JP3277313B2 - Nozzle for sandwich molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called sandwich molding nozzle in which the cross section of a molded product comprises a skin layer and a core layer.

[0002]

2. Description of the Related Art A conventional apparatus of an injection molding machine used for this type of sandwich molding will be described with reference to FIG. 3. A nozzle 1 has a nozzle hole 2 for injecting a resin into a mold cavity (not shown). Injection device for skin layer 3 concentric with 2
A space 5 is formed between the large-diameter portion slidably fitted to the inner diameter surface of the space and the inner diameter surface of the space in the space where the molten resin is introduced through the injection port 4, A skin-side needle 6 composed of a small-diameter portion into which the nozzle hole 2 can be opened and closed, and a molten resin from a core layer injection device 7 concentric with the skin-side needle 6 are introduced through an inlet 8. A large-diameter portion having a space provided with an opening 9 communicating with the space portion of the skin-side needle 6 and the nozzle hole 2, and a large-diameter portion slidably fitted to the inner diameter surface of the gap portion and an inner-diameter surface of the gap portion. And a core-side needle 11 composed of a small-diameter portion that fits openably and closably the opening 9 communicating with the space portion of the skin-side needle 6 and the nozzle hole 2. 6 and needle 11 are connected to hydraulic cylinders 12 and 13, respectively. It is adapted to advance and retreat in Rijiku direction.

[0003]

However, there are the following problems. 1. When the needle 6 and the needle 11 of the nozzle 1 are closing the nozzle hole 2 and the opening 9 respectively, the hydraulic cylinders 13 and 12 push the needle 6 and the needle 11 with the resin pressure so as not to open the nozzle hole 2 and the opening 9 respectively. In particular, since the skin-side needle 6 becomes large and the hydraulic cylinder 13 also becomes large in diameter, the injection devices 3 and 7
And the space between them becomes large, and the entire machine becomes large. 2. 2 The operating hydraulic cylinder 12 for operating the hydraulic cylinder 13 and the core side needle 11 of the skin-side needle 6
It becomes complicated by a heavy structure, if there is such as a resin leakage, decomposition, cleaning is troublesome. 3. To reduce the pressure loss of the resin in the nozzle 1, it is desired to make the nozzle length L as short as possible. However, the interval between the injection devices 3 and 7 is too wide, and the barrel head 14 becomes large, causing interference with the fixed die plate 15. However, since the portion A indicated by oblique lines must be deleted, the strength of the fixed die plate 15 is reduced, and the processing is complicated and the cost is increased. 4. The overall structure is complex and costly. 5. When a general injection molding machine is modified for sandwich molding for the reasons described in the above items 1 to 4, all members on the frame need to be replaced, and a large amount of cost is required.

[0004] It is an object of the present invention to eliminate the aforementioned disadvantages and to reduce the distance between two injection devices so that a general injection molding machine can be easily modified for sandwich molding. It is to provide a nozzle.

[0005]

According to the present invention, there is provided a first injection device for injecting a first resin, a second injection device for injecting a second resin, In a sandwich molding nozzle for injecting the second resin into the mold cavity simultaneously or by switching, a barrel head attached to a tip of one of the heating barrels of the first and second injection devices; attached to the tip of the barrel head, and having a first and second resin inlet, a nozzle body having a downstream diameter of the hole according to the nozzle hole in the large diameter upstream side in the axial section, outer peripheral in stepped consisting small diameter portion forming the first gap between the large diameter portion and DoFutoshi径hole, the resin passage in the interior has a central tip portion opening to be fitted into the hole of the large diameter of the nozzle body A hollow body with a bottom Is fixed to the main body, and wherein a first needle having a first groove communicating between said first resin inlet and the first gap in the large diameter portion, the resin path in the hollow portion the bottom of the first needle A small-diameter portion that fits openably and closably into the opening and forms a second gap between the first needle and the inner diameter surface on the bottom side of the hollow portion, and the inside of the hollow portion entrance side of the first needle. br /> with, slidably fitted to diameter surface, said second resin inlet and the actual shaft in the stepped consisting large diameter portion having a second groove communicating between the second gap Wherein the rear end of the large diameter portion is slidably slidable in a second needle connected to a drive source for opening and closing the resin path opening at the bottom of the hollow portion of the first needle and a small diameter hole of the nozzle body. And the inside of the first gap and
And the resin path opening at the bottom of the hollow of the first needle and the nozzle
A resin path communicating with the hole penetrates, and the opening and closing drive source
Is the tip of the first needle by another open / close drive source.
At the end of the first needle,
Valve for opening and closing between the first gap and the nozzle hole
And a nozzle for sandwich molding comprising:

[0006] This sandwich molding nozzle is provided with a first d.
Is the first injection device or the second injection device
It is fixed to the nozzle body provided at the tip, and the second
Only the needle moves to the first needle at the bottom of the hollow portion of the first needle.
The opening and closing of the resin path opening for the second resin is performed, and the first resin
Opening and closing is performed by using an on-off valve provided on the tip side of the first needle.
This is performed at the tip of the first needle. this
For this reason, a conventional double-structured nozzle opening / closing system
No need for Linda, small space nozzle
be able to.

[0007]

When an embodiment of the present invention fitted with a nozzle on the core layer injection unit by 1 and 2 is a second injection device DETAILED DESCRIPTION OF THE INVENTION explained, 20 in nozzle body, a core layer It is fixed to a barrel head 22 attached to the tip of the injection device 21. As shown in FIG. 2, the shaft core of the nozzle body 20 has a large diameter D on the upstream side and a small diameter d1 on the downstream side.
It is provided with a hole, the outer periphery in the bore of the large diameter D forms a first gap 23 between the hole of the large diameter portion and a large diameter D fitted into the hole <br/> of DoFutoshi径D in stepped consisting small diameter portion, inside the hollow portion with a bottom whose tip has an opening 24 in the central portion, the rear end is secured by a nut 25 with receiving at surface B of the barrel f <br/> head 22 A first needle 26 is provided.

[0008] The skin layer resin supplied from the injection device for the first skin layer is an injection device, not shown in the large diameter portion of the first needle 26 (first resin) 27 barrel F <br From the first resin injection port 28 in the first gap 23
Yes a first groove 29 is provided leading to considerably larger diameter when a force applied to the first needle 26 F4 Skin layer resin 27 is subjected when the resin pressure P1 F4 = πD ² P1 / 4, and the this with a hydraulic cylinder However, the disadvantage of using a large-diameter cylinder is compensated for by receiving it on the B side of the nozzle head 22.

A small-diameter portion in the hollow portion inside the first needle 26 has a distal end capable of opening and closing the opening 24 and forming a second gap 30 with the bottom hollow portion inside the first needle 26. And a second needle 31 having a large diameter portion slidably fitted in the inlet side hollow portion inside the first needle 26.
Is provided on the large diameter portion of the second needle 31. The core layer resin (second resin) supplied from the core layer injection device 21 is provided.
Fat) 32 to the second resin injection port 3 in the barrel head 22.
Second directing from 3 to the second gap 30 of the inside first needle 26
A groove 34 is provided.

An opening / closing valve 36 having a resin passage having an inner diameter d2 communicating with the nozzle hole 35 is provided in the small-diameter d1 hole of the nozzle body 20.
There Ri Ah provided to face the tip of the first needle 26, passes through and occlusion Previous <br/> SL resin passage of the inner diameter d2 of the skin layer resin 27 introduced into the first cavity 23 of the nozzle body 20 Is controlled.

[0011] will be considered where the resin pressure at the nozzle that put the present invention and its power relationship, the force F2 off valve 36 tries to open the resin pressure is F2 = π / 4 ·
(D1 ² -d2 ²⁾ P1 or P2 (provided that P2 is the pressure of the resin core layer resin 32). On the other hand the force F1-off valve 36 is attempting to close during the injection of the core layer resin 32 is on-off valve 36
Assuming the diameter d3 of the resin path on the exit side of F1, F1 = π / 4 · (d3
² -d2 ²⁾ P1 or P2 becomes, becomes F1 = F2 When d1 = d3, the force to close the force to open each other offset, the inlet and force from the outlet side to each other
Since there is no load, the on-off valve 36 can move forward and backward by the small-diameter hydraulic cylinder 37 and its rod 38.

The force F3 acting on the second needle 31 (for the core layer) is defined as the diameter d4 of the large diameter portion of the second needle 31.
That ^{when, F3 = πd4 2 · P2 /} 4 , and the with opening the opening 24 by the resin pressure of the first needle 26 the core layer resin 32 inside the second gap 30, the opening 24 by the hydraulic cylinder 39 and its rod 40 Is to be closed.

[0013]

As described above, the following effects are expected from the small-sized nozzle having the configuration in which the interval between the two injection devices is narrowed as described above. 1) In the upper or the side of the injection unit of a general injection molding machine simply by adding another other injection unit the ordinary injection molding machine can be easily modified for sandwich molding injection molding machine. 2) also be modified easily ordinary injection molding machine a sandwich molding injection molding machine to the opposite. 3) Simple structure, low cost, and easy maintenance.

[Brief description of the drawings]

It illustrates one example embodiment of the invention; FIG.

FIG. 2 is an explanatory diagram of a resin pressure of a nozzle of the present invention and a relationship between the pressure and the resin.

FIG. 3 is an explanatory view of a conventional sandwich molding nozzle.

[Explanation of symbols]

Injection apparatus for 20 nozzle body 21 core layer (second injection unit) 22 a barrel head 23 first gap 24 opening 25 nut 26 first needle 27 the skin layer resin (first resin) 28 first resin injection port 29 first 1 groove 30 second gap 31 second needle 32 resin for core layer (second resin) 33 second resin injection port 34 second groove 35 nozzle hole 36 on-off valve 37 hydraulic cylinder 38 rod 39 hydraulic cylinder 40 rod

Claims (1)

(57) [Claims] 1. A first injection device for injecting a first resin,
A second injection device for injecting the second resin, and a sandwich molding nozzle for injecting the first and second resins into the mold cavity simultaneously or by switching, wherein the first and second injection devices are A barrel head attached to the tip of one of the heating barrels, and a first and a second resin injection port attached to the tip of the barrel head, and a large diameter upstream side and a downstream side small-diameter portion forming a nozzle body having such small diameter holes in the nozzle hole, a first gap between the large diameter portion and DoFutoshi径holes outer periphery is fitted into the hole of the large diameter of the nozzle body With a step consisting of, the inside is a hollow body with a bottom opening the resin path in the center at the center, and the rear end is fixed to the nozzle body,
And that open the a first needle having a first groove communicating between said first resin inlet and the first gap in the large diameter portion, the resin path opening in the hollow portion the bottom of the first needle with fits, slidably in a hollow portion inlet side inner surface of the the small-diameter portion forming a second gap first needle between the hollow portion bottom in <br/> diameter surface of the first needle with fitted in, a solid shaft body in a stepped consisting large diameter portion having a second groove communicating between said second resin inlet and a second gap, after DoFutoshi diameter A second needle having an end communicating with a drive source for opening and closing the resin passage opening at the bottom of the hollow portion of the first needle ;
At the bottom of the hollow portion of the first gap and the first needle
The resin passage that connects the oil passage opening and the nozzle hole penetrates,
The front end is opened by an open / close drive source different from the open / close drive source.
The first needle is provided at the tip of the first needle so as to be able to contact and separate therefrom.
At the tip of the needle between the first gap and the nozzle hole
A sandwich forming nozzle having an on-off valve for opening and closing .