Center pouring gate die-casting forming die and method

Abstract

The invention relates to a center sprue die-casting forming die, and belongs to the technical field of die-casting forming. The center sprue die-casting forming mold comprises a first sub-mold, a second sub-mold, a mold core and a cross gate, wherein the first sub-mold and the second sub-mold are spliced to form a forming cavity for forming a forming part; the mold core comprises a shell and a movable body; the first sub-mold is provided with a mounting hole; the mold core extends into the forming cavity through the mounting hole; the transverse pouring gate is arranged on the side, away from the first sub-mold, of the second sub-mold, and the transverse pouring gate communicates with the forming cavity; the shell is used for making contact with a formed part. Part of the movable body is located inside the shell. The movable body is pulled by the first sub-mold during mold opening to be separated from the shell; the movable body is configured to beat the inner wall of the shell when the first sub-mold and the second sub-mold are opened, so that the shell drives the forming part to vibrate; and the forming piece vibrates to be separated from the shell and the inner wall of the forming cavity. The center sprue die-casting forming die provided by the embodiment of the invention can improve the yield of formed parts.

Description

Technical Field

[0001] This application relates to the field of die casting technology, and more specifically, to a center gate die casting mold. Background Technology

[0002] The top cover is an alloy die-cast product. Compared to ordinary die-cast parts, these products are characterized by thin walls and complex geometric structures. During the demolding process after die casting, these types of molded parts commonly suffer from adhesion between the molded part and the mold cavity and core. This adhesion is caused by the clamping force generated by material cooling and shrinkage, concentrated demolding resistance due to complex surfaces, deformation adhesion due to insufficient rigidity in thin-walled areas, and retention effects at mold surface textures or defects. Specifically, after the molded part leaves the mold, solidified material residue remains on the surface of the cavity or core; tearing burrs appear on the edges or grooves of the molded part; the inner wall of the deep cavity structure is stretched and deformed by the pulling resistance due to shrinkage and adhesion to the core; and thin-walled edges are adsorbed onto the mold cavity surface due to negative air pressure during ejection, forming depressions. These defects result in localized thinning of the molded part's wall thickness or changes in shape that are incompatible with the usage environment, affecting the yield rate of the molded part. Summary of the Invention

[0003] The purpose of this application is to address the above-mentioned problems by providing a center gate die casting mold that can improve the yield of molded parts and thus alleviate the aforementioned problems.

[0004] This application is achieved through the following technical solution: In a first aspect, this application provides a center-gated die-casting mold for manufacturing thin-walled molded parts. The center-gated die-casting mold includes a first sub-mold, a second sub-mold, a core, and a runner. The first and second sub-molds are assembled to form a molding cavity for molding the molded part. The core includes a shell and a movable body. The first sub-mold is provided with mounting holes. The core extends into the molding cavity through the mounting holes. The runner is located on the side of the second sub-mold opposite to the first sub-mold, and the runner communicates with the molding cavity. The shell is used to contact the molded part. Part of the movable body is located inside the shell. The movable body is pulled away from the shell by the first sub-mold when the mold is opened. The movable body is configured to strike the inner wall of the shell when the first and second sub-molds are opened, so that the shell causes the molded part to vibrate. The molded part vibrates to separate from the shell and the inner wall of the molding cavity.

[0005] In the technical solution of this application embodiment, during use, the first and second sub-molds are assembled. The core extends into the molding cavity through the mounting hole of the first sub-mold. The outer surface of the shell and the inner wall of the molding cavity together form the molding cavity contour for molding the part. The molding liquid is injected into the molding cavity through the horizontal runner on the side of the second sub-mold and fills the molding cavity through the center gate. The outer side of the shell is in direct contact with the molding liquid. The molding liquid cools and shrinks in the molding cavity and eventually hardens into the part. Then, the first and second sub-molds begin to open. The core shell moves with the first sub-mold. At this time, the part is still attached to the outer surface of the shell and the cavity wall of the second sub-mold due to the clamping force. With the mold opening action, the movable body is driven by the first sub-mold and moves relative to the shell. When the movable body separates from the shell to a preset gap, the movable body hits the inner wall of the shell, causing the shell to generate high-frequency micro-vibration. Then, the vibration of the shell is transmitted to the part through the contact interface, causing the part to start vibrating, breaking the adsorption and clamping forces between the part and the outer surface of the shell and the inner wall of the molding cavity. For the inner surface of the molded part, vibration disperses the extraction resistance between it and the shell; for the outer surface of the molded part, vibration eliminates the negative air pressure adsorption force between it and the inner wall of the molding cavity, ultimately separating the molded part from the shell and the cavity of the second mold, or separating it from the shell and the second mold with the assistance of ejector pins. The center gate die-casting mold provided in this application can cause the molded part to vibrate by the moving body hitting the shell when the mold opens, causing the molded part to separate from the shell and the inner wall of the molding cavity, thereby reducing the situation where the molded part is pulled by the molding cavity and core during demolding, resulting in local wall thickness reduction or shape change, and improving the yield of the molded part.

[0006] In some embodiments, the inner diameter of the shell gradually increases from the end near the runner to the end away from the runner; the movable body moves up and down relative to the shell along its own height length so that its outer surface is attached to or separated from the inner wall surface of the shell.

[0007] In the technical solution of this application embodiment, the inner diameter of the shell gradually increases from the end near the runner to the end away from the runner. Furthermore, the movable body is in contact with the inner wall of the shell before mold opening, and separates from the inner wall of the shell during mold opening. When the movable body is in contact with the inner wall of the shell, it can support the shell and share the shrinkage stress from the molded part, thereby reducing the risk of the shell deforming under the pressure of the molded part and affecting the shape of the molded part. During mold opening, the movable body first separates from the inner wall of the shell, allowing it to have room to move, and then swings to strike the shell.

[0008] In some embodiments, a set of first pushing parts is provided on each of the opposite sides of the inner wall of the housing; a set of first pushing parts includes a plurality of first pushing parts arranged sequentially along the length direction of the housing; the two sets of pushing parts located on opposite sides of the inner wall of the housing are staggered; a second pushing part is provided on each of the opposite sides of the outer wall of the movable body; when the movable body is opened, it moves relative to the housing along its own height length so that the second pushing part contacts the first pushing part; the two sets of first pushing parts alternately push the two second pushing parts so that the movable body moves back and forth along the line connecting the two sets of first pushing parts to pat the inner wall of the housing; the two second pushing parts correspond one-to-one with the two sets of first pushing parts.

[0009] In the technical solution of this application embodiment, during mold closing, multiple sets (at least two sets) of first pushing parts are arranged in an alternating pattern on both sides of the inner wall of the housing. The second pushing parts on both sides of the movable body are located in the initial position inside the housing. At this time, the second pushing parts contact the inclined surfaces of the first pushing parts, forming a pre-positioned fit. During mold opening, in the radial direction of the movable body (i.e., on the line connecting the two opposing sets of first pushing parts), the first parting mold drives the movable body to move in the mold opening direction, so that the second pushing parts and the inclined surfaces of the first pushing parts begin to contact. When one side of the second pushing part contacts the inclined surface of the first pushing part on the same side, the thrust generated by the mutual squeezing of the first and second pushing parts forces the movable body to swing to the other side. Then, after the movable body continues to move a certain distance under the drive of the first parting mold, the second pushing part on the other side contacts the inclined surface of the first pushing part on the same side. The thrust generated by the mutual squeezing of the first and second pushing parts on this side forces the movable body to swing to the forward side, thereby making the movable body reciprocate between the opposing sets of first pushing parts. When the moving body swings back and forth, its outer wall and the inner wall of the shell collide periodically, causing the shell to vibrate laterally. The vibration energy is transmitted to the molded part through the shell, destroying the bonding interface at the complex surface.

[0010] In some embodiments, the inner wall of the housing is further provided with a guide groove; the guide groove extends spirally along the length direction of the housing; the second pushing part is adapted to the guide groove; the second pushing part is farther away from the horizontal runner than the first pushing part.

[0011] In the technical solution of this application embodiment, when the mold is opened, the movable body first strikes the inner wall of the shell under the push of the first pusher, and then moves into the guide groove. The movable body continues to move and rotates relative to the shell under the constraint of the guide groove, so that the movable body can transmit the residual vibration energy to the shell along the spiral path, thereby improving the separation effect between the shell and the molded part.

[0012] In some embodiments, there are two guide slots, and each guide slot corresponds to one of the two second pushing parts. In the technical solution of this application embodiment, when the movable body rotates under the guidance of the guide groove of the shell, the spiral trajectory of the second push part on both sides is strictly symmetrical to avoid the movable body from deflecting; furthermore, the vibration kinetic energy of the movable body can be transmitted to the stacked guide groove through the symmetrical second push part, and the vibration energy is transmitted to the shell in a symmetrical mode to form a uniform ring vibration around the central axis, which can generate a balanced demolding force on the circumference of the shell.

[0013] In some embodiments, a protruding limiting ring is provided on the inner wall of the end of the housing opposite to the horizontal runner; the minimum distance between the limiting ring and the outer surface of the movable body is less than the size of the second pushing part extending beyond the outer surface of the movable body.

[0014] In the technical solution of this application embodiment, a protruding limiting ring is provided on the inner wall of the end of the shell away from the horizontal runner. When the mold is opened, the movable body is pulled and moved by the first parting mold and hits the inner wall of the shell for a period of time. Then, the second pushing part of the movable body contacts the limiting ring. Then, the second pushing part pulls the shell through the limiting ring to separate the shell from the molded part, so that the shell can leave the molded part together with the first parting mold. This eliminates the trouble of separating the shell from the molded part separately later and simplifies the use steps of the center gate die casting mold provided in this application.

[0015] In some embodiments, the movable body includes a first segment and a second segment along its length; the first segment is located inside the shell; the second segment is farther away from the runner than the first segment; the diameter of the second segment is larger than the diameter of the first segment; a first stepped surface is formed between the first segment and the second segment; the first stepped surface is used to contact the end face of the shell that is farther away from the runner.

[0016] In the technical solution of this application embodiment, the first segment of the movable body is completely inserted into the inner cavity of the shell, and the first stepped surface of the second segment is tightly fitted with the end face of the shell away from the horizontal runner, forming a sealed interface to prevent the alloy liquid from seeping in. Before mold opening, the first stepped surface is tightly fitted with the end face of the shell away from the horizontal runner, and the outer surface of the first segment is fitted with the inner wall of the shell. When the shell is subjected to pressure from the molded part, the first segment and the first stepped surface can share and support the force on the shell, thereby reducing the risk of deformation of the shell under the extrusion of the molded part. The second segment has a larger diameter, which enhances the vibration effect as a vibrating mass block, reducing the demolding resistance at the bottom of the inner cavity of the molded part, making it easier for the shell to separate from the molded part.

[0017] In some embodiments, the mounting hole includes a first hole segment and a second hole segment; the first hole segment is closer to the second parting mold than the second hole segment; the diameter of the second hole segment is larger than the diameter of the first hole segment; a portion of the housing is located inside the first hole segment; the outer wall of the housing contacts the inner wall of the first hole segment; the movable body also includes a third segment; the third segment is disposed on the side of the second segment away from the first segment; the third segment is located in the second hole segment, and the diameter of the third segment is larger than the diameter of the first hole segment; the second segment is located inside the first hole segment, and there is a gap between the second segment and the first hole segment.

[0018] In the technical solution of this application embodiment, the outer wall of the shell contacts the inner wall of the first hole segment, and the position of the shell is determined by the hole wall of the mounting hole to avoid the position of the shell located in the molding cavity deviating from the center of the molding cavity; there is a gap between the second segment and the first hole segment, allowing the movable body to move radially along the first hole segment inside the first hole segment to strike the inner wall of the shell; the diameter of the third segment is larger than the hole diameter of the first hole segment, allowing the third segment to stay in the second hole segment, thereby being pulled apart from the shell by the second mold.

[0019] In some embodiments, a second stepped surface is formed between the first hole segment and the second hole segment; the third segment contacts the second stepped surface.

[0020] In the technical solution of this application embodiment, when the core is inserted into the first mold, the movable body moves synchronously with the shell, pushing the shell into the molding cavity. The movable body moves to contact the second step surface. The position of the second step surface determines the size of the core extending into the molding cavity as a whole, so that the inner cavity shape of the molded part can meet the rated requirements.

[0021] Secondly, this application provides a center-gate die-casting molding method, which uses the center-gate die-casting molding mold of the first aspect, including the following steps: Step S100: preheating and closing the first mold, the second mold, and the core; Step S200: injecting molding liquid into the molding cavity, and then holding pressure, compensating for shrinkage, and cooling to obtain the molded part; Step S300: separating the first mold and the second mold, thereby causing the movable body to strike the shell, and then separating the molded part from the shell; Step S400: separating the molded part from the second mold and the runner.

[0022] In the technical solution of this application embodiment, in step S100, the first mold, the second mold, and the core are preheated in a gradient manner. The preheating temperature of the first mold and the second mold is higher than that of the core, thereby reducing the risk of the molding liquid cooling before the filling is completed. In step S200, the molding liquid is injected through the horizontal runner on the side of the second mold. The geometry of the molded part is targeted by staged injection (low-speed filling in the front section and high-speed compaction in the back section) to reduce flow defects. After the injection is completed, the molding cavity is immediately subjected to holding pressure, and then the shrinkage is continuously compensated through the horizontal runner to eliminate shrinkage cavities at the bottom of the deep cavity and the root of the boss. Finally, the mold and the molded part inside are cooled. In step S300, the first mold and the second mold are opened, driving the movable body to move away from the horizontal runner. After the movable body is pulled, it begins to pat the inner wall of the shell. The clamping force between the inner wall of the molded part and the shell is broken, causing the molded part to vibrate under the influence of the shell. This vibration weakens the adhesion and mechanical engagement between the molded part and the mold surface, facilitating subsequent demolding and separation of the molded part from the shell. In step S400, the molded part is further separated by an ejector system after vibration: a central ejector pin is used on the inner wall of the molded part, and a ring-shaped ejector pin is used on the outer edge of the molded part, working together to prevent deformation. The horizontal sprue is connected to the molded part through a cold slug well, automatically breaking off during ejection. The center-gate die-casting method provided in this application weakens the connection between the molded part and the core and the inner wall of the molding cavity before separation, thereby solving the problem of demolding adhesion for geometrically complex thin-walled molded parts and improving the yield rate of the molded parts.

[0023] 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

[0024] 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.

[0025] Figure 1 This is a schematic diagram of the overall structure of a center gate die-casting mold provided in some embodiments of this application; Figure 2 A top view of a center gate die-casting mold provided in some embodiments of this application; Figure 3 for Figure 2 Sectional view at point AA; Figure 4 for Figure 3 Enlarged view of point B in the middle; Figure 5 A cross-sectional view of the core when the movable body is attached to the housing according to some embodiments of this application; Figure 6 A cross-sectional view of the core when the moving body is separated from the shell, as provided in some embodiments of this application; Figure 7 Schematic diagrams of the housing structure provided for some embodiments of this application; Figure 8 Cross-sectional views of the housing provided for some embodiments of this application; Figure 9 A flowchart of a center gate die casting method provided for some embodiments of this application.

[0026] Icons: 1-Molded part; 2-First mold section; 20-Mounting hole; 200-First hole section; 201-Second hole section; 3-Second mold section; 4-Core; 40-Shell; 400-First pushing part; 401-Guide groove; 41-Moving body; 410-Second pushing part; 411-First section; 412-Second section; 413-Third section; 5-Gateway. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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 throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. 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.

[0030] 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.

[0031] 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.

[0032] 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).

[0033] According to some embodiments of this application, optionally, such as Figures 1-6 As shown, this application provides a center-gated die-casting mold for manufacturing a thin-walled molded part 1. The center-gated die-casting mold includes a first sub-mold 2, a second sub-mold 3, a core 4, and a runner 5. The first sub-mold 2 and the second sub-mold 3 are assembled to form a molding cavity for molding the molded part 1. The core 4 includes a shell 40 and a movable body 41. The first sub-mold 2 is provided with a mounting hole 20. The core 4 extends into the molding cavity through the mounting hole 20. The runner 5 is provided on the side of the second sub-mold 3 opposite to the first sub-mold 2, and the runner 5 communicates with the molding cavity. The shell 40 is used to contact the molded part 1. Part of the movable body 41 is located inside the shell 40. The movable body 41 is pulled away from the shell 40 by the first sub-mold 2 when the mold is opened. The movable body 41 is configured to strike the inner wall of the shell 40 when the first sub-mold 2 and the second sub-mold 3 are opened, so that the shell 40 drives the molded part 1 to vibrate. The molded part 1 vibrates to separate from the shell 40 and the inner wall of the molding cavity.

[0034] An elastic element or elastic layer can be provided between the shell 40 and the movable body 41 to make the force of the movable body 41 hitting the shell 40 more gentle when the mold is opened, thereby reducing the risk of the movable body 41 damaging the shell 40 during the hitting process.

[0035] The center gate die casting mold provided in this application can also be applied to the molding mold of the molded part 1 with thick walls but complex internal structure. This application takes the molded part 1 with thin walls and complex geometry as an example for description.

[0036] Mounting hole 20 extends from the molding cavity to the outer surface of the first mold 2, facilitating the insertion of core 4 into the cavity.

[0037] Center gate die casting refers to a forming method in which the gate (the entrance for molten metal to enter the cavity) is located at the center of the casting, and the molten metal radiates outward from the gate to fill the cavity.

[0038] This application manufactures thin-walled and geometrically complex molded parts 1 (e.g., top covers) by center gate die casting, which solves the problems of defects such as porosity and shrinkage at the far end of the ingate and difficulties in filling the mold in the subsequent processing of conventional molding methods that use an ingate set on the side wall of the molding cavity.

[0039] During use, the first mold 2 and the second mold 3 are assembled. The core 4 extends into the molding cavity through the mounting hole 20 of the first mold 2. The outer surface of the shell 40 and the inner wall of the molding cavity together form the molding cavity outline for molding the part 1. The molding liquid is injected into the molding cavity through the horizontal runner 5 on the side of the second mold 3 and fills the molding cavity through the center gate. The outer side of the shell 40 is in direct contact with the molding liquid. The molding liquid cools and shrinks in the molding cavity and eventually hardens into the part 1. Then, the first mold 2 and the second mold 3 begin to open. The core 4 and the shell 40 move with the first mold 2. At this time, the part 1 is still attached to the outer surface of the shell 40 and the cavity wall of the second mold 3 due to the clamping force. With the mold opening action, the movable body 41 is driven by the first mold 2 and moves relative to the shell 40. When the movable body 41 separates from the shell 40 to the preset gap, the movable body 41 hits the inner wall of the shell 40, causing the shell 40 to generate high-frequency micro-vibration. Then, the vibration of the housing 40 is transmitted to the molded part 1 through the contact interface, causing the molded part 1 to vibrate, thereby breaking the adsorption and clamping forces between the molded part 1 and the outer surface of the housing 40 and the inner wall of the molding cavity. For the inner surface of the molded part 1, the vibration disperses the extraction resistance between it and the housing 40; for the outer surface of the molded part 1, the vibration eliminates the negative air pressure adsorption force between it and the inner wall of the molding cavity. Finally, the molded part 1 separates from the housing 40 and the cavity of the second mold 3, or is separated from the housing 40 and the second mold 3 with the assistance of ejector pins. The center gate die casting mold provided in this application can cause the molded part 1 to vibrate by the moving body 41 hitting the housing 40 when the mold is opened, so that the molded part 1 separates from the housing 40 and the inner wall of the molding cavity, thereby reducing the situation where the molded part 1 is pulled by the molding cavity and the core 4 during demolding, resulting in local wall thickness reduction or shape change, and improving the yield of the molded part 1.

[0040] In some embodiments, a heating circuit can be provided inside the housing 40 to locally heat the surface of the housing 40 before demolding, thereby reducing the thermal shrinkage stress between the molded part 1 and the housing 40, and making it easier for the molded part 1 to separate from the core 4.

[0041] According to some embodiments of this application, optionally, such as Figures 5-6 and Figure 8 As shown, the inner diameter of the shell 40 gradually increases from the end near the runner 5 to the end away from the runner 5; the movable body 41 moves up and down relative to the shell 40 along its own height so that its outer surface is in contact with or separate from the inner wall of the shell 40.

[0042] The wall thickness of the shell 40 located in the molding cavity can be consistent at all points, so that the outer diameter and inner diameter of the part of the shell 40 located in the molding cavity gradually increase from the end near the horizontal runner 5 to the end away from the horizontal runner 5, so that the demolding resistance between the shell 40 and the molded part 1 is reduced compared with the straight cylindrical core 4.

[0043] The inner diameter of the shell 40 gradually increases from the end near the runner 5 to the end away from the runner 5. Before mold opening, the movable body 41 is in contact with the inner wall of the shell 40, but separates from it during mold opening. When the movable body 41 is in contact with the inner wall of the shell 40, it supports the shell 40 and shares the shrinkage stress from the molded part 1, thereby reducing the risk of deformation of the shell 40 under the pressure of the molded part 1, which could affect the shape of the molded part 1. During mold opening, the movable body 41 first separates from the inner wall of the shell 40, allowing it to move freely, and then swings to strike the shell 40.

[0044] According to some embodiments of this application, optionally, such as Figures 4-8 As shown, a set of first pushing parts 400 is provided on each of the opposite sides of the inner wall of the housing 40; a set of first pushing parts 400 includes multiple first pushing parts 400 arranged sequentially along the length direction of the housing 40; the two sets of pushing parts located on opposite sides of the inner wall of the housing 40 are staggered; a second pushing part 410 is provided on each of the opposite sides of the outer wall of the movable body 41; when the mold is opened, the movable body 41 moves relative to the housing 40 along its own height length so that the second pushing part 410 contacts the first pushing part 400; the two sets of first pushing parts 400 alternately push the two second pushing parts 410 so that the movable body 41 moves back and forth along the line connecting the two sets of first pushing parts 400 to strike the inner wall of the housing 40; the two second pushing parts 410 correspond one-to-one with the two sets of first pushing parts 400.

[0045] At least one of the first pushing part 400 and the second pushing part 410 can be made of an elastic material, allowing one of the first pushing part 400 and the second pushing part 410 to pass through the other by deformation, thereby avoiding the situation where the first pushing part 400 and the second pushing part 410 get stuck together.

[0046] The surface of the first pusher 400 facing the movable body 41 can be curved, which can guide the movable body 41 to slide in a direction away from itself, reducing the probability of the movable body 41 getting stuck.

[0047] When the mold is closed, the second pushers 410 on both sides of the movable body 41 of the first pusher 400, which are arranged in a staggered manner on both sides of the inner wall of the housing 40, are located in the initial position inside the housing 40. At this time, the second pusher 410 contacts the inclined surface of the first pusher 400 to form a pre-positioning fit. During the mold opening process, on the radial side of the movable body 41 (i.e., on the line connecting the two opposing sets of first pushing parts 400), the first parting mold 2 drives the movable body 41 to move in the mold opening direction, so that the second pushing part 410 begins to contact the inclined surface of the first pushing part 400. When one side of the second pushing part 410 contacts the inclined surface of the first pushing part 400 on the same side, the thrust generated by the mutual squeezing of the first pushing part 400 and the second pushing part 410 forces the movable body 41 to swing to the other side. Then, after the movable body 41 continues to move a certain distance under the drive of the first parting mold 2, the second pushing part 410 on the other side contacts the inclined surface of the first pushing part 400 on the same side. The thrust generated by the mutual squeezing of the first pushing part 400 and the second pushing part 410 on this side forces the movable body 41 to swing to the forward side, thereby making the movable body 41 reciprocate between the two opposing sets of first pushing parts 400. When the moving body 41 swings back and forth, its outer wall collides periodically with the inner wall of the shell 40, causing the shell 40 to vibrate laterally. The vibration energy is transmitted to the molded part 1 through the shell 40, destroying the bonding interface at the complex surface.

[0048] According to some embodiments of this application, optionally, such as Figures 4-8 As shown, the inner wall of the housing 40 is also provided with a guide groove 401; the guide groove 401 extends spirally along the length direction of the housing 40; the second pushing part 410 is adapted to the guide groove 401; the second pushing part 410 is farther away from the horizontal runner 5 than the first pushing part 400.

[0049] The inner side of the guide groove 401 can be coated with a smooth coating (such as copper-based graphite composite material) to reduce the coefficient of friction between the guide groove 401 and the second pushing part 410, so that the second pushing part 410 can slide more smoothly in the guide groove 401.

[0050] When the mold is opened, the movable body 41 first strikes the inner wall of the shell 40 under the push of the first push part 400, and then moves into the guide groove 401. The movable body 41 continues to move and rotates relative to the shell 40 under the constraint of the guide groove 401, so that the movable body 41 can transmit the residual vibration energy to the shell 40 along the spiral path, thereby improving the separation effect between the shell 40 and the molded part 1.

[0051] According to some embodiments of this application, optionally, such as Figures 4-6As shown, there are two guide grooves 401, and the two guide grooves 401 correspond one-to-one with the two second push parts 410.

[0052] When the movable body 41 rotates under the guidance of the guide groove 401 of the housing 40, the spiral trajectories of the second push parts 410 on both sides are strictly symmetrical, so as to avoid the movable body 41 from deflecting. Furthermore, the vibration kinetic energy of the movable body 41 can be transmitted to the paired guide grooves 401 through the symmetrical second push parts 410. The vibration energy is transmitted to the housing 40 in a symmetrical mode, forming a uniform ring vibration around the central axis, which can generate a balanced demolding force on the circumference of the housing 40.

[0053] According to some embodiments of this application, optionally, a protruding limiting ring is provided on the inner wall of the end of the housing 40 away from the horizontal runner 5; the minimum distance between the limiting ring and the outer surface of the movable body 41 is less than the size of the second pushing part 410 extending beyond the outer surface of the movable body 41.

[0054] The inner circumferential surface of the limiting ring can be provided with a protective layer with high hardness and smoothness. When the movable body 41 swings inside the housing 40, the movable body 41 may collide or rub against the outer wall of the limiting ring. Providing a protective layer on the inner circumferential surface of the limiting ring can protect the limiting ring from damage due to collisions, and can also reduce the friction between the movable body 41 and the limiting ring, thereby reducing the risk of mutual scratching and damage.

[0055] A protruding limiting ring is provided on the inner wall of the end of the shell 40 away from the horizontal runner 5. When the mold is opened, the movable body 41 is pulled and moved by the first parting mold 2 and hits the inner wall of the shell 40 for a period of time. Then, the second pushing part 410 of the movable body 41 contacts the limiting ring. Then, the second pushing part 410 pulls the shell through the limiting ring to separate the shell from the molded part 1, so that the shell can leave the molded part 1 together with the first parting mold 2. This eliminates the trouble of separating the shell from the molded part 1 separately later, and simplifies the use steps of the center gate die casting mold provided in this application.

[0056] According to some embodiments of this application, optionally, such as Figures 3-6 As shown, the movable body 41 includes a first segment 411 and a second segment 412 along its own length direction; the first segment 411 is located inside the shell 40; the second segment 412 is farther away from the horizontal runner 5 than the first segment 411; the diameter of the second segment 412 is larger than the diameter of the first segment 411; a first stepped surface is formed between the first segment 411 and the second segment 412; the first stepped surface is used to contact the end face of the shell 40 away from the horizontal runner 5.

[0057] The first step surface can be provided with an elastic rubber pad, so that when the first step surface collides with the housing 40, the rubber pad will undergo elastic deformation, thereby preventing the end face of the housing 40 and the first step surface from being damaged due to the collision.

[0058] The first segment 411 of the movable body 41 is fully inserted into the inner cavity of the shell 40. The first stepped surface of the second segment 412 is tightly fitted with the end face of the shell 40 away from the horizontal runner 5, forming a sealed interface to prevent the alloy liquid from seeping in. Before mold opening, the first stepped surface is tightly fitted with the end face of the shell 40 away from the horizontal runner 5, and the outer surface of the first segment 411 is fitted with the inner wall of the shell 40. When the shell 40 is subjected to pressure from the molded part 1, the first segment 411 and the first stepped surface can share and support the force on the shell 40, thereby reducing the risk of deformation of the shell 40 under the extrusion of the molded part 1. The second segment 412 has a larger diameter and acts as a vibrating mass block to enhance the vibration effect, reducing the demolding resistance at the bottom of the inner cavity of the molded part 1, making it easier for the shell 40 to separate from the molded part 1.

[0059] According to some embodiments of this application, optionally, such as Figures 3-4 As shown, the mounting hole 20 includes a first hole segment 200 and a second hole segment 201; the first hole segment 200 is closer to the second parting mold 3 than the second hole segment 201; the diameter of the second hole segment 201 is larger than the diameter of the first hole segment 200; a portion of the housing 40 is located inside the first hole segment 200; the outer wall of the housing 40 contacts the inner wall of the first hole segment 200; the movable body 41 also includes a third segment 413; the third segment 413 is located on the side of the second segment 412 away from the first segment 411; the third segment 413 is located in the second hole segment 201, and the diameter of the third segment 413 is larger than the diameter of the first hole segment 200; the second segment 412 is located inside the first hole segment 200, and there is a gap between the second segment 412 and the first hole segment 200.

[0060] The outer diameter of the housing 40 located inside the mounting hole 20 is larger than the outer diameter of the second section 412.

[0061] The outer wall of the housing 40 contacts the inner wall of the first hole section 200. The position of the housing 40 is determined by the hole wall of the mounting hole 20, preventing the position of the housing 40 located in the molding cavity from deviating from the center of the molding cavity. There is a gap between the second section 412 and the first hole section 200, allowing the movable body 41 to move radially along the first hole section 200 inside the first hole section 200 to strike the inner wall of the housing 40. The diameter of the third section 413 is larger than the hole diameter of the first hole section 200, allowing the third section 413 to stay in the second hole section 201, thereby being pulled apart from the housing 40 by the second mold 3.

[0062] According to some embodiments of this application, optionally, such as Figure 4 As shown, a second step surface is formed between the first hole segment 200 and the second hole segment 201; the third segment 413 is in contact with the second step surface.

[0063] Before the mold is opened, the third section 413 contacts the second step surface, the first section 411 contacts the inner wall of the shell 40 near the horizontal runner 5, and the end face of the shell 40 away from the horizontal runner 5 contacts the first step surface, so that the shell 40 and the moving body 41 can cooperate.

[0064] When the core 4 is inserted into the first mold 2, the movable body 41 moves synchronously with the housing 40, pushing the housing 40 into the molding cavity. The movable body 41 will move to contact the second step surface. The position of the second step surface determines the overall size of the core 4 extending into the molding cavity, so that the inner cavity shape of the molded part 1 can meet the rated requirements.

[0065] According to some embodiments of this application, optionally, such as Figure 9 As shown, this application provides a center gate die casting molding method, which uses the aforementioned center gate die casting molding mold, including the following steps: Step S100: Preheat the first mold 2, the second mold 3 and the core 4 and close the mold; Step S200: Inject molding liquid into the molding cavity, and then hold pressure, compensate for shrinkage and cool to obtain the molded part 1; Step S300: Separate the first mold 2 and the second mold 3, so that the movable body 41 hits the shell 40, and then separate the molded part 1 from the shell 40; Step S400: Separate the molded part 1 from the second mold 3 and the horizontal runner 5.

[0066] In step S100, the first mold 2, the second mold 3, and the core 4 are preheated in a gradient manner. The preheating temperature of the first mold 2 and the second mold 3 is higher than that of the core 4, thereby reducing the risk of the molding liquid cooling before the filling is completed. In step S200, the molding liquid is injected through the horizontal sprue 5 on the side of the second mold 3. The geometry of the molded part 1 is determined by staged injection (low-speed filling in the first section and high-speed compaction in the second section) to reduce flow defects. After injection, the molding cavity is immediately subjected to holding pressure, and then the shrinkage is continuously compensated through the horizontal sprue 5 to eliminate shrinkage cavities at the bottom of the deep cavity and the root of the boss. Finally, the mold and the molded part 1 inside are cooled. In step S300, the first mold 2 and the second mold 3 are opened, which drives the movable body 41 to move away from the horizontal sprue 5. After being pulled, the movable body 41 begins to pat the inner wall of the shell 40. The clamping force between the inner wall of the molded part 1 and the shell 40 is broken, and the molded part 1 vibrates under the drive of the shell 40. The vibration causes the adsorption force and mechanical engagement between the molded part 1 and the mold surface to fail, making the subsequent demolding of the molded part 1 smoother, and then the molded part 1 separates from the shell 40. In step S400, the molded part 1 is separated with the assistance of the ejector system after vibration: the inner wall of the molded part 1 uses a central ejector, and the outer edge of the molded part 1 uses a ring ejector, which works together to prevent the molded part 1 from deforming. The horizontal sprue 5 is connected to the molded part 1 through the cold slug well, and automatically breaks and separates during ejection. The center gate die casting method provided in this application weakens the connection effect between the molded part 1 and the core 4 and the inner wall of the molding cavity before separation, thereby solving the problem of demolding adhesion of the geometrically complex thin-walled molded part 1 and improving the yield of the molded part 1.

[0067] 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 center-gated die-casting mold for manufacturing thin-walled molded parts, characterized in that, include: The first and second molds are combined to form a molding cavity for molding the part. The core includes a housing and a movable body, with a portion of the movable body located inside the housing; Horizontal pouring channel; The first mold is provided with mounting holes; The core extends into the molding cavity through the mounting hole; The horizontal runner is located on the side of the second mold away from the first mold, and the horizontal runner is connected to the molding cavity; The housing is used to contact the molded part; The movable body is pulled apart from the shell by the first parting mold when the mold is opened; The movable body is configured to strike the inner wall of the housing when the first and second molds are opened, causing the housing to vibrate the molded part. The molded part vibrates to separate from the inner wall of the housing and the molding cavity.

2. The center gate die-casting mold according to claim 1, characterized in that, The inner diameter of the shell gradually increases from the end near the sprue to the end away from the sprue; The movable body moves up and down relative to the shell along its own height direction so that its outer surface is in contact with or separates from the inner wall of the shell.

3. The center gate die-casting mold according to claim 1, characterized in that, A set of first pushing parts is provided on each of the opposite sides of the inner wall of the housing; A set of first pushing parts includes a plurality of first pushing parts arranged sequentially along the length direction of the housing; Two sets of pushing parts located on opposite sides of the inner wall of the housing are staggered; A second pushing part is provided on each of the opposite sides of the outer wall of the movable body; When the mold is opened, the movable body moves relative to the shell along its own height length so that the second pushing part contacts the first pushing part; The two sets of first pushing parts alternately push the two second pushing parts to make the movable body reciprocate along the line connecting the two sets of first pushing parts to slap the inner wall of the shell; The two second propulsion units correspond one-to-one with the two sets of the first propulsion units.

4. The center gate die-casting mold according to claim 3, characterized in that, The inner wall of the housing is also provided with a guide groove; The guide groove extends spirally along the length of the housing; The second pushing part is adapted to the guide groove; The second pushing part is farther away from the horizontal runner than the first pushing part.

5. A center-gate die-casting mold according to claim 4, characterized in that, The number of guide grooves is two; The two guide grooves correspond one-to-one with the two second pushing parts.

6. A center-gate die-casting mold according to claim 3, characterized in that, A protruding limiting ring is provided on the inner wall of the end of the shell opposite to the horizontal sprue; The minimum distance between the limiting ring and the outer surface of the movable body is less than the dimension by which the second pushing part extends beyond the outer surface of the movable body.

7. A center-gate die-casting mold according to claim 1, characterized in that, The movable body comprises a first segment and a second segment along its own length; The first segment is located inside the housing; The second segment is farther away from the transverse runner than the first segment; The diameter of the second segment is larger than the diameter of the first segment; A first step surface is formed between the first segment and the second segment; The first stepped surface is used to contact the end face of the housing away from the transverse runner.

8. A center-gate die-casting mold according to claim 7, characterized in that, The mounting hole includes a first hole section and a second hole section; The first hole segment is closer to the second parting mold than the second hole segment; The diameter of the second hole segment is larger than the diameter of the first hole segment; Part of the housing is located inside the first hole section; The outer wall of the housing is in contact with the inner wall of the first hole section; The active body also includes a third segment; The third segment is located on the side of the second segment away from the first segment; The third segment is located in the second hole segment, and the diameter of the third segment is larger than the diameter of the first hole segment; The second segment is located inside the first hole segment, and there is a gap between the second segment and the first hole segment.

9. A center-gate die-casting mold according to claim 8, characterized in that, A second step surface is formed between the first hole segment and the second hole segment; The third segment is in contact with the second step surface.

10. A method for center-gate die casting, using a center-gate die casting mold as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step S100: Preheat the first mold, the second mold, and the core, and then close the mold. Step S200: Inject molding fluid into the molding cavity, then hold pressure, compensate for shrinkage, and cool to obtain the molded part; Step S300: Separate the first mold and the second mold, so that the movable body strikes the shell, and then separate the molded part from the shell; Step S400: Separate the molded part from the second parting mold and the horizontal runner.

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