JPS63154334A - Molding method for bead provided with filler - Google Patents

Abstract

PURPOSE:To constitute the title filler so that a difference in thickness or physical properties is not generated in the filler, by including a process arranging an unvulcanized rubber ring almost coaxially with a bead in the vicinity of the said bead, and a process deforming the rubber ring into a predetermined form by crushing the same and adhering the same to the bead with pressure. CONSTITUTION:A turn table 3 is turned by 90 degrees in the direction of an arrow A, and a bottom force 4 and bead 7 are moved up to an arrangement stage C. As a screw 12 of an extrusion machine 10 is rotating always, unvulcanized rubber G cast through a casting part 16 is extruded by a fixed quantity through dies 22, 23 and made into a cylindrical form. When the rubber arrives at the arrangement stage C, a rotary blade 24 revolves round the circumference of the said cylindrical rubber while the rotary blade 24 is being rotated and a ring rubber H is cut off from the cylindrical rubber. A bottom force 4 whereon the bead 7 and ring rubber H are mounted arrives at a deformation stage D. A top force 31 is lowered, the said ring rubber H is crushed by the top force 31 and deformed so as to become a predetermined form of a filler gradually. With this construction, a thick part is not generated.

Description

[Detailed description of the invention] The present invention relates to a method for forming beads with filler.

In general, when manufacturing pneumatic tires, it is necessary to place filler around the bead, but such filler is produced by wrapping a strip of filler with a predetermined cross-sectional shape extruded from an extruder. After taking it and once docking it, it is unwound and cut into a predetermined length and pasted on the tire forming drum so that it is arranged around the bead. However, when the filler is pasted on the tire forming drum in this manner, the cycle time of the forming drum increases, resulting in a problem that the tire manufacturing efficiency decreases. Moreover, both ends of the filler are pressed together on the tire forming drum.

Because of this, the wall thickness of the joint increases, causing disturbances in the surrounding cords and adversely affecting the uniformity of the product tire.

In order to solve these problems, it has been proposed to form a filled bead by combining a bead and a seamless filler outside the tire forming drum. After storing a bead in an injection mold, unvulcanized rubber is injected into a cavity provided around the bead through a plurality of small diameter injection ports, and the rubber is molded into a predetermined shape to serve as a filler. I'm trying to crimp it on.

〜1. However, in the method described above, rubber is injected into the cavity from a plurality of small diameter injection ports, so the inflow timing and inflow of rubber are different between the vicinity of the small diameter injection ports and the intermediate position between the small diameter injection ports. There is a problem in that the pressure and the like are different, resulting in differences in the thickness, physical properties, etc. of the filler between the vicinity of the injection port and the intermediate position therebetween.

3. This problem is caused by the process of arranging an unvulcanized rubber ring near the bead approximately coaxially with the bead, and the process of crushing and deforming the rubber ring into a predetermined shape and crimping it onto the bead. This problem can be solved by a method of molding beads with fillers that includes the following.

First, an unvulcanized rubber ring is placed near the bead approximately coaxially with the bead.Next, the rubber ring is crushed using, for example, a mold of a press machine to transform it into a predetermined shape, and is crimped onto the bead. let In this way, since the rubber ring is crushed and deformed, no thick parts are created in the filler, and the entire rubber ring can be deformed simultaneously and uniformly, so the thickness and physical properties can be adjusted. The same can be said for the circumferential position of .

1 cliff 1 Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1.2, l is a molding device for forming beads 2 with fillers, and this molding device 1 has a horizontal disc-shaped turntable 3, which is rotated vertically by a drive mechanism (not shown). It is intermittently rotated about the axis in the direction of arrow A. This turntable 3 is provided with four stages separated by 90 degrees along arrow A, namely, a supply stage B, a placement stage C, a deformation stage D, and an ejection stage E. Furthermore, four lower molds 4 are attached to the upper surface of the outer end in the radial direction of the turntable 3 and are spaced apart from each other by 90 degrees, and each lower mold 4 is a ring portion that is raised and lowered by an ejector mechanism (not shown). 5, and a cylindrical portion 8 that passes through the ring portion 5 and is fixed to the turntable 3. A bead 7 is provided on the radially outer side of the supply stage B.
A supply means 8 for supplying to the lower mold 4 located at is disposed. Reference numeral 11 denotes a frame installed on the outside in the radial direction of the arrangement stage C, and the extruder 10 is installed on this frame 11. The extruder 1O has a radially extending barrel 13, in which a feed chamber 14 is rotated by a drive motor 15 and has an injection port 18.
Maybe the sending room! A screw 12 is housed therein for sending out the unvulcanized rubber G injected into the interior of the housing 4 toward the placement stage C. Arrangement stage C provided at the tip of the barrel 13
A vertical passage 18 communicating with the feed chamber 14 is formed in the block portion 17 located directly above the feed chamber 14 . 19 is a cylinder attached to the upper end of the block part 17, and the tip of the piston rod 20 of this cylinder 19 is connected to the cylinder 19.
It is inserted into a pressure feeding chamber 21 communicating with @18. A pair of dies 22 and 23 heated to about 80 to 120°C are attached to the lower end of the block part 17, and these dies 22 and 23 are heated to about 80 to 120°C.
When the unvulcanized rubber G is extruded downward through 2.23, the unvulcanized rubber G becomes a seamless cylindrical shape. 24
is a rotary blade that revolves around the cylindrical unvulcanized rubber G while rotating on its axis, and the cylindrical unvulcanized rubber G is cut by this rotary blade 24 to become a seamless adhesive rubber H. Further, the deformation stage D is provided with an upper mold 31 that is raised and lowered by a press machine (not shown), and when the lower and upper molds 4.31 are closed, both of these molds 4, 3
A mold space 32 having a predetermined shape, that is, the same shape as the outer shape of the filler-equipped bead 2, is formed between the filler and filler beads 2. Furthermore, discharging means 3e is installed outside the discharging stage E in the radial direction to adsorb the filler-equipped bead 2 located on the discharging stage E using an electromagnet or a vacuum, take it out, and discharge it to the next process.

Next, the operation of one embodiment of the present invention will be explained.

In this molding apparatus 1, each stage B, C, D, H
Although each operation is performed at the same time, in order to avoid complication of explanation, the explanation will focus on one bead 7. First, the bead 7 is fed from the supply means 8 as shown in FIG. 2(a).
As shown in FIG. 4. Move the bead 7 to the placement stage C. Here, since the screw 12 of the extruder 10 is constantly rotating, the unvulcanized rubber G injected from the injection port 16 is supplied to the pressure feeding chamber 21 through the passage 1, while the piston rod of the cylinder 19 20 protrudes, and the unvulcanized rubber G in the pressure feeding chamber 21 is extruded by a certain amount through the die 22, 23 and becomes cylindrical. Then, when the lower mold 4 on which the bead 7 is placed reaches directly below the cylindrical rubber, that is, the placement stage C,
The rotary blade 24 revolves around the cylindrical rubber while rotating, and cuts off a ring rubber H of a predetermined width from the cylindrical rubber. As a result, a seamless ring rubber H is formed as shown in FIG. 2(b). , near bead 7, in this example bead 7
The turntable 3 is rotated by 80 degrees, and the lower metal part on which the bead 7 and the ring rubber H are placed falls onto the ring part 5 on the outside in the radial direction of the ring part 5, and is arranged substantially coaxially with the bead 7. Mold 4 reaches deformation stage D. Next, the press machine is operated and the upper mold 31 is lowered as shown in FIG. 2(c). When the molding surface of the upper mold 31 comes into contact with the ring rubber H, the ring rubber H is crushed by the upper mold 31 and gradually deforms into the specified filler shape, and the bead 7 Crimp around the outer periphery of the Since the filler is formed by deforming the seamless ring rubber H in this way, no thick portions will be formed. Next, as shown in FIG. 2(d), when the upper mold 31 is pressed against the lower mold 4 and both molds 4.31 are closed, this closed state is maintained for a predetermined time, and the filler Bead 2 is cooled. Next, the press machine is operated again to raise the upper mold 31. At this time, in order to ensure that the bead 2 with filler remains on the lower mold 4, the temperature of the lower mold 4 is made higher than the temperature of the upper mold 31 by about 10 degrees Celsius, and the temperature of the upper mold 31 is It is preferable to apply Teflon coating etc. to the surface.
Next, the turntable 3 is rotated 90 degrees in the direction of arrow A, and the lower mold 4 on which the filler-attached bead 2 is placed is transferred to the ejection stage E. Next, as shown in FIG. 2(e), After the ring part 5 is raised together with the filler bead 2 by the ejector mechanism, the filler bead 2 is taken out by the discharge means 38 and discharged to the next process. Next, after returning the ring portion 5 to the initial position, the turntable 3 is rotated 90 degrees and the lower mold 4 is moved to the supply stage B. The above is the work of molding the filler-attached bead 2 when focusing on one bead 7, but during work at each stage, work is also carried out at other stages. Therefore, the efficiency of the molding operation is dramatically improved compared to the conventional case where all stages are performed successively using one injection molding machine.

Furthermore, when a test tire was molded using a bead with filler manufactured by applying this invention and dissected at the green tire stage, no voids were found between the bead and the filler. Ta. On the other hand, in the comparative tires molded using the conventional overlap joint method, voids were found here and there between the beads and the filler. In addition, after the test and comparison tires were vulcanized, they were mounted on a uniformity machine and longitudinal force fluctuations were measured, and no peaks appeared in the test tires, but in the comparison tires. A peak caused by the thick interior appeared. In addition, the longitudinal force fluctuation is statistically Q, 5 to 1.0K.
It was improved by about g.

Incidentally, if a placement stage and a deformation stage for supplying other types of ring rubber are installed between the supply stage B and the placement stage C or between the placement stage C and the deformation stage D, it is possible to do so.

The rubber can be made of two types of rubber.

As explained above, according to the present invention, the physical properties, thickness, etc. of the filler can be made uniform at any position in the circumferential direction.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing one embodiment of the invention, and FIGS. 2(a) to 2(e) are sectional views illustrating the invention in detail. L...Molding device 2...Bead with filler 4...Lower mold 7...Bead 31...Upper mold H...Ring rubber patent applicant Brideston Co., Ltd. agent Patent attorney Ta 1 ) Toshio 4...Lower mold H...Ring rubber

Claims (1)

[Claims] It is characterized by including the steps of arranging an unvulcanized rubber ring near the bead substantially coaxially with the bead, and crushing the rubber ring to deform it into a predetermined shape and crimping it to the bead. How to form beads with filler.