JPS5844484B2 - Bead wire for pneumatic tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION PRIOR ART A flipper (hereinafter simply referred to as a flipper) of a bead wire for a pneumatic tire is known from the prior art.

) consists of a ring-shaped bead wire and a piece of tape-like rubberized cloth (hereinafter referred to as flipper cord).

) A bias cord was used to prevent wrinkles on the inner circumference that naturally occur when wrapping the product in one piece.

Although the length of the flipper cord used is the same across the gold mine, when it is wound around the bead wire, the circumference of one part of the bead filler is, for example, about 5 Qm/m longer than the inner circumference of the standard bead wire body. For this reason, a bias cord is used in which the thread pitch located on the inner peripheral surface and the thread pinch located on a part of the bead filler can be freely changed.

There are two types of bias cord: sudare-woven bias cord, which is often used for bias tires, and thick-woven bias cord, which is used for radial tires.In both cases, to obtain the bias cord, a rubber coating is applied to the raw material. The cord must be cut at a desired angle with respect to its length using a rear bias cutter, and the cut pieces must be successively joined together.

This bias cutter is a large piece of equipment aimed at mass production, and the cost of the equipment is high, making it impossible to obtain bias cords of uniform quality because the splicing work involves doubling the spliced pieces. This is not desirable from an economical or quality standpoint.Also, since it is a bias cord, the thread pitch could theoretically change freely when wrapped around rings with different circumferences, causing wrinkles. This problem should never occur, but in reality, the double part of the splicing of F41J,
Wrinkles may occur due to the rubberized condition, or because the paternity is thick and the pressure of the rollers cannot sufficiently act on the rubber between the threads.

The harmful effects of wrinkles are that the air trapped inside the wrinkles expands during tire vulcanization and impairs adhesion, and that concentrated loads tend to occur on overlapping yarns at the wrinkled areas.

Objects and Solution of the Invention By making it possible to use plain weave rubberized cloth as a frimper cord in a state where it is simply cut,
It is an object of the invention to make the flipper low cost.

Embodiment] An embodiment embodying the present invention will be described based on the drawings.

As shown in Fig. 3, a 13" bead wire body 5 (which may include a heat cover) with an inner diameter of 334 m/m, a width and a thickness of 7 m1 m, and a bead filler wrapped around the outer circumferential surface, is attached on both sides. An example of a bead wire flipper 1 having a filler 6 wound around its surface to a height of 12771/m will be described below.

The flipper cord used was a plain weave cloth in which 59 420 denier vinylon threads were woven, each having 50 strands in length and width, and rubber was coated on only one side in contact with the bead wire body 5 and bead filler 6. It is made into a gauge and has a length of 1055m/m (677I/m of this).
//771 is the wrap allowance at both ends.

) and has a width of 31.5 m/m and is shaped like a belt.

The area A to be covered by the flipper cord is approximately as follows.

(Does not include ramping.) Outer diameter of the part wrapped by the flipper cord.

334+(12X2)=358% A=(π, 3582/4−π, 3342/4)X2
+334. πX7=33433mi On the other hand, the area a of the flipper cord used in this example is a=(1055-6)X31.5'-;33044mm
Therefore, the shortfall in the cord used is A-a==33433-33044=389 mm.

As shown in Figs. 1 and 2, the flipper cord 2 used has a large number of slits 3 extending over 11j of 10% on the left and right sides, excluding 11.5% in the center of the 315% gold mine. - Provided at a pitch of 30 steps with an angle of inclination of 60 degrees to the length direction.

As a result, there are 35 slits in the total length of 1055%.

Then, the flipper 1 is placed so that the middle part in the width direction between the slits 3 is located on the inner circumferential surface of the bead wire main body 5.
integrally covers the inner peripheral surface and both side surfaces of the bead wire main body 5 and both sides of the end of the filler 6 on the bead wire main body 5 side.

1055% length flipper including 6% ramping
In order to wrap code 2 to a height of 12% from the inner diameter, the insufficient length at the outer diameter part is 358, 76% of π-1049ζ, but if it is equally short at the 35 slit parts, the length of the cord at each slit part is Gap 4 is 76/35 mm; 2.2%.

Furthermore, if the aforementioned shortfall in cord area of 389 mm is equally shortened by the 35 slit portions, the area of the portion without a cord at each slit portion will be 389735'-; 1 ] m, m''.

The depth of each slit is 10% from the middle ring of the cord, so if the length of the slit is e, then co530°=1 o/U-=Q, 866 Therefore, g-1
010,866'-; 11.5%.

The area of the part without a cord made with the length of the slit 115 and the circumferential length of the gap 22X is calculated - L approximately 11□2
This is the same as the area of the portion without a cord in each slit portion, 11 myA, which was calculated from the shortfall in the cord area.

The bead wire flipper 1 of Example was also able to obtain measured values that were approximately similar to the calculated values described above.

Although the first embodiment has been described, the pitch, length, and angle of the slits, as well as the position of the slit throats, are made symmetrical with respect to the center line between the ends of the slits, as shown in Figure 2. There is no problem even if the cord is offset in the length direction as shown in FIG. 1, and rubber bows may be applied to both sides of the cord.

Effects of the invention When using a bias cord as a flipper as in the past, the flipper cord is one with a width of 30%, but the price of the conventional fly bar cord, including the processing fee for bias cutting, is 10%. In the case of the plain weave cord in this example, a cord with a slightly wider width of 31.5% is used as described above, but since the bias cutting process is not required, the cord price is actually about 6.5%. Prices can be reduced by more than 30%.

In addition, conventional bias cords usually have a gauge (thickness after rubberization) of 0.8%; on the other hand, the flipper cord of the present invention is a plain weave woven with thin threads at a small thread pitch. As long as the strength is the same, it may be thinner, and for this reason, the gauge of the plain weave cord in the example is 0.4%.

It is easy to understand that in the flipper work in which the flipper cord is bent and pressed using a known roller, the thinner the cord gauge is, the better the close contact between the flipper cord, the bead wire body, and the bead filler.

When using a bias cord, the opening of the yarn becomes larger toward the outer circumference, but the thickness of the yarn does not change, and only the coating rubber between the yarns is left exposed. Suppression works only on thick threads.

Therefore, only a suppressing effect that is reduced in proportion to the difference in the thickness of the threads is exerted on the thin covering rubber portion between the threads, but in the case of the plain weave cord of the example, 59 fibers per <50% are applied as described above. It is a cord with densely woven threads arranged, and there is no thread opening on the outer diameter side, and the gauge is only 0.
Since it is four pieces, the pressing action by the roller with a smooth circumferential surface is sufficiently effective.

As is clear from the above explanation, the present invention
By making a slit in the middle ring portion of the bead wire body, the bead wire body and the filler can be covered with a flipper having a length that is approximately the same as the circumferential length of the inner peripheral surface of the bead wire body.

In other words, since the outer peripheral side of the bead wire body and the filler part are located on the outer diameter side of the tire, the circumference is naturally longer than the inner peripheral side of the bead wire body, and each The slit opens and can absorb differences between directors.

On the other hand, in order to achieve the same object, contrary to the present invention, a slit is inserted in the center portion of the flimbar in the width direction, and the opposing edges of the slit are overlapped.
It is also conceivable to configure the structure so as to absorb the shortened circumferential length of the inner circumferential surface of the bead wire body.

However, if this is done, a large concentrated stress will occur in the stepped part formed by polymerization during tire vulcanization, resulting in unfavorable quality results, or air pockets will occur in the polymerized part, causing damage to the bead wire and tire rubber. There are many problems such as problems with the adhesion between the bead wire and the fact that the actual circumference of the bead wire cannot be set accurately due to the formation of an overlapping step on the inner periphery of the bead wire. arise.

In the present invention, the above-mentioned effects can be enjoyed without such problems occurring.

The weight of the flipper cord of the bead wire in the example is 8.3 g, whereas the weight of the flipper cord using the sudare weave bias cord is 23.1 g, and the weight is 26.6 g when using the thick weave bias cord. In terms of weight, we were also able to reduce the weight by approximately 65%.

[Brief explanation of drawings]

1 and 2 are perspective views showing different aspects of the flipper cord of the present invention, and FIG. 3 is a perspective view of a bead wire using the flipper cord of the present invention. Flipper...1, Flipper cord...2, Slit...3, Bead wire body...5, Bead filler...6°

Claims (1)

[Scope of Claims] 1. In a bead wire consisting of a bead wire main body, a bead filler, and a flipper, a belt-shaped woven cord woven with thin threads with a small thread pinch is used as the frimper, and the cord A large number of slits extending in a direction intersecting the length direction of the cord are provided at regular intervals in the wet end part excluding the center part of the width, and the center part in the width direction of the flipper is on the inner peripheral surface of the bead wire body. 1. A bead wire for a pneumatic tire, characterized in that a flipper integrally covers an inner circumferential surface and both side surfaces of a bead wire main body and both sides of at least an end of a bead filler on the bead wire main body side with a flipper. 2. The bead wire for a pneumatic tire according to claim 1, wherein the slit is oblique with respect to the length direction of the cord. 3. The bead wire for a pneumatic tire according to claim 1 or 2, wherein the sled throat is symmetrical with respect to the center line between the rain ends. 4. The slit is offset in the length direction of the cord from the slit at the other mountain end.
Bead wire for pneumatic tires as described in section. 5. The bead wire for a pneumatic tire according to claim 1, wherein the plain weave cord is rubberized only on one side that contacts the main body of the bead wire and the bead filler. 6. The bead wire for a pneumatic tire according to claim 1, wherein the plain weave cord is made of warp and weft yarns of 420 denier. 7 The plain weave cord is woven with approximately 59 cords per 50 mm both vertically and horizontally.Claim 1 or 6
Bead wire for pneumatic tires as described in section.