JPH01254404A - Radial tire for car - Google Patents

Abstract

PURPOSE:To improve the uniformity of the winding force of a belt portion by simultaneously winding plural layers of strips composed of rubber coated cords spirally at a defined winding angle around a belt portion with the same belt end as a winding starting point, and forming a reinforcing layer. CONSTITUTION:Two or more layers of strips 3, 4 formed with a plurality of cords coated with rubber are simultaneously wound spirally around a belt portion 10 with the same one side belt end 5 as the winding starting point, to form a reinforcing layer. At this time, the winding angle is set in the range of 0.1 deg.-0.4 deg.. By this structure, the winding time can be reduced, improving the uniformity and distributing property of winding force while also improving uniformity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radial tire for a passenger car suitable for high-speed running, and particularly relates to an improvement in a reinforcing layer disposed around the outer periphery of a belt portion.

[Conventional technology]

Conventionally, this type of tire has been constructed such that one or more reinforcing layers, ie, a main 1194 layer, are disposed at least on both ends of the outer periphery of the belt in order to reinforce the belt.

That is, on the outer periphery of the belt part, there are strips 7 approximately equal to the belt width as shown in FIGS.
Several methods have been proposed and implemented. However, since there is an overlapping allowance 8 of two or three layers at the end of the winding,
The rigidity on the circumference of the tire was discontinuous and the tire had an uneven surface, which caused problems with tire vibration. Therefore, recently, as shown in FIG. 6 or FIG. 7, for example, a narrow strip 9 coated with rubber and at least one reinforcing cord is spirally wound around the outside of the belt portion 10 starting from one end of the belt. Methods have been proposed, such as winding the reinforcing layer continuously in a shape, or roughly folding it back from the other belt end and ending the winding at the first belt end to form the desired reinforcing layer (
JP 61-51979, JP 62-203803
@etc).

(Problem that the invention is trying to solve) However, this method requires a lot of winding time, which is unfavorable in terms of production efficiency.Also, if winding is done at high speed in order to shorten the winding time, there is an overlap margin between adjacent strips. , or a gap occurs, and vulcanization occurs with air trapped in that area.
It can also cause premature tire failure. In addition, in radial tires that have two or more reinforcing layers around the entire outer circumference of the belt,
Making the first winding force and the second winding force uniform is an addition to the structure, which is undesirable from the viewpoint of uniformity because it causes slight variations in the winding force of the belt portion.

(Means for solving the problem) As a result of various studies to solve the above problem, this invention (first
Bell (Invention) discloses a radial tire for passenger cars in which two or more reinforcing layers are arranged on all or a part of the outer periphery of the tire. A configuration is adopted in which two or more layers are wound spirally around substantially the same opening 4 with the end of the belt as the winding start end, and the winding angle α is in the range of 0.1° to 0.4°.

The reason why the winding angle α of the strip is set to 0.1° or more is because if it is less than 0.1°, twisting will occur during winding, which will cause problems in the process, and the maximum
The reason for this is that if the angle exceeds 0.4°, wrinkles may occur due to an increase in the strip width, air may be trapped, etc.
This is because it becomes virtually impossible to wrap it. In addition, the winding start end is the same belt end on one side for all two or more strips, which greatly shortens the winding time and particularly ensures uniformity of the winding force from the standpoint of improving uniformity. This is to do so. As shown in FIG. 8, suppose that the belt center part 11 is the winding start end, and the strips 12.13
If both sides are wound spirally in the direction away from the outside, and both ends are turned back and wound again towards the center side, as shown in Figure 9, some single-layer parts will appear around the beginning and end of the winding. Further, since the triangular area 14 is formed as a step at that part, air enters and the air cannot escape after vulcanization, leading to a risk of failure. Also, in order to make sure to eliminate this triangular area 14, a part of the belt center 1
If it is roughly wrapped around 1, three layers will be formed in some parts, creating a step and uneven tire thickness, causing failure due to localized heat generation in the tire tread, and also causing vibration. Unfavorable in this respect.

By the way, in manufacturing the tie puller according to the present invention, for example, as shown in FIGS. Alternatively, it is possible to adopt a method in which they are fixed to each other at regular intervals of, for example, about 100 mm in the circumferential direction and are wound almost simultaneously.

The second invention of the present application is characterized in that, in addition to the configuration of the above invention, a slip 1-slip in which a plurality of cords are roughly coated with rubber is wound in a manner intersecting with reinforcing cords in the outermost layer of the belt portion.
It is at the point where it is wrapped at an angle α.

That is, as shown in FIGS. 2 and 3, for example, when a narrow strip 3.4 is wound spirally, the winding angle α is determined by the width of the strip 3.4 and the outer diameter of the tire.
This winding angle α is an angle that intersects the reinforcing cord 6 of the outermost layer of the belt portion. Note that β is the belt angle.

Furthermore, the third aspect of the invention is characterized in that, in view of the fact that the invention requires a configuration in which two or more strips are tied together and wound from the same starting end, the belt is The number of ends of the strips constituting the upper layer other than the lower layer adjacent to the outermost layer is smaller than the number of ends of the strips constituting the adjacent reinforcing layer.

[Effect]

Therefore, according to the first invention, the winding time is significantly shortened, and there is no overlapping margin or gap between adjacent strips to trap air, which improves the productivity and durability of the tire. . Also, according to the second invention,
In addition to the first invention, the rigidity of the belt layer and the reinforcing layer is improved integrally as a metal body, and the generation of standing waves during high-speed running and the delay of their starting speed (critical speed) are achieved, thereby improving high-speed durability. Improvements will be made.

Furthermore, according to the third invention, a bridging effect is imparted to the upper reinforcing layer to improve adhesion and improve the durability of the tire.

(Example) A radial tie A7 for a passenger car with a tire size of 225,150 VR16 was manufactured, and the test results for high-speed durability, vibration, and molding efficiency are shown in Table 1.

In addition, in Example 1, the reinforcing layer was formed by spirally wrapping the entire circumference of the belt part at a winding angle α that does not intersect with the cord of the outermost layer of the belt, and in Example 2, the reinforcing layer was formed at a winding angle that intersects with the cord of the outermost layer of the belt. In Example 3, the reinforcing layer was wound spirally around the entire circumference of the belt at α, and in Example 2, the number of ends of the upper layer of the reinforcing layer was further reduced than that of the lower layer: b. In Comparative Example 1, a strip having the entire circumferential width of the belt part was wrapped around two hands (see Figures 4 and 5), and in Comparative Example 2, two strips were wrapped around each other with the central position of the belt part as the starting point for wrapping the strip. The strip is spirally wound toward each edge of the image, and the strip is folded back from the edge to the center, and the winding ends at the center of the belt (see Figures 8 and 9), for comparison. Example 3 has a configuration in which one strip is spirally wound from one end of the belt section to the other end, and is folded back from the other end so that a portion of the belt 1 ends at one end (see Fig. 7). reference).

(Leaving space below) Table 1 (Note) Nido (thin dynamic load is 470 kg, air pressure is 2.0 km cm cm2,
Conducted in accordance with JΔSo 607C.

*Durability drum test conditions Air pressure: 2.9 kg/cm2 Load: ETRTO standard However, the running time for each step is 10 minutes until failure occurs.

*Tire molding efficiency Comparative Example 3 was set as 100 and expressed as an index.

As is clear from Table 1, the tires of the examples are found to be better in terms of vibration and durability than the tires of the comparative examples. Furthermore, in terms of production efficiency,
This is extremely good compared to Comparative Example 3. In addition, durability can be increased by crossing the wrapping of the reinforcing layer around the belt cord, and even better results can be achieved by changing the number of ends between each strip and decreasing the number of ends for the strip on the tread side. It is recognized that

Furthermore, FIG. 10 shows the winding angle α and winding time for Example 1 and Comparative Example 3, using the standard winding time of one strip (width 1 mm, one cord) shown in FIG. The arrow indicates the relationship with time. It can be seen from the graph that the winding time of Example 1 is significantly shortened. Furthermore, if the winding angle was less than 0.1°, twisting would occur during winding, and if it exceeded 0.4°, winding could not be done in fact.

Although both of these embodiments have a structure in which two strips are wrapped around the entire circumference of the belt portion, it is also possible to adopt a structure in which the strips are wrapped in two layers only at both ends and one layer is formed in the middle portion.

〔Effect of the invention〕

As described above, this invention has a structure in which at least two strips constituting the reinforcing layer around the outer periphery of the belt are wound from one end almost simultaneously, so that the winding time can be shortened compared to the conventional method, and in addition, the winding force can be reduced. Uniformity and dispersibility are obtained, and the tire is good in terms of durability and imaging.
In addition, by taking advantage of this structure, it is possible to wind the strip at an angle that intersects the cord of the outermost layer of the belt part (in the case of 1 digit, furthermore, if a structure is adopted in which the number of ends of the upper reinforcing layer on the 1 to red side is reduced) Tire performance will be further improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a state in which a strip is wound in a tie-V according to an embodiment of the present invention, FIG. 2 is a conceptual diagram showing the direction in which the strip is wound, and FIG. A schematic diagram of a tire according to an embodiment; FIGS. 4 and 5 are schematic front and side views showing a state in which a conventional belt width strip is wound; FIGS. 6 and 7 show a state in which another conventional belt width strip is wound. Figure 8 is a conceptual diagram showing the winding direction when the winding start part is part of the belt center, Figure 9 is a schematic diagram after winding, Figure 10 is the winding direction. This is a graph showing the relationship between angle α and winding time. 3.4...Strip 5...Belt end 6...
・Reinforcement cord 10 on the outermost layer of the belt part...part of the bell 1

Claims (3)

[Claims] (1) In a radial tire for a passenger car in which two or more reinforcing layers are arranged on the entire or part of the outer periphery of the belt, the reinforcing layer is wrapped around the same belt end on one side with a strip of rubber-coated cords. A radial tire for a passenger car, characterized in that two or more layers are wound almost simultaneously around the outer periphery of a belt portion as a starting end, and the winding angle α is in the range of 0.1° to 0.4°. (2) The radial tire for a passenger car according to claim 1, wherein the strip is wound at a winding angle α that intersects the reinforcing cord of the outermost layer of the belt portion. (3) The number of ends of the strips constituting the upper layer of the reinforcing layer other than the lower layer adjacent to the outermost layer of the belt section is smaller than the number of ends of the strips constituting the lower layer. Radial tires for passenger cars.