JP2000025077A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding in which molded articles with different shapes can be simultaneously molded by one mold and productivity can be improved. SOLUTION: In a mold for injection molding wherein first and second cavities 7 and 9 with different shapes are provided in the parting line between a fixed mold 2 and a movable mold 3 and molded articles with different shapes are simultaneously molded in one mold, a first gate 15 introducing a molten resin into the first cavity from the outside of the molded article, a first sprue bush 20 opening on the parting line of the fixed mold for introducing the molten resin into the second cavity 9 and freely movable back and forth in the axial direction and a first driving mechanism 24 forwarding the first sprue bush in the movable mold direction during injection and opening a gate part 22 are provided and in the movable mold, a second sprue bush 32 facing the first sprue bush so as to be communicated with it, a second valve pin 33 and a second gate 37 for introducing the molten resin into the second cavity 9 from the inside of the molded article, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold capable of simultaneously molding two types of molded articles having different shapes with one mold.

[0002]

2. Description of the Related Art In an injection molding die for molding a molded product, a plurality of cavities are provided in one molding die, a molten resin injected from a molten resin injection port is distributed, and the molten resin is injected into the cavity while being kept warm. It is configured to lead to a communicating gate.

[0003] This injection molding die is constructed so that a plurality of molded products can be molded simultaneously by one injection molding. Basically, one molten resin is provided in a sprue portion provided in a central portion. It has an inlet and a branch passage that branches into a plurality of ports in communication with the inlet. On the other hand, a plurality of cavities are provided in the mold body, and a plurality of nozzle holder units having gates communicating with these cavities are provided. Further, a hot runner manifold having a heater is connected to communicate the branch passage of the sprue portion with each of the nozzle holder units, and is configured to guide the injected molten resin in a warm state.

Accordingly, the molten resin injected from the molten resin injection port is distributed to a plurality of runners via a branch passage, guided from these runners to a gate via a plurality of nozzle holder units, and further transferred from the gate to each cavity. Is injected into.

[0005]

However, in general, an injection mold is used to mold one or a plurality of molded articles at the same time, and one mold can simultaneously mold molded articles having different shapes. unknown. In addition, in an injection molding die for simultaneously molding a plurality of or a large number of molded products with one die, since the cavities are dense, the gate position for injecting the molten resin into each cavity is restricted. Therefore, although the spacing between the cavities is designed to be wide, there is a problem that the mold body becomes large and heavy.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an injection molding die which can simultaneously mold molded articles having different shapes with one die.

Another object of the present invention is to provide an injection mold capable of reducing the space between the cavities and reducing the size of the mold body. Another object is to provide an injection mold capable of preventing resin from leaking from a molten resin passage during and after injection molding.

[0008]

According to the present invention, in order to achieve the above object, a first aspect of the present invention comprises a fixed mold and a movable mold which can be separated from and connected to the fixed mold. An injection molding die, in which first and second cavities having different shapes are provided on a divided surface of a die and a movable die, and molded products having different shapes are simultaneously formed by a single die. A resin inlet, a resin passage communicating with the resin inlet, a first gate communicating with the resin passage to guide the molten resin from the outside of the molded product to the first cavity, and opening and closing the first gate. A first gate pin to communicate with the resin passage and a first gate pin that opens and closes in a dividing surface of the fixed mold and the movable mold to guide the molten resin to the second cavity; The sprue bush and the first sprue bush And one of the valve pin, and a drive mechanism for opening the gate of the first sprue bushing retracting said first valve pin with advancing said first sprue bushing on the movable mold direction during injection provided.

A second sprue bush opposing the movable mold so as to be able to communicate with the first sprue bush; a second valve pin inserted into the second sprue bush; A second cavity which communicates with the sprue bushing of the second and guides the molten resin from the inside of the molded article to the second cavity.
And a second gate pin for opening and closing the second gate.

According to a second aspect, the driving mechanism according to the first aspect includes:
A first hydraulic cylinder provided in the fixed mold, a first piston provided in the first hydraulic cylinder to drive the first sprue bush, and a first piston provided in the first piston. And a second piston provided in the second hydraulic cylinder to drive the first valve pin.

According to the above construction, the first gate for guiding the molten resin from the outside of the molded article to the cavity and the second gate for guiding the molten resin from the inside of the molded article to the cavity are provided, so that the cavities are densely packed. Even if they are arranged, there is no restriction on the gate position. Also, the first divided
Since the surface pressure of the divided surface of the second sprue bush is increased at the time of injection, resin leakage from the divided surface can be prevented.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an injection mold,
2 is a sectional view taken along line AA in FIG. 1, and FIG.
It is sectional drawing which follows the B line. As shown in FIGS. 1 to 3, the injection mold 1 includes a fixed mold 2 and a movable mold 3 that can be brought into contact with and separated from the fixed mold 2. A resin injection port 4 is provided at the center of the fixed mold 2, and a first molding part a for molding four first molded articles a is formed on one side of the injection molding die 1 with the resin injection port 4 as a boundary. The molded part 1A is provided on the other side with a second molded part 1B for molding four second molded parts b having a shape different from that of the first molded part a.

The movable mold 3 of the first molding portion 1A is provided with a truncated cone-shaped core portion 5, and a dish-shaped portion is provided between the top of the core portion 5 and the dividing surface 6 of the fixed mold 2. The first cavity 7 is provided. The first cavity 7 is dish-shaped, and a flange is provided on the outer peripheral surface. Second forming part 1
The movable mold 3 of B is provided with a truncated cone-shaped core portion 8, a dish-like shape is formed between the top portion of the core portion 8 and the dividing surface 6 of the fixed mold 2, and a convex portion 9 a is formed at the bottom portion. A second cavity 9 is provided.

A first hot runner 13 is provided on the fixed mold 2 located on the axis of the core portion 5 of the first molding portion 1A. The first hot runner 13 is connected to the resin inlet 4
And a resin passage 14 communicating with the resin passage 14. The first hot runner 13 is provided with a first gate 15 for guiding the molten resin to the first cavity 7, and the first gate 15 is provided with a first gate pin 17 for opening and closing a gate section 16. This gate pin 17 is connected to a hydraulic piston mechanism 18.

A second hot runner 19 communicating with the resin passage 14 is provided in the stationary mold 2 facing between the four second cavities 9 of the second molding portion 1B. The second hot runner 19 has an axially movable first sprue bush 2 that opens in a dividing surface 6 between the fixed mold 2 and the movable mold 3 in order to guide the molten resin into the second cavity 9.
0 is provided. Further, a first valve pin 21 is inserted into the first sprue bush 20 so as to be able to advance and retreat in the axial direction so as to open and close the gate portion 22.

A driving mechanism 24 for driving the first sprue bush 20 and the first valve pin 21 is provided on the fixed mold 2 located at the base end side of the first sprue bush 20 and the first valve pin 21. I have.

The drive mechanism 24 includes a first hydraulic cylinder 25 formed of a concave portion provided in the fixed mold 2 and a first hydraulic cylinder 25 provided in the first hydraulic cylinder 25 and integrated with the first sprue bush 21. Piston 26, a second hydraulic cylinder 27 formed of a concave portion provided in the first piston 26, and a first hydraulic cylinder 27 provided in the second hydraulic cylinder 27.
And the second piston 28 connected to the valve pin 22. Further, the first and second pistons 2
A first hydraulic circuit 29 for driving the first and second pistons 28 and 28 and a second hydraulic circuit 30 for driving the second piston 28 forward are provided.

The second hot runner 19 and the movable mold 3 located on the axis are provided with a third hot runner 31 opening to the dividing surface 6. The third hot runner 31 has a second hot runner 31. A sprue bush 32 is provided. A second valve pin 33 is inserted into the second sprue bush 32 so as to be able to advance and retreat in the axial direction, and opens and closes the gate portion 34. That is, the base end of the second valve pin 33 is connected to the hydraulic piston mechanism 35. Also, the second
The sprue bush 32 communicates with the resin passage 14 provided in the movable mold 3.

Further, a fourth hot runner 36 is provided in the core portion 5 of the second molded portion 1B. The fourth hot runner 36 is provided with a second gate 37 for guiding the molten resin to the second cavity 9, and the second gate 37 opens and closes a gate portion 38 opening inside the second cavity 9. A second gate pin 39 is provided, and this gate pin 39 is connected to the hydraulic piston mechanism 40.

Next, the operation of the first embodiment will be described. When the molten resin is injected from the injection molding machine into the injection mold 1 through the resin injection port 4, the molten resin is guided to the first hot runner 13 and the second hot runner 19 via the resin passage 14. Here, when the gate pin 17 is retracted by the drive of the hydraulic piston mechanism 18, the first gate 1
The gate 16 of 5 opens and the molten resin is injected and filled into the first cavity 7.

On the other hand, when hydraulic pressure is applied from the first hydraulic circuit 29 to the first hydraulic cylinder 25, the first hydraulic piston 2
When the first sprue bush 20 moves forward as a whole and the first sprue bush 20 advances integrally, the front end face of the first sprue bush 20 presses the end face of the second sprue bush 32 to apply a surface pressure. Therefore, it is possible to prevent the resin from leaking from the dividing surface 6. At the same time, a hydraulic pressure is applied from the first hydraulic circuit 29 to the second hydraulic cylinder 27, so that the second hydraulic piston 28 retreats, the first valve pin 21 retreats integrally, and the gate portion 22 opens. . At the same time, the second valve pin 33 is retracted by the hydraulic piston mechanism 35, and the gate 34 is opened. Therefore, the molten resin in the second hot runner 19 is guided to the resin passage 14 of the movable mold 3 via the second sprue bush 32. Further, the second gate pin 39 is retracted by the hydraulic piston mechanism 40, the gate 38 is opened, and the molten resin is injected into the second cavity 9 and filled.

When the first cavity 7 and the second cavity 9 are filled with the molten resin in this way, the gate pin 17 advances by the hydraulic piston mechanism 18 to close the gate portion 16 of the first gate 15. Also, the second hydraulic piston 27 advances by the hydraulic pressure from the second hydraulic circuit 30, the first valve pin 21 advances, and the gate portion 22
And the valve pin 33 advances by the hydraulic piston mechanism 35 to close the gate portion 34. further,
The second gate pin 39 advances by the hydraulic piston mechanism 40 to close the gate portion 38 of the second gate 37.

After the molten resin filled in the first cavity 7 and the second cavity 9 is cooled and solidified, when the movable mold 3 retreats with respect to the fixed mold 2, the first cavity 7 and the second A first molded product a and a second molded product b can be obtained from the cavity 9 of the above, and two types of molded products a and b having different shapes.
Can be formed simultaneously.

In the above-described embodiment, the mold for simultaneously molding the dish-shaped molded articles a and b has been described.
The present invention is not limited to the shape of the molded product.
Further, the first sprue bush 20 is advanced by the first hydraulic piston 26 at the time of injection while the end faces of the first and second sprue bushes 20 and 32 are opposed to each other. The driving mechanism that performs the operation is not limited to the above embodiment.

[0025]

The present invention has the following functions and effects because it is configured as described above. a. Molded products having different shapes can be simultaneously molded with one mold, and productivity can be improved. In addition, since the number of molds can be reduced by half, the cost of molded products can be significantly reduced. b. Butt the ends of the split sprue bush,
By increasing the surface pressure during injection, it is possible to prevent the resin from leaking from the divided surface. c. 1st guide of molten resin from outside of molded product to cavity
By providing the first gate and the second gate for guiding the molten resin into the cavity from the inside of the molded product, the size of the mold body can be reduced without restriction on the gate position even when the cavities are densely arranged. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view of an injection molding die showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

[Explanation of symbols]

 Reference numeral 2: fixed mold 3: movable mold 15: first gate 17: first gate pin 20: first sprue bush 21: first valve pin 24: drive mechanism 32: second sprue bush 33: second Valve pin 37 ... Second gate 39 ... Second gate pin

Claims (2)

[Claims] 1. A fixed mold comprising a fixed mold and a movable mold which can be brought into contact with and separated from the fixed mold. First and second cavities having different shapes are formed on a dividing surface of the fixed mold and the movable mold. Provided, 1
What is claimed is: 1. An injection molding mold for simultaneously molding molded articles having different shapes with two molds, wherein the fixed mold is provided with a resin inlet, a resin passage communicating with the resin inlet, and a resin passage communicating with the resin passage. A first gate for guiding the resin from the outside of the molded product to the first cavity;
A first gate pin for opening and closing the first gate, and an axial direction opening on a dividing surface of the fixed mold and the movable mold to communicate with the resin passage and guide the molten resin to the second cavity. A first sprue bush that can move forward and backward, a first valve pin inserted into the first sprue bush, and a first sprue bush that is advanced in the direction of the movable mold during injection and the first sprue bush. A drive mechanism for retracting the valve pin to open the gate portion of the first sprue bush; a second sprue bush opposing the movable mold so as to be able to communicate with the first sprue bush; A second valve pin inserted into the sprue bush, a second gate communicating with the second sprue bush and guiding the molten resin from the inside of the molded product to the second cavity; An injection molding die, comprising a second gate pin for opening and closing the second gate. 2. The drive mechanism includes a first hydraulic cylinder provided in the fixed mold and a first hydraulic cylinder provided in the first hydraulic cylinder for driving the first sprue bush.
, A second hydraulic cylinder provided in the first piston, and a second piston provided in the second hydraulic cylinder and driving the first valve pin. The injection mold according to claim 1, wherein