JPS6335344B2 - - Google Patents

Description

[Detailed Description of the Invention] [Prior Art] Generally, in order to form a tire, a gypsum core having the same external shape as the tire is made, and a main mold consisting of a flat plate and a mold surrounds the gypsum core. In the hollow part where
Tire molds are used that are made by injecting and solidifying molten metal such as aluminum alloy.

In this tire mold, the air pressure required to form a tire by vulcanizing raw rubber is applied from the inside of the tire to the outer circumference to form the tire's outer shape, but at this time, the tire surface and tire mold are A large number of small holes called vent holes are formed to penetrate in the radial direction in order to release the air trapped in between and the gas generated from between the raw rubber during vulcanization.

For this reason, a large number of rubber protrusions called spews that flow into the vent holes are formed on the outer surface of the tire that has been vulcanized by the tire mold, spoiling the appearance of the tire, and therefore need to be removed.

Therefore, a method has been considered in which a vent hole extending in a direction parallel to the tire surface is formed in a protruding bone portion of a tire mold corresponding to the tire groove, and a spew is formed in the tire groove.

The conventional method for forming these vent holes is to form a number of recesses in the opposing side walls of the surface groove of the gypsum core, and to insert and bury both ends of the filament into each pair of opposing recesses. It bridges the gap.

The filament is formed of a wire such as a wire, a pin, or a wire, and a heat-resistant solid lubricant layer attached to the surface of the wire so that it can be easily removed after the tire mold is solidified.

The vent holes made of these striated bodies are formed as close as possible to the outer periphery of the tire groove to enhance the effect of removing air and gas, and are formed at the proximal end of the bone part of the mold in a complementary relationship with the tire groove. There is a need.

Therefore, this filament is bridged by the groove on the surface of the plaster core, and its both ends are fixed in the recess with plaster, etc., and then it is cast into the base end of the bone part of the tire mold. By subsequently pulling out the filament from the tire mold, a vent hole is formed in the tire mold.

[Problem that the invention seeks to solve]

Since the filamentous body is thus provided at the proximal end of the bone portion of the tire mold, it is difficult to pull it out.

In other words, the filament is made of a metal wire as mentioned above, and both ends of the filament appear on both sides of the bone, and in order to pull it out of the mold, the wire must be coated very well. Otherwise, it will be difficult to pull it out due to friction.

Not only that, since this filamentous body will be pulled out from the proximal end of the bone part of the tire mold,
This is done between the ribs of the tire mold, making the process even more difficult.

An object of the present invention is to solve the problem in such a method of forming a vent hole for a tire mold that it is difficult to pull out the vent hole forming filament from the proximal end of the bone part of the mold.

[Means for solving problems]

In order to solve the above problems, the present invention provides the following method for forming a vent hole for a tire mold. That is, the present invention involves forming a large number of pairs of recesses in the upper part of the opposing side walls of the groove on the surface of a gypsum core for tire molding, and attaching both ends of a filament made of casting plaster or clay between the opposing recesses. After forming a large number of filamentary bodies in the shape of a bridge on the upper part of the groove, and casting a tire mold by arranging a gypsum core in which the filamentous bodies are formed into a bridge shape in a ring shape, the remaining part in the tire mold is cast. A method for forming a vent hole for a tire mold, characterized in that the striated body is removed using pressurized water to form a vent hole for a tire mold.

[Effect]

The striated bodies made of casting gypsum or clay form vent holes in the tire mold during tire mold casting, but due to their structure, when the tire mold is removed from the gypsum core after casting, the striated bodies form vent holes in the tire mold. remains in the vent hole.

The striatum is then removed from the vent hole by washing it away with pressurized water.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Regarding embodiments of the present invention, how the structure of the present invention is actually embodied will be described below with reference to the drawings, together with its operation.

FIG. 1 is a cross-sectional explanatory diagram of one embodiment of the present invention.
is a gypsum core with the same external shape as a tire, and a molten metal such as aluminum alloy is injected into a hollow part 5 formed by being surrounded by a main mold 4 consisting of a flat plate 2 and a formwork 3 and solidified to form a tire mold 6. It is shown that it forms.

8 in the figure is a groove provided on the surface 7 of the gypsum core 1, and a filament 9 is provided spanning the groove 8.

FIG. 2A is a perspective view of the gypsum core 1, in which recesses 12 and 13 are provided in the side walls 10 and 11 of the groove 8 provided on the surface 7, and both ends 9a of the filament 9 are
9b is placed in the recesses 12, 13, and fillers 14, 15 made of gypsum or the like are filled as shown in FIG. 2B to fix the filament 9 in the recesses 12, 13. It is desirable that the filament 9 be attached to the side walls 10, 11 of the groove 8 at a position as close to the surface 7 as possible.

FIG. 3 is a perspective view of the cast tire mold 6.

A tire mold 6 is made by pouring molten metal such as aluminum alloy into a space 5 formed by a main mold 4 and a plaster core 1 shown in FIG.
The surface shape is opposite to the unevenness of the gypsum core 1 shown in FIG. 2A, and the concave groove 8 in FIG. 2A forms a convex bone portion 16 in FIG. 3. 17 and 18 are the sides.

Also, the side wall 1 near the surface 7 of the groove 8 in FIG. 2A
Striatum 9 attached like a bridge to 0 and 11
As shown in FIG. 3, a vent hole 19 is formed in the tire mold 6 by the casting, but when the cast tire mold 6 is taken out from the main mold 4 and the plaster core 1, there are structural problems. Due to circumstances, both ends 9a and 9b of the filament body 9 are bent and the filament body 9 remaining in the vent hole 19 of the tire mold is made of casting plaster or clay.
It can be easily removed by rinsing with pressurized water.

[Effects of the Invention] As described above, the present invention provides a method for removing the filaments remaining in the tire mold by attaching a filament made of casting plaster or clay to the grooves of a plaster core and forming a tire mold using the filament as the core. Since the vent hole is formed by removing the body with pressurized water, the removal work of the striae body is extremely easy, and the vent hole can be formed regardless of the shape and size of the bone of the tire mold, and the position direction of the vent hole. be able to.

Further, since the filament is not pulled out as in the conventional method, there is an advantage that the shape of the vent hole can be freely determined.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional explanatory diagram of an embodiment of the present invention;
Fig. 2A is a perspective view of a gypsum core according to an embodiment of the present invention, Fig. 2B is a perspective view of a main part of Fig. 2A, and Fig. 3 is a tire mold cast using the gypsum core of Fig. 2A. FIG. 1... Gypsum core, 6... Tire mold, 7...
...Surface of gypsum core, 8...Groove, 9...Striatum, 1
0, 11... Groove side wall, 12, 13... Recess, 1
9...Vent hole.

Claims (1)

[Claims] 1. A large number of pairs of recesses are formed in the upper part of the opposing side walls of the groove on the surface of a gypsum core for tire molding, and both ends of a filament made of casting plaster or clay are attached between the respective opposing recesses, and the above-mentioned A large number of filaments are formed in the shape of a bridge on the upper part of the groove, and a gypsum core with these filaments formed in the shape of a bridge is arranged in a ring, and the molten metal is placed in the space formed by this core and the main mold. After pouring aluminum alloy and casting the tire mold,
A method for forming a vent hole for a tire mold, the method comprising forming a vent hole for a tire mold by removing the filamentous body remaining in the tire mold using pressurized water.