JP3194425B2 - Injection molding method and injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an injection molding method and an injection mold. More specifically, the present invention relates to an injection molding method and an injection mold capable of forming a molded article partially having a skin and capable of molding a skin without wrinkles.

[0002]

2. Description of the Related Art In general, an injection mold for producing a molded article having a partial skin is shown in FIG.
A vacuum suction pump 84 is provided by providing one of the pair of dies 81 and 82 (mainly a movable die) with a pore 83 for deaeration.
And the skin 85 is evacuated and the mold surface 9 of the movable mold 81 is evacuated.
0 (see (a) of FIG. 7). After that, the molten resin is injected through the manifold 86 into the back surface 87a of the skin 85 and the portion 87b without the skin 85 (see FIG. 7B). The cured molded product 88 is
The mold surface 90 with the retreat of the movable mold 81 (in the direction of arrow 89)
(See FIG. 7 (c)).

[0003] In the above-mentioned injection molding die, a thin plate-like material which has not been preformed is often used as a skin 85 before being made to conform to the die surface 90. A desired three-dimensional shape is formed along the surface 90.

[0004]

However, when the epidermis is moved along the mold, the edge of the epidermis is easily pulled and displaced by the central part of the epidermis moving largely toward the mold surface, and the formed epidermis is wrinkled. There is a problem of causing defects.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method and a mold for obtaining a molded article having a part of the skin, wherein the end of the skin is firmly fixed. It is an object of the present invention to provide an injection molding method and an injection mold capable of forming a molded product having a skin without wrinkle defects.

[0006]

In order to achieve the above-mentioned object, according to the present invention, the injection molding method according to the first aspect of the present invention provides an injection molding method comprising the steps of: A plurality of convex pieces for pressing and fixing the end of the epidermis inserted into the insertion groove toward the side surface of the insertion groove, and melting between them. A step of providing the resin so that the resin can flow, facing the back surface side of the skin toward the mold surface of the mold on which the resin is injected, and inserting an end of the skin into an insertion groove of the mold; and an end of the skin. Fixing with a convex piece, a step of injecting a molten resin to the back side of the skin so as to press the surface side of the skin against the mold surface of the other mold, and Through the molten resin passing between the pieces, the part with the skin and the part without the skin are connected It is characterized in that it comprises a step of forming a that resin layer. According to the first aspect of the present invention, the end of the skin can be firmly pressed and fixed by the convex piece, so that even if the end of the skin is pressed along the mold surface of the other mold by injecting a resin, the surface of the skin can be fixed. The ends do not shift. In addition, the resin layer formed on the back side of the skin and the resin layer formed on the part without the skin are integrally connected to each other, so that the boundary between the ends of the skin is beautiful and strong.

According to a second aspect of the present invention, in addition to the first aspect, the skin before being fixed to the mold is a flat plate which is not preformed. Although a preformed body can be used as the skin, the use of a flat plate that has not been preformed can be used to form the skin simultaneously with the formation of the resin layer. Can be omitted.

[0008] The invention according to claim 3 is the invention according to claim 1 or 2.
In addition to the described invention, an extrusion pin is provided which moves in a direction having both components of a direction in which the cured molded article is extruded from the mold surface and a direction in which the convex piece is removed from the cured molded article. This is a method in which the protrusion and retraction of the pin are linked with the convex piece. The extrusion pin protrudes from the mold surface and pushes out the molded article from the mold surface to remove it. On the other hand, the extrusion pin moves in a direction having both components of the extrusion direction of the molded article and the direction of removing the convex piece from the molded article (inward or outward with respect to the extrusion direction of the molded article). The convex piece interlocks with the extrusion pin and relatively moves in a direction perpendicular to the extrusion direction of the molded product. By the way, the convex piece presses the end of the skin toward the side surface of the insertion groove. To remove the convex piece from the undercut (the hollow part of the molded product) formed by the convex piece, it is necessary to push out the molded product. It is necessary to move the convex piece in a direction substantially perpendicular to the direction.
The extruding pin causes the convex piece to move in such a direction, so that the molded product is extruded and the convex piece is pulled out at one time. Note that the extrusion pin is connected to and driven by an extrusion mechanism conventionally provided in an injection mold.

According to a fourth aspect of the present invention, there is provided an injection molding die, wherein an insertion groove provided on a surface of the die for inserting an end portion of the skin, a plurality of the insertion grooves are provided at an appropriate interval, and one side surface of the insertion groove is provided. A fixture formed to be a part of a groove, a convex piece provided on one side of the fixture so that molten resin can flow between them, and a mold surface provided with the insertion groove A first mold provided with an introduction pipe for injecting the molten resin between the first mold and the skin whose end is fixed, and the skin fixed to the first mold is pressed by the injection of the molten resin. And a second mold having a mold surface. The end of the skin is fixed to the insertion groove of the first mold, which is the mold on the side where the resin is injected, using the convex piece and the fixing tool. Since this fixation is made mechanically and strong, molten resin is injected between the mold and the skin, and the skin moves so as to expand greatly,
Even when pressed against the surface of the second mold, which is the other mold, the end of the skin does not move. Also,
At this time, the skin is finally formed regardless of the presence or absence of the preforming. The ends of the skin are partially fixed by convex pieces provided on a plurality of fixing devices provided at intervals, and the molten resin flows between the convex pieces and the side having the skin. And a connected resin layer on the other side is formed.

The invention according to claim 5 has, in addition to the invention according to claim 4, both components in a direction in which the cured molded article is extruded from the surface of the mold and a direction in which the convex piece is removed from the cured molded article. An extrusion pin that moves in the direction is provided on the first mold, and a back surface of one side of the fixing tool on which the convex piece is provided is formed so as to be parallel to the direction of movement of the extrusion pin, and the fixing is performed. The tool is configured to move forward and backward in conjunction with the forward and backward movement of the push-out pin. The protruding piece presses the end of the skin toward the side surface of the insertion groove, in other words, in a direction substantially perpendicular to the direction in which the molded product is extruded. Therefore, the undercut of the molded product formed by the convex piece (the hollow portion of the molded product)
In order to pull out the projection from the projection, it is necessary to move the projection in a direction substantially perpendicular to the direction in which the molded product is extruded.
Therefore, the moving direction of the extrusion pin used to extrude the molded product from the mold surface is inclined with respect to the extrusion direction of the molded product (the inclination direction is the direction in which the convex piece is pulled out). Fixtures were provided. Also, since the back surface of the fixture on which the convex piece is provided is formed so as to be inclined with respect to the extrusion direction of the molded product so as to be parallel to the direction of movement of the extrusion pin, the first mold is moved by the movement of the fixture. There is no gap between the fixtures, and the end of the skin can be pressed more firmly by pushing the fixtures.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to illustrated examples. FIG. 1 is a schematic explanatory view of an embodiment of the injection molding method of the present invention, FIG. 2 is an explanatory view of a main part of an embodiment of the injection mold of the present invention, and FIG. FIG. 4 is a perspective explanatory view showing an example of a method and a molded product molded by an injection mold, FIG. 4 is a side sectional view of another embodiment of the injection mold of the present invention, and FIGS. It is principal part explanatory drawing and side sectional drawing of further another Example of an injection mold.

Referring to FIG. 1, the injection mold of the present invention comprises a first mold 1 and a second mold 2. The first mold 1 has an inlet tube 3 for injecting a molten resin, and an insertion groove. 4, a fixture 6 having a convex piece 5, and an extrusion pin 7 are provided. Reference numeral 10 denotes a skin, and FIG. 1A shows a state in which the end 11 is fixed to the insertion groove 4. In the present invention, as the skin 10 before being fixed to the insertion groove 4, a thin plate-like material that has not been formed at all can be used. ) Can also be used. In addition, FIG.
In the figure, reference numeral 13 denotes a resin layer,
The portion 3a and the portion 13b that is not provided are integrated.

As the first mold 1 and the second mold 2, a fixed mold and a movable mold which are usually used as an injection mold can be used. Usually, an injection cylinder for supplying a molten resin is connected to a fixed mold, and a product pushing mechanism is provided for a movable mold. The first mold on the side where the resin is injected in the present invention is preferably this fixed mold, and the fixed mold is also provided with a product extrusion mechanism. However, the present invention is not limited to this, and it is also possible to provide a product extruding mechanism having the introduction tube 3 for injecting the resin into the movable mold and the extruding pin 7 to fix the skin.

The insertion groove 4 is provided on the mold surface 8 of the first mold 1 so as to surround the skin 10, and the end 11 of the skin 10 is inserted. As shown in FIG. 2, one side surface 14 of the insertion groove 4 partially corresponds to one side surface 15 of the fixture 6.
Sharing. As shown in FIG. 3, a plurality of the fixing tools 6 are arranged in the insertion groove 4 at appropriate intervals to partially press around the end 11 of the skin 10.

As shown in FIG. 2, the fixture 6 has a convex piece 5 on one side surface 15 on the side of the insertion groove 4. The width W of the fixture 6 is about 10 to 30 mm, preferably about 20 mm, so as not to interfere with a cooling pipe (not shown) disposed in the first mold 1. Further, the fixture 6 is fixed to the tip of the push-out pin 7, and interlocks with the push-out pin 7. Also, the surface 18 on the back side of the side surface 15
Is parallel to the moving direction 23 of the extrusion pin 7 and is inclined with respect to the extrusion direction 21 of the molded product. The fixture 6 is the surface 1
Since the projection 8 is tilted in this manner, no gap is formed between the surface 18 and the first mold 1 even when the projection 8 moves in conjunction with the advance / retreat operation of the push pin 7. Further, by pushing in the fixing tool 6, the convex piece 5 is moved to one side surface 16 of the insertion groove 4.
, And the end portion 11 of the skin 10 can be pressed more firmly.

As shown in FIG. 2, the convex piece 5 is provided on the side surface 15 of the fixture 6 so as to project toward the other side surface 16 of the insertion groove 4. Further, the end portion 11 of the skin 10 is partially fixed, not over the entire width, so that the molten resin can flow between the convex pieces 5. The molten resin that has passed through between the convex pieces 5 forms a resin layer 13 in which the portion 13a with the skin 10 and the portion 13b without the skin 10 are integrated. As a result, the molded article is excellent in the beauty of the end portion of the skin and is strong.

When the outer skin 10 is fixed, the fixing tool 6 is provided at the tip of the push-out pin 7, so that the push-out pin 7 is protruded to take out the fixation tool 6 from the insertion groove 4.
After the end 11 of the skin 10 is inserted into the insertion groove 4, the pushing pin 7 is retracted so that the fixing tool 6 is fitted into the insertion groove 4. At this time, the convex piece 5 is fixed by pulling the end portion 11 of the skin 10 toward the depth of the insertion groove 4.
The epidermis 10 can be more firmly fixed. And
In other words, so that the molten resin injected into the back surface of the skin 10 presses the skin 10 toward the mold surface of the second mold 2, so to speak,
Even if the epidermis 10 is pulled from the center side of the epidermis 10 toward the end 11 in such a manner as to expand the epidermis 10, the epidermis 10 is firmly fixed by the convex pieces 5, so that the epidermis 10 does not shift and has wrinkle defects. Do not wake up. Thus, the convex piece 5
The shape is not limited to the rectangular projections in the illustrated example as long as the end of the skin can be firmly fixed while allowing the flow of the molten resin, and a cylindrical projection, a truncated cone, a hemisphere, etc. are possible. is there.

The push pin 7 is, as shown in FIG.
It is configured to be able to protrude from the mold surface 8 by a driving mechanism such as an extruding plate 20 disposed on the base side. As shown by arrows 21, 22 and 23 in FIG. 1C, the moving direction 23 of the extrusion pin 7 is the same as the extrusion direction 21 of the product (cured molded product) and the undercut ( It has both components in the direction 22 in which it is pulled out from the hole 25 formed in the product 9 by the convex piece 5. On the other hand, the push-out pin 17 indicated by a two-dot chain line is the same as that used conventionally, and is in the product push-out direction (arrow 21 direction).
It only moves on and off. The first mold 1 has an extrusion pin 7
In addition, an extrusion pin 17 is appropriately provided as needed.
Since the fixture 6 is provided at the tip of the pushing pin 7 that moves in this manner, the convex piece 5 can be removed from the undercut 25 at the same time as the product 9 is pushed.

The introduction tube 3 provided in the first mold 1 is used to supply the molten resin injected from the injection cylinder to a substantially central portion of the back surface 13a of the skin 10 and a portion 13b having no skin 10b.
Is to be introduced. As shown in FIG. 1B, the molten resin injected into the back surface 13 a of the skin 10 presses the skin 10 against the surface of the second mold 2,
The molding of 0 is performed in an auxiliary manner. Therefore, in order to prevent the molten resin from entering the front side of the skin 10 (between the skin 10 and the mold surface of the second mold 2), the molten resin is melted from the back side 13a of the skin 10 toward the portion 13b where the skin 10 is not provided. The flow rates of the introduction pipes 3a and 3b are adjusted so that the resin flows.

The present invention is preferably used for forming a relatively flat product using a composite skin, without the necessity of preforming the skin, and simultaneously forming the resin layer and forming a three-time-limited shape on the skin. Can be formed. Specifically, it is suitably used for forming door trims and pillars. Moreover, as the skin 10, what consists only of a solid surface layer,
Appropriate use of a single skin or a composite skin such as a two-layer structure in which a foam layer for imparting cushioning properties is attached to a solid surface layer, or a three-layer structure in which an inner layer is further provided. Can be. The material of the skin 10 is PVC, styrene-based thermoplastic elastomer (TPU),
A polyester thermoplastic elastomer (TPAE) or the like is used. The material of the resin layer 13 is preferably a polyolefin-based thermoplastic resin.
(Polypropylene) and PE (polyethylene) are preferably used.

Next, the injection molding method of the present invention will be described with reference to FIG.

First, before fixing the skin 10, the pusher pin 7 of the first mold 1 is advanced from the mold surface 8, and the fixture 6 is removed from the insertion groove 4. Next, the back side of the skin 10 faces the mold surface 8 of the first mold 1, the end 11 of the skin 10 is inserted into the insertion groove 4, and the push-out pin 7 is driven to retract the fixture 6. The end portion 11 of the skin 10 is firmly fixed with the convex piece 5 while being pulled toward the deep part of the insertion groove 4 (see FIG. 1A).

Next, a molten resin is introduced from the introduction tube 3 through the skin 10.
Into the back side 13a and the portion 13b without the skin 10. The molten resin injected into the back surface 13 a of the skin 10 presses the surface of the skin 10 against the surface of the second mold 2 to form the skin 10. In addition, between the convex pieces 5, the molten resin is applied from the back surface 13 a of the skin 10 to the portion 1 without the skin 10.
3b, the resin layer 13 is formed by integrally connecting the portion 13a with the skin 10 and the portion 13b without the skin 10 at the end 11 of the skin 10 (see FIG. 1B).

When the molded article 9 has hardened, the first mold 1 and the second mold 2 are opened, the extrusion plate 20 is moved, and the extrusion pins 7 and 17 are advanced (see FIG. 1C). ). At this time, the fixture 6 provided at the tip of the push-out pin 7 moves relative to the molded product 9 by an arrow 22.
The convex piece 5 is removed from the undercut 25 at the same time when the molded article 9 is taken out. The product example shown in FIG. 3 is a door trim, and the molded product 9 taken out of the molds 1 and 2 is punched out of the punched portions 26 and 27 after a predetermined process.

Next, another embodiment of the present invention will be described with reference to FIGS.

In the injection mold shown in FIG. 1, the convex piece 5 is configured to press the back side from the front side of the skin 10 to the side face 16 of the insertion groove 4, but the present invention is not limited to this. As shown in FIG. 4, the front side 32 may be configured to be pressed against the side surface 33 of the insertion groove 4 from the back side 31 of the skin. In this case, the direction of inclination of the extrusion pin 34 is opposite to that of the injection mold of FIG. 1, but the movement direction 43 of the extrusion pin 34 is a component of both the product extrusion direction 41 and the extraction direction 42 of the convex piece 5. In that it has

The injection mold shown in FIG. 5 and FIG.
It is not a push pin, but a fixture 5 with a hydraulic cylinder 51.
The fixture 52 is fixed to the tip of the piston rod 53 so that the piston 2 moves. In this case, since the moving direction of the fixture 52 and the pressing and pulling directions of the convex piece 5 are the same, it is not necessary to incline the back surface 18 as in the fixture 6 shown in FIG. Absent. In addition, the fixing device can be configured to be moved by using a conventional appropriate driving mechanism.

[0028]

As described above, according to the first and fourth aspects of the present invention, the end of the epidermis inserted into the insertion groove by the convex piece can be mechanically firmly pressed and fixed. As a result, there is no deviation due to resin injection. Also, since the resin can flow from the portion having the skin to the portion without the skin between the convex pieces, the resin layer formed on the back side of the skin and the resin layer formed on the portion without the skin are integrated. The edge of the epidermis is beautifully and firmly bound.

The surface of the skin is pressed against the surface of the other mold in such a manner that the surface is swollen from the center by the molten resin injected from the back side of the skin.
Final shaping (with or without pre-shaping) is performed. Therefore, the preforming step can be omitted by using a material that has not been preformed.

Further, according to the second or fifth aspect of the present invention, the extrusion of the molded article and the withdrawal of the convex piece are simultaneously performed only by changing the extrusion direction of the conventional extrusion pin. It is easy to change the device.
In addition, since the back surface of the fixture is inclined, no gap is created between the first mold and the movement of the fixture, and the edge of the skin can be firmly pressed by pushing the fixture.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of one embodiment of the injection molding method of the present invention.

FIG. 2 is an explanatory view of a main part of an embodiment of the injection mold of the present invention.

FIG. 3 is an explanatory perspective view showing an example of a molded product molded by an injection molding method and an injection molding die of the present invention.

FIG. 4 is a side sectional view of another embodiment of the injection mold of the present invention.

FIG. 5 is an explanatory view of a main part of still another embodiment of the injection mold.

FIG. 6 is a side sectional view of still another embodiment of the injection mold.

FIG. 7 is an explanatory diagram of an example of a conventional injection molding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st metal mold 2 2nd metal mold 3 Introductory pipe 4 Insertion groove 5 Convex piece 6, 52 Fixture 7, 34 Extrusion pin 8 Mold surface (1st metal mold) 9 Product (hardened molded article) 10 Skin 11 Skin 13 Resin layer 13a Resin layer on the back side of skin (part with skin) 13b Resin layer on part without skin 14, 16 Side surface of insertion groove 4 15 One side surface of fixture 6 18 Back surface of fixture 6 21 Product extrusion direction 22 Convex piece withdrawal direction 23 Extrusion pin moving direction

Continuation of the front page (72) Inventor Shinya Kato 4-1-1-21 Hamazoedori, Nagata-ku, Kobe-shi, Hyogo Mitssei Belt Co., Ltd. (56) References JP-A-10-34659 (JP, A) JP-A-2- 102011 (JP, A) JP-A-7-195422 (JP, A) JP-A-2-142004 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45 / 84

Claims (5)

(57) [Claims] An insert groove for inserting an end of a skin is provided in a mold of a pair of molds on a resin injection side, and an end of the skin inserted in the insert groove is inserted into the insert groove. A plurality of convex pieces for pressing and fixing toward the side surface of the mold are provided so that the molten resin can flow between them, and the back side of the skin is directed toward the mold surface of the mold on which the resin is injected. Inserting the end of the skin into the insertion groove of the mold, fixing the end of the skin with the convex piece, and pressing the surface of the skin against the mold surface of the other mold. A step of injecting the molten resin into the back side of the skin, and forming a resin layer connecting the portion with the skin and the portion without the skin by passing the molten resin between the convex pieces at the end of the skin. An injection molding method characterized by comprising a step of: 2. The injection molding method according to claim 1, wherein the skin before being fixed to the mold is a flat plate that has not been preformed. 3. An extrusion pin is provided which moves in a direction having both components of a direction in which the cured molded article is extruded from the surface of the mold and a direction in which the convex piece is removed from the cured molded article. The injection molding method according to claim 1, wherein the reciprocating operation and the convex piece are linked. 4. An insertion groove provided on a surface of a mold for inserting an end portion of a skin, and a plurality of insertion grooves provided at appropriate intervals in the insertion groove so that one side thereof becomes a part of the insertion groove. A fixing member to be formed; a convex piece provided on the one side surface of the fixing member so that a molten resin can flow between them; a mold surface provided with the insertion groove and a skin fixed to an end portion second gold having a first mold, and a fixed skin is that type surface pressed by the injection of the molten resin to the first mold and the inlet pipe for injecting the molten resin is provided between the An injection mold comprising: a mold; 5. An extrusion pin, which moves in a direction having both components of a direction in which a cured molded article is extruded from the surface of the mold and a direction in which the convex piece is removed from the cured molded article, is provided in the first mold. The back surface of the one side provided with the convex piece of the fixing tool is formed so as to be parallel to the moving direction of the push-out pin, and the fixing tool advances and retreats in conjunction with the movement of the push-out pin. The injection mold according to claim 4, which is formed.