JP2009178909A - Method of manufacturing pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a pneumatic tire which prevents the deformation of tire constituent parts inside a tread when vulcanizing, even in a case where a peripheral groove is wide or deep. <P>SOLUTION: When a green tire 20 wherein a tread groove 26K corresponding to the peripheral groove is formed on the surface of the tread 24 is set to a vulcanizing mold 10 to be subjected to vulcanization molding, a ring member 40 is prepared which is formed by connecting a plurality of circular arc-shaped ring pieces by a rubber member, has the same curvature as the peripheral curvature on the inner surface side of a vulcanizing mold 10, and has a protruded part 41 extending along the peripheral direction of the tire to be fitted to the tread groove 26K formed inside a radial direction. After the protruded part 41 of the ring member 40 is fitted to the tread groove 26K, the green tire 20 is subjected to vulcanization molding. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a pneumatic tire, and more particularly to a pneumatic tire manufactured by vulcanization molding of a raw tire having a circumferential groove formed in advance on its surface, such as an aircraft tire.

An aircraft radial tire generally includes a belt layer on the periphery of a crown portion of a toroidal radial carcass, and includes a tread made of a rubber member (tread rubber) on the outer side in the tire circumferential direction of the belt layer. A circumferential groove extending continuously along the tire circumferential direction is formed on the ground contact surface in contact with the road surface of the tread. Such a radial tire for an aircraft usually produces tire components such as a carcass, a belt layer, and a tread made of unvulcanized rubber, an organic fiber cord, and the like, and the plurality of tire components are sequentially formed on a molding drum. After bonding and molding an unvulcanized green tire (raw tire), the molded raw tire is set in a vulcanizing mold, and pressure is applied to the inside of the raw tire so that the outer surface of the raw tire is The raw rubber is pressure-bonded to the inner wall of the heated vulcanization mold, and the raw rubber is vulcanized with heat and pressure.
As shown in FIGS. 5A and 5B, the inner surface (surface on the cavity side) 10a of the vulcanizing mold 10A extends continuously in the tire circumferential direction to form a circumferential groove of the tire. A rib 10b called a bone portion is provided, and the rib 10b bites into a rubber member (rubber member for tread) constituting the tread 24 of the raw tire 20A at the time of vulcanization molding, and a plurality of circumferences are formed on the tread 24. A directional groove 26 is formed. 5 (a) and 5 (b), 21 is a carcass forming a tire skeleton, 22a and 22b are first and second belt layers disposed on the outer side in the tire radial direction of the carcass 21, and 23 is the above. The belt protective layer is disposed on the inner side in the tire radial direction of the tread 24 and covers the belt layers 22a and 22b.
Conventionally, a flat tread rubber member having no irregularities on its surface is often bonded to the outer peripheral surface of the raw tire 20A. Therefore, as shown in FIG. It is formed flat. The tread rubber member having the above flat surface is obtained by continuously extruding a raw material made of unvulcanized rubber or the like into a predetermined cross-sectional shape by an extruder and cutting it into a predetermined length. Molded.

When forming a circumferential groove in the green tire 20A having the flat outer peripheral surface, the ridge 10b provided on the inner surface 10a of the vulcanizing mold 10A eliminates a large amount of rubber during vulcanization. It is necessary to bite into the rubber member. Along with this, rubber is pushed inwardly in the tire radial direction, which is the protruding direction of the ridge 10b. Therefore, particularly when the circumferential groove 22 is wide or deep, the belt protective layer 23 or A large pressing force acts on the tire components located on the inner side in the tire radial direction of the protrusion 10b such as the belt layers 22a and 22b. As a result, as shown in FIG. 5 (b), the portion of the tire component on which the pressing force is applied may be deformed in a ring shape to form a wave shape (here, the belt protective layer 23 is deformed). Is illustrated).
By the way, in the case of radial tires for aircraft, when the tread is worn to some extent, regeneration by recapping is performed, but if the belt protective layer arranged under the tread is waved, it is difficult to correct for recapping. It becomes difficult to use the tire as a stand tire for regeneration.
Therefore, in order to solve such a problem, as shown in FIGS. 6A and 6B, using the stitcher roll 30 or the like, a portion of the tread rubber member that constitutes the tread 24 is applied to the protrusion 10b. A raw tire 20B having a groove width wider than the width of the ridge 10b and having a groove depth 26k having a groove depth smaller than the height of the ridge 10b is prepared in advance. There has been proposed a method of suppressing the amount of waves of the belt protective layer 23, the belt layers 22a, 22b, etc. by setting in the vulcanization mold 10A and performing vulcanization molding (see, for example, Patent Document 1). .
JP 2003-236949 A

  However, in the method of previously forming the groove 26k in the tread 24, when the groove 26k and the position of the protrusion 10b of the vulcanizing mold 10A are shifted, the flow of rubber around the groove 26k is increased. However, there is a problem that the wave is easily generated because bear or air enters the surface of the tread 24 or rubber flow is deteriorated.

  The present invention has been made in view of the conventional problems, and even when the circumferential groove is wide or the groove depth is deep, a pneumatic tire in which the tire component inside the tread does not deform during vulcanization. It aims at providing the manufacturing method of.

According to a first aspect of the present invention, there is provided a belt layer, a belt protective layer provided on the outer side in the tire radial direction of the belt layer, and a tread rubber provided on the outer side in the tire radial direction of the belt protective layer. A method for manufacturing a pneumatic tire in which a green tire is molded and then the molded green tire is vulcanized using a vulcanization mold, and the tire is formed on a surface of a tread rubber of the molded green tire. The ring member is formed with a circumferential groove extending along the circumferential direction, and the ring member includes a projection having a projection that fits on the inner circumferential side of the circumferential groove. The raw tire fitted with is set in a vulcanization mold and vulcanized.
According to a second aspect of the present invention, in the method for manufacturing a pneumatic tire according to the first aspect, a convex portion or a concave portion is provided on the outer peripheral side of the ring member, and the convex portion or the concave portion of the vulcanization mold is provided. After the concave portion or the convex portion into which the convex portion or the concave portion is fitted is provided in the facing portion and the convex portion or the concave portion of the ring member is fitted into the concave portion or the convex portion of the vulcanization mold, The raw tire is vulcanized and molded.
Invention of Claim 3 is a manufacturing method of the pneumatic tire of Claim 1 or Claim 2, Comprising: The said ring member connects the several ring piece which consists of a metal or an alloy with a rubber member. It is formed.
According to a fourth aspect of the present invention, in the method for manufacturing a pneumatic tire according to any one of the first to third aspects, the metal or alloy constituting the ring piece is at least on the cavity side of the vulcanization mold. The same metal or alloy as the constituent metal or alloy is used.

According to the present invention, when a green tire having a circumferential groove formed on the tread surface is set in a vulcanization mold and vulcanized, a ring having a protrusion that fits into the circumferential groove on the inner surface side. A member is prepared, and the protrusion of the ring member is fitted into the circumferential groove of the green tire, and then the raw tire is vulcanized to prevent displacement of the circumferential groove of the green tire. As a result, the waving (wave) of the belt protective layer can be suppressed, and appearance defects such as bears generated on the tread surface can be reduced.
At this time, a convex portion (or a concave portion) is provided on the outer peripheral side of the ring member, and the convex portion (or the concave portion) is fitted into a portion facing the convex portion (or the concave portion) of the vulcanization mold. A concave portion (or a convex portion) to be combined is provided, and the ring member fitted to the raw tire on the inner surface side is fitted to the vulcanization mold, and then the raw tire is used as the vulcanization mold. If set and vulcanized, it is possible to more reliably prevent displacement of the circumferential groove of the raw tire. Moreover, since the shape of the cavity of a vulcanization mold can be simplified, manufacture of a vulcanization mold becomes easy.
Moreover, since the ring member is formed by connecting a plurality of ring pieces made of metal or alloy with a rubber member, the ring member can be easily manufactured.
Further, if the metal or alloy constituting the ring member is the same as the metal or alloy constituting at least the cavity side of the vulcanization mold, the adhesion between the ring member and the vulcanization mold during vulcanization Therefore, the occurrence of groove shift during vulcanization can be eliminated.

Hereinafter, the best mode of the present invention will be described with reference to the drawings.
First, as shown in FIG. 1, the carcass 21, which is a tire component, the first and second belt layers 22a and 22b, the belt protective layer 23, and the tread 24 are sequentially bonded on a molding drum and molded. A vulcanized green tire (raw tire) 20 is produced.
The carcass 21 is a member that forms a tire skeleton, in which a plurality of reinforcing members (hereinafter referred to as cords) made of fibers such as steel cord or nylon are arranged in parallel and formed into a sheet shape with unvulcanized rubber. A pair of bead cores 25 </ b> C disposed in the bead portion 25 is disposed in a toroidal shape. When the carcass 21 is disposed on the tire, the cord angle of the cord (inclination angle with respect to the tire equator direction) is 90 °.
On the other hand, the first and second belt layers 22a and 22b are cords that are arranged on the outer side in the tire radial direction of the carcass 21 and twisted with a fiber such as steel cord or aromatic polyamide, and the cord angle with respect to the equator direction is It is 20 ° to 70 °. The first and second belt layers 22a and 22b are arranged so as to cross each other.
The belt protective layer 23 protects the first and second belt layers 22a and 22b, and is disposed on the outer side in the tire radial direction of the first and second belt layers 22a and 22b. The belt protective layer 23 is formed by covering one or a plurality of cords with rubber and winding them around the tread portion so as to be spirally wound. The cord angle with respect to the equator direction is 0 ° to 5 °. .
The tread 24 is a rubber member (tread rubber member) disposed on the outer side in the tire circumferential direction of the belt protective layer 23, and is not vulcanized at this stage. In this example, as a tread, a tread 24 in which a groove 26K having a shape substantially the same as a circumferential groove 26 formed in a tire and extending in the tire circumferential direction (hereinafter referred to as a tread groove) 26K is formed on a tread rubber member in advance. Used.

Next, as shown in FIG. 2, a plurality of ring members 40 having protrusions 41 on the inner peripheral side are prepared, and these ring members 40 are fitted into the respective tread grooves 26 </ b> K formed in the tread 24. . The protrusion 41 of the ring member 40 has a shape corresponding to the shape of each tread groove 26 </ b> K formed in the tread 24.
Specifically, as shown in FIG. 3A, the ring member 40 is composed of a plurality of arc-shaped ring pieces 40 </ b> R having the same curvature as the circumferential curvature on the inner surface side of the vulcanizing mold 10 with a rubber member 43. As shown in FIG. 3 (b) (AA sectional view in FIG. 3 (a)), the tire circumference is the same shape as the protrusion 10b of the conventional vulcanization mold 10A. The projection 41 extending along the direction is provided on the radially inner side, and the outer side in the radial direction has a substantially triangular cross-sectional shape arranged such that the base is joined to the projection 41 and the apex is radially outward. A convex portion 42 having a shape is provided.
When the ring member 40 is attached to the tread 24, the protrusion 41 is fitted into the tread groove 26K provided on the tread 24 of the raw tire 20, as shown in FIG. The length of the bottom side 42a of the protrusion 42 is the width of the circumferential groove provided in the tire 20 so that the protrusion 41 does not unnecessarily bite into the tread groove 26K. It is formed larger than the width W (see FIG. 3B).
Next, as shown in FIG. 4A, the raw tire 20 having the ring member 40 attached to the tread 24 is set in the vulcanizing mold 10 and vulcanized. On the inner surface side of the vulcanizing mold 10 of this example, not the protrusion 10b of the conventional vulcanizing mold 10A, but a concave portion 10c having a cross-sectional shape corresponding to the convex portion 42 having the substantially triangular shape is formed. ing. Therefore, after attaching the ring member 40 to the tread 24, the convex portion 42 provided on the outer periphery of the ring member 40 is fitted into the concave portion 10 c provided on the inner periphery of the vulcanizing mold 10. The raw tire 20 is set in the vulcanizing mold 10 and then the raw tire 20 is vulcanized to form a tire 20M having a circumferential groove 26 as shown in FIG. Can be obtained.
At this time, the metal or alloy constituting the ring piece 40R is preferably the same metal or alloy as the metal or alloy constituting the inner surface 10a side of the vulcanizing mold 10. Thereby, the deviation between the ring member 40 and the vulcanization mold 10 during vulcanization due to thermal expansion or the like can be eliminated, and the adhesion between the ring member 40 and the vulcanization mold 10 is improved. It is possible to prevent a bear or air from entering the surface.
Further, as described above, the protrusion 41 of the ring member 40, which corresponds to the bone portion of the mold, is fitted in the tread groove 26K, so that the position of the circumferential groove 26 does not shift. Therefore, the protrusion 41 does not apply a large pressing force to the belt protective layer 23, the belt layers 22a and 22b, etc. during vulcanization, and therefore the first and second belt layers 22a on the inner side of the tread 24. , 22b as well as the concave deformation of the belt protective layer 23 disposed immediately below the tread 24 can be effectively suppressed. Further, since there is no deterioration of the rubber flow due to the displacement of the circumferential groove 26, the generation of bears can be greatly reduced.

Thus, in this best mode, when the raw tire 20 in which the tread groove 26K corresponding to the circumferential groove 26 is formed on the surface of the tread 24 is set in the vulcanization mold 10 and vulcanized, A plurality of arc-shaped ring pieces having protrusions 41 extending in the tire circumferential direction and fitted in the tread groove 26K on the inner side in the direction, and having the same curvature as the circumferential curvature on the inner surface side of the vulcanization mold 10 Since the ring member 40 formed by connecting 40R with the rubber member 43 is prepared, and the protrusion 41 of the ring member 40 is fitted into the tread groove 26K, the raw tire 20 is vulcanized and molded. Moreover, the shift | offset | difference of the position of the circumferential groove | channel of the raw tire 20 can be prevented, and the wavy of the belt protective layer 23 can be suppressed. In addition, since there is no deterioration of the rubber flow due to the displacement of the circumferential grooves, the occurrence of bears can be greatly reduced.
At this time, on the radially outer side of the ring member 40, the base is joined to the protruding portion 41, and the cross-sectional shape disposed so that the apex is radially outward forms a substantially triangular convex portion 42, and If the concave portion 10c into which the convex portion 42 is fitted is provided in a portion facing the convex portion 42 of the vulcanizing mold 10, the shape of the cavity of the vulcanizing die 10 can be simplified. Further, the vulcanizing mold 10 can be easily manufactured.
Moreover, since the ring member 40 is formed by connecting a plurality of ring pieces 40R made of metal or alloy with a rubber member, the ring member 40 can be easily manufactured.
Further, if the ring piece 40R is the same as the metal or alloy constituting the inner surface 10a side of the vulcanization mold 10, the adhesion between the ring member 40 and the vulcanization mold 10 during vulcanization is improved. Therefore, it is possible to eliminate the occurrence of groove shift during vulcanization.

In the best mode, the type of tire is not specified. However, in the present invention, the circumferential groove 26 such as a radial tire for an aircraft used in an aircraft such as a jet passenger aircraft is wide, This is particularly effective when manufacturing a tire having a deep depth.
The ring member 40 may be integrally cast by die casting or the like. However, as in this example, a plurality of arc-shaped ring pieces 40R are prepared, and these ring pieces 40R are connected by a rubber member 43. It is easier to manufacture. Further, the member for connecting the ring piece 40R is not limited to the rubber member, and a connecting piece made of the same material as the ring piece 40R may be used. In this case, it is preferable that the connecting piece has a joint structure.
Further, a concave portion may be formed on the outer side in the radial direction of the ring piece 40R, and a convex portion into which the concave portion is fitted may be provided in a portion facing the concave portion 42 of the vulcanizing mold 10.
In the above example, the ring member 40 is configured by connecting twelve ring pieces 40R with a rubber member. However, the number of the ring pieces 40R is not limited thereto, and the diameter of the tire, the shape of the circumferential groove, and the like. May be determined as appropriate.

表１から明らかなように、本発明のタイヤでは、ウエーブ量（σ）も極めて少なく、かつ、外観不良も見られなかった。これにより、加硫前にトレッドに周方向溝に相当するトレッド溝を形成した場合でも、リング部材を用いないと、金型の突条と上記トレッドとの位置ずれが生じてしまうことがわかったので、本発明の有効性が確認された。 In order to confirm the effect of the present invention, a raw tire having the same tread pattern and having a tread groove corresponding to a circumferential groove formed on the tread before vulcanization is prepared. Tires vulcanized with the ring member (invention) and tires vulcanized without the ring member (prior art) are manufactured, and the amount of wave (σ) of the belt protective layer and the Table 1 below shows the result of comparison of appearance defects.
The numerical values in Table 1 are expressed as an index when the prior art is set to 100.

As is apparent from Table 1, the tire according to the present invention has an extremely small amount of wave (σ) and no appearance defect. As a result, even when a tread groove corresponding to a circumferential groove was formed on the tread before vulcanization, it was found that if the ring member was not used, a misalignment between the protrusion of the mold and the tread would occur. Therefore, the effectiveness of the present invention was confirmed.

  As described above, according to the present invention, it is possible to manufacture a pneumatic tire in which the tire components inside the tread are not deformed during vulcanization even when the circumferential groove is wide or the groove depth is deep. Can do. Moreover, the method for manufacturing a pneumatic tire according to the present invention can be effectively used when manufacturing a tire that is regenerated by recapping, such as a radial tire for an aircraft.

It is a figure which shows one structural example of the green tire concerning the best form of this invention. It is a figure which shows the manufacturing method (attachment of a ring member) of the pneumatic tire concerning this best form. It is a figure which shows the structure of the ring member concerning this best form. It is a figure which shows the manufacturing method (setting at the time of vulcanization | cure) of the pneumatic tire concerning this best form. It is a figure which shows the manufacturing method of the conventional pneumatic tire. It is a figure which shows the other manufacturing method of the conventional pneumatic tire.

Explanation of symbols

10 Vulcanization mold, 10a Inner surface of vulcanization mold, 10c Recess (fitting part),
20 green tires (raw tires), 20M vulcanized tires, 21 carcass,
22a, 22b belt layer, 23 belt protective layer, 24 tread,
25 bead section, 25C bead core, 26 circumferential groove, 26K tread groove,
40 ring member, 40R ring piece, 41 protrusion, 42 substantially triangular convex part,
43 Rubber member.

Claims (4)

  After forming a green tire comprising a belt layer, a belt protective layer provided on the outer side of the belt layer in the tire radial direction, and a tread rubber provided on the outer side of the belt protective layer in the tire radial direction, the green tire is molded. In the method for manufacturing a pneumatic tire in which the raw tire is vulcanized using a vulcanization mold, a circumferential groove extending along the tire circumferential direction is formed on the surface of the tread rubber of the molded raw tire, and The ring portion having a protrusion that fits into the circumferential groove on the inner circumferential side is fitted into the circumferential groove, and the raw tire fitted with the ring member is placed in the vulcanization mold. A method for producing a pneumatic tire, characterized by being set and vulcanized.   Providing a convex portion or a concave portion on the outer peripheral side of the ring member, and providing a concave portion or a convex portion into which the convex portion or the concave portion is fitted in a portion facing the convex portion or the concave portion of the vulcanization mold, The pneumatic tire according to claim 1, wherein the green tire is vulcanized and molded after the convex portion or concave portion of the ring member is fitted into the concave portion or convex portion of the vulcanizing mold. Method.   The method of manufacturing a pneumatic tire according to claim 1 or 2, wherein the ring member is formed by connecting a plurality of ring pieces made of metal or alloy with a rubber member.   4. The metal or alloy constituting the ring piece is the same metal or alloy as the metal or alloy constituting at least the cavity side of the vulcanization mold. Method of manufacturing a pneumatic tire.

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