JP3806785B2 - Nozzle for sandwich molding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sandwich molding nozzle that is suitable for use in sandwich injection molding in which a cross section of a molded product is composed of a core layer and a skin layer in plastic molding.
[0002]
[Prior 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 molding nozzle disclosed in this publication will be described.
[0003]
FIG. 4 is a plan sectional view showing a part of a conventional side-switch molding nozzle in a sandwich injection molding machine with a part thereof broken. 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 the tip, 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.
[0004]
Reference numeral 2 denotes an inner nozzle, and this inner nozzle 2 is slidably fitted within the inner diameter surface of the outer nozzle 1 by being driven by a drive source (drive 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 the tip is for injecting the second resin so that it can be aligned with the first injection port 1a. A second injection port (discharge port) 2a is provided. FIG. 4 shows a state in which the inner nozzle 2 slides leftward and its tip abuts against the inner surface of the tip of the outer nozzle 1. In the figure, reference numeral 2 c denotes a drive source side end of the inner nozzle 2.
[0005]
Further, a gap 6 is formed between the inner diameter surface of the outer nozzle 1 and the outer diameter surface in the vicinity of the tip of the inner nozzle 2, and the gap 6 and the first resin injection hole 4 are made of resin. The passage 8 communicates.
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 gap portion 6 through the resin passage 8, and the first resin It is injected through the injection port 1a. In this case, the inner nozzle 2 shown in FIG. 4 is moved rightward.
[0006]
Further, in the figure, reference numeral 11 denotes a circumferential groove provided on the inner diameter surface of the outer nozzle 1, and this circumferential groove 11 communicates with a resin draining hole 12 provided in the outer nozzle 1 and opening downward from the outside. It is arranged at right angles to the axis of the inner nozzle 2. Then, the first resin leaking from the sliding gap between the outer nozzle 1 and the inner nozzle 2 is discharged by the circumferential groove 11 and the resin drain hole 12.
[0007]
Further, the circumferential groove 11 and the resin drain hole 12 are formed at the position where the first resin injection hole 4 and the second resin injection hole 5 are formed and the drive source side end 1c (hereinafter simply referred to as the end 1c) of the outer nozzle 1. It is provided in between. In the figure, reference numeral 1b denotes a connecting portion with the machine casing.
In the figure, reference numeral 13 denotes a circumferential groove provided on the inner diameter surface of the inner nozzle 2, and this circumferential groove 13 is provided in the outer nozzle 1 through a communication hole 14 provided in the diameter direction of the inner nozzle 2. It communicates with the resin drain hole 15 that opens to the outside lower side, and this circumferential groove 13 is also arranged at right angles to the axis of the inner nozzle 2. Then, the second resin leaking from the sliding gap between the inner nozzle 2 and the needle 3 is discharged by the circumferential groove 13 and the communication hole 14.
[0008]
Further, the circumferential groove 13, the communication hole 14, and the resin drain hole 15 are formed at the positions where the first resin injection hole 4 and the second resin injection hole 5 are formed in the same manner as the circumferential groove 11 and the resin drain hole 12 described above. And the drive source side end 1c of the outer nozzle 1. Reference numeral 16 denotes an auxiliary circumferential groove provided on the inner diameter surface of the outer nozzle 1. Reference numeral 3 denotes a needle which is slidably inserted into the inner diameter surface of the inner nozzle 2 by being driven by a driving source. A gap 7 is formed between the inner diameter surface of the nozzle 2. The gap 7 and the second resin injection hole 5 are communicated with the resin passage 9 via the 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 leftward and its tip abuts against the inner surface of the tip of the inner nozzle 2.
[0009]
With such a configuration, in the sandwich molding nozzle shown in FIG. 4, the molten resin (first resin and second resin) has respective injection holes (first resin injection hole 4 and second resin injection hole 5). In the first resin, most of the first resin flows toward the first injection port 1a, but a part of the first resin flows from the sliding gap between the outer nozzle 1 and the inner nozzle 2 to the end of the outer nozzle 1. It leaks in the direction of the part 1c. At this time, the leaked resin is stored in a circumferential groove 11 formed on the inner diameter surface of the outer nozzle 1.
[0010]
Further, most of the second resin flows toward the second injection port 2a, but a part of the second resin is directed from the sliding gap between the inner nozzle 2 and the needle 3 toward the end 2c of the inner nozzle 2. Leak. In this case as well, it is stored in the circumferential groove 13 formed on the inner diameter surface of the inner nozzle 2.
Thereafter, the first resin accumulated in the circumferential groove 11 flows down through the resin draining hole 12 communicating with the circumferential groove 11 and is discharged, and the second resin accumulated in the circumferential groove 13 is The resin flows down from the resin drainage hole 15 through the communication hole 14 communicating with the circumferential groove 13 and is discharged.
[0011]
In other words, the resin discharged downward from the resin removal holes 12 and 15 can be dropped and directly recovered, and even when solidified, it hangs down in the form of a rod or a belt, so that the hanged resin is broken off. Thus, the leaked resin can be removed.
[0012]
[Problems to be solved by the invention]
However, in such a conventional sandwich molding nozzle, the resin leaks from the peripheral groove 11 provided in the inner diameter surface of the outer nozzle 1 and the resin outlet hole that opens downward from the outside of the drive source side end 1c. Although the circumferential groove 11 is disposed at right angles to the axis of the inner nozzle 2, the resin accumulated in the circumferential groove 11 is pushed out toward the resin drain hole 12. There is a problem that the pressing force is insufficient, and the resin cannot be sufficiently removed on the side away from the resin removal hole 12 in the circumferential groove 11 (the upper side of the inner nozzle 2).
[0013]
The present invention has been devised in view of such problems, and by elaborating the arrangement of the circumferential grooves provided on the outer peripheral surface of the inner nozzle, the leaked molten resin can be easily discharged. An object of the present invention is to provide a sandwich molding nozzle.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a sandwich molding nozzle of the present invention includes a hollow outer nozzle having a first injection port for injecting a first resin at a tip, and the first injection port at a tip. And a second injection port for injecting the second resin so that it can be aligned with the nozzle, and is slidably fitted into the inner diameter surface of the outer nozzle by being driven by the first drive source. A hollow inner nozzle and a needle that is slidably inserted into the inner diameter surface of the inner nozzle by being driven by a second driving source, and the first resin is disposed on the side wall of the outer nozzle. Sandwich composition in which the second resin is injected through the first resin injection hole penetrating and the second resin is injected through the second resin injection hole penetrating the side walls of the outer nozzle and the inner nozzle. In the nozzle for driving, between the position where the second resin injection hole is formed in the inner nozzle and the driving source side end, the outer peripheral surface of the inner nozzle is driven from the position above the second resin injection hole. A spiral wound circumferential groove extending to the lower position near the source side end is formed, and a downward resin drain hole that opens to the outside is communicated with the circumferential groove at the lower portion of the outer nozzle. Is provided (claim 1).
[0015]
In this case, at least one of the width and the depth of the circumferential groove can be configured to gradually increase from the upper part to the lower part of the outer peripheral surface of the inner nozzle (claim 2).
In addition, a seal bush that slidably supports the inner nozzle is provided at the end of the outer nozzle on the drive source side. Between the position where the seal bush is disposed and the position where the second resin injection hole is formed, A groove can be provided (claim 3).
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1 to 3 show the structure of a sandwich molding nozzle according to an embodiment of the present invention. FIG. 1 is a cross-sectional plan view showing a principal part thereof broken away, and FIG. 2 is a partly broken part thereof. FIG. 3 is an enlarged perspective view showing a part of the essential part thereof.
[0017]
As shown in FIG. 1, the sandwich molding nozzle according to the present embodiment includes a hollow outer nozzle 31, a hollow inner nozzle 32 fitted in the inner peripheral surface of the outer nozzle 31, and the inner A needle 33 fitted in the inner peripheral surface of the nozzle 32 is provided. Hereinafter, the configuration of each part will be described in detail.
[0018]
Specifically, the outer nozzle 31, one having a first exit opening (discharge port) 31a for ejecting the trees fat to the tip, the first resin, a first passing through the side wall of the outer nozzle 31 The resin is injected through the resin injection hole 34.
Further, a gap portion 36 through which the first resin flows is formed between the inner peripheral surface of the outer nozzle 31 and the outer peripheral surface in the vicinity of the tip of the inner nozzle 32. The gap portion 36 and the first resin The injection hole 34 is communicated with the resin passage 38.
[0019]
When the first resin is injected into the mold (not shown, the same applies hereinafter), the inner nozzle 32 slides to the right, and the gap 36 and the first injection port 31a communicate with each other. The first resin flows along the resin passage 38 to the entire circumference of the gap portion 36 and is injected into the mold through the first injection port 31a.
The inner nozzle 32 has a second injection port 32a for injecting the second resin so that the inner nozzle 32 can be aligned with the first injection port 31a at the tip, and a first drive source (not shown). ) Is slidably fitted into the inner peripheral surface of the outer nozzle 31. The second resin is injected through the second resin injection holes 35 penetrating the side walls of the outer nozzle 31 and the inner nozzle 32.
[0020]
Further, the needle 33 is slidably fitted into the inner peripheral surface of the inner nozzle 32 by being driven by a second drive source (not shown). A gap 37 that circulates the second resin is formed between the inner nozzle 32 and the inner peripheral surface of the inner nozzle 32. The gap portion 37 and the second resin injection hole 35 provided on the side wall of the outer nozzle 31 are communicated with each other by a resin passage 39 and a communication hole 40.
[0021]
Specifically, as shown in FIG. 3, the resin passage 39 is provided over a half circumference of the inner nozzle 32 in the circumferential direction , and includes two communication holes (long holes) provided perpendicular to the diameter direction. ) 40 allows the gap 37 and the second resin injection hole 35 to communicate with each other.
When the second resin is injected into the mold, as shown in FIG. 1, the inner nozzle 32 slides in the left direction to connect the gap 36 and the first injection port 31a. The second resin is closed and flows into the gap 37 through the resin passage 39 and the communication hole 40 from the second resin injection hole 35 described above, via the second injection port 32a and the first injection port 31a. It is designed to be injected into the mold .
[0022]
Further, between the position where the second resin injection hole 35 is formed in the inner nozzle 32 and the driving source side end, the position of the upper part of the inner nozzle 32 that is close to the second resin injection hole 35 is provided. A spiral wound circumferential groove (square groove) 51 is formed extending from the upper end to the lower position near the drive source side end (divided from the upper point to the left and right and toward the lower point), The circumferential groove 51 can prevent resin leaking from the drive source side of the inner nozzle 32 and the outer nozzle 31 .
[0023]
Specifically, this circumferential groove 51 is provided between the position where the second resin injection hole 35 is formed and the position where the seal bush 53 provided on the drive source side end 31c is disposed, as will be described later. It has been.
As shown in FIGS. 2 and 3, the width (see b in FIG. 3) and depth (see d in FIG. 3) of the circumferential groove 51 are the upper parts (see FIGS. 2 and 3) of the inner nozzle 32. As shown in FIG. 2A and FIG. 3B, the cross-sectional area increases gradually from the top to the bottom. Specifically, as shown in FIGS. 2 and 3, the circumferential groove 51 is formed in a left and right-handed spiral shape that is close to the drive source side by a length L.
[0024]
Here, the cross-sectional shape of the circumferential groove 51 is a square groove, but the cross-sectional shape is not limited to this, and other shapes are possible. As for the gradual increase of the width and depth of the circumferential groove 51, at least one of the width and depth of the circumferential groove 51 may be gradually increased from the upper part to the lower part of the outer peripheral surface of the inner nozzle 32. The rate of gradual increase is not limited to this, and can be changed according to the characteristics of the resin or the outer diameter of the inner nozzle 32.
[0025]
Further, at the lower part of the outer nozzle 31, there is provided a downward resin drain hole 52 that communicates with the circumferential groove 51 (communication in FIG. 2B) and opens to the outside. The resin accumulated in is drained.
Thus, since the circumferential groove 51, rather than being disposed at right angles to the inner nozzle 3 2 axes, it is arranged inclined helical line shape from the top over the bottom, i.e., the inner nozzle 3 short flow distance in the second top (see FIG. 2) that are arranged to be longer than the lower, the resin pressure of the molten resin entering the circumferential groove 51 becomes higher in the upper, thus The molten resin is pushed in the circumferential direction of the inner nozzle 32 and can be easily discharged to the outside from the lower resin drain hole 52.
[0026]
Incidentally, a seal bush 53 that slidably supports 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 flanged metal packing (bush-shaped metal packing with a flange) attached by a plurality of bolts 54. .
[0027]
Further, the fitting gap between the seal bush 53 and the inner nozzle 32 is made smaller than the fitting gap at the center portion (between the resin passage 38 and the circumferential groove 51) between the outer nozzle 31 and the inner nozzle 32. In this way, by making the fitting gap between the two sufficiently smaller than the fitting gap between the general sliding portions of the outer nozzle 31 and the inner nozzle 32, a large flow resistance is given to the molten resin. Therefore, it is possible to prevent molten resin that flows back in the axial direction (molten resin that passes through the circumferential groove 51 and enters the sliding gap on the drive source side again).
[0028]
Further, in FIG. 1, reference numeral 32b is a flange portion of the inner nozzle 32, and this flange portion 32b is provided at the drive source side end portion of the inner nozzle 32, and is a first hydraulic cylinder (illustrated) as a first drive source. Is omitted).
Further, reference numeral 33a is a connecting portion, and this connecting portion 33a is provided on the drive source side of the needle 33, and is a second hydraulic cylinder (not shown) as a second drive source different from the flange portion 32b described above. 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 drive source side of the needle 33 is slidably inserted by a sealing bush 41 fitted to the inner nozzle 32, The fitting gap is reduced to maintain the airtightness. 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.
[0029]
Thus, 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 molten resin that flows back in the axial direction of the needle 33. is there.
With the above-described configuration, when the first resin (molten resin) is injected, the sandwich molding nozzle is driven at the tip of the needle 33 by driving the second drive source in FIG. By closing the communication between the injection port 32a and the gap portion 37 and driving the first drive source and the second drive source, the inner nozzle 32 and the needle 33 are moved backward to the drive source side, and the gap portion 36 and the first drive source are driven . by communicating the injection port 31a, a first resin which is note input from the first resin injection hole 34 is injected into the mold from a first injection port 31a.
[0030]
Thereafter, when the second resin (molten resin) is injected, by driving the first drive source, first, the inner nozzle 32 is advanced as shown in FIG. The communication between the first injection port 31a and the gap 36 in the first resin injected from the hole 34 is closed. In this state, by driving the second drive source, communicating causes and the void portion 37 second injection port 32a to retract the needle 33.
[0031]
When the second resin is note input from the second resin injection hole 35, increases the pressure of the resin within the resin passage 39, the inner nozzle 32 as a result, the second resin is communicating through the communication holes 40 Is injected into the mold through the second injection port 32a and the first injection port 31a through a gap 37 formed between the inner peripheral surface of the needle 33 and the outer peripheral surface of the needle 33.
[0032]
At this time, the second resin injected from the second resin injection hole 35, the majority flows toward the second injection port 32a through a small resin passage 39 flow resistance, in part, mold Some of the molten resin pressurized to the inside and the gap portion 37 flows backward from the portion of the resin passage 39 having a small flow resistance toward the drive source side (the seal bush 53 side) of the outer peripheral portion of the inner nozzle 32. The reversely flowing molten resin enters the circumferential groove 51 provided on the drive source side with respect to the second resin injection hole 35, drops pressure, and accumulates in the circumferential groove 51.
[0033]
Thereafter, the molten resin collected in the circumferential groove 51 is pushed downward in the circumferential direction where the flow resistance of the circumferential groove 51 is small, and is discharged to the outside from the resin drain hole 52 below the outer nozzle 31 . That is, since the circumferential groove 51 is inclined in a winding shape (because the flow distance is short in the upper part and is short in the lower part), the upper resin pressure becomes higher, and it is easy to enter the lower resin drain hole 52. Flows out.
[0034]
In addition, the second resin injected from the second resin injection hole 35 attempts to flow back around the outer periphery of the needle 33, but is inserted from the drive source side to the position of the second resin injection hole 35. Since the flow resistance is increased by the sealing bush 41, it flows to the second injection port 32a without backflow.
As described above, according to the sandwich molding nozzle as one embodiment of the present invention, the peripheral groove 51 that facilitates flow in the circumferential direction of the inner nozzle 32 is provided in the shape of a spiral winding, and the resin draining that communicates with the circumferential groove 51 is provided. Since the holes 52 are provided, the backflowed molten resin can be easily discharged out of the apparatus due to the pressure difference, which can greatly contribute to the performance improvement of the apparatus.
[0035]
In addition, since at least one of the width and depth of the circumferential 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, even if the cross-sectional area is the same, the molten resin In addition to being able to be easily discharged, the discharge amount of the molten resin can be further increased by gradually increasing the width and depth (cross-sectional area) of the circumferential groove 51.
[0036]
Further, since the seal bush 53 is provided at the drive source side end portion 31c of the outer nozzle 31, in addition to the discharge of the molten resin by the circumferential groove 51, the leak of the molten resin can be prevented by this seal bush 53. Since the hindrance of the operation of the inner nozzle 32 caused by leakage and the time required to remove the solidified resin can be greatly reduced, there is an advantage that the production efficiency can be improved.
[0037]
Further, since the sealing bush 41 is provided on the flange portion 32b of the inner nozzle 32, 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 or the solidified resin can be prevented. The time required for removal can be greatly reduced.
Note that the present invention is not limited to this embodiment, and can be applied to other plastic injection molding within a range not departing from the gist of the present invention, such as changing molding conditions. Expected to be effective.
[0038]
【The invention's effect】
As described above in detail, according to the sandwich molding nozzle of the present invention, it is provided with a peripheral groove that facilitates flow in the circumferential direction of the inner nozzle in a helical winding shape, and a resin drain hole that communicates with the peripheral groove. As a result, the backflowed molten resin can be easily discharged out of the apparatus due to the pressure difference, which can greatly contribute to the improvement of the performance of the present apparatus (claim 1).
[0039]
In addition, at least one of the width and depth of the circumferential groove is configured to gradually increase from the upper part to the lower part of the outer peripheral surface of the inner nozzle, so that the molten resin can be easily used even if the cross-sectional area is the same. In addition, 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 circumferential groove (claim 2).
[0040]
Further, since the seal bush is provided at the end of the outer nozzle on the drive source side, in addition to discharging the molten resin through the circumferential groove, leakage of the molten resin can be prevented by this seal bush, and the inner portion caused by the leakage of the resin can be prevented. There is an advantage that production efficiency can be improved because obstruction of the operation of the nozzle and time required for removing the solidified resin can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional plan view of a main part of a sandwich molding nozzle according to an embodiment of the present invention, broken away.
FIG. 2 is a side view showing a part of the main part of a sandwich molding nozzle according to an embodiment of the present invention.
FIG. 3 is an enlarged perspective view showing a part of the main part of the sandwich molding nozzle according to the embodiment of the present invention, with a part broken away.
FIG. 4 is a plan sectional view showing a main part of a conventional sandwich molding nozzle with a part thereof broken away.
[Explanation of symbols]
1, 31 Outer nozzles 1a, 31a Injection ports 1b, 33a Connection portions 1c, 2c, 31c Drive source side end portions 2, 32 Inner nozzles 2a, 32a Discharge ports 3, 33 Needles 4, 34 First resin injection holes 5, 35 Second resin injection hole 6, 7, 36, 37 Air gap part 8, 9, 38, 39 Resin passage 10, 40 Resin communication hole 11, 13, 16, 51 Circumferential groove 12, 15, 52 Resin drain hole 14 Communication Hole 32b Flange 41 Sealing bush 53 Seal bush

Claims (3)

A hollow outer nozzle having a first injection port for injecting a first resin at the tip;
It has a second injection port for injecting the second resin so that it can be aligned with the first injection port at the tip, and is driven by the first drive source so as to be within the inner diameter surface of the outer nozzle. A hollow inner nozzle slidably inserted in
A needle that is slidably inserted in the inner diameter surface of the inner nozzle by being driven by the second drive source;
Injecting the first resin through a first resin injection hole penetrating the side wall of the outer nozzle,
In a sandwich molding nozzle for injecting the second resin through a second resin injection hole penetrating each side wall of the outer nozzle and the inner nozzle,
Between the formation position of the second resin injection hole in the inner nozzle and the drive source side end, the drive source is positioned on the outer peripheral surface of the inner nozzle from the upper position close to the second resin injection hole. A spiral winding circumferential groove extending to the lower position near the side end is formed,
A sandwich molding nozzle, characterized in that a downward resin release hole communicating with the circumferential groove and opening to the outside is provided at a lower portion of the outer nozzle. 2. The sandwich molding according to claim 1, wherein at least one of the width and depth of the circumferential groove is configured to gradually increase from the upper part to the lower part of the outer peripheral surface of the inner nozzle. nozzle. A seal bush that slidably supports the inner nozzle is provided at the drive source side end of the outer nozzle,
3. The sandwich molding according to claim 1, wherein the circumferential groove is provided between a position where the seal bush is disposed and a position where the second resin injection hole is formed. nozzle.

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