JP2017164777A - Vacuum die-cast device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably ensure vacuum exhaustion and also restrain the occurrence of a burr when vacuum-exhausting the inside of a cavity using a communication hole with an extrusion pin placed therein.SOLUTION: A movable mold 4 has a vacuum cavity part 12 communicating with a vacuum pump 10, and the vacuum cavity part 12 communicates with a cavity 6 via a bush 18 in which an extrusion pin 14 has been inserted. For vacuum exhaustion after mold closure, the inside of the cavity 6 can be vacuum-exhausted at once by retreating the extrusion pin 14 (the state of (b)). Alternatively, in a casting process, when a pressing surface 14d is made flush with an inner surface of the cavity 6 by inserting a pin head 14c formed in the extrusion pin 14 into a second exhaust passage 18g formed in the bush 18, a part between a first exhaust passage 18f and a shaft part 14a of the extrusion pin 14 is sealed by a second seal ring 20, and a part between a body shaft part 18a of the bush 18 and a bush insertion hole 4g is sealed by a third seal ring 21 (the state of (a)).SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vacuum die casting apparatus in which a communication hole through which an extrusion member is inserted functions as an exhaust passage when evacuating the inside of a cavity.

  As is well known, a vacuum die casting apparatus performs casting by injecting and filling a molten metal held in an injection sleeve into a cavity in a state where a cavity formed by clamping a mold is evacuated. is there.

  Cast products such as recent aluminum die castings tend to be thinner due to demands for weight reduction. When the thickness of the cast product is reduced, the cross-sectional area of the cavity is reduced, so that the passage resistance when evacuating is increased and the degree of vacuum at the end is hardly increased. Further, when the shape of the thinned cavity becomes complicated, it becomes difficult for air in the cavity to escape and casting defects due to air entrainment easily occur.

  As a countermeasure, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 2004-114097), a pin insertion hole (communication hole) provided in a movable mold and through which an extrusion pin for taking out a cast product is inserted is used as a vacuum pump. A technique is disclosed in which a cavity is evacuated through a gap between a pin insertion hole and an extrusion pin (extrusion member) in communication.

JP 2004-114097 A

  In the technique disclosed in the above-described literature, the cavity is evacuated simply by utilizing the gap between the pin insertion hole and the extrusion pin. It is necessary to ensure a large gap.

  However, when the gap between the pin insertion hole and the extrusion pin is increased, the molten metal enters the gap and a cast burr is easily generated. On the other hand, when the gap is narrowed, the passage resistance is increased, and it is difficult to efficiently depressurize the inside of the cavity.

  In view of the above circumstances, the present invention can suppress the occurrence of casting burr when vacuuming the cavity using the communication hole through which the extrusion member is inserted, and stably ensure vacuuming. Furthermore, an object of the present invention is to provide a vacuum die casting apparatus that can prevent casting defects caused by air entrainment.

  The present invention includes a mold that is clamped to form a cavity therein, an evacuation device that generates a negative pressure for evacuating the inside of the cavity, and provided in the mold when the mold is opened. In a vacuum die casting apparatus comprising an extrusion mechanism having a rod-like extrusion member for extruding a product formed in a cavity, and an injection mechanism for pressurizing and pouring molten metal into the cavity, the vacuum exhaust formed on the mold A vacuum cavity communicating with the apparatus, the extrusion mechanism communicating the cavity and the vacuum cavity, a communication hole through which the extrusion member is inserted, and a drive mechanism for moving the extrusion member forward and backward And a first vacuum valve that is capable of opening and closing the communication hole in conjunction with the forward and backward movement of the push-out member.

  According to the present invention, a vacuum cavity portion that communicates with the vacuum exhaust device is formed in the mold, and the cavity and the vacuum cavity portion are communicated via the communication hole through which the extrusion member is inserted, and the communication hole is communicated with the extrusion member. Since the first vacuum valve linked to the forward / backward movement of the vacuum valve opens and closes, the first vacuum valve communicates the cavity with the vacuum cavity so that the vacuum can be drawn by the negative pressure accumulated in the vacuum cavity. Can be secured stably. As a result, the inside of the cavity can be depressurized at once, and casting defects due to air entrainment can be prevented. Furthermore, since the vacuum cavity is formed in the mold, space saving can be realized. On the other hand, by closing the space between the cavity and the vacuum cavity with the first vacuum valve, it becomes difficult for the molten metal to enter the communication hole during casting, and generation of casting burr can be suppressed accordingly.

The perspective view of the product immediately after casting by 1st Embodiment FIG. 2 is a schematic configuration diagram of the vacuum die casting apparatus, and is a cross-sectional view corresponding to II-II of the product shown in FIG. FIG. 3 is an enlarged view of the vacuum valve shown in section III of FIG. 2, wherein (a) is a sectional view of the vacuum valve in a closed state, and (b) is a sectional view of the vacuum valve in an opened state. FIG. 4 is a cross-sectional view of the main part of the extrusion mechanism shown in the IV part of FIG. Cross section of extrusion mechanism during product extrusion Process drawing showing a casting method using the same vacuum die casting apparatus A second embodiment is shown, (a) is a cross-sectional view of an extrusion mechanism during casting, (b) is a cross-sectional view of the extrusion mechanism during evacuation, and (c) is a cross-sectional view of the extrusion mechanism during product removal.

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

[First Embodiment]
1 to 5 show a first embodiment of the present invention. FIG. 1 shows a product (crude material) W immediately after casting by the vacuum die casting apparatus 1 (see FIG. 2). In addition to the product portion Wa, the product W is integrally formed with a casting plan portion Wb that is solidified in a gate portion or the like. Reference numeral P denotes a pressed position, and when the product W is taken out from the vacuum die casting apparatus 1, it is pressed by the pressing surface 14d of the extrusion pin 14 and released from the mold. A plurality of the pressed positions are disposed on the entire product portion Wa, and are disposed at a relatively short interval particularly in a portion where it is difficult to release the product W from the mold.

  As shown in FIG. 2, the mold 2 attached to the vacuum die casting apparatus 1 has a fixed mold 3 and a movable mold 4, and the fixed mold 3 is fixed to the vacuum die casting apparatus 1. A movable holding plate 5 for holding 4 is clamped to a fixed die 3 and freely opened by a hydraulic cylinder (not shown) via a toggle mechanism or the like. Cavity forming surfaces 3 a and 4 a are formed on the opposing surface of the fixed die 3 and the movable die 4. The cavity forming surfaces 3a and 4a form an inner surface of a cavity 6 formed inside by clamping the fixed mold 3 and the movable mold 4, and a product as shown in FIG. A surface shape of W is formed.

  Further, the tip of the injection sleeve 7 is fitted to one side (lower part in FIG. 2) of the fixed mold 3 from the back surface of the fixed mold 3, and the injection mechanism 9 is provided on the injection sleeve 7. . The injection mechanism 9 is fixed to the injection cylinder 9a connected to the rear end of the injection sleeve 7, the rod 9b extending from the injection cylinder 9a into the injection sleeve 7, and the tip of the rod 9b. An injection plunger 9c that slides in the injection sleeve 7 is provided. A hot water supply port 7 a is opened in the middle of the injection sleeve 7. The injection mechanism 9 pressurizes the molten metal M made of aluminum or aluminum alloy supplied to the injection sleeve 7 and pours it into the cavity 6. Reference numeral La is a ladle that draws molten metal and supplies hot water into the injection sleeve 7 from the hot water supply port 7a.

  Further, an exhaust port 4c for discharging air in the cavity 6 formed by clamping the die is opened at a predetermined position (upper part in FIG. 2) of the cavity forming surface 4a of the movable die 4. The exhaust port 4c communicates with an exhaust passage 4d formed in the movable mold 4, and the exhaust passage 4d communicates with a vacuum pump 10 which is an example of a vacuum exhaust apparatus provided outside.

  A second vacuum valve 11 is provided at the exhaust port 4c. As shown in FIG. 3, the second vacuum valve 11 is, for example, an electromagnetic valve, and includes a valve body 11a fixed to the movable mold 4 and a valve body 11b that is opened and closed by the valve body 11a. ing. When the valve body 11a is in the OFF state, the valve body 11b is brought into close contact with the exhaust port 4c and closed ((a) state). In the ON state, the valve body 11b protrudes as shown in FIG. The valve is then opened (state (b)).

  Further, a vacuum cavity 12 is formed in the movable mold 4. The vacuum cavity portion 12 is formed substantially along the back surface of the movable mold 4 and is partitioned from the cavity forming surface 4a via a partition wall portion 4b. The vacuum cavity 12 is communicated with the vacuum pump 10. The vacuum pump 10 is always driven during casting, and a negative pressure is constantly accumulated in the vacuum cavity 12 by driving the vacuum pump 10.

  Further, the movable die 4 is provided with a through hole 4e penetrating from the cavity forming surface 4a in the direction of the movable die holding disk 5, and the through hole 4e is provided as an extrusion member provided in the extrusion mechanism 13. A rod-like push pin 14 is slidably inserted. The push pin 14 is mainly for releasing the product W attached to the cavity forming surface 4a of the movable mold 4 which has been opened by the protruding operation. It is disposed on the position P. A plurality of through-holes 4e through which the push pins 14 are inserted are formed at predetermined positions so that each part of the product W is released from the cavity forming surface 4a almost simultaneously by the protruding operation of the push pins 14.

  The base end of each push pin 14 protrudes from the back surface of the movable die 4 and is connected to a pin holding plate 15. The pin holding plate 15 is connected to a hydraulic cylinder or the like fixed to the movable type holding plate 5. It is connected to a pin drive actuator 16. The pin holding plate 15 and the pin drive actuator 16 constitute the drive mechanism of the present invention.

  A columnar support portion 17 is formed in the vacuum cavity portion 12. The inside of the columnar support portion 17 is formed in a hollow shape through which the above-described through hole 4e passes. Further, the columnar support portion 17 supports the space between the partition wall 4b side of the vacuum cavity portion 12 and the facing surface 4f facing the same, so that the inside of the vacuum cavity portion 12 can withstand a high degree of vacuum. It is reinforced.

  Further, the through hole 4e is formed with a bush insertion hole 4g from the middle of the columnar support portion 17 to the cavity forming surface 4a to which the body shaft portion 18a of the bush 18 constituting the extrusion mechanism 13 is mounted.

  The bush 18 has substantially the same material as that of the movable die 4, and a large diameter portion 18b is integrally formed at one end of the main body shaft portion 18a, and an opening hole 18c is formed on one side of the large diameter portion 18b. Yes. On the other hand, the columnar support portion 17 is provided with a communication port 17 a that exposes the opening hole 18 c to the vacuum cavity portion 12. The other end of the body shaft portion 18a of the bush 18 is formed flush with the cavity forming surface 4a. The bush 18 is prevented from coming off into the through hole 4e by the large diameter portion 18b.

  A shaft portion 14a on the base side formed on the push pin 14 is slidably inserted into the through hole 4e. On the other hand, the distal end side of the push pin 14 inserted through the bush 18 is formed in a rod-like bowl shape having a small diameter shaft portion 14b, and a pressing surface 14d is formed on the distal end surface of the pin head 14c as the first large diameter shaft portion. Has been. A first exhaust chamber 18d as a second large-diameter hole communicating with the opening hole 18c is formed in the large-diameter portion 18b of the bush 18, and a second exhaust as a first large-diameter hole is formed on the tip side. An exhaust chamber 18e is formed. Further, a first exhaust passage 18f serving as a second small-diameter hole is formed between the exhaust chambers 18d and 18e, and the first small-diameter hole is opened to the cavity forming surface 4a on the distal end side of the second exhaust chamber 18e. The second exhaust passage 18g is formed, and these portions 18c to 18g are connected in series. In addition, the communication holes of the present invention are constituted by these portions 18c to 18g.

  FIG. 4 is an enlarged view of a main part of the extrusion mechanism 13. The extrusion mechanism 13 has the same configuration in all the extrusion pins 14. Each push pin 14 is moved to a first position where the pressing surface 14d shown in FIG. A second position where the pin head 14c shown is immersed in the second exhaust chamber 18e to allow the vacuum cavity 12 and the cavity 6 to communicate with each other, and a third position where the pin head 14c shown in FIG. Moves forward and backward to position 3.

  A shaft portion 14a on the base side of the push pin 14 is slidably inserted into a through hole 4e formed in the movable die 4, and a first seal ring is interposed between the shaft portion 14a and the through hole 4e. 19 is interposed to seal between the two. Further, a shaft portion 14 a as a second large diameter shaft portion is slidably inserted into a first exhaust passage 18 f formed in the bush 18. A second seal ring 20 is attached to the inner periphery of the first exhaust passage 18f, and the shaft portion 14a and the first exhaust passage 18f are slidably contacted and sealed by the second seal ring 20. The A third seal ring 21 is interposed between the main body shaft portion 18a of the bush 18 and the bush insertion hole 4g, and the third seal ring 21 provides a space between the main body shaft portion 18a and the bush insertion hole 4g. Are joined and sealed.

  When the push pin 14 is in the first position shown in FIG. 4A, the pin head 14c is supported by the second exhaust passage 18g, and the shaft portion 14a is supported by the first exhaust passage 18f. 14a is joined and sealed by the second seal ring 20, and the second exhaust passage 18g is closed by the pin head 14c. The first vacuum valve of the present invention is constituted by the shaft portion 14a, the small-diameter shaft portion 14b, and the pin head 14c on the distal end side of the push pin 14.

  On the other hand, when the push pin 14 is in the second position shown in FIG. 4B, the pin head 14c is immersed in the second exhaust chamber 18e of the bush 18 and the small-diameter shaft portion 14b faces the first exhaust passage 18f. Therefore, the second exhaust passage 18g and the vacuum cavity 12 are communicated.

  When the push pin 14 is in the third position shown in FIG. 4C, the shaft portion 14a is supported by the through hole 4e and the exhaust passages 18f and 18g, and the pin head 14c protrudes.

  The operation of the vacuum die casting apparatus 1 is controlled by a controller (not shown). The controller is configured to include a computer having a CPU, ROM, RAM, nonvolatile memory, etc., and the CPU operates the vacuum die casting apparatus 1 along the process shown in FIG. 5 in accordance with a program written in the ROM. .

  At the start of casting, the fixed mold 3 and the movable mold 4 of the vacuum die casting apparatus 1 are opened. Further, in the small diameter shaft portion 14 b formed on the distal end side of each push pin 14 constituting the push mechanism 13 and the pin head 14 c, the pin holding disk 15 that supports the base end of the push pin 14 has a pin drive actuator 16. By being pushed out toward the back surface of the movable mold 4 by the operation, it is in the third position protruding from the cavity forming surface 4a as shown in FIG.

  First, a spray cassette is inserted between the fixed mold 3 and the movable mold 4 that are opened (step S1), and a release agent is sprayed from the spray cassette so that the fixed mold 3 and the movable mold 4 The mold release agent is applied to the mating surfaces, the cavity forming surfaces 3a and 4a, the small diameter shaft portion 14b of the extrusion pin 14 discharged from the cavity forming surface 4a, and the pin head 14c (step S2).

  Next, an air blow is blown onto the mating surface of the fixed mold 3 and the movable mold 4, the cavity forming surfaces 3a and 4a, and the tip of the extrusion pin 14 discharged from the cavity forming surface 4a, and an excess mold release agent, Then, the cast burrs and the like adhering to the surface are blown off and the water is evaporated (step S3).

  Thereafter, the valve body 11a of the second vacuum valve 11 is turned on, and the valve body 11b is opened as shown in FIG. 3B (step S4). Further, the pin holding disk 15 is moved in the direction away from the back surface of the movable mold 4 by the operation of the pin drive actuator 16, and each push pin 14 is retracted to form at the tip as shown in FIG. 4B. The pin head 14c thus moved is moved to the second position for immersing it in the second exhaust chamber 18e formed in the bush 18 (step S5).

  Thereafter, as shown in FIG. 2, the fixed mold 3 and the movable mold 4 are clamped (step S6). Then, the cavity 6 sealed in the mold 2 is formed by the cavity forming surfaces 3 a and 4 a, and the inside of the cavity 6 is evacuated by driving the vacuum pump 10. That is, the air in the cavity 6 is first opened from the second exhaust passage 18g formed in the bush 18 by the retreat of each push pin 14, as shown in FIG. 4B, to the second exhaust chamber 18e. Then, the air flows into the vacuum cavity 12 formed in the movable mold 4 through the first exhaust passage 18f, the first exhaust chamber 18d, and the opening hole 18c, and is exhausted from the vacuum cavity 12 through the vacuum pump 10. .

  On the other hand, since the valve body 11b of the second vacuum valve 11 is open, the air in the cavity 6 is exhausted from the exhaust port 4c and the exhaust passage 4d through the vacuum pump 10.

  As a result, in the present embodiment, not only the second vacuum valve 11 but also the position where each extrusion pin 14 is disposed, that is, the position corresponding to the pressed position P of the product W shown in FIG. Since the inside is evacuated, even when the thickness of the product W formed by the cavity 6 is thin and the shape is complicated, when the molten metal M is pressurized and poured in step S8, which will be described later, all at once. The inside of the cavity 6 can be depressurized. Further, since a negative pressure is always accumulated in the vacuum cavity portion 12, it is possible to stably secure a vacuum, and it is possible to maintain a high degree of vacuum even at the end in the cavity 6.

  Thereafter, the molten metal M drawn up by the ladle La is supplied from the hot water supply port 7a opened in the injection sleeve 7 (step S7). Next, by the operation of the injection cylinder 9 a provided in the injection mechanism 9, the injection plunger 9 c fixed to the tip of the rod 9 b is caused to project, and the molten metal M in the injection sleeve 7 is pressurized and poured into the cavity 6. (Step S8). At that time, as described above, the air in the cavity 6 is depressurized all at once.

  Then, the pin driving actuator 16 is operated to move the pin holding plate 15 to a movable type at a timing slightly earlier than the time until the molten metal M that has been pressurized and poured reaches the extrusion pin 14 at the nearest position. Move in the direction of 4 by a predetermined amount. Then, as shown in FIG. 4A, the pin head 14c formed at the tip of the push pin 14 is inserted into the second exhaust passage 18g formed in the bush 18, and the pressing surface 14d formed at the tip is the cavity forming surface. It becomes the first position flush with 4a, and the second exhaust passage 18g is closed. At the same time, the shaft portion 14a is inserted into the first exhaust passage 18f, and the first exhaust passage 18f is closed (step S9). Note that the timing of moving the push pin 14 to the first position is determined by any one of a time set by a timer set in advance, a hot water surface sensor, a vacuum level measurement value, or a combination thereof.

  As a result, in the first position, the space between the cavity 6 and the vacuum cavity portion 12 is blocked by the first and second exhaust passages 18f and 18g formed in the bush 18. The shaft portion 14a of the push pin 14 and the through hole 4e and the first exhaust passage 18f are joined and sealed by the first and second seal rings 19 and 20. Further, the main body shaft portion 18a of the bush 18 and the bush insertion hole 4g are joined and sealed by a third seal ring 21. Accordingly, it is difficult for the molten metal M to be sucked from between the main body shaft portion 18a exposed to the cavity forming surface 4a and the bush insertion hole 4g and between the pin head 14c of the push pin 14 and the second exhaust passage 18g. The occurrence of casting burrs can be suppressed.

  Next, the valve body 11a of the second vacuum valve 11 is operated to close the valve body 11b, and the exhaust port 4c is closed (step S10). Since a high degree of vacuum is secured in the cavity 6 in this state, casting defects due to air entrainment can be effectively prevented.

  The pressure is maintained until the molten metal M poured into the cavity 6 is cooled and solidified while maintaining the pressurized state by the injection plunger 9c (step S11). Thereafter, the product W is formed by solidifying the molten metal M poured into the cavity 6. Next, the movable mold 4 is separated from the fixed mold 3 to perform mold opening (step S12). In this embodiment, the solidified product W is designed to be released from the cavity forming surface 3a of the fixed mold 3 and to be opened in a state of being fitted to the cavity forming surface 4a of the movable mold 4. Yes.

  Thereafter, the pin driving actuator 16 is operated to further slide the pin holding plate 15 toward the back surface of the movable mold 4 by a predetermined stroke, and move the push pin 14 to the third position shown in FIG. S13). Then, the product W in which the pressing surface 14d formed at the tip of the extrusion pin 14 is fitted to the cavity forming surface 4a is extruded, and the product W in which the product part Wa and the casting plan part Wb are integrally formed is formed as a cavity. It is taken out from the surface 4a (step S14). Thus, the current casting is completed, and the vacuum die casting apparatus 1 is ready for the next casting operation.

  As described above, in this embodiment, each extrusion mechanism 13 is provided with the bush 18 for inserting and supporting the extrusion pin 14 so as to advance and retreat, and the movable die 4 is formed with the vacuum cavity 12 communicating with the vacuum pump 10. Since the vacuum cavity portion 12 communicates with the cavity 6 via the bush 18, the vacuum cavity portion 12 functions as a negative pressure chamber that constantly accumulates negative pressure, and a high degree of vacuum can be stably obtained. it can. Therefore, the entire cavity 6 can be quickly evacuated, the wall thickness is thin, the shape is complicated, and a high degree of vacuum can be ensured even if the passage resistance during pressure pouring is large. As a result, air entrainment within the cavity 6 is prevented, and the occurrence of casting defects can be suppressed.

  Furthermore, since the vacuum cavity 12 functions as a negative pressure chamber that constantly accumulates negative pressure, it is not necessary to add a large capacity vacuum pump, and the existing vacuum pump 10 can be shared. In addition, since it is not necessary to provide a negative pressure chamber separately, the equipment cost can be reduced and the space can be saved.

  In addition, since the air in the cavity 6 can be evacuated at once, the time for reducing the degree of vacuum in the cavity 6 to a predetermined value is shortened, and the productivity is improved by shortening the casting cycle time. Can do. Furthermore, since the vacuum cavity 12 formed in the movable mold 4 is supported by the columnar support 17 that inserts and supports the extrusion pin 14, sufficient reinforcement strength can be obtained even when the degree of vacuum in the vacuum cavity 12 is high. Can be obtained.

[Second Embodiment]
FIG. 6 shows a second embodiment of the present invention. In the first embodiment described above, the first exhaust passage 18f formed in the bush 18 and the shaft portion 14a of the push pin 14 and the space between the main body shaft portion 18a of the bush 18 and the bush insertion hole 4g are provided in the first embodiment. 2 and 3 are sealed using the third seal rings 20 and 21, but the extrusion mechanism 13 employed in the present embodiment is sealed using the first and second compression seal rings 33 and 34. is there. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, description is abbreviate | omitted or simplified.

  A bush insertion hole 4g as a communication hole is formed on the cavity forming surface 4a side of the through hole 4e, and a slide bush 31 is slidably mounted in the bush insertion hole 4g. The slide bush 31 is formed with a narrow diameter portion 31b at the rear end, and the small diameter portion 31b is inserted into a small diameter hole portion 4h formed at the rear portion of the bush insertion hole 4g. Further, the small-diameter hole portion 4 h communicates with a communication port 17 a that opens to the vacuum cavity portion 12.

  A small-diameter shaft portion 14b formed on the push pin 14 is slidably inserted into a pin insertion hole 31e as a shaft insertion hole formed in the slide bush 31. A pin head 14c as a third large-diameter shaft portion, which is integrally formed at the tip of the small-diameter shaft portion 14b, has the same outer diameter as the slide bush 31, and is shown in FIGS. 6 (a) and 6 (b). The bush insertion hole 4g is slidable. A compression spring 32 as a compression spring member is interposed between the pin head 14 c and the tip end surface of the slide bush 31.

  A first exhaust groove 4j is formed along the axial direction on the inner peripheral side of the bush insertion hole 4g. On the other hand, an exhaust opening hole 31d is formed at a position facing the first exhaust groove 4j of the slide bush 31. Furthermore, the 2nd exhaust groove 14e is formed in the position facing the 1st exhaust groove 4j of the small diameter shaft part 14b of the extrusion pin 14 along the axial direction. The first vacuum valve of the present invention is constituted by the small-diameter shaft portion 14b of the push pin 14, the pin head 14c, the slide bush 31, and the compression spring 32.

  A first compression seal ring 33 as a first compression seal member is attached to the small-diameter shaft portion 14b of the push pin 14 exposed on the rear end surface 31a side of the slide bush 31. Further, a second compression seal ring 34 as a second compression seal member is attached to the small diameter portion 31 b formed at the rear portion of the slide bush 31.

  Further, in the second position shown in FIG. 6B, that is, by the operation of the pin drive actuator 16, each push pin 14 is retracted and the pin head 14c is inserted into the bush insertion hole 4g in step S5 of the first embodiment. In the operation to be executed, as the push pin 14 moves backward, the small diameter portion 31b of the slide bush 31 is inserted into the small diameter hole portion 4h formed in the bush insertion hole 4g. Further, the shoulder 31c formed at the front end of the small diameter portion 31b is pressed against the stopper step portion 4i formed at the front end of the small diameter hole 4h via the second compression seal ring 34, and the rearward sliding is restricted. Is done.

  On the other hand, the push pin 14 moves backward against the urging force of the compression spring 32 and is stopped by the pin drive actuator 16 at a preset stroke. Then, the bush insertion hole 4g and the first exhaust groove 4j communicate with each other in front of the pressing surface 14d. The first exhaust groove 4j and the second exhaust groove 14e formed in the small diameter shaft portion 14b communicate with each other through an exhaust opening hole 31d formed in the slide bush 31. Further, the second exhaust groove 14 e is exposed from the rear end surface 31 a of the slide bush 31 and communicated with the communication port 17 a that opens to the vacuum cavity 12.

  As a result, the air in the cavity 6 passes through the first exhaust groove 4j from the bush insertion hole 4g opened in the cavity forming surface 4a, passes through the exhaust opening hole 31d, and passes through the second exhaust groove 14e formed in the push pin 14. It passes through the communication port 17 a and is discharged to the vacuum cavity 12. Therefore, similarly to the first embodiment described above, also in this embodiment, in the step of pressurizing and pouring the molten metal M into the cavity 6 (step S8), the air in the entire cavity 6 is quickly exhausted, and the cavity 6 The inside can be kept uniform and at a high degree of vacuum.

  Note that the distance between the movement distance from the first position to the second position of the pin head 14c and the stepped portion 14f formed on the proximal end side of the narrow diameter portion 31b of the push pin 14 from the rear end surface 31a of the slide bush 31. Are set identically.

  6A, that is, by the operation of the pin drive actuator 16, the pressing surface 14d of the pin head 14c formed at the tip of each push pin 14 is flush with the cavity forming surface 4a. In the operation executed in step S9 of the first embodiment, the pin head 14c closes the bush insertion hole 4g. Further, the slide bush 31 is pressed toward the back surface of the movable mold 4 by receiving the urging force of the compression spring 32.

  Then, the shoulder 31c of the slide bush 31 is pressed against the stopper step 4i formed in the bush insertion hole 4g via the second compression seal ring 34, and the outer periphery of the slide bush 31 and the inner periphery of the bush insertion hole 4g are sealed. The On the other hand, as described above, the distance from the first position to the second position of the pin head 14c is the same as the width from the rear end surface 31a of the slide bush 31 to the step portion 14f of the push pin 14 at the second position. Therefore, the stepped portion 14f of the push pin 14 is pressed against the rear end surface 31a of the slide bush 31 via the first compression seal ring 33 in a state where the pressing surface 14d is flush with the cavity forming surface 4a.

  Thus, in the first position, the space between the outer periphery of the slide bush 31 and the bush insertion hole 4g that slidably supports it is sealed by the second compression seal ring 34, and the outer periphery of the small-diameter shaft portion 14b and The first compression seal ring 33 seals the space between the inner periphery of the pin insertion hole 31e that slidably supports the pin. As a result, even if the inside of the vacuum cavity 12 has a high degree of vacuum, the molten metal M is hardly sucked from between the pin head 14c of the push pin 14 exposed on the cavity forming surface 4a and the bush insertion hole 4g. Thus, the occurrence of casting burrs can be suppressed.

  Further, since the first and second compression seal rings 33 and 34 are sealed by the axial surface pressure, the sliding wear is less than that of the second and third seal rings 20 and 21 of the first embodiment. High durability can be obtained.

  Further, the third position shown in FIG. 6C, that is, the operation executed in step S13 of the first embodiment, in which the pin head 14c of each push pin 14 protrudes from the cavity forming surface 4a by the operation of the pin drive actuator 16. Then, the pressing surface 14d of the pin head 14c presses the product W to release the mold from the cavity forming surface 4a by the protruding operation of the push pin 14.

  As the push pin 14 protrudes, the slide bush 31 receives the urging force of the compression spring 32 and relatively moves in the direction of the step 14 f of the push pin 14, and the rear end surface 31 a moves the first compression seal ring 33. Through the stepped portion 14 f of the push pin 14. As a result, the movement of the slide bush 31 is restricted, and the bush insertion hole 4g that opens to the cavity forming surface 4a is closed at the tip of the slide bush 31. Therefore, even if the step S2 of the first embodiment is performed in this state, the release agent is applied to the cavity forming surface 4a, and the release agent enters the vacuum cavity 12 from the bush insertion hole 4g. There is no. Moreover, the casting burr | flash adhering to the pin head 14c is blown off similarly to 1st Embodiment by the air blow performed by subsequent step S3.

  Thus, in the present embodiment, the pin head 14c closes the opening of the bush insertion hole 4g. In the first position shown in FIG. The portion 14b and the pin insertion hole 31e through which it is inserted are sealed, and further, the second compression seal ring 34 seals between the slide bush 31 and the bush insertion hole 4g through which it is inserted. Thus, even when the degree of vacuum in the cavity 6 is lower than the degree of vacuum in the vacuum cavity 12, the molten metal M is hardly sucked from between the pin head 14c of the push pin 14 and the bush insertion hole 4g. Thus, the occurrence of casting burrs can be suppressed.

  Further, since the sealing is performed by the surface pressure by the compression seal rings 33 and 34, even if the push pin 14 and the slide bush 31 slide relative to both the compression seal rings 33 and 34, there is little sliding wear and high durability. Sex can be obtained.

  The present invention is not limited to the above-described embodiments. For example, the extrusion mechanism 13 may be individually added to a portion in the cavity 6 where it is difficult to reduce the pressure, and the diameter of the pin head 14c needs to be uniform. No, it is also possible to reduce the flow resistance by increasing the diameter of the part that is difficult to reduce pressure.

  Furthermore, the operation of the push pin 14 provided in the push mechanism 13 to the second position shown in FIGS. 4B and 6B is individually operated by an actuator attached to each push pin 14 individually. You may make it let it. Therefore, in this case, this actuator is the drive mechanism of the present invention. According to this aspect, since the extrusion pins 14 that are moved to the second position can be individually operated, each extrusion pin 14 is operated in accordance with the position of the molten metal M flowing into the cavity 6 (hot water). Is possible.

1 ... Vacuum die casting equipment,
2 ... Mold,
3 ... fixed type,
3a, 4a ... cavity forming surface,
4 ... Moveable type,
4b ... partition wall,
4c ... exhaust port,
4d ... exhaust passage,
4e ... through hole,
4f ... opposite surface,
4g ... Bushing insertion hole,
4h ... small diameter hole,
4i: Stopper step,
4j ... 1st exhaust groove,
5 ... Movable holding board,
6 ... cavity,
7 ... Injection sleeve,
9 ... Injection mechanism,
10 ... Vacuum pump,
11 ... second vacuum valve,
12 ... vacuum cavity,
13 ... Extrusion mechanism,
14: Extrusion pin,
14a ... shaft part,
14b ... small diameter shaft,
14c ... pin head,
14d: pressing surface,
14e ... the second exhaust groove,
14f ... the step,
15 ... Pin holding board,
16: Pin drive actuator,
17 ... Columnar support,
17a ... communication entrance,
18 ... Bush,
18a ... main body shaft,
18b ... large diameter part,
18c ... opening hole,
18d ... first exhaust chamber,
18e ... the second exhaust chamber,
18f ... 1st exhaust passage,
18g ... the second exhaust passage,
19 ... first seal ring,
20 ... second seal ring,
21 ... Third seal ring,
31 ... Slide bush,
31a ... rear end surface,
31b ... small diameter part,
31c ... shoulder,
31d: exhaust opening hole,
31e ... Pin insertion hole,
32 ... Compression spring,
33. First compression seal ring,
34. Second compression seal ring,
M ... molten metal,
P: Pressed position,
W ... Product,

Claims (6)

A mold that is clamped to form a cavity inside,
An evacuation device for generating a negative pressure for evacuating the cavity;
An extrusion mechanism having a rod-like extrusion member that is provided in the mold and extrudes a product formed in the cavity when the mold is opened;
In a vacuum die casting apparatus comprising an injection mechanism for pressurizing and pouring molten metal into the cavity,
A vacuum cavity formed in the mold and communicating with the vacuum exhaust device;
The extrusion mechanism is
A communication hole that communicates the cavity and the vacuum cavity and through which the push member is inserted, and
A drive mechanism for advancing and retracting the pushing member;
A vacuum die casting apparatus comprising: a first vacuum valve capable of opening and closing the communication hole in conjunction with an advance / retreat operation of the push member. 2. A columnar support portion which supports a space between a partition wall portion on the cavity side of the vacuum cavity portion and a facing surface facing the partition wall portion and has the communication hole therein. The vacuum die casting apparatus described. The communication hole is
A first small-diameter hole opening at one end in the cavity;
A first large diameter hole continuous to the other end of the first small diameter hole;
A second large-diameter hole opening in the vacuum cavity;
A second small diameter hole formed between the first large diameter hole and the second large diameter hole;
The first vacuum valve provided on the pushing member is
A first large-diameter shaft portion inserted through the first small-diameter hole portion;
A second large-diameter shaft portion inserted through the second small-diameter hole portion;
The second small-diameter hole portion formed between the first large-diameter shaft portion and the second large-diameter shaft portion when the first large-diameter shaft portion faces the first large-diameter hole portion. 3. The vacuum die casting apparatus according to claim 1, further comprising a small-diameter shaft portion that allows the first large-diameter hole portion and the second large-diameter hole portion to communicate with each other. The communication hole is formed in the bush;
The bush is attached to a bush insertion hole penetrating from the columnar support portion to the cavity.
The outer periphery of the bush and the bush insertion hole are joined via a seal ring,
4. The vacuum die casting apparatus according to claim 3, wherein another seal ring slidable on the second large-diameter shaft portion is mounted on the inner periphery of the second small-diameter hole portion. The communication hole is a bush insertion hole that opens at one end to the cavity and communicates the other end with the vacuum cavity.
The first vacuum valve is
A slide bush inserted into the bush insertion hole;
A small-diameter shaft portion formed in the pushing member and inserted through the slide bush;
A third large-diameter shaft portion formed at the tip of the small-diameter shaft portion that has the same outer diameter as the slide bush and protrudes from the tip of the slide bush;
A compression spring member interposed between the slide bush and the third large diameter shaft portion;
A first exhaust groove formed along the axial direction on the inner periphery of the bush insertion hole and communicating with the cavity when the large-diameter shaft portion is immersed in the bush insertion hole;
A second exhaust groove formed on one side of the small diameter shaft portion along the axial direction and communicating with the vacuum cavity when immersed in the bush insertion hole;
When the large-diameter shaft portion is formed in the slide bush and is inserted into the bush insertion hole, the exhaust spring is moved in the same direction as the large-diameter shaft portion by the urging force of the compression spring member. The vacuum die casting apparatus according to claim 1 or 2, further comprising an exhaust opening. When the pressing surface formed at the front end of the third large-diameter shaft portion is flush with the inner surface of the cavity, between the slide bush and the small-diameter shaft portion of the push-out member inserted through the slide bush. Between the inner periphery of the bush insertion hole and the outer periphery of the slide bush inserted into the bush insertion hole through the first compression seal member. The vacuum die casting apparatus according to claim 5, wherein the vacuum die casting apparatus is pressed by a surface pressure in the axial direction via

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