JPS6028711Y2 - Vehicle tire cord - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a tire cord for reinforcing vehicle tires.

Generally, this type of tire cord is constructed by twisting together a plurality of extremely thin wires, and an essential requirement for this tire cord is that it has excellent fatigue resistance.

That is, this is because the tire cord may suffer fatigue failure due to repeated compression or tensile bending that the tire receives as the vehicle moves.

For this reason, the conventional tire cord has the structure shown in Figure 1.
X 0022+I
Z / S Te is twisted together, and the mouth is 7 x
3 X O, 175 + I X O, 15, 8, 5/ 10
/3.5mm, S/ z/ S, and Ha is 1 X1
8X0.22+I Xo, 1\10/3.5 throat, ]/S
It is.

As mentioned above, tire cords have generally been improved to have good fatigue resistance by combining various types of ultra-fine wires while maintaining a certain level of strength. As shown in Figure 2, a difference in the movement of the strands occurs due to a change in the tensile stress a (mainly on the outside) or compressive stress b (mainly on the inside) of the strand 1 due to the difference between the outside and inside of the bend. , the strands 1 rub against each other, causing fretting wear 2 (wear caused by the strands rubbing against each other) as shown in FIG.

The wear powder produced by this wear acts as an abrasive and accelerates fretting wear, causing localized wear and fatigue failure.

As described above, the conventional tire cord structure described above has a complicated twisting structure, so the manner in which stress is applied is also complicated, which has the disadvantage of being inferior in terms of fatigue resistance.Furthermore, it has the disadvantage of increasing production costs. be.

The present invention was made to eliminate the above-mentioned drawbacks, and provides a tire cord with excellent fatigue resistance.

There are two major causes of tire cord fatigue failure, one of which is the quality of the strands.
The other one is a twisted structure.

This difference in twist structure changes how stress (compression or tension) is applied to each strand and the influence it has on fretting wear between the strands.

The present invention is concerned with improving the latter cause of wear and tear.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in Figure 4, 6
A core strand 4 having a substantially triangular cross section is formed by twisting the actual strands 3 at equal pitches and in the same direction, and on the circumference of this core strand 4 there are 13 lines aligned with the above strands 3. A tire cord 6 is formed by twisting strands 5 made of steel wires having a diameter, and a wrapping wire 7 having the same or different diameter as the strands is wrapped around the outer periphery of the tire cord 6 as necessary. be.

Since the present invention has the above configuration, when the tire cord is bent as shown in Figure 2, the tire cord spreads in the horizontal direction perpendicular to the center of bending, as shown in Figure 5, and is placed in the outermost layer. The gap between the strands 5 is now wider than when it is normal.

This is because the cross-sectional shape of the core strand 4 of the present invention is approximately triangular, and the gap between it and the outermost layer is large.

Moreover, this can be considered to indicate that the outermost layer of strands has excellent flexibility.

For this reason, the compressive and tensile stress applied to the tire cord of the present invention during bending is slow, and the abrasion powder due to fretting wear is easily dispersed, so local wear progresses slowly and fatigue resistance is reduced. It is excellent and does not cause fatigue failure.

FIG. 6 shows the results of a fatigue test on a tire cord according to an embodiment of the present invention and a conventional tire cord.

The configuration of the tire cord used in the above test is as follows.

Tire cord of the present invention (Figure 6A) 6 +13x O, 22+1 x O, 15 Twisting pitch 6.3/10.0/3.5 Ordinary twisting direction S/Z/S Conventional tire cord ■ 4 X 4 Xo, 22+I Xo, 15 (6th
Figure B) Twisting pitch 9.5/9.5/3.5 Twisting direction S/Z/S ■ I X 18X O, 22 + I X O, 15 (Figure 6 C) Twisting pitch 10.0/3.5mm Twisting direction Z/S In the above embodiment of the present invention, a case is shown in which a wrapping wire is wound, but a tire cord without wrapping has the same effect, but wrapping causes flare, that is, the end of the tire cord. It is possible to prevent the parts from coming apart.

As is clear from FIG. 6, the tire cord A of the present invention
The tire cords can obtain fatigue values 2 to 5 times higher than those of conventional tire cords B and C.

As mentioned above, the tire cord of the present invention simplifies the twisting structure, reduces the compressive and tensile stress applied to the strands in the compression direction, and slows down fretting wear, thereby significantly improving fatigue resistance. Furthermore, since the twisting structure is simple, the number of twisting steps can be greatly reduced, and its practical value is great.

[Brief explanation of the drawing]

Figure 1 A, C and C are cross-sectional views showing a conventional tire cord, Figure 2 is an explanatory diagram showing the stress distribution when the tire cord is bent, and Figure 3 shows the state of wear of the conventional tire cord. 4 is a cross-sectional view showing the configuration of the tire cord of the present invention, FIG. 5 is a cross-sectional view showing the arrangement of the tire cord of the present invention in a bent state, and FIG. 6 is a cross-sectional view of the conventional tire cord and the present invention. Fig. 2 is a curve diagram showing the results of a tire cord fatigue test.

Claims (2)

[Scope of utility model registration request] (1) In a tire cord made by twisting together multiple steel wires having the same wire diameter, six strands are twisted together at equal pitches and in the same direction to form a core strand with a substantially triangular cross-sectional shape, A vehicle tire characterized in that an outer layer is formed by twisting 13 wires on the circumference of the core strand, and the gap between each side of the cross-sectional shape of the core strand and the outer layer is increased. code (2) For a vehicle according to claim 1 of the utility model registration claim, characterized in that a wrapping wire having a diameter that is the same as or different from the diameter of the wire forming the tire cord is wound around the outer periphery of the wire for the vehicle. tire cord