JP2007125786A - Method and mold for vulcanizing tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and surely carry out vulcanization in a tire production process. <P>SOLUTION: An uneven shape is formed by forming a plurality of ridges 11 in the circumferential direction in the side wall member 10 of a green tire 1, and exhaust channels 43 are formed radially to cross at right angles with the ridges 11 in a side mold 23 which contacts the side wall member 10 and carries out vulcanization. In the side mold 23, vent holes 44 are formed in a plurality of spots including exhaust channel 43 forming positions, and air between the side wall member 10 and the side mold 23 is discharged. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vulcanization mold used at the time of vulcanization of a tire, and a tire vulcanization method using the vulcanization mold.

  When manufacturing tires used in vehicles, etc., rubber components produced by extrusion molding are laminated on a molding drum to produce a cylindrical green tire, which is then vulcanized with a vulcanizer. Is cured. Here, it is known that when a component member is stacked on a forming drum, a convex portion or a concave portion is provided on a contact surface between the component members to reduce the amount of air remaining between the component members (for example, patents). Reference 1).

In the vulcanization process of the green tire, the green tire and the vulcanization mold are brought into close contact with each other, and then heat is applied to the vulcanization mold, and the green tire is heated and vulcanized through the vulcanization mold. The sulfur reaction is allowed to proceed. At this time, if vulcanization is performed with air remaining between the vulcanization mold and the green tire, vulcanization of the portion is insufficient. If the vulcanization is not performed sufficiently, insufficient strength, poor appearance, etc. occur, and it is necessary to prevent this. Conventional vulcanization molds are provided with vent holes that open on the contact surfaces that contact the components of the raw tire so that air between the raw tire and the vulcanization mold can be discharged. Yes (see, for example, Patent Document 2).
JP 2004-284165 A JP-A-3-247440

However, in the conventional vulcanization mold, air can be discharged when the location where the air pocket is generated coincides with the position where the vent hole is formed, but the air pool is generated at a location away from the vent hole. In such a case, air may remain without being discharged. On the other hand, if the number of vent holes is increased, it becomes easier to discharge air, but even in such a case, air may still remain. Further, when the number of vent holes is extremely large, the appearance is remarkably deteriorated, or the number of scraps increases due to an increase in spew scraps.
The present invention has been made in view of such circumstances, and its main purpose is to enable efficient and reliable vulcanization of raw tires.

The invention according to claim 1 of the present invention for solving the above-mentioned problems is a vulcanization mold having a contact surface in contact with an unvulcanized tire, the outer surface of the contact surface and a component of the unvulcanized tire. An exhaust portion that exhausts air between the surface and the exhaust portion extends across a plurality of protrusions or grooves formed on an outer surface of the component of the unvulcanized tire, A tire vulcanization mold having an exhaust guide that opens to the contact surface and allows air to flow in a predetermined direction.
In this tire vulcanization mold, when a plurality of ridges or grooves formed on the surface of the constituent members constituting the unvulcanized tire come into contact with the contact surface of the vulcanization mold, the number of ridges or grooves A plurality of gaps are formed accordingly. The air in this gap is discharged through the exhaust guide. Since the exhaust guide extends so as to intersect the plurality of protrusions or grooves, the air in the plurality of gaps formed by the plurality of protrusions or grooves flows along the length direction of the protrusions or grooves. Then, it is discharged so as to be collected in the exhaust guide. When the component member is further pressed against the vulcanization mold while discharging air, vulcanization can be performed with the component member and the vulcanization mold in close contact with each other.

According to a second aspect of the present invention, in the tire vulcanization mold according to the first aspect, the exhaust guide includes an exhaust groove having a concave contact surface, and the exhaust groove communicates with the exhaust groove. The exhaust part is formed of a vent hole that performs the above-described operation.
In the tire vulcanizing mold, the air in the gap formed on the contact surface between the unvulcanized tire and the vulcanizing mold flows into the vent hole through the exhaust guide and is exhausted from the vent hole.

The invention according to claim 3 is the tire vulcanization mold according to claim 2, wherein the exhaust groove is orthogonal to the ridge or groove projecting in the circumferential direction of the component member. The contact surface is radially formed.
In this tire vulcanizing mold, when the gap between the ridge or groove and the position of the vent hole are misaligned, the air is led to the exhaust groove through the gap between the ridge or groove and communicated with the exhaust groove. Exhausted from the vent hole. Since the exhaust grooves are provided radially so as to be orthogonal to the ridges or grooves, the exhaust grooves can be communicated with the gaps formed by all the ridges or grooves with a small number.

The invention according to claim 4 is a tire vulcanizing method for vulcanizing an unvulcanized tire, wherein a plurality of protrusions or grooves formed on an outer surface of a constituent member of the unvulcanized tire are vulcanized gold. A step of pressing against the contact surface of the mold, and air in a gap formed between the plurality of protrusions or grooves of the component member and the contact surface of the vulcanizing mold to each of the protrusions or grooves And a step of sucking along the tire.
In this method of vulcanizing a tire, when the air in the gap formed along the ridge or groove is exhausted when the structural member is pressed against the vulcanizing mold, the air first enters the ridge or groove. Aspirated along.

According to a fifth aspect of the present invention, in the tire vulcanizing method according to the fourth aspect, the sucking step collects air flowing along the ridges or grooves through an exhaust groove having the contact surface recessed. And discharging from the vent hole communicated with the exhaust groove.
In this tire vulcanizing method, the air sucked along the ridges or grooves changes the flow direction in the direction intersecting the ridges or grooves by the exhaust groove on the vulcanizing mold side, thereby a plurality of gaps. The air is collected and exhausted.

The invention according to claim 6 is the method of vulcanizing a tire according to claim 4 or claim 5, wherein the component member is further pressed against the heated mold for vulcanization, and the surface of the component member is thermally fluidized. And the step of eliminating the ridges or grooves.
In this tire vulcanization method, the protrusions or grooves on the surface of the constituent member of the green tire are eliminated by heat flow, and the surface of the constituent member and the contact surface are brought into close contact with each other.

  According to the present invention, since the air in the gap formed between the concavo-convex shape by the protrusion or groove on the green tire side and the contact surface on the vulcanizing mold side is exhausted through the exhaust guide, No air remains between the contact surface and the contact surface. Therefore, the raw tire can be reliably vulcanized.

Embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2 show a configuration of a raw tire (unvulcanized tire) before vulcanization in the present embodiment. The raw tire 1 has a pair of bead portions 2 that are fitted to a rim of a wheel (not shown), and a sidewall portion 3 extends from the bead portion 2. The pair of sidewall portions 3 are connected by a tread portion 5 that directly contacts the road surface after passing through the shoulder portion 4. The bead portion 2 has a configuration in which a ply 7 sandwiching a carcass is folded to wrap a bead wire 6 and a bead filler 8 is sandwiched. The sidewall portion 3 to the tread portion 5 are formed by stacking these constituent members using unvulcanized rubber, a carcass and a belt as constituent members. The outermost layer of the sidewall portion 3 includes a sidewall member 10 that is a constituent member made of unvulcanized rubber, and the surface of the sidewall member 10 has an uneven shape.

  The uneven shape of the sidewall member 10 is formed by a large number of ridges 11 (projections). The ridges 11 are projected at equal intervals from the bead portion 2 to the shoulder portion 4. Furthermore, as shown in FIG. 1, a large number of ridges 11 are formed concentrically in the circumferential direction of the raw tire 1. As shown in FIG. 2, each ridge 11 has a triangular shape that decreases in width toward the outside in a cross section orthogonal to the circumferential direction. Note that the ridge 11 may have a cross-sectional shape, a rectangular shape, or a curved surface shape. The arrangement of the ridges 11 is not equal, and the number of ridges 11 is not limited to that shown in the figure. The uneven shape of the sidewall member 10 may be formed by a groove, or may be formed by a combination of a protrusion and a groove.

  FIG. 3 shows a schematic configuration of a vulcanizing device used in the vulcanizing process of the green tire 1. In the vulcanizer 20, the lower side mold 23 is fixed upward on the upper surface of the lower base 21 via the lower platen 22. The lower platen 22 has a flow path (not shown) through which a high-temperature and high-pressure heating medium flows. The lower side mold 23 is a vulcanization mold that mainly molds the sidewall member 10 during vulcanization. A center post 24 is fixed vertically upward at the center of the lower side mold 23. A pair of upper and lower clamp rings 25, 26 are fixed to the center post 24, and the clamp rings 25, 26 are connected by a vulcanizing bladder 27 having flexibility. FIG. 3 shows a state in which the raw tire 10 is arranged so as to surround the vulcanization bladder 27.

  An upper base 30 is provided above the lower base 21. The upper base 30 can be moved up and down with respect to the lower base 21 along the guide posts 31. An upper side mold 33 is fixed downward on the lower surface of the upper base 30 via an upper platen 32. The upper platen 32 has a flow path (not shown) through which a high-temperature and high-pressure heating medium flows. The upper side mold 33 is a vulcanization mold that mainly molds the sidewall member 10 during vulcanization. The upper side mold 33 is fixed to a position facing the lower side mold 23 in the vertical direction.

  Further, an outer ring 34 is fixed to the upper base 30 so as to surround the outer periphery of the upper platen 32. The outer ring 34 projects downward from the upper side mold 33 and has an inclined surface 34A that is inclined so as to open downward on the inner periphery thereof. A sector mold 36 is disposed on the inclined surface 34 </ b> A via a side platen 35. The side platen 35 is attached to the outer ring 34 so as to be slidable up and down along the inclined surface 34A. Inside the side platen 35, a flow path (not shown) through which a high-temperature and high-pressure heat medium flows is formed. The sector mold 36 is a vulcanization mold that mainly molds the tread portion 5 during vulcanization, and is divided into a plurality along the circumferential direction of the raw tire 1. In the figure, two sector molds 36 are shown. For example, nine sector molds 36 are arranged at equal intervals, and each of them has a curved surface shape that matches the shape of the tread portion 5 after vulcanization. Have.

Here, the configuration of the upper side mold 33 will be described with reference to FIGS. 3 and 4.
The upper side mold 33 has an annular shape with an opening 41 formed in the center. The opening 41 has a diameter and a depth that can receive the clamp ring 26. On the lower surface (contact surface 33A) against which the raw tire 1 is pressed, the inner edge portion 42 that forms the periphery of the opening 41 protrudes downward. The outer edge of the inner edge portion 42 is gently inclined toward the radially outer side of the upper side mold 33. The outer edge side of the upper side mold 33 is substantially flat.

The upper side mold 33 is provided with an exhaust portion that exhausts air on the contact surface 33A side. The exhaust part includes an exhaust groove 43 that is a recess formed in the contact surface 33 </ b> A, and a vent hole 44 that opens to the contact surface 33 </ b> A and penetrates the upper side mold 33.
The exhaust grooves 43 are exhaust guides that are provided in a plurality radially from the opening 41 and allow air to flow in a predetermined direction. Each exhaust groove 43 extends linearly from the outer edge of the inner edge portion 42 protruding downward to the outer surface of the upper side mold 33. The width of the exhaust groove 43 in the circumferential direction is a size that does not leave an unvulcanized portion in the sidewall member 10 in the vulcanization process described later. A plurality of vent holes 44 are formed radially with the opening 41 as the center, and three vent holes 44 are arranged at substantially equal intervals in the radial direction from the outer edge of the inner edge portion 42 to the outer peripheral surface. Some of the vent holes 44 are formed at positions corresponding to the positions where the exhaust grooves 43 are formed. The remaining vent holes 44 are formed in a substantially middle portion between two exhaust grooves 43 adjacent in the circumferential direction. The diameter of each vent hole 44 is larger than the circumferential width of the exhaust groove 43. Each vent hole 44 penetrates the upper side mold 33 and is connected to an exhaust pump (not shown).

  Since the lower side mold 23 shown in FIG. 3 has the same configuration as the upper side mold 33, detailed description thereof is omitted. A plurality of exhaust grooves 43 (exhaust guides), which are exhaust portions of the lower side mold 23, are formed radially on the upper surface (contact surface 23A) of the lower side mold 23. A large number of vent holes 44 are opened in the contact surface 23 </ b> A of the lower side mold 23.

Next, the operation of this embodiment will be described.
First, in order to manufacture the sidewall member 10, a base 50 as shown in FIGS. 5 to 7 is used. The base 50 is used by being fixed to the discharge-side head 52 of the extruder 51, and the cross-sectional shape of the elongated opening 53 is formed in accordance with the cross-sectional shape of the sidewall member 10. That is, the opening 53 has a high opening height on the one end 53A side in the length direction and a small opening height on the other end 53B side. Further, a plurality of projections 54 are formed at the upper edge of the opening 53 at equal intervals along the length direction of the opening 53 except for the vicinity of the one end portion 53A and the other end portion 53B. , Having an uneven shape. The protrusion 54 protrudes on the outlet side in the pushing direction indicated by an arrow in FIG. The shape formed by the ridge line of the protrusion 54 is equal to the outer shape of the ridge 11 of the sidewall member 10, and the arrangement interval of the protrusions 54 is equal to the formation interval of the ridge 11.

  When manufacturing the side wall member 10 using such a nozzle | cap | die 50, a rubber composition is thrown into the extruder 51 shown in FIG. 7 from a hopper not shown. The extruder 51 rotates an internal screw to extrude the rubber composition from the die 50 attached to the head 52. The rubber composition follows the shape of the opening 53 of the base 50, and is extruded while being thickened on the one end 53A side and relatively thin on the other end 53B side. Furthermore, immediately before being extruded from the base 50, the projections 54 form an uneven shape parallel to the extrusion direction. The protruding portion of the concavo-convex shape becomes the ridge 11 of the sidewall member 10. The extruded rubber molded product is laminated as a side wall member 10, that is, a constituent member of the green tire 1, so that the other end side is continuous with the shoulder portion 4 so that the one end side is wound around the bead portion 2.

  When the raw tire 1 is manufactured by laminating the side wall member 10 on other constituent members, the raw tire 1 is mounted on the vulcanizing device 30 shown in FIG. The raw tire 1 is passed through the center post 24 and positioned and placed on the lower side mold 23. When the upper base 30 is lowered, the contact surface 33 </ b> A of the upper side mold 33 comes into contact with the upper side wall member 10 of the green tire 1. At the same time, the plurality of sector molds 36 ascend along the inclined surfaces 34 </ b> A of the outer ring 34, move so as to close toward the raw tire 1, and surround the tread portion 5. An exhaust pump (not shown) is operated to exhaust air from the vent hole 44, and a heating medium is supplied to each of the flow paths in the platens 22, 32, and 35 and the inside of the vulcanization bladder 27. As a result, the molds 23, 33 and 36 are heated through the platens 22, 32 and 35. The vulcanizing bladder 27 swells and presses the raw tire 1 and presses the outer surface of the raw tire 1 against the molds 22, 32 and 36.

  At this time, as shown in FIGS. 8 and 9, when the ridge 11 comes into contact with the respective side molds 23, 33, an annular gap 12 is formed by the ridge 11 and the side molds 23, 33. The air in the gap 12 flows along the gap 12 where the formation position of the vent hole 44 coincides with the position of the gap 12, and is discharged out of the side molds 23 and 33 through the vent hole 44. Is done. In a place where the formation position of the vent hole 44 and the formation position of the gap 12 do not coincide, the air in the gap 12 flows along the gap 12 and then flows into the exhaust groove 43 formed in the radial direction perpendicular to the ridge 11. To do. Further, the gas flows in the exhaust gas groove 43 in the radial direction so as to be guided by the exhaust gas groove 43, and is discharged out of the side molds 23 and 33 from the vent hole 44 formed in the gas exhaust groove 43. Since the exhaust groove 43 is formed so as to straddle the plurality of gaps 12 (the plurality of ridges 11) in the radial direction, the air flowing through the plurality of gaps 12 is collected in the exhaust groove 43 and exhausted.

  Further, when the vulcanization bladder 27 is inflated while discharging air, the raw tire 1 is further pressed against the side molds 23 and 33. As shown in FIG. 10, the ridge 11 disappears due to the heat flow of the rubber, and the sidewall member 10 is in close contact with the side molds 23 and 33 without a gap. In the process in which the ridge 11 disappears, the gap 12 gradually decreases. However, since the air in the gap 12 is exhausted from the vent hole 44, no air pool is generated. When the outer surface of the green tire 1 is in close contact with the molds 23, 33, and 36, the vulcanization of the green tire 1 further proceeds by heat conduction. Heat is also transmitted to the sidewall member 10 facing the exhaust groove 43 and vulcanization proceeds. When the vulcanization is completed, the molds 23, 33 and 36 are opened and the vulcanized tire is taken out.

According to this embodiment, a plurality of ridges 11 are provided in the circumferential direction on the side wall member 10 side of the raw tire 1, and exhaust grooves 43 and vent holes 44 extending in the radial direction are provided on the side molds 23, 33 side, and vulcanized. Since the air between the ridges 11 is sometimes discharged out of the side molds 23 and 33 through the exhaust groove 43 and the vent hole 44, the air does not remain between the raw tire 1 and the side molds 23 and 33. This prevents poor vulcanization due to air accumulation and poor appearance on the tire surface.
Since the exhaust grooves 43 are formed so as to intersect with the plurality of ridges 11, when the air is exhausted in cooperation with the ridges 11 and the exhaust grooves 43, the air in the plurality of gaps 12 is changed while changing the air flow direction. Can be discharged while being collected in the exhaust groove 43. For this reason, it is possible to reliably exhaust a wider range of air than in the past while suppressing the number of vent holes 44 on the side molds 23 and 33 side. In particular, since the exhaust groove 43 is orthogonal to the ridge 11, it is possible to efficiently exhaust the air in the numerous gaps 12. Since the ridge 11 on the tire side disappears due to heat flow during vulcanization, the appearance of the tire after vulcanization does not deteriorate.

The present invention can be widely applied without being limited to the above-described embodiment.
For example, when a plurality of ridges 11 of the raw tire 11 are formed radially in the radial direction, a plurality of exhaust grooves 43 of the side molds 23, 33 are formed annularly in the circumferential direction so as to intersect the plurality of ridges 11. .
The exhaust groove 43 may have any shape and arrangement as long as all the gaps 12 formed by the ridge 11 can communicate with at least one exhaust groove 43. For example, they may intersect at a predetermined angle without being orthogonal to the ridge 11, or may be divided into a plurality of parts in the radial direction or the circumferential direction. The vent hole 44 may be formed only in the exhaust groove 43. On the other hand, without forming the vent hole 44 in the exhaust groove 43, the exhaust groove 43 may be configured to exhaust air from an opening formed in the outer periphery of the side molds 23 and 33.
In the vent hole 44, the formation positions of two vent holes 44 adjacent in the circumferential direction may be different in the radial direction. Since the two adjacent vent holes 44 communicate with the different gaps 12, the air can be quickly exhausted.

  The vulcanization mold may have a sector type configuration in which a vulcanization mold for vulcanizing the sidewall member 10 is divided into a plurality of parts in the circumferential direction. In this case, a plurality of exhaust grooves 43 and vent holes 44 are formed in a vulcanization mold corresponding to the sector mold 36 of the vulcanizer 30 shown in FIG. The exhaust groove 43 is provided in a direction substantially orthogonal (or intersects) with the ridge 11 of the sidewall member 10 of the raw tire 1.

The exhaust guide may be a slit that penetrates the side molds 23 and 33. Since the slit also serves as the vent hole 44, the exhaust portion is composed of only the slit or the vent hole 44 formed at a place other than the slit and the slit.
The protrusion 54 shown in FIG. 6 may be formed over the entire length of the opening 53 in the extrusion direction.

It is a figure showing the schematic structure of the green tire concerning the embodiment of the present invention. It is sectional drawing along the AA line of FIG. 1, Comprising: It is the schematic which shows the cross-sectional shape of a green tire. It is a schematic block diagram which shows an example of a vulcanizer. It is a B arrow line view of Drawing 3, and is a figure showing the composition of a side mold. It is a figure which shows the nozzle | cap | die of the extruder used when shape | molding a sidewall member. It is sectional drawing along CC line of FIG. 5, Comprising: It is a figure which shows the formation position of protrusion. It is a figure explaining the process of shape | molding a sidewall member with an extruder. It is a figure explaining the process in which the air between a side mold and a side wall member is discharged | emitted in a vulcanization | cure process. FIG. 9 is a cross-sectional view taken along the line DD of FIG. 8, illustrating a process in which air is discharged from the exhaust groove through the vent hole. FIG. 10 is a diagram in which the ridge is eliminated by further pressing the sidewall member against the side mold from FIG. 9.

Explanation of symbols

1 Raw tire (unvulcanized tire)
10 Side wall member (component)
11 Ridge 12 Clearance 23 Lower side mold (vulcanizing mold)
23A, 33A Contact surface 33 Upper side mold (vulcanizing mold)
43 Exhaust groove (exhaust section, exhaust guide)
44 Vent hole (exhaust part)

Claims (6)

  A mold for vulcanization having a contact surface in contact with an unvulcanized tire, the exhaust mold configured to exhaust air between the contact surface and an outer surface of a component member of the unvulcanized tire, The exhaust portion extends through a plurality of protrusions or grooves formed on the outer surface of the component member of the unvulcanized tire, and has an exhaust guide that opens to the contact surface and allows air to flow in a predetermined direction. A mold for vulcanizing a tire, comprising:   2. The tire according to claim 1, wherein the exhaust guide includes an exhaust groove having a concave contact surface, and the exhaust portion is configured by the exhaust groove and a vent hole communicating with the exhaust groove. Mold for vulcanization.   3. The tire according to claim 2, wherein the exhaust groove is formed radially on the contact surface so as to be orthogonal to the ridge or groove projecting in a circumferential direction of the component member. Mold for vulcanization.   A method of vulcanizing a tire for vulcanizing an unvulcanized tire, the step of pressing a plurality of protrusions or grooves formed on an outer surface of a constituent member of the unvulcanized tire against a contact surface of a vulcanization mold; A step of sucking air in a gap formed between the plurality of protrusions or grooves of the constituent member and the contact surface of the vulcanizing mold along the protrusions or grooves, respectively. A tire vulcanizing method.   5. The sucking step collects air flowing along the ridge or groove through an exhaust groove having a concave contact surface and discharges it from a vent hole communicated with the exhaust groove. The method for vulcanizing a tire according to 1. 6. The method according to claim 4, further comprising the step of further pressing the component member against the heated mold for vulcanization to cause the surface of the component member to thermally flow to extinguish the protrusions or grooves. The method for vulcanizing a tire according to 1.

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