JPH0369327A - Mold for injection molding - Google Patents

Abstract

PURPOSE:To ensure the positional relation between a movable rod and a gate, and prevent the movable rod and the gate from contact-interference with each other by providing a resin conduit communicating to a cavity via the gate between a nozzle main body and a guide bush, and also providing axially and movably a rod which serves to open and close the gate. CONSTITUTION:In an injection molding mold, a movable rod 33 is moved along the axial line and the open and close operations of a gate 31 is effected by a gate closing part 35. The movable rod 33 is support-guided by means of a guide bush 32 and acts to conduct the open and close of the gate 31 smoothly without deviation in the top end of the movable rod 33. And, when the gate 31 opens, molten resin which has passed through a resin conduit 20 within a manifold 15 and the inclined hole 19 of a nozzle main body 17 stays in the top end part of a central hole 18 of the nozzle main body 17 from a recession 37 formed on the outer periphery of a guide bush 32 via a spiral resin conduit 38 formed between a pair of protrusions 36, and then injected well into a cavity via the gate 31.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection mold equipped with a movable rod (torpedo) that opens and closes a gate.

[Conventional technology]

Generally, in this type of injection mold, if there is even a slight deviation in the positional accuracy of the torpedo, the torpedo will come into contact with the gate, which will shorten the life of the gate.

For example, Japanese Unexamined Patent Publication No. 59-150736 proposes a configuration in which a guide member for regulating the position of the tip of the tobead is provided in the mold.

FIG. 7 shows an example of an injection molding mold according to this proposal, in which reference numeral 1 is a fixed mold plate, 2 is a movable mold plate, 3 is a gate, 4 is a cavity, 5 is a bush equipped with a band heater 6, and 7 is a resin. The passageway 8 is a tobeid which is operated to open and close the gate 3, which is raised and lowered.

A cylindrical guide member 9 is fitted into the lower end of the pusher 5 facing the gate 3. This guide member 9 is
As shown in FIG. 8, the inner wall surface 9B has a conical shape that narrows downward, and as shown in FIG.
Three grooves 9A extending in the vertical direction are formed 120 degrees apart from each other.

As a result, in the above injection mold, Torpedo 8
Even if vibration occurs when the gate 3 is lowered and the gate 3 is closed, the side surface of the tip end of the torpedo 8 contacts the tapered surface 9B of the guide member 9 and its position is corrected, preventing the gate 3 from entering the gate 3. It is said that there is no.

[Problem to be solved by the invention]

However, in the above-mentioned conventional injection mold, the guide member 9 is integrally fixed to the bush 5 which is directly heated by the band heater 6 and undergoes rapid temperature changes.
Due to the thermal expansion of the bushing 5, the position of the bottom end of the bushing 5 unexpectedly changes not only in the vertical direction but also in the horizontal direction, and the relative position of the guide member 9 and the gate 3 itself may become incorrect. There was a problem in that contact between the torpedo 3 and the torpedo 8 could not be completely prevented.

The present invention has been made in view of the above circumstances, and its purpose is to reliably maintain the positional relationship between the movable rod and the gate and completely prevent contact interference between the movable rod and the gate. Our goal is to provide injection molds that can.

[Means for solving the problem] In order to achieve the above object, the injection molded metal of the present invention has the following features:
A cavity is formed between a pair of mold plates, a nozzle body is provided in one of the mold plates, a guide bush is provided in the nozzle body, and a gate is provided between the nozzle body and the guide bush. A resin passage communicating with the cavity is provided, and a movable rod for opening and closing the gate is provided within the guide bush so as to be movable in the axial direction thereof.

[Effect]

In the injection molding mold of the present invention, molten resin is injected into the cavity from the gate through the resin passage formed by the nozzle body and the guide bushing, and the movable rod that opens and closes the gate is the guide bushing. Move inside the guide bush guided by the bush.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 6.

FIG. 1 is a sectional view showing an embodiment of the injection molding die of the present invention, and in this figure, reference numeral 10 indicates a fixed mold plate. A movable plate 11 is provided opposite to the fixed mold plate 10 so as to be openable and closable. A cavity 12 in the shape of a molded product is formed between these templates 10 and 11. The fixed template 10 is the first. The second support plate 13, 14 is fixed to the fixed mounting plate, and the movable mold plate 11 is fixed to the movable mounting plate via the support plate. In addition, the second receiving plate 1
A manifold 15 is disposed between 4 and the fixed mounting plate, and the outer periphery of this manifold 15 is covered with a heat insulating material 16.

The fixed template 10, the first. A cylindrical nozzle main body 17 is mounted inside the second receiving plate 13.14, and the tip of this nozzle main body 17 has an inner circumference that gradually reduces in diameter and an outer circumference that is tapered. ing. A slanted hole 19 for supplying molten resin is formed obliquely from the base end surface of the nozzle body 17 to the center hole 18 , and this slanted hole 19 communicates with a resin passage 20 in the manifold 15 .

Further, a mounting groove 21 is formed in the outer circumference of the nozzle body 17, and a temperature sensor 22 is mounted in this mounting groove 21. A coil heater 23 is disposed on the outer periphery of the nozzle body 17, and a cylindrical heater cover 24 covers the outer periphery of the coil heater 23. Further, a recess 25 is formed at the base end of the heater cover 24, and the temperature sensor 22 and coil heater 23 are connected through the recess 25.
i26, 27 are led out. A ring-shaped groove 28 is formed in the stepped portion of the heater cover 24, and four arc-shaped deep grooves 29 are formed in the groove 28 at equal intervals.

Furthermore, the stepped portion of the heater cover 24 is fitted into the mounting recess 30 of the fixed mold plate lO whose diameter is reduced in a stepped manner, and the tip of the heater cover 24 and the conical tip of the nozzle body 17 are , are provided in the mounting recess 30 of the fixed mold plate 10 with a predetermined gap maintained therebetween. The center of the mounting recess 30 is connected to a gate 3 communicating with the cavity 12.
It is said to be 1.

A cylindrical guide bushing 32 is attached to the center hole 18 of the nozzle body 17 from the base end side, and a movable rod 33 for opening and closing the gate 31 is inside the guide bushing 32. It is provided so as to be movable in the axial direction. A bush 34 is mounted inside the guide pusher L32. Further, the distal end of the movable rod 33 is formed into a cylindrical gate closing portion 35 having a diameter slightly smaller than the opening diameter of the gate 31 through a conical portion.

Furthermore, a pair of spiral protrusions 36 are formed on the outer circumference of the guide bushing 32 from the middle part to the distal end, as shown in FIGS. A recess 37 is formed near the base end of 36 . This concave portion 37 and the inclined hole 19 of the nozzle body 17 are arranged to face each other, and the space between the nozzle body 17 and the guide bushing 32, partitioned by the two protrusions 36, is filled with molten resin. The resin passage 38 is

In the injection mold configured as described above, the movable rod 33 is moved along its axis, and the gate 31 is opened and closed by the gate closing portion 35 at the tip of the movable rod 33. In this case, the movable rod 33 reciprocates inside the guide bush 32, and the movement is similar to that of the guide bush 1. The gate 32 (because it is supported and guided in this way, the tip of the gate 33 does not shake, and the gate 33 is smoothly moved)
1 can be opened and closed. Furthermore, when the gate 31 is opened, the molten phase resin that has passed through the resin passage 20° in the manifold 15 and the inclined hole 19 of the nozzle body 17 flows from the recess 37 formed on the outer periphery of the guide pusher L32.
The resin passes through the spiral resin passage 38 formed between the pair of protrusions 36, collects at the tip of the center hole 18 of the nozzle body 17, and is smoothly injected into the cavity 12 via the gate 31.

〔Effect of the invention〕

As explained above, in the injection molding mold of the present invention, a cavity is formed between a pair of template plates, a nozzle body is provided in one of the template plates, and a guide bush is provided in the nozzle body. In addition, a resin passage communicating with the cavity via a gate is provided between the nozzle body and the guide bushing, and a movable rod that opens and closes the gate is movable in the axial direction within the guide bush. Since the molten resin is injected into the cavity from the gate through the resin passage formed by the nozzle body and the guide bushing, and the movable rod that opens and closes the gate is connected to the guide bushing. By being guided and moving within the guide bush, the positional relationship between the movable rod and the gate can be maintained reliably, and contact interference between the movable rod and the gate can be completely prevented. The molten resin injected into the cavity can be smoothly supplied.

[Brief explanation of drawings]

1 to 6 show an embodiment of the present invention,
Fig. 1 is a sectional view, Figs. 2 to 5 show an example of a guide bushing, Fig. 2 is a plan view, Fig. 3 is a front view, Fig. 4 is a sectional view, and Fig. 5 is a sectional view. A side view, FIG. 6 is a sectional view showing an example of the nozzle body, FIGS. 7 to 9 show a conventional injection mold, FIG. 7 is a sectional view, and FIG. 8 is a sectional view of main parts. 9 are bottom views of the bushing part. 10... Fixed template, 11... Movable template, 12...
Cavity, 17... Nozzle body, 31... Gate, 32 Guide bushing, 33... Movable rod, 38...
...Resin passage.

Claims (1)

[Claims] A cavity is formed between a pair of mold plates, a nozzle body is provided in one of the mold plates, a guide bush is provided in the nozzle body, and a gate is provided between the nozzle body and the guide bush. An injection molding mold characterized in that a resin passage communicating with the cavity is provided, and a movable rod for opening and closing the gate is provided in the guide bush so as to be movable in the axial direction thereof.