A multi-directional core-pulling engine cylinder head low pressure casting mold

Abstract

The application discloses a multi-direction core-pulling engine cylinder cover low-pressure casting mold and relates to the technical field of metal casting, aiming to solve the technical problem of defects in the demolding of the cylinder cover mold, comprising a core-pulling mechanism and a mold core mechanism meshing transmission, a mold forming part composed of multiple segments and magnetic separation parts embedded between the segments, an air inlet unit and a ventilation groove group provided on the mold forming part. The core-pulling mechanism is meshed and transmitted with the rotating part, synchronous and stable driving of the core-pulling is realized, and the core-pulling path precision is ensured. The mold forming part with multiple segments and the magnetic separation part are controlled by magnetic force on-off, the segment axial attraction and circumferential positioning are realized during mold clamping, the magnetic force is disconnected to generate a small gap to release the wrapping force during mold demolding, and mold sticking and damage are avoided. The air inlet unit and the ventilation groove group are designed in an integrated manner, micro-pores exude gas to form a micro-air cushion to realize forced exhaust during mold filling, and the same air path forms auxiliary lubrication at the gap during mold demolding. A set of air paths realizes the double effects of exhaust anti-sticking and lubrication drag reduction, and the casting quality and mold demolding reliability are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of metal casting technology, and more specifically, to a low-pressure casting mold for engine cylinder heads with multi-directional core pulling. Background Technology

[0002] With the continuous development of automotive lightweighting technology, the use of high-strength, lightweight die-cast aluminum alloys to manufacture engine cylinder heads has become an industry trend. This material can significantly reduce engine weight while ensuring mechanical properties, which is of great significance for improving fuel economy.

[0003] However, the split cylinder head consists of a top plate, a cylinder head body, and a bottom plate. The top plate integrates cooling channels, which have an asymmetrical structure. Due to the asymmetry and complexity of the engine cylinder head top plate structure, it presents significant challenges in low-pressure casting, primarily during the demolding process. For example, the asymmetrically distributed cooling channels can easily generate unbalanced clamping forces during demolding, and the deep cavity structure is highly prone to sticking defects. Therefore, precise coordination of multi-directional core pulling is required.

[0004] Traditional low-pressure casting molds typically employ simple vertical or horizontal parting methods, coupled with limited core-pulling mechanisms, making it difficult to handle the demolding requirements of curved water channels. Traditional demolding methods have significant drawbacks; various factors such as uneven application of release agent, asynchronous core-pulling movements, or uneven temperature distribution in the mold can lead to localized adhesion between the casting and the cavity surface. This can result in minor issues like surface scratches and dimensional errors, or even jamming of the core-pulling mechanism and mold damage, severely impacting production efficiency and yield.

[0005] Therefore, designing a low-pressure casting mold capable of smooth multi-angle demolding for complex structural components such as engine cylinder head top plates, and overcoming demolding defects caused by mold release agent failure, motion interference, or uneven thermal stress in existing technologies, has become a pressing technical problem for those skilled in the art. In light of this, we propose a multi-directional core-pulling low-pressure casting mold for engine cylinder heads. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-directional core-pulling low-pressure casting mold for engine cylinder heads, so as to solve the technical problem that existing cylinder head molds are prone to defects during demolding.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a multi-directional core-pulling low-pressure casting mold for engine cylinder heads, comprising an upper mold base and a lower mold base, wherein the upper mold base is provided with a top plate mold, the lower mold base is provided with a top plate lower mold, a core-pulling mechanism is symmetrically arranged on the lower mold base, a core mechanism is provided inside the lower mold base, the core mechanism is meshed with the core-pulling mechanism, and the output end of the core mechanism is movably inserted into the top plate lower mold; the core mechanism includes a rotating part, a forming part, a magnetic ionization part, an air intake unit, and a ventilation groove assembly; the forming part is composed of multiple segments; The rotating part is rotatably disposed within the lower mold base and engages with the core-pulling mechanism. It is used to rotate under the drive of the core-pulling mechanism and drive the air intake unit and the molding part to move, so as to insert or withdraw from the lower mold of the top plate. The air intake unit is fixedly connected to the end of the rotating part away from the lower mold base. The molding part is sleeved on the air intake unit. The magnetic separation part is embedded between the segments of the molding part and is used to disconnect the magnetic force during demolding, so as to create tiny gaps between the segments to facilitate demolding. The ventilation groove group is opened on the air intake unit and the molding part for ventilation during casting.

[0008] Preferably, the core-pulling mechanism includes a mounting frame, a cylinder, a clamping plate, and a plate rack. The mounting frame is symmetrically fixed on the lower mold base, the cylinder is disposed on the mounting frame, the clamping plate is fixedly connected to the output end of the cylinder, the plate rack is fixedly connected to the clamping plate, and the plate rack is meshed with the rotating part.

[0009] Preferably, the rotating part includes a main shaft, a central gear, a driven gear, and a rotating block. The main shaft is rotatably disposed within the lower mold base. The central gear is fixedly sleeved in the middle of the main shaft and meshes with the plate rack. The driven gear is fixedly sleeved at one end of the main shaft and meshes with the rotating block.

[0010] Preferably, the rotating block has a rotating hole, and the rotating block is rotatably sleeved on the sliding shaft through the rotating hole. The sliding shaft is located inside the lower mold base.

[0011] Preferably, the rotating block is further provided with an arc rack, which meshes with the driven gear.

[0012] Preferably, the molding part includes a core segment, a mounting groove and a through groove, a plurality of the core segments are movably sleeved on the air intake unit through the through groove, the mounting groove is opened at both ends of the core segment, the magnetic ionization part is provided on the mounting groove, and the ventilation groove group is opened on the core segment.

[0013] Preferably, the magnetic separation part includes a magnetic ring, which is embedded in the opposite end faces of adjacent segments of the molding part; magnetic sheets are arranged in a ring at equal intervals inside the magnetic ring, so that when the mold is closed, the magnetic rings on adjacent segments attract each other through opposite magnetic poles, so that each segment of the molding part is positioned to a preset angle in the circumferential direction.

[0014] Preferably, the magnetic ring is an electromagnet, and the magnetic ionization part further includes a conductive slip ring embedded in the lower mold base, the conductive slip ring being electrically connected to the magnetic ring; The conductive slip ring is used to connect to an external power source. When the mold is closed, the power is applied to the magnetic ring to generate magnetic force to attract adjacent segments. When the mold is demolded, the power is cut off to make the magnetic force disappear.

[0015] Preferably, the air intake unit includes an air passage, an end block, an air intake tube, and an end block. The air passage is opened on the rotating part, the end block is fixedly disposed on the rotating part, the air intake tube is fixedly disposed at the end of the end block away from the rotating part, the end block is disposed at the end of the air intake tube away from the end block, and the molding part is movably sleeved on the air intake tube.

[0016] Preferably, the ventilation slot assembly includes air outlets and air curtain holes. A plurality of air outlets are arranged in a ring at equal intervals on the air inlet tube, and the air curtain holes are arranged in a ring at equal intervals on the molding part. The air passage, the air inlet tube, the air outlets and the air curtain holes are connected.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes the meshing transmission between the core-pulling mechanism and the rotating part of the core-forming mechanism to convert the linear motion of the cylinder into the oscillating motion of the rotating block through multiple stages including a plate rack, central gear, main shaft, driven gear, and arc rack. This, in turn, drives the mold-forming part to move precisely along the bending axis. This transmission mechanism not only achieves synchronous and smooth driving for bidirectional symmetrical bending core pulling, solving the jamming problem caused by uneven force when using traditional inclined guide pillars or direct cylinder pulling, but also ensures the repeatability of the core-pulling path through the high-precision characteristics of gear meshing, significantly improving mold life and core-pulling reliability.

[0018] 2. This invention designs the molding section as a multi-core segment combination structure and embeds magnetic separation parts between adjacent segments. Through the attraction of opposite polarities of the annular equally spaced magnetic sheets inside the magnetic ring, the dual functions of axial tight fit and circumferential precise positioning of each segment are achieved during mold closing, avoiding segment misalignment caused by uneven force during bending core pulling. During demolding, the magnetic force disconnects the segments, creating tiny gaps between them, effectively releasing the unbalanced clamping force between the inner and outer arc sides of the bent cavity, and introducing gas lubrication, fundamentally solving the technical problems of high demolding resistance and easy damage to the inner surface of the casting during bending core pulling.

[0019] 3. This invention integrates the air intake unit with the ventilation channel assembly, forming a built-in exhaust and lubrication channel through air passages, intake pipes, exhaust holes, and air curtain holes. During the filling stage, micro-air cushions are formed by gas seepage through micropores, achieving forced exhaust at the bottom of the curved cavity and isolating the molten metal from direct contact with the mold, thus solving the problem of air entrapment and porosity defects at bends. During the demolding stage, the same air path forms an auxiliary lubricating air film at the pores created by segment separation, further reducing demolding resistance. This design achieves the dual technical effects of venting and preventing sticking during filling and lubrication and resistance reduction during demolding with a single air path system, significantly improving casting quality and demolding smoothness. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the engine cylinder head top plate structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the overall structure of the mold of the present invention.

[0022] Figure 3 This is a schematic diagram of the disassembled upper and lower mold bases of the present invention.

[0023] Figure 4 This is a schematic diagram of the cross-sectional structure of the upper and lower mold bases of the present invention.

[0024] Figure 5 This is a schematic diagram of the core-pulling mechanism and rotating part of the present invention.

[0025] Figure 6 This is a schematic diagram of the meshing structure between the plate rack and the central gear of the main shaft according to the present invention.

[0026] Figure 7 This is a schematic diagram of the core mechanism and plate rack structure of the present invention.

[0027] Figure 8 This is a schematic diagram of the rotating part and the molding part of the present invention.

[0028] Figure 9 This is a schematic cross-sectional view of the rotating block and intake manifold of the present invention.

[0029] Figure 10 This is a schematic diagram of the internal structure of the core segment of the present invention.

[0030] Figure 11 This is a schematic diagram of the cross-sectional structure of the core segment of the present invention.

[0031] Figure 12 This is a front view structural diagram of the core segment and intake manifold of the present invention.

[0032] Explanation of the labels in the diagram: 1. Upper mold base; 2. Lower mold base; 3. Mold on top plate; 4. Lower mold on top plate; 5. Core pulling mechanism; 6. Core mechanism; 501. Mounting bracket; 502. Cylinder; 503. Clamping plate; 504. Plate rack; 601. Rotating part; 602. Molding part; 603. Magnetic ionization part; 604. Air intake unit; 605. Ventilation slot assembly; 6011, Main spindle; 6012, Center gear; 6013, Driven gear; 6014, Rotary block; 6015, Rotary hole; 6016, Sliding shaft; 6017, Arcuate rack; 6021, Core segment; 6022, Mounting slot; 6023, Through slot; 6031, magnetic ring; 6041, airway; 6042, end piece; 6043, intake manifold; 6044, end piece; 6051, Vent; 6052, Air curtain hole. Detailed Implementation

[0033] like Figures 1 to 12 As shown, the present invention relates to a multi-directional core-pulling low-pressure casting mold for engine cylinder heads, comprising an upper mold base 1 and a lower mold base 2. The upper mold base 1 is provided with a top plate mold 3, and the lower mold base 2 is provided with a top plate lower mold 4. A core-pulling mechanism 5 is symmetrically arranged on the lower mold base 2, and a core mechanism 6 is provided inside the lower mold base 2. The core mechanism 6 is meshed with the core-pulling mechanism 5, and the output end of the core mechanism 6 is movably inserted into the top plate lower mold 4. The core mechanism 6 includes a rotating part 601, a forming part 602, a magnetic ionization part 603, an air intake unit 604, and a ventilation slot assembly 605. The forming part 602 is composed of multiple segments; the rotating part 601... 1. Rotatably mounted inside the lower mold base 2 and engaged with the core-pulling mechanism 5, it is used to rotate under the drive of the core-pulling mechanism 5, and drive the air intake unit 604 and the mold forming part 602 to move, so as to insert or withdraw the lower mold 4 of the top plate; the air intake unit 604 is fixedly connected to the end of the rotating part 601 away from the lower mold base 2; the mold forming part 602 is sleeved on the air intake unit 604; the magnetic separation part 603 is embedded between the segments of the mold forming part 602, and is used to disconnect the magnetic force during demolding, so as to create tiny gaps between the segments to facilitate demolding; the ventilation groove group 605 is opened on the air intake unit 604 and the mold forming part 602 for ventilation during casting.

[0034] In this invention, the core-pulling mechanism 5 drives the rotating part 601 meshing with it to rotate. The rotating part 601 drives the air intake unit 604 fixedly connected to it and the forming part 602 sleeved on the air intake unit 604 to move along the bending axis, so that the forming part 602 inserts into or exits the mold 4 under the top plate. In the mold-closed state, the magnetic separation part 603 embedded between the multiple segments of the forming part 602 maintains magnetic attraction, so that each segment fits tightly to form a complete bending cavity. During the casting process, ventilation is carried out through the ventilation groove group 605 opened on the air intake unit 604 and the forming part 602. When demolding, the magnetic force of the magnetic separation part 603 is disconnected, so that a small gap is generated between each segment, thereby releasing the complex frictional resistance caused by uneven contact pressure distribution during the bending core-pulling process, which makes it easy for the forming part 602 to smoothly exit from the bending channel of the casting. This invention achieves smooth driving of bidirectional symmetrical curved tube core pulling through the meshing transmission of the core pulling mechanism 5 and the core mechanism 6; through the magnetic force on / off control of the magnetic separation part 603, micro-pores are actively generated during demolding, which effectively solves the problems of jamming, wear and tear caused by uneven friction between the inner and outer arc sides during the core pulling process of curved tubes, and significantly improves the forming quality and demolding reliability of complex curved channels.

[0035] In an embodiment of the present invention, the core-pulling mechanism 5 includes a mounting frame 501, a cylinder 502, a clamping plate 503, and a plate rack 504. The mounting frame 501 is symmetrically fixed on the lower mold base 2, the cylinder 502 is disposed on the mounting frame 501, the clamping plate 503 is fixedly connected to the output end of the cylinder 502, the plate rack 504 is fixedly connected to the clamping plate 503, and the plate rack 504 is meshed with the rotating part 601.

[0036] In this invention, cylinder 502 drives clamping plate 503 to move linearly, and clamping plate 503 drives rack 504 fixedly connected to it to move synchronously. Rack 504 meshes with rotating part 601, thereby accurately converting the linear motion of cylinder 502 into the rotational motion of rotating part 601. The use of rack 504 meshing transmission has the advantages of high transmission accuracy, smooth movement, and strong load-bearing capacity, which can meet the stringent requirements of guiding accuracy and uniform driving force for core pulling in bending pipes, and ensure synchronous movement of core pulling on both sides on the bending axis.

[0037] In an embodiment of the present invention, the rotating part 601 includes a main shaft 6011, a central gear 6012, a driven gear 6013, and a rotating block 6014. The main shaft 6011 is rotatably disposed in the lower mold base 2. The central gear 6012 is fixedly sleeved in the middle of the main shaft 6011 and meshes with the plate rack 504. The driven gear 6013 is fixedly sleeved in one end of the main shaft 6011 and meshes with the rotating block 6014.

[0038] In this invention, the rack and pinion 504 meshes with and drives the central gear 6012 to rotate. The central gear 6012 drives the main shaft 6011 to rotate, and the main shaft 6011 drives the driven gear 6013 at its end to rotate synchronously. The driven gear 6013 then meshes with and drives the rotating block 6014 to swing. The rotating block 6014 drives the intake unit 604 and the molding part 602 to move along the bending trajectory. This invention, through a multi-stage gear transmission mechanism composed of the main shaft 6011, the central gear 6012, the driven gear 6013, and the rotating block 6014, achieves flexible conversion of the bending core pulling motion direction and smooth power transmission. It can achieve precise guidance along the bending axis within the limited space of the lower mold base 2, adapting to the complex orientation of the curved water channel and intake and exhaust passages in the cylinder head top plate.

[0039] In another embodiment of the present invention, a rotating hole 6015 is provided on the rotating block 6014, and the rotating block 6014 is rotatably sleeved on the sliding shaft 6016 through the rotating hole 6015. The sliding shaft 6016 is located inside the lower mold base 2.

[0040] In this invention, the rotating block 6014 is rotatably mounted on the sliding shaft 6016 fixed inside the lower mold base 2 via a rotating hole 6015, allowing the rotating block 6014 to swing stably with the sliding shaft 6016 as the fulcrum. This invention provides reliable rotational support for the rotating block 6014 through the rotational engagement of the rotating hole 6015 and the sliding shaft 6016, ensuring the accuracy of the rotating block 6014's motion trajectory when driving the bent tube core pulling under complex directional loads. Simultaneously, it reduces friction and wear, improves the service life and motion stability of the mechanism, and guarantees the repeatability accuracy of the bent core pulling path.

[0041] In another embodiment of the present invention, the rotating block 6014 is also provided with an arc rack 6017, which meshes with the driven gear 6013.

[0042] In this invention, a rack 6017 is provided on the rotating block 6014. The driven gear 6013 meshes with the rack 6017, converting the rotational motion of the driven gear 6013 into the oscillating motion of the rotating block 6014. This invention uses a transmission method of meshing the rack 6017 with a gear, which has the advantages of small meshing clearance, smooth transmission, and high load-bearing capacity. The arc-shaped design of the rack 6017 allows the rotating block 6014 to move according to a preset bending trajectory, precisely controlling the insertion angle and depth of the intake unit 604 and the molding part 602 along the bending axis, meeting the forming requirements of the complex curved inner cavity of the cylinder head top plate.

[0043] In an embodiment of the present invention, the molding part 602 includes a core segment 6021, a mounting groove 6022 and a through groove 6023. A plurality of core segments 6021 are movably sleeved on the air intake unit 604 through the through groove 6023. The mounting groove 6022 is opened at both ends of the core segment 6021. The magnetic ionization part 603 is provided on the mounting groove 6022. The ventilation groove group 605 is opened on the core segment 6021.

[0044] In this invention, the molding part 602 is composed of multiple core segments 6021, which are divided and arranged along the bending axis. Each core segment 6021 is movably sleeved on the air intake unit 604 through the through groove 6023 and can slide relative to the air intake unit 604 along the axial direction, so that the front core segment, near the cavity depth and the rear core segment, near the drive device, form a multi-segment dynamic lubrication structure. The core segment 6021 has mounting grooves 6022 at both ends for embedding the magnetic separation part 603. The ventilation groove group 605 is formed on the surface of the core segment 6021. This invention designs the molding section 602 as a multi-core segment 6021 combination structure, enabling it to adapt to the direction of the curved channel. At the same time, the front core segment can generate a slight adaptive angle sway relative to the rear core segment during the extraction process, avoiding the huge obstruction resistance caused by the rigid connection of the traditional integral tube bending core extraction. The mounting groove 6022 provides reliable installation positioning for the magnetic separation section 603. The through groove 6023 ensures smooth sliding of the core segment 6021 on the air intake unit 604, so that each core segment 6021 can be smoothly separated to generate tiny gaps during demolding, realizing low-resistance and stable demolding of complex curved cavities.

[0045] In an embodiment of the present invention, the magnetic separation part 603 includes a magnetic ring 6031, which is embedded in the opposite end faces of adjacent segments of the molding part 602. Magnetic sheets are arranged in annular intervals inside the magnetic ring 6031, so that when the mold is closed, the magnetic rings 6031 on adjacent segments attract each other through opposite magnetic poles, thereby positioning each segment of the molding part 602 in the circumferential direction at a preset angle.

[0046] In this invention, the magnetic separation part 603 includes a magnetic ring 6031 embedded in the opposite end faces of adjacent segments. Magnetic sheets are arranged in a ring at equal intervals within the magnetic ring 6031. During mold closing, the magnetic rings 6031 on adjacent segments attract each other through the opposite magnetic poles of the magnetic sheets. This not only provides axial attraction to ensure a tight fit between the segment end faces, but also, through the circumferential magnetic force of the equally spaced magnetic sheets, automatically positions each segment to a preset angle in the circumferential direction. This ensures the circumferential alignment accuracy between the core segments 6021 and prevents segment misalignment caused by uneven force during bending and core pulling. Through the magnetic pole arrangement design of the magnetic ring 6031, this invention achieves both axial attraction and circumferential positioning between segments during mold closing, avoiding dimensional deviations in the casting's bending holes caused by circumferential misalignment. It also eliminates the need for complex mechanical positioning structures and simplifies the mold assembly process.

[0047] In another embodiment of the present invention, the magnetic ring 6031 is an electromagnet, and the magnetic ionization part 603 further includes a conductive slip ring embedded in the lower mold base 2, and the conductive slip ring is electrically connected to the magnetic ring 6031. The conductive slip ring is used to connect to an external power source. When the mold is closed, the magnetic ring 6031 generates a magnetic force to attract adjacent segments. When the mold is demolded, the power is turned off to make the magnetic force disappear.

[0048] In this invention, the magnetic ring 6031 is an electromagnet, and the magnetic ionization part 603 also includes a conductive slip ring embedded in the lower mold base 2. The conductive slip ring is electrically connected to the magnetic ring 6031 and is connected to an external power source. One end core segment of the molding section 602 on one side is embedded with a permanent magnet, and the other end core segment of the molding section 602 on the other side is embedded with an electromagnet, forming a bidirectional end self-seeking locking mechanism. When the mold is closed, the conductive slip ring is energized, causing the electromagnet to generate a magnetic field with the opposite polarity to that of the permanent magnet. The two generate a strong attraction force, which precisely attracts the ends of the two front guide segments together to form a rigid whole, ensuring that the curved channel formed by the two bent tube core pullings together during the filling process has the highest dimensional accuracy and stability. When demolding, the conductive slip ring is de-energized, causing the magnetic force to disappear, the attraction force to be released, and the ends of the two front guide segments to separate, each of which performs adaptive yaw to exit with minimal resistance.

[0049] In another embodiment of the present invention, the air intake unit 604 includes an air passage 6041, an end block 6042, an air intake duct 6043, and an end block 6044. The air passage 6041 is opened on the rotating part 601, the end block 6042 is fixedly disposed on the rotating part 601, the air intake duct 6043 is fixedly disposed at the end of the end block 6042 away from the rotating part 601, the end block 6044 is disposed at the end of the air intake duct 6043 away from the end block 6042, and the molding part 602 is movably sleeved on the air intake duct 6043.

[0050] In this invention, the intake tube 6043 is made of semi-hard stainless steel thin-walled tube with a wall thickness of 0.3mm-0.8mm. It has sufficient structural rigidity to support the forming part 602 to form a stable cavity, and also has a small amount of elastic deformation capability, which can adapt to the slight deviation of the bending axis during the core pulling process. The end block 6042 and the end block 6044 are both embedded with magnetic rings 6031 at one end near the intake tube 6043. The magnetic rings 6031 at both ends respectively attract the core segments 6021 sleeved at the beginning and end of the intake tube 6043, ensuring that the beginning and end core segments are accurately positioned and tightly fitted when the mold is closed.

[0051] In an embodiment of the present invention, the ventilation slot assembly 605 includes an air outlet 6051 and an air curtain hole 6052. A plurality of air outlets 6051 are arranged in an annular pattern at equal intervals on the air inlet tube 6043, and the air curtain holes 6052 are arranged in an annular pattern at equal intervals on the molding part 602. The air passage 6041, the air inlet tube 6043, the air outlets 6051 and the air curtain holes 6052 are connected.

[0052] In the casting filling and holding pressure stages of this invention, low-pressure inert gas is continuously introduced into the air inlet tube 6043 through the air channel 6041 via an external air source. The gas seeps out evenly from the capillary gaps at the front end of the forming part 602 and the air curtain hole 6052, forming an extremely thin micro air cushion between the surface of the forming part 602 and the not-yet-fully-solidified molten metal. On the one hand, this effectively isolates the molten metal from direct contact with the surface of the forming part 602, reducing the adhesion force of the initial solidified shell. On the other hand, the seeping gas carries the air at the bottom of the curved cavity and is discharged through the parting surface, realizing forced venting of the curved cavity and solving the problem of air entrapment and porosity defects at the bend. During demolding, the gas ejected from the air curtain hole 6052 forms auxiliary lubrication in the tiny pores between the segments, further reducing demolding resistance.

[0053] This invention, through the coordinated design of the vent hole 6051 and the air curtain hole 6052, enables the bent tube core pulling to function as an "vent" to eliminate air hole defects during the filling stage and as a "lubricator" to reduce frictional resistance during the core pulling stage. This achieves an optimized design of "one structure, two functions", which significantly improves the casting quality and demolding smoothness of the bent channel.

[0054] As another embodiment of the present invention, the anti-clogging mechanism of the air curtain orifice 6052 is further explained as follows: Those skilled in the art should understand that molten aluminum alloy has a high surface tension of approximately 0.8-1.0 N / m, and its capillary permeability is limited under the pressure conditions of low-pressure casting. The pore size of the air curtain orifice 6052 of the present invention is designed to be at the micropore level, preferably in the range of 0.1 mm-0.3 mm. During casting filling, a continuously introduced low-pressure inert gas, with a pressure slightly higher than the static pressure head of the molten metal, typically 5-10 kPa higher, forms a stable positive pressure barrier at the outlet of the air curtain orifice 6052. This gas pressure, combined with the surface tension of the molten metal, prevents the molten metal from overcoming capillary forces to enter the micropores, thereby ensuring the long-term unobstructed flow of the air curtain orifice 6052.

[0055] Furthermore, during the pressure-holding solidification stage, a very thin oxide film first forms on the surface of the molten metal. This oxide film has a certain degree of density and strength, further preventing the molten metal from penetrating into the micropores. Even in rare cases where a trace amount of molten metal touches the edge of the orifice, it will solidify preferentially and form a metal plug. However, during subsequent demolding and core pulling, due to the continuous action of the micro-air cushions and the tiny pores created by segment separation, the metal plug is very easy to break off and will not cause permanent blockage of the air curtain orifice 6052.

[0056] Working Principle: This embodiment provides a multi-directional core-pulling low-pressure casting mold for engine cylinder heads. In use, the core-pulling mechanism 5 is first driven by cylinder 502, which in turn drives the plate rack 504 to move linearly via clamping plate 503. The plate rack 504 meshes with the central gear 6012 of the rotating part 601, driving the central gear 6012 to rotate. The central gear 6012 drives the driven gear 6013 to rotate synchronously via the main shaft 6011. The driven gear 6013 meshes with the arc rack 6017 on the rotating block 6014, driving the rotating block 6014 to swing around the sliding shaft 6016. The rotating block 6014 drives the intake unit 604, which is fixedly connected to it, and the forming part 602 sleeved on the intake tube 6043 to move along the bending axis, causing the forming part 602 to insert into the mold 4 under the top plate. In the closed state, the magnetic separation part 603 is embedded in the mounting grooves 6022 at both ends of each core segment 6021 of the forming part 602. The magnetic ring 6031 uses the attraction of opposite magnetic sheets arranged at equal intervals in its inner ring to precisely position and tightly fit each core segment 6021 in the circumferential direction to form a complete curved cavity. During the casting filling and pressure holding stages, an external air source introduces low-pressure inert gas through the air channel 6041 and the air inlet pipe 6043. The gas seeps out evenly from the air outlet 6051 on the air inlet pipe 6043 and the air curtain hole 6052 on the core segment 6021, forming a micro air cushion between the surface of the forming part 602 and the molten metal, achieving forced venting and reducing adhesion. During demolding, the magnetic ring 6031 is first de-energized by the conductive slip ring, causing the magnetic force between adjacent segments to disappear. Small gaps are generated between each core segment 6021 to release the clamping force. At the same time, the gas ejected from the air curtain hole 6052 forms auxiliary lubrication at the gaps. Then, the core pulling mechanism 5 drives in the opposite direction, allowing the forming part 602 to smoothly exit from the curved cavity of the casting, completing the demolding.

[0057] 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 multi-directional core-pulling low-pressure casting mold for engine cylinder heads, characterized in that, It includes an upper mold base (1) and a lower mold base (2). The upper mold base (1) is provided with a top plate mold (3), and the lower mold base (2) is provided with a top plate lower mold (4). The lower mold base (2) is symmetrically provided with a core pulling mechanism (5). The lower mold base (2) is provided with a core mechanism (6). The core mechanism (6) is engaged with the core pulling mechanism (5). The output end of the core mechanism (6) is movably inserted into the top plate lower mold (4). The core mechanism (6) includes a rotating part (601), a molding part (602), a magnetic ionization part (603), an air intake unit (604), and a ventilation slot group (605). The molding section (602) is composed of multiple segments; The rotating part (601) is rotatably disposed in the lower mold base (2) and engages with the core pulling mechanism (5). It is used to rotate under the drive of the core pulling mechanism (5) and drive the air intake unit (604) and the molding part (602) to move so as to insert or withdraw from the lower mold of the top plate (4). The air intake unit (604) is fixedly connected to the end of the rotating part (601) away from the lower mold base (2); The molding part (602) is sleeved on the air intake unit (604); The magnetic ionization part (603) is embedded between the segments of the molding part (602) and is used to disconnect the magnetic force during demolding, so as to create tiny gaps between the segments to facilitate demolding. The ventilation slot group (605) is provided on the air intake unit (604) and the molding part (602) for ventilation during casting.

2. The multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 1, characterized in that, The core-pulling mechanism (5) includes a mounting frame (501), a cylinder (502), a clamping plate (503), and a plate rack (504). The mounting frame (501) is symmetrically fixed on the lower mold base (2). The cylinder (502) is mounted on the mounting frame (501). The clamping plate (503) is fixedly connected to the output end of the cylinder (502). The plate rack (504) is fixedly connected to the clamping plate (503) and meshes with the rotating part (601).

3. The multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 2, characterized in that, The rotating part (601) includes a main shaft (6011), a central gear (6012), a driven gear (6013), and a rotating block (6014). The main shaft (6011) is rotatably disposed in the lower mold base (2). The central gear (6012) is fixedly sleeved in the middle of the main shaft (6011). The central gear (6012) meshes with the plate rack (504). The driven gear (6013) is fixedly sleeved at one end of the main shaft (6011). The driven gear (6013) meshes with the rotating block (6014).

4. The multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 3, characterized in that, The rotating block (6014) has a rotating hole (6015), and the rotating block (6014) is rotatably sleeved on the sliding shaft (6016) through the rotating hole (6015). The sliding shaft (6016) is located inside the lower mold base (2).

5. A multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 3, characterized in that, The rotating block (6014) is also provided with an arc rack (6017), which meshes with the driven gear (6013).

6. The multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 1, characterized in that, The molding part (602) includes a core segment (6021), a mounting groove (6022), and a through groove (6023). A plurality of the core segments (6021) are movably sleeved on the air intake unit (604) through the through groove (6023). The mounting groove (6022) is opened at both ends of the core segment (6021). The magnetic ionization part (603) is provided on the mounting groove (6022). The ventilation groove group (605) is opened on the core segment (6021).

7. A multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 1, characterized in that, The magnetic separation part (603) includes a magnetic ring (6031), which is embedded in the opposite end face of adjacent segments of the molding part (602). Magnetic sheets are arranged in a ring at equal intervals inside the magnetic ring (6031) so that when the mold is closed, the magnetic rings (6031) on adjacent segments attract each other through opposite magnetic poles, thereby positioning each segment of the molding part (602) in the circumferential direction to a preset angle.

8. A multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 7, characterized in that, The magnetic ring (6031) is an electromagnet, and the magnetic ionization part (603) also includes a conductive slip ring embedded in the lower mold base (2), and the conductive slip ring is electrically connected to the magnetic ring (6031); The conductive slip ring is used to connect to an external power source. When the mold is closed, the power is applied to the magnetic ring (6031) to generate magnetic force to attract adjacent segments. When the mold is demolded, the power is cut off to make the magnetic force disappear.

9. A multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 1, characterized in that, The air intake unit (604) includes an air passage (6041), an end block (6042), an air intake tube (6043), and an end block (6044). The air passage (6041) is opened on the rotating part (601). The end block (6042) is fixedly disposed on the rotating part (601). The air intake tube (6043) is fixedly disposed at the end of the end block (6042) away from the rotating part (601). The end block (6044) is disposed at the end of the air intake tube (6043) away from the end block (6042). The molding part (602) is movably sleeved on the air intake tube (6043).

10. A multi-directional core-pulling low-pressure casting mold for engine cylinder heads according to claim 9, characterized in that, The ventilation slot assembly (605) includes an air outlet (6051) and an air curtain hole (6052). A plurality of the air outlets (6051) are arranged in a ring at equal intervals on the air inlet tube (6043), and the air curtain holes (6052) are arranged in a ring at equal intervals on the molding part (602). The air passage (6041), the air inlet tube (6043), the air outlets (6051) and the air curtain holes (6052) are connected.

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