JPH115231A - Nozzle for sandwich molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the easy discharge of a leaking molten resin by contriving the arrangement of a peripheral groove groove formed on the outer peripheral face of an inner nozzle, in a sandwich injection molding made up of a core layer and a skin layer in the cross section of the molding when a plastic molded. SOLUTION: In the nozzle for sandwich molding equipped with an outer nozzle 31, an inner nozzle 32 and a needle 33, a spiral peripheral groove 51 extending from an upper position to the side of a second resin injection hole to a lower position to the side of a drive source lateral end part, on the second peripheral face of the inner nozzle 32, is formed between a position in which the second resin injection hole 35 is formed and the drive source lateral end part in the inner nozzle 32. At the same time, a down directed resin bleeder 52 which communicates with the peripheral groove 51 and is open to the outside is formed between the positions described.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sandwich molding nozzle suitable for use in sandwich injection molding of a molded article having a core layer and a skin layer in plastic molding.

[0002]

2. Description of the Related Art Conventionally, various nozzles for sandwich molding in sandwich injection molding have been developed.
One example is disclosed in Japanese Utility Model Publication No. 7-42677. Hereinafter, the sandwich forming nozzle disclosed in this publication will be described.

FIG. 4 is a cross-sectional plan view showing a main part of a conventional side-switch molding nozzle in a sandwich injection molding machine, partially cut away. In FIG. 4, reference numeral 1 denotes an outer nozzle. The outer nozzle 1 has a first injection port 1a for injecting a first resin at a distal end, and is configured to be hollow. The outer nozzle 1 has a first resin injection hole 4 communicating with a first injection device (not shown) and a second resin injection hole 5 communicating with a second injection device (not shown). Is provided.

Reference numeral 2 denotes an inner nozzle. The inner nozzle 2 is slidably fitted within the inner diameter surface of the outer nozzle 1 by being driven by a driving source (driving device; not shown, the same applies hereinafter). The inner nozzle 2 is also hollow. Specifically, it slides in the direction of the left and right arrows (see A in FIG. 4), and has a tip for injecting the second resin so as to be aligned with the first injection port 1a. A second injection port (discharge port) 2a is provided. In FIG. 4, the inner nozzle 2 slides to the left, and its tip is the outer nozzle 1.
2 shows a state in which the abutment is in contact with the inner surface of the distal end portion. In the figure, reference numeral 2c denotes a drive source side end of the inner nozzle 2.

Further, a gap 6 is formed between the inner diameter surface of the outer nozzle 1 and the outer diameter surface near the tip of the inner nozzle 2, and the gap 6 and the first resin injection hole 4 are formed. Are communicated by the resin passage 8. That is, when the first resin is injected into the mold,
The first resin injected from the first resin injection hole 4 flows into the cavity 6 through the resin passage 8, and the first injection port 1a
It is designed to be ejected through. In this case, the inner nozzle 2 shown in FIG. 4 is moved rightward.

In the figure, reference numeral 11 denotes the outer nozzle 1.
The circumferential groove 11 is provided on the inner diameter surface of the inner nozzle 2 and communicates with a resin vent hole 12 which is provided on the outer nozzle 1 and opens downward on the outside. They are arranged at right angles. The first resin leaking from the sliding gap between the outer nozzle 1 and the inner nozzle 2 is discharged by the peripheral groove 11 and the resin vent hole 12.

Further, the peripheral groove 11 and the resin vent hole 12 are formed at the position where the first resin injection hole 4 and the second resin injection hole 5 are formed and at the drive source side end 1 c of the outer nozzle 1.
(Hereinafter, may be simply referred to as an end 1c). In the drawing, reference numeral 1b denotes a connecting portion to the machine frame. In the figure, reference numeral 13 denotes a circumferential groove provided on the inner diameter surface of the inner nozzle 2, and the circumferential groove 13 is provided on the outer nozzle 1 through a communication hole 14 provided in the diameter direction of the inner nozzle 2. The peripheral groove 13 is also arranged at right angles to the axis of the inner nozzle 2.
And, by these peripheral groove 13 and communication hole 14,
The second resin leaking from the sliding gap between the inner nozzle 2 and the needle 3 is discharged.

Further, these peripheral grooves 13, communication holes 14 and resin removal holes 15 are formed with first resin injection holes 4 and second resin injection holes 5, similarly to the above-described peripheral grooves 11 and resin removal holes 12. And the drive source side end 1 c of the outer nozzle 1. Reference numeral 16 denotes an auxiliary peripheral groove provided on the inner diameter surface of the outer nozzle 1. Reference numeral 3 denotes a needle. The needle 3 is slidably fitted into the inner diameter surface of the inner nozzle 2 by being driven by a driving source. A gap 7 is provided between the nozzle 2 and the inner diameter surface.
Are formed. The gap 7 and the second resin injection hole 5 are communicated with the resin passage 9 via a resin communication hole 10 provided in the diameter direction of the inner nozzle 2. FIG. 4 shows a state in which the needle 3 slides to the left and the tip of the needle 3 contacts the inner surface of the tip of the inner nozzle 2.

With such a configuration, the sandwich molding nozzle shown in FIG. 4 is configured such that the molten resin (the first resin and the second resin) is filled with the respective injection holes (the first resin injection holes 4 and 4).
When injected from the second resin injection hole 5), most of the first resin flows toward the first injection port 1a, but part of the first resin slides between the outer nozzle 1 and the inner nozzle 2. It leaks from the gap toward the end 1c of the outer nozzle 1. At this time, the leaked resin is accumulated in the circumferential groove 11 formed on the inner diameter surface of the outer nozzle 1.

Further, most of the second resin flows toward the second injection port 2a, but part of the second resin flows from the sliding gap between the inner nozzle 2 and the needle 3 to the end 2c of the inner nozzle 2. Leaks in the direction. Also in this case, the fluid is collected in the circumferential groove 13 formed on the inner diameter surface of the inner nozzle 2. After that, the first resin accumulated in the peripheral groove 11 flows downward through the resin removal hole 12 communicating with the peripheral groove 11 and is discharged, and the second resin accumulated in the peripheral groove 13 is Through the communication hole 14 communicating with the peripheral groove 13, the resin flows downward from the resin removal hole 15 and is discharged.

That is, the resin discharged downward from the resin drain holes 12 and 15 can be directly collected by dropping, and even when solidified, hangs down in the form of a rod or a band. By breaking off, the leaked resin can be removed.

[0012]

However, in such a conventional sandwich molding nozzle, the leakage of the resin from the drive source side end 1c is prevented by a circumferential groove 11 provided on the inner diameter surface of the outer nozzle 1. This is prevented by communicating with the resin vent hole 12 that opens downward from the outside. However, since the peripheral groove 11 is disposed at right angles to the axis of the inner nozzle 2, the peripheral groove 11 is accumulated in the peripheral groove 11. There is a problem that the pressing force for pushing out the resin in the direction of the resin removal hole 12 is insufficient, and the resin removal on the side (upper side of the inner nozzle 2) in the circumferential groove 11 away from the resin removal hole 12 cannot be performed sufficiently.

[0013] The present invention has been made in view of the above-mentioned problems, and by devising the arrangement of the circumferential grooves provided on the outer peripheral surface of the inner nozzle, the leaked molten resin can be easily discharged. It is an object of the present invention to provide a sandwich forming nozzle that can be used.

[0014]

In order to achieve the above object, a sandwich molding nozzle of the present invention has a first
A hollow outer nozzle having a first injection port for injecting the first resin, and a second injection port for injecting the second resin at the tip so as to be aligned with the first injection port. A hollow inner nozzle slidably fitted in the inner diameter surface of the outer nozzle by being driven by a first drive source; and the inner nozzle by being driven by a second drive source. A first resin is injected through a first resin injection hole that penetrates a side wall of the outer nozzle, and a second resin is injected into the outer resin. In a sandwich molding nozzle that is injected through a second resin injection hole penetrating the respective side walls of the nozzle and the inner nozzle, the position of the second resin injection hole in the inner nozzle and the drive position are determined. A helical wire extending from the upper position close to the second resin injection hole to the lower position close to the drive source side end on the outer peripheral surface of the inner nozzle between the power supply end and the power supply end. In addition to the above, a peripheral groove is formed, and a lower resin vent hole communicating with the peripheral groove and opening to the outside is provided in a lower portion of the outer nozzle (claim 1).

In this case, at least one of the width and the depth of the peripheral groove may be configured to gradually increase from the upper part to the lower part of the outer peripheral surface of the inner nozzle. In addition, a seal bush that slidably supports the inner nozzle is provided at an end of the outer nozzle on the drive source side, and a seal bush is provided between a position where the seal bush is disposed and a position where the second resin injection hole is formed. A groove can be provided (claim 3).

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a configuration of a sandwich molding nozzle according to an embodiment of the present invention. FIG. 1 is a cross-sectional plan view showing a main part of the nozzle, and FIG. FIG. 3 is an enlarged perspective view showing a main part thereof partially broken away.

As shown in FIG. 1, the sandwich molding nozzle according to the present embodiment includes a hollow outer nozzle 31 and a hollow inner nozzle 32 fitted in the inner diameter surface of the outer nozzle 31. The inner nozzle 32 is provided with a needle 33 fitted in the inner diameter surface thereof. Hereinafter, the configuration of each unit will be described in detail.

Specifically, the outer nozzle 31 has a first injection port (discharge port) 3 for injecting the first resin at the tip.
1a, the first resin is injected through a first resin injection hole 34 penetrating the side wall of the outer nozzle 31. Further, a gap portion 36 through which the first resin flows is formed between the inner circumferential surface of the outer nozzle 31 and the outer circumferential surface near the tip of the inner nozzle 32, and the gap portion 36 and the first resin are formed. The injection hole 34
They are communicated by a resin passage 38.

The first resin is placed in a mold (not shown,
In the following, the inner nozzle 32 slides rightward, the first resin flows into the gap 36 through the resin passage 38, and is injected through the first injection port 31a. It is supposed to be. Also, the inner nozzle 32
Has a second injection port 32a for injecting the second resin so that the second injection port can be aligned with the first injection port 31a, and is driven by a first drive source (not shown). Thus, the outer nozzle 31 is slidably fitted in the inner diameter surface. Then, the second resin is injected through the second resin injection holes 35 penetrating the respective side walls of the outer nozzle 31 and the inner nozzle 32.

Further, the needle 33 is slidably fitted in the inner diameter surface of the inner nozzle 32 by being driven by a second driving source (not shown).
A gap portion 37 through which the second resin flows is formed between the outer peripheral surface on the distal end side of the needle 33 and the inner peripheral surface of the inner nozzle 32. The gap 37 and the second resin injection hole 35 are communicated by the resin passage 39 and the communication hole 40.

Specifically, as shown in FIG. 3, the resin passage 39 is provided over a half circumference in the circumferential direction of the inner nozzle 32, and has two communicating holes provided vertically in the diameter direction. The (long hole) 40 communicates the gap 37 with the second resin injection hole 35. Then, when the second resin is injected into the mold, the inner nozzle 32 slides to the left as shown in FIG.
Flows through the resin passage 39 and the communication hole 40 into the cavity 37, and is injected through the second outlet 32a and the first outlet 31a.

Between the formation position of the second resin injection hole 35 in the inner nozzle 32 and the end on the drive source side, the second resin injection hole 3 is formed on the outer peripheral surface of the inner nozzle 32.
A helical winding groove (square groove) extending from an upper position closer to 5 to a lower position closer to the drive source side end (from one point at the upper side to the left and right toward one lower point). The peripheral groove 51 prevents the resin from leaking.

Specifically, the circumferential groove 51 is positioned between the position where the second resin injection hole 35 is formed and the position where the seal bush 53 provided at the drive source side end 31c is provided, as described later. It is provided between them. As shown in FIGS. 2 and 3, the width (see FIG. 3B) and depth (see FIG.
D) from the upper part (see A of FIGS. 2 and 3) of the outer peripheral surface of the inner nozzle 32 to the lower part (B of FIGS. 2 and 3).
(See FIG. 2), the cross-sectional area gradually increases about 1.5 to 2 times (the cross-sectional area increases from top to bottom). Specifically, as shown in FIGS. The circumferential groove 51 is formed in a helical shape of left and right windings approaching the drive source side by a length L.

Although the cross-sectional shape of the peripheral groove 51 is a square groove here, the cross-sectional shape is not limited to this, and other shapes may be used. Also, the width and depth of the peripheral groove 51 may be gradually increased so that at least one of the width and the depth of the peripheral groove 51 gradually increases from the upper part to the lower part of the outer peripheral surface of the inner nozzle 32. The rate of the gradual increase is not limited to this, and can be adjusted according to conditions such as the characteristics of the resin or the outer diameter of the inner nozzle 32.

Further, at the lower part of the outer nozzle 31,
A downward resin vent hole 52 which communicates with the peripheral groove 51 (communicates in FIG. 2B) and opens to the outside is provided. The resin accumulated in the peripheral groove 51 is discharged from the resin vent hole 52. Has become. In this manner, the circumferential groove 51 is not disposed at right angles to the axis of the inner nozzle 2,
Because it is arranged in a helical spiral from the upper part to the lower part, that is, it is arranged so that the flow distance is short at the upper part of the inner nozzle 2 and longer at the lower part (see FIG. 2). ), The resin pressure of the molten resin entering the circumferential groove 51 is higher in the upper part, and therefore, the molten resin is pushed in the circumferential direction of the inner nozzle 32 and easily discharged to the outside through the lower resin vent hole 52. You can do it.

A seal bush 53 for slidably supporting the inner nozzle 32 is provided at the drive source side end 31c of the outer nozzle 31 described above. Specifically, the seal bush 53 is made of a bearing alloy made of cast iron or a copper alloy, and is configured as a metal packing with a flange (a bush-shaped metal packing with a flange) attached by a plurality of bolts 54. .

The fitting gap between the seal bush 53 and the inner nozzle 32 is configured to be smaller than the fitting gap around the tip of the outer nozzle 31 and the inner nozzle 32.
By making the fitting gap between them both sufficiently smaller than the fitting gap of the general sliding portion of the outer nozzle 31 and the inner nozzle 32, a large flow resistance can be given to the molten resin, and the molten resin flows back in the axial direction. Resin (circumferential groove 5
1 to prevent the molten resin from entering the sliding gap on the drive source side again).

Further, in FIG. 1, reference numeral 32b denotes a flange portion of the inner nozzle 32.
Is provided at a drive source side end of the inner nozzle 32, and is a first hydraulic cylinder (not shown) serving as a first drive source.
It is to be connected to. Further, reference numeral 33a denotes a connecting portion, which is provided on the driving source side of the needle 33, and is a second hydraulic cylinder (not shown) which is a second driving source different from the above-described flange portion 32b. It is to be connected to. The outer diameter of the connecting portion 33a is slightly larger than the outer diameter of the needle 33, and the driving source side of the needle 33 is slidably inserted by a sealing bush 41 fitted to the inner nozzle 32. Airtightness is maintained. The sealing bush 41 is fitted from the drive source side to the front side of the resin injection hole 35 as shown in FIG.

As described above, since the flow resistance of the outer periphery of the needle 33 is increased by the sealing bush 41 fitted to the inner periphery of the inner nozzle 32, it is possible to prevent the molten resin from flowing back in the axial direction of the needle 33. You can do it. With the above configuration, when the first resin (molten resin) is injected, the present sandwich molding nozzle
By driving the first drive source and the second drive source,
The inner nozzle 32 and the needle 33 are retracted to the drive source side, and the first resin injected (injected) from the first resin injection hole 34 is injected into the mold from the first injection port 31a.

Thereafter, when the second resin (molten resin) is injected, the first drive source is driven to move the inner nozzle 32 forward as shown in FIG. The first injection port 31a of the first resin injected from the resin injection hole 34 is closed. In this state, by driving the second drive source, the needle 3
Retreat 3

The second resin is filled in the second resin injection hole 3.
5, the resin pressure in the resin passage 39 increases, and as a result, the second resin is in contact with the inner peripheral surface of the inner nozzle 32 communicating through the communication hole 40 with the needle 33.
It is injected into the mold through the second injection port 32a and the first injection port 31a through a gap 37 formed between the outer mold and the outer peripheral surface of the mold.

At this time, most of the second resin injected from the second resin injection hole 35 flows in the direction of the second injection port 32a. In some cases, the outer flow of the inner nozzle 32 flows backward toward the drive source side (seal bush 53 side).
The molten resin flowing backward enters the peripheral groove 51 provided on the drive source side with respect to the second resin injection hole 35, and the pressure drops to accumulate in the peripheral groove 51.

Thereafter, the molten resin accumulated in the peripheral groove 51 is pushed in the circumferential direction of the inner nozzle 32 and is discharged to the outside through a resin vent hole 52 below the inner nozzle 32. That is, since the circumferential groove 51 is inclined in the shape of a helical winding (since the flow distance is short at the upper portion and long at the lower portion), the resin pressure at the upper portion is higher, and the resin pressure at the lower portion is easily increased. Run out.

Further, the second resin injected from the second resin injection hole 35 tends to flow backward through the outer peripheral portion of the needle 33, but is fitted from the drive source side to the position of the second resin injection hole 35. Due to the mounted sealing bush 41, it flows to the second injection port 32a without flowing backward. As described above, according to the sandwich molding nozzle as one embodiment of the present invention, the peripheral groove 51 which is easy to flow in the circumferential direction of the inner nozzle 32 in the shape of a vine winding is provided, and the resin drainage communicating with the peripheral groove 51 is provided. Since it is provided with the holes 52, the molten resin that has flowed back can be easily discharged to the outside of the machine by a pressure difference, which can greatly contribute to the improvement of the performance of the present apparatus.

Further, since at least one of the width and the depth of the peripheral groove 51 is configured to gradually increase from the upper part to the lower part of the outer peripheral surface of the inner nozzle 32, the sectional area is the same. In addition, the molten resin can be easily discharged, and the discharge amount of the molten resin can be further increased by gradually increasing the width and the depth (cross-sectional area) of the peripheral groove 51.

Further, since the seal bush 53 is provided at the drive source side end 31c of the outer nozzle 31, the leakage of the molten resin can be prevented by the seal bush 53 in addition to the discharge of the molten resin by the circumferential groove 51. In this case, the operation of the inner nozzle 32 caused by the leakage of the resin can be hindered, and the time required for removing the solidified resin can be significantly reduced, so that there is an advantage that the production efficiency can be improved.

The flange portion 3 of the inner nozzle 32
Since the sealing bush 41 is provided in 2b, the leakage of the molten resin can be reliably prevented. In this case, the operation of the needle 33 caused by the leakage of the resin and the time required to remove the solidified resin are greatly reduced. Can be reduced. It should be noted that the present invention is not limited to this embodiment, and for example, it is also possible to apply the present invention to other plastic injection molding within a range not departing from the gist of the present invention, such as changing molding conditions and the like. You can expect to get the effect.

[0038]

As described above in detail, according to the sandwich molding nozzle of the present invention, there is provided a circumferential groove which is easy to flow in the circumferential direction of the inner nozzle in the form of a helical winding, and a resin drain which communicates with the circumferential groove. Since it is provided with holes, the molten resin that has flowed back can be easily discharged out of the machine due to a pressure difference, which can greatly contribute to improving the performance of the present apparatus (claim 1).

Further, since at least one of the width and the depth of the peripheral groove is configured to gradually increase from the upper part to the lower part of the outer peripheral surface of the inner nozzle, even if the cross-sectional area is the same, the molten metal is melted. In addition to being able to easily discharge the resin, it is possible to further increase the discharge amount of the molten resin by gradually increasing the width and depth (cross-sectional area) of the peripheral groove (claim 2).

Further, since the seal bush is provided at the end of the outer nozzle on the drive source side, in addition to the discharge of the molten resin by the circumferential groove, the leakage of the molten resin can be prevented by the seal bush, and the leakage of the resin can be prevented. This can significantly reduce the time required to hinder the operation of the inner nozzle and remove the solidified resin,
There is an advantage that the production efficiency can be improved (claim 3).

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view showing a main part of a sandwich molding nozzle according to an embodiment of the present invention, which is cut away.

FIG. 2 is a side view, partially broken away, showing a main part of the sandwich molding nozzle according to one embodiment of the present invention.

FIG. 3 is an enlarged perspective view showing a main part of the sandwich molding nozzle according to one embodiment of the present invention, with a part thereof broken away.

FIG. 4 is a partially sectional plan view showing a main part of a conventional sandwich molding nozzle.

[Explanation of symbols]

 1, 31 Outer nozzle 1a, 31a Injection port 1b, 33a Connecting portion 1c, 2c, 31c Drive source side end 2, 32 Inner nozzle 2a, 32a Discharge port 3, 33 Needle 4, 34 First resin injection hole 5, 35 Second resin injection hole 6, 7, 36, 37 Void portion 8, 9, 38, 39 Resin passage 10, 40 Resin communication hole 11, 13, 16, 51 Peripheral groove 12, 15, 52 Resin extraction hole 14 Communication Hole 32b Flange part 41 Sealing bush 53 Seal bush

Claims (3)

[Claims] A first resin for injecting a first resin into a tip.
A hollow outer nozzle having an injection port, and a second injection port for injecting a second resin at the tip so as to be aligned with the first injection port, and driven by a first drive source. And a hollow inner nozzle slidably fitted in the inner diameter surface of the outer nozzle, and slidably fitted in the inner diameter surface of the inner nozzle by being driven by the second drive source. The first resin is injected through a first resin injection hole that penetrates a side wall of the outer nozzle, and the second resin is injected into the outer nozzle and the inner nozzle. In a sandwich molding nozzle for injecting via a second resin injection hole penetrating each side wall, between a formation position of the second resin injection hole in the inner nozzle and a drive source side end portion In the outer peripheral surface of the inner nozzle, a helical circumferential groove extending from an upper position close to the second resin injection hole to a lower position close to the drive source side end is formed. A nozzle for sandwich molding, characterized in that a lower resin vent hole communicating with the peripheral groove and opening to the outside is provided at a lower portion of the outer nozzle. 2. The method according to claim 1, wherein at least one of the width and the depth of the circumferential groove is configured to gradually increase from an upper portion to a lower portion of the outer peripheral surface of the inner nozzle. The sandwich molding nozzle according to the above. 3. A seal bush that slidably supports the inner nozzle is provided at an end of the outer nozzle on a drive source side, and a position where the seal bush is disposed and a position where the second resin injection hole is formed. The sandwich forming nozzle according to claim 1 or 2, wherein the circumferential groove is provided between the nozzle and the nozzle.