JPH04309448A - Die casting machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting machine that injects molten metal into the cavity of a clamped mold and solidifies the molten metal to produce a product.

0002

[Prior art] As a type of this type of die casting machine,
Pneumatic die-casting machines that inject molten metal into a mold cavity using air pressure are known, and conventionally proposed pneumatic die-casting machines are generally configured as follows. That is, among the upper and lower cylinder platens and fixed platen whose four corners are connected by tie rods, a fixed mold is attached to the lower fixed platen, and a movable platen moves up and down along the tie rods. is equipped with a movable mold. A cavity is formed at the joint between the two clamped molds. Further, a mold clamping cylinder is attached to the upper cylinder platen to clamp the mold by lowering the movable platen with the movable mold. A U-shaped stalk in which molten metal is stored is disposed below the machine base that supports the fixed platen, with an opening at one end communicating with the cavity. The other end of a pipe having an air valve and having one end connected to an air source is connected to the opening at the other end. Such a stalk is fixed by being immersed in molten metal in a heat insulating furnace fixed to the floor side, and the molten metal in the stalk is kept warm by the molten metal in the heat insulating furnace. Further, a shutter is provided at the center of the stalk, and is moved by a solenoid or the like to open and close the shutter to connect or disconnect the stalk and the heat-retaining furnace.

With this structure, after the movable platen is lowered by the mold clamping cylinder to clamp the mold, the air valve is opened and the shutter is closed to apply air pressure to the molten metal in the molten metal container. Since the molten metal in the stalk is injected into the mold cavity by this air pressure, the shutter is closed with the molten metal filling the cavity. After this, after the molten metal in the cavity solidifies and becomes a product, when the movable platen is raised, the movable mold holds the product and rises, so the product is pushed out of the cavity with an extrusion pin and taken out of the machine. This completes one casting cycle. When the shutter is opened, the molten metal in the insulating furnace moves into the stalk and is replenished with molten metal.

0004

[Problems to be Solved by the Invention] However, in such conventional pneumatic die casting machines, the stalk and pouring device are constantly immersed in the molten metal and exposed to high temperatures. There is a problem that the material is easily deteriorated, and especially when the temperature is as high as 700 degrees as in the case of the molten metal being Mg, when air pressure is applied, not only is the material deteriorated greatly,
It cannot be said that there is no risk of explosion, making it difficult to put it into practical use.

The present invention was developed in view of the above points, and it is possible to prevent the stalk and pouring device from being constantly immersed in molten metal, thereby eliminating the risk of explosion, and to improve mold clamping and sealing. The object of the present invention is to provide a pneumatic die-casting machine that can perform the following operations with a single member.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a die-casting machine with a mold clamping station equipped with a mold clamping device that clamps a mold by lowering a movable platen with respect to a fixed platen. , a pressurized container that is installed on the lower surface of the fixed platen and can introduce gas and opens to the upper surface of the fixed platen, a pouring device that supplies molten metal to the pressurized container, and a device that is connected between the mold clamping station and the outside of the machine. a mold opening/closing unit comprising a movable trolley, a fixed mold mounted on the trolley so as to be able to move up and down, and a movable mold that can be opened and closed;
A stalk that is fixed to the fixed mold and enters the pressurized container by descending of the mold opening/closing unit that has entered the mold clamping station and communicates the molten metal pressurizing device with the mold cavity; and a heating device that heats the stalk. has been established.

[0007]

[Operation] After supplying molten metal into the pressurized container with the pouring device,
A mold opening/closing unit consisting of both molds in a mold matching state and a cart on which they are mounted, and a stalk that was fixed to the fixed mold and heated during pouring, are moved into the mold clamping station, and both molds are removed. When lowered and seated on the fixed platen,
When the stalk is inserted into the pressurized container and the movable platen is lowered by the clamping cylinder in this state, the mold is clamped with a large force. Therefore, when pressurized gas is introduced into the pressurized container, the molten metal in the pressurized container is injected into the mold cavity through the inner hole of the stalk. After the molten metal in the mold cavity has solidified, the movable platen is raised to release the mold clamping by the mold clamping cylinder, both molds are raised and the stalk is removed from the pressurized container, and the mold opening/closing unit is moved to the outside position. Move to. Then, after the movable mold is raised significantly to open the mold, the product is taken out of the extruder from the cavity.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially cutaway front view showing an embodiment of a die casting machine according to the present invention. In the figure, a fixed platen 2 is provided above a pit 1 provided below the floor surface, supported by the peripheral edge of the pit 1, and the upper ends of tie rods 3 installed upright at the four corners of the fixed platen 2 are provided. The link housing 4 is fixed with a nut 5. The lower end of the piston rod 7 of the mold clamping cylinder 6, which is provided in the center of the link housing 4 so as to be movable up and down through the link housing 4, is fixed to a movable platen 9. As shown in the figure, a toggle link mechanism 8 is provided between both sides of the mold clamping cylinder 6, the link housing 4, and the movable platen 9, so that the movable platen 9 can be moved to the tie rod 3 by moving the mold clamping cylinder 6 forward or backward. It is configured to move up and down guided by.

Mold clamping station 1 configured as described above
A trolley 12 is provided on a rail 11 attached to the side of the mold clamping station 10 so as to be movable toward and away from the mold clamping station 10, and a plunger pump 1 is mounted on the trolley 12.
3, the hot water supply unit 14 is equipped with a telescopic link 15.
Supported through. Reference numeral 16 denotes a telescopic bellows with a concave cross-section that connects the hot water supply unit 14 and an inert gas diffusion prevention frame 47 with a concave cross-section provided on the side of the mold clamping station 10. A horizontal hot water supply pipe 17 with one end inserted into the hot water supply unit 14 is disposed, and a vertical hot water supply port 18 is attached to the tip of this hot water supply pipe 17. On the other hand, the fixed platen 2
An induction heater 1 as a heating element is installed on the bottom surface of the
A cylindrical pressurized container 21 with an upwardly opened bottom and covered with a heat insulating board 20 made of asbestos or the like is fixed by a plate portion 21a, and this pressurized container 21 is filled with high-pressure N2. A container in which gas or the like is stored is connected by a pipe having an injection valve 22. In addition, pressure vessel 2
1 is provided with a thin heat insulating layer formed by spraying zirconia, for example, to prevent molten metal from penetrating. Since the pressurized container 21 is heated by the induction heater 19, the temperature of the pressurized container 21 itself does not increase much, and even if there is a heat insulating layer in the middle, the molten metal in the pressurized container 21 is sufficiently heated. be able to. Further, the fixed platen 2 is provided with an opening 2 a corresponding to the opening of the pressurized container 21 . By doing this, the hot water supply unit 14 is moved forward while the molten metal is poured into the hot water supply unit 14 and the link 15 and the bellows 16 are expanded and contracted, and the hot water supply port 18 is moved forward as shown by the chain line and lowered into the pressurized container 21. After that, by operating the plunger pump 13, the molten metal is supplied into the pressurized container 20. Further, by opening the injection valve 22, the inside of the pressurized container 20, which is made airtight by a structure described later, is pressurized.

Furthermore, on the opposite side of the hot water supply device 23 to the mold clamping station 10, a mold opening/closing unit, generally designated by the reference numeral 24, is provided. That is, on a rail 25 laid in the pit 1, a cart 26 formed in a U-shape in side view is provided so as to be movable between the illustrated position and the inside of the mold clamping station 10. A pair of lifting cylinders 27 are vertically fixed to both ends of the cart 26, and a U-shaped mold stand 29 is fixed to the working end of the piston rod 28 of these lifting cylinders 27. has been done. Furthermore, a fixed mold 30 is fixed on the mold stand 29, and a pair of mold opening/closing cylinders 31 are fixed on both sides of the mold stand 29. 32 is the upper plate 33
The movable mold is divided into a middle plate 34 and a lower plate 35 and joined together.The working end of a piston rod 36 of a mold opening/closing cylinder 31 is fixed to the upper plate 33. The movable mold 32 is configured to open and close relative to the fixed mold 30 by moving forward and backward.

Reference numeral 37 denotes a cavity formed at the joining surface of both molds 29 and 32 which are matched by the mold opening/closing cylinder 31, and this cavity 37 has a stalk 38 fitted into the hole of the fixed mold 30. It communicates with the inner hole of the molten metal through a U-shaped recessed molten metal reservoir 39, and
The stalk 38 moves the mold opening/closing unit 24 into the mold clamping station 10 using the trolley 26 and retreats the piston rod 36 of the lifting cylinder 31, thereby moving the pressurized container 2
It is configured to be inserted into 1. In this case, the mold stand 29 is seated on the fixed platen 2, and the mold 30
, 32 are clamped by the mold clamping cylinder 6, and in conjunction with the sealing by the sealing material 40, the airtightness within the pressurized container 21 is maintained. Further, below the stalk 38 located outside the machine, an induction heater 43 is provided as a stalk heating device that is fixed to the piston rod 42 of the lifting cylinder 41 and moves up and down as the piston rod advances and retreats. The stalk 38 is configured to be heated by engaging the stalk 38. Here, an induction heater is used as the stalk heating device, so
Even if some molten metal solidification remains around the stalk 38, it will easily melt. A protective portion 43a is provided between the induction heater 43 and the piston rod 42. In addition, when heating the stalk 38,
The induction heater 43 is kept stationary downward,
It is also possible to lower the stalk 38 together with the mold opening/closing unit 24.

Further, an extrusion pin 46 with its tip facing the cavity 37 is fixed to the piston rod 45 of the extrusion cylinder 44 supported by the upper plate 33 of the movable mold 32, and is used to advance the piston rod 45. As a result, the product solidified within the cavity 37 is extruded from the cavity 37. 47 has a concave cross section and extends from the end of the water heater 23 to the end of the mold opening/closing unit 24 in the heating section of the stalk 38 to prevent the inert gas from dissipating. This is the frame of This inert gas diffusion prevention frame 47 is opened upward, and is surrounded by side plates and a bottom plate having an appropriate height, so that a gas such as sulfur hexafluoride, etc. If you fill it with heavy inert gas, it will not escape outside the frame 47.

The operation of the die casting machine constructed as above will be explained. Fill the frame 49 with inert gas,
After pouring molten metal, for example Mg, into the hot water supply unit 14 in the illustrated state, the hot water supply unit 14 is moved to the mold clamping station 1.
When pushed in the 0 direction, the hot water supply unit 14 moves together with the cart 13 while contracting the bellows 16, and the hot water supply port 18 moves to the position shown by the chain line 18A in the figure. When 14 falls,
The hot water supply port 18 is connected to the pressurized container 21 as shown by the chain line 18B in the figure.
inserted inside. Therefore, if the plunger pump 13 is operated without raising the hot water supply port 18 little by little, the molten metal in the hot water supply unit 14 is supplied into the pressurized container 21 by a little more than one shot. During hot water supply, the induction heater 43 is raised together with the piston rod 42 of the lifting cylinder 41 to preheat the stalk 38.

Then, after returning the water heater 23 to the position shown in the figure in the reverse operation and lowering the induction heater 43 to the position shown, the mold opening/closing unit 24 in the mold matching state is opened as shown in the figure. It is moved into the mold clamping station 10 together with the trolley 26. And lifting cylinder 2
When the piston rod 28 of No. 7 is retreated, the stalk 38
is inserted into the pressurized container 21 until the tip thereof contacts the bottom surface of the pressurized container 21, and both molds 30 and 32, which are still aligned, are lowered and the mold table 29 is moved to the fixed platen. Since the movable platen 9 is seated on the upper surface of the platen 2, when the movable platen 9 is lowered by the operation of the mold clamping cylinder 6 and the toggle link mechanism 8, the molds 30 and 32 are clamped with a large force. Therefore, the seating surface of the fixed mold 30 is pressed against the sealing material 40.
The airtightness inside the pressurized container 21 is maintained by this action. Therefore, when the injection valve 22 is opened, pressurized gas is sent into the pressurized container 21, so that the molten metal in the pressurized container 21 flows into the cavity 37 through the inner hole of the stalk 38 and the molten metal pool 39. be ejected. When the injection of the molten metal into the cavity 37 is finished and the supply of pressurized gas into the pressurized container 21 is stopped,
The molten metal in the upper part of the stalk 38 falls into the pressurized container 21 due to its own weight, but at that time, the molten metal on the stalk 38 side that is above the lower surface of the U-shaped molten metal pool 39 on the stalk 38 side Since all of the molten metal falls into the pressurized container 21, the hot water drains very well here, and no biscuits are formed, making subsequent processing easier.

After waiting for the molten metal in the cavity 37 to solidify, the mold clamping by the mold clamping cylinder 6 is released, and the lifting cylinder 2 is opened.
After raising both molds 30 and 32 and removing the stalk 38 from the pressurized container 21 at step 7, the mold opening/closing unit 24 is moved to the carriage 2.
6 and move it to the outside position shown in the figure. Then, the piston rod 36 of the mold opening/closing cylinder 31 is moved forward to greatly raise the movable mold 32 to open the mold, and the extrusion cylinder 44 is operated to lower the extrusion pin 46 to extrude the product from the cavity 37. Take it out of the machine. After that, the insides of the molds 30 and 32 are cleaned and a release agent is applied, and then the molds are matched to complete one casting cycle.

In the above embodiment, a toggle link type short stroke mold clamping device was used as the mold clamping device in the mold clamping station 10, but this ensures that mold clamping and sealing are performed reliably. This is because it is possible to easily detect whether mold clamping has been reliably performed by stroke detection using a limit switch or the like. In other words, if a direct pressure type mold clamping device is used instead of such a short stroke type mold clamping device, if molten metal solidification or something gets caught between the mold side and the fixed platen 2. To,
Even if the pressure in the mold clamping cylinder 6 rises to a predetermined pressure, mold clamping and sealing may not be performed reliably, but this can be easily detected if a toggle link type mold clamping device is used. .

[0017]

Effects of the Invention As is clear from the above description, a die casting machine according to the present invention includes a mold clamping station equipped with a mold clamping device that clamps a mold by lowering a movable platen with respect to a fixed platen, and A pressurized molten metal container that is attached to the lower surface and opens to the upper surface of the fixed platen that can introduce gas, a pouring device that supplies molten metal to the pressurized molten container, and a trolley that moves between the mold clamping station and the outside of the machine. A mold opening/closing unit equipped with a fixed mold and a movable mold that can be opened and closed, mounted on the trolley so that it can move up and down, and the mold opening/closing unit fixed to the fixed mold and entering the mold clamping station are lowered. By providing a stalk that enters the molten metal pressurizing container and communicating the molten metal pressurizing device and the mold cavity, and a heating device that heats the stalk, it is possible to reduce the pressure during maintenance and inspection of the pressurized container. Since there is no need to attach or detach the container, maintenance and inspection work, etc. are facilitated, and maintenance and inspection of the stalk that is taken out of the mold clamping station is also facilitated, improving workability and operability. Furthermore, there is no risk of explosion, which significantly improves safety, and because there is no risk of explosion, Mg alloy die casting can be operated continuously for long periods of time in a safe state, making it extremely practical. be. In addition, when the mold is clamped by the mold clamping device, the lower surface of the mold is strongly pressed against the upper surface of the fixed platen, creating a gas seal with a large mold clamping force, eliminating the need for a special gas sealing device and eliminating the need for a special gas sealing device. The clamping force can be used as a gas sealing force, and the airtightness inside the pressurized container is reliably and easily maintained, and mold clamping and sealing are performed simultaneously in one operation, improving work efficiency. Further, in the present invention, since it is sufficient to put about one shot of molten metal into the pressurized container, the volume of the pressurized container can be minimized and gas consumption is reduced. Furthermore, since gas sealing is sufficient and the pressurized container can be relatively small, the pressure increase characteristics in the pressurized container during injection become sharp, and more efficient injection can be performed.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a die casting machine.

[Explanation of symbols]

2 Fixed platen 6 Mold clamping cylinder 9 Movable platen 10 Mold clamping station 21 Pressurized container 22 Injection valve 23 Water heater 24 Mold opening/closing unit 26 Trolley 30 Fixed mold 32 Movable mold 36 Mold opening/closing cylinder 37 Cavity 38 Stoke 43 Induction heater

Claims (1)

[Claims] 1. A mold clamping station equipped with a mold clamping device that lowers a movable platen with respect to a fixed platen to clamp the mold, and a mold clamping station that is attached to the lower surface of the fixed platen and capable of introducing gas through an opening to the upper surface of the fixed platen. A pressurized molten metal container, a pouring device that supplies molten metal to the pressurized molten metal container, a trolley that moves between the mold clamping station and the outside of the machine, and a fixed mold mounted on the trolley so as to be able to move up and down. and a mold opening/closing unit having a movable mold that can be opened and closed freely, and a mold opening/closing unit fixed to the fixed mold and entering the mold clamping station, which enters into the molten metal pressurizing container by lowering the mold opening/closing unit, and the molten metal pressurizing device. A die-casting machine comprising: a stalk that communicates with a mold cavity; and a heating device that heats the stalk.