JPS60168619A - Injection molding device - Google Patents

Abstract

PURPOSE:To keep molten resin passing through a hot runner at a uniform state by preventing heat diffusion to a mold from the hot runner, by supporting the hot runner in an energizing state in the direction receding from an injection position to the mold. CONSTITUTION:A locate ring 23 is secured to an accommodating part 13 of a stationary side mold 6 and a flange 25 of a hot runner 21 is fixed to said locate ring 23 with a bolt 24 through a spring component 27. The hot runner 21 is energized in the rightward direction by the spring component 27 at the time other than injection. At the time of the injection, an injection unit 8 is pressed against a nozzle receiving part 11, the hot runner 21 is made to move in the leftward direction, a gate part 4 is made to stick to a gate receiving part 5 and molten resin is injected within a cavity through a passage 12. As the hot runner and the mold are detached thermally from the titled device and there is no heat diffusion to the mold from the hot runner at the time other than the injection, the molten resin in the hot runner can be kept uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Division of the Invention> The present invention relates to an injection molding apparatus, and particularly to an injection molding apparatus that can maintain a uniform state of molten resin passing through a hot runner.

<Prior Art and Problems> Various types of injection molding apparatuses are used for molding thermoplastic resin, and a typical example of this injection molding apparatus is shown in FIG. This injection device is composed of a fixed side 6 and a movable side 7 which is arranged opposite to the fixed side and forms a cavity for resin molding therebetween, and a mold having a storage chamber 13 on the fixed side 6. , has a gate part 4 at the axial tip, a nozzle receiving part 11 at the rear end, has a resin passage 12 inside extending from the nozzle receiving part 11 to the gate part 4, and is installed in the storage chamber 13. It consists of a hot runner H and an injection unit 8 which has a nozzle part 8a that fits into the nozzle receiving part 11 of the hot runner H and injects molten resin by coming into contact with the hot runner H. The hot runner H has a substantially cylindrical main body 2 with a resin passage 12 formed therein, and a torpedo 1 extending in the axial direction approximately at the center of the resin passage 2. It has an approximately bullet-like external shape that gradually tapers. Further, the hot runner H is firmly fixed to the stationary side in the accommodation chamber with the gate portion 4 tightly fitted to the gate receiving portion 5 formed at the resin outlet portion of the stationary side 6. Furthermore, an electric heating element 10, such as a Nitarom wire, is embedded in the torpedo 1. During the resin molding operation, the injection unit 8 moves forward in the axial direction and the nozzle portion 8a fits into the nozzle receiving portion 11, whereby molten resin is fed into the hot runner 11. This molten resin is kept warm or heated by the torpedo 1 and is injected into the cavity 9 of the mold in a molten state.

However, in such a conventional injection molding apparatus, among the resin passing through the hot runner H, the resin passing through a portion in contact with or close to the torpedo 1 is transferred to the main body 2.
The temperature is higher than that of the resin passing through the area adjacent to the inner wall surface of the
Therefore, since the viscosity is low, during injection, the resin near the torpedo 1 is preferentially injected into the cavity 9, while the resin near the inner wall surface 3 stagnates and is heated for a long time. . Therefore, when molding a resin with poor thermal stability, such as a vinyl chloride resin or a resin to which a flame retardant is added, there are problems such as the resin changing color or decomposing. In addition, in order to eliminate accumulation near the inner wall surface 3, the main body 2
Even if a heater is attached to the outer periphery of the main body 2 to heat it, the gate part 4 is always in contact with the mold, so the heat is absorbed by the mold, and the effect of heating the outer periphery of the main body 2 is weak, and conversely, the gate part 4 of the mold is heated. The temperature of part 5 rises, and it takes a long time to cool down after injection of molten feces fat.
There were problems such as a decrease in work efficiency.

<Object of the Invention> The present invention has been made by focusing on the conventional problems as described in B above.The purpose of the present invention is to configure the hot runner so that the molten resin can easily pass through the inside of the hot runner, and to The object of the present invention is to solve the above-mentioned conventional problems by providing an injection molding apparatus that can maintain a uniform state of molten resin passing therethrough.

<Structure of the Invention> In order to achieve the above object, the present invention disposes a hot runner so as to be slidable in the axial direction within a housing chamber provided in an injection mold, A gate receiving part is formed at the exit part, and the hot runner is always elastically supported by an elastic member in the direction of retreating from the injection position with respect to the mold, and the hot runner is elastically supported by the collision pressure of the nozzle part due to the advancement of the injection unit. The gist of the pot runner is to move forward against the member so that the gate part of the pot runner fits into the gate receiving part of the mold. The hot runner can be elastically supported by, for example, providing a flange extending perpendicularly to the axis at the base end, that is, the rear end portion of the hot runner, and engaging a spring member acting in the backward direction of the hot runner on the flange surface. Let's go. That is, a through hole is formed in the flange of the hot runner, and a bolt is inserted loosely into the through hole.
By screwing and fixing the bolts into the mold, the hot runner can be guided by the bolts and slide in the axial direction. Furthermore, if a compression coil spring is installed as an elastic member between the head of the bolt and the flange surface, the hot runner will always be biased in the direction of retreat from the position where it is tightly fitted into the mold gate receiver during injection operation. This makes it possible to thermally separate the hot runner and the mold except during injection to prevent unnecessary heat diffusion.

<Description of Embodiments> An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 2 and 3 are diagrams showing an embodiment of the present invention.

The injection molding apparatus according to the embodiment B is composed of a fixed side 6 and a movable side disposed opposite to the fixed side 6, and includes a mold having a housing chamber 13, and a shaft inside the housing chamber 13. The hot runner 21 is installed so as to be slidable in the direction, and the injection unit 8 contacts the hot runner 21 to inject hot molten resin, and elastically supports the hot runner 21 in the direction of retreating from the injection position. Become. The hot runner 21 fits into the gate portion 4 at its axial tip and into the nozzle portion 8a of the injection unit 8 at its rear end. A hot runner 13 is formed inside the nozzle receiving part 11 from the nozzle receiving part 11 to the gate part.
It has a resin passageway 12 that extends through it in the axial direction.

This hot runner 21 has a rear end portion, that is, a nozzle receiving portion 1.
a flange 25 extending perpendicularly outward in a position proximate to 1;
is formed, and this flange 25 is made of a material with low thermal conductivity (
For example, it is made of stainless steel) and has a predetermined number of through holes 26 formed therein. The bolt 24 is pushed through the through hole 26 in a loosely fitted state, and the bolt 24 is inserted into the fixed side 6.
is screwed and fixed to the locate ring 23 fixed to the
A hot runner 21 is supported by a bolt 24 so as to be slidable in the axial direction. Furthermore, bolt 24 head and hot runner 2
An elastic member, that is, a coiled spring member 27 is attached between the flange 25 of the hot runner 21 and the flange 25 of the mold. force and press it against the locate ring 23. As a result, the gate portion 4 of the hot runner 21 is separated from the gate receiving portion 5 of the mold, so that the hot runner 21 and the mold are thermally insulated.

On the other hand, a band heater 22 is wrapped around the outer circumference of the hot runner 21, and a temperature regulator 28 is embedded in the hot runner 21, so that the hot runner 21 is heated while being automatically adjusted to a predetermined temperature. Therefore, in normal times, heat is not transferred from the hot runner 21 to the mold, and the hot runner 21 can be maintained in a good condition.

Note that an opening 29 is formed in the center of the locate ring 23 so that the injection unit 8 can come into contact with the hot runner 21 installed in the mold.

In the injection molding apparatus having such a configuration, to perform injection molding, first, when the injection unit 8 moves forward in the direction of arrow A, the hot runner 21 is moved by the pressing force of the nozzle portion 8a.
It moves forward against the acting force of the top spring member 27, and as shown in FIG. 3, the gate portion 4 comes into contact with the gate receiving portion 5 of the mold and is pressed. In the state B, the injection unit 8
The molten resin supplied from J is injected into the cuvette 9, and the amount of injection is measured by rotating a screw (not shown). When the measurement of the injection amount is completed and the injection unit 8 retreats in the direction of arrow B in the figure, the pot runner 21 slides in the direction of arrow B by the acting force of the spring member 27, and the gate part 4 is moved away from the gate receiving part 5. Separate.

Since this operation is repeated for each cycle of injection molding, the heat from the hot runner is easily transmitted to the mold and prevented from spreading, making it possible to continuously mold even resins with poor thermal stability without any problems. .

Note that in this embodiment, the spring member 27 is connected to the bolt 24.
It is installed between the head and the flange 25, but unlike this, the flange is interposed between the mold contact surface (indicated by 6a in the figure) in the storage chamber 13 and the flange 25. 25
may be pressed.

In the case of B, the spring member includes not only a small-diameter compression coil spring like the spring member 27 but also a coil spring having an inner diameter larger than the outer diameter of the hot runner 21 in contact between the mold contact surface 6a and the flange 25. You may let them. Furthermore, if a shutoff valve is attached to the nozzle part 8a of the injection molding machine, the injection unit 1-8 can be retreated at the time of completion of injection before metering by rotating the screw, which further reduces the diffusion of heat to the mold. It becomes possible to prevent this. Also, even if a plurality of gates are required, it can be implemented easily as shown in FIG. In addition, reference numbers that are the same as those in Figure 4 of the inner tube 2 and Figure 3 indicate the same parts, and reference numbers with a dash are the same parts as those without a dash. Show that something is true.

<Effects of the Invention> As explained above, according to the present invention, since the hot runner of the injection molding apparatus is configured to move forward and backward within the mold, the diffusion of heat from the hot runner to the mold is prevented. The molten resin flowing inside the hot runner can always be kept in a uniform state, making it possible to perform good injection molding.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional example of an injection molding apparatus, FIG. 2 is a diagram showing a state when the hot runner of an injection molding machine according to an embodiment of the present invention is retracted, and FIG. 3 is a diagram showing a hot runner in the above embodiment. FIG. 4, which shows the state when the runner moves forward, is a diagram showing an embodiment in which a plurality of gates are provided. 1...1...Peed, 2...Body, 4...
...Gate part, 5...Gate receiving part, 6...
・・Fixed side mold, 7・・・Movable side mold, 8・・・・
・Injection unit, 9...Mold cavity, 13...
...accommodation section, 21. H・・・Hot runner, 2
4... Bolt, 25... Flange, 2
7... Spring member (elastic member). Figure 1 Figure 3 Figure 4 Procedural amendment (Mr. Kazuo Wakasugi, Commissioner of the Ship's Patent Office1, Indication of the case, 1982 Patent Application No. 256082, Name of the invention Injection molding device 3, Make amendments) Patent applicant: Orio Seihi Seifu F4 Seven Type Company 4, Agent: Toranomon Jitsugyo Kaikan (8151), 1-1-20 Toranomon, Minato-ku, Tokyo, 105, Japan Patent attorney Nnishi Su 1-1 Telephone: 591) 1516 (Representative) (and 2 others) 5. Subject of amendment (1) Section ``Claims'' of the specification (2) Section 1 of ``Detailed Description of the Invention J'' of the specification The scope of the claims is amended as follows: Claims 1) A mold consisting of a fixed side and a movable side and having a storage chamber on the fixed side, a gate part at the axial tip, and a nozzle receiver at the rear end. a hot runner that is installed in the storage chamber, and an injection device that injects hot molten resin by contacting the nozzle receiving portion of the hot runner; In an injection molding apparatus consisting of a unit, a hot runner is arranged to be slidable in the axial direction within a housing chamber, and a gate receiving part is formed at the resin outlet part of the mold, and the hot runner is attached to the mold by an elastic member. The hot runner is always elastically supported in the direction of retreating from the injection position, and the hot runner moves forward against the elastic force due to the collision pressure of the nozzle part caused by the straight movement of the injection unit, and the gate of the hot runner is An injection molding apparatus characterized by this, which fits into the gate receiving part of the mold. 2) The hot runner is provided with a flange extending in a direction perpendicular to the axis at the rear end portion of the hot runner, and the flange surface 2. The injection molding apparatus according to claim 1, wherein the injection molding apparatus is elastically supported by engaging a spring member that acts in the backward direction of the hot runner." 2. Specification, page 9, line 2. Correct ``21 mo tama'' to ``21 mo ta.''

Claims (1)

[Scope of Claims] l) A mold consisting of a fixed side and a movable side and having a storage chamber on the fixed side, a gate portion at the axial tip, a nozzle receiving portion at the rear end, and a nozzle receiving portion inside. An injection molding apparatus comprising a hot runner having a resin passage extending from the housing chamber to the gate portion, and an injection unit that injects hot molten resin by contacting a nozzle receiving portion of the hot runner. While the hot runner is arranged to be able to slide in the axial direction indoors, a gate receiving part is formed at the resin outlet part of the mold, and the hot runner is moved in the direction of retreat from the injection position with respect to the mold by an elastic member. The hot runner is always elastically supported, and the hot runner moves forward against the elastic member due to the collision pressure of the nozzle part due to the front part of the injection unit, so that the gate part of the hot runner fits into the gate receiving part of the mold. An injection molding device featuring: 2) The hot runner is provided with a flange extending perpendicularly to the axis at the rear end portion of the hot runner, and is elastically supported by engaging a spring member acting in the backward direction of the hot runner with the flange surface. An injection molding apparatus according to claim 1, characterized in that: