JPH1148286A - Nozzle structure of injection molder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit damage of a nozzle by a method wherein a second annular contact surface of a nozzle comes in contact with a second annular contacted surface of a mold, a cylindrical projected part of the nozzle is inserted into a cylindrical recessed part of the mold, and a first annular contact surface of the nozzle comes in contact with a first annular contacted surface of the mold. SOLUTION: A first annular contact surface 16a, a cylindrical projected part 16b and a second annular contact surface 16c are formed at a tip part of a nozzle body 16. In the first annular contact surface 16a, a globular projected surface is made around an opening 6a, the cylindrical projected part 16b is a conical surface of which a diameter is gradually reduced to forward, and the second annular contact surface 16c is globular projected surface. A passage of the nozzle body 16 is composed of a cylindrical part 16d1 connected to a passage 15a of a nozzle principal body 15, and a part 16d2 of which a diameter is gradually enlarged toward the tip. Then, the cylindrical projected part 16b is inserted in an almost close adhesion state into a cylindrical recessed part 17b under a state wherein the second annular contact surface 16c sticks close to a second annular contacted surface 17c, and the first annular contact surface 16a is brought in contact with a first annular contacted surface 17a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nozzle structure of an injection molding apparatus, and more particularly to a nozzle structure of an injection molding apparatus suitable for a thermoplastic material having a high melting temperature.

[0002]

2. Description of the Related Art As a nozzle structure of a conventional injection molding apparatus, there is known a nozzle structure shown in cross section in FIG.
That is, at the tip of the nozzle 50 of the injection molding machine, an annular contact surface 51 formed of a spherical surface is formed substantially orthogonal to the central axis of the nozzle 50, and the annular contact surface 51 contacts the sprue bush 57 in which the sprue 56 of the mold 55 is opened. An annular contact surface 58 formed of a spherical surface having a larger diameter than the surface 51 is formed substantially perpendicular to the central axis of the sprue 56. The base end of the nozzle 50 is screwed to a cylinder (not shown) of the injection molding machine. Thus, the annular contact surface 51 of the nozzle 50 is
The thermoplastic material A in a molten state is injected from the nozzle 50 toward the sprue 56 and, consequently, the cavity of the mold 55 in a state of being brought into contact with the annular contact surface 58.

Further, an opening 56a on the base end side of the sprue 56 is provided.
Has a larger cross-sectional area than the opening 50a on the tip side of the flow path 50b of the nozzle 50. This is to facilitate the removal of the thermoplastic material A cooled and solidified in the sprue 56.

However, the nozzle structure of such a conventional injection molding apparatus has the following technical problems. (1) When the thermoplastic material A in the molten state is injection molded, the annular contact surface 51 of the nozzle 50 of the injection molding machine has the annular shape of the mold 55 in the high temperature state heated by the thermoplastic material A in the molten state. It comes into strong contact with the contact surface 58. For this reason,
The tip of the nozzle 50 is deformed so that the annular contact surface 51 is pushed in, and the nozzle 5 is repeatedly formed by injection molding.
A gap is created between the 0 annular contact surface 51 and the annular contact surface 58 of the mold 55, and the molten thermoplastic material A is ejected. Such a jetting accident is likely to occur when a thermoplastic material A having a high melting temperature is used. For example, a light alloy (a metal such as magnesium, aluminum, zinc, or lead, or an alloy thereof) is used as the thermoplastic material A. Is the case.

[0005] (2) The nozzle 50 forms an integral
Since the base end of the nozzle 50 is screwed to the cylinder of the injection molding machine, when the tip of the nozzle 50 is deformed, the entire nozzle 50 is ejected before the thermoplastic material A is ejected. It must be replaced with a new one. For this reason,
The replacement work of the nozzle 50 is frequently required, which is not only complicated but also uneconomical.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional technical problems, and has the following configuration. According to the first aspect of the present invention, the thermoplastic material A in the cylinder 2 is supplied to the nozzle 2 while the tip of the nozzle 6 connected to the tip of the cylinder 2 of the injection molding machine is in contact with the connection 17 of the mold 7. 6 is a nozzle structure of an injection molding apparatus for injecting from the flow paths 15a and 16d of the mold 6 toward the sprue 8 of the mold 7, and is provided at the tip of the nozzle 6 in a direction substantially perpendicular to the center axis of the nozzle 6 in order from the tip side. A first annular contact surface 16a, a cylindrical convex portion 16b projecting so that the central axis is aligned with the nozzle 6, and a second annular contact surface 16c substantially perpendicular to the central axis of the nozzle 6 are formed. Part 1
7, a first annular contact surface 17a substantially orthogonal to the center axis of the sprue 8 in order from the distal end side, a cylindrical concave portion 17b for aligning the center axis with the sprue 8, and a second annular surface substantially orthogonal to the center axis of the sprue 8. In the state where the contact surface 17c is formed and the second annular contact surface 16c of the nozzle 6 is in contact with the second annular contact surface 17c of the mold 7, the cylindrical convex portion 16 of the nozzle 6 is
b is inserted into the cylindrical concave portion 17b of the mold 7, and the first annular contact surface 16a of the nozzle 6 becomes the first annular contact surface 17a of the mold 7.
, The flow paths 15a and 16d of the nozzle 6 communicate with the sprue 8 in the nozzle structure of the injection molding apparatus. The second annular contact surface 16 of the nozzle 6
c is in contact with the second annular contact surface 17c of the mold,
A gap δ is formed between the first annular contact surface 16a of the nozzle 6 and the first annular contact surface 17a of the mold 7, and is defined by the cylindrical recess 17b of the mold 7, and the gap δ is formed in the gap δ. , Flow path 15
a, 16d and the thermoplastic material A flowing through the sprue 8 can be filled, and the opening 8a on the base end side of the sprue 8 can be filled.
Is an opening 6a on the tip side of the flow paths 15a and 16d of the nozzle 6.
2. The nozzle structure of the injection molding apparatus according to claim 1, wherein the nozzle structure has a shape that can be connected without having a step. The nozzle 6 has a nozzle body 15 connected to the tip of the cylinder 2 and a nozzle body 16 screwed to the tip of the nozzle body 15 by a threaded portion 15b. 3. The nozzle structure of the injection molding apparatus according to claim 1, wherein a first annular contact surface 16a, a cylindrical convex portion 16b, and a second annular contact surface 16c are formed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. First, an outline of the injection molding apparatus will be described with reference to FIG. A screw 4 is arranged inside a cylinder 2 of the injection molding machine 1 so as to be freely rotatable and forward and backward. A nozzle 6 is fixedly provided at the tip of the cylinder 2, and a heater 5 is provided on the outer surface of the cylinder 2. The nozzle 6 includes a nozzle body 15 having a flow path 15a, and a nozzle body 16 having a flow path 16d and screwed to a tip end of the nozzle body 15 by a screwing portion 15b. 15 is the cylinder 2
Is screwed to the distal end of the boss by a screwing portion 15c.

On the other hand, a mold 7 is fixedly mounted on the fixed-side mold mounting plate 10, and a sprue 8 whose leading end communicates with a cavity (not shown) is formed in the mold 7. The sprue 8 is defined by a sprue bush 12 and the sprue bush 1
2 is supported by a locator ring 11 fixed to the mold 7. As shown in FIG. 3, a connection portion 17 is formed in a concave shape on the base end surface of the sprue bush 12 around the opening 8a at the base end of the sprue 8, and the connection portion 17 is connected to the tip end of the nozzle 6 during injection molding. That is, the tip of the nozzle body 16 comes into contact.

As shown in FIG. 2, a first annular contact surface 16a, which is substantially perpendicular to the central axis of the nozzle 6, is projected from the distal end of the nozzle body 16 sequentially from the distal end side, with the central axis aligned with the nozzle 6. A second annular contact surface 16c that is substantially perpendicular to the central axis of the cylindrical projection 16b and the nozzle 6 is formed.
The first annular contact surface 16a is connected to the flow paths 15a, 16
d is formed by a spherical convex surface around the opening 6a at the tip end, the cylindrical convex portion 16b is formed by a conical surface that gradually decreases in diameter toward the front, and the second annular contact surface 16c is formed by a spherical surface. It is formed by a convex surface. Flow path 1 of nozzle body 16
6d is enlarged diameter portion 16 and the cylindrical portion 16d ₁ to be connected to the flow channel 15a of the nozzle body 15, which gradually increases in diameter toward the distal end
d ₂ Tokara is summer.

The openings 6a on the distal ends of the flow paths 15a and 16d of the nozzle 6 have substantially the same shape as the opening 8a on the proximal end of the sprue 8 without any step. Then, as shown in FIG.
In a state where the nozzle 6 to 2 are in contact, sprue 8 connects with gradually reduced in diameter to the enlarged diameter portion 16d ₂ of the flow path 16d of the nozzle body 16, and communicates with the small-diameter cylindrical portion 16d _1.

On the other hand, as shown in FIG. 3, the connecting portion 17 of the mold 7 sequentially aligns the central axis with the first annular contact surface 17a, which is substantially perpendicular to the central axis of the sprue 8, from the distal end side. A second annular contact surface 17c substantially perpendicular to the central axis of the cylindrical recess 17b and the sprue 8 is formed. The first annular contact surface 17a is provided with a first annular contact surface 16a.
Formed by a spherical concave or annular plane of larger diameter than
The cylindrical concave portion 17b is formed so as to conform to the cylindrical convex portion 16b by a conical surface whose diameter gradually decreases toward the front,
The second annular contact surface 17c is formed by a spherical concave surface having a larger diameter than the second annular contact surface 16c.

The second annular contact surface 16c of the nozzle 6
Is in close contact with the second annular contact surface 17c of the mold 7,
The cylindrical convex portion 16b of the nozzle 6 is inserted into the cylindrical concave portion 17b of the mold 7 in a substantially close contact state, and the first annular contact surface 1 of the nozzle 6 is
6a faces the first annular contact surface 17a of the mold 7 with a predetermined gap δ shown in FIG.
The sprues 5a, 16d and the sprue 8 of the sprue bush 12 are connected so that their central axes are aligned. Thus, in a state where the nozzle 6 and the sprue bush 12 are connected, the gap δ formed between the first annular contact surface 16a of the nozzle 6 and the first annular contact surface 17a of the mold 7 is equal to the outer circumference. The portion is defined by at least the cylindrical concave portion 17b of the mold 7.

[0013] When the cylinder 2 is heated by the heater 5 and the tip-shaped thermoplastic material A is supplied into the cylinder 2 while the screw 4 in the cylinder 2 is driven to rotate at a predetermined rotation speed. The thermoplastic material A is gradually fed forward (to the left in the figure) while being melted and kneaded by the function of the screw 4, and is gradually accumulated in the storage portion 2 b at the front end of the cylinder 2. At this time, the screw 4 receives the pressure of the molten thermoplastic material A collected in the storage portion 2b or receives the attractive force of a rotating device and a reciprocating drive device (not shown), and gradually retreats. When the screw 4 is retracted by a predetermined stroke, a predetermined amount of the thermoplastic material A is stored in the storage portion 2b.
Is known to have accumulated in the weighing state. The thermoplastic material A is a metal having a high melting temperature, for example, a metal such as magnesium, aluminum, zinc, or lead, or an alloy thereof.

When a predetermined amount of the thermoplastic material A has been measured and stored in the storage section 2b, the rotation and retreating of the screw 4 are stopped, and the process of plasticizing and measuring the thermoplastic material A is completed. Next, after performing the mold closing and mold clamping steps of the mold 7, a nozzle touching step of bringing the nozzle 6 into contact with the mold 7 is performed as shown in FIG. At this time, the injection molding machine 1 moves forward, and the tip of the nozzle 6, that is, the nozzle body 16
Contact the connecting portion 17 of the sprue bush 12. At the time of the first injection, the gap δ forms a space, and the first annular contact surface 16a of the nozzle 6 is opposed to the first annular contact surface 17a of the mold 7 with a predetermined gap δ interposed therebetween.

Thereafter, the process proceeds to an injection step, in which the screw 4 is advanced. As a result, the molten thermoplastic material A stored in the storage part 2b is supplied to the flow paths 15a, 16
d is injected into the cavity through the sprue 8 of the mold 7. In this case, the gap δ between the first annular contact surface 16a and the first annular contact surface 17a is also provided in the molten thermoplastic material A.
Is filled. Since the cylindrical convex portion 16b and the cylindrical concave portion 17b are inserted and fitted almost in close contact with each other, the nozzle 6
The second annular contact surface 16c of the mold 7 is the second annular contact surface 1 of the mold 7.
The leakage of the thermoplastic material A in the molten state is prevented during this period, in addition to the fact that it is in close contact with 7c. Thereafter, a pressure-holding and cooling step, a mold opening and ejecting step and the like are performed, and the cooled and solidified molded product is taken out of the cavity.

On the other hand, in the pressure-holding and cooling steps, the gap δ
The thermoplastic material A in a molten state filled in the solidification also cools and solidifies,
While forming the filling B, the thermoplastic material A in the sprue 8 is also cooled and solidified. The filler B remains attached to the first annular contact surface 17a of the mold 7 by the retreat of the injection molding machine 1 at the time when the pressure-holding and cooling steps are completed.
This is because the filler B in the gap δ is larger than the contact surface of the first annular contact surface 16a of the nozzle 6
Of the sprue bush 12 and the opening 8 on the proximal end side of the sprue 8 is divided by a wide contact surface comprising a first annular contact surface 17a and a cylindrical concave portion 17b.
a is an opening 6a on the tip side of the flow paths 15a, 16d of the nozzle 6
The reason for this is that the thermoplastic material A is prevented from being cut at the location of the opening 8a of the sprue 8 by having a shape that can be connected without having a step.

When the filler B is separated from the sprue bush 12 and adheres to the first annular contact surface 16a of the nozzle 6, at the time of the next injection step, the flow path 16
Since the thermoplastic material A was cooled and solidified in the enlarged diameter portion 16d ₂ of d is to be emitted toward the cavity, it is not preferred. Therefore, as shown in FIG. 3, an annular corner 17d is positively formed between the first annular contact surface 17a of the sprue bush 12 and the cylindrical concave portion 17b, so that the adhesion of the filler B can be promoted. .

Thus, in order to leave the filler B only in the gap δ, when the injection molding machine 1 is retracted,
The thermoplastic material A, which has been cooled and solidified at least at the distal end portions of 5a and 16d, is left on the sprue 8 side together with the filler B. In the next mold opening and projecting step, the thermoplastic material A that has been cooled and solidified on the sprue 8 side is removed. It is desired to protrude and cut between the filler B. In this regard, in a state where the nozzle 6 is brought into contact with the sprue bushing 12, until the enlarged diameter portion 16d ₂ of the sprue 8 the flow path 16d of the nozzle body 16, so is formed so as to be connected while gradually reduced in diameter, the exit upon retraction of the molding machine 1, the thermoplastic material a was cooled and solidified in the enlarged diameter portion 16d ₂ escapes connexion such a thermoplastic material a and integral cooling solidified in the sprue 8. That is, as shown in FIG.
will be cut in the vicinity of the boundary between the cylindrical portion 16d ₁ of d ₂ and a small diameter. Of course, the heater 5 is provided on the outer surface of the nozzle body 16.
Is not provided. Subsequently, by mold opening and projecting step is carried out, the thermoplastic material A was cooled and solidified by the enlarged diameter portion 16d ₂ of the sprue 8 and the flow path 16d shown in Figure 1 is protruded to the outside of the mold 7, packing B Only shear remains at the gap δ.

Subsequently, a plasticizing / metering step, a mold closing and closing step, a nozzle touching step, an injection step, a pressure-holding and cooling step and the like are repeatedly performed. If the cylinder 2 is advanced along with the nozzle touching process again, the second annular contact surface 16c of the nozzle 6 becomes the second annular contact surface 17c of the mold 7.
, And the cylindrical convex portion 16b of the nozzle 6 is inserted into the cylindrical concave portion 17b of the mold 7 in a substantially close contact state. In addition, nozzle 6
The first annular contact surface 16a is in close contact with the filler B adhering to the first annular contact surface 17a of the mold 7. Filling B
Is usually softer than the sprue bush 12,
In addition to promoting the surface contact, the first annular contact surface 16a
As a result, damage to the first annular contact surface 16a is suppressed as compared with a case where the first annular contact surface 17a of the sprue bush 12 is directly pressed against the first annular contact surface 17a. In addition, to prevent the nozzle 6 from being damaged due to the nozzle touching step, the second annular contact surface 16c contacts the second annular contact surface 17c, the cylindrical convex portion 16b contacts the cylindrical concave portion 17b, and the first annular contact surface 16c contacts the cylindrical concave portion 17b. This is also obtained by the annular contact surface 16a being in contact with the first annular contact surface 17a via the filler B and the contact surface being dispersed and enlarged.

[0020]

As will be understood from the above description,
According to the nozzle structure of the injection molding apparatus according to the present invention, the following effects can be obtained. According to claim 1, the second annular contact surface of the nozzle comes into contact with the second annular contact surface of the mold, the cylindrical convex portion of the nozzle is inserted into the cylindrical concave portion of the mold, and the second annular contact surface of the nozzle. When the one annular contact surface comes into contact with the first annular contact surface of the mold, the contact surface is dispersed and enlarged. As a result, damage to the nozzle due to the nozzle touching process is suppressed,
Since the sealing performance and durability of the nozzle are significantly improved, the accidental ejection of the thermoplastic material in the molten state is suppressed,
It is possible to avoid frequent replacement of the troublesome nozzle. The function of improving the sealing properties and durability of the nozzle is remarkable when a thermoplastic material having a high melting temperature is used in an injection molding apparatus.

According to the second aspect, a gap defined by the cylindrical concave portion of the mold is formed between the first annular contact surface of the nozzle and the first annular contact surface of the mold. The gap is filled with a molten thermoplastic material flowing through the nozzle flow path and the sprue. The thermoplastic material filled in this gap is
Cools and solidifies to form a filling. The opening on the proximal end side of the sprue has a shape that can be connected to the opening on the distal end side of the nozzle flow path without any step. For this reason,
In the mold opening and ejecting process, the thermoplastic material cooled and solidified in the flow path of the nozzle is ejected together with the thermoplastic material cooled and solidified in the sprue, and the filler remains in the gap.

Thus, in the nozzle touching step repeatedly performed thereafter, the first annular contact surface of the nozzle is
It comes into close contact with the first annular contact surface of the mold via the filler. As a result, the contact surface is enlarged as compared with the case where the first annular contact surface is directly pressed against the mold, and damage to the first annular contact surface is suppressed.

According to the third aspect, the nozzle has a nozzle body connected to the tip of the cylinder, and a nozzle body screw-connected to the tip of the nozzle body by a threaded portion. A first annular contact surface, a cylindrical projection, and a second annular contact surface are formed. Therefore, when the first annular contact surface, the cylindrical projection, and the second annular contact surface are damaged, only the nozzle body can be replaced and the nozzle body can be reused.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a nozzle structure of an injection molding apparatus according to one embodiment of the present invention.

FIG. 2 is a sectional view showing the nozzle.

FIG. 3 is a cross-sectional view showing a connection portion of the mold.

FIG. 4 is a sectional view showing a main part of the injection molding apparatus.

FIG. 5 is a sectional view showing a nozzle structure of a conventional injection molding apparatus.

[Explanation of symbols]

1: injection molding machine, 2: cylinder, 6: nozzle, 7: mold, 8: sprue, 15: nozzle body, 15a: flow path,
15b: threaded portion, 16: nozzle body, 16a: first annular contact surface, 16b: cylindrical convex portion, 16c: second annular contact surface, 1
6d: flow path, 17: connecting portion, 17a: first annular contact surface, 17b: cylindrical concave portion, 17c: second annular contact surface,
A: thermoplastic material, δ: gap.

Claims (3)

[Claims] 1. A tip of a nozzle (6) connected to a tip of a cylinder (2) of an injection molding machine is connected to a connection (1) of a mold (7).
While in contact with 7), the thermoplastic material (A) in the cylinder (2) is injected from the flow paths (15a, 16d) of the nozzle (6) toward the sprue (8) of the mold (7). A nozzle structure of an injection molding apparatus, comprising: a first annular contact surface (16a) substantially perpendicular to a central axis of a nozzle (6); A cylindrical projection (16b) projecting with the central axis aligned and a second annular contact surface (16c) substantially perpendicular to the central axis of the nozzle (6) are formed, and the connecting portion (1) of the mold (7) is formed.
7) a first annular contact surface (17a) substantially orthogonal to the center axis of the sprue (8), a cylindrical concave portion (17b) that matches the center axis with the sprue (8), and a sprue (8) sequentially from the tip end side. ), A second annular contact surface (17c) substantially perpendicular to the center axis of the mold (7) is formed on the second annular contact surface (17c) of the die (7).
c) in contact with the cylindrical projection (16) of the nozzle (6).
b) is inserted into the cylindrical recess (17b) of the mold (7), and the first annular contact surface (16a) of the nozzle (6) faces the first annular contact surface (17a) of the mold (7). And a flow path (15a, 16d) of the nozzle (6) communicates with the sprue (8). 2. The second annular contact surface (16) of the nozzle (6).
c) in contact with the second annular contact surface (17c) of the mold, the first annular contact surface (16a) of the nozzle (6) and the first annular contact surface (17a) of the mold (7). And a gap (δ) defined by the cylindrical concave portion (17b) of the mold (7), and the flow path (15a, 1) is formed in the gap (δ).
6d) and the thermoplastic material (A) flowing through the sprue (8)
Can be filled, and the opening (8a) on the base end side of the sprue (8) is connected to the flow path (15a, 16d) of the nozzle (6).
The nozzle structure of an injection molding apparatus according to claim 1, characterized in that the nozzle structure has a shape that can be connected to the opening (6a) on the front end side without having a step. 3. A nozzle body (15) having a nozzle (6) connected to a tip of a cylinder (2), and a nozzle body (15).
A nozzle body (16) which is screw-connected to the distal end of the nozzle body by a threaded portion (15b). The nozzle body (16) has a first annular contact surface (16a), a cylindrical convex portion (16b) and 3. The nozzle structure for an injection molding apparatus according to claim 1, wherein a second annular contact surface (16c) is formed.