JPH0630421Y2 - Nozzle dripping prevention device for injection molding machine - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle dripping prevention device for an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a hopper 1 is provided at a root end and an injection nozzle (hereinafter simply referred to as a nozzle) is provided at a tip.
2, a heating cylinder 4 having a screw 3 rotatably inside and axially movable back and forth is provided in a main body 5 so as to be movable forward and backward, and is provided in front of the nozzle 2 on the main body 5 with an interval. A movable platen 9 supported by a tie rod 8 and movably by a mold clamping cylinder is provided between a fixed platen 6 and an end plate 7, and a mold attached to the movable platen 9 and the fixed platen 6. There is known an injection molding machine in which the resin supplied from the hopper 1 into the heating cylinder 4 is injected into the inside of the nozzle 10 from the nozzle 2 to perform molding. This injection molding machine is equipped with a nozzle with a shut-off valve mechanism built into the injection device in order to obtain a high-quality injection-molded product in order to uniformly melt the resin, and to apply pressure (back pressure) in the heating cylinder 4. There is a method in which the resin is plasticized while being loaded.
The shut-off valve mechanism moves a needle valve in its axial direction by rotating a lever that rotates about a fulcrum via a rod that reciprocates by a hydraulic cylinder or the like, and a hole at the tip of the nozzle. Is opened and closed. However, in the thermosetting resin injection molding machine, when the shutoff valve mechanism is provided in the nozzle portion, the resin may stay in the nozzle portion and remain and harden, so the shutoff valve mechanism is adopted. I can't help but use an open nozzle. In the figure, 3a is an injection cylinder.

[0003]

However, in the above thermosetting resin injection molding machine, the open nozzle is adopted as described above, and this injection molding machine must have a nozzle within one cycle of the stroke. Since there is a retreat operation and a spinal pressure applied to the screw is also necessary for the measurement stability of the amount of resin material, when the nozzle retreats, the phenomenon of resin dripping from the nozzle (leakage) is likely to occur. In particular, in the thermosetting parting injection molding machine, since the resin retention in the heating cylinder 4 is prevented, the metering operation is performed immediately before the injection (at this time, the nozzle is retracted). More likely to happen.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a nozzle dripping prevention device for an injection molding machine which can prevent dripping of a molten resin from a nozzle.

[0005]

The present invention has the following structure in order to achieve the above object. That is, a resin material is supplied and plasticized in a heating cylinder provided so as to be movable back and forth with respect to a mold, and the plasticized resin material is
In an injection molding machine that performs molding by injecting into the mold from an open nozzle at the tip of the heating cylinder by a screw provided in the heating cylinder, the nozzle tip of the nozzle retracted position separated from the mold by a predetermined distance. In addition, a nozzle hole closing member that is provided so as to be capable of advancing and retracting in the axial direction of the nozzle and movable in a direction intersecting with the axis of the nozzle is provided so as to be in close contact with the nozzle.

[0006]

According to the above construction, when injection molding is performed, the nozzle hole closing member approaches the nozzle in the retracted position and closely contacts the tip of the nozzle to close the nozzle hole.
In this state, the resin material is supplied to the inside of the heating cylinder for plasticization, and when the plasticization is completed, the nozzle hole closing member retracts from the nozzle, and then the heating cylinder advances and the metal mold is closed. Nozzle touch is performed on the mold. Next, the screw advances and the molten resin material is injected from the nozzle into the cavity in the mold. In this way, since the resin material is plasticized in the heating cylinder in the state where the nozzle hole is closed by the nozzle hole closing member, at this time,
The resin material that has been melted and transferred to the nozzle side does not leak from the open nozzle even if the nozzle is an open nozzle, so that the so-called dripping phenomenon is reliably prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, the same parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. In FIG. 3, reference numeral 11 denotes a main body of a thermosetting resin injection molding machine, and a base 12 is mounted on the main body 11 by a plurality of bolts. A support member 14 to which the heating cylinder 4 is connected is supported on the base 12 so as to be movable back and forth (left and right in FIG. 3) via a guide member 14, and is attached to the base 12 and the support member 14. When the feed cylinder 13 is driven, the heating cylinder 4 is fixed to the fixed plate 6
It is designed to approach and separate from.

A hook 15 is attached to the end surface of the main body 11 on the stationary plate 6 side.
As shown in FIG. 2, a pair of guide cylinders 16 and 16 are attached to the support plate 15a so as to be separated from each other and penetrate the support plate 15a and fixed vertically. A vertical drive cylinder (air cylinder) 18 is located in the middle of the pair of guide cylinders 16 and 16 on the support plate 15a of the bracket 15, and its piston rod 18a is connected to the connecting plate 1a.
It penetrates upwards 7 and is attached in a drooping shape. The pair of guide tubes 16 and 16 include rods 19 and 19 respectively.
Is vertically slidably inserted. These rods 19,
The upper end of 19 is connected by an up-and-down moving plate 20 provided above the support plate 15a and in parallel with the support plate 15a. The lower ends of the pair of rods 19, 19 are connected by a connecting plate 17. A mounting member 21 is provided on the lower surface of the vertical moving plate 20.
The piston rod 18a of the vertical drive cylinder 18 is attached to the attachment member 21.
Therefore, the up-and-down moving plate 20 is moved up and down by the expansion and contraction operation of the up-and-down drive cylinder 18.

A front-rear drive cylinder (air cylinder) 23 is attached to the vertical moving plate 20 so as to be oriented in the axial direction of the heating cylinder 4 and have its piston rod positioned on the nozzle 2 side. At the center of the end face of the front end portion (nozzle hole closing member) of the piston rod of the front-rear drive cylinder 23, a spherical recess 24 matching the front end face of the nozzle 2 is formed. A hook-shaped pawl 22 is attached to the upper surface of the piston rod of the front-rear drive cylinder 23. The tip of the claw 22 is directed downward. On the other hand, below the backward end of the nozzle 2, an attached resin removing tool having a rotary tool 25 whose rotary axis is aligned with the axis of the front-rear drive cylinder 23 at the lower limit position of the vertical drive cylinder 18,
It is attached to a fixed portion such as the bracket 15 or the main body 11. The tip of the rotary tool 25 is a convex blade portion 26 formed on a spherical surface having substantially the same curvature as the concave portion 24 at the tip of the piston rod of the front-rear drive cylinder 23. 1 and 3, 27 is a rib for reinforcing the bracket 15, and 3b in FIG. 3 is a rotary drive device for a screw provided in the heating cylinder 4.

However, when injection molding is performed, the mold is closed and clamped, and the upper and lower parts in the contracted state are in the retracted position in which the nozzle is separated from the mold by a predetermined distance. When the drive cylinder 18 is extended, the axis of the front-rear drive cylinder 23 is located on the same axis as the axis of the heating cylinder 4. After that, the front-rear drive cylinder 23 is extended and the recess 24 on the end face of the piston rod is
The nozzle hole is closed closely to the tip of the nozzle 2. next,
The screw 3 in the heating cylinder 4 rotates, a resin material is supplied into the heating cylinder 4, the resin material is transferred to the nozzle 2 side of the heating cylinder 4 while being kneaded and melted, and transferred to the tip side of the screw 3. The screw 3 is pushed back by the pressure of the molten resin, the molten resin is measured by the retracted distance of the pushed-back screw 3, and when the screw 3 reaches the set position, the rotation of the screw 3 is stopped.
Here, the front and rear drive cylinder 23 and the vertical drive cylinder 1
8 sequentially contracts, the axis of the front-rear drive cylinder 23 is located on the axis of the rotary tool 25, and the front-rear drive cylinder 2
The piston rod 3 (nozzle hole closing member) is retracted from the front of the nozzle 2 to a position that does not hinder the forward movement of the heating cylinder 4. Next, the feed cylinder 13 is extended to move the heating cylinder 4 forward, and a nozzle touch is made to the injection resin inlet of the mold in the mold closed state. After that, the injection cylinder 3a is extended and the screw 3 is advanced,
Molten resin is injected from the nozzle 2 into the cavity in the mold.

Next, while the injection-molded product molded in the mold is cooled and solidified, the feed cylinder 13 contracts and the heating cylinder 4 moves away from the stationary platen 6 to reach the nozzle retracted position and is stopped. In the above, when the front-rear drive cylinder 23 contracts and separates from the tip of the nozzle 2,
A small amount of the molten resin may come out of the nozzle 2 due to the residual pressure of the molten resin in the heating cylinder 4 and adhere to the outside of the nozzle 2. This adhered resin is driven forward and backward when the vertical drive cylinder 18 descends. Claw 2 attached to cylinder 23
Scraped by 2. When the axis of the front-rear drive cylinder 23 is on the same axis as the axis of the rotary tool 25,
A rotary tool 25 in which the front and rear cylinders 23 extend and rotate.
When the concave surface portion of the concave portion 24 of the front and rear cylinder 23 is brought into contact with the concave portion 2 of the piston rod of the front and rear driving cylinder 23,
The resin adhering to 4 is easily removed by the rotary tool 25.

According to this embodiment, in the retracted position of the nozzle 2, with the tip of the nozzle 2 in close contact with the recess 24 of the piston rod (nozzle hole closing member) of the front and rear cylinder 23, the nozzle hole is closed, Since the resin material can be supplied into the heating cylinder 4 and transferred to the nozzle side while kneading and melting the resin material, the nozzle 2 is an open nozzle without a shut-off valve mechanism, but the nozzle 2 is used during plasticization. There is no leakage of molten resin from 2 and it is possible to reliably prevent the nasal drool phenomenon.

[0013]

According to the present invention, a resin material is supplied into a heating cylinder provided to be movable back and forth with respect to a mold to be plasticized, and the plasticized resin material is placed in the heating cylinder. In an injection molding machine that performs molding by injecting into the mold from an open nozzle at the tip of the heating cylinder by a screw provided, the nozzle is positioned in front of the nozzle at the nozzle retreat position separated from the mold by a predetermined distance. On the other hand, since the nozzle hole closing member is provided so as to be movable back and forth in the axial direction and movable in the direction intersecting with the axis of the nozzle, and the nozzle hole closing member that can be brought into close contact with the nozzle is provided, the nozzle is retracted at the retracted position. The nozzle hole closing member can be brought into close contact with the tip of the nozzle hole, and while the nozzle hole is closed by the nozzle hole closing member, the resin material is supplied into the heating cylinder to remove the resin material. It can be kneaded and melted and transferred to the nozzle side, which makes it possible to reliably prevent the nasal drooling phenomenon from this nozzle, even though the nozzle is an open nozzle, and especially for the thermosetting resin injection molding machine. It is suitable as a nozzle dripping prevention device.

[Brief description of drawings]

FIG. 1 is a side view of an essential part showing an embodiment of the present invention.

FIG. 2 is a rear view of an essential part showing an embodiment of the present invention.

FIG. 3 is a side view of an injection molding machine showing an embodiment of the present invention.

FIG. 4 is a schematic side view of a conventional injection molding machine.

[Explanation of symbols]

1 Hopper 2 Injection Nozzle (Open Nozzle) 3 Screw 4 Heating Cylinder 10 Mold 18 Upper and Lower Cylinder (Air Cylinder) 22 Claw 23 Front and Rear Cylinder (Air Cylinder) (Nozzle Hole Closure Member) 24 Recess 25 Rotating Tool

Claims (1)

[Scope of utility model registration request] 1. A resin material is supplied into a heating cylinder provided to be movable back and forth with respect to a mold to be plasticized, and the plasticized resin material is fed by a screw provided in the heating cylinder. In an injection molding machine that performs injection by molding from an open nozzle at the tip of the heating cylinder into a mold, the nozzle moves forward and backward in the axial direction with respect to the nozzle at a nozzle retracted position separated from the mold by a predetermined distance. A nozzle dripping prevention device for an injection molding machine, which is provided with a nozzle hole closing member that is freely and movable in a direction intersecting the axis of the nozzle and that can be brought into close contact with the nozzle.