BACKGROUND OF THE INVENTION [0002] Die-casting mold apparatuses are widely used for mass production of metal products, in which a cavity formed by a stationary mold and a movable mold is filled with a molten metal and hardened to become a metal product.
In such a die casting mold apparatus, in the process of filling the molten metal into the cavity, the gas (gas formed by pyrolyzing air or a releasing agent) existing in the cavity and the gas injected into the cavity together with the molten metal are not discharged to the outside, An uncharged defect such as a so-called cavity or pin hole is generated in the metal product, so that the strength of the metal product is lowered and the quality of the weld is lowered when the metal product is welded to another product. Therefore, there is a need for an apparatus for preventing the gas and molten metal present in the cavity from being mixed with the molten metal into the cavity.
Figs. 1 to 3 show an example of a die casting mold apparatus having an apparatus for preventing gas from being mixed into molten metal.
This die casting mold apparatus 1A is provided with a stationary mold 1 fixed to a die casting molding machine and a die casting molding machine 1 reciprocally movable in a direction A in which the stationary mold 1 is closely contacted with and spaced from the stationary mold 1. [ (Not shown). When the stationary mold 1 and the movable mold 2 are brought into close contact with each other, a cavity 3, which is a space in which a metal product is molded, is formed between the molds 1 and 2. The cavity 3 is connected to a vacuum tank T1 in which a vacuum state is maintained by a vacuum pump P1 through a flow path R1 and a valve for opening and closing the flow path R1 V1) are installed. Reference numeral 15 denotes an injection cylinder provided in the stationary mold 1 for injecting molten metal (molten metal) M1 into the cavity 3.
The ejection plate 4 is disposed on the back side of the movable mold 2. As shown in Fig. The eject plate 4 is coupled to a rod 9 reciprocated by a hydraulic mechanism (not shown) and can be moved forward or backward with respect to the movable mold 2 together with the rod 9. One end of a plurality of eject pins 5 slidably inserted into the through hole 2a of the movable mold 2 is fixed to the eject plate 4. [
The ejection plate 4 and one end of the plurality of ejection pins 5 (end portions fixed to the ejection plate) are surrounded by the enclosure 7 coupled to the back surface of the movable mold 2. The space in which the ejection plate 4 and one ends of the ejection pins 5 are disposed is sealed by the enclosure 7, thereby forming the closed space 8. The closed space 8 is connected to the vacuum tank T2 through which the vacuum state is maintained by the vacuum pump P2 through the flow path R2 and the flow path R2 is connected with a valve for opening / (V2). There is a fear that a gap may be generated between the enclosure 7 and the member that contacts the enclosure 7, such as between the enclosure 7 and the movable mold 2, between the enclosure 7 and the rod 9 An appropriate sealing member such as a rubber ring or the like may be provided to prevent the gap.
When the movable mold 2 is brought into close contact with the stationary mold 1 as shown by the solid line in Fig. 1 and the molten metal M1 is injected into the cavity 3 by the injection cylinder 15 and charged, The molten metal in the cavity 3 is hardened and becomes a metal product M having a shape corresponding to the cavity 3 as shown in Fig. 3, when the movable mold 2 is separated from the stationary mold 1, the metal product M is attached to the movable mold 2 in a state of being attached to the movable mold 2. In this state, And are spaced apart from the stationary mold 1. In this state, when the rod 9 and the eject plate 4 coupled to the rod 9 are advanced in a direction approaching the movable mold 2 as shown by a virtual line in Fig. 3, The metal articles M attached to the movable mold 2 are pushed out and separated while the metal molds 5 are advanced together with the eject plate 4. [ After the metal product M is separated, the mold releasing agent is sprayed to the cavity surface (the surface forming the cavity 3) of each of the molds 1 and 2, and then the movable mold 2 is moved to the stationary mold 1 And the eject plate 4 is retreated to repeat the above-described metal product molding process.
On the other hand, while the molten metal M1 is being injected into the cavity 3, the gas (gas formed by pyrolyzing air or a releasing agent) in the cavity 3 and the gas injected into the cavity together with the molten metal are mixed in the molten metal The valve V1 is opened. Then, the vacuum in the vacuum tank T1 causes the gas in the cavity 3 to be sucked along the flow path R1 toward the vacuum tank T1, and as a result, the gas is prevented from being mixed with the molten metal Unfilled defects of the metal product can be suppressed. On the other hand, in the course of the suction of the gas in the cavity 3 into the vacuum tank T1, through the through hole 2a of the movable mold 2 (specifically, the inner peripheral surface of the through hole 2a and the ejection pin 5), the air on the back side of the movable mold 2 may be introduced into the cavity 3. [ Therefore, before the valve V1 is opened, the valve V2 is firstly opened to allow the gas in the closed space 8 to flow toward the vacuum tank T2 along the flow path R2 in advance by the vacuum pressure in the vacuum tank T2 Suction and discharge. Thereby, even if the gas in the cavity 3 is sucked toward the vacuum tank T1 and the cavity 3 is evacuated, there is almost no gas flowing into the cavity 3 from the closed space 8.
When the closed space 8 is evacuated while the gas in the closed space 8 is discharged to the side of the vacuum tank T2 as described above, It has been confirmed by the present inventor that the mold releasing agent or moisture around the cavity surface flows into the closed space 8 through the clearance between the through hole 2a of the movable mold and the eject pins 5.
A part of the mold releasing agent or moisture introduced into the closed space 8 flows into the closed space 8 and is discharged from the closed space 8 to the vacuum tank T2 by the vacuum pressure of the vacuum tank T2, And remains in the closed space 8. The residual mold releasing agent and moisture are heated in the liquid state by the movable mold 2 at a high temperature and are accumulated in the closed space 8. The valve V2 is opened to evacuate the gas in the closed space 8, When the degree of vacuum in the space 8 becomes high (that is, when the vacuum pressure of the vacuum tank T2 acts in the closed space 8 to lower the pressure in the closed space 8) Lt; / RTI > The vaporized liquid (mold releasing agent, moisture, etc.) is evacuated from the closed space 8 and discharged to the side of the vacuum tank T2 when the vacuum pressure of the vacuum tank T2 is applied. However, as the die casting molding operation continues, the amount of the liquid that remains in the liquid state in the closed space 8 increases, and accordingly, the amount of vaporization in the closed space 8 gradually increases as described above. When the amount of the liquid vaporized in the closed space 8 is increased, the pressure in the closed space 8 is increased, so that the burden of the vacuum tank T2 is increased. In addition, The vaporized gas can not be exhausted from the closed space 8 and a part of the gas may be introduced into the cavity 2 and mixed into the molten metal M. [
Hereinafter, a high vacuum die casting mold apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
4 is a schematic cross-sectional view of a high vacuum die casting mold apparatus according to an embodiment of the present invention. FIG. 5 is a schematic exploded perspective view of the enclosure shown in FIG. 4, and FIG. 6 is a schematic enlarged cross-sectional view of the container member portion shown in FIG. 7 is a sectional view taken along line VII-VII in FIG.
4 to 7, the high vacuum die casting mold apparatus 10 of the present embodiment is similar to the die casting mold apparatus 1A described with reference to Figs. 1 to 3 except that the stationary mold 1, the movable mold 2, An eject plate 4, and a plurality of eject pins 5. As shown in Fig. Among the constituent elements of the high vacuum die casting mold apparatus 10 of the present embodiment, the constituent elements having the same configuration and function as those of the die casting mold apparatus 1A described with reference to Figs. 1 to 3 The same reference numerals are given to each other, and a detailed description of each structure or function may be omitted.
The fixed mold 1 and the movable mold 2 are arranged to face each other in a die casting molding machine (not shown), and the movable mold 2 is fixed to the fixed mold 1 by a driving source (not shown) (Hereinafter, referred to as a reciprocating direction of the movable mold) in which the movable mold 1 is in close contact with and spaced from the movable mold 1. [ The movable mold 2 is provided with a plurality of through holes 2a extending in the reciprocating direction A of the movable mold 1. When the movable mold 2 is in close contact with the stationary mold 1, The cavity 3 is formed. The eject plate 4 is arranged so as to oppose the back surface of the movable mold 2 (that is, the surface opposite to the surface on which the cavity 3 is formed), and a hydraulic mechanism (not shown) And can be moved forward or backward with respect to the movable mold 2 together with the rod 9 when the rod 9 is reciprocatingly moved. The ejection pins 5 move forward together with the eject plate 4 when the eject plate 4 advances toward the movable mold 2 to move the metal product molded in the cavity 3 to the movable mold 2 ). Each of the eject pins 5 is slidably inserted into the through hole 2a of the movable mold 2 and one end thereof is fixed to the eject plate 4. [
An enclosure 100 is provided on the back side of the movable mold 2 so as to form a closed space 8 surrounding the ejection plate 4 and one ends of the ejection pins 5. As a vacuum means for sucking the gas in the cavity 3 and the closed space 8 by vacuum pressure and discharging the gas to the outside, the vacuum state is maintained by the vacuum pump P1, 3 and a vacuum tank T2 which is held in a vacuum state by a vacuum pump P2 and connected to the closed space 8 by a flow path R2. The flow path R1 is provided with a valve V1 for opening and closing the flow path R1 and the flow path R2 is provided with a valve V2 for opening and closing the flow path R2.
On the other hand, the surrounding structure of the enclosure 100 and the enclosure 100 has a different structure from the enclosure 7 or the like of the die casting mold apparatus 1A described with reference to Figs. This will be described in more detail as follows.
The enclosure 100 includes a hermetically sealed body 110 and a container member 120. The hermetically sealed body 110 is a member constituting the upper portion of the enclosure 100 and has a cylindrical shape with a surface facing the movable mold 2. [ The hermetically sealed main body 110 is tightly coupled to the back surface of the movable mold 2 by a suitable fixing means such as a screw (not shown) The ends of the. A liquid passage hole 111 is formed at the bottom of the hermetically sealed body 110 so as to penetrate the inner and outer surfaces of the hermetically sealed body 110 in the vertical direction. The inner bottom surface 115 of the hermetically closed body 110 is inclined in a direction to be lowered toward the liquid passing hole 111. The inner bottom surface 115 of the hermetically closed body 110,
The container member 120 is a member constituting a lower portion of the enclosure 100 and is formed in a cylindrical shape that opens upward. The container member 120 is made of a transparent material (for example, a transparent glass, ). The container member 120 has a flange portion 121 formed on the entire periphery of the upper rim and an upper open portion is located below the liquid passage hole 111 of the enclosure 110, (Not shown). The container member 120 is fixed to the sealing body 110 by a fixing member 130. The fixing member 130 is a member fixed to the sealing body 110 by screws 139 in a state in which the flange portion 121 of the container member 120 is pressed toward the sealing body 110 from below. The inner space of the container member 120 communicates with the inner space of the enclosure 110 through the liquid passage hole 111 of the enclosure 110. The inner space of the closed main body 110 and the inner space of the container member 120 form a closed space, i.e., the closed space 8.
A discharge port 125 for communicating the closed space 8 to the outside is formed at the bottom of the container member 120 (i.e., the bottom of the enclosure 110). This discharge port 125 flows into the closed space 8 through the through holes 2a of the movable mold 2 and flows into the closed space 8 through a mold releasing agent, water, etc. Liquid "in some cases) to the outside of the enclosure 100. [
A display portion 126 for indicating the predetermined level is formed on one side wall of the container member 120 so that the liquid that has been accumulated in the closed space 8 can visually be determined whether or not the liquid reaches a predetermined level. Therefore, the operator can visually confirm whether the upper surface of the liquid which is accumulated in the container member 120 and the display portion 126 are at the same height, so that whether or not the liquid level reaches the predetermined level can be known. The specific value of the 'preset water level' may be set differently depending on the volume of the closed space 8, the shape of the cavity 3, and the like. For example, A water level which is not likely to be discharged to the side of the vacuum tank T2 but is likely to be partially introduced into the cavity 3 through the through holes 2a is calculated and measured in advance and the water level at that time is referred to as the " .
The inner space of the container member 120 is formed so that the width in the reciprocating direction A of the movable mold and the width in the horizontal direction perpendicular to the reciprocating direction of the movable mold are both narrowed downward. The inner bottom surface 126 of the container member 120 is inclined in a direction in which the inner bottom surface 126 of the container member 120 is lowered toward the outlet 125.
A sealing member 129 is provided between the hermetically sealed body 110 and the container member 120. The sealing member 129 is formed into a quadrangular ring shape by an elastic rubber material such as silicone rubber and elastically contacts the hermetically sealed body 110 and the container member 120, And sealing is performed between the members 120. If the groove portion 128 for receiving the lower portion of the sealing member 129 is formed on the upper surface of the flange portion 121 of the container member 120, the sealing member 110, the container member 120, The lower end of the sealing member 129 is accommodated in the groove portion 128 of the container member 120 so that the sealing member 129 is brought into contact with the container member 120 Since the sealing member 110 and the container member 120 are combined with each other in a fixed position, the operation for forming the sealing member 100 can be easily performed.
The discharge port 125 of the container member 120 is provided with a first valve 101 for opening and closing the discharge port 125. The discharge port 125 is connected to the vacuum tank (T3). The connection pipe unit 140 includes a first connection pipe 141 having one end connected to the discharge port 125 via the first valve 101 and a second connection pipe 141 having one end connected to the discharge port 125 via the second valve 102, A second connection pipe 142 connected to the other end of the second connection pipe 142 and the other end of the first connection pipe 141 so as to be connected to the first connection pipe 141 and the second connection pipe 142, And a reservoir tank 145 for communicating the two connection pipes 142 with each other. The discharge port 125 and the liquid discharge vacuum tank T3 communicate with each other through the connection pipe unit 140 when the first valve 101 and the second valve 102 are opened and the vacuum suction force Is applied to the liquid in the closed space (8). The reservoir tank 145 has an internal space in which the introduced liquid is stored, and is made of a transparent material (for example, transparent synthetic resin such as transparent glass or transparent acrylic) so that the internal space can be seen.
A lower portion of the storage tank 145 is connected to the lower portion of the reservoir tank 145 through an outlet 125 to discharge the liquid that is discharged from the closed space 8 into the storage tank 145 along the first connection pipe 141, A discharge port 150 and a third valve 103 for opening and closing the auxiliary discharge port 150 are provided. If the volume of the storage tank is too large, the vacuum suction force by the liquid discharge tank T3 for the liquid in the closed space 8 must be reduced or the liquid discharge tank T3 must be enlarged. Therefore, it is preferable that the volume of the storage tank is set to about 2 to 3 times (that is, the capacity of 2 to 3 times of liquid discharge) of the liquid in the closed space 8 when reaching the predetermined water level.
A sensor 160 is installed in the enclosure 100. The sensor 160 may be a pressure sensor that detects the pressure in the enclosure 100, that is, the pressure in the closed space 8, or may be a water level sensor that detects the level of the liquid that is accumulated in the closed space 8. As the water level sensor, for example, a well-known capacitive water level sensor, a float type water level sensor, or an electric conductivity type (electrode type) water level sensor can be used.
In the present embodiment, the sensor 160 uses a water level sensor for detecting the level of the liquid which is pumped into the closed space 8, and the first valve 101 and the second valve 102 are constituted by solenoid valves , As shown in Fig. 8, the control section 105 that receives a signal from the sensor 160 is configured to control opening and closing of the valves 101 and 102, respectively. Specifically, when the sensor 160 detects that the level of the liquid which has been accumulated in the closed space 8 has reached the predetermined level (preset value), a signal corresponding thereto is transmitted to the control unit 105, The controller 105 opens the first valve 101 and the second valve 102 based on the signal received from the sensor 160 to thereby open the flow path between the discharge port 125 and the liquid discharge vacuum tank T3 The first connection pipe 141, the storage tank 145, and the second connection pipe 142). Then, after the first valve 101 and the second valve 102 are opened as described above, a predetermined time (for example, a time period from the time when the liquid, which is accumulated in the closed space 8, The controller 105 controls the first valve 101 and the second valve 102 to close again so that the outlet 125 and the liquid discharge And the vacuum tank T3.
On the other hand, according to the study by the present inventor regarding the 'preset water level', a metal product (for example, aluminum front pillar (also referred to as "A filler") or shock absorber case In the case of a die apparatus for die-casting a shock-absorber case (for example, an aluminum product requiring high tensile, yield strength, elongation, and welding with other components), the amount of liquid, When the volume of the entire ejector plate 8 exceeds the value obtained by subtracting the volume of the ejection plate 4 from the volume of the space enclosed by the enclosure 100 and the movable mold 2, The mold releasing agent or moisture vaporized in the vacuum tank T2 can not be discharged to the side of the vacuum tank T2, and a part of the mold releasing agent or moisture is likely to flow into the cavity 3 through the through holes 2a. Therefore, when diecasting the aluminum front pillar or shock absorber case for automobiles, the amount of the liquid in the closed space 8 is set to 5, which is a value obtained by subtracting the volume of the ejection plate 4 from the volume of the entire closed space 8 (When the water level at this time reaches the predetermined water level), the sensor 160 detects the water level and sends a signal to the control unit 105.
Although not shown, there is a gap (not shown) between the enclosure 100 and the member coupled to the enclosure 100, such as between the enclosure 100 and the movable mold 2, between the enclosure 100 and the rod 9, An appropriate sealing member such as a rubber ring or the like may be provided to prevent the gap.
The basic function of the high vacuum die casting mold apparatus 10 having such a configuration is the same as that of the conventional die casting mold apparatus 1A described above. That is, in the case of the high vacuum die casting mold apparatus 10 of the present embodiment, after the movable mold 2 is brought into close contact with the stationary mold 1, the molten metal M1 is injected into the cavity 3 by the injection cylinder 15 When the predetermined time has elapsed, the molten metal in the cavity 3 hardens and becomes a metal product having a shape corresponding to the cavity 3. When the movable mold 2 is spaced apart from the stationary mold 1 and the rod 9 and the ejection plate 4 move forward with respect to the movable mold 2 so that the ejection pins 5 can move the metal product The movable mold 2 is brought into close contact with the stationary mold 1 and the ejection plate 4 is retreated after the movable mold 2 is pushed out of the mold 2 and separated and the mold surface of each of the molds 1 and 2 is appropriately sprayed with the mold release agent . Thereafter, the molten metal is injected into the cavity 3 again, and the metal product molding process as described above is repeated.
On the other hand, before the movable mold 2 is brought into close contact with the stationary mold 1 and the molten metal M1 is injected into the cavity 3 by the injection cylinder 15, the valve V2 is opened and the vacuum pump P2 The gas in the closed space 8 is sucked toward the vacuum tank T2 along the flow path R2 by the vacuum pressure in the vacuum tank T2. The valve V1 is opened so that the gas in the cavity 3 is sucked toward the vacuum tank T1 along the flow path R1 by the vacuum pressure in the vacuum tank T1 by the vacuum pump P1, . The gas in the closed space 8 is sucked by the vacuum tank T2 in advance and discharged to the outside and the gas in the cavity 3 is discharged from the cavity 3 to the outside by the vacuum tank T1, 3), it is prevented that the gas is mixed into the molten metal.
The vacuum degree of vacuum formed in the cavity 3 as the gas in the cavity 3 is sucked by the vacuum tank T1 as described above and the vacuum degree of the vacuum formed in the cavity 3 by the vacuum tank T2 , The degree of vacuum in the cavity 3 is maintained at a higher level than 40 Torr when the front filler made of aluminum for automobile or the shock absorber case is die-cast in relation to the degree of vacuum formed in the closed space 8, It is preferable to maintain the degree of vacuum in the chamber 8 at 400 to 200 Torr. If the degree of vacuum in the cavity 3 is lower than 40 Torr, there is a possibility that the above-mentioned effect of preventing the gas from mixing is remarkably reduced. When the degree of vacuum in the closed space 8 becomes lower than 400 Torr, the gas in the closed space 8 flows through the gap between the ejection pins 5 and the movable mold 2 by the degree of vacuum in the cavity 3 It is difficult to effectively prevent the vacuum tank T2 from being introduced into the cavity 3. When the degree of vacuum in the closed space 8 becomes higher than 200 Torr, the possibility of unnecessarily increasing the capacity of the vacuum tank T2 is increased. For reference, the larger the capacity of a vacuum tank, the more expensive it is, and even if the capacity is slightly increased, the cost will increase significantly. Therefore, even if the capacity of the vacuum tank can be reduced to a small extent, the purchase cost of the vacuum tank can be greatly reduced.
As the valve V2 is opened and the closed space 8 is evacuated as described above, it is possible to prevent the liquid from being poured from the side of the cavity 3 during the production of the metal products while continuing the die- The sensor 160 detects the level of the liquid such as a mold releasing agent or moisture that has flowed into the closed space 8 through the hole 2a gradually increases to reach the predetermined value, A signal indicating that the water level has reached the predetermined value is sent. The control unit 105 receiving the signal from the sensor 160 opens the first valve 101 and the second valve 102 to open the flow path between the discharge port 125 and the liquid discharge vacuum tank T3, The flow path inside the connector unit 140 is opened. The liquid held in the closed space 8 is discharged to the closed space 8 through the discharge port 125 by the vacuum pressure in the liquid discharge vacuum tank T3 by the vacuum pump P3 and the self- And is discharged to the side of the vacuum tank T3 for liquid discharge along the first connection pipe 141. [ The liquid discharged to the side of the vacuum tank T3 for liquid discharge along the first connection pipe 141 flows into the reservoir tank 145 and starts to accumulate in the reservoir tank 145. [ The vacuum pressure of the vacuum tank T3 for discharging the liquid is maintained even when the liquid is accumulated in the reservoir tank 145 by the second connection pipe 142, the reservoir tank 145, the first connection pipe 141, Through the outlet 125, from the enclosed space 8 and from the enclosed space 8, as shown in FIG.
The control unit 105 performs control to close the first valve 101 and the second valve 102 after the first and second valves 101 and 102 have been opened for a predetermined period of time, And closes the flow path between the discharge port 125 and the liquid discharge vacuum tank T3. When this process is completed, all of the liquid discharged from the closed space 8 is stored in the reservoir tank 145. The liquid in the closed space 8 is discharged through the discharge port 125 and the first connection pipe 141 and is stored in the storage tank 145 and discharged through the discharge port 125 and the liquid discharge vacuum tank T3, , The third valve (103) is opened to open the auxiliary discharge port (150). Then, the liquid stored in the reservoir tank 145 is discharged to the outside of the reservoir tank 145 through the auxiliary discharge port 150. When all of the liquid in the reservoir tank 145 is discharged, the third valve 103 is closed again. For reference, the opening and closing of the third valve 103 as described above may be performed manually by the die casting operator, or may be performed based on, for example, a command from the control section 105. [
As described above, in the high vacuum die casting mold apparatus 10 of the present embodiment, when the liquid in the closed space 8 reaches the " preset water level ", the liquid is discharged through the liquid discharge path It is possible to effectively prevent a part of the liquid vaporized in the closed space 8 from flowing into the cavity 2 through the through holes 2a.
Meanwhile, in the present embodiment, the inner bottom surface 115 of the sealed body 110 is formed to be inclined in a direction to be lowered toward the liquid passing hole 111. Therefore, the liquid such as the releasing agent introduced from the cavity 3 side can flow into the container member 120 through the liquid passage hole 111 easily without staying on the bottom surface of the enclosure 110 . The inner space of the container member 120 is formed so that both the width of the movable mold in the reciprocating direction A and the width in the horizontal direction perpendicular to the reciprocating direction A of the movable mold become narrower And the inner bottom surface 127 of the container member 120 is formed to be inclined in a direction to be lowered toward the discharge port 125. [ Therefore, when the liquid which has been accumulated in the enclosure 100 is discharged through the discharge port 125, the liquid does not remain on the bottom surface of the container member 120 or remains in the dead state, And can be discharged to the outside through the outlet 125.
As in the present embodiment, if the portion where the liquid is held in the enclosure 100 (the container member 120 in the present embodiment) is formed transparently, the level of the liquid that has been poured can be easily confirmed by the naked eye of the operator, If the display unit 126 for displaying the predetermined water level is formed in the container member 120, whether or not the liquid accumulated in the current enclosure 100 reaches the predetermined water level can be easily confirmed in advance by the operator's eyes . Therefore, it is convenient that the die-casting operator can directly open the discharge port 125 by operating the first valve 101 when necessary. Further, when the reservoir tank 145 is formed of a transparent material, it is easy to visually check the degree of liquid stored in the reservoir tank 145 by the naked eye of the diecasting operator, So that the auxiliary outlet 150 can be opened. When the liquid discharge vacuum tank T3 for applying a vacuum suction force to the liquid through the discharge port 125 is provided in a capacity larger than that of the vacuum tank T2 for discharging the gas in the closed space 8, Even when the vacuum pressure in the sealed space 8 is applied to the sealed space 8, the liquid in the sealed space 8 can be easily sucked and discharged through the discharge port 125, which is convenient.
Although the liquid discharge vacuum tank T3 is described separately from the vacuum tank T2 for discharging the gas in the closed space 8 in the above embodiment, The tank T2 may also be used as a liquid tank for discharging liquid (a vacuum tank for applying a vacuum suction force to the liquid through the discharge port 125) in the present invention. That is, the second connection pipe 142 of the connection pipe unit 140 is connected to the vacuum tank T2 without being connected to the liquid discharge vacuum tank T3, And a vacuum tank for discharging gas in the closed space.
Although the sensor 160 is described as being a water level sensor, it is also possible to use a pressure sensor for detecting the pressure in the closed space 8. In this case, the pressure in the closed space 8 increases as the vaporization amount of the liquid held in the closed space 8 increases, so that the pressure in the closed space 8 is maintained at the predetermined level (that is, the closed space 8 ), And a pressure value at a time when the vaporized mold release agent or moisture is not discharged to the side of the vacuum tank T2 but a part of the gas is likely to flow into the cavity 3 through the through holes 2a The sensor 160 detects this and sends a signal to the control unit 105. [0064] For example, in the case of die-casting aluminum front pillar or shock absorber case for automobile, the pressure of the closed space at the time when the amount of the liquid in the closed space becomes 5% of the value obtained by subtracting the volume of the ejection plate from the volume of the closed space When the pressure becomes higher, it is preferable that a signal is sent from the sensor 160 to the control unit 105.
In the present embodiment, the entire reservoir tank 145 is described as being transparent. However, only a part of the reservoir tank 145 (for example, only one wall portion) may be made transparent as long as the amount of liquid in the reservoir can be visually confirmed. Similarly, only a part of the container member 120 (for example, only one wall portion) may be made transparent, as long as the inside of the container member 120 is transparent.
In the present embodiment, the first and second valves 101 and 102 are constituted by solenoid valves, and the connection pipe unit 140 and the liquid discharge vacuum tank T3 are provided. However, the connection pipe unit 140, the vacuum tank T3 for liquid discharge and the second valve 102 may not be provided. That is, for example, when the sensor 160 generates a signal indicating that the pressure in the closed space 8 or the liquid level in the closed space 8 has reached a preset value, The liquid in the closed space 8 is discharged to the outside of the closed space 8 through the discharge port 125 by gravity (self weight) by opening the discharge port 101 by opening the discharge port 125. Alternatively, 1 valve 101 is constituted by a ball valve which can be manually operated by a die-casting operator, and at the appropriate time (for example, when the upper surface of the liquid in the closed space 8 reaches the display portion 126) , The die casting operator manually operates the ball valve (first valve) to open the discharge port 125 to discharge the liquid in the closed space 8 to the outside by gravity (the weight of the liquid) . At this time, it is preferable that the opening of the discharge port 125 as described above is performed when the movable mold 2 is moved to a position spaced apart from the stationary mold 1. When the movable mold 2 is moved in the fixed mold 1, It is preferable to provide a container (not shown) for receiving the liquid discharged to the outside of the closed space 8 through the discharge port 125 below the discharge port 1 at a position spaced apart from the discharge port 1. However, in the case where the liquid is discharged through the discharge port 125 by the self weight of the liquid without providing the liquid discharge vacuum tank T3, the connection pipe unit 140, or the like, The liquid may not be easily discharged to the discharge port 125 even if the first valve 101 is opened due to the vacuum pressure if the vacuum pressure generated by the vacuum pump T2 is applied to the closed space 8. Therefore, It is necessary to open the first valve 101 after the valve V2 is closed so that the vacuum pressure of the vacuum tank T2 does not act on the closed space 8 and therefore it may be troublesome compared with the embodiment described above .
While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
