JPH07256705A - Injection mold - Google Patents

Abstract

PURPOSE:To prevent a molded article from being drawn toward a cavity side mold when the molded article is released from the mold, enable the molded article to be reliably held by a cored mold, prevent the resin-molded article from being deformed and broken and obtain good releasability in the mold for injection molding for forming a resin-molded article, particularly a molded article containing many recesses and protrusions. CONSTITUTION:In a mold for injection molding wherein grooves 35 are provided in a retainer plate in order to form a resin-molded article, small projections 46 are provided on a in core 45 correspondence to the grooves 35 of the retainer plate 32. By making a shrinkage force of resin after molding act on the small projections 46 of the core 45, the resin-molded article is allowed to be surely held by the core 45 to prevent reliably the resin-molded article from being transferred to a cavity side, whereby the resin-molded article is prevented from being deformed and broken, and releasing operation is smoothly carried out.

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 for preventing deformation and damage of a molding when the injection molding is opened.

[0002]

2. Description of the Related Art FIG. 12 is a cross-sectional view showing the structure of a door pocket installed below the surface of a door trim or the like. The door pocket 1 is made of a synthetic resin injection molding and constitutes a speaker grill. A plurality of louvers 2 are provided.

As shown in FIG. 13, the structure of the injection molding die for molding the door pocket 1 is such that the cavity mold 3 on the fixed side and the cavity mold 3 can be contacted and separated from each other. And a movable core die 4, and a molten resin is injected and filled into a cavity formed between the cavity die 3 and the core die 4 to form a door pocket 1 having a shape shown in FIG. To be done.

When the molding of the door pocket 1 is completed, the core mold 4 moves, the door pocket 1 is separated from the cavity mold 3 together with the core mold 4, and the door pocket 1 is removed from the core mold 4 by an ejector pin (not shown). Although a molded product is obtained by releasing the mold, when the groove 5 is set adjacent to the cavity mold 3 as in the louver 2 of the door pocket 1 due to the shrinkage of the resin after molding, as shown in FIG.
As shown in FIG. 4, the resin shrinkage of the molded body causes a force in the direction of the arrow from each louver 2 to act on the cavity mold 3, so that the louver 2 fits into the groove portion 5 and the door pocket 1 is inserted into the cavity mold 3. It has been pointed out that the door pocket 1 is deformed when the mold is opened, or is damaged in an extreme case when the mold is opened.

In order to smoothly remove the louver 2 from the cavity mold 3, although not shown, when a recess is formed in the core mold 4, the louver 2 is contracted by a resin contracting action.
Adheres to the core mold 4 and can prevent contact with the cavity mold 3, but since a convex portion is formed on the back surface of the product, for example, a backing sheet for blindfolding cannot be attached, and Problems such as interference of

When a textured pattern or the like is engraved on the surface of the product, there is a problem that the frictional force between the surface of the product and the mold surface of the cavity mold 3 causes a defective appearance such as whitening of the textured pattern. .

The present invention has been made in view of the above circumstances, and in an injection molding die for a resin molded body, the molded body does not remain in the cavity mold when the mold is opened, and is reliably held in the core mold. It is an object of the present invention to provide an injection-molding die that is capable of smoothly performing a mold releasing operation.

[0008]

To achieve the above object, the present invention comprises a cavity mold having a fixed mold plate having a predetermined mold surface shape, and a core having a predetermined mold surface shape. Resin having a ridge by a groove formed in the fixed side mold plate by injecting and filling molten resin into a cavity formed between the fixed side mold plate and the core. In an injection molding die for molding a molded body into a required shape, a small protrusion is formed on the core in correspondence with a groove portion formed on the fixed-side mold plate.

Further, the groove portion formed in the fixed side mold plate of the cavity side mold is characterized in that a plurality of grooves are formed in parallel or in a grid pattern.

[0010]

As apparent from the above structure, the small protrusions provided on the core cause the shrinkage force of the resin molding to act in the direction of holding the small protrusions at the time of mold release, so that the molded body is securely held by the core, It is not attracted to the cavity mold, and the molded body is not deformed or damaged.

Further, since the compact is securely held on the core by the small protrusions provided on the core, the mold and the cavity mold can be smoothly released from each other, and continuous production is possible.

Further, when the core is provided with small protrusions, a recess is formed in the resin molded body. Therefore, when a cloth sheet such as a non-woven fabric is attached to the surface formed by the core, there is no obstacle.

[0013]

Embodiments of the injection molding die according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an external view of a door pocket molded by using the injection molding die according to the present invention, FIG. 2 is a sectional view of the door pocket, and FIG. 3 is an overall structure of the injection molding die according to the present invention. FIG. 4 is a cross-sectional view showing the main structure of the injection mold according to the present invention, FIG. 5 is a plan view of the core mold,
FIG. 6 is an explanatory view showing the operation of the injection molding die according to the present invention.

Further, FIGS. 7 to 9 are cross-sectional views showing a main part of a core mold in an injection molding mold according to the present invention,
FIG. 10 is a perspective view showing a resin molded body manufactured by the injection molding die according to the present invention, and FIG. 11 is a sectional view of a main part showing a molding die for molding the injection molding body shown in FIG.

In FIGS. 1 and 2, reference numeral 10 denotes an automobile door trim that is installed inside the automobile. The automobile door trim 10 is formed into a required shape, and has shape retention and mounting rigidity to a door inner panel. Core material 1
1 and a skin material 12 which is attached to the surface of the core material 11 and imparts decorativeness and cushioning properties,
A door pocket 20 made of a resin molded body is mounted below the surface of the door trim 10.

In this embodiment, the door pocket 20 is formed into a required shape by injection-molding polypropylene resin, and a speaker grill 21 is partially formed on the door pocket 20. The speaker grill 21 includes a plurality of louvers. 22 are arranged in parallel in the lateral direction.

To attach the door pocket 20 to the door trim 10, a screw 24 is screwed from the rear side of the door trim 10 to the mounting boss 23 projectingly formed on the rear side of the door pocket 20. Door pocket 20
Is attached to a predetermined position of the door trim 10.

By the way, in the door pocket 20, each louver 22 constituting the speaker grill 21 has a recess 25 formed on the back surface of each louver, as shown in an enlarged view in FIG. It is a secondary component of the structure of the injection molding die according to the present invention, and does not hinder the application of the backing sheet for blindfolds.

Next, the structure of the injection molding die for molding the door pocket 20 will be described with reference to FIG.
The main configuration will be described below.

First, as shown in FIG. 3, the injection mold according to the present invention comprises a cavity mold 30 on the fixed side,
It is roughly composed of a movable core die 40,
More specifically, in the cavity mold 30, a fixed side mold plate 32 having a predetermined mold surface shape is attached to a fixed side attachment plate 31 so as to form a product shape, and a locate ring 33 and a sprue bush 34 are provided. The cavity resin 3 is provided with molten resin supplied from an injection molding machine (not shown).
Injection filling is performed between 0 and the core mold 40.

On the other hand, the core mold 40 has a movable side mounting plate 41.
A movable side mold plate 44 is attached to the movable side mold plate 44 via a spacer block 42 and a receiving plate 43, and a core 45 for forming a product shape is attached to the movable side mold plate 44.

The shape of the door pocket 20 is determined by the fixed-side mold plate 32 of the cavity mold 30.
And the shape of the cavity formed between the core 45 and the core 45 of the core-side mold 40.

By the way, according to the present invention, after molding, the molded product can be securely held in the core mold 40 and is not attracted to the cavity mold 30 side, so that the mold releasability of the molded product is improved, and The feature is that deformation and damage of the molded body are prevented in advance.

For example, as shown in FIG. 4, the mold surface shapes of the fixed side mold plate 32 of the cavity mold 30 and the core 45 of the core mold 40 are shown in the vicinity of the speaker grill 21 in the door pocket 20 as shown in the figure. The mold configuration will be described. A plurality of groove portions 35 for forming the plurality of louvers 22 of the speaker grill 21 are provided in the fixed-side template 32 at predetermined intervals. 45 is a small protrusion (a cylindrical protrusion shown in FIG. 5) 4
6 is formed.

Ejector pins 50 are arranged alternately with the small protrusions 46.

Therefore, during injection molding, the fixed side mold plate 32
The core 45 and the core 45 are joined together along the parting line, the molten resin is injected and filled into the cavity formed between the two, and the speaker grill 2 in the door pocket 20.
1 is molded, but after molding, the core mold 40 moves away from the cavity mold 30, and at this time, as shown in FIG. 6, in each louver 22, resin is applied so as to sandwich the small protrusion 46. Of the resin molded body, the door pocket 20 is firmly joined to the core 45 and is not attracted to the fixed mold plate 32 side of the cavity mold 30.

The size of the small projection 46 is as follows.
The height h1 of 6 is h when the thickness of the louver 22 is h.
The range of 1 = 0.2h to 0.8h is preferable.

Further, the width d1 of the small protrusion 46 is determined by the louver 2
When the width d is set to be 2, if d1 = 0.3d to 0.5d is set, the core 45 of the core mold 40 and the door pocket 20 which is an injection molded body, particularly the speaker grill 21 portion, are formed. Good adhesion can be obtained, and when the mold is opened, the speaker grill 21 portion is not drawn to the cavity mold 30 side, which causes deformation and damage, and the surface of the door pocket 20 has a grain pattern. When engraved on the mold surface of the fixed-side mold plate 32, the grain pattern does not rub and whiten.

In addition, since the releasing operation proceeds smoothly, there is an advantage that continuous production is possible and productivity is improved.

Further, the speaker grill 21 portion of the door pocket 20 is not formed with a projection on the back surface, but only has a recess 25 corresponding to the small projection 46, and a backing sheet for blindfold such as a cloth sheet is attached. It does not hinder the operation and does not interfere with other parts such as the speaker.

Although not shown, the small protrusion 46 may have a cylindrical pin shape as shown in FIG. 5, but may be provided integrally with the core 45 as a protrusion along the longitudinal direction of the louver 22. In that case. The notch may be provided in the ridge, and the ejector pin 50 may be set in the notch.

As described above, according to the present invention, the small protrusions 46 are provided on the core 45 so as to correspond to the groove portions 35 formed on the fixed-side mold plate 30, and the small protrusions 46 of the core 45 are caused by the contracting action of the resin molding. Apply the shrinkage force of the resin so that it is sandwiched from both sides,
The resin molded body is firmly adhered to the core 45 to promote the releasability between the resin molded body and the fixed mold plate 32 of the cavity mold. As a modified example, it is possible to set the shape as shown in FIGS. 7 to 9.

That is, as shown in FIG.
By setting the draft taper 47 on the side surface of the core die 40
There is an advantage that the demolding operation can be easily performed when demolding the resin molded body held by (1) by the ejector means.

On the contrary, as shown in FIG. 8, if a reverse draft taper 48 is set on the side surface of the small protrusion 46, the adhesion between the core 45 of the core mold 40 and the door pocket 20 which is a resin molded body. Can be further strengthened.

Similarly, as shown in FIG. 9, if a grain pattern 49 is formed on the side surface of the small protrusion 46, the frictional force between the side surface of the small protrusion 46 and the resin molding increases, Synergistically with the contraction action of the resin, the adhesion between the core 45 and the door pocket 20 in the core mold 40 is improved.

Each of the embodiments described above is equivalent to the door pocket 2
Although the speaker grille 21 setting portion in No. 0 has been described, as shown in FIG. 10, in the case where the flange 61 is formed even in the resin molded body 60 in which the louver 22 is not set, this molding die for injection molding is As shown in FIG. 11, if the groove portion 35 for forming the flange 61 is formed in the fixed side mold plate 32 and the small protrusion 46 is set in the core 45, the resin molded body 60 is drawn toward the cavity mold 30 side. Has the same effect that good mold releasability is obtained, deformation and damage do not occur, and good mold release operability is obtained. The injection molding die according to the present invention is a resin molded product. Generally applicable.

[0038]

As described above, according to the present invention, the following operational effects are achieved.

(1) The shrinkage force of the resin molded body acts on the small protrusions provided on the core mold surface of the core mold, and the resin molded body is securely held by the core at the time of mold release. Since the resin molded body is not attracted to the mold, deformation or damage of the resin molded body due to mold opening can be reliably prevented, moldability can be improved, and the defect rate can be significantly reduced.

(2) The small protrusions provided on the die surface of the core die allows the resin molding to be held securely on the core and is not attracted to the cavity die side. Therefore, continuous operation is possible without interrupting the operation, and the productivity can be remarkably enhanced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a door trim equipped with a door pocket manufactured by an injection molding die according to the present invention.

FIG. 2 is a sectional view showing the structure of the door pocket shown in FIG.

FIG. 3 is an overall view showing a first embodiment of an injection molding die according to the present invention.

FIG. 4 is a cross-sectional view of an essential part of the injection molding die shown in FIG.

5 is a view on arrow A in FIG.

FIG. 6 is a sectional view showing a state at the time of releasing the injection molding die according to the present invention.

FIG. 7 is a cross-sectional view of essential parts showing a modified example of the core mold in the injection molding mold according to the present invention.

FIG. 8 is a sectional view of an essential part showing a modified example of the core mold in the injection mold according to the present invention.

FIG. 9 is a sectional view of an essential part showing a modified example of the core mold in the injection mold according to the present invention.

FIG. 10 is a perspective view showing a resin molded body.

11 is a cross-sectional view showing an injection molding die used for molding the resin molded body shown in FIG.

FIG. 12 is a sectional view showing the structure of a conventional door pocket.

FIG. 13 is a cross-sectional view showing the structure of a conventional injection molding die used for molding a door pocket.

FIG. 14 is a cross-sectional view showing a defect of a conventional injection molding die.

[Explanation of symbols]

 10 Car Door Trim 20 Door Pocket 21 Speaker Grill 22 Louver 30 Cavity Mold 32 Fixed Side Mold Plate 35 Groove 40 Core Mold 45 Core 46 Small Protrusion

Claims (2)

[Claims] 1. A fixed-side mold plate (3) having a predetermined mold surface shape.
2), a cavity mold (30) and a core mold (40) having a core (45) having a predetermined mold surface shape, and the fixed mold plate (32) and the core (45). A molten resin is injected and filled into a cavity formed between the resin molded body (20) and the groove (35) formed in the stationary mold plate (32), and the resin molded body (20) having the ridges (22, 61) is formed. ) In a required shape, a small protrusion (46) is formed in the core (45) corresponding to the groove (35) formed in the stationary mold plate (32). A mold for injection molding, which is characterized in that 2. The injection-molding die according to claim 1, wherein a plurality of grooves (35) are formed in parallel or in a grid pattern.