JP2014156043A - Mold for tire vulcanization bladder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for a tire vulcanization bladder which prevents flashing of a crude rubber in the mold mating surface in molding of a tire vulcanization bladder, reduces the used amount of the raw material for the tire vulcanization bladder and the number of working steps and improves the production efficiency to reduce costs.SOLUTION: A mold 1 for a tire vulcanization bladder 10 includes an outer mold 2 consisting of an upper mold 4 and a lower mold 5, divided vertically, and a middle mold 3 arranged in the outer mold 2. In an inner wall 4a of the upper mold 4 and an inner wall 5a of the lower mold 5, there are provided convex parts 4d and 5d along the mating surfaces 4b and 5b of the upper mold 4 and the lower mold 5, respectively, in the circumferential direction.

Description

  The present invention relates to a mold for a tire vulcanization bladder for producing a tire vulcanization bladder used in vulcanization molding of a raw tire.

  As shown in FIG. 12, the conventional mold 30 of the tire vulcanization bladder is divided into an upper mold 33 and a lower mold 34 which are divided into upper and lower parts, and an intermediate mold disposed in the outer mold 31. 32. The upper die 33 is moved up and down by a cylinder (not shown). A predetermined amount of raw rubber 36 is placed on the mating surface 34a of the lower die 34, and the upper die 33 is moved downward by the cylinder to move the upper die 33. By compressing the raw rubber with the mating surface 33a and the mating surface 34a of the lower die 34, a tire vulcanizing bladder having a predetermined shape is compression molded. Alternatively, a tire vulcanization bladder having a predetermined shape is formed by injection molding in which a predetermined amount of raw rubber 36 is injected into a cavity 37 constituted by the outer mold 31 and the intermediate mold 32. The tire vulcanization bladder formed in a predetermined shape is then heated in the mold 30 for a predetermined time to be vulcanized and manufactured.

  However, the tire vulcanizing bladder 35 manufactured using such a mold 30 has a structure in which the raw rubber 36 is compressed by the mold 30 or injected into the cavity 37 and molded. 13 is formed between the mating surface 33a and the mating surface 34a of the lower mold 34. After the vulcanization molding, the process of removing this protrusion 38 by buffing is required. It was. In addition, the raw rubber protrusion 38 increased the necessary amount of raw rubber and increased raw material costs.

  In order to eliminate this inconvenience, as shown in FIG. 14, the mating surface 43a of the upper mold 43 and the mating surface 44a of the lower mold 44 are parallel, and the gap between the mating surface 43a and the mating surface 44a is as small as possible. Some manufacture a tire vulcanizing bladder 45 using a mold 40 (see Patent Document 1). However, even if the tire vulcanizing bladder 45 is manufactured using such a mold 40, the raw rubber 46 is not bonded to the mating surface 43a of the mold 40 during compression molding or injection molding as shown in FIG. , 44a, and a protrusion 47 is formed over the circumferential direction of the tire vulcanizing bladder 45.

  The raw tire vulcanization molding using the tire bladder 45 means that the unvulcanized tire is stored in the tire vulcanization mold and the tire vulcanization bladder 45 is disposed inside the unvulcanized tire. Then, a heat medium such as high-temperature and high-pressure steam or hot water is sent into the tire vulcanizing bladder 45 and the tire vulcanizing bladder 45 expands, and the tire vulcanizing bladder 45 causes the unvulcanized tire to be used for tire vulcanization. The green tire is pressed against a mold and heated for a predetermined time to be vulcanized.

  When the raw tire is vulcanized using the tire vulcanization bladder 45 in which the protrusion 47 is formed in the circumferential direction as described above, the protrusion 47 of the tire vulcanization bladder 45 is transferred to the inner peripheral surface of the tire. As a result, a recess is formed. Since it is difficult to distinguish between a tire with a recess formed on the inner peripheral surface of such a tire and a tire manufactured with a defective product with a scratched bladder, The tires vulcanized and manufactured using the vulcanizing bladder 45 are all defective products, and the manufacturing costs of the tires have increased.

Japanese Patent Laid-Open No. 7-24835

  The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to prevent the raw rubber from protruding along the mating surface of the upper and lower halves when the tire vulcanization bladder is molded. Tire vulcanization bladders that can reduce the amount of raw rubber used as a raw material for tire vulcanization bladders, eliminate the process of removing protrusions, improve production efficiency, and reduce production costs Is to provide the mold.

  In order to solve the above-mentioned object, the invention described in claim 1 is a mold comprising an outer mold composed of an upper mold and a lower mold divided into two parts, and a middle mold disposed in the outer mold. Convex portions are provided on the inner walls of the upper mold and the lower mold along the circumferential direction along the mating surfaces of the upper mold and the lower mold.

  According to a second aspect of the present invention, in the die for a tire vulcanizing bladder according to the first aspect, the convex portion has a wedge-shaped longitudinal cross-sectional shape.

  A third aspect of the invention is characterized in that the tire vulcanization mold according to the first or second aspect is used for compression molding or injection molding.

  According to the first aspect of the present invention, a tire vulcanization bladder is provided by providing convex portions along the circumferential direction of the inner wall of the upper mold and the inner wall of the lower mold along the mating surface of the upper mold and the lower mold. It is possible to prevent the raw rubber from sticking out along the mating surfaces of the molds, reduce raw materials such as raw rubber used for manufacturing the tire vulcanization bladder, and reduce the manufacturing cost.

  Furthermore, by preventing the tire vulcanization bladder from protruding along the mating surface of the mold, it is possible to eliminate the work of removing the vulcanized tire vulcanization bladder, and the tire vulcanization bladder. Manufacturing work steps can be reduced, manufacturing efficiency can be improved, and manufacturing costs can be reduced.

  Furthermore, when a tire is vulcanized and molded using such a tire vulcanizing bladder manufactured by such a mold, a concave portion is formed in the circumferential direction on the outer periphery of the tire vulcanizing bladder. , A convex part is formed on the inner wall of the tire in the circumferential direction, and it becomes easy to distinguish from a tire manufactured by a defective product having a scratched bladder, and the number of tires judged to be defective It is possible to reduce the manufacturing cost.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the vertical cross-sectional shape of the convex portion of the mold of the tire vulcanization bladder is a wedge shape, whereby the mating surface of the upper die The gap between the mating surfaces of the lower mold and the mold can be eliminated to further prevent the raw rubber from protruding.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, it is possible to prevent the raw rubber from protruding from the tire vulcanization bladder used for compression molding or injection molding.

It is a longitudinal cross-sectional view of the metal mold | die of the tire vulcanization bladder and the diamond vulcanization bladder in one Example of this invention. It is a principal part expanded longitudinal cross-sectional view of FIG. It is the longitudinal cross-sectional view which showed the manufacturing method of the bladder for tire vulcanization | cure using the metal mold | die of a present Example. It is the longitudinal cross-sectional view which showed the manufacturing method of the bladder for tire vulcanization | cure using the metal mold | die of a present Example. It is the longitudinal cross-sectional view which showed the manufacturing method of the bladder for tire vulcanization | cure using the metal mold | die of a present Example. It is the longitudinal cross-sectional view which showed the manufacturing method of the bladder for tire vulcanization | cure using the metal mold | die of a present Example. It is the principal part longitudinal cross-sectional view which showed the manufacturing method of the bladder for tire vulcanization | cure using the metal mold | die of a present Example. It is a perspective view of the bladder for tire vulcanization manufactured using the metallic mold of this example. It is a longitudinal cross-sectional view of the vulcanization molding state of the tire using the tire vulcanization bladder manufactured using the metal mold | die of a present Example. FIG. 10 is an enlarged vertical sectional view of a main part of FIG. 9. It is a principal part expansion longitudinal cross-sectional view of the tire manufactured using the bladder for tire vulcanization manufactured with the metal mold | die of a present Example. It is the longitudinal cross-sectional view which illustrated the conventional bladder for tire vulcanization, and its metal mold | die. It is a principal part expanded longitudinal cross-sectional view of FIG. It is the longitudinal cross-sectional view which illustrated another conventional tire vulcanization bladder and its metal mold | die. It is a principal part expanded longitudinal cross-sectional view of FIG.

  An embodiment according to the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the mold 1 of the tire vulcanizing bladder according to the present embodiment includes an outer mold 2 and a middle mold 3 disposed in the outer mold 2. The outer mold 2 is composed of an upper mold 4 and a lower mold 5 divided into upper and lower molds, and the upper mold 4 is moved in the vertical direction by a cylinder (not shown).

  The mating surface 4b of the upper mold 4 and the mating surface 5b of the lower mold 5 are substantially horizontal planes perpendicular to the vertical direction in which the upper mold 4 moves, and are formed substantially in parallel. When the lower mold 5 is moved downward by the cylinder and fitted to the lower mold 5, a gap is not formed between the mating surface 4 b of the upper mold 4 and the mating surface 5 b of the lower mold 5.

  The middle mold 3 is composed of an upper middle mold 6 and a lower middle mold 7, and the lower middle mold 7 is fitted in a recess 5 c formed at the lower center of the lower mold 5, and is formed at the center of the lower surface of the upper middle mold 6. The recessed portion 6b is fitted into the lower middle mold 7 for positioning.

  As shown in FIG. 2, a convex portion 4d is formed on the inner wall surface 4a of the upper die 4 along the end portion 4c of the mating surface 4b of the upper die 4 along the circumferential direction. The vertical cross-sectional shape of the convex portion 4d cut along the line has a wedge shape with the end portion 4c of the mating surface 4b as a vertex.

  Further, on the inner wall surface 5 a of the lower mold 5, similarly to the upper mold 4, a convex portion 5 d is formed along the end portion 5 c of the mating surface 5 b of the lower mold 5 along the circumferential direction. The vertical cross-sectional shape of the convex portion 5d cut along the line has a wedge shape with the end portion 5c of the mating surface 5b as a vertex.

  Next, a method of manufacturing the tire vulcanizing bladder 10 using the mold 1 will be described with reference to FIGS.

  As shown in FIG. 3, the lower middle mold 7 is set so as to be fitted in a recess 5 c formed at the lower center of the lower mold 5, and a tire vulcanizing bladder 10 is disposed below the inner wall 5 a of the lower mold 5. The amount of charging material 9 that is approximately half the amount of raw rubber necessary for production is placed. As raw rubber, butyl rubber or the like having low gas permeability is used.

  Thereafter, as shown in FIG. 4, the lower middle wall surface 6 a of the upper middle mold 6 is arranged so as to be placed on the prepared material, and as shown in FIG. 5, the upper middle mold 6 is positioned above the outer wall surface 6 a. In addition, the remaining amount of the charging material 9 excluding the raw rubber placed on the lower mold 5 from the amount of raw rubber necessary for manufacturing the tire vulcanizing bladder 10 is placed.

  Thereafter, as shown in FIG. 6, when the upper mold 4 is moved downward by a cylinder (not shown) and overlapped on the lower mold 5 side, the charging material 9 charged between the middle mold 3 and the outer mold 2 is placed. Is compressed by the outer wall 6a of the upper middle mold 6 and the inner wall 4a of the upper mold 4, and by the outer wall 7a of the lower middle mold 7 and the inner wall 5a of the lower mold 5, and the upper mold 4, the lower mold 5, the upper middle mold 6 and the lower middle mold 7 are compressed. The raw rubber charging material 9 flows into the cavity 8 constituted by the tire vulcanizing bladder 10 in a predetermined shape.

  As shown in FIG. 2, a convex portion 4d is provided at the end portion 4c of the mating surface 4b of the upper mold 4, and a convex portion 5d is provided at the end portion 5c of the mating surface 5b of the lower die 5. Since the cross-sectional shapes of 4d and 5d are formed in a wedge shape, the raw rubber charging material 9 flows along the surfaces of the convex portions 4d and 5d as shown in FIG. The raw rubber charging material 9 is less likely to flow between the mating surface 4b and the mating surface 5b of the lower mold 5, and the mating surface 4b of the upper mold 4 and the lower mold are molded when the tire vulcanizing bladder 10 is molded. The protrusion of the raw rubber along the 5 mating surface 5b is less likely to occur.

  Further, the convex portion 4d is formed on the end portion 4c of the mating surface 4b of the upper die 4 and the convex portion 5d is formed on the end portion 5c of the mating surface 5b of the lower die 5, so that the tire vulcanizing bladder 10 is provided. On the outer peripheral surface 10c, a concave portion 10a is formed in a circumferential shape along the mating surfaces 4b and 5b.

  Thereafter, the tire vulcanizing bladder 10 is heated and vulcanized for a predetermined time in a state of being compressed in the mold 1, and as shown in FIG. A tire barrel vulcanizing bladder 10 having a substantially barrel shape in which a concave portion 10 is formed along the circumference at the center in the vertical direction of the outer peripheral surface 10c is manufactured.

  Next, vulcanization of the raw tire 24 manufactured using the tire vulcanization bladder 10 as shown in FIG. 9 will be described. The raw tire 24 includes an inner liner 11, a carcass ply 12, a bead 13, a bead filler 14, a chafer 15, a belt 16, a tread 17, a sidewall 18, and the like.

  Flange portions 10b provided at both ends of the tire vulcanizing bladder 10 are supported by the ring holder 19, and the tire vulcanizing bladder 10 is inserted into the raw tire 24 and vertically The upper mold 21 and the lower mold 22 of the divided tire vulcanizing mold 20 are brought into contact with each other. Thereafter, a heat medium such as high-temperature and high-pressure steam or hot water is sent into the tire vulcanization bladder 10 to inflate the tire vulcanization bladder 10, and the raw tire 24 is tire vulcanized by the tire vulcanization bladder 10. Pressed against the mold 20.

  At this time, the inner wall 11b of the inner liner 11 arranged on the innermost side of the raw tire 24 is strongly pressed by the tire vulcanizing bladder 10, so that the inner liner before vulcanization is obtained as shown in FIG. 11 raw rubber flows into the concave portion 10a of the tire vulcanizing bladder 10, and the shape of the concave portion 10a is transferred to the inner wall 11b of the inner liner 11, so that the convex portion 11a is formed on the inner surface of the tire in the circumferential direction.

  The raw tire 24 is vulcanized and molded by being heated in such a state for a predetermined time, and as shown in FIG. 11, a tire 23 having a convex portion 23a formed on the inner wall 2b in the circumferential direction is manufactured. .

  When this example is applied to a tire vulcanization bladder used for a tire having a tire size of 17 inches, the amount of raw rubber used per tire vulcanization bladder is 7.20 kg before application. On the other hand, in this example, it was 6.95 kg, and it became possible to reduce the amount of raw rubber used by 250 g per bottle.

  As described above, in this embodiment, the upper mold 4 and the lower mold 5 protrude in the circumferential direction along the end portions 4c and 5c of the mating surfaces 4b and 5b of the upper mold 4 and the lower mold 5. The portions 4d and 5d are provided, the cross-sectional shape is formed in a wedge shape, and the mating surfaces 4a and 5b are formed substantially in parallel. When the upper die and the lower die are combined, the mating surfaces 4b and 5b Since the gap is formed so that there is no gap between them, the raw rubber charging material 9 flows along the surfaces of the convex portions 4d and 5d, and the raw rubber is less likely to flow between the mating surfaces 4b and 5b. Further, it is possible to prevent the raw rubber from sticking out of the prepared material 9 along the mating surfaces 4b and 5b of the mold 1 of the tire vulcanizing bladder 10.

  Further, by preventing the raw rubber from protruding, the amount of raw rubber of the preparation material 9 used for manufacturing the tire vulcanizing bladder 10 can be reduced, and the manufacturing cost can be reduced.

  Furthermore, by preventing the tire vulcanization bladder 10 from protruding in the circumferential direction, it is possible to eliminate the buffing step of removing the protrusion along the circumferential direction of the vulcanized tire vulcanization bladder 10, and tire vulcanization. The manufacturing process of the sulfur bladder 10 can be reduced, the manufacturing efficiency can be improved, and the manufacturing cost can be reduced.

  Furthermore, when the tire 23 is manufactured by vulcanizing and molding the raw tire 24 using such a tire vulcanizing bladder 10, a recess 10a is formed on the outer periphery of the vulcanizing bladder 10 in the circumferential direction. Therefore, a convex portion 23a is formed on the inner wall of the tire 23 in the circumferential direction, so that it is possible to distinguish the defective product from the tire manufactured by the tire vulcanizing bladder, which is damaged, and is judged as a defective product. The number of tires to be used can be reduced, and the manufacturing cost can be reduced.

  The mold 1 of the tire vulcanization bladder 10 described above is used for compression molding, but is an injection mold for injecting raw rubber 7 into a cavity 8 formed between the outer mold 2 and the middle mold 3. You may apply to.

  DESCRIPTION OF SYMBOLS 1 ... Mold, 2 ... Outer type, 3 ... Medium type, 4 ... Upper type, 4a ... Inner wall, 4b ... Mating surface, 4c ... End part, 4d ... Convex part, 5 ... Lower type | mold, 5a ... Inner wall, 5b ... Mating Surface, 5c ... End, 5d ... Projection, 6 ... Upper middle mold, 6a ... Outer wall, 7 ... Lower middle mold, 7a ... Outer wall, 8 ... Cavity, 9 ... Feeding material, 10 ... Tire vulcanizing bladder, 11 ... Inner Liner, 12 ... carcass ply, 13 ... bead, 14 ... bead filler, 15 ... chafer, 16 ... belt, 17 ... tread, 18 ... side wall, 19 ... ring holder, 20 ... mold for tire molding, 21 ... upper mold, 22 ... Lower mold, 23 ... Tire, 24 ... Raw tire.

Claims (3)

In a mold comprising an outer mold composed of an upper mold and a lower mold divided into two parts, and a middle mold disposed in the outer mold,
A mold for a tire vulcanization bladder, wherein a convex portion is provided on the inner wall of the upper mold and the inner wall of the lower mold along a circumferential direction along a mating surface of the upper mold and the lower mold.   2. The mold for a tire vulcanizing bladder according to claim 1, wherein the convex portion has a wedge shape in vertical cross section.   The mold for a tire vulcanizing bladder according to claim 1 or 2, which is used for compression molding or injection molding.

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