Hot runner structure of semi-solid magnesium alloy die-casting mold

Abstract

The application relates to the technical field of molds, and particularly discloses a hot runner structure of a semi-solid magnesium alloy die-casting mold, which comprises a main runner structure and at least one sub-flow nozzle connected with the main runner structure, a sub-flow cavity is formed in the sub-flow nozzle, a valve needle is arranged in the sub-flow cavity, an outer wall of the valve needle is sleeved with a spiral sleeve, an outer wall of the spiral sleeve is provided with spiral guide protrusions, and intervals for fluid passing are formed between the spiral guide protrusions and an inner wall of the sub-flow cavity; and the spiral sleeve is connected with a conductive mechanism for axial displacement. The hot runner structure of the application considers both flow path optimization and real-time state monitoring, so that the stability of a semi-solid magnesium alloy die-casting process and forming quality are improved.

Description

A hot runner structure for a semi-solid magnesium alloy die casting mold Technical Field

[0001] This invention relates to the field of mold technology, specifically to a hot runner structure for a semi-solid magnesium alloy die-casting mold. Background Technology

[0002] Currently, the semi-solid magnesium alloy die casting process suffers from significant challenges due to complex fluid states and uneven solid-liquid phase distribution during mold forming. Because magnesium alloys in a semi-solid state simultaneously contain both liquid and solid particles, the liquid phase has low viscosity and flows rapidly, while the solid particles have larger diameters and poor flowability, easily causing blockages, stagnation, or localized accumulation in the runner, leading to incomplete mold filling or unstable part performance. Existing hot runner structures typically rely on a single-channel feeding system, lacking guidance design for the differentiated flow paths of the solid and liquid phases. Insufficient heating time for solid particles results in poor melting uniformity, leading to uneven internal structure and decreased mechanical properties in the part. Furthermore, traditional runner structures rely heavily on high-temperature sensors for condition monitoring, which suffers from poor reliability, maintenance difficulties, and significant interference with the internal structure of the runner. Therefore, there is an urgent need for a hot runner structure that can optimize flow paths and monitor conditions in real time to improve the stability and forming quality of the semi-solid magnesium alloy die casting process. Summary of the Invention

[0003] This application provides a hot runner structure for a semi-solid magnesium alloy die-casting mold. The main purpose of this hot runner structure is to combine flow path optimization with real-time status monitoring, so as to improve the stability and molding quality of the semi-solid magnesium alloy die-casting process.

[0004] To achieve the above objectives, this application provides a hot runner structure for a semi-solid magnesium alloy die-casting mold, including a main runner structure and at least one branch nozzle connected to the main runner structure. A branch cavity is formed in the branch nozzle, and a valve needle is disposed in the branch cavity.

[0005] The outer wall of the valve needle is fitted with a spiral assembly, and the outer wall of the spiral assembly is provided with a spiral guide protrusion. A gap is formed between the spiral guide protrusion and the inner wall of the flow divider cavity to allow fluid to pass through. The spiral assembly is connected to the axial displacement transmission mechanism.

[0006] In one feasible embodiment, the spiral assembly is axially movable; the transmission mechanism includes a connecting inner rod fixedly connected to the middle of the spiral assembly, the connecting inner rod extending upward and passing through the valve needle to connect with an elastic transmission mechanism disposed on the outside of the mold.

[0007] In one feasible implementation, the elastic transmission mechanism includes a synchronous connecting plate, the bottom end of which is connected to at least one vertical rod, and the vertical rod is fitted with an elastic force-applying element that provides an upward restoring force.

[0008] In one feasible implementation, at least one of the vertical rods serves as a drive rod, and the drive rod is a rack and pinion structure.

[0009] In one feasible implementation, the hot runner structure includes two flow-dividing nozzles, each of which is correspondingly provided with a drive rod; it also includes a status monitoring mechanism, which includes two gears respectively meshing with the drive rod, a transmission rod driven by the gears, and a rotary encoder; the two transmission rods are coaxially arranged, the rotating head of the rotary encoder is connected to one of the transmission rods, and the body of the rotary encoder is connected to the other transmission rod.

[0010] In one feasible implementation, the gap between the spiral assembly and the inner wall of the diversion cavity forms a straight channel that allows fluid to pass directly through, and a spiral channel is formed between the spiral guide protrusion and the inner wall of the diversion cavity.

[0011] In one possible implementation, the spiral assembly is a fixed assembly whose position is fixed relative to the valve needle.

[0012] In one feasible implementation, each of the drive rods is independently connected to a rotary encoder, and the rotating head of the rotary encoder is linked to the displacement of the drive rod.

[0013] This application provides a hot runner structure for a semi-solid magnesium alloy die-casting mold. By setting a spiral assembly on the outer wall of the valve needle and utilizing the straight and spiral channels formed between the spiral guide protrusion and the inner wall of the flow divider, it achieves differentiated guidance for the rapid flow of liquid substances and the extended heating path of solid particles, effectively improving the melting uniformity of solid particles and the overall heating efficiency, and avoiding flow channel blockage. At the same time, the spiral assembly, combined with an axially displaceable transmission mechanism and an external synchronous connecting plate, can not only dynamically adjust the flow path according to fluid resistance, but also convert the internal flow state into external mechanical displacement, achieving sensor-free state monitoring. Furthermore, the combined design of the vertical rod, elastic force application element, and rack and pinion drive structure ensures the stability of the spiral assembly's reset and displacement signal output. When using a dual-flow nozzle, synchronous or differential monitoring of the dual flow channels can be achieved using a coaxial transmission rod and a rotary encoder, while in multi-point sequential injection scenarios, independent monitoring of each flow channel is supported, thus balancing process diversity and monitoring accuracy. Compared with existing technologies, this application not only optimizes the flow path of the solid and liquid phases of semi-solid magnesium alloys, but also improves the reliability of condition monitoring through mechanical linkage, and has the comprehensive advantages of reasonable structure, stable operation, sensitive detection and convenient maintenance. Attached Figure Description

[0014] Figure 1 shows a three-dimensional structural schematic diagram of the hot runner structure of the semi-solid magnesium alloy die-casting mold provided in the embodiment of this application;

[0015] Figure 2 shows a side view structural schematic diagram provided in an embodiment of this application;

[0016] Figure 3 shows a schematic cross-sectional view of the flow-dividing nozzle provided in an embodiment of this application;

[0017] Figure 4 shows a partial enlarged structural diagram of point A in Figure 3;

[0018] Figure 5 shows a schematic diagram of the bottom strip hole provided in an embodiment of this application;

[0019] Figure 6 shows a schematic diagram of the structure of the spiral guide protrusion provided in an embodiment of this application;

[0020] Figure 7 shows a schematic diagram of the drive rod provided in an embodiment of this application;

[0021] Figure 8 shows a schematic diagram of the structure of the status monitoring mechanism provided in an embodiment of this application;

[0022] Figure 9 shows a schematic diagram of the structure of the status monitoring mechanism provided in this application when it consists of multiple rotary encoders;

[0023] Figure 10 shows a magnified schematic diagram of the structure at point B in Figure 8.

[0024] In the diagram: 10, main runner structure; 20, hot runner cavity plate; 30, split nozzle; 40, drive assembly; 60, elastic conduction mechanism; 70, condition monitoring mechanism; 100, solid particles.

[0025] 31. Diverting heating device; 32. Heating tube; 33. Interface; 34. Diverting chamber; 35. Heating nozzle.

[0026] 341. Straight channel; 342. Spiral channel.

[0027] 41. Cylinder; 42. Valve needle; 43. Helical assembly; 44. Connecting inner rod.

[0028] 61. Synchronous connecting plate; 62. Vertical rod; 63. Elastic force-applying component; 64. Drive rod.

[0029] 71. Drive rod; 72. Rotary encoder; 73. Rotary head; 74. Gear; 75. Heat insulation sheet.

[0030] 421. Bottom strip hole; 422. Top adjustment hole; 423. Locking end.

[0031] 431. Spiral guide protrusion. Detailed Implementation

[0032] To better understand the technical solutions provided in the embodiments of this specification, the technical solutions of the embodiments of this specification will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0033] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The term "two or more" includes two or more cases.

[0034] Please refer to Figures 1 to 10. This application provides a hot runner structure for a semi-solid magnesium alloy die-casting mold, including a main runner structure 10 and at least one diversion nozzle 30 connected to the main runner structure 10. The diversion nozzle 30 and the main runner structure 10 are respectively disposed at corresponding positions at the top and bottom of the hot runner cavity plate 20. A diversion cavity 34 is formed in the diversion nozzle 30, and a valve needle 42 is disposed in the diversion cavity 34. The valve needle 42 is driven to extend and retract by a drive assembly 40 disposed above the hot runner cavity plate 20 to realize the opening and closing function of the diversion cavity 34. The drive assembly 40 can be configured as a cylinder.

[0035] The outer wall of the valve needle 42 is fitted with a spiral assembly 43, and the outer wall of the spiral assembly 43 is provided with a spiral guide protrusion 431. A gap for fluid to pass through is formed between the spiral guide protrusion 431 and the inner wall of the diversion cavity 34. The spiral assembly 43 is connected to the axial displacement transmission mechanism.

[0036] Therefore, this device achieves full-process control of semi-solid magnesium alloy from injection, diversion, heating optimization to state monitoring through the coordinated operation of the main flow channel structure 10, hot runner cavity plate 20, drive assembly 40, elastic conduction mechanism 60 and condition monitoring mechanism 70, combined with the continuous heat preservation of the diversion heating device 31 (and the heating tube 32 connected to the heating device) and the heating nozzle 35.

[0037] It should be noted that the hot runner structure of the semi-solid magnesium alloy die-casting mold provided in this application optimizes the flow path of solid and liquid phase substances in the semi-solid magnesium alloy through the cooperative design of the spiral assembly 43 and the flow divider 34. The spiral assembly 43 is sleeved on the outer wall of the valve needle 42, and the gap formed between the spiral guide protrusion 431 on its outer wall and the inner wall of the flow divider 34 allows fluid to pass through. When the viscosity of the liquid phase substance in the fluid is low, it can flow quickly directly through the straight channel 341 formed by the gap; while when the solid phase particles 100 have a larger diameter or higher viscosity, they will be guided by the spiral guide protrusion 431 to flow along the spiral channel 342, extending their path and increasing the heating time, thereby improving the melting uniformity of the solid phase particles 100. The connection design between the spiral assembly 43 and the conduction mechanism allows the spiral assembly 43 to be axially displaced according to the fluid state. For example, by feeding back changes in flow resistance through the conduction mechanism, the gap or position of the spiral channel 342 can be dynamically adjusted to further control the optimization effect of the flow path.

[0038] The bottom strip hole 421 and the top adjustment hole 422 on the valve needle 42 are designed to meet the movement requirements of the internal connecting rod 44, so that the connecting rod 44 can be synchronously connected to the spiral assembly 43 and the synchronous connecting plate 61, achieving synchronous movement of the three. The heat insulation sheet 75 ensures the long-term stable operation of the electronic components. The locking end 423 on the top of the valve needle 42 ensures a reliable drive connection to the extension end of the cylinder 41.

[0039] As shown in Figures 3, 4, 6, 7 and 8, in some examples, the spiral assembly 43 is further configured to be axially movable; the transmission mechanism includes a connecting inner rod 44 fixedly connected to the middle of the spiral assembly 43, the connecting inner rod 44 extending upward and passing through the valve needle 42 to connect with the synchronous connecting plate 61 disposed on the outside of the mold.

[0040] In this example, displacement transmission and external control are achieved through the axial movement of the spiral assembly 43 combined with a transmission mechanism. The axially movable characteristic of the spiral assembly 43 allows it to respond to changes in resistance caused by fluid flow, while the fixed connection between the connecting inner rod 44 and the middle of the spiral assembly 43 ensures the stability of displacement transmission. The upward extension of the connecting inner rod 44 through the valve needle 42 transforms the internal flow channel dynamic parameters into externally observable mechanical displacement. The synchronous connecting plate 61 is located on the outside of the mold, which avoids the influence of high temperature on the control mechanism and realizes the synchronous linkage of multi-channel displacement, providing a unified displacement input condition for the subsequent state monitoring mechanism 70. The connection position of the connecting inner rod 44 and the middle of the spiral assembly 43 effectively balances the torque distribution during the transmission process and prevents assembly jamming caused by offset connection; the external layout of the synchronous connecting plate 61 solves the technical obstacles of traditional built-in transmission mechanisms that are difficult to maintain and observe, and also avoids the problems of the influence of direct detection sensors inside the flow channel on the flow channel and the influence of high temperature on the sensors.

[0041] As shown in Figures 6, 7 and 8, in some examples, at least one vertical rod 62 is connected to the bottom end of the synchronous connecting plate 61, and an elastic force-applying member 63 providing an upward restoring force is sleeved on the vertical rod 62.

[0042] In this example, by setting a combination structure of a vertical rod 62 and an elastic force-applying component 63 at the bottom of the synchronous connecting plate 61, the automatic reset function of the spiral assembly 43 after displacement is realized. Specifically, the vertical rod 62, as a rigid carrier for force transmission, directly transmits the displacement of the synchronous connecting plate 61 to the elastic force-applying component 63; while the elastic force-applying component 63, sleeved on the vertical rod 62, stores elastic potential energy when the fluid pressure causes the spiral assembly 43 to move downward, through its elastic deformation characteristics. When the fluid pressure weakens, it releases this potential energy to generate an upward reset force, forcing the vertical rod 62 to drive the synchronous connecting plate 61 back to its initial position. This ensures the real-time transmission of displacement and maintains the initial working position of the spiral assembly 43 through the elastic reset mechanism, enabling it to work continuously and always provide monitoring of the fluid. The vertical rod 62 can adopt a multi-rod parallel structure to enhance reset stability through multi-point force application, while the sleeve arrangement of the elastic force-applying component 63 ensures that its force direction coincides with the axis of motion of the vertical rod 62.

[0043] As shown in Figures 7 and 10, in some examples, at least one of the vertical rods 62 serves as a drive rod 64, which is a rack and pinion structure.

[0044] In this example, the rack and pinion structure of the drive rod 64 converts the axial displacement of the vertical rod 62 into the rotational motion of the gear 74, thereby triggering the signal output of the condition monitoring mechanism 70. Specifically, the drive rod 64, as part of the vertical rod 62, has a rack and pinion structure that meshes with the gear 74 in the condition monitoring mechanism 70, directly converting the axial displacement of the helical assembly 43 caused by fluid resistance into a change in the rotation angle of the gear 74. The design of the rack and pinion structure ensures a linear relationship between the displacement and the rotation angle of the gear 74, guaranteeing the accuracy of displacement detection. At the same time, the gear 74 amplifies small displacements, improving monitoring sensitivity. At least one vertical rod 62 is defined as the drive rod 64, allowing for independent installation of corresponding drive rods 64 in multiple flow-diverting nozzle 30 systems, providing a physical interface 33 for the synchronous or differential detection of the dual transmission rods 71 ​​in the subsequent condition monitoring mechanism 70. Compared with other transmission forms (such as connecting rods or cams), the meshing method of the rack and pinion with the gear 74 has the advantages of compact structure, high transmission efficiency, and no sliding loss, making it suitable for long-term stable operation in the high temperature and high pressure environment of die-casting molds.

[0045] As shown in Figures 6, 7, 8, 9, and 10, in some examples, the hot runner structure further includes two split nozzles 30, each of which is provided with a corresponding drive rod 64; it also includes a condition monitoring mechanism 70, which includes two gears 74 respectively meshing with the drive rods 64, a transmission rod 71 driven by the gears 74, and a rotary encoder 72; the two transmission rods 71 ​​are coaxially arranged, the rotating head 73 of the rotary encoder 72 is connected to one of the transmission rods 71, and the body of the rotary encoder 72 is connected to the other transmission rod 71.

[0046] In this example, linear displacement is converted into rotational motion by setting a drive rod 64 meshing with a gear 74 corresponding to the dual-flow nozzle 30. Two coaxial drive rods 71 ​​are connected to the rotating head 73 and the body of the rotary encoder 72, respectively. When the flow velocities of the two channels are consistent, the drive rods 71 ​​rotate synchronously, resulting in no relative rotation signal output from the encoder. When the flow velocity difference causes the drive rods 64 to move asynchronously, the drive rods 71 ​​rotate relative to each other, and the rotary encoder 72 outputs a difference signal by detecting the relative angle between the rotating head 73 and the body. This achieves real-time monitoring of the synchronous state of the two channels, using mechanical linkage to convert displacement differences into quantifiable rotational angle differences.

[0047] It should also be noted that, for multi-point sequential injection scenarios, each drive rod 64 can be configured to be independently connected to the rotary encoder 72. Time-sharing control is achieved by independently monitoring the displacement of each flow channel, avoiding mutual interference among multiple flow channels. The separate connection between the rotary encoder 72 body and the rotary head 73 retains the synchronous monitoring function while providing a structural basis for independent monitoring.

[0048] As shown in Figure 4, in some examples, the gap between the spiral assembly 43 and the inner wall of the diversion cavity 34 further constitutes a straight channel 341 that allows fluid to pass directly through, and a spiral channel 342 is formed between the spiral guide protrusion 431 and the inner wall of the diversion cavity 34.

[0049] In this example, dual-channel flow control is achieved through the cooperative structure of the spiral assembly 43 and the flow divider 34. The gap between the outer wall of the spiral assembly 43 and the inner wall of the flow divider 34 forms a straight channel 341, allowing low-viscosity liquid substances to pass through quickly and reducing flow resistance. At the same time, the spiral channel 342 formed between the spiral guide protrusion 431 and the inner wall of the flow divider 34 forces solid particles 100 with a diameter larger than the gap of the straight channel 341 to move along the spiral path. The dual-channel structure combines phase separation and path control of the fluid. The straight channel 341 ensures basic flow efficiency, while the spiral channel 342 extends the heating time of the solid particles 100. The combination of the two avoids the solid particles 100 from clogging the flow channel and improves the overall heating uniformity through differentiated paths. The specific geometry of the spiral guide protrusion 431 and the gap fit with the inner wall of the flow divider 34 ensure structural strength while achieving forced deflection of the solid particles 100, while the size of the straight channel 341 is specifically designed based on the differences in the physical properties of the solid and liquid phases.

[0050] As shown in Figure 9, in some examples, each drive rod 64 is further connected to a rotary encoder 72, and the rotating head 73 of the rotary encoder 72 is linked to the displacement of the drive rod 64.

[0051] In this example, to ensure that some molds employ a multi-point sequential injection process, a rotary encoder 72 is individually configured for each drive rod 64 to independently monitor the flow rate or pressure of each flow channel. Each drive rod 64, as a rack and pinion structure, directly reflects the motion state of the helical assembly 43 within the corresponding flow channel. The rotating head 73 of the rotary encoder 72 is linked to the drive rod 64, converting the linear displacement of the drive rod 64 into a rotation signal for the rotary encoder 72, thereby acquiring the dynamic parameters of each flow channel in real time. When the displacement of the drive rod 64 deviates from the set range due to abnormal flow rate in a certain flow channel, the corresponding rotary encoder 72 directly outputs the deviation signal of that flow channel by detecting the relative rotation angle between the rotating head 73 and the main body. This not only meets the monitoring requirements for time-sharing operation of flow channels in multi-point sequential injection but also allows for rapid location of abnormal flow channels through an independent alarm mechanism, avoiding response lag issues caused by global monitoring.

[0052] In some examples, the spiral assembly 43 is further fixed, its position being fixed relative to the valve needle 42.

[0053] In this example, by setting the spiral assembly 43 to be fixed relative to the valve needle 42, the possibility of axial movement of the spiral assembly 43 is directly eliminated. This fixing method makes the spiral assembly 43 and the valve needle 42 form a rigid connection, and the two remain relatively stationary during mold operation. Since the position of the spiral assembly 43 is no longer affected by fluid flow resistance or external drive mechanism, the distance between the spiral guide protrusion 431 on its outer wall and the inner wall of the flow divider 34 remains constant, thereby ensuring the stability of the geometric parameters of the fluid channel. This simplifies the requirements for setting the transmission mechanism and avoids wear and jamming problems that may occur in movable components under high temperature and high pressure environments. At the same time, the fixed shape of the spiral channel 342 can continuously guide the solid particles 100 to flow along the spiral path, ensuring heating uniformity without relying on dynamic adjustment mechanisms. Those skilled in the art can flexibly choose the appropriate implementation method according to the actual fluid parameters and experiments.

[0054] The working principle of this device is as follows:

[0055] Working process when the spiral assembly 43 is a movable structure:

[0056] With the spiral assembly 43 movable, this device achieves dynamic response and real-time monitoring of the fluid state. Its operation is a closed-loop electromechanical linkage.

[0057] Step 1: Under pressure, the semi-solid magnesium alloy enters the flow-dividing chamber 34 of the flow-dividing nozzle 30 through the main flow channel structure 10. Due to its low viscosity and small particle size, the liquid phase in the fluid mainly passes through the gap (i.e., the straight channel 341) between the spiral assembly 43 and the inner wall of the flow-dividing chamber 34. However, the solid phase particles 100 in the fluid, due to their larger diameter or higher viscosity, cannot pass directly through this gap and are forced into the spiral channel 342 formed by the spiral guide protrusion 431 and the inner wall of the flow-dividing chamber 34. This process prolongs the flow path of the solid phase particles 100, allowing them to be heated for a longer period during flow, thereby promoting melting and improving the overall uniformity of the fluid.

[0058] Step Two: When the fluid velocity or pressure within the flow channel changes (due to material jamming or changes in flow channel parameters), the flow resistance acting on the spiral assembly 43 also changes accordingly. If the flow velocity increases and the resistance strengthens, this resistance will overcome the restoring force of the elastic force-applying element 63, pushing the spiral assembly 43 downward along the axial direction of the valve needle 42. The displacement is precisely transmitted to the synchronous connecting plate 61 on the outside of the mold through the connecting inner rod 44 fixedly connected to the middle of the spiral assembly 43.

[0059] Signal conversion: The downward movement of the synchronous connection plate 61 causes the vertical rod 62 at its bottom to move together. The vertical rod 62, which acts as the drive rod 64 (rack structure), converts linear displacement into rotational motion of the gear 74 that meshes with it.

[0060] Step 3: In the system with two diverting nozzles 30, two drive rods 64 drive two gears 74 respectively. Gears 74 drive transmission rods 71 ​​to rotate. The two transmission rods 71 ​​are coaxially arranged and connected to the rotating head 73 and the main body of the rotary encoder 72 respectively. If the flow velocities in the two channels are the same, the displacements of the two drive rods 64 are the same, the transmission rods 71 ​​rotate synchronously, there is no relative rotation inside the rotary encoder 72, and no signal output. If the flow velocity and pressure are inconsistent, there is a speed difference between the transmission rods 71, causing the rotating head 73 of the rotary encoder 72 to rotate relative to the main body. The rotary encoder 72 immediately outputs an electrical signal corresponding to the difference, which can trigger the alarm device.

[0061] Step 4: In the non-injection state, when the pressure in the flow channel decreases and the flow resistance decreases, the compressed elastic force-applying component 63 releases the stored elastic potential energy, pushing the vertical rod 62 and the synchronous connecting plate 61 to reset upwards. Finally, the spiral assembly 43 is pulled back to the initial high position through the connecting inner rod 44, ready for the next working cycle.

[0062] Working process when the spiral assembly 43 is a fixed structure:

[0063] In this mode, unlike the previous mode, the spiral assembly 43 is rigidly connected to the valve needle 42, and its position remains fixed. The spacing between the spiral guide protrusion 431 on its outer wall and the inner wall of the flow divider 34 (straight channel 341) and the geometry of the spiral channel 342 remain constant. The injected semi-solid magnesium alloy fluid is automatically separated in the flow divider 34 according to the physical properties of the solid and liquid phases. The liquid phase still flows through the straight channel 341 to ensure basic flow efficiency; the solid particles 100 are guided by the fixed spiral channel 342 and forced to flow along the spiral path. Throughout the process, the spiral channel 342 always provides a fixed and extended heating path for the solid particles 100, ensuring that they have a stable time to be fully heated, thereby improving melting uniformity. This solution eliminates the need for complex displacement transmission and monitoring mechanisms, resulting in a more robust and reliable structure, suitable for applications with stable operating conditions or where real-time feedback is not required.

[0064] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A hot runner structure for a semi-solid magnesium alloy die-casting mold, comprising a main runner structure (10) and at least one branch nozzle (30) connected to the main runner structure (10), wherein a branch cavity (34) is formed within the branch nozzle (30), and a valve needle (42) is disposed within the branch cavity (34), characterized in that: The outer wall of the valve needle (42) is fitted with a spiral assembly (43), and the outer wall of the spiral assembly (43) is provided with a spiral guide protrusion (431). A gap for fluid to pass through is formed between the spiral guide protrusion (431) and the inner wall of the diversion cavity (34). The spiral assembly (43) is connected to the axial displacement transmission mechanism. The gap between the spiral assembly (43) and the inner wall of the diversion cavity (34) forms a straight channel (341) that allows fluid to pass directly through. A spiral channel (342) is formed between the spiral guide protrusion (431) and the inner wall of the diversion cavity (34).

2. The hot runner structure of the semi-solid magnesium alloy die-casting mold according to claim 1, characterized in that: The spiral assembly (43) is axially movable; the transmission mechanism includes a connecting inner rod (44) fixedly connected to the middle of the spiral assembly (43), the connecting inner rod (44) extending upward and passing through the valve needle (42) and connecting to an elastic transmission mechanism (60) disposed on the outside of the mold.

3. The hot runner structure of the semi-solid magnesium alloy die-casting mold according to claim 2, characterized in that: The elastic transmission mechanism (60) includes a synchronous connecting plate (61), at least one vertical rod (62) is connected to the bottom end of the synchronous connecting plate (61), and an elastic force-applying member (63) that provides an upward restoring force is sleeved on the vertical rod (62).

4. The hot runner structure of the semi-solid magnesium alloy die-casting mold according to claim 3, characterized in that: At least one of the vertical rods (62) serves as a drive rod (64), and the drive rod (64) is a rack and pinion structure.

5. The hot runner structure of the semi-solid magnesium alloy die-casting mold according to claim 4, characterized in that: The hot runner structure includes two flow-dividing nozzles (30), each of which is provided with a corresponding drive rod (64); it also includes a status monitoring mechanism (70), which includes two gears (74) respectively meshing with the drive rod (64), a transmission rod (71) driven by the gears (74), and a rotary encoder (72); the two transmission rods (71) are coaxially arranged, the rotating head (73) of the rotary encoder (72) is connected to one of the transmission rods (71), and the body of the rotary encoder (72) is connected to the other transmission rod (71).

6. The hot runner structure of the semi-solid magnesium alloy die-casting mold according to claim 1, characterized in that: The spiral assembly (43) is a fixed assembly, and its position is fixed relative to the valve needle (42).

7. The hot runner structure of the semi-solid magnesium alloy die-casting mold according to claim 5, characterized in that: Each of the drive rods (64) is independently connected to a rotary encoder (72), and the rotating head (73) of the rotary encoder (72) is linked to the displacement of the drive rod (64).

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