JPS6130274A - Vacuum die casting device - Google Patents

Abstract

PURPOSE:To prevent the generation of a cavity owing to the intrusion of foam in a molten metal by moving a piston which is inserted into a metal slleve from the top end side thereof and controls small the space for receiving the molten metal up to a bottom pouring runner while holding the moltem metal inserted between said piston and plunger. CONSTITUTION:An auxiliary metal sleeve 24 is provided in the position extended from the end part on the bottom pouring runner 20 side of the metal sleeve 21 and the position 26 for receiving the molten metal is provided freely movably into and out of the inside of the sleeve 24 toward a pouring port 22. The piston 26 is pushed out toward the port 22 side to control the space for receicing the molten metal in the sleeve 21 and is so constructed that the piston can be retreated together with the molten metal (a) to the position for opening the runner 20 when the plunger 23 is pushed in.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a vacuum die-casting device that reduces the pressure inside a cavity formed by a fixed mold and a movable mold, and pushes up molten metal from the bottom of the cavity. .

(Prior Art) In a conventional vacuum die casting device, as a mechanism for filling a cavity with molten metal, a molten metal is placed at the bottom of a cavity 3 formed by a fixed mold 1 and a movable mold 2, as shown in FIG. A channel 4 is formed, a metal sleeve 5 is provided at the bottom of the fixed mold leading to the runner 4, a pouring port 6 is formed at the end of the metal sleeve 5, and a plunger 7 is installed inside the sleeve 5. is inserted into the sleeve 5 through the spout 6, and by pushing in the plunger 7 while reducing the pressure inside the cavity 3, the molten la is pushed up from the runner 4 into the cavity 3.

(Problems to be Solved by the Invention) In such conventional vacuum die casting equipment, due to the thickness of the mold and the presence of a mold support material, the length of the metal sleeve 5, that is, the length from the pouring port 6 to the runner 4 cannot be shortened, and therefore, normally a molten metal pouring space several times the volume of molten metal required to be poured into the cavity 3 is formed in the metal sleeve 5.

When the molten metal poured into the metal sleeve 5 is sucked up by reduced pressure and pushed up by the plunger, the air inside the metal sleeve 5 is drawn into the molten metal at the runner 4 position, and many cavities are formed in the cast product. It was impossible to prevent this from occurring. For this reason, especially in the case of aluminum alloy castings, when heat treatment is applied, the air inside the channel expands and the surface swells.
There was a problem that dimensional changes occurred.

In view of these conventional problems, the present invention minimizes the amount of air remaining inside the metal sleeve when pushing the molten metal up into the cavity using a plunger from inside the metal sleeve, thereby preventing air entrainment and producing die casting without cavities. The purpose of this invention is to provide a vacuum die-casting device that allows casting products to be obtained.

(Structure of the Invention) In order to achieve the above-mentioned objects, the present invention provides a vacuum die-casting machine similar to the conventional machine described above, in which an auxiliary metal sleeve is provided at a position where the end of the metal sleeve on the push-up runner side is extended. , is provided with a piston for receiving molten metal that can freely move in and out from inside the auxiliary metal sleeve toward the pouring port, and pushes the piston toward the pouring port to regulate the receiving space in the metal sleeve and pouring the molten metal by pushing the plunger. At the same time, the push-up runner is retracted to the position where it is opened, and the piston is pushed in from the tip of the metal sleeve to approach the pouring spout so that the molten metal can be poured while controlling the volume of the molten metal receiving portion. The molten metal is sealed between the plunger and the piston when the plunger is pressed in, with almost no air entering the piston.

(Example) Next, an example of implementing the present invention will be described with reference to FIGS. 1 to 4.

In the figure, 10 is a fixed type, and 11 is a movable type. The fixed mold 10 is fixed to a fixed support metal fitting 12 fixed to a machine base (not shown), and the movable mold 11 is attached to a movable support metal fitting 14 that is reciprocated toward the fixed support metal fitting 12 by a fluid pressure cylinder 13 with a spacer 15a'. , 15b.

Both molds 10 and 11 are joined to each other so that a cavity 16 is formed therebetween.

An overflow part 17 is formed in the movable mold 11 so as to communicate with the upper part of the cavity 16, and an intake passage 18 for decompression is formed in communication with the overflow part 17. The pressure reduction mechanism is connected. Reference numeral 19 denotes a valve that opens and closes the reduced pressure intake passage 18.

Further, a push-up runner 20 is formed in the fixed mold 10 and communicates with the bottom of the cavity 16, and a metal sleeve 21 is attached in a substantially horizontal arrangement so as to communicate with the lower end of the push-up runner.

The metal sleeve 21 is provided by penetrating the fixed mold 10, and has a tip opening at the joint surface on the movable mold side of the fixed mold 10, a rear end extending to the back of the support fitting 12 of the fixed mold 10, and a pouring hole on the upper surface of the rear end. 22 is formed. A plunger 23 is inserted through the rear end opening of the metal sleeve 21, and is inserted and removed using a fluid pressure cylinder (not shown).

On the other hand, the movable mold 11 is provided with an auxiliary metal sleeve 24 extending therethrough. This auxiliary metal sleeve 2
4 is disposed on an extension of the metal sleeve 21 of the fixed mold 10, so that when both molds 10 and 11 are joined together, the distal end side is continuous with the metal sleeve 21. Furthermore, a piston 26 for receiving hot water is housed astride a piston guide hole 25 formed in the rear end side spacer 15b of this auxiliary metal sleeve 24. The piston 26 is inserted into the metal sleeve 21 and closes its end with its end face, and closes the push-up runner 20 with its circumferential face. This piston 26 is attached to the metal sleeve 21 with a fluid pressure cylinder 27 fixed to the movable support fitting 14.
It is made to be pushed inward toward the end on the pouring port 22 side.

Next, the operation of the device configured as described above will be explained. First, as shown in FIG. Uke creates space. In this state, a predetermined amount of molten metal a is poured from the pouring port 22.

After injecting the molten metal, the plunger 23 is pushed out toward the piston 26 using a fluid pressure cylinder, as shown in FIG. And the plunge? -23 is moved toward the piston 26 side, the molten metal level rises and air is discharged from the pouring port 22, and if the amount of molten metal poured is too large, excess molten metal is also flowed out. In this way, when the tip end surface of the plunger 23 has passed through the pouring port 22, the molten metal a is sandwiched between the plunger 23 and the piston 26 with almost no air between them.

In addition, this state of sandwiching the molten metal a is similar to that in cavity 1.
This can be achieved by setting the length of the piston 26 or the amount of extrusion in advance in accordance with the required amount of poured metal according to the amount of melted metal 6.

Then, the valve 19 is opened in conjunction with the operation of the plunger 23, and the pressure reducing mechanism removes the air in the cavity 16 to reduce the pressure, and at the same time, the plunger 23 is further pushed out, and as the molten metal a is pushed in, the piston 26 is pushed back.

In this way, the piston 26 is pushed back, and as shown in FIG.
6 stops returning, the plunger 23 is further pushed out, and the molten metal a is filled into the cavity 16 through the push-up runner 20. In addition, it prevents it from getting stuck.

After injecting the molten metal into the cavity 16 in this way, the movable mold 11 is moved to open the cavity 16 and the casting is taken out as it solidifies, and then the state is returned to the state shown in Fig. 1 and the operations are repeated sequentially to perform casting. .

(Effects of the Invention) The vacuum die-casting device of the present invention is constructed as described above, and is inserted into the metal sleeve from the tip side, and the molten metal receiver restricts the volume of the space to a small size and allows the molten metal to flow between the piston and the plunger. By moving the molten metal to the push-up runner in a sandwiched state, there is almost no air flowing into the pre-depressurized cavity when pouring the molten metal, which almost completely eliminates the formation of blowholes due to the inclusion of air bubbles. This makes it possible to obtain a product with a high N degree without deformation even when aluminum alloy castings are subjected to heat treatment.

[Brief explanation of drawings]

1 to 4 are longitudinal cross-sectional views showing different operating states of an apparatus according to an embodiment of the present invention, and FIG. 5 is a longitudinal cross-sectional view of an example of a conventional vacuum die-casting apparatus. a... Molten metal, 10... Fixed type, 11.
...Movable type, 16...Cavity, 18
...Intake passage for pressure reduction, 19...Valve, 20...
...Oshiage yudo, 21...Metal sleeve, 2
2...Pouring spout, 23...Plunger, 24...Auxiliary metal sleeve, 26...
··piston.

Claims (1)

[Claims] (1) An intake mechanism that communicates with the inside of a cavity formed by a fixed type and a movable type and reduces the pressure inside the cavity;
A push-up runner is opened in communication with the bottom of the cavity, and a metal sleeve is provided in communication with the push-up runner for extruding the solution melt, and a pouring port is opened at the end of the metal sleeve and poured into the metal sleeve. A vacuum die casting device in which a plunger is inserted to push out hot water in a metal sleeve poured from a sprue to a push-up runner, and an auxiliary metal sleeve is provided at an extension of the push-up runner side end of the metal sleeve. , is provided with a piston for receiving molten metal that can freely move in and out from inside the auxiliary metal sleeve toward the pouring port, and pushes the piston toward the pouring port to regulate the receiving space in the metal sleeve and pouring the molten metal by pushing the plunger. A vacuum die-casting apparatus characterized in that the press-up runner is also retracted to a position where the push-up runner is opened.