JP2006026984A - Mold for insert molding, insert molded product and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for insert molding capable of supporting an insert part by a resin by a simple structure without damaging the insert part, an insert molded product and its manufacturing method. <P>SOLUTION: The mold for insert molding is constituted of an upper mold 1 and a lower mold 2 for sliding a movable body 12 provided with a second gate 1e in the direction of a second cavity 1d after a second molten resin wb is injected to urge the insert part w1 toward a first cavity 1a by the resin in the second cavity 1d. Then, the insert molded product W is manufactured using the mold A for insert molding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mold for insert molding, an insert molded body, and a method for manufacturing an insert molded body used when an integrated product is formed by wrapping and solidifying an insert product with a molten resin.

  Conventionally, there is insert molding as a molding method in which a desired part made of metal or other material is embedded in a resin or the like.

  For example, as the one molded by this insert molding (insert molded body), the inner periphery of the substantially cylindrical insert part (magnet) is covered with resin like a magnet rotor which is one component part of a motor. There is something that is formed.

  As a method for producing such an insert molded body, for example, an injection molding process for introducing molten resin to at least a part of the inner periphery and outer periphery of the insert part, and after the molten resin is cooled and solidified, at least the outer periphery thereof Manufacture is provided with a peripheral resin removal step of removing a peripheral resin portion covering a part.

  According to this insert molding method, the pressure of the molten resin applied to the inner peripheral side can be offset or reduced by the molten resin pressure applied to the opposing outer peripheral side, and as a result, the insert part is pushed from the inner peripheral side. The acting force to be spread can be removed or alleviated, and therefore it is possible to prevent the deformation of the insert part and, in some cases, the phenomenon of breakage (see, for example, Patent Document 1).

JP 2004-58407 A (page 3, FIG. 1)

  The above-described insert molding method is considered to be preferable as a method for overcoming the above-mentioned problems as compared with a method for mechanically supporting the outer periphery of an insert part (prior art in the prior art document). Is left.

  That is, in the above-described insert molding method, when the outer resin part solidifies faster than the inner resin part on which the insert part of the substantially cylindrical body is mounted, the outer periphery resin shrinks after molding of the outer resin. A gap is generated between the resin and the insert part.

  In such a case, as a matter of course, the support of the magnet by the outer peripheral resin cannot be obtained, and as a result, the insert part is damaged by the injection pressure from the inside.

  If the solidification timing of the peripheral resin is adjusted, the gaps described above will not occur during insert molding, but in reality, the peripheral resin part volume and product volume are optimized, the gate diameter is optimized, and the resin inflow speed is It is extremely difficult to optimize the temperature and strictly control the temperature in consideration of variations in the flow of molten resin and productivity.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an insert molding die, an insert molded body, and a method for manufacturing the insert molded body that can support the insert part with a resin with a simple structure without damaging the insert part. And

In order to achieve the above-mentioned object, the following technical means are employed in the mold for insert molding, the insert molded body, and the method for producing the insert molded body according to the present invention.
That is, the insert molding die according to claim 1 is communicated with the first cavity into which the first molten resin integrated with the insert part is injected, and the first melt. A first gate for injecting resin, and a second cavity in which a second molten resin is injected at a position opposed to the first cavity with the insert part interposed therebetween and having a smaller volume than the first cavity A movable body configured to be slidable in the direction of the second cavity and provided with a second gate that communicates with the inside of the second cavity and injects the second molten resin; and A drive unit that slides in the second cavity direction, and by sliding the movable body in the second cavity direction after the injection of the second molten resin, With a resin in the second cavity is configured to urge the insert part in the first cavity side, characterized in that is.
According to a second aspect of the present invention, there is provided an insert molding die according to the first aspect, wherein the side surface of the second cavity facing the insert part is provided with an inclined slope such that the width gradually decreases toward the lower part. It is formed.
According to a third aspect of the present invention, in the insert molding die according to the first or second aspect, the drive unit is a piston / cylinder mechanism provided above the movable body, and a rod of the piston is connected to the movable body. It is characterized by being.
According to a fourth aspect of the present invention, in the insert molding die according to any one of the first to third aspects, the first cavity is shaped so that a magnet rotor which is one component of a motor is molded. The insert part is a ring-shaped magnet.
An insert molded body according to a fifth aspect is characterized by being molded using the insert molding die according to any one of the first to fourth aspects.
According to a sixth aspect of the present invention, there is provided a method for manufacturing an insert molded body, injecting a first molten resin through a first gate into a first cavity formed on one side of an insert part, and sandwiching the insert part. On the other hand, a second molten resin is injected through a second gate into a second cavity formed with a smaller volume than the first cavity, and the second molten resin is injected after the second molten resin is injected. A movable body provided with a gate is slid in the direction of the second cavity, and the insert part is urged toward the first cavity with the resin in the second cavity to form an insert molded body. It is characterized by that.
According to a seventh aspect of the present invention, there is provided a method for manufacturing an insert molded body according to the sixth aspect, wherein the side surface of the second cavity facing the insert part is provided with an inclined slope so that the width gradually decreases toward the lower part. It is characterized by being formed.
According to an eighth aspect of the present invention, there is provided a method for manufacturing an insert molded body according to the sixth or seventh aspect, wherein the movable body is slid by a piston / cylinder mechanism in which the movable body and a piston rod are connected.
A method for manufacturing an insert molded body according to a ninth aspect is the method according to any one of the sixth to ninth aspects, wherein the first cavity is shaped so that a magnet rotor which is one component of a motor is molded, The insert component is a ring-shaped magnet, and the magnet rotor is manufactured by removing the molded body molded in the second cavity after injection molding.

  According to the present invention, after the injection of the second molten resin, the movable body provided with the second gate is slid in the direction of the second cavity, and the resin in the second cavity is inserted into the first cavity side. Since the component is configured to be urged, a gap is prevented from being generated between the resin in the second cavity (regardless of the solidified state, solidified state, or molten state) and the insert component. Even if the injection pressure of the first molten resin to be integrated is applied to the insert part, damage to the insert part can be prevented.

  Next, embodiments of the mold for insert molding, the method for manufacturing the insert molded body, and the insert molded body according to the present invention will be described. In the figure, symbol A indicates an insert molding die, symbol 1 indicates an upper die, and symbol 2 indicates a lower die.

  As the insert molding die A according to the present embodiment, a mold suitable for insert molding a magnet rotor W which is one component of a motor is exemplified. As shown in FIG. An upper mold 1 and a lower mold 2 are provided such that a substantially intermediate portion in the thickness direction of the substantially flange-shaped overhanging portion w2 to be formed is a parting line, and is configured to be mold-openable.

  The upper mold 1 includes a first upper mold 11, a movable body 12, a second upper mold 13, a third upper mold 14, and a drive unit 15.

  As shown in FIGS. 1 and 2, the first upper mold 11 has a lower surface of the first upper mold 11 so that a small-diameter cylindrical portion w3 is formed above the substantially flange-shaped protruding portion w2 that forms the magnet rotor W. Is formed, and a first gate 1b communicating with the first cavity 1a in which the magnet rotor W is formed is provided in the middle of the overhanging portion w2. In addition, four arc-shaped insertion grooves 1c into which a movable body 12, which will be described later, is slidably inserted are provided at predetermined positions outside the first gate 1b in the circumferential direction.

  The movable body 12 is formed in an arc shape having a required height that is slidably inserted so as to be accommodated in each of the insertion grooves 1c described above, and at the center of the movable body 12, the first cavity 1a side is formed. There is provided a second gate 1e communicating with the second cavity 1d through which a second molten resin wb (not limited to a molten state at the time of energization) for energizing the magnet w1 in the direction is injected.

  The second upper mold 13 is detachably attached to the upper surface of the first upper mold 11, and a connecting groove 1 f that connects the first gate 1 b and the second gate 1 e to the bottom surface of the second upper mold 13 is a substantially cross in plan view. A supply gate 1g through which molten resin from an injection molding machine flows is provided in the center of the communication groove 1f. Further, as shown in FIG. 2, guide holes 1h into which piston rods 1m described later are slidably inserted are positioned above the respective movable bodies 12 and are positioned in the respective movable bodies 12. Two each are provided so as to straddle the communication groove 1f.

  The third upper mold 14 is further detachably attached to the upper surface of the second upper mold 13, and is provided with a supply gate 1g communicating with the above-described supply gate 1g, and also communicates with each guide hole 1h. A cylinder hole 1i is provided. In addition, a hydraulic port 1j connected to a hydraulic device (not shown) is provided above the cylinder hole 1i (note that the drain side hydraulic port is not shown).

  The drive unit 15 includes a piston 1k that is slidably inserted into the cylinder hole 1i and a piston rod 1m that is connected to the piston 1k, and the tip of the piston rod 1m is movable. The movable body 12 is connected to the upper surface of the body 12 and is slid back and forth in the direction of the second cavity 1d described later by the hydraulic pressure from the hydraulic device.

  The lower mold 2 is formed with a large-diameter cylindrical portion w4 below the substantially flange-shaped protruding portion w2 that forms the magnet rotor W, and an insert portion 1n that is inserted so that the magnet w1 is suspended from the outer periphery of the protruding portion w2. A region where the magnet rotor W is molded with the first upper die 11 and the lower die 2 is the first cavity 1a.

  In the second cavity 1d, the upper portion of the region extending in the outward direction from the insert portion 1n is formed with a required width in which the movable body 12 can be inserted, and faces the magnet w1, which is an insert component. An inclined slope is formed from the middle so that the side surface 2a gradually becomes narrower toward the lower portion, and the second cavity 1d is defined by inserting the magnet w1.

  The second cavity 1d is formed to have a smaller volume than the first cavity 1a, and the second molten resin wb injected into the second cavity 1d is contained in the first cavity 1a. Solidification proceeds faster than the first molten resin wa injected into the container.

  Next, a method for manufacturing a magnet rotor W (insert molded body) using the insert molding die A according to the present embodiment configured as described above will be described. The description will proceed on the assumption that the insert molding die A is set in the injection molding machine, the hydraulic port 1j is connected to the hydraulic device, and all the pre-settings for insert molding are completed.

First, after the mold is opened, the magnet w1 is set on the insert portion 1n of the lower mold 2 and then the mold is clamped.
When the mold clamping is completed, the molten resin is immediately poured into the supply gate 1g. The molten resin branches into the first molten resin wa and the second molten resin wb via the first gate 1b and the second gate 1e, and the first molten resin wa is in the first cavity 1a. The second molten resin wb is injected into the second cavity 1d.

When the inside of the second cavity 1d is filled with the second molten resin wb, the movable body 12 is slid in the direction of the second cavity 1d as shown in FIG.
At this time, if the resin in the second cavity 1d is solidified, the slanted side surface 2a facing the insert part acts so that the solidified resin moves to the magnet w1 side, and the side surface of the magnet w1 Press. Further, when solidified during solidification, the side surface of the magnet w1 is pressed according to the Pascal principle.

  When pressing of the side surface of the magnet w1 is started with the resin in the second cavity 1d, the first molten resin wa is being injected into the first cavity 1a, and the resin in the magnet w1 and the second cavity 1d In this case, even if the injection pressure of the first molten resin wa integrated with the magnet w1 is loaded on the magnet w1, damage to the magnet w1 is prevented.

  Next, when the first molten resin wa is completed in the first cavity 1a and solidified, the movable body 12 is returned to the original position by the hydraulic device, the mold is opened, and the magnet rotor W is removed from the mold. (See FIG. 4).

And the molded object shape | molded by the 2nd cavity 1d is removed so that it may peel from the magnet w1, and the spur gear G is integrated in the small diameter cylinder part w3, and manufacture of the magnet rotor W which is an insert molded object is complete | finished (FIG. 5).
The magnet rotor W (insert molded body) produced by this mold and manufacturing method has a high yield and has a stronger adhesion between the resin and the insert parts than the conventional one.

  Although the present embodiment has been described above, the above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto and does not depart from the gist thereof. Various modifications can be made within the range.

It is a longitudinal cross-sectional view of the metal mold | die for insert molding concerning this Embodiment. FIG. 2 is a schematic perspective view of the same. FIG. 6 is an operation explanatory diagram in a state where the movable body is slid and the magnet is biased. It is a longitudinal cross-sectional view of a mold open state similarly. FIG. 2 is a longitudinal sectional view of the magnet rotor.

Explanation of symbols

A insert mold W magnet rotor w1 magnet w2 overhanging portion w3 small diameter cylindrical portion w4 large diameter cylindrical portion wa first molten resin wb second molten resin 1 upper mold 11 first upper mold 12 movable body 13 second upper Mold 14 Third upper mold 15 Drive unit 1a First cavity 1b First gate 1c Insertion groove 1d Second cavity 1e Second gate 1f Connection groove 1g Supply gate 1h Guide hole 1i Cylinder hole 1j Hydraulic port 1k Piston 1m Piston rod 1n Insert 2 Lower mold 2a Side G Spur gear

Claims (9)

A first cavity into which a first molten resin integrated with an insert part is injected;
A first gate that communicates with the inside of the first cavity and injects the first molten resin;
A second cavity that is formed with a smaller volume than the first cavity and is injected with a second molten resin at a position facing the first cavity across the insert part;
A movable body configured to be slidable in the direction of the second cavity and provided with a second gate that communicates with the inside of the second cavity and injects the second molten resin;
A drive unit that slides the movable body toward the second cavity,
By sliding the movable body in the direction of the second cavity after the injection of the second molten resin, the insert component is biased toward the first cavity with the resin in the second cavity. The mold for insert molding characterized by being comprised in this.   2. The insert molding according to claim 1, wherein a side surface of the second cavity facing the insert part is formed with an inclined slope that gradually becomes narrower toward a lower portion. Mold. The drive unit is a piston / cylinder mechanism provided above the movable body,
The insert molding die according to claim 1 or 2, wherein a rod of the piston is connected to the movable body.   The first cavity is shaped so that a magnet rotor, which is one component of a motor, is formed, and the insert part is a ring-shaped magnet. The mold for insert molding according to any one of the above.   An insert molded body, which is molded using the insert molding die according to any one of claims 1 to 4. A first molten resin is injected through a first gate into a first cavity formed on one side with an insert part interposed therebetween, and formed on the other side with a smaller volume than the first cavity with the insert part interposed therebetween. A second molten resin is injected into the second cavity through the second gate;
After the injection of the second molten resin, the movable body provided with the second gate is slid in the direction of the second cavity, and the insert part is moved with the resin in the second cavity to the first cavity. A method for producing an insert molded body, characterized in that the insert molded body is molded by urging to the side.   7. The insert molded body according to claim 6, wherein a side surface of the second cavity facing the insert part is formed with an inclined slope that gradually becomes narrower toward a lower part. Method.   8. The method of manufacturing an insert molded body according to claim 6, wherein the movable body is slid by a piston / cylinder mechanism in which the movable body and a rod of a piston are connected. The first cavity is shaped so that a magnet rotor which is one component of the motor is molded,
The insert part is a ring-shaped magnet,
The method for manufacturing an insert molded body according to any one of claims 6 to 9, wherein the magnet rotor is manufactured by removing the molded body molded in the second cavity after injection molding.

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