JP3117208B2 - Endless structure of rubber track - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endless structure of a rubber crawler and relates to a rubber crawler mainly applied to high-speed traveling.

(Prior Art) In recent years, rubber crawlers have been widely used for construction and civil engineering work vehicles. However, in order to obtain an endless or endless structure, a long rubber crawler base is formed, and then both ends are overlapped. Endless molding.

That is, as shown in FIG. 1, tensile steel cords 1 are embedded in parallel in rubber C in a row C in a base B constituting a rubber crawler A in the longitudinal direction as shown in FIG. The base A is formed by vulcanizing the rubber at the center a, and both ends b and b are arranged in a straight line in the width direction of the rubber crawler, which is left unvulcanized. . Next, as shown in FIG. 2, both ends b, b of each of the rows C, C composed of the steel cords 1, 1 are overlapped in a straight line as a whole in the width direction of the rubber crawler. The rubber crawler A is completed by being vulcanized and filled with rubber and then made endless. In the figure,
Reference numeral 3 denotes a lug formed on the rubber track A on the ground contact side.

However, when the rubber crawler A having this structure is wound around the pulley portion and rotates, when used at high speed, the tensile load on the steel cord row C becomes larger than at low speed, and the rubber crawler at this endless portion There is a problem of peeling between the steel cord row 2 and the steel cord row C and buckling of the steel cord 1 itself constituting the steel cord row C.

In addition, before and after the overlapping portion of the steel cord row C, since the tips b, b are in a straight line as a whole in the width direction of the rubber crawler as a whole, a rapid change in rigidity occurs during running, and this repetition occurs. Therefore, there is a problem that the fatigue load on the steel cord 1 is large, and the steel cord 1 is cut off early.

In view of this point, the present inventor tried to divide the steel cord row C into a plurality of sections as shown in FIG.
In this case, the butt portion D does not change much in rigidity during traveling and the bend on the pulley becomes smooth. However, when the tensile force is large, the mutual length L of the butt portion D is not long enough. As a result, the code 1 is pulled out.

Therefore, it is necessary to make the length L of the butted portion D relatively long. However, this leads to disadvantages of workability in endless molding, which complicates work man-hours, increases work time, and increases efficiency. This will result in a decline.

(Purpose) The present invention relates to an endless structure of this kind of rubber track, and an object thereof is to provide an endless structure in which a structure of a butt portion of a steel cord is improved.

(Structure) The present invention employs the following structure to achieve the above object.

That is, the gist of the invention is to insert an endless tensile steel cord row in the longitudinal direction of a long rubber elastic body serving as a base of a rubber crawler, and form both ends of the steel cord row into an endless shape. In the endless structure of the rubber crawler, the butting portion of the steel cord row is divided into a zigzag shape as a whole toward the width of the rubber crawler. The present invention relates to an endless structure of a rubber crawler, wherein a cord row is arranged and formed.

Here, the second steel cord row may be the same as or different from the tensile steel cord row of the rubber track, and the second steel cord row may be in the longitudinal direction with the tensile steel cord row. Is preferably 45 degrees or more.

The second steel cord row is embedded in the rubber in order to impart a pull-out force (shearing force). Of course, the smaller the inclination angle α is, the better. But,
If the inclination angle α with respect to the longitudinal direction is not too large, the rigidity of the rubber crawler will be increased in combination with that of the steel cord row at the time of bending on the pulley, which will have a negative effect on the characteristics of the crawler. become.

Therefore, in consideration of both functions, it can be said that the inclination angle α is preferably 45 degrees or more.

In addition, the second steel cord row may be disposed on one side of the endless portion of the tensile steel cord row, but may be disposed on both sides in some cases.

Of course, it is not very preferable that these steel cords are in direct contact with each other. In general, a so-called rubber coated steel cord row in which a steel cord row is surrounded by a thin rubber film is used.

In some cases, rubber coated fibers may be interposed between the superposed steel cord rows in these endless portions, and the end of the second steel cord row is similarly similarly prevented from splashing. It is also possible to place rubber coated fibers.

It is preferable that the second steel cord row covers the whole butted portion of the tensile steel cord, but it may cover only a part thereof.

(Specific Example) Hereinafter, further description will be made with reference to the drawings.

In the present invention, as a first step, the tensile steel cord row C has an exploded structure shown in FIG. That is, the tensile steel cord row C is divided into five sections, each having a length L of 20.
This shows a state in which the ends of the steel cord rows C are shifted at a distance of cm and the ends D are butted at different positions in the circumferential direction of the rubber crawler. In a zigzag shape.

Next, as a second step, as shown in FIG. 4, a second steel cord row E, which is the same as the tensile steel cord row C, is disposed so as to cover the entire butted portion D.

The second steel cord row E is overlapped with the tensile steel cord row C at an angle of about 90 °.

FIG. 5 is a cross-sectional view of the main part of the rubber track A showing the relationship between the tensile steel cord row C and the second steel cord row E of the rubber track A shown in FIG.

FIG. 6 shows that the steel cord row C for tensile strength is a rubber crawler A.
(C ₁ , C ₂ ) is distributed to the left and right in the width direction, and shows the endless part embedded in the rubber 2, and the steel cord rows C ₁ , C _{2 on} the left and right are divided into three and zigzag. (D) to form an endless structure. In the figure,
Reference numeral 4 denotes a sprocket hole provided at the center of the rubber track A.

In this case, although not shown, the second steel cord rows E are naturally arranged on the left and right sides with respect to the mating portions.

As described above, this second steel cord row E is
It is generally arranged so as to cover the entire endless butt portion D. However, depending on the case, it may be arranged to protrude from the butt portion D and cover it, or may be arranged slightly shorter than the butt portion D. It is possible. These are determined in consideration of the usage conditions of the rubber track A.

Further, the abutting ends of the steel cord rows C can be slightly overlapped.

In FIG. 7, the butt portions D of the steel cord rows C are arranged with their positions shifted in the longitudinal direction, which contributes to homogenization of rigidity.

In Figure 8 and Figure 9 is across the butt portion D of the steel cord row C, and the second steel cord row E ₁ and E ₂ be those arranged embedded in the rubber on both sides, Fig. 7 FIG. 8 shows a case where the second steel cord E _1, which is on the inner peripheral surface side of the rubber crawler, is disposed slightly longer than the second steel cord E ₂ on the outer peripheral surface side of the rubber crawler, while FIG. is an example in which a little longer the second steel cord E ₂ of the outer peripheral surface side of the rubber track to the contrary.

The Figure 10 is a partial exploded view of the case, at right angles arranged steel cords second steel cord row for columns C E ₁ and E ₂ as described so far (E ₁ and E ₂ may be the same direction), but shows the case of arranging the inclination angle alpha ₁ and alpha ₂ as approximately 70 degrees in this example.

In the case where the second steel cord row has a certain inclination angle as described above, it is preferable that α ₁ = α ₂ without a phenomenon such as twisting of the rubber track.

(Test Example) Specimen 1 This Specimen 1 is a comparative example. As shown in FIG. 3, it is a rubber crawler having a thickness of 36 mm and a width of 90 mm with the same rubber material as used for a rubber crawler. Created a belt.
As the tensile steel cord 1, 15 cords of 1000 kg / cord were arranged, and three endless cords were divided into five cordless cords, each having a butt portion D having a length (L) of 200 mm.

Specimen 2 Specimen 2 forms the endless structure of the present invention. The endless portion of the specimen 1 shown in FIG. 3 corresponds to the second steel cord row as shown in FIG. E is arranged at right angles to one side of the tensile steel cord row C to form an endless structure. The length L of the butted portion is 200 mm as in the case of the specimen 1. Of course, the rubber quality, thickness, width, and the like are the same as those of the specimen 1.

Specimen 3 This specimen 3 also has the endless structure of the present invention. Although not shown, the specimen 2 has an endless structure in which second steel cord rows are arranged on both sides of the endless portion. Things.

In the tensile test, both ends of the belt were pulled right and left, and the strength was measured. The results are shown in Table 1.

As can be seen from these results, in the specimen 2 having the structure of the present invention, by using the second steel cord row, the tensile strength of the specimen 1 having the structure of the conventional rubber crawler was reduced. , 1800 kg in strength, 1.47 times that of the specimen 1, and 1.95 times in the same way for the specimen 3 having the structure of the present invention, and the effect is remarkably superior to the conventional rubber crawler. Was something.

When these results are considered in reverse, the use of the endless structure in the present invention makes it possible to shorten the length of the butted portion to be shifted, so that the workability is remarkably improved. .

(Effects) As described above, according to the present invention, the end of the steel cord row is shifted in the circumferential direction of the rubber crawler so that the steel cord row does not have a straight line in the width direction, and further, the second steel cord row is moved to the end. Since the shearing force is provided by arranging the mating portions, and the steel cord row bears the force against the pulling force of the cords, the length of shifting the butting portions can be relatively short, Not only is the workability improved, but also the reinforcement of the endless part is more complete.

[Brief description of the drawings]

1 and 2 are partially cutaway side views showing an endless structure of a rubber crawler according to a conventional method, FIG. 3 is a partially cutaway exploded plan view of a first stage of the endless structure of the present invention, FIG. FIG. 4 is a partially cutaway exploded plan view showing a second steel cord row arranged in a second stage of the present invention;
FIG. 5 is a sectional view of a main part showing the relationship between the tensile steel cord row and the second steel cord row of the rubber track having the endless structure of the present invention shown in FIG. 4, and FIG. FIG. 7 is a partially cutaway exploded plan view similar to FIG. 3 but showing a steel cord row divided into right and left in the width direction of a rubber crawler and embedded in rubber, and FIG. A partially cutaway exploded plan view showing the
8 and 9 are sectional views of a main part showing an example in which a second steel cord row is arranged on both sides of a tensile steel cord row, and FIG. 10 is a further alternative in which the second steel cord row is arranged. It is a partial exploded view showing an example. A ...... rubber crawler B ...... rubber crawler body C ...... tensile steel cord for column D ...... butted portions E, E _1, E ₂ ...... second steel cord row 1 ...... steel cord 2 ...... rubber 3 … Lug 4… Sprocket holes α ₁ , α ₂ … Inclination angle of the second steel cord row

Claims (1)

(57) [Claims] An endless tensile steel cord row is embedded in a longitudinal direction of a long rubber elastic body serving as a base of a rubber crawler, and both ends of the steel cord row are abutted to form an endless shape. In the endless structure of the rubber crawler, the butted portion of the steel cord row is divided and zigzag as a whole toward the width of the rubber crawler,
An endless structure for a rubber crawler, wherein a second steel cord row is arranged and formed at an angle of inclination with respect to the steel cord row at the butted portion.