A large blade ceramic core positioning structure

Abstract

This invention discloses a large-blade ceramic core positioning structure, relating to the field of precision casting technology for hollow turbine blades of aero-engines. The large-blade ceramic core positioning structure includes a lower mold, an upper mold, a positioning rod, and a ceramic core. The positioning rod has a support groove in its middle, and a spiral groove on its upper side. A sliding ring is slidably connected to the inner wall of the support groove, and a top rod is fixed to the inner wall of the sliding ring. The top rod has a through groove in its middle, and a connecting structure is provided on the outer surface of the top rod. This large-blade ceramic core positioning structure achieves an adaptive support and compensation effect for the ceramic core. During mold closing and the initial wax injection stage, it provides flexible support to the ceramic core with a small elastic force, avoiding impact damage during mold closing. During wax injection, it automatically increases the support force according to temperature changes to resist ceramic core displacement caused by wax impact and buoyancy, achieving adaptive segmented support and effectively improving the positioning stability of the positioning structure.

Description

Technical Field

[0001] This invention relates to the field of precision casting technology for hollow turbine blades for aero-engines, specifically to a large blade ceramic core positioning structure. Background Technology

[0002] With the continuous improvement of thrust-to-weight ratio and power of aero-engines and ground-based gas turbines, the turbine inlet temperature is constantly increasing, placing increasingly higher demands on the operating temperature and mechanical properties of hot-end components such as turbine blades. The investment casting process for producing hollow turbine blades utilizes a complex internal cooling channel formed by pre-embedding a ceramic core inside the blade. After casting, the ceramic core is removed, allowing the blade to operate reliably at temperatures far exceeding the melting point of metals. In the investment casting process of hollow turbine blades, precise control of the wax pattern wall thickness is both crucial and challenging to ensure the final casting is qualified. Blade wall thickness errors are mainly caused by the positioning error and offset of the ceramic core within the wax mold. This problem is particularly prominent for large turbine blades: on the one hand, the blade size is large and the ceramic core is long, making the core itself prone to bending deformation and positional drift under the impact of gravity and high-temperature molten metal; on the other hand, the wall thickness accuracy requirements for large blades are extremely stringent, and even a small deviation in the positioning of the ceramic core can lead to excessive wall thickness, resulting in blade scrap. Therefore, a positioning structure is needed to accurately and stably position the ceramic core.

[0003] While existing positioning structures can meet the basic needs of daily positioning operations for ceramic cores, they still have many shortcomings in actual use. Because ceramic cores are brittle ceramic materials, their bending strength and impact resistance are extremely limited. It is difficult to apply significant support during the initial placement and mold closing stages, requiring a flexible contact method for initial positioning to avoid localized stress concentration that could lead to core breakage or micro-cracks. However, while this flexible positioning method protects the integrity of the ceramic core, it also results in insufficient clamping force, making it difficult to fully press the ceramic core against the mold's positioning reference surface, significantly reducing positioning reliability. This problem is further exacerbated during subsequent wax injection. Under high pressure, the wax is injected into the mold cavity at a relatively high speed, and the high-speed jet directly impacts the ceramic core surface, generating a large instantaneous impact force. Simultaneously, as the wax gradually fills the cavity, the buoyancy of the wax on the ceramic core also increases. The combined impact force and buoyancy easily overcome the limited clamping force provided by the flexible positioning, causing the ceramic core to shift position or deflect within the cavity. If the ceramic core shifts during the wax injection process, it will directly lead to uneven wall thickness distribution in the wax pattern, which in turn affects the wall thickness accuracy and dimensional consistency of the final casting. In severe cases, it can even cause the blade to be scrapped, significantly reducing the product yield. Therefore, the positioning stability of existing positioning structures is insufficient to meet the reliability requirements of ceramic core positioning in the precision casting of large blades.

[0004] Therefore, it is necessary to invent a large blade ceramic core positioning structure to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a large blade ceramic core positioning structure to solve the problems mentioned in the background art.

[0006] To solve the above technical problems, the present invention provides the following technical solution: a large blade ceramic core positioning structure, including a lower mold, an upper mold, a positioning rod and a ceramic core, wherein a frame groove is provided in the middle of the positioning rod, a spiral groove is provided on the upper side of the frame groove, a sliding ring is slidably connected to the inner wall of the frame groove, a top rod is fixed to the inner wall of the sliding ring, and a through groove is provided in the middle of the top rod; The outer surface of the top rod is provided with a connecting structure, and a support seat is provided on the connecting structure; the connecting structure can move along the height direction of the frame groove with the support seat, so as to adaptively support and compensate the ceramic core during wax injection.

[0007] Preferably, the connecting structure includes an extrusion frame, a first spring fixed to the lower end of the extrusion frame, a turntable fixed to the other end of the first spring, a support plate rotatably connected to the outer surface of the turntable, a support seat provided at the lower end of the support plate, a second spring fixed to the lower end of the support seat, a limit rod slidably connected to the inclined surface of the support seat, a temperature-sensing magnet fixed to the other end of the limit rod, a stabilizing frame slidably connected to the outer surface of the temperature-sensing magnet, a stabilizing groove provided in the middle of the stabilizing frame, and a permanent magnet fixed to one end of the stabilizing groove.

[0008] Preferably, the upper surface of the extrusion frame is rotatably connected to the top rod and the lower surface of the sliding ring. The cross-section of the sliding ring is circular. The outer surface of the sliding ring is slidably connected to the inner wall of the frame groove. The inner wall of the sliding ring is fixed to the lower end of the top rod. The lower end of the extrusion frame is fixed to the upper end of the first spring. The lower end of the first spring is fixed to the upper end of the turntable. The outer surface of the turntable is rotatably connected to the inner wall of the middle part of the support plate. The outer surface of the support plate is slidably connected to the inner wall of the frame groove.

[0009] Preferably, the lower surface of the support plate abuts against the upper end of the support base, the lower end of the support plate is fixed to the upper end of the second spring, the inclined surface of the support plate is slidably connected to the outer surface of the limiting rod, one end of the limiting rod is fixed to the middle of the temperature-sensing magnet, the outer surface of the temperature-sensing magnet is slidably connected to the inner wall of the stabilizing groove, the stabilizing groove is opened in the middle of the stabilizing frame, one side of the permanent magnet is fixed to the inner wall of one end of the stabilizing groove, and one end of the stabilizing frame is fixed to the inner wall of one side of the stabilizing groove.

[0010] Preferably, a protrusion is fixed on one side of the extrusion frame, a threaded rod is fixed in the middle of the extrusion frame, a threaded bracket is threaded to the outer surface of the threaded rod, a fixing rod is fixed on both sides of the threaded bracket, a sliding plate is fixed to the upper end of the two fixing rods, and a heat-resistant silicone suction cup is rotatably connected to the inner wall of the upper end of the through groove.

[0011] Preferably, one end of the protrusion is fixed to one side of the extrusion frame, the outer surface of the protrusion is slidably connected to the inner wall of the spiral groove, the spiral groove is opened on the upper side of the frame groove, the middle part of the extrusion frame is fixed to the lower end of the threaded rod, and the outer surface of the threaded rod is threadedly connected to the middle part of the threaded frame.

[0012] Preferably, the outer surface of the threaded bracket is slidably connected to the lower inner wall of the through groove, the cross-section of the threaded bracket is elliptical, the through groove passes through the middle of the top rod, the lower ends of the two fixing rods are fixed to both sides of the threaded bracket, the upper ends of the two fixing rods are fixed to both sides of the slide plate, the outer surface of the slide plate is slidably connected to the upper inner wall of the through groove, and the outer surface of the heat-resistant silicone suction cup is rotatably connected to the upper inner wall of the through groove.

[0013] Preferably, a fixed plate is fixed to the lower end of the second spring, a fixed frame is fixed to the lower end of the fixed plate, two connecting frames are rotatably connected to the lower end of the fixed frame, a connecting seat is rotatably connected to the lower end of each of the two connecting frames, and a squeeze rod is fixed to the other end of each of the two connecting seats.

[0014] Preferably, the upper end of the fixing plate is fixed to the lower end of the second spring, the outer surface of the fixing plate is slidably connected to the inner wall of the frame groove, the lower end of the fixing plate is fixed to the upper end of the fixing frame, and the vertical section of the fixing frame is U-shaped.

[0015] Preferably, the lower end of the fixed frame is rotatably connected to the near ends of two connecting frames, the far ends of the two connecting frames are rotatably connected to the near ends of two connecting seats, the far ends of the two connecting seats are fixed to the near ends of two extrusion rods, and the two extrusion rods pass through both sides of the lower end of the frame groove.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention achieves an adaptive support compensation effect for the ceramic core. In the early stage of mold closing and wax injection, the ceramic core is flexibly supported with a small elastic force to avoid impact damage during mold closing. During the wax injection process, the support force is automatically increased according to the temperature change to resist the ceramic core displacement caused by wax impact and buoyancy. This realizes adaptive segmented support and effectively improves the positioning stability of the positioning structure. (2) The present invention achieves the effect of adsorption and fixation. It utilizes the principle of negative pressure adsorption to form a stable adsorption fit between the heat-resistant silicone suction cup and the surface of the ceramic core. Without changing the structure of the ceramic core itself or introducing additional connecting parts, a reliable adsorption constraint is formed between the positioning structure and the ceramic core, which effectively resists the tendency of the ceramic core to shift due to the impact of wax liquid and buoyancy. In the dewaxing process, it is only necessary to overcome the adsorption force to achieve the separation of the positioning structure from the wax mold. No destructive dismantling is required, which ensures the process requirement of separable demolding and significantly improves the overall use effect of the positioning structure. (3) The present invention achieves a stable insertion effect, effectively increases the frictional force between the positioning structure and the insertion hole, and makes the positioning rod form a self-locking mating fit in the slot. This avoids the problem of inconvenience in disassembly and assembly caused by the threaded connection method, and overcomes the defect of easy loosening and falling off due to insufficient friction when the gap fit is inserted. Thus, under the premise of ensuring that the positioning structure can be easily disassembled and assembled, the anti-loosening performance of the positioning structure is significantly improved. Attached Figure Description

[0017] Figure 1 This is a cross-sectional structural diagram of the ceramic core for mold clamping support of the present invention; Figure 2 This is a schematic diagram of the positioning rod structure of the present invention; Figure 3 This is a partial structural cross-sectional view of the present invention; Figure 4 For the present invention Figure 3 Enlarged view of the structure of section A in the middle; Figure 5 For the present invention Figure 3 Enlarged view of the structure of section B in the middle; Figure 6 For the present invention Figure 3 Enlarged view of the structure of section C; Figure 7 This is a partial structural diagram of the present invention; Figure 8 This is a cross-sectional view of the positioning rod of the present invention.

[0018] In the diagram: 1. Lower mold; 2. Upper mold; 3. Positioning rod; 4. Ceramic core; 5. Frame groove; 6. Spiral groove; 7. Sliding ring; 8. Ejector rod; 9. Through groove; 10. Extrusion frame; 11. First spring; 12. Turntable; 13. Support plate; 14. Support seat; 15. Second spring; 16. Limiting rod; 17. Temperature-sensing magnet; 18. Stabilizing frame; 19. Stabilizing groove; 20. Permanent magnet; 21. Protrusion; 22. Threaded rod; 23. Threaded frame; 24. Fixing rod; 25. Sliding plate; 26. Heat-resistant silicone suction cup; 27. Fixing plate; 28. Fixing frame; 29. ​​Connecting frame; 30. Connecting seat; 31. Extrusion rod. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] This embodiment provides a large blade ceramic core positioning structure; Please see Figure 1 - Figure 8 As shown, it includes a lower mold 1, an upper mold 2, a positioning rod 3 and a ceramic core 4. The positioning rod 3 has a support groove 5 in the middle, and a spiral groove 6 is provided on the upper side of the support groove 5. A sliding ring 7 is slidably connected to the inner wall of the support groove 5. A top rod 8 is fixed to the inner wall of the sliding ring 7. A through groove 9 is provided in the middle of the top rod 8. The outer surface of the top rod 8 is provided with a connecting structure, which includes a compression frame 10. A first spring 11 is fixed to the lower end of the compression frame 10, and a turntable 12 is fixed to the other end of the first spring 11. A support plate 13 is rotatably connected to the outer surface of the turntable 12. A support seat 14 is provided at the lower end of the support plate 13, and a second spring 15 is fixed to the lower end of the support seat 14. A limit rod 16 is slidably connected to the inclined surface of the support seat 14. A temperature-sensing magnet 17 is fixed to the other end of the limit rod 16. A stabilizing frame 18 is slidably connected to the outer surface of the temperature-sensing magnet 17. A stabilizing groove 19 is opened in the middle of the stabilizing frame 18, and a permanent magnet 20 is fixed to one end of the stabilizing groove 19. 7 is a temperature-sensitive ferrite material prepared by powder metallurgy sintering process, with a defined Curie temperature. The temperature of the wax liquid in the wax injection process is usually 70℃ to 75℃, and the working temperature of the mold closing space can reach 85℃ to 90℃ after being heated. The Curie temperature of the temperature-sensitive magnet 17 can be customized and matched to this range according to the specific wax injection temperature. Under normal conditions, the temperature-sensitive magnet 17 has strong magnetism and is set in a way that is opposite to the same pole with the permanent magnet 20 fixed on the inner wall of the stabilizing groove 19. The two generate a repulsive force, which pushes the temperature-sensitive magnet 17 to drive the limiting rod 16 to abut against the inclined surface of the support seat 14, so that the support seat 14 compresses the second spring 15 and keeps it in an energy storage state. When wax is injected, the temperature rises to the Curie temperature of the temperature-sensing magnet 17, and its magnetism weakens sharply until it disappears. The repulsive force between it and the permanent magnet 20 disappears simultaneously, and the elastic restoring force of the second spring 15 is released, driving the support base 14 to move upward, thereby achieving adaptive support compensation for the ceramic core 4. As a passive temperature control element, the temperature-sensing magnet 17 can complete temperature sensing and action triggering without the need for an external power source or air source.

[0021] Please refer to it again. Figure 1 - Figure 8As shown, the upper surface of the extrusion frame 10 is rotatably connected to the top rod 8 and the lower surface of the sliding ring 7. The cross-section of the sliding ring 7 is circular. The outer surface of the sliding ring 7 is slidably connected to the inner wall of the frame groove 5. The inner wall of the sliding ring 7 is fixed to the lower end of the top rod 8. The lower end of the extrusion frame 10 is fixed to the upper end of the first spring 11. The lower end of the first spring 11 is fixed to the upper end of the turntable 12. The outer surface of the turntable 12 is rotatably connected to the inner wall of the middle part of the support plate 13. The outer surface of the support plate 13 is slidably connected to the inner wall of the frame groove 5. The lower surface of the support plate 13 abuts against the upper end of the support base 14. The lower end of the support plate 13 is fixed to the upper end of the second spring 15. The inclined surface of the support plate 13 is slidably connected to the outer surface of the limiting rod 16. One end of the limiting rod 16 is fixed to the middle of the temperature-sensing magnet 17. The outer surface of the temperature-sensing magnet 17 is slidably connected to the inner wall of the stabilizing groove 19. The stabilizing groove 19 is opened in the middle of the stabilizing frame 18. One side of the permanent magnet 20 is fixed to the inner wall of one end of the stabilizing groove 19. One end of the stabilizing frame 18 is fixed to the inner wall of one side of the frame groove 5.

[0022] The specific implementation process is as follows: First, the positioning rod 3 is inserted into the insertion holes of the lower mold 1 and the upper mold 2. Before mold closing, the ceramic core 4 is placed on the top of several ejector rods 8, and each ejector rod 8 is slidably connected to the inner wall of the top of the corresponding positioning rod 3. When the mold closes, the upper mold 2 and the lower mold 1 gradually close. After the ceramic core 4 is pressed, it pushes the ejector rod 8 in contact with it to move. The ejector rod 8 drives the sliding ring 7 fixed on it to slide along the inner wall of the frame groove 5 opened in the middle of the positioning rod 3. When the sliding ring 7 moves, it squeezes the extrusion frame 10 that cooperates with it, so that the extrusion frame 10 slides along the inner wall of the frame groove 5, thereby compressing the first spring 11 fixed on the extrusion frame 10. The other end of the first spring 11 is fixed on the turntable 12, and the outer surface of the turntable 12 is rotatably connected to the inner wall of the support plate 13. The support plate 13 abuts against the support base 14. In the initial stage of mold closing, the first spring 11 generates elastic restoring force after being compressed, which provides flexible support to the ceramic core 4 through the extrusion frame 10, the sliding ring 7 and the ejector rod 8, so as to avoid the ceramic core 4 from breaking due to the impact of mold closing; During wax injection, high-temperature wax is injected into the mold cavity, raising the temperature within the mold-closing space. A stabilizing groove 19 is formed inside the stabilizing frame 18, which is fixed to the inner wall of one side of the frame groove 5. A temperature-sensitive magnet 17 is slidably connected to the inner wall of the stabilizing groove 19, and a permanent magnet 20 is fixed to the inner wall of one end of the stabilizing groove 19. Before wax injection, the temperature-sensitive magnet 17 has strong magnetism at room temperature, generating a repulsive force with the permanent magnet 20. This repulsive force pushes the temperature-sensitive magnet 17 to the other end of the stabilizing groove 19, causing the limiting rod 16 fixed in the middle of the temperature-sensitive magnet 17 to abut against the inclined surface of the support base 14. This causes the support base 14 to overcome the elastic force of the second spring 15 and compress the second spring 15, keeping it in a compressed, energy-storing state. As the wax injection temperature rises to the Curie temperature of the temperature-sensitive magnet 17, the magnetism of the temperature-sensitive magnet 17 gradually weakens until it essentially disappears, and the repulsive force between it and the permanent magnet 20 decreases synchronously and eventually disappears. During this process, the elastic restoring force of the second spring 15 gradually exceeds the repulsive force, driving the support seat 14 to move. Through the cooperation of the limiting rod 16 and the inclined plane, the temperature-sensing magnet 17 slides closer to the permanent magnet 20 in the stabilizing groove 19. The moving support seat 14 squeezes the support plate 13, causing the turntable 12, which is rotatably connected to the support plate 13, to move synchronously, thereby compressing the first spring 11 a second time, further increasing the elastic restoring force of the first spring 11. The increased elastic force is transmitted to the ceramic core 4 through the extrusion frame 10, the sliding ring 7, and the ejector rod 8. At this time, the ceramic core 4 is in a high-temperature wax-encased environment, and its crack resistance is improved compared to room temperature. The increased support force will not cause damage to the ceramic core 4, thus achieving an adaptive support compensation effect for the ceramic core. In the early stages of mold closing and wax injection, a smaller elastic force is used to flexibly support the ceramic core 4 to avoid impact damage during mold closing. During the wax injection process, the support force automatically increases according to temperature changes to resist the ceramic core displacement caused by wax impact and buoyancy, realizing adaptive segmented support and effectively improving the positioning stability of the positioning structure. Example 2

[0023] Existing positioning structures, when used for support and positioning in contact with the ceramic core, face challenges in achieving a secure connection due to the need to consider the separability of the positioning structure from the ceramic core and wax model during subsequent dewaxing processes. The positioning components can only form a separable fit with the ceramic core through abutment, resulting in limited connection strength, insufficient positioning constraint, and unsatisfactory positioning effects. During wax injection, the impact of wax or buoyancy on the ceramic core fails to provide sufficient constraint to resist core displacement, thus affecting the accuracy of the wax model wall thickness and the dimensional consistency of the casting. Therefore, adsorption positioning of the ceramic core is necessary to effectively improve the overall performance of the positioning structure while ensuring separability for demolding.

[0024] Please see Figure 1 - Figure 8 As shown, the adsorption and fixation function has been added based on Example 1; Please refer to it again. Figure 1 - Figure 8 As shown, a protrusion 21 is fixed on one side of the extrusion frame 10, a threaded rod 22 is fixed in the middle of the extrusion frame 10, a threaded bracket 23 is threadedly connected to the outer surface of the threaded rod 22, and fixing rods 24 are fixed on both sides of the threaded bracket 23. A sliding plate 25 is fixed to the upper end of the two fixing rods 24. A heat-resistant silicone suction cup 26 is rotatably connected to the inner wall of the upper end of the through groove 9. One end of the protrusion 21 is fixed to one side of the extrusion frame 10, and the outer surface of the protrusion 21 is slidably connected to the inner wall of the spiral groove 6. The spiral groove 6 is opened on the upper side of the frame groove 5. The middle of the extrusion frame 10 is fixed The threaded rod 22 is fixed at the lower end of the threaded rod 22. The outer surface of the threaded rod 22 is threadedly connected to the middle of the threaded frame 23. The outer surface of the threaded frame 23 is slidably connected to the lower inner wall of the through groove 9. The cross-section of the threaded frame 23 is elliptical. The through groove 9 passes through the middle of the top rod 8. The lower ends of the two fixing rods 24 are fixed to both sides of the threaded frame 23. The upper ends of the two fixing rods 24 are fixed to both sides of the slide plate 25. The outer surface of the slide plate 25 is slidably connected to the upper inner wall of the through groove 9. The outer surface of the heat-resistant silicone suction cup 26 is rotatably connected to the upper inner wall of the through groove 9.

[0025] The specific implementation process is as follows: The push rod 8, which is pressed by the ceramic core 4, moves, causing the push rod 8 and the sliding ring 7 to press the extrusion frame 10, which moves synchronously. When the extrusion frame 10 moves, the protrusion 21 fixed on one side moves along with it. The outer surface of the protrusion 21 is slidably connected to the inner wall of the spiral groove 6. Under the guidance of the spiral groove 6, the protrusion 21 rotates synchronously as it moves. The sliding ring 7 is fixed to the upper end of the first spring 11, and the lower end of the first spring 11 is fixed to the turntable 12. The turntable 12 is rotatably connected to the support plate 13, so that the extrusion frame 10 can drive the first spring 11 to rotate. The rotating extrusion frame 10 drives the threaded rod 22 fixed in its middle to rotate synchronously. The other end of the threaded rod 22 is rotatably connected to the inner wall of the through groove 9 opened in the middle of the push rod 8, so that the threaded rod 22 maintains stable rotation. When the threaded rod 22 rotates, it drives the threaded frame 23 connected to its outer surface to slide stably under the limitation of the inner wall of the through groove 9. The threaded bracket 23 drives the slide plate 25 to slide synchronously through the fixing rods 24 fixed on both sides of it. The slide plate 25 also slides stably under the limit of the inner wall of the through groove 9. When placing the ceramic core 4, the ceramic core 4 is already in contact with the heat-resistant silicone suction cup 26, which is rotatably connected to the inner wall of the top of the through groove 9, and the heat-resistant silicone suction cup 26 is adsorbed onto the surface of the ceramic core 4. As the slide plate 25 slides, the volume of the sealed area formed between the through groove 9 and the heat-resistant silicone suction cup 26 increases, and the negative pressure is enhanced, so that the heat-resistant silicone suction cup 26 is firmly adsorbed onto the ceramic core 4, achieving the effect of adsorption and fixation. The principle of negative pressure adsorption makes the heat-resistant silicone suction cup 26 and the surface of the ceramic core 4 form a stable adsorption fit. Without changing the structure of the ceramic core 4 itself or introducing additional connecting parts, a reliable adsorption constraint force is formed between the positioning structure and the ceramic core 4, which effectively resists the tendency of the ceramic core to shift due to wax impact and buoyancy. In the dewaxing process, only the adsorption force needs to be overcome to achieve the separation of the positioning structure from the wax mold, without destructive removal, ensuring the process requirement of separable demolding and significantly improving the overall use effect of the positioning structure. Example 3

[0026] When a positioning structure is inserted into the mold's insertion hole, a threaded connection, while providing a secure connection, makes subsequent disassembly and maintenance inconvenient, affecting mold changeover efficiency. Conversely, a clearance fit connection, while convenient for assembly and disassembly, results in low friction between the mating surfaces, making the positioning structure prone to detachment during mold closing and wax injection due to vibration or external forces, thus compromising positioning reliability. Therefore, it is necessary to increase the frictional force between the positioning structure and the insertion hole while ensuring ease of assembly and disassembly to improve the positioning structure's resistance to detachment.

[0027] Please see Figure 1 - Figure 8 As shown, a stable plug-in function has been added based on Embodiment 1; Please refer to it again. Figure 1 - Figure 8 As shown, a fixed plate 27 is fixed to the lower end of the second spring 15, and a fixed frame 28 is fixed to the lower end of the fixed plate 27. Two connecting frames 29 are rotatably connected to the lower end of the fixed frame 28. Connecting seats 30 are rotatably connected to the lower ends of the two connecting frames 29. Extrusion rods 31 are fixed to the other ends of the two connecting seats 30. The upper end of the fixed plate 27 is fixed to the lower end of the second spring 15. The outer surface of the fixed plate 27 is slidably connected to the inner wall of the frame groove 5. The lower end of the fixed plate 27 is fixed to the upper end of the fixed frame 28. The vertical section of the fixed frame 28 is U-shaped. The lower end of the fixed frame 28 is rotatably connected to the near ends of the two connecting frames 29. The far ends of the two connecting frames 29 are rotatably connected to the near ends of the two connecting seats 30. The far ends of the two connecting seats 30 are fixed to the near ends of the two extrusion rods 31. The two extrusion rods 31 pass through both sides of the lower end of the frame groove 5.

[0028] The specific implementation process is as follows: When the positioning rod 3 is inserted into the slot between the lower mold 1 and the upper mold 2, the inner wall of the slot squeezes the two extrusion rods 31, causing the two extrusion rods 31 to move closer to each other. The two extrusion rods 31 drive the two connecting seats 30 fixed at their near ends to move closer simultaneously. The two connecting seats 30 are rotatably connected to the two connecting frames 29 at their near ends, which in turn drive the fixed frame 28 rotatably connected at the near ends of the two connecting frames 29 to move upward. Under the limitation of the inner wall of the frame groove 5 opened in the middle of the positioning rod 3, the fixed frame 28 drives the fixed plate 27 fixed at its upper end to move upward simultaneously. The fixed plate 27 compresses the second spring 15 sleeved on the upper end of the positioning rod 3. At this time, the temperature-sensing magnet 17 is still in a cooled state. The repulsive force between it and the permanent magnet 20 is greater than the elastic force of the second spring 15 after being squeezed by the fixed plate 27, causing the second spring 15 to be further compressed and store greater elastic potential energy. When the positioning rod 3 is inserted into the predetermined position in the slot, the second spring 15 is compressed to the maximum extent. Its elastic restoring force is transmitted to the two extrusion rods 31 through the fixed plate 27, the fixed frame 28, the connecting frame 29 and the connecting seat 30. Under the action of the elastic force of the second spring 15, the two extrusion rods 31 are pressed against the inner wall of the slot, thereby forming a stable mating fit between the positioning rod 3 and the slot, achieving a stable insertion effect. This effectively increases the mating friction between the positioning structure and the insertion hole, allowing the positioning rod 3 to form a self-locking mating fit in the slot. This avoids the inconvenience of disassembly and assembly caused by the threaded connection method, and overcomes the defect of easy loosening and falling off due to insufficient friction when using a clearance fit. Thus, while ensuring that the positioning structure can be easily disassembled and assembled, the anti-loosening performance of the positioning structure is significantly improved.

[0029] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A large blade ceramic core positioning structure, comprising a lower mold (1), an upper mold (2), a positioning rod (3), and a ceramic core (4), characterized in that: The positioning rod (3) has a frame groove (5) in the middle, and a spiral groove (6) is provided on the upper side of the frame groove (5). A sliding ring (7) is slidably connected to the inner wall of the frame groove (5). A top rod (8) is fixed to the inner wall of the sliding ring (7). A through groove (9) is provided in the middle of the top rod (8). The top rod (8) has a connecting structure on its outer surface, and a support seat (14) is provided on the connecting structure. The connecting structure can move along the height direction of the support seat (14) in the groove (5) so as to adaptively support and compensate the ceramic core (4) during wax injection.

2. The large blade ceramic core positioning structure according to claim 1, characterized in that: The connection structure includes an extrusion frame (10), a first spring (11) is fixed at the lower end of the extrusion frame (10), a turntable (12) is fixed at the other end of the first spring (11), a support plate (13) is rotatably connected to the outer surface of the turntable (12), a support seat (14) is provided at the lower end of the support plate (13), a second spring (15) is fixed at the lower end of the support seat (14), a limit rod (16) is slidably connected to the inclined surface of the support seat (14), a temperature-sensing magnet (17) is fixed at the other end of the limit rod (16), a stabilizing frame (18) is slidably connected to the outer surface of the temperature-sensing magnet (17), a stabilizing groove (19) is provided in the middle of the stabilizing frame (18), and a permanent magnet (20) is fixed at one end of the stabilizing groove (19).

3. The large blade ceramic core positioning structure according to claim 2, characterized in that: The upper surface of the extrusion frame (10) is rotatably connected to the top rod (8) and the lower surface of the sliding ring (7). The cross-section of the sliding ring (7) is circular. The outer surface of the sliding ring (7) is slidably connected to the inner wall of the frame groove (5). The inner wall of the sliding ring (7) is fixed to the lower end of the top rod (8). The lower end of the extrusion frame (10) is fixed to the upper end of the first spring (11). The lower end of the first spring (11) is fixed to the upper end of the turntable (12). The outer surface of the turntable (12) is rotatably connected to the inner wall of the middle part of the support plate (13). The outer surface of the support plate (13) is slidably connected to the inner wall of the frame groove (5).

4. The large blade ceramic core positioning structure according to claim 2, characterized in that: The lower surface of the support plate (13) abuts against the upper end of the support base (14). The lower end of the support plate (13) is fixed to the upper end of the second spring (15). The inclined surface of the support plate (13) is slidably connected to the outer surface of the limiting rod (16). One end of the limiting rod (16) is fixed to the middle of the temperature-sensing magnet (17). The outer surface of the temperature-sensing magnet (17) is slidably connected to the inner wall of the stabilizing groove (19). The stabilizing groove (19) is opened in the middle of the stabilizing frame (18). One side of the permanent magnet (20) is fixed to the inner wall of one end of the stabilizing groove (19). One end of the stabilizing frame (18) is fixed to the inner wall of one side of the frame groove (5).

5. The large blade ceramic core positioning structure according to claim 2, characterized in that: A protrusion (21) is fixed on one side of the extrusion frame (10), a threaded rod (22) is fixed in the middle of the extrusion frame (10), a threaded frame (23) is threaded on the outer surface of the threaded rod (22), a fixing rod (24) is fixed on both sides of the threaded frame (23), a sliding plate (25) is fixed on the upper end of the two fixing rods (24), and a heat-resistant silicone suction cup (26) is rotatably connected to the inner wall of the upper end of the through groove (9).

6. The large blade ceramic core positioning structure according to claim 5, characterized in that: One end of the protrusion (21) is fixed to one side of the extrusion frame (10). The outer surface of the protrusion (21) is slidably connected to the inner wall of the spiral groove (6). The spiral groove (6) is opened on the upper side of the frame groove (5). The middle part of the extrusion frame (10) is fixed to the lower end of the threaded rod (22). The outer surface of the threaded rod (22) is threadedly connected to the middle part of the threaded frame (23).

7. A large blade ceramic core positioning structure according to claim 5, characterized in that: The outer surface of the threaded bracket (23) is slidably connected to the inner wall of the lower side of the through groove (9). The cross section of the threaded bracket (23) is elliptical. The through groove (9) passes through the middle of the top rod (8). The lower ends of the two fixing rods (24) are fixed to both sides of the threaded bracket (23). The upper ends of the two fixing rods (24) are fixed to both sides of the slide plate (25). The outer surface of the slide plate (25) is slidably connected to the inner wall of the upper side of the through groove (9). The outer surface of the heat-resistant silicone suction cup (26) is rotatably connected to the inner wall of the upper end of the through groove (9).

8. A large blade ceramic core positioning structure according to claim 2, characterized in that: The second spring (15) has a fixed plate (27) fixed at its lower end. The fixed plate (27) has a fixed frame (28) fixed at its lower end. The fixed frame (28) has two connecting frames (29) rotatably connected at its lower end. The two connecting frames (29) have connecting seats (30) rotatably connected at their lower ends. The two connecting seats (30) have extrusion rods (31) fixed at their other ends.

9. A large blade ceramic core positioning structure according to claim 8, characterized in that: The upper end of the fixed plate (27) is fixed to the lower end of the second spring (15), the outer surface of the fixed plate (27) is slidably connected to the inner wall of the frame groove (5), the lower end of the fixed plate (27) is fixed to the upper end of the fixed frame (28), and the vertical section of the fixed frame (28) is U-shaped.

10. A large blade ceramic core positioning structure according to claim 8, characterized in that: The lower end of the fixed frame (28) is rotatably connected to the near ends of two connecting frames (29), the far ends of the two connecting frames (29) are rotatably connected to the near ends of two connecting seats (30), the far ends of the two connecting seats (30) are fixed to the near ends of two extrusion rods (31), and the two extrusion rods (31) pass through both sides of the lower end of the frame groove (5).

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