Modular low pressure casting mold

Abstract

The application discloses a kind of modular low-pressure casting mould, it is related to low-pressure casting mould technical field, to solve the technical problem that small step of sprue module and cavity module flow channel junction influences module service life and casting quality.The application improves casting quality and efficiency by multiple structures synergies;Sprue pipe fittings eliminate flow channel step with shape memory alloy, optimize metal liquid flow, reduce defects and prolong module life;Compression element utilizes dynamic force to drive sealing sleeve, cooperates with expansion element physical lock, strengthens sealing effect;Internal pressure structure compensates by multiple thrust, ensures uniform sealing, adapts pressure fluctuation;Each component linkage does not need additional power, reduce energy consumption, and adapt to a variety of products, reduce replacement and downtime, reduce production cost comprehensively, meet high-precision casting demand, significantly improve mould reliability and production efficiency.

Description

Technical Field

[0001] This invention relates to the field of low-pressure casting mold technology, and more specifically, to a modular low-pressure casting mold. Background Technology

[0002] Modular low-pressure casting molds significantly improve the efficiency of switching between castings of different specifications by disassembling the overall mold into independently replaceable units such as gating modules and cavity modules, and are widely used in automotive parts, aerospace components and other fields. However, in actual production, due to factors such as machining accuracy errors and cumulative assembly tolerances, small steps (usually 0.1-0.5mm) are easily formed at the junction of the runner and cavity modules.

[0003] These tiny steps can have a significant negative impact on the flow of molten metal: the high-speed flow of molten metal (especially low-viscosity molten metals such as aluminum alloys and magnesium alloys) will continuously erode the steps, causing accelerated wear on the runner surface after long-term use, forming deeper pits or protrusions, further deteriorating the flow conditions. According to statistics, the average service life of the runner modules of traditional modular molds is only 60%-70% of that of integral molds. Frequent module replacements not only increase production costs but also reduce production efficiency due to downtime for maintenance.

[0004] Furthermore, the turbulence at the steps in the molten metal can entrain gas, leading to defects such as porosity and looseness inside the casting, affecting the product's mechanical properties. Existing solutions mostly rely on improving machining accuracy or increasing assembly and debugging time, but these are limited by manufacturing process capabilities and cannot completely eliminate the steps, significantly increasing mold manufacturing costs. With the low-pressure casting industry's increasing demands for casting quality and production efficiency, there is an urgent need to develop a modular mold structure that can effectively eliminate flow channel steps and improve the flow state of the molten metal. This is the core research background and innovation direction of this patented technology. Therefore, we propose a modular low-pressure casting mold. Summary of the Invention

[0005] The purpose of this invention is to provide a modular low-pressure casting mold to solve the technical problem that the small steps at the junction of the gating module and the cavity module affect the service life and casting quality of the module.

[0006] To solve the above technical problems, the present invention provides the following technical solution: a modular low-pressure casting mold, including an upper casting module and a lower casting module, wherein a cavity is formed between the upper casting module and the lower casting module, a grounding frame is provided on the outer periphery of the upper casting module, and a lifting hydraulic rod is connected between the grounding frame and the upper casting module;

[0007] The bottom of the casting lower module is provided with a gating module, and a sealing connection ring for connecting with an external crucible is provided below the gating module. The gating module and the grounding frame are limited to slide. A liquid riser extending into the crucible is connected to the bottom of the gating module. A gating connector is provided inside the gating module.

[0008] The gating connector includes a gating pipe that connects the gating between the casting lower module and the gating module. The lower half and upper half of the gating pipe are respectively a gating spiral section and a gating straight pipe section. The connection between the gating spiral section and the gating straight pipe section is located at the gating connection point between the casting lower module and the gating module. The gating spiral section is spiral in shape. The gating pipe is made of shape memory alloy. The phase transformation temperature of the gating pipe is higher than the working temperature of the mold.

[0009] Preferably, the ends of the spiral section and the straight pipe section of the gating system are corrugated, the straight pipe section of the gating system has a protrusion on its outer periphery, and the straight pipe section of the gating system has a positioning pressure plate fixed to the top of the gating module.

[0010] Preferably, the bottom of the gating module and the top of the sealing connecting ring are both connected to a sealing ring. The outer periphery of the sealing ring is provided with a ring shell, and the inner side wall of the ring shell is provided with a sealing sleeve. The sealing sleeve is made of an elastic metal material, and the inner side of the sealing sleeve is provided with a rubber layer. The top of the sealing sleeve is connected to a pressure ring.

[0011] Preferably, a compression member is provided between the straight pipe section of the gating system and the ring shell. The compression member includes a spring slide plate connected to the straight pipe section of the gating system. The spring slide plate slides in a limited manner with the gating module. Multiple connecting plates are connected to the top of the spring slide plate. The connecting plates pass through the gating module and can move in a limited manner along the vertical direction of the gating module. A spring-loaded outer ring is connected between the outer peripheries of the multiple connecting plates.

[0012] Preferably, the outer ring of the elastic sliding ring has a C-shaped cross-section, and an integrally annular overlapping spring sheet is provided between the outer ring of the elastic sliding ring and the pressure ring. The overlapping spring sheet has a multi-wave structure, and the crest of the overlapping spring sheet is attached to one side of the sealing sleeve. The overlapping spring sheet is made of elastic metal.

[0013] Preferably, the inner side of the sealing sleeve is further provided with an expansion member, which consists of an expansion protrusion and an inner recess. The expansion protrusion is two hump shapes protruding inward. The expansion protrusion is made of shape memory polymer or piezoelectric material. The inner recess is opened on the outer wall of the sealing ring.

[0014] Preferably, the outer wall of the sealing ring has an inner pressure cavity, which is composed of a buffer section, an inner pressure arc section and an outer pressure section, and an inner pressure component is provided inside the inner pressure cavity.

[0015] Preferably, the inner pressure component includes multiple inner pressure arc plates, which are distributed in a ring array, and one side of each inner pressure arc plate is connected to the outer arc side of the sealing sleeve.

[0016] Preferably, the inner pressure arc plate is composed of an inner arc body and a side pressure convex angle. The side pressure convex angle is located at the top of the inner arc body, and the side pressure convex angle is a convex arc shape. The side pressure convex angle fits into the inner pressure arc segment.

[0017] Preferably, an inner pressure spring block is connected between adjacent inner pressure arc plates, and the inner pressure spring block and the inner pressure arc plate form a ring. The inner pressure spring block has a structure in which the thickness gradually decreases from both sides to the center, and the inner pressure spring block is made of elastic material.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. This invention utilizes shape memory alloy for the gating pipe fittings. After pretreatment, the corrugated ends of the spiral and straight pipe sections can tightly fit the inner wall of the flow channel. This flexibility eliminates minor steps caused by machining or assembly, ensuring consistent flow channel diameter. When molten metal flows through the spiral section, the spiral structure absorbs impact kinetic energy, slows flow velocity fluctuations, and avoids defects such as porosity and cold shuts caused by turbulence. Simultaneously, it reduces flow channel erosion and wear, extending the module's lifespan to the level of an integral mold, reducing replacement frequency and cost. This solves the problem of minor steps at the connection between the gating module and the cavity module affecting module lifespan and casting quality.

[0020] 2. This invention also transmits the dynamic force generated by the vibration of the gating pipe through the compression component via the spring slide, connecting plate and spring slide outer ring, driving the stacked spring sheet (multiple wave-shaped) to compress the sealing sleeve. The sealing sleeve is made of elastic metal material, and the inner rubber layer tightly wraps the sealing ring after being compressed. It automatically enhances the sealing performance during the casting process, and can achieve "wave-compression-seal" linkage without additional power, preventing metal leakage or gas infiltration, ensuring stable transmission of 0.2-0.5MPa pressure in the crucible, and improving the reliability of low-pressure casting.

[0021] 3. The present invention also uses the expansion protrusion (double hump structure) on the inner side of the sealing sleeve to be made of shape memory polymer and piezoelectric material composite. When the stacked elastic sheet is squeezed, the piezoelectric effect generates a weak current. The shape memory polymer is heated and restores its expansion shape, so that the protrusion is precisely embedded into the inner concave opening of the sealing ring to form a physical lock. The dual effect enhances the tightness of the sealing sleeve and the sealing ring, overcomes the problem of weak sealing effect of traditional rubber layer, and adapts to the high sealing requirements under dynamic pressure environment.

[0022] 4. This invention also utilizes the inner pressure arc plate to compress the inner pressure cavity inward as the sealing sleeve deforms. The inner arc body converts the radial force into a thrust on the inner side of the sealing ring. The lateral pressure convex angle generates a lateral component force when the sealing sleeve is subjected to uneven force, compensating for the sealing force. The inner pressure spring block between adjacent arc plates is compressed and bent, generating a reverse thrust to drive the arc plate to further compress, forming a triple action of "direct thrust + compensating thrust + elastic reverse thrust", ensuring uniform pressure on the annular sealing surface, avoiding local gap leakage, and adapting to pressure fluctuation conditions.

[0023] 5. This invention eliminates runner steps through gating pipe fittings, reducing casting defects and extending module life; the compaction component, expansion component, and internal pressure structure work together to strengthen the seal, ensuring stable pressure; all components utilize the kinetic energy of molten metal flow or deformation force to achieve linkage, requiring no additional power and reducing energy consumption. The mold is adaptable to different product specifications, reducing replacement frequency and downtime, comprehensively improving production efficiency, reducing casting defect rate and manufacturing costs, and meeting the needs of high-precision casting. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention.

[0025] Figure 2 This is a schematic diagram of the casting module in this invention.

[0026] Figure 3 This is a half-sectional structural diagram of the gating module in this invention.

[0027] Figure 4 This is a schematic diagram of the gating connector in this invention.

[0028] Figure 5 This is a schematic diagram of the connection structure between the compression component and the sealing ring in this invention.

[0029] Figure 6 This is a schematic diagram of the sealing ring in this invention.

[0030] Figure 7 This is a schematic diagram of a half-section of the ring shell in this invention.

[0031] Figure 8 This is a schematic diagram of the compression component in this invention.

[0032] Figure 9 This is a schematic diagram of the sealing sleeve in this invention.

[0033] Figure 10 This is a schematic diagram of the structure between the sealing sleeve and the sealing ring in this invention.

[0034] Figure 11 In this invention Figure 10 Enlarged view of the structure at point A in the middle.

[0035] Figure 12 This is a schematic diagram of the internal pressure component in this invention.

[0036] Figure 13 In this invention Figure 12 Enlarged view of the structure at point B in the middle.

[0037] Explanation of the labels in the diagram:

[0038] 1. Casting upper module; 2. Casting lower module; 3. Grounding frame; 4. Lifting hydraulic rod; 5. Sprue module; 6. Sealing connecting ring; 7. Lifting pipe; 8. Sprue connector; 9. Sealing ring; 10. Ring shell; 11. Sealing sleeve; 12. Pressure ring; 13. Compactor; 14. Expansion piece; 15. Inner pressure cavity; 16. Inner pressure piece;

[0039] 801. Sprue fitting; 8011. Spiral section of sprue; 8012. Straight section of sprue; 802. Protrusion; 803. Positioning plate; 131. Spring slide; 132. Connecting plate; 133. Spring outer ring; 134. Overlapping spring; 141. Expansion protrusion; 142. Inner notch; 151. Buffer section; 152. Inner pressure arc section; 153. Outer pressure section; 161. Inner pressure arc plate; 1611. Inner arc body; 1612. Side pressure protrusion; 162. Inner pressure spring block. Detailed Implementation

[0040] like Figures 1 to 13 As shown, this invention relates to a modular low-pressure casting mold. The upper casting module 1 and the lower casting module 2 serve as the core forming components of the mold, forged from high-strength hot-work die steel (such as H13). Aging treatment ensures dimensional stability under high temperature and high pressure conditions. After the two modules are closed, they form a cavity consistent with the shape of the casting. The inner wall of the cavity is mirror-polished (Ra≤0.8μm) to reduce the resistance to molten metal flow and ensure the surface finish of the casting. The top of the upper casting module 1 integrates an venting groove (diameter...). (1.2-1.5mm) can expel air and gas from inside the mold cavity during the filling process, avoiding porosity defects in the casting.

[0041] The grounding frame 3 on the outer periphery of the upper casting module 1 is a rectangular frame structure, welded from Q345B low-alloy high-strength steel. Its bottom is fixed to the ground with expansion bolts to ensure overall stability during mold closing. Several lifting hydraulic rods 4 are arranged between the inner side of the grounding frame 3 and the upper casting module 1. The cylinder diameter of the hydraulic rods is selected from... With a diameter of 80-120mm and a working pressure of 12-16MPa, the system achieves precise displacement control (positioning accuracy ±0.05mm) through a servo hydraulic system. The opening and closing stroke can be adjusted according to the height requirements of the casting to meet the production needs of products of different specifications.

[0042] The sealing ring 6 below the gating module 5 is made of heat-resistant fluororubber (operating temperature -20~200℃). It is rigidly connected to the external crucible through a flange structure. An O-ring is set on the sealing surface to achieve gas sealing, ensuring stable transmission of pressure (0.2-0.5MPa) inside the crucible. The riser pipe 7 extending into the crucible is made of heat-resistant stainless steel (310S), with an inner diameter of... 15-25mm, with the bottom end 100-150mm from the bottom of the crucible to avoid sucking in oxide slag from the bottom of the crucible. Its outer wall and the gating module 5 are dynamically sealed by a graphite sealing sleeve 11 to ensure that the molten metal rises smoothly along the riser pipe 7 under pressure and fills the cavity.

[0043] The gating module 5 is internally equipped with a gating connector 8, which includes a gating pipe 801 connecting the casting lower module 2 and the gating module 5. The gating pipe 801 is a corrugated pipe, with its lower half being a gating spiral section 8011 and its upper half being a gating straight pipe section 8012. The ends of the gating spiral section 8011 and the gating straight pipe section 8012 are respectively located at the gating connection points between the casting lower module 2 and the gating module 5. The spiral section 8011 is spiral in shape. The runner pipe 801 is made of shape memory alloy. The phase change temperature of the runner pipe 801 is set at 680-720℃, which is slightly higher than the upper limit of the normal working temperature of the mold. The ends of the spiral section 8011 and the straight section 8012 are corrugated. The straight section 8012 has a protrusion 802 on its outer periphery. The straight section 8012 has a positioning plate 803 fixed to the top of the runner module 5 on its outer periphery.

[0044] Working principle: During the mold assembly stage, the sprue pipe 801 (made of shape memory alloy) is first pretreated by heating it to a phase transformation temperature above 680-720℃. At this time, the sprue spiral section 8011 and the sprue straight pipe section 8012 deform, and the inner diameter shrinks to slightly smaller than the preset inner diameter of the runner. Then, the pipe is inserted into the runner connection between the casting lower module 2 and the sprue module 5. After cooling, the pipe returns to the preset shape, and its corrugated end fits tightly against the inner wall of the runner. The spiral sprue spiral section 8011 eliminates the small steps caused by processing errors or assembly gaps due to its flexibility, so that the inner diameter of the runner remains consistent and the flow resistance of the molten metal is reduced.

[0045] During the low-pressure casting process, the molten metal rises along the riser pipe 7 under the pressure inside the crucible and enters the gating pipe 801 through the gating module 5. When the molten metal flows through the spiral section 8011 of the gating, the spiral structure absorbs the impact kinetic energy of the molten metal through its own elastic deformation, slows down the flow rate fluctuation, and avoids defects such as cold shut or incomplete filling caused by local turbulence. At the same time, the shape memory alloy maintains a stable shape at the working temperature of the mold (below the phase transformation temperature), and its corrugated end fits tightly with the flow channel to ensure that the molten metal does not leak. The protrusion 802 on the outer periphery of the straight pipe section 8012 of the gating cooperates with the positioning pressure plate 803 to further restrict the axial displacement of the pipe and ensure the long-term stability of the flow channel connection.

[0046] After the casting is formed, as the mold temperature decreases, the sprue fitting 801 can still maintain its fit with the runner, which facilitates subsequent mold opening and part removal. If replacement or maintenance is required, the fitting can be deformed and detached from the runner by reheating, which is convenient. This design not only optimizes the flowability of the molten metal by eliminating the runner steps, but also extends the service life of the runner by using the buffering effect of the spiral structure, thereby improving the forming quality of complex structure castings and the durability of the mold.

[0047] The fluctuation or vibration of the aforementioned gating pipe 801 will generate tensile force, which may affect the sealing performance between the gating module 5 and the sealing connection ring 6. To address this, the following structure is designed.

[0048] A sealing ring 9 is connected to the bottom of the gating module 5 and the top of the sealing connecting ring 6. A ring shell 10 is provided on the outer periphery of the sealing ring 9. A sealing sleeve 11 is provided on the inner side wall of the ring shell 10. The sealing sleeve 11 is made of elastic metal material and has a rubber layer on the inner side. A pressure ring 12 is connected to the top of the sealing sleeve 11. The pressure ring 12 and the top of the sealing sleeve 11 are attached to each other to form a constraint and positioning effect. A compression member 13 is provided between the straight pipe section 8012 of the gating and the ring shell 10.

[0049] The compression component 13 includes a spring slide plate 131 connected to the straight pipe section 8012 of the gating system. The spring slide plate 131 slides and limits the gating module 5. Multiple connecting plates 132 are connected to the top of the spring slide plate 131. The connecting plates 132 pass through the gating module 5 and can move and limit the movement of the gating module 5 in the vertical direction. A spring slide outer ring 133 is connected between the outer peripheries of the multiple connecting plates 132. The spring slide outer ring 133 has a C-shaped cross section. A stacked spring sheet 134 with an overall ring shape is provided between the spring slide outer ring 133 and the compression ring 12. The stacked spring sheet 134 has a multi-wave structure. The crest of the stacked spring sheet 134 fits against one side of the sealing sleeve 11. The stacked spring sheet 134 is made of elastic metal.

[0050] Working principle: During the low-pressure casting process, when the molten metal flows through the gating pipe 801, the spiral section 8011 of the gating will experience periodic fluctuations or vibrations due to the impact of the molten metal. This dynamic force is transmitted to the spring slide 131 of the compaction component 13 through the straight pipe section 8012 of the gating. The spring slide 131 slides along the gating module 5, which drives the connecting plate 132 at the top to move vertically, thereby pulling the outer ring 133 (C-shaped section) up and down.

[0051] When the outer ring 133 moves upward, it compresses the overlapping spring 134 (multiple wave-shaped elastic metal structure). The wave-shaped structure contracts and deforms, and the crest of the wave forms a radial thrust on the sealing sleeve 11. The sealing sleeve 11 is made of elastic metal material with a rubber layer attached to the inside. After being compressed, it deforms inward and tightly wraps the outer periphery of the sealing ring 9, completely pressing and sealing the gap between the upper and lower sealing rings 9, eliminating the risk of gap leakage.

[0052] When the vibration of the gating pipe 801 weakens or resets, the stacked spring 134 returns to its original shape due to its elasticity, driving the outer ring 133 and the slide plate 131 back to their original positions. However, the sealing sleeve 11 still maintains the contact pressure on the sealing ring 9 to maintain the basic sealing effect. This "fluctuation-extrusion-sealing" linkage, which utilizes the dynamic force caused by the flow of molten metal, can automatically enhance the sealing performance during the casting process without the need for an additional power source, ensuring stable pressure transmission in the crucible, preventing molten metal leakage or gas infiltration, and improving the reliability of low-pressure casting.

[0053] Relying solely on ordinary rubber layers for sealing results in a weak sealing effect. To address this, the rubber layer is improved.

[0054] An expansion member 14 is also provided inside the sealing sleeve 11. The expansion member 14 consists of an expansion protrusion 141 and an inner recess 142. The expansion protrusion 141 is two camel-hump shapes protruding inward. The expansion protrusion 141 is made of shape memory polymer or piezoelectric material, etc. The inner recess 142 is opened on the outer wall of the sealing ring 9.

[0055] Working principle: When the stacked spring sheet 134 generates wave-shaped contraction and expansion due to the vibration of the gating pipe 801, the squeezing force of its crest on the sealing sleeve 11 will be transmitted to the inner expansion member 14. The expansion protrusion 141 (double hump structure) of the expansion member 14 is made of shape memory polymer and piezoelectric material composite.

[0056] Piezoelectric effect triggering: The periodic extrusion of the stacked spring sheet 134 causes mechanical deformation of the piezoelectric material, generating a weak current, which excites the internal molecular chain recombination of the expansion protrusion 141, causing it to expand inward (towards the sealing ring 9).

[0057] Shape memory response: The local heat generated by the extrusion of the stacked spring sheet 134 (heat generated by metal deformation) causes the shape memory polymer to reach the glass transition temperature, restoring the preset "expansion shape". The two camel-hump-shaped protrusions bulge inward and are precisely embedded in the concave opening 142 on the outer wall of the sealing ring 9 to form a physical lock.

[0058] To further enhance sealing performance, additional designs were added to the outer wall of the sealing ring 9 and the inner arc side of the sealing sleeve 11.

[0059] An inner pressure cavity 15 is provided on the outer wall of the sealing ring 9. The inner pressure cavity 15 is composed of a buffer section 151, an inner pressure arc section 152 and an outer pressure section 153. An inner pressure component 16 is provided inside the inner pressure cavity 15. The inner pressure component 16 includes multiple inner pressure arc plates 161. The multiple inner pressure arc plates 161 are distributed in a ring array. One side of the inner pressure arc plate 161 is connected to the outer arc side of the sealing sleeve 11. The inner pressure arc plate 161 is composed of an inner arc body 1611 and a side pressure convex angle 1612. The side pressure convex angle 1612 is located at the top of the inner arc body 1611. The side pressure convex angle 1612 is a convex arc shape and fits with the inner pressure arc section 152.

[0060] Working principle: When the sealing sleeve 11 is squeezed inward by the overlapping spring sheet 134, its outer arc side drives the inner pressure arc plate 161 of the inner pressure member 16 to move inward synchronously. The inner arc body 1611 of the inner pressure arc plate 161 directly acts on the buffer section 151 and the inner pressure arc section 152 of the inner pressure cavity 15. The radial extrusion force of the sealing sleeve 11 is converted into a thrust on the inner side of the sealing ring 9 by the arc structure, which forces the buffer section 151 to undergo elastic deformation. At the same time, it pushes the inner pressure arc section 152 to contract towards the mating surface of the two sealing rings 9, so that the upper and lower sealing rings 9 are closer to each other and the gap is reduced.

[0061] If the central area of ​​the sealing sleeve 11 is concave due to uneven force, the side pressure convex angle 1612 (convex arc shape) of the inner pressure arc plate 161 will make misaligned contact with the inner pressure arc segment 152. At this time, the side pressure convex angle 1612 will rotate slightly outward along the arc surface of the inner pressure arc segment 152. This outward rotation movement generates a lateral component force through the arc surface contact, which continues to act on the inner pressure arc segment 152, forming an additional pressure that causes the two sealing rings 9 to fit together, thus offsetting the weakening of the sealing force caused by the local concavity of the sealing sleeve 11.

[0062] The outer pressure section 153 of the inner pressure cavity 15 serves as an auxiliary support, limiting excessive deformation of the sealing ring 9 and ensuring that the extrusion pressure of the inner pressure component 16 is concentrated on the mating surface. Through the direct thrust of the inner arc body 1611 and the compensating thrust of the side pressure convex angle 1612, a stable pressure can be formed from inside the sealing ring 9 regardless of whether the sealing sleeve 11 is subjected to uniform force. This forces the two sealing rings 9 to fit tightly together, completely blocking the leakage channel and adapting to pressure fluctuations and dynamic sealing requirements during the low-pressure casting process.

[0063] Furthermore, an inner pressure spring block 162 is connected between adjacent inner pressure arc plates 161. The inner pressure spring block 162 and the inner pressure arc plate 161 form a ring. The inner pressure spring block 162 has a structure in which the thickness gradually decreases from both sides to the center. The inner pressure spring block 162 is made of elastic material.

[0064] Working principle: When the sealing sleeve 11 pushes the inner pressure arc plate 161 inward, the gap between the inner pressure arc plates 161 distributed in a ring array gradually narrows, forming a lateral compression on the inner pressure spring block 162 connected between adjacent arc plates. The inner pressure spring block 162 is made of elastic material (such as heat-resistant rubber or elastic metal) and has a wedge-shaped structure with "thickness gradually decreasing from both sides to the center". When compressed, the force points on both sides contract towards the center, forcing the central area to bend and deform (protruding towards the sealing ring 9 contact surface).

[0065] The elastic restoring force generated by this bending deformation is converted into a reverse thrust on the inner pressure arc plates 161 on both sides, pushing the inner pressure arc plates 161 to further compress the inner pressure arc segment 152 of the inner pressure cavity 15. At the same time, the protrusion shape of the spring block itself directly acts on the outer pressure segment 153, forming an additional pressure that causes the two sealing rings 9 to move closer to each other. Even if some inner pressure arc plates 161 are displaced due to uneven force, the elastic deformation of the inner pressure spring block 162 can transmit force through the annular structure to ensure that the pressure on the annular sealing surface is evenly distributed and to avoid local gap leakage.

[0066] The wedge-shaped structure design of the inner pressure spring block 162 can also reduce deformation resistance, enabling it to generate significant thrust under a small amount of extrusion. This, together with the direct extrusion of the inner pressure arc plate 161, forms a "dual drive," significantly improving the tightness of the fit between the two sealing rings 9 and meeting the high sealing requirements under dynamic pressure environments in low-pressure casting.

[0067] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A modular low-pressure casting mold, characterized in that, It includes an upper casting module (1) and a lower casting module (2), with a cavity formed between the upper casting module (1) and the lower casting module (2). A grounding frame (3) is provided on the outer periphery of the upper casting module (1), and a lifting hydraulic rod (4) is connected between the grounding frame (3) and the upper casting module (1). The casting lower module (2) is provided with a gating module (5) at the bottom. A sealing connection ring (6) connected to an external crucible is provided below the gating module (5). The gating module (5) and the grounding frame (3) are partially limited and slidable. A liquid riser pipe (7) extending into the crucible is connected to the bottom of the gating module (5). A gating connector (8) is provided inside the gating module (5). The gating connector (8) includes a gating pipe (801) that connects the casting lower module (2) and the gating module (5) to the gating. The lower half and the upper half of the gating pipe (801) are a gating spiral section (8011) and a gating straight pipe section (8012), respectively. The connection between the gating spiral section (8011) and the gating straight pipe section (8012) is located at the gating connection point of the casting lower module (2) and the gating module (5). The gating spiral section (8011) is spiral in shape. The gating pipe (801) is made of shape memory alloy. The phase transformation temperature of the gating pipe (801) is greater than the working temperature of the mold.

2. The modular low-pressure casting mold according to claim 1, characterized in that, The ends of the spiral section (8011) and the straight pipe section (8012) of the gating system are corrugated. The straight pipe section (8012) of the gating system has a protrusion (802) on its outer periphery. The straight pipe section (8012) of the gating system has a positioning plate (803) fixed to the top of the gating module (5) on its outer periphery.

3. The modular low-pressure casting mold according to claim 1, characterized in that, The bottom of the gating module (5) and the top of the sealing connecting ring (6) are both connected to a sealing ring (9). A ring shell (10) is provided on the outer periphery of the sealing ring (9). A sealing sleeve (11) is provided on the inner side wall of the ring shell (10). The sealing sleeve (11) is made of elastic metal material. A rubber layer is provided on the inner side of the sealing sleeve (11). A pressure ring (12) is connected to the top of the sealing sleeve (11).

4. A modular low-pressure casting mold according to claim 3, characterized in that, A compression member (13) is provided between the straight pipe section (8012) of the gating system and the ring shell (10). The compression member (13) includes a spring slide plate (131) connected to the straight pipe section (8012). The spring slide plate (131) slides in a limited position with the gating module (5). Multiple connecting plates (132) are connected to the top of the spring slide plate (131). The connecting plates (132) penetrate the gating module (5) and can move in a limited position along the vertical direction of the gating module (5). A spring-loaded outer ring (133) is connected between the outer peripheries of the multiple connecting plates (132).

5. A modular low-pressure casting mold according to claim 4, characterized in that, The outer ring (133) has a C-shaped cross section. A stacked spring sheet (134) with an overall ring shape is provided between the outer ring (133) and the pressure ring (12). The stacked spring sheet (134) has a multi-wave structure. The crest of the stacked spring sheet (134) is attached to one side of the sealing sleeve (11). The stacked spring sheet (134) is made of elastic metal.

6. A modular low-pressure casting mold according to claim 5, characterized in that, An expansion member (14) is also provided inside the sealing sleeve (11). The expansion member (14) consists of an expansion protrusion (141) and an inner recess (142). The expansion protrusion (141) is two camel-hump shapes protruding inward. The expansion protrusion (141) is made of shape memory polymer or piezoelectric material. The inner recess (142) is opened on the outer wall of the sealing ring (9).

7. A modular low-pressure casting mold according to claim 5, characterized in that, The outer wall of the sealing ring (9) is provided with an inner pressure cavity (15). The inner pressure cavity (15) is composed of a buffer section (151), an inner pressure arc section (152) and an outer pressure section (153). An inner pressure component (16) is provided inside the inner pressure cavity (15).

8. A modular low-pressure casting mold according to claim 7, characterized in that, The inner pressure component (16) includes multiple inner pressure arc plates (161), which are distributed in a ring array. One side of the inner pressure arc plate (161) is connected to the outer arc side of the sealing sleeve (11).

9. A modular low-pressure casting mold according to claim 8, characterized in that, The inner pressure arc plate (161) is composed of an inner arc body (1611) and a side pressure convex angle (1612). The side pressure convex angle (1612) is located at the top of the inner arc body (1611). The side pressure convex angle (1612) is a convex arc shape and fits against the inner pressure arc segment (152).

10. A modular low-pressure casting mold according to claim 9, characterized in that, An inner pressure spring block (162) is connected between adjacent inner pressure arc plates (161). The inner pressure spring block (162) and the inner pressure arc plate (161) form a ring. The inner pressure spring block (162) has a structure in which the thickness gradually decreases from both sides to the center. The inner pressure spring block (162) is made of elastic material.

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