A core-pulling precision mold
By designing a core-pulling precision mold, the problem of difficult demolding when traditional injection molds handle complex plastic products was solved, enabling smooth molding and demolding of complex structures and improving the ease of use of the mold.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUIZHOU RENGUAN TECH MOULD CO LTD
- Filing Date
- 2025-05-26
- Publication Date
- 2026-07-03
AI Technical Summary
Existing injection molds are prone to locking when processing plastic products with side concave, side convex, or inward buckling structures that are inconsistent with the mold opening direction, making effective demolding impossible. This is especially true when multi-directional core pulling is required, where the convenience of using traditional molds is insufficient.
Design a core-pulling precision mold, including an upper mold, a lower mold, a gating structure, an ejection structure, a movable core structure, a core-pulling transmission structure, and a core-pulling drive mechanism. The core-pulling drive mechanism drives the core-pulling transmission structure, causing the movable core structure to detach from the molding cavity, thus achieving smooth demolding of complex plastic products.
It improves the molding convenience of plastic products, can effectively handle plastic products with complex structures, avoids deformation or damage caused by forced demolding, and improves the ease of use of molds.
Smart Images
Figure CN224446668U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of injection molds, and in particular to a core-pulling precision mold. Background Technology
[0002] Injection molds are specialized tools used in plastic molding processes. Their core function is to inject molten plastic into a pre-set cavity under high temperature and pressure, and after cooling and solidification, obtain plastic products with specific shapes, sizes and properties.
[0003] Specifically, injection molds are indispensable equipment in the injection molding process. They are typically precision-machined from steel and consist of two main parts: a fixed mold and a moving mold. After the mold closes, a closed cavity is formed. Molten plastic is injected into the cavity under the high pressure of the injection molding machine. After cooling, the mold is opened to remove the finished product. Injection molds can efficiently produce plastic products with complex geometries and high precision requirements, such as electronic components, automotive parts, and appliance casings. Therefore, injection molds, through precise structural design and process control, transform liquid plastic into a solid finished product, making them core equipment for large-scale industrial production.
[0004] Based on this, Chinese patent CN118927542B discloses a front-mold submersible injection mold for preventing residue buildup. It includes a front mold and a corresponding rear mold. The front mold has a water inlet and a front water inlet groove connected to the water inlet. The rear mold has a rear water inlet groove, which matches to form a water inlet channel connected to the molding cavity. The rear mold has a spring block and a mounting cavity for placing the spring block. The spring block is slidably disposed within the mounting cavity, and the rear water inlet groove passes through the mounting cavity. A limiting block extends laterally from the tail end of the spring block, and a limiting cavity extends laterally from the tail end of the mounting cavity, higher than the limiting block. The limiting block is slidably disposed within the limiting cavity. An elastic element is also provided within the mounting cavity, with one end abutting the spring block and the other end abutting the rear mold, for driving the limiting block to move towards the front mold.
[0005] However, the injection molds disclosed above still have technical problems related to insufficient ease of use. Specifically, the disclosed molds are mainly based on a two-plate mold, which can only be used to process plastic products with simple structures. In actual applications of injection molding, plastic products often have structures that are inconsistent with the mold opening direction. In this case, conventional injection molds will lock up and become unusable. Specifically, when plastic products have side concave, side convex, or internal buckling structures that are inconsistent with the mold opening direction, such as threaded holes, snaps, or barbs, traditional injection molds cannot demold directly. Some plastic products even require multi-directional core pulling within the same mold, such as lateral and longitudinal linkage. In this case, a core pulling mechanism needs to be introduced into the injection mold to solve the problem of the injection mold being unable to demold. For example, the core pulling mechanism moves laterally or obliquely, allowing the core to exit from inside or outside the product before mold opening, avoiding deformation or damage caused by forced demolding. Utility Model Content
[0006] Therefore, it is necessary to provide a core-pulling precision mold to address the technical issue of how to improve the molding convenience of plastic products.
[0007] A core-pulling precision mold includes: an upper mold, a lower mold, a gating structure, an ejector structure, an upper mold core, a lower mold core, a forming cavity, a movable core structure, a core-pulling transmission structure, and a core-pulling drive mechanism. The upper mold and the lower mold are movably opened and closed relative to each other. The gating structure is disposed in the upper mold, and the ejector structure is disposed in the lower mold. The upper mold core is disposed in the upper mold, and the lower mold core is disposed in the lower mold, with the upper mold core and the lower mold core being opposite to each other. The forming cavity is respectively disposed in the upper mold core and the lower mold core. The gating structure is connected to the forming cavity, and the ejector structure is connected to the forming cavity. The movable core structure is movably inserted through the lower mold and the lower mold core, and the movable core structure is movably connected to the forming cavity. The core-pulling transmission structure is drively connected to the movable core structure, and the core-pulling drive mechanism is drively connected to the core-pulling transmission structure.
[0008] Furthermore, the movable core structure is provided with a core body and a core connecting cavity.
[0009] Furthermore, one end of the core body is movably connected to the molding cavity, and the other end of the core body is provided with a core connecting cavity; the core body is movably inserted into the lower mold and the lower mold core.
[0010] Furthermore, the core-pulling transmission structure is provided with a first spur rack, a transmission gear, and a transmission shaft.
[0011] Furthermore, the first spur rack is disposed in the core connecting cavity, and the transmission gear meshes with the first spur rack; the transmission rack is sleeved on the transmission shaft, and the transmission shaft is movably disposed in the lower mold.
[0012] Furthermore, the core-pulling drive mechanism includes a power cylinder body, a piston push rod, a second straight rack, a rack support frame, and a drive gear.
[0013] Furthermore, the power cylinder body is fixedly mounted on the side of the lower mold, and the power cylinder body is drivenly connected to the piston push rod; one end of the piston push rod is movably mounted in the power cylinder body, and the other end of the movable push rod is connected to the second spur rack; the rack support frame is mounted on the lower side of the lower mold, and the second spur rack is movably connected to the rack support frame; the drive gear is mounted between the rack support frame and at one end of the transmission shaft, and the drive gear meshes with the second spur rack.
[0014] Furthermore, the ejection structure includes a base plate, a push plate, an ejection guide rod, a pad, a guide post, a spring, and an ejection sliding sleeve.
[0015] Furthermore, the base plate is disposed at the bottom of the lower mold, the push plate is movably disposed on the base plate, the lower end of the ejector guide rod is connected to the base plate, and the upper end of the ejector guide rod is connected to the molding cavity.
[0016] Furthermore, the pad is positioned above the push plate, and a plurality of guide posts are evenly distributed between the pad and the base plate. A plurality of springs are evenly distributed between the pad and the push plate, and each spring is movably sleeved on a corresponding guide post. The lower end of the ejector sleeve is connected to the push plate, and the upper end of the ejector sleeve is connected to the molding cavity. The ejector sleeve is movably sleeved on the ejector guide rod.
[0017] In summary, this utility model discloses a core-pulling precision mold comprising an upper mold, a lower mold, a gating structure, an ejection structure, an upper mold core, a lower mold core, a forming cavity, a movable core structure, a core-pulling transmission structure, and a core-pulling drive mechanism. The upper mold and the lower mold are movably opened and closed relative to each other. The gating structure is disposed in the upper mold, and the ejection structure is disposed in the lower mold. The upper mold core is disposed in the upper mold, and the lower mold core is disposed in the lower mold, with the upper mold core and the lower mold core being movably arranged opposite each other. The forming cavity is disposed in the upper mold core and the lower mold core, and the gating structure is connected to the forming cavity, as is the ejection structure. The movable core structure is movably inserted through the lower mold and the lower mold core, and is movably connected to the forming cavity. The core-pulling transmission structure is drively connected to the movable core structure, and the core-pulling drive mechanism is drively connected to the core-pulling transmission structure. After the plastic product is cooled and pressurized in the molding cavity, the core-pulling drive mechanism can drive the core-pulling transmission structure to move within the lower mold and the lower mold core. This causes the movable core structure to first disengage from the preset position of the plastic product in the molding cavity. Then, the upper mold and the lower mold are opened separately by the external injection molding machine's operating mechanism, thereby realizing the processing and molding of the special structure of the plastic product. This significantly improves the molding convenience of the plastic product. Therefore, this utility model, a core-pulling precision mold, solves the technical problem of how to improve the molding convenience of plastic products. Attached Figure Description
[0018] Figure 1 This is a structural schematic diagram of a core-pulling precision mold according to the present invention;
[0019] Figure 2 This is a schematic diagram of the structure of a core-pulling precision mold of this utility model from another direction;
[0020] Figure 3 This is a cross-sectional structural diagram of one section of a core-pulling precision mold according to the present invention.
[0021] Figure 4 This is a cross-sectional structural diagram of another section of a core-pulling precision mold according to the present invention. Detailed Implementation
[0022] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.
[0023] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0026] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0027] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0028] Please refer to the following: Figures 1 to 4 This utility model discloses a core-pulling precision mold comprising: an upper mold 1, a lower mold 2, a gating structure 3, an ejection structure 4, an upper mold core 5, a lower mold core 6, a molding cavity 7, a movable core structure 8, a core-pulling transmission structure 9, and a core-pulling drive mechanism 10; the upper mold 1 and the lower mold 2 are movably opened and closed relative to each other; the gating structure 3 is disposed in the upper mold 1, and the ejection structure 4 is disposed in the lower mold 2; the upper mold core 5 is disposed in the upper mold 1, and the lower mold core 6 is disposed in the lower mold 2; the upper mold core 5 and the lower mold core 6 are connected in a series of movable opening and closing mechanisms. The lower mold cores 6 are arranged opposite to each other; the molding cavities 7 are respectively disposed in the upper mold cores 5 and the lower mold cores 6, the casting structure 3 is connected to the molding cavity 7, and the ejection structure 4 is connected to the molding cavity 7; the movable core structure 8 is movably disposed in the lower mold 2 and the lower mold cores 6, and the movable core structure 8 is movably connected to the molding cavity 7; the core pulling transmission structure 9 is drivingly connected to the movable core structure 8, and the core pulling drive mechanism 10 is drivingly connected to the core pulling transmission structure 9.
[0029] Specifically, in the working process of this core-pulling precision mold, the upper mold 1 and the lower mold 2 are driven by different drive components of an external injection molding machine. When the upper mold 1 and the lower mold 2 are driven to merge and connect, the upper mold core 5 and the lower mold core 6 also merge and connect together. At this time, the external injection molding machine can inject molten plastic into the molding cavity 7 through the gating structure 3. When the molten plastic is molded in the molding cavity 7, the position of the movable core structure 8 connected in the molding cavity 7 can assist in the molding of the preset position of the plastic product to be molded. For example, it can assist in the molding of structures such as side concavity, side convexity, or internal buckling that are inconsistent with the mold opening direction of the upper mold 1 and the lower mold 2. Subsequently, after the plastic product is cooled and pressurized in the molding cavity 7, the core-pulling drive mechanism 10 can drive the core-pulling transmission structure 9 to move within the lower mold 2 and the lower mold core 6. This causes the movable core structure 8 to first disengage from the preset position of the plastic product in the molding cavity 7. Then, the upper mold 1 and the lower mold 2 are opened and moved away by the external injection molding machine's operating mechanism, thereby realizing the processing and molding of the special structure of the plastic product. This significantly improves the molding convenience of the plastic product.
[0030] Furthermore, the movable core structure 8 is provided with a core body 801 and a core connecting cavity 802; one end of the core body 801 is movably connected to the molding cavity 7, and the other end of the core body 801 is provided with the core connecting cavity 802; the core body 801 is movably inserted into the lower mold 2 and the lower mold core 6.
[0031] Furthermore, the core-pulling transmission structure 9 is provided with a first spur rack 901, a transmission gear 902, and a transmission shaft 903; the first spur rack 901 is disposed in the core connecting cavity 802, and the transmission gear 902 is meshed with the first spur rack 901; the transmission gear 902 is sleeved on the transmission shaft 903, and the transmission shaft 903 is movably disposed in the lower mold 2.
[0032] Furthermore, the core-pulling drive mechanism 10 is provided with a power cylinder body 1001, a piston push rod 1002, a second spur rack 1003, a rack support frame 1004, and a drive gear 1005; the power cylinder body 1001 is fixedly disposed on the side of the lower mold 2, and the power cylinder body 1001 is drivenly connected to the piston push rod 1002; one end of the piston push rod 1002 is movably disposed in the power cylinder body 1001, and the other end of the piston push rod 1002 is connected to the second spur rack 1003; the rack support frame 1004 is disposed on the lower side of the lower mold 2, and the second spur rack 1003 is movably connected in the rack support frame 1004; the drive gear 1005 is disposed between the rack support frame 1004 at one end of the transmission shaft 903, and the drive gear 1005 is meshed with the second spur rack 1003.
[0033] Specifically, before the upper mold 1 and the lower mold 2 open, when the plastic product molded in the molding cavity 7 needs to undergo a core-pulling action before demolding, the power cylinder body 1001 starts and first drives the piston push rod 1002 to retract. At this time, the piston push rod 1002 drives the drive gear 1005 to rotate through meshing transmission. Then, the drive gear 1005 drives the drive shaft 903 to rotate in the lower part of the lower mold 2, thereby driving the transmission gear 902 to rotate. The transmission gear 902 then drives the first spur rack 901 to move through meshing transmission, so that the first spur rack 901 drives the core body 801 to move down along the lower mold 2 and the lower mold core 6 through the core connecting cavity 802, until one end of the core body 801 is separated from the preset position of the plastic product in the molding cavity 7. After this, the upper mold 1 and the lower mold 2 will not be stuck after opening.
[0034] More specifically, the power cylinder body 1001 can be a hydraulic cylinder or a pneumatic cylinder; as long as it can drive the piston rod 1002 to reciprocate within it, it is acceptable. The rack support frame 1004 through which the second rack 1003 moves can support and guide the movement of the rack.
[0035] Furthermore, the gating structure 3 has a gating gate 301 and a runner 302; the gating gate 301 is disposed on the upper mold 1, and the runner 302 is disposed in the upper mold 1 and the upper mold core 5, and the runner 302 is connected to the molding cavity 7. Specifically, molten plastic from an external injection molding machine can enter the runner 302 through the gating gate 301, and then flow into the molding cavity 7 through the runner 302 to achieve the molding of the plastic product.
[0036] Furthermore, the ejection structure 4 includes a base plate 401, a push plate 402, an ejection guide rod 403, a pad 404, a guide post 405, a spring 406, and an ejection sleeve 407. Specifically, the base plate 401 is disposed at the bottom of the lower mold 2, the push plate 402 is movably disposed on the base plate 401, the lower end of the ejection guide rod 403 is connected to the base plate 401, and the upper end of the ejection guide rod 403 is connected to the molding cavity 7; the pad 404 is disposed on the push plate 401. Above the mold 2, a plurality of guide posts 405 are evenly distributed between the pad 404 and the base plate 401, and a plurality of springs 406 are evenly distributed between the pad 404 and the push plate 402. Each spring 406 is movably sleeved on a guide post 405. The lower end of the ejector sleeve 407 is connected to the push plate 402, and the upper end of the ejector sleeve 407 is connected to the molding cavity 7. The ejector sleeve 407 is movably sleeved on the ejector guide rod 403. The base plate 401, the push plate 402, and the pad 404 are all disposed within the lower mold 2.
[0037] Specifically, when the upper mold 1 and the lower mold 2 open, the ejection power mechanism of the external injection molding machine can drive the push plate 402 to move it away from the base plate 401. When the push plate 402 moves upward, it compresses each spring 406 and simultaneously pushes the bottom end of the ejection sleeve 407, causing the ejection sleeve 407 to move upward along the ejection guide rod 403 until the top of the ejection sleeve 407 ejects the molded plastic product out of the molding cavity 7. Afterward, the external ejection power mechanism retracts, and the push plate 402 also retracts simultaneously under the restoring force of the springs 406 until its bottom abuts against the base plate 401. At this time, the ejection sleeve 407 is also driven downward along the ejection guide rod 403 to reset.
[0038] In summary, this utility model discloses a core-pulling precision mold comprising an upper mold 1, a lower mold 2, a gating structure 3, an ejection structure 4, an upper mold core 5, a lower mold core 6, a molding cavity 7, a movable core structure 8, a core-pulling transmission structure 9, and a core-pulling drive mechanism 10. The upper mold 1 and the lower mold 2 are movably opened and closed relative to each other. The gating structure 3 is disposed in the upper mold 1, and the ejection structure 4 is disposed in the lower mold 2. The upper mold core 5 is disposed in the upper mold 1, and the lower mold core 6 is disposed in the lower mold 2. The upper mold core 5 and the lower mold core 6 are arranged opposite to each other; the molding cavity 7 is respectively arranged in the upper mold core 5 and the lower mold core 6, the casting structure 3 is connected to the molding cavity 7, and the ejection structure 4 is connected to the molding cavity 7; the movable core structure 8 is movably inserted in the lower mold 2 and the lower mold core 6, and the movable core structure 8 is movably connected to the molding cavity 7; the core pulling transmission structure 9 is drivingly connected to the movable core structure 8, and the core pulling drive mechanism 10 is drivingly connected to the core pulling transmission structure 9. After the plastic product is cooled and pressurized in the molding cavity 7, the core-pulling drive mechanism 10 can drive the core-pulling transmission structure 9 to move within the lower mold 2 and the lower mold core 6. This causes the movable core structure 8 to first disengage from the preset position of the plastic product in the molding cavity 7. Then, the upper mold 1 and the lower mold 2 are opened and moved away by the external injection molding machine's operating mechanism, thereby realizing the processing and molding of the special structure of the plastic product. This significantly improves the molding convenience of the plastic product. Therefore, this utility model, a core-pulling precision mold, solves the technical problem of how to improve the molding convenience of plastic products.
[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0040] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A core-pulling precision mold, characterized in that, It includes: The upper mold (1), lower mold (2), gating structure (3), ejection structure (4), upper mold core (5), lower mold core (6), molding cavity (7), movable core structure (8), core pulling transmission structure (9), and core pulling drive mechanism (10) are configured to open and close relative to each other. The gating structure (3) is located in the upper mold (1), and the ejection structure (4) is located in the lower mold (2). The upper mold core (5) is located in the upper mold (1), and the lower mold core (6) is located in the lower mold (2). (6) Relative arrangement; the molding cavity (7) is respectively disposed in the upper mold core (5) and the lower mold core (6), the casting structure (3) is connected to the molding cavity (7), and the ejection structure (4) is connected to the molding cavity (7); the movable core structure (8) is movably disposed in the lower mold (2) and the lower mold core (6), and the movable core structure (8) is movably connected to the molding cavity (7); the core pulling transmission structure (9) is drivenly connected to the movable core structure (8), and the core pulling drive mechanism (10) is drivenly connected to the core pulling transmission structure (9).
2. A precision core-draw die according to claim 1, wherein: The movable core structure (8) is provided with a core body (801) and a core connecting cavity (802).
3. A precision core-draw die according to claim 2, wherein: One end of the core body (801) is movably connected to the molding cavity (7), and the other end of the core body (801) is provided with a core connecting cavity (802); the core body (801) is movably inserted into the lower mold (2) and the lower mold core (6).
4. A precision core-draw die according to claim 3, wherein: The core-pulling transmission structure (9) is provided with a first straight rack (901), a transmission gear (902) and a transmission shaft (903).
5. A precision core-draw die according to claim 4, wherein: The first spur rack (901) is disposed in the core connecting cavity (802), and the transmission gear (902) meshes with the first spur rack (901); the transmission gear (902) is sleeved on the transmission shaft (903), and the transmission shaft (903) is movably disposed in the lower mold (2).
6. A precision core-draw die according to claim 5, wherein: The core-pulling drive mechanism (10) is provided with a power cylinder body (1001), a piston push rod (1002), a second straight rack (1003), a rack support frame (1004), and a drive gear (1005).
7. A precision core-draw die according to claim 6, wherein: The power cylinder body (1001) is fixedly disposed on the side of the lower mold (2), and the power cylinder body (1001) is drivenly connected to the piston push rod (1002); one end of the piston push rod (1002) is movably disposed in the power cylinder body (1001), and the other end of the piston push rod (1002) is connected to the second straight rack (1003); the rack support frame (1004) is disposed on the lower side of the lower mold (2), and the second straight rack (1003) is movably connected in the rack support frame (1004); the drive gear (1005) is disposed between the rack support frame (1004) and at one end of the transmission shaft (903), and the drive gear (1005) is meshed with the second straight rack (1003).
8. A precision core-draw die according to claim 7, wherein: The ejection structure (4) has a base plate (401), a push plate (402), an ejection guide rod (403), a pad plate (404), a guide post (405), a spring (406), and an ejection sleeve (407).
9. A precision core-draw die according to claim 8, wherein: The base plate (401) is disposed at the bottom of the lower mold (2), the push plate (402) is movably disposed on the base plate (401), the lower end of the ejector guide rod (403) is connected to the base plate (401), and the upper end of the ejector guide rod (403) is connected to the molding cavity (7).
10. A core-pulling precision mold according to claim 9, characterized in that: The pad (404) is disposed above the push plate (402). A plurality of guide posts (405) are evenly distributed between the pad (404) and the base plate (401). A plurality of springs (406) are evenly distributed between the pad (404) and the push plate (402). Each spring (406) is movably sleeved on a guide post (405). The lower end of the ejector sleeve (407) is connected to the push plate (402), and the upper end of the ejector sleeve (407) is connected to the molding cavity (7). The ejector sleeve (407) is movably sleeved on the ejector guide rod (403).