JPH07314498A - Nozzle device for injection molding machine - Google Patents

Abstract

PURPOSE:To prevent the delay of switching, a failure such as a flash, and the damage of a nozzle, etc. CONSTITUTION:An inner nozzle 2 and a needle 3 are advanced by hydraulic cylinders 26, 27 to dispose the front end faces 2f, 3c of closed shafts 2e, 3a engaged with the injection ports 1a, 2a of nozzles 1, 2 inside the opening surfaces 1e, 2g of the ports 1a, 2a in the state that the cylinders 26, 27 are arrived at the advanced ends to be stopped, and the nozzles 1, 2 are closed only by engaging the shafts 2e, 3a with the ports 1a, 2a. The shafts 2e, 3a are short to reduce a switching stroke, and since the nozzle 2 and the needle 3 are not brought into contact with the nozzles 1, 2, the above purpose is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle device of an injection molding machine for injecting a molten resin into a mold.

[0002]

2. Description of the Related Art As a nozzle device of an injection molding machine, one shown in FIGS. 7 and 8 is known. The nozzle device of FIG. 7 is for preventing resin leakage in an ordinary single-material injection molding machine. To explain this, a nozzle device having an injection port 11a at the front end (the left side in the figure is the front) will be described. , The needle 12 which is brought into contact with the inner wall (valve seat) 11b of the injection port 11a and closes the injection port 11a,
1, the needle 12 is inserted into the piston rod 15b of the hydraulic cylinder 15 through a lever 14 which is inserted concentrically with the pin 1 so as to be movable in the axial direction and is rotated around a pin 13.
And the injection port 11a is closed (see Japanese Utility Model Laid-Open No. 59-160216). The piston rod 15b is connected to the lever 14 by a pin 16.

Further, FIG. 8 shows a nozzle device of an injection molding machine capable of performing sandwich molding by simultaneously or separately injecting two or more kinds of resins having different kinds and colors into one mold. . This nozzle device has an injection port 1 at the front end.
An inner nozzle 2 having an injection port 2a at the front end and having a front end that is in contact with the valve seat 1b of the outer nozzle 1 to close the outer nozzle 1 has an outer nozzle 1 having a, and a flow chamber C1 communicating with the injection device 4 1 is formed between the inner nozzle 2 and the outer nozzle 1 so as to be concentric with the outer nozzle 1 and axially movable, and the inner nozzle 2 has an injection port 2a of the inner nozzle 2 having the same length as the injection port 2a. A needle 3 for fitting the closing shaft 3a over its entire length to close the inner nozzle 2 forms a flow chamber C2 communicating with the injection device 5 with the inner nozzle 2 so as to be concentric with the inner nozzle 2 and axially. It is movably inserted.

The inner nozzle 2 is provided with a hydraulic cylinder 6 for moving the inner nozzle 2 in the axial direction with respect to the outer nozzle 1, and the needle 3 is provided with the hydraulic cylinder 6 in the axial direction. A hydraulic cylinder 7 is attached to move it relative to.

The hydraulic cylinder 6 has a cylinder body 6a.
Is directly connected to the rear end of the outer nozzle 1, and the piston rod 6b is directly connected to the rear end of the inner nozzle 2. Also,
The hydraulic cylinder 7 is provided with its cylinder body 7 a formed at the rear end of the inner nozzle 2 and its piston rod 7 b directly connected to the rear end of the needle 3. Then, the injection device 4 communicates with the flow chamber C1 through the flow hole 1c formed in the outer nozzle 1 and the groove 2c formed in the inner nozzle 2, and the injection device 5 is formed in the nozzles 1 and 2. It has a structure that communicates with the flow chamber C2 through the flow holes 1d and 2d and the groove 3d formed in the needle 3.

In this nozzle device, when the injection device 4 is operated to inject the resin, the solenoid a of the electromagnetic valve 8 is excited to retract the inner nozzle 2 by the drive cylinder 6 and thereby the valve seat of the outer nozzle 1 is moved. The inner nozzle 2 is separated from 1b, and the injection port 1a of the outer nozzle 1 is opened as shown in FIG.

When the resin is injected by the operation of the injection device 5, the solenoid a of the solenoid valve 8 is demagnetized, and the inner nozzle 2 is moved forward by the hydraulic cylinder 6 so as to contact the valve seat 1b of the outer nozzle 1. The outer nozzle 1 is closed to energize the solenoid b of the solenoid valve 9 to excite the hydraulic cylinder 7.
The needle 3 is retracted to remove the closing shaft 3a from the ejection port 2a of the inner nozzle 2 and open the ejection port 2a of the inner nozzle 2 (Japanese Utility Model Laid-Open No. 63-161811). Such a nozzle device is disclosed in JP-A-60-2123.
No. 15, Japanese Patent Publication No. 4-84654, Japanese Patent Publication No. 55
-45374 is also described.

[0008]

Nozzle 11 of FIG. 7,
Since the outer nozzle 1 of FIG. 8 is configured to be closed by the contact of the needle 12 or the inner nozzle 2 with the valve seats 11b and 1b, the outputs of the cylinders 15 and 6 act on the valve seats 11b and 1b. And the valve seats 11b and 1b
There is a problem that the etc. are easily damaged. Cylinder 15,6
However, if the injection pressure of the resin is high, the injection ports 11a and 1a cannot be completely closed.

In the case of the inner nozzle 2 of FIG. 8, an injection port 2a
Since the closing shaft 3a is configured to be closed by fitting the closing shaft 3a to the above, the above problem does not occur unless the root portion of the closing shaft 3a of the needle 3 is brought into contact with the inner side wall 2b of the injection port 2a. However, since the closing shaft 3a having the same length as the ejection port 2a is fitted over the entire length of the ejection port 2a to close the ejection port 2a, there are the following problems.

Since a long opening / closing stroke of the closing shaft 3a is required, an operation delay is likely to occur. After the pressure-holding process is completed and the resin in the cavity is solidified, the needle 3 is moved to close the injection port 2a, but at this time, the amount of resin pushed out from the injection port 2a by the closing operation of the closing shaft 3a is large, It is easy to cause various troubles such as burrs protruding from the nozzle touch part and being forced into the runner or sprue.

When the closing shaft 3a is pulled out from the injection port 2a, the resin pressure applied around the closing shaft 3a momentarily becomes unbalanced due to the start of the injection of the resin from the injection port 2a, and the closing shaft 3a is bent. It works, but the closing shaft 3a
If the length is long as described above, it may be broken due to the bending action.

It is an object of the present invention to provide a nozzle device for an injection molding machine, which does not cause a delay in operation and burrs and does not damage the nozzle and needle due to driving pressure or resin pressure.

[0013]

In order to achieve the above object, the present invention is directed to a linear nozzle which is fitted into the injection nozzle and closes the injection nozzle in a nozzle having a linear injection nozzle at the front end. A needle having a closed shaft formed at the front end is inserted concentrically with the nozzle so as to be movable in the axial direction, and the needle is provided with a moving drive device for advancing the needle in the axial direction. In the nozzle device of the molding machine,
The needle is moved forward by the movement drive device and is fitted to the ejection opening of the nozzle so that the front end face of the closing shaft is located closer to the forward end than the opening end of the ejection opening when the movement drive device reaches the forward operation end. The nozzle is positioned inside and stopped, and the nozzle is closed only by fitting the closing shaft into the injection port. The needle can also be an inner nozzle with an outlet in the closure shaft.

[0014]

Since the length of the closing shaft and the opening / closing stroke thereof can be shortened, it is possible to eliminate the operation delay and the trouble such as burrs due to the extrusion of the resin from the injection port, and the closing shaft due to the resin pressure. Can be prevented from being cut. Further, since the needle is not in contact with the valve seat to close the nozzle, the nozzle or the like is not damaged by the driving pressure of the moving drive device.

[0015]

1 and 2 show an embodiment of a nozzle device of an injection molding machine according to the present invention. The same members as those in FIG. 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

An injection port 11c is linearly formed at the front end of the nozzle 11, and a closing shaft 12 is provided at the front end of the needle 12.
a is provided linearly. Injection port 11c and closing shaft 1
2a and 2a both have a circular cross section, and their center lines coincide with each other. The closing shaft 12a is fitted into the injection port 11c and closes the injection port 11c. The diameter of the closing shaft 12a is slightly smaller than the diameter of the injection port 11c to the extent that resin leakage does not occur, and the fitting length of the closing shaft 12a is small. It is made sufficiently shorter than the exit 11c.

The hydraulic cylinder (moving drive device) 15 is
When the needle 12 is moved forward and reaches the forward operation end, a part of the closing shaft 12a is fitted into the injection port 11c and stopped (see FIG. 1), and at the backward operation end, as shown in FIG. The stroke is determined so that can be completely withdrawn from the ejection port 11c to open the ejection port 11c.

Next, the operation of the nozzle device of the injection molding machine according to the present invention having the above structure will be described. Hydraulic cylinder 1
When 5 is contracted, the needle 12 advances by the rotation of the lever 14 connected to the rod 15b of the piston 15a by the pin 16, and the closing shaft 12a is fitted into the injection port 11c and closed.

In this case, since the stroke of the hydraulic cylinder 15 is determined as described above, the needle 12
Is a state in which the front end surface 12b of the closing shaft 12a is opened to the opening surface 11d of the injection port 11c while the hydraulic cylinder 15 reaches the forward operation end.
Close the nozzle 11 only by fitting the closing shaft 12a to the injection port 11c without contacting the nozzle 11 with the tapered portion 12c formed at the base of the closing shaft 12a. Becomes

Therefore, the driving force of the hydraulic cylinder 15 is not applied to the nozzle 11 and damage to the nozzle 11 and the like is prevented. Further, since the opening / closing stroke of the needle 12 is short, there is no time delay, and when the injection port 11c is closed, the injection shaft 11c is closed by the closing shaft 12a.
Since the amount of resin extruded from the resin is small, problems such as burrs can be prevented. Since the closing shaft 12a is short, it is not damaged by the resin pressure. The hydraulic cylinder 15 can be another moving drive device using an electromagnet, a motor, or the like.

FIG. 3 shows a second embodiment of the present invention. In this nozzle device, a front portion 11e of the injection port 11c into which the closing shaft 12a is fitted is formed in a taper shape that opens outward. In the case of this embodiment, it becomes easy to take out the resin remaining in the front portion 11e of the injection port 11c together with the product or the like. The other structure is the same as that of the nozzle device of FIGS.

4 to 6 show a third embodiment of the nozzle device of the injection molding machine according to the present invention. It should be noted that the same members and the like as those in FIG. 8 are denoted by the same reference numerals and detailed description thereof will be omitted.

Outlet nozzles 1a and 2a are linearly formed at the front ends of the outer nozzle 1 and the inner nozzle 2, and the inner nozzle 2
On the front end of the needle 3, closing shafts 2e and 3a are linearly provided. The injection ports 1a, 2a and the closing shafts 2e, 3a are both circular in cross section and have their center lines aligned with each other. The closing shaft 2e is on the injection port 1a, and the closing shaft 3a is on the injection port 2a.
To fit them in and close them,
The diameters of the closing shafts 2e, 3a are slightly smaller than the inner diameters of the injection ports 1a, 2a to the extent that resin leakage does not occur, and the lengths thereof are made sufficiently shorter than the injection ports 1a, 2a. The inner nozzle 2 functions as a needle for the outer nozzle 1.

The hydraulic cylinder (moving drive device) 26 is
When the inner nozzle 2 is advanced and reaches the forward operation end, a part of the closing shaft 2e is fitted into the injection port 1a and stopped (see FIGS. 4 and 5), and at the backward operation end, as shown in FIG. ,
The stroke of the closing shaft 2e is determined so that the closing shaft 2e can be completely pulled out from the ejection opening 1a to open the ejection opening 1a.

Similarly, in the other hydraulic cylinder (moving drive device) 27, the needle 3 is moved forward, and when the needle reaches the forward operation end, a part of the closed shaft 3a is fitted into the injection port 2a and stopped ( (See FIGS. 4 and 6), and at the retreating operation end, as shown in FIG. 5, the stroke is determined so that the closing shaft 3a can be completely pulled out from the ejection opening 2a to open the ejection opening 2a. There is.

In the nozzle device of this embodiment, when the hydraulic cylinders 26 and 27 are extended, the inner nozzle 2 and the needle 3 are advanced and the closing shafts 2e and 3a are connected to the injection ports 1a and 2 respectively.
Fit in a and close it. In this case, since the strokes of the hydraulic cylinders 26 and 27 are determined as described above, just like the nozzle device of the first embodiment, the inner cylinder 2 and the needle 3 are moved forward by the hydraulic cylinders 26 and 27. The front end surface 2f of the closing shafts 2e, 3a in a state of reaching the end,
3c is positioned inside the opening faces 1e, 2g of the ejection openings 1a, 2a and stopped, and the taper portions 2h, 3d formed at the base portions of the closing shafts 2e, 3a are brought into contact with the nozzles 1, 2. Without the closing shafts 2e for the outlets 1a, 2a,
The nozzles 1 and 2 are closed only by fitting 3a.

Therefore, also in this embodiment, the same effect as that of the nozzle device of the first embodiment can be obtained. The configuration of FIG. 3 can be introduced into this nozzle device. Further, the number of fitting stages of the nozzles 1 and 2 can be three or more. Also in this case, the inner nozzle functions as a needle with respect to the nozzle outside the nozzle as described above. In the case of a multi-stage nozzle device, if necessary, for example, the closing shaft 3a is provided over the entire length of the injection port 2a.
All the outlets 1 such that
The a, 2a and the closed shafts 2e, 3a do not have to have the configuration of the present invention.

[0028]

As described above, the nozzle device of the injection molding machine according to the present invention is a straight line which is fitted into the injection port and closes the injection port in the nozzle having the linear injection port at the front end. A needle having a closed shaft in the shape of a front end is inserted concentrically with the nozzle and movably in the axial direction,
In a nozzle device of an injection molding machine in which a moving drive device for advancing the needle in the axial direction is attached to the needle, the needle is advanced by the moving drive device and fitted into an injection port of the nozzle. The front end face of the closed shaft is positioned inside the opening end of the injection port and stopped when the moving drive device reaches the forward operation end, and the nozzle is locked only by fitting the closing shaft into the injection port. Since it is configured to be closed, the length of the closing shaft and the opening / closing stroke can be shortened. Therefore, there are no problems such as operation delay and burrs, and the nozzle and needle are not damaged by the driving force of the moving driving device or the resin pressure.

[Brief description of drawings]

FIG. 1 is a sectional view in a closed state showing an embodiment of a nozzle device of an injection molding machine according to the present invention.

FIG. 2 is likewise a sectional view in an open state.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

5 is a cross-sectional view showing a retracted state of a needle of the nozzle device of FIG.

FIG. 6 is likewise a sectional view showing a retracted state of the inner nozzle.

FIG. 7 is a sectional view showing a nozzle device of a conventional injection molding machine.

FIG. 8 is a cross-sectional view of another conventional nozzle device.

[Explanation of symbols]

 1 Outer Nozzle 1a Injection Port 2 Inner Nozzle (Needle) 2a Injection Port 2e Closure Shaft 3 Needle 3a Closure Shaft 11 Nozzle 11c Injection Port 15 Hydraulic Cylinder (Moving Drive Device) 26 Hydraulic Cylinder (Moving Drive Device) 27 Hydraulic Cylinder ( Drive device for movement)

Claims (2)

[Claims] 1. A needle having a straight closed shaft, which is fitted into the injection port and closes the injection port, formed at the front end in a nozzle having a linear injection port at the front end, is concentric with the nozzle. In a nozzle device of an injection molding machine, which is inserted movably in the axial direction and has a moving drive device for advancing the needle in the axial direction, the needle is moved forward by the moving drive device. The front end face of the closed shaft fitted into the injection port of the nozzle,
In the state where the moving drive device reaches the forward operation end, the moving drive device is positioned inside the opening end of the ejection port and stopped, and the nozzle is closed only by fitting the closing shaft into the ejection port. Nozzle device of injection molding machine. 2. The nozzle device for an injection molding machine according to claim 1, wherein the needle is an inner nozzle having an injection port on a closed shaft.