JPH066899Y2 - Injection molding nozzle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied to a two-material injection molding apparatus for injection-molding a laminated molded product of two or more colors of synthetic resin raw materials.
The present invention relates to a nozzle for material injection molding.

(Prior Art) Conventionally, in the method for obtaining a laminated product by injection molding, two kinds of resin raw materials as shown in FIG. 11 or FIG. 12 are plasticized and melted in separate heating cylinders 1 and 2, respectively. In the case of using an injection molding device in which a passage is formed so that the molten resin merges at the injection port via a switching valve 4 provided in front of one nozzle 3, or as shown in FIGS. 13 and 14. An inner cylinder nozzle 3'having a needle opening and closing type nozzle structure in which the injection port of the tip is opened and closed by a needle valve, and the inner cylinder nozzle 3'moves in and out of the outer cylinder nozzle 3 and is provided in the outer cylinder nozzle 3. The outer surface of the front end portion of the inner cylinder nozzle 3 ′ comes into contact with and separates from the valve seat formed so as to form a valve mechanism, and each molten resin passage can be kept isolated until just before the outer cylinder nozzle injection port 5, and A two-material injection molding machine with freely selectable valve opening / closing operation is used. .

(Problems to be Solved by the Invention) Among the above-mentioned conventional devices, the devices shown in FIGS. 11 and 12 have the advantage that the respective resins can be alternately injected by switching the switching valve 4 and the mechanism is simple. However, both resins cannot be injected at the same time, and a hesitation mark is generated when the flow of the resin is temporarily interrupted. In addition, the length of the resin passage from the switching valve 4 to the injection port 5 must be provided in a considerable amount due to the structure of the nozzle 3, and it is difficult to completely avoid color mixing during molding, and further, the shape of the molded product. There is a limit.

On the other hand, in the device shown in FIG. 13 and FIG.
Although the above-mentioned drawbacks of the apparatus shown in FIG. 12 and FIG. 12 are improved, the opening / closing mechanism of the outer cylinder nozzle 3 is operated by operating the inner cylinder nozzle 3'which is a needle opening / closing nozzle mechanism by some kind of power source. Since it has a double needle opening / closing nozzle structure, the mechanism becomes complicated and the sliding surface 6 of the needle valve in the inner cylinder nozzle and the sliding surface 7 for the inner cylinder nozzle to open and close. Since the resin easily leaks from the two sliding surfaces and the sliding portion is easily scratched, this is a cause of defective opening / closing operation.

Therefore, according to the present invention, the outer cylinder nozzle, the inner cylinder nozzle, and the needle valve are concentrically arranged at a predetermined interval, and are made of two colors or two or more kinds of synthetic resin raw materials. In an injection molding nozzle applied to a two-material injection molding apparatus for obtaining a molded product, the relative positions of both nozzles are fixed, and the needle valve has a small diameter portion smaller than the injection diameter of the inner cylinder nozzle and a large diameter equal to the same diameter. The needle valve is configured to be operated in two stages in forward and backward movements by appropriate drive means while being constituted by a diameter portion, which serves as means for solving the above problems.

(Function) This is a non-defective product that does not affect the next molded product by injecting the surface layer resin earlier than the core resin even if there is a slight time lag, and injecting the surface layer resin again at the end of injection. Since it is known that a molded product can be made, by using one needle valve as a sliding member and operating it in two stages, the tip of the needle valve is pushed or released to the inner surface of the tip injection port of the outer cylinder nozzle. , The surface side resin passage is opened and closed, the diameter of the injection port of the inner cylinder nozzle fitted and fixed to the outer cylinder nozzle is made the same as the outer diameter part of the needle valve, and the injection port of the inner valve is The core portion side resin passage is opened and closed by inserting or removing the outer diameter portion corresponding thereto. As a result, it is possible to open and close the surface-side resin passage and the core-side resin passage in sequence with appropriate timing, and since the sliding member is a single needle valve, resin leakage and needle valve operation failure Does not cause problems such as

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a plan view showing the appearance of a two-material injection molding nozzle of the present invention, and FIGS. 2 to 7 explain the structure and operation of a two-material injection molding nozzle that is a typical embodiment of the present invention. 8 to 10 are views for explaining the operation of another embodiment of the present invention.

First, in FIG. 1 and FIG. 2, A is the first injection unit, B is the second injection unit, and the first injection unit A
Is designed to plasticize, melt, and inject the resin for the surface layer of the laminated molded product, and the second injection unit B for the resin for the concentric portion, and the heating cylinders 8 and 9 are for the surface layer. A connecting plate 12 provided with a resin passage 10 and a core resin passage 11
Is stuck.

Contrary to the illustrated embodiment, the first injection unit A is used for molding the core resin, and the second injection unit B is used for molding the surface resin, as shown in FIG. This can be easily handled by changing a part of each of the resin passages 10 and 11 provided.

A valve body 17 is fixed to the opposite side of the connecting plate 12 from the cylinder. A connecting plate is provided at the joint between the connecting plate 12 and the valve body 17.
A distributor 18 for individually distributing and communicating the resin passages provided in 12 with the resin passages provided in the valve body 17 is fitted.

FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2, and clearly shows a state in which the resin passage 11 communicates with the distributor 18 from the valve body 17 to the inside of the inner cylinder nozzle 15. The inner cylinder nozzle 15 having a needle opening / closing mechanism and having an injection port 14 machined into a hole diameter that allows the core resin passage 11 to be blocked by fitting with the large diameter portion D of the needle valve 13 is a valve body.
It is sandwiched and fixed between 17 and the outer cylinder nozzle 16. The outer cylinder nozzle 16 is provided with a valve seat that blocks the surface layer resin passage 10 by pressing the needle valve 13, and is fixed to the valve body 17. The needle valve 13 is pressed against the injection port 21 of the outer cylinder nozzle 15 by an external drive source (hydraulic cylinder 20 in the illustrated example) capable of producing two-stage strokes via the drive plate 19, and at the same time the inner cylinder nozzle 15 is pressed. It is possible to block the two resin passages at the same time by fitting it into the injection port 14 of FIG. 2 and FIG. 2 shows the blocked state.

FIG. 4 shows that the external drive source capable of producing two strokes is operated only by the stroke amount of the first stage, and the needle valve 13 corresponds to the stroke amount of the first stage via the drive plate 19. By retracting by the stroke amount, the outer cylinder nozzle
The surface layer resin passage 10 formed between the inner surface of the inner cylinder 16 and the outer surface of the inner cylinder nozzle 15 is shown to be open in communication with the injection port 21 of the outer cylinder nozzle 16. The passage 11 is in a closed state because the large diameter portion D of the needle valve 13 is still fitted to the injection port 14 of the inner cylinder nozzle 15.

Fig. 5 shows an enlarged view of the tip of the nozzle in Fig. 4.
The step position and the step shape of the large diameter portion D and the small diameter portion d of 13 are flush with the position and shape of the injection port 14 of the inner cylinder nozzle 15,
Eliminates unnecessary resin retention.

FIG. 6 shows that, in addition to the first stroke shown in FIG. 4, the second stroke is operated to move the needle valve 13 to the most retracted position, and the surface resin passage 10 and the core resin passage 12 are moved. Shows the state where both are open.

Fig. 7 shows an enlarged view of the tip of the nozzle in Fig. 5.
The large diameter portion D of 13 is disengaged from the injection port 14 of the inner cylinder nozzle 15, and the gap of the difference between the large diameter portion D and the small diameter portion d is secured in the portion of the injection port 14 as the core resin passage 12. Become. In the case of injecting only the core resin in the state shown in FIGS. 5 and 7, for example, if the injection speed is lowered while maintaining the injection pressure in the injection conditions for the surface layer resin, only the core resin is injected. Injection is possible. Further, FIGS. 8, 9, and 10 show the positional relationship of the needle valve 13 corresponding to each of the above operations when the needle valve 13 has a straight shape without steps.

(Effect of the Invention) The two-material injection molding nozzle of the present invention is configured as described above,
By using a valve mechanism for each injection port of the inner and outer cylinder nozzles with a single needle valve, the advantages of molding when injecting two materials with the conventional double needle opening / closing nozzle structure are utilized. By eliminating the cause of malfunction of the sliding part due to resin leakage, galling, etc., its practical effect is extremely large.Furthermore, if the needle valve opening / closing operation and injection conditions are made appropriate, The molding conditions for efficiently obtaining various molded products can be easily dealt with.

[Brief description of drawings]

FIG. 1 is a plan view showing the appearance of a two-material injection molding apparatus to which the injection molding nozzle of the present invention is applied, and FIG. 2 is an enlarged sectional view of an injection molding nozzle showing a typical embodiment of the present invention. FIG. 3 is a sectional view taken along the line III-III in FIG. 2, and FIGS. 4 to 7 are sectional views showing an operating state of a needle valve which is a component of the present invention and a partially enlarged view thereof, and FIGS. FIG. 10 is a sectional view showing an operating state of a needle valve according to another embodiment of the present invention, and FIGS. 11 to 14 are schematic views of a conventional two-material injection molding apparatus equipped with injection molding nozzles of different types. FIG. Description of main parts of the figure 13 …… Needle valve, 15 …… Inner cylinder nozzle 16 …… Outer cylinder nozzle, 20 …… External drive source

Claims (1)

[Scope of utility model registration request] 1. A two-material injection molding apparatus in which an outer cylinder nozzle, an inner cylinder nozzle and a needle valve are concentrically arranged at a predetermined interval and a molded product is obtained from two colors or two or more kinds of synthetic resin raw materials. In the injection molding nozzle to be applied, the relative positions of the two nozzles are fixed, and the needle valve is composed of a small diameter portion smaller than the injection opening diameter of the inner cylinder nozzle and a large diameter portion equal to the same diameter, and the needle is the same. An injection molding nozzle characterized in that a valve is appropriately operated in two stages in forward and backward movements by a driving means.