JP2002273767A - Injection-molding apparatus and injection-molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection-molding apparatus capable of restraining generation of a flash due to abrasion of an injecting nozzle and a sprue bush and preventing an injection trouble due to solidification of a molten resin in the injecting nozzle. SOLUTION: A guide insertion concave portion 19 and a nozzle insertion hole 22 are mounted in a sprue bush main body 17 and a sprue bush guide 18 is removably attachably housed in the guide insertion concave portion 19. A guide 18a is mounted in the sprue bush guide 18 to guide a nozzle tip portion 13 of the injecting nozzle 11 such that a nozzle insertion portion 14 of the injecting nozzle 11 is inserted into the nozzle hole 22 when the injecting nozzle 11 is inserted in the sprue bush member 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection molding apparatus and an injection molding method.

[0002]

2. Description of the Related Art In general, an injection molding apparatus is used to mold a product having a predetermined shape from a thermoplastic material.
Among the injection molding apparatuses, there is a direct nozzle type. FIG. 5 shows a direct nozzle type injection molding apparatus and its molding process. The flow of the molding process using the injection molding apparatus 50 will be described. First, as shown in FIG. 5A, an upper mold 52 as a movable mold having an injection port 51 is provided.
To a lower mold 53 as a fixed mold. Next, as shown in FIG. 5B, a nozzle touch step of moving the injection nozzle 54 toward the upper die 52 so as to insert the insertion portion 55 of the injection nozzle 54 into the injection inlet 51 of the upper die 52 is performed. . Next, as shown in FIG. 5C, a molten thermoplastic material (molten fluid) is injected from the injection nozzle 54 into a space (cavity) formed by the upper mold 52 and the lower mold 53. Then, an injection / holding step of maintaining the pressure until the molten fluid solidifies is performed. Finally, as shown in FIG. 5D, after the molten fluid has solidified, the injection nozzle 54 is separated from the upper mold 52,
A mold opening process of separating the upper mold 52 from the lower mold 53 is performed. Then, the upper mold 5 is formed by the above four molding steps.
A product S having a predetermined shape is formed in a space (cavity) formed by the lower mold 2 and the lower mold 53.

In this case, in the injection / pressure keeping step, in order to prevent the molten fluid from overflowing from the injection port 51 to the outside of the mold, the outer peripheral surface of the insertion portion 55 of the injection nozzle 54 and the inner peripheral surface of the injection port 51 are required. Need to be perfectly matched.
That is, it is necessary to match (center) the axis of the injection nozzle 54 with the axis of the injection inlet 51.

Therefore, in general, the injection nozzle 54 is centered with respect to the injection port 51 by a centering mechanism (not shown), and then the insertion portion 55 is inserted into the injection port 51. ing.

As shown in FIG. 6, an injection port 51 of a conventional injection molding apparatus 50 is provided in a spool bush member 56 of an upper die 52. The spool bush member 56 is provided with a tapered portion 57 that expands outward (upward in FIG. 6) from the injection inlet 51. As shown in FIG. 7, when the insertion portion 55 of the injection nozzle 54 is inserted into the injection inlet 51, the tapered portion 57
, The tapered tip surface 54a of the injection nozzle 54 comes into contact.

[0006]

However, when the ejection nozzle 54 is misaligned due to the centering mechanism accuracy or the like, as shown in FIG. 8, the insertion portion 55 of the ejection nozzle 54 Before being inserted into the injection port 51, the tip thereof comes into contact with the tapered portion 57. The contact between the injection nozzle 54 and the spool bush member 56 is determined by the contact between the injection nozzle 54 and the spool bush member 56.
Causes wear. In particular, as shown in FIG. 8, when the boundary portion 57a between the tapered portion 57 and the injection port 51 is worn, there is a problem that the molten fluid overflows out of the mold and burrs are generated on the product S. In addition, when the injection nozzle 54 and the spool bush member 56 are worn out, replacement of the injection nozzle 54 and the spool bush member 56 is frequently required, which is not only complicated but also uneconomical. became.

An object of the present invention is to provide an injection molding apparatus and an injection molding method capable of suppressing the occurrence of burrs due to wear of an injection nozzle and a spool bush member.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to the first aspect is directed to an injection nozzle for injecting a fluid of a thermoplastic material, and receiving the injected fluid of the thermoplastic material. A lower mold to be solidified into a predetermined shape, and an upper part of the lower mold, which is disposed so as to be vertically movable with respect to the lower mold, and between the lower mold at the time of injection of a fluid of a thermoplastic material by the injection nozzle. In the injection molding apparatus having an interposed spool bush member, the spool bush member is detachably housed in the guide housing portion and a spool bush body provided with a guide housing portion and a nozzle insertion hole, and the nozzle of the injection nozzle And a spool bush guide provided with a guide portion for guiding a nozzle tip of the injection nozzle so as to insert the insertion portion into the nozzle insertion hole. That.

According to a second aspect of the present invention, in the injection molding apparatus according to the first aspect, the nozzle tip of the injection nozzle is inserted into the nozzle insertion hole before the nozzle insertion portion is inserted into the nozzle insertion hole. The gist of the invention is to provide a nozzle-side guide portion guided by the guide portion of the spool bush guide so that the center axes of the injection nozzle and the spool bush member are aligned.

[0010] The invention described in claim 3 is the invention according to claim 1 or 2.
Wherein the guide portion of the spool bush guide is provided with a plurality of notches.

According to a fourth aspect of the present invention, there is provided an injection nozzle provided with a nozzle insertion portion for injecting a fluid of a thermoplastic material, and a lower die for receiving the injected fluid of the thermoplastic material and solidifying it into a predetermined shape. A spool bush main body provided with a guide housing portion and a nozzle insertion hole, and a spool bush guide removably housed in the guide housing portion and guiding the injection nozzle, wherein the lower die is provided on the upper portion of the lower die. On the other hand, a fluid of a thermoplastic material is injection-molded by an injection molding apparatus having a spool bush member interposed between the lower mold and the thermoplastic resin when the fluid of the thermoplastic material is injected by the injection nozzle. In the injection molding method, the spool bush guide, when the injection nozzle is inserted into the spool bush member,
The gist is that the nozzle insertion part guides the injection nozzle so as to be inserted into the nozzle insertion hole.

According to a fifth aspect of the present invention, in the injection molding method according to the fourth aspect, the injection nozzle is guided by the spool bush guide so that the center axis of the injection nozzle and the spool bush member are aligned. The gist is that the nozzle insertion portion is inserted into the nozzle insertion hole.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the above-mentioned injection molding method, the gist is that the fluid of the thermoplastic material is a molten resin. The invention according to claim 7 is the injection molding method according to claim 4 or 5,
The gist is that the fluid of the thermoplastic material is a molten metal.

(Operation) According to the first, fourth, sixth and seventh aspects of the present invention, when the injection nozzle is inserted (touched) into the spool bush member, the spool bush is detachably housed in the spool bush body. Since the guide is guided by the guide, the spool bush guide is worn instead of the spool bush body. Therefore, by easily replacing the spool bush guide, the uneconomic problem caused by the replacement of the spool bush member is solved as compared with the related art.

According to the second and fifth to seventh aspects of the present invention, the wear of the nozzle insertion portion and the edge of the nozzle insertion hole is prevented, and burrs are generated on the product due to the wear of the edge of the nozzle insertion hole. Can be suppressed.

According to the third aspect of the present invention, the first aspect is provided.
In addition to the effects of the inventions described in (2) and (3), the contact area between the injection nozzle and the spool bush member can be reduced.
As a result, the reduction in the contact area and the increase in the contact area between the injection nozzle and the spool bush member due to the structural change of the spool bush cancel each other, so that the injection due to the temperature drop of the injection nozzle due to the increase in the contact area between the two. Failure can be prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In addition, the injection molding apparatus of the present embodiment is characterized by an injection nozzle and a spool bush member on the upper mold side as compared with the conventional injection molding apparatus 50, and therefore, for convenience of explanation, the description on the lower mold side is omitted. The structure of the injection nozzle and the spool bush member will be described in detail.

As shown in FIGS. 1 and 2, the injection nozzle 11 of the injection molding apparatus 10 of the present embodiment
A nozzle tip 13 extending from one end (lower end in FIGS. 1 and 2) of an end face 12a of the nozzle body 12, and a nozzle insertion portion 14 projecting from the center of the tip face 13a of the nozzle tip 13. Have.

The nozzle tip 13 has a cylindrical portion 13b.
And a frustoconical portion 13c as a nozzle-side guide portion. The nozzle insertion portion 14 is formed in a truncated conical shape in which the outer diameter decreases as the distance from the nozzle tip portion 13 increases.

In the injection nozzle 11, a through-hole 15 having the central axis of the injection nozzle 11 as an axis and penetrating the nozzle body 12, the nozzle tip 13, and the nozzle insertion portion 14.
Is provided. The through hole 15 is formed as a flow path through which a resin (molten resin) as a thermoplastic material in a molten state flows.

The spool bush member 16 of the injection molding apparatus 10 of the present embodiment includes a spool bush body 17.
And a spool bush guide 18. The spool bush body 17 includes a large diameter portion 17a and a small diameter portion 17a.
b. The large-diameter portion 17a is provided with a guide fitting recess 19 as a guide accommodating portion, and a truncated conical recess 20 is provided from the bottom center of the guide fitting recess 19. The small-diameter portion 17b is provided with a cylindrical recess 21 communicating with a cavity (not shown), and a nozzle insertion hole 22 communicating from the bottom center of the cylindrical recess 21 with the truncated conical recess 20 is provided. ing. The nozzle insertion hole 22 is formed in a truncated conical shape such that the inner diameter decreases as the nozzle insertion portion 14 approaches the cylindrical recess 21 at the same conicity as the nozzle insertion portion 14.

The spool bush guide 18 is shown in FIG.
As shown in FIG. 2, the guide fitting concave portion 19 is formed in an annular shape with the same axial thickness. The outer diameter of the spool bush guide 18 is the guide fitting recess 19.
Equal to the inner diameter of the inner hole (that is, the diameter of the inner hole 18a).
Is set substantially equal to the outer diameter of the cylindrical portion 13b of the nozzle tip 13. As shown in FIG. 3, a plurality of (in this embodiment, eight) notches 18 b are provided at equal angular intervals on the circumference of the inner hole 18 a of the spool bush guide 18.

In this embodiment, the spool bush member 1
Reference numeral 6 denotes a configuration in which the spool bush guide 18 is detachably fitted into the guide fitting recess 19 of the spool bush body 17. As shown in FIG. 4, the distance H from the upper surface of the spool bush member 16 fitted to the spool bush body 17 to the bottom surface 20a of the truncated conical recess 20 is equal to the boundary between the cylindrical portion 13b and the truncated conical portion 13c. The distance is set to be greater than the distance h from the line to the tip of the nozzle insertion portion 14.

When injection molding is performed by such an injection molding apparatus 10, in the nozzle touching step,
The centered injection nozzle 11 is inserted into the spool bush member 16. As shown in FIG. 1, the injection nozzle 11 inserted into the spool bush member 16 has the nozzle insertion portion 14 abutting against the nozzle insertion hole 22 and the injection nozzle 11 being in contact with the frustoconical recess 20.
, And the main body end surface 12 a comes into contact with the upper surface of the spool bush guide 18. At this time, when there is no misalignment, the injection nozzle 11 is mounted on the spool bush guide 1 by the cylindrical portion 13b of the nozzle tip portion 13.
8 is inserted into the spool bush member 16 in a straight line while passing through the inner hole 18a.

On the other hand, if there is any misalignment,
As shown in FIG. 4, the injection nozzle 11 has a frusto-conical portion 13 c of the nozzle tip 13 in contact with an upper end edge of an inner hole 18 a of the spool bush guide 18, and is guided by the inner hole 18 a into the spool bush member 16. Is inserted into. At this time, since the distance H from the upper surface of the spool bush member 16 to the bottom surface 20a is set to be larger than the distance h from the boundary between the cylindrical portion 13b and the truncated cone portion 13c to the tip of the nozzle insertion portion 14, the cylindrical portion Before the nozzle 13b is inserted into the inner hole 18a, the nozzle insertion part 14 does not contact the bottom surface 20a. Since the diameter of the inner hole 18a is set substantially equal to the outer diameter of the cylindrical portion 13b of the nozzle tip portion 13, the cylindrical portion 13b is
When it is inserted into the nozzle, the misalignment of the injection nozzle 11 is corrected, and the nozzle insertion portion 14 is inserted into the nozzle insertion hole 22 without contacting the bottom surface 20a.

According to the injection molding apparatus 10 of the above embodiment, the following features can be obtained. (1) In the above embodiment, the spool bush member 16
Has a spool bush body 17 and a spool bush guide 18. In the spool bush body 17,
A guide fitting recess 19 and a nozzle insertion hole 22 are provided, and the spool bush guide 18 is
In the guide fitting concave portion 19. In addition, the spool bush guide 18 has the injection nozzle 11
When the nozzle is inserted into the spool bush member 16, the nozzle insertion portion 14 of the injection nozzle 11 is
A guide portion 18a for guiding the nozzle tip portion 13 of the injection nozzle 11 so as to be inserted into the inside is provided.

Accordingly, in the nozzle touching step in the molding step of the injection molding apparatus 10, when the centering of the injection nozzle 11 is misaligned, the injection nozzle 11 comes into contact with the spool bush guide 18, so that the spool bushing body 17
Instead, the spool bush guide 18 is worn.
Therefore, by easily replacing the spool bush guide 18, it is possible to prevent an increase in cost due to the replacement of the spool bush member 16 as compared with the related art.

(2) In the present embodiment, as described in detail above, before the injection nozzle 11 is inserted into the nozzle insertion hole 22 of the injection nozzle 11, the injection nozzle 11 and the spool bush member 16 Are guided by the spool bush guide 18 so that the center axis of the spool bushing coincides with the center axis.

Accordingly, the edge of the nozzle insertion portion 14 and the edge of the nozzle insertion hole 22 (that is, the upper edge and the bottom surface 20 of the nozzle insertion hole 22).
(a boundary portion a) can be prevented, and the occurrence of burrs on the product due to the wear of the edge of the nozzle insertion hole 22 can be suppressed.

(3) In this embodiment, eight notches 18b are provided in the inner hole 18a of the spool bush guide 18. Therefore, the contact area between the injection nozzle 11 and the spool bush member 16 can be reduced.
This can be offset by an increase in the contact area between the spool bush member 1 and the spool bush member 16 due to a structural change. As a result, heat radiation on the injection nozzle 11 side, which is proportional to the contact area, is reduced,
Solidification of the molten resin in the injection nozzle 11 due to a temperature drop of the injection nozzle 11 due to intense heat radiation on the side of the injection nozzle 11 can be suppressed. Therefore, injection failure of the injection molding apparatus 10 due to solidification of the molten resin in the injection nozzle 11 can be prevented.

The above embodiment may be modified as follows. The notch 18b may be formed in other shapes, and the number of the notch 18b may be plural other than eight.

The inner hole 18 of the spool bush guide 18
The notch a may be provided at the nozzle tip 13 of the injection nozzle 11. In order to reduce the heat radiation, a heat insulating material or the like may be attached to the inner hole 18a of the spool bush guide 18 or the nozzle tip 13 of the injection nozzle 11 instead of providing the cutout.

The thermoplastic material is not limited to a resin, but may be a metal (for example, magnesium, aluminum, zinc, or an alloy thereof). Next, technical ideas other than the inventions described in the claims that can be understood from the above embodiment and other examples will be described below together with their effects.

(1) In the injection molding apparatus according to claim 1, a nozzle tip (13) of the injection nozzle (11).
In a state where the nozzle insertion portion (14) is not in contact with the spool bush member (16), the spool bush guide (so that the center axis of the injection nozzle (11) and the spool bush member (16) are aligned with each other. 18)
An injection molding apparatus provided with a nozzle-side guide portion (13c) guided by a guide portion (18a).

(2) The injection molding apparatus according to any one of claims 1 to 3, wherein the fluid of the thermoplastic material is a molten resin. (3) The injection molding apparatus according to any one of claims 1 to 3, wherein the fluid of the thermoplastic material is a molten metal.

[0036]

As described in detail above, according to the first to seventh aspects of the present invention, it is possible to suppress the occurrence of burrs due to wear of the injection nozzle and the spool bush member.

According to the third aspect of the present invention, injection failure due to solidification of the molten fluid in the injection nozzle can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an injection molding apparatus according to an embodiment.

FIG. 2 is an exploded sectional view of a main part of the injection molding apparatus.

FIG. 3 is a plan view of a spool bush guide constituting a spool bush member of the injection molding apparatus.

FIG. 4 is an explanatory view illustrating a molding step of the injection molding apparatus.

FIG. 5 is an explanatory diagram illustrating a flow of a molding process of the injection molding apparatus.

FIG. 6 is a sectional view of a main part of a conventional injection molding apparatus.

FIG. 7 is an explanatory view illustrating a molding process of a conventional injection molding apparatus.

FIG. 8 is an explanatory view for explaining a molding process of a conventional injection molding apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Injection molding apparatus, 11 ... Injection nozzle, 13 ... Nozzle tip part, 13c ... Frustoconical part as nozzle side guide part, 14 ... Nozzle insertion part, 16 ... Spool bush member, 17 ... Spool bush body, 18 ... Spool Bush guide, 18a: Guide portion, 18b: Notch, 1
9: guide fitting recess as a guide receiving portion, 22: nozzle insertion hole.

Claims (7)

[Claims] 1. An injection nozzle (11) for injecting a fluid of a thermoplastic material, a lower mold for receiving the injected fluid of the thermoplastic material and solidifying it into a predetermined shape, and A spool bush member (16) interposed between the lower die and the injection nozzle (11) when the injection nozzle (11) injects a fluid of a thermoplastic material, the injection molding device comprising: The spool bush member (16) is detachably housed in a spool bush body (17) provided with a guide housing portion (19) and a nozzle insertion hole (22), and the guide housing portion (19). The injection nozzle (1) is inserted so that the nozzle insertion portion (14) of (11) is inserted into the nozzle insertion hole (22).
A guide section (18) for guiding the nozzle tip section (13) of 1).
a) a spool bush guide (18) provided with (a). 2. The injection molding apparatus according to claim 1, wherein a nozzle tip (13) of the injection nozzle (11) has
The nozzle insertion part (14) is provided with the nozzle insertion hole (22).
Before being inserted into the inside, the guide portion (18) of the spool bush guide (18) is adjusted so that the center axis of the injection nozzle (11) and the spool bush member (16) are aligned.
An injection molding apparatus comprising a nozzle-side guide portion (13c) guided by a). 3. The injection molding apparatus according to claim 1, wherein a guide portion (18) of the spool bush guide (18) is provided.
An injection molding apparatus, wherein a) is provided with a plurality of notches (18b). 4. An injection nozzle (11) provided with a nozzle insertion portion (14) for injecting a fluid of a thermoplastic material, and a lower die for receiving the injected fluid of the thermoplastic material and solidifying it into a predetermined shape. A spool bushing body (17) provided with a guide accommodating portion (19) and a nozzle insertion hole (22); and a detachably accommodated in the guide accommodating portion (19).
1) a spool bush guide (18) for guiding the same, which is disposed above the lower die so as to be movable in the vertical direction with respect to the lower die, and which is used when the injection nozzle (11) injects a fluid of a thermoplastic material. An injection molding method for injection-molding a fluid of a thermoplastic material using an injection molding apparatus having a spool bush member (16) interposed between a lower die and the spool bush guide (18). When the (11) is inserted into the spool bush member (16), the injection nozzle (1) is inserted so that the nozzle insertion portion (14) is inserted into the nozzle insertion hole (22).
An injection molding method characterized in that 1) is guided. 5. The injection molding method according to claim 4, wherein the injection nozzle (11) and the spool bush member (1) are provided.
6) so that the center axis is aligned with the injection nozzle (1).
An injection molding method, wherein 1) is guided by the spool bush guide (18), and the nozzle insertion portion (14) is inserted into the nozzle insertion hole (22). 6. The injection molding method according to claim 4, wherein the fluid of the thermoplastic material is a molten resin. 7. The injection molding method according to claim 4, wherein the fluid of the thermoplastic material is a molten metal.