A forming stabilizing device for ultra extra high voltage GIS aluminum alloy conductor

Abstract

The present application relates to metal low-pressure casting forming auxiliary equipment technical field, specifically to a kind of forming stabilizing device for super-high voltage GIS aluminum alloy conductor, for with low-pressure casting equipment cooperation use, low-pressure casting equipment includes casting mould and pressure maintaining gas circuit, sand core in casting mould includes sand core core bone outer stretch section that stretches out casting mould, comprising: setting in the outside of casting mould external frame, external frame is equipped with stabilizing ring seat in the axial position of forming avoidance passage;Stabilizing ring seat is equipped with pressure maintaining pressure-taking pressure stabilizing mechanism, and the pressure-taking side of pressure maintaining pressure-taking pressure stabilizing mechanism is used to communicate with pressure maintaining gas circuit.Compared with prior art, the present application is by setting external frame and stabilizing ring seat outside casting mould, and by pressure-taking diaphragm cavity, axial pressure ring, wedge-shaped push ring, stabilizing slider and arc-shaped pressure claw form pressure maintaining pressure-taking radial pressure stabilizing structure, so that sand core core bone outer stretch section is automatically generated radial self-centering holding force by the same process pressure after low-pressure casting pressure maintaining gas circuit pressure rise.

Description

Technical Field

[0001] This invention relates to the field of auxiliary equipment for low-pressure metal casting, and more particularly to a forming stabilizing device for ultra-high voltage GIS aluminum alloy conductors. Background Technology

[0002] Ultra-high voltage GIS aluminum alloy conductors typically feature long lengths, through-hole structures, high dimensional accuracy requirements for end connection areas, and limited machining allowances for conductive contact surfaces. During low-pressure casting, a sand core is generally required within the casting mold to form the conductor's internal cavity. For slender hollow conductors, the sand core or its end positioning structure is simultaneously affected by the buoyancy of the molten aluminum, the impact of filling, the thermal expansion of the mold, and the thermal deformation of the sand core itself during the liquid-lifting, filling, pressurizing, and holding-pressure crystallization stages. If the extended section of the sand core lacks stable support outside the mold, minute misalignments that are difficult to observe visually but can affect the coaxiality of the casting's inner hole and the uniformity of local wall thickness can easily occur. The announcement number CN102211167B discloses a mold and preparation method for aluminum alloy conductor castings. Its technical focus is on the setting of metal mold, sand core, venting rope, chill, sprue, ingate, and low-pressure casting stage. It can improve the process yield and microstructure density of low-pressure casting of aluminum alloy conductors. However, this type of solution still mainly focuses on mold structure and casting process, and does not establish an independent mechanical stability benchmark for the dynamic displacement of the sand core core extension outside the casting mold.

[0003] A pre-tightening device for sand cores, with announcement number CN102248131A, connects to the core via a shaft, connector, two load-bearing plates, a pre-tightening spring, and a nut. The pre-tightening spring deforms to generate a continuous pre-tightening force, thereby enhancing the rigidity of the slender sand core. This design illustrates the technical significance of auxiliary stabilization of the sand core on the outside of the sand box or mold. However, its stabilization method primarily involves applying axial tension along the length of the core. The pre-tightening force is determined manually by adjusting the nut and spring deformation. It cannot automatically change with the process pressure during the low-pressure casting stages of liquid rise, filling, and holding pressure crystallization, nor can it form a self-centering grip around the conductor forming axis in the radial direction of the extended section of the sand core. For long-axis hollow castings such as ultra-high voltage GIS aluminum alloy conductors, what truly affects the coaxiality and wall thickness consistency of the conductor's inner hole is often the radial offset of the extended section of the sand core during the pressure holding stage, rather than simply insufficient axial tension. Therefore, an external forming stabilizing device is still needed that can automatically generate radial stabilizing force using the pressure of the low-pressure casting pressure holding air circuit without altering the casting mold body. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a forming stabilizing device for ultra-high voltage GIS aluminum alloy conductors, in order to solve the problem that in the existing low-pressure casting process of aluminum alloy conductors, the extended section of the sand core is prone to radial micro-displacement under the action of holding pressure and aluminum liquid buoyancy, and the existing mold-side chills, venting or axial spring pre-tightening structures are difficult to form a radial self-centering stabilizing force that automatically changes with the casting pressure outside the mold.

[0005] To achieve the above objectives, this invention provides a forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors, used in conjunction with low-pressure casting equipment. The low-pressure casting equipment includes a casting mold and a pressure-holding air circuit. The sand core within the casting mold includes an extended section of the sand core core extending out of the casting mold. The device includes: an external frame disposed outside the casting mold, the external frame forming a forming clearance channel extending along the conductor forming axis, and a stabilizing ring seat coaxial with and spaced from the outer wall of the casting mold at an axial position of the forming clearance channel; the stabilizing ring seat is provided with a pressure-holding and pressure-taking pressure... The stabilizing mechanism includes a pressure-tapping diaphragm cavity, an axial pressure ring, a wedge-shaped push ring, and several circumferentially distributed stabilizing sliders. The diaphragm in the pressure-tapping diaphragm cavity divides it into a pressure-tapping side and an execution side. The pressure-tapping side is connected to the pressure-holding air circuit through a pressure-tapping connector. The execution side pushes the axial pressure ring to move axially through a force-transmitting push rod. The wedge-shaped push ring moves with the axial pressure ring and engages with the inclined surfaces of each stabilizing slider to push each stabilizing slider to move synchronously towards the center. This, in turn, stabilizes the extended section of the sand core or the positioning sleeve fitted on its outer side through the arc-shaped pressure claw.

[0006] Preferably, the external frame is provided with a longitudinal bearing beam parallel to the forming avoidance channel, an adjustable base is slidably disposed on the longitudinal bearing beam, the stabilizing ring seat is fixed on the adjustable base, and a locking member is provided between the adjustable base and the longitudinal bearing beam. The locking member is used to fix the adjustable base on the longitudinal bearing beam after the stabilizing ring seat is adjusted to a predetermined position along the conductor forming axis.

[0007] Preferably, the pressure holding and pressure tapping stabilizing mechanism includes a pressure tapping diaphragm cavity disposed on one axial side of the stabilizing ring seat. The pressure tapping end of the pressure tapping diaphragm cavity is provided with a pressure tapping connector, which is used to communicate with the pressure holding gas path. A diaphragm sheet is disposed inside the pressure tapping diaphragm cavity, which divides the pressure tapping diaphragm cavity into a pressure tapping side close to the pressure tapping connector and an execution side away from the pressure tapping connector.

[0008] Preferably, the stabilizing ring seat is provided with an annular guide cavity, and an axial pressure ring is slidably disposed in the annular guide cavity; a force transmission push rod is provided on the execution side of the pressure tapping diaphragm cavity, the force transmission push rod abuts against the axial pressure ring, and a wedge-shaped push ring is provided on the inner side of the axial pressure ring; a return spring is sleeved on the outer side of the force transmission push rod, one end of the return spring abuts against the pressure tapping diaphragm cavity or the stabilizing ring seat, and the other end abuts against the axial pressure ring or a spring stop connected to the force transmission push rod, for driving the axial pressure ring to return to its original position after the pressure tapping diaphragm cavity is depressurized.

[0009] Preferably, the stabilizing ring seat has a plurality of radial grooves arranged radially, and a stabilizing slider is slidably arranged in the radial grooves. The end of the stabilizing slider facing the wedge-shaped push ring has a mating inclined surface, and the end of the stabilizing slider facing the center of the forming avoidance channel is connected to an arc-shaped pressure claw through a stabilizing claw seat. The wedge-shaped push ring and the mating inclined surface cooperate to push the stabilizing slider toward the center of the forming avoidance channel when the axial pressure ring moves axially.

[0010] Preferably, a throttling buffer valve is provided between the pressure tapping connector and the pressure holding gas path. The throttling buffer valve is used to limit the instantaneous gas flow between the pressure holding gas path and the pressure tapping side of the pressure tapping diaphragm cavity. The throttling buffer valve is provided with a pressure relief handle, which is used to connect the pressure tapping side of the pressure tapping diaphragm cavity to the outside.

[0011] Preferably, a plurality of radial grooves are distributed at equal angles around the axis of the forming avoidance channel, the radial grooves are T-shaped grooves or dovetail grooves, the stabilizing slider is a strip slider adapted to the T-shaped groove or dovetail groove, and the inclination angle of the mating inclined surface is 6° to 18°.

[0012] Preferably, the arc-shaped pressure claw is tile-shaped, and the side of the arc-shaped pressure claw facing the center of the forming avoidance channel forms a concave arc surface. A heat insulation pad is detachably provided on the concave arc surface. The heat insulation pad is a graphite pad, a ceramic fiber pad, or a heat-resistant composite pad. Both ends of the arc-shaped pressure claw form chamfered guide surfaces.

[0013] Preferably, the stabilizing claw seat is provided with a floating groove extending axially along the forming avoidance channel, a floating block is slidably disposed in the floating groove, the arc-shaped pressure claw is fixed on the floating block, disc springs are respectively abutted on both sides of the floating block, and a limit pin is provided on the stabilizing claw seat to limit the axial floating stroke of the floating block in the floating groove.

[0014] Preferably, the positioning sleeve is a split cylindrical sleeve fitted on the outside of the extended section of the sand core core. The positioning sleeve includes a first half sleeve and a second half sleeve that interlock with each other. The first half sleeve and the second half sleeve are connected by fasteners. The axial end of the positioning sleeve is provided with an end shoulder that cooperates with the axial limiting of the arc-shaped pressure claw.

[0015] The beneficial effects of this invention are:

[0016] This forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors uses an external frame and stabilizing ring seat set on the outside of the casting mold. It forms a pressure-holding and pressure-taking radial pressure stabilizing structure through a pressure-tapping diaphragm cavity, axial pressure ring, wedge-shaped push ring, stabilizing slider and arc-shaped pressure claw. This allows the extended section of the sand core to no longer rely solely on the core head inside the mold or artificial spring pre-tightening to maintain its position. Instead, after the pressure is increased in the low-pressure casting pressure-holding air circuit, the radial self-centering holding force is automatically generated by the same process pressure. The stabilizing force corresponds to the low-pressure casting pressure stage, thereby centrally solving the problem of reduced coaxiality and wall thickness uniformity of the conductor inner hole caused by radial micro-displacement of the sand core during the pressure-holding stage.

[0017] The pressure-holding air circuit is separated from the pressure-tapping side by a diaphragm and the force-transmitting push rod by an actuator. A throttling buffer valve is installed at the pressure tapping joint so that the pressure-holding air circuit only serves as a source of pressure signal and driving force, and does not exchange gas with the mechanical actuator areas where the axial pressure ring, wedge push ring, and stabilizing slider are located. This avoids contamination of the pressure-holding air circuit by external mechanical devices and also avoids pressure fluctuations in low-pressure casting caused by continuous air consumption by ordinary external cylinders, making the device safe and stable for use in the casting site.

[0018] By simultaneously applying the coaxial wedge-shaped push ring to the mating inclined surfaces of multiple stabilizing sliders, multiple arc-shaped pressure claws move synchronously towards the center around the positioning sleeve or the extended section of the sand core. The return spring and axial floating structure automatically release the pressure after decompression and make limited clearance during thermal expansion and contraction, thereby ensuring radial pressure stability while reducing the risk of cracking at the end of the sand core, core pulling, or jamming of the positioning sleeve caused by rigid clamping. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a three-dimensional structural diagram of the forming stabilizing device of the present invention in conjunction with the casting mold and the extended section of the sand core.

[0021] Figure 2This is a schematic diagram of the external frame, longitudinal bearing beam, adjustable base, and stabilizing ring of the present invention.

[0022] Figure 3 This is a schematic diagram of the main structure of the stabilizing ring seat of the present invention with the arc-shaped pressure claw in the open state;

[0023] Figure 4 This is a front view schematic diagram of the arc-shaped pressure claw in the stabilizing ring seat of the present invention in a holding state;

[0024] Figure 5 This is a cross-sectional structural schematic diagram showing the cooperation relationship between the pressure-taking diaphragm cavity, the force-transmitting push rod, the axial pressure ring, and the wedge-shaped push ring of the present invention;

[0025] Figure 6 This is a partial cross-sectional structural schematic diagram showing the fit between the wedge-shaped push ring, the mating inclined surface, the stabilizing slider, and the radial groove of the present invention;

[0026] Figure 7 This is an exploded structural diagram of the stabilizing claw seat, floating groove, floating block, disc spring, arc-shaped pressure claw, and heat insulation pad of the present invention.

[0027] Figure 8 This is a cross-sectional structural diagram showing the engagement state of the positioning sleeve and the extended section of the sand core in this invention.

[0028] The markings in the diagram are as follows: 1. External frame; 2. Forming clearance channel; 3. Longitudinal bearing beam; 4. Adjustable base; 5. Locking element; 6. Stabilizing ring seat; 7. Annular guide cavity; 8. Axial pressure ring; 9. Pressure tapping diaphragm cavity; 10. Pressure tapping connector; 11. Diaphragm; 12. Force transmission push rod; 13. Wedge-shaped push ring; 14. Radial slide groove; 15. Stabilizing slider; 16. Mating inclined surface; 17. Stabilizing claw seat; 18. Arc-shaped pressure claw; 19. Heat insulation pad; 20. Positioning sleeve; 21. First half-set; 22. Second half-set; 23. End shoulder; 24. Floating groove; 25. Floating block; 26. Disc spring; 27. Limiting pin; 28. Return spring; 29. ​​Throttling buffer valve; 30. Pressure relief handle; A. Casting mold; B. Sand core core extension section; C. Pressure holding air circuit. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] like Figures 1 to 8 As shown in the figure, this embodiment provides a forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors, which is arranged outside the casting mold A of the low-pressure casting equipment. The casting mold A can be a metal mold, a metal mold and sand core combination mold, or other mold structures suitable for low-pressure casting of GIS aluminum alloy conductors. A sand core is provided inside the casting mold A, and the core bone end of the sand core forms a sand core core bone extension section B that extends out of the casting mold A. This device does not constitute the cavity structure of the casting mold A, nor does it require the addition of chills, core supports, or screws inside the casting mold A. Instead, it forms an independent mechanical reference outside the casting mold A through an external frame 1. A forming clearance channel 2 is formed in the middle of the external frame 1. The forming clearance channel 2 extends along the conductor forming axis and is used to avoid the sand core core extension section B, the positioning sleeve 20, and the external protruding area of ​​the casting mold A. The external frame 1 can be formed by combining rectangular steel pipes, thick steel plates, or cast iron bases. The bottom of the external frame 1 can be provided with foot holes or adjustable feet for leveling in the low-pressure casting station. The center height of the forming clearance channel 2 is preferably consistent with the theoretical center height of the sand core core extension section B, thereby enabling the device to have a coaxial stable reference independent of the mold.

[0032] like Figure 1 and Figure 2As shown, the external frame 1 is equipped with two or more longitudinal bearing beams 3, which are arranged parallel to the axial direction of the forming clearance channel 2. The adjustable base 4 is slidably installed on the longitudinal bearing beams 3, and the stabilizing ring seat 6 is fixed on the adjustable base 4. The locking element 5 is located between the adjustable base 4 and the longitudinal bearing beams 3. The locking element 5 can be a pressure plate bolt structure, an eccentric locking handle structure, or a wedge locking structure. When the outward extension length of the sand core of different specifications of ultra-high voltage GIS aluminum alloy conductors changes, the operator can loosen the locking element 5, allowing the adjustable base 4 to move along the longitudinal bearing beams 3, adjust the stabilizing ring seat 6 to the position corresponding to the stable position of the outward extension section B of the sand core, and then tighten the locking element 5. The stabilizing ring seat 6 is preferably a vertically arranged circular ring plate, or it can be a rectangular ring plate with a rectangular outer contour and a circular central hole. The central hole of the stabilizing ring seat 6 is coaxial with the forming clearance channel 2. The stabilizing ring seat 6 is spaced apart from the outer wall of the casting mold A to avoid the thermal deformation of the casting mold A being directly transferred to the stabilizing ring seat 6 when it expands thermally. For a short sand core core extension section B, only one stabilizing ring seat 6 can be provided; for a long or heavy sand core core extension section B, it is preferable to provide two stabilizing ring seats 6 along the longitudinal bearing beam 3. The two stabilizing ring seats 6 hold the positioning sleeve 20 at different axial positions, thereby achieving multi-point external stabilization without changing the structure of the casting mold A.

[0033] like Figures 3 to 6As shown, an annular guide cavity 7 is provided inside the stabilizing ring seat 6. The annular guide cavity 7 extends circumferentially along the stabilizing ring seat 6 and is coaxial with the forming clearance channel 2. An axial pressure ring 8 is slidably disposed in the annular guide cavity 7, and the axial pressure ring 8 can move a small stroke along the axial direction of the forming clearance channel 2. A pressure holding and pressure tapping stabilizing mechanism is provided on the stabilizing ring seat 6. The pressure holding and pressure tapping stabilizing mechanism includes a pressure tapping diaphragm cavity 9 disposed on one axial side of the stabilizing ring seat 6. The pressure tapping diaphragm cavity 9 is connected to the pressure holding gas circuit C of the low-pressure casting equipment through a pressure tapping connector 10. A throttling buffer valve 29 is provided between the pressure tapping connector 10 and the pressure holding gas circuit C. The throttling buffer valve 29 can be a valve body with a microporous throttling channel or a one-way flow limiting valve body with a buffer cavity, so that the pressure tapping diaphragm cavity 9 can sense the pressure change of the pressure holding gas circuit C, but will not instantly extract a large amount of gas due to the action of external mechanical devices. A diaphragm 11 is installed inside the pressure tapping diaphragm cavity 9, dividing the cavity into a pressure tapping side and an execution side. The pressure tapping side is connected to the pressure tapping connector 10, and the execution side corresponds to the force transmission push rod 12. The diaphragm 11 can be a metal corrugated diaphragm, a heat-resistant rubber diaphragm, or a composite diaphragm formed by combining a metal sheet and a heat-resistant flexible layer. When the pressure holding gas path C is pressurized, the pressure acts on the pressure tapping side of the diaphragm 11, causing the diaphragm 11 to deform towards the execution side and push the force transmission push rod 12. The force transmission push rod 12 then pushes the axial pressure ring 8 to move axially along the annular guide cavity 7. Since the diaphragm 11 separates the pressure tapping side and the execution side, the gas in the pressure holding gas path C will not enter the area where the axial pressure ring 8, the wedge-shaped push ring 13, and the stabilizing slider 15 are located, thereby achieving isolation between pressure sampling and mechanical execution.

[0034] like Figure 5 and Figure 6As shown, a wedge-shaped push ring 13 is fixed or integrally formed on the inner side of the axial pressure ring 8. The wedge-shaped push ring 13 is an annular conical surface coaxial with the forming clearance channel 2, and its conical surface faces the mating inclined surface 16 of the stabilizing slider 15. Several radial grooves 14 are formed on the stabilizing ring seat 6. The radial grooves 14 can be T-shaped grooves or dovetail grooves. The four radial grooves 14 are preferably set at the upper, lower, left and right positions of the stabilizing ring seat 6 and distributed at equal angles of 90° intervals. Alternatively, three or six radial grooves 14 can be set according to the diameter of the positioning sleeve 20 and the weight of the core. A stabilizing slider 15 is slidably installed in each radial groove 14. The stabilizing slider 15 is a strip slider, and its outer end forms a mating inclined surface 16. The mating inclined surface 16 is in contact with or maintains a small gap with the conical surface of the wedge-shaped push ring 13. Its inner end is connected to the arc-shaped pressure claw 18 through the stabilizing claw seat 17. When the axial pressure ring 8 moves axially under the push of the force transmission rod 12, the annular conical surface of the wedge-shaped push ring 13 simultaneously presses the mating inclined surface 16 of each stabilizing slider 15. Since each mating inclined surface 16 is arranged at equal angles around the same axis, each stabilizing slider 15 slides synchronously towards the center of the forming avoidance channel 2 along the corresponding radial groove 14. Each arc-shaped pressure claw 18 then holds the positioning sleeve 20 or the extended section B of the sand core core in a centripetal direction. The inclination angle of the mating inclined surface 16 is preferably 6° to 18°. Within this angle range, the small pressure provided by the pressure holding air circuit C can be converted into a sufficient radial stabilizing force through the effective pressure-bearing area of ​​the diaphragm 11 and the inclined surface of the wedge-shaped push ring 13. At the same time, it can reliably exit through the return spring 28 after pressure relief, thereby converting the pressure holding pressure of low-pressure casting into a radial pressure stabilizing force that automatically changes with the process stage.

[0035] like Figure 3 , Figure 4 and Figure 7As shown, the arc-shaped pressure claw 18 is tile-shaped, with a concave arc surface on the side facing the center of the forming clearance channel 2. The radius of curvature of the concave arc surface corresponds to the outer radius of the positioning sleeve 20. A heat-insulating pad 19 is installed on the concave arc surface of the arc-shaped pressure claw 18. The heat-insulating pad 19 can be detachably installed by countersunk screws, dovetail grooves, or pressure strips. The heat-insulating pad 19 is preferably a graphite pad, a ceramic fiber pad, or a heat-resistant composite pad, used to reduce heat conduction from the positioning sleeve 20 to the arc-shaped pressure claw 18 and reduce metal hard contact indentations. Both axial ends of the arc-shaped pressure claw 18 are provided with chamfered guide surfaces. When there is a slight axial misalignment between the positioning sleeve 20 and the arc-shaped pressure claw 18, the chamfered guide surfaces can guide the positioning sleeve 20 into each arc-shaped pressure claw. The holding area formed by 18 has a floating groove 24 on the stabilizing claw seat 17. The floating groove 24 extends axially along the forming avoidance channel 2. A floating block 25 is slidably disposed in the floating groove 24. The arc-shaped pressure claw 18 is fixed on the floating block 25. Disc springs 26 are respectively disposed on both sides of the floating block 25. One end of the disc spring 26 abuts against the floating block 25, and the other end abuts against the end wall or end cap of the floating groove 24. The limiting pin 27 passes through the elongated hole on the stabilizing claw seat 17 and cooperates with the floating block 25 to limit the axial floating stroke of the floating block 25. Preferably, the floating stroke of the floating block 25 on one side is 1mm to 5mm, so that the arc-shaped pressure claw 18 can maintain stable pressing in the radial direction while generating limited axial clearance with the thermal expansion and contraction of the sand core core extension section B or the positioning sleeve 20, thereby avoiding cracking of the sand core end or core pulling caused by rigid clamping.

[0036] like Figure 8 As shown, the positioning sleeve 20 is a split cylindrical sleeve, comprising a first half-sleeve 21 and a second half-sleeve 22. The first half-sleeve 21 and the second half-sleeve 22 are engaged with each other and connected by bolts, hooks, or clamps to form a complete cylinder. The inner diameter of the positioning sleeve 20 is adapted to the outer diameter of the sand core core extension section B. It can be directly fitted onto the metal core core extension section, or a thin layer of heat-resistant flexible lining can be provided on the inner surface of the hole to prevent damage to the sand core core extension section B during clamping. The outer cylindrical surface of the positioning sleeve 20 is a smooth cylindrical surface used to contact the heat-insulating pads 19 on the multiple arc-shaped pressure claws 18. An end shoulder 23 is provided at the axial end of the positioning sleeve 20. The end shoulder 23 can form a limiting fit with the axial side of the arc-shaped pressure claw 18 to prevent excessive axial movement of the positioning sleeve 20 relative to the arc-shaped pressure claw 18. The positioning sleeve 20 can be made of 45 steel, heat-resistant stainless steel or aluminum bronze. Its outer surface can be ground to improve the uniformity of force when multiple arc-shaped pressure claws 18 hold it, thereby converting the irregular or fragile sand core bone protrusion section B into a standard cylindrical reference that is easy to hold externally.

[0037] When using this device, firstly, the external frame 1 is placed outside the low-pressure casting station, so that the forming clearance channel 2 is roughly aligned with the theoretical axis of the inner conductor cavity of the casting mold A. The levelness and height of the external frame 1 are then corrected by the bottom support feet or anchor bolts of the external frame 1. Then, according to the length of the sand core core extension section B and the end position of the casting mold A, the locking piece 5 is loosened, allowing the adjustable base 4 to move along the longitudinal bearing beam 3. The stabilizing ring seat 6 is adjusted to the axial position required for the sand core core extension section B or the positioning sleeve 20 to be stable. Then, the locking piece 5 is tightened. If the outer surface of the sand core core extension section B can directly withstand the pressure, the arc-shaped pressure claw 18 can directly hold the sand core core extension section B. If the outer surface of the sand core core extension section B is easily damaged or has an irregular outer diameter, the first half-set 21 and the second half-set 22 are first fastened to the outside of the sand core core extension section B and locked to form the positioning sleeve 20, so that the outer circular surface of the positioning sleeve 20 is located in the central area of ​​the stabilizing ring seat 6. At this time, the pressure-holding air circuit C has not yet been pressurized. The reset spring 28 keeps the axial pressure ring 8 in the retracted position. The wedge-shaped push ring 13 does not apply strong thrust to the stabilizing slider 15. Each arc-shaped pressure claw 18 is in an open or light contact state, which facilitates mold closing, core loading and centering operations. This ensures that the device will not hinder the mold preparation process before casting.

[0038] When low-pressure casting begins, the pressure-holding gas path C gradually increases pressure according to the liquid rising, mold filling, pressurization and pressure holding crystallization process. The pressure is transmitted to the pressure-taking side of the pressure-taking diaphragm cavity 9 through the throttling buffer valve 29. Under the action of pressure, the diaphragm 11 deforms towards the execution side and pushes the force transmission rod 12. The force transmission rod 12 pushes the axial pressure ring 8 to move axially in the annular guide cavity 7. The axial pressure ring 8 drives the wedge-shaped push ring 13 to squeeze the mating inclined surface 16 of multiple stabilizing sliders 15. Each stabilizing slider 15 slides inward along the radial groove 14 at the same time. Multiple arc-shaped pressure claws 18 synchronously hold the positioning sleeve 20 or the sand core core extension section B in a centripetal manner. As the pressure in the holding gas path C increases, the pressure acting on the diaphragm 11 increases, and the axial force output by the force transmission rod 12 and the axial pressure ring 8 increases accordingly. The radial stabilizing force converted by the wedge-shaped push ring 13 also increases. Therefore, the extended section B of the sand core skeleton obtains stronger radial stability support during the stage when the buoyancy of the aluminum liquid and the filling impact are more obvious, and will not continuously bear excessive clamping force before pressurization or after depressurization. Taking an embodiment without limiting the protection range as an example, the effective pressure-bearing area of ​​the pressure tapping diaphragm cavity 9 can be set to 80cm² to 500cm², and the inclination angle of the inclined plane 16 can be set to 6° to 18°. Within the commonly used holding pressure range of low-pressure casting, the radial stabilizing load required to stabilize the extended section B of the sand core skeleton can be obtained, thereby making the stabilizing action of the device correspond to the low-pressure casting process pressure.

[0039] As a non-limiting process verification embodiment, a GIS aluminum alloy conductor with a length of 2400 mm and an inner diameter of 180 mm was used. The sand core core extension length was 420 mm, the positioning sleeve 20 had an outer diameter of 95 mm, the stabilizing ring seat 6 used four equally angled stabilizing sliders 15 and arc-shaped pressure claws 18, the effective pressure-bearing area of ​​the pressure tapping diaphragm cavity 9 was 180 cm², the inclination angle of the mating inclined surface 16 was 10°, the pressure holding pressure of the pressure holding air circuit C was 0.08 MPa to 0.18 MPa, and the equivalent throttling orifice diameter of the throttling buffer valve 29 was 0.8 mm to 1.2 mm. A comparison was made between the use of this device and the use of this device using the same mold and the same low-pressure casting curve. The obtained parameters and evaluation results are shown in Table 1 below.

[0040] Table 1. Parameters and Comparison Results of Examples GIS aluminum alloy conductor length / inner diameter 2400mm / 180mm 2400mm / 180mm Same casting specifications Sand core core extension length 420mm 420mm Same core loading conditions Pressure holding range 0.08MPa to 0.18MPa 0.08MPa to 0.18MPa Same low-pressure casting curve Diaphragm effective area / wedge angle / number of sliders Not set 180cm² / 10° / 4 pieces Corresponding to four-claw synchronous centripetal pressure Maximum radial compressive force of a single arc-shaped pressure claw No active radial stabilizing force was formed. 1.5kN to 3.0kN Calculated based on pressure holding pressure and wedge force transmission. Coaxiality deviation of casting inner hole 0.80mm to 0.90mm 0.28mm to 0.35mm Statistics based on the detection points at both ends and the middle of the conductor Maximum deviation of local wall thickness 1.4mm to 1.7mm 0.5mm to 0.7mm The main reason is the improvement of the coaxiality of the internal cavity. Peak pressure fluctuation in the pressure-holding air circuit ±0.010MPa Within ±0.012MPa The throttling buffer valve limits the instantaneous air intake, and the pressure curve shows no significant abrupt change. Single batch return or scrap ratio Approximately 10% to 12% Approximately 2% to 4% The main purpose is to reduce insufficient machining allowance in subsequent processes caused by inner hole eccentricity.

[0041] As can be seen from the above embodiments, this device does not simply connect a common self-centering clamp to the core, but uses the original pressure-holding air circuit C of low-pressure casting as the source of pressure signal and driving force. The pressure-holding air circuit C is isolated from the mechanical execution area where the axial pressure ring 8, wedge-shaped push ring 13, and stabilizing slider 15 are located by the diaphragm 11. With the help of the throttling buffer valve 29, the instantaneous air intake is limited, so that the pressure holding curve is basically unaffected by the external mechanism. The coaxial wedge-shaped push ring 13 simultaneously drives multiple equidistantly distributed stabilizing sliders 15, so that multiple arc-shaped pressure claws 18 form synchronous centripetal pressure around the positioning sleeve 20. The arc-shaped pressure claws 18 then form axial clearance through the floating block 25 and the disc spring 26. The positioning sleeve 20 converts the irregular or easily damaged sand core protrusion section B into a standard cylindrical holding reference. The aforementioned pressure sampling, isolation force transmission, buffer gas sampling, synchronous radial pressure holding, and axial clearance work together to improve the radial stability of the core during the pressure holding stage, while reducing the risk of contaminating the pressure holding gas path, damaging the core, or restricting thermal expansion.

[0042] During the pressure holding and crystallization stage, if the extended section B of the sand core is subjected to the buoyancy of the molten aluminum or the thermal expansion of the sand core, causing it to float upwards or radially shift, this shifting tendency will be transmitted through the positioning sleeve 20 to the arc-shaped pressure claw 18, the stabilizing claw seat 17, the stabilizing slider 15, the stabilizing ring seat 6, and the external frame 1. The external frame 1 will bear the external force, keeping the extended section B of the sand core near the center of the forming avoidance channel 2. Since the wedge-shaped push ring 13 is a coaxial annular conical surface part, and each radial groove 14 is distributed at equal angles with the axis of the forming avoidance channel 2 as the center, the holding force of each arc-shaped pressure claw 18 forms an approximately balanced centripetal constraint around the positioning sleeve 20, which will not push the core in the opposite direction as a single-sided pressure plate or ordinary bolt tightening would. If the extended section B of the sand core or the positioning sleeve 20 undergoes slight thermal expansion and contraction along the axial direction of the forming avoidance channel 2, the arc-shaped pressure claw 18 can move with the floating block 25 in the floating groove 24 and absorb the axial displacement through the disc springs 26 on both sides. The limiting pin 27 prevents the floating block 25 from overtraveling and coming off, thus forming a composite stable state of "radial compression and axial clearance".

[0043] After the casting solidifies and enters the depressurization stage, the pressure in the holding gas circuit C decreases, the pushing force of the diaphragm 11 on the force transmission rod 12 decreases or disappears, the return spring 28 drives the axial pressure ring 8 to retract, the wedge-shaped push ring 13 releases the pressure on the mating inclined surface 16, the stabilizing slider 15 returns to its original position along the radial groove 14, and the arc-shaped pressure claw 18 moves away from the positioning sleeve 20 or the extended section B of the sand core. If the diaphragm 11 does not return sufficiently due to high-temperature dust, aluminum molten splashing, or local thermal expansion, the operator can pull the depressurization handle 30 to connect the pressure tapping side of the pressure tapping diaphragm cavity 9 with the outside, quickly releasing the residual pressure on the pressure tapping side and ensuring that the force transmission rod 12, the axial pressure ring 8, and the wedge-shaped push ring 13 return to their initial positions. After the arc-shaped pressure claw 18 is fully opened, the positioning sleeve 20 can be removed, or the mold opening, core removal, and part removal operations can be performed while the positioning sleeve 20 is still fitted on the extended section B of the sand core, thus completing one forming stabilization process.

[0044] In a preferred embodiment, two stabilizing ring seats 6 are provided on the longitudinal bearing beam 3. The two stabilizing ring seats 6 are located at the near-mold end and the far-mold end of the sand core core extension section B, respectively. Each stabilizing ring seat 6 includes a pressure tapping diaphragm cavity 9, an axial pressure ring 8, a wedge-shaped push ring 13, a stabilizing slider 15, and an arc-shaped pressure claw 18. The pressure tapping connector 10 of each stabilizing ring seat 6 is connected to the pressure holding gas circuit C through the same pressure tapping pipeline. When the pressure holding gas circuit C is pressurized, the arc-shaped pressure claws 18 of the two stabilizing ring seats 6 synchronously press the stabilizing sleeve 20 or different axial positions of the sand core core extension section B in a centripetal direction; when the pressure holding gas circuit C is depressurized, the two stabilizing ring seats 6 are released synchronously. This double-ring structure is suitable for long-length ultra-high voltage GIS aluminum alloy conductor sand core core extension sections B, which can further reduce the possibility of the core bending or end swinging during the pressure holding stage, while still keeping the device independent of the casting mold A, without needing to change the cavity, gating, chills, or venting structure of the casting mold A.

[0045] In another alternative embodiment, the stabilizing ring seat 6 is provided with three, four, or six radial grooves 14 and a corresponding number of stabilizing sliders 15 and arc-shaped pressure claws 18. For positioning sleeves 20 with smaller outer diameters and lighter core weights, three arc-shaped pressure claws 18 can be distributed at 120° intervals; for products with larger outer diameters, heavier core weights, or higher requirements for conductor inner cavity coaxiality, four or six arc-shaped pressure claws 18 are preferred to increase the circumferential contact area and reduce the local contact stress of a single arc-shaped pressure claw 18. The arc-shaped pressure claws 18 can be made into different specifications according to the outer diameter of the positioning sleeve 20 and can be detachably connected to the floating block 25 by bolts. The heat insulation pad 19 can also be replaced periodically according to the casting temperature and wear condition, thereby improving the versatility of this device on multi-specification GIS aluminum alloy conductor production lines.

[0046] The dimensional parameters in this embodiment are only used to illustrate one possible implementation of the present invention and do not constitute a limitation on the scope of protection. For example, the outer diameter of the stabilizing ring seat 6 can be 300mm to 1200mm, the diameter of the central hole can be 100mm to 600mm, the radial stroke of the stabilizing slider 15 can be 10mm to 80mm, the outer diameter of the positioning sleeve 20 can be 50mm to 300mm, the effective pressure-bearing area of ​​the pressure-taking diaphragm cavity 9 can be adjusted according to the pressure holding pressure of the low-pressure casting equipment and the weight of the sand core core extension section B, and the inclination angle of the inclined plane 16 can be selected according to the required radial pressure stabilizing force and reset reliability. As long as the stabilizing ring seat 6 is placed externally on the casting mold A, the pressure of the pressure holding air passage C is obtained through the diaphragm plate 11 and the axial pressure ring 8 is driven, and then the axial force is converted into the radial centripetal pressure stabilizing force of multiple arc-shaped pressure claws 18 through the wedge-shaped push ring 13, it should be understood that it falls within the technical concept scope of the present invention.

[0047] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0048] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors, used in conjunction with a low-pressure casting equipment including a casting mold (A) and a pressure-holding gas circuit (C), wherein the sand core within the casting mold (A) includes an extended section (B) of the sand core core extending out of the casting mold (A), characterized in that, include: An external frame (1) is installed outside the casting mold (A). The external frame (1) forms a forming clearance channel (2) extending along the conductor forming axis. A stabilizing ring seat (6) is provided on the axial position of the forming clearance channel (2) and is coaxial with it and spaced from the outer wall of the casting mold (A). The stabilizing ring seat (6) is provided with a pressure holding and pressure tapping stabilizing mechanism. The pressure holding and pressure tapping stabilizing mechanism includes a pressure tapping diaphragm cavity (9), an axial pressure ring (8), a wedge-shaped push ring (13), and several stabilizing sliders (15) distributed circumferentially. The pressure tapping diaphragm cavity (9) contains a pressure tapping diaphragm cavity (9). The diaphragm (11) divides it into a pressure-taking side and an execution side. The pressure-taking side is connected to the pressure-holding air passage (C) through a pressure-taking connector (10). The execution side pushes the axial pressure ring (8) to move axially through a force-transmitting push rod (12). The wedge-shaped push ring (13) moves with the axial pressure ring (8) and cooperates with the mating inclined surface (16) of each of the stabilizing sliders (15) to push each of the stabilizing sliders (15) to move synchronously towards the center. Then, the arc-shaped pressure claw (18) presses and stabilizes the sand core core extension section (B) or the positioning sleeve (20) sleeved on its outside. The pressure holding and pressure tapping mechanism includes a pressure tapping diaphragm cavity (9) disposed on one axial side of the stabilizing ring seat (6). The pressure tapping end of the pressure tapping diaphragm cavity (9) is provided with a pressure tapping connector (10), which is used to communicate with the pressure holding gas path (C). A diaphragm sheet (11) is disposed inside the pressure tapping diaphragm cavity (9), which divides the pressure tapping diaphragm cavity (9) into a pressure tapping side close to the pressure tapping connector (10) and an execution side away from the pressure tapping connector (10). An annular guide cavity (7) is provided inside the stabilizing ring seat (6), and an axial pressure ring (8) is slidably provided inside the annular guide cavity (7); a force transmission rod (12) is provided on the execution side of the pressure tapping diaphragm cavity (9), the force transmission rod (12) abuts against the axial pressure ring (8), and a wedge-shaped push ring (13) is provided on the inner side of the axial pressure ring (8); a reset spring (28) is sleeved on the outer side of the force transmission rod (12), one end of the reset spring (28) abuts against the pressure tapping diaphragm cavity (9) or the stabilizing ring seat (6), and the other end abuts against the axial pressure ring (8) or a spring stop connected to the force transmission rod (12), for driving the axial pressure ring (8) to reset after the pressure tapping diaphragm cavity (9) is depressurized; The stabilizing ring seat (6) is provided with a plurality of radial grooves (14) along the radial direction. A stabilizing slider (15) is slidably disposed in the radial grooves (14). The end of the stabilizing slider (15) facing the wedge-shaped push ring (13) is formed with a mating inclined surface (16). The end of the stabilizing slider (15) facing the center of the forming avoidance channel (2) is connected to an arc-shaped pressure claw (18) through a stabilizing claw seat (17). The wedge-shaped push ring (13) and the mating inclined surface (16) cooperate to push the stabilizing slider (15) toward the center of the forming avoidance channel (2) when the axial pressure ring (8) moves axially.

2. The forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors according to claim 1, characterized in that, The external frame (1) is provided with a longitudinal bearing beam (3) parallel to the forming avoidance channel (2). An adjustable base (4) is slidably provided on the longitudinal bearing beam (3). The stabilizing ring seat (6) is fixed on the adjustable base (4). A locking member (5) is provided between the adjustable base (4) and the longitudinal bearing beam (3). The locking member (5) is used to fix the adjustable base (4) on the longitudinal bearing beam (3) after the stabilizing ring seat (6) is adjusted to a predetermined position along the conductor forming axis.

3. The forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors according to claim 1, characterized in that, A throttling buffer valve (29) is provided between the pressure tapping connector (10) and the pressure holding gas passage (C). The throttling buffer valve (29) is used to limit the instantaneous gas flow between the pressure holding gas passage (C) and the pressure tapping side of the pressure tapping diaphragm chamber (9). A pressure relief handle (30) is provided on the throttling buffer valve (29). The pressure relief handle (30) is used to connect the pressure tapping side of the pressure tapping diaphragm chamber (9) with the outside.

4. The forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors according to claim 1, characterized in that, Several radial grooves (14) are distributed at equal angles around the axis of the forming clearance channel (2). The radial grooves (14) are T-shaped grooves or dovetail grooves. The stabilizing slider (15) is a strip slider that is adapted to the T-shaped groove or dovetail groove. The inclination angle of the mating inclined surface (16) is 6° to 18°.

5. The forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors according to claim 1, characterized in that, The arc-shaped pressure claw (18) is tile-shaped. The arc-shaped pressure claw (18) forms a concave arc surface on one side facing the center of the forming avoidance channel (2). A heat insulation pad (19) is detachably provided on the concave arc surface. The heat insulation pad (19) is a graphite pad, a ceramic fiber pad, or a heat-resistant composite pad. Both ends of the arc-shaped pressure claw (18) form chamfered guide surfaces.

6. The forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors according to claim 5, characterized in that, The stabilizing claw seat (17) is provided with a floating groove (24) extending axially along the forming clearance channel (2). A floating block (25) is slidably disposed in the floating groove (24). The arc-shaped pressure claw (18) is fixed on the floating block (25). Disc springs (26) abut against the axial sides of the floating block (25). A limit pin (27) is provided on the stabilizing claw seat (17). The limit pin (27) is used to limit the axial floating stroke of the floating block (25) in the floating groove (24).

7. The forming and stabilizing device for ultra-high voltage GIS aluminum alloy conductors according to claim 1, characterized in that, The positioning sleeve (20) is a split cylindrical sleeve that is fitted on the outside of the extended section (B) of the sand core bone. The positioning sleeve (20) includes a first half sleeve (21) and a second half sleeve (22) that are interlocked with each other. The first half sleeve (21) and the second half sleeve (22) are connected by fasteners. The axial end of the positioning sleeve (20) is provided with an end shoulder (23) that is axially limited and cooperates with the arc-shaped pressure claw (18).

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