JPH0829556B2 - Hot Tranna for injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an injection molding machine, in which a resin injected from an injection nozzle is provided by connecting an injection nozzle of an injection device and a resin supply hole of a mold. The present invention relates to a hot runner which is transferred while heating and is supplied to a mold.

[Conventional technology]

An injection device of an injection molding machine provided with a hot runner of this type includes a barrel with a heater in which a screw for melting a resin supplied from a hopper and transferring it horizontally is provided. Furthermore, an injection nozzle for ejecting the molten resin transferred by the screw in the horizontal direction is attached to the tip of the screw.

On the other hand, in the direction of the injection hole of the injection nozzle, a molding device including a lower mold fixed to a fixed plate and an upper mold that is movable above and below is provided. The lower mold has a resin passage communicating with the cavities formed in the two molds, with the resin supply hole opening downward.

Between such an injection device and the molding device, a hot runner is provided to transfer the resin injected from the injection hole of the injection device while heating and supply the resin to the mold. This hot runner is provided with a heater for resin heating and extends horizontally from the nozzle toward the lower side of the mold, and a nozzle mounted orthogonally to the tip of the runner body is formed into a substantially L-shape. . The runner main body is supported at its injection device side end portion so as to be swingable and slightly movable in the axial direction. Further, the runner body is provided with a resin passage communicating with the injection hole and penetrating the shaft core portion, and the resin passage is opened at the upper end of the nozzle. Further, a vertical swing cylinder is provided below the swing end of the runner body, with the working end of the piston rod abutting the lower surface of the runner body.

With this configuration, the injection device is moved in the horizontal direction, the injection nozzle is pressed against the adapter provided at the resin passage starting end of the runner body, and then the runner body is rocked by the rocking cylinder. When the oscillating end portion is raised, the nozzle at the oscillating end portion is elevated and pressed against the resin supply hole of the mold. Therefore, when the molten resin is injected from the injection nozzle of the injection device, the molten resin is heated by the heater, passes through the resin passage of the runner body and the hole of the nozzle, and is supplied from the resin supply hole into the cavity of the mold. Molding is performed.

When the molten resin is supplied to the mold by such a hot runner, the molten resin may leak from the gap between the resin supply hole of the mold and the nozzle pressed by the hole. Then, if left in this state for a long time, a large amount of leaked molten resin solidifies and becomes difficult to remove, and more parts must be removed in order to remove this,
It takes a long time and a lot of labor. Therefore, conventionally, there has been proposed a resin leakage detection device capable of minimizing the resin leakage by detecting the resin leakage at an early stage and taking measures such as adjusting the core of the nozzle.

That is, as a conventional resin leak detection device of this type, a resin tray provided around the nozzle of the hot runner is fixed to one end of a horizontal lever that swingably supports a central portion, and the limit is provided to the other end of the horizontal lever. This is a fixed striker close to the switch.Molten resin leaks and accumulates in the resin tray above a predetermined amount, and the horizontal lever tilts due to its weight, and the striker closes the limit switch contact to cause resin leakage. It is known to be configured to detect the.

[Problems to be Solved by the Invention]

However, since the conventional resin leak detection device as described above tilts the lever-like horizontal lever as described above, not only is early leak detection not possible, but resin adhesion and rust occurrence, etc. Therefore, the horizontal lever may become difficult to move, which is unreliable, and if the horizontal lever is lengthened in order to avoid this, there is a problem that the entire device becomes long and the installation space is enlarged.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a hot runner for an injection molding machine equipped with a resin leak detection device that operates smoothly and has a compact structure.

[Means for solving the problem]

In order to achieve such an object, the hot runner of the injection molding machine according to the present invention has a central through hole that is not in contact with the nozzle around the nozzle of the runner body that is pressed from below by the resin supply hole of the mold. An annular resin tray is provided and a thermocouple for resin leakage detection is provided in contact with the bottom surface of the annular tray.

[Action]

According to the present invention, when the molten resin is injected from the injection nozzle of the injection device, the molten resin passes through the resin passage of the runner main body and the hole of the nozzle while being heated by the heater, and the inside of the cavity of the mold from the resin supply hole. And is molded into the mold. At this time, if the molten resin leaks from the pressing portion of the nozzle to the mold, it will collect in the pan and the bottom surface of the pan will rise in temperature, and the thermocouple in contact with this bottom will detect this and notify the resin leak. Therefore, the resin leakage can be dealt with early.

〔Example〕

1 to 3 show an embodiment of a hot runner of an injection molding machine according to the present invention, FIG. 1 is a partially cutaway front view thereof, and FIG. 2 is a partially cutaway II view plane of FIG. FIG. 3 and FIG. 3 are enlarged vertical sectional views in the vicinity of the nozzle pressing portion.

In these figures, reference numeral 1 denotes an injection nozzle mounted on the tip of a barrel 2 of an injection device. The injection nozzle 1 is formed with the barrel 2 and the like so as to be movable back and forth in the axial direction indicated by an arrow A in FIG. There is. Then, the resin, which is transferred in the barrel 2 while being heated and melted by the heater mounted on the peripheral surface of the barrel 2 and the screw in the barrel 2, is injected from the injection nozzle 1. Further, 3 is a lower mold fixed to the fixed plate 4 via a mold mounting plate 5, and is provided in the center hole of the lower mold 3 and the support plate 6 fixed to the mold mounting plate 5. A resin supply hole 8 that communicates with a cavity provided in the lower mold 3 and an upper mold (not shown) is formed in the plate 7 that is positioned and fixed to the lower mold 3.

A hot runner, generally designated by 10, is provided between the injection nozzle 1 of the injection device and the resin supply hole 8 of the lower mold 3. The hot runner 10 includes a pair of brackets 11 fixed to the side surface 5 a of the mold mounting plate 5 in the vicinity of the nozzle 1. And each bracket 11 has a bearing
12 are fixed respectively. 13 is a rectangular plate-shaped support plate 13
It is a trunnion formed by a and a short shaft 13b protruding from both side surfaces thereof, and is rotatably supported by a bearing 12 via a bush 14. A small-diameter portion 15a, which is formed at one end of the runner main body, is inserted into the hole formed in the support plate 13a of the trunnion 13 so as to be slidably adjusted. The runner main body 15 is engaged with a groove 5b formed in the die mounting plate 5 and extends toward the resin supply hole 7, and a plurality of heaters 16 are mounted on the outer periphery thereof.

17 is a bracket fixed to the bottom surface 5c of the groove 5b,
A roller 18 attached to the swing end surface of the runner body 15 is pivotally attached to the bracket 17 via a pin 19 so as to be rotatable. In addition, the base end step portion of the runner body 15 and the trunnion
A disc spring 20 in which a spring force for pressing the swing end surface of the runner body 15 against the roller 18 is accumulated is fixed between the disc spring 13 and the runner body 13 by a nut 21 screwed into a screw portion. Then, by advancing the nozzle 1, the injection nozzle 1 is attached to the arc surface of the adapter 22 attached to the base end of the runner body 15.
Are configured to be pressed against each other.

The fixed platen 4 is located below the swinging end of the runner body 15.
A hydraulic cylinder 24 as a fluid pressure cylinder is supported by a bracket 23 fixed to the. The piston rod 25 that moves back and forth in the hydraulic cylinder 24 is formed so as to be bendable around the pin 26. The plate-like portion 25a formed at the working end of the piston rod 25 is the runner body 1
A plurality of bolts are attached to the plate-like portion 27 formed on the lower surface of the swing end of the
It is fixed at 28.

Further, a nozzle 29 which is concentric with the resin supply hole 8 is mounted on the upper surface of the swing end of the runner body 15, and the roller whose end surface is brought into pressure contact by raising the piston rod 25 of the hydraulic cylinder 24. The runner body 15 swings while rotating the nozzle 18, and the nozzle 29 is joined to the resin supply hole 8. Reference numeral 15b is a resin passage that penetrates the shaft core portion of the runner body 15 and connects the hole of the adapter 22 and the hole of the nozzle 29.

Further, a bracket 30 supported on the lower end of the hydraulic cylinder 24 is fixed with an ascending limit confirmation limit switch 31 and a descending limit confirmation limit switch 32. In addition, the striker 33, 34
Has been fixed. With this configuration,
It is possible to confirm the upper limit and the lower limit of the piston rod 25. The reference numeral 35 in FIG. 2 indicates the bracket 11
Is inserted between the side surface 5a of the mold mounting plate 5 and the runner body 15
This is a shim that adjusts the swing center of.

Further, the present apparatus is provided with a detection device for detecting leakage of the molten resin from the gap between the tip spherical surface of the nozzle 29 and the spherical surface of the plate 7. That is, around the nozzle 29, a tray 40 formed in a hollow ring shape to receive the leaked resin
Is provided by fixing the peripheral portion 40a to the step portion of the support plate 6. In the center of this saucer 40, the nozzle
A central through hole 40b that is not in contact with 29 is formed. With this configuration, when the molten resin leaks from the gap between the tip spherical surface of the nozzle 29 and the spherical surface of the plate 7, the resin is stored in the receiving tray 40 as indicated by reference numeral 41 in the figure.

Further, according to the present invention, a thermocouple 42 connected to a power source and, for example, a buzzer or a lamp is disposed below the saucer 40 in contact with the bottom surface of the saucer 40. With this configuration, the high temperature resin 41 stored in the tray 40 raises the temperature of the thermocouple 42, and the resin leak can be notified by a buzzer or a lamp.

The operation of the hot runner configured as above will be described. That is, when the barrel 2 is advanced to join the injection nozzle 1 to the hole of the adapter 22 and the hydraulic cylinder 24 is operated to advance the piston rod 25, the runner body 15 fixed to the working end of the piston rod 25 is removed. The roller 29 is slidably in contact with the roller 18 and is swung about the trunnion 13 while rotating the roller 18, and the nozzle 29 is pressed against the resin supply hole 8. Since the piston rod 25 bends when the runner body 15 swings, the runner body 15 swings smoothly even if the plate-shaped portions 25a and 27 are fixed. Further, since the swing end surface of the runner body 15 is pressed against the rotating roller 18, the swing end surface and the roller 18 are not worn. When the nozzle 29 is joined to the resin supply hole 8, the striker 33 contacts the limit switch 31 and the rising limit is confirmed.

After this, when the resin is supplied from the hopper of the injection device and the screw is rotated, the resin is melted and the nozzle 1
Is ejected from. This molten resin is contained in the resin passage 15b and the nozzle 2
It is injected from the resin supply hole 8 into the cavity of the mold through 9 and is solidified to obtain a molded product.

In the present embodiment, when the runner body 15 is thermally expanded, its swinging end face is pressed against the roller 18 and its movement to the left in the figure is restricted, so that the runner body 15 has the disc spring 20.
To the right in the figure so as to compress, and the thermal expansion is absorbed by the disc spring 20. Therefore, the core of the nozzle 29 and the core of the resin supply hole 8 will not be out of alignment.

In the injection molding machine configured as described above, when the molten resin leaks from the gap between the tip spherical surface of the nozzle 29 and the spherical surface of the plate 7 when the molten resin is injected into the mold cavity,
As indicated by reference numeral 41 in the figure, the resin is stored in the receiving tray 40, and the bottom surface of the receiving tray 40 is in contact with a thermocouple 42 as a leak detection device for the molten resin, which is heated by the high temperature resin 41. Since the temperature is raised and the resin leak is notified by a buzzer, a lamp or the like, the operator can know the resin leak relatively early.

In this case, the resin in the tray 41 can be easily removed by floating the lower mold 3 with a fork of a forklift. Also, bolt 28 and bracket 11
By removing the hot runner 10, the hot runner 10 itself can be easily removed.

〔The invention's effect〕

As is clear from the above description, according to the hot runner of the injection molding machine of the present invention, the center through hole that is not in contact with the nozzle is provided around the nozzle of the runner body that is pressed from below by the resin supply hole of the mold. Since the annular resin tray having the above is provided and the thermocouple for detecting the resin leak which is in contact with the bottom surface of the resin tray is provided, the following excellent effects are exhibited.

That is, according to the present invention, the temperature of the thermocouple is raised by accumulating the molten resin leaked from the nozzle pressure contact portion to the mold in the receiving tray, thereby notifying the operator of the resin leak condition, so that the resin leak can be promptly detected. Can also correspond to
Even if the resin leaks like this, it can be easily removed in a short time, improving the operating rate of the machine and
You can reduce the effort.

[Brief description of drawings]

1 to 3 show an embodiment of a hot runner of an injection molding machine according to the present invention, FIG. 1 is a partially cutaway front view, and FIG. 2 is a direction of arrow II in FIG. FIG. 3 is an enlarged vertical sectional view of the vicinity of the nozzle pressing portion viewed from the direction of arrow III in FIG. 2. 3 ... Lower mold, 8 ... Resin supply hole, 10 ... Hot runner, 15 ... Runner body, 29 ... Nozzle, 40 ... Sauce, 41
…… Resin, 42 …… Thermocouple.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Shown 60-166521 (JP, U) Shown 60-142914 (JP, U) Shown 53-69462 (JP, U) Shown Flat 3- 116911 (JP, U) Actual opening 2-97012 (JP, U) Actual opening Flat 1-175806 (JP, U) Actual opening Sho 63-82520 (JP, U)

Claims (1)

[Claims] 1. A ring-shaped leaking resin tray having a central through hole that is not in contact with the nozzle is provided around the nozzle of the runner body that is pressed from below by the resin feed hole of the mold, and the bottom surface of the tray is provided. A hot runner for an injection molding machine, which is provided with a thermocouple in contact therewith.