JP3131674B2 - Injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine for forming a plastic molded product by injecting a resin into a mold, and more particularly to an injection molding machine for forming a mixed pattern of different colors on a molded product.

[0002]

2. Description of the Related Art As shown in FIG. 9, a conventional multicolor molding machine includes a heating cylinder 50 for each color to be used and a single nozzle 51, and a shutoff provided between each heating cylinder 50 and the nozzle 51. The valve is opened and closed with a time lag by an off valve 52, and resins having different colors are alternately supplied to the nozzle 51 to obtain a molded product having a marble pattern.

[0003]

However, conventional multicolor molding machines have the following problems.

[0004] Since a heating cylinder and a resin injection mechanism for each color to be used are required, a molding machine becomes large, and it is costly to manufacture the molding machine.

Since the shut-off valve and the junction are interposed between the heating cylinder and the nozzle, it has been difficult to control the temperature of the resin.

[0006] Since resins of different colors are supplied to the nozzles by switching the shut-off valve, a clear and fine pattern cannot be formed, and the timing of switching the shut-off valve is difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to make it possible to easily and clearly form a pattern in which different colors are mixed in an injection molded article. is there.

[0008]

In order to solve the above problems, an injection molding machine according to the present invention comprises a heating cylinder having a supply means for a molding material, and a slidably inserted inside the heating cylinder. A plunger for feeding the material, and an injection head having a nozzle provided at the tip of the heating cylinder, and an impeller having a plurality of blades rotatably provided across a passage formed in the injection head. It is characterized by the following.

[0009] It is desirable to dispose the topedo in the above-mentioned heating cylinder so as to form a passage around it, and to dispose the top end thereof to face the rear end of the passage formed in the injection head.

[0010]

The resin in a state in which the master batch and the natural raw material are mixed is supplied to the heating cylinder, and the resin is sent out by the injection device. The resin is heated, and the colored portion becomes streaky and melts, moves between the torpedo and the heating cylinder, and is extruded from the cylinder head to the injection head, and the impeller provided in the injection head is moved by the fluid pressure. Rotate. At this time,
The blade formed at the tip of the blade of the impeller divides the resin in which the colored portion becomes streaked, and disturbs the flow. The resin in which the streaky colored portions are separated is mixed when passing through the nozzle filter to form a clearer and finer pattern.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an injection molding machine according to the present invention will be described with reference to FIGS. The injection molding machine of the present invention is provided with an injection device for melting and injecting a molding material into a cavity formed by a mold that is opposed and clamped. Heating cylinder 1, a plunger 2 disposed behind the heating cylinder 1 for injecting a molten molding material, and a hopper for supplying the molding material into the heating cylinder 1.
3 and topid 4 arranged in heating cylinder 1 and heating cylinder 1
, And an injection head 5 for guiding the molten molding material to a mold, and an impeller 6 is rotatably provided in the injection head 5.

The heating cylinder 1 has a heater 11 on the outer peripheral wall of the cylinder 10.
A plunger 2 connected to a driving device (not shown) such as a hydraulic cylinder is slidably provided at the rear end of the plunger 2. A hopper 3 is provided at the bottom. A first cylinder head 12 and a second cylinder head 13 are attached to the front end of the cylinder 10 by bolts 14. A through hole 15 is provided between the first cylinder head 12 and the second cylinder head 13, and the through hole of the first cylinder head 12 is provided.
Reference numeral 15 denotes a tapered shape that continuously decreases in diameter from the cylinder toward the front, and a female screw 16 is provided at an enlarged diameter portion located at the tip thereof.
5 is screwed.

The torpedo 4 has a rear tapered portion 4a which continuously decreases in diameter toward the plunger 2 and a front tapered portion 4b which reduces in diameter toward the injection head 5 at the rear. The tapered portion 4b, the rear tapered portion 4a, and an intermediate portion thereof are provided with a ridge 18 to form a passage 19 while maintaining a predetermined interval between the tope 4 and the inner wall of the cylinder 10, and the resin is formed on the inner wall of the cylinder 10. And uniformly heat and melt. Ridge 18
Have a shape that does not hinder the flow of the resin, and are formed at equal intervals so as to be parallel to the longitudinal direction of the tope.
In this embodiment, the shape of the tip of the torpedo is shown in FIG.
As shown in FIG. 4, it is formed in a tapered shape whose diameter is reduced toward the front. However, as shown in FIG. 4, it is formed in a hemispherical shape, or as shown in FIG. May be alternately arranged. When the tip shape shown in FIG. 4 is hemispherical, the mixing effect is greater than that of the tapered shape shown in FIG.
In the case where the ridges shown in FIG. 4 are alternately arranged, the mixing effect is larger than that shown in FIG.

As shown in FIG. 2, the injection head 5 includes a passage 20 having a diameter reduced toward the front, a passage 21 having an increased diameter following the passage 20, and a nozzle filter 23 and a nozzle located in the passage having an increased diameter. 24 are arranged continuously, and the impeller 6 provided across the reduced-diameter passage 20 is rotatably provided.
Since it is provided at the center of the front surface of the cylinder head 12, it is screwed to the screw 16.

The reduced diameter passage 20 is provided in the first cylinder head.
In the middle of this passage 20, a bearing 25, an impeller housing chamber 26, and a female thread 27 are formed in the direction perpendicular to the passage 20 continuously. Screw part 27
Is screwed with a bolt 29 having a bearing 28 formed at the tip (see FIG. 3). The impeller 6 has a plurality of blades
At the tip of the blade 31 in the rotation direction, a blade portion 32 is formed, and the radius from the center of the rotating shaft 30 to the tip of the blade 31 has substantially the same size as the diameter of the reduced passage 20. are doing.
The impeller 6 thus configured is disposed in the impeller accommodation chamber 26, and the rotating shaft 30 is pivotally supported by bearings 25 and 28,
The resin is extruded by the plunger 2 and is rotated by the fluid pressure of the resin. The resin is divided by a blade 32 formed at the tip in the rotational direction. By providing the impeller 6 in the reduced-diameter passage 20, the impeller 6 can be made small, and the resin is finely divided, so that a fine striped pattern is formed on the molded product. Can be.

The nozzle filter accommodating portion 35 is provided through a tapered portion that continuously increases in diameter from the passage 20 whose diameter is reduced.
A female screw portion 36 is formed, the spacer 37 and the nozzle filter 23 are inserted into the nozzle filter accommodating portion 35, the nozzle 24 is screwed into the female screw portion 36, and the nozzle filter 23 is fixed by the spacer 37 and the nozzle 24. I have. The inner diameter of the spacer 37 is set to be larger than the inner diameter of the passage 20 whose diameter is reduced, thereby forming the enlarged passage 21, and reducing the pressure loss of the resin sent out by the plunger 2. As shown in FIG. 6, the nozzle filter 23 is provided with a through hole 39 in a disc-shaped plate, and the resin is passed through the through hole 39 to mix the resin divided by the impeller 6. Give effect. As shown in FIGS. 7 and 8, the nozzle filter 23 having a plurality of through holes 40 and 41 can further enhance the mixing effect. Further, a spiral ridge may be provided on the inner wall surface of the spacer 37 instead of the through hole 39 of the nozzle filter 23.

The operation of the injection molding machine according to the present invention configured as described above will be described. The heater 11 of the heating cylinder 1 is heated to a temperature suitable for melting the molding material, the master batch as the molding material and the natural material are supplied from the hopper 3 in a mixed state, and the plunger 2 is moved forward. The molding material contacts the inner wall of the cylinder 10 evenly by the torpedo 4, is heated and melted, and is sent to the injection head 5 in a state where the colored portions are mixed in a streak shape. Reduced path of injection head 5
The impeller 6 provided at 20 is rotated by the flow pressure of the molten resin. At this time, the molten resin sent out is cut by the tip blade 32 of the blade 31 of the rotating impeller 6, and the laminar flow is disturbed. The resin that has been cut and disturbed in the laminar flow is further fed through the nozzle filter 23 of the passage 21 whose diameter has been increased and mixed, and is injected from the nozzle 24 into the mold to form an irregular concentric marble stripe pattern. Are clearly formed.

[0018]

As described above, according to the present invention, it is possible to form a clear pattern on a molded product with a simple structure in which an impeller is rotatably mounted in a passage between a torpedo and a nozzle. Can be played.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing one embodiment of an injection molding machine according to the present invention.

FIG. 2 is an enlarged sectional view of a front part of the injection molding machine.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a partial cross-sectional view showing a modified example of a front end of a topeed.

FIG. 5 is a partial cross-sectional view showing another modification of the front end of the topeed.

FIG. 6 is a front view of the nozzle filter.

FIG. 7 is a front view of another example of the nozzle filter.

FIG. 8 is a front view of still another example of the nozzle filter.

FIG. 9 is a schematic sectional view of a conventional injection molding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating cylinder 2 Plunger 3 Hopper 4 Topeed 5 Injection head 6 Impeller 20 Reduced diameter path 21 Expanded diameter path 23 Nozzle filter 24 Nozzle 31 Blade

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/16-45/17 B29C 45/53-45/54 B29C 45/58-45/62

Claims (2)

(57) [Claims] 1. A heating cylinder having means for supplying molding material,
It consists of a plunger slidably inserted into the inside of the heating cylinder, for sending out the molding material, and an injection head having a nozzle provided at the tip of the heating cylinder, and a plurality of injection heads traversing a passage formed in the injection head. An injection molding machine characterized in that an impeller having blades is rotatably provided. 2. The torpedo is arranged in the heating cylinder so as to form a passage around the top of the heating cylinder, and the tip of the topeed is arranged so as to face the rear end of the passage formed in the injection head. 2. The injection molding machine according to 1.