JP2000326879A - Rubber crawler excellent in rectilinear advancing property and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rectilinear advancing property of a rubber crawler by alternately arranging an S-twist cord group and a Z-twist cord group in a width direction of a rubber crawler in steel cords. SOLUTION: This rubber crawler is a planar sheet 10a that S-twist cords 1 and Z-twist cords 2 are alternately arranged in steel cords as a tensile body. The planer sheet 10a is formed by alternately arranging the S-twist cords 1 and the Z-twist cords 2, holding the steel cords 1 and 2 by unvulcanized rubber sheets excellent in adhesive property as cover rubber 3, 4 from upper and lower sides of these steel cords 1 and 2 and performing pressing along these cords 1, 2 in the longitudinal direction of the steel cords 1, 2 by a stitcher. The planar sheet 10a cancels a twist by alternately arranging a steel cord group having a tendency to twist to one side for a steel cord having a tendency to twist to the other side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber crawler having a steel cord serving as a tensile member having an overlap joint structure, and more particularly, to a rubber crawler having good straightness during use of the rubber crawler. Things.

[0002]

2. Description of the Related Art Since a rubber crawler is used for traveling with a large tension applied between a sprocket and an idler during traveling, a steel cord is continuously embedded as a tensile member in the longitudinal direction of the rubber crawler. However, this steel cord is formed by twisting a thin wire and further having, for example, a 7 × 7 structure. Usually, an S-twisted or Z-twisted steel cord is used alone. Therefore, a rubber crawler in which steel cords are arranged in a horizontal direction as a tensile member may generate a rightward or leftward force depending on the twisting direction, which may cause a problem in the straightness of the rubber crawler.

[0003] JP-A-8-320 as one of the prior art
Japanese Patent No. 051 proposes a structure in which rubber crawlers are arranged endlessly with S-twisted and Z-twisted steel cords at the center in the width direction and buried in rubber. In addition, it is not only difficult to arrange steel cords endlessly in rubber, but also to wrap separate steel cords on the left and right sides, the production equipment becomes extremely large, which is not practical.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional technique, and has as its object to provide a rubber track of high straightness at low cost.

[0005]

According to a first aspect of the present invention, a steel cord extending in the longitudinal direction of a rubber elastic body having ends is embedded in a row in the width direction, and the steel cords projecting from both ends are overlapped. A rubber crawler having a joint portion, wherein the steel cord has a structure in which a group of S-twisted cords and a group of Z-twisted cords are alternately arranged in the width direction of the rubber crawler. There is one or a plurality of cords, and the length of the overlap portion is arbitrarily determined by the expected tension.

A second aspect of the present invention is to obtain a plate-shaped sheet in which S-twisted steel cords and Z-twisted steel cords are alternately arranged side by side and covered with unvulcanized rubber sheets from above and below. Is set in a mold for molding a rubber crawler, and after filling the unvulcanized rubber in the mold, pressurizing and heating are performed to obtain a rubber elastic body having a steel cord embedded therein and protruding from both ends. This is a method of manufacturing a rubber crawler that overlaps steel cords, fills unvulcanized rubber into these parts, and pressurizes and heats them to form an endless rubber crawler with excellent straightness. Each cord group consists of one or more cords. It is.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A rubber track according to the present invention has a steel cord overlap joint structure,
It is obtained by alternately arranging steel cords twisted in the direction and steel cords twisted in the Z direction in the width direction of the rubber track.

[0008] In the case of the steel cord having the endless structure of the rubber track in the above-mentioned conventional example, it is necessary to wind two S twists and two Z twists on a drum at the same time, which is extremely low in productivity. If you have a rubber crawler using a plate-shaped molded product made by arranging a large number of steel cords in advance and coating rubber with a calendar, etc., it has good productivity and steel cords Since the S-twist and the Z-twist are almost equally arranged on the left and right with respect to the longitudinal direction of the rubber crawler, a rubber crawler with good straightness can be obtained. With regard to the steel cord of the present invention, the number of S-twisted and Z-twisted cord groups is basically the same, and the number of these cords is one or more.

[0009]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. FIG. 1 shows a sheet-like sheet 10a in which S-twist and Z-twist are alternately arranged every other steel cord as a tensile member.
In this example, S-twisted steel cords 1 and Z-twisted steel cords 2 are alternately arranged, and sandwiched between the unvulcanized rubber sheets having good adhesiveness as cover rubbers 3 and 4 from above and below, Using a stitcher (not shown), the cords 1 and 2 are moved in the longitudinal direction of the steel cords 1 and 2.
To form a plate-like sheet 10a.

FIG. 2 shows a plate-like sheet 10b in which two S-twisted steel cords 1 and two Z-twisted steel cords are alternately arranged and sandwiched between cover rubbers 3 and 4.

FIG. 3 shows a modification of FIG. 2, in which two S-twisted steel cords 1 and two Z-twisted steel cords 2 are grouped together and arranged alternately. 5 shows a plate-like sheet 10c inserted.

As described above, the plate-shaped sheet is formed by alternately arranging one or more S-twisted steel cords and Z-twisted steel cords. A steel cord group that tends to twist to the side is arranged alternately to cancel this twist, and when these are buried in a rubber crawler as a tensile member in the longitudinal direction, they extend in the left and right width directions. Is significantly reduced, and the straightness of the rubber crawler is ensured.

FIGS. 4 and 5 are cross-sectional views of the rubber crawler 10 using the plate-like sheet 10b, in which the plate-like sheet 10b is embedded around the core metal 11 and vulcanized. And, as the endless joint part 20, the tips of the steel cords 1 and 2 in the plate-like sheet 10b are
In this case, an unvulcanized rubber is filled in this portion and then re-vulcanized to form a continuous body. The degree of such overlap depends on the size of the rubber crawler, but is preferably within the above-described range. If the overlap is too short, it will fall out during use, and if the degree is large, the rigidity of this part will be conspicuous. It becomes like this. In the figure, reference numeral 12 denotes a rubber lug formed on the outer periphery of the rubber crawler, and the cover rubbers 3 and 4 in the plate-like sheet 10b are vulcanized together with other unvulcanized rubber and are completely integrated.

The plate-like sheets 10a, 10b,.
The steel cords 1 and 2 of the S-twist and the Z-twist are formed in groups of one or more and arranged alternately, and one or more groups are selected as the number of the groups.

In the above example, a cross section of a rubber crawler in which a core is embedded in rubber is shown. However, although not shown, it can be naturally used for a rubber crawler in which a core is not embedded. In this case, it is needless to say that the S-twisted steel cord group and the Z-twisted steel cord group can be arranged one by one in the width direction of the rubber track.

[0016]

According to the rubber crawler of the present invention, it is possible to provide the rubber crawler with straightness, and it is possible to manufacture the rubber crawler at an extremely low cost as compared with the conventional endless winding. Was.

[Brief description of the drawings]

FIG. 1 is a plate-like sheet 10a in which S-twist and Z-twist are alternately arranged every other steel cord as a tensile member.
Is shown.

FIG. 2 is a plate-like sheet 10b in which S-twist and Z-twist are alternately arranged every two steel cords as tensile members.
Is shown.

FIG. 3 is a plate-like sheet 10c showing a modification of FIG.

FIG. 4 is a cross-sectional view in the width direction of the rubber track of the present invention.

FIG. 5 is a longitudinal sectional view of the rubber track of the present invention.

[Explanation of symbols]

 1 ‥ S twisted steel cord, 2 ‥ Z twisted steel cord, 3,4 ‥ unvulcanized rubber sheet (cover rubber), 10a, 10b, 10c ‥ plate sheet, 10 ‥ rubber crawler, 11 ‥ core, 12 ‥ Rubber lug, 20mm endless joint.

Claims (4)

[Claims] 1. A rubber track in which steel cords extending in the longitudinal direction of an end rubber elastic body are buried in rows in the width direction, and steel cords projecting from both ends are overlapped to constitute a joint portion. A rubber crawler excellent in straightness, characterized in that the steel cord has a structure in which S-twisted cord groups and Z-twisted cord groups are alternately arranged in the width direction of the rubber crawler. 2. The rubber crawler according to claim 1, wherein said cord group is one or more. 3. An S-twisted steel cord group and a Z-twisted steel cord group are alternately arranged side by side to obtain a plate-like sheet covered with an unvulcanized rubber sheet from above and below, and a rubber crawler is formed from the plate-like sheet. After filling the unvulcanized rubber in the mold, press and heat to obtain a rubber elastic body with embedded steel cord, and overlap the steel cord protruding from both ends. A method for producing a rubber crawler excellent in straightness, characterized by filling an unvulcanized rubber into such a portion and applying pressure and heat to form an endless body. 4. The method according to claim 4, wherein each cord group is one or more.