Structure for automatic breaking of ring gate injection molding part in mold opening

Abstract

The invention relates to the technical field of injection molds, in particular to an automatic breaking structure for mold opening of a ring gate injection molding part, which comprises a separation table, a fixed table and an upper mold are respectively and movably mounted above and below the separation table, a fixed sleeve is mounted on the fixed table, and a glue inlet sleeve is mounted on the separation table. Through the structural design of sequential mold opening and the annular side gate, the mold is divided into a fixed table, a separation table and an upper mold, two-step mold opening actions of firstly breaking the gate and then taking a material head are utilized, and a precise annular gate formed by matching an insert pin with a conical surface of a rubber feeding sleeve is adopted. Automatic operation is achieved, follow-up manual sprue trimming is not needed, cost is saved, the annular sprue is beneficial to pressure transmission, product shrinkage and warping are prevented, and internal quality is guaranteed. Meanwhile, the position and size of the sprue are accurately controlled, and a foundation is laid for high-quality fracture.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and specifically to a structure for automatic mold breakage when opening an annular gate injection molded part. Background Technology

[0002] In the field of injection mold design and manufacturing, the gate design directly affects the quality of plastic parts, production efficiency, and the degree of subsequent automation. For the ubiquitous ring-shaped plastic parts, common gates include side gates, submarine gates, and spot gates. Side gates are beneficial for product pressure holding, but require later removal of the gate or the addition of an inner mold cutting structure, which increases production costs. Spot gates and submarine gates can achieve automatic gate disconnection. However, for gear products with high precision requirements, especially gears made of POM high-crystallinity material, the tooth shape requirements are high, so the gate form plays a crucial role.

[0003] Although traditional submarine gates or three-plate gates can be automatically broken by shearing force during mold opening or ejection, these structures are usually suitable for single-point injection. If applied to annular injection, it often requires the design of extremely complex parting surfaces or multi-point flow structures, resulting in a large mold structure, high manufacturing difficulty, and difficulty in ensuring the absolute balance of the annular flow.

[0004] In the prior art, such as the Chinese utility model patent with announcement number CN217621985U and patent name "Rotary Automatic Gate Cutting Mechanism for Injection Molds", it specifically includes a gate sleeve, a moving mold core and a pull pin set in the fixed mold core. Through the cooperation of the self-cutting channel section (whose axis is an arc) at the bottom of the gate sleeve and the pull pin, the gate is automatically cut off by rotational shearing during the mold opening process.

[0005] The aforementioned solutions are primarily designed for point gates or single gates. Their rotary cutting action relies on the curved material channel fixed by the gate sleeve, making it difficult to adapt to the balanced injection and synchronous cutting required for annular side gates. For annular plastic parts (such as gears), it is impossible to achieve precise forming and overall shearing of annular gates, and the structure is complex and difficult to adjust, making it impossible to guarantee the key dimensional requirements such as concentricity and cylindricity (≤0.02mm) required for high-precision gears.

[0006] The existing technology lacks a mold structure that can automatically and neatly cut off the annular side gate during the mold opening process, while ensuring the stability of high-precision plastic parts dimensions.

[0007] To address this issue, a structure for automatic mold breakage of injection molded parts with annular gates is proposed. Summary of the Invention

[0008] Technical problems to be solved To address the aforementioned shortcomings of existing technologies, this invention provides a structure for automatic breakage of injection molded parts with annular gates, which can solve the problem of burrs easily generated and affecting the key dimensions of the product when high-precision POM gear annular gates are automatically broken.

[0009] Technical solution To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a structure for automatic mold breaking of injection molded parts with annular gates, including a separation platform, a fixed platform and an upper mold respectively movably mounted above and below the separation platform, a fixed sleeve mounted on the fixed platform, and a glue inlet sleeve mounted on the separation platform; Wherein, the lower end of the injection sleeve cooperates with the insert pin set in the upper mold to form an annular injection gate, and a first driving mechanism is provided between the upper mold and the separation table to drive the upper mold to perform the first mold opening movement relative to the separation table, so that the workpiece is separated from the annular injection gate; A second driving mechanism is provided between the separating platform and the fixed platform to drive the separating platform to perform a second mold opening movement relative to the fixed platform, so that the inlet sleeve and the fixed sleeve are separated to expose the waste material. The inside of the injection sleeve, above the annular injection port, is provided with a step to limit the waste material during the first mold opening movement.

[0010] Furthermore, a rotary drive mechanism is provided between the separation platform and the injection sleeve. The rotary drive mechanism is used to drive the injection sleeve to rotate during the first mold opening movement, so that the workpiece is subjected to shear force at the annular injection gate and breaks.

[0011] Furthermore, a water jacket is installed on the upper mold, and the rotary drive mechanism includes an inclined groove and a vertical groove formed on the surface of the rubber inlet sleeve, as well as a push rod fixedly disposed on the inner wall of the water jacket. In the mold-closed state, the push rod is inserted at the beginning of the inclined groove. The first mold-opening motion drives the push rod to slide in the inclined groove, so as to drive the rubber sleeve to rotate through the inclined surface until the push rod enters the vertical groove.

[0012] Furthermore, the infeed sleeve is rotatably housed in an annular groove on the separation platform via a pressure block on its surface, and an annular spring that can store energy through the rotation of the infeed sleeve is connected between the pressure block and the inner wall of the annular groove.

[0013] Furthermore, it also includes a locking mechanism disposed on the separation platform, wherein a limit groove is formed in the separation platform, and the locking mechanism includes a limit rod disposed in the limit groove by a first spring; When the push rod slides into the vertical groove, the limiting insert rod is inserted into the vertical groove under the action of the first spring to prevent the rubber sleeve from rotating.

[0014] Furthermore, it also includes a reset mechanism disposed in the vertical groove. When the push rod slides upward in the vertical groove, the reset mechanism releases the locking of the limiting plug rod to the inlet sleeve, causing the annular spring to drive the inlet sleeve to reverse and reset, and guides the push rod back to the starting end of the inclined groove.

[0015] Furthermore, the reset mechanism includes an air pipe installed in the vertical groove and filled with a medium. An upper piston rod and a lower piston rod are slidably installed at the upper and lower ends of the air pipe, respectively. A push block is connected to the upper end of the upper piston rod, and a baffle is rotatably connected to the lower end of the lower piston rod through a first torsion spring shaft. When the mold is closed, the push rod pushes the baffle and the lower piston rod upward, and the medium pushes the upper piston rod and the push block upward. The inclined surface of the push block pushes the limiting insert rod out of the vertical groove.

[0016] Furthermore, a cold material storage groove is provided at the upper center of the insert pin, and a countersunk platform is provided on the glue inlet end face of the workpiece.

[0017] Furthermore, it also includes a scraping mechanism disposed below the injection sleeve, the scraping mechanism being located above the sinking platform, used to scrape the sinking platform surface of the workpiece during the first mold opening movement.

[0018] Furthermore, the scraping mechanism includes a rotating rod that is elastically hinged in the side groove below the rubber inlet sleeve, and the surface of the rotating rod is provided with a slot, in which a scraper is elastically and movably installed; When demolding, the rotating rod unfolds under the action of elastic force, causing the scraper to abut against the surface of the workpiece and scrape as the rubber sleeve rotates and moves downward.

[0019] Beneficial effects The technical solution provided by this invention has the following advantages compared with the prior art: This invention utilizes a sequential mold opening and annular side gate structure design to divide the mold into a fixed platform, a separation platform, and an upper mold. It employs a two-step mold opening action of first cutting the gate and then removing the sprue head, and uses a precision annular gate formed by the cooperation of the insert pin and the conical surface of the injection sleeve to achieve automated operation. This eliminates the need for subsequent manual gate trimming, saving costs. Furthermore, the annular gate facilitates pressure transmission, prevents product shrinkage and warping, and ensures internal quality. At the same time, the precise control of the gate position and size lays the foundation for high-quality fracture. By using a rotary shear gate breaking mechanism, and by setting push rods in the upper mold and opening connected inclined and vertical grooves on the surface of the gate sleeve, the linear motion of mold opening is converted into the rotational motion of the gate sleeve. This applies compound tensile and shear stress to the gate, improves the cross-sectional quality, and transforms plastic tensile fracture into brittle shear fracture, resulting in a flat and smooth cross-section. This fundamentally eliminates burrs and ensures that the concentricity and cylindricity of key parts such as gears are not affected by gate breakage. The reset and locking mechanism, which is a pneumatic-hydraulic linkage, is set up in the vertical groove. The reset mechanism includes an air pipe, a piston rod and a triangular push block. It works with the limit rod to release the lock by the mold closing force through the medium pressure and achieves automatic reset by the energy storage of the ring spring. It is driven by pure mechanical force without external power. The reset is accurate and the operation is reliable. It can automatically complete a series of actions such as unlocking, rotation reset and push rod return, which can ensure the consistency of mass production and the continuity of the automated process and ensure stable cycle. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a front cross-sectional view of the automatic annular side gate structure in an embodiment of the present invention; Figure 2 This is a schematic diagram of the side axis of the automatic annular side gate structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the automatic ring-shaped side gate structure in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the inlet sleeve structure in an embodiment of the present invention. Figure 5 This is a schematic diagram of the glue inlet sleeve installed in the annular groove in an embodiment of the present invention; Figure 6 This is a schematic diagram of the adhesive inlet sleeve structure in an embodiment of the present invention; Figure 7 for Figure 6 Enlarged schematic diagram of the structure at point A in the middle; Figure 8 for Figure 6 Enlarged schematic diagram of the structure at point B; Figure 9 This is a schematic diagram of the push rod drive in an embodiment of the present invention; Figure 10 This is a schematic diagram of the step structure in an embodiment of the present invention; Figure 11 This is a schematic diagram of the annular inlet structure in an embodiment of the present invention; Figure 12 This is a schematic diagram of the pin insert structure in an embodiment of the present invention.

[0022] The labels in the diagram represent: 1. Upper mold; 2. Insert pin; 201. Cold material storage tank; 3. Molding cavity; 4. Workpiece; 5. Separation platform; 501. Annular groove; 502. Limiting groove; 503. First spring; 504. Limiting rod; 6. Inlet sleeve; 601. Pressure block; 602. Annular spring; 603. Inclined groove; 604. Vertical groove; 605. Air pipe; 606. Upper piston rod; 607. Push block; 608, lower piston rod; 609, first torsion spring shaft; 610, baffle; 611, side groove; 612, second torsion spring shaft; 613, rotating rod; 614, slot; 615, folding spring; 616, scraper; 7, fixed platform; 8, hot runner; 9, fixed sleeve; 10, water jacket; 11, water channel; 12, settling platform; 13, annular inlet; 14, waste material; 15, step; 16, push rod. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0024] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] In the description of this embodiment, the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0027] The present invention will be further described below with reference to embodiments.

[0028] Example: Please refer to the appendix. Figure 1-12 This solution proposes a structure for automatic mold breakage when opening annular gate injection molded parts.

[0029] Specifically, in this embodiment, a movable separation platform 5 and an upper mold 1 are installed sequentially below the fixed platform 7.

[0030] A hot runner 8 and a fixing sleeve 9 are installed on the fixing platform 7, with the fixing sleeve 9 covering the outside of the hot runner 8.

[0031] A glue inlet sleeve 6 is installed on the separation platform 5, and the glue inlet sleeve 6 wraps around the outside of the fixed sleeve 9.

[0032] A water jacket 10 is installed on the upper mold 1. The water jacket 10 wraps around the outside of the glue inlet sleeve 6. At the same time, a water channel 11 is provided inside the upper mold 1. The glue inlet sleeve 6 is installed inside the water channel 11 to prevent the glue inlet position from overheating.

[0033] The upper mold 1 is located below the glue outlet position of the glue inlet sleeve 6 and has a molding cavity 3. The lower mold is located below the molding cavity 3, which is not shown in the figure. When the highly crystalline POM material is conveyed through the hot runner 8, it flows sequentially from the hot runner 8 into the inlet sleeve 6, and enters the molding cavity 3 through the lower opening of the inlet sleeve 6, where it is cooled to form the workpiece 4.

[0034] The lower mold is connected to a pin 2. The upper end of the pin 2 passes through the workpiece 4 and is inserted into the lower opening of the injection sleeve 6. When the POM high crystallinity material enters the molding cavity 3 through the injection sleeve 6, the workpiece 4 will form a shaft cavity at the center of the molding cavity 3, so that the POM high crystallinity material can form the shaft hole of the gear after cooling.

[0035] Meanwhile, the interior of the insert pin 2 is hollow to allow cooling water to pass through, thereby accelerating the cooling speed of the POM highly crystalline material in the molding cavity 3, so that the workpiece 4 can be formed quickly.

[0036] More specifically, the lower end of the inlet sleeve 6 is set to be conical, and the upper end of the insert pin 2 is also set to be conical, so that when the insert pin 2 is inserted into the lower opening of the inlet sleeve 6, it will be distributed concentrically, and the gap between the insert pin 2 and the inlet sleeve 6 forms an annular inlet 13.

[0037] This allows the highly crystalline POM material in the hot runner 8 to eventually enter the molding cavity 3 through the annular gate 13 and cool to form the workpiece 4. By setting the contact between the insert pin 2 and the injection sleeve 6 to be inclined, it can be ensured that the connection between the annular gate 13 and the workpiece 4 is the thinnest, which is beneficial for the gate to break cleanly and without residue when the workpiece 4 is removed.

[0038] Compared to a gate that is too small, which would result in high flow resistance and make it difficult to ensure that the pressure is effectively transmitted to the interior of workpiece 4; or the gate freezing in advance without subsequent pressure replenishment, causing the internal pressure of workpiece 4 to drop rapidly, which would cause the highly crystalline POM material to be sucked back.

[0039] The annular inlet 13 of this shape is beneficial for product pressure holding, preventing the backflow of molten POM highly crystalline material from causing uneven shrinkage, warping, voids, and other problems in the workpiece 4. It also effectively avoids the problem of weak product strength at the weld line location of the workpiece 4.

[0040] When the workpiece 4 in the molding cavity 3 cools and needs to be removed: First, the upper mold 1 is controlled to move downward relative to the separation table 5 by the drive component, so that the workpiece 4 and the material in the injection sleeve 6 break at the interface of the annular inlet 13 until the workpiece 4 is completely separated from the annular inlet 13.

[0041] During this process, a step 15 is provided inside the inlet sleeve 6 above the annular inlet 13. When the workpiece 4 and the material inside the inlet sleeve 6 separate, the step 15 will limit the material inside the inlet sleeve 6, so that the workpiece 4 and the material inside the inlet sleeve 6 can be neatly broken at the interface of the annular inlet 13 during the movement of the upper mold 1. At the same time, after the workpiece 4 is separated, the remaining material inside the inlet sleeve 6 will cool and form waste material 14.

[0042] After the upper mold 1 is completely removed, the separation stage 5 is moved downward relative to the fixed stage 7 by the drive component, which in turn causes the injection sleeve 6 to slide downward relative to the fixed sleeve 9, exposing the lower opening of the fixed sleeve 9.

[0043] At this point, by inserting a robotic arm between the insert sleeve 6 and the fixing sleeve 9, the waste material 14 retained in the insert sleeve 6 can be removed, thus facilitating the re-injection of POM high crystallinity material into the molding cavity 3 to form the workpiece 4 in the next work cycle.

[0044] It should be noted that a cold material storage tank 201 is provided at the center above the insert pin 2. When the workpiece 4 is removed from the molding cavity 3 and POM high-crystallinity material is poured into the workpiece 4 again, the material at the lower opening of the hot runner 8 will be cooled by the external environment, thus forming a partially solidified material. At this time, the POM high-crystallinity material in the hot runner 8 will first enter the cold material storage tank 201 during the flow process. After the cold material storage tank 201 is filled with POM high-crystallinity material, it will then enter the workpiece 4 through the annular inlet 13 between the insert pin 2 and the injection sleeve 6. Therefore, the cold material storage tank 201 can effectively solve the problem of cold material storage, thereby improving the quality of the product.

[0045] When the waste material 14 is removed, the cooled material in the cold material storage tank 201 and the waste material 14 are integrated and can be removed together. At the same time, a countersunk platform 12 is provided on the end face of the workpiece 4 where the glue is injected to prevent the size and use of the workpiece 4 from being affected after the gate is broken.

[0046] The difference is that the separation stage 5 has an annular groove 501 inside, and the inlet sleeve 6 is rotatably connected in the annular groove 501.

[0047] A rotary drive mechanism is installed between the separation platform 5 and the inlet sleeve 6; when the upper mold 1 moves downward relative to the separation platform 5, the rotary drive mechanism controls the inlet sleeve 6 to rotate synchronously.

[0048] This causes a torsional load to be generated at the connection between the workpiece 4 in the molding cavity 3 and the material in the inlet sleeve 6, with the annular inlet 13 as the interface.

[0049] Workpiece 4 is more prone to brittle fracture under shear action, which makes the fracture process faster and more controllable, and produces a flat, smooth and regular fracture surface. In contrast, POM, a highly crystalline material, undergoes significant plastic deformation under tension, and fracture occurs at the weakest point of the material, with an irregular and rough fracture surface that may produce burrs, protrusions or wires. Defects are easily left on the fracture surface of workpiece 4. Especially for high-precision gears, these micron-sized burrs can disrupt concentricity, leading to poor assembly, noise, and wear. The cross-sectional quality formed by shearing force in this method is much higher than that of tensile cross-section, which can maximize the geometric integrity and dimensional accuracy of key parts of workpiece 4 and avoid subsequent secondary processing.

[0050] The rotary drive mechanism includes an inclined groove 603 and a vertical groove 604 disposed on the surface of the inlet sleeve 6. The inclined groove 603 and the vertical groove 604 are connected, and the inclined groove 603 is inclined. It also includes a push rod 16 disposed on the inner wall of the water jacket 10. When the inlet sleeve 6 is not disengaged, the push rod 16 is inserted at the highest point of the inclined groove 603.

[0051] When the upper mold 1 moves downward relative to the separation table 5, it will drive the push rod 16 to slide relative to the inclined groove 603 through the separation table 5. Then, the push rod 16 will press down on the inclined groove 603, driving the rubber sleeve 6 to rotate in the annular groove 501.

[0052] Until the push rod 16 moves into the vertical groove 604, the upper mold 1 moves downward, which will cause the push rod 16 to slide downward in the vertical groove 604, and will not control the infeed sleeve 6 to rotate, until the push rod 16 is completely removed from the vertical groove 604.

[0053] A pressure block 601 is also connected to the surface of the inlet sleeve 6. The pressure block 601 is inserted into the annular groove 501. An annular spring 602 is connected to the surface of the pressure block 601. The other end of the annular spring 602 is connected to the inner wall of the annular groove 501.

[0054] When the infeed sleeve 6 starts to rotate under the action of the rotary drive mechanism, it will synchronously drive the pressure block 601 to rotate in the annular groove 501 and squeeze the annular spring 602 to realize the accumulation of elastic force for the infeed sleeve 6 to reset when the upper mold 1 is closed.

[0055] The separating platform 5 is also equipped with a locking mechanism to lock the rubber sleeve 6 after it has rotated a certain angle. The locking mechanism includes a limiting groove 502 on the separating platform 5, and a limiting rod 504 is connected to the limiting groove 502 by a first spring 503. When the rubber sleeve 6 is not rotated, the limiting rod 504 extends out of the limiting groove 502 and abuts against the outer surface of the rubber sleeve 6 under the elastic force of the first spring 503.

[0056] When the rotary drive mechanism drives the infeed sleeve 6 to rotate, the limiting rod 504 will rotate relative to the surface of the infeed sleeve 6 until the push rod 16 moves into the vertical groove 604. At the same time, the limiting rod 504 will also move into the vertical groove 604, thereby allowing the limiting rod 504 to be inserted into the vertical groove 604 under the elastic force of the first spring 503. This achieves rotational fixation of the infeed sleeve 6, preventing the infeed sleeve 6 from resetting under the elastic force of the ring spring 602, and simultaneously storing the elastic force of the ring spring 602.

[0057] A reset mechanism is also installed in the vertical groove 604. When the upper mold 1 closes, the accumulated spring force of the ring spring 602 is released to control the reset of the infeed sleeve 6 and to move the push rod 16 back to the highest point in the inclined groove 603, facilitating the next separation and breakage of the workpiece 4. The reset mechanism includes an air pipe 605 installed in the vertical groove 604. An upper piston rod 606 and a lower piston rod 608 are slidably installed at the upper and lower ends of the air pipe 605, respectively. At the same time, a medium is filled in the air pipe 605 between the upper piston rod 606 and the lower piston rod 608.

[0058] The upper end of the upper piston rod 606 is connected to a push block 607, which is triangular in shape. The lower end of the lower piston rod 608 is rotatably connected to a baffle 610 via a first torsion spring shaft 609. The baffle 610 always has an upward rotational force under the elastic force of the torsion spring inside the first torsion spring shaft 609, but it is limited and blocked by the lower piston rod 608, so it can only remain horizontal within the vertical groove 604.

[0059] When the push rod 16 moves into the vertical groove 604 and slides downward, it will abut against the surface of the baffle 610 and push the baffle 610 to overcome the torsion spring force in the first torsion spring shaft 609, thereby allowing the push rod 16 to be removed from the baffle 610 and out of the vertical groove 604.

[0060] When the upper mold 1 closes, the push rod 16 re-inserts into the vertical groove 604 and slides upward within it. During this process, the vertical groove 604 abuts against the surface of the baffle 610, and the baffle 610 pushes the lower piston rod 608 upward within the air pipe 605, thereby compressing the medium within the air pipe 605 and pushing the upper piston rod 606 to drive the push block 607 upward. As the push block 607 slides upward, its inclined surface abuts against the surface of the limiting rod 504 inserted into the vertical groove 604. As the upward height of the push block 607 increases, it gradually pushes the limiting rod 504 outward from the vertical groove 604, compressing the first spring 503 into the limiting groove 502.

[0061] Until the push rod 16 slides to the junction of the inclined groove 603 and the vertical groove 604, the limiting rod 504 completely moves out of the vertical groove 604. The vertical groove 604 will rotate under the elastic force of the ring spring 602. At this time, the push rod 16 will enter the inclined groove 603 and gradually move to the highest point of the inclined groove 603, i.e., the position where the injection sleeve 6 stops rotating, as the upper mold 1 continues to slide upward. During the mold closing process, the upward movement of the push rod 16 serves as the power source, triggering a mechanical sequence that integrates pneumatic-hydraulic linkage and inclined plane pushing. This allows the rotation lock of the injection sleeve 6 to be released at a precise moment, releasing the torsional elastic potential energy stored inside. This drives the injection sleeve 6 to automatically and reliably rotate back to the initial position, ensuring that the entire rotary shear gate cutting system is perfectly prepared for the next injection cycle.

[0062] It is worth noting that a scraping mechanism is also provided below the injection sleeve 6, and the scraping mechanism is located above the sink platen 12. When the upper mold 1 is disengaging, the scraping mechanism will be driven to unfold simultaneously, so that the scraping mechanism can polish the surface of the workpiece 4 at the sink platen 12, and perform online processing on the extremely small defects that may remain on the surface of the workpiece 4 sink platen 12 after the broken gate.

[0063] The scraping mechanism includes a side groove 611 located below the inlet sleeve 6. A rotating rod 613 is rotatably connected within the side groove 611 via a second torsion spring shaft 612. The rotating rod 613, under the action of a torsion spring inside the second torsion spring shaft 612, always possesses an outward rotating force. When the upper mold 1 is not disengaging the separating table 5, the rotating rod 613 abuts against the surface of the separating table 5 under the elastic force of the torsion spring inside the second torsion spring shaft 612. When the upper mold 1 disengages the separating table 5, the rotating rod 613 rotates outward under the elastic force of the torsion spring inside the second torsion spring shaft 612.

[0064] The surface of the rotating rod 613 is provided with a groove 614, and a scraper 616 is slidably connected in the groove 614 through a folding spring 615. When the rotating rod 613 rotates outward, the scraper 616 always abuts against the surface of the workpiece 4, i.e., the countersunk platform 12, under the elastic force of the folding spring 615.

[0065] As the injection sleeve 6 rotates and the upper mold 1 moves downward, the scraper 616 slides outward within the recess 12 and polishes the upper surface of the workpiece 4, completely eliminating any microscopic unevenness or flash that may remain after shearing and fracture. Physical scraping achieves a higher degree of smoothness and flatness on the workpiece surface, ensuring the dimensional accuracy of the gear end face as a key assembly datum. This integrates injection molding, gate breaking, and surface finishing, significantly improving the quality and reliability of the final product. The scraping mechanism consists of multiple sets of equidistantly distributed circumferentially arranged scrapers. Utilizing the natural mechanical motion during demolding, the rotation and downward movement of the injection sleeve 6 drives these circumferentially distributed scrapers 616 to perform scraping within the recess 12.

[0066] It enables online active trimming and polishing of key parts of the product (gate cross-section), further ensuring the absolute flatness of the upper surface of workpiece 4, and completely eliminating the potential risk to gear concentricity caused by micron-level burrs that may be generated by gate breakage, thereby improving the one-time molding qualification rate of the product to a near-perfect level.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A structure for automatic mold breakage of injection molded parts with annular gates, characterized in that, Includes a separation platform (5), with a fixed platform (7) and an upper mold (1) movably installed above and below the separation platform (5), a fixed sleeve (9) installed on the fixed platform (7), and an inlet sleeve (6) installed on the separation platform (5); Wherein, the lower end of the injection sleeve (6) cooperates with the insert pin (2) set in the upper mold (1) to form an annular injection gate (13), and a first driving mechanism is provided between the upper mold (1) and the separation table (5) to drive the upper mold (1) to perform the first mold opening movement relative to the separation table (5), so that the workpiece (4) is separated from the annular injection gate (13); A second driving mechanism is provided between the separating platform (5) and the fixed platform (7) to drive the separating platform (5) to perform a second mold opening movement relative to the fixed platform (7), so that the injection sleeve (6) separates from the fixed sleeve (9) to expose the waste material (14). The inside of the injection sleeve (6) is provided with a step (15) above the annular injection port (13) to limit the waste material (14) during the first mold opening movement.

2. The structure for automatic mold breakage of annular gate injection molded parts according to claim 1, characterized in that, A rotary drive mechanism is provided between the separation platform (5) and the injection sleeve (6). The rotary drive mechanism is used to drive the injection sleeve (6) to rotate during the first mold opening movement so that the workpiece (4) is subjected to shear force and breaks at the annular sprue (13).

3. The structure for automatic mold breakage of annular gate injection molded parts according to claim 2, characterized in that, The upper mold (1) is equipped with a water jacket (10), and the rotary drive mechanism includes a slanted groove (603) and a vertical groove (604) opened on the surface of the rubber inlet sleeve (6), and a push rod (16) fixedly set on the inner wall of the water jacket (10). In the mold-closed state, the push rod (16) is inserted at the beginning of the inclined groove (603). The first mold opening motion drives the push rod (16) to slide in the inclined groove (603) so as to drive the insert sleeve (6) to rotate through the inclined surface until the push rod (16) enters the vertical groove (604).

4. The structure for automatic mold breakage of annular gate injection molded parts according to claim 3, characterized in that, The inlet sleeve (6) is rotatably housed in the annular groove (501) provided on the separation platform (5) via a pressure block (601) provided on its surface. An annular spring (602) that can store energy through the rotation of the inlet sleeve (6) is connected between the pressure block (601) and the inner wall of the annular groove (501).

5. The structure for automatic mold breakage of annular gate injection molded parts according to claim 4, characterized in that, It also includes a locking mechanism disposed on the separation platform (5), wherein a limit groove (502) is provided in the separation platform (5), and the locking mechanism includes a limit rod (504) disposed in the limit groove (502) by a first spring (503). When the push rod (16) slides into the vertical groove (604), the limiting insert rod (504) is inserted into the vertical groove (604) under the action of the first spring (503) to prevent the rubber sleeve (6) from rotating.

6. The structure for automatic mold breakage of annular gate injection molded parts according to claim 5, characterized in that, It also includes a reset mechanism set in the vertical groove (604). When the push rod (16) slides upward in the vertical groove (604), the reset mechanism releases the locking of the limiting plug (504) to the inlet sleeve (6), so that the ring spring (602) drives the inlet sleeve (6) to reverse and reset, and guides the push rod (16) back to the starting end of the inclined groove (603).

7. The structure for automatic mold breakage of annular gate injection molded parts according to claim 6, characterized in that, The reset mechanism includes an air pipe (605) installed in a vertical groove (604) and filled with a medium. An upper piston rod (606) and a lower piston rod (608) are slidably installed at the upper and lower ends of the air pipe (605). A push block (607) is connected to the upper end of the upper piston rod (606), and a baffle (610) is rotatably connected to the lower end of the lower piston rod (608) through a first torsion spring shaft (609). When the mold is closed, the push rod (16) pushes the baffle (610) and the lower piston rod (608) to move upward, and pushes the upper piston rod (606) and the push block (607) to move upward through the medium. The inclined surface of the push block (607) pushes the limiting insert rod (504) out of the vertical groove (604).

8. The structure for automatic mold breakage of annular gate injection molded parts according to claim 1, characterized in that, The upper center of the insert (2) is provided with a cold material storage groove (201), and the glue inlet end face of the workpiece (4) is provided with a recessed platform (12).

9. A structure for automatic mold breakage of annular gate injection molded parts according to claim 8, characterized in that, It also includes a scraping mechanism located below the injection sleeve (6), which is located above the sink platen (12) and is used to scrape the surface of the sink platen (12) of the workpiece (4) during the first mold opening movement.

10. A structure for automatic mold breakage of annular gate injection molded parts according to claim 9, characterized in that, The scraping mechanism includes a rotating rod (613) that is elastically hinged in the side groove (611) below the rubber inlet sleeve (6). The surface of the rotating rod (613) is provided with a slot (614), and a scraper (616) is elastically and movably installed in the slot (614). When demolding, the rotating rod (613) unfolds under the action of elastic force, so that the scraper (616) abuts against the surface of the workpiece (4) and scrapes as the rubber sleeve (6) rotates and moves down.

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