JPH03262787A - Rubber crawler - Google Patents

Abstract

PURPOSE:To drastically improve durability of a rubber crawler by burying bias cord lines over the entire body of steel cords buried in a rubber, except for both ends that are folded with each other, at a preset angle in the width direction of the crawler. CONSTITUTION:A rubber crawler Z has lugs 1 of triangular cross section, extended in the width direction of the crawler Z, on its outer circumferential surface, while projections 3 are formed on each lug 1 facing sprocket holes 2. Core bars 4 are buried in a rubber 6 and are laid in parallel to one another in the width direction of the crawler Z, while steel cords 5 are buried over the entire length in the longitudinal direction of the crawler Z, and the steel cords 5 are endlessly continued with their ends folded with each other. A bias cord lines 6 are buried in a zone B at an angle of 0-30 degrees in the width direction of the crawler Z, provided the location where the cords 5 are buried folded is defined as zone A, while the other location is zone B.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a rubber crawler, and particularly to a rubber crawler that aims to equalize strain between lugs.

(Prior Art) In recent years, rubber crawlers have been widely used in bulldozers and the like, and the advantages of being made of rubber are being demonstrated.

The structure of this rubber crawler is generally that metal cores are lined up side by side and embedded in a long rubber-like elastic body, and a tensile body such as a steel cord is placed in the longitudinal direction surrounding this core. It is embedded.

Then, in order to make this long rubber-like elastic body endless, this tensile body protruding from both ends is overlapped with the above-mentioned core metal inside, and the rubber-like elastic body is integrated here again. It is a crawler.

FIG. 5 is a partial conceptual diagram showing a state in which a conventional rubber crawler Z is rolled around a drive wheel (not shown).

In the figure, reference numeral 5 indicates a steel cord, whose tips are overlapped and embedded in the rubber R to make the long body endless. In the figure, 1 is a lug, and rubber crawler Z
The metal cores are arranged horizontally in the width direction of the metal cores, and generally protrude from the outer peripheral surface to form a pair with an embedded core metal (not shown).

Now, as can be seen from this figure, the zone (A) where the steel cord 5 embedded in the rubber R overlaps.
Unlike the other zone (B), the rigidity becomes significantly high.

For this reason, the strain (elongation of the surface of the rubber crawler where no lugs are formed) becomes significantly large, especially at the boundary between the A zone and the B zone, that is, between the lugs 1 and 1 (S) at the end of the B zone side. In some cases, the allowable strain rate exceeds the limit compared to that of other parts, and it has become necessary to suppress this to a level that does not reduce the repeated bending fatigue resistance.

(Purpose) The present invention was made to improve the above-mentioned drawbacks, and aims to make the occurrence of distortion in the rubber crawler as uniform as possible, thereby increasing the durability of the rubber crawler. It is something that

(Structure) The present invention has been made to achieve the above object, and its gist is a long rubber-like elastic material in which lugs are formed on the outer peripheral surface and steel cords are embedded as tensile members. In a rubber crawler made by overlapping the steel cords in rubber to form an endless rubber crawler, a rubber crawler with a diameter of 0 to 309 in the width direction of the crawler is placed parallel to the non-overlapping portion of the steel cords in the width direction of the crawler. A rubber crawler characterized in that a bias cord row is embedded at an angle, and preferably the bias cord row overlaps the tips of the overlapping steel cords by a maximum of about 150 mm. Specifically, the bias cord described above is a steel cord or an organic fiber cord, and the cord rows are stacked in one or more layers.

In the case of overlapping two layers, each layer is embedded so as to intersect with the width direction of the rubber track at a certain angle, for example, an angle of 10''.

As for the position where this bias cord string is embedded, it is generally desirable to embed it along the outer periphery of the steel cord serving as the tensile member, so as to cover the tip of the steel cord from the outer periphery.

More preferably, in addition to adopting the above-mentioned structure, the interval between the lugs connected to the ends of the overlapping steel cords is approximately 20 mm relative to the interval between the lugs formed on the rubber surfaces of the overlapping steel cords. Preferably 10m
The distance is widened up to m.

It has also become possible to reduce rigidity by widening the gap between the lugs formed on the outer periphery of the area where the tip of the steel cord and the bias cord row overlap.

(Function) Since the present invention adopts the above-mentioned structure, the rigidity of the A zone where the steel cords are overlapped and the other B zone are made closer to each other, and in particular, by adjusting the spacing between the lugs, the rigidity can be further improved. The rigidity is made uniform, and the durability of the rubber crawler as a whole is significantly improved.

(Specific Example) Example 1 FIG. 1 is a conceptual diagram of a rubber crawler Z to which the present invention is applied, showing a state where it is wound around a drive wheel (not shown). 2 is a plan view of the rubber crawler according to the embodiment shown in FIG. 1, viewed from the outer circumferential side.

In the figure, reference numeral 1 denotes a lug formed on the outer peripheral surface of the rubber crawler Z, which has a substantially triangular cross section and extends in the width direction of the rubber crawler Z.

A sprocket hole 2 to which driving force is applied is connected to the center of the rubber crawler Z in the longitudinal direction, and a lug 1
are arranged alternately with the sprocket holes 2.

3 in the figure is a protrusion formed on the lug 1 facing the sprocket hole 2 and extending in the longitudinal direction of the rubber crawler Z.

Core metals 4 shown by dotted lines are embedded in the rubber R so as to be lined up in strips in the width direction of the rubber crawler Z. This core bar 4 is embedded across the sprocket hole 2 described above, and serves to transmit driving force from a sprocket (not shown).

Generally, the core metal 4 and the lug 1 are arranged so as to overlap each other.

In the rubber crawler 2, the greater the traction force, the more a tensile member is required, and generally a steel cord 5 is embedded in the entire length of the rubber crawler Z in the longitudinal direction. Second
In the figure, the tensile members are indicated by a dashed line and a dashed double dotted line.

The steel cord 5, which is the tensile member, is generally made by twisting thin steel wires, and is embedded in the rubber R so that they are lined up side by side with the sprocket hole 2 in between, as in the country side.

This steel cord 5 is made to include the core metal 4 when forming the rubber crawler Z, so the lug 1 and the core metal 4
It is inserted so that it is sandwiched between.

Such a rubber crawler Z is usually molded into a long piece, and in order to make it even more endless, only this part is molded again with the tips of the steel cords 5 overlapped.

In the figure, this superimposed steel cord 5 spans three lugs 1.

In the figure, the area where the steel cords 5 are buried in an overlapping manner is called Zone A, and the other areas are called Zone B.

Now, as mentioned above, when winding around a sprocket (not shown), a particularly large strain will occur at the boundary between zone A and zone B, which have significantly different rigidities, and this strain will occur because the lugs of rubber crawler Z are formed. As mentioned above, it appears intensively on the surface of the rubber on the outer circumferential side where there is no surface area.

The present invention has been devised to improve this problem.

That is, the aim is to eliminate the difference in stiffness between the two zones by bringing the stiffness of the B zone closer to that of the A zone rather than lowering the stiffness in the A zone, and for this purpose, the bias cord row 6 is connected to the steel cord 5 in the B zone. It is embedded in the rubber R in parallel to this.

By doing this, the rigidity in the B zone increases and approaches that of the A zone considerably.

On the national side, steel cords 5 are embedded in the rubber crawler Z with approximately the same width as the core metal 4 embedded in the rubber R, separated into left and right sides in the longitudinal direction of the rubber crawler Z, and one side is a hollow steel cord. Steel bias cord row 6 to cover the width of 5
are separately placed on the left and right sides at an inclination angle of approximately 20° with respect to the width direction of the rubber crawler Z.

In this example, one layer of bias code string 6 is applied.

Further, the steel bias cord row 6 overlaps the tips of the overlapping steel cords 5, thereby ensuring product durability.

In the figure, 6 indicates a bias cord, of which the portion indicated by a thin line indicates the portion embedded in the rubber R.

FIG. 3 shows a partial side view of the rubber crawler 2 in this example, and characteristically describes the steel cord 5 and the bias cord 6. Although the symbols and the like are the same as described above, the spacing between the lugs 1 in this figure will be explained here.

As mentioned above, this causes a large difference in the strain, that is, the tensile force of the rubber R on the outer peripheral surface of the rubber crawler Z. Concentrate on S. Therefore, the narrower the width of the rubber surface S in the longitudinal direction, the greater the concentrated force, which may cause cracks to occur in the rubber R, resulting in an extreme decrease in durability.

For this purpose, it is particularly preferable to use the Aias cord 6 with rubber R.
Durability can be further improved by embedding the lug in the rubber R and widening the lug spacing at the S portion on the surface of the rubber R to reduce the strain rate.

That is, if the lug spacing in the A zone is a, then among the lug spacing in the B zone, the lug spacing C closest to the tips of the overlapping steel cords 5 is set at a limit of about 20 mm, preferably about 10 mm, - in advance. By spreading it out, the strain rate of the surface S of the rubber R can be made relatively small.

Embodiment 2 FIG. 4 is a plan view substantially similar to FIG. 2 described above, and the side surface is also substantially the same as FIG. 3.

In this embodiment, the bias cord 6 is embedded in the rubber R in two layers.

In this case, each layer is embedded at an angle of about 20'' in the opposite direction to the width direction of the rubber crawler Z in a crosswise manner.

In this example, the strain on the rubber surface between the lugs was measured using a rubber crawler with a width of 500 mm and a pitch of 146 mm.

A test was conducted by winding it around an idler with a diameter of 415 mm, but when using a conventional rubber crawler of the same shape with all lug intervals of 30 mm, there was a strain of 30% or more, especially on the S section of the outer peripheral surface of the rubber crawler. The rate was close to 40% in some cases.

On the other hand, in the rubber crawler having the structure shown in Example 2, the bias cord 6 is embedded in the rubber R, further covering the tip of the steel cord 5, and the lug interval of 8 parts on the outer peripheral surface of the rubber crawler is used. For those with 35mm,
The increase in strain rate remained at about 20%, proving that durability performance was dramatically improved.

(Effects) Because the present invention has the above-described configuration, its durability has been greatly improved, and it has become able to withstand hard use such as construction machinery.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a first embodiment of a rubber crawler to which the present invention is applied, FIG. 2 is a plan view of the rubber crawler of the embodiment shown in FIG. 1, viewed from the outer circumferential side, and FIG. FIG. 4 is a plan view similar to FIG. 2 of the second embodiment, and FIG. 5 is a partial conceptual diagram showing a conventional rubber crawler rolled up around a driving wheel. 1... Lug, 2... Sprocket hole, 4... Core metal, 5... Steel cord, 6... Bias cord, A... Range where steel cords overlap, B...
- Overlapping range of steel cord, S...Rubber crawler outer peripheral surface a, b, C...Lug spacing. Figure 1 Figure 3

Claims (4)

[Claims] (1) A long rubber-like elastic body in which a lug is formed on the outer peripheral surface and a steel cord is embedded as a tensile member,
In the endless rubber crawler made by overlapping these steel cords in rubber, a bias cord is attached to the non-overlapping part of the steel cords parallel to this at an angle within 0 to 30 degrees with respect to the width direction of the crawler. A rubber crawler characterized by having embedded rows of. (2) The rubber crawler according to claim 1, wherein the row of bias cords overlaps the tips of the superimposed steel cords to a maximum of about 150 mm. (3) The rubber crawler according to claim 1, wherein the bias cord is an organic fiber cord. (4) The interval between the lugs connected to the ends of the overlapping steel cords is wider than the interval between the lugs formed on the rubber surfaces of the overlapping steel cords by up to about 20 mm. rubber crawler.