JP3305984B2 - Gravity casting method and gravity casting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method and a casting apparatus for gravity casting aluminum castings by filling a product cavity and a feeder cavity of a mold with a molten metal such as aluminum.

[0002]

2. Description of the Related Art As an apparatus for gravity casting an aluminum casting or the like, there is, for example, an apparatus provided with a mold 20 and a runner 21 shown in FIG. The mold 20 has a plurality of product cavities 22 therein.
Each of the feeder cavities 23 is formed above the product cavities 22 so as to communicate with the product cavities 22. A common communicating hot runner 24 is formed at the bottom of each product cavity 22 and communicates with the hot runner 25 of the hot runner section 21.

The molten metal poured from the spout 26 at the upper end of the runner 21 goes down the runner 25 as shown by the arrow in FIG. 4 and fills the continuous runner 24 of the mold 20 from the weir 27 and further communicates. After being poured into each product cavity 22 from the runner 24 and filled into the product cavity 22, the product cavity 22
Then, it is poured into the riser cavity 23 and filled into the riser cavity 23. When the molten metal is filled into each of the product cavities 22 and the feeder cavities 23 and pouring is completed, solidification of the filled molten metal starts and a casting is gravity-cast in the product cavities 22. When the molten metal solidifies in the product cavity 22 and contracts in volume, the molten metal in the feeder cavity 23 flows down to the product cavity 22 by gravity, and the product cavity 2
2. Prevents the occurrence of sink nests within 2.

[0004]

In the case of the gravity casting apparatus as described above, the molten metal is filled in the order of a runner, a weir, a mold runner, and a product cavity from a gate of a runner part, and finally is pushed. Since the hot water cavity is filled, the temperature of the molten metal at the time of filling the product cavity and the feeder cavity is higher on the product cavity side and lower on the feeder cavity side. That is, since the molten metal flows into the feeder cavity while contacting the product cavity and the core and radiating heat while flowing from the runner to the product cavity, the temperature distribution at the time when the molten metal is filled in the feeder cavity, High distribution. As a result, the molten metal on the side of the feeder cavity, where the temperature of the molten metal is lower after the filling of the molten metal, solidifies earlier than the molten metal on the product cavity side. Then, a reversal phenomenon occurs in which the molten metal on the product cavity side is sucked up due to volume shrinkage due to solidification of the molten metal in the riser cavity.

As a solution to the above problem, the heat capacity of the molten metal filled in the riser cavity is set excessively by expanding the volume of the riser cavity, thereby suppressing the solidification speed of the molten metal filled in the riser cavity. In addition, it has been practiced to ensure a feeder effect on the product cavity by the molten metal in the feeder cavity. However, there has been a problem that the mold is enlarged due to an increase in the volume of the feeder cavity of the mold, and a problem that the yield of the product is deteriorated due to an increase in the amount of molten metal used and the production cost of the casting is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gravity casting method and a gravity casting method in which a molten metal temperature distribution between a product cavity and a riser cavity can be made normal and good gravity casting can be performed without increasing the volume of a riser cavity of a mold. It is to provide a device.

[0007] In addition, there has been proposed a push-up casting mold in which a runner and a feeder portion are communicated by an auxiliary runner (Japanese Utility Model Laid-Open No. 57-76948). Lack of stability has been pointed out, and problems to be solved in terms of practicality remain.

[0008]

SUMMARY OF THE INVENTION The method of the present invention communicates with the bottom of a product cavity formed in the lower portion of a mold, and
The gate of a product runner that pushes molten metal from below to the bitty.
And communicated with the product cavity at the top of the mold
A feeder that pours molten metal into the formed feeder cavity from above
The pouring device for pouring water into the gate of the hot water runner in sequence
And attached to the mold, the filled molten metal from below the product cavity by gravity casting by filling a molten metal from above the feeder cavity after the filling is intended to achieve the above object.

As described above, the product cavity is provided from below.
The molten metal is poured into the feeder cavity from above by dividing the molten metal into two parts before and after, so that the temperature of the molten metal in the riser cavity filled later is higher than the temperature of the molten metal in the product cavity filled earlier. Thus, the feeder effect at the time of solidification of the product cavity by the melt in the feeder cavity can be obtained stably. This stable feeder effect eliminates the need to increase the volume of the feeder cavity.

[0010] The apparatus of the present invention further comprises a product cavity;
Communicating with the bottom of the product cavity, the product mold and a product runner to push up pouring the molten metal from below the molding cavity
When the feeder head cavity top and communicating the product cavity, and a feeder head mold having a feeder runner for pouring the molten metal from above the feeder cavity, and a sprue of the product runner,
Inject the pouring water into the sprue of the hot water mold of the hot water mold in order.
And a hot water device .

[0011] In the apparatus of the present invention, it is possible to automate gravity casting by providing a pouring device for sequentially pouring the spout of the product runner and the spout of the feeder runner of the feeder mold. Desirable above.

When the product mold and the feeder mold in the apparatus of the present invention are separate, the feeder mold is installed on the product mold, and the lower product cavity and the upper feeder cavity communicate with each other. As the product runner for pouring the molten metal into the product mold, the runner of the existing pouring device may be applied. As the feeder mold, a shell structure having a feeder cavity inside and a feeder channel on the upper surface may be applied. When a plurality of feeder cavities are formed in a horizontal row in the feeder mold, the feeder runner is formed into a shape that is branched from one gate to a plurality of feeder cavities, and a plurality of molten metal from one gate is provided. It is desirable to divide the hot water into the feeder cavity and pour it.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS. 1 and 2 are cross-sectional views schematically showing a gravity casting apparatus for explaining the method of the present invention.
FIG. 3 is a cross-sectional view for explaining a specific structure example of the gravity casting apparatus.

The gravity casting apparatus shown in FIG.
The feeder mold 1b having the feeder cavity 3 is overlaid on the product mold 1a having The runner section 8 is connected to the product mold 1a of the mold 1, and a common pouring device 11 is attached to the product mold 1a and the feeder mold 1b. The pouring device 11 pours the same molten metal 4 into both the product mold 1a and the feeder mold 1b one after another.

For example, a plurality (five in the drawing) of product cavities 2 of the product mold 1a are formed in a horizontal line, and a common product runner 5 communicates with the bottom of each product cavity 2, and the product runner 5 The product runner 6 of the runner section 8 communicates with the end. The existing runner similar to FIG. 4 can be applied to the runner 8.

A plurality of feeder cavities 3 of the feeder mold 1b are formed in a horizontal row corresponding to the plurality of product cavities 2 of the product mold 1a, and a lower end opening of each feeder cavity 3 is formed in the product cavity of the product mold 1a. 2 Connect to the upper part. A feeder runner 9 is formed on the upper surface of the feeder mold 1b, and the molten metal 4 is poured into each feeder cavity 3 via the feeder runner 9.

The gravity casting of the present invention is performed in two steps shown in FIGS. 2 (A) and 2 (B). First, the molten metal 4 is supplied from the pouring device 11 to the gate 7 of the runner section 8, and the molten metal 4 is caused to flow down the product runner 6 of the runner section 8 and flow to the product runner 5 of the product mold 1a. As shown in FIG. 2 (A), the molten metal 4 is poured into the product cavities 2 from the product runner 5 by push-up and filling. At the timing before and after the end of the filling, the pouring device 11
The pouring direction is changed while the nozzle is continuously operated.
The molten metal 4 is supplied to the feeder runner 9 by switching to 0. The molten metal 4 supplied to the feeder passage 9 flows down from the upper end opening of each feeder cavity 3 into the feeder cavity 3 as shown in FIG. When the filling of the molten metal in each riser cavity 3 is completed, the pouring of the pouring device 11 is stopped.

As described above, the molten metal 4
And then the molten metal 4 is continuously placed in the feeder cavity 3.
Is filled, the path of the molten metal 4 before filling the product cavity 2 and the path of the molten metal 4 until filling the feeder cavity 3 can be made the same. The temperature is equalized. Further, since the molten metal 4 is filled into the product cavity 2 first, the molten metal solidification in the two cavities 2 and 3 tends to occur earlier in the product cavity 2. As a result, even if the volume of the feeder cavity 3 is not increased, the product cavity 2 surely solidifies the molten metal earlier and causes volume shrinkage. Supplemented, gravity casting is performed normally. Further, the volume of the feeder cavity 3 does not have to be increased, in other words, the volume of the feeder cavity 3 can be reduced, and the reduction in the volume improves the product yield of the casting. Actually, when the feeder mold 1b of FIG. 3 is used, the product yield by the method of the present invention is 70 to 75%.
This is 10% or more better than the product yield of 50-60% when the same casting is cast by the conventional method of FIG.

Further, if a pouring device 11 capable of automatically pouring the molten metal into the sprue 7 on the product mold 1a side and the sprue 10 on the feeder mold 1b side is used, the inside of the ladle of the pouring device 11 is used. Feeder cavity 3 of feeder mold 1b
And gravity casting can be performed more normally and stably.

Next, a specific example of the feeder mold 1b shown in FIGS. 3A to 3C will be described. The hatched portion in FIG.
a communicates with the upper end opening of the product cavity 2. A plurality of feeder cavities 3 are arranged in a horizontal line, and a feeder runner 9 is formed so as to communicate with each upper end opening. The feeder runner 9 is a shell groove having an inclined bottom surface.
A pouring port 12 is provided at a location, and a feeder channel 9 branched from the pouring port 12 toward the upper end opening of each feeder cavity 3 is formed. Pouring device 1 in pouring port 12 of hot water runner 9
When the molten metal is supplied from 1, the molten metal flows under its own weight in the feeder runner 9, branches off, is supplied to each feeder cavity 3 in an appropriate amount, and is filled into each feeder cavity 3.

[0021]

According to the gravity casting method of the first aspect,
After the product cavity is filled with the molten metal, the molten metal is continuously filled into the riser cavity, so that the temperature distribution of the molten metal at the time of completion of the molten metal filling of the product cavity and the riser cavity becomes an ideal high temperature on the product cavity side, The solidification of the molten metal in the product cavity is faster than the solidification of the molten metal in the feeder cavity, and the volume shrinkage during solidification of the molten metal in the product cavity is reliably compensated for by the riser of the molten metal in the riser cavity, and gravity casting is normal. Done in In addition, normalization of gravity casting makes it possible to reduce the volume of the feeder cavity and reduce the size and weight of the casting apparatus, and to improve the product yield of castings by reducing the volume of the feeder cavity, thereby reducing manufacturing costs.

According to the gravity casting apparatus of the second aspect, the existing casting mold can be applied to the product mold and the equipment of the product runner for pouring the molten metal into the casting mold. Equipment can be provided. Further, since the molten metal is poured into the feeder cavity from the feeder mold formed in the feeder mold, when there are a plurality of feeder cavities, the feeder can be moved from one tap to a plurality of feeder cavities. By branching to
Pouring into each of a plurality of feeder cavities can be easily performed.

In addition, by using a pouring device capable of automatically pouring continuously at two points, a sprue of a product mold, a sprue of a feeder mold, and a sprue of a feeder mold, immediately after pouring into the product mold. It is easy to fill the molten metal of a sufficiently high temperature in the ladle of the pouring device into the riser cavity of the riser mold, and it is possible to provide a gravity casting device capable of more stable gravity casting.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a gravity casting apparatus for explaining a method of the present invention.

FIG. 2 is a partial cross-sectional view at the time of gravity casting of the apparatus in FIG.
FIG. 3B is a cross-sectional view of the product cavity when the molten metal is filled, and FIG.

3A is a plan view showing an embodiment of a feeder mold in the apparatus of the present invention, FIG. 3B is a cross-sectional view taken along line T ₁ -T _{1 of} FIG. 3A, and FIG. 3C is T _{2 of} FIG. FIG. 4 is a sectional view taken along line −T ₂ .

FIG. 4 is a sectional view schematically showing a conventional gravity casting apparatus.

[Description of Signs] 1 Mold 1a Product mold 1b Feeder mold 2 Product cavity 3 Feeder cavity 4 Melt 5 Product runner 6 Product runner 7 Gate 9 Feeder runner 10 Gate 11 Injection device

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 23/00 B22C 9/06 B22C 9/08

Claims (2)

(57) [Claims] 1. A product cavity formed in a lower part of a mold.
Into the product cavity and push up the molten metal from below into the product cavity
The product key on the top of the mold and the gate of the product runner
Up the feeder cavity formed in communication with the cavity
Pouring the molten metal from
A gravity casting method comprising: attaching a pouring device for pouring hot water to the mold ; filling the product cavity with the molten metal from below; and filling the feeder cavity with the molten metal from above after the filling and performing gravity casting. . 2. A product cavity, communicating with the bottom of the mold cavity, and product mold having a product runner to push up pouring the molten metal from below the product cavity, feeder head cavity top and communicating the molding cavity And a feeder mold having a feeder for pouring the molten metal into the feeder cavity from above, a gate of the product runner, and a gate of the feeder of the feeder mold,
A gravity pouring device, comprising : a pouring device for pouring the molten metal in sequence .