JP2006281463A - Injection mold assembly and injection molding method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and certainly fix an insert component provided with a hole to a movable mold. <P>SOLUTION: This injection mold assembly comprises the pin 5, which extends to a cavity 4 from the side of the movable mold 3 and of which the leading end part is inserted in the hole 12a of the insert component 12, and is provided with a fixing means A formed to the leading end part of the pin 5 and freely extending and contracting with respect to the hole 12a of the insert component 12. A relative moving means B of the inner pin 23 and the pin 5 is provided in order to extend and contract the leading end part of the pin 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an injection mold apparatus for injection molding a molded part integrally with an insert part and an injection molding method using the same.

As an injection molding die device for injection molding of a molded part integrally with an insert part, for example, in JP-A-9-109188, a lower mold on which an insert part is placed and a lower mold are closed. Proposed to have an upper mold with a clearance formed between the upper surface of the insert part and the upper mold provided with a pressing pin that pushes the insert part into the lower mold and fixes it during injection molding of the molded part Has been.
The insert part is pushed and fixed by a pressing pin protruding from the upper mold on the movable side toward the lower mold on the fixed side.

  However, as in the case of the molded product shown in FIG. 7, when the insert part is attached to the movable mold and all the parts other than the attachment surface are covered with the resin in the cavity, the insert part is moved from one mold to the other. It cannot be fixed by being pushed in with a holding pin toward the mold.

In such a case, it is conceivable to hold the insert part by providing a pin protruding from the movable mold, providing a hole in the insert part, and passing the hole of the insert part through the pin.
JP-A-9-109188

  However, when the pin is fixed to the hole of the insert part through a pin, if the degree of fitting is increased, a large force is required when the insert part is removed from the pin together with the molded product. Further, if the degree of fitting is weakened, there is a risk that the insert part may be displaced in the cavity such as misalignment.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection mold apparatus capable of easily and reliably fixing an insert part provided with a hole to a movable mold, and It is to provide an injection molding method using the same.

The injection mold apparatus of the present invention includes a movable side mold installed on a movable side plate that is movable with respect to a fixed side mold, and the movable side mold and the fixed side from the side of the movable side mold. A pin extending to a cavity formed by a side mold and having a tip inserted into a hole of an insert part, and a fixing means formed at the tip of the pin and capable of being expanded and contracted with respect to the hole of the insert part Is an injection molding die apparatus.
According to this device, the tip end portion of the pin inserted into the hole of the insert part expands, so that the outer periphery of the pin tip part closely adheres to the hole of the insert part, and the insert part can be fixed without shifting to a predetermined position. it can. Moreover, when the tip of the pin inserted into the hole of the insert part is reduced in diameter, the molded product integrated with the insert part can be easily extracted.

The fixing means includes an expansion / contraction elastic piece formed by vertically dividing the tip of the pin into two or more, a tapered taper hole formed in the center of the expansion / contraction elastic piece, It is preferable to include an inner pin disposed in the center hole and having a tip engaged with the tapered hole, and a relative moving means for the pin and the inner pin.
According to this, due to the relative movement of the inner pin toward the tip of the pin, the inner pin expands the tapered taper hole of the pin, the expansion / contraction elastic piece at the tip of the pin opens in the diameter increasing direction, and the inner pin extends from the tip of the pin. By the relative movement away, the inner pin comes out from the tapered taper hole of the pin, and the expansion / contraction elastic piece at the tip of the pin closes in the diameter reducing direction. Thus, the expansion / contraction elastic piece at the tip can be expanded / contracted by the relative movement between the inner pin and the pin.

In the relative movement means, the inner pin is fixed to the movable-side mold, the pin is fixed to a protruding plate that moves in the movable direction within the movable-side mold, and the relative direction relative to the movable direction of the protruding plate is By movement, the pin moves relative to the inner pin, and when the protruding plate moves in the anti-extrusion direction, the expansion / contraction elastic piece opens, and the insert part is fixed while being pulled into the movable side mold. What is a thing is preferable.
The ejection plate is provided with an ejection pin for projecting a molded product, and is movable in the movable direction. For this reason, when this protruding plate moves in the protruding direction (cavity side) to protrude the molded product, the pin also moves in the protruding direction, away from the inner pin fixed to the movable mold, and the expansion / contraction elastic piece at the tip of the pin is Closed state. The hole of the insert part can be easily passed through the pin tip in the closed state. When the protrusion plate moves in the anti-protrusion direction and returns the protrusion pin to its original position, the tip of the inner pin fixed to the movable side engages with the taper hole of the pin, and the expansion / contraction elastic piece at the tip of the pin opens. Since the pin moves in the anti-extrusion direction, the insert part is fixed while being drawn into the core surface of the movable mold. Therefore, the insert part is firmly fixed at a predetermined position on the core surface of the movable mold.

The injection molding method of the present invention includes a movable side mold installed on a movable side plate that is movable with respect to the fixed side mold, the movable side mold and the fixed side mold from the movable side plate. A pin that is a cone-shaped taper surface that extends to the cavity formed in (1) and is divided in a vertically-divided shape, and the inner peripheral surface of the divided portion becomes smaller in diameter toward the cavity. An inner pin installed on the inner periphery and movably mounted in the pin; the pin is inserted into an insert part having a hole; and the inner pin is moved relative to the cavity side in the pin. The injection molding method is characterized by injecting molten resin into the cavity after expanding the divided tip of the pin and fixing the insert part.
According to the above method, the inner pin moves relative to the cavity side in the pin, so that the tip part divided by the pin can be expanded and the insert part can be fixed, and in that state, the molten resin is injected into the cavity. Then, the insert component does not shift. Further, when the inner pin moves relative to the side opposite to the cavity in the pin, the divided tip end portion of the pin becomes narrow as before, and the insert part can be easily extracted together with the molded product.

Further, in the above method, the base end of the pin is movable in the protruding direction, is fixed to a protruding plate having a protruding pin, and interlocks with the movement of the protruding plate in the anti-projecting direction. It is preferable that the insert part is fixed by expanding the divided tip end portion of the pin by the relative movement of the pin toward the cavity in the pin.
According to this, while the ejector plate ejects the molded product, the pin also projects in conjunction with it, and the tip of the pin is also closed at the same time, so the molded product integrated with the insert part can be easily extracted, and the next molding Insert parts for products can also be easily inserted. When the protruding plate returns to the original position, the pin is also retracted at the same time, but since the tip of the pin is opened, the inserted insert part is fixed while being pulled. Therefore, the insert part is firmly fixed at a predetermined position of the movable mold.

  According to the injection mold apparatus and the injection molding method described above, the insert part fixed to the movable mold is fixed by the expansion and contraction of the tip of the pin that passes through the hole. When the diameter is increased, the molded product integrated with the insert part can be easily extracted, or the next insert part can be easily inserted. Further, when the pin tip portion is widened with the pin tip portion inserted into the hole of the insert component, the insert component can be fixed to the movable mold so as not to be displaced. As a result, the insert part with a hole can be easily and reliably fixed to the movable mold.

  Hereinafter, an embodiment of an injection mold apparatus and an injection molding method using the same according to the present invention will be described with reference to the drawings.

First, a configuration of an injection mold apparatus according to an embodiment of the present invention will be described with reference to FIG.
In FIG. 1, an injection mold apparatus 1 includes a fixed mold 2, a movable mold 3 installed on a movable plate 10 that is movable with respect to the fixed mold 2, and a movable mold. 3 is extended to the cavity 4 formed by the movable mold 3 and the fixed mold 2, and the tip 5 is inserted into the hole of the insert part 12, and the tip 5 is formed at the tip of the pin 5. And fixing means A that can be expanded and contracted with respect to the hole of the insert part 12.

The stationary mold 2 is formed as a cavity mold having a recess. The fixed mold 2 is fixed to an injection molding machine base (not shown).
The stationary mold 3 includes a cavity mold main body 13 and an attachment portion 14. A resin introduction path 11 is formed from the attachment portion 14 to the mold body 13. An injection unit (not shown) can be freely connected to the inlet of the resin introduction path 11, and the resin can be injected into the cavity 4 from here.

The movable mold 3 is formed in a core mold having a convex portion. The movable mold 3 is installed on a movable plate 10 that is movable with respect to the fixed mold 2. In the illustrated example, the movable direction X is a horizontal direction.
The movable mold 3 includes a core mold body 15, spacers 16 and 16, and a mounting plate 17. In a state where the molds 2 and 3 are closed, is the resin filled between the core mold body 15 and the cavity mold body 13? Cavity 4 is formed (see FIG. 5).
A protruding plate 18 is movably provided in the movable direction X in the movable mold inner space formed by the divided spacers 16 and 16. The protruding plate has an unillustrated protruding pin for protruding a molded product from the core surface of the core body 15.

The pin 5 whose tip is inserted into the hole 12 a of the insert part 12 is a cylindrical body having a center hole 20, and its base end is fixed to the protruding plate 18.
Fixing means A that can be expanded and contracted with respect to the hole 12 a of the insert part 12 is formed at the tip of the pin 5.

  As shown in FIG. 2, the fixing means A includes expansion / contraction elastic pieces 21, 21 formed by vertically dividing the tip portion of the pin 5 into two or more, and a center hole 21 of the expansion / contraction elastic pieces 21, 21. A taper-shaped tapered hole 22 formed on the side, an inner pin 23 disposed in the center hole 20 of the pin 5 and having a tip engaged with the tapered hole 22, and a relative moving means B between the pin 5 and the inner pin 23; It is equipped with.

  The expansion / contraction elastic pieces 21 and 21 are formed by vertically dividing the pin tip portion into two by the cut line 24. By dividing the tip portion of the pin 5 into two or more expansion / contraction elastic pieces 21, 21, the tip portion can be expanded or closed. Note that the number of vertical divisions of the pin tip is not limited to two, and may be multiple divisions such as three divisions or four divisions.

  The taper hole 22 has a tapered surface that becomes narrower than the center hole 20 toward the tip. The tip 25 of the inner pin 23 disposed in the center hole 20 is formed on the C surface or the R surface. When the inner pin 23 reaches the advanced position toward the tip of the pin 5, the tapered hole 22 and the tip 25 of the inner pin 23 are engaged, and the expansion / contraction elastic pieces 21, 21 are pushed out like a two-dot chain line. As shown in the figure, when the inner pin 23 is in the retracted position with respect to the tip of the pin 5, the expansion / contraction elastic pieces 21 and 21 return to a closed state as indicated by a solid line by elastic force.

  The expansion allowance of the expansion / contraction elastic pieces 21 and 21 at the tip of the pin 5 is determined such that the hole diameter 12a of the insert 21 and the outer diameter when the pin 5 is closed are less than 0.1 mm. In order to insert and remove the tip of the pin 5 in the hole 12a of the insert 21, a gap of less than 0.1 mm is sufficient. Moreover, resin with a high viscosity does not enter that it is a clearance less than 0.1 mm.

The relative movement means B between the pin 5 and the inner pin 23 is formed by fixing the base end of the inner pin 23 to the mounting plate 17 of the movable mold 2 and fixing the base end of the pin 5 to the protruding plate 18. .
The ejecting plate 18 is movable between an ejecting direction (cavity direction) and an anti-projecting direction (anti-cavity direction) so that an ejecting pin for projecting a molded product can be ejected from the core mold surface. . Relative moving means B is formed so as to be interlocked with the movement of the protruding plate 18.

In FIG. 2, when the protruding plate 18 moves in a position where the protruding pin is retracted, that is, in the opposite protruding direction, the tip of the pin 5 is retracted to the position of the two-dot chain line, and becomes a length that fits in the hole 12 a of the insert part 12. At this time, the tip portion of the pin 5 is opened by engagement of the tapered hole 22 and the tip portion of the inner pin 23, and is in a fixed state in close contact with the center hole 12 a of the insert part 12.
When the protrusion plate 18 moves to the position where the protrusion pin protrudes, that is, the protrusion position, the tip of the pin 5 advances to the position of the solid line, and the molded product integrated with the insert part 12 is protruded. That is, the pin 5 is also used as a protruding pin. In the advanced pin 5, the tip of the inner pin 23 is removed from the tapered hole 22, and the tip of the pin 5 is closed. Therefore, the insert part 12 integrated with the molded product can be easily extracted from the tip of the pin 5. Also, the insert part 12 for the next molding can be easily inserted into the pin 5 and pushed into the installation position of the two-dot chain line.

  Next, an injection molding method using the injection mold apparatus having the above-described configuration will be described with reference to FIGS. 1 and 3 to 7.

[Process of inserting insert parts]
In FIG. 1, the movable side mold 3 is open with respect to the fixed side mold 2. Further, the protruding plate 18 moves in the protruding direction (cavity side) of the circled numeral 1, and the pin 5 also protrudes from the original position where the insert part 12 is held. In this state, the tip of the pin 5 is in a closed diameter reduced state as indicated by the solid line in FIG. Therefore, the insert part 12 can be inserted toward the tip of the pin 5 as indicated by the round numeral 2. At this time, as shown in FIG. 3, the insert part 12 is pushed to the root of the pin 5, that is, to the inlay portion of the core surface of the movable mold 3.

[Fixed positioning process for insert parts]
As shown in FIG. 3, the protruding plate 18 is moved in the anti-extrusion direction as indicated by the circled numeral 3, and is moved to a position where the tip of the unillustrated protruding pin is coincident with the core surface of the movable mold 3. Then, the inner pin 23 remains fixed to the movable mold 3, but the pin 5 fixed to the protruding plate 18 is retracted, as if the inner pin 23 moves toward the tip inside the pin 5. It becomes a movement. Then, as shown in the enlarged partial view of FIG. 4, the tip of the pin 5 opens, and the outer periphery of the tip of the pin 5 presses against the hole of the insert part 12. The tip of the pin 5 is pulled into the movable mold 3 while this pressing becomes strong. Therefore, the insert part 12 is fixed while being drawn toward the movable mold 3. As a result, the bottom surface of the insert part 12 is in close contact with the spigot part of the movable mold 3 and the outer peripheral surface of the hole 12a of the insert part 12 is concentric by the outer peripheral part of the pin 5 biased in the diameter increasing direction. It is fixed with.

[Integration process of insert parts and molded products]
As indicated by the circled numeral 4 in FIG. 4, the movable side mold 3 is moved toward the fixed side mold 2, and the mold is closed. When the mold is closed, the molten resin is injected into the cavity 4 through the resin introduction path 11 as indicated by the circled numeral 5 in FIG. And when resin solidifies to some extent, the molded article 7 integrated with the insert component 12 will be formed (refer FIG. 7). The molded product 7 is in a state of being embedded in the resin except for the bottom surface of the insert part 12.
At this time, as shown by a two-dot chain line in FIG. 2, the tip of the pin 5 is open, but the opening dimension α is less than 0.1 mm, and a highly viscous resin does not enter.

[Protruding process of molded product integrated with insert parts]
As shown by the circled number 6 in FIG. 6, the movable side mold 3 is moved with respect to the fixed side mold 2, and the mold is opened. At this time, the molded product 7 remains in the core mold of the movable mold 3.
As shown by the round numeral 7 in FIG. 7, the protruding plate 18 is advanced in the protruding direction (cavity side). Then, the molded product 7 is protruded from the core surface of the movable mold 3 by the tip of the pin 5 that moves in conjunction with an unillustrated protrusion pin.
At this time, since the tip end portion of the pin 5 is in a closed state as shown by the solid line in FIG. 2, the insert part 12 integrated with the molded product 7 can be easily extracted from the tip end portion of the pin 5. it can.
When the molded product 7 is taken out, the state returns to the state of FIG. 1, and the insert part 12 for the next molded product can be easily inserted into the tip of the pin 5.

  As described above, the injection mold apparatus of the present embodiment has the fixing means A that can be expanded and contracted with respect to the hole of the insert part 12 at the tip of the pin 5. When the diameter of the tip of the pin 5 to be inserted is increased, the pin 5 is brought into close contact with the hole of the insert part 12 and can be fixed without shifting to a predetermined position. Moreover, when the tip of the pin 5 inserted into the hole of the insert part 12 is reduced in diameter, the molded product integrated with the insert part 12 can be easily extracted.

  Further, as shown in FIG. 2, the tip of the pin 5 is divided and formed into the expansion / contraction elastic pieces 12 and 12, and a tapered hole 22 is provided in the tip of the pin 5, and the inside of the center hole 20 of the pin 5 Since the inner pin 23 that advances and retreats and the tapered hole 22 are engaged, the expansion / contraction elastic pieces 12 and 12 can be made to perform a minimum expansion / contraction operation that is less than 0.1 mm and that is necessary for gripping or opening. .

  Further, the inner pin 23 is fixed to the mounting plate 17 of the movable side mold 3, and the pin 5 is provided to be movable in the mold moving direction in the movable side mold 3, and fixed to the protruding plate 18 having a protruding pin. Since the structure is such that the pin 5 and the inner pin 23 move relative to the movement of the protruding plate 18. Therefore, it is not necessary to separately provide advancing / retreating drive means for the inner pin 23 for expanding / reducing the tip of the pin 5. Further, the pin 5 can also be used as a protruding pin and can be used for protruding a molded product.

Although the present invention has been described based on a preferred embodiment, the present invention can be modified within the scope not exceeding the gist thereof.
First, as shown in FIG. 8, the tip of the inner pin 23 slightly protrudes from the tip of the pin 5, whereby the tip of the pin 5 can be expanded in diameter. In this case, since the inner pin 23 blocks the tip portion of the pin 5, the resin is more reliably prevented from entering the tip portion of the pin 5.

Further, as the relative movement means B between the pin 5 and the inner pin 23, it is preferable to use the protruding plate 18, but the invention is not limited to this.
The tip of the pin 5 is fixed to the movable mold 3 with the depth of the hole of the insert part 12 projecting from the core surface, and is separately provided for advancing and retracting the inner pin 23 disposed in the center hole of the pin 5. An advance / retreat driving means may be provided. In this case, the advancing / retreating drive means is driven to advance / retreat in conjunction with the opening / closing of both molds 2 and 3, and when the mold is opened, the tip of the pin 5 is reduced in diameter, and when the mold is closed, the tip of the pin 5 is expanded do it.

It is explanatory drawing which showed the example of embodiment of the mold apparatus for injection molding of this invention, and is the figure which showed the mold open state. It is an expanded partial sectional view of a pin tip part. It is a figure which shows the procedure of the injection molding method of this invention. It is a figure which shows the procedure of the injection molding method of this invention. It is a figure which shows the procedure of the injection molding method of this invention. It is a figure which shows the procedure of the injection molding method of this invention. It is a figure which shows the procedure of the injection molding method of this invention. It is an expanded partial sectional view of the other pin tip part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold apparatus 2 Fixed side mold 3 Movable side mold 4 Cavity 5 Pin 12 Insert part 18 Extrusion plate 20 Center hole 21 Expansion / contraction elastic piece 22 Taper hole 23 Inner pin A Fixing means B Relative movement means

Claims (5)

  A movable mold installed on a movable plate that is movable with respect to the fixed mold, and extends from the movable mold side to a cavity formed by the movable mold and the fixed mold. An injection mold apparatus having a pin provided and having a tip inserted into a hole of an insert part, and a fixing means formed at the tip of the pin and capable of expanding and contracting with respect to the hole of the insert part.   The fixing means includes an expansion / contraction elastic piece formed by vertically dividing a tip portion of the pin into two or more, a tapered taper hole formed on a center side of the expansion / contraction elastic piece, and a center hole of the pin The mold apparatus for injection molding according to claim 1, further comprising: an inner pin that is disposed on the front end of the pin and engages with the tapered hole, and a relative moving means for the pin and the inner pin.   In the relative movement means, the inner pin is fixed to the movable mold, the pin is fixed to a protruding plate that moves in the movable direction in the movable mold, and the movement of the protruding plate in the movable direction The pin moves relative to the inner pin, and when the protruding plate moves in the anti-extrusion direction, the expansion / contraction elastic piece opens, and the insert part is fixed while being pulled into the movable side mold. The injection molding apparatus according to claim 2.   A movable side mold installed on a movable side plate that is movable with respect to the fixed side mold, and a tip extending from the movable side plate to a cavity formed by the movable side mold and the fixed side mold The portion is divided in a vertically split shape, and a pin that is a conical tapered surface that becomes smaller in diameter as the inner peripheral surface of the divided portion becomes the cavity side, and is installed on the inner periphery of the pin, and inside the pin An inner pin that is movably attached, the pin is inserted into an insert part having a hole, and the inner pin is moved relative to the cavity in the pin, thereby dividing the tip of the pin. An injection molding method characterized by injecting molten resin into the cavity after spreading the insert part and fixing the insert part.   A base end of the pin is movable in a protruding direction and is fixed to a protruding plate having a protruding pin, and the inner pin is cavityd in the pin in conjunction with the movement of the protruding plate in the counter protruding direction. The injection molding method according to claim 4, wherein the insert part is fixed by expanding a divided tip end portion of the pin by relative movement to the side.

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