JP2011126194A - Apparatus for manufacturing bead member for tire, method of manufacturing bead member for tire and bead member for tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the scorch of rubber by shortening an injection time of unvulcanized rubber upon the manufacturing of bead member for tire. <P>SOLUTION: The apparatus for manufacturing bead member for tire includes: a first molding mold 11 in which an annular bead core 14 is arranged; and a second molding mold 12 which is configured so as to form a cavity 18 for bead filler between the first molding mold 11 and the second molding mold 12 on the outside in the radial direction of the bead core 14 when being superimposed to the first molding mold 11 and is provided with a nozzle 26 which opened to the cavity 18 so as to permit injection of unvulcanized rubber for the bead filler into the cavity 18 and in which grooves extended along the flow path direction are formed on the inner wall surface. By disposing the grooves on an inner surface of the nozzle 26, passage resistance of the unvulcanized rubber on the grooves is made to be smaller than the passage resistance on the nozzle center part and, thereby, the occurrence of a turbulence flow that may cause the passage resistance in the nozzle 26 is suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a tire bead member manufacturing apparatus using injection molding, a tire bead member manufacturing method, and a tire bead member.

  A method of manufacturing an annular rubber member is disclosed which includes a step of extruding rubber through a die by an extruder and bonding the ends of the belt rubber together to form an annular shape (see Patent Document 1). .

  Moreover, the method of shape | molding the bead member which has a bead filler using an injection molding method is disclosed (refer patent document 2).

JP 2009-61691 A JP 2007-253470 A

  However, as in the conventional example according to Patent Document 1 described above, in the method of forming the bead filler for a tire by bonding the ends of the belt-shaped rubber together to form an annular shape, in the joint portion between the ends There has been a concern that the uniformity of the product tire, that is, the tire balance and uniformity, may deteriorate due to variations in gauges and stepped set position deviation. Further, when the gauge of the joint part is partially thickened, the vulcanization is delayed, so that it is necessary to extend the vulcanization time.

  Further, in order to solve such a problem, as in the conventional example according to Patent Document 2 described above, by using an injection molding method, a nozzle that is a flow path in the mold is passed through the mold cavity. A method of forming a bead member having a bead filler by injecting unvulcanized rubber has been proposed.

  However, the unvulcanized rubber for the bead filler has a high viscosity, and the adhesion with the inner wall (metal) of the nozzle in the injection temperature region (100 to 150 ° C.) increases. Therefore, when injecting unvulcanized rubber into the mold cavity through the nozzle, it is necessary to set the injection pressure high. Thereby, coupled with the rubber adhesion to the inner wall of the nozzle, the flow of the unvulcanized rubber in the nozzle becomes a turbulent flow, so that the passage resistance in the nozzle increases and the injection time tends to be longer.

  Next, unvulcanized rubber for bead filler has a high viscosity as described above, and the time required for vulcanization is short. Therefore, when the injection time becomes longer, the residence time of the unvulcanized rubber in the flow path of the mold also becomes longer, and the unvulcanized rubber is heated to a high temperature as described above. Before the injection of the unvulcanized rubber is completed, so-called rubber scoring occurs in which the vulcanization of the unvulcanized rubber proceeds.

  In view of the above facts, an object of the present invention is to shorten the injection time of unvulcanized rubber when manufacturing a bead member for a tire, and to suppress scorching of rubber.

  The invention according to claim 1 (the apparatus for manufacturing a bead member for a tire) includes a first mold on which an annular bead core is disposed, and the first mold on the radially outer side of the bead core when the first mold is overlaid on the first mold. A bead filler cavity is formed between the mold and the mold, and an unvulcanized rubber for the bead filler is opened into the cavity so that the bead filler can be injected along the flow path direction. And a second mold provided with a nozzle in which an extending groove is formed on the inner wall surface.

  In the tire bead member manufacturing apparatus according to claim 1, the inner wall surface of the nozzle provided in the second mold and opening in the cavity between the second mold and the first mold is provided along the flow path direction. And a passage resistance of the unvulcanized rubber in the groove is smaller than that of the nozzle central portion (non-groove portion). This suppresses the generation of turbulent flow, which is a cause of passage resistance in the nozzle, and therefore, when manufacturing a tire bead member, the time required to inject a predetermined amount of unvulcanized rubber into the cavity ( (Injection time) can be shortened. In addition, this makes it possible to prevent the vulcanization of the unvulcanized rubber from proceeding (rubber scorching) before the injection of the unvulcanized rubber into the cavity is completed.

  According to a second aspect of the present invention, in the tire bead member manufacturing apparatus according to the first aspect, the groove is provided on the entire circumference of the inner wall surface.

  In the tire bead member manufacturing apparatus according to claim 2, since the groove on the inner wall surface of the nozzle is provided on the entire circumference of the inner wall surface, generation of turbulent flow in the nozzle can be further suppressed. . For this reason, the injection | emission time of unvulcanized rubber can be shortened more and rubber scorch can be suppressed further.

  According to a third aspect of the present invention, in the tire bead member manufacturing apparatus according to the first or second aspect, the groove has a V shape or an arc shape in a radial cross section of the nozzle.

  In the tire bead member manufacturing apparatus according to claim 3, since the groove on the inner wall surface of the nozzle is V-shaped or arc-shaped in the radial cross section of the nozzle, the passage of unvulcanized rubber in the nozzle The injection time can be shortened by reducing the resistance.

  The invention according to claim 4 (method for manufacturing a bead member for a tire) is the method for manufacturing a bead member for a tire, wherein a second forming die is overlapped on a first forming die in which an annular bead core is arranged, and the outside of the bead core in the radial direction. And forming a bead filler cavity between the first mold and the second mold, and a groove formed in the second mold and extending along the flow path direction is formed on the inner wall surface. Injecting unvulcanized rubber for the bead filler into the cavity through a nozzle.

  In the method for manufacturing a bead member for a tire according to claim 4, unvulcanized rubber for bead filler is injected into the cavity through a nozzle in which a groove extending along the flow path direction is formed on the inner wall surface. The time required for injection can be shortened to suppress the scorching of rubber, and further the mixing of air into the bead filler can be suppressed.

  Invention of Claim 5 (Tire bead member) is manufactured using the manufacturing method of the tire bead member of Claim 4, and the said cyclic | annular bead filler is adhere | attached on the outer periphery of the said cyclic | annular bead core. .

  In the tire bead member according to claim 5, the tire bead member is manufactured using the method for manufacturing a tire bead member according to claim 4, and an annular bead filler is bonded to the outer periphery of the annular bead core. The bead filler has no seams or steps, and air is not mixed into the bead filler. For this reason, a high quality tire excellent in tire balance and uniformity can be obtained by manufacturing a tire using the tire bead member.

  As described above, according to the tire bead member manufacturing apparatus according to claim 1 of the present invention, the injection time of the unvulcanized rubber when the tire bead member is manufactured can be shortened, It is possible to obtain an excellent effect that it can be suppressed.

  According to the tire bead member manufacturing apparatus of the second aspect, it is possible to obtain an excellent effect that the injection time of the unvulcanized rubber can be further shortened and the rubber scoring can be further suppressed.

  According to the tire bead member manufacturing apparatus of the third aspect, it is possible to obtain an excellent effect that the injection time can be shortened by reducing the passage resistance of the unvulcanized rubber in the nozzle.

  According to the method for manufacturing a bead member for a tire according to claim 4, the time required for injection of the unvulcanized rubber into the cavity can be shortened, and rubber scoring can be suppressed. The excellent effect that mixing of air can be suppressed is obtained.

  According to the tire bead member of the fifth aspect, an excellent effect is obtained that a high-quality tire excellent in tire balance and uniformity can be obtained.

It is sectional drawing which shows the manufacturing apparatus of the bead member for tires. (A) It is a 2A-2A arrow expanded sectional view in FIG. 1 which shows the cross-sectional shape of a nozzle. (B) It is an expanded sectional view which shows the flow velocity distribution of the unvulcanized rubber in a nozzle. (A) It is a 3A-3A arrow expanded sectional view in FIG. 1 which shows the cross-sectional shape of a nozzle. (B) It is an expanded sectional view which shows the flow velocity distribution of the unvulcanized rubber in a nozzle. It is a perspective view which shows the bead member for tires. It is a 5-5 arrow expanded sectional view in FIG. 4 which shows the bead member for tires.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In FIG. 1, the tire bead member manufacturing apparatus 10 according to the present embodiment includes a first mold 11 and a second mold 12.

  The 1st shaping | molding die 11 is a type | mold by which the cyclic | annular bead core 14 is arrange | positioned, and the positioning surface (not shown) of the bead core 14 is provided in 11 A of mounting surfaces of this bead core 14, for example. Note that the positioning portion of the bead core 14 is configured as a plurality of convex portions arranged corresponding to the inner diameter of the bead core 14, for example.

  When the second mold 12 is stacked on the first mold 11, a cavity 18 for the bead filler 16 (FIGS. 4 and 5) is formed between the second mold 12 and the first mold 11 on the radially outer side of the bead core 14. It is configured to form. Specifically, on the side of the second mold 12 that faces the mounting surface 11A of the first molding die 11, a general surface 12A that comes into contact with the mounting surface 11A when the mold is closed is provided. For example, a concave portion 12B having a depth corresponding to the width of the bead core 14 and a diameter corresponding to the outer diameter of the bead filler 16 is formed in the central portion of the surface 12A.

  The recess 12B is formed, for example, in parallel with the general surface 12A and can hold the bead core 14 between the mounting surface 11A of the first mold 11 and the general surface 12A on the radially outer side of the bead core 14. And an inclined surface 12 </ b> D that forms a cavity 18 between the mounting surface 11 </ b> A of the first mold 11 and the bead core 14. Thereby, when the mold is closed, the shape of the cavity 18 is, for example, a substantially triangular shape in the cross section in the tire axial direction.

  The second mold 12 has a cavity 18 in which the unvulcanized rubber 20 for the bead filler 16 (FIGS. 2B, 3B, 4 and 5) can be injected. A nozzle 26 is provided in which an opening 18 is formed in the inner wall surface with a groove 24 extending along the flow path direction. The nozzles 26 are integrally formed in the second mold 12, and a plurality of nozzles 26 are formed in the circumferential direction of the bead core 14. Further, the nozzles 26 are respectively formed at the outlet portions of the flow path 22 for the unvulcanized rubber 20 from the supply port 12E provided on the upper surface 12U of the second mold 12 to the cavity 18, for example.

  The grooves 24 are provided, for example, uniformly arranged on the entire circumference of the inner wall surface of the nozzle 26, extend along the flow path direction in the nozzle 26, and have, for example, a V shape ( 2 (A)) or an arc shape (FIG. 3 (A)). Table 1 shows examples of dimensions of the groove 24 in FIGS. 2 (A) and 3 (A).

  The arrangement of the grooves 24 on the inner wall surface of the nozzle 26 is not limited to the illustrated example, and the grooves 24 may be provided intermittently in the circumferential direction of the inner wall surface of the nozzle 26.

  And the manufacturing method of the bead member for tires concerning this embodiment overlaps with the 1st shaping | molding die 11 in the radial direction outer side of the bead core 14, and the 2nd shaping | molding die 12 is piled up on the 1st shaping | molding die 11 which has arrange | positioned the cyclic | annular bead core 14. A step of forming a cavity 18 for the bead filler 16 between the second mold 12 and a nozzle 26 formed in the inner wall surface of a groove 24 formed in the second mold 12 and extending along the flow path direction, And a step of injecting unvulcanized rubber 20 for the bead filler 16 into the cavity 18.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. 1, in the tire bead member manufacturing apparatus 10 according to the present embodiment, a bead core 14 is placed at a predetermined position on the placement surface 11A of the first mold 11 and the second mold 12 is used as the first mold. 11 is piled up. Specifically, the mold is closed by bringing the general surface 12A of the second mold 12 into contact with the mounting surface 11A of the first mold 11 in an opposing state. Then, in a state where the first mold 11 and the second mold 12 are heated to, for example, 100 to 150 ° C., the supply port 12E provided on the upper surface 12U of the second mold 12 does not enter the flow path 22 in the direction of arrow A. Vulcanized rubber 20 is supplied. By injecting the unvulcanized rubber 20 into the cavity 18 from the nozzle 26 and filling the cavity 18, the tire bead member 28 in which the annular bead filler 16 is bonded to the outer periphery of the bead core 14 can be obtained. it can.

  At this time, as shown in FIGS. 2 and 3, the groove 24 extending along the flow path direction is formed on the inner wall surface of the nozzle 26, so that the passage resistance of the unvulcanized rubber 20 in the groove 24 is , Smaller than the nozzle central portion 25 (non-groove portion). In other words, the flow rate S1 of the unvulcanized rubber 20 in the groove 24 becomes larger than the flow rate S2 of the unvulcanized rubber 20 in the nozzle center portion 25.

  As a result, the generation of turbulent flow that is the cause of the passage resistance in the nozzle 26 is suppressed, so that a predetermined amount of unvulcanized rubber 20 is injected into the cavity 18 when the tire bead member 28 is manufactured. It is possible to shorten the time required for the injection (injection time). Further, this can suppress the progress of vulcanization of the unvulcanized rubber 20 (rubber scorch) before the injection of the unvulcanized rubber 20 into the cavity 18 is completed, and the bead filler 16. Mixing of air into the inside can be suppressed.

  Furthermore, the groove 24 on the inner wall surface of the nozzle 26 is provided on the entire circumference of the inner wall surface, and the groove 24 on the inner wall surface of the nozzle 26 is V-shaped in the radial cross section of the nozzle 26 (FIG. A)) or a circular arc shape (FIG. 3A), the generation of turbulent flow in the nozzle 26 can be further suppressed. For this reason, the injection time of the unvulcanized rubber 20 can be further shortened, and the rubber scoring can be further suppressed.

(Test example)
When an injection test was actually performed using the conventional grooveless nozzle and the nozzle according to the present embodiment, the time required to complete the injection of 220 cc of unvulcanized rubber through the nozzle was 92 seconds from the conventional time. It decreased dramatically to 26 seconds. In addition, since the injection time was shortened, the rate of rubber scoring in the bead filler was reduced from 81% to 0%. Furthermore, the flow rate of unvulcanized rubber in the nozzle has been improved, so that the incidence of air mixing into the bead filler has been reduced from 81% to 0%.

(Bead member for tire)
4 and 5, the tire bead member 28 is manufactured using the tire bead member manufacturing method and the tire bead member manufacturing apparatus 10 described above, and the annular bead filler 16 is semi-vulcanized. Thus, the annular bead filler 16 is bonded to the outer periphery of the annular bead core 14. Accordingly, the bead filler 16 has no seams or steps, and the injection time of the unvulcanized rubber 20 is shortened, so that no air is mixed into the bead filler 16. For this reason, by manufacturing a tire (not shown) using the tire bead member 28, a high-quality tire excellent in tire balance and uniformity can be obtained. The semi-vulcanized state means a state in which the degree of vulcanization is higher than that in the unvulcanized state but has not reached the degree of vulcanization required for the final product.

DESCRIPTION OF SYMBOLS 10 Manufacturing apparatus of tire bead member 11 1st shaping | molding die 12 2nd shaping | molding die 14 Bead core 16 Bead filler 18 Cavity 20 Unvulcanized rubber 24 Groove 26 Nozzle 28 Tire bead member

Claims (5)

A first mold in which an annular bead core is disposed;
When overlaid on the first mold, a bead filler cavity is formed between the bead core and the first mold on the radially outer side of the bead core, and the bead filler unfilled in the cavity. A second molding die provided with a nozzle that is opened in the cavity so that the vulcanized rubber can be injected and that has a groove formed in the inner wall surface extending along the flow path direction;
The manufacturing apparatus of the bead member for tires which has this.   The tire bead member manufacturing apparatus according to claim 1, wherein the groove is provided on the entire circumference of the inner wall surface.   3. The tire bead member manufacturing apparatus according to claim 1, wherein the groove has a V shape or an arc shape in a radial cross section of the nozzle. A step of stacking a second mold on a first mold on which an annular bead core is arranged, and forming a cavity for a bead filler between the first mold and the second mold on the radially outer side of the bead core. When,
Injecting unvulcanized rubber for the bead filler into the cavity through a nozzle formed in the inner wall surface with a groove formed in the second mold and extending along the flow path direction;
The manufacturing method of the bead member for tires which has this.   A tire bead member manufactured using the method for manufacturing a tire bead member according to claim 4, wherein the annular bead filler is bonded to an outer periphery of the annular bead core.

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