JPS5928453B2 - Injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultra-compact injection molding machine, which includes an injection cylinder 1 and a measuring cylinder 2 that are coaxially arranged, and an injection cylinder that is internally movable reciprocally within the measuring cylinder 2 and has an injection cylinder 1 and a measuring cylinder 2 arranged coaxially. a hollow pipe-shaped metering plunger 5 for supplying the resin in the metering cylinder chamber 3 to the injection cylinder chamber 4 in the injection cylinder 1; The specified invention is an injection molding machine consisting of an injection plunger 6 for injecting , an injection cylinder 1 and a measuring cylinder 2 coaxially arranged, and a measuring cylinder 2 which is internally movable reciprocally within the measuring cylinder 2.
A metering plunger 5 for supplying the resin in the metering cylinder chamber 3 inside the injection cylinder chamber 4 to the injection cylinder chamber 4 inside the injection cylinder 1; An injection device comprising an injection plunger 6, a first torpedo 7 provided between the metering cylinder chamber 3 and the injection cylinder chamber 4, and a second torpedo 8 provided at the front of the injection cylinder chamber 4. This invention relates to a molding machine as a merged invention.

There has been a demand for smaller molding machines for some time, but this has been difficult due to the strength of the molding machines.

In particular, for small parts such as gears, cams, and levers, molding machines with reciprocating screws are generally used to improve the agitation of the molding material. There was a problem.

Furthermore, even though plunger type molding machines are stronger than screw type molding machines, if the product weight is less than 11, there is a problem with the diameter of the plunger used to inject the product, and furthermore, it has the disadvantage that stirring and kneading cannot be performed. Ta.

Moreover, the conventional plunger type molding machine has a measuring cylinder 2' intersecting the injection cylinder 1' at an arbitrary angle as shown in FIG. ', and a metering plunger 5' were respectively inserted therein.

This has the disadvantage that the outer dimensions of the injection cylinder 1' and the metering cylinder 2' are large, and furthermore, when the injection plunger 6' is pushed, the material flows back toward the metering cylinder 2', so a check valve is required. There was a drawback.

The present invention has been made in view of the above points, and the object of the present invention is to provide an injection cylinder, a metering cylinder,
Since the metering plunger and injection plunger are coaxially arranged, the external size can be reduced.

In addition, the injection plunger is inserted through the metering plunger, and the injection plunger is guided by the metering plunger, so even if the injection plunger is thin, it is strong and can perform high-pressure, low-weight injection, and the resin can be injected with the plunger. No. 1 even if you do it. Good stirring and kneading is done in the second torpedo,
The purpose of the present invention is to provide an injection molding machine that can mold uniform products.

The present invention will be explained in detail below with reference to Examples.

9 is a main body cylinder, and a hopper 10 is attached above the tip.

Two male threaded rods 12 are rotatably installed on the instrument stand 11, and the male threaded rods 12 are screwed into the lower part of the main body cylinder 9.

A sprocket 13 is attached to each end of the male threaded rod 12, and a chain 14 is placed between the sprockets 13. By rotating a sprocket 15 disposed between the sprockets 13, the chain 14 and the sprocket 1 are rotated.
3, the male threaded rod 12 is rotated, and the main body cylinder 9 can be reciprocated.

A measuring cylinder 2 is mounted inside the main body cylinder 9 on the front side, and the inside of the hopper 10 and the inside of the measuring cylinder 2 are communicated through a drop port 16.

Here, 17 is an opening/closing plate that opens and closes the supply port between the hopper 10 and the drop port 16.

The injection cylinder 1 consists of a front cylinder block 1a, a middle cylinder block 1b, and a base cylinder block 1c.
The injection cylinder 1 is formed by screwing together two blocks.
The injection cylinder 1 and the metering cylinder 2 are coaxially connected by screwing the male threaded portion 18 at the base end of the injection cylinder 1 to the male threaded portion 19 at the tip of the metering cylinder 2.

A hollow pipe-shaped metering plunger 5 with a pointed tip is inserted into the metering cylinder 2 so as to be able to reciprocate, and an injection plunger 6 with a pointed tip is inserted into the metering plunger 5 so that it can be reciprocated. .

The space between the metering cylinder 2 and the injection plunger 6 is a metering cylinder chamber 3, and the inside of the injection cylinder 1 is an injection cylinder chamber 4.

A heater 29 is provided around the outer periphery of the injection cylinder 1.

A first torpedo 7 is provided between the metering cylinder chamber 3 and the injection cylinder chamber 4, and a constricted portion 20 with a narrow gap is provided at the tip of the first torpedo 7.

A second torpedo 8 is provided at the front of the injection cylinder chamber 4, and the tip of the second torpedo 8 serves as a nozzle port 21.

The second torpedo 8 may have the shape shown in FIG. 4 or the shape shown in FIG. 5.

A lid 21 is screwed onto the base end of the main body cylinder 9, and a metering drive cylinder chamber 22 and an injection drive cylinder chamber 23 are provided inside the main body cylinder 9.

A piston 24 that is reciprocated by hydraulic pressure is housed in the metering 1 drive cylinder chamber 22, and the base end of the metering plunger 5 is connected to the piston 24. By driving the piston 24 once, the metering plunger 5 is moved. can be driven in one reciprocating manner.

The injection drive cylinder chamber 23 is equipped with a piston 25 that is reciprocated by hydraulic pressure, and a relay shaft 26 whose one end is connected to the injection plunger 6 is connected to the piston 25. By driving the piston 25, injection can be performed. The plunger 6 is designed to be driven back and forth.

The other end of the relay shaft 26 protrudes from the lid 27, and a stroke adjustment nut 28 is screwed onto this protrusion.

Next, the operation of the injection molding machine configured as described above will be explained.

When the resin pellets are supplied to the hopper 10 and the opening/closing plate 17 is opened, the resin pellets are supplied to the drop port 16.

At this time, the resin is melted by a heater installed in the main body cylinder 9.

To inject, first pull the injection plunger 6 to position the tip at the mouth position shown in Figure 3, then push the calculation plunger 5 so that the tip moves from the second position to the second position to the metering cylinder chamber 3. The molten resin inside the first torpedo 7
A fixed amount of molten resin is fed into the injection cylinder chamber 4 through Nozzle port 21 via torpedo 8
eject from.

This cycle is repeated to inject a fixed amount of molten resin from the nozzle port 21.

When the metering plunger 5 is pushed to supply resin into the injection cylinder chamber 3, since the resin is molten, an accurately measured amount of resin is supplied.

Further, when the injection plunger 6 is pushed to inject the molten resin, the resin does not flow backwards because there is a constriction part 20 at the tip of the first torpedo 1.

Further, since there are the first torpedo 7 and the second torpedo 8, the resin is uniformly stirred and kneaded.

In addition, the molten resin injected from the nozzle port 21 is filled into the cavity in the molding die and molded. In the present invention, as described above, the injection cylinder, metering cylinder, metering plunger, and injection plunger are arranged coaxially. , it can be miniaturized by having a smaller external size than conventional ones, and since the injection plunger is inserted through the hollow pipe-shaped metering plunger, the injection plunger is guided by the metering plunger, and the injection plunger is thin. However, it is strong in terms of strength and can be injected at high pressure and with a small weight (up to about 0.1 g).

In addition, in the merged invention of the present invention, the first torpedo and the second torpedo
Since it has a torpedo, it has the advantage that even if it is injected with a plunger, it can be stirred and kneaded uniformly by both torpedoes, and a uniform product can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of a conventional example, Fig. 2a is a sectional view of an embodiment of the present invention, Fig. 2 is a side view of Fig. 2a, and Fig. 3 is an enlarged view of the same injection cylinder section. 4 is a sectional view of the same injection cylinder as above, and FIG. 5 is a sectional view of another embodiment of FIG. 4, in which 1 is an injection cylinder, 2 is a metering cylinder,
3 is a metering cylinder chamber, 4 is an injection cylinder chamber, 5 is a metering plunger, 6 is an injection plunger, 7 is a first torpedo,
8 is the second torpedo.

Claims (1)

[Scope of Claims] 1. An injection cylinder and a metering cylinder arranged coaxially, and a metering cylinder that is internally movable in a reciprocating manner and transfers resin in a metering cylinder chamber in the metering cylinder to an injection cylinder chamber in the injection cylinder. An injection molding machine comprising a hollow pipe-shaped metering plunger for supplying resin, and an injection plunger that is inserted into the metering plunger so as to be able to reciprocate and inject resin in an injection cylinder chamber. 2. The injection molding machine according to claim 1, characterized in that a constricted portion with a narrow gap is provided between the metering cylinder chamber and the injection cylinder chamber. 3. An injection cylinder and a metering cylinder arranged coaxially, and a metering plunger that is reciprocatably installed inside the metering cylinder and supplies the resin in the metering cylinder chamber in the metering cylinder to the injection cylinder chamber in the injection cylinder. an injection plunger that is reciprocably housed within the injection cylinder and injects the resin in the injection cylinder chamber; a first torpedo provided between the metering cylinder chamber and the injection cylinder chamber;
An injection molding machine comprising a second torpedo provided at the front of an injection cylinder chamber.