JP2012245525A - Die casting device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die-casting device which can simply produce a cast product having no shrinkage cavity and no gas entrainment by filling a die cavity with molten metal having no contamination with oxide film in a short time, and effectively pressurizing the molten metal in the closed cavity, and which is compact, has high working efficiency, is easy in maintenance and is low in installation cost.SOLUTION: The die-casting device comprises: a fixed die 1 and movable die 2; a casting sleeve 5 which is formed to the fixed die 1 and communicates with a die cavity C through an outlet gate C2; a casting unit which is equipped with a gas-pressurized molten metal-pouring ladle 7, and feeds below, the molten metal having no contamination with oxide film inside the die cavity passing through a casting stalk 9 via a molten metal delivery opening 51 formed on the casting sleeve 5; a casting plunger 6 which slides in the sleeve 5, clogs the opening 51 and pressurizes the molten metal; and a molten metal-feeding furnace 26. The ladle 7 is arranged at a position where the ladle is immersed into the molten metal in the furnace 26, and a closed structure is formed by closing a molten metal inflow port 7a.

Description

  The present invention is a die-casting apparatus capable of casting a cast product such as a light metal alloy from the lower side to supply and fill molten metal into the mold cavity, and in particular, from the lower side, the molten metal is injected into the mold cavity using a gas pressurized hot water pot. The present invention relates to a die casting apparatus for supplying and filling, and a die casting method using the same.

  Conventionally, when casting cast products such as aluminum alloys, especially parts that require strength, it is generally difficult to prevent gas entrainment and oxide film mixing during casting of the molten metal. Die casting equipment cannot be used, and special vertical die casting equipment, gravity casting machines, and low pressure casting machines are used. On the other hand, the present inventors have proposed the die-casting apparatus using the casting means which has a pressurized gas pouring pan, and the method using such an apparatus (for example, refer patent document 1).

JP 2006-116598 A

  In casting with a die casting apparatus, in order to cast a high-quality cast product, especially a large cast product that is thin and requires strength, while preventing the oxide film from mixing, the molten metal does not stagnate halfway, It is necessary to fill the mold cavities within a short time. Moreover, in order to prevent the inclusion of oxide film and gas entrainment, which is a major cause of defective defects in the strength of cast products, and to prevent shrinkage caused by solidification shrinkage, the molten metal is filled from below and solidified. It is necessary to effectively pressurize a sufficient amount of molten metal to replenish the contraction volume. 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 important factors. The die casting apparatus described in the above-mentioned document 1 proposed by the present inventor almost fulfills these requirements, but the present inventor conducted further research.

  The object of the present invention is to fill the mold cavities at high speed within a short period of time, with the molten metal free of oxide film mixed in at a high temperature, effectively pressurize the molten metal in the closed cavities, It is an object of the present invention to provide a die casting casting method that can easily cast a cast product that does not generate a nest and does not involve gas, has high work efficiency, is easy to maintain, and has low equipment costs.

  As a result of diligent research to solve the above-mentioned problems, the present inventor has immersed a gas pressurized pouring pan having a top sealed with a lid and a molten metal inlet at the bottom into the molten metal in the hot water furnace, thereby forming an oxide film on the molten metal surface. By adding the inert gas gas pressure that is not oxidized and pouring the hot water, the work efficiency is good, the maintenance is easy, and the equipment cost is low. In addition, it is possible to supply the molten metal at high speed in a short time by completely increasing the gas pressure of the gas pressurized hot water pan, and to completely fill it, and there is no oxide film mixing and gas entrainment. As a result, the present invention has been completed. In addition, after the cast molten metal fills the cavity, the cast plunger performs additional push-in, and if necessary, the molten metal in the closed state can be effectively shortened by multiple pressure pins. It has been found that when a pressure is applied to the casting, a cast product can be produced in which no shrinkage is generated and no oxide film is mixed and no gas is involved, and the present invention has been completed.

That is, the present invention is (1) a fixed mold and a movable mold that form a mold cavity, a cast sleeve that is provided in the fixed mold and communicates with the mold cavity, and is formed in the cast sleeve. Through the molten metal delivery opening, through the casting stalk, the molten metal is supplied and filled into the mold cavity from below, the casting means equipped with a gas pressurized pouring pan, the inside of the casting sleeve slides, and the molten metal delivery opening A die casting apparatus comprising a casting plunger that pressurizes the molten metal and a hot water furnace, wherein a gas pressurized hot water pan is disposed so as to be immersed in the molten metal in the hot water furnace. The hot water pan has a molten metal inlet at the bottom and a closing member capable of closing the molten metal inlet. The die casting is configured to close the molten metal inlet with the closing member to form a sealed structure. Casting equipment and (2) The gas pressurized hot water pouring pan is provided with cast stalk that protrudes obliquely upward from the side of the pan main body, and is configured to be attached to and detached from the apparatus main body together with or separately from the hot water furnace. (1) or (1) or (3), wherein the capacity of the die-casting apparatus according to (1) above, or (3) the capacity of the gas pressurized pouring pan is a capacity capable of accommodating the molten metal required for one casting. (2) The die-casting apparatus according to any one of (1) to (3), wherein the die-casting apparatus according to (2), or (4) a hot-water level detecting rod is provided on the upper portion of the gas pressurized hot water pan. (5) A gas pressurization gas passage is provided in the upper part of the gas pressurization pouring pan, and a gas pressurization cylinder for controlling the molten metal pouring speed is connected to the pressurization gas passage. Die-casting according to any one of (1) to (4) And (6) a die casting apparatus according to any one of (1) to (5), further comprising a pressurizing means for pressurizing the molten metal in the mold cavity, and (7) the above A casting method using the die casting apparatus according to any one of (1) to (6), wherein a molten metal is cast into a mold cavity through a casting stalk and a casting sleeve from a gas pressurized pouring pot, and the molten metal is inside the cavity. A die casting method characterized in that the molten metal delivery opening formed in the casting sleeve is closed with a casting plunger and then the molten metal in the mold cavity is pressurized, and (8) the mold. When pressurizing the molten metal in the cavity, the mold opening force or mold opening amount is detected, and when the value becomes larger than the specified value, the pressurizing speed is slowed down and the generated mold opening force is reduced. As described in (7) above Die-casting method, (9) After closing the molten metal delivery opening formed in the casting sleeve with the casting plunger tip, immediately release the gas pressure in the gas pressurized pouring pan to the atmosphere, and at the bottom of the molten metal inlet The die-casting according to (7) or (8) above, wherein the closing member is opened, the molten metal necessary for the next time is supplied to the gas pressurizing pouring pot, and is closed again with the closing member to prepare for the next casting. (10) The above (7) to (9), wherein (10) an inert gas is used as the gas for pressurization, and the gas pressure at the end of casting is controlled to 1 kg / cm ² or more. The die-casting method according to any one of (7) to (10) above, or (11) the die-casting method according to any one of (7) to (10) above, wherein the cast product is a thin and large cast product of a light metal alloy About.

  According to the present invention, the molten mold free of oxide film is filled in the mold cavities within a short time at high speed, the molten metal in the blocked cavities is effectively pressurized, and there is no occurrence of shrinkage nests, and It is possible to provide a die-casting apparatus capable of easily casting a cast product without entrainment of gas, having high work efficiency, easy maintenance, and low equipment cost, and a die-casting method using the die-casting apparatus.

It is a schematic longitudinal cross-sectional view of the die-casting apparatus concerning one Embodiment of this invention. It is explanatory drawing which shows the operating state of the die-casting apparatus shown in FIG. It is explanatory drawing (continuation of FIG. 2) which shows the operation state of the die-casting apparatus shown in FIG. In the die-casting apparatus shown in FIG. 1, it is explanatory drawing which shows the state which opens a type | mold, takes out a cast product, and supplies hot water.

  The die casting apparatus of the present invention includes a fixed mold and a movable mold that form a mold cavity, a cast sleeve that is provided in the fixed mold and communicates with the mold cavity, and is formed on the cast sleeve. Through the molten metal delivery opening, the molten metal is supplied and filled into the mold cavity from below through the casting stalk, and the casting means having a gas pressurized hot pot is slid in the casting sleeve to deliver the molten metal. A die casting apparatus comprising a casting plunger that closes the opening and pressurizes the molten metal, and a hot water furnace, wherein a gas pressurized hot water pan is disposed so as to be immersed in the molten metal in the hot water furnace. The pressure pouring pan is a device that has a molten metal inlet at the bottom and a closing member that can close the molten metal inlet, and is configured to form a sealed structure by closing the molten metal inlet with the closing member. Limited However, the die casting apparatus of the present invention is a die casting apparatus with good work efficiency, easy maintenance and low equipment cost, and by using the die casting apparatus of the present invention, there is no mixing of oxide film, In addition, it is possible to suitably cast a cast product that does not involve gas, particularly a large cast product that is thin and requires strength. And although it is not particularly limited as such a cast product, when casting a thin and large cast product using a light metal alloy, particularly an aluminum alloy that is easily oxidized and has a large solidification shrinkage of about 7%, It can be advantageously applied.

  The die casting apparatus of the present invention may be any of a vertical die casting apparatus in which a fixed mold and a movable mold are arranged up and down, and a horizontal die casting apparatus in which the fixed mold and the movable mold are arranged on the left and right. .

  As the casting means in the die casting apparatus of the present invention, a gas pressurized pouring pan is used to supply and fill the molten metal from below into the mold cavity through the casting stalk through the molten metal delivery opening formed in the casting sleeve. The gas pressurized pouring pan has a molten metal inlet at the bottom and a closing member capable of closing the molten metal inlet, and is configured to close the molten metal inlet with the closing member to form a sealed structure. ing. And a gas pressurization pouring pan is immersed and arrange | positioned in the molten metal in a hot-water supply furnace. Such casting means is, for example, using a hot water supply ladle to introduce molten metal from the molten metal hot water inlet of the pouring pan located outside the apparatus main body, and to form a sealed structure by closing the pan lid, There is little contamination of the oxide film, the work is greatly facilitated, and work efficiency is improved.

  Specifically, for a gas pressurized pouring pan, for example, a closing cylinder that drives a closing member that closes the molten metal inlet is installed in the pan lid at the top of the pan body, and a pressurized gas inlet is provided in the pot lid. Is preferred. Moreover, it is preferable that the casting stalk is provided so as to protrude obliquely from the side portion of the pan body. Furthermore, it is preferable to provide a hot water level detection rod that can detect the hot water level at the tip of the pan lid.

  Since the gas pressurization pouring pot only needs to be able to supply the amount of hot water required for one casting, the inner diameter is preferably about 100 to 300 mm, and more preferably 150 to 250 mm. Moreover, it is preferable that the height is about 400-1000 mm, and it is more preferable that it is about 500-800 mm.

  Since the gas pressurized hot water pot in the present invention has a small diameter and is vertically long, the area of the gas part can be reduced, so that the gas pressure can be increased and the molten metal can be easily filled into the mold cavity. Further, it is possible to supply a molten metal quantitatively to the mold cavities, increase the supply speed, and shorten the shot time lag, thereby enabling high-quality casting and casting of a large cast product. By using such a pouring pot, the production cycle time is shortened, so the productivity is also improved.

  In addition, the gas pressurized pouring pan has a capacity that can accommodate the molten metal required for one casting, so that the amount of molten metal in the pouring pan at each casting is always constant, so there is no need for pressure correction and more accuracy. It is possible to control the filling rate of the molten metal well. 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 necessary for one casting This is effective when there is no need to make such a fine adjustment and it is necessary to make a fine adjustment of the filling speed with a high-quality casting.

  In addition, the gas pressurized hot water pouring pan may be fixed to the apparatus main body, but preferably has a configuration that can be attached to and detached from the apparatus main body in order to facilitate maintenance. As a pan body mounting means for fixing (attaching) the gas pressurized hot water pan to the device body, it is fixed on a surface parallel to the casting stalk so that the inclined casting stalk is stably held by the casting sleeve. A structure that can be attached to a board is preferred. That is, when the gas pressurized pouring pan is detached from the apparatus main body and moved, it is preferable that the gas pressurized pouring pan is first moved parallel to the direction of casting stalk to be detached from the apparatus main body and then moved horizontally. Moreover, although a gas pressurized hot-water pot is immersed in the molten metal in a hot water furnace, it is preferable not to attach directly to a hot water furnace.

  The gas pressurized hot water pouring pan and cast stalk of the present invention are immersed in the molten metal of the hot water furnace, and there is little cooling, thereby suppressing the generation of a solidified layer, good hot water circulation and the occurrence of defective casting products. It is possible to suppress as much as possible.

  Control of the gas (inert gas) introduced into the gas pressurized hot water pan may be performed using a pressure control valve, but the piston speed is adjusted using a pressurized gas introducing means having a gas pressurized cylinder and a piston. It is preferable to carry out by controlling. The piston in the pressurized gas introduction means is preferably driven by a pulse motor controlled by a program. Specifically, the advance and retreat of the piston is accurately controlled by a screw shaft driven by the pulse motor. By using such a pressurized gas introducing means, it is possible to accurately control the pressurized gas and more reliably control the casting speed of the molten metal. For example, when passing through a molten metal delivery opening or outlet gate of a casting sleeve having a small passage area, the molten metal speed is temporarily reduced to prevent the generation of a jet, and at a place where there is no problem even if the casting speed is increased. The casting speed can be increased and casting can be performed at a high speed as a whole, and a high-quality casting can be more reliably manufactured. Further, in the case of thin-wall casting, it is preferable to further have a pressure accumulation tank (accumulator). Also, by utilizing this gas pressurization cylinder, the hot water supply time can be shortened by evacuating the gas pressurization pouring pan during hot water supply.

  Moreover, it is preferable that the casting means includes an exhaust means for discharging the gas in the mold cavities in addition to the gas pressurized hot water pot. The exhaust means may be vacuum suction by a vacuum pump, a high-speed blower, or the like, but has a gas cylinder and a piston, and by controlling the piston speed, the mold cavity is filled with molten metal at a higher speed. In addition, the gas in the mold cavity can be discharged with good control, and the pumping speed can be controlled with high precision even during casting, so that the casting speed can be controlled more accurately. Like the gas introduction means, the piston in the exhaust means is preferably driven by a program-controlled pulse motor, and the advance and retreat of the piston can be accurately controlled by a screw shaft driven by the pulse motor.

  The casting sleeve is particularly limited as long as it is in communication with the mold cavity located above via the exit gate and is attached to and / or formed on the fixed mold. For example, in the case of a saddle type device, a downwardly extending sleeve attached to the lower part of the fixed mold, or a hole formed in the fixed platen and the fixed mold is used. For example, in the case of a horizontal device, a hole formed in a fixed mold, a horizontal hole formed by combining a hole formed in a fixed mold and a movable mold, a fixed mold, and a movable mold A hole formed in a substantially vertical direction in the mating surface portion can be exemplified.

  In the die casting apparatus of the present invention, since the casting sleeve is a short small diameter casting sleeve, the residence time of the molten metal is also very short, there is no generation of a solidified layer due to cooling, and the flow resistance is also small. Filling up to mold cavities can be carried out more smoothly and at a low pressure, and maintenance such as manufacture and cleaning of the apparatus itself is facilitated. The inner diameter of the cast sleeve is, for example, about 50 mm to 150 mm, preferably 80 mm to 120 mm, and the length is, for example, about 100 mm to 200 mm, preferably 120 mm to 160 mm. .

  Further, the tip of the casting sleeve outlet is preferably tapered so that it gradually increases toward the tip, thereby facilitating gas discharge and the solidified layer generated on the inner wall is cast. It is possible to prevent the plunger from being pushed into the mold cavity by the plunger.

  The combination of the casting means and the casting sleeve allows the casting means to be configured to fill the entire mold cavity without using a casting plunger, thereby cooling and solidifying the molten metal. In addition to preventing the solidified layer from mixing, and further preventing the oxide film from mixing, the quality can be further improved.

  The casting sleeve is provided with a molten metal delivery opening, which is a communicating portion with the casting stalk, in the casting sleeve. The shape of the molten metal delivery opening is not particularly limited, but is preferably a quadrilateral with a rounded corner in view of the flow of the molten metal, ease of processing, etc. In this case, the length of one side of the molten metal delivery opening is Stoke. It is preferable to make it smaller than the inner diameter.

  A casting plunger that slides inside the casting sleeve and closes the molten metal delivery opening of the casting sleeve and pressurizes the molten metal closes the molten metal delivery opening to prevent the backflow of the molten metal filled in the mold cavity. Further, it is means for further advancing and pressurizing the molten metal filled in the mold cavity. Examples of the cast plunger include a plunger tip (plunger head) that can slide in an airtight manner in the cast sleeve and a plunger rod that can move the plunger tip forward and backward. As a driving source for the reciprocating motion of the plunger rod, a hydraulic cylinder and a servo motor can be cited. Such a casting plunger is preferably provided through the stationary mold.

  Further, after the plunger tip closes the molten metal delivery opening of the casting sleeve, it is preferable that the molten metal delivery opening be opened when the rear end of the plunger tip advances to the molten metal delivery opening. A gas passage is preferably formed in the plunger rod behind the tip. That is, the communication valve is opened to the gas passage of the plunger rod to feed in gas, and the rear end of the plunger tip reaches the molten metal delivery opening, from a small gap between the plunger tip and the plunger rod. It can be set as the structure which drops the molten metal in cast-in stalk in the pouring pan by ejecting gas. This makes it possible to guide all the molten metal to the lower part of the cast stalk that is immersed in the molten metal of the hot water furnace without leaving the molten metal in the molten metal delivery opening and the upper part of the cast stalk. It is possible to prevent the occurrence of troubles such as squeezing of the molten metal when the plunger tip is retracted and solidification and fixation in the casting stalk. The gas pressure in the gas passage is preferably the same as the pressure of the gas in the pouring pan, and by using an inert gas as the pressurized gas, it is possible to prevent oxidation of the molten metal in the casting stalk. it can.

  Moreover, in the die-casting apparatus of this invention, it is preferable to provide the pressurizing means to pressurize the molten metal in the closed mold cavity. That is, it is preferable to provide a pressurizing means for pressurizing the molten metal in the mold cavity together with the casting plunger. An example of such pressurizing means is a pressurizing pin disposed in the hot water reservoir of the cavity at a position away from the casting sleeve via the mold cavity. It is preferable to provide a plurality of pressure pins, and the diameter is preferably about 2/3 to 1 times the depth of the hot water reservoir portion of the cavity. In this way, by pressurizing the molten metal with the casting plunger and the plurality of pressure pins located at remote positions, the pressure transmission distance to the molten metal in the cavity is shortened, so that the pressure is uniformly applied to the cavity product part. This makes it possible to cast a casting that does not generate any shrinkage when solidified with a small pressure. In addition, by placing the cast plunger and the pressure pin at appropriate positions according to the product form, the pressure transmission distance of the molten metal in the cavity product part is further shortened, and the pressure transmission is made more uniform and sufficient. This can prevent the formation of a sinkhole with a small pressure. Moreover, the die casting apparatus of the present invention can press the molten metal sufficiently with a small pressure, so that it can cope with a mold clamping force of 1/3 to 1/5 that of the conventional high pressure method. The manufacturing cost of the device can be greatly reduced.

  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-described die casting apparatus of the present invention, in which a molten metal is cast into a mold cavity through a casting stalk and a casting sleeve from the gas pressurized pouring pot, After filling the inside, there is no particular limitation as long as it is a method of closing the molten metal delivery opening formed in the casting sleeve with a casting plunger and then pressurizing the molten metal in the mold cavity. In the method, it is preferable that the molten metal is cast by controlling so that the casting speed is lowered when the molten metal passes through the molten metal delivery opening and the outlet gate of the entrance of the mold cavity. Thereby, generation | occurrence | production of a jet flow can be prevented, the entrainment of the gas to a molten metal can be prevented, and an apparatus trouble can be avoided. Also, when pressurizing with a casting plunger or pressurizing means, the mold clamping force or mold opening amount is detected, and if the value becomes larger than the specified value, the pressurizing speed of the casting plunger or pressurizing means It is preferable to perform control to slow down the speed and to reduce the generated mold opening force.

Further, it is preferable to cast the molten metal by controlling the pressure in the gas pressurizing pouring pan at the end of casting to be 1 kg / cm ² or more, thereby shortening the entire casting time and completely Filling can be performed to produce high quality castings.

  In addition, after closing the molten metal delivery opening formed in the casting sleeve with the casting plunger, immediately release the gas pressure in the gas pressurized hot water pan to the atmosphere, and open the closing member of the molten metal inlet at the bottom of the pan, It is preferable to supply the molten metal necessary for the next time to the gas pressure pouring pot, close the closing member of the molten metal inlet again, and prepare for the next casting. For example, the blocking member can be closed at the timing when the molten metal surface comes into contact with the tip of the molten metal surface detection rod.

  Hereinafter, although the die-casting apparatus of this invention is demonstrated with reference to drawings, the technical scope of this invention is not limited to these.

  FIG. 1 is a schematic longitudinal sectional view of a die casting apparatus according to an embodiment of the present invention. FIGS. 2 and 3 are explanatory views showing the operating state of the die casting apparatus shown in FIG. 1, and FIG. In the die-casting apparatus shown in FIG. 2, it is explanatory drawing which shows the state which opens a type | mold, takes out a cast, and supplies hot water.

  As shown in FIGS. 1 and 4, the die casting apparatus according to one embodiment of the present invention is capable of moving and performing mold closing by moving with a fixed mold 1 attached to a fixed plate 3 of the casting apparatus. A movable mold 2 mounted on a movable platen 4 via a movable mold holder 15, and a gas pressurizing pouring pot 7 disposed obliquely below an apparatus main body including the fixed mold 1 and the movable mold 2. The pressurized gas pouring pan 7 is immersed in the molten metal of the hot water furnace 26. A mold cavity C is formed by the fixed mold 1 and the movable mold 2.

  The gas pressurized hot water pouring pan 7 has a molten metal inlet 7 a at the bottom and a lid 20 that can seal the gas at the top so that an oxide film present on the hot water surface of the hot water furnace 26 does not flow. The lid 20 is provided with a driving cylinder 21 for advancing and retracting a rod-like closing member 7b for closing the molten metal inlet 7a, and a hot water level detecting rod 8 for detecting the hot water level in the hot water furnace 26 at its tip, and pressurizing. A gas inlet 7c for supplying gas is provided. A cast stalk 9 is provided on the side of the pan body. The lower end inlet of the casting stalk 9 is arranged below the hot water surface in the pan that descends during a single pouring of the mold cavity C. When the molten metal is sent out, the gas pressurized pouring pan 7 Even if oxide films are present on the inner surface of the molten metal, they are not mixed into the mold cavity C through the casting stalk 9. In the die casting apparatus of the present invention, the introduction of the molten metal into the gas pressurized hot pot 7 is performed from the molten metal inlet 7a at the bottom, and the inert gas is used as the pressurized gas. There is no possibility that the hot water surface in the hot water pan 7 is oxidized. Further, most of the main body of the gas pressurizing pouring pan 7 and the lower portion of the cast stalk 9 are immersed in the molten metal in the hot water furnace 26, and the temperature of the molten metal in the gas pressurized pouring pan 7 and the cast stalk 9 is reduced and solidified. Layer generation is prevented.

  The fixed mold 1 is provided with an exit gate C2 of a casting sleeve 5, and a casting sleeve 5 is provided below the outlet gate C2, and a diameter of the casting stalk 9 is formed on a side portion thereof. A molten metal delivery opening 51 having a smaller dimension is formed. The casting sleeve 5 and the casting stalk 9 communicate with each other through the molten metal delivery opening 51.

  Further, a casting plunger 6 driven by a casting plunger hydraulic cylinder 18 is provided in the casting sleeve 5, and the mold cavity C is completely filled with molten metal by the casting means (filling) ), The casting plunger 6 is moved forward by the hydraulic cylinder 18 to close the molten metal delivery opening 51, and subsequently moved forward to pressurize the molten metal for the solidification shrinkage volume in the mold cavity C from the casting sleeve 5. To do. A gas passage 64 is formed in the plunger rod 61 behind the plunger tip 63. After introducing the gas into the gas passage 64 from the same path (gas pressurizing cylinder 22) as the gas to be introduced into the gas pressurizing pouring pan 7, the rear end of the plunger tip 63 reaches the molten metal delivery opening 51, By causing gas to be ejected from a small gap between the plunger tip 63 and the plunger rod 61, the molten metal in the casting stalk 9 is surely dropped into the gas pressurized hot water pouring pan 7.

  One or two or more small hot water reservoirs 14 are formed at the end of the mold cavity C, and a pressure pin 11 driven by a hydraulic cylinder 12 is introduced into the hot water reservoir 14, Pressurize the molten metal in the mold cavity C. That is, the pressurizing pins 11 are pushed out together with the casting plunger 6 to pressurize the molten metal in the mold cavity C through the hot water reservoir of the cavity C. The outer diameter of the pressure pin 11 is slightly smaller than the diameter of the hot water reservoir 14 of the cavity. In addition, it is desirable to provide these pressurizing pins 11 near an end portion where the pressurizing pressure by the casting plunger 6 is difficult to reach or a portion requiring strength.

  Next, the operation and casting method of the above-described die casting apparatus will be described. As shown in FIGS. 1 and 2, when the molten metal inlet at the bottom of the gas pressurized pouring pan 7 where hot water supply has been completed is closed, the gas pressure applied to the molten metal surface in the gas pressurized pouring pan 7 and the gas exhaust means Due to the vacuum suction from the gas discharge port 13, the molten metal in the gas pressurized pouring pan 7 is filled into the mold cavity C through the casting stalk 9, the molten metal delivery opening 51, the casting sleeve 5 and the outlet gate C <b> 2.

  At this time, the casting speed is controlled to fill the mold cavity C with the molten metal. By introducing the pressurized gas into the gas pressurized hot pot 7 using the pressurized gas introducing means by the gas pressure cylinder 22, the casting speed can be controlled more accurately.

  That is, in the casting stage of the molten metal, it is necessary to complete the filling of the mold cavities C within a short time when the molten metal does not cool and solidify. It pushes up quickly until it reaches, but when the molten metal passes through the molten metal delivery opening 51, it is not filled with vigor, but the casting speed is slowed down so that the molten metal is inserted into the plunger tip 63 as shown in FIG. It is filled so as not to leave the tip of the gas so as not to entrain the gas. Further, when the hot water passes through the exit gate C2, if it is rapidly filled, the molten metal becomes a jet and collides with each part of the cavity and entrains the gas. Therefore, as shown in FIG. Until the molten metal accumulates in the surrounding area, the speed is controlled so as not to entrain gas.

As described above, when the molten metal tip rises in the casting stalk 9, the molten metal is pushed in as soon as possible. When the molten metal is allowed to pass through the molten metal delivery opening 51 at a speed such that the lower surface of the molten metal is not lifted from the tip of the plunger tip, Gradually increase the speed to a range that does not jump into the tank, fill the casting sleeve 5, reduce the speed again when the hot water passes through the outlet gate C2, and increase the casting speed when filling the cavity C. The entire filling time is shortened to complete the filling. Especially in the case of thin-wall casting, filling is performed at high speed within a short time. When this filling is completed, it is effective for completely filling and preventing the formation of shrinkage cavities that the gas pressure in the gas pressurized pouring pan 7 is at a pressure of 1 kg / cm ² or more and pressurizing the molten metal.

  When the flow of the molten metal in the mold cavity C stops when filling is completed and the pressure of the pressurized gas rises, this is detected as a filling completion signal, and the molten metal delivery opening 51 is immediately closed by the casting plunger 6; Pressurize the molten metal in the casting sleeve 5. At this time, as shown in FIG. 3A, when the rear end of the cast plunger tip 61 reaches the molten metal delivery opening 51, the pressurized gas flows into the cast stalk 9, and the molten metal in the cast stalk 9 is obtained. Falls to the surface of the gas pressurizing pouring pan 7.

  On the other hand, as shown in FIG. 3B, in the mold cavity C, since the solidification shrinkage of the molten metal occurs, the casting plunger 6 is advanced, and further, as shown in FIG. The pressurization pin 11a and the pressurization pin 11b are advanced to perform replenishment according to the coagulation contraction volume. Since the pressure replenishment according to the solidification shrinkage volume due to the advancement of the casting plunger 6 may be difficult to transmit pressure to the opposite end of the mold cavity C, the pressurizing pin 11b around the end is operated. By applying pressure, a product having a dense structure free from shrinkage due to coagulation shrinkage can be obtained. Next, as shown in FIG. 4, after the cooling and solidification of the molten metal in the mold cavity C is completed, the mold is opened, and the product material lifted by the movable mold is extruded by the pressure pins and the extrusion pins, It can be taken out.

DESCRIPTION OF SYMBOLS 1 Fixed die 2 Movable die 3 Fixed platen 4 Movable platen 5 Casting sleeve 51 Molten metal delivery opening 6 Casting plunger 61 Casting plunger rod 63 Casting plunger tip 64 Rod gas passage 7 Gas pressurization pouring pan 7a Molten inlet 7b Molten inlet closing plug 7c Pressurized gas inlet 8 Hot water level detection rod 9 Cast stalk 11a Central pressure pin 11b End pressure pin 12a Central pressure pin hydraulic cylinder 12b End pressure pin hydraulic Cylinder 13 Gas exhaust port 14a Center pressure pin hot water reservoir 14b End pressure pin hot water reservoir 15 Movable mold holder 16 Pressure plate 17 Extrusion plate 18 Casting plunger hydraulic cylinder 19 Gas pressure hot water pot holding device 20 Pot lid 21 Blocking plug cylinder 22 Gas pressurizing cylinder 23 Gas pressurizing piston drive hydraulic cylinder 25 Molten metal supply 26 Hot water furnace 2 7 Gas valve C Mold cavity C2 Exit gate C3 Overflow M Molten metal

Claims (11)

A fixed mold and a movable mold forming a mold cavity; and
A casting sleeve provided in the fixed mold and communicating with the mold cavity;
Casting means equipped with a pressurized gas pouring pot for supplying and filling the molten metal into the mold cavity from below through the casting stalk through the molten metal delivery opening formed in the casting sleeve;
A casting plunger that slides in the casting sleeve and closes the molten metal delivery opening and pressurizes the molten metal;
A water heater,
A die casting apparatus comprising:
A gas pressurized pouring pan is disposed so as to be immersed in the molten metal in the hot water furnace, and the gas pressurized pouring pan has a closing member that has a molten metal inlet at the bottom and can close the molten metal inlet. A die casting apparatus, wherein the molten metal inlet is closed to form a sealed structure.   The gas pressurized pouring pan has a cast stalk provided to project obliquely upward from the side of the pan body, and is configured to be attached to and detached from the apparatus body together with or separately from the hot water furnace. The die-casting apparatus according to claim 1.   The die casting apparatus according to claim 1 or 2, wherein the capacity of the gas pressurized pouring pan is a capacity capable of accommodating a molten metal required for one casting.   The die-casting apparatus according to any one of claims 1 to 3, wherein a hot water level detection rod is provided at an upper portion of the gas pressurized pouring pan.   The pressurized gas passage is provided in the upper part of the pressurized gas pouring pan, and a gas pressurizing cylinder for controlling the molten metal pouring speed is connected to the pressurized gas passage. The die-casting apparatus of crab.   The die casting apparatus according to any one of claims 1 to 5, further comprising a pressurizing unit that pressurizes the molten metal in the mold cavity.   A casting method using the die casting apparatus according to any one of claims 1 to 6, wherein a molten metal is cast into a mold cavity through a casting stalk and a casting sleeve from a gas pressurized pouring pot, and the molten metal fills the cavity. Then, the molten metal delivery opening formed in the casting sleeve is closed with a casting plunger, and then the molten metal in the mold cavity is pressurized.   When pressurizing the molten metal in the mold cavity, detect the mold opening force or the amount of mold opening, and if the value exceeds the specified value, slow down the pressurizing speed and reduce the generated mold opening force. The die-casting method according to claim 7.   After closing the molten metal delivery opening formed in the casting sleeve with the casting plunger tip, immediately release the gas pressure in the gas pressurized pouring pan to the atmosphere and open the closing member of the molten metal inlet at the bottom, next time The die casting method according to claim 7 or 8, wherein a necessary molten metal is supplied to a gas pressure pouring pot and closed again with a closing member to prepare for the next casting. The die-casting method according to any one of claims 7 to 9, wherein an inert gas is used as the pressurizing gas, and the gas pressure at the end of casting is controlled to 1 kg / cm ² or more to perform casting. .   The die casting method according to any one of claims 7 to 10, wherein the cast product is a light metal alloy thin-walled and large-sized cast product.

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