JPH06143358A - Injection mold - Google Patents

Abstract

PURPOSE:To provide an injection mold, in which the heat insulating properties between a valve body and a mold body opposite to the valve body can be improved and the sure temperature controlling of a gate part can be carried out. CONSTITUTION:By ceramic member 30, which is interposed in a gap 20 made between the end part of a valve body (or a valve bushing 6 and a tip member 10) and the inner surface of the conical hole 12 of a gate bushing 11, resin is prevented from entering in the gap 20, resulting in keeping the heat insulating effect in the gap 20. At the same time, due to the low heat conductivity of the ceramic member 30 itself, the heat energy flowing through the ceramic member 30 is checked to the utmost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve gate type injection molding die for opening and closing a gate at the tip of a movable rod.

[0002]

2. Description of the Related Art A valve gate type injection molding die of this type is known, for example, as shown in FIG. This injection molding die will be described. In FIG. 2, reference numeral 1 is a fixed mold plate, and a movable mold plate 2 is provided so as to be movable toward and away from the fixed mold plate 1.
A cavity 3 having a shape of a molded product is formed between the mold plates 1 and 2. A fixed mounting plate 4 and a fixed mounting plate are mounted on the fixed mold plate 1 via a spacer block (not shown), and a manifold 5 is installed between the fixed receiving plate 4 and the fixed mounting plate. ing. A valve bush 6 is mounted inside the fixed receiving plate 4 and the fixed mold plate 1, and a coil-shaped heater 7 is provided on the outer periphery of the valve bush 6. And
A heater cover 8 and a tubular member 9 are attached to the outer circumference of the coiled heater 7. Further, the valve bush 6
A tip member 10 is screwed to the tip of the fixed mold plate 1 facing the tip member 10, the valve bush 6, the heater cover 8 and the tubular member 9.
Is installed. The gate bush 11 is formed in a funnel shape whose diameter decreases toward the tip, and the inner peripheral surface of the tip of the gate bush 11 is a conical hole 12. Then, in the conical hole 12, the tip member 10
The valve bush 6 is attached, and the funnel-shaped gap 20 communicating between the conical hole 12 of the gate bush 11 and the tip member 10 and the valve bush 6 communicates with the inside (gate) 11a of the tip of the gate bush 11. And the gap formed between the heater cover 8 and the gate bush 11 communicates with the gap 20.
Further, on the outer peripheral surface of the base end portion of the gate bush 11, a cooling passage 14 communicating with a cooling passage 13 formed in the fixed mold plate 1 is formed.
A pair of O is provided between the gate bush 11 and the fixed mold plate 1.
Rings 15 and 16 are attached. The guide member 1 is provided between the valve bush 6 and the tip member 10.
7, the guide member 17 includes an outer cylinder attached to the valve bush 6, an inner cylinder guiding and supporting the movable rod 18, and a plurality of support plate portions connecting the inner and outer cylinders. It is configured. Furthermore, the inside of each of the manifold 5 and the valve bush 6, the inner and outer cylinders of the guide member 17, the inside of the tip member 10 and the gate bush 11 are further described.
The molten resin is supplied to the cavity 3 through the inside (gate) 11 a of the tip of the. A closing member 19 is installed inside the valve bush 6 and is supported and guided by the inside of the closing member 19 and the inner cylinder of the guide member 17, so that the movable rod 18 slides along its axis. It is designed to move.

In the injection molding die having the above-described structure, the movable rod 18 is slid in the mold clamping state in which the fixed mold plate 1 and the movable mold plate 2 are closed. , The gate 11a is opened, and the molten resin is supplied to the inside of each of the manifold 5 and the valve bush 6, between the inner and outer cylinders of the guide member 17, the inside of the tip member 10 and the gate bush 11.
It is supplied to the cavity 3 through the inside (gate) 11a of the tip of the. Next, the movable rod 18 is slid to close the gate 11a, and the resin in the cavity 3 is cooled and solidified. Then, the space between the fixed mold plate 1 and the movable mold plate 2 is opened to open the cavity 3 Release the molded product inside. In this case, the valve bush 6 and the tip member 10 are heated by the coiled heater 7 in order to keep the resin supplied into the cavity 3 in a molten state, whereas the gate bush 11 is In order to quickly cool and solidify the resin in 3, the cooling passages 13, 1
It is cooled by the cooling water circulated in 4. And
Especially, in the vicinity of the gate 11a, the gate bush 1
1 and the gap 20 formed between the valve bush 6 and the tip member 10, these gate bushes 1
1 and the valve bush 6 and the tip member 10 are insulated from each other.

[0004]

By the way, in the external heating method having the coil heater 7 provided outside the valve bush 6, the coil heater 7 is connected to the gate 11.
Since it is difficult to dispose in the vicinity of a, it is difficult to finely control the temperature of the gate 11a portion by controlling the coil heater 7. In addition, the valve bush 6
The resin in the tip member 10 and the resin in the tip member 10 must be kept in a molten state at all times by heating.
Since the resin filled inside must be solidified quickly by cooling, a gap 20 for heat insulation is formed between the gate bush 11 and the valve bush 6 and the tip member 10 as described above. There is this gap 20
As the width of the gap increases, the heat insulation effect increases, but the gap 20
When the width is increased, the resin is likely to enter the gap 20 through the gate 11a, and air having a high heat insulating effect is removed, which rather lowers the heat insulating effect.

The present invention has been made in view of the above circumstances, and an object thereof is to improve heat insulation between a valve body and a mold body facing the valve body, and An object of the present invention is to provide an injection molding die capable of reliably controlling the temperature of a part.

[0006]

In order to achieve the above object, the present invention provides a cavity between a pair of mold plates,
A resin passage communicating with the cavity via a gate is provided in one of the template plates, and a movable rod is arranged in the valve body forming the resin passage so as to be movable in the axial direction. In the injection molding die for opening and closing, the gate side end of the valve body is formed in a taper shape, and the gate side end of the valve body is attached to the mold plate facing the gate side end of the valve body. A mounting hole for mounting is formed, and a gap is formed between the gate-side end of the valve body and the inner surface of the mounting hole of the template, and a ceramic member is interposed in this gap. .

[0007]

In the injection molding die of the present invention, the resin that penetrates into the gap by the ceramic member interposed in the gap between the gate side end of the valve body and the inner surface of the mounting hole of the mold plate. And the heat insulating effect in the gap is maintained, and the thermal energy flowing through the ceramic member is suppressed as much as possible due to the low thermal conductivity of the ceramic member itself.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the present embodiment, parts having the same configurations as those of the conventional example shown in FIG.

In this embodiment, the gate bush 11
A funnel-shaped ceramic member 30 is mounted in a gap 20 formed between the valve bush 6 and the tip member 10. Here, the reason why the ceramic member 30 is adopted is that the material to be mounted in the gap 20 has a very low thermal conductivity, a heat resistant temperature of 400 ° C. or higher, and has a certain degree of strength. This is because good things are required.

In the injection molding die having the above-mentioned structure, the movable rod 18 is held in the mold clamping state as in the conventional case.
Is moved and the gate 11a is opened to inject resin into the cavity 3. Then, the movable rod 18
Is moved to close the gate 11a. Then, after the resin in the cavity 3 is cooled and solidified, the space between the fixed mold plate 1 and the movable mold plate 2 is opened, and the molded product inside is released.
In this case, the valve bush 6 and the tip member 10 are
In order to keep the resin supplied into the cavity 3 in a molten state, it is heated by the coiled heater 7,
The gate bush 11 is cooled by cooling water flowing through the cooling passages 13 and 14 in order to quickly cool and solidify the resin in the cavity 3. Since a gap 20 is formed between the gate bush 11 and the valve bush 6 and the tip member 10, the ceramic member 30 is mounted in the gap 20. The resin does not enter from the 11a side, and the heat insulation of the ceramic member 30 thermally insulates the gate bush 11 from the valve bush 6 and the tip member 10, thereby controlling the temperature of the gate 11a. It becomes possible to perform surely.

[0011]

As described above, according to the present invention, a cavity is formed between a pair of mold plates, and a resin passage communicating with the cavity through a gate is provided in one mold plate.
In addition, in the injection molding die in which a movable rod is arranged in the valve body that constitutes the resin passage so as to be movable in the axial direction, and the tip of the movable rod opens and closes the gate, the gate side end of the valve body is tapered. And a mounting hole for mounting the gate-side end of the valve body is formed in the template plate facing the gate-side end of the valve body. Since a gap is formed between the plate and the inner surface of the mounting hole, and the ceramic member is interposed in this gap, the ceramic member prevents resin that enters the gap, and In addition to maintaining the heat insulation effect, the low thermal conductivity of the ceramic member itself suppresses the thermal energy flowing through the ceramic member as much as possible, and To be able to improve the thermal insulation between the mold body direction, it is possible to reliably control the temperature of the gate portion.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional injection mold.

[Explanation of symbols]

 1 Fixed mold plate 2 Movable mold plate 3 Cavity 6 Valve bush (valve body) 10 Tip member (valve body) 11 Gate bush 11a Gate 12 Conical hole (mounting hole) 18 Movable rod 20 Gap 30 Ceramic member

Claims (1)

[Claims] 1. A cavity is formed between a pair of mold plates,
A resin passage communicating with the cavity via a gate is provided in one of the template plates, and a movable rod is arranged in the valve body forming the resin passage so as to be movable in the axial direction. In the injection molding die for opening and closing, the gate side end of the valve body is formed in a taper shape, and the gate side end of the valve body is attached to the mold plate facing the gate side end of the valve body. A mounting hole for mounting is formed, and a gap is formed between the gate side end of the valve body and the inner surface of the mounting hole of the template, and a ceramic member is interposed in the gap. And injection molding dies.