Die-casting forming die for robot joint part

Abstract

The invention relates to a die-casting forming die for robot joint parts, and belongs to the technical field of die casting. The robot joint part die-casting forming die comprises a die body and a sliding block, a forming cavity used for forming a product is formed in the die body, and the die body is further provided with a plurality of guide sliding grooves communicating with the forming cavity; the sliding block is arranged in the guide sliding groove and comprises a structural face and a working face spliced with the inner wall face of the forming cavity. Wherein an exhaust area is arranged in the edge area where the working face and the forming cavity are spliced, and the exhaust area is made of sintered metal only allowing gas to pass through; and a plurality of exhaust passages are further arranged in the sliding block, extend to the structural surface and are used for exhausting gas passing through the exhaust area. According to the die-casting forming die for the robot joint part, air can be efficiently exhausted, and back seepage of forming liquid is prevented.

Description

Technical Field

[0001] This application relates to the field of die casting technology, and more specifically, to a die casting mold for robot joint parts. Background Technology

[0002] Robot joint components (such as wrist and elbow housings) are typically characterized by complex structures, uneven wall thickness, and convoluted surfaces. In die casting production, multiple sliders are often used to achieve multi-directional core pulling for smooth demolding. The working surfaces of these sliders fit against the inner wall of the mold cavity, and closed or semi-closed gas accumulation zones can easily form at their joint edges. If the gas in these areas cannot be discharged in time during high-speed injection, it will lead to defects such as porosity, under-casting, or surface flow marks in the casting, affecting the mechanical properties and appearance quality of the product.

[0003] The common venting methods for die casting molds currently have significant limitations in this application scenario: First, it is common practice to open venting grooves on the mold parting surface, but for complex molding cavities containing multiple sliders, the joints are often far from the main parting surface, and the gas has to travel a long distance to be discharged, resulting in low venting efficiency; Second, if venting micropores are directly machined on the slider joint surface, if the pore diameter is too small, it will be difficult to machine and easy to block, while if the pore diameter is slightly larger, it will not be able to prevent the intrusion of high-pressure molding fluid, and will instead form flash and cause the venting function to fail.

[0004] Therefore, designing an efficient venting structure that prevents the backflow of molding liquid from the multi-slider die-casting mold, which is tailored to the structural characteristics of complex components such as robot joint parts, has become a pressing technical problem in this field. Summary of the Invention

[0005] The purpose of this application is to address the above-mentioned problems by providing a die-casting mold for robot joint parts, which can efficiently vent air and prevent the backflow of molding liquid, thereby improving the above-mentioned problems.

[0006] This application is achieved through the following technical solution: This application provides a die-casting mold for robot joint parts. The die-casting mold for robot joint parts includes a mold body and a slider. The mold body has a molding cavity for molding the product inside, and the mold body also has multiple guide grooves communicating with the molding cavity. The slider is disposed in the guide grooves and includes a structural surface and a working surface that fits into the inner wall of the molding cavity. A venting zone is provided at the edge area where the working surface fits into the molding cavity. The venting zone is made of sintered metal that only allows gas to pass through. Multiple venting channels are also provided inside the slider and extend to the structural surface of the slider. The venting channels are used to discharge the gas passing through the venting zone.

[0007] In the technical solution of this application embodiment, the molding die directly sets the venting point in the venting area at the edge of the slider assembly where gas is most likely to accumulate, achieving source venting. The gas venting path is short and efficient, reducing or even eliminating defects such as porosity, undercasting, and surface flow marks in the casting caused by gas retention. This improves the internal density, mechanical properties, and surface quality of high-requirement structural components such as robot joint parts. The microporous structure of the venting area, composed of sintered metal, acts as a filter, reliably blocking high-pressure molding fluid while allowing gas to pass through. This solves the problem of metal flash and blockage failure that easily occur when directly opening venting holes in the assembly area, ensuring the long-term effectiveness of the venting structure.

[0008] In some embodiments, the slider is further provided with an exhaust chamber and an exhaust duct connecting the exhaust chamber to the external space; the exhaust duct connects to the exhaust chamber.

[0009] In the technical solution of this application embodiment, multiple dispersed exhaust outlets are converged into a unified exhaust outlet, simplifying the complexity of the connection between the slider and the outside of the mold. This makes the external piping or sealing treatment of the mold simpler, improving the convenience of mold assembly and maintenance. The exhaust chamber, as a buffer and pressure equalization space, can balance the airflow pressure from different exhaust channels, making the exhaust from each exhaust zone more balanced and stable. Simultaneously, the concentrated gas is discharged through an exhaust channel with a potentially larger cross-sectional area, reducing flow resistance and facilitating rapid and concentrated gas discharge at critical moments, further improving exhaust efficiency.

[0010] In some embodiments, a guide wall is provided inside the exhaust chamber, and the guide wall spirals from the inside to the outside to form a spiral flow channel, with the inlet of the spiral flow channel connecting to the outlet of the exhaust channel.

[0011] In the technical solution of this application embodiment, the spiral flow channel exerts a forced guiding effect on the gas flow, integrating multiple potentially turbulent and opposing airflows into a single, orderly flow rotating forward. This significantly reduces the flow resistance and pressure loss of the gas in the exhaust chamber, achieving faster and smoother centralized exhaust. The spiral-forward airflow pattern creates a certain directional inertia, which helps suppress the slight reverse gas flow (backflow) that may occur during injection pressure fluctuations or solidification shrinkage of the molding liquid, ensuring the unidirectional stability of the exhaust and avoiding surface defects in the casting that may be caused by airflow disturbance.

[0012] In some embodiments, the exhaust chamber is a columnar structure; the central axis of the spiral flow channel coincides with the central axis of the exhaust chamber; the exhaust duct communicates with the circumferential inner wall of the exhaust chamber; the spiral flow channel is configured to guide the gas entering from its central inlet along a spiral trajectory to the exhaust duct at the circumferential inner wall of the exhaust chamber.

[0013] In the technical solution of this application embodiment, the combination of columnar structure and coaxial spiral flow channel makes the airflow organization orderly and predictable. This design can effectively avoid local eddies and dead zones, making the pressure loss (pressure drop) calculation on the entire exhaust path more accurate and the working state more stable.

[0014] In some embodiments, a plurality of air outlets are evenly arranged along the circumferential inner wall of the exhaust chamber.

[0015] In the technical solution of this application embodiment, multiple exhaust ducts provide a larger total exhaust outlet cross-sectional area, reducing the flow resistance of gas in the final exhaust stage. At critical moments when the molding liquid fills at high speed and a large amount of gas is generated instantaneously, the system can exhaust the gas with lower back pressure and faster speed, enhancing the exhaust capability to cope with injection peaks and reducing the risk of defects caused by insufficient instantaneous exhaust. The uniformly arranged exhaust ducts ensure that gas is evenly drawn away from the outer periphery of the spiral flow channel, avoiding airflow asymmetry or local turbulence that may be caused by unilateral extraction. Simultaneously, multiple outlets constitute a simple redundant system. Even if the flow capacity of individual exhaust ducts temporarily decreases due to external accidents (such as slight obstruction by foreign objects), the remaining exhaust ducts can still ensure continuous effective exhaust function, significantly improving the operational reliability and robustness of the exhaust system. Distributing the exhaust load to multiple outlets avoids the concentrated impact of large-flow gas on a single exhaust duct, which helps extend the service life of these components. At the same time, it also reduces the impact of processing errors or minor blockages at a single outlet on the performance of the entire exhaust system.

[0016] In some embodiments, the extension direction of the outlet is consistent with the flow direction of the gas after it leaves the spiral channel.

[0017] In the technical solution of this application embodiment, by aligning the exhaust duct direction with the gas outflow direction, the severe turbulence, impact, and resulting dynamic pressure loss caused by abrupt changes in gas flow direction at the outlet are eliminated. The kinetic energy of the gas flow is preserved, making the exhaust process extremely smooth, reducing the flow resistance of the entire exhaust system, and improving peak exhaust efficiency. The smooth transition of flow direction avoids the generation of local low-pressure zones or dead zones at the exhaust duct inlet. This reduces the possibility of energy dissipation due to turbulence and prevents the deposition and accumulation of fine impurities separated by centrifugal force at the inlet corner, thereby reducing the risk of local blockage of the exhaust duct and ensuring long-term operational stability. The rotational kinetic energy and directionality gained by the gas in the spiral flow channel are continued when entering the exhaust duct. This orderly flow state helps the gas maintain a high flow velocity and stability in the exhaust duct, making the exhaust process more controllable and efficient.

[0018] In some embodiments, the diameter of the air outlet gradually decreases from the end closest to the exhaust chamber to the end furthest from the exhaust chamber.

[0019] In the technical solution of this application embodiment, the tapered structure of the exhaust duct actively accelerates the gas, enabling it to be discharged at a higher speed and improving instantaneous exhaust capacity. This acceleration creates a local low pressure in the necking region. This low-pressure area exerts a suction effect (i.e., Venturi effect) on the upstream (i.e., the exhaust chamber and the spiral flow channel), not only promoting the overall gas flow but also effectively suppressing the backflow of external air or discharged gas into the molding cavity due to pressure difference at the moment of injection completion and pressure drop in the molding cavity. This avoids oxidation or secondary porosity on the casting surface that may be caused by gas backflow. The continuous acceleration of the gas in the exhaust duct increases its ability to carry extremely small amounts of fine impurities that may enter with the airflow, making it more difficult for them to deposit on the pipe wall and helping to maintain the long-term unobstructed flow of the exhaust duct. The gas is ejected at a higher speed at the outlet, with greater kinetic energy, which can more effectively overcome any external resistance.

[0020] In some embodiments, the mold body is further provided with an overflow well, which is connected to the molding cavity through a flow channel; part of the flow channel is opened on the inner wall of the guide groove and is closed by the structural surface of the slider.

[0021] In the technical solution of this application embodiment, compared with drilling deep, long, and tortuous overflow holes inside the mold body, the process of machining open grooves on the inner wall of the guide channel is simpler and less costly. Simultaneously, the flow channel wall formed by the slider structural surface is flat and smooth, which facilitates the smooth flow of the molding liquid and reduces flow resistance and the risk of air entrapment caused by rough internal flow channel surfaces or machining steps. During mold opening, the core-pulling movement of the slider causes relative sliding between its structural surface and the guide channel groove. This mechanical action effectively scrapes and cleans any trace metal residue or paint carbon deposits that may adhere to the groove, achieving a certain degree of self-cleaning function for this section of the flow channel and reducing maintenance frequency and difficulty.

[0022] In some embodiments, the opening at the end of the exhaust duct away from the exhaust chamber is connected to the flow channel, and the exhaust duct only allows gas to pass through.

[0023] In the technical solution of this application embodiment, during the pressure holding stage, the high-pressure molding fluid in the flow channel automatically forms a physical seal against the exhaust outlet, causing the exhaust system to automatically shut down during the metal feeding stage, preventing pressure leakage through the exhaust system, ensuring the pressure holding effect, and eliminating the risk of backflow of gas under pressure changes. The gas discharged by the exhaust system during the filling stage provides a buffer for overflow, making the flow of cold-stained molding fluid smoother and the removal of impurities more effective. After entering the pressure holding stage, the high pressure in the flow channel sealing the exhaust outlet also prevents the molding fluid from back-seeping into the exhaust channel and exhaust chamber.

[0024] In some embodiments, the venting area is fixed to the slider in an embedded manner.

[0025] In the technical solution of this application embodiment, a specially prepared sintered metal block is used as the venting zone for embedding. Its porous structure parameters (such as pore size distribution, porosity, and air permeability) can be independently optimized to obtain the best venting efficiency and resistance to molding liquid penetration. Simultaneously, sintered metal materials typically possess excellent thermal shock resistance and high-temperature strength, resulting in a longer service life. When the embedded venting zone experiences performance degradation due to long-term use or accidental damage, it can be relatively easily removed from the slider's groove and replaced with a new sintered metal block. This modular design makes maintenance quick and economical, and allows for upgrades to venting performance (e.g., replacing with sintered metal with a more advanced pore structure) without replacing the entire slider.

[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the external structure of a die-casting mold for robot joint parts provided in some embodiments of this application; Figure 2 A cross-sectional view of a die-casting mold for robot joint parts provided in some embodiments of this application; Figure 3 This is a partial structural schematic diagram of a die-casting mold for robot joint parts provided in some embodiments of this application; Figure 4 This is a schematic diagram of the slider structure provided in some embodiments of this application; Figure 5 A partial cross-sectional view of a slider provided in some embodiments of this application; Figure 6 A cross-sectional view of a slider provided in other embodiments of this application; Figure 7 A cross-sectional view of a slider provided in some embodiments of this application; Figure 8 for Figure 3 Enlarged view of point A in the middle.

[0029] Icons: 1-Mold body; 10-Molding cavity; 11-Guide groove; 12-Overflow well; 13-Flow channel; 2-Slider; 20-Working surface; 200-Exhaust zone; 21-Structural surface; 22-Exhaust channel; 23-Exhaust chamber; 230-Guide wall; 231-Spiral flow channel; 24-Air outlet. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0032] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0035] In this application, "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0036] According to some embodiments of this application, optionally, such as Figures 1-6 As shown, this application provides a die-casting mold for robot joint parts. The die-casting mold for robot joint parts includes a mold body 1 and a slider 2. The mold body 1 has a molding cavity 10 for molding products inside, and the mold body 1 also has a plurality of guide grooves 11 communicating with the molding cavity 10. The slider 2 is disposed in the guide grooves 11. The slider 2 includes a structural surface 21 and a working surface 20 that fits with the inner wall surface of the molding cavity 10. Among them, an exhaust zone 200 is provided in the edge area where the working surface 20 fits with the molding cavity 10. The exhaust zone 200 is made of sintered metal that only allows gas to pass through. The slider 2 also has a plurality of exhaust channels 22 that extend to the structural surface 21 and are used to discharge the gas passing through the exhaust zone 200.

[0037] Die casting is a process that uses high pressure to inject molding fluid into the forming cavity of a mold to quickly form complex metal parts. The specific process is divided into four steps: mold closing, injection, pressure holding and solidification, and mold opening and part removal.

[0038] The molding cavity 10 is the core space in the die-casting mold that directly shapes the final part. The molding liquid fills this space under high pressure and solidifies, ultimately forming a part that is completely identical to the molding cavity 10.

[0039] Multi-directional core pulling is a core demolding technology used in die casting, injection molding and other mold forming processes for parts with complex lateral concave and convex structures, holes and undercuts. Its core purpose is to use multiple independently movable sliders 2 to first pull away the mold components with lateral structures of the molded casting during the demolding stage, eliminate the interference between the casting and the mold, and then eject the casting.

[0040] Sintered metal refers to metal materials or products made from metal powder or a mixture of metal powder and non-metal powder as raw materials, through molding, sintering and subsequent processing. It has uniform, interconnected micron-sized pores inside, allowing gas to pass through at high speed, but effectively blocking the penetration of molding liquid (the surface can be treated with a metal-repellent coating).

[0041] The castings, workpieces, molded parts, and products mentioned in this application refer to robot joint parts processed by the molding die provided in this application.

[0042] In practical applications, special designs were implemented for edge areas (such as the root of the boss and the junction of the deep cavity sidewalls) where gas dead zones might form after the working surface 20 of the slider 2 and the forming cavity 10 are assembled. In these areas of the slider 2, venting zones 200 composed of porous sintered metal blocks are machined. The surface of the venting zone 200 is flush with the working surface 20 of the slider 2 to ensure that it does not affect the shape of the casting. Simultaneously, several small venting channels 22 are machined inside the slider 2. One end of these venting channels 22 connects to the back of the venting zone 200, and the other end extends to the structural surface 21 of the slider 2 (i.e., the non-forming surface that mates with the guide groove 11).

[0043] In actual die casting production, after the mold is closed, each slider 2 is positioned under the action of the drive mechanism, and its working surface 20 is tightly fitted with the forming cavity 10. When the high-temperature forming liquid fills the forming cavity 10 at high speed under high pressure, the air originally present in the forming cavity 10 and the gaps between the parts, as well as the gas generated by the coating, will be driven to the closed corners by the forming liquid flow. At this time, the venting zone 200 located at the edge of the parting begins to play its role: under pressure, the gas can pass through the tiny interconnecting pores inside the sintered metal and enter the space on its back side. However, the forming liquid, due to its surface tension and viscosity being much greater than that of the gas, and its pore size being much smaller than its grain size, is blocked outside the sintered metal and cannot penetrate. The gas passing through the venting zone 200 then enters the venting channel 22 inside the slider 2 and is discharged from the structural surface 21 along the venting channel 22. These gases can eventually be guided to the atmosphere outside the mold. After the casting has cooled and solidified, the mold is opened and the slider 2 is driven to pull the core, and the formed casting can be removed.

[0044] The molding die provided in this application directly sets the venting point in the venting zone 200 at the edge of the slider 2 where gas is most likely to accumulate, achieving venting at the source. The gas venting path is short and efficient, reducing or even eliminating defects such as porosity, undercasting, and surface flow marks caused by gas retention in castings. This improves the internal density, mechanical properties, and surface quality of high-requirement structural components such as robot joint parts. The venting zone 200, composed of sintered metal, has a microporous structure that acts as a filter, reliably blocking high-pressure molding fluid while allowing gas to pass through. This solves the problem of metal flash and blockage failure that easily occur when directly opening venting holes in the joint area, ensuring the long-term effectiveness of the venting structure. The venting zone 200 is cleverly integrated into the slider 2, independent of the main parting surface, and is suitable for die-casting molds with multi-directional core pulling and complex shapes (such as robot joint part molds). It enhances the process stability and molding reliability of the mold when die-casting complex structural products, improving the product yield.

[0045] In practice, the sintered metal of the exhaust zone 200 can be designed as a multi-layered composite structure with a gradient along the thickness direction. For example, a finer pore size can be used on the side near the working surface 20 to enhance the ability to block the molding liquid, while a larger pore size can be used on the side near the exhaust channel 22 to reduce airflow resistance, thereby further improving exhaust efficiency while ensuring that the molding liquid does not seep in.

[0046] According to some embodiments of this application, optionally, such as Figure 5 and Figure 7 As shown, the slider 2 is also provided with an exhaust chamber 23 and an exhaust duct 24 that connects the exhaust chamber 23 with the external space; the exhaust duct 22 connects to the exhaust chamber 23.

[0047] In practical applications, the high-speed filling molding fluid drives the gas to the joining edges of each slider 2. After passing through the sintered metal in the exhaust zone 200, the gas enters its respective exhaust channel 22 and flows along the exhaust channel 22, eventually all of it converging into the exhaust chamber 23. Subsequently, the gas gathered in the exhaust chamber 23 is efficiently and centrally discharged to the outside of the mold through the exhaust channel 24 under the action of pressure difference.

[0048] By converging multiple dispersed exhaust ducts 22 into a unified exhaust duct 24, the complexity of connecting the slider 2 to the outside of the mold is simplified. This makes external piping and sealing of the mold easier, improving the convenience of mold assembly and maintenance. The exhaust chamber 23, acting as a buffer and pressure equalization space, balances the airflow pressure from different exhaust ducts 22, resulting in more balanced and stable exhaust from each exhaust zone 200. Simultaneously, the concentrated gas is discharged through the potentially larger cross-sectional area of ​​the exhaust duct 24, reducing flow resistance and facilitating rapid and concentrated gas discharge at critical moments, further improving exhaust efficiency.

[0049] According to some embodiments of this application, optionally, such as Figure 7 As shown, the exhaust chamber 23 is provided with a guide wall 230, which spirals from the inside to the outside to form a spiral flow channel 231. The inlet of the spiral flow channel 231 is connected to the outlet of the exhaust channel 22.

[0050] In practical applications, the gas from each exhaust duct 22 is designed to exit directly tangentially to the inlet of the spiral flow channel 231. At the moment of die-casting filling, the high-temperature, high-pressure gas flows into the exhaust chamber 23 from multiple exhaust ducts 22. Instead of spreading and colliding randomly, it is guided and constrained by the wall of the spiral flow channel 231. The gas rotates and accelerates along a spiral path. After being organized and accelerated by the spiral flow channel 231, the gas orderly converges at the end of the flow channel 13, i.e., the center of the exhaust chamber 23 or the area near the inlet of the outlet duct 24, and finally is smoothly and centrally discharged through the outlet duct 24.

[0051] The spiral flow channel 231 provides forced guidance for gas flow, integrating potentially turbulent and opposing airflows into a single, orderly, forward-rotating flow. This significantly reduces flow resistance and pressure loss within the exhaust chamber 23, achieving faster and smoother centralized exhaust. The spiral-forward airflow pattern creates a certain directional inertia, helping to suppress weak reverse gas flow (backflow) that may occur during injection pressure fluctuations or molding liquid solidification and shrinkage, ensuring unidirectional stability of the exhaust and avoiding surface defects in the casting that may result from airflow disturbances.

[0052] In the specific implementation process, the inlet section of the spiral channel 231 adopts a larger cross-sectional area and a smaller pitch to quickly receive and stabilize the airflow; the middle section reduces the cross-sectional area to increase the flow velocity and centrifugal force, thereby enhancing the separation effect; the outlet section further expands the cross-sectional area to reduce the flow velocity and smoothly introduce the air into the outlet channel 24.

[0053] According to some embodiments of this application, optionally, such as Figure 5 and Figure 7 As shown, the exhaust chamber 23 has a columnar structure; the central axis of the spiral flow channel 231 coincides with the central axis of the exhaust chamber 23; the exhaust duct 24 is connected to the circumferential inner wall of the exhaust chamber 23; the spiral flow channel 231 is configured to guide the gas entering from its central inlet along a spiral trajectory to the exhaust duct 24 at the circumferential inner wall of the exhaust chamber 23.

[0054] In practical applications, the gas collected from each exhaust channel 22 enters through the inlet of the central spiral flow channel 231. Subsequently, constrained by the guide wall 230, the gas moves in a spiral motion from the central region outwards. The gas finally flows to the inlet of the exhaust channel 24 located on the circumferential inner wall. The accelerated gas smoothly enters the exhaust channel 24 here and is finally discharged from the mold.

[0055] The combination of the columnar structure and the coaxial spiral flow channel 231 makes the airflow organization orderly and predictable. This design can effectively avoid local eddies and dead zones, making the pressure loss (pressure drop) calculation along the entire exhaust path more accurate and the operating state more stable.

[0056] According to some embodiments of this application, optionally, such as Figure 7 As shown, multiple air outlets 24 are evenly arranged along the circumferential inner wall of the exhaust chamber 23.

[0057] The number of air outlets 24 can be two, three, four, five, six, seven, eight, nine, ten or more.

[0058] In practical applications, the gas flowing outward from the center along the spiral channel 231 will no longer have only a single outlet option when it reaches the end of the channel 13 and the area near the periphery of the exhaust chamber 23. Instead, it can be discharged outward simultaneously and evenly through multiple outlet channels 24. This design changes the final gas discharge path from a single-point outlet to a multi-point distributed outlet.

[0059] Multiple exhaust ducts 24 provide a larger total exhaust outlet cross-sectional area, reducing the flow resistance of gas in the final exhaust stage. At critical moments of high-speed filling of the molding liquid and instantaneous large-volume gas generation, the system can exhaust gas with lower back pressure and faster speed, enhancing its exhaust capability to handle injection peaks and reducing the risk of defects due to insufficient instantaneous exhaust. The uniformly arranged exhaust ducts 24 ensure that gas is evenly drawn away from the outer periphery of the spiral flow channel 231, avoiding airflow asymmetry or local turbulence that may result from unilateral extraction. Simultaneously, the multiple outlets constitute a simple redundant system. Even if the flow capacity of individual exhaust ducts 24 temporarily decreases due to external unforeseen circumstances (such as slight obstruction by foreign objects), the remaining exhaust ducts 24 can still ensure continuous effective exhaust function, significantly improving the operational reliability and robustness of the exhaust system. Distributing the exhaust load across multiple outlets avoids the concentrated impact of large-volume gas on a single exhaust duct 24, which helps extend the service life of these components. It also reduces the impact of machining errors or minor blockages at a single outlet on the overall performance of the exhaust system.

[0060] According to some embodiments of this application, optionally, such as Figure 7 As shown, the extension direction of the gas outlet 24 is consistent with the flow direction of the gas after it leaves the spiral flow channel 231.

[0061] In practical applications, since the gas moves outward along a spiral trajectory within the spiral channel 231, when it reaches the end of the channel 13 and is located on the periphery of the exhaust chamber 23, its velocity direction is tangential to the spiral at that point. Therefore, the central axis of the exhaust duct 24, which connects to this location, also extends outward along the same tangential direction. This means that after the gas flows out of the rotating spiral channel 231, it can flow naturally and smoothly into the exhaust duct 24 without changing direction or with only a very small directional adjustment, and continue to be discharged outward along that direction.

[0062] This application eliminates the severe turbulence, impact, and resulting dynamic pressure loss caused by abrupt changes in gas flow direction at the outlet by aligning the direction of the exhaust duct 24 with the gas outflow direction. The kinetic energy of the gas flow is preserved, resulting in an extremely smooth exhaust process, reducing the flow resistance of the entire exhaust system, and improving peak exhaust efficiency. The smooth transition of flow direction avoids the formation of local low-pressure zones or dead zones at the inlet of the exhaust duct 24. This reduces the possibility of energy dissipation due to turbulence and prevents the deposition and accumulation of fine impurities separated by centrifugal force at the inlet corner, thereby reducing the risk of local blockage of the exhaust duct 24 and ensuring long-term operational stability. The rotational kinetic energy and directionality gained by the gas in the spiral flow channel 231 are continued when entering the exhaust duct 24. This orderly flow state helps the gas maintain a high flow velocity and stability in the exhaust duct 24, making the exhaust process more controllable and efficient.

[0063] According to some embodiments of this application, optionally, such as Figure 7 As shown, the diameter of the air outlet 24 gradually decreases from the end closest to the exhaust chamber 23 to the end furthest from the exhaust chamber 23.

[0064] In practical applications, the exhaust duct 24 has a larger diameter at the end near the exhaust chamber 23 (i.e., the inlet end), and then its inner wall tapers smoothly towards the end away from the exhaust chamber 23 (i.e., the outlet end), making the diameter of the outlet end smaller than that of the inlet end. Gas flowing out from the end of the spiral flow channel 231 first enters the relatively wide inlet end of the exhaust duct 24. Subsequently, as the gas flows forward, due to the gradually decreasing cross-sectional area of ​​the channel, its velocity gradually increases according to fluid dynamics principles, while the static pressure decreases accordingly.

[0065] The tapering structure of the exhaust duct 24 actively accelerates the gas, allowing it to exit at a higher speed and improving instantaneous exhaust capacity. This acceleration creates a localized low pressure in the constricted area. This low-pressure zone exerts a suction effect on the upstream (i.e., exhaust chamber 23 and spiral flow channel 231) (i.e., the Venturi effect), not only promoting overall gas flow but also effectively suppressing the backflow of external air or discharged gas into the forming cavity 10 due to pressure difference at the moment of pressure drop after injection, thus avoiding oxidation or secondary porosity on the casting surface that may be caused by gas backflow. The continuous acceleration of the gas within the exhaust duct 24 increases its ability to carry extremely small amounts of impurities that may enter with the airflow, making it more difficult for them to deposit on the pipe wall and helping to maintain the long-term unobstructed flow of the exhaust duct 24. The gas is ejected at a higher speed at the outlet, with greater kinetic energy, which can more effectively overcome any external resistance.

[0066] According to some embodiments of this application, optionally, such as Figures 2-3As shown, the mold body 1 is also provided with an overflow well 12, which is connected to the molding cavity 10 through a flow channel 13; part of the flow channel 13 is opened on the inner wall of the guide groove 11 and is closed by the structural surface 21 of the slider 2.

[0067] In practical applications, in addition to the aforementioned venting system, the mold body 1 is also equipped with an overflow well 12 (also known as an overflow channel). The overflow well 12 is usually located at the edge of the mold parting surface or a specific position, and is used to contain residual material containing gas, oxide scale, and cold metal at the end of die casting. The overflow well 12 is connected to the end of the forming cavity 10 or an area prone to cold shut-off through the flow channel 13. Part of the path of the flow channel 13 is not entirely opened in the fixed part of the mold body 1, but utilizes the mating interface between the slider 2 and the mold body 1. Specifically, a U-shaped or semi-circular groove is machined on the inner wall of the guide groove 11. When the slider 2 is assembled in place, its structural surface 21 (i.e., the non-forming side that mates with the guide groove 11) fits tightly with this groove on the inner wall of the guide groove 11, together forming a complete and closed flow channel 13 cross section. This flow channel 13, which is composed of two parts, is connected to the forming cavity 10 at one end and leads to the overflow well 12 located in the fixed part of the mold at the other end. During die casting, after the high-speed filling of the molding fluid fills the molding cavity 10, excess cold material and entrained gas, under the continuous action of injection pressure, will enter the runner 13 from the molding cavity 10. The molding fluid flows along the runner 13 and eventually enters the overflow well 12. Since this runner 13 is partially closed by the structural surface 21 of the slider 2, when die casting is completed, the mold is opened, and the slider 2 is driven to perform the core-pulling movement, the structural surface 21 of the slider 2 will move along the groove on the inner wall of the guide groove 11. This relative movement helps to automatically peel off and remove any small amount of metal flash or residue that may adhere to the groove, so that this section of the runner 13 remains unobstructed when the mold is closed.

[0068] Compared to drilling deep, long, and tortuous overflow holes inside the mold body 1, machining open grooves on the inner wall of the guide channel 11 is a simpler and less costly process. Simultaneously, the smooth and flat wall of the flow channel 13, formed by the structural surface 21 of the slider 2, facilitates smooth flow of the molding liquid, reducing flow resistance and the risk of air entrapment caused by rough surfaces or machining steps in the internal flow channel 13. During mold opening, the core-pulling movement of the slider 2 causes relative sliding between its structural surface 21 and the groove of the guide channel 11. This mechanical action effectively scrapes and cleans any trace metal residue or paint carbon deposits that may adhere to the groove, achieving a certain degree of self-cleaning function for this section of the flow channel 13, reducing maintenance frequency and difficulty.

[0069] According to some embodiments of this application, optionally, such as Figure 3 and Figure 8 As shown, the opening of the exhaust duct 24 at the end away from the exhaust chamber 23 is connected to the flow channel 13, and the exhaust duct 22 only allows gas to pass through.

[0070] During high-speed filling, the gas in the molding cavity 10 is driven by the molding liquid, flows through the venting zone 200, through the venting channel 22 and the venting chamber 23, and is finally accelerated out of the outlet channel 24 into the flow channel 13. This initially discharged gas partially fills the flow channel 13 and the overflow well 12, creating a buffer space for subsequent cold molding liquid overflow. When the molding cavity 10 is completely filled and the press enters the pressure holding stage, the continuous high pressure causes the molding liquid containing cold material to completely fill and compact the overflow well 12 and its connected flow channel 13. At this time, the molding liquid pressure in the flow channel 13 rapidly increases and stabilizes at a very high value. This high pressure acts in reverse on the outlet of the outlet channel 24. Because the sintered metal in the exhaust zone 200 only allows gas to pass through, it effectively prevents the molding liquid from invading in the reverse direction. Furthermore, the outlet of the exhaust channel 24 is blocked by the high-pressure molding liquid. This effectively isolates the entire exhaust passage (exhaust channel 22, exhaust chamber 23, and exhaust channel 24) during the pressure holding stage, maintaining it in a relatively closed, pressure-balanced state. It neither continues to draw gas from the molding chamber 10 nor exhausts gas into the flow channel 13, entering a quiescent, stable state. This state continues until the metal solidifies and the pressure is released.

[0071] During the pressure holding stage, the high-pressure molding fluid in flow channel 13 automatically forms a physical seal against the outlet of exhaust channel 22, causing the exhaust system to automatically shut down during the metal feeding stage, preventing pressure leakage through the exhaust system, ensuring the pressure holding effect, and eliminating the risk of backflow of gas under pressure changes. The gas discharged by the exhaust system during the filling stage provides a buffer for overflow, making the flow of cold molded fluid smoother and the removal of impurities more effective. After entering the pressure holding stage, the high pressure of flow channel 13 sealing off the exhaust channel 24 also prevents the molding fluid from back-seeping into the exhaust channel 22 and the exhaust chamber 23.

[0072] According to some embodiments of this application, optionally, such as Figure 6 As shown, the exhaust zone 200 is fixed to the slider 2 by means of embedding.

[0073] In practical applications, a groove or mounting base is first machined at a predetermined position on the working surface 20 of the slider 2 (usually at the edge or corner where gas is expected to accumulate after assembly with the molding cavity 10). Then, a pre-sintered metal block with specified porosity and shape is firmly embedded and fixed into this groove using methods such as interference fit, brazing, or the use of high-strength threaded fasteners resistant to high temperatures. After embedding, the mating surfaces need to be treated to ensure that the surface of the sintered metal block is flush and smooth with the working surface 20 of the slider 2, together forming a continuous surface of the molding cavity 10 (i.e., the working surface 20). When the molding liquid impacts the assembly area of ​​the slider 2, the gas is driven to this location and rapidly discharged through the embedded sintered metal block. Because this exhaust zone 200 is embedded as an independent prefabricated component, its material properties (such as porosity, pore size, and heat resistance) and structural shape can be optimally designed and guaranteed, without being limited by the processing performance of the slider 2 base material (usually mold steel).

[0074] This application employs a specially prepared sintered metal block as the venting zone 200, which allows for independent optimization of its porous structure parameters (such as pore size distribution, porosity, and permeability) to achieve optimal venting efficiency and resistance to molding liquid penetration. Furthermore, sintered metal materials typically possess excellent thermal shock resistance and high-temperature strength, resulting in a longer service life. When the venting zone 200 experiences performance degradation due to long-term use or accidental damage, it can be relatively easily removed from the groove of the slider 2 and replaced with a new sintered metal block. This modular design enables quick and economical maintenance and allows for upgrades to venting performance (e.g., replacing with a sintered metal with a more advanced pore structure) without replacing the entire slider 2.

[0075] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A die-casting mold for robot joint parts, characterized in that, include: The mold body has a molding cavity inside for molding products, and the mold body also has multiple guide grooves that connect to the molding cavity. A slider is disposed within the guide groove, and the slider includes a structural surface and a working surface that fits into the inner wall surface of the molding cavity; Wherein, an exhaust zone is provided in the edge area where the working surface and the forming cavity are joined, and the exhaust zone is made of sintered metal that only allows gas to pass through; The slider is also provided with multiple exhaust channels, which extend to the structural surface and are used to discharge gas passing through the exhaust zone.

2. The die-casting mold for robot joint parts according to claim 1, characterized in that, The slider also has an exhaust chamber and an air outlet connecting the exhaust chamber to the external space. The exhaust passage connects to the exhaust chamber.

3. The die-casting mold for robot joint parts according to claim 2, characterized in that, The exhaust chamber is provided with a guide wall, which spirals from the inside to the outside to form a spiral flow channel. The inlet of the spiral flow channel is connected to the outlet of the exhaust channel.

4. The die-casting mold for robot joint parts according to claim 3, characterized in that, The exhaust chamber has a columnar structure; The central axis of the spiral flow channel coincides with the central axis of the exhaust chamber; The air outlet is connected to the circumferential inner wall of the exhaust chamber; The spiral flow channel is configured to guide gas entering from its central inlet along a spiral trajectory toward the outlet channel on the circumferential inner wall of the exhaust chamber.

5. A die-casting mold for robot joint parts according to claim 4, characterized in that, The plurality of air outlets are evenly arranged along the circumferential inner wall of the exhaust chamber.

6. The die-casting mold for robot joint parts according to claim 4, characterized in that, The extension direction of the gas outlet is consistent with the flow direction of the gas after it leaves the spiral channel.

7. The die-casting mold for robot joint parts according to claim 4, characterized in that, The diameter of the air outlet gradually decreases from the end closest to the exhaust chamber to the end furthest from the exhaust chamber.

8. The die-casting mold for robot joint parts according to claim 2, characterized in that, The mold body is also provided with an overflow well, which is connected to the molding cavity through a flow channel; Part of the flow channel is formed on the inner wall of the guide groove and is closed by the structural surface of the slider.

9. A die-casting mold for robot joint parts according to claim 8, characterized in that, The opening at the end of the exhaust duct away from the exhaust chamber is connected to the flow channel, and the exhaust duct only allows gas to pass through.

10. A die-casting mold for robot joint parts according to claim 1, characterized in that, The exhaust zone is fixed to the slider in an embedded manner.

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