JPH08174148A - Casting mold basin structure - Google Patents

Abstract

(57) [Summary] [Purpose] In the casting method in which the mold is opened when the shell-like solidified layer is formed on the surface, the mold opening timing is accelerated. [Structure] A sprue 10 formed by combining dies 6 and 7
In a mold casting process in which the molten metal is poured from the mold and the mold is opened when a shell-like solidified layer is formed on the surface layer of the molten metal filled in the runner 12, the product cavity 9, etc. A hot water pool 11 having a large passage area is formed.
1 is located below the sprue 10 and above the product cavity 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting mold suitable for a casting method in which a molten metal is poured into a cavity, a shell-like solidified layer is formed on the surface of the cavity, and the mold is opened when the inside is not solidified. Regarding the hot water pool structure.

[0002]

2. Description of the Related Art In order to improve the productivity in die casting, improve the accuracy of products, and extend the life of products, the surface layer of molten metal is rapidly solidified by using a die with high thermal conductivity, and the surface layer is a shell. A casting method is known in which the mold is opened when it is solidified.
In such a die casting method, for example, JP-A-5-6
As shown in Japanese Patent Publication No. 9083, the fixed type and the movable type have a high heat transfer property of the molten metal poured from the sprue in all parts from the design part such as the sprue and runner to the product cavity. A chill layer is formed on the surface layer by rapidly cooling by using, and the mold is opened when the inside is not solidified.

[0003]

By the way, generally, the temperature of the molten metal is highest near the spout which is the pouring port, and the mold cannot be opened unless the solidification near the spout progresses.
Therefore, for example, it is conceivable to reduce the volume of the sprue to accelerate the solidification rate and to open the mold early to increase the molding cycle. In this case, depending on the shape of the runner, the shape of the product cavity, etc. May overflow and may be a cause of casting burrs and the like.

[0004]

In order to solve the above problems, the present invention is directed to pouring a molten metal from a gate above a casting mold.
A hot pool having a large passage area was formed in the middle of the runway for feeding the poured molten metal into the product cavity, and the hot pool was arranged below the gate and above the product cavity.

Here, it is effective to provide a cooling water passage around the pool to forcibly cool the molten metal inside, and the cross section of the pool has a substantially circular shape so that the pool The taper part is provided at the connecting part between the part and the runner,
It has an abacus shape.

[0006]

[Function] A hot water pool with a large passage area is provided in the middle of the runway,
In the past, the molten metal that had been filled up to the sprue and solidified was used up to the pool. Since the contact area between the molten metal and the mold is expanded in this pool, the solidification rate is accelerated and the mold opening time can be accelerated. Further, since the inside of the molten metal is not solidified, if the molten metal pool is installed at a position lower than the product portion, the molten metal inside may overflow when the mold is opened. For this reason,
The basin is located below the sprue and above the product.

If a cooling water passage is provided around the basin for forced cooling, the solidification of the basin can be further accelerated, and the cross section of the basin can be formed into a substantially circular shape. By providing a taper portion having a draft angle at the joint between the pool portion and the runner, it is possible to prevent the occurrence of an undercut portion during mold opening.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a configuration diagram showing an entire casting system to which a casting mold having a basin structure according to the present invention is applied, and the casting mold having a basin structure according to the present invention is shown in FIG. It is applied to a fully automatic casting system for steering knuckles, which are the components of automobiles as shown in
This system uses a so-called QC (quick casting) process in which a shell-shaped solidified layer is formed on the surface of the molten metal by a copper mold with high thermal conductivity, and the mold is opened and discharged when the inside is not solidified. ing.

A casting device 1 is arranged substantially in the center of the above casting system. The casting device 1 is composed of a fixed mold 2 and a movable mold 3, and a fixed mold 2 is provided upstream of the casting device 1. A pouring station 40 for pouring the molten metal into the product cavity formed when the movable mold 3 and the movable mold 3 are closed is provided.

This pouring station 40 is equipped with a pressurizing pouring furnace 4
1, a load cell 42, and a ladle 43 that receives molten metal discharged from the pressure pouring furnace 41 and pours the molten metal into the casting apparatus 1, and the load cell 42 sets the amount of molten metal in the ladle 43 to a constant amount. After that, the ladle 43 is cast into the casting device 1
It is moved to the upper side and poured from the sprue through the runner into the product cavity.

Further, in the pressurized pouring furnace 41, the molten metal produced in the melting furnace 44 arranged further upstream is conveyed to the ladle 4
I will supply it at 5. Further, an additive measuring device 50 for adding an additive such as magnesium for spheroidizing graphite to the molten metal is provided above the casting device 1, and adjacent to the additive measuring device 50, a cavity is provided. A blow smoke device 51 for applying a release agent to the surface is provided so as to be vertically movable.

Further, above the downstream side of the casting apparatus 1, a work take-out robot 5 for taking out a cast product from the opened mold.
2 is provided so as to be movable in the horizontal direction, and the cast product taken out is transferred to the straightening / cutting device 53.

After the trimming and the like is performed by the straightening / cutting device 53, the transfer robot 54 transfers it to the heat treatment furnace 55. In the figure, reference numeral 56 is a filter exchanging device for exchanging a filter for removing slag or the like arranged in the runway, for example, for every shot.

Next, the structure of the casting apparatus 1 will be described with reference to FIGS. 2 to 4. Here, FIG. 2 is a vertical cross-sectional view of the cavity of the casting mold, FIG. 3 is a front view of the movable mold seen from the AA direction in FIG. 2, and FIG. 4 is a side view of the movable mold.

Fixed mold 2 and movable mold 3 which form the casting mold 1.
2, includes molds 6 and 7 clamped and held by respective mold mounting plates 4 and 5, and the mold mounting plates 4 and 5 are made of cast iron or steel. , 7 are made of copper alloy having good thermal conductivity.

As shown in FIG. 3, the mold matching surface of the movable mold 7 is provided with a plan portion 8 in the center and a pair of product cavities 9 and 9 on both sides.
Vertical runners 12, a large pool 11 provided in the middle of the vertical runners 12, horizontal runners 13 and 13 separated from the bottom of the vertical runners 12 to the left and right, and Runner 1
It is composed of communicating runners 14 and 14 which are connected to the end portions of 3 and 13.

Filters 15 and 15 for removing impurities from the molten metal are installed in the middle of the horizontal runners 13 and 13, and product cavities formed in conformity with the product shape of the steering knuckle are provided above the communicating runners 14 and 14. 9 and 9 are in communication. As shown in FIG. 2, a metal core 16 and a cast core 17 for forming a through hole in a part of the product shape face the interior of the product cavity 9. The metal core 16 is fixed to the movable mold mounting plate 5, and the core 1
The cylinder unit 18 allows the unit 7 to be retracted into and retracted from the product cavity 9. Incidentally, in FIG. 2, 20,
Reference numeral 21 is an extrusion pin.

In the molds 6 and 7, cooling water passages 22 ...
Are formed. The cooling water passage 22 on the movable die 3 side
, Are gathered on the side surface of the movable mold mounting plate 5 via the cooling hoses 23 connected to both side surfaces of the movable mold 7, as shown in FIG. 3 and FIG. The cooling water sent in is the cooling water passage 22 around the cavity 8.
After circulating the mold to cool the mold 7, the cooling hose 23 ...
Is discharged through.

By the way, as shown in FIG. 3, the hot water pool 11 is provided below the sprue 10 and above the upper end of the product cavity 9. Further, as shown in FIG. 5 which is a sectional view taken along line BB of FIG. 3, the sectional shape is a circle with a large diameter, and the connecting portion between the basin 11 and the runner 12 has the shape shown in FIG. Tapered portions t, t having a draft angle as shown are provided. That is, the upper and lower tapered portions t of the basin 11 both have a so-called agate shape that gradually narrows outward.

As shown in FIG. 5, the cooling water passages 22 are provided around the pool 11 so as to forcibly cool the molten metal in the pool 11. I have to. It should be noted that the above is mainly the configuration of the movable die 7, but the fixed die 6 has substantially the same configuration.

The function of the pool structure constructed as described above will be described. First, the fixed mold 2 and the movable mold 3 are clamped,
High-temperature molten metal is poured from the sprue 10 to fill the product cavity 9. Then, the pouring amount of the molten metal is set in advance in the pool part 11
The amount is set so that the molten metal is filled up to the same amount, and the same amount of molten metal is poured every time. In addition to the pouring, the cooling water passage 22
Cooling water is introduced into.

Here, the molten metal that first enters the product cavity 9 is sequentially filled from the end side of the product cavity 9 farther from the sprue 10, and finally is filled in the molten metal pool 11. For this reason, normally, the hot water temperature of the last filled hot water pool portion 11 is the highest and it is in a state where it is hard to solidify. However, in the case of the present invention, the molten metal in the basin 11 is in contact with the mold 7 over a wide area, and the mold 7 around the basin 11 is forcibly cooled by the cooling water passages 22. Therefore, the solidification takes place in substantially the same time as the product cavity 9 and the like, and the release timing can be accelerated. That is, the casting cycle can be increased and the productivity is improved. Further, even if there is a temporary overflow during pouring, the hot water can be temporarily stored in the hot water pool portion 11, and when there is a shortage, it also has a function of supplementing.

Then, the mold is opened at the stage where the surface layer is solidified into a shell shape and the inside is not solidified, and the product is dispensed. The cross section of the basin 11 is circular and has no undercut, and the draft t , T are provided, the mold can be smoothly opened. Moreover, since the molten metal pool 11 is located above the product cavity 9, the unsolidified molten metal inside does not overflow from the molten metal pool 11 when the mold is opened. By the way, since the upper end portion on the product cavity 9 side is filled first, solidification proceeds rapidly, and the unsolidified molten metal inside does not overflow from the upper end of the product cavity 9.

[0024]

As described above, in the hot water pool structure according to the present invention, for example, the molten metal is poured from the spout of a casting apparatus of a fixed type and a movable type, and a shell-shaped solidified layer is formed on the surface layer. At the time of mold opening at the time of mold opening, a hot water pool with a large passage area was provided in the middle of the runner, and the surface layer was solidified at almost the same timing as the product cavity. Can be increased.

Further, it is more effective to forcibly cool the hot water pool by the cooling water passage provided around the hot water pool. By arranging the pool part below the spout and above the product part, it is possible to prevent the problem that the unsolidified molten metal in the interior overflows, and also in the case where there is a temporary overflow during pouring. , It can be temporarily stored in the hot water pool, and when there is a shortage, it also serves as a supplement.

The cross-sectional shape of the basin is substantially circular,
Further, by providing a taper portion having a draft angle at the connection portion between the hot water pool portion and the runner, smooth mold release can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire casting system to which a casting mold having a basin structure according to the present invention is applied.

FIG. 2 is a vertical sectional view of a cavity portion of a casting mold.

FIG. 3 is a front view of the movable type seen from the direction AA of FIG.

FIG. 4 is a side view of the movable type.

5 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

1 ... Casting mold, 2 ... Fixed mold, 3 ... Movable mold, 6 ... Fixed mold, 7 ... Movable mold, 8 ... Design part, 9 ... Product cavity,
Reference numeral 10 ... Gate, 11 ... Hot water pool, 12 ... Vertical runner, 22 ... Cooling water passage, t ... Taper section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunji Matsumoto 1-10-1 Shin-Sayama, Sayama City, Saitama Prefecture Honda Giken Industrial Co., Ltd. Saitama Factory

Claims (3)

[Claims] 1. A casting mold in which molten metal is poured from an upper spout, and the poured molten metal is fed into a product cavity through the runner. Is formed, and the molten metal pool portion is arranged below the molten metal spout and above the product cavity, the molten metal pool structure of the casting mold. 2. The molten metal pool structure for a casting die according to claim 1, wherein a cooling water passage for forcibly cooling the molten metal therein is provided around the molten metal pool portion. The pool structure of the casting mold. 3. The molten metal pool structure for a casting die according to claim 1 or 2, wherein the molten metal pool portion has a substantially circular cross-section, and the molten metal pool portion and the runner are connected to each other. Is a pool structure for a casting die, which is provided with a tapered portion having a draft angle.