JPS59220341A - Injection molding machine of multi-layered molded article - Google Patents

Abstract

PURPOSE:To enhance the control accuracy and transmission efficiency of injection holding pressure, by performing injection molding by blocking a resin passage by revolving the inside nozzle of an injection head without performing the same by the screw of an injection apparatus. CONSTITUTION:A common injection head 30, which injects the first resin material guided from a first injection apparatus 10 and the second resin material guided from a second injection apparatus 20, is provided. This injection head 30 is constituted of an outside nozzle 36 and an inside nozzle 38 arranged in concentrical relationship and an operation rod 40 which is positioned in the inside nozzle 38 and can close the nozzle orifice 36 provided to the leading end thereof and further provided with a revolving apparatus 70 for revolving the inside nozzle 28. In this case, the inner nozzle 38 is revolved by the revolving apparatus 70 to block the passage 16 of the first resin material and injection holding pressure is exerted to the first resin material by the inside nozzle 38 to perform injection molding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection molding machine for producing a plastic multilayer molded product, and particularly relates to a multilayer molded product having a foamed core and a non-foamed outer skin covering the surface of the core. This invention relates to an injection molding machine for molding.

Conventionally, this type of multilayer molded product, a molded product having a Zunawara core and an outer skin surrounding it, and especially a multilayer molded product having a foamed core and a non-foamed outer skin, has been produced. For this purpose, Special Publication No. 55-45374, Special Publication No. 55-5
Various injection molding machines have been disclosed, including Japanese Patent Publication No. 0770 and Japanese Patent Publication No. 56-30169. Therefore, these injection molding machines generally share an injection head with a double nozzle structure consisting of an outer nozzle and an inner nozzle, and the outer shell material and the core material are respectively applied to the injection head. A first and a second injection device (cylinder) are connected to each other for separate injection, and such injection head is connected to a sprue of a predetermined mold so that the material injected from the respective injection device is guided into the cavity of the mold through the injection head to mold a predetermined multilayer molded product.

However, in such conventional injection molding machines, after a predetermined resin material is injected and filled into the mold, the pressure is lower than the injection pressure, in other words, the injection holding pressure is maintained. This is due to the fact that the injection pressure from the injection device, that is, the screw extrusion pressure, is now used when applying the pressure to the mold, and as a result, the distance between the injection device and the mold inevitably becomes longer. However, since the control precision of the injection holding pressure and injection holding amount is not sufficient, and since such injection holding pressure is applied by the screw of the injection device, during that time the injection device is rotated and the resin material is not injected. It was not possible to perform operations such as plasticizing, and this was a problem in shortening the molding cycle.

The present invention has been made in view of the above circumstances, and its purpose is to provide injection molding in which injection holding pressure can be applied not to the screw of the injection device but to the injection head. The goal is to provide opportunities.

In order to achieve this object, the present invention provides a first resin material introduced from a first injection device and a second resin material introduced from a second injection device into a predetermined mold. an outer nozzle and an inner nozzle, each of which has a common injection head for ejecting the liquid, and the injection head is arranged concentrically;
The actuating rod is located inside the inner nozzle and can close the nozzle hole at the tip thereof, and a rotating means for rotating the inner nozzle is provided, and the inner nozzle is rotated by the rotating means. The passage of the first resin material guided from the first injection device between the inner nozzle and the outer nozzle is blocked, and the injection holding pressure is applied to the second resin material at the inner nozzle. This made it possible to apply

Therefore, according to the present invention, the rotation of the inner nozzle blocks the resin passage provided between the inner nozzle and the outer nozzle, and the resin material present in front of the inner nozzle is passed through. Therefore, a predetermined injection holding pressure is applied to the mold, which improves the control accuracy of the injection holding pressure and injection holding amount.Also, although the injection device is shut off, backflow is prevented. This improves the efficiency of transmitting the holding pressure to the cavity, and furthermore, the injection device itself is freed from the step for applying the injection holding pressure.
The injection device can be rotated by the screw even when the injection holding pressure is applied, making it possible to shorten the molding cycle.

EMBODIMENT OF THE INVENTION Hereinafter, in order to clarify the present invention more specifically, one embodiment of the present invention will be described in detail based on the drawings.

First, in FIG. 1, reference numeral 1o denotes a first injection device, which is equipped with a predetermined screw I4 inside a cylinder 12 as in the conventional case, and is heated by a heater (not shown) attached to the outer circumferential surface. The first resin material supplied into the cylinder 12 is pressurized by the screw 14,
It is fluidized and injected in the same manner as before.

The resin material injected from the first injection device 10 is led to a common injection head 30, which will be described later, through the resin passage 16.

Further, the second injection device 20 is the first injection device IO.
Similarly, a screw 24 is provided in the cylinder 22, and the second resin 7117 material is pressurized, fluidized and injected under heating by a heater (not shown), and is guided into the common injection head 3o through the resin path VI126. It looks like this.

By the way, the injection head 3o includes a hollow outer nozzle 34 having a nozzle hole 32 at its tip, and a hollow inner nozzle 38 having a nozzle hole 36 at its tip, which is accommodated in the outer nozzle 34 and arranged concentrically. The actuating rod 40 is positioned concentrically within the inner nozzle and is capable of closing the nozzle hole 36 at its tip. The tip portions of the inner nozzle 38 and the operating rod 40 are formed into small diameter portions 42.44 having a small outer diameter over a predetermined length, so that the resin materials injected from the two injection devices 10.20 are guided respectively. It has become.

More specifically, the first resin material injected from the first injection device 10 and supplied through the resin passage 16 is applied to the first resin material formed between the small diameter portion 42 of the inner nozzle 38 and the inner surface of the outer nozzle 34. The outer nozzle 34
The inner nozzle 38 is positioned near the opening of the resin passage 16 passing through the support member 46 to which the base of the inner nozzle 38 is attached.
A recess 48 is provided on the outer surface of the inner nozzle 38 , and fan-shaped grooves 50 are provided symmetrically from the recess 48 on both sides of the outer peripheral surface of the inner nozzle 38 and extend toward the small diameter portion 42 . By communicating the recess 48 and the groove 50, the first resin material is introduced into the gap between the small diameter portion 42 of the inner nozzle 38 and the outer nozzle 34.

Further, the resin passage 26 that guides the second resin material injected from the second injection device 20 passes through the mounting support part 1tt464 of the outer nozzle 34 and opens into the recess 52 formed on the inner surface thereof. . A communication hole 54 passing through the inner nozzle 38 is provided so as to communicate with the recess 52, and a recess 56 is provided on the surface of the actuating rod 40 so as to communicate with the communication hole 54. A small diameter portion 44 is provided and extends symmetrically to the left and right sides following the recess 56.
A fan-shaped groove 58 is provided on the side, and these resin passages 2
6, recess 52, communication hole 54. By communicating the recess 56 and the groove 58, the second resin material injected from the second injection device 20 can reach the small diameter portion 4 of the actuating rod 40.
4 and the inner surface of the inner nozzle 38. Note that the fan-shaped groove 50 provided on the outer circumferential surface of the inner nozzle 38 described above is similar to the fan-shaped groove 58 provided on the outer circumferential surface of the actuating rod 40 .

Additionally, the base of the inner nozzle 38 and the actuating rod 40 are connected to the first
As shown in the figure, each first nozzle cylinder 60
and three types of hydraulic chambers 64 and 66 connected to the second nozzle cylinder 62 and formed within these nozzle cylinders.
．． By supplying a predetermined pressure oil to 68, the inner nozzle 38 and the operating rod 40 are moved in their axial directions independently or in conjunction with each other. For example, by the movement of the inner nozzle 38, the outer nozzle 34 is moved. Nozzle hole 3
2 is closed or opened at the tip of the inner nozzle 38, and by moving the actuating rod 40, the inner nozzle 3 is closed or opened.
8 nozzle holes 3'6 can be closed or opened.

Furthermore, a rotation device 70 for rotating the inner nozzle 38 is provided at the base portion of the inner nozzle 38 that passes through the support member 46 to which the outer nozzle 34 is attached.
is provided. As shown in FIG. 2, this rotating device 70 includes the support member 46 and the first nozzle cylinder 6.
A mounting plate 74 is slidably attached to a stay 72 located diagonally between the two mounting plates 74, and a key 76 is inserted between the two mounting plates 74. A rotating member 78 is provided which is engaged with the outer peripheral surface of the inner nozzle 38. This rotating member 78 has an action portion 80 extending laterally from its circular periphery, and this action portion 80
A piston rod 84 of a rotating cylinder 82 that is pivotally supported by the mounting plate 74 is pivotally attached to the mounting plate 74 , and the operation of the rotating cylinder 82 causes the rotating member 78 to move through the operating portion 80 .
By rotating the inner nozzle 38, the inner nozzle 38 is rotated by a predetermined angle via the key 76. Note that the rotating member 78 is connected to the operating portion 80.
It has a stopper part 86 symmetrically to the stopper part 86, and is brought into contact with a stopper 90 under the control of an adjustment screw 88 provided on the stopper part 86, so that the amount of rotation of the rotating member 780 is regulated. It has become.

Therefore, in an injection molding machine having such a structure, the injection operation is performed in accordance with the following operations.

That is, first, FIG. 1 shows a mode in which the state is maintained in a neutral state, and the inner nozzle 38 and the operating rod 40 are moved forward by the operation of the first nozzle cylinder 60 and the second nozzle cylinder 62, and the inner nozzle 38 is moved forward. The nozzle hole 32 is closed by abutting the inner tip of the outer nozzle 34, while the tip of the actuating rod 40 is inserted into and abutting the inner nozzle 38, thereby causing the inner nozzle 34 to close the nozzle hole 32. Nozzle hole 3 of nozzle 38
6 is also blocked. Moreover, the inner nozzle 38 is arranged so that the first and second resin materials introduced from the first and second injection devices 10 and 20, respectively, are not introduced into the injection head 30, as shown in FIG. To prevent the recess 48 from communicating with the passage 16 of the first resin material,
Further, it is held at a predetermined rotational position so that the communication hole 54 is not communicated with the recess 52 following the passage 26 of the second resin material. In this state, the first resin material and the second resin material are pressurized and fluidized in the first injection device 10 and the second injection device 20 in the same manner as before, respectively. be.

Then, when the injection head "30 is pressed and the mold (not shown) is closed, and injection preparations are completed, the inner nozzle 38 is opened by the operation of the first nozzle cylinder 60, as shown in FIG. While the inner nozzle 38 is moved backward, the inner nozzle 38 is rotated by a predetermined amount by the rotation device 70.
As shown in FIG. 5, the passage 16 communicates with a recess 48 provided in the outer circumferential surface of the inner nozzle 38, thereby allowing the first resin material to be injected from the first injection device 10, e.g. When injection molding a foam molded article with an outer skin), the outer skin material made of non-foaming synthetic resin passes through the resin passage 16, the recess 48 communicating therewith, and the fan-shaped groove 50, and then passes through the small diameter portion 42 of the inner nozzle 38. The liquid is introduced into the gap between the inner nozzle 38 and the inner surface of the outer nozzle 34, and is injected into a predetermined mold through the nozzle hole 32 opened by the retreat of the inner nozzle 38.

At this time, the operating rod 40 is also rotated in accordance with the rotation of the inner nozzle 38 by the rotation device 70, so that the second resin material passage 26 is connected to the communication hole 54 through the recess 52. Furthermore, it is communicated with the recess 56 and the sector-shaped groove 58 on the side of the actuating rod 40, so that the second resin material can be introduced into the injection head 30.
The actuating rod 40 is still held in a state similar to the neutral state of FIG.
In the state shown in FIGS. 4 and 5, the second resin material is blocked by the injection head 3.
There is no such thing as being ejected from zero.

Next, after a predetermined amount of the first resin material as the outer skin material is injected, as shown in FIG. By opening the nozzle hole 36 and holding the circular nozzle 38 in the same state as shown in FIG. 5, as shown in FIG. 7, the second resin material from the second injection device 20 is released. As a result, a coring material made of a foamable resin material such as a synthetic resin containing a foaming agent is passed from the resin passage 26 through the recess 52, the communication hole 54, the recess 56 on the operating rod 40 side, and the fan-shaped groove 58. It is guided into the gap between the small diameter portion 44 of the actuating rod 40 and the inner surface of the inner nozzle 38, and is injected from the nozzle hole 36 at the tip of the inner nozzle 38, thereby causing the outer skin material and the core material to be ejected. are injected at the same time, and a resin flow positioned such that the core material is centered and the outer skin material surrounds it is guided into a predetermined mold from the nozzle hole 32 of the outer nozzle 34,
In this way, a predetermined foam molded article with a skin is injection molded.

When the injection of the cored material (second resin material) from the second injection device 20 is completed, the actuation rod 40 is ejected as shown in FIG. 8 by the operation of the second nozzle cylinder 62. This closes the nozzle hole 36 at the tip of the inner nozzle 38, while the rotating device 70 is activated at some point to return the inner nozzle 38 to its original neutral state (see FIG. 3). ), and as a result, the resin path R8
16 and 26 and their respective passages in the injection head 30 are cut off, so that neither of the two resin materials can be supplied into the injection head 30. In this state, the injection and holding of the outer skin material (first resin material) is carried out, and the injection holding pressure is such that when the injection pressure from the first injection device 10 is applied, the inner nozzle 38 to block the resin passage as described above, the injection pressure of the first injection device WIO can be used as the injection holding pressure, and the resin passage can be blocked by the inner nozzle 38. After the,
By moving the inner nozzle 38 forward, the first resin material existing in the space between the inner nozzle 38 and the outer nozzle 34 can maintain injection under a desired pressure.

As described above, according to the device having such a configuration, the injection and holding of the first resin material is performed by the first injection device (specifically, the screw 1
4), but the inner nozzle 38, and since the outer diameter of the inner nozzle 38 can be made smaller than the screw 14 of the first injection device, such injection holding is also possible. Since this can be performed only by the injection head 30 and not by the screw 14 of the first injection device IO, which is far away from the mold as in the past, the control accuracy of the injection holding pressure and the injection holding amount can be significantly improved. In addition, in the injection holding state (Fig. 8), the rotation of the inner nozzle 38 causes the release of both the outer skin material (first resin material) and the cored material (second resin material). Since the material passage is blocked, there is less backflow of molten resin to the injection device side, and this also provides the advantage of good transmission efficiency of holding pressure to the mold cavity.

Furthermore, due to the rotation of the inner nozzle 38, the respective resin passages 16 and 26 are both blocked from the resin passage of the injection head 30, so when such injection holding pressure is applied, , the screw can be rotated in both the first injection device 10 and the second injection device 20, thereby pressurizing and fluidizing the resin materials for the next molding cycle, respectively, and starting the next molding operation. This made it possible to shorten the molding cycle and improve productivity.

The present invention is not to be construed as being limited to the specific examples illustrated above, and various improvements can be made based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
, changes, modifications, etc. can be made, and the present invention includes all such aspects.

As described above, the present invention does not use the screw of the injection device to hold the injection, but instead blocks the resin passage by rotating the nozzle inside the injection nozzle, thereby increasing the injection holding pressure. This invention has achieved excellent effects such as improving the control accuracy of the injection retention amount, increasing the transmission efficiency of the retention pressure, and shortening the molding cycle, and these are the great industrial significance of the present invention. It exists.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a cross-sectional view of essential parts showing an example of the device according to the present invention, Fig. 2 is a schematic cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a schematic cross-sectional view of the injection head. FIG. 4 is an explanatory diagram showing the positional relationship of resin passages, recesses, communication holes, grooves, etc. in a cross-sectional state;
The figure is a sectional view of the injection head portion corresponding to FIG. 1 in the first resin monthly injection state, FIG. 5 is a view corresponding to FIG. 3 in such a state, and FIG. FIG. 7 is a sectional view of the injection head portion corresponding to FIG. 1 showing a state where the resin material and the second resin material are simultaneously injected, FIG. 7 is a view corresponding to FIG. 3 in such a state, and FIG. The figure is a sectional view of the injection head portion corresponding to FIG. 1 showing a state in which the first resin material is injected and held, and FIG. 9 is a view corresponding to FIG. 3 in such a state. . ■0; First injection device 16: Resin passage 20; Second injection device 26: Resin passage 30: Injection head 32: Nozzle hole 34
:Outer nozzle 36: Nozzle hole 38: Inner nozzle 4
0: Actuation rod 42.44: Small diameter portion 48: Recess
50: Groove 52: Recess 54: Communication hole 56: Recess 58: Groove 60: First nozzle cylinder 62: Second nozzle cylinder 70: Rotating device 72 Nisty 76: Key 78: Rotating member 82: Rotating cylinder 84: Piston rod applicant Meiki Seisakusho Co., Ltd.

Claims (1)

[Claims] A common injection head is provided for injecting a first resin material introduced from a first injection device and a second resin material introduced from a second injection device into a predetermined mold, and the injection head is configured to
It consists of an outer nozzle and an inner nozzle that are arranged concentrically, an operating rod that is located inside the inner nozzle and can close the nozzle hole at the tip thereof, and a rotating means for rotating the inner nozzle. and the inner nozzle is moved from the first injection device by rotation of the inner nozzle by the rotation means. A multilayer molding characterized in that the passage of the first resin material led between the outer nozzle and the inner nozzle is blocked, and the inner nozzle can apply injection holding pressure to the second resin material. Body injection molding machine.