Vacuumizing equipment and process for aluminum alloy die casting

Abstract

The invention relates to the technical field of die-casting manufacturing, and discloses an aluminum alloy die-casting vacuumizing device which comprises a fixed die, a movable die and a material conveying mechanism, the fixed die and the movable die are matched with each other, the material conveying mechanism is used for pouring molten metal, a cavity is formed between the fixed die and the movable die, and a breather pipe communicated with the cavity is fixedly installed at the top of the fixed die. An air exhaust mechanism used for vacuumizing and a pressure stabilizing mechanism used for stabilizing the internal pressure of the cavity are arranged on the breather pipe in a communicating mode, the pressure stabilizing mechanism comprises a pressure stabilizing cylinder communicated with the breather pipe and an air exhaust piston arranged in the pressure stabilizing cylinder in an elastic dynamic sealing mode, and the air exhaust piston is connected with the power output end of the material conveying mechanism through a second pull rope. According to the material conveying mechanism, in the process of pouring the molten metal into the cavity, synchronous air exhaust of the cavity is achieved, so that when the molten metal is poured into the cavity, the stability of the pressure in the cavity can be kept, and the situation that gas brought into the cavity exists in the cavity is prevented, so that the flowing stability of the molten metal is improved.

Description

Technical Field

[0001] The invention relates to the technical field of die-casting manufacturing, and in particular to vacuum extraction equipment and a process for aluminum alloy die-casting. Background Art

[0002] During the die-casting process, liquid metal is sprayed into the mold cavity under high pressure, and the gas in the mold cavity often has no time to be discharged and is drawn into the molten metal, and exists in the die-casting in the form of pores, which hinders the improvement of mechanical properties and makes the die-casting that needs to withstand pressure requirements prone to leakage at the pores.

[0003] In order to reduce the occurrence of pores in die-casting parts, the prior art usually uses a vacuum die-casting method to extract the gas in the cavity, and the molten metal fills the cavity under a vacuum state. Since less gas is involved in the molten metal, the amount of pores in the die-casting machine can be reduced or eliminated.

[0004] For example, the Chinese patent with application number CN201220140238.0 and titled “A mold cavity vacuum pumping system” and the Chinese patent with application number CN201410401529.4 and titled “die casting mold cavity vacuum pumping system” both use a vacuum pump to extract the air in the cavity before injecting the molten metal, and then pour the molten metal in. However, the applicant found in the actual operation process that the existing technologies all have the following common drawbacks:

[0005] When molten metal is sprayed into the vacuum cavity, the pressure inside the cavity will suddenly change. The instantaneous change in the pressure inside the cavity can easily lead to damage to the cavity structure. Furthermore, since the cavity cannot shrink, it is difficult to extract all the gas when evacuating the cavity. The gas usually adheres to the inner wall of the cavity, and a small amount of gas is also brought into the cavity during the process of pouring liquid. The presence of these gases in the cavity will affect the stability of the liquid flow. Therefore, how to maintain the stability of the cavity pressure during the process of pouring molten metal into the vacuum cavity and prevent the gas brought into the cavity from existing in the cavity to improve the stability of the molten metal flow is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a vacuum extraction device and process for aluminum alloy die casting to solve the above-mentioned deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention provides the following technical solution: A vacuum equipment for aluminum alloy die casting, comprising a fixed mold and a movable mold that cooperate with each other and a feeding mechanism for pouring molten metal, wherein a cavity is formed between the fixed mold and the movable mold.

[0008] A vent pipe connected to the mold cavity is fixedly installed on the top of the fixed mold, and an air extraction mechanism for vacuuming and a pressure stabilizing mechanism for stabilizing the internal pressure of the mold cavity are connected to the vent pipe. The pressure stabilizing mechanism includes a pressure stabilizing cylinder connected to the vent pipe and an air extraction piston with an elastic dynamic seal arranged in the pressure stabilizing cylinder. The air extraction piston is connected to the power output end of the feeding mechanism through a second pull rope;

[0009] After the cavity is evacuated by the vacuum mechanism, the power output end of the feeding mechanism pours the molten metal into the cavity while pulling the vacuum piston to slide away from the vent pipe through the second pull rope to extract the gas in the cavity to stabilize the internal pressure.

[0010] The above-mentioned vacuum equipment for aluminum alloy die-casting, the pressure stabilizing mechanism also includes a first pull rope fixedly connected to the vacuum piston, a limiting bead is fixedly installed on the bottom end of the first pull rope, an inner sliding tube for supporting the limiting bead is arranged in the ventilation pipe, the limiting bead is connected to a blocking block through an elastic rope, and an exhaust hole matched with the blocking block is opened on the fixed mold, the elastic rope passes through the inner sliding tube and the exhaust hole to make the blocking block located in the mold cavity, and in the initial state, the first pull rope is loosely located between the limiting bead and the vacuum piston, and the exhaust hole is blocked by pulling the blocking block through the first pull rope and the elastic rope during the sliding of the vacuum piston away from the ventilation pipe.

[0011] In the above-mentioned vacuum extraction equipment for aluminum alloy die-casting, when the block blocks the exhaust hole, the bottom surface of the block is seamlessly fitted with the inner wall of the fixed mold.

[0012] In the above-mentioned vacuum pumping equipment for aluminum alloy die-casting, a hard pad is fixedly installed on the vacuum piston, and the second pull rope and the first pull rope are both fixedly connected to the hard pad.

[0013] In the above-mentioned vacuum pumping equipment for aluminum alloy die-casting, a limit block abutting against the side of the vacuum piston is fixedly installed on the inner wall of the pressure stabilizing cylinder, and a compression spring is fixedly installed between the side of the vacuum piston away from the limit block and the inner wall of the pressure stabilizing cylinder.

[0014] The above-mentioned vacuum equipment for aluminum alloy die-casting, the feeding mechanism includes a storage tank for holding molten metal, an injection cylinder connected to the storage tank and a servo cylinder, the injection cylinder is dynamically sealed with an injection piston, the injection piston is fixedly connected to the power output shaft of the servo cylinder through a push-pull rod, the injection cylinder is connected to the mold cavity through a conduit, and a switch valve is installed on the storage tank.

[0015] The above-mentioned vacuum extraction equipment for aluminum alloy die-casting has an epitaxial tube fixedly installed on the ventilation pipe, a liquid hole is provided on the epitaxial tube, an injection port is provided on the top of the fixed mold, the end of the conduit is fixedly and sealedly connected to the epitaxial tube, the top opening of the liquid hole is correspondingly connected to the bottom opening of the conduit, and the bottom opening of the liquid hole is correspondingly connected to the injection port.

[0016] The above-mentioned vacuum extraction equipment for aluminum alloy die-casting has a side hole on the vent pipe, and the epitaxial tube is connected with the inner cavity of the vent pipe through the side hole. The epitaxial tube is elastically and dynamically sealed with a plugging piece, and the plugging piece is provided with a through hole. In the initial state, the through hole is connected with the catheter and the injection port. After the block blocks the exhaust hole, the vacuum piston slides further to drive the plugging piece to slide. During the sliding of the plugging piece, the molten metal fills the cavity, and then the through hole and the port of the catheter are staggered to separate the molten metal in the catheter from the molten metal in the cavity.

[0017] In the above-mentioned vacuum pumping equipment for aluminum alloy die-casting, an elastic sheet connected to the inner cavity of the catheter is fixedly and sealedly installed on the catheter, and the metal liquid fills the mold cavity before the through hole and the port of the catheter are staggered, and the excess metal liquid squeezes the elastic sheet to bulge.

[0018] A vacuuming process for aluminum alloy die casting, based on the above-mentioned vacuuming equipment for aluminum alloy die casting, comprises the following steps:

[0019] S1: Vacuuming: Vacuuming the cavity by starting the vacuum mechanism;

[0020] S2: Cavity filling: Open the switch valve on the storage tank to allow the molten metal to flow into the injection cylinder, start the servo cylinder to make the injection piston slide in the injection cylinder so that the metal liquid in the injection cylinder is pressed into the cavity. At the same time, the injection piston drives the second pull rope to pull the exhaust piston in the pressure stabilizing cylinder to slide away from the vent pipe so that the increased gas in the cavity is extracted to ensure the stability of the cavity pressure.

[0021] S3: blocking the air extraction port: when the air extraction piston slides in a direction away from the ventilation pipe, the blocking block is pulled by the first pull rope and the elastic rope to block the exhaust hole;

[0022] S4: Blocking the feed port: After the block blocks the exhaust hole, the further sliding of the vacuum piston drives the block member to slide. During the sliding process of the block member, the molten metal fills the cavity. Then, the through hole and the port of the conduit are staggered to separate the molten metal in the conduit from the molten metal in the cavity.

[0023] S5: Unloading: Move the movable mold to separate it from the fixed mold. When the die-casting adheres to the fixed mold, the injection piston is driven to slide in the opposite direction by the servo cylinder to loosen the second pull rope. Then the elastic force of the compression spring is released, pushing the vacuum piston to slide in the opposite direction to press the gas into the ventilation pipe so that the internal pressure of the ventilation pipe increases instantly. The increased internal pressure impacts the die-casting to separate it from the fixed mold.

[0024] Beneficial effects: In the above technical scheme, the vacuum pumping equipment and process for aluminum alloy die casting provided by the present invention utilize the movement of the power output end of the feeding mechanism so that the feeding mechanism can additionally and ingeniously drive the air pumping piston to slide during the process of pouring molten metal into the cavity, thereby realizing synchronous air pumping of the cavity, without the need to provide additional special air pumping equipment. Based on the air pumping of the cavity, when pouring molten metal into the cavity, the pressure inside the cavity can be kept stable and the gas brought into the cavity can be prevented from existing in the cavity to improve the stability of the flow of molten metal.

[0025] Furthermore, in the present invention, by setting the pressure stabilizing mechanism, the air extraction piston can not only generate the function of stabilizing the internal pressure of the cavity and extracting the excess gas in the cavity to stabilize the flow of the molten metal during the sliding process, but also drive the blocking member to slide after the exhaust hole is blocked, so that the blocking member automatically separates the molten metal in the conduit from the molten metal in the cavity, so that the die casting will not adhere to the molten metal in the conduit after cooling, which is convenient for unloading the die casting after cooling, and greatly reduces the length of the convex hull formed on the surface of the die casting during molding, producing unexpected technical effects;

[0026] Furthermore, in the actual operation process, when disassembling the die-casting, the die-casting will usually adhere to the upper inner wall of the fixed mold and cannot be removed together with the movable mold. The die-casting needs to be removed by the ejection mechanism after the movable mold is removed. In the present invention, if the die-casting adheres to the inner wall of the fixed mold, it is only necessary to start the servo cylinder to reset the push-pull rod and the injection piston. During this process, the one-way air inlet valve installed on the conduit enters the gas so that the injection piston can slide smoothly and then reset. When the injection piston is reset, the compression spring pushes the air pump piston to reset. When the air pump piston is reset, it slides in the direction of the vent pipe so that the internal pressure of the vent pipe increases instantly. The increased internal pressure of the vent pipe impacts the die-casting downward to separate the die-casting from the fixed mold. There is no need to provide an ejection mechanism additionally, and the pneumatic impact is softer than the ejection mechanism and is not easy to damage the die-casting. It can be seen that in the present invention, the unexpected technical effect of assisting the unloading of the die-casting is produced in the process of resetting the air pump piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0028] Figure 1 A schematic cross-sectional view of a vacuum pumping device when the injection cylinder is filled with molten metal provided by an embodiment of the present invention;

[0029] Figure 2 The embodiment of the present invention provides Figure 1 A schematic diagram of the enlarged structure of part A;

[0030] Figure 3 A schematic diagram of the structure of the injection cylinder, the pressure stabilizing cylinder and the extension tube provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of the structure of a blocking member provided in an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of the structure of a first directional wheel provided in an embodiment of the present invention;

[0033] Figure 6 A schematic cross-sectional view of a vacuum pumping device when a block blocks an exhaust hole provided by an embodiment of the present invention;

[0034] Figure 7 The embodiment of the present invention provides Figure 6 A schematic diagram of the enlarged structure of part B in FIG.

[0035] Figure 8 A schematic cross-sectional view of a vacuum pumping device when a valve core blocks an overnight hole provided by an embodiment of the present invention;

[0036] Fig. 9 The embodiment of the present invention provides Figure 8 Schematic diagram of the enlarged structure of part C in.

[0037] Description of reference numerals:

[0038] 1. Fixed mold; 101. Exhaust hole; 102. Injection port; 2. Moving mold; 3. Cavity; 4. Storage tank; 5. Injection cylinder; 6. Injection piston; 7. Push-pull rod; 8. Servo cylinder; 9. Pressure stabilizing cylinder; 901. Opening; 10. Pumping piston; 11. Hard pad; 12. Limit block; 13. First directional wheel; 1301. Rotating shaft;

[0039] 1302, fixed wheel; 1303, arc plate; 1304, connecting rod; 14, compression spring; 15, vent pipe;

[0040] 1501, inner sliding tube; 1502, avoidance hole; 1503, center hole; 1504, side hole; 16, first pull rope; 17, second directional wheel; 18, third directional wheel; 19, second pull rope; 20, conduit; 21, blocking block; 22, elastic rope; 23, limiting bead; 24, extension tube; 2401, liquid hole; 2402, baffle; 25, sliding piston; 26, valve core; 2601, through hole; 27, tension spring; 28, fixing plate; 29, elastic sheet; 30, vacuum pump. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] First embodiment:

[0043] like Figure 1-9 As shown, the vacuum extraction equipment for aluminum alloy die casting provided by the embodiment of the present invention comprises a fixed mold 1 and a movable mold 2 which cooperate with each other and a feeding mechanism for pouring molten metal, a cavity 3 is formed between the fixed mold 1 and the movable mold 2, a vent pipe 15 connected to the cavity 3 is fixedly installed on the top of the fixed mold 1, and an exhaust mechanism for vacuum extraction and a pressure stabilizing mechanism for stabilizing the internal pressure of the cavity 3 are connected to the vent pipe 15, the pressure stabilizing mechanism comprises a pressure stabilizing cylinder 9 connected to the vent pipe 15 and an exhaust piston 10 with an elastic dynamic seal arranged in the pressure stabilizing cylinder 9, and the exhaust piston 10 is connected to the power output end of the feeding mechanism through a second pull rope 19;

[0044] After the cavity 3 is evacuated by the vacuum mechanism, the power output end of the feeding mechanism pours the molten metal into the cavity 3 while pulling the vacuum piston 10 to slide away from the vent pipe 15 through the second pull rope 19 to extract the gas in the cavity 3 to stabilize its internal pressure.

[0045] The vacuum equipment for aluminum alloy die casting provided in this embodiment is used to vacuum the cavity and can better prevent the sudden change of internal pressure during the process of pouring molten metal to protect the cavity structure. The words related to direction and position in this embodiment are relative to the accompanying drawings. The "dynamic seal" in the present invention refers to sliding and sealing. Specifically, the air extraction mechanism and the pressure stabilizing mechanism are arranged side by side on the vent pipe 15. The air extraction mechanism includes an air pump 30. The air inlet end of the air pump 30 is connected to the vent pipe 15 through a connecting pipe. A one-way air intake valve (the one-way air intake valve is a prior art and will not be described in detail) is installed on the connecting pipe. The intake can only flow from the vent pipe 15 to the air pump 30, so that the air pump 30 will not be connected to the pressure stabilizing mechanism when the pressure stabilizing mechanism is evacuating. The pressure stabilizing mechanism is used to stabilize the internal pressure of the cavity 3 when the feeding mechanism sprays molten metal into the cavity 3, and complements and interferes with the air extraction mechanism. The inner wall of the stabilizing cylinder 9 is fixedly provided with a limit block 12 which abuts against the side of the pumping piston 10 close to the vent pipe 15, and is used to limit the pumping piston 10, so that the pumping piston 10 will not slide when the pumping mechanism evacuates the cavity 3, and thus the pumping mechanism will not hinder the evacuation. The feeding mechanism has a power output end, and the metal liquid is pressed into the cavity 3 by the movement of the power output end of the feeding mechanism. Since the pumping piston 10 is connected to the power output end of the feeding mechanism through the second pull rope 19, the power output end of the feeding mechanism drives the pumping piston 10 to slide along the inner cavity of the stabilizing cylinder 9 to the side away from the vent pipe 15 during the process of the metal liquid being pressed into the cavity 3. An opening 901 is provided on the end surface of the stabilizing cylinder 9 away from the vent pipe 15 for the entry and exit of gas and for the passage of the second pull rope 19. Among them, this embodiment also includes a second directional wheel 17 and a third directional wheel 18 that are rotatably arranged, and the second pull rope 19 is closely wrapped around the second directional wheel 17 and the third directional wheel 18 in turn. The second directional wheel 17 corresponds to the pressure stabilizing cylinder 9, and is used to make the second pull rope 19 located in the pressure stabilizing cylinder 9 parallel to the inner cavity of the pressure stabilizing cylinder 9. The third directional wheel 18 corresponds to the power output end of the conveying mechanism, and is used to make the second pull rope 19 located between the third directional wheel 18 and the conveying mechanism parallel to the running direction of the conveying mechanism, so as to maximize the utilization rate of force.

[0046] The working principle of the present invention is: first, the vacuum mechanism is started to vacuum the cavity 3, then the vacuum mechanism is closed, and the feeding mechanism is started to move its power output end. The movement of the power output end of the feeding mechanism gradually presses the molten metal into the cavity 3 while driving the vacuum piston 10 to slide along the inner cavity of the pressure-stabilizing cylinder 9 toward the side away from the vent pipe 15 through the second pull rope 19. Since the internal pressure of the cavity 3 suddenly increases when the molten metal is sprayed into the cavity 3, the sliding of the vacuum piston 10 at this time just continues to vacuum the cavity 3 to reduce the internal pressure of the cavity 3, which can effectively ensure the stability of the internal pressure of the cavity 3, and can extract the gas brought into the cavity 3 when the molten metal is poured in, effectively preventing the gas brought into the cavity 3 during the process of pouring the molten metal from existing in the cavity 3, thereby ensuring the stability of the flow of the molten metal.

[0047] It can be seen that the present invention cleverly utilizes the movement of the power output end of the feeding mechanism, so that in the process of pouring molten metal into the cavity 3, the feeding mechanism can also cleverly drive the vacuum piston 10 to slide, thereby realizing the synchronous vacuuming of the cavity 3, without the need to provide additional special vacuuming equipment. Based on the vacuuming of the cavity 3, when pouring molten metal into the cavity 3, the internal pressure of the cavity 3 can be kept stable and the gas brought into the cavity 3 can be prevented from existing in the cavity 3 to improve the stability of the molten metal flow, which can effectively solve the shortcomings of the prior art.

[0048] Furthermore, the pressure stabilizing mechanism also includes a first pull rope 16 fixedly connected to the vacuum piston 10, and a limiting bead 23 is fixedly installed on the bottom end of the first pull rope 16. An inner sliding tube 1501 for supporting the limiting bead 23 is arranged in the ventilation pipe 15, and the limiting bead 23 is connected to the blocking block 21 through an elastic rope 22. An exhaust hole 101 adapted to the blocking block 21 is opened on the fixed mold 1, and the elastic rope 22 passes through the inner sliding tube 1501 and the exhaust hole 101 to make the blocking block 21 located in the cavity 3. In the initial state, the first pull rope 16 is loosely located between the limiting bead 23 and the vacuum piston 10. During the sliding process of the vacuum piston 10 away from the ventilation pipe 15, the blocking block 21 is pulled by the first pull rope 16 and the elastic rope 22 to block the exhaust hole 101. Specifically, the exhaust hole 101 is used for gas circulation, and the block 21 is used to block the exhaust hole 101. In the initial state, the exhaust hole 101 and the block 21 are staggered up and down to open the exhaust hole 101. The inner slide tube 1501 is provided with an avoidance hole 1502 for the first pull rope 16 to pass through. The inner slide tube 1501 is also provided with a center hole 1503 for gas circulation. The limiting bead 23 is used to limit the block 21, and the inner slide tube 1501 supports the limiting bead 23 so that the first pull rope 16 is in a loose state and the block 21 is at a high position staggered from the exhaust hole 101 in the initial state. The loose state of the first pull rope 16 makes the block 21 maintain a height staggered from the exhaust hole 101 when the vacuum piston 10 is pulled and slid by the second pull rope 19, so that the exhaust hole 101 will not be blocked at this time, thereby realizing the continuous exhaust of the cavity 3 by the pressure stabilizing mechanism when the molten metal is poured into the cavity 3; when the cavity 3 is full, the first pull rope 16 is in a tensioned state, and the first pull rope 16 pulls the limiting bead 23 and the elastic rope 22 upward to complete the blocking of the exhaust hole 101 by the block 21, and at this time, when the molten metal continues to be poured into the cavity 3, the molten metal can be effectively prevented from entering the exhaust hole 101.

[0049] Furthermore, when the block 21 blocks the exhaust hole 101, the bottom surface of the block 21 is seamlessly fitted with the inner wall of the fixed mold 1. At this time, the inner wall of the fixed mold 1 is in a completely flat state, so that the die-casting in the cavity 3 will not have bulges due to the existence of the exhaust hole 101 during molding, thereby ensuring the flatness of the surface of the die-casting.

[0050] In this embodiment, a hard pad 11 is fixedly mounted on the air pumping piston 10, and the second pull rope 19 and the first pull rope 16 are fixedly connected to the hard pad 11. By utilizing the characteristic that the hard pad 11 is not easily deformed, the connection between the second pull rope 19 and the first pull rope 16 and the air pumping piston 10 can be ensured to be firmly connected.

[0051] A first directional wheel 13 corresponding to the first pull rope 16 is rotatably arranged in the pressure stabilizing cylinder 9, and the first directional wheel 13 is used to limit the direction of the first pull rope 16 so that the first pull rope 16 located in the pressure stabilizing cylinder 9 is parallel to the movement direction of the vacuum piston 10, and the first pull rope 16 located in the ventilation pipe 15 is parallel to the movement direction of the block 21.

[0052] In this embodiment, a stopper 12 is fixedly installed on the inner wall of the pressure stabilizing cylinder 9 and abuts against the side of the air pumping piston 10. A compression spring 14 is fixedly installed between the side of the air pumping piston 10 away from the stopper 12 and the inner wall of the pressure stabilizing cylinder 9. The compression spring 14 is always in a compressed state so that the air pumping piston 10 abuts against the stopper 12 in the initial state. By limiting the position of the air pumping piston 10 by the stopper 12, the opening 901 can be kept blocked by the air pumping piston 10 when the air pumping mechanism is evacuated, thereby ensuring that the cavity 3 is effectively evacuated.

[0053] In this embodiment, the feeding mechanism includes a storage tank 4 for holding molten metal, an injection cylinder 5 connected to the storage tank 4, and a servo cylinder 8. The injection cylinder 5 is provided with an injection piston 6 in a dynamic seal. The injection piston 6 is fixedly connected to the power output shaft of the servo cylinder 8 through a push-pull rod 7. The injection cylinder 5 is connected to the cavity 3 through a conduit 20. A switch valve is installed on the storage tank 4. Specifically, when the switch valve on the storage tank 4 is opened, the molten metal in the storage tank 4 enters the injection cylinder 5. Then, the push-pull rod 7 and the injection piston 6 are driven to slide by starting the servo cylinder 8. The piston movement of the injection piston 6 in the injection cylinder 5 causes the molten metal in the injection cylinder 5 to enter the cavity 3 through the conduit 20. The second pull rope 19 is fixedly connected to the push-pull rod 7. The movement of the push-pull rod 7 is used to pull the second pull rope 19 to move, thereby driving the suction piston 10 to slide.

[0054] In this embodiment, an extension tube 24 is fixedly mounted on the vent pipe 15, a liquid hole 2401 is provided on the extension tube 24, an injection port 102 is provided on the top of the fixed mold 1, the end of the guide tube 20 is fixedly sealed and connected to the extension tube 24, the top of the liquid hole 2401 is correspondingly connected to the bottom of the guide tube 20, and the bottom of the liquid hole 2401 is correspondingly connected to the injection port 102. Specifically, when the metal liquid is poured into the cavity 3, the metal liquid enters the cavity 3 through the guide tube 20, the liquid hole 2401 and the injection port 102.

[0055] Due to the presence of the injection port 102 and the connection between the injection port 102 and the conduit 20, when the die-casting is cooled and formed, the molten metal at the port of the conduit 20 will also be cooled and solidified, and adhere to the die-casting, resulting in difficulty in unloading the die-casting. After unloading, a long bulge will also be generated on the surface of the die-casting, which is not conducive to storage. To this end, the present invention further provides a side hole 1504 on the vent pipe 15, and the extension tube 24 is connected to the inner cavity of the vent pipe 15 through the side hole 1504. A sealing piece is provided in the extension tube 24 for elastic dynamic sealing. A through hole 2601 is provided on the sealing piece. In the initial state, the through hole 2601 is connected to the conduit 20 and the injection port 102. After the block 21 blocks the exhaust hole 101, the vacuum piston 10 further slides to drive the sliding of the sealing piece. During the sliding of the sealing piece, the molten metal fills the cavity 3. After that, the through hole 2601 and the port of the conduit 20 are staggered to separate the molten metal in the conduit 20 from the molten metal in the cavity 3. Specifically, the sealing member includes a sliding piston 25 and a valve core 26 that are fixedly connected. The sliding piston 25 is dynamically sealed with the inner cavity of the extension tube 24. The valve core 26 slides and fits with the inner wall of the liquid hole 2401. A fixing plate 28 is fixedly installed on the extension tube 24. A tension spring 27 is fixedly connected between the valve core 26 and the fixing plate 28. A baffle 2402 that abuts against the valve core 26 is fixedly installed at the end of the extension tube 24. The tension spring 27 is always in a stretched state. In the initial state, the valve core 26 abuts against the baffle 2402 under the action of the stretching elastic force of the tension spring 27. At this time, the conduit 20, the through hole 2601, and the injection port 102 are connected, and the molten metal can enter the mold cavity 3 through the conduit 20, the through hole 2601 and the injection port 102 in sequence. At the same time, before the exhaust hole 101 is blocked by the block 21, the sliding function of the vacuum piston 10 is to extract the gas in the cavity 3 to keep the internal pressure of the cavity 3 stable. After the exhaust hole 101 is blocked by the block 21, in order to ensure that the cavity 3 is filled with molten metal, it is necessary to continue to fill the cavity 3 with molten metal. At this time, the vacuum piston 10 is pulled by the second pull rope 19 and continues to slide to increase the internal pressure of the vent pipe 15. The increase in the internal pressure of the vent pipe 15 drives the sliding piston 25 to slide toward the vent pipe 15. The sliding piston 25 drives the valve core 26 to slide synchronously until the through hole 2601 is offset from the liquid hole 2401. At this time, the valve core 26 blocks the port of the conduit 20 to automatically separate the molten metal in the conduit 20 from the molten metal in the cavity 3, so that the die-casting will not adhere to the molten metal in the conduit 20 after cooling, which is convenient for the unloading of the die-casting after cooling and greatly reduces the length of the bulge generated during the molding of the die-casting.

[0056] It can be seen that in the present invention, through the setting of the pressure stabilizing mechanism, the vacuum piston 10 can not only generate a stable internal pressure in the cavity 3 and extract excess gas in the cavity 3 to stabilize the flow of the molten metal during the sliding process, but also can drive the sealing member to slide after the exhaust hole 101 is blocked, so that the sealing member can automatically separate the molten metal in the conduit 20 from the molten metal in the cavity 3, so that the die-casting will not adhere to the molten metal in the conduit 20 after cooling, which is convenient for unloading the die-casting after cooling, and the length of the convex bulge formed on the surface of the die-casting during molding is greatly reduced, resulting in unexpected technical effects.

[0057] Furthermore, in order to ensure that the cavity 3 can be filled with molten metal and that the injection piston 6 has enough sliding space to drive the blocking piece to slide and block the port of the conduit 20 when the cavity 3 is filled with molten metal, in this embodiment, an elastic sheet 29 connected to the inner cavity of the conduit 20 is fixedly and sealedly installed on the conduit 20, and the molten metal fills the cavity 3 before the through hole 2601 and the port of the conduit 20 are offset, and the excess molten metal squeezes the elastic sheet 29 to bulge. Specifically, when the exhaust hole 101 is blocked by the block 21, as the injection piston 6 and the push-pull rod 7 further slide and drive the blocking piece to slide, the through hole 2601 and the port of the conduit 20 are gradually offset. In this process, the molten metal further enters the cavity 3, and the cavity 3 is filled with molten metal before the through hole 2601 and the port of the conduit 20 are completely offset, and then the through hole 2601 and the port of the conduit 20 are completely offset. Since the mold cavity 3 needs to be filled with molten metal before the through hole 2601 and the port of the conduit 20 are completely offset, the filling of the molten metal will cause the injection piston 6 to lack sliding space and be unable to slide further before the through hole 2601 and the port of the conduit 20 are completely offset. As a result, the vacuum piston 10 cannot be driven to slide further to completely offset the through hole 2601 and the port of the conduit 20. For this reason, in the present invention, the elastic sheet 29 is provided and the elastic properties of the elastic sheet 29 are utilized to enable the injection piston 6 to slide further. When sliding further, the molten metal squeezes the elastic sheet 29 to bulge, thereby providing space for the injection piston 6 to slide further so that the through hole 2601 and the port of the conduit 20 are completely offset.

[0058] In order to prevent the valve core 26 from rotating during the sliding process, a sliding rod with a polygonal cross-section can be fixedly installed on 26, and the sliding rod can be slidably plugged with 28, which will not be described in detail.

[0059] In this embodiment, the inner slide tube 1501 is cylindrical, and the outer peripheral surface of the inner slide tube 1501 is slidably fitted with the inner wall of the vent tube 15. The inner slide tube 1501 is slidably arranged in the vent tube 15. In the initial state, the bottom of the inner slide tube 1501 is in contact with the top of the fixed mold 1. At this time, the inner slide tube 1501 blocks the side hole 1504, so that the side hole 1504 is closed when the vacuum mechanism is vacuuming, and the blocking piece will not be driven to slide, so that the cavity 3 can be vacuumed more effectively. The inner slide tube 1501 includes an upper plate and a lower plate that are fixedly connected, and the limiting bead 23 is located between the upper plate and the lower plate. When the first pull rope 16 drives the limiting bead 23 and the blocking block 21 to move upward, the limiting bead 23 drives the inner slide tube 1501 to slide upward through the upper plate to open the side hole 1504, so that when the blocking block 21 blocks the exhaust hole 101, the side hole 1504 is in an open state, and can subsequently drive the blocking piece to slide.

[0060] In this embodiment, the elastic force of the elastic rope 22 can be used to make the block 21 block the exhaust hole 101, and then the limiting bead 23 and the inner sliding tube 1501 can be moved upward. The top of the block 21 is rounded, so that the block 21 can smoothly enter the exhaust hole 101 when it moves upward. Of course, a guide rod can also be fixed on the block 21, and the guide rod is slidably connected with the inner wall of the vent pipe 15. The sliding connection between the guide rod and the vent pipe 15 can effectively ensure the stability of the block 21 when it slides, so that the block 21 can be stably inserted into the exhaust hole 101 to block the exhaust hole 101.

[0061] In this embodiment, a one-way air inlet valve is installed on the conduit 20, and gas can enter from the outside.

[0062] The working principle after the pouring is completed is: firstly, the molten metal in the cavity 3 is cooled to form a die casting, and then the die casting is unloaded;

[0063] The disassembly method of the die-casting is as follows: first disassemble the movable mold 2. If the die-casting is not adhered to the inner wall of the fixed mold 1, the die-casting is removed together with the movable mold 2. Finally, the servo cylinder 8 is started to reset the injection piston 6 and the push-pull rod 7. The reset of the push-pull rod 7 causes the vacuum piston 10 to reset under the elastic force of the compression spring 14. The reset of the vacuum piston 10 drives the limit bead 23, the inner sliding tube 1501, and the blocking block 21 to reset under the action of gravity, and at the same time drives the sealing member to reset under the action of the tension spring 27. However, in the actual operation process, when the die-casting is disassembled, the die-casting will usually adhere to the upper inner wall of the fixed mold 1 and cannot be removed together with the movable mold 2. The die-casting needs to be removed by the ejection mechanism after the movable mold 2 is removed. In the present invention, if the die-casting adheres to the inner wall of the fixed mold 1, it is only necessary to start the servo cylinder 8 to reset the push-pull rod 7 and the injection piston 6. During this process, the one-way air inlet valve installed on the guide tube 20 enters the gas so that the injection piston 6 can slide smoothly and then reset. When the injection piston 6 is reset, the compression spring 14 pushes the air pump piston 10 to reset. When the air pump piston 10 is reset, it slides in the direction of the vent pipe 15 so that the internal pressure of the vent pipe 15 increases instantly. The increased internal pressure of the vent pipe 15 impacts the die-casting downward to separate the die-casting from the fixed mold 1. There is no need to provide an ejection mechanism additionally, and the pneumatic impact is softer than the ejection mechanism and is not easy to damage the die-casting. It can be seen that in the present invention, the unexpected technical effect of assisting the unloading of the die-casting is produced in the process of resetting the air pump piston 10.

[0064] Second embodiment:

[0065] like Figure 1-9 As shown, the vacuuming process for aluminum alloy die casting provided by the embodiment of the present invention comprises the following steps:

[0066] S1: Vacuuming: vacuuming the cavity 3 by starting the vacuum mechanism;

[0067] S2: cavity filling: open the switch valve on the storage tank 4 to allow the molten metal to flow into the injection cylinder 5, start the servo cylinder 8 to make the injection piston 6 slide in the injection cylinder 5 so that the molten metal in the injection cylinder 5 is pressed into the cavity 3, and at the same time, the injection piston 6 drives the second pull rope 19 to pull the exhaust piston 10 in the pressure stabilizing cylinder 9 to slide away from the vent pipe 15 so that the increased gas in the cavity 3 is extracted to ensure the stability of the internal pressure of the cavity 3;

[0068] S3: blocking the air extraction port: when the air extraction piston 10 slides in a direction away from the ventilation pipe 15 , the blocking block 21 is pulled by the first pull rope 16 and the elastic rope 22 to block the exhaust hole 101 ;

[0069] S4: Blocking the feed port: After the blocking block 21 blocks the exhaust hole 101, the vacuum piston 10 further slides to drive the blocking member to slide. During the sliding process of the blocking member, the metal liquid fills the cavity 3. Then, the through hole 2601 and the port of the conduit 20 are staggered to separate the metal liquid in the conduit 20 from the metal liquid in the cavity 3.

[0070] S5: Unloading: Move the movable mold 2 to separate it from the fixed mold 1. When the die-casting adheres to the fixed mold 1, the injection piston 6 is driven by the servo cylinder 8 to slide in the opposite direction to loosen the second pull rope 19. Then the elastic force of the compression spring 14 is released to push the vacuum piston 10 to slide in the opposite direction to press the gas into the vent pipe 15 so that the internal pressure of the vent pipe 15 increases instantly. The increased internal pressure impacts the die-casting to separate it from the fixed mold 1.

[0071] In step S5, after the movable mold 2 is disassembled, if the die-casting is not adhered to the inner wall of the fixed mold 1, the die-casting is removed together with the movable mold 2, and finally the servo cylinder 8 is started to reset the injection piston 6 and the push-pull rod 7. The reset of the push-pull rod 7 causes the vacuum piston 10 to reset under the elastic force of the compression spring 14. The reset of the vacuum piston 10 drives the limiting bead 23, the inner sliding tube 1501, and the blocking block 21 to reset under the action of gravity, and at the same time drives the sealing member to reset under the action of the tension spring 27.

[0072] In the present invention, the cooling mechanism for cooling the die casting is prior art and will not be described in detail.

[0073] In the present invention, the first directional wheel 13 includes a rotating shaft 1301, two fixed wheels 1302, an arc plate 1303, and multiple connecting rods 1304. The rotating shaft 1301 is rotatably installed inside the pressure-stabilizing cylinder 9, the arc plate 1303 is fixedly installed between the two fixed wheels 1302, and the two fixed wheels 1302 are rotatably sleeved on the rotating shaft 1301. One end of the multiple connecting rods 1304 is fixedly installed on one of the fixed wheels 1302, and the other end is fixedly installed on the inner wall of the pressure-stabilizing cylinder 9, so that only the rotating shaft 1301 can rotate. A space for the first pull rope 16 to pass through is formed between the rotating shaft 1301, the two fixed wheels 1302, and the arc plate 1303. The rotation of the rotating shaft 1301 is used to reduce the friction between the first pull rope 16, and the arc plate 1303 and the two fixed wheels 1302 are used to limit the first pull rope 16 so that the first pull rope 16 will not detach from the first directional wheel 13.

[0074] In the present invention, the inner diameter of the injection cylinder 5 is the same as the inner diameter of the pressure stabilizing cylinder 9 .

[0075] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A vacuum pumping device for aluminum alloy die casting, comprising a fixed die (1) and a movable die (2) that cooperate with each other and a feeding mechanism for pouring molten metal, wherein a cavity (3) is formed between the fixed die (1) and the movable die (2), and characterized in that: A vent pipe (15) connected to the mold cavity (3) is fixedly installed on the top of the fixed mold (1); an air extraction mechanism for vacuuming and a pressure stabilizing mechanism for stabilizing the internal pressure of the mold cavity (3) are connected to the vent pipe (15); the pressure stabilizing mechanism comprises a pressure stabilizing cylinder (9) connected to the vent pipe (15) and an air extraction piston (10) with an elastic dynamic seal arranged in the pressure stabilizing cylinder (9); the air extraction piston (10) is connected to the power output end of the feeding mechanism via a second pull rope (19); After the mold cavity (3) is evacuated by the vacuum mechanism, the power output end of the feeding mechanism pours the molten metal into the mold cavity (3) while pulling the vacuum piston (10) to slide in a direction away from the vent pipe (15) through the second pull rope (19) to extract the gas in the mold cavity (3) to stabilize the internal pressure.

2. The vacuum equipment for aluminum alloy die casting according to claim 1, characterized in that: The pressure stabilizing mechanism further comprises a first pull rope (16) fixedly connected to the air extraction piston (10); a limiting bead (23) is fixedly mounted on the bottom end of the first pull rope (16); an inner sliding tube (1501) for supporting the limiting bead (23) is arranged in the ventilation pipe (15); the limiting bead (23) is connected to a blocking block (21) via an elastic rope (22); and an exhaust hole (101) adapted to the blocking block (21) is provided on the fixed mold (1). The elastic rope (22) passes through the inner sliding tube (1501) and the exhaust hole (101) so that the blocking block (21) is located in the mold cavity (3). In the initial state, the first pull rope (16) is loosely located between the limiting bead (23) and the air extraction piston (10). When the air extraction piston (10) slides in a direction away from the ventilation tube (15), the blocking block (21) is pulled by the first pull rope (16) and the elastic rope (22) to block the exhaust hole (101).

3. The vacuum equipment for aluminum alloy die casting according to claim 2, characterized in that: When the blocking block (21) blocks the exhaust hole (101), the bottom surface of the blocking block (21) is seamlessly fitted to the inner wall of the fixed mold (1).

4. The vacuum equipment for aluminum alloy die casting according to claim 2, characterized in that: A hard pad (11) is fixedly mounted on the air extraction piston (10), and the second pull rope (19) and the first pull rope (16) are both fixedly connected to the hard pad (11).

5. The vacuum equipment for aluminum alloy die casting according to claim 1, characterized in that: A limit block (12) is fixedly mounted on the inner wall of the pressure stabilizing cylinder (9) and abuts against the side of the air extraction piston (10). A compression spring (14) is fixedly mounted between the inner wall of the pressure stabilizing cylinder (9) and the side of the air extraction piston (10) away from the limit block (12).

6. The vacuum equipment for aluminum alloy die casting according to claim 2, characterized in that: The feeding mechanism comprises a storage tank (4) for containing molten metal, an injection cylinder (5) connected to the storage tank (4), and a servo cylinder (8); an injection piston (6) is provided in a dynamic seal inside the injection cylinder (5); the injection piston (6) is fixedly connected to the power output shaft of the servo cylinder (8) via a push-pull rod (7); the injection cylinder (5) is connected to the mold cavity (3) via a conduit (20); and a switch valve is installed on the storage tank (4).

7. The vacuum equipment for aluminum alloy die casting according to claim 6, characterized in that: An extension tube (24) is fixedly mounted on the ventilation tube (15), a liquid passage hole (2401) is provided on the extension tube (24), an injection port (102) is provided on the top of the fixed mold (1), the end of the guide tube (20) is fixedly sealed and connected to the extension tube (24), the top of the liquid passage hole (2401) is correspondingly connected to the bottom of the guide tube (20), and the bottom of the liquid passage hole (2401) is correspondingly connected to the injection port (102).

8. The vacuum equipment for aluminum alloy die casting according to claim 7, characterized in that: The ventilation pipe (15) is provided with a side hole (1504), and the extension tube (24) is connected to the inner cavity of the ventilation pipe (15) through the side hole (1504). The extension tube (24) is provided with a sealing piece for elastic dynamic sealing. The sealing piece is provided with a through hole (2601). In the initial state, the through hole (2601) is connected to the conduit (20) and the injection port (102). After the block (21) blocks the exhaust hole (101), the suction piston (10) further slides to drive the sealing piece to slide. During the sliding process of the sealing piece, the metal liquid fills the mold cavity (3), and then the through hole (2601) and the port of the conduit (20) are staggered to separate the metal liquid in the conduit (20) from the metal liquid in the mold cavity (3).

9. The vacuum equipment for aluminum alloy die casting according to claim 8, characterized in that: An elastic sheet (29) connected to the inner cavity of the catheter (20) is fixedly and sealedly mounted on the catheter (20); before the through hole (2601) and the port of the catheter (20) are offset, the molten metal fills the mold cavity (3), and the excess molten metal squeezes the elastic sheet (29) to bulge.

10. A vacuuming process for aluminum alloy die casting, which is based on the vacuuming equipment for aluminum alloy die casting according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: vacuuming: vacuuming the cavity (3) by starting the vacuuming mechanism; S2: cavity filling: open the switch valve on the storage tank (4) to allow the molten metal to flow into the injection cylinder (5), start the servo cylinder (8) to make the injection piston (6) slide in the injection cylinder (5) so that the molten metal in the injection cylinder (5) is pressed into the cavity (3), and at the same time, the injection piston (6) drives the second pull rope (19) to pull the exhaust piston (10) in the pressure stabilizing cylinder (9) to slide away from the vent pipe (15) so that the increased gas in the cavity (3) is extracted to ensure the internal pressure of the cavity (3) is stable; S3: blocking the air extraction port: when the air extraction piston (10) slides in a direction away from the ventilation pipe (15), the blocking block (21) is pulled by the first pull rope (16) and the elastic rope (22) to block the exhaust hole (101); S4: blocking the feed port: after the blocking block (21) blocks the exhaust hole (101), the further sliding of the vacuum piston (10) drives the blocking member to slide. During the sliding process of the blocking member, the molten metal fills the cavity (3). Afterwards, the through hole (2601) and the port of the conduit (20) are staggered to separate the molten metal in the conduit (20) from the molten metal in the cavity (3); S5: Unloading: Move the movable mold (2) to separate the movable mold (2) from the fixed mold (1). When the die-casting adheres to the fixed mold (1), the injection piston (6) is driven to slide in the reverse direction through the servo cylinder (8), so that the second pull rope (19) is loosened. Then, the elastic force of the compression spring (14) is released, pushing the exhaust piston (10) to slide in the reverse direction to press the gas into the ventilation pipe (15), so that the internal pressure of the ventilation pipe (15) increases instantly. The increased internal pressure impacts the die-casting to separate the die-casting from the fixed mold (1).

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