JPS63287604A - Bicycle tire - Google Patents

Abstract

PURPOSE:To aim at reduction of a rolling resistance, a light weight, and improvement in durability in the tire in the oaption having a breaker by forming the breaker into a reed-screen shape with cords, wherein high strength fibers and extensible fibers are twisted together, and setting the angle of cords as same as a carcass cord angle. CONSTITUTION:A breaker 16 is formed into a reed-screen shape with cords 24, wherein there are twisted together high strength fibers such as a steel wire, a glass fiber or the like, and extensible fibers such as a nylon fiber, a rayon fiber or the like. And thereat, the cords 24 are set at the approximately same angle as a carcass cord angle and arranged between carcass layers. Therefore, this constitution makes it possible to reduce a rolling resistance, aim at a lightweight, and also prevent the bending fatigue damage of the breaker.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a bicycle tire having a breaker for preventing damage to the tire due to sharp fragments, punctures, etc.

<Prior Art> Conventionally, in order to prevent damage to bicycle tires due to sharp fragments, punctures, etc., breakers made of woven fabric or wire mesh have been provided between carcass layers or between carcass layers and treads. .

However, as shown in Figure 5, woven fabric breakers are made of woven fabric that is finely woven vertically and horizontally at approximately equal intervals. Depending on the characteristics of the metal, etc., the rigidity of the tire contact area tends to increase. As a result, the rolling resistance coefficient of the tire becomes large, so that the tire must be rowed with great force, resulting in the problem that comfortable running performance cannot be obtained.

Among these, a woven fabric breaker is preferred because it is lighter than a metal breaker, but the woven fabric is selected from elongated fibers such as nylon fibers and rayon fibers, or glass fibers. Since it is made of filament yarn made by twisting long fibers selected from among high-strength fibers such as aromatic polyamide fibers, it has the following problems. In other words, if the breaker is made of extensible filament yarn, it becomes a relatively flexible breaker, so the running properties of the bicycle are somewhat improved, but on the other hand, it cannot be cut by sharp objects and is not sufficiently effective as a breaker. is not obtained. In addition, filament yarns made of high-strength fibers are less prone to breakage, but are more prone to bending fatigue, breakage due to bending during use, and have higher rigidity than those made from extensible fibers. The rolling resistance coefficient increases, resulting in poor running performance and ride comfort.

(Problems to be Solved by the Invention) This invention solves the problems of conventional bicycle tires with breakers, namely: ① The rolling resistance coefficient is large and comfortable running performance cannot be obtained; ② The problem is that the breaker is made of metal. This solves the problem of the breaker being heavy in some cases, and the problem of 2) being prone to breakage due to bending fatigue when the breaker is made of a finely woven fabric made of high-strength fibers.

(Means for Solving the Problems) The present invention provides a bicycle tire comprising a pair of bead portions and a plurality of carcass layers, and having a breaker between the carcass layers or between the carcass layer and the tread, wherein the breaker is It consists of a twisted cord made of high-strength fibers selected from steel wire, glass fiber, aromatic polyamide fiber, etc. and extensible fibers selected from nylon fiber, rayon fiber, etc., and the angle of the cord is adjusted to the carcass. The cord angle is approximately the same as the cord angle.

The twisted cords are preferably made by twisting spun yarns of high-strength fibers (twisted yarns of short fibers) and spun yarns of extensible fibers, and the cords of the carcass layer are arranged in the circumferential direction of the tire. It is preferable to set it as 30-60 degrees with respect to it.

(Function) Compared to conventional woven fabrics that are woven at approximately equal intervals and finely woven, the weft cord spacing (
Since the weaving yarn spacing is large, the bicycle tire becomes flexible and has a low rolling resistance coefficient, resulting in good running performance.

In addition, because the weft cord spacing of the breaker is large, and because at least the extensible fibers of the fibers constituting the cord are naturally or synthetic fibers, the breaker is more effective than metallic ones. It becomes lightweight.

Furthermore, the breaker cord is made of extensible fibers and high-strength fibers,
Preferably, the breaker is composed of spun yarns of each fiber twisted together, so the breaker has both the flexibility of extensible fibers and the strength of high-strength fibers, making it resistant to damage caused by sharp objects or breakage due to bending fatigue. Less likely to occur.

(Example) The present invention will be explained below based on Examples.

FIG. 1 shows a bicycle tire 1 according to an embodiment of the present invention.
0 is a partially cutaway perspective view of FIG. This bicycle tire 10
is a pair of bead portions 12.12 and the bead portion 12.1.
a carcass layer 14.14.14 that surrounds the tire and is folded back at the bead portion 12.12, and a breaker 16 provided between the carcass layers 14.14 directly below the tire ground contact area;
It consists of a tread 18 provided on the tire ground contact portion on the carcass layer 14, and is of a so-called open side type with no tread from part of the shoulder to the side part.

The bead portion 12.12 is made of a cord such as bead wire or aromatic polyamide fiber, and this cord is used as a bead portion of an ordinary bicycle tire.

The carcass layer 14.14.14 has both ends overlapped directly under the tire ground contact area, and has three layers in the liquid part.

This carcass layer is made by covering the sudare with rubber, and the cord of the sudare is oriented at an angle of 30 to 60 degrees with respect to the circumferential direction of the tire.
That is.

The breaker 16 is made by twisting a cord 24 of high-strength fibers 20 and extensible fibers 22 shown in FIG. 2 into a sagging shape as shown in FIG. 3. The cord 24 is provided between the carcass layers 14, 14 so that the angle of the cord 24 is approximately the same as that of the carcass layer 14, 14, 14. The reason why the cord angle of the breaker 18 and the cord angle of the carcass layer are made substantially equal is that it is effective in lowering the rolling resistance coefficient of the tire. The high strength fiber 20 is
Steel wire, glass fiber, aromatic polyamide fiber (e.g. Kevlar manufactured by DuPont, Conex manufactured by Tijin)
Spun yarn (a yarn made by twisting short fibers) is particularly preferable. Further, the elongated fiber 22 is made of spun yarn selected from nylon fiber, rayon fiber, hemp, cotton, etc.

Note that the breaker 18 has a tread 20 and a carcass layer 14.
It may be provided in between.

The tread 20 constitutes the ground contact part of the tire, and is engraved with a tread pattern according to the purpose of the bicycle.

Figure 5 shows the structure of this invention, which uses a 160-end sagging breaker made of spun yarns (number 30) of nylon fibers as extensible uA fibers and aromatic polyamide fibers (Kevlar) as high-strength fibers. bicycle tires and
The rolling resistance coefficient of a conventional bicycle tire using a nylon fiber or Kevlar woven fabric as a breaker is shown for a cord angle of 50° in the carcass layer. In addition, in this invention, when the air pressure is 7 kgf/cut and the cord angle of the carcass layer is 50°, 0.0056
It showed a rolling resistance coefficient of 0.00632 at 8.90'.

(Effects of the Invention) The present invention provides a breaker made of cords made of twisted high-strength fibers and extensible fibers in a sagging shape, with the cord angle being approximately the same as the cord angle of the carcass layer, and between the carcass layers or between the carcass layers. Because it was installed between the tread and the tread, the following effects were obtained.

That is, the rolling resistance coefficient of the tire can be reduced, the tire can be made lightweight, the breaker is less likely to break, and the breaker is less likely to break due to bending fatigue.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a bicycle tire according to an embodiment of the present invention, Fig. 2 is a front view for explaining the cord of a pre-car used in this invention, and Fig. 3 is a breaker used in this invention. 4 is a plan view of a conventional woven fabric breaker, and FIG. 5 is a graph showing the rolling resistance coefficient. 14 Carcass layer, 1G breaker-118 tread, 20 High strength fiber, 22 Extensible fiber, 24
Code Patent Applicant: Donjo Gome Kogyo Co., Ltd. Figure 1 Figure 3 Figure 5

Claims (3)

[Claims] (1) Consisting of a pair of bead parts and multiple carcass layers,
In a bicycle tire having a breaker between the carcass layers or between the carcass layer and the tread, the breaker is made of high-strength fiber selected from steel wire, glass fiber, aromatic polyamide fiber, etc., nylon fiber, rayon fiber, etc. A bicycle tire characterized in that it has a sagging shape made of cords twisted with extensible fibers, and the cord angle is approximately the same as the cord angle of the carcass layer. (2) The bicycle tire according to claim 1, wherein the twisted cord is a twisted cord of spun yarns of high-strength fibers (twisted yarns of short fibers) and spun yarns of extensible fibers. (3) The bicycle tire according to claim 1 or 2, wherein the cord angle of the carcass layer is 30 to 60 degrees with respect to the tire circumferential direction.