An arc-shaped undercut rotating core-pulling mechanism for injection molds

Abstract

This invention discloses a rotary core-pulling mechanism for an injection mold with an arc-shaped undercut, comprising a movable seat, a drive block, an arc-shaped core-pulling block, a linkage mechanism, and a blocking and limiting component. A linear actuator drives the drive block to sequentially complete a first stroke and a second stroke. In the first stroke, the drive block moves relative to the restricted movable seat, forcing the arc-shaped core-pulling block to rotate via the linkage mechanism, thereby precisely disengaging it from the arc-shaped undercut groove of the plastic part and completing the initial demolding. In the second stroke, the drive block presses down on the blocking and limiting component to release the locking of the movable seat, and drives the movable seat and the arc-shaped core-pulling block to exit linearly together, completing the full core-pulling. This invention achieves a two-stage core-pulling action of "first rotational disengagement, then linear exit" using a single power source, greatly simplifying the mold structure, reducing manufacturing costs, and improving the reliability and stability of the operation. It is particularly suitable for mold structures with limited internal space.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and in particular to an arc-shaped undercut rotating core-pulling mechanism for injection molds. Background Technology

[0002] Injection molding is a widely used processing method for plastic products, which uses injection molds to give plastic shapes. For plastic parts with complex structures, undercut features are often designed on their side walls, which can cause interference when the mold opens, making it difficult for the product to be demolded smoothly. To solve this problem, the mold usually needs to be designed with a special side core-pulling mechanism.

[0003] Currently, for conventional straight undercuts, a sliding block driven by a slanted guide post is typically used for straight core pulling, a technology that is relatively mature. However, when the undercut on the plastic part has an arc-shaped structure (i.e., the direction of the undercut groove is a spatial curve related to the mold opening direction), the traditional straight core pulling mechanism is not applicable. If a straight core pulling is forcibly used, it will interfere with the arc-shaped structure of the plastic part, leading to core pulling failure or even damage to the plastic part or mold.

[0004] like Figure 12 As shown, one side of the plastic part 4 has an arc-shaped undercut 41. Existing technologies employ rotary core-pulling solutions for demolding the arc-shaped undercut. These mechanisms typically use gears and racks, hydraulic motors, or oscillating cylinders to drive the core-pulling block along an arc-shaped trajectory to achieve demolding. However, this approach has significant drawbacks: after the simple rotational motion, the core-pulling block may still partially remain within the mold cavity, requiring an additional drive source or mechanism to remove it entirely, further increasing the system's complexity and instability. Therefore, there is an urgent need for a highly efficient core-pulling mechanism for demolding the arc-shaped undercut. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide an arc-shaped undercut rotating core-pulling mechanism for injection molds.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an arc-shaped undercut rotary core-pulling mechanism for injection molds, comprising a fixed template and a movable template. The fixed template is provided with a cavity insert, the movable template is provided with a core insert, and the movable template is provided with a core-pulling mechanism. The core-pulling mechanism directly or indirectly cooperates with the core insert to form an arc-shaped undercut groove for a plastic part. The core-pulling mechanism includes: a movable seat, slidably disposed on the movable template; a driving block, driven to move relative to the movable seat by a linear driver; an arc-shaped core-pulling block for forming the arc-shaped undercut groove, the arc-shaped core-pulling block being hinged to the movable seat or a component connected to the movable seat; and a linkage mechanism connected to the driving block and the movable template. Between the arc-shaped core-pulling blocks; a blocking and limiting component, disposed on the moving template, can prevent the movable seat from moving in the core-pulling direction; the driving block has a first stroke and a second stroke under the drive of the linear actuator; in the first stroke, the driving block moves relative to the movable seat restricted by the blocking and limiting component, and drives the arc-shaped core-pulling block to rotate around its hinge point through the linkage mechanism, thereby disengaging from the arc-shaped undercut groove of the plastic part; in the second stroke, the driving block acts on the blocking and limiting component, causing it to release the movement restriction on the movable seat, and drives the movable seat to pull the arc-shaped core-pulling block out together along the core-pulling direction.

[0007] As a preferred embodiment of the present invention, the movable seat is provided with a movable cavity, and one side of the movable cavity is provided with an opening for the movement of the arc-shaped core-pulling block. A connecting seat is fixed inside the movable cavity, and the portion of the arc-shaped core-pulling block and the connecting seat located inside the movable cavity are hinged.

[0008] As a preferred embodiment of the present invention, the movable seat is provided with an elongated hole, and the arc-shaped core-pulling block is fixed with a guide pin. The guide pin extends into the elongated hole, thereby restricting the rotational movement of the arc-shaped core-pulling block within the trajectory range of the elongated hole.

[0009] As a preferred embodiment of the present invention, the linkage mechanism is a linkage rod, one end of which is hinged to the drive block, and the other end is directly or indirectly hinged to the arc-shaped core-pulling block; the movable seat is provided with a movable groove, and the drive block is at least partially slidably fitted in the movable groove; when the drive block moves from the left side of the movable groove to the right blocking surface, it reaches the end position of the first stroke.

[0010] As a preferred embodiment of the present invention, the drive block includes a T-shaped connecting portion, the head of which is slidably engaged and confined within the movable groove.

[0011] As a preferred embodiment of the present invention, the bottom of the arc-shaped core-pulling block is symmetrically provided with two swing arms, each swing arm being hinged to the connecting seat; the end of the arc-shaped core-pulling block facing the linkage rod is provided with a swing groove, the swing groove is provided with a rotating shaft, one end of the linkage rod is sleeved on the rotating shaft and can swing up and down relative to the swing groove.

[0012] As a preferred embodiment of the present invention, the blocking and limiting assembly includes a limiting seat and a compression spring; the moving template has a groove adapted to the shape of the limiting seat, and the two ends of the compression spring are respectively connected to the limiting seat and the bottom wall of the groove; the connecting seat has an arc-shaped positioning port, and one corner of the limiting seat is limited to the arc-shaped positioning port under the action of the compression spring; the upper part of the limiting seat has a sliding groove, and the right side of the sliding groove has a guide slope; the driving block includes a moving block that cooperates with the sliding groove, and the moving block has a mating slope adapted to the guide slope; when the arc-shaped core-pulling block is located in the arc-shaped undercut groove of the plastic part, the moving block is located on the left side of the sliding groove and there is a gap between the mating slope and the guide slope; when the arc-shaped core-pulling block is pulled out of the arc-shaped undercut groove, the mating slope of the moving block abuts against the guide slope, and the moving block continues to move, driving the limiting seat to press down and disengage from the arc-shaped positioning port, and driving the arc-shaped core-pulling block and the moving seat to exit synchronously along the core-pulling direction as a whole.

[0013] As a preferred embodiment of the present invention, the moving template is provided with a mounting plate on the side away from the core insert, the linear actuator is a hydraulic cylinder, the hydraulic cylinder is fixed on the mounting plate and its output shaft is connected to the drive block; the mounting plate is provided with fixing pins on both sides, the movable seat is provided with mounting holes on the side facing the mounting plate, and a return spring is sleeved on the fixing pin, the two ends of the return spring abutting against the mounting plate and the mounting hole respectively.

[0014] As a preferred embodiment of the present invention, it further includes an inclined ejector mechanism, which includes an inclined ejector seat, an inclined ejector rod, a fixed block, an inclined slider, and an inclined slide block; the inclined ejector seat and the core insert together form a structure adapted to the inner shape of the plastic part; after mold closing, an injection cavity is formed between the cavity insert, the core insert, and the inclined slide block; the inclined slide block and the arc-shaped core-pulling block correspond to the inner and outer sides of the plastic part, respectively; the inclined slider slides in slidable engagement with the inclined groove of the inclined slide block, the fixed block is installed on the moving template, and the inclined ejector rod is inclinedly inserted into the inclined hole of the fixed block, with its two ends fixedly connected to the inclined slide block and the inclined slider, respectively.

[0015] Compared with existing technologies, the advantages of this invention are as follows: This invention innovatively decomposes the core-pulling process into two consecutive strokes driven by a linear actuator. The first stroke prioritizes a precise rotational motion, allowing the arc-shaped core block to detach from the complex arc-shaped undercut without damage; the second stroke then performs a linear withdrawal motion, completely removing the core block from the mold cavity. This "rotation-then-straight" two-stage action sequence fundamentally avoids problems such as tearing, scratching, or even damage to the plastic part that may be caused by forced one-time core pulling, greatly improving the reliability of the core-pulling action and the quality of the demolded product. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the moving mold part in this invention;

[0017] Figure 2 This is a schematic diagram of the moving mold part in this invention;

[0018] Figure 3 This is a cross-sectional view of the moving mold portion in this invention;

[0019] Figure 4 yes Figure 3 A magnified view of part A;

[0020] Figure 5 This is a schematic diagram of the structure of the drive block and the limiting seat in this invention.

[0021] Figure 6 This is a schematic diagram of the bottom structure of the moving mold part in this invention;

[0022] Figure 7 This is a schematic diagram of the core-pulling mechanism in this invention;

[0023] Figure 8 This is a schematic diagram of the linkage mechanism in this invention;

[0024] Figure 9 This is a schematic diagram of the arc-shaped core-pulling block in this invention;

[0025] Figure 10 This is a schematic diagram of the structure of the movable seat in this invention;

[0026] Figure 11 This is a schematic diagram of the structure of the bottom of the movable seat in this invention;

[0027] Figure 12 This is a schematic diagram of the structure of a plastic part in the background art.

[0028] Reference numerals: 1. Moving template; 11. Core insert; 12. Groove; 13. Mounting plate; 131. Fixing pin; 2. Core pulling mechanism; 21. Movable seat; 211. Movable cavity; 212. Opening; 213. Connecting seat; 2131. Arc-shaped positioning port; 214. Oblong hole; 215. Guide pin; 216. Movable groove; 2161. Blocking surface; 217. Mounting hole; 22. Return spring; 23. Linear actuator; 24. Arc-shaped core pulling block; 241. Swing arm; 242. Swing groove; 24 3. Rotating shaft; 25. Linkage mechanism; 251. Linkage rod; 26. Blocking and limiting assembly; 261. Limiting seat; 262. Compression spring; 263. Slide groove; 2631. Guide slope; 27. Drive block; 271. T-shaped connecting part; 272. Head; 273. Moving block; 2731. Mating slope; 3. Inclined top mechanism; 31. Inclined top seat; 32. Inclined top rod; 33. Fixing block; 34. Inclined slider; 35. Inclined slide block; 351. Inclined slide groove; 4. Plastic part; 41. Arc-shaped undercut groove. Detailed Implementation

[0029] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] like Figure 1-11The figure shows a rotary core-pulling mechanism 2 for an injection mold with an arc-shaped undercut slider. It includes a fixed template and a movable template 1. The fixed template (not shown) has a cavity insert (not shown), and the movable template 1 has a core insert 11. The movable template 1 also has a core-pulling mechanism 2, which directly or indirectly cooperates with the core insert 11 to form an arc-shaped undercut groove 41 in the plastic part (for injection molded storage boxes). The core-pulling mechanism 2 includes: a movable seat 21, slidably mounted on the movable template 1; a driving block 27, driven to move relative to the movable seat 21 by a linear driver 23; an arc-shaped core-pulling block 24 for forming the arc-shaped undercut groove 41, the arc-shaped core-pulling block 24 being hinged to the movable seat 21 or a component connected to the movable seat 21; and a linkage mechanism 25 connected to the movable template 1. Between the driving block 27 and the arc-shaped core-pulling block 24; a blocking and limiting component 26 is disposed on the moving template 1 to prevent the movable seat 21 from moving in the core-pulling direction; the driving block 27 has a first stroke and a second stroke under the drive of the linear actuator 23; in the first stroke, the driving block 27 moves relative to the movable seat 21 restricted by the blocking and limiting component 26, and drives the arc-shaped core-pulling block 24 to rotate around its hinge point through the linkage mechanism 25, thereby disengaging from the arc-shaped undercut groove 41 of the plastic part; in the second stroke, the driving block 27 acts on the blocking and limiting component 26, causing it to release the movement restriction on the movable seat 21, and drives the movable seat 21 to drive the arc-shaped core-pulling block 24 to exit together in the core-pulling direction.

[0032] The core improvement of this application lies in the specific structure of the core-pulling mechanism 2 and its secondary core-pulling control action of "rotation first, then linear movement". Specifically, a single linear actuator 23 drives the drive block 27, and through its cooperation with the blocking and limiting component 26, it sequentially completes two action sequences: rotating the arc-shaped core-pulling block 24 to disengage from the undercut and then linearly exiting the entire block. In addition, other components of the mold, such as but not limited to: the conventional ejection action of the inclined ejector mechanism 3 (e.g., the inclined slide 35 pushed by the ejector rod), the basic structure of the mold frame, the cooling system of the cavity and core, the guiding mechanism, and the conventional operating procedures of the injection molding machine, all employ mature technologies known in the art and fall within the scope of existing technology. Those skilled in the art can, based on existing technical knowledge, connect and cooperate these parts with the innovative parts of this invention without any creative effort.

[0033] This invention innovatively decomposes the core-pulling process into two consecutive strokes, driven by a linear actuator 23. The first stroke prioritizes a precise rotational motion, allowing the arc-shaped core-pulling block 24 to disengage from the complex arc-shaped undercut without damage. The second stroke then executes a linear withdrawal motion, completely removing the core-pulling block from the mold cavity. This "rotation-then-straight" two-stage action sequence fundamentally avoids problems such as tearing, scratching, or even damage to the plastic part that may result from forced one-time core pulling, greatly improving the reliability of the core-pulling action and the quality of the demolded product. This invention cleverly utilizes the relative movement between the drive block 27 and the movable seat 21, as well as the cooperation of the blocking and limiting component 26, to achieve the conversion and transmission of two motion forms through a simple linkage mechanism 25 (such as the linkage rod 251, guide pin 215, and elongated hole 214). It eliminates the need for multiple drive systems such as gear racks and pinions and hydraulic motors, greatly simplifying the overall structure and reducing the space occupied inside the mold. It is particularly suitable for multi-cavity mold designs with compact structures and densely arranged cavities. The entire core-pulling process requires only a common linear actuator 23 (such as a hydraulic cylinder) as a power source, eliminating the need for separate drive devices for rotation and linear motion. This not only simplifies the hydraulic or electrical control system of the mold and reduces the failure rate, but also significantly reduces manufacturing, procurement, and maintenance costs, resulting in a clear economic advantage.

[0034] The movable base 21 has a movable cavity 211, and one side of the movable cavity 211 has an opening 212 for the arc-shaped core-pulling block 24 to move. A connecting seat 213 is fixed inside the movable cavity 211, and the portion of the arc-shaped core-pulling block 24 that is connected to the connecting seat 213 within the movable cavity 211 is hinged. The movable base 21 has an elongated hole 214, and a guide pin 215 is fixed to the arc-shaped core-pulling block 24. The guide pin 215 extends into the elongated hole 214, restricting the rotational movement of the arc-shaped core-pulling block 24 within the trajectory range of the elongated hole 214. Through the cooperation of the guide pin 215 and the elongated hole 214, the rotational trajectory of the arc-shaped core-pulling block 24 is precisely restricted, ensuring the stability and repeatability of the operation.

[0035] One end of the linkage rod 251 is hinged to the drive block 27, and the other end is directly or indirectly hinged to the arc-shaped core-pulling block 24; the movable seat 21 is provided with a movable groove 216, and the drive block 27 is at least partially slidably engaged in the movable groove 216; when the drive block 27 moves from the left side of the movable groove 216 to the right blocking surface 2161, it reaches the end position of the first stroke. In this embodiment, the drive block 27 includes a T-shaped connecting part 271, the head 272 of which is slidably engaged and confined within the movable groove 216.

[0036] Two swing arms 241 are symmetrically arranged at the bottom of the arc-shaped core-pulling block 24, and each swing arm 241 is hinged to the connecting seat 213. The arc-shaped core-pulling block 24 has a swing groove 242 at one end facing the linkage rod 251. A rotating shaft 243 is provided in the swing groove 242. One end of the linkage rod 251 is sleeved on the rotating shaft 243 and can swing up and down relative to the swing groove 242.

[0037] The blocking and limiting assembly 26 includes a limiting seat 261 and a compression spring 262; the moving template 1 has a groove 12 adapted to the shape of the limiting seat 261, and the two ends of the compression spring 262 are respectively connected to the limiting seat 261 and the bottom wall of the groove 12; the connecting seat 213 has an arc-shaped positioning port 2131, and one corner of the limiting seat 261 is limited to the arc-shaped positioning port 2131 under the elastic force of the compression spring 262; the upper part of the limiting seat 261 has a sliding groove 263, and the right side of the sliding groove 263 has a guide slope 2631; the driving block 27 includes a moving block 273 that cooperates with the sliding groove 263, and the moving block 273 has a shape adapted to the guide slope 2631. The mating inclined surface 2731; when the arc-shaped core-pulling block 24 is located in the arc-shaped undercut groove 41 of the plastic part, the moving block 273 is located on the left side of the slide groove 263 and there is a gap between the mating inclined surface 2731 and the guiding inclined surface 2631; when the arc-shaped core-pulling block 24 is pulled out of the arc-shaped undercut groove 41, the mating inclined surface 2731 of the moving block 273 abuts against the guiding inclined surface 2631 (corresponding to the end position of the first stroke when the driving block 27 moves from the left side of the movable groove 216 to the right blocking surface 2161), and continues to move the driving limit seat 261 down to disengage from the arc-shaped positioning port 2131, and drives the arc-shaped core-pulling block 24 and the movable seat 21 to exit synchronously along the core-pulling direction as a whole.

[0038] A mounting plate 13 is provided on the side of the moving template 1 away from the core insert 11. The linear actuator 23 is a hydraulic cylinder, which is fixed on the mounting plate 13 and its output shaft is connected to the drive block 27. Fixing pins 131 are symmetrically provided on both sides of the mounting plate 13. Mounting holes 217 are symmetrically provided on the side of the movable seat 21 facing the mounting plate 13. A return spring 22 is sleeved on the fixing pin 131, and the two ends of the return spring 22 abut against the mounting plate 13 and the mounting hole 217, respectively. The blocking and limiting assembly 26 (such as the limiting seat 261 and the spring) not only provides reliable mechanical limiting, but is also a tubular factor for achieving initial core pulling, which needs to ensure that the position of the movable seat 21 remains relatively fixed during the first stroke.

[0039] It also includes a slanted ejector mechanism 3, which comprises a slanted ejector seat 31, a slanted ejector rod 32, a fixed block 33, a slanted slider 34, and a slanted slide block 35. The slanted ejector seat 31 and the core insert 11 together form a structure adapted to the inner shape of the plastic part. After mold closing, an injection cavity is formed between the cavity insert, the core insert 11, and the slanted slide block 35. The slanted slide block 35 and the arc-shaped core-pulling block 24 correspond to the inner and outer sides of the plastic part, respectively. The slanted slider 34 slides in the slanted groove of the slanted slide block 35. The fixed block 33 is installed on the moving template 1. The slanted ejector rod 32 is obliquely inserted into the slanted hole of the fixed block 33, and its two ends are fixedly connected to the slanted slide block 35 and the slanted slider 34, respectively. The arc-shaped rotating core-pulling mechanism 2 and the slanted ejector mechanism 3 are integrated into one mold. The inclined ejector mechanism 3 is driven by an independent ejection system (such as an ejector rod, not shown in the figure, which is the prior art) to move the inclined slide block 35. Through the cooperation of the inclined ejector rod 32 and the inclined slide block 34, the linear ejection motion is converted into inclined sliding, thereby reliably completing the demolding of the plastic part.

[0040] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An injection mold arc reverse buckle rotary core-pulling mechanism, comprising a fixed mold plate and a movable mold plate (1), a cavity insert is arranged on the fixed mold plate, a core insert (11) is arranged on the movable mold plate (1), a core-pulling mechanism (2) is arranged on the movable mold plate (1), the core-pulling mechanism (2) directly or indirectly cooperates with the core insert (11) to form an arc reverse buckle groove (41) of a plastic part, characterized in that: The core-pulling mechanism (2) comprises: a movable seat (21) slidably arranged on the movable die plate (1); a driving block (27) driven by a linear driver (23) to move relative to the movable seat (21); an arc-shaped core-pulling block (24) for forming the arc-shaped undercut groove (41), the arc-shaped core-pulling block (24) being hinged to the movable seat (21) or a component connected with the movable seat (21); a linkage mechanism (25) connected between the driving block (27) and the arc-shaped core-pulling block (24); a blocking and limiting assembly (26) arranged on the movable die plate (1) and capable of blocking the movable seat (21) from moving in the core-pulling direction; the driving block (27) has a first stroke and a second stroke under the driving of the linear driver (23); in the first stroke, the driving block (27) moves relative to the movable seat (21) blocked by the blocking and limiting assembly (26) and drives the arc-shaped core-pulling block (24) to rotate around the hinge point thereof so as to be separated from the arc-shaped undercut groove (41) of the plastic part; in the second stroke, the driving block (27) acts on the blocking and limiting assembly (26) to remove the movement limitation of the movable seat (21) and drive the movable seat (21) to move together with the arc-shaped core-pulling block (24) in the core-pulling direction. ​ 2. The injection mold undercut rotation core mechanism of claim 1, wherein: The movable seat (21) is provided with a movable cavity (211), one side of the movable cavity (211) is provided with an opening (212) for the movement of the arc-shaped core-pulling block (24), the movable cavity (211) is fixedly provided with a connecting seat (213), and the arc-shaped core-pulling block (24) and the connecting seat (213) are hinged in the movable cavity (211).

3. The injection mold undercut rotation core mechanism of claim 2, wherein: The movable seat (21) is provided with an oblong hole (214), the arc-shaped core-pulling block (24) is fixedly provided with a guide pin (215), and the guide pin (215) extends into the oblong hole (214) to limit the rotational movement of the arc-shaped core-pulling block (24) within the track range of the oblong hole (214).

4. An injection mold undercut rotation core mechanism according to claim 2 or 3, characterized in that: The linkage mechanism (25) is a linkage rod (251), one end of the linkage rod (251) is hinged to the driving block (27), the other end of the linkage rod (251) is directly or indirectly hinged to the arc-shaped core-pulling block (24), the movable seat (21) is provided with a movable groove (216), and the driving block (27) is at least partially slidably fitted in the movable groove (216); when the driving block (27) moves from the left side of the movable groove (216) to the right blocking surface (2161), the driving block (27) reaches the end position of the first stroke.

5. The injection mold undercut rotation core mechanism of claim 4, wherein: The driving block (27) comprises a T-shaped connecting portion (271), and a head portion (272) of the T-shaped connecting portion (271) is slidably fitted and limited in the movable groove (216).

6. The injection mold undercut rotation core mechanism of claim 4, wherein: The arc-shaped core-pulling block (24) is symmetrically provided with two swing arms (241) at the bottom, and each swing arm (241) is hingedly connected with the connecting seat (213); the arc-shaped core-pulling block (24) is provided with a swing groove (242) at one end facing the linkage rod (251), and the swing groove (242) is provided with a rotating shaft (243), and one end of the linkage rod (251) is sleeved on the rotating shaft (243) and can swing up and down relative to the swing groove (242).

7. The injection mold undercut rotation core mechanism of claim 2, wherein: The blocking and limiting assembly (26) comprises a limiting seat (261) and a compression spring (262); the movable die plate (1) is provided with a groove (12) which is adapted in shape to the limiting seat (261); the two ends of the compression spring (262) are connected with the limiting seat (261) and the bottom wall of the groove (12) respectively; the connecting seat (213) is provided with an arc-shaped positioning opening (2131), and one corner of the limiting seat (261) is limited in the arc-shaped positioning opening (2131) under the elastic force of the compression spring (262); the upper part of the limiting seat (261) is provided with a sliding groove (263), and the right side of the sliding groove (263) is provided with a guide inclined surface (2631); the driving block (27) comprises a moving block (273) matched with the sliding groove (263), and the moving block (273) has a matching inclined surface (2731) matched with the guide inclined surface (2631); when the arc-shaped core-pulling block (24) is located in the arc-shaped reverse buckling groove (41) of the plastic part, the moving block (273) is located on the left side of the sliding groove (263), and a gap is left between the matching inclined surface (2731) and the guide inclined surface (2631); when the arc-shaped core-pulling block (24) is pulled away from the arc-shaped reverse buckling groove (41), the matching inclined surface (2731) of the moving block (273) abuts against the guide inclined surface (2631), the driving limiting seat (261) is continuously moved to press and disengage from the arc-shaped positioning opening (2131), and the arc-shaped core-pulling block (24) and the movable seat (21) are synchronously withdrawn as a whole along the core-pulling direction.

8. The injection mold undercut rotation core mechanism of claim 1, wherein: The movable die plate (1) is provided with a mounting plate (13) away from the core insert block (11), the linear driver (23) is a hydraulic cylinder which is fixed on the mounting plate (13) and whose output shaft is connected with the driving block (27); the mounting plate (13) is symmetrically provided with a fixed pin (131) on both sides, the movable seat (21) is symmetrically provided with a mounting hole (217) on the side facing the mounting plate (13), and the fixed pin (131) is sleeved with a reset spring (22), and the two ends of the reset spring (22) abut against the mounting plate (13) and the mounting hole (217) respectively.

9. The injection mold undercut rotation core mechanism of claim 1, wherein: Also include the inclined top mechanism (3), the inclined top mechanism (3) includes inclined top seat (31), inclined top rod (32), fixed block (33), inclined slide block (34) and inclined slide seat (35);The inclined top seat (31) and the core insert (11) form the structure that is adapted to the shape inside the plastic part together;After clamping, the cavity insert, core insert (11) and inclined slide seat (35) form injection cavity;The inclined slide seat (35) and the arc core-pulling block (24) correspond to the inside and outside of the plastic part respectively;The inclined slide block (34) and the inclined slide seat (35) are slidably connected, the fixed block (33) is installed on the movable die plate (1), the inclined top rod (32) is obliquely arranged in the inclined hole of the fixed block (33), and both ends thereof are fixedly connected with the inclined slide seat (35) and the inclined slide block (34) respectively.

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