JP5087999B2 - Vacuum die casting apparatus and vacuum die casting method - Google Patents

Description

  The present invention relates to a vacuum die casting apparatus and a vacuum die casting method.

In vacuum die casting, after the mold is clamped, the inside of the cavity of the mold is decompressed so that the molten metal is supplied from the holding furnace to the inside of the cavity via the hot water supply pipe and the injection means (for example, patents). Reference 1).
Japanese Patent Laid-Open No. 2003-1391

  However, between the start of mold clamping and the completion of mold clamping, excess air inside the cavity flows back to the holding furnace via the injection means and the hot water supply pipe. Since air is at room temperature, peripheral equipment such as hot water pipes can be rapidly cooled by bringing the hot water pipes that have been heated up into contact with the molten metal inside the holding furnace to cause the molten metal to scatter. And has the problem of reducing the durability of the holding furnace.

  The present invention has been made in order to solve the problems associated with the above-described prior art, and an object thereof is to provide a vacuum die casting apparatus having good durability and a vacuum die casting method capable of improving the durability of the vacuum die casting apparatus. And

In order to achieve the above object, the invention described in claim 1
First and second molds having cavities corresponding to the outer shape of the molded product,
Mold clamping means for clamping the first and second molds;
Injection means for injecting molten metal constituting the molded product into the cavity;
A holding furnace holding the molten metal,
A hot water supply pipe for introducing the molten metal of the holding furnace into the injection means ,
Before the mold clamping is completed, auxiliary air is sucked into the cavity to prevent the air from flowing back to the hot water supply pipe and the holding furnace via the injection means, and the mold clamping is completed. A decompression means for supplying the molten metal of the holding furnace to the injection means via the hot water supply pipe by main suction of the air inside the cavity , and
Control means for controlling the decompression means;
In the vacuum die casting apparatus, the control means controls the decompression means so that the molten metal in the holding furnace is not supplied to the injection means via the hot water supply pipe during auxiliary suction. .

In order to achieve the above object, the invention according to claim 7 provides:
Before the clamping of the first and second molds having cavities corresponding to the outer shape of the molded product is completed, the air inside the cavity is auxiliary sucked so that the air forms the molten metal constituting the molded product. Suppressing back flow to the hot water supply pipe for introducing the molten metal into the injection means and the holding furnace holding the molten metal via the injection means for injecting into the cavity,
After the completion of mold clamping, the main suction of the air inside the cavity supplies the molten metal of the holding furnace to the injection means via the hot water supply pipe ,
The auxiliary suction is a vacuum die casting method that is controlled so that the molten metal in the holding furnace is not supplied to the injection means via the hot water supply pipe .

According to the first aspect of the present invention, the air flows back to the hot water supply pipe and the holding furnace by the auxiliary suction of the air inside the cavities of the first and second molds by the decompression means before the mold clamping is completed. that, Ri can der be suppressed, and, by the control means, when the auxiliary suction, the molten metal holding furnace, so as not to be fed to an injection unit through a hot water supply pipe, the pressure reducing means is controlled The Therefore, the hot water supply pipe that has been heated is rapidly cooled by the back-flowing normal temperature air, or when it is brought into contact with the molten metal inside the holding furnace, it rapidly expands and the molten metal is scattered. Decreasing the durability of the peripheral equipment and holding furnace is avoided. That is, a vacuum die casting apparatus having good durability can be provided.

According to the seventh aspect of the present invention, the auxiliary suction before the completion of mold clamping suppresses the air inside the cavities of the first and second molds from flowing back to the hot water supply pipe and the holding furnace , and , the auxiliary suction, the molten metal holding furnace, that are controlled so as not to be fed to an injection unit through a hot water supply pipe. Therefore, the hot water supply pipe that has been heated is rapidly cooled by the back-flowing normal temperature air, or when it is brought into contact with the molten metal inside the holding furnace, it rapidly expands and the molten metal is scattered. Decreasing the durability of the peripheral equipment and holding furnace is avoided. That is, it is possible to provide a vacuum die casting method that can improve the durability of the vacuum die casting apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a partially broken perspective view for explaining a vacuum die casting apparatus according to the first embodiment, and FIG. 2 is a graph for explaining auxiliary suction according to the first embodiment.

  The vacuum die casting apparatus 100 includes a fixed mold (first mold) 110, a movable mold (second mold) 115, a mold clamping means 120, an injection means 130, a holding furnace 140, a hot water supply pipe 150, a pressure reducing means 160, and a control means 180. Have

  The fixed mold 110 and the movable mold 115 have cavities 111 and 116 corresponding to the outer shape of the molded product, and are detachably fixed to the platens 113 and 118. The molded article is, for example, an automobile body part or a suspension part. The vehicle body parts are, for example, joints of pillars, roofs, and space frames. The suspension parts are a suspension arm, a subframe, a suspension link part, and an engine cradle. The molten metal M injected into the cavities 111 and 116 is, for example, an aluminum alloy. An aluminum alloy is preferable in terms of weight reduction of the vehicle.

  The mold clamping means 120 is used for clamping the fixed mold 110 and the movable mold 115, and has reciprocating means for driving the movable mold 115 toward and away from the fixed mold 110. The reciprocating means is composed of, for example, a hydraulic cylinder, and is connected to a platen 118 that fixes the movable die 115.

  The injection means 130 is used for injecting the molten metal M constituting the molded product into the cavities 111 and 116, and includes an injection sleeve 132, an injection tip 134, a piston rod 136, and a vacuum chamber 138.

  The injection sleeve 132 is supported by the platen 113 to which the fixed mold 110 is fixed, and its tip 133 communicates with the cavity 111 of the fixed mold 110 to temporarily hold the molten metal M constituting the molded product. Used to do. The injection tip 134 is inserted into the injection sleeve 132 so as to be movable forward and backward. A clearance of, for example, about 0.05 to 0.5 mm is secured between the injection tip 134 and the injection sleeve 132 in consideration of thermal expansion and the like.

  The piston rod 136 has a smaller diameter than the injection tip 134, is fixed to the rear of the injection tip 134, and is driven by reciprocating means (not shown). Therefore, when the piston rod 136 is moved forward, the injection tip 134 moves forward toward the cavity 111 of the fixed mold 110 inside the injection sleeve 132. Therefore, the molten metal M held by the injection sleeve 132 is transferred to the cavities 111, 111. It is possible to inject inside 116. It is also preferable to form a coolant channel inside the injection tip 134 and the piston rod 136 to forcibly cool the injection tip 134.

  The vacuum chamber 138 is concentrically disposed at the rear end portion of the injection sleeve 132 and is connected to a piping system (not shown) extending from the decompression means 160, and the injection sleeve 132 at the time of injection of the molten metal M is provided. It is used to relax the thermal conditions of the rear end portion and the seal member (not shown).

  Thereby, a stable vacuum state can be maintained by applying a sealing member having a relatively low heat resistance but having a good sealing property, for example, a rubber packing such as nitrile rubber or fluorine rubber. The capacity of the vacuum chamber 138 is preferably set as appropriate in consideration of the heat insulating effect, interference with peripheral devices, the time required for reducing the pressure, and the like.

  The holding furnace 140 has heating means 142 for maintaining the temperature of the molten metal M, and holds the molten metal M in a state in which it does not solidify. The heating means 142 is, for example, a heater. The temperature of the holding furnace 140 is, for example, 700 ° C. when the molten metal M is an aluminum alloy.

  The hot water supply pipe 150 has one end fixed to the rear end portion of the injection sleeve 132 and the other end reaching the inside of the molten metal M of the holding furnace 140, and the molten metal M of the holding furnace 140 is injected into the injection sleeve 132 (injection). Used to introduce to the means 130). On the outer periphery of the hot water supply pipe 150, heating means (not shown) for maintaining the temperature is arranged. Reference numeral 152 denotes a fixing jig for fixing one end of the hot water supply pipe 150 to the rear end portion of the injection sleeve 132, and includes, for example, a holding bracket and a set screw.

  The decompression means 160 includes a vacuum pump 162, a buffer vacuum tank 164, and a piping system 170. Before the mold clamping is completed, the air inside the cavities 111 and 116 is auxiliary sucked so that the air is injected into the injection sleeve 132. The hot water pipe 150 and the holding furnace 140 are prevented from flowing back to each other, and after the mold clamping is completed, the air inside the cavities 111 and 116 is finally sucked, whereby the molten metal M of the holding furnace 140 is Used to supply the injection sleeve 132 via the hot water supply pipe 150.

  Therefore, the hot water supply pipe that has been heated is rapidly cooled by the back-flowing normal temperature air, or when it is brought into contact with the molten metal inside the holding furnace, it rapidly expands and the molten metal is scattered. Decreasing the durability of the peripheral equipment and holding furnace is avoided.

  The vacuum pump 162 is not particularly limited. For example, the vacuum pump 162 is a reciprocating mechanical pump such as a piston pump or a rotary mechanical pump such as an oil rotary pump. The buffer vacuum tank 164 is disposed between the vacuum pump 162 and the piping system 170, and is used to maintain a stable vacuum state.

  The piping system 170 extends to the cavities 111 and 116 of the fixed mold 110 and the movable mold 115 in order to perform auxiliary suction and main suction of the air inside the cavities 111 and 116, and the pipe opening / closing means 172 and 174 are provided on the way. Is arranged. The pipe opening / closing means 172 is composed of, for example, an electromagnetic valve, and can release the pipe system 170 by releasing the connection (communication) with the vacuum pump 162 and the buffer vacuum tank 164. The pipe opening / closing means 174 is composed of, for example, a vacuum valve, and is disposed in the middle of the pipe between the pipe opening / closing means 172 and the cavities 111 and 116, and is located in the vicinity of the cavities 111 and 116.

  Therefore, by setting the pipe opening / closing means 172 and the pipe opening / closing means 174 to the “open” state, the buffer vacuum tank 164 communicates with the inside of the cavities 111, 116, and the air inside the cavities 111, 116 is assisted by suction. This suction is possible.

  The control means 180 controls the reciprocating means of the mold clamping means 120, the reciprocating means of the piston rod 136, the heating means 142 of the holding furnace 140, the heating means of the hot water supply pipe 150, the vacuum pump 162, and the pipe opening / closing means 172 and 174. Used for.

  In addition, the control unit 180 includes a timer unit 190 for detecting the elapsed time. The timer unit 190 is used to control the decompression unit 160 so that the molten metal M in the holding furnace 140 is not supplied to the injection sleeve 132 via the hot water supply pipe 150 during auxiliary suction. That is, the control unit 180 controls the decompression unit 160 to stop the auxiliary suction when the elapsed time detected by the timer unit 190 reaches a predetermined value.

  For example, as shown in FIG. 2, the internal pressures of the cavities 111 and 116 decrease in accordance with the elapsed time of the reduced pressure, and start the back flow of the molten metal and the suction of the molten metal according to the reached pressure. Therefore, as the predetermined value for controlling the decompression means 160, for example, an elapsed time until reaching a pressure slightly larger than the pressure causing the start of backflow of the molten metal can be applied. The elapsed time is detected with the start of mold clamping as a reference time.

  Next, the vacuum die casting method according to Embodiment 1 will be described.

  3 and 4 are a block diagram and a graph for explaining a control flow of the vacuum die casting apparatus shown in FIG.

  In the vacuum die casting method according to Embodiment 1, the vacuum pump 162 is operated in a state where the pipe opening / closing means 172 and 174 are set to “closed”. Then, the pipe opening / closing means 172 and 174 are sequentially set to “open”, and auxiliary decompression is started.

  By driving the platen 118 to which the movable mold 115 is fixed toward the fixed mold 110 by the reciprocating means of the mold clamping means 120, the movable mold 115 moves forward toward the fixed mold 110, and the mold clamping is started. The Further, the timer means 190 of the control means 180 starts with the start of mold clamping as a reference time, and starts detecting the elapsed time.

  At this time, air inside the cavities 111 and 116 of the fixed mold 110 and the movable mold 115 is auxiliary sucked by the auxiliary pressure reduction, so that the air passes through the injection sleeve 132 to the hot water supply pipe 150 and the holding furnace 140. Backflow is suppressed. Therefore, by rapidly cooling the hot water supply pipe 150 that has been heated by the backflowing normal temperature air, or by contacting with the molten metal M inside the holding furnace 140, it rapidly expands and the molten metal is scattered. Decreasing the durability of peripheral equipment such as the hot water supply pipe 150 and the holding furnace 140 can be avoided.

  When the elapsed time detected by the timer means 190 reaches a predetermined value, the pipe opening / closing means 174 is set to “closed” and the auxiliary decompression is stopped. Thereby, it is suppressed that the pressure inside the cavities 111 and 116 falls excessively. That is, the molten metal M in the holding furnace 140 is controlled so as not to be supplied to the injection sleeve 132 via the hot water supply pipe 150.

  When the movable mold 115 reaches the mold clamping limit and the mold clamping is completed, the pipe opening / closing means 174 is switched to “open”, and the main decompression is started. In the main decompression, the air inside the cavities 111 and 116 is sucked, whereby the suction of the molten metal M in the holding furnace 140 is started and introduced into the injection sleeve 132 via the hot water supply pipe 150.

  When the molten metal M inside the injection sleeve 132 reaches a predetermined amount for forming a molded product, the piston rod 136 is driven. The injection tip 134 disposed in front of the piston rod 136 injects the molten metal M toward the inside of the cavities 111 and 116, and a molded product is cast.

  FIG. 5 is a graph showing the relationship between the main pressure reduction elapsed time and the molten metal suction amount in the vacuum die casting apparatus shown in FIG. 1, FIG. 6 is a block diagram for explaining a control flow according to a comparative example, and FIG. These are the graphs which show the relationship between the pressure reduction elapsed time and the amount of molten metal suction in the comparative example. As shown in FIG. 6, the comparative example is substantially the same as the first embodiment except for the auxiliary pressure reduction (auxiliary suction).

  In the first embodiment, before the main pressure reduction, excess air inside the cavities 111 and 116 is removed by the auxiliary pressure reduction. Therefore, compared with the comparative example, it is possible to shorten the time required to reduce the pressure inside the cavities 111 and 116 and improve the cycle time (see FIGS. 5 and 7).

  As described above, the first embodiment can provide a vacuum die casting apparatus having good durability and a vacuum die casting method capable of improving the durability of the vacuum die casting apparatus.

  The elapsed time in the timer means 190 of the control means 180 is not limited to the form in which the mold clamping start is set as a reference time. Further, two series of decompression means 160 can be provided and can be made independent as the decompression means for auxiliary decompression and the decompression means for main decompression.

  FIG. 8 is a partially broken perspective view for explaining a vacuum die casting apparatus according to the second embodiment, FIG. 9 is a block diagram for explaining a control flow according to the second embodiment, and FIG. 2 is a graph for explaining auxiliary suction according to 2; In addition, about the member which has the function similar to Embodiment 1, the same code | symbol is used and in order to avoid duplication, the description is abbreviate | omitted.

  The second embodiment uses the elapsed time detected by the timer means 190 in that the stroke of the reciprocating means of the mold clamping means is used as a parameter applied to the control of the pressure reducing means at the time of auxiliary suction. Generally different from Form 1.

  More specifically, the vacuum die casting apparatus 200 includes a stroke detection unit 290 made up of, for example, a displacement sensor or a length measurement sensor. The stroke detection means 290 is disposed in the mold clamping means 220 and is used to detect the stroke of the reciprocating means for driving the movable mold 215 toward and away from the fixed mold 210.

  The detection value of the stroke detection means 290 is reduced so that the molten metal M in the holding furnace 240 is not supplied to the injection sleeve 232 (injection means 230) and the cavities 211 and 216 via the hot water supply pipe 250 during auxiliary suction. Used to control the means 260. That is, the control unit 280 controls the decompression unit 260 to stop the auxiliary suction when the stroke detected by the stroke detection unit 290 reaches a predetermined value.

  For example, as shown in FIG. 10, the pressure inside the cavities 211 and 216 decreases according to the stroke, and starts the back flow of the melt and the suction of the melt according to the reached pressure. Therefore, as the predetermined value for controlling the decompression means 260, for example, a stroke value that reaches a pressure slightly larger than the pressure that causes the start of backflow of the molten metal can be applied.

  Next, a vacuum die casting method according to Embodiment 2 will be described.

  The vacuum pump 262 is operated in a state where the pipe opening / closing means 272 and 274 are set to “closed”. Then, the pipe opening / closing means 272 and 274 are sequentially set to “open”, and auxiliary decompression is started.

  By driving the platen 218 to which the movable mold 215 is fixed toward the fixed mold 210 by the reciprocating means of the mold clamping means 220, the movable mold 215 advances toward the fixed mold 210, and mold clamping is started. The Further, the stroke detecting means 290 arranged in the mold clamping means 220 starts detecting the stroke of the reciprocating means of the mold clamping means 220.

  At this time, the air in the cavities 211 and 216 of the fixed mold 210 and the movable mold 215 is auxiliary sucked by the auxiliary pressure reduction, so that the air enters the hot water supply pipe 250 and the holding furnace 240 via the injection sleeve 232. Backflow is suppressed.

  When the stroke detected by the stroke detection means 290 reaches a predetermined value, the pipe opening / closing means 274 is controlled to be set to “closed” and the auxiliary pressure reduction is stopped. Thereby, the pressure inside the cavities 211 and 216 is controlled so as not to decrease excessively. That is, the molten metal M in the holding furnace 240 is controlled so as not to be supplied into the injection sleeve 232 and the cavities 211 and 216 via the hot water supply pipe 250.

  When the movable mold 215 reaches the mold clamping limit and the mold clamping is completed, the pipe opening / closing means 274 is switched to “open”, and the main decompression is started. In the main decompression, the air inside the cavities 211 and 216 is sucked, whereby the suction of the molten metal M in the holding furnace 240 is started and introduced into the injection sleeve 232 through the hot water supply pipe 250.

  When the molten metal M inside the injection sleeve 232 reaches a predetermined amount for forming a molded product, the piston rod 236 is driven. The injection tip 234 disposed in front of the piston rod 236 injects the molten metal M toward the inside of the cavities 211 and 216, and a molded product is cast.

  Reference numerals 238, 242, 264, and 270 indicate a vacuum chamber, a heating means, a buffer vacuum tank, and a piping system.

  As described above, the second embodiment can apply the stroke of the reciprocating means of the mold clamping means 220 as a parameter applied to the control of the decompression means at the time of auxiliary suction.

  FIG. 11 is a partially broken perspective view for explaining a vacuum die casting apparatus according to Embodiment 3, and FIG. 12 is a block diagram for explaining a control flow of the vacuum die casting apparatus shown in FIG.

  The third embodiment is different from the first embodiment in which the elapsed time detected by the timer means 190 is used as a parameter applied to the control of the decompression means at the time of auxiliary suction in that the pressure inside the cavity is used. Generally different.

  More specifically, the vacuum die casting apparatus 300 includes pressure detection means 390 for detecting the pressure inside the cavities 311 and 316 of the fixed mold 310 and the movable mold 315. The pressure detection means 390 is, for example, a capacitance type vacuum sensor or pressure sensor, and is disposed in the middle of the piping between the piping opening / closing means 372 and the piping opening / closing means 374 in the piping system 370 of the decompression means 360, and It is located in the vicinity of the pipe opening / closing means 374.

  The detection value of the pressure detection means 390 is reduced so that the molten metal M in the holding furnace 340 is not supplied to the injection sleeve 332 (injection means 330) and the cavities 311 and 316 via the hot water supply pipe 250 during auxiliary suction. Used to control means 360. That is, the control unit 380 controls the decompression unit 360 to stop the auxiliary suction when the pressure detected by the pressure detection unit 390 reaches a predetermined value.

  As shown in FIG. 2 according to the first embodiment, the pressure inside the cavities 311 and 316 causes the molten metal to start back flow and the molten metal to start sucking according to the reached value. Therefore, it is possible to directly apply a pressure value slightly larger than the pressure causing the start of the back flow of the molten metal as the predetermined value for controlling the decompression means 360.

  Next, a vacuum die casting method according to Embodiment 3 will be described.

  The vacuum pump 362 is operated in a state where the pipe opening / closing means 372 and 374 are set to “closed”. Then, the pipe opening / closing means 372 and 374 are sequentially set to “open”, and auxiliary decompression is started.

  By driving the platen 318 to which the movable mold 315 is fixed toward the fixed mold 310 by the reciprocating means of the mold clamping means 320, the movable mold 315 moves forward toward the fixed mold 310, and mold clamping is started. The Further, the pressure detection means 390 disposed in the piping system 370 of the decompression means 360 starts detecting the pressure inside the cavities 311 and 316.

  At this time, the air inside the cavities 311 and 316 is auxiliary sucked by the auxiliary pressure reduction, so that the air is prevented from flowing back to the hot water supply pipe 350 and the holding furnace 340 via the injection sleeve 332.

  When the pressure detected by the pressure detection means 390 reaches a predetermined value, the pipe opening / closing means 374 is set to “closed” and the auxiliary pressure reduction is stopped. Thereby, the internal pressure of the cavities 311 and 316 is controlled so as not to decrease excessively. That is, the molten metal M of the holding furnace 340 is controlled so as not to be supplied into the injection sleeve 332 and the cavities 311 and 316 via the hot water supply pipe 350.

  Then, when the movable mold 315 reaches the mold clamping limit and the mold clamping is completed, the pipe opening / closing means 374 is switched to “open” and the main decompression is started. In the main decompression, the air inside the cavities 311 and 316 is sucked, whereby the suction of the molten metal M in the holding furnace 340 is started and introduced into the injection sleeve 332 via the hot water supply pipe 350.

  When the molten metal M inside the injection sleeve 332 reaches a predetermined amount for forming a molded product, the piston rod 336 is driven. The injection tip 334 disposed in front of the piston rod 336 injects the molten metal M toward the inside of the cavities 311 and 316, and a molded product is cast.

  Reference numerals 338, 342, and 364 denote a vacuum chamber, heating means, and a buffer vacuum tank.

  As described above, the third embodiment can apply the pressure inside the cavity as a parameter applied to control of the decompression means during auxiliary suction.

  Note that the pressure detection means 390 is not limited to being disposed in the middle of the pipe between the pipe opening / closing means 372 and the pipe opening / closing means 374. For example, a recess is formed in one of the cavities 311 and 316, and It is also possible to arrange.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, the parameters for controlling the pressure reducing means at the time of auxiliary suction are not limited to the elapsed time detected by the timer means, the stroke of the reciprocating means of the mold clamping means, and the pressure inside the cavity. It is also possible to use the distance between the (first mold) and the movable mold (second mold).

It is a partially broken perspective view for demonstrating the vacuum die-casting apparatus which concerns on Embodiment 1. FIG. 4 is a graph for explaining auxiliary suction according to the first embodiment. It is a block diagram for demonstrating the control flow of the vacuum die-casting apparatus shown by FIG. It is a graph for demonstrating the control flow of the vacuum die-casting apparatus shown by FIG. It is a graph which shows the relationship between this pressure reduction elapsed time and molten metal suction | attraction amount in the vacuum die-casting apparatus shown by FIG. It is a block diagram for demonstrating the control flow which concerns on a comparative example. It is a graph which shows the relationship between the pressure reduction elapsed time in a comparative example, and molten metal suction | attraction amount. It is a partially broken perspective view for demonstrating the vacuum die-casting apparatus which concerns on Embodiment 2. FIG. It is a block diagram for demonstrating the control flow of the vacuum die-casting apparatus which concerns on Embodiment 2. FIG. 10 is a graph for explaining auxiliary suction according to the second embodiment. It is a partially broken perspective view for demonstrating the vacuum die-casting apparatus which concerns on Embodiment 3. FIG. It is a block diagram for demonstrating the control flow of the vacuum die-casting apparatus shown by FIG.

Explanation of symbols

100 ... Vacuum die casting equipment,
110 .. Fixed type,
111.cavity,
113 .. Platen,
115 .. Movable type,
116 .. cavity
118. Platen,
120 .. Clamping means,
130 .. Injection means,
132 .. Injection sleeve,
133 ... tip
134 .. Injection chip,
136 .. piston rod,
138 ..Vacuum chamber
140 .. Holding furnace,
142 .. heating means,
150 .. Hot water supply pipe,
152 .. Heating means,
152 .. Fixing jig,
160 .. decompression means,
162 ... Vacuum pump,
164 ... Buffer vacuum tank,
170 ... Piping system
172, 174 .. Pipe opening / closing means,
180 .. Control means,
190..Timer means,
200 ... Vacuum die casting equipment,
210 .. Fixed type,
211 .. cavity
215 .. Movable type,
216 .. cavity,
218 Platen,
220 .. Clamping means,
230..Injection means,
232 .. Injection sleeve,
234 .. Injection chip,
236 .. Piston rod,
238 .. Vacuum chamber,
240 .. Holding furnace,
242, heating means,
250 .. Hot water supply pipe,
260 .. decompression means,
262 ... Vacuum pump,
H.264 ... Buffer vacuum tank,
270 ... Piping system
272, 274 .. Pipe opening and closing means,
280 .. Control means,
290 .. Stroke detection means,
300 ... Vacuum die casting equipment,
310 .. Fixed type,
311 ... cavity,
315 .. Movable type,
316 .. cavity,
318 platen,
320 .. Clamping means,
330..Injection means,
332 .. Injection sleeve,
334 .. Injection chip,
336 .. piston rod,
338 .. Vacuum chamber,
340 ... Holding furnace,
342 .. Heating means,
350 ... hot water supply pipe,
360 .. decompression means,
362 ・ ・ Vacuum pump
364-Buffer vacuum tank,
370 ... Piping system
372, 374 .. Pipe opening and closing means,
380 .. Control means,
390 .. Pressure detection means,
M ... molten metal.

Claims (12)

First and second molds having cavities corresponding to the outer shape of the molded product,
Mold clamping means for clamping the first and second molds;
Injection means for injecting molten metal constituting the molded product into the cavity;
A holding furnace holding the molten metal,
A hot water supply pipe for introducing the molten metal of the holding furnace into the injection means ,
Before the mold clamping is completed, auxiliary air is sucked into the cavity to prevent the air from flowing back to the hot water supply pipe and the holding furnace via the injection means, and the mold clamping is completed. A decompression means for supplying the molten metal of the holding furnace to the injection means via the hot water supply pipe by main suction of the air inside the cavity , and
Control means for controlling the decompression means;
The vacuum die casting apparatus characterized in that the control means controls the decompression means so that the molten metal in the holding furnace is not supplied to the injection means via the hot water supply pipe during auxiliary suction . The control means stops the auxiliary suction immediately before the completion of mold clamping, and controls the pressure reducing means so that a decrease in pressure inside the cavity is suppressed.
The vacuum die casting apparatus according to claim 1. Having a timer means for detecting the elapsed time;
3. The vacuum die casting apparatus according to claim 1 , wherein the control unit controls the decompression unit based on the elapsed time. 4.   The vacuum die casting apparatus according to claim 3, wherein the elapsed time is a base time when mold clamping is started. The mold clamping means has reciprocating means for driving the second mold toward the first mold so as to be close to and away from the first mold,
The vacuum die casting apparatus has a stroke detection means for detecting a stroke of the reciprocating means,
The vacuum die casting apparatus according to claim 1 , wherein the control unit controls the decompression unit based on the stroke. Pressure detecting means for detecting the pressure inside the cavity;
The vacuum die casting apparatus according to claim 1 , wherein the control unit controls the decompression unit based on the pressure. Before the clamping of the first and second molds having cavities corresponding to the outer shape of the molded product is completed, the air inside the cavity is auxiliary sucked so that the air forms the molten metal constituting the molded product. Suppressing back flow to the hot water supply pipe for introducing the molten metal into the injection means and the holding furnace holding the molten metal via the injection means for injecting into the cavity,
After the completion of mold clamping, the main suction of the air inside the cavity supplies the molten metal of the holding furnace to the injection means via the hot water supply pipe ,
The vacuum die casting method , wherein the auxiliary suction is controlled so that the molten metal in the holding furnace is not supplied to the injection means via the hot water supply pipe . The auxiliary suction is stopped the mold clamping completion immediately before, the vacuum die casting method according to claim 7 in which the pressure of the interior of said cavity and said Rukoto is suppressed to be reduced. 9. The vacuum die casting method according to claim 7 , wherein the auxiliary suction is controlled based on an elapsed time. The vacuum die casting method according to claim 9 , wherein the elapsed time is a start time of mold clamping. The auxiliary suction, based on the second mold stroke of the reciprocating means for driving the movable toward spaced toward said first mold, according to claim 7 or claim characterized in that it is controlled 8. The vacuum die casting method according to 8 . The vacuum die casting method according to claim 7 or 8 , wherein the auxiliary suction is controlled based on a pressure inside the cavity.

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