JP2013035008A - Die casting machine and die casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die casting machine which can simply manufacture castings without any shrinks and any gas entrainment, by pouring molten metal in which oxide film is not mixed into a mold cavity in a short time and effectively pressurizing the molten metal in the closed cavity, wherein the die casting machine is a small size, has high working efficiency, is easy in maintenance, and is low in installation costs.SOLUTION: The die casting machine includes: a fixed mold 1 and a movable mold 2; a casting sleeve 5 which is provided on the fixed mold 1 and communicates with the mold cavity C; a casting means with a pressurized molten metal pouring pump 7, which pours the molten metal from below into the mold cavity C through a casting stalk via the casting sleeve 5; a casting plunger 6 which slides in the casting sleeve 5; and a hot water supply furnace 26. In the die casing machine, the pressurized molten metal pouring pump 7 having a pressurized molten metal pouring plunger 8 is arranged which is dipped in the molten metal inside the hot water supply furnace 26. The pressurized molten metal pouring pump 7 has a molten metal inflow port 7a at the bottom and includes a blocking member 7b capable of blocking the molten metal inflow port 7a. The molten metal inflow port 7a is blocked by the blocking member 7b, so that a sealed structure is formed.

Description

  The present invention is capable of casting a cast product such as a light metal alloy, and is a die-casting apparatus that supplies and fills molten metal into the mold cavity from below, in particular, the molten metal is poured into the mold cavity from below using a pressurized pouring pump. 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 in a short time, with the molten metal free from oxide film mixed in, at a high speed, effectively pressurize the molten metal in the closed cavities, and It is an object of the present invention to provide a die-casting method capable of easily casting a cast product free from gas and having no gas entrainment, having high work efficiency, easy maintenance, and low equipment cost.

  As a result of diligent research to solve the above-mentioned problems, the present inventor has a closing member that has a molten metal inlet at the bottom and can close the molten metal inlet, and closes the molten metal inlet with the closing member to form a sealed structure. By immersing a pressurized pouring pump equipped with a pouring plunger, which is configured to form, in the molten metal of the hot water furnace, it prevents contamination of the oxide film on the molten metal surface and prevents a decrease in the hot water temperature. By applying pressure to this pouring plunger, it is possible to make a device with good work efficiency, easy maintenance, and low equipment costs, and a pouring plan for such a pouring pump. By increasing the pressure of the jar, the molten metal can be supplied at high speed in a short time, and even a thin wall can be completely filled, and a cast product without oxide film contamination and gas entrainment can be cast. It found, which resulted in the completion of the present invention. 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 was found that when the pressure was increased, the solidification shrinkage volume was replenished, no shrinkage was generated, and a cast product without oxide film mixing and gas entrainment could be cast, and the present invention was completed.

That is, the present invention
(1) a fixed mold and a movable mold that form a mold cavity;
A casting sleeve provided in the fixed mold and communicating with the mold cavity;
A casting means equipped with a pressurized pouring pump 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 die casting apparatus comprising a hot water furnace,
A pressurized hot water pump provided with a hot water pressure plunger that is immersed in the molten metal in the hot water furnace is disposed. The pressurized hot water pump has a molten metal inlet at the bottom and can close the molten metal inlet. A die casting apparatus characterized by comprising a closing member, and configured to close the molten metal inlet with the closing member to form a sealed structure,
(2) The pressurized pouring pump has a cast stalk provided so as to project obliquely upward from the side of the pump case body, and can be attached to and detached from the apparatus body together with or separately from the hot water furnace. The die-casting apparatus according to (1) above,
(3) The die casting apparatus according to (1) or (2) above, wherein the capacity of the pressurized pouring pump is a capacity capable of accommodating the molten metal required for one casting,
(4) The die casting according to any one of the above (1) to (3), wherein the tip of the pouring plunger of the hot pouring pump is located below the hot water surface of the hot water furnace. Equipment,
(5) The molten metal pouring plunger of the pressurized pouring pump is connected to a pressurizing cylinder for controlling the molten metal pouring speed, as described in any one of (1) to (4) above Die casting equipment,
(6) The die-casting apparatus according to any one of (1) to (5) above, which includes a pressurizing unit that pressurizes the molten metal in the mold cavity.
(7) A casting method using the die casting apparatus according to any one of (1) to (6) above, in which a molten metal is cast into a mold cavity through a casting stalk and a casting sleeve from a pressurized pouring pump, After the molten metal fills the cavity, 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,
(8) When pressurizing the molten metal in the mold cavity, the mold opening force or mold opening amount is detected. If the value becomes larger than the specified value, the pressurizing speed is slowed down to reduce the generated mold opening force. The die-casting method according to (7) above, characterized in that it is reduced,
(9) After closing the molten metal delivery opening formed in the casting sleeve with the casting plunger tip, immediately close the closing member of the molten metal inlet at the bottom and retreat the molten metal pressure plunger of the pressurized hot water pump The die casting method according to (7) or (8) above, wherein the molten metal necessary for the next time is supplied into the pressure pouring pump, and is closed again with the closing member to prepare for the next casting,
(10) In any one of the above (7) to (9), a plunger for pouring hot water is used, and the plunger pressure at the end of casting is controlled to 1 kg / cm ² or more to perform casting. The described die-casting method,
(11) The die casting method according to any one of (7) to (10), wherein the cast product is a light metal alloy thin and large cast product.

  According to the present invention, the mold cavity is filled with a molten metal that is not mixed with an oxide film at high speed in a short time, the molten metal in the closed cavity is effectively pressurized, no shrinkage occurs, and the gas It is possible to provide a die-casting apparatus capable of easily casting a cast product without entrainment, 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, through the casting stalk, the molten metal is supplied and filled into the mold cavity from below, and a casting means having a pressurized pouring pump 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, and is a pressurized molten metal that is immersed in the molten metal in the hot water furnace and includes a molten metal pressure plunger. The pump is arranged, and the pressurized pouring pump has a melt inlet at the bottom and a closing member capable of closing the melt inlet, and is configured to close the melt inlet with the closing member to form a sealed structure Been The die-casting apparatus of the present invention is a die-casting apparatus with good working efficiency and easy maintenance, and the equipment cost is low, and the die-casting apparatus of the present invention is used. Thus, it is possible to suitably cast a cast product that does not contain an oxide film and does not involve gas, particularly a large-sized 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 a casting means in the die-casting apparatus of the present invention, a molten metal pressure plunger that feeds and fills the molten metal from below into the mold cavity through the molten metal delivery opening formed in the casting sleeve. The pressure pouring pump has a molten metal inlet at the bottom and a closing member capable of closing the molten metal inlet, and the molten metal inlet is closed by the closing member. It is comprised so that a sealing structure may be formed, and it 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, the pressure pouring pump has, for example, a pouring pressure plunger that slides in a case of the pouring pump, and a pressure cylinder that drives the pouring pressure plunger is installed above the plunger. . A closing member that closes the molten metal inlet is slidably provided in the center of the pouring plunger, and a closing cylinder is provided above the closing member.

  Moreover, it is preferable that the casting stalk protrudes diagonally from the side part of the pump case body. Furthermore, it is preferable that the tip in the retreat limit of the pouring plunger is below the hot water surface of the hot water furnace.

  Since the pressure pouring pump only needs to be able to supply the amount of hot water required for one casting, the inner diameter of the pump case main body (diameter of the pouring plunger) is preferably about 100 to 300 mm, and 150 to 250 mm. It is more preferable that Moreover, it is preferable that a stroke is about 200-600 mm, and it is more preferable that it is about 300-500 mm.

In the pressurizing pouring pump of the present invention, even in the case of thin-walled products, the maximum pressure during pouring is sufficient to be ³ to 5 kg / cm ² , and the case diameter can be reduced by making the pump case small and vertically long Even if the pump case is made of heat-resistant ceramic, the pressure strength can be secured, the molten metal pouring pressure can be increased, and the molten metal can be easily filled into the mold cavity. It is possible to supply the molten metal to the cavity in a quantitative manner, increase the supply speed, and shorten the shot time lag, enabling high-quality casting and casting of a large casting. By using such a pressurized pouring pump, the production cycle time is shortened, so that productivity is also improved.

  In addition, the pressure pouring pump has a capacity that can accommodate the molten metal required for one casting, so that the amount of the molten metal in the pressurized pouring pump at each casting is always constant, so there is no need to perform pressure correction, The molten metal filling rate can be controlled more accurately. 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.

  The pressurized hot water pump 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 case body attachment means for fixing (attaching) the pressurized pouring pump 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 pressurized pouring pump is detached from the apparatus main body and moved, it is preferable to first move it in parallel with the direction of casting stalk and remove it from the apparatus main body, and then move it horizontally. Moreover, although a pressurized hot water pump is immersed in the molten metal in a hot water furnace, it is preferable not to attach directly to a hot water furnace.

  The pressurized pouring pump and the 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, the hot water circulation is good, and the casting product is not defective. It is possible to suppress as much as possible.

  It is preferable to control the hot water pressure plunger for driving the pressure hot water pump by controlling the piston speed using a pressure cylinder and a piston. The piston is preferably driven by a program-controlled pulse motor. Specifically, the advance and retreat of the pouring plunger is accurately controlled by a screw shaft driven by the pulse motor. By using such speed control means, the casting speed of the molten metal can be controlled more reliably. 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 high speed within a short time 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 pour hot water at a higher speed. In addition, by using this pressure cylinder, the hot water supply plunger can be pulled up during hot water supply to evacuate the pressure hot water pump to shorten the hot water supply time.

  Moreover, it is preferable that the casting means includes an exhaust means for discharging the gas in the mold cavity in addition to the pressurized hot water pump. The exhaust means may be vacuum suction using a vacuum pump, a high-speed blower, or the like.

  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.

  Further, the casting sleeve is provided with a molten metal delivery opening which is a communicating portion with the casting stalk. 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 is 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 supply gas is ejected from a small gas container and is initially expanded at a high pressure in the casting stalk and is preferably at atmospheric pressure. By using an inert gas as the pressurized gas, the molten metal in the casting stalk is oxidized. Can be prevented.

  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. In addition, the die casting apparatus of the present invention can press the molten metal sufficiently with a small pressure, and can detect the mold opening force or the amount of mold opening and control the pressing speed to control the conventional high pressure method. Therefore, it is possible to cope with the mold clamping force of 1/3 to 1/5, and the manufacturing cost of the casting apparatus 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 pressurized pouring pump. 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 of the molten metal pressure plunger of the pressurized molten metal pump at the end of casting to be 1 kg / cm ² or more, thereby shortening the entire casting time. In addition, complete filling can be performed to produce a high-quality cast product.

  In addition, after closing the molten metal delivery opening formed in the casting sleeve with the casting plunger, immediately after opening the closing member of the molten metal inlet at the bottom of the pump case, It is preferable that the molten metal necessary for the next time is moved backward and supplied into the pressurized pouring pump, and the closing member of the molten metal inlet is closed again to prepare for the next casting. The closing of the closing member can be performed, for example, at a timing when the pouring plunger has reached the retreat limit.

  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 an 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 product, 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 pressurized pouring pump 7 disposed obliquely below an apparatus main body including the fixed mold 1 and the movable mold 2. The pressurized pouring pump 7 is immersed in the molten metal of the hot water supply furnace 26. A mold cavity C is formed by the fixed mold 1 and the movable mold 2.

  The pressurized pouring pump 7 has a molten metal inlet 7 a at the bottom and a molten metal inlet plunger 8 for pushing out the molten metal at the top so as not to allow an oxide film present on the hot water surface of the hot water furnace 26 to flow. A pressure cylinder 22 is provided. A rod-like closing member 7b that closes the molten metal inlet 7a passes through the pouring plunger 8 at the center, and a driving cylinder 21 is provided above the rod-like closing member 7b. A cast stalk 9 is provided on the side of the pump case body. The lower end inlet of the casting stalk 9 is disposed below the hot water surface (tip of the hot water pressurizing plunger 8) in the pressurizing hot water pump 7 that descends during one pouring of the mold cavity C. When the molten metal is sent out, even if an oxide film is present on the molten metal surface in the pressurized pouring pump 7, they are not mixed into the mold cavity C through the casting stalk 9. In the die casting apparatus of the present invention, the molten metal is introduced into the pressurized pouring pump 7 from the molten metal inlet 7a at the bottom, and the tip of the molten metal pressure plunger 8 is always on the surface of the hot water of the hot water furnace. There is no possibility that the inside of the pressurized pouring pump 7 is evacuated, the outside air flows in, and the hot water surface is oxidized. The main part of the pouring gas pressurizing and pouring pump 7 and the lower part of the casting stalk 9 are immersed in the molten metal of the hot water furnace 26, and the temperature of the molten metal inside the pressurized pouring pump 7 and the casting stalk 9. Reduction and generation of a solidified layer are 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. An inert gas is introduced into the gas passage 64 from a small-capacity gas container so that the rear end of the plunger tip 63 reaches the molten metal delivery opening 51, and then between the plunger tip 63 and the plunger rod 61. By ejecting gas from a small gap, the molten metal is reliably dropped into the pressurized pouring pump 7 without making the pressure in the casting stalk 9 vacuum. At this time, the volume of the gas container is reduced, and the volume is expanded within the casting stalk to become atmospheric pressure so that the molten metal surface is not pushed down abnormally.

  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 pressurized pouring pump 7 where hot water supply is completed is closed, the pouring plunger 8 applied to the molten metal surface in the pressurized pouring pump 7 is changed. The molten metal in the pressurized pouring pump 7 is moved forward by the vacuum suction from the gas discharge port 13 by the gas exhaust means, and the mold cavity C is passed through the casting stalk 9, the molten metal delivery opening 51, the casting sleeve 5 and the outlet gate C2. It is filled in.

  At this time, the casting speed is controlled to fill the mold cavity C with the molten metal. By pouring the pouring plunger 8 in the hot pouring pump 7 with the pressurizing 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 during which 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, but when reaching the front of the molten metal delivery opening 51, the molten metal is decelerated to such an extent that the molten metal does not jump out due to inertia. When the molten metal is allowed to pass through the molten metal delivery opening 51 at a speed that prevents the lower surface of the molten metal from being lifted from the tip of the plunger tip 63, Gradually increase the speed to a range that does not jump into C2, 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 Then, the entire filling time is shortened and the filling is completed. 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 pressure of the pouring plunger 8 in the pressurized pouring pump 7 is 1 kg / cm ² or more and pressurizing the molten metal. It is.

  When the flow of the molten metal in the mold cavity C stops when the filling is completed and the pressure of the pouring plunger 8 rises, this is detected as a filling completion signal, and the molten metal delivery opening 51 is immediately detected by the casting plunger 6. And the molten metal in the casting sleeve 5 is pressurized. At this time, as shown in FIG. 3 (a), when the rear end of the casting plunger tip 63 reaches the molten metal delivery opening 51, the inert gas flows into the casting stalk, and the molten metal inlet closing plug is opened. The hot water pressure plunger 8 moves backward and rises, and the molten metal in the casting stalk 9 falls to the hot water surface in the pressurized hot water pump 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 metal mold 2 Movable metal mold 3 Fixed disk 4 Movable disk 5 Casting sleeve 51 Molten metal delivery opening 6 Casting plunger 61 Casting plunger rod 63 Casting plunger tip 64 Rod gas passage 7 Pressurizing pouring pump 7a Molten inlet 7b Molten inlet closing plug 8 Pouring plunger 9 Pouring stalk 11a Central pressure pin 11b End pressure pin 12a Central pressure pin hydraulic cylinder 12b End pressure pin hydraulic cylinder 13 Gas exhaust Mouth 14a Central pressure pin hot water reservoir 14b End pressure pin hot water reservoir 15 Movable mold holder 16 Press plate 17 Extrusion plate 18 Casting plunger hydraulic cylinder 19 Pressurizing hot water pump holding device 20 Pan lid 21 Capping plug cylinder 22 Molten water pressurizing plunger 25 Cylinder for pressurization 25 Molten metal supply bowl 26 Hot water supply furnace 27 Gas valve 28 Small inert gas container 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;
A casting means equipped with a pressurized pouring pump 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 die casting apparatus comprising a hot water furnace,
A pressurized hot water pump provided with a hot water pressure plunger that is immersed in the molten metal in the hot water furnace is disposed. The pressurized hot water pump has a molten metal inlet at the bottom and can close the molten metal inlet. A die casting apparatus comprising a closing member, wherein the molten metal inlet is closed by the closing member to form a sealed structure.   The pressure pouring pump has a cast stalk provided to project obliquely upward from the side of the pump case 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 pressurized pouring pump 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 tip end of the pouring plunger of the hot pouring pump is located below the hot water surface of the hot water furnace.   The die casting apparatus according to any one of claims 1 to 4, wherein a pouring plunger of the pouring pump is connected to a pressurizing cylinder for controlling a molten metal pouring speed.   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.   It is a casting method using the die-casting apparatus in any one of Claims 1-6, Comprising: A molten metal is cast in a mold cavity through a casting stalk and a casting sleeve from a pressurized pouring pump, and the molten metal fills the inside of 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 open the closing member of the molten metal inlet at the bottom and retreat the molten metal pressure plunger of the pressurized hot water pump. The die casting method according to claim 7 or 8, wherein a molten metal necessary for the above is supplied into a pressurized pouring pump 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 a plunger for pouring hot water is used, and the plunger 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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