JP2553527Y2 - Injection mold - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a sprue portion formed in a fixed mold so as to be inclined with respect to the mold opening and closing direction, and a runner portion formed between the fixed mold and the movable mold and connected to the sprue portion. The present invention relates to an injection mold having:

[0002]

2. Description of the Related Art FIG. 4 shows a conventional injection molding die.
And a movable mold 2 that can be freely separated. At the right end of the fixed mold 1, there is provided a molten resin injection port 3 to which a molten resin injection nozzle (not shown) is connected. From the molten resin injection port 3, a conical sprue portion 4 diverges toward the left end of the fixed mold 1. Formed. On the mating surface of the fixed mold 1 and the movable mold 2, runner sections 5 and 6 connected to the sprue section 4,
6 are formed with cavity surfaces 8 and 9 connected to each other via a gate 7 formed on the movable mold 2. And, so as to face the tip of the extrusion pin 11 slidably penetrating the movable mold 2,
From the runner part 6 of the movable die 2, a conical sprue lock part 10 is formed so as to expand toward the end.

[0003] The molten resin injected from the molten resin injection port 3 is supplied to a sprue portion 4 formed in the fixed die 1, runner portions 5 and 6 formed between the fixed die 1 and the movable die 2, The product W that flows through the gate portion 7 formed in the mold 2 and flows between the two cavity surfaces 8 and 9 and is connected to the sprue S, the runner R, the sprue lock L, and the gate G is injection-molded.

When the movable mold 2 is separated from the fixed mold 1 in order to take out the injection molded product W from the mold, the sprue lock L is locked in the undercut sprue lock portion 10. Therefore, the runner R and the product W remain on the movable mold 2 side while the sprue S is pulled out from the sprue portion 4 of the fixed mold 1. Subsequently, when the extrusion pin 11 is projected and the sprue lock L is forcibly pushed out from the sprue lock portion 10, the runner R and the product W are separated from the movable mold 2, and at this time, the product W and the runner R is cut off.

[0005]

In general, the molten resin injection port 3 is formed at the center of the fixed mold 1, whereas the sprue lock 10 deviates from the center of the movable mold 2 due to the shape of the product W. , The sprue portion 4 is formed to be inclined by an angle θ with respect to the mold opening and closing direction. As a result, when the movable mold 2 is separated from the fixed mold 1, the sprue S is pushed and bent in the direction of the arrow a, and the connection part b between the sprue S and the runner R that has not yet been cured breaks as shown in FIG. S sometimes remained inside the sprue portion 4 of the fixed mold 1. When the sprue S remains on the fixed mold 1 in this manner, the sprue S needs to be manually taken out, so that the working efficiency is greatly reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an injection mold in which a sprue is prevented from breaking from a connection portion with a runner when the mold is opened.

[0007]

In order to achieve the above object, the present invention provides a sprue portion formed in a fixed mold so as to be inclined with respect to the mold opening and closing direction, and a sprue portion formed between the fixed mold and the movable mold. In the injection molding die having a runner portion connected to the sprue portion, the sprue portion and the runner are provided at one of the acute corners of a pair of corners where the fixed sprue portion and the runner portion intersect. The first feature is that a first groove portion connecting the portions is formed.

According to the present invention, there is provided an injection molding die according to claim 1, wherein a sprue lock portion extending divergently from a runner portion corresponding to the sprue portion is formed in a movable die. A second feature is that a second groove that connects the sprue lock portion and the runner portion at a diagonal position of the first groove portion is formed at one of a pair of corners where the runner portion intersects.

[0009] In addition to the above second feature, the present invention provides:
A third groove and / or a fourth groove may be provided at the other of the pair of corners where the movable sprue lock and the runner intersect and / or at the other of the pair of corners where the fixed sprue and the runner intersect. The third feature is that it is formed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of an injection mold, FIG. 2 is a view showing a state when the mold is opened, and FIG. It is a perspective view of a runner and a sprue.

As shown in FIG. 1, the mold D of the present embodiment is different from the conventional mold shown in FIG. 4 in the shapes near the sprue portion 4, the runner portions 5, 6 and the sprue lock portion 10. Only the other components are the same, and portions corresponding to respective portions of the conventional mold are denoted by the same reference numerals.

The fixed die 1 is formed by a sprue portion 4 formed to be inclined with respect to the opening and closing direction of the mold D, and a runner portion 5 formed on a mating surface of the fixed die 1 with the movable die 2. One of the upper corners of the pair of upper and lower corners, that is, the corner where the sprue part 4 and the runner part 5 form an acute angle, has a triangular shape connecting the sprue part 4 and the runner part 5. together with the first groove portion 12 ₁ is recessed and the other corner portion or sprue portion 4 and the runner portion 5 positioned on the lower side
DOO within the corners form an obtuse angle, a fourth groove 12 ₄ triangular connecting the the sprue portion 4 and the runner portion 5 is recessed.

Of a pair of upper and lower corners formed by a sprue lock portion 10 formed on the movable die 2 and a runner portion 6 formed on the mating surface of the movable die 2 with the fixed die 1, an upper portion is formed. Is formed at one corner of the triangular third connecting the sprue lock 10 and the runner 6.
Groove 12 ₃ with is recessed, to the other corner portion located on the lower side, the second groove portion 12 ₂ triangular connecting the runner portion 6 and the sprue lock portion 10 is recessed.

FIG. 3 shows a sprue S, a runner R, a sprue lock L, and a gate G, excluding the product W, of the molded object formed by the mold D. A pair of upper and lower corners formed by the runner R and sprue S is first groove 12 ₁ and the fourth groove 12 ₄ and the first rib r ₁ triangular formed by the fourth rib r ₄ of the fixed mold 1 while being reinforced is connected in a pair of upper and lower corners formed by the runner R and sprue lock L is first and the second groove portion 12 ₂ of the movable mold 2 triangular formed by the third groove 12 ₃ The second rib r ₂ and the third rib r ₃ are connected and reinforced.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

When the movable mold 2 is separated from the fixed mold 1 by opening the mold D as shown in FIG. 2, the sprue lock L
And the runner R are left behind on the movable mold 2 side, and the sprue S is pulled out from the sprue portion 4 of the fixed mold 1. At this time,
Since the sprue portion 4 is inclined with respect to the opening and closing direction of the mold D, the sprue S is pushed and bent in the direction of arrow a.

As is apparent from FIG. 3, a tensile force acts on the acute angle corner formed by the runner R and the sprue S by the external force in the direction of the arrow a, and the tensile force is applied to the runner R and the sprue S. It is received by the first rib r ₁ connecting S. A compressive force acts on a corner formed by the runner R and the sprue lock L at a diagonal position of the first rib r ₁ , and the compressive force is applied to the runner R
Is the receiving by the second rib r ₂ for connecting the sprue lock L and. At this time, since the ribs r ₁ and r ₂ are thinner than the runner R, the sprue S, and the sprue lock L, the ribs r ₁ and r ₂ are cooled and hardened earlier, and can sufficiently withstand the external force. Most broken easily portion of the way the runner R is reinforced by the first rib r _1, by further action of the first ribs r ₁ is assisted by the second rib r _2, wherein the first rib r ₁ Runner R from near
Is prevented from breaking.

On the other hand, a tensile force acts near the third rib r ₃ connecting the runner R and the sprue lock L, and a compressive force acts near the fourth rib r _{4 at} a diagonal position. As described above, the external force is received by the action of the two ribs r ₃ and r ₄ , and the breakage of the runner R from the vicinity of the third rib r ₃ is prevented.

Thus, the inconvenience that the sprue S is left behind in the sprue portion 4 of the fixed mold 1 due to the breakage of the runner R when the mold is opened can be avoided, and the workability can be improved.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and may be variously modified without departing from the present invention described in the claims for utility model registration. It is possible to make design changes.

For example, in the embodiment, four ribs r ₁ are provided at a portion where the sprue S and the sprue lock L are connected to the runner R.
Is provided with the ~r _4, essential rib is a first rib r ₁ most-effective, other rib r ₂ ~r ₄ may be omitted as appropriate.

[0023]

As described above, according to the first feature of the present invention, the sprue portion and the runner portion are connected to the corner where the fixed sprue portion and the runner portion intersect at an acute angle. Since the first groove portion is formed, even if the sprue is pushed and bent by the action of the inclined sprue portion when the movable mold is separated from the fixed mold, and the tensile force acts on the corner forming the acute angle, the tensile force is reduced. The runner can be prevented from being broken by being received by the rib formed by the first groove. Thereby, the inconvenience that the runner remains in the fixed type runner portion can be avoided, and the work efficiency can be improved.

According to a second feature of the present invention, the second groove is formed at a corner formed by the movable sprue lock and the runner at a diagonal position of the first groove. The rib formed by the second groove portion receives the compressive force acting between the sprue lock and the runner, so that the breakage of the runner can be more reliably prevented.

According to a third feature of the present invention, the breakage of the runner when the mold is opened can be more reliably prevented by the rib formed by the third groove and / or the rib formed by the fourth groove. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of an injection mold according to the present invention.

FIG. 2 is a diagram showing a state when a mold is opened.

FIG. 3 is a perspective view of a runner and a sprue.

FIG. 4 is a diagram showing a state when a conventional mold is opened.

[Explanation of symbols]

1 fixed type 2 movable type 4 sprue part 5 runner part 6 runner part 10 sprue lock part 12 ₁ first groove part 12 ₂ ··· 2nd groove 12 ₃ ··· 3rd groove 12 ₄ ···· 4th groove

Claims (3)

(57) [Scope of request for utility model registration] 1. A sprue portion (4) formed on a fixed die (1) so as to be inclined with respect to a mold opening / closing direction, and the sprue portion formed between a fixed die (1) and a movable die (2). An injection mold having a runner section (5, 6) connected to (4), wherein the sprue section (4) of the fixed mold (1) and the runner section (5) intersect at an acute angle of a pair of corners. At one corner,
An injection molding die having a first groove (12 ₁ ) for connecting the sprue portion (4) and the runner portion (5). 2. The injection mold according to claim 1, wherein a sprue lock portion (10) extending divergently from the runner portion (6) corresponding to the sprue portion (4) is formed on the movable die (2). In one of the pair of corners where the sprue lock section (10) and the runner section (6) of the movable die (2) intersect, the sprue lock section is located at a diagonal position of the first groove section (12 ₁ ). The second groove (1) connecting the (10) and the runner (6).
22. An injection molding mold characterized by forming ₂ ). 3. A sprue lock section (1) of a movable mold (2).
0) and the other of the pair of corners where the runner portion (6) intersects and / or the other of the pair of corners where the sprue portion (4) and the runner portion (5) of the fixed die (1) intersect, a third portion. The injection mold according to claim 2, wherein the groove (12 ₃ ) and / or the fourth groove (12 ₄ ) are formed.