An ultra-high voltage GIS aluminum alloy conductor forming device

Abstract

The application belongs to the technical field of metal casting, and particularly relates to an ultra-high-voltage GIS aluminum alloy conductor forming device, which comprises a low-pressure precision casting machine and a forming die. A forming die is arranged on a workbench. The forming die comprises two opposite die seats. The opposite sides of the two die seats are both mounted on hydraulic mechanisms. A slide is arranged between the two die seats. A slide plate is arranged in the slide. Two bottom core head seats are fixed on the slide plate. A vertical rod is fixed in the bottom core head seat. Pouring gates are arranged on the top of the bottom core head seat. A sand core is sleeved on one of the vertical rods. A top core head seat is arranged on the top of the sand core, and a groove is arranged on the top of the top core head seat. The top core head seat is sleeved on the vertical rod. The coaxial positioning assembly composed of the vertical rod, the top core head seat and the bottom core head seat provides rigid limiting for the sand core in the whole process, so that the problems of radial deviation and deflection of the sand core are avoided.

Description

Technical Field

[0001] This invention belongs to the field of metal casting technology, specifically a forming device for ultra-high voltage GIS aluminum alloy conductors. Background Technology

[0002] Ultra-high voltage (UHV) and extra-high voltage (UHV) GIS aluminum alloy conductors are core current-carrying components within GIS equipment, responsible for high-current transmission and electrical circuit connectivity. Among these, the integrated straight-cylinder GIS aluminum alloy conductor is the most widely used and fundamental type in GIS main busbars and straight-line interval circuits. It is a coaxial, equal-diameter, hollow, straight-cylinder aluminum alloy current-carrying component formed through integrated casting. This type of conductor has a completely symmetrical hollow cylindrical structure, with the main body being a tubular current-carrying section of uniform wall thickness. It is a core fundamental component for the safe and stable operation of UHV and extra-high voltage power grids.

[0003] Currently, integrated cylindrical GIS aluminum alloy conductors are mainly produced using die casting. The core molding process relies on the collaborative work of the die casting mold and the die casting machine. After the die casting mold is closed, it forms a closed cavity that perfectly matches the shape of the conductor. The bottom center of the fixed mold has an inner sprue that is sealed and connected to the injection system and riser pipe of the die casting machine. At the corresponding positions of the centers of the fixed mold and the moving mold cavity, coaxial upper and lower core head seats are respectively opened for the positioning and installation of the sand core. The inner cavity of the conductor is formed by a cylindrical resin-coated sand core of equal diameter. Both ends of the sand core have coaxial positioning core heads that match the core head seats. In the mold-closed state, the uniform annular gap between the outer wall of the sand core and the inner wall of the cavity is the forming wall thickness of the conductor. Afterwards, the die casting process begins. The die casting machine, through a pressure-driven system, smoothly presses the molten aluminum alloy from the inner sprue at the bottom of the fixed mold into the closed cavity. The molten aluminum smoothly fills the cavity from bottom to top along the annular gap between the sand core and the cavity until it is completely filled. After filling, the process enters the pressure holding and solidification stage, where a constant pressure is continuously applied until the casting in the cavity is completely solidified, eliminating internal defects caused by solidification shrinkage. Finally, the pressure is released at a uniform speed, and the die casting machine drives the moving mold to move upward to open the mold. The formed casting is ejected through the ejection mechanism, completing the die casting of the conductor.

[0004] In the existing die-casting process for integrated cylindrical GIS aluminum alloy conductors, thermal expansion during mold operation alters the actual inner diameter of the core head seat. Variations in the dimensions of the sand core during batch molding and cumulative deviations in the coaxiality of the moving and fixed molds during mold closing all contribute to the sand core's inability to remain stably centered in the cavity after mold closing, resulting in radial offset and deflection, ultimately causing uneven annular wall thickness in the casting. Simultaneously, when the coaxiality between the sand core and the cavity deviates, the clamping force of the moving mold during mold closing exerts a hard pressure on the positioning cores at both ends of the sand core through the core head seat, easily leading to core head cracking and surface sand loss. After the detached sand particles enter the closed cavity, they are encapsulated by the molten aluminum during filling, forming solid inclusions. These inclusions have a significantly different dielectric constant from the aluminum alloy matrix, causing severe local electric field concentration in ultra-high voltage electric fields, directly leading to excessive partial discharge. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies and solve the aforementioned technical problems, this invention proposes an ultra-high voltage GIS aluminum alloy conductor forming device. Through a coaxial positioning assembly consisting of a vertical rod, a top core head seat, and a bottom core head seat, it provides rigid limiting for the sand core throughout the entire process, thereby avoiding radial displacement and deflection of the sand core. Specifically, the ultra-high voltage GIS aluminum alloy conductor forming device includes a low-pressure precision casting machine and a forming mold; the low-pressure precision casting machine is equipped with a riser pipe at its top. The low-pressure precision casting machine is installed at the bottom of the worktable, and the riser pipe extends to the upper surface of the worktable; the worktable is provided with a forming mold; the forming mold includes two opposing mold bases; Both mold bases are mounted on hydraulic mechanisms on opposite sides; both mold bases have cavities that extend through the bottom of the mold bases. A slide rail is provided between the two mold bases; a slide plate is provided inside the slide rail; blocks are fixed on both sides of the slide rail; a lead screw and a guide rod rotate between the two blocks, and the lead screw is driven by a motor; the lead screw and the guide rod pass through the slide plate and are slidably connected to the slide plate. Both sides of the slide plate are provided with drive blocks, and the drive blocks are driven by a lead screw and are slidably connected to the guide rod. Two bottom core holders are fixed on the slide plate, and the bottom core holders have grooves inside; a vertical rod is fixed inside the bottom core holder; and the top of the bottom core holders has evenly distributed pouring gates. One of the uprights is fitted with a sand core, and a sleeve is provided inside the sand core, and the sleeve is fitted onto the upright; and the core head at the bottom of the sand core is located in the groove of the bottom core head seat; The top of the sand core is provided with a top core head seat, and the top of the top core head seat is also provided with a groove, and the core head of the sand core is located in the groove of the top core head seat; the top core head seat is sleeved on the upright.

[0006] In a preferred embodiment of the present invention, a threaded post is fixed to the top of the upright; The threaded post is threaded with a locking nut, which is used to lock the top core head seat. Both mold bases have notches on their opposite sides at the top of the cavity; the top of the cavity of both mold bases is designed with rounded corners.

[0007] In a preferred embodiment of the present invention, each of the two opposing slots of the mold base is provided with a corresponding fixing component, and the two fixing components are staggered vertically. The fixing component includes two opposing upright plates, and the two upright plates of the two fixing components are opposite each other and staggered vertically; Both of the uprights have rounded corners on opposite sides.

[0008] As a preferred embodiment of the present invention, grooves are provided on opposite sides of both upright plates; An arc-shaped block is provided between the two upright plates, and the two sides of the arc-shaped block slide in the groove; an upright rod is fixed on the arc-shaped block, and the crossbar slides in the mold base; A spring is fitted onto the crossbar, and the other side of the spring is connected to a notch.

[0009] In a preferred embodiment of the present invention, the upright is a rectangular pole; The inner cavity of the sleeve is rectangular and is fitted onto the upright.

[0010] In a preferred embodiment of the present invention, two limiting blocks are fixed to the top of the sleeve; A limiting groove is provided on the top core head seat, and a limiting block is inserted in the limiting groove; the limiting block does not extend to the upper surface of the top core head seat.

[0011] As a preferred embodiment of the present invention, both of the limiting blocks are provided with lifting holes.

[0012] In a preferred embodiment of the present invention, circular grooves are provided on both sides of the top core head seat, and the circular grooves penetrate the top core head seat. The top of the cavities of the two mold bases are provided with guide grooves in the inner wall of the mold bases; each of the two guide grooves is provided with a conduit on the opposite side, and the conduit is connected to an external air pump. The bottom of the guide groove has a connecting hole. When the mold base is closed, the connecting hole corresponds to the circular groove. An electric push rod is installed above the connecting hole, and a plunger is fixed on the electric push rod. The plunger is initially located inside the guide groove.

[0013] In a preferred embodiment of the present invention, a semi-circular groove is provided at the bottom of the cavity; The outer diameter of the bottom core head seat is the same as the diameter of the semi-circular groove; Both drive blocks are at a certain distance from the slide plate.

[0014] The beneficial effects of this invention are as follows: 1. The ultra-high voltage GIS aluminum alloy conductor forming device of the present invention provides rigid limiting for the sand core throughout the entire process through the coaxial positioning assembly composed of the upright rod, the top core head seat and the bottom core head seat, thereby avoiding radial displacement and deflection of the sand core. It can ensure that the sand core is always stably located in the center of the cavity after mold closing, ensuring that the annular wall thickness of the casting is uniform and consistent. It avoids the problems of coaxial cylindrical electric field structure damage, conductor surface electric field distortion and local field strength exceeding the standard caused by uneven wall thickness. At the same time, it eliminates the solidification heat point displacement and internal shrinkage porosity defects caused by uneven wall thickness, ensures the uniformity of the flow cross section of the casting, and eliminates the hidden dangers of excessive temperature rise under long-term rated conditions, conductor melting and structural fracture during power grid short circuit faults.

[0015] 2. The ultra-high voltage GIS aluminum alloy conductor forming device of the present invention ensures that the mold base does not directly contact the sand core during the mold closing process, thereby avoiding the sand core being squeezed by the mold base. At the same time, since the sand core is located in the center of the cavity, it also avoids the mold base from hard squeezing the offset sand core, which would cause the core head to crack and the surface sand to fall off. It eliminates the hidden danger of sand particles entering the cavity and being wrapped by aluminum liquid to form solid inclusions, and avoids the problems of local electric field concentration and excessive partial discharge caused by micron-level inclusions. At the same time, the top core head seat is locked and fixed by the locking nut, thereby locking and fixing the sand core, which can prevent the sand core from floating during the casting process.

[0016] 3. The ultra-high voltage GIS aluminum alloy conductor forming device of the present invention pre-extracts the cavity to a negative pressure state after mold closing. On the one hand, it can expel the air inside the closed cavity and the gas volatilized by the resin binder in the sand core when heated, completely avoiding the problems of gas not being able to be discharged in time during the traditional filling process, being drawn into the aluminum liquid to form subcutaneous pores and diffuse pinholes, greatly improving the overall density and internal purity of the casting, and completely eliminating the hidden dangers of local electric field concentration and excessive partial discharge caused by micron-level pores. On the other hand, the negative pressure environment in the cavity can form a uniform auxiliary adsorption force on the molten aluminum alloy liquid, which works synergistically with the bottom-up filling pressure of the low-pressure precision casting machine, so that the aluminum liquid fills more smoothly and uniformly from bottom to top along the annular gap between the sand core and the cavity. The filling linear speed is controllable throughout the process, with no turbulence, no splashing, and no liquid surface rolling, completely avoiding the secondary oxidation inclusion defects caused by the contact between the aluminum liquid and air, and at the same time greatly improving the filling fluidity of the aluminum liquid. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is a state diagram of the forming device of the present invention before mold closing; Figure 2 This is a diagram showing the state of the forming device of the present invention after mold closing; Figure 3 This is a diagram showing the installation state of the slide plate, bottom core head, sand core, and top core head in this invention; Figure 4 This is the present invention. Figure 3 Enlarged view of a section at point A in the middle; Figure 5 This is a structural diagram of the worktable and mold base in this invention; Figure 6 This is a structural diagram of the upright plate and the arc-shaped block in this invention; Figure 7 This is the present invention. Figure 2 Top view; Figure 8 This is the present invention. Figure 7 Sectional view at point BB; Figure 9 This is the present invention. Figure 8 Enlarged view of a section at point C; Figure 10 This is the present invention. Figure 8 Enlarged view of a section at point D; Figure 11 This is the present invention. Figure 8 Enlarged view of a section at point E in the middle.

[0019] In the diagram: 1. Workbench; 11. Lifting pipe; 12. Slide rail; 13. Slide plate; 14. Stop block; 15. Lead screw; 16. Drive block; 2. Mold base; 21. Notched groove; 22. Semi-circular groove; 3. Bottom core seat; 31. Vertical rod; 32. Sprue; 33. Top core seat; 331. Circular groove; 34. Threaded column; 35. Locking nut; 4. Sand core; 41. Sleeve; 42. Limiting block; 43. Limiting groove; 44. Lifting hole; 5. Vertical plate; 51. Slide groove; 52. Arc block; 53. Horizontal bar; 6. Guide groove; 61. Guide tube; 62. Connecting hole; 63. Electric actuator; 64. Plunger. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0021] like Figures 1 to 11As shown, the ultra-high voltage GIS aluminum alloy conductor forming device of the present invention includes a low-pressure precision casting machine and a forming mold; the top of the low-pressure precision casting machine is provided with a riser pipe 11; the low-pressure precision casting machine is installed at the bottom of the workbench 1, and the riser pipe 11 extends to the upper surface of the workbench 1; the workbench 1 is provided with a forming mold; the forming mold includes two opposing mold bases 2; the opposite sides of the two mold bases 2 are both installed on a hydraulic mechanism; each of the two mold bases 2 has a cavity, and the cavity penetrates the bottom of the mold base 2; a slide 12 is provided between the two mold bases 2; the slide 12 is provided with... The slide 13 has a slide plate 13; both sides of the slide 12 are fixed with blocks 14; a lead screw 15 and a guide rod rotate between the two blocks 14, and the lead screw 15 is driven by a motor; the lead screw 15 and the guide rod pass through the slide plate 13 and are slidably connected to the slide plate 13; both sides of the slide plate 13 are provided with drive blocks 16, and the drive blocks 16 are helically driven with the lead screw 15 and slidably connected to the guide rod; two bottom core head seats 3 are fixed on the slide plate 13, and the bottom core head seats 3 have grooves; a vertical rod 31 is fixed in the bottom core head seat 3; the top of the bottom core head seat 3 has uniformly arranged pouring gates 32.

[0022] One of the uprights 31 is fitted with a sand core 4, and a sleeve 41 is provided inside the sand core 4, and the sleeve 41 is fitted onto the upright 31; the core head at the bottom of the sand core 4 is located in the groove of the bottom core head seat 3; the top of the sand core 4 is provided with a top core head seat 33, and the top of the top core head seat 33 is also provided with a groove, and the core head at the top of the sand core 4 is located in the groove of the top core head seat 33; the top core head seat 33 is fitted onto the upright 31.

[0023] In this embodiment, a threaded post 34 is fixed to the top of the upright 31; a locking nut 35 is threaded onto the threaded post 34, and the locking nut 35 is used to lock the top core seat 33; a notch 21 is opened on the top of the cavity on the opposite side of the two mold bases 2; the top of the mold cavity of the two mold bases 2 is rounded.

[0024] First, the sleeve 41 inside the sand core 4 is coaxially fitted onto the corresponding upright 31, so that the core head at the bottom of the sand core 4 is precisely embedded in the groove of the bottom core head seat 3 to complete the lower end pre-positioning. Then, the top core head seat 33 is coaxially fitted onto the top of the upright 31, so that the core head at the top of the sand core 4 is embedded in the groove of the top core head seat 33. The locking nut 35 on the threaded post 34 at the top of the upright 31 is engaged and locked, so that the top core head seat 33 is firmly pressed and fixed, so that the upper and lower core head seats are completely in contact with the core heads at both ends of the sand core 4, forming a coaxial positioning assembly composed of the upright 31, the upper and lower core head seats, and the sand core 4. The upright 31 provides radial and axial limit for the sand core 4 throughout its entire range, ensuring the verticality and coaxial reference of the sand core 4 from the source, and preventing the sand core 4 from going out of bounds. The inherent deviations of tilting and deflection are eliminated. After the assembly of the sand core 4 positioning assembly is completed, the floating sand and impurities on the surface of the sand core 4 are cleaned to prevent sand particles from falling into the molding cavity. Then, the motor drives the lead screw 15 to rotate, which drives the drive block 16, which is screw-driven with the lead screw 15, to move along the guide rod. This pushes the slide plate 13 to move along the slide rail 12 to the middle position of the two oppositely arranged mold bases 2. At the same time, the entire sand core 4 positioning assembly moves to the mold closing position. When the drive block 16 is in contact with the corresponding stop block 14, the sand core 4 positioning assembly stops precisely at the mold closing center of the two mold bases 2. The pouring port 32 on the bottom core head seat 3 is completely aligned and connected with the riser pipe 11 of the low-pressure precision casting machine under the workbench 1, completing the position calibration before mold closing.

[0025] Specifically, the hydraulic mechanism then drives the two opposing mold bases 2 to move synchronously towards each other to close the mold. During the mold closing process, the semi-cavities of the two mold bases 2 gradually surround the sand core 4 positioning assembly. The rounded corner structure of the cavity port can achieve smooth guidance and avoid rigid collision between the mold base 2 and the sand core 4. When the mold is closed, the inner wall of the cavity will first contact the side of the top core head seat 33 or the bottom core head seat 3, thereby avoiding the mold base 2 directly acting on the sand core 4, which would cause the sand core 4 to fall off when the mold base 2 contacts the sand core 4.

[0026] More specifically, after the mold is closed, the two mold bases 2's semi-cavities are completely closed to form a complete molding cavity. A uniform annular casting cavity is formed between the sand core 4 and the inner wall of the cavity. Then, the low-pressure precision casting machine is started for casting. The molten electrical grade aluminum alloy liquid is driven by a constant pressure under closed-loop control and is smoothly injected into the pouring port 32 of the bottom core head seat 3 through the riser pipe 11. Then, it is evenly distributed into the annular casting cavity. The aluminum liquid smoothly fills the outer wall of the sand core 4 layer by layer from bottom to top. The filling line speed is strictly controlled throughout the process, with no turbulence, no air entrapment, and no secondary oxidation, until the entire casting cavity is completely filled. After filling, a constant holding pressure is continuously applied for forced shrinkage to offset the volume shrinkage during the solidification process of the aluminum alloy until the casting is completely solidified, completing the precision molding of the integrated straight cylindrical GIS aluminum alloy conductor.

[0027] Furthermore, after the aluminum alloy conductor cools and forms, the control mold bases 2 are closed together, and the sliding plate 13 is controlled to gradually move the sand core 4 and the formed conductor out of the two mold bases 2. After the mold bases 2 are moved out, the sand core 4 and the formed conductor can be removed. At the same time, during the casting of the aluminum alloy conductor, the sand core 4 can be fitted onto the upright 31 of another bottom core head seat 3, and the top core head seat 33 can be fixed on the sand core 4. When the casting is completed and the cast conductor is removed, the bottom core head seat 3 with the sand core 4 can be moved between the two mold bases 2, and then the casting can continue. This can reduce the time for installing the sand core 4 and removing the conductor, and improve work efficiency.

[0028] Furthermore, the coaxial positioning assembly consisting of the upright rod 31, the top core head seat 33, and the bottom core head seat 3 provides rigid positioning for the sand core 4 throughout the entire process, thereby preventing radial offset and deflection of the sand core 4. This ensures that the sand core 4 remains stably located in the center of the cavity after mold closing, ensuring uniform annular wall thickness of the casting. It avoids the problems of coaxial cylindrical electric field structure damage, conductor surface electric field distortion, and local field strength exceeding the standard caused by uneven wall thickness. At the same time, it eliminates solidification heat point offset and internal shrinkage defects caused by uneven wall thickness, ensuring the uniformity of the flow cross section of the casting and eliminating the hidden dangers of excessive temperature rise under long-term rated conditions, conductor melting, and structural fracture during power grid short circuit faults.

[0029] Meanwhile, during the mold closing process, the mold base 2 will not directly contact the sand core 4, thus avoiding the sand core 4 being squeezed by the mold base 2. Also, since the sand core 4 is located in the center of the cavity, it also avoids the mold base 2 from hard squeezing the offset sand core 4, which would cause the core head of the sand core 4 to crack and the surface sand to fall off. This eliminates the hidden danger of sand particles entering the cavity and being wrapped by the aluminum liquid to form solid inclusions, and avoids the problems of local electric field concentration and excessive partial discharge caused by micron-level inclusions. At the same time, the top core head seat 33 is locked and fixed by the locking nut 35, thereby locking and fixing the sand core 4, thus preventing the sand core 4 from floating during the casting process.

[0030] As an embodiment of the present invention; each of the two mold bases 2 has a corresponding fixing component in the corresponding notch 21, and the two fixing components are staggered vertically; the fixing component includes two opposing upright plates 5, and the two upright plates 5 of the two fixing components are opposite to each other and staggered vertically; the opposing sides of the two upright plates 5 are both rounded.

[0031] In this embodiment, each of the two upright plates 5 has a sliding groove 51 on one side opposite to the other; an arc-shaped block 52 is provided between the two upright plates 5, and the two sides of the arc-shaped block 52 slide in the sliding groove 51; an upright rod 31 is fixed on the arc-shaped block 52, and a crossbar 53 slides in the mold base 2; a spring is sleeved on the crossbar 53, and the other side of the spring is connected in the notch 21.

[0032] During the synchronous movement of the two mold bases 2 towards each other to close the mold, the fixed components arranged vertically and horizontally in the notch 21 of the mold base 2 move synchronously towards the threaded column 34. As the mold closing stroke continues to advance, the threaded column 34 gradually extends into the space between the opposing vertical plates 5 of the two sets of fixed components. The rounded corner structure on the opposite side of the vertical plate 5 can achieve smooth guidance and avoid rigid collision with the threaded column 34. The vertical plates 5 arranged vertically and horizontally form a preliminary limit from the upper and lower sides of the threaded column 34 and the radial relative direction, forming a pre-constraint on the radial degree of freedom of the threaded column 34, and then forming a radial limit on the entire sand core 4 through the vertical rod 31. Specifically, as the mold closing stroke progresses further, the inner arc surface of the arc block 52 between the outer wall of the threaded column 34 and the vertical plate 5 makes smooth contact. The continuous opposing movement of the mold base 2 causes the threaded column 34 to form a reverse resistance against the arc block 52, pushing the arc block 52 to slide adaptively along the slide groove 51 on the vertical plate 5. At the same time, it drives the crossbar 53 fixed to the arc block 52 to slide into the mold base 2, compressing the spring sleeved on the crossbar 53. The elastic reaction force of the spring is evenly applied to the outer wall of the threaded column 34 through the arc block 52. The two sets of arc blocks, which are staggered vertically, act as a result. 52 forms a floating ring clamping on the threaded column 34 from four radial directions, continuously applying a uniform radial constraint force to the threaded column 34 throughout the mold closing process. In turn, the upright 31, the top core head seat 33, and the bottom core head seat 3 form a coaxial limit for the sand core 4 throughout its full stroke, completely eliminating the radial movement and shaking of the sand core 4 during the mold closing process, and preventing the sand core 4 from shaking and causing the top core head seat 33 to hit the cavity of the mold base 2. This also prevents the sand core 4 from shaking and causing the top core head seat 33 to hit the inner wall of the cavity, resulting in sand falling off the surface of the sand core 4 and core head cracking.

[0033] As an embodiment of the present invention; the upright 31 is a rectangular rod; the inner cavity of the sleeve 41 is rectangular and is sleeved on the upright 31; two limiting blocks 42 are fixed at the top of the sleeve 41; a limiting groove 43 is opened on the top core seat 33, and the limiting blocks 42 are inserted in the limiting groove 43; the limiting blocks 42 do not extend to the upper surface of the top core seat 33.

[0034] In this embodiment, each of the two limiting blocks 42 is provided with a lifting hole 44; both sides of the top core head seat 33 are provided with a circular groove 331, and the circular groove 331 penetrates the top core head seat 33; the top of the cavity of each of the two mold bases 2 is provided with a guide groove 6 in the inner wall of the mold base 2; each of the two guide grooves 6 is provided with a guide tube 61 on the opposite side, and the guide tube 61 is connected to an external air pump.

[0035] The bottom of the guide groove 6 is provided with a connecting hole 62. When the mold base 2 is closed, the connecting hole 62 corresponds to the circular groove 331. An electric push rod 63 is installed above the connecting hole 62, and a plunger 64 is fixed on the electric push rod 63. The plunger 64 is initially located in the guide groove 6.

[0036] Since the upright 31 adopts a rectangular rod structure, the inner cavity of the sleeve 41 inside the sand core 4 is a rectangular cross section that is perfectly adapted to the upright 31. When the sand core 4 is sleeved on the upright 31 through the sleeve 41, the circumferential rotation of the sleeve 41 is restricted. Since there are two symmetrically arranged limiting blocks 42 fixed at the top of the sleeve 41, and the top core head seat 33 is provided with limiting grooves 43 that correspond one-to-one with the limiting blocks 42, when installing the top core head seat 33, the limiting grooves 43 and the limiting blocks 42 are precisely aligned and the limiting blocks 42 are completely embedded in the limiting grooves 43, which completely avoids the circumferential rotation and radial displacement of the top core head seat 33 during the tightening of the locking nut 35. At the same time, through the precise alignment of the limiting blocks 42 and the limiting grooves 43, the circumferential position of the through circular grooves 331 on both sides of the top core head seat 33 can be uniquely locked, ensuring that the circular grooves 331 can be precisely aligned with the corresponding structure on the inner wall of the mold base 2 after the mold is closed. Specifically, after the two mold bases 2 are closed, the circular grooves 331 on both sides of the top core head seat 33 are precisely aligned with the connecting holes 62 at the bottom of the corresponding guide grooves 6, forming a complete air path from the inside of the closed cavity to the external air pump. Before starting the casting process, the external air pump is started first, and the gas in the guide groove 6 is continuously extracted through the conduit 61. Then, the air in the closed cavity and the volatile gas adsorbed on the surface of the sand core 4 are completely extracted through the connecting holes 62 and the circular grooves 331, so that a stable negative pressure state is formed in the cavity. When the vacuum degree in the cavity reaches the preset process requirements, the electric push rod 63 is extended, driving the plunger 64 to move downward, passing through the connecting holes 62 and inserting into the circular grooves 331 of the top core head seat 33, until the bottom end face of the plunger 64 is completely flush with the bottom end face of the circular groove 331, which not only completely seals the air extraction path, but also ensures the integrity and smoothness of the inner wall of the cavity. Then, the low-pressure precision casting machine can be started to perform the aluminum liquid casting operation. More specifically, after the casting has completely solidified and the mold base 2 is opened, the motor drives the lead screw 15 to rotate, which drives the forming conductor, sand core 4 and top core head seat 33 on the slide plate 13 to move away from the mold base 2 as a whole. Then, the locking nut 35 is unscrewed from the threaded post 34 at the top of the upright 31, and the hook of the lifting tool is hung in the lifting hole 44 of the limit block 42. The sand core 4 and the forming conductor can be smoothly removed from the upright 31 by the lifting equipment, thus completing the non-destructive demolding and transfer of the casting. Furthermore, after mold closing, the cavity is pre-extracted to a negative pressure state. On the one hand, this can expel the air inside the closed cavity, as well as the gas volatilized by the resin binder in the sand core when heated. This completely avoids the problems of gas not being able to be discharged in time during the traditional filling process, being drawn into the aluminum liquid and forming subcutaneous pores and diffuse pinholes. This significantly improves the overall density and internal purity of the casting, and completely eliminates the hidden dangers of local electric field concentration and excessive partial discharge caused by micron-level pores. On the other hand, the negative pressure environment in the cavity can form a uniform auxiliary adsorption force on the molten aluminum alloy liquid, which works synergistically with the bottom-up filling pressure of the low-pressure precision casting machine. This allows the aluminum liquid to fill more smoothly and uniformly from bottom to top along the annular gap between the sand core 4 and the cavity. The filling linear speed is controllable throughout the process, with no turbulence, no splashing, and no liquid surface rolling. This completely avoids the secondary oxidation inclusion defects caused by the aluminum liquid contacting the air, and at the same time significantly improves the filling fluidity of the aluminum liquid.

[0037] As an embodiment of the present invention, a semi-circular groove 22 is provided at the bottom of the cavity; the outer diameter of the bottom core head seat 3 is the same as the diameter of the semi-circular groove 22; and there is a certain distance between the two drive blocks 16 and the slide plate 13.

[0038] When the motor drives the lead screw 15 to rotate in the forward direction, the lead screw 15 drives the two drive blocks 16 to move synchronously along the guide rod. One drive block 16 gradually moves closer to the slide plate 13 until it is completely in contact with the side wall of the slide plate 13, while the other drive block 16 moves synchronously away from the slide plate 13, further widening the gap between it and the slide plate 13. Subsequently, the slide plate 13, the upright 31 fixed on the slide plate 13, the bottom core head seat 3, and the assembled sand core 4 and top core head seat 33 are pushed as a whole to move towards the mold closing position between the two mold bases 2. When the drive block 16 on the side away from the slide plate 13 is in contact with the corresponding stop block 14, the lead screw 15 stops rotating. At this time, the sand core 4 and the upright rod 31 are pre-stopped in the mold closing position between the two mold bases 2, completing the pre-positioning. Then the motor drives the lead screw 15 to rotate in the opposite direction, driving the two drive blocks 16 to move synchronously in the opposite direction. The drive blocks 16 that were originally in contact with the slide plate 13 gradually move away from the slide plate 13, and finally the slide plate 13 is placed between the two drive blocks 16, and a uniform gap is maintained between the two sides of the slide plate 13 and the two drive blocks 16. When the two mold bases 2 close together, the mold cavity will first contact the top core head seat 33 and the bottom core head seat 3. As the two mold bases 2 continue to close and advance, the top core head seat 33 will be pushed to adaptively translate and calibrate. Then, through the upright 31 and the top core head seat 33, the sand core 4 and the slide plate 13 will be adjusted synchronously along the slide 12 until the bottom core head seat 3 is completely embedded in the complete circular limiting groove 43 formed after the two semi-circular grooves 22 are closed. At this time, the sand core 4 is accurately positioned on the central axis of the complete cavity after the mold is closed, completing the final accurate coaxial positioning. This avoids the pre-positioning deviation of the sand core 4 caused by the cumulative error of the transmission mechanism and the translation deviation of the station, and fundamentally avoids the problems of mold closing squeezing of the sand core 4 and radial deflection of the sand core 4 caused by inaccurate pre-positioning.

[0039] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing the present invention and simplifying the description only, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and should not be construed as indicating or implying relative importance.

[0040] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-high voltage GIS aluminum alloy conductor forming device, comprising a low-pressure precision casting machine and a forming mold; the low-pressure precision casting machine is provided with a riser pipe (11) at the top; Its features are, The low-pressure precision casting machine is installed at the bottom of the workbench (1), and the riser pipe (11) extends to the upper surface of the workbench (1); the workbench (1) is provided with a forming mold; the forming mold includes two opposing mold bases (2); Both mold bases (2) are mounted on hydraulic mechanisms on opposite sides; both mold bases (2) have cavities inside, and the cavities penetrate the bottom of the mold bases (2); A slide rail (12) is provided between the two mold bases (2); a slide plate (13) is provided inside the slide rail (12); a stop block (14) is fixed on both sides of the slide rail (12); a lead screw (15) and a guide rod rotate between the two stop blocks (14), and the lead screw (15) is driven by a motor; the lead screw (15) and the guide rod pass through the slide plate (13) and are slidably connected to the slide plate (13); Both sides of the slide plate (13) are provided with drive blocks (16), and the drive blocks (16) are screwed to the lead screw (15) and slidably connected to the guide rod; Two bottom core head seats (3) are fixed on the slide plate (13), and the bottom core head seats (3) are provided with grooves; a vertical rod (31) is fixed in the bottom core head seat (3); and the top of the bottom core head seat (3) is provided with uniformly arranged pouring gates (32); One of the uprights (31) is fitted with a sand core (4), and a sleeve (41) is provided inside the sand core (4), and the sleeve (41) is fitted on the upright (31); The top of the sand core (4) is provided with a top core head seat (33), and the top of the top core head seat (33) is also provided with a groove; the top core head seat (33) is sleeved on the upright (31); Both mold bases (2) have notches (21) on their opposite sides at the top of the cavity; the top of the cavity of both mold bases (2) is rounded. Each of the two mold bases (2) has a corresponding fixing component in its opposite slot (21), and the two fixing components are staggered vertically. The fixing component includes two opposing upright plates (5), and the two upright plates (5) of the two fixing components are opposite to each other and staggered vertically; Both of the two upright plates (5) have rounded corners on opposite sides; Each of the two upright plates (5) has a groove (51) on one side opposite to the other; An arc-shaped block (52) is provided between the two upright plates (5), and the two sides of the arc-shaped block (52) slide in the groove (51); a vertical rod (31) is fixed on the arc-shaped block (52), and a horizontal rod (53) slides in the mold base (2); A spring is fitted on the crossbar (53), and the other side of the spring is connected to the notch (21); The top core head seat (33) has circular grooves (331) on both sides, and the circular grooves (331) penetrate the top core head seat (33); The top of the cavity of the two mold bases (2) is provided with guide grooves (6) in the inner wall of the mold base (2); the two guide grooves (6) are provided with conduits (61) on opposite sides, and the conduits (61) are connected to an external air pump; The bottom of the guide groove (6) is provided with a connecting hole (62). When the mold base (2) is closed, the connecting hole (62) corresponds to the circular groove (331). An electric push rod (63) is installed above the connecting hole (62), and a plunger (64) is fixed on the electric push rod (63). The plunger (64) is initially located in the guide groove (6).

2. The ultra-high voltage GIS aluminum alloy conductor forming device according to claim 1, characterized in that: A threaded post (34) is fixed to the top of the upright (31); The threaded post (34) is threaded with a locking nut (35), and the locking nut (35) is used to lock the top core seat (33).

3. The ultra-high voltage GIS aluminum alloy conductor forming device according to claim 1, characterized in that: The upright (31) is a rectangular rod; The inner cavity of the sleeve (41) is rectangular and is fitted onto the upright (31).

4. The ultra-high voltage GIS aluminum alloy conductor forming device according to claim 3, characterized in that: Two limiting blocks (42) are fixed to the top of the sleeve (41); A limiting groove (43) is provided on the top core head seat (33), and a limiting block (42) is inserted in the limiting groove (43); the limiting block (42) does not extend to the upper surface of the top core head seat (33).

5. The ultra-high voltage GIS aluminum alloy conductor forming device according to claim 4, characterized in that: Both of the limiting blocks (42) are provided with lifting holes (44).

6. The ultra-high voltage GIS aluminum alloy conductor forming device according to claim 1, characterized in that: A semi-circular groove (22) is provided at the bottom of the cavity; the outer diameter of the bottom core head seat (3) is the same as the diameter of the semi-circular groove (22); there is a certain distance between the two drive blocks (16) and the slide plate (13).

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