JPH09262871A - Sprue part structure of mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sprue part structure smoothly guiding the molten matter injected into a mold to a liner and capable of molding a product of good quality. SOLUTION: A sprue formed into an almost truncated cone-shaped space is provided to the part connected to the nozzle 40 of an injection molding machine of a mold 10 and the taper part thereof becomes a gate 13 opened to the outside and the bottom surface opposite thereto of the sprue is closed by a deep wall. A recessed part 14 is provided to the deep wall so as to be opposed to the gate 13 so as to be capable of housing the plug P jetted along with molten matter. The opening of the liner 15 on the side of the deep wall 13 is provided to the upper inner wall of the sprue and the protruding member protruding from the deep wall is superposed on the lower inner wail of the sprue not only to form the guide surfaces 23 upwardly inclined to both sides of the opening of the recessed part 14 from the lower inner wall but also to allow the opening of the linear 15 to continue to the lower inner wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sprue portion structure of an injection molding die.

[0002]

2. Description of the Related Art Conventionally, a sprue portion structure provided in an injection molding die has a truncated cone shape regardless of whether it is a metal molding die or a resin molding die. The liner is branched at a right angle on the side. The details of the structure will be described below with reference to FIGS. 9 to 12, for example, a mold for injection molding of a magnesium alloy. As shown in FIG. 9, the injection molding die 1 includes a liner 2 and a product cavity (not shown) along a parting line L which is a mating surface of the fixed side die 1a and the movable side die 1b. ) Etc. The sprue 3 is formed so as to penetrate the movable mold 1b and is continuous with the liner 2. When the hot water of the injection molding machine 5 is poured into the outer opening of the sprue 3, the hot water flows into the liner 2 and the cavity. It has become.

The sprue 3 is formed so as to be orthogonal to the parting line L because of, for example, the positional relationship between the mold 1 and the injection molding machine. In order to apply the above, the conventional one has a truncated cone shape. In addition, the injection molding machine 5 shown in this example
Is for blocking the hot water by solidifying the hot water at the tip of the nozzle 5a, and a recess 4 is provided on the back wall of the sprue 3 to receive the solidified product of the hot water (hereinafter referred to as "plug P"). . The hot water poured into the mold 1 goes straight through the sprue 3, reaches the inner wall, and then enters the liner 2. The sprue part of the molded product formed by the mold 1 is as shown in FIG. In the figure, "C" is attached to the reference numeral of the part corresponding to the above-mentioned parts.

[0004]

Since the conventional sprue including the above-mentioned magnesium alloy sprue 3 has a truncated cone shape, the side wall and the back wall intersect at an acute angle, and as shown by the arrow in FIG. Especially in the lower side, the flow direction of the hot water changes rapidly. Therefore, the hot water bounces in the sprue, causing a turbulent flow, the flow resistance of the hot water increases, and the hot water does not flow smoothly to the liner, which adversely affects the quality of the product. In addition, particularly in the case of a magnesium alloy having a high melt viscosity, there is a property that the hot water flows along the inner wall, and the fact that the hot water does not flow smoothly in the liner 2 is added to the sprue as shown in FIG. There was a problem that gas g could not be left in 3 and gas could not be released from the mold.

The present invention has been made in view of the above problems, and smoothly guides the hot water poured into a mold to a liner,
It is an object of the present invention to provide a sprue part structure capable of molding a high quality product.

[0006]

In order to achieve the above object, the invention according to claim 1 has a structure of a mold runner, which is connected to a nozzle of an injection molding machine, and from this nozzle It has a spout for injecting hot water into the inside of the sprue, a sprue formed in a hollow shape inside the sprue, and a liner that branches off from the front side of the back wall of the sprue and drains the hot water from the sprue to the cavity side. The feature is that a guide surface that gently guides the hot water is formed from the side opposite to the liner to the inlet of the liner.

The invention according to claim 2 is the sprue part structure of the die according to claim 1, wherein the back wall of the sprue is recessed so as to receive a plug formed by solidifying hot water at the nozzle tip. The guide surfaces are formed in pairs on both sides of the recess, and the wall surface of the portion between the guide surfaces facing the recess is formed so as to be continuous with the opening of the recess. It has characteristics.

[0008]

In the invention according to claim 1 configured as described above, the hot water which has advanced along the wall surface on the side opposite to the liner in the sprue can be gently changed in its flow direction by the guide surface, It can flow on the wall toward the liner and smoothly flow into the liner. As a result, the hot water is well distributed to the product cavities and the like, and high quality products can be molded.

Further, in the invention according to claim 2 configured as described above, even in the case of a mold sprue for an injection molding machine in which hot water is solidified to form a plug, the function of the recess for receiving the plug is impaired. Instead, the hot water in the sprue can be poured smoothly into the liner to improve the distribution of the hot water, and high quality products can be molded.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A sprue structure according to the present invention will be described below, for example, in a die 1 for a magnesium alloy injection molding machine.
The embodiment applied to No. 0 will be described based on FIGS. 1 to 8. FIG. 1 shows a mold 10 and a nozzle 4 of an injection molding machine.
It shows the part to be combined with 0. The mold 10 includes a fixed side mold 20 and a movable side mold 30 which form a pair, and a cavity (not shown) and a runner 11 for molding a predetermined casting product inside by combining the two molds. And are to be molded.

The runner 11 is mainly formed along a parting line L which is a joint surface between the fixed side mold 20 and the movable side mold 30, and at the joint portion with the nozzle 40, the movable side. A hollow sprue 12 is provided so as to penetrate the die 30 in the thickness direction. The nozzle 40 is connected to the outer opening 13 of the sprue 12 (hereinafter referred to as "gate 13") so that molten magnesium alloy water can be injected into the runner 11.
The sprue 12 moves from the parting line L to the sprue 1 in the movable die 30 in consideration of the draft of a so-called casting.
It is formed in a space of a substantially truncated cone shape that is tapered toward 3, and the bottom surface portion thereof is closed by the fixed-side mold 20. On the wall surface of the fixed-side mold 20 that closes the bottom surface (hereinafter referred to as "back wall 21"), a recess 14 having an opening having substantially the same diameter as the gate 13 is formed so as to face the gate 13. The plug P formed by solidifying the molten metal at the tip of the nozzle 40 is accommodated when pouring the molten metal so that the plug P does not flow into the cavity downstream of the runner. still,
This concave portion 14 is also drafted to make a parting line L.
The inner wall 21 side is tapered.

On the peripheral wall of the sprue 12, an end of a liner 15 which is adjacent to the parting line L and is connected to the cavity is opened at the upper side.
The liner 15 forms a path by closing the groove formed in the movable mold 30 along the parting line L with the inner wall 21 and bends in a crank shape at a position away from the sprue 12 to be connected to the cavity. ing. Sprue 12
In the lower side of the peripheral wall of the
An arcuate wall 22 protruding from the sprue 12 extends up to about the middle of the sprue 12. As shown in FIG. 4, the arc-shaped surrounding wall 22 is erected on the peripheral edge of the lower half of the opening of the recess 14 and tapers toward the tip so that the lowermost end of the opening of the recess 14 projects most. And this arc-shaped enclosure 2
The outer peripheral surface of 2 is formed so as to be in close contact with the inner wall for forming the sprue which is in the shape of a truncated cone of the movable die 30, and the inner peripheral surface is connected to the opening of the recess 14.

A guide surface 23, which is similar to the cut surface shape when the cylinder is cut diagonally, is formed at the peripheral edge of the arc-shaped surrounding wall 22. Therefore, when the arc-shaped surrounding wall 22 is viewed from the lateral direction, as shown in FIG. 1, the guide surface 23 inclines upward from the tip to the base portion, and the guide surface 23
Have a smooth curved surface 23a on the base side thereof and are continuous in pairs on both sides of the opening of the recess 14. The sprue 12 at one end of the sprue 12 is tapered when viewed from the sprue 12 side, and a hemispherical recess 16 is formed from the tapered portion to the outer wall surface of the movable mold 30. The nozzle 40 of the injection molding machine can be received in the recess 16.

The nozzle 40 of the injection molding machine has its nozzle 4
The jet port 42 of 0 tip is faced to the sprue 13 and can be brought into contact with or separated from the movable side mold 30. Further, a hemispherical surface 41 is provided at the tip of the nozzle 40, and the ejection port 42 is opened at the tip thereof. The curvature of the hemispherical surface 41 and the diameter of the ejection port 42 are the same as those of the mold 10 described above.
2 is smaller than the curvature of the recess 16 and the diameter of the sprue 13. When the tip of the nozzle 40 is brought into contact with the movable mold 30, the spout 42 is moved from the sprue 12 to the inside of the sprue 12 as shown in FIG. Protruding slightly to the edge of the sprue 13 and the hemispherical surface 4
1 are in close contact with each other so that the hot water can be poured into the runner 11 without leakage. Further, the nozzle 40 forms the plug P at the tip by cooling the hot water as described above. The plug P is used for shutting off the hot water, and the nozzle P inside the nozzle 40 is jetted. It can be released by increasing the pressure and spout hot water.

The sprue part of the molded product formed by the mold 10 is as shown in FIGS. In the figure, "C" is attached to the reference numeral of the part corresponding to the above-mentioned parts. The situation inside the sprue 12 when pouring hot water into the mold 10 configured as described above will be described. The jet port 42 of the nozzle 40, in which the jet of hot water is blocked by the plug P, is made into the recess 1 of the movable mold 30.
6 Combine with the sprue 13 inside. Then, when an internal pressure is applied to the inside of the pipe of the nozzle 40 by the injection molding machine, as shown in FIG. 2, the plug P that has blocked the hot water at the tip of the nozzle 40 is removed and the molten magnesium alloy water is melted in the sprue 12. Injected.

Hot water having a high viscosity such as a magnesium alloy has a property of flowing along the inner wall of the runner, so that it is filled in the sprue 12 as follows. That is, in the inner wall on the lower side of the sprue 12, the hot water travels along the inner wall of the movable mold 30 and rides on the guide surface 23 of the arc-shaped surrounding wall 22 on the way, and a part of the hot water directly follows the guide surface 23 and goes obliquely upward. Other than that, the vehicle goes over the guide surface 23 and goes inside the arc-shaped surrounding wall 22 toward the inner wall 21.
The hot water that travels along the guide surface 23 is curved on the back wall 21 side.
At a, the direction is gently changed and heads upward. Since the upper surface of the sprue 12 draws a curved surface in the upper part and an opening is waiting for the liner 15 at the center thereof, the hot water directed upward flows along the curved surface and smoothly flows into the liner 15.

The hot water which has passed over the guide surface 23 and has proceeded toward the inner wall 21 inside the arc-shaped enclosure wall 22 reaches the inner wall 21 while pushing the plug P, and the molten metal reaches the inner wall 21.
It is pushed into the concave portion 14 and is filled inside the arc-shaped surrounding wall 22. The filled hot water is guided to the above-mentioned guide surface 23 immediately beside and dragged by the hot water flowing upward,
Similarly, it flows upward into the liner 15.
On the other hand, the hot water on the upper side of the sprue 12 flows along the inner wall surface and reaches the inner wall 21. On the inner wall 21 side, the hot water that has moved downward is pushed upward by the guide surface 23, and is dragged by it and flows into the opening of the uppermost liner 15.

As described above, all the hot water that has gone straight through the sprue 12 gradually changes its flowing direction and goes upward, and smoothly flows into the liner 15 which serves as an escape route. Therefore, the gas existing in the sprue 12 also enters the liner 15 by riding on the flow of the hot water, and can be quickly discharged out of the mold 10 from a gas releasing portion (not shown) on the downstream side. Therefore, the gas in the sprue will not be mixed as fine bubbles in the hot water to form blow holes. Further, since the lower inner wall of the sprue 12 and the recess 14 of the inner wall 21 are continuous by the inner surface of the arc-shaped surrounding wall 22, the hot water advancing there is accompanied by the hot water advancing on the guide surface 23 along with the liner. The hot water does not become a turbulent flow in the back wall unlike the conventional sprue. Therefore, the fluidity is remarkably improved, the hot water is well distributed in the cavity, and a high quality product can be molded. <Other Embodiments> The present invention is not limited to the above-described embodiments. For example, embodiments described below are also included in the technical scope of the present invention. Various changes can be made without departing from the scope of the invention. (1) Although the mold 10 in the present embodiment is used for injection molding of magnesium alloy, it may be a mold used for injection molding of, for example, aluminum or iron other than magnesium alloy. Is not limited to metal and may be used for injection molding of resin.

However, as in the present embodiment, the higher the melt viscosity of the hot water, the more difficult it is for the hot water to flow in the mold, so that the effect of the present invention is further exerted. Further, the mold is not limited to the mold having the two-piece structure as in the present embodiment, and may be, for example, a three-piece structure mold or a special mold including a slide mold.
Further, the nozzle of the injection molding machine may be connected to either the movable side mold or the fixed side mold. (2) The sprue 12 in the present embodiment is provided with a recess 14 in the back wall 21 thereof so that the plug P can be accommodated therein. However, as long as it is a mold for an injection molding machine in which a nozzle is not formed with a plug. , It is not necessary to have a recess in the sprue.

However, in the sprue having the concave portion as in the present embodiment, the flow of the hot water becomes complicated and the quality of the product is easily affected, so that the effect of the guide surface according to the present invention is further exerted. (3) In this embodiment, the guide surface 23 is
It is formed by stacking an arcuate surrounding wall 22 protruding from the fixed side mold 20 in the space of the sprue 12 formed in the movable side mold 30. In addition, the guide surface 23 of the present embodiment is
Although it is formed in a flat slope shape when viewed from the side, it may be formed into a curved shape as a whole, for example. (4) In this embodiment, the liner 15 is the sprue 1
Although one is formed every two, a plurality may be formed. In this case, for example, the guide may be formed by forming a delta shape on the wall surface of the sprue and using the side surface as a guide surface to guide the hot water to the opening of each liner.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a coupling portion between a mold according to an embodiment of the present invention and a nozzle of an injection molding machine.

FIG. 2 is a cross-sectional view showing a state in which the mold and the nozzle are combined.

FIG. 3 is a cross-sectional view showing a state in which the mold is filled with hot water.

FIG. 4 is a perspective view showing an arcuate surrounding wall protruding from a stationary mold.

FIG. 5 is a perspective view showing a sprue portion of a molded product.

FIG. 6 is a view (side view) taken along the arrow VI in FIG.

FIG. 7 is a view (side view) viewed from the arrow VII in FIG.

8 is a view (bottom view) taken along the line VIII in FIG.

FIG. 9 is a cross-sectional view showing a connecting portion between a conventional mold and a nozzle of an injection molding machine.

FIG. 10 is a cross-sectional view showing a state where hot water flows in the mold.

FIG. 11 is a cross-sectional view showing a state where hot water is filled in the mold.

FIG. 12 is a perspective view showing a sprue portion of a conventional molded product.

[Explanation of symbols]

 10 ... Mold 11 ... Runway 12 ... Sprue 13 ... Gate 14 ... Recess 15 ... Liner 21 ... Back wall 22 ... Arc-shaped wall 23 ... Guide surface 40 ... Nozzle

Claims (2)

[Claims] 1. A structure of a runner of a die, which is connected to a nozzle of an injection molding machine and injects hot water into the die from the nozzle, and a cavity formed inside the gate. A sprue and a liner that branches off from the front side of the back wall of the sprue and flows hot water from the sprue to the cavity side, and the hot water flows from the inner wall surface of the sprue opposite to the liner to the inlet portion of the liner. A sprue part structure of a die, which is characterized in that a guide surface for gently guiding the is formed. 2. A recess is formed in the back wall of the sprue so as to receive a plug formed by solidifying hot water at the tip of the nozzle, and the guide surfaces form a pair on both sides of the recess. The sprue part structure of the die according to claim 1, wherein a wall surface of a portion which is formed between the guide surfaces and faces the recess is formed so as to be continuous with the opening of the recess.