JP2006159942A - Endless structure for rubber crawler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cause no peeling off of a joint surface of a rubber and to realize enhancement of durability of a rubber crawler by vulcanizing it on a joint border surface of the rubber, i.e., an outer peripheral side than a main cord through an NR based unvulcanized rubber sheet in an endless structure of the rubber crawler. <P>SOLUTION: In the endless structure for the rubber crawler, the inside and the outside of both ends of a rubber crawler substrate are made to the unvulcanized rubber or a slightly heated rubber while clamping a main cord, both ends of the main cord are superposed and the unvulcanized rubber or the slightly heated rubber part are vulcanized. An NR based unvulcanized rubber sheet is clamped to a rubber joint border surface, i.e., at least an outer peripheral side of the main cord and is vulcanized. A rubber elastic body 1, a core metal 2, a main cord 3, both ends 3a, 3b of the main cord, a lug 4, a lug unvulcanized rubber part 4a, a lug vulcanized rubber part 4b, a lug 40 molded by 4a and 4b and the NR based unvulcanized rubber sheet 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an endless structure of a rubber track.

  As a structure of the rubber crawler, there are a rubber crawler with a core metal in which a core metal is embedded at a constant pitch in the longitudinal direction, and a so-called core metal-less rubber crawler in which the core metal is not embedded.

  Hereinafter, the present invention will be described by taking the former rubber crawler as a representative. In the former rubber crawler, a core metal is embedded with a constant pitch in the longitudinal direction, and a main cord is embedded at the same time by surrounding the wing portion of the core metal from the outside. A lug is formed. An endless structure may be adopted from the beginning of molding to make the rubber crawler endless. Normally, however, an endless rubber elastic body is molded and then both ends are joined to form an endless structure. There are many things to do.

  FIG. 1 illustrates this conventional technique. Reference numeral 1 is a long and long rubber elastic body, 2 is a metal core, 3 is a main cord, and 4 is a lug. Then, this portion is re-vulcanized with the ends 3a and 3b of the main cord overlapped to form an endless structure. In this case, the ends of the ends 3a and 3b of the main cord 3 are not placed inside and outside. A rubber part that has not been completely vulcanized (hereinafter referred to as an unvulcanized rubber part) that has been vulcanized or slightly heated is attached. In this state, both ends 3a and 3b of the main cord are overlapped. After that, this part is completely vulcanized to form an endless structure.

  And as shown in FIG. 2, the joining site | part of both rubbers has a structure joined especially in the outer peripheral side in the position of a lug. This is to try to join at a portion having as much rubber as possible. For this reason, when superposed, the main cord 3a on the outer peripheral side has about half the tip of the unvulcanized rubber portion. On the other hand, the main cord 3b on the inner peripheral side is formed with a lug 4b which is bonded to the lug 4a and vulcanized so as to form a normal lug 4.

  Therefore, when the endless structure is adopted, the lug 40 is formed by bonding the vulcanized side (4b) and the unvulcanized side (4a).

  In such a lug 40, the bonding strength tends to be insufficient, and the peeling phenomenon at the boundary surface of the rubber joint on the outer peripheral side of the main cord on the pulling side is often seen. Sometimes the lifespan was shortened. Of course, the same applies to the case where the boundary surface of the rubber joint is not the lug portion, and the peeling phenomenon tends to further increase because such a portion has a small amount of rubber. Furthermore, it goes without saying that such a phenomenon has no relation to the presence or absence of the cored bar, and any peeling phenomenon is brought about.

  The present invention has been made in view of the prior art as described above, and an object thereof is to prevent peeling from a rubber joint boundary when a rubber crawler is endless.

  The gist of the present invention resides in a rubber crawler base having a long and long rubber elastic body, a main cord embedded in the longitudinal direction, and a lug formed on the outer surface, and the rubber crawler. In a rubber crawler endless structure in which both ends of the base are sandwiched between main cords and the inside and outside are unvulcanized rubber portions, both ends of the main cord are overlapped and the unvulcanized rubber portions are vulcanized, -An endless structure of a rubber crawler, characterized in that an NR-based unvulcanized rubber sheet is sandwiched and vulcanized at a rubber joint interface on the outer peripheral side of the cable.

  In particular, the NR-based unvulcanized rubber sheet has a rubber crawler endless structure in which the amount of NR rubber is 60% or more.

  The present invention has an endless structure of a rubber tracker, and vulcanizes the rubber joint boundary surface on the outer peripheral side from the main cord of the rubber tracker via an NR-based unvulcanized rubber sheet. Separation of the joint surface does not appear, and the durability of the rubber crawler is improved.

  In the endless structure of the rubber track of the present invention, the bonding boundary of rubber is adhesion between vulcanized rubber and unvulcanized rubber, and the bonding strength between the two is relatively weak. Therefore, peeling appears at the rubber joint boundary on the rubber pull side of the rubber crawler. For this reason, in the present invention, an NR-based unvulcanized rubber sheet is interposed at the joint surface between the two and vulcanized and bonded in this state. The strength of the joint surface is remarkably improved, and at the joint boundary. Is no longer peeled off.

  Although the present invention is as described above, it goes without saying that an NR-based unvulcanized rubber sheet can also be interposed at other rubber bonding interfaces.

  Specific examples of NR-based unvulcanized rubber are NR rubber 60 to 100 parts, SBR 40 to 0 parts, and fillers necessary for this, for example, carbon black (HAF) 50 to 60 parts, sulfur 2 -4 parts, 5-10 parts of plasticizers, 2-5 parts of anti-aging agent are included. Further, it is sufficient that the thickness of the NR-based unvulcanized rubber sheet is about 2 to 5 mm. As for the properties after vulcanization of the unvulcanized rubber sheet, those having a rubber hardness of 60 to 75 degrees (JIS A) are preferable.

  Hereinafter, the present invention will be described in more detail with reference to examples. FIG. 3 is a view showing an endless structure of the rubber track of the present invention. Note that the same reference numerals as those already described are omitted here. The rubber track substrate of the present invention comprises a long and long rubber elastic body 1, a core metal 2, a main cord 3, and a lug 4. The center of the long rubber elastic body 1 is vulcanized into a rubber crawler shape, and the rubber elastic body 1 and each lug 4 in this portion are already vulcanized. However, at both ends 3a and 3b of the main cord that are overlapped when endless, the lug 4a0 is formed on the 3a side, and the half of the lug 4a is formed on the end of the main cord 3a with unvulcanized rubber. Yes. On the other hand, the shape of the inner peripheral side of the rubber crawler is formed of unvulcanized rubber on the 3b side, and the shape 4b of the half of the lug is vulcanized and formed in front of it.

  FIG. 4 is a view of the endless structure, in which the main cords 3a and 3b of the rubber track base are overlapped. At this time, the half vulcanized lug 4b on the 3b side and the half lug 4a in the unvulcanized state on the 3a side form a joint boundary surface. Accordingly, the NR-based unvulcanized rubber sheet 10 is sandwiched between the joint surfaces, and the entire laminated body is heated and vulcanized and bonded while maintaining this state.

  The composition of the used NR-based unvulcanized rubber sheet 10 is NR 80 parts, SBR 20 parts, HAF 45 parts, aroma oil 13 parts, sulfur 3 parts, other anti-aging agents, vulcanization accelerators, etc. A filler is blended, and this is kneaded by a two-sider to obtain an unvulcanized rubber sheet having a thickness of 4 mm.

  The obtained rubber crawler was used for running, but no peeling phenomenon at the joining interface was observed. As described above, the present invention can be applied to an endless structure of a rubber crawler of any shape, and can be applied not only to a rubber crawler with a cored bar but also to an endless structure of a coreless rubber crawler. Extremely wide.

FIG. 1 is a diagram showing a conventional rubber crawler endless method. FIG. 2 is a view showing an endless structure of a rubber crawler obtained by the conventional method of FIG. FIG. 3 is a diagram showing an endless method of the rubber track according to the present invention. FIG. 4 is a view showing an endless structure of a rubber crawler obtained by the method of the present invention shown in FIG.

Explanation of symbols

1. Ended and long rubber elastic body,
2. Core metal,
3. Main code,
3a, 3b ... both ends of the main cord,
4 ... Rug,
4a ... Rug unvulcanized rubber part,
4b ... Rug vulcanized rubber part,
40 ... Lugs formed from 4a and 4b,
10 NR-based unvulcanized rubber sheet.

Claims (3)

  A rubber crawler base having a long and elastic rubber body, a main cord embedded in the longitudinal direction, and a lug formed on the outer surface, and both ends of the rubber crawler base are connected to the main core. A rubber crawler formed by unwrapping the inside and outside of the rubber with a cord between them and heating the main cord on both ends and vulcanizing the unvulcanized rubber or the rubber portion heated slightly. An endless structure for a rubber crawler, characterized in that an NR-based unvulcanized rubber sheet is sandwiched and vulcanized at least on a rubber joint interface on the outer peripheral side of the main cord.   2. An endless structure of a rubber crawler according to claim 1, wherein the NR-based unvulcanized rubber sheet has an NR rubber amount of 60% or more.   2. An endless structure of a rubber crawler according to claim 1, wherein the NR-based unvulcanized rubber sheet has an NR rubber amount of 60% or more and an SBR rubber amount of 40% or less.

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