JP2005262759A - Nozzle for injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle for an injection molding machine capable of exactly simultaneously bringing a nozzle having a plurality of nozzle openings into contact with a mold having a plurality of sprues. <P>SOLUTION: Two nozzle tips 10 and 20 are attached to a nozzle body 4. The first nozzle tip 10 is a general nozzle tip having a spherical surface at the tip end. The second nozzle tip 20 is composed of a base member 21, a head member 22, a disc spring 23 and a cap 23. An inner hollow portion 21a for a molten resin to flow through is formed on the central axis of the base member 21. The head member 22 is connected to the downstream side of the base member 21. The head member 22 has an axial portion 22a, a flange portion 22b and a nose portion 22c orderly from the upstream side. The axial portion 22a is inserted into the inner hollow portion 21a of the base member 21 to move in the axial direction. The nose portion 22c is connected to the back surface of a mold at the downstream side end. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a nozzle used in an injection molding machine, and in particular, for an injection molding machine having a plurality of nozzle openings so as to be used for a mold having two or more sprues for introducing a molten resin. Related to the nozzle.

  FIG. 3 shows a structure described in Japanese Patent Application Laid-Open No. 07-227878 as an example of a conventional nozzle for an injection molding machine (Patent Document 1).

  This nozzle is used when performing injection molding using two kinds of resins. The nozzle includes a merging nozzle 33 and a nozzle 34 and is connected to the first injection unit 31 and the second injection unit 32. The merge nozzle 33 is used when the resin from the first injection unit 31 and the second injection unit 32 is merged and injected, and the nozzle 34 is used when only the resin from the second injection unit 32 is injected alone. used.

  When injection molding is performed using such nozzles, if the joining nozzle 33 and the nozzle 34 do not touch the corresponding spurs on the mold side accurately at the same time, the resin from the incompletely connected nozzle will be used. Leakage occurs. Therefore, the merging nozzle 33 and the nozzle 34 are such that the parallelism of the axial centers, the distance between the axial centers, and the axial dimension of the tip surface touching the mold exactly match the corresponding sprue on the mold side. Needs to be manufactured and assembled.

In general, since a plurality of molds are used in an injection molding machine, it is necessary to ensure the accuracy not only on the nozzle side but also on the mold side. In this regard, in recent years, the accuracy of processing machines has increased, and it has become relatively easy to ensure these dimensional accuracy. However, the axial dimension of the nozzle gradually changes due to wear associated with use. For this reason, if there is a difference in the axial dimension due to the difference in the wear amount between the merging nozzle 33 and the nozzle 34, it becomes difficult to ensure the nozzle touch pressure simultaneously with the two nozzles, and the wear amount. Resin leaks from the larger nozzle.
Japanese Patent Application Laid-Open No. 07-227878

  The present invention has been made in view of the above-described problems of conventional nozzles for injection molding machines, and an object of the present invention is to provide a plurality of nozzle openings for a mold having a plurality of sprues. Another object of the present invention is to provide a nozzle for an injection molding machine that can reliably touch the nozzle.

The nozzle for an injection molding machine of the present invention is
An injection molding machine nozzle having a plurality of discharge ports for injecting resin into a mold,
A first nozzle tip having a spherical tip is attached to the tip of one of the discharge ports,
A second nozzle tip is attached to the tip of the other discharge port,
This second nozzle tip
A base member having a lumen through which molten resin flows;
A head member connected to the downstream side of the base member, and having a shaft portion, a flange portion, and a nose portion in order from the upstream side, and the shaft portion is slidably inserted into the lumen portion in the axial direction;
A spring element mounted in a compressed state between the downstream end surface of the base member and the upstream end surface of the flange portion of the head member;
A cap for holding the head member from the outer peripheral side and attaching the head member and the spring element to the base member;
It is provided with.

  In the nozzle for an injection molding machine of the present invention, the head member can advance and retract in the axial direction with respect to the base member in the second nozzle tip. Therefore, even if the axial dimensions of the first nozzle tip and the second nozzle tip change with the progress of wear, the nozzle touch pressure on the back surface of the mold can be secured. Furthermore, according to the nozzle for an injection molding machine of the present invention, since the allowable range of the difference in the axial dimension between the first nozzle tip and the second nozzle tip is widened, the first nozzle tip, the second nozzle tip, and the mold The demand for the processing accuracy of the sprue can be relaxed.

  Preferably, the shaft portion of the head member is thinned so that the shaft portion is in close contact with the wall surface of the lumen portion of the base member by the pressure of the molten resin flowing inside to maintain a sealed state. If comprised in this way, the request | requirement with respect to the dimensional accuracy of the part which the axial part of the said head member fits in the internal cavity part of the said base member can be eased.

  Preferably, the tip of the nose portion of the head member is a spherical surface.

  According to the nozzle for an injection molding machine of the present invention, it is possible to reliably and easily touch a nozzle having a plurality of nozzle openings to a mold having a plurality of sprues.

  1 and 2 show an example of a nozzle for an injection molding machine according to the present invention. FIG. 1 is a schematic view of the overall configuration of an injection molding machine nozzle, and FIG. 2 is an enlarged view of a nozzle tip portion of the injection molding machine nozzle. In the figure, 10 is a first nozzle tip, 20 is a second nozzle tip, 21 is a base member, 22 is a head member, 21a is a lumen, 22a is a shaft, 22b is a flange, 22c is a nose, and 23 is A disc spring (spring element), 24 represents a cap.

  This nozzle for an injection molding machine is configured to inject two types of resins supplied from the first injection unit 1 and the second injection unit 2 into a mold through flow paths formed separately inside. It is used for multicolor (multi-material) molding and marble molding.

  This nozzle for an injection molding machine is composed of a connecting block 3, a nozzle body 4, a first nozzle chip 10, a second nozzle chip 20, and the like, and has two discharge ports for injecting resin into a mold. Yes. The first injection unit 1 and the second injection unit 2 are connected to the upstream end surface of the nozzle body 4 via the connecting block 3. Two nozzle tips 10 and 20 are attached to the downstream end face of the nozzle body 4. Among these, the first nozzle tip 10 is a conventional general nozzle tip, and the tip thereof is constituted by a spherical surface. On the other hand, the 2nd nozzle tip 20 is comprised by combining a some member (21-24), as shown in FIG.

  In other words, the second nozzle tip 20 includes a base member 21, a head member 22, a disc spring 23, and a cap 24. The base member 21 is formed with a lumen 21a on the central axis through which the molten resin sent from the injection unit flows. A head member 22 is connected to the downstream side of the base member 21. The head member 22 has a shaft portion 22a, a flange portion 22b, and a nose portion 22c in order from the upstream side. The shaft portion 22a of the head member 22 is inserted into the lumen portion 21a of the base member 21, and can slide in the axial direction. The nose portion 22c of the head member 22 is connected to a sprue provided on the back surface of a mold (not shown) at the downstream end thereof. In this example, the tip of the nose portion 22c is a spherical surface.

  Between the downstream end surface of the base member 21 and the upstream end surface of the flange portion 22b of the head member 22, a plurality of stacked disc springs 23 are mounted in a compressed state. The nose member 22 and the disc spring 23 are held by the cap 24 from the outer peripheral side and are attached to the base member 21.

  Since the second nozzle chip 20 has the fitting portions (21 a, 22 a) in the axial direction, the head member 22 can advance and retract in the axial direction with respect to the base member 21. Therefore, even if there is a difference in the axial dimension between the first nozzle tip 10 and the second nozzle tip 20, the difference is absorbed by the disc spring 23. The back of the can be touched. That is, when this nozzle for an injection molding machine is pressed against the back surface of the mold, the second nozzle tip 20 is axially moved with reference to the joint between the spherical surface at the tip of the first nozzle chip 10 and the sprue on the back surface of the mold. The position is adjusted by moving, and the two nozzle tips (10, 20) are accurately joined to the two sprues on the back surface of the mold.

  Further, in this example, the cross-sectional shape of the shaft portion 22a of the head member 22 is formed such that the inner diameter gradually increases toward the upstream side, so that the thickness gradually decreases toward the upstream side. . For this reason, when the shaft portion 22a is deformed by the pressure of the molten resin inside, the seal of the fitting portion between the shaft portion 22a and the lumen portion 21a is secured, and resin leakage from the fitting portion is prevented. The

  In the above description, the nozzle having two discharge ports has been described as an example. However, the structure of the present invention can be applied to a nozzle having three or more discharge ports. That is, in the case of an injection molding machine nozzle having three or more discharge ports for injecting resin into the mold, the first nozzle tip 10 (conventional nozzle) is formed at the tip of one of the discharge ports. Tip) and the second nozzle tip 20 is attached to the tip of the other discharge port. Thereby, each discharge port can be simultaneously and reliably touched on the back surface of the mold.

The figure which shows an example of the nozzle for injection molding machines based on this invention. The enlarged view of the nozzle tip part of the nozzle for injection molding machines shown in FIG. The figure which shows an example of the nozzle for conventional injection molding machines.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st injection unit, 2 ... 2nd injection unit, 3 ... Connection block, 4 ... Nozzle body, 10 ... 1st nozzle tip, 20 ... 2nd nozzle tip, 21 ... Base member, 22 ... Head member, 21a ... Lumen, 22a ... Shaft, 22b ... Flange, 22c ... Nose, 23 ... Disc spring ( Spring element), 24 ... cap, 31 ... first injection unit, 32 ... second injection unit, 33 ... confluence nozzle, 34 ... nozzle.

Claims (3)

An injection molding machine nozzle having a plurality of discharge ports for injecting resin into a mold,
A first nozzle tip having a spherical tip is attached to the tip of one of the discharge ports,
A second nozzle tip is attached to the tip of the other discharge port,
This second nozzle tip
A base member having a lumen through which molten resin flows;
A head member connected to the downstream side of the base member, and having a shaft portion, a flange portion, and a nose portion in order from the upstream side, and the shaft portion is slidably inserted into the lumen portion in the axial direction;
A spring element mounted in a compressed state between the downstream end surface of the base member and the upstream end surface of the flange portion of the head member;
A cap for holding the head member from the outer peripheral side and attaching the head member and the spring element to the base member;
A nozzle for an injection molding machine, comprising:   The shaft portion of the head member is thinned so as to be in close contact with the wall surface of the inner cavity portion of the base member by the pressure of the molten resin flowing inside the head member to maintain a sealed state. Nozzle for injection molding machine described in 1.   The nozzle for an injection molding machine according to claim 1, wherein a tip of a nose portion of the head member is formed of a spherical surface.

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