JP6701705B2 - Tire manufacturing method and manufacturing apparatus - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a tire manufacturing method and manufacturing apparatus capable of preventing defective molding during vulcanization.

  BACKGROUND ART Conventionally, a tire is manufactured by vulcanizing and molding a raw tire in a vulcanization mold having a tire molding surface. The vulcanization mold is divided into a plurality of molds in order to facilitate insertion and removal of green tires. By assembling this mold, a tire molding surface for vulcanizing and molding a green tire is formed. A boundary line between molds is formed on the tire molding surface.

JP2012-158064A

  When a plurality of molds are assembled at the time of inserting the raw tire into the vulcanization mold, a part of the outer surface of the raw tire facing the boundary line is apt to be so-called rubber bite that is sandwiched between the molds. The rubber sandwiched between the molds remains in the mold as burnt rubber even after the green tire is vulcanized and molded. Since the burnt rubber adheres to the tire to be vulcanized and molded next, there is a problem that molding failure is caused.

  The present invention has been devised in view of the above circumstances, and provides a tire manufacturing method and a manufacturing apparatus capable of preventing a rubber bite between molds and preventing defective molding during vulcanization. Is the main purpose.

  1st invention of this invention WHEREIN: By assembling a 1st mold and a 2nd mold, a raw tire is used with the vulcanization metal mold|die which the boundary line of the said 1st mold and the said 2nd mold appears on a tire molding surface. A method of manufacturing a tire including a vulcanization step of vulcanizing, wherein before inserting a raw tire into the vulcanization mold, a concave portion that forms a concave portion on a portion facing the boundary line on the outer surface of the raw tire It is characterized by including a forming step.

  In the tire manufacturing method according to the present invention, the first mold is a tread mold for molding a tread portion of the tire, and the second mold is a side mold for molding a sidewall portion of the tire. Is desirable.

  In the tire manufacturing method according to the present invention, it is preferable that the recess forming step includes a cutting step of cutting the outer surface of the green tire to form the recess.

  In the tire manufacturing method according to the present invention, it is preferable that the recess forming step includes a pressing step of forming the recess by pressing an outer surface of the green tire.

  In the tire manufacturing method according to the present invention, it is preferable that the pressing step be performed by pressing a rotatable roller against the outer surface of the raw tire.

  In the tire manufacturing method according to the present invention, it is preferable that the roller is heated.

  2nd invention of this invention WHEREIN: By assembling a 1st mold and a 2nd mold, a raw tire is used with the vulcanization metal mold|die which the boundary line of the said 1st mold and the said 2nd mold appears on a tire molding surface. A tire manufacturing apparatus including a vulcanizing device for vulcanizing, characterized by including a recess forming device that forms a recess in a portion of the outer surface of the green tire facing the boundary line.

  In the tire manufacturing apparatus according to the present invention, the first mold is a tread mold for molding a tread portion of the tire, and the second mold is a side mold for molding a sidewall portion of the tire. Is desirable.

  In the tire manufacturing apparatus according to the present invention, it is preferable that the recess forming device includes a pressing device that forms the recess by pressing an outer surface of the green tire.

  In the tire manufacturing apparatus according to the present invention, it is preferable that the pressing device includes a pressing unit that is pressed against the outer surface of the raw tire.

  In the tire manufacturing apparatus according to the present invention, it is desirable to include a heating unit that heats the pressing unit.

  In the tire manufacturing apparatus according to the present invention, it is preferable that the pressing device includes a vibrating unit that vibrates the pressing unit.

  In the tire manufacturing apparatus according to the present invention, it is preferable that the vibrating means vibrates the pressing means so as to include a vibration component in the axial direction of the raw tire.

  In the tire manufacturing apparatus according to the present invention, it is preferable that the vibrating means vibrates the pressing means at a frequency of 5 Hz or higher.

  In the tire manufacturing apparatus according to the present invention, it is preferable that the pressing unit is a rotatable roller.

  The tire manufacturing method according to the first aspect of the present invention is a vulcanization mold in which the boundary line between the first mold and the second mold appears on the tire molding surface by assembling the first mold and the second mold. It includes a vulcanization process for vulcanizing green tires.

  The manufacturing method includes a recess forming step of forming a recess on a portion of the outer surface of the raw tire facing the boundary line before the raw tire is inserted into the vulcanization mold. With such a recess, the raw tire and the boundary line can be arranged apart from each other when the raw tire is inserted into the vulcanization mold. As a result, it is possible to prevent the rubber from being caught between the first mold and the second mold, so that it is possible to prevent molding defects during vulcanization.

  The tire manufacturing apparatus of the second invention of the present invention is a vulcanization mold in which the boundary line between the first mold and the second mold appears on the tire molding surface by assembling the first mold and the second mold. It includes a vulcanizing device for vulcanizing green tires.

  The manufacturing apparatus includes a recess forming device that forms a recess in a portion of the outer surface of the green tire facing the boundary line before the green tire is inserted into the vulcanization mold. With such a recess, the raw tire and the boundary line can be arranged apart from each other when the raw tire is inserted into the vulcanization mold. As a result, it is possible to prevent the rubber from being caught between the first mold and the second mold, so that it is possible to prevent molding defects during vulcanization.

It is sectional drawing which shows the tire manufactured by the tire manufacturing method of this embodiment. It is sectional drawing explaining an example of a raw tire formation process. It is sectional drawing explaining an example of a vulcanization process. It is a fragmentary sectional view of a raw tire explaining an example of a crevice formation process. It is a perspective view showing an example of a crevice formation device. 6 is a side view of the pressing device of FIG. 5. FIG. It is a perspective view which shows another example of a recessed part formation apparatus. 8 is a side view of the pressing device of FIG. 7. FIG.

Hereinafter, an embodiment of a first invention of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a tire manufactured by the tire manufacturing method of the present embodiment (hereinafter sometimes simply referred to as “manufacturing method”). The tire 1 of the present embodiment is configured as a radial tire for passenger cars. The tire 1 is not limited to the radial tire for passenger cars.

  The tire 1 includes a carcass 6 that extends from the tread portion 2 to the bead core 5 of the bead portion 4 through the sidewall portion 3, a belt layer 7 arranged on the tire radial direction outer side of the carcass 6 and inside the tread portion 2, and a carcass. 6 and an inner liner 9 arranged inside.

  The carcass 6 is composed of one carcass ply 6A. The carcass ply 6A has carcass cords arranged at an angle of, for example, 75° to 90° with respect to the tire equator C. The carcass ply 6A of the present embodiment extends from the tread portion 2 through the pair of sidewall portions 3 and 3 in a toroidal manner between the bead portions 4 and 4. In the carcass ply 6A of the present embodiment, the inner end 6e in the tire radial direction ends without being wound up by the bead portion 4. As the carcass cord, for example, an organic fiber cord such as polyester or a steel cord is adopted.

  The bead core 5 is configured to include an inner core 5A arranged on the inner end 6e side of the carcass ply 6A and an outer core 5B. The inner core 5A is arranged on the inner surface of the carcass ply 6A in the tire axial direction. The outer core 5B is arranged on the outer surface of the carcass ply 6A in the tire axial direction. The inner core 5A and the outer core 5B are formed by spirally winding one bead wire 5c in the tire circumferential direction.

  The inner apex rubber 8i is provided on the inner surface of the inner core 5A in the tire axial direction. Further, an outer apex rubber 8o is arranged on the outer surface of the outer core 5B in the tire axial direction. These apex rubbers 8i and 8o are made of hard rubber.

  The belt layer 7 is composed of two belt plies 7A and 7B. In the belt plies 7A and 7B, the belt cords are arranged at a small angle of, for example, 10° to 40° with respect to the tire equator C. The belt plies 7A and 7B are overlapped with each other such that the belt cords intersect each other in the tire radial direction. As the belt cord, for example, a steel cord or an organic fiber cord such as aramid is adopted.

  The inner liner 9 is arranged in a substantially toroidal region 14 across the pair of bead portions 4 and 4 in a toroidal shape. The inner liner 9 is made of air impermeable butyl rubber.

Next, the manufacturing method of this embodiment will be described.
The manufacturing method of the present embodiment includes a raw tire forming step of attaching a tire constituent member to form a raw tire, and a vulcanization step of vulcanizing the raw tire.

  FIG. 2 is a cross-sectional view illustrating an example of a raw tire forming process. In the raw tire forming step of this embodiment, the rigid core 16 is used. The outer surface of the rigid core 16 substantially conforms to the shape of the inner cavity surface 14 (shown in FIG. 1) of the tire 1. Therefore, the outer surface of the rigid core 16 is configured as a tire molding surface 16S for forming the inner cavity surface 14 of the tire 1.

  In the raw tire forming step, various well-known methods using the rigid core 16 can be appropriately adopted. In this embodiment, the inner liner 9, the carcass ply 6A, the inner core 5A, the outer core 5B, the inner apex rubber 8i, the outer apex rubber 8o, the belt plies 7A and 7B, the side wall rubber 11 and the tread rubber 12 are formed. The unvulcanized raw tire 1L is formed by sequentially affixing the members for doing so to the tire molding surface 16S of the rigid core 16. Here, "unvulcanized" includes all aspects that have not been completely vulcanized, and a so-called semi-vulcanized state is included in "unvulcanized".

  FIG. 3 is a cross-sectional view illustrating an example of the vulcanization process. In the vulcanization process of the present embodiment, the vulcanization mold 17 for vulcanizing the green tire 1L is used. The vulcanization mold 17 of this embodiment includes a first mold 17A and a second mold 17B.

  The first mold 17A of the present embodiment is configured as a tread mold for molding the tread portion 2 (shown in FIG. 1) of the tire 1. The first mold 17A is provided with a groove forming portion 17t that forms the groove of the tread portion 2.

  The second mold 17B of the present embodiment is configured as a side mold for molding the sidewall portion 3 (shown in FIG. 1) of the tire 1. The second mold 17B is provided on both sides in the tire axial direction.

  By assembling the first mold 17A and the pair of second molds 17B, 17B, a tire molding surface 17S for molding the outer surface 19 of the tire 1 is formed. A boundary line 18 between the first mold 17A and the second mold 17B appears on the tire molding surface 17S. The boundary line 18 of the present embodiment is formed near the buttress portion 13 (shown in FIG. 1) of the tire 1 and is continuous in the tire circumferential direction. Further, in the present embodiment, since the pair of second molds 17B, 17B is provided, the boundary lines 18 are formed on both sides of the tire molding surface 17S in the tire axial direction.

  In the vulcanization step, first, the raw tire 1L is inserted into the vulcanization mold 17 together with the rigid core 16. When the green tire 1L is inserted into the vulcanization mold, the first mold 17A and the pair of second molds 17B and 17B are assembled.

  As for assembly of the vulcanization mold 17 of the present embodiment, the tire molding surface 17S of the lower second mold 17B (not shown) and the tire molding surface 17S of the upper second mold 17B are assembled in the same manner as in the conventional case. It is brought into contact with the outer surface 19 of the green tire 1L. At this point, the tire molding surface 17S of the first mold 17A is arranged apart from the outer surface 19 of the green tire 1L in the tire radial direction outside.

  Next, the first mold 17A is moved inward in the tire radial direction to bring the tire molding surface 17S into contact with the outer surface 19 of the green tire 1L. As a result, the first mold 17A and the pair of second molds 17B, 17B are closed, and the green tire 1L is inserted into the vulcanization mold 17 together with the rigid core 16. At this time, the groove forming portion 17t of the first mold 17A bites into the tread rubber 12 of the raw tire 1L.

  Next, after the raw tire 1L is inserted into the vulcanization mold 17, the rigid core 16 is heated. As a result, the rigid core 16 and the pre-heated vulcanization mold 17 cooperate to vulcanize and mold the green tire 1L. The outer surface 19 of the green tire 1L is molded along the tire molding surface 17S of the vulcanization mold 17 due to the rubber flow of the tread rubber 12 during vulcanization and thermal expansion.

  After the vulcanization molding, the tire 1 and the rigid core 16 are taken out from the vulcanization mold 17. Then, by taking out the rigid core 16 from the inner cavity of the tire 1, the tire 1 shown in FIG. 1 can be manufactured.

  By the way, 1 L of raw tires hold|maintain a lot of air between tire component members. Therefore, the outer diameter 19 of the green tire 1L is larger than the outer diameter of the vulcanized tire 1 (shown in FIG. 1). Therefore, when the green tire 1L is inserted into the vulcanization mold 17, when the first mold 17A and the pair of second molds 17B, 17B are assembled, the outer surface 19 of the green tire 1L facing the boundary line 18 is formed. A so-called rubber bite that is partly sandwiched between the molds 17A and 17B is likely to occur.

  The rubber sandwiched between the first mold 17A and the second mold 17B remains in the molds 17A and 17B as burnt rubber even after the raw tire 1L is vulcanized. Such burnt rubber adheres to the tire to be subsequently vulcanized and molded. Therefore, there is a problem that the tire is defectively molded and the productivity is lowered.

  In the manufacturing method of the present embodiment, before inserting the raw tire 1L into the vulcanization mold 17, the concave portion 21 is formed in the portion P1 (shown in FIG. 2) on the outer surface 19 of the raw tire 1L that faces the boundary line 18. The recess forming step is performed. Here, the portion P1 facing the boundary line 18 on the outer surface 19 of the green tire 1L means that the boundary line 18 of the vulcanization mold 17 and the outer surface 19 of the green tire 1L are not formed when the recess 21 is not formed. This is a region including a contacting point. Since there is a pair of boundary lines 18 corresponding to the pair of second molds 17B and 17B, a pair of portions P1 also exists. FIG. 4 is a partial cross-sectional view of a raw tire illustrating an example of the recess forming step.

  In the recess forming step, after the raw tire 1L is inserted into the vulcanization mold 17, the tire axial distance between the pair of portions P1 (shown in FIG. 2) facing the boundary line 18 on the outer surface 19 of the raw tire 1L. However, the concave portion 21 is formed so as to be smaller than the tire axial direction interval of the tire molding surface 17S near the pair of boundary lines 18.

  In the present embodiment, since the boundary line 18 is formed continuously in the tire circumferential direction, it is desirable that the recess 21 is also continuously formed in the tire circumferential direction. The recesses 21 of the present embodiment are provided on both sides in the tire axial direction. The recess 21 of the present embodiment is formed in a triangular shape in cross section, but is not limited to such an aspect.

  In the recess forming step of the present embodiment, the outer surface 19 of the green tire 1L is cut to form the recess 21 (cutting step). For cutting the recess 21, for example, a tire groover (not shown) for carving the groove of the tire 1 can be used. By using such a tire groove, the recess 21 can be easily formed in the green tire 1L.

  By forming such a recess 21 in the raw tire 1L, the raw tire 1L and the boundary line 18 can be arranged apart from each other after the raw tire 1L is inserted into the vulcanization mold 17. As a result, rubber trapping between the first mold 17A and the second mold 17B can be prevented.

  Even if the concave portion 21 is formed in the raw tire 1L, the rubber flow of the tread rubber 12 or the like at the time of vulcanization or thermal expansion of the rubber causes the tire 1 to move along the tire molding surface 17S of the vulcanization mold 17. The outer surface 19 is molded. Therefore, the molding failure of the tire 1 does not occur. It should be noted that, after the first mold 17A and the pair of second molds 17B and 17B are assembled, the gap formed at the boundary lines 18 and 18 is very small (for example, about 1 μm to 40 μm). Therefore, at the time of vulcanization, even if the outer surface 19 of the green tire 1L faces the boundary line 18, it is possible to prevent rubber from entering between the first mold 17A and the second mold 17B. Therefore, burnt rubber does not remain on the molds 17A and 17B.

  Further, after the green tire 1L is inserted into the vulcanization mold 17 (shown in FIG. 3), the shortest distance L1 from the boundary line 18 of the vulcanization mold 17 is 1.0 mm to 3.0 mm. It is desirable that the recess 21 of the green tire 1L be formed. If the shortest distance L1 is less than 1.0 mm, it may not be possible to sufficiently prevent the rubber from being caught between the first mold 17A and the second mold 17B. On the other hand, when the shortest distance L1 exceeds 3.0 mm, the rubber volume of the green tire 1L is greatly reduced, which may cause defective molding. From this point of view, the shortest distance L1 is preferably 1.5 mm or more, and more preferably 2.5 mm or less.

  Furthermore, after the raw tire 1L is inserted into the vulcanization mold 17 (shown in FIG. 3), the width W1 of the concave portion 21 of the raw tire 1L is preferably set to 4.0 mm to 12.0 mm. If the width W1 is 4.0 mm or less, it may not be possible to sufficiently prevent rubber entrapment between the first mold 17A and the second mold 17B. Conversely, if the width W1 exceeds 12.0 mm, the rubber volume of the green tire 1L may be significantly reduced. From this point of view, the width W1 is preferably 5.0 mm or more, and more preferably 11.0 mm or less.

  In the recess forming step of the present embodiment, a mode in which the cutting process of cutting the outer surface 19 of the green tire 1L is performed is exemplified, but the mode is not limited to such a mode. For example, the outer surface 19 of the green tire 1L may be pressed to form the recess 21 (pressing step).

  FIG. 5 shows an example of the recess forming apparatus M1 that performs the recess forming step. The recess forming device M1 includes a pressing device M10 that performs a pressing process. The pressing device 10 includes a pressing unit 26 that is pressed against the outer surface of the raw tire 1L, an arm 31 that supports the pressing unit 26, and a driving unit (not shown) that presses the pressing unit 26 against the outer surface of the raw tire 1L via the arm. ) Is included.

  FIG. 6 is a side view of the pressing means 26. The pressing unit 26 of the embodiment includes a base 27, a pair of support pieces 28, 28, and a roller 29. The base 27 is formed in a plate shape that is substantially rectangular in a plan view. The base portion 27 is movably supported by the arm 31 and a driving unit (not shown) with respect to the raw tire 1L. The pair of support pieces 28, 28 are fixed so as to project from one surface of the base portion 27. The pair of support pieces 28, 28 are arranged apart from each other in the length direction of the base 27 (in the present embodiment, the vertical direction).

  The roller 29 is formed in a disc shape. The roller 29 is rotatably supported by a support shaft 33 extending between the pair of support pieces 28. As shown in FIG. 6, a molding surface 29 s for forming the concave portion 21 is formed on the outer peripheral surface of the roller 29. The molding surface 29s of the present embodiment is inclined with respect to the axial center direction of the roller 29 so that the recess 21 (shown in FIG. 4) as described above is formed.

  In the pressing step, first, the molding surface 29s of the roller 29 is pressed against the portion P1 (shown in FIG. 2) facing the boundary line 18 on the outer surface 19 of the green tire 1L. Then, the green tire 1L is rotated in the tire circumferential direction. In the present embodiment, the rotation of the green tire 1L is performed via a gripping means (not shown) fixed to the rigid core 16.

  The rotation of the green tire 1L in the tire circumferential direction causes the roller 29 to roll on the outer surface 19 of the green tire 1L. By the rolling of the roller 29, the portion P1 (shown in FIG. 2) facing the boundary line 18 on the outer surface 19 of the raw tire 1L is continuously pressed in the tire circumferential direction. As a result, the recess 21 is formed in the green tire 1L.

  In order to effectively form such a concave portion 21, it is desirable that the roller 29 is heated. As a result, the portion of the green tire 1L that is pressed against the roller 29 is softened by the heat of the roller 29, and the recess 21 can be efficiently formed.

  The heating means for heating the roller 29 can be appropriately adopted. In the present embodiment, the roller 29 is heated by the heater (not shown) embedded in the pair of support pieces 28, 28 via the pair of support pieces 28, 28 and the support shaft 33. The roller 29 may be heated by a heater (not shown) embedded in the roller 29. The temperature of the roller 29 can be set appropriately, but is preferably set to, for example, 45° C. to 55° C. (50° C. in the present embodiment).

  The force (pressing force) for pressing the molding surface 29s of the roller 29 against the green tire 1L can be appropriately set depending on the structure of the tire 1 and the hardness of the unvulcanized rubber of the green tire 1L. For example, in the case of the raw tire 1L of a radial tire for passenger cars, the pressing force is preferably set to about 150N to 300N (230N in this embodiment).

  Further, the rotation speed Va (shown in FIG. 5) of the raw tire 1L can be appropriately set according to the structure of the tire 1 and the like. If the rotation speed Va is low, it may take a long time to press the raw tire 1L. On the other hand, when the rotation speed Va is high, the raw tire 1L cannot sufficiently follow the pressure of the roller 29, and the recess 21 may not be formed accurately. From this point of view, the rotation speed Va is preferably about 3 degrees/second to 8 degrees/second (5 degrees/second in this embodiment).

  The driving means (not shown) for moving the pressing means 26 has a size of the outer surface 19 (shown in FIG. 2) of the raw tire 1L and a size of the tire molding surface 17S (shown in FIG. 3) of the vulcanization mold 17. Based on this, it is desirable that it is automatically controlled. As a result, after the raw tire 1L is inserted into the vulcanization mold 17, the recess 21 that can separate the raw tire 1L and the boundary line 18 can be reliably formed. Moreover, since the recess forming process can be automated, the manufacturing cost can be suppressed. It is desirable that the dimensions of the outer surface 19 of the green tire 1L and the dimensions of the tire molding surface 17S of the vulcanization mold 17 are measured in advance before the recess forming step.

  In the recess forming step of the present embodiment, a mode in which either a cutting step of cutting the outer surface 19 of the raw tire 1L or a pressing step of pressing the outer surface 19 of the raw tire 1L is exemplified, but However, the embodiment is not limited to this. For example, both the cutting process and the pressing process may be performed. The order of performing the cutting process and the pressing process can be set as appropriate. For example, the pressing step may be performed after the cutting step. Thereby, since the roller 29 is pressed after the outer surface 19 of the green tire 1L is cut, the recess 21 can be formed more quickly. Further, since the cutting surface of the green tire 1L is leveled by the rollers 29, rubber trapping between the first mold 17A and the second mold 17B can be effectively prevented.

  The manufacturing method of the present embodiment exemplifies a mode in which the recess is formed on the outer surface 19 of the green tire 1L formed on the rigid core 16, but the mode is not limited to such a mode. For example, a concave portion 21 is formed on the outer surface of a green tire (not shown) formed by expanding an annular tire constituent member attached to a cylindrical forming drum (not shown) into a toroid shape by a bladder (not shown). May be formed. Thereby, also in the manufacturing method of this embodiment, it is possible to prevent the rubber from being caught between the first mold 17A and the second mold 17B. In addition, in this embodiment, it is desirable that the concave portion 21 be formed in a state where the raw tire 1L is inflated.

  FIG. 7 shows a recess forming apparatus M1 for performing the recess forming step. FIG. 8 shows a pressing device M10 included in the recess forming device M1. As shown in FIGS. 7 and 8, the recess forming step may include a vibrating step of vibrating the roller 29. In the process of forming the recess 21 on the outer surface 19 of the green tire 1L in the recess forming step, the roller 29 vibrates, so that the formation of the recess 21 is promoted. As a result, the time required for the recess forming step can be shortened and the tire production efficiency is improved.

  Hereinafter, the tire manufacturing apparatus of the embodiment of the second invention will be described. The tire manufacturing apparatus includes a recess forming device M1 shown in FIGS. The recess forming device M1 includes a pressing device M10 that performs a pressing process. The pressing device M10 includes a pressing unit 26 and the like. The pressing means 26 includes a base portion 27, a pair of supporting pieces 28, 28, and a roller 29. The pressing device M10, the pressing means 26, the base portion 27, the support piece 28, the roller 29, etc. have already been described in the first invention.

  The pressing means 26 forms a concave portion 21 at a position facing the boundary line 18 on the outer surface 19 of the raw tire 1L. The recess 21 extends in the tire axial direction. Since the boundary line 18 between the first mold 17A and the second mold 17B is continuously formed in the tire circumferential direction, it is desirable that the recess 21 be continuously formed in the tire circumferential direction. By forming the concave portion 21 by the pressing means 26, when the raw tire 1L is inserted into the vulcanization mold 17, the raw tire 1L and the boundary line 18 can be arranged apart from each other. As a result, it is possible to prevent the rubber from being caught between the first mold 17A and the second mold 17B, so that it is possible to prevent defective molding during vulcanization.

  In the present embodiment, the pressing device M10 includes a heating unit (not shown) that heats the pressing unit 26. Examples of the heating means include a heater having electric energy as a heat source. The heating means is embedded in the support piece 28, the roller 29, or the like, for example. The heat of the heating means is transferred to the outer surface 19 of the raw tire 1L via the roller 29, and the rubber of the raw tire 1L is softened. Thereby, the roller 29 can be easily embedded in the rubber of the outer surface 19, and the recess 21 can be efficiently formed.

  The pressing device M10 shown in FIG. 7 differs from the pressing device M10 shown in FIG. 5 in that it includes a vibrating means 41 for vibrating the pressing means 26. The form of the vibrating means 41 is not particularly limited. For example, an impulse hammer may be used and an inertial exciter may be used. In the present embodiment, as the vibrating means 41, a so-called modal inertial exciter that excites the test product by using the reaction force of the vibration of the inertial mass can be applied. The modal inertial exciter is preferable because it has high reproducibility of vibration and can be easily mounted on the pressing device M10.

  The form in which the vibrating means 41 is mounted is not particularly limited. In this embodiment, as shown in FIGS. 7 and 8, the vibrating means 41 is mounted on the base portion 27, but the vibrating means 41 may be directly mounted on the roller 29, and the arm 31 may be mounted on the arm 31. The vibrating means 41 may be mounted.

  The vibrating means 41 drives and vibrates the roller 29. As a result, the roller 29 is pressed against the outer surface 19 of the green tire 1L while vibrating, and the formation of the recess 21 is promoted. Therefore, the time required to form the recess 21 can be shortened, and the production efficiency of the pneumatic tire is improved.

  The vibrating means 41 drives and vibrates the roller 29 so as to include an amplitude component in the axial direction of the raw tire 1L. This makes it possible to further reduce the time required to form the recess 21.

  When the roller 29 is vibrated by the vibrating means 41, it is desirable that the vibration frequency and amplitude take into consideration the influence on the equipment (for example, loosening of the bolt). The vibration frequency of the vibrating means 41 is preferably 5 Hz or higher, for example. This makes it possible to further reduce the time required to form the recess 21.

  If the temperature of the roller 29 is too high, the rubber of the outer surface 19 against which the roller 29 is pressed will be burnt or peeled off. On the other hand, if the temperature of the roller 29 is too low, the time required to form the recess 21 may not be sufficiently shortened. Therefore, the temperature of the roller 29 is appropriately determined in consideration of the rubber state of the outer surface 19 where the recess 21 is formed and the time required to form the recess 21. In the pressing device M10 shown in FIG. 7, it is possible to set the temperature of the roller 29 lower than that of the pressing device M10 shown in FIG. 5 and reduce the time required to form the recess 21.

  Various waveforms can be applied to the vibration waveform of the vibrating means 41. For example, the vibration wave of the vibrating means 41 is not only a sine wave having a single frequency and a single amplitude, but also a random wave formed by combining a plurality of sine waves having different frequencies and amplitudes, or a short time A shock wave or the like that causes a specific waveform can be set appropriately. Although any vibration wave can be used, the time required to form the concave portion 21 can be shortened, but a sine wave that is regular vibration can stably obtain the above-described time reduction effect.

  Although a particularly preferred embodiment of the present invention has been described above in detail, the present invention is not limited to the illustrated embodiment and can be carried out by being modified into various aspects.

  For example, an annular or arcuate pressing tool may be applied to the pressing means 26 instead of the roller 29. When the annular pressing tool is applied, the time required to form the recess 21 can be further shortened.

  Ten green tires each having the basic structure shown in FIG. 2 were manufactured, and a vulcanization step of vulcanizing the green tires was performed (Example 1, Example 2 and Comparative Example). In Example 1 and Example 2, before inserting the green tire into the vulcanization mold, the concave portion forming step of forming a concave portion on the outer surface of the raw tire facing the boundary line was performed. On the other hand, in the comparative example, the recess forming step was not performed.

  In the recess forming step of Example 1, the pressing step of forming the recess by pressing the outer surface of the green tire was performed. In the pressing process of Example 1, the pressing means shown in FIGS. 5 and 6 was used. In the recess forming step of Example 2, the cutting step of forming the recess by cutting the outer surface of the green tire was performed. In the cutting process of Example 2, a tire groover (not shown) was used.

Then, in Examples 1, 2 and Comparative Example, after the vulcanization step, the presence or absence of rubber bite in which a part of the outer surface of the raw tire was sandwiched between the molds was visually confirmed. The common specifications are as follows.
Tire size: 245/45R18
Example 1 and Example 2:
Shortest distance L1: 2.0 mm
Width of recess W1:8.0mm
Example 1:
Roller temperature: 50℃
Raw tire rotation speed: 3 rotations Raw tire rotation speed Va: 5 degrees/second
Pressing force on raw tires: 230N

  As a result of the test, in Example 1 and Example 2, all the raw tires (total of 10 tires) did not cause rubber bite. On the other hand, in the comparative example, rubber bite occurred in 10 of all the raw tires (10 in total). Therefore, it was confirmed that Example 1 and Example 2 can prevent the rubber from being trapped between the molds and prevent defective molding during vulcanization.

  Further, the recess 21 was formed using the recess forming device M1 not including the vibrating means 41 shown in FIG. 5 and the recess forming device M1 including the vibrating means 41 shown in FIG. The temperature of the roller 29 was set to 50° C., and the time required to form the recess 21 was measured while changing the rotation speed of the green tire 1L. In the recess forming device M1 not including the vibrating means 41, the time required to form the recess 21 was 3 rotations at the rotation speed Va of 5 degrees/second, that is, 216 seconds. On the other hand, in the recess forming device M1 including the vibrating means 41, the time required to form the recess 21 was shortened to two rotations at the rotation speed Va of 9 degrees/second, that is, 40 seconds. From the above, it was confirmed that the vibrating means 41 shortens the time required to form the concave portion 21 and improves the production efficiency of the pneumatic tire.

1L green tire 17 vulcanization mold 17A first mold 17B second mold 18 boundary line 19 outer surface 21 recess 26 pressing means 29 roller 41 vibrating means M1 recess forming device M10 pressing device

Claims (16)

On the rigid core, a raw tire forming step of forming a raw tire by sequentially attaching unvulcanized tire constituent members,
By assembling the first mold and the second mold, the green tire is placed together with the rigid core in a vulcanization mold in which a boundary line between the first mold and the second mold appears on the tire molding surface. A method of manufacturing a tire, which comprises a vulcanization step of vulcanizing by charging the tire molding surface of the vulcanizing mold and the outer surface of the rigid core to the raw tire .
A method for manufacturing a tire, comprising a step of forming a concave portion on a portion of the outer surface of the raw tire facing the boundary line before the raw tire is inserted into the vulcanization mold. The first mold is a tread mold for molding the tread portion of the tire,
The method for manufacturing a tire according to claim 1, wherein the second mold is a side mold for molding a sidewall portion of the tire.   The tire manufacturing method according to claim 1, wherein the recess forming step includes a cutting step of forming the recess by cutting an outer surface of the green tire.   The tire manufacturing method according to claim 1, wherein the recess forming step includes a pressing step of forming the recess by pressing an outer surface of the green tire. A vulcanization step of vulcanizing the green tire with a vulcanization mold in which a boundary line between the first mold and the second mold appears on the tire molding surface by assembling the first mold and the second mold A method of manufacturing a tire,
Before inserting the raw tire into the vulcanization mold, including a recess forming step of forming a recess in the portion facing the boundary line on the outer surface of the raw tire,
The recess forming step includes a pressing step of forming the recess by pressing the outer surface of the raw tire, the pressing step is performed by pressing a rotatable roller to the outer surface of the raw tire. A method for manufacturing a tire characterized by the above.   The tire manufacturing method according to claim 5, wherein the roller is heated.   The method for manufacturing a tire according to claim 5, wherein the recess forming step includes a vibration step of vibrating the roller. On the rigid core, a raw tire forming device for forming a raw tire by sequentially attaching unvulcanized tire constituent members,
By assembling the first mold and the second mold, the green tire is placed together with the rigid core in a vulcanization mold in which a boundary line between the first mold and the second mold appears on the tire molding surface. A device for manufacturing a tire including a vulcanizing device that is vulcanized by charging the tire molding surface of the vulcanizing mold and the outer surface of the rigid core to the green tire .
A tire manufacturing apparatus comprising: a recess forming device that forms a recess on a portion of the outer surface of the green tire facing the boundary line. The first mold is a tread mold for molding the tread portion of the tire,
The tire manufacturing apparatus according to claim 8, wherein the second mold is a side mold that molds a sidewall portion of the tire.   The tire manufacturing apparatus according to claim 8, wherein the recess forming device includes a pressing device that presses the outer surface of the green tire to form the recess.   The tire manufacturing apparatus according to claim 10, wherein the pressing device includes a pressing unit that is pressed against the outer surface of the raw tire.   The tire manufacturing apparatus according to claim 11, further comprising heating means for heating the pressing means. A vulcanization device for vulcanizing a raw tire with a vulcanization mold in which a boundary line between the first mold and the second mold appears on the tire molding surface by assembling the first mold and the second mold. A tire manufacturing apparatus,
A recess forming device that forms a recess in a portion of the outer surface of the green tire facing the boundary line,
The recess forming device includes a pressing device that forms the recess by pressing the outer surface of the green tire,
The pressing device includes a pressing means pressed against the outer surface of the raw tire,
The pressing device manufacturing apparatus of the tire, characterized in that it comprises a vibration means for vibrating the pressing means.   The tire manufacturing apparatus according to claim 13, wherein the vibrating means vibrates the pressing means so as to include a vibration component in the axial direction of the raw tire.   15. The tire manufacturing apparatus according to claim 13, wherein the vibrating means vibrates the pressing means at a frequency of 5 Hz or higher. A vulcanization device for vulcanizing a raw tire with a vulcanization mold in which a boundary line between the first mold and the second mold appears on the tire molding surface by assembling the first mold and the second mold. A tire manufacturing apparatus,
A recess forming device that forms a recess in a portion facing the boundary line on the outer surface of the green tire,
The recess forming device includes a pressing device that forms the recess by pressing the outer surface of the green tire,
The pressing device includes a devoted pressing means pressing the outer surface of the raw tire, said pressing means, apparatus for manufacturing tires, which is a rotatable roller.

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