JPS60210417A - Molding equipment - Google Patents

Abstract

PURPOSE:To contrive miniaturization of a device while dispersion in measurements of an injection-molded article is being controlled, by a method wherein a groove connecting a hole and an inner space of a first cylinder is formed on a mating face between a first and second cylinders and a nozzle hole other than the hole is provided further on the second cylinder. CONSTITUTION:Resin melted beforehand through a device melting the resin is led to a hole 33 by passing through a through hole 30, pushing a sphere 34 and passing through a clearance between a tapered hole 31 and the sphere and flows into an annular groove 40. As the annular groove 40 is wider than a spiral groove 39 a flowing rate of the molten resin in the annular groove 40 becomes larger than that in the spiral groove, therefore, the molten resin flows evenly through the eight spiral grooves 39. The molten resin passing through the spiral grooves 39 and exchanging heat with a first and second cylinders at places close to a heater 35, the temperature of which is made into even one, is led to a space 44 in the inside of the first cylinder 24 by passing through a through groove 41 and the space 44 is filled with the molten resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of Industry-12 2 Pesos The present invention relates to an apparatus used for resin molding.

Conventional Structures and Problems There has been a shift in production trends in recent years from mass production to instant production of a wide variety of products, and the demands on production equipment have changed accordingly. The same is true for injection molding machines, which are used in a particularly large number of plastic molding machines.In particular, miniaturization and cost reduction of mechanical equipment and creation of conditions that allow molding machines to be directly connected to assembly lines will improve space productivity and reduce production in small lots. This is required in order to obtain benefits such as improving cost and reducing process inventory.

However, the conventional injection molding machine has a plasticizing/injection mechanism using one type of in-line screw, and has a point that it does not meet the above requirements.

FIG. 1 is a cross-sectional view showing the main parts of the plasticizing/injection mechanism of a conventional injection molding machine.The rotation of the screw 2, which is rotatably and slidably fitted inside the cylinder 1, causes the material hopper 3 to The resin material stored in the interior 4 of the screw 2 is guided forward of the screw 2 by the groove 5 of the screw 2.

At this time, the resin is plasticized and melted by the heat transfer from the heater 6 of the cylinder 1 and the shearing action caused by the rotation of the screw 2 driven by the drive device 12. The plasticized resin is stored in the space 11 in front of the screw 2,
The rotation of screw 2 is stopped when the predetermined area is accumulated.
, After that, the sprue 9 of the mold consisting of the fixed mold 7 and the movable mold 8. In order to inject the molten resin into the cavity 10, the screw 2 is driven forward by the drive device 12. -1- An electric motor or a hydraulic motor is used as the screw 20 rotation means, a hydraulic cylinder is used as the injection means,
Both are generally provided at the rear of the screw 2.

The problems with the configuration described above are 1. The length of the screw becomes longer, making the entire device larger. 2. When changing the material, the previous 1" l existing in the screw groove is replaced with a new one. It is not easy to replace the material and it takes time to work. 3. The screw surface is wide, so the shearing force associated with rotation and injection is large.
For example, the output of the drive system necessarily needs to be thick.

Various attempts have been made to solve the above problems. Second
The figure shows one of them, and while the system shown in Figure 1 is called an in-line screw set, it is called a plunger set, and has a torpedo 14 inside the cylinder 13.
The whole is kept heated by the heater 15, and the material supplied from the material hopper 17 into the space 18 of the cylinder is pushed toward the torpedo 14 by the plunger 16, and the material is separated between the cylinder 13 and the torpedo 14. When passing through the space, the material is injected from the nozzle hole 20 while being plasticized and melted by heat transfer and shear heat. Japanese Utility Model Publication No. 54-45421 further proposes a rod in which a screw groove is formed at the tip of the plunger.

Although the single plunger type described above can solve some of the shortcomings of the one-sided inline screw type, such as the overall length and material switching, the operation of plasticizing and melting the material and injecting the material is done at the same time, and in principle it is difficult to plan. Since the work of the jar (ie, the product of the plunger driving force and the travel distance) is divided into the energy of plasticizing melting and the work of injection, the repeatability of the injection process is reduced as a result. The real problem caused by this is that the size variation in the molded product dimensions increases.

OBJECTS OF THE INVENTION An object of the present invention is to provide an injection device that reduces the size of the device while suppressing variations in the dimensions of injection molded products.

An injection device comprising a means for storing constituent resin of the invention and a means for injecting the stored resin, the means for storing the molten resin comprising a piston, a first cylinder, and a second cylinder. the piston is slidably fitted in the first cylinder in the axial direction, the 6-beb first cylinder is fitted and fixed inside the second cylinder, and the second cylinder is supplied with a gas supplied from the melting means. A hole is provided to receive the molten resin contained in the first cylinder, a groove is formed in the mating surface of the first cylinder and the second cylinder to connect the hole and the inner space of the first cylinder, and a groove is formed in the mating surface of the first cylinder and the second cylinder, and The cylinder is constructed by providing a nozzle hole in addition to the above-mentioned hole, and has the effect of eliminating unevenness in the temperature of the molten resin by using the wall surface of the cylinder.

DESCRIPTION OF EMBODIMENTS The present invention will now be described by way of embodiments. FIG. 3 is a cross-sectional view of an injection device according to an embodiment of the present invention, in which the tip 22 of the heating cylinder 21, which is part of the means for melting the resin in advance, is threaded to store the molten resin. It is connected to a second cylinder 23 which forms part of the means. A first cylinder 24 is fitted and fixed inside the second cylinder, and a piston 25 is fitted inside the first cylinder so as to be slidable in the axial direction. Said piston 25. First cylinder 24. The second (7) cylinder basically consists of a means for storing molten resin. A piston rod 26 that operates on an extension of the axis of the piston 25 and a drive cylinder 27 constitute an injection means.

FIG. 4 is a sectional view mainly showing the means for storing the molten resin shown in FIG. 3 in detail. A 1-peed 28 is provided inside the heating cylinder 21 which is a part of the means for melting the resin in advance, and a hole 28 is provided at the tip 22 of the heating cylinder 21 to communicate with a gap 29 between the heating cylinder 21 and the torpedo 28. A hole 30 is provided, and a tapered hole 31 in which the through hole widens into a tapered shape is further provided beyond the hole 30. A fiber screw provided at the tip 22 of the heating cylinder 21 is screwed and fixed to the 11111 screw 32 of the second cylinder 23. The hole 33 provided in the second cylinder 23 communicates with the through hole 30;
A sphere 34 is held in a floating state inside. Second
The cylinder 23 is provided with a plurality of heaters 35 and thermocouples (not shown), and furthermore, a spherical nozzle tip 37 is provided at the tip of a tapered protruding portion 36, and a nozzle hole 38 is provided. It has a perforation in its center. Second
A first cylinder 24 is fitted and fixed inside the cylinder 23 . A helical groove 39 and a ring-shaped groove 40 are provided on the outer periphery of the first cylinder, and a through groove 41 communicating with the helical groove 39 is provided at the bottom.

FIG. 6 shows an expanded view of the first cylinder, in which a ring-shaped groove 4° is provided so as to pass through the hole 33.
Eight helical grooves 39, which are thinner than the ring-shaped grooves, are provided toward the bottom from the ring-shaped groove 40, and a through groove 41 is provided at the bottom. The part indicated by the broken line is the second cylinder 23
It shows the position of the heating cylinder 35 provided in the. Returning to FIG. 4 and continuing the explanation, a piston 25 is fitted inside the first cylinder 24 so as to be slidable in the axial direction, and the piston is also provided with a heater 42 and a thermocouple 43.

In the above configuration, the resin melted in advance by the resin melting means passes through the through hole 30, pushes the sphere 34, passes through the clearance between the tapered hole 31 and the sphere 34, is guided into the hole 33, and flows into the ring groove 40. Ring-shaped groove 40C
Since the resin is wider than the helical grooves 39, a larger proportion of the molten resin flows into the ring-shaped grooves 40 than into the helical grooves near the holes 33, so that the molten resin flows almost equally into the eight helical grooves 39. The molten resin passing through the helical groove 39 exchanges heat with the first and second cylinders near the heating heater 35, becomes uniform in temperature, and passes through the passage groove 41 into the space inside the first cylinder 24. 44 is filled without being led. At this time, when the tip of the nozzle hole 38 is filled with the resin filled in the mold as in the case of normal injection molding measurement, the space 44 inside the first cylinder 24 is filled with the resin. The molten resin pushes against the piston 26.

By controlling the amount of movement of this piston 25, the first
It is possible to adjust the amount of resin filled into the internal space 44 of the cylinder. The resin stored in the space 44 applies pressure to the space 46 of the drive cylinder 27, so that the piston rod 26 is energized and the piston 26
is pressed, and the pressure of the resin in the space 441o increases. At this moment, a groove formed in the mating surfaces of the first cylinder 24 and the second cylinder, that is, a passage groove 41. Spiral groove 39. The resin under high pressure passes through the ring-shaped groove 40 and comes out of the hole 33, and acts on the sphere 34.
, the sphere 34 is pressed against the tapered surface of the tapered hole 31, and the resin cannot flow back toward the through hole 3o, so the nozzle hole 3
It is ejected from 8.

According to the above configuration, it is possible to equalize the temperature of the melted resin while passing through the grooves in the mating surfaces of the first cylinder 24 and the second cylinder 23, as shown in FIG. Even if a melting means that is difficult to melt to a uniform temperature is used, good molding is possible, and therefore the contradiction between miniaturization of the device and molded product quality can be resolved.

Another advantage of configuration 1 is that the injection energy applied by the injection means can be transferred to the injection of the molten resin without loss, and as a result, (combined with the ability to make the temperature of the resin uniform) ) The ability to manufacture molded products with extremely accurate dimensions.

In other words, in the in-line screw type as shown in Fig. 1, the resin between the screw and the cylinder exists over a wide area, and a considerable amount of screw driving energy is consumed at the time of injection. There are variations depending on the Uchiko. In the one-type plunger shown in FIG. 2, melting and injection of the resin are performed at the same time, making it difficult to achieve the more stable molding of the present invention.

FIG. 6 is a sectional view showing a means for melting the resin in advance, which is not applicable to the present invention. A nozzle hole 48 is provided at the tip, a fidget heater 4.9.60 is provided in the heating cylinder 46 and 1-peed 47, and an opening 51.1 of the heating cylinder is provided.
: Supply rod-shaped A1 fat material 62, 1-peed 47
The molten resin passes through the gap 63 between the torpedo 47 and the heating cylinder and into the nozzle hole 48.
It is something that can flow out more easily. The above means further allows the device to be made smaller.

As the means for melting the resin in advance and the means for injecting the molten resin in the present invention, any method used in ordinary injection molding machines can be adopted, and there is no need to particularly limit the method.

Effect of the invention As described above, the present invention has the following effects.

1. Since the wall surface of the cylinder can be used to eliminate unevenness in the temperature of the molten resin, molded products of long-lasting quality can be obtained.

2. Due to the above effects, it becomes possible to use a means of preliminarily melting the resin with a simple structure, thereby reducing the size and cost of the apparatus.

3. Since the energy from the injection means can be transmitted to the molten resin without loss, the injection conditions are stable and a large amount of injection energy can be taken, so the dimensional accuracy of the molded product can be improved.

[Brief explanation of the drawing]

1 and 2 are sectional views showing a conventional injection device, FIG. 3 is a sectional view of an injection device according to an embodiment of the present invention, and FIG. 4 is an enlarged sectional view of main parts of FIG. FIG. 6 is a developed view of the first cylinder, and FIG. 6 is a cross-sectional view showing a means for melting the resin in advance that can be applied to the present invention. 21... Heating cylinder, 24... First cylinder, 23... Second cylinder, 2
5... Piston, 33... Hole, 39.
... spiral groove, "... ring-shaped groove, 41.
...Gutter, 44...Space, 38...
... Nozzle hole, 27 ... Drive cylinder ゛-226
...Piston rod. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] An injection device comprising: a means for plasticizing and melting resin in advance, a means for storing the resin melted by the melting means, and a means for injecting the stored resin. means comprising a piston, a first cylinder, and a second cylinder, the piston being axially slidably fitted to the first cylinder, and the first cylinder being fitted within the second cylinder; The second cylinder is provided with a hole for receiving the molten resin sent from the melting means, and the hole and the inside of the first cylinder are provided on the mating surface of the first cylinder and the second cylinder. An injection device in which a groove connecting the spaces is formed, and a second cylinder is further provided with a nozzle hole in addition to the hole.