JPS5939302B2 - Vulcanization mold exhaust mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the exhaust mechanism of a vulcanizing mold for an elastomer article 1, for example, a tire. A screw hole is formed at a predetermined depth on the inner surface of the mold in the through hole, and one or two ventilation holes are provided in the screw hole having a threaded portion on the outer surface and communicating with the outer surface in the length direction. It is characterized by a cylindrical screw piece having a screwdriver groove and a driver groove on the upper surface.

Conventionally, in tire vulcanization, vent holes 1, 8 to 1, called vent holes 1, as shown in Fig. 1, are used to remove accumulated air from the mold in order to bring the rubber surface into close contact with the mold surface of the mold. Mold A is used, which has a large number of small holes of about 2.0 mm in diameter so that the inner and outer surfaces of the mold communicate with each other, but after tire vulcanization, these vent holes 1 spoil the product appearance on the surface of tire B. Since a large number of thorn-like protrusions 2 called spikes are produced, a step of cutting them out with a cutter is necessary.

However, in so-called white side wall tire nuts, it is difficult to cut out the thorn-like protrusions 2 with a cutter, and for this reason, when curing this type of tire, for example, 0.6關φdegree/hJL4
A mold A is used in which a so-called vent piece 3 with a hole is inserted into a vent hole 1 as shown in FIG.

However, with such a vent piece, it is not necessary to remove the spill after vulcanization, but rubber often gets clogged in the small hole during tire vulcanization, and in this case, use a rubber clog cleaning needle to remove the clogged rubber. However, if the needle broke midway and remained inside the vent piece, the mold had to be removed from the press and the vent piece inside the mold had to be replaced each time.

In addition, in tubeless tires, if the length of the spill at the bead of the tire is not within about 1 mm, air may leak from this spill when the rim is assembled and the tire is in use, which is undesirable. Because it is difficult to cut out the vent holes and vent pieces, conventional vent holes and vent pieces cannot be used, resulting in frequent occurrence of minor defects such as bare peas.

In view of the above points, the inventors of the present invention have studied to improve the exhaust mechanism of tire curing molds, and have developed a vent piece that maintains the advantage of the vent heath, which eliminates the need to remove the tire spill after vulcanization. They discovered an exhaust mechanism that can be easily replaced when it becomes clogged.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The exhaust mechanism of the present invention will be described in detail below with reference to the accompanying drawings showing one embodiment thereof.

Namely, as shown in FIG. A screw hole (for example, 3 mm diameter with a screw pitch of 0.5 mm) is formed on the inner surface at a predetermined depth p (for example, about 5 mm) from the inner surface, and then a screw piece 13 made of iron or brass is inserted into this screw hole 12. It has a suitable structure.

The shape of this screw piece 13 has a threaded portion 14 on its outer surface, as shown in FIGS. 5 and 6, for example.
It is a cylindrical body having the same diameter over its entire length, and is provided with ventilation grooves 15 along its entire length.

This groove 15 can be formed by cutting, for example.

Air remaining between the mold surface of the mold and the rubber surface during vulcanization passes through the groove 15 and is discharged to the outside surface of the mold through the through hole 11.

The depth C of the cut groove 15 that functions in this way is approximately 0.3
~0.5 mm, and its width W is preferably about 0.2~0.5 mm.

This is because if the length exceeds 0.5 in either case, the force will exceed 1 length, which is not good.

The cross-sectional shape of the cut groove 15 may be V-shaped, U-shaped, U-shaped, or other inclined shape.

The screw piece 13 may have one or two cut grooves 15, and two grooves are most preferable.

Further, a driver groove 16 for attaching to and detaching from the mold A is provided on the upper surface of the screw piece 13.

Therefore, screwing the screw piece 13 having such a cut groove 15 into the screw hole 12 of the mold A requires a screw.
This can be done using the driver groove 16 on the top surface of the piece 13 (
The driver groove 16 is preferably a minus groove as shown in FIG. 5, but may also have a hexagonal shape or a two-point shape (both not shown).

When the driver groove 16 is a minus groove as shown in FIG. 5, if this groove is communicated with the ventilation cut groove 15, the efficiency of air removal during vulcanization is improved.

Further, when the screw piece of the present invention is employed in the heel part of the bead ring part 17 as shown in FIG. By communicating with the tire, the efficiency of air removal during vulcanization is further improved, and the finished appearance of the bead portion of the tire is improved.

As mentioned above, by performing tire vulcanization using a mold for an exhaust mechanism in which the screw piece of the present invention is screwed into the screw hole of the vent hole, (1) the tire surface can be vulcanized in the same manner as in the case of the vent hole. No excision step is required.

In other words, when using this screw piece, air escapes through the cut groove, but the rubber does not get into several parts,
In addition, even if it does enter, the spill formed will be fine.
(0.3 mm) and short (0.3 to 0.5 mm at most)
), so the excision step is no longer necessary.

(2) Since it has a threaded structure, even if the cut groove of the screw piece becomes clogged with rubber or foreign matter, the screw piece can be easily replaced on-site using a screwdriver while the mold is still attached to the press. .

(3) If this screw piece is used in the bead ring part of a tubeless tire mold, even if a spill occurs, it will be extremely thin and short, so there is no risk of air leakage during use of the tire, and therefore the tubeless tire will be lightweight. Defects can be completely eliminated.

Various effects such as these can be obtained.

The numerical values shown in the above description are for explaining the present invention in more detail, and the present invention is not limited to these numerical values in any way.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a conventional vent hole in a tire mold, Fig. 2 is a perspective view showing the shape of a conventional vent piece, and Fig. 3 is an explanatory diagram showing a conventional vent piece in a tire mold. Fig. 4 is an explanatory diagram showing the exhaust mechanism of the present invention, Fig. 5 is a perspective view showing an example of a screw piece used in the exhaust mechanism of the present invention, and Fig. 6 is the same (plan view and side view). Fig. 7 is an explanatory diagram when the exhaust mechanism of the present invention is applied to a bead ring part.A...Mold, B-...Tire, 11...Through hole, 1
2...Screw hole, 13...Screw piece, 15.
... Cut groove, 16... Driver groove.

Claims (1)

[Claims] 1. In a vulcanization mold, a plurality of through holes are drilled that communicate the inner and outer surfaces of the mold, and a screw hole is formed at a predetermined depth on the inner surface of the mold in the through hole, and the outer surface is connected to the screw hole. A cylindrical screw piece having a threaded portion on the outer surface thereof, one or two ventilation grooves communicating in the longitudinal direction on the outer surface, and a driver groove on the upper surface is screwed. Exhaust mechanism for sulfur mold.