JP4402007B2 - Die casting apparatus and die casting method - Google Patents

Description

  The present invention relates to a die casting apparatus capable of casting a cast product such as an aluminum alloy by filling the mold cavity from below with a molten metal, and in particular, supplying the melt from below into the mold cavity using a gas pressurized hot pot. The present invention relates to a die casting apparatus for filling and a die casting method using the same.

  Conventionally, in a die casting apparatus for casting aluminum alloy or the like in which a molten metal such as a molten aluminum alloy is poured into a mold cavity formed by a fixed mold and a movable mold and cooled to produce a casting, FIG. As shown, when supplying molten metal to the mold cavity, a method is adopted in which the molten metal held in the molten metal holding furnace is drawn by the ladle and poured from the inlet hole at the top of the casting sleeve. The inlet hole was large and had to be a long sleeve. When such a casting sleeve is used, the amount of molten metal poured into the casting sleeve for one batch is significantly smaller than the sum of the volume of the casting sleeve and the hot water pool provided at the tip thereof, and the molten metal poured Without filling the casting sleeve, the molten metal surface is likely to be oxidized due to a large air reservoir at the top of the molten metal, and the contact area with the casting sleeve is also increased and cooled, and a solidified layer is likely to be generated. Also, when the plunger moves forward and fills the mold cavity with the molten metal, the molten metal surface in the casting sleeve undulates, entraining air from the air pool at the top of the molten metal, and the oxide film on the molten metal surface is also mixed, In addition, the generated solidified layer is a resistance to the plunger advance, resulting in a substantial decrease in the casting force, causing defective casting products.

  On the other hand, as means for supplying molten metal from the molten metal holding furnace to the mold cavities while preventing mixing of oxides and gas entrainment, it is already known to use low pressure gas (see Patent Document 1). .) However, such a device contains a large amount of molten metal in a molten metal holding furnace fixed to the main body of the apparatus, and the casting speed is low and the pressure is low. In other words, the apparatus is not sufficiently compatible, and the apparatus has been enlarged. Furthermore, it is not easy to replenish the molten metal in the molten metal holding furnace fixed to the apparatus main body, and it is very difficult to clean and lubricate the inside of the apparatus main body.

The inventor has invented a method using an immersion type electromagnetic pump as means for supplying molten metal to the mold cavity (see Patent Document 2). As the pump becomes larger and the apparatus becomes larger, it is difficult to put it to practical use. In addition, there are problems similar to those described above, such as the difficulty of refilling the melt.
JP 58-55166 A JP 2002-108881 A

  In casting by a die casting apparatus, in order to cast a high-quality cast product, particularly a thin and large-sized cast product, it is necessary to fill the mold cavity with molten metal at a high speed. Also, in order to prevent the inclusion of oxides and gas entrainment that cause defective defects in castings, and to prevent shrinkage caused by solidification shrinkage, it is effective to fill the molten metal from below and use a sufficient amount of molten metal. It is necessary to replenish with pressure. At that time, in order to reduce trouble during operation, it is necessary to simplify the structure of the cavity and the structure of the entire casting apparatus. Work efficiency and ease of maintenance are also very important factors.

  An object of the present invention is to fill a mold cavity with molten metal at high speed, and effectively pressurize the molten metal in the closed cavity, thereby easily casting a cast product without generation of sink marks and without entrainment of gas. Another object of the present invention is to provide a die-casting apparatus that can be operated efficiently and is easy to maintain and has a low equipment cost, and a die-casting method using the die-casting apparatus.

  The present inventors have intensively studied to solve the above-mentioned problems, and by using a gas pressurized pouring pan that can be attached and detached with the apparatus main body, to make a die casting casting apparatus that has high work efficiency and is easy to maintain and has a low equipment cost. It is possible to supply the molten metal at a high speed by increasing the gas pressure of the gas pressurized pouring pan, and it can be found that a cast product can be cast without the inclusion of an oxide film and gas entrainment. The invention has been completed. Furthermore, after the cast molten metal is filled in the cavity, if the molten metal in such a closed state is effectively pressurized by shortening the pressure transmission distance at a plurality of locations, there is no generation of shrinkage and the inclusion of oxide film and gas. The present inventors have found that it is possible to cast a cast product that does not involve winding, and have completed the present invention.

That is, the present invention relates to a fixed mold and a movable mold capable of forming mold cavities, a cast sleeve provided on the fixed mold side and communicating with the mold cavity, and sliding in the cast sleeve to be sent to the cast sleeve. An apparatus main body having a plunger for injecting the molten metal into the mold cavity, and a casting means for supplying and filling the molten metal into the casting sleeve from below through a molten metal delivery opening formed in the casting sleeve. A die-casting apparatus, wherein the casting means is attached to and detached from the apparatus main body, desorbed from the apparatus main body, moves and supplies hot water, and has a gas pressurized pouring pot that can be attached to and detached from the apparatus main body. By installing a die-casting apparatus (Claim 1) and a gas pressurized pouring pan characterized by having a capacity capable of accommodating the molten metal required for one casting. The die-cast casting apparatus (Claim 2) according to claim 1 or a gas pressurized pouring pan provided with cast stalk, wherein an upper end portion of the cast stalk is closely attached to the apparatus main body and sealed. 3. The die-cast casting apparatus according to claim 1 or 2 (Claim 3) or the apparatus main body is provided with cast stalk, and the upper end portion of the gas pressurizing pouring pan is brought into close contact with the apparatus main body and sealed. about the die casting apparatus according to claim 1 or 2, characterized in that to form a structure (claim 4).

The present invention uses a die casting apparatus according to any one of claims 1 to 4, sent to the sleeve pouring the molten metal through the stalk casting from gas pressure injection Yunabe, then a plunger sliding in casting sleeve When the plunger tip of the plunger closes the molten metal delivery opening of the casting sleeve, the front portion of the plunger tip in the casting sleeve is filled with the molten metal, and the plunger is further advanced to move the molten metal to the mold cavity. This is a die-casting method that casts and pressurizes the cast product without gas entrainment, and immediately closes the molten metal delivery opening of the cast sleeve and immediately releases the gas pressure in the gas pressurized molten metal pan to the atmosphere. Detach from the main body of the equipment, supply the required molten metal to the gas pressurization molten metal pan, attach it to the main body of the equipment again, and prepare for the next casting Relates to die casting wherein the Rukoto (claim 5).

  According to the present invention, molten metal is filled into a mold cavity at high speed, and the molten metal in the closed cavity is effectively pressurized to easily cast a cast product that is free from shrinkage and does not involve gas. It is possible to provide a die-casting apparatus that can perform operations, has high work efficiency, is easy to maintain, and has a low equipment cost, and a die-casting method using the die-casting apparatus.

  The die casting apparatus of the present invention includes a fixed mold and a movable mold capable of forming a mold cavity, a cast sleeve provided on the fixed mold side and communicating with the mold cavity, and sliding in the cast sleeve. An apparatus body having a plunger for injecting molten metal delivered to the casting sleeve into the mold cavity, and casting for supplying the molten metal to the casting sleeve from below through a molten metal delivery opening formed in the casting sleeve. And is not particularly limited as long as the casting means has a gas pressurized pouring pan that can be attached to and detached from the apparatus main body. In the die casting apparatus of the invention, since the pouring pot is small and the gas pressure can be increased, a high casting speed can be secured, thin wall casting becomes possible, and the pouring pot can be moved. As a result, it is easy to refill the molten metal and not only the equipment cost is reduced, but also the arrangement and operation of the device are facilitated, and when the mold is opened, the pouring pan is taken out of the machine to clean the casting sleeve and the mold. Spraying work for surface cooling and lubrication can be done easily and safely. The cast product that can be produced by the die casting apparatus of the present invention is not particularly limited, but a light metal alloy, particularly an aluminum alloy having a large solidification shrinkage is preferable. Since aluminum shrinks by about 7% when solidified, the casting apparatus and casting method of the present invention, which can prevent the formation of shrinkage nests, are particularly thin and large-sized from molten metal made of light metal alloy such as aluminum alloy that has large solidification shrinkage. The present invention can be applied particularly advantageously when casting a cast product.

  The gas pressurizing pouring pot in the casting means is not particularly limited as long as it is a pouring pan capable of gas pressurization and can be attached to and detached from the apparatus main body. The gas pressurized hot water pot needs to have a sealed structure, but for example, a gas pressurized hot water pot with an open top can be provided with a lid, but the sealed structure can be formed by attaching it to the device body. It is preferable to do. As a configuration for forming a sealed structure by mounting on the apparatus main body, when the gas pressurized pouring pan has a cast stalk, the upper end of the cast stalk can be brought into close contact with the apparatus main body to form a sealed structure. Specifically, for example, the upper surface of the stalk can be pressed against the lower portion of the casting sleeve to form a sealed structure. In addition, when the apparatus main body is equipped with cast stalk, the upper end of the gas pressurized pouring pan can be brought into close contact with the apparatus main body to form a sealed structure. It can be pressed against the lower surface of the fixed plate to form a sealed structure, or can be pushed into a seal mold provided at the lower part of the fixed mold or fixed plate to form the closed structure. At this time, it is preferable to make the upper part of the gas pressurized hot water pot smaller than the lower part and to make it easy to seal the apparatus main body.

  In this way, by using a gas pressurized pouring pan that can be attached to and detached from the apparatus main body, the molten metal can be introduced from, for example, a hot water ladle from above (opened) the gas pressurized pouring pan that has been detached (removed). The molten metal can be replenished very easily. Further, since the gas pressurized hot pot can be detached and the spraying operation for cleaning and lubrication of the casting sleeve of the apparatus main body can be performed, maintenance is very easy.

  The gas pressurized hot water pouring pan may be provided with a molten metal supply pipe (a molten metal supply passage) communicated with an opening provided at a lower portion thereof. An openable and closable hot water supply lid with a durable sealing force is provided. Here, the lower part of the gas pressurized hot water pot provided with an opening means a part below the molten metal surface in the molten metal pot (when full), and is preferably a part below the lower end of the casting stalk. In this case, it is not always necessary to remove and move the gas pressurized molten metal pan during hot water supply, but when removing and supplying hot water, the moving distance can be shortened and the work can be performed more efficiently.

  Such a pressurized gas pouring pan is preferably provided with a heating means, whereby it is possible to suppress the generation of a solidified layer and to suppress the occurrence of defects in the cast product as much as possible due to good hot water circulation.

  Moreover, as a capacity | capacitance of a gas pressurization pouring pot, it is a capacity | capacitance which can accommodate the molten metal required, for example for 1-3 times of casting from the point of prevention of the enlargement of an apparatus and the ease of conveyance of a gas pressurization pouring pot. It is more preferable that the capacity is enough to accommodate the molten metal required for one casting. By making the capacity to accommodate the molten metal required for one casting, the amount of molten metal in the pouring pan at the time of each casting is always constant, so there is no need for pressure correction, and continuous filling is performed more simply. In addition, it is possible to suppress the mixing of oxides and entrainment of gas and to perform stable operation. That is, in the case of the capacity for multiple times, the liquid level at the time of each casting is different, and it is necessary to finely adjust the pressure, but by making the capacity that can accommodate the molten metal required for one casting There is no need to make such subtle adjustments.

  The downsizing of such a pressurized gas pouring pan enables the molten metal to be raised and the volume of the gas part to be reduced, so that the supply amount of the molten metal can be easily adjusted and the gas pressure can be increased. It is possible to supply a molten metal quantitatively to the cavity, increase the supply speed, and shorten the shot time lag, enabling high-quality casting and casting of a thin and large-sized cast product. Furthermore, by using such a pouring pan, the production cycle time is shortened, so that the productivity is improved.

  Further, the casting means preferably has a vacuum suction mechanism that, in addition to the gas pressurized hot pot, sucks the gas in the mold cavity by vacuum and fills the molten metal in the gas pressurized hot pot with vacuum. As a result, the mold cavity can be filled with the molten metal at a high speed, and the gas in the mold cavity can be discharged to prevent the gas from being entrained. This vacuum suction can be performed through a gas discharge passage which will be described later.

  As the casting sleeve, for example, the molten metal in the casting sleeve can be poured into the mold cavity, for example, through a stationary plate for fixing a stationary mold made of alloy steel, or in a substantially horizontal state or substantially in the stationary mold. Examples can be exemplified by those fixed in a vertical state or in an inclined state (hereinafter, a hot water supply device in which the casting sleeve is installed in a substantially horizontal state is a horizontal type hot water supply device, and the casting sleeve is installed in a substantially vertical state. The hot water supply device is called a vertical type hot water supply device). The casting sleeve is provided with a molten metal delivery opening which is a communication port with Stoke.For example, in a horizontal type hot water supply apparatus, a molten metal delivery opening is provided on the side of the casting sleeve on the lower surface of the casting sleeve. In any case, it is possible to provide a molten metal delivery opening in the vicinity of the tip of the casting sleeve closer to the mold cavity, or to provide a molten metal delivery opening on the fixed mold side fixed by the stationary platen. When the plunger tip of the plug closes the molten metal delivery opening in the casting sleeve, the inner volume of the plunger tip front portion and the hot water reservoir in the casting sleeve is reduced, and casting is performed with the amount of pouring required for one casting. As a result of at least the front part of the plunger tip in the sleeve being filled with molten metal, the contact between the molten metal and gas is reduced as much as possible. The is advanced Yachippu, when injecting the molten metal from the side gate into the cavity product portion, molten metal or ruffled preferable in that there is no fear that involve gas. For example, in the case of a horizontal type hot water supply device, when the plunger tip in the casting sleeve closes the molten metal delivery opening, the volume in front of the plunger tip in the casting sleeve and the inner volume below the highest horizontal plane of the hot water sleeve Is configured to be smaller than the amount of pouring required for one casting, the plunger tip front portion in the casting sleeve can be filled with at least the molten metal.

  Further, as a plunger in the hot water supply device for injecting the molten metal delivered to the casting sleeve into the mold cavity, a plunger tip (plunger head) capable of sliding in the casting sleeve in an airtight manner and the plunger Examples include a plunger rod that can move the tip back and forth, and examples of the drive source for the reciprocating movement of the plunger rod include a hydraulic cylinder and a servo motor. When the plunger tip is positioned at the retreat limit of the casting sleeve, it is preferable that the casting sleeve near the mold cavity side of the plunger tip is provided with a molten metal delivery opening from the stalk because pouring can be performed quickly. In addition, normally, the length is such that the molten metal delivery opening from the stalk is closed even when the plunger tip is positioned at the advance limit of the casting sleeve so that the molten metal does not flow out to the back surface of the plunger tip. It is preferable to use the plunger tip in order to avoid driving trouble.

  In addition, when the plunger tip is positioned at the forward limit of the casting sleeve, a plunger tip having such a length as to open the molten metal delivery opening from the stalk can be used. It is preferable that a large-diameter sliding portion that slides in the casting sleeve is provided, and a gas chamber be formed between the large-diameter sliding portion and the plunger tip of the plunger rod. That is, a gas chamber is formed between the plunger tip positioned at the front and the large-diameter sliding portion positioned at the rear, and gas is fed into the gas chamber using a gas supply means, and the rear end of the plunger tip It is also possible to connect the gas chamber and the stalk by reaching the molten metal delivery opening, and to drop the molten metal in the stalk into the pouring pan by the gas pressure from the gas chamber. As a result, it is possible to reliably guide all molten metal to the molten metal pan without leaving the molten metal in the stalk, and troubles such as squeezing of the molten metal when the plunger tip is retracted and solidification in the stalk are generated. Can be prevented. Although it does not restrict | limit especially as a gas pressure in the said gas chamber, It is preferable that it is equivalent to a molten metal pouring pressure, and the same gas supply means as the gas supply means which supplies the gas sent in to a pouring pan can be used. The rear part of the plunger rod provided with the large-diameter sliding part may be a position having a certain distance from the plunger tip so that a gas chamber having a predetermined capacity can be formed. The central part and the rear end part of the jar rod can be mentioned, and the large-diameter sliding part may be integrally molded with the plunger rod, or may be attached separately, like the plunger tip.

  In addition to the plunger, it is preferable that a pressurizing means for pressurizing the molten metal injected into the mold cavity is provided in a hot water reservoir for pressurizing means such as a cavity product part of the mold cavity. As a pressurizing means for pressurizing the molten metal injected into the mold cavity, a means capable of suppressing the generation of the shrinkage nest during solidification by pressurizing the molten metal filled in the closed mold cavity. Any means can be used, but as a means for pressurizing the molten metal in the mold cavity, a pressurizing pin slidably disposed on the movable mold forming the cavity product part of the mold cavity is concretely used. Can be exemplified. When the molten metal in the mold cavity is solidified, the pressure pin can be advanced into the mold cavity to pressurize the molten metal to replenish the solidified shrinkage volume and prevent the formation of sinkholes. By adjusting the pressurization speed, such as by controlling the advancement speed of the pressurization pin to match the solidification shrinkage speed of the melt in the cavity product part, burrs can be blown with a press device with a small clamping force. It is possible to prevent the formation of a sink nest while preventing Also, a plurality of pressure pins can be provided.

  The mold cavity is preferably a mold cavity capable of casting a thin and large casting, and gradually expands from the end of the casting sleeve to the adjacent mold cavity inlet in communication with the casting sleeve. Since the plunger does not pressurize the solidified layer generated on the side wall of the reservoir, the resistance when the plunger moves forward is reduced and the applied pressure is small. It is more preferable in that the molten metal can be sufficiently pressurized. The hot water reservoir can be communicated with the mold cavity via the side gate.

  In addition, the cast stalk may be provided in the apparatus main body or in the gas pressurized molten metal pan, but the molten metal in the gas pressurized molten metal pan is lower than the molten metal surface, It is preferable that the lower end is located below. Thereby, it becomes possible to suppress the defect of the casting product due to mixing of the solidified layer and the oxide film without mixing the oxide film into the molten metal.

  The die casting apparatus of the present invention has a gas discharge passage capable of discharging the gas existing in the cavity when the molten metal is filled into the mold cavity, and a gap for the molten metal solidification zone communicated with the gas discharge passage. Is preferred. The gas discharge passage is preferably configured by a gas discharge hole penetrating through the movable mold and a gas discharge gap. The molten metal solidification zone gap is preferably provided in the vicinity of the gas discharge passage, and particularly preferably close to the pressurizing means. As the gap for the molten metal solidification zone, for example, after discharging the gas in the cavity from the gas discharge passage, the molten metal can be solidified in the gap that becomes the molten metal solidification zone. Any air gap can be used as long as it can seal and close the inside of the cavity, and simply by providing such a gap for the molten metal solidification zone, an air vent valve, a filter, etc. are provided and a complicated switching valve or The inside of the cavities can be easily sealed and closed without using a valve, and complicated operations such as pressure adjustment are not required when the casting machine is in operation. It can be said that providing a void is extremely practical.

  Specifically, the molten metal solidification zone gap includes a molten metal solidification zone communicating with a gas discharge passage through a gas discharge gap formed between the outer peripheral surface of the pressure pin and the inner peripheral surface of the movable mold. An example of such a molten metal solidification zone gap is provided concentrically with the pressure pin, and has an inner diameter that is 1 to 5 mm larger than the diameter of the pressure pin and a depth (length) of about 10 to 40 mm. ) Can be specifically exemplified. In this way, the outer diameter of each reservoir is slightly larger than the outer shape of the pressure pin, so that the solidified layer formed on the outer peripheral wall of each reservoir is brought into the product by the pressure pin. While being pushed in, the pressurization resistance of a pressurization pin can be decreased. As described above, when the gap for the molten metal solidification zone is designed to have a size that matches the temperature of the molten metal and the casting speed, the hot water is cooled and solidified in the gap when the molten metal is filled. Never invade.

  Further, the gas discharge gap preferably has a structure or size that does not allow the hot water to flow in. For example, the gas discharge gap is provided concentrically with the pressure pin, and 0.4 to 1. A gas discharge gap having an inner diameter that is about 0 mm larger can be specifically mentioned. When the mold cavity is evacuated, in order to prevent intrusion of air, the parting surface is not provided with gas discharge holes and gas discharge passages. A gas exhaust groove connected to the gas exhaust port is provided to prevent air from leaking into the mold cavity from outside the mold.

  By the way, when the casting start speed of the molten metal by the combined use of the gas pressure by the gas pressurized pouring pan and the vacuum suction mechanism is set to an optimum value of 1.0 to 2.4 m / sec, the molten metal solidified provided close to the outer periphery of the pressure pin. The air resistance in the two-stage gaps such as the zone gap and the gas discharge gap is increased, but the purpose of installing the molten metal solidification zone gap and the gas discharge gap by appropriately selecting the number and arrangement of the pressure pins. Can be achieved. That is, those skilled in the art can easily design a structure in which the hot water is cooled and solidified in the melt solidification zone gap having a two-stage gap and does not enter the gas discharge gap narrower than the melt solidification zone gap. Further, in order to cool and solidify the hot water in the molten metal solidification zone gap, a material having good heat conductivity such as beryllium copper can be used for the pressure pin, and the inside thereof can be cooled with water.

  Next, the die casting method of the present invention will be described.

The die-casting method of the present invention is a casting method using the above-mentioned die-casting apparatus, wherein the molten metal is sent from the gas pressurized pouring pot to the casting sleeve through the casting stalk, and then the plunger sliding in the casting sleeve is advanced. When the plunger tip of the plunger closes the molten metal delivery opening in the casting sleeve, the front portion of the plunger tip in the casting sleeve is filled with the molten metal, and the plunger is further moved forward to move the molten metal into the mold cavity. There is no particular limitation as long as it is a die-casting method that casts and pressurizes the cast product without gas entrainment. For example, the upper end of the gas pressurizing pouring pan that has received a molten metal of one or more times of pouring is used. Push in the seal packing provided at the bottom of the fixed plate, seal the seal, and fill the hot pot with 1 kg / c. ^Two or more gas pressure was added, and sends the molten metal in the casting sleeve through Note pressurized casting stalk the molten metal surface of the hot water in the pot. At this time, when the gas pressurized pouring pan has a molten metal supply pipe, the same gas pressure may be simultaneously applied from above the hot water surface of the supply pipe. Next, the plunger sliding inside the casting sleeve is advanced, and when the plunger tip of the plunger closes the molten metal delivery opening in the casting sleeve, the plunger tip front portion in the casting sleeve is filled with the molten metal, Furthermore, the plunger is advanced, the molten metal is injected and pressurized into the mold cavity, and then the molten metal in the mold cavity is pressurized with a pressurizing means (pressurizing pin), so that no shrinkage occurs during solidification, and A casting without gas entrainment, preferably a light metal alloy thin and large casting is cast.

  Further, in the die casting method of the present invention, after closing the molten metal delivery opening of the casting sleeve, the gas pressure in the gas pressurized molten metal pan is immediately released to the atmosphere and detached from the apparatus main body, so that the necessary molten metal for the next time is supplied. It is preferable to prepare for the next casting by supplying and attaching to the apparatus main body again. Thereby, it can cast very efficiently using one gas pressurization pouring pot. It is also possible to cast using a plurality of gas pressurized hot pots. In addition, when using a gas pressurized pouring pan equipped with a molten metal supply pipe, the gas in the pouring pan is released to the atmosphere, and the molten metal supply pipe is covered with or without detaching the molten metal pot from the apparatus body. Open and supply the next molten metal.

  When using the die casting apparatus of the present invention in which a large-diameter sliding part is provided at the rear part of the plunger rod, the plunger sliding inside the casting sleeve is advanced, and the plunger rod of the plunger When a large-diameter sliding part of the plunger is inserted into the casting sleeve, a gas chamber is formed around the plunger rod small-diameter part between the plunger tip and the large-diameter sliding part, and the gas is sent to the gas chamber. The plunger is advanced further, the rear end of the large-diameter storage part reaches the molten metal delivery opening, the gas chamber and stalk are connected, and the molten metal in the stalk falls to the pouring pan with the gas pressure from the gas chamber. It can also be made. As a result, it is possible to reliably guide all molten metal to the molten metal pan without leaving the molten metal in the stalk, and troubles such as squeezing of the molten metal when the plunger tip is retracted and solidification in the stalk are generated. Can be prevented.

  Preferred embodiments to which the die casting apparatus of the present invention is applied will be described below with reference to the drawings, but the technical scope of the present invention is not limited to these embodiments.

  1 is a schematic cross-sectional view showing a die casting apparatus of the present invention, FIG. 2 is a view taken along the line AA in FIG. 1, and FIGS. 3 to 8 show operating states of the die casting apparatus of the present invention shown in FIG. It is explanatory drawing shown. Hereinafter, a die casting apparatus equipped with a gas pressurized hot pot and a vacuum suction mechanism as casting means will be described as an example.

  The die casting apparatus of the present invention shown in FIGS. 1 to 8 is a fixed mold 1 made of alloy steel fixed to a fixed platen 3 arranged on the right side in the drawing, and a drawing on which the fixed mold 1 is pressure-bonded. The movable sleeve 2 disposed on the left side and the casting sleeve 5 for injecting molten metal into the mold cavity C formed between the stationary mold 1 and the movable mold 2 reciprocate in the casting sleeve 5. A plunger 6, a gas pressure pouring pot 7 that can be attached and detached to supply molten metal to the casting sleeve 5 via the stalk 9, a pressure pin 11 that pressurizes the molten metal in the mold cavity C, and a mold cavity A vacuum suction passage 13 communicating with C is provided, and a molten metal is automatically cast into the mold cavity C and cooled to manufacture a cast product. Although not shown in the drawing, the die casting apparatus is provided with a mold clamping apparatus for performing mold opening for taking out the cast product 10 from the mold cavity C after cooling the molten metal.

  As shown in FIG. 1, the casting sleeve 5 passes through the fixed plate 3 so as to communicate with the mold cavity C, is fixed substantially horizontally to the fixed mold 1, and supplies the molten metal M to the mold cavity C. A molten metal delivery opening 51 to which a stalk (communication duct) 9 inserted into the gas pressurizing pouring pan 7 is connected is provided on the lower surface of the tube wall near the tip near the mold cavity. Further, the inner diameter of the casting sleeve 5 increases the degree of fullness of the molten metal to reduce the volume of the space to eliminate gas entrainment, and the plunger 6 that slides in an airtight manner on the inner wall of the casting sleeve 5. In order to reduce the working surface and obtain the same casting pressure with a small driving force, the diameter is smaller than that of the conventional one, and the plunger tip 63 of the plunger 6 closes the molten metal delivery opening 51 in the casting sleeve 5. At this time, the front portion of the plunger tip 63 in the casting sleeve 5 is configured to be filled with at least the molten metal. That is, when the plunger tip 63 in the casting sleeve 5 closes the molten metal delivery opening 51, the volume in front of the plunger tip 63 in the casting sleeve 5 and the horizontal surface below the highest position of the casting sleeve 5 of the hot water reservoir C1. In order to make the total internal volume smaller than the amount of pouring required for one casting, the length of the casting sleeve 5 is short and has a small diameter.

  The plunger 6 reciprocating in the casting sleeve 5 pushes out the molten metal M supplied to the casting sleeve 5 to the mold cavity C, and is driven by a hydraulic cylinder 61, and has a small-diameter plunger rod 62 and A plunger tip 63 which is provided at the distal end of the plunger rod 62 and has substantially the same diameter as the inner diameter of the casting sleeve 5 which slides on the inner wall of the casting sleeve 5, and whose distal end surface constitutes a working surface for pushing out the molten metal M; Have The length of the plunger tip 63 in the axial direction closes the molten metal delivery opening 51 even in the advance limit, and closes the molten metal delivery opening 51 provided on the lower surface of the pipe wall of the casting sleeve 5 when arranged in the backward limit. The entire length of the molten metal delivery opening 51 is opened while the molten metal M is delivered from the gas pressurizing pouring pan 7 to the casting sleeve 5. Then, the supply of the molten metal M to the casting sleeve 5 is completed and moved forward, so that the molten metal M supplied to the casting sleeve 5 is pushed forward while the molten metal delivery opening 51 is closed. The supply of surplus molten metal M to the casting sleeve 5 can be prevented.

  The gas pressurizing pouring pan 7 is a pressure pouring pan capable of accommodating the molten metal necessary for one casting, and is connected to the casting sleeve 5 through the stalk 9 and holds the molten metal M supplied to the casting sleeve 5. . In addition, a pressurized gas passage 81 communicates with the gas pressurized hot water pouring pan 7 so that the gas pressurized hot pouring pan 7 can be pressurized. When the gas pressurized pouring pan 7 is attached to the main body of the apparatus and sealed with the packing 8, the gas volume at the top of the gas pressurized pouring pan 7 is small and the pouring speed can be easily controlled by the gas pressure. And when it is moved down to a position not hitting the lower end of the stalk 9 and moved, the upper part of the gas pressurizing pouring pan 7 is released, and a structure that can easily replenish the molten metal M by any method such as a molten metal pump or a ladle. It has become. Further, when the apparatus main body is mounted, the lower end inlet of the stalk 9 is disposed below the lower limit position of the molten metal surface that is lowered by one pouring of the mold cavity, and when the molten metal M is delivered, No oxide film or the like in the vicinity of the surface is mixed into the casting sleeve. The stalk 9 is made of ceramic, reduces adhesion of the molten metal M, and prevents erosion by the molten metal M.

  The mold cavity C communicating with the casting sleeve 5 is provided with a tapered reservoir C1 that is slightly larger than the inner diameter of the casting sleeve 5, and the reservoir C1 is a product portion of the mold cavity C via the side gate C2. Communicating with Further, a pressure pin 11 is provided at one end of the product portion of the mold cavity C to advance the molten metal in the mold cavity C to the pressure pin reservoir 14 by driving the pressure pin hydraulic cylinder 12. It has been. Although not shown, a melt solidification zone gap communicating with the vacuum suction passage (gas discharge passage) 13 is provided in the vicinity of the pressurizing means.

  Next, a die casting method using the above die casting apparatus will be described.

  From the initial state shown in FIG. 3, the gas pressure applied to the molten metal surface of the pressurized gas fed into the gas pressurized hot water pouring pan 7 through the pressurized gas inlet 81 (see FIG. 1) communicated with the vacuum suction passage 13. By the suction by the vacuum suction mechanism, a molten metal having a required amount for one casting is sent from the gas pressurized hot pot 7 into the casting sleeve 5. At this time, as shown in FIG. 4, the molten metal surface that has entered the hot water reservoir C <b> 1 of the mold cavity C from the casting sleeve 5 is higher than the highest horizontal surface of the casting sleeve 5, and the plunger tip in the casting sleeve 5. Since the front part of 63 is filled with the molten metal, no air remains in the casting sleeve 5 and the surface of the molten metal does not oxidize. When the delivery of the molten metal is completed, as shown in FIG. 5, the hydraulic valve 61 is opened and the hydraulic cylinder 61 is operated, and the forward movement of the plunger tip 63 is started via the plunger rod 62. The delivery opening 51 is closed, and the mold cavity C is filled with molten metal. As described above, since no air remains in the casting sleeve 5, when the plunger tip 63 is advanced and the molten metal is filled into the mold cavity C (cavity product part), the molten metal surface is not ruffled, There is no entrainment of gas or oxide film. Further, since the inner diameter of the hot water reservoir C1 of the mold cavity C is designed to be larger than the inner diameter of the casting sleeve 5, if a solidified layer is generated in the hot water reservoir C1 of the mold cavity C. However, the plunger 6 is not pushed into the mold cavity C.

  When filling is completed and cooling of the molten metal is started, solidification shrinkage of the molten metal occurs. Therefore, as shown in FIG. 6, the pressure pin 11 is operated by the pressure pin hydraulic cylinder 12 under pressure by the plunger. Although it is difficult to transmit pressure to the end of the mold cavity C only by pressurization with the plunger 6, by operating the pressurization pin 11 to pressurize, a dense tissue free from shrinkage due to coagulation shrinkage is obtained. A cast product can be obtained. After the cooling and solidification of the molten metal in the mold cavity C is completed, the mold is opened (FIG. 7). The product material taken out by the movable mold can be pushed out by each pressure pin and extrusion pin (FIG. 8). .

9 and 10 are explanatory views of a die casting apparatus according to another embodiment of the present invention. FIG. 9 shows a state in which the molten metal is supplied into the casting sleeve, and FIG. 10 shows the molten metal in the mold cavity. The state where filling is completed is shown.
As shown in FIGS. 9 and 10, the die casting apparatus according to another embodiment of the present invention is of a type in which the molten metal in the stalk is immediately dropped into the pouring pan after the completion of casting, and after the plunger rod. When the end portion 64 (large diameter sliding portion 64) has the same diameter as the outer diameter of the plunger tip 63 and is inserted into the casting sleeve 5, a gas chamber 52 is formed and a gas supply means is used to enter the gas chamber. Gas is introduced from 82. That is, as shown in FIG. 9, in the initial stage when filling molten metal, no gas is supplied to the gas chamber 52 and the rear of the plunger tip 63 is also opened, but by moving the plunger forward by a predetermined distance, A sealed gas chamber 52 is formed, and gas having the same pressure as that in the pouring pan 7 is supplied into the gas chamber 52 using a gas supply means. As shown in FIG. 10, when the plunger tip 63 moves forward in the casting sleeve and the rear end thereof reaches the molten metal delivery opening 51, the gas chamber 52 is connected to the stalk 9, and the gas in the gas chamber 52 flows into the molten metal delivery opening 51. Since the gas pressure is the same as that of the gas pressurized pouring pan 7 at this time, the (residual) molten metal surface in the stalk 9 immediately falls to the molten metal surface in the gas pressurized pouring pan 7. In addition, the gas inside the gas pressurizing and pouring pan 7 and the gas chamber 52 can be immediately released to the atmosphere, the gas pressurizing and pouring pan 7 can be safely detached, and the molten metal can be squeezed or stalked when the plunger tip 63 is retracted. It is possible to prevent the occurrence of troubles such as solidification and fixing inside.

FIG. 11 is an explanatory view of a die casting apparatus according to still another embodiment of the present invention.
As shown in FIG. 11, in the die casting apparatus of the present invention, the gas pressurized pouring pan 7 includes a molten metal supply pipe 21 communicating with an opening provided in a lower portion thereof, and a hot water supply port 22 of the molten metal supply pipe 21 has a An openable and closable hot water supply lid 25 having a sealing force capable of withstanding gas pressurization is provided. The hot water supply sleeve 21 provided at the upper part of the molten metal supply pipe 21 in such a die casting apparatus is provided with a gas outlet 24 and a pressurized gas inlet 81 above the pressurized gas pouring pan 7 at the time of gas pressurization. The pressurized gas is supplied from the gas outlet and the same pressurized gas is supplied also from the gas outlet 24, so that the molten metal can be supplied and filled more efficiently. Then, after casting, the molten metal can be dropped immediately by introducing the gas from the gas chamber 52 into the stalk 9 as described above. However, together with or alone, the hot water supply port 22 of the molten metal supply pipe 21 is used. The vacuum gas is sucked from the gas outlet 24, the molten metal surface in the molten metal supply pipe 21 is pulled up, the molten metal surface in the molten metal pan 7 is pulled down to the lower end of the stalk 9, and the molten metal in the stalk 9 is dropped earlier. You can also.

It is a schematic longitudinal cross-sectional view of the die-casting apparatus of this invention. It is an AA arrow line view in FIG. It is explanatory drawing which shows the operation state of the die-casting apparatus of this invention shown in FIG. 1, and shows the state before casting. It is explanatory drawing which shows the operation state of the die-casting apparatus of this invention shown in FIG. 1, and the state which supplied the molten metal in the casting sleeve is shown. It is explanatory drawing which shows the operation state of the die-casting apparatus of this invention shown in FIG. 1, and the state which filled the metal mold cavity with the molten metal is shown. It is explanatory drawing which shows the operation state of the die-casting apparatus of this invention shown in FIG. 1, and shows the state by which the molten metal in a metal mold cavity was pressurized. It is explanatory drawing which shows the operation state of the die-casting apparatus of this invention shown in FIG. 1, and shows the state which the filling cooling of the molten metal was completed and the type | mold opened. It is explanatory drawing which shows the operation state of the die-casting apparatus of this invention shown in FIG. 1, and shows the state which takes out a product. It is a figure which shows the operation state of the die-casting apparatus concerning other embodiment of this invention, and shows the state which supplied the molten metal in the casting sleeve. It is a figure which shows the operation state of the die-casting apparatus of this invention shown in FIG. 9, and the state which filled the molten metal in the mold cavity is shown. It is a schematic longitudinal cross-sectional view of the die-casting apparatus concerning other embodiment of this invention. It is a schematic longitudinal cross-sectional view of the conventional common die-casting apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fixed mold 2 ... Movable mold 3 ... Fixed platen 4 ... Movable platen 5 ... Casting sleeve 51 ... Molten metal delivery opening 52 ... Gas chamber 6 ... Plunger 61 ... Hydraulic pressure for plungers Cylinder 62 ... Plunger rod (small diameter part)
63 …… Plunger tip 64 …… Large-diameter sliding part 7 …… Gas pressurized hot water pot 8 …… Packing 81 …… Pressurized gas inlet 82 …… Gas chamber inlet 9 …… Stoke 10 …… Cast 11… Pressurizing pin 12 ... Pressurizing pin hydraulic cylinder 13 ... Vacuum suction passage 14 ... Pressurizing pin hot water reservoir 21 ... Molten supply passage 22 ... Hot water supply port 23 ... Hot water supply sleeve 24 ... Gas outlet port 25 …… Hot water supply lid 26 …… Heating means C ...... Mold cavity C1 …… Hot water reservoir C2 …… Side gate M …… Molten metal

Claims (5)

A fixed mold and a movable mold capable of forming a mold cavity, a cast sleeve provided on the fixed mold side and communicating with the mold cavity, and a molten metal that slides in the cast sleeve and is sent to the cast sleeve A die casting apparatus comprising a device main body having a plunger for injecting into a mold cavity, and casting means for supplying and filling molten metal into the casting sleeve from below through a molten metal delivery opening formed in the casting sleeve. The casting means has a gas pressurized pouring pot that can be attached to and detached from the apparatus main body, which is attached to and detached from the apparatus main body to move and supply hot water, and the capacity of the gas pressurized pouring pot can be cast once. A die casting apparatus characterized by having a capacity capable of accommodating a necessary molten metal.   2. The die casting apparatus according to claim 1, wherein the gas pressure pouring pan is attached to the apparatus body to form a sealed structure.   The die-casting apparatus according to claim 1 or 2, wherein the gas pressurized pouring pan is provided with cast stalk, and an upper end portion of the cast stalk is brought into close contact with the apparatus main body to form a sealed structure.   The die casting apparatus according to claim 1 or 2, wherein the apparatus main body is provided with cast stalk, and an upper end portion of the gas pressurizing pouring pan is brought into close contact with the apparatus main body to form a sealed structure. The die casting apparatus according to any one of claims 1 to 4, wherein the molten metal is sent from the gas pressurized pouring pan to the casting sleeve through the casting stalk, and then the plunger sliding in the casting sleeve is advanced, and the plan When the plunger tip of the jar closes the molten metal delivery opening of the casting sleeve, the plunger tip front part in the casting sleeve is filled with the molten metal, and the plunger is further advanced to inject and press the molten metal into the mold cavity. , A die casting method for casting a casting without gas entrainment,
Immediately after closing the molten metal delivery opening of the casting sleeve, the gas pressure in the gas pressurized molten metal pan is released to the atmosphere and detached from the main body of the apparatus, and the next time the necessary molten metal is supplied to the gas pressurized molten metal pan, and the device is again A die-casting method characterized by being mounted on a main body and preparing for the next casting.