JP2018024108A - Apparatus for manufacturing bead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a bead, which improves firmness of crimping of apex rubber to a bead core, and which prevents the rubber from being squeezed out and staying at a manufactured bead.SOLUTION: There is provided an apparatus for manufacturing a bead, which crimps apex rubber to a bead core. The apparatus includes: a V-shaped roller which has two disc-shaped rollers disposed in a V-shape, the two rollers sandwiching the apex rubber from both sides and pressing the apex rubber against the bead core, thus crimping the apex rubber to the bead core; and a pair of rollers which are disposed downstream of the V-shaped roller, and which press, from both sides, the apex rubber and the bead core having been crimped to each other. One of the pair of rollers is a columnar roller, and the other roller includes: a columnar small diameter portion; a columnar large diameter portion that is formed at an end opposite to the small diameter portion; and an intermediate portion that is formed between the small diameter portion and the large diameter portion, and of which a diameter decreases from the large diameter portion toward the small diameter portion so as to form a tapered shape.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bead manufacturing apparatus for manufacturing a bead by pressing an apex rubber to the outer peripheral surface of a bead core.

  A bead of a pneumatic tire is manufactured by pressing an apex rubber, which is a rubber sheet having a triangular cross section, onto an annular bead core made of steel wire (see, for example, Patent Documents 1 and 2).

  The manufactured bead is set at the end of a molding drum to which another rubber member T for tire is attached, as shown in FIG. By bending B, it is crimped to another rubber member T for tire. FIG. 3 is a cross-sectional view illustrating the tire molding process. However, when the pressure bonding between the apex rubber B and the bead core C in the previous process is weak, the bent apex rubber B may be peeled off from the bead core C as shown in FIG.

  In order to prevent peeling of the apex rubber B from the bead core C in such a molding process, a bead manufacturing apparatus as shown in FIGS. 4 and 5 is conventionally used in the bead manufacturing process. In this bead manufacturing apparatus, the bottom surface of the supplied apex rubber B having a triangular cross section is disposed so as to face the bead core C fitted to the outer periphery of the disc-shaped support member 34, and then the base of the apex rubber B is provided. The bead core C and the apex rubber B are pressure-bonded by pressing the portion against the bead core C with the V-shaped roller 31 interposed therebetween.

JP 2004-202960 A JP 2011-240601A

  However, even if the above-described bead manufacturing apparatus is used, it is not easy to manufacture the beads appropriately, and various problems may occur in the processes after the bead manufacturing process.

  Specifically, even if the bead manufacturing apparatus having the V-shaped roller described above is used, it cannot be said that the bead core and the apex rubber were sufficiently crimped, and the apex rubber was peeled off in the tire molding process. Difficult to prevent reliably.

  Further, as shown in FIG. 4, when the angle at which the V-shaped roller 31 sandwiches the apex rubber B is shifted, or when the apex rubber B having a thick root portion is used, the rubber at the base portion of the apex rubber B becomes the bead core C. In some cases, the protruding rubber B1 was formed.

  When such a bead on which the protruding rubber B1 is formed is used, the rubber flow near the side surface of the bead core is disturbed in the vulcanization step of vulcanizing the green tire after molding, and the vulcanization mold and the green tire There is a risk that scratches may occur in the vicinity of the bead portion of the tire after vulcanization due to the air remaining between.

  Then, this invention makes it a subject to provide the manufacturing apparatus of the bead which can be more firmly crimped | bonded a bead core and apex rubber, and a rubber | gum does not form in the bead after manufacture.

The invention described in claim 1
A bead manufacturing apparatus for manufacturing a bead of a pneumatic tire by pressure bonding a bead core and an apex rubber,
Two disk-shaped rollers are arranged in a V shape, and a V-shaped roller that presses the bead core by pressing the bead core sandwiching the conveyed apex rubber from both sides;
The apex rubber disposed on the downstream side of the V-shaped roller, and a pair of rollers that press the bead core from both sides;
Of the pair of rollers, one roller is a cylindrical roller,
The other roller is formed between a cylindrical small-diameter portion, a cylindrical large-diameter portion formed at an end opposite to the small-diameter portion, and the small-diameter portion and the large-diameter portion. A bead manufacturing apparatus comprising: an intermediate portion that is tapered in a tapered shape from a diameter portion toward the small diameter portion.

The invention described in claim 2
2. The bead manufacturing apparatus according to claim 1, wherein a width of the small diameter portion is 7.5 to 10 mm.

The invention according to claim 3
3. The bead manufacturing apparatus according to claim 1, wherein a taper angle of the intermediate portion is 3 to 5 ° with respect to a rotation axis of the other roller.

The invention according to claim 4
The bead manufacturing apparatus according to any one of claims 1 to 3, wherein the bead manufacturing apparatus is used for manufacturing a bead of a pneumatic tire having a tire size of 21 inches or less.

The invention described in claim 5
The bead manufacturing apparatus according to claim 4, wherein the pneumatic tire is a passenger tire or a light truck tire.

  ADVANTAGE OF THE INVENTION According to this invention, the bead core and apex rubber can be more firmly crimped | bonded, and the bead manufacturing apparatus which does not form a protrusion rubber in the bead after manufacture can be provided.

It is a side view which shows typically the whole structure of the bead manufacturing apparatus which concerns on one embodiment of this invention. It is a front view which shows typically the roller used for the manufacturing apparatus of the bead which concerns on one embodiment of this invention. It is sectional drawing explaining a tire shaping | molding process, (a) is the state which bent the apex rubber, (b) has shown the state from which the apex rubber was peeled from the bead core. It is sectional drawing explaining the manufacturing apparatus of the bead provided with the V-shaped roller. It is a perspective view explaining the manufacturing apparatus of the bead provided with the V-shaped roller.

  Hereinafter, the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a side view schematically showing an entire configuration of a bead manufacturing apparatus according to the present embodiment.

  As shown in FIG. 1, the bead manufacturing apparatus according to the present embodiment is disposed on the downstream side of the V-shaped roller 31 and the V-shaped roller 31 and presses the crimped apex rubber and the bead core from both sides. The rollers 12 and 13 are provided.

  The V-shaped roller 31 has the same configuration as the conventional one, and as shown in FIG. 4, two disk-shaped rollers 32 and 33 are arranged in a V-shape, and the apex rubber that has been conveyed Press B against the bead core C from both sides. Thereby, the apex rubber B can be pressure-bonded to the bead core C.

  A pair of rollers 12 and 13 having a shape as shown in FIG. FIG. 2 is a front view schematically showing a roller used in the bead manufacturing apparatus according to the present embodiment.

  The pair of rollers 12 and 13 squeeze the protruding rubber formed on the side surface of the bead core C by the V-shaped roller by sandwiching and pressing the apex rubber B and the bead core C pressed by the upstream V-shaped roller. The apex rubber B and the bead core C can be more firmly pressed together.

  Hereinafter, after the structure of the pair of rollers 12 and 13 is specifically described, the pressing of the apex rubber B and the bead core C by the rollers 12 and 13 will be described.

(1) Structure of Roller One of the pair of rollers 12 and 13 is a cylindrical roller having a rotation shaft 16, and one hypotenuse of the apex rubber B having a triangular cross section and one side of the bead core C. It is arranged so that it touches.

  The other roller 13 is formed between a cylindrical small-diameter portion 13c, a cylindrical large-diameter portion 13a formed at the end opposite to the small-diameter portion 13c, and the small-diameter portion 13c and the large-diameter portion 13a. The intermediate portion 13b is tapered from the large-diameter portion 13a toward the small-diameter portion 13c. 2 is a rotation shaft of the roller 13. The rotation shaft 17 is provided so as to penetrate the large diameter portion 13a, the intermediate portion 13b, and the small diameter portion 13c.

  And this roller 13 is arrange | positioned so that the small diameter part 13c may contact the other side surface of the bead core C, and the taper-shaped intermediate part 13b may contact the other inclined side of the apex rubber B.

(2) Pressing of bead core and apex rubber by a pair of rollers The pair of rollers 12 and 13 having the above-described structure is pressed between the apex rubber B and the bead core C after being pressure-bonded by the upstream V-shaped roller. To do. At this time, since the side surface of the bead core C is sandwiched between the cylindrical roller 12 and the small diameter portion 13c of the roller 13, the protruding rubber B1 (see FIG. 4) formed by the upstream V-shaped roller is crushed. Thus, the covering rubber B2 is formed on both side surfaces of the bead core C.

  Since the covering rubber B2 is formed flat, even if it is formed on the side surface of the bead core C, the vulcanized tire is not damaged like the conventional protruding rubber. And since this covering rubber B2 is formed so as to cover both side surfaces of the bead core C in a form continuous with the apex B, the apex rubber is peeled off when the apex rubber is bent in the tire molding process. Can be prevented.

  In addition, when the pair of rollers 12 and 13 press the apex rubber B and the bead core C between them, the pair of rollers 12 and 13 not only crush the protruding rubber on the side surface of the bead core C but also the apex rubber B which is pressed by a V-shaped roller. It can be pressed against the bead core C for further crimping.

  Specifically, as shown by the arrows in FIG. 2, when the rollers 12 and 13 press the apex rubber B and the bead core C, the tapered intermediate portion 13 b of the roller 13 turns the apex rubber B into the bead core C. Push in. Thereby, since the apex rubber B and the bead core C which have already been crimped by the upstream V-shaped roller can be further crimped, the apex rubber B and the bead core C can be more firmly crimped.

  As described above, according to the present embodiment, by arranging the pair of rollers having the shape shown in FIG. 2 on the downstream side of the V-shaped roller, the bead core and the apex rubber can be more firmly bonded to each other. It is possible to produce a bead that does not have protruding rubber. As a result, it is possible to sufficiently prevent the apex rubber from being peeled off in the tire molding process and to prevent generation of scratches near the bead portion in the vulcanization process.

  In addition, it is preferable that taper angle (theta) of the intermediate part 13b of the roller 13 is 3-5 degrees. When the taper angle θ is smaller than 3 °, the amount of the intermediate portion 13b pushing the apex rubber B toward the bead core C is reduced, so that the force when the bead core C and the apex rubber B are bonded is weakened. On the other hand, if the inclination angle θ is larger than 5 °, the amount of pushing by the taper-shaped intermediate portion 13b becomes too large and the shape of the apex rubber B changes, resulting in new scratches on the vulcanized tire. There is a fear.

  Moreover, it is preferable that the width W of the small diameter part 13c of the roller 13 is 7.5-10 mm. If the width W of the small diameter portion 13c is smaller than 7.5 mm, the protruding rubber on the side surface of the bead core C may not be sufficiently crushed. On the other hand, if it is larger than 10 mm, it becomes difficult to bring the tapered intermediate portion 13b into contact with the apex rubber B, and it becomes difficult to press the apex rubber B toward the bead core C for pressure bonding.

  Hereinafter, the present invention will be specifically described based on examples.

1. Example and Comparative Example (1) Comparative Example 240 beads were manufactured using a conventional bead manufacturing apparatus in which an apex rubber B was pressure-bonded to a bead core C using a V-shaped roller 31 as shown in FIG. The conditions are as follows.

Configuration of the bead core: After winding a single bead wire in 3 rows in 3 rows, 1 row winding in 4 rows Bead diameter: 1.2 mm
Apex rubber height: 50 mm

(2) Examples 1 to 8
As in the above-described embodiment, the bead is manufactured under the same conditions as in the comparative example, except that a bead manufacturing apparatus in which the rollers 12 and 13 having the shape shown in FIG. 2 are arranged on the downstream side of the V-shaped roller is used. Manufactured.

  In Examples 1 to 8, as shown in Table 1, the width W of the small diameter portion 13c of the roller 13 and the taper angle θ of the tapered intermediate portion 13b are changed.

2. Evaluation (1) Evaluation in Tire Molding Process A raw tire is molded using the manufactured bead, and the number of times the apex rubber B is peeled off as shown in FIG. The occurrence rate of peeling was calculated.

(2) Evaluation in the vulcanization process A raw tire molded using the bead after production is vulcanized and molded, and the tire after vulcanization is visually checked to obtain a scratch in the vicinity of the bead portion. The number was measured. For the tires in which scratches were generated, whether the scratches were due to abnormal apex rubber shapes or scratches from the protruding rubber was determined from the scratch state, and the rate of occurrence of each scratch was calculated.

3. Evaluation Results Table 1 shows the results of the evaluations described above for the comparative example and Examples 1 to 8.

  From Table 1, in the comparative example in which the apex rubber and the bead core are pressure-bonded only by the V-shaped roller, the pressure-bonding between the apex rubber and the bead core is weak, and the occurrence rate of the apex rubber during the molding of the tire is 1.50%. became. Furthermore, in the comparative example, there was a rubber that was formed on the side surface of the bead core after pressure bonding, and the rate of occurrence of scratches by this rubber was 5.00%.

  On the other hand, in Examples 1 to 8, both the occurrence rate of peeling of the apex rubber and the occurrence rate of the protruding rubber were lower than those in the comparative example. From this fact, by providing a roller having a shape as shown in FIG. 2 on the downstream side of the V-shaped roller, it is possible to produce a bead in which the protruding rubber is not formed and the bead core and the apex rubber are firmly pressure-bonded. It could be confirmed.

  And as a result of comparing the result of Example 1-Example 4 which made the taper angle the same value and varied the width | variety of a small diameter part, respectively, the width | variety of a small diameter part can be set in the range of 7.5-10 mm. It was confirmed that it was preferable.

  In addition, as a result of comparing the results of Examples 5 to 8 in which the width of the small diameter portion is the same value and the taper angles are different, it is preferable that the taper angle is set within a range of 3 to 5 °. It could be confirmed.

  Furthermore, among these, in Example 1 in which the width of the small diameter portion is set to 10 mm and the taper angle is set to 3.5 °, both of the peeling of the apex rubber, the scratch due to the abnormal apex rubber shape, and the scratch due to the protruding rubber are generated. However, it was confirmed that this was the most preferred embodiment.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

12, 13 Roller 13a Large diameter portion 13b Intermediate portion 13c Small diameter portion 16, 17 Rotating shaft 31 V-shaped roller 32, 33 Disc-shaped roller 34 Support member B Apex rubber B1 Extruded rubber B2 Cover rubber C Bead core T Tire rubber member W Width of small diameter part θ Taper angle

Claims (5)

A bead manufacturing apparatus for manufacturing a bead of a pneumatic tire by pressure bonding a bead core and an apex rubber,
Two disk-shaped rollers are arranged in a V shape, and a V-shaped roller that presses the bead core by pressing the bead core sandwiching the conveyed apex rubber from both sides;
The apex rubber disposed on the downstream side of the V-shaped roller, and a pair of rollers that press the bead core from both sides;
Of the pair of rollers, one roller is a cylindrical roller,
The other roller is formed between a cylindrical small-diameter portion, a cylindrical large-diameter portion formed at an end opposite to the small-diameter portion, and the small-diameter portion and the large-diameter portion. A bead manufacturing apparatus comprising: an intermediate portion that is tapered from a diameter portion toward the small diameter portion in a tapered shape.   The bead manufacturing apparatus according to claim 1, wherein a width of the small diameter portion is 7.5 to 10 mm.   3. The bead manufacturing apparatus according to claim 1, wherein a taper angle of the intermediate portion is 3 to 5 ° with respect to a rotation axis of the other roller.   The bead manufacturing apparatus according to any one of claims 1 to 3, wherein the bead manufacturing apparatus is used for manufacturing a bead of a pneumatic tire having a tire size of 21 inches or less.   The bead manufacturing apparatus according to claim 4, wherein the pneumatic tire is a passenger tire or a light truck tire.

Images