JP2016037034A - Mold for forming bladder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bladder forming mold that suppresses generation of a burr on a bladder after vulcanization molding to eliminate the possibility of reducing productivity.SOLUTION: A bladder forming mold pressing a slab to vulcanize and mold a bladder comprises an upper mold and a lower mold for vulcanizing and molding the outer surface of the bladder, a core mold for vulcanizing and molding the inner surface of the bladder, and includes a lower mold slab land which is a flat surface part for placing the slab thereon and provided on the inner peripheral side of the lower mold, an upper mold slab land that is provided at a position where the upper mold faces the lower mold slab land, has a projecting burr cutting part, cutting a burr, on the inner peripheral side, and presses the slab between it and the lower mold slab land, and an abutting member that is provided on the upper mold to abut on an upper end surface of the lower mold when the upper mold and the lower mold are engaged with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bladder molding mold for molding a bladder used for manufacturing a pneumatic tire.

  Conventionally, a mold in which a bladder is accommodated is used in a vulcanization process of a pneumatic tire. This bladder is molded using a bladder molding mold.

  FIG. 2 is a schematic cross-sectional view of a conventional bladder molding mold. This mold for bladder molding comprises an upper mold 11 and a lower mold 12 for molding the outer surface, and a core mold 2 for molding the inner surface. The upper mold 11 and the lower mold 12 are provided with flat surfaces 11a and 12a called slab brands, respectively.

  First, a slab (rubber production rubber) extruded in a rod shape is placed on the lower slab brand 12a of the lower mold 12. Next, the upper mold 11 and the lower mold 12a are brought into contact with each other by closing the mold and fitting the upper mold 11 and the lower mold 12 together. Thereby, pressing force (compression) is applied to the slab from the slab brand 11a, 12a, and the slab flows into the gap Ga between the upper mold 11 and the lower mold 12 and the core mold 2 to form a bladder ( For example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-34765

  However, when the upper mold and the lower mold are fitted and the upper and lower slab brands are brought into contact with each other, when the upper and lower slab brands are close to each other and the slab becomes thin (about 0.5 mm), Beyond that, the slab cannot flow into the gap and remains on the slab brand and may remain on the product surface as burrs. This burr needs to be removed by cutting with a knife or buffing with a sander and removing it before using it for tire vulcanization. Furthermore, if the buff fails, a discard bladder is generated. This reduces the productivity of the bladder.

  Then, this invention makes it a subject to provide the mold for bladder shaping | molding which suppresses that a burr | flash generate | occur | produces in the bladder after vulcanization shaping | molding, and does not cause a fall of productivity.

The invention described in claim 1
A bladder molding mold that presses the slab and vulcanizes the bladder,
An upper mold and a lower mold for vulcanizing the outer surface of the bladder;
A core mold for vulcanizing the inner surface of the bladder;
The lower mold slab brand that is provided on the inner peripheral side of the lower mold and is a flat surface for placing the slab,
It is provided at a position facing the lower mold slab brand of the upper mold, has a protruding burr cut part for cutting burrs on the inner peripheral side, and presses the slab with the lower mold slab brand With the upper slur brand
Provided in the upper mold, and when the upper mold and the lower mold are fitted, has a contact member that contacts the upper end surface of the lower mold,
When pressing the slab, the slab that could not flow into the inner surface of the upper mold and the inner surface of the lower mold is an outer peripheral side of the upper mold slab brand, the varicut part, and the lower slab brand. The bladder mold is characterized in that the upper mold and the lower mold are configured so as to escape into the gap formed in step (b).

The invention described in claim 2
The burr cut portion has an outer peripheral surface that is inclined inwardly downward at an angle of 0 to 50 degrees with respect to the vertical direction, has a height of 5.0 to 20.0 mm, and a lower end of the burr cut portion. The mold for bladder molding according to claim 1, wherein the width is 5.0 to 15.0 mm.

The invention according to claim 3
The clearance between the varicut part and the lower mold slab brand is 0.01 to 0.07 mm when the upper mold and the lower mold are closed. Item 3. A mold for bladder molding according to Item 2.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that a burr | flash generate | occur | produces in the bladder after vulcanization shaping | molding, and can provide the mold for bladder shaping | molding which does not cause a fall of productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a bladder molding mold according to an embodiment of the present invention and a partially enlarged view of a part of the range. It is typical sectional drawing of the mold for bladder shaping | molding by a prior art.

  Hereinafter, the present invention will be described with reference to the drawings based on embodiments.

1. FIG. 1 is a schematic cross-sectional view of a bladder molding mold according to an embodiment of the present invention, and a partially enlarged view of a part of the mold.

  The mold for bladder molding according to the present embodiment is a mold for vulcanizing and molding a bladder from a slab. As shown in FIG. 1, an upper mold 11 and a lower mold 11 for vulcanizing and molding the outer surface of a bladder as in the prior art. A mold mold 12 and a core mold (not shown) for vulcanizing and molding the inner surface of the bladder are provided.

2. Upper and lower molds The upper mold 11 and the lower mold 12 are each provided with a sliding surface 11b that is an outer peripheral surface of the upper mold 11 and a sliding surface 12b that is an inner peripheral surface of the lower mold 12. The upper mold 11 and the lower mold 12 are fitted by sliding on the sliding surfaces 11b and 12b.

  On the inner peripheral side of the lower mold 12, a lower mold slab brand 12 a that is a flat portion for placing a slab is provided. And the upper mold | type slab brand 11a which presses a slab between the lower mold | type slab brands 12a is provided in the position of the upper mold | type 11 which opposes the lower model slab brand 12a.

  In the present embodiment, a protruding burr cut portion 11d for cutting the slab is provided on the inner peripheral side of the upper die slab brand 11a. Further, the upper mold 11 is provided with an annular contact member 11c that contacts the upper end surface of the lower mold 12 when the lower mold 12 and the upper mold 11 are fitted together.

  When the slab is pressed between the upper mold slab brand 11a and the lower mold slab brand 12a, the slab that could not flow into the inner surface of the upper mold 11 and the inner surface of the lower mold 12 is the upper mold. The upper mold 11 and the lower mold 12 are configured so as to escape into a gap Gb formed by the outer peripheral side of the slab brand 11a, the burr cut part 11d, and the lower slab brand 12a. For this reason, the burr cut part 11d can cut a slab easily.

3. As described above, by providing the burr cut part 11d, a gap Gb for allowing the slab to escape is formed on the outer peripheral side of the upper slab brand 11a, the burr cut part 11d, and the lower slab brand 12a. For this reason, the burr cut part 11d can cut a burr | flash appropriately.

  The burr cut portion 11d has an outer peripheral surface that is inclined inward downward at an angle θ of 0 to 50 degrees with respect to the vertical direction, a height H of 5.0 to 20.0 mm, and the burr cut portion 11d. It is preferable to have a shape in which the width W of the lower end is 5.0-15.0 mm. By adopting such a shape, the slab can be smoothly released into the gap Gb smoothly when pressed, and the formation of burrs can be sufficiently suppressed, and the burrs can be cleanly cleaned near the surface of the bladder to be vulcanized. Can be cut.

  And when the upper mold | type 11 and the lower mold | type mold 12 are closed, it is preferable that the clearance between the burr cut part 11d and the lower mold | type slav brand 12a is 0.01-0.07 mm. Thereby, the thickness of the burr formed from the slab remaining between the upper mold 11 and the lower mold 12 is reduced, and the burr can be reliably removed by the burr cut portion 11d.

4). When the pressure required to flow the contact member slab between the upper mold 11 and the lower mold 12 and the core mold is applied to the upper mold 11 and the lower mold 12, the burr cut portion 11d and the lower mold Since the slab brand 12a abuts with a large force, the burr cut portion 11d may be crushed.

  Therefore, by providing the annular contact member 11c, it is possible to secure the above-described clearance between the burr cut part 11d and the lower mold slab brand 12a and reduce the pressure applied to the burr cut part 11d.

  Specifically, the width of the abutting member 11c is formed to be equal to the width of the abutting portion of the lower mold 12, and the abutting member 11c is fitted to the upper and lower molds 11 and 12. At this time, the pressure applied to the burr cut portion 11d is weakened by coming into contact with the upper end surface of the lower mold 12. Thereby, there is no possibility that the burr cut part 11d will be crushed.

5. Advantages of the present embodiment (1) According to the present embodiment, it is possible to provide a bladder molding mold in which burrs are suppressed from being generated after vulcanization molding of the bladder. That is, a burr cut portion 11d is provided on the inner peripheral side on the mating surface of the upper mold 11, and a gap Gb for allowing the slab to escape is formed by the outer peripheral side of the upper mold slab brand 11a, the burr cut portion 11d, and the lower slab brand 12a. To do. As a result, the rubber that has not completely flown into the gap Ga is released into the gap Gb, so that the burr cut portion 11d can appropriately cut the burr and suppress the occurrence of burr in the product.

(2) In addition, by forming a bladder that does not generate burrs, there is no need to provide a process for cutting or buffing burrs, which can reduce equipment costs and labor costs. Can be improved. Further, it is possible to eliminate the generation of the waste bladder due to the buff failure, and the cost can be reduced.

(Experimental example)
Next, the present invention will be described more specifically based on experimental examples.

1. Production of Test Specimens As shown in Table 1, the current production was performed using the bladder molding molds of Experimental Examples 2 to 8 in which the shape (height, width and angle) of the burr cut part and the presence or absence of the contact member were changed The bladder was molded by the same procedure as above. In addition, a bladder was similarly molded using a conventional bladder molding mold (Experimental Example 1) in which the above-described burr cut portion and contact member were not provided. It should be noted that the amount of slab to be charged was estimated and input in an appropriate amount for forming the bladder in any of the experimental examples.

2. Evaluation It was evaluated whether buffing was necessary for each bladder after molding. The results are shown in Table 1.

  From Table 1, in the experimental example 1 which is a prior art, since the burr cut part was not provided, the burr | flash generate | occur | produced and the buff operation | work was required. In Experimental Example 2, although the burr cut portion was provided, the height of the burr cut portion was insufficient, so that the capacity of the gap Gb was insufficient, and a burr was generated and a buffing operation was necessary.

  On the other hand, in Experimental Example 3, since the burr cut portion having an appropriate height, width and angle was provided, no burr was generated. In Experimental Example 4, although no burr was generated, it was confirmed that the height of the burr cut portion was too high, the capacity of the gap Gb was increased, more slabs were required, and the loss was large.

  In Experimental Example 5, since the width of the burr cut portion was narrow, the capacity of the gap Gb was increased, more slabs were required, and it was confirmed that the loss was large. In Experimental Example 6, since the width of the burr cut portion was large, the capacity of the gap Gb was insufficient, and burrs were generated, which required buffing work.

  In Experimental Example 7, because the angle of the burr cut part was large, the capacity of the gap Gb was insufficient, and burrs were generated, which required buffing work. In Experimental Example 8, the conditions of the burr cut part are the same as in Experimental Example 3. However, since the contact member is not provided, the burr cut part is crushed, resulting in the generation of burr and the need for buffing. It was.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

2 Core mold 11 Upper mold 12 Lower mold 11a Upper mold brand 12a Lower mold brand 11b, 12b Sliding surface 11c Abutting member 11d Varicut part Ga, Gb Clearance H Height of Varicut part W Variety section width θ Varicut angle

Claims (3)

A bladder molding mold that presses the slab and vulcanizes the bladder,
An upper mold and a lower mold for vulcanizing the outer surface of the bladder;
A core mold for vulcanizing the inner surface of the bladder,
The lower mold slab brand that is provided on the inner peripheral side of the lower mold and is a flat surface for placing the slab,
It is provided at a position facing the lower mold slab brand of the upper mold, has a protruding burr cut part for cutting burrs on the inner peripheral side, and presses the slab with the lower mold slab brand With the upper slur brand
Provided in the upper mold, and when the upper mold and the lower mold are fitted, has a contact member that contacts the upper end surface of the lower mold,
When pressing the slab, the slab that could not flow into the inner surface of the upper mold and the inner surface of the lower mold is an outer peripheral side of the upper mold slab brand, the varicut part, and the lower slab brand. The mold for bladder molding, wherein the upper mold and the lower mold are configured so as to escape into the gap formed in step (b).   The burr cut portion has an outer peripheral surface that is inclined inwardly downward at an angle of 0 to 50 degrees with respect to the vertical direction, has a height of 5.0 to 20.0 mm, and a lower end of the burr cut portion. The mold for bladder molding according to claim 1, wherein the width is 5.0 to 15.0 mm.   The clearance between the varicut part and the lower mold slab brand is 0.01 to 0.07 mm when the upper mold and the lower mold are closed. Item 3. A mold for bladder molding according to Item 2.

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