Exhaust manifold investment casting apparatus based on hierarchical cooling shaping structure

Abstract

The application relates to the technical field of investment casting and discloses an exhaust manifold investment casting equipment based on a hierarchical cooling shaping structure, which comprises a mold group, a main pipe core-pulling module and a branch pipe core-pulling module, the inside of the mold group is provided with a mold cavity, and the inside of the mold group is provided with a cooling pipeline; wherein the main pipe core-pulling module comprises a sliding block one, and the side close to the mold group of the sliding block one is fixedly installed with a core-pulling block. The exhaust manifold investment casting equipment based on the hierarchical cooling shaping structure can effectively solve the problem that, in the prior art, the conventional investment casting wax injection mold usually adopts an integral fixed core-pulling structure, and when the core-pulling is performed on the main pipe end of the exhaust manifold, due to the complex inner cavity curved surface at the intersection of the main pipe and the branch pipe of the exhaust manifold, the diameter of the arc connection at the intersection is greater than the diameter of the outer end of the main pipe, the contact area between the core body of the existing core-pulling structure and the inner wall of the wax mold is large, the friction force is strong, and the inner wall of the wax mold is prone to scratching, pilling and even tearing.

Description

Technical Field

[0001] This invention relates to the field of investment casting technology, and specifically to an investment casting device for an exhaust manifold based on a staged cooling and shaping structure. Background Technology

[0002] Investment casting, also known as lost-wax casting, is a near-net-shape forming process that uses a fusible material (usually wax) to create a model, wraps it with a refractory material to form a shell, melts away the model, and pours in molten metal to obtain high-precision castings with complex shapes. The exhaust manifold is a multi-channel hollow pipe component between the engine cylinder head outlet and the exhaust pipe. It is a core component of the engine's intake and exhaust system, and the forming quality of the inner wall of its wax model is crucial.

[0003] In existing technologies, conventional investment casting wax injection molds mostly adopt an integral fixed core-pulling structure. However, when pulling the core at the main end of the exhaust manifold, there is a complex inner cavity surface at the junction of the main and branch pipes of the exhaust manifold. The diameter of the arc connection at the junction is larger than the outer diameter of the main pipe. The contact area between the core and the inner wall of the wax mold in the existing core-pulling structure is large and the friction is strong, which can easily cause scratches, roughening or even tearing of the inner wall of the wax mold. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides an exhaust manifold investment casting equipment based on a graded cooling and shaping structure. This effectively solves the problem that in existing technologies, conventional investment casting wax injection molds often employ an integral fixed core-pulling structure. However, when pulling the core from the main exhaust manifold end, the complex inner cavity surface at the junction of the main exhaust manifold and branch pipes, with the diameter of the arc connection at the junction being larger than the outer diameter of the main exhaust manifold, results in a large contact area and strong friction between the core and the inner wall of the wax mold in existing core-pulling structures. This easily leads to scratches, roughening, or even tearing of the inner wall of the wax mold.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an exhaust manifold investment casting apparatus based on a staged cooling and shaping structure, comprising: The module includes a main pipe core-pulling module and a branch pipe core-pulling module. The module has an internal cavity and a cooling pipe. The main core-pulling module includes a slider, on which a core-pulling block is fixedly installed. The outer surface of the core-pulling block has an expansion and contraction structure, and the top surface of the core-pulling block is an inclined surface. The expansion and contraction structure includes an inclined block, the inner surface of which slides against the inclined surface. A translation block is slidably connected to the core-pulling block through a receiving groove on its side. A limit rod is fixedly connected to the side wall of the receiving groove, and the outer end of the limit rod extends into the interior of the translation block and is slidably connected thereto. A central rod is slidably connected to the inner circumference of the core-pulling block. A vertical groove communicating with the interior of the receiving groove is opened inside the core-pulling block. A top block fixedly connected to the top of the central rod is slidably connected inside the receiving groove. A shift groove is opened on the inner surface of the inclined block. A support rod that fits against the inner wall of the shift groove is fixedly connected to the outer surface of the top block through the vertical groove. The outer end of the central rod and the interior of the slider are telescopically connected through a transmission structure.

[0006] Furthermore, the branch pipe core-pulling module includes a second slider. A first spinal core-pulling component and a second spinal core-pulling component are fixedly installed on the outer surface of the second slider near the module. A semi-circular block is fixedly connected to the end of the first spinal core-pulling component. A semi-circular groove is opened on the outer surface of the inclined block and the inclined surface. When the inclined block is in the unfolded state, the semi-circular grooves on the outer surface of the inclined block and the inclined surface coincide and can fit against the outer surface of the semi-circular block.

[0007] Furthermore, the inclined surface and the receiving groove are distributed at a 90-degree angle to the axis of the core-pulling block, and there are two inclined surfaces and two receiving grooves symmetrically arranged with the axis of the core-pulling block as the center.

[0008] Furthermore, a tension spring is fitted on the outer circumferential surface of the limiting rod and connected to the side wall surface of the receiving groove, and the outer end of the tension spring is connected to the inner surface of the translation block.

[0009] Furthermore, the interior of the receiving groove is provided with a wedge block one that is fixedly connected to the inner surface of the inclined block, and the inner surface of the translation block is fixedly connected with a wedge block two that fits against the bottom end of the wedge block one.

[0010] Furthermore, the translation block is internally fitted with a first top rod and a second top rod. The inner end of the first top rod passes through the receiving groove and is slidably connected to the inside of the core-pulling block. The receiving groove is internally provided with an adjusting member for adjusting the position of the first top rod and the second top rod. The first top rod is fixedly connected to the second top rod through a connecting arm fixed to its outer surface.

[0011] Furthermore, the adjusting component includes a connecting rod fixedly connected to the lower surface of the support rod, a limiting shaft block is embedded inside the first top rod, and a limiting groove that fits against the outer surface of the limiting shaft block is opened inside the connecting rod. The limiting groove is composed of a vertical section and an inclined section, which are distributed sequentially from top to bottom.

[0012] Furthermore, the first spinal core puller has a positioning groove on its side, and the second spinal core puller has a positioning block fixedly connected to its side. Both the first and second spinal core pullers are composed of multiple movable spinal blocks.

[0013] The technical solution provided by this invention has the following advantages compared with the prior art: 1. In existing technologies, exhaust manifold junction sections often employ fixed core-pulling structures with no radial yielding capability. After the wax mold cools and undergoes radially uniform contraction, it tightly grips the outer wall of the core-pulling section over a large area. Furthermore, the multi-directional contraction stress at the junction of the four-way branch pipes adds to the demolding resistance, making forced removal highly susceptible to defects such as inner wall tearing, scrapping, and adhesion / collapse. This invention, during demolding, first drives the central rod to rise, causing the two inclined blocks on both sides to rise along the inclined surface while tilting and converging towards the center, reducing the distance between the inclined blocks and the inner wall of the wax mold. Subsequently, when the wedge block loses its pressure and restraint, the translation block, under the action of a tension spring, performs a purely horizontal radial contraction motion along the limiting rod. The entire process employs a composite motion of first obliquely rising and yielding, followed by forced horizontal contraction during this process. Both inclined blocks and two translation blocks in the circumferential direction of the core-pulling block can achieve contraction, avoiding the problem of inner wall tearing caused by forced removal.

[0014] 2. This invention features independently zoned cooling pipes within the module, implementing differentiated flow rate and temperature control for the flange thick-walled area, the manifold thick-walled area, and the branch pipe thin-walled area. The thick-walled area experiences slow cooling with a small flow rate, while the thin-walled area experiences rapid cooling with a large flow rate, preventing pipe wall collapse and effectively balancing the solidification rate and shrinkage stress in each area. This significantly reduces the internal stress during wax mold forming and substantially improves the overall dimensional accuracy and structural stability of the four-way manifold exhaust manifold wax mold.

[0015] 3. This invention designs two symmetrically arranged spine-shaped core-pulling components for the four-way branch manifold structure. A near-circular end spine-shaped core-pulling component one and a concave, wrapping end spine-shaped core-pulling component two are nested together, with precise engagement and positioning via positioning grooves and blocks. During mold closing, the two sets of branch core-pulling components can achieve adaptive alignment and tight locking, eliminating splicing misalignment and gap deviation. Simultaneously, the interlocking structure of semi-circular blocks and semi-circular grooves achieves seamless connection between the branch core-pulling and main core core-pulling manifold surfaces, forming a smooth and complete four-way manifold transition surface. This provides greater stability during wax injection, ensuring uniform thickness of the finished product and smooth airflow within the exhaust manifold cavity.

[0016] 4. During the core-pulling and demolding process, the translation block only undergoes pure horizontal shrinkage. When its planar contact area separates from the inner wall of the wax model, it is prone to generating large static friction and instantaneous vacuum adhesion, which can cause the inner wall of the wax model to be scratched or deformed with the displacement of the core-pulling component. To address this, during the shrinkage stage of the translation block, ejector pins one and two remain fully extended and supportive, providing continuous and reliable "point support" for the inner wall of the wax model. This effectively counteracts the adhesive friction generated by the planar shrinkage and prevents the inner wall of the wax model from displacing with the core-pulling component's retraction.

[0017] Simultaneously, the retraction of the ejector pin and the retraction of the inclined block are linked. Before the center pin rises to its limit stroke, the connecting rod drives the limiting groove to move upward, using the inner wall of the inclined section to squeeze the limiting shaft block, driving the ejector pin to retract horizontally, so that the ejector pin completely detaches from the inner wall of the wax mold before the core-pulling block retracts as a whole. This avoids the inner wall of the main pipe being scratched or roughened when ejector pins one and two pull the core. Through adaptive timing control that first supports to prevent sticking and then withdraws to make room, the problem of easy breakage during demolding of parallel confluence cavities without draft angles is solved, improving the yield rate of wax mold molding. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0019] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention; Figure 2 This is a cross-sectional structural diagram of the module, slider one, core pulling block and translation block according to an embodiment of the present invention; Figure 3 This is an embodiment of the present invention. Figure 2 A magnified structural diagram of part A in the middle; Figure 4 This is a schematic diagram of the main pipe core-pulling module and the branch pipe core-pulling module according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the core-pulling block, the inclined block, and the translation block according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the core-pulling block, receiving groove, and semi-circular groove in an embodiment of the present invention; Figure 7 This is a cross-sectional structural diagram of the core-pulling block, the inclined block, and the support rod according to an embodiment of the present invention; Figure 8 This is a cross-sectional structural diagram of the core-pulling block and the inclined block from another angle according to an embodiment of the present invention; Figure 9This is a schematic diagram of the structure of the core rod, top block, support rod, connecting rod, and top rod 1 in an embodiment of the present invention; Figure 10 This is a schematic diagram of the separation structure of spinal core-pulling component one and spinal core-pulling component two according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of the exhaust manifold wax mold product according to an embodiment of the present invention.

[0020] The labels in the diagram represent: 1. Module; 11. Cavity; 12. Cooling pipe; 2. Main core-pulling module; 21. Slider 1; 22. Core-pulling block; 221. Inclined surface; 2211. Semicircular groove; 222. Receiving groove; 223. Vertical groove; 23. Expansion / contraction structure; 231. Inclined block; 2311. Moving groove; 2312. Wedge block 1; 232. Translation block; 2321. Wedge block 2; 233. Limiting rod; 234. Middle 2341. Core rod; 235. Support rod; 236. Tension spring; 24. Top rod one; 241. Top rod two; 25. Adjusting component; 251. Connecting rod; 252. Limiting shaft block; 253. Limiting groove; 2531. Vertical section; 2532. Inclined section; 3. Branch pipe core pulling module; 31. Slider two; 32. Spine core pulling component one; 321. Positioning groove; 33. Spine core pulling component two; 331. Positioning block; 34. Semicircular block. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] The present invention will be further described below with reference to embodiments. Example:

[0023] Please see Figures 1-11 This invention provides a technical solution: an exhaust manifold investment casting device based on a staged cooling and shaping structure, comprising: Module 1, main pipe core pulling module 2 and branch pipe core pulling module 3. Module 1 has a cavity 11 inside and a cooling pipe 12 inside. The main core-pulling module 2 includes a slider 21. A core-pulling block 22 is fixedly installed on the side of the slider 21 near the module 1. The outer surface of the core-pulling block 22 is provided with an expansion and contraction structure 23. The top surface of the core-pulling block 22 is an inclined surface 221. The expansion and contraction structure 23 includes an inclined block 231. The inner surface of the inclined block 231 slides against the inclined surface 221. The core-pulling block 22 is slidably connected to a translation block 232 through a receiving groove 222 on its side. A limit rod 233 is fixedly connected to the side wall of the receiving groove 222. The outer end of the limit rod 233 extends into the interior of the translation block 232 and... The core-pulling block 22 is slidably connected to the inner circumference of the core-pulling block 22, and a vertical groove 223 is opened inside the core-pulling block 22, which is connected to the inside of the receiving groove 222. A top block 2341 is slidably connected inside the receiving groove 222 and fixedly connected to the top of the central rod 234. A sliding groove 2311 is opened on the inner surface of the inclined block 231. The outer surface of the top block 2341 passes through the vertical groove 223 and is fixedly connected to a support rod 235 that fits against the inner wall of the sliding groove 2311. The outer end of the central rod 234 moves in extension and retraction with the transmission structure inside the slider 21.

[0024] The branch pipe core-pulling module 3 includes a second slider 31. A spine core-pulling component 32 and a second spine core-pulling component 33 are fixedly installed on the outer surface of the second slider 31 near the module 1. A semi-circular block 34 is fixedly connected to the end of the first spine core-pulling component 32. A semi-circular groove 2211 is opened on the outer surface of the inclined block 231 and the inclined surface 221. When the inclined block 231 is in the unfolded state, the arc of the semi-circular groove 2211 on the outer surface of the inclined block 231 and the inclined surface 221 coincides and can fit with the outer surface of the semi-circular block 34.

[0025] The inclined surface 221 and the receiving groove 222 are distributed at a 90-degree angle with the axis of the core-pulling block 22. There are two inclined surfaces 221 and two receiving grooves 222, symmetrically arranged with the axis of the core-pulling block 22 as the center.

[0026] A tension spring 236 is fitted on the outer circumference of the limiting rod 233 and is connected to the side wall surface of the receiving groove 222. The outer end of the tension spring 236 is connected to the inner surface of the translation block 232.

[0027] The interior of the receiving groove 222 is provided with a wedge block 2312 fixedly connected to the inner surface of the inclined block 231, and the inner surface of the translation block 232 is fixedly connected with a wedge block 2321 that fits against the bottom end of the wedge block 2312.

[0028] The translation block 232 is internally fitted with a first push rod 24 and a second push rod 241. The inner end of the first push rod 24 passes through the receiving groove 222 and is slidably connected to the inside of the core-pulling block 22. The receiving groove 222 is internally provided with an adjusting member 25 for adjusting the position of the first push rod 24 and the second push rod 241. The first push rod 24 is fixedly connected to the second push rod 241 through a connecting arm fixed to its outer surface.

[0029] The adjusting component 25 includes a connecting rod 251 fixedly connected to the lower surface of the support rod 235. A limiting shaft block 252 is embedded inside the top rod 24. A limiting groove 253 that fits against the outer surface of the limiting shaft block 252 is opened inside the connecting rod 251. The limiting groove 253 is composed of a vertical section 2531 and an inclined section 2532, which are distributed from top to bottom.

[0030] The spinal core puller 32 has a positioning groove 321 on its side, and the spinal core puller 33 has a positioning block 331 fixedly connected to its side. Both the spinal core puller 32 and the spinal core puller 33 are composed of multiple spinal movable blocks.

[0031] Taking a four-way branch pipe integrated exhaust manifold as an example, the spinal core-pulling component 1 32 and spinal core-pulling component 2 33 in the branch pipe core-pulling module 3 are arranged adjacently and symmetrically with the axis of the core-pulling block 22 as the center. Among them, the spinal core-pulling component 1 32 is arranged closer to the core-pulling block 22. The forming output end of the spinal core-pulling component 1 32 adopts a near-circular structure design, while the forming output end of the spinal core-pulling component 2 33 is set as an inwardly concave covering structure, which fits the shape of the end of the spinal core-pulling component 1 32. A positioning groove 321 is opened on the side of the spinal core-pulling component 1 32 near the spinal core-pulling component 2 33, and a positioning block 331 is fixedly assembled on the side of the spinal core-pulling component 2 33 corresponding to the positioning groove 321. When the first spinal core puller 32 and the second spinal core puller 33 extend into the cavity 11 and close the mold, the positioning block 331 can be precisely fitted into the positioning groove 321 along the assembly path, realizing the adaptive alignment and limiting fit of the first spinal core puller 32 and the second spinal core puller 33. The two fit together to form the four-branch confluence transition molding surface. The parting surface of module 1 adopts a right-angled large arc transition structure that is completely fitted with the arc contour of the branch pipe, matching the irregular bending trajectory of the branch pipe, effectively optimizing the mold opening and closing alignment accuracy, and eliminating the misalignment gap of the parting surface.

[0032] Module 1 is initially in the mold-closed state: After the equipment is molded, module 1, main pipe core-pulling module 2, and branch pipe core-pulling module 3 are fully aligned and locked, and the overall structure is in a ready-to-form state. At this time, the center rod 234 is in its shortest contracted state inside the core-pulling block 22, the expansion and contraction structure 23 on the outer surface of the core-pulling block 22 is fully in the expanded working state, the distance between the two inclined blocks 231 is at the maximum stroke position, and the two translation blocks 232 also maintain the maximum expansion distance within their own sliding stroke range, thereby matching the standard inner cavity size of the exhaust manifold.

[0033] In this state, the top block 2341 is located at the bottom of the vertical groove 223, and the support rod 235 and connecting rod 251 are simultaneously at their lowest stroke positions. The outer surface of the limiting shaft block 252 is in contact with the inner wall of the vertical section 2531 inside the limiting groove 253, keeping the top rod 24 and the second top rod 241 in an extended and unfolded state. Within their own stroke range, the top rods 24 and 241 are at their outermost extreme positions close to the outer surface of the core-pulling block 22, and the outer surfaces of the top rods 24 and 241 are flush with the outer surface of the core-pulling block 22, sharing the inner curved surface of the exhaust manifold main pipe.

[0034] In this initial state, the spinal core-pulling component 32 and spinal core-pulling component 33 in the branch core-pulling module 3 are precisely fitted and aligned with the core-pulling block 22, inclined block 231, and translation block 232 in the main core-pulling module 2. The outer surfaces of each structure are spliced ​​together to form a complete exhaust manifold multi-channel confluence inner wall forming surface. Specifically, the outer surface of the core-pulling block 22 forms the base shape of the main pipe inner wall, the outer surfaces of the inclined block 231 and translation block 232 form the curved surface part of the main pipe inner wall, the outer surfaces of the spinal core-pulling component 32 and spinal core-pulling component 33 form the shape of the branch pipe inner wall, the semi-circular block 34 is embedded in the semi-circular groove 2211, and the outer surfaces of the spinal core-pulling component 32, spinal core-pulling component 33, inclined block 231, and core-pulling block 22 together form the inner wall curved surface at the junction of the main pipe and the branch pipe. The outer surfaces of each component are seamlessly connected, together forming a complete exhaust manifold inner cavity shape, ready for wax injection.

[0035] In the initial state, the bottom end of wedge block 1 2312 presses tightly against the upper surface of wedge block 2321, causing the distance between the two translation blocks 232 to be maximized. The tension spring 236 sleeved on the outside of the limiting rod 233 is in a forced tension state, ensuring that the overall expansion and contraction structure 23 is stable in its forming state and will not loosen or misalign.

[0036] The process of wax injection molding and graded cooling and setting: After the initial alignment is completed, the equipment starts the wax injection process. Molten wax is injected into the cavity 11 of module 1. The wax completely covers the inner surface of the outer cavity 11 and the outer surfaces of the inner core-pulling block 22, inclined block 231, translation block 232, spine core-pulling component 1 32, and spine core-pulling component 2 33. After filling, pressure is maintained and the shape is set. During the molding and pressure holding stage, the cooling pipes 12 inside module 1 activate a graded gradient cooling logic, controlling the temperature in zones according to the structural characteristics of the exhaust manifold. The thick-walled areas of the flange and the thick-walled areas of the manifold employ a low-flow, slow cooling mode to ensure slow solidification and sufficient shrinkage compensation, avoiding shrinkage pits and depressions. The thin-walled areas of the branch pipes employ a high-flow, fast cooling mode to quickly solidify the thin-walled areas, preventing the hollow pipe walls from collapsing or deforming under their own weight. This graded cooling method solves the technical pain points of traditional molds where the entire mold is cooled synchronously, but the solidification of thick and thin walls is asynchronous. It reduces the probability of wax mold warping, manifold deformation, and branch pipe misalignment, ensuring the overall dimensional accuracy and structural stability of the wax mold. After the wax mold has completely cooled and solidified and its structural strength meets the requirements, the equipment initiates the sequential core-pulling and demolding process. The process of removing the branch pipe core and demolding: In the initial demolding stage, the external drive mechanism first moves the second slider 31, which in turn drives the first and second spine core-pulling parts 32 and 33 to exit from inside the module 1, i.e., to be pulled outward along the extension direction of the branch tube. Since the first and second spine core-pulling parts 32 and 33 are both composed of multiple spine movable blocks, each spine movable block can independently and finely adjust its position according to the curved shape of the inner wall of the branch tube during the extraction process, reducing the friction and contact area with the inner wall of the wax model, and preventing the inner wall of the branch tube from being scratched or roughened during core pulling.

[0037] After the spine core-pulling component 1 32 and spine core-pulling component 2 33 are completely withdrawn, the semi-circular block 34 also comes out of the semi-circular groove 2211. The separation of the semi-circular block 34 from the semi-circular groove 2211 means that the spine core-pulling component 1 32, spine core-pulling component 2 33, and core-pulling block 22 are no longer mutually constrained and interlocked, creating conditions for the subsequent staged shrinkage demolding of the main core-pulling module 2.

[0038] The process of demolding the main shaft: After the branch tube core is fully retracted, the internal transmission structure of slider 21 is activated, driving the central rod 234 to move upward. The central rod 234 drives the top block 2341 and the support rod 235, which are fixed at the top, to rise vertically simultaneously. The support rod 235 slides along the inner wall of the sliding groove 2311 inside the inclined block 231, while the inner surface of the inclined block 231 slides along the inclined surface 221 on the top surface of the core-pulling block 22. This causes the two inclined blocks 231 to rise vertically simultaneously and converge towards the center, gradually reducing the distance between the two inclined blocks 231. This achieves a combined motion of inclined blocks 231 tilting upward and radially contracting. During the upward movement, the distance between the outer surface of the inclined block 231 and the inner wall of the wax model gradually increases, achieving the gradual separation of the inclined block 231 from the inner wall of the wax model.

[0039] When the inclined block 231 rises to the preset stroke, the wedge block 2312 at the bottom of the inclined block 231 moves upward synchronously, and the bottom end of the wedge block 2312 loses its pressure and limiting effect on the upper surface of the wedge block 2321. At this time, the translation block 232 and the wedge block 2321 are no longer rigidly limited, and under the elastic recoil force of the tension spring 236, they slide horizontally inward along the axis of the limiting rod 233. The distance between the two translation blocks 232 decreases synchronously, realizing a pure horizontal radial contraction and yielding.

[0040] It is worth noting that, in order to ensure the integrity of the top of the core-pulling block 22 at the pipe junction, the translation block 232 only performs a purely horizontal retraction movement within the receiving groove 222. A cavity is provided on the inner surface of the translation block 232 for sliding with the limiting rod 233. There is no tilting or yielding structure. After retraction, it can detach from the inner wall contact surface of the wax mold, but there is still a significant risk of static friction and adhesion in the planar contact area. Therefore, when the translation block 232 horizontally retracts and detaches from the inner wall of the wax mold, the ejector rods 241 and 242 remain fully extended and supportive. The outer ends of the ejector rods 241 and 242 continuously maintain supportive contact with the inner wall of the wax mold confluence. After the translation block 232 retracts, it provides continuous and reliable point support for the inner wall of the wax mold, ensuring the shape stability of the wax mold during the core-pulling process. This forms a fixed-point support and anti-detachment limit for the inner wall of the wax mold, effectively offsetting the adhesive friction generated by the planar retraction, and preventing the inner wall of the wax mold from being strained, adhered, or deformed due to the core-pulling displacement. The number and distribution of the push rods 241 are designed according to the shape of the inner wall of the wax mold and the stress conditions to ensure the uniformity and reliability of the support.

[0041] When the center rod 234 lifts, causing the top block 2341 and the support rod 235 to rise to their maximum limit stroke, the inclined block 231, under the action of its internal sliding groove 2311, also rises to its maximum limit stroke. The distance between the outermost endpoints of the two inclined blocks 231 reaches its minimum state. At this time, the distance between the outermost endpoints of the two inclined blocks 231 is less than the outer diameter of the core-pulling block 22, thus achieving complete radial retraction. The inclined block 231 is guided by the slide rail on the inclined surface 221 throughout its entire stroke, tilting and retracting towards the center while rising, while the translation block 232 only retracts horizontally.

[0042] The process of adjusting component 25 retracting push rod 1 24 and push rod 241: As the center rod 234, top block 2341, and support rod 235 are about to reach their highest stroke position, the connecting rod 251 fixed at the bottom of the support rod 235 moves upward synchronously, and the limiting groove 253 inside the connecting rod 251 moves vertically in sync. The limiting groove 253 consists of an upper vertical section 2531 and a lower inclined section 2532. As the whole structure moves upward, the contact position between the limiting shaft block 252 and the limiting groove 253 gradually changes from the vertical section 2531 to the inclined section 2532.

[0043] Among them, the inclined section 2532 is inclined from top to bottom toward the axis of the core-pulling block 22. Therefore, during the contact switching process, the inner wall of the limiting groove 253 squeezes the limiting shaft block 252, which drives the first push rod 24 to move horizontally toward the center line of the core-pulling block 22. Meanwhile, several second push rods 241 are fixedly connected to the first push rod 24 through the connecting arm and move horizontally toward the center line of the core-pulling block 22 in sync, so that the first push rod 24 and the second push rod 241 switch from the outer support state to the inner contraction state.

[0044] After shrinkage, the distance from the center line of the core-pulling block 22 to the outer surface of ejector pin 1 24 and ejector pin 241 is less than the distance from the center line of the core-pulling block 22 to the inner wall of the wax mold. This allows all ejector pin structures to completely detach from the contact surface of the inner wall of the wax mold, completely releasing the support limit and providing sufficient clearance for subsequent overall core-pulling retraction. There is no contact or scratching throughout the process, completely avoiding scratching or tearing the inner wall of the wax mold during core-pulling retraction, and achieving non-destructive demolding of the converging hollow inner cavity.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. An exhaust manifold investment casting device based on a staged cooling and shaping structure, characterized in that, include: The module (1), the main pipe core-pulling module (2) and the branch pipe core-pulling module (3) are provided. The module (1) has a cavity (11) inside and a cooling pipe (12) inside. The main core-pulling module (2) includes a slider (21), on which a core-pulling block (22) is fixedly installed. The outer surface of the core-pulling block (22) is provided with an expansion and contraction structure (23). The top surface of the core-pulling block (22) is an inclined surface (221). The expansion and contraction structure (23) includes an inclined block (231). The inner surface of the inclined block (231) slides against the inclined surface (221). The core-pulling block (22) is slidably connected to a translation block (232) through a receiving groove (222) on its side. A limit rod (233) is fixedly connected to the side wall of the receiving groove (222). The outer end of the rod (233) extends into the interior of the translation block (232) and is slidably connected thereto. The inner circumferential surface of the core-pulling block (22) is slidably connected to the central rod (234). The interior of the core-pulling block (22) is provided with a vertical groove (223) that communicates with the interior of the receiving groove (222). The interior of the receiving groove (222) is slidably connected to a top block (2341) that is fixedly connected to the top of the central rod (234). The inner surface of the inclined block (231) is provided with a shift groove (2311). The outer surface of the top block (2341) penetrates the vertical groove (223) and is fixedly connected to a support rod (235) that fits against the inner wall of the shift groove (2311).

2. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 1, characterized in that: The branch core-pulling module (3) includes a second slider (31). The outer surface of the second slider (31) near the module (1) is fixedly installed with a first spinal core-pulling component (32) and a second spinal core-pulling component (33). The end of the first spinal core-pulling component (32) is fixedly connected with a semi-circular block (34). The outer surface of the inclined block (231) and the inclined surface (221) is provided with a semi-circular groove (2211).

3. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 1, characterized in that: The inclined surface (221) and the receiving groove (222) are distributed at a 90-degree angle with the axis of the core-pulling block (22). The inclined surface (221) and the receiving groove (222) are symmetrically arranged with the axis of the core-pulling block (22) as the center.

4. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 3, characterized in that: The outer circumferential surface of the limiting rod (233) is fitted with a tension spring (236) that is connected to the side wall surface of the receiving groove (222), and the outer end of the tension spring (236) is connected to the inner surface of the translation block (232).

5. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 4, characterized in that: The receiving groove (222) is provided with a wedge block one (2312) fixedly connected to the inner surface of the inclined block (231), and the translation block (232) is fixedly connected with a wedge block two (2321) that fits against the bottom end of the wedge block one (2312).

6. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 5, characterized in that: The translation block (232) is internally fitted with a first top rod (24) and a second top rod (241). The inner end of the first top rod (24) passes through the receiving groove (222) and is slidably connected to the inside of the core-pulling block (22). The receiving groove (222) is internally provided with an adjusting member (25) for adjusting the position of the first top rod (24) and the second top rod (241). The first top rod (24) is fixedly connected to the second top rod (241) through a connecting arm fixed on its outer surface.

7. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 6, characterized in that: The adjusting component (25) includes a connecting rod (251) fixedly connected to the lower surface of the support rod (235). A limiting shaft block (252) is embedded inside the top rod (24). A limiting groove (253) that fits against the outer surface of the limiting shaft block (252) is opened inside the connecting rod (251). The limiting groove (253) is composed of a vertical section (2531) and an inclined section (2532). The vertical section (2531) and the inclined section (2532) are distributed from top to bottom.

8. The exhaust manifold investment casting equipment based on a staged cooling and shaping structure according to claim 2, characterized in that: The first spinal core extractor (32) has a positioning groove (321) on its side, and the second spinal core extractor (33) has a positioning block (331) fixedly connected to its side.

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