JPS59207Y2 - Rubber molds - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a mold for molding rubber.

In general, injection molding of rubber requires a vulcanization process of heating inside the cavity after the injection process into the cavity, unlike the molding which is completed by cooling after injecting thermoplastic synthetic resin into the cavity. .

Therefore, the heat of this vulcanization process is transmitted to the runner block, causing so-called scorch, where the unvulcanized rubber inside the runner is partially vulcanized, resulting in defective products, or when molding is stopped for a long time. The problem was that the rubber inside the runner block was vulcanized and could not be reused.

This invention solves the above-mentioned difficulties, and also
The purpose is to improve yield by reducing the occurrence of sprue loss, etc.

Another purpose is to simply form the runner instead of providing holes for cooling water passages in the runner block itself as in the past, simplifying the structure and making it lightweight, making the runner block easier to handle. The purpose is to

In order to achieve the above object, this invention provides a mold for molding rubber, in which a cavity in a pair of mold bodies and a runner in a runner block are communicated with each other through a cold tip. , a cassette-type split mold in which a runner is formed through a stepped part, this runner block is fitted into a notch of a holding plate, and this holding plate is sandwiched between cooling plates provided with cooling water circulation holes therein, A heat insulating plate is interposed and fixed to the mold body, and a spiral cooling water groove is provided inside the cold chip, and the cold chip is arranged so that an air gap is formed in the mold body. It is characterized by:

An embodiment of this invention will be described below based on the drawings.

In the figure, 1 is a cassette type runner block,
Consists of a pair of split molds.

A runner 4 is formed within this runner block 1 via a stepped portion 3.

This runner block 1 has a notch 21 formed in a holding plate 20.
The holding plate 20 is held between the cooling plates 2.

The cooling plate 2 has a plurality of cooling water circulation holes 5 inside.
are bored, and both ends of these holes 5 are connected by a connecting hose (not shown) to form a cooling water channel.

The mold body 7 fixed to the cooling plate 2 via the heat insulating plate 6 includes a pair of mold plates 8 and 9 that can be pressed and separated, and the mold plates 8 and 9.
A cavity 11 is formed inside, and a heater loading hole 13 into which an appropriate number of electric heaters 12 are loaded is provided.

The eject turbine 10 has a distal end portion 10A formed in a dish shape, so that the rubber filled into the cavity 11 flows out in the direction of the circumferential side of the eject turbine 10 through the filling pressure of the rubber. Tip part 10
The A-receiver is prevented by pressing the tip 10A against the surface.

In addition, when molding a cylindrical rubber molded product, by providing a protrusion 14 on the front end surface of the tip portion 10A so as to match the axis of the ejector turbine 10, the molded product can be pulled out from the gate 11A. becomes easier.

Between the mold body 7 and the runner block 1, there is a cold chip 15 that communicates the cavity 11 with the runner 4.
It is arranged so as to form an air gap 16 with the mold body 7.

This cold chip 15 is provided with a runner 17 and a cooling water groove 1B spirally arranged around the runner 17 for circulating cooling water.

Next, to explain its use, unvulcanized rubber is passed through the runners 4 and 17 into the cavity 1 by an injection device (not shown).
1 and then vulcanized by heating, the mold body 7 is separated by the movement of the movable mold plate 9,
The ejector turbine 10 is ejected by an air cylinder (not shown), and compressed air is blown from the air blowing passage 19 provided between the circumferential side of the ejector turbine 10 and the mold body 7, and the molded product is separated from the mold body 7. be done.

The temperature of the cooling water circulated through the cooling water passages of the cooling plate 2 and the cold chip 15, that is, the holes 5 and the cooling water grooves 18, is variable, and the temperature is adjusted according to the properties of the rubber to be injected.
and a temperature at which vulcanization is not possible (e.g. 40° to so'c)
shall be.

Further, the heater 12 of the mold body 7 is set to maintain the mold temperature at 160° to 180° C. for vulcanization.

This invention, which is constructed as shown above, has a runner block 1.
is a cassette-type split mold in which a runner 4 is formed through a stepped portion 3, and this runner block 1 is fitted into a notch 21 of a retaining plate 20, and a hole 5 for cooling water circulation is formed inside this retaining plate 20.
Since it is sandwiched between the cooling plates 2 provided with a runner block, there is no need to provide a runner and a cooling water passage inside the block as in a conventional runner block, and the structure of the runner block can be simplified.
The weight of the runner block 1 itself can be reduced.

Therefore, the runner block 1 can be easily handled, and when molding is to be stopped for a long time, the runner block 1 can be easily removed from the mold body 7 and stored under cooling.

Therefore, vulcanization of the rubber inside the runner block 1 can be prevented,
Can be reused.

In addition, there is no need to provide holes 5 for cooling water circulation in the runner block 1 itself, making processing easy, and when replacing the mold body 1, the runner block 1 that matches the mold body 7 can be replaced in a cassette type. Since it only needs to be replaced, the configuration can be simplified and the replacement operation is very easy.

Furthermore, since the runners 4 are formed through the stepped portions 3, even if the runner block 1 is made into a small split mold that can be easily attached and removed, a so-called cassette-type split mold, the high-pressure rubber inside the runner 4 can be used as a split mold. The step portion 3 can prevent the water from flowing out from the mating surface, and the effect of the step portion 3 allows the runner block 1 to be made into a cassette type split type.

In other words, the configuration of the stepped portion 3 in the case of a cassette-type split mold clearly differs from the effect of a mere stepped portion that is normally used, and brings about the above-mentioned special effects.

Since the runner block 1 is sandwiched between the cooling plates 2 having a cooling water passage inside and fixed to the mold body 7 with the heat insulating plate 6 interposed, the heat of the mold body 7 for vulcanization is transferred to the runner block. In addition, it is possible to keep the rubber inside the runner block 1 cold to the extent that it does not vulcanize. This saves the trouble of taking out the rubber inside the runners 4 and 17, which was done at the same time.
The rubber inside 7 can be used for the next molding.

Therefore, the runner block 1 is opened and the runners 4, 1
Since there is no need to take out the rubber inside 7, continuous automatic molding of rubber is possible with a simple configuration, material loss is reduced, and scorch can be prevented.

A spiral cooling water groove 18 is provided inside the cold tip 15, and the cold tip 15 is disposed in the mold body 7 so that an air gap 16 is formed.
Runner 17 of Cold Chip 15 improves the insulation effect with
Can prevent vulcanization of the rubber inside.

As explained above, this invention makes it possible to mold rubber with a high yield, without causing scorch, and furthermore, enables continuous automatic molding of rubber with a simple configuration. In addition, the structure of the runner block is simple and lightweight, making it easy to handle and process.

This has extremely beneficial effects in practical terms.

[Brief explanation of drawings]

The drawings show one embodiment of this invention, and FIG. 1 is a partially cutaway overall front view, and FIG. 2 is a sectional view taken along the line II--II in FIG. 1. 1...Runner block, 2...Cooling plate, 3...Step, 4...Runner, 5...
... Hole, 6 ... Heat insulation plate, 7 ... Mold body, 8, 9 ... Template plate, 10 ... Eject turbine, IOA ...Tip, 11...
...Cavity, 11A...Gate, 12
...Electric heater, 13 ... Heater loading hole, 14 ... Protrusion, 15 ... Cold tip, 16 ... Air gap, 17
...Runner, 1B...Cooling water groove, 19
... Air blowing passage, 20 ... Holding plate, 21 ... Notch.

Claims (1)

[Scope of utility model registration request] In a mold for molding rubber, in which a cavity in a pair of mold bodies and a runner in a runner block are communicated with each other through a cold chip, the runner is formed in the runner block through a stepped part. A cassette-type split mold is used, and this runner block is fitted into the notch of the holding plate, and this holding plate is sandwiched between cooling plates that have holes for circulating cooling water inside, and is fixed to the mold body with a heat insulating plate interposed. On the other hand, a mold for molding rubber, characterized in that a spiral cooling water groove is provided inside the cold chip, and the cold chip is disposed in a mold body so as to form an air gap.