JPH10230706A - Tire for bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an open side type of tire for bicycle which has improved the anti-cutting performance and the anti-puncture performance. SOLUTION: 2 to 20 lines of monofilament threads of 20 to 100 denier which consist of a polyamide are paralleled or stranded to form a cord of 100 to 1000 denier, and such cords are woven to form a textile. Such the textile is used as tension members 4 used for a carcass layer 2, in an open side type of tire 1 for bicycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle tire, and more particularly, to a cut-off and puncture-resistant tire using a woven cloth made of a special cord for a tensile member forming a carcass part of the tire. Related to open-sided bicycle tires.

[0002]

2. Description of the Related Art In a bicycle tire, an open-side type tire in which a side portion of a carcass layer of a tire is exposed, the thickness of the tire, in particular, the thickness of the side portion is not reduced, thereby improving the tire. It is intended to secure cushions and reduce the weight of tires.

However, since there is no rubber layer for protecting the carcass layer in the side wall portion, the carcass layer is damaged when the bicycle comes into contact with a sharp object such as a stone or a nail while the bicycle is running. is there. In order to improve cut resistance and puncture resistance to such sharp objects, it is conceivable to use a carcass layer as a plurality of layers, but if the number of laminations is too large, the weight of the tire increases and the weight is reduced. Characteristic is lost. On the other hand, a single layer is not preferable because the cut resistance and puncture resistance become insufficient.

At present, a carcass layer having three side portions is generally used because it has cut resistance and puncture resistance to some extent and does not increase the weight too much. The type of bicycle tire is dominant.

A cord 14a used for a conventional tensile member 14 which is, for example, a woven fabric is made of a monofilament yarn 14c of about 2 to 10 denier as shown in the cross section in FIG.
0-200 corded or twisted cord 1
On the other hand, in the case of Japanese Utility Model Laid-Open No. 5-49406, the tensile member constituting the carcass layer is used as the outer layer of the three carcass layers of the side portion, while the flattened body 4a is connected with the connecting thread 14b. It has been proposed to improve cut resistance and puncture resistance using monofilaments without impairing weight reduction.

[0006]

However, the tire comprising the carcass part having the three-layer structure of the side part has a certain effect on the performance of both the weight reduction surface and the cut resistance and puncture resistance. Promising, in other words, compromised on both sides performance,
If the emphasis is placed on weight reduction, it can be said that further improvement is required, in that only insufficient cut resistance and puncture resistance can be obtained.

[0007] In addition, those using flat monofilaments, such as Japanese Utility Model Laid-Open No. 5-49406, are superior in cut resistance and puncture resistance as compared with a tensile body simply using a conventional multifilament yarn. And the effect of not impairing the weight reduction is recognized, but the use of a monofilament also results in a poor stretchability of the tensile body, which is the centering force (C.I.
F. ) Or rolling resistance (RR). There is also a problem in that the molding workability during tire manufacturing is deteriorated.

Therefore, the present invention does not impair the running performance of the tire and does not hinder the weight reduction.
An object of the present invention is to propose a bicycle tire that can have cut resistance and puncture resistance superior to conventional products.

[0009]

In order to achieve the above object, according to the present invention, there is provided an open-side type bicycle tire in which a carcass layer made of a tensile member having rubber adhered to a sidewall portion is exposed. In the above, as the tensile body used for the carcass layer, 20
It is characterized in that one to three monofilament cords having a denier of 100 to 1000 denier are drawn or woven using 2 to 20 monofilament yarns of 100 denier.

Therefore, a bicycle tire having more excellent cut resistance and puncture resistance in the side wall portion than that using a conventional multifilament can be obtained.

The filling rate of the yarn of the woven fabric used as the tensile member is 7
0% or more, so that the cut resistance and puncture resistance of the tire can be further improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of a bicycle tire according to the present invention will be described with reference to the drawings. FIG.
1 is a cross-sectional view schematically illustrating a bicycle tire according to the present invention.

The bicycle tire 1 is an open-side type tire and has a tread portion 3 in which tread rubber is laminated on the ground portion of the tire on the surface of the carcass layer 2.

The carcass layer 2 relating to shape retention and running performance of the tire has a structure in which a tensile member 4 made of a woven fabric is coated with a coating rubber (not shown) having good adhesiveness and low heat generation. The carcass layer 2 is folded outward at a portion corresponding to a tire bead, and a bead portion including bead wires 5 and 5 is formed at each of the folded portions. Both ends of the carcass layer 2 are extended to a portion corresponding to a tire ground portion, Both ends of the carcass layer 2 are overlapped at the tread portion 3 which is the tire contact portion, and the presence of the overlap portion reinforces the contact portion of the tire. In other words, the carcass layer 2 has two layers in the sidewall portion 6 of the tire, and the carcass layer 2 has three layers in the tread portion 3 which is the ground contact portion of the tire by overlapping the end portions of the carcass layer 2. .

A tread rubber is integrally laminated on a tread portion 3 which is a front side of a tensile member 4 made of a woven fabric forming a part of the carcass layer 2 having the above-described structure and is a ground contact portion of the tire. Natural rubber (NR), styrene-butadiene rubber (SBR),
A simple substance or a blend of nitrile rubber (NBR), butyl rubber (BR), chloroprene rubber (CR) and the like can be mentioned.

The bead wire 5 in the bead portion is formed of a usual metal wire or a rope made of organic and inorganic fibers such as aramid fiber, glass fiber, carbon fiber and the like. As the woven fabric for forming the tensile member 4 of the carcass layer 2, a weaving method that has been frequently used is used. For example, a sudare woven fabric in which a cord 4a which is a warp as shown in FIG. The yarn is composed of a Sudare woven fabric cut in parallel with the component yarn or a bias cut of a plain woven fabric, and the directionality of this filament yarn is in the range of 0 to 90 ° with respect to the tire circumferential direction. is there.

On the other hand, the filament yarn 4c constituting the woven fabric to be the tensile member 4 of the carcass layer 2 which is a feature of the present invention.
Uses a cord 4a in which 2 to 20 monofilament yarns of 20 to 100 denier made of polyamide are aligned or twisted to 100 to 1000 denier.

By using such a cord 4b, one filament is about 10 times thicker than the conventionally used multifilament yarn, and cut resistance and puncture resistance are improved. Even when used as a tensile member for the carcass layer 2, the stretchability is not inferior and the running performance of the tire is not hindered. Also, as described above, in order to improve cut resistance and puncture resistance, the thickness of the cord is not increased, so that the weight of the tire does not increase, and the weight reduction is the same as the conventional or cord. Although the improvement in cut resistance and puncture resistance is reduced by reducing the denier of the tire, it is also possible to make the tire lighter than before.

Here, the thickness of the monofilament yarn 4a is 2
If it is less than 0 denier, there is not much improvement in cut resistance and puncture resistance. If it exceeds 100 denier, the rigidity of the yarn becomes too large, making the tire manufacturing process difficult, and running performance of the tire. Is also not preferable because it has an adverse effect on

The number of the monofilament yarns 4a to be aligned or twisted is less than two or the cord 4
When the denier number of b is less than 100, the cord is too thin as a cord, so that even if the monofilament yarn is thickened, the cut resistance, puncture resistance and the like are generally weak, and the number of monofilament yarns is 20 or If the denier number of the cord exceeds 1000, the weight of the tire becomes too heavy and the running performance deteriorates, which is not preferable.

A specific example of a cord obtained by pulling out or twisting 2 to 20 monofilament yarns of 20 to 100 denier made of polyamide and twisting them to 100 to 1000 denier is 420 ^D / trade name of Unitika. 14 ^f -730, and the like. The cord can be used as a plain weave fabric, or the cord can be used as a warp and a weft made of a sudare woven fabric using cotton thread or human silk can be used as the tensile member 4. At that time, it is preferable that the filling rate of the yarn of the tensile member 4 be 70% or more in order to further improve the cut resistance and the puncture resistance of the tire. The coating rubber on the surface of the tensile member 4 has a thickness of 0.0
It is a very thin coating of about 5 to 0.2 mm. Examples of the rubber material include a simple substance such as natural rubber, styrene-butadiene rubber, and butadiene rubber, or a blend thereof, and are attached by a method such as gluing with a calendar. Things.

[0022]

EXAMPLES Next, in a bicycle tire (Example) embodying the present invention and a conventional bicycle tire (Comparative Examples 1 and 2) in which various changes were made in the configuration of the carcass portion of the tire, Comparative experiments were performed to determine the cut resistance (puncture resistance) and running performance of the tire.

In the embodiment, the tensile member constituting the carcass layer is:
A cord (manufactured by Unitika, trade name: 420 ^D / 14) having 14 denier monofilament yarns made of polyamide (6.6-nylon) having a thickness of 30 deniers.
^f ), the warp yarns are arranged in parallel in the range of density 130 ± 5 (lines / 5 cm), and the above-mentioned warp yarns are coarsely ligated with fine cotton yarns of number 40 in the range of density 5 ± 1 (lines / 5 cm). Woven cloth was used. Then, a rubber made of a blend of natural rubber and styrene-butadiene rubber is glued to the tensile body and coated to a thickness of about 0.40 mm to form a carcass layer, and tread rubber is laminated only on the ground contact portion of the tire. A side type bicycle tire was used. The tire diameter is 627 mmφ and the tire width is 23 mm.

In Comparative Example 1, a warp yarn composed of a cord of 420 deniers was prepared by aligning 84 5-denier polyamide monofilament yarns as the tensile member constituting the carcass layer described in the above embodiment. An open-sided bicycle tire under the same conditions as in the example was used except that a sudare woven fabric was used as the tensile member in the same manner as in Example 1.

In Comparative Example 2, one extra piece of a mosia woven fabric woven from polyamide (6-nylon) multifilament yarn was bias-cut outside the carcass layer of Comparative Example 1. An open-side type bicycle tire was used under the same conditions as in the example except that the cut resistance and the puncture resistance of the sidewall portion were improved by further increasing the carcass layer.

Comparative Example 3 is a flat yarn made of polyamide (6.6 nylon) having a carcass layer provided on the outer side of Comparative Example 2 and having a minor axis / major axis of 1/7. An open-sided bicycle tire was used under the same conditions as in the example, except that the fabric was a Sudare woven fabric woven under the trade name “HITEN”.

In each of the four bicycle tires having the above structure, in Test 1, the cut resistance and the puncture resistance at the tire sidewall portion and the tire center portion using an acute-angled blade and a piercing needle were further examined. In Example 2, the running performance of the cornering force (CF) and the rolling resistance (RR) was measured.

[Test 1] First, in an experiment of cut resistance and puncture resistance, a part of a machine frame constituting the experimental machine 21 was formed using an autograph AG-5000 manufactured by Shimadzu Corporation shown in FIG. The rubber base 2 is placed on the bottom frame 23 between a pair of columns 23, 23 rising from both ends of the bottom frame 22 to be formed.
A movable rod 25 is also disposed between the columns 23 and 23. The movable rod 25 is also supported by the columns at both ends and also serves as a weight that moves up and down while being guided. The downward acute-angled blade 27 is fixed via the.

First, the strength of the side portion of the tire is determined by sequentially placing the tire as a material sideways on a rubber base 24 and moving a moving rod 25 also serving as a weight at a speed of 50 mm / min. The force (load kgf) until the acute angle blade 27 in contact with the side portion of the tire penetrates the tire side portion is measured.

Next, the strength at the center of the tire is shown in FIG.
As shown in the figure, the rubber base 24 of all the experimental machines 21 is removed, and this portion holds the upright tire with the center portion (tread portion) of the tire positioned above, and supports 23 constituting the experimental machine 21. , 23 is disposed below the movable rod 25, and the movable rod 25 serving also as the weight is disposed.
An acute angle blade 27 is fixed via the holder 26 of the above, and the acute angle blade 27 and the piercing needle 29 are brought into contact with the center portion of the tire, and the strength (load kgf) until the acute angle blade 27 penetrates the tire center portion is increased. It was measured.

The results of experiments on the cut resistance and puncture resistance of each tire described above are shown in Table 1 below.

[0032]

[Table 1]

[Test 2] Regarding the following various tires,
In addition, its running performance was determined. In this performance test, a speed of 40 km /
Under a running condition of hr and a load of 40 kgf, a cornering force (CF) and a rolling resistance (RR) were measured. In this experiment, the camper angle of the cornering force (CF) was 20 ° and the slip angle was 2 °. The measurement results under the above various conditions are as described in Table 1 above.

In Table 1 above, as for the cut resistance, the larger the load value, the more excellent the durability. On the other hand, as for the running performance, the smaller the numerical value in the rolling resistance (RR), the better. Conversely, in the cornering force (CF), the larger the numerical value, the better the performance. According to the above experimental measurement results, the bicycle tire embodying the present invention (Example) has a tensile strength of the carcass layer of the tire of 420 monofilament yarns of 5 deniers, which is 420 pieces.
While maintaining approximately the same running performance as that of the tire of Comparative Example 1 using the denier cord, the cut resistance and the puncture resistance show an improvement of about 25 to 30%. Compared to tires, performance is greatly improved in cut resistance and puncture resistance.

Comparative Examples 2 and 3 are Examples and Comparative Example 1.
Although the structure is further arranged outside the carcass layer, the cut resistance and the puncture resistance are very excellent, but the running performance is inferior.
In particular, the rolling resistance performance of the embodiment and the comparative example 1
20 to 30% inferior to the above, and the weight is increased due to the provision of a new layer.

[0036]

In the present invention, a woven fabric is used as a cord having a tensile strength of the carcass layer of 2 to 20 monofilament yarns of 20 to 100 deniers, which are drawn or twisted to 100 to 1000 deniers. As a result, the single filament yarn has a thickness and strength several tens times that of a conventional multifilament yarn, so that a sharp resin has a large resistance as a single resin block. In response to this by exerting force, and in contrast to a multifilament woven fabric consisting of a bundle of thin fiber yarns, it is not separated by sharp objects like thin fiber yarns constituting multifilament yarns. Since the absolute amount of the filament yarn weave per unit area is small, the chance of penetrating this weave with sharp objects is naturally small. No longer, cut resistance of the tire, puncture resistance is ensured.

Further, by setting the filling rate of the yarn of the tensile member to 70% or more, the cut resistance and puncture resistance of the tire can be further improved.

According to the present invention, when the same denier number is used in the carcass layer of a bicycle tire by using the tensile member as described above, the weight is the same and the cut resistance and puncture resistance can be improved. By minimizing the improvement in cutability and puncture resistance or making it comparable to that of a conventional product, the tire carcass itself can be made thinner as a whole, which can lead to a reduction in the weight of the tire.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a bicycle tire of the present invention.

FIG. 2 is a cross-sectional perspective view of a main part of the tensile body in the case where a sudare woven fabric is used for the tensile body used in the present invention.

FIG. 3 is a schematic front view of a test machine for cutting resistance of a tire side portion.

FIG. 4 is a schematic front view of a test machine for cut resistance of a tire center portion.

FIG. 5 is a sectional view of a tensile member used for a conventional bicycle tire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bicycle tire 2 Carcass layer 3 Tread part 4 Tensile body 5 Bead wire 6 Side wall part

Claims (2)

[Claims] 1. An open-side type bicycle tire in which a carcass layer is exposed at a side wall portion, wherein as a tensile member constituting the carcass layer, 2 to 20 monofilament yarns of 20 to 100 denier made of polyamide are drawn. Align or twist to 100 ~
A bicycle tire using a cord made of a 1000 denier woven fabric. 2. The bicycle tire according to claim 1, wherein the filling rate of the yarn of the woven fabric used as the tensile member is 70% or more.