JPS583850A - Forming of tire band - Google Patents

Abstract

PURPOSE:To obtain a tire band having scarcely unevenness in elongation and strength, by cutting the plycords composed of more than three plies which are laminated so as the jointing parts are displaced in a longitudinal direction, making a cut face to incline and jointing the cut faces endlessly. CONSTITUTION:A plycord 4 is jointed so as a direction of a warp cord 1a becomes a width direction P by changing 90 deg. a direction of many sheets of short pieces 3 obtained by cutting a rubberized cord into a predetermined length. Then, a plycord laminate 9 is obtained by pressing more than three sheets of said plycords with a feed roll 5 so as joints 4a of short pieces 3 are dispersed at a nearly equal interval in a longitudinal direction and the tip parts 4b are shifted stepwise in the same direction. Next, the cord 9 is carried to an arrow R direction by a conveyer belt 6 and when the tip part 4b of the lowest layer cord 4 reaches just under a photoelectric feeler 8, the conveyer 6 is stopped and after the cord 9 is cut along an inclined line S in parallel with a cut face 9a above the concave part 7, the cut face 9a is adhered by an adhesive to a cut face 9b of the opposite side.

Description

[Detailed description of the invention] This invention relates to a method of forming a tire band.

Radial tires for automobiles are made by laminating multiple ply cords to form an endless tire band, attaching bead wires to both edges of this tire band, and then expanding and deforming it into a toroidal shape.A belt and tread are attached to the outer surface of the tire band. Rubber, sidewalls, etc. are attached, and the product is then vulcanized and molded. As shown in Fig. 1, the above ply cord is made by covering both sides of a blind weave 1 woven by warp yarns 1a and weft yarns 1b with rubber M2, and having a length equal to the width of the tire band. The direction of the cut strips 8 is changed by 90 degrees so that the warp cord 1a is in the width direction (direction of arrow P) and the weft thread 1b is in the length direction (arrow Q). 1 to 8 warp cords 1 at the side end of the cut short piece 8.
The short piece 8 is overlapped and joined to the side end of the next cut short piece 8 using the overlap margin a to form a long piece. Then, the long, joined ply cord is wound around a drum with a band length of 1 m, cut to a length slightly longer than the circumference of the drum, overlapped in the same manner as above, and joined to form an endless shape. By twisting the ply cords, winding them together, joining them endlessly, and repeating this process, an earband made by laminating several layers of ply cords is formed.

In this case, the length of one cut piece 3 constituting the above ply cord (the length in the direction of arrow Q in FIG. 1) is the width of the blind 11lil, which is determined by the width of the loom for the blind weaving This width is shorter than the circumferential length of the drum of the band forming machine, and is usually less than V2 of the circumferential length. There are a total of three or more joints including the joint. However, at this joint, the cords are arranged densely compared to other parts, and as a result, the strength is high and the elongation is low, so if the joints of the ply cords of each layer are located on the same radius line, In addition, the strength and elongation of the carcass of the product tire become uneven, and the tire sidewall becomes uneven, resulting in a deterioration in the performance and appearance of the tire. Therefore, when stacking the upper layer braai hood on the lower layer ply cord, the upper layer ply cord is wound so that the ends are shifted in the circumferential direction so that the ends do not overlap with any joints of the lower layer ply cord. It is necessary to disperse the joints over a wide range, and the distance by which the joints are shifted must be at least 5 m.

However, the conventional tire band forming method described above is
After wrapping the first layer of ply cord around the drum of the band forming machine, the second and eighth layers of ply cord are sequentially laminated, so the first layer, second layer, and second layer Even if it is possible to shift the joints of adjacent layers like the third layer, when winding the eighth layer ply cord, the first
Since the position of the joint of the ply cords of the layers cannot be confirmed visually, it is extremely difficult to make the joint of the first layer and the joint of the third layer 5 or more apart. When more than one layer of ply cord is laminated, the performance and appearance of the tire deteriorate.

Note that when joining the ends of the ply cords of each layer to form an endless shape, butt joints are also used instead of the above-mentioned overlap joints, but in this case, the ends of the ply cords located on both sides of the joint part are Since the two warp cords la and la are not connected by the weft 1b, this joint part stretches more easily in the circumferential direction than other parts, which reduces the strength of the product tire 2) and increases the strength of the third layer. 7 When wrapping ply cord, it is not possible to visually check the joints of the first layer of ply cord, as in the case of lap joints described above, so it is inevitable that the joints will be concentrated on the same radius line. Ta.

This invention makes it possible to avoid concentration of ply cord joints when forming a tire band by laminating three or more ply hoods, thereby improving the performance and appearance of the product tire. It is something.

That is, this invention is made by cutting a rubberized hood into a predetermined length, changing the orientation of a large number of the cut pieces by 90 degrees, and joining them into a long piece so that the direction of the cord is in the width direction.
A laminated ply cord is formed by stacking and pasting two or more pieces of ply cord so that the joints of the cut strips are shifted by a predetermined length in the length direction, and then this laminated ply cord is cut to a predetermined tire band length. This method of forming a tire band is characterized by cutting the tire band so that the surface thereof is inclined, and then bonding the cut surfaces at both ends with an adhesive to form an endless shape.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, 4 is a long ply cord formed by overlapping and joining the side ends of the cut short pieces 8, 4a is a short piece joint,
5.5 is a pair of feed rollers that nip the ply cord 4 shown in -E and feed it in the direction of arrow R. In front of the feed roller 5.5 in the feeding direction, pulleys 6a and 6b are provided.
, 6c, 6d, 13e and 6f, an endless conveyor belt 6 is provided which is rotated in the direction of arrow R, and the upper surface conveying portion of the conveyor belt 6 has a portion between two pulleys 6b and 6d. The four parts 7 are formed by pushing down with the pulley 6C. A photoelectric twin 8 for detecting the tip of the seven life hoods 4 is provided above the conveyor belt 6 at a position a predetermined length of the tire band away from the recess 7.

In the above structure, eight ply cords 4.4.4 are each drawn from a stock roll (not shown), which is unwound with a middle wrapping fabric (not shown), and feed rollers 5.5 The plate-shaped laminated ply cord 9 is passed through the nip point and crimped by the feed roller 5.5.
or formed.

At this time, the eight braai cords 4.4.4 have respective short piece joining parts 4a, 4a, 4a distributed at approximately equal intervals in the length direction, and respective tip parts 4b, 41)%4.
'b are stacked so that they are staggered by a predetermined distance of 5a or more in the length direction, and the stepped tips are cut and removed along the inclined cutting surface 9a as shown in FIG. .

The laminated ply hood 9 sent out from the feed roller 5.5 is conveyed in the direction of arrow R by the conveyor belt 6, and its tip (the tip 4b of the lowermost ply cord 4) advances a predetermined length from the recess 7. When the conveyor belt 6 reaches directly below the photoelectric filler 8, the conveyor belt 6 is stopped, and the laminated ply cord 9 is cut above the four parts 7 along the inclined line S parallel to the cutting surface 9a at the tip. The separated laminated ply cord 9 has a cut surface 9a at the tip.
And the cut surface 9b on the opposite side is coated with a quick-drying adhesive, and the above cut surface 9a is formed on a band forming machine.

By joining 9b, it is formed under an endless tire pan. In addition, after joining on a joining work bench different from the band forming machine, it may be attached to the band forming machine.

As mentioned above, since the spacing between the short piece joints 4a, 4a, 4a of the three pieces of ply cord 4.4.4 is set in advance to be approximately equal, the laminated ply cord 9 was cut. At this time, in the laminated ply cord 9 that is separated in front of the four parts 7, the distance between the short piece joining Fr1i4a of the bristle cord 4 and the cut surface 9b can also be easily known for the bristle cord 4 of the intermediate layer. . If any of the short piece joints 4a is located within 5 cm from the cut surface 9b, cut the laminated ply cord 9 in the same slanted shape as above at a position of 5 cm or more in front of the joint 4a. The above-mentioned short piece joining part 4a is removed, and the subsequent laminated ply cord 9 is joined to the laminated ply cord 9, which has been slightly shortened compared to the predetermined length, with the above adhesive, and then cut to a predetermined length in the same manner as above. . Similarly, in the laminated ply cord 9 left behind the four parts 7 (on the feed roller side), the short piece joint 4a of any one of the eight ply hoods 4 is connected to the cut surface (the next If the short piece joint portion 4a is located within 5a from the tip of the short piece (the tip of the short piece), the short piece joint portion 4a is similarly cut and removed, and the subsequent laminated braai hood 9 is cut to a predetermined length in the same manner as described above.

The tire band obtained by cutting and joining the laminated ply cord 9 to a predetermined length as described above is determined by the distance between the short piece joints 4a of the braai cord 4 and the joint between the short piece joints 4a and the laminated braai hood 9. (cut surfaces 9a, 9b) are both larger than 51, and since the cut surfaces 9a and 9b of the laminated ply cord 9 are formed as inclined surfaces and are bonded with adhesive, the tire There is almost no uneven stretching when the band is stretched in the circumferential direction.

In the embodiments described above, the conveyor belt 6 can be replaced by other conveying devices, such as a roller conveyor. Also, other limit switches such as a mechanical contact feeler may be used instead of the photoelectric feeler 80. Furthermore, the number of stacked Blycords 4 may be four or more. Further, in the embodiment described above, the short piece joints 4a of the ply hood 4 are shifted forward in the feeding direction in the order of the lower layer, the middle n11 layer, and the upper layer, but they may be shifted backward in the opposite direction.

As explained above, the present invention forms a laminated ply cord by laminating eight or more pieces of braai cord so that the joints in the ply hood are shifted in the length direction, and the laminated ply cord is Although the tire band is formed by cutting the tire so that it is inclined and joining the cut surfaces endlessly with adhesive, it is possible to obtain a tire band with less unevenness in elongation and strength, improving the performance of the product tire. Improves appearance.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a rubberized cord, FIG. 2 is a side view of an example of an apparatus used to carry out the invention, and FIG. 3 is a sectional view of a laminated ply cord. 1: Blind weave, l (1: +-do, 1b = weft, 3: cut short piece, 4 nibry cord, 4a: short piece joint, 9: laminated braai hood, 9a, 9b: cut surface.

Claims (1)

[Scope of Claims] [1] A rubberized hood is cut to a predetermined length, and the orientation of a number of the cut pieces is changed by 90 degrees and joined into a long piece so that the direction of the cord is in the width direction. A laminated ply hood is formed by laminating eight or more ply hoods made of 8 or more pieces of ply hood such that the joints of the cut strips are shifted by a predetermined length in the length direction, and then this laminated ply cord is attached to a predetermined tire band. Cut it long and with the cut surface slanted,
A method for forming a tire band, which is characterized in that the cut surfaces at both ends are then bonded together with an adhesive to form an endless shape.