JPH02114074A - Caterpillar belt - Google Patents

Abstract

PURPOSE:To obtain the lightweight title device and realize cost cut and improve durability by forming a tensile strength core body whose upper and lower surfaces are covered by the reinforcing cloth and over rubber in succession, from a monofilament which has a flat section in nontwisting and has a specific ratio of width for thickness. CONSTITUTION:A truck belt installed onto a snowmobile, etc., i.e., a caterpillar belt is formed by covering the upper and lower surfaces of a tensile strength core body 10 by the upper and lower reinforcing cloth 11, 12 and a cover rubber 13 in succession. A lug rubber 15 is attached onto one side of the cover rubber 13. In this case, the tensile strength core body 10 has a flat section in nontwisting, and is formed from a monofilament cord 20 having the ratio of width W for thickness H is within a range of 2.0-4.0. Said monofilament cord 20 is arranged in the longitudinal direction. Therefore, the product can be made light-weight, and cost cut can be realized, and the antifatigueness and softness can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a track belt, that is, an endless track belt, which is attached to a snowmobile, etc. This invention relates to a track belt that reduces twisting costs by omitting the twisting process required for multifilaments, and has excellent bending fatigue resistance and flexibility.

[Conventional technology]

Conventionally, track belts are attached to snowmobiles, etc.
That is, as shown in FIG. 3, for example, as shown in FIG. 3, the structure of the track belt is such that a multifilament cord tensile strength core 1 having a circular cross section is arranged as a blind fabric in the longitudinal direction of the belt. Upper and lower reinforcing cloths are laminated on the upper and lower parts so as to sandwich 2°3, and are further covered with a cover rubber 4, and one side of the cover rubber 4 is provided with a lug rubber 5 that assists in driving the sprocket. ing.

As shown in FIGS. 3(a) and 3(b), the above-mentioned tensile strength core 1 is composed of first-twisted and first-twisted layers, similar to a tire cord, and has a structure in which the cross section is close to a perfect circle.

By the way, as a manufacturing method for the above-mentioned tensile strength core 1, after twisting a multifilament and forming it into a cord or fabric, a suitable adhesive treatment is performed.
Generally, it is bonded with rubber or resin.

[Problem that the invention seeks to solve]

However, when a multifilament having a circular cross section is twisted to form the tensile strength core 1, the following problems arise.

(1) Since fiber bundles with circular cross sections are assembled, the cord diameter becomes large. This causes the carcass layer to be thicker in gauge and the overall product to be larger in gauge and heavier.

(2) Since a twisting process is required, twisting processing costs are incurred. However, this processing is generally common to multifilaments, and is necessary to improve bending fatigue resistance, weaving processability, and adhesive processability.

(3) When the property of reducing elongation when used in a track belt is required, polyester fiber (polyethylene terephthalate) is provided as the core, but this fiber is susceptible to chemical deterioration at high temperatures; In particular, amine degradation is a typical example.

(4) Polyester fibers also have the disadvantage of poor fatigue resistance, resulting in a short product life.

(5) Since twist is added, the initial modulus decreases, and the elastic elongation of aliphatic polyamide fibers in particular increases.

As mentioned above, conventional twisting of multifilament fibers with a circular cross section has good bending fatigue resistance.

Although this method improves weaving processability and adhesion processability, it has various problems as described above.

[Purpose of the invention]

This invention was devised by focusing on such conventional problems, and reduces the gauge thickness of the carcass layer without impairing the initial modulus, strength, etc. originally possessed by the material.
In addition to reducing the weight of the product, we also aim to reduce costs by reducing the gauge of the carcass layer and omitting the processing of twisted yarn.
Furthermore, since the monofilament has a flat cross-sectional shape, it is an object of the present invention to provide a track belt with excellent fatigue resistance and flexibility.

Applications of this endless track belt include power transmission belts such as timing belts, trunk belts for snowmobiles, snowplows, etc.

(Means for Solving the Problems) In order to achieve the above object, the present invention covers the upper and lower parts of the tensile core with reinforcing cloth, and further covers the tensile core with a cover rubber. It has a non-twisted, substantially flat cross-sectional shape, and has a width (W) to thickness (H) ratio of 2.0 to 4.
．． The gist of the present invention is that it is composed of monofilament cords in the range of 0, and that the monofilament cords are arranged in the longitudinal direction.

[Action of the invention]

As described above, this invention has a tensile strength core having a non-twisted flat cross-sectional shape and a width (W) to thickness (H) ratio of 2.
．． By constructing the monofilament cord in the range of 0 to 4.0, it is possible to reduce the gauge thickness of the carcass layer without sacrificing initial modulus or strength, thereby reducing the weight of the product and reducing the gauge of the carcass layer. By omitting the twisting process, costs can be reduced, and since the cross-sectional shape of the monofilament is flat, a track belt with excellent fatigue resistance and flexibility can be obtained.

Figure 1 shows a non-twisted, substantially flat (elliptical) shape according to the present invention.
has a cross-sectional shape, and the ratio of width (W) to thickness (H) is 2.
．． A sectional view of a track belt for a snowmobile using a tensile strength core 10 made of a monofilament cord in the range of 0 to 4.0 is shown, and the tensile strength core 10 made of this monofilament cord is short in the belt thickness direction. The condition is that they are arranged so that they are long in the belt width direction.

The structure is similar to the structure of the conventional trunk belt, that is, the endless track belt shown in FIG. 11 and 12 are stacked to sandwich them, and are further covered with a cover rubber 13, and one side of the cover rubber 13 is provided with a lug rubber 15 that assists in driving the sprocket.

The monofilament cord having a flat cross-sectional shape used in this invention is a cord 20 consisting of one filament having an elliptical cross-sectional shape, as shown in FIG. The fiber cord 30a and FIG.
The fiber cord 30b is significantly different in shape from the conventional three-ply fiber cord 30b shown in FIG.

Here, the material of the monofilament cord is not particularly limited, but nylon 6, nylon 66, polyester, etc. are used, and nylon is preferable from the viewpoint of adhesion to rubber and bending fatigue resistance.

Further, the thickness of the monofilament cord is not particularly limited, but a range of 500 denier to 4000 denier is preferable in terms of bending hardness, durability, and weavability of the cord.

Furthermore, the monofilament cord must be used substantially untwisted. When twisting is applied, surface distortion occurs in the monofilament cord, resulting in a significant decrease in durability and strength.

Width (W) and thickness (H) of the monofilament cord
The ratio (W/H) is in the range of 2.0 to 4.0, preferably,
Range 7 from 2.5 to 3.5! ＋＜ Good.

If the above ratio (W/H) is less than 2.0, the thickness of the cord becomes too thick and the rubber layer in which the cord is embedded also becomes thick, which not only increases the weight of the track belt but also causes the sprocket to become too thick. For belts subjected to bending fatigue, the surface strain of the cords also increases, reducing the durability of the track strip.

On the other hand, if the ratio (W/H) is 4.0 or more, the width of the cord becomes wider and the number of cords that can be driven into a given width of light decreases, so the required strength may not be obtained or the required strength In order to obtain this, it is necessary to increase the number of laminated sheets, which significantly impedes productivity. Further, when the monofilament cord having a ratio (W/H) of 4° or more is used for the weft yarn, the rigidity of the endless track band in the lateral direction is reduced. Further, it is preferable that the monofilament cord has a strength of 7.0 g/d or more and an initial modulus of 45 g/d or more.

If the strength is less than 7.0 g/d, it is necessary to increase the number of cords inserted and the number of layers laminated, which is not preferable in terms of weight reduction and productivity.

Examples of this invention are shown below.

[Example 1] In the case of a polyhexamethylene adipamide monofilament with a near aspect ratio (W/H) of the width (W) and thickness (H) of the monofilament cord of 3°0, nylon,
A comparison of the properties with polyester and rayon multifilament cords is shown in Table 1 below.

(Left below) As shown in Table 1, monofilament dip cord is 45% thinner in gauge than 66 nylon multifilament, which is made of the same material, but is 22% stronger than polyester.

It is also advantageous when compared to rayon.

On the other hand, the initial modulus is also higher than that of 66 nylon multifilament, exceeding even the modulus of rayon and showing a value close to that of polyester.

Reducing the gauge of the tensile strength layer described above increases weight reduction and flexibility, and is advantageous for bending fatigue resistance.

On the other hand, the purpose of using a flat (elliptical) monofilament is to increase the initial modulus and strength of the multifilament cord, which decreases due to twisting. d or more, and the initial modulus is preferably 45 g/d or more.

2 and 4 above show the cross section of the flat monofilament according to the present invention and the cross section of the conventional multifilament, but the aspect ratio (W/H) is large (I see, the cord gauge is small However, on the other hand, the width (W) becomes large and the number of monofilaments cannot be placed at a constant interval, so an extremely large aspect ratio will not provide the desired strength. As mentioned above, this is actually disadvantageous.

Also, as the aspect ratio decreases, the cord gauge becomes larger and approaches a circle, making it thinner.

This is disadvantageous in terms of weight reduction and fatigue resistance.

Therefore, the aspect ratio (W/H) is 2.0 to 4.0,
Practically speaking, 2.5 to 3.5 is preferable.

Next, Table 2 shows examples in which the aspect ratio (W/H) is preferably 2.0 to 4.0.

In addition, the aspect ratio (W/H) of the 4000D 66 nylon seven filament is 3, 5.3.0, 4.5.
A trial weaving of a bamboo blind fabric using this as warp yarn was performed, and an adhesive treatment was performed to create a track belt as shown in Fig. 1, and a durability test was conducted.

At the same time, we also conducted a durability test on a conventional endless track belt (track belt) shown in Figure 3.

(Margin below) [Effects of the Invention] As described above, the present invention provides a tensile strength core having a non-twisted, substantially flat cross-sectional shape, and a width (W) to thickness (H) ratio of 2. Since it is composed of monofilament cords in the range of 0 to 4.0 and the monofilament cords are arranged in the longitudinal direction, the following excellent effects can be achieved.

(a) The gauge can be made thinner, and the weight of the endless track belt can be reduced.

(b) Unlike conventional multifilaments, a twisting process is not required, and costs can be reduced.

(C) The bending fatigue resistance is superior to that of polyester.

(d) 6 Unlike polyester, there is no fear of amine deterioration.

(e) An initial modulus equivalent to that of polyester is obtained.

(f) The cross section of the filament is approximately flat, so it is flexible.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a track belt implementing this invention, FIG. 2 is a sectional view of a monofilament implementing this invention,
Figure 3 is a cross-sectional view of a conventional endless track belt, Figure 4 (al,
(b) is a cross-sectional view of a conventional multifilament. 10... Tensile strength core, 11.12... Upper and lower reinforcing fabric,
13...Cover rubber, 20...Cord.

Claims (1)

[Claims] In an endless track belt in which the upper and lower parts of a tensile strength core are covered with reinforcing cloth and further covered with a cover rubber, the strength core has a non-twisted, substantially flat cross-sectional shape, and a width (W). A continuous track belt comprising monofilament cords having a thickness (H) ratio in the range of 200 to 4.0, and comprising monofilament cords arranged in the longitudinal direction.