JPH0976275A - Fluid injection / recovery device - Google Patents

Abstract

(57) Abstract: In a fluid injection / recovery device used for hollow injection molding, a fluid can be injected at a desired position, and moreover, the fluid is rapidly recovered without causing clogging of the injection path due to the reverse flow of the molten resin. A fluid injection / recovery device that can SOLUTION: A recovery passage 30 is bored in the outer peripheral surface of a needle 1 in the axial direction and has a needle 1 and a needle pin 20 forming an injection passage 27 in the axial direction, or has an injection passage 27 in the central portion in the axial direction. The needle 1 is provided so as to be able to move back and forth within a sleeve 5 inserted and fixed in an opening 4 formed in a mold 2.
At the time of forward movement, the needle 1 is fitted into the recovery port 6 at the tip of the sleeve 5 so as to face the injection path 27 cavity 3 having an open front end, and at the time of backward movement, the recovery port 6 is opened so that the cavity 3 communicates with the recovery path 30. I shall.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hollow injection molding apparatus for molding a hollow molded article by injecting a molten resin into a cavity of a mold and injecting a fluid such as a pressurized gas,
The present invention relates to a fluid injection / recovery device used for injecting the fluid into the cavity and discharging / recovering the fluid from the cavity.

[0002]

2. Description of the Related Art 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 oligomer (hereinafter collectively referred to as "fluid") is supplied in a predetermined amount. Hollow injection molding has been already put to practical use, in which a molten resin is injected into a cavity of a mold after completion of injection of the molten resin or in parallel with injection of the molten resin to mold a hollow molded article.

In the above hollow injection molding, there are roughly two types of methods of injecting a fluid into a cavity.

(1) A method of injecting a fluid from an injection nozzle of an injection molding machine for injecting a molten resin. A method of injecting a fluid from a fluid nozzle built in at a slightly rear end side of the injection nozzle (hereinafter referred to as "nozzle method"). That).

(2) A method in which a die is provided with an opening portion which opens at a desired position of the cavity, and a fluid is injected from a needle inserted therein (hereinafter referred to as "needle method").

Regarding the nozzle system, Japanese Patent Publication No. 57-14
It is proposed in Japanese Patent No. 968, Japanese Patent Publication No. 61-59899, Japanese Patent Laid-Open No. 2-289327.

On the other hand, there are two types of needle system: a system in which the needle is inserted through an opening formed in the cavity and fixed, and a system in which the needle can be moved forward and backward without being fixed. . The former is, for example, JP-A-2-289327.
JP-A-64-
No. 14012.

[0008]

In the case of the above-mentioned nozzle system, since the fluid nozzle is built in the injection nozzle, 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. is there. In addition, there is also a problem that the molten resin easily intrudes during injection and easily closes the fluid nozzle.

In the above-mentioned needle system, a needle is arranged at a position where it is desired to form a hollow portion such as a thick wall portion or a rib structure portion of a molded article, and a fluid is injected, so that the portion is surely secured. There is a merit that a hollow portion can be formed.

However, in the needle system fixed to the die, the fluid is collected through the same hole of the needle as the fluid is press-fitted, so that the needle clogging caused by the backward flow of the molten resin during the fluid collection is not completely completed. There are problems that cannot be prevented. In addition, since the backflow of the molten resin is more likely to occur when the hole diameter of the needle is increased, the hole of the needle has to be a fine hole, and there is also a problem that it takes time to collect the fluid performed through the fine hole.

Further, in the needle system capable of advancing and retracting with respect to the mold, the needle is advanced by a driving source, and the tip of the needle is brought into close contact with the valve seat portion of the mold to inject the fluid, Is retracted to open the space between the tip of the needle and the valve seat of the mold, and the fluid is discharged from the space around the needle to the outside air.

However, in this method, since the fluid is directly discharged to the atmosphere and cannot be recovered, the fluid is thrown away as waste, and there is a problem that the working environment is deteriorated depending on the type of fluid. Also, since the fluid inside the hollow mold is suddenly released to the atmosphere due to the retreat of the needle, considerable noise is generated when the fluid escapes, and the inner wall of the hollow part of the hollow mold is disturbed by the discharge of the fluid. However, there is also a problem that the mold reproducibility of the hollow mold, that is, the surface of the product is impaired and the quality is apt to deteriorate.

The present invention has been made in view of such conventional problems, and a first object of the present invention is to inject a fluid into a desired position of a mold cavity and also to cause a reverse flow of molten resin. It is an object of the present invention to provide a fluid injection / recovery device capable of recovering a fluid quickly without causing clogging of the injection path. A second object of the present invention is to provide a fluid injection / recovery device capable of recovering a fluid without impairing the mold reproducibility of the hollow mold.

[0014]

In order to achieve the first object, in the invention of claim 1, there is provided a sleeve having a recovery port at a tip end, which is inserted into an opening portion formed in a mold. , With a recovery path between the inner surface of the sleeve and the sleeve so that it can be moved back and forth in the sleeve, and the tip end fits into the recovery port of the sleeve when advancing and the tip is exposed from the recovery port into the mold, while retracting Between the needle that connects the recovery passage to the fluid recovery pipe and connects the recovery passage to the inside of the mold by opening the recovery port and the inner peripheral surface of the needle, the needle is opened at the tip of the needle and at least when the needle advances, The fluid injection / recovery device is characterized by having a narrow injection path connected to the supply pipe and a needle pin inserted into the needle.

Further, in order to achieve the first object, according to the second aspect of the present invention, a sleeve having a recovery port at the tip, which is inserted into an opening formed in the mold, and a sleeve inner surface are provided. It has a recovery path between the two and is inserted into the sleeve so that it can be moved back and forth.The tip of the tip fits into the recovery port of the sleeve when advancing so that the tip surface faces the inside of the mold from the recovery port, A small diameter injection path having a needle that opens and connects the recovery path to the mold and that connects the recovery path to the fluid recovery tube, and the hole of the needle is connected to the fluid supply tube at least when the needle is advanced. Fluid injection characterized by consisting of
It is used as a recovery device.

Further, in order to achieve the second object, the invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the fluid recovery pipe has a flow controller. It is used as a recovery device.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Based on FIGS.
An embodiment of the present invention will be described.

FIG. 1 is a sectional view of the fluid injection / recovery device with the needle 1 advanced, and FIG. 2 is a sectional view of the fluid injection / recovery device with the needle 1 retracted.

In the figure, 2 is a mold, 3 is a cavity,
Reference numeral 4 is an opening formed in the mold 2.

A cylindrical sleeve 5 is inserted into and fixed to the opening portion 4. The tip of this sleeve 5 (mold 2
The side) has a recovery port 6 with a slightly reduced diameter. Further, a block 7 and a casing 8 forming 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 bolts 9 to each other.
It is fixed in.

A fluid supply pipe 10 for supplying a fluid and a fluid recovery pipe 11 for recovering the fluid are connected to the rear side of the sleeve 5 in a state of communicating with the inside of the sleeve 5, respectively. A flow rate controller (not shown) is attached to each of the supply space 10 and the recovery pipe 11.

A piston rod 12 is provided in the air cylinder composed of 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. In addition, the piston rod 12 is a block 7
It advances and retreats along the rotation prevention pin 15 that is planted in, and rotation around the axis is prevented. In addition, 16 and 17 are O-rings for preventing air leakage, and 18 and 19 are piston rods 12.
This is a bearing to facilitate the forward and backward movement.

The needle 1 is inserted into the sleeve 5 so as to be movable back and forth in the axial direction. A needle pin 20 is inserted into a hole penetrating the needle 1 in the axial direction. Further, the tip of the needle 1 has a reduced diameter, and when the needle 1 is moved forward, as shown in FIG.
The recovery port 6 of the sleeve 5 is fitted into the recovery port 6 of the sleeve 5 so that its tip faces the inside of the cavity 3, and when the needle 1 is retracted, the recovery port 6 of the sleeve 5 is opened as shown in FIG.

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.

As shown in FIG. 3, the piston rod 1
The tip of 2 is a connecting portion 21 having a diameter slightly smaller than the inner diameter of the sleeve 5 (see FIGS. 1 and 2).
Both sides of the tip end of 1 are scraped off to form a plate-shaped portion 22.

On the other hand, the rear end of the needle 1 also has a sleeve 5
The connecting portion 23 having a diameter slightly smaller than the inner diameter (see FIGS. 1 and 2)
A cutout 24 into which the plate-shaped portion 22 of the piston rod 12 can be fitted is formed on the rear end side of the connecting portion 23. Also, the needle pin 20
At the rear end, there is provided a hook 25 which can also be fitted into the cutout 24.

For the needle 1 and the piston rod 12, the hook 25 of the needle pin 20 is attached to the cutout portion 2 of the needle 1.
4 is fitted to the plate-shaped portion 2 of the piston rod 12
2 is fitted into the notch portion 24 of the needle 1, and the connecting pin 26 is inserted and fixed, whereby the needle 1 is connected.

Needle 1 in which needle pin 20 is inserted
Since the piston rod 12 and the piston rod 12 are connected as described above, the needle 1 and the needle pin 20 integrally move forward and backward in the sleeve 5 (see FIGS. 1 and 2) as the piston rod 12 moves forward and backward. It is a thing. Since the rotation of the piston rod 12 about 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 about the axis is also prevented. is there.

As clearly shown in FIG. 4, the needle pin 2
The outer peripheral part of 0 is partially cut in the axial direction, and the needle 1
A narrow slit-shaped injection passage 27 that opens at the tip of the needle 1 is formed between the injection passage 27 and the inner peripheral surface of the needle 1. This injection channel 27
1 extends to the connecting portion 23 at the rear end of the needle 1, as shown in FIGS. The connecting portion 23 at the rear end portion of the needle 1 and the connecting portion 21 at the tip end portion of the piston rod
Has a diameter slightly smaller than the inner diameter of the sleeve 5 as described above, and a gap 28 is formed between the inner peripheral surface of the sleeve 5. In addition, the gap 28 is provided in the fluid supply pipe 10.
It is also connected to the injection passage 27 by a connection hole 29 that is vertically formed from the outer peripheral surface of the needle 1 toward the center.

As also clearly shown in FIG. 4, the outer peripheral surface of the needle 1 is axially cut with a plurality of grooves, whereby the outer peripheral surface of the needle 1 and the inner peripheral surface of the sleeve 5 are separated from each other. A wide recovery path 30 is formed. This recovery path 30
As shown in FIGS. 1 and 2, the needle 1 extends slightly rearward of the needle 1 and is disconnected from the fluid recovery pipe 11 when the needle 1 is advanced, but is disconnected when the needle 1 is retracted. 11 is connected.

Incidentally, 31 and 32 are O-rings for preventing the fluid injected into the cavity 3 from leaking.

Next, referring to FIG. 1 and FIG.
The usage method and operation of the fluid injection / recovery device according to the invention will be described.

First, a desired portion such as a thick wall portion or a rib structure portion for imparting strength is determined in which portion of the product the hollow portion is to be provided, and the wall of the mold 1 corresponding to that portion is opened. A hole 4 is bored, and a sleeve 5 is inserted through this hole 4 and fixed.

As described above, the present fluid injecting / recovering device is attached to the die 2, and air is supplied from the air supply pipe 13 to advance the piston rod 12 to the limit with the injection of a predetermined molten resin. As a result, the needle 1 is moved forward in the sleeve 5 together with the needle pin 20.
As shown in FIG. 3, the tip of the needle 1 is fitted into the recovery port 6 of the sleeve 5, and the tip of the needle 1 is exposed in the cavity 3. At this time, needle 1 and needle pin 2
The narrow injection passage 27 formed between 0 and 0 has a connecting hole 29.
And the fluid supply pipe 10 via 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 passage 27.

On the other hand, when a predetermined amount of fluid is supplied and the molding is completed, air is supplied from the air supply pipe 14 to retract the piston rod 12 to the limit. As a result, the needle 1 is integrated with the needle pin 20 and the sleeve 5
2, the tip of the needle 1 retracts into the sleeve 5 to open the recovery port 6 of the sleeve 5, and the recovery path 30 communicates with the cavity 3 through the recovery port 6, as shown in FIG. . At this time, since the recovery passage 30 is connected to the fluid recovery pipe 11, while the flow rate is adjusted by a flow rate controller (not shown) of the fluid recovery pipe 11, the fluid is recovered in a recovery tank, for example, and then recovered. Can be used.

In the fluid injection / recovery device described with reference to FIGS. 1 to 4, the injection passage 27 is connected to the fluid supply pipe 10 regardless of whether the needle 1 is moving forward or backward.
This connection may be made only when the needle 1 is moved forward, and this connection may be cut off when the needle 1 is retracted.

Next, the embodiment of the invention of claim 2 is shown in FIG.
6 and FIG.

Basically, it is the same as the fluid injection / recovery device according to the first aspect of the invention described with reference to FIGS. The differences are the following three points.

The first point is that the needle pin 20 is not provided, and the fine hole formed in the axial direction of the central portion of the needle 1 is used as the injection path 27.
That is the point. The second point is that the recovery passage 30 is formed by not making a groove on the outer circumference of the needle 1 but by making the diameter from the tip of the needle 1 to the middle to be considerably smaller than the inner diameter of the sleeve 5. Third point is needle 1
Is that the piston rod 12 is integrated (however, the connection as shown in FIG. 3 can also be performed).

Other than the above points, the fluid injection / recovery device according to the invention of claim 1 is the same as that described with reference to FIGS.
Also, in FIG. 6, the same reference numerals as those in FIGS. 1 to 4 denote the same members.

An advantage of the fluid injection / recovery device according to the invention of claim 2 is that the structure is simpler than that of the fluid injection / recovery device according to the invention of claim 1. However, it is difficult to form a small-diameter pore to be the injection passage 27 in the center of the needle 1, and it is not necessary to form such a pore in this respect. The fluid injection / recovery device is excellent.

Next, the operation of the fluid injection / recovery device according to the second aspect of the present invention will be described, focusing on the difference from the fluid injection / exhaust device according to the first aspect of the invention.

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.
The fluid can be injected through the connection hole 29 and the injection path 27.

When air is supplied from the air supply pipe 14 to retract the piston rod 12 (needle 1) to the limit,
As is clear from the description in FIG. 2, the piston rod 12
Since the tip end of the fluid recovery pipe 6 is retracted into the sleeve 5 to open the recovery port 6 of the sleeve 5 and the fluid recovery pipe 11 is connected to the recovery passage 30, the flow rate controller (not shown) of the fluid recovery pipe 11 is used. The fluid can be collected while adjusting the flow rate.

Whether the fluid injection / recovery device according to the first aspect of the present invention or the fluid flow rate adjusting device according to the second aspect of the present invention is used in which the fluid is not injected or the injection position is changed. When changing, the sleeve 5 may be removed and the opening 4 may be backfilled with the same material as the mold 2. An air cylinder was used as the drive source,
The drive source can be a hydraulic cylinder or other device.

[0046]

The present invention is as described above, and has the following effects.

(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 surely formed at the desired position of the product. be able to.

(2) The injection of the fluid is performed through the injection path 27, and the recovery of the fluid is different from the injection path 27.
Since it is performed through 0, there is no concern that the injection path 27 will be blocked by the reverse flow of the molten resin. Further, since the injection path 27 is narrow, the molten resin is unlikely to enter, and this also makes it more difficult for the injection path 27 to be clogged by the reverse flow of the resin.

(3) Since the recovery path 30 is wide,
The fluid can be collected speedily. Also,
The fluid can be recovered in a recovery tank or the like via the fluid recovery pipe 11, and it is possible to reduce costs by reuse while preventing waste and deterioration of the work environment due to being released into the atmosphere.

(4) If the fluid recovery pipe 11 is provided with a flow rate controller, the flow rate at the time of fluid recovery can be adjusted and ejection of one gas of the fluid can be prevented. It is possible to prevent deterioration of reproducibility.

(5) The operation of each part can be easily controlled by a computer, and automation can easily improve productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a state where a needle of a fluid injection / recovery device according to a first aspect of the invention is advanced.

FIG. 2 is a cross-sectional view of the fluid injection / recovery device shown in FIG. 1 with the needle retracted.

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.

4 is a cross-sectional view taken along the line AA in FIG.

FIG. 5 is a cross-sectional view of the fluid injection / recovery device according to the second aspect of the present invention with the needle advanced.

FIG. 6 is a sectional view taken along line BB in FIG.

[Explanation of symbols]

 1 Needle 2 Mold 3 Cavity 4 Opening 5 Sleeve 6 Collection Port 7 Block 8 Casing 9 Bolt 10 Fluid Supply Pipe 11 Fluid Recovery Pipe 12 Piston Rod 13 Air Supply Pipe 14 Air Supply Pipe 15 Anti-rotation 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 29 Connection hole 30 Recovery path 31 O-ring 32 O-ring

Claims (3)

[Claims] 1. A sleeve, which is inserted into an opening formed in a mold and has a recovery port at its tip, and a recovery path between the inner surface of the sleeve and the sleeve so that the sleeve can be moved forward and backward. When moving forward, the tip fits into the recovery port of the sleeve and the tip is exposed from the recovery port into the mold, while when retracting the recovery port is opened to communicate the recovery channel with the mold and the recovery channel to the fluid recovery pipe. A needle pin inserted into the needle having a narrow injection path that is opened at the tip of the needle and is connected to the fluid supply pipe at least when the needle advances, between the needle connected to the needle and the inner peripheral surface of the needle. A fluid injection / recovery device having: 2. A sleeve, which is inserted into an opening formed in a mold and has a recovery port at its tip, and a recovery path between the inner surface of the sleeve and the sleeve so that the sleeve can be moved forward and backward. When moving forward, the tip fits into the recovery port of the sleeve so that the tip surface faces the inside of the mold from the recovery port, and when retracting, the recovery port is opened to communicate the recovery channel with the mold and recover the fluid from the recovery channel. A fluid injection / recovery device comprising: a needle connected to a pipe, wherein a hole of the needle is composed of at least a small-diameter injection passage connected to the fluid supply pipe when the needle is advanced. 3. The fluid injection / recovery device according to claim 1, wherein the fluid recovery pipe has a flow rate controller.