JP3545518B2 - Fluid injection and recovery device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hollow injection molding apparatus for molding a hollow mold by injecting a molten resin into a mold cavity and injecting a fluid such as a pressurized gas. The present invention relates to a fluid injection / collection device used for discharging / collecting a fluid from a fluid.
[0002]
[Prior art]
A predetermined amount of molten resin is injected with a pressurized fluid, for example, a gas such as nitrogen gas, carbon dioxide gas, or air, or a liquid such as water, alcohol, liquid paraffin, or an oligomer (hereinafter, collectively referred to as “fluid”). Hollow injection molding, in which a hollow mold is molded by injecting into a cavity of a mold later or simultaneously with injection of a molten resin, has already been put into practical use.
[0003]
In the above-mentioned hollow injection molding, a method of injecting a fluid into a cavity is roughly classified into the following two methods.
[0004]
(1) A method of injecting a fluid from an injection nozzle of an injection molding machine that injects a molten resin, wherein a fluid is injected from a fluid nozzle built in a slightly rear end side of the injection nozzle (hereinafter, referred to as a “nozzle method”).
[0005]
(2) A method in which an opening is formed in a mold at a desired position in a cavity, and a fluid is injected from a needle inserted therein (hereinafter, referred to as a “needle method”).
[0006]
The nozzle system has been proposed in Japanese Patent Publication No. 57-14968, Japanese Patent Publication No. 61-59899, Japanese Patent Application Laid-Open No. 2-289327, and the like.
[0007]
On the other hand, there are two types of needle systems: a system in which a needle is inserted into an opening formed in a cavity and fixed, and a system in which a needle can be advanced and retracted without fixing the needle. The former is described, for example, in JP-A-2-289327, and the latter is described, for example, in JP-A-14014012.
[0008]
[Problems to be solved by the invention]
In the case of the above-mentioned nozzle system, since the fluid nozzle is built in the injection nozzle, there is a problem that the position of the fluid nozzle with respect to the cavity of the mold is limited, and the injection position of the fluid is limited. In addition, there is also a problem that the molten resin easily enters at the time of injection to block the fluid nozzle.
[0009]
In the above-mentioned needle method, a needle is arranged corresponding to a position where a hollow part such as a thick part or a rib structure part of a molded product is desired to be formed and a fluid is injected, so that the hollow part is surely formed at the position. There is a merit that can be formed.
[0010]
However, in the needle method fixed to the mold, the fluid is collected through the same needle hole as the fluid injection, so that the needle clogging due to the backflow of the molten resin during the fluid collection cannot be completely prevented. There is. In addition, when the diameter of the hole of the needle is increased, the backflow of the molten resin is more likely to occur. Therefore, the hole of the needle is forced to be a pore, and there is a problem that it takes time to collect the fluid through the pore.
[0011]
Further, in the needle system capable of moving back and forth with respect to the mold, the needle is advanced by a driving source, and a fluid is injected in a state where the tip is in close contact with a valve seat of the mold, and the needle is retracted. Thus, the space between the tip and the valve seat of the mold is opened, and the fluid is discharged from the space around the needle to the outside air.
[0012]
However, in this method, since the fluid is directly discharged to the atmosphere and cannot be collected, there is a problem that the fluid is disposable and wasteful, and the working environment is deteriorated depending on the type of the fluid. In addition, since the fluid in the hollow object is released to the atmosphere at once by the retreat of the needle, considerable noise is generated when the fluid escapes, and the inner wall of the hollow portion of the hollow object is disturbed by the discharge of the fluid. In addition, there is a problem that the mold reproducibility of the hollow mold, that is, the quality of the product surface is easily deteriorated due to the impaired product surface.
[0013]
The present invention has been made in view of such a conventional problem, and a first object of the present invention is to allow a fluid to be injected into a desired position in a mold cavity, and to block an injection path due to a backflow of a molten resin. An object of the present invention is to provide a fluid injecting / collecting device capable of promptly collecting a fluid without generating a fluid. Further, a second object of the present invention is to provide a fluid injection / recovery device capable of recovering a fluid without impairing the reproducibility of a hollow mold.
[0014]
[Means for Solving the Problems]
In order to achieve the first object, according to the first aspect of the present invention, a sleeve which is inserted into an opening portion formed in a mold and has a collection port at a tip thereof,
A recovery path is inserted between the inner surface of the sleeve and the sleeve so as to be able to advance and retreat, and the forward end fits into the recovery opening of the sleeve during forward movement, and the distal end faces the inside of the mold from the recovery opening. A needle that opens the mouth to connect the recovery path to the mold and connects the recovery path to the fluid recovery pipe;
A needle pin that is inserted into the needle and has a narrow injection path that is open at the tip of the needle and that is connected to the fluid supply pipe at least when the needle is advanced, between the needle inner peripheral surface and the needle. This is a fluid injection / recovery device.
[0016]
According to a second aspect of the present invention, there is provided a fluid injection / recovery device according to the first aspect of the present invention, wherein the fluid recovery pipe has a flow rate controller. It is.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0018]
FIG. 1 is a cross-sectional view of the fluid injection / recovery device with the needle 1 advanced, and FIG. 2 is a cross-sectional view of the fluid injection / recovery device with the needle 1 retracted.
[0019]
In the figure, 2 is a mold, 3 is a cavity, and 4 is an opening formed in the mold 2.
[0020]
A tubular sleeve 5 is inserted and fixed in the opening 4. The distal end (the mold 2 side) of the sleeve 5 is a collection port 6 having a slightly reduced diameter. A block 7 and a casing 8 that constitute an air cylinder are attached to the rear end side of the sleeve 5. The sleeve 5, the block 7, and the casing 8 are fixed to each other by bolts 9.
[0021]
A fluid supply pipe 10 for supplying a fluid and a fluid recovery pipe 11 for recovering the fluid are connected to the rear of the sleeve 5 so as to communicate with the inside of the sleeve 5, respectively. A flow controller (not shown) is attached to the supply interval 10 and the recovery pipe 11, respectively.
[0022]
A piston rod 12 is provided in an air cylinder constituted by the block 7 and the casing 8. The piston rod 12 moves forward in the air cylinder when air is supplied from the air supply pipe 13, and moves backward in the air cylinder when air is supplied from the air supply pipe 14. Further, the piston rod 12 advances and retreats along the rotation preventing pin 15 implanted in the block 7, and rotation around the axis is prevented. In addition, 16 and 17 are O-rings for preventing air leakage, and 18 and 19 are bearings for smoothly moving the piston rod 12 forward and backward.
[0023]
The needle 1 is inserted into the sleeve 5 so as to be able to advance and retreat in the axial direction. A needle pin 20 is inserted into a hole penetrating the needle 1 in the axial direction. The distal end of the needle 1 has a reduced diameter. When the needle 1 advances, it is fitted into the collecting port 6 of the sleeve 5 so that the distal end faces the cavity 3 as shown in FIG. As shown in FIG. 2, the collection port 6 of the sleeve 5 is opened.
[0024]
The front end of the piston rod 12 is connected to the rear end of the needle 1. This connection state will be described with reference to FIG.
[0025]
As shown in FIG. 3, the distal end of the piston rod 12 is a connecting portion 21 having a diameter slightly smaller than the inner diameter of the sleeve 5 (see FIGS. 1 and 2). Are scraped off to form the plate-like portion 22.
[0026]
On the other hand, the rear end of the needle 1 is also a connecting portion 23 having a diameter slightly smaller than the inner diameter of the sleeve 5 (see FIGS. 1 and 2). A notch 24 into which the plate-like portion 22 can be fitted is formed. At the rear end of the needle pin 20, a hook 25 that can be fitted into the notch 24 is also provided.
[0027]
The needle 1 and the piston rod 12 are connected by fitting the plate-like portion 22 of the piston rod 12 into the notch 24 of the needle 1 with the hook 25 of the needle pin 20 fitted in the notch 24 of the needle 1. It is connected by inserting and fixing the pin 26.
[0028]
Since the needle 1 in which the needle pin 20 is inserted and the piston rod 12 are connected as described above, the needle 1 and the needle pin 20 are integrally formed with the sleeve 5 as the piston rod 12 advances and retreats. 1 and FIG. 2). Further, since the rotation of the piston rod 12 around the axis is prevented by the rotation preventing pin 15, the rotation of the needle 1 and the needle pin 20 connected as described above around the axis is also prevented. is there.
[0029]
As shown in FIG. 4, the outer peripheral portion of the needle pin 20 is partially cut in the axial direction, and a narrow slit-shaped injection passage opening at the tip of the needle 1 is provided between the needle pin 20 and the inner peripheral surface of the needle 1. 27 are formed. As shown in FIGS. 1 and 2, the injection path 27 extends to the connection portion 23 at the rear end of the needle 1. The connecting portion 23 at the rear end of the needle 1 and the connecting portion 21 at the distal end of the piston rod are slightly smaller in diameter than the inner diameter of the sleeve 5 as described above. 28 are formed. The gap 28 is connected to the fluid supply pipe 10 and is connected to the injection path 27 by a connection hole 29 formed vertically from the outer peripheral surface of the needle 1 toward the center.
[0030]
As also shown in FIG. 4, a plurality of grooves are cut in the outer peripheral surface of the needle 1 in the axial direction, so that a wide recovery path is formed between the outer peripheral surface of the needle 1 and the inner peripheral surface of the sleeve 5. 30 are formed. As shown in FIGS. 1 and 2, the recovery path 30 extends slightly to the rear of the needle 1 and is disconnected from the fluid recovery pipe 11 when the needle 1 advances. Sometimes it is connected to the fluid recovery pipe 11.
[0031]
Reference numerals 31 and 32 denote O-rings for preventing leakage of the fluid injected into the cavity 3.
[0032]
Next, a method of use and operation of the fluid injection / recovery device according to the first aspect of the present invention will be described with reference to FIGS.
[0033]
First, where the hollow portion is to be provided in the product, for example, a desired portion such as a thick portion or a rib structure portion for imparting strength is determined, and an opening 4 is formed in the wall of the mold 1 corresponding to the portion. And a sleeve 5 is inserted through the opening 4 and fixed.
[0034]
The fluid injection / recovery device is attached to the mold 2 as described above, and air is supplied from the air supply pipe 13 to advance the piston rod 12 to the limit as the predetermined molten resin is injected. As a result, the needle 1 advances together with the needle pin 20 in the sleeve 5, and as shown in FIG. 1, the tip of the needle 1 fits into the collection port 6 of the sleeve 5, and the tip of the needle 1 is It is exposed in the cavity 3. At this time, the narrow injection path 27 formed between the needle 1 and the needle pin 20 is connected to the fluid supply pipe 10 via the connection hole 29 and the gap 28. Therefore, when the fluid is supplied from the fluid supply pipe 10, the fluid is injected into the cavity 3 through the injection path 27.
[0035]
On the other hand, when molding is completed by supplying a predetermined amount of fluid at a predetermined pressure, air is supplied from the air supply pipe 14 to retract the piston rod 12 to the limit. As a result, the needle 1 retreats inside the sleeve 5 integrally with the needle pin 20, and as shown in FIG. 2, the tip end of the needle 1 retracts into the sleeve 5 to open the collection port 6 of the sleeve 5, The collection path 30 communicates with the cavity 3 via the collection port 6. At this time, since the recovery path 30 is connected to the fluid recovery pipe 11, while controlling the flow rate by a flow controller (not shown) of the fluid recovery pipe 11, the fluid is recovered in, for example, a recovery tank or the like, and then re-collected. Can be used.
[0036]
In the fluid injection / recovery device described with reference to FIGS. 1 to 4, the injection path 27 is connected to the fluid supply pipe 10 regardless of whether the needle 1 moves forward or backward. This connection may be cut off only when the needle 1 is retracted.
[0037]
Next, a reference example of the present invention will be described with reference to FIGS.
[0038]
Basically, it is the same as the fluid injection / recovery device according to the first aspect of the present invention described with reference to FIGS. The difference is the following three points.
[0039]
The first point is that the injection path 27 is formed by a fine hole formed in the central axis direction of the needle 1 without the needle pin 20. The second point is that the recovery path 30 is formed by making the diameter from the tip to the middle of the needle 1 considerably smaller than the inner diameter of the sleeve 5 instead of providing a groove on the outer circumference of the needle 1. The third point is that the needle 1 and the piston rod 12 are integrated (however, the connection as shown in FIG. 3 can also be performed).
[0040]
Except for the above points, it is the same as the fluid injection / recovery device according to the invention of claim 1 described in FIGS. 1 to 4, and the same reference numerals in FIGS. 5 and 6 as those in FIGS. 1 to 4 indicate the same members. Things.
[0041]
The advantage of the fluid injection / recovery device according to this reference example is that the structure is simpler than the fluid injection / recovery device according to the first aspect of the present invention. However, it is difficult to form a small-diameter fine hole serving as the injection path 27 in the center portion of the needle 1, and in this respect, there is no need for such a trouble of forming such a fine hole. Excellent fluid injection and recovery equipment.
[0042]
Next, the operation of the fluid injection / recovery device according to the above reference example will be described mainly with respect to differences from the fluid injection / discharge device according to the first aspect of the present invention.
[0043]
FIG. 5 shows a state in which air is supplied from the air supply pipe 13 and the piston rod 12 (needle 1) is advanced to the limit. In this state, the gap 28, the connection hole 29, and the injection path 27 are removed from the fluid supply pipe 10. Fluid can be injected through.
[0044]
When air is supplied from the air supply pipe 14 and the piston rod 12 (needle 1) is retracted to the limit, the tip of the piston rod 12 is retracted into the sleeve 5 and becomes clear, as apparent from the description of FIG. And the fluid recovery pipe 11 is connected to the recovery path 30, so that the fluid can be recovered while adjusting the flow rate by the flow controller (not shown) of the fluid recovery pipe 11. .
[0045]
Even in the case of the fluid injection / recovery device according to the first aspect of the present invention described above, even in the case of the fluid flow control device according to the reference example , when the fluid is not injected by these or when the injection position is changed, The sleeve 5 may be removed and the opening 4 may be backfilled with the same material as the mold 2. Further, although the air cylinder is used as the driving source, a hydraulic cylinder and other devices can be used as the driving source.
[0046]
【The invention's effect】
The present invention is as described above, and has the following effects.
[0047]
(1) Since the fluid injection / recovery device according to the present invention is a needle type device, the mounting position can be freely selected, and the hollow portion can be reliably formed at a desired position of the product. .
[0048]
(2) The injection of the fluid is performed via the injection path 27, and the recovery of the fluid is performed via the recovery path 30 different from the injection path 27. Therefore, there is no fear that the injection path 27 is clogged by the backflow of the molten resin. . Further, since the injection path 27 is narrow, the molten resin is less likely to enter, so that the injection path 27 is less likely to be clogged by the backflow of the resin.
[0049]
(3) Since the recovery path 30 is wide, the recovery of the fluid can be performed speedily. In addition, the fluid can be collected in a collection tank or the like via the fluid collection pipe 11, and the cost can be reduced by reuse while preventing waste and deterioration of the working environment due to being released to the atmosphere.
[0050]
(4) If a flow rate regulator is provided in the fluid recovery pipe 11, the flow rate at the time of fluid recovery can be adjusted and the burst of the fluid can be prevented from being blown out. The drop can be prevented.
[0051]
(5) The operation of each part can be easily controlled by a computer, and the productivity can be easily improved by automation.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of the fluid injection / recovery device according to the first aspect of the present invention in a state where a needle is advanced.
FIG. 2 is a sectional view of the fluid injection / recovery device shown in FIG. 1 in a state where a needle is retracted.
FIG. 3 is an exploded perspective view of a connecting portion between a needle and a piston rod of the fluid injection / recovery device shown in FIG.
FIG. 4 is a sectional view taken along line AA in FIG.
FIG. 5 is a cross-sectional view of the fluid press-in / collection device according to the reference example in a state where a needle is advanced.
FIG. 6 is a sectional view taken along line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Needle 2 Die 3 Cavity 4 Opening 5 Sleeve 6 Collection port 7 Block 8 Casing 9 Bolt 10 Fluid supply pipe 11 Fluid collection pipe 12 Piston rod 13 Air supply pipe 14 Air supply pipe 15 Rotation prevention pin 16 O-ring 17 O Ring 18 Bearing 19 Bearing 20 Needle pin 21 Connection part 22 Plate part 23 Connection part 24 Notch part 25 Hook 26 Connection pin 27 Injection path 28 Gap part 29 Connection hole 30 Recovery path 31 O-ring 32 O-ring

Claims (2)

The sleeve is inserted into an opening formed in the mold, has a collection path at the tip, and has a collection path between the inner surface of the sleeve and is inserted into the sleeve so as to be able to advance and retreat. A needle that fits into the collecting port of the sleeve so that the tip faces the inside of the mold from the collecting port, and opens the collecting port when retracted to connect the collecting path to the mold and connect the collecting path to the fluid collecting pipe. A needle pin inserted between the needle and the inner peripheral surface of the needle, the needle pin having a narrow injection path opened at the tip of the needle and connected to the fluid supply pipe at least when the needle is advanced. Fluid injection and recovery device. The fluid injection / recovery device according to claim 1 , wherein the fluid recovery pipe has a flow controller.

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