JPS6342542B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a mold having an internal cavity;
The present invention relates to a mold device for forging molten metal, which comprises a press die that is inserted into the cavity through an insertion opening formed at the upper end of the mold and pressurizes the molten metal in the cavity. In conventional molten metal forging, the internal pressure of the molten metal is increased by inserting a die as shown in Fig.
The general formula is to bring the molten metal to complete solidification with squeeze solidification while applying a high hydrostatic pressure of 2000 kg/cm ² and raising the freezing point of the molten metal. Therefore, it is necessary for the mold device to have good sealing properties so as not to cause pressure leakage even under such high pressure. A sealing portion d having the same diameter as the inner diameter of the insertion opening c, which extends straight upward with a stepped portion extending radially outward at a portion to be inserted into the insertion opening c of the mold b, is formed, and the sealing portion d into the insertion port c,
Since the sealing method for the insertion port c is generally used, repeated use will cause wear and deformation of the sliding surface between the insertion port c and the sealing part d, making it impossible to achieve a sufficient seal, which will shorten the life of the mold. This is accompanied by the inconvenience of being shortened.

An object of the present invention is to provide a device that eliminates such inconveniences, and in the conventional device described above, the inner diameter of the insertion port is made larger than the outer diameter of the sealing part so that the inner circumferential surface of the insertion port is A gap is formed around the entire circumference between the molten metal and the outer peripheral surface of the seal part, and the molten metal in the cavity overflows into the gap between the lower end of the insertion port and the stepped part at the lower end of the seal part. The invention is characterized in that an overflow port is formed to cause the mold to open, and the degree of opening of the overflow port is gradually decreased as the mold is inserted.

A second invention is characterized in that, in the first invention, a seal ring for sealing the gap is inserted into the opening at the upper end of the gap to the outside.

Next, one example of implementing the present invention will be explained with reference to FIGS. 2 and 3.

In the drawings, reference numeral 1 indicates a mold having an internal cavity 3 connected to an insertion opening 2 at the upper end, 4 indicates a press die inserted into the cavity 3 through the insertion opening 2, and the insertion opening at the upper end of the press die 4. A seal portion 5 is formed which extends straight upward with a stepped portion 7 extending radially outward at the portion to be inserted into the insertion opening 2, and the inner diameter of the insertion opening 2 is made larger than the outer diameter of the seal portion 5. , in this case the insertion port 2
For example, the inner circumferential surface of the sealing part 5 is formed into a tapered surface 6 having a smaller diameter in order toward the bottom, so that a gap 8 having a wedge-shaped cross section over the entire circumference is formed between this and the outer circumferential surface of the sealing part 5. At the same time, a cavity 3 in the mold 1 and a gap 8 between the lower end of the insertion port 2 and the stepped portion 7
An overflow port 9 is formed to communicate with the

Next, to explain its operation, first, molten metal is poured into the cavity 3 in the mold 1, and then the press die 4 is moved down as shown in FIG. do.

At this time, the pressure of the molten metal is increased as the mold 4 moves downward, and a part of the molten metal overflows from the overflow port 9 into the gap 8 as shown in FIG. As the heat dissipation area increases, it solidifies rapidly, thereby forming a type of mold that seals the gap 8, and as the press die 4 moves downward, the opening degree of the overflow port 9 is reduced. Coupled with the fact that the overflow of the molten metal from the cavity 3 is restricted, the molten metal in the cavity 3 is rapidly pressurized without pressure leakage. Note that since the seal portion 5 extends straight upward from the stepped portion 7, the downward movement of the mold 4 is not inhibited even if the molten metal solidifies in the gap 8.

Then, when the internal pressure of the molten metal is increased to a predetermined pressure, the pressing force of the press die 4 is made constant. When this is done, as the molten metal squeezes and solidifies, the press die 4 moves down and the opening of the overflow port 9 is further narrowed, and the effect of the throttle that restricts the overflow of the molten metal is exerted even more strongly, maintaining a high pressure. The state shown in FIG. 3c is reached, and as the molten metal solidifies, the internal pressure decreases and it reaches complete solidification.

In the above embodiment, the tapered surface 6 is formed in the insertion port 2 so that an overflow port 9 is formed between the insertion port 2 and the stepped portion 7 of the seal portion 5, the opening degree of which decreases as the press mold 4 is inserted. However, the present invention is not limited to this, and for example, as shown in FIG.
may be formed. However, in this case, the opening degree of the overflow port 9 is not reduced to a state where the throttling effect is exerted unless the press die 4 is inserted considerably, so that there remains some problem in sealing performance during insertion.

On the other hand, the type in which a tapered surface 6 is formed in the insertion port 2 is advantageous because the opening degree of the overflow port 9 can be sufficiently reduced even during insertion due to the inclination of the tapered surface 6.

However, even with this, if the amount of molten metal in the cavity 3 exceeds the specified amount due to variations in the amount of poured metal, the mold 4
At the initial stage of insertion, molten metal exceeding the volume of the cavity 8 may overflow to the outside.

The above-mentioned second invention eliminates this inconvenience, and as shown in FIG. 5, a seal ring 12 is inserted into the opening 11 at the upper end of the cavity 8 to seal it. In the illustrated example, the seal ring 12 is a movable mold that can be freely inserted into and removed from the opening 11, and is biased downward in the insertion direction by a spring 13 inserted between the seal ring 12 and the pressing mold 4. Even if a large amount of molten metal is poured, the molten metal may press the seal ring 12 against the spring 13 as shown in FIG. 6 when the mold 4 is inserted.
The molten metal in the cavity 3 overflows into the gap 8 while pushing up against the pressure, and the extra molten metal flows into the gap 8 by the amount that the seal ring 12 is pushed up and is solidified. As a result, the insertion position of the press die 4 becomes constant and the product dimensions are made uniform, and the opening of the overflow port 9 is also reduced to a predetermined constant opening, ensuring that the throttling effect is exerted. be done.

As described above, according to the present invention, between the insertion opening formed in the mold and the seal part formed in the press mold, a gap spanning the entire circumference and an overflow port whose opening degree decreases as the press mold is inserted are formed. However, when inserting the mold, the insertion opening is sealed by the seal ring effect caused by the molten metal that overflows into the gap from the overflow opening and solidifies, and by the throttling effect caused by the reduction in the opening of the overflow opening. There is no sealing failure due to wear or deformation, unlike the conventional type that seals by sliding on the parts.
The life of the mold can be significantly extended, and the second
According to the invention, since the opening of the gap is sealed by the seal ring, there is an effect that the molten metal does not overflow from the opening to the outside due to variations in the amount of poured metal.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of a conventional device, FIG. 2 is a cutaway side view of an example of the device of the present invention, and FIGS. 3a, b, and c.
4 is an enlarged cross-sectional side view of the main part to explain its operation, and FIG. 4 is an enlarged cross-sectional side view of the main part showing another embodiment.
FIG. 5 is a cross-sectional side view of an example of the embodiment of the second invention, FIG. 6 is an enlarged cross-sectional side view of essential parts for explaining its operation, and FIG. 7 is a diagram showing pressure changes in molten metal forging. 1...Mold, 2...Insertion port, 4...Press mold, 5...
...Seal portion, 8...Gap, 9...Overflow port, 11...
...Opening, 12...Seal ring.

Claims (1)

[Scope of Claims] 1 Consists of a mold having an internal cavity, and a press die that is inserted into the cavity through an insertion opening formed at the upper end of the die to pressurize the molten metal in the cavity. In the case where the part of the upper end that is inserted into the insertion port has a stepped portion radially outward to form a seal portion that extends straight upward, the inner diameter of the insertion port is larger than the outer diameter of the seal portion. The gap is enlarged to form a gap around the entire circumference between the inner peripheral surface of the insertion port and the outer peripheral surface of the sealing part, and the molten metal in the cavity is formed between the lower end of the insertion port and the step part. A mold device for forging molten metal, characterized in that an overflow port is formed to cause the molten metal to overflow into the gap, and the opening degree of the overflow port is sequentially reduced as the die is inserted. 2. The mold device for molten metal forging according to claim 1, wherein the inner circumferential surface of the insertion opening is formed into a tapered surface with a smaller diameter in a downward direction. 3 Consists of a mold having an internal cavity, and a press die that is inserted into the cavity through an insertion opening at the upper end formed in the mold and pressurizes the molten metal in the cavity, A seal portion is formed that extends straight upward with a stepped portion extending radially outward in the insertion portion, and the inner diameter of the insertion port is made larger than the outer diameter of the seal portion. A gap is formed around the entire circumference between the circumferential surface and the outer circumferential surface of the seal portion, and an overflow is formed between the lower end of the insertion port and the stepped portion to cause the molten metal in the cavity to overflow into the gap. A sealing ring is inserted into the opening at the upper end of the opening that opens the gap to the outside, in which a flow opening is formed and the opening of the overflow opening is gradually reduced as the mold is inserted. A mold device for molten metal forging, which is characterized by: 4. The mold device for molten metal forging according to claim 3, wherein the seal ring is movable in the vertical direction and is biased downward by a spring.