High-temperature superconducting magnetic levitation landing gear mounting seat and 3D printing resin sand casting mold and casting method thereof

Abstract

This invention provides a high-temperature superconducting magnetic levitation landing gear mounting base and its 3D-printed resin sand mold and casting method, relating to the field of casting technology. Based on the 3D-printed resin sand mold, the preset gating structure, and the designed parting surface, the base is divided into a lower sand mold, a middle sand mold, an upper sand mold, and a sand core. During mold assembly, the lower sand mold, the middle sand mold, the sand core, and the upper sand mold are placed in sequence for casting the high-temperature superconducting magnetic levitation landing gear mounting base. The operation is simple and convenient. During casting, the molten aluminum alloy enters the sprue under air pressure, then splits into two horizontal gating channels, which are connected to each other. The filling process then proceeds through multiple ingates. The flow rate of the molten aluminum is slow, reducing the generation of air entrapment and oxide inclusions. The filling process is short, and the temperature loss of the molten aluminum is small.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, specifically relating to a high-temperature superconducting magnetic levitation landing gear mounting base and its 3D printed resin sand casting mold and casting method. Background Technology

[0002] A high-temperature superconducting maglev train with a speed of 600 km / h relies on landing gear for support at low speeds, while at high speeds it relies entirely on superconducting magnets for contactless levitation. As a key actuator for the retraction and extension of the running wheels, the installation accuracy and stiffness of the landing gear directly determine the stability of wheel-rail contact, thus affecting the safety of train start-up, emergency braking, and chutes protection. Current technologies generally place the landing gear on the suspension frame, connected to the superconducting magnet frame via a primary suspension system. This approach has the following drawbacks: 1. The dynamic deflection of the primary suspension springs is superimposed on the landing gear stroke, forcing the landing gear to be larger to compensate for displacement losses, which is detrimental to lightweighting and compactness; 2. Under high-speed conditions, the elastic deformation of the frame can easily cause slight angular displacement at the landing gear mounting points, leading to drift in the running wheel positioning parameters and reducing the reliability of wheel-rail contact. Therefore, there is an urgent need for a high-temperature superconducting magnetic levitation landing gear mounting base that can be directly and rigidly connected to a superconducting magnet and is not affected by the deformation of the primary suspension system, in order to meet the urgent needs of 600km / h class high-speed trains for lightweight, high rigidity and high reliability. Summary of the Invention

[0003] In view of this, the present invention provides a high-temperature superconducting magnetic levitation landing gear mounting base that can be directly and rigidly connected to a superconducting magnet and is not affected by the deformation of the primary suspension system, so as to meet the urgent needs of 600 km / h class high-speed trains for lightweight, high rigidity and high reliability.

[0004] It is also necessary to provide a 3D printed resin sand casting mold for a high-temperature superconducting magnetic levitation landing gear mounting base.

[0005] It is also necessary to provide a casting method for a high-temperature superconducting magnetic levitation landing gear mounting base.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A high-temperature superconducting magnetic levitation landing gear mounting base includes a first connecting base and a second connecting base symmetrically arranged. The first connecting base has the same structure as the second connecting base. Both the first and second connecting bases are cast from molten aluminum. The cross-section of the first connecting base is f-shaped. The first connecting base includes a first connecting member, a middle transition portion, and a second connecting member, which are integrally formed sequentially. The cross-section of the first connecting member is half-C-shaped. A first groove is provided on the side of one end of the first connecting member, and a first cavity is provided on the other end of the first connecting member. The opening direction of the first groove is opposite to that of the second connecting base. A first connecting hole is provided at the top and bottom of the first groove, and the two first connecting holes are coaxial. A second groove is provided on the side of the free end of the second connecting member. The opening direction of the second groove is opposite to that of the second connecting base, and a second connecting hole is provided at the top and bottom of the second groove.

[0008] Preferably, the middle transition portion includes a first transition member, a transverse transition member, and a second transition member connected in sequence. The first transition member has a second cavity, and a first through hole is provided at the bottom of the first cavity. The first connector has a first protrusion at the top, and the first through hole and the first protrusion are coaxial. The first cavity and the second cavity are connected by a connecting hole. The second transition member has a third cavity, and a second through hole is provided at the bottom of the third cavity. The second transition member has a second protrusion at the top, and the second through hole and the second protrusion are coaxial. The thickness of the transverse transition member is greater than the thickness of the first connector and less than the thickness of the second connector. The top surface of the first transition member is an arc surface to connect the first connector and the transverse transition member through the first transition member. The top and bottom surfaces of the second transition member are both arc surfaces to connect the second connector and the transverse transition member through the second transition member.

[0009] A 3D printed resin sand mold includes a lower sand mold, a middle sand mold, and an upper sand mold inserted sequentially from bottom to top, and a sand core embedded between the middle sand mold and the upper sand mold. The lower sand mold is provided with a sprue, and the parting surface of the lower sand mold is provided with two cross-shaped horizontal runners that are connected. The sprue is connected to the two horizontal runners at the position where they are connected. The middle sand mold is provided with several ingates along the thickness direction. The middle sand mold is provided with two first casting cavities with the same shape as the bottom and side surfaces of the first and second connecting seats. The bottom of the upper sand mold is provided with two second casting cavities with the same shape as the bottom and side surfaces of the first and second connecting seats. The ingates are connected to the first casting cavities. The sand core is located in the first casting cavity, and the bottom of the sand core is inserted into the first casting cavity, and the top of the sand core is inserted into the second casting cavity.

[0010] Preferably, the sand core portion consists of two sets, which are symmetrically arranged in different first casting cavities. Each sand core portion includes sand core No. 1, sand core No. 2, sand core No. 3, sand core No. 4, and sand core No. 5 arranged sequentially along the length of the first casting cavity. Sand core No. 2 and sand core No. 3 are connected by connecting columns. Sand core No. 2, sand core No. 3, and sand core No. 4 have the same structure as the first cavity, the second cavity, and the third cavity. Sand core No. 1 and sand core No. 2 constitute the casting structure of the first connecting member. The gap between sand core No. 5 and sand core No. 5 and sand core No. 4 constitutes the structure of the second connecting member.

[0011] Preferably, positioning core heads are provided at the top and bottom of sand cores No. 2 and No. 4, and elliptical core head holes are provided at the bottom of sand cores No. 3 and No. 4. Positioning holes and elliptical positioning posts are provided corresponding to the first casting cavity. The sand core is positioned by matching the positioning core head with the positioning hole and inserting the elliptical core head hole with the elliptical positioning post.

[0012] Preferably, the first casting cavity is provided with a plurality of first chill holes.

[0013] Preferably, the second casting cavity is provided with a sprue blind hole and a plurality of second chill holes, and the upper sand mold is also provided with a plurality of vent holes.

[0014] Preferably, the elliptical positioning post is provided with a draft angle.

[0015] A casting method for casting a high-temperature superconducting magnetic levitation landing gear mounting base using a 3D-printed resin sand mold as described above includes the following steps:

[0016] S1: A mold consisting of a lower sand mold, a middle sand mold, an upper sand mold, and a sand core.

[0017] S2: The aluminum liquid is injected into the mounting cavity formed by the first casting cavity, the sand mold section, and the second casting cavity through the straight sprue, horizontal sprue, and inner sprue of the lower sand mold to fill the mold;

[0018] S3: After the filling is completed, increase the pressure on the basis of the filling pressure and hold the pressure to achieve automatic feeding of the casting when the aluminum liquid changes from liquid to solid.

[0019] S4: After the feeding is completed, the pressure is released, the casting is completed, and the welding is performed to obtain the high-temperature superconducting magnetic levitation landing gear mounting base casting.

[0020] Preferably, the temperature of the molten aluminum is 715℃-725℃, and the increased pressure is 50mbar-70mbar.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The high-temperature superconducting magnetic levitation landing gear mounting base provided by this invention is cast from molten aluminum, allowing for rapid cooling of the casting through a metal mold. This results in fine grains and good mechanical properties, meeting the requirements of high-temperature superconducting magnetic levitation trains operating at speeds of 600 km / h. Simultaneously, the cast mounting base is rigidly connected directly to the landing gear. The first connecting piece, the first transition piece, and the second transition piece are equipped with a first cavity, a second cavity, and a third cavity, respectively, to reduce the weight of the mounting base and meet the urgent requirements of 600 km / h high-speed trains for lightweight, high rigidity, and high reliability.

[0023] This invention also provides a 3D printed resin sand casting mold. By setting up a lower sand mold, a middle sand mold, and an upper sand mold inserted from bottom to top, and pre-setting a sprue, a runner, and a suitable ingate on the lower sand mold to automatically compensate for thermal shrinkage without affecting the application of a coating to prevent direct contact between molten aluminum and the sand mold, thus avoiding sand adhesion defects, the middle and upper sand molds are then equipped with a first casting cavity and a second casting cavity identical in shape to the mounting base. A sand core is also provided within the middle sand mold to accommodate the cavities within the first and second connecting bases. The mold assembly process is simple and convenient, reducing time costs. It satisfies the requirements for the preparation of a lightweight, high-rigidity, and highly reliable mounting base. Simultaneously, the gating system composed of the sprue, runner, and ingate significantly reduces shrinkage porosity, shrinkage holes, and oxide slag defects in the product, increasing the casting qualification rate to over 90%.

[0024] This invention also provides a casting method for a high-temperature superconducting magnetic levitation landing gear mounting base. Based on a 3D-printed resin sand mold, a pre-designed gating structure, and a designed parting surface, the method divides the mold into a lower sand mold, a middle sand mold, an upper sand mold, and a sand core. During mold assembly, the lower sand mold, middle sand mold, sand core, and upper sand mold are placed sequentially for casting the high-temperature superconducting magnetic levitation landing gear mounting base. The operation is simple and convenient. During casting, the molten aluminum alloy enters the sprue under air pressure, then branches into two horizontal runners, which are connected to each other. The filling then proceeds through multiple ingates, resulting in a smooth aluminum flow rate, reducing air entrapment and oxide inclusions. The filling process is short, and the aluminum temperature loss is minimal. When the molten aluminum rises to the cavity inside the sand core, the gas in the cavity enters the atmosphere through the holes in the upper sand mold, preventing it from remaining in the cavity and entering the molten aluminum, thus avoiding porosity defects in the casting. After the mold is filled, the aluminum liquid gradually solidifies. Due to the presence of heat spots and the slow cooling rate, as well as the shrinkage characteristics of the aluminum alloy liquid, shrinkage porosity or shrinkage cavity defects may occur in the casting. By adjusting the solidification sequence of the aluminum alloy liquid through the chills in the first and second chill holes in the middle sand mold, upper sand mold, and sand core, shrinkage porosity or shrinkage cavity defects can be avoided. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the front structure of the mounting base for a high-temperature superconducting magnetic levitation landing gear.

[0026] Figure 2 This is a schematic diagram of the back structure of the first connector.

[0027] Figure 3 This is a schematic diagram of the structure of the first connecting seat.

[0028] Figure 4 A schematic diagram of the 3D-printed resin sand casting mold for the mounting base of a high-temperature superconducting magnetic levitation landing gear.

[0029] Figure 5 This is a bottom view of the lower sand mold.

[0030] Figure 6 This is a schematic diagram of the lower sand mold structure.

[0031] Figure 7 This is a cross-sectional view of the lower sand mold.

[0032] Figure 8 This is a schematic diagram of the assembly structure of the medium sand mold and the sand core.

[0033] Figure 9 This is a schematic diagram of the medium sand mold structure.

[0034] Figure 10 This is a schematic diagram of the bottom structure of a medium sand mold.

[0035] Figure 11 This is a schematic diagram of the sand core structure.

[0036] Figure 12 This is a schematic diagram of the bottom structure of the sand core.

[0037] Figure 13 This is a schematic diagram of the assembly structure of the upper sand mold and the sand core.

[0038] Figure 14 This is a schematic diagram of the upper sand mold structure.

[0039] Figure 15 This is a schematic diagram of the casting structure of the first connecting seat.

[0040] In the figure: High-temperature superconducting magnetic levitation landing gear mounting base 10, first connecting base 100, first connecting piece 110, first groove 111, first cavity 112, first connecting hole 113, first protrusion 114, middle transition part 120, first transition piece 121, second cavity 1211, first through hole 1212, lateral transition piece 122, partition piece 1221, second transition piece 123, third cavity 1231, second through hole 1232, second protrusion 1233, elliptical weld joint 124, second connecting piece 130, second groove 131, second connecting hole 132, second connecting base 200.

[0041] 3D printed resin sand casting mold 20, lower sand mold 300, sprue 310, annular hole 311, horizontal sprue 320, branch sprue 330, positioning pin 340, sand collecting ring 350, middle sand mold 400, inner sprue 410, first casting cavity 420, positioning hole 421, elliptical positioning post 422, first chill hole 423, insertion hole 430, upper sand mold 500, second casting cavity 510, second chill hole 511, sprue blind hole 512, vent hole 520, sand core section 600, No. 1 sand core 610, No. 2 sand core 620, positioning core head 621, No. 3 sand core 630, elliptical core head hole 631, No. 4 sand core 640, No. 5 sand core 650, hoisting device 700. Detailed Implementation

[0042] The technical solutions and effects of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] Please refer to Figures 1 to 3 A high-temperature superconducting magnetic levitation landing gear mounting base 10 includes a first connecting base 100 and a second connecting base 200 symmetrically arranged. The structure of the first connecting base 100 is the same as that of the second connecting base 200. Both the first connecting base 100 and the second connecting base 200 are cast from molten aluminum. The cross-section of the first connecting base 100 is f-shaped. The first connecting base 100 includes a first connecting member 110, a middle transition portion 120, and a second connecting member 130 integrally formed sequentially. The cross-section of the first connecting member 110 is semi-C-shaped. A first groove 111 is provided on the side of one end of the connector 110, and a first cavity 112 is provided on the other end of the first connector 110. The opening direction of the first groove 111 is opposite to that of the second connecting seat 200. A first connecting hole 113 is provided at the top and bottom of the first groove 111, and the two first connecting holes 113 are coaxial. A second groove 131 is provided on the side of the free end of the second connector 130. The opening direction of the second groove 131 is opposite to that of the second connecting seat 200, and a second connecting hole 132 is provided at the top and bottom of the second groove 131.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] The high-temperature superconducting magnetic levitation landing gear mounting base 10 provided by this invention is cast from molten aluminum, which allows for rapid cooling of the casting through a metal mold, resulting in fine grains and good mechanical properties, meeting the requirements of the operation of a high-temperature superconducting magnetic levitation train with a speed of 600 km / h. At the same time, the cast mounting base 10 is directly rigidly connected to the landing gear. The first connecting member 110, the first transition member 121, and the second transition member 123 are provided with a first cavity 112, a second cavity 1211, and a third cavity 1231 to reduce the weight of the mounting base 10, so as to meet the urgent requirements of 600 km / h high-speed trains for lightweight, high rigidity, and high reliability.

[0046] Furthermore, the middle transition portion 120 includes a first transition member 121, a transverse transition member 122, and a second transition member 123 connected in sequence. The first transition member 121 has a second cavity 1211. The bottom of the first cavity 1211 has a first through hole 1212. The top of the first connector 110 has a first protrusion 114. The first through hole 1212 and the first protrusion 114 are coaxial. The first cavity 112 and the second cavity 1211 are connected by a connecting hole. The second transition member 123 has a third cavity 1231. The bottom of the third cavity 1231 has a second through hole 1232. The top of the second transition member 123 has a second protrusion 1233. 232 is coaxial with the second protrusion 1233. The thickness of the transverse transition piece 122 is greater than the thickness of the first connector 110 and less than the thickness of the second connector 130. The top surface of the first transition piece 121 is an arc surface, so as to connect the first connector 110 and the transverse transition piece 122 through the first transition piece 121. The top and bottom surfaces of the second transition piece 123 are both arc surfaces, so as to connect the second connector 130 and the transverse transition piece 122 through the second transition piece 123. A circular groove is provided on the straight segment connecting the transverse transition piece 122 with the first connector 110 and the second connector 130. Two elliptical welding ports are symmetrically provided at both ends of the circular groove for welding elliptical welded parts.

[0047] Furthermore, the top of the transverse transition member 122 is provided with two elongated grooves that are perpendicular to each other, and the bottom of the transverse transition member 122 is provided with two protrusions on the side away from the second connecting seat 200. The two protrusions are separated by a partition member 1221. The front end of the partition member 1221 is provided with two circular grooves along the height direction. The bottom end of the second connecting member 130 is provided with a groove with a triangular longitudinal section, and two protrusions are provided in the groove.

[0048] Please refer to Figures 4 to 14A 3D-printed resin sand mold 20 is used for casting the high-temperature superconducting magnetic levitation landing gear mounting base 10 as described above. It includes a lower sand mold 300, a middle sand mold 400, and an upper sand mold 500 inserted sequentially from bottom to top, and a sand core portion 600 embedded between the middle sand mold 400 and the upper sand mold 500. The lower sand mold 300 is provided with a sprue 310, and the parting surface of the lower sand mold 300 has two cross-shaped horizontal runners 320 connected to each other. The sprue 310 is connected to the position where the two horizontal runners 320 connect. The middle sand mold 400 has several ingates 410 along its thickness direction. The middle sand mold 400 is provided with two first casting cavities 420 having the same shape as the bottom and side surfaces of the first connecting seat 100 and the second connecting seat 200. The bottom of the upper sand mold 500 is provided with two second casting cavities 510 having the same shape as the bottom and side surfaces of the first connecting seat 100 and the second connecting seat 200. The inner gating 410 communicates with the first casting cavities 420. The sand core 600 is located inside the first casting cavity 420. The bottom of the sand core 600 is inserted into the first casting cavity 420, and the top of the sand core 600 is inserted into the second casting cavity 510.

[0049] By setting up a lower sand mold 300, a middle sand mold 400, and an upper sand mold 500 that are inserted from bottom to top, and pre-setting a sprue 310, a gating 320, and a suitable ingate 410 on the lower sand mold 300, automatic shrinkage compensation is achieved for hot spots without affecting the application of a coating to prevent direct contact between molten aluminum and the sand mold, thus preventing sand adhesion defects. Then, a first casting cavity 420 and a second casting cavity 510 with the same shape as the mounting base 10 are set in the middle sand mold 400 and the upper sand mold 500, respectively. A sand core 600 is set inside the middle sand mold 400 to meet the requirements of the first connecting base 1. The cavity design within the second connecting seat 200 simplifies and facilitates operation during the mold assembly process, reducing time costs. It also enables the fabrication of a lightweight, high-rigidity, and highly reliable mounting seat 10, allowing for rapid cooling of the casting through a metal mold, resulting in fine grains and excellent mechanical properties, meeting the requirements of high-temperature superconducting maglev trains operating at speeds of 600 km / h. Furthermore, the gating system, composed of a sprue 310, a runner 320, and an ingate 410, significantly reduces shrinkage porosity, shrinkage cavities, and oxide slag defects, increasing the casting qualification rate to over 90%.

[0050] Furthermore, two branch runners 330 are symmetrically arranged at the front ends of the two cross-shaped horizontal runners 320 to communicate with several ingate runners 410 and supply liquid into the first casting cavity 420. There are 14 ingate runners 410, symmetrically arranged on the two cross-shaped horizontal runners 320. Taking the first connecting seat 100 as an example: in the first casting cavity 420, the cavity portion with the same shape as the first connecting member 110 is provided with two ingate runners 410, and the cavity portion with the same shape as the first transition member 121 is provided with one ingate runner 410. Three ingates 410 are provided in the cavity portion of the transverse transition piece 122 with the same shape, and one ingate 410 is provided in the cavity portion of the second connector 130 with the same shape, so as to realize the arrangement of ingates 410 at multiple points, so that the aluminum liquid rises into the cavity smoothly, reducing the risk of aluminum liquid overturning and entrapment, greatly reducing oxide slag defects, and increasing the casting qualification rate to over 90%. At the same time, through the above-mentioned ingate 410, the aluminum liquid in the ingate 410 can be used to replenish the hot spots in different parts after the filling is completed, avoiding the generation of shrinkage porosity defects.

[0051] Furthermore, the inlet of the direct sprue 310 is provided with an annular hole 311 to be compatible with the filter device. The filter device is a ceramic filter used to filter impurities in the molten aluminum.

[0052] Furthermore, the lower sand mold 300, the middle sand mold 400, and the upper sand mold 500 are all rectangular, and each end of the lower sand mold 300, the middle sand mold 400, and the upper sand mold 500 is equipped with a hoisting device 700.

[0053] Furthermore, a positioning pin 340 is provided at the corner of the parting surface of the lower sand mold 300, an insertion hole 430 is provided on the lower parting surface of the middle sand mold 400, a positioning pin 340 is provided on the upper parting surface of the middle sand mold 400, and an insertion hole 430 is provided on the parting surface of the upper sand mold 500, for sequential positioning and installation. A sand collecting ring 350 is provided around the positioning pin 340 for collecting sand and preventing resin sand from entering the parting surface.

[0054] Furthermore, the first casting cavity 420 is provided with a plurality of first chill holes 423, and the second casting cavity 510 is provided with a plurality of second chill holes 511. The first chill holes 423, the second chill holes 511 are located in the same positions as the first connecting hole 113, the second connecting hole 132, the bottom protrusion of the transverse transition piece 122, and the bottom end protrusion of the second connecting piece 130 in the first casting cavity 420 and the second casting cavity 510. The first chill holes 423 and the second chill holes 511 are used to place chills to cool the aluminum liquid as early as possible for active feeding.

[0055] Furthermore, the sand core portion 600 is divided into two groups, which are symmetrically arranged in different first casting cavities 420. The sand core portion 600 includes sand core 1 610, sand core 2 620, sand core 3 630, sand core 4 640, and sand core 5 650 arranged sequentially along the length direction of the first casting cavity 420. Sand core 2 620 and sand core 3 630 are connected by connecting columns. Sand core 2 620, sand core 3 630, and sand core 4 640 have the same structure as the first cavity 112, the second cavity 1211, and the third cavity 1231. Sand core 1 610 and sand core 2 620 constitute the casting structure of the first connecting member 110. The gap between sand core 5 650 and sand core 4 640 constitutes the structure of the second connecting member 130.

[0056] Furthermore, positioning core heads 621 are provided at the top and bottom of sand cores 640 No. 2 and No. 4, and elliptical core head holes 631 are provided at the bottom of sand cores 640 No. 3 and No. 4. Positioning holes 421 are provided corresponding to the first casting cavity 420 and the second casting cavity 510. The first casting cavity 420 is also provided with elliptical positioning posts 422. The positioning core head 621 is matched with the positioning hole 421, and the elliptical core head hole 631 is inserted into the elliptical positioning post 422 to position the sand core part 600.

[0057] Furthermore, the No. 1 sand core 610, No. 2 sand core 620, No. 3 sand core 630, No. 4 sand core 640, and No. 5 sand core 650 are provided with cavities of a certain volume to reduce weight. Iron wires are placed inside the No. 1 sand core 610, No. 2 sand core 620, No. 3 sand core 630, No. 4 sand core 640, and No. 5 sand core 650, with the other end submerged in the medium sand mold 400, to prevent the sand cores from floating in the aluminum liquid during the casting process.

[0058] Furthermore, the elliptical positioning post 422 is provided with a draft angle for positioning, which facilitates subsequent welding and sand removal.

[0059] Furthermore, the second casting cavity 510 is provided with a sprue blind hole 512, and the upper sand mold 500 is also provided with a plurality of vent holes 520, which are connected to the second casting cavity 510.

[0060] Please refer to Figures 1 to 15 A casting method for casting a high-temperature superconducting magnetic levitation landing gear mounting base 10 using a 3D printed resin sand mold 20 as described above, includes the following steps:

[0061] S1: A casting mold 20 consisting of a lower sand mold 300, a middle sand mold 400, an upper sand mold 500, and a sand core 600;

[0062] S2: The aluminum liquid is injected into the cavity of the mounting seat 10 formed by the first casting cavity 420, the sand mold section and the second casting cavity 510 through the straight sprue 310, the horizontal sprue 320 and the inner sprue 410 of the lower sand mold 300 to fill the mold;

[0063] S3: After the filling is completed, increase the pressure on the basis of the filling pressure and hold the pressure to achieve automatic feeding of the casting when the aluminum liquid changes from liquid to solid.

[0064] S4: After the feeding is completed, the pressure is released, the casting is completed, and the elliptical welding joint 124 of the casting is repaired to obtain the high-temperature superconducting magnetic levitation landing gear mounting mold 20.

[0065] This invention also provides a casting method for a high-temperature superconducting magnetic levitation landing gear mounting base. Based on the 3D-printed resin sand mold 20, the pre-designed gating structure, and the designed parting surface, a lower sand mold 300, a middle sand mold 400, an upper sand mold 500, and a sand core 600 are formed. During mold assembly, the lower sand mold 300, the middle sand mold 400, the sand core 600, and the upper sand mold 500 are placed sequentially for casting the high-temperature superconducting magnetic levitation landing gear mounting base 10. The operation is simple and convenient. Furthermore, during casting, the molten aluminum alloy enters the sprue 310 under air pressure, then branches into two horizontal gating channels 320. These horizontal gating channels 320 are connected, and the mold is filled through multiple ingate channels 410. The flow rate of the molten aluminum is slow, reducing the generation of air entrapment and oxide inclusions. The filling process is short, and the temperature loss of the molten aluminum is small. When the molten aluminum rises to the cavity inside the sand core section 600, the gas in the cavity enters the atmosphere through the hole in the upper sand mold 500, preventing it from remaining in the cavity and entering the molten aluminum, thus causing porosity defects in the casting. After filling, the molten aluminum gradually solidifies. Due to the presence of heat points and the slow cooling rate, coupled with the shrinkage characteristics of the molten aluminum alloy, shrinkage porosity or shrinkage cavities can occur in the casting. By adjusting the solidification sequence of the molten aluminum alloy through the chills in the first and second chill holes in the middle sand mold 400, upper sand mold 500, and sand core section 600, shrinkage porosity or shrinkage cavities can be avoided.

[0066] Furthermore, before step S2, the assembled mold 20 needs to be placed on a flat plate, and multiple rectangular sand boxes are stacked to encircle the mold 20. Sand is poured in to solidify the mold 20 within the poured resin sand, thereby reinforcing the assembled 3D mold 20 and preventing the molten aluminum in the cavity from breaking through the 3D mold 20 under air pressure. Then, the molded resin sand mold is placed on a low-pressure press platform, and the sprue 310 with a filter device is aligned with the riser pipe to inject molten aluminum.

[0067] Furthermore, the filling process ends when the molten aluminum enters the vent hole 520.

[0068] Furthermore, the temperature of the molten aluminum is 715℃-725℃, and the increased pressure is 50mbar-70mbar.

[0069] Furthermore, after the filling is completed, first increase the pressure by 5mbar-10mbar and hold for 1-2 seconds to ensure full filling. Then, increase the pressure by another 5mbar-10mbar and hold for 1-4 seconds to increase the pressure for crust formation, causing the aluminum liquid to form a crust on the surface and separate from the sand mold. Then, increase the pressure by another 55mbar-65mbar and hold for 1100-1200 seconds to increase the pressure for crystallization and replenishment, adding aluminum liquid to the hot spot. After replenishment, maintain the pressure until the aluminum liquid solidifies.

[0070] As an example, a comparison table of aluminum molten casting time and pressure is shown in Table 1.

[0071] Table 1

[0072] S4: After the feeding is completed, the pressure is released and the casting is completed. Welding is performed at the elliptical hole position at the bottom of the casting to obtain the high-temperature superconducting magnetic levitation landing gear mounting seat 10 casting.

[0073] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A high-temperature superconducting magnetic levitation landing gear mounting base, characterized in that, The device includes a symmetrically arranged first connecting seat and a second connecting seat. The first connecting seat has the same structure as the second connecting seat. Both the first and second connecting seats are cast from molten aluminum. The first connecting seat has an f-shaped cross-section. The first connecting seat includes a first connecting member, a middle transition part, and a second connecting member, which are integrally formed sequentially. The first connecting member has a semi-C-shaped cross-section. A first groove is provided on the side of one end of the first connecting member, and a first cavity is provided on the other end of the first connecting member. The opening direction of the first groove is opposite to that of the second connecting seat. A first connecting hole is provided at the top and bottom of the first groove, and the two first connecting holes are coaxial. A second groove is provided on the side of the free end of the second connecting member. The opening direction of the second groove is opposite to that of the second connecting seat, and a second connecting hole is provided at the top and bottom of the second groove.

2. The high-temperature superconducting magnetic levitation landing gear mounting base as described in claim 1, characterized in that: The middle transition section includes a first transition member, a transverse transition member, and a second transition member connected in sequence. The first transition member has a second cavity, and a first through hole is provided at the bottom of the first cavity. The first connector has a first protrusion at the top, and the first through hole and the first protrusion are coaxial. The first cavity and the second cavity are connected by a connecting hole. The second transition member has a third cavity, and a second through hole is provided at the bottom of the third cavity. The second transition member has a second protrusion at the top, and the second through hole and the second protrusion are coaxial. The thickness of the transverse transition member is greater than the thickness of the first connector and less than the thickness of the second connector. The top surface of the first transition member is an arc surface to connect the first connector and the transverse transition member through the first transition member. The top and bottom surfaces of the second transition member are both arc surfaces to connect the second connector and the transverse transition member through the second transition member.

3. A 3D printed resin sand casting mold, characterized in that: The high-temperature superconducting magnetic levitation landing gear mounting base as described in claim 1 or 2 includes a lower sand mold, a middle sand mold, and an upper sand mold inserted sequentially from bottom to top, and a sand core embedded between the middle sand mold and the upper sand mold. The lower sand mold is provided with a sprue, and the parting surface of the lower sand mold is provided with two cross-shaped horizontal runners. The two horizontal runners are connected, and the sprue is connected to the position where the two horizontal runners are connected. The middle sand mold is provided with several ingates along the thickness direction. The middle sand mold is provided with two first casting cavities with the same shape as the bottom and side surfaces of the first connecting seat and the second connecting seat. The bottom of the upper sand mold is provided with two second casting cavities with the same shape as the bottom and side surfaces of the first connecting seat and the second connecting seat. The ingates are connected to the first casting cavities. The sand core is located in the first casting cavity. The bottom of the sand core is inserted into the first casting cavity, and the top of the sand core is inserted into the second casting cavity.

4. The 3D printed resin sand casting mold as described in claim 3, characterized in that: The sand core section consists of two sets, which are symmetrically arranged in different first casting cavities. Each sand core section includes sand core No. 1, sand core No. 2, sand core No. 3, sand core No. 4, and sand core No. 5 arranged sequentially along the length of the first casting cavity. Sand core No. 2 and sand core No. 3 are connected by connecting columns. Sand core No. 2, sand core No. 3, and sand core No. 4 have the same structure as the first cavity, the second cavity, and the third cavity. Sand core No. 1 and sand core No. 2 constitute the casting structure of the first connecting member. The gap between sand core No. 5 and sand core No. 5 and sand core No. 4 constitutes the structure of the second connecting member.

5. The 3D printed resin sand casting mold as described in claim 4, characterized in that: Positioning cores are provided at the top and bottom of sand cores No. 2 and No.

4. Elliptical core head holes are provided at the bottom of sand cores No. 3 and No.

4. Positioning holes and elliptical positioning posts are provided corresponding to the first casting cavity. The sand core is positioned by matching the positioning core with the positioning hole and inserting the elliptical core head hole with the elliptical positioning post.

6. The 3D printed resin sand casting mold as described in claim 5, characterized in that: The first casting cavity is provided with multiple first chill holes.

7. The 3D printed resin sand casting mold as described in claim 4, characterized in that: The second casting cavity is provided with a sprue blind hole and multiple second chill holes, and the upper sand mold is also provided with multiple vent holes.

8. The 3D printed resin sand casting mold as described in claim 5, characterized in that: The elliptical positioning post is provided with a draft angle.

9. A casting method, characterized in that, Casting a high-temperature superconducting magnetic levitation landing gear mounting base using the 3D printed resin sand casting mold as described in claim 3 includes the following steps: S1: A mold consisting of a lower sand mold, a middle sand mold, an upper sand mold, and a sand core. S2: The aluminum liquid is injected into the mounting cavity formed by the first casting cavity, the sand mold section, and the second casting cavity through the straight sprue, horizontal sprue, and inner sprue of the lower sand mold to fill the mold; S3: After the filling is completed, increase the pressure on the basis of the filling pressure and hold the pressure to achieve automatic feeding of the casting when the aluminum liquid changes from liquid to solid. S4: After the feeding is completed, the pressure is released, the casting is completed, and the welding is performed to obtain the high-temperature superconducting magnetic levitation landing gear mounting base casting.

10. The casting method as described in claim 9, characterized in that: The temperature of the molten aluminum is 715℃-725℃, and the increased pressure is 50mbar-70mbar.

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