JP2004042295A - Ejector pin for mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To add a degassing function and ensure an efficient degassing process and control the generation of deposits, in an ejector pin for a mold. <P>SOLUTION: In the ejector pin 11 for a mold which is formed so as to enable its free insertion into an insertion hole 13 drilled in the mold 12 and works for injecting a molding material 14 into the mold 12, the main body 15 of the ejector pin 11 is made to coincide with the axial center at the tip of the ejector pin 11 and a reduced diametral part 16 of a specified length is formed. When the main body 15 of the ejector pin 11 is loosely inserted into the insertion hole 13 in a freely sliding manner, an annular gap formed between the reduced diametral part 16 and the insertion hole 13 serves as a degassing passage(b). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projecting pin for a mold, and more particularly, to a mold formed to be freely insertable into an insertion hole formed in an injection mold, and for injecting a molding material into the mold. TECHNICAL FIELD The present invention relates to a projecting pin for a mold, which is provided with a degassing function to the projecting pin for a mold and has an improved gas venting effect in the mold.
[0002]
Problems to be solved by the prior art and the invention
In a conventional injection molding mold of this type, an insertion hole is formed at a predetermined position of the mold, and a molding material is injected by inserting a protruding pin for the mold into the insertion hole. Since gas is generated after injection, the quality of the molded product is maintained by degassing the gas.
[0003]
In particular, in thin-wall molding or precision molding, sufficient degassing is required, and if degassing is performed incompletely, quality cannot be maintained, which may lead to a large number of defective products.
[0004]
Therefore, in a conventional injection molding die, a plurality of degassing core pins are incorporated in a die, and degassing is performed by the degassing core pins.
However, when the molding material adheres to the degassing core pin and the degassing effect is lost, it is difficult to remove the adhering matter by disassembling the mold or the like.
[0005]
In order to reduce the number of core pins used for degassing, there has been known a die provided with a degassing function for projecting pins for injection of a molding material. The mold projecting pin having the gas release function will be described with reference to FIG. In the drawing, reference numeral 1 denotes a mold protruding pin, which is formed so as to be inserted into an insertion hole 3 formed in a mold 2 and to inject a molding material 4. I have. When the projecting pin 1 for a mold is inserted into the insertion hole 3, the projection pin 1 has a gap a between itself and the insertion hole 3, and the gap a is an escape passage for gas generated in the molding material 4. It has become. Accordingly, the gas can be released by the mold projecting pin 1 and the mold projecting pin 1 can be freely inserted into and removed from the insertion hole 3, so that when an attached matter is generated, the attached matter can be easily removed. is there.
[0006]
However, when the mold projecting pin 1 is inserted into the insertion hole 3, it is not held so that the axis of the mold projecting pin 1 coincides with the axis of the insertion hole 3. The projecting pin 1 for a mold may be eccentric in the insertion hole 3. In particular, when the molding material 4 is injected with the projecting pin 1 for a mold, the projecting pin 1 tends to be eccentric. There is a problem that the molding material 4 enters the gap a between the insertion hole 3 generated by the eccentricity and generates a large amount of deposits. When a large amount of deposits are generated, there is a possibility that the quality of the molded product is deteriorated.
[0007]
Further, there is a problem that the gas generated in the molding material 4 due to the eccentricity of the mold projecting pin 1 is not uniformly and smoothly discharged.
Therefore, in the projecting pin for the mold, a degassing function is added, enabling good degassing, and a technical problem to be solved in order to suppress generation of deposits arises. An object of the present invention is to solve this problem.
[0008]
[Means for Solving the Problems]
The present invention has been proposed to achieve the above object, and is formed to be freely insertable into an insertion hole formed in a mold, and is provided with a mold protrusion for injecting a molding material into the mold. In the pin, at the tip of the mold projecting pin, the mold projecting pin main body is aligned with the axis, and a reduced diameter portion having a reduced diameter is formed, and the mold projecting pin is formed. When the pin body is slidably inserted into the insertion hole, a mold is configured such that an annular gap formed between the reduced diameter portion and the insertion hole becomes a gas escape passage. Projecting pin,
And a small-diameter portion having a predetermined length smaller than the reduced-diameter portion is formed in the adjacent portion of the reduced-diameter portion of the die projecting pin main body, and an annular ring formed between the small-diameter portion and the insertion hole. A projecting pin for a mold, the gap being configured as a gas reservoir,
And a mold projecting pin, wherein the mold projecting pin main body is partially cut away to form a cutout portion, and the cutout portion is configured as a gas escape passage.
In addition, the notch provides a die protruding pin in which a D-cut portion is formed by notching an outer portion of the die protruding pin body in a plane in the axial direction.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. In the figure, reference numeral 11 denotes a projecting pin for a mold, which is formed so as to be inserted into an insertion hole 13 formed in a mold 12 to inject a molding material 14. . Then, a reduced-diameter portion 16 having a predetermined length whose axis is aligned with the die-projecting pin main body 15 and whose diameter is reduced is formed at the tip end of the die-projecting pin 11. When the pin body 15 is slidably inserted into the insertion hole 13, an annular gap formed between the reduced diameter portion 16 and the insertion hole 13 becomes a gas release passage b. Have been.
[0010]
Further, a small-diameter portion 17 having a predetermined length smaller than the reduced-diameter portion 16 is formed in a portion adjacent to the reduced-diameter portion 16 of the die projecting pin main body 15, and the small-diameter portion 17 and the insertion hole 13 are formed. The annular gap formed therebetween is configured to be a gas reservoir c.
[0011]
The die projecting pin main body 15 is partially cut out in an axially planar shape at an outer portion of the die projecting pin main body 15, so-called D-cut portions 18, 18, 18 are formed at three places. And gas escape passages d, d, and d are formed between them. The formation of the D-cut portions 18, 18, 18 is not limited to three places, but may be one place, for example, and can be formed at any place. Further, instead of the D-cut portion 18 formed on the projecting pin main body 15 for the mold, it is also possible to form it into another shape.
[0012]
Therefore, when the mold projecting pin 11 is inserted into the insertion hole 13 and the molding material 14 is injected by the mold projecting pin 11, the gas generated in the molding material 14 is reduced by the reduced diameter portion 16 and the insertion hole. 13, the gas escape passage b formed in the gap between the small-diameter portion 16 and the gas reservoir c formed between the gap between the insertion hole 13, and the gas escape passage b formed in the mold projecting pin body 15. The gas is scattered to the outside through gas escape passages d, d, d formed by the cut portions 18, 18, 18 and the insertion holes 13.
[0013]
At this time, since the axis of the reduced-diameter portion 16 coincides with the axis of the projection pin body 15 for the mold, as described above, the projection pin 11 for the mold Since the diameter-reduced portion 16 is centered in the insertion hole 13 in a state where the hole 15 is loosely inserted into the insertion hole 13, the gas escape passage b formed on the outer periphery of the diameter-reduced portion 16 has a uniform thickness. The gas generated from the molding material 14 is uniformly and smoothly discharged from the gas release passage b, and the deposit formed by protruding toward the gas release passage b is a conventional example. Becomes extremely small as compared with
[0014]
In this way, since the reduced-diameter portion 16 of the mold projecting pin 11 is centered by the mold projecting pin main body 15 as described above, gas can be uniformly and smoothly vented. The generation of deposits in the gas escape passage b formed by the reduced diameter portion 16 can be suppressed, and the gas escape c of the gas escape passage b can be released by the gas reservoir c formed by the small diameter portion 17. It is performed smoothly. Further, there is an advantage that the gas is smoothly vented by the D-cut portion 18 of the projecting pin main body portion 15 for the mold, and the D-cut portion 18 is easily processed.
[0015]
The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.
[0016]
【The invention's effect】
As described in detail in the above embodiment, the present invention according to claim 1 is a mold protruding pin, wherein the die protruding pin main body and the shaft center are provided at the tip of the mold protruding pin. And a reduced diameter portion having a predetermined length reduced in diameter is formed, so that when the mold projecting pin body is slidably inserted into the insertion hole, the reduced diameter portion and Since an annular gap formed between the insertion hole and the insertion hole serves as a gas escape passage, the reduced diameter portion is centered in the insertion hole, and the gas escape passage is formed in an annular gap having a uniform thickness. In addition, the gas can be smoothly discharged, and the generation of deposits can be suppressed.
[0017]
The invention according to claim 2 is characterized in that a small-diameter portion having a predetermined length smaller than the reduced-diameter portion is formed at a portion adjacent to the reduced-diameter portion of the projecting pin body for a mold, and the small-diameter portion and the insertion hole are formed. Since the annular gap formed between the reduced diameter portion and the insertion hole is configured so as to serve as a gas reservoir, a gas escape formed between the reduced diameter portion and the insertion hole is provided. It is possible to satisfactorily vent the passage.
[0018]
Furthermore, in the invention according to claim 3, the projecting pin main body for the mold is partially notched to form a cutout portion, and the cutout portion is configured to be a gas release passage. In addition to the effects of the invention described in 2, the gas in the gas reservoir can be easily discharged by the notch.
[0019]
Further, in the invention according to claim 4, since the notch portion is formed with a D-cut portion formed by cutting out the outer portion of the projecting pin body for the mold in a plane in the axial direction, the effect of the invention according to claim 3 is provided. In addition to the above, the D-cut portion is an invention having a very great effect such as easy processing.
[Brief description of the drawings]
FIG. 1A is a front vertical sectional view showing an embodiment of the present invention and showing a state in which a mold projecting pin is inserted into a mold.
(B) Sectional view along the line AA in FIG. 1 (a).
FIG. 2 (a) is a front longitudinal sectional view showing a conventional example, in which a mold protruding pin is inserted into a mold.
2B is a sectional view taken along line BB of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Protrusion pin for mold 12 Mold 13 Insertion hole 14 Molding material 15 Protrusion pin body 16 for mold 16 Reduced diameter portion 17 Small diameter portion 18 D cut portions a, b, d Gas escape passage c Gas reservoir

Claims (4)

A mold protruding pin formed so as to be insertable into an insertion hole formed in a mold and for injecting a molding material into the mold, wherein a mold is provided at a tip end of the mold protruding pin. When the projecting pin main body is aligned with the shaft center thereof and has a reduced diameter portion of a predetermined length reduced in diameter, and the mold projecting pin main body is slidably and freely inserted into the insertion hole. And a projecting pin for a mold, wherein an annular gap formed between the reduced diameter portion and the insertion hole serves as a gas escape passage. A small-diameter portion having a predetermined length smaller than the reduced-diameter portion is formed at the adjacent portion of the reduced-diameter portion of the mold protruding pin main body, and an annular gap formed between the small-diameter portion and the insertion hole is formed. 2. The projecting pin for a mold according to claim 1, wherein the projecting pin is configured to be a gas reservoir. 3. The mold protrusion according to claim 1, wherein the mold protrusion pin main body is partially notched to form a cutout portion, and the cutout portion serves as a gas escape passage. pin. 4. The projecting pin for a mold according to claim 3, wherein the notch is formed by forming a D-cut portion in which an outer portion of the projecting pin main body for the mold is cut out in an axial plane.

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