JPS6367114A - Mold assembly for vulcanizing tire - Google Patents

Abstract

PURPOSE:To prevent unnecessary projections from developing on a vulcanized tire by a method wherein the fitting parts of a top force and of a bottom force are joined through a sealing member and at the same time a vent hole is made on the fitting part. CONSTITUTION:The fitting parts 3 of a top force 1 and of a bottom force 2 are joined through a sealing member 6. In addition, a vent hole 7 to communicate the inner face of a mold with its outer face is made on the side face of the fitting part 3 of the top force 1. Further, a semicircular vent groove 8 to communicate the vent hole 7 with the interior of a mold main body 4. Under the state that a green tire W is set between the top force 1 and the bottom force 2, the top force 1 is lowered so as to fit at the fitting part 3. When the fitting part 3 starts to abut against the sealing member 6, vacuumizing is started by means of an air sucking means 9. After the top force 1 and the bottom force 2 are completely closed, vacuumizing is continued through the vent groove 8 and the vent hole 7 so as to discharge the air stagnated between the inner faces 1a and 2a of the molds and the green tire W. Consequently, almost no improper projection develops on the surface of a vulcanized tire.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a tire curing mold, and more specifically to a two-part mold that joins an upper mold and a lower mold at a fitting portion. A new tire vulcanizing mold device that improves the discharge of air trapped between the unvulcanized tire and the mold body, and prevents unnecessary protrusions from forming on the vulcanized tire. This relates to mold equipment.

[Prior art]

Conventionally, a two-piece tire curing mold body 4 in which an upper mold 1 and a lower mold 2 are joined at a fitting part 3 is shown in FIG.
1 to FIG. 3 (as shown in C1, the mold inner surface 1a contacts various parts of the surface of the unvulcanized tire W.

2a and an exhaust hole 5 penetrating between the mold outer surfaces 1b and 2b.
A plurality of holes are drilled at locations where air tends to stagnate, so as to discharge the stagnant air between the mold inner surfaces 1a, 2a and the unvulcanized tire W.

However, since such a conventional exhaust hole 5 has a large hole diameter (typically diameter IM1 to 31 m), unvulcanized rubber material easily flows into the exhaust hole 5 together with the gas when the gas is discharged, resulting in vulcanization. There was a problem in that protrusions Q unsuitable for use as a tire product were formed on the surface of the sulfurized tire W1 (see FIG. 4).

For this reason, conventionally, when the tire W is vulcanized, an extra step is required to cut and remove the protrusions Q that are unsuitable for the tire product, leading to a problem in that the molding cost increases.

Therefore, various molds have been proposed as molds that do not require two steps to process the protrusions Q.
Special Publication No. 45-5896, Publication No. 56-39623
No. 1, JP-A-60-52314, JP-A-60-
112405). For example, a surface in which one or more microscopic ventilation holes are provided in the axial direction at the inner opening of the exhaust hole of the mold] A structure in which a vent plug made of rusty metal or synthetic resin is fitted. is proposed. This mold increases the ventilation resistance of the ventilation hole of the air vent plug and makes the length of penetration of the rubber material into the ventilation hole short and fine, so that it can be formed on the surface of the rubber molded product. This prevents the appearance of the product from being damaged even if the protrusions are not removed. However, the protrusions formed on the surface of the rubber molded product by this mold are minute column-shaped, so when the rubber molded product is released from the mold and taken out, it is easy to cut from the tip or base. , the cut protrusion remains and the ventilation hole is completely closed. For this reason, there was a problem in that the function as a ventilation hole was quickly lost and the mold could not withstand long-term use.

[Purpose of the invention]

This invention was devised by focusing on such conventional problems, and its purpose is to create a structure in which almost no unnecessary protrusions are generated on a vulcanized tire, and to eliminate unnecessary protrusions after tire molding. To provide a tire vulcanizing mold device which eliminates the work of removing objects, reduces costs in tire molding work, and allows the mold body to be used for a long period of time.

[Structure of the invention]

In order to achieve the above object, the present invention provides a two-piece tire vulcanizing mold in which an upper mold and a lower mold are joined at a fitting portion. At the same time, a ventilation hole is formed in the radial direction at at least one part of this fitting part, and a ventilation groove that is connected to the ventilation hole and communicates with the inside of the mold body is formed. By connecting the ventilation hole formed in the fitting part to the intake means, air trapped between the unvulcanized tire and the mold body can be effectively discharged, and unnecessary protrusions on the vulcanized tire can be removed. The gist of this is to ensure that almost no occurrence of

[Embodiments of the invention]

The present invention will be described in detail below with reference to FIGS. 1A to 1C and 2 of the accompanying drawings.

In the following description, the same components as those of the above-mentioned conventional example will be described with the same reference numerals.

In the figure, 4 indicates a two-piece tire curing mold body in which an upper mold 1 and a lower mold 2 are joined at a fitting part 3, and the upper mold 1 and the lower mold 2 are connected to each other at a fitting part 3. The fitting portion 3 is joined via a seal member 6 (an O-ring is used in this embodiment). A radial ventilation hole 7 is formed on the side surface of the fitting part 3 of the upper mold 1 and communicates between the inner and outer surfaces of the mold. A semicircular arc-shaped ventilation groove 8 is formed.

Note that the ventilation holes 7 are not limited to one tree, and may be formed in plural numbers.

Further, a vacuum pump, referred to as suction means 9, is connected to a ventilation hole 7 formed on the side surface of the fitting portion 3 of the upper mold 1.

In FIG. 1(a+) to FIG. 1(C), reference numeral 10 indicates a ventilation hole provided near the tire bead portion, and reference numeral 11 indicates a tire bead ring.

Next, the operation of the two-piece tire curing mold device will be explained.

First, as shown in FIG. 2 and 2 are fitted together at the fitting part 3 and begin to abut against the sealing member 6, as shown in FIG. 1(b).
As shown in FIG. 2, vacuuming is started using the vacuum pump, which is referred to as the suction means 9.

After the upper mold 1 and the lower mold 2 are completely closed as shown in FIG. Remaining air between 1a, 2a and the unvulcanized tire W is discharged.

By doing so, as shown in FIG. 2, almost no intrusive protrusions were generated on the surface of the vulcanized tire W1.

The above effects were carried out under the following conditions.

(a), Tire type: 185/70R13 (b) Number of 8 ventilation holes: 3 locations on the circumference (C) Diameter of 1 ventilation hole: Φ5 (d) 0 Ventilation groove shape: radius of Φ1.5 (e), The length of the fitting part is near 0111 (f), the vacuum time: 30 seconds before and after fully closing [Effects of the Invention] The present invention provides two methods for joining the upper mold and the lower mold at the fitting part as described above. In a split-type tire vulcanization mold device, a fitting portion between the upper mold and the lower mold is joined via a sealing member, and at least one part of the fitting portion is radially oriented. A ventilation hole is formed, a ventilation groove is formed that connects to this ventilation hole and communicates with the inside of the mold body, and the ventilation hole formed in the fitting part is connected to an air intake means, so there is no need for it after tire molding. This has the effect of omitting the work of removing protrusions and reducing costs in tire molding work, and as a result, the mold body can be used for a long period of time.

[Brief explanation of the drawing]

FIG. 1 (al to FIG. 1 (C1 is a cross-sectional view and an operation explanatory diagram of a two-piece tire curing mold device in which the present invention is implemented,
FIG. 2 is a perspective view of a tire molded by the apparatus of the present invention, and FIGS. Fig. 4 is a perspective view of a tire molded by a conventional device. 1... Upper mold, 2... Lower mold, 3... Fitting part, 4... Two-piece tire. Vulcanization mold body, 6...
Seal member, 7...Vent hole, 8...Vent groove 8° phase press fit) Fig. 4

Claims (1)

[Claims] In a two-piece tire vulcanizing mold device that connects an upper mold and a lower mold at a fitting part, the fitting part of the upper mold and the lower mold is joined via a sealing member. At the same time, a ventilation hole is formed in at least one part of the fitting part in the radial direction, and a ventilation groove is formed that connects to the ventilation hole and communicates with the inside of the mold body. A tire curing mold device characterized in that a vent hole is connected to an air intake means.