JPH0688122B2 - Injection molding equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an injection molding device for injecting a melt into a mold cavity.

[Conventional technology]

For example, casting of aluminum-made disc foils for automobiles is often carried out by a vertical die casting machine due to a small amount of gas entrainment during melt injection.

FIG. 2 is a vertical cross-sectional view of the vicinity of the center of the die of a vertical die casting machine of this type disclosed in, for example, Japanese Patent Laid-Open No. 63-140747, which will be described with reference to FIG. Sleeve hole 1a of lower mold 1 which is a fixed mold fixed to the side
A fixed sleeve 2 formed in a cylindrical shape is fitted into the fixed sleeve 2. A cylindrical injection sleeve 3 supported on the injection cylinder side (not shown) is insertably / removably fitted into an inner hole of the fixed sleeve 2. Has been done. Further, a plunger tip 4a, which is the head of the plunger 4 connected to the piston rod of the injection cylinder, is fitted in the inner hole of the injection sleeve 3 so as to be movable back and forth.

Above the lower mold 1, an upper mold 5 as a movable mold formed in a convex shape with its central portion facing downward is aligned with the lower mold 1 and opened. It is supported so that it can move up and down. A plurality of cores 6 divided in the circumferential direction are formed between the outer peripheral portions of the upper mold 5 and the lower mold 1 so as to be movable back and forth in the radial direction. 7 is a cavity as a space formed between the upper and lower molds 5 and 1 and the core 6 which are closed, and is a central hub portion 7a formed in a recessed thick portion. A disk-corresponding portion 7b formed outside the hub-corresponding portion 7a in the shape of a horizontal disk, and a cylindrical shape provided almost vertically around the outer periphery of the disk-corresponding portion 7b. The runner 8 is integrally formed with the rim-corresponding portion 7c, and the lower half is tapered between the hub-corresponding portion 7a and the inner hole of the fixed sleeve 2.
Is communicated with. In the large-diameter portion 5a of the inner hole of the upper die 5, an extruding plate 10 supported by an elevating plate on the extruding cylinder side (not shown) via support pins 9 is slidably fitted in the vertical direction, Plural extruding pins are installed on the lifting plate and the extruding plate 10.
11, 12 are supported at their base ends with their tips facing the hub-corresponding portion 7a or the disc-corresponding portion 7b and the rim-corresponding portion 7c, respectively.

A pin 13 having a base end supported by a pin protruding cylinder side (not shown) is slidably inserted into a pin hole 5b formed in the center of the upper mold 5. The pin 13 is Cavity 7
At the normal time before the inside of the molten metal 14 is completely filled, the tip end surface is located at the same position as the inner surface of the cavity 7, and when the molten metal 14 is pressed near the completion of the filling operation, it is projected into the cavity 7 and its lower end. The portion is provided so that it can be inserted into and removed from the upper half small diameter portion of the runner 8. The pin 13 is formed so that the diameter of the insertion portion into the runner 8 is slightly smaller than the diameter of the small diameter portion of the runner 8. Further, the center of the pin 13 has a cooling water passage 13a extending near the tip thereof. Is provided.

With such a configuration, when the injection sleeve 3 in which the molten metal 14 is injected is joined to the fixed sleeve 2 and the plunger 4 is advanced, the molten metal 14 will be absorbed by the plunger tip 4a.
It is pushed by and is injected into the cavity 7 to be filled. Immediately before or immediately after the end of injection, when the pin 13 is lowered and the lower end of the pin 13 is thrust into the molten metal 14 in the runner 8 while the pushing force is continuously applied to the plunger tip 4a, the molten metal 14 is
The molten metal 14 is eliminated by and flows into the cavity 7, so that the molten metal 14 spreads to every corner of the cavity 7 by acting as a feeder. After the molten metal 14 in the cavity 7 is solidified and becomes a product, the pin 13 is retracted and the upper mold 5 is raised, and the product reaches the upper mold 5 and rises. Since a thin cylindrical solidified material is formed and remains on the inner peripheral surface of the small-diameter portion 8, the solidified material called a biscuit remaining in the fixed sleeve 2 is cut from this thin cylindrical portion. After the mold is opened, the core 6 is opened and the lifting plate is lowered.
1, 12 descend and the product is extruded from the cavity 7.

With such a configuration, the hub surface at the center of the disk portion, which is the decorative surface of the product, can easily remove the solidified matter and does not spoil the appearance even after the removal. Also, pin 13
The quality of the product is improved by the action of the feeder.

[Problems to be Solved by the Invention]

However, in such a conventional device, the tip surface of the low temperature pin 13 cooled by the cooling water in the cooling water passage 13a constitutes a part of the inner surface of the cavity 7, and the hub portion of the cavity 7 is formed. The molten metal 14 facing the corresponding portion 7a flows toward the disk portion corresponding portion 7b and the rim portion corresponding portion 7c while being filled with the injected molten metal 14 while colliding with the low temperature tip surface, so that the molten metal 14 is cooled. Begins to solidify, cavity 7
There is a problem that the quality of the product deteriorates due to the poor bathing inside.

It should be noted that such a problem does not occur only during the manufacturing of the disc foil by the vertical injection molding apparatus described above, and if it is a work for raising the metal, an injection molding apparatus other than the vertical type, for example, a horizontal mold clamping lateral This also occurs when a molded product other than a disc foil is manufactured by a general casting type die casting machine or the like, and therefore, in the present invention, these are also included in the problems to be solved.

[Means for Solving the Problems]

In order to solve such a problem, according to the present invention, a feeder pin is provided so that it can be inserted into and taken out from one surface of a mold cavity, and a cooling water passage communicating with the tip axial center portion inside the pin is provided. And a pin having a low thermal conductivity was provided at the tip of this pin formed of a material having a high thermal conductivity.

[Action]

When the molten metal is injected into the cavity, the molten metal flows while colliding with the tip surface of the pin, but because the collision portion has a portion with low thermal conductivity, heat exchange between the molten metal and the cooling water in the pin The amount is small and the molten metal is hardly cooled. When the pin is lowered and inserted into the melt passage before and after the molten metal is filled in the cavity, the molten metal in this passage is removed into the cavity, and a feeder action is performed.

〔Example〕

FIG. 1 is a vertical cross-sectional view of the vicinity of the center of a die of a vertical die casting machine as an embodiment of an injection molding device according to the present invention. In the figure, members having the same construction as the conventional device shown in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.
This will be briefly described below. Lower mold 1 to which injection sleeve 3 is joined, upper mold 5 above it, and both molds 1,
Between the core 6 between the five, a hub-corresponding portion 7a composed of a thick portion, a disc-corresponding portion 7b, and a rim-corresponding portion 7c.
A cavity 7 composed of and is formed. Between the hub-corresponding portion 7a and the insertion hole of the injection sleeve 3, the diameter is considerably smaller than the inner holes of the fixed sleeve 2 and the injection sleeve 3, and a small diameter cylindrical shape is formed. A runner 8 as a melt passage, which is composed of an upper half small diameter portion 8a formed and a tapered lower half portion 8b, is formed so as to communicate vertically.

Reference numeral 23 is a pin (not shown) which has a base end supported on the upper pin protruding cylinder side and which can move back and forth in the vertical direction, and is slidably mounted in a pin hole 5b provided in the center of the upper mold 5. In the normal state before filling the molten metal 14 into the cavity 7, the pin 23 is located at a position where the tip end surface is aligned with the inner surface of the cavity 7, and is close to the completion of filling the molten metal 14 At the time of operation, it is provided so as to project into the cavity 7 and the lower end portion thereof can be inserted into and removed from the upper half small diameter portion 8a of the runner 8. The outer diameter of this pin 23 is the small diameter part of the runner 8.
It is formed slightly smaller than the inner diameter of 8a, for example, when the diameter of the small diameter portion 8a is 40 to 60 mm, the outer diameter of the pin 23 is
It is smaller than this, for example, by 1 to 5 mm. In addition, the pin 23 is provided with a cooling water passage 23a extending its axial center portion to a position near the tip thereof, with its rear end side being connected to a cooling source (not shown) so as to cool the pin 23 and its surroundings. Has been done.

The entire pin 23 except the tip is made of a material having a high thermal conductivity, for example, an iron-based material, a chromium molybdenum steel with a nitride layer formed on the surface thereof, or beryllium-copper. At this time, the tip portion 23b facing the upper end of the cavity 7 is formed of a material having a relatively low thermal conductivity. As a material having a low thermal conductivity, for example, a ceramic made of silicon nitride or silicon carbide or a ceramic made of Si, Ti, C, O and a small amount of B, N is used as a material such as Tyranno Coat (of the applicant company). (Registered trademark) or the like is used, and this is plated or sprayed on the tip end surface and the tip outer peripheral surface of the pin 23.

The operation of the vertical die casting machine configured as above will be described. The injection sleeve 3 in which the molten metal 14 is injected is joined to the fixed sleeve 2, and the plunger 4 is attached by the injection cylinder.
When is moved forward, the molten metal 14 is pushed by the plunger tip 4a, injected into the cavity 7 and filled. Immediately before or immediately after the end of injection, when the pin 23 is lowered by the pin projecting cylinder and the lower end portion thereof is thrust into the molten metal 14 in the cavity 7 and the runner 8, the molten metal 14 in this thrust portion is pinned.
Since it is removed at 23 and flows in the cavity 7, it acts as a feeder to spread the molten metal 14 to every corner of the cavity 7. After the molten metal 14 in the cavity 7 is solidified into a product and then the upper die 5 is raised, the product reaches the upper die 5 and rises. At this time, the pin 23 and the small diameter portion of the runner 8 Since a thin cylindrical solidified material is formed between the runner 8 and
A solidified material called a biscuit is cut from this thin-walled cylindrical portion. After opening the mold, when the core 6 is opened and the elevating plate is lowered, the push pins 11 and 12 are lowered and the product is moved into the cavity 7.
Is extruded from. Coolant passage for pin 23 during injection of molten metal 14
Cold water circulates in 23a, and the pin 23 is cooled.

In such an injection operation, when the molten metal 14 is injected and distributed, as shown in the drawing, the tip end portion 23b which is the lower end surface portion of the pin 23 is
Has a low thermal conductivity facing one inner surface of the cavity 7, and the molten metal 14 ejected from the runner 8 has a tip portion of the pin 23.
After colliding with 23b, it splits into the right and left and heads for the rim-corresponding portion 7c. However, in this device, since the tip portion 23b of the pin 23 is formed of a material having a relatively low thermal conductivity, it enters the cavity 7. There is almost no heat exchange between the injected molten metal 14 and the cooling water in the cooling water passage 23a, and the molten metal 14 does not cool.Therefore, the molten metal 14 does not begin to solidify, and the molten metal flow state is maintained well. The molten metal 14 is well spread to every corner of the cavity 7 to obtain a molded product of good quality. Also pin
After pouring the molten metal 23 into the molten metal 14,
However, since it corresponds to a portion having a high thermal conductivity, the molten metal 14 easily cools even in a thick portion, and solidification is promoted. And
Finally, even in the part where the molten metal 14 fills the cavity 7 and the wall thickness is large and solidification and solidification tend to be delayed, the cooling action cools the part, so that the solidification of this part becomes faster and the mold becomes faster accordingly. The opening time can be shortened, the cycle time can be shortened, and the productivity can be improved.

In addition, in the above-mentioned embodiment, a case of manufacturing a disc foil for an automobile using a vertical injection molding apparatus will be described.
The case where the pin 23 is projected into the hub-corresponding portion 7a and the runner 8 has been described, but this is also used in the case where a molded product other than the disc foil is manufactured as long as it causes a feeder action. Further, it can also be used in other types of injection molding apparatuses such as a horizontal die-clamping horizontal injection type general die casting machine and an injection molding machine. Of course, it is desirable that the feeder action by the pin is performed at a portion that does not hinder the shape of the molded product.

In the above embodiment, the cooling water passage 23a is connected to the pin 23
I have shown an example that it is provided over the entire length of Nono.
It may be provided only half of the total length of 23 or only near the tip portion 23b. In this case, for convenience of processing, the pin 23 should be connected to the cooling water passage 23a.
It is necessary to add more at the boundary between the part with and without.
By doing so, not only the same effects as those of the above-described embodiment are obtained, but also the hole processing is reduced as compared with the above-mentioned embodiment, so that the processing is easy and the pin strength is increased.

〔The invention's effect〕

As is clear from the above description, according to the present invention, in the vertical injection device, the feeder pin is provided so as to be freely inserted into and removed from one surface of the die cavity, and the tip axial center portion is provided inside the pin. By providing a cooling water passage leading up to, the tip of this pin made of a material with high thermal conductivity has a portion with low thermal conductivity, so that the molten metal is Since the tips of the pins that come into contact with each other do not conduct the low temperature of the cooling water to the molten metal and the molten metal does not cool, the molten metal flows well and spreads well to every corner of the cavity, improving the quality of the molded product. In addition, when the pin protrudes, the molten metal in the cavity or the like is removed by the pin and pushed toward the other parts in the cavity, which promotes the function of the molten metal. The quality of the molded product is further improved because it is pushed out and the molded product is dense and does not contain gas. In addition, after the molten metal is filled, the molten metal in the thick portion around the portion with high thermal conductivity on the outer peripheral surface of the pin is rapidly cooled and solidified by the action of the cooling water in the pin. The cooling and solidification of the whole becomes quicker, the mold opening can be made faster correspondingly, the cycle time can be shortened, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an injection molding apparatus according to the present invention, and FIG. 2 is a vertical sectional view of a conventional apparatus similar to the present invention. 1 ... Lower mold, 2 ... Fixed sleeve, 3 ... Injection sleeve, 5 ... Upper mold, 6 ... Core, 7 ... Cavity, 8
...... runner, 14 ...... molten metal, 23 ...... pin, 23a …… cooling water passage, 23b …… tip part.

Claims (1)

[Claims] 1. A feeder for raising a metal is provided to be freely inserted into and removed from one surface of a mold cavity, and a cooling water passage communicating with a tip axial center portion is provided inside the pin, so that a high thermal conductivity is provided. An injection molding apparatus characterized in that a tip having a low thermal conductivity is provided at a tip portion of the pin formed of a material.