JPH0699460A - Injection molding apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure that the injection molding raw material is melted,
In addition, it should be possible to arbitrarily select the amount of molten raw material accumulated. [Constitution] Raw material supply port 13 at the rear end of the screw 4
Is connected to a cylindrical raw material supply member 12 formed along the axis, and the raw material hopper 10 is connected so as to communicate with the raw material supply port 13.
To arrange. As a result, even if the screw 4 moves backward, the raw material 6 in the raw material hopper 10 can always be supplied to the rear end portion of the screw 4 through the raw material supply port 13.
The melting zone L ₁ of the screw 4 can be maintained as it is. As a result, the raw material supply member 12 is connected to the hydraulic motor 3
By rotating with, the raw materials are surely melted, stirred and kneaded, and the occurrence of defective products is surely prevented.
The accumulated amount of the injection raw material 601 can be arbitrarily selected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus capable of reliably melting an injection molding raw material and arbitrarily selecting the amount of the molten raw material accumulated.

[0002]

2. Description of the Related Art The outline of an injection molding apparatus will be described with reference to FIG. The injection molding machine has a screw 4 in the barrel 1.
Is rotatably mounted and is movable back and forth. Among them, the barrel 1 is provided with a heater (not shown), and the screw 4 feeds the raw material to the front only in the feed zone Z ₁ , which gives the raw material a strong compression / shearing force to positively feed the raw material. A compression zone Z ₂ to be melted and a metering zone Z ₃ to completely and uniformly melt the molten material by further stirring and kneading.
The length is secured.

[0003] Then, the raw materials 6 supplied from the raw material hopper 10 is gradually melted by being heated by a heater provided in the barrel 1 while being fed in the feed zone Z _1, subsequently gradually strong compression and shearing forces by compression zone Z ₂ The raw material, which has been received and is further melted by being heated by a heater, is substantially kneaded and kneaded in the metering zone Z ₃ to be completely and uniformly melted and accumulated in the tip portion of the barrel 1.

In this series of melting process of the raw material, the feed zone Z ₁ , the compression zone Z ₂ and the metering zone Z ₃ are not clearly defined, and the length of each zone or the residence time of the raw material is As a result, the above activities in each zone are carried out naturally. Therefore, if the length of each zone or the retention time of the raw material, especially the length of the feed zone Z ₁ or the retention time of the raw material is not satisfied and the raw material in the feed zone Z ₁ is insufficiently melted, the subsequent compression This is an important technique for the length of the feed zone Z ₁ because it affects the melting and stirring and kneading of the raw materials in the zone Z ₂ and the metering zone Z ₃ and makes it impossible to melt the raw materials completely and uniformly. Has an inherent meaning.

The conventional injection molding apparatus will be described with reference to FIG. 7. The raw material hopper 10 is disposed at the rear end of the screw 4, that is, at the inlet of the feed zone Z _1. The rotary shaft 9 is connected to the rear end of the rotary shaft 9, and the hydraulic motor 3 is connected to the rear end of the rotary shaft 9 to rotate the screw 4. On the other hand, the forward / backward movement of the screw 4 is performed by an injection cylinder 7 provided in parallel with the screw 4. The same model as this injection molding machine is actually Kaihei 3-1098
It is also disclosed in Japanese Patent No. 22.

Then, the injection molding is performed as shown in FIG. That is, in the step (a) of FIG. 7, the raw material 2 in the hopper 10 is fed from the opening 2 to the inlet of the feed zone Z ₁ of the screw 4, and the raw material 6 thus fed is fed into the feed zone Z ₁ While being passed through the compression zone Z ₂ and the metering zone Z _3, they are melted, stirred and kneaded while being heated by a heater provided in the barrel 1. In this way, melting, stirring,
The kneaded raw material is accumulated as injection material 601 at the tip of the barrel 1 while pushing back the screw 4 as shown in (b). The injection material 601 is accumulated in an amount corresponding to the volume of the cavity 11 formed by the mold 8. When the accumulated amount reaches a predetermined amount, as shown in (c), the injection cylinder 7 is operated and the screw 4 is moved forward, whereby the accumulated injection material 601 is pushed out by the screw head 5 and the cavity It is injected into 11 and one step of injection is completed.

[0007]

SUMMARY OF THE INVENTION In the above conventional example,
The raw material hopper 10 is disposed is located at the entrance portion of the feed zone Z _1, so had to be introduced raw material 6 to the inlet of the feed zone Z ₁ has a problem to be improved as follows.

That is, as shown in FIG.
Since the screw 4 is pushed back by the injection material 601 which is agitated / kneaded and accumulated, the feed zone Z ₁ is gradually shortened as the amount of accumulation increases, and finally becomes Z ₁ ′. As described above, when the feed zone Z ₁ is gradually shortened, the effective melting zone L ₃ of the screw 4 is shortened, and melting of the raw materials in the compression zone Z ₂ and stirring and mixing in the metering zone Z ₃ become insufficient, There is a problem that defective products occur in injection molded products.

Further, in order to avoid such a problem, the length of the feed zone Z ₁ is set to the compression zone Z 1.
Melting of raw materials in ₂ and metering zone Z ₃
The amount of retreat of the screw 4 may be limited to such an extent that it does not affect the stirring and kneading in step 1. However, limiting the amount of retreat of the screw 4 in this way means that the maximum measuring stroke of the screw 4 with respect to the melting zone L ₁ is increased. The L ₂ is limited, and the amount of the injection material 601 accumulated is limited. Therefore, it becomes impossible to injection-mold a product having a capacity equal to or more than the accumulated amount, and the products that can be injection-molded are limited. There is a problem in terms of economic efficiency and productivity in the sex product.

Further, the retreat amount of the screw 4 is limited to such an extent that the length of the feed zone Z ₁ does not affect the melting of the raw materials in the compression zone Z ₂ and the stirring and kneading in the metering zone Z _3. However, it is difficult to satisfy all the conditions such as the raw material quality, the external conditions such as the temperature condition of the heater provided in the barrel 1 and the relationship between the accumulated amount and the screw retracted amount with respect to the product capacity, There are problems with product quality and productivity.

According to the present invention, the relationship among the feed zone Z ₁ , the compression zone Z ₂ and the metering zone Z ₃ is kept constant to ensure that the injection molding raw material is melted, and the amount of the molten raw material accumulated is arbitrarily set. The present invention provides an injection molding apparatus that solves all the above problems by making selections possible.

[0012]

Means for Solving the Problems According to the present invention for solving the above-mentioned problems, in an injection molding apparatus in which a screw is provided in a barrel so as to rotate and advance and retreat, a raw material is supplied to the rear end of the screw. Connecting a cylindrical raw material supply member formed along the shaft center, the raw material hopper is arranged so as to communicate with the raw material supply port of the raw material supply member, and the raw material is fed from the rear side of the raw material hopper. The raw material supply member is provided with a supply means for supplying the raw material to the screw side through the raw material supply port.

[0013]

Since the present invention is constructed in this way, it has the following actions. That is, a cylindrical raw material supply member having a raw material supply port formed along the axial center was connected to the rear end of the screw, and a raw material hopper was arranged so as to communicate with the raw material supply port of this raw material supply member. Therefore, even if the screw moves backward, the raw material in the raw material hopper can be constantly supplied to the rear end portion of the screw through the raw material supply port. Since the rotation drive device for rotating the raw material supply member is provided, the screw is rotated through the raw material supply member while always supplying the raw material in the raw material hopper to the rear end portion of the screw even when the screw is retracted. It will be possible.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, which is a longitudinal sectional view of the entire injection molding apparatus, a screw 4 is provided inside the barrel 1 so as to be rotatable and movable back and forth, and a raw material supply member is provided at a rear end portion of the screw 4. 12 are connected. A shaft 301 of the hydraulic motor 3 is connected to the other end of the raw material supply member 12, and a coupling is connected to the other end of the shaft 301 of the hydraulic motor 3.
A raw material hopper 10 is provided via 16. As a result, the screw 4 is rotated by the hydraulic motor 3 via the raw material supply member 12. An injection cylinder 7 has a rod 701 fixed to a shaft 301 of the hydraulic motor 3 via a fixing member 702, and a screw 4
Is driven by the injection cylinder 7.

Raw material supply member 12 and shaft 3 of hydraulic motor 3
Raw material supply ports 13 and 14 are formed in the center of 01, respectively, and the raw material supply member 12 and the shaft 301 of the hydraulic motor 3 are substantially hollow cylindrical. The connection between the rear end portion of the screw 4 and the raw material supply member 12 is shown in an enlarged view in FIG. 2, and the discharge port 17 formed at the rear end portion of the screw 4 and the raw material supply member 12 Port 13
Raw material supply port
The raw material transferred inside 13 is transferred to the discharge port 17 as shown by arrow A.

In FIG. 3, which is an enlarged view of the coupling 16, the shaft 301 of the hydraulic motor 3 and the coupling 16 are connected via a bearing 18, and the shaft 301 rotates and the coupling 16 remains stationary. It is supposed to be maintained.
Reference numeral 19 is a packing, and 20 is a dust seal for preventing dust from entering the raw material transferred through the raw material supply port 14. Reference numeral 15 denotes a screw feeder for forcibly supplying the raw material 6 in the raw material hopper 10 for forcibly supplying the raw material 6 into the raw material supply ports 13 and 14. The screw feeder 15 for forced supply of raw material shown in FIG. 1 has a length that fits within the range of the coupling 16, but as shown in FIG. 4, the screw feeder 15 extends from the coupling 16 to the entire range of raw material supply ports 13 and 14. It may be a long length. The length of the raw material forced-feeding screw feeder 15 is appropriately and selectively determined according to the properties of the raw material, and is detachable, so that the raw material forced-feeding screw feeder 15 can be replaced with the selected length. Has become. 151 is a motor for driving the screw feeder 15 for forced supply of raw material.

In the embodiment shown in FIGS. 1 and 4, the raw material supply port 14 is formed on the shaft 301 of the hydraulic motor 3.
As shown in FIG. 5, the hydraulic motor 3 provided with a normal shaft 302 having no raw material supply port is used, and as shown in FIG. 6, the rotation of the hydraulic motor 3 is controlled by the gears 21 and 22. It may be transmitted to the supply member 12. This allows the use of normal (commercially available) hydraulic motors. In FIG. 5, the raw material supply member 12 and the coupling 16 are connected by using the connecting member 121, but the raw material supply member 12 may be directly connected to the coupling 16 by omitting the connecting member 121. Good.

The operation of the present embodiment thus constructed will be described below. In FIG. 1, since the raw material supply member 12 having the raw material supply port 13 formed at the rear end portion of the screw 4 is connected, the raw material 6 in the raw material hopper 10 is fed by the raw material forced supply screw feeder 15 to the raw material supply port. It becomes possible to supply to the discharge port 17 shown in FIG. 2 through 13 and 14. Since the raw material supply member 12 is connected to the shaft 301 of the hydraulic motor 3, the screw 4 is rotated by the hydraulic motor 3 while the raw material 6 is supplied to the rear end portion of the screw 4 by the screw feeder 15 for forced supply of raw material. It is possible to let In addition, as shown in FIG.
The raw material supply member 12 is rotated through the screw 4 and the screw 4
Screw feeder for forcibly supplying raw materials even when rotating
It becomes possible to rotate the screw 4 by the hydraulic motor 3 while supplying the raw material 6 to the rear end portion of the screw 4 by 15.

As described above, the raw material 6 supplied to the rear end of the screw 4 while rotating the screw 4 by the hydraulic motor 3 is transferred by the screw 4 while being heated by the heater (not shown) provided in the barrel 1. Melt,
Stirring and kneading are performed, and the molten, stirred, and kneaded injection raw material 601 is accumulated at the tip of the barrel 1 as shown in FIG. 4 is pushed and moves backward.

In this way, even if the screw 4 is pushed back by the accumulated injection raw material 601, the raw material 6 is supplied to the rear end portion of the screw 4, so that the melting zone L ₁ of the screw 4 is maintained as it is. Therefore, the relationship among the feed zone Z ₁ , the compression zone Z ₂ , and the metering zone Z ₃ (see FIG. 7) can be maintained, and melting, stirring, and kneading by the screw 4 can be reliably performed. Further, as described above, the feed zone Z ₁ and the compression zone Z irrespective of the backward movement amount of the screw 4.
₂ , the relationship between the metering zone Z ₃ is maintained, and melting, stirring, and kneading with the screw 4 can be reliably performed, so that the maximum measuring stroke L ₂ is not limited and an arbitrary stroke can be obtained. Will be possible. Therefore, the size of the injection molded product (capacity of the cavity)
By adjusting or selecting the length L ₄ of the barrel 1 and the stroke S of the injection cylinder 7 in accordance with the above, it becomes possible to eliminate the limitation on the size of the injection molded product.

[0021]

As described in detail above, according to the present invention, a cylindrical raw material supply member having a raw material supply port formed along the axial center is connected to the rear end portion of the screw, and the raw material of this raw material supply member is connected. Since the raw material hopper is arranged so as to communicate with the supply port, even if the screw moves backward, the raw material in the raw material hopper can always be supplied to the rear end of the screw through the raw material supply port, and the screw melts. You can keep the zone as it is. Since the rotation drive device for rotating the raw material supply member is provided, the screw is rotated through the raw material supply member while always supplying the raw material in the raw material hopper to the rear end portion of the screw even when the screw is retracted. It is possible to reliably melt, stir and knead the raw materials, to reliably prevent the generation of defective products, and it is possible to arbitrarily select the accumulated amount of injection raw materials, so there is no limit to the size of injection molded products. It is possible to improve economic efficiency and productivity.

[Brief description of drawings]

FIG. 1 is a view showing an injection step in a longitudinal section of an embodiment of the present invention, (a) showing a state before accumulating injection raw materials, and (b) showing a completed accumulation state. FIG.

FIG. 2 is a vertical cross-sectional view showing a partially enlarged view of a connecting portion between a screw and a raw material supply member in FIG.

FIG. 3 is an enlarged vertical sectional view of the coupling shown in FIG.

FIG. 4 is a vertical cross-sectional view showing another embodiment of the screw feeder for forced supply of raw material.

FIG. 5 is a vertical cross-sectional view showing another embodiment of the rotation driving mechanism of the raw material supply member.

6 is a view on arrow XX in FIG.

FIG. 7 is a view showing an injection step in a longitudinal section of a conventional example, in which (a) is a view showing a state before accumulating injection raw material;
(B) is a diagram showing a state where the accumulation is completed, and (C) is a diagram showing an injection completed state.

[Explanation of sign]

 1 barrel 3 hydraulic motor 4 screw 6 raw material 601 injection raw material 7 injection cylinder 10 raw material hopper 12 raw material supply member 13 raw material supply port 14 raw material supply port

Claims (1)

[Claims] 1. An injection molding apparatus comprising a barrel in which a screw is rotatable and movable back and forth, and a cylindrical raw material supply member having a raw material supply port formed along an axial center is connected to a rear end portion of the screw. Then, a raw material hopper is arranged so as to communicate with the raw material supply port of the raw material supply member, and a supply means for supplying raw material from the rear side of the raw material hopper to the screw side through the raw material supply port is used to supply the raw material. An injection molding device, which is provided on a member.