JPH06254923A - Injection device - Google Patents

Abstract

PURPOSE:To continuously supply a molding material to a cylinder chamber smoothly even when an injection cycle time is short, in an injection device wherein the molding material is preplasticized by a plunger type extrusion device and it is supplied to the cylinder chamber of an injection cylinder so as to inject the molding material from the cylinder chamber. CONSTITUTION:Two extrusion devices 44, 45 are provided for a common injection cylinder and valve means 62, 64 are provided for switching a supplying passage of molding material to the injection cylinder from the extrusion devices 44, 45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device in an injection molding device, and more particularly to an injection device provided with an extrusion device for pre-plasticizing a molding material and supplying it to an injection cylinder.

[0002]

2. Description of the Related Art As shown in FIG. 5, an injection molding apparatus for injecting a molding material inside an injection cylinder 100 from a tip nozzle portion 102 into a cavity of a molding die and molding it into a predetermined shape in the cavity. Is widely used as a molding device for rubber, resin, etc. As a kind of this injection molding apparatus, the injection cylinder 1 is prepared by pre-plasticizing the molding material.
Some of them are equipped with an extruding device for feeding the inside.

As shown in FIG. 5, the extruder 110 incorporates a screw 110 inside the extruder cylinder 108, and a screw pre-plast for pushing the molding material toward the injection cylinder 100 by the rotation of the screw 110. Type extruding device 106, and a plunger pre-plast type extruding device of a type in which a plunger is built in the extruding cylinder and the molding material is extruded toward the injection cylinder 100 by the forward movement of the plunger.

[0004]

In the case of the screw type extruder 106, since the molding material is plasticized by the rotation of the screw 110 and continuously extruded, when the injection cycle time in the injection cylinder 100 is short, that is, Injection cylinder 10 even when injection is performed in a fast cycle
A continuous supply of molding material to 0 is possible.

However, in the case where the extrusion device is the plunger pre-plaster system and the injection device itself (injection cylinder) is the plunger injection device, since the material processing is batch processing, one batch is processed and then the next batch processing is performed. As a result, there is a problem that continuous operation may not be possible.

[0006]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving such a problem, and its gist is to preplasticize a molding material by an extruder and then supply the molding material into an injection cylinder. In addition, in an injection device configured to inject the molding material in the injection cylinder from the nozzle portion at the tip toward the cavity of the molding die, a plurality of the extrusion devices are provided for a common injection cylinder, and the extruders are provided. Is provided with valve means for switching the supply passage of the molding material to the injection cylinder.

[0007]

As described above, according to the present invention, a plurality of extruders are provided for a common injection cylinder, and valve means for switching the supply passage of the molding material from these extruders is provided. According to the invention, even when the plunger type is used as the extrusion device, and also when the injection cycle time in the injection cylinder is short,
This can be easily handled by alternately supplying the molding material from the plurality of extruders to the injection cylinder, and continuous injection molding is possible.

Alternatively, even when the injection cycle time is long and continuous production is possible even with a single extruder, the use of a plurality of extruders facilitates the switching of the molding material.

While the extrusion material is being extruded and supplied by one extruding device, the other extruding device can be cleaned and inspected, and the extruding material can be quickly switched. is there. The switching of the molding material includes not only the case of different materials and types but also the case of different colors.

Alternatively, even when the same molding material is supplied to the injection cylinder, the length of each extruder can be shortened by providing a plurality of extruders.
The advantage is that the entire injection device can be made compact.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, reference numeral 20 denotes an injection device, which includes an injection cylinder main body 22, and the injection cylinder main body 22 is provided with a plurality of cylinder chambers 24.

An injection plunger 26 corresponding to each cylinder chamber 24 is held by a common holding block 28, and is connected to a plunger driving cylinder 30 via the holding block 28.

The plunger drive cylinder 30 includes a sliding body 32.
Further, the slide body 32 is connected to the injection cylinder body 22 via a rod 34, and they are supported by a rail 36 provided on the frame 12 by a drive cylinder 38 attached to the slide body 32. Under the guidance, it can be moved back and forth in the horizontal direction in the figure. The drive cylinder 38 has a cylinder body with a sliding body 3
2 and the rod 40 is fixed to the block 42 whose position is fixed.

On the upper side and the lower side of the injection cylinder body 22, there are provided one pushing device 44 and one pushing device 45, respectively. These extruding devices 44 and 45 preliminarily plasticize a molding material and supply it to the cylinder chamber 24. The extruding cylinder main body 46 and an extruding plunger 48 fitted inside the extruding cylinder main body 46.
And a material injection opening 50 provided on the tube wall of the extrusion cylinder body 46 and a plunger drive cylinder 52 for pushing out the extrusion plunger.

In these extrusion devices 44 and 45, the tip end portion of the extrusion cylinder body 46 is connected to the injection cylinder body 22 via a connection block 54 as shown in FIG. Moves back and forth in the left-right direction in the figure together with 22.

The injection cylinder body 22 has a structure shown in FIG.
As shown in (A), an injection passage 58 for guiding the molding material in each cylinder chamber 24 to a nozzle portion 56 provided corresponding to the molding material and the extrusion device 44 or 45 is extruded. Introducing passages 59, 60 for guiding the molding material to the respective cylinder chambers 24 are provided, and the valve bodies 62, 6 are provided at the connecting portions between the injection passages 58 and the introducing passages 59, 60.
4 are provided.

The connection block 54 is provided with a distribution chamber 66 for distributing the extruded molding material to the respective introduction passages 59 or 60 as shown in FIG. 2B, and the connection block 54 is also provided. A block 70 having a throttle portion 68 for equalizing the distribution of the molding material from the distribution chamber 66 to the respective introduction passages 59 or 60 is interposed between the injection cylinder body 22 and the injection cylinder body 22.

As shown in FIG. 3, the valve bodies 62 and 64 communicate with the first passage 72 for communicating the cylinder chambers 24 with the injection passage 58 and the introduction passage 59 or 60 with the cylinder chamber 24. A plurality of second passages 74 are provided at different axial positions corresponding to the number of cylinder chambers 24, and one of these two types of passages 72, 74 is fixed to the side surface of the injection cylinder body 22. By axial movement of the valve bodies 62, 64 by the valve drive cylinder 76, the valve drive cylinder 76 can be selectively positioned at a position facing the cylinder chamber 24 and the injection passage 58.

Next, the operation of this apparatus will be described. Figure 3 (B)
As shown in (a), the valve bodies 62 and 64 are positioned so that the upper extruding device 44 and the respective cylinder chambers 24 communicate with each other, and the molding material is ejected from the extruding device 44 into the respective cylinder chambers 24.
Supply to.

At this time, the molding material extruded from the extrusion device 44 first flows into the distribution chamber 66, passes through the narrowed portion 68 and reaches the respective introduction passages 59, and further passes through these introduction passages 59 to the respective cylinder chambers. It is sent in 24. Then, by the action of the narrowed portion 68, the molding material is transferred to each cylinder chamber 2
It is sent into 4 with a uniform inflow.

In this way, the molding material is supplied to each cylinder chamber 24, and the injection cylinder body 22 is advanced rightward in the figure as shown in FIGS. 4 (A) and 4 (B).

On the other hand, when the injection of the molding material into the cylinder chamber 24 is completed, the valve body 62 is moved to the cylinder chamber 24 and the injection passage 58.
And a plurality of injection plungers 26 are simultaneously moved forward by the plunger driving cylinder 30 to move the molding material in each cylinder chamber 24 into a plurality of cavities of a corresponding number in the molding die. Direct injection through each injection part.

On the other hand, the extrusion device 44 in which the molding material is supplied to the cylinder chamber 24 by the extrusion of the extrusion plunger 48.
When the extrusion plunger 48 is retracted and the molding material is continuously extruded, but the extrusion of the molding material from the extrusion device 44 cannot catch up with the ejection material injection / molding cycle due to the ejection of the injection plunger 26, In the apparatus of this example, the lower extrusion device 4 with respect to each cylinder chamber 24
The molding material is supplied from 5.

That is, the positions of the valve bodies 62 and 64 are shown in FIG. 3 (B).
After switching to the state of (b), the molding material is supplied from the lower extruding device 45 to the cylinder chamber 24, the valve bodies 62 and 64 are continuously switched to the state of FIG. The injection / molding operation is performed.

As described above, in the case of the apparatus of this example, the molding material can be alternately supplied from the upper and lower extrusion devices 44 or 45 to the cylinder chamber 24, and therefore, when the injection / molding cycle time is short. Can handle this,
Molded products can be continuously produced.

The apparatus of this example does not necessarily consist of a set of extruders 4.
It is not necessary to alternately supply the molding material to the cylinder chambers 24 and 45, and when the molding cycle time is long to some extent, one of the extrusion devices 44 or 4
It is possible to supply the molding material by using only No. 5 and during this, the other extruding device 45 or 44 can be cleaned, inspected, prepared for the extruding operation, and the like.

Therefore, when molding various kinds of molded products with different colors or different kinds of materials, there is an advantage that the switching can be performed quickly and the time for switching can be shortened.

Further, in the case of injection molding the same material, if the two extruders 44 and 45 are used, the capacity of each of the extruders 44 and 45 can be reduced, whereby the length (stroke) of the extruder cylinder can be reduced. It has the advantage that it can be shortened and the injection device can be made compact.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, the present invention is highly effective when applied to an injection device equipped with a plunger type extrusion device that supplies the molding material intermittently, but in some cases, it may be applied to an injection device equipped with a screw type extrusion device. It is also possible to apply. Even in this case, by switching the extrusion of the molding material between a plurality of extrusion devices, there is an advantage that the time for setup change can be shortened when molding different materials.

In addition to the above, the present invention can be applied to an injection device of a single normal mode having a single cylinder chamber and various other injection devices. It can be configured in a modified form.

[Brief description of drawings]

FIG. 1 is a partially cutaway view of an injection molding device including an injection device according to an embodiment of the present invention.

FIG. 2 is a view of a connecting portion between an injection cylinder body and an extrusion device, a valve body for switching a flow path, and a peripheral portion in the same apparatus.

FIG. 3 is an explanatory view of the operation of the valve body in FIG.

FIG. 4 is an operation explanatory view of the injection molding apparatus shown in FIGS.

FIG. 5 is a diagram showing an example of a conventional injection device.

[Explanation of symbols]

 20 Injection Device 22 Injection Cylinder Body 24 Cylinder Chamber 26 Injection Plunger 30 Plunger Drive Cylinder 44,45 Extrusion Device 56 Nozzle Part 58 Injection Passage 59,60 Introduction Passage 62,64 Valve Body 68 Throttling Part

Claims (1)

[Claims] 1. A molding material is pre-plasticized by an extruder and then supplied into an injection cylinder, and the molding material in the injection cylinder is injected from a nozzle portion at a tip toward a cavity of a molding die. In the injection device formed, a plurality of the above-mentioned extrusion devices are provided for a common injection cylinder, and a valve means for switching a supply passage of the molding material from these extruders to the injection cylinder is provided.