JP3109553B2 - Mold equipment for injection molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die apparatus having a slide core interposed between a fixed die and a movable die.

[0002]

2. Description of the Related Art There are various types of mold devices for injection molding. Among them, there is a system in which a slide core is interposed between both molds in addition to a fixed mold and a movable mold. This type of injection molding die apparatus is a gas hollow molding and foam molding method that separates the presence or absence of a concave part and the presence of a hollow part by molding by operating a slide core while the fixed mold and the movable mold are clamped. And injection molding such as sandwich molding.

For example, when an L-shaped product having a hollow portion 96 (FIG. 8) at the bottom is formed, first, as shown in FIG. 7, an L-shaped product formed by a fixed die 91 and a movable die 92 is formed. The slide core 95 protrudes into the character-shaped cavity 93. Then, while injecting the resin into the cavity 93,
The slide core 95 is retracted, and gas is injected into the molten resin through a nozzle (not shown) while synchronizing with the slide core 95.

As a result, a hollow portion 96 is formed at the bottom of the L-shaped product 960 as shown in FIG. At this time,
The clamping force F by the fixed mold 91 and the movable mold 92 is shown in FIGS.
As shown in (1), it works in parallel with the moving direction of the slide core 95 and does not act on the slide core 95. Therefore, the slide core 95 can easily move forward and backward.

[0005]

However, injection molding using a slide core 95 other than the above-mentioned core back method has the following problems. That is, as shown in FIG. 9, the slide core 95 is moved in the direction (arrow direction) perpendicular to the mold clamping force F, and when the hollow portion is to be formed in the direction perpendicular to the mold clamping force F, the slide core 95 is slid. It is extremely difficult to do so.

This is because a mold clamping force F acts on the slide core 95 between the movable mold 92 and the fixed mold 91. As described above, since the moving direction of the slide core 95 is restricted, there is a problem that the forming process using the slide core 95 has a small degree of freedom and cannot cope with various shapes.

Further, there is a problem that the slide core 95 is easily damaged by the application of the mold clamping force F. The present invention
In view of the above-mentioned conventional problems, the slide core can be freely slid in the direction intersecting with the mold clamping force even in the mold clamping state. An object of the present invention is to provide a mold apparatus for injection molding using a slide core.

[0008]

The present invention relates to an injection molding die apparatus for forming a cavity by using a fixed die, a movable die, and a slide core disposed between the two dies. A core frame attached to either the fixed type or the movable type is provided between the mold and the mold, and the core frame has an insertion hole for slidably disposing the slide core. The slide core is driven by a driving device to move forward and backward in the insertion hole so that the shape of the cavity can be changed, and between the core frame and the fixed mold,
The clearance between the two is formed,
The injection molding die apparatus is characterized in that the core frame has a pressure receiving surface formed in a direction that comes into surface contact with the fixed die and intersects the mold clamping force.

What is most notable in the present invention is that a core frame having an insertion hole through which the slide core can slide is disposed between the fixed mold and the movable mold. And
The slide core is driven by a driving device to move forward and backward in the insertion hole so that the shape of the cavity can be changed.
The core frame is attached to either a fixed type or a movable type.

[0010]

In the injection molding apparatus according to the present invention, the slide core is slidably disposed in the insertion hole of the core frame. Therefore, the mold clamping force F from the fixed mold and the movable mold as in the conventional device is not directly applied to the slide core. Therefore, sliding of the slide core forward and backward is extremely easy, and there is no problem even if the moving direction is a direction perpendicular to the mold clamping force.

Therefore, the degree of freedom of the moving direction of the slide core in the forming process is large, and it is possible to cope with forming various shapes. Also, the slide core is not damaged by the clamping force. As described above, according to the present invention,
For injection molding using slide cores that can slide the slide core freely in the direction that intersects with the mold clamping force while the mold clamping force is acting, and can handle injection molding of various shapes. A mold device can be provided.
Furthermore, as shown in the examples described later,
The acting clamping force is also greatly reduced. In addition,
Due to the horizontal component of the clamping force acting on the surface, the core frame
Burrs that press against the tee.
Wear.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An injection mold apparatus according to an embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIGS. 1 and 2, a fixed mold 11, a movable mold 12,
Injection mold apparatus 1 for forming cavity 15 with slide core 20 disposed between both dies 11 and 12
0.

[0013] Between the fixed mold 11 and the movable mold 12,
A core frame 30 attached to the movable die 12 is provided, and the core frame 30 has an insertion hole 35 through which the slide core 20 can slide. The slide core 20
Is inserted into the through hole 3 by the cylinder which is the driving device 25.
5 is slid forward and backward so that the shape of the cavity 15 can be changed.

Further, between the fixed frame 11 and the core frame 30 facing the core frame 30, the core frame 30 and the fixed frame 11 facing each other face each other in a direction in which the core frame 30 and the fixed frame 11 face each other and cross the mold clamping force. A pressure receiving surface 31 formed in the frame 30 and a clearance 32 in which the two 30 and 11 are separated from each other are formed. In addition,
The pressure receiving surface 31 may be plural, or may be divided into plural. In this case, the combined force of the mold clamping forces acting on the plurality of pressure receiving surfaces 31 acts on the core frame 30.

The clamping force F from the opposed stationary mold 11 against the pressure receiving surface 31 acts in a direction to press the core frame 30 toward the cavity 15 as shown in FIG. The angle θ between the mold clamping force F and the pressure receiving surface 31 is desirably 45 ° or less, and is 22 ° in this example.

Hereinafter, each of them will be described in detail. This example is an example of an injection molding die apparatus for molding a hollow large plate having a size of about 30 × 600 mm. As shown in FIGS. 1 and 2, the injection molding die apparatus 10 of the present embodiment includes a fixed die 11, a movable die 12, a slide core 20, and a core frame 30.

A core frame 30 is provided between the fixed mold 11 and the movable mold 12, and the core frame 30 is slidably mounted on the movable mold 12. The core frame 30 has a body portion 34 (FIG. 4) having an insertion hole 35 through which the slide core 20 can slide forward and backward, and a side plate 33 on which the drive device 25 of the slide core 20 is mounted. ing.

When the mold is closed, the core frame 30 is inserted into the guide hole 341 of the body 34 through the inclined guide pin 13 provided on the fixed mold 11, and the pressure receiving surface 31 on the right side of the body 34 is moved. The cotter 14 disposed to the right of the fixed mold 11
Is in surface contact with the left-side inclined surface 141.

The driving device 2 is provided below the cotter 14.
A tunnel-shaped opening 142 having a lower side opening is formed as a relief for the rod 251 of the hydraulic cylinder which is No. 5. The slide core 20 is slidably disposed in the insertion hole 35 of the core frame 30. The core frame 30
Is a plane parallel to the mold clamping force F, while the pressure receiving surface 31 is a plane intersecting with the mold clamping force F.

On the other hand, as shown in FIG. 5, the slide core 20 has a substantially trapezoidal shape, and as shown in FIG.
It is connected to 51. The rod 251 is disposed so as to be slidable in the insertion hole 35 and the moving direction thereof is parallel to the axis of the rod 251.

The slide core 20 is driven by a driving device 25 to slide forward and backward. The through-hole 21 formed in the slide core 20 for inserting the inclined guide pin 13 has an oval cross section having a large diameter in the left-right direction, so that the slide core 20 can move forward and backward. It does not come into contact with the inclined guide pin 13.

The bottom surface 111 of the fixed die 11, the stepped upper surface 124 and the side surface 122 of the movable die 12, the left end surface 202 and the outer peripheral surface 203 of the slide core 20, the core frame 30
The cavity 15 is formed by the left side surface 301 of the cavity. Reference numeral 121 denotes the upper surface of the movable die 12. When the mold is opened, as shown in FIG.
3, the core frame 30 descends together with the movable mold 12 and separates from the fixed mold 11.

Next, the operation and effect of the injection molding die apparatus of this embodiment will be described. In the injection molding die apparatus 10 of the present embodiment, as shown in FIGS. 1 and 2, the slide core 20 is driven by the driving device 25 to advance and retreat in the insertion hole 35 of the core frame 30 to form the cavity. 15 is changed.
Gas is injected into the molten resin injected in synchronization with the slide core 20 moving backward from the forward state (the state on the left side in FIG. 1) to the right, and the hollow portion 161 as shown in FIG. The hollow molded article 16 having the same is molded.

At this time, the slide core 20 is
, And the slide core 20 does not receive a mold clamping force. Therefore, the movement of the slide core 20 is extremely smooth regardless of the direction of the mold clamping force. Therefore, there is no problem in manufacturing the molded product having the large hollow portion by moving the slide core 20 in the direction perpendicular to the mold clamping force F even in the mold clamped state as in this example.

As described above, the injection molding die apparatus 1 of the present embodiment.
According to 0, there are no restrictions on the direction of movement of the slide core 20, and molded products of various shapes can be obtained. And
Since no excessive force is applied to the slide core 20, breakage such as galling does not occur.

On the other hand, the mold clamping force F acting on the core frame 30 is also greatly reduced. That is, the left side surface 30 of the core frame 30
No. 1 is parallel to the mold clamping force F, so that no mold clamping force acts on the clearance 32 and no mold clamping force acts on the clearance 32. The mold clamping force of the core frame 30 acting on the pressure receiving surface 31 has an angle of θ with respect to the pressure receiving surface 31 as shown in FIG.

Therefore, the acting force Fn acting on the pressure receiving surface 31
Is reduced to sinθ times the mold clamping force F. Since the cross angle θ in this example is 22 °, the Fn is reduced to 37% of the mold clamping force F. Therefore, the strength of the core frame 30 may be relatively small, and the design and manufacture are easy. Since the force Fn for pressing the core frame 30 is sin θ times the mold clamping force F, the crossing angle θ is desirably 45 ° or less.
Decreases to 1 / √2 of the mold clamping force F (about 70% or less).

The acting force F acting on the pressure receiving surface 31
The n horizontal component force Fp (FIG. 6) forms a burr cutting force for pressing the core frame 30 toward the cavity 15. That is,
The burr cutting force Fp presses the vertical burr generating portions 151 and 152 shown in FIGS. 1 and 2 to suppress the vertical burr.

The deburring force Fp is c of the acting force Fn.
os θ times, 0.5 × sin 2θ of the mold clamping force F (Fp = F × sin θ × cos θ = F × 0.5 sin
2θ). Then, by appropriately selecting the intersection angle θ between the mold clamping force F and the pressure receiving surface 31, an appropriate burr cutting force Fp can be obtained.

Since the deburring force Fp shows the maximum value (sin2θ = 1) when the cross angle θ is 45 °, the cross angle θ is preferably 45 ° or less. As described above, according to the present embodiment, the slide core 20 can be freely slid in the direction crossing the mold clamping force F, and can cope with various shapes of injection molding.
Can be provided.

In this embodiment, an example of a hollow molded product is shown.
The present invention can be applied to injection molding such as so-called "sandwich molding" or "foam molding" in which another material is injected instead of injecting a gas. Also, the present invention can be applied to so-called "injection compression molding" in which the direction of movement of the slide core is opposite to that in the present example and the molded product is gradually compressed from a thick state.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an injection molding die apparatus according to an embodiment.

FIG. 2 is a sectional view of the apparatus of FIG. 1 in which a slide core is retracted during injection blow molding.

FIG. 3 is a sectional view of the apparatus of FIG. 1 at the time of release.

FIG. 4 is a perspective view of a body of the core frame according to the embodiment.

FIG. 5 is a perspective view of a slide core according to the embodiment.

FIG. 6 is an explanatory diagram of a mold clamping force acting on a pressure receiving surface in the injection molding die apparatus of the embodiment.

FIG. 7 is an explanatory view of a conventional injection molding die apparatus with a slide core.

FIG. 8 is an explanatory diagram when the slide core is retracted in FIG. 7;

FIG. 9 is another explanatory view of a conventional injection mold device with a slide core.

[Explanation of symbols]

 10. . . 10. Molding apparatus for injection molding, . . Fixed type, 12. . . Movable type, 15. . . Cavity, 20. . . Slide core, 25. . . Drive device, 30. . . Core frame, 31. . . Pressure-receiving surface, 32. . . Clearance, 35. . . Insertion hole,

Claims (1)

(57) [Claims] 1. An injection molding apparatus for forming a cavity by using a fixed mold, a movable mold, and a slide core disposed between the molds, wherein the mold is provided between the fixed mold and the movable mold. Is provided with a core frame attached to either a fixed type or a movable type, and the core frame has an insertion hole for slidably disposing the slide core. The cavity is driven by a driving device to move forward and backward in the insertion hole to change the shape of the cavity, and a clearance is formed between the core frame and the fixed mold so as to be separated from each other. In addition, the core frame has a pressure receiving surface formed in a direction that makes surface contact with the fixed die and crosses the mold clamping force.