JPH0343709Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an injection molding machine that injection molds a molded article using a synthetic resin kneaded with a magnetic material and simultaneously excites the molded article to form a magnet.

[Conventional technology]

This type of molding machine is equipped with an excitation coil on the facing surface of a fixed platen and a movable platen opposite to the fixed platen, and inside the excitation coil, the movable mold and the fixed mold are connected with magnetism. It is installed together with the mold stand.

Normally, excitation coils generate heat when energized. When a particularly strong magnetomotive force is required (for example, about 50,000 AT), the temperature around the coil should be 100
It can even get close to ℃.

As a result, heat from the excitation coil side is transferred to the mold, which causes it to take longer than usual for the molded product to cool and solidify, which not only slows down the molding cycle but also shortens the life of the excitation coil.

Therefore, in order to prevent the heat from the excitation coil side from reaching the mold side, the magnetic field injection molding machine described in Japanese Utility Model Publication No. 134031/1980 has cooling channels drilled in the coil mounting parts of the fixed plate and the movable plate. The coil fitting part is cooled by the cooling water channel.

[Problem that the invention attempts to solve]

As in this prior art, it is technically extremely difficult to drill cooling channels in the plate as shown in the figure along the annular excitation coil.
Even if this is possible by cutting grooves, in that case, the grooves must be sealed watertight, and the width of the cooling channel will be limited, so cooling water will prevent the coil from generating heat. Further improvements are required to eliminate the disadvantages.

This idea was devised to solve the above-mentioned conventional problem, and its purpose was to avoid the adverse effect on the mold due to heat generation on the excitation coil side by using cooling water without performing any processing on the mold placement plate etc. It is an object of the present invention to provide a plastic magnet injection molding machine which can reliably prevent the above problems and also allows easy attachment of an excitation coil and a cooling means to a mold platen.

[Means for solving problems]

The feature of this invention for the above purpose is that a circular mold placement plate made of magnetic material is fixed to the facing surface of a fixed plate and a movable plate placed opposite to the fixed plate, and a circular mold placement plate made of magnetic material is fixed to the surface of the fixed plate and a movable plate placed opposite to the fixed plate. In a plastic magnet injection molding machine equipped with an excitation coil, the excitation coil is housed in an annular excitation coil unit whose inside is partitioned into a cooling jacket, and the excitation coil and the excitation coil unit are fitted into the mold holder. However, cooling water is interposed between the mold placement plate and the excitation coil.

[Effect]

In the above configuration, since there is cooling water between the mold placement plate and the excitation coil, the heat generated in the excitation coil is cooled by the cooling water, and the heat transferred to the mold placement plate is prevented from cooling and solidifying the molded product. It becomes negligible.

〔Example〕

In the figure, 1 and 2 are fixed plates, 3 is a movable plate, and the movable plate 3 has tie bars 4 and 4 installed across the fixed plates 1 and 2.
It moves forward and backward with respect to the fixed platen 1 by guiding it.

On the opposing surfaces of the movable platen 3 and the fixed platen 1, circular mold placement plates 5 and 6 made of magnetic material are fixed.
An annular excitation coil unit 9 containing an excitation coil 8 is fitted around the mold placement plates 5 and 6.

The inside of this excitation coil unit 9 is divided into a cooling jacket 7, and when the excitation coil unit 9 is attached, the cooling jacket 7 comes into close contact with the outer periphery of each of the mold placement plates 5 and 6. and the excitation coil 8.

10 is a fixed mold, 11 is a movable mold, inside of which magnetic blocks 12, 13 are provided, and the mold placement plates 5, 13 are arranged so that a cavity is created between the magnetic blocks 12, 13. It is attached to 6.

In the figure, reference numeral 14 denotes an injection device, and its nozzle touches the gate of the resin path provided in the magnetic block 12 through a through hole in the center of the mold placement plate 5. Further, 15 is a mold clamping ram, and 16 is a mold clamping cylinder.

In the above structure, when the mold is closed, both molds 1
0 and 11 and magnetic blocks 12 and 13, and when the excitation coil 8 is energized after mold clamping, a magnetic field is generated, and the fixed platen 1 - mold placement plate 5 - fixed mold 10 and magnetic blocks 12 - A magnetic path is formed that spans the movable mold 11 and magnetic block 13, the mold placement plate 6, the movable plate 3, and the tie bar 4. As a result, the molded product 17 in the cavity made of resin kneaded with magnetic material is magnetized and becomes a plastic magnet.

Further, cooling water is supplied to the cooling jacket 7 and the cooling water circulates, so even if heat is generated in the excitation coil 8, the heat is absorbed by the cooling water and the mold placement plates 5, 6 are heated. It will no longer reach.

In the illustrated example, excitation coil units are provided around both mold placement plates, but the excitation coil unit may be provided only on one side.

[Effect of idea]

As mentioned above, this idea houses the excitation coil in a ring-shaped excitation coil unit whose inside is partitioned by a cooling jacket, and the excitation coil and the excitation coil unit are fitted in a mold placement plate, and the excitation coil and the excitation coil unit are fitted together with the excitation coil unit into a mold placement plate. Since the cooling water is interposed between the coil and the coil, there is no restriction such as when drilling a cooling channel on the mold platen side, and the cooling water can be spread equally over the width of the coil. It has a remarkable heat insulating effect compared to , and the molded product can be cooled and solidified at a set temperature regardless of the heat generation on the excitation coil side.

In addition, since both the excitation coil and the cooling water are in the same unit, the excitation coil itself is easily cooled and heat generation is suppressed, extending the coil life. It is easier and requires less effort to install than when processing the mold plate, and there is no problem with attaching or removing the mold, as the mold plate can be left as is. It has characteristics.

[Brief explanation of the drawing]

The drawings show an embodiment of the plastic magnet injection molding machine according to the invention, in which FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a sectional view taken along the line of FIG. 1. 1, 2... Fixed plate, 3... Movable plate, 4... Tie bar, 5, 6... Mold stand, 7... Cooling jacket, 8... Excitation coil, 9... Excitation coil unit, 10... Fixed type, 11...Movable type, 12,1
3...Magnetic block.

Claims (1)

[Scope of utility model registration request] A circular mold placement plate made of magnetic material is fixed to the facing surface of a fixed plate and a movable plate placed opposite to the fixed plate, and a plastic magnet with an excitation coil attached around one or both of the mold placement plates. In the injection molding machine, the excitation coil is housed in an annular excitation coil unit whose inside is partitioned into a cooling jacket,
A plastic magnet injection molding machine characterized in that the excitation coil and the excitation coil unit are fitted into the mold holder, and cooling water is interposed between the mold holder and the excitation coil.