mold.

Claims (4)

  An endless rubber elastic band, a core metal embedded at a constant pitch in the longitudinal direction of the rubber elastic body, and a steel cord embedded simultaneously surrounding the left and right wings of the core metal on the outer peripheral side A rubber crawler in which an engaging portion with a sprocket is formed between adjacent rubber cores and a rubber lug formed on the outer peripheral side, on the outer peripheral side of the central portion of the core metal sandwiched between the engaging portions with the sprocket. A rubber crawler characterized in that a rubber layer having a hardness higher than that of rubber comprising a rubber crawler is formed on the surface.   2. The rubber crawler according to claim 1, wherein the hardness of the high hardness rubber layer is 80 to 95 degrees (JIS-A).   An endless rubber elastic band, a core metal embedded at a constant pitch in the longitudinal direction of the rubber elastic body, and a steel cord embedded simultaneously surrounding the left and right wings of the core metal on the outer peripheral side A rubber crawler in which an engaging portion with a sprocket is formed between adjacent rubber cores and a rubber lug formed on the outer peripheral side, on the outer peripheral side of the central portion of the core metal sandwiched between the engaging portions with the sprocket. A rubber crawler characterized in that a rubber layer having better adhesion than a rubber comprising a rubber crawler is formed on the surface.   4. The rubber crawler according to claim 3, wherein the rubber layer having good adhesiveness is an NR rubber layer.

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