JPH0218011A - Method for vulcanizingly molding tire - Google Patents

Abstract

PURPOSE:To prevent green rubber form intruding between a sector and side plates and consequently obtain a tire having favorable external appearance recesses are formed in advance at positions corresponding to mating surfaces, at which the sector and the side plates abut against each other, on the outer lateral faces of a green tire. CONSTITUTION:Groove-like recesses (r) are formed in advance circumferentially on the outer lateral faces of both the right and left sides of a green tire G before its charging to a mold for vulcanizing molding. The positions of the recesses (r) correspond to those of the mating surfaces, at which a sector 1 and side plates 2 abut against each other. Next, the green tire G is set inside the sector1 of the mold under its open state. Further, the inner pressure of a bladder is raised up to the predetermined high pressure so as to press the green tire G against the molding surface of the mold in order to bring the tire into close contact with the surface. At said pressing, the recesses (r) disappear, resulting in bringing the whole outer lateral face of the green tire into close contact with the molding surface of the mold. The vulcanizingly molding operation completes by performing the vulcanization of the tire through its heating for the predetermined period of time under the above-mentioned state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tire vulcanization molding method, and more particularly to a tire vulcanization molding method using a sectional mold.

[Prior art]

A sectional tire mold has a structure that consists of a sector for tread molding, which is divided into multiple sectors in the circumferential direction by a dividing plane in the radial direction, and side plates for sidewall molding provided on both sides of the sector. It has become. When vulcanizing a tire using this sectional mold, first separate multiple sectors radially outward,
A green tire is set inside the tire, and then the sector is moved toward the inner green tire (unvulcanized tire) until it comes into contact with the outer circumferential surface of the side plate, and an operation is performed to close it to form an annular shape.

However, in the conventional method, when the sector 1 comes into contact with the outer peripheral surface of the side plate 2 in such a sector moving operation, as shown in FIG. 3, the unvulcanized rubber on the outer surface of the green tire G is It is bitten as shown in b,
Overflow may occur. The area where the unvulcanized rubber overflows remains as a crisp after molding, which significantly impairs the appearance of the tire and reduces the product value.

Therefore, in the past, it was necessary to trim these edges before making the final product, which caused a decrease in productivity.

In addition, if unvulcanized rubber is frequently caught in the mating surface between the sector and the side plate, it will cause early damage to the mold and reduce the durability of the mold. was. There is also the problem that a great deal of effort is required to repair this damage.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the problems when using a sectional mold as described above, to obtain a tire with a good appearance without trimming, and to improve tire productivity and durability of the mold. An object of the present invention is to provide a method for vulcanization molding a tire that improves properties.

[Means to solve the problem]

The present invention achieves the above object by using a sectional mold consisting of sectors for tread molding which are divided in the circumferential direction into a plurality of parts by a dividing plane in the radial direction, and side plates for molding sidewalls on both the left and right sides. When the tire is vulcanized and molded, an inwardly recessed part is formed in advance on the outer surface of the green tire, corresponding to the mating surface where the sector and the side plate abut. It is something to do.

By forming a recess in advance on the outer surface of the green tire in this way, it is possible to eliminate the unvulcanized rubber from getting caught in the closing operation of the sector, and it also improves the appearance of the tire after molding. be able to.

Hereinafter, the present invention will be specifically described with reference to embodiments shown in the drawings.

FIGS. 1 and 2 show a situation in which the vulcanization molding method of the present invention is carried out using a sectional mold, in which sector 1 is for forming a tread, and sector 2 is for forming a side plate. The sector 1 is obtained by dividing the circumferential direction of the tread into a plurality of sectors by a dividing surface in the radial direction, and these sectors 1. -9■ is assembled into a ring to form a tread mold part. A pair of left and right side plates 2 are assembled on both sides of sectors 1, -, 1 set in an annular shape in this manner.

Multiple sectors 1. -・-11 are respectively radially outer (
It is movable in the direction of arrow A) and inward (in the direction of arrow B), and during vulcanization molding, a green tire G is set inside it and the tire is moved in the direction B until it comes into contact with the outer peripheral surface of side play) 2.2. By moving it, it can be closed in a circular ring.

On the other hand, the green tire G before being subjected to vulcanization molding in such a mold is preliminarily formed with groove-like recesses r and r along the circumferential direction on the outer surfaces of both left and right sides thereof. .

The position where the recess r is provided must correspond to the position of the mating surface when the sector 1 contacts the side plate 2.

In the present invention, the green tire G having the recess r formed in advance on the outer surface as described above is vulcanized and molded using the sectional mold as follows.

First, sector 1 of the mold. -11 is expanded in the direction of arrow A, and green tire G is set inside it. At this time, a bladder (not shown) is inserted inside the green tire G, and by feeding low pressure air into this bladder, the green tire G is set at a predetermined position. At the position where the green tire G is set in this way, the recesses r formed on both left and right sides,
r corresponds to the mating surface where the sector 1 and the left and right side plates 2.2 meet.

Next, the sectors 1, -, 1 are moved inward in the direction of arrow B until they come into contact with the outer peripheral surface of the side plate 2.2, and are closed in an annular shape.

At this time, there is a recess r on the outer surface of the green tire G, which is retracted inward, so there is an unvulcanized part b between sector 1 and side plate 2 as shown in Rubber biting does not occur.

Next, the internal pressure of the bladder is increased to a predetermined high pressure, and the green tire G is pressed toward the molding surface to bring it into close contact. By this pressing, the recess r disappears, and the entire outer surface of the green tire G comes into close contact with the molding surface.

In this state, heating is performed for a predetermined period of time to perform vulcanization, and the vulcanization molding operation is completed.

The tire after vulcanization does not have the above-mentioned cracks caused by overflow of unvulcanized rubber, so there is no need for further trimming as in the past, and the final product has a good appearance. be able to. Therefore, tire productivity can be improved.

Furthermore, as described above, since there is no unvulcanized rubber biting, damage to the mold can be reduced, and the durability of the mold can be improved.

〔Effect of the invention〕

As described above, in the present invention, when a green tire is vulcanized and molded using a sectional mold, a recess is formed in advance on the outer surface of the green tire, corresponding to the mating surface where the sector and the side plate come into contact. This prevents unvulcanized rubber from getting caught between the sector and the side plate.

Therefore, it is possible to manufacture a product tire with a good appearance without requiring any trimming work, and it is also possible to improve tire productivity and mold durability.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view in the radial direction of a sectional mold to explain the situation when carrying out the vulcanization molding method of the present invention;
The figure is a sectional view taken along the line nn in FIG. 1. Third
The figure is a longitudinal cross-sectional view of the main part of a mold to explain the state of the conventional vulcanization molding method. 1...Sector 2...Side plate, G...
Green tire, r... recess. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] When vulcanizing and molding a green tire using a sectional mold consisting of sectors for tread molding, which are divided into a plurality of sectors in the circumferential direction by dividing planes in the radial direction, and side plates for molding sidewalls on both left and right sides, the above-mentioned method is used. A method for vulcanizing and molding a tire, in which a concave portion recessed inward is previously formed on the outer surface of a green tire, corresponding to the mating surface where the sector and the side plate abut.