JPS6213201B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a pneumatic tire comprising a carcass ply containing a blind fabric as a reinforcing material, and more particularly to a pneumatic tire that eliminates the phenomenon of denting in the sidewall portion of the tire by specializing the structure of the blind fabric. Pneumatic tires are required to have excellent uniformity, without distortion or unevenness, in terms of appearance and performance. On the other hand, pneumatic tires generally use blind fabric in the carcass ply as a reinforcing material. The blind fabric is cut perpendicularly or obliquely to the longitudinal direction (so-called radial cut or bias cut), and the resulting individual sheet-like pieces are pasted together at the ends in the width direction (hereinafter referred to as selvedges). It is then cut into strips and used as carcass material. However, because this blind fabric is woven with a warp and a continuous weft, the weft regulates the warp at the blind selvage, resulting in a high warp density at the selvage, which causes the tire to be inflated during the tire manufacturing process. When inflating (inflating), the ear part does not stretch as much as other parts, so the sidewall part of the tire where the above-mentioned overlapping part of the ear part (hereinafter referred to as the splice part) is located is dented, and the other side adjacent to this dents. An uneven phenomenon occurs in which the wall portion swells, resulting in a decrease in the uniformity of the tire. Therefore, in order to prevent such a decrease in uniformity due to the use of blind fabrics, conventional methods have been proposed, such as making the overlapping portion of the selvage significantly smaller, or splicing without overlapping at all, the so-called butt splice method. but,
This method has the disadvantage that the splice portion tends to separate during tire molding or vulcanization and inflation. There is also a method to compensate for the dents by pasting rubber sheets on the splice parts after laminating them in the usual way, but this method has the disadvantage of significantly lowering productivity and increasing the weight of the tire. Furthermore, in the calendaring process,
Immediately before rubber coating, both ears are mechanically stretched to lower the warp density of the ears. However, the effect is temporary and will gradually recover and eventually disappear. In this case, the warp density of the blind selvedge portion is not resolved in subsequent steps and remains until the final tire product. Recently, in order to solve the above problem, a method of using high elongation weft yarns has been proposed (Japanese Patent Laid-Open No. 55-62235), but this method has a weak force for regulating the warp yarns in the selvedges. Therefore, even if the degree of high warp density is somewhat reduced, this tendency cannot be completely resolved. Generally, high elongation yarns are
Since undrawn yarn is used, heat resistance is extremely poor, and highly accurate temperature control is required when dipping the blind fabric into the treatment solution. Therefore, in order to improve heat resistance, composite fibers have been developed in which the outside of undrawn yarn is wrapped and coated with cotton yarn etc. for insulation, but the yarns obtained in this way are extremely expensive due to the manufacturing process. The disadvantage is that it requires The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and provides a pneumatic tire that does not cause the phenomenon of denting in the sidewall portion, although it uses blind fabric as a carcass material. The purpose is to Therefore, in the present invention, a sheet made of a blind fabric coated with rubber is cut perpendicularly or diagonally to the longitudinal direction, and the obtained sheet-like pieces are pasted together at the width direction ends of the sheet. In a pneumatic tire having a carcass ply, the weft at the edge of the blind fabric in the carcass ply is inserted over the entire length in the longitudinal direction of the blind fabric at a point within 15 mm inward from the outermost edge in the width direction of the blind fabric. The gist of this article is a pneumatic tire that is characterized by being cut. Hereinafter, the configuration of the present invention will be explained in detail based on the drawings. FIG. 1 is an explanatory diagram showing the internal structure of an example of the pneumatic tire of the present invention, in which a steel belt 2 (two layers) is laminated on a carcass 1 (two layers), and a tread rubber 3 is laminated on top of the steel belt 2 (two layers). has been done. In addition, 4
is a bead wire. As is clear from FIGS. 2A and 2B, which are enlarged cross-sectional views taken along the line A, there are splices 5 in the carcass 1, and these splices 5 are spaced at regular intervals in the tire circumferential direction. There are multiple occurrences. In addition, 6 indicates a carcass cord (blind warp). FIG. 3 is an explanatory view showing an example of a blind fabric used for the carcass 1 in the present invention, and the blind fabric 7 is knitted from warp threads 8 and weft threads 9. The fiber material constituting this blind fabric 7 is not particularly limited, such as polyester, polyamide, acrylic, rayon, etc., but preferably polyester and polyamide. In the blind fabric 7, within the carcass 1, the weft yarns at the blind edge portion are continuously cut over the entire length in the longitudinal direction at a point B within 15 mm inward from the outermost end in the width direction. Note that if the cut exceeds 15 mm, it will be difficult to effectively achieve the purpose of the present invention, as is clear from the examples below, so the cut point should be within 15 mm as described above. is necessary. In other words, the closer the weft cutting part is to the edge in the width direction of the blind fabric, the greater the effect of relaxing the warp density regulation at the end by the weft; This is because the degree of influence on the warp density reduction at the end portion is small, so even if the length exceeds 15 mm, the phenomenon of denting in the sidewall portion of the tire cannot be eliminated. In addition, when the blind fabric 7 is used for the carcass 1, adhesive application and dimensional stabilization treatment (hereinafter referred to as dipping) are performed to maintain the shape, as in the conventional method. Therefore, the above cut is
It is preferable to cut the weft yarns at the selvedge portions after dipping, as it is desirable to cut the weft yarns at the selvedge portions without disturbing the ends of the warp yarns and without affecting the weft yarns other than the cut portions. The cutting method and cutting process are not particularly limited. For example, in a blind fabric coated with a rubber sheet on only one side during the calendering process, the weft threads can be cut using a scalpel fixed on a roll. Cutting is possible without affecting other weft threads. In this way, in the present invention, by cutting the weft yarns at the blind selvage part of the blind fabric used as the carcass material, the warp threads are no longer restricted by the weft yarns at the selvage part, so that the warp density at the selvage part does not increase and the Butt splice part (width 2-10mm)
The warp yarn density in , too, does not increase very much. Therefore, the elongation of the splice portion is not inhibited during inflation during the tire manufacturing process, and unevenness of the sidewall portion is prevented after vulcanization. Examples are illustrated below. Example 1 1000d/2 polyester, number of twists 45s×45z/10
cm, the number of ends (the number of cords within 5 cm of blind width), the warp composition is 50 cords / 5 cm, and the weft composition is 30s cotton yarn, the number of ends (3 cords / 5 cm).
After adhesion treatment with a resorcinol-formalin-latex solution, heat setting was performed under the conditions described below. The thus obtained blind fabric was subjected to a calendering process in which the weft yarns of the blind edges were cut over the entire length in the longitudinal direction of the blind fabric. The cutting positions are shown in Table 1 below in terms of distance from the edge of the blind. In this way, the rubberized sheet is made by cutting the weft threads of the edges of blind fabric.
It was cut in the width direction at right angles to the longitudinal direction at intervals of 50 cm, and the ends in the width direction were pasted together with 5 mm overlap to produce a carcass material.

[Table] Using blinds A to G with 55/5 cm ends and a 2-ply configuration as the carcass material, the angle of the carcass cord to the tire equatorial plane is 90°, and the tread part reinforcing belt material is all steel cord 2-ply. Created 165SR13 radial tire for passenger cars. The air pressure of the obtained tire was 1.7Kg/
cm ² and a rim of 4.5J x 13, the unevenness of the tire sidewall was evaluated, and the results are shown in Table 2 below.
It was shown to. In Table 2, "O" indicates good, "△" indicates slightly good, and "x" indicates poor (the same applies hereinafter).

[Table] However, the unevenness evaluation was performed according to the following method. A 10mmφ metal roller was rotated in the tire sidewall part to go around the tire, and the degree of unevenness was evaluated using a differential transformer using a deflection method. Differences in unevenness of the sidewall portion were detected at intervals of 25 mm, and the value with the largest difference in unevenness over the entire circumference of the tire was taken as the unevenness value of the sidewall portion. This value was ranked as follows.

[Table] The numbers in Table 2 are the numbers out of 100 tires. Example 2 The blind fabric used in Example 1 was used, the number of ends was 55/5cm, 2 ply configuration, and the angle of the carcass cord to the tire equatorial plane was 33°, size B78-13.
Bias tires were produced and evaluated in the same manner as in Example 1, and the results are shown in Table 3 below.

[Table] Example 3 A blind fabric made of 840d/2 nylon, twist number 47s x 47z/10cm, warp composition of 51 ends/5cm, and 30s cotton yarn, weft composition of 3 ends/5cm, was coated with resorcinol. After adhesion treatment with a formalin-latex solution, heat setting was performed under the conditions described below. The blind fabric thus obtained was calendered to cut the weft yarns at the blind edges. The cutting positions are shown in Table 4 below in terms of distance from the edge of the blind. The rubberized sheet with the weft of the edges of the bamboo blind fabric cut in this way is cut in the width direction at right angles to the longitudinal direction at intervals of 50 cm, and the edges in the width direction are cut 5 mm apart from each other.
A carcass material was produced by overlapping and pasting each other.

[Table] Blinds H to N with 56 ends/5cm in a 2-ply configuration are used as carcass materials, and the angle of the carcass cord to the tire equatorial plane is 78°.The tread portion reinforcing belt material is all steel cord 2-ply arrangement.Size 165SR13 created a radial tire. Table 5 shows the results of evaluating the sidewall unevenness phenomenon in the same manner as in Example 1.

[Table] As is clear from Examples 1 to 3, tires using a blind fabric as a carcass material in which the blind edge weft is cut within 15 mm from the end of the edge are extremely excellent in sidewall unevenness evaluation. I understand that.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the internal structure of an example of the pneumatic tire of the present invention, FIG. 2A is an enlarged cross-sectional view taken along the line A of FIG. 1, and FIG. 2B is an explanatory diagram of the cross-section. FIG. 3 is an explanatory diagram showing an example of a blind fabric used in the present invention. 1...Carcass, 2...Steel belt, 3...
...Treaded rubber, 4...Bead wire, 5...Splice portion, 6...Carcass cord, 7...Blind fabric, 8...Warp, 9...Weft.

Claims (1)

[Claims] 1. A pneumatic insert having a carcass ply, which is obtained by cutting a sheet made of blind fabric coated with rubber perpendicularly or diagonally to the longitudinal direction, and pasting the obtained sheet-like pieces together at the widthwise ends of the sheet. In the tire, the weft yarns at the edges of the blind fabric in the carcass ply are cut over the entire longitudinal length of the blind fabric at a location within 15 mm inward from the most end in the width direction of the blind fabric. pneumatic tires.