JPH09187822A - Mold assembly with ejecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the poor actuation of an ejector pin for forming a gas vent and the breakage and wear of a cavity forming surface with the ejector pin from occurring. SOLUTION: A through hole 47, through which an ejector pin 43 passes, has a small diameter part 48 at the end on a cavity 23 side. The ejector pin 43 has a tip fitting part 51, the diameter of which is slightly smaller than that of the small diameter part 48, at its tip part and, at the same time, a groove 52 adjacent to the tip fitting part 51. The groove 52 is a V-shape groove. Even if the ejector pin 43 strikes the peripheral part of the through hole 47 at a cavity forming surface 72, no large shock develops, since the striking portion of the ejector pin is a tapered part 53.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die device with an ejection mechanism in which a gas vent is formed by utilizing the ejection mechanism.

[0002]

2. Description of the Related Art For example, in a mold apparatus used for injection molding of resin, there is a mold apparatus in which a molded product is ejected and ejected by an ejection pin when the die is opened. Further, there is one in which a gas vent is formed by utilizing this protruding pin to release gas from the inside of the cavity at the time of filling the resin.
FIG. 4 shows an example of a conventional mold apparatus of this type.
In the figure, reference numeral 1 denotes a fixed mold, which forms a product-shaped cavity 2 between it and a movable mold (not shown). 3 is a protruding pin, and this protruding pin 3 is
It penetrates through the linear through hole 4 formed in the fixed mold 1 and projects the product 5 when the mold is opened. The through hole 4
Has a small-diameter portion 6 on the cavity 2 side,
The other portion is a large-diameter portion 7 having a diameter slightly larger than the small-diameter portion 6, and a step portion 8 is provided between the small-diameter portion 6 and the large-diameter portion 7. In addition, the protruding pin 3 is provided in the cavity 2
The leading end portion on the side is a leading end fitting portion 9 that substantially fits into the through hole 4, and a groove 10 for gas vent having a smaller diameter is formed adjacent to the leading end fitting portion 9. . In the conventional mold device, the concave groove 10 has protruding sides 3 on both sides.
It was formed on a plane orthogonal to the axial direction of. Further, on the outer peripheral surface of the protrusion pin 3, a flat surface portion 11 for reducing gas flow resistance is formed at a part of the position on the side opposite to the cavity 2 with respect to the concave groove 10. The tip fitting portion 9
Is at least partially smaller than the diameter of the small diameter portion 6 of the through hole 4 by about 0.01 to 0.1 mm. On the other hand, the concave groove 10 has a depth of, for example, about 0.5 to 1 mm and an axial length of, for example, about 3 mm. In the drawing,
The depths of the groove 10 and the step portion 8 are exaggerated.

At the time of molding, as the cavity 2 is filled with the resin, the gas and air of the resin in the cavity 2 are mixed with the tip fitting portion 9 of the ejection pin 3 and the small diameter portion 6 of the through hole 4. Between the peripheral surface and the protruding pin 3
Exit through the groove 10 of. After the resin filled in the cavity 2 is solidified, the mold is opened and the molded product is taken out. At this time, as shown by the chain line,
The ejection pin 3 ejects the product to release it from the fixed mold 1.

[0004]

However, in the above-mentioned conventional mold apparatus, since the outer peripheral surface of the protrusion pin 3 and the side surface of the concave groove 10 for gas vent are orthogonal to each other, the following problems occur. . First, due to factors such as dimensional error and thermal deformation, the side surface of the concave groove 10 on the cavity 2 side hits the cavity forming surface 12 of the fixed mold 1, and the side surface of the concave groove 10 on the side opposite to the cavity 2 passes through the fixed mold 1. If it hits the stepped portion 8 of the hole 4, the ejecting pin 3 may malfunction, and the ejecting pin 3 and the fixed die 1 may be easily damaged or worn. In particular, the cavity forming surface 12 is a portion that directly affects the product 5, and if damage or wear occurs around the through-hole 4, molding defects such as burrs are generated in the product 5. Further, in manufacturing, the ejecting pin 3 is required to have high accuracy, but in the concave groove 10 having the above-described shape, jig grinding must be performed to form the concave groove 10 in the ejecting pin 3. , Costly.

The present invention is intended to solve such problems, and provides a die device with an ejection mechanism capable of preventing malfunction of an ejection pin forming a gas vent, damage to a cavity forming surface, and abrasion. The purpose is to

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 has a plurality of molds which are opened and closed to form a cavity between them when the molds are closed, and a mold incorporated in the molds. An ejecting mechanism for ejecting the molding material in the cavity at the time of opening, and the ejecting mechanism has an ejecting pin penetrating a through hole formed in the mold, and the ejecting pin between the ejecting pin and the peripheral surface of the through hole is provided. In a die device with an ejection mechanism in which a gas vent is formed to allow gas to escape from the inside of the cavity by a gap, the ejection pin has a tip fitting portion having substantially the same cross-sectional shape as the through hole on the cavity side, and the tip fitting portion There is a groove for gas venting on the adjacent peripheral surface, and this groove has a tapered portion whose cross-sectional shape becomes smaller in the direction away from the cavity at the part connected to the tip fitting part. Than it is.

At the time of molding, the molding material is filled in the cavity with the mold closed. At this time, the gas in the cavity escapes to the outside of the cavity through the gap between the tip fitting portion of the ejection pin and the peripheral surface of the through hole and the groove on the peripheral surface of the ejection pin. Further, the mold opening is performed after the molding material filled in the cavity is solidified, and at this time, the ejection pin ejects the molding material in the cavity to release from the mold. After that, the ejector pin returns to its original position.At this time, even if the portion of the cavity of the mold body that is connected to the tip fitting portion of the concave groove of the ejector pin hits the periphery of the through hole, this portion Has a tapered section with a smaller cross-sectional shape in the direction away from the cavity, so a large impact does not occur, the ejector pin malfunctions, and the cavity forming surface is damaged.
No wear will occur.

According to a second aspect of the present invention, in the die device with an ejection mechanism according to the first aspect, the angle formed by the tapered portion with respect to the axial direction of the ejection pin is 0 ° 30 'to 30 °. If this angle is 30 ° or more, the impact when the portion of the recessed groove of the protrusion pin connected to the tip fitting portion hits the cavity forming surface is not sufficiently weak.
On the other hand, if it is 0 ° 30 'or less, it becomes difficult to form a gas vent of a sufficient size. Therefore, the taper angle of 0 ° 30 'to 30 ° is suitable.

According to a third aspect of the present invention, in the die device with an ejecting mechanism according to the first or second aspect, the through hole has a narrowed portion having a smaller cross-sectional area than other portions at an end portion on the cavity side, The concave groove is formed by tapering a portion on the side opposite to the tip fitting portion toward the cavity side, the cross-sectional shape of which becomes smaller. With this configuration, when the ejection pin ejects, even if the stepped portion to the narrowed portion in the through hole of the mold body hits the portion on the opposite side of the tip fitting portion in the concave groove, this portion Due to the taper portion having a smaller cross-sectional shape toward the cavity side, a large impact is not generated, and the malfunction of the ejection pin does not occur.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a die device with an ejection mechanism according to the present invention will be described below with reference to FIGS. 21 is a fixed mold that is a mold body, 22 is a movable mold that is another mold body, and these fixed mold 21 and movable mold 22 move in the left-right direction in the drawing (hereinafter, referred to as mold opening and closing direction) to open and close, The product-shaped cavities 23 are formed between each other when the mold is closed.

The fixed mold 21 has a fixed mold plate 26 which forms a cavity 23, and a first fixed side receiving plate 27 which is fixed to the rear side of the fixed mold plate 26 opposite to the movable mold 22. A spacer block 28 is provided on the back side of the first fixed side receiving plate 27.
The second fixed side receiving plate 29 fixed via the
The fixed side receiving plate 29 is provided with a fixed side mounting plate 31 fixed on the back side via a spacer block 30. And, this fixed side mounting plate 31 has a locate ring
A sprue bush 33 is fixed together with 32. The sprue bush 33 penetrates the second fixed-side receiving plate 29 and is connected to a manifold 34 provided between the second fixed-side receiving plate 29 and the first fixed-side receiving plate 27. ing. The sprue 35 formed in the sprue bush 33 communicates with the runner 36 formed in the manifold 34. In addition, the manifold 34 has its runner 36
The gate opening / closing devices 37 are connected to the final branching portions of the gate opening / closing devices 37, and the gates 38 at the tips of the gate opening / closing devices 37 face the cavities 23, respectively.

The fixed die 21 has a fixed side ejection mechanism 41 incorporated therein. Here, the configuration of the fixed-side protrusion mechanism 41 will be described. A fixed-side protruding plate 42 is provided between the second fixed-side receiving plate 29 and the fixed-side mounting plate 31 so as to be movable in the mold opening / closing direction. The fixed-side protruding plate 42 is provided with an elongated cylindrical protruding pin 43 whose axial direction coincides with the mold opening / closing direction so as to protrude toward the cavity 23. The protruding pin 43 is provided with through holes 44, 45, 4 formed in the second fixed side receiving plate 29, the manifold 34, the first fixed side receiving plate 27 and the fixed side template 26, respectively.
The tip penetrates through 6 and 47 and faces the cavity 23. Through holes 44, 4
5, 46, 47 have a circular cross-section, but eject pin 4
In order to reduce the sliding resistance of 3, the tip end facing the cavity 23 is a small diameter portion 48 which is a narrowed portion, while the other portions have a diameter slightly larger than the small diameter portion 48. A large portion 49 is formed, and a step 50 is formed between the small diameter portion 48 and the large diameter portion 49.
There is.

Further, the protrusion pin 43 forms a gas vent by a gap between the protrusion pin 43 and the peripheral surface of the through hole 47. Therefore, the tip of the protrusion pin 43 on the side of the cavity 23 has almost the same cross-sectional shape as the small diameter portion 48 of the through hole 47, but the diameter is 0.01 to 0.1 mm at least partially than the small diameter portion 48. It is a small tip fitting portion 51. A concave groove 52 that forms a gas reservoir at the time of gas venting is formed on the peripheral surface of the protruding pin 43 adjacent to the tip fitting portion 51. The concave groove 52 is a V-shaped groove, and the tip fitting portion 51 side is a first tapered portion 53 whose diameter decreases in the direction away from the cavity 23, and the opposite side is the cavity 23 side. The second taper portion 54 has a diameter that decreases toward the bottom. In particular, the first taper portion 53
The angle α formed by the generatrix with respect to the axial direction of the protruding pin 43 is 0 ° 30 'to 30 °, preferably 1 ° to 5 °.

The movable die 22 includes a movable side mold plate 61 forming a cavity 23, a movable side receiving plate 62 fixed to the rear side of the movable side mold plate 61 opposite to the fixed mold 21, and the movable side mold plate 61. A movable side mounting plate 64 fixed via a spacer block 63 is provided on the back side of the side receiving plate 62. Then, the movable die 22 has a movable side ejection mechanism 65 incorporated therein. The movable side ejecting mechanism 65 has a movable side ejecting plate 66 provided between the movable side receiving plate 62 and the movable side mounting plate 64 so as to be movable in the mold opening / closing direction. A protruding pin 67 whose axial direction coincides with the mold opening / closing direction is provided so as to protrude toward the cavity 23.
The protruding pin 67 penetrates through holes 68 and 69 formed in the movable side receiving plate 62 and the movable side template 61, respectively, and the tip faces the cavity 23.

Next, the operation of the above configuration will be described. At the time of molding, in a state where the fixed mold 21 and the movable mold 22 are closed, a molten resin as a molding material is injected from the nozzle of the injection molding machine to the sprue 35. This resin is
The sprue 35 passes through the runner 36 of the manifold 34 and the gate opening / closing device 37, and then flows into the cavity 23 from the gate 38. When the cavity 23 is filled with the resin in this way, the gas and air of the resin in the cavity 23 are separated into the tip fitting portion 51 of the protrusion pin 43 and the small diameter portion 48 of the through hole 47.
To the outside of the mold device through the gap between the outer peripheral surface of the mold and the concave groove 52 of the protruding pin 43, and further through the through hole 47 or another through hole formed through the fixed mold 21. Get out.

After the resin filled in the cavity 23, that is, the product 71 is cooled and solidified, the fixed mold 21 and the movable mold 21
22 and 22 are opened. At this time, first, the fixed side protruding plate 42
Is pushed by the ejection rod of the injection molding machine and moves relatively to the movable mold 22 with respect to the fixed-side mold plate 26 and the like. This allows the eject pin 43 to eject the product 71,
Release from 21. Then, the movable-side protruding plate 65 is pushed by the protruding rod of the injection molding machine to move the movable-side template 61.
Move to the fixed mold 21 relative to. As a result, the ejector pin 67 ejects the product 71 and separates it from the movable mold 22. Then, the mold is closed again, and the above molding cycle is repeated.

At the time of mold closing, when the protruding pin 43 protruding as described above returns to the original position, the through hole is caused for some reason.
If 47 and eject pin 43 are misaligned,
At the peripheral portion of the through hole 47 in the cavity forming surface 72 of the fixed-side template 27, the tip fitting portion 51 in the concave groove 52 of the protrusion pin 43.
The part connected to can be hit. However, this part is the first part whose diameter decreases in the direction away from the cavity 23.
Since it is the taper portion 53, no large impact occurs. Therefore, malfunction of the ejection pin 43 does not occur, and damage or wear does not occur in the peripheral portion of the through hole 47 in the cavity forming surface 72 forming the product 71. As a result, molding defects such as burrs on the product 71 can be prevented. Of course, the protruding pin 43 is damaged,
Wear can also be prevented.

If the angle α formed by the generatrix of the first taper portion 53 with respect to the axial direction of the protrusion pin 43 is 30 ° or more, the portion of the protrusion groove 43 of the protrusion pin 43 connected to the tip fitting portion 51. The impact on the cavity forming surface 72 does not become sufficiently weak. Also, in order to secure the strength of the protrusion pin 43, the taper angle α should not be too large. On the other hand, if it is 0 ° 30 'or less, it becomes difficult to form a gas vent of a sufficient size. Therefore, the taper angle α is preferably 0 ° 30 'to 30 °. Further, in order to sufficiently weaken the impact, the taper angle α should be 5 ° or less.

Further, when the ejecting pin 43 is ejected, the tip fitting portion in the concave groove 52 is formed in the step portion 50 in the through hole 47.
Even if the portion on the opposite side to 51 hits, this portion becomes the second taper portion 54 whose diameter decreases toward the cavity 23 side.
Therefore, a large impact is not generated, and the malfunction of the ejection pin 43 does not occur. Although the concave groove 52 is a V-shaped groove in the above-described embodiment, the collision with the fixed-side mold plate 26 is a problem because the concave groove 52 has a relatively large diameter on both ends. Only both ends of the groove 52 may be tapered. Accordingly, even if the axial length of the recessed groove 52 is short, the volume of the recessed groove 52 can be secured as much as necessary for the gas vent. However, if the concave groove 52 is formed into a V-shaped groove, the protrusion pin 52 can be easily and quickly formed by using a grinding wheel 76 having an inverted shape of the concave groove 52 as shown in FIG. 3 without performing jig grinding. Can be manufactured at low cost.

Further, in the above-described embodiment, an example in which the present invention is applied to the ejecting pin 43 of the ejecting mechanism 41 incorporated in the fixed die 21 has been described, but the present invention is of course applicable to the ejecting mechanism incorporated in the movable die. It can also be applied to protruding pins.

[0021]

According to the first aspect of the present invention, in the die device with an ejection mechanism in which the gas vent is formed by the gap between the ejection pin and the peripheral surface of the through hole, the ejection pin is
The cavity has a tip fitting part that has almost the same cross-sectional shape as the through hole, and also has a groove on the peripheral surface adjacent to the tip fitting part. Since the taper part has a smaller cross-sectional shape in the direction away from it, even if the cavity forming surface of the mold body hits the part connected to the tip fitting part of the concave groove of the ejection pin, the ejection pin malfunctions. Not with
The cavity forming surface or the like is not damaged or worn, and therefore, defective molding such as burrs in the product can be prevented.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the angle formed by the tapered portion with respect to the axial direction of the protrusion pin is 0 ° 30 'to 30 °, the gas vent of the gas vent is While ensuring the size, it is possible to reliably prevent malfunction of the protruding pin, damage to the cavity forming surface, and abrasion. According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, the through hole has a narrowed portion having a smaller cross-sectional area than the other portions at the end portion on the cavity side, whereas the concave groove The taper part of the side opposite to the tip fitting part has a smaller cross-sectional shape toward the cavity side, so that the tip fitting part in the concave groove at the step part to the narrowed part in the through hole of the mold body. Even if the part on the opposite side hits, malfunction of the ejector pin does not occur.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view near an ejection pin showing an embodiment of a die device with an ejection mechanism of the present invention.

FIG. 2 is a sectional view of the whole of the same.

FIG. 3 is a side view showing a method for manufacturing the same protruding pin.

FIG. 4 is a cross-sectional view near an ejection pin showing an example of a conventional die device with an ejection mechanism.

[Explanation of symbols] 21 Fixed type (mold body) 22 Movable type (mold body) 23 Cavity 41 Fixed side ejection mechanism (ejection mechanism) 43 Ejection pin 47 Through hole 48 Small diameter portion (narrowed portion) 51 Tip fitting portion 52 Groove 53 First tapered portion 54 Second tapered portion α Angle

[Procedure amendment]

[Submission date] January 17, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of Invention] Mold device with ejection mechanism

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die device with an ejection mechanism in which a gas vent is formed by utilizing the ejection mechanism.

[0002]

2. Description of the Related Art For example, in a mold apparatus used for injection molding of resin, there is a mold apparatus in which a molded product is ejected and ejected by an ejection pin when the die is opened. Further, there is one in which a gas vent is formed by utilizing this protruding pin to release gas from the inside of the cavity at the time of filling the resin.

FIG. 4 shows an example of a conventional mold apparatus of this type. In the figure, reference numeral 1 denotes a fixed mold, which forms a product-shaped cavity 2 between it and a movable mold (not shown). Reference numeral 3 denotes an ejector pin, which penetrates a linear through hole 4 formed in the fixed mold 1 and ejects the product 5 when the mold is opened.
The through-hole 4 has a small-diameter portion 6 on the cavity 2 side, but has a large-diameter portion 7 having a diameter slightly larger than the small-diameter portion 6 at the other portions. There is a step portion 8 between the portion 6 and the large-diameter portion 7. Further, the protrusion pin 3 has a tip fitting portion 9 whose tip on the cavity 2 side almost fits into the through hole 4 and is adjacent to the tip fitting portion 9 for a gas vent having a smaller diameter. The concave groove 10 is formed.
In the conventional mold device, the concave groove 10 is formed in a plane in which both side surfaces are orthogonal to the axial direction of the protruding pin 3.
Further, on the outer peripheral surface of the protrusion pin 3, a flat surface portion 11 for reducing the flow resistance of gas is formed at a part of the position on the side opposite to the cavity 2 with respect to the concave groove 10. The diameter of the tip fitting portion 9 is at least partially smaller than the diameter of the small diameter portion 6 of the through hole 4 by about 0.01 to 0.1 mm. On the other hand, the groove 10 has a depth of, for example, about 0.5 to 1 mm,
The length in the axial direction is, for example, about 3 mm. In the drawings, the depths of the concave groove 10 and the step portion 8 are exaggerated.

At the time of molding, as the cavity 2 is filled with the resin, the gas and air of the resin in the cavity 2 are mixed with the tip fitting portion 9 of the protrusion pin 3 and the small diameter portion 6 of the through hole 4. Between the peripheral surface and the protruding pin 3
Exit through the groove 10 of. After the resin filled in the cavity 2 is solidified, the mold is opened and the molded product is taken out. At this time, as shown by the chain line,
The ejection pin 3 ejects the product to release it from the fixed mold 1.

[0005]

However, in the above-mentioned conventional mold apparatus, since the outer peripheral surface of the protrusion pin 3 and the side surface of the concave groove 10 for gas vent are orthogonal to each other, the following problems occur. . First, due to factors such as dimensional error and thermal deformation, the side surface of the concave groove 10 on the cavity 2 side hits the cavity forming surface 12 of the fixed mold 1, and the side surface of the concave groove 10 on the side opposite to the cavity 2 passes through the fixed mold 1. If it hits the stepped portion 8 of the hole 4, the ejecting pin 3 may malfunction, and the ejecting pin 3 and the fixed die 1 may be easily damaged or worn. In particular, the cavity forming surface 12 is a portion that directly affects the product 5, and if damage or wear occurs around the through-hole 4, molding defects such as burrs are generated in the product 5. Further, in manufacturing, the ejecting pin 3 is required to have high accuracy, but in the concave groove 10 having the above-described shape, jig grinding must be performed to form the concave groove 10 in the ejecting pin 3. , Costly.

The present invention is intended to solve such a problem, and provides a die device with an ejection mechanism capable of preventing malfunction of an ejection pin forming a gas vent, damage to a cavity forming surface, and abrasion. The purpose is to

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 has a plurality of molds which are opened and closed to form a cavity between them when the molds are closed, and a mold incorporated in the molds. An ejecting mechanism for ejecting the molding material in the cavity at the time of opening, and the ejecting mechanism has an ejecting pin penetrating a through hole formed in the mold, and the ejecting pin between the ejecting pin and the peripheral surface of the through hole is provided. In a die device with an ejection mechanism in which a gas vent is formed to allow gas to escape from the inside of the cavity by a gap, the ejection pin has a tip fitting portion having substantially the same cross-sectional shape as the through hole on the cavity side, and the tip fitting portion has a groove for the gas vent to adjacent peripheral surface, the groove is at least the lead to the tip fitting portion is first reduced cross-sectional shape toward the direction away from the cavity It is intended to include the supermarkets part.

At the time of molding, the molding material is filled in the cavity with the mold closed. At this time, the gas in the cavity escapes to the outside of the cavity through the gap between the tip fitting portion of the ejection pin and the peripheral surface of the through hole and the groove on the peripheral surface of the ejection pin. Further, the mold opening is performed after the molding material filled in the cavity is solidified, and at this time, the ejection pin ejects the molding material in the cavity to release from the mold. After that, the ejector pin returns to its original position.At this time, even if the portion of the cavity of the mold body that is connected to the tip fitting portion of the concave groove of the ejector pin hits the periphery of the through hole, this portion Is a first taper part having a smaller cross-sectional shape in the direction away from the cavity, a large impact is not generated, the ejector pin malfunctions, the cavity forming surface is damaged, etc. No wear will occur.

According to a second aspect of the present invention, in the die device with an ejection mechanism according to the first aspect, the angle formed by the first taper portion with respect to the axial direction of the ejection pin is 0 ° 30 'to 30 °. Is.

When the angle is 30 ° or more, the impact when the portion of the recessed groove of the protrusion pin connected to the tip fitting portion hits the cavity forming surface is not sufficiently weak. On the other hand, if it is 0 ° 30 'or less, it becomes difficult to form a gas vent of a sufficient size. Therefore, the taper angle of 0 ° 30 'to 30 ° is suitable.

According to a third aspect of the present invention, in the die device with an ejection mechanism according to the first or second aspect, the through hole has a narrowed portion having a smaller cross-sectional area than other portions at an end portion on the cavity side, The groove is connected to at least the tip fitting portion.
The diameter decreases as the part moves away from the cavity.
That a first tapered portion, in which the opposite side portion and the tip fitting portion constituted from the second tapered <br/> over portion decreases in cross-sectional shape toward the keys <br/> Yabiti side.

With this configuration, when the ejecting pin ejects, even if the stepped portion to the narrowed portion in the through hole of the mold body hits the portion of the concave groove opposite to the tip fitting portion, This part is the second taper part whose cross-sectional shape decreases toward the cavity side,
No big impact is generated, and the malfunction of the ejector pin does not occur.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a die device with an ejection mechanism according to the present invention will be described below with reference to FIGS. 21 is a fixed mold that is a mold body, 22 is a movable mold that is another mold body, and these fixed mold 21 and movable mold 22 move in the left-right direction in the drawing (hereinafter, referred to as mold opening and closing direction) to open and close, The product-shaped cavities 23 are formed between each other when the mold is closed.

The fixed mold 21 has a fixed side mold plate 26 forming a cavity 23, a first fixed side receiving plate 27 fixed to the rear side of the fixed side mold plate 26 opposite to the movable mold 22, A spacer block 28 is provided on the back side of the first fixed side receiving plate 27.
The second fixed side receiving plate 29 fixed via the
The fixed side receiving plate 29 is provided with a fixed side mounting plate 31 fixed on the back side via a spacer block 30. And, this fixed side mounting plate 31 has a locate ring
A sprue bush 33 is fixed together with 32. The sprue bush 33 penetrates the second fixed-side receiving plate 29 and is connected to a manifold 34 provided between the second fixed-side receiving plate 29 and the first fixed-side receiving plate 27. ing. The sprue 35 formed in the sprue bush 33 communicates with the runner 36 formed in the manifold 34. In addition, the manifold 34 has its runner 36
The gate opening / closing devices 37 are connected to the final branching portions of the gate opening / closing devices 37, and the gates 38 at the tips of the gate opening / closing devices 37 face the cavities 23, respectively.

The fixed die 21 has a fixed side ejection mechanism 41 incorporated therein. Here, the configuration of the fixed-side protrusion mechanism 41 will be described. A fixed-side protruding plate 42 is provided between the second fixed-side receiving plate 29 and the fixed-side mounting plate 31 so as to be movable in the mold opening / closing direction. The fixed-side protruding plate 42 is provided with an elongated cylindrical protruding pin 43 whose axial direction coincides with the mold opening / closing direction so as to protrude toward the cavity 23. The protruding pin 43 is provided with through holes 44, 45, 4 formed in the second fixed side receiving plate 29, the manifold 34, the first fixed side receiving plate 27 and the fixed side template 26, respectively.
The tip penetrates through 6 and 47 and faces the cavity 23. Through holes 44, 4
5, 46, 47 have a circular cross-section, but eject pin 4
In order to reduce the sliding resistance of 3, the tip end facing the cavity 23 is a small diameter portion 48 which is a narrowed portion, while the other portions have a diameter slightly larger than the small diameter portion 48. A large portion 49 is formed, and a step 50 is formed between the small diameter portion 48 and the large diameter portion 49.
There is.

Further, the protruding pin 43 forms a gas vent by the gap between the protruding pin 43 and the peripheral surface of the through hole 47. Therefore, the tip of the protrusion pin 43 on the side of the cavity 23 has almost the same cross-sectional shape as the small diameter portion 48 of the through hole 47, but the diameter is 0.01 to 0.1 mm at least partially than the small diameter portion 48. It is a small tip fitting portion 51. A concave groove 52 that forms a gas reservoir at the time of gas venting is formed on the peripheral surface of the protruding pin 43 adjacent to the tip fitting portion 51. The concave groove 52 is a V-shaped groove, and the tip fitting portion 51 side is a first tapered portion 53 whose diameter decreases in the direction away from the cavity 23, and the opposite side is the cavity 23 side. The second taper portion 54 has a diameter that decreases toward the bottom. In particular, the first taper portion 53
The angle α formed by the generatrix with respect to the axial direction of the protruding pin 43 is 0 ° 30 'to 30 °, preferably 1 ° to 5 °.

The movable die 22 has a movable side mold plate 61 forming the cavity 23, a movable side receiving plate 62 fixed to the back side of the movable side mold plate 61 opposite to the fixed mold 21, and the movable side mold plate 62. A movable side mounting plate 64 fixed via a spacer block 63 is provided on the back side of the side receiving plate 62. Then, the movable die 22 has a movable side ejection mechanism 65 incorporated therein. The movable side ejecting mechanism 65 has a movable side ejecting plate 66 provided between the movable side receiving plate 62 and the movable side mounting plate 64 so as to be movable in the mold opening / closing direction. A protruding pin 67 whose axial direction coincides with the mold opening / closing direction is provided so as to protrude toward the cavity 23.
The protruding pin 67 penetrates through holes 68 and 69 formed in the movable side receiving plate 62 and the movable side template 61, respectively, and the tip faces the cavity 23.

Next, the operation of the above configuration will be described. At the time of molding, in a state where the fixed mold 21 and the movable mold 22 are closed, a molten resin as a molding material is injected from the nozzle of the injection molding machine to the sprue 35. This resin is
The sprue 35 passes through the runner 36 of the manifold 34 and the gate opening / closing device 37, and then flows into the cavity 23 from the gate 38. When the cavity 23 is filled with the resin in this way, the gas and air of the resin in the cavity 23 are separated into the tip fitting portion 51 of the protrusion pin 43 and the small diameter portion 48 of the through hole 47.
To the outside of the mold device through the gap between the outer peripheral surface of the mold and the concave groove 52 of the protruding pin 43, and further through the through hole 47 or another through hole formed through the fixed mold 21. Get out.

After the resin filled in the cavity 23, that is, the product 71 is cooled and solidified, the fixed mold 21 and the movable mold 21
22 and 22 are opened. At this time, first, the fixed side protruding plate 42
Is pushed by the ejection rod of the injection molding machine and moves relatively to the movable mold 22 with respect to the fixed-side mold plate 26 and the like. This allows the eject pin 43 to eject the product 71,
Release from 21. Then, the movable-side protruding plate 65 is pushed by the protruding rod of the injection molding machine to move the movable-side template 61.
Move to the fixed mold 21 relative to. As a result, the ejector pin 67 ejects the product 71 and separates it from the movable mold 22. Then, the mold is closed again, and the above molding cycle is repeated.

At the time of mold closing, when the protruding pin 43 protruding as described above returns to its original position, the through hole is caused for some reason.
If 47 and eject pin 43 are misaligned,
At the peripheral portion of the through hole 47 in the cavity forming surface 72 of the fixed-side template 27, the tip fitting portion 51 in the concave groove 52 of the protrusion pin 43.
The part connected to can be hit. However, this part is the first part whose diameter decreases in the direction away from the cavity 23.
Since it is the taper portion 53, no large impact occurs. Therefore, malfunction of the ejection pin 43 does not occur, and damage or wear does not occur in the peripheral portion of the through hole 47 in the cavity forming surface 72 forming the product 71. As a result, molding defects such as burrs on the product 71 can be prevented. Of course, the protruding pin 43 is damaged,
Wear can also be prevented.

If the angle α formed by the generatrix of the first taper portion 53 with respect to the axial direction of the protrusion pin 43 is 30 ° or more, the portion of the recessed groove 52 of the protrusion pin 43 connected to the tip fitting portion 51. The impact on the cavity forming surface 72 does not become sufficiently weak. Also, in order to secure the strength of the protrusion pin 43, the taper angle α should not be too large. On the other hand, if it is 0 ° 30 'or less, it becomes difficult to form a gas vent of a sufficient size. Therefore, the taper angle α is preferably 0 ° 30 'to 30 °. Further, in order to sufficiently weaken the impact, the taper angle α should be 5 ° or less.

Further, when the ejecting pin 43 is ejected, the tip fitting portion in the concave groove 52 is formed in the step portion 50 in the through hole 47.
Even if the portion on the opposite side to 51 hits, this portion becomes the second taper portion 54 whose diameter decreases toward the cavity 23 side.
Therefore, a large impact is not generated, and the malfunction of the ejection pin 43 does not occur.

Although the concave groove 52 is a V-shaped groove in the above-described embodiment, the collision with the fixed-side mold plate 26 becomes a problem when the concave groove 52 has a relatively large diameter on both ends. Therefore, only the both ends of the groove 52 may be tapered. Accordingly, even if the axial length of the recessed groove 52 is short, the volume of the recessed groove 52 can be secured as much as necessary for the gas vent. However, the groove 52 is
If the groove is formed into a groove, without using jig grinding, as shown in FIG. 3, a grinding wheel 76 having an inverted shape of the groove 52 is used.
The ejection pin 52 can be easily manufactured in a short time, and the cost can be reduced.

Further, in the above-described embodiment, an example in which the present invention is applied to the ejecting pin 43 of the ejecting mechanism 41 incorporated in the fixed die 21 has been described, but the present invention is of course applicable to the ejecting mechanism incorporated in the movable die. It can also be applied to protruding pins.

[0025]

According to the first aspect of the present invention, in the die device with an ejection mechanism in which the gas vent is formed by the gap between the ejection pin and the peripheral surface of the through hole, the ejection pin is
With a tip fitting portion of substantially the same cross-sectional shape as the through hole to the cavity side has a concave groove on a peripheral surface adjacent to the tip fitting portion, the recessed groove, the portion leading to at least the tip fitting portion < Since the first taper portion having a smaller cross-sectional shape in the direction away from the cavity is included , even if the cavity forming surface of the mold body contacts the portion of the recessed groove of the ejector pin that is connected to the tip fitting portion. In addition, the ejection pin does not malfunction, and the cavity forming surface is not damaged or worn. Therefore, molding defects such as burrs in the product can be prevented.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the angle formed by the first tapered portion with respect to the axial direction of the protrusion pin is set to 0 ° 30 'to 30 °. While ensuring the size of the gas vent, it is possible to reliably prevent malfunction of the ejection pin, damage to the cavity forming surface, and abrasion.

According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, the through hole has a narrowed portion having a smaller cross-sectional area than the other portions at the end portion on the cavity side. , the groove becomes smaller second tapered portion there of the cross-sectional shape toward the cavity side opposite the portion and the tip fitting portion
That since, in the step portion of the narrowed portion in the through hole of the formed body, even hit the opposite side portion and the tip fitting portion in the groove, does not cause malfunction of ejector pins.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view near an ejection pin showing an embodiment of a die device with an ejection mechanism of the present invention.

FIG. 2 is a sectional view of the whole of the same.

FIG. 3 is a side view showing a method for manufacturing the same protruding pin.

FIG. 4 is a cross-sectional view showing the vicinity of an ejection pin showing an example of a conventional die device with an ejection mechanism.

[Explanation of symbols] 21 Fixed type (mold body) 22 Movable type (mold body) 23 Cavity 41 Fixed side ejection mechanism (ejection mechanism) 43 Ejection pin 47 Through hole 48 Small diameter portion (narrowed portion) 51 Tip fitting portion 52 Groove 53 First tapered portion 54 Second tapered portion α Angle

Claims (3)

[Claims] 1. A plurality of mold bodies that open and close each other to form a cavity between them when the mold is closed, and a protrusion mechanism that is incorporated in the mold body and that ejects the molding material in the cavity when the mold is opened. In a die device with an ejection mechanism having an ejection pin penetrating a through hole formed in a mold body and forming a gas vent for releasing gas from the cavity by a gap between the ejection pin and the peripheral surface of the through hole. The ejecting pin has a tip fitting portion having substantially the same cross-sectional shape as the through hole on the cavity side, and has a groove for gas vent on a peripheral surface adjacent to the tip fitting portion,
The recessed groove is a die unit with an ejecting mechanism, characterized in that a portion connected to the tip fitting portion is a taper portion whose diameter decreases in a direction away from the cavity. 2. The die device with an ejection mechanism according to claim 1, wherein an angle formed by the tapered portion with respect to the axial direction of the ejection pin is 0 ° 30 'to 30 °. 3. The through hole has a constriction portion having a smaller cross-sectional area than other portions at an end portion on the cavity side, and the groove has
2. A taper part having a diameter smaller toward the cavity side on the side opposite to the tip fitting part.
Alternatively, the die device with an ejection mechanism according to the item 2.