JPH0623805A - Hot runner mold - Google Patents

Abstract

PURPOSE:To prevent the occurrence of resin leakage and air contamination during the opening period of mold in a hot runner type stack mold. CONSTITUTION:An extension manifold main body 63 is secured to a main manifold 46. In the inner part of a fixation hole at the tip end of the extension manifold main body 63, a nozzle touch body 65 with a nozzle 6 connected thereto is slidably fitted in the mold opening and closing directions. The nozzle touch body 65 is urged toward the nozzle 6. A resin passage 72 within the extension manifold main body 63 is opened to the inner peripheral surface of a fixation hole 72. A resin passage 69 within the nozzle touch body 65 is also opened to the outer peripheral surface of the nozzle touch body 65. During the clamping period of mold, as the nozzle 6 is connected to the nozzle touch body 65, the nozzle touch body 65 drops into the extension manifold 63 with the result that the resin passages 69, 72 intercommunicate with each other. Also, during the opening period of mold, as the nozzle 6 separates from the nozzle touch body 65, the nozzle touch body 65 projects from the extension manifold main body 63 with the result that the resin passages 69, 72 are interrupted each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot runner mold used for a stack mold or the like, and more particularly to a resin passage opening / closing mechanism.

[0002]

2. Description of the Related Art A hot runner type stack molding die used in injection molding includes a fixed die and a movable die that sandwich an intermediate die and open and close with respect to the intermediate die. Also, the product is molded between the intermediate mold and the movable mold. The intermediate mold has a main manifold for distributing the resin supplied from the nozzle of the injection molding machine into cavities formed between the fixed mold and the intermediate mold and between the intermediate mold and the movable mold. While the intermediate plate including the main manifold opens and closes with respect to the fixed mold, in general, the position of the nozzle with respect to the fixed mold during molding is fixed, so with mold clamping and mold opening, The positional relationship between the nozzle and the main manifold changes. Therefore, in a normal stack molding die, the resin passage from the nozzle to the main manifold is connected and disconnected as the mold is clamped and opened. For example,
The extension manifold penetrating the fixed die is fixed to the main manifold, the nozzle of the injection molding machine is connected to the extension manifold when the die is clamped, and the nozzle is separated from the extension manifold when the die is opened. However, if the resin passage in the extension manifold is always open when the nozzle is separated from the extension manifold when the die is opened in this way, the nozzle of the extension manifold will be affected by the resin pressure in the manifold when the die is opened. Resin easily leaks from the touch part. If the resin leaks in this way, the leaked resin may be sandwiched between the mold and the nozzle at the next mold clamping, and the mold and the nozzle may be damaged. At the same time, air easily enters the resin passage of the extension manifold. When air enters in this way, there is a risk of defective molding such as pattern formation on the molded product.

Therefore, conventionally, a valve device for opening and closing the resin passage of the extension manifold has been provided, but the conventional valve device uses a hydraulic cylinder device or the like.
The structure is complicated.

[0004]

As described above, in the conventional stack-molding die, the extension manifold fixed to the main manifold provided in the intermediate die is usually injection-molded as the die is clamped and opened. Although the nozzle of the machine is attached and detached, if the resin passage of the extension manifold is always open, there is a problem that resin may leak or air may enter the resin passage when the mold is opened. Further, even in the case where the valve device that opens and closes the resin passage is provided, the conventional valve device uses a hydraulic cylinder device or the like, and there is a problem that the structure is complicated.

The present invention is intended to solve such a problem, and when the nozzle on the injection molding machine side is separated from the extension manifold, the resin is introduced from the resin passage of the extension manifold by the valve device having a simple structure. It is an object of the present invention to provide a hot runner mold that can prevent air leakage and air from entering the resin passage.

[0006]

In order to achieve the above-mentioned object, the present invention is provided in a plurality of mold bodies which open and close each other and which form a cavity inside during mold clamping, and one of these mold bodies. A main manifold and an extension manifold connected to the main manifold and having nozzles on the injection molding machine side detachably connected, the main manifold having a resin passage to the cavity, In a hot runner mold which has a resin passage inside which allows resin injected from the nozzle of the injection molding machine side to flow to the resin passage of the main manifold, and which always keeps the resin in the resin passage of these manifolds in a molten state. The extension manifold includes an extension manifold main body fixed to the main manifold, and a main manifold in the extension manifold main body. And a nozzle touch body to which the nozzle of the injection molding machine side is detachably connected and which is slidably fitted in the opening and closing direction of the mold body at the end opposite to the nozzle. The resin passage in the body is
It is a sliding surface between the extension manifold main body and the nozzle touch body, and when the nozzle touch body moves to the main manifold side, they overlap each other and when they move to the opposite side, they are opened to positions that separate from each other. The nozzle touch body is biased to the side opposite to the main manifold.

[0007]

In the hot runner mold of the present invention, a plurality of mold bodies are clamped at the time of molding, and the nozzle on the injection molding machine side is connected to the nozzle touch body of the extension manifold. At this time, the nozzle touch body is pushed by the nozzle and moves toward the main manifold side against the bias of the spring. Accordingly, the resin passage of the extension manifold main body and the resin passage of the nozzle touch body are communicated with each other such that the openings to the sliding surfaces of the extension manifold main body and the nozzle touch body overlap each other. In this state, the resin is injected from the nozzle into the resin passage of the nozzle touch body. This resin flows from the resin passage in the nozzle touch body through the resin passage in the extension manifold main body into the resin passage of the main manifold, From there, the cavities formed between the mold bodies are filled.
After the injection process and the pressure-holding process, the resin filled in the cavity is sufficiently cooled and solidified, and then a plurality of mold bodies are opened to solidify the resin in the cavity. Take out the molded product. By the way, for example, with mold opening,
When the nozzle on the injection molding machine side moves away from the nozzle touch body,
This nozzle touch body moves to the side opposite to the main manifold by the spring bias against the extension manifold body, and the resin passage of the extension manifold body and the resin passage in the nozzle touch body are separated from each other by the extension manifold body and the nozzle touch body. The openings to the sliding surfaces are offset from each other and are blocked from each other. Therefore, the resin does not easily leak from the resin passage of the extension manifold, and air does not enter the resin passage. Moreover, since a little resin hangs from the resin passage of the nozzle touch body to the outside, the entrainment of air during the subsequent connection of the nozzles is more reliably prevented. After the molded product is taken out, the mold is clamped again and the molding is repeated. Through such a molding cycle, the resin in the resin passage of the manifold is always kept in a molten state. The volume of each resin passage does not change with the opening and closing of the resin passage.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the hot runner mold of the present invention will be described below with reference to the drawings. The mold of this example is a stack mold as shown in FIGS. 1 and 5. First, the outline of the configuration of an injection molding machine to which this mold is attached will be described mainly based on FIG. Reference numeral 1 is a fixed platen, 2 is a tie bar, and 3 is a movable platen. The movable platen 3 is moved along the tie bar 2 by the driving of the mold clamping mechanism 4, and moves toward and away from the fixed platen 1. Further, 5 is a heating cylinder. A nozzle 6 is provided at the left end of the heating cylinder 5 in the drawing. A screw 7 (shown in FIG. 2) is provided in the heating cylinder 5. The screw 7 is rotationally driven as well as axially driven to knead, measure, inject, and hold the resin. A hopper 8 for putting a pallet of thermoplastic resin is provided on the heating cylinder 5.

The stack mold die includes a fixed die 11, an intermediate die 12 and a movable die as a plurality of die bodies that open and close each other.
It has 13 and. The fixed mold 11 is attached to the fixed platen 1 of the injection molding machine, and the movable mold 13
Is attached to the movable platen 2 and moves integrally with the movable platen 2. On the other hand, the intermediate type
The guide rod 14 is movably supported between the fixed die 11 and the movable die 13 by a guide rod 14, and is driven by the die clamping mechanism 4 via a coupling mechanism (not shown). In this way, the intermediate die 12 and the movable die 13 respectively move in the left-right direction in the drawing, so that the fixed die 11 opens and closes on the right side and the movable die 13 opens and closes on the left side with respect to the intermediate die 12. . Then, as shown in FIG. 1, during mold clamping, between the fixed mold 11 and the intermediate mold 12 and between the intermediate mold 12 and the movable mold.
A plurality of product-shaped cavities 15 and 16 are formed between the cavities 13 and 13.

As shown in FIG. 1, the fixed mold 11 includes a fixed side mounting plate 21 mounted on the fixed side platen 1 and a receiving plate fixed on the left side of the fixed side mounting plate 21 via a spacer block 22. 23 and a template 24 fixed to the left side of the receiving plate 23. Further, the fixed side mounting plate 21
A protruding plate 25 that moves in the left-right direction relative to these is provided between the receiving plate 23 and the receiving plate 23, and the protruding plate 25 is formed between the fixed mold 11 and the intermediate mold 12. An ejection pin 26 for releasing the formed product when the mold is opened is fixed. On the other hand, the movable mold 13 includes a movable side mounting plate 31 mounted on the movable side platen 3, a receiving plate 33 fixed to the right side of the fixed side mounting plate 31 via a spacer block 32, and the receiving plate 33. And a template 34 fixed to the right side. In addition, the movable side mounting plate 31 and the receiving plate 33
A protruding plate 35 that moves in the left-right direction relative to these is provided between and, and a molded product formed between the intermediate mold 12 and the movable mold 13 is provided on the protruding plate 35. The ejection pin 36 for releasing the mold when the mold is opened is fixed. Further, the intermediate mold 12 includes a pair of receiving plates 42 and 43 fixed to each other via a spacer block 41, a mold plate 44 fixed to the right side of the right receiving plate 42, and a left side of the left receiving plate 43. And a template 45 fixed to. Then, between the mold plate 24 of the fixed mold 11 and the right mold plate 44 of the intermediate mold 12, and between the mold plate 34 of the movable mold 13 and the left mold plate 45 of the intermediate mold 12, cavity 15, 16 are to be formed. Further, between the two receiving plates 42, 43 of the intermediate mold 12,
A main manifold 46 is provided. The main manifold 46 has therein a runner 47 as a resin passage for distributing the molten thermoplastic resin supplied from the nozzle 6 of the injection molding machine to the cavities 15 and 16, and
Built-in heater 48. Also, the main manifold
Bushings 49, 50 connected to both left and right sides of the support plate 42,
It penetrates through 43 and templates 44 and 45. These bush 4
9 and 50 have gates 51 and 52 at their tips that open into the cavities 15 and 16, respectively. That is, the final branch of the runner 47 of the main manifold 46 is
The cavities 15 and 16 are communicated with each other through the insides of 9 and 50. Further, valve pins 53 and 54 for opening and closing the gates 51 and 52 are built in the bushes 49 and 50. These valve pins 53 and 54 are connected to the main manifold 46.
And is driven by cylinder devices 55 and 56 embedded in the receiving plates 42 and 43 on the side opposite to the corresponding bushes 49 and 50.

An extension manifold 61 connected to the main manifold 46 passes through the fixed mold 11. The extension manifold 61 applies the molten resin injected from the nozzle 6 of the injection molding machine to the runner 47 of the main manifold 46.
The valve device 62 is provided at the tip opposite to the main manifold 46, that is, on the nozzle 6 side. Next, the configuration of the valve device 62 will be described with reference to FIGS.
Will be described. A fitting hole 64 that opens to the right end face is formed at the right end of the elongated extension manifold body 63 whose left end is fixed to the main manifold 46.
Nozzle touch body 65 is shown in the left-right direction in the figure 64
11 and the intermediate die 12 are slidably fitted in the opening / closing direction. The nozzle touch body 65 is an extension manifold body 63.
Has a flange portion 66 at the right end portion that abuts the right end surface of the. A coil-shaped spring 67 is provided between the flange portion 66 and the extension manifold main body 63, and the spring 67 allows the nozzle touch body 65 to move to the side opposite to the main manifold 46 with respect to the extension manifold main body 63. Always energized. The nozzle touch body 65 is the extension manifold body.
It is properly prevented from falling off against 63. On the other hand, the extension manifold main body 63 is formed with an air escape hole 68 that extends from the inner part of the left end of the fitting hole 64 to the outer peripheral surface. Further, in the nozzle touch body 65, the nozzle 6 of the injection molding machine is detachably connected to the right end face, but the resin passage 69 opening to the right end face is formed in the axial direction, that is, the left-right direction. . This resin passage 69 branches radially at the left end,
An outer peripheral surface 65a of the nozzle touch body 65, that is, a sliding surface with the extension manifold main body 63 is opened. More specifically, the outlet portion 70 of the resin passage 69 is located at a portion of the outer peripheral surface 65a of the nozzle touch body 65 that is always located in the fitting hole 64 of the extension manifold body 63. An annular groove 71 is formed on the outer peripheral surface of the nozzle touch body 65 through the plurality of outlet portions 70. On the other hand, a resin passage 72 is also formed in the extension manifold main body 63 in the axial direction, that is, the left-right direction. The left end of this resin passage 72 is the main manifold.
It leads to the entrance of 46 runners 47. On the other hand, resin passage
The right end portion of 72 is a branch portion 73 that branches around the outer circumference of the fitting hole 64 while branching. The tips of these branch portions 73 are
It is bent inward and opens to the inner peripheral surface 64a of the fitting hole 64, that is, the sliding surface with the nozzle touch body 65. More specifically, the inlet portion 74 of each branch portion 73 has the inner peripheral surface 64 of the fitting hole 64.
The nozzle touch body 65 in a is always located in the overlapping portion. The positional relationship between the outlet portion 70 of the resin passage 69 of the nozzle touch body 65 and the inlet portion 74 of the resin passage 72 of the extension manifold body 63 is as shown in FIG. The outlet portion 70 and the inlet portion 74 overlap each other when 65 is displaced to the right limit position, and the outlet portion 70 and the inlet portion 74 are set to be disengaged from each other when positioned further to the left. A band heater 75 is provided on the outer peripheral surface of the extension manifold 61. Further, as shown in FIG. 1, a locate ring 76 is fixed to the fixed side mounting plate 21 so as to surround the extension manifold 61.

Next, the operation of the above configuration will be described. As shown in Fig. 1, the fixed mold
The intermediate die 12 is clamped to 11 and the intermediate die 12
The movable mold 13 is clamped against the cavities between the fixed mold 11 and the intermediate mold 12 and between the intermediate mold 12 and the movable mold 13, respectively.
Form 15 and 16. With the mold clamping between the fixed mold 11 and the intermediate mold 12, as shown in FIGS. 1 and 2, the nozzle 6 of the injection molding machine is connected to the nozzle touch body 65 of the extension manifold 61, and the nozzle touch body 65 is also connected. Push to the left, ie towards the main manifold 46. In response to the force, the nozzle touch body 65 moves leftward with respect to the extension manifold main body 63 against the bias of the spring 67 until the flange portion 66 contacts the right end surface of the extension manifold main body 63. In this state, the inlet portion 74 of the resin passage 72 of the extension manifold main body 63 and the annular groove 71 that penetrates the outlet portion 70 of the resin passage 69 of the nozzle touch body 65 overlap each other, and the resin passage 72 of the extension manifold main body 63 and the nozzle. The resin passage 69 of the touch body 65 communicates with each other. When the nozzle touch body 65 sunk into the fitting hole 64 of the extension manifold main body 63, the air in the fitting hole 64 escapes to the outside through the air escape hole 68.

In the injection molding machine, the thermoplastic resin P supplied from the hopper 8 into the heating cylinder 5 is melted by heating and the rotation of the screw 7, and when the screw 7 is retracted, the tip of the inside of the heating cylinder 5 is melted. A predetermined amount is collected in the section. In the mold clamping state as described above, the molten thermoplastic resin P is moved from the nozzle 6 to the resin passage of the nozzle touch body 65 by moving the screw 7 forward.
It is injected into 69. The injected molten resin P flows from the outlet 70 of the resin passage 69 in the nozzle touch body 65 to the annular groove 71.
Through the branch passage 73 of the resin passage 72 of the extension manifold main body 63, through the resin passage 72 of the extension manifold main body 63 and guided into the runner 47 of the main manifold 46. The resin P is distributed by this runner 47,
It passes through the bushes 49, 50 and flows into the cavities 15, 16 from the gates 51, 52. After such an injection step, a pressure holding step is performed, and pressure is applied to the resin P filled in the cavities 15 and 16 from the injection molding machine side by pressing the screw 7. After the pressure-holding process is completed, the injection molding machine side starts the measuring process, and the screw 7 turns back. At the same time, after the pressure holding step, the resin P filled in the cavities 15 and 16 is sufficiently cooled and solidified, and then, as shown in FIG. The movable mold 13 opens with respect to the intermediate mold 12. As the fixed mold 11 and the intermediate mold 12 are opened, the nozzle 6 is separated from the nozzle touch body 65 of the extension manifold 61. Along with this, as shown in FIG. 3, the extension 67 moves to the right by the bias of the spring 67. As a result, the inlet portion 74 of the resin passage 72 of the extension manifold main body 63 and the nozzle touch body 65 are
The annular groove 71 passing through the outlet portion 70 of the resin passage 69 is displaced from each other. The inlet portion 74 is closed by the outer peripheral surface 65a of the nozzle touch body 65, and the outlet portion 70 is closed by the inner peripheral surface 64a of the fitting hole 64 of the extension manifold body 63. In this way, the resin passage 72 of the extension manifold main body 63 and the resin passage 69 of the nozzle touch body 65 are cut off from each other.
When the nozzle touch body 65 projects from the fitting hole 64 of the extension manifold body 63, air enters the fitting hole 64 from the outside through the air escape hole 68. With this,
As the mold is opened, the molded product, which is the resin P solidified in the cavities 15 and 16, separates from the mold plates 44 and 45, and is ejected by the ejecting pins 26 and 36 to separate from the mold plates 24 and 34 and taken out. After that, the mold is clamped again as described above, and the molding is repeated. During such a molding cycle,
The resin P in the resin passages 69 and 72 of the extension manifold 61 is always kept in a molten state by the heating of the band heater 75.
The resin P in the runner 47 of the main manifold 46 is also kept in a molten state by the heating of the heater 48. The gates 51 and 52 are open during the injection process and the pressure holding process, but are closed by the valve pins 53 and 54 at other times.

By the way, as described above, when the mold is opened, the extension manifold 61 and the nozzle 6 of the injection molding machine are separated from each other. At this time, at a position where the resin passages 69 and 72 of the extension manifold 61 are close to the nozzle 6. Because it is blocked,
Despite the pressure of the molten resin P in the manifolds 46 and 61, the molten resin P in the extension manifold 61 hardly leaks. Even if it leaks, the resin passage 69 of the nozzle touch body 65
The resin inside leaks only slightly. With this,
Air does not enter the resin passages 69 and 72 of the extension manifold 61. It should be noted that, as described above, when the resin drips to the outside from the resin passage 69 of the nozzle touch body 65 to some extent, it is possible to more reliably prevent the entrainment of air during the subsequent connection of the nozzle 6. Since a large amount of resin leakage can be prevented as described above, no trouble occurs when the extension manifold 61 and the nozzle 6 are butted against each other. Further, since the entrainment of air can be prevented, defective molding can be prevented. Moreover, the structure of the valve device 62 for that purpose is simple.
That is, the spring 67 is used to operate the nozzle touch body 65 in conjunction with the connection and separation of the nozzle 6 to open and close the resin passages 69 and 72 of the extension manifold 61, so that the structure of the valve device 62 can be simplified. . Moreover, the operation of the valve device 62 is reliable. Further, with the opening and closing of the valve device 62, the volume of the resin passage 72 on the extension manifold main body 63 side and the volume of the resin passage 72 on the nozzle touch body 65 side do not change at all. That is, the amount of the molten resin P on the extension manifold main body 63 side does not change, and the pressure thereof does not change.

The present invention is not limited to the above embodiment, but various modifications can be made. For example,
In the above embodiment, the nozzle touch body 65 is slidably fitted to the inner peripheral side of the extension manifold body 63, but conversely, the nozzle touch body is slidably fitted to the outer peripheral side of the extension manifold body 63. Of course, it is possible. Further, in the above embodiment, the nozzle 6 of the injection molding machine itself is directly and detachably connected to the extension manifold 61 fixed to the main manifold 46 as the mold is clamped and opened. May be fixed, and this relay nozzle may be always connected to the nozzle of the injection molding machine, and the relay nozzle may be attached to and detached from the extension manifold with mold clamping and mold opening. Further, although the gates 51 and 52 are opened and closed by the valve pins 53 and 54 in the above-described embodiment, they may be opened and closed by a spear.

[0016]

According to the present invention, in the hot runner mold, the extension manifold between the nozzle of the injection molding machine and the main manifold is an extension manifold body fixed to the main manifold and the tip of the extension manifold body. A nozzle touch body to which a nozzle on the injection molding machine side is detachably connected and which is slidably fitted in the mold opening and closing direction,
The resin passages in the extension manifold main body and the nozzle touch body are sliding surfaces of the extension manifold main body and the nozzle touch body, and when the nozzle touch body moves to the main manifold side and overlaps with each other when the nozzle touch body moves to the opposite side. Since the nozzle touch body is urged toward the opposite side of the main manifold from the extension manifold main body by opening each at a position away from each other, for example, when the nozzle on the injection molding machine side is separated from the extension manifold due to mold opening, By blocking the resin passage between the extension manifold main body and the nozzle touch body, the resin hardly leaks from the resin passage of the extension manifold, and it is possible to prevent air from entering the resin passage. If some resin drips outside from the resin passage of the nozzle touch body Winding can be more reliably prevented in the air at the time of connection. By preventing resin leakage and air entrapment in this way, mold clamping obstacles and molding defects can be prevented. Moreover, since opening and closing of the resin passage is performed in conjunction with attachment / detachment of the nozzle by the spring, the structure of the valve device can be simplified and the volume of each resin passage can be changed without any change.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a hot runner die of the present invention.

FIG. 2 is a cross-sectional view of a tip end portion of an extension manifold in the same mold clamping state.

FIG. 3 is a cross-sectional view of the tip of the extension manifold in the mold open state.

FIG. 4 is a sectional view taken along line AA of FIG.

FIG. 5 is a side view of a part of the injection molding machine having the mold attached thereto.

[Explanation of symbols]

 6 Nozzle 11 Fixed mold (mold body) 12 Intermediate mold (mold body) 13 Movable mold (mold body) 15 Cavity 16 Cavity 46 Main manifold 47 Runner (resin passage) 61 Extension manifold 63 Extension manifold body 64a Inner surface (Sliding surface) 65 Nozzle touch body 65a Outer peripheral surface (Sliding surface) 67 Spring 69 Resin passage 72 Resin passage

Claims (1)

[Claims] 1. A plurality of mold bodies that open and close each other to form a cavity inside during mold clamping, a main manifold provided in one of the mold bodies, and an injection molding machine connected to the main manifold. Side nozzle is detachably connected to the extension manifold, the main manifold has a resin passage to the cavity, and the extension manifold includes a resin injected from the nozzle on the injection molding machine side. In a hot runner mold which has a resin passage inside which flows to the resin passage of the main manifold and always keeps the resin in the resin passage of these manifolds in a molten state, the extension manifold is an extension manifold body fixed to the main manifold. And the end of the extension manifold body on the side opposite to the main manifold is slidably fitted in the opening and closing direction of the mold. And a nozzle touch body to which the nozzle on the injection molding machine side is detachably connected, and the resin passage in the extension manifold body and the nozzle touch body,
It is a sliding surface between the extension manifold main body and the nozzle touch body, and when the nozzle touch body moves to the main manifold side, they overlap each other and when they move to the opposite side, they are opened to positions that separate from each other. A hot runner mold characterized in that the nozzle touch body is biased by a spring to the side opposite to the main manifold.